Circuit interrupter with a trip mechanism having a biased latch

Information

  • Patent Grant
  • 6262645
  • Patent Number
    6,262,645
  • Date Filed
    Friday, August 27, 1999
    25 years ago
  • Date Issued
    Tuesday, July 17, 2001
    23 years ago
Abstract
A circuit interrupter including a housing, separable main contacts disposed in the housing, and an operating mechanism disposed in the housing and interconnected with the contacts. The operating mechanism includes a cradle for moving from a first position to a second position in the event of a tripping operation and thereby causing the contacts to open. A trip mechanism is disposed in the housing and includes a rotatable trip bar assembly that, when selectively rotated, generates a tripping operation. The trip mechanism includes a rotatable latch that engages the trip bar assembly and the cradle and keeps the cradle in the first position when a tripping operation has not occurred. The trip mechanism further includes a tension member that is positioned to bias the latch in a first rotational direction.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




The present invention relates to circuit interrupters generally and, more specifically, to those kinds of circuit interrupters having a trip mechanism with a latch.




2. Description of the Art




Molded case circuit breakers and interrupters are well known in the art as exemplified by U.S. patent No. 4,503,408 issued Mar. 5, 1985, to Mrenna et al., and U.S. patent No. 5,910,760 issued Jun. 8, 1999 to Malingowski, et al., each of which is assigned to the assignee of the present application and incorporated herein by reference.




Circuit interrupters include trip mechanisms that can be activated in a variety of manners so as to set in motion a tripping operation. These trip mechanisms often employ a rotatable trip bar assembly that, when selectively rotated, releases a portion of the operating mechanism to thereby generate a tripping operation. In the normal, non-tripped state of such an interrupter, a rotatable latch is connected between the trip bar assembly and the operating mechanism portion in order to lock the operating mechanism portion in a non-tripped position until the trip bar assembly is rotated.




When the trip bar assembly is rotated in order to initiate a tripping operation, the trip bar assembly becomes disengaged from the latch, enabling the latch to rotate under the influence of the operating mechanism portion. It has been noted that this rotation can leave the latch in an over-rotated position that is non-conducive to a resetting operation. As such, the prior art has provided stops in order to limit the rotation of the latch due to the influence of the operating mechanism portion. Unfortunately, variability in parts can compromise the ability of such a stop to prevent over-rotation. As such, it would be advantageous if a way existed by which to ensure that over-rotation of the latch did not occur.




SUMMARY OF THE INVENTION




The present invention provides a circuit interrupter that meets all of the above-identified needs.




In accordance with the present invention, a circuit interrupter is provided which includes a housing, separable main contacts disposed in the housing, and an operating mechanism disposed in the housing and interconnected with the contacts. The operating mechanism includes a cradle for moving from a first position to a second position in the event of a tripping operation and thereby causing the contacts to open. Also provided is a trip mechanism disposed in the housing and including a rotatable trip bar assembly that, when selectively rotated, generates a tripping operation. The trip mechanism includes a rotatable latch that engages the trip bar assembly and the cradle and keeps the cradle in the first position when a tripping operation has not occurred. The trip mechanism further includes a tension member that is positioned to bias the latch in a first rotational direction.











This and other objects and advantages of the present invention will become apparent from a reading of the following description of the preferred embodiment taken in connection with the attached drawings.




BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is an orthogonal view of a molded case circuit breaker embodying the present invention.





FIG. 2

is an exploded view of the base and cover of the circuit interrupter of FIG.


1


.





FIG. 3

is side elevational view of an internal portion of the circuit interrupter of FIG.


1


.





FIG. 4

is an orthogonal view of the internal portions of the circuit interrupter of

FIG. 1

without the base and cover.





FIG. 5

is an orthogonal view of an internal portion of the circuit interrupter of

FIG. 1

including the operating mechanism.





FIG. 6

is a side elevational, partially broken away view of the operating mechanism of the circuit interrupter of

FIG. 1

with the contacts and the handle in the OFF disposition.





FIG. 7

is a side elevational, partially broken away view of the operating mechanism with the contacts and the handle in the ON disposition.





FIG. 8

is a side elevational, partially broken away view of the operating mechanism with the contacts and the handle in the TRIPPED disposition.





FIG. 9

is a side elevational, partially broken away view of the operating mechanism during a resetting operation.





FIG. 10A

is an orthogonal view of the trip bar assembly of the trip mechanism of the circuit interrupter of FIG.


1


.





FIG. 10B

is another orthogonal view of the trip bar assembly of FIG.


10


A.





FIG. 10C

is another orthogonal view of the trip bar assembly of

FIG. 10A

showing the groove therein.





FIG. 10D

is an orthogonal view of the torsion spring of the trip bar assembly shown in FIG.


10


A.





FIG. 10E

is an orthogonal view the trip bar assembly of

FIG. 10A

with the spring of

FIG. 10D

attached.





FIG. 10F

is another orthogonal view of the trip bar assembly and spring of FIG.


10


E.





FIG. 11

is an orthogonal view of a latch used in connection with the trip mechanism of the circuit interrupter of FIG.


1


.





FIG. 12

is an orthogonal view of the sideplate assembly, cradle, latch, and trip bar assembly of an internal portion of the circuit interrupter of FIG.


1


.





FIG. 13

is an exploded view of the internal portion of the circuit interrupter shown in FIG.


12


.





FIG. 14

is an orthogonal, partially broken away view of the engagement between the latch and the trip bar assembly of the circuit interrupter of FIG.


1


.





FIG. 15

is an orthogonal, partially broken away view of the base and an internal portion of the circuit interrupter including the push-to-trip actuator of the trip mechanism.





FIG. 16A

is an orthogonal view of the push-to-trip actuator shown in FIG.


15


.





FIG. 16B

is another orthogonal view of the push-to-trip actuator shown in FIG.


15


.





FIG. 17

is an orthogonal view of the button of the push-to-trip actuator shown in FIG.


15


.





FIG. 18A

is an orthogonal view of the automatic trip assembly of the trip mechanism of the circuit interrupter of FIG.


1


.





FIG. 18B

is another orthogonal view of the automatic trip assembly shown in FIG.


18


A.





FIG. 18C

is an orthogonal view of the automatic trip assembly shown in

FIG. 18A

showing the initial positioning step of its armature.





FIG. 19A

is an orthogonal view of the magnetic yoke of the automatic trip assembly shown in FIG.


18


A.





FIG. 19B

is another orthogonal view of the magnetic yoke of the automatic trip assembly shown in FIG.


18


A.





FIG. 20

is an orthogonal view of the bimetal of the automatic trip assembly shown in FIG.


18


A.





FIG. 21

is an orthogonal view of the armature of the automatic trip assembly shown in FIG.


18


A.





FIG. 22A

is an orthogonal view of the load terminal of the automatic trip assembly shown in FIG.


18


A.





FIG. 22B

is another orthogonal view of the load terminal of the automatic trip assembly shown in FIG.


18


A.





FIG. 23

is an orthogonal, partially broken away view of the base of the circuit interrupter of

FIG. 1

showing the grooves in which the load terminal of the automatic trip assembly is inserted.





FIG. 24

is an orthogonal, partially broken away view similar to

FIG. 23

showing the base with the load terminal inserted.





FIG. 25

is a side elevational view of the base of the circuit interrupter of

FIG. 1

showing the tapered sides thereof.





FIG. 26

is an orthogonal, partially broken away view of the cover of the circuit interrupter of

FIG. 1

showing an abutment wall that contacts the inserted load terminal of FIG.


24


.





FIG. 27

is another orthogonal view of the cover and abutment wall shown in FIG.


26


.





FIG. 28A

is an orthogonal view of another embodiment of the load terminal that may be implemented in the automatic trip assembly of the trip mechanism of the circuit interrupter.





FIG. 28B

is another orthogonal view of the alternative embodiment of the load terminal shown in FIG.


28


A.





FIG. 28C

is another orthogonal view of the alternative embodiment of the load terminal showing the underside of the connector portion.





FIG. 29

is an orthogonal view of the self-retaining collar used in connection with the line and load terminals of the circuit interrupter of FIG.


1


.





FIG. 30A

is a side elevational view of the cradle of the operating mechanism of the circuit interrupter.





FIG. 30B

is an orthogonal view of the cradle pivot pin of the operating mechanism of the circuit interrupter shown in FIG.


1


.





FIG. 31

is an orthogonal view of the handle assembly of the operating mechanism of the circuit interrupter shown in FIG.


1


.





FIG. 32

is an orthogonal view of the cam housing of the crossbar assembly of the operating mechanism.





FIG. 33

is a side elevational, partially broken away view of an internal portion of the circuit interrupter showing the handle assembly, sideplate assembly, and crossbar assembly with associated stop members.





FIG. 34A

is an orthogonal view of the handle of the operating mechanism of the circuit interrupter shown in FIG.


1


.





FIG. 34B

is a side elevational view of the handle of FIG.


34


A.





FIG. 34C

is another orthogonal view of the handle of FIG.


34


A.





FIG. 34D

is an underneath view of the handle of FIG.


34


A.





FIG. 35

is an orthogonal view of the handle slider of the operating mechanism of the circuit interrupter shown in FIG.


1


.





FIG. 36

is an exploded, partially broken away view of the cover, handle, and handle slider of the circuit interrupter of FIG.


1


.





FIG. 37

is an orthogonal, partially broken away view similar to

FIG. 36

showing the engagement of the handle with the handle slider and the cover.





FIG. 38

is another orthogonal view of the handle of

FIG. 34A

showing the grooves for the handle slider.





FIG. 39

is an exploded, profile view of the base and the cover of the circuit interrupter of FIG.


1


.





FIG. 40

is a cross-sectional view of the cover secured to the base, taken along the line


40





40


of FIG.


1


.





FIG. 41

is an orthogonal view of the attaching device used to secure the cover to the base.





FIG. 42

is an exploded view of the cover and the base of the circuit interrupter of FIG.


1


and the support members thereof.





FIG. 43

is an overhead view of the base showing the slots and grooves therein associated with the support members shown in FIG.


42


.





FIG. 44A

is an orthogonal view of one of the support members shown in FIG.


42


.





FIG. 44B

is an overhead view of the support member shown in FIG.


44


A.





FIG. 45A

is an orthogonal view of the other support member shown in FIG.


42


.





FIG. 45B

is another orthogonal view of the support member shown in FIG.


45


A.





FIG. 45C

is an overhead view of the support member shown in FIG.


45


A.





FIG. 46

is an orthogonal view of the base and internal portions of the circuit interrupter of

FIG. 1

showing the positioning of the support members.





FIG. 47A

is an orthogonal view of the deflector used in connection with the self-retaining collar of the line terminal of the circuit interrupter of FIG.


1


.





FIG. 47B

is another orthogonal view of the deflector shown in FIG.


47


A.





FIG. 48

is an orthogonal view of the internal portions of the circuit interrupter of

FIG. 1

without the arc extinguisher assembly.





FIG. 49

is another orthogonal view similar to

FIG. 48

but also showing the positioning of the deflector.





FIG. 50

is an exploded view of the base and cover of the circuit interrupter of

FIG. 1

again showing the positioning of the deflector.





FIG. 51

is an orthogonal view of a lug assembly that may be implemented with the circuit interrupter of FIG.


1


and the lug insulator associated therewith.





FIG. 52

is an orthogonal view of the lug insulator shown in FIG.


51


.





FIG. 53

is an orthogonal view of the lug assembly and lug insulator of

FIG. 51

in an assembled state.





FIG. 54

is an orthogonal view of the circuit interrupter of

FIG. 1

with the lug assembly and lug insulator attached.











DESCRIPTION OF THE PREFERRED EMBODIMENT




Referring now to the drawings and

FIGS. 1 and 2

in particular, shown is a molded case circuit breaker


10


. Circuit breaker


10


includes a base


12


mechanically interconnected with a cover


14


to form a circuit breaker housing


15


. Holes or openings


16


(

FIG. 2

) are provided in cover


14


for accepting screws or other attaching devices


128


that enter corresponding holes or openings


18


in base


12


for fastening cover


14


to base


12


. Holes


20


, which feed through cover


14


, are provided for internal access to circuit breaker


10


, as described in greater detail below. At the interface between base


12


and cover


14


are small openings


21


for venting purposes, as described in greater detail below. Cover


14


includes a handle opening


22


through which protrudes a handle


24


(

FIG. 1

) that is used in a conventional manner to manually open and close the contacts of circuit breaker


10


and to reset circuit breaker


10


when it is in a tripped state. Handle


24


may also provide an indication of the status of circuit breaker


10


whereby the position of handle


24


corresponds with a legend (not shown) on cover


14


near handle opening


22


which clearly indicates whether circuit breaker


10


is ON (contacts closed), OFF (contacts open), or TRIPPED (contacts open due to, for example, an overcurrent condition). Cover


14


also includes a rectangular opening


23


(

FIG. 2

) through which protrudes a top portion


25


A of a button for a push-to-trip actuator, the details of which are described below. Also shown is a load conductor opening


26


in base


12


that shields and protects a load terminal (not shown). Although circuit breaker


10


is depicted as a single-phase circuit breaker, the present invention is not limited to single-phase operation.




Referring now to

FIG. 3

, a longitudinal section of a side elevation, partially broken away and partially in phantom, of circuit breaker


10


is shown having a load terminal


28


and a line terminal


29


. There is shown a plasma arc acceleration chamber


30


comprising a slot motor assembly


32


and an arc extinguisher assembly


34


. Also shown is a contact assembly


36


, an operating mechanism


38


, and a trip mechanism


40


.




Referring again to

FIG. 3

, and now also to

FIG. 4

which shows a side elevational view of the internal workings of circuit breaker


10


without base


12


and cover


14


, slot motor assembly


32


is shown as including a separate upper slot motor assembly


32


A and a separate lower slot motor assembly


32


B. Upper slot motor assembly


32


A includes an upper slot motor assembly housing


41


within which are stacked side-by-side U-shaped upper slot motor assembly plates


42


. Similarly, lower slot motor assembly


32


B includes a lower slot motor assembly housing


43


within which are stacked side-by-side lower slot motor assembly plates


44


. Plates


42


and


44


are both composed of magnetic material.




Arc extinguisher assembly


34


includes an arc chute


46


within which are positioned spaced-apart generally parallel angularly offset arc chute plates


48


and an upper arc runner


48


A. As known to one of ordinary skill in the art, the function of arc extinguisher assembly


34


is to receive and dissipate electrical arcs that are created upon separation of the contacts of the circuit breaker.




Referring now to

FIG. 5

, shown is an orthogonal view of an internal portion of circuit breaker


10


. There is shown contact assembly


36


comprising a movable contact arm


50


supporting thereon a movable contact


52


, and a stationary contact arm


54


supporting thereon a stationary contact


56


. Stationary contact arm


54


is electrically connected to line terminal


29


and, as discussed below, movable contact arm


50


is electrically connected to load terminal


28


. Also shown is a crossbar assembly


60


which traverses the width of circuit breaker


10


and is rotatably disposed on an internal portion of base


12


(not shown). Actuation of operating mechanism


38


, in a manner described in detail below, causes crossbar assembly


60


and movable contact arm


50


to rotate into or out of a disposition which places movable contact


52


into or out of a disposition of electrical continuity with fixed contact


56


. Crossbar assembly


60


includes a movable contact cam housing


62


in which is disposed a pivot pin


64


upon which movable contact arm


50


is rotatably disposed. Under normal circumstances, movable contact arm


50


rotates in unison with the rotation of housing


62


as housing


62


is rotated clockwise or counter-clockwise by action of operating mechanism


38


. However, it is to be noted that movable contact arm


50


is free to rotate (within limits) independently of the rotation of crossbar assembly


60


. In particular, in certain dynamic, electro-magnetic situations, movable contact arm


50


can rotate upwardly about pivot pin


64


under the influence of high magnetic forces. This is referred to as “blow-open” operation, and is described in greater detail below.




Continuing to refer to FIG.


5


and again to

FIG. 3

, operating mechanism


38


is shown. Operating mechanism


38


is structurally and functionally similar to that shown and described in U.S. patent No. 4,503,408 issued Mar. 5, 1985 to Mrenna et al, and U.S. patent 5,910,760 issued Jun. 8, 1999, both disclosures of which are incorporated herein by reference. Operating mechanism


38


comprises a handle arm or handle assembly


70


(connected to handle


24


), a configured plate or cradle


72


, an upper toggle link


74


, an interlinked lower toggle link


76


, and an upper toggle link pivot pin


78


which interlinks upper toggle link


74


with cradle


72


. Lower toggle link


76


is pivotally interconnected with upper toggle link


74


by way of an intermediate toggle link pivot pin


80


, and with crossbar assembly


60


at pivot pin


64


. Provided is a cradle pivot pin


82


which is laterally and rotatably disposed between parallel, spaced apart operating mechanism support members or sideplates


84


. Cradle


72


is free to rotate (within limits) via cradle pivot pin


82


. Also provided is a handle assembly roller


86


which is disposed in and supported by handle assembly


70


in such a manner as to make mechanical contact with (roll against) arcuate portions of a back region


87


of cradle


72


during a “resetting” operation of circuit breaker


10


as is described below. A main stop bar


88


is laterally disposed between sideplates


84


, and provides a limit to the counter-clockwise movement of cradle


72


.




Referring now to

FIG. 6

, an elevation of that part of circuit breaker


10


particular associated with operating mechanism


38


is shown for the OFF disposition of circuit breaker


10


. Contacts


52


and


56


are shown in the disconnected or open disposition. An intermediate latch


90


is shown in its latched position wherein it abuts hard against a lower portion


92


of a latch cutout region


94


of cradle


72


. A pair of side-by-side aligned compression springs (not shown) such as shown in U.S. Pat. No. 4,503,408 is disposed between the top portion of handle assembly


70


and the intermediate toggle link pivot pin


80


. The tension in these springs has a tendency to load lower portion


92


of cradle


72


against the intermediate latch


90


. In the OPEN disposition shown in

FIG. 6

, latch


90


is prevented from unlatching cradle


72


, notwithstanding the spring tension, because the other end thereof is fixed in place by a rotatable trip bar assembly


190


of trip mechanism


40


. As is described in more detail below, trip bar assembly


190


is spring-biased in the counter-clockwise rotational direction against the intermediate latch


90


. This is the standard latch arrangement found in all dispositions of circuit breaker


10


except the TRIPPED disposition which is described below.




Referring now to

FIG. 7

, operating mechanism


38


is shown for the ON disposition of circuit breaker


10


. In this disposition, contacts


52


and


56


are closed (in contact with each other) whereby electrical current may flow from load terminal


28


to line terminal


29


. In order to achieve the ON disposition, handle


24


, and thus fixedly attached handle assembly


70


, are rotated in a counter-clockwise direction (to the left) thus causing the intermediate toggle link pivot pin


80


to be influenced by the tension springs (not shown) attached thereto and to the top of handle assembly


70


. The influence of the tension springs causes upper toggle link


74


and lower toggle link


76


to assume the position shown in

FIG. 7

which causes the pivotal interconnection with crossbar assembly


60


at pivot point


64


to rotate crossbar assembly


60


in the counter-clockwise direction. This rotation of crossbar assembly


60


causes movable contact arm


50


to rotate in the counter-clockwise direction and ultimately force movable contact


52


into a pressurized abutted disposition with stationary contact


56


. It is to be noted that cradle


72


remains latched by intermediate latch


90


as influenced by trip mechanism


40


.




Referring now to

FIG. 8

, operating mechanism


38


is shown for the TRIPPED disposition of circuit breaker


10


. The TRIPPED disposition is related (except when a manual tripping operation is performed, as described below) to an automatic opening of circuit breaker


10


caused by the thermally or magnetically induced reaction of trip mechanism


40


to the magnitude of the current flowing between load conductor


28


and line conductor


29


. The operation of trip mechanism


40


is described in detail below. For purposes here, circumstances such as a load current with a magnitude exceeding a predetermined threshold will cause trip mechanism


40


to rotate trip bar assembly


190


clockwise (overcoming the spring force biasing assembly


190


in the opposite direction) and away from intermediate latch


90


. This unlocking of latch


90


releases cradle


72


(which had been held in place at lower portion


92


of latch cutout region


94


) and enables it to be rotated counter-clockwise under the influence of the tension springs (not shown) interacting between the top of handle assembly


70


and the intermediate toggle link pivot pin


80


. The resulting collapse of the toggle arrangement causes pivot pin


64


to be rotated clockwise and upwardly to thus cause crossbar assembly


60


to similarly rotate. This rotation of crossbar assembly


60


causes a clockwise motion of movable contact arm


50


, resulting in a separation of contacts


52


and


56


. The above sequence of events results in handle


24


being placed into an intermediate disposition between its OFF disposition (as shown in

FIG. 6

) and its ON disposition (as shown in FIG.


7


). Once in this TRIPPED disposition, circuit breaker


10


can not again achieve the ON disposition (contacts


52


and


56


closed) until it is first “reset” via a resetting operation which is described in detail below.




Referring now to

FIG. 9

, operating mechanism


38


is shown during the resetting operation of circuit breaker


10


. This occurs while contacts


52


and


56


remain open, and is exemplified by a forceful movement of handle


24


to the right (or in a clockwise direction) after a tripping operation has occurred as described above with respect to FIG.


8


. As handle


24


is thus moved, handle assembly


70


moves correspondingly, causing handle assembly roller


86


to make contact with back region


87


of cradle


72


. This contact forces cradle


72


to rotate clockwise about cradle pivot pin


82


and against the tension of the springs (not shown) that are located between the top of handle assembly


70


and the intermediate toggle link pivot pin


80


, until an upper portion


93


of latch cutout region


94


abuts against the upper arm or end of intermediate latch


90


. This abutment forces intermediate latch


90


to rotate to the left (or in a counter-clockwise direction) so that the bottom portion thereof rotates to a disposition of interlatching with trip bar assembly


190


, in a manner described in more detail below. Then, when the force against handle


24


is released, handle


24


rotates to the left over a small angular increment, causing lower portion


92


of latch cutout region


94


to forcefully abut against intermediate latch


90


which is now abutted at its lower end against trip bar assembly


190


. Circuit breaker


10


is then in the OFF disposition shown in

FIG. 6

, and handle


24


may then be moved counter-clockwise (to the left) towards the ON disposition depicted in

FIG. 7

(without the latching arrangement being disturbed) until contacts


52


and


56


are in a disposition of forceful electrical contact with each other. However, if an overcurrent condition still exists, a tripping operation such as depicted and described above with respect to

FIG. 8

may again take place causing contacts


52


and


56


to again open.




Referring again to

FIGS. 3

,


4


, and


5


, upper slot motor assembly


32


A and lower slot motor assembly


32


B are structurally and functionally similar to that described in U.S. patent No. 5,910,760 and plates


42


and


44


thereof form an essentially closed electromagnetic path in the viscinity of contacts


52


and


56


. At the beginning of a contact opening operation, electrical current continues to flow in movable contact arm


50


and through an electrical arc created between contacts


52


and


56


. This current induces a magnetic field into the closed magnetic loop provided by upper plates


42


and lower plates


44


of upper slot motor assembly


32


A and lower slot motor assembly


32


B, respectively. This magnetic field electromagnetically interacts with the current in such a manner as to accelerate the movement of movable contact arm


50


in the opening direction whereby contacts


52


and


56


are more rapidly separated. The higher the magnitude of the electrical current flowing in the arc, the stronger the magnetic interaction and the more quickly contacts


52


and


56


separate. For very high current (an overcurrent condition), the above process provides the blow-open operation described above in which movable contact arm


50


forcefully rotates upwardly about pivot pin


64


and separates contacts


52


and


56


, this rotation being independent of crossbar assembly


60


. This blow-open operation is shown and described in U.S. patent No. 3,815,059 issued Jun. 4, 1974, to Spoelman and incorporated herein by reference, and provides a faster separation of contacts


52


and


56


than can normally occur as the result of a tripping operation generated by trip mechanism


40


as described above in connection with FIG.


8


.




In connection with the above-described blow-open operation, crossbar assembly


60


and, in particular, cam housing


62


are structurally and functionally similar to that described in U.S. patent No. 5,910,760. In particular, cam housing


62


includes a spring-loaded cam follower (not shown) which, when a blow-open opeation has occurred, latches movable contact arm


50


in its blown-open disposition.




Referring now to

FIGS. 10A

,


10


B,


10


C,


10


D,


10


E, and


10


F, shown is integrally molded trip bar assembly


190


of trip mechanism


40


. Assembly


190


includes a trip shaft


192


to which is connected a thermal trip bar or paddle


194


, a magnetic trip bar or paddle


196


, and a manual trip bar


198


, the function of each of which is described in detail below. Assembly


190


also includes an intermediate latch interface


200


having a protrusion or stepped-up region


201


and a cutout region or stepped-down region


203


with a surface


203


A. Near one end of trip shaft


192


is a channel or groove


199


that partially extends around the circumference thereof. As shown in

FIG. 10C

, groove


199


has an end


199


A on the underside of trip shaft


192


that defines a cavity extending into shaft


192


. Assembly


190


also includes a torsion spring


202


, as shown in

FIG. 10D

, having an elbow


202


A defining an end


202


B, and an end


202


C. As shown in

FIGS. 10E and 10F

, spring


202


is wound around the end of trip shaft


192


, and is partially seated within groove


199


. Elbow


202


A of spring


202


is shown positioned at end


199


A of groove


199


, with end


202


B of spring


202


inserted into the cavity. Groove


199


serves to properly position spring


202


and prevent dislodgment thereof from shaft


192


. In a preferred embodiment wherein spring


202


is approximately 0.018 inches in diameter, groove


199


is approximately 0.030 inches in width and approximately 0.015 inches deep.




Referring now to

FIG. 11

, shown is intermediate latch


90


. Latch


90


includes a main member


206


having ends


207


which are bent towards each other and in which are formed holes or openings


208


. Extending from main member


206


is an upper latch portion


210


and a lower latch portion


212


, the latch portions being linearly offset from each other in the exemplary embodiment. Lower latch portion


212


includes a protruding region


213


with a bottom surface


213


A, and a cutout region


214


.




Referring now also to

FIGS. 12

,


13


, and


14


, shown is trip bar assembly


190


in conjunction with a portion of the internal workings of circuit breaker


10


. Trip shaft


192


is shown laterally disposed between parallel sideplates


84


of the sideplate assembly, with its ends positioned within holes or openings


216


. This disposition provides a pivot area about which trip bar assembly


190


can rotate. This rotation is influenced by spring


202


that rotationally biases assembly


190


in the counter-clockwise direction. Also shown is intermediate latch


90


which, like trip shaft


192


, is laterally disposed between sideplates


84


. Holes or openings


208


of latch


90


are mated with corresponding circular protrusions or indents


218


in sideplates


84


, providing a pivot area for rotation of latch


90


. Protrusions or indents


220


in sideplates


84


provide a stop for limiting the rotation of latch


90


in the clockwise direction which occurs during a tripping operation as described below.





FIG. 12

shows the latching arrangement found in all dispositions of circuit breaker


10


except the TRIPPED disposition. Lower latch portion


212


of latch


90


is shown fixed in place by intermediate latch interface


200


of trip bar assembly


190


. In particular, as also seen in

FIG. 14

, cutout region


214


of latch


90


is shown mated with protrusion


201


of interface


200


, with bottom surface


213


A of protruding region


213


of latch


90


in an abutted, engaged relationship with surface


203


A of interface


200


. Upper latch portion


210


of latch


90


is shown abutted hard against lower portion


92


of latch cutout region


94


of cradle


72


. Because latch


90


is prevented from clockwise rotation due to the engagement of lower latch portion


212


with intermediate latch interface


200


, the abutment of upper latch portion


210


with cradle


72


prevents the counter-clockwise rotation of cradle


72


, notwithstanding the spring tension (described above) experienced by the cradle in that direction. However, during a tripping operation as described below, trip bar assembly


190


is rotated clockwise (overcoming the spring tension provided by spring


202


), causing surface


203


A of intermediate latch interface


200


to rotate away from its abutted, engaged relationship with protruding region


213


of intermediate latch


90


. This disengagement enables the spring forces experienced by cradle


72


to rotate latch


90


in a clockwise direction, thereby terminating the hard abutment between upper latch portion


210


and cradle


72


, and releasing the cradle to be rotated counter-clockwise by the aforementioned springs until operating mechanism


38


is in the TRIPPED disposition described above in connection with FIG.


8


.




In the preferred exemplary embodiment, protrusion


201


of interface


200


has a height


201


A (

FIG. 10B

) that exceeds height


214


A (

FIG. 11

) of cutout regions


214


. In one embodiment, height


201


A is approximately twice that of height


214


A. This preferred configuration prevents improper engagement of latch portion


212


with interface


200


due to any over-rotation of latch


90


in the counter-clockwise direction during the resetting operation described above with respect to FIG.


9


. In particular, it prevents the bottom surface of latch portion


212


near cutout region


214


from improperly contacting and abutting top surface


201


B (

FIG. 10B

) of protrusion


201


which would keep bottom surface


213


A (

FIG. 11

) of protruding region


213


floating (disengaged) and undesirably alter the latch load relationship of trip mechanism


40


.




As shown in

FIG. 14

, spring


202


is positioned in channel


199


of trip shaft


192


with end


202


C of spring


202


rotated counter-clockwise (shown with dashed lines) from its vertical position (shown with solid lines) and positioned under and in pressurized contact with intermediate latch


90


. In particular, end


202


C is positioned under and in pressurized contact with an undersurface


209


A of an elbow area


209


(

FIG. 11

) of latch


90


. Positioned as such, end


202


C of spring


202


applies a bias force to latch


90


in the counter-clockwise rotational direction, for reasons discussed below. The configuration, size, and positioning of spring


202


is chosen so that the bias force provided by end


202


C is, at all times, smaller in magnitude than the spring forces experienced by cradle


72


, thereby always enabling the cradle spring forces to rotate latch


90


in a clockwise direction (as described above) when latch


90


and latch interface


200


are disengaged due to a tripping operation. When latch


90


has been rotated clockwise due to a tripping operation as such, the cradle spring forces are no longer felt by latch


90


after cradle


72


has rotated counter-clockwise and lower portion


92


of latch cutout region


94


no longer contacts latch


90


. The bias force provided by end


202


C of spring


202


then takes over and rotates latch


90


in the counter-clockwise direction. The configuration, size, and positioning of spring


202


is chosen so that the bias force rotates latch


90


in the counter-clockwise direction only to a point where upper latch portion


210


is properly positioned to make contact with upper portion


93


of latch cutout region


94


during the resetting operation described above with respect to FIG.


9


. The counter-clockwise rotation of latch


90


due to end


202


C of spring


202


advantageously prevents upper latch portion


210


from being left in a clockwise over-rotated position (due to the cradle spring forces) where latch portion


210


is in too vertical of a position such that, during the resetting operation, it could undesirably contact upper portion


93


of latch cutout region


94


at an angle that would prevent or make it difficult for latch


90


to be rotated counter-clockwise (this rotation being necessary for lower latch portion


212


to become latched with latch interface


200


, as described above).




As described above, protrusions or stops


220


are provided in sideplates


84


in order to limit the clockwise rotation of latch


90


. Although these protrusions ideally prevent clockwise over-rotation of latch


90


into too vertical of a position, variability in parts may limit their ability to accomplish this goal. By supplying a constant bias force on latch


90


in the counter-clockwise direction, end


202


C of spring


202


cooperates with stops


220


to ensure that the desired over-rotation protection exists.




There are several types of tripping operations that can cause trip bar assembly


190


to rotate in the clockwise direction and thereby release cradle


72


. One type is a manual tripping operation, and the structure associated therewith is shown in FIG.


15


.

FIG. 15

shows a portion of the internal workings of circuit breaker


10


within base


12


, with base


12


having been cut away at


226


A and


226


B to provide a better view thereof. Shown is trip bar assembly


190


and manual trip bar


198


thereof. Along the outer sidewall of base


12


is a push-to-trip actuator


230


of trip mechanism


40


that is positioned such that it can be moved upwardly or downwardly. Actuator


230


includes a button


25


with a top portion


25


A that protrudes through rectangular opening


23


of cover


14


(FIGS.


1


-


2


).




Referring now also to

FIGS. 16A and 16B

, push-to-trip actuator


230


is comprised of a main bar-like member


231


that slightly tapers near its bottom


232


where it slideably fits into a groove formed between housing structures


228


A,


228


B, and


229


and the outer sidewall of base


12


(FIG.


15


). This groove provides a guide for the vertical motion of push-to-trip actuator


230


. Actuator


230


includes a stop member


235


that is positioned to abut housing structure


229


in order to limit the downward movement of actuator


230


within this groove. For reasons discussed below, a spring (not shown) is seated between bottom


232


of actuator


230


and the bottom of base


12


. Near its top, actuator


230


includes shoulders


233


from which upwardly protrudes a curved flange


234


. Button


25


sits upon shoulders


233


and, as shown in

FIG. 17

, includes an appropriately configured opening


236


into which curved flange


234


is inserted. Button


25


also includes a shoulder


237


which abuts upwardly against a bottom surface of cover


14


so as to limit the upward vertical movement of push-to-trip actuator


230


, and a cut-out section


238


for providing clearance for handle


24


and its associated handle slider, as described in greater detail below. Protruding outwardly from approximately the middle of main member


231


of push-to-trip actuator


230


is a downwardly curved arm


240


with a bottom portion


242


. As shown in

FIG. 15

, bottom portion


242


of arm


240


is positioned just above manual trip bar


198


of trip bar assembly


190


.




When top portion


25


A of button


25


is depressed, the resulting downward movement of push-to-trip actuator


230


causes bottom portion


242


of arm


240


to contact manual trip bar or member


198


, thereby causing trip bar assembly


190


to rotate in the clockwise direction. As described above, this rotation of assembly


190


releases cradle


72


and results in the TRIPPED disposition shown in FIG.


8


. The spring (not shown) positioned below bottom


232


of push-to-trip actuator


230


causes the actuator to return to its initial position when force upon top portion


25


A of button


25


is no longer exerted.




In a preferred embodiment, push-to-trip actuator


230


(except button


25


) is comprised of a metal such as carbon steel, and is integrally formed via a stamping process. As such, the strength of the main portion of actuator


230


is enhanced, enabling it to have thinner dimensions which are highly desirable in view of the space constraints of modern circuit breakers such as circuit breaker


10


. In the exemplary embodiment, the carbon steel of actuator


230


is 0.045 inches thick. Button


25


is preferably comprised of a suitable polymer (plastic) with electrical insulating properties.




In addition to the manual tripping operation described above, circuit breaker


10


includes automatic thermal and magnetic tripping operations which likewise can cause trip bar assembly


190


to rotate in the clockwise direction and thereby release cradle


72


. The structure for providing these additional tripping operations can be seen in

FIG. 7

which shows circuit breaker


10


in its ON (non-TRIPPED) disposition, with latch


90


abutted hard against lower portion


92


of latch cutout region


94


of cradle


72


, and latch


90


held in place by intermediate latch interface


200


(

FIG. 10B

) of trip bar assembly


190


. Also shown is an automatic trip assembly


250


of trip mechanism


40


that is positioned in close proximity to trip bar assembly


190


.




Referring now also to

FIGS. 18A

,


18


B,


18


C,


19


A,


19


B,


20


,


21


,


22


A, and


22


B, shown in isolation is automatic trip assembly


250


and its various components. Assembly


250


includes a magnetic yoke


252


, a bimetal


254


, a magnetic clapper or armature


256


, and load terminal


28


. Magnetic yoke


252


(

FIGS. 19A and 19B

) includes a substantially planar portion


258


with a bottom portion


258


A. Protruding from portion


258


are curved arms or wings


260


and


262


having front faces


260


A and


262


A. At the tops of arms


260


and


262


are pivot supports


264


and


266


, with respective pivot surfaces


268


and


270


on which pivot magnetic clapper


256


, as described below. Pivot support


264


includes a front retaining ridge or raised surface


263


that helps define pivot surface


268


, and pivot support


266


includes a downwardly facing stop or protrusion


265


. Pivot supports


264


and


266


each include a rear retaining protrusion


267


which helps define pivot surfaces


268


and


270


. Yoke


252


also includes a shoulder portion


272


above which is positioned a portion of load terminal


28


, as described below. In addition, holes or openings


274


are formed through substantially planar portion


258


for purposes described below. Yoke


252


of the exemplary embodiment is made of carbon steel material of approximately 0.078 inch thickness.




Bimetal


254


(

FIG. 20

) is planar and substantially rectangular in form and includes two cutout regions


280


and


282


forming a neck


284


upon which sits a head portion


286


. Through a bottom portion


287


of bimetal


254


is a hole or opening


288


for purposes described below. Bimetal


254


is structured as is known to one of skill in the art such that bottom portion


287


deflects (bends) in a conventional manner above certain temperatures.




Magnetic clapper


256


(

FIG. 21

) is planar in form and includes cutout regions


312


and


314


which form shoulders


313


and


315


, a neck portion


311


, and a head portion


316


. Head portion


316


includes horizontal pivot portions or arms


318


, and the outside corner of shoulder


315


includes a chamfered region or cutout


317


. The body of clapper


256


is wider than the body of magnetic yoke


252


, with distance d


2


greater than distance d


1


(FIG.


19


B). Clapper


256


includes holes or openings


320


formed within a bottom portion


319


for purposes described below, and is formed of carbon steel material in the exemplary embodiment.




Load terminal


28


(

FIGS. 22A and 22B

) includes a substantially planar portion


290


from which protrudes, in approximately perpendicular fashion, a bottom connector portion


292


that connects with an external input of electrical current by means of a connecting device such as a self-retaining collar. Such a collar provides both a physical and electrical connection, and an example collar


295


is shown in

FIG. 4

(connected to connector portion


292


as well as to a similar portion of line terminal


29


) and is described in greater detail below in connection with FIG.


29


. For purposes described below with respect to

FIG. 29

, connector portion


292


has a hole or opening


294


, raised portions or surfaces


297


on the top thereof, and cut-outs


299


that cause front face


301


to have a smaller width than the rest of connector


292


. Located at the other end of terminal


28


is a top substantially planar region


296


which is offset from portion


290


via a curved region


298


. Formed through portion


290


are holes or openings


300


,


302


, and


304


. A tab or protrusion


306


protrudes from one side of portion


290


near hole


304


. Planar portion


290


includes offsets or ribbed portions


308


formed along the sides thereof. As best seen in

FIG. 22A

, planar portion


290


slightly tapers along its length in a gradual manner, with width w


2


wider than width w


1


.




Referring briefly now also to

FIGS. 23-27

, shown in

FIG. 23

is a portion of base


12


into which load terminal


28


mounts when assembled into circuit breaker


10


. Base


12


includes channels


520


formed in both sides thereof, each with a bottom


522


. As shown in

FIG. 24

, the sides of planar portion


290


of load terminal


28


, and in particular ribbed portions


308


, insert into channels


520


until bottom shoulders


291


(see

FIG. 22B

) of terminal


28


abut the bottoms


522


of channels


520


. Inserted as such, with an interference fit provided by ribs


308


, lateral movement of terminal


28


relative to base


12


is prevented. The sides of base


12


, and therefore channels


520


formed therein, are slightly tapered from top to bottom, as best shown in

FIG. 25

, with distance d


2


greater than distance dl. This tapering aids in the molded production of base


12


. The tapering of planar portion


290


of terminal


28


follows this tapering of base


12


so as to provide a snug fit therewith upon insertion. Ribbed portions


308


enhance the frictional engagement between terminal


28


and channels


520


, thereby also resisting vertical movement of terminal


28


relative to base


12


. In order to further prevent vertical movement of terminal


28


relative to base


12


, cover


14


includes an abutment portion or wall


525


, as shown in

FIGS. 26 and 27

, having a bottom that is appropriately positioned and dimensioned to abut protrusion


306


of terminal


28


when cover


14


is in a position of securement with base


12


. This abutment holds protrusion


306


down, thus keeping terminal


28


fully seated in channels


520


. In the exemplary embodiment, the bottom of abutment wall


525


includes a contact member or crush rib


526


that is positioned to directly contact protrusion


306


when cover


14


is secured to base


12


. Rib


526


is formed of compressible material, thereby providing a little “give” to the abutment of wall


525


with protrusion


306


and ensuring proper fit notwithstanding slight variability in the circuit breaker components in issue. In one embodiment, crush rib


526


is formed of a thermoset glass polyester material like the rest of cover


14


but with a reduced amount of fiberglass in order to provide enhanced compressibility.





FIGS. 18A and 18B

show automatic trip assembly


250


in assembled form. Neck


284


of bimetal


254


is positioned between arms


260


and


262


of yoke


252


whereby bimetal


254


is substantially parallel (but not in contact) with portion


258


of yoke


252


. A screw


255


is shown partially screwed into one side of opening


288


in bottom portion


287


of bimetal


254


, for reasons discussed below. Head portion


286


of bimetal


254


is connected to top region


296


of load terminal


28


by way of a conventional heat welding or brazing process. Curved region


298


of load terminal


28


is positioned above shoulder


272


of yoke


252


, with planar portion


290


of terminal


28


parallel and in contact with planar portion


258


of yoke


252


. Securing terminal


28


to yoke


252


are securing devices such as rivets


330


which are inserted into holes


274


of yoke


252


and corresponding holes


300


of terminal


28


. Secured in this manner, terminal


28


advantageously has only one heat-affected zone which is in the area of top region


296


. Positioned in contact with (seated in) pivot surfaces


268


and


270


of yoke


252


are pivot arms


318


of magnetic armature


256


for providing a limited range of motion of clapper


256


, as discussed in more detail below. As seen in

FIG. 18C

, chamfered region or cutout


317


of armature


256


facilitates this positioning of the armature during the assembly process. Armature


256


is first tilted (as shown) with cutout


317


positioned below pivot support


266


and stop


265


thereof. Cutout


317


provides clearance that enables arm


318


above cutout region


314


to then be rotated into contact with pivot surface


270


. Arm


318


above cutout region


312


can then be easily swung over the end of pivot support


264


and into contact with pivot surface


268


. During operation of circuit breaker


10


, pivot arms


318


are maintained in contact with pivot surfaces


268


and


270


by way of retaining member


263


and retaining protrusions


267


of yoke


252


. Two springs


253


(only one is clearly shown) are attached to and disposed between holes


320


of clapper


256


and holes


302


of terminal


28


, with curved ends or hooks


253


A of springs


253


protruding through the holes and providing the attachment. Springs


253


have a tendency to maintain a predetermined distance between bottom portion


319


of magnetic clapper


256


and front faces


260


A and


262


A of magnetic yoke


252


, and to maintain clapper


256


in a position that is rotationally displaced in a clockwise manner from vertical (away from yoke


252


). As seen in

FIG. 18A

, stop or protrusion


265


of pivot support


266


is positioned to make contact with a clockwise rotated clapper


256


(near shoulder


315


), defining a maximum angle of rotational displacement of clapper


256


.




When implemented in circuit breaker


10


as shown in

FIG. 7

, automatic trip assembly


250


operates to cause a clockwise rotation of trip bar assembly


190


, thereby releasing cradle


72


which leads to the TRIPPED disposition described above in connection with

FIG. 8

, whenever overcurrent conditions exist in the ON disposition. In the ON disposition as shown in

FIG. 7

, electrical current flows (in the following or opposite direction) from load terminal


28


, through magnetic yoke


252


and bimetal


254


, from bottom portion


287


of bimetal


254


to movable contact arm


50


through a conductive cord


289


(shown in

FIG. 3

) that is welded therebetween, through closed contacts


52


and


56


, and from stationary contact arm


54


to line terminal


29


. Automatic trip assembly


250


reacts to an undesirably high amount of electrical current flowing through it, providing both a thermal and a magnetic tripping operation.




The thermal tripping operation of automatic trip assembly


250


is attributable to the reaction of bimetal


254


to current flowing therethrough. The temperature of bimetal


254


is proportional to the magnitude of the electrical current. As current magnitude increases, the heat buildup in bimetal


254


has a tendency to cause bottom portion


287


to deflect (bend) to the left (as viewed in FIG.


7


). When non-overcurrent conditions exist, this deflection is minimal. However, above a predetermined current level, the temperature of bimetal


254


will exceed a threshold temperature whereby the deflection of bimetal


254


causes bottom portion


287


to make contact with thermal trip bar or member


194


of trip bar assembly


190


. This contact forces assembly


190


to rotate in the clockwise direction, thereby releasing cradle


72


which leads to the TRIPPED disposition. The predetermined current level (overcurrent) that causes this thermal tripping operation can be adjusted in a conventional manner by changing the size and/or shape of bimetal


254


. Furthermore, adjustment can be made by selectively screwing screw


255


(FIG.


18


A - - - not shown in

FIG. 7

) farther into opening


288


such that it protrudes to a certain extent through the other side of bimetal


254


(towards thermal trip member


194


). Protruding as such, screw


255


is positioned to more readily contact thermal trip member


194


(and thus rotate assembly


190


) when bimetal


254


deflects, thus selectively reducing the amount of deflection that is necessary to cause the thermal tripping operation.




Cutout regions


280


and


282


of bimetal


254


have rounded corners


280


A and


282


A (FIG.


20


), respectively, which ease and facilitate the higher density downward current flow in those regions (during the ON disposition of circuit breaker


10


) caused by the narrowing of the flow path of current between head portion


286


and neck


284


. In an assembled automatic trip assembly


250


, cutout region


282


extends down the length of bimetal


254


substantially past the bottom of arms


260


and


262


of magnetic yoke


252


(see

FIG. 18A

) in order to prevent interference with other internal and/or housing components positioned in close proximity thereto. In contrast, cutout region


280


extends to a point approximately just below the bottom of arms


260


and


262


. This provides for a wider bimetal


254


below arms


260


and


262


of magnetic yoke


252


which reduces the susceptibility of those portions of bimetal


254


to increased eddy current effect heating that could cause an annealing or pitting of that area during high (interrupt) current conditions.




Automatic trip assembly


250


also provides a magnetic tripping operation. As electrical current flows through magnetic yoke


252


, a magnetic field is created having a strength that is proportional to the magnitude of the current. This magnetic field generates an attractive force that has a tendency to pull magnetic clapper


256


towards front faces


260


A and


262


A of yoke


252


. The magnitude of this attractive force is enhanced because, as described above, the body of clapper


256


is wider than the body of yoke


252


. When non-overcurrent conditions exist, the tension provided by springs


253


connected between holes


320


of clapper


256


and holes


302


of load terminal


28


prevent any substantial rotation of clapper


256


. However, above a predetermined current level, a threshold level magnetic field is created that overcomes the spring tension, compressing springs


253


and enabling bottom portion


319


of clapper


256


to forcefully rotate counter-clockwise towards front faces


260


A and


262


A of yoke


252


. During this rotation, bottom portion


319


of clapper


256


makes contact with magnetic trip bar or member


196


which, as shown in

FIG. 7

, is partially positioned between clapper


256


and front faces


260


A and


262


A of yoke


252


. This contact moves the end of trip bar


196


substantially between curved arms


260


and


262


of yoke


252


, thereby forcing trip bar assembly


190


to rotate in the clockwise direction. This leads to the TRIPPED disposition as described in detail above in connection with FIG.


8


. As with the thermal tripping operation, the predetermined current level that causes this magnetic tripping operation can be adjusted. Adjustment may be accomplished by implementation of different sized or tensioned springs


253


that are connected between bottom portion


319


of clapper


256


and load terminal


28


.




In

FIGS. 7

,


18


A, and


18


B, it can be seen that portions


258


and


258


A of magnetic yoke


252


substantially extend between bimetal


254


and load terminal


28


. This positioning of metallic magnetic yoke


252


causes a general reshaping of the magnetic flux lines that are generated by the oppositely flowing currents in terminal


28


and bimetal


254


during the ON disposition of circuit breaker


10


. By reshaping the flux lines, this configuration limits the interference between the flux lines, thereby reducing the outward blowoff force between terminal


28


and bimetal


254


that is generated during high (interrupt) current conditions. This reduction in blowoff force reduces the likelihood of the force causing terminal


28


and bimetal


254


to undesirably break apart during such high current conditions.





FIGS. 22A and 22B

depict an embodiment of load terminal


28


that may be used in circuit breaker


10


. That embodiment, formed of stamped stainless steel having a thickness of approximately 0.047 inches, is most useful in applications where electrical current will normally be below approximately


30


amps. For higher current applications, another embodiment of a load terminal may advantageously be used, as shown in

FIGS. 28A

,


28


B, and


23


C. In order to better accommodate the higher currents, terminal


28


A of this embodiment is formed of stamped copper or brass of an increased thickness of approximately 0.093 inches. Terminal


28


A includes a substantially planar portion


330


(again tapered) from which protrudes, in approximately perpendicular fashion, a bottom connector portion


332


with a hole or opening


334


extending therethrough. Connector


332


also includes indents


331


on the top thereof, cutouts


333


that cause front face


335


to have a smaller width than the rest of connector


332


, and a notch or cutout


337


extending from the bottom of front face


335


towards opening


334


, as shown in FIG.


28


C. Located at the other end of terminal


28


A is a top substantially planar region


336


which is offset from portion


330


via a curved region


338


. Formed through portion


330


are holes or openings


340


(for securement to magnetic yoke


252


) and holes or openings


342


(for attachment of the two springs


253


). A tab or protrusion


344


(having the same purpose as protrusion


306


of terminal


28


) protrudes from one side of portion


330


, with a corresponding cavity


346


on the other side. Ribbed portions


348


are also formed in portion


330


for the reasons described above with respect to ribbed portions


308


of terminal


28


. Ribbed portions


348


are not as pronounced as ribbed portions


308


due to the general increased thickness of terminal


28


A as compared to terminal


28


, although they provide a similarly snug fit within channels


520


of base


12


. Also shown are support ribs


350


for enhancing the strength of curved region


338


. The operation of terminal


28


A within circuit breaker


10


and, in particular, automatic trip assembly


250


, is essentially the same as described above in connection with terminal


28


.




Referring now to

FIG. 29

, shown is an example self-retaining collar


295


that may be used with either load terminal


28


(or


28


A) or line terminal


29


to connect external conductors thereto. Collar


295


includes a base portion


480


having a substantially open-ended square shape. Base


480


includes inwardly-facing detents or protrusions


482


formed in the two vertical sides thereof, and an upwardly-facing circular protrusion or raised surface


484


formed on the bottom. A neck


486


is formed on the top of base


480


, defining an opening through which a top portion


488


is inserted. In the exemplary embodiment, top portion


488


is a screw having a clamp portion


490


rotatably connected to the bottom thereof.




In use, collar


295


is connected onto the end of one of the terminals of circuit breaker


10


. Describing this connection with respect to load terminal


28


shown in

FIGS. 22A and 22B

, connector portion


292


of terminal


28


is inserted into base


480


such that raised surfaces


297


abut detents


482


, and until opening


294


is engaged by circular protrusion


484


. Cutouts


299


of terminal


28


facilitate this insertion because they enable front face


301


, which has a width that is smaller than the inner width of base


480


, to easily slide in and “channel” the remainder of connector


292


therein. Protrusion


484


of collar


295


provides an interference fit with opening


294


that resists lateral movement of the collar relative to terminal


28


. Detents


482


of collar


295


prevent vertical movement of the collar relative to terminal


28


, and the enhanced frictional engagement provided by raised surfaces


297


of connector


292


also resists lateral movement of the collar relative to terminal


28


.




Positioned as such (as shown in FIG.


4


), collar


295


is in a self-retained disposition.




Describing the connection of collar


295


with respect to load terminal


28


A shown in

FIGS. 28A and 28B

, connector portion


332


of terminal


28


A is likewise inserted into base


480


such that its top surface abuts detents


482


, and until opening


334


is engaged by circular protrusion


484


. Like cutouts


299


of terminal


28


, cutouts


333


of terminal


28


A facilitate this insertion and provide a similar channeling effect for the remainder of connector


332


. Notch or cutout


337


of connector


332


also facilitates the insertion because it is appropriately sized and configured to channel circular protrusion


484


of collar


295


under connector


332


which is beneficial since connector


332


is of increased thickness as compared to connector


292


of terminal


28


. Protrusion


484


of collar


295


provides an interference fit with opening


334


that resists lateral movement of the collar relative to terminal


28


A. Detents


482


of collar


295


snap into indents


331


of connector


332


, providing an interference fit that also resists lateral movement of collar


295


relative to terminal


28


A, with detents


482


also preventing vertical movement of collar


295


relative to terminal


28


A. A self-retained disposition of collar


295


is thus realized.




After collar


295


is connected onto the end of one of the terminals of circuit breaker


10


, the end of an external conductor can then be inserted between clamp


490


and the top surface of the terminal's connector portion. Clamp


490


can then be lowered by means of rotation of screw


488


until the clamp frictionally secures the external conductor to the terminal. External access to screw


488


is provided by way of one of holes


20


in cover


14


(FIG


1


) which enables a tool such as a screwdriver to be inserted and to appropriately manipulate screw


488


.




Referring now to

FIGS. 30A and 30B

, shown are cradle


72


and cradle pivot pin


82


of the present invention. As shown in

FIGS. 12 and 13

, pin


82


is laterally and rotatably disposed between sideplates


84


of circuit breaker


10


, and provides a point of rotation for cradle


72


. As shown in

FIG. 30A

, cradle


72


has an opening


393


through which upper toggle link pivot pin


78


extends. Cradle


72


also includes an aperture


390


consisting of a smaller cutout or hole


392


interconnected with (blending into) a larger cutout or hole


394


. Larger cutout


394


is sized so as to be larger than the thickest diameter portion of pin


82


. Before pin


82


is positioned between holes


396


and


398


of sideplates


84


(see FIG.


13


), pin


82


is easily inserted midway through larger cutout


394


of aperture


390


. Because substantial pressure is not required in order to insert pin


82


through cutout


394


, pin


82


may advantageously be heat-treated for strength so that it is more capable of withstanding the higher internal temperatures sometimes encountered in circuit breakers. As shown in

FIG. 30B

, pin


82


includes a stepped-inward portion


397


midway along its length. Pin


82


(presently inserted in larger cutout


394


) is then shifted such that portion


397


becomes seated into smaller cutout


392


, cutout


392


being sized to provide engagement therewith while at the same time, in the exemplary embodiment, enabling pin


82


to rotate therein. Because portions


397


A of pin


82


around stepped-inward portion


397


are too thick to fit within smaller cutout


392


, they provide shoulders which ensure that cradle


72


remains centered on pivot pin


82


. When pin


82


is then rotatably positioned between holes


396


and


398


of sideplates


84


, cradle


72


is able to rotate during the tripping and resetting operations of circuit breaker


10


described above. This rotation can occur in one of two manners: cradle


72


may rotate on (independently of) pin


82


, or cradle


72


may rotate with pin


82


(within holes


396


and


398


of sideplates


84


). These two methods of rotation are advantageous in that they provide increased flexibility to the operation of operating mechanism


38


. In particular, proper rotation of cradle


72


can still occur even if pin


82


somehow locks up and cannot rotate within holes


396


and


398


of sideplates


84


.




During the assembly process, stop bar


88


serves to help maintain the engagement of stepped-inward portion


397


of pivot pin


82


with smaller cutout


392


of cradle


72


. As shown in

FIGS. 6 and 8

, stop bar


88


is positioned close to, and substantially to the left and below, an indent or cutout portion


395


of cradle


72


when the cradle is in an assembly-conducive position as depicted. Positioned as such, stop bar


88


has a tendency to abut indent


395


if cradle


72


moves downwardly and/or to the left, thus preventing substantial movement in those directions which could result in a loose seating of pivot pin


82


in larger cutout


394


. In the totally assembled circuit breaker


10


, the pair of side-by-side compression springs (not shown) acting upon cradle


72


provide a spring force which also serves to keep smaller cutout


392


engaged with stepped-inward portion


397


of pivot pin


82


. Although stop bar


88


and the pair of side-by-side compression springs maintain the aforementioned engagement, they nonetheless enable a little “give” to exist in that engagement whereby cradle


72


may advantageously move a small distance about pivot pin


82


which provides increased flexibility to the operation of operating mechanism


38


.




Referring again to

FIGS. 12 and 13

, stop bar


88


is shown laterally disposed between sideplates


84


. Stop bar


88


includes ends


450


which are, in the exemplary embodiment, of a smaller diameter than the main portion of bar


88


and separated therefrom by shoulders


452


. During assembly, ends


450


are inserted into holes


454


of sideplates


84


until shoulders


452


(which have a larger diameter than openings


454


) contact inner surfaces


84


B of sideplates


84


. After this insertion, portions


450


A of ends


450


protrude out of holes


454


along the outer surfaces


84


A of sideplates


84


. A machine, such as an orbital riveter, is then used to inwardly spin press portions


450


A until outer shoulders


456


are formed (only one is shown) which, although of sufficient thickness to be structurally firm, are thin enough so that they are substantially flush with respect to outer surfaces


84


A of sideplates


84


. Because outer shoulders


456


have a larger diameter than openings


454


, they cooperate with inner shoulders


452


to help maintain the spacing between sideplates


84


. In particular, outer shoulders


456


will resist further outward separation of sideplates


84


potentially caused by, for example, forces generated during high current interruption. Inner shoulders


452


resist any inward movement of sideplates


84


(towards each other) that could potentially occur. This maintenance of the spacing between sideplates


84


serves to help ensure proper positioning and functioning of operating mechanism


38


components.




Also shown in

FIGS. 12 and 13

is a support bar


460


laterally disposed between sideplates


84


. Similar to stop bar


88


, support bar


460


includes ends


462


which are, in the exemplary embodiment, of a smaller diameter than the main portion of bar


460


and separated therefrom by shoulders


464


. During assembly, ends


462


are inserted into holes


466


of sideplates


84


until shoulders


464


(which have a larger diameter than openings


466


) contact inner surfaces


84


B of sideplates


84


. After this insertion, portions


462


A of ends


462


protrude out of holes


466


along the outer surfaces


84


A of sideplates


84


. A machine, such as an orbital riveter, is then used to inwardly spin press portions


462


A until outer shoulders


468


are formed (only one is shown). Although outer shoulders


468


are of sufficient thickness to be structurally firm, they are thin enough to be substantially flush with respect to outer surfaces


84


A of sideplates


84


. Because outer shoulders


468


have a larger diameter than openings


466


, they cooperate with inner shoulders


464


, and with stop bar


88


, to help maintain the spacing between sideplates


84


, in the manner described above in connection with stop bar


88


.




In a preferred embodiment, stop bar


88


and support bar


460


are formed of carbon steel metal. In addition, holes


466


for support bar


460


are preferably formed in areas of sideplates


84


that are substantially on the opposite side of where holes


454


are formed for stop bar


88


. Such positioning of stop bar


88


and support bar


460


provides for proper spacing maintenance of sideplates


84


along their entire length. In the exemplary embodiment, support bar


88


is positioned between trip bar assembly


190


and crossbar assembly


60


, the exact positioning and size thereof selected so that it does not interfere with rotation of those components. In other embodiments, additional support bars may, of course, be used in order to further ensure proper spacing between sideplates


84


.




Referring now to FIG.


31


and again to

FIGS. 12 and 13

, shown are handle assembly


70


and associated parallel sideplates


84


of the sideplate or support member assembly of circuit breaker


10


. Handle assembly


70


is formed of metal in the exemplary embodiment, and includes parallel and symmetrical handle assembly plates


100


that are connected together by a handle platform


101


that interconnects with handle


24


of circuit breaker


10


as described below. Each handle assembly plate


100


includes an opening


102


(only one of which is shown in

FIG. 31

) through which handle assembly roller


86


extends (FIG.


5


), and each also includes a circular pivot region


104


that rotatably mates with a corresponding pivot surface cutout


106


(

FIG. 12

) in each sideplate


84


. Also shown are handle assembly actuation tabs or protrusions


108


that protrude from the bottom of each handle assembly plate


100


, each including an inwardly curved portion or contact member


109


. Each sideplate


84


includes an actuation tab cutout region


110


, including a bottom portion


111


, that corresponds with each actuation tab


108


and provides for clearance thereof throughout a range of motion of handle assembly


70


during normal operation of circuit breaker


10


, as described below. As shown in

FIGS. 12 and 13

, each sideplate


84


also includes an opening


105


into which is inserted the stem or shaft


107


A of a stop or tab


107


having a head portion


107


B. Stops


107


are configured so that they may be manufactured by a screw-machining process. The end of each stem


107


A is spin pressed, for example by an orbital riveter, in order to secure stops


107


to sideplates


84


, with head portions


107


B positioned along the outer surfaces


84


A of the sideplates and at least partially externally overlapping pivot surface cutouts


106


. Secured as such, stops


107


prevent pivot regions


104


of handle assembly


70


from becoming outwardly disengaged from pivot surface cutouts


106


in sideplates


84


due to, for example, outward forces generated during high current interruption.




Referring now also to

FIGS. 32 and 33

, and again to

FIGS. 6 and 7

, shown in

FIG. 32

is cam housing


62


of crossbar assembly


60


without a cam follower inserted therein. Disposed on and protruding generally from the top of cam housing


62


are stop members


112


.

FIG. 7

depicts the disposition of cam housing


62


, sideplates


84


, and handle assembly


70


when circuit breaker


10


is in the ON disposition. Note that, in order to provide for a normal range of movement of handle assembly


70


towards an OFF position, actuation tabs or arms


108


are separated from the bottom portion


111


of cutout region


110


. The tops of stop members


112


are internally positioned between sideplates


84


adjacent to actuation tab cutout regions


1




10


and not far below curved portions


109


of actuation tabs


108


. As such, stop members


112


are positioned to abut against curved portions


109


when handle


24


is attempted to be moved clockwise towards an OFF position at a time when contacts


52


and


56


and crossbar assembly


60


nonetheless remain in the ON disposition (such as when contacts


52


and


56


are in a welded-closed disposition). This abutment (shown in FIG.


33


), which occurs after a slight rotational movement of handle assembly


70


, prevents further movement of assembly


70


in the clockwise direction -(through the range of motion normally enabled by cutout regions


110


), thereby preventing handle


24


from indicating that circuit breaker


10


in in the OFF disposition when in fact it is not. As such, a clear indication is provided that contacts


52


and


56


have not opened even though an opening operation has been attempted. However, in normal operation when contacts


52


and


56


can be opened, stop members


112


rotate clockwise with crossbar assembly


60


(and contact


52


) when handle assembly


70


is moved clockwise towards the OFF position. As such, stop members


112


rotate away from actuation tab cutout regions


110


, as shown in FIG.


6


. This allows for full movement of actuation tabs


108


within regions


110


which, in turn, allows handle


24


to move to the OFF position.




Referring now also to

FIGS. 34A

,


34


B,


34


C, and


34


D, shown is handle


24


of circuit breaker


10


which, in the preferred embodiment, is molded of an insulator material such as plastic. Handle


24


includes a top portion


403


, and a base


404


having a top curvilinear surface


405


and a bottom cavity region


406


. Cavity region


406


includes protrusions


408


that define two channels


407


into which sides


101


A and


101


B of handle platform


101


(

FIG. 31

) of handle assembly


70


are inserted (as shown in, for example,

FIGS. 4

,


5


, and


6


) to form an engagement connecting handle


24


to assembly


70


. This connection enables manual movement of handle


24


to cause operating mechanism


38


to change disposition, as described above. Disposed approximately midway within one channel


407


(in the exemplary embodiment), between protrusions


408


, is an integrally formed protrusion or nubb


409


(

FIG. 34D

) which, like the rest of handle


24


, is preferably formed of an insulating material such as plastic which is at least partially compressible. Side


101


B of platform


101


(

FIG. 31

) includes, approximately midway therein, an indent or cutout


411


of approximately the same size and shape as protrusion


409


. When platform


101


of handle assembly


70


is inserted into channels


407


, protrusion


409


will deform (compress) slightly as it travels over the flat portions of sides


101


B. As shown in the exemplary embodiment, protrusion


409


is preferably rounded in shape so as to facilitate this travel. When platform


101


is fully inserted into channels


407


, protrusion


409


will return to its normal shape and become seated within indent


411


. As such, protrusion


409


and indent


411


serve to center the connection between handle


24


and handle platform


101


. In addition, the frictional engagement of protrusion


409


with indent


411


serves to resist movement of platform


101


within channels


407


, thereby providing a more secure connection between platform


101


and handle


24


. In an alternative embodiment, a protrusion


409


may be disposed in each channel


407


, with corresponding indents


411


formed in both of sides


101


A and


101


B of platform


101


.




As shown in

FIG. 34B

, base


404


of handle


24


includes a first side


410


with a curvilinear top surface section


405


A and terminating with an end portion


414


which (in the exemplary embodiment) is substantially triangular in shape. A second side


416


is somewhat symmetrical to that of first side


410


, except that it terminates with an end portion


418


that is truncated in comparison to end portion


414


, providing a truncated curvilinear top surface section


405


B. In the exemplary embodiment, end portion


418


is substantially concave in shape. Truncated end portion


418


clearly occupies less space than end portion


414


, and is configured so as to not interfere (make contact) with other internal workings of circuit breaker


10


throughout the range of motion of handle


24


. In particular, end portion


418


is configured so as to not interfere with automatic trip assembly


250


of trip mechanism


40


when circuit breaker


10


is in the OFF disposition or during a resetting operation, as shown in

FIGS. 6 and 9

, respectively.




Referring now also to

FIGS. 35-38

, shown in

FIG. 35

is a curved handle slider


424


having an opening


426


, a convex top surface


428


, and a concave bottom surface


430


. Within circuit breaker


10


, slider


424


is positioned in a substantially overlapping relationship with handle


24


whereby bottom surface


430


is placed on top of and substantially overlaps top surface


405


of handle


24


, and top portion


403


of handle


24


protrudes through opening


426


. As shown in

FIGS. 36 and 37

, handle


24


and overlapping slider


424


are positioned in relation to cover


14


whereby top portion


403


of handle


24


also protrudes through opening


22


of the cover. In a conventional manner, slider


424


moves along a bottom surface


434


of cover


14


as handle


24


is rotated through its range of motion. The overlapping relationship of slider


424


with handle


24


, along with the fact that (in the exemplary embodiment) opening


426


of slider


424


is smaller than opening


22


of cover


14


, provides a barrier which helps to prevent foreign items entered into opening


22


from reaching the internal workings of circuit breaker


10


. For this purpose, slider


424


preferably is thick enough such that it will not easily flex inward. In a preferred embodiment, slider


424


is approximately 0.055 inches thick of celcon thermoplastic material. Although thick enough to resist significant inward flex, slider


424


is relatively thin compared to base


404


of handle


24


, and is thin enough to arc or ride over automatic trip assembly


250


of trip mechanism


40


without interference (as can be seen in FIG.


3


).




As handle


24


is rotated through its range of motion, top surface


428


of slider


424


makes contact with bottom surface


434


of cover


14


along arches


436


thereof. This contact reduces the chances of separation that could compromise the barrier protection described above. As best shown in

FIG. 38

, base


404


includes grooves


438


that extend along the side edges of top surface


405


from end portion


414


to end portion


418


. As top surface


428


of slider


424


makes contact with arches


436


of cover


14


throughout the range of motion of handle


24


, this contact causes a slight deflection of the side edges of slider


424


into grooves


438


. This deflection reduces the friction between slider


424


and bottom surface


434


of cover


14


, enabling handle


24


to smoothly rotate through its range of motion. As such, grooves


438


enable a thicker slider


424


to be implemented than otherwise would be possible within the tight space constraints of circuit breaker


10


, making the slider more resistant to inward flex and thus providing enhanced barrier protection. In the exemplary embodiment, grooves


438


are approximately 0.030 inches deep.




In addition to having a truncated end portion


418


, base


404


of handle


24


includes a cut-away section


440


near one corner of end portion


418


, as best shown in

FIGS. 34A and 34D

. As shown in

FIG. 15

, cut-away section


440


provides clearance for button


25


of push-to-trip actuator


230


, particularly when circuit breaker


10


is in the OFF disposition or during a resetting operation. As also shown in

FIG. 15

, working in conjunction with cut-away section


440


is cutout


238


of button


25


which is positioned to provide clearance for slider


424


(not shown) throughout the range of motion of handle


24


. Cutout


238


is sufficiently large so that top portion


25


A of button


25


can be depressed notwithstanding the presence of slider


424


within cutout


238


. As such, cutout


238


of button


25


and cut-away section


440


of handle


24


cooperate in order to prevent interference between push-to-trip actuator


230


and the combination of handle


24


and slider


424


.




Referring now to

FIGS. 39 and 40

, and again to

FIG. 2

, particular attention is directed to the profile between base


12


and cover


14


of circuit breaker


10


. Base


12


is shown having a top region generally designated


120


, and cover


14


is shown having a bottom region generally designated


122


. Top region


120


of base


12


includes raised portions


124


that mate with corresponding cut-away or recessed portions


126


in bottom region


122


of cover


14


. As shown in the side cross-sectional view of

FIG. 40

taken along the line


40





40


of

FIG. 1

, when cover


14


is connected to base


12


, appropriate attaching devices


128


(comprising mounting screws in the exemplary embodiment) are inserted into holes or openings


16


(

FIG. 2

) in cover


14


above recessed portions


126


and enter corresponding holes or openings


18


in raised portions


124


of base


12


. Attaching devices


128


are selected so that, upon full insertion, the bottoms thereof do not substantially, if at all, penetrate base


12


below its raised portions


124


. As such, this mounting arrangement conserves space within the main body of base


12


whereby attaching devices


128


do not interfere with the internal workings therein. The dimensions of raised portions


124


and recessed portions


126


are selected so that attaching devices


128


can nonetheless penetrate a sufficient depth into base


12


so as to provide a sufficiently strong connection between base


12


and cover


14


. In one exemplary embodiment, attaching devices


128


are approximately 1 inch in length and penetrate approximately ½ inch into raised portions


124


of base


12


.




As shown in FIG.


40


and described above, attaching devices


128


provide a mounting arrangement between base


12


and cover


14


. Referring now also to

FIG. 41

, attaching device


128


of the exemplary embodiment is shown including a main member


132


comprising a mounting screw with a head


134


and a body separated into a non-gripping (non-threaded) portion


136


and a gripping (threaded) portion


138


. Attaching device


128


also includes a compressible member


140


that (when fully assembled) is adjacent to head


134


and engaged by non-threaded portion


136


of mounting screw


132


. Compressible member


140


may be an elastomeric washer (as in the exemplary embodiment), or it may be another compressible device such as a spring. In the cross-sectional view of

FIG. 40

, attaching device


128


is shown assembled and inserted into opening


16


(

FIG. 2

) in cover


14


and corresponding opening


18


in base


12


.

FIG. 40

shows gripping portion


138


extending into and attaching with base


12


, non-gripping portion


136


extending through cover


14


, and head


134


providing a stop for limiting the possible separation between base


12


and cover


14


. Compressible member


140


is shown in a position between head


134


and a top surface of cover


14


. In this mounting arrangement, the compressibility of member


140


permits base


12


and cover


14


to temporarily and substantially instantaneously separate a small distance when pressure develops within circuit breaker


10


such as due to the generation of gases during high current interruption (opening of contacts


52


and


56


). This separation along the interface between base


12


and cover


14


allows the generated gases to be vented, providing a pressure release that protects the structural integrity of circuit breaker


10


.




Referring now to

FIGS. 42

,


43


,


44


A,


44


B,


45


A,


45


B,


45


C, and


46


, shown are support members


150


A and


150


B of circuit breaker


10


in connection with base


12


and cover


14


. Base


12


includes sidewalls


152


within which are formed slots


154


A and


155


A. As shown in

FIG. 43

which depicts a top view of base


12


without components therein, sidewalls


152


also include grooves or channels


156


adjacent to slots


154


A, and grooves or channels


157


adjacent to slots


155


A, both formed on the outer surfaces


152


A of sidewalls


152


. Base


12


also includes small recesses


21


A formed in the top of sidewalls


152


. Cover


14


includes sidewalls


153


(only one of which is viewable in

FIG. 42

) within which are formed slots


154


B and


155


B which align with slots


154


A and


155


A, respectively, of base


12


when cover


14


is positioned on top of base


12


. Sidewalls


153


also include grooves or channels that are similar to channels


156


and


157


of base


12


.




Support member


150


A includes a pair of shoulders or support wings


158


and a connection wall


160


therebetween, forming essentially an I-beam as shown in

FIGS. 44A and 44B

. Support member


150


A of the exemplary embodiment also includes an opening


159


and a cutout region


161


that substantially extends upwardly into wall


160


. Support member


150


B includes a pair of shoulders or support wings


162


and a connection wall


163


therebetween, also forming essentially an I-beam as shown in

FIGS. 45A

,


45


B, and


45


C. In the exemplary embodiment, wall


163


includes an elongated integral housing


164


having an upwardly extending cutout region


165


.




In use, as shown in

FIG. 46

, support member


150


A is inserted into slots


154


A of base


12


whereby shoulders


158


engage grooves


156


. In this position, connection wall


160


is disposed internally within the body of base


12


and generally perpendicular to sidewalls


152


. In relation to the other internal components of circuit breaker


10


, support member


150


A is disposed between arc extinguisher assembly


34


and slot motor assembly


32


in the exemplary embodiment. In that position, the clearance provided by cutout region


161


facilitates the transfer of arcs (created by contact separation) to arc chute


46


of arc extinguisher assembly


34


in order to be dissipated, while wall


160


serves as a barrier for protecting the internal workings of circuit breaker


10


(those components to the left of support member


150


A as viewed in

FIG. 46

) from arcing and/or hot gases. Cutout region


161


also ensures that movable contact arm


50


has sufficient room to move throughout its required range of motion. Opening


159


provides clearance for upper arc runner


48


A (

FIG. 3

) of arc chute


46


which is inserted therethrough.




As also shown in

FIG. 46

, support member


150


B is inserted into slots


155


A of base


12


whereby shoulders


162


engage grooves


157


. As such, connection wall


163


is disposed internally within the body of base


12


and generally perpendicular to sidewalls


152


. In relation to the other internal components of circuit breaker


10


, support member


150


B is disposed between slot motor assembly


32


and sideplates


84


in the exemplary embodiment. In that position, cutout region


165


provides clearance for movable contact arm


50


to move throughout its required range of motion. Elongated housing


164


serves to fill vacant space between slot motor assembly


32


and sideplates


84


, and works with the rest of wall


163


to act as a barrier for protecting the internal workings of circuit breaker


10


(those components to the right of support member


150


B as viewed in

FIG. 46

) from arcing and/or hot gases potentially created by contact separation.




Cover


14


is then placed on top of base


12


, whereby the tops of support members


150


A and


150


B are inserted into slots


154


B and


155


B, respectively, and shoulders


158


and


162


engage their respective grooves, as shown in FIG.


1


. Disposed as such, the I-beam nature of each of support members


150


A and


150


B prevents or limits further separation of sidewalls


152


and


153


due to circumstances such as the buildup of pressure within circuit breaker


10


resulting from the generation of gases during high current interruption (opening of contacts


52


and


56


). In addition, shoulders


158


and


162


are appropriately dimensioned and manufactured of suitable material so as to enable support members


150


A and


150


B to also allow venting of circuit breaker


10


whereby pressure can be released. Upon a particular threshold pressure within circuit breaker


10


, the outer edges of shoulders


158


and


162


“wing” slightly outward (away from the grooves) to provide this outward venting through slots


154


A,


154


B,


155


A, and


155


B, while at the same time maintaining sidewalls


152


and


153


at or near a constant separation distance. The width of connection walls


160


and


163


near shoulders


158


and


162


, respectively, are selected so as to permit such venting through the slots notwithstanding the presence of those portions in the slots. Additional venting is provided by openings


21


(

FIG. 1

) which are formed at the interface between recesses


21


A of base


12


and the bottom of sidewalls


153


of cover


14


. Openings


21


are small enough and appropriately configured so that insertion of foreign items therein is substantially prevented.




Although two support members


150


A and


150


B are implemented in the exemplary embodiment, other numbers of such support mechanisms may, of course, be employed. Furthermore, the exact placement of one or more such support members is preferably experimentally established via the analysis of stress conditions in the base and cover of a particular circuit breaker. In one embodiment, support members


150


A and


150


B are formed of molded material comprising quantum


8800


(60% glass reinforced).




Now referring to

FIGS. 47A and 47B

, shown is an insulation barrier or deflector


500


of the present invention. Deflector or shield


500


includes a vertical wall


502


having sides with channels or grooves


504


. Integrally connected to wall


502


is a shoulder


506


on which is formed a rounded cap


508


. An opening


509


is formed in the top of cap


508


, and an opening


510


is formed in the underside of shoulder


506


, forming a cylindrical cavity therebetween. In one embodiment, deflector


500


is integrally molded of a thermoset plastic material.




Now referring also to

FIGS. 48 and 49

, shown in

FIG. 48

is a side elevational view of the internal components of circuit breaker


10


without arc extinguisher assembly


34


. Line terminal


29


is shown connected to a self-retaining collar


295


. In

FIG. 49

, deflector


500


is shown positioned above collar


295


, with cap


508


on top of and covering screw


488


such that screw


488


may at least be partially inserted within opening


510


. Vertical wall


502


of deflector


500


is positioned along the side of collar


295


that normally faces arc extinguisher assembly


34


.




Referring also now to

FIG. 50

, shown is deflector


500


in relation to base


12


and cover


14


(the other circuit breaker components, including collar


295


, not shown for the sake of clarity). When deflector


500


is implemented within circuit breaker


10


, it is vertically slid into base


12


such that grooves


504


engage vertically-extending protrusions


514


which are formed on the inner surfaces


152


B of sidewalls


152


(see also FIG.


43


). This engagement substantially prevents any lateral movement of deflector


500


relative to base


12


, and enables vertical wall


502


to extend substantially perpendicularly between sidewalls


152


of base


12


without any gaps near its edges. Protrusions or rails


514


are, of course, appropriately positioned in base


12


so that a fully inserted deflector


500


is properly aligned with respect to the collar


295


that is connected to line terminal


29


. When cover


14


is secured to base


12


, portions of cover


14


are positioned close to and above the top of cap


508


whereby vertical movement of deflector


500


relative to base


12


is also substantially prevented. In addition, one of holes


20


of cover


14


aligns with opening


509


of deflector


500


, thereby enabling a tool such as a screwdriver to be externally inserted into the cavity of cap


508


and to appropriately manipulate screw


488


(

FIG. 29

) of collar


295


in order to tighten or loosen the connection of line terminal


29


to an external conductor.




Positioned as described above within circuit breaker


10


, deflector


500


provides an insulation barrier for effectively protecting collar


295


from arcing and/or hot gases that may be generated within circuit breaker


10


, particularly during interruption of high currents.




Referring now to

FIGS. 51-54

, shown is an example of a conventional multi-wire lug assembly


360


that may be used as an accessory for circuit breaker


10


to enable more than one conductor line to be routed therethrough. Assembly


360


includes a body


362


with a plurality of lugs


364


arranged in step-like fashion thereon. Assembly


360


also includes a front wall


365


from which protrudes an appropriately configured connector portion


366


that is insertable into load conductor opening


26


in base


12


(see

FIG. 1

) and securable to load terminal


28


of circuit breaker


10


via a securement device such as self-retaining collar


295


. Also shown is a lug insulator


370


of the present invention. Insulator


370


includes a main body


372


formed of two substantially parallel plates


374


with a wall


376


(

FIG. 52

) therebetween. Near its front, insulator


370


also includes an integral locking strap or locking structure


378


with two vertical side bars


379


and a horizontal bar


381


therebetween forming an opening


380


that is appropriately sized and configured for insertion of connector


366


of lug assembly


360


therein. Each plate


374


includes a tapered portion


382


, a front portion


383


, and, in the exemplary embodiment, an internally disposed protrusion


384


(only one is shown). In a preferred embodiment, insulator


370


is comprised of thermoplastic material.




As shown in

FIG. 53

, before connection to a circuit breaker, lug assembly


360


may advantageously be assembled to lug insulator


370


, with body


362


placed between plates


374


and connector


366


inserted through opening


380


of locking strap


378


until front wall


365


contacts bars


379


and bar


381


of locking strap


378


. Positioned as such, a top surface


363


of lug assembly


360


abuts against the bottoms of protrusions


384


of plates


374


. This abutment, along with wall


376


(

FIG. 52

) of insulator


370


and horizontal bar


381


of locking strap


378


, serves to help secure lug assembly


360


to lug insulator


370


and prevent vertical separation therebetween. After the aforementioned assembly, connector


366


of lug assembly


360


may then be inserted, in normal fashion, into load conductor opening


26


in base


12


of circuit breaker


10


(as shown in

FIG. 54

) and secured to load terminal


28


via a securement device such as collar


295


(not visible). Note that front portions


383


of plates


374


abut against external surfaces of base


12


, providing enhanced stability to the connection. Once connector


366


is secured to load terminal


28


, insulator


370


is locked in place and cannot be separately removed (pulled away) due to the contact between locking strap


378


thereof and front wall


365


of lug assembly


360


.




Lug insulator


370


provides electrical insulation for multi-wire lug assembly


360


. While providing this protective insulation, lug insulator


370


nonetheless provides easy access to lugs


364


of lug assembly


360


. In particular, tapered portions


382


of plates


374


follow the step-like configuration of lugs


364


so that convenient access is provided for all lugs.




Although the preferred embodiment of the present invention has been described with a certain degree of particularity, various changes to form and detail may be made without departing from the spirit and scope of the invention as hereinafter claimed.



Claims
  • 1. A circuit interrupter comprising:a housing; separable main contacts within said housing; an operating mechanism within said housing and interconnected with said separable main contacts, said operating mechanism including a cradle for moving from a first position to a second position in the event of a tripping operation and causing said contacts to open; and a trip mechanism within said housing and including a rotatable trip bar assembly that, when rotated, generates said tripping operation, said trip mechanism including a rotatable latch for engaging said trip bar assembly and said cradle and keeping said cradle in said first position when said tripping operation has not occurred, said trip mechanism further including a bias member disposed on said trip bar assembly and positioned to rotationally bias said trip bar assembly and said latch.
  • 2. The circuit interrupter as defined in claim 1 wherein said bias member is a spring.
  • 3. The circuit interrupter as defined in claim 2 wherein said spring includes a protruding end that contacts and biases said latch.
  • 4. The circuit interrupter as defined in claim 1 wherein said bias member biases said latch in a first rotational direction, said latch rotating in a second rotational direction when said tripping operation is initiated, and wherein said first rotational direction is opposite of said second rotational direction.
  • 5. The circuit interrupter as defined in claim 1 wherein said bias member biases said latch in a first rotational direction, and further including a stop disposed within said housing for limiting the rotation of said latch in a direction opposite of said first rotational direction.
  • 6. The circuit interrupter as defined in claim 1 wherein said trip bar assembly includes a trip shaft extending along the axis of rotation of said trip bar assembly, and wherein said bias member is disposed on said trip shaft.
  • 7. The circuit interrupter as defined in claim 6 wherein said bias member is a torsion spring having a protruding end, and wherein said torsion spring is wound around said trip shaft with said protruding end contacting said latch.
  • 8. The circuit interrupter as defined in claim 7 wherein said trip shaft has two ends, and wherein said torsion spring is wound around one of said two ends.
  • 9. The circuit interrupter as defined in claim 1 wherein said bias member biases said trip bar assembly and said latch in the same rotational direction.
  • 10. A circuit interrupter comprising:a housing; separable main contacts within said housing; an operating mechanism within said housing and interconnected with said separable main contacts, said operating mechanism including a cradle for moving from a first position to a second position in the event of a tripping operation and causing said contacts to open; and a trip mechanism within said housing and including a rotatable trip means that, when rotated, generates said tripping operation, said trip mechanism including a rotatable latching means for engaging said trip means and said cradle and keeping said cradle in said first position when said tripping operation has not occurred, said trip mechanism further including a biasing means disposed on said trip means and positioned to rotationally bias said trip means and said latching means.
CROSS REFERENCE TO RELATED APPLICATIONS

The subject matter of this invention is related to concurrently filed, co-pending applications: U.S. patent application Ser. No. 09/384,780, filed Aug. 27, 1999, entitled “Insulator For A Lug Assembly Accessory Of A Circuit Interrupter”; U.S. patent application Ser. No. 09/384,450, filed Aug. 27, 1999, entitled “Circuit Interrupter With Improved Welded Contact lnterlock”; U.S. patent application Ser. No. 09/385,643, filed Aug. 27, 1999, entitled “Circuit Interrupter With Space Conserving Handle Mechanism”; U.S. patent application Ser. No. 09/384,449, filed Aug. 27, 1999, entitled “Circuit Interrupter With Housing Support”; U.S. patent application Ser. No. 09/384,943, filed Aug. 27, 1999, entitled “Circuit Interrupter With Space Conserving Base/Cover Attachment”; U.S. patent application Ser. No. 09/384,447, filed Aug. 27, 1999, entitled “Circuit Interrupter With Base/Cover Attachment Enabling Venting”; U.S. patent application Ser. No. 09/384,445, filed Aug. 27, 1999, entitled “Circuit Interrupter With Improved Push-To-Trip Actuator”; U.S. patent application Ser. No. 09/384,914, filed Aug. 27, 1999, entitled “Circuit Interrupter With An Improved Electrical Terminal For Attachment To A Connecting Device”; U.S. patent application Ser. No. 09/384,146, filed Aug. 27, 1999, entitled “Circuit Interrupter With An Improved Magnetically-Induced Automatic Trip Assembly”; U.S. patent application Ser. No. 09/384,654, filed Aug. 27, 1999, entitled “Circuit Interrupter With An Improved Magnetically-Induced Trip Mechanism”; U.S. patent application Ser. No. 09/384,140, filed Aug. 27, 1999, entitled “Circuit Interrupter With An Improved Magnetically-induced Automatic Trip Assembly”; U.S. patent application Ser. No. 09/385,585, filed Aug. 27, 1999, entitled “Circuit Interrupter With An Operating Mechanism Having Improved Support”; U.S. patent application Ser. No. 09/384,330, filed Aug. 27, 1999, entitled “Circuit Interrupter Including An Insulation Barrier For A Connecting Device”; U.S. patent application Ser. No. 09/385,658, filed Aug. 27, 1999, entitled “Circuit Interrupter With Improved Handle Interconnection”; U.S. patent application Ser. No. 09/384,148, filed Aug. 27, 1999, entitled “Circuit Interrupter With Cradle Having An Improved Pivot Pin Connection”; U.S. patent application Ser. No. 09/384,915, filed Aug. 27, 1999, entitled “Circuit Interrupter With A Trip Mechanism Having An Improved Latch Connection”; U.S. patent application Ser. No. 09/384,958, filed Aug. 27, 1999, entitled “Circuit Interrupter With A Trip Mechanism Having A Biased Latch”; U.S. patent application Ser. No. 09/384,139, filed Aug. 27, 1999, entitled “Circuit Interrupter With A Trip Mechanism Having Improved Spring Biasing”; U.S. patent application Ser. No. 09/385,587, filed Aug. 27, 1999, entitled “Circuit Interrupter Providing Improved Securement Of An Electrical Terminal Within The Housing”; U.S. patent application Ser. No. 09/384,653, filed Aug. 27, 1999, entitled “Circuit Interrupter With A Magnetically-induced Automatic Trip Assembly Having improved Interconnection”; U.S. patent application Ser. No. 09/385,111, filed Aug. 27, 1999, entitled “Circuit interrupter With An Automatic Trip Assembly Having An Improved BiMetal Configuration”; U.S. patent application Ser. No. 09/384,138, filed Aug. 27, 1999, entitled “Circuit Interrupter With An Automatic Trip Assembly Configured For Reducing Blowoff Force”.

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4503408 Mrenna et al. Mar 1985
4594491 Leone et al. Jun 1986
4697163 Grunert et al. Sep 1987
4888570 Toda Dec 1989
5313033 Link et al. May 1994