Circuit breaker including two circuit breaker mechanisms and an operating handle

Abstract
A circuit breaker includes a housing, line and load terminals, first and second circuit breaker mechanisms, an operating handle having on and off positions, and first and second links from the operating handle to the respective first and second operating mechanisms. Each of the circuit breaker mechanisms includes a set of separable contacts in series with the other separable contacts between the line and load terminals, an operating mechanism for moving the corresponding separable contacts between open and closed positions, and a trip mechanism cooperating with the corresponding operating mechanism for moving the corresponding separable contacts from the closed to the open position thereof. The first and second links engage the first and second operating mechanisms to move the first and second separable contacts, respectively, between the corresponding closed and open positions thereof responsive to the on and off positions, respectively, of the operating handle.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




This invention relates to electrical switching apparatus and, more particularly, to circuit breakers having two or more pairs of separable contacts.




2. Background Information




Circuit breakers are used to protect electrical circuitry from damage due to an overcurrent condition, such as an overload condition or a relatively high level short circuit or fault condition. In small circuit breakers, commonly referred to as miniature circuit breakers, used for residential and light commercial applications, such protection is typically provided by a thermal-magnetic trip device. This trip device includes a bimetal, which heats and bends in response to a persistent overcurrent condition. The bimetal, in turn, unlatches a spring powered operating mechanism, which opens the separable contacts of the circuit breaker to interrupt current flow in the protected power system.




U.S. Pat. No. 5,541,561 discloses an integral electrical circuit controller apparatus including an electrical contactor having contacts, a circuit breaker having separable contacts connected in series with the electrical contactor, a trip mechanism responsive to current flowing through the separable contacts for tripping the contacts open in response to predetermined current conditions, and a current throttle impedance for limiting short circuit current.




U.S. Pat. Nos. 5,301,083 and 5,373,411 describe a remotely operated circuit breaker, which introduces a second pair of contacts in series with the main separable contacts. The main contacts still interrupt overcurrent, while the secondary contacts perform discretionary switching operations.




There exists the need to improve the operating voltage and/or interrupting capacity of circuit breakers without corresponding significant increases in cost of capital expenditures, development cycle times, and circuit breaker cost and size (e.g., width).




There is room for improvement in circuit breakers.




SUMMARY OF THE INVENTION




The present invention is directed to a circuit breaker including first and second circuit breaker mechanisms, an operating handle having on and off positions, and first and second links from the operating handle to the respective first and second operating mechanisms. The two circuit breaker mechanisms include two operating mechanisms, two trip mechanisms and two sets of separable contacts in series between line and load terminals. The links engage the operating mechanisms to move the first and second separable contacts between corresponding closed and open positions thereof responsive to the on and off positions, respectively, of the operating handle.




According to the invention, a circuit breaker comprises: a housing; line and load terminals; a first circuit breaker mechanism comprising: a first set of separable contacts, a first operating mechanism for moving the first set of separable contacts between an open position and a closed position, and a first trip mechanism cooperating with the first operating mechanism for moving the first set of separable contacts from the closed position to the open position thereof; a second circuit breaker mechanism comprising: a second set of separable contacts in series with the first set of separable contacts between the line and load terminals, a second operating mechanism for moving the second set of separable contacts between an open position and a closed position, and a second trip mechanism cooperating with the second operating mechanism for moving the second set of separable contacts from the closed position to the open position thereof; an operating handle having an on position and an off position; a first link from the operating handle to the first operating mechanism; and a second link from the operating handle to the second operating mechanism, wherein the first and second links engage the first and second operating mechanisms to move the first and second sets of separable contacts, respectively, between the corresponding closed and open positions thereof responsive to the on and off positions, respectively, of the operating handle.




Preferably, the second trip mechanism includes a bimetal element in order to provide a thermal trip function.




The second set of separable contacts may include a fixed contact and a movable contact, with the bimetal element being electrically interconnected with the movable contact. The bimetal element may have an input electrically interconnected with the movable contact of the second set of separable contacts and an output, which is electrically interconnected with the load terminal.




The first and second trip mechanisms may include a magnetic trip coil in order to provide an instantaneous magnetic trip function. The first and second sets of separable contacts may include a fixed contact and a movable contact, the magnetic trip coil of the first trip mechanism may be electrically interconnected between the line terminal and the fixed contact of the first set of separable contacts, and the magnetic trip coil of the second trip mechanism may be electrically interconnected between the movable contact of the first set of separable contacts and the fixed contact of the second set of separable contacts.




Preferably, a first arc chute is operatively associated with a first arc runner extending from the fixed contact of the first set of separable contacts, and a second arc chute is operatively associated with a second arc runner extending from the fixed contact of the second set of separable contacts and a third arc runner which is electrically interconnected with the load terminal.











BRIEF DESCRIPTION OF THE DRAWINGS




A full understanding of the invention can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which:





FIG. 1

is an isometric view of a circuit breaker in accordance with the present invention.





FIGS. 2A-2B

, when placed end-to-end, form a cross sectional view along lines


2





2


of one pole of the circuit breaker of

FIG. 1

with the operating handle assembly in the OFF position.





FIG. 3

is an isometric view, similar to the cross sectional view of a portion of FIG.


2


A and

FIG. 2B

, but with the operating handle assembly cut away to show the blocking disk.





FIG. 4

is a reverse cross sectional view along lines


4





4


of one pole of the circuit breaker of

FIG. 1

with the operating handle assembly in a blocking position.





FIG. 5

is a view similar to

FIG. 4

, but with the operating handle assembly in a snap close position.





FIG. 6A

is an isometric view of the carrier mechanism of FIG.


2


A.





FIG. 6B

is an isometric view, similar to

FIG. 6A

, but with the latch member removed to show the carrier spring.





FIG. 6C

is an isometric view, similar to

FIG. 6B

, but with the carrier cover removed.





FIG. 7

is an exploded isometric view of three circuit breaker poles and two trip actuators for each pair of the circuit breaker poles.





FIG. 8

is an isometric view of the push-to-trip pushbutton of one of the trip actuators of FIG.


7


.





FIG. 9

is an isometric view of one of the trip actuators engaging one of the circuit breaker poles of FIG.


7


.











DESCRIPTION OF THE PREFERRED EMBODIMENTS




The invention will be described as applied to a three-phase molded case circuit breaker


2


. It will become evident that the invention is applicable to other types of circuit breakers, such as single-phase or plural-phase miniature circuit breakers, and to a wide range of circuit breaker applications, such as, for example, residential, commercial, industrial, aerospace, and automotive.





FIG. 1

shows the exemplary three-phase molded case circuit breaker


2


including an electrically insulated housing


3


comprising a molded base


4


and a similarly molded cover


6


for each of three poles. The molded base


4


and molded cover


6


form a molded case


8


for each of the three poles. For the three poles, three load terminals


10


,


12


,


14


and three line terminals


16


,


18


,


20


are provided, where load terminal


10


is related to line terminal


16


, load terminal


12


is related to line terminal


18


, and load terminal


14


is related to line terminal


20


. A common or ganged handle assembly


22


manually opens and closes the exemplary three-phase circuit breaker


2


.




Referring to

FIGS. 2A-2B

, each pole of the circuit breaker


2


includes the molded base


4


, a load terminal, such as


10


, a line terminal, such as


16


, a first circuit breaker mechanism


24


, a second circuit breaker mechanism


26


, and an operating handle assembly


28


for the pole, which handle is shown in the OFF position. A first U-shaped link


30


is disposed from the operating handle assembly


28


to the first circuit breaker mechanism


24


, and a second link U-shaped


32


is disposed from the operating handle assembly


28


to the second circuit breaker mechanism


26


. The first circuit breaker mechanism


24


includes a first set of separable contacts


34


(shown open), a first operating mechanism


36


for moving the first separable contacts


34


between the open position and a closed position (shown in FIG.


5


), and a first trip mechanism


38


cooperating with the first operating mechanism


36


for moving the first separable contacts


34


from the closed position to the open position thereof. Similarly, the second circuit breaker mechanism


26


includes a second set of separable contacts


40


(shown open) in series with the first separable contacts


34


between the line terminal


16


and the load terminal


10


, a second operating mechanism


42


for moving the second separable contacts


40


between the open position and a closed position (shown in FIG.


5


), and a second trip mechanism


44


cooperating with the second operating mechanism


42


for moving the second separable contacts


40


from the closed position to the open position thereof.




The single operating handle assembly


28


of the circuit breaker pole is advantageously tied to the two circuit breaker mechanisms


24


,


26


(through first and second secondary pivots


158


,


160


as discussed below) by the links


30


,


32


, respectively. In the exemplary embodiment, the two circuit breaker mechanisms


24


,


26


are housed in series in the single pole molded case


8


and are arranged for operation in the same direction, with the “load” side of the first mechanism


24


being electrically connected to the “line” side of the downstream second mechanism


26


. Thus, the upstream mechanism


24


provides the line terminal


16


of this pole and the downstream mechanism


26


provides the load terminal


10


of the pole.




The first and second links


30


,


32


engage the first and second operating mechanisms


36


,


42


to move the first and second separable contacts


34


,


40


, respectively, between the corresponding closed and open positions thereof responsive to the ON and OFF positions, respectively, of the operating handle assembly


28


.




Disposed within the molded case


8


are first and second arc chutes


46


,


48


, which are operatively associated with the first and second separable contacts


34


,


40


, respectively. The first set of separable contacts


34


includes a fixed contact


50


and a movable contact


52


. Similarly, the second set of separable contacts


40


includes a fixed contact


54


and a movable contact


56


. The first arc chute


46


is operatively associated with a first arc runner


58


extending from the first fixed contact


50


.




Similarly, the second arc chute


48


is operatively associated with a second arc runner


60


extending from the second fixed contact


54


, and a third arc runner


62


, which is electrically interconnected (through a bimetal element


70


as discussed below) with the load terminal


10


. A fourth arc runner


64


is operatively associated with and provides an electrically conducting path between the two arc chutes


46


,


48


.




The circuit breaker mechanisms


24


,


26


are provided within the molded case


8


for interconnection between the line terminal


16


and the load terminal


10


as discussed below. The first circuit breaker mechanism


24


includes the first fixed contact


50


and the first movable contact


52


, and the second circuit breaker mechanism


26


includes the second fixed contact


54


and the second movable contact


56


. The fixed contacts


50


,


54


are preferably welded on the arc runners


58


,


60


, respectively.




The exemplary first and second trip mechanisms


38


,


44


include magnetic trip coils


66


,


68


, respectively, to provide corresponding instantaneous magnetic trip functions. Although two trip coils


66


,


68


are shown, the invention is applicable to circuit breakers employing a single trip coil (not shown). Also, the second trip mechanism


44


further includes the bimetal element


70


to provide a thermal trip function. The bimetal element


70


has an input or free end


72


electrically interconnected by a flexible shunt


74


with the second movable contact


56


through a corresponding second movable contact arm


76


. The bimetal element


70


also has an output or base


77


, which is electrically interconnected by a flexible shunt


78


with a load conductor


80


of the load terminal


10


. Another flexible shunt


82


electrically connects a first movable contact arm


84


to the fourth arc runner


64


and to the input of the second magnetic trip coil


68


. Preferably, the bimetal element


70


also includes an adjustment screw


83


to adjust a thermal trip threshold thereof. The movable contacts


52


,


56


are suitably plated (e.g., silver) on the respective movable contact arms


84


,


76


, which are movably operable relative to the respective fixed contacts


50


,


54


depending on the status of the corresponding circuit breaker mechanisms


24


,


26


. The movable contact arm


76


, for example, has the movable contact


56


adapted for engagement with the corresponding fixed contact


54


. Similarly, the movable contact arm


84


has the movable contact


52


adapted for engagement with the corresponding fixed contact


50


.




Both of the magnetic trip coils


66


,


68


are preferably active and provide instantaneous magnetic trip functions for the respective circuit breaker mechanisms


24


,


26


. In this manner, the most effective current limiting capability is provided. Since the magnetic trip coils


66


,


68


act independently and since common activation currents are very difficult to achieve, a common trip actuator


206


(

FIG. 7

) is employed between the two circuit breaker mechanisms


24


,


26


.




Although the exemplary embodiment employs a single bimetal element


70


with the second circuit breaker mechanism


26


, a bimetal element (not shown) may alternatively be employed with the first circuit breaker mechanism


24


. Although one bimetal element is preferred, two bimetal elements (not shown) may be employed with both circuit breaker mechanisms


24


,


26


.




The first magnetic trip coil


66


is electrically interconnected between the line terminal


16


and the first fixed contact


50


by a line conductor


86


of the line terminal


16


at one end and the first arc runner


58


at the other end of the coil


66


. The second magnetic trip coil


68


is electrically interconnected between the first movable contact


52


and the second fixed contact


54


by the flexible shunt


82


at one end and the second arc runner


60


at the other end of the coil


68


.




An electrical circuit between the line terminal


16


and the load terminal


10


is formed by the series combination of the line conductor


86


from the line terminal


16


, the first magnetic trip coil


66


, the first arc runner


58


, the first fixed contact


50


, the first movable contact


52


(in the closed position of FIG.


5


), the first movable contact arm


84


, the flexible shunt


82


, the second magnetic trip coil


68


, the second arc runner


60


, the second fixed contact


54


, the second movable contact


56


(in the closed position of FIG.


5


), the second movable contact arm


76


, the flexible shunt


74


, the bimetal element


70


, the flexible shunt


78


, and the load conductor


80


to the load terminal


10


.




The first arc chute


46


is electrically positioned between: (a) the arc runner


58


for the first fixed contact


50


at the output of the first magnetic trip coil


66


, and (b) the arc runner


64


and the input of the second magnetic trip coil


68


. The second arc chute


48


is electrically positioned between: (a) the arc runner


60


for the second fixed contact


54


at the output of the second magnetic trip coil


68


, and (b) the arc runner


62


and the output or base


77


of the bimetal element


70


. The arc chutes


46


,


48


include a plurality of conventional spaced deionization plates


88


,


90


.




The exemplary circuit breaker


2


, thus, employs a series arrangement of the two circuit breaker mechanisms


24


,


26


. The interruption performance of the circuit breaker


2


is determined by the “current limitation of series arcs,” which provides two arcs in series, thereby having twice the resistance of a single arc. In the exemplary embodiment, IEC 898 component circuit breaker mechanisms are employed. This exemplary configuration allows for a UL 480 VAC (and perhaps a 600 VAC) device capable of 65 kA interruption in an 18 mm per pole width.




The enhanced current limiting capability provided by the circuit breaker


2


increases the likelihood for Type 2 protection. Such protection provides that equipment so classified can be returned to regular service after exposure to its listed short circuit withstand. No part or component within the system requires replacement prior to continued operation.




Also referring to

FIG. 3

, the operating handle assembly


28


includes an operating handle


92


(

FIG. 2A

) and a blocking disk


94


(FIG.


3


), both of which are co-pivotally mounted by a pivot mechanism


96


related to the molded base


4


. The secondary pivots


158


,


160


include a spring (not shown) which biases the operating handle


92


toward the OFF position of FIG.


2


A. The blocking disk


94


is preferably molded to include a first portion


98


and a second portion


100


. The first portion


98


(and, thus, the second portion


100


and the blocking disk


94


) is biased to resist counter-clockwise rotation with respect to

FIGS. 2A-2B

and


3


. The bias may be provided by employing cantilever spring member


102


having a first end


104


disposed from the first blocking disk portion


98


and a second end


106


loaded against a surface


108


of the molded base


4


. Alternatively, a torsion spring (not shown) may be employed.




The operating mechanisms


36


,


42


further include carrier mechanisms


110


,


112


, respectively. As shown in

FIGS. 6A-6C

, the carrier mechanism


110


of the first operating mechanism


36


includes a base portion


114


and a cover portion


116


. The base and cover portions


114


,


116


are secured together by two sets of fingers


118


,


120


of the base portion


114


, which engage the cover portion


116


at respective openings


122


,


124


thereof. The movable contact arm


84


is pivotally mounted to the carrier mechanism


110


by pivots


125


and


126


, which are pivotally mounted in an opening


128


of the base portion


114


and an opening


129


of the cover portion


116


, respectively.




The carrier mechanism


110


also includes a latch member


130


and a spring


132


. The latch member


130


is pivotally mounted to the carrier mechanism


110


by a post


134


, an upper end of which extends through an opening


136


of the cover portion


116


. A lower end


135


(shown in

FIGS. 4 and 5

) of the post


134


extends through a corresponding opening


135


A (shown in

FIGS. 4 and 5

) of the carrier base portion


114


. In turn, the lower post end


135


is pivotally mounted in an opening (not shown) of the molded base


4


of FIG.


3


. The carrier mechanism


110


further includes a channel


137


formed in the base portion


114


and the cover portion


116


. The channel


137


has a first end


138


and an opposite second end


140


. As discussed below, the pivotally mounted latch member


130


is employed for releasing the carrier mechanism


110


in response to a trip condition of the circuit breaker


2


.




As shown in

FIGS. 2A-2B

, the channel


137


accepts a U-shaped link


142


with an end


143


being disposed in the first end


138


of the channel


137


of the first carrier mechanism


110


. Similarly, a U-shaped link


144


having an end


145


is disposed in the first end


138


of the channel


137


of the second carrier mechanism


112


. As discussed below, the links


142


,


144


provide linkages from the respective carrier mechanisms


110


,


112


through the secondary pivots


158


,


160


to the operating handle assembly


28


.




Referring again to

FIGS. 6A-6C

, the spring


132


has an opening


146


, a first end


148


and a second end


150


. The post


134


of the latch member


130


passes through the spring opening


146


. A bend portion


149


proximate the first spring end


148


engages a notch


152


of the carrier base portion


114


, and the second spring end


150


engages a surface


153


of the movable contact arm


84


in order to bias such arm clockwise with respect to FIG.


6


C. The link


142


is engaged by the hook member


156


of the latch member


130


, which permits the carrier mechanism


110


to rotate with the operating handle assembly


28


. The carrier spring


132


further interacts with the molded base


4


to provide counterclockwise (with respect to

FIG. 2A

) bias to open the carrier mechanism


110


upon release of the latch member


130


.




A spring (not shown) associated with the secondary pivot


160


(

FIG. 2B

) biases the operating handle


92


off and biases the upper portion of the latch member


130


clockwise (with respect to

FIG. 6A

) to hold the link end


143


in the first end


138


of the channel


137


. As discussed below, the latch member


130


is adapted to pivot counter-clockwise with respect to

FIG. 6A

in response to a trip condition to release the link end


143


toward the second end


140


of the channel


137


. Hence, the latch member


130


releases the link


142


in response to a trip condition.




Referring to

FIGS. 2A-2B

and


3


-


5


, the operating handle


92


has an OFF position (FIG.


2


A), an ON position (shown in phantom line drawing in FIG.


2


A), and first and second intermediate positions (shown in

FIGS. 3 and 4

, and

FIG. 5

) between the OFF and ON positions. As shown in

FIGS. 2A

,


4


and


5


, the operating handle assembly


28


is rotated counter-clockwise (with respect to

FIG. 2A

) toward the ON position (as shown in phantom line drawing in FIG.


2


A). The operating handle assembly


28


, in turn, drives the operating mechanisms


36


,


42


through the links


30


,


32


, which rotate the secondary pivots


158


,


160


, respectively, counter-clockwise (with respect to FIGS.


2


A-


2


B). The pivots


158


,


160


are pivotally mounted to the molded base


4


by respective pins


162


,


164


. The opposite secondary pivot ends


163


,


165


of the links


142


,


144


are pivotally mounted in openings of the pivots


158


,


160


, respectively. Similarly, first ends of the links


30


,


32


are pivotally mounted in corresponding openings of the operating handle assembly


28


, and second ends of the links


30


,


32


are pivotally mounted in corresponding openings of the respective pivots


158


,


160


.




As shown with the operating mechanism


36


, the first secondary pivot


158


, in turn, drives the link


142


, which drives the carrier mechanism


110


clockwise (with respect to

FIG. 2A

) about the post


134


. As discussed above in connection with

FIGS. 6A-6C

, the carrier mechanism


110


carries the movable contact arm


84


having the movable contact


52


disposed at the free end thereof. Solely with this arrangement, as disclosed above, the slower that the user rotates the operating handle assembly


28


into the ON position, the slower the carrier mechanism


110


drives the movable contact arm


84


, in order to contact the fixed contact


50


with the movable contact


52


. It will be appreciated that the second operating mechanism


42


, the second secondary pivot


160


, the links


32


and


144


, the second carrier mechanism


112


, and the second separable contacts


40


operate in an analogous manner.




A pivot lever


166


is pivotally mounted to the molded base


4


by a pin


168


. The pivot lever


166


includes a first arm


169


having a first end


170


adapted for engagement with the movable contact arm


84


, and a second arm


171


having a second end


172


adapted for engagement with the operating handle assembly


28


. The first end


170


of the pivot lever


166


carriers a U-shaped hook member


174


pivotally disposed thereon. The hook member


174


has a J-shaped hook


176


(shown in FIG.


3


), which hook is adapted for engagement with the movable contact arm


84


, and a J-shaped pivot end


178


, which is pivotally mounted in an opening


179


of the first arm


169


.




In order to eliminate the dependency between the movable contact arm


84


and the operating handle assembly


28


, the hook


176


of the hook member


174


initially hooks the movable contact arm


84


(as shown in FIG.


4


). The pivot end


178


of the hook member


174


is inserted into the first or free end


170


of the pivot lever


166


. The pivot lever


166


pivots about the pin


168


and translates the hook member


174


and the movable contact arm


84


movement up to the operating handle assembly


28


. The second or handle end


172


of the pivot lever


166


interacts with the blocking disk


94


(

FIG. 5

) of the operating handle assembly


28


, which disk rotates about the same center as the operating handle


92


, but is allowed independent movement.




This independent movement of the operating handle


92


and the blocking disk


94


of the operating handle assembly


28


provides a resettable snap close function. As shown in

FIGS. 3 and 4

, the blocking disk


94


includes two diameters or surfaces


180


,


182


having an abrupt radius transition or surface


184


therebetween. The blocking disk


94


is continuously biased clockwise (with respect to

FIGS. 2A and 3

) and counter-clockwise (with respect to

FIGS. 4 and 5

) by the spring


102


. This forces the large diameter


182


to block the handle end


172


of the pivot lever


166


from clockwise rotation (with respect to

FIGS. 2A and 3

, and, thus, from counter-clockwise rotation with respect to FIG.


4


). As shown in the blocking position of

FIG. 4

, the pivot lever


166


and the hook member


174


block the movable contact arm


84


from rotating with the carrier mechanism


110


as the operating handle assembly


28


is turned (clockwise with respect to

FIG. 4

) to the ON position of the operating handle


92


(shown in phantom line drawing in FIG.


4


).




As shown in

FIGS. 4 and 5

, this blocking condition (

FIG. 4

) exists until the operating handle assembly


28


is further turned clockwise (with respect to

FIG. 5

) toward the ON position of the operating handle


92


(shown in phantom line drawing in FIG.


5


), at which time the blocking disk


94


is forced to rotate with the operating handle assembly


28


by the dowel or extension


186


(

FIG. 4

) of the operating handle


92


, which dowel engages the radius or surface


188


of the blocking disk


94


. As the blocking disk


94


is rotated further counter-clockwise with respect to

FIGS. 2A and 3

by the operating handle dowel


186


, the blocking disk


94


rotates clockwise with respect to

FIGS. 4 and 5

against the bias of the spring


102


. As shown in

FIG. 5

, this rotation causes the large diameter


182


of the blocking disk


94


to abruptly transition to the smaller diameter


180


at the end portion


190


of the handle end


172


of the pivot lever


166


.




The line of force exerted through the drive lines


142


,


144


on the respective secondary pivots


158


,


160


passes through the pivot center of such pivots as the operating handle


92


approaches the ON position. The previous clockwise bias (with respect to

FIGS. 2A-2B

) of the secondary pivots


158


,


160


changes to a counterclockwise bias (with respect to FIGS.


2


A-


2


B), which tends to keep the operating handle


92


, as connected through the links


142


,


144


, in the ON position.




The first surface or large diameter


182


of the blocking disk


94


blocks the end


190


of the pivot lever


166


as the operating handle assembly


28


is moved from the OFF position (

FIG. 2A

) toward the intermediate non-blocking position (

FIG. 5

) thereof. That large diameter


182


releases the pivot lever end


190


to the second surface or small diameter


180


as the operating handle assembly


28


is moved to the intermediate position (

FIG. 5

) thereof. As shown in

FIG. 4

, the hook member


174


of the pivot lever


166


blocks movement of the movable contact arm


84


when the large diameter


182


blocks the pivot lever end


190


. In turn, the hook member


174


of the pivot lever


166


releases (

FIG. 5

) the movable contact arm


84


when the large diameter


182


releases the pivot lever end


190


as the operating handle assembly


28


is moved to the intermediate position (

FIG. 5

) thereof, thereby allowing movement of the movable contact arm


84


and the movable contact


52


toward the fixed contact


50


in response to the bias of the carrier mechanism spring


132


(FIGS.


6


A-


6


C).




As shown in

FIG. 5

, once the abrupt radius transition


184


rotates past the end portion


190


to the recessed portion


192


of the pivot lever handle end


172


, the pivot lever


166


is, then, allowed sufficient counter-clockwise (with respect to

FIG. 5

) motion and the movable contact arm


84


, which was previously held stationary by the hook member


174


, snaps to close the movable contact


52


onto the fixed contact


50


. During the blocking operation (FIG.


4


), the movable contact arm


84


pivots counter-clockwise (with respect to

FIGS. 6A-6C

) in the carrier mechanism


110


and, thus, the closing force for the separable contacts


34


is directed clockwise with respect to

FIG. 2A

(and counter-clockwise with respect to

FIG. 5

) due to the carrier spring


132


.




In the exemplary embodiment, the snap close function (from

FIG. 4

to

FIG. 5

) is provided with the hook member


174


, the carrier mechanism


110


and the movable contact arm


84


. Since no blocking function is provided with the exemplary second carrier mechanism


112


and its movable contact arm


76


, the second separable contacts


40


close before the first separable contacts


34


.




As the circuit breaker


2


is turned OFF or trips open, the dowel


186


(

FIG. 4

) of the operating handle


92


rotates the pivot lever


166


(clockwise with respect to

FIG. 4

) to clear the large diameter


182


of the blocking disk


94


. Once this has occurred (FIG.


4


), the bias (shown as counter-clockwise in

FIG. 4

) of the spring


102


drives the blocking disk


94


back to its original position (FIG.


3


), thereby resetting it for another close operation.




The interaction between the operating handle assembly


28


and the pivot lever


166


also advantageously acts as a position ON indication. In the event that the separable contacts


50


,


52


have welded closed, when turning the operating handle


92


to the OFF position, the pin


186


(

FIG. 4

) engages the second arm


171


of the pivot lever


166


, which is prevented from rotating through hook member


174


. Hence, it is not possible to bring the operating handle assembly


28


back to the position of

FIG. 4

without the application of excessive force.





FIG. 7

shows the circuit breaker


2


of

FIG. 1

constructed by stacking three single pole circuit breakers


200


,


202


,


204


, which employ two trip actuators


206


,


208


therebetween. The circuit breakers


202


,


204


are preferably identical to the circuit breaker


200


as discussed in connection with

FIGS. 2A-2B

,


3


-


5


,


6


A-


6


C and


9


herein. As shown in

FIG. 8

, each of these trip actuators, as shown with actuator


206


, has a push-to-trip pushbutton


210


, which is engaged by one of the trip actuators


206


,


208


of FIG.


7


. The push-to-trip pushbutton


210


is disposed through an opening


212


formed between adjacent molded bases


4


of the single pole circuit breakers


200


,


202


. The trip actuator


206


extends toward the face of the exemplary circuit breaker


2


and engages the manual trip button


210


(

FIG. 8

) to facilitate manual trip testing.




Referring again to

FIG. 2A

, the latch member


130


of the carrier mechanism


110


is adapted to pivot (counter-clockwise with respect to

FIG. 2A

) in response to various trip conditions, in order to release the end


143


of the link


142


toward the second end


140


of the carrier channel


137


and, thus, trip the circuit breaker mechanism


24


and, in turn, the circuit breaker


2


. As shown in

FIG. 6A

, the upper end projection


214


of the latch member


130


of circuit breaker


202


is adapted for engagement by a projection


216


(shown in phantom line drawing in

FIG. 6A

) of the trip actuator


206


, which is external to the circuit breakers


200


,


202


of FIG.


7


. In a related manner, an upper end projection


242


(

FIG. 2B

) of the latch member


220


of the second carrier mechanism


112


of circuit breaker


202


is adapted for engagement by a projection


222


(

FIG. 7

) of the trip actuator


206


.




Referring to

FIGS. 7 and 9

, the upper end


215


of the latch member


220


of the second carrier mechanism


112


is adapted for engagement by a projection


219


of the trip actuator


206


. In a related manner, the upper end


218


of the latch member


130


of the first carrier mechanism


110


is adapted for engagement by a projection


217


of the trip actuator


206


. Manual movement (as shown by arrow


224


of the push-to-trip pushbutton


210


from the left to the right of

FIG. 9

) (i.e., from the bottom right to the top left of

FIG. 8

as shown by arrow


226


) rotates the latch members


130


,


220


clockwise (with respect to

FIG. 9

, and counter-clockwise with respect to

FIG. 6A

for latch member


130


). For example, in the first circuit breaker mechanism


24


, the hook member


156


of the latch member


130


releases the link end


143


. In turn, the carrier mechanism


110


rotates clockwise (with respect to

FIG. 5

, and counter-clockwise with respect to

FIG. 6A

) under the bias of spring


132


and the link end


143


(

FIG. 2A

) moves toward the second end


140


of the channel


137


.




As shown in

FIG. 2A

, the lower end


228


of the first latch member


130


is adapted for engagement by the armature


230


of the first coil


66


of the first magnetic trip circuit. Under predetermined instantaneous current conditions (e.g., greater than about three, seven or twenty times rated current), the current flowing through the coil


66


, from the line terminal


16


to the load terminal


10


, causes the armature


230


to move to the right on

FIG. 2A

, engage the lower end


228


of the latch member


130


, and rotate the latch member


130


counter-clockwise (with respect to

FIGS. 2A and 6A

, and clockwise with respect to FIG.


9


). In a related manner, the lower end


232


of the second latch member


220


is adapted for engagement by the armature


234


of the coil


68


of the second magnetic trip circuit.




As shown in

FIG. 3

, the bottom end


236


of the second latch member


220


is adapted for engagement by a shuttle member


238


of the bimetal element


70


of the thermal trip circuit. Under thermal trip conditions, the free end


72


of the bimetal element


70


moves to the right of FIG.


3


. In response, the shuttle member


238


, which engages the bottom end


236


of the second latch member


220


, rotates the latch member


220


counter-clockwise (with respect to FIGS.


2


B and


3


), in order to trip the second circuit breaker mechanism


26


.




As shown in

FIG. 9

, the trip actuator


206


includes the projections


216


and


222


, which respectively engage the upper end projection


214


of the first latch member


130


of the first circuit breaker mechanism


24


and the corresponding upper end projection


242


(shown in

FIG. 2B

) of the second latch member


220


of the second circuit breaker mechanism


26


of the circuit breaker


202


. Similarly, the second trip actuator


208


includes projections


244


,


246


, which engage the upper end projections (not shown) of the latch members (not shown) of the two circuit breaker mechanisms (not shown) of the third circuit breaker


204


of FIG.


7


.




As shown in

FIG. 7

, the circuit breaker


200


is adapted for operation as a first pole of the circuit breaker


2


. The trip actuator


206


includes the projections


217


,


250


and


219


,


252


, which are adapted to interface the two carrier mechanisms


110


,


112


of the first pole formed by the circuit breaker


200


. The trip actuator


206


also includes the projections


216


,


222


, which are adapted to interface the two carrier mechanisms (not shown) of the second pole formed by the circuit breaker


202


. It will be appreciated that the second trip actuator


208


operates in an analogous manner with respect to the other two adjacent circuit breakers


202


,


204


.




The projections


216


,


222


,


244


,


246


of the trip actuators


206


,


208


cooperate with the four carrier mechanisms


110


,


112


of the circuit breakers


202


,


204


, in order to provide a cascading trip of the four sets of separable contacts


34


,


40


. For example, in response to a thermal trip, magnetic trip or manual trip of the circuit breaker mechanism


24


of the circuit breaker


202


, the carrier mechanism


112


rotates clockwise (with respect to

FIG. 5

, and counter-clockwise with respect to FIG.


6


A). As shown in

FIG. 6A

, the cover portion


116


of the carrier mechanism


112


of the circuit breaker


202


has a projection


248


, which engages the projection


216


(shown in phantom line drawing) of the trip actuator


206


. In turn, movement of the trip actuator


206


(toward the upper left of

FIG. 7

) causes the projection


222


to engage the upper end projection


242


(shown in

FIG. 2B

) of the second latch member


220


and, thereby, trip the second circuit breaker mechanism


26


of the circuit breaker


202


.




The trip actuators


206


and


208


also include respective projections


217


,


219


(as discussed above in connection with

FIG. 9

) and


221


,


223


, which cooperate with the four carrier mechanisms


110


,


112


of the circuit breakers


200


,


202


, in order to manually cause the cascading trip of the four sets of separable contacts


34


,


40


.




The trip actuators


206


and


208


further include respective finger projections


250


,


252


and


254


,


256


, which cooperate with the four carrier mechanisms


110


,


112


of the circuit breakers


200


,


202


, in order to provide the cascading trip of the four sets of separable contacts


34


,


40


. As shown in

FIG. 9

, in response to a thermal trip, magnetic trip or manual trip of the first circuit breaker mechanism


24


of the circuit breaker


200


, the carrier mechanism


112


rotates clockwise (with respect to

FIG. 9

, and counter-clockwise with respect to FIG.


6


A). This causes the movement of the trip actuator


206


to the right of

FIG. 9

as shown by the arrow


224


.




In turn, the movement of the projection


219


moves the upper portion


215


of the latch member


220


, which causes the trip of the circuit breaker mechanism


26


of the circuit breaker


200


. Also, the movement of the projections


216


and


222


respectively moves the upper end projection


214


of the latch member


130


of the first circuit breaker mechanism


24


and the upper end projection


242


of the latch member


220


of the second circuit breaker mechanism


26


of the circuit breaker


202


. Further, the circuit breaker


202


causes the movement of the trip actuator


208


through the projections


254


,


256


, thereby moving the projections


244


,


246


to cause the trip of the circuit breaker mechanisms


24


,


26


, respectively, of circuit breaker


204


.




Thus, as discussed above, a manual or magnetic trip of one of the six circuit breaker mechanisms


24


,


26


(or a thermal trip of one of the three circuit breaker mechanisms


26


) of the circuit breakers


200


,


202


,


204


causes the trip of the other five circuit breaker mechanisms.




While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of invention which is to be given the full breadth of the claims appended and any and all equivalents thereof.



Claims
  • 1. A circuit breaker comprising:a housing; line and load terminals; a first circuit breaker mechanism comprising: a first set of separable contacts, a first operating mechanism for moving said first set of separable contacts between an open position and a closed position, and a first trip mechanism cooperating with said first operating mechanism for moving said first set of separable contacts from said closed position to said open position thereof; a second circuit breaker mechanism comprising: a second set of separable contacts in series with said first set of separable contacts between said line and load terminals, a second operating mechanism for moving said second set of separable contacts between an open position and a closed position, and a second trip mechanism cooperating with said second operating mechanism for moving said second set of separable contacts from said closed position to said open position thereof; an operating handle having an on position and an off position; a first link from said operating handle to said first operating mechanism; and a second link from said operating handle to said second operating mechanism, wherein said first and second links engage said first and second operating mechanisms to move said first and second sets of separable contacts, respectively, between said corresponding closed and open positions thereof responsive to the on and off positions, respectively, of said operating handle.
  • 2. The circuit breaker of claim 1 wherein said housing has first and second arc chutes operatively associated with said first and second sets of separable contacts, respectively.
  • 3. The circuit breaker of claim 2 said first and second arc chutes are operatively associated with an arc runner extending between said arc chutes.
  • 4. The circuit breaker of claim 3 wherein said second trip mechanism includes a bimetal element in order to provide a thermal trip function; wherein said second set of separable contacts includes a fixed contact and a movable contact; and wherein said bimetal element is electrically interconnected with said movable contact.
  • 5. The circuit breaker of claim 3 wherein said first and second trip mechanisms include a magnetic trip coil in order to provide an instantaneous magnetic trip function; wherein said first and second sets of separable contacts include a fixed contact and a movable contact; wherein the magnetic trip coil of said first trip mechanism is electrically interconnected between the line terminal and the fixed contact of said first set of separable contacts; and wherein the magnetic trip coil of said second trip mechanism is electrically interconnected between the movable contact of said first set of separable contacts and the fixed contact of said second set of separable contacts.
  • 6. The circuit breaker of claim 5 wherein said first arc chute is operatively associated with a first arc runner extending from the fixed contact of said first set of separable contacts; and wherein said second arc chute is operatively associated with a second arc runner extending from the fixed contact of said second set of separable contacts and a third arc runner which is electrically interconnected with said load terminal.
  • 7. The circuit breaker of claim 6 wherein said second trip mechanism includes a bimetal element in order to provide a thermal trip function; and wherein said bimetal element has an input electrically interconnected with the movable contact of said second set of separable contacts and an output which is electrically interconnected with the load terminal.
  • 8. The circuit breaker of claim 1 wherein said second trip mechanism includes a bimetal element in order to provide a thermal trip function.
  • 9. The circuit breaker of claim 1 wherein said first and second trip mechanisms include a magnetic trip coil in order to provide an instantaneous magnetic trip function.
  • 10. The circuit breaker of claim 9 wherein one of said first and second operating mechanisms includes a trip actuator which cooperates with the other of said first and second operating mechanisms, in order to simultaneously trip open both of said first and second sets of separable contacts.
  • 11. The circuit breaker of claim 10 wherein said housing includes an opening having a trip test button proximate thereto; and wherein said trip actuator includes a member, which extends toward the opening and engages said button.
  • 12. The circuit breaker of claim 10 wherein said circuit breaker is adapted for operation as a first pole; and wherein said trip actuator includes a member which is adapted to interface another operating mechanism of a second pole.
  • 13. The circuit breaker of claim 12 wherein said first and second operating mechanisms include first and second latch members for releasing said first and second operating mechanisms, respectively, to the open position.
  • 14. The circuit breaker of claim 13 wherein one of said first and second operating mechanisms includes a trip actuator having a first extension which engages the first latch member to release said first operating mechanism, and having a second extension which engages the second latch member to release said second operating mechanism.
  • 15. The circuit breaker of claim 14 wherein said trip actuator further has third and fourth extensions which are adapted to release first and second operating mechanisms, respectively, of the second pole.
  • 16. The circuit breaker of claim 1 wherein said first and second operating mechanisms include first and second latch members for releasing said first and second operating mechanisms, respectively, to the open position.
  • 17. The circuit breaker of claim 16 wherein one of said first and second operating mechanisms includes a trip actuator having a first extension which engages the first latch member to release said first operating mechanism, and having a second extension which engages the second latch member to release said second operating mechanism.
  • 18. The circuit breaker of claim 1 wherein said housing encloses both of said first and second circuit breaker mechanisms.
CROSS-REFERENCE TO RELATED APPLICATION

This application is related to commonly assigned, concurrently filed U.S. patent application Ser. No. 10/185,858, filed Jun. 27, 2002, entitled “Circuit Breaker”.

US Referenced Citations (6)
Number Name Date Kind
5043687 Gibson Aug 1991 A
5301083 Grass et al. Apr 1994 A
5373411 Grass et al. Dec 1994 A
5541561 Grunert et al. Jul 1996 A
5606299 Innes et al. Feb 1997 A
6472621 Merlin et al. Oct 2002 B2