Magnetic release, in particular for a circuit breaker, and a circuit breaker having such a magnetic release

Information

  • Patent Grant
  • 6525632
  • Patent Number
    6,525,632
  • Date Filed
    Tuesday, September 4, 2001
    23 years ago
  • Date Issued
    Tuesday, February 25, 2003
    21 years ago
Abstract
A magnetic release is described for an electrical switching device, such as a circuit breaker, which has a coil, a core located inside the coil, and an armature in the form of a plunger-type armature which can move inside the coil or in the form of a hinged armature. The coil is stamped and bent from sheet metal composed of an electrically highly conductive material. It has first webs that are located at a distance from one another in a first plane and second webs that are likewise located at the same distance from one another in a second plane. The webs each run parallel to one another and are offset with respect to one another in such a manner that the webs are disposed with connecting webs in a helical shape around a center axis, and on the inside form a through-opening for accommodating at least one core.
Description




BACKGROUND OF THE INVENTION




FIELD OF THE INVENTION




The invention relates to a magnetic release for a switching device in particular for a circuit breaker. The magnetic release has a coil, a core located inside the coil and an armature that may be in the form of a plunger-type armature moving inside the coil or in the form of a hinged armature.




A magnetic release, in particular for a circuit breaker, contains a coil which is produced from wire wound in a helical shape, a magnet core which is firmly connected to a yoke surrounding the coil on the outside and which engages in the interior of the coil, and a magnet armature which is either in the form of a hinged armature or a plunger-type armature, with the latter likewise being located inside the coil. In one known configuration, the core and the armature are located inside a cylindrical tube, with the armature being held at a distance from the core by a compression spring, so that the armature is attracted towards the core, against the force of the spring, when an overcurrent or short-circuit current is present. At one end, the coil is connected to the yoke, which at that point has a holder for a thermal bimetallic strip and at the other end is fitted with a stationary contact piece, which merges into an arc guide rail which bounds an arc splitter stack on the release side and feeds the base of the arc which is produced on the stationary contact piece to the arc splitter stack.




In a configuration such as this, an insulated wire composed of copper must be stripped and wound into a helical shape at the ends in order to produce the coil, which involves the use of a large amount of labor time. Furthermore, the coil must also have an associated yoke, to which the coil tube is fitted, and around which the insulated wire is wound and is guided in the armature and core. Production of this configuration is costly.




SUMMARY OF THE INVENTION




It is accordingly an object of the invention to provide a magnetic release, in particular for a circuit breaker, and a circuit breaker having such a magnetic release that overcomes the above-mentioned disadvantages of the prior art devices of this general type, whose manufacture is simplified.




With the foregoing and other objects in view there is provided, in accordance with the invention, a magnetic release for an electrical switching device. The magnetic release contains a coil being stamped and bent from sheet metal composed of a material being electrically highly conductive and magnetically highly permeable. The coil has first webs disposed at a given distance from one another in a first plane and second webs disposed at the given distance from one another in a second plane and in each case run parallel to one another and offset with respect to one another. The coil has connecting webs in each case disposed between one end of one of the first webs and an adjacent end of one of the second webs and in each case one end of one of the second webs and an adjacent end of one of the first webs. The first webs, the second webs and the connecting webs are disposed in such a manner that the first webs, the second webs and the connecting webs are in a helical shape around a center axis. The first webs, the second webs and the connecting webs define an inside region in a form of a through-opening, the coil additionally having a stationary contact piece of a contact point for a circuit breaker. A holder for a thermal release is integrally formed on the coil and a core is accommodated in the through opening of the coil. An armature of a plunger-type armature moving inside the coil or a hinged armature is provided.




According to a further refinement of the invention, an arc guide rail for an arc splitter stack is then integrally formed on the stationary contact piece. An arc splitter stack, for quenching, is integrally formed on the arc guide rail, inside the electrical switching device.




In addition, a core can also be integrally formed on the coil. More specifically, an L-shaped lug can be integrally formed at one end on the coil, the L-shaped lug having a free limb projecting into a coil area on its center axis, and forms the core.




The coil, the stationary contact piece, the arc guide rail and the holder for the thermal release, possibly together with the core, thus form a unit. There is no longer any need for wire windings. Since the coil is formed from sheet iron, there is likewise no longer any need for an autonomous yoke.




A coil as such, without a stationary contact piece, arc guide rail and holder for the thermal release, has been disclosed per se in German Patent DE 6 66 920. The coil is essentially used as a field coil for synchronized machines or direct-current machines, to be precise in order to replace the flat conductors, wound on edge.




Such a refinement of the coil can be produced easily by stamping from a metal sheet and by folding and bending, so that there is no longer any need for special winding apparatuses with a winding mandrill or the like.




According to a further embodiment, the first and second webs are U-shaped, with the U-shape of the first and second webs each being open towards the opposite plane.




The connecting webs can then advantageously be connected alternately at one end of each web to one limb of the U-shape and at the other end to the other limb of the U-shape.




This results in a concertina-like coil which is stamped and bent in a helical shape from sheet metal composed of a material which is electrically highly conductive and magnetically highly permeable, in which case there is no need to coat the sheet metal with an insulating material, since the individual turns do not touch one another.




In accordance with an added feature of the invention, the connecting webs each assume an angle to one another, and one of the connecting webs runs parallel to another, over others of the connecting webs. The connecting webs can also run parallel to one another at right angles to the center axis.




A circuit breaker can be formed of the magnetic release as described above. The circuit breaker has a housing with inner surfaces, mutually opposite ones of the inner surfaces have strips that engage between coil turns in order to guide the coil.




In accordance with a further feature of the invention, the strips are configured such that they are used to guide the core and/or the armature.




In accordance with a concomitant feature of the invention, an arc guide rail is integrally formed on the coil. The core, the stationary contact piece and the arc guide rail are disposed at one end of the coil, and the holder for the thermal release is disposed at another end of the coil.




Other features which are considered as characteristic for the invention are set forth in the appended claims.




Although the invention is illustrated and described herein as embodied in a magnetic release, in particular for a circuit breaker, and a circuit breaker having such a magnetic release, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.











The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.




BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a diagrammatic plan view of a coil according to the invention, without a stationary contact piece, arc guide rail or holder for a thermal bimetallic strip;





FIG. 2

is an illustration of the coil in the direction of the arrow II shown in

FIG. 1

;





FIG. 3

is an illustration of the coil in the direction of the arrow III shown in

FIG. 2

;





FIG. 4

is an illustration of a development of the coil, as shown in

FIGS. 1

to


3


, as a stamped sheet-metal part;





FIG. 5

is a side-elevational view of the coil with a stationary contact piece, the arc guide rail and the holder for a thermal bimetallic strip;





FIG. 6

is a plan view of a further refinement of the coil; and





FIG. 7

is a sectional view taken along the section line VII—VII shown in FIG.


6


.











DESCRIPTION OF THE PREFERRED EMBODIMENTS




In all the figures of the drawing, sub-features and integral parts that correspond to one another bear the same reference symbol in each case. Referring now to the figures of the drawing in detail and first, particularly, to

FIG. 5

thereof, there is shown side view of a coil


80


. A U-shaped extension


82


, whose open side


83


points towards the coil


80


, is integrally formed on a coil web


81


located at an upper end of the coil


80


in

FIG. 5. A

limb


84


of the U-shaped extension


82


which is immediately adjacent to the coil web


81


is fitted with a stationary contact piece, which is not illustrated in any more detail, for a circuit breaker, which stationary contact piece interacts with a moving contact piece


120


as illustrated, for example, in the case of the S


2


switching device from ABB Stotz-Kontakt GmbH. The limb


84


runs parallel to the coil web


81


, and a further limb


85


runs at an acute angle to the limb


84


and is adjacent to an arc guide rail


86


which runs parallel to a center axis M—M of the coil


80


. The arc guide rail


86


bounds an arc splitter stack


130


on the side adjacent to the coil


80


.




A coil web


87


of the coil


80


, which is located at the opposite end, at the lower end of the coil


80


in

FIG. 5

, has a bend


88


which runs at right angles thereto, and runs parallel to the center axis M—M, to be precise approximately in a plane E


1


, see also

FIG. 3. A

limb


89


of a holder


90


for a thermal bimetallic strip


100


is integrally formed on it. The thermal bimetallic strip


100


is fixed on the other, free limb


91


of the holder


90


. A lug


93


that runs parallel to the coil web


87


and interacts with the limb


91


is integrally formed at the junction point of the limb


88


and of the limb


89


. A threaded screw


94


is screwed through the limb


91


and its other end, as shown by the arrow P, rests against that surface of the lug


93


which is opposite the limb


91


, so that the distance between the lug


93


and the free end of the limb


91


can be varied to allow the thermal bimetallic strip


100


to be adjusted. Such a holder is also provided, per se, in the S


2


circuit breaker mentioned above.




As can be seen from

FIG. 5

, the coil


80


, the extension


82


with the stationary contact piece on the limb


84


, the arc guide rail


86


and the holder


90


for the thermal bimetallic strip


100


form a unit. The coil


80


contains an armature, which is not illustrated, and a core, which is firmly connected to the coil


80


and is likewise not illustrated, in which case the core may, for example, be integrally formed on or attached to the coil web


81


(see FIGS.


6


and


7


). If necessary, an armature guide tube (not illustrated in any more detail) can be provided for guiding the armature.




Since the coil is composed of magnetically permeable material, there is no longer any need for an autonomous yoke.




Let us now refer to

FIGS. 2 and 3

, in order to show how the coil


80


for the release can be produced.




The view in

FIG. 3

shows webs


10


,


11


and


12


. . . , which lie approximately in a plane, and with a distance D between them in each case being the same. A first plane is represented by the line E


1


. Parallel to the first plane, there is a second plane E


2


in which second webs


20


,


21


. . . are located, the distance between which is likewise equal to the distance D. The first and second webs


10


,


11


,


12


. . . ;


20


,


21


. . . run parallel to one another, are in each case disposed offset with respect to one another, and each have a U-shape, whose open sides


30


,


31


,


32


and


40


,


41


. . . , respectively, are each open towards the opposite plane. The web


10


is connected by an obliquely running connecting web


50


to the web


20


; at the opposite end, the web


20


is connected to the web


11


via a connecting web


51


, the web


11


is connected to the web


21


via a connecting web


52


at the opposite end, etc, so that this results in a coil which is disposed in a zig-zag shape, is wound around the center axis M—M, and is composed of the connecting webs, and the first and second webs. A connecting line


61


(

FIG. 2

) in the form of a wall is connected via a connecting web


60


to the first web


10


, and, for example, a fixing point for a thermal bimetallic strip can be fitted or integrally formed on the opposite last web.





FIG. 4

shows the bend in the sheet-metal shape after stamping but before folding, with the webs


10


,


11


and


12


. . . and the webs


20


,


21


. . . together with the connecting webs


60


,


50


,


51


,


52


. . . all lying in one plane.




In order to form the coil, the web


10


is bent along the bending line B, such that the U-shape points towards the plane of the drawing; the web


20


is bent along the bending line B


2


, so that the U-shape is open towards the viewer; the web


11


is bent once again so that the tip faces the viewer and the open U-shape faces the plane of the drawing, etc, so that only one bend along the bending line B


1


, B


2


, B


3


. . . is required to produce the coil.




It can be seen from

FIG. 3

that the connecting webs


50


,


51


,


52


,


60


each form an angle with one another. Depending on the number of turns which are required for an appropriate application, the connecting webs


50


,


51


,


52


. . . and the web


60


can run parallel to one another, in which case the U-shape can be configured to be polygonal or rounded with two parallel limbs.




The configuration of the individual connecting webs and connections is illustrated in

FIG. 1

, which shows a view in the direction of the arrow I in FIG.


2


. The special configuration, stamping and winding result in a coil being formed which surrounds an internal area


70


whose center axis corresponds to the center axis M, and a coil tube


71


can be inserted into the internal area or recess


70


in which, represented by dashed lines, a core


72


and an armature


73


are located. The coil tube


71


corresponds to the normal coil tubes as are present and are known in commercially available magnetic releases.




The material may be steel strip that is copper-plated on both sides in order to improve the electrical conductivity; such steel strips are commercially available.




The yoke that a magnetic release normally contains can be integrally formed on the coil


80


, by appropriate shaping of the supply line


61


, for example. At the same time, the core


72


can also be attached to the connecting conductor


61


, which could at the same time also be fitted with a stationary contact.




When the coil


80


is inserted into a housing, then projections are expediently provided on the inner surface of the housing and engage in the space in-between the individual webs


20


,


21


and


10


,


11


, in order to guide the coil


80


and in order to prevent the individual connecting webs


60


,


50


,


51


,


52


. . . being drawn towards one another when a short-circuit occurs, although this is not shown.




The armature


73


or the core


72


shown with a circular shape in

FIG. 1

may also be configured with a rectangular cross section; it can be guided in a coil sleeve, as illustrated, or in housing projections, which are provided on the guide strips or guide projections on the housing, in order to guide and hold the coil.




The invention is illustrated using a plunger-type armature magnetic release; it is, of course, also possible to configure the core such that it passes completely through the coil, and the armature may then also be in the form of a hinged armature. Since the coil is made of iron, it acts as a yoke. Copper-plated iron can be used for high current densities.




This results in a yoke, coil, stationary contact piece and thermal bimetallic strip fixing together with an arc guide rail of integral composition, which can be produced as stamped and bent material from sheet metal.




Let us now refer to

FIGS. 6 and 7

.




A coil


110


shown in

FIG. 6

is constructed and produced in the same way as the coil shown in

FIG. 1

; this can be seen from the reference numbers


10


,


11


,


12


. . . . ,


20


,


21


. . . . ,


51


. . .


61


. . .




If one considers the coil shown in

FIG. 5

, then a web


111


would be integrally formed on the web which is represented by the reference number


81


in FIG.


5


and also has the reference number


81


in

FIG. 7

, which web


111


projects into the area


71


inside the coil and is fitted at the inner end, approximately on the center line M—M (see FIG.


5


), with a limb


112


, which projects parallel to the center line, and on the center line, into the inside of the coil


110


. The limb


112


is used as a core for the coil configuration shown in

FIG. 5

, in conjunction with

FIGS. 6 and 7

.




It should also be mentioned that the dimensions of the configurations shown in drawings are not to scale.



Claims
  • 1. A magnetic release for an electrical switching device, comprising:a coil being stamped and bent from sheet metal composed of a material being electrically highly conductive and magnetically highly permeable, said coil having first webs disposed at a given distance from one another in a first plane and second webs disposed at the given distance from one another in a second plane and in each case run parallel to one another and offset with respect to one another, said coil having connecting webs in each case disposed between one end of one of said first webs and an adjacent end of one of said second webs and in each case one end of one of said second webs and an adjacent end of one of said first webs, said first webs, said second webs and said connecting webs disposed in such a manner that said first webs, said second webs and said connecting webs are in a helical shape around a center axis, said first webs, said second webs and said connecting webs defining an inside region in a form of a through-opening, said coil additionally having a stationary contact piece of a contact point for a circuit breaker; a holder for a thermal release integrally formed on said coil; a core accommodated in said through opening of said coil; and an armature selected from the group consisting of plunger-type armatures moving inside said coil and hinged armatures.
  • 2. The magnetic release according to claim 1, including:an arc guide rail integrally formed on said coil, adjacent to said stationary contact piece; and an arc splitter stack, for arc quenching, integrally formed on said arc guide rail, inside the electrical switching device.
  • 3. The magnetic release according to claim 1, including an L-shaped lug integrally formed at one end on said coil, said L-shaped lug having a free limb projecting into a coil area on its center axis, and forms said core.
  • 4. The magnetic release according to claim 1, wherein said first and second webs are U-shaped webs having limbs, and said U-shaped webs are open towards an opposite plane.
  • 5. The magnetic release according to claim 4, wherein each of said connecting webs are alternately connected at one end to one of said limbs of one of said U-shaped webs, and at another end to one of said limbs of another one of said U-shaped webs.
  • 6. The magnetic release according to claim 5, wherein said connecting webs each assume an angle to one another, and one of said connecting webs runs parallel to another, over others of said connecting webs.
  • 7. The magnetic release according to claim 1, wherein said connecting webs run parallel to one another at right angles to said center axis.
  • 8. A circuit breaker, comprising:a magnetic release including: a coil being stamped and bent from sheet metal composed of a material being electrically highly conductive and magnetically highly permeable, said coil having first webs disposed at a given distance from one another in a first plane and second webs disposed at the given distance from one another in a second plane and in each case run parallel to one another and offset with respect to one another, said coil having connecting webs in each case disposed between one end of one of said first webs and an adjacent end of one of said second webs and in each case one end of one of said second webs and an adjacent end of one of said first webs, said first webs, said second webs and said connecting webs disposed in such a manner that said first webs, said second webs and said connecting webs are in a helical shape around a center axis, said first webs, said second webs and said connecting webs defining an inside region in a form of a through-opening, said coil additionally having a stationary contact piece of a contact point for a circuit breaker; a holder for a thermal release integrally formed on said coil; a core accommodated in said through-opening of said coil; an armature selected from the group consisting of plunger-type armatures moving inside said coil and hinged armatures; and a housing having inner surfaces, mutually opposite ones of said inner surfaces having strips which engage between coil turns in order to guide said coil.
  • 9. The circuit breaker according to claim 8, wherein said strips are configured such that they are used to guide at least one of said core and said armature.
  • 10. The circuit breaker according to claim 8, including an arc guide rail integrally formed on said coil, said core, said stationary contact piece and said arc guide rail are disposed at one end of said coil, and said holder for the thermal release is disposed at another end of said coil.
Priority Claims (1)
Number Date Country Kind
199 09 111 Mar 1999 DE
CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of copending International Application No. PCT/EP00/01699, filed Feb. 29, 2000, which designated the United States.

US Referenced Citations (2)
Number Name Date Kind
5126715 Yerman et al. Jun 1992 A
5291173 Yerman et al. Mar 1994 A
Foreign Referenced Citations (7)
Number Date Country
1 764 087 Apr 1971 DE
31 43 210 May 1983 DE
148 789 Aug 2001 DE
0 439 389 Jul 1991 EP
2 586 135 Feb 1987 FR
2 721 431 Dec 1995 FR
04 196 507 Jul 1992 JP
Continuations (1)
Number Date Country
Parent PCT/EP00/01699 Feb 2000 US
Child 09/946942 US