US2270950A - Circuit breaker - Google Patents

Description

2 Sheets-Sheet l 1. G. JACKSON ET AL CIRCUIT BREAKER v original Filed sept. 3, 1935 Jan. 27, 19f2.

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Patented Jan. 27, 1942 s PATENT OFFICE clacurr aankan Jaim G. Jackson, Detroit, ma Wanne r. Auen,

Royal Oak. Mich., aaliguors to Square D Company, Detroit, Mieli., a corporation o! Michigan Application September 3, 1935, Serial No. 38,908 Renewed February 17, 1938 ssamm. (ci. zoo-11e) This invention relates to automatic electric circuit breakers and has for its object the provision of a simple and economical circuit breaker mechanism.

Another object of this invention is to provide an automatic electric circuit breaker which shall be tripped manually and automatically and in which the automatic trip shall be free ofthe operating member, the construction having a' minimum of parts.

Another object of this'invention is to provide an improved electrical circuit breaker apparatus embodying an outer sheet metal enclosure and at least one sealable circuit breaker within said enclosure, the circuit breaker mechanism having a simple, economical construction.

Another object ofthis invention is to provide an improved circuit breaker of multi-circuit form.

Another object of this invention is to provide an electrical circuit breaker having an im- -proved resetting and manually tripping mechanism. i v l Other objects and features of this invention will be readily apparent to those skilled in the art from the following speciilcation and the appended drawings illustrating certain preferred embodiments of the invention in which:

Figure l is a top plan view of the circuit breaker according to the present invention.

Figure 2 is a vertical sectional view taken on the line IIL-II of Figure 1.

Figure 3 is a sectional view taken on the line III-III of Figure2.

Figure-i is a fragmentary sectional view similar to Figure 2 showing the parts in the resetting position.

Figure 5 is a fragmentary sectional view similar to Figure 3 showing the manual tripping of the circuit breaker.

Referring to the drawings, the circuit breaker apparatus illustrated embodies an outer sheet metal box or cabinet I having an openable front cover 2. Within the box I is mounted at least one sealable circuit breaker 3. The circuit breaker specifically illustratedv comprises a base l having walls 5 extending therefrom at its edges and at a substantial mid portion. On either side of the middle wall 5 is mounted a resilient contact strip 6 rigidly secured to the base by means of .a stud 1 threaded into a connector 8. The connector 8 extends through the middle wall 5 and electrically connects the strips 6 on opposite sides oi this wall. This in iddle wall is, of course, not

ly or partially omitted as desired so long as minor clearances are preserved.

A resilient contact strip 9 is disposed generally parallel to each end of the strip I in spaced relation thereto. The strips l and the ends of strip I are biased in the same direction as shown in their separated position at the right of Figure 2. Cooperating contacts II and .t2 are rigidlysecured adjacent to the free ends of the strips l and 9 in any desired manner as, for instance, by brazing. The opposite ends of strips 9 are rigidly supported on the base l by means of studs I3.

A bixnetallic latching member I4 is rigidly secured to the base l by s tud I5 which stud further secures the terminal I9 extending to the exterior of the circuit breaker enclosure. 'Ihe latch Il is adapted to engage the end of contact strip 9 as shown at the left of Figure 2, thus restricting its forwardV movement and holding it in position for cooperation oi the contacts I I and' I2 underl the bias of the` strip 6. A flexible lead I1 electrically connects the free end of the bimetallic strip il with the fixed end of the contact strip 9. This lead may be welded or other wise attached to the bimetal .I4 and, as shown, is connected to the strip 9 through the lug 2l.

The resetting means for the circuit breaker comprises a push button I8 extending through the base 4. The inner end of ythe push button is reduced as at I9 and extends through an opening in the strip 9 where it is maintained by the pin 2|. The end of the strip 0 and the push button Il are thus connected together by means ot the abutment formed from the reduction of the portion I8 and the pin 2i. The portion 22 of the push button I8 immediately above the reduced portion I9 is flattened to receive the cam abutment 23 in non-rotatable relation. This caxn Vabutment assumes the shape more particularly shown in Figures 3 and 5, having a generally fiat surface disposed closely adjacent to the bimetallic latch Il. The portion 22 of the push button Il. extends through an enlarged opening in the strip 9 so as to be freely movable relative thereto. The upper portion of the stem of the push button I8 is provided with a limiting pin 24 adapted to cooperate with the under side of the base l to limit the outward movement of the push button and -with a projection 25 onthe base l to limit the f rotary motion thereof.

The circuit breaker mechanism is adapted to be I enclosed and for this purpose there is provided a nbre plate 20 of generally U-'shape having a cenessenti'al to the construction and may be entireas trally cutout portion in its legs adapted to engage the middle dividing wall 5 in the notches 21. For strengthening purposes, a sheet metal U-shaped member 28 is similarly disposed on the outside oi the bre plate 26. Tubular rivets 29 extend through the base I and rigidly connect the metal plate 2l and ilbre plate 26 to the base in scalable relation. The bolts 3| extend through the tubular rivets and engage with the back ot the box.or cabinet to mount the circuit breaker therein. 'I'he live studs 1, I3 and I5 are sealed as by means of wax Il.

The circuit breaker mechanism shown at the left ln Figure 2 is in the normal on" position with the strip 9 latched in position by the bimetallic member Il and the contact II is pressed against the contacty I2 by the resiliency of the strip l. The position of the parts in the tripped position is indicated at the right in Figure 2. Here the latch I4 no longer engages the end of strip t and this strip has moved upwardly under its bias to separate the contacts. The end of strip l is then i'ree to move also but is restricted due to its engagement with the abutment deilning the boundary between the portions I. and 22 on the push button Il and the engagement oi' the pin 2| on the push button with the under side of the base l. assuming the separated position shown. Itis noted from a comparison oi' the breaker mechanisms in Figure 2 that the push button has a further movement in its tripped position due to the fact that in the normal o position the pin 2l does not engage the base. This results in a desired indication oi the tripped position of, the breaker and a ring 32 or other means may be placed on the push button to more clearly indicate its outward position. This outward movement oi the push button is under the influence lof both resilient strips l and.) as strip l engages abutment 23 to aid in the outward movement.

Figure 4 shows the resetting position of thecircult breaker mechanism. The push button Il is pressed inwardly whereuponstrips 6 and 0 are moved away from the base I by the abutment 23 and the lower abutment between the portions Il and 22. It is noted that these two abutments y are spaced apart a distance greater than the normal spacing between the strips when the ccntacts are engaged, this resulting in the contacts being held separated while the push button is depressed. Release of the push button from the position shown in Figure 4 will permit strip i to move upwardly und] it engages latch Il, thus holding it in position. while the strip i will be tree to move upwardly with the push button to the position shown at the left in Figure 2 with the contact II pressed against the contact I2 by the resilient bias of the strip l.

The manual tripping oi' the circuit breaker is illustrated at the top of Figure 5. Upon rotation of the push button Il the cam abutment 2l engases the bimetallic latch I4 and moves it out oi engaging position with the strip D whereupon the parte are free to move to the separated positionshownattherightinFlgureZ. Thepush button Il is then automatically rotated back to its normal position by the reaction of the bimetal Il upon the cam abutment 2l. In the manual tripping movement the pin 2l and stop 2i limit the amount of rotation to prevent damage to The multi-circuit circuit breaker specifically i1- lustratedhasfourindividual circuit breaker mechanisma'one contact of each mechanism through the strips 8 and connector 8. It can be readily understood that any number oi' breaker mechanisms may be used within the spirit of the invention as applicants invention resides not only in the single breaker mechanism but also in the circuit breaker apparatus including the multi-circuit arrangement of a, breaker. In the breaker as illustrated it is intended that one circuit breaker mechanism shall serve as a main or lead-in circuit breaker and that the other three circuit breaker mechanisms shall serve as branch circuit breakers. AThis results in two current responsive circuit breaker mechanisms being in series with any short circuit which may occur.

While the contact strip B has been shown as a single member biased upwardly at its opposite ends, it is obvious that this strip may be divided This results in the contacts into two parts electrically joined by the connection with the connector 8. Although the box or cabinet has been shown with a single multi-circuit circuit breaker therein, it is obvious that any number of individual breakers may be mounted within the box or cabinet if desired.

In the following claims the terms box and "cover are intended to be construed to mean cabinet and door respectively as well.

Whilezcertain preferred embodiments of the invention have been speciiically disclosed, it'is understood that the invention is not limited thereto as many variations will be readily appa-l rent to those skilled in the art and the invention is to be given its broadest possible interpretation within the terms-of the following claims.

What ls claimed is: v

1. In an electric circuit breaker, separable contacts, means biasing said contacts in the. same direction, one contact having a released position beyond the released position of the cooperating contact, a current responsive latch for said one contact holding it in a position to be engaged by the cooperating contact, and a manually operable member for releasing said latch to permit manual v separation of said contacts, said member moving l being made electrically common with the others 1g said one contact ini'o relatching position after release, and means on said member for maintaining said contacts separated during the relatching operation.`

2. In an electric circuit breaker, separable contoets, means biasing said contacts in the same direction, one contact having a released pcsiti beyond the released position of the cooperating contact, a current responsive latch for said one contact holding it in a position to be engaged by the cooperating contact, a manually operable plunger having abutments for moving both contacts, said abutments being spaced apart so as to maintain said contacts separated while they are being moved against their bias to latch said one contact, release of said plunger permitting said cooperating contact to move to engage said one contact, and a surface on said plunger adapted said plunger to provide for manual trip.

3. In an electric circuit breaker, separable contacts, means biasing said contacts in the same direction, one contact having a released position beyond the released position of the cooperating contact, a current responsive latch for said one contact holding it in a pomtion to be engagedby the cooperating contact, and a manually operable plunger having a longitudinal movement to reset said breaker mechanism after automatic trip and a rotary movement to eii'eet manual trip.

4. In an electric circuit breaker, separable contacts, means biasing said contacts in the same direction, one contact having a released position beyond the released position of the cooperating contact, a current responsive latch for said one contact .holding it in a position to be engaged by the cooperating contact, and a manually operable plunger having a longitudinal -manual movement to reset'said breaker mechanism after automatic trip and a rotary manual movement to release said latch and effect separation of said contacts.

5. In an electric circuit breaker, separable contacts, a bimetalllc current responsive-element for normally latching said contacts in engaged position, said element releasing said contacts in response to an overload, a plunger for resetting said contacts in latched position, said plunger having a cam surface engaging said element to release said contacts upon manual rotation thereof. v

6. In an electric circuit breaker, separable contacts, a bimetallic current responsive element for normally latching said contacts in engaged position, said element releasing said contacts in response to an overload, a push button for resetting said contacts in latched position, said push button having a cam surface engaging said element to release said contacts upon manual rotation thereof, said element rotating said push button back into normal position when the manual rotary.A force is released.

7. In an electric circuit breaker, separable contacts, a current responsive latch for maintaining said contacts in cooperatinglrelation, a resetting push button, said push button having a longitudinal movement to separate said contacts and move them into latching position, a' reverse longitudinal movement to' engage said contacts, and arotary movement to release said latch and manually trip said contacts.

8. In an electric circuit breaker, contact arms biased inthe same direction, a. current responsive latch for the forward arm, cooperating contacts on said arms, a plunger connected to the rear arm, an abutment on said plunger for engaging the forward surface of said forward arm, said abutment and connection having a spacing greater than the engaged spacing of said arms, the forward movement of said plunger being restricted, whereby said contacts will remain separated when released by said latch.

9. An electric circuit breaker comprising a s ealable enclosure including a base. contact arms and means for limiting the forward movement of said plunger.

11. A multi-circuit circuit breaker comprising a scalable enclosure including a base, a plurality of electrically common contact arms supportedl by said base and biased in one direction, a plurality of electrically separate contact arms supported by said base and biased in the same direction, said electrically common and electrically separate arms being arranged .in pairs, the arms in each pair being generally parallel and superposed in said direction, and a separate current responsive latch for the forward arm in each pair, the forward movement of the rear arm being less than the forward movement of the forward arm when released by said latch.

12. A multi-circuit circuit breaker comprising a sealable enclosure including a base, a plurality of electrically common contact arms supported by said base and biased in one direction, a plurality of electrically separate contact arms supported by said base and biased in the same direction,

said electrically common and electrically sepasupported by said base within said enclosure and biased in the same direction, cooperating contacts on said arms, a current responsive latch for the forward arm, the forward'movement of the rear. arm being less than the forward lmovement of the 'forward'arm when said arms are released by said latch, and resetting means for said arms projecting through said enclosure, `said resetting means having a longitudinal movement -to engage said forward arm with said latch and a rotary movement to disengage said latch from said forward arm to provide formanual trip. Y

10. An electric circuit breaker comprising an enclosure including a base. resilient contact arms supported by said base within the enclosure and biased in the same direction, cooperating contacts on said arms, a current responsive latchy for the forward arm, a plunger loosely engaging the forward arm and connected to the rearward arm, an abutment on said plunger limiting the movement of the'forward arm relative thereto,

rate arms being arranged in pairs, vthe arms in each pair being generally parallel and superposed in said direction, a separate current responsive latch for the forward arm in each pair, a resetting push button positively engaging the rear arm and having an abutment for engaging said forward arm, and'xneans for limiting the forward movement of said push button.

13. A multi-circuit circuit breaker comprising a scalable enclosure including a base, a plurality of electrically common contact arms supported by said base and biased in one direction, a plurality of electrically separate contact armssupported by said base and biased in the same direction, said electrically common and electrically separate arms being arranged in pairs, the arms in each pair being generally parallel and superposed in saiddirection, a `separate current responsive latch for the forward arm in each pair, .a resetting push button positively engaging the rear arm and having an abutment for engaging said forward arm, means for limiting the forward movement of said push button, and a surface on said push button adapted to be rotated against said latch to provide for manual separation of said contacts.

14. In a multi-circuit circuit'breaker, a base, a resilient, substantially bow-shaped contact strip Vsupported on said base adjacent to a midportion, contacts mounted on said strip adjacent to the ends thereof, electrically separate contact strips supported by said base and extending generally parallel to the end portions of said first mentioned strip, said separate strips carrying contacts adjacent to their ends cooperating with the contacts on said first mentioned strip, said strips being biased in the same direction, and

current responsive latches engaging the forward strip ends to maintain said contacts in cooperating position. V 15. Amulti-circuit circuit breaker comprising [an enclosure including a base', a main circuit ,breaker and atleast one branch circuit breaker mounted on said base within said enclosure, each of said main and branch breakers comprising contacts biased in the same direction, a current responsive latch for the forwardcontact and means for limiting the released movement of the rear contact, the load contact of the main breakenclosure including a base, a plurality of pairs of cooperating contacts supported by saidbase within said enclosure, said contacts being biased in the same direction, a current responsive latch normally retaining the forward contact of each pair in position to be engaged by its cooperating contact, and a manually operable member for resetting each pair of contacts after an automatic release.

17. An electric circuit breaker comprising an enclosure including a base, a plurality of pairs of cooperating contacts supported by said base within said enclosure, said contacts being biased in the same direction, a current responsive latch normally retaining the forward contact of each pair in position to be engaged by its cooperating contact, and a. manually operable member for resetting each pair of contacts after an automatic release, said member being rotatable to engage said latch and manually release the respective cooperating contacts.

i8. An electric circuit breaker comprising an enclosure includinga base, a plurality of pairs of superposed contact arms supported by said base within said enclosure. said arms being biased in the same direction, cooperating contacts on each pair of arms, one arm of each pair being at least electrically common with one arm of each of the other pairs, a current responsive latch for the forward arm in each pair, and a manually operable member for resetting each pair of contacts from the released to the engaged position.

i9. An electric circuit breaker comprising an enclosure including a tusse, a plurality of pairs of superposed contact arms supported by said base within said enclosure, said arms being biased in the same direction, cooperating contacts on each pair of arms, one arm of each pair being at least electrically common with one arm of each of. the other pairs, a current responsive latch for the forward arm in each pair, and a manually operable member for resetting each pair of contacts from the released to the engaged position, said member having spaced abutments engaging said arms and maintaining the cooperating contacts separated until said member is released after reset.

20. An electric circuit breaker comprising an enclosure including a base, a plurality of pairs of superposed contact arms supported by said base within said enclosure, said arms being biased in the same direction, cooperating contacts on each pair of arms, one arm of each pair being at least electrically common with one arm of each of the other pairs. a current responsive latch for the forward arm in each pair, and a manually operable member for resetting each pair of contacts from the released to the engaged position, said member carrying a cam surface adapted to be rotated into engagement with said latch to effect manual release of the respective cooperating contacts.

3l. In an automatic electric circuit breaker, contact arms biased in tn e same direction, cooperating contacts on said arms, a bimetalllc latchlng member having relatively fixed and free ends with its free end normally holding the forward arm in position where the contacts will engage, said member iiexing under a current overload to release said forward arm, the released position of the forward arm being beyond the rebil leased position of the cooperating arm to effect for relatching said forward arm with said member after release including means for maintaining said contacts separated during the relatching operation.

22. In an automatic electric circuit breaker,

tion of the forward strip being beyond the released position of the cooperating strip to effect separation of said contacts, current responsive latching means normally retaining said forward strip in position where said contacts will engage, an operating plunger, a clearance opening in said forward strip through which said plunger extends, an abutment on said plunger engaging said forward strip, and a part on said plunger engaging said cooperating strip, the distance between said abutment and part being greater than the distance between said strips when the contacts are engaged, whereby the contacts will be separated when the plunger is depressed. 23. In a multi-circuit electric circuit breaker, a base, a plurality of pairs of cooperating contacts supported by said base. said contacts being biased in the same direction and one contact in each pair being electrically common with one contact in each of the other pairs, and a current responsive latch for the forward contact in each pair for normally retaining it in position to be engaged by its cooperating contact.

24. In a multi-circuit electric circuit breaker,

a base, a plurality of pairs of cooperating contacts supported by said base, said contacts being biased in the same direction and one contact in each pair being electrically common with one tacts supported by said base, said contacts being biased in the same direction and one contact inI each pair being electrically common with one contact in each of the other pairs, and a current responsive latch for the forward contact in each pair for normally retaining it in position to be engaged by its cooperating contact, the forward positions of said forward contacts when released by their latches being beyond the forward limit of movement of their cooperating contacts, and a manually operable member for resetting each pair of contacts after such release including means for maintaining the cooperating contacts separated during the resetting operation.

26. A circuit breaker comprising cooperating contact members biased to non-contacting positions,l one of said members including a slot. thermally-responsive locking means holding said members in .contacting relation, said means being adapted to release said members from said locked position at a predetermined temperature, and an operating member for resetting said Vcontact members to contacting relation including a handle, a heel for positively moving said slotted member, and a second heel adapted to extend through said slot to positively engage and move said other member, whereby said contact members cannot be normally held in contactinz Position by said handle.

27. A circuit breaker comprising a base. a movable terminal member mounted on the base, a movable contact member having a slot therethrough mounted on the base, said members being biased to non-engaging positions, thermallyresponsive locking means for holding said meinbers in positions for engaging relation adapted to release the same at a predetermined temperature, and a trip-free operating member ,for resetting said members to engaging position after a release, said operating member including means adapted to pass through the slot of the contact member ,to engage the terminal member, and means adapted to engage the contact member after the rst means has passed through and cleared the same, whereby the ter-v minal member will be positively maintained out of engagement with the contact member during resetting of the contact member.

28. In an automatic electric circuit breaker, cooperating contacts, means biasing said contacts in the same direction, one of said contacts having a released position beyond the released position of the cooperating contact, current responsive latching means for said one contact holding it in position to be engaged by the cooperating contact, and manual means for resetting said contacts after release by said latch,

said contacts being maintained separated during the resetting operation, said manual means being manipulable to eiiect manual separation oi the contacts at will. said manual separation being maintained when the manual means is released. v

29. In an automatic electric circuit breaker. cooperating contacts, means biasing said contacts in the same direction. one of said contacts having a released position Vbeyond the released position oi the cooperating contact, current responsive latching-means for said one contact holding it in position to be engaged by the cooperating contact,vsaid means including a current traversed, bimetallic element adapted to iiex upon the passage oi an overload current therethrough, and manual means for resetting said contacts after release by said latch, said contacts being maintained separated during the resetting operation, said manual means being macondition of manual separation after nipulable to eilect manual separation of the contacts at will, said manual separation being maintained when the manual means is released.

30. In an automaticelectric circuit breaker, cooperating contacts, means biasing saidv contacts in the same direction, one of said contacts having a released positionV beyond the released position o! the cooperating contact, current responsive latching means for said one contact holding it in position to be engaged by the cooperating contact, and operating means having a manually manipulable portion at the exterior oi the circuit breaker enclosure, said operating means being manually manipulable both to reset said contacts in latched position after a release and to manually, separate said contacts, said oontacts being maintained separated during the resetting operation and having a stable, separated being manipulated thereto. I

3l. A thermally operated current responsive switch of the class described, comprising, in combination, a support, a nrst spring contact blade having one of its ends fixedly 'secured thereto, a second spring contact blade also having one of its ends fixedly secured to said support near the fixed end of said ilrst spring contact blade and extending substantially parallel to said ilrst blade, said spring contact blades being normally biased to open circuit position, locking means to hold said contact blades in closed circuit posltion including a thermally responsive means which if removed renders said locking means ineiective to hold said contact blade in closed circuit position, said locking means being adapted to release said contact bades for movement to open circuit position at a predetermined temperature, and manual means for moving said contact blades to locking position after they have been released, said manual means maintaining said contact blades in open circuit relation during the locking operation, said manual means being also manipulable to-eiiect a stable separation of the contacts at will with the manual separation maintained when the means is released.

32. A thermally operated current responsive switch of the class described comprising a pair of electrical contact .carrying blades each anchored at one end and biased awayfrom each other to normally open the contacts, a bimetal' strip thermal element and means for operatively yassociating the thermal bimetal strip element with the contacts to normally afford endwise resistance by the bimetal strip to opening movement of the contacts, warping movement of the bimetal strip under iniluence oi heat shifting the end oi said bimetal strip to permit'the con.- tacts to open under their normal bias, the parts being so arranged that upon removal or breakage oi' the bimetal strip the contacts will separate, and means for resetting said contacts to closed position comprising a movable member separately moving eachof said contact blades to retain them separated until the thermal bimetal strip has been endwlse engaged to. retain one of said con- -tact blades in its reset position before the other released.`

JOHN G. JACKSON.

' WAILACI T. ALBIN.

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