US2020334A - Automatic circuit breaker - Google Patents

Description

ttar'ngy .LsAcHs AUTOMATIC Nov. 12, 1935.

CIRCUIT BREAKER 2 Sheets-Sheet l Filed Oct. 14, 1955 assi/U .5y Jl. 2,

Nov. 12, E935. J, SACHS 2,020,334

AUTOMATI C CIRCUIT BREAKER Filed Oct. 14, 1935 2 Sheets-Sheet 2 Jhr/ent ar :JasL/Uh .Sachs Patented Nov. 12, 1935y UNITED STATES PATENT OFFICE Claims.

This invention relates particularly to an automatic circuit breaker of the type set forth in my patent for Automatic circuit breakers, No. 1,592,632 dated March 27, 1934 and in my application for Automatic circuit breaker, Serial No. 693,081 iiled October 11, 1933.

In my said patent I have disclosed a circuit breaker which includes a movable contact member provided with a movable contact adapted to engage and disengage a stationary contact and which also includes a movable actuating member or actuator normally serving to effect the movement of the contact member to bring the movable contact into or out of engagement with the stationary contact. An electro-responsively controlled mechanical connection is provided between the .actuator and the contact member, and this connection is automatically released upon the attainment of excess current conditions in the circuit, thus permitting the contact member to automatically move to open-circuit position. In accordance with the invention disclosed in the said patent, a movable operating member is provided in association with the actuator, and interposed between the said operating member and the actuator is a means such as an over-the-center spring for efiecting movement of the actuator and of the contact member with a snap action independent of and uncontrolled by the movement of the operating member.

The general object of the present invention is to provide an automatic circuit breaker of the general type disclosed in my said patent but having certain advantageous details of construction and operation. A more specific object of the invention is to provide a circuit breaker having the quick-make-and-break features disclosed in the said patent and having an arrangement of contacts and other parts similar to that disclosed in my said application Serial No. 693,081.

Further and more specific objects of the in- .vention will be apparent from the following specbodying the invention.

Fig. 2 is a view similar to Fig. 1, but showing the front insulating cover removed.

Fig. 3 is a fragmentary sectional view taken along the line 3-3 of Fig. 1.

Fig. 4 is a longitudinal sectional view taken along the line 4-4 of Fig. 2 and showing the movable parts in their closed-circuit positions. 5

Fig. 5 is a transverse sectional view taken along the line 5--5 of Fig. 4, but omitting the front cover.

Fig. 6 is a longitudinal sectional view taken along the line 6 6 of Fig. 2 and showing the 10 movable parts in their open-circuit positions.

Fig. 7 is a fragmentary view similar to Fig. 6, but showing the movable parts in different relative positions.

Fig. 8 is a detail perspective view showing 15 certain parts of the circuit breaker separated from each other.

In the drawings I have shown a circuit breaker embodying the invention, this circuit breaker being `particularly adapted for panel board use. There is provided a main insulating base or support 2| which carries all of the other parts of the circuit breaker. Fitting the support 2| at the front thereofl is an insulating cover 22. The rear support 2| is of box-like form, being substantially 25 closed at all four sides and at the bottom. The front cover is also of more or less box-like form,`

'having a recess open at the bottom into which certain parts of the mechanism project. When the two parts 2| and 22 are assembled as shown, there is provided an interior recess which contains all of the operative Aparts of the circuit breaker other than the handle. The two parts may be connected by suitable screws or bushings extending through holes at 22a, 223.

Carried by the rear support 2| near the front thereof are two forward projecting parallel metallic plates 23, 23 which are held in place by means of screws 24, 2l extendingforward from the rear of the support. The two plates 23, 23 40 are preferably integral with each other, being connected by a transverse flange 23H. The plates 23, 23 are provided with integral rearward extending portions 23", 23h, and on these rearward extensions are inward extending pivot studs 25, 25. A pivotally Amounted contact carrying member is providedwhich includes two parallel plates 26, 26 spaced apart transversely and pivotally mounted on the respective studs 25, 25. Suitable spacing washers hold the plates in proper spaced relationship to the supporting plate extensions 23h, 23.

The two plates 26, 26 serve to carry the main movable contacts 21 and 28 of the circuit breaker, and while I do not necessarily so limit myself, 55

l' prefer to construct and arrange the contacts in a manner set forth in my said copending application, Serial No. 693,081. The two contacts are positioned between the outer planes and the two plates 26, 26 and they are arranged in tandem, that is, they are spaced apart in the direction oi movement or circumferentially. Preferably and as will be clearly apparent from an examination of Figs. 5 and 8, each movable contact 2l and 28 extends from one to the other of the two plates 26, and is in direct engagement with both oi them. Preferably and as shown each oi the said plates 26 is provided with a hole 2@ and a notch adapted to receive similarly shaped lateral projections on the correponding contact. "When the said projections on the contacts are ent ed in the said holes and notches ci the two pistes, the contacts are firmly held in proper predetermined relationship. It will be observed that, by reason of the tandem arrangement of the contacts, the two plates 2i,

are much closer together than would otherwise be possible. The reduction in the distance between the plates makes it possible for the entire circuit breaker to be correspondingly narrower.

The two plates 28, 26 are additionally connected and held in spaced relation by means of insulating members il and 32. The said members Si and 32 are preferably structurally separate from the plates, and as shown the plates are notched at 33, 34, 35 and 3S to receive projections 38, Se and 3S formed on the insulating members. The two plates and the insulating members are held in proper relationship by means oi `tie rods or rivets 4i, 4| extending through suitable holes 42, 42 and 43, 43. Preferably the plates 25, 25 have arcuate outer edges concentric with the pivotal axis at 25, 25 and the insulating members 3i and 32 are externally shaped to conform to these arcuate edges.

The two movable contacts 21 and 2B are electrically connected with each other, this electrical connection preferably being through an electroresponsive means which is carried by and is bodily movable with the contact member. By preference and as shown, this electro-responsive means is a loi-metallic thermostatic strip 44 mechanically and electrically connected directly with one oi the contacts, as for instance the contact 28. The strip 44 is provided at its projecting end with a lug 45 which enables the strip to serve as a latch as will be presently explained.

In order to complete the electrical connection between the two contacts 21 and 28 there is provided a suitable flexible connection 46 between the strip 44 and the contact 21. This flexible connection may be widely varied as to details, but as shown it consists ci a stranded or braided flat strip, The strip 46 is surlciently flexible to permit the loi-metallic strip 44 to freely deflect or bend under the influence of heat.

Carried by the insulating support 2| are two substantially stationary main contacts 41 and 48 which are connected with the said support by means o more or less resilient bent conducting straps 49 and 50. These stationary contacts 41 and 48 are so positioned and arranged that they can be firmly engaged respectively by the two movable contacts 21 and 28 as clearly shown in Fig. '4. The outer end of the supporting strap 49 is held in place by means of screws 5| and it is connected by means of a screw 5| with a rearward extending conductor 52. A recess 53 in the cover 22 provides access to the screw 5h. The outer end of the conducting strap 50 engages the bottom wall of a recess 54 formed in the main support 2| and is held in place by screws 55. The conductor 50 has a laterally extending portion 56 which is provided with a wire terminal 56a. Suitable recesses 51 are formed in the upper left hand corners oi the support 2| and oi the cover 22 to permit access to the said Wire terminal 56a.

It will be apparent that pivotal movement of the contact member serves to bring the movable contacts 21 and 28 into or out of engagement with the respective stationary contacts 41 and 48 to make or break the circuit. When the parts are in the contact engaging position as shown in Fig. 4 electrical connection is established between the conductor 52 and the terminal 56B. A suitable spring 58 is provided for biasing the member in the Contact disengaging or circuitopening direction. This spring surrounds one of the pivot studs and is between the supporting plate extension 23b and the insulating plate 26.

For actuating the contact member for normal switching purposes or to eiect closing of the circuit after automatic opening thereof, I provide a member which I shall term an actuating member or actuator. The actuator is shown as being mounted co-axially with the Contact member, but as to this coaxial mounting I do not necessarily limit myself. Preferably and as illustrated the actuator consists of two spaced metallic plates 59, 59 mounted on the pivot studs 25, 25 between the plates 2S, 26, the said actuator plates 59, 59 being held in place by means of integral heads on the said studs. At their lower or inner ends the actuator is provided with a transverse pin or roller 40 which, at normal ternperatures, is engaged by the lug 45 on the thermostatic latch 44. With the parts in the relative positions shown in Fig. 4 the actuator and the contact member are positively connected to move in unison. Preferably in order to limit the pivotal movement of the actuator the said plates 59, 59 are provided with outwardly bent ears 59a, 59 which extend through slots 60 formed in the respective plates 23, 23.

A manually accessible operating handle is provided, this being mounted for sliding or rectilinear movement. Preferably and as shown the handle member 6| is constructed and shaped to slide along a flange 23a on the supporting plates 23, 23. The handle member has a ilat inner portion which engages the flange and has another portion which extends outward through a slot 62 in the cover 22 so as to be adapted to be conveniently engaged manually. The at portion of the handle member is long enough to entirely close the slotl 62 with the handle member in any position. Carried by the handle member is a metal plate 63 which extends downward through a slot 23c in the flange 23, and this plate $3 is connected with the actuator 59 by means of a tension coil spring 64. The spring 64 directly engages the said plate 63 and it is connected with the actuator 59 indirectly through the medium of a U-shaped yoke 65 which is connected with the plates 59, 59 by means of the pin 40.

When the parts are in the relative positions shown in Fig. 4 the spring 64 holds the actuator and the contact members in their extreme right hand positions, thus holding the movable contacts 21 and 28 in rm engagement with the stationary contacts 41 and 48. When the handle member il is moved toward the left the spring 64 moves between the legs of the actuator until it passes the dead center position and then the spring serves to move the parts quickly and with a snap action to the open-circuit position shown in Fig. 6. In this position the plates 26, 26 ofv the contact member engage stops 234, 234 on the supporting plates 23, 23. When the handle is moved back to the closed-circuit position yshown in Fig. 4 the operation is reversed and the contacts are moved quickly to the closed-circuit positions with a snap action.

As already explained the bi-metallic strip 44 is electrically connected between the movable contacts 21 and 28. It is adapted to be deflected downward or outward upon the passage of excess current therethrough, with the result that the lug 45 is disengaged from the pin or roller I0. Upon such disengagement the contact member with the contacts 21 and 28 thereon is moved by the spring 50 to the full open-circuit position as shown in Fig. 7. It will be understood that in order to close the circuit after the contact member'has automatically moved to the position shown in Fig..7, it is necessary to first move the handle member 6| to the open-circuit position so as to permit the lug 45 to reengage the pin or roller 40. After that the circuit can be closed in the usual way as already described.

I have only brieily described the supporting and enclosing members 2| and 22 as these may be widely varied. As shown they are particularly adapted for panel board use. In order to accommodate the bus bar A of a panel board, the rear supporting member 2| is provided with a transverse notch or recess 66. The before-mentioned conductor 52 may be connected directly with the bus bar by means of a screw 52".

I have referred to a recess `54 in which are located portions of the conductor 50. In order that this recess may^normally be substantially closed I preferably provide a separate insulating block 61 adapted to fit this recess. Preferably the sides of the recess Il are provided with grooves and the block 61 is provided with tongues 68, 68 adapted to enter the said grooves and thus hold the block in place.

i For controlling and confining the arc-formed gases I provide means similar to those disclosed in my said copending application, Serial No. 693,- 081. The path of movement of each movable contact is surrounded by four insulating walls, three of the walls being stationary and one of the walls being movable. For the contact 21 the movable wall is the outer surface 89 of the insulating member 32 and for the contact 2l the movable wall is the outer surface 10 of the insulating member 3|. The main support 2| is formed with an arcuate wall 1| concentric with the said wall B9 and the auxiliary block 61 is formed with a wall 12 concentric with the wall 10. Discharge vents 12 extend downward from the surface 1| and communicate with a duct 14. which duct is closed at the rear by means of a separate insulating plate 15 held by screws 16. The duct 14 communicates with a duct 11 which terminates in a discharge opening at the left hand end of the circuit breaker and in the recess i1. Formed in the block 61 are vents 1I, 1I which communicate with a duct 19 in the block, this duct in turn communicating with an open notch 80 in the cover 22. It will be apparent that, by

, means of the vents 13, 13 and 1I, 1l and the described ducts, the arc-formed gases can be discharged, the construction being such that the gases are cooled prior to discharge.

When two or more circuit breakers are to be placed closely adjacent each other, as in a panel board, each two adjacent circuit breakers may be held by a single screw as indicated in Figs. 1 and 3. As shown the main insulating members 2| and 22 are provided at opposite sides with semi-cylindrical grooves 19, 19, a recess 80 being formed at the top of each groove. When two units are placed side by side the grooves and recesses of the adjacent parts register with 10 each other and the two registering grooves 19 are adapted to receive a screw such as 8|. The head of the screw engages a lock plate 82 having its edges bent rearward to enter notches in the recesses NI, 80. Thus each screw 8| serves to 15 hold thc two adjacent circuit breaker units.

What I claim is:

1. The combination in an automatic circuit breaker, of a main insulating support, a structurally separate insulating cover on the support, 20 a rectilinearly movable operating member supported and guided on the main support independently of the cover but having a portion accessible through an opening in the cover, a pivoted actuator on the support, a pivoted contact 25 member on the support biased independently of the actuator toward. its open-circuit position and releasably connectible with the actuator so as to be normally controlled thereby, a mechanism operatively interposed between the operating mem- 30 ber and the actuator and serving upon movement of the former to effect movement of the latter and of the contact member, the said mechanism including a spring for effecting such movement with an independent snap action, and an electro-re- 35 sponsive means serving upon the attainment of abnormal current conditions in the circuit to release the contact member from the actuator for independent automatic circuit-opening movement.

2. The combination in an automatic circuit breaker, of a main insulating support, two spaced supporting plates on the support, a rectilinearly movable operating member supported and guided on the supporting plates, a pivoted actuator on s the support, a pivoted contact member on the support biased independently of the actuator toward its open-circuit position and releasably connectible with the actuator so as to be normally controlled thereby. a mechanism operatively in- 50 terposed between the operating member and the actuator and serving upon movement of the former to eifect movement of the latter and of the contact member, the said mechanism including a spring for eiecting such movement with an 55 independent snap action, and an electro-responsive means serving upon the attainment of abnormal current conditions in the circuit to release the contact member from the actuator for independent automatic circuit-opening movement. o0

3. In an automatic circuit breaker, the combination of two spaced supporting plates. a U- shaped actuator pivotally mounted between the supporting plates, a contact member including two spaced side plates at opposite sides of the g5 actuator and also pivotally mounted between the supporting plates, the said contact member being biased for circuit-opening movement independently of the actuator, an electro-responsively controlled mechanical connection between the actuator and the contact member normally enabling the former to move the latter to open and close the circuit, the said mechanical connection being automatically releasable upon the attainment ofv abnormal current conditions to per- 4. In an automatic circuit breaker, the com` bination of two spaced supporting plates, a contact member pivotally mounted between the supporting plates and including two spaced side plates and also including two electric contacts arranged in tandem between the outertplanes of the side plates, two stationary contacts engageable by the movable contacts, means for b'asing the said contact member for independent circuit-opening movement, a U-shaped-actuator pivotally mounted between the side plates of the contact member, an electro-responsively controlled mechanical connection between the actuator and the contact member normally enabling the former to move the latter ton open and close the circuit, the said mechanical con'- nection being automatically releasable upon the attainment of abnormal current conditions to permit automatic circuit-opening movement of the contact member, a movable operating member, and an over-the-center spring between the two legs of the actuator and serving as an operative connection between the operating member and the actuator for effecting snap opening and closing movement of the actuator and the contact member.

5. In an automatic circuit breaker, the combination of two spaced supporting plates, a U- shaped actuator pivotally mounted between the supporting plates, a contact member including two spaced side Vplates at opposite sides oi' the actuator and also pivotally mounted between the supporting plates, the said contact member being biased for circuit-opening movement independently of the actuator, an electrorespon sivelycontrolled mechanical connection between the actuator and the contact member normally enabling the former to move the latter to open and close the'circuit, the said mechanical connection being automatically releasable upon the attainment of abnormal current conditions to permit automatic circuit-opening movement of the contact member, a rectilineaily movable operating membercarried by the supporting plates, and an over-tne-center spring between the two legs of the actuator and serving as an operative connect'on between the operating member and.

the actuator for effecting snap opening and closing movements of the actuator and the contact member.

JOSEPH SACHS.

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