US2685011A - Electric circuit breaker - Google Patents

Description

July 27, 1954 w BOLLER ET AL 2,685,011

ELECTRIC CIRCUIT BREAKER Original Filed June 10, 1948 ATTORNEYS Patented July 27, 1954 ELECTRIC CIRCUIT BREAKER William D. Boiler, Milford, Ohio, Warren D. Berkley, Fort Wayne, Ohio, and Edwin Ind., Walter Ernst, Dayton, W. Landmeier, Covington,

Ky., assignors to The Wadsworth Electric Mfg. 00., Covington, Ky., a corporation of Kentucky Original application 32,204, now Patent 4 Claims. 1

This invention relates to circuit breakers, and is concerned primarily with a circuit breaker intended to control the circuits in homes and comparable places.

This application is a division of our United States patent application Serial No. 32,204, which was filed June 10, 1948, for Electric Circuit Breaker, and which is now issued as United States Patent No. 2,618,716, dated November '18, 1952.

At the present time, the electrical installations for homes, business establishments, and other places making use of the current supply that is made available by the electric companies includes one or more circuits, each of which embraces a fuse and sometimes a switch associated therewith. When the circuit is overloaded or a short circuit develops, the fuse burns out in a well-known manner and must be replaced before service can be restored.

The present invention has in view as its foremost objective the provision of a circuit breaker which is intended to replace the fuse and switch heretofore employed in controlling such circuits.

Under practical conditions, a plurality of circuits are ordinarily included in electrical installations of the type with which this invention is concerned and a further object of the invention is the provision of a circuit breaker which is susceptible of being assembled in multiple or gangs with each unit controlling one circuit.

In the known combination units of the type intended to be improved by this invention, it has been the practice to provide a pair of contacts for controlling the circuit. When these contacts are in engagement, the circuit is closed and when they are spaced apart, the circuit is open. Usually one of these contacts is fixed and the other is movable. The present invention has in View as an important object the provision of a circuit breaker of the type indicated in which both of the contacts are movable. This arrangement presents certain definite advantages. It is possible to provide for the movement of one contact into opened or closed position under the influence of a manually operable lever while the other contact is placed under the control of the circuit conditions so as to be moved into opened position under overload or short circuiting conditions. This latter contact may No. her 18, 1952. Divided a ruary 16, 1952, Serial June 10, 1948, Serial No.

2,618,716, dated Novemnd this application Feb- 2 be moved back into circuit closing position under the influence of the manually operable lever.

To the end of keeping the contacting surfaces clean a further object of the invention is the provision of a circuit breaker of the type indicated in which the contacts are separated with a wiping action in contrast to a direct pull apart.

In circuit breakers of the type with which this invention is concerned, the opening of the contacts is placed under the control of a bimetallic thermostat together with a so-called rupture magnet that is affected by the current conditions to vary the strength thereof. The bimetallic thermostat is heated by overload conditions and when a predetermined condition is reached opens the contacts, whereas the rupture magnet is affected by a short circuit or other comparable instantaneous condition to immediately open the contacts. It has been the practice to mount the rupture magnet on the thermostat so that it is movable therewith. However, the present invention contemplates the mounting of the rupture magnet in a fixed position in the casing and an armature which cooperates therewith is carried by a latch which controls relative movement of the contacts. This arrangement presents certain advantages not only as to ease of assembly but also in sureness of operation. With this arrangement, the rupture magnet is mounted with no physical connection between it and the bimetallic thermostat.

Still another object of the invention is the provision, in a circuit breaker of the type aforesaid, of a novel assembly of a latch, keeper piece, and rivets which is highly simplified as compared to anything heretofore provided for this purpose.

Various other more detailed objects and advantages of the invention such as arise in carrying out the above noted ideas in a practical embodiment will in part become apparent and in part be hereinafter stated as the description of the invention proceeds.

For a full and more complete understanding of the invention reference may be had to the following description and accompanying drawings wherein:

Figure 1 is a longitudinal vertical section through a second modification with certain parts being shown in elevation and depicting the position of the contacts and associated elements after rupture by circuit conditions;

Figure 2 is a sectional view similar to Figure 1 of the same modification but developing the normally closed position;

Figure 3 is a top plan view of the circuit breaker shown in Figures 1 and 2.

This casing of the electric switch and circuit breaker is shown in the drawings and is identifled by the reference character H5. The casing has a top wall II6 which is formed with a large aperture at II1 which accommodates movement of a lever II8 which carries at its free end an operating member of insulating material such as shown at II9.

Substantially opposite to the opening M1 the bottom wall of the casing which is identified at I23 has an inwardly extending boss I2I formed with a recess I22. The ends of the lever I I8 are of a rounded nose construction and are received in this recess which functions as a pivot point for the lever II8.

The side wall of the casing is designated I23 and extending inwardly therefrom is a rib 2d formed with a downwardly exposed rounded notch I25 which receives the end of a contact carrier I26 that is of a complemental rounded shape. The contact carrier I23 pivots on its upper end which is received in the recess I25. A tension coil spring I21 has its upper end anchored to the lever I I3 as by the pin I28, while its lower end is anchored to the contact carrier I23 as by being received in a slot I29 therein. The spring I21 serves to bias the contact carrier on one side or the other of dead center as determined by the relation of the upper end of the contact carrier I26 with respect to the ends of the spring.

A contact I33 is employed on the lower end of the carrier I26 and a flexible electrical connector I3I connects the carrier with a terminal plate I32 which is anchored in the end wall of the casing. A leaf spring shown at I33 is anchored to the bottom wall I28 as indicated at I34 and functions as an over-travel spring which limits swinging movement of the lever II8. I35 is pivotally mounted between the side walls of the casing and cover as represented at I36. The lower end of this rocker carries a contact I31 which is adapted to come into abutting engagement with the contact I36 as shown in Figure 2.

Beneath the pivotal point I33 the rocker I35 is formed with a flange I36 that is represented by the dotted lines in Figures 1 and 2. An arm I39 outstands from the lever II8 and at its free end carries a flange MU which is adapted to engage the flange I33 when the rocker is in the ruptured position depicted in Figure l. The rocker I35 is also formed with a flange MI which is adapted to function as a stop in cooperation with a detent member to be later described.

Referring for the moment more particularly to Figure 3 which will be considered in conjunction with the upper part of Figures 1 and 2, it will be noted that the top wall I I6 is formed with an opening I42 which may be closed by a slide I44. Immediately adjacent this opening I52 the underface of the top wall H6 is recessed to accommodate slide I 34. Extending downwardly from the lower face of this slide is an ear hi5 which is connected by a link N56 with the upper end of the rocker I35 as indicated at I41. The slide I56 carries suitable indicia as shown in Figure 3 to indicate when the circuit breaker has been ruptured by a predetermined circuit condition and is to be reset.

A rocker At this point it is well to note that the top may also carry suitable indicia which cooperate with the operating member H9 to indicate the position to which the unit has been set.

A bimetallic thermostat is represented at I48 and the inner end of this thermostat is secured to an anchoring member I49 which is adjustable through the medium of the screw stem I53 that is appropriately mounted in the end wall of the casing.

A latch member I5I comprises a shank of spring construction as illustrated and at its free end carries a detent I52 which cooperates with the stop I4I to hold the rocker I35 against rotative movement when in the position of Figure 2, and a tension coil spring I53 has one end anchored to the rocker I35 below the pivot point I33 as shown at I54 and the other end is immovably secured as represented at I55 to a member which also mounts a magnet I56. The normal tendency of the spring I53 is to urge the rocker I35 in a counter-clockwise direction, speaking with reference to the showing in the drawings.

A coil I51 is wound about the face of the U- shaped magnet I56 and one end of this coil is connected by an electrical connector I58 with a terminal plate I59. The other end is connected by a flexible connector I60 with the thermostat Id8 adjacent to its anchorage. Still another fiexible connector I6I connects the free end of the thermostat and the rocker I35.

A stop for limiting swinging movement of the contact carrier I26 in a counter-clockwise direction is shown at I62. An armature for the magnet I56 is represented at I63 and is pivotally mounted at one end on the structure represented at I55, while at its other end is received in the opening defined by the U-shaped detent I52 of the latch I5I.

It will be noted that the construction shown in the drawings provides a pivotal mounting of the manual operating lever I It at the bottom of the casing. The tension spring I21, through which over center forces are applied to the contact carrier I26, is connected at its upper end to the operating lever II8 and at its lower end to the contact carrier I26. The construction provides substantial movement of the spring in response to lever movement, because of the substantial separation of the points of spring attachment with respect to the pivotal axis of the contact carrier, and thereby provides a pronounced snap action effect which is desirable for minimizing arcing when the contacts are disengaged. Also, the tensional force of the spring is borne entirely by the casing at the respective fulcrum notches I25 and I22 which are contained therein. Hence, the effects of wear of the parts are minimized.

Operation of the device Figure 2 depicts the position of the combination switch and circuit breaker when the circuit is closed. This is caused by the engagement of the contacts I30 and I31. It will be noted that the spring I21 being biased at one side of the pivot point I25 continuously urges the contact I33 against the contact I31.

If the switch is to be manually opened the lever II8 is swung to the off position as indicated in Figure 3. As this movement takes place the spring I21 passes dead center, whereupon it biases the contact carrier I26 to rotate the latter in a clockwise direction and move the contact I30 away from the contact I31. This rotative movement of the carrier I26 is limited by the stop at I54. When the switch is to be closed from this oiT position all that is necessary is to swing the operative member I i9 into the on position illustrated, which again causes the spring to pass dead center so that it biases the contact carrier H5 in a coimterclockwise direction and brings the contacts into engagement.

Upon the occurrence of a predetermined circuit condition such as a short circuit or an overload, either the armature IE3 or the bimetallic thermostat I38 will affect the latch I5i to move the detent I52 downwardly out of the path or the stop I 4|. The spring I53 will now be effective to move the rocker I35 in a counterclockwise direction and thus the contact I31 away from the contact I30. At the same time through the comiection provided by the linir M5 the slide I44 is moved to bring the word reset beneath the opening I42. This rupture interrupts the circuit and indicates by the slide that the unit will have to be reset to restore the completed circuit.

To accomplish the reset the operator moves the member I I9 into the reset position by forcing H8 against over-travel spring; I33. This causes a swinging of the lever H8 on the pivot I22. It will be noted from Figure 1 that in the ruptured position the flange M0 on the arm I39 is substantially in engagement with the flange I38. As this movement of the lever H8 takes place the rocker I35 is rotated in a clockwise direc tion to again bring the contact I3! into engagement with the contact I and at the same time moves the stop I lI into effective engagement 0 with the detent I52. It will be noted that when the rocker I is swung to the ruptured position any movement of the contact carrier I26 under the influence of the spring I2! is inhibited by the stop I52.

What is claimed is:

1. An electric circuit breaker comprising, a casing having a bottom wall containing a pivot notch, a manually operable lever having a bottom endwise portion pivotally mounted in said notch and having its opposite end extending through the top of said casing, a contact carrier pivotally mounted on said casing at a point between the top and bottom of said lever, and a tension spring extending above and below the pivotal axis of said contact carrier, one end of said spring being connected to said manually operable lever, and the other end to said contact carrier, the said elements being so positioned that the line of force exerted by said spring is shiftable from one side of the pivotal axis of said contact carrier to the other side thereof, for effecting snap action movement of said contact carrier, in response to actuation of said lever, a rocker member pivotally mounted in said casing, the said contact carrier and rocker member having cooperable contacts thereon, means normally restraining the said rocker member against pivotal movement, and means including a latch responsive to circuit overload conditions for effecting operation of said rocker member into contact disengagement position independently of movement of said operating lever.

2. An electric circuit breaker comprising, a casing having a bottom wall containing a pivot notch, a manually operable lever having a bot tom endwise portion pivotally mounted in said notch and having its opposite end extending through the top of said casing, a contact carrier pivotally mounted on said casing at a point between the top and bottom of said lever, and

a tension spring extending above and below the pivotal axis of said contact carrier, one end of said spring being connected to said manually operable lever, and the other end to said contact carrier, the said elements being so positioned that the line of force exerted by said spring is shiftable from one side of the pivotal axis of said contact carrier to the other side thereof, for effecting snap action movement of said contact carrier, in response to actuation of said lever, a rocker member pivotally mounted in said casing, the said contact carrier and rocker member having cooperable contacts thereon, means normally restraining the said rocker member against pivotal movement, and means including a latch responsive to circuit overload conditions for efiecting operation of said rocker member into contact disengagement position independently of movement of said operating lever, the said casing having a stop member which is engageable by the said contact carrier when the same is in contact engaging position, the said stop member residing closely adjacent the contact on said contact carrier and acting thereby as an arc shield.

3. An electric circuit breaker comprising, a casing having a bottom wall containing a pivot notch, a manually operable lever having a bottom endwise portion pivotally mounted in said notch and having its opposite end extending through the top of said casing, a contact carrier pivotally mounted on said casing at a point between the top and bottom of said lever, and a tension spring extending above and below the pivotal axis of said contact carrier, one end of said spring being connected to said manually operable lever, and the other end to said contact carrier, the said elements being so positioned that the line of force exerted by said spring is shiftable from one side of the pivotal axis of said contact carrier to the other side thereof, for efiecting snap action movement of said contact carrier, in response to actuation of said lever, a rocker member pivotally mounted in said casing, the said contact carrier and rocker member having cooperable contacts thereon, means normally restraining the said rocker member against pivotal movement, and means including a latch responsive to circuit overload conditions for efiecting operation of said rocker member into contact disengagement position independently of movement of said operating lever, the said casing having a yieldable member mounted therein which is engageable by said contact carrie in its movement away from contact disengagement, whereby the said yieldable member resiliently brings the contact carrier to rest, against the influence of said tension spring, following operation of said lever for effecting contact disengagement.

4. An electric circuit breaker comprising, a casing having a pivot notch formed in a bottom wall thereof and having a slot in the top wall thereof, an operating lever having one endwise portion pivotally journalled in said notch and having the opposite endwise portion extending through said slot and carrying a handle therebeyond, the said casing having a portion providing a second pivot notch extending from a side wall portion thereof at a point intermediate the top and bottom of said casing, a contact carrier having an endwise portion thereof journalled in said second notch and extending in a direction toward said first notch, and a tension spring interconnecting an endwise portion of said contact carrier which is spaced from the second notch to said lever at a portion thereof which is spaced from the first notch and which is at the opposite side of the pivotal axis of the contact carrier, the said tension spring being shiftable to overcenter positions with respect to the pivotal axis of said carrier in response to pivotal movement of said lever, thereby causing movement of the contact carrier with a snap action, a contact mounted on said carrier, a second contact engageable With the contact on said carrier, and 10 means including a latch for moving the second contact to engageable and non-engageable positions in response to circuit overload conditions.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,190,517 Jennings Feb. 13, 1940 2,240,189 Linde t a1. Apr. 29, 1941 2,367,382 Taylor Jan. 16, 1945

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