Handle Tie For Push-push Circuit Breakers

Abstract

A non-removable handle tie is connected to a pair of push-push type circuit breakers arranged in back-to-back relationship. The handle tie includes a central finger engageable portion and oppositely extending offset sections entered into cavities of the circuit breakers through rear openings into the cavities. Both the stamped metal and molded plastic constructions for the handle tie are loosely connected to the circuit breaker handles to permit tilting of the handle tie when both handles are not in corresponding positions, yet this connection permits simultaneous manual operation of both circuit breakers. In the molded resilient construction of the handle tie the unit is formed so as to experience controlled bending when the handles are not in corresponding positions. However, when the handle tie is depressed for manual operation, the handle tie exhibits rigidity in transmitting operating forces.

Description

This invention relates to circuit breakers that are manually operable to ON and OFF positions by successively depressing their operating handles, and more particularly relates to novel means for tying the handles of adjacent circuit breakers to permit simultaneous manual operation thereof, and permitting the handle of a tripped circuit breaker to move to TRIP indicating position and at the same time permitting the handle of the other circuit breaker to remain in its ON position.

Many electrical devices require an individual circuit breaker in each of two energizing line thereof. It is desirable, and sometimes required, that both circuit breakers be manually operable simultaneously to their ON and OFF positions, yet under fault conditions it is desirable to have an indication of which circuit breaker was subjected to fault conditions.

Until recently, to achieve simultaneous manual operation it was permissible to have the circuit breaker handles in close proximity, say spaced by one-sixteenth inch. However, with this arrangement it was found that on many occasions an operator failed to bridge the gap between handles and only one of the circuit breakers was operated. Thus, the national electric code (NEC) has been revised so as not to deem acceptable for simultaneous operation circuit breaker arrangements in which the operating handles are not tied together.

Accordingly, this invention relates to novel tie means that engages both handles of a pair of circuit breakers that utilize depressible handles, which upon successive operations thereof alternately open and close the circuit breaker contacts. The tie means of the instant invention comprises members that are inserted into open-sided cavities in circuit breaker handles. Two embodiments of the instant invention include rigid single-piece constructions in which the tie members are tiltable so as to permit both simultaneous and independent operation of the circuit breaker units, as required. In another embodiment of this invention, a single-piece semi-rigid handle tie member is provided. This member is so constructed that it acts as a rigid unit when force is exerted thereon to depress the circuit breaker handles. However, certain portions of this member are relieved to facilitate bending as required to accommodate different handle positions.

Accordingly, a primary object of the instant invention is to provide novel handle tie means for adjacent circuit breakers.

Another object is to provide tie means of this type that is not dismountable from the circuit breakers.

A further object is to provide tie means of this type constructed of a single element.

A still further object is to provide tie means of this type that is readily inserted into retaining cavities in the handles of adjacent circuit breakers that are mounted back to back.

A still further object is to provide tie means of this type that is a stamp metal member, a rigid member constructed of plastic, and a semi-rigid flexible elastic tie handle constructed of rubber-like material.

These objects as well as other objects of this invention will become readily apparent after reading the following description of the accompanying drawings in which:

FIG. 1 is a perspective of a single pole so-called push-push type circuit breaker.

FIG. 2 is a plan view of the circuit breaker of FIG. 1, looking in the direction of arrows 2--2 of FIG. 1, with the back cover removed.

FIG. 3 is a side elevation showing two of the pole units of FIGS. 1 and 2 mounted in a panelboard in back-to-back relationship with the circuit breaker handles interconnected by a tie means constructed in accordance with teachings of the instant invention.

FIG. 4 is a perspective of a handle tie constructed in accordance with teachings of the instant invention by stamping sheet metal.

FIG. 4A is a bottom view looking in the direction of arrows 4A--4A of FIG. 4.

FIGS. 5A and 5B are fragmentary cross-sections showing different positions for the handle tie means of FIG. 4, assembled with a pair of circuit breakers.

FIGS. 6A and 6B are side elevation and bottom views respectively of a stamped metal handle tie means for interconnecting four circuit breaker pole units.

FIG. 7A is a fragmentary cross-section showing a molded handle tie means constructed in accordance with teachings of the instant invention, assembled with a pair of circuit breakers.

FIG. 7B is a cross-section taken through line 7B--7B of FIG. 7A.

FIG. 7C is a plan view of the molded handle tie means, looking in the direction of arrows 7C--7C of FIG. 7A.

FIG. 8A is a fragmentary cross-section showing a resilient handle tie means constructed in accordance with teachings of the instant invention, assembled with a pair of circuit breakers.

FIG. 8B is a plan view of the resilient handle tie means looking in the direction of arrows 8B--8B of FIG. 8A.

Now referring to the figures, and more particularly to FIGS. 1-5B. Single pole push-push type switch or circuit breaker 10 is of the type described in U.S. Pat. Nos. 2,938,983 and 3,120,629. Briefly, circuit breaker 10 includes cup-shaped molded casing or housing 11 having an open rear normally closed by insulating plate or cover 12 secured thereto by ears 12a of mounting member 12b. The front of casing 11 is formed with openings through which line and load terminals 14, 15 extend. The current path through circuit breaker 10 comprises line terminal 14 having stationary contact 16 mounted thereto and disposed within the casing element, movable contact 17 mounted to one end of L-shaped contact arm 18, bimetal 19 mounted at its lower end to contact arm 18, flexible braid 20 secured to the upper end of bimetal 19, and load terminal 15.

In addition to including contact arm 18 and bimetal 19, the operating mechanism for circuit breaker 10 includes insulating cam plate 21 pivoted to housing 11 by rivet 22 which also provides a pivot for contact arm 18. Main operating spring 23, seated at its upper end against contact arm extension 24 and at its lower end against casing 11, provides operating forces to bring about both opening and closing of circuit breaker 10 with a snap action, as described in detail in the aforesaid U.S. Pat. No. 2,938,983 and patents referred to therein. The upper end of housing 11 is provided with opening 24' through which handle 25 extends. Handle 25 constitutes a push-button type actuator to bring about manual operation of circuit breaker 10. A cross-ledge of housing 11 provides a seat for coiled compression spring 27 which also bears against handle 25 to bias the same outwardly or upwardly with respect to FIG. 1. Pawl 28 of cam plate 21 cooperates with a lug-on handle 25 to limit outward movement of the latter to an intermediate position when circuit breaker 10 is closed or ON and prevent handle 25 from going to its fully projected or circuit breaker OFF position. The latter position is established through the cooperation of formations (not shown) on handle 25 and the interior of housing 11. Movement of handle 25 is also utilized to operate ON-OFF indicator 31 in the form of a plate disposed within an undercut portion of handle 25.

As best seen in FIG. 3, mounting member 12b is constructed of metal and is shaped as inverted U having extremely closely spaced arms to which a pair of push-push type circuit breakers 10--10' are mounted in back-to-back relationship. Panelboard mounting leg 51 is straddled by the arms of mounting member 12b and operatively positions the latter so that line terminals 14, 14' of the respective circuit breakers 10, 10' engage the respective panelboard bus bars 52, 52'.

Handles 25, 25' are provided with cavities 55, 55', respectively, that extend forward from the rear surfaces of handles 25, 25'. These cavities 55, 55' receive the generally V-shaped extensions 71, 71', respectively, of handle tie 70, the latter being a single-piece metal stamping. Handle tie 70 also includes centrally located main section 72 from which end sections 71, 71' extend in opposite directions. Central section 72 is offset upwardly with respect to extensions 71, 71' to a level above the tops of handles 25, 25', and is provided with central finger locating depression 73. The proportions of extensions 71, 71' and cavities 55, 55' are such that handle tie 70 is free to tilt, thereby permitting handles 25, 25' to assume different positions as in FIG. 5B, wherein handle 25' is in the fully extended OFF-TRIP position for circuit breaker 10' and handle 25 is in the intermediate ON position for circuit breaker 10.

Although not illustrated, it is noted that handle tie 70 may be tilted sufficiently to permit one of the circuit breaker handles to be fully depressed, while the handle of the other circuit breaker remains fully extended. Extensions 71, 71' are provided with curved exterior surface portions 74, 74' respectively to facilitate tilting of handle tie 70. These curved surface portions 74, 74' bear against cavity defining surfaces 76, 76' when handle tie 70 is manually depressed to operate circuit breakers 25, 25' either simultaneously or individually, as required.

As is well known to the art and described in U.S. Pat. No. 3,075,058 issued Jan. 22, 1963 to E. T. Platz et al. for a Push-Push Circuit Breaker, for lower current push-push type circuit breakers, two independently operable pole units may be housed in a casing having the same overall dimensions as casing 11. When two such twin units are mounted back-to-back on mounting member 12b, it is often necessary to operate all four pole units simultaneously. The stamped sheet metal handle tie 80 of FIGS. 6A and 6B is suitable for this purpose. More particularly, handle tie 80 includes central section 81 having finger depression 82. A pair of spaced offset generally V-shaped extensions 83a, 83b extend in the same direction from one edge of central section 81 and a similar pair of spaced offset generally V-shaped extensions 84a, 84b project in the opposite direction from the opposite edge of central section 81. Extensions 83a, 83b, 84a, 84b are so proportioned and positioned with respect to the handle cavities into which they project that any one or more of the four handles may be operated independently of the other handles and if desired all four handles may be manually operated simultaneously.

FIGS. 7A-7C illustrate molded plastic handle tie 80 including manually engageable central portion 81 having finger locating parallel grooves 82. Diverging arms 83, 83' extend downward from central section 81, and at their respective lower ends support cylindrical sections 84, 84'. The axes of the latter are perpendicular to the plane of arms 83, 83' and extend on opposite sides thereof. Cylindrical parts 84, 84' project into cavities 85, 85', respectively, of the respective handles 89, 89' through the open rear ends of these cavities. Handle 89 is provided with groove 86 and slot 87 which receive and guide movement of arm 83. Similarly, handle 89' is provided with groove 86' and slot 87' which receive and guide movement of arm 83'.

FIGS. 8A and 8B illustrate semi-rigid handle tie 90 molded of hard rubber-like material. Handle tie 90 includes manually engageable central portion 91 having handle locating slotted portion 92 in the upper surface thereof and offset extensions 92, 92' projecting in opposite directions into handle cavities 55, 55' through the open rear thereof. Handle tie 90 is cut away or relieved at areas designated 93, 93' and is provided with transverse slits 94, 94' all of which facilitate bending of extensions 92, 92' relative to central section 91 as required when handles 25, 25' are in different operating positions. However, handle tie 90 is sufficiently rigid so that it may not be dismounted from circuit breakers 10, 10' without dismounting at least one of these circuit breakers from mounting member 12b. Further, handle tie 90 is sufficiently rigid so that when a downward force is applied at grooved area 92, this force will be transmitted to handles 25, 25' for operation of circuit breakers 10, 10'.

Thus, it is seen that the instant invention provides novel, inexpensive constructions for handle ties that interconnect a pair of back-to-back mounted push-push type circuit breakers, with the handle ties being so constructed that the circuit breakers may be manually operated simultaneously or individually as desired. Further, these handle ties are so constructed that they may not be dismounted from the circuit breakers without first dismounting at least one of the circuit breakers from the mounting means to which it is secured.

Although there have been described preferred embodiments of this novel invention, many variations and modifications will now be apparent to those skilled in the art. Therefore, this invention is to be limited not by the specific disclosure herein, but only by the appending claims.

Claims

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. Switch means including a first and second circuit breaker, means mounting said circuit breakers in back-to-back relationship, each of said circuit breakers including cooperating contacts and an operating mechanism for manual operation of said contacts into and out of engagement, said first and second circuit breakers including respective first and second handles for controlling the operating mechanisms of the respective first and second circuit breakers, said handles being manually depressible so that upon successive manual operations thereof said contacts alternately engage and disengage, the respective first and second handles including a first and second cavity having open sides facing each other, tie means including a central section that is manually engageable and first and second sections extending in opposite directions from opposite ends of said central section, said central section being disposed between said handles with said first and second sections extending into and being captured within said first and second cavities, respectively, said handle tie operatively constructed and operatively mounted to said handles so that the latter are operable selectively for simultaneous or independent action to both engage and disengage said contacts.

2. Switch means as set forth in claim 1 in which said first and second sections are offset in the same direction from said central section.

3. Switch means as set forth in claim 2 in which the tie means is rigid and said first and second sections are loosely fitted within said cavities, whereby said tie means is tiltable as said handles are operated independently of each other.

4. Switch means as set forth in claim 3 in which said first and second sections include respective first and second curved surfaces that engage boundary forming portions of the respective first and second cavities as said tie means is depressed.

5. Switch means as set forth in claim 4 in which the tie means is constructed of a single piece of sheet material.

6. Switch means as set forth in claim 4 in which the first and second curved surfaces are portions of respective first and second generally cylindrical sections that are parallel and laterally offset.

7. Switch means as set forth in claim 2 in which the tie means is constructed of resilient material having deformation properties similar to rubber.

8. Switch means as set forth in claim 7 in which the tie means is of single piece construction.

9. Switch means as set forth in claim 8 in which said tie means is provided with relieved areas to control bending of said first and second sections relative to said central section when said handles are operated independently of each other.

10. Switch means as set forth in claim 1 also including a third and fourth circuit breaker generally of the same construction as said first and second circuit breakers and mounted in back-to-back relationship, said tie means also including third and fourth sections extending from said central section generally parallel to the respective first and second sections, said third and fourth sections extending into and being captured within handle cavities of the respective third and fourth circuit breakers, whereby all of said circuit breakers may be operated simultaneously or selectively.