US2981812A - Circuit breaker - Google Patents

Description

April 25, 1961 B. A. PITEO, JR, ETAL 2,981,812

CIRCUIT BREAKER Filed July 31, 1958 2 Sheets-Sheet l F9 3 IN VEN TORS BENJAMIN A. PIT-E0 Jm, DAVID B Powzu.

A TTORNEY April 25, 1961 B. A. PITEO, JR., ETAL 2,981,812

CIRCUIT BREAKER Filed July 51, 1958 2 Sheets-Sheet 2 INVENTORS BENJAMIN A. Pnzo JR.

DAVID B. powzu. BY WM 1* 7 ATTORNEY United States Patent CIRCUIT BREAKER Benjamin A. Piteo, Jr., Forestville, and David B. Powell, Bristol, Conn., assignors to General Electric Company, a corporation of New York Filed July 31, 1958, Ser. No. 752,273

2 Claims. (Cl. 200-114) Our invention relates to electric circuit breakers and particularly to circuit breakers including auxiliary devices for the purpose of providing remote indication or control in accordance with the condition of the circuit breaker mechanism.

There are four types of auxiliary devices commonly used in connection with electric circuit breakers. These are:

(1) Auxiliary switches (2) Trip alarms (3) Undervoltage trip devices (4) Remote trip devices Auxiliary switches are switches incorporated within the circuit breaker casing which are actuated upon movement of the circuit breaker mechanism to the open-circuit or otF condition, thereby controlling a remote device or indicator accordingly.

Trip alarms are special types of auxiliary switches which are incorporated within the circuit breaker casing and are actuated upon movement of the circuit breaker mechanism to the tripped or automatically opened position, such as in response to an overload or short-circuit condition in the circuit controlled by the circuit breaker.

Undervoltage trip devices are devices incorporated within the circuit breaker casing which act, when the voltage existing in the circuit controlled by the circuit breaker decreases below a predetermined value, to trip or automatically open the circuit breaker, usually for the purpose of preventing damage to electric motors which would be injured by running in a condition of low voltage.

Remote trip devices" are devices incorporated within the circuit breaker casing which act in response to the closing of a remotely located switch to cause automatic opening of the circuit breaker mechanism. They provide a convenient means for disconnecting a circuit in an emergency, from a predetermined remote location.

Electric circuit breakers of the type referred to herein include an insulating casing of molded plastic material, and are provided in twoand three-pole forms, the insulating casing comprising elongated substantially isolated chambers corresponding in number to the number of poles. Thus a two-pole breaker comprises an insulating casing having two side-by-side elongated chambers and a three-pole breaker comprises an insulating casing having three side-by-side elongated chambers.

In the construction of such circuit breakers, it is conventional practice to provide in each of such chambers at least one relatively stationary contact and one relatively movable contact carried by a pivotally supported contact arm, and, in addition, in one of such chambers, an operating mechanism disposed and arranged to operate all of such contact arms between open and closed circuit positions either (a) manually by means of an operating handle, or (b) automatically by means of a releasable member normally held by a latch member which in turn is releasably held by a trip" device actuated in response to abnormal electrical conditions in the circuit controlled by the circuit breaker to release the latch member.

2,981,812 Patented Apr. 25, 1961 Because of the presence of the operating mechanism in one pole chamber of the circuit breaker, in addition to the contacts and contact arm, the room available therein for auxiliary switches or other devices is extremely limited. In accordance with the prior art, therefore, all such auxiliary devices including auxiliary switches, trip alarms, undervoltage trip devices, and remote trip devices have, because of their size and construction, necessarily been located only in the pole chambers of such breakers not occupied by the operating mechanism. The number and combination of such auxiliary devices which can be used in such breakers according to the prior art is therefore extremely limited. For example, if it is desired to utilize an auxiliary switch and a trip alarm device in a three-pole breaker, both chambers not occupied by the operating mechanism would have to be utilized. This renders it impossible, therefore, to also provide in the same breaker, an undervoltage trip device or a remote trip device. Similarly, when any one of the four abovelisted auxiliary devices is incorporated in a two-pole circuit breaker in accordance with the prior art, the one available pole chamber must be utilized and no other auxiliary device can be provided in the same breaker.

Moreover, auxiliary switch constructions provided by the prior art require specially constructed switching assemblies which are relatively large and of relatively high cost.

It is an object of the present invention to provide a circuit breaker construction incorporating auxiliary devices utilizing standard commercially available inexpensive switches.

It is another important object of the invention to provide a circuit breaker construction incorporating auxiliary devices including a trip alarm device which can be mounted in the same pole chamber as that occupied by the operating mechanism of the circuit breaker.

It is another object of the invention to provide a circuit breaker construction incorporating auxiliary switches wherein a relatively large number of such switches may be provided in a single circuit breaker.

It is a further object of the invention to provide a circuit breaker construction incorporating auxiliary switches wherein the auxiliary switches and operating means therefor may readily be added to or removed from the circuit breaker and wherein one or more switches may be utilized and operated by the same operating member.

In accordance with the invention, an electric circuit breaker is provided including at least two relatively movable contacts and an operating mechanism therefor including a member movable between two predetermined positions in accordance with movement of one of said contacts between open and closed circuit position. Support means is provided for mounting a plurality of auxiliary switches each having an operating member of the push-button type, the operating members being aligned in side-by-side relation. in a row. A fiat spring member is mounted at one end in the circuit breaker and is arranged to be deflected by the said movable member upon its movement to a predetermined position. An intermediate portion of the resilient member engages and operates the operating members of the auxiliary switches, and the resilient member is provided of sufiicient width to engage and operate the operating members of all the auxiliary switches simultaneously.

In accordance with the invention in one form, an auxiliary switch is supported in the same pole section as the circuit breaker operating mechanism and a resilient fiat spring operator is provided which includes a part projecting into the path of a releasable or tripping member of the circuit breaker mechanism so as to be operated upon tripping of the circuit breaker.

The aspects hereof considered to be novel will be particularly pointed out in the appended claims. The construction and operation of the invention in specific embodiments however will be clearly understood from the following detailed description taken in conjunction with the accompanying drawings in which:

Figure l is a side elevation view of an electric circuit breaker incorporating the invention, a portion of the side wall of the insulating casing thereof being broken away;

Figure 2 is a fragmentary top plan view showing a portion of the circuit breaker of Fig. 1;

Figure 3 is a fragmentary side elevation view of a second embodiment of the invention, shown in connection with a different circuit breaker;

Figure 4 is an exploded perspective view of the auxiliary switch and its associated operator utilized in the form of Figure 3;

Figure 5 is a side elevation view of a third embodiment of the invention, applied to a circuit breaker similar to that of Figure 3;

Figure 6 is a top plan view of a portion of a circuit breaker as shown in Figures 3 and 5;

Figure 7 is a perspective view of an auxiliary switch assembly including its associated support and operator as utilized in the form of Figure 5;

Figure 8 is a view of the interior of one of the auxiliary switches.

In the drawings, the invention is shown in Figure l as incorporated in an electric circuit breaker 10 comprising a. generally rectangular insulating casing having a base portion 11 and a removable cover portion 12. For convenience the construction of a single pole chamber of the circuit breaker 10 is shown and will be described in detail. It will be understood however that the circuit breaker 10 includes three pole chambers, all substantially identical except that the center pole chamber contains the operating mechanism. Each pole section includes a pair of relatively stationary contacts 13a and 13b and relatively movable contacts 140 and 14b. The movable contacts 14a and 14b are both carried by contact arm 15 which is pivotally supported at 16 on the insulated base. The movable contacts 140 and 14b are connected by flexible conductive braids 17 to a terminal strap 18 of removable trip unit 19 which in turn is connected to load terminal 21 by means of strap 20. The relatively stationary contacts 13a and 13b are both mounted on a conductive strap 22 which is connected to line terminal 23.

The electric circuit through each pole section may therefore be traced as follows: from line terminal 23 to conductive strap 22, to stationary contacts 13a and 13b, to relatively movable contacts 14a and 14b, to flexible conductors 17, to strap 18, to trip unit 19, to strap 20, to load terminal 21.

For the purpose of operating the contact arm 15 and its movable contacts 14a and 14b to open and closed circuit position, a suitable operating mechanism, not shown, is provided, having an operating handle, 24, projecting through an aperture in the top wall of the circuit breaker cover 12. The operating mechanism may, for example, be as shown in Patent Number 2,921,169 issued January 12, 1960, to E. B. Judd and I. D. Young, and assigned to the same assignee as the present invention. The three movable contact arms 15 of the three-pole sections are ganged together for movement as a unit by means of a cross-bar 25 rigidly attached to each of the arms 15.

For the purpose of providing a plurality of auxiliary switch means which shall be in one condition when the circuit breaker is in the off position and in another condition when the circuit breaker is in the on position, the circuit breaker also includes the following structure. Auxiliary switch supporting means is provided comprising a sheet metal support bracket 26 which is attached to the trip unit 19 by suitable means such as by bolts 27. The bracket 26 is generally L-shaped and has a portion in flatwise engagement with the trip unit 19 and a portion extending at right angles thereto.

A plurality of miniature push-button actuated switches 28 are attached to the bracket 26 by means of bolts 29. Referring particularly to Figure 8, each of the switches 28 comprises an insulating casing formed of two matching insulating halves 30 retained together by means of a rivet 31 passing through an aperture 32 in the casing halves. Each of the switches 28 includes two opposed stationary contacts 33 and 34 mounted on terminal members 35 and 36 respectively, and a movable switch member 37 pivotally supported in the casing and electrically connected to the terminal 38. The movable switch member 37 is biased to one side of its pivot by over-center leaf spring 39 and the switch member 37 is adapted to be operated by a rectilinearly moving push-button operating member 40. The construction and arrangement of the switch is such that in the absence of any actuating force on the operating member 40, the switch member 37 is biased into engagement with the stationary contact 34 by the action of the overcenter spring 39. Upon inward movement of the operating member 40, the contact member 37 suddenly snaps over-center and is biased into engagement with the stationary contact 33 and is held there so long as the operating member 40 is held in the inward-most position. Upon release of the operating force on the operating member 40, the inherent bias of the spring moves the switch back over-center into engagement with the stationary contact 34. The switch 28 also includes aligned apertures 41 in the insulating casing halves through which the mounting bolts 29 extend.

The switches 28 are mounted on the bracket 26 by means of the mounting bolts 29 with two switches on each side thereof. For the purpose of providing adequate over-surface or creepage electrical insulation between terminals of adjacent switches 28, a sheet insulating barrier member 43 is provided between each adjacent pair of the switches 28. The switches 28 are, moreover, mounted on the bracket 26 in the same general relation so that the operating members 40 are in side-by-side alignment in a row. The switches 28 have their terminal members 36, 35 and 38 connected by means of conductors 47 to suitable external control devices extending through an aperture 49 in the side wall of the base 11 adjacent its line of meeting with top 12.

For the purpose of actuating the switches 28, a generally L-shaped member 44 of thin resilient metallic material is provided, attached at one end to the contact arm 15 by means of rivets 45 and having its other end extending generally at right angles to the contact arm with the free end portion thereof disposed adjacent but spaced away from the contact operators 40 of switches 28.

The operation of this embodiment is as follows: when the circuit breaker is in the circuit closed or on" position, as shown in Figure 1, member 44 is spaced away from the operators 40 and the switches are therefore all in the position in which the movable contact is in contact with the stationary contact 36. When the circuit breaker contact arm 15 is moved to the oli or opencircuit position, whether moved manually by means of the handle operating member or by means of the circuit breaker trip device, the resilient operator 44 is moved into engagement with the plunger members 40 and actuates all switches to the opposite position. The resilient member 44 is accordingly made sufliciently wide to actuate all four of the switches 28 mounted above that particular contact arm. When the contact arm 15 is returned to the circuit closed or on position, the switches 28 return to the opposite condition as previously described.

It will be observed that by means of the construction herein provided, it is possible to provide any desired number of switches 28 from one to four, which can be operated by means of a single operating member 44 of simplified construction.

As illustrated in Figure 6, it is therefore possible to mount and operate as many as eight auxiliary switches in a three-pole breaker, four being mounted in each of the outside pole sections of the breaker. The switches 28 are of standard commercial construction and require no special adaptation, and no special ganging operating mechanism is necessary to operate all such switches at once. Additionally, because of the resilient nature of the operator 44, the positioning and adjustment of the switches 28 is not critical.

In Figures 3 and 4 there is shown a form of the invention adapted to serve as a trip alarm.

This form of the invention is shown as embodied in an electric circuit breaker 50 having an insulating casing including a base portion 51 and a cover portion 52, a movable contact arm 53, and a stationary contact 54. An operating handle 55 is provided for operating the contact member 54 between open and closed circuit posi tions, by means of an operating mechanism shown generally at 56.

The movable contact arm 53 is pivotally supported in the frame 57 on the pivot 58. A pair of toggle links 59 and 60 are interconnected at pivot 66 and are pivotally connected at one end 61 to the contact arm 53 and at the other end 62 to a trip member or releasable member 63, which in turn is pivotally supported on the frame 57 at pivot point 64. The releasable member 63 is normally restrained in the solid line position by suitable latch restraining means, 63a, adapted to be operated by a trip device 65. The manually operable handle member 55 is pivotally supported on the frame 57 at pivot point 67 and has a main operating tension type spring interconnected between point 68 on the handle member and toggle knee point 66 of the toggle linkage. Movement of the operating handle 55 between its extreme positions therefore moves the line of action of the tension spring 69 from one side to the other of the pivot point 62 and causes the movable contact arm 53 to move between open and closed circuit position with a snap action as the toggle linkage 59 and 60 is moved between its collapsed and straightened conditions. Upon release of the releasable member 63 by the trip mechanism 65, the contact member 53 also moves to open circuit position, and the handle member 55 moves to trip-indicating position as indicated in dotted lines. For the purpose of providing a remote indication of the tripped condition of circuit breaker 50, there is provided an auxiliary switch 70 which is rigidly mounted on a supporting bracket 71 by screws or rivets, not shown, passing through apertures 79 and 80 in the bracket and switch respectively. The supporting bracket 71 is rigidly mounted on the insulating casing portion of the trip unit by means of screws 84 passing through apertures 77. The screws 84 also serve to attach an insulating barrier 82 and a flat resilient operating member 72 to the member 65 by engagement in apertures 81 and notches 83 in these members respectively. The switch 70 is provided with external terminals 76 by which it is connected to the remote indicating device. The mounting plate 71 has an elongated intermediate aperture 78 through which the terminals 76 project so that they are readily and conveniently available for connection when the cover 52 of the circuit breaker casing is removed. The resilient member 72 has an outer portion 73 and an intermediate offset portion 74 disposed adjacent to the operating member 75 of the miniature auxiliary switch 70.

Upon the release of the releasable member 63, the member 63 engages the end 73 of the resilient operator 72 and deflects the same, causing the intermediate portion 74 to engage the operator 75 to operate the switch 70, thereby giving a remote indication of the tripped condition of the circuit breaker.

It will be observed that this construction provides an extremely compact trip alarm switch which is mounted in the same pole chamber as the breaker operating mechanism, thus leaving the two other pole chambers of a three-pole breaker free to accept other auxiliary switches or other auxiliary devices such as an undervoltage trip device or a remote trip device.

In Figure 5 there is shown another embodiment of the invention comprising a circuit breaker 86 similar to the circuit breaker shown in Figure 3, having an insulating casing comprising a base portion 87 and a cover portion 88 and a movable contact arm 89 pivotally supported upon a pivot 90 and carrying a movable contact member 91 disposed to make contact with a stationary contact member 92. The movable contact arm 89 is disposed and arranged to be moved between closed and open positions by means of a manually operable handle member 93 through the agency of a suitable operating mechanism, not shown. The circuit breaker 88 includes three contact arms 89, only one shown, which are rigidly interconnected for simultaneous operation by means of a cross-arm 94 of generally rectangular cross-section, which is rigidly attached to each of the contact arms 89. In this embodiment of the invention, means is also provided for mounting a number of auxiliary switches 28 by means of bolts 96 upon a generally L-shaped metallic supporting bracket 97 rigidly attached to the insulating casing of a removable trip unit 98 by suitable means such as by screws 99 in a manner generally similar to that of the form of Figures 1 and 2.

For the purpose of actuating the switch operators 40 simultaneously in response to movement of the contact arms 89, there is provided an angular resilient metallic member 100 which is rigidly attached to the angular bracket 97 by suitable means such as by rivets 101.

The switches 28 are mounted on the bracket 97 by bolts 96, insulating barriers 102 being provided between each of the adjacent switches and the barrier 97.

in operation, so long as the movable contact arm 89 is in the closed circuit position indicated in Figure 5, the operating member 180 is out of engagement with the plunger type operator 40 and the switches 28 are therefore in a first condition in which the movable contact member 39 is in engagement with the normally stationary contact 36 or normally closed. Upon movement of the contact member 89 to the open-circuit position, indicated in dotted lines in Figure 5, the cross arm 94 rotates about the pivot 90 to the position indicated in dotted lines and moves member 100 into engagement with the operator members 40 of the switches 28, moving them to actuated condition.

The form of the support assembly indicated in Figure 7 is generally similar to the form of Figures 5 and 6, although only two switches are shown mounted thereon. It will be understood of course, that any desired number of switches from one to four may be mounted on the supporting member 97. The operating member 100 is provided of a Width at least equal to that required to operate all the operating members simultaneously, as indicated in Figure 6. For the purpose of providing the desired degree of resilience, there is provided an enlarged aperture 104 in the member 100 adjacent the bend thereof.

As indicated in Figure 6, a supporting member 105 is provided for use in the pole section of the circuit breaker opposite from that wherein the support 97 is mounted. The support member 105 is shown as generally similar to support 97, but substantially the mirror image thereof. By the compact and efiicient mounting provided herein, it will be observed that as shown in Figure 6, it is possible to mount at least eight auxiliary switches in a circuit breaker of the type shown using only the two outside pole sections. The auxiliary switch of the form of Figure 3 which is operated only upon tripping operation of the circuit breaker, and which is mounted and supported in the central chamber, may, of course, be used in addition to the auxiliary switches shown in Figure 6. There is therefore provided by the present invention, an extremely wide latitude of combinations of auxiliary switches which may be mounted in and operated by the mechanism of a conventional circuit breaker.

It will also be observed that the assembly illustrated in Figmre 7 comprising the support member 97 (or its equivalent 105) and the operating member 100, together with the auxiliary switches mounted on the bracket, constitutes a subassembly which may be easily manufactured and sold for addition to existing circuit breakers.

While there has been shown and described only three specific embodiments of the invention, it will be readily appreciated that many modifications thereof may be made, and it is therefore intended by the appended claims to cover all such modifications as fall within the true spirit and scope of the invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. An electric circuit breaker comprising an insulating casing having at least one operating pole chamber, a relatively stationary contact member mounted in said pole chamber, a movable contact arm pivotally supported in said pole chamber, a supporting plate of relatively thin sheet metallic material rigidly mounted on said insulating casing and including a portion projecting in edgewise relation over said contact arm in said pole chamber, at least one miniature auxiliary switch mounted on each of the opposite planar surfaces of said projecting portion of said supporting plate in said pole chamber in alignment with each other transversely of said contact arm, each of said auxiliary switches having a plunger type operating member, the operating members of all of said auxiliary switches being aligned in a row, and an operating member of thin flat resilient material having one end thereof rigidly mounted on said contact arm and having the other end thereof disposed adjacent said operating members of said auxiliary switches, said resilient operating member being moved by said movable contact arm and engaging said plunger type operating members of all of said aux iliary switches substantially simultaneously when said con tact arm is moved to disengaged position.

2. An electric circuit breaker as set forth in claim 1 wherein said resilient operating member has one end rigidly supported on said auxiliary switch supporting plate and has its other end disposed adjacent said plunger type operating members.

References Cited in the file of this patent UNITED STATES PATENTS 2,416,407 Runke Feb. 25, 1947 2,468,645 Steinmayer Apr. 26, 1949 2,512,386 Sandin et al June 20, 1950 2,656,439 Gelzheiser et al Oct. 20, 1953 2,760,028 Walker Aug. 21, 1956

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