Means For A Retaining A Circuit Breaker Handle In On Position While The Circuit Breaker Contact Arms Are Latched In Off Position

Abstract

The circuit breaker has an enclosure with a cover. An exterior operating handle is pivotally mounted on the cover for swinging in a path alongside the outer face of the cover to and from ON and OFF positions, selectively. A latching detent carried by the handle is movable relative thereto toward and away from the cover and is biased away from the cover by a spring. The cover carries an abutment positioned in said path. When the handle is swung along the path while the detent is in the retracted position, the detent can pass the abutment. The abutment is close to the ON position of the handle and can engage the detent when the handle is moved slightly from ON toward OFF position while the detent is in extended position. The force of the biasing spring is such that frictional resistance of the engaged surfaces of the detent and abutment can overcome the biasing force of the detent spring and thereby hold the detent member in extended position and thereby the handle in ON position, so long as a predetermined minimum applied force is applied to the handle in a direction to bias the handle in the OFF direction. The spring can retract the detent when the applied force becomes less than said predetermined minimum. The applied force is applied by toggle springs of the operating mechanism of the circuit breaker which springs have been preconditioned, by the movement of the handle to ON position, while the circuit breaker contact arms are latched in OFF position, for moving the contact arms of the circuit breaker to ON position when the arms are released.

Description

BACKGROUND OF INVENTION

1. Field of Invention

An external switch operating handle with a spring biased latching detent frictionally held in latching position against the force of its biasing spring.

2. Description of Prior Art

Heretofore, circuit breaker casings have been provided with a cover carrying an external operating handle which is swung in a path alongside the front face of the cover to ON and OFF positions for moving the circuit breaker contact arms to corresponding positions.

Such a structure is shown in U.S. Pat. No. 3,500,668, issued Mar. 17, 1970, and entitled "Switch Enclosure with External operating Handle and Handle Locking Assembly." Therein the cover has an abutment engageable by a latching detent carried by the handle for holding the handle in OFF position when the detent is locked by extraneous means in an extending position. The detent is spring biased to retracted position.

The multi-pole electric circuit breaker having the handle lock of the aforementioned patent includes movable contact arms which are driven to ON and OFF positions with a snap action by operating springs upon operation of the handle to tension the operating springs and then move one end of each beyond dead center in each selected direction of operation of the handle to ON and OFF positions, respectively. Such a multi-pole electric circuit breaker is disclosed in U.S. Pat. No. 3,560,899, issued Feb. 2, 1971, and entitled "Electrical Circuit Breaker with Multi-Current Rating and Improved Operating Means." As disclosed in a copending application of Robert E. Dietz and Beryl W. Layton, Ser. No. 877,668, filed Nov. 18, 1969, now U.S. Pat. No. 3,601,724, electrically operable, remotely controlled latch means are provided for latching the contact arm carriers of a circuit breaker in an open or OFF position against the force of the operating spring while the handle is held in an ON position so that the operating spring can drive the contact arms to ON position upon release of the latch while the handle remains in the ON position.

SUMMARY

The present invention is directed to an external operating handle such as described in the above U.S. Pat. No. 3,500,668, but with an abutment, or additional abutment as the case may be, positioned so that it cooperates with a handle carried detent to hold the operating handle in the ON position while the handle is biased toward OFF position by the toggle springs of the operating mechanisms of the circuit breaker due to latching of the contact arm carriers thereof in an open position, as disclosed in the above application, Ser. No. 877,668 of Nov. 18, 1969, now U.S. Pat. No. 3,601,724.

DESCRIPTION OF DRAWING

FIG. 1 is a front elevation of a molded-case circuit breaker embodying the principles of the present invention, with the operating handle in the OFF position;

FIG. 2 is a view similar to FIG. 1 showing the operating handle latched in the ON position;

FIG. 3 is a cross sectional view taken on the line 3--3 in FIG. 2, but showing a latching detent in retracted position;

FIG. 4 is an enlarged fragmentary sectional view taken on the line 4--4 in FIG. 2;

FIG. 5 is an enlarged fragmentary view taken on the line 5--5 in FIG. 2; and

FIG. 6 is an enlarged fragmentary view taken on the line 6--6 in FIG. 4.

Referring to FIGS. 1 and 2 of the drawing, a multi-pole molded-case circuit breaker 1 similar to that disclosed in the aforementioned U.S. Pat. No. 3,560,899 is shown.

The circuit breaker 1 includes a case having side walls 2 and a cover 3 with a front wall 4. The interior structure is described in detail in the aforementioned U.S. Pat. No. 3,560,899. Latching means 6, as disclosed in the aforementioned copending application, Ser. No. 877,668, now U.S. Pat. No. 3,601,724 are provided for releasably latching the contact arm carriers in open or OFF position.

A cross bar 7 is connected to the operating mechanisms of all three poles of the circuit breaker and to a suitable linkage, indicated generally at 8, which, in turn, is drivingly connected to a rocker arm 9 mounted on a rock shaft 10 extending through the cover 3.

The circuit breaker 1 includes an exterior operating handle 11 which is fixedly mounted on the rock shaft 10. The handle 11 may be swung to ON position for tensioning the springs of the operating mechanisms of the circuit breaker while the contact arm carriers are latched in an OFF position by latching means, such as disclosed in the aforementioned copending application Ser. No. 877,668, now U.S. Pat. No. 3,601,724 whereby the handle 11, while in the ON position, is biased toward the OFF position by the toggle springs so long as the contact arm carriers are latched in OFF position.

The specific details of the interior structure of the circuit breaker 1 and of the latching means 6 form no part of the present invention, which is directed to the operating handle 11 and the latching means therefor.

As mentioned, the handle 11 is operable to swing the arm 9 and thereby the cross bar 7 to ON and OFF positions, selectively, and to be swung by the arm 9 from an ON to an OFF position when the contact arm carriers of the circuit breaker 1 are latched in OFF position by the latching means 6. Further the circuit breaker 1 is one in which, while the movable contact arm carriers are latched in the open or OFF position by the latching means 6, the cross bar 7 is biased to the OFF position by the toggle springs of the operating mechanisms of the circuit breaker. This biasing force of the toggle springs is transferred through the linkage 8, rocker arm 9, and rock shaft 10 to the operating handle 11 so as to bias the operating handle 11 to swing about the axis of the shaft 10 to the OFF or open position of the circuit breaker, such as indicated in solid lines in FIG. 1.

The handle has an outer end portion 15 in which a detent 12 is arranged for engagement with and disengagement from a suitable abutment on the front wall 4 of the cover 3. The detent 12 and all mOving parts thereof, and their mounting in a cavity in the outer end portion 15 of the handle 11 may be the same as in the aforementioned U.S. Pat. No. 3,500,668.

The detent 12 comprises a flat piece of metal supported in the handle 11 by a pivot 13 disposed in an elongated slot 14 in the detent 12 so that the detent can be swung about the pivot 13 toward and away from the cover 3 and also can be pulled slightly outwardly endwise of the handle. For the purpose of locking the detent 12 in extended position, should such be desired, it is provided with an elongated slot 16 (FIGS. 3 and 5) arranged to receive hasps of one or more padlocks. The detent 12 is provided with a finger 17 which, while the handle 11 is in OFF position, can be moved into a slot 18 in the cover by moving the detent to extended position and when so moved, is engageable with a side wall 19 of the slot 18 for holding the handle in the OFF position. The detent 12 may be used to lock the handle 11 in OFF position by suitable padlocks or to hold it in ON position, selectively.

The handle and detent structure thus far described is fully disclosed in the aforementioned U.S. Pat. No. 3,500,668.

In accordance with the present invention, means are provided which cooperate with the detent 12 to hold the handle 11 in the ON position against the biasing force of the toggle springs of the circuit breaker operating mechanism. For this purpose, the cover 3 is provided with a recess 20 in which an abutment 21 is adjustably mounted. The abutment 21 is secured in adjusted positions along the path of the outer end portion 15 of the handle 11 by a screw 22 extending through an elongated slot 23 in the abutment. The abutment 21 is positioned near the ON position of the handle 11 so that, if the handle is swung to the ON position and the detent 12 moved to extended position, the detent finger 17 will lie closely alongside the abutment 21. When the handle 11 then moves a very slight distance toward OFF position under the biasing force of the toggle springs, the side of the detent finger 17 facing toward the OFF position of the handle 11 will engage the abutment 21 and prevent swinging of the handle 11 to the OFF position so long as the detent 12 is extended.

The detent 12 is biased toward a retracted position by a spring 24, as described in the aforementioned U.S. Pat. No. 3,500,668. The spring is chosen for the present purposes in relation to the biasing force imposed on the handle 11 by the toggle springs of the circuit breaker operating mechanisms when the handle is in ON position and the movable contact arm carriers are latched in the OFF position by the latching means 6. This relation is such that the frictional force between the side of the finger 17 and the juxtaposed face of the abutment 21 is enough to restrain movement of the detent 12 to retracted position by its biasing spring 24. Accordingly, if the handle 11 is moved to ON position while the circuit breaker contact arms are latched in OFF position, the biasing force of the toggle springs of the circuit breaker operating mechanisms will urge the handle 11 toward the OFF position. This biasing force is such that the frictional resistance to movement of the detent 12 toward retracted position overcomes the force of the spring 24, whereby the detent remains in the extended position and latches the handle 11 in ON position. If the latching means 6 is operated to release the circuit breaker contact arms, the biasing force of the circuit breaker operating mechanisms toggle springs biasing the handle 11 to OFF position is eliminated. As a result, the pressure between the finger 17 and abutment 21 is reduced below a predetermined minimum value whereupon the spring 24 is adequate to, and does, retract the detent 12 and thereby releases it from the abutment 21. The handle 11 is then free to be swung to OFF position and operated in the usual manner.

It is apparent, therefore, that by the use of the detent structure disclosed in the aforementioned U.S. Pat. No. 3,500,668 with an abutment in the proper position, the handle 11 can be releasably held in the ON position, thereby providing a very simple and effective means for retaining the handle 11 in ON position so long as the contact arms are latched in open or OFF position.

Claims

Having thus described my invention, I claim:

1. An electric circuit breaker including a handle member;

a supporting member supporting the handle member for movement along a predetermined path, extending alongside one face of the supporting member, to and from ON and OFF positions, respectively;

contact carriers;

operating mechanism for the carriers including springs which, while the carriers are latched in OFF position while the handle is in ON position, bias the handle toward OFF position with a predetermined force;

a latching detent element mounted on one of the members for movement transversely of said path relative to said one of the members toward and away from the other of said members to extended and retracted positions, respectively;

spring means biasing the detent element to retracted position and normally holding the detent element in retracted position;

an abutment element connected to the other of said members and positioned so that the detent element, while in extended position, is in alignment in a direction along said path with the abutment element, and said elements have complementary abutment surfaces which, while the detent element is extended, can be engaged when the handle member is moved along said path to a predetermined position;

said abutment element being positioned to clear the detent element while the detent element is in said retracted position during movement of the handle member along its said path;

characterized in that:

the one of said elements on the supporting member is positioned along said path close to the ON position of the handle member and has its abutment surface facing in a direction along said path toward the ON position and, in the extended position of the detent element, faces the abutment surface of the other element and is aligned therewith endwise of the path;

the strength of the detent biasing spring is such that (a) the frictional resistance of said abutment surfaces to movement of the detent element by the spring to retracted position while the surfaces are held in engagement by said predetermined biasing force applied to the handle member and biasing it toward OFF position, can overcome the biasing force of the detent biasing spring and thereby hold the detent element in extended position and the handle member in ON position so long as said predetermined biasing force is applied, and (b) the detent biasing spring can overcome said frictional resistance and retract the detent element when said predetermined biasing force is removed.

2. The structure according to claim 1 wherein the detent element is carried by the handle member, and the abutment element is carried by the support.

3. The structure according to claim 2 wherein the abutment element is mounted on said supporting member for adjustment to preselected positions along the path of the handle member.

4. The structure according to claim 2 wherein abutment means are provided on the supporting member near the OFF position of the handle member, and are arranged for engagement with the detent element, when the detent element is in extended position and concurrently the handle member is in OFF position, for latching the handle member in the OFF position.