US2013827A - Circuit interrupter - Google Patents

Description

Sept. 10, 1935. o. s. JENNINGS 2,013,827

CIRCUIT INTERRUPTER v Filed Feb. 2s, 1934 5 sheets-sheet 1 ATTO NEY SePtl0, 1935. o. s. JENNINGs CIRCUIT INTERRUPTER Filed Feb. 23, 1934 3 Sheets-Sheet 2 Z1-,a- 11 715 *"7 1; 7 (i7 INVENTOR AT'TORN EY Sept. l0, 1935. o. s. JENNINGs 2,013,827

CIRCUIT INTERRUPTER Filed Feb. 2s, 1954 s sheets-sheet s Patented Sept. 10, 1935 UNITED STATES ,PATENT OFFICE Pennsylvania Application February 28, 1934, Serial No. 112,578

18 Claims. (Cl. 20C-116) My invention relates to circuit interrupters and particularly to snap acting circuit breakers for use in controlling lighting and distribution feeder circuits.

It is an object of my invention to provide an improved circuit breaker that shall be small in size and inexpensive to manufacture, and that shall be capable of quickly and satisfactorily interruptmg considerable amounts of power.

Another object of my invention is to provide an improved circuit breaker that shall be manually operable to open and to close the circuit with a snap action, and that shall be automatically operable to open the circuit independently of the position ofthe operating handle.

Another object of my invention is to provide an improved operating mechanism for use with manually operable and automatically operable circuit breakers, my improved mechanism to include a releasable connecting means intermediate the operating handle and breaker actuating means.

A further object of my invention is to provide an improved operating member for use with circuit breaker actuating mechanisms, my improved operating member to include a cam controlled lost motion connection intermediate the operating member and the actuating mechanism.

A still further object of my invention is to provide an improved method for supporting the various structural elements of a circuit breaker operating mechanism in order to reduce the physical dimensions of such a mechanism to a minimum.

A still further object of my invention is to provide an improved arc extinguishing device particularly suitable for use with snap acting circuit breakers.

Thcse and other objects of my invention will be made more apparent from the following specication and drawings which disclose a preferred embodiment of my invention.

Figure l is a sectional view, partially in elevation, of a circuit breaker embodying the principal features of my invention. The moving parts of the circuit breaker are in the closed circuit position.

Fig. 2 is a view similar to Fig. l showing the circuit breaker in the open circuit position.

Fig. 311s a view similar to Figs. l and 2 showing the circuit breaker in the tripped position.

Fig. 4 is a fragmentary sectional view showing the means utilized for pivotaliy supporting the switch arms of the circuit breaker shown in Figs.

Fig. 5 is an elevational view of the circuit breaker shown in Figs. l to 3.

Fig. 6 is a sectional view taken on the line VI-VI of Fig. 5.

Fig. 7 is a view on the line VII-VII of Fig. 5. 5

Fig. 8 is an exploded perspective view showing the principal structural elements of the circuit breaker illustrated in Figs. 1 to 3.

Figs. 9 to 13, inclusive, are diagrammatic views showing the position of the various moving elel0 ments of the circuit breaker during a tripping operation resulting from an overload condition in the controlled circuit.

Fig. 14 is an exploded perspective view of the arc extinguishing device for the circuit breaker 15 shown in Figs. 1 to 3,*and

Figs. 15 to 24, inclusive, are detail views of the various structural elements used in the arc extinguishing device shown in Fig. 14.

Ihe preferred form of my invention comprises,

generally, a base member I, of insulating material, which is utilized for supporting the U- shaped frame l of the circuit breaker actuating mechanism I, the arc extinguishing device 1, the circuit breaker terminals 0 and I I, the stationary 25 -contacts I2, and the cover i3 which is also of molded insulated material. 'I'he particular embodiment shown in the drawings is of the single pole, double break type wherein the circuit is opened and' closed with a snap action. 'Ihe 30 contacts It are manually movableto the open circuit and to the closed circuit positions through the agency of an operating handle i1, and are automatically movable from the closed circuit position to the tripped position upon the occurrence of predetermined overload conditions irrespective of the position of the operating handle -i'|.

As shown particularly in Figs. l, 2, 3 and 8, the moving parts of the operating mechanism 3 40 are entirely supported upon the U-shaped frame member 5 which, in turn, is supported on the base i of the circuit breaker by means of two screws Il. The bifurcated operating handle I1 and the parallel link bell crank actuating member 2l are each pivotally supported on the frame 5 at a common pivot point by means of two pivot pins 23 which engage suitable openings therein. The two movable contacts II are carried on the ends of a pair of looped switch arms 25, which are preferably of bimetallic thermally responsive material.

These switch arms 25 carry the full line current of the circuit breaker and are joined together at the end opposite that to which thecontacts i5 55 are alxed by means of a metallic tie link 2T. A pivot pin 29 projects 'from the looped portion of each of the bimetallic switch arms 25 and is adapted to engage an insulating bushing 3| supported (as shown in Fig. 4) on one of the out wardly projecting portions 33 of the frame 5. These insulating bushings 3| are each provided with a conical shaped recess 35 (Fig. 4) for engaging the pivot pins 29.

An over-center spring 31 is provided for oper' atively connecting the bell crank actuating mernber 2i and the interconnected switch members 25. One end of the spring 31 engages a suitable opening 39 (Fig. 5) in the tie member 21, which connects the two switch members 25, and the other end engages a similar opening in the tie A.cans 4l which rigidly connects the two parallel inks which make up the actuating member lt wili. noted that the pivot points of the intercomy .ed switch members 9.5 and the actuating member 2| are spaced apar" dit tance. This is done in oder that the operation of the breaker to the open circuit and to the closed circuit positions shall be entirely automatic, once the operating handle or the electro-responsive tripping means has reached a predetermined position.

The electrical circuit through the breaker is comparatively direct. Beginning with the terminal 9 the current flows successively through the associated stationary contact I2, the cooperating movable contact l5 and its bimetallic support arm 25, the tie member 21, the second birnetallic switch member 25 and its associated moving contact I5, the other stationary contact |2, and thence to the terminal Il.

The stationary contacts I2 are preerably composed of a mixture of silver and graphite which has been pressed into a homogeneous mass. The moving contacts i5 are preferaby of pure nickel; By using insulating material for the bushings 3i upon which the assemblage of switch members is pivotally supported, any possibility of a circulating current flowing through the overcenter spring 31 or the other parts of the mechanism 3 is prevented.

The bifurcated operating hande I1 is provided with an upstanding portion 43 of insulating material, which is adapted to extend through an opening 45 in the base i of the breaker in order to permit manual operation thereof. A slidable shield plate 41 of insulating material is positioned between two metallic members 49 and 5| fastened to each other by means of suitable set screws 53, and is adapted to be moved by the operating handle I1 during the manual operation of the device, the metallic member 5| being rigidly fastened to the base I by suitable means which is not shown. This shield plate 41 serves to keep the opening 45 in the base, wherein the projecting portion 43 of the operating hande I1 moves substantially closed at all times, and is of considerable value in eliminating any possible danger to the operator which might result from outowing gases during the interruption of extremely heavy short circuits.

The lower portion of the operating handle I1 comprises a bifurcated metallic member 55 having a pair of outwardly projecting arms 51 (shown particularly in Fig. 8) and a downwardly projecting stop member 59. This downwardly projecting member 59 is adapted to provide a surface for operatively engaging the end |i| of the actuating member 2| to permit manual operation of slotted iron plates.

of the circuit breaker from the closed circuit position to the open circuit position. A cam member 63 is pivotally supported on the two outwardly projecting arms 51 by means of a pin 65 which extends through suitable openings B1 (Fig. 8) therein. The cam member 63 is biased in a counter-clockwise direction (Figs. l, 2 and 3) by means of a spring 69 and serves to provide a surface for permitting the manual operation of the breaker from the open circuit position to the closed circuit position.

In addition, as will be described in some detail later, the cam member 63 is adapted to move in such manner during the circuit closing operation that the operating handle I1 becomes coml pletely disengaged from the actuating member 2| when the breaker is in the closed circuit position, thereby permitting automatic operation of the breaker from the closed circuit to the open circuit positions irrespective of the position of the 20 operating handle I1 itself. The motion of the cam member 63 is controlled by a pin 1| which extends through the two opposed sides of the frame 5, the projecting portion 13 of the cam member being adapted to engage this pin to cause 2:

clockwise rotation of that member during the movement of the operating handle I1 from the closed circuit to the open circuit position. The upper end of the two side portions of the bell crank actuating member 2| are joined by means 3 of a tie plate 15 having a downwardly projected central portion 11 which is adapted to coact with the surface 19 of the cam member 63 during the operation of the device. i

The arc extinguisher 1 which I prefer to use 3 with this embodiment of my invention is of the spaced plate type, and comprises, generally, a stack of spaced, slotted metallic plates, preferably of iron, which are disposed adjacent the path of movement of the moving Contact members. 4 Upon the establishing of an arc, the magnetic reaction resulting from the presence of these slotted iron plates causes the arc to move into the extinguisher in the direction toward the end of the slot in each of the plates. When the arc 4 reaches the end of the slots, it is broken up into a plurality of serially connected short arcs and is soon thereafter extinguished.

Specically, the arc extinguishing device 1 comprises a stack of slotted insulating plates 5 which includ-e means for supporting a plurality These plates are shown particularly in Figs. l5 to 24, inclusive. The bottom plate 8| (Figs. 17 and 18), which is positioned adjacent the base I, is of substantially the same thickness as the stationary contacts I2 and their associated terminal strips 9 and II, and is provided with a pair of cutout portions 83 through which the terminal strips extend. In addition, it has a pair of slots 85 wherein the stationary contacts I2 are disposed, four openings 81 to perr the insertion therethrough of suitable positioiing pins 90, and a centrally disposed opening 89 to permit the passage of the main retaining screw 93 (Figs. 5, 6 and 7). One of the insulating plates 95 (shown in Figs. 21 and 22) is disposed immediately adjacent the base plate 8| in the assembled arc extinguisher. Each of the plates 95 has the four openings 81 for the positioning pins 90, the central opening 81 for the main retaining screw 93 and two rectangular slots 95 through which the moving contact members move during the operation of the interrupter. The next plate in the structure is illustrated in Figs. 19 and 20. These plates 91 are likewise of insulating material such as fibre; they have substantially the same external dimensions as the plates and 95, the openings 81 for the positioning pins Il, and the centrally disposed opening 59 for the retaining screw 03. The plates 91, however, have lrectangular slots 99 therein which are slightly larger lthan the slotted iron plates shown particularly in Figs. 23 and 24, and in the assembled Ystructures are eachA adapted to retain and lposition two of the iron plates lill. Another of the fibre retaining plates 55 is disposed on the other side of the first plate which supports the slotted iron plates llll. 'I'his in turn, is followed by another of the iron plate assemblages, a third retaining plate 95 and the fibre top plate |55, which is shown particularly in Figs. and 16. The top plate |05 is similar to the other plates in the structure in that it is of insulating material and has the openings 51 and 55 therein. However, the slots |05 in the top plate are tapered and are restricted in size so as to prevent flashovers between poles.

In this embodiment I have shown only two of the slotted iron plates |0| for each of the two arc paths. This arrangement is optional, however, and more plates may be used if the circuit characteristics warrant such use.

In the completely assembled arc extinguisher,

- the various plates are firmly pressed together by means of the retaining screws 93, which extend through the centrally disposed opening 89 therein to engage a threaded opening |51 in the U- shaped metallic member |59. This member serves the double function of supporting the arc extinguisher 1 and serving as a stop for the bimetallic switch arms 25. The retaining pins 55 which may be of insulating material are inserted in the openings 81 provided for them in order to accurately position the severalplates and to impart mechanical strength to the resultant structure.

The circuit breaker is shown in the fully closed position in Fig. l. To open the contacts manually, the operating handle I1 is moved in a clockwise direction about its pivot point, the pins 23. The downwardly projecting portion 59, which is in engagement with the portion 5| of the bell crank actuating member 2|, serves to transmit this motion to the actuating member. As the clockwise rotation of the operating handle and the actuating member 2| progresses, the line of action of the operating spring 51 is moved toward a position below the pivot point of the interconnected switch members 25 (the pins 25) and the pivot point of the actuating member (the pins 23). While this clockwise motion of the operating handle is taking place with its resultant displacement of the line of action of the overcenter spring 31, the cam member 52 is likewise rotated in a clockwise direction due to the engagement of the pin 1| and the projecting portion Il ofthe cam member itself. Shortly before the operating handle reaches the full ofi' position. the line of action of the overcenter spring is brought to a position beneath the pivot points of the interconnected switch members 25 and the actuating member 2|. 'I'he overcenter spring 31 then exerts a force which has a component tending to move the interconnected switch members 25 in a counter-clockwise direction about their pivot point and tending to move the switch actuating member 2| in a clockwise direction about its pivot point. The immediate result is to cause both of those members tomove toward the open circuit position, and, since any motion toward that position results in a progressive increase in the component of force tending to produce that motion, the opening operation takes place with a snap action. No possible impediment can be offered to this motion by the 5 vide a surface for causing movement of the 10,

actuating member.

Upon the conclusion of the manually produced circuit opening operation, the various parts of the breaker are disposed as shown in Fig. 2. It

will be noted that the clockwise rotation of the 15 cam member 53 against its biasing spring 55 produced by the clockwise movement of the operating handle I1 has caused the cam member to rotate a suillcient distance to substantially decrease the distance between the two surfaces which are used for manually operating the circuit breaker, as compared with the distance between those two surfaces when the breaker is in the closed circuit position. It will also be noted that the projecting portion of the cam member 53 is now disposed above the plate 'l5 which connects the two side portions of the actuating member 2|, thereby preventing thecam member 53 from rotating under the influence of its biasing spring 59 out of engagement with the actuat- 30 ing member. In effect, the cam member 53 serves as a releasable connection between the gperlting handle and the actuating mem- To close the circuit manually, the operating handle I'I is moved from the position shown in y Fig. 2 in a counter-clockwise direction. I'his motion is transmitted to the actuating member 2| through the engagement of the cam member 53 therewith, and as the operating handle i1 40 approaches the closed circuit position, the line of action of the spring 3l is moved above the pivot point of the interconnected switch members 25. The immediate result of this is to cause the switch members 25 to move toward the closed 45 circuit position. and since this movement results in a progressive increase in the force causing the movement, exactly as described for the opening operation, the contacts I5 move from the open circuit to the closed circuit position with a snap action. This movement of the interconnected switch members 25 brings the line of action of the overcenter spring 31 above the pivot point of the actuating member 2| and thus causes that member to disengage the cam member 55 serv- 55 ing to connect it with the operating handle and to move to the closed circuit position shown in Fig. l. When the actuating member 2| disengages the cam member 53, that member rotates freely under the influence of its biasing 50 spring 59 so as to cause a suiilcient separation of the surfaces of the operating handle which engage the actuating member to permit automatic operation of the breaker.

It will be seen that the manual operation of the circuit breaker is entirely automatic once the handle is brought to a position where the mechanism is set in motion. The circuit opening operation proceeds with a snap action, independently of any movement of the operating handle once motion from the closed circuit position to the open circuit position has been initiated, and, similarly, the closing operation proceeds entirely automatically once motion of the switch members 25 has started. 'I'he disen- 75 gagement of the actuating member 2| from the cam operated connection intermediate the operating handle I1 and the operating member also proceed entirely automatically. 5 Fig. 9 illustrates diagrammatically the position of the interconnected switch .members 25, the actuatingy member 2|, the operating handle I1,'and the line of action of the overcenter spring 31 when the circuit breaker is in the closed circuit position. Upon the occurrence of an overload in the circuit controlled by the device, the current carrying bimetallic switch arms 25 are heated and move in a direction away from each other. Since any motion in the direction of the stationary contacts I2 is prevented, the result of the heating produced by an overload is to cause the tie member 21 connecting the ends of the bimetallic switch members 25 to be moved in a direction toward the cover I3 of the circuit breaker. If the overload persists for a sucient period of time, the line of action of the overcenter spring 31 is brought to a point where it coincides with the pivot point of the actuating member 2|. This is shown diagrammatically in Fig. 10.

Then, if the heating continues sufficiently to cause the line of action to move from the position shown in Fig. 10 to the position shown in Fig. 1l, it becomes immediately apparent that the circuit breaker is in an unstable position. Thus, the overcenter spring 31 has a component biasing the actuating member 2| in a clockwise direction toward the open circuit position, a1- though at the same time it exerts a component 31.5 tending to hold the'moving contacts I5 in en- -gagement with the stationary contacts I2. This first component causes the actuating member 2I to move from the position shown in Fig. 11 to the position shown in Fig. 12, the motion of the actu- 40 ating member 2| proceeding at an increasingly rapid rate due to the progressive increase in the component producing that motion. Whenin the position shown in Fig. 12, the line of action of the operating spring 31 has been moved beneath pivot point 29 of the interconnected switch members 25 thus biasing those members from the closed circuit position to the open circuit position. The various parts of the mechanism then move to the tripped position which is shown diagrammatically in Fig. 13. It is to be understood-that Figs. l0, l1 and 12 illustrate but instantaneous positions in an operation which takes place at high speed.

As illustrated in Fig. 1, a sufiicient separation exists between the downwardly projecting member 59 and the cam member 63 intermediate the actuating member 2| and the operating handle I1 when the circuit breaker is in the fully closed position to permit the automatic move- 60 ment of the actuating member 2|, and with it the interconnected switch members 25 from the closed circuit to the open circuit position irrespective of whether the operating handle is held in the closed circuit position or not. Further,

since the cam member 63 disengages the actuating member 2| during the circuit closing operation and moves to considerably increase the distance which the actuating member may move independently of the operating handle I1, it is not possible to cause the breaker to close by holding the operating handle I1 in the closed position until the bimetallic switch members 25 have cooled. Thus, the breaker is entirely trip free of the handle both when the switch arms are in the expanded heated state and when they are mal open circuit and the normal closedcircuit 5 position and will be held in that position due to the engagement of the portion 15 of the actuating member 2| and the surface 18 of the cam member. This movement of the operating handle to a mid-position following the opening of the 10 breaker as a result of an overload or short circuit. condition provides a convenient indicating means for showing that the breaker has `been tripped.

Inasmuch as motion of the operating handle 15 |1 toward the closed circuit position will not close the breaker following a tripping operation, it is necessary to reset the mechanism following each interruption of the circuit due to the breaker being tripped. This is done by moving the han- 20 dle I1 from the position shown in Fig. 3 to the full off position which is shown in Fig. 2. Since the cam member 63 engages the pin 1| when the breaker is in the tripped position, any clockwise movement of the handle I1 toward the open cir- 25 cuit position will cause the cam member 63 to rotate clockwise about its pivot point, the pin 65 and since the surface 19 of the cam member 63 engages portion 11 of the tie plate 15 which connects the side portions of the actuating member 30 2|, any clockwise motion of the cam member 63 will cause the portion 11 of the-actuating member 2| to slide along the cam surface 19 until the projecting portion II I of the cam member has reengaged the tie plate 15 of the actuating mem- 35 ber as shown in Fig. 2. This operation may be effected through the application of a comparatively small force to the operating handle I1 and serves to completely restore the mechanism to an operative condition. The breaker may now 40 be closed manually exactly as described above.

Upon the occurrence of a very heavy overload or short circuit condition, the current owing in the looped switch members 25 may reach a sufficient magnitude to cause an actual mechanical 45 separation of the opposed side portions of those members due to the magnetic reactions set up therein. Since the only force opposing the separation of the two side portions of the-looped switch members 25 is that supplied by the con- 50 tact pressure between the stationary and the moving contacts, magnetically produced separation of the looped side portions will not result in an appreciable lessening of the contact pressure.

If the magnetically produced separation is suil- 55 cient to cause the line of action of the overcenter spring 31 to move to a position beneath the pivot point of the actuating member 2| (the position shown in Fig. 11) the circuit breaker will move to the open circuit position with a snap action 60 regardless of the position in which the operating handle may be held, exactly as described for thermostatic operation.

Whether the operation is substantially instantaneous as a result of magnetic reaction set up 65 by the flow of large magnitude currents through the looped switch members 25, or whether the operation is after a time delay due to the distortion of the switch members 25 produced by heating, is immaterial insofar as the speed of move- 70 ment of the cooperating contacts is concernedl Further, the contacts are biased together with a definite force up until the instant of contact separation. It is this feature of positive quick make and quick break regardless of the position 75 my invention from the structures heretoforel known in the art. The novel arrangement of the otfset pivot points permits the maintaining of the separable contacts in engagement under a predetermined biasing force until the instant of contact separation, as previously pointed out. and by so proportioning the several elements of the operating mechanism that the operating handle is incapable of holding the moving contacts in the closed circuit position upon the occurrence of predetermined overloads, positive opening of the circuit is assured, under any possible circuit condition.

`The downwardly projecting member Il and the cam member Il, together form a lost motion connection between the operating handle and the actuating member 2i. Thus, during the normal manual operation of the circuit breaker. the operating handle II merely serves to start the actuating member 2| in motion, the lost motion connection permitting the actuating member to move without further restraint, once a predetermined position is reached, either to the open circuit position or to the closed circuit position, independently of the movement of theoperating handle itself. 'Ihis feature is of great value in preventing improper operation of the circuit breaker which might result from a movement of the operating handle I1 in one direction immediately followed by a backing oil' of that member inthe other direction, thus causing the contacts to move slowly into and out of engagement.

'I'he adjusting screw III permits the circuit breaker to be accurately calibrated over any reasonable range of current values and also serves as a ready means for taking up any inaccuracies in the manufacture or assembly lof the parts. Since the looped bimetallic switch arms Il carry the entire line current, the heating and subsequent deilection of those members is a function of the current in the controlled circuit. Thus,

the movement of the tie member 21 which interacross the pivot point of the actuating member 2 I. As a result, the calibration of the breaker may be readily and accurately controlled or adjusted by merely changing the position of the adjusting screw H5. 'I'he magnetic opening of the breaker is dependent chiey upon the current flowing in the switch arms 25, the length of the looped portions, and their relative spacing and stiffness, the inherent resiliency of the switch arms being used as a biasing means for opposing and controlling the opening of the circuit breaker in response to the magnetic reaction set up therebetween. This feature is thus most readily changeable through tthe provision of dierent switch arms.

Particular attention is directed to the novel arrangement of the various parts of the circuit breaker operating mechanism. 'Ihe operating handle i'l and the actuating member 2| are pivoted at a single point to the frame l. The operating handle Il, the actuating member Il, and the overcenter spring l1 all move in the space between the two parallel switch arma 2l, and the frameitselfisdisposedinthatspace. Thisarrangement permits all of the available space to Abe used with a maximum of eiilciency and has made possible a circuit breaker capable of interrupting 5,000 amperes, at 115 volts, which occu- 5 pies no more space than an ordinary tumbler wall switch.

It will thus be seen that I have disclosed an improved circuit breaker which is manually operable to open and to close a circuit with a snap 1o action, and which is automatically operable to open the circuit upon the occurrence of a predetermined overload condition in the controlled circuit. Further, I have disclosed an improved means intermediate the operating handle and the l5 actuating member of a circuit breaker for varying the distance between the surfaces which engage the actuating member to assure automatic opening of the circuit regardless of the position in which the operating handle is held. I have also shown how the various structural elements of the operating mechanism may be arranged in order that the breaker shall occupy a minimum of space. Moreover, I` have disclosed an improved arc extinguishing device which is simple and inexpensive to build and which possesses a very high arc interrupting capacity.

While in accordance with the patent statutes,

I have disclosed the foregoing details of a practical embodiment of my invention, itis to be understood that many of these details are merely illustrative and that variations in their precise form will be not only possible but desirable in some applications. I desire, therefore, that the language of the accompanying claims shall be accorded the broadest reasonable construction and that my invention shall be limited only by what is stated therein and by the prior art.

I claim as my invention:

l. In a circuit interrupter, means for opening and for closing the circuit, and actuating means for said means for opening and for closing the circuit, said actuating means including an actuating member for moving said means for opening and for closing the circuit, an operating member having means for causing movement of said actuating member and having means permitting relative motion between said members during the operation of said interrupter, and means for varying the amount of said relative motion.

2. In a circuit interrupter, means for opening and for closing the circuit, actuating means for said means for opening and for closing the circuit, and electro-responsive means for causing said actuating means to move said means for opening and for closing the circuit to the open circuit position upon the occurrence of predetermined conditions, said actuating means including an actuating member for moving said means for opening and for closing the circuit, and an operating member which engages said actuating member through a lost motion engaging means having means associated therewith for varying the amount of lost motion between said members so as to permit said electro-responsive means to cause said interrupter to open the circuit irrespective of the position of said operating handle.

3. In a circuit interrupter, means for opening and for closing the circuit, and actuating means for said means for opening and for closing the circuit, said actuating means including an actuating member for operatively engaging said means for opening and for closing the circuit, and an operating member which engages said actuating member through a lost motion engaging 75 means having movable means associated therewith for controlling the amount of lost motion between said operating member and said actuating member.

4. In a circuit interrupter,n means for opening and for closing the circuit, and actuating means for said means for opening and for closing the circuit, said actuating means including an actuating member for operatively engaging said means for opening and for closing the circuit, and an operating member which engages said actuating member through a lost motion engaging means having cam means associated therewith for controlling the amount of lost motion between said operating member and said actuating member.

5. In a circuit interrupter, means for opening and for closing the.circuit, actuating means for said means for opening and for closing the circuit, and electro-responsive means for causing said actuating means to move said means for opening and for closing the circuit to the open circuit position upon the occurrence of predetermined conditions, said actuating means including an actuating member for operatively engaging said means for opening and for closing the circuit, and an operating member which engages said actuating member through a lost motion engaging means having cam means associated therewith for controlling the amount of lost motion between said members, so as to permit said electro-responsive means to cause said interrupter to open the circuit irrespective of the position of said operating handle.

6. In a circuit interrupter, means for opening and for closing the circuit, and actuating means for said means for opening and for closing the circuit, said actuating means including an electro-responsive means, an actuating member which operatively engages said means for opening and for closing the circuit and which is movable between two extreme positions to cause said means for opening and for closing the circuit to move to the open and to the closed circuit position, and an operating member for moving said actuating member from one position to the other, said operating member having means for directly engaging said actuating member to open said interrupter and means for releasably engaging said actuating member to close said interrupter, said releasable engaging means causing said actuating member to be freely movable with respect to said operating member when said interrupter is in the closed circuit position thereby permitting said electro-responsive means to cause said means for opening and for closing the circuit to move to the open circuit position irrespective of the position of said operating member.

'1..In a circuit interrupter, means for opening and for closing the circuit, and actuating means for said means for opening and for closing the circuit, said actuating means including an operating handle, an actuating member, and an electroresponsive means, said operating handle engaging said actuating member through lost motion means which permits independent motion of said operating handle and said actuating member, and having means for controlling the amount of such Y independent movement, so as to permit manual operation of said interrupter to the open circuit and to the closed circuit position, and to permit automatic operation from the closed circuit to the open circuit position in response to the operation of said electro-responsive means, irrespective of the position of said operating handle.

8. In a circuit interrupter, means movable to' open and to close the circuit, and actuating means for said means for opening and for closing the circuit, said actuating means including an operating handle, a member capable 0i' being set in motion by said operating handle to cause said cir- -5 cuit interrupter to move to the open and to closed circuit position, lost motion means intermediate said operating handle and said movab'e member, which allows said movable member, when it has been moved a predetermined distance, during the circuit closing operation by said operating handle, to disengage said operating handle and to move automatically to the closed circuit position, independently of said operating handle, and electro-responsive means for causing automatic opening of said interrupter upon the occurence of predetermined conditions, said lost motion means including means movable during the circuit closing operation to increase the amount of possible relative movement between said operating han- 20 dle and said movable member to a position where said electro-responsive means is capable of causing automatic opening of said interrupter irrespective of the position of said operating handle.

9. In a circuit interrupter, means for opening 25 and for closing the circuit, and actuating means therefor including an electro-responsive means, a pivoted actuating member, an over-center spring for connecting said actuating member with said means for opening and for closing the circuit, and an operating handle to permit manual operation of said interrupter, said electro-responsive means being actuable upon the occurrence of predetermined electrical conditions to cause sufficient relative motion between the line of action 35 of said spring and the pivot point of said actuating member to cause said spring to move said means for opening and for closing the circuit to the open circuit position, said operating handle having means associated therewith for releasably 40 engaging said actuating member during the circuit closing operation, said releasable engaging means permitting said electro-responsive means to cause said means for opening and for closing the circuit to move to the open circuit position 45 irrespective of the position of said operating handle.

10. In a circuit interrupter, means for opening and for closing the circuit, and actuating means therefor including an electro-responsive 50 means, a pivoted actuating member, an over-center spring for connecting said actuating member and said electro-responsive member, and an operating handle for permitting manual operation of said interrupter, said electro-responsive means 55 being actuable upon the occurrence of predetermined electrical conditions to cause suflcient relative motion between the line of action oi.' said spring and the pivot point of said actuating member to cause said spring to move said means for opening and for closing the circuit to the open circuit position, said operating handle having cam means associated therewith for releasably engaging said actuating member during the circuit closing operation, said releasable cam engaging 65 means operatively engaging said actuating member when said interrupter is in the open circuit position, so as to permit manual closing of said means for opening and for closing the circuit, and disengaging said actuating member when said ln- 70 terrupter is in the closed circuit position so as to permit said electro responsive means to cause said means for opening and for closing the circuit to move to the open circuit position irrespective of the position of said operating handle.

11. In a circuit interrupter, a pair ofsubstantially parallel switch arms, each movable to an open circuit and to a closed circuit position, and actuating means for moving said switch arms to the open and to the closed circuit position, said actuating means including means disposed in the space between said parallel switch arms for supporting said switch arms and a pivoted actuating member positioned for movement in the space between said parallel switch arms.

12. In a circuit interrupter, a pair of substantially parallel switch arms, and actuating means for moving said switch-arms to the open and to the closed circuit position, said actuating means including a frame member upon which said switch arms are supported and an actuating member pivotally supported on said frame member, said frame member being disposed in the space between said parallel switch arms, said actuating member moving in the space between said parallel switch arms during the operation of said interrupter.

13. In'a circuit interrupter, means, including a pair of substantially parallel switch arms for opening vand for closing the electrical circuit through said interrupter, and actuating means therefor including a frame member upon which said switch arms are supported, a pivoted actuating member, and an over-center spring for operatively connecting said actuating member and said means for opening and for closing the circuit, said actuating member and said over-center spring being positioned to move in the space between said parallel switch arms.

14.` In a circuit interrupter, means including a switch member, for opening and for closing the circuit, and actuating means therefor including an actuating member, an operating member, and a frame member, said operating member and said actuating member being pivotally supported on a common pivot means on said frame member, said switch member being likewise pivotally supported on said frame member but at a point spaced from said common point.

15. In a circuit interrupter, means for opening and for closing the circuit, and actuating means therefor including an actuating member, an operating handle, and an electro-responsive means, said operating handle engaging said actuating member through a lost motion connection comprising means defining a substantially nxed surface and movable means for defining another surface some distance from said first surface, said movable means causing an increase in the separation of said surfaces when said interrupter is in the closed circuit position, as compared with the separation when said interrupter is in the open circuit position, thereby making it possible for said electro-responsive means to cause said means for opening and for closing the circuit to move to the open circuit position independently of the position of said operating handle.

16. In a circuit interrupter, means for opening and for closing the circuit, and actuating means therefor including an actuating member, an operating handle, and an electro-responsive means, said operating handle engaging said actuating member through a lost motion connection comprising means defining a substantially xed surface and cam means for defining another surface some distance from said nxed surface, `said cam means causing an increase in the separation of 10 said surfaces when said interrupter is in the` closed circuit position, as compared with the separation when said interrupter is in the open circuit position, thereby making it possible for 'said electro-responsive means to cause said means 15 for opening and for closing the circuit to move to the open circuit position independently of the position of said operating handle.

17. In a circuit interrupter, means for opening and for closing the electrical circuit through said interrupter, and actuating means for said means for opening and for closing the circuit, said actuating means including an electro-responsive means, an actuating member which operatively engages said means for opening and for closing the circuit and which is movable between two extreme positions to cause said means for opening and for closing the circuit to move to the open and to the closed circuit position, and an operating member for moving said actuating member from one position to the other, said operating member having means for engaging said actuating member during the circuit closing operation so as to-permit a predetermined amount of relative movement between said operating member and said actuating member, said engaging means being movable during the nal stages of each circuit closing operation to increase the amount of possible relative movement between said operating member and said actuating member, the 4o said increase in possible movement making it possible for said electro-responsive means to cause said means for opening and for closing the circuit to move to the open circuit position irrespective of the position of said operating member.

18. In a circuit interrupter, a U-shaped frame member, means, including a switch arm pivotally supported upon said frame externally of the space enclosed by the two sides of said U, for opening and for closing the electrical circuit through said interrupter, a U shaped actuating member pivotally supported on said frame for movement within the space enclosed by the two sides of said frame, and a spring means for operatively connecting said switch arm and said actuating member, said spring means also being positioned to move within the space enclosed by the sides of said U shaped frame during the operation of said interrupter. o0

. OLIVER S. JENNINGS.

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