US2083305A

US2083305A - Circuit interrupter

Info

Publication number: US2083305A
Application number: US637749A
Authority: US
Inventors: Harry J Lingal
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1932-10-14
Filing date: 1932-10-14
Publication date: 1937-06-08
Anticipated expiration: 1954-06-08

Description

June 8, 1937. H. 1. LINGAL CIRCUIT INTERRUPTER Filed oct. 14, 1932 4 Sheets-Sheet l M www mL MJ w f d H WITNESSES:

',.TTORNEY June 8, 1937. H. J. LINGAL 2,083,305

CIRCUIT INTERRUPTER Filed Oct. `14, 1932 4 Sheets-Sheet 2 June 8, 1937.

H. J. LINGAL 2,083,305

CIRCUIT INTERRUPTER Filed oct. 14, 1932 4 sheets-sheet 3 |NvENToR HNyJLZ/vgaf.

'ATTRNEY June 8, 1937. H. .1. LINGAL CIRCUIT INTERRUTER Filed Oct. 14, 1932 4 Shees-Sheei'I 4 NVENTOR Har/"g L 277962Z.

ATTORN WITNESSE Patented June 8, 1937 CIRCUIT INTERRUPTER Harry J. Lingal, Wilkinsburg, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of.

Pennsylvania Application October 14, 1932, Serial No. 637,749

17 Claims.

My invention relates particularly to circuit breakers for use in controlling lighting and distribution network systems. Circuit breakers of this type are often placed in panelboards or in other enclosures of limited size, and it is necessary, therefore, that their over-all dimensions be reduced to a minimum. Particularly must the thickness be limited, since the standard panelboard will admit a breaker only 41/2 thick. Despite the space limitations, it is necessary that breakers of this type be capable of interrupting very large currents at moderately high voltages.

One object of my invention, therefore, is to provide an improved high-capacity circuit breaker that may be used in panelboards or in other enclosures of limited size.

Another object of my invention is tprovide an improved circuit breaker that is manually actu-rv able to open or close the circuit and is automatically actuable to open the circuit and to prevent the holding of the circuit closed during the occurrence of short circuit or overload conditions.

Another object of my invention is to provide an improved operating mechanism for breakers of this type which will permit the use of heavy contact parts and large capacity shunts, and at the same time, will be capable of opening and closing the circuit with a snap action.

Another object of my invention is to provide an improved toggle mechanism for opening and closing circuit breaker contacts that shall occupy a minimum of space and that shall use the space occupied with maximum efficiency.

A further object of my invention is to provide an improved tripping arrangement for circuit breaker operating mechanisms which utilize very powerful operating springs; my improved trip means to constitute a system of levers of large mechanical advantage having low friction and small inertia resistance, and being resettable by the operating handle of the breaker.

A still further object of my invention is to pro- Vide a new and improved contact structure for multi-pole circuit breakers in which the moving 'f' contact members are tied together by a bar tie and moved to the opened or closed position simultaneously by a single mechanism, the individual contact assemblages for the several poles to have separate means for supplying contact pressure for the individual poles.

As mentioned before, the principal field for immediate application of my invention is in connection with multi-pole circuit breakers for controlling lighting and distribution feeder circuits,

and I shall hereinafter describe an embodiment of my invention as applied to such circuit breakers, without in any way intending to restrict the scope of my invention except as indicated in the appended claims.

In this embodiment of my invention, I provide a plurality of switch members and a plurality of cooperating stationary contact members for opening a plurality of poles. In addition, I provide a manually operable mech'anism for opening 10 and closing the breaker contacts with a snap action, an insulating base upon which the structure is assembled, an arc extinguishing device for each pole, a spring for biasing each of the switch members to the open position, a releasable restraining means for holding all, of the switch members closed, and a unitary trip device for releasing the restraining means in response to a predetermined electrical condition in any one pole, and thereby opening all of the poles of the breaker; the releasing means being operable to `open the breaker regardlessof the position of the operating handle.

The features of my invention which I believe to be new are particularly pointed out in the appended claims. For a fuller understanding of the principles of the invention reference may be had to the accompanying drawings, in which:

Figure 1 is a plan View of a three-pole circuit breaker embodying the principalvelements of my invention; the cover has been removed to more completely show the various parts of the breaker structure.

Fig. 2 isa sectional view on the line II-II of Fig. 1, certain of the parts as shown in elevation to more clearly illustrate the structural features involved.

Fig. 3 is an enlarged fragmentary view showing the circuit breaker mechanism and the contact structure in the fully closed position. 4,0

Fig. 4 is an enlarged fragmentary view similar to Fig. 3 showing the circuit breaker mechanism and the contact structure in the opened position.

Fig. 5 is an enlarged fragmentary View similar to Fig. 3 showing the circuit breaker mechanism 45 and the contact structure in the tripped position. Certain of the parts have been cut away in Figs. 3, 4, and 5 in order to more clearly illustrate the disposition of the various elements of the mechanism and the contact structure.

Fig. 6 is a perspective view showing the circuit breaker operating mechanism and part of the contact structure.

Fig. 7 is a fragmentary perspective-view show- 55 ing the engaging portions of the carrier lever and the latching lever.

Fig: 8 is a fragmentary perspective view showing the central pole contact assemblage and a portion of the tie-bar used for interconnecting the contact structures of the several poles.

Fig. 9 is a perspective view of the circuit breaker operating member.

Fig. 10 is a perspective View showing the tog- 10 gle link and spring assemblage, and

, Fig. 11 is a fragmentary perspective view somewhat similar to Fig. 6 showing a part of the circuit breaker operating mechanism.

Referring to the drawings, the base I is of 15 molded insulating material and has mounted thereon terminal contacts 3 and 5, the unitary trip device 1, the circuit breaker operating mechanism 9 which has associated therewith the `assemblage of switch members Il. the arc extinguishers I3, and the stationary contact assemblage l5 of the switch members. The assemblage of switch members II and the stationary contact assemblages I5 combine to form the plurality of poles. Each of the poles is insulated from the adjacent pole by means of insulating barriers I I (Fig. 1 and Fig. 2) which are molded into the base I. These insulating barriers I1 aline with similarly shaped barriers 2| (Fig. 2) in the cover I9 which is likewise of insulating material. The operating member 23 has a handle 25 and is rigidly pivoted to the frame of the operating mechanism 9. The handle 25 is adapted to releasably engage the socket 26 in the operating member 23 in order that it may be removed to permit the closing of the door of the panelboard or other enclosure wherein the breaker is being used. An

opening 21 is provided in the cover I9 to accommodate the operating handle. The unitary trip device I is retained in position by the screw fastenings 3I and 33 which also serve to electrically connect the

terminals

35 and 31 of the trip device with the shunts 39 and the terminal contacts 5, respectively.

The electrical circuit for each of the poles is substantially the same. Beginning with the terminal contact 3, the current passes successively along the arc extinguishing structure I3, thence through the main stationary contact I6, the cooperating main moving contact I8 and the flexi- UO ble conducting shunt 39 which is associated with each of the switch,members, the terminal 35 of the unitary trip structure l, and finally through the trip structure to the other terminal contact 5.

The assemblage of switch members II is pivoted to the frame 4I of the operating mechanism 9 by means of a pin 42. A tie-bar 43 serves to rigidly interconnect the three switch members II-there being only one pivot point. As shown particularly in Fig. 8, each of the switch members II includes a clamp member for engaging the steel tie-bar 43, the bolts 4'I being provided as a fastening means. A square tube 48 of insulating material is positioned between the tie-bar 43 and the clamp members 45 to prevent the short circuiting of'the several poles.

Pivoted to each of the clamp members 45 4through the agency of the pin 49 are three main moving contact members I8; the central one of which has a projecting auxiliary contact member 5I which is used for engaging the stationary arcing contact 53. Springs are provided for biasing each of the main moving contact members I8 toward the cooperating main stationary 75 contact members I6 with a predetermined normal force. The end of the shunt 3S adjacent the switch members II is split into three sections (Fig. 8). One of these sections is ailixed to each of the pivotally mounted main contact members I8 through the agency of rivets 51. Each of the main moving contact members I8 has a rearwardly'extending portion 59 for engaging the end of the shunt 39.

The shunts 39 for the two outer poles are rigidly ailixed to the base I by means of the screw fastenings 6I and 64 which pass through suitable openings in the shunts. The shunt 39 for the central pole is held in place by four screws 62 which engage threaded openings in the base 4I of the operating mechanism. All oi the shunts 39 are of laminated construction, being built up from a plurality of thin sheets of copper, and are, therefore, longitudinally flexible.

The clamp member 45 of the central switch member II has a bifurcated section 65 formed integral therewith. This section 65 has openings 66 for engaging the contact assemblage pivot pin 42, openings 61 for engaging the breaker operating mechanism, and slotted openings 69 for clearing the pivot pin 'I5 of the operating member 23.

The limit of upward motion of the assemblage of switch members II is defined by the engagement of the portion 58 of the central clamping member 45 with the portions 'I2 of the U-shaped frame 4I. (See Figs. 4 and 5.)

The main stationary contact members I6 and the main moving contact members I8 have engaging faces 'I0 and 1I, respectively, which are composed of silver in order to improve the current-carrying qualities. The auxiliary stationary contact 53 and the engaging portion 54 of the auxiliary contact member 5I are composed of an arc-resisting alloy of tungsten and silver, the proportions being 60% of the former and 40% of the latter. I prefer to use arc resisting material for these contact surfaces in order to reduce to a minimum the injurious effects of the arc which is established therebetween during the operation of the breaker.

The arc extinguishers I3 which I prefer to use with my invention are of the spaced-plate type in which a plurality of composite plates having an edge portion of magnetic material and a central portion of non-magnetic material are 'i same outline as the moving contacts. and upon the establishment of the arc, due to the altering of the magnetic field adjacent to the arc path, force the arc to move into the spaces between the plates where it is rotated by suitable means associated with the extinguisher until it is cooled and extinguished. Patent No. 1,896,764, which was issued to M. W. Brainard on February 7, 1933,. and which is assigned to the assignee of this invention, fully discloses the structural features and fully describes the operation of an arc extinguisher of this type. Each of the arc extinguishers I3 is separated from the adjacentarc extinguisher by the insulating barriers II and Cil 2l; this construction gives an increased margin of safety while interrupting heavy current arcs by reducing the possibility of flash-over between adjacent poles.

'I'he operating mechanism 9 comprises, in general. a U-shaped base or frame 4I, a pair of toggle links 11 and 19 having one end connected to theassemblage of switch members through the bifurcated section 65, a carrier lever 8| for releasably restraining the other end of the toggle links 11 and 19 in an operative position, a channel shaped operating member 23, an over center spring unit 83 for connecting the operating member 23 to the knee of the toggle links, and the operating handle 25.

As previously mentioned, the U-shaped base 4| is positioned above the conducting shunt 39 of the central pole and is rigidly affixed to the base I by means of the screws 62; the operating mechanism 9` is thus electrically connected to the circuit of the central pole of the breaker, the reason for this will be brought out in a subsequent paragraph.

As previously pointed out, the assemblage of the switch members is pivoted 4to the base 4| by means of the pivot pin 42, and the channel shaped operating member 23 is pivoted to the base 4| by means of the pivot pin 15. The toggle link 11 comprises a ypair of substantially parallel links which are joined by a bridge portion 81 formed integral therewith. One end of the toggle link 11 engages the bifurcated section 65 of the central clamping member 45 through the agency of the pin 89 which pivots in hole 01.

The other end of the double toggle link 11 is pivoted to one end of the toggle link 19 by means of the knee pin 9|. The toggle link 19 comprises a pair of link sections joined by a bridge portion 93, similar to the bridge portion 81 joining the link sections of the toggle 11 but disposed Aat the extreme end of the links beyond the pin 9|. The bridge portion 93 is adapted to engage the bridge portion 81 of the link 11 When the breaker is in the fully closed position (Fig. 3) and provides a stop for defining the limit of upward movement of the knee of the toggle.

The over-center spring unit 83 operatively connects the end 95 of the operating member 23 with the knee pivot pin 9| of the toggle links and exerts a tension force therebetween. The spring unit 83 comprises a frame 96, one end of which is adapted to engage the knee pivot pin 9| and the other end of which has a circular opening to admit the plunger member 91. The over-center spring 98 which is itself in compression is positioned between the end 94 (Fig. 10) of the frame 96 and the enlarged portion 99 of the plunger. The other end of the plunger 91 pivotally engages the end of the operating member 23 by means of a pin |0| which lts into suitable recesses |02 (Fig. 9) in the member 23.

The end |03 of each of the parallel sections of the toggle link 19 is provided with a circular bearing portion |04. Each of these bearing portions |04 engages a suitable recess in the end of one of the parallel sections of the bell crank carrier lever 8|. Two retaining plates |05 (Figs. 6 and l1) are disposed on the outer sides of the carrier lever 8| to prevent the bearing portions |04 from moving sideways and disengaging the recesses.

The carrier lever 8| comprises a pair of parallel bell crank levers which are joined by a bridging portion |01 (Fig. 1). The` carrier is pivoted to the base 4| at the apex of the bell crank levers by means of a pin |09. The otherportions ||0 of the carrier lever 8| extend along the base 4| to form what might be termed a tail portion. The perpendicular distance from the center of the carrier pin |09 to the line of action of the toggle lever 19 is considerably less than the distance from the center point of the carrier pivot pin |09 to the bridging portion |01 which joins the tail portions ||0. This gives the carrier lever a very appreciable mechanical advantage over the toggle.

The over-center spring unit 83 at all times exterts a force on the carrier lever 8| biasing that lever in a clockwise direction- (Figs. 3, 4 and 5) and it is to restrain the carrier lever 8| in the operative position that the latching lever is provided.

Similar to the other parts of the operating mechanism 9 the latching lever comprises a pair of parallel sections which are joined by bridging portions ||2 and ||3. One end of the latching lever is pivoted to the base 4| by the pivot pin ||5 adjacent the point of engagement with the tail piece ||0 of the carrier member 8|. hangs the bridge portion |01 which connects the tail members ||0 of the carrier lever 8| and thus holds the carrier lever 8| in an operative position by preventing it from moving upward. The free end of the latching lever is releasably restrained by means associated with the trip device 1, the releasable restraining means engaging the projection ||1 on the bridging portion ||3 (Fig. 11).

It should be noted at this point that the mechanical advantage of the latching lever is very great with respect to the carrier lever 8|; the distance from the center of the latching lever pivot pin ||5 to the point of engagement of the bridging members ||2 and |01 (that is, the point of engagement of the latching lever and the carrier lever) is very small as compared with the distance from the center of the pin ||5 to the point of engagement of the trip device 1 and the latching lever Furthermore, it should be noted that the various parts of the frame 4|, the carrier lever 8|, and the latching lever are all disposed to occupy a minimum of space upward from the base; they are all arranged substantially parallel to each other and all extend along the base, both of these characteristics being 'of great value in securing a mechanism which occupies a minimum of space, but which is capable of satisfactory operation with large sized mechanical parts and heavy operating springs.

My invention is not particularly concerned with the trip device 1, and any releasable restraining means capable of releasing the unpivoted end of the latching lever in response to a predetermined electrical condition may be used. I prefer to use a trip device similar `to that disclosed in my copending application, which issued July 14, 1936, as Patent No. 2,047,739, and which is also assigned to the assignee of this invention. This trip device has a thermally responsive and a magnetically responsive element electrically connected in each pole `of the breaker. A com, mon trip bar which is actuable by any one of the thermally responsive or magnetically responsive tripping elements engages the circuit breaker operating mechanism through suitable linkages. Upon the occurrence of an overload in any one of the poles, the thermally responsive element acts to trip all of the poles of the breaker after a predetermined interval. Upon the occurrence of a short-circuit condition in any one of the poles of the breaker, the magnetically responsive element in that pole is immediately energized and likewise opens all of the poles of the breaker. Suitable means are provided for returning al1 The bridge portion ||2 normally over-A ci the parts of the trip device to an operative condition, following each operation thereofthe trip device is thus completely automatically resettable.

The operation of this embodiment of my invention may best be described in conjunction with Figs. 3, 4, and 5 which show the disposition of the various parts of the mechanism for the three static positions of the breaker contacts.

Fig. 4 shows the circuit breaker contacts in the fully opened position with the mechanism in the operative or set condition; thatv is, the tail portion of the carrier lever 8| is held in position along the base by the overhanging bridge portion ||2 of the latching lever |I|, and the latching lever I I, in turn, is releasably restrained' in position along the base by the linkage ||8 which operatively connects the projection ||1 on the latch lever I with the mechanism of the trip device 1. It will be noted that the knee pivot pin 9| 4is positioned adjacent the base I, and the operating spring unit 83 extends along, and is substantially parallel to, the base I. The operating spring unit 83 has drawn the operating member 23 clockwise about its pivot pin 15 until the two rollers ||9, disposed on opposite sides of the channel shaped operating member 23, have engaged the surfaces |2| (Fig. 6) on the two parallel bell crank lever units of the carrier lever 8|. This engagement of the rollers I|9 with the carrier member 8| provides a convenient and satisfactory means for defining the limit of motion of the operating member 23 in a clockwise direction; these rollers ||8 also provide a I means for resetting the carrier and latching levers following the opening of thebreaker by the trip device, as will be explained in some detail later. "i

To close the breaker, the operating handle 2 5 is moved in a. counter-clockwise direction (Fig. 4) about its pivot pin 15;. the pin which connects the operating spring unit 83 with the operating member 23 is likewise moved in a counter-clockwise direction about the pivot pin 15, and as soon as the line of action of the spring unit has moved over the center line of the link 19 the operating spring unit 83 exerts a force having a component biasing the knee pivot pin 9| upwardly from the base. This component increases as the operating handle is moved toward the closed position and reaches a suilicient magni- `tude to set the knee of the toggle in motion.

, member and the frame member 4I.

Once the mechanism is set in motion the closing operation proceeds rapidly and more or less automatically because any upward movement of the knee pivot pin 9| progressively increases the effective force component of the operating spring unit 83, and the knee pivot pin is therefore continuously accelerated upward and the contacts move to the closed position (Fig. 3) with a snap action.

With the contacts in the closed position, (Fig. 3), it will be noted that the center line of the toggle links is substantially parallel to the base In addition, the line of action of the force exerted by the operating spring unit 83 on the operating member 23 is such as to bias that member counter-clockwise about its pivot 15. The limit of this counter-clockwise movement of the operating member 23 is defined by the oir-set projections |23 on the frame 4| which engage suitable protuberances |24 on the operating member 23.

To open the circuit breaker contacts manually,

the operating handle 25 (Fig. 3) is moved in a clockwise direction about the pivot pin 15 of the operating member 23. This moves the operating spring unit 83 over center to a position where it exerts a component of force tending to move the knee of the toggle toward the base. The movement of the various parts of the operating mechanism is* now automatic and the contacts are opened with a snap action; the various parts returning to the position shown in Fig. 4.

During the opening and closing operations of the breaker, the circuit is first established and finally interrupted through the auxiliary contacts 5| and 53, although, as pointed out before, the auxiliary contacts are open when the main contacts are in the fully engaged position.

The operating mechanism, when in the fully closed position (Fig. 3) is substantially locked in. This results from the fact that the operating member 23 is biased counter-clockwise by the operating spring unit 83 into engagement with the frame 4|, the line of action of the spring unit being above (Fig. 3) the pin 15. Furthermore, there isa slight clearance between the bridging member' 81 on the toggle link 11 and the projections 88 on the bifurcated section 65 of the central clamping member 45, which permits the bridge membe'r 93 oi the toggle link 19 to abut against the bridge member 81. Thus, since the carrier member 8| is rigidly restrained in position by the engagement of its tail piece I I0 with the latching lever the entire assemblage of movable parts is rigidly interconnected to lock the contacts in the engaged position. This locking or holding of the contact members is of great assistance in maintaining uniform contact pressure and in preventing any burning ofthe engaging contact surfaces, because, to be effective, the contact springs 55 must exert a substantially constant force biasing the engaging contact surfaces together.

The trip device 1 operatively engages the circuit breaker mechanism 9 through the agency of the trip lever ||8. This lever II8 comprises a pair of parallel sections joined by two pins |24a and |26, and is pivotaily supported within the trip structure.- The pin |2411 is adapted to overhang the projection ||1 on the free end of the latching leverfIIi and thus relcasably restrain the mechanism 9 in the operative position. Both the spring |21, oneend of which engages a suitable recess in the bridging member ||2, and the operating spring unit 83 exert a force biasing the projection I1 upwardly (Figs. 3 and 4) against the pin I24a or more explicitly bias the mechanism to the inoperative position. These forces are, however, reduced to a very small magnitude by the large mechanical advantage of the latching and carrier levers, and the restraining force which must be exerted by the lever ||8 is sui`- ilciently small to permit a very sensitive trip device. The pin |28 is used during the resetting operation to restore the trip lever |I8 to the iatchecl position.

When the breaker contacts are in the fully closed position (Fig. 3) and an over-load or short-c|rcuit condition occurs in the circuit controlled by any one oi' the poles of the breaker, the lever |I8, which is normally held in the position shown in Fig. 3 is released by the trip mechanism and immediately moves so that the pin |24a uncovers the projection ||1 on the latching lever III. The latching lever then moves counter-clockwise about its pivot ||5 assemblage of switch members in a clockwise direction (Fig. 3) about their pivot point, the pin 42, the clearance between the projections 88 vand the bridge portion 81 is taken up, and the link 11 is likewise caused to move clockwise about the pin 42. This movement of the link 11 moves the knee l pivot pin 9| downwardly and at the same time causes the carrier 8| to move clockwise about its pivot point |09. The resultant effect of these movements is to cause the toggle to collapse downwardly under the combined forces of the contact springs 55 and the operating spring unit 83. 'Ihe various parts of the mechanism then move to the position shown in Fig. 5. As in the case of manual operation, the contacts are opened with a snap action due. to the progressive acceleration vof the moving parts as the toggle collapses. During the opening operation the line of action of the operating spring unit 83 moves from a position above the center of the pivot pin 15 for the operating member 23 to a position below the center of the pin 15. The operating member is then biased clockwise about the pin 15, and moves to a position approximately midway between the open and closed positions, the clockwise movement of the operating member 23 being limited by the engagement of the rollers ||9 with the surfaces 2| on the carrier member 8|. This positioning of the operating handle provides a ready indicating means for showing when the breaker has been opened by the action of the trip device rather than manually.

Following each opening operation of the circuit breaker in response to overload or shortcircuit condition, it is necessary to restore the circuit breaker operating mechanism and the trip device to an operative condition. This is done by moving the operating handle to the normal open position for manual operation. As the` operating handle 25 and the connected operating member 23 are moved clockwise from the position shown in Fig. 5, the rollers ||9eengage the surfaces |2| of the carrier member 8| and move the member counter-clockwise about the pivot |89. As shown particularly in Fig. '1, the. bridging portion |81 which connects the two tail portions il of the carrier lever 8| has a recess |29 therein which is adapted to engage a projection |3| forming a part of the bridging portion ||2 which connects the two side portions of the latching lever This engagement of the bridging portion |81 and the projection |3| causes the counter-clockwise movement of the carrier lever 8| to be transmitted to the latching lever As a result, the latching lever is r moved clockwise against its biasing spring |21, and when the operating member 23 has nearly reached its limit of travel in a clockwise direction, the carrier lever 8| and the latching lever have been restored to the position shown in Fig. 4.

The pin |28 of the trip lever 8 is adapted to be engaged by the projection i1 on the latching lever during the resetting operation. Thus, when the clockwise movement of the operating member 23 is stopped, the bridging portion |01 The conhas been moved underneath the bridging portion ||2, the projection I |1 of the latching lever |1|| has been reengaged by the pins |24a of the trip lever IIB and the carrier lever 8| has been completely restored to the operative position. The breaker may then be opened and closed manually as described in a previous paragraph.

Should an attempt be made to close the breaker against an overload or against a short circuit condition, the latching lever will be released after a predetermined time delay, or instantaneously, depending upon the magnitude of overload, exactly as described before. The carrier lever will likewise be released and will cause the toggle mechanism to break so as to open the circuit breaker contacts independently of the position of the operating handle. Thus, it is not possible to hold the breaker closed against a short circuit or against a continued overload condition.

For the most satisfactory operation of the arc extinguishers* I3, it is necessary that the top plate of each of the arc extinguishers be connected to the moving contact members at all times. This is accomplished in the two outer poles of the breaker by means of a copper strap |33 (see Fig. l) which is fastened at one end to the top plate of the arc extinguisher |3 and at the other end to the shunt 39. The top plate of the central arc extinguisher is electrically connected to the frame 4| of the operating mechanism 9 through a pair of straps |35 (Figs. 1 and 2); the frame 4| being electrically connected to the central shunt 39 as mentioned before.

It will be seen that have disclosed a new A improved circuit' interrupter which possesses a number of novel and advantageous features. By

my improved toggle operating mechanism which positions the toggle links substantially parallel to the base member and in a plane substantially normal to the path of movement of the separable contact members, I have made possible a great saving of space, particularly of thickness. In addition to this I have provided my improved toggle operating mechanism with stops integral with the toggle links themselves, and a new carrier and carrier-restraining system whereby very powerful over-center springs may be used for the actuation oi' the toggle 4and which, at the same time, permit the use of very sensitive trip devices.

While in accordance with the patent statutes I have given the foregoing details of a practical embodiment of my invention, it is to be understood that many of these are merely illustrative and that variations in their precise form will be desirable in some applications. I desire, therefore, that the language of the accompanying claims be accorded the broadest reasonable construction and that my invention be limited only by what is explicitly stated in the claims and by the prior art.

I claim as my invention:

l. In a circuit interrupter, a movable switch member for openingand closing the circuit, and an operating mechanism for said switch member including a pair of toggle links, an operating member, an overcenter spring for operatively connecting the knee of said toggle with said operating member, and a releasable trigger means for said toggle links movable to open the circuit, in response to a predetermined electrical condition, independent of the position of said operating member, said releasable trigger m'eans including a pair of pivoted levers each of large mechanical advantage.

fil

2. In a circuit interrupter, means including a pair of relatively movable contact members for opening and closing the circuit upon which the several structural elements of said interrupter are mounted, j a base member, and operating mechanism for said movable contact members including a toggle linkage, formed by a pair of toggle links, a carrier means for movably supporting one end of said toggle linkage, an operating member, and an overcenter spring for operatively connecting the knee of said toggle linkage with said operating member, said toggle linkage being collapsed When said interrupter is in the open circuit position and being extended when said interrupter is in the closed circuit position, and the center line of said toggle linkage, when said interrupter is in the closed position, being disposed in a plane substantially normal to the path of movement of said relatively movable contact members, the knee of said toggle moving toward said base when said relatively movable contact members move to the open position.

3. In a circuit interrupter, means including a pair of relatively movable contact members for opening and closing the electrical circuit through said interrupter, a substantially fiat base member upon which the several structural elements of said interrupter are mounted, and operating mechanism for said contact members including a toggle linkage formed by a pair of toggle links, a carrier means comprising a releasable bell crank lever pivoted adjacent said base for engaging and supporting one end of said toggle linkage, an operating member also pivoted adjacent said base, and an overcenter spring for operatively connecting the knee of said toggle linkage with said pivoted operating member, the line of action of the force exerted by said operating mechanism when moving said relatively movable contact members to the open and to the closed position being substantially parallel to the plane of said base, said pivotally mounted'bell crank having a portion extending upwardly from said base for engaging said toggle and a tail portion extending along and substantially parallel to said base when the relatively movable contacts are in the closed position, the center line of the toggle links, when said interrupter is in the closed position, being disposed in a plane substantially normal to the path of movement of said relatively movable contact members, the knee of `said toggle linkage and the free end of said operating member moving toward said base when said relatively movable contact members move to the open position, the tail of said carrier being biased away from. said` base by said overcenter spring.

4. In a circuit breaker operating mechanism, a base member, a contactv assemblage pivotally supported on said base and movable to open or close the circuit, a carrier lever, a toggle linkage comprising a pair of interconnected toggle links for actuating said `contact assemblage, 4said linkage being pivoted at one end to said Contact assemblage and at the other end to one end of said carrier lever, an operating member pivotally supported on said base, an overcenter spring connecting the knee of said toggle linkage with said operating member, and a latching lever likewise pivotally supported on said base, said carrier lever being pivotally supported on said base intermediate its ends and having a tail portion extending along said base to engage said latching lever, said latching lever being supported on said base adjacent the point at which it engages said tail portion so as to possess a large mechanical advantage over said carrier lever and thereby be capable of controlling said carrier lever by the exertion of a very small force.

5. In a circuit interrupter, a base member, a movable switch member for opening and closing the circuit, and an operating mechanism for said switch member, including a pair of toggle links, an operating member, a spring for operatively1 connecting the knee of said toggle with said operating member, and a releasable restraining means for supporting one end of said toggle in an operative position, the other end of said toggle being pivoted to said movable switch member, said releasable restraining means including a pair of engaging bell crank levers, and an electrically responsive trip device, each of said bell crank levers being pivoted adjacent said base and having a portion extending along said base, the point of engagement of said levers being adjacent one of the'pivot points thereof, and one arm of one of said levers being releasably restrained by said trip device.

6. In a circuit interrupter, a base member, a movable switch member for opening and closing the circuit and an operating mechanism for actuating said switch member including a pair of Ptoggle links pivotally fastened to each other at one -end to form the knee of the toggle, an operating member, and a releasable restraining means for supporting one end of said toggle links in an operative position, the other end of said toggle being pivoted to said movable switch member, said releasable restraining means including an electrically responsive trip device, a bell crank carrier lever for engaging said toggle, and a bell crank latching lever for engaging and operatively connecting said carrier lever and said trip device, both of said bell crank levers being pivoted adjacent said base and having one arm extending along said base, the point of engagement of said levers being adjacent one of the pivot points thereof, said carrier lever having an arm extending upwardly from said base to engage said toggle, and having means associated therewith for engaging said latching lever to reset the mechanism following the opening of the interrupter by said trip device.

7. In a circuit breaker operating mechanism, a base member, a contact assemblage pivoted adjacent said base and having movable contact 'f' members for opening and closing the circuit, a pair of toggle links pivoted at one end to said contact assemblage and at the other end to a releasable tripping means, an operating member pivoted adjacent to said base, and an overcenter spring connecting the knee of said toggle links with said operating member, the center line of 'said toggle links being in a plane substantially parallel to said base member and normal to the path of movement of said contact members.

8. In a circuit interrupter, a substantially iiat base having mounted thereon separable contacts and a pivoted member movable between two extreme positions for actuating said contacts, a spring the line of action of which is movable across the pivot point of said pivoted member for moving that member from one of said two positions tothe other with a snap action, the plane of movement of said spring and pivoted member being generally perpendicular to the plane of said base, and the line of action of said spring and the center line of said pivoted member being generally parallel to the plane oi said base at the time when said line of action moves across said pivot point.

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9. In a circuit interrupter, a substantially at base having mounted thereon separable contacts and a pivoted member movable between two extreme positions for actuating said contacts, a spring movable across the pivot point of said pivoted member for moving that member from one of said two positions to the other with a snap action, the plane of movement of said spring and pivoted member being generally perpendicular to the plane of said base, the center line of action of said spring and the center line of said pivoted member being generally parallel to the plane of said base at the time when said line of action moves across said pivot point, and an operating handle connected to move the line oi" action oi said spring across said pivot point, said handle being movable in a plane generally perpendicular to the plane of said base.

10. In a circuit interrupter, a pair of separable contacts, a movable carrier, a member for actuating said separable contacts pivoted on said carrier, a spring for actuating said movable m-ember, said carrier having a long arm having a latching portion at the end thereof, and a latching lever for engaging said latching portion, said latching lever having a long arm extending along and generally parallel to the long arm of said carrier when in the latched position.

11. In a circuit interrupter, separable contact means for opening and for closing the electrical circuit therethrough, and actuating means for said Contact means including an operating member movable between two extreme positions, means operable in response to-mo-vement of said operating member to open and to close said separable contact means, a member movable from a normal inoperative to an operative position to cause said mechanism to move said contact means automatically to the open circuit position, means biasing said member to said operative position, releasable means including a pair of coacting, pivoted levers, each of large mechanical advantage, for normally retaining said member in said inoperative position, and electro-responsive means operable to cause said means for retaining said member in said inoperative position to release that member and permit it to be moved to said operativaposition by said biasing means therefor.

12. In a circuit interrupter, separable contact means movable to an open and toa closed circuit position, and actuating means for said contact means including an operating member movable between two extreme positions, means operable in response to movement of said operating member lto move said separable contact means Vto saidy open and to said closed circuit position with a snap action, a trigger or cradle member movable `from a normal inoperative to an operative position to cause said mechanism tomove said contact means automatically to the open circuit position with a snap action, independently of the position of said operating member, means biasing said trigger or cradle member to said operative position, releasable latching means, which includes a pair of coacting, pivoted levers, each of large mechanical advantage, for normally retaining said trigger or cradle member. in said inoperative position, and electro-responsive means operable to cause said latching means to release the trigger or cradle member and permit that member to be moved to said operative position by said biasing means therefor.

13. In a circuit interrupter, separable contact means movable to an open and to a closed circuit position, and actuating means for said contact means including an operating member movable between an' open circuit and a closed circuit position, means including an over-center spring, one end of which is mechanically connected to said operating member, operable in response to movement of said operating member to move said sep-- arable contact means to said open and to said closed circuit position with a snap action, a trigger or cradle member movable from a normal inoperative to an operative position to cause said actuating means to move said contact means automatically to the open circuit position with a snap action, irrespective of the position of said operating member, means biasing said trigger or cradle member to said operative position, releasable latching means, which includes a pair of coacting, pivoted levers, each of large mechanical advantage, for normally retaining said trigger or cradle member in said inoperative position, and electro-responsive means operable to cause said latching means to release trigger or cradle member and permit that member to be moved to said operative position by said biasing means therefor.

14. In a circuit interrupter, means including a pair of relatively movable contact members for opening and closing the circuit, a base member upon which the severalstructural elements of said interrupter are mounted, and operating mechanism for said movable contact members including a toggle linkage formed by a pair of toggle links, an operating member, an Overcenter spring operatively connected between one of said toggle links and said operating member for moving said toggle linkage to both collapsed and extended positions with a snap action, said toggle linkage being collapsed when said interrupter is in the open circuit position and being .extended when said interrupter is in the closed circuit position, the center line of said toggle linkage, when said interrupter is in the closed circuit position, being substantially parallel to the base member and the knee of said toggle moving toward said base when said relatively movable contact members move to the open position.

15. In a circuit interrupter, a base member, a contact actuating member pivotally mounted on said base member at a point adjacent to the base member and having a portion extending outwardly from the base member", a contact movable between open and closed positions by said contact actuating member, a pair of toggle links pivoted at one end to said outwardly extending portion of the contact actuating member, said toggle links being movable from a collapsed to a more nearly straightened position to move the point on said outwardly extending portion of the contact actuating member to which they are pivoted in a direction generally parallel to the base member and move said contact member to closed position, an operating member, a spring operatively positioned between said operating member and said toggle links for moving said toggle links and saidcontact to both open and closed positions with a snap action, and a tripping member movable upon the occurrence of a predetermined condition in the circuit to collapse said toggle links and thereby move said contact member to open position.

16. In a circuit interrupter, a base member, a contact actuating member pivotally mounted on said base member at a point adjacent to the base member and having a portion extending outwardly from the base member in a direction generally perpendicular thereto, a contact movable between open and closed positions by said contact actuating member, a pair of toggle links pivoted at one end to said outwardly extending portion of the contact actuating member, said toggle links being movable from a collapsed to a more nearly straightened position to move the point on said outwardly extending portion of the contact actuating member to which they are pivoted in a direction generally parallel to the base member and move said contact member to closed position, an operating member, an overcenter springoper atively connected between said operating member and said toggle links for moving said toggle links and said contact to both open and closed positions with a snap action, and a tripping member movable upon the occurrence of a predetermined condition in the circuit to collapse said toggle links by moving the knee thereof toward said base member and thereby move said contact member to open position.

17. In a circuit interrupter, a base member, a fixed contact mounted thereon, a bell crank pivotally mounted at its apex adjacent to said base member, said bell crank having a movable contact resiliently mounted on one arm thereof extending generally parallel to the base for engaging said xed contact on the base, and the other arm of said bell crank extending outwardly from the base in a direction generally perpendicularly thereto, a pair of toggle links pivoted to said outwardly extending arm of the bell crank, said pair of toggle links being in a substantially straight .position generally parallel to said base to hold said movable contact in engagement with said fixed contact and the knee of said toggle links being movable toward said base to collapse the toggle and move said movable contact to open position, an operating member, a spring actuable by said operating member for moving said toggle links between collapsed and straightened positions with a snap action, and a tripping member movable upon the occurrence of a predetermined condition in the circuit to cause collapse of said toggle and movement of said movable lContact to open position irrespective of the position in which said operating member may be held.

HARRY J. LINGAL.