US2421830A - Multipole tripping device - Google Patents

Description

June 10, 1947. L. w. COLE El Al. 2,421,830

IULTIPOLE 'I'RIPPIiG DEVICE Filed Dec. 4, 1942 3 Sheets-Sheet 1 3nnentor$ 1 0 5 W- (6 4m,

THOMAS M. (045 PM; 0; adv

attorney June 10, (1947. L. w. COLE ET AL 2,421,330 v IULTIPOLE TRIPPING DEVICE Filed Dec. 4, 1942 s sheots sheet 2 Z'mventors LOUIS W- fulfi THOMA: 0.004:

June 10, 1947. L, w COLE r AL 2,421,830

IULTIPOLE TRIPPING DEVICE Filed Dec. 4, 1942 5 Sheets-Sheet 3 'IIIIIIIIII/l Sumter:

Lou: W- (In: An Tmmns (ou MAQL Patented June 10, 1947 UNITED STATES PATENT OFFICE MULTDOLE TRIPPIN G DEVICE Louis W. Coleand Thomas M. Cole, New York, N. Y., assignors to Cole Industries, Inc., Long Island City, N. Y., a corporation of New York Application December 4, 1942, Serial No. 467,842 (Cl. 200-116) 25 Claims.

This invention relates to trippin devices for multi-pole electric switches or circuit breakers for interrupting the circuit at all poles of the switch upon the occurrence of an overload in any one or all of the lines controlled by the switch. This invention relates also to multi-pole switches or circuit breakers provided with tripping devices.

This application is related to our application Ser. No. 410,144 filed September 9, 1941, which discloses a tripping device for operating a multipole switch whereby the latter is automatically opened simultaneously at the contacts of all the poles in case of overload in any one or more of the lines controlled by said switch. The apparatus of our present application comprises another embodiment of the invention disclosed and claimed in said prior application and includes additional features of construction and operation in respect to the tripping device and to the switch operable under the control of said tripping device.

Also, the apparatus of the present invention comprises a multi-pole switch in which the companion contacts at each pole are not only relatively movable but are also individually movable when the switch is tripped under the control of the tripping device.

The apparatus of the present invention embodying certain of the principles of the invention disclosed in our above mentioned prior application will be more fully understood from the following description, considered in connection with the accompanying illustrative drawings.

In the drawings:

Fig. l is a. top view of a multi-pole circuit breaker embodying the present invention, the casing cover being removed;

,Fig. 2 is a sectional view on the line 2-2 of Fig. 1;

Fig. 3 is a sectional view on the line 3-3 of Fig. 2, parts being omitted for the purpose of illustration;

Fig. 4 is a view in elevation 01' one end tripping device;

Fig. 5 is a sectional view of the tripping device on the line 5-5 of Fig. 4, parts being omitted for the purpose of illustration;

.Fig. 6 is a sectional view on the line 8-4 of Fig. 1; A

Fig. 7 is a perspective view 01' part of the tripping device;

Fig. 8 is a sectional view on the line 9-4 of Fig. 2, a part beingomitted for the sake of clearness of illustration;

Fig. 9 is a sectional view on the line 9-9 of F sv oi the Fig. 10 is a sectional view, on a larger seal on the line lO-lfl 01118.2;

Fig. 11 is a fragmentary sectional view similar to Fig. 2, parts omitted, illustrating the tripped condition of the switch;

Fig. 12 is a view similar to Fig. 11 illustrating the manual operation of the switch for opening the same and illustrating also the manner or resetting the switch;

Fig. 13 is a detail sectional view on the line l3ll of Fig. 11.

Referring now to the drawings in detail, the tripping device Ill embodying the present invention is mounted in a casing 12 for tripping a multi-pole switch ll. Casing I2 is preferably formed of insulation material, as here shown, but can be made wholly or partly of metal with suitable provision for necessary electrical insulation. Said tripping device is constructed and arranged in such manner that upon an occurrence of an overload in any one of the lines, switch H is opened simultaneously at the companion contacts at all of the poles thereof.

The tripping device In comprises a trip-releasing member l6 including, as here shown, an insulation plate l8 having fixed thereto a detent and resetting member 20. Member 20 is formed preferably in one piece of metal and is rigidly secured to plate It in any suitable way, for example, by fastening the lateral projections 22 of member 20 to said plate I8 by rivets 24. As illustrated in Fig. 2 the combined detent and reseting member 20 has an integral detent element 26 (see also Figs. 5 and 11) which releasably engages a proiectionpr trip-released element 28 of a metal plate' 30 forming part 01' a trip released member 32, for holding switch It in set condition, said switch being automatically opened or tripped when detent element 26 disengages projection 28 of the trip released member 32. Trip-releasing member I6 is mounted for movement from a projected position, in which it engages the trip-released member for holding the switch in set condition, to a retracted position, in which detent element 28 disengages the trip released member "for tripping the switch. Said trip-releasing member I6 is releasably held in said projected position by three current-responsive members, here shown as thermostats constituted by bimetallic thermostatic strips 34. More particularly, the displaceable ends 38 of strips 34 are, in the normal or set condition 01' the switch, in engagement with parts of trip-' releasing member l6, here shown as radially proiecting tongues 38 of brackets 40 which are rigidly fixed to plate l8. The opposite ends 42 of strips 34 are securely fixed to companion stationary terminal members 44, 48 and 48, respectively, hereinafter more specifically described. Thermostatic strips 34 are arranged so that the movable ends 36 thereof are in equi-spaced relation circumferentially of a circle, and brackets 48 are similarly disposed in equi-spaced circumferential relation. This circumferential relation is illustrated in Fig. 3 and also in Fig. 4. The movable ends 36 of strips 34 engage the companion tongues 38, respectively, of brackets 48 near the ends of said tongues. The detent element 26 is disposed at or in line with the center of said circle at the circumference of which the ends 36 of the bimetallic strips 34 engage the projections 38 in the projected position of trip released member l6.

The trip-releasing member 16 is mounted for said movement thereof on three supporting members, here shown as metal bars 58, which have end portions 52 secured to companion terminal members 44, 46 and 48 (Fig. 1) in any suitable way, for example by threading said end portions into openings in said terminal members. Said bars 58 are preferably 01' circular cross section and are slidably engaged by the reflexed end portions 56 of brackets 40, said bars extending through guide openings 58 in said end portions in alignment with openings 68 in plate H! which register with openings 62 in the end portions 64 of brackets 40, respectively (Fig. 4). Each bracket 40 is constituted by a one-piece U-shaped member, the tongue 38 being struck out from the intermediate part 65 of the bracket and bent up so that it lies in the plane of end portion 64 parallel to the plane of plate Hi. The three brackets are secured at the corner portions 61 of plate 18 by rivets 63 which fasten end portions 64 of the brackets to said plate.

Trip-releasing member 16 is held releasably in engagement with the ends 36 of bimetallic strips 34 by means here shown as springs 66 which also constitute means for biasing and for moving said trip-releasing member I6 to retracted position. Each spring 66 is a coiled compression spring which surrounds a companion bar 58 and bears at one end thereof against an end portion 56 of the companion bracket member 40 and at the opposite end thereof against an abutment 68 fixed to said bar 58. It will be understood that upon the occurrence of an overload in any line controlled by the switch, the corresponding bimetallic strip 34 will move outwardly of the adjacent edge of projection or tongue 38 with the result that the pressure of one or all of springs 66, as the case may be, will cause movement of trip-releasing member l6 to a retracted position, thus disengaging detent element 26 from projection 28 of trip-released member 32. In the event of an overload in only one line or in only two lines controlled by the switch, plate l8 when released by the bimetallic strip 34 of the line or lines in which the overload occurs will tilt toward the axis which passes through the center of the circle referred to above, and will cause detent element 26 to move sufllciently to disengage projection 28 of trip-released member 32, for tripping switch l4, even though the other bimetallic strips 34 remain in engagement with their companion tongues 38. This tilting movement is permitted by slots 58 which, as shown in Fig. 3, are large enough to provide a clearance between end portion 53 of the bracket and adjacent portions 16 of the companion bar 58. It will be observed, however, that the three bars 66 are so arranged and engage said end portions 66 of the bracket so as to prevent turning movement of plate is around the axis of the circle referred to, so that tongues 38 are at all times maintained in position for engagement with the ends 36 of the companion bimetallic strips 34, respectively, when the tripping device is reset. Bars 58 are preferably circular in cross section, but they can be non-circular. When all of the thermostatic strips 34 disengage the trip-releasing member [6, at tongues 38 thereof, said member i6 moves to a retracted position longitudinally of bars 58, It will be understood further that even if an overload occurs in only one or two of the lines, the disengagement of the corresponding thermostatic strips from member l8 may be sufllcient to result in the disengagement of the remaining strips when the movable ends of said strips are slightly rounded or are positioned at the very edges of tongues 38.

The tripping device 18 is preferably mounted as a unit in casing I2 of the circuit-breaker, and provision is made for removably securing said unit in said casing. The support for the unit comprises a base 12 of insulation material which is seated upon the raised transversely extending end portion 14 of the bottom wall of casing l2. Base 12 may be removably secured in position by any suitable means, here shown as screws 16, threaded through wall portion 14 and into base 12 (Figs. 1 and 6), said wall portion 14 having a transversely extending groove 18 through which said screws are entered and which reduces the thickness of wall portion 14. Base 12 is provided with laterally spaced upstanding partitions or barrier members 88 which are integral with or otherwise in fixed relation to said base. Terminal members 44, 46 and 48 are secured to the top of base 12 in any suitable way, here shown as by screws 82, which are fastened to the end portions 84 of said terminal members. Leadterminal connectors 86 for the three line terminals are electrically and mechanically connected individually to end portions 84 of said terminal members, respectively, by the screws 82 which secure the end portions 84 of said terminal members, respectively, to base 12.

Terminal members 44 and 48 have parts 88 and 38, respectively, which are disposed in vertical planes and to which the threaded end portions 52 of two or the bars 50 are securely fastened as hereinbefore indicated. The intermediate terminal member 46 is provided with a portion 32 to which the end portion 52 of the third bar is fixedly secured. The end terminal members 44 and 48 are provided at the ends of parts 88 and 38 thereof with forwardly reflexed portions 34 and 86, respectively (Figs. 1 and 6), and the intermediate terminal member 46 has a forwardly reflexed portion 38 (Figs. 5 and 6). The reflexed ends 42 of two of the bimetallic strips 34 are positioned and clamped between parts 88 and 38, respectively, of the companion terminal members and the adjacent surface portions of upstanding parts 83 of the base. Similarly, the reflexed end portion 42 of the third bimetallic strip 34 is positioned and clamped between vertical portion 32 of terminal member 46 and theadjacent surface portion of base 12.

Thermostatic strips 34 are additionally secured in position by means which also includes means for adjusting said strips for calibrating the tripping device. For this purpose, a collar I82 having an adjusting screw I84 is associated with each 01' said thermostatic strips, two of said collars being mounted on portions 34 and 33 of terminal members 44 and 48, respectively, and the third collar being mounted on portion 880i terminal member 45, The longitudinally extending portions of strips 34 are positioned between said portions 84, 95 and 88, respectively, of the companion terminal members and the confronting wall portion I05 oi the companion collar I02 (Figs. 1 and 5). The screw I04 which is in threaded engagement with wall I05 oi the collar not only engages the companion bimetallic strip 34 for adjusting the position of the end 35 of said strip in relation to the end of the companion projection 38 of bracket 40 of plate I5, but also holds the collar in position on the companion terminal member, each collar havin end portions I08 which releasably engage part of the companion terminal member, as clearly shown in Fig. 6. Thus, thermostatic strips 34 are mechanically secured for individual adjustment thereof and are electrically connected at their reflexed end portions 42 to the companion line terminals, respectively. The thermostatic strips 34 are electrically connected to the companion poles, respectively, of the switch by flexible conductors or pig-tails IIO which are soldered or otherwise secured to the companion strips, respectively, near the ends 35 thereof. The connections of conductors IIO with the contacts of switch I4 will be hereinafter more specifically described. It will be understood, however, that while as here shown, the current which passes through each pole of the switch passes through a companion bimetallic strip 34, so that each strip is responsive directly to the current flowing in the line controlled by the companion contacts of the corresponding pole of the switch, it is within the scope of the present invention to utilize current responsive means of other types for controlling the operation of trip-releasing member I5,

The preferred construction and operation of switch I 4 under the control of the tripping device I and the means for resetting said tripping device will now be described, it being understood, however, that although the preferred form of circuit breaker includes a switch I4 of the type presently to be described, said tripping device may be combined with 'other types of multipole switches and is not limited to its use in combination with this preferred type of switch.

As here shown, switch I4 comprises a plurality of operating members H2, H4 and H5, one for each pole of the switch, each of said operating members being formed of insulation material. The intermediate operating member H4 is provided with a knob or operating handle II8 which projects through an opening I20 in the casing cover I22. The three operating members are mounted for pivotal movement in the manner presently to be specifically described, and are interlocked with each other for conjoint pivotal movement as a unit. For this purpose the intermediate operating member H4 is provided with lateral projections or tongue portions I24 and I25 which are received in grooves I30 and I28, respectively, in the adjacent operating members I I and H2. Said operating members have arcuate portions I32, I34 and I35, respectively, integral and projecting laterally of both sides of radial portions I38, I40 and I42 of said operating members. Each of said radial portions of the operating members includes a hub portion I44, each of which has axially spaced co-axial tubular recesses I45 and I48 (Fig. The three operating members are assembled in co-axial relation by cylindrical pins I50 of the longitudinal sectional construction illustrated in Fig. 10. Each pin has end portions I52 and I54 0! diiierent diameters which are received in the recesses I and I45, respectively, or the hub portions I44 .0: adjacent operating members, said end portions I52 and I54 snugly fitting in said recesses, respectively. A metal pin I is associated with operating member I I2, said pin having a longitudinally extending cylindrical portion I52 snugly fitting in recess I48 of member II2, an intermediate cylindrical portion I54 0! larger diameter than portion I52 and an end cylindrical portion I55 of yet larger diameter. A metal pin I08 is associated with operating member I I5, said pin having a cylindrical portion I10 which snugly fits in recess I45 01' said operating member H5 and an end portion I12 of smaller diameter. The end portions I55 and I12 of pins I50 and I58, respectively, form trunnions for pivotally mounting the assembly or the operating members in the casing. The bearings for said assembly of operating members are constituted, as here shown, by metal strips I14 mounted and fitting in grooves I15 in the opposite side walls I18 of casing I2, said grooves being open at the top to permit the insertion of said bearing members I14. The latter are secured in position in the companion grooves in any suitable way as by screws I50 threaded through the side walls I18 and into thereaded openings in said bearing members I14. Bearing openings I 82 provided in member I14 and portions I55 and I12 of pins I50 and I58 are journalled for pivotal movement in said bearing openings.

A pair of relatively'movable contacts I54 and I85 is associated with each of said operating members H2, H4 and H5. The contact member I84 of each pair is fixed to, and carried by, a metal lever arm I88 mounted for turning movement on portions I55 of pins I50, in the case or operating members H4 and H5, and on portion I54 01 pin I50, in the case of operating member II2, lever arms I88 being held against movement axially of said operating members by reason of the position of said lever arms between the adjacent end of adjacent hub portion I44 of the companion operating member and the shoulder formed by the larger portions I58 and I55 of pins I50 and I50, respectively. Contacts I84 are thus held in alignment with their companion contacts I85. Each lever arm I88 is biased for movement to circuit interrupting position for moving contact member I84 away from the companion contact member I85 by a spring I which is coiled around a part of hub portion I44 and has one end I92 thereof in engagement with the companion lever arm I88 and the other end portidn I84 thereof in engagement with the adjacent end of the arcuate portions I32, I34, I35 of companion operating member. The movements of lever arms I88 on their companion pivot pins away from the companion contacts I85 are limited by the engagement of said arms with the ends I88 of the arcuate portions I32, I34 and I36, respectivel of the companion operating members.

The flexible conductors or pig-tails IIO which are connected to the thermostatic strips 34 are electrically connected to said arms I 88, respectively, preferably by soldering said flexible conductors to said arms. The companion contact I85 of each pair of contacts is carried by a contact member I85 fixedly secured to and movable with the companion operating members H2, H4

members 200 are secured to said wall portion 202 by companion screws 204, which are entered through a groove 206 formed in said end wall portion 202. Lead-terminal connectors 208 are secured to companion terminal members 280 by the screws 204 which fasten said terminal members to wall portion 202. Vertical wall portions 210 provide barriers between adjacent terminal members and lead-terminal connectors.

The three lever arm 188 are interconnected by a cross bar 201 forming part of the trip-released means 32. Offset end portions 208 (Fig. 13) of lever arms 188 are fixed in laterally spaced openings 211, respectively, in said cross bar and are secured thereto in any suitable way as by pins 212. The above mentioned trip-released plate 38, havin the trip-released element 28 which is releasably engaged by the detent 26 of trip-releasing member 16, is'flxed to said bar by any suitable means, here shown as rivets 214. It will be observed that the trip-released means for disengaging contacts 184 from the companion contacts 185, respectively, at the several poles of the circuit breaker, include the springs 190 which are operable to move lever arm 188 to circuit interrupting position when the trip-released member is moved to a retracted position for disengaging detent 28 from the trip-released element 23 of trip-released member 32 (Figs. and 11).

When the lever arms 188 which carry the contacts 188 are in set position, as illustrated in Fig. 2, being retained in said position by the engagement of detent element 26 with the tripreleased element 28 of trip-released member 32, the companion contact members 186 are movable by the manually operated members 112, 114 and 116 out of engagement with the contacts 184, respectively, by turning said operating members counter-clockwise (viewing Fig. 2), against the spring pressure of the snap-action springs 218, from the position illustrated in Fig. 2 to the position illustrated in Fig. 12. Conversely, the contacts 18B are movable by the manually operable members 112, 114 and 116 to the circuit closing position illustrated in Fig. 2, by moving said manually operated members clockwise (viewing Fig. 12) to the position illustrated in Fig. 2 in which contacts 185 engage the companion contacts 184, respectively, and are held in said engagement by the snap action springs 216. It will be noted that said sprin s 2i6 form toggles with the operating members 112 and 116, which as explained above are interlocked with operating member 114, whereby in the manual operation of switch 14 by knob 118 companion contacts 184 and 186 at each pole are both opened and closed with a snap action. It will be noted also that springs 216 hold the operating members 112, 114 and 116 in the position illustrated in Fig. 2, in the set condition of the switch, in which position knob 118 is spaced from the adjacent confronting edge 218 of opening 120 so that when the trip-released member 16 is retracted, springs 216 are effective to move said operating members from the position illustrated in Fig. 2 to the position illustrated in Fig. 11, in which knob I18 engages the confronting edge 218 of opening 120. When the switch is manually opened as illustrated in Fig. 12, knob 118 engages the op-v posite confronting edge 220 of opening 120 which acts as a stop for the operating members 112, 114 and 116 and limits the movement of the latter in a counter-clockwise direction.

When the switch is to be manually closed,

- tripping switch 14.

and the trip-releasing device 16 is in set position, turning the operating members 112, 114 and 116 (by knob 118) in a clockwise direction, viewing Fig. 12, the trip-released element 28 is enaged with the trip-releasing detent 28, after which the lever arm 188 and the contacts 184 carried thereby remain stationary during the continued movement of said operating members in the same direction, while contacts 186 continuing to move with said operating members in said some direction of the latter are brought into engagement with said contacts 184. More specifically, when opera- ting members 112, 114 and 116 are actuated for closing the switch, the trip-released element 28 engages detent 26 before the contacts 184 engage their companion contacts 188, respectively, so that lever arms 188 are held stationary during the rest of the movement of said operating members in switch closing direction, and during that time ends 105 of the arcuate portions of said operating members are in engagement with ends 184 of the companion springs so that said springs are stressed and thereby conditioned to move the lever arms in a clockwise direction (viewing Fig. 2) away from their companion contacts 186, respectively (Fig. 11), when the trip-releasing detent 26 disengages trip-released element 28, in tripping the switch upon the occurrence of an'overload.

It will be noted that when the switch is trip by the movement of the trip-releasing member 15 to a retracted position, contacts 188 move for a short distance in the same direction as the companion separable contacts 184, which is desirable especially when the circuit breaker is used for interrupting an alternating current circuit, since this action decreases arcing at the companion separable contacts during the separation of said contacts.

Provision is made for resetting the trip-releasing device 10 following the actuation thereof for For this purpose member 20 has a cam element 222 positioned to be releasably engaged by a roller 224. Said roller 224 is carried by metal arms 226 fixed to the opposite sides, respectively, of a radial portion 228 of operating member 1 14 below the pivotal axis thereof. Said arms are rigidly secured to said part 228 in fixed relation thereto in any suitable way as by a bolt 230. The inner ends of arms 226 abut against lateral projections 232 on operating member 114 and are thereby held against turning movement with respect to said operating member. As here shown, roller 224 is mounted on a pin 234 extending between and fixed in said arms 226. When it is desired to reset the tripping device 10, following the actuation thereof for tripping the switch, pursuant to the occurrence of an overload in one or all of the lines controlled by said switch, knob 118 is moved from the position illustrated in Fig. 11 to the position illustrated in Fig. 12, and during this movement the trip-released element 28 is moved to a position above trip-releasing detent 28 before trip-releasing member 26 is moved to its final projected or set position followingwhich, as part of the same continuous movement of knob 118 from the position illustrated in Fig. 11 to the position illustrated in Fig. 12, roller 224 by its engagement with the cam surface 238 of resetting cam 222 moves plate 18 of trip-releasing member 16 beyond the outer ends of thermostatic strips 34 which, having cooled sufiiciently following the interruption of current therethrough, flex into the plate holding position illustrated in Fig. 12, thereby releasably jected position to a, retracted aearsso engaging said plate and holding the latter in set position. After the trip-releasing device is thus set, the switch can be closed by moving knob Ill from the position illustrated in Fig. 12 to the position illustrated in Fig. 2. In this position, the cam operating roller 224 is clear of mm 222, as illustrated in Fig. 2, so that upon the occurrence of an overload the trip-releasing member i6- is free to move to its retracted position without interference by the resetting device.

Springs 2lt are preferably, but not necesmrily, of the construction illustrated. As here shown, each spring has an end portion 238 disposed in an open-end slotted portion 240 of a radial part 242 of the companion operating member H2 or H6. Said end 238 is integral with the arms 2 formed as continuations of the axially displaced coiled portions 2. The other ends of the coiled portions extend into the arms 2 and terminate in confronting end portions 250 which en e in a groove 252 in a part 254 at the bottom of casing i2.

Casing "is provided with laterally spaced partition members 250 provided with arcuate grooves 258. Fibre or other insulation disks 2" are mounted at opposite sides of operating member I It to provide arc barriers between adjacent pairs of companion contacts. These insulation disks are movable with the operating members, and have their peripheral portions thereof received in and movable circumferentially of grooves 258 of barriers 2!.

As various changes may be made in the apparatus herein disclosed or illustrated, without departing from the underlying idea of the present invention, we do not wish to be limited to the construction herein shown or described, except to the extent which maybe required by the scope of the appended claims.

Having thus described our invention, what we claim and desire to secure by Letters Patents is:

1. A tripping device for a multi-pole switch, comprising a trip-releasing member, a plurality of circumierentially spaced members, means fixed to said trip-releasing member and slidably engaging said spaced members for mounting said trip-releasing member for movement from a projected position to a retracted position, means biasing said trip-releasing member to said retracted position thereof, and a plurality of ourrent-responsive members, one for each pole of the switch, releasably engageable with circumferentially spaced parts, respectively, of said tripreleasing member for releasably holding said trip-releasing member in said projected position thereof.

2. A tripping device for a multi-pole switch,' comprising a trip-releasing member, a plurality of circumierentially spaced members, means fixed to said trip-releasing member and slidably enmembers from a retracted position to a projected position, a plurality of guide members in fixed relation to said plate and slidably engaging said supporting members, respectively, a plurality of clrcumferentially spaced members in fixed relation to said plate and projecting radially thereof, means biasing said plate to said retracted position thereof, and a plurality of current-responsive members, one for each pole of the-switch, releasably engageable with said radial projecting members, respectively, for releasably holding said trip-releasing member in said projected position thereof.

4. A tripping device for a multi-pole switch, comprising a plurality of supporting members, a plate mounted for movement on said supporting members from a retracted position to a projected position, a plurality of circumferentially spaced members in fixed relation to said plate and projecting radially thereof, means biasing said plate to said retracted position thereof, and a plurality of current-responsive members, one for each pole of the switch, releasably engageable with said radial projecting members, respectively, for releasably holding said trip-releasing member in i said projected position thereof.

5. A multi-pole tripping device comprising a trip-releasing member mounted for movement from a set position to a retracted position, three current-responsive members releasably engaging said member at three triangularly related points for holding said trip-releasing member releasably in said set position, means for mounting said trip-releasing member for said movement thereof, said trip-releasing member being tiltable on said mounting means to a retracted position when less than the three of said current-responsive members engage said trip-releasing member, and spring means exerting pressure on said tripreleasing member for holding said trip-releasing member in said engagement with said three current-responsive members and for moving said trip-releasing member to a retracted position when disengaged by one or more 01' said currentresponsive members.

6. A tripping device for a, multi-pole circuit breaker having a trip-released member, said tripping device comprising a trip-releasing member mounted for movement from a projected or set position to a retracted or released position, a plurality oi current-responsive members, one for each pole of the circuit-breaker, for releasably holding said trip-releasing member in said set position, means operable under the control of each of said current-responsive members for moving said trip-releasing member to said regaging said spaced members for mounting said trip-releasing member for movement from a proposition, said last. mentioned means comprising a plurality of circumferentially spaced members having radial projection means biasing said trip-releasing member to said retracted position thereof, and a plurality of current-responsive members, one for each pole of the switch, releasably engageable with said radial projection-s, respectively, for relra ably holding said trip-releasing member in said projected position thereof.

3. A tripping device for a multi-pole switch, comprising a plurailty of supporting members, a plate mounted for movement on said supporting tracted or released position, a detent element carried by said trip-releasing member and releasably engageable with said trip-released member of the circuit-breaker for holding the circuitbreaker' closed, and a resetting cam carried by said trip-releasing member and releasably engageable by a part of the circuit-breaker for moving said trip-releasing'member to said set position thereof.

7. A tripping device for a multi-pole switch, said device comprising a plurality of currentresponsive members, one for each'pole of the switch, responsive to the current in the line of the companion pole, a trip-releasing member mounted for movement, said current-responsive members normally holding said trip-releasing member conjointly against movement in one direction; said current responsive members having movable portions positioned normally in said holding relation at points spaced equally of the circumference of a circle and movable, respectively, out of said member-holding relation upon the occurrence of an overload in the line of the companion pole whereby movement of said tripreleasing member in said direction occurs upon said movement of any one or all of said currentresponsive members, said trip-releasing member having a detent element positioned in line with the center of said circle, and a resetting element carried by said trip-releasing member for moving said trip-releasing member in a direction opposite to said first mentioned direction.

8. A multi-pole circuit breaker comprising a plurality of pairs of companion separable contacts, one pair for each pole, manually operable means for engaging and disengaging said companion contacts with each other at each of said poles, respectively, trip-released means for disengaging said companion contacts from each other at each of said poles, respectively, tripreleasing means controlling the operation of said trip-released means, said trip-releasing means comprising a trip-releasing member movable from a set position to a retracted position, current responsive means engageable with said tripreleasing member in said set position thereof for releasably holding said trip-releasing member in said set position, spring means for moving said trip-releasing member to a retracted position when disengaged by said current responsive means, said trip-releasing member having a resetting part secured thereto, and means fixed to said manually operable means in non-movable relation thereto and engageable with said resetting part for moving said trip-releasing member to said set position thereof for said engagement by said current responsive means.

9. A multi-pole circuit breaker comprising a plurality of pairs of companion separable contacts, one pair for each pole, a plurality of movable members each of which carries one of said companion contacts of one of said pairs, said movable members being movable from circuitclosing positions to circuit-interrupting positions and interconnected for conjoint movement, spring means for moving said movable members to said circuit-interrupting positions, manually operable means for moving said movable members to said circuit-closing positions, trip-releasing means for releasably preventing said spring means from moving said movable members to said circuit-interrupting positions, said trip-releasing means comprising a movable trip-releasing member mounted for movement from a set position to a retracted position, and three current-responsive members releasably engageable with said trip-releasing member at three triangularly related points whereby the engagement of all of said current-responsive members with said tripreleasing member is required to hold the latter in said set position thereof.

10. A multi-pole circuit breaker comprising a plurality of pairs of companion separable contacts, one pair for each pole, a plurality of movable members each of which carries one of said companion contacts of one of said pairs, said movable members being movable from circuitclosing positions to circuit-interrupting positions and interconnected for conjoint movement, spring means for moving said movable members to said circuit-interrupting positions, manually operable means for moving said movable members to said circuit-closing positions, trip-releasins means for releasably preventing .said spring means from moving said movable members to said circuit-interrupting positions, said trip-releasing means comprising a movable trip-releasing member mounted for movement from a set position to a retracted position, and three current-responsive members releasably engageable with said trip-releasing member at three triangularly related points whereby the engagement of all of said current-responsive members with said trip-releasing member is required to hold the latter in said set position thereof, said trip-releasing member carrying a detent element and a resetting cam, a trip-released member releasably engageable by said detent element for releasably holding said movable members in said circuitclosing positions, and means actuated by said manually operable means and engageable with said cam for moving said trip-releasing member to a position in which said detent element is engageable by said trip-released member, each of the other companion contacts being carried by said manually operable means and movable thereby into .and out of engagement with the contacts carried by said movable members when said trip-released member is engaged by said detent element.

11. A tripping device for a multi-pole switch, said device comprising a plurality of currentresponsive members, one for each pole of the switch, responsive to the current in the line of the companion pole, a trip-releasing member mounted for movement, said current-responsive members normally holding said trip-releasing member conjointly against movement in one direction, said current-responsive members having movable portions positioned normally in said holding relation at points spaced equally of the circumference of a circle, and movable, respectively, out of said member-holding relation upon the occurrence of an overload in the line of the companion pole whereby movement of said tripreleasing member in said direction occurs upon said movement of any one or all of said currentresponsive members, and a trip-released member mounted for movement from a set position to a released position and movable to said last mentioned position under the control of said tripreleasing member said trip-releasing member including a part positioned substantially at the center of said circle and normally engaging said trip-released member to prevent said movement thereof to said released position and movable with said trip-released member to release said tripreleased member for movement thereof to said position, and means for resetting said trip-releasing and trip-released members following the movements thereof to said trip-released positions.

12. A tripping device for a multi-pole switch, said device comprising a trip-released member and a trip-releasing plate, each mounted for movement from a set or normal position to a trip-released position, means biasing said member and said plate to said last mentioned positions thereof, thermostatic strips for releasably holding said plate in said normal position thereof, each strip fixed at one end thereof and movable at its opposite end, said thermostatic strips having their movable ends positioned in said plateholding relation at points spaced equally of the circumference of a circle, and means positioned substantially at the center of said circle and movable with said plate for releasably holding said trip-released member in said normal position thereof, said means releasing said trip-released member for movement to said tripreleased position thereof when said plate moves to' its said trip-released position.

13. A tripping device for a multi-pole switch, said device comprising a trip-released member and a ifltrip-releasing plate, each mounted for movement from a set or normal" position to. a trip-released position, means biasing said member and said plate to said last mentioned positions.thereof, thermostatic strips for releasably holding said plate in said normal position thereof, each strip fixed at one end thereof and movable at its opposite end, said thermostatic strips having their movable ends positioned in said plateholding relation at points spaced equally of the circumference of a circle, means positioned substantially at the center of said circle and movable with said plate for releasably holding said tripreleased member in said normal position thereof, said means releasing said trip-released member for movement to said trip-released position thereof when said plate moves to its said tripreleased position, and means for resetting said trip-released member and said plate in said normal positions thereof, respectively.

14. A multi-pole switch and a tripping device for simultaneously opening the switch at all of the poles thereof upon the occurrence of an overload in any line controlled by the switch, said tripping device comprising a plurality of currentresponsive members, one for each pole of the switch, responsive to the current in the line of the companion pole, a trip-releasing member mounted for movement, said current-responsive members normally holding said trip-releasing member conjointly against movement in one direction, said current-responsive members having movable portions positioned normally in said holding relation at point spaced equally of the circumference of a circle, and movable, respectively, out of said member-holding relation upon the occurrence of an overload in the line of the companion pole whereby movement of said trip releasing member in said direction occurs upon said movement of any one or all of said currentresponsive members, a trip-released member mounted for movement from a set position to a released position and. movable to said last mentioned position under the control of said trip-releasing member, said trip-releasing member iricluding a part positioned substantially at the center of said circle and normally engaging said tripreleased ,member to prevent said movement thereof to said released position and movable with said tripreleased member to release said trip-released member for movement thereof to said position, said switch havingcompanion relatively movable contact members at each of said poles thereof, means operable to effect simultaneous separation of all of said contact members, and means operable under the control of said trip-released member for releasably preventing operation of said contact-member separating-means.

15. A multi-pole switch and a tripping device for simultaneously opening the switch at all of the poles thereof upon the occurrence of an overload in any line controlled by the switch, said tripping device comprising a trip-released member and a trip-releasing plate, each mounted for movement from a set or normal position to a tripreleased position, means biasing said member and said plate to said last mentioned positions thereof, current-responsive members for releasably holding said plate in said normal position thereof, said current-responsive members having movable ends positioned in said plate-holding relation at points spaced equally of the circumference of a circle, means positioned substantially at the center of said circle and movabl with said plate for releasably holding said trip-released member in said normal position thereof, said means releasing said' trip-released member for movement to said trip-released position thereof when said 1 member separating-means.

16. A multi-pole switch and a tripping device for simultaneously opening the switch at all of the poles thereof upon the occurrence of an overload in any line controlled by the switch, said tripping device comprising a plurailty of bimetallic strips, one for each pole of the switch, responsive to the current in the line of the companion pole, a single trip-releasing member mounted for movement, said strips normally releasably engaging and holding said member conjointly against movement in one direction, said strips being movable, respectively, out of said member-holding relation upon the occurrence of an overload in the line of the companion pole whereby movement of said member in said direction occurs upon said movement of any one or all of said strips, a'trip-released member releasably engaged by said trip-releasing member and mounted for movement from a set position to a released position and movable to said last mentioned position under the control of said trip-releasing member, said switch having companion relatively movable contact members at each of said poles thereof, means operable to effect simultaneous separation of all of said contact members, means operable under the control of said trip-released member for releasably preventing operation of said contact-member separating-means, means for closing the switch, and means actuated under the control of said switchclosing means for resetting said members following the movements thereof to said trip-released positions.

1'7. A multi-pole switch and a tripping device for simultaneously opening the switch at all of the poles thereof upon the occurrence of an over load in any line controlled by the switch, said tripping device comprising a trip-released member and a trip-releasing plate, each mounted for movement from a set or normal position to a tripreleased position, means biasing said member and said plate to said lastmentioned positions thereof, thermostatic strips for releasably hold in said plate in said normal position thereof, each strip fixed at one end thereof and movable at its opposite end, said thermostatic strips having their movable ends positoned in said plateholding relation at points spaced equally of the circumference of a circle, means positioned substantially at the center of said circle and movable with said plate for releasably holding said tripreleased member in said normal position thereof, said means releasing said trip-released member for movement -to said trip-released positon thereof when said plate moves to its said tripreleased position, said switch having companion members, means operable under the control of said trip-released member for releasably preventing operation of said contact-member separating-means, means for closing the switch, and means actuated under the control or said switchciosing means for resetting said trip-released member and said plate in said normal positions thereof, respectively.

18. A tripping device for a muiti-pole switch, said device comprising a trip-released member and a, trip-releasing plate, each mounted for movement from a set or normal position to a tripreleased position, means biasing said member and said plate to said last mentioned positionsthereof, thermostatic strips for releasably holding said plate in said normal position thereof, each strip fixed at one end thereof and movable at its opposite end, said thermostatic strips having their movable ends positioned adjacent edge portions of said plate in abutting relation to said plate at one side thereof at points spaced equally of the circumference of a circle, and a stop member carried by said plate on the other side thereof at a point located substantially at the center of said circle, said stop member being normally in the path of movement of said trip-released member to its trip-released position and thereby preventing said movement of said member and movable by said plate out of said path for releasing said trip-released member for movement to its said trip-released position.

19. A tripping device for a multi-pole switch, said device comprising a trip-released member and a trip-releasing plate, each mounted for movement from a set or normal position to a tripreleased position, means biasing said member and said plate to said last mentioned positions thereof, thermostatic strips for releasably holding said plate in said normal position thereof, each strip fixed at one end thereof and movable at its opposite end, said thermostatic strips being disposed at one side of said plate in angular relation thereto and having their movable ends positioned adjacent edge portions of said plate at points spaced equally of the circumference of a circle, and a stop member carried by said plate at a point located substantially at the center of said circle, said stop member being normally in the path of movement of said trip-released member to its trip-released position and thereby preventing said movement of said member and movable by said plate out of said path for releasing said trip-released member for movement to its said trip-released position.

20. A tripping device for a multi-pole switch, said device comprising a trip-released member and a trip-releasing plate, each mounted for movement from a set or normal position to a trip-released position, means biasing said member and said plate to said last mentioned positions thereof, thermostatic strips for releasably holding said plate in said normal position thereof, each strip fixed at one end thereof and movable at its opposite end, said thermostatic strips being disposed at one side of said plate in angular relation thereto and having their movable ends positioned adjacent edge portions of said plate at points spaced equally of the circumference of a circle, a stop member carried by said plate at a point located substantially at the center of said circle, said stop member being normally in the path of movement of said strip-released member to its trip-released position and thereby preventing said movement of said member and movable by said plate out of said path for releasing said trip-re- 16 leased member for movement to its said trip-released position, and means for resetting said tripreleased member and said plate in said normal positions thereof, respectively.

21. A muiti-pole switch and a tripping device for simultaneously opening the switch at all of the poles thereof upon the occurrence of an overload in any line controlled by the switch, said tripping device comprising a trip-released member and a trip-releasing plate, each mounted for movement from a set or normal position to a tripreleased position, means biasing said member and said plate to said last mentioned position thereof, thermostatic strips for releasably holding said plate in said normal position thereof, each strip fixed at one end thereof and movable at its opposite end, said thermostatic strips being disposed at one side of said plate in angular relation thereto and having their movable ends positioned adjacent edge portions of said plate at points spaced equally of the circumference of a circle, and a stop member carried by said plate at a point located substantially at the center of said circle, said stop member being normally in the path of movement of said trip-released member to its trip-released position and thereby preventing said movement of said member and movable by said plate out of said path for releasing said trip-released member for movement to its said trip-released position.

22. In a tripping device for a multi-poie switch, a tripping member mounted for tilting movement from a set position to a released position, and three triangularly arranged current-responsive thermostatic strips releasably engageabie with said tripping member for holding the same in set position, said tripping member and said strips being constructed and arranged so that all three of said strips act conjointly to hold said tripping member in said set position thereof and so that said tripping member is movable to said released position thereof when any one of said thermostatic strips releases said tripping member.

23. In a tripping device for a mu'lti-pole switch, a tripping member mounted for tilting movement from a set position to a released position, and three trianguiarly arranged current-responsive latching members releasably engageable with said tripping member for holding the same in set position, means biasing said tripping member for movement to said released position thereof, said tripping member and said latching members being constructed and arranged so that all three of said latching members act conjointly to hold said tripping member in said set position thereof and so that said tripping member is movable to said released position thereof when any one of said latching members releases said tripping member.

24. In a multi-pole circuit breaker, a tripping device comprising a releasing plate, supporting means on which said plate is tiltably movable from a set position to a retracted position, three thermostatic strips, one for each pole of the circuit breaker, extending longitudinally in laterally spaced relation and each having one of its ends in releasable engagement with said plate, said thermostatic strips being responsive to the current in the lines of the companion poles, respectively, of the circuit breaker, said plate-engaging ends of said strips engaging said plate at the points of a triangle whereby upon the release of one of said ends from said plate the latter tilts on said supporting means to said retracted position, and means operable in response to the movement of said plate to said retracted position for opening the circuit breaker at a plurality of the poles thereof.

25. In a multi-pole circuit breaker, a tripping device comprising a releasing plate, supporting means on which said plate is tiltably movable from a set position to a retracted position, three thermostatic strips, one for each pole of the circuit breaker, extending longitudinally in laterally spaced relation and each having one of its ends in releasable engagement with said plate, said thermostatic strips being responsive to the current in the lines of the companion poles, respectively, of the circuit breaker, spring means holding said plate releasably against said ends of said strips and biasing said plate for movement to said retracted position thereof, and means operable in response to the movement of said plate to said at a plurality of the poles retracted position for opening the circuit breaker thereof.

LOUIS W. COLE. THOMAS M. COLE.

REFERENCES CITED The following references are of record in the file of this patent:

I UNITED STATES PATENTS Number

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