US2577230A

US2577230A - Latch tripping mechanism comprising abutting pivoted members

Info

Publication number: US2577230A
Application number: US160652A
Authority: US
Inventors: John F Chipman
Original assignee: Allis Chalmers Corp
Current assignee: Allis Chalmers Corp
Priority date: 1950-05-08
Filing date: 1950-05-08
Publication date: 1951-12-04
Anticipated expiration: 1968-12-04

Description

Dec. 4, 1951 J. F. cHlPMAN LATCH TRIPPING MECHANISM COMPRISING ABUTTING PI VOTED MEMBERS 2 SHEETS- SHEET l Filed May 8, 1950 DCC. 4, 1951 J. F. cHlPMAN LATCH TRIPPING MECHANISM COMPRISING ABUTTING PIvoTED MEMBERS 2 SHEETS- SHEET 2 Filed May 8, 1 950 Patented Dec. 4, 1951 LATCH TRIPPIN G MECHNISMv COMPRISING ABUTTING PIVOTED MEMBERS John F. Chipman, South Weymouth,- Mass., assignor to Allis-Chalmers Manufacturing Company,l Milwaukee, Wis.

Application May 8v, 1950, Serial N0. 160,652

(CL I4-2) 7 Claims.

This invention relates generally to operating mechanisms for electric circuit breakers which are latched closed against an opening biasing force, and more particularly to tripping'means for unlatching and causing opening of thecircuit breakers by the biasing force. y

Circuit breakers of this general type, and particularly multipole circulit breakers which are designed to interrupt heavy currents, are of rugged construction and usually employ strong springs lto operate the contacts between closed and opened positions. The tripping device which cooperates with a releasable contact operating structure for normally latching a releasable member must be designed to withstand considerable strain because it absorbs part' of the force of the contact operating springs when it unlatches the releasable member.

Tripping devices heretofore provided have been designed as a unitary structure', and' the reactions of the contact operating mechanism during an unlatching operation have resulted in the creation of a given excessive amount of kinetic energy which must be absorbed before the trippingdevice comes to rest. If` the weight of the tripping device were substantially decreased. to reduce the kinetic energy resulting from the movement thereof,.the device would not be able to stand the forceV transmitted to it from the contact springs.v

In accordance with the invention claiined'a new and improved tripping device is provided comprising a pivoted force receiving member and a pivoted force transmitting member. The force transmitting member upon movement thereof actuates the force receiving member to move a latch to release a member which operates a contact vactuating structure. Upon release of the contact actuating structure, the force receiving member is further actuated -in latch releasing direction by the contact actuating springsindependently of the force transmitting member.

.The force transmitted to the tripping device by the contact actuating springs results inraccelerating only a part of the tripping device and consequently the resultant kinetic energyproduced is less than the kinetic energy produced by the unitary tripping devices heretofore used.

It is', therefore, one object ofA the-presenty invention to provide a new and improved tripping device for unlatching electric circuit breakers in which a pivoted forceV receiving. member is divorced during actuation of the:V tripping device from a pivoted force transmitting'm'ember;k

`Another object of thiszinventioniis.tofprovide a new andr improved tripping device for electric circuit breakers in which a pivoted force receiving member and a pivoted force transmitting member cooperate to move together during an unlatching operation, but move independently of eachother aiter the unlatching operation.

vA further object of this invention is to pro'- vide a new and improved tripping device for electric circuit breakers in which a pivoted force transmitting member actuates a pivoted force receiving member upon actuation or' the tripping device and arcing Contact springs further actuate the force receiving member upon move-'- ment oi' the arcing contacts thereof.

Objects and advantages other than those set forth will be apparent from the following description when read in connection with the accompanying drawings in which:

Fig. 1 is a sectional View of an operating mechanism embodying the present invention;

Fig.`2 is an enlarged sectional View of a part of thetripping device illustrated in Fig. l taken alongline 11F-'II in Fig 3;

Fig. 3 is airont view ofthe embodiment illustrated in Fig. 2 with part ofV the elements removed; and

Figs: 4k to 6 show in cross-section three dierent positionsA of the tripping device and associated linkage by which the circuit breaker is operated and restrained' in closed circuit position.

Referringmore particularly to the drawing by characters oi reference, Figs. 1 to 6 illustrate part ora magnetic blowout type circuit breaker Il' andan operating mechanism i2. The latter comprises a iorce transmitting structure I3 and a tripping means iii'. Although circuit breakers of the `type herein considered are frequently provided with a plurality oi" similar pole structures, one for each phase of a polyphase electric circuit',l only one such pole structure or pole unit isshownin Figs. 1 to 6 and the circuit breaker will be described in detail as if it were of the single pole type.

Circuitfbreaker il illustrated in Fig'. l/inclu'des as elements thereof a pair of terminal studs l5 (only one of. which is shown) for connecting the circuitl breaker to line conductors (not shown). Breaker lf-I comprises essentialy meansfor open- Ving the Vcircuit to form an arc, and an arc extinguishing structure.r Specifically, the circuit opening means comprises a ixed arcing` contact I6 and a movable arcing contact H. Arcing contact Il is mounted ona lever i8 which is pivotal-ly mounted at I9 on an extension arm 20 of one-Cof thel circuit breaker studs (not shown) 3 and is operated by means of a connecting rod 2l of insulating material forming a part of the force transmitting structure I3 for operating the movable Contact between closed and open circuit positions. Fig. 1 illustrates the movable arcing contact I1 in the closed circuit position.

For the purpose of interrupting the arc formed upon separation of the arcing contacts, an arc extinguishing structure, such as an arc chute 24 (partly shown in Fig. 1) is mounted directly above the arcing contacts so as to receive the power arc when it is driven upward by a magnetic blowout means 25. The arc chute is disposed directly above the arcing contacts, as shown, when the blowout means act upward, but may be mounted in any other suitable location when the blowout means act in other directions. The arcing contacts and the magnetic blowout structure can assume any suitable known form so that a brief description thereof will be sufficient. The magnetic blowout means 25 comprises a core 26, poles 21, and a coil 28 which is inserted in the connection between the terminal stud I5, contact I6 and an arc runner 29, so that the arc current (as the arc travels along the runner) flows through the blowout coil in a manner well known in the art. Core 26 and .poles 21 embrace at least part of arc chute 24 for driving the arc into the chute and toward the exhaust end thereof.

The operating mechanism I2 illustrated is interposed between a solenoid 36 and the movable arcing contact I1. In the position shown in Fig. l, the circuit breaker is in the closed position and the operating mechanism is held in such vposition by a pivoted locking latch 3l forming a part of tripping means I4 and a tripping linkage or toggle 32.

In addition to toggle 32 comprising

links

35 and 36, the mechanism comprises a spring 31 which resiliently biases one end of link 35 to a frame 38. A bell crank 39 pivotally mounted to frame 38 at a point 40 has one arm thereof pivotally connected to link 35 and the other arm thereof pivotally connected at a point 4I to a connecting rod 42. A bell crank 43 is connected to rod 42 and to a connecting rod 2I.

A contacting actuating spring lmeans 45 is compressed between frame 38 and a collar 41 secured to one end of a connecting rod 46. The other end of rod 46 is pivotally connected to bell crank 39 at a point 4I, whereby a force transmitting structure I3 is completed between spring means 45 and contact lever I8.

Tripping means I4 comprises a force receiving member and a force transmitting member to move latch 3I to release toggle 32. The force transmitting member comprises a trip bar 48 of U-shaped cross section more clearly shown in Fig. 2. Trip bar 48 is provided with a bore 49 engaged by a screw 56 which is surrounded by a helical biasing spring I. Trip bar 48 forms an integral part of a structure comprising two lateral plates 54 and 55 (more clearly illustrated in Fig. 3) which are pivotally supported by a shaft 56.

Plates

54, 55 may havea running fit on shaft 56, which may be if so desired supported for rotation in bearings (not'shown) mounted on frame 38. The two

plates

54 and 55 are each provided with a hole 51 which minimizes their weight.

Plates

54 and 55 are rigidly interconnected by a tie bar 58.

The force receiving member of tripping means I4 comprises a block 59 in the shape of an irregular hexagon pivotally supported on shaft 56. 1

.for controlling Vlatch 3I. ,mounted on one arm of a bell crank 68, which 4 thus are supported for pivotal movement about a common axis. The lower surface of hexagonal block 59 abuts against tie bar 58, which interlocks the force transmitting and receiving members. Block 59 is provided with a pin 60 against which a rat-trap spring 6I rests. Rat-trap spring 6I biases hexagonal block 59 in the counterclockwise direction into engagement with tie bar 58, thereby interlocking the force transmitting and receiving members during movement thereof in latch releasing direction. Block 59 is provided with a pair of extension plates 62 which are rigidly secured to and form an integral part of block 59 and serve as a bracket for a supporting pin 63. Pin 63 supports a link 64 which cooperates with plates 62 to form a toggle A latch roll 61 is is secured to shaft 56 if the shaft is rotatable. The other arm of bell crank 68 is connected to link 35 through a pin 69. Latch roll 61 of the tripping means I4 is normally held in position by latch 3I. The position of bell crank 68 in turn determines the position of toggle 32. The force component transmitted from latch roll 61 to the latching surface of latch 3I is substantially normal to the latching surface and passes through the center of pin 66 around which latch 3I pivots. Latch 3I is held in position by link 64.

A toggle roll 10 isrmounted on a pin which 'interconnects

links

35 and 39 of toggle 32. Toggle roll 10 is arranged to move along surface 1I of frame 38 during the unlatching operation, thereby positioning toggle 32 so that it may jackknife under the force of spring 45.

Solenoid 12 comprising coil 14 and armature 15 is provided for reclosing circuit breaker II. Upon actuation of solenoid 12, armature 15 applies a force to toggle roll 1U and moves toggle 32 to its over center position. For manual closing, the closing force is applied on link 35 by means of bell crank 16, the rotation of which is controlled through a link 11 attached to end of manual closing crank 18 located at the front of the breaker. A latch check switch (illustrated in Fig. 2) needed for completion of the reclosing solenoid circuit is actuated by cam face 8I of the hexagonal block 59.

The actual tripping operation is best illustrated in Figs. 4 to 6 wherein Fig. 4 illustrates the circuit closed position of the operating mechanism I2, Fig. 5 an intermediate position of operating Amechanism I2, and Fig. 6 the open position of v59 resting on tie bar 58, which interconnects

lateral plates

54 and 55, is also rotated clockwise upon clockwise movement of

lateral plates

54 and 55 to break the

toggle

62, 64. The breaking of

toggle

62, 64 and the subsequent counterclockwise rotation of latch 3l releases the latch roll 61 of the restraining bell crank 63. Latch roll 61 rides out of the notch in latch 3I and is forced upward with toggle 32 by the reacting force of spring 45 acting on bell crank 39. Toggle 32 moves upward into the position shown in Fig. 5, thereby completely releasing spring 45 which instantly separates the arcing contacts.

Upon release of latch roll 61. from the notch of latch 3| the force component transmitted from gettate latch roll 6,1 to latch U31- accelerates the unit comprising block 59, extension plates 6 2, pin 6?,` link 69; and*A latch 3i, thereby..unlocking the." force transmitting and receiving-,meansg vThis force component being directly-proportional to the size of spring l5 and the degree to which it is compressed is of considerable magnitude and results, therefore, in a very high acceleration' offthe force receiving member ofV tripping device I4.

In accordance with the inventionV the force receiving member of tripping means i4 ifsdivorced from the force transmitting member, and the reaction which is transnfiitted-v from the latch to the other parts of the forcereceivingmember is not transmitted from the latterto the-force transmitting member. The force receiving-member is free to rotate in the clockwise orlatch opening direction under thevaction ofI the latch reaction without aiecting the force transmitting member, and the members reach the position thereof shown inA Fig. 5. Because the force transmitting member is divorced from the force receiving member, the mass of the force receiving member may be much smaller than heretofore used, resulting in a substantial decrease of the kinetic energy that will be imparted to it, a reduction in the stresses imposed on the tripping device it, and an increase in the over-all speed of operation of tripping devices i4.,

While toggle 32 kmoves upWardr0ll 'lll thereof 'rolls along surface 'li of `frame 38 until toggle 3Q reaches the over center position and collapses into the position shown in Fig. 6 through the biasing action of spring 31. Upon deenergization of solenoid 3l), the force transmitting and receiving members of tripping device I return to their original position as shown in Fig. 6 through action of rat-trap spring 6l.

. Although `but one embodiment of the presentY thereof connected to said structure, spring meansV for causing collapse of said toggle and actuation of said structure, means including a latch for preventing collapse of said toggle, and means for actuating said latch to release said toggle l'comprising a pivoted force receiving member and a pivoted force transmitting member, said force transmitting member upon movement thereof actuating said force receiving member to move said latch to release said toggle, said toggle upon release thereof further actuating said force receiving member in latch opening direction independently of the movement of said force transmitting member.

2. An operating mechanism comprising a force transmitting structure and tripping means controlling said structure, said tripping means comprising a collapsible toggle having one link thereof connected to said structure, spring means for causing collapse of said toggle and actuation of said structure, 4means including a latch for preventing collapse of said toggle, and means` for actuating said latch to release said toggle transmitting structure land tripping means controlling saidstruc'ture, said tripping means comprising a collapsible toggle having one link thereof connected to said structure, aiirst spring means for causing collapse, of said toggle and actuation of said structure, 'means vincluding a latch for preventing collapse of said toggle, and means for actuating said latch to releasesaid toggle comprising a pivoted force receiving member, a pivoted force transmitting member, and a second spring means for biasing said force transmitting member tointerlock with said force receiving member during movement together in latch releasing direction, said toggle upon-reflease thereof unlocking said members and further actuating saidforce receiving member in latch opening direction independently of said force transmitting member.

' 4. An operating mechanism comprising aforce transmitting structure and tripping means controlling said structure, said tripping means comprising a collapsible toggle having one link thereof connected to said structure, spring means for causing collapse of said toggle and actuation of said structure, means including a latch for preventing collapse of said toggle, and means for actuating said latch to release said toggle comprising a pivoted force receiving member, a pivoted force transmitting member, and an abutting connection between said members for controlling the movement of said force transmitting member in one direction, said force transmitting member upon movement thereof actuating said force receiving member to move said latch to release said toggle, said toggle upon release thereof further moving said force receiving member in latch opening direction independently of the movement of said force transmitting member.

5. An operating mechanism comprising a force transmitting structure and tripping means controlling said structure, said tripping means comprising a iirst collapsible toggle having one link thereof connected to said structure, spring means for causing collapse of said toggle and actuation of said structure, means including a latch for preventing collapse of said toggle, and means for actuating said latch to release said toggle comprising a pivoted force receiving member, a pivoted force transmitting member, an abutting connection between said members for controlling the movement of said force receiving member in one direction, and a second collapsible toggle having one link thereof attached to said force receiving member and the other link thereof attached to said latch for locking said latch to restrain movement of said first toggle, said force transmitting member upon movement thereof actuating said force receiving member to collapse said second toggle and move said latch to release said first toggle, said first toggle upon release thereof further moving said latch and said force receiving member in latch opening direction independently of the movement of said force transmitting member.

6. `An operating 'mechanism comprising a force transmitting structure and tripping means controlling said structure, said tripping means comprising a collapsible toggle having one link thereof connected to said structure, a first spring means for causing collapse of said toggle and actuation of said structure, means including a latch for preventing collapse of said toggle, and means for actuating said latch to release said toggle comprising a pivoted force receiving member, a pivoted force transmitting member, an abutment member secured to said force transmitting member for controlling the movement of said force receiving member in one direction, and a second spring means biasing said force receiving member into engagement with said abutment member, said force transmitting member upon movement thereof actuating said force receiving member against the bias of said second spring means to move said latch to release said toggle, said rst spring means upon release of said toggle further actuating said force receiving member in latch opening direction against the bias of said second spring means independently of the movement of said force transmitting member.

7. An operating mechanism comprising a force transmitting lever, a bell crank having one arm thereof secured to said lever, a collapsible toggle having one link thereof connected to the other arm of said bell crank, a rst spring means for causing collapse of said toggle and actuation of said lever, Ymeans including a latch to lock said toggle in an over-center position, means for actuating said latch to release said toggle comprising a force receiving member, a force transmitting member, said members being supported for pivotal movement abouty a common axis, an abutment member secured to said force transmitting member for controlling the movement of said force transmitting member a predetermined distance in latch releasing direction, and a second spring means biasing said force receiving member into engagement with said abutment member, said force transmitting member upon movement thereof actuating said force receiving member against the bias of said second spring means to move said latch to release said toggle, said first spring means upon release of said toggle further actuating said force receiving member in latch opening direction against the bias of said second spring means independently of the movement of said force transmitting member.

' JOHN F. CHIPMAN.

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

UNITED STATES PATENTS Number Name Date 1,786,727 Adam Dec. 30, 1930 1,814,777 Wurdack July 14, 1931