US3158714A

US3158714A - Spring-close high speed breaker

Info

Publication number: US3158714A
Application number: US93805A
Authority: US
Inventors: James C Craig
Original assignee: ITE Circuit Breaker Co
Current assignee: ABB Inc USA; ITE Circuit Breaker Co
Priority date: 1961-03-06
Filing date: 1961-03-06
Publication date: 1964-11-24
Anticipated expiration: 1981-11-24

Description

Nov. 24, 1964 J. c. CRAIG 3,158,714

SPRING-CLOSE HIGH SPEED BREAKER Filed March 6. 1961 5 Sheets-Sheet 1 FIG.3

FIG.2

INVENTOR. James C.Crc|g FIG.I

flan? 5x4 540545 $9 yaw! ATTORNEYS.

Nov. 24, 1964 J. c. CRAIG SPRING-CLOSE HIGH SPEED BREAKER 5 Sheets-Sheet 2 Filed March 6, 1961 ATTORNEYS Nov. 24, 1964 J. c. CRAIG SPRINGCLOSE HIGH SPEED BREAKER 5 Sheets-Sheet 5 Filed March 6, 1961 ATTORNEYS.

Nov. 24, 1964 J. c. CRAIG SPRING-CLOSE HIGH SPEED BREAKER 5 Sheets-Sheet 4 Filed March 6, 1961 @N wal ATTORNEYS.

Nov. 24, 1964 J. c. CRAIG 3,158,714

SPRING-CLOSE HIGH SPEED BREAKER Filed March 6, 1961 5 Sheets-Sheet 5 INVENTOR. JJMEJ 6'. 064/6 United States Patent 3,158,714 SPRING-CLOSE HIGH SPEED BREAKER James C. Craig, Mount Ephraim, N.J., assignor to I-T-E Circuit Breaker Company, Philadelphia, Pa, a corporation of Pennsylvania Filed Mar. 6, 1961, Ser. No. 93,805 14 Claims. (Cl. 200-106) The instant invention relates to circuit breakers, and more particularly to circuit breakers having a novel manually operated high speed spring-closing means.

Circuit breakers presently in use are designed to perform rapid tripping operations in response to overload or short circuit current conditions which may occur in the circuit being protected. Once this fault condition has been corrected, the circuit breaker may then be reclosed. Since the circuit breaker is being closed into an energized circuit, the closing operation must be performed very rapidly. Failure to provide a rapid closing operation permits an arc to be drawn between the closing contacts just before the contacts become engaged. The are formed therebetween causes the contacts to heat up very rapidly. The intense heat generated by the arc will melt the contact surfaces causing the contacts to become welded together upon engagement. This is an extremely dangerous condition, since the contacts will fail to disengage in response to a tripping operation due to the welding effect. Such an are formed during the closing operation also causes a current loop to be formed between the cooperating contacts and the arc, resulting in a blow-off efiect. This blow-off effect tends to buck the closing force resulting in a pumping operation, thereby impeding the engagement of the cooperating contacts.

Circuit breakers of the prior art employ closing means which are activated by an energized spring. This closing spring is moved to the energized state by an electric motor driving means. The motor means, however, depends upon a source of electricity so that it may properly charge the closing spring. If the power source which the motor depends upon for its operation is unavailable at the time the closing operation is to be performed, the operator is powerless to close the circuit breaker. This results in an undue delay before the circuit being protected may be placed back in operation.

The mechanism of my invention is designed to perform the closing operation in a very rapid manner. A novel prop-latch means incorporated in the device prevents the occurrence of a pumping action. The closing springs of my device are charged by a manual operation, thereby permitting the closing operation to be performed independent of any motor charging means as in the case of prior art closing mechanisms. The closing operation performed by the operator is a simple one-stroke operation which carries out both the spring-charging and the closing operation simultaneously. The design of my mechanism is such that it requires fewer parts than closing mechanisms of the prior art, thereby lending itself to simplicity and speed in its manufacture. The design also permits the closing mechanism to be confined in a smaller region of the circuit breaker than closing mechanisms of the prior art.

The closing mechanism of my invention may also be utilized as an alternative means for closing the circuit breaker, thereby providing a local closing means which may be relied upon in the event that the motor-driven closing means cannot be successfully actuated.

The device of my invention comprises a closing spring which is operatively connected between a toggle mechanism and a manually operable operating handle. The toggle mechanism is pivotally connected to the movable arm of the circuit breaker. When the toggle mechanism is in its collapsed state, the movable contact is driven out of engagement with the stationary contact. The closing spring is arrangedso that the de-energization of the spring from its fully charged state drives the toggle mechanism to its fully extended position, thereby driving the movable contact into engagement with the stationary contact of the circuit breaker. A prop latch which is operatively connected between the toggle mechanism and the operating handle is so arranged that the closing spring is moved to its charged state prior to the movement of the toggle mechanism. At a given instant, the closing spring achieves its fully charged state, and simultaneously therewith, the prop latch is released under the control of the operating handle to permit the closing spring to drive the toggle mechanism to its extended state, thereby causing engagement of the circuit breaker cooperating contacts.

The prop latch, in cooperation with a lost-motion linkage, prevents the occurrence of any pumping action, thereby preventing any welding elfect between the circuit breaker cooperating contacts if an arc is formed during the closing operation.

Buffer means connected to the toggle linkage is arranged so that the high speed manually actuated closing operation is unimpeded by the buffer means whereas the resetting operation of the high speed magnetic trip means of the circuit breaker is severely impeded in order to absorb the impact of the resetting force thereby preventing the magnetic trip means from being damaged.

It is, therefore, one object of my invention to provide a novel manually operable closing mechanism for a circuit breaker.

Another object of my invention is to provide a novel manually operable closing mechanism for a circuit breaker which is so arranged as to prevent any pumping action during the closing operation.

Another object of my invention is to provide a novel manually operable closing mechanism for a circuit breakor in which the closing stroke simultaneously charges the closing spring and restrains the toggle mechanism from being driven to its extended state until the closing spring is fully charged.

Another object of my invention is to provide a high speed manually actuated closing mechanism for a circuit breaker having a magnetic trip means in which the closing mechanism includes novel unilateral bufiing means for permitting the closing operation to be performed without any interference and for severely impeding the resetting operation of the magnetic trip means to prevent the trip means from being damaged even after repeated use.

Still another object of my invention is to provide a novel closing mechanism for a circuit breaker which is arranged so that it occupies a minimum amount of space in the circuit breaker.

Another object of my invention is to provide a novel closing mechanism for a circuit breaker which is simple in design and has a minimum of moving parts.

These and other objects of my invention will become apparent from the following description when taken in connection with the drawings, in which:

FIGURE 1 is a side plan view of a circuit breaker which is to be operated by my novel closing arrangement.

FIGURES 2 and 3 show the circuit breaker of FIG- URE l in the tripped open and reset positions, respectively.

FIGURE 4 is a side plan view of the novel closing mechanism showing the closing mechanism in greater detail.

FIGURE 5 shows the position of the closing mechanism of FIGURE 4 immediately after the closing operation.

FIGURE 6 is a top view of the closing mechanism shown in FIGURES 4 and 5.

FIGURE 7 is a top view partially cross-sectioned showing the flap valve means of FIGURE 6 in greater detail.

Referring now to the drawings, FIGURES 1 through 3 illustrate schematically the circuit breaker 1t) which is fully described in US. Patent Number 2,939,930, entitled Motor Closing Mechanism for Circuit Breaker, issued June 7, 1960 to CI. Clausing et al. and assigned to the same assignee as the instant invention. Since this circuit breaker mechanism merely serves as a setting for the invention of this application, the following description of the mechanism sets forth only brieiiy the operation.

In FIGURE 1, the circuit breaker 16 (shown in the closed position) has a movable contact 11a which is in engagement with a stationary contact 12. Spring 13 exerts a direct opening force on movable contact 11a, urging it towards disengagement through connecting link 13a, causing movable bridge 11 to be urged clockwise about pivot 11]). Circuit breaker 11), however, is held closed against the force of spring 13 by the magnetic latch comprising armature 14 which is drawn to the magnet 15 by a flux generated by polarizing coil 16. The magnetic structure 15 which is otherwise free to pivot about point 1'7, is restrained from rotation about point 17 by the overcenter toggle which is comprised of

links

18 and 19. A pin 20 which connects

links

18 and 19 bears against stop 21 preventing the collapse of the overcenter toggle. I

The position of the

overcenter toggle

18, 19 is maintained by the clockwise component of force which is produced by the opening spring 13 and transmitted through the armature 14 which is drawn to the magnetic structure 15.

The magnetic structure 15 is designed to cause cooperating contacts 12 and 11a to separate upon the occurrence of reverse current flow in the circuit being protected. Polarizing coil 16 generates a magnetic flux through magnetic structure 15, the flux lines being in the counterclockwise direction, as shown by phantom line 15a. A bucking bar 22 which is threaded through aperture 151) of magnetic structure 15, sets up a magnetic flux pattern, the direction of which is the same as the flux pattern set up by polarizing coil 16. The combined flux pattern has a magnitude which is sufficient to draw armature 14 against magnetic structure 15, thereby overcoming the force of opening spring 13. Bucking bar 22 is electrically connected in serial fashion to the circuit being protected, thereby causing bucking bar 22 to draw current when cooperating contacts 12 and 11a are in the engaged position. The direction of current flow through bucking bar 22 during normal operation is such as to produce a magnetic pattern which aids the magnetic pattern set up by polarizing coil 16.

Upon the occurrence of a current reversal in the circuit being protected, the flux pattern generated by bucking bar 22 is such as to oppose the flux pattern generated by polarizing coil 16, resulting in a reduction of the flux through armature 14 causing a shifting of the flux path through airgap 23 into the alternate path 150 of magnetic structure 15. The armature 14, which is no longer restrained by magnetic structure 15 is urged into clockwise rotation about pivot 17 under the influence of opening spring 13. Simultaneously therewith the force of spring 13 is removed from

toggles

18 and 19. Immediately after breaker contacts 11a and 12 open, spring 25 acts on link 18 causing it to rotate counterclockwise about pivot 26 resulting in the collapse of

toggles

18 and 19. The collapse of toggles 18 and 1h causes magnetic structure 15 to be pivoted clockwise about pivot 17.

At this instant, since cooperating contacts 11:: and 12 are in the disengaged position, as shown in FIGURE 2, current no longer flows through bucking bar 22. The field previously set up by current flow through bucldng bar 22 collapses, permitting the field generated by polarizing coil 16 to return to the path shown by phantom line 15a, causing armature 14 to be drawn towards magnetic structure 15. The circuit breaker 10 is then ready to be operated towards the closed position (as shown in FIGURE 3) by means of the closing mechanism which will be more fully described.

Cooperating contacts 12 and 11a are driven to the engaged position by closing spring 30 which drives the toggle links 18 and 19 from the collapsed position (see FIG- URE 3) to the extended position (see FIGURE 1). Closing spring 30 is charged by the closing mechanism (not shown) which moves the spring 30 in the direction shown by arrow 36a (see FIGURE 1). During the time spring Sit-is being charged, a prop latch 54 restrains movement of the toggle links '18 and 19. At the instant closing spring 30 is fully charged, prop latch 54 is moved out of engagement from pin 20 connecting

toggle links

13 and 19, causing toggle links 18 and 19 to move to the extended position under the influence of energized closing spring 319, as shown in FIGURE 1.

The closing mechanism, as shown in FIGURES 4 through 6, consists of an operating handle 42 which is pivotally mounted to housing 10a of circuit breaker 10 by pivot pin 43. Roller 44 is pivotally mounted to the lower end of operating handle 42. Driving member 45, which charges springs 34 in response to movement of operating handle 42, is pivotally mounted by pin 46a to a member 59 of the circuit breaker 10 superstructure. Cam-like edge 45a. of driving member 45 abuts against roller 44. The clockwise rotation of operating handle 42 causes roller 44 to move along cam-like edge 45a, causing driving member 45 to rotate counterclockwise about pivot pin 46a. Bracket 32 is pivotally connected to driving member 45 by pin 18. Bracket 32 has a pair of slots 32a disposed on opposite sides thereof for locking engagement with spring 36. The opposite end of spring 3t is engaged by slots 31a of bracket 31 which is similar in purpose and design to bracket 32. Bracket 31 is pivotally connected to toggle link 18 by a pin 24.

Brackets

31 and 32 are retained on pins 24 and 28 respectively by cotter pins 24b and 4 9, respectively. A roller 24a. is pivotally mounted on pin 24 which is secured to toggle links 16 (see FIGURE 6.) Toggle link 18 is pivotally mounted to shaft 26. Cylinder 26a (see FIGURE 6) surrounds one end of shaft 26 and is fixedly secured thereto so that any motion of shaft 26 is imparted to cylinder 26a. Connecting link 33 is fixedly secured to cylinder 26a at its upper end, and is pivotally connected at its lower end to rod 35 by pin 34. Rod 35 is mounted to cooperate with a piston means 36 to form a dash-pot for cushioning the resetting operation of the magnetic circuit 15 as will be more fully described. Piston 36 is mounted for longitudinal movement in casing 37a, which is enclosed on opposite ends by

covers

37 and 38. Cover 37 has an aperture 37b through which rod 35 is inserted to prevent any movement of rod 35, other than lengthwise movement in casing 37a. Covers 3'7 and 38 are secured to casing 37a by fastening means 3%, it? and 41.

A gasket 36:: is mounted in the groove 36b of piston 36 so that piston 36 engages the inner surface 371'; of casing 37a. A pair of air vents 71 are provided in cover 37. Air vents 76, which are of the same size as air vents 71, are provided in cover 3% A third air vent in cover is formed by narrow apertures 72 and 73 which are at right angles to each other. A screw 74 is threadedly engaged by aperture 75 in cover 38 which acts as an adjusting valve for the dash-pot to control the speed at which piston 36 moves as will be more fully described.

A flap valve 76 is mounted to the inner surface of cover 33 by screws 77. Flap valve 76 consists of a flat central portion 78 and resilient arms '79. The unilateral valve action performed by air vents 76 and flap valve 76 acts to impede rapid movement of piston 36 in the righthand direction and to permit rapid movement of piston 36 in the left-hand direction in a manner to be more fully described.

Spring 25 (see FIGURE 6) which surrounds shaft 26 serves to rapidly urge toggle links 18 and 19 towards their collapsed position during the tripping operation as described above with reference to FIGURES 1 through 3. One end of spring 25 is secured in any suitable manner to. lower link 18. The other end 25a of spring 25 abuts pin 25b which is inserted through the aperture 26b in shaft 26.

A prop latch 54 is pivotally mounted to members 59 by pivot means 58 (see FIGURES 4 and 6). The lefthand edge 54b of prop latch 54 abuts against roller 24a, preventing the movement of

toggle links

18 and 19, while springs 30 are being charged, as will be more fully described. Connecting link St) is pivotally mounted to prop latch 54 by pin 53 which engages an aperture 54a in prop latch 54. The opposite end of connecting link 50 has a slot 51 which cooperates with a pin 52 mounted to driving member 45 to form a lost-motion linkage. Spring 56 which is connected at one end to an aperture 55 in prop latch 54, and at the other end to an eyelet 57 in threaded member 60, is arranged to urge prop latch 54 to pivot in the clockwise direction about pin 53. Connecting link 47 is pivotally connected at one end to pin 44a upon'which roller 44 is mounted. The opposite end of connecting link 47 has an elongated slot 47a through which pin 46a is inserted, forming a lost-motion linkage. Connecting link 47 serves to limit the rotation of operating handle 42, as will be more fully described.

The closing operation of the closing mechanism is as follows: When circuit breaker It) has been tripped due to a fault current condition, the

toggle mechanism

18, 19 assumes the position shown in FIGURE 4 immediately after the tripping operation. When the fault condition has been cleared, the circuit breaker 10 may now be closed under control of the closing mechanism. To initiate the closing operation, the operating handle 42 is rotated clockwise about pivot 43 as shown by arrow 42a. This causes roller 44 to urge driving member 45 counterclockwise about pivot pin 46a. The rotation of driving member 45 causes bracket member 32, which is pivotally connected to driving member 45 by pin 48, to be moved to the right (see FIGURE 5). The movement of bracket 32 causes spring 30 and bracket 31 to be moved towards the right. Toggle link 18 which is pivotally connected to bracket 31 by pin 24 is urged in the clockwise direction about shaft 26 in response to the movement of bracket32, spring 30 and bracket 31.

The movement of toggle link 18, however, is almost immediately restrained due to the engagement of roller 24a with the edge 54]) of prop latch 54. The restraining force which prop latch 54 exerts against roller 24a causes toggle link 18 and bracket 31 to remain stationary while bracket 32 is permitted to move towards the right, thereby causing spring 30 to be expanded.

As operating handle 42 is rotated still further in the clockwise direction, pin 52, which is secured to to driving member 45, is rotated counterclockwise about pivot pin 46a causing pin 52 to move towards the right with respect to slot 51 in connecting link 50.

Prop latch 54, however, will not be urged to rotate about pin 58 due to the forces exerted by spring 56 and spring 30. Prop latch 54, therefore, remains stationary, while springs 30 are moved still further towards the fully charged position.

Further clockwise rotation of operating handle 42 causes pin 52 to abut against the right-hand edge 51a of slot 51 in connecting link 5%}. Further counterclockwise rotation of pin 52 causes connecting link 50 to be moved towards the right, thereby driving prop latch 54 counterclockwise about pivot pin 58. At this instant, closing spring 30 is almost fully charged.

After a predetermined time, edge 54 is moved completely out of engagement with roller 24a n toggle link 18 (see FIGURE This releases the restraining force imparting to spring 30 by bracket 31, causing bracket 31 to be moved to the right towards bracket 32 under control of energized spring 30. The movement of bracket 31 towards the right causes linking member 18 to be rotated clockwise about shaft 26, thereby driving linking

members

18 and 19 towards their extended position, as shown in FIGURE 5. The extension of

toggle links

18 and 19 drives magnetic structure 15 counterclockwise about pivot point 17 (see FIGURE 1), causing contacts 11a and 12 to move to their engaged positions. The dash-pot structure which is comprised of rod 35, piston 36, causing 37a and cover means 37 and 38 acts to cushion the resetting operation of armature 14 against magnetic member 15 which operation is caused by spring 25 (see FIGURE 3).

The operation of the dash-pot structure is as follows:

At the instant that circuit breaker ltl is in the position shown in FIGURE 2, spring 25 urges toggle links 18 and 19 to assume the positions shown in FIGURE 3. The driving force exerted by spring 25, however, will cause armature 14 to engage magnetic member 15 with a severe impact. The dash-pot structure acts to cushion this impact.

Link 33 is rotated counter-clockwise simultaneously with the rotation of

toggle links

18 and 19 causing rod 35 to be driven to the ri ht (see FIGURE 3). The air which is captured in the region bounded by piston 36 casing 37a and cover 38 is compressed due to the right-hand movement of piston 36. The compressed air exerts pressure on the resilient arms 79 of flap valve 76 driving them from their rest position shown by phantom lines 79 into engagement with air vents 70, thus preventing any air from escaping from the dash-pot structure through air vents 70. The air vent formed by narrow apertures 72 and 73 permit a sufficient amount of air to escape from the dash-pot structure so that the right-hand movement of piston 36 is not completely impeded. Adjusting valve 74 may be adjusted to regulate the movement of the piston 36 so that the resetting operation of armature 14 and magnetic member 15 is performed at a rapid rate but not so rapid as to cause damage to either the armature 14 or the magnetic member 15.

During the manual closing operation, air vents 71 are large enough to permit rapid left-hand movement of piston 36. Resilient arms 79 of flap valve 76 spring back to their rest position permitting air to enter through vents 70 so that a vacuum will not be formed in the region to the right of piston 36 which would impede the left-hand movement of piston 36.

Connecting link 47 causes slot 47ato move to the right with respect to pin 46a when the left-hand edge 47b of slot 47:: abuts against pin 46,. Further clockwise rotation of operating handle 42 is inhibited, thereby preventing roller 44 from being moved out of engagement with cam-like edge 45a of driving member 45.

Springs 30 become fully discharged as soon as

links

18 and 15 move to the right of center line 70 (see FIG- URE 4). Therefore, if an arc is drawn between contacts and 12 during the closing operation, no pumping elfect will be created since the closing springs 30 are now fully discharged and cannot exert any closing force against

toggle links

18 and 19.

When circuit breaker It) is tripped in response to a fault current condition thereby driving

toggle links

18 and 19 to the position shown in FIGURES 3 and 4, prop latch 54 is urged in the clockwise direction about pin 58 under the control of spring 56, thereby placing prop latch 54 in proper position for the next manual closing operation.

The simplicity of my manual closing mechanism permits its use as an alternative means for closing a circuit breaker in combination wtih an electrically motor-driven closing means, since my closing mechanism requires so little space in the circuit breaker housing. This arrangement would permit the circuit breaker to be electrically operated to the closed position from a remote location, and also would permit the closing operation to be initiated manually if, for any reason, the electrical source for the motor-driven closing means is inoperative or has failed.

It can be seen from the foregoing that I have provided a manual closing mechanism for a circuit breaker which has a minimum of moving parts, and which occupies very little space in the circuit breaker housing. It is further arranged so that the closing force on the circuit reaker contacts is completely independent of the rate at which the closing springs are charged, and in which a pumping eifect during the closing operation is completely avoided.

Although I have here described preferred embodiments of my novel invention, many variations and modifications will now be apparent to those skilled in the art, and I, therefore, prefer to be limited not by the specific disclosure herein but only by the appending claims.

I claim:

1. In combination, a pair of cooperating contacts, movable toggle means operatively connected to one of said contacts for moving said contacts between an engaged and a disengaged position, manually operable charging means, spring means connected between said charging means and said toggle means, latch means operatively connected to said charging means, said latch means being adapted to restrain movement of said toggle means during the charging operation of said spring means under control of said charging means a first end of said spring means being connected to a first end of said Charging means; the second end of said spring means being connected to an intermediate point of said toggle means; said charging means first end moving during the manual operation of said manually operable charging means to charge said spring means; said toggle means intermediate point moving to discharge said spring means for moving said cooperating contacts to the engaged position.

2. In combination, a pair of cooperating contacts, movable toggle means operatively connected to one of said contacts for moving said contacts between an engaged and a disengaged position, manually operable charging means, spring means connected between said charging means and said toggle means, latch means operatively connected to said charging means, said latch means being adapted to restrain movement of said toggle means during the charging operation of said spring means under control of said charging means, means connected to said latch means to release said latch means from said toggle means enabling said spring means to move said toggle means thereby engaging said cooperating contacts a first end of said spring means being connected to a first end of said charging means; the second end of said spring means being connected to an intermediate point of said toggle means; said charging means first end moving during the manual operation of said manually operable charging means to charge said spring means; said toggle means intermediate point moving to discharge said spring means for moving said cooperating contacts to the engaged position.

3. In combination, a pair of cooperating contacts movable between an engaged and a disengaged position, toggle means movable between an extended and a collapsed position operatively connected to said cooperating contacts, manual charging means, cam means abutting said charging means, spring means mounted between said toggle means and said cam means, said spring means being adapted to move said toggle means to said extended position in response to actuation of said charging means, latch means abutting said toggle means to retain said toggle means in said collapsed position during the charging operation of said spring means, releasing means connected between said latch means and said cam means for moving said latch means out of engagement with said toggle means, said releasing means including a lost motion mechanism to release said latch means from said toggle means when said closing spring means is fully charged.

4. In combination, a pair of cooperating contacts, one of said contacts being pivotally mounted, collapsible toggle means operatively connected to said pivotally mounted Contact for urging said cooperating contacts into and out of engagement, pivotally mounted handle means, cam means abutting said handle means and adapted to rotate in response to movement of said handle means, spring means secured between said toggle means and said cam means for urging said toggle means towards an extended position in response to movement of said cam means, latch means abutting said toggle means for preventing movement of said toggle means towards said extended position, releasing means connected between said latch means and said cam means for moving said latch means out of engagement with said toggle means to permit said toggle means to move to said extended position under control of said spring means.

5. In combination, a pair of cooperating contacts, one of said contacts being pivotally mounted, collapsible toggle means operatively connected to said pivotally mounted contact for urging said cooperating contacts into and out of engagement, pivotally mounted handle means, cam means abutting said handle means and adapted to rotate in response to movement of said handle means, spring means secured between said toggle means and said cam means for urging said toggle means toward an extended position in response to movement of said cam means, latch means abutting said toggle means for preventing movement of said toggle means towards said extended position, releasing means connected between said latch means and said cam means for moving said latch means out of engagement with said toggle means to permit said toggle means to move to said extended position under control of said spring means, said releasing means including a lost motion mechanism for releasing said latch means at the instant said spring means is fully charged.

6. In combination, a pair of cooperating contacts, one of said contacts being pivot-ally mounted, collapsible toggle means operatively connected to said pivotally mounted contact for urging said cooperating contacts into and out of engagement, pivotally mounted handle means, cam means abutting s aid handle means and being adopted to rotate in response to movement of said handle means, spring means secured between said toggle means and said cam means for urging said toggle means towards an ex tended position in response to movement of said cam means, latch means abutting said toggle means for preventing movement of said toggle means towards said extended position, releasing means connected between said latch means and said cam means for moving said latch means out of engagement with said toggle means to permit said toggle means to move to said extended position under control of said spring means, said releasing means including a lost motion mechanism for releasing said latch means at the instant said spring means is fully charged, butler means connected to said toggle means for absorbing some of the impact of the closing force exerted by said spring means.

7. In combination, a pair of cooperating contacts, one of said contacts being pivotally mounted, collapsible toggle means operatively connected to said pivotally mounted contact for urging said cooperating contacts into and out of engagement, pivotally mounted handle means, cam means abutting said handle means and adapted to rotate in response to movement of said handle means, spring means secured between said toggle means and said cam means for urging said toggle means towards an extended position in response to movement of said cam means, latch means abutting said toggle means for preventing movement of said toggle means towards said extended position, releasing means connected between said latch means and said cam means for moving said latch means out of engament with said toggle means to permit said toggle means to move to said extended position under control of said spring means, said releasing means including a lost motion iii mechanism for releasing said latch means at the instant said spring means is fully charged, butter means connected to said toggle means for absorbing some of the impact of the closing force exerted by said spring means, said buffer means comprising a cylinder, a piston mounted in said cylinder and a rod connected between said piston and said toggle means.

8. In combination, a pair of cooperating contacts, one of said contacts being pivotally mounted, collapsible toggle means operatively connected to said pivotally mounted contact for urging said cooperating contacts into and out of engagement, pivotally mounted handle means, cam means abutting said handle means and adapted to rotate in response to movement of said handle means, spring means secured between said toggle means and said cam means for urging said toggle means towards an extended position in response to movement of said cam means, latch means abutting said toggle means for preventing movement of said toggle means towards said extended position, releasing means connected between said latch means and said cam means for moving said latch means out of engagement with said toggle means to permit said toggle means to move to said extended position under control of said spring means, said releasing means includ ing a lost motion mechanism for releasing said latch means at the instant said spring means is fully charged, butter means connected to said toggle means for absorbing some of the impact of the closing force exerted by said spring means, said butter means comprising a cylinder, a piston mounted in said cylinder and a rod connected between said piston and said toggle means, reset means connected to said latch means for moving said latch means towards engagement with said toggle means when said cooperating contacts are disengaged to enable said charging means to energize said closing spring.

9. In combination, a pair of cooperating contacts, one of said contacts being pivotally mounted, collapsible toggle means operatively connected to said pivotally mounted contact for urging said cooperating contacts into and out of engagement, pivotally mounted handle means, cam means abutting said handle means and adapted to rotate in response to movement of said handle means, closing spring means secured between said toggle means and said cam means for urging said toggle means towards an extended position in response to movement of said cam means, second spring means operatively connected to said toggle means to urge said toggle means towards said collapsed position in response to the disengaging of said cooperating contacts, latch means abutting said toggle means towards extended position, releasing means connected between said latch means and said cam means for moving said latch means out of engagement with said toggle means to permit said toggle means to move to said extended position under control of said spring means, the closing force of said closing spring means being greater than the opening force of said second spring means.

10. In combination, a pair of cooperating contacts, high speed magnetic trip means for moving said contacts to a disengaged portion in response to a fault current condition, toggle means connected to said trip means for automatically resetting said trip means upon completion of said trip operation, buffer means connected to said toggle means for reducing the impact of the resetting operation upon said magnetic trip means to prevent damage to said trip means; manually operable high speed closing means; closing spring means connected between said closing means and said toggle means.

11. In combination, a pair of cooperating contacts, high speed magnetic trip means for moving said contacts to a disengaged position in response to a fault current condilit) tion, toggle means connected to said trip means for automatically resetting said trip means upon completion of said trip operation, buffer means connected to said toggle means for reducing the impact of the resetting operation upon said magnetic trip means to prevent damage to said trip means, closing spring means connected to said toggle means, high speed manually operable closing means operatively connected to said closing spring means for moving said cooperating contacts towards engagement.

12. in combination, a pair of cooperating contacts, high speed magnetic trip means for moving said contacts to a disengaged position in response to a fault current condition, toggle means connected to said trip means for automatically resetting said trip means upon completion of said trip operation, butler means connected to said toggle means for reducing the impact of the resetting operation upon said magnetic trip means to prevent damage to said trip means, closing spring means connected to said toggle means, high speed manually operable closing means operatively connected to said closing spring means for moving said cooperating contacts towards en agement, said buffer means including means to prevent said butter means from interfering with the high speed operation of said closing means.

13. in combination, a pair of cooperating contacts, high speed magnetic trip means operatively connected to said cooperating contacts for moving said contacts towards a disengaged position, toggle means connected to said trip means for automatically resetting said trip means upon completion of the trip operation, closing spring means connected to said toggle means, high speed manually actuated ciosing means connected to said closing spring means for moving said cooperating contact-s towards an engaged position upon completion of said trip operation, unilateral buffer means connected to said toggle means for absorbing the impact of said resetting operation to prevent damage to said magnetic trip means while permitting said closing means to operate at high speed.

14. in combination, a pair of cooperating contacts, high speed magnetic trip means operatively connected to said cooperating contacts for moving said contacts towards a disengaged position, toggle means connected to said trip means for automatically resetting said trip means upon completion of the trip operation, closing spring means connected to said toggle means, high speed manually actuated closing means connected to said closing spring means for moving said cooperating contacts towards an engaged position upon completion of said trip operation, unilateral bufier means connected to said toggle means for absorbmg the impact of said resetting operation to prevent damage to said magnetic trip means while permitting said closing means to operate at high speed, said butter means including a cylinder, a piston mounted in said cylinder and valve means for severely impeding the movement of said piston in a first direction and for permitting high speed movement of said piston in a direction opposite said first direction.

References Cited in the file of this patent UNITED STATES PATENTS 826,248 Hewlett July 17, 1906 1,310,380 Wl'littingl'iam July 15, 1919 2,625,781 Scott Dec. 31, 1935 2,145,140 Starr Ian. 24, 1939 2,866,872 Turner Dec. 30, 1958 FOREIGN PATENTS 740,361 Great Britain Nov. 9, 1955