US2036284A - Circuit breaker for network protectors - Google Patents

Description

April 7, 1936. T LlNDSTROM 2,036,284

CIRCUIT BREAKER FOR NETWORK PROTECTORS April 7, 1936. T. LINDsTRoM CIRCUIT BREAKER FOR NETWORK PROTECTORS Filed Sept. 18, 1954 2 Sheets-Sheet 2 lNvENToR ,TZ/7'@ BY I Patented Apr. 7, 1936 UNITED STATES CIRCUIT BREAKEB FOR NETWORK PROTECTORS Ture Lindstrom, Edgewood, Pa., assignor to Westinghouse Electric & Manufacturing Company,

East Pittsburgh, Pa.,

sylvania a corporation of Penn- Application September 18, 1934, Serial No. 744,566

16 Claims.

My invention relates to circuit breakers, and particularly to improved apparatus for actuating circuit breakers.

The object of my invention is to provide a latching mechanism for circuit breakers, the members of which are not actuated during the closing movement of the breaker.

Another object of my invention is to provide a latching mechanism for circuit breakers, the members of which are not actuated during the closing movement of the breaker and which cooperate to present a fixed pivot point remote from the latch about which the actuating arm of the breaker will swing during the closing movement of the breaker.

A further object of my invention is to provide a circuit breaker which has a strong means to initially bias the contact members to open posi- 'tion upon a tripping movement of the latching mechanism and a weaker means to continue the opening movement of the actuating arm after the initial means has been removed so as to get a positive opening of the contact members before the latching mechanism is automatically re- 25 turned to latched position,

A still further object of my invention is to provide a circuit breaker with a movable contact member which is movable in all directions so as to remove all strain from the connecting mem- 30 bers during an opening movement of the breaker.

The invention accordingly, is disclosed in the embodiment thereof shown in the accompanying drawings, and comprises the features of construction, combination of elements and arrange- 35 ment of parts which will be exemplified in the construction hereinafter set forth, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference may be had to the following detailed description, taken in conjunction with the accompanying drawings in which:

Figure 1 is a view, partly in side elevation and 45 partly in section, of a circuit breaker constructed in accordance with this invention;

Fig. 2 is an enlarged view in section taken along line II-II of Fig. 1;

Fig. 3 is a view in section taken along the line 50 III-III of Fig. 2; and,

Fig. 4 is an enlarged view in sectiontaken along the line IV-IV of Fig. 1.

As illustrated in Figs. 1, 2 and.3, the toggle linkage, tripping,'and latching mechanism for 55' only one pair of cooperative contact members is (Cl. o-89) shown. However, as shown ln Fig. 4 and hereinafter described, by invention is applicable to circuit breakers having a plurality of poles, each pole having one or more pairs of cooperative contact members. 5

Referring to the drawings and Fig. 1, in particular, a pair of cooperative switch members I and 2 are shown in engagement, the switch member 2 is carried by an actuating arm 3 pivoted on a bracket t at a point 5. The bracket 4 may be mounted on the switchboard 6 or other suitable support.

In mounting the switch member 2, a connecting eye member l having an upwardly curved end 8 is slidably mounted in'an opening S in the upper end of the actuating arm 3. The contact member 2 is pivotally mounted on the end 8 of the eye member by means of a pin I il. When the contact member 2 is mounted in this manner, lt may be oscillated through a predetermined angle about the pin l0. In order to maintain good contact pressure between the contact members I and 2, a biasing spring Il is carried by the eye member 'I' and is disposed between the actuating arm and contact member 2 to exert a force on the contact members while the actuating arm is in the closed position. The eye member l is provided with a nut l2 'having a curved surface I3 which is disposed to engage a grooved seat I4 on the actuating arm 3 allowing the eye member and the contact member 2 mounted thereon to move in the direction of least resistance during an lopening movement of the breaker.

In order to conduct the current to the contact member 2 without conducting it through the pivot point 5 of the actuating arm 3, a laminated conductor I5 is provided between the bracket 4 and the contact member 2. Notches are provided in bracket 4 and the contact member 2 to receive the opposite ends of the laminated conductor I5.

In breakers of this type, heavy currents are conducted and it sometimes happens that the cooperative contact members are welded together. In order to break apart the cooperative contact members I and 2 during a switching operation, a tail piece I6 is provided on the contact member 2 and when the contact members are in engagement it seats against the pin I1 provided on the actuating arm 3.

As shown, a flat spring I8 is provided for blasing the actuating arm 3 clockwise about its pivot point 5 to effect a separation of the cooperative contact members I and 2. The spring I8 is connected to the bracket 4 at a point I9 and is in 55 engagement with the pin I 1, thus exerting a biasing force on the actuating arm 3 when the contact members I and 2 are in engagement. Therefore, when the switch is tripped, the spring biases the actuating arm 3 clockwise about its pivot point and the pin I1 exerts a leverage action to the tail piece I8 o1' the contact member 2, which will tend to roll it on and break it loose from the contact member I ii' they should be welded. v

As shown, the eye member 1 permits the actuating arm 3 to move a predetermined distance relative to the contact member 2 during a tripping movement oi' the breaker. The springs II and I8 ,are thus exerting a strong force and bias the actuating arm 3 to an open position while the cooperative contact members are still in engagement. During this initial movement of the actuating arm towards an open position, the pin I1 engages-the tail piece I6 oi.' contact member 2 exerting a force thereon to turn the contact member 2 about its pivot pin III, rolling the contact member 2 on contact I and freeing all welds therebetween.

The conductor I5, although built oi' iiexible laminated copper plates, is yet so stiff that there will be a considerable strain set up within the laminations when contact member 2 is turned about its pivot pin I0 and rolled on contact member I to eect the breaking of the welds therebetween. To reduce this strain, contact member 2 is mounted on eye member 1 and the actuating arm 3 as hereinbefore described, with the nut I2 of the eye member 1 seating in grooved seat I4 in a universal joint relation and allowing the eye member 1 to move in the direction of least resistance. This direction of movement of eye member 1 and. contact member 2 will tend to keep the contact member 2 parallel with conductor I5 and will reduce the strain in the conductor to a minimum value.

An arcing member 2| is provided on the switch actuating arm 3 and is connected to contact member 2 by a flexible shunt 20. Arcing member 2I is disposed to engage arcing member 22 carried by an arc shute 23, which is carried by conductor 24 mounted on the panel 6. In mounting the arcing member 2|, a bolt 25 is slidably mounted in an opening 26 in the upper end of actuating arm 3 and is attached at one end to arcing member 2| by suitable means. In order to maintain good contact pressure between the arcing members 2l and 22, a biasing spring 21 is carried by bolt 25 and is disposed between the actuating arm and arcing member 2I. A nut 28 is provided on the free end of bolt 25 and acts as a stop to limit the movement of actuating arm 3 before arcing member 2I is moved from engagement with arcing member 22, Spring 21y is a strong spring and will cooperate with spring II to initially force actuating arm 3 into open position when the breaker is tripped. Spring I8 may be a weak spring as compared to springs II and 21 but will be strong enough to cause the actuating arm 3 to continue its opening movement after the initial force of springs II and 21 have been used to Start the opening movement.

A latching mechanism and a. plurality of toggle links are provided for actuating the circuit breaker. The actuating arm 3 is pivotally connected to a toggle linkage 29 at a point 30. A stop 3l is provided on the actuating arm 3 to cooperate in breaking the toggle linkage 29 during an opening movement of the actuating arm.

In order to provide a xed pivot point about which the toggle linkage 29 may be rotated during a closing operation, I provide a latching mechanism which will stand in a latched position during the closing operation and will cooperate to present a fixed pivot point for toggle linkage 29 at a point remote from the latch.

The latching mechanism comprises a bell crank 32 pivotally connected to the toggle linkage 29 at a point 33 and disposed to engage a `connecting member or latch 34. The bell crank 32 is pivotally mounted on the frame 35 of the circuit breaker at a point 38 and is provided with a forkedV end 31. A roller 38 is pivotally mounted in the forked end of the member 32 and is disposed to engage the connecting member 34.

In order to hold the bell crank 32 in a iixed position during a closing operation of the linkage 29, the connecting member 34, which is pivotally mounted on the frame 35 at a point 33, is provided with a seat 40 disposed to receive the roller 38. A cam face 4I is provided on the connecting member 34 as a guiding surface disposed to engage the roller 38 during a tripping movement of the latching mechanism.

A biasing spring 42 is connected to the bell crank 32 at a point 43 and to the frame 35 at a point 44 for biasing the bell crank 32 in a counterclockwise direction to its locked position when the toggle linkage 29 is broken and the force exerted by springs I I, I8 and 21 has been utilized in opening the breaker.

In order to control the latching mechanism, a toggle linkage 45, pivotally mounted to the frame 35 at a point 46 and to the connecting member 34 at a point 41, is disposed to be broken during an overload on the protected circuit. The toggle linkage 45 and spring 42 cooperate with bell crank 32 and connecting member 34 to present a positive mechanical lock for the main toggle linkage 29. The toggle linkage 45 may be broken by the plunger 48 of the electromagnet 49 when the latter is energized by the current iiowing in contact members I and 2.

A forked member 50 is pivotally mounted on the switch frame 35 at a point 38 for actuating the toggle linkage 29 to a closed position. In addition to the forked member 58, an electromagnet 5I and a plunger 52 disposed in alignment with one of the actuating arms of the forked member' 50 is provided for actuating the toggle linkage 29 to its closed position. Electromagnet 5I may be suitably controlled to eii'ect the closing of the contact members.

As illustrated in Figs. 1 and 3, the circuit breaker stands closed. When the overload occurs, the electromagnet 49 is energized, actuating the plunger 48 upwardly to break the toggle linkage 45. When the toggle linkage 45 is broken, the force resulting from the pressure of compressed springs I I, I8 and 21 is transmitted through toggle linkage 29, bell crank 32 to the connecting member 34 and actuates it in a counter-clockwise direction about its pivot point 39 on the frame 35. This movement cf connecting member 34 releases the roller 38 of the bell crank 32 from its locked position in the seat 40 and the bell crank 32 rotates in a clockwise direction about its pivot point 36, the roller 38 rolling along the guiding cam face 4I of the connecting member 34 and actuating the connecting member 34 to transmit the reactive force to the toggle linkage 45. This movement of bell crank 32 moves the toggle linkage 29 to the right in an upwardly direction into engagement with the stop 3| to break the linkage 29 and separate the contact members I and 2.

The spring 42 is tensioned by the clockwise movement of the bell crank 32, and, when the toggle linkage 29 is broken and the reactive force resulting from the closed contact pressure between contact members I and 2 is released, will rotate the bell crank 32 to its latched position with the roller 38 in the seat 40 of the connecting member. 'I'he connecting member 34 and the toggle linkage 45 under the inuence of 'gravity and spring 58 as hereinafter described drop to the position illustrated in Fig. 1 and latch the bell crank 32 in a iixed position.

When the latching mechanism is employed in a circuit breaker having a plurality o poles, each pole is provided with the toggle linkages and latching mechanism as described, and is cooperatively mounted and disposed to respond to a. clockwise movement of a. cross-bar 53 about its pivot point 46, as shown in Figs. 1 and 4, mounted on the frame 35 of the circuit breaker.

A plurality of springs is provided to actuate the cross bar 53 and the toggle linkages 45 to their closed positions. A spring 54 is disposed to bias the cross bar 53 in a counter-clockwise direction as illustrated in Fig. 1 about its pivot pin 46 to engage the frame 35 ofthe circuit breaker at a point 55. Spring 54 is preferably a coil spring pivotally mounted on pin 45 with its ends disposed so that one end engages the cross bar 53 at a point 56 and the other end engages a stop 5l on the frame 35. Cross bar 53 is thus normally biased away from contact with the toggle linkages 45.

Each toggle linkage 45 is provided with a spring 58 disposed to bias the linkage 45 to its closed position, as viewed in Fig. 1. Spring 58, as illustrated in Fig. 4, is preferably a coil spring pivotally mounted on pin 46 and so disposed that the turns are equally divided on each side of toggle linkage 45 with the connecting portion of the divided coil spring in engagement with toggle linkage 45 at a point 59. The ends 6U of spring 58 are in engagement with the cross bar at point 6I. The springs 58 cooperate with cross bar 53, when held in its closed position by spring54, to force the toggle linkages 45 to their overcenter or closed position.

The tripping of any one of the toggle linkages 45 causes the reactive force resulting from the pressure between contact members I and 2 to actuate the broken linkage 45 in an upward direction as viewed in Fig. 1, and force it into engagement with cross bar 53, rotating the cross bar 53 about the pivot pin 46 in a clockwise direction. This clockwise movement of cross bar 53 will release the tension of the remaining springs 58 of the closed toggle linkages 45 and will cause the lower arm 62 of cross bar 53 to engage the toggle linkages 45 to break them and to separate their correspondingcontact members I and 2.

In order to close the circuit breaker after toggle linkage 45 and the latching mechanism have been returned to latched position, the forked member 50 is actuated either manually or electrically against the toggle linkage 29 to force it upwardly swinging about the xed pivot pin 33 to its overcenter position. It is to be noted that all of the rotational forces caused by the closing movement oitoggle linkage 29 is about the xed pivot point 33 which is at a point remote from the latch. 'Ihe remote positioning of the fixed point guards against an accidental tripping of the latch during the closing movement of the toggle linkage 29.

This movement of toggle linkage 29 actuates arm 3 to closed position, compressing springs II and 21 to bias movable contact member 2 into engagement with contact member I and arcing member 2| into engagement with its corresponding arcing member 22.

In addition tothe positioning of the xed pivot point at a point removed from the latch, this invention has a more positive opening movement of the breaker than of the breakers heretofore employed and utilizes a strong force to effect the initial opening of the breaker and a weak force to secure positive opening of the breaker. Considerable strain on the conductors is also removed by the improved anti-freeze movable contact member which is made a part of this invention.

Since certain changes may be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not inl a limiting sense.

I claim as my invention:

l. In an actuating mechanism for a. circuit breaker, in combination, a main toggle linkage. an auxiliary toggle linkage, a latching mechanism for the main toggle linkage disposed between the toggle linkages providing a positive mechanical lock, the latching mechanism being disposed for operation independently of the main toggle linkage, means for breaking the auxiliary toggle linkage, the auxiliary toggle linkage being disposed to trip the latching mechanism and to cooperate with the latching mechanism to present a iixed pivot point on which the main toggle linkage turns in closing the breaker.

2. In an actuating mechanism for a circuit breaker, in combination, a main toggle linkage, an auxiliary toggle linkage, a latching mechanism for the main toggle linkage between the toggle linkages, providing a positive mechanical lock, the latching mechanism being disposed for operation independently of the main toggle linkage, means forbreaking the auxiliary toggle linkage, the auxiliary toggle linkage being disposed to trip the latching mechanism, said latching mechanism and said auxiliary toggle linkage being disposed to return to locked position after a tripping movement to present a fixed pivot point about which the main toggle linkage turns in closing the breaker.

3. In an actuating mechanism for a circuit breaker, in combination, a main toggle linkage, an auxiliary toggle linkage, a latching mechanism for the main toggle linkage disposed between the toggle linkages providing a` positive mechanical lock, the latching mechanism being disposed for operation independently of the main toggle linkage, means for breaking the auxiliary toggle linkage, the auxiliary toggle linkage being disposed to trip the latching mechanism and to cooperate with the latching mechanism to return to their locked position immediately after a tripping movement, the latching mechanism and the auxiliary toggle linkage cooperating in said locked position to present a iixed pivot'point about which the main toggle linkage turns in closing the breaker.

4. In an actuating mechanism for a circuit breaker, in combination, a main toggle linkage, an auxiliary toggle linkage, means for breaking the auxiliary toggle linkage, a latching mechanism for the main toggle linkage disposed between the toggle linkages and disposed to be tripped when said auxiliary toggle linkage is broken and disposed for operation independently of the main toggle linkage, the latching mecha.- nism comprising a connecting member and a bell crank cooperatively engaged, the latching mechanism and the auxiliary toggle linkage cooperating to present a iixed pivot point on the bell crank about which the main toggle linkage turns in closing the breaker.

5. In an actuating mechanism for a. circuit breaker, ln combination, a main toggle linkage, an auxiliary toggle linkage, means for breaking the auxiliary toggle linkage, a latching mechanism for the main toggle linkage disposed between the toggle linkages and disposed to be tripped when the auxiliary toggle linkage isA broken, the latching mechanism comprising a connecting member and a bell crank cooperatively engaged, the latchlng mechanism and the auxillary toggle linkage cooperating to present a xed pivot point on the bell crank for the main toggle linkage to turn about in closing the breaker, said pivot point being remote from the said cooperative engagement of the connecting member and the bell crank.

6. In an actuating mechanism for a circuit breaker provided with cooperative ycontact members, in combination, a main toggle linkage for actuating the contact members into engagement, a latching mechanism secured to one end of the main toggle linkage, an auxilia'y toggle linkage secured at one end to the latching mechanism to support it in a predetermined position, the latching mechanism being disposed for operation independently of the main toggle linkage, the latching mechanism when supported by the auxiliary toggle linkage providing a positive mechanical lock and presenting a fixed pivot point about which the main toggle linkage may be turned in actuating the contact members into engagement.

'7. In an actuating mechanism for a circuit breaker provided with cooperative contact members, in combination, a main toggle linkage for actuating the contact members into engagement, a latching mechanism secured to one end of the main toggle linkage, an auxiliary toggle linkage secured at one end to the latching mechanism to support it in a predetermined position providing a positive mechanical lock, the latching mechanism when supported by the auxiliary toggle linkage presenting a fixed pivot point about which the main toggle linkage may be turned in actuating the contact members into engagement, means for tripping the auxiliary toggle linkage to release the latching mechanism and the main toggle linkage to effect the separation of the contact members, the auxiliary toggle linkage being disposed to actuate the latching mechanism to its locked position after each operation of the main toggle linkage to separate the contact members.

8. In a circuit breaker, a pair of separable contacts, a supporting member movable to open and to closed position and having one ofsaid contacts movably mounted thereon, biasing means applying a force between said supporting means and said contact mounted thereon to bias said contact into engagement with the other Contact and to bias said supporting means toward open position during the first part only of its movement to open position, means for biasing said supporting means to move to its fully open position, means for holding said supporting means in closed position including releasable means and a trip member movable from a set to a tripped position independently of the reieasable means to cause opening of the circuit breaker. means for causing the release o! said releasable means upon movement of said trip member to tripped position before said biasing means applying a force between said supporting means and the contact mounted thereon ceases to bias said supporting means toward open position and means for automatically returning said trip member from tripped to set position after the release of said releasable means.

9. In a circuit breaker, a fixed and a movable contact, a contact arm on which said movable contact is mounted, a rst spring between said movable contact and said contact arm for biasing said movable contact into engagement with said xed contact and for biasing said contact arm to open position during only the initial movement of said contact arm to open position, a second spring biasing said contact arm to move to fully open position, means for holding said contact arm in closed position including a pair oi toggle links having one end secured to a latched member releasable to cause opening of said contacts, means for causing, said toggle linkage to be broken before said first spring ceases to bias said contact arm to open position, and a spring effective to return said member to latched position after the toggle linkage has been broken.

l0. In a circuit breaker in combination, a movable contact member and a stationary contact member, the movable contact member pivotally mounted to a connecting member slidably mounted in an actuating arm, cooperative means between the slidable connecting member and the actuating arm to permit the slidable connecting member and the contact member pivotally mounted thereon to move in any direction during a movement of the actuating arm, and spring means mounted on the connecting member to bias the movable contact member into engagement with the stationary contact member during a closing movement of the breaker and to bias the actuating arm to open position during an opening movement of the breaker.

11. In a circuit breaker in combination, a movable contact member and a stationary contact member, the movable contact member pivotally mounted to a connecting member slidably mounted in an actuating arm, cooperative means between the slidable connecting member and the actuating arm to perrnlt the slidable connecting member and the contact member pivotally mounted thereon to move in any direction during a movement of the actuating arm, spring means mounted on the connecting member to bias the movable contact member into engagement with the stationary contact member during a closing movement of the breaker and to bias the actuating arm to open position during an opening movement of the breaker, and means on the actuating arm to cooperate with the movable contact member to rotate the movable contact member about its pivot point during an opening movement of the breaker.

12. In an actuating mechanism for a circuit breaker, in combination, a main toggle linkage, an auxiliary toggle linkage, means for breaking the auxiliary toggle linkage, a latchlng mechanism secured to one end of the toggle linkages and disposed to be tripped when the auxiliary toggle linkage is broken, the latching mechanism being disposed for operation independently of the main toggle linkage, meanscooperating with the auxiliary toggle linkage for returning the auxiliary toggle linkage and the latching mechanism to their locked position after a tripping movement to present a xed pivot point about which the main toggle linkage turns in closing the breaker.

13. In an actuating mechanism for a circuit breaker, in combination, a main toggle linkage, an auxiliary toggle linkage, means for breaking the auxiliary toggle linkage, a latching mechanism secured to one end of the toggle linkages and disposed to be tripped when the auxiliary toggle linkage is broken, the latching mechanism comprising a bell crank and a connecting member cooperatively engaged and disposed for operation independently of the main toggle linkage, means cooperating with the bell crank and means cooperat-ing with the auxiliary toggle linkage for returning the auxiliary toggle linkage and the latching mechanism to their locked position after a tripping movement to present a fixed pivot point about which the main toggle linkage turns in closing the breaker.

14. In an actuating mechanism for a circuit breaker, in combination, a main toggle linkage, an auxiliary toggle linkage, a latching mechanism for the main toggle linkage disposed between the toggle linkages providing a positive mechanical lock, the latching mechanism comprising a bell crank and a connecting member cooperatively engaged, the main toggle linkage having one end secured to the bell crank, the auxiliary toggle linkage having one end secured to the connecting member, means for breaking the auxiliary toggle linkage, the auxiliary toggle linkage being disposed to trip the latching mechanism independently of the operation of the main toggle linkage to release the main toggle linkage and to cooperate With the latching mechanism to return to their locked position immediately after a tripping movement, the auxiliary toggle linkage and the latching mechanism cooperating in said locked position to present a xed pivot point on the bell crank about which the main toggle linkage turns in closing the breaker.

15. In an actuating mechanism for a circuit breaker, in combination, a main toggle linkage, an auxiliary toggle linkage, a latching mechanism for the main toggle linkage disposed between the toggle linkages providing a positive mechanical lock7 the latching mechanism comprising a bell crank and a connecting member cooperatively engaged. the main toggle linkage having one end secured to the bell crank, the auxiliary toggle linkage having one end secured to the connecting member, means for breaking., the auxiliary toggle linkage, the auxiliary toggle linkage being disposed to trip the latching mechanism to release the main toggle linkage and to cooperate with the latching mechanism to return lto their locked position immediately after a tripping movement, the bell crank and the connecting member moving relative to one another during the tripping and latching movement while in cooperative slideable engagement, the auxiliary toggle linkage and the latching mechanism cooperating in said locked position to present a iixed pivot point on the bell crank about which the main toggle linkage turns in closing the breaker.

16. In a circuit breaker, in combination, a fixed and movable contact member, a contact arm on which the movable contact member is mounted, a main toggle linkage secured at one end to the contact arm for actuating the movable contact member into contact making position with the iixed contact member, a latching mechanism secured to the other end of the main toggle linkage for supporting it, an auxiliary toggle linkage secured at one end to the latching mechanism to support it in a predetermined position providing a positive mechanical lock, the latching mechanism when supported by the auxiliary toggle linkage presenting a xed pivot point about which the main toggle linkage may be turned in actuating the contact members into engagement, means for tripping the auxiliary toggle linkage to release the latching mechanism and the main toggle linkage to effect the separation of the contact members, the auxiliary toggle linkage being disposed to actuate the latching mechanism to its locked position after each operation of the main toggle linkage to separate the contact members.

TURE LINDSTROM.

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