US1915059A - Electric switch apparatus - Google Patents

Description

June 20, 1933. J. JENSEN 1,915,059

ELECTRIC SWITCH APPARATUS Filed Feb. 4, 1952 In ventov; Jens M.Jehsen,

by le His Ab'bovneg.

Patented June 20, 1933 UNITED STATES PATENT OFFICE JEN S M. JENSEN, OF LANSDOWNE, PENNSYLVANIA, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK ELECTRIC SWITCH. APPARATUS Application filed February 4, 1932. Serial No. 590,797.

My invention relates to electric switch apparatus, more particularly to means controlling the tripping mechanism of circuit breakers.

In the operation of electric motors for eX- ample, wherein rheostats and starting resistances are dispensed with, the first rush of current upon closure of the controlling switch or circuit breaker may be of such magnitude that the calibrated overload of the circuit breaker is exceeded. The breaker thereupon is tripped open causing inconvenience and delay in establishing-operating connections. Since motor armatures are generally designed to carry a heavy current for a very short period, as during the increase of motor speed to normal value, it is desirable to prevent tripping of the circuit breaker during the brief period of starting. This has heretofore been accomplished in a number of ways, one method including manual control wherein the operator holds the trip lever from tripping with one hand while operating the circuit breaker with the other hand.

The principal object of my invention is the provision of improved means for preventing tripping of a circuit breaker concurrent with the closing operation thereof.

My invention will be more fully set forth in the following description referring to the accompanying drawing, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

Referring to the drawing Fig. 1 is an elevational view, partly in section, of electric switching apparatus embodying my invention; Fig. 2 is a plan view of the apparatus shown in Fig. 1, and Fig. 3 is an elevational view showing the apparatus in the starting position.

Referring to Fig. 1, there is illustrated switch operating mechanism of the trip-free type, generally indicated at 1, coacting with tripping means 2 and operatively connected, as by the usual lift rod 3, to a circuit breaker (not shown). The circuit breaker may be of any suitable type, as an oil breaker, the specific arrangement shown functioning to close the breaker upon upward movement of the lift rod 3 and vice versa.

The operating mechanism 1 comprises a shaft 4 on which an operating arm 5 is rotatably mounted. The arm 5 is pivotally connected at 6 to the lift rod 3 and is provided with a stop portion 7 arranged to engage a fixed stop 8 in a manner hereinafter described. As the arm 5 is not keyed to the shaft 4, there is provided means for rigidly connecting the shaft 4 with respect to the arm 5 during the switch closing operation. This may comprise any well known trip-free arrangement as an intermediate lever 9 like wise freely mounted for rotation on the shaft 4 and a tripping toggle interconnecting the levers 5 and 9. As best shown in Figs. 1 and 3, the toggle comprises a link 10 connected at 11 to the intermediate link 9 and a coacting link 12 joined to the link 10 at 13 and connected at 14 to a portion 15 forming part of the arm 5.

The arm 5 is normally biased clockwise or towards open circuit position as by a coil spring mounted on the shaft 4, one end of the spring 16 engaging the arm 5 and the other end 17 engaging the stop member 8. For the purpose of holding the toggle 104-12 in thrust transmitting position a latch 18 pivotally carried at 19 by the toggle link 12 is arranged to engage a shoulder 20 of the toggle link 10 as best shownin Fig. 3.

The usual overload tripping device may comprise a solenoid 21 having a movable core 22 arranged to be drawn upwardly into the coil upon predetermined energization thereof and strike the tripping lever 23, causing it to move upwardly about its pivotal mounting 24 (Fig. 2). The lever 23 is provided with an oflset portion 25 normally positioned beneath the extension or tail of the latch 18 when the mechanism is in the closed circuit position shown in Fig. 3. Hence actuation of the tripping device is effective to move the latch 18 clockwise causing collapse of the toggle 10-12 and release of the connection between the levers 5 and 9.

The actuating means for the operating mechanism may comprise a manually controlled lever or crank 26 having a hub portion 27 which is keyed to the shaft 4 and provided with an offset lug 28 arranged to engage the intermediate lever 9. lVhen the toggle 10-12 is latched and the operating mechanism is in the open circuit position, as shown in Fig. 1, counter-clockwise rotation of the crank 26 causes a corresponding rotation of the intermediate lever 9. The switch is accordingly closed through the thrust transmitting toggle 1012 which in effect locks the levers 5 and 9 together during the closing operation. After predetermined rotation of the crank 26 the switch is closed and further movement of the crank is prevented by a portion 29 forming part of the intermediate link 9 engaging the stop member 8. hen in this position the breaker is maintained closed by the underset position of the toggle 1012. In other words, the force of the opening spring acting on the arm 5 simply tends to urge the lever 9 more firmly into engagement with the stop 8, opening of the switch being effected only when the latch 18 H is tripped causing collapse of the toggle 1012 and release of the arm 5.

The structure so far described may vary considerably in detail since it comprises merely a constructional example of an operating mechanism suitable for use in connection with the present invention.

For the purpose of preventing tripping of the latch with the closing operation of the breaker there is provided a connection between the operating mechanism and the trip ping device arranged to restrain actuation of the tripping lever when the starting handle is thrown over to close the circuit breaker. To this end there is rigidly mounted on the shaft 4 a member 30 arranged to receive and guide an extension pin 31 of a telescopic member 32. The member 32 is hollow and open at one end, as shown in Fig. 1, and is likewise guided for longitudinal movement at its open end as by a plunger 33 pivotally mounted at 34, the plunger and telescopic member being biased apart as by a spring 35 contained within the telescopic member.

Carried by the member 32 is an offset portion 36 arranged, when in a predetermined position. to extend directly over a portion 37 forming part of the trip lever 23. The relative vertical position of the members 36 and 37 is maintained by a pin and slot connection 38 between the guide plunger 33 and the member 32. As clearly illustrated in Figs. 1 and 2, the trip lever 23 is free to func tion in its usual manner when the operating crank 26 is in its normal lower or neutral position. This position is assumed after closing of the breaker since the keyed member 28 is free to be moved out of engagement with lever 9 and clockwise back to the initial position under the influence of a suitable biasing force.

During the starting period, however, when the crank 26 is rotated clockwise to the po sition shown in Fig. 3 the telescopic member 32 is moved by the member 30 upon the guide plunger 33 against the bias of spring 35 so that the looking out lug 36 is directly over the portion 37 of the trip lever, thereby preventing actuation of the trip lever by the solenoid plunger. Accordingly the trip lever cannot actuate the latch 18 during the starting period and the breaker remains closed and locked in such position until the operator chooses to move the crank 26 back to its initial or intermediate position. When the operating crank is returned to such position the telescopic member 32 is biased by its spring in the corresponding direction so that the tripping lever 23 is free to function upon occurrence of an abnormal overload. Vith this arrangement the operator is free to operate the circuit breaker and prevent tripping thereof upon closure while operating the breaker in the usual manner, the locking out of the tripping device being automatic and concurrent with the closing operation.

It should be understood that my invention is not limited to specific details of construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in the art without departing from the spirit of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. Electric switch apparatus comprising switch operating mechanism, tripping means coacting therewith, means actuated by said operating mechanism positively blocking said tripping means in non-tripping position in accordance with the switch closing operation, and means controlled by said operating mechanism for unblocking said tripping means.

2. Electric switch apparatus comprising a switch operating mechanism, a tripping device coacting therewith, a blocking member controlled in accordance with the switch closing operation for blocking and positively for maintaining said tripping device in a non-tripping position, and spring means unblocking said tripping device after completion of said switch closing operation.

3. Electric switch apparatus comprising switch operating mechanism having a rotatable operating crank, a tripping device coacting therewith including a solenoid and tripping lever, and means including structure positioned in accordance With the switch closing operation of said operating crank so that movement of said tripping lever is blocked, reverse movement of said crank unblocking said tripping lever.

4. Electric switch apparatus comprising a switch operating mechanism having a rotatable operating crank, a tripping device including a solenoid and tripping lever, a

member having a portion arranged to block movement of said tripping lever, and a resilient connection between said member and operating crank, said member moved to said blocking position by said operating crank during the closing movement thereof and subsequently to a non-blocking position by said resilient connection.

5. Electric switch apparatus comprising a manually actuated shaft, switch operating mechanism operatively mounted on said shaft, tripping means including a solenoid actuated tripping lever, a blocking member guided for movement with respect to said tripping lever, said member having a portion arranged to block movement of said tripping lover, a spring biasing said member away from said blocking position, and a member fixed to said shaft and connected to said blocking member arranged so that said tripping lever is blocked when said shaft is moved to closed circuit position, said spring returning said blocking member to a nonblocking position in response to movement of said shaft to an intermediate position.

In witness whereof, I have hereunto set my hand.

J ENS M. JENSEN.

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