US1848902A

US1848902A - Switch operating mechanism

Info

Publication number: US1848902A
Authority: US
Priority date: 1930-04-18
Publication date: 1932-03-08
Anticipated expiration: 1949-03-08
Also published as: GB372529A

Description

March. 8, 1932. R. PAXTON ET AL SWITCH OPERATING MECHANISM Filed April 18, 1930 3 0 8 nl. 0L n a r s 0 t PG t m 5 .A P. .L z vn g e s u l: bw h 3 M22 0 T a u 7 4 /5 MB L n 4 m a a H M 2 2 M 5 7 0 5 d W 4 O 2 u 5 x w w 7 6 9 n a 4 74% my 8\ y 355 A 6 8 2/0 g L 3 latented Mar. 8, 1932 UNITED STATES PATENT OFFICE ROBERT IPAX'ION, F PHILADELPHIA, AND LUDVIG SEVEBIN WALLE, OF LANSDOW'NE, I

PENNSYLVANIA, ASSIGNOBS TO GENERAL ELECTRIC COMPANY, A CORPORATION 01' NEW YORK SWITCH OPERATING MECHANISM Application filed April 18,

'Our invention relates to switch operating and controlling mechanism and more particularly to an operating mechanismof the reverse-trip type for circuit breakers wherein the breaker is tripped open in response to reverse, or opening movement of the movable switch member during the circuit closing operation thereof. Y

In the operation of large capacity circuit breakers, a short circuit or other fault in the circuit controlled by a breaker may produce repellent magnetic forces of such magnitude reacting on the movable contact blade that complete closing of the breaker is rendered diflicult. When the closing force is applied by means of centrifugal mechanism, for example, as the well-known fiyball operating mechanism, these repellent magnetic forces may overcome the closing force as soon as the coacting switch contacts make engagement, with the result that theoperating'mechanism and movable contact structure are forced open again, i. e., are caused toreverse in movement.

energized until the breaker is in its fully closed position, the closing operation will be repeated with the same result. This alternate opening and closingof the-mechanism, commonly known as pumping, is undesirable since severe burning of the contacts may occur due'to arcing during the incomplete closing operations.

Another consideration is that of properly checking the rebound of the mechanism when the breaker is opened one. short circuit or fault tending to force the movable switch blade open at high speed. In the event that the rebound of the switch blade towards the closed position is an appreciable part of the entire operating stroke, arcing between the contacts may be established or reestablished, thereby possibly causing failure of the breaker, 4

It is a principal object of our invention to provide an improved switch operating and controlling mechanism for circuit breakers wherein the breaker is tripped open in response to reverse movement of thebreaker Since'the motive means for the operating mechanism generally remains- 1930. Serial No. 445,481.

accompanying drawing, and the features of novelty which characterize our invention will be pointed out with particularitv in the claims annexed to and forming a part of this specification.

Referring to the drawings, Fig. 1 is a part- 1y diagrammatic view of switch operating and controlling mechanism in the open circuit position thereof; Fig. 2 is a similar view I illustrating the mechanism in its circuit closing position,.and Fig. 3 ;is a view showing the mechanism in an intermediate position during a reverse-trip operation.

' Our invention is illustrated in a switch operating system comprising a switch operating member 1 operatively connected in a well known manner to the movable contact struc ture of the circuit breaker, not shown, a centrifugal flyball operating mechanism 2, and

suitable motive means for actuating the same, as the electric motor 3. The centrifugal operating mechanism, when rotated by the motor, is adapted to transmit movement to the switch operating rod 1 through toggle structure and straight-line mechanism presently to be described.

' For this purpose the flyball mechanism 2 is operatively connected through the links 4 a and 5 to the central pivot of the toggle 6-7,

having a pivotal connection 8 with structure hereinafter described for maintaining that portion of the toggle stationary during normal closing operation of the switch. The toggle is likewise pivotally connected at 9 to .one arm of a bell crank 10, pivoted at 11, whose opposite arm is connected at 12 to a link 13 associated with a straight-line mechanism forimparting' reciprocal movement to the the operating rod 1. The link 17 is pivotally connected at 19 to the guiding link 20 pivoted at 21, whereby the operating rod 1 is restrained in straight-line motion in response to movement of the link 17.

The link 13 interconnecting the bell crank 10 and straight-line mechanism above described, is pivotally connected at 22 to the link 17 intermediate the pivots 16 and 19. An energy storing device, as a compression spring 23 guided on a tubular member 23, is disposed between the movable pivot 22 and the fixed pivot 15 whereby counter-clockwise movement of the link 17 causes a collar 24; movable with respect to the tubular member 23' to be forced against the free end of the spring to effect compression thereof.

The switch operating mechanism in the position illustrated in Fig. 1 is in the open circuit position. Closure of the breaker mechanism may be effected by energizing the motor 3, thereby causing the flyball mechanism to assume the position illustrated in Fig. 2 in which straightening of the toggle 6-7 is effected. In straightening the toggle, thrust is transmitted to the pivot 9 which causes clockwise rotation of the bell crank 10, and consequent downward or closing movement of the switch operating rod 1. Suitable means (not shown) for deenergizing the circuit of the motor 3 when the switch closing operation is completed may be associated with the closing mechanism, as for example, an adjustable member connected to the operating toggle link 6.

For the purpose of preventing rebound of the mechanism during this switch closing movement, the toggle link 7 is provided with a pin 25 adapted to be engaged by a pivoted latch 26 when the toggle assumes its straightened circuit closing position. As illustrated in Fig. 2, the latch 26, which is normally biased against a stop member 27 by a spring 28, is adapted to hook under the pin 25 and thereby hold the toggle in its straightened position for preventing rebound thereof.

The controlling mechanism for the toggle 67 comprisesa restraining toggle 2930, the" central pivot of which comprises the pivoted connection 8 with the toggle link 6. The

, link 29 of the restraining toggle is provided with a stationary pivot 31 and is adapted to engage the limit member 32. I The toggle link 30 is pivotally connectedto one arm of a bell crank 33 having a fixed pivot 34 and provided at its opposite end with a pin or the like 35 for coacting with a notched or cam portion at one end of a pivoted locking member 36. The

locking member 36 may be controlled by the usual tripping magnet 37 whose movable core 38 when actuated engages and causes clockwise movement of the locking member 36, thereby permitting the pin 35 to move out of its restraining notch and to ride over the top edge of the locking member as illustrated in Fig. 3 for permitting counter-clockwise movement of the bell crank 33 and the consequent collapse of the toggle 67. It shall be noted that the pivot 8, which is free to move laterally upon release of the bell crank 33, permits the toggle 67 to likewise move laterally, shifting the pin 25 therewith so that the latch 26 is not efle'ctive to prevent subsequent collapse of the toggle and opening movement of the switch by the compression spring 23. In other words, the reacting forces opposing the restraining forces in the mechanism, referring to Fig. 2, act longitudinally of the toggle 6-7 tending to rotate the link 29 counter-clockwise. When release of the bell crank 33 occurs, the toggle 6-7 shifts laterally before collapsing, thereby moving the pin 25 out of engagement with the latch 26. Accordingly, the latch 26 is effective to prevent downward movement of the toggle 6--7 after it has been straightened to prevent rebound thereof, but is ineffective to prevent lateral movement and the conseq'uent trippingoperation.

'When the circuit breaker mechanism 1s tripped in response to overload, or other causes, it is rapidly moved to open circuit position by the compression spring 23, and y the repellent magnetic forces set up by the current traversing the switch. During this 1 operation the bell crank 10 is rotated in a counter-clockwise direction from the position illustrated in Fig. 2 to that illustrated in Fi 1 wherein it engages a limit member 40. ince this opening movement may be with considerable force, a certain amount of rebound of the movable switch structure may be expected tending to rotate the bell crank 10 away from its limit member 40. For the purpose of preventing this rebound, there 1s provided 2. lug 41, pivoted at 16, and fixed with respect to the link 17 so that the link 13 is actually engaged and thrust forward when the operating mechanism moves to the open For the purpose of providing reverse-trip operation wherein the breaker is tripped open in response to reverse movement of the mechanism during" the closing operation, either prior to or after actual engagement .of the contacts, the toggle 6-7 is associated of a lever 44 having a fixed pivot 45 and a pivotal connection 46 with the links 4 and 5 connected to the flyball operating mechanism 2. The lever 44 is likewise adapted to engage a stop member 47 which serves to limit the closing movement of the mechanism. A floating member, as a bar 48 supported at its opposite ends by the pivoted links 49 and normally biased upwardly against a stop member 50 by a spring 51, is rovided with ratchet teeth 52, or the like, a apted to be engaged by the latch 42. The bar 48 has secured thereto a pin 53, adapted when the bar is lowered to cause rotation of the tripping member 36 through a lever 54 in a clockwise direction. For this urpose, the lever 54 is connected to the mem er 36 by a link 55 through a lost motion connection, as the slot 56, which receives a pin 57 secured to the member 36.

- .Accordingly, as best illustrated in Fig. 3,

the tripping magnet 38 may cause clockwise movement of the member 36 independently of the link 54 by reason of the pin and slot connection for tripping open the breaker, and

' the link 54, upon clockwise movement may likewise rotate the member 36 independently of the tripping magnet. r

The operation of the reverse tripping mechanism above described is as follows:

Assuming the mechanism to be in the position illustrated in Fig. 1, energization of the motor 3 through suitable circuit connections to cause closing movement of the switch produces clockwise rotation of the pawl carry-v ing lever 44 and consequent engagement of the latch or pawl 42 with the ratchet teeth 52. The latch spring 43 biases the latch into enagement with these teeth which areformed so as to permit the latchto ride over the same during upward movement thereof without resistance. If now, because of repellent forces opposing closing of the switch, or for other causes, the centrifugal closing force is overcome and the mechanism starts to reverse while the motor is energized and, the flyball structure revolving, the lever 44 is accordingly moved in the reverse or counter-clockwise direction so that the latch 42 immediately engages one of the ratchet teeth to transmit downward movement to the bar 48. It is at once apparent that such downward movement of the bar 48, in causin clockwise movementof the members 54 an 36, as'illustrated in Fig. 3, permits immediate tripping of the mechanism and consequent deenergization eration.

.by Letters Patent of the United States, is:

of the motor 3 by suitable connectibns (not shown), so that pumping, or alternate openin and closin of the mechanism is effective y preclude In other words, the motor 3 is deenergized in response to the first reverse tripping operation re ardless of the position of the flyball operating linkage so that the mechanism remains in the open circuit position until again actuated by the operator. The ratchet bar 48, after it has been released by the latch 42, is returned to its normal position by its spring 51, thereby resetting the' tripping mechanism so that it is in readiness for a subsequent circuit closing op- Effective engagement between the pawl 42 and the ratchet teeth 52 is insured by "the vertical mounting of the ratchet bar 48 on the pivoted links 49 and by the pivotal mounting of the pawl carrying lever 44, thereby causing the ratchet teeth to remain in the arc traversed by the pawl until tripping is accomplished. Since a comparatively small reverse movement of the pawl is sufficient to .cause trippin it will be apparent that the breaker may be opened practically immediately upon reverse movement thereof.

' It shall be understood that our invention is not limited to the specific details of construction or arrangement thereof herein il- 95 lustrated and that changes or modifications may occur to one skilled in the art without de arting from the spirit of our invention.

hat we claim as new and desire to secure '1. Switch operating and controlling me ch' anisnr comprising a switch operating member, electro-motive means for efiectmg the switch closing movement of said member, a

collapsible connection between said member and motive means for transmitting movement to said member, and means responsive to reverse movement of the switch operating mem-- ber during the switch closin operating for efi'ecting collapse of said co apsible connection and consequent switch opening movement, notwithstanding continued and concur- 1 rent operation of said motive means in the circuit closing direction.

2. An operating and controlling mechanism for large capacity circuit breakers comprising a switch operating member, electro- -motiye means for causing switch closing movement of said member,- a collapsible thrust-transmitting connection between said motive means and member for transmitting closing movement to the member, and tripping means associated with said collapsible connection for causing collapse thereof and consequent opening of the breaker in response to reverse movement of the operating member during the 'switchsclosing operation, not- .withstanding continued and concurrent application of the switch closing force.

3.An'operat1ng and controlhng mechaneaaaoa nism for large capacity circuit breakers comprising a switch operating rod, motive means for causing closing movement of said rod, toggle structure interconnecting said operating rod and motive means for transmitting movement to said rod, and a tripping member connected to and movable with said toggle structure for causing collapse thereof and consequent opening of the breaker in response to reverse movement of the operating rod durin the switch closing operation.

4. 11 operating and controlling mechanism for large capacity circuit breakers comprising a switch operating rod, electro-motive means for causing closing movement of the rod, a collapsible thrust-transmitting connection between said motive means and rod for transmitting motion thereto, and pawl and ratchet means associated with said connection for causing collapse thereof and consequent opening movement of the breaker in response to reverse movement of said operating rod in opposition to the switch closing force of said motive means during any part of the switch closing operation.

5. An operating and controlling mechanism for large capacity circuit breakers cont prising a switch operating rod, a collapsible thrust-transmitting structure for efiecting closing movement of said operating rod, tripping means associated with said collapsible structure for causing collapse thereof and consequent opening of the breaker, and a pawl and ratchet connection between said collapsible structure and tripping means whereby reverse movement of the operating rod during the closing operation is efiective to actuate the tripping means to open the breaker.

6. Switch operating and controlling mechanism comprising a switch operating rod, an electro-motive device for causing switch closing movement of said rod, a collapsible connection between said device and operating rod for transmitting closing movement thereto, tripping means for permitting collapse of said connection and consequent opening of the switch, a floating ratchet bar operatively connected to said tripping means, and a pawl connected to said collapsible connection and responsive to reverse movement of the operating rod during the switch closing operation for engaging said ratchet bar and actuating the tripping means for causing opening of the switch.

7 Switch operating and controlling mechanism comprising a switch operating rod. motive means for causing switch closing movement of said rod, a collapsible connec tion between said motive means and rod foi transmitting closing movement thereto am for permittingopening movement thereof tripping means for causing collapse of sait connection and consequent opening movement of the switch, a ratchet bar having a.

8. In a switch operating mechanism comprising a switch operating rod and a linkage structure for transmitting switch closing movement to said rod, means for preventing rebound of the switch rod and linkage structure upon opening of the switch, comprising a member forming part of said linkage struc ture and a stop member, said first-namedmember adapted to engage a toggle comprising part of the linkage structure for actuating the same to an overset position whereby the reaction of the rebound tends to force the linkage structure through said overset toggle into firm engagement with the stop member.

' 9. In a switch operating mechanism comprising a switch operating rod, and a collapsible structure for transmitting closing movement to the rod, means for preventing rebound of the switch rod upon closing movement thereof, comprising a latch member, and an element forming part of said collapsible structure adapted to be engaged and restrained by said latch member substantially upon completion of the switch closing movement, said latch restraining said structure from rebound while permitting normal collapse of said structure in response to a switch tripping operation.

In witness whereof, we have hereunto set our hands this 16th day of April, 1930.

ROBERT PAXTON. LUDVIG SEVERIN WALLE.