US2285186A - Centrifugal switch - Google Patents

Description

June 2, 1942. B. M. cAI N CENTRIFUGAL SWITCH Filed 001;. 4, 1940 lllll fi llnlllll'll Inventor Ber-nafd M. Cain, by 6 His Attorhey.

, part of this specification.

Patented June 2, 1942 I CENTB-IFUGAL SWITCH Bernard M. Cain, Marblehead, Masa, assignor to General Electric Company, a corporation of New York Application October 4, 1940, Serial No. 359,728

(on. zoo-so) 12 Claims.

My invention relates to centrifugal switches struction, reliable in operation, and which can be readily manufactured.

Another object of my invention is to provide a centrifugal mechanism with improved structure for operating a stationary switch structure so that rattling of the push collar on the shaft is substantially prevented during the speed range when the stationary switch structure. contacts the push collar.

Further objects and advantages of my invention will become apparent from 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 In the drawing, Fig. 1 is side elevation of an embodiment of my improved centrifugal switch mechanism attached to an end of a rotatable member of a dynamo-electric machine shown in its stationary position; Fig. 2 is a side elevation of the centrifugal switch mechanism illustrated in Fig. 1, the rotatable member having attained running speed; Fig. 3 is an end view in partial section of the centrifugal switch mechanism taken along the line 3-3 of Fig. 1; and Fig. 4 is a side elevation in partial section of the end of the dynamo-electric machine in Fig. 1 showing the centrifugal switch mechanism with the switch member on the stationary part of the machine.

Referring to the drawing, in Fig. 1 I have illustrated a centrifugal operating mechanism attached to an end of a rotatable member Ill of a dynamo-electric machine, which mechanism may be used to actuate a switch which is attached to the stationary member of the machine and is in the starting winding circuit. This centrifugal operating mechanism includes a collar Ii composed of any suitable material such as zinc die casting, and which is movable axially on a shaft I! of the machine. This collar I i has an annular shoulder I 3 which may abut against an operating lever H of the stationary switch designated generally by the numeral I5 in Fig. 4. The collar contacts the lever it only when the machine is operating within a predetermined speed range, and above this range the weights move outwardly and the collar moves away from the lever M. This stationary switch structure may be of any suitable type and, as will be seen as the description proceeds, the operating lever of the switch structure may be designed so as to contact the shoulder l3 substantially at only one point, such as through the buifer IS. The stationary switch structure also includes a contact I! which is able member mounted on the operating arm i4 and a relatively stationary contact it, the movable operating arm I! being mounted for movement through a resilient supporting arm l9.

In order to operate the push collar I i so that it will move away from the stationary switch operating lever I! so that the contacts may open at a certain predetermined speed of the rotatable member ill, outwardly movable weights are provided, which may be of any suitable shape, such as substantially parallel disposed portions 20 connected together by an arm 20a. The weights may be made of any suitable material, such as of a zinc die casting or of a fabricated steel construction. The weights 20 are operatively connected to the push collar ii" through relatively rigid links H or by a similar structure. A pair of ribs 22 and 23 is provided on substantially diametrically opposite sides of the push collar 1 i in order to support pivot pins 24, so that one end of each of the links 2| may be pivotally connected to the push collar i l. The other ends of the links 2| are pivotally secured to the weights 20 through pivot pins 25 which in turn are supported between pairs of inwardly extending fingers 25 and 21 which extend outwardly from an axially extending portion 28 of the arms 20a of the weights. The weights 20 are movably mounted on the rotatable member 10 through pivot pins 25 which are supported on upstanding portions 30 of a back or supporting plate 3|. The supporting plate 3i is rigidly fixed to the rotat- ID by screws 32. Any similar mounting would be suitable which would provide the features of this support.

In order to provide a force to oppose the centrifugal force of the outwardly movable weights caused by rotation thereof, a biasing arrangement is provided which includes springs 33 which are each supported at one end through an upstanding lug 34 on the back plate 3| and at the other end through an outwardly extending finger 35 on the weights. The springs 33 are designed so that when each is stretched between a lug 34 and a finger 35, the outwardly movable weights 20 will be held in their inward position by a biasingforce of a value such that the weights will move outwardly when the rotatable member reaches a predetermined speed. It will be noted that as the weights begin to fly outwardly the links 2i move'in a direction such that further movement will increase the force exerted on the collar II by the centrifugal force of the weights.

In order to prevent rattling of the push collar ll even though it pushes against an operating lever of the stationary structure at only on point, I arrange the movable weights 20 and the collar ii so that when the weights are in their inward position as illustrated in Figs. 1 and 3, they will rest against the collar II. This may be accomplished in any suitable manner, and in the illustrated embodiment of my invention I have provided stops on the weights in the form of inwardly extending fingers 36 and cooperating stops on the push collar II in the form of ribs 31 which extend between the collar II and its shoulder l3. Each of the ribs 31 is provided with an inclined plane surface 33 which cooperates with the adjacent inwardly extending portion 36 of the weight 20 in order that the springs 33 may exert a force on the collar ll so as to prevent rattling of the collar during the time when the weights are in their inward position. The surface 38 may be inclined any suitable amount with respect to the longitudinal shaft, axis so that there is a component of force due to the springs exerted in a direction in line with the shaft axis and in a direction perpendicular thereto. Thus, the spring force is absorbed through the collar when the weights are in their inward position. In order substantially to equalize the forces on the push collar II from all sides, the rib members 31 are suitably disposed on the collar so that the torques tending to turn the collar in opposite directions about an axis transverse to the shaft axis will be substantially equal. This is obtained by symmetrically disposing the ribs on both sides of a plane passing through the axis of rotation of the shaft I2, and since the weights 20 also are symmetrically disposed on both sides of the shaft, the springs 33 will cause each of" the weights to push the collar through the cooperating stops with components of force towards the shaft, and in line with the shaft. Furthermore, each of the weights will tend to pull the collar towards the rotatable member ID through the levers 2|. In this manner even though the push collar is loosely disposed on the shaft I! so that it may be easily moved thereon in an axial direction, the push collar II will not rattle during the time when the rotatable member ID is coming up to the critical speed at which time the weights will move outwardly. Therefore, the push collar Il may be acted upon by an unsymmetrical force through the operating lever of the stationary switch mechanism, so longas that force is less than the forces caused by the springs.

When a dynamo electric machine provided with this type centrifugal switch is started the switch and centrifugal operating mechanism is in the position as shown in Figs. 1, 3 and 4 from the time the rotatable member of the machine is stationary until it reaches a predetermined speed. In this positionthe collar H abuts against the buffer l6 of the operating lever I 4 and the stationary and movable contacts are held in a closed position in order to complete a circuit-through a motorstarting winding. When the motor reaches a predetermined speed, however, the starting winding is no longer necessary and so it may be open circuited. At this critical speed, therefore, the weights will begin to move outwardly until they reach the position illustrated in Fig.2. This movement of the weights will cause the push collar II to move axially onthe shaft away from the stationary switch structure to an extent such that the switch contacts I! and I8 will move away from each other. The weights will remain in this outward position until the rotor slows down to a speed such that the force of the springs will cause them to return to their inward position.

In view of the foregoing, it will be seen that I have provided a centrifugal switch which can be readily manufactured and which is operated by a mechanism, which will operate with a minimum of noise. Thus, during a predetermined speed range when the rotatable member I0 is coming up to a critical speed, the collar II will be held relatively rigidly'between the stops 33 and the links 2| due to the force of the springs 33. Therefore, the push collar II will be forced in one direction, that is, towards the rotatable member It by the links 2| and will be in turn pushed in a generally opposite direction through the stops 36 and theinclined portion 38 of the ribs 31. In this manner the push collar II will be prevented from rattling even though it is being. pushed on by an unsymmetrical force due to the one point contact between it and the operating lever of the stationary switch structure H.

Although I have shown and described a particular embodiment of my invention, I do not desire to be limited to the particular embodi-' ment described, and I intend in the appended claims to cover all modifications which do not depart from the spirit and scope of my invention.

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

1. A centrifugal switch including an axially movable collar, a supporting plate, outwardly movable weights, means for operatively connecting said weights to said collar, means for movably mounting said weights on said supporting plate, resilient means connected to each of said weights and to saidsupporting plate for resisting outward movement of said weights, stops on said weights, means on said collar for cooperating with said stops so that the biasing force of said resilient means is substantially absorbed through said collar when said weights are in their inward position, and a circuit controlling device arranged to be actuated by said collar.

2. A centrifugal switch including an axially movable collar, a supporting plate, outwardly movable weights, means for operatively connect-' ing said weights to said collar, means for movably mounting said weights on said supporting plate, resilient means connected to each of said weights and to said supporting plate for resisting outward movement of said weights, stops on said weights arranged to strike said collar when said weights are in their inward position, said stops and collar cooperating with said operatively connecting means and said resilient means so as to prevent rattling of said push collar, and a circuit controlling device arranged to be actuated by said collar.

3. A centrifugal switch including an axially movable collar, a supporting plate, outwardly movable weights, means for operatively connectably mounting said weights on said supporting plate, resilient means connected to each of said weights and to said supporting plate for resisting outward movement of said waights, a circuit controlling device having an operating means, said device being arranged to be actuated by said collar through said operating means, said operating means being arranged to abut against said collar so as to produce an unsymmetrical force thereon, and stops on said weights arranged to strike said collar when said weights are in their inward position so that the force of said resilient means substantially prevents rattling of said collar due to the unsymmetrical force thereon.

4. A centrifugal switch including an axially ingsaid weights to said collar, means for movably mounting said weights on said supporting plate, resilient means connected to each of said weights and to said supporting plate for resisting outward movement of said weights, stop means on said collar symmetrically disposed on both sides of a plane passing through the axis of rotation of said collar, stops on said weights arzanged to strike said stop means when said weights are in their inward position, and a circuit controlling device arranged to be actuated by said collar.

5. A centrifugal switch including an axially movable collar, a supporting plate, outwardly movable weights, means for operatively connecting said weights to said collar, means for movably mounting said weights on said supporting plate, resilient means connected to each of said weights and to said supporting plate for resisting outward movement of said weights, means on said weights for striking said collar so that said biasing means exerts a force on said weights in a general direction opposite to that force exerted on said weights through said operatively connecting means, and a circuit controlling device arranged to be actuated by said collar.

6. A centrifugal switch including an axially movable collar, a supporting plate, outwardly movable weights, substantially rigid means pivotally mounted on said weights and said collar for connecting said weights to said collar, means for movably mounting said weights on said supporting plate, resilient means connected to each of said weights and to said supporting plate for resisting outward movement of said weights,

.means on said weights for striking said collar when said weights are in their inward position so as to exert a force in a direction substantially opposite to the force exerted on said collar through said rigid means, and a circuit controlling device arranged to be actuated by said collar.

7. A centrifugal switch including an axially movable collar, a supporting plate, outwardly movable weights, substantially rigid means pivotally mounted on said weights and said collar for connecting said weights to said collar, means for movably mounting said weights on said supporting plate, resilient means operatively connected to said weights and to said supporting plate for resisting outward movement of said weights, ribs on said collar symmetrically disposed on both sides of a plane passing through the axis of rotation of said collar, stops on said weights arranged to strike said ribs when said weights are in their inward position, and a circuit controlling device arranged to be actuated by said collar.

8. A centrifugal switch including an axially movable collar, a supporting plate, outwardly movable weights, substantially rigid means pivotally mounted on said weights and said collar for connecting said weights to said collar, means for movably mounting said weights on said supporting plate, resilient means operatively connected to said weights and to said supporting plate for resisting outward movement of said weights, a circuit controlling device having an Operating means. said device being arranged to be actuated by said collar through said operating means, said operating means being arranged to abut against said collar at a point near the outer periphery of said collar, and means on said weights for striking said collar when said weights are in their inward position so that said resilient means substantially prevents rattling of said collar when said operating means abuts against said collar.

9. A centrifugal switch including an axially movable collar, a. supporting plate, outwardly movable weights, substantially rigid means pivotally mounted on said weights and said collar for connecting said weights to said collar, means for movably mounting said weights on said supporting plate, resilient means operatively connected to said weights and to said supporting plate for resisting outward movement of said weights, a circuit controlling device having an operating means, said device being arranged to be actuated by said collar through said operating means, said operating means being arranged to abut against said collar at a point near the outer periphery of said collar, ribs on said collar symmetrically disposed on both sides of a plane passing through the axis of rotation of said collar, and stops on said weights arranged to strike said ribs when said weights are in their inward position so that said resilient means exerts a force on said weights in a direction substantially opposite to that force exerted on said weights through said rigid means in order to prevent rattling of said collar.

10. A centrifugal mechanism, including a rotatable body, a collar mounted thereon for axial movement, outwardly movable weights, means for operatively connecting said weights to said collar, means for pivotally mounting said weights on said body, resilient means connected to each of said weights and to said body for resisting outward movement of said weights, stops on said weights, and means on said collar for cooperating with said stops so that the biasing force of said springs is substantially absorbed through said collar when said weights are in their inward.

position in order to prevent rattling of said collar on said shaft.

11. A centrifugal mechanism including a rotatable shaft, a collar concentric therewith and mounted for axial movement, outwardly movable weights, substantially rigid means pivotally connected to said weights and to said collar, means for pivotally mounting said weights on said shaft, resilient means operatively connected to said weights and to said shaft for resisting outward movement of said weights, stops on said weights, and inclined plane means on said collar for abut ting against said stops when said weights are in their inward position so that said resilient means tends to force said collar toward said shaft in order to prevent rattling of said collar on said shaft during a speed range when the centrifugal force of said weights is less than the force exerted on said weights by said resilient means.

12. A centrifugal switchincluding an axially movable collar, a supporting plate, outwardly movable weights, means for operatively connecting s'aid weights to said collar, means for movably mounting said weights on said supporting plate, resilient means connected to each of said weights and to said supporting plate for resisting outward movement of said weights, a circuit controlling device having an operating means, said device being arranged to be actuated by said collar through said operating means, said operating means being arranged to abut against said collar so as to produce an unsymmetrical force thereon, and means including said resilient means for substantially preventing rattling of said collar due to said unsymmetrical force when said weights are in their inward position.

BERNARD M. CAIN.

Images