US2025324A - Switch mechanism - Google Patents

Description

P. W. BAKER SWITCH MECHANISM Filed July 9, 1954 r 7 mm Mm mm W m5 PWAN Patented Dec. 24, 1935 PATENT OFFICE,

SWITCH MECHANISM Paul W. Baker, St. Louis, Mo.,

assignor to Wagner Electric Corporation, St. Louis, Mo., a corporation of Delaware Application July 9, 1934, Serial No. 734,229 9 claims. (01. 200--) My invention relates to centriiugally-operated switch mechanisms for dynamo electric machines and constitutes an improvement in the switch mechanism disclosed in co-pending application Serial No. 642,136 filed November 11, 1932, by Otto Wulfert and myself.

One of the objects of my invention is to produce a centrifugally-operated switch in which the movable contact member of the switch is operated by a single pivotally mounted weight.

Another object of my invention is to produce a centriiugally=operated switch which comprises a minimum number or" parts and is both reliable in operation and economical to manufacture.

Other objects of my invention will become apparent from the following description taken in connection with the accompanying drawing, showing a preferred embodiment thereof, in. whichl igu 'e l is a cross-sectional view of a portion of a dynamo electric machine showing my improved centrifugal mechanism in switch closed position; Figure 2 is a view similar to Figure l but showing the mechanism in switch open position; Figure 3 is a cross-sectional view of the centrifugal mechanism taken on the line 3-8 of Figure 1; Figure d is an end view of the pivoted member; and Figure 5 is an end view oi the support for the pivoted member.

1' have shown my invention applied to the switch for opening the circuit of a split phase winding of a single phase motor but it is understood that it may be employed to operate other types of switches.

Referring to the drawing in detail, the electrical motor shown is provided with a stator i and a rotor The stator has a main field winding a split phase starting winding, the latter beconnected to rigid stationary contacts 3 se cured to the bosses l on the end plate of the motor. A collar or hub is slidably and rotatably mounted on the rotor shaft 6 and carries at its outer end an annular disc '3 of insulating material, said disc being rotatable with respect to the hub. 171s periphery of the disc carries an annular conducting ring and, under the conditions hereinafter described, serves to electrically connect the contacts to close the circuit of the sp t phase winding.

The support 9 of the centrifugally-operated mechanism is secured to the rotor 2 of the motor by suitable means such as screws, and has a pair of outwardly extending arms is positioned along the sides of the rotor shaft. The pivotally mounted weight member it has integral arms 62 pivoted by pins 53 to the arms of the support 9,

said member lying upon one side of the rotor .shaft and being formed as shown in Figure 4 of the drawing, so as to fit closely to the slidable collar or hub 5. The pivoted member it is also provided with a suitable ear M to which is attached the ends A of the two coil springs t5, the opposite ends B or" said springs being connected to an outwardly extending arm it on the support 9. These coil springs extend transversely to and lie onopposite sides or" the axis of the shaft. The central part of each spring lies in a groove ll formed on the inward end of the collar or hub 5. Suitable weights iii are also secured to the pivoted member it as shown, in order to give such member the desired weight.

The preferred position of the fixed ends B of the springs in relation to the plane of the groove ll of the hub is shown in Figures 1 and 2. The hub 5, groove ll, and the arm it are so proportioned and positioned that the ends B lie to the right of the plane of the groove i? when the weight is in retracted position and the switch closed (see Figure 1) and to the left of the plane oi the groove tl when the weight is in its outward position and the switch open (see Figure 2).

It is, or" course, understood that other relationships may be used if found desirable.

Referring to the operation of my improved mechanism, the normal position of the parts when the rotor is stationary, is shown in l and under these conditions the circuit of the split phase starting winding is closed. When the rotor is started and the speed increased, the weights will overcome the opposing force of the spring is and cause the member i i to rotate about its pivot pins This movement causes the ends A o; the springs l5, which are connected to the memher it, to be moved through a substantial are in a direction toward'the rotor and, as a result there= oi, the entire springs will be rotated about their ends B secured to the arm l8 oi the supp rt Since the intermediate part of the springs it lies in the groove ll of the hub 5, the angular movernent of the springs results in a longitudinal movement of the hub, thus carrying the hub in a direction toward the rotor and moving the annu= lar conducting ring 8 out of engagement with the rigid contacts 5- and opening the split phase circult. The position of the parts, when the pivoted member it is swung outwardly under the action or" centrifugal force, is shown in Figure 2. The pivoted member l l, weights i8, and springs iii are so proportioned that the opening of the circuit will occur when the desired percentage of full load speed has been reached. When the contacts member H lies closely adjacent the shaft and the ends A" of the springs lie to the left of the plane of the groove I! in the hub 5. This bend-.

ing of the springs results in a yieldable force holding the contacts in pressure engagement. By having the annular ring 8 yieldably held against the contacts 3, there is no necessity for making the contacts 3 yieldable, as has been done in prior constructions, thereby reducing the cost of manufacture.

Since the ends A of the springs, which are attached to the pivoted member H, lie to the left of the groove IT in the hub when the circuit is closed, the pivoted member II is permitted to rotate through a considerable are before it begins to move the hub 5 and open the circuit. The rotor, therefore, is permitted to assume a substantial speed before the circuit is opened and the opening of the circuit will be quick, thus avoiding sparking at the contacts.

My improved centrifugal mechanism for operating a switch is not only cheaper than constructions wherein two pivoted weights are employed, but is more reliable in operation since the opening of the switch is controlled solely by the single pivoted member. In cases where two pivoted members control the switch, it has been found that the pivoted members are not thrown out simultaneously and the mechanism has a twostage operation, that is, one of the weights may be thrown out by centrifugal force prior to the other weight which. may or may not cause the switch to be opened or partly opened prior to the other weight being thrown out and positively opening the contacts. The use of a single weight also permits greater manufacturing tolerances which would not be possible where two pivoted members are used as such requires that both operated members be of the same weight and the springs of the same tension to secure fairly smooth operation.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a switching mechanism, a stationary contact member, a movable contact member and centrifugal means for moving said movable contact member, said means comprising a rotor, a weight pivoted to the rotor, resilient means for opposing the centrifugal force of the pivoted weight, said resilient means having one end secured to the weight and the other end fixed with respect to the rotor, and means for connecting the movable contact member with the resilient means whereby the movement of the resilient means about its fixed end by the pivoted weight will directly move the movable contact member.

2. In a switching mechanism, a stationary contact member, a movable contact member and centrifugal means for moving said movable contact member, said means comprising a rotor, a pivoted weight, a coiled spring for opposing the centrifugal force of the pivoted weight and having one end connected to said pivoted weight and the other end fixed with respect to the rotor whereby when the pivoted member is moved under the action of centrifugal force the spring will be rotated about its fixed end, and connecting means between the movable contact member and an intermediate part of the spring.

3. In a switching mechanism, a stationary contact member, a movable contact member cooperating therewith, a rotor, a weight pivotally carried by said rotor and positioned at one side of the axis thereof, a tension member having one end connected to the weight and the other end fixed with respect to the rotor and located on the side of the rotor axis opposite the weight, said tension member opposingthe centrifugal action of the weight and being rotated about its fixed end by movement of the weight, and means connecting the movable contact member with an intermediate part of the tension member.

4. In a switching mechanism, a stationary contact member, a movable contact member cooperating therewith, a rotor, a weight pivotally carried by said rotor and positioned at one side of the axis thereof, a tension member having one end connected to the weight and its other end fixed with respect to the rotor on the side of the rotor axis opposite the weight, said tension member being rotated about its fixed end by movement of the weight, the fixed end of said tension member lying in a plane at right angles to the rotor axis which is intermediate similar planes passing through the other end of said tension member when it is at its limits of movement, and means connecting the movable contact member with an intermediate part of the tension member.

5. In a switching mechanism, a stationary contact member, a movable contact member and centrifugal means for moving said movable contact member, said means comprising a rotor, a weight pivoted to the rotor, resilient means for opposing the centrifugal force of the pivoted weight, said resilient means having one end secured to the weight and the other end fixed with respect to the rotor, and means for connecting the movable contact member with the resilient means whereby rotation of the resilient means about its fixed end by the pivoted weight will move the movable contact member,'said connecting means being so proportioned and positioned that the tension member will maintain the contact members in pressure engagement when the weight'is in retracted position.

6. In a dynamo electric machine, the combination of a rotor, a circuit closing device operable by movement of one element in the direction of the axis of the rotor, a weight pivotally carried by the rotor and positioned at one side of the axis thereof, a tension member positioned transversely of the axis of the rotor and having one of its ends connected to said weight and its other end fixed to the rotor for biasing the weight against centrifugal movement, and a connection between the central part of said tension member and the movable element of the circuit closing device whereby the translatory movement of the tension member whenrotated about its fixed end by the pivotal movement of the weight is transmitted to the circuit closing device.

'7. In a dynamo electric machine, the combination of a rotor, a circuit closing device operable by movement of one element in the direction of the axis of the rotor, a weight pivotally carried by the rotor and positioned at one side of the axis thereof, a coiled spring positioned transversely of the axis of the rotor and having one of its ends connected to said weight and its other end fixed to the rotor for biasing the weight against centrifugal movement, and a connection between the central part of said coiled spring and the movable element of the circuit closing device whereby the translatory movement of the coiled spring when rotated about its fixed end by the pivotal movement of the weight is transmitted to the circuit closing device, said connection being so proportioned and positioned as to hold the central part of the coiled spring out of alignment with its ends when the weight is in retracted position and the circuit closing device is closed to thereby yieldingly maintain the elements of the circuit closing device in engagement.

8. In a dynamo electric machine, the combination of a rotor, a circuit closing device operable by movement of one element in the direction of the axis of the rotor, a weight pivotally carried by the rotor and positioned at one side of the axis thereof, a coiled spring positioned transversely of the axis of the rotor and having one. of its ends connected to said weight and its other end fixed to the rotor for biasing the weight against centrifugal movement, said coiled spring being rotated about its fixed end by movement of the weight, the fixed end of said coiled spring lying in a plane at right angles to the rotor axis which is intermediate similar planes passing through the other end of the coiled spring when it is at its limits of movement, and a connection between the central part of said coiled spring and the movable element of the circuit closing device whereby the translatory movement of the coiled spring when rotated about its fixed end by the pivotal movement of the weight is transmitted to the circuit closing device, said connection being so proportioned and positioned as to hold the central part of the coiled spring out of alignment with its ends when the weight is in retracted position and the circuit closing device is closed to thereby yieldingly maintain the elements of the circuit closing device in engagement.

9. In a switching mechanism, a stationary contact member, a movable contact member cooperating therewith, a rotor, a weight positioned on one side of the axis of the rotor, one end of said weight being pivoted to the rotor and the other end extending toward the movable contact member, a pair of coiled springs positioned on opposite sides of the axis of the rotor, one end of each spring being secured to the weight at a point spaced from its pivot and the other end of each spring being fixed to the rotor on the side of its axis opposite the weight, said springs biasing the weight toward the axis of the rotor, and a member connecting the central part of each spring to the movable contact member, said member being provided with a groove receiving the springs.

PAUL W. BAKER.

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