US1935304A - Centrifugal switch - Google Patents

Description

V WEBER Nov. 14, 1933.

CENTRIFUGAL SWITCH Filed May 51, 1932 2 Sheets-Sheet l Nov. 14, 1933. v. WEBER CENTRIFUGAL SWITCH Filed May 51, 1932 2 Sheets-Sheet 2 N 000 0 W 06 3 0 1 O y V Q MW a I// W. L. O A Q m 5 Q 6 MW 3 o w w M o 0 0 06 00 0 INSULATION ivswnrlm Patented Nov. 14, 1933 UNITED STATES PATENT OFFICE 1,935,304 CENTRIFUGAL swrrcn Victor Weber, St. Louis, Mo., assignor to The Emerson Electric Mfg. Co., St. Louis, Mo., a corporation of Missouri Application May 31, 1932. Serial No. 614,353

6 Claims. (01. 200-80) This invention relates to improvements in cenfore, spaced apart and positioned in different trifugal switches; and consists in the novel convertical planes. A lead 11 is connected with the struction hereinafter disclosed. contact 8 and a lead 12 is connected with the An object of the invention is to provide a cencontact 9. The lead 11 is a part of the motortrifugal switch for a motor which is simple in starting circuit and the lead 12 is a part of the construction and which may be assembled with motor-running circuit. Thus, as illustrated in a reasonable range of tolerance in the relative the drawings, there are two circuits controlled position of the parts without impairing successful by the switch, the starting circuit being in series, operation of the device; which will provide for an for example, with a high voltage tap of a transefficient starting contact and which will hold the former and the running circuit being in series contact during the acceleration of the motor; with a low voltage tap of a transformer. which will break rapidly at a critical speed and The movable switch member, as illustrated in within a minimum speed differential; and which the drawings, is in the form of an irregularly will operate with a minimum degree of friction, shaped spring plate having a lower leaf 13, a thus prolonging the life of the switch construccentral rectaiigular portion 14 and an upper leaf ti 15, the upper leaf carrying the two contacts 16 Additional advantages will be apparent from and 17. The central portion 14 of the movable the following detail description, taken in conneccontact member has a rectangular cut-out portion with the accompanying drawings, in which tion 18 through which the armature shaft ex- 20 Fig. 1 is a longitudinal section illustrating the tends, and the walls at the sides of the opening position of the parts in contact relation. are deflected inwardly to form the shoulders 19. Fig. 2 is a view of the same parts illustrating The spring plate is supported by attaching the the switch in the position assumed when the molower margin of the leaf portion 13 of the spring tor is under speed. to the bottom part of the plate 5. The spring 25 Fig. 3 is a cross-section on the line 3-3 of plate is on conductive relationship with a lead 20 Fi 1, for completing the circuits controlled by the Fig. 4 is a cross-section on the line 4-4 of movable switch member. The resilient tendency Fi 1, of the spring plate is to throw inwardly toward Fig. 5 is a cross-section on the line 55 of the face of the armature, the'movement, of 30 Fig 2, course, being limited by the extent of the lateral Fig. 6 is a cross-section on the line 6-6 of space between the faces of the contacts 8 and 9. Fig. 1. In order to prevent the spring from short-circuit- Fig. 7 is a cross-section on the line '7'1 of ing against the housing of the motor, an insulat- Fig, 1, ing washer 21 is mounted over the armature shaft 35 In the embodiment of the invention illustrated forward of the face of the spring member. in the drawings, the switch is shown as asso- The movable switch member is actuated to its ciated with a motor which includes an armature forward position against its resilient tendency to 1 operating in a field structure 2 and an armature move backwardly by a centrifugally controlled shaft 3, which shaft extends at one end through construction which includes a sleeve 22 slidably a cover plate 4 of the motor housing. mounted over the armature shaft. The sleeve 22 The switch construction, which is designed, is provided at its outer end with a flange 23. in the embodiment shown, to alternately open The diameter of the flange 23 is in excess of the and close separate circuits, is supported by the cross-dimension of the opening 18 in the mov- 4 irmer face of the cover plate 4. A plate 5 is able switch member so that, when the sleeve is in insulating strip 6 interposed between the plate pressure against the shoulders 19 of the'movable 5 and the face of the cover plate 4. The plate 5 switch member and force the switchmember carries at its upper margin an insulating plate against its normal spring tendency outwardly to '7 which forms a support for the contact members cause the contacts 8 and 16 to maintain contact 50 and for the circuit leads extending therefrom. adjustment. 105 There are two contacts 8 and 9, the contact 8 In order to insulate the sleeve from the plate being supported by the face of the insulating constituting the movable switch membenan inplate '7 and the contact .9 being supported by a sulating washer 24 is interposed between the forbracket 10 that extends inwardly toward the face ward face of the flange 23 and the spring plate.

55 of the armature. The contacts 8 and 9 are, there- The sleeve 22 carries at its inner end an annular 10 attached to the inner face of the cover with an its outermost adjustment, the flange will exert flange 25, and the inner face of the sleeve is recessed to constitute a seat for a coil spring 26 interposed between the inner end of the sleeve 22 and the face of the armature. The tendency of the spring26 is to move the sleeve 22 outwardly with suflicient force to overcome the tendency of the movable switch member to move inwardly, with sufficient excess pressure to hold the con tacts 8 and 16 in contact engagement to effect a satisfactory conductive contact.

A collar 27 is slidably mounted over the sleeve 22 and between the inner faces of the flanges 23 and 25. The longitudinal dimension of the collar 2'7 is somewhat less than the space between the opposed faces of the flanges 23 and 25, so that the collar may move a limited distance without contacting the faces of said flanges 23 and 25. The collar 27 is provided at its forward end with a flange 28, which flange has oppositely disposed grooves 29 in its peripheral face. A coil spring 7 30 is mounted over the collar 27 and bears against the inner face of the flange 28 at one end and against the face of the armature at the opposite end. The tendency of the spring 30 is to press the collar outwardly so that the flanges 23 and 28 are normally in contact when the motor is at rest. The spring 30 is of sufficient strength to resist the initial force of the centrifugal weights by whichit is actuated.

The centrifugal lever members are supported between plates 31 having spaced arms 32, said plates 31 being supported by the face of the armature and opposed to each other on opposite sides of the armature shaft. Each centrifugal member has a pivot pin 33, which pivot pins extend through the lever members comprising long arms 34 and short arms 35. The arms 34 are laterally connected by a plate 36 to which is attached a weight 37.

Extending transversely between the short arms of each of the weight levers is a pin 38. The pins 38 traverse the peripheral face of the flange 28 of the collar 27 and seat. respectively, in the grooves 29. When the motor is at rest, the long arms of the centrifugal weight members lie parallel with the axis of the armature shaft, and the short arms extend normal to the axis of the shaft. When the armature shaft is rotated, the weight arms of the centrifugal levers move outwardly, which action initially moves the collar 27 against the tendency of the spring 30 longitudinally of the sleeve 22. The initial outward movement of the weights does not cause a movement of the sleeve 22, but the sleeve 22 remains in its forward position, preserving the movable contact member in its restrained contact position. After the collar 2'7 has traversed the space betwen the inner face of the flange 25 and the inner face of the collar 27, the collar abuts against the flange 25, and further outward movement of the weights moves the sleeve 22 inwardly a suflicient distance, with a slight excess movement, to release the movable switch member, whereupon the spring tendency of said member snaps it to its innermost adjustment, thereby effecting contact between the contacts 9 and 19, which position is held by an excess spring pressure of the movable contact member.

When the speed of the armature shaft reduces below a speed holding the weight members in their outermost adjustment, the collar 27 moves outwardly and the sleeve 22 is thus released for outward movement and is pressed outwardly by the spring 26.

The characteristic of the governing mechanism is such that for a critical speed the weights either fly out or return without stopping in any intermediate position. For practical purposes, this actionis true even for a slight increase or decrease in speed during the functioning of the device to open or close the contacts. A rapid break or make of the contacts is thus assured.

It is thus clear that the construction of the switch and the means by which it is operated are such as to provide an efficient contact in either position of the movable switch member, and that the centrifugal actuator for the switch member will operate to produce a rapid breaking and making of the contacts, thus minimizing the tendency to are when the contacts are broken.

It will also be clear that the contacts are so actuated as that sufficient pressure to preserve an eflicient contact will be maintained until the break of the contacts occurs, thereby avoiding increase in resistance in the circuits before breaking contact is initiated.

It should be understood that the advantages of the invention are preserved whether the switch is designed as a double contact'switch or a single contact switch, as the fundamental advantages of a quick break and constant contact pressure would be present if the switch was used as a single contact cut-out switch.

I am also aware that the invention may be modified in numerous details without departing from the spirit of the invention. I, therefore, do not limit myself to the exact construction shown and described, but what I claim and desire to secure by Letters Patent is:

1. In a centrifugal switch having a revolving shaft, a stationary contact, and a movable contact carried by a spring plate, an actuator for said spring plate comprising a sleeve slidably mounted on the shaft, a spring moving said sleeve toward said plate, a collar fitted for sliding movement in respect of said sleeve, abutments on the sleeve limiting the sliding movement of said collar, and centrifugal weight levers operatively connected with said sleeve for controlling the movement thereof and thereby of said collar to restrain and release said spring plate.

2. In a centrifugal switch having a revolving shaft, a stationary support, a pair of spaced con-*- tacts carried by said support, and a movable contact member having a pair of contacts cooperating with the first named contacts, said member being resiliently movable to one contact position; an actuator for said movable contact member comprising a sleeve slidably mounted on the armature shaft, a spring tending to move said 130 sleeve into contact with said movable contact member, a collar loosely fitted on said sleeve, a spring for said collar, means for cooperatively connecting said collar with said sleeve, and centrifugal weight levers operatively connected with said collar tending to move the sleeve out of contact with said movable switch member when the armature shaft has attained a predetermined speed.

3. In a centrifugal switch having a revolving 140 shaft and a stationary contact, the combination including a flexible contact blade actuated in one direction by its inherent resiliency, a spring operated member on the shaft moving said blade in opposition to its normal spring tendency, centrifugal weights supported for revoluble movement with the armature shaft, and a connection between said centrifugal weights and said spring operated member whereby said member is moved in opposition to its spring tendency with a de- 1 layed action in respectrof the movement of said centrifugal weights.

4. In a centrifugal switch having a revolving shaft and a stationary contact, the combination including a flexible contact blade actuated in one direction by its inherent resiliency, a spring operated member on the shaft moving said blade in opposition to its normal spring tendency, an insulating connection between said spring operated member and said blade, centrifugal weights supported for revoluble movement with the shaft, and a connection between said centrifugal weights and said spring operated member whereby said member is moved in opposition to its spring tendency with a delayed action in respect of the movement of said centrifugal weights.

5. In a centrifugal switch having a revolving shaft, a stationary contact, a movable contact and a movable contact support movable in one direction by its inherent resiliency; an actuator for said movable support comprising a member slidably mounted on the shaft, 2, second member having .telescopic relationship with said first named member, a pair of centrifugally operated weights disposed on opposite sides of the shaft and revoluble therewith, and lever connections between said weights and said second named member for moving said member longitudinally of said first named member and then moving said members longitudinally as a unit.

6. In a centrifugal switch having a revolving shaft, a stationary contact and a resilient contactmember, an actuator for moving said resilient contact member comprising a member slidably mounted on the armature shaft of the motor, a spring connected with said member and resisting the normal spring tendency of said resilient switch member, pivoted weight levers revoluble with the shaft, and a resiliently actuated connection between said weight levers and said slidable member for imparting to said member a movement in the direction of the spring tendency of said resilient switch member after said pivoted weight levers have completed a part of their outward travel.

VICTOR WEBER.

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