US3717733A

US3717733A - Centrifugal switch

Info

Publication number: US3717733A
Application number: US00173587A
Authority: US
Inventors: L Berezansky
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-08-20
Filing date: 1971-08-20
Publication date: 1973-02-20
Anticipated expiration: 1990-02-20

Abstract

An over-center spring device displaces a switch element between open and closed circuit positions with a snap-action motion. A centrifugal mechanism on a rotatable shaft extending through the switch housing, axially shifts a sleeve on the shaft for engagement with the spring device through a bearing member. The sleeve is connected by links to weight elements of the centrifugal mechanism.

Description

United States Patent 1 Berezansky 51 Feb. 20, 1973 [54] CENTRIFUGAL SWITCH Winslow et al. ..200/80 R 3,172,973 3/1965 Gdovichin ct al ..2()0/80 R Primary ExaminerHerman J. Hohauser Attorney-Clarence A. OBrien et a1.

[57] ABSTRACT An over-center spring device displaces a switch element between open and closed circuit positions with a snap-action motion. A centrifugal mechanism on a rotatable shaft extending through the switch housing, axially shifts a sleeve on the shaft for engagement with the spring device through a bearing member. The sleeve is connected by links to weight elements of the centrifugal mechanism.

8 Claims, 6 Drawing Figures WWW SHEET 2 BF 2 ,6 Louis P. BereZan sky INVESTOR.

CENTRI-FUGAL SWITCH This invention relates to an electrical switch mechanism which isactuated in response to rotation o a member above a predetermined speed.

An important object of the present invention is to provide a switch mechanism which is connected by means :of a rotating shaft to any rotating device so as to .c'lose anelectrical circuit in areliable and rapid manner when the speed of the rotating device reaches a predetermined value. Also, the switch mechanism must abruptly open the circuit when the speed of the rotating device .drops below this same value. Although speed responsive .switch mechanisms of such type are known, the present invention provides one that is durable and operative without maintenance or adjustment for prolonged periods of time and which also may be readily repaired by replacement of parts in a facilitated manner.

In accordance with the present invention, a shaft extending through the switch housing has a mounting block secured thereto on which a pair of weight elements are pivotally mounted. When the shaft is stationary, the weight elementsare disposed in a collapsed position abuttingzeach other in enclosing relation to the shaft. In response to rotation of the shaft above a predetermined speed, the weight elements pivot radially outwardly against a torsion spring bias thereby axially shifting an actuator sleeve which is connected to the weight elements by a pair of links. A bearing member rotatably mounted on the actuator sleeve, thereby engages a lever element displacing it toward a switch bracket on which a switch element is pivotally mounted. The switch element is connected to an overcenter spring also mounted on the bracket so as to yieldably hold it in an open circuit position. When the .lever elementis displaced by the actuator sleeve toward theswitch bracket, it laterally deflects the overcenter spring so as to displace the switch element with a snap action motion into engagement with a stationary contact on the switch bracket in order to close an electrical circuit.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof,

wherein like numerals refer to like parts throughout, and'inwhich:

FIG. I is a top plan view of the switch mechanism with the hinged cover of its'housing in an open position.

FIG. 2' is a side section view through the switch housing.

'FIG. 3 is an enlarged side sectional view taken substantially through a plane indicated by section line 3--3 'in FIG. 1.,

tion.

FIG. 6 is a side sectional view through the switch -mechanism showing it in an operative condition corresponding to that of FIG. 5.

Referring now tothe drawings in detail, the switch I mechanism as shown in FIGS. l-through 4, is in an inactive condition and is generally denoted by reference numeral 10. A rotatable shaft 12 extends through the housing generally referred to by reference numeral 14 enclosing the operating parts of the switch mechanism. The housing is secured to a'base or frame 16 and includes parallel spaced

side walls

18 and 20 which are interconnected by

end walls

22 and 24. The end walls

mount bearing assemblies

26 and 28 within which the shaft 12 is journaled. A collar 30 is secured to one end of the shaft beyond the bearing assembly 28 so as to hold the shaft assembled within the housing into which it extends through the other bearing assembly 26. The top of the housing is closed by a hinged cover 32 adapted to be locked to the side wall 20 by a latch device 34 as more clearly seen in FIG. 4. The other side wall 18 has an opening within which a fitting 36 is mounted as shown in FIG. 4. An electrical cable (not shown) is adapted to extend into the housing through the fitting 36 so that a pair of electrical conductors (not shown) may be secured to a pair of

terminal posts

38 and 40 within the housing.

The terminal posts respectively extend from a pivot support element 42 and a contact element 44 carried on the top of a switch bracket 46 made of non-conductive material. The switch bracket 46 straddles the shaft 12 and is secured to the base 16 by right angle leg elements 48. The support element 42 pivotally mounts a movable switch element 50 that is spaced above and extends transversely across the shaft 12. Through the support element 42, the switch element 50 is electrically connected to the terminal post 38. The end ofthe switch element remote from its pivotal axis on the support element 42, mounts a contact 52 that is adapted to engage the fixed contact element 44 on the bracket 46 so as to complete an electrical circuit through the conductors to whichthe

terminal posts

38 and 40 are connected. The switch element 50 is however held in its open circuit position as shown in FIG. 1 by means of an over-center coil spring 54.

One end of the coil spring 54 is connected to the switch element 50 while the other end is anchored to the bracket 46 by means of an extension 56 thereof. In its undeformed condition as shown in FIG. 1, the overcenter coil spring 54 is disposed on one side of the pivot axis of the switch element 50 so as to yieldably hold the switch element in its open-circuit position. The coil spring 54 may, however, be laterally deflected as shown in FIG. 5 past its over-center position to thereby displace the switch element 50 with a snap action motion to its closed circuit position wherein the contact 52 engages the contact element 44. The coil spring is laterally deflected by means of the upper portion of a lever element 58, the lower end of which is pivoted on the bracket 46 to one lateral side of the shaft 12 by means of a pivot bracket 60 as more clearly seen in FIG. 3.

When the lever element 58 is pivotally displaced into engagement with the spring 54, the switch element50 will abruptly engage the contact element 44 in view of the directional change in the bias of the spring resulting from its lateral deflection. Further, the spring 54 will tend to straighten out and assume its undeformed posiv tion as shown in FIG. I when pressure is withdrawn from the lever element 58 so that the switch element 50 may be abruptly displaced to its open circuit position.

Thus, the switch mechanism will have a rapid makeand-break characteristic and will be actuated by a relatively small lateral force applied to the spring 54 through the lever element 58.

An actuating force is applied to the lever element 58 by an annular bearing member 62 rotatably mounted on an actuator sleeve 64 by means of an axial thrust bearing assembly 66 as more clearlyseen in FIG. 3. The bearing member 62, is furthermore limited in the amount of angular displacement it may undergo about the axis of the shaft 12 on which the actuator sleeve 64 is axially shiftable toward and away from the lever element 58. Thus, a relatively rigid fin 68 is secured to the base 16 within the housing and is received with clearance within a slot 70 formed in the lower portion of the bearing member 62 as more clearly seen in FIG. 4. The bearing member 62 may therefore have a limited amount of angular movement so as to avoid undue wear as it engages and disengages the lever element 58. The actuator sleeve 64 is axially displaced toward the lever element 58 for operating the switch mechanism by means of a centrifugal mechanism generally referred to by reference numeral 72.

The centrifugal mechanism 72 includes a mounting block 74 secured by a setscrew 76 to the shaft 12 for rotation therewith in an axially fixed position. The mounting block 74 includes a pair of laterally extending extensions 78 between which a pair of pivot pins 80 are mounted on opposite sides of the shaft 12. A weight element 82 is pivotally mounted on each of the pins 80 so as to abut each other in enclosing relation to the shaft when the shaft is stationary. The weight elements are yieldably held in this abutting position by torsion springs 84 mounted on the pivot pins 80 and anchored at opposite ends to the weight elements and the pivot pins. Accordingly, the bias'of the torsion springs 84 and the mass, of the weight elements 82 will determine the speed at which the weight elements are displaced radially outwardly to positions as shown in FIGS. and 6 under the action of centrifugal force. When pivotally displaced outwardly to the positions shown in FIGS. 5 and 6, the weight elements will axially shift the actuator sleeve 64 to which the weight elements are respectively connected by the links 86 for operating the switch mechanism.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur tp those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1.'A speed responsive switch mechanism comprising a frame, a shaft rotatably mounted by the frame, a contact element, means insulatively supporting said element from said frame, switch means, said switch means including a switch element movably and insulatively mounted for movement relative to said frame and for shifting between open and closed positions relativeto the contact element and over-center spring means supported from the frame and connected to the switch element for biasing the latter toward an open position, actuator means engageable with the switch means for displacing the spring means passed the center position tion, said actuator means including a lever element pivotally mounted in lateral spaced relation to the shaft, an actuator sleeve mounted on the shaft and axially shiftable thereon, bearing means rotatably mounted on the sleeve for engagement with the lever element, and means connected between the shaft and said sleeve for shifting the latter along said sleeve in response to rotation of said shaft above a predetermined speed.

2. A speed responsive switch mechanism comprising a frame, a shaft rotatably mounted by the frame, a nonconductive bracket secured to the frame, a contact element mounted on the bracket, a switch element movably mounted on the bracket, over-center spring means mounted on the bracket and connected to the switch element for biasing the same to an open position, actuator means engageable with the spring means for displacing the switch element to a closed position in contact with the contact element, and centrifugal means connected to the shaft for moving the actuator means into engagement with the spring means, said actuator means including a lever element pivotally mounted in lateral spaced relation to the shaft an actuator sleeve mounted on the shaft and axially shiftable thereon between the lever element and the centrifugal means, bearing means rotatably mounted on the sleeve for engagement with the lever element, and means for limiting angular movement of the bearing means relative to the frame.

3. The combination of claim 2 wherein said centrifugal means comprises a mounting block secured to the shaft, a pair of weight elements adapted to abut each other in a position enclosing the shaft, pivot means movably mounting said weight elements on the mounting block for radially outward movement from said latter position, and link means connecting said weight elements to the actuator sleeve.

4. The combination of claim 3 wherein said spring means comprises a coil spring having opposite ends connected to the switch element and to the bracket laterally spaced from the shaft,.said switch element being pivotally displacable about a pivot axis located on one side of the coil spring in the closed position of the switch element, said coil spring being laterally deflected by the actuator means directionally changing the bias of the spring means.

5. The combination of claim 2 wherein said spring means comprises a coil spring having opposite ends connected to the switch element and to the bracket laterally spaced from the shaft, said switch element being pivotally displaceable about a pivot axis located on one side of the coil spring in the closed position of the switch element, said coil spring being laterally deflected by the actuator means directionally changing the bias of the spring means.

6. The combination of claim 2 wherein said centrifugal means comprises a mounting block secured to the shaft, a pair of weight elements adapted to abut each other in a position enclosing the shaft, pivot means movably mounting said weight elements on the mounting block for radially outward movement from said latter position, and link means connecting said weight elements to the actuator means.

7. In a switch mechanism, a frame, a shaft rotatably mounted by the frame, a non-conductive bracket secured to the frame, a contact element mounted on the bracket, a switch element movably mounted on the bracket, over-center spring means mounted on the bracket and connected to the switch element for biasing the same to an open position, and actuator means engageable with the spring means for displacing the switch element to a closed position in contact with the contact element, said actuator means including a lever element pivotally mounted in lateral spaced relation to the shaft, an actuator sleeve mounted on the shaft and axially shiftable thereon, bearing means rotatably mounted on the sleeve for engagement with the lever element, and means for limiting angular movement of the bearing means relative to the frame.

8. The combination of claim 7 wherein said spring means comprises a coil spring having opposite ends connected to the switch element and to the bracket laterally spaced from the shaft, said switch element being pivotally displaceable about a pivot axis located on one side of the coil spring in the closed position of the switch element, said coil spring being laterally deflected by the actuator means directionally changing the bias of the spring means.

Claims

1. A speed responsive switch mechanism comprising a frame, a shaft rotatably mounted by the frame, a contact element, means insulatively supporting said element from said frame, switch means, said switch means including a switch element movably and insulatively mounted for movement relative to said frame and for shifting between open and closed positions relative to the contact element and over-center spring means supported from the frame and connected to the switch element for biasing the latter toward an open position, actuator means engageable with the switch means for displacing the spring means passed the center position thereof and the switch element toward its closed position, said actuator means including a lever element pivotally mounted in lateral spaced relation to the shaft, an actuator sleeve mounted on the shaft and axially shiftable thereon, bearing means rotatably mounted on the sleeve for engagement with the lever element, and means connected between the shaft and said sleeve for shifting the latter along said sleeve in response to rotation of said shaft above a predetermined speed.

2. A speed responsive switch mechanism comprising a frame, a shaft rotatably mounted by the frame, a non-conductive bracket secured to the frame, a contact element mounted on the bracket, a switch element movably mounted on the bracket, over-center spring means mounted on the bracket and connected to the switch element for biasing the same to an open position, actuator means engageable with the spring means for displacing the switch element to a closed position in contact with the contact element, and centrifugal means connected to the shaft for moving the actuator means into engagement with the spring means, said actuator means including a lever element pivotally mounted in lateral spaced relation to the shaft, an actuaTor sleeve mounted on the shaft and axially shiftable thereon between the lever element and the centrifugal means, bearing means rotatably mounted on the sleeve for engagement with the lever element, and means for limiting angular movement of the bearing means relative to the frame.

4. The combination of claim 3 wherein said spring means comprises a coil spring having opposite ends connected to the switch element and to the bracket laterally spaced from the shaft, said switch element being pivotally displacable about a pivot axis located on one side of the coil spring in the closed position of the switch element, said coil spring being laterally deflected by the actuator means directionally changing the bias of the spring means.