US2638518A - Speed-responsive device - Google Patents

Description

May 12, 19,53 G. T.A RANDOL 2,638,518

SPEED-RESPONSIVE DEVICE Filed Jan. 18, 1951 lll/A IN VEN TOR:

-. Glenn T. Randal,

BY w 34 /0 Qw @@Wf 4..

ATToR EYs.

Patented May 12, 1953 UNITED STATES PATENT OFFICE 15 Claims.

The present invention relates to a speed-responsive device, and more particularly to such a device in which centrifugal force is utilized -to cause movement of a movable member for actuating a control element to one of a plurality of positions in which the operation of a multi-stage control device is effected.

Many various types of speed-responsive devices have been proposed in the prior art, and these devices typically utilize weighted members which are flung outwardly under the effect of centrifugal force for causing axial movement of a switch contact member or the like. However, some measure of centrifugal force is exerted upon the movable members, even at those speeds insufficient to actuate the device, thus resulting in hunting or searching of the axially movable element at intermediate speeds. Because of this undesirable characteristic, the prior art devices are not instantly operable but rather are operable over a relatively wide range of speeds.

The present invention provides an improved centrifugal-type speed-responsive device wherein a snap-action" movement is obtained, thereby omitting the formerly necessary hunting or searching at intermediate rotational speeds. structurally, the device of the present invention is quite simple in manufacture and operation, the structure including a rotatable shaft, axially separable rotatable elements which cooperatively define a radially outwardly decreasing chamber therebetween, the chamber having means interposed between the separable elements for movement radially of the shaft under centrifugal force. Spring means are mounted within' the centrifugal chamber to act upon the movable means therein, the actual axial separation of the rotatable elements being effected by coaction of the centrifugally movable means and the spring means carried by one of the separable elements. The spring means are so designed to give a snapaction separation of the members so that a sharp demarcation between the operative positions of the elements is obtainable.

Itis, therefore, an important object of the present invention to provide an improved centrifugally operated speed-responsive device capable of accurate snap-action when an operative speed is attained.

Another important object of the present invention is the provision of a two-stage centrifugal speed-responsive device or governor utilizing centrifugal force-responsive means for imparting a snap-action to a movable control element to actuate the control element to an operative position, while eliminating hunting of the control element.

A furtherimportant object of the present invention is to provide a centrifugally operated speed-responsive device having a pair of'operative positions and an intermediate non-operative position attainable at extremely low operating speeds.

Another and more specific object of the present invention is the provision of a multi-stage governor having anti-friction elements movable in response to centrifugal force exerted thereon against the resistance of a resilient spring means, so that a snap-action actuation of the control element to a plurality of different positions is obtainable.

An important feature of the present invention is the utilization of resilient spring means interposed in the path of centrifugal force travel of an anti-friction element, the spring means being effective to sensitize the anti-friction elements to insure instant modulation of the element radial positions in accordance with the varying speeds and centrifugal forces exerted upon the elements. This modulation eliminates any tendency of the anti-friction elements to hang at any point in the path of their radial travel or movement under the influence of centrifugal force, and the spring means also is effective to urge the antifriction elements toward their inoperative position upon a lessening of the centrifugal force acting thereon.

Thus, an additional object of the present invention is to incorporate a novel spring resistance means in the path of centrifugally operable antifriction elements in such a manner that centrifugal force acting on the elements will snap the control element to its second-stage controlling position, while yieldably opposing the centrifugal action to return the anti-friction elements to their first-stage controlling position upon a decrease in the rotational speed to which the device is subjected.

`Other and further important objects of this invention will be apparent from the disclosures inthe specification and the accompanying drawings.

In the drawings:

Figure 1 is plan elevational view of a speedresponsive device of the present invention;

Figure 2 is a vertical sectional view, with parts shown in elevation, taken along the planes II-II of Figure 1 illustrating the device at rest;

,-Figure 3 is a sectional view taken along the plane III- III of Figure 2 showing in detail the slid-able double contact control element of the device;

.Figure 4 is a sectional view taken along the plane IV--IV of Figure 2 and illustrating in detail the rotor and cage assembly of the device;

Figure 5 is a sectional view, with parts shown in elevation, taken along the plane V-V of Figure' 1 and illustrating the device in the position of Figure 2 while .illustrating the means for adJusting the cage-return means;

Figure 6 is a fragmentary sectional view similar to Figure 2 and illustrating the device in a fully operated position; 'and Figures 7-9, inclusive, are enlarged fragment-ary sectional views illustrating the different radial positions assumed by the centrifugal force-responsive means and the axially slidable means during operation of the device to each of its operative positions.

Referring to the drawings:

In Figures 1-9, reference numeral Ill refers generally to a speed-responsive device of the present invention including an exterior casing having an upper cylindrical section II provided with an open top closed by a cap I2 secured to the casing portion II by suitable means, as by screws I3. The cap I2 has an upstanding central dome lli which overlies an interior closed space I6 cooperatively defined by the casing portion I I and the cap I2. The casing is provided with a depending central boss I1 having a further depending protuberance I8 exteriorly threaded, as at I9, for reception by a supporting member 20. The lower boss I'I is provided with an interior shoulder 2l upon which is seated a bearing member 22 which serves to support the upper portion of a shaft 23 depending through the boss I'I Iand the projection I3 and pinned or otherwise secured, as at 2li, to a spiral gear 28 meshing with a similar gear or worm 2 carried by an automotive propeller shaft or a like source of power 28.

The shaft 23 carries at its upper portion a radially outwardly enlarged flange 29 integrally formed with or permanently fixed to the shaft 23 and forming a part of a rotor 3U. The rotor 33 takes the form of a radially outwardly projecting flange joined tothe shaft 23 for rotation therewith, or formed integrally therewith, and having diametrically opposed, generally rectangular slots 3l` formed therein and extending inwardly to a central upstanding post portion 32 of the rotor.

It will also be seen that the outer wall portions' of those sections of the rotor which provide the slots 3 I provide upstanding outer marginal flanges 33 defining the outer limits of the slots, and also it will be seen that the bottom wall 34 of each slot is inclined upwardly and outwardly from they upstanding boss portion 32 of the'rotor, soL that the slot depth decreases radially outwardly of the shaft.

The upper shaft boss 32 is axially bored, as at 36, to provide a chamber concentric` with the shaft 23 and extending therein to a depth substantially equivalent to the height of the rotor 3II. The bore 36 communicates with the space I3 dened in the interior of the casing through radial pressure venting passages 31.

The upper end of the rotor boss 32 is surmounted by a bonnet 33 projecting upwardly therebeyond and movable relative to the rotor. The bonnet is centrally bored, as at 39, to accommodate the passage of an adjusting pin 40 having a cylindrical head 4I snugly fitting within the boss bore 33 and an upper threaded endreceiving a nut 42 contacting the corresponding upper end of the bonnet 3B. A snap ring 43 is positioned within the bore 3G which is peripherally .grooved to receive the same, and a thrust washer lll is bottomed against the lock ring. A compression spring t6 is confined between the thrust portion Mi and the pin head 3| to resiliently maintain the bonnet 38 in seated position upon the upper end of the boss 32,'the spring 46 thus resisting axial separation of the bonnet 38 and the rotor 30.

The bonnet 38 is provided in its lower portion with a radially enlarged iiange All upon which is seated an elongated cage ri having a central aperture 49 receiving the upper portion of the bonnet 33therethrough. The cage is provided with elongated' di-ametrically opposed legs which are deformed downwardly from the aperture 49 into conforming contact with the outer surfaces of the boss 33 and thence radially outwardly, as at 53, for reception by the slots 3| of the rotor. The `arms of the cage are provided with terminal depending portions 5I which contact the upwardly projecting Iouter flanges 33 of the rotor. As perhaps best illustrated in Figure 4, the outwardly deflected arms 50 of the cage i8 depend into and 'substantially close the slots 3| of the rotor 39, and the cage 128 is movable axially of the shaft 23 with the bonnet 38 against the-resistance of the compression spring 46.

The cage legs 50 'are provided with transverse slots 52 within which are positioned resilient leaftype springs 53 having upper portions 53 retained upon the arms by suitable means, as by rivets 55, intreinediate portions 53 (Figures 7-9, inclusive) depending through the slots 52 into the area 1ying between the cage and thev rotor, and depending terminal portions 5l extending downwardly A hump orv curved portion 33 is defined in the leaf springs '53K and outwardly into this space.

at the juncture of the depending portions 5B and the outwardly directed legs 5l' for a ypurpose to be hereinafter more fully described.

It will be noted that the cage 48, in combination with the rotor 33, defines an inner chamber of outwardly decreasing diameter. More particularly, this chamber is provided by the upwardly and outwardly sloping bottom surface 34 -of the grooves 3I in combination with the downwardly and outwardly sloping legs 53 of the cage 58. The

chambers so defined are diametrically opp-osed i. e. are positioned on opposingv sides of the shaft 23, and positioned within these chambers are wedge-members til which may desirably be in the form of anti-friction elements, such as ball bearings.

It will be seen that the elements or bearings 3l! are dimensioned to nt snugly within the vertical dimensions of the chambers when the cage` legs 5i are in abutment with the upwardly extending iianges 33 `of the rotor, in other words when the cage and the bonnet are pulled to their downward'positions by the force of the compression spring t6. In this position, the wedge members 53 abut the rotor boss 32, and, upon rotation of the shaft 32, centrifugal forces due to such rotation will be exerted upon the wedge members 6B' t2 to a greater or lesser extent upon the threaded upper end of the pin.

Thus, the present invention provides means for effecting an axial separation of a pair of rotatable elements in accordance with the centrifugal force exerted upon a rotating wedge` member interposed betweenthe separable elements.

This principle of operation may be utilized to actuate any desired kcontrol means and the resil- 1 ie'nt spring 'means 53 acting upon the wedge means 60 makes possible a multi-stage actuating operation, as will be hereinafter more fully described.

The specific control element utilized in conjunction with the illustrated structure is an electrical switch having a pair of fixed contacts 6I carried by contact arms 52 extending inwardly toward the bonnet 38 from contact posts 63 carried by the cap I2. Lead wires 84 are secured to the post 63 by suitable means, as by. nuts 66. A pair of fixed upper contacts B1 take the form of depending posts carried by the cap dome I4 and secured to lead wires 68 by nuts 69. The contacts 6I and B1 are thus vertically separated so as not to be simultaneously energized. rIlhe contacts 6I may suitably form a portion of a first control circuit, while the upper contacts 61 form a portion of a second control circuit, the circuits being adapted for selective energization by operation of the speed-responsive device I8.

The means for carrying out the selective energization of the separate circuits is provided by a contact disk I0 formed of insulating material and having a central opening 'Il receiving the bonnet 38, so that the disk 'I0 is seated upon the centrol upper portion of the cage 48 with the disk opening 'II registering with the bonnet aperture 49. The upper surface of the disk 78 is provided with an annular groove within which is seated an annular retaining ring I2 surmounted by a snap ring I3 retained by the bonnet. Thus, the contact disk 1D is mounted on the cage 48 and the bonnet 38 for axial movement relative to the shaft 23. Rotation of the disk 'l0 is prevented by depending guiding pins 'I4 extending downwardly from the cap dome I4 toward the disk 'I0 for reception Within disk aperture 16. The disk 'III is thus held against rotation while still being axially movable relative to the shaft 23.

The disk 'l0 is provided with an annular peripheral flange 'I1 having radially inwardly extending terminal legs overlying the outer peripheral portions of the upper and lower disk surfaces. As best shown in Figure 3, the non-rotatable disk ID is provided with the peripheral conductive flange 11, the flange having radially inwardly enlarged portions I8 coinciding in positioning with the position of the respective contacts 6 I-61 and adapted for contact with the same. In this manner, it will be seen that the disk when in its lower position (Figure 2) will close the circuit including the conductors B4, while in its upper position of Figure 6, the flange TI of the disk I0 serves to close the circuits including the conductors 68. O nly one circuit can be closed in either position of the disk and it will be seen that at intermediate disk positions, neither of the circuits will be closed, inasmuch as the plate 'I0 may be suspended between the contacts without physically touching either set of the same.

Operation The operation of the device of the present invention will be evident from the foregoing structural description, and may be summarized as follows:

Rotation of the propeller shaft 28 or other source of rotary drive will cause a correspond-v ing rotation of the shaft 23, the rotor 30, the bonnet 38 and the cage 48, while the contact disk will be held against rotation by the pins 'I4 slidably received within pin passages 16. Rotation of the rotor will subject the anti-friction ellementsn to centrifugal forces which tend to throw'the elements 60 radially outwardly from the shaft, in accordance with well known phys` ical principles. On the other hand, radial outward movement of the elements 68 will be resisted by the force of the compression spring 46 acting upon the bonnet 38 and the cage 48. This resistance of the spring 48 may be varied by adjustment of the nut 42, as hereinbefore explained, and the confinement of the balls 6I within the passages of radially outwardly decreasing dimensions defined by the rotor slots 3I and the bonnet 58 will exert the spring pressure directly upon the anti-friction elements.

However, it will be seen that only relatively low centrifugal force components exerted upon the members 8l] will be necessary to initially urge separation of the rotor and the cage so that the anti-friction members 68 are moved radially outwardly to the position of Figure 8, in which position the balls 58 contact the hump 58 formed in the leaf spring members 53. The hump presents an additional resistance to movement of the balls 88, so that materially greater centrifugal force components acting directly upon the balls are necessary before the balls will assume the position of Fig' ure 9. When the position of Figure 8 is assumed, contact between the plate fiange 'VI and the lower fixed contacts 6I is broken, but the cage has not been moved upwardly against the action of the spring 48 sufficiently to bring about contact between the flange 'l1 and the upper contacts 61. Thus, an operative position is assumed at which both of the circuits controlled by the device are open.

Upon the exertion of further centrifugal force upon the member 80, as upon increasing the rotational speed of the shaft 23, the balls B0 will be further urged outwardly to overcome the increased resistance caused by the hump 58 of the springs 53 and, when the balls are in this condition, the position of Figure 9 is assumed at which the cage 48 is urged to its furthermost upper position as illustrated in Figure 6, at which position the fixed contacts 81 are brought into contact with the flange 10, thereby completing the circuit including the conductors 68. This is an additional operative position of the device in which one of the circuits is energized, this one energized circuit being different from that energized at the rest position of the speedresponsive device or governor.

After the position of Figure 9 has been assumed, it will be noted that the leaf spring 53, and particularly that portion 5l' thereof radially outwardly ofthe hump 58, will be effective upon the balls 60 to urge the same inwardly toward the shaft along the inclined slot surface 34.

In this manner, quick return of the balls 60 in accordance with a lessening of rotational speed of the shaft 23 is assured and the resilient force of the springs 53 is balanced against the centrifugal forces urging the balls 6D outwardly. It will be appreciated that the force of the spring 53 lessens as the balls move inwardly under decreased rotational speeds, with a snap action occurring as the balls travel in either radial direction between the positions indicated in Figures 9 and 8.

The function of the leaf springs are three in number; namely, first the provision of snapaction opening and closing movement of the upper contacts 6l with relation to the contact plate 10 (this action being due to the hump l 58 provided intermediate the length of the spring depending into the chambersl and tendaeeame ing to retain the balls in the position of Figure 8); second, the prevention of ball retention at the outer end oi their radial travel to thereby prevent or delay low-stage setting of the controlled element 'lil despite a reduction in rotational speed (this action is obtained by the spring-action oi the springs 53 urging the balls- 68 inwardly toward the shaft of the position of 'Figure 9); and third, to provide means acting upon the cage 48 to resiliently urge both the cage and the plate 'it superimposed thereon up- `wardly into engagement with the contacts 6l when the balls assume the position of Figure 9.

Thus, the present invention provides a snapaction centrifugally controlled speed-responsive device having definite, separate operative positions at which diiierent control circuits or the likel are energized and having an intermediate position at which neither circuit is energized. The multi-stage governor thus provided is advantageous over the prior art for the reasons hereinbeore discussed.

It will be understood that modiiications and variations may be effected without departing from' the scope of the novel concepts of the present invention as defined in the claims ap-v pended hereto.

I claim as my invention:

1. A speed-responsive device comprising a rotatable shaft, axially separable rotatable elements cooperatively denning a radially outwardly decreasing chamber therebetween, an elongated spring-arm carried by one oi said elements and projecting into said chamber, and an anti-friction element in said chamber for radially outward centrifugal movement as said elements are rotated, said anti-friction element contacting said spring* arm to resiliently urge said members to Separated relation by wedging action against said spring and said one of said elements.

2. A speed-responsive device comprising a rtatable shaft, axially separable rotatable elements cooperatively dening a radially outwardly decreasing chamber therebetween, means in said chamber and contacting each of Said elements for radially outward centrifugal movement as said elements are rotated'to separate said' elements by wedging action thereagainst, and re silie'nt means acting on said means to bias said means radially inward, thereby resisting separa- L tion of said elements.

3. In a speed-responsive device including a rotatable shaft, a rotor rotatable with the Shaft, an axiallyy movable cage also rotatable with the shaft and positioned immediately adjacent the rotor, said rotor and said cage having confronting radially outwardly converging faces, a plurality-of freely movable wedge members interposed between said rotor and said cage for radial movement under the innuence ofy centrifugal forcegenerated upon rotation ci the shaft toef-A tween, spring means carried by one of said ele-K.

ments and having a resiliently deflecting portion extending into said chamber, and means in said chamber for radially outward centrifugal movement as said elements are rotated to effect axial separation of said elements by wedging action in opposition to the resistance of said resilient means.

5. Aispeed-responsive control device comprising a rotatable shaft, axially separable rotatable elementsv mounted on said shaft andcooperatively dening a y radially outwardly decreasing chamber therebetween, leaf-spring means havingl acantilever end portion extending into saidy chamber, and means in said chamber for radially outward centrifugal movement as said elementsA are rotated, said last-mentioned means contacting the cantilever end portion of said leaf-spring means 'after an initial free radial movement to effect further separation of said elements by wedging action thereagainst only after overcoming the resistance'of said leaf-spring means.

6. A speed-responsive device comprising a casing, a rotatable shaft journalled in said casing, a'

rotor xed to and rotatable with said shaft, a cage-immediately adjacent to said rotorand' movable axially of said shaft to a pair'of separated' operative positions, a control element movable axially with said cage, means-interposed between said rotor and said cage in wedged contact'therewith, said last-mentioned means being movablev radially of said shaft under centrifugal forces generated upon rotation thereof to cause axial separation of said cage from said rotor, and' spring means positioned in the path of radial' travel of the said last-mentioned means and contacting the same during its radial travel to reried by one of said elements and projecting into' said chamber, and an anti-friction element in'- said chamber for radiallyr outward centrifugal movement as said elements are rotated, said antifriction element contacting said vaxially separableA elements to urge the same to a first-stage posi-' tion and contacting said spring-arm only afterA rst-stage movement has beenl accomplished to further resiliently urge said members to separated relation and second-stage position againstthe re-`r sistance of said spring means.

8. A speed-responsive device comprising arotatable shaft, axially separable rotatable ele-v ments cooperatively dening a radially outwardly decreasing chamber therebetween, an anti-friction member mounted in said 'chamber for initial 1 radial movement in contact with said elements to move the same relative to one another to a rst separated position, and a resilient springarm carried by one of said elements and projecting into said chamber for contact with said member upon additional radial movement-thereofto bias said elements for relative movement to an further separated operative position.

9. A speed-responsive multi-stage switch comprising a casing, a rotatable shaftjournaled in said casing, axially sep-arable rotatable elements cOOperatively defining a radially outwardly decreasing `chamber therebetween, said'elements being relatively'axially movable to a plurality off` operative stages, acontactdisk carried by one of said elements, spacedA pairs of fixed contacts*- on opposing sides of said disk, said disk normally closing one pair of said contacts and being spaced from the other pair of contacts, an elongated spring-arm carried by one of said elements and projecting into said chamber, and an anti-friction element in said chamber for radially outward centrifugal movement as said elements are rotated, said anti-friction element contacting said axially separable elements to urge the same to a iirst-stage position intermediate both pairs of said contacts and contacting said spring-arm only after first-stage movement has been accomplished to further resiliently urge said members to separated relation and second-stage position at which only the said other pair of contacts is closed.

10. A speed-responsive device comprising a casing, a rotatable shaft journalled in said casing, a rotor fixed to and rotatable with said shaft,

a cage normally immediately adjacent to said rotor and movable axially thereof relatively to a pair of separated operative positions, a nonconductive Contact disk carrying a movable contact element and movable axially with said cage,

pairs oi axially separated xed contact elements mounted on said casing in the path of axial movement of said movable contact element, said movable contact element normally being in contact with one of said pairs of xed elements and being spaced from another pair thereof, means interposed between said rotor and said cage in wedged contact therewith, said last-mentioned means being movable radially of said shaft under centrifugal forces generated upon rotation thereof to cause axial separation of said cage from said rotor and axial movement of said contact disk to carry said movable contact element from contact with said one of said pairs of xed elements into contact with the other pair thereof, manuallyadjustable spring means operably opposing said centrifugal forces, and leaf spring means positioned in the path of radial travel of the said lastmentioned means for yieldably resisting movement thereof to axially separate said cage from said rotor when subjected to predetermined centrifugal force.

11. A speed-responsive control device comprising a rotatable shaft, axially separable rotatable elements mounted on said shaft and cooperatively defining a radially outwardly decreasing i chamber therebetween, leaf-spring means extending into said chamber, and means in said chamber for radially outward centrifugal movement as said elements are rotated, said lastmentioned means contacting said leaf-spring means after an initial free radial movement to effect further separation of said elements by Wedging action thereagainst only after overcoming the resistance of said leaf-spring means, said leaf-spring means also biasing said last-mentioned means radially inwardly after separation of said elements has been accomplished to effect a rapid radially inward return of said means.

12. In a centrifugally-operated governor having a pair of rotatable axially separable elements and at least two anti-friction members interposed therebetween for radial movement to separate said elements; the improvements which comprise leaf-springs secured to one of said elements and angularly formed to provide a projection radially disposed therebetween in the path of movement of each of said anti-friction members, said leaf-springs yieldably functioning as a first deflectable stop against which said members are eiective during radial travel thereof, a limit stop carried by the other of said elements to prevent the displacement of said members from interposed position, said limit stop being contacted by said members only after yieldably deflection of the leaf-springs, whereby twostage axial separation of said elements is effected in response to increasing centrifugal force.

13. In combination, a pair of rotatable axially separable governor members, one of said members having a frustro-conical radial surface cooperating with a corresponding surface on the other of said members to denne an interior chamber of radially outwardly decreasing dimensions, a spherical wedge element disposed in said chamber and radially movable in response to centrifugal-force generated upon rotation of said members, adjustable spring means opposing separation of said members, and a resiliently deilectable spring on said other of said members interposed in the path of travel of said wedge element, said last-named spring yieldably inhibiting movement oi said wedge element along said frustro-conical surface until the centrifugalforce of said wedge element exceeds the resistance of said spring.

14. A two-stage governor operative to control the actuation of a control member during both acceleration and deceleration of a governor drive means, comprising a pair of co-rotatable axially separable governor` elements, one of which is operatively connected to said drive means and the other of which is operatively connected to said control member, said elements cooperably defining therebetween a radial chamber of outwardly decreasing dimensions, a Wedge member disposed in and movable radially of said charnber upon subjection to centrifugal-force developed during rotation of said elements, resiliently deformable spring means having a projection extending into said chamber for contacting by said Wedge member during radial travel thereof whereby partially separated position of said elements by wedging action of said member in said chamber is effected with simultaneous biasing of said spring to a stressed condition wherein said spring is retained during movement of said elements to fully separated position in response to further acceleration of the governor drive means.

15. A two-stage governor according to claim 14, including pre-tensioned spring means opposing the centrifugal-force on said wedge member to separate said elements, and manually-adjustable means for varying the tension of said spring means to cause actuation of said control member by said Wedge member at different rotational speeds of said governor drive means.

GLENN T. RANDOL.

References Cited in the nle of this patent UNITED STATES PATENTS Number Name Date 1,698,322 Stobe Jan. 8, 1929 1,910,245 Harrelson May 23, 1933 2,136,252 Rasmussen Nov. 8, 1938 2,187,207 McCabe Jan. 16, 1940

Images