US2757253A - Centrifugal governor - Google Patents

Description

July 31, 1956 A. w. GAUBATZ CENTRIFUGAL GOVERNOR 2 Sheets-Sheet 1 Filed DSC. 5l, 1952 July 31, 1956 A. w. GAUBATZ 2,757,253

CENTRIFUGAL GOVERNOR Filed Deo. 31, 1952 2 Sheets-Sheet 2 f mi() Inventor n Y l Attorneys United States Patent O CENTRIFUGAL GovERNoR Arthur W. Gaubatz, Indianapolis, Ind., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application December 31, 1952, Serial No. 329,033

3 Claims. (Cl. 20G-80) This invention relates to centrifugal governors and, more particularly, to a centrifugal governor suitable for use as a speed sensitive switch in which one or more electrical switches or other control elements are actuated sequentially at predetermined speeds of rotation of an engine or other rotating agency.

The invention has for its general object to effect improvements in the design of centrifugal governors and, more specifically, to provide a centrifugal governor which is extremely compact and of minimum overall dimensions, which is positive and reliable in operation and which is possessed of a high degree of sensitivity and stability.

Among the features of the invention is the provision of novel adjusting means for enabling fine adjustment of the axial position of one or more control elements such as electrical micro-switches, which are mounted within the governor housing, from the exterior of the governor without disassembly thereof whereby the speed setting of the governor may be quickly, conveniently and accurately adjusted,

` Another feature of the invention resides in the provision of stop means for preventing any tendency to rotate of a slidable element which receives the axial thrust of the governor flyweights, whereby erratic and unreliable operation, as is encountered with rotatable slidable elements in other governor structures, may be eliminated. The stop means of the present invention further functions to limit the axial displacement or travel of the said slidable element above predetermined speeds of governor operation.

The above and other objects, features, and advantages attending the invention will appear more fully from the following detailed description and drawings; wherein Fig. i is a longitudinal elevation view, taken in section and with parts broken away, of a governor in accordance with the present invention;

Fig. 2 is a fragmentary transverse sectional View taken in the plane 2 2 of Fig. l;

Fig. 3 is a transverse sectional view taken in the plane 3 3 of Fig. l;

Fig. 4 is a longitudinal View taken in the plane 4 4 of a part of the structure shown in Fig. 3;

Fig. 5 is an end view with parts broken away taken in the direction 5 5 of Fig. l that illustrates a feature of the present invention;

Figs. 6 and 7 are fragmentary detail views taken in the planes 6 6 and 7 7, respectively, of Fig. 5; and

Fig. 8 is a detailed view of a micro-switch suitable for use in the present invention.

Referring to the drawings, the governor mechanism shown in Fig. l may be contained in a generally twopiece cast housing 10 comprising a cylindrical body portion 11, which is open at one end to receive a centrally bored end cover 12 formed with an annular flange 13 extending axially inwardly thereof. The end cover may be detachably secured to the body portion by suitable means as by a pair of bolts 14, one of which is illus- 2,757,253 Patented July 31, 1956 trated in Fig. 4. The opposite end of the body portion 11 is formed by a centrally bored end wall 15 that is provided with a central annular flange 16, substantially as shown.

The governor shaft 17 is mounted for rotation within the governor housing and is supported at one end therein by an anti-friction thrust ball bearing 20, the inner race 2l. of which is pressed on a reduced portion of the governor shaft. The outer race 22 of the shaft bearing iS contained in a collar or bushing 24, which is centrally mounted in the bored end cover 12 and is pinned to the ilange 13 thereof, as shown at 31. The bushing 24 is formed with an outwardly extending radial ange 25, which locates the bushing against the outer face of the cover l2, and with an inwardly depending radial flange 26 adjacent the inner end of the outer race 22 of the shaft bearing. Axial outward movement of the bearing 2i? is prevented by a pair of concentrically disposed snap rings and 23, which are provided near the outer end of the bushing 24 and the shaft i7, respectively, as shown. The governor shaft 1.7 may be counterbored at its opposite ends, as shown at 3G and Sil', the bore 3G at the supported end of the shaft being internally splined or of generally polygonal section to receive the mating end 33 of a speed input shaft 32 that is suitably coupled to an engine, motor or other rotating agency to be driven thereby and thus rotate the governor shaft.

intermediate the ends the governor shaft and integrally formed thereon is radially projecting ilange 34 having formed about the periphery thereof a number of generally duck-bill shaped arms 37 to form a pair of diametrically spaced clevis mounts or bracket arms for a pair of governor iiywcights 35. Each ilyweight is pivotally mounted between a pair of adjacent arms on a clevis pin 40, which extends through the weight and the arms and is retained on the latter, as by small snap rings 42. A roller bearing 44 is provided between the clevis pin ci@ and the flyweight 3S of each bracket arm to reduce rolling friction therebetween. The governor weights may be mounted on two rows of balls with a spacer sleeve 4S of porous bronze saturated with lubricant between the rows of balls.

Spaced from the governor shaft i7 and located on the weight side of the liange 34 opposite the shaft bearing 2i? is an axially shiftable operating element in the form of a coaxial sleeve member 46 which has a camming surface in the form of an annular flange 48 integrally formed intermediate the ends thereof. T he ilange 48 is externally threaded to receive internally threaded insulating collar 5G, which is pinned to the flange 4S, as shown at 51. One end of the sleeve 46 is supported from and is guided in the centrally bored end wall 15 of the governor housing body 1l, and the other end of the sleeve mounts an anti-friction bearing 54, the inner race 55 of which is pressed on the sleeve and bears against the annular flange 4S thereof. The outer race 56 of the sleeve bearing is mounted radially inwardly of and is supported from the ilyweight mounting arms 37 which form a fingered pocket for the sleeve bearing. The pocket formed by the arms 37 is axially bored so that the radially inwardly extending edge of each arm will be of curved or of arcuate section to conform to the circular form of the outer race of the sleeve bearing. The inner edges of the llyweight mounting arms 37 extend parallel to the axis of the sleeve and shaft so as to permit axial movement of the bearing and sleeve relative to the shaft 17. The flyweight bracket arms 37 thus serve to provide a mount for governor flyweight, as well as to center and support the sleeve from the rotating shaft through the sleeve bearing.

Each of the yweights has an inwardly extending tang 5S integrally formed thereon that bears against the side n fr ICC

of the outer race 56 of the sleeve bearing 54 adjacent the shaft flange 34 so as to exert an axial thrust to move the bearing and sleeve as the rotating yweights surrounding the shaft swing outwardly under the influence of centrifugal force.

Movement of the sleeve 46 and, hence, of the ilyweights 38 under the influence of centrifugal force is yieldably opposed by suitable resilient no-nrotating balance means such as compressed coil spring 62, one end of which seats against the side of the annular flange 48 opposite the sleeve bearing and its other end against the edge of the annular flange 16 of the end wall 15, as shown in Fig. l. Any rotational tendency of the sleeve member 46 by reason of the mounting thereof is prevented by means described immediately below, and since the balance spring is mounted against rotation, the erratic and unpredictable action encountered with rotating springs employed in prior art structures will be avoided and smooth, reliable and accurate operation of the governor will be assured.

Since the outer race S6 of the sleeve bearing 54 rotates with the flyweight mounting arms 37 on the flange 34 of the rotating governor shaft 17, frictional forces will be transmitted through the sleeve bearing so as to exert a torque on the slidable sleeve 46. As a result, the sleeve will tend to rotate slowly and may change its axial position so as to impair the accuracy of the governor. The frictional drag of the bearing presents a serious problem, particularly when starting the governor from rest, since the bearing lubricant may be in a congealed condition, whereby a considerable amount of torque may be transmitted through the sleeve bearing.

In solution of this problem, the invention provides a simple stop arrangement which prevents the frictional torque transmitted through the sleeve bearing from rotating the slidable sleeve during operation of the governor. As shown in Figs. 3 and 5, the stop arrangement comprises a screw 64 that extends through the end wall of the housing body parallel to the axis of the shaft and has a threaded portion 65', which receives a threaded nut 66 to secure the screw against the end wall, and a reduced Unthreaded pin portion 67, which is received in a U-shaped slot 68 formed in the rim of the sleeve collar 50. As the walls of the collar slot 63 are always in slidable engagement with the stop screw, rotational tendency of the sleeve will be prevented at all times, and due to the slight amount of sleeve travel, substantially free and frictionless movement thereof will be assured. The Unthreaded portion 67 of the stop screw 64- may have an integrally formed ridge or collar 69 therein that serves to limit the axial displacement of the slidable sleeve above a predetermined speed of operation of the governor.

Mounted within the interior and supported from the end wall 15 of the governor housing body may be one or more control elements which are adapted to be actuated by the sleeve collar 50 when the sleeve 46 has traveled a predetermined axial distance. In the illustrated ernbodiment of the invention, a pair of control elements such as electrical microswitches S-l and S-Z are employed. As best shown in Fig. 3, the switches are mounted, one above the other, on opposite sides of the governor sleeve and shaft. The switches may be arranged to be actuated simultaneously at a particular speed or they may be displaced axially so as to be actuated in sequence at two different speeds, depending upon the control function sought to be accomplished with the control apparatus with which the governor is employed.

The micro-switches are of the conventional snap action, over-center variety, having a limited amount of switch travel, and, as shown in detail in Fig. 8, each switch comprises an insulating mounting base 70 having threaded apertures 71 at the opposite ends thereof, an upturned bracket arm 72, a movable actuator arm '74 that passes through an elongated opening 75 in the upper end of the bracket arm 72, a contact arm 76 that straddles the bracket arm 72 and is in engagement with the actuator arm 74, an integrally formed leaf sp1-ing 78 on the contact arm 76, a stepped bracket arm 00 that forms a stop for a contact 82 on one end of the contact arm 76, and a stationary button 84 presenting a contact head for the contact 82 of the contact arm. Each switch is equipped with three terminal lugs 06, S7, S6 (Figs. 3 and 8) which are electrically connected to the upturned bracket arm 72, the contact button S4 and the stepped bracket arm 80, respectively, by conducting rivets or studs 90, 91, 92, the ends of which are upset to secure the switch elements rigidly to the mounting base. A multi-terminal cable connector 93 is detachably mounted over an opening formed in the cylindrical wall of the housing body, as shown in Fig. 3, whereby to facilitate making of external and internal electrical wiring connections to the switches.

Each switch is mounted from the end wall 15 of the housing by a pair of threaded screws 94, 95, the heads 96, 97, respectively, of which seat in counterbores as 98, 99 formed in the outer face of the end wall 15 (Figs. 3, 4, 6 and 7). The threaded portion of each of the switch mounting screws 94, extends through the housing end wall 15 and is received in a respective one of the threaded openings 71 provided in the switch mounting base 70. Tensioning springs 102, shaped as shown in Fig. 2, are provided on each screw between the inner face of the end wall 15 and the adjacent face of a switch base so as to maintain the head of each screw in contact with the face of the counterbore. The switchsprings are preloaded heavier than the pressure required to operate the switch so that the switch may be held firmly in position without straining the switch base.

Extending transversely to the governor axis and through openings 103 provided in the end wall thereof are a pair of worm screws, as 104, each of which has a pair of spaced threaded portions 105, 106 thereon, as shown in Fig. 5. The threaded portion 106 at the end of each of the worm screws receives a threaded nut as 103 that retains the screw in the housing. As will be noted, the heads 96, 97 of the switch mounting screws 94, 95 are of serrated or generally toothed shape so as to form a pair of worm gear adjusting wheels that mesh with the respective threaded portions 105, 106 of a worm screw 104. The periphery of the governor housing is slotted at the ends of the openings 103 for the worm screws 104 to provide shoulders against which the heads of the worm screws and the worm screw retaining nuts 108 may be seated. In order that the retaining nuts 108 should not tighten up against the housing when the worm screws are turned to adjust the position of the switches, the nuts may be provided with a tight running t with the screw threads, or other suitable and well-known expedients can be employed for accomplishment of this end.

By means of the above described worm screw and adjusting gear arrangement, the axial position of the switches S-il and S-Z can be adjusted quickly and accurately with respect to the governor shaft by turning the adjusting screw from the exterior of the housing Without disassembling the structure. Since the adjusting wheels of both of the mounting screws of a switch are engaged by a worm screw, both ends of the switch base will be displaced axially exactly the same amount, thus assuring balanced movement and accurate alignment of the switches and contributing to the overall accuracy of the governor. The speed setting of the governor may thus be quickly, conveniently and accurately adjusted even while the engine or rotary device is running.

What is claimed is: 1. A centrifugal governor comprising, in combination, a rotating shaft, a plurality of flyweights revolved by said shaft, a sleeve spaced from and moveable axially of said shaft by said yweights, ball bearing means for supporting the sleeve from the shaft against substantial rotational movement, yieldable means mounted against rotation and engaging said sleeve for opposing movement thereof by said yweights, stop means mounted parallel to said shaft and engaging an axially extending surface of said sleeve to prevent rotation thereof, and plural switches mounted alongside said sleeve each having an actuating element disposed in the path of said sleeve for sequential actuation by said sleeve at a different predetermined speed of rotation of said shaft, said stop means being axially adjustable and dening an abutment in alignment with an axial surface of said sleeve for terminating the axial movement thereof after said shaft has exceeded the highest of said predetermined speeds of rotation.

2. A centrifugal governor comprising in combination, a housing, a shaft mounted for rotation in said housing, a plurality of flyweights revolved by said shaft, a sleeve moveable axially of said shaft by said flyweights, means for supporting said sleeve from said shaft, yieldable means engaging said sleeve and opposing axial movement thereof by said flyweights, at least one switch disposed in said housing including an actuating element disposed in the path of movement of said sleeve for actuation thereby at a predetermined speed of rotation of said shaft, a spaced pair of rotatably adjustable support elements extending through said housing into screw thread engagement with said switch, said support elements being provided with transversely aligned worm-wheel portions, and a transversely extending rotatable adjusting member on said housing having a worm-gear portion engaging the worm-wheel portions to impart translational adjustment to said switch.

3. In a speed responsive mechanism of the type including a relatively xed support member, a rotative member, a movable operating member, and speed responsive means interconnecting said rotative and operating members for displacing the operating member with respect to the support member in proportion to the speed of the rotative member, the improvement which comprises a translationally adjustable mounting member for an electrical switch, a spaced pair of rotatably adjustable support elements extending through said fixed support member into screw thread engagement with the mounting member resilient means interposed between the fixed support member and the mounting member for urging the members apart, said support elements being provided with transversely aligned worm-wheel portions, va transversely extending, rotatable adjusting member on said support member having a worm-gear portion engaging the worm-wheel portions to impart translational adjustment to said mounting member, and an electrical switch on said mounting member having an actuating element disposed in the path of said operating member.

References Cited in the le of this patent UNITED STATES PATENTS 2,478,142 Ward Aug. 2, 1949 2,617,904 Anderson Nov. l1, 1952 2,627,188 Gaubatz Feb. 3, 1953 2,639,135 Sloan May 19, 1953 2,677,733 Haley May 4, 1954

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