Jan. '7, 1947. C. E. MILLER 2,413,882 . ACTUATOR Filed Oct. 50. 1944 INVENTOR. CHARLES E. MULLER ‘2,413,882 Patented Jan. 7, 1947 UNITED STATES PATENT OFFICE 2,413,882 ACTUATOR Charles E. Miller, Pasadena, Calif., assignor to Bendix Aviation Corporation, South Bend, Ind, a corporation of Delaware Application October 30, 1944, Serial No. 561,141 2 Claims. (Cl. 264-15) 2 1 in the switch mechanism. It is preferable in such devices that the actuator mechanism be completely out of contact with the control switch when the actuator is rotating, to eliminate any friction between the parts. In the drawing: This invention relates to centrifugal actua tors such as may be employed on motor shafts to open or close switches in response to rotation of the shaft above a certain speed. An object of the invention is to provide a par ticularly simple, inexpensive, and reliable actu ator of the type referred to. Fig. 1 is a view showing an actuator in ac cordance with the invention mounted on the end of a motor shaft for actuating the plunger of a Another object is to provide an actuator the parts of which can be very easily and quickly assembled and disassembled. > 10 switch; Fig. 2 is a view of the actuator similar to the Still another object is to provide a centrifu View of Fig. 1, but showing the position of the gal actuator which is substantially immune to in actuator when rotating. jury or damage by rotation at excessive speeds. Fig. 3 is a cross section taken substantially in Other more speci?c objects and features of the invention will appear from the detailed de 15 the plane III—III of Fig. 1; and Fig. 4 is a detail section taken in the section scription to follow of a particular embodiment of IV-IV of Fig. .3. the invention. Referring first to Fig. 1, there is shown a mo Brie?y, the invention comprises, in its pre tor In, of any desired construction, having a ferred form, an open-ended cup-shaped body or frame mounted on the end of the shaft to be 20 shaft H on the outer end of which is mounted an actuator 12 in accordance with the present rotated, and containing an axial shiftable pin invention, for actuating the plunger l3 of a‘ which is adapted to engage the switch plunger switch 14. or other member to be actuated. When the cup The actuator l2 comprises a tubular body, or is not rotating, the pin is maintained in an outer, or projected position, by a spring. Adjacent its . frame, I5 having a central bore iii therein. The rear end of this bore [6 receives the outer end open end, the cup-shaped frame has diametrically of the motor shaft II, and the body l5 may be opposite slots that extend radially and longitudi secured to the shaft for rotation therewith by a nally and guide a pair of bellcrank levers, the pin H. levers being fulcrumed on, a spring wire ring The bore l6 extends forwardly for a substan which is expanded into an annular groove in the tial distance beyond the end of the motor shaft inner surface of the cup-shaped frame. Each II and serves as a guide for a plunger or pin IB bellcrank lever has a long arm extending sub having a head I9 on its outer or front end. A stantially parallel to the axis of rotation and a helical compression spring 20 surrounds the pin short arm extending radially inwardly into con l8 and is compressed between the body member tact with the front end of the axially shiftable and the head I9 of the pin, to constantly urge pin, to oppose the force of the spring. When the the latter axially to the right out of the bore device is at rest, there are no centrifugal forces l6. Outward movement of the pin [8 by the involved, and the spring maintains the pin in spring 20 is limited by a plurality of bellcrank an outer position in which the long arms of the lever elements 22 which are guided for move levers are approximately parallel to the shaft ment in radial slots l5a provided therefor in the and are largely contained within the slots in the frame l5. Each lever element 22 has a long frame. However, when the shaft bearing the arm 23 extending substantially parallel to the actuator is rapidly rotated, the centrifugal force axis of the body 15, and a short arm 24, which is developed in the long arms of the levers swings substantially normal to the long arm 23 and ex them outwardly about their fulcrums, and the short arms of the levers force the axially shift- " able pin inwardly, overcoming the force of the spring. The device is most commonly used to tends inwardly into engagement with the front face of the head l9 of pin 18. All of the lever elements 22 are fulcrumed on a spring wire ring 25 which is positioned in an actuate a controlled element of a switch, which controlled element is in contact with the end of 50 annular groove 26 formed within the skirt por the axially movable pin and, is depressed by the pin when the actuator is stationary. When the actuator rotates at su?icient speed, the pin there in is retracted by the levers, permitting the plunger of the switch to be ejected by a spring 55 tion of the body l5, each lever element having an aperture 21 for receiving the wire 25. As best shown in Figs. 3 and 4, the wire ring 25 is not continuous but is split and originally shaped to a larger diameter than the groove 26 in which it 2,413,882 3 4 is mounted, so that it can ‘be readily assembled and expands into the groove. The resilience of amples of changes that can be made, more than two levers 22 may be employed where greater force is required. It is desirable, however, in order to produce'a balanced structure, that the lever arms be symmetrically positioned about the axis of rotation. I claim: 1. A centrifugal actuator of the type described the wire ring always maintains it in position within the groove because all forces applied to the ring by the lever elements act either out wardly or longitudinally, never inwardly. One end of the ring is preferably turned in as indi cated at 28 to prevent the ring from shifting in the groove and releasing the lever elements, al though in use there‘ is little or no tendency for comprising: a tubular frame member supported for rotation about its axis and adapted to be ro the ring to shift. tated; a controlled element axially aligned with The device can be very readily assembled and 7 said axis and supported for axial movement with disassembled by virtue of the fulcrum structure respect to said frame member; spring means urg involving the ring 25 in the groove 26. Thus, the ing said controlled member axially in one direc procedure for assembling the parts of the actu 1.5 tion with respect to said frame member; a plu ator together is to ?rst place the helical com rality of bellcrank lever elements fulcrumed to pression spring 26 about the pin “3 and insert said frame member for movement in radial the latter in the bore 5 8 far enough to fully com planes, each lever element having a ?rst arm press the spring. Thereafter, the lever elements normally extending approximately parallel to 22 are threaded on to the fulcrum ring 25, and 20 said axis and a second arm approximately normal the levers and ring are assembled on the body to the ?rst arm and extending inwardly into en 22 by sliding the long arms 23 of the lever ele gagement with said controlled element for mov ments longitudinally into the radial slots in the ing the latter against the force of said spring body while at the same time squeezing the ring means in response to outward movement of said 25 radially (with the ends of the ring in over 25 first arm; said tubular frame member compris lapping relation) to enter the ring into the open ing an annular skirt surrounding said controlled end of the skirt of the body. As soon as the ring element and said skirt having an annular groove in its inner surface and having radial longitudinal slots intersecting said annular groove for slid has been entered into the ‘skirt, it is retained against expansion by the skirt; the ring and the lever elements are then pressed axially until the ring vreaches the groove 26 and snaps into it. Thereafter, the pin I8 will be prevented from escaping from the bore l6 by engagement of the head of the pin against the short arms 243 of th and a ring in said groove and extending through said bearing holes in said lever elements for rule crumil'lg said lever elements on said frame lever elements. member. ' ably receiving said lever elements; said lever ele ments having transverse bearing holes therein; - As shown in Fig. 1, the plunger I3 of the switch Ill is engaged by the head I 9 of pin 13 and slightly depressed thereby, in which position the contacts 2. A centrifugal actuator of the type described comprising: a tubular frame member supported for rotation about its axis and adapted to be ro of the switch M will be either open or closed tated; a controlled element axially aligned with according to thedesign of the switch. However, 40 said axis and supported for axial movement With when the actuator is rotated above a predeter respect to said frame member; spring means urg mined speed, the centrifugal force developed in ing said controlled member axially in one direc the long arms 23 of the levers 22 throws them tion with respect to said frame member; a plu outwardly as shown in Fig. 2, in which position rality of bellcrank lever elements fulcrumed to the short arms 21% of the lever element's depress said frame member for movement in radial the pin l8, permitting the plunger iii of the planes, each lever element having a ?rst arm nor switch to be lifted by a spring (not shown) With mally extending approximately parallel to said in the switch It and close or open the contacts axis and a second arm approximately normal to within the switch, depending upon the construc the ?rst arm and extending inwardly into engage tion of the latter. Switches of the type shown are ment with said controlled element for moving old and well-known and do not constitute a part the latter against the force of said spring means of the present invention. Preferably, the move in response to outward movement of said ?rst ment of the pin l8 by the lever elements 22 is arm; said tubular frame member comprising an sufficient to disengage the head It of the pin annular skirt surrounding said controlled element from the vswitch plunger i3 so that there ‘is no and said skirt having an annular groove in its friction therebetween during rotation of the ac 55 inner surface and having radial longitudinal slots tuator, after the motor has come up to speed. intersecting said annular groove for slidably re As shown in Fig. 2, depression of the pin i8 ceiving said lever elements; said lever elements and outward movement of the long arms 23 of having transverse bearing holes therein; and a the lever elements is limited by contact between split spring wire ring positioned in said groove the end of the neck 39 of the body at the outer 60 and extending through said bearing holes in said end of bore it and the head it. lever ‘elements for fulcruming said lever elements ‘Various departures from the exact construction on-said frame member; said ring being originally shown can be made without departing from the of larger diameter than said annular groove invention which is to be limited only to the ex whereby it is resiliently retained in said ‘groove. tent set forth in the appended claims. As ex 65 CHARLES E. 'MILLER.