US3176522A - Self-adjusting switch actuator - Google Patents

Description

April 6, 1965 R. N. QUENNEVILLE ETAL 3,176,522

SELF-ADJUSTING SWITCH ACTUATOR Filed June 25, 1962 INVENTORS R07 0. FISHER RAYMOND N OUENNEV/LLE Br f- AZ/4M ATTORNEY United States Patent "ice 3,176,522 SELF-ADJUSTHNG SWITCH ACTUATQR Raymond N. Quenneville, Granby, and Roy B. Fisher,

East Hartland, Conn, assignors to United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Filed June 25, 1962, Ser. No. 204,962 4 Claims. (Cl. 73-540) This invention relates to actuating devices and more particularly to self-adjusting centrifugally operated devices in high speed rotary mechanisms such as turbine starters and jet engines. Most of the starters are designed with rotor cutout switches which actuate shutoff valves. In other words, these cutout switches are intended to shut off the electrical or pneumatic power supply to the starter. The shutoff system may be of the type shown in US. Patent No. 2,731,980. Starters of this type are shown in Patents Nos. 2,675,708 and 2,721,- 482. These cutout devices are actuated by a centrifugal device which is mounted on a rotary portion of the starter. The actuating switches may be of the type described in said Patent No. 2,731,980 or may be micro switches. Inasmuch as these switches are very sensitive to the relative motion of the actuator, the gap between the actuator and the switch becomes very critical where warpage or manufacture and assembly tolerances must be taken into consideration. According to this invention then, a device is provided which automatically sets itself at assembly and continues to readjust itself during the life of the starter.

These and other objects of this invention will become readily apparent from the following detailed description of the drawing which illustrates the improved actuating device in section and the switch schematic.

Referring to the drawing, a housing is provided which forms a part of the rotary portion of the starter and other similar mechanism. The housing includes a centrally located actuator pin 12 which is intended to actuate a switch 14 by means of an abutment 16.

The housing 10 carries a sleeve 20 which is slidably mounted in a bore 22. The sleeve 20 carries a disc 24 which is axially movable relative to the sleeve 20 and is fastened to a collar 26 fixed to the actuator pin 12. A split ring friction element 30 surrounds the sleeve 20 and is intended to engage the surface of the bore 22. A centrifugally operated ball 32 is carried in the chamber 34 adjacent to the back side of the disc 24 and under centrifugal loading is intended to move radially outwardly and engage the bevel surface 36 on the back side of the disc 24.

During operation then, the centrifugal force moves the split ring 30 radially outwardly so that by friction it prevents movement of the sleeve 20 toward the left. With the sleeve 20 thus fixed, the ball 32 is moved against the bevel surface 36, thereby forcing the disc 24 toward the left against the spring 38. Movement of the disc 24 to the left carries the collar 26 and moves the actuator pin 12 to the left against abutment 16 to trip the switch 14.

I The left-hand end of spring 38 is held in position by an abutment 40 which is connected to the sleeve 20 by threads 44.- The sleeve 20 is also locked to the casing 10 by means of a snap ring 46 having a radially extending lock pin portion 48 whichis permitted relative limited axial movement by means of a slot 50.

To insure the proper gap or null pressure between the actuator pin 12 and the abutment 16, a compensating spring 60 is carried adjacent .to the right-hand end of the pin 12 and the casing 10. The spring 60 will impose a pressure against the backup disc 62 and the disc 36 which is just enough to position the pin 12 in its proper relative position to abutment 16. The tripping device in the 3,175,522 Patented Apr. 6, 1965 switch 14 is normally spring loaded and that tripping device requires slightly more pressure than is capable of being exerted by the backup spring 60. Thus the spring 60 merely serves the purpose of properly positioning all of the parts of the actuator relative to the switch 14 without tripping the latter. When the rotary portion has come to a standstill, the spring 60 adjusts the entire assembly of parts in an axial direction regardless of wear, warpage, and the like.

As a result of this invention, a relatively simple mechanism has been provided whereby a switch actuator may be assembled with ease and which will be continually automatically adjusted throughout its life.

Although only one embodiment of this invention has been illustrated and described, it will be apparent that various changes and modifications may be made in the construction and arrangement of the various parts without departing from the scope of this novel concept.

What is desired by Letters Patent is:

1. An actuator mechanism for actuating a relatively sensitive device by minute movements including an axially movable actuating member, a housing adapted to rotate at relatively high speed, means for driving said housing, means carried by said housing including centrifugally actuating means for moving said actuating member along the axis of rotation, means urging said centrifugal means to an actuator inactive position, spring means operative when the housing is stationary to move said actuator and centrifugal means in an actuating direction without actuating said actuator, and means connecting said actuator mechanism, said driving means for inactivating said driving means upon actuation of said actuator, said urging means comprises an abutment having a central opening receiving said actuating member and a spring retained by said abutment, a sleeve surrounding said abutment and connected to restrict relative rotation therebetween, said sleeve mounted in said housing for limited axial movement relative thereto and centrifugal means engageable with the wall of said housing to prevent axial movement of said sleeve when said housing rotates.

2. A self-adjusting centrifugal switch actuator adapted to continuously engage a switch intended to be actuated comprising a housing adapted to rotate, a sleeve mounted in a bore of said housing and rotatable therewith and movable rectilinearly with respect thereto, an axially movable pin having one end abutting the switch to be actuated centrally mounted in said sleeve, an end wall reciprocally supporting said pin and engaging said sleeve for moving it rectilinearly, a spring adjacent the end wall urging said end wall, said sleeve, and said pin toward the switch intended to be actuated to keep the end of the pin in contact therewith, a centrifugally responsive member mounted in a recess formed in said sleeve adjacent said bore for preventing said sleeve from moving rectilinearly when said housing rotates, and actuating means in said sleeve responsive to the speed of said housing for moving said pin axially for tripping the switch intended to be actuated.

3. Apparatus as defined in claim 2 wherein said actuating means includes a wall member having an inclined surface secured to said pin, a radially movable freernounted member between said wall member and said end wall adapted to bear against said inclined surface for urging said wall member and pin toward the switch intended to be actuated.

4. A self-adjusting actuating mechanism adapted to continuously engage a member intended to be actuated comprising, in combination, a rotatable housing having an axis of rotation, an actuator pin disposed in a recess formed in said housing along said axis of rotation, a sleeve slidablymounted in said recess surrounding said actuator pin and in coaixal relation therewith, a disk disposed be- 2) tween said sleeve and said actuator pin and slidable relative to said sleeve but fixedly secured to said actuator pin, an end wall member connected to said sleeve and abutting said disk disposed in said recess bearing against the end inner surface of said housing, a relatively smaller recess axially spaced relative to said larger recess for receiving a spring bearing against an end surface of said end wall member for urging said end wall member, said sleeve and said disk along the axis of rotation, means movable in response to the rotation of the housing mounted between said end wall and said disk formoving said disk and said actuator pin along said axis or rotation to actuate said member intended to be actuated, and additional means movable in response to the rotation of the housing mounted between the sleeve and an inner wall of the housing in the larger recess for restraining movement of said end wall and said sleeve when said housing rotates.

51; References Cited by the Examiner UNlTED STATES PATENTS 2,168,372 8/39 Tabb 73-537 X 2,341,624 2/44 Kieser 7355l 2,426,840 9/47 Nye 20080 2,575,928 11/51 Preston 200-80 2,598,481 5/52 Young 73 -551 3,008,335 11/61 Banker 7354l FOREIGN PATENTS 420,429 10/25 Germany. 574,893 1/46 Great Britain.

RICHARD C. QUEISSER, Primary Examiner.

ROBERT L. EVANS, Examiner.

Claims (1)

1. AN ACTUATOR MECHANISM FOR ACTUATING A RELATIVELY SENSITIVE DEVICE BY MINUTE MOVEMENTS INCLUDING AN AXIALLY MOVABLE ACTUATING MEMBER, A HOUSING ADAPTED TO ROTATE AT RELATIVELY HIGH SPEED, MEANS FOR DRIVING SAID HOUSING, MEANS CARRIED BY SAID HOUSING INCLUDING CENTRIFUGALLY ACTUATING MEANS FOR MOVING SAID ACTUATING MEMBER ALONG THE AXIS OF ROTATION, MEANS URGING SAID CENTRIFUGAL MEANS TO AN ACTUATOR INACTIVE POSITION, SPRING MEANS OPERATIVE WHEN THE HOUSING IS STATIONARY TO MOVE SAID ACTUATOR AND CENTRIFUGAL MEANS IN AN ACTUATING DIRECTION WITHOUT ACTUATING SAID ACTUATOR, AND MEANS CONNECTING SAID ACTUATOR

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