US3696713A

US3696713A - Rotary positioner

Info

Publication number: US3696713A
Authority: US
Inventors: Phillip A Ragard
Original assignee: Universal Instruments Corp
Current assignee: Universal Instruments Corp
Priority date: 1970-11-09
Filing date: 1970-11-09
Publication date: 1972-10-10
Anticipated expiration: 1989-10-10

Abstract

A pneumatically operated shaft positioner which has a C-shaped chamber with a rotary vane member responding to differential pressure conditions caused by opening an exhaust port around the periphery of the chamber.

Description

United States Patent Ragard v [54] ROTARY POSITIONER [72] Inventor: Phillip A. Regard, Binghamton,

NY. I

[73] Assignee: Universal Instruments Corporation,

v Binghamton, N.Y.

[22] Filed: Nov. 9, 1970 [21] App1.No.: 87,861

[52] US. Cl ..92/l21, 19/357 [51] Int. Cl. ..F01c 9/00 [58] Field of Search ...92/121, 122; 91/408, 409, 357

[56] References Cited UNITED STATES PATENTS 2,825,307 3/1958 Enyeart ..91l357 3,094,041 6/1963 Wagner ..92/ 122 2,890,889 6/1959 Work "912/ 122 3,411,413 11/1968 MacNeill ..91/357 51 Oct. 10,1972

2,404,262 7/ 1946 Whitfield ..92/121 2,557,912 6/1951 Lane ..92/122 3,063 ,422 1 H1962 Gregowski et a1. ..92/121 2,915,044 12/1959 Nelson ..92/ 121 2,902,009 9/ 1959 Ludwig ..92/121 UX FOREIGN PATENTS OR APPLICATIONS 1,928,749 12/1970 Germany ..91l357 PrimaryExaminerMartin P. Schwadron Assistant Examiner-R. I-I. Lazarus Attorney-Fidelman, Wolffe & Leitner [57] ABSTRACT A pneumatically operated shaft positioner which has a C-shaped chamber with a rotary vane member responding to differential pressure conditions caused by opening an exhaust port around the periphery of the chamber.

7 Claims, 3 Drawing Figures PME'NTEU um 10 um INVENTOR PHILLIP A. RAGARD ROTARY POSITIONER This invention relates to an automatic positioning device which may be adjusted to position a shaft at any predetermined degree of rotation.

One of the requirements arising in various industries is the need to be able to rotate a shaft carrying a tool, instrument, etc., to a desired angular position positively.

The usual approaches to this problem have involved gearing arrangements or directly coupled motors with angular stop means. Numerous problems have been encountered using these arrangements. One problem has been the inability to achieve a positive angular position due to gear tolerances and wear. Another problem has been oscillation of the shaft once it reaches the predetermined position due to play and bounce in the mechanical arrangements. While some pneumatic mechanisms have been tried, they have been unsuccessful.

This invention is directed to a pneumatic rotary vane shaft positioner. The chamber is positioned on the shaft and externally fixed and a vane is securely attached to the shaft for rotary movement within the chamber. A fixed wall is positioned within the chamber also and, with the vane, divides the chamber into two subchambers. Air from one source is admitted into the two subchambers by ports that can be located in the fixed wall or adjacent thereto.

- A series of additional ports are located around the periphery of the chamber. The size of the ports is slightly larger than the width of the vane. The ports are adapted to be opened and closed externally, one at a time. When air under pressure is admitted into the device and one of the peripheral ports is opened, the vane will rotate until it centers on'that port, carrying with it the shaft. Since the port is slightly wider than the vane, willbe allowed to escape and no oscillation of the vane occurs. The air pressure in the subchambers will be equal at this point.

When it is desired to rotate the shaft to a new angular position, the first peripheral port is closed and a second one opened. Again, the vaneand shaft will rotate until it centers on the second port. I

Accordingly, it is one object of this invention to provide a pneumatically controlled shaft positioning mechanism.

It is a further object of this invention to provide a shaft positioning apparatus having a plurality of angular adjustment positions.

It is a still further object of this invention to provide a positive action shaft positioning mechanism with only one moving part.

A further object of this invention is to provide a pneumatic positioning mechanism which will angularly position shafts without any oscillation of the shaft.

These and other objects of this invention will become apparent when taken with reference to the accompanying specification and drawings in which:

FIG. 1 is a perspective view, partially broken away, showing the internal chamber and vane configuration of the positioning mechanism;

FIG. 2 is a plan view of the mechanism comprising this invention;

FIG. 3 is a cross sectional view of the positioning mechanism taken along line 303 of FIG. 2.

tapped bores 107 are aligned to receive machine screws 108.

Plates 102 and 104 are centrally bored at 109 and I 112, respectively, which holes are internally counterbored at 110 and 113 respectively. These counterbored portions receive bushings 111 and 114 which engage shaft 115, adapted to rotate-within housing 101 on bushings.

Mounted on shaft 115 between plates 102 and 104 is a cylindrical vane support collar 116. It has flat end portions 117 and 118 which tightly engage the internal planar faces of plated 102 and 104.

Secured in any suitable fashion, such as by welding to collar 116 is vane 120 which has flat parallel sides 121 and 122 and an arcuate edge portion 123 which, together with the internal configuration of chamber 103, forms a seal making for two variable size subchambers, within chamber 103 in conjunction with a preshaped wall member 124.

Member 124 has radial flat sides 125 and 126 and arcuate outer end 127. It is tapped at 129 to receive the end of a machine screw 129 which passes through hole 131 in housing 101 (FIG. 3) and has a countersunk head portion 130. Screw 129 holds it in place to allow collar 116 to rotate until either side 121 or 122 of vane 120 engages a corresponding side 125 or 126.

There are two air inlet holes 132 and 133 provided in plate 104 adjacent and slightly overlapping sides 125 and 126 of member 124. The holes overlap the sides, as shown in FIG. 2, for the purpose of insuring that vane 120 moves in case it is in the position of abutting member 124. A fitting (FIG. 1) is used to connect inlet tubing 134 to said holes.

Around the periphery of housing 101 are a series of bores, such as 135 in FIG. 3, which receive exhaust port fittings such as 137 and 140 (FIG. 3).

Fitting 137, as shown in cross section in FIG. 3, has a threaded portion 138, a flange portion 136, an intermediate portion 138 and a reduced diameter passage 139. The exhaust fittings may also include a sealing gasket such as 142 which sits under flange 141 of fitting 140.

Plate 104 has lapped holes such as 144 and 145 therein for the, purpose "of securing assembly 100 against rotation with shaft 1 15.

Collar 1 16 is bored at 146 which aligns with hole 148 in shaft 1 15 to receive a press-fitted locking pin 147.

Referring again to inlet ports 132 and 133, it is obvious that they may be provided within member 124 in the general shape of a Y-port.

The operation of the apparatus is simple. Air from the same source, i.e., at the same pressure, is admitted into chamber 103. A particular exhaust valve (any number can be employed) is opened, e. g., port 137 Since port 137 will be in one of the two subchambers created by vane 120 and member 124, the inlet air coming into that subchamber will exit through port 137. Since this will produce less pressure in this subchamber than in the other subchamber, the vane will be forced in the direction of lower pressure. It will continue moving until it reaches port 137. Since the diameter of bore 135 is slightly wider than the arcuate end face 123, the vane will center on the port and air will leak out on either side of the vane 120.

When it is desired to change shaft position, port 137 is closed and another opened. Vane 120 again moves in the same manner.

The assembly 100 can be constructed of any suitable material, such as steel, aluminum, plastic, etc. and may be as large as desired. Naturally, the larger the shaft and the heavier the load, the more air pressure that will be needed.

While only one embodiment of the rotary pneumatic position has been shown and described, it will be obvious to those of ordinary skill in the art that many changes and modifications can be made without departing from the scope of the appended claims.

What is claimed is:

1. A pneumatically operated shaft positioner comprising a housing, a cylindrical chamber within said housing, a rotatable vane means within said chamber, shaft means externally of said housing and in operative relationship with said rotatable vane means, a partition means in said chamber which, with said vane means, divides said chamber into two subchambers which vary in volume depending on the position of the vane means, air inlet means adjacent said partition means and adapted to admit air under equal pressure to either side of said partition means, said air inlet means being sufficiently large to simultaneously overlap a portion of said partition means and entirely overlap said rotable vane means when said rotable vane means is adjacent said partition means in order to insure proper movement of said vane from said partition means, and at least one pressure exit port means of a dimension larger than the width of said vane means so as to allow air to escape said subchambers when said vane means is positioned adjacent said port means by the air pressures in said subchambers.

2. A shaft positioner as in claim 1 wherein there are a series of exit port means in said chamber.

3. A shaft positioner as in claim 2 wherein said series of exit port means are located on the inner peripheral wall of said chamber.

4. A shaft positioner as in claim 2 and including means to open one exit port means and close the other exit port means.

5. A shaft positioner as in claim 1 wherein said chamber means is cylindrical in volume, said shaft means passing through said chamber means and coaxial therewith, a collar on said shaft means, said collar having a vertical height substantially the same as the height of said cylindrical chamber and extending from said collar substantially to the inner periphery of said chamber, said partition means being fixed in position.

6. A shaft positioner as in claim 5 wherein there are a series of exit port means located on the inner peripheral wall of said chamber, each exit port being of a circular configuration, and means to selectively open said exit ports to position said shaft in predetermined angular positions.

7. A shaft positioner as in claim 5 wherein said air inlet means comprises two ports located in said housing ad acent to and overlapping said partition means; an

said ports are sufficiently large to allow air to escape said subchambers when said vane means is positioned adjacent said air inlet ports.

Claims

7. A shaft positioner as in claim 5 wherein said air inlet means comprises two ports located in said housing adjacent to and overlapping said partition means; and said ports are sufficiently large to allow air to escape said subchambers when said vane means is positioned adjacent said air inlet ports.