US2164309A - Shaft-positioning device - Google Patents

Description

J y 1939- A. A. COLLINS 4,

SHAFT POSITIONING DEVICE Filed Dec. is, 1937 s Sheets-Sheet 1' TEL-1 ,9 l .'INVENTOR. (a (90%, 4- v GGA '& 447 .3. J ATTORNEY.

July 4, 1939. H COLLINS 2,164,309

' SHAFT-POSITIONING DEVICE Filed Dec. 18, 1937 I5 Sheets-Sheet 2 s r m /d 2 [5 J I v I a K6 //6z 4 /Ja I /4 INVENTOR.

' BY V ATTORNEY July 4, 3 A. A. COLLINS 2,164,309

SHAFT-POSITIONING DEVICE Filed Dec. 18, 193'! a Sheets-Sheet s I Pour/01v? INVENTOR.

166,661, filed Patented July 4, 1939 UNITED STATES PATENT OFFICE 2,164,309 SHAFT-POSITIONING DEVICE Arthur A. Collins, Cedar Rapids, Iowa Application December 18, 1937, Serial No. 180,658 14 Claims. (Cl. 192-139) My invention relates broadly to apparatus for establishing a rotatable ticularly to a device mounted on a rotatableshaft for coaction with preset relatively fixed abutments.

One application of shaft positioning devices of the type of my invention is in automatic tuning systems for radio apparatus wherein numerous frequency changes over brief periods of time are often required. Arrangements adapted to ten or moredifferent settings form the subject matter of my copending applications, Serial Number 123,453, filed February 1, 1937, for Automatic tuning system and apparatus; Serial Number 172,837, a division thereof filed November 4, 1937, for'Control circuits for signal transmission and receiving apparatus; and Serial Number SeptemberBO, 1937, for Automatic tuning system and apparatus. My present in- 'vention is a departure from the basic principle of the systems shown in these applications, which employ a movable selector stop, and is adapted more particularly to a limited number of settings for more economical and compact installations.

The device of my invention is suitable formanual or automatic operation, and a control system for automatically operating the device of my invention is disclosed in a copending application in the name of Robert E. Samuelson, filed of even date herewith, for Control circuit for shaft positioning system.

One of the objects of my invention is to provide a shaft positioning device having a rotatable stop arm engageable with a plurality of fixed stops in its path.

Another object is to provide a rotatable stop arm cooperative with a plurality of fixed stops, together with means for determining the particular stop effective to establish the stop arm in set position.

Still another object of my invention is to provide a rotatable stop arm having oppositely extending abutments each cooperative with a plurality of fixed stops in an individual plane, together with means for determining which abutment and which particular stop are effective to establish the stop arm in a set position;

A further object of my invention is to provide a rotatable stop arm cooperative with a plurality of'fixed stops, and means controlled by the direction and the degree of rotation of the stop arm for determining which of the fixed stops will be effective to establish the stop arm in set position.

shaft in a plurality of predetermined angular positions and more par- A still further object of my invention is to provide a spring coupled friction clutch device for driving a rotatable stop arm, and means operative by relative movement of the elements of the clutch for determining the operative relation of 5 the stop arm with respect to a multiplicity of fixed stops. I

Still another object of my invention is to provide a friction clutch device for driving a rotatable stop arm, and a differential spiral groove 10 in one of the clutch elements engaged by a pin on the stop arm for radially displacing the stop arm upon relative movement of the elements of the clutch device so that the stop arm is selectively operative with respect to a multiplicity of 15 fixed stops.

Other and further objects of my invention reside in the structure of the device herein disclosed asa preferred form of my invention, as set forth in the following specification with reference to the accompanying drawings, in which: Figure 1 is a side elevational view, with parts broken away and shown in section, of the general'arrangement of my invention; Fig. 2 is a vertical longitudinal sectional view of the apparatus shown in Fig. 1, taken substantially on line 2-2 in Figs. 3 and 5; Fig. 3 is a vertical cross sectional view taken substantially on line 3-3 in Fig. 2; Fig. i is a similar view on line. 4-4 in Fig. 2, looking in the direction indicated; 30 Fig. 5 is a similar view on the same line as Fig.

. 4 but looking in the opposite direction, as indi cated; Fig. 6 is a horizontal sectional view taken substantially on the line 6-45 shown on Fig. 5; Fig. 6A is a View similar to Fig. 6 and showing 35 a modified detail of the structure disclosed; Fig. 7 is a theoretical diagram in linear development 'of the angular displacements of the stop arm,

to rotate each shaft controlling, say, a tuning element of a radio transmitter, until the shaft is restrained from further rotation by some fired 50 interference which is-preset so that the shaft will stop at the desired position independently of any other shafts Simultaneously controlled in a similar manner. In the Autotune systems of my copending applications above noted, several 5 2 adjustable single toothed stop rings are mount ed concentric with the shaft and fixed to it, and one adjustable stop selectively engages any one of these stop rings and determines the limit of rotation and final position of the shaft. An equally effective arrangement may be provided by a single projection. attached to the shaft and selectively engageable with certain fixed stops to limit the rotation of the shaft. In the drawings I have illustrated one arrangement embodying my invention for operation in this manner. Referring to Figs. 1-6, the general construction is as follows:

A driven shaft I is connected with a condenser, variable inductance, switch or other element capable of 360 degrees rotation. The controlled device may be so constructed that two positions in opposite halves of the rotation will give the same effect. For instance, in a variable condenser rotation from a reference zero through 180 degrees'increases the capacity from a minimum to amaximum and further rotation through 180 degrees will decrease the capacity through the same values from maximum to. minimum. Shaft rotates in bearings H and I2, and mounted'concentrically on the shaft is a worm gear H which is rotatable with respect to the shaft l0 but held tightly clamped between clutch plate l and thrust bearing I6 by the action of a coil spring H. The thrust bearing i6 is retained by a collar l9 which bears on a clip |0a secured on the shaft l0. Clutch plate l5 may slide axially on shaft I0 under action of spring H, but will not rotate with respect to it, being keyed thereto as at lb, or otherwise suitably connected with the shaft. Thus, rotation of worm gear M will cause shaft Hi to rotate, through frictional engagement between worm gear I4 and clutch plate |5, unless shaft I0 is forcibly restrained from rotating, in which case worm gear I may continue to rotate, the clutch surfaces slipping.

Parallel to the face of gear M is a stop arm |8 mounted in a wide groove |5a cut in the back of clutch plate l5, as shown particularly in Figs..

3 and 6. The stop arm I! is free to slide in a direction at right angles to the shaft to the extent indicated by full lines and dotted lines in Fig. 3, and the length of slot |8c accommodating the shaft ID. The stop arm is not, however, free to rotate with respect to the shaft, being continuous, with the sides of groove |5a of the clutch plate IS. The ends of stop arm III are formed into oppositely disposed stop lugs I80. and llb (Fig. 2). A pin |2| fixed to stop arm I! extends through a slot lie in clutch plate I! and into a spirally cut groove 24 in gear H, in which it may slide for radially moving the stop arm ll as will be hereinafter more fully described.

Referring to Figs. 2 and 6, the spring I1 is housed in a cylindrical cup 22 closed by a collar 23 which bears on a retaining clip ||lc secured on the shaft I. The base of the cup 22 enters a circular recess lib connected with the groove Jil and bears on stop arm II to press the arm,

the clutch plate I! and driving gear ll into frictional engagement under the action of spring so that all parts are maintained in operable relation. If high spring clutch pressures are required it may be found desirable to relieve stop arm I. of axial pressure, as shown in Fig. 6A, by extending the circular recess lib only part- 1! of the depth of the groove Ha so that the cup 22 bears directly ona portion of the clutch plate l5.

Referring now to Figs. 2 and 4, when gear I and clutch plate |5 are rotating together, there will be. no relative movement between them and consequently no relative movement of pin 2| with respect to the groove 24 in gear I4. 11?, however, clutch plate i5 is restrained from rotating, as by a force at right angles to one end of stop arm I8, and if gear l4 continues to rotate, pin 2| will be constrained to move radially inward or outwardin groove 24, depending in direction on the direction of rotation of gear l4, and in distance on the radial advance'of groove 24.

As indicated in Fig. 1, bearings andv |2 are mounted in a fixed framework 5, (which may be a part of the transmitter framework), which forms a solid support for the bearings'and all of the movable elements. The shape or construction is not important to a description of the principle of this device, except insofar as it provides a mounting for the bearings ii and I2 and the adjusted fixed stops now to be described. 7

As shaft If! rotates with the arm iii in the position as shown in Fig. 3, lug |8a describes an are around the shaft I0. Two stops, designated and 2, are placed across the are described by lug |8a, and in the same plane, so that the motion of lug |8a willbe constrained between these two stops. Then, by making stops and 2 adjustable, over 360 degrees, the are described by lug |8a can be predetermined, and shaft |0 can'be established in either of two predetermined positions by driving worm gear I4 forward or backward through 360 degrees, during which travel projection |8a will stop against adjustable stop I when driven counterclockwise and against stop 2 when driven clockwise, as viewed in Fig. 3.

The system of my invention is adapted to determine any of four positions, provision being made to shift arm l8 so that projection |8b rotates at the same radius that lug |8a did previously. At the same time, projection |8a is drawn toward shaft sufiiciently to clear stops I and 2. Two additional stops, designated 3 and 4, are provided on the are described by lub |8b and in the same plane as lug I8b, which is offset with respect to the plane of lug I811. The shaft may be rotated through an are determined by the stops 3 and l, which also are, adjustable, thus giving two additional setpositions of shaft l0. Lug |8b meets stop 3 in counterclockwise rotation and stop 4 in clockwise rotation as viewed in Fig. 3. To alternate between the first set of stops and 2, and the second set 3 and 4, stop arm I8 is shifted radially by the arrangement best shown in Figs. 2 and 4.

As, shown in Fig. 4, a spiral groove 24 is cut in the face of gear l4 and, during relative rotation between shaft Ill and gear l4, pin 2| which rotates with the shaft slides in this groove. The radial position of stop arm I8 is thus determined by the configuration of the groove 24 and the relative position therein of pin 2|, which deter-.- mines the distance of the pin from the center of shaft Various points on the spiral groove are designated with letters a, b, c, etc., which are likewise employed on the linear development of the groove shown in Fig. '7. Through 360 degrees from b ted the groove does not vary greatly with respect to its distance from the center of shaft l0, and lug |8a will remain in coaction with stop I or 2. In 180 degrees from d to e the groove spirals toward the center sufficiently to bring projection |a out of the line of stops and 2 and to extend projection |0b into the line of stops 3 and 4. Through 360 degrees from e to g, the groove again remains at effectively constant radius from the center, and lug lib may engage stops 3 and 4 with pin 2| anywhere between e and g. The portions of the groove ab and 9-12. are 90 degree extensions for the pin 2| in case mechanical inertia of moving parts causes additional rotation of gear |4 beyond the desired limits, and the extensions may also serve to collect such foreign matter as may be found between the clutch plate i5 and gear I4, or such as may enter through slots lie and |5c. The groove from a to d, and from c to h, is necessarily slightly spiral as it must overlap due to its more than 360 degree length, intersecting portions of the. groove being undesirable.

It will be noted in Figs. 3 and 4, as in Fig. 7

that the 180 portion d-e of the groove has no bearing on the positioning of the stops relative to the groove; for as the pin 2| moves in this portion of the groove, a 180 spacial relation in stops la and |8b offsets themovement of the pinand the effective stop lug appears in the same circumferential position as before. In other words, 180 degrees of the intermediate 360 degrees rotation is employed to move the pin 2| between d and e, projecting the opposite stop lug, while the remaining 180 degrees is employed to bring the pro jected lug around to the position of the retracted lug, but in an offset plane.

For purposes of illustration consider that for engaging stop I or 2, arm |8 will have pin 2| somewhere between points I) and d in groove 24; and for engaging stop 3 or 4, between points e and g; and more particularly, stops I and 4 are limiting stops and the pin 2| will be closest to the limits b and g in the groove 24 when in engagement therewith". The respective ranges-of rotation of gear l4 wherein pin 2| is thus situated, with a reference zero opposite point b, are 0-360, and 720-1080, the range 360-720' being employed as above explained. Taking four desired positionsof the stops to be 90, 170, 200 and 330, and referring to the reference zero opposite b, the stops may be positioned as follows,

counterclockwise from b: stop I at 90; stop 2 at any higher degree position, say 330; stop 3 at the lesser of the remaining degree positions, 170; and stop 4 at the limiting position beyond stop 3, or 260. It will be correspondingly noted that stop I lies clockwise from stop 2 at the position-indicated, and is therefore rightly'in the opposite limiting position. That is to say, stop 2 could not be positioned at 90 and stop I at 330, counterclockwise from b. The stops are shown in Fig. 3 substantially in the positions given, and it will be noted that stops and 2 are engageable within the initial 360 rotation of gear l4, whereas a basic 720 rotation of gear I4 is required before stop 3 or 4 may be encountered.

It might be noted that another arrangement for the stops for the above positions might be: stop I at 90, stop 2 at 170", stop 3 at 260, and

stop 4 at 330, which would be the usual orderly arrangement; or the set-up might be: stop I at 90, stop 2 at 260, stop3 at 170, and stop 4 at 330, the limiting requirements being maintained in everysuch instance.

Asexamples of the operation of the device, the

changes between several possible positions will be 1 considered, attention'being directedto Figs. 3, 4,

7 and 8, in particular. vIn the position correspending to a position #1, arm I! is in the position shown in Fig. 3, lug Ila abuts stop 3 and pin 2| is in the groove between b and c, ati, Fig.

4. If it is desired to shift to a position #2, de-

termined by the abutment of projection Ila against stop 2, worm gear I4 is rotated in a clockwise direction through 360 degrees, pin 2| possibly moving from b to d, b constituting a reference zero as indicated in Fig. 7. During the first part -of the rotation, clutch plate I5 will not move with respect to gear I 4 and projection Ila will move around toward stop 2. When stop 2 is met by projection I8a, pin 2| will follow the groove 24 during the remainder of the 360 degrees rotation,

moving-radially inward slightly due to the small radial displacement of the groove in the remaining degreesof rotation. Pin 2| will come to rest in the are between 0 and d, at k, Fig. 4.

I8 is thus moved so as to draw lug |8a toward the center and remove it from engagement with stop 2,at the same time extending lug |8b away from the center and into the line ofstops 3 and 4. When lug |8a has been removed from engagement with stop 2, and during the final 360 degrees of rotation of gear. l4, arm I 8 and shaft l0 rotate again with gear l4 until lug lllb comes in contact with and is stopped by stop 4, with pin 2| at m, Fig. 4, whereupon shaft |0 will be in its position #4.

In order to shift from the position #4 (established by 1080 clockwise rotation of gear l4 from previous position #1) to position #3, reverse or counterclockwise rotation of gear i4 through 360 is required, during which time stop lug |0b is stopped by stop 3 in the same manner as where a shift is made between positions #1 and #2 with stop lug lBa extended. Pin 2| is then at n. Fig. 4. To return to position #1 from position #3, gear I 4 is rotated 720 degrees in a counterclockwise direction with lug lab against stop 3 until action of pin 2| in groove 24 during the first 360 degrees of rotation withdraws lug |8b from engagement with stop 3, and again extends lug lfla so that it may on further rotation engage stop I.

The transfers in position in the cycle above .described are represented linearly in Figs. 8 and 8A, together with similar diagrams of the further transfers possible. Thus, transfer between positions #1 and #2, or between positions #3 and #4, is accomplished by 360 degree rotation of gear 14, in the proper direction during which period shaft 0 rotates between the positions determined by the extended lug, |8a or IBb, operating between the two stops in its plane. .Shift from position #2 to position #4, as from position #3 to position from position #1 to position #3, or position #4 to position #2; that is, shift must be made to the opposite limiting position followed by return to the desired position. To effect the last operations noted, gear I4 is rotated 1080 degrees'in the required direction and reversed for 360 degrees further rotation, as indicated on the respective diagrams in Fig. 8.

Stops l-l are so constructed that a direct endwise force from lug I811 or b, or the force of Na or b revolving in an, opposite direction to that which would bring it in contact with the stop face, will displace the stop so that the movement of arm II is not'hindered. This allows radial displacement of arm I! regardless of the relative positions of the stops. For example, after stop 'lib has been extended by rotation of gear H with lugs "a against stop 2, it might be in such a position as to have to pass stop 3 before reaching stop 4, the above provisic a taking care of this. Similarly if stop 3 or 4 is directly opposite stop 2, projection of lug lib radially outward against the stop results in displacement of the stop. The arrangement shown in the drawings, particularly Figs. 2 and 3, is intended to be illustrative, merely, of one type of structure having the functions noted. As shown, the stop I, for example, is supported in a housing 6 enclosing a spring I mounted between the stop I and the back cover 6a of the housing. The stop and housing assembly is mounted on a circumferential angle support 8 fixed to the framework 5, as shown. The housing 8 has a bifurcated portion 6b extending therefrom for engaging the'ring member 8, and a clamping-screw 9 for holding the stop in adjusted position. Recalling that stops 3 and 4 are disposed in an offset plane with respect to stops l and 2, this is provided for in the extended bifurcated portion 6b of the mounting means for stops 3 and 4, as illustrated in Fig. 2 at stop 4.

I have illustrated my invention in certain preferred embodiments of the various features thereof, but I do not intend to be limited thereto as I am aware that modifications may be made in the form and arrangement of the elements disclosed without departing from the subject matter of my invention. I desire it understood therefore that no limitations upon my invention are intended except as are imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows: 1. A shaft positioning device comprising a shaft, a driving clutch member rotatably mounted on the shaft, a driven clutch member slidably and non-rotatablymounted on the shaft in frictional engagement with the aforesaid member, a stop arm mounted fol-rotation with and radial displacement with respect to said driven clutoh member, fixed stops cooperable with said stop arm, and means for interconnecting said stop arm and said driving clutch member for radially displacing said stop arm from engagement with one of said stops upon relative movement of said stop arm and said driving clutch member, said stop arm being held againstrotary movement by engagement thereof with the said one of said stops, the aforesaid means including means for maintaining said stop arm in radially displaced position.

2. A shaft positioning device comprising a shaft, a driving clutch member rotatably mounted on the shaft, a stop arm non-rotatable and radially displa'ceable with respect to the shaft, a plurality of fixed stops cooperable with said 3. A shaft positioning device comprising a shaft, a driving clutch member rotatably mounted on the shaft, a stop arm non-rotatable and radially displaceable with respect to the shaft and having oppositely disposed stop lugs thereon extending axially from the arm on opposite sides thereof and movable in separate planes offset from each other, a pair of fixed stops cooperable with each of said stop lugs in the respective plane of movement, one or the other of said lugs being engageable with the respective cooperable stops depending upon the radial position of said stop arm, and means for interconnecting said stop arm and said driving clutch member for radially displacing said stop arm upon' relative movement of said stop arm and said driving clutch member, said stop arm being held against rotary movement by engagement of one of the lugs with a cooperable fixed stop, said radial displacement of said stop arm being effective to retract the said lug from engagement with the said cooperable stop and to project the opposite lug for engagement thereof with one of the fixed stops individually cooperable therewith.

4. A shaft positioning device comprising a shaft, a driving clutch member rotatably mounted on the shaft, a driven clu'tch member slidably and non-rotatably mounted on the shaft in frictional engagement with the aforesaid member, a stop arm mounted in a radial slot in said driven clutch member and radially displaceable with respect thereto, stop lugs carried by said stop arm on opposite faces thereof and movable in separate planes offset from each other, a pair of fixed stops cooperable with each of said stop lugs in the respective plane of movement, said stop lugs being adapted for individual operation with respect to fixed stops for positioning said shaft, and means for interconnecting said stop arm and said driving clutch member for radially displacing said stop arm upon relative movement of said driven and said driving clutch members whereby one or the other of said stop lugs is shifted to effective position for engagement with its respective fixed stops.

5. A shaft positioning device .comprising a shaft, a stop arm non-rotatably mounted on said shaft, a pair of fixed stops engageable by said arm in opposite directions of rotation, means for displacing said arm radially with said arm in engagement with one of said stops, and means for maintaining said arm in radially displaced position.

6. A shaft positioning device comprising a shaft, a stop arm non-rotatably mounted on said shaft and having a pair of selectively projectible stop lugs, fixed stops cooperable with each of said stop lugs; and means for projecting the'one and simultaneously retracting the other of said stop lugs for engagement by the projected lug of one of the fixed stops cooperable therewith for establishing the shaft in desired position.

7. A shaft positioning device comprising a shaft, friction clutch means for rotating said shaft including a driving and a driven member,

trollable thereby upon memos and means, including a stop element operably connected with said driving member and condriving and said driven said'shaft in either of ance with a selected operation of said driving member in a given direction.

8. A shaft positioning device comprising a two positions in 'accordshaft, friction clutch means for rotating said shaft including a driving and a driven member,

Qan'd means, including a stop element operably said driving mem establishing said shaft in connected with saiddriving member and controllable thereby upon relative movement of said driving and said driven members, forestablishing said shaft in a desired position by selected predetermined periods of operation of said driving member in reverse directions.

9. A shaft positioning device comprising a shaft, friction clutch means for rotating said shaft including a driving and a driven member, a radially displaceable stop arm carried by said driven member and having a pin extending axially therefrom, said driving member having a spiral groove in one face thereof for receiving said pin, said groove having an eccentric spiral portion adapted to displace s'aid stop arm abruptly. in radial position upo'n relative move- .ment of said pin in the said portion of said groove, and means'including said stop arm for selected positions in accordance with predetermined degrees and directions of rotation of said driving member.

l0. A shaft positioning device comprising a shaft, friction clutch means for rotating said shaft including a driving and a driven member, r having a spiral groove in one face thereof comprising a 360 portion of small radial displacement connected with a 180 portion of substantial radial displacement connected with a second 360 portion of small radial displacement, a radially shiftable stop arm carried by said driven member and having a pin placed 180 7 portion of said groove.

stop arm for establishing said shaft in selected extending axially therefrom into said groove, said stop arm having a pair of stop lugs discircumferentially; a pair of fixed stops individually cooperable with each of said lugs, one of said lugs being projected and engage able with the respective fixed stops with said pin in the first said 360 portion of said groove and the other of said lugs being similarly operative with said pin-in the said second 360 portion of said groove, said arm being radially shifted upon relative movement of said pin in the said 180 and means including said relative movement of said members, for establishing predetermined period of ing member secured to casing in engagement positions in accordance with predetermined de grees and directions of rotation of said driving member.

11. A shaft claim 10 wherein said driving member has extensions of said groove at either end thereof connected with said 360 portions to provide overrun paths for said pin.

12. In a shaft positioning device, a shaft, friction clutch means for rotating said shaft including a driving and a driven member, said driven member being slidably and non-rotatably mounted on said shaft and having a radial groove therein adapted -to receive a stop arm rotatable with said driven member and radially displaceable with respect thereto, and means for. mounting said members in frictional engagement comprising a thrust bearing for supporting said driving member secured to said shaft, spring pressure means bearing on said arm, means on said shaft for engaging said spring pressure means, said driven member having a circular coaxial cut-out portion coextensive in depth with the radial groove therein for guiding said spring pressure means.

13. In a shaft positioning device, a shaft, friction clutch means for rotating said shaft including a driving and a driven member, saiddriven member being slidably and non-rotatably mounted on said shaft and having a radial groove therein adapted to receive a stop arm rotatable with said driven member and radially displaceable with respect thereto, and means for mounting said members in frictional engagement cbmprising a thrust bearing for supporting said drivsaid shaft, said driven member having a circular coaxial cut-outportion forming a shoulder of said radial groove above the face of said stop arm in said groove spring pressure means seated on said shoulder, and retaining means on said shaft for engaging saidspring pressure means, said stop arm being freely displaceable radially in said groove.

14. In a'shaft positioning device, a shaft, friction clutch means for rotating-said shaft including a driving member spring pressed means for maintaining said membearing for supporting said driving member and a coaxial coil spring mounted in a cylindrical with said driven member, closure means for said casing and retaining means on said shaft for maintaining said coil spring under pressure.

. r A. COLLINS.

and retaining and a driven member, and

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