US2432349A

US2432349A - Selective-position control mechanism

Info

Publication number: US2432349A
Application number: US547599A
Authority: US
Inventors: Edward J Stein
Original assignee: Hazeltine Research Inc
Current assignee: Hazeltine Research Inc
Priority date: 1944-08-01
Filing date: 1944-08-01
Publication date: 1947-12-09
Anticipated expiration: 1964-12-09

Description

Dec. 9, 1947. E. J. STEIN 2,432,349

SELECTIVE-POSITION CONTROL MECHANISM Filed Aug. 1, 1944 INVENTOR EDWARD J. STEIN AT RNEY tuning adjustments.

Patented Dec. 9, 1947 UNITED STATES PATENT OFFICE SELECTIVE-POSITION CONTROL MECHANISM I Edward J. Stein, Bellcrose Manor, N. Y.. assignor, by mesne assignments, to Hazeltine Research, Inc., Chicago, 111., a corporation of Illinois Application August 1, 1944, Serial No. 547,599

12 Claims. 1

' This invention is directed to a selective-position control mechanism. While being subject to a variety of applications, the invention is especially suited for controlling the variable element of an adjustably tuned circuit and will be described in ductor and effective to determine the-apparent inductance thereof in accordance with the degree of couplin therebetween. One form of control mechanism, employed to vary the position of the tuning slug and thereby vary the inductance and operating frequency of the tuned circuit, includes a threaded shaft to one, end of which the tuning slug is secured. A control knob affixed to the opposite end of the shaft facilitates accurate While such prior art control mechanisms permit the tuned circuit to be adjusted over a given range of operating frequencies, they generally do not include provisions for arresting the control mechanism at preselected control positions, as is required to adjust the tuned circuit rapidly and accurately to one or more desired operating frequencies within its range. In some installations, such a feature is highly desirable.

Other control mechanisms enabling a tuned circuit to be adjusted over a given operating frequency range and including provisions for rapidly adjusting the circuit to one or more predetermined frequencies within the range have already chanical complexities, these arrangements represent a substantial mass or weight which may be objectionable in applications where the weight factor is important, as in air-borne installations.

It is, therefore, an object of the invention to provide a selective position control mechanism which is not subject to one or more of the abovementioned limitations of prior art arrangements.

It is another object of the invention to provide an improved selective position control mechanism having a simplified and inexpensive mechanical construction.

It is another object of the invention to provide an improved control mechanism which permits f continuous'adjustment of a controlled element,

and includes provisions for quickly and'accuratel'y effecting preselected adjustments of the controlled element. A selective-position control mechanism, in ac-' cordance with the invention, comprisesa rotatable shaft to be coupled to a controlled element for exerting thereon a control effect determined by the angular displacement of the shaft with respect to a reference position and means for angularly displacing the shaft with respect to its reference position. The control mechanism is provided with a first nonresilient stop device including provisions for registering with a second resilient stop device. A second approximately circular stop device is provided in nested relation with the first stop device and comprising a resilient portion including provisions for registering with the first stop device to arrest the shaft in a preselected control position and also including a nonresllient portion. At least one of the first and second stop devices is angularly adjustable to a corresponding preselected position with respect to the above-mentioned reference position independently of the shaft displacement. Additionally, the control mechanism comprises means for supporting the first and second stop devices for relative rotation therebetweenin response to the angular displacement of the shaft and for positioning the stop devices with respect to one another so that upon relative rotation therebetween the registering provisions of the resilient portion of the second stop device exert a locking effect on the first stop device to arrest the shaft in the aforesaid preselected position.

For a better understanding of the present invention, together with other and further objects thereof, reference is had to the following description taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

In the drawing, Fig, 1 is a side elevational view, partly in cross section, of a'control mechanism in accordance with the invention; Fig. 2 comprises a cross-sectional view taken as indicated by directional arrows 2--2 of Fig. 1; while Fig. 8

is an isometric representation of one component of the Fig. 1 arrangement.

Referrirg now more particularly to Fig. 1 of the drawing, there is illustrated a selective-position control mechanism embodying the invention utilized for controlling an adjustably tunedcircuit. The tuned circuit may constitute a component of a wave-signal translating apparatus, such as a wave-signal receiver, but since the invention may be completely understood from a consideration of .the adjustment of the tuned circuit alone, the

thermoplastic resin. The mounting portion 16 4 to a supporting structure. The particular manner in which the tuned circuit is secured to mounting plate 20 will be made clear presently. Considering now the selective-position control mechanism of Fig. 1, the illustrated arrangement comprises a rotatable shaft 25 to be mechanically coupled to the controlled. element, plunger l5, for exerting thereon a control effect determined by the angular displacement of the shaft with respect to a reference position, identified hereinafter. Shaft 25 is rotatable within and supported by an externally threaded bushing 26 which projects through a suitable aperture in mounting plate 20. A flange collar 21 is formed of the coil form has an increased diameter and an internal keyway I1 is milled therein for a purpose to be described hereinafter. A coil-retaining groove II in the form of a continuous spiral is milled into coil form ID and the wall thickness of the coil form is, preferably, as small as practical. The inductor L, per se, consists of a preformed coil having an inner diameter slightly less than the diameter of groove H. The preformed coil is, preferably, made of a resilient 'material such as hard drawn brass, silver plated to have an improved conductivity characteristic. The cross section of the coil conductor and the material from which it is formed are selected.

with reference to the coildiameter so that the free ends l2 and I3 thereof have sufficient selfrigidity to permit direct connection -to other circuit components of the equipment. In assembling the described inductor. arrangement, the preformed coil, is threaded onto coil form It with the convolutions thereof received by groove ii. Due to the resiliency of the coil and the relative dimensions of the coil diameter and groove diameter, the coil convolutions firmly engage groove II and securely lock the coil in a desired position on form l0.

The described tuned circuit is adjustable over a givenrange of operating frequencies through a tuning core or slug M which is freely movable within coil form l0. Tuning slug [4 may be of.

either a magnetic or non-magnetic material, depending upon the variations of inductance required. As is well understood in the art, such inductance of inductor L in accordance with the coupling therebetween. Where the slug is of magnetic material, the inductance increases with this coupling, while the converse effect is obtained through the use of a nonmagnetic mastituting the element controlled by the control mechanism presently to be described.

The tuned circuit L, C is supported by a mounting plate 20 having a right-angle flange portion 2| in which apertures 22 are provided for the purpose of securing the mounting plate 'a tuning slug is effective to vary the apparent integrally on one end of bushing 26 for receiving the mounting portion iii of coil form In, these elements being locked together through one or more machine screws 28.

Shaft 25 is coupled to controlled element [5 through a cam cylinder 30 having a closed end 3! which is fixed to one end of shaft '25. A cam track 32 in the form of an Archimedean spiral is mllledinto the cam cylinder. The end portions of the cam trackare indicated at 32a and 32b. 'The controlled element 15 is received by the open end of cam cylinder 30 and carries a cam-following pin 33 which projects through cam track 32 into engagement with keyway H of the coil form portion l6. Keyway l1 locks pin 33' against rotation while permitting the pin to move in an axial direction. A coil spring 34 interposed between the closed end of cam cylinder 30 and the adjacent end of plunger 15 retains pin 33 incontact with the cam track.

A-control knob 40 secured to the free end of shaft 25 through a set screw 4! constitutes means for angularly displacing the shaft with respect to a reference position. The maximum angular displacement of the shaft is limited to a predetermined value by the engagement of pin 33 with the

end portions

32a and 32b of cam track 32. Cam portion 32a determines the above-men tioncd referenceposition of shaft 25, while the alternate cam portion 32b determines the maximum angular displacement of theshaft. I This maximum displacement in the illustrated arrangement is approximately 360' degrees.

The control mechanism also includes a first non-resilient stop device 43 including provisions for registering with a second resilient stop device. This first stop device comprises a circular member 45 having a hubportion 46 and an annular shoulder 41. Supported upon annular shoulder "41 there is at least one stop projection or element 48 having a wedge-shaped portion 49, Fig. 2, for engaging with a cooperating resilient stop device. Preferably, a plurality of such stop projections 48 are included in device 43 for individually engaging with a cooperating resilient stop device.

A second approximately circular and cooperating stop device 56, represented in Fig. 3, is included in the control mechanism. This stop device comprises a cylindrical member 50 closed at one end and having an arcuate slot 5| extending over a substantial portion of the circumference thereof. Preferably, the slot is milled adjacent to the closed end of the cylinder and extends throughout a major portion of the circumference to provide the second stop device 56 with a L resilient portion 52 and a nonresilient portion 53, The resilient portion 52 includes provisions for registering with the first stop device to arrest shaft 25 in a preselected control position. More particularly, a stop recess 54 is provided in the inner wall of resilient portion 52, having a configuration which is complementary to portion 49 of stop elements 48 included in the first-described stop device 43. This stop recess is effective to register with each of the plurality of stop pro-- jections 48 of device 43 to arrest shaft 25 in a corresponding plurality of preselected control positions.

The control positions of shaft 25 resulting from registration of the stop provisions included in devices 4'3 and 56 may be preselected by arranging at least one of such stop devices or its stop provisions to be adjustable with respect to the reference position of shaft 25 independently of the shaft displacement. For this purpose, stop projections 48 of device 43 are individually adjustable to preselected positions with respect to the reference shaft position. This adjustment is accomplished through machine screws 44 which secure stop projections 48 in adjustably fixed positions upon the annular shoulder 41 of circular member 45. f

The control arrangement is completed into one assembly through means for supportin'g'the described first and second stop devices for relative rotation therebetween in response 'to the angular displacement of the shaft and for positioning the stop devices with reference to, one another so that upon such relative rota-tion resilient portion 52 of the second stop device exerts a greater pressure than the nonresilient portion 53 exerts on the first stop' device; To achieve such a relationship in the supporting and positioning of the first and second stop devices, the closed end of stop'device 56 has an aperture 55 which is offset in the direction of the central portion of resilient section 52. In other 1 words, the radial distance from the center of aperture 55',to the mid-portion of resilient section 52 is less than the radial distance to the corresponding portion of nonresilient section 53. Stop device 56 is, supported by means of aper-. ture 55 upon threaded bushing 26. A look nut 68 engages the threaded bushing and is tightened to clamp the bushing and stop device 56 into one stationary assembly with mounting plate 28;

Suitable spacing washers GI, 62 are includedin device 56. The driving connection to stop device 43 is a transverse pin 63 projecting through hub portion 46 of the stop device and shaft 25. The relative proportioning of the described first and second step devices and the eccentricity of aperture are such that upon relative rotation between the first and second stop devices the resilient portion 52 of the second stop device 55 exerts a greater pressure on the stop projections 48 of first device 43 than is exerted thereon by the non-resilient portion 53 of device 56.

In considering the operation of the described control mechanism, the function of stop members 43 and 58 will inkially be neglected and it will be assumed that contrwgb 40 is adjusted so that pin 33 isin engagemen ith cam portion 32a. As indicated above, this condition reprethe assembly. The second stop device 43, on the other hand, is supported directly" by shaft 25 tobe angularly driven thereby with respect to stop placed in the same sense with respect to its reference position. Such displacement of shaft 25 results in the application of a control effect upon plunger [5 through the agency of cam track 32, pin 33 and keyway H. The control effect manifests itself as a lateral displacement of pin 33, plunger l5 and tuning slug l4, advancing these elements a corresponding amount in the direction of inductor L so as to increase the degree of coupling between the inductor and its tuning slug. The increased coupling results in a decrease in apparent inductance of inductor L and a proportional increase in the operating fro quency of tuned circuit L, C. In the limiting condition when shaft 25 has its maximum angular displacement, the degree of coupling between the inductor andits tuning slug is a maximum and the operating frequency of the tuned circuit likewise has its maximum value. Thus, the control mechanism is effective continuously to adjust a the operating frequency of the tuned circuit L, C over a given range of operating frequencies. Stop

members

43 and 56 permit the operating frequency to be established accurately and rapidly to predetermined desired frequencies within this range in the following manner,

A particular setting of a given stop projection 4'8 of stop device 43 represents a predetermined angular displacement with respect to the reference position of shaft 25. Likewise, a given angular displacement of the shaft represents a given control effect which causes tuning slug i4 to have a predetermined degree of coupling with inductor L resulting in a given operating frequency of the tuned circuit. Therefore, stop projections 48 are adjusted to preselected positions around the periphery of member 45. Having thus selectively positioned stop projections 48, control knob 40 is rotated until a particular stop projection 48 registers with stop recess 54 of resilient portion 52 of stop device 56, arresting shaft 25 in a corresponding preselected control position to establish the desired operatin frequencyof the tuned circuit. Since portion 52 of stop device 56 is resilient, any of stop projections 48 may be rotated beyond stop recess 54 to effect registration of a particular stop device 48 wlth'recess54. Hence, shaft 25 may be arrested in a preselected control position corresponding to the adjustment of a particular. stop projection '48, irrespective of the previous setting of control sents the reference position of shaft 25 in which cam 32 causes tuning slug 14 to be withdrawn from inductor L so as to have substantially zero. coupling therewith. For this condition, the inductor exhibits its natural value of inductance and tuned circuit L, C has its minimum operating frequency. As control knob 40 is rotated in a clockwise direction, shaft 25 is angularly dis- If desired, an additional stop device having the same general construction as device 56 may be included in the control arrangement forcooperation with stop projections 48 of stop device .43. Increasing the stop elements in such a fashutilized to control a variable condenser or any other controlled element.

, The control mechanism of the invention will be seen to comprise a relatively few, light mechanica1 elements. Accordingly, it substantially arrest said shaft in avoids the mechanical complexities of the prior art arrangements mentioned above. Additionally, the control mechanism is inexpensive toconstruct and represents a small mass, renderin it suitable for air-borne installations.

While there has been described What is at present considered to be the preferred embodiment of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein withoutdeparting from the invention, and it is, therefore, aimed in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. A selective-position control mechanism comprising, a rotatable shaft to be coupled to a-controlled element for exerting thereon a control effect determined by the angular displacement of said shaft with respect to a reference position, means for angularly displacing said shaft with respect to said reference position, a first nonresilient stop device including provisions for registering with a second stop device. a second approximately circular stop device in nested relation with said first stop device comprising a re silient portion including provisions for registering with said first stop device to arrest said shaft in a preselected control position and including a nonresilient portion, at least one Of said stop devices being angularly adjustable to a corresponding preselected position with respect to said reference position independently of said shaft displacement, and means for supporting said stop devices for relative rotation therebetween in response to said displacement of said shaft and for positioning said stop devices with respect to one another so that upon relative rotation therebetweensaid registering provisions of said resilient portion of said second stop device exert a locking effect on said first stop device to arrest said shaft in said preselected position,

2. A selective-position control mechanism comprising, a; rotatable shaft to be coupled to a controlled element for exerting thereon a control efiect determined by the angular displacement of said shaft with respect to a reference position, means for angularly displacing said shaft with respect to said reference position, a. first nonresilient stop device including provisions for registering with a second stop device, a second approximately circular stop device .in nested relation with said first stop device comprising a resilient portion including provisions for registering with said first stop device to arrest said shaft in a preselected control position and including a nonresilient portion, at least one of said stop devices being angularly adjustable to a correspondin preselected position with respect to said ref erence position independently of said shaft displacement, and means for supporting said stop devices for relative rotation therebetween in response to said displacement of said shaft and for ccentrically positioning said stop devices with respect to one another so that upon relative rotation therebetween said registering provisions of said resilient portion of said second stop device exert a locking effect on said first stop device to said preselected position.

- 3. A selective-position control mechanism comprising, a rotatable shaft to be coupled to a controlled element for exerting thereon a control effect determined by the angular displacement of said shaft with respect to a reference position, means for anguiarly displacing said shaft with respect to said reference position, a first nonresilient stop device including at least one stop projection for registering with a second stop device, a second approximately circular stop device in nested relation with said first stop device comprising a resilient portion having at least one stop recess for registering with said stop projection of said first stop device to arrest said shaft in a preselected control position and including a nonresilient portion, at least one of said stop devices being angularly adjustable to a corresponding preselected position with respect to said reference position independently of said shaft displacement, and means for supporting said stop devices for relative rotation therebetween in response to said displacement of said shaft and for positioning said stop devices with respect to one another so that upon relative rotation therebetween said stop recess of said resilient portion of said second stop device exerts a locking effect on said first stop device to arrest said shaft in said preselected position.

4. A selective-position control mechanism comprising, a rotatable shaft to be coupled to a controlled element for exerting thereon a control effect determined by the angular displacement of said shaft with respect to a reference position, means for angularly displacing said shaft with respect to said reference position, a first nonresilient stop device including provisions for registering with a second stop device and angularly adjustable to a preselected position with respect to said reference position independregistering with said first stop device to arrest said shaft in a corresponding preselected control position and including a nonresilient portion, and means for supporting said stop devices for relative rotation therebetween in response to said displacement of said shaft and for positioning said stop devices with respect to one another so that upon relative rotation therebetween said registering provisions of said resilient portion of said second stop device exert a locking effect on said first stop device to arrest said shaft in said preselected position.

5. A selective-position control mechanism comprising, a rotatable shaft to be coupled to a controlled element for exerting thereon a control effect determined by the angular displacement of said shaft with respect to a reference position, means for angularly displacing said shaft with respect to said reference position, a first nonresilient stop device including a plurality of stop elements for individually registering with a second stop device and individually adjustable to a preselected position with respect to said reference position independently of said shaft displacement, a second approximately circular stop device in nested relation with said first stop device rotation therebetween said registering provisions of said resilient portion of device successively to arrest said shaft in said plurality of preselected positions.

6. A selective-position control mechanism comprising, a rotatable shaft to be coupled to a controlled element for exerting thereon a control effect determined by the angular displacement of said shaft with respect to a reference position, means for angularly displacingsaid shaft with respect to said reference position, a first nonresilient stop device including provisions for reg istering with asecond stop device, a second approximately circular stop device in nested relation with said first stop device comprising a cylindrical member having an arcuete slot extending over a substantial portion of the circumference thereof to provide a resilient portion and a nonresilient portion and having provisions in said resilient portion for registering with said first stop device to arrest said shaft in a preselected control position, at least one of said stop devices being angularly adjustable to a corresponding preselected position with respect to said reference position independently of said shaft displacement, and means for supporting said stop devices for relative rotation therebetween in response to said displacement of said shaft and for positioning said stop devices with respect to one another so that upon relative rotation therebetween said registering provisions of said resilient portion of said second stop device exert a locking effect on said first stop device to arrest said shaft in said preselected position.

'7. A selective-position control mechanism comprising, a rotatable shaft to be coupled to a controlled element for exerting thereon a control effect determined by the angular displacement of said shaft with respect to a reference position, means for angularly displacing said shaft with respect to said reference position, a first nonresilient stop device including provisions for registering with a second stop device, a second approximately circular stop device in nested relation with said first stop device comprising a cylindrical member having an arcuate slot extending over a major portion of the circumference thereof to provide a resilient portion and a nonresilient portion and having provisions in said resilient portion for registering with said first stop device to arrest said shaft in a pro-- selected control position, at least one of said stop devices being angularly adjustable to a corresponding preselected position with respect to said reference position independently of said shaft displacement, and means for supporting said stop devices for relative rotation therebetween in resaid shaft with respect to a reference position,

means for angularly displacing said shaft with respect to said reference position, a first non resilient stop device including provisions for registering with a second stop device, a second approximately circular stop device in nested relation with said first stop device comprising a cylindrical member closed at one end and having an arcuate slot extending over a substantial pordevices with respect to one another so that upon relative rotation therebetween said registering provisions of said resilient portion of said second stop device exert a locking effect on said first stop device to arrest said shaft in said preselected position.

9. A selective-position control mechanism comprising. a rotatable shaft to be coupled to a controlled element for exerting thereon a control effect determined by the angular displacement of said shaft with respect to a reference position, means for angularly displacing said'shaft with respect to said reference position, a first nonresilient stop device including provisions for reg-' istering with a second stop device, a second approximately circular stop device in nested relation with said first stop device comprising a cylindrical member closed at one end and having an arcuate slot adjacent said closed end extending over a substantial portion of the circumference thereof to provide a resilient portion and a nonresilient portion and having provisions in said resilient portion for registering with said first stop device to arrest said shaft in a preselected control position, at least one of said stop devices being angularly adjustable to a corresponding preselected position with respect to said reference position independently of said shaft displacement, and means for supporting said stop devices for relative rotation therebctween in response to said displacement of said shaft and for positioning said stop devices with respect to one another'so that upon relative rotation therebetween said registering provisions of said resilient portion of said second stop device exert a locking effect on said first'stop device to arrest said shaft in said preselected position.

10. A selective-position control mechanism comprising, a, rotatable shaft to be coupled to a controlled element for exerting thereon a control effect determined by the angular displacement of said shaft with respect to a reference posi-.

tion, means for angularly displacing said shaft with respect to said reference position, a first nonresilient stop device including provisions for registering with a second stop device, a second approximately circular stop device in nested relation with said first stop device comprising a resilient portion including provisions forregistcring with said first stop device to arrest said shaft in a preselected control position and including a nonresilient portion, at least one of said stop devices being angularly adjustable to a corresponding preselected position with respect to said reference position independently of said shaft displacement,- and means for supporting said stop devices so that said first stop device is angularly driven with respect to said second stop device by said shaft and for positioning said stop devices with respect to one another so that upon relative rotation therebetween said registering provisions of said resilient portion of said second stop device exert a locking effect on said first stop device to arrest said shaft in said preselected position.

11. A selective-position control mechanism comprising, a rotatable-shaft to be coupled to a controlled element for exerting thereon a control effect determined by the angular displacement of said shaft with respect to a reference position, means for angularly displacing said shaft with respect to said reference position, a first nonresilient stop device angularly driven by said shaft and including provisions for registering with a second stop device, a second stationary and approximately circular stop device in nested relation with said first stop device comprising a resilient portion including provisions for registering with said first stop device to arrest said shaft in a preselected control position and including a non-resilient portion, at least one of said stop devices being angularlyadjustable to acorresponding preselected position with respect to said reference position independently of said shaft displacement, and means for positioning said stop devices with respect to one another so that upon relative rotation therebetween said registering provisions of said resilient portion of said second stop device exert a locking effect on said first stop device to arrest said shaft in said preselected position.

12. A selective-position control mechanism comprising, a rotatable shaft to be coupled to a controlled element for exerting thereon a control effect determined by the angular displacement of said shaft with respect to a reference 2 position, means for angularly displacing said shaft-with respect to said reference position, a first nonresilient stop device supported by said shaft for rotation therewith and including provisions for registering with a second stop device, a second stationary and approximately circular stop device in nested relation with said first stop device comprising a resilient portion including provisions for registering with said first stop device to arrest said shaft in a preselected control position and including a nonresilient portion, at least one of said stop devices being angularly adjustable to a corresponding preselected position with respect to said reference position independently of said shaft displacement, and means for positioning said stop devices with respect to one another so that upon relative rotation therebetween said registering provisions of said resilient portion of said second stop device exert a locking effect on said first stop device to arrest said shaft in said preselected position.

EDWARD J. STEIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS