US2818538A

US2818538A - Motor control system

Info

Publication number: US2818538A
Application number: US549909A
Authority: US
Inventors: Kamen Ira; Joseph B Cejka
Original assignee: General Bronze Corp
Current assignee: General Bronze Corp
Priority date: 1955-11-30
Filing date: 1955-11-30
Publication date: 1957-12-31
Anticipated expiration: 1974-12-31

Description

Dec. 31, 1957 1. KAMEN ET AL 2,818,538

MOTOR CONTROL SYSTEM Filed Nov. so, 1955 2 sheets-sheet 1 UNO@ IN VEN TORS /A KAME/V ./JEH 5.- CE1/KA Dec. 31, 1957 '1. KAMEN ET AL MOTOR CONTROL SYSTEM 2 Sheets-Sheet 2 Filed Nov. .'50, 1955 FIG. 3.

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United States arent Utilice 25,8%,538 Patented Elec. 31, i957 MOTOR coNrRoL SYSTEM Ira Kamen, New York, N. Y., and Joseph E. Cejlra, Highland Park, N. J., assignors to General Bronze Corporation, Garden City, N. Y., a corporation of New York Application November 30, 1955, Serial No. 549,9(l9 13 Claims. (Cl. S18-31) This invention relates to automatic control of electric motor-driven devices. The invention provides a driving means which may be manually preset for driving a movably mounted member to any desired position, and which, without further attention on the part of the operator, will automatically effect movement to the desired position and shut itself oit.

This application is a continuation-in-part of our pending application Serial No. 505,879, tiled May 4, 1955, now abandoned.

While the invention is shown and described herein as applied to a remotely controlled rotator for television receiving antennas, it will be readily understood that the invention is equally applicable to either locally or remotely controlled drive of any kind of member mounted for either rotational or translational movement.

ln television reception, particularly in rural areas where the only television signals which are consistently received emanate from Several different cities at considerable distances from the receiving location in widely divergent directions, it has become desirable or even necessary, in order to enable reception of signals on more than one television channel, to provide for rotation of the receiving antenna to the directions of the various television transmitters.

Most previous antenna rotators have been of the manually-controlled type, having, for example, two pushbutton switches for rotation of the antenna in one direction or the other as desired. Since such antenna rotators usually employ very inexpensive and low-powered electric motors which are geared down at a very high ratio in order to provide the power necessary to drive the antenna, they have been capable of rotating the antennas only at comparatively slow speeds of the order of one revolution per minute or even slower. Since the operator has had to hold the control switches in the actuated position during the entire time the antenna is rotating, he has had to waste considerable time in changing the direction of the antenna. Moreover, because of the human element involved, there was no assurance that the antenna would be rotated to the same position each time it was desired to receive signals from a certain television transmitting station. This has made reception unpredictable and often unsatisfactory. These various factors have created no little resistance to sales of manually-controlled rotators and a substantial demand for an automaticallycontrolled rotator.

There has been at least one type of automaticallycontrolled antenna rotator placed on the market. This rotator includes a multi-contact rotary switch which is preset in accordance with the desired rotational position of the antenna. One of the more obvious defects in the use of this type of automatic rotator is the tact that only a limited number of rotational positions is possible. Where multi-element fringe area television receiving antennas having narrow beam width eld sensitivity patterns are employed, it is sometimes impossible to achieve satisfactory reception unless a much liner control of the antenna position is possible.

The present invention provides a practical automatic rotator which is capable of accurately rotating an antenna to any preselected direction. This is accomplished by the use of an electrical meter movement connected in series with a potentiometer mechanically coupled to the antenna so that the meter needle moves in accordance with the position of the antenna. The path of the needle passes between a small incandescent lamp and a photosensitive cell which are mounted for movement to various positions corresponding to the desired rotational positions ofthe antenna. The photocell is connected in circuit with a relay which controls the supply of current to the rotator motor. When the device is turned on and preset, the antenna will rotate until the needle intercepts the light rays passing from the lamp to the photocell, deenergizing the relay and stopping the motor with the antenna in the desired position.

In one embodiment, a Second needle on the same meter movement cooperates with a graduated scale on the front panel of the control box to visually indicate the position of the antenna at all times during operation. In another embodiment, a single-needle meter movement is employed, but the needle is bent at right angles to provide two portions one of which cooperates with the graduated scale and the other of which intercepts the light beam to the photosensitive cell.

A reversing switch, arranged to be actuated by the antenna at either extreme of its approximately 360 degrees of rotation automatically reverses the connections to the motor when the antenna reaches the end of its travel in either direction. A separate manual switch is provided so that the rotator may be controlled manually if desired. The power for the television receiving set may be drawn through the antenna rotator control box and a thermostatic switch provided to turn on the antenna rotator whenever the television set is turned on and to turn it off automatically when the television set is not in use.

In the drawings:

Figure l is a schematic diagram of the electrical circuit of an antenna rotator embodying features of the present invention.

Figure 2 is a somewhat diagrammatic perspective View of the arrangement of the meter needles and of the lamp and photocell, with certain parts brolren away to reveal their internal construction.

Figure 3 is a schematic diagram of the electrical circuit of an antenna rotator constituting a modied embodiment of the invention.

Figure 4 is a somewhat diagrammatic vertical sectional view of the modied rotator, the circuit of which is shown in Figure 3.

Each of the two types of rotator shown in the drawings is divided into two separate units: a motor unit, generally indicated 1t) (see Figure 1), which is mounted at the base of the mast m which supports the antenna a; and a control box, generally indicated 12, which is mounted in a remote location, for example adjacent the television receiver, the two units being interconnected by means of a live-conductor cable generally indicated 14.

The motor unit 10 suitably may be ofthe type disclosed in the copending application Serial No. 506,847, tiled May 9, 1955, although it is equally useful with many other types of motor units presently in commercial sale. The motor unit shown in said copending application includes an elongated housing having at its upper and lower ends bearings for rotatably supporting a hollow torque tube. This torque tube is coupled to the driven by an electric motor contained in the housing through a speed-reducing gear train which preferably includes slepen 3 a worm gear and worm wheel so that the torque tube cannot be rotated by external forces. The torque tube receives the lower end of the antenna mast and at its upper and lower ends is provided with inwardly projecting bolts for securing the mast.

In the rotator shown in Figures l and 2, the control box 12 is provided with a conventional two-prong male plug 16 for connection to a source of alternating current power, for example at ll volts, 60 cycles. The control box is also provided with a two-prong female receptacle 18 into which the power cord of thel television reeciver may be plugged. Thetwo contact members ofy this receptacle 18 are respectively connected to the two terminals 20 and 22 of the power source, one of these connections being through a bi-metallic element 24a of a thermostatic switch generally indicated 24. When the television set is turned on, it 'draws current through the bi-metallic element 24a, healing and distorting it and causing it to move into engagement with a lixed contact 24b, which is thereby connected to the terminal 20 of the power source.

This fixed contact 24h is connected to one terminal 26a of the primary windingl of a motor transformer generallyindicated 26 and to one terminal 28a of the primary winding of'a lamp transformer generally indicated'28. The other primary terminals 26h and 28b of these two transformers 26 and 28 are connected to each other and to one contact 30a of a momentary contact, single-pole, single-throw, push-button switch 30, the other contact 3011 of which is connected to the other terminal 22 of the power source. Thus, whenever the television set is operating, and when the switch 30 is closed, power is supplied to the primary windings` of the transformers 26and 28.

The secondary winding of the transformer 28k is adapted toprovide an alternating current voltage of approximately 6:3 volts and the two terminals 28e and 28d of this winding are connected across a miniature incandescent lamp 32, for example a bulb having a two-candlepower filament in a self-focusing lenticular envelope.

The primary winding of the transformer 28 is in elfect an auto transformer, being provided with a third terminal 28e which is connected to one terminal of a photosensitive cell 34. The other terminal of the photocell 34 is connected through the winding 36aof a relay generally indicated 36 (which suitably is of the sensitive A. C. type having a winding impedance of approximately 5.0,'000v ohms) and through a pair of normally closed lflxed contacts 40a and 42a, respectively, of a pair of manually-operable switches generally indicated 40 and 42, to the terminal 22 of the power source. The ratio ofV turns in the primary of the transformer 28 is such that across the terminals 2811 and 28e there is developed zlinxIa/ltersnating current voltage of the order of 150 volts The photocell 34 may suitably be one ofthe miniature cadmium sulde cells now commercially available. These ,cells have a static resistance of the order of several hundred megohms, but when light impinges upon them, theirresistance drops to a value less than 100,000 ohms. Thus, when light from the lamp 32 strikes the photocell 34, the resistance of the cell drops to suchvalue'as to permit a minimum of approximately one milliampere of alternating current to flow through the cell 34 and through the winding 36a of the relay 36.

This current `tiow is sufficient-t0 energize the relay 36 and,` close its normally open contacts'36b and 36e. These contacts 36h and 36e are connected across the contacts `30a and 30h of the switch 30 and accordingly serve,las holding ,contactsto maintain the supply of current to the` primariesL ofthe-transformers 26a11d28v even after the momentary contactswitch 30'is opened, so long as light from the bulb 32,reaches the-photocell 3 4,` assuming,r of course, that the televisionsetl remains on and that the manually-operable switches 40 and 42 are not actuated to open their normally-closed contacts 40a and 42a.

The lamp 32 and the photocell 34 are mounted on opposite sides of the path of one of the two needles 44a of a special double needle meter movement 44. One terminal 44b of the meter coil is connected to the junction of a xed resistor 46 :and a potentiometer 48 in a voltage divider circuit which alsoincludesa fixed resistor 50 and which is connected in series with the thermostatic switch 24 across the terminals 2'0 and 22 of the power source. The other terminal 44e of the coilof. the. meter movement 44 is connected through one terminal 52d of a terminal board 52 on the control box, one of the conductors in the cable 14 and one of the terminals 54d on a similar terminal board 54 on the motor unit to the rotary contact 56a of a potentiometer 56 mounted within the motor unit. One end of the resistive winding of this poentiometer 56 is connected through terminals 54e and 52e` with the junction point of the resistor 46 and the potentiometer 48 in the voltage divider network previously described. It will thus be seen that an A. C. voltage whose amplitude depends on the setting of the potentiometer 48 is impressed across the coilof the meter 44 and the potentiometer 56 in series.

Thepotentiometer 56 is mechanically coupled to the antennatfor example, by means ofthe torque'tube previously referred to) so that its rotary contact 56a is moved along the resistance winding of the potentiometer in accordance with the rotational position of the antenna.

The second needle 44d of the meter movement cooperates with a graduated scale 58 which is visible from the front panel of the control box and which is graduated to indicate compass direction.

The circuit constants are so chosen'and the potentiometer 48 in the voltage divider circuit is adjusted so that the voltage impressed across the meter 44 and the potentiometer 56 in series is such that when the antenna. is at one extreme of its rotation, the meter needle 44d is at one end of the scale SSIand when theantenna is at theother extreme of its rotation, the needle 44d is at the other end of the scale. The potentiometer 56 has a special logarithmic taper which makes the calibration of the scale 53 substantially linear.

v As-shown in Figure v2, the lamp 32.and1photocell 34are mounted ,respectively-fin.housings60 and 62 spaced apart ashortdistancexto permit lthe needle 44a of the meter 44 to pass between the two housings.

with narrow slits 60a and I62a ,which are centered on the optical -axis `of the lamp 32 and photocell34 and which are radial with respect to the axis of the meter movement 44 so that they are parallel vrwith the needle 44a when the needle is between. the slits; The slits are `narrowerthan the needle (e. g., .025 wide) ;so that when the needle is aligned with the slits, it cuts off alloffthe light passing from the lamp 32 to the photocell 34.'

The two housings 60'and 62 are secured at the upper end of a bracket64 which is mounted for rotation about an axis which coincides with the axis ofrotation ofthe

needles

44a and 44d. This bracket 64 has at its lower end a sector gear 64a which meshes with a pinion 66 fixed on the rear end of a shaft 70 which projects through the front panel of the control box and carriesat its outer'end a control knob 68. By rotation of the k'nob 68, the lamp 32 and photocell 34 may thus be moved to any rotational position within the range of the needle 44a. The bracket' 64 has mounted at its forward end an indicator Vneedle 64b which also cooperates vwithV the meter scale 58 -to indicate the rotational position for'whichthe control circuit'has been set by the knob 68.

The shaft' 70 of the control 'knob 68'includes aspring loaded friction brake 72, so that the knobrnust be depressed `before llt-may-be rotated. The shaft"70 also has At-their proximate faces, the housings 60-and 62 are respectively provided mounted on it a cam 74 which cooperates with the actuating push-button of the aforementioned momentary contact switch 30, so that the switch 30 is automatically closed each time the control knob 68 is rotated.

One terminal 26a of the secondary winding of the motor transformer 26 is connected through a terminal 52C on the terminal board 52, one of the conductors of the cable 14, and a terminal 54C on the terminal board 54 to a common terminal 76 of the two

windings

78 and 80 of the antenna driving motor 82. The remaining terminals 78a and 80a of these two motor windings are respectively connected to the two fixed contacts 84a and 84h of a single-pole, doublethrow reversing switch generally indicated 84 which is mounted within the motor unit. The movable contact 84C of the reversingy switch 34 is actuated by movement of the antenna (for example by a lug mounted on the aforementioned torque tube), the switch being actuated in one direction at one end of the rotation of the antenna and in the opposite direction at the opposite end of the rotation of the antenna, and being arranged so that the antenna is permitted rotation through an angle slightly in excess of 360 degrees, for example 365 degrees. The movable Contact 84C of the reversing switch 84 is electrically connected through a terminal 54e on the terminal board 54, one of the conductors of the cable 14, a terminal 52e on the terminal board 52 and through a pair of normally closed contacts 4Gb and 42b of the aforementioned manuallyoperable switches 40 and 42 with the other terminal 26d of the motor transformer 26.

Thus, assuming the manuallynoperable switches 40 and 42 are in their normal position, as shown, energization of the primary of the motor transformer 26 will cause one or the other of the motor windings 7S or 80 to be energized depending upon which of the contacts 84a or 84h of the reversing switch 84 is closed. When the winding 78 is energized, the motor will rotate the antenna in one direction, and when the Winding 80 is energized the motor will rotate the antenna in the opposite direction. A ca pacitor 86 is connected across the motor windings 7S and S in conventional fashion.

The

windings

78 and 80 may also be energized by actuation of the manual switches 40 and 42, respectively. The common terminal '76 of these two windings is always connected to one terminal 26C of the secondary of the motor transformer 26. The other terminal 78a of the winding 78 is connected through a terminal 54a on the terminal board 54, one of the conductors of the cable 14, and a terminal 52a on the terminal board 52 to a fixed contact 40C in the switch 40. The switch 40 is a double-pole, doubleethrow switch wherein the contacts 4012 and 40C cooperate with a movable contact 40d which is connected to the aforementioned fixed contact 42b in the switch 42. The switch 42 is a similar double-pole, double-throw switch wherein the xed contact 42b as well as another xed contact 42o cooperate with a movable contact 42d which is connected to the aforementioned terminal 26b of the motor transformer 26. The Xed contact 42C is connected through a terminal 52b on the terminal board 52, a conductor in the cable 14, and a terminal 54b on the terminal board 54 to the aforementioned terminal 80a of the winding 80. It will thus be seen that actuation of the switch 4i) to throw the movable contact 40d into engagement with the fixed contact 40C will energize the winding 78 through the contacts 40e and 40d of switch 40 and the contacts 42b and 42d of switch 42. lt will also be seen that actuation of the switch 42 will energize the winding Sil through the contacts 42e and 42d of the switch 42.

Actuation of either of the switches 40 or 42 also connects the primaries of both the motor transformer 26 and the lamp transformer 28 with the power source through the following circuit: The terminals 26b and 2817 of these two transformers are connected by means of a conductor 88 with a fixed contact 40e in the switch 40 and a xed contact 42e in the switch 42. The fixed Contact 40e, along with the aforementioned fixed contact 40a, cooperates with a movable Contact 40)c of this single-pole, double-throw section of the switch 40. The fixed contact 42e, along with the aforementioned xed contact 42a of the switch 42, similarly cooperates with a movable contact 42]c of the switch 42. Actuation of the switch 40 thus connects the terminals 26b and 28b of the transformers 26 and 28 to the terminal 22 of the power source through contacts 40e and 40j of switch 40, and contacts 42a and 42j of switch 42. Actuation of switch 42 connects these transformer terminals 26b and 28h to the terminal 22 of the power source through contacts 42e and 42j of switch 42. The other terminals 26a and 28a of these transformers are connected to the other terminal 20 of the power source through the thermostatic switch 24, as previously described. Thus, actuation of either of the switches 4i) or 42 performs the following functions: (l) it energizes the primaries of both the motor transformer 26 and the lamp transformer 28; (2) it connects the secondary of the motor transformer 26 to one or the other windings of the motor 82 to cause the antenna to rotate in the desired direction; and (3) it opens the circuit to the winding of the relay 36 and renders the automatic control circuit inoperative.

The switches 40 and 42 advantageously may be respectively arranged for actuation by rocking in opposite directions of a single, centrally-pivoted bar mounted at an accessible location on the control box.

The operation of this apparatus may be summarized as followsrWith the plug 16 plugged into the outlet of a source of A. C. electrical power, and with the television receiver plugged into the receptacle 18, whenever the television receiver is turned on, the thermostatic switch 24 will be closed. lf the operator desires to rotate the antenna under a manual control, he may depress the switch 40 for rotation in one direction and the switch 42 for rotation in the opposite direction. The antenna will rotate in the desired direction until the end of its permissible travel is reached when a lug on the torque tube comes into engagement with a stop on the housing of the motor unit. rThe motor is of the type which draws only slightly more current when stalled than when rotating so that cutout switches to disconnect the motor at each end of its rotational movement are unnecessary.

As the antenna rotates, the movable arm 56a is moved along the resistive winding of the potentiometer 56, causing the

needles

44a and 44d of the meter 44 to move in accordance with the changing position of the antenna. The operator may either observe the antenna itself and rotate it until the desired direction is achieved, or he may observe the screen of the television set and rotate the antenna until the best reception is obtained. After a brief initial period of experimentation, the operator will determine the best rotational position for each of the television stations whose signals are regularly received in his location, and he may make notations of the antenna headings, as indicated on the scale 58 by the needle 44d of the meter 44, or may merely mark these locations directly on the scale 58.

Once the optimum rotational position has been ascertained for each transmitting station, the operator will probably prefer to use automatic control. In order to set the control box for automatic rotation to a desired position, the operator depresses the knob 68, releasing the brake 72 and closing the switch 30. This energizes the primaries of the transformers 26 and 28 and illuminates the lamp 32. lt also impresses a voltage across the photocell 34 and the relay 36 in series. As light from the lamp 32 impinges upon the photocell 34, the winding of the relay 36 will be energize-d, closing its contacts 36b and 36C. The operator then rotates the knob 68 to place the pointer 64b in the position on the scale 58 corresponding to the desired rotational position of the antenna. When the operator releases the knob 68, opening the switch 30, the

asisgsse `7 primarieszot.- the .transformers 261and 28y will 'continueto be.: energized by' virtue off' the'lclosure ofi the holding relay 136;

The..motor182 will thus-rotate in` aldirectiondepending upon :the position .of lthe reversing switch 84.- If "the antenna happensltobe :rotating'inwthe direction- Of'the desired rotational position; its rotation will vbringy theneedle menthe-meter directlyinto line with? the Islits I60rrand 62a-and shut offthe lightlfromf-the lamp v32fto the 4photocelll 34. This ywill increase the resistance-of`the-photo cell Skandi-causeA deenergizationof-'the relayy 36,4V opening its contacts 3612,` 36e and deenergiz'ing'thefprimaries'of theitransformers 26 and 28.l Thi-s .will extinguishE lthelamp 3.2rand fstop' the motor182 with the yantenna-inthe ldesired position.

In lcase thesreversingfswitch *is-1in such" positionthat "the antenna is initially rotated inf thetd-irectionfopposite to that of the-.desiredl rotational position', the. antenna will continue/to-ro-tate.- until-litreachesftherlimit of its rotation in .this direction, at which time-fthe reversing switch 84 will be vactuatedxto reverse the'contacts to 'thel motor 82 and cause rotationof the antenna in the-opposite direction until the desired rotational .position isreached, whereupon thel device will beiturned off.

The modified form of antenna rotator' shown in Figures 3 and '.4 is similarinconstruction and Voperation to that shown inr Figures l yand -2, `except inthe following respects:

(1) lt employsameter. movementf90"h'aving a ksingle needle which is bent-rat-right angles v toprovide `two portions,'90a and 90b, the portion 90a beingr4 arranged to c0- operatewi-tha graduatedscale '92 4to indicatel the position of .the.antenna, andthe portion 90b being arranged to intercept the beam offlight between theincandescent lamp' 32 andthe photocell 34'.

(2) An improved type ofphotoelectric cell 34 is employed having, when illuminated by the lamp 32, resistance low enough to allow'the vseries-connected relay 36to be energized at a voltage not-greater than the conventional domesticservice linevoltage of 115 voltsR. M.Y S. This eliminates the necessity of theauto transformer connection on :the primary winding off the transformer 28 l(Figure l) and makes it possible, asshown'inFigure 3, toconnectthe photocell 34' and relay/'36 directlyacross the terminals ofthe power plug 16. When the lamp32 is not illuminated, the resistancey of the photocell 34 is so high that the amount of current drain is of the order of only a microampere or less, and is `therefore negligible.

(3) A single transformer 94' is employed lin lieu of thc two transformers 26 and 28'in the circuit of Figure l.

The Secdl'y 0f this transformer is tapped toprovide a 2' Winding portion 94a which supplies 29 volts R. M.u S. for the operation'of the motor @Zand a winding portion 94h which supplies 6 volts for the illumination of the lamp 32'. The coil 90b of themeter 90 is connected in series with the potentiometer 556 across the secondary portion 94a of the transformer 94. Thus, the meter 90 indicates only when the transformer 94 is energized-ie. when the motor is actually running, either under manual control or under automatic control. This eliminates the necessity of the

voltage dividing network

46, 48, 50 (Figure 1).

(4) The thermal switch 24 and the receptacle 13 for the television receiver (Figure l) have been eliminated. Since the static current drain of the modified unit is negligible, it becomes unnecessary -to turn the unit off when the television set is not operating.

The motor capacitor 86 has been moved from the motor unit to the control unit 12 where it is connected across the terminals 52a and 52h which are connected through the live-conductor cable 14 with the terminals 54a and 54h of the motor unit and thus across the'motor windings 78and 80.` The electrical circuit of the capacitor and motor therefore remains the same and only 'the physical locationof the capacitor has been changed.

(6) The*physicalarrangementof the meter 90, lamp 32fand photocellf34 in the modified rotator, which is shown in Figure\4,1 is` somewhat different. As may be seen in that ligure, the horizontal portion b of the needle of themeter` 90 is positioned so that its path intersects the :light 'rays between 4the bulb 32 and the photocell 34. Thelamp'z and photocell 34 are mounted on a zmoldedfplastic support 96 which is pivotally supported-1at lits lower end. on an axis coincident with that of 'the meter needle.

The support 96.may.be rotatedby means of a control knob 98 which is mounted at the front panel of the housing.100..'ofthe.control unit cna shaft 102 which also has fixed onitaapulley 104 about which is trained a dial cord 106. This zdi'al cord 106 is also trained about a pair of

idler pulleys

107 and 108 which are rotatably supported at .oppositesidesof the housing .100 and extends inwardly from these pulleys tooppositesides of an eye 110 which is securedxtothe:supportr,96. Rotation ofthe knob 98 thus actuateszzthe dialfcord 106 to rotatethe support 96 to various positions in'accordancewith the desired antenna position.f

ProjectingV forwardlyr from :the support 96is a pointer 112 which extendsthrough an'opening 114a..in atranslucent screen;114-andcooperates with a.` graduated `scale 92 printed on theztranslucent screen to indicate the1rota tional positionxto which the lamp'32 and photocell 34 have been set. Thefvertical portion 90b of the meter needle also cooperates with this scale' 92. to rindicate the actual position oftheantenna.

The faceof'thephotocell 34 directed toward the lamp 32 is paintediexcept forra narrow slit 118i which .is parallel to thel horizontal portion 90b of the1meter'needle and which isnarrower than the needle so.that when the needle is in linewith the unpainted. slit, it will cut oit all ofthe light from the lampg32to Vthe photocell 34'. This eliminates the. necessity-ofl the aperturedhousing shown in Figure 2.

As willfbe understood, the rotator shown in Figures 3 and 4 is simpler and therefore less expensive-in construction thanthe. embodiment of Figures l and2, although the two units function in substantially the same manner.

From the foregoing description, it will be understood that the presentinvention provides a fully practical rotator apparatus capable yof either manual or automatic remotely-controlled rotation to any selected position. It will therefore be understood that vthe aforementioned and other desirable .objectives have been achieved. However, it should be emphasized that the particular embodiments of the invention'whichare shown and described herein are intended as..merely.illustrative and not as restrictive of the invention.

We. claim:

l. vA drivingdevice for a movable member, comprising an electricmotor connected to drive said movable member, a variable. circuit .element mechanically coupled to saidmovable member .and adapted .to vary the amplitude of an electrical current in accordance with the position of said movable member, a meter havinga needle movable in accordance -with theamplitude of said electrical current, aphoto-,sensitive cell and light source positioned adjacent the pathv of vsaidneedle whereby said needle will intercept the light rays traveling from said light source to said cell, said cellandsaid light source being movable i relative to said meter to a position corresponding to a desired positionv of said-movable member, said cell being connected 'to .controlthe supply of electrical current to said motor, whereby said lmotor will drive said movable memberuntil said needle reaches a position corresponding to*said'desired"rotational position of said movable member land intercepts 'saidlight rays:

2'. A-remotelycontrolled driving'device for a1 movablemember; comprising an electric motor connected to'drive said movable'member," ,avariable circuit element mechanically" coupled to said* movable member and asiat-sas adapted to vary the amplitude of an electrical current in accordance with the position of said movable member, a meter having a needle movable in accordance with amplitude of said electrical current, a scale mounted adjacent the path of said needle and being graduated to indicate the various compass directions of said movable member, a photo-sensitive cell and a light source positioned adjacent the path of said needle whereby said needle will intercept the light rays traveling from said source to said cell, said cell and said light source being movable relative to said meter to a position corresponding to a desired position of said movable member, said cell being connected to control the supply of electrical current to said motor, whereby said motor will rotate said movable member until said needle reaches a position corresponding to said desired position of said movable member and intercepts said light rays.

3. A remotely controlled driving device for a movable member, comprising an electric motor connected to drive said movable member, a variable circuit element mechanically coupled to said movable member and adapted to vary the amplitude of an electrical current in accordance with the position of said movable member, a meter having two needles movable in accordance with amplitude of said electrical current, a scale mounted adjacent the path of one of said needles and being graduated to indicate the various compass directions of said movable member, a photo-sensitive cell and a light source positioned adjacent the path of the other of said needles whereby said other needle will intercept the light rays traveling from said source to said cell, said cell and said light source being movable relative to said meter to a position corresponding to a desired position of said movable member, said cell being connected to control the supply of electrical current to said motor, whereby said motor will rotate said movable member until said other needle reaches a position corresponding to said desired position of said movable member and intercepts said light rays.

4. A rotator for a rotatable member, comprising an electric motor geared to rotate said rotatable member, a variable circuit element mechanically coupled to said rotatable member and adapted to vary the amplitude of an electrical current in accordance with the rotational position of said rotatable member, a meter having a needle rotatable to various positions in accordance with amplitude of said electrical current, a scale mounted adjacent the path of said needle and being graduated to indicate the various compass directions of said rotatable member, a photo-sensitive cell and a light source positioned at opposite sides of the path of said needle whereby said needle will intercept the light rays traveling from said source to said cell, Said cell and said light source being secured on a supporting member which is mounted for rotation about an axis approximately coincident with the axis of rotation of said needle, said supporting member carrying a pointer cooperating with said scale for indicating the position of said cell and said light source and facilitating their rotation to a position corresponding to the desired rotational position of said rotatable member, and said cell being connected to control the supply of electrical current to said motor, whereby said motor will rotate Said rotatable member until said needle reaches a position corresponding to said desired rotational position of said rotatable member and intercepts said light rays.

5. A rotator for a rotatable member, comprising an electric motor geared to rotate said rotatable member, a variable circuit element mechanically coupled to said rotatable member and adapted to vary the amplitude of an electrical current in accordance with the rotational position of said rotatable member, a meter having a single needle bent to provide two portions at right angles rotatable about a pivot at the end of said needle to various positions in accordance with amplitude of said electrical current, a scale mounted opposite the path of the portion of said needle adjacent said pivot and being graduated to indicate the various compass directions of said rotatable member, a photo-sensitive cell and a light source positioned at opposite sides of the path of the other portion of said needle whereby said needle will intercept the light rays traveling from said source to said cell, said cell and said light source being secured on a supporting member which is mounted for rotation about an axis approximately coincident with the axis of rotation of said needle, said supporting member carrying a pointer cooperating with said scale for indicating the position of said cell and said light source and facilitating their rotation to a position corresponding to the desired rotational position of said rotatable member, and said cell being connected to control the supply of electrical current to said motor, whereby said motor will rotate said rotatable member until said needle reaches a position corresponding to said desired rotational position of said rotatable member and intercepts said light rays.

6. A rotator for a rotatable member, comprising an electric motor geared to rotate said rotatable member, a variable circuit element mechanically coupled to said rotatable member and adapted to vary the amplitude of an electrical current in accordance with the rotational position of said rotatable member, a meter having two needles rotatable on a common axis in accordance with amplitude of said electrical current, a scale mounted adjacent the path of one of said needles and being graduated to indicate the various compass directions of said rotatable member, a photo-sensitive cell and a light source positioned adjacent the path of the other of said needles whereby said other needle will intercept the light rays traveling from said source to said cell, said cell and said light source being secured on a supporting member which is mounted for rotation about an axis approximately aligned with the axis of rotation of said needles, said supporting member carrying a pointer cooperating with said scale for indicating the position of said cell and said light source and facilitate their rotation to a position corresponding to the desired rotational position of said rotatable member, and said cell being connected to control the supply of electrical current to said motor, whereby said motor will rotate said rotatable member until said needle reaches a position corresponding to said desired rotational position or" said rotatable member and intercepts said light rays.

7. A rotator for a rotatable member, comprising a reversible electric motor geared to rotate said antenna, a variable circuit element mechanically coupled to said rotatable member and adapted to vary the amplitude of an electrical current in accordance with the rotational position of said rotatable member, a meter having a needle movable in accordance with the amplitude of said electrical current, a photo-sensitive cell and light source positioned adjacent the path of said needle whereby said needle will intercept the light rays traveling from said light source to said cell, said cell and said light source being movable relative to said meter to a position corresponding to a desired rotational position of said rotatable member, said cell being connected to control the supply of electrical current to said motor, a reversing switch connected to change the connections to said motor and control the direction of rotation of said rotatable member, said reversing switch being arranged to be actuated when said rotatable member reaches opposite extremes of its full rotational travel of approximately 360, whereby said motor will rotate said rotatable member until said needle reaches a position corresponding to said desired rotational position of said rotatable member and intercepts said light rays.

8. A rotator for a rotatable member, comprising a reversible electric motor geared to rotate said antenna.

aeieess' l11 a7 variable circuit v element mechanically c ')upled tof` said rotatable-member fand adapted to vary -'the. amplitude.` of

.ani electrical current in accordan'ce'with: the rotationalfposition of said rotatable member; a. meterh'aving a;n'eedle movable in accordance lwith the amplituderoftsaid-electrical current, a photo-sensitivecell andlight source positioned adjacentvthefpathiofsaid needles whereby said needle will intercept the light rays travelingzfromsaid light source to saidcell, said celland saidtlightsource being. movable relative to saidrneter to a position corresponding fto a desiredrotational position of said rotatable member, saidcell being connected to'controlthe supply of electrical current to said motor whereby-said motor will rotate said rotatable member until said needle reaches aposition corresponding to said desired rotational. 'position of said rotatable member and intercepts said light rays, and a manually-operable switch arranged so as tto permit electrical current to be supplied to said motor independently of said cell and cause rotation of :said rotatable member in either direction as desired.

9. A rotator as claimed in claim 8 wherein said manually operable switch includes normally closed contacts connected in the circuit of said cell whereby said cell becomes inoperative to supply current to said motor during the time `said manually-operable switch is being manually operated.

10m. A'Irotator vfor `a.rotatable` member, comprising an electric motorfgeared :to rotateV said rotatablemember, atvariable circuitelement mechanically coupled to 'said rotatable memberfand adapted to vary the amplitude of anelectrical currentin accordance with the rotational position-foffsaidrotatable member, ametcr having ,la needle movable in accordance with the amplitude of said electrical current, a photo-sensitive cell and electric .lamp positioned. adjacent the path of said needle whereby said needle will interceptA the lightfrays travelingfrom said electric lamp to said cell, said cell and said lamp being movable relative to said meter to a position corresponding to a desired-rotational position of-said rotatable. member, saidcell being connected intcircuit `withvtheA winding of arelay-Whosc contacts are connected to controlthe supply of current to the winding of said motor land to said lamp, anda normally-open, momentary contact manually-operableiswitch connected across -said relay contacts whereby actuationl of said manually-operable switch `will illuminate said-lamptandstart said motor, andfsaid motor will continue-to rotate said rotatable-:member until said needle reaches-a position cor-responding `tothezdesired rotational position of said rotatable member rand intercepts said light rays.v

11.,.A4 rotator for a-.rotatablememben comprising an electric motor` geared to .rotate isaidwrotatable'member, a variable 'circuit elementmechanically Icoupled'to said rotatablezmember and adapted -to varyY the amplitudeuof any electrical current -in `accordance s with the rotational positionfosaid rotatable` member, .a meter having anneedle movable iny accordance with .the amplitude .of `said electricaltcurrent, a scalemounted-adjacent thelpath of one of said needles and being graduated toindicate the `various compass directions of I said rotatable l member, apltiotoA sensitive cell and `an electriclamp positioned adjacentfthe path of the other of said needles whereby said other-needle willintercept'the light rays traveling from said source! to said.cell,f.said cell and` said-lamp being securedon a supporting member which is mounted forrotation` aboutffan axisvapproximately. aligned with the :axis-'of rotationfof said needles, said. supporting `.member `carryingfa pointer cooperating with said scalefcr indicating the position of said-icell .and said. lamp and facilitate `their rotation to a position corresponding tothe ydesired rotational position of said rotatable member, saidcell being'connected in circuit with the `winding of a relay whose contacts are connected ftoscontrol Athe supplyof current to the winding of-:saidtmotor and `to said lamp, afnorm=allyopen, momentarycontact,l manually-operable switch connected Hacross said relay contacts, a single'` control member` adaptediuto cause rotation 'of .saidsupport 1 and to cause actuationl of said.: switch wherebyI movement of 'saidcontrol member to` set said 'pointer will illuminate saidllamp and startlsaid motor, yand saidmotor will `continue'to rotate said rotatablerrnemberuntil` said needle reaches a" position `corresponding .to the desired rotational position'of fsaidrotat-Y able member and intercepts said lightrays.v

12. A rotator for'a rotatable member, comprising an electric motor geared to rotatesaid rotatable membena variable circuit `element mechanically' coupled'to said rotatable memberiand adapted to vary the amplitudeof an electricalk current in accordance 'with the rotational position of Vsaidrotatable member, a meterhaving a needle movable in `accordance with the amplitude of 'saidelectrical current, a photo-sensitive cell and light source posi-` tioned adjacent the path of said needle whereby said needle will intercept the light rays :travelingfrorn said light source to said cell, said` cell and said light source being movable relative to said meter to'a position corresponding toa desired rotational .position of said rotatable member, said cell being connected tocontrol the supply of electrical current to said motor, whereby said motor will rotate said rotatable member until said needle reaches avposition corresponding to said desiredrotational `position of said rotatable member: and intercepts said light rays, and a manually-operable switch arranged'to connect saidmotorto said source of electrical currentwhereby saidmotor may be controlled either manually orfautomatically.

1?).v A rotator aslclaimed `in `claim l2 inrwhich said manually-operable"switch includes normally closed contacts in the circuit of said photocell to render saidv photocellineiective Vto cause rotation of said motor when said manually-operable switch is actuated.

References Citedin the tile'fof this `patent UNITED STATES PATENTS 1,957,240 Young .May 1, 1934 2,289,242 Chance et al July 7, 1942 2,361,973 Smith Nov. 7.1944 2,377,698 Kettering etal. JuneS, v1945