US 3197683 A
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July 27, 1965 R P BENNETT ETAL I PULSE OPERATED REMOTE CONTROL SYSTEM Filed Dec. 27. 1961 INVENTOR ROBERT E BENNEH WILLIAM G LICHT'NERTE. BY 3M um ATI'ORNEY United States Patent 3,197,683 PULSE OPERATED REMUTE CONTRQL SYSTEM Robert P. Bennett and William 0. Lichtner, Jr., Raleigh,
N.., assignors to Cornell-'Dubilier Electric Corporation, a corporation of Delaware Filed Dec. 27, 1961, Ser. No. 162,501 2 Claims. (Cl. 318-16) This invention relates to remote control systems and more particularly to a remote control for an electrical device such as an antenna rotator.
The use of antenna rotators has become widespread in connection with the reception of television signals in fringe areas. Whereas in strong signal areas adequate signal strength may be achieved by positioning an omnidirectional antenna in one direction, the antennas for fringe areas are necessarily highly directional to achieve good reception. Where multiple signal sources are encountered in fringe reception the use of plural directive antennas or of an apparatus for selectively directing a single antenna toward a desired signal source is indicated. Such directing devices are known as antenna rotators.
Antenna rotator systems normally comprise a control device or actuator positioned at the receiver and a remote, selectively energizable, motor for rotating and positioning the antenna. Normally, the antenna rotating motor is mounted at the top of the antenna mast or tower and directly supports the antenna itself. The rotator proper is connected to the control device at the receiver by a plural conductor cable.
The actuator or remote control device per se normally comprises a manually operated switch for controlling the drive motor and in some types a visual indicator for depicting at the receiver the position of the remote antenna. Recent advances in the television receiver art have resulted in the introduction of remotely controlled television sets. In sets of this type the viewer may change channels, adjust the sound volume and turn on and turn oli the set from across the room. It is an object of this invention to provide a fully remotely controlled system for supervising the operation of an antenna positioning rotator. It is another object of this invention to provide an improved remote control antenna rotator system.
A common type of antenna rotator utilizes a drive mechanism and motor that is capable of rotating the antenna through only one revolution. When the motor drives the antenna to its limit in one direction, the motor would be blocked and would be subject to damage. To avoid this, limit switches might, conceivably be installed with the rotator; but such a provision would require additional control wiring from the control point at the receiver to the antenna rotator. Accordingly, a further object of the invention resides in provision of novel apparatus for efifecting limit-stop control of the antenna rotator without the complications involved in limit-stop switches.
The above and other objects of the invention are achieved by an illustrative embodiment of the invention which is described in detail below.
In one aspect of the invention there is provided a remote control system to enable the person using the equipment to operate the control apparatus for the antenna ice the antenna drive motor, in repeated sequence. The person operating the equipment has a pulse signal source that he uses to control the stepping switch. For starting the drive, a first pulse is transmitted. After the rotation has progressed suificiently, the next pulse advances the stepping relay to the neXt part of its program and the drive is interrupted. If the antenna is rotating in one direction and it is desired to cause it to reverse, then two pulses are transmitted so as to stop antenna rotation and then initiate reverse-drive of the antenna rotator.
Because of numerous practical considerations, antenna rotators are commonly limited to operate the antenna through no more than one complete revolution. After the limit is reached in one direction of rotation, if it is desired to operate the antenna to a position beyond that limit-stop position, the antenna is rotated reversely.
The apparatus disclosed in detail below provides automatic communication of information to its control apparatus when the antenna is presumed to have reached a limit in either direction of rotation, after a suitable period of motor energization, without resort to limit switches at the antenna rotator and associated wiring for transmitting this information. In all three embodiments of the invention described in detail below, the operating parameters of the antenna rotator are taken into account and related to the operating parameters of a deferred-action auxiliary switch. This auxiliary switch provides an automatic program advancing pulse if the person using the equipment should fail to do so after the antenna rotator is blocked by its stop. The pulse advances the program relay one step so as to interrupt the rotation and place the apparatus in condition for reverse rotation. If the user desires further search for optimum positioning of the antenna, he need only restart rotation of the antenna by a pulse. There is thus provided a system of automatic communication of information relating the antenna rotator to its control apparatus. The system also efiFects automatic advance of the switching program.
Several embodiments of the invention are described in detail below. From this description the nature of the invention in its various aspects and further objects and features of novelty will be more fully apparent. Reference is made below to the accompanying drawings forming part of this disclosure. In which drawings:
FIG. 1 is a system wiring diagram;
FIG. 2 is a wiring diagram of a modification of a portion of the circuit in FIG. 1; and,
FIG. 3 is a wiring diagram of another modification of a portion of the circuit in FIG. 1.
The illustrative circuit shown in FIG. 1 provides a pulse signal source 10 which produces, in this situation, a pulse of super-audible sound as by striking a tuning fork. The pulse is picked up by the transducer 12 of the control unit 14. The output of the transducer 12 is the input of an amplifier 16 of a conventional type. The amplifier supplies an amplified pulse to the coil 17 of the first switching device or relay 13. The pulse causes the contacts 20 of the relay 18 to closethereby connecting the coil 21 of a program relay or stepping switch 22 to the source of AC. power 24. Program relay 22 has a ratchet-and-pawl mechanism 22a for rotating its cams 22b stepwise and operating its output contacts 26, 23, 3th which are sequentially connectable to the source of power 24 according to the programing sequence shown in Table 1 below:
Table 1.-Cntact program relay 22 Contact Configuration Contact N0. 1
Once the contacts have been closed in a particular configuration they remain in that configuration until the relay is pulsed again. Contacts 26, 28, and 30 are utilized to control the direction of rotation of the rotor unit 32 which is connected to the remote control unit 14 by multiconductor cable shown schematically at 34.
Contact 26, when closed, energizes transformer as by connecting the transformer to the power supply 24. Contacts 28 and 30 are both connected to the secondary side of the low voltage transformer 36 and are closed alternately to energize the counter-clockwise or clockwise windings 38 and 40 of motor 41 through cable 34 in accordance with the program shown in Table 1. Transformer 36 or cable 34- may be considered as components of the energizing means for the antenna rotator. Rotor unit 32 supports and rotates the antenna 4-2 as shown diagrammatically in H6. 1. As pointed out above the rotor unit is energized by the low voltage transformer 35 so that the cable 34 carries lower than line voltage, as for example 24 volts A.C. In order to get the proper force output from the built-in motor, which is of limited size and weight in view of its mounting place, a gear reduction system is required between the motor 41 and the rotor output to which the antenna 42 is connected.
The signals received by the antenna are carried by a transmission line, not shown, to the receiver. In order to limit the rotation of the antenna so that the transmission line is not wrapped about the supporting mast the antenna rotator units are generally provided with mechanical stops which limit the rotation of the antenna to approximately 360 in either direction. Whereas in prior units the user was fully in control of the rotator because of the required manual actuation of the direction or control switch at the actuator, no problem was encountered when one of the stops was reached since this would become immediately known to the operator by his observation of the visual indicator on the control apparatus. In the present situation the operator is at a distance from the unit and may therefore attempt to continue the rotation of the antenna beyond the limit stop without realizing that the rotation had stopped. However, the deferredaction auxiliary pulsing means 44 is activated by the closing of contacts 26 which also energizes the transformer 36. Pulsing means 44 includes a resistance element 45 which is connected in parallel with one of the windings of transformer 36 being shown in FIG. 1 in parallel with the primary winding of the transformer 36. Bimetal 46 is responsive to the heating of element 45 and is disposed in close proximity to but insulated from the bimetal. When the bimetal i6 is heated it is deflected and contacts 48 close. Contacts 48 actuate the program relay 22 causing the contacts 26, 28, 3th to shift to the next configuration which is always an off position as shown in Table 1. The time vs. temperature characteristic of the sensing means or auxiliary means 44 for a particular input level, is coordinated with the operating parameters of the rotor such as r.p.m. and current, so that the contacts are not operated during the time required for one complete revolution of the antenna under normal conditions. When the rotor reaches a stop within this period it will remain energized until the period expires but this is for so short a time that no harm can occur to it. When the bimetal as cools the contacts 43 part thereby automatically resetting the control unit for its next operation. The next pulse, which activates the rotor control unit, results in rotation in the reverse direction away from the previously encountered rotor unit stop.
The remote control antenna rotator system functions in the following manner. When the actuator it? is operated by the viewer a super-audible sound wave pulse is produced which is picked up by the transducer 12. The output of the transducer is fed into the amplifier 16. The output of the amplifier energizes coil 17 thereby actuating the first switch 18. When the relay 1% is actuated the contacts 2% are closed in turn energizing the coil 21 of the program relay 22. Assuming the cycle of operation is commenced with all the contacts of relay 22 open (Configuration No. 1 of Table 1) then the first pulse operates the relay is and then relay 22;. The contact connections of the relay 2?. would then shift to the position indicated as No. 2 in Table l. The rotor unit 32 is energized and will begin to drive the antenna counter-clockwise as the counter-clockwise winding 38 is connected by Contact 23 to the power source 24 through the transformer as. The rotation will continue until either a rotor unit stop (not shown) is reached or until the program relay 22 is pulsed again changing the contact Configuration to No. 3 shown in Table l. In Configuration No. 3 the rotor is stopped since neither winding is energized. The next pulse operates the program relay 22 to Configuration No. 4 and results in the clockwise rotation of the antenna until the relay Z2 is pulsed once again to position No. 5 which is identical to No. 1.
In another embodiment of the invention advantage is taken of the fact that, when the antenna drive motor d1 reaches the limit of its rotation in either direction, there is an increase in its current drain. In this modification (FIG. 2) bimetal as of the deferred-action pulsing means 44 is responsive to the heating of a resistance element 45 disposed in close proximity to but insulated from the bimetal. This resistance element and bimetal are located any convenient position, either on the transformer or spaced from it. Resistance 45 is here connected in series with one of the windings of transformer 3 6', being shown in FIG. 2 in series with the contact 26 and the primary winding of the transformer.
In operation,'the normal operating current of the transformer as causes only moderate heating of resistance element 4-5. When the antenna rotating motor 41 is blocked, as a result of reaching a stop, then the current through resistance element 4-5 increases. The resulting increase in heating produced by this resistor increases the deflection of bimetal 46. After a time delay the deflection of bimetal 46' becomes suflicient to close contact 48 to produce a pulse which advances the program relay 22 one step. The rest of the system operation is the same as described in connection with FIG. 1.
In yet another embodiment of the invention (FIG. 3) the resistance element 45 is omitted and advantage is taken of the fact that there is an increase in temperature of the core of transformer 36 in response to the increase above normal operating current which occurs when the movement of the rotor is blocked as by a stop. The current drawn by the motor 41 is relatively constant for the normal operation of the rotor unit 32. However, when the rotor is blocked the current rises above the normal value. This increase in current drain is used to communicate the fact that the rotor has reached a stop to the control apparatus. The sensing means 44" is located adjacent the core of the transformer 36 and when current level through the transformer winding rises, the temperature of the core rises. The sensing means 44" has a bimetal 46" which is deflected in response to the heating of the core. Th mass of the core gives an inherent time delay thereby avoiding interruptions due to current surge when starting rotation in normal service, or when the load on the rotor unit is increased as by wind or ice. When the bimetal 46 is deflected contacts 53" close and the program relay 22. is actuated causing the contacts 26, 28, 30 to shift to the next configuration. When the transformer has cooled the contacts 48 part thereby automatically resetting the control unit for its next operation.
The first relay l8 and the program relay 22 may be replaced by equivalent solid state and other switching devices within the broad contemplation of the present invention. Further, a visual indicator responsive to the position of the antenna and a manual control may be added to the aforedescribed system. It will be apparent to those skilled in the art that these and other changes and modifications may be made without departing from the spirit or scope of the invention.
What we claim is:
1. Control apparatus for operating a remote antenna comprising a reversible motor for rotating said antenna, a pair of mechanical stops that limit the rotation of said antenna to substantially 360, control apparatus remote from said motor for energizing and controlling the duration of rotation of said motor, said control apparatus including energizing means for said motor, remote-control pulsing means, program switching means responsive to said pulsing means and arranged to advance a step at a time in response to each pulse, said program switching means having plural successive closed and open control positions in which said motor is energized and tie-energized, respectively, alternative ones of said closed control positions energizing said motor for rotation in opposite directions, and deferred-action auxiliary pulsing means arranged to provide an advancing pulse to said program switching means to advance said program switching means from a closed control position to an open control position, the operating parameters of said auxiliary pulsing means and said motor being coordinated so that said auxiliary pulsing means will operate after said antenna should have reached a stop having started from its most distant position, said program switching means having switching connections eifective concurrently to energize said motor energizing means and said auxiliary pulsing means and, thereafter, effective concurrently to de-energize said energizing means and said auxiliary pulsing means.
2. Control apparatus for operating a remote antenna comprising a drive motor having plural windings for clockwise and counterclockwise rotation of said motor, stop means for limiting the rotation of said antenna to substantially 360, control apparatus remote from said motor for energizing said motor and for controlling the direction and duration of rotation of said motor, said control apparatus including energizing means for said motor, a remote-control pulse signal source, a receiver for said pulse signals, an amplifier at said receiver for said signals, a first switching means operable by said amplifier in response to plural signals from said source, step-by-step switching means operable by said first switching means for controlling the sequential energization and de-energization of selected ones of the windings of said motor for producing sequential periods of rotation of said motor in opposite directions with interposed de-energized positions, and deferred-action auxiliary switching means arranged to advance said step-by-step switching means from a motor energizing step to a motor de-energized step, the operating parameters of said auxiliary switch ing means and said motor being coordinated that said auxiliary switching means will operate after said antenna should have reached a stop having started from its most distant position, said step-by-step switching means having switching connections effective concurrently to energize said moter energizing means and said auxiliary switching means and, thereafter, effective concurrently to de-energize said energizing means and said auxiliary switching means.
References Cited by the Examiner UNITED STATES PATENTS 2,55 8,032 6/51 Andrew 318472 2,611,883 9/52 Richards 318-469 2,715,706 9/52 Chin 318-469 2,992,378 7/61 Schneider 318469 3,075,400 1/63 Carlson 3 l846l JOHN F. COUCH, Primary Examiner.