Patent GB-577177-A (GB)
Title: Improvements in electric remote control systems
IPC: F41G7/30
Filed: 1941-08-13
Abstract: 577,177. Electric control systems. THOMSON, B. Aug. 13, 1941, Nos. 10298 and 16548. [Class 40 (i)] [Also in Groups XXXVII and XL] An electric remote control system particularly for torpedoes, crewless vehicles or water craft comprises a transmitter for producing a cyclically a sequence of signals and countersignals for exerting or indicating controls in opposite directions, and a receiver which distributes the signals and countersignals to the appropriate controls, the movement in response being dependent on the difference in duration of the signals and countersignals. The invention is described as applied to elevator and rudder controls of an aerial torpedo-glider stabilized laterally by a gyroscope. The torpedo may be arranged as described in Specification 577,002. Sets of signals and countersignals are sent for each control and on reception and distribution may operate directly on reversible electric motors or indirectly by means of follow-up mechanisms. Transmitter, Figs. 1 and 2. The transmitting switch comprises a rotating drum 1 driven at constant speed and shaped as shown so that two conducting strips 8 and 9 engage, in turn, brushes 20, 21 carried by arms 22, 23 the angular positions of which may be varied to transmit rudder and elevator control signals and countersignals. Battery connection to the strips 8, 9 is made by a brush 14 and slip ring 3 which is formed with a projection 7 which makes contact once per revolution with brush 19 to transmit synchronizing signals. The strips 8, 9 are tapered in width in opposite directions so that when the brushes 20, 21 are central, the durations of contact with the strips are equal but the duration of contact with strip 8 increases and with strip 9 decreases, or vice-versa, as the brushes are moved from the central position. One strip 8 provides signals producing movement in one direction and the other strip 9 the other direction. A modified transmitter is described later. One cycle starting from the synchronizing signal comprises rudder signal, elevator countersignal, rudder countersignal, elevator signal. Transmission may be by line or wireless, but preferably short wave wireless synchronizing signals are sent alone until switch 29 is closed. The cranks 26, 27 which control the position of the brushes may be connected to a single universally mounted operating lever. Receiving and controlling arrangements. Fig. 4 shows arrangements for short wave reception comprising a pair of di-pole aerials 41 screened by reflectors 42, the receiving set 40 being switched on by a time switch 43 some 10 to 15 seconds after the torpedo has been released. The signal pulses, after detection, control contacts 57, 58 of relay 45 which repeats them over distributer 68 to the synchronizing drive 80 and to the follow-up control devices 78R, 78E of the rudder and elevator motors 121R, 121E which are reversible. Constructions of relay 45, distributer 68, synchronizer 80 and follow-up devices will be described later. The distributer rotates at half the speed of the transmitter switch and has two sets of contact segments. The signals and countersignals for the rudder control pass from distributer contacts RS, RC to coils 100R, 101R on an axially rotatable ring 99R mounted in the field of magnet 122R so that signals and countersignals of equal duration are ineffective apart from causing slight oscillation, but when the duration of the signals or countersignals predominates, the ring rotates in one direction or the other to bring brush 113R on to arcuate contacts 114R, 115R carried by a follow-up member 137R. As a result, magnet 161R or 162R is operated to close a switch 170R or 171R for driving the motor 121R in the appropriate direction until the follow-up member 137R driven by gearing 131R from the motor restores the contacts 114R, 115R to the position where brush 113R is out of contact. The switch connections for the motor include the cores of the operating magnets. The elevator control is similar. Signal repeating relay 45, Figs. 5 and 6. Two field coils 47, 48 are mounted on a flanged brass sleeve 50 one on each side of a light alloy core 49 in two halves connected by screws 52. The signal receiving windings are carried on an armature 44 rigidly attached to a light alloy torsion spindle 53 pivoted at one end in a pin 54 adjustably secured on the core 49 and at the other end rigidly fixed to the core at 56. The armature carries a contact member 57 normally engaging a stop 59 and separated by a gap of 6/1000in. from contact 58 with which engagement is made on receipt of a signal. The stop and fixed contact are mounted on and insulated from a flange on the brass sleeve. Distributer and synchronizing drive, Fig. 8. The distributer contacts 72 are carried by a member 68 fixed in a housing 68a and the holder 74 carrying the brush 75 is rotated by a hexagonal extension 73a on shaft 73 which carries a brass flywheel 80 having two iron segments 81 and a slot 98 which is engaged by pivoted catch 97 forming part of the magnetic circuit of electromagnet 93. The shaft 73 has a pinion 82 normally engaging a rack 83 on the piston of a dash pot 89, the piston being in its lowermost position with spring 90 compressed. In this condition, the catch 97 engages the slot in the flywheel and the distributer brush engages a synchronizing contact (S.S. Fig. 4), the position being indicated by a pointer 75a. On receipt of the first effective synchronizing signal magnet 93 is energized, catch 97 released, and shaft 73 is rotated about half a revolution by the spring 90 and rack-gear before the next synchronising signal comes in. The rack has now run off the pinion and the next signal applies torque to the distributer shaft by means of magnet 93 and the approaching iron segment 81, the arrangement then continuing to run as a synchronous motor. Follow-up control, Figs. 10 and 12. The signal and countersignal receiving coils 100, 101 are wound on a magnetic ring 99 and cause rotation of the ring in one or the other direction in the field of a D.C. energized electromagnet 125 having pole pieces 125. The ring is fixed to an arm 102 which is pivoted in bearings 104, 105 in a casing and carries a brush 113 adapted to make contact with one or other of the arcuate contacts (114, 115, Fig. 4) mounted on a member 116 secured to a sleeve 108 rotatable relatively to the casing. When the brush makes contact and energizes motor 121 mounted on the lower end of the casing, the motor drives the rudder (or elevator) control shaft 138 by means of screw gearing 139 and also rotates sleeve 108, through gears 130, 131, 136 and arcuate rack 137, until the contacts are disengaged from the brush. In a modification, Figs. 14-17 (not shown), the controller is rectilinearly movable and comprises an energized pot magnet with a sliding armature which carries sets of signal coils and countersignal coils and a brush associated with the follow-up contacts which are driven from the motor by screw gearings. The weight of sliding armature is balanced by a counterweighted lever. A further modification. Figs. 18 to 20 (not shown) comprises a rotary controller in which the follow-up contacts are driven directly from the rudder or elevator control mechanism instead of by gearing from the motor. Modified transmitter, Figs. 21 and 22, giving initial boost to compensate lag in operation of the receiver. The rudder or elevator control brushes, e.g., rudder brush 291 are connected to the primary control lever by an electromagneticescapement-controlled multiplying lever system comprising levers 290, 299, 305 freely mounted on shaft 293, lever 290 being connected to the control lever and 305 to the brush lever. The rotating contact drum 292 carries a commutator extension 314 co-operating with brush 313 to operate electromagnet 310 intermittently. When lever 290 is moved by the control lever, movement of brush 313 and energization of magnet 310 holds shaft 293 and crank arm 295 with crank pin 296, movement of the lever 290 taking place against the action of one or other of springs 297 engaged by the crank pin. The pin 301 on lever 290 therefore rotates a multiplying lever 299 which carries with it the lever 305 connected to the lever 307 operating brush 291 over an abnormally large angle. When the electromagnet 310 is de-energized the spring 297 tends to restore the levers 299, 305 to their normal position relative to lever 290 but this may require a few periods of de-energization during which the ratio of signal to countersignal is larger than would normally correspond to the displacement of the control lever. The shape of the conducting segments 317, 318 is also modified to provide for large displacements of the brush, constant abnormally long signals and abnormally short countersignals.