Patent GB-517860-A (GB)
Title: Improvements in remote control and indicating systems for radio direction finders
IPC: G01S7/04
Filed: 1938-05-07
Abstract: 517,860. Liquid - pressure remote control systems. CLEVELAND, F. J. (Bendix Aviation Corporation). May 7, 1938, No. 13697. [Class 69 (ii)] [Also in Groups XXXVIII and XL] A radio direction-finder comprising a rotatable directional antenna is controlled from a remote point by hydraulic means and the position of the antenna is indicated at the remote point by a resultant-field electric indicating system. Fig. 1 shows a loop antenna rotatable under manual control by a hydraulic system 3, 6, 5, 5a and adapted to control an electric-indicating system 4, 9 ... 14 the indicator 9 of which is mounted on the radio receiver 8 which is connected to the loop antenna 1 by leads 15 and is provided at 16 with a non-direction antenna. The manual control 6 of the hydraulic system comprises a hand-wheel 7 on a shaft 19, Fig. 2, supported in ball bearings 20 and carrying a pinion 25 which cooperates with slidable racks 26, 27, Fig. 2b, on piston rcds 28, 29. The rods 28, 29 engage pistons 30, 31 provided in hydraulic cylinders 32, 33 which are connected by pipes 5, 5a to a similar cylinder and piston arrangement which through slidable racks and a pinion rotates the antenna. Each pair of cylinders is interconnected by a duct 35 controlled by a valve 36 for the purpose of equalizing the pressure in the tubes 5, 5a and permitting adjustments of the positions of the pistons. The rotation of the hand-wheel 7 is limited by the cooperation of pins on the hub 7a and a freely mounted ring 38 on the shaft and fixed pins on the casing plate 24. The handwheel also may be locked in position by handoperated jaws 46, 48 which grip a flange 44 on the hub. The antenna is mounted on a shaft supported in ball races and carrying in addition to the actuating pinion, slip-rings for making electrical connection to the antenna and a coupling disc having a pin which engages a hole on a similar disc on the shaft of the electric transmitter. The transmitter and receiver comprise polyphase stator windings and single-phase rotors supplied from an A.C. source. The rotor of the receiver operates a pointer over a graduated dial and an annular ring carrying a transparent cover is adjustable relatively to the scale. The cover bears a semi-circular mark which is adapted to cover a portion of the scale in order to facilitate the taking of bearings when the antenna is used in conjunction with the non- directional aerial 16. Fig. 8 shows arrangements for maintaining the oil pressure in the hydraulic system and for furnishing additional oil to the system to compensate for leakage. A pressure reservoir 95 adjusted for pressure between 25 and 50 pounds per square inch is connected to the tubes 5, 5a through high-pressure relief valves 96, 97 and automatic refill valves 92, 93, the former operating if the pressure in the pipes 5, 5a becomes too high and the latter when additional fluid is required owing to loss of pressure. The reservoir 95 is supplied from a main reservoir 102 by a pump 103, a bye-pass valve 99 being provided to return fluid to the reservoir 102 when pressures exceeding the maximum pressure of the reservoir 95 are reached. The pump 103 may be operated by one of the pistons of the hydraulic control or independently. The pistons of the control systems are free to move independently of the piston rods and therefore are always in contact with the fluid medium under the effect of the piston rods or under atmospheric pressure if the pressure is incorrect or leakage has taken place. This arrangement facilitates a ready determination as to whether the system is operating correctly since loss of pressure creates an apparent backlash in the operation of the manual control.