Patent GB-552712-A (GB)
Title: Improvements in or relating to hydraulic remote control apparatus
IPC: F15B7/10
Filed: 1941-09-17
Abstract: 552,712. Hydraulic remote controls. RUBERY OWEN MESSIER, Ltd., HADEKEL, R., and ARNOT, A. Sept. 17, 1941, Nos. 11940 and 15473. [Class 69 (ii)] In a hydraulic telemotor control apparatus in which transmitting and receiving cylinders 11, 12, Fig. 1, containing pistons 15, 19 are connected by pipe lines 13, 14, thermal expansion of the liquid is provided for by connecting each pipe 13, 14 to an expansion chamber 23, 24 containing a movable expansion member such as pistons 25, 26 which can yield together under pressure due to thermal expansion, but are restrained from movement under working-pressure applied differentially to the pipes. The pistons 25, 26 are integral and are depressed by a spring 27, and the liquid from the pipes 21, 22 act upon equal areas, so that pressure set up by movement of the lever 17, which operates the piston 15 by a cam preferably of involute shape, does not move the pistons since the increase in pressure on the piston 26 is balanced by a decrease in pressure on the piston 25 or vice versa. The cylinder 11 is fitted with a filling-aperture closed by a screw plug and the two ends of the cylinder are connected by a passage closable by a screw valve which is opened when the transmission and receiving pistons are to be synchronized. The receiving-cylinder is fitted at each end with bleeder screw plugs which when unscrewed permit flow of liquid to atmosphere. A modified form of receiver, Fig. 4, is constructed to permit of synchronization by the action of adjustable tappets 33 carried by the piston rod 20 on normally spring-closed valves 34, 35 which when opened permit passage of liquid from one side of the cylinder 12 to the other via passages 37, 38, 39. The arm 30 of the tappet moves over guides 47 and is fitted in a cage 48. The spring 25 may transmit pressure through a cam, and may be arranged so as to surround the chamber in which the pistons 25, 26 are arranged. In place of a piston as 25, 26, two pistons of equal size may be used. Pneumatic pressure may replace spring pressure. In a modification suitable for transmitting high loads the pipes 13, 14 are connected to the cylinders 23, 24 via pipes 78, 77, Fig. 7, and valves 70, 71 the stems of which normally abut to keep the valves open against the action of springs 73, 74. If a high pressure is produced in say pipe 14 it closes valve 70 and cuts off the high pressure from the temperature-compensating device. At normal pressures this device acts as in Fig. 1, and in a modification of this form the valves are arranged in separate cylinders fitted with pistons which are operated to cut off the pressure from the temperature-compensating device by the high pressure. The valves are normally kept open by springs. In a modification, Fig. 9, an accumulator 91 replaces the cylinders 23, 24 and temperature increases in the lines 13, 14 cause the expanded fluid to pass through valves 95, 96 into a chamber 94 connected to the accumulator, the valves 95, 96 being opened by expansion of liquid below pistons 105, 106 which act upon a lever 104 connected to a valve rod 101 normally depressed by a spring. Increase of pressure in one only of the lines 13, 14 causes pivotal movement of lever 104 without operation of the valves. In a further modification the pipes 13, 14 are connected to separate cylinders with pistons acted upon by light springs. The pistons carry racks with inclined teeth which mesh with skewed tooth gear wheels on the same shaft with capacity of driving the gear wheels but not to be driven by the wheels. Movement of the pistons can thus take place only when each is subjected to increase or decrease of pressure due to temperature changes. Specifications 118,338, [Class 69 (ii)], 479,236, 509,350 and 548,295 are referred to.