Patent GB-582471-A (GB)
Title: Hydraulic remote control system
IPC: F15B17/00
Filed: 1944-05-24
Abstract: 582,471. Hydraulic control systems. DEHN, F. B. (Adel Precision Products Corporation). May 24, 1944, No. 10051. [Class 69 (ii)] An hydraulic remote control system comprises a body member or master unit 1 including an hydraulic cylinder 2 in which a piston 3 is displaced by pressure fluid when a control lever 4 actuates a rocking member 28 which controls inlet valves 23, 24 and return valves 33, 34 ; pressure fluid, entering the unit 1 by a port E passes up a central passage 8 and along a passage 9 or 9<1> according to whether the valve 23 or the valve 24 is depressed by the rocker 28. Depression of the valve 2 closes an axial passage 20 in a slidable spool-shaped valve 13 putting its recessed centre portion into communication with the passage 9<1> and the bore 11 housing the valve. The pressure fluid then traverses a passage 17 to the right-hand end of the cylinder displacing the piston 3 to the left until the control lever 4 is held stationary whereupon the piston rocks the member 28 into its neutral position cutting off the pressure fluid. As the piston 3 moves, its opposite end forces fluid from the cylinder 3 through a passage 16 and an axial bore in a valve 12 which is a duplicate of the valve 13, through a passage 21 and a, pipe H leading to a motor unit 53. In this unit, the fluid opens a valve 60 and flows through a passage 62 to one end of a motor cylinder 7. displacing a piston 6 which actuates a control arm 81, of the device to be controlled, through a rack and pinion. Besides opening the valve 60, the fluid displaces to the left a piston 58 which opens a corresponding valve 61 permitting fluid displaced by the opposite end of the piston 6 to escape along a passage 63 to a pipe J leading to a passage 22 in the master unit. The passage 22 communicates through the return valve 34 and passage 41 with a return port F connected to the source of supply. If the control lever 4 is moved in the opposite direction the valve 23 is depressed and the fluid flows in the opposite direction along the passages after traversing the passage 9. After either movement, the return of the rocker 28 to its neutral position allows the valves 12, 13 to close the passages 9, 9<1> and no flow of fluid can occur in the motor system, the piston 6 and control arm 81 being thus locked in position. To synchronise the piston movements, the control lever 4 is moved to either extreme end position, permitting a projection 51 on the cylinder end to unseat a ball valve 50 and open a passageway 49 through the piston. Simultaneously, projections 74 on the motor cylinder open a similar passageway 77 in the motor piston. The pressure fluid can then circulate throughout the system and eliminate air bubbles. If the fluid pressure fails, the control lever 4 actuates the piston 3 but check valves C<1>, C<2> in the pressure fluid inlet and outlet respectively prevent escape of the fluid which returns trom the passage 40<1> to the passage 8 past a lightly held check valve C<3>. A bleed adjacent the check valve C' permits fluid to enter the system to compensate for contraction and spring-pressed plungers 69 opposite the valves 61, 60 allow for expansion.