Patent GB-875410-A (GB)
Title: System for starting an engine and operating an associated hydraulically driven device
IPC: B64C27/04
Filed: 1959-05-05
Abstract: 875,410. Hydraulic transmission of power. UNITED AIRCRAFT CORPORATION. May 5, 1959 [Sept. 2, 1958], No. 15334/59. Class 69 (2). [Also in Group XXVII] A system for starting an engine 6 and operating an auxiliary device 93 comprises a first conduit 72 and first valve 70 connecting an accumulator 76 to an hydraulic motor 32, and a source of fluid pressure 64 which is connected by a second conduit 68 and check valve 148 to the accumulator, by a third conduit 91 and a blocking valve 90 to the device 93, and by a fourth conduit 100 to a pressure-relief valve 102, the blocking valve opening when the pressure relief valve opens and closing when the first valve opens. The system may be used for starting the two engines 4, 6 of a helicopter having an auxiliary device such as a cargo hoist, landing gear or taxi gear. The engines are started by motors 30, 32 which are connected to the engines by over-running clutches 34, 36 arranged to be disengaged at a predetermined speed. The motors are selectively connected by a manually-operated valve 46 to the line 72 from the accumulator which is charged by fluid pressure from the source 64 consisting of a pump driven by a motor 65, check valves 74, 148 preventing reversal of flow in the conduit 68 to the accumulator. The blocking valve 90 and pressure-relief 102 are combined in a unit consisting of a housing 200 having cylinders 202, 204 in which are pistons 206, 208 interconnected by a rod 210 and urged to the left by a spring 214. A rod 216 extends from the piston 208 and carries a member 218 which co-operates with one end of a latch 280 rotatable about a pin 286, the opposite end of the latch having a pin 288 engaging a slot in the rod 241 of a solenoid controlling the valve 70. When a switch 86 is actuated to energize the solenoid controlling the valve 70 and connect the accumulator 76 to the selected motor to start one of the engines, the rod 241 is raised to pivot the latch and permit the spring 214 to move the pistons 206, 208 to the left and block the flow of fluid from conduit 92 to conduits 96, 91 leading to the auxiliary device, a pressure switch 118 in the line 91 turning an indicator light 126 out. After the engines have been started, the switch 86 is opened to close valve 70 and disconnect the accumulator from the motors 30 and 32. Closing of a switch 116 operates the motor 65 to drive the pump 64 which charges the accumulator, the pressure in lines 92 and 100 urging the pistons 206, 208 to the right. When the accumulator is charged to a predetermined pressure, the member 218 engages the latch and moves to a position A wherein a port 240 is uncovered to permit the pressure in conduit 100 to move pistons 226, 228 to the right against a spring 236 so that fluid pressure is released and fluid passes through conduits 104, 98 to a reservoir 60 and filter 61. With the release of pressure through conduit 104, the member 118 moves back to position A to close port 240 and permit the pressure to be supplied through a port 238 uncovered by the movement of pistons 226, 228 to the conduits 96, 91 when it is regulated by a valve 94 before passing to the auxiliary device 93; the pressure in the accumulator is maintained by the valve 148. A manuallyoperated pump 128 or an external source connected to couplings 130, 136 may replace the pump 64. The auxiliary device may be operated by the pressure in the accumulator under the control of an on-off valve and a pressure regulator 146 in a conduit 142.