| 摘要 |
1,232,598. Aircraft arresting devices. DOWTY ROTOL Ltd. 6 Nov., 1968 [13 Nov., 1967], No. 51583/67. Heading B7G. [Also in Division F2] An aircraft arrester hook 11, Fig. 1, fast with an arm 16 and pivoted at 13 to the aircraft is raised and lowered by a telescopic unit 14 which acts both as jack and damper. The unit 14, Fig. 2, comprises a first cylinder 18 connected by an annular step portion 19 to a second cylinder wall 21, in which is movable a piston member 29 carrying a piston 32 which defines within cylinder 18 a chamber 34 into which liquid from a high pressure source 37 may be pumped to contract the unit, a second cylinder 22 concentrically inside the first cylinder 18 and defining therewith an annular chamber 26 and a pneumatic chamber 25 interconnected by ports 24. Annular chamber 25 is sealingly divided from a second annular chamber 45 by a flange 46 and chambers 25 and 26 may have gas pumped into a valve 27 so that a piston 44 floating inside cylinder 22 acts to compress the liquid in a pressure chamber 43 inside the cylinder. A counter-piston 33 forms part of the piston member 29 and has non-return valves 52 associated with its orifices 51 to admit liquid from the pressure chamber to a recoil chamber 54. When the unit is used as a shock-absorber in landing, the piston 32 expels liquid from a chamber 41 through a small orifice 40 in a diaphragm 28 into an annular chamber 45 and from there into pressure chamber 43. An additional flow path from the chamber 41 is provided by a pressure relief valve 42 and a drilled passage 57 in the piston 29. As the counterpiston 33 moves up the cylinder it closes orifices 48 above it and opens orifices 53 below it so that liquid flows in through orifices 53 to a recoil chamber 54 as well as through the non-return valve 51, 52. An apertured flange 30 slides in the first cylinder to provide bearing support for the piston member. If the unit is to be operated as a jack, chamber 34 is connected through a restrictor 35 to an electrically operated control valve 36 energized by a solenoid which connects the chamber 34 to either a high pressure supply line 37 or a return line 38 thus raising or lowering the piston 29. The rate of flow from the pressure line 37 causes piston movement which is not substantially resisted by the orifice 40. The relief valve 42 comprises a plunger 56 mounted in the piston-rod 31 and exposed to fluid pressure in the second chamber 41 by way of a drilled passage 57 in the piston-rod. The other end of the plunger 56 abuts a piston valve 58 of larger diameter which slides in the pistonrod 31 and is loaded by a spring 59. Ports 61, 62 allow fluid flow from the chamber 41 when the fluid pressure on the plunger overcomes the load of spring 59. |
