Patent GB-535046-A (GB)
Title: Improvements in or relating to locking devices for remote control and other force-transmitting systems
IPC: B64C13/00
Filed: 1940-01-18
Abstract: 535,046. Locking rods. AUTOMOTIVE PRODUCTS CO., Ltd., and CARLTON, Q. H. Jan. 18, 1940, No. 1118. [Class 80 (iii)] [Also in Groups XXIX and XXXIII] Relates to hydraulic locking-devices, especially for aircraft controls, of the kind comprising a piston connected to actuating and actuated members and associated with valves for permitting flow of liquid from one compartment of a cylinder to another, and comprises the provision of valves which are balanced or which tend to open when excessive back-pressures are transmitted by the actuated member, the latter arrangement enabling the actuated member to yield under an excessive load. In the apparatus shown in Fig. 1, a piston 22 is mounted in a cylinder 10 which communicates through pipes 15. 16, 21 with a reservoir 17, the pipes 15, 16 being provided with non-return valves 18, 19. The actuated member is connected to an extension 25 of the piston, and the actuating- member is connected to a rod 31 having a pin 35 which engages a short slot 36 in a pistonextension 28. A slot 38 in the piston communicates through passages 39. 40 with chambers 41, 42 in the cylinder, the inner ends of the passages being provided with valves 43, 44 abutting on pivoted arms 51. 52 which engage springs 47, 48. The rod 31 is provided with a V-head 55 and a pin 57 which engage the arms 51, 52 respectively. When the rod 31 is moved to the left or right, the valve 43 or 44 is relieved from spring-pressure, and when the pin 35 engages either end of the slot 36. the piston and actuated member are positively moved to the left or right, liquid flowing from the chamber 41 or 42 into the reservoir 17. When movement of the rod 31 ceases, the valve 43 or 44 closes, and the actuated member is locked. If, however, an abnormal load is applied to the actuated member, the pressure in the chamber 41 or 42 rises, the spring 47 or 48 is overcome, the valve 43 or 44 opens, and the actuated member yields. In the apparatus shown in Fig. 2, a cylinder 10 containing a piston 22 is mounted in a reservoir 58 which is provided with a filling aperture 61 and communicates through ports 13, 14, 20a with the cylinder. The ports 13, 14 communicate through non-return valves 18, 19 with inclined pipes 69, 70 the arrangement enabling the apparatus to work in inverted position. The piston 22 is provided with extensions 25, 28, the extension 25 being connected to the actuated member, and the extension 28 receiving a rod 31 which is connected to the actuating member. The extensions are protected by boots 74, 76. The piston is formed with a passage 77 which communicates through recesses 78, 79 and passages 80, 81 with chambers 41, 42 on the cylinder. The passage 77 communicates also through passages 82 and the port 20a with the reservoir. The rod 31 is formed with a stem 93 extending through sleeve va.lves 86, 87 which are pressed by springs 94, 95 into engagement with seats at the ends of the passage 77. On movement of the rod 31 to the left or right, a sleeve 98 on the stem 93 opens the valve 86 or 87, the open valve then abuts on the pistonextension 25 or 28, and the actuating-memiber is positively moved to the left or right, liquid flowing from the chamber 41 or 42 into the reservoir. When the movement ceases, the valve 86 or 87 closes and the actuated member is locked. The valves 86, 87 are formed with reduced parts 88 so arranged that pressure in recesses 78, 79 tends to unseat the valves.