GB752812A - Improvements in or relating to buffer devices for pressure-fluid actuated pistons - Google Patents

Abstract

752,812. Pneumatic single stroke apparatus. NATIONAL PNEUMATIC CO., Inc. Feb. 19, 1954 [Oct. 28, 1953], No. 4931/54. Class 8(2). A pneumatic motor including pistons 4a, 4b in a cylinder 2 operating a lever 16 through a rack 8 and pinion 12 comprises end members 20 each having a chamber 38 in which is slidably mounted an auxiliary piston 40 having an extension 401 which is contacted by the piston 4a or 4b at the end of its stroke. The chamber 38 communicates with a chamber 50 through a passage 46 and a passage 48 having an adjustable restriction screw 52. The chamber 50 communicates with the chamber 38 on the opposite side of the piston 40 through a passage 54. The chamber 50 is connected to a source of high pressure; as shown, the chambers 38, 50 contain hydraulic fluid and the chamber 50 has a connection 60 to a pipe 78 connected to a source 62 of pneumatic pressure which is also connected to a valve 64 which controls the application of pressure to the cylinder 2 through connections 36 and restricted passages 26 in the end members 20. Exhaust from the cylinder passes through a duct 24 controlled by a ball valve 32. The chamber 50 may be subjected to a separate source of pneumatic or hydraulic pressure. A baffle may be provided to screen the connection 60 from the hydraulic fluid or the pipe 78 may include a non-return valve.