GB753129A - Improvements in or relating to power door operating systems - Google Patents

Abstract

753,129. Door-operating apparatus. NATIONAL PNEUMATIC CO., Inc. March 25, 1954 [Dec. 1, 1953], No. 8733/54. Class 65 (1). An hydraulic door engine for vehicle doors, supplied with fluid under pressure from a motordriven pump through a control valve for opening and closing, is also connected to an accumulator when the valve is in the door-closing position so that any manual opening of a door forces fluid into the accumulator and as soon as the door is released it is re-closed by the pressure in the accumulator. In the arrangement shown, the pump 22 draws fluid from a reservoir 24 (to which it has a relief by-pass 60) and delivers it to an accumulator 16 (with which is associated a pressure-sensitive pump-controlling switch 18) and a valve 10 which may be operated electrically, pneumatically, hydraulically, or by hand. The valve 10 in one position connects the accumulator and pump to the left-hand end of the door-engine 8 and the other end of the engine to the reservoir through pipe 52, to open the door, and in the other position reverses the connections to close it; the passage 44 is restricted, to reduce the closing speed by throttling the exhaust, but is by-passed to allow free opening by a one-way valve 66. The door can be opened manually against the pressure applied by the accumulator, and this pressure will re-close the door as soon as it is released. If the passage 44 is large enough to allow free opening the passage with the valve 66 may be omitted. In a modification, Fig. 3 (not shown), a differential engine is used, and the accumulator is incorporated in it at the small (door-closing) end, the valve 10 controlling the other end only. The passage 44 is made of full size, and the closing of the door is checked by a restriction placed on the supply side of the valve 10. A power unit comprising all the hydraulic system in a compact assembly is described (Fig. 1, not shown), the engine actuating a rack engaging a toothed-sector on a shaft carrying a door-operating arm; the end of the sector meets a stop when the doors are open.