| 摘要 |
471,705. Door operating appliances. NATIONAL PNEUMATIC CO. Nov. 5, 1936, No. 30148. Convention date, Aug. 5. [Class 65 (i)] A pneumatic engine for operating a sliding door, particularly of a vehicle, is so connected to the door as to be brought into operation by a slight manual opening movement of the door ; the engine may be reversed automatically at the fully-open position of the door and is also reversed automatically if th closing of the door is obstructed. The engine comprises a fixed cylinder 6 with a piston 26 fixed to a piston rod 11 which has secured to it an abutment 13 engaging a bracket 14 fixed to the door ; the bracket 14 is normally held against the abutment 13 by a spring 16 on the piston rod. The door bracket 14 also carries a stop 17 engaging the end of a fluted rod 19 which is slidable in an axial bore in the piston rod and which carries a valve and valveoperating member 31. An airtight disc 28 is secured to the piston 26 by a ring 30, with an interrupted flanged end which limits the motion of the member 31, and to the piston rod 11 by a ring 29, which forms a seating for a valve disc 34 carried by the member 31 ; the member 31 has a cylindrical wall pierced at 31<1> and is formed with extensions 32 passing with clearance through holes in the disc 28 to engage a valve member 35 which is pressed against the disc 28 by a spring 36 to cover the openings through which the parts 32 pass. Compressed air is supplied continuously through a passage 24 to act on the right-hand side of the piston, and in the position shown it is shut off from the left-hand side by valve 35, while the left-hand side is opened to atmosphere through valve 34 and the flutings of the rod 19 so that the piston is moved to the left and the door opens. When the door is fully open, the member 31 strikes a stop 40 (which can be turned out of the way if the door is required to remain open) and is moved to the right, closing valve 34 and opening valve 35, so that compressed air can pass from the right-hand side of the piston through passage 27, valve 35, the passages in disc 28 and openings 31<1> to the left-hand side, where it acts on a greater area of the piston and consequently forces the piston back to the right to close the door, the spring 16 being sufficiently strong to carry the normal closing load. If the closing of the door is obstructed, the spring 16 is compressed and the piston rod 11 slides through the door bracket 14 until the rod 19 strikes the stop 17 on the door bracket and is forced inwards to move the valves to the door-opening position. When the door is fully closed, the valves are similarly set to the opening position shown by slight manual movement of the door relative to the piston rod 11 to operate the rod 19 by means of the stop 17 ; the spring 16 is compressed until the engine takes up the load. |
