| 摘要 |
879,445. Door operating appliances. WESTINGHOUSE BREMSEN-G.m.b.H. Oct. 9, 1959 [Oct. 11, 1958] No. 34271/59. Class 65(1). An electro-pneumatically controlled door-operating apparatus comprises a main pneumatically actuated door-operating piston the door closing movement of which is impeded and cushioned by a trapped volume of compressed fluid and is completed only after the release of the trapped fluid, the trapped fluid being connected to a supply reservoir and bounded by an auxiliary piston which is mounted in the path of travel of the main piston and the end position of which is determined by a stop. The apparatus of Fig. 1 is shown in the "door open" position, the auxiliary piston 28 being mounted on the piston rod 18 of the main piston 17 and held in the end position, which is determined by stop 28a, by the pressure of the trapped fluid in the cylinder space 30 and by a spring 29. During the opening operation compressed fluid, e.g. air, is supplied through a pipe 6, and passes to the space 30 through an annular by-pass pipe 32, magnetically releasable non-return valve 12 (Fig. 3, not shown), and port 33, and to the space 35 between the pistons 17, 28 through a chamber 34 and passage 36 between the piston 28 and the piston rod 18. Fluid in the chamber 20 in front of the piston 17 is evacuated through a pipe 5, the final stage of the opening movement being damped by the means 22, 23. When the door is to be closed compressed fluid is supplied through the pipe 5 and moves the piston 17 until its motion is impeded by the auxiliary piston 28, fluid in the space 35 evacuating through the passage 36 and pipe 6. The final closing movement occurs when the trapped fluid is released by the magnet valve 12 which is operated after a predetermined time-lag by a time-switch relay 9 (not shown) brought into operation by the pressure in the pipe 5. Alternatively the magnet valve 12 may be operated by a manual switch. A modified apparatus is described (Fig. 2, not shown) in which the main piston rod moves out of its cylinder to effect the door-opening operation. Two electro-pneumatic control circuits are also described. |
