Patent GB-184968-A (GB)
Title: Improvements in door-operating mechanism
IPC: E05F15/56
Filed: 1921-07-12
Abstract: 184,968. Dehn, F. B., (National Pneumatic Co.). July 12, 1921. Operating and controlling doors electrically and hydraulically.-When a door 5 encounters an obstruction during its closing movement, a valve 38 is positioned to effect a movement of the motor control valve 27 to cause the motor to move the dor towards the open position, and on removal of the obstruction from contact with the front edge of the door the valve 38 is moved automatically into a position to cause a reversal of the operative movement of the motor, the door again continuing its closing movement. In the arrangement shown in Fig. 1, the slidable door sections 5, 6 are operated from a reciprocable cross-head having end pieces 13 connected together by rods 8 located on opposite sides of a motor 10, the members 13 being connected by links 11, 12 to the door-operating levers such as 7. The motor mechanism comprises cylinders 16, 17, the pistons 18, 19 of which are connected to the end pieces of the crosshead. As shown in Fig. 3, the slide-valve controlling the admission of pressure fixed to the cylinders is positioned so that the doors are in the closed positions, the piston 19 being connected to exhaust through ports 24, 28. The fluid pressure is admitted through a pipe 26 to the valve chamber 25, the valve 38 admitting pressure through a pipe 39 to the other side of the piston 31 and maintaining the valve 27 in position for the door to be closed. When it is desired to open the door the switch 45 is operated to close the circuit of the solenoid 43, thus moving the rod 41 to shift the valve 38 into a position to close the passage 39 and open the passage 40. By this means, the cylinder 32 is cut off from the chamber 25 and opened to the atmosphere. The piston 31 is then moved against the spring 33 by pressure in the chamber 25, and the valve 27 is shifted to open the port 24 to pressure and put the cylinder 17 to exhaust. The pistons are then moved to the right-hand side to open the door. The release of the switch not only arrests the door but causes it to be moved again into the closed position through the pilot valve 38 being shifted to its left-hand position by the pressure on the chamber 25. A similar action occurs when the door encounters an obstruction during its closing movement. The front edge of the door 5 is provided with a movable member 46 supported by levers 48, whereby the member 46 is lifted by contact with a passenger. This lifts the link 52, and the link 55 is moved through the link 54 and lever 53 into contact with a lever 56. By this means the valve 38 is moved to the right and the valve 27 is shifted to reverse the movement of the door. As soon as the obstruction is removed and the shoe 46 returns to its lowered position, the lever 56 is automatically released. The pressure in the chamber 25 then acts upon the pilot valve 38 to close the passage 40, thereby again reversing the motor and causing the door to resume its movement toward the closed position. The motor may be locked against operation by means of a rod 91 provided with an arm arranged between the lever 56 and the rod 41 of the solenoid core. The other end of the rod 91 is pivotally connected to a gravity-actuated locking pawl 62, the hooked end of which engages with a lug 64 of the cross-head 13.