Patent GB-182690-A (GB)
Title: Improvements in electrically controlled fluid-pressure-actuated motors, for operating doors, gates, and other like members
IPC: F03C1/00
Filed: 1921-07-12
Abstract: 182,690. Dehn, F. B., (National Pneumatic Co.). July 12, 1921. Retractive switches; contacts; fluid actuation.-A fluid pressureactuated motor, more particularly for operating doors, gates, and like members, comprises electromagnets 11, 12 in normally open circuits for opening and closing valves 8, 9 controlling the supply of fluid pressure to the opposite ends of a motor cylinder. 6, 7. push-buttons 19, 20 for closing the circuits of the electromagnets 11, 12, the momentary closing of either of these circuits also causing the operation of one of the solenoids 29, 30, and associated armatures 31, 32, whereby the operating circuit is maintained closed until the operation of the motor is completed or until the other push button is operated. Within the cylinder for operating the door, &c. is a double piston 1, 2 the ends of which are connected by a rack 3 gearing with a toothed segment 4 on a shaft 5. When either of the pistons 1, 2 is moved to the end of the cylinder, the segment 4 is rotated into a position whereby one of the members 17, 18, engages with a projection 16 on the pivoted switch member 13, which is thereby rocked to move the contact members 14, 15. This breaks the circuit of the electromagnet 11 or 12 which has been maintaining open the valve 8 or 9 to supply fluid pressure to the motor. In Fig. 1 the mechanism and switch members of the circuits are represented in the position when the motor is in an intermediate position. To open the door, the push button 20 is first depressed. This completes the circuit from the positive main 40 through switch members 26, 25 and electromagnets 29, 11. At the same moment as the valve 11 is opened, the electromagnet 29 moves its armature member 31 to complete a secondary circuit from the positive main through the contacts 33, 24, 23 and the contacts 39 bridged by a member 37 on the arm 36 of the car controller. The closing of this secondary circuit ensures the completion of the opening movement of the motor even if the push button be closed momentarily. This opening movement may be arrested either by moving the control lever 36 to the position shown, or by the stop member 18 contacting with the switch 13 when the door has completed its movement, or by the depression of the button 19. In the latter case, in addition to breaking the secondary circuit which is energizing the magnets 29, 11, the bridged contacts 27, 28 allow current to pass from the positivemain to energize the electromagnet 12, whereby pressure fluid is admitted to the other end of the cylinder and the operation of the door reversed. At the same time, the electromagnet 30 moves its. armature 32 on to the contact member 34, and a secondary circuit is thereby completed from the positive main through the contacts 22, 21 to maintain the valve 9 in the open position. This. secondary circuit does not include the contacts. made by the car control lever 36, as this is not a necessary precaution for the operation of closing the doors. In the arrangement shown in Fig. 5, the door is provided with a pivotally-mounted shoe member 57 whereby, when an obstacle is encountered, a rod 62 carried by links 63 is lifted to move the arm 67 away from the contacts 68, 69 in the secondary opening circuit and into engagement with contact members 70, 71 connected respectively with the main source of supply 40 and magnet valve 11, reversing the closing operation of the door. These contacts may be arranged so that the door again moves automatically towards the closed position when the obstruction is removed.