Patent GB-262854-A (GB)
Title: Improvements in apparatus for operating and controlling the doors of tramway or like vehicles
IPC: E05F15/02
Filed: 1925-09-15
Abstract: 262,854. Peters & Co., Ltd., G. D., and Hockley, H. R. Sept. 15, 1925. Operating and controlling doors electrically and pneumatically. - In a system for operating and controlling the doors of electric tramway cars and similar vehicles a valve device is provided which is controlled by an electromagnet that is normally energized by current from the propulsion current supply, the valve device being so constructed that while the electromagnet is energized compressed air is supplied to the door engines but when it is de-energized as by a failure of the propulsion current the door engine feed-pipe is placed to exhaust on the driver releasing his grip on the appropriate " deadman's " valve of the apparatus. This valve device C contains a solenoid 18 which, when energized by current in the wire 48, opens the valve 17 and permits compressed air from the cylinder 1 to act on the piston 20 and position the slide valve 19 so that compressed air is supplied from a pipe 12 to the door-operating motors to keep the doors closed. On the failure of the current, as by the trolley leaving the wire or the main supply failing, the magnet 18 is de-energized and the valve 17 drops to shut off the supply of compressed air through the pipe 12 and allow the chamber 21 to exhaust through the port 17<a>. The piston 20 is then moved by a spring to the righthand side of its cylinder and the slide valve 19 places the door-feed pipe 22 in communication with the pipe 16. The valve 27 being in the position shown, and the driver releasing his grip on the front " dead-man's " valve 4, the valve 4 moves to place the pipe 16 to exhaust through the rear " dead-man's " valve 5. The doors then become free to be moved by hand if it is necessary for the passengers to escape from the car. When the car reaches the end of its run in one direction, the driver closes the valve 27, after opening the switch 36a and before changing over the trolley pole, in order that the air pressure from the door-feed pipe will not be exhausted. In the general arrangement of the system shown, compressed air is supplied through the pipe 10, 12 to the valve device C, and through the pipe 13, valve 19 and pipes 22, 23 to the door motors 6 - - 9 controlled by valves 6<a> - - 9<a> and operated by valve-pullers 6<b> - - 9<b>. The electrical portion of the control apparatus comprises front and rear change-over switches 36<a>, 36<b>, and air-operated switch D, a switch device E, treadle-operated switches 37<a>, 37<b>, the electromagnetic valve device 18, and electromagnetic valves 6<c> - - 9<c> for controlling the supply of compressed air to the valvepullers. The device E comprises two electromagnets 40, 41 with armatures connected by a floating lever 42, to the centre of which is connected a rod 43 with a contact maker 44, the arrangement being such that contact at 44 is broken if either of the electromagnets 40, 41 is energized by current supplied to the car or by regenerative current supplied by the motors when the car is coasting at not less than a predetermined speed. The apparatus operates as follows :-With the parts in the position shown, assuming the car to be running with the end A leading, air is supplied to all the door engines to hold the doors closed. When the driver shuts off power from the traction motors and applies his brakes, the contact 44 of the device E will close its circuit as soon as the car slows down sufficiently. The driver then releases his grip on the " deadman's " valve 4 to place the pipe 16 to exhaust through the valves 4 and 5. The magnet 18, not being in the traction circuit, remains energized. The cylinder 25 of the device D is put to exhaust and the contacts 39 of the door circuit then close to complete the circuit of the electropneumatic valve 6<c>. This places the valve-puller 6<b> to exhaust, the valve 6<a> is operated, and the door engine 6 operates to open its entrance door. The exit door on that side is operated when a passenger depresses the treadle 37<b> and completes the circuit of the valve device 7<c>, the door closing again after the treadle is released. When the passengers have entered the driver again grasps the " dead-man's " handle to move the valve 4 and cause the motor 6 to close its door. At the end of the run the driver, when he changes ends, proceeds in the manner previously described, the switch contacts 36<a> being broken and the switch contacts 36<b> being made for the operation and control of the doors on the other side of the vehicle, when the end B becomes the front of the car. Specification 254,347 is referred to.