Patent GB-444718-A (GB)
Title: Improvements in door operating apparatus
IPC: H02P7/00
Filed: 1935-04-01
Abstract: 444,718. Door - operating apparatus. NATIONAL PNEUMATIC CO., 420, Lexing- ton Avenue, New York, U.S.A. April 1, 1935, No. 10133. Convention date, April 26, 1934. [Class 65 (i)] In an electrical control system for a number of vehicle doors operated by individual reversible motors, one or more of the motors are arranged to be directly energized and such energization causes the preparation of circuits for one or more other motors, which are completed by independently - operated means, such as a passenger-operated treadle. The latter motors are automatically reversed for closing, and are also automatically reversed when the closing of the doors is obstructed ; means may be provided for direct control of these motors. All the motors operate means which slow them down at the end of each movement. In the arrangement shown, two pairs of folding doors 21 and a single folding door 21<1> are provided, each door having an individual motor 2 or 2A which also operates a drum switch 62 ; the motors 2 of the doors 21 are controlled by individual hand-operated switches 53, and the motor 2A of door 21<1> is controlled by a relay 78. In the position shown, the doors are all closed ; the field of each motor is in series with a resistance 24, with a shunting resistance 25, and this combination is in series with the armature, which is shunted by a resistance 26 switched in by 62 near the end of the closing movement to slow down the motor and hold the door closed. In opening, the field is reversed and connected in series with resistance 25, these being shunted by 24, and 26 is switched in near the end of the movement in the same way as in closing. The motors of the central pair of doors operate switches 64, in addition to 62, these switches being connected through treadle switches 74 so that when either centre door is open and a treadle is depressed by a passenger the door 21<1> is opened. The motor 2A operates a drum switch 30 which, in the opening movement, breaks at R the circuit 32 to the controller of the traction motors of the vehicle and to an indicator 34 and closes at S a circuit direct from the main switch 27 to the treadle switches 74 and also through a resistance 85 in parallel with 74 to the relay 78 ; the lower pair of fingers T are also connected during the greater part of the stroke. The connection at S to 85 is broken in the fully open position of the door, so that if the treadles are unoccupied the relay receives no current and the doors close. A switch 89 on the edge of the door is operated if the door strikes any obstruction in closing to complete a circuit for the relay 78 to reopen the doors ; near the closed position, switch 89 is disconnected from the relay at T, but is connected to an alarm 94 which is thus operated if anything is caught in the closed door. The door 21<1> may be opened independently of the centre doors by push-button 71, the operation being otherwise similar ; this control and that by the centre doors may be cut out by switch 70, and the door 21<1> may then be operated by switch 92 without any treadle or other automatic control. Electrical control of all the doors may be interrupted at 28, switch 36 being then operated to supply the vehicle controller. The Specification as open to inspection under Sect. 91 also describes an electric motor for operating folding doors by means of an internally-threaded hollow armature shaft engaging a screw spindle fixed to a cross-head which is linked to a crank on the shaft carrying the door. This subject-matter does not appear in the Specification as accepted.