Patent GB-776655-A (GB)
Title: Improvements in means for automatically opening and closing doors
IPC: E05F15/02
Filed: 1953-09-28
Abstract: 776,655. Door operating-appliances. AKTIEBOLAGET HAGGLUND & SONER. Sept. 28, 1953 [Sept. 29, 1952], No. 26636/53. Class 65 (1). [Also in Group XL (b)] In a system for controlling the doors of passenger vehicles, the opening of the door is controlled by the operation of the throttle pedal and the interruption by a passenger of a beam of light passing to a photo-electric cell. In response to the " stop " signal 10, the driver operates contact 12 to energize the upper winding of relay 7. This energizes solenoid 02, to actuate the brake locking valve, lamp 8 and photo-cell 9. With the photo-cell illuminated action on the door-operating mechanism takes place, but when a passenger interrupts the beam, the relay 16 operates, lights lamp 5 and energizes door-opening solenoid O1. When the passenger has left, the relay falls back sluggishly owing to the effect of a dashpot 15 and ultimately operates door-closing solenoid S1. Operation of the accelerator pedal completes contact 13 to energize brake-releasing solenoid S2. In case the bus is so full that the light beam from 8 is permanently interrupted, a supplementary lamp (not shown) in the photo-cell casing can be operated by the driver to enable the doors to be shut. To ensure that the door does not close while the passenger is still on the bus, the lamp and cell are arranged on the same side of the doorway and the light beam is reflected by a pair of mirrors so as to follow parallel paths some distance apart so that the passenger continues to break the beam until he is clear of the bus, Figs. 4 to 6 (not shown), for folding doors. In a modification for hinged doors, two lamps are provided, Fig. 7 (not shown). In a further modification, Figs. 13a, 13b (not shown), for an entrance door the lamp and one reflector are moved outwards from the door when the brake pedal is pressed. In the arrangement, Fig. 8 (not shown), solenoids 02 and S2 for locking and unlocking the brakes are omitted but a solenoid energized when the photo-cell is obscured prevents depression of the foot throttle, while in the arrangement of Fig. 7 (also not shown) the throttle is locked by a pressure cylinder in hydraulic parallel with the door cylinder. The door may have an additional switch to make it open automatically if a body gets caught. by it, Fig. 11 (not shown). This switch may consist of two strips set in the door which make contact when a rubber bead in the edge of the door encounters an obstruction. This switch is put out of action when the door is closed by a further switch actuated by the door itself. In the arrangement of Fig. 14 (not shown) an auxiliary switch is provided outside the vehicle to permit intending passengers to open the doors when the driver has operated his. contact 12 (Fig. 1) to energize the brake. The doors are then maintained open by passengers entering until the light beam is again uninterrupted. In the arrangement of Fig. 15 (not shown), the system of Fig. 14 is modified to allow the same door to be used as either an entrance or an exit. This is effected by a change-over switch supplying either a light source and photo-cell inside the bus or else the other source and cell and passengers' switch outside. In the arrangement of Fig. 16 (not shown) the supply to the photo-cell and door controlling mechanism is closed by the driver by means of a change-over valve which actuates the brake and which is coupled to a contact for energizing the photo-cell circuit. Depression of the throttle subsequently energizes a solenoid which changes over the valve to release the brakes and de-energizes the photo-cell circuit. In a modification of this arrangement, Fig. 17 (not shown), the valve is operated by a reversible electric motor.