GB1399936A - X-r'' ''tensifying foil or fluoroscopic screen - Google Patents

Abstract

1399936 Lift door operation OAKLAND ELEVATORS Ltd 15 July 1973 [19 Aug 1972] 39051/72 Heading B8L A lift door operator assembly for controlling the vertical opening and closing movement of a lift car door 30 together with an adjacent lift shaft door 39, comprises an electromagnet 22 mounted on the car door 30 and energizable to couple the door 30 to a pick-up plate 37 on the shaft door 39, an electric motor 1 for reciprocably driving a car door driving pin 14 and safety switches 20, 32 on the car door 30 to sense relative movement between the driving arrangement and the car door generated by the baulking of the closing movement of either door, while the electromagnet is energized, to initiate reversal of the closing movement of the drive arrangement. The pin 14 is journalled in endless chains 12 driven through a chain 6 and sprocket transmission from the motor 1, all mounted on the lift car roof, whereby the pin 14 is reciprocated up and down to open and close the doors. One end of the pin 14 is received in vertical slots 23a in a bracket 23 secured to the top of the car door 30 and during lifting the pin reacts against the top of the slots. The electromagnet 22 is supported on an arm 25 pivoted at 25a to a pivot block 28 on the door 30, and is shaped to have an inclined ramp 25b engageable by the drive pin 14 when it moves downwardly in the slots 23a from its normal driving position, to retract the electromagnet 22 from its operative position, a projection 24 also on the arm 25 actuates a switch 16 to stop the motor 1 when the magnet is retracted. In operation, when the doors are selected to open, the motor 1 is started and the magnet 22 is energized and moves to engage the shaft door 39, the drive pin 14 engages the upper end of the slots 23a and both doors rise until a cam track 31 on the car door 30 engages a switch 10 to de-energize the motor 1 only. When the doors are selected to close, the motor 1 is energized in reverse and the pin 14 lowers the doors until the cam track 31 engages a switch 18 which de-energizes the magnet 22 and changes the circuit so that the lower safety switch 20 becomes inoperable and cannot re-open the doors. As the doors reach their lowered position, the pin 14 moves down the slots 23a causing retraction of the magnet and causing projection 24 to de-energize the motor through the switch 16. If during lowering, the shaft door 39 is baulked the motor reversing switch 32 is operated by a cam 27 on the block 28 which moves against spring bias relative to the bracket 23. If the car door 30 is baulked during lowering the motor reversing switch 20 is operated by a cam 15 on the pin 14 which moves against spring bias relative to the bracket 23. A switch 35 on every shaft door 39 must be closed before the main hoist drive motor can operate and this switch also opens the magnet circuit to permit retraction thereof.