Patent GB-1007130-A (GB)
Title: Door control means
Inventor: BRUNS WILLIAM HENRY
IPC: B66B13/26
Filed: 1962-07-09
Abstract: 1,007,130. Door operating appliances. OTIS ELEVATOR CO. July 9, 1962, No. 26296/62. Heading E2M. [Also in Divisions G1 and H2]. A door control means for an elevator closure comprises a door operating motor DMA for supplying movement to a door, a first switching means DO effective upon actuation to supply energy to the motor DMA, to effect an opening movement of the door and a second switching means DC effective upon actuation to supply energy to the motor to effect closing of the door, a door protective device CA, DPT which is responsive to pressure of an object in or near the closing path of the door and upon actuation becomes effective to stop the door closing movement and to initiate actuation of the first switching means DO to effect reversal of the direction of door travel to its opening direction, a storage means QZ having a supply of electric energy and electronic switch means TBI responsive to actuation of the protective device to supply the energy stored in the means QZ to the motor in a direction corresponding to opening movement of the door prior to actuation of the first switching means DO in response to actuation of the protective device whereby to cause the motor very quickly to stop closing movement of the door prior to the first switching means DO supplying energy to the motor to ensure re-opening of the door. In the embodiment described the elevator serves a plurality of floors and the motor DMA operates several doors at each floor landing. The switching means DO, DC form part of motor control circuits so arranged that the doors open automatically when the elevator car stops at a landing and commence to close after a predetermined interval. The detecting means are part of a protective circuit as disclosed in Specification 711,515 the means being three cold cathode gas discharge-tubes DPT1-3 the control electrods of each tube being connected to an individual antenna and an object in or near the path of the door increasing the capacity to earth and so causing one or more of the tubes to conduct, This causes a pulse in a transformer TR in the common cathode circuit of the tubes, the pulse being applied between the control electrode and cathode of a thyratron gas discharge tube TB1 to cause it to conduct and discharge a condenser QZ through the armature of the door operating motor DMA in opposition to the current which is causing the motor to turn in the door closing direction. Hence the closing movement of the doors is stopped very quickly. The current through the operating tube DPT also energizes a relay DP which deenergizes the switching means DC and energizes the switching means DO so that the doors are caused to move in opening direction after they have been stopped by the thyratron pulse. They move in the opening direction for a time which is determined by a delay circuit NT, QNT, RNT1. They then stop for a short time determined by a delay circuit DS, QCZ, RG and afterwards move in the closing direction again. If the object should still be in or near the path of the doors the thyratron is pulsed once more and the sequence is repeated. When the doors reach a predetermined distance from their fully closed position the door opening circuit is disabled by a door operated switch and relays and an object in or near the path of the doors then only causes them to stop; they do not reopen. A time delay circuit is also provided which if the doors are still open at the expiry of a predetermined time disables the door opening circuit and closes the door closing circuit; in this case also the protective circuit remains operative to stop the doors if an object is in or near their path. In this case if desired resistances are switched into the motor circuit to close the doors more slowly than usual. Instead of using a protective circuit which requires a change in capacity to cause operation other forms of protective circuit including those which require contact with the object can be used. Instead of using thyratron tube TB1 to discharge the condenser QZ, two thyratrons may be used, these are arranged to bridge the contacts of the switching means DO which when closed supply current to the motor DMM. When the thyratrons conduct they complete the circuit to the motor and the current which flows is in opposition to that through the closed contacts of the switching means DC. If desired the dooroperated switch which disables the dooropening circuit can be positioned so that the doors do not open when an object is detected but merely stop momentarily.