Patent GB-340621-A (GB)
Title: Improvements in or relating to control systems for elevators, hoists, lifts and the like
IPC: B66B1/48
Filed: 1929-10-05
Abstract: 340,621. Lifts. ASSOCIATED ELECTRICAL INDUSTRIES, Ltd., Bush House, Aldwych, London.-(Assignees of Kinnard, L. J. ; 233, N. LaVergne Avenue, Chicago, U.S.A.) Oct. 5, 1929, No. 30265. Convention date, Oct. 6, 1928. [Class 78 (ii).] Electric plant.-A lift for use in department stores and similar service is provided with a control system by means of which it may be operated in either of two manners, (1) in which the lift will travel at the highest speed with which floor-to-floor runs may be made and in which it will slow down automatically as it approaches each floor, and (2) in which the lift will be operated at a higher speed and will be slowed down only at those floors at which the attendant desires to stop. The hoisting drum D is coupled directly to the armature EM<1> of a hoisting motor EM, the control arrangements for which are of the variable voltage type. The direction of excitation current for the field winding GF is controlled by an " up " direction switch 1 and a "down" direction switch 2, and the value is controlled by an intermediate-speed relay 3 and a high-speed relay 4. The operation of the switches 1, 2 is controlled by " up " direction and "down" direction relays 5, 6. The speed and direction relays are controlled by a switch CS mounted on the cage C. This switch has three positions of adjustment for each direction of travel, viz. two running positions and an intermediate or stop position. The system is provided with apparatus for stopping the cage level with the floors of the automatic inductor landing type and includes an up intermediate-speed inductor relay SU, an up high-speed inductor relay HU and a stopping inductor relay S for causing the cage automatically to be retarded from its intermediate and high speeds, respectively, and brought to a stop at an exact level with a floor when the cage is travelling upwards. Similar relays S, SD and HD are provided for causing the cage to slow down, &c., when the cage is travelling downwards. Each floor has a set of inductor plates co-operating with the inductor relays, e.g. the second floor has a stopping inductor plate S<1>, an up intermediate-speed inductor plate SU<1>, and an up high-speed inductor plate HU<1>, and similar plates SD<1>, HD<1> to operate the relays SD, HD when the cage is moving downwards. If the cage is at the bottom floor and the switch CS is moved clockwise to engage the contacts 14, 15 and 16, the up-direction relay 5 is energized and completes a circuit which energizes the up-direction switch 1. A self-holding circuit is completed by the energization of the switch 1 which keeps it in operating position until the inductor relay S is actuated to open its contacts. The actuation of the switch 1 completes a circuit for supplying current to the field winding GF of the generator G, and consequently the cage starts at very low speed. When the switch is moved to engage the contacts 45, 15 and 16, the intermediatespeed relay 3 is energized and on the closing of its contact members b, the section 34 of a resistance is shunted and the cage travels at a higher speed. The closing of the contact members a completes a self-holding circuit. A segment 49 electrically connected to the segment 15 of the switch CS is arranged so that when the switch has been moved to engage the segment 15 and contact member 45, the segment 49 will engage the contact member 50 but will be out of engagement with the contact member 51. In consequence the intermediatespeed inductor relay SU will be energized. As the cage approaches the second floor, the relay SU is brought adjacent to the inductor plate SU<1>, and its contact members 40 are opened and the relay 3 de-energized. Thereafter the cage approaches the second floor at a slow speed. If it is desired to stop there, the switch CS is centred which operation causes the energizing of the coil of the stopping inductor relay S. The contact members 19 of this relay will be opened when adjacent to the inductor plate S<1> and the holding circuit for the up-direction switch 1 broken. If it is not desired to stop, the switch CS is kept in its adjusted running position in which the contacts 15, 45, and 16 are in engagement, and the cage will again accelerate to intermediate speed. The energizing circuit for relay 3 extends through the normally closed contact members b of the counter e.m.f. relay CEMF which is so selected that its contact members open only while the cage is travelling at greater than landing speed. If the cage slows down to landing speed, the energizing circuit for relay 3 will again be closed through conductors 42, 43, 44 and contact 45, but as soon as the speed of the cage becomes greater than landing speed, the relay CEMF opens its contact members and places relay 3 under the exclusive control of the inductor relays SU, SD. If it is not desired to slow down at each floor, the switch CS is moved to the third or continuous running position to energize the highspeed relay 4. In this position the segment 49 is out of engagement with either of the contact members 50, 50<1>, and consequently the closure of the energizing circuit for the coils of the relays SU, SD is prevented. When relay 4 is actuated, its contact members b will shunt resistance 35 from the field-winding circuit, and its contact members a will complete a self-holding circuit.