Patent GB-356788-A (GB)
Title: Improvements in electrical control systems
IPC: B66B1/50
Filed: 1930-05-13
Abstract: - 356,788. Lifts. STEVENS, R, J., Dunoon, Coombe Lane, Kingston Hill, Surrey. May 13, 1930, No. 14728. [Class 78 (ii).] Electric plant.-In an electrical control system for lifts or other apparatus in relative motion, different operations of the control apparatus proper (e.g. floor selecting gear) occur in a predetermined sequence under the control of a relay system operated by the inductive action of a plurality of controlling electromagnets (or inducers) upon one or more pick-up windings on the lift &c. The invention is also applicable to railway trains or reciprocating apparatus such as planing machines. In the lift control system shown in Figs. 1, 2, 3 for three floors A, B, C, the lift may be started in either direction and accelerated through four distinct speed stages according to the setting of a manual controller and then automatically decelerated through corresponding speed stages and automatically brought to rest at the desired floor, the controller being held in its operative position to pass unwanted floors. The lift is controlled by inducers, whose coils are shown in Fig. 1, fixed in appropriate positions in the lift shaft and co-operating with a pick-up coil on the lift. These inducers may be selectively energized in series connected groups of three from supply mains 23. At each floor there are four inducers for each direction of travel, each inducer corresponding to a speed IV, III, II or I. The manual controller, Fig. 2, has four positions IV. III. II and I, corresponding to four speeds, on each side of an " off " position. One side of the " off " position corresponds to the upward direction of travel and the other side to the downward direction of travel. (Normally open contacts are represented by short parallel lines ; normally closed contacts are represented by rectangles with strokes through them; the contacts of the manual controller are indicated by pairs of dots with adjacent rectangles (Fig. 2), the controller positions being represented by dotted lines and Roman figures.) On moving the controller to position I, magnets 25, 28 doum 27 become energized from the mains 29. The magnet 25 opens contacts 25b, Fig. 1, putting all the inducers out of circuit. The magnet 28 down locks up over contacts 28c down and operates the motor to set the lift in motion, while the magnet 27 closes the contacts 27a, Fig. 1. On moving the controller through positions II, III to position IV, the magnets 30, 31, 32 are successively energized closing holding circuits through contacts 30c, 31c, 32c, Fig. 2, and effecting changes in the motor control gear so that the speed is increased. Further, the magnets 30, 31, 32 close contacts 30a, 31a, 32a, Fig. 1, and open contacts 30b, 31b, 32b, Fig. 1, so that the group of inducers IV (A, B, C) corresponding to speed IV down is selected. By moving the controller back to " off," the lift is brought under the automatic control of the controlling electromagnets IV (A, B, C). The magnets 28 down 30, 31, 32, Fig. 2, remain energized owing to the maintaining circuits closed over contacts 28c down, 30c, 31c, 32c, Fig. 2. The circuits of the magnets 33 .. 36, corresponding to the four possible speeds, Fig. 3, on the lift are similarly selectively prepared by contacts 27e, 30e, 31e, 32e, 30f, 31f, 32f, Fig. 3, controlled by magnets 27, 30, 31, 32, Fig. 2. Thus after the cycle of controller movements described, only the circuit of magnet 33 is adapted to be completed by the relay 21. Assuming the lift is to be brought to rest at floor A, when the pick-up coil is energized by the inducer IV A, Fig. 1, it actuates the relay 21 and magnet 33 is energized, locks up over contacts 33e, and opens the contacts 33d, Fig. 2, putting the magnet 32, Fig. 2, out of circuit and reducing the speed of the lift. The circuit of the relay 37, Fig. 3, in series with the magnet 33 is also completed, and the relay 37 is maintained energized by the winding 37a and opens contacts 37f so that the relay 21 cannot energize the magnet 34 whose circuit had been prepared by the closure of contacts 32f, Fig. 3, consequent upon the de-energization of magnet 32, Fig. 2. The pick-up coil passes out of the field of action of the inducer IV A and the relay 21 becomes de-energized, thus de-energizing winding 37a, closing contacts 37f, and selecting magnet 34 to be next energized. The inducers III (A, B, C), Fig. 1, have been put in circuit by the opening of contacts 32a and the closing of contacts 32b, Fig. 1, consequent upon the de-energization of magnet 32, Fig. 2. The speed of the lift is similarly reduced as a result of the energization of the pick-up coil by the co-operating inducers III and II, Fig. 1. Finally the inducer I (A, B, or C) causes the pick-up coil to complete the circuit of magnet 36, Fig. 3, and to open contacts 36d, Fig. 2, breaking the circuit of the magnet 28 down and bringing the lift to rest. In order to pass a floor, the controller is held on one of its operative positions preventing any decrease of speed and also a new selective energization of the controlling electromagnets. The contacts and magnets may be arranged in other ways, Fig. 4 (not shown) illustrating an alternative grouping which comprises a relay, Fig. 5. When the coil 33a is energized, the arm 44 moves to maintain the contact between 44a, 48, .and release a latch 53 opening contacts 33. When the coil 33a is deenergized the arm 44 is pulled over to close contacts 44a, 49. Energizing the coil 50 raises the latch 53 opening contacts 33 and moving the arm 44 to close contacts 44a, 48. In the lift control system of Figs. 6, 7, the lift moves to a selected floor upon depressing a button 83 .. 88, Fig. 7, in the lift associated with that floor. In Fig. 7 the lift is standing at floor 86. Upon depressing a button 84, magnet 84a is energized and locks up over contacts 84b, so that the button may be released. Magnet 91 up is energized through contacts 54, 62, 84b and operates the motor switch to set the lift in motion. After leaving the floor 84, the pick-up coil 77, Fig. 6, is energized by an inducer in the lift shaft and withdraws a pawl 75 from a ratchet 74 allowing shaft 66 to rotate cam arms 67 which engage arms 68 fixed to the contacts 62 .. 65 so that the contact 64, Fig. 8, moves across to meet contact 59. Upon approaching floor 85 the pick-up coil is again energized by an inducer and contact 63 moves to a position midway between contacts 56 and 57. On leaving floor 85 the pick-up coil is again energized causing contact 63 to meet contact 57 and just before reaching floor 84, the pick-up coil is energized causing contact 62 to move to its midposition, breaking the circuit of magnet 91 up and stopping the motor. Contacts 89, 90 are opened when the lift reaches the limits of its travel. Magnets 79, 80, Fig. 7, cause a pin clutch 78 to engage either of the freely rotating bevel wheels 71, 72, Fig. 6, with the shaft 66 so that the direction of travel of the lift controls the direction of rotation of theshaft 66 and therefore the move-, ments of the contacts 62 .. 65. ! For a downward direction of travel, magnets 91 down and 80 are energized. The pick-up coil 97, Fig. 8, is Mounted on the centre limb of an E-shape core, 96. Inducers 93 fixed in the lift shaft co-operate with the limbs of the E-core. The current generated in the pick-up coil before actuating the relay 21, Fig. 3, or the pawl 75, Fig. 6, may be amplified, the thermionic valves of the amplifier having a grid bias greater than is necessary normally to cut off the anode current by an amount which will prevent stray voltages picked up operating the controls.