GB454492A - Improvements in or relating to the control of electric lifts - Google Patents

Abstract

454,492. Lifts. HAMMOND, E. N., 26, Fordhook Avenue, Ealing Common, and POLLARD & CO., Ltd., E., St. John Street, both in London. March 27, 1935, No. 9599. [Class 78 (ii)] [See also Group XXXVII] In a lift control system, the car switch comprises a manually operated selector switch which is movable to any one of a number of positions to cause the lift to move to a selected floor and is provided with a number of illuminated indicator windows corresponding to the floors and co-operating with a screen movable with the manual operating member of the switch. As shown, the car switch comprises a contact arm 12 movable into engagement with any one of the contacts 8.. 11 corresponding to the lift stations. Groups of floor selector switches 2a, 3a, 4a ; 1b, 2b, 3b corresponding to the " up " and down " movement of the lift respectively are operated by the lift, the switches being interlocked or operated so that when any floor switch is closed, the corresponding switch for the other direction of motion is opened. The floor switches are connected to the up and down main contactor coils 5, 6 which when energized, start the motor in one or other direction. When the car is at the ground floor all the switches 2a, 3a, 4a are closed and any destination may be selected by moving the arm 12 into engagement with the appropriate contact 8-11. The motor is then driven until the corresponding floor switch is operated. Similar operations occur for the downward movement of the lift. Moreover, the direction of movement may be reversed after a selection has been initiated. The width of the contact on arm 12 is such that at least one contact 8-11 is always engaged so that smooth operation may be effected. Fig. 3 shows the control switch, two rows of indicating lamps 19, 20 being provided, the row 19 being operable by call switches provided at the corresponding floors, and the other row 20 being provided to indicate to the attendant whether the control switch has been positioned to effect the proper floor selection. The lamps in the first row may be coloured green and a green disc 22 mounted on the control handle of the switch 15 co-operates with the second row of lamps. The second row of lamps may be omitted and in this case the disc co-operates with the first row. In a modification, provision is made for slowing down the lift upon approach to a selected floor. The control switch has additional contacts interconnected with further floor selector switches which are operated in advance of the main floor switches and the arrangement is such that a control resistance is switched into the motor circuit when the lift approaches a floor. Further means may be provided to maintain the speed of the lift constant. Specification 436,309, [Group XXXVII], is referred to.