Patent GB-655904-A (GB)
Title: Improvements in or relating to safety locks for lifts
IPC: E05B65/00
Filed: 1948-08-09
Abstract: 655,904. Locking lift-gates. CARTA, V. Aug. 9, 1948, Nos. 20993, 20994 and 20995. Convention dates, Aug. 9, 1947, Oct. 13, 1947, and Feb. 17, 1948. Addition to 655,903. [Class 78 (iii)] An improvement in or modification of safety locks according to the parent Specification for the lattice gates or doors of shafts for electrically-operated lifts comprises a locking bolt causing the closing of the electrical circuit controlling the lift, two locking devices adapted to act alternately, one of which by mechanical action keeps the lock closed when the cage is not opposite the corresponding lattice gate and is alternately removed from and returned to the locking positions by a cam fitted to the cage, the cam being so shaped as to bring the mechanical locking device into and out of the locking position, and the other of which by electromechanical action keeps the lock closed only during the instant when the cage is passing the corresponding lattice gate or door and is alternately brought to and removed from the locking position by means of the core of an electromagnet which, when the coil is energized by the current controlling the lift brings the electromagnetic locking device into locking position, and which when the coil is energized by only a small part of the current, removes the electromagnetic locking device from the locking position; an auxiliary stopping member manually operated from inside the cage, to lock the bolt when the lift is out of operation, and means to render self-acting the closure of the lock, the lock being applicable either to winged or sliding lattice gates or doors. The locking bolt 1 rotates about a pivot 2 and has teeth 3 and 4 at one end engaging a lever 12 and a tooth 5 at the other end engaging with a tooth 6 of a lever 7 rotating about a pivot 8. The bolt 1 closes the electrical switch 9 for the elevator circuit. One end of the lever 12 is forked to engage a pivot 13 on a sliding rod 14, one end of which projects beyond the edge of the door under the action of a spring 17 connecting the lever 12 with the lock as a self-locking device. A member 18 guides the bolt during its movement which is limited by stop 19. In the closed position a pendulum 20 turning about a pivot 21 engages the bolt when a roller at the end of an arm 22 of the lever passes between ribs fitted to the side of the elevator. Insulated on the pendulum is a switch 25 which closes, in short-circuit, the poles 26 of the winding of an electromagnet 27 in the operating circuit of the elevator. When the cabin passes the door the pendulum 20 is raised, the electromagnet is excited to its core between tooth 30 of the lever 7 and an abutment 31, immobilizing, by means of the lever 7, the bolt 1; this prevents anyone opening the door at a level at which the elevator does not stop. On the lever 7 is a switch 91 closing electrical contacts 11<1> instead of the contacts 9 and 11 shown in the parent Specification. An auxiliary stopping sector 37 prevents the elevator from being entered even when at the desired floor. Sector 37 has two switches 33 and 34, one operating through contacts 36 in an electrical circuit which operates the elevator from outside the shaft and the other by means of contacts 35 in a signalling circuit. The drive of sector 37 may be manually effected from inside the cabin. For sliding doors the spring 17, the lever 12, the rod 14, and the abutment 19 are omitted. In the form shown in Fig. 4, the spring-urged locking bolt 50 slides horizontally and the head has a chamfered face for swing doors. The head engages two disc levers 57, 571 having teeth 58, 581 which engage grooves in contact lever 59 as well as in locking lever 60. A pendulum 78 with switch 62 presses on the lever 60. Lever 59 carries switch 63 closing contacts 64 of the elevator operating circuit having an electromagnet 65 the core of which rotates lever 69, the tip 70 of which moves between fixed abutment 71 and lever 59 when passing a door. An auxiliary stopping sector 72 has two switches 74, 73 for operating the electrical circuit of landing push-button switches and for signalling that the elevator cannot be used momentarily. On de-energizing the electromagnet the bolt may be operated outside the shaft by a key or handle 77.