GB293739A - Improvements in, or relating to, lift safety devices - Google Patents

Abstract

293,739. Coates, A. F. March 19, 1927. Lift cages and doors, locking and unlocking and operating. -Lift door locking devices of the kind in which a horizontally pivoted controlling bar arranged below the top of the door and normally holding it closed, while being raised above the door when it is opened, have the horizontal portion of the controlling bar arranged between the pivotal axis of the bar and the door. As applied to swinging well doors 1, 2, the controlling bar 3 is carried by arms 4, 5 at its ends mounted on pivots 6. A hinged arm 6', Fig. 4, mounted on a pivot 7<1> in the lintel has a slot 8 engaging the controlling bar 3 and a tooth 9 engaging a projection 10 on a bracket mounted on the door. When the door is opened the projection 10 pushes up the arm 6<1> and so raises the bar 3 above the top of the door. The upward movement of the bar 3 about its pivot 6 causes a second arm 12 carrying a bridging contact 14 to open a switch 16 in the electrical circuit of the lift. To allow the door to be opened, a third arm 18, normally locked by a lever 19, is first freed by a ram 21 on the cage engaging a shoe 20 connected by a spring-pressed rod 22 to the locking door 19. To maintain the controlling bar 3 above the doors, the arm 5, Fig. 7, has a second arm 33 with a recess 39 adapted to engage a spring-pressed catch 35 when the bar is raised. A modified bar operating device comprises a bracket 28, Fig. 10, mounted on the door and having a recess 31 for engaging the bar 3 and a roller 29 for operating it. As applied to sliding doors, the bar 3, Fig. 13, has an inclined cam slot 42 within which engages a roller 43 on one half door 49, the other half door 48 carrying a stud 53 normally abutting against a stop ledge 50. When the door 49 is opened the roller 43 acting on the cam slot 42 raises the bar 3 so that the stud 53 is free of the stop 50 and the door 48 can be opened, the stud sliding in a slot 51 in the bar. The invention can be applied to cage doors. Specification 261,828 is referred to in the first Provisional Specification.