GB345035A - Improvements in or relating to safety apparatus for elevators and the like - Google Patents

Abstract

345,035. Catch gear and like safety retaining - mechanism. ASSOCIATED ELECTRICAL INDUSTRIES, Ltd., Bush House, Aldwych, London.- (Assignees of Dunlop, J. ; 513, South Prospect Avenue, Park Ridge, Illinois, U.S.A.) Feb. 6, 1930, No. 4048. Convention date, Feb. 6, 1929. [Class 78 (iii).] Safety apparatus for braking a lift cage C when the speed becomes excessive comprises pairs of co-operating jaws 18, 19 adapted for relative movement to grip guide rails 11, push rods 37, 38 for operating the jaws, nuts 23, 27 into which the rods are screwed and which are provided with co-operating cam ends 65, 66, and a drum 20 connected directly and through gearing to the nuts 23, 27, respectively, and which is normally stationary but to which rotational movement is imparted when the speed of the cage becomes greater than a predetermined value. The jaws &c. are mounted on a framework 17 connected to the bottom of the cage through dashpot mechanism 15. The jaws are closed on the rails by the outward movement of cam-shaped members 43, 44 on the rods 37, 38 and are retracted by springs 49, 50 when the members 43, 44 are withdrawn. The drum is rotated by a rope 55 which is secured to the governor rope 14 by a clamp 58. The rope 14 is attached to the cage by a yielding connection 60 and passes over a sheave 61 which is geared to a centrifugal governor 62. When over-speeding occurs a cam lever 63 actuated by the governor locks the rope 14, the connection 60 is broken, and as the cage continues to descend the rope 55 is pulled away from the drum 20 thereby rotating it and causing the application of the jaws 18, 19 to the guides. The dashpot mechanism 15 comprises a plunger 73 secured directly to the bottom of the cage and extending into a cylinder 74 secured to the frame 17. A central aperture 75 in the plunger 73 permits the liquid in the cylinder 74 to flow into a cylinder 76 and move outwardly a pair of pistons 77, 78 which actuate auxiliary gripping-jaws 18<1>, 82. The rope is rewound on the drum by rotating it by means applied to the bevel gear 59.