GB496536A - Improvements in and relating to safety apparatus for elevators - Google Patents

Abstract

496,536. Safety catch-gear for mine cages. WAYGOOD-OTIS, Ltd. May 11, 1938, No. 14031. Convention date, July 2, 1937. [Class 78 (iii)] In safety catch-gear for lifts, the appliances which grip the guide rails are arranged between the arms of a U-shaped spring and act to spread the arms of the spring apart on being moved into gripping position. In the form shown, on overspeed of the descending cage, the governor 27 releases the catch 45 and allows the cam grips 33, 34 to retard the rope 21 sufficiently to cause it to pull the levers 48, 55 upwards, thus applying an upward pull to wedges 63, Fig. 2, through the medium of links 62. Initially these wedges slide freely over the rollers 68 until they touch the guides 15, after which the roller - carrying frames 69 move upwards between the wedge - shaped surfaces 80 and in so doing distort the horizontally - arranged arms 115 of the U-shaped spring outwards, thus causing added pressure of the wedges 63 against the guides by reaction. Stops prevent upward movement of the frames 69 beyond a certain limit. When hoisting re-commences, the members 80 are hoisted with the cage, but the frames 69 tend to lag owing to their frictional engagement with the wedges 63. In consequence, the rollers 68 roll down the members 80 and relieve the pressure on the U-shaped springs, so that the wedges are released from the guides, and the frames 69 are restored by their springs 95 to their lowest position. The latching-mechanism 45 is then re-set by hand.