PORTABLE MULTI-STAGE MECHANICAL LIFT UNIT

摘要

1499695 Elevator or catch gear S W BUSHNELL JR 23 March 1976 [4 April 1975] 11646/76 Heading B8L An elevator comprises a carriage 28 movable vertically along an upper section 27 of an extensible mast 25, 26, 27, the movement of the carriage 28 and the movements of the upper mast section 27 along the intermediate mast section 26 and the latter along the lower fixed mast section 25 being effected by a cable 79 reeved over sheaves 80, 81, 82, 83, 84, 85, between an operating winch 34 and a dead ended fixture on the carriage 28 or upper mast section 27. Each of the sheaves 85, 83 and 81 on the carriage 28 and at the lower ends of the mast sections 27, 26 respectively, is associated with a locking arrangement whereby slackening of the cable causes the carriage to become locked to the upper mast section 27 which becomes locked to the intermediate mast section 26 which becomes locked to the lower mast section 25. Each locking arrangement comprises a pivotal latch 100 rotatable according to the position of the associated sheave 83 which when the cable 79 is tensioned, is slid into an upper position in which the latch is moved by a rod 108 into its full line unlatched position shown, and when the cable slackens, is slid under the pressure of a spring 113 into a lower position whereupon the latch is pivoted into the latched shadow line position shown. The latch 100 in its engaged position is located in one of aseries of openings 102 in a locking channel extending along the front face of each mast section. Each rod 108 is pivoted to a latch 100 and extends downwardly through a slide plate 110 on which the sheave 83 is mounted, a nut 120 at the lower end of the rod being engageable by the plate 110 to move the latch into locking position as the sheave is lowered and a spring 109 around the rod moving the latch into its unlocked position upon upward movement of the sheave. The interengaging mast sections form channels therebetween for receiving guide rollers, and wedge stops are formed in the channels to limit the relative movements. The cable sheaves are arranged on the mast with some parallel and some oblique to the front faces of the mast sections to guide the cable between sections. The upper end of the cable 79 may be coupled to a hand winch 42 on the carriage 28 whereby elevation may be controlled from the carriage 28 or from the ground by the winch 34. The elevator is mounted on casters 9, 13 and is adjustable on jack feet at the ends of outriggers 18, 20. For transport, the outriggers and front casters carrying supports 12 are moved into stowage positions and the lowered elevator is tipped on to transport wheels 11, 35.