GB161702A - Improved construction of portable lifting machines - Google Patents

Abstract

161,702. Collis, A. Jan. 17,1920. Winch-actuated hoists with guided platforms; catch-gear and like safety retaining mechanism.- In stacking-machines, means are provided for raising the platform at one or more speeds, for lowering the platform under the control of a friction brake, for arresting the descent of the platform if the. hoisting-rope breaks, and for cushioning the platform if it falls owing to careless operation. The platform 11 is connected to a frame. 9 having rollers 10 engaging grooves in the uprights 6. The: hoisting-rope 15 is secured to a lug 14 which is connected to the frame 9 by a spring 13. Links 16 connect the lug 14 to pivoted pointed arms 17, which normally are held out of contact with wooden strips.in the grooves in the uprights. If the rope breaks, the spring 13 will pull down the links 16, and the pointed arms 17 will be forced into the wooden strips, thus arresting the descent of the platform. The winding-drum 19 has means for frictionally engaging a worm-wheel 20, and can be engaged by an ajm 22 which is rocked by screw mechanism 24. During lowering, the pull of the rope 15 keeps the drum and worm-wheel in engagement. The worm shaft 27 can be driven directly by the handle 31, or through gearing by applying the handle to the end of a shaft 30. A bellmouthed air tube 33 secured to the platform and having a small hole in the closed top co-operates with a plunger secured to the base 1 and ensures the platform reaching the bottom slowly.