GB590403A - Fluid-operated hoists - Google Patents

Abstract

590,403. Fluid-pressure-actuated lifting- apparatus. SMALLPIECE, C. D. P. April 20, 1945, No. 9931. [Class 78(ii)] A hoist comprises a piston operating in a fluid-pressure cylinder, a pulley or pulleyset secured to and within the cylinder beyond the limit of the piston travel on the piston rod side of the piston, a pulley or pulley-set carried by the end of the piston rod remote from the piston, and a hoisting wire or the like which is anchored at one end adjacent the pulley-set which is secured to the cylinder, and after being passed round both pulley-sets, passes from the cylinder for connection to a load. In the embodiment shown, the hoist comprises a cylinder 11 suspended from a cable by arms 15 and provided with a piston 18 operating by compressed air in its left-hand portion. In the cylinder just beyond the limit of travel of the piston is secured a block 25 carrying pulleys 27, 28. The piston is provided with a block 31 to which is secured a piston rod comprising strips 34 extending on opposite sides of the block 25 and connected by a screw 35 to a block 36 on which is secured a disc 37 forming a cross-head. Pulleys 40, 41 are supported on the piston rod by a pin 39. The hoisting wire is secured at 46 to the block 45 and after passing round the two sets of 'pulleys, passes out through a hole 49 in the cylinder. The hoist is controlled through a valve body 50 secured to the cylinder 11 and housing an inlet valve which is connected to the cylinder 11 and operated by a hand lever. A release valve is housed in the handle of this hand lever and operable by the handle.