GB190826553A - Improvements in Hydraulic Machinery for Lifts, Hoists, Cranes and the like. - Google Patents

Abstract

26,553. Hammond, E. N., and Champness, H. Dec. 8. Lifts; hoists ; cranes.-A lift or hoist cage, or a weighted crane hook, is connected by a rope to the piston of a vertical hydraulic cylinder, which piston is so weighted as to overbalance a light load but to be overbalanced by a heavy one, pressure water being required only to raise a heavy load or to lower a light one. The cylinder a, Fig. 1, is fitted with a piston e fixed on a rod b weighted at its lower end. The upper end of the piston-rod carries a sheave around which the cage rope b<2> passes. The balance weights c are sufficient to raise the cage d and a small load, but when the cage is fully loaded it descends by gravity. The working-valve comprises a pair of hollow cylindrical castings through which are passed hollow stems l, l<1>, Fig. 2, with suitable ports p, p<1>, q, q<1>. Sleeves fitted with cup-leathers form water-tight joints with the stems. The supply pipe is divided and fitted into two ports A, A' in the valve casing, the waste water passing out through a central port D. The ports B, C connect up to the upper and lower ends respectively of the cylinder a. With the valve stems l, l<1> in the position shown, the cage is held stationary. If it is desired either to raise a light cage or to lower a loaded one, the stem l<1> is raised so as to connect the ports B, C, thereby allowing water to pass freely from one end of the cylinder to the other, no water being drawn from the pressure main. To raise a loaded cage, the valve l<1 >is placed in the position shown, and the valve l is raised so as to allow pressure water to pass through the ports A, B to the upper end of the cylinder and the waste water to exhaust through the ports C, D. Similarly, to lower a light cage, the valve stem l is depressed.