Hydraulically actuated lift - has counterbalance weights raised and lowered by second hydraulic cylinder

摘要

A lift (2), for passengers or goods, is actuated by a hydraulic cylinder (1) and ram (3). The cylinder (1) is connected by a pipe (8) to a pump (10) which is in turn connected to a second cylinder (6). This second cylinder is fitted with a ram (3') to which a fixed counter-balance weight (5) and an adjustable balance weight (13) are attached. When the lift (2) is raised the hydraulic cylinder (1) is supplied with hydraulic fluid from the pump (10) which is driven partly by the motor (M) and partly by hydraulic fluid forced out of the second cylinder (6) by the descent of the counter-balance weights (5,13). When the lift (2) descends the counter-balance weights are raised and the direction of rotation of the pump (10) is reversed. USE/ADVANTAGE - The energy needed to operate the lift is reduced.