[ Power-operated lifting equipment, machines, and devices, namely, ] hoists and winches; effort alleviation devices, in particular for weight relief, comprising a belt, a driving engine, a control for said engine, and a pulley, namely, equipment designed to assist an operator for going up and down a ladder or similar structure, said equipment fitted on said ladder or similar structure, comprising a motor, a belt passing around an upper and a lower pulley, one of such pulleys being connected t...