There is disclosed a disc brake for a fluid-operated motor; the brake includes a disc keyed to the output shaft of the motor and sandwiched between non-rotatable plates which are spring-biased to disc braking position. The flexible conduit, which feeds the fluid to the motor, extends between the two plates. When fluid in the conduit is not pressurized, the conduit is flattened and the brake is in braking position, but the brake is released as soon as the fluid is pressurized within the conduit, since the latter takes its normally cylindrical shape and separates the two plates.
An obstacle detector is disclosed, being designed to automatically brake a descending or ascending load suspended on at least two spaced cables, should an obstacle be encountered in the path of the load. The detector comprises at least two winch drums and a rotatable horizontal rod having at least two laterally-spaced levers projecting radially therefrom and inclined on opposite sides of the rod. One end of each cable is secured to a drum, passes through a pulley supporting the load and is secured to a corresponding lever at its other end. A change in the tension of one of the cables, due to an obstacle, results in a small rotation of the rod, thus activating an electric sensing device which effectively shuts down the motor driving the winch drums.
