Abstract: A release mechanism is provided ensuring simultaneous opening of the two clamps of a traction apparatus for freeing the cable which passes therethrough.The release lever is mounted for longitudinal sliding by actuation of the handle while moving the intermediate pin carried by the warping out lever. A pivoting bolt, mounted in a widened end of a longitudinal oblong slit of said lever, prevents the release movement. The release can only be obtained when the user frees said bolt with one hand against the return action of a spring and, with the other hand, operates simultaneously said handle.

Abstract: The hoisting apparatus comprises a device for pressing a roller or a train of rollers against a cable section engaging a driving pulley in order to improve the adherence of the cable to the pulley groove which is caused by the load; this device comprises a linkage fulcrumed at one or more points to the main support of the driving pulley, one end of the linkage carrying the roller or train of rollers while the other end is utilized for anchoring the load to the support.

Abstract: In this cable hoisting apparatus at least two pulleys disposed in a common plane have in the one a semi-circular-sectioned groove and in the other a V-shaped groove section, the first pulley receiving the load and the other pulley being responsive to the tightening mechanism controlled by the load. Thus, the pulley having a semi-circular sectioned groove will not damage the cable and the cable is retained therein by adherence, thus reducing as much the load exerted on the cable section engaging the second pulley, whereby a lesser retaining effort is exerted on this second pulley; when a pressure mechanism is provided for tensioning the cable in proportion to the load, said mechanism is associated with the pulley having the V-shaped groove.

Abstract: The clutch device, adapted to be associated with a traction apparatus provided with a release device comprising two rocking levers, comprises a clutch engaging member associated with one of the rocking levers in order to modify the normal movement of this rocking lever and a clutch control member associated with the other rocking lever and adapted, when actuated, to provide a simultaneous opening of the two clamps of the apparatus.