Free rotation control apparatus for a hoist and traction machine

In a hoist and traction machine provided with a load sheave;

• a driving shaft provided with a driven member and for driving said load sheave;
• a driving member threadedly engageable with said driving shaft;
• a braking pawl and a braking ratchet wheel engageable with said braking pawl and braking plates, interposed between said driving member and said driven member and constituting a mechanical brake;
• and driving means for driving said driving member rotatably in a first direction or in a reverse direction of rotation;
• a free rotation control apparatus which allows said mechanical brake to be not-operable and said load sheave to be freely rotatable, provided with
• a) a stopper at an axial end of said driving shaft,
• b) an operating handle for free rotation operation, which is interposed between said stopper and said driving member so as to be axially movable across a first position where said operating handle moves toward said driving member and a second position where said operating handle moves away therefrom and being not relatively rotatable with respect to said driving shaft,
• c) an elastic biasing member interposed between said stopper and said operating handle and for biasing said operating handle toward the first position where said operating handle moves toward said driving member,
• d) regulation means which is provided between said operating handle and said driving member acting to regulate a relative rotation range of said driving member with respect to said driving shaft when said operating handle is put in the first position, and can release regulation when said operating handle is put in the second position, and
• e) free rotation holding means having resistance means which has free rotation control surfaces which, when said operating handle is put in the second position to release the regulation and rotates for free rotation operation, applies to said driving member a biasing force by said elastic biasing member and has a free rotation control surface for holding free rotation operation by said operating handle, said free rotation control surface applying resistance against movement of said operating handle in a return direction with respect to said free rotation operation.