Anchor hoist

Claim 1

A boat hoist for controlling the take-up and pay out of lines such as anchor chains independently of a power drive mechanism, the hoist comprising: a gear box housing a worm drive including a gear keyed to a shaft having at least one end projecting to the exterior of the housing for rotation of the shaft with the gear, a thrust bearing disposed interiorly of the box between an axial end of the gear facing towards the projecting end of the shaft and a portion of the box for limiting axial shaft movements in a first direction, a sleeve slipped over the projecting shaft end and including a first friction disc rigidly projecting from the sleeve, means for immovably securing the sleeve to the projecting shaft and permitting an axial adjustment of the sleeve position to control the amount of permissible axial movement of the shaft in the other direction, a second friction disc axially spaced from the first disc and keyed to the sleeve for rotation therewith and relative axial movement with respect to the sleeve, a sprocket disposed between the discs and including friction faces for engagement by the discs so that the sprocket is rotated with the shaft and the discs when the discs are axially biased against the sprocket, an axially movable, non-rotatable pressure plate disposed on the side of the second disc opposite the sprocket, the pressure disc including a radially extending arm, means for grasping the arm to prevent rotational movement of the arm about the shaft axis and permitting movements of the arm and the pressure plate in the direction of the axis, low friction means between the second disc and the pressure plate for the transmission of axial forces therebetween, an actuating plate disposed on the side of the pressure plate opposite the second disc and rotatable with respect to the sleeve, at least a portion of the actuating plate having a lesser radial extent than at least a portion of the pressure plate, means for angularly offsetting the actuating plate with respect to the pressure plate, means for limiting the maximum distance between the first friction plate and the actuating plate, face cams defined by the pressure plate and the actuating plate for increasing the axial distance between them to thereby apply axial forces to the friction discs and impair the free rotation of the sprocket with respect to the sleeve and the shaft, a spring housing mounted to the relatively larger pressure plate portion having a longitudinal extent about concentric with the axis of the shaft, an open and a closed end, and exteNding in an axial direction over the relatively smaller portion of the actuating plate, the housing including a slotted opening facing the actuating plate and extending from the open end of the housing towards the other end thereof, radial finger means projecting from a periphery of the actuating plate and disposed adjacent the open housing end when the pressure plate and the actuating plate are in an axial force releasing position, the finger means having a configuration permitting their entrance into the housing through the open end and the slotted opening, a helical compression spring disposed within the housing, having its ends supported by a closed end and the finger means and biasing the actuating plate in a force releasing direction, to prevent accidental frictional engagements between the sprocket and the friction discs due to uncontrolled angular displacements of the actuating plate from frictional forces caused by the rotation of the sleeve.