US 5,261,646 AGranted

Winch having automatic brake

AssigneeWarn Industries, Inc.

InventorThomas M. Telford

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Abstract

An automatic brake for vehicle winch that is automatically applied when the applied torque of the drive motor ceases and automatically released upon application of motor torque. The brake features brake pad segments that move radially outward against the interior of the drum to affect braking and retract radially inward to affect releasing of the brake. The pads have tapered ends that mate with opposed frusto-conical shoes. The brake utilizes rotation of a cam rotatable with respect to a cam follower in one direction to force one shoe toward the other to force the pads radially outward to engage the interior surface of the drum. Rotation of the cam with respect to the cam follower in the opposite direction releases the braking action. A wave spring is incorporated to eliminate chatter as the brake is applied and released. The configuration of the brake components provides a conductive path for the dissipation of heat generated by the braking action.

In a winch having a rotatable drum rotatable in both rotative directions, a cable wound onto the drum in one rotative direction and off the drum in a second rotative direction, a drive motor having a drive shaft selectively rotated by the motor in either direction of rotation, and interconnecting mechanism interconnecting the drive shaft and the drum for rotatably driving the drum, said interconnecting mechanism including a gear train that reduces the rotative speed of the drum relative to the motor shaft, and brake mechanism for controlling rotation of the drum comprising:

said drum having a cylindrical inner surface defining an axis,
a plurality of brake pads cooperatively arranged to provide a cylindrical outer braking surface and arranged adjacent the inner surface of the drum, said brake pads having radial movement toward and away from the inner surface of the drum, a brake shoe cooperatively arranged relative to the pads and axially movable into and away from the pads to induce radial expansion and permit radial retraction of the pads,
a cam and cam follower having cooperative cam surfaces that urge axial separation thereof upon relative rotation of the cam and cam follower in a first rotative direction, and permit axial nesting thereof upon relative rotation of the cam and cam follower in a second rotative direction,
a coupling that independently couples the motor shaft to the cam and cam follower, said coupling initially engaging the cam with the motor shaft driven in one rotative direction and initially engaging the cam follower with the motor shaft driven in the other rotative direction to initiate relative rotation of the cam and cam follower in said second relative rotative direction with the motor shaft driven in either rotative direction,
a first biasing member urging rotation of the cam and cam follower in the first rotative direction, and
said brake shoe arranged relative to said cam and cam follower for axial urging of the brake shoe toward the brake pads upon axial separation of the cam and a cam follower.

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Abstract

Claims9