Patent ID: 7028787

Claim:
A kelly bushing, comprising: a base with a tubular channel therethrough from top to bottom, the base having a plurality of base axle slots, a roller support on the base, the roller support with a plurality of roller support axle slots, at least one roller having an axle with a first portion movably positioned in a corresponding roller support axle slot of the roller support so that movement of the axle there moves the at least one roller with respect to the tubular channel, the axle with a second portion movably positioned in a corresponding base axle slots of the base so that movement of the axle therein moves the at least one roller with respect to the tubular channel, a leveling bar at the top of the roller support, the roller support movable vertically by moving the leveling bar, and the base axle slots at an angle to the roller support axle slots so that movement of the leveling bar effects movement of the base axle slots with respect to the roller support thereby moving the at least one roller with respect to the tubular channel into and out of contact with a kelly within the tubular channel.