Non-rotating stabilizer for drill string

摘要

A stabilizer for attachment to drill string in large diameter earth boring or shaft drilling to center the drill string and maintain alignment of the drill bit. The stabilizer has an inner hub that is rigidly secured to the drill string above the bit. A rubber tube inside the inner hub is compressed to lock the inner hub to the drill string. An outer hub encircles the inner hub. A bearing is mounted between the inner hub and outer hub to allow rotation with respect to each other. The bearing includes a frusto-conical ring in contact with individual pads that are exposed to the drilling fluid. A number of arms extend radially outward from the outer hub to centralize the drill string. The arms are telescopingly received in the outer hub and are pinned together by tie bars at their outer ends to allow them to be quickly removed.