| 摘要 |
A torquer/thruster with a hydrostatically actuated chuck assembly having an elastomeric bladder that is fitted about a cylindrical collet into which a flexible roof drill is received. The collet is formed with a series of spaced slits that are disposed in helical paths, portions of the collet between the slits drivingly engage the drill shaft when the bladder is urged against the collet. The collet and bladder are mounted for rotational movement within a piston assembly that is constrained for limited longitudinal movement and fixed against rotational movement. The collet and bladder are moved longitudinally by the piston assembly for applying thrust to the roof drill and are rotatably driven by a rotary driver for applying torque to the roof drill. A pair of driven biased members engage the shaft and provide thrust assistance and retraction of the roof drill. |
