Abstract: A drive mechanism for a drill provides both rotational drive and axial feed for a drill of substantial diameter such as those used to drill holes for roof bolts in mine shafts. A plurality of sprockets carry two chains of drive links which interlock around the drill shaft with each drive link having depressions which mate with scroll-like projections on the drill shaft. For axial feed, the sprockets are driven from worm drives in separate housings on each side of the chains, the worm drives being driven from gears in a gearbox which are connected through a differential gearset to a hydraulic motor. A second hydraulic motor also drives through the differential gearset to rotate the drill shaft and the entire drive chain assembly. A large diameter face seal serves as the partition between the chain drive assembly and the gearbox.

Abstract: A needle valve placed in series with the hydraulic drill feed motor, and responsive to fluid flow in the hydrualic system subject to the operation of a pressure relief valve therein, causes the thrust to increase and the feed rate to decrease as the drill enters a difficult drilling material, a proportional flow divider interposed between the pressurized hydraulic fluid source and the hydraulic drill rotation motor and the hydraulic feed motor splits the flow and maintains a fixed proportion between the flows to the two motors to cause the rotational motor to slow down as the feed motor slows down. A pressure compensated flow control valve bypassing the proportional flow divider to the drill rotation motor insures a fixed amount of fluid flow to the rotational motor regardless of the difficulty of material being drilled to maintain a minimal rotational speed of the drill rotation motor.

Abstract: A flexible shaft is formed of a plurality of linked sections which lock together to provide a rigid shaft when turned in a first direction as for drilling and which, when turned in the opposite direction, unlatch, thereby permitting limited relative movement of the sections so that they may follow a curved path for storage. As the sections are rotated in the first direction, certain internal notches of one section and mating external projections of the next section tend to wedge together and then do not always separate easily and readily when the torque on the shaft is reversed.

Abstract: A drill drive mechanism is especially adapted to provide both rotational drive and axial feed for a drill of substantial diameter such as may be used for drilling holes for roof bolts in mine shafts. The drill shaft is made with a helical pattern of scroll-like projections on its surface for removal of cuttings. The drill drive mechanism includes a plurality of sprockets carrying two chains of drive links which are arranged to interlock around the drill shaft with each drive link having depressions which mate with the scroll-like projections. As the chain links move upwardly or downwardly the surfaces of the depressions in the links mate with the scroll projections to move the shaft axially. Tangs on the drive links mate with notch surfaces between scroll projections to provide a means for rotating the shaft. Projections on the drive links mate together at the center to hold the drive links tightly around the drill shaft.

Abstract: A special drive link permits drilling of holes of different diameters with the same drill drive. The drill shaft has a helical pattern of scroll-like projections for removal of cuttings. The drill drive mechanism includes sprockets carrying two chains of drive links which mate with the helical scroll projections to move the drill shaft axially, and projections on the drive links mate together at the center to hold the drive links tightly around the drill shaft. The drill shaft is formed with an elongated axial groove separating the helical projections and defining notch surfaces which mate with projections or tangs extending inwardly from the hollow portion of the drive links where they surround the drill shaft. Rotation of the mechanism results in transferring the rotating force through the sides of the inwardly extending projection of the drive links to the corresponding notch surfaces of the scroll projections.