Abstract: A backside idler pulley includes a first member forming a first side wall of a circumferential groove of the backside idler pulley and a second member, formed separately from the first member, and forming a second side wall, opposite the first side wall, of the circumferential groove of the backside idler pulley. The first member and the second member form first and second floor supports, respectively. The backside idler pulley further includes a continuous layer between the first side wall and the second side wall, the continuous layer being supported by the first and second floor supports while forming a floor of the groove.

Abstract: A multi-sectional percussive drill bit assembly for drilling holes in earth formation primarily used in conjunction with a pneumatic percussive device. The drill bit assembly is comprised of an easily removable bit that is rotationally driven by a lug and pocket structure and axially limited in travel by means of retaining members.

Abstract: A retainer device (10) is provided for retaining a drill bit (12) within a percussive drill assembly casing (2). The retainer device (10) includes a generally annular body (16) having a central axis and an inner circumferential shoulder portion (18) disposable within the casing (2) such that the body axis (17) is substantially collinear with a casing axis (2a). The shoulder (17) is deflectable between a first position (P1), where the shoulder (18) is contactable with the bit head (14) to retain the bit (12) within the retainer body (16), and a second position (P2). The second position (P2) is spaced radially outwardly from the first position such that the bit head (14) is displaceable through the body (16) in a direction along the casing axis (2a). Also, the retainer device (10) includes a spacer (24) that locates the retainer body (16) at a desired axial position within the casing (2) and a centralizer (26) that centers the body (16) about the casing axis (2a).

Abstract: A steerable reamer and method for use in horizontal directional drilling. The reamer includes a carrier frame rotatably coupled to a reaming body, a carrier frame housing slidably coupled to the carrier frame, and an hydraulic cylinder for tilting the carrier frame relative to the carrier frame housing. The reamer may also include sondes for monitoring the position and orientation of the reamer during operation or a laser guidance system for automatically steering the reamer along a pilot bore.

Abstract: A drill bit suited for impact-assisted directional boring in rock includes a bit body having a frontwardly facing, circular main cutting surface having a number of main cutting teeth disposed thereon. A gage cutter extends radially outwardly from the main cutting surface, which gage cutter mounts at least one frontwardly facing gage cutting tooth thereon suitable for cutting in a circle during straight boring and over an angle defined by less than a full rotation of the bit in order to steer the bit. A heel on an outer side surface of the bit body at a position opposite to and behind the gage tooth provides a reaction surface for the gage cutter. The bit body and gage cutter have a nearly circular side profile along a front portion thereof such that a maximum radial clearance between the side profile and a side wall of a hole being drilled is not greater than about 10 percent of the radius of a circle cut by the gage tooth.