Abstract: A method of adjusting backlash in a down hole bearing assembly involves providing in side by side relation on an outer surface of an inner mandrel a circumferential first threaded seat adapted to accommodate a first nut which engages the first threaded seat by rotation in a first rotational direction and becomes disengaged by rotation in a second rotational direction and a circumferential second threaded seat adapted to accommodate a second nut which engages the second threaded seat by rotation in the second rotational direction and becomes disengaged by rotation in the first rotational direction. The first nut is threaded onto the first threaded seat to place the inner mandrel in tension with a first stop and a second stop engaging a thrust bearing. The second nut is coupled to the first nut to resisting any rotational movement of the first nut in the second rotational direction.

Abstract: A rotary cutter assembly constructed in accordance with this method of securing a rotary cutter to a body has a cutter pocket with a first shoulder and a truncated second shoulder. A receptacle extends into the first shoulder. A first retainer retains a first axle end of the rotary cutter and engages the first shoulder to prevent axial movement in a first direction. A projection on the first retainer engages the receptacle to prevent removal of the first retainer radially from the cutter pocket. A second retainer retains a second axle end of the rotary cutter. The second retainer has a step down portion engaging the truncated second shoulder of the cutter pocket to prevent axial movement in a second direction. A locking ring overlies the truncated second shoulder and the step down portion of the second retainer to prevent removal of the second retainer radially from the cutter pocket.

Abstract: A drive line for a down hole mud motor has a plurality of elongate keys extending radially from an exterior surface of a central shaft for the purpose of transmitting torque. A plurality of circumferentially spaced axial keyways are provided in an interior surface of each end housing, which are adapted to receive the keys. Each of the keys has opposed sides, opposed ends and a front face. The front face is radiused both in a first direction between the opposed ends and in a second direction between the opposed sides, thereby accommodating the omni-directional pivotal movement of the shaft relative to the housing. The use of keys for torque transmission increases available contact area, with a corresponding increase in torque load capacity.

Abstract: An apparatus for drilling curved sections of well holes is described which includes a first tubular member having a bulbous first end, a second end, an exterior surface and an interior surface defining an interior bore. A plurality of pockets form a first annular ring in the exterior surface at the bulbous first end of the first tubular member. A second tubular member is provided having a first end, a second end, an exterior surface and an interior surface defining an interior bore. A socket is formed to accommodate the bulbous first end of the first tubular member at the second end of the second tubular member. The first end of the first tubular member extends into the interior bore of the second tubular member until the bulbous first end engages the socket. The bulbous first end of the first tubular member is capable of omnidirectional pivotal movement within the socket.

Abstract: A method of increasing the off bottom load capacity of a bearing assembly having an outer tubular member, an inner tubular member telescopically received within the outer tubular member, and bearings disposed between the inner tubular member and outer tubular member to facilitate relative rotation of the outer tubular member and inner tubular member while bearing radial and axial loads. The method consists of the following described steps. Firstly, form a first shoulder and a second shoulder in opposed spaced relation on an interior surface of the outer tubular member. Secondly, form a first shoulder and a second shoulder in opposed spaced relation on an exterior surface of the inner tubular member. The shoulders on the inner tubular member are generally parallel to the shoulders on the outer tubular member thereby defining a containment chamber. Thirdly, place at least one thrust bearing in the containment chamber. The thrust bearing having a first side race and a second side race.

Abstract: An orientatable adjustable bent housing consisting of a tubular inner housing which is telescopically received within a tubular outer housing. A sleeve is provided which has an angular offset end face. The sleeve is axially slidable along the inner housing between a coupled position wherein spline non-rotatably couple the sleeve with the inner housing and an orientatable position wherein the sleeve is disengaged from the spline permitting respective rotational positioning of the sleeve and the inner housing. In the coupled position the sleeve is further slidable between an inoperative position wherein the sleeve is spaced from the outer housing and an operative position. In the operative position the angularly offset end face of the sleeve is brought in face to face relation with an angularly offset end face of the outer housing thereby creating a bend the magnitude of which is dependent upon the relative rotational positioning of the outer housing and the inner housing.