A downhole apparatus connected to a workstring within a wellbore. The workstring is connected to a bit member. The apparatus includes a mandrel operatively connected to a downhole motor mechanism, an anvil member operatively formed on the bit member, the anvil member being operatively connected to the mandrel, a radial bearing housing unit operatively connected to the workstring, with the radial bearing housing unit being disposed about the mandrel, and a hammer member slidably attached to the radial bearing housing unit.

A percussion device that includes: an input side; an output side; at least one drive transmitter; a drive transmitter pathway; a percussion impactor; and a percussion anvil; where: the drive transmitter pathway is a circumferential pathway around a longitudinal axis of the percussion device; the drive transmitter pathway includes at least one tooth section including a lift section and a lead section; the at least one tooth section is essentially one wavelength of a sawtooth wave; the lift section is inclined away from a base of the drive transmitter pathway; the lead section is a section of the tooth section which abruptly returns to the base of the drive transmitter pathway; the input side is rotationally isolated from the percussion impactor; the percussion anvil is attached to, or forms part of, the output side; the percussion impactor includes an impact end and a force input end which are longitudinally opposite terminal ends of the percussion impactor; and the impact end faces the percussion anvil; such that: when in use, and the output section is free to rotate, the at least one drive transmitter and the drive transmitter pathway are configured to act co? operatively to transfer the rotational motion of the input side to the output side; and when in use and limited or no rotation of the output side is possible, the at least one drive transmitter and the drive transmitter pathway are configured to act co-operatively to increase, maintain or decrease the distance between the percussion impactor and the percussion anvil; wherein the at least one drive transmitter and the drive transmitter pathway are configured to act co-operatively to accept rotational motion from the input side and transmit a percussive and/or rotational motion to the output side.

A percussion device that includes: an input side; an output side; at least one drive transmitter; a drive transmitter pathway; a percussion impactor; and a percussion anvil; where: the drive transmitter pathway is a circumferential pathway around a longitudinal axis of the percussion device; the drive transmitter pathway includes at least one tooth section including a lift section and a lead section; the at least one tooth section is essentially one wavelength of a sawtooth wave; the lift section is inclined away from a base of the drive transmitter pathway; the lead section is a section of the tooth section which abruptly returns to the base of the drive transmitter pathway; the input side is rotationally isolated from the percussion impactor; the percussion anvil is attached to, or forms part of, the output side; the percussion impactor includes an impact end and a force input end which are longitudinally opposite terminal ends of the percussion impactor; and the impact end faces the percussion anvil; such that: when in use, and the output section is free to rotate, the at least one drive transmitter and the drive transmitter pathway are configured to act co? operatively to transfer the rotational motion of the input side to the output side; and when in use and limited or no rotation of the output side is possible, the at least one drive transmitter and the drive transmitter pathway are configured to act co-operatively to increase, maintain or decrease the distance between the percussion impactor and the percussion anvil; wherein the at least one drive transmitter and the drive transmitter pathway are configured to act co-operatively to accept rotational motion from the input side and transmit a percussive and/or rotational motion to the output side.

A downhole motor (107) which comprises a stator housing (108), a rotor assembly (106) rotatable relative to said stator housing, and an arrangement for enabling, in use, a drill bit connected to the rotor assembly of said downhole motor to be rotated by rotating a drill string connected to said stator housing, wherein said arrangement comprises a unidirectional clutch (117) disposed between said rotor assembly and said stator housing and having at least one pawl which can be displaced between an inoperative position adjacent said stator housing and an operative position in which rotation of said stator housing by said drill string in one sense is transmitted to said rotor assembly via said at least one pawl, means biasing said at least one pawl towards said operative position, means retaining said at least one pawl in its inoperative position, and means which, when sufficient pulling force is applied to said drill string, will cause said means retaining said at least one pawl to release said at least one pawl and enable said at least one pawl to move into its operative position.

A downhole motor (107) which comprises a stator housing (108), a rotor assembly (106) rotatable relative to said stator housing, and an arrangement for enabling, in use, a drill bit connected to the rotor assembly of said downhole motor to be rotated by rotating a drill string connected to said stator housing, wherein said arrangement comprises a unidirectional clutch (117) disposed between said rotor assembly and said stator housing and having at least one pawl which can be displaced between an inoperative position adjacent said stator housing and an operative position in which rotation of said stator housing by said drill string in one sense is transmitted to said rotor assembly via said at least one pawl, means biasing said at least one pawl towards said operative position, means retaining said at least one pawl in its inoperative position, and means which, when sufficient pulling force is applied to said drill string, will cause said means retaining said at least one pawl to release said at least one pawl and enable said at least one pawl to move into its operative position.

An apparatus including a rotating segment having a first radial surface, a non-rotating segment having a second radial surface, a housing disposed around the first and second radial surfaces, and one or more rolling elements disposed between and in contact with the first and second radial surfaces for transferring the non-rotating segment in an axial direction upon rotation of the rotating segment. The non-rotating element may be a second rotating element that rotates at a different rotational rate than the rotating element. Each rolling element moves 360 degrees along a circular path relative to the first radial surface and the second radial surface. The first or second radial surface has a tapered section. A downhole apparatus includes a power mandrel having a first end connected to a power section member and a second end having a rotating cam surface; a rotating element engaging the rotating cam surface; an anvil sub attached to a workstring, with the anvil sub having a stationary cam surface configured to engage with the rotating cam surface. Rotation of the rotating cam surface moves the anvil sub and the workstring axially within the wellbore.

An apparatus including a rotating segment having a first radial surface, a non-rotating segment having a second radial surface, a housing disposed around the first and second radial surfaces, and one or more rolling elements disposed between and in contact with the first and second radial surfaces for transferring the non-rotating segment in an axial direction upon rotation of the rotating segment. The non-rotating element may be a second rotating element that rotates at a different rotational rate than the rotating element. Each rolling element moves 360 degrees along a circular path relative to the first radial surface and the second radial surface. The first or second radial surface has a tapered section. A downhole apparatus includes a power mandrel having a first end connected to a power section member and a second end having a rotating cam surface; a rotating element engaging the rotating cam surface; an anvil sub attached to a workstring, with the anvil sub having a stationary cam surface configured to engage with the rotating cam surface. Rotation of the rotating cam surface moves the anvil sub and the workstring axially within the wellbore.

A tapered magnetorheological (MR) valve includes a first fixed housing that remains in a fixed position along a central axis of the tapered MR valve. A second housing moves linearly along the central axis of the tapered MR valve. The first fixed housing and the second housing together define a first MR fluid chamber and a second MR fluid chamber for containing MR fluid interconnected by an MR fluid channel. The second housing moves linearly between a first position and a second position along the central axis of the tapered MR valve to control flow of the MR fluid through the MR fluid channel.

A tapered magnetorheological (MR) valve includes a first fixed housing that remains in a fixed position along a central axis of the tapered MR valve. A second housing moves linearly along the central axis of the tapered MR valve. The first fixed housing and the second housing together define a first MR fluid chamber and a second MR fluid chamber for containing MR fluid interconnected by an MR fluid channel. The second housing moves linearly between a first position and a second position along the central axis of the tapered MR valve to control flow of the MR fluid through the MR fluid channel.

A downhole apparatus connected to a workstring within a wellbore. The workstring is connected to a bit member. The apparatus includes a mandrel operatively connected to a downhole motor mechanism, an anvil member operatively formed on the bit member, the anvil member being operatively connected to the mandrel, a radial bearing housing unit operatively connected to the workstring, with the radial bearing housing unit being disposed about the mandrel, and a hammer member slidably attached to the radial bearing housing unit.