The present invention relates to a hydraulic down-the-hole hammer. The hammer comprises an elongate shaft and a piston having a central bore therethrough, the piston slidably mounted for reciprocal movement on the shaft and arranged to impact a percussion bit. Forward and rear drive chambers for the piston are disposed between the piston and the shaft and the forward chamber is separated from the rear chamber by an annular shoulder formed internally of the piston bore. The hammer also comprises a control valve to control reciprocation of the piston, wherein the control valve is arranged within the central bore of the piston. The hammer may be a disposable water hammer in which the piston is an outermost component of the hammer.

The present invention relates to a hydraulic down-the-hole hammer. The hammer comprises an elongate shaft and a piston having a central bore therethrough, the piston slidably mounted for reciprocal movement on the shaft and arranged to impact a percussion bit. Forward and rear drive chambers for the piston are disposed between the piston and the shaft and the forward chamber is separated from the rear chamber by an annular shoulder formed internally of the piston bore. The hammer also comprises a control valve to control reciprocation of the piston, wherein the control valve is arranged within the central bore of the piston. The hammer may be a disposable water hammer in which the piston is an outermost component of the hammer.

A return exhaust assembly (50) for a reverse circulation hammer H comprises return tube (52) having first and second ends and a seat (56) at or near the first end (54). An exhaust sleeve (58) has: a section (60) seated and resiliently supported on the seat (56); and, a portion (62) that extends to and includes an end (64) of the exhaust sleeve (58) distal the section (60). The portion (60) surrounds a length of the return tube (52) with an annular clearance 66 formed between the return tube (52) and the sleeve (58) from a down hole end of the seat (56) to the distal end (64) of the exhaust sleeve (58). This arrangement allows relative movement, and therefore a degree of misalignment between the exhaust sleeve (58) and the return tube.

A return exhaust assembly (50) for a reverse circulation hammer H comprises return tube (52) having first and second ends and a seat (56) at or near the first end (54). An exhaust sleeve (58) has: a section (60) seated and resiliently supported on the seat (56); and, a portion (62) that extends to and includes an end (64) of the exhaust sleeve (58) distal the section (60). The portion (60) surrounds a length of the return tube (52) with an annular clearance 66 formed between the return tube (52) and the sleeve (58) from a down hole end of the seat (56) to the distal end (64) of the exhaust sleeve (58). This arrangement allows relative movement, and therefore a degree of misalignment between the exhaust sleeve (58) and the return tube.

Disclosed is an automatic force adjustment control system for mobile drilling machines and methods for automatically adjusting a force on a down-the-hole drill bit of a drill string of a mobile drilling machine. A method may include: monitoring bit air pressure of the down-the-hole drill bit during an automatic down-the-hole drilling operation; and automatically adjusting a force provided to the drill string based on the monitored bit air pressure so that the bit air pressure approaches a target air pressure value.

A percussion boring device comprising a casing, a guide tube fixed to the casing, and a control bushing axially displaceable on the guide tube. An impact piston of the device is axially displaceable on the control bushing and configured to be actuated in a reciprocating manner within the casing such that in a first switching position the impact piston strikes a front impact surface to actuate the percussion boring device in a first movement direction, and in a second switching position a rear impact surface to actuate the percussion boring device in a second movement direction. A pressure increasing means is provided and configured to generate a pressure for reversing the percussion bore device, wherein the generated pressure is higher than a pressure for moving the impact piston. The guide tube and the control bushing are configured to reverse movement directions of the impact piston.

Systems for drilling or tunneling include an assembly for accelerating a projectile into a region of geologic material. An interaction between the projectile and the geologic material extends a borehole and forms debris. The debris may be reduced in size by moving the debris to a crushing device. The reduced-size debris is then moved toward the surface using fluid movement. Water jets or other types of devices may be used to cut or deform a perimeter of a region of geologic material before the projectile is accelerated to control the shape of the borehole and the manner in which debris is broken from the geologic material.

Systems for drilling or tunneling include an assembly for accelerating a projectile into a region of geologic material. An interaction between the projectile and the geologic material extends a borehole and forms debris. The debris may be reduced in size by moving the debris to a crushing device. The reduced-size debris is then moved toward the surface using fluid movement. Water jets or other types of devices may be used to cut or deform a perimeter of a region of geologic material before the projectile is accelerated to control the shape of the borehole and the manner in which debris is broken from the geologic material.

Embodiments disclosed herein relate to tools capable of amplifying or dampening axial forces produced by downhole equipment. More specifically, apparatus and methodologies provide a tool for imparting amplified axial loads (e.g., a hammer sub), or, in the alternative, for dampening/reducing downhole vibrations or “noise” (e.g., a suppressor sub).

Embodiments disclosed herein relate to tools capable of amplifying or dampening axial forces produced by downhole equipment. More specifically, apparatus and methodologies provide a tool for imparting amplified axial loads (e.g., a hammer sub), or, in the alternative, for dampening/reducing downhole vibrations or “noise” (e.g., a suppressor sub).