A hybrid bit includes an earth-boring element and a percussion element. The earth-boring element and the percussion element are coaxially arranged, with the earth-boring element surrounding the percussion element. A reciprocating member of the percussion element may oscillate in a manner that enables a bottom end of the reciprocating member to repeatedly protrude from a bottom end of the earth-boring element and to be repeatedly withdrawn. A configuration of the earth-boring element may enable it to drill into and remove some materials from an earth formation, while the percussion element may enable the hybrid bit to drill into and remove difficult-to-drill materials, including abrasive materials and/or materials with high compressive forces, such as chert.

An apparatus for boring a wellbore, including a bit body having a first end, an inner cavity, and a second end. The first end is connected to a workstring that is configured to deliver a rotational force to the bit body. The inner cavity contains a profile having a first radial cam surface. The second end includes a working face containing a cutting member. The apparatus also includes a pilot bit rotatively connected within the inner cavity. A second radial cam surface is contained on a first end of the pilot bit. The first and second radial cam surfaces are operatively configured to deliver a hammering force. A second end of the pilot bit may include an engaging surface configured to engage a formation surrounding the wellbore. The bit body rotates relative to the pilot bit.

An apparatus for boring a wellbore, including a bit body having a first end, an inner cavity, and a second end. The first end is connected to a workstring that is configured to deliver a rotational force to the bit body. The inner cavity contains a profile having a first radial cam surface. The second end includes a working face containing a cutting member. The apparatus also includes a pilot bit rotatively connected within the inner cavity. A second radial cam surface is contained on a first end of the pilot bit. The first and second radial cam surfaces are operatively configured to deliver a hammering force. A second end of the pilot bit may include an engaging surface configured to engage a formation surrounding the wellbore. The bit body rotates relative to the pilot bit.

A percussive rock drill bit has a head and a shank in which a plurality of flushing grooves extend radially outward and axially rearward from a front face. The flushing grooves are configured to optimize the axially rearward flow of rock particles and fines entrained in the flushing fluid. In particular, each groove is generally convex relative to a longitudinal axis of the drill bit and is declined continuously relative to the axis from a first groove end to a second groove end.

A percussive rock drill bit has a head and a shank in which a plurality of flushing grooves extend radially outward and axially rearward from a front face. The flushing grooves are configured to optimize the axially rearward flow of rock particles and fines entrained in the flushing fluid. In particular, each groove is generally convex relative to a longitudinal axis of the drill bit and is declined continuously relative to the axis from a first groove end to a second groove end.

The present disclosure describes various embodiments, as well as features and aspects thereof, of an improved drill bit assembly for a percussion boring system. More specifically, one non-limiting embodiment of an improved drill bit assembly for a percussion boring system comprises a bit and a product engagement member. The bit comprises a slant faced head and at least one exhaust port. The product engagement member comprises a product coupling portion and at least one fluid restriction portion. This improved drill bit assembly is such that, when the product engagement member is detachably engaged with the slant faced head of the bit, a first portion of the fluid stream expelled from the bit is directed substantially forward of the slant faced head and a second portion of the fluid stream is directed substantially rearward from the slant faced head.

The present disclosure describes various embodiments, as well as features and aspects thereof, of an improved drill bit assembly for a percussion boring system. More specifically, one non-limiting embodiment of an improved drill bit assembly for a percussion boring system comprises a bit and a product engagement member. The bit comprises a slant faced head and at least one exhaust port. The product engagement member comprises a product coupling portion and at least one fluid restriction portion. This improved drill bit assembly is such that, when the product engagement member is detachably engaged with the slant faced head of the bit, a first portion of the fluid stream expelled from the bit is directed substantially forward of the slant faced head and a second portion of the fluid stream is directed substantially rearward from the slant faced head.

A piloted rock drill bit includes an integral body having a pilot drill section, a reaming section and a mounting base section extending along a longitudinal axis. The reaming section includes four wings extending from the longitudinal axis in an X pattern. A cutting carbide member is secured to each wing. Waste debris ejection slots extend radially into the reaming section between the wings. The pilot drill section includes a post and a leading carbide member. The leading carbide member includes a pair of sloped surfaces extending forwardly towards each other and intersecting at a leading cutting edge. The leading cutting edge and sloped surfaces extend along a crescent shaped arc. Forward air delivery bores extend through the body to forward discharge openings at the pilot drill section. Rear air delivery bores extend through the body to rear discharge opening at the waste debris ejection slots.

A piloted rock drill bit includes an integral body having a pilot drill section, a reaming section and a mounting base section extending along a longitudinal axis. The reaming section includes four wings extending from the longitudinal axis in an X pattern. A cutting carbide member is secured to each wing. Waste debris ejection slots extend radially into the reaming section between the wings. The pilot drill section includes a post and a leading carbide member. The leading carbide member includes a pair of sloped surfaces extending forwardly towards each other and intersecting at a leading cutting edge. The leading cutting edge and sloped surfaces extend along a crescent shaped arc. Forward air delivery bores extend through the body to forward discharge openings at the pilot drill section. Rear air delivery bores extend through the body to rear discharge opening at the waste debris ejection slots.

A hybrid bit includes an earth-boring element and a percussion element. The earth-boring element and the percussion element are coaxially arranged, with the earth-boring element surrounding the percussion element. A reciprocating member of the percussion element may oscillate in a manner that enables a bottom end of the reciprocating member to repeatedly protrude from a bottom end of the earth-boring element and to be repeatedly withdrawn. A configuration of the earth-boring element may enable it to drill into and remove some materials from an earth formation, while the percussion element may enable the hybrid bit to drill into and remove difficult-to-drill materials, including abrasive materials and/or materials with high compressive forces, such as chert.