Abstract: 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.

Abstract: A non-rotational drill bit for a down-the-hole drill hammer is provided that includes a head and a shank extending from the head. The head includes a plurality of axisymmetric cutting members about its working face. The drill bit also includes a porting system that includes a central through hole, an air inlet port, an exhaust outlet port and a central exhaust port for exhausting air from an interior of the drill hammer and for clearing drilling debris from the face of the drill bit.

Abstract: An apparatus for drilling a hole in the ground has a hammer drill installed at a bottom of a rod assembled in multi-stages at support structure on the ground. The hammer drill has a pilot hammer drill and a reamer hammer drill coupled to each other through a key structure formed in the vertical direction so as to allow simultaneous rotations and up-and-down movements relative to each other.

Abstract: In one aspect of the present invention, a drill bit assembly for downhole drilling comprises an outer bit comprising a central axis and an outer cutting area and an inner bit disposed within the outer bit and comprising an inner cutting area. The outer bit comprises a first plurality of cutting elements and the inner bit comprises a second plurality of cutting elements wherein an average distance of each cutting element in the first plurality to the central axis forms a first moment arm and an average distance of each cutting element in the second plurality to the central axis forms a second moment arm. A ratio of the inner cutting area to the outer cutting area is substantially equal to a ratio of the outer moment arm to the inner moment arm.

Abstract: The invention relates to a boring head for a ground-boring device displacing earth with a percussive action, comprising at least three boring head sections, of which the first section has a form optimized for the loosening and for guiding the device, the second section is optimized with regard to the radial displacement of the earth with low resistance to motion, and the third section has a fixed connection to the housing of the ground-boring device. Improved transmission of the advancing forces to the earth and consequently an improved advance of the ground-boring device can be achieved by at least two of the boring head sections being designed so as to be axially movable relative to one another in the longitudinal direction.

Abstract: The invention relates to a method for horizontal drilling with a percussion implement and a percussion head or percussion head element mounted in a movable manner relative to the percussion implement, the percussion impulse being transmitted in at least three steps.

Abstract: The device comprises a solid drill bit (28) and an annular drill bit (40). Axial impacts are exerted on the solid drill bit (28) which are transmitted onto the annular drill bit (40) through impact transmission surfaces. The annular drill bit (40) is freely axially displaceable within limits. It has rearwardly projecting tongues (43) that engage windows (15) of an outer pipe end piece (12). Thus, the movability of the annular drill bit (40) is ensured without any keyings or the like being necessary, which entail the risk of a clogging with bore material. All movable parts are included in the scavenging so that jamming is avoided.

Abstract: A fluid-operated self-propelled subsoil penetrating tool of the type including an elongated housing member having a penetrating nose portion capable of ejecting a jet of liquid under high pressure to break up and disrupt the subsoil adjacent such nose portion followed by a two-component hammering of such soil to displace and compact same as the tool advances. Remotely-operated steering mechanisms control the path of the tool while remotely-read instruments denote the position, depth, direction and attitude of the tool. A trailing umbilical cord provides all motive and operational fluids and electrical power while transmitting instructions and data between the tool and the remote control station. A unique internal structure reduces the rotation of the tool as it advances and provides for the reverse movement of the tool and electrical supplies through the bore created by the movement of the tool through the subsoil.

Abstract: An impact tool having an air-operated hammer for impacting against an anvil in the body of the tool to cause the tool to tunnel through the ground and having passages and conduits opening to the front tip of the tool to pass water to lubricate the tool to ease the passage of the tool through the soil during the propulsion of the tool, the front tip further having a headpiece through which the passages open to the tool exterior surface.

Abstract: Device and method for breaking open the solidified crust of electrolyte on an electrolytic cell, in particular a cell for producing aluminum. At least one projection is provided on the lower part of the shaft of a chisel used on a crust breaker. After breaking through the crust, the chisel is lowered further at least until the lowest projection or projections reaches the lower half of the crust.

Abstract: A hole-driving tool having an air-operated hammer for impacting against an anvil in the body of the tool to cause the tool to tunnel through the ground, wherein the direction of travel is controlled by providing a variable mass distribution over the hammer and anvil combination, and controlling the relative impact position of the hammer against the anvil.

Abstract: A pneumatic percussion boring device, which is particularly intended for boring tunnel-like holes in the ground, comprises a percussion boring tool which is mounted in a tubular housing, a percussion piston which, in operation, reciprocates in the housing and acts on the tool, and a displacement piece which is mounted on the boring tool for laterally displacing the soil through which the boring is being made. The displacement piece tapers in the direction of boring and is formed around its periphery with a series of annular cutting edges. The displacement piece is preferably stepped with each step being of an increasing diameter in a rearward direction with one of the cutting edges extending around the outer periphery of each step. The forwardly directed face of each step may be undercut with a concave annular depression which increases the sharpness of the cutting edge at the outside of the step.

Abstract: An improved earth boring apparatus for soft, hard, and heterogenous formations utilizes a pneumatic hammer combined with an earth boring auger. The pneumatic hammer is supported inside a hollow case of the auger and has a small pilot bit and a large rigid bit plate having the same diameter as the auger flighting. All torque to the apparatus is supplied to the auger case which drives the flighting and the pneumatic bit plate without applying any torque to the pneumatic hammer case. This arrangement utilizes the pneumatic hammer to break up hard material and the auger to remove the cuttings or to cut through soft material. The drive arrangement allows for disassembly of the pilot bit and bit plate without removing the pneumatic hammer.

Abstract: A drill for rock comprising a boring head arranged on one end of a drill shank and having radially projecting wings, an axial centering projection which projects in a boring direction in front of the wings, said wings and said projection constituting carriers of eccentrically arranged cutter bodies and a centering cutter body, respectively. Breaker surfaces are formed on the wing surfaces between the cutter bodies, respectively, pointing to the centering point of the centering cutter body. Each surface of the boring head located between the wings has at least one jacket line which extends longitudinally to the axis of the boring head and directly joins to a jacket line of the outer surface of the centering projection and is inclined relative thereto at an obtuse angle.

Abstract: Disclosed herein is a rotary-percussion earth boring bit that has an improved geometric configuration to extend cutting insert life and reduce cutting insert breakage. The bottom surface contains a flat transverse face with a bevelled edge. Two rows of circumferentially spaced cutting inserts protrude from the bevel. One of the rows is spaced inwardly from an outer row to define an inner row, which has inserts positioned between the circumferentially spaced inserts of the outer row. The longitudinal axes of these inserts are substantially perpendicular to the bevel and inclined outward at an acute angle to the axis of rotation of the bit. A generally longitudinally extending groove is formed between each two adjacent inserts of the outer row. This arrangement produces a symmetry that tends to minimize the number of reflective surfaces. This equalizes the stresses generated by the impact induced shock waves transmitted through the bit.