Abstract: A hard rock drill barrel has a barrel portion with a downhole hammer drill disposed therein at the barrel's periphery. A pilot portion, in substantial axial alignment with the barrel but having a smaller diameter, extends distally from the barrel for inserting into a pilot shaft of slightly larger diameter than the pilot portion. In operation, the hammer drill excavates a collar around the pilot shaft when the drill barrel is rotated and supplied with pressurized air, thereby excavating a relative large diameter shaft. The drill barrel is hollow and open at its proximal end to receive and collect cuttings flushed into the shaft above the drill barrel. The piloted drill barrel is adjustable to excavate variable diameter shaft portions, enabling the placement of casing within a larger diameter shaft portion. After adjustment of the drill barrel, smaller-diameter shaft excavation proceeds beyond the casing.

Abstract: A cluster drill includes a first plate portion and a second plate portion. The first plate portion extends parallel to the second plate portion and is rigidly affixed to the second plate portion. At least one first and second plate aperture is formed in the first and second plate, respectively. At least one modular retainer unit, to be mounted within the first and second plate apertures, retains a first and second portion of a rock drill apparatus. A cannister affixes the first plate portion relative to the second plate portion. The cannister may be either cylindrical or contain protuberances to accommodate the modular retainer unit. A drill bit lock restricts motion between the a drill bit and the second plate when desired.

Abstract: An underground excavator includes a chamber defined in the forward section of an excavator body for receiving excavated material such as soil, sand, gravel, clay and their mixtures. A rotary cutter is mounted to the forward end of a rotary shaft for penetrating through the chamber for axial rotation and simultaneous rocking in an axial direction. The cutter has a conical cutter face plate having holes for passing the excavated material of a diameter smaller than an opening disposed in the chamber. Any gravel or the like present in the advancing route to the underground excavator and smaller than the holes of the cutter is received into the chamber to be discharged from the excavator. Any gravel larger than the holes or the like not receivable into the chamber is moved quickly along the conical cutter face plate toward peripheral ground layer by being subjected to the rocking motion of the conical cutter face plate simultaneously with the rotation of the cutter during advancement of the excavator.

Abstract: A drill bit for drilling a subterranean bore hole which includes a housing having a cap plate adapted for connection to a drill pipe and a base block axially aligned with and spaced from the cap plate by guide members. A plurality of elongated drill rod impact members are carried by a drill rod holder plate disposed between the cap plate and base block for movement longitudinally of the housing. The free ends of the drill rods extend through guide bores in the base block to define exposed working ends for chipping and crushing the formation upon rotation of the drill bit and the introduction of drilling fluid into the housing in a manner to effect a hammer-like action of the drill rods and progressively move them longitudinally outwardly from the base block as they undergo wear.

Abstract: A method for drilling hard material such as rock by fragmenting the rock by impact in selected spaced-apart areas and simultaneously fragmenting the rock by shear between the selected areas. The invention also covers a drill head with particularly arranged impact hammers for carrying out the method, and a drill unit incorporating the drill head.

Abstract: A down-the-hole rock drill including a drill bit provided at the lower end of a drill rod, which is rotatably driven by an above-the-ground motor. To increase the drilling efficiency and facilitate drilling of large-diameter holes a machine casing is positioned between the drill rod and the drill bit, said casing enclosing a hydraulic pump which is rotatably driven by the drill rod. The hydraulic pump delivers pressurized liquid to and drives the percussion unit including a hammer, the latter delivering blows against the drill bit at regular intervals. The machine casing also encloses at least one hydraulic motor driven by the pressurized liquid and arranged to rotate the drill bit. Hydraulically controllable blocking means prevent the machine casing from rotating relative to the drill hole wall while the drill bit is in operation.

Abstract: An impact mechanism for rock breaking, pile driving and pile extracting, and the like, includes a head assembly (18) with a pair of shank members (24,26) movably mounted thereto and flywheel (76,78) and eccentric crankshaft parts (74) rotated by a motor (84). The crankshaft parts (74) intermittently contact one of the shank members (24,26) to drive it outwardly from the head assembly (18) by transmitting flywheel energy thereto. A biasing and dampening device (110) associated with each shank member (24,26) absorbs rebound energy from the shank member (24,26) and maintains the shank members (24,26) disengaged from the crankshaft parts (74) until it is positively urged thereagainst. The head assembly (18) is movably mounted at the end of an articulated arm (10) for maneuvering it into desired work position.

Abstract: A tunneling machine provided with the plurality of impact type cutting tools adapted to be mounted on a rotatable or oscillatable workhead assembly in such order and number that the work done by each of said tools upon angular movement of the workhead is generally equal. The working heads of the tools are mounted in close fit through a circulator disc shaped shield which prevents rock or like particles from passing beyond the workhead area to the bodies of the impact tools. Movement is imparted to the workhead assembly by a plurality of self propelled mechanisms which, along with the workhead, are concentrically surrounded by an enclosed tubular shroud which extends generally the length of the machine and is affixed to the shield.

Abstract: The disclosure concerns a hydraulically driven impactor in which the operng cycle of a reciprocating piston is determined by the retraction velocity and displacement of the piston itself. Energy is conserved and heat dissipation minimised by the utilization of hydraulic spring accumulators to decelerate the piston. The drive to the piston is switched into a forward direction at such a point in each displacement cycle that the rebound energy of the piston is always re-absorbed into the drive fluid. The impactor operates at optimum acceleration and frequency at all times, whether or not impact occurs, and this feature combined with high energy conservation makes the impactor particularly suitable for use in a full-face tunnelling machine where high power density is required and individual impactors are often constrained to operate without impacting the rock face for considerable periods.

Abstract: A tunneling machine is described which uses an array of impact tools for cutting a deep kerf that defines the wall of the tunnel. The impact tool provides impact blows through drill steels to which drill bits are attached. A substantial portion of the drill steels extend through webs which provide bearing support and alignment for the drill steels and bits on a dynamic basis while the kerf is being cut and the webs also permit the drill steel to bend; thus providing clearance between the impact tool and the wall of the tunnel. The webs also provide control of the sideways motion of the bit, while at the same time, providing for full impact blows to be delivered to the working face.

Abstract: An apparatus for breaking and cutting rock and similar materials is provided with one or more roller cutter constructions, each comprising an annular cutter rotatably mounted in a housing. Impact forces are applied directly to the cutter intermittently with a reciprocable hammer. The cutter mountings are constructed to permit the impact force to drive the cutting edge of the cutter into rock while substantially isolating the cutter mountings from the hammer impact and rock reaction forces.