Abstract: An apparatus includes a feed cylinder having a first end port and a second end port. A feed cylinder is located within the feed cylinder and is movable in a drive direction in response to fluid pressure applied to the first end port, and is movable in a return direction in response to fluid pressure applied to the second end port. A feed pump selectively displaces fluid between the first and the second end ports. A variable overcenter device controls fluid pressure offset, independent of the feed pump, between the first end port and the second end port. An adjustment device automatically adjusts the variable overcenter device during travel of the feed cylinder in the drive direction to a value corresponding to an amount of force required to displace the feed cylinder in the return direction.

Abstract: The invention relates to a rock drilling apparatus comprising a carrier and at least one drill boom mounted in the carrier and provided with a drifter and a feeding beam. Valves for the control of the operations of the drifter and the feeding beam are arranged in the form of an integral control unit. The control unit is mounted in a cradle provided for the feeding beam and it communicates with the carrier by means of merely two pressure fluid hoses and a control cable.

Abstract: A telescoping drill has a base, a guideway displaceable longitudinally forwardly and rearwardly on the base, a guideway actuator braced between the guideway and the base and energizable for longitudinal forward displacement of the guideway on the base, a guideway source of energy connected to the guideway actuator for longitudinally forwardly displacing the guideway on the base, a drill carriage displaceable longitudinally on the guideway between a front position and a rear position, a drill actuator braced between the drill carriage and the guideway for longitudinal forward displacement of the carriage on the guideway, and a drill source of energy independent of the guideway energy source and connected to the drill actuator for longitudinally forwardly displacing the drill carriage on the guideway. A sensor detects when the drill carriage is in the rear position.

Abstract: In a rotary drilling apparatus, a rotary head is advanced against an object to be drilled and a neck element included in the rotary head and connected with drilling member is rotated around its longitudinal axis relative to a rotary head body. The neck element is subjected, in a normal drilling situation to the action of two oppositely-directed forces produced by means of a pressure medium, the first force acting in the drilling direction and the second force acting in the direction opposite to the drilling direction, the first force being greater and the difference between the forces producing a feeding force. The neck element is movable in the direction of the feeding force. In a drilling situation, when the force acting in the direction opposite to the feeding force is greater than the feeding force, the neck element moves in the direction opposite to the drilling direction relative to the rotary head body.

Abstract: An earth boring apparatus for driving a boring tool, the tool having a head for penetrating the earth and a longitudinally extending rotary drive shaft (15) for advancing the head. A carriage (18) is mounted to support frame (10) for advancing movement so as to advance and retract the drive shaft (15) and head. A drive shaft extension can be fitted between the carriage (18) and the drive shaft (15) thereby extending the effective length of the drive shaft (15). The apparatus includes a shaft engaging member (40) associated with the frame (10) and selectively operative to engage the shaft (15) having the head thereon and to inhibit rotation thereof thereby enabling the carriage (18) to be retracted and the drive shaft extension to be fitted between the carriage (18) and the shaft (15).

Abstract: A method of and an arrangement for controlling rock drilling when a feeding beam (3) is displaced so that the forward end thereof makes contact with a rock surface to be drilled. The arrangement comprises a displacing device for displacing the feeding beam in the longitudinal direction thereof and a control device for controlling the operation of the displacing device. The control means comprise a control element which is mounted at the forward end of the feeding beam (3) so that when the feeding beam is displaced in the longitudinal direction, the control element is the first to make contact with the rock surface. The control element is connected to stop the operation of the displacing device of the feeding beam (3) when it hits the rock surface.

Abstract: When drilling deep boreholes with a down-the-hole drill (15), the pressure and the flow of the motive fluid are controlled so that the impact velocity of the piston hammer of the drill is kept within narrow limits independently of the counter pressure in the borehole. For this purpose the quotient of pressure and flow can be held substantially constant.

Abstract: A control system guides a boring tool in a borehole. The tool has a longitudinal tool axis and includes a driver for advancing the tool axially through the earth and steering mechanism for directing the motion of the tool relative to the tool axis in response to control signals. The control system includes an axial electromagnetic source for generating an axial alternating magnetic field directed along an axial source axis. A sensing assembly remote from the source means includes first and second pickup coils for sensing the alternating magnetic field. Each of the first and second pickup coils has a respective coil axis and is rigidly mounted in respect to the other with their respective axes at a substantial angle with respect to each other, defining a sensing assembly axis substantially normal to both coil axes. Each coil generates a respective null electrical signal when the lines of magnetic flux at the respective coil are normal to the respective coil axis.

Abstract: A system for controlling the vertical movement of a drillstring and which is removably interconnected with a conventional drill rig. The system includes at least one fluidic cylinder and piston assembly removably connected at an upper end to a support, such as the rig's traveling block assembly, and at a lower end to the drillstring. A pump is operatively connected to the cylinder and piston assembly and a control valve device is provided to control the flow of the fluid to and from the cylinder and piston assembly. A computing device is in operative communication with a data measurement system and the control valve device and is used to automatically control the movement of the drillstring in response to data, such as WOB, received from the data measurement system.

Abstract: A vibrationless percussion tool is disclosed characterized by use of a piston mounted for reciprocal movement against a constant pressure force within a casing to cyclically impact an anvil disposed adjacent the distal end of the casing. A spool valve is disposed within the interior of the piston and is adapted to travel in unison with the reciprocating piston except during mechanical actuation initiated adjacent the extreme downstroke and upstroke position of the piston within the casing. The constant pressure force is continuously applied to one side of the piston and by mechanical actuation of the spool valve, the volume disposed on the opposite side of the piston is alternatively vented and pressurized to cause reciprocation of the piston against the constant pressure source.

Abstract: A method of excavating a tunnel face in which the cutting head is sunk into the face to form an initial penetration and is then moved laterally. The power consumption of the cutting head drive motor is measured, compared with the setpoint value and the attack increment is controlled accordingly. The arm carrying the cutting head is swung at a maximum swing moment but the swing moment is reduced when monitored distortion of machine parts shows that this distortion has exceeded a predetermined value.

Abstract: A device for disabling the draw works of a well drilling apparatus responsive to the locking of the drill string by a blow out prevention device. The device comprises an air-actuated valve connected for regulating the flow of air to the air-actuated clutch of the draw works. A second valve regulates the flow of pressurized air to the air actuated valve. The second valve is responsive to the actuation of the blow out prevention device by an accumulator valve.

Abstract: A drilled hole end adjusting arrangement for a drilling machine or the like mounted on a boom structure in which the positions of the drilling machine are located such that ends of drilled holes are in a predetermined plane by positioning the boom structure in a rectangular coordinate plane established immediately in front of a working face. The depths to which the holes are drilled are caused to be such that the ends are in a plane parallel to the rectangular coordinate plane by supplying numerical instructions to the boom structure so that the positioning is carried out with high accuracy and the controls for the boom structure can be quickly programmed.

Abstract: A working implement such as a rock drilling apparatus is automatically positioned to predetermined positions and/or directions. Particularly, a drill bit is moved to an imaginary plane spaced from the surface to be worked upon completion of a drill hole by programming the predetermined positions such that they are in said imaginary plane. The actual values of the position and/or direction of the working implement may be adjusted simultaneously toward set values corresponding to the predetermined position and/or direction.

Abstract: A control is disclosed for inhibiting the tilting of an earth drilling machine that is supported on hydraulic jacks. A hydraulic downfeed motor for the drill string is operated by a control that has pressure responsive switches connected to the hydraulic jacks, and in the event the drilling machine starts to rise upwardly during drilling one of the pressure responsive switches will operate to shut off fluid pressure to the downfeed motor and to entrap fluid within the motor. The entrapment of fluid in the motor maintains a drilling pressure that permits drilling to continue with a drilling force that will not allow the machine to rise upwardly on the supporting jacks.

Abstract: A device for mounting a hand operated drill such as a rotary or sinker drill on a backhoe attachment for tractors and trucks including a slide mounted tool carrier attached to a roller chain loop mounted on a mast assembly. The mast assembly is either removably mounted on the bucket of the backhoe attachment or to the bucket linkage.High cycle oscillation is dampened by a shock absorber booster spring assembly.The spring assembly may also be used in combination with a fluid control valve mechanism to automatically adjust the drilling and vance.A trunnion assembly may be provided to increase the positionability of the mounting device.A flow control valve connected to the spring assembly automatically maintains constant thrust values to the drill.

Abstract: A method for drilling boreholes utilizing a plurality of simultaneously operated boring tools. During a drilling operation the loading forces on the tools are measured and constantly compared with a predetermined limiting value representative of a limiting loading value and the variation of a limiting loading value with respect to time. If these limiting values are exceeded at least one working parameter of the tools is adjusted such as feed force, feed speed or track speed of the tools. Apparatus for carrying out the method is also disclosed.

Abstract: An improved, multipurpose oil well rig employing hydraulically actuable components. Two, three, or four or more piston cylinder fluid motors are provided in the rig lift system, powered either by a power unit having high pressure, low volume pumping characteristics for heavy loads and low pressure, high volume pumping characteristics for light loads or by a power unit incorporating a stored energy accumulator. Novel dump/check safety and control valve means are provided in either power unit. All conventional oil well rig mechanisms are eliminated. Specifically, there are no drawworks, drums, gears, chains, sprockets, clutches, travelling blocks, mechanical brakes, transmissions or line spoolers.