A hydraulic hammering device enables an auto-stroke mode and an idle strike prevention mode to coexist with a simple circuit configuration. A first control valve controls advancing and retracting movements of a piston and a second control valve select either the auto-stroke mode and the idle strike prevention mode. To the second control valve, a shared spool is slidably fitted and a mode selection means is disposed. When the mode selection means allows supply of pressurized oil to an auto-stroke setting portion of the shared spool and prohibits discharge of pressurized oil from an idle strike prevention setting portion, the auto-stroke mode is selected. When prohibiting supply of pressurized oil to the auto-stroke setting portion and allowing discharge of pressurized oil from the idle strike prevention setting portion, the idle strike prevention mode is selected.

A hydraulic hammering device enables an auto-stroke mechanism and an idle strike prevention mechanism to coexist with a simple circuit configuration. The device includes a first control valve to control advancing and retracting movements of a piston, an auto-stroke mechanism and an idle strike prevention mechanism, and a second control valve to select either of the auto-stroke mechanism and the idle strike prevention mechanism. To the second control valve, a shared spool is slidably fitted and a mode selection means is disposed. When the mode selection means allows supply of pressurized oil to an auto-stroke setting portion of the shared spool and prohibits discharge of pressurized oil from an idle strike prevention setting portion, the auto-stroke mechanism is selected. When prohibiting supply of pressurized oil to the auto-stroke setting portion and allowing discharge of pressurized oil from the idle strike prevention setting portion, the idle strike prevention mechanism is selected.

A hydraulic rock breaking machine and an apparatus and method for monitoring operation of the same is provided. The apparatus includes at least one pneumatic sensor arranged for monitoring an inner space of the machine and at least one control unit configured to receive and process the pneumatic sensing data.

A heading machine includes first and second rotating cutting heads each having an axis of rotation extending substantially in a longitudinal direction of the machine, a first cutting roller having an axis of rotation extending substantially horizontal and transverse to the longitudinal direction of the machine, and a further cutting device supported on the cutting frame and arranged to cut off the cusps of unmined material left on side wall. The machine further includes a side stabilizer, and can cut a rectangular profile without leaving cusps left on the side wall.

A hydraulic rock breaking machine and an apparatus and method for monitoring operation of the same is provided. The apparatus includes at least one pneumatic sensor arranged for monitoring an inner space of the machine and at least one control unit configured to receive and process the pneumatic sensing data.

A hydraulic hammering device is capable of sufficiently transmitting blow energy to bedrock while further strengthening cushioning action and suppressing damage to equipment. The device includes a pushing piston disposed behind a transmission member and having a smaller propulsive force than that of a main body, a damping piston positioned behind the pushing piston to slide reciprocally forwards and backwards and having a greater propulsive force than that of the main body, a direction-restrictor in a high-pressure circuit between pushing and damping chambers, to which hydraulic fluid is supplied for providing the pistons with propulsive forces, and a fluid supply source. The direction-restrictor restricts an outflow from the chambers side to the fluid supply source side while allowing fluid inflow from the fluid supply source side to the chambers and the pushing chamber sides. A throttle in a drain circuit discharges leaked fluid from a sliding contact location to a tank.

A hydraulic hammering device is capable of sufficiently transmitting blow energy to bedrock while further strengthening cushioning action and suppressing damage to equipment. The device includes a pushing piston disposed behind a transmission member and having a smaller propulsive force than that of a main body, a damping piston positioned behind the pushing piston to slide reciprocally forwards and backwards and having a greater propulsive force than that of the main body, a direction-restrictor in a high-pressure circuit between pushing and damping chambers, to which hydraulic fluid is supplied for providing the pistons with propulsive forces, and a fluid supply source. The direction-restrictor restricts an outflow from the chambers side to the fluid supply source side while allowing fluid inflow from the fluid supply source side to the chambers and the pushing chamber sides. A throttle in a drain circuit discharges leaked fluid from a sliding contact location to a tank.

A cutting head for cutting apparatus suitable for creating tunnels or subterranean roadways and the like. The cutting head includes a rotatable cutting head body and a plurality of cutting units mounted thereon. The cutting units include at least first and second different types of cutting units. The first type of cutting unit has a first rotatable cutter having a first disc body and a first arrangement of buttons for abrading rock. The first buttons are mounted in a radially peripheral portion of the disc body and protrude outwardly therefrom. The second type of cutting unit has a second rotatable cutter having a second disc body and a second arrangement of buttons. The second buttons are mounted in a radially peripheral portion of the disc body and protrude outwardly therefrom. The different types of cutting units differ from one another by at least the arrangements of their buttons.

A heading machine includes first and second rotating cutting heads each having an axis of rotation extending substantially in a longitudinal direction of the machine, a first cutting roller having an axis of rotation extending substantially horizontal and transverse to the longitudinal direction of the machine, and a further cutting device supported on the cutting frame and arranged to cut off the cusps of unmined material left on side wall. The machine further includes a side stabilizer, and can cut a rectangular profile without leaving cusps left on the side wall.

A hydraulic hammering device enables an auto-stroke mechanism and an idle strike prevention mechanism to coexist with a simple circuit configuration. The device includes a first control valve to control advancing and retracting movements of a piston, an auto-stroke mechanism and an idle strike prevention mechanism, and a second control valve to select either of the auto-stroke mechanism and the idle strike prevention mechanism. To the second control valve, a shared spool is slidably fitted and a mode selection means is disposed. When the mode selection means allows supply of pressurized oil to an auto-stroke setting portion of the shared spool and prohibits discharge of pressurized oil from an idle strike prevention setting portion, the auto-stroke mechanism is selected. When prohibiting supply of pressurized oil to the auto-stroke setting portion and allowing discharge of pressurized oil from the idle strike prevention setting portion, the idle strike prevention mechanism is selected.