Means for directing flushing fluid into a rock drill at a point intermediate the ends of the striking bar.

Apparatus for excavating hard soils comprising support means, an endless chain capable of movement relative to said support means, drive means for moving said endless chain, means integral with said endless chain operable to contact said hard soils, and means for concentrating the force exerted by said soil contacting means against said hard soils at a specific point along said endless chain while said endless chain is being moved relative to said support means.

A rock bolt assembly incorporating a friction reducing washer of plastics material between the nut and the plate washer to give an increased tension in the bolt for a given torque.

A drilling assembly for use in percussion drilling comprising a drill bit and a drill rod having cooperating conical surfaces, one of said surfaces being provided with a helically extending thread. For purposes of ensuring a reliable connection the thread meets certain geometrical demands and is designed as a left hand thread. Further, the conical surface being provided with the thread is harder than the other conical surface.

A rock drill for percussion drilling comprises frontal and gauge button inserts, said frontal button inserts being parallel with the longitudinal axis of the rock drill and said gauge button inserts being inclined at an angle relative to said longitudinal axis and arranged to define the diameter of the hole drilled by the rock drill. The number of the frontal button inserts is two and the number of gauge button inserts is two.

A rock drill is formed of an axially elongated member made up of a cutting bit at one end followed by a helically grooved shaft and then ending in a shank. At least a portion of the groove, viewed in the axial direction of the member, has a stepped bottom providing groove sections of different depths. The depth of the groove section from the surface of the shaft decreases in the direction toward the shank. The groove sections with stepped bottom commence at a certain axial length from the cuttin...

The rock drilling rig comprises a first control unit (8) arranged on a carrier (1) and a second control unit (9) arranged to a rock drilling apparatus (4). The first control unit (8) and the second control unit (9) communicate with each other by means of a first data communications link (10). The rock drilling apparatus (4) has one or more sensors (11, 12, 15), the measuring results of which are processed in the second control unit (9) and only then transmitted to the first control unit (8) that...

The present invention is related to a rock bolt (7), expandable by means of a pressure media, for insertion into a borehole. The expandable bolt (7) comprises a connection unit (8) with means (11) for detachable interaction with an expansion means (10) for expansion of the rock bolt (7), as well as with a suspension element (16). The connection unit is designed with such external dimensions so that it may be inserted into the bore-hole. The invention also relates to such a rock bolting system.

A rock cavity for storing fluids, solid products for some other purpose, such as the protected manufacture or production of goods, comprising a substantially vertical, cylindrical rock cavity comprising a conical top section (14), and a conical or horizontal bottom section (15) and a vertical section (1) extending therebetween and presenting in cross-section a polygonal shape, wherewith vertical shafts (11) are located in at least half the corners of the polygon.

A rock drill in which the depth of the recessed groove for accommodating the cutting body is made greater than the axial brazing-in depth of the cutting body whereby a largely stress-free seating of the cutting body results. In particular, for rock drills for making break-throughs, this recessed groove extended in the radial direction into lobes of a drill head can be used for locating cutting bodies in the lobes.