A friction bolt (10) includes a first generally circular tube (12) having an internal diameter and defining a longitudinal split, the tube being radially expandable. The bolt has a first leading end (16) for insertion into a borehole (50), a second end defining a head (18), and a second generally circular tube defining a longitudinal split and having an external diameter which is substantially the same as or larger than the internal diameter of the first generally circular tube. The second tube is located inside the first tube (12) with an exterior of the second tube in contact with the interior of the first tube (12). The friction bolt (10) is installed in a rock face (80) using standard friction bolt (10) installation equipment and methods.

A friction bolt including an elongated metal tube and a plurality of friction members. The metal tube includes interior and exterior surfaces, a tapered distal end portion, a proximal end portion, and a slit extending along a length of the elongated metal tube. The plurality of friction members extend outward from the exterior surface, and at least some of the friction members have an exposed planar portion to frictionally engage an inner surface of a bore within which the friction bolt is inserted.

The present invention relates to a method for installation of a rock bolt (124) in a first drill hole by means of a rock bolting rig (100), wherein said rock bolting rig (100) comprises a carrier (101), a boom unit (102) fastened to said carrier (101), and a bolt unit (103) fastened to said boom unit (102) via first joint means (106), wherein said bolt unit (103) comprises a feeder unit (104) including means for displaceable carrying of a drilling machine (105), wherein said bolt unit comprises a first (103A) end and holding means (123, 125) for holding said rock bolt (124). The method comprises: by means of said first joint means (106) maneuver said first end (103A) of said bolt unit (103) to a first position for loading of a bolt, when said bolt unit (103) has been maneuvered to said first position for loading of a bolt, providing a rock bolt (124) to said bolt unit (103), for being held by means of said holding means (123, 125), and when said bolt unit (103) has been loaded with said rock bolt (124), maneuver said bolt unit (103) to a position for installation of said rock bolt (124) and loaded with said rock bolt (124) drilling said first hole and installing said rock bolt (124) in said first hole. The invention also relates to a rock bolting rig.

A friction bolt for frictionally engaging the internal surface of a bore includes a circular tube, which is split longitudinally, and which has a leading end and trailing end. An expander mechanism is disposed within the tube towards the leading end. An elongate bar/cable is disposed within the tube and extends between the expander mechanism at one end and an anchor arrangement at the other end. The bar/cable extends through a ring attached to the trailing end into connection with the anchor arrangement. A restrainer member is disposed within the tube adjacent the ring and extends at least partially about and in engagement with the bar/cable. The tube has a weakened region adjacent the ring and the restrainer member extends longitudinally within the tube past the weakened region. The restrainer member includes a projection that projects through the longitudinal split of the tube for engagement with the bore.

The invention provides an end anchored rock bolt 20 which includes an elongate cylindrical body 12 which longitudinally extends between a proximal end and a distal end and a plug 18 at the distal end, which plug is diametrically larger than the cylindrical body 12, is at least partially tapered, tapering towards the proximal end, and is integrally formed on the body 12.

A friction bolt for frictionally engaging the internal surface of a bore includes a circular tube, which is split longitudinally, and which has a leading end and trailing end. An expander mechanism is disposed within the tube towards the leading end. An elongate bar/cable is disposed within the tube and extends between the expander mechanism at one end and an anchor arrangement at the other end. The bar/cable extends through a ring attached to the trailing end into connection with the anchor arrangement. A restrainer member is disposed within the tube adjacent the ring and extends at least partially about and in engagement with the bar/cable. The tube has a weakened region adjacent the ring and the restrainer member extends longitudinally within the tube past the weakened region. The restrainer member includes a projection that projects through the longitudinal split of the tube for engagement with the bore.

Embodiments of the present invention include hot-rolled threaded rebar bolts that have a substantially circular core with semi-continuous threads on opposing sides of the rebar bolts. In some embodiments of the invention the shaft is substantially void of longitudinal ribs along at least a portion of the longitudinal area between the first set of threads and the second set of threads of the shaft. The threaded rebar bolt is manufactured in a continuous hot-rolling process to create a threaded rebar shaft with semi-continuous threads and substantially no longitudinal ribs in the longitudinal areas and no additional machining is required to create the threads after the threaded shaft is created from the hot-rolling process.

A friction bolt includes a first tube having an internal diameter and defining a longitudinal split, the tube being radially expandable. The bolt has a first leading or distal end for insertion into a bore and a second or proximal end defining a head and further includes a second tube defining a longitudinal split and having an external diameter which is substantially the same as or larger than the internal diameter of the first tube. The second tube is located inside the first tube with its exterior in contact with the interior of the first tube. The bolt includes a slip and lock mechanism that allows the first or exterior and second or interior tubes to move relative to each other along the longitudinal axis of the friction bolt when a tensile force is applied to the bolt, but to lock together after the force is removed.

A rock bolt installation for a hole formed in a rock strata includes a cable bolt and a friction bolt disposed within the hole. The cable bolt can be embedded in grout, cement or resin. The cable bolt extends further into the hole than the friction bolt. The cable bolt and the friction bolt are disposed in an overlapping relationship within the hole and are connected structurally in the overlap to each other and to the internal wall of the hole.

A rock bolt includes a wedge-based expansion mechanism. The expansion mechanism includes a drive wedge arranged to expand an intermediate wedge upon tensioning of the rock bolt, wherein the intermediate wedge is arranged to expand a wedge device attached to an outer tube of the rock bolt. The use of the intermediate wedge enables greater expansion of the rock bolt.