The invention relates to a drill head for chambering non-cylindrical, rotationally symmetrical holes. This drill head is characterized in that, starting from a diameter of a guide hole, it can cut a very large chamber out of a workpiece. In addition, the drill head has a simple design and is very robust and tight, so that high cutting capacities can be reliably achieved.

There is provided a undercutting boring tool (10) comprising a bar body (11). A lost motion link consists of a spring (26) selectively compressed by a lost motion rod (27) having a lost motion slot (33) spaced from a drive pin (34). An operating rod portion (36) has a trunnion body (37) at its front end having a pin (41) adapted to engage the lost motion slot (33). A tool carrier (42) forms a pair of spaced flat tines (43) and forms a bearing surface (44) in the bight. The upper tine (43) and the bearing surface (44) section are slotted at (45) to allow the passage of a control link (46). Apertures (47) in the tines (43) engage pins (50) on the trunnion body (37). The bar of a generally H-shaped tool assembly (52) comprises a bearing surface (53) running in the bearing surface (44). A crank portion (54) is connected to the control link (46) via crank pin (55). Drive pins (61) and (62) engage the tool assembly (52) with the end face of the bar body (11) providing positive engagement resisting rotational forces in use. The arrangement allows for post-insertion rotation of the tool assembly (52) from an aligned to a transverse (working) position before engagement of the drive pins (61) and (62).

A tool to aid in the installation of a rock bolt assembly in a rock hole which includes a drive shaft having a proximal end, which is adapted to engage with a drilling rig, and a distal end which includes a recess which is adapted to receive a trailing end portion of the rock bolt and which has a first seat against which an axially pre-set component of the rock bolt assembly abuts, a tubular sleeve telescopically engaged with the shaft which has a first end, which is adapted to receive an axially moveable component of the rock bolt assembly and which has a second seat against which the axially moveable component abuts, and a second end, wherein the sleeve is reciprocally moveable relatively to the shaft between a biased forward position in which the axially pre-set component and the axially moveable component are spaced, and a retracted second position in which the axially pre-set component engages or connects to the axially moveable component.

There is provided a undercutting boring tool (10) comprising a bar body (11). A lost motion link consists of a spring (26) selectively compressed by a lost motion rod (27) having a lost motion slot (33) spaced from a drive pin (34). An operating rod portion (36) has a trunnion body (37) at its front end having a pin (41) adapted to engage the lost motion slot (33). A tool carrier (42) forms a pair of spaced flat tines (43) and forms a bearing surface (44) in the bight. The upper tine (43) and the bearing surface (44) section are slotted at (45) to allow the passage of a control link (46). Apertures (47) in the tines (43) engage pins (50) on the trunnion body (37). The bar of a generally H-shaped tool assembly (52) comprises a bearing surface (53) running in the bearing surface (44). A crank portion (54) is connected to the control link (46) via crank pin (55). Drive pins (61) and (62) engage the tool assembly (52) with the end face of the bar body (11) providing positive engagement resisting rotational forces in use. The arrangement allows for post-insertion rotation of the tool assembly (52) from an aligned to a transverse (working) position before engagement of the drive pins (61) and (62).

A tool aiding the installation of a rock bolt assembly in a rock hole includes: a drive shaft having a proximal end to engage with a drilling rig, and a distal end with a recess to receive a trailing end portion of the rock bolt and which has a first seat against which an axially pre-set component of the rock bolt assembly abuts; and a tubular sleeve telescopically engaged with the shaft with a first end for receiving an axially moveable component of the rock bolt assembly and which has a second seat against which the axially moveable component abuts, and a second end. The sleeve is reciprocally moveable relatively to the shaft between a biased forward position in which the axially pre-set component and the axially moveable component are spaced, and a retracted position in which the axially pre-set component engages or connects to the axially moveable component.

The invention relates to a drill head for chambering non-cylindrical, rotationally symmetrical holes. This drill head is characterized in that, starting from a diameter of a guide hole, it can cut a very large chamber out of a workpiece. In addition, the drill head has a simple design and is very robust and tight, so that high cutting capacities can be reliably achieved.

An apparatus for punching an anchor bolt insertion hole is disclosed. The apparatus enables punching work for forming the anchor bolt insertion hole, of which the bottom side is wider than an inlet, on a panel surface for constructing a concrete structure to be performed regardless of the skill of a worker. During operation, the apparatus provides the movement direction of a hammer drill into the vertical direction and the inclination direction so as to enable precise punching work, and doubly arranges springs, which are elastic devices for adjusting the movement range of the hammer drill, so as to uniformly maintain the angle and size for cutting a wall such that a cross-sectional diameter is large at a portion adjacent to the bottom of the anchor bolt insertion hole.

A tool for roughening a borehole surface. The tool includes a coupling portion for clamping the tool in a drilling machine; and a tool head for machining the borehole surface, where the tool head has an outer shell surface on which a cutter protrudes laterally from the shell surface, and where the outer shell surface has a camber along the longitudinal direction of the tool.

The self-undercut anchor with carbide tip is designed to create a drill hole and enlarging the lowermost end of said drill hole by means of a carbide tip or cutting portion. The carbide tip or cutting portion is positioned in such a way so as to not obstruct the setting of the anchor by means of the spreading lamellae. Once said lamellae have been positioned properly and forced downward, the self-undercut anchor is set in place.