Hilti Aktiengesellschaft

Oliver Berchtold

Walter Odoni

Alfred Tobler

Wilhelm Gerber

A drilling and chiseling tool bit includes a tool bit head, an axially extending shank and an insertion end for insertion into a drilling or chiseling device. The shank extends between the tool bit head and the insertion end and is divided into individual axially aligned members. The individual shank members are held together by a retaining member which also interconnects the tool bit head and the insertion end. The tool bit head and insertion end are rotatable as a unit and are movable axially relative to one another. By dividing the shank axially, its individual members have a higher natural frequency and afford improved transmission of impact energy. As a result, preventing the excitation of natural vibrations in individual shank members, the vibration period is shorter compared to the impact transmission time period. Accordingly, the sound radiation from the tool bit is reduced.

Drilling and chiseling tool bit

An anchor rod assembly includes an axially elongated anchor rod to be secured in a borehole by a hardenable mass inserted into the borehole around the anchor rod. The anchor rod is divided by slots into a plurality of circumferentially spaced axially extending segments extending from the leading end of the anchor rod. The anchor rod has an axially extending central bore located radially inwardly of the segments. A filler piece is inserted into the central bore and the slots between the segments. The filler piece closes off the slots between the segments at the outer circumferential surface of the anchor rod. Due to the filler piece, the hardenable mass cannot flow into the slots between the segments and the central bore. As a result, the segments follow movement of the borehole wall during any widening of the borehole because of cracked development, and the anchor rod is retained in the borehole. A radially inwardly formed constriction in the outer circumferential surface of the segments adjacent the trailing end of the anchor rod improves deformability of the segments.

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Zollikon, Switzerland

Oliver Berchtold