Hilti Aktiengesellschaft

Mark Winkler

Guenter Domani

Carsten Peters

Corinna Achleitner

Hideki Shimahara

Matthias Wissling

A method for producing a twist drill has the following steps. A blank is shaped to form a semi-finished product. The semi-finished product is formed from a core, coaxial with the drill axis, having a radius and a number of webs, arranged on the core, having a height. The semi-finished product has a constant cross section along the drill axis. The webs have a first portion which adjoins the core and in which a width of the web remains constant or decreases in the circumferential direction with increasing radial distance from the drill axis. The webs have a second portion which adjoins the first portion and in which the width of the web increases in the circumferential direction with increasing radial distance from the drill axis. The webs of the semi-finished product are shaped into helical segments using a plurality of rolling tools that annularly enclose the semi-finished product and roll on the webs along the drill axis. The rolling tools have teeth that are inclined with respect to the drill axis. A height of the helical segments is less than the height the webs. Helical segments formed from adjacent webs are in contact with one another in a closing fold. The invention also relates to a twist drill.

Twist drill and production method

The twist drill () has a drilling head (), a continuous two-flute, three-flute to six-flute helix () and an insertion end () that are arranged consecutively on a drill axis (). The helix () has a radial outer dimension () that varies periodically two, three to six times per revolution around the drill axis (). The invention also relates to a production method for such a drill.

An anchor bolt for an expansion anchor, and a method of producing the anchor bolt, is disclosed. The anchor bolt has an expansion body which is arranged coaxially with respect to an axis, where a circumferential surface of the expansion body has ribs and grooves in an alternating manner in a circumferential direction. Top surfaces of the ribs diverge from the axis in a direction along the axis. Bottom surfaces of the grooves converge in the direction of the axis.

Growing community of inventors

Hohenems, Austria

Mark Winkler