DRILLING TOOL FOR MAKING ONE AND DOWEL FOR SHAPED INSERTION INTO A BIG DEPTH WITH A CONICAL EXTENSION

摘要

An anchor bolt is arranged to be secured in a relatively deeply drilled hole having a conical enlargement adjacent the base or inner end of the hole. The anchor bolt is formed of an axially elongated tie rod and an anchor located on the end of the tie rod which is inserted into the base of the drilled hole. The anchor is made up of a number of radially expandable sleeve segments. The anchor also includes a cone element for expanding the sleeve segments radially outwardly into the conical enlargement in the hole. The sleeve segments have an outside radius variable in the axial direction of the segments. The radially outer surface of the segments is substantially smooth for their axial length. At the smaller diameter end of the sleeve, the segments are held together by an annular elastic disc. The radial outer periphery of the disc projects at least partly beyond the diameter of the smaller diameter end of the sleeve and is arranged to have a larger diameter than the smaller diameter end of the conical enlargement in the hole.