Fastening for fixing heat insulating plate to substructure

摘要

The fastening comprises a plastics disc and conically tapering shaft to take a metal screw. A multi-edge key indent (13) is formed in the disc concentric with the screw axis and at the bottom has a multi- edged stud (14) parallel to the screw axis. The free height of the stud is equal to or smaller than the depth of the indent. Both the indent and stud can be hexagonal. The shaft has a two-step cone with the opening angle of the shaft section at the end smaller than the opening angle of the adjoining shaft section.