Device for testing the holding force of fastener elements secured in a base material

A device for testing the holding force of fastening elements having an axially extending bore therein and secured in a base material, comprises an axially extending load application member (1) having a first end and a second end spaced axially apart and an axially extending impact member (2), said impact member being axially displaceable relative to said load application member (1), said impact member (2) having a first end and a second end spaced axially apart and a central passageway arranged to receive and guide said load application member, said load application member (1) having an axially extending coupling region (3) extending from the first end thereof towards the second end thereto, said coupling region (3) being engageable in the bore of a fastening element to be tested, said load application member (1) having a stop surface (4) thereon spaced between said first and second ends thereof and facing towards said first end thereof, said impact member (2) having a first stop surface (6) facing away from the first end thereof and arranged to interact with said stop surface (4) on said load application member, said coupling region (3) having a substantially cylindrical outside surface, said outside surface of the coupling region (3) having at least one projection (14) extending radially outwardly therefrom, and said projection (14) being elastically deflectable.