摘要 |
A fastening element for fastening to a wall having an opening therethrough which is accessible only on one side of the wall, comprising a cylindrical upsettable shell having a flanged end. A cylindrical inset member having a flanged head is disposed in the shell, where the outside diameter of the head is equal to the outside diameter of the upsetting shell. Between the inset member and the upsetting shell, in an end zone adjacent the head, there is provided a material-closure, The underside of the head abuts against the shell to define a closed-linkage juncture with an adjoining face surface of the shell through direct contact. The inset member is provided with screwthreads to move the head of the inset member towards the flanged end of the shell, whereby the movement of the head upsets the shell which enlarges outwardly to define a ridge or bulge which abuts against a rear side of the wall, the bulge being larger than the opening in the wall.
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