Abstract: An impact resistant assembly is provided which comprises a longitudinal, molded shaft composed of a thermoplastic material and having screw threads at one end thereof and a planar head plate at the opposite end. Adjacent to the head plate is an upper cylindrical shaft section upon which is securely positioned a metal collar, which is preferably provided with an enlarged metal rim, to support the head plate and adjacent cylindrical shaft section against substantial deformation during the subsequent molding thereon of a resilient, head member which is formed from a thermosetting material. It has been found that the combination of the planar head plate and the adjacent metal collar is essential to form the desired impact resistant assembly having the resilient, impact resistant head member molded thereon. The impact resistant assemblies of this invention are particularly suited for use in bowling alley backstops which are subjected to repeated and severe direct impacts by bowling balls of high mass.

Abstract: A releasable clasp for a necklace or the like wherein a rigid housing having an open end houses a tubular holder of flexible material with a transverse web having a hole therethrough adjacent the open housing end. Also included is a shaft of rigid material having an enlarged head at one end thereof which is sized so that the shaft head can pass through the hole in the web with the application of a predetermined joining force and can be withdrawn therefrom only upon application of a pre-established withdrawal force. The housing and holder together form a first clasp part, while the shaft constitutes a second clasp part. The shaft may be twisted to detent into a locking position.