Captive fastening element

Claim 1

Captive fastening element apparatus of the type adapted to be inserted into a receptacle such as a hole drilled into a bed of solid material such as concrete or the like and comprising; a shank portion of uniform cylindrical section of predetermined diameter; an outer end portion on one end of said shank adapted to extend outwardly from said bed; engageable means on said outer end whereby a longitudinal force can be applied to said shank tending to draw same out of said bed; a tapered axially extending inner end of generally circular cross-section on the other end of said shank, of reduced diameter adjacent to said shank portion gradually enlarging toward the free end thereof: a single locking band member having two ends, and having a thickness approximately equal to the difference in radius between said shank portion and the thinner region of said generally circular cross-section tapered inner end, formed into a generally cylindrical shape, said two ends of said band defining a slotted opening therealong permitting said band to be expanded, by relative movement of said tapered inner end, into engagement with said bed; outwardly oriented tongue means on said locking band member, said tongue means being resilient, and being adapted to be squeezed against said generally tapered end, while same is being inserted, into said receptacle and being urged into engagement with said bed, whereby to prevent removal therefrom or rotation relative thereto, and at least one generally flattened surface portion formed along at least part of said generally circular cross-section tapered inner end, and a corresponding flattened portion formed on said locking band member, overlying said flattened surface portion of said tapered end, thereby preventing relative rotation between said band member and said tapered end.