Plastic drive pin anchor

Claim 1

A one-piece plastic drive-pin combination anchor comprising an anchor portion and a solid drive pin molded integrally with the anchor portion, said anchor portion provided with a head having a central recess therein extending downwardly from the upper end of the head to a bottom spaced slightly above the lower end of the head, but substantially below the upper end of the head, said recess having a cylindrical wall, said anchor portion having A substantially cylindrical shank provided with external longitudinally-spaced teeth, said anchor portion having a first passageway in its upper end which extends downwardly from said bottom and has a cylindrical wall of slightly lesser diameter than the diameter of said recess, a second passageway extending downwardly from the lower end of said first-named passageway and having a conical wall, and a third passageway extending downwardly from said second passageway and having a cylindrical wall of lesser diameter than said first-named passageway, said drive pin having a substantially flat upper end, a cylindrical outer wall of substantially the same diameter as the wall of said first-named passageway, a length substantially equivalent to the combined length of all of said passageways and terminating in a hemispherical lower end portion of a diameter less than the diameter of said cylindrical outer wall thereby defining a shoulder at the point of interconnection of said hemispherical end and said cylindrical outer wall, and a plurality of circumferentially spaced ribs at the lower end of said drive pin and integrally connecting arcuate portions of the hemispherical end portion of the drive pin to said anchor portion, said connection extending completely between said shoulder and the lower portion of said hemispherical end portion with said anchor portion at least in the area adjacent the bottom of said recess but terminating below the top thereof.