Abstract: The invention relates to a screw anchoring device adapted to be inserted in a bored hole and of the type having a tubular anchoring member moulded from plastics material and provided with longitudinally -- for example axially or helically -- extending slits or slots. The anchoring member cooperates with a screw in such a manner that the anchoring member may be axially compressed and thereby radially expanded by tightening of the screw. A sleeve or tubular member inserted in one end of the anchoring member cooperates with an internal shoulder abutment within the anchoring member, whereby the anchoring device is made universally applicable so that it may be mounted as well in through holes in panels or plates as in nonthrough holes in solid walls whether these walls are made from more or less pressure resistant materials and whether the diameters of the bored holes correspond more or less to the outer diameter of the anchoring device.

Abstract: A bolt anchor construction for attaching metal plates to the roof of a mine tunnel. An expansion shell having a plurality of spaced metal fingers is telescopically mounted on a bolt. A camming plug is threadably mounted on one end of the bolt and is located within and engaged with the spaced fingers. A series of coined teeth is formed in the outer surface of each finger with the rear of the teeth forming a smooth, flat, tapered surface extending downwardly outwardly with respect to the inner surface of the fingers. The camming plug forces the fingers outwardly upon rotation of the bolt whereupon the teeth bite into the rock surrounding the drilled hole to attach the plates to the mine roof. A pair of spaced longitudinally extending bearing strips is formed on the inner surface of each finger for engagement with the camming plug, and the teeth smooth rear surfaces are located between the bearing strips and are free of projections to prevent bending with the plug.

Abstract: A screw type anchor device for securement into masonry structures. A sharp crested helical thread, preferably with tapering crest diameter, is formed along the shank and helical protuberances forming guide means are spaced along the shank between adjacent convolutions of the helical thread. Notches are formed on the crests of the helical thread along the length of the shank to facilitate embedment of the crests in the walls of a performed bore in the masonry structure.

Abstract: A thread swaging screw of polygonal cross-section having a number of turns on a straight shank portion and at least one sizing turn between the shank portion and the tapered work entering end portion of the screw. The sizing turn inwardly of the pitch radii has the same cross-section and flank angle as the turns on the shank portion and the sizing turn in a region outwardly of the pitch radii has a flank angle slightly less than the flank angle o f the turns in the shank portion and crest radii at the lobes which are greater than the crest radii at the lobes of the shank turn to compensate for the contraction of the dedendum portion of the internal threads swaged in the workpiece.

Abstract: Fastening assembly comprising a base, locking or anchoring element, provided with an upper annular flange, which accepts and engages a removable flexible cap or covering element formed of impermeable elastic material, preferably molded thermoplastic, retained thereon by interference fit. The components when united provide a protective and/or decorative cover for a fastening element that can extend into a sub-stratum, work-piece or material through the base element. The cap and base elements may subsequently be marginally welded together so as to safely house electronic components of telephone or computer systems against unauthorised interference.