Abstract: A fastener for securing a sheet metal roof panel to a roof frame with a layer of compressible insulation between the two includes an elongated shank with a tip at one end and a driving head at the other. The shank either is inserted tip first through a preformed hole in the sheet or through a hole which the tip drills and the shank is driven through the insulation layer. A first thread on the shank adjacent the tip is driven into the frame and draws a flared portion of the shank through the hole to enlarge the latter and roll over the metal around the edge of the hole. The rolled over edge then is engaged by a second thread on an enlarged portion of the shank under the head and the plate together with a washer are compressed between the second thread and the head so as to prevent overdrive of the fastener and reduce the possibility of the sheet being dimpled. Longitudinally extending beads or a third thread on the flared portion produce a smooth and gradual rolling over of the edge of the hole in the plate.

Abstract: A collar stud assembly for attachment to a plastic boss having a bore therein comprises a double-ended fastener and a sheet metal cap. The double-ended fastener has a shank with a first thread suitable for threading into plastic on one end thereof, a second thread adapted to threadingly engage a nut or other threaded member on the other end thereof and a collar integral with the shank between the first and second thread for limiting the threading movement of the fastener into the bore of a plastic boss. The shank extends beyond the first thread and includes a raised ring at the end of the first thread for holding the metal cap in position for seating on a plastic boss and a knurl which is spaced from the end of the first thread and which provides a shoulder upon which the metal cap rests. The metal cap is adapted to fit over the end of a plastic boss and the top of the cap is captivated on the land of the shank between the knurl and raised ring.

Abstract: A screw includes a metal portion having a threaded shank adapted to be threaded into a workpiece, a head and an annular flange between the head and the shank. The surface of the metal head and the upper surface of the metal flange are irregular so that, when a plastic portion is molded around the head and flange of the metal portion, the metal and plastic portions are relatively fixed to each other. The plastic portion includes a thin skirt which extends around the periphery of the flange and further includes a thin radially extending section which mates with an annular rib extending around the periphery of the underside of the flange to reduce the possibility of failure of the plastic portion as that portion is forced against a workpiece. The section of the plastic portion extending radially under the flange is formed with depending rings which deform and form a seal as the fastener is threaded down to bring the radially extending section toward engagement with the workpiece.

Abstract: A joint structure for use in securing an article to the edge of a piece of composition board includes a screw having an elongated shank with an enlarged head integrally formed with one end thereof and a threaded section formed on the opposite end portion. First and second helical threads in the threaded section having different major diameters are used to secure the fastener within a pre-drilled hole formed in the edge of the particle board. The hole includes an outer end portion whose diameter is greater than the major diameter of the larger thread and whose length is approximately equal to the length of the threaded section of the shank. In addition, the hole includes an inner end portion which opens into and is coaxial with the outer end portion and which has a diameter smaller than the major diameter of the smaller thread. The length of the hole is longer than the length of the shank of the screw.

Abstract: A fastener assembly for use in securing one member to another includes a bolt and a washer telescoped onto the bolt. The washer is formed with a central protruding section and an integral annular flange extending radially outward from the base of the protruding section. A frustoconical recess formed within the underside of the washer is smaller in diameter than the diameter of the protruding section. Mating ratchet teeth formed on the underside of the bolt head and the protruding section interfit so as to enable the bolt to be turned relative to the washer during tightening while keeping the bolt from turning in a loosening direction once the bolt is tightened down. To keep the washer from turning relative to the members secured together by the bolt, angularly spaced sets of two locking teeth are formed within the flange and extend axially therefrom to embed in the upper surface of the top member.

Abstract: A self-drilling fastener includes a shank having a drill tip integrally formed on one end thereof and a head on the other end. The drill tip is defined by two concave grooves formed one on each side of the shank and intersecting with two planar heels formed on the end of the shank to define two cutting edges. Each of the cutting edges is formed with a positive rake angle along the entire length thereof with the rake angle increasing in magnitude upon progressing outwardly along the cutting edge and toward the periphery of the shank. The axes of the grooves are straight and form an acute included angle bisected by the axis of the shank. The heels also intersect at an angle bisected by the axis of the screw, the edge of intersection of the heels defining a chisel edge at the tip of the shank.