A screw includes a head having a top face and a conical bottom surface, a shank, and thread convolutions. A chip guiding channel is recessedly formed on the conical bottom surface. On the conical bottom surface are spirally disposed a cutting portion which has a plurality cutting units sequentially arranged in a spiral manner, thereby allowing the chip guiding channel to be surrounded by the cutting units along a spiral track. The spiral arrangement of the cutting units assists the head in cutting fibers of a workpiece which are wound around the head into small chips in a continuous and spiral severing manner to reduce drilling torque and resistance, and the spirally-defined chip guiding channel also facilitates a smooth removal of the chips, thereby allowing the head to fit level with a top surface of the workpiece and increasing a fastening effect.

A screw with multiple thread angles includes a shank, a main threaded portion having thread convolutions, and a head. Each thread convolution defines different thread angles from a root to a thread crest in sequence, namely a first thread angle ranging between 70 degrees and 75 degrees, a second thread angle ranging between 37 degrees and 43 degrees, and a third thread angle ranging between 20 degrees and 23 degrees. Notches are recessed into the thread crest for attaining a smooth removal of cut chips. The third thread angle assists each thread convolution in cutting a workpiece sharply to facilitate a quick cutting operation. The second thread angle and the first thread angle help widen a cutting track caused by the cutting operation gradually so that the thread convolutions are continuously drilled into the workpiece by a multi-stage reaming and drilling operation to achieve a quick screwing effect.

Various embodiments of a fastener driveable into a substrate are provided. The fastener includes a head, a shank, and a helical thread formation. Portions of the shank and helical thread formations may be tapered. The outer diameter of the shank may decrease in a direction away from the head. An outer diameter of the thread formation may increase in a direction away from the head. The head may include a plurality of extending ribs. The helical thread formation may be formed with a plurality of grooves that are respectively each partially defined by a straight cutting edge. These improvements reduce torsional failure of the fastener from over tightening.

Various embodiments of a fastener driveable into a substrate are provided. The fastener includes a head, a shank, and a helical thread formation. Portions of the shank and helical thread formations may be tapered. The outer diameter of the shank may decrease in a direction away from the head. An outer diameter of the thread formation may increase in a direction away from the head. The head may include a plurality of extending ribs. The helical thread formation may be formed with a plurality of grooves that are respectively each partially defined by a straight cutting edge. These improvements reduce torsional failure of the fastener from over tightening.

A façade comprises a façade panel, a hanger and a fastener extending through the hanger into a blind hole provided at the façade panel. The fastener comprises a shaft defining a fastening direction and has a front face facing in the fastening direction for penetrating the façade panel and a back end facing in a direction opposite to the fastening direction, and a head arranged at the back end and having a bearing surface facing in the fastening direction for bearing on the hanger. The front face has an outer edge at an outer circumference of the shaft and a recess falling short in the fastening direction with respect to the outer edge.

A fastener may include an elongated shank, a head at a distal end of the shank, and a drill point at a terminal end of the shank, which is opposite to the distal end. The fastener may include a primary thread starting at the drill point and extending along the shank towards the head. The fastener may include a secondary thread starting at the drill point, extending along the shank towards the head, and stopping in an axial direction before the primary thread ends. The secondary thread may be radially located 180 degrees from the primary thread. The drill point may include a plurality of radially extending cutting edges and one or more relieved flute portion extending along the surface of the drill point.

A blind rivet-nut having an annular-flange-like setting head and a hollow shaft for securing a blind rivet-nut in an opening of a carrier. The hollow shaft has a free end having a threaded portion for receiving a threaded element of a tensioning tool. A clamping portion adjacent to the setting head forms a bead-like deformation when the tensioning tool is used to clamp the carrier between the bead-like deformation and the setting head. A threadless shaft portion is formed between the clamping portion and the threaded portion. The threadless shaft portion is threaded by a thread self-rolling or thread self-tapping fastener. The fastener is received in a positive-locking manner when the fastener is screwed into the thread formed on the previously threadless shaft portion. A method is also disclosed for securing a component to a carrier by a blind rivet-nut.

A bushing includes an upper collar with a lower sheath and an annular shoulder intermediate the collar and sheath. The collar has a plurality of spaced apart notches and the sheath has a plurality of spaced apart slits that may be circumferentially aligned with the notches. The sheath has a plurality of spaced apart ribs projecting outward circumferentially offset from the slit for assisting in maintaining the sheath within a hole in a fastener with the annular shoulder against the fastener. A securing member with an elongate shank extending from a head with a distal portion is maintained in the longitudinal opening in an upright position aligned with the hole. As the fastener is driven longitudinally through the opening and hole, force from the fastener causes the bushing to break away and yields direct contact between the securing member head against the top surface of the fastener.

The invention relates to a screw (1), having a shank (3) which is provided with a thread (2) with at least one asymmetrical thread turn (4) with a plurality of windings, wherein the thread has an external diameter (Da), a core diameter (Dk) and a thread pitch (P), wherein the thread turn (4) has thread flanks (7, 8) with a flank angle (phi), wherein the thread flanks (7, 8) have a load-bearing flank (7) and a counter-flank (8) which abut one another directly or indirectly in a thread bottom (9) and at a thread tip (10), and wherein a flank angle (phiL) of the load-bearing flank (7) is smaller than a flank angle (phiG) of the counter-flank (8). The flank angle (phiL) of the load-bearing flank is at least 25°, preferably from 25° to 35°, in particular 30°, and the flank angle (phiG) of the counter-flank is at least 40°, preferably from 40° to 60°, in particular 50°, wherein the flank angle (phi) is from at least 65° to at most 95°. Screws of said type are used, in particular, for direct screw connection in light metal cast components.

A wood screw includes a head end, a shank and a tapered end, the head end including a tool engaging part, the head end located at a first end of the shank and the tapered end located at a second end of the shank. A thread is formed along the shank. The head end includes a neck running from the first end of the shank to a head cap, wherein the head cap includes an underside facing the tapered end, wherein the underside includes a plurality of serrations extending around the underside, each serration having a leading face and a trailing face that define a cutting edge, wherein the trailing face of each serration tapers away from the tapered end. A reaming section may be provided between the thread and the head end. The thread may include a notch configuration. The thread may be a dual start thread.