A nail screw, in particular for connecting facade boards or terrace planks made of wood, especially real wood, has a shaft, a conical tip formed at the front end region of the shaft and a head formed at the rear end region of the shaft. A thread has a forward facing insertion flank and a rearward facing grip flank between the conical tip and the head. The thread is a double thread, wherein a grip flank angle () measured between the grip flank and a plane perpendicular to the longitudinal axis of the nail screw is between 25 and 35 degrees, more preferably between 28 and 32 degrees, most preferably 30 degrees. The conical tip has a tip angle () between 80 and 120 degrees, more preferably between 90 and 110 degrees, most preferably of 80, 90 or 100 degrees.

A screw fastener comprising: an elongate shank (3) having a screw thread (9) extending along at least a substantial portion of the shank; a drive section (7) located at one end of the shank for allowing the screw fastener to be rotatably driven into one or more material layers; and a self-drilling or piercing point (5) at an opposing end thereof for forming a bore in said one or more material layers; wherein the drive section is shaped to minimise or avoid the need for countersinking of the formed bore.

The invention relates to a joining element (10, 50, 70, 100, 130) for connection to at least one component layer (34, 62, 84, 112), comprising a head (12, 52) having a head supporting surface (16, 140) for abutment against a component layer and at least one drive feature (14), via which the joining element can be rotated. The joining element further comprises a shaft (17), which ends via a hole forming element (18, 54, 90, 106) in a point (38), wherein the length of the shaft, from the head supporting surface to the point, is shorter than five times the maximum shaft outer diameter (DMax), wherein the shaft has a holding region (H) for connection to the component layer. A removal region having a removal profile (20, 56, 72, 102, 134) extends on the shaft, subsequent to the holding region in the direction of the point (38), and the removal region starts spaced apart from the head supporting surface at a distance of at least once the maximum shaft outer diameter.

A method of reducing the cycle time required for flow-drill screw operations by providing a dimple on a part that is engaged by a flow-drill screw. A tip of the flow-drill screw engages a contact band at a location spaced from the tip of the distal end of the flow-drill screw and base portion of the dimple. Friction between the flow-drill screw tip and dimple creates a heat concentration area and results in displaced material fanning a threaded collar. The flow-drill screw is secured by the threads of the threaded collar.

A double ended dual attached fastener includes a first portion having a stud bolt, a second portion configured to anchor to a panel member, and a flange nut partitioning the first end and the second end. The flange nut includes a flat interior annular surface facing the second portion. The flange nut includes a plurality of radially spaced weld projections extending toward the second portion. The weld projection includes a material that amendable to form a weld joining the flange nut to a panel member through which the second portion is inserted. The second portion defines a fastener selected from a group consisting of a self-tapping friction screw, a self-piercing rivet, and a swage bolt.

The invention relates to a joining element (10, 50, 70, 100, 130) for connection to at least one component layer (34, 62, 84, 112), comprising a head (12, 52) having a head supporting surface (16, 140) for abutment against a component layer and at least one drive feature (14), via which the joining element can be rotated. The joining element further comprises a shaft (17), which ends via a hole forming element (18, 54, 90, 106) in a point (38), wherein the length of the shaft, from the head supporting surface to the point, is shorter than five times the maximum shaft outer diameter (DMax), wherein the shaft has a holding region (H) for connection to the component layer. A removal region having a removal profile (20, 56, 72, 102, 134) extends on the shaft, subsequent to the holding region in the direction of the point (38), and the removal region starts spaced apart from the head supporting surface at a distance of at least once the maximum shaft outer diameter.

The invention relates to a joining element comprising a shaft to be placed into a component; a head provided at a first end of the shaft; and a punching element attached in a losable manner to a second end of the shaft remote from the head.

A screw structure is disclosed herein. It comprises a rod part, an upper thread part on a periphery of an upper portion of the rod part and having plural thread pitches, a lower thread part on a periphery of a lower portion of the rod part for connecting the upper thread part and having an outer diameter less than an outer diameter of the upper thread part, and a plurality of beveling tangent planes on the periphery of the lower portion of the rod part, wherein the upper thread part forms a first lead angle of 5-15 degrees and a second lead angle of 20-30 degrees, and wherein the first and second lead angles of the upper thread part at a starting point in each of the plural thread pitches are opposite to the first and second lead angles of the upper thread part at a 180-degree position.

A joining method is a method of joining a plate set composed by a plurality of stacked plate members including a first plate member and a second plate member by using a tapping screw. When the tapping screw is advanced into the plate set while the tapping screw is rotated in a state of applying a pressure onto the plate set so as to form through-holes in the first plate member and the second plate member, a first pressure applied onto the tapping screw is reduced down to a second pressure at the time when the tapping screw penetrates the first plate member.

A screw includes a head, a rod extending from a lower end of the head and a tapered drilling portion extending from a lowest end of the rod; the rod having a normal thread with a predetermined length; the normal thread extending from a lower end of the head to the tapered drilling portion, but having a predetermined distance from a tip end of the tapered drilling portion; an umbrella thread extending from a lower end of the normal thread to the tip end of the tapered drilling portion; the umbrella thread being formed by an upper thread surface and a lower thread surface. A second angle between the upper thread surface of the normal thread and the lower thread surface of the normal thread becomes larger and larger from the end near the normal thread to an end near the tip end.