A wood screw structure comprises a screw head section, a rod section, a first screw thread and a plurality of crushing rib units. The rod section is sequentially integrally formed from the screw head section and comprises a first rod portion connecting the screw head section, a second rod portion, a third rod portion, and a tapered portion extending and tapering outwardly from the third rod portion. The first screw thread is disposed spirally and is protruded on an outer peripheral surface of the tapered portion, the second rod portion and the third rod portion. The crushing rib units are disposed spirally and protruded around the outer peripheral surface of the third rod portion and the tapered portion, and each of the crushing rib units includes a plurality of crushers protrudingly disposed on a rib body. A first discharge gap is formed between the crushers.

A low energy wood screw that may be inserted quickly and using less energy than conventional screws. In various embodiments, the screw may include a countersunk head having a recess for accommodating a driving tool, a tapered neck, a plurality of crown ribs extending over the head and neck, a lubricating coating, main threads with a large thread lead, and lower threads having an asymmetrical profile and extending onto a gimlet point.

A screw fastener particularly adapted to improve retention while minimizing mushrooming in fibrous workpieces. A single-threaded lower portion neighbours the pointed tip of the screw and a dual-threaded upper portion neighbours the screw head. The upper portion has a first upper thread that spirals in an opposite direction to the singular lower thread, and a second upper thread that spirals in a same direction as the singular lower thread. The lower thread includes a plurality of thread turns that share a same major thread diameter while axially spanning multiple areas of the lower portion of the shaft that vary in diameter, including a bulged area, a reduced upper area of lesser shaft diameter than the bulged area at a location between the bulged area and the head, and a downwardly tapered lower area at which the diameter of the shaft narrows from the bulged area toward the pointed tip.

A construction nailing screw is configured to be used in like manner as traditional nails but rotate during driving through threading, providing retention of the construction nailing screw in the construction material(s), and the ability to be removed from the construction material(s) by reverse rotation. The construction nailing screw is characterized by a shank with a head on one longitudinal end, and a tip on another longitudinal end, with external threading that provides minimal friction during installation and mild resistance during removal, and two cutouts extending along the exterior of the shank and through the external threading. The head allows both a manual installation tool and an automatic installation tool to strike the head and drive (install) the nailing screw. The external threading has an upper side with a high pitch relative to the longitudinal axis of the shank, and a lower side with a low pitch relative to the longitudinal axis of the shank.

A quick fastening screw includes a head, a shank with spirally-disposed thread convolutions, and a drilling portion. Each thread convolution has at least three flank sections and at least three arc sections each formed between any two adjacent flank sections. Two ends of each arc section and the flank sections adjacent to the arc section are respectively intersected to thereby form two joints. Between the two joints is formed a curved cutting portion which forms a radian not more than a quarter of a maximum thread radius so that each curved cutting portion becomes sharp to cut quickly, speed up a screwing operation, decrease the friction between the thread convolutions and a workpiece, and reduce the resistance and torque. The non-circular thread convolutions also receive cut debris efficiently and prevent the cracking of the workpiece caused by the undue accumulation of the debris.

A method for forming a stop flange on a self-tapping screw includes locating a shank of a self-tapping screw between two threading dies, fixing one of the two threading dies and moving the other one of the two threading dies to work the shank, the external thread forming section of each of the threading dies performing threading to form an external thread on the shank, inserting the insert and the recessed corner of each of the threading dies into a top of the external thread to form a groove in the shank, and the insert of each of the threading dies gradually squeezing downward an extruded portion that is formed during formation of the groove to form a stop flange on the shank. Thus, the shank is integrally formed with the stop flange, to stop an excessive movement of the external thread.

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 (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 threaded fastener is provided. The threaded fastener includes a shank having a non-threaded portion and a threaded portion. A tip extends from the threaded portion and a head extends from the non-threaded portion. A plurality of wings extend from the shank and are configured to form a passage as the threaded fastener advances. An enlarged portion is configured to seat in the passage formed by the plurality of wings with the threaded fastener in an installed arrangement.

A fastening arrangement including a grommet, which is configured as a substantially cylindrical sleeve with a head part, with a hollow-cylindrical shaft and with a conical tip, and also a fastener and a nut, for example made of plastic, which is fitted on the first threaded portion of the fastener. The fastener has two threaded portions, wherein one threaded portion is configured as a right-hand thread and the other threaded portion is configured as a left-hand thread (or vice versa). Moreover, the invention comprises a mounting method for such a fastening arrangement, in which the setting operation (anchoring of the fastener, adjustment of the sheath) can be managed in one step without changing the driving direction of the setting tool.