A plate member joining structure includes a lower plate that is made of metal, a fitting base portion being formed at an upper surface of the lower plate; an upper plate that is made of metal, that is disposed on the upper surface of the lower plate, and that has a fitting insert portion that is fitted to the fitting base portion so as to form a first gap between a lower surface of the fitting insert portion and a surface of the fitting base portion facing the lower surface of the fitting insert portion; and a screw that, in a state in which the fitting insert portion is fitted to the fitting base portion, is screwed into the fitting insert portion and the fitting base portion, and joins the fitting insert portion and the fitting base portion together in a plate thickness direction.

The present invention relates to a screw element (1) comprising a threaded shaft (2), a screw tip (4) formed on one shaft end and a screw head (5), formed on an opposite shaft end and with force application means (7), and comprising a screw thread (12) extending on the threaded shaft (2) and on the screw tip (4), wherein the screw tip (4) has a front tip section (4a) tapering toward the screw element end, when viewed in the screwing-in direction (Z), and a section (4b) formed on the threaded shaft with a polygonal cross section, when viewed in cross section, whose enveloping circle diameter (d.sub.h) is greater than a core diameter (d.sub.k) of the screw tip (4), and the polygonal cross section has a corner point (15) lying on the enveloping circle of the section (4b), and a front edge surface (9), radially oriented with respect to a longitudinal center axis (X-X), ends in said corner point in the sense of an increased diameter. The screw tip (4) has a first tapering tip section (4a) with a circular cross section and a second, cylindrical tip section (4c) with a circular cross section formed between the first tip section (4a) and the polygonal section (4b), wherein the screw thread (12) is continuously formed without interruption across the first and second tip sections (4a, 4c) of the screw tip (4).

The invention relates to a method and to an apparatus for setting a screw, in particular a flow drilling screw. In accordance with the method, the screw is driven at a first revolution speed and at a first axial feed force during a time-limited first phase to drive the screw through at least one component. In the event that the screw does not penetrate the component during the first phase, the screw is automatically driven at a second revolution speed that is higher than a first rotation speed and/or at a second axial feed force that is greater than a first axial feed force during a second phase subsequent to the first phase.

A screw structure is disclosed herein. It comprises a head; a rod body integrally extended from the head and having a flat shank part and a tapered tip at a terminal of the flat shank part; a first screw thread disposed on the rod body and having a positioning tooth at a terminal thereof, a plurality of cutting units and a plurality of shaving collection spaces; a plurality of second screw threads disposed on the rod body; and a reamer thread disposed at an upper end of the rod body.

A panel fastener is provided that has a head having a first surface and a second surface opposite the first surface; an engagement feature on the first surface of the head, the engagement feature being configured to be engaged by a driving tool; a shank extending from the second surface of the head; a threaded portion extending from the shank, the threaded portion having first and second helical threads arranged in an intertwined manner; the first thread extending farther radially from the central axis than does the second thread; and the shank being located between the head and the threaded portion.

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.

The invention relates to a connecting element (10, 30) for connecting at least two components that are positioned one on top of the other, comprising a shaft (14, 34) and a head (12, 32), which is provided with a drive (38), the shaft (14, 34) being formed from a base material and ending at the exposed shaft end thereof that is opposite the head (12, 32). The invention is characterised in that a tip (16, 40) made of plating material is applied to the exposed shaft end, which plating material is different from the base material.

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 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.