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.

The invention is directed to a toolless screw including a body portion which comprises a shaft portion and a screw portion which includes a shank portion and a tip portion. The shank portion includes at least two helical threads which extend off the shank either at different angles, different distances, or a combination thereof. The tip portion is positioned at an end of the shank portion and has a diameter which is less than the diameter of the shank portion and extends to a point. The body portion is integrated with a screw portion at the end of the shank portion which is opposite the end where the tip portion is positioned.

A vehicle component joining method includes, among other things, positioning a contact side of a first component adjacent a contact side of a second component, inserting a mechanical fastener into a cavity of the first component, and rotating the mechanical fastener to drive the mechanical fastener through an interface between the contact sides of the first and second components. The interface is disposed along an interface plane and the mechanical fastener is driven through the interface in a direction that is nonperpendicular to the interface plane.

An external screw member includes a parallel screw portion and a tapered screw portion provided on a side further toward a tip end than the parallel screw portion, and a plurality of sets of step portion and a transition screw thread portion are provided on at least one of the parallel screw portion and the tapered screw portion, the step portion having a reduced thread height in a radial direction and the transition screw thread portion gradually increasing in diameter from the step portion in an anti-driving rotation direction so as to reach a thread height of a normal screw thread portion. A top portion of the transition screw thread portion is positioned at an offset toward a pressure side relative to a position of a regular screw pitch in a minimum diameter portion of the step portion, and transitions to the regular screw pitch in the anti-driving rotation direction.

A threaded fastener includes a head, a shank extending from the head, and a. cone portion. The head includes a top portion and an annular side wall extending downwardly from a periphery of the top portion. The cone portion is formed between the shank and the top portion and has a peripheral surface tapering from the top portion to the shank. An annular groove is created between the annular side wall and the cone portion for development of an accommodating space with an opening downward in a bottom of the head. The annular groove is surrounded by an inner surface of the annular side wall, the peripheral surface of the cone portion, and a bottom wall of the top portion connected between the annular side wall and the cone portion.

A screw includes a head and a shank extending from the head, and a hole-enlarging portion formed on the shank. The hole-enlarging portion features no thread and a substantially triangular transverse section. The hole-enlarging portion includes three inclined edges spaced from one another in the circumferential direction of the shank, and a guiding slope is formed between two adjacent inclined edges. The shank defines a longitudinal axis and is provided with a thread. Each inclined edge extends toward the head in an inclined direction relative to a horizontal axis perpendicular to the longitudinal axis. The inclined direction of each inclined edge is identical to a direction in which the thread extends toward the head.

A screw includes a head and a shank extending from the head and defining a longitudinal axis. A thread is provided on the shank. The head includes a top portion and a cone portion located between the top portion and the shank. A plurality of recesses is provided in a peripheral surface of the cone portion and spaced in a circumferential direction of the cone portion. Each recess includes first and second side edges opposite to each other in the circumferential direction and an upper edge connecting the first and second side edges. The first side edge features a maximum recess depth greater than a maximum recess depth of the second side edge. The top edge extending in the circumferential direction of the cone portion is partially arranged between the top portion and the first side edge of an adjacent recess in the longitudinal axis direction.

A machine for rotary driving screw anchors into underlying ground and related. The machine has a mast with a rotary driver and a mandrel driver oriented on a common axis. The mandrel driver passes a mandrel through the rotary driver and the screw anchor to allow the mandrel to be actuated ahead of the screw anchor while the rotary driver drives the screw anchor into the ground. Alternatively, the mandrel driver may also drive a hammering drill through the screw anchor to clear a path ahead of it through subsurface rocks.

A machine for rotary driving screw anchors into underlying ground and related. The machine has a mast with a rotary driver and a mandrel driver oriented on a common axis. The mandrel driver passes a mandrel through the rotary driver and the screw anchor to allow the mandrel to be actuated ahead of the screw anchor while the rotary driver drives the screw anchor into the ground. Alternatively, the mandrel driver may also drive a hammering drill through the screw anchor to clear a path ahead of it through subsurface rocks.

A screw includes: a head end, a shank and a tapered end, the head end including a tool engaging part, the head end located at one end of the shank and the tapered end located at an opposite end of the shank, wherein a thread is formed along the shank, the thread begins on the tapered end, extends onto the shank and terminates at a set location short of the head end, the thread being a right-hand thread and having a peripheral edge, at least a first helical portion of the peripheral edge includes a plurality of notches and a second helical portion of the thread lacks any notches, wherein the first helical portion is closer to the tapered end than the second helical portion, wherein the head includes an underside formed by a frustoconical part with a plurality of nibs. The head may also include an outer ledge.