A screw for particle board includes a head; a threaded shank; and a plurality of screw threads formed on the threaded shank. The head includes a slot on a top. The threaded shank is formed with the head and includes a shank and a tip at an end of the shank. The screw threads are formed on both the shank and the tip. The shank includes a plurality of longitudinal recesses and a plurality of longitudinal projections. Each recess is adjacent to each projection. Each screw thread is disposed between one of the recesses and the projection adjacent to the recess.

A screw includes a shank, a first thread, and a second thread. The shank includes a screw-in portion, a head portion, and a straight rod portion between the screw-in portion and the head portion. The first thread surrounds the shank spirally and includes an upper thread portion formed around the straight rod portion, a lower thread portion formed around the screw-in portion, and a middle thread portion continuously connected between the upper and lower thread portions. A plurality of serrate cutting teeth is provided on the middle thread portion of the first thread. The second thread is helically formed around the screw-in portion of the shank and includes a plurality of thread convolutions spaced from thread convolutions of the lower thread portion of the first thread. The screw can be quickly driven into articles to be joined without degradation of binding capacity between the screw and the articles.

An attachment device includes a flange, an upper shaft, and a lower shaft. The flange defines an upper surface and lower surface. The upper shaft projects from the upper surface and is centered about an upper longitudinal axis. The lower shaft projects from the lower surface and is centered about a lower longitudinal axis. The upper longitudinal axis is not collinear with the lower longitudinal axis. So configured, the attachment device allows two objects to be attached to each other with a lateral offset equal to the lateral offset between the upper shaft and the lower shaft.

The invention relates to a screw for cutting a thread into a component, having a shank which at least in portions is provided with a thread, a screw head having a drive configuration, the latter being adjoined by the shank, wherein, proceeding from an end of the shank that is opposite the head, first a cutting portion and then a holding portion are disposed, wherein the cutting portion and the holding portion are provided with a thread, wherein the holding portion has a larger external diameter in relation to the cutting portion, characterized in that a truncated-cone-type intermediate portion that is provided with a thread is disposed between the holding portion and the cutting portion, and in that the cutting portion has a truncated-cone-type attachment portion.

A flooring screw comprises a screw head, a screw shank connected with the screw head, and a cone connected with screw shank. The screw shank includes a first shank section connected with the screw head, a second shank section connected with the cone, a first thread formed on the first shank section, a second thread extended from the cone to the second shank section and running helically along a direction opposite the direction of the first thread, and a third shank section between the first shank section and the second shank section. The third shank section includes a plurality of peaks protruding outward radially and a plurality of troughs formed between the peaks and recessed radially with respect to the peaks. The peaks and the troughs form an unsmooth surface on the third shank section.

A fastener includes a shank defining a shank root, a head, a drilling portion and main threads. The main threads divide the shank root into recessed root sections. Each main thread with two cutting faces which converge at an edge is inclined to a shank axis by 60 to 82 degrees. At least one main lobe projects from the recessed root section and flares outward to at least a midpoint of at least one cutting face between the recessed root section and the edge of the main thread. The inclination allows the main threads to have a large rotating angle for increasing cutting and drilling efficiency. The extension of the main lobe supports the main thread to bear the drilling stress to prevent the shank and main threads from snapping and allow debris accommodation to provide a firm fastening effect.

A fastening nut device for fastening one substrate to another includes a cylinder, which is circumferentially larger proximate to a first end thereof, thus defining a first section and a second section of the cylinder. External threading, which is reversed, is positioned on the second section and extends from a second end of the cylinder. The cylinder can be inserted into a first hole positioned in a first substrate by counterclockwise rotation. The first section of the cylinder abuts a first face of the first substrate and the second end of the cylinder is accessible from a second face of the first substrate. A channel, which is internally threaded, extends into the cylinder from the second end. A threaded fastener, which is engaged to a second substrate, can be inserted by clockwise rotation into the channel to engage the second substrate to the second face of the first substrate.

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.

The present invention provides a fast chip removal reaming screw, including a screw head, a rod body extending from the screw head and a first thread arranged on the rod body. The rod body includes a rod body portion connected to the screw head, an reaming portion, and a pointed cone portion. The reaming portion includes first reaming blocks, second reaming blocks and third reaming blocks which are disposed in a helically staggered manner, and chip removal paths formed between the first reaming blocks, the second reaming blocks and the third reaming blocks. A first width of the chip removal path located between the first reaming blocks and a second width of the chip removal path located between the second reaming blocks are different, so that wood chips can be fast removed to reduce a stress between the screw and a wood workpiece.

A screw, especially for wood, has a knurled region (10) with two sets (11A, 11B) of ribs (11) that are offset from each other by an azimuth angle. For example, the two sets of ribs extend towards each other from opposite ends (10A, 10B) of the knurled region (10) and are intertwined only in an overlap region (12) that is at the middle of the knurled region.