Abstract: A self-drilling screw includes a shank and at least one thread. The shank includes a self-drilling portion, a head portion spaced from the self-drilling portion along a longitudinal axis, and a straight rod portion between the self-drilling portion and the head portion. The thread is spirally formed on the straight rod portion and includes a plurality of thread convolutions. Each thread convolution is provided with three to eight recesses spaced apart circumferentially, and a screw thread portion is formed between two adjacent recesses. The recess features a recess length circumferentially, and the screw thread portion features a screw thread length circumferentially. The screw thread length is 25% to 200% of the recess length. The self-drilling screw can be driven into articles to be fastened quickly without loss of binding forces between the self-drilling screw and the articles.

Abstract: A screw includes a shank and at least one thread. The shank includes a front section, a rear section spaced from the front section along a longitudinal axis of the shank, and an intermediate section between the front and rear sections. A head is formed at an upper end of the rear section. The intermediate section has circular cross sections, and the front section has roughly triangular cross sections. A plurality of separate raised teeth is provided on a circumference of the front section, and each of the plurality of raised teeth extends along the longitudinal axis of the shank. The thread is spirally formed on the shank and includes a plurality of thread convolutions.

Abstract: A self-drilling screw includes a shank and at least one thread. The shank includes a self-drilling portion, a head portion spaced from the self-drilling portion along a longitudinal axis, and a straight rod portion between the self-drilling portion and the head portion. The thread is spirally formed on the straight rod portion and includes a plurality of thread convolutions. Each thread convolution is provided with three to eight recesses spaced apart circumferentially, and a screw thread portion is formed between two adjacent recesses. The recess features a recess length circumferentially, and the screw thread portion features a screw thread length circumferentially. The screw thread length is 25% to 200% of the recess length. The self-drilling screw can be driven into articles to be fastened quickly without loss of binding forces between the self-drilling screw and the articles.

Abstract: A screw includes a shank and at least one thread. The shank includes a front section, a rear section spaced from the front section along a longitudinal axis of the shank, and an intermediate section between the front and rear sections. A head is formed at an upper end of the rear section. The intermediate section has circular cross sections, and the front section has roughly triangular cross sections. A plurality of separate raised teeth is provided on a circumference of the front section, and each of the plurality of raised teeth extends along the longitudinal axis of the shank. The thread is spirally formed on the shank and includes a plurality of thread convolutions. The screw can be quickly driven into workpieces to be combined without less combination between the screw and the workpieces.

Abstract: A screw includes a shank having an insertion tip and a head end which has an upper portion with a cutting portion and a lower portion from which a plurality of anti-screw-out teeth protrude. Each anti-screw-out tooth includes a guide face and a stop face intersecting a circumferential surface of the lower portion for development of a recessed channel. A first thread on the shank includes a plurality of asymmetrical thread convolutions each having a first cutting face facing onto the insertion tip and a second cutting face backing onto the insertion tip. The first cutting face and a horizontal axis form an included angle between 25 and 45 degrees. The second cutting face and the horizontal axis form an included angle between 3 and 23 degrees. The screw is in favor of surface flatness of a to-be-connected plank and pull-out as well as anti-screw-out properties of the screw.

Abstract: A screw includes a shank having an insertion tip and a head end which has an upper portion with a cutting portion and a lower portion from which a plurality of anti-screw-out teeth protrude. Each anti-screw-out tooth includes a guide face and a stop face intersecting a circumferential surface of the lower portion for development of a recessed channel. A first thread on the shank includes a plurality of asymmetrical thread convolutions each having a first cutting face facing onto the insertion tip and a second cutting face backing onto the insertion tip. The first cutting face and a horizontal axis form an included angle between 25 and 45 degrees. The second cutting face and the horizontal axis form an included angle between 3 and 23 degrees. The screw is in favor of surface flatness of a to-be-connected plank and pull-out as well as anti-screw-out properties of the screw.

Abstract: A screw includes a shank and at least one end cutting groove. The shank includes a lower section disposed near an insertion end thereof and an upper section disposed near a head end thereof. The lower section has triangular transverse cross sections, and the upper section has circular transverse cross sections. A first thread is disposed on the lower section of the shank, and a second thread is disposed on the upper section of the shank. A non-threaded section is disposed between the lower section and the upper section of the shank. An outer diameter of the non-threaded section is larger than an outer diameter of the upper section. The end cutting groove is formed in the lower section of the shank, and an included angle between 3 and 9 degrees is formed between an extending direction of the end cutting groove and a longitudinal axis of the shank.

Abstract: A screw includes a shank, at least one end cutting groove, a first thread, and a second thread. The shank includes a lower section disposed near an insertion end thereof and an upper section disposed near a head end thereof. The lower section has triangular transverse cross sections, and the upper section has circular transverse cross sections. The end cutting groove is formed in the lower section of the shank, and an included angle between 3 and 9 degrees is formed between an extending direction of the end cutting groove and a longitudinal axis of the shank. The first thread is disposed on the lower section of the shank and includes a plurality of asymmetrical thread convolutions.

Abstract: A screw includes a shank and at least one end cutting groove. The shank includes a lower section disposed near an insertion end thereof and an upper section disposed near a head end thereof. The lower section has triangular transverse cross sections, and the upper section has circular transverse cross sections. A first thread is disposed on the lower section of the shank, and a second thread is disposed on the upper section of the shank. A non-threaded section is disposed between the lower section and the upper section of the shank. An outer diameter of the non-threaded section is larger than an outer diameter of the upper section. The end cutting groove is formed in the lower section of the shank, and an included angle between 3 and 9 degrees is formed between an extending direction of the end cutting groove and a longitudinal axis of the shank.

Abstract: A screw includes a shank, at least one end cutting groove, a first thread, and a second thread. The shank includes a lower section disposed near an insertion end thereof and an upper section disposed near a head end thereof. The lower section has triangular transverse cross sections, and the upper section has circular transverse cross sections. The end cutting groove is formed in the lower section of the shank, and an included angle between 3 and 9 degrees is formed between an extending direction of the end cutting groove and a longitudinal axis of the shank. The first thread is disposed on the lower section of the shank and includes a plurality of asymmetrical thread convolutions.