An anti-pullout and low-resistance screw includes a shank, a screw-in portion, a head portion, and a thread. The thread is helically formed around both the screw-in portion and the shank and includes a plurality of thread convolutions. Each thread convolution includes an upper tooth surface facing the head portion and a lower tooth surface facing the screw-in portion. At least one tapered pressing structure is designed on the screw-in portion and/or the shank to define at least one section with its outer diameter tapering towards the screw-in portion gradually. The tapered pressing structure extends from a bottom edge of the lower tooth surface along a longitudinal axis of the shank. The lower tooth surface has a lower tooth surface height that is greater than the thread height. An annular anti-pullout plane is formed on the shank between two adjacent thread convolutions to enhance the anti-pullout strength of the screw.

An external thread member capable of performing a fastening operation efficiently without increasing the number of parts by assembling a collar into the external thread member. The external thread member 1 includes a shaft portion 5 inserted into a mounting hole 105 of a mounting member 101 through a collar 7, and the mounting member 101 is fastened to a fastening member 102. The shaft portion 5 includes a threaded portion 51 and a neck portion 52. The collar 7 is mounted on the neck portion 52 so as to be rotatable relative to each other and is engaged with the threaded portion 51 whereby retention is achieved. A counterbore hole 106 is formed in an opening close to the mounting hole 105 of an internal thread hole 104 with a tubular portion 71 inserted into the mounting hole 105 of the collar 7.

An external thread member capable of performing a fastening operation efficiently without increasing the number of parts by assembling a collar into the external thread member. The external thread member 1 includes a shaft portion 5 inserted into a mounting hole 105 of a mounting member 101 through a collar 7, and the mounting member 101 is fastened to a fastening member 102. The shaft portion 5 includes a threaded portion 51 and a neck portion 52. The collar 7 is mounted on the neck portion 52 so as to be rotatable relative to each other and is engaged with the threaded portion 51 whereby retention is achieved. A counterbore hole 106 is formed in an opening close to the mounting hole 105 of an internal thread hole 104 with a tubular portion 71 inserted into the mounting hole 105 of the collar 7.

A screw having a shank, wherein the shank has a tip end and a rear end, and a screw thread, which is connected to the shank, and which winds around the shank, wherein a wedge groove is provided in the shank, which wedge groove winds around the shank and extends alongside at least a section of the screw thread, wherein the wedge groove is delimited by a rearwardly tapered wedge flank for wedging a grout shell surrounding the shank, characterized in that the shank has a buffer zone, which extends alongside the wedge flank and alongside the screw thread, and which adjoins the wedge flank and which adjoins the screw thread, wherein the rearward taper of the wedge flank is larger than the rearward taper of the buffer zone.

A screw having a screw head and a screw shank, wherein the screw head is provided with a driving formation and the screw shank is provided at least partially with a thread. The screw shank has a cylindrical holding portion and an end portion that narrows towards a screw end, and in the holding portion the thread is formed as a standard thread. The holding portion has a circular cross section, and the end portion narrows starting from the holding portion. The end portion is provided with at least two thread turns which are formed as a forming thread, and the end portion has a polylobular cross section and the screw shank is hardened in the holding portion and in the end portion.

A screw having a shank, wherein the shank has a tip end, a rear end, and a longitudinal axis extending through the tip end and through the rear end, wherein the tip end and the rear end are opposite ends of the shank, and a screw thread, which is connected to the shank, and which winds around the shank, wherein a wedge groove is provided in the shank, which wedge groove winds around the shank and extends alongside at least a section of the screw thread, wherein the wedge groove is delimited by a rearwardly tapered wedge flank for wedging a grout shell surrounding the shank. The screw thread extends further towards the rear end of the shank than does the wedge groove.

A screw having a shank, wherein the shank has a tip end, a rear end, and a longitudinal axis extending through the tip end and through the rear end, wherein the tip end and the rear end are opposite ends of the shank, and a screw thread, which is connected to the shank, and which winds around the shank, wherein a wedge groove is provided in the shank, which wedge groove winds around the shank and extends alongside at least a section of the screw thread, wherein the wedge groove is delimited by a rearwardly tapered wedge flank for wedging a grout shell surrounding the shank. At least one ridge is provided within the wedge groove, wherein the ridge compartmentalizes the wedge groove.

A self-tapping screw (10, 30) comprising a drive (12) and a shank (14) bearing a thread comprising a main thread (16, 32), wherein the main thread (16, 32) has a maximum main thread external diameter (D.sub.AF) and a cutting area (F) and a supporting area (T) following in the direction of the drive (12), wherein the shank (14) has a threaded end (18) at an end opposite the drive (12), with the screw end (18) having a diameter (DE) of at least 20% of the maximum main thread external diameter (D.sub.AF), The shank further has, in the region of the screw end (18), a tap flute (20), wherein the tap flute (20) comprises at least two tapping thread turns (20a, 20b, 20c) which attain, in their external diameter (D.sub.AA), no more than 90% of the maximum main thread external diameter (D.sub.AF) and form a tap region in which the tapping thread turns (20a, 20b, 20c) have the same diameter development, and in addition in that the diameter of the main thread (16, 32) in the tap flute region (AB) is less than or equal to the diameter (D.sub.AA) of the tapping thread turns (20a, 20b, 20c).

A thread element mode of plastic, a connection assembly consisting of a support part made of plastic into which the thread element made of plastic has been screwed by creating a counter-thread, a method for manufacturing the connection as well as a method for manufacturing the thread element. The thread element is characterized by an axial piece on which the circumferential windings of a thread turn are interrupted by at least two chip flutes. The resulting winding areas form a cutting web and an inhibition web, whereby the cutting web extends radially beyond the inhibition web.

A thread element mode of plastic, a connection assembly consisting of a support part made of plastic into which the thread element made of plastic has been screwed by creating a counter-thread, a method for manufacturing the connection as well as a method for manufacturing the thread element. The thread element is characterized by an axial piece on which the circumferential windings of a thread turn are interrupted by at least two chip flutes. The resulting winding areas form a cutting web and an inhibition web, whereby the cutting web extends radially beyond the inhibition web.