A self-tapping including a normal thread (10) and a female screw molding thread (12) having a larger diameter than that of the normal thread (10), out of pitches of the normal thread (10) positioned in a head portion side from the female screw molding thread (12), any one pitch is set to be larger than other pitches. The self-tapping not only reduces driving torques but also improves fastening force, and thus can be applied to various workpieces made of the soft material as well as a hard material.

A fastener including a chisel point that pre-bores a hole in a work piece to prevent damage to the work piece as the fastener advances. The fastener can include a head, a shaft and a chisel brake point formed at an end of the shaft. The chisel brake point can include first and second opposing inclined surfaces disposed at an angle of about 80° to about 150° relative to one another. A thread can begin adjacent the chisel brake point and form an extension of an inclined surface and/or a chisel edge. The chisel brake point can scrape material from a work piece while pre-boring a hole. The material can be transferred to the thread, and subsequently fed up the thread, out of the pre-bored hole. The chisel brake point can also selectively retard advancement of the fastener into the work piece. Methods of installing the fastener also are provided.

This threaded fastening element (2) comprising a threading (14) extending along a central axis (A), the threading (14) having at least one screw thread having an apical angle decreasing gradually, continuously and monotonously, between a first apical angle (α1) and a second apical angle (α2) strictly smaller than the first apical angle. The threaded fastening element is a screw or a nut.

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.

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 self-drilling screw composed of an austenitic or some other non-corrosive base material (1) is provided, having a shank (12), having a cutting or shaping drilling or threaded tip (16) arranged at one shank end and having a hard coating (3) applied at least to the drilling or threaded tip (16) by electrodeposition, this hard coating (3) having a layer containing a transition metal, for example a hard chromium layer. The shank (12) has a hard edge layer (2) at least under the hard coating (3). A topcoat (4) composed of a lubricating and heat-dissipating material, which preferably is metal, wax and/or lacquer, is applied to the hard coating (3).

A hole expanding screw comprises a screw head and a screw shank. The screw head includes a top and a neck extending from the top and gradually shrinking toward a direction opposite the top. The screw shank includes a shank body connected with the neck, a hole expanding portion connected with the shank body, a cone connected with the hole expanding portion, a thread running helically from the cone through the hole expanding portion to the shank body. The outer diameter of the hole expanding portion is greater than the diameter of the shank body and smaller than the diameter of the thread. The hole expanding portion includes a plurality of hole expanding blocks arranged into several rows and a plurality of debris exhaust channels formed among the hole expanding blocks, wherein each two neighboring rows of the hole expanding blocks are arranged in a staggered way.

A blind rivet-nut having an annular-flange-like setting head and a hollow shaft for securing a blind rivet-nut in an opening of a carrier. The hollow shaft has a free end having a threaded portion for receiving a threaded element of a tensioning tool. A clamping portion adjacent to the setting head forms a bead-like deformation when the tensioning tool is used to clamp the carrier between the bead-like deformation and the setting head. A threadless shaft portion is formed between the clamping portion and the threaded portion. The threadless shaft portion is threaded by a thread self-rolling or thread self-tapping fastener. The fastener is received in a positive-locking manner when the fastener is screwed into the thread formed on the previously threadless shaft portion. A method is also disclosed for securing a component to a carrier by a blind rivet-nut.

A blind rivet-nut having an annular-flange-like setting head and a hollow shaft for securing a blind rivet-nut in an opening of a carrier. The hollow shaft has a free end having a threaded portion for receiving a threaded element of a tensioning tool. A clamping portion adjacent to the setting head forms a bead-like deformation when the tensioning tool is used to clamp the carrier between the bead-like deformation and the setting head. A threadless shaft portion is formed between the clamping portion and the threaded portion. The threadless shaft portion is threaded by a thread self-rolling or thread self-tapping fastener. The fastener is received in a positive-locking manner when the fastener is screwed into the thread formed on the previously threadless shaft portion. A method is also disclosed for securing a component to a carrier by a blind rivet-nut.

A self-drilling screw (10) having a head (20), a shaft (30) at least partially wearing a thread (35) and a drill point (40). The base material of the screw (10) including the drill point (40) is integrally manufactured from an austenitic 300 series steel with a surface hardness (uncoated) of 400-600 HV 0.3. The surface of the screw has a top coating of Zn—Ni with a Ni-content between 12-15% deposited on the austenitic base material. This self-drilling screw (10) is manufactured from a blank of raw austenite 300 series steel which is initially squeezed by cold forming to reduce its diameter in a first operation and, in following cold forming operations the head, the drill point and a thread are formed.