Ejot Gmbh and Co. Kg

Ejot Verbindungstechnik Gmbh & Co Kg

Ejot Verbindungstechnik Gmbh & Co.

Ejot Se & Co. Kg

Ralf Birkelbach

Ralph J Hellmig

Stephan Weitzel

Frank Dratschmidt

Ilir Selimi

Michael Achenbach

Jan Hackler

Volker Dieckmann

Juergen Behle

Rene Gerber

Gerd Weigel

Dirk Runkel

René Gerber

The invention relates to a screw (IO) in order to cut a mating thread in a plastic article, comprising a lower threaded part (F) and an upper threaded part (T), the lower threaded part having a larger diameter and its tip covering a larger surface than the upper threaded part.

Screw for screwing into plastic

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

Self-tapping screw

The invention relates to a rotationally symmetrical fastening element with an axially centralized rounded tip for a friction-welded joint with a flat component. The tip is adjoined by a conical lateral surface, the conical lateral surface transitioning into a flute for receiving a material melted during friction-welding, and by a shoulder, wherein the shoulder surrounds the flute, is axially recessed in relation to the tip and transitions into the friction-welded joint.

Fastening element for a friction-welded joint

The invention relates to a self-tapping screw, whose threads, in a rear area (facing the head), have a substantially cylindrical external diameter and, in a front area (facing away from the head), extend with an external diameter which decreases towards the end of the screw. Both in the rear area and in the front area, the threads have an asymmetrical cross section with a bisector of the flank angle, measured at the thread tips, which is located obliquly with respect to the axial course of the core and which reverses from the rear area (first cross section) towards the front area (second cross section), the bisector in the front area being inclined towards the screw head. The reversal point of the thread cross section is placed such that the first cross section is substantially present in the rear area, the second cross section substantially in the front area.

Self-tapping screw with rolled thread turns, on which the angle bisector of the thread turn formed by the load flank and the rear flank slopes away from the screw head at an angle to the perpendicular to the screw axis, the load flank running in a straight line to the thread root, and the rear flank initially extending in a straight line from the thread tip and, at about &frac13; of its height, merging via a kink into a straight angled portion at an angle that is greater than the angle, measured relative to the perpendicular, of the rear flank and is between 30&deg; and 50&deg;, the ratio of the thread's core diameter to the thread's outside diameter being greater than 0.7 and the ratio of the thread pitch to the thread's outside diameter being less than 0.25.

Self-threading screw with straight load flank and angled rear flank profile

Self-drilling and thread-forming screw having a flow-forming section

Growing community of inventors

Marburg, Germany

Ralf Birkelbach