Research Engineering & Manufacturing, Inc.

Conti Fasteners Ag

Conti Fasteners

Alan Pritchard

Dennis O Boyer

A threaded fastener system, incorporating a bolt and a nut assembly, wherein the bolt has a threaded lead entry point whose pitch and helix angle are of a higher magnitude than that of those on the body/shank of the bolt.

Fastener system comprising an externally threaded bolt and an internally threaded nut for the avoidance of cross-threading of the mating threads during assembly

A screw recess and driver combination that comprises the use of varying frustums of differing cones to provide driver/recess contact faces that are elliptical.

Recessed head fastener and driver combination

The present invention provides a screw/bolt thread profile geometry that is particularly suited to forming a mating nut thread when the screw is inserted in to a plain diameter hole, in the anchor and rotated in a manner by which the thread helix angle will cause the relative axial forward movement, of the screw/bolt, into the anchor. This rotation and relative axial movement will be the prime mover in developing the nut thread that has mating contact with the screw/bolt thread.

High performance thread rolling screw/bolt for use in an unthreaded nut anchor

A thread forming fastener for threading into a nut anchor of a pliable material wherein there is produced during the driving of the fastener a combination of forces that encourages the nut anchor material to flow smoothly and to develop a mating thread in the nut anchor that minimizes stress cracking and radial hoop stress as the mating thread is being formed. The fastener comprises a drive head and a shank extending from the head and having a longitudinal axis, the shank including a core and a thread having a selected axial pitch, a selected thread height and a profile which in axial cross-section includes a leading face, a trailing face and a tip. The leading face is composed of a radially inner concave portion having a first radius and which transitions smoothly to a radially outer convex portion having a second radius, the transition occurring at a point on the common tangent to those portions. The trailing face is composed of a radially inner linear portion which transitions at a selected transition location to a radially outer convex portion having a third radius. The profile also includes a convex blending portion having a fourth radius which blends together the radially outer leading and trailing face portions at the tip. The thread profile produces force vectors during assembly with the nut anchor that provide enhanced mating thread strength and improved resistance to nut anchor thread breakdown.

Thread forming fastener

A thread locking fastener assembly comprising a nut anchor defining an internal thread having a longitudinal axis, a leading face and a trailing face, the internal thread, in axial section, having a profile which is symmetric about a first imaginary line extending radially out from the axis, and a fastener shank having an external thread with a longitudinal axis, a leading face and trailing face, the external thread being received in said internal thread so that said axes are substantially coincident. The external thread, in axial section, has a profile with a radially inner base zone which is symmetric about a second imaginary line extending radially from the shank axis and a radially outer deflectable addendum which is not symmetric about that line so that the addendum prevents axial centralization of the external thread profile in the internal thread profile unless a sufficient axial force is applied to the shank to deflect the addendum.

Thread locking/prevailing torque fastener and fastener assembly

A headed multi-lobed blank, method of manufacturing a self-tapping screw from the blank, and resulting multi-lobed self-tapping screw for joining thin workpieces provides desirable thread-forming characteristics at the conical tip and body portions, and improved resistance to vibrational loosening near the head. The resulting screw, obtained from the blank and method, incorporates a threaded tapered root portion between the screw head and body portion having a cross section that varies from nearly circular in the area adjacent to the underside of the head to a maximum out-of-round (or lobular) cross section at the intersection of the tapered root portion and the screw body. This shape, to combined with a thread profile outer diameter that remains largely constant from the body portion through the tapered root portion, and a multiple coil (lead thread) shape, ensure more secure holding of the screw in a thin anchor material&mdash;with the anchor material extruded axially forward and backward around the root portion.

Self-tapping screw, blank and method for joining thin workpieces and production method for the same

A threaded self-tapping screw for joining thin workpieces having a tapered root portion adjacent to the head of the screw. A plurality of threads are disposed on the body and the tapered root portion of the screw such that the radial distance from the center of the screw to the crests of the threads is maintained along both the body and the tapered root portion.

Self-tapping screw and method for joining thin workpieces

A headed multi-lobed blank, method of manufacturing a self-tapping screw from the blank, and resulting multi-lobed self-tapping screw for joining thin workpieces provides desirable thread-forming characteristics at the conical tip and body portions, and improved resistance to vibrational loosening near the head. The resulting screw, obtained from the blank and method, incorporates a threaded tapered root portion between the screw head and body portion having a cross section that varies from nearly circular in the area adjacent to the underside of the head to a maximum out-of-round (or lobular) cross section at the intersection of the tapered root portion and the screw body. This shape, combined with a thread profile outer diameter that remains largely constant from the body portion through the tapered root portion, and a multiple coil (lead thread) shape, ensure more secure holding of the screw in a thin anchor material&mdash;with the anchor material extruded axially forward and backward around the root portion.

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Almeria, Spain

Alan Pritchard