Abstract: A combined thread forming and thread locking fastener is disclosed. A fastener includes three thread zones. A first thread zone utilizes a first thread forming thread profile with an increasing outer diameter. A second thread zone extends from the end of the first zone utilizing the first thread forming thread profile and continues with a constant diameter. The third thread zone utilizes a thread locking thread profile continuing along substantially the remainder of the shaft of a fastener.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A fastener has multiple secondary threads intertwined with a primary thread installable in a thermoplastic workpiece. A method and die are arranged for fabricating such a fastener. The fastener comprises a threaded shank portion having a primary thread of a desired form and a driver head attached thereto. At least one secondary thread is intertwined with the primary thread. In accordance with one embodiment of the invention, an outer surface of the fastener may be heated to a preselected Curie temperature during the installation of the fastener into a workpiece. The preselected Curie temperature enhances the flow of the thermoplastic material around the fastener while the fastener is being installed in the workpiece. A coating material having a particular desired Curie temperature may be applied to the fastener to produce desired driving characteristics.

Abstract: A method for gaging the geometry of selected sections of threaded fasteners comprises providing a gage for measuring a plurality of cross-sectional dimensions of the selected sections, positioning a fastener with the selected sections in surface-to-surface contact with the gage, recording information corresponding to the dimensions of the selected sections as measured by the gage to form recorded data, and ascertaining information representative of the geometry of the selected section from the recorded data.

Abstract: A method for gaging the geometry of bodies includes providing a gage for measuring a plurality of cross-sectional dimensions of a body and positioning a body in surface-to-surface contact with the gage. The method proceeds by recording information corresponding to the dimensions as measured by the gage, to form recorded data, the ascertaining information related to the geometry of the body from this recorded data. Apparatus is also provided for carrying out this method.

Abstract: A thread-forming fastener and method of installation thereof are provided for use with a workpiece constructed of a thermoplastic material. The fastener includes a threaded shank having a thread of desired form and a driver head portion. A metallic coating of a predetermined composition is applied to the threaded shank. The composition of the coating is selected for its effective Curie temperature for heating the fastener during application of the fastener to the thermoplastic workpiece. The heated surface enhances plastic flow of the thermoplastic material during thread forming and effectively reduces the required drive torque for thread forming by the fastener while increasing the holding torque. The fastener is preferably also formed with a spaced thread defining an unthreaded surface portion running adjacent to the thread at substantially the root diameter of the thread.

Abstract: A threaded fastener is presented of the thread-forming type, wherein there is defined, during driving thereof relative to a workpiece a combination of force couples and a resultant moment of force couples to develop material flow of the workpiece material about the threads to give face contact between the mating threads of the fastener and threads formed in the workpiece thereby for improved loading.

Abstract: A thread-forming screw has a point or lead thread portion having a relatively steep entry angle with respect to the screw axis. Adjacent to the point thread is a tapered thread portion of about two to three pitches in axial length. This tapered thread has a shallow entry angle defined by the taper of the maximum diameter of the thread toward the point. This shallow entry angle may be approximately 5.degree. to 8.degree. or equal to about three times the helix angle of the tapered thread. This configuration of the tapered thread results in a balanced action of thread formation and axial in-feed of the screw, resulting in a lower end pressure to initiate the thread-forming in a workpiece. A roll-threading die is contoured to provide ridges and valleys to effect the tapered thread portion.

Abstract: A thread-forming screw has a point or lead thread portion having a relatively steep entry angle with respect to the screw axis. Adjacent to the point thread is a tapered thread portion of about two to three pitches in axial length. This tapered thread has a shallow entry angle defined by the taper of the maximum diameter of the thread toward the point. This shallow entry angle may be approximately 5.degree. to 8.degree. or equal to about three times the helix angle of the tapered thread. This configuration of the tapered thread results in a balanced action of thread formation and axial in-feed of the screw, resulting in a lower end pressure to initiate the thread-forming in a workpiece. A roll-threading die is contoured to provide ridges and valleys to effect the tapered thread portion.

Abstract: An article is hardened or tempered in a localized zone. Where the article is a thread-forming device the zone is that part of its thread that does the thread-forming in the workpiece. The hardness of the remainder of the body of the article is left unchanged. The localized hardening is carried out by a method that includes high frequency induction heating only of the zone followed by quenching of the zone whereby the hardened zone is a skin of predetermined depth. A machine for making articles in accordance with the method comprises means for delivering the articles in succession to an induction heating element, a mechanism for advancing the articles through the heating element for progressive heating of the surface of the article in the localized zone to a predetermined depth, a quenching manifold for applying a spray of quenching liquid to the heated article, and means for removing the heated articles from the heating element and conveying them to the quenching manifold.

Abstract: A thread-forming screw has a work-entering section for forming a thread in a workpiece and a work-holding section adjacent thereto. Both sections are of an arcuate, polygonal lobular configuration in cross-section. The amount of lobulation on the holding section is considerably less than the lobulation on the work-entering section, which is of such magnitude as to insure effective thread-forming at low torque. The lobulation on the holding section is preferably just sufficient to effect a locking action with the thread of the workpiece and also to improve the stripping torque of the screw from the workpiece. The work-entering end of the fastener also has a pilot thread of about one turn and with a uniform width over 360.degree. and sized approximately the same as the pilot hole in the workpiece to prevent cocking of the fastener as it is initially inserted into the pilot hole. Thread-rolling dies for forming the fastener have a die section with grooves of equal depth to roll the pilot thread.

Abstract: A self-thread forming threaded fastener has a straight thread on a shank of circular cross section and a tapered thread on the work-entering end. The tapered portion of the thread is of lobular root, pitch and crest surface cross sections and which lobular configuration is continued, but to a diminishing extent, on the first few threads on the shank immediately adjacent to the tapered section. The fastener is formed by rolling between thread-rolling dies a blank having a cylindrical shank of circular cross section and an end section of arcuate lobular cross section including a tapered portion. At least the lobular and tapered portions of the blank are intermittently deflected first in one direction and then in the opposite direction by the dies. Due to such deflections of the end of the blank, a lobular tapered thread is produced on the tapered portion of the blank.