Method of forming patch-type self-locking screw fasteners

Claim 1

A method as set forth in claim 1, wherein said thermoplastic is a poly(alkylene phthalate) having the general formula

Claim 33

A method of forming a threaded fastener having self-locking characteristics by reason of a patch of a thermoplastic polymer adhered to a plurality of unmodified threads of the fastener comprising the steps of: heating a threaded fastener to a temperature in excess of the flow point temperature of the polymer; providing a flat ribbon of a preselected thickness of the polymer having a predetermined length and of a width less than 90* of the circumferential extent relative to the threads of the fastener; placing the said flat ribbon of the polymer on the heated fastener at a preselected location thereon and simultaneously pressurely shaping the said flat ribbon to the circumference of the major diameter of the threads with sufficient work shaping pressure to hold said ribbon about the circumference of the major diameter of the threads and against longitudinal and radial movement relative to said threads for a time sufficient to cause the heated crest of the threads engaged with the ribbon to sever the ribbon into discreet segments whereby accurate predetermined quantities of the polymer formed by the discreet segments melt and flow into the valleys between adjacent crests of the threads to bond to adjacent flanks of the threads to form a unitary cohesive patch of solid material bonded to the threads of the fastener at the said preselected location thereof.

Claim 36

A method of producing a self-locking threaded fastener wherein the thread is of standard form and the self-locking characteristic is derived from a patch of thermoplastic polymeric material directly bonded to the threads of the fastener, which method comprises: heating the fastener to a temperature in excess of the melting temperature of the thermoplastic material; forming a flat ribbon of the said plastic material of a predetermined thickness having a length equal to at least the distance of three thread convolutions and of a width less than the circumference of the major diameter of the threads; applying the said ribbon the the heated fastener at a preselected location thereon by a pressure applying tool substantially conforming to the major diameter of the threads to work shape the ribbon to the major diameter of the engaged threads and to hold said ribbon, as the material thereof melts, against longitudinal and radial movement relative to said threads, whereby a predetermined quantity of the plastic flows into each valley of adjacent threads engaged by said ribbon to form a patch of the plastic bonded to the unmodified surfaces of the threads and gradually merging at its boundary edge portions into such surfaces of the thread; and after said material has flowed downwardly of the crests of the threads and into the valleys of the latter to bond to the threads at said preselected locations, quickly cooling the fastener to solidify the material.

Claim 37

A method of forming a threaded fastener having self-locking characteristics by reason of a patch of thermoplastic polymer adhered to a preselected plurality of unmodified threads of the fastener comprising the steps of: heating a threaded fastener to a temperature in excess of the flow point temperature of the polymer; providing a flat ribbon of a preseLected thickness of the polymer having a predetermined length and of a width less than the circumference of the major diameter of the threads of the fastener; placing the said flat ribbon of the polymer on the heated fastener at a preselected location thereon and simultaneously pressurely shaping the said flat ribbon to the circumference of the major diameter of the threads with sufficient work shaping pressure to hold said ribbon against longitudinal and radial movement relative to said threads for a time sufficient to cause an amount of the polymer determined by the longitudinal extent of the ribbon between adjacent crests of the threads, to flow into each valley of adjacent threads engaged with said ribbon and outwardly of the ribbon to form a unitary cohesive patch of the polymer bonded to the threads of the fastener at the preselected location thereon; and promptly thereafter abruptly cooling the fastener to solidify the polymer.

Claim 41

A method of forming a thermoplastic polymeric locking element on a screw-threaded metal fastener for locking cooperation with a complementary screw thread of a complementary member, which comprises the steps of: a. heating the metal fastener to a temperature above the melting point of the thermoplastic polymer but below the decomposition temperature thereof; b. applying a crystallizable thermoplastic poly (alkylene phthalate) polymer to the screw thread of the heated fastener, said polymer having the formula

Claim 46

A method of forming a thermoplastic polymeric locking element on a screw-threaded metal fastener for locking cooperation with a complementary screw thread of a complementary member, which comprises the steps of: a. heating the metal fastener to a temperature above the melting point of the thermoplastic polymer but below the decomposition temperature thereof; b. applying a crystallizable poly(ethylene terephthalate) thermoplastic polymer to the screw thread of the heated fastener; c. melting said polymer and permitting it to flow into intimate contact with the screw thread of the fastener; and d. cooling the fastener to a temperature below the glass transition temperature of the polymer by quenching the fastener at a temperature ranging from about -78.5* C. to 212* F.

Claim 51

A method of forming a threaded fastener having self-locking characteristics by reason of a patch of thermoplastic material adhered to a preselected plurality of unmodified threads of the fastener comprising the steps of: heating at least a preselected portion of a threaded fastener to a temperature in excess of the melting point of the thermoplastic material, but below the decomposition temperature thereof; and applying a blank of said thermoplastic material to the fastener at the preselected portion thereof for a period of time sufficient to cause the material of said blank to melt and in a molten state to flow into valleys of adjacent threads at the preselected location to bond to adjacent flanks of the threads defining the valleys to form a unitary cohesive patch of solid material at said preselected location.

Claim 53

A method of forming a threaded fastener having self-locking characteristics by reason of a patch of a thermoplastic material adhered to a plurality of unmodified threads of the fastener comprising the steps of: heating a threaded fastener to a temperature in excess of the melting point of the material; providing at least one blank of said material having a preselected thickness and length and a width less than 90* of the circumferential extent relative to the threads of the fastener; placing the said blank of the thermoplastic material on the heated fastener at a preselected location thereon and simultaneously pressurely shaping the said blank to the circumference of the major diameter of the threads with sufficient work shaping pressure to hold said blank about the circumference of the major diameter of the threads and against longitudinal and radial movement relative to said threads for a time sufficient to cause the heated crest of the threads engaged with the blank to separate the blank into segments whereby accurate predetermined quantities of the material of the segments melts and flows into the valleys between adjacent crests of the threads to bond to adjacent flanks of the threads to form a unitary cohesive patch of solid material bonded to the threads of the fastener at the said preselected location thereof.

Claim 54

A method of forming a threaded fastener having self-locking characteristics by reason of a patch of thermoplastic material adhered to a preselected plurality of unmodified threads of the fastener comprising the steps of: heating a threaded fastener to a temperature in excess of the flow point temperature of the material; providing a flat ribbon of a preselected thickness of the material having a predetermined length and of a width less than the circumference of the major diameter of the threads of the fastener; placing the said flat ribbon on the heated fastener at a preselected location thereon and simultaneously pressurely shaping the said flat ribbon to the circumference of the major diameter of the threads with sufficient work shaping pressure to hold said ribbon against longitudinal and radial movement relative to said threads for a time sufficient to cause the crests of said threads to thermally divide said ribbons into segments determined by the longitudinal extent of the ribbon between adjacent crests of the threads, whereby said segments thereafter melt and in a molten state flow into and wet each valley of adjacent threads engaged with said ribbon to form a unitary cohesive patch of the material bonded to the threads of the fastener at the preselected location thereon; and promptly thereafter abruptly cooling the fastener to solidify the material.

Claim 55

A method of forming a threaded fastener having predetermined self-locking cHaracteristics by reason of a patch of a thermoplastic material adhered to a plurality of unmodified threads of the fastener comprising the steps of: heating at least a preselected portion of a threaded fastener to a temperature in excess of the melting point of the material; providing at least one blank of the thermoplastic material of a geometrical size and shape preselected in relation to the predetermined self-locking characteristics of the fastener; placing the said blank of the thermoplastic material on the fastener at the preselected location thereon and simultaneously pressurely shaping the said blank to the circumference of the major diameter of the threads with sufficient work shaping pressure to hold said blank about the circumference of the major diameter of the threads and against longitudinal and radial movement relative to said threads for a time sufficient to cause the heated crests of the threads engaged with the blank to melt the material of the blank engaged by the crests of the threads at spaced points along the blank, and allowing the blank to remain in engagement with the threads whereby accurate predetermined quantities of the material of the blank intermediate the crests of the threads, melts and flows into the valleys between adjacent crests of the threads to bond to adjacent flanks of the threads to form a unitary cohesive patch of solid material bonded to the threads of the fastener at the said preselected location thereof.

Claim 56

A method of forming a threaded fastener having self-locking characteristics, by reason of a patch of thermoplastic material with well-defined and predetermined dimensional characteristics, adhered to a well-defined and preselected plurality of unmodified threads of the fastener, comprising the steps of: heating a threaded fastener to a temperature in excess of the melting point of the thermoplastic material, but below the decomposition temperature thereof; applying a discrete blank of said thermoplastic material having predetermined and stable dimensions to the crests of the threads of the heated fastener at a preselected location thereon, for a period of time sufficient to cause the heat from the crests of the threads to soften the material of said blank, permitting it to separate into multiple discrete segments separated by the threads of the fastener, which segments then melt and in a molten state flow into the individual valleys of adjacent threads at the preselected location, to adhere to the adjacent flanks of the threads defining the valleys, to form a unitary cohesive patch made up of multiple discrete segments of solid material at said preselected location.