Abstract: The present invention provides a method of forming pilot apertures for surgical screws. The method provides at least three points of contact to the screw shank to provide reliable positioning and retention of the bone screw. The method also provides slots or areas for insertion and retention of bone growth promoting materials which further secure the bone screw over time. The method is useful for patients of all ages, and may be particularly useful for patients that have osteoporosis or patients that are very active by providing additional securement of the bone screw to the underlying bone.

Abstract: This fastening component, which is intended to assemble a first part and a second part, includes a body extending longitudinally along an axis, a head configured to allow the fastening component to be rotated about the axis, and a tip connected to the body. The body has a side wall including fastening means configured to fasten the body to the first and second parts. The tip has a side wall having a shape different from that of a surface of revolution. The tip and the body are connected by a cleavable area configured to be broken in order to detach the tip from the body.

Abstract: An anchor for wallboard installation includes an elongated anchor body including a driving end and a wall boring end. The anchor body has a main body portion running from the driving end toward the wall boring end. The wall boring end includes a plurality of axially cutting extending teeth. The anchor body includes an internal bore and diametrically opposed slots to facilitate split of an end portion of the anchor body when the anchor is installed in a wall and a fastener is inserted for mounting an object.

Abstract: An external thread member capable of preventing oblique entry or insertion by a short screw tip shape is provided including, in its shank portion (20), a normal thread area (22), a guide thread area (24) provided at a tip side of the shank portion with respect to the normal thread area (22) and in which a guide screw thread (23) is formed, and a rising area (26) in which a transition screw thread (25) gradually rising from the guide screw thread (23) to the complete screw thread (21) is formed. A tapered guide portion (30) is provided at a tip end side of the normal thread area (22) and includes at least the guide thread area (24). The guide screw thread (23) is formed on an outer periphery of the tapered guide portion (30) which has a maximum diameter equal to or smaller than an inner diameter of an internal thread.

Abstract: A faceted lobular threaded component and methods for making and/or installing the same. A faceted lobular threaded component may include a head, and a shank extending along a longitudinal axis away from the head. The component may also include an external faceted lobular thread in the shank extending around the longitudinal axis. The external faceted lobular thread may include at least four facets per thread revolution, and at least four lobes per thread revolution circumferentially interspersed between the at least four facets and established by the at least four facets.

Abstract: A screw has a screw head and a shank extending downwardly from the screw head. The shank has a threaded segment, a cutting segment, and a tapered segment sequentially arranged downwardly, a thread spirally surrounding an external surface of the shank from the threaded segment to the tapered segment, multiple cutting ribs arranged around the external surface of the shank on the cutting segment of the shank, and multiple chip recesses formed between the cutting ribs. Each of the cutting ribs has a rounded crest to enlarge a drill hole and to reduce a resistance formed between the cutting ribs and the workpiece during drilling. The screw can be easily screwed into the workpiece with less driving force.

Abstract: A polymeric container including a base, a body, a finish, finish threads, and a tamper lip. The finish threads are at an outer surface of the finish, and are configured to cooperate with closure threads of a closure to secure the closure to the finish. The tamper lip extends from the outer surface of the finish, and is configured to replace the support flange during handling, and to cooperate with a tamper band of the closure. A recess is below the tamper lip. The recess retains the tamper band below the tamper lip when the closure is removed from cooperation with the finish. A gripper ring is between the finish threads and the tamper lip. The gripper ring is configured to cooperate with a gripper for grasping the finish.

Abstract: The present application relates to the technical field of medical instruments and provides an anti-loosening medical screw based on an organism osteogenesis function. The medical anti-loosening screw comprises a screw cap and a screw rod connected to the screw cap. The screw rod comprises a main rod and a thread spirally wound around the main rod. The cross section of the main rod is non-circular. The present medical anti-loosening screw based on an organism osteogenesis function can be applied to the medical fields such as orthopedics (spine, four limbs, pelvis, joints, etc.), maxillofacial surgery, odontology, and veterinarians and can be effectively prevented from loosening after operation after being implanted.

Abstract: A quick fastening screw includes a head, a shank with spirally-disposed thread convolutions, and a drilling portion. Each thread convolution has at least three flank sections and at least three arc sections each formed between any two adjacent flank sections. Two ends of each arc section and the flank sections adjacent to the arc section are respectively intersected to thereby form two joints. Between the two joints is formed a curved cutting portion which forms a radian not more than a quarter of a maximum thread radius so that each curved cutting portion becomes sharp to cut quickly, speed up a screwing operation, decrease the friction between the thread convolutions and a workpiece, and reduce the resistance and torque. The non-circular thread convolutions also receive cut debris efficiently and prevent the cracking of the workpiece caused by the undue accumulation of the debris.

Abstract: A thread-forming screw comprising, at least in part, a shaft (1.1) provided with a screw thread (2) and further comprising a screw tip (1.2) at one end of the shaft (1.1), wherein the shaft (1.1) comprises a thread-forming screw-threaded portion (4) that extends away from the screw tip (1.2) and an adjoining load-bearing screw-threaded portion (3), wherein the load-bearing screw-threaded portion (3) has a round cross-section, characterized in that the load-bearing screw-threaded portion (3) displays, in the direction away from the screw tip (1.2), an increase d in a flank diameter DF and/or an outside diameter DA of the screw thread at a gradient of from 1:50 to 1:500 based on a length LG of the load-bearing screw-threaded portion (3), preferably at a gradient DA or DF to LG of from 1:100 to 1:400, wherein the increase d in the flank diameter DF and/or the outside diameter DA remains constant over the length LG of the load-bearing portion.

Abstract: A bolt for peeling a coating film of the present invention includes notch parts for peeling a coating film, the notch parts being formed over a plurality of pitches at top parts of screw threads in a male screw part formed in a shaft part. The bolt is characterized in that the respective notch parts formed over the plurality of pitches are arranged to be greatly inclined at an angle of 40° to 50° to an axial line of the shaft part. Since the respective notch parts can be rolled sequentially, it is possible to form the notch parts to be deeper and sharper than conventional ones and to enhance the coating film peeling performance. Also, the coating film peeled can be discharged efficiently as compared with conventional cases.

Abstract: Embodiments of the invention provide threaded elements alone, in mating pairs, or in conjunction with other elements. Embodiments of the invention also provide for design and fabrication of such threaded elements without violating minimum feature size design rules or causing other interference issues that may result from the fabrication of such thread elements using a multi-layer multi-material electrochemical fabrication process.

Abstract: The invention relates to a self-tapping screw (1) consisting of a low-strength non-ferrous material, having a screw body (3) which is provided, at least in regions, with a coating (5), wherein the coating (5) is formed from an elastomer or polymer material enriched with fillers.

Abstract: A wave threaded fastener and system. A wave thread extends from the outer surface of the body and is made up of a profile wave and a lateral wave. The profile wave includes a plurality of profile crests and profile roots defining a plurality of profile thread widths. The lateral wave includes at least one lateral crest and at least one lateral root defining at least one wave period. Each wave period forms a period arc having a period arc angle and the sum of all period arc angles about the lateral wave equals three hundred and sixty degrees. Each of the profile crests and roots are aligned with corresponding lateral crests and roots and the wave thread travels one profile thread width per each period arc traveled.

Abstract: A fastener has a shaft, a head at a first end of the shaft, and a point at the other end of the shaft. A first portion of the shaft adjacent the point is threaded. The first portion typically extends about one-half the total length of the shaft. A second portion of the shaft (adjacent the head) is not threaded, but has a plurality of spaced rings. A knurled portion can be provided between the first and second portions, if desired. Conventional symmetrical or asymmetrical thread can be used in the threaded portion, or a three lobe thread can be used.

Abstract: A screw with low drilling resistance comprises a head portion, a shank portion, a plurality of first threads, a drilling portion, and a plurality of second threads. Wherein, a plurality of opening slots are correspondingly defined on the second threads, and a first included angle of the first threads is smaller than a second included angle of the second threads. Thereby, the opening slots on the second threads efficiently provide the first threads with an auxiliary cutting effect and preferably offers a debris accommodating room. The first threads including the smaller first included angle favorably reinforce the bearing force of the second threads including the larger second included angle, thereby promoting the cutting effect of the screw and allowing a speedy screwing.

Abstract: A fastener for composite material having a dense composition employs a head which has a socket and a recessed underside and a lower rim. The shank has an upper portion with an enlarged diameter and a left hand thread while the lower portion has a tri-lobed configuration and is traversed by a right hand thread. The right hand thread may have a plurality of notches which, in one embodiment, are arranged in a spiral array.

Abstract: An adhesive insert includes a first end and a second end, and comprises a threaded portion at the first end, the threaded portion having a circular cross-section. A securing portion is provided at the second end, the securing portion including an anti-rotation structure formed therein which resists rotation of the insert under cyclic loading by the building element. The anti-rotation structure may be a triobular cross-section formed in the securing portion. Other anti-rotation structures are provided.

Abstract: A screw with wave thread including a head, a shank extending therefrom, and a thread spirally disposed on the shank; in particular, the thread has respective first and second threaded sections. Each thread unit of the second threaded section defines a continuous wave-shaped directrix around the shank for a base. A plurality of thread segments are formed on each thread unit of the second threaded section, and each of which has an upper flank as well as a lower flank extended from the shank and disposed along the wave shape directrix to form into a wavy arrangement around shank, thereby disposing more peaks converged by the upper flank and the lower flank for increasing the drilling capability.

Abstract: It is possible to prevent a screwing torque from becoming excessively high even when a screw is threadedly engaged into a deep guide hole. In a tapping screw 100 comprising a parallel screw 22, a taper thread 23 provided closer to a tip end of the tapping screw than the parallel screw 22, and a plurality of projections 30 which partially project along an apex and flanks on both sides of a screw thread and which form an internal thread on a surface of a guide hole formed in a to-be fastened member, the plurality of projections 30 are provided from a region where the taper thread 23 is provided to a portion of a region where the parallel screw 22 is provided, and a diameter of a virtual cylinder which comes into contact with tip ends of some of the projections 30 including a projection provided in a region where the parallel screw 22 is provided is larger than an outer diameter of a external thread of the parallel screw 22.

Abstract: The present invention comprises a neck extending upwardly from a container and having an upper rim defining a neck opening. The neck has a substantially vertical sidewall of a constant thickness and at least one container neck thread extending from the sidewall. The at least one neck thread has an outer thread face drafted from a radially inward upper position to a radially outward lower position. The device further comprises a closure having a top wall and a skirt depending from the top wall, wherein the skirt is tapered. The closure comprises a closure thread extending helically along an inner surface of the skirt. The container thread has increasing radial length moving downwardly along the container neck.

Abstract: A lockbolt which includes a head portion and a shaft which extends from the head portion. The shaft includes at least a portion which is threaded and has a multi-lobular profile. A collar is swageable onto the multi-lobular threaded portion, and thereafter the lobes provide that the collar does not tend to vibrate loose from the threading. The fact that the section which has a multi-lobular profile is also threaded provides that the collar (or a conventional threaded nut) can be selectively rotatably removed and re-installed on the lockbolt. Before swaging, the collar may initially include a cylindrical bore, or a bore which is multi-faceted, preferably generally corresponding to the profile of the multi-lobular portion of the lockbolt. The lockbolt may also include a frangible pintail, wherein the multi-lobular threaded portion is disposed between the head portion of the bolt and the frangible pintail.

Abstract: A lockbolt which includes a head portion and a shaft which extends from the head portion. The shaft includes at least a portion which is threaded and has a multi-lobular profile. A collar is swageable onto the multi-lobular threaded portion, and thereafter the lobes provide that the collar does not tend to vibrate loose from the threading. The fact that the section which has a multi-lobular profile is also threaded provides that the collar (or a conventional threaded nut) can be selectively rotatably removed and re-installed on the lockbolt. Before swaging, the collar may initially include a cylindrical bore, or a bore which is multi-faceted, preferably generally corresponding to the profile of the multi-lobular portion of the lockbolt. The lockbolt may or may not include a frangible pintail.

Abstract: A self-tapping fastener, which has been especially constructed for use in connection with the insertion and installation thereof into stucco, gypsum, wallboard, or other hard board substrates, wherein the forward end portion of the shank portion of the self-tapping fastener is provided with a pair of diametrically opposed flat sections which effectively form at least one pair of diametrically opposed tapping threads so as to effectively perform the thread tapping process despite exhibiting some abrasion of the forwardmost threads. In addition, the flat sections also effectively define recessed pockets for accommodating any dust, particles, debris, or the like, which will be generated during the thread tapping process.

Abstract: A thread structure for an optical lens comprises a plastic lens barrel, and the thread structure is formed on an outer surface of the lens barrel. In each single circle of the thread structure there is a normal thread and a partial withdraw thread. The partial withdraw thread is located on a longitudinal parting line of the thread structure, a top diameter and a pitch circle diameter of the partial withdraw thread are smaller than those of the normal thread, the thread structure is provided with ribs that are located at the root of a first normal thread close to the front end of the lens barrel. The withdraw thread produces an interval between the thread structure and the base, thus preventing the burrs on the parting surface from contacting the inner threads of the base and causing powder.

Abstract: A fastener for composite material having a dense composition employs a head which has a socket and a recessed underside and a lower rim. The shank has an upper portion with an enlarged diameter and a left hand thread while the lower portion has a tri-lobed configuration and is traversed by a right hand thread. The right hand thread may have a plurality of notches which, in one embodiment, are arranged in a spiral array.

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 fastening arrangement comprising a thread-forming lobular screw and a member defining a non-tapped pilot hole therein. The screw has a shaft and a head joined to a proximal end of the shaft, the shaft defining a plurality N of lobes circumferentially spaced about a central longitudinal axis of the shaft, a thread being formed on an outer surface of the shaft. The pilot hole comprises a central portion of a diameter intermediate the minor and major diameters of the screw thread, and a plurality N of circumferentially spaced cutouts extending radially out from the central portion. A plurality of longitudinally extending edges parallel to the axis of the screw are defined at junctures between the cutouts and central portion of the pilot hole. The screw thread forms a thread in the member beginning at the longitudinal edges of the pilot hole.

Abstract: A threaded fastener comprises a first, primary thread lead, and a pair of second, auxiliary thread leads alternatively interposed between successive threads of the first, primary thread lead, except within the vicinity of the tip portion of the fastener so as to define space for accommodating debris generated during the self-tapping of the fastener into a workpiece. The fastener also comprises lobe members formed upon the primary thread lead so as to predeterminedly affect torque insertion and pull-out resistance values.

Abstract: A threaded fastener includes a lead having bosses separated from one another by bases along the thread crest. The lead-in and lead-out profiles of the bosses, and other features of the bosses and bases may differ from one another along the fastener shank. The lead-in and lead out profiles may have linear and non-linear surfaces. The lead-in and lead-out profiles may have cutting edges angled toward the direction of propagation of the bosses. The boss profiles may be selected to reduce insertion torque and to provide excellent resistance to pullout. The fastener may be formed by roll threading via a tool made by a plunge EDM process.

Abstract: A threaded fastener includes a lead having bosses separated from one another by bases along the thread crest. Two such leads may be formed such that lead-in profiles for of one lead are disposed at locations corresponding to locations of lead-out profiles for the other lead. The lead-in and lead-out profiles of the bossed, and other features of the bosses and bases may differ from one another along the fastener shank. The boss profiles may be selected to reduce insertion torque and to provide excellent resistance to pullout. The fastener may be formed by roll threading via a tool made by a plunge EDM process.

Abstract: A thread coupling for a drill string for percussive drilling has a male thread (5) and a cooperating female thread (4). The male thread is arranged on a first drill string element (3) having a first impact surface (6). The female thread is arranged on a second drill string element (2) having a second impact surface (7). The male and female threads are conical, and the crests (8) of the male thread (5) have a radius of curvature more than thirty degrees of the pitch of the thread.

Abstract: Device for securing bits of bone together, particularly small-sized bats of bone, for example bits of metatarsal head, in the form of a spindle including an elongate shank (1) followed, after a breakable region (2), by a fixator element (3) extending frustoconically to reduce in diameter in the direction of the anterior end (4), with a screw thread the pitch of which decreases progressively from the anterior end and of which the crests of the thread lie inside a coaxial geometric cylinder (D), the anterior end forming a self-drilling end.

Abstract: An assembly unit includes a component including at least one through hole and at least one screw. The screw is associated with the through hole of the component. The screw is designed and arranged to produce a thread. The screw includes a head and a supporting surface to face the component. The screw includes a shank at least partly including a thread. The screw in the region of the shank and close to the supporting surface includes an annular channel, the diameter of the annular channel being less than the core diameter of the thread of the screw and the effective axial length of the annular channel being more than the axial length of the through hole. The diameter of the through hole of the component is more than the core diameter of the thread of the screw and being less than the outer diameter of the thread of the screw.

Abstract: 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.

Abstract: 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.

Abstract: A fastener includes a head and a threaded shank. The shank defines an inner periphery and the thread defines an outer periphery. The shank and the thread each have a generally polygonal crossection with at least five lobes separated by at least five convex surfaces.

Abstract: Self-tapping screw having an at least partially non-round enveloping curve for the thread and having a penetrating section and a retaining section, it being the case that the penetrating section contains a plurality of successive thread stages which each have at least one thread turn and, along the thread stage, have essentially the same, aligned enveloping curve which runs either cylindrically or elliptically, the thread stages with an elliptical enveloping curve (elliptical thread stage) being combined such that the major axes of the successive elliptical thread stages, forming a stage group, are offset with respect to one another.

Abstract: A self-tapping fastener is provided. The fastener is formed from a blank having an odd number of lobes along a cross section taken perpendicular to its axis of rotation. The lobes define a relatively high out-of-round cross section along a tapered thread-forming zone, and a relatively low out-of-round cross section along the main body taken in a direction toward the drive head. Between the main body and tapered thread-forming zone is located an additional thread forming zone having an axial length of approximately one thread pitch and a cross section that conforms to the high out-of-round of the tapered zone. The maximum diameter (at the lobes) of the additional thread-forming section approximately matches that of the full-diameter main body section. A lower-diameter stabilizing section can be provided ahead of the tapered zone, adjacent the tip of the fastener.

Abstract: A screw includes a cylindrical shank having an upper portion formed with spiral circular threads and a lower portion formed with spiral triangular threads, each of the spiral triangular threads having three budges having three sharp edges and three pointed tips, the pointed tips of the spiral triangular threads being located at different positions, the cylindrical shank having a pointed end at a lower portion thereof, whereby the screw can be easily and rapidly turned into a piece of hard wood.

Abstract: A blank for a self tapping fastener, and corresponding fastener is provided. The blank defines an odd number of lobes along a cross section taken perpendicular to its axis of rotation. The lobes define a relatively high out-of-round cross section along a tapered thread-forming zone, and a relatively low out-of-round cross section along the main body taken in a direction toward the drive head. Between the main body and tapered thread-forming zone is located an additional thread forming zone having an axial length of approximately one thread pitch and a cross section that conforms to the high out-of-round of the tapered zone. The maximum diameter (at the lobes) of the additional thread-forming section approximately matches that of the full-diameter main body section. A lower-diameter stabilizing section can be provided ahead of the tapered zone, adjacent the tip of the fastener.

Abstract: This invention provides a terminal block capable of effectively preventing a screw in a clamping portion from being loosened. It has a block body (4), and a clamping member (10) adapted to clamp an object so as to be pressed against a clamping surface (4c) at an inner lower portion of the block body (4). The block body is formed by bending an elongated metal plate at four portions thereof at right angles in the same direction and superposing one of a first and final flaps (4a, 4b) on the other, these flaps (4a, 4b) being provided with circular threaded bores (4a', 4b') so that the threaded bores can be engaged with a shank (1b) of a screw. The clamping member (10) has a screw (1) provided with the threaded shank (1b) having an elliptical cross section being orthogonal to the axis thereof, and a clamping plate (3) joined to a lower end of the shank (1b) of the screw so that the clamping plate (3) is moved vertically in accordance with an axial movement of the screw (1).

Abstract: A threaded fastener for securing a first material to a support member is provided comprising a tapping or tap screw point at a first end, a threaded shank with three separate leads, a first portion of the shank, adjacent to the tap screw point, being of a trilobular thread design, a second portion of the shank, distal from the tap screw point, being unthreaded, and a head at an end opposite the tap screw point having an enlarged diameter and a countersunk shape to reduce the likelihood of pull through of the fastener through said first material, yet to allow the head to be introduced flush with a surface of the first material.

Abstract: The present invention envisions a fastener and a blank for forming a fastener. Threads are formed on the fastener blank of the present invention to achieve the fastener of the present invention. The fastener and blank include a shank which defines a central axis of the fastener. A head is provided on one end of the shank and a leading end is provided on an opposite end of the shank distal the head. A plurality of lobes are provided on the shank and are generally axially aligned with the central axis. Flutes are defined between neighboring lobes. The plurality of lobes include at least three major lobes and three minor lobes. The major lobes are defined by a major arc which is struck by a major radius. The minor lobes are defined by a minor arc struck by a minor radius. The major and minor radii extend from different radial points of origin.

Abstract: A fastener is constructed having four thread zones constructed over the length of the fastener, from the head to the tip, namely a ridged cylindrical holding zone, a ridged cylindrical transition thread forming zone, a rectilobular tapered thread forming zone, and a rectilobular alignment zone. The pitch cross section of the thread varies in each zone.

Abstract: A tapping screw engages a member to be engaged with a base plate made of metal by tapping a burring hole formed on the base plate. The tapping screw includes a main body having a shank and a head formed at a base end of the shank. A reduced diameter shank portion extends from a fore end portion of the shank of the main body, and has a taper angle .theta. of 9.degree. to 14.degree. and a substantially rounded triangle shaped cross-section. Recesses having no thread are formed at three faces of the reduced diameter shank portion so that a circumferential width of each recess is gradually reduced toward a tip end of the reduced diameter shank portion. Each recess is formed by a steep face facing a screwing direction of the tapping screw and a gentle face oppositely facing the steep face to form a groove.

Abstract: A thread-forming screw includes a tapered end portion having a tri-roundular cross section with three spaced flats and three threaded, round portions disposed in an alternating manner about the screw's periphery. The screw is formed by inserting a tapered blank between paired dies each having threads provided with undulations along their lengths corresponding to the circumference of the screw blank so as to form a trilobular thread on the screw which spirals around its circumference from one end of the cylindrical, untapered portion of the screw to the other in a direction opposite to that of the threads. While the untapered portion of the screw is provided with fully crested threads, the tapered end portion includes partially formed, or somewhat flattened, threads. The three spaced flats on the tapered end of the screw provide relief from contact with the workpiece into which the screw is driven for receiving deformed portions of the workpiece as the screw is driven into a workpiece aperture.

Abstract: A radial extrusion thread-forming screw (20) comprises a lead thread (36), load-bearing threads (34), and a forming thread (38). The forming thread (38) has a plurality of forming elements (50) that extend outwardly from the forming thread and which are spaced substantially circumferentially equidistant from each other. The forming thread (38) is tapered about its circumference such that the first forming element (50) moves the greatest amount of material and subsequent forming elements (50) move successively less such that each of the forming elements require substantially the same deformation force to move through the workpiece. The forming elements (50) are of a geometry which promotes deformation along slip planes in the material of the workpiece. The lead thread (36) and the load-bearing threads (34) do not have any forming elements (50) located thereon.

Abstract: The present invention discloses a fastener for a trailer bed. The trailer bed is constructed of wooden planks placed on a metal frame. The screw has twin threads with a helix angle of substantially 10.degree. to a line perpendicular to the axis of the shank or the fastener, an included angle of substantially 60.degree., and a trilobular point which allows the screw to be drilled into wooden plank and swage threads in the wooden plank and metal frame. Torquing the threads forces the fastener into the metal frame and wooden planks and allows the screw head which is tapered to seat itself.

Abstract: A thread-forming screw includes a tapered end portion formed by inserting a cylindrical blank between paired dies each having a straight portion and a tapered portion. The threads of each die are provided with undulations along their lengths corresponding to the circumference of the screw blank so as to form a trilobular thread on the screw which spirals around its circumference from one end of the screw to the other in a direction opposite to that of the threads. The cylindrical blank provides increased material at the tapered thread-forming location for forming fully crested threads, while increasing the length of the tapered portion of the die and screw provides greater stress relief for reducing the force required for thread formation and allows the screw to be driven into a workpiece more easily while maintaining a high strip force.