Mating fastener recess system

Abstract

The various embodiments described herein provide a fastener system having straight wall drive surfaces that provide a reliable snap fit feature while also improving the stability of the engagement between system components. The new system features allow existing standard straight wall modification drivers to be snap fit engaged in the new system.

Description

[0001] This application is a divisional application of the invention patent application entitled "Matching Fastener Recess System", with an international application date of November 30, 2018, international application number PCT / US2018 / 063213, and national application number 201880080928.1.

[0002] Cross-reference of related applications

[0003] This application claims priority to U.S. Patent Application No. 15 / 843,789, filed December 15, 2017, and U.S. Patent Application No. 16 / 199,859, filed November 26, 2018, each of which is incorporated herein by reference in its entirety. Technical Field

[0004] This application generally relates to drive systems for threaded fasteners, tools for manufacturing said threaded fasteners, and screwdrivers for applying torque to such fasteners. More specifically, this application relates to fasteners configured with straight-walled recesses. In particular, a fastener system is constructed in which the screwdriver and the fastener engage with improved axial alignment and stick fit stability. Background Technology

[0005] Threaded fasteners used in industrial applications are typically driven by power tools at high speeds and under high torque loads. These conditions present challenging design considerations, especially with respect to the drive system, and more specifically, when the threaded fastener has a recess in the fastener head that engages with a screwdriver, or an external profile of the fastener head that engages with a screwdriver. Ideally, such a drive system needs to be easy to manufacture in terms of the geometry of the recess and head, the tools used to form the fastener head, and the screwdriver used to engage the recess or head geometry. The strength of the fastener head should not be adversely affected by the recess. When the screwdriver is engaged, it should distribute the stress load evenly to avoid the formation of highly localized stress areas that could cause deformation of the drive surface or the screwdriver, or both, thus preventing premature failure of the drive system.

[0006] When the fastener is driven, the fastener system should prevent the screwdriver from cam-out. In many applications, it is crucial that the fastener be able to withstand multiple cycles, such as in applications where fasteners must be removed for repair or replacement of parts, or for removal and replacement of access panels. Ideally, the fastener drive system should be able to perform such repeated cycles, especially in applications where the recess is coated, or in environments where the recess may become contaminated, painted, corroded, or otherwise adversely affected during use. In such applications and environments, it is critical that the drive system maintains drive engagement while applying torque in the removal direction. It may be necessary for the drive system to be able to apply even higher levels of torque when removing the fastener, such as when the fastener is over-tensioned during initial assembly, or when corrosion occurs at the interface of the mating threads, or if thermal cycling of the assembled components has already placed increased stress on the fastener. These and other features often present competing considerations; and compromises must be made to favor one over the other.

[0007] Various recessed and screwdriver configurations are commonly used, including numerous cross recesses, such as those described in U.S. Patent Re. 24,878 (Smith et al.); U.S. Patent 3,237,506 (Muenchinger); and U.S. Patent 2,474,994 (Tomalis). Other fastener geometries include multi-lobe geometries of the type described in U.S. Patent 3,763,725 (Reiland) and ribbed drive systems as described in U.S. Patent 4,187,892 (Simmons). Moreover, among common recessed configurations is the "Allen" system, which is essentially a straight-walled hexagonal socket that is well-suited for accommodating screwdrivers of similar shapes. Fastener systems with multiple convex angles having a helical configuration are described in U.S. Patents 5,957,645 (Stacy), 7,293,949 (Dilling), and 8,291,795 (Hughes). Each of these three U.S. patents is incorporated herein by reference in its entirety and will be referred to herein as an exemplary standard helical screwdriver.

[0008] Besides the ribbed system, the walls and faces of the screwdriver and the recess are typically designed to fit tightly together in an effort to achieve face-to-face contact between the driving and driven surfaces. With respect to fasteners for Phillips head recesses, this face-to-face engagement, if present, can only occur when the screwdriver is properly aligned and seated within the recess. However, as a practical matter, a certain gap must be necessary between the two for the screwdriver to be inserted into the recess.

[0009] As in Reiland's 725 patent and the Allen head system, the necessity of this clearance is even more critical for recesses with drive walls that have essentially axial alignment (straight). In all these systems, the practical consequence of this clearance is that, if any, substantial face-to-face, large-area contact is hardly achieved between the screwdriver surface and the recess surface. For most drive systems used in threaded fasteners, the screwdriver engages with the recess in the head in a manner that results in point or line contact rather than large face-to-face contact. Typically, the actual contact area is substantially smaller than that of complete face-to-face contact. As a result, when torque is applied by the screwdriver, the force applied to the screw head tends to be concentrated in localized areas, leading to higher localized stress and unstable axial alignment. This higher localized stress can cause the recess to plastically deform, forming ramps or other deformed sections, causing the screwdriver to prematurely and unintentionally disengage from the recess.

[0010] A fastener system for maximizing the engageable surface area between the screwdriver surface and the drive surface is described in Stacy'645 patent, which is generally owned with this subject application. The disclosure of the '645 patent is incorporated herein by reference. The recess and screwdriver of the '645 patent are configured to have a helical engagement surface aligned substantially parallel to the axis of the fastener and can generally be classified as a straight-wall fastener system. More robust embodiments of helical drive fastener systems are described in U.S. Patents 7,891,274 (Dilling) and 8,291,795 (Hughes), which are generally owned with this subject application. The disclosures of Dilling'274 and Hughes'795 patents are also incorporated herein by reference.

[0011] The advantages of the invention described in the '645 patent are achieved by configuring the driving surface of the screwdriver and the driven surface of the fastener to correspond to the helical segment, and particularly in such a helical configuration, that is, the helical configuration allows for a substantially wide gap between the screwdriver and the recess during insertion and removal of the screwdriver, but allows a fully sealed screwdriver to rotate to occupy that gap. The helical configuration of the driving wall of the screwdriver and the engagement wall of the recess with the screwdriver ensures that the helical walls engage over a wide area when engaged, thereby applying and distributing stress over that wide area. The driving and driven walls of the helical configuration are oriented to guide the majority of the applied torque substantially perpendicular to the fastener radius with a near-tangential engagement (if any) that is almost independent of friction.

[0012] Another example of a straight-wall fastener system is the system described in U.S. Patent 3,584,667 to Reiland. This reference is incorporated herein by reference. Reiland's '667 patent describes a fastener system in which the geometry of the drive surface consists of a series of semi-cylindrical surfaces arranged in a generally hexagonal shape. Reiland fastener systems are commonly referred to as hex-lobular (or hexalobular) and have drive surfaces parallel to the axis of the fastener.

[0013] Although straight-walled fasteners have been successfully and widely used in many applications, they encounter difficulties due to axial misalignment between the screwdriver and the fastener. Furthermore, it has been difficult to obtain a reliable frictional engagement that provides a proper fit. A proper fit feature is desired to hold the fastener in alignment on the screwdriver while it is being installed. This is particularly useful in high-volume assembly line operations using power-driven bits to apply torque to the fastener. As fastener length increases, axial alignment and proper fit remain crucial.

[0014] In many applications using straight-wall drive systems, the screwdriver may be power-driven, or require insertion into restricted access locations, or require the aid of robotic tools. In such cases, it is necessary to releasably engage the fastener with the screwdriver before installation, so that the screwdriver can be used as both an insertion tool and a screwdriver. In these applications, the screwdriver is inserted into the fastener to establish a “fit-fit.” For a fit-fit, the holding force between the screwdriver and the fastener is sufficient to hold the fastener to the screwdriver and sufficient to insert the fastener into the workpiece when the screwdriver is moved into position. After the fastener is inserted into the workpiece, the force exerted on the fastener by the workpiece upon removal of the screwdriver is sufficient to release the fit-fit. This “fit-fit” feature has been experimented with in several different types of fasteners, such as in fastener / screwdriver systems with a cross-shaped (cross-shaped geometry), several of which are shown in U.S. Patents 4,084,478 (Simmons) and 4,457,654 (Sygnator). A fastener system with a square drive geometry is shown in U.S. Patent 6,199,455 (Wagner). It was observed that the bonding effort focused on the driving surface.

[0015] U.S. Publication No. 2016 / 0305462 (Wunderlich) and U.S. Patent No. 8,955,417 (Stiebitz) illustrate six convex recesses with inclined surfaces and a mating screwdriver. In Wunderlich and Stiebitz, the inner radii of the convex recesses are separated by inclined surfaces that correspond to inclined surfaces in a particular mating screwdriver. It is observed that this configuration does not disclose a mating friction interface.

[0016] U.S. Patent 5,509,334 (Shinjo'334) and U.S. Patent 5,435,680 (Schuster) illustrate six additional convex-angled recesses having beveled surfaces and matching screwdrivers. In Shinjo'334 and Schuster, the inner radii of the convex angles of the recesses are separated by beveled surfaces that match corresponding beveled surfaces in a particular matching screwdriver. It is observed that these configurations teach a tight fit between the screwdriver and the recesses, but do not disclose a snug fit as described above.

[0017] A similar design, but with eight corner recesses, is shown in U.S. Patent 5,219,253 (Shinjo'253). It also has an undisclosed fit configuration.

[0018] The "fit-fit" feature allows fasteners to be releasably engaged with the screwdriver, enabling the screwdriver and fastener to be manipulated as a unit in hard-to-reach, automated, and other applications. Once installed, the fastener and screwdriver can be disengaged with minimal effort.

[0019] The Larson reference (US Patent 4,269,246) is interesting because it employs a partially tapered screwdriver to enhance engagement. In Larson, the inner radius of the screwdriver flutes is set parallel to the screwdriver's axis, while the tip of the convex angle tapers inward toward the tip. Its explicit purpose is to avoid premature interference between the bit and the flutes. It has been observed that this configuration results in line contact between the screwdriver and the flutes in both the circumferential and axial directions, without enhancing stability or frictional engagement.

[0020] Also of interest is reference to Goss's U.S. Patent 5,461,952. In Goss, the rear sidewall of the screwdriver is tapered to provide a gradually thickening convex geometry that creates a frictional engagement on the drive surface. Because only one sidewall is tapered, the engagement with the straight-edged drive surface becomes a circumferential contact. Again, only the bit is reconfigured. This is because it is undesirable to change the geometry of the recess, as this would result in a loss of compatibility with existing screwdrivers. Backward compatibility is a design advantage in any improved fastener system, especially a straight-wall system.

[0021] A fastener system configured to provide a close fit in a straight-walled fastener is described in U.S. Patent 7,293,949 to Dilling, a reference generally owned with this application. In Dilling's '949 patent, an interference surface is constructed on the inner non-driven transition surface between the wings of the fastener recess. However, it has been found that further improvements are desired with the addition of increased stability. Increased stability is particularly useful when the fastener recess is non-uniform. Non-uniformity can occur for a variety of reasons. Examples include, but are not limited to, machine tolerances during manufacturing, non-uniform plating, non-uniform coating, painting after fastener insertion, or deformation during insertion or prior installation or removal cycles.

[0022] The desired outcome is to provide improvements to recessed head fasteners and screwdrivers, which can reduce or eliminate the aforementioned and other difficulties and improve stability. Summary of the Invention

[0023] The various embodiments described herein provide a fastener system with a straight-walled drive surface that offers reliable fit characteristics while also improving the engagement stability between system components. A key feature of the new system is that it allows existing standard straight-walled screwdrivers to be engaged within it. To achieve this, the following describes a new recess, a new recess and screwdriver system, a new punch for forming the recess, and methods of using each of them.

[0024] A snug fit feature is desired to hold the fastener in alignment on the screwdriver while it is being installed. This is particularly useful in high-volume assembly line operations where power-driven bits apply torque to the fastener. As fastener length increases, axial alignment and snug fit are also important.

[0025] The straight-wall fastener system of this application is typically configured with a recess and a cone. The recess has a plurality of wings extending radially outward from a central axis, and the cone has a plurality of matching convex angles that engage with the wings of the recess. Each of the wings and convex angles has a driven surface, which consists of an mounting surface and a removal surface depending on the direction of the applied torque. These driven surfaces are configured to be substantially parallel to the central axis of the fastener system. Adjacent mounting and removal surfaces of the same wing or convex angle are separated at the outer radius by the outer end wall of the non-driven wing. The diameter formed by the outer radius will be referred to herein as dimension "A", as shown in the figure. Adjacent wings are separated at the inner radius by a non-driven transition profile. The diameter formed by the inner radius will be referred to herein as dimension "B", as shown in the figure.

[0026] To create an interference fit and provide a close fit, a wedge-shaped portion formed in the transition profile is created on the "B" dimension surface of the recessed wing to present a tapered interface surface. The recess is narrower in the "B" dimension relative to a standard straight-wall recess to provide engagement with a standard straight-wall screwdriver. On the other hand, the "A" dimension is also enlarged to provide additional compatibility with other standard straight-wall screwdrivers. Those skilled in the art will understand that references to "standard" screwdrivers and recesses herein refer to industry-recognized dimensions popular in the relevant market. Certain specific examples of standard recesses and screwdrivers are referenced below. The recesses provide rearward capability, thereby allowing the use of standard screwdrivers in the recesses of this application.

[0027] To form the interface for engagement between the screwdriver and the fastener, the transition profile of the recessed wing tapers inward. The interface tapers radially inward from near the top of the recess to near the bottom of the recess.

[0028] The tapered interface surface provides stability to the screwdriver to prevent improper alignment. When the recess and screwdriver are not properly aligned, the engagement causes localized areas of higher stress and leads to more severe axial misalignment. This localized higher stress can cause the recess to plastically deform, forming ramps or other deformed sections, resulting in the screwdriver prematurely and unintentionally disengaging from the recess and / or damaging the screwdriver.

[0029] High localized stress can be caused by a number of factors, such as inconsistencies in the design of the recess, the manufacturing of the fastener or screwdriver, and difficulties encountered in the field. Field difficulties may include, for example, paint or other debris that may have accumulated in the recess, misalignment of the screwdriver and fastener, or the inability to fully seat the screwdriver into the recess. Even slight misalignment between the screwdriver and fastener, or differences between the fastener or screwdriver and design specifications, can significantly reduce the contact area between the screwdriver and fastener, resulting in near-point contact of several parts of the screwdriver and fastener in many cases. Applying high torque in such situations inevitably leads to concentrated stress in the materials of the screwdriver and recess, which can then lead to material failure through plastic deformation or fracture. Even slight plastic deformation of the mating surfaces of the recess and screwdriver can adversely affect system performance. If the recess deforms to define a ramp-like surface sloping from the vertical direction, the screwdriver can slip out of the recess under the influence of the applied load. This slippage is undesirable, not only because it causes premature or uncontrollable disengagement of the screwdriver and recess, but also because a suddenly disengaged screwdriver can slide onto and damage the workpiece. Furthermore, excessive stress in the screwdriver blade during fastening can cause blade deformation, reducing the contact area with the fastener and efficiently shifting the contact area radially inward. This reduces the efficiency of the screwdriver-recess engagement and increases the risk of failure.

[0030] This application discloses a fastener having a shank and a head at the end of the shank. The shank has a central longitudinal axis, and the head has a recess centered on the axis. The recess has a plurality of wings radiating outward from the axis, the recess having an outer radius defined by a radial distance from the axis to the outermost extent of the wings. Each of the wings has a mounting drive surface and a removal drive surface, the wing drive surfaces being configured to be substantially parallel to the central longitudinal axis. In one aspect of this disclosure, the mounting drive surfaces and removal drive surfaces of adjacent wings are separated by corresponding transition profiles forming the radially innermost portion of the wings. In another aspect of this disclosure, a wedge is formed in the transition profile to present a tapered interface surface having a top, a bottom, and a pair of opposing edges, the width of the interface surface tapering from a wider portion near the top of the recess to a narrower portion near the bottom of the recess. Furthermore, in another aspect of this disclosure, the interface surface is positioned at its bottom at a radial distance from the root axis of the recess, the radial distance defining the inner radius of the recess; the interface surface is positioned at its top at a radial distance from the axis at a top, the radial distance being greater than the radial distance from the bottom. Moreover, in yet another aspect of this disclosure, the ratio of the inner radius to the outer radius of the recess is approximately 0.60 to approximately 0.65.

[0031] In another aspect, the interface surface is a non-driven surface. In yet another aspect, the interface surface is concave, with a radius of curvature equal to the radial distance from the axis to the interface surface. Furthermore, in yet another aspect, the interface surface is concave, with a radius of curvature greater than the radial distance from the axis to the interface surface. In yet another aspect, the interface surface is concave, and each portion of the interface surface is positioned such that the radial distance at the edge of the interface surface is greater than or equal to the radial distance from the axis to the transition profile. In one particular aspect, the recess is hexagonal. In another aspect, the interface surface tapers relative to the axis at an angle ranging from about half a degree (0.5°) to about twelve degrees (12°), and preferably from about four degrees (4°) to about eight degrees (8°), and more preferably about six degrees (6°).

[0032] In one aspect of this disclosure, the drive surface of the fastener head is configured to receive the drive surface of the screwdriver bit tip in an engaging engagement. In another aspect, a tapered interface surface is configured to form a frictional engagement with the screwdriver bit tip. Furthermore, in yet another aspect, the recessed interface surface is concave, and its radius of curvature is greater than the radius of curvature of the convex angle at the frictionally engaging convex angle of the interface. Moreover, in yet another aspect, the tapered interface surface is configured to form a frictional engagement with the screwdriver bit tip tip at the edge of the interface surface in the lower part of the recess.

[0033] In one aspect of this disclosure, a tapered interface surface is formed between each pair of adjacent wings. In another aspect of this disclosure, a tapered interface surface is formed between subsets of all pairs of adjacent wings. Furthermore, in another aspect of this disclosure, a plurality of tapered interface surfaces are symmetrically spaced around the recess.

[0034] This disclosure also provides a fastener system including a fastener having a shank and a head at an end of the shank, the shank having a central longitudinal axis, the head having a recess centered on the shank axis, the recess having a plurality of wings radiating outward from the shank axis, the recess having an outer radius defined by a radial distance from the shank axis to the outermost extent of the wings, each of the wings having a mounting drive surface and a removal drive surface, the wing drive surfaces being configured to be substantially parallel to the longitudinal axis of the shank, the mounting drive surfaces and removal drive surfaces of adjacent wings being separated by corresponding transition profiles forming the radially innermost portion of the wing. In another aspect of this disclosure, a wedge is formed in the transition profile to present a tapered concave interface surface having a top, a bottom, and a pair of opposing edges. The width of the interface surface tapers from a wider portion at the top of the interface surface near the top of the concave portion to a narrower portion at the bottom of the interface surface near the bottom of the concave portion. The interface surface is positioned at the bottom of the interface surface at a root radial distance from the handle axis, the root radial distance defining the inner radius of the concave portion. The interface surface is positioned at the top of the interface surface at a top radial distance from the handle axis, the top radial distance being greater than the bottom radial distance. In another aspect of this disclosure, the system includes a screwdriver with a bit end having a central longitudinal axis, and the bit end being configured to have a central portion and a plurality of protruding corners radiating outward from the central portion. Each of the protruding corners has a mounting drive surface and a removal drive surface, the mounting drive surface and removal drive surface of adjacent protruding corners being separated by a transition profile forming the radially innermost portion of the protruding corner and presenting a screwdriver interface surface, wherein the surface of the protruding corner is configured to be aligned parallel to the longitudinal axis of the screwdriver. In another aspect of this disclosure, the recess is adapted to receive the bit end, and the drive surface of the fastener head is configured to receive the drive surface of the screwdriver bit end in an engaged engagement, and the recess and the screwdriver interface surface are configured to form a frictional engagement when the fastener head and the screwdriver bit end are in the engaged engagement.

[0035] In one particular aspect of this disclosure, in the fastener system, the ratio of the inner radius of the recess to the outer radius of the recess is about 0.60 to about 0.65.

[0036] This disclosure also provides a punch for forming a head end of a recessed head fastener. In one aspect of this disclosure, the punch includes: a body having a face configured to form and define an outer contour of the head; a tip integral with the body and extending from the face, the tip having a central longitudinal axis, wherein the tip is configured to have a central portion and a plurality of wings radiating outward from the central portion, the tip having an outer radius defined by a radial distance from the axis to the outermost extent of the wings, each of the wings having a surface configured to form an mounting drive surface and a removal drive surface, the mounting drive surface and removal drive surface of adjacent wings being separated by corresponding transition portions, the contour forming the radially innermost portion of the wing, and wherein... The driving surface is configured to be substantially parallel to the central longitudinal axis and forms a wedge in the transition profile to present a tapered interface surface having a top, a bottom, and a pair of opposing edges. The width of the interface surface tapers from a wider portion at the top near the tip to a narrower portion at the bottom near the tip. The interface surface is positioned at the bottom of the interface surface at a root radial distance from the axis, the root radial distance defining the inner radius of the recess. The interface surface is positioned at the top of the interface surface at a top radial distance from the axis, the top radial distance being greater than the bottom radial distance. In one aspect of this disclosure, the ratio of the inner radius of the recess to the outer radius of the recess is about 0.60 to about 0.65.

[0037] This disclosure also provides a method for forming a threaded fastener having a screwdriver-engageable recess formed at its end, the method comprising forming the recess using a punch, the punch comprising: a body having a face configured to form and define an outer contour of the head; and a tip integral with the body and extending from the face, the tip having a central longitudinal axis, wherein the tip is configured to have a central portion and a plurality of wings radiating outward from the central portion, the tip having an outer radius defined by a radial distance from the axis to the outermost extent of the wings, each of the wings having a surface configured to form an mounting drive surface and a removal drive surface, the mounting drive surface and removal drive surface of adjacent wings being separated by corresponding transition portions. The contour forms the radially innermost portion of the wing, and wherein the drive surface is configured to be substantially parallel to the central longitudinal axis, and a wedge is formed in the transition contour to present a tapering interface surface having a top, a bottom, and a pair of opposing edges, the width of the interface surface tapering from a wider portion at the top of the interface surface near the top of the tip to a narrower portion at the bottom of the interface surface near the bottom of the tip, the interface surface being positioned at the bottom of the interface surface at a root radial distance from the axis, the root radial distance defining the inner radius of the recess, and the interface surface being positioned at the top of the interface surface at a top radial distance from the axis, the top radial distance being greater than the bottom radial distance. In another aspect of this disclosure, the ratio of the inner radius of the recess to the outer radius of the recess is about 0.60 to about 0.65.

[0038] This disclosure also provides a fastener having a head and a shank, the shank having a central longitudinal axis, wherein the head is configured to have a central portion and a plurality of wings radiating outward from the central portion, each of the wings having an mounting drive surface and a removal drive surface, the mounting drive surface and the removal drive surface being separated by a non-driven transition profile forming the radially innermost portion of the wing, and wherein the drive surface is configured to be substantially parallel to the central longitudinal axis of the fastener, and a wedge-shaped portion is formed in the non-driven transition profile of the fastener wing to present a tapered interface surface.

[0039] These and other features and advantages will become clearer from the following detailed description of embodiments of this application and the accompanying drawings. Attached Figure Description

[0040] Figure 1 This is a perspective view of an exemplary fastener recess according to the disclosed embodiments.

[0041] Figure 2 yes Figure 1 A top view of the concave part.

[0042] Figure 3 It is along Figure 2 The view taken by section line III-III.

[0043] Figure 4 This is a top view of a standard recess.

[0044] Figure 5 It is shown that... Figure 4 The concave contours overlap Figure 2 A schematic diagram of the concave contour.

[0045] Figure 6 yes Figure 5 A magnified view of detail VI.

[0046] Figure 7 This is a top view of a standard screwdriver engaging with a standard recess.

[0047] Figure 8 It is along Figure 7 The view taken by section line VIII-VIII.

[0048] Figure 9 This is a top view of a standard screwdriver engaging with an exemplary recess according to a disclosed embodiment.

[0049] Figure 10 It is along Figure 9 The view captured by the section line XX.

[0050] Figure 11 This is a top view of a standard screwdriver engaging with an exemplary recess according to a disclosed embodiment.

[0051] Figure 12 It is along Figure 11 The view taken by section line XII-XII.

[0052] Figure 13 This is a perspective view of an exemplary punch according to the disclosed embodiments.

[0053] Figure 14 yes Figure 13 End view of the punch.

[0054] Figure 15 yes Figure 13 Side view of the punch.

[0055] Figure 16 It is along Figure 14 The view captured by the section line XVI-XVI.

[0056] Figure 17 This is a perspective view of an exemplary fastener recess according to the disclosed embodiments.

[0057] Figure 18 This is a perspective view of an exemplary fastener protrusion according to the disclosed embodiments.

[0058] Figure 19 This is a cross-sectional view of an exemplary fastener recess according to the disclosed embodiments.

[0059] Figure 20 It is a polar coordinate diagram of a constant gap helix according to the disclosed embodiments.

[0060] Figure 21 It is a force diagram showing the force balance between the screwdriver and the recess according to the disclosed embodiment.

[0061] Figure 22 It is a force diagram showing the force balance between the screwdriver and the recess in the prior art.

[0062] Figure 23 is a perspective view of an exemplary fastener protrusion according to the disclosed embodiment.

[0063] Figure 24 is a plan view of the recess shown in Figure 23.

[0064] Figure 25 is a perspective view of an exemplary fastener protrusion according to the disclosed embodiment.

[0065] Figure 26 is a plan view of the protrusion shown in Figure 25. Detailed Implementation

[0066] Although the invention has been described with reference to embodiments shown in the accompanying drawings, it should be understood that the invention may have alternative forms. Furthermore, elements or materials of any suitable size, shape, or type may be used. Throughout this specification, similar reference numerals refer to similar features in all the drawings.

[0067] Now refer to Figures 1 to 3 The diagram illustrates a fastener recess according to an exemplary embodiment. The fastener 20 includes a shank 24 having a central longitudinal axis 26. A head 22 is positioned at an end 25 of the shank 24. The head 22 has six convex star-shaped recesses 40 centered on the axis 26. Each recess 40 has six wings 42 radiating outward from the axis 26. Each recess 40 has an outer radius 57 defined by a radial distance from the axis 26 to the outermost extent of the wings. Each wing 42 has a mounting drive surface 43 and a removal drive surface 44 (collectively referred to as drive walls) spaced apart by an outer end wall 41. The wing drive surfaces 43, 44 are configured to be substantially parallel to the central longitudinal axis 26.

[0068] The mounting drive surface 43 and the removal drive surface 44 of adjacent wings 42 are separated by corresponding transition profiles 45, which form the radially innermost portion of the wing 42. A wedge-shaped portion is formed in this transition profile to present a tapered interface surface 50. The interface surface 50 is a non-drive surface. Each interface surface 50 has a top 51, a bottom 52, and a pair of opposing edges 53, 55. Each opposing edge 53, 55 creates a transition from each mounting and removal surface to the interface surface. The advantages of edges 53, 55 will be discussed below. The width 58 of the interface surface tapers from a wider portion at the top 51 of the interface surface shown as near the top 48 of the recess 40 to a narrower portion at the bottom 52 of the interface surface shown as near the bottom 46 of the recess 40.

[0069] The recess extends into the head 22 to reach a bottom 46, which may include a bottom beveled cone 49 that transitions from the bottom of the interface surface 50 and the drive walls 43, 44 and the outer end wall 41 of the wing to the bottom 46. A top beveled cone 47 transitions from the top surface 21 of the head to the top 48 of the recess. However, alternative embodiments may omit the top beveled cone 47. It should be noted that in alternative embodiments, the top 51 and bottom 52 of the interface surfaces need not be adjacent to the top 48 and bottom 46 of the recess 40, respectively. In such embodiments, the top 51 and bottom 52 of each interface surface may be offset from the top 48 and bottom 46 of the recess, respectively.

[0070] Interface surface 50 is positioned at its bottom 52 at a radial distance 56 from the root (or bottom) of axis 26. This radial distance defines the inner radius 56 of the recess. Interface surface 50 is positioned at its top 51 at a radial distance 59 from the top of axis 26. This radial distance 59 is greater than the inner radius (root or bottom radial distance) 56 of the recess. The ratio of the inner radius 56 to the outer radius 57 of the recess is approximately 0.60 to approximately 0.65. In another example, the ratio of the inner radius 56 to the outer radius 57 of the recess is 0.60 to 0.65. In one example, the ratio of the inner radius 56 to the outer radius 57 of the recess is approximately 0.64, and in another example, the ratio is equal to 0.64.

[0071] In one example, the tapered interface surface 50 is concave relative to axis 26. However, the tapered interface surface can also be flat. The tapered interface surface 50 can also have alternative shapes if edges 53, 55 are formed. In a particular concave configuration, the radius of curvature of the tapered interface surface 50 is equal to the radial distance from axis 26 to interface surface 50. That is, the radius of curvature of the tapered interface surface 50 decreases from the top 51 of interface 50 to the bottom 52 of interface surface 50. In an alternative embodiment, the radius of curvature of the concave tapered interface surface 50 is greater than the distance from axis to interface surface. In another alternative embodiment, each portion of the concave interface surface is positioned such that the radial distance at the interface surface edges 53, 55 is greater than or equal to the radial distance from axis 26 to transition profile 45.

[0072] The interface surface 50 is at a cone angle 54 relative to the axis 26, ranging from approximately half a degree (0.5°) to approximately twelve degrees (12°). Figure 3 The cone angle 54 is gradually tapered. In a particular embodiment, the cone angle 54 is preferably about four degrees (4°) to about eight degrees (8°), and more preferably about six degrees (6°).

[0073] Figures 1 to 3 The tapered interface surface 50 formed between each pair of adjacent winglets 42 is shown. However, in some applications, it would be advantageous to construct interference profiles only between selected pairs (i.e., a subset of transition profiles), which is understood to mean that some misalignment may frequently occur. This can be avoided to some extent, for example in multi-convex configurations, by constructing interference profiles symmetrically around the recesses (e.g., between opposing winglet pairs, between winglet pairs opposite along the diameter, between every other pair of winglets, or in a triangular configuration).

[0074] Figure 4 This illustrates an example of a standard hexagonal threaded fastener with a straight-walled drive surface, based on existing technology. An exemplary standard hexagonal recess (also known as...) The recesses are those fasteners manufactured according to ISO 10664:2014 and NAS1800 (REV.4) standards, each of which is incorporated herein by reference in its entirety. Each size of a standard hexagonal recess has a correspondingly engaging standard hexagonal screwdriver. Another example of a standard hexagonal recess and its corresponding screwdriver is described in Hughes' 795 patent. Each of these recesses will be referred to herein together as an exemplary standard hexagonal recess, and their corresponding screwdrivers will be referred to as exemplary standard hexagonal screwdrivers.

[0075] The term "straight-walled drive surface" can be used herein to refer to a fastener system in which the drive surface is substantially aligned with, or parallel to, the longitudinal axis of the fastener. In the fastener industry, it is generally accepted that statements such as "parallel alignment" are subject to certain tolerances; it should be understood that such alignment is affected by manufacturing tolerances and will vary slightly in practice. Specifically, Figure 4 An exemplary standard hexagonal recess is shown, which is also described in Hughes' 795 patent. Figure 2 (element 30). Refer to this application. Figure 4 A fastener system with a standard hexagonal recess is configured to have a fastener 120 and an engaging screwdriver bit (not shown). The fastener 120 is configured to have a head 122 and a threaded shank (not shown). In this example, a hexagonal recess 140 is formed in the head 122, its drive surface aligned parallel to (straight wall) the axis 126 of the fastener 120. The recess 140 has an outer radius 157 defined by a radial distance from the axis 126 to the outermost extent of the wing 142. The mounting surface 143 and removal surface 144 of adjacent wings are separated by a transition profile 145, and each of the mounting surface 143 and removal surface 144 of the same wing is separated by an outer end wall 141. The recess has an inner radius 156 defined by a radial distance from the axis 126 to the transition profile 145. For example, referring to Shinjo '334, ISO 10664:2014, and NAS1800 (REV.4) standards, the ratio of the inner radius 156 to the outer radius 157 of the recess in a standard hexagonal screwdriver is between 0.70 and 0.75 (depending on the screwdriver size), which is greater than the ratio of the inner radius 56 to the outer radius 57 of the recess 40 of this application. As will be discussed below, the smaller ratio of the inner radius 56 to the outer radius 57 of the recess 40 results in many advantageous benefits, including improved torque per lob of the engaging screwdriver.

[0076] Figure 5 It is shown that... Figure 4 The concave portion 140 (standard hexagonal concave portion) has an overlapping contour. Figure 2 A schematic diagram of the outline of the recess 40 (an exemplary recess of this application). Figure 6 yes Figure 5 A magnified view of detail VI. Figure 5 and Figure 6 The outline of the recess 40 is shown in dashed lines, particularly the outline of the bottom 52 of the interface surface 50, where the outline of the recess 40 overlaps with the outline of the standard recess 140. Although the geometry of the recess 140 in this particular illustration is similar to the hexagonal type fastener system in the Reiland reference cited above, it is intended only as an example of the use of the invention in comparison to the standard straight-walled recess. Of course, Figure 5 and Figure 6 It is not intended to indicate that the two recesses can be used simultaneously, but is only used to illustrate the relative positions of the exemplary recess 40 feature and the standard recess 140 feature.

[0077] Compared to the transition profile 145 of the recess 140, the interface surface 50 of the recess 40 extends closer (radially) to the axis 26 (the bottom 52 of the interface surface 50 is shown in dashed lines). Therefore, the inner radius 156 of the recess 140 ( Figure 4 ) is greater than the inner radius 56 ( Figure 2 Furthermore, compared to the transition wing outer wall 141 of the recess 140, the wing outer wall 41 of the recess 40 extends further (radially) from the axis 26. Therefore, the outer radius 157 of the recess 140 is... Figure 4 The outer radius of the concave portion is less than 40 (57). Figure 2 Each of these features, namely the smaller inner radius 56 and the larger outer radius 57, results in an increased drive wall and provides improved drive torque from the screwdriver to the recess at each convex corner. (See below for reference.) Figure 9 Discuss this feature.

[0078] Figure 7 A top view of a standard hexagonal screwdriver 220 engaging with a standard hexagonal recess 140 is shown. The screwdriver 220 has a bit end, shown in cross-section. The screwdriver and bit end will be referred to together as screwdriver 220. Screwdriver 220 includes features that match those of the standard recess 140, including, for example, a central longitudinal axis 226, a central portion, and a plurality of convex angles 242 radiating outward from the central portion, which convex angles 242 engage with the recess wing 142. Each of the plurality of convex angles 242 has a corresponding mounting surface 243 and a removal surface 244. Additionally, screwdriver 220 includes a transition profile 245 between adjacent convex angles 242 and an outer end wall 241 of the convex angle between the mounting surface 243 and the removal surface 244 of the same convex angle 242. Each surface of the convex angle 242 is configured to be aligned parallel to the longitudinal axis 226 of the screwdriver.

[0079] As described above, and in fact, in order for the standard hexagonal screwdriver 220 to be inserted into the standard hexagonal recess 140, there must be a certain gap 250 between them. This gap is the same around the circumference of the screwdriver 220.

[0080] Figure 8 It is along Figure 7The view is taken from section lines VIII-VIII. Apart from the standard hexagonal screwdriver 220 and the standard hexagonal recess 140, each of the recess transition profile 145 and screwdriver transition profile 245 has straight walls; that is, each of them is parallel to axis 125 (within machining tolerances). Therefore, if the standard screwdriver 220 is coaxial with the standard recess 140 and does not enhance the stability or frictional engagement of the screwdriver / recess joint, the clearance 250 remains constant. Although clearance 250 allows the standard screwdriver 220 to be easily inserted into the standard recess 140, the screwdriver 220 is prone to accidental misalignment or wobble in the recess 140 (axis 226 not aligned with axis 126). Wobble helps concentrate force on the screw head in localized areas, resulting in higher localized stress and unstable alignment. This high local stress can cause the recess to plastically deform, forming a ramp or other deformed section, which can cause the screwdriver to detach from the recess prematurely and accidentally, leading to slippage and damage to the screwdriver / recess.

[0081] Figure 9 The same standard hexagonal screwdriver 220 is shown engaging with the exemplary recess 40. The exemplary recess 40 is configured to receive, in the engaging engagement, any screwdriver made corresponding to the standard hexagonal recess described above. Figure 2 As shown, the recess 40 is configured to have a tapered interference surface 50, which is formed in the "B"-sized surface of the recess transition profile 45. As previously stated, the inner radius 56 of the recess 40 ( Figure 2 ) is less than the inner radius of the standard hexagonal concave part of 156 ( Figure 4 This is because the tapered interface surface / wedge 50 tapers towards the axis 26. Furthermore, the inner radius 56 of the recess is smaller than the top radial distance 59.

[0082] The recess is 140 degrees relative to the standard hexagonal recess. Figure 7 The cone 220 narrows to provide frictional engagement when the fastener 20 and the screwdriver 220 are in an engaging engagement. The inner radius 256 of the screwdriver 220 is greater than the inner radius 56 of the recess and less than the top radial distance 59, thereby creating a negative clearance, i.e., interference, at the interface regions 302, 304, as described below. As shown, the dimension “A” is also relative to the standard hexagonal recess 140 ( Figure 7 The "B" dimension is enlarged to allow for greater compatibility with other standard hexagonal screwdrivers (e.g., those described in Hughes' 795 patent). However, in alternative embodiments, only the "B" dimension is narrowed while the "A" dimension remains as is for... Figure 4 The standard recess size of the type of fastener shown improves the alignment stability of the standard hexagonal screwdriver, but at the cost of additional compatibility.

[0083] Continue to refer to Figure 9 and Figure 10 The tapered interface surface 50 is configured to provide significant frictional engagement (“fit”) at edges 53, 55, resulting in two separate interface regions 302, 304. Because the opposing edges 53, 55 are at the transition from each mounting and removal surface to the interface surface, less material deformation is required to achieve a sufficient fit when the screwdriver is inserted. The contact in the lower portion of the recess also provides a smaller contact area, which further improves the fit. By providing two points of stability at each interface surface 50, the two interface regions 302, 304 increase the stability of the contact between the recess 40 and the screwdriver 220, thereby improving axial alignment and reducing the risk of slippage. Better stability is provided by having two interface regions opposite to a single line or surface contact. A fit is generated where the straight wall transition profile 245 contacts the tapered interface surface 50. It should be noted that if there is sufficient contact at interface regions 302, 304, some inclination in the screwdriver wall can still provide a sufficient fit. The improved fit of the exemplary recess 40 increases the speed at which fasteners are applied to the workpiece and reduces slippage and screwdriver / recess damage. The degree of fit can be adjusted during the manufacture of the recess by adjusting the taper angle 54. Depending on the specific configuration of a standard six-face screwdriver, each interface region 302, 304 can be a combination of point and line contacts along the edges 53, 55. Regardless of the type of contact, there are two interface regions 302, 304 between each tapered interface surface 50 and the screwdriver transition profile 245. By helping to minimize the wobble of the screwdriver within the recess, the two interface regions 302, 304 provide increased stability for the engagement of the screwdriver bit with the recess compared to prior art recesses, thereby significantly improving the axial alignment and engagement of the convex and wing. This is particularly useful when the fastener 20 is non-uniform. Non-uniformity can occur for a variety of reasons. Examples include, but are not limited to, machine tolerances during manufacturing, non-uniform plating, non-uniform coatings, painting after fastener insertion, or deformation during insertion or prior installation or removal cycles. Exemplary coatings include, but are not limited to, electroplated zinc & clear, electroplated zinc & yellow, electroplated zinc & wax, mechanical zinc & clear, mechanical zinc & yellow, black phosphate, black phosphate and oil, oil, wax, nickel, cadmium & wax, hot-dip galvanizing, and dacrotizing. It should be noted that in some examples, such as when the screwdriver and fastener are not perfectly axially aligned, or due to manufacturing tolerances in use, two interface areas may not be established in each recessed wing. However, throughout the engagement process, a close fit and stability advantage can still be achieved with sufficient interface areas.

[0084] In addition to the increased stability provided by the frictional interfaces at interface regions 302, 304, the inner radius 56 of the recess 40 is smaller than the inner radius 156 of the standard hexagonal recess 140. The smaller inner radius 56, coupled with the tapered interface surface 50, causes the tapered interface surface 50 to contact the screwdriver more closely than the central axis 226. This provides additional drive wall for transmitting torque, as indicated by the screwdriver cam engagement length 310. This results in a drive wall ratio of approximately 0.15 to approximately 0.21 for the “AT” size. In a particular embodiment, the drive wall ratio is preferably approximately 0.17 to approximately 0.19, and more preferably approximately 0.18. The increased drive wall ratio improves the bit-to-recess drive torque at each cam. This increased drive wall ratio is an advantage when engaging with a standard hexagonal screwdriver compared to a standard hexagonal recess utilizing a drive wall ratio of 0.11 according to the hexagonal recess standard.

[0085] Figure 10 It is along Figure 9 The figure shows a view taken by section line XX, through the interface regions 302 opposite in diameter. This illustrates frictional engagement occurring in the lower portion of the recess between the screwdriver tip and the tapered interface surface 50 at interface region 302. In an alternative embodiment, the tapered interface surface 50 appears at interface region 304 in the lower third of the recess. A small gap 310 is provided between the screwdriver 220 and the recess 40 during engagement to ensure contact rather than bottom-feeding at interface regions 302, 304, allowing for plating build-up at the bottom of the recess and also preventing damage to the screwdriver tip 220.

[0086] Figures 11 to 12 Another standard hexagonal screwdriver 420, namely the hexagonal screwdriver described in Hughes' 795 patent, is shown engaging with the recess 40. Due to the improved configuration of the recess 40, the fastener 20 is able to provide engagement with multiple hexagonal screwdrivers, including the Hughes' 795 patent screwdriver. Screwdriver 420 includes a central longitudinal axis 426, a central portion, and multiple lobes 442 radiating outward from the central portion. Adjacent lobes 442 are separated by a transition profile 445. As compared to the standard hexagonal screwdriver 220 and as described in the Hughes' 795 patent, the lobes 442 have been extended in the "AH" dimension between the opposing lobe outer end walls 441.

[0087] The inner radius of the 420 screwdriver, 456, is greater than the inner radius of the concave part, 56. Figure 2 And less than the top radial distance of 59 ( Figures 2 to 3 This creates a negative gap, i.e., interference, at interface regions 402 and 404. The engagement of the screwdriver 420 and the recess 40 provides a reference... Figure 9and Figure 10 The advantages mentioned above are similar to those of reduced wobbling and increased drive-to-wall ratio, which improve the bit-to-recess drive torque at each convex corner. Figure 12 It is along Figure 11 The figure shows a view taken along section line XII-XII, passing through interface regions 402 opposite in diameter. This figure illustrates frictional engagement occurring in the lower portion of the recess between the screwdriver tip and the tapered interface surface 50 at interface region 402. In an alternative embodiment, the tapered interface surface 50 appears at interface region 304 in the lower third of the recess. (For reference only) Figure 10 For the same reason discussed, a smaller clearance 410 is provided between the screwdriver 220 and the recess 40 during engagement.

[0088] The aforementioned features can be applied to other straight-wall fastener systems with similar results. As another embodiment, the helical drive system of the cited standard helical screwdriver patent can be improved by constructing a tapered interface surface / wedge on the relative "B"-sized transition profile.

[0089] For example, Table 1 shows example dimensions "A" and "B" in inches at the outermost part of the wing and at the transition profile, respectively. Such screwdrivers and corresponding recesses can be formed according to SAE International Standard AS6305 (published January 2017) and are available from Phillips Screw Company. TM In the drive system Purchased under spiral. SAE international standard AS6305 (published in January 2017) is incorporated herein by reference in its entirety.

[0090] Table 1:

[0091]

[0092]

[0093] The recess of this application can be manufactured in a conventional two-blow header machine. Typically, the punch will be formed to include a body and a tip, said body and tip being adapted to form the head of a fastener having the disclosed corresponding recess. Figures 1 to 3 and Figures 9 to 11 The punch can be formed using conventional punch forming techniques, such as using hobbing dies. Alternatively, conventional techniques can be used, such as stamping the screwdriver blank with one or more forming dies to form the desired wing shape, or milling the screwdriver bit using a profiled milling cutter, to manufacture the screwdriver according to the invention.

[0094] Reference Figures 13 to 16 The disclosed exemplary recess can be formed by an upsetting punch adapted to form the head of a fastener having the corresponding disclosed recess. The recess can be formed, for example, in a two-punch upsetting machine using conventional upsetting techniques. Figures 13 to 16 A punch 520 is shown, configured to form an exemplary disclosed recess 40. The punch is relative to... Figures 1 to 3 and Figures 9 to 11 The negative shape of the described recess 40 embodiment corresponds to the positive shape. Therefore, the features and dimensions described with reference to the disclosed punch 520 also apply to the corresponding recess 40 features and embodiments, and vice versa.

[0095] The punch includes a body portion (not shown) having a face (not shown) and an integrally formed tip 540 projecting from that face. The tip 540 is complementary to the shape of the recess, and the face of the punch has a shape complementary to the shape of the intended screw head, which in Figure 3 The tip 540 is shown as a flat head. The tip 540 includes a top-beveled tapered forming portion 547 with a bevel angle 564. The tip 540 has a hexagonal star configuration centered on axis 526. The tip 540 has six wing forming portions 542 radiating outward from axis 526. The tip 540 has a tip outer radius 557, defined by the radial distance from axis 526 to the outermost extent of the wing forming portions 542. Each of the wing forming portions 542 has a mounting drive surface forming portion 543 and a removal drive surface forming portion 544 (collectively referred to as drive wall forming portions) separated by an outer end wall forming portion 541. The outer end wall forming portion 541 has a depth 566. The wing drive surface forming portions 543, 544 are configured to be substantially parallel to the central longitudinal axis 526.

[0096] The mounting drive surface forming portion 543 and the removal drive surface forming portion 544 of adjacent wing forming portions 542 are separated by corresponding transition profile forming portions 545, which form the radially innermost portion of the wing forming portion 542. A wedge-shaped portion is formed in the transition profile forming portion 545 to present a tapered interface surface forming portion 550. The interface surface forming portion 550 forms a non-drive surface. An additional advantage of the location of the interface surface forming portion 550 is that, for example, the interface surface 50 is easier to form with a punch at a dimension "B" compared to, for example, a recess at dimension "A," as in the Hughes' 795 patent. Forming the interface surface at dimension "B" reduces the risk of material being punched away from the exterior of the wing during manufacturing.

[0097] Each interface surface forming portion 550 has a top forming portion 551, a bottom forming portion 552, and a pair of opposing edge forming portions 553, 555. The advantages of the edge forming portions 553, 555 have been discussed above with reference to the opposing edges 53 and 55 of the recess 40. Furthermore, because the edges 53 and 55 taper to a point near the bottom 46 of the recess 40, in this example, the punch 520 can remove more material and the process of forming the recess is more efficient through the edge forming portions 553, 555. The width 558 of the interface surface forming portion 550 tapers from a wider portion at the top forming portion 551 of the interface surface shown as near the top forming portion 548 of the recess 540 to a narrower portion at the bottom forming portion 552 of the interface surface forming portion 550 shown as near the bottom forming portion 546 of the recess 540.

[0098] The pointed end 540 extends to the bottom forming portion 546 of the recess, which may include a bottom beveled tapered forming portion 549 that transitions from the bottom forming portions of the interface surface forming portion 550 and the drive wall forming portions 543, 544, and the outer end wall forming portion 541 of the wing to the bottom forming portion 546. The bottom beveled tapered forming portion has a bevel angle 562. A top beveled tapered forming portion 547 transitions from the top forming portion 548 of the body portion of the recess. However, alternative embodiments may exclude the top beveled tapered forming portion 547. It should be noted that in alternative embodiments, the top forming portion 551 and the bottom forming portion 552 of the interface surface forming portion need not be close to the top forming portion 548 and the bottom forming portion 546 of the recess forming portion 540, respectively. In such embodiments, the top forming portion 551 and the bottom forming portion 552 of each interface surface forming portion may be offset from the top forming portion 548 and the bottom forming portion 546 of the recess forming portion, respectively.

[0099] The interface surface forming portion 550 is positioned at a bottom forming portion 552 of the interface surface forming portion 550, a radial distance 556 from the root (or bottom) of the axis 526. The root radial distance 556 defines the inner radius 556 of the recess forming portion. The interface surface forming portion 550 is positioned at a top forming portion 551 of the interface surface forming portion 550, a radial distance 559 from the top forming portion of the axis 526. The top forming portion radial distance 559 is greater than the inner radius (root or bottom radial distance) 556 of the recess forming portion. The ratio of the inner radius 556 of the recess forming portion to the outer radius 557 of the tip is about 0.60 to about 0.65. In one example, the ratio of the inner radius 556 of the recess forming portion to the outer radius 557 of the tip is about 0.64, and in another example, the ratio of the inner radius 556 of the recess forming portion to the outer radius 557 of the tip is equal to 0.64.

[0100] The tapered interface surface forming portion 550 is concave relative to the axis 526. However, the tapered interface surface forming portion 550 can also be flat. If edge forming portions 553 and 555 are formed, the tapered interface surface forming portion 550 can also have an alternative shape. In a particular concave configuration, the radius of curvature of the tapered interface surface forming portion 550 is equal to the radial distance from the axis 26 to the interface surface forming portion 550. That is, the radius of curvature of the tapered interface surface forming portion 550 decreases from the top forming portion 551 to the bottom forming portion 552. In an alternative embodiment, the radius of curvature of the concave tapered interface surface forming portion 550 is constant and equal to the radial distance 559 of the top forming portion. In another alternative embodiment, each portion of the concave interface surface forming portion 550 is positioned such that the radial distance at the interface surface edge forming portions 553, 555 is greater than or equal to the radial distance from axis 26 to transition profile forming portion 545.

[0101] The interface surface forming portion 550 tapers relative to the axis 26 at an angle from about half a degree (0.5°) to about twelve degrees (12°). In a particular embodiment, the interface surface forming portion 550 preferably tapers at a cone angle 554 from about four degrees (4°) to about eight degrees (8°), and more preferably about six degrees (6°). Figure 3 (Gradually shrinks)

[0102] Figures 13 to 16 The diagram shows tapered interface surface forming portions 550 formed between each pair of adjacent wing forming portions 542. However, in some applications, it is advantageous to construct interference profiles only between selected pairs (i.e., subsets of transition profiles), which is understood to mean that some misalignment may frequently occur. This can be avoided to some extent, for example in multi-convex configurations, by constructing interference profiles symmetrically around the recesses (e.g., between opposing wing pairs, between wing pairs opposite in diameter, between every other pair of wings, or in a triangular configuration).

[0103] Threaded fasteners are formed with recesses that engage with screwdrivers, such as recess 40 ( Figures 1 to 3 In this way, the recess that engages with the screwdriver engages with the corresponding standard six-corner screwdriver as described above by mechanically forming the head and the recess. The head 22 can be formed in a conventional two-punch upsetting machine, in which the end of a wire or other material used to make a fastener is supported in the die of the upsetting machine, and its head end is first impacted by a punch that partially forms the head, and then by a finishing punch, as described in reference... Figures 12 to 15As described above, the finishing punch completes the head and forms a recess that engages with the screwdriver. The general manufacture of fasteners is well known and will not be further described in this application. Various such well-known methods can be used to construct this subject matter.

[0104] Figures 17 to 2 Each of the following illustrates various embodiments of tapered interface surfaces / wedges implemented in various helical drive fastener systems (e.g., helical drive fasteners and screwdrivers discussed in Stacy'645 and Dilling'274 patents), and is modified to include the tapered interface surfaces / wedges described above. Each of these will be discussed in more detail below.

[0105] Reference Figure 17 According to an exemplary embodiment, a portion of fastener 620 and screwdriver 621 is shown. For clarity, the remainder of fastener 620 and screwdriver 621 is omitted. Fastener 620 includes a recess 640 and a plurality of wings 642. Each wing 642 includes a helical mounting surface 643 and a removal surface 644, each separated by a transition wing outer wall 641. Screwdriver 621 is configured with a helical drive surface that engages with the corresponding surface of fastener recess 640, establishing a fit as described above. Similar to prior art helical fasteners, the overall shape and number of wings may differ from the example shown. The overall shapes of the recess 640 and the screwdriver 621 are similar, except that the wing of the screwdriver 621 is smaller than the corresponding wing 642 of the recess 640 to provide a gap between the screwdriver and the fastener to facilitate engagement and removal of the screwdriver 621 from the recess 640. Additionally, the screwdriver bit mounting wall and removal wall differ slightly from the corresponding recess walls, so that rotation of the bit will provide a complete face-to-face engagement on both the removal wall and the mounting wall. As described above, the screwdriver / fastener interface surfaces are constructed in the general shape of the helical segment on both the mounting surface and the removal surface.

[0106] The transition profile 645 extends between the mounting surface and the removal surface of the adjacent wing. A wedge is formed in the transition profile 645 to present a tapered interface surface 650. The tapered interface surface 650 is configured in the same manner and provides the aforementioned tapered interface surface 50 for the recess 640. Figure 1 Advantages of ).

[0107] Figure 18 Show as Figure 17 The combination of fastener 620 and screwdriver 621, and the combination of fastener 720 and screwdriver 721, except in Figure 18In an exemplary embodiment, the "recess" is located in the screwdriver, which will be referred to herein as a slot or screwdriver slot 739. Although Figure 17 The recess 640 in fastener 620 and screwdriver 621 is shown as a "positive" shape designed to be inserted into the "negative" shape of recess 640, but in Figure 18 In some embodiments, the reverse is also true. For example... Figure 18 As shown, the fastener 720 includes a protrusion 740 configured to extend axially outward from the fastener head 722 for engaging with the screwdriver slot 721. Similar to the recess 640 ( Figure 17 The protrusion 740 includes a plurality of wings 742. Each wing 742 includes a mounting surface 743 and a removal surface 744 in a helical configuration, each of which is separated by a transition wing outer wall 741. A transition profile 745 extends between the mounting and removal surfaces of adjacent wings. A wedge is formed in the transition profile 745 to present a tapered interface surface 750. The tapered interface surface 750 is configured in the same manner and provides the protrusion 740 with the advantages of the tapered interface surface 50 described above. It should be noted that the tapered interface surface 750 is shown as extending less than the entire height of the protrusion 740. As previously mentioned regarding the tapered interface surface 50 ( Figure 1 As described, the tapered interface surface can be offset from the top and / or bottom of the recess / convex portion, respectively.

[0108] The screwdriver slot 721 is configured with a matching drive surface for engaging with the drive surface of the protrusion 740, and for establishing an interface region with the tapered interface surface 750, as described above regarding the tapered interface surface 50. Figure 1 As described in ).

[0109] exist Figure 19 Two exemplary helical configurations are shown. The helical recess 840 (indicated by dashed lines) is, for example, similar to the embodiment described in the Stacy '645 patent, and the high-strength helical recess 940 is, for example, similar to the embodiment described in the Dilling '274 patent. Figure 17 Implementation examples. See also... Figure 19 Each of the described configurations is equally applicable Figure 17 and Figure 18 Each of the embodiments disclosed herein, as well as other embodiments thereof. Figure 19This configuration shown also applies to fastener recesses, protrusions, or their corresponding screwdrivers, as it should be understood that only a small gap is provided between the fastener and the screwdriver for inserting and removing the screwdriver. It should be noted that, according to this disclosure, the recess is constructed with the disclosed interface surface / wedge shape. For example, the screwdriver bit tip is made to have a radius at the transition profile (half the screwdriver "B" size), which is greater than the radial distance of the recess root of the improved recess and less than the radial distance of the recess top. For simplicity, in Figure 19 The tapered interface surfaces are not shown (e.g., 650 and 750 of the corresponding fasteners 620 and 720).

[0110] The helical recess 840 is shown in dashed lines and has a wing 842 that extends outward from a core 812 having a radius (R2') and is defined by a mounting drive surface 843 and a removal drive surface 844. See below for further discussion. Figure 20 At least one defined helical segment in the sidewall (e.g., drive surfaces 843, 844).

[0111] Figure 20 An ideal helix in polar coordinates is shown, possessing the desired characteristics for use in a helical configuration. This ideal helix can be oriented relative to a rotational axis corresponding to the longitudinal axis of the threaded fastener, and when rotated in this way, it will remain parallel to and spaced from the unrotated helix by an angle θ. Figure 20 As shown, the ideal helix indicated at position A will remain parallel to the helix at position A when rotated by an angle θ to the position indicated at position B, but will be separated from the helix at position A by a gap indicated at position C. Although the size of the gap C will increase with increasing rotation angle θ, for any given angle θ, the gap C will remain constant over the length of the helix. The geometry of the constant gap helix is ​​defined by the following equation, expressed in polar coordinates:

[0112]

[0113] in:

[0114] θ = the angle of rotation (in radians) of the ray that crosses the curve at a distance r from the axis of rotation;

[0115] R i =The initial radius measured from the axis of rotation to the starting point of the helix; and

[0116] R = the radius of the spiral at the rotation angle θ, which is also measured from the axis of rotation.

[0117] From the foregoing, it should be understood that when a screwdriver is formed with a drive wall that embodies a constant gap helix and is driven to engage the helical wall of the recess, the helical drive wall on the screwdriver will engage the corresponding helical drive wall on the recess completely and simultaneously. Figure 20 The polar coordinate diagram is intended only to illustrate an ideal spiral, where the gap between the spiral's rotational positions is constant, i.e., a constant-gap spiral, such that the spiral can be considered parallel.

[0118] According to this disclosure, one or more helical surfaces on the drive wall of the wing portion of the recess are positioned such that the starting point 1054 of the helix is ​​radially spaced from the central axis 1044 of the recess by a radius R. i According to the invention, the portions of the helical surface closer to the starting point 1054 will transmit a larger portion of the applied torque along the direction in which the screw will be rotatably driven than the portions positioned further outward. By configuring those helical surfaces to correspond to the portions of the helix positioned closer to the starting point 1054, the helical conical surface and the recesses that engage with the conical surface will transmit torque most efficiently. According to the invention, the force transmission wall should be bent to conform to the helix's... Figure 20 The portion extending from R=1 to no more than about R=3.5 (indicated at point 1062) and more preferably from R=1 to about R=2 corresponds to this portion. Considering the angular aspect of the arc surrounded by the desired inner portion of the spiral, this angle may include at most about 125°, more preferably about 90° or less, and most preferably about 45° or less.

[0119] Figure 21 and Figure 22 It is a force diagram showing the component forces acting at any point along the curved surfaces of the joined screwdriver wall and recessed wall. Figure 21 A force diagram for use in this invention is shown. Figure 21 A screwdriver 1034B is shown, which has a removal drive wall 1048B that engages face-to-face with the removal wall 1026B of a recessed fastener head 1016B along a curved interface 1068. Figure 21The diagram schematically illustrates the force vector when a counter-clockwise torque, as suggested at 1070, is applied around the screw's axis 1044B. At the selected point of interest 1072, the screwdriver 1034B applies a force 1074 to the recessed surface 1026B in a direction orthogonal to the interface 1068. The normal force 1074 is decomposed into a component 1076 that applies torque only to the screw and another component 1078 that generates radially outward compressive stress but not torque. Additionally, the normal force 1074 results in a frictional force 1080 that points along the tangent 1082 toward the interface 1068. The frictional force 1080 is further decomposed into a component 1084 and another component 1086, which adds to the torque component 1076 and decreases relative to and opposite the radially outward component 1078. The magnitude of the frictional force 1080 relative to the normal force 1074 depends on the coefficient of friction, which will naturally vary with the surface smoothness, lubricity, and material of the screw. The coefficient of friction can, for example, be in the range between approximately 0.1 and 0.4. Figure 21 and Figure 22 In its development efforts, a friction coefficient of 0.4 has been chosen. Therefore, Figure 21 As shown, by means of the geometry of the driving and driven walls of the present invention, for illustrative purposes it is assumed that, even at higher coefficients of friction, the torque is primarily generated by the normal component 1074. The torque transmission capability of the fastener embodying the present invention does not depend to any significant extent on the vector component 1084 of the frictional force.

[0120] Figure 22 Is with Figure 21 A similar force diagram is shown, but illustrating the effect of the screwdriver-recessed curved interface 1068', which is oriented such that the tangent 1082' of the curved interface 1068' at point 1072' is oriented closer to being perpendicular to the radius drawn from the screw axis 1044B' to point 1072'. This arrangement is typically characterized by features described in Bradshaw's U.S. Patent No. 2,248,695. Figure 22 and Figure 21A comparison will make it obvious that the prior art configuration results in a generally higher radially outward load on the screw head (as demonstrated by the difference between the lengths of vector component 1078' and vector component 1086'), and depends primarily on the variable and often unpredictable frictional phenomena that generate torque. The dependence on friction in the prior art is evident by comparing the relative contributions of frictional components 1084' and 1076'. Based on the foregoing, it can be understood that a line perpendicular to the tangent of the helical segment will form an angle α with the radius from the longitudinal axis to the point of tangency, which represents the extent to which the force applied by the screwdriver will be transmitted as torque to the fastener. In the embodiments disclosed herein, this angle α should be no less than 17°, and preferably significantly greater than 17°. One of the important objectives of the present invention is to provide a drive system by which higher torque can be transmitted from the screwdriver to the fastener while reducing the risk of screw head yielding or breakage, without significantly relying on frictional characteristics.

[0121] Return to reference Figure 19 The spiral recesses 840 and 940 are of high strength, wherein wings 842 and 942 include spiral drive walls in both the mounting and removal directions, but one of the drive walls in each wing has a larger torque capacity than the other. Recesses 840 and 940 provide a greater torque capacity in the removal direction because the removal drive wall has a larger arc length and corresponding area than the mounting drive wall. Because force is applied over a larger surface area along the removal direction, a greater torque can be applied in that direction.

[0122] Although the present invention can be carried out most efficiently with the aforementioned constant-gap helix, a system comprising a helix that differs somewhat from the most preferred basic constant-gap helix can be provided while still offering significant advantages over the prior art. Figure 19 Examples of such recesses 840 and 940 are shown. For example, the recess is shown having four wings 842 and 942, each wing having a removal drive wall 844 and 944 and a mounting drive wall 843 and 943, the removal drive walls 844 and 944 being configured with a constant-gap helix, and the mounting drive walls 843 and 943 having different helical configurations oriented to direct most of the force from the screwdriver in the torque-generating direction to the recess. In one example, the transition profile 845 of the mounting surface and the removal surface on each of the screwdriver and recess wings can be formed in an arcuate profile.

[0123] Compared to the high-strength recess 940, it was observed that the cross-sectional shape of the high-strength recess 940 was configured to have an increased core radius (R2) exceeding that of the helical recess 840 (R2'). The overall radius R1 remained constant, thus requiring a shortening of the height h of the wing 942 to accommodate the increased core radius R2. This resulted in a reduction in the surface area used for the drive surface and anticipated performance deficiencies. The cross-section of the wing 942 was further modified by moving the mounting surface 943 and the removal surface 944 outwards in a parallel manner to form a truncated wing shape with an outer end wall 941. The outer end wall 941 was configured to conform to a segment concentric with the core 912 and having a diameter larger than the core diameter. The drive surfaces 943 and 944 were configured to intersect the core diameter in the transition profile 945 between adjacent wings (e.g., wings 942a and 942d with transition profile 945d). The transition profile 945 has a concave shape that matches the core diameter.

[0124] Wings 942a, 942b, 942c, and 942d are defined by mounting drive surfaces 943a, 943b, 943c, and 943d, wing outer end walls 941a, 941b, 941c, and 941d, and removing drive surfaces 944a, 944b, 944c, and 944d, respectively. Adjacent wings intersect with the core circumference 912 in transition profiles 945a, 945b, 945c, and 945d.

[0125] In lieu of performance deficiencies, these changes have resulted in a remarkable increase in screwdriver strength and a significant improvement in the settling torque capability for helical drive fastener systems. The reduction in drive surface area is offset by improved distribution characteristics from the drive surface to the core.

[0126] The increased strength and seating torque of the high-strength recess 940 and the corresponding screwdriver can be attributed to the recess and screwdriver being configured with an increased core diameter exceeding that of prior art helical fastener systems. Logically, it would be illogical to attempt to maintain the area of ​​the drive surface by constructing the transition surfaces as a convex continuum of the mounting surface 943 and the removal surface 944 (similar to prior art designs). Instead, the drive surfaces 943 and 944 are configured to intersect the core diameter in a transition profile 945 between the wings 942, the transition profile 945 having a concave form conforming to the core diameter. This increases core strength but further shortens the wing cross-section and reduces the drive surface area. Furthermore, by shortening the outer tip of the wing cross-section and moving the drive surface outward in parallel with prior art configurations, the wings can be enlarged and formed with blunt tips, thereby further improving the system strength. It is observed that the center of mass of the wings also shifts outward, resulting in improved load distribution.

[0127] This is accompanied by a shortening of the radial extension of the wings of both the concave and screwdriver cross sections beyond the core diameter. The wing cross sections of the screwdriver / concave are further modified by moving the mounting and removal surfaces in a parallel manner to form a truncated wing shape with a blunt tip. The blunt tip is configured to conform to a circle concentric with the core and having a diameter larger than the core diameter.

[0128] To achieve this, the cross-section of the wing portion of the high-strength recess 940 (and therefore the corresponding wing portion of the screwdriver) is truncated outward from the core circumference 912 and inward from the outer end wall 941 of the wing. In this way, the wing 942 is configured such that the ratio of the core radius R2 to the wing tip radius R1 is greater than 0.55, and the transition profile 945 between the wings 942 is a concave segment of the core circumference. Preferably, the R2 / R1 ratio is in the range of 0.65 to 0.70. Additionally, the width w of the wing 942 is increased while maintaining the profile of the drive surface consistent with prior art fastener systems. The ratio h / w of the wing cross-section height h is configured to be approximately equal to or less than 0.5. In contrast, for example, see reference... Figure 19 recess 840, ratio R'2 / R i It can be calculated to be approximately 0.46, and the ratio (h' / w') of the spiral recess 840 can be calculated to be approximately 0.93. These modified dimensions have been shown to provide a significantly advantageous improvement in bit strength to the recess 940.

[0129] Figure 23 shows an example of a helical recess 1140 within the head of fastener 1120 and a corresponding screwdriver 1121 with six wings. Recess 1140 has the same characteristics as recess 640 ( Figure 17 ) and 940 Figure 19 Similar characteristics include multiple tapered interface surfaces 1150 between adjacent wings 1142. Recess 1140 includes six wings 1142, compared to the embodiments of recesses 640 and 940 which have four wings. Figure 24 is a plan view of recess 1140 viewed downwards from the longitudinal axis of fastener 1120 (Figure 23).

[0130] Figure 25 shows an example of a spiral-shaped protrusion 1240 extending from the head of fastener 1220 and a corresponding screwdriver 1221 with six wings. Protrusion 1240 has the same characteristics as protrusion 740 ( Figure 18 ) and recess 940 ( Figure 19 Similar characteristics include multiple tapered interface surfaces 1250 between adjacent wings 1242. Compared to the embodiment of the protrusion 740 with four wings, the protrusion 1240 includes six wings 1242. Figure 26 is a plan view of the protrusion 1240 viewed downwards from the longitudinal axis of the fastener 1220 (Figure 25).

[0131] The above description and accompanying drawings are merely illustrative of specific embodiments for realizing the features and advantages described herein. Modifications and substitutions may be made to specific conditions and materials in other ways. Fasteners are constructed in many different configurations, and the application of this application is not intended to be limited to any particular type. For example, Figures 1 to 3 The recess 40 in the embodiment is hexagonal. However, the principles of this disclosure can be applied to recess systems having three, four, five, eight, or other numbers of fins and convex corners. As another example, the above-described embodiments are illustrated as a common form of fastener system comprising a concave recess on the fastener and a screwdriver with a convex configuration. However, the interference profile of the fastener system of this intent can also be applied to opposing arrangements having a concave recess (slot) on the screwdriver and a fastener with a convex configuration as described in some of the above embodiments. For another example, some fasteners do not have a head for clamping the workpiece to the substrate. Instead, they can use a second threaded segment to engage the workpiece. Although some fasteners have a clamping head, the advantages provided by the illustrated configuration can also be obtained in other fastener types (e.g., non-clamping fasteners and others). Therefore, the invention is not to be considered limited by the foregoing description and drawings, but is intended to include all such alternatives, modifications, substitutions, and variations.

[0132] The novel content that is claimed to be patentable is as described in the claims.

Claims

1. A screwdriver for driving fasteners comprising: a female screwdriver defining a central longitudinal axis and a recess centered on the central longitudinal axis and adapted to receive a fastener of a male configuration, the recess comprising: a plurality of wing portions radiating outwardly from the central longitudinal axis; each of the wing portions having a driving surface for installation and a driving surface for removal configured to be aligned substantially parallel to the central longitudinal axis; the driving surfaces for installation and removal of adjacent wing portions being separated by a respective transition profile forming a radially innermost portion of the wing portions; a wedge formed in the transition profile to present a tapered interface surface having a top, a bottom, and a pair of opposing edges, the interface surface tapering in width from a wider portion at the top of the interface surface proximate the top of the recess to a narrower portion at the bottom of the interface surface proximate the bottom of the recess; and the interface surface positioned a root radial distance from the central longitudinal axis at the bottom of the interface surface defining a recess inner radius, the interface surface positioned a top radial distance from the central longitudinal axis at the top of the interface surface, the top radial distance greater than the root radial distance; wherein the recess is for receiving a male portion of the fastener of the male configuration for installation or removal of the fastener of the male configuration such that one of the driving surfaces for installation and removal of the wing portions of the recess engages the male portion along an entire male angle engagement length perpendicular to the central longitudinal axis, and such that a ratio of the male angle engagement length to a maximum diameter of the male portion perpendicular to the central longitudinal axis is 0.15 to 0.

21.

2. The screwdriver of claim 1, wherein, the interface surface configured to form a frictional engagement with the fastener of the male configuration at two interface regions separated from each other.

3. The screwdriver of claim 2, wherein, the two interface regions are entirely in a lower third of the recess.

4. The screwdriver of claim 1 wherein, the interface surface is a non-driving surface.

5. The screwdriver of claim 1 wherein, the interface surface is concave having a radius of curvature equal to a radial distance from the central longitudinal axis to the interface surface.

6. The screwdriver of claim 1, wherein, the interface surface is concave having a radius of curvature greater than a radial distance from the central longitudinal axis to the interface surface.

7. The screwdriver of claim 1 wherein, the interface surface is concave, each portion of the interface surface positioned a radial distance from the central longitudinal axis greater than or equal to a radial distance from the central longitudinal axis to the transition profile at the interface surface edge.

8. The screwdriver of claim 1 wherein, the recess has six wing portions or four wing portions.

9. The screwdriver of claim 1, wherein, the interface surface tapers at an angle relative to the central longitudinal axis, the angle in a range of 0.5° to 12°.

10. The screwdriver of claim 9, wherein, the angle is in a range of 4° to 8°.

11. The screwdriver of claim 10, wherein, the angle is 6°.

12. The screwdriver of claim 1, wherein, the tapered interface surface is configured to form a frictional engagement with the fastener of the male configuration.

13. The screwdriver of claim 1, wherein, the tapered interface surface is configured to form a frictional engagement with the fastener of the male configuration at an edge of a lower portion of the recess.

14. The screwdriver of claim 1, wherein, At least one of the installation and removal driving surfaces is configured to define a spiral having a starting point spaced an initial radius from the central longitudinal axis and extending to an outer end point at a radius no more than 3.5 times the initial radius.

15. The screwdriver of claim 14, wherein, A portion of the spiral lacks a tangent line whose perpendicular line makes an angle with a radius from the central longitudinal axis to a point of tangency of less than 17°.

16. The screwdriver of claim 14, wherein, The spiral comprises a constant gap spiral.

17. The screwdriver of claim 14, wherein, The spiral is defined by the equation where: θ = the rotational angle (in radians) of a ray across the spiral at a distance from the axis of rotation; R i = initial radius measured from the axis of rotation to the starting point of the spiral; and R = the radius of the spiral measured from the axis of rotation at the rotational angle θ.

18. The screwdriver of claim 14, wherein, The spiral extends from a starting point to an outer end point at a radius three times the initial radius.

19. The screwdriver of claim 14, wherein, An arc of the spiral circumscribed by at least one of the installation and removal driving surfaces is no more than 125°.

20. A fastener system comprising: a convexly configured fastener having a convex portion defining a convexity; and a screwdriver for driving the fastener, the screwdriver comprising: a concave screwdriver defining a central longitudinal axis and a concavity centered on the central longitudinal axis and adapted to receive the convexity of the convexly configured fastener, the concavity comprising: a plurality of wings radiating outwardly from the central longitudinal axis; each of the wings having an installation driving surface and a removal driving surface configured to align substantially parallel to the central longitudinal axis; the installation and removal driving surfaces of adjacent wings being separated by a respective transition profile forming a radially innermost portion of the wings; a wedge formed in the transition profile to present a tapered interface surface having a top, a bottom, and a pair of opposing edges, the interface surface tapering in width from a wider portion at the top of the interface surface proximate the top of the concavity to a narrower portion at the bottom of the interface surface proximate the bottom of the concavity; and the interface surface positioned a root radial distance from the central longitudinal axis at the bottom of the interface surface defining a concavity inner radius, the interface surface positioned a top radial distance from the central longitudinal axis at the top of the interface surface, the top radial distance greater than the root radial distance; wherein the screwdriver and the fastener are arranged such that the concavity can receive the convexity of the convexly configured fastener to install or remove the convexly configured fastener such that one of the installation and removal driving surfaces of the wings of the concavity engages the convexity along an entire convex angle engagement length perpendicular to the central longitudinal axis and such that the ratio of the convex angle engagement length to the maximum diameter of the convexity perpendicular to the central longitudinal axis is 0.15 to 0.

21.

21. The fastener system of claim 20, wherein, the interface surface configured to form a frictional engagement with the convexly configured fastener at two interface regions separate from one another.

22. The fastener system of claim 21, wherein, The two interface regions are entirely in the lower third of the recess.

23. The fastener system of claim 20, wherein, The interface surface is a non-driving surface.

24. The fastener system of claim 20, wherein, The interface surface is concave with a radius of curvature equal to a radial distance from the central longitudinal axis to the interface surface.

25. The fastener system of claim 20, wherein, The interface surface is concave with a radius of curvature greater than a radial distance from the central longitudinal axis to the interface surface.

26. The fastener system of claim 20, wherein, The interface surface is concave, each portion of the interface surface being positioned at a radial distance from the central longitudinal axis greater than or equal to a radial distance from the central longitudinal axis to the transition profile at an edge of the interface surface.

27. The fastener system of claim 20, wherein, The recess has six wings or four wings.

28. The fastener system of claim 20, wherein, The interface surface tapers at an angle relative to the central longitudinal axis, the angle being in the range of 0.5° to 12°.

29. The fastener system of claim 28, wherein, The angle is in the range of 4° to 8°.

30. The fastener system of claim 29, wherein, The angle is 6°.

31. The fastener system of claim 20, wherein, The tapered interface surface is configured to form a frictional engagement with the fastener of the male configuration.

32. The fastener system of claim 20, wherein, The tapered interface surface is configured to form a frictional engagement with the fastener of the male configuration at an edge of a lower portion of the recess.

33. The fastener system of claim 20, wherein, At least one of the installation driving surface and removal driving surface is configured to define a spiral having a starting point spaced an initial radius from the central longitudinal axis and extending to an outer endpoint at a radius no more than 3.5 times the initial radius.

34. The fastener system of claim 33, wherein, A portion of the spiral lacks a tangent line having a perpendicular line at an angle less than 17° from a radius from the central longitudinal axis to a point of tangency.

35. The fastener system of claim 33, wherein, The spiral comprises a constant gap spiral.

36. The fastener system of claim 33, wherein, The spiral is defined by the equation where: θ = the angle of rotation (in radians) of a ray across the spiral at a distance from the axis of rotation; R i = initial radius measured from the axis of rotation to the starting point of the spiral; and R = the radius of the spiral measured from the axis of rotation at the angle of rotation θ.

37. The fastener system of claim 33, wherein, The spiral extends from a starting point to an outer endpoint, the radius at the outer endpoint being three times the initial radius.

38. The fastener system of claim 33, wherein, An arc of the spiral circumscribed by at least one of the installation driving surface and removal driving surface is no more than 125°.

39. A threaded fastener, comprising: a fastener of a male configuration having a head, a threaded shaft defining a central longitudinal axis, and a male portion defining a lobe extending axially outwardly from the head, the lobe including a central portion and a plurality of lobes radiating outwardly from the central portion, wherein: each of the lobes has an installation driving surface and a removal driving surface configured to be aligned substantially parallel to the central longitudinal axis; the installation driving surface and removal driving surface of adjacent lobes are separated by a respective transition profile forming a radially innermost portion of the lobe; a wedge is formed in the transition profile to present a tapered interface surface having a top, a bottom, and a pair of opposing edges, a width of the interface surface tapering from a wider portion at the top of the interface surface proximate the top of the lobe to a narrower portion at the bottom of the interface surface proximate the bottom of the lobe; and the tapered interface surface is configured to form a frictional engagement with the fastener of the male configuration. the interface surface is positioned a root radial distance from the central longitudinal axis at a bottom of the interface surface, the root radial distance defining an inner radius, the interface surface is positioned a top radial distance from the central longitudinal axis at a top of the interface surface, the top radial distance being greater than the root radial distance; wherein the threaded fastener is configured such that a socket of a socket configuration having a recess can receive a protrusion of the fastener of the protrusion configuration in the recess to install or remove the fastener of the protrusion configuration such that one of an installation drive surface and a removal drive surface of the protrusion of the protrusion is engaged with the recess along an entire protrusion angle of the protrusion that is perpendicular to the central longitudinal axis, and such that a ratio of the protrusion angle to a maximum diameter of the protrusion that is perpendicular to the central longitudinal axis is 0.15 to 0.

21.

40. The threaded fastener of claim 39, wherein, the interface surface is configured to form a frictional engagement with a socket of a socket configuration.

41. The threaded fastener of claim 39, wherein, the interface surface is a non-drive surface.

42. The threaded fastener of claim 39, wherein, the protrusion has six protrusion angles.

43. The threaded fastener of claim 39, wherein, the protrusion has four protrusion angles.

44. The threaded fastener of claim 39, wherein, the tapered interface surface is configured to form a frictional engagement with a socket of a socket configuration.

45. The threaded fastener of claim 39, wherein, at least one of the installation drive surface and the removal drive surface is configured to define a spiral having a start point spaced an initial radius from the central longitudinal axis and extending to an outer end point at a radius that is no more than 3.5 times the initial radius.

46. The threaded fastener of claim 45, wherein, no tangent to the spiral has a perpendicular line that makes an angle of less than 17° with a radius from the central longitudinal axis to a point of tangency.

47. The threaded fastener of claim 45, wherein, the spiral comprises a constant gap spiral.

48. The threaded fastener of claim 45, wherein, the spiral is defined by the equation where: θ = the rotational angle of a ray across the spiral at a distance from the axis of rotation (in radians); R i = initial radius measured from the axis of rotation to the starting point of the spiral; and R = the radius of the spiral measured from the axis of rotation at the rotational angle θ.

49. The threaded fastener of claim 45, wherein, the spiral extends from a start point to an outer end point, the radius at the outer end point being three times the initial radius.

50. The threaded fastener of claim 45, wherein, an arc of the spiral circumscribed by at least one of the installation drive surface and the removal drive surface is no more than 125°.

51. A fastener system, comprising: a socket of a socket configuration having a recess; and a fastener of a protrusion configuration having a head, a threaded shaft defining a central longitudinal axis, and a protrusion portion defining a protrusion extending axially outward from the head, the protrusion including a central portion and a plurality of protrusion angles radiating outward from the central portion, wherein: each of the protrusion angles has an installation drive surface and a removal drive surface configured to be aligned substantially parallel to the central longitudinal axis; the installation drive surface and the removal drive surface of adjacent protrusion angles are separated by a respective transition profile that forms a radially innermost portion of the protrusion angles; A wedge is formed in the transition profile to present a tapered interface surface having a top, a bottom, and a pair of opposing edges, the interface surface tapering in width from a wider width at the top of the interface surface proximate the top of the nose to a narrower width at the bottom of the interface surface proximate the bottom of the nose; and The interface surface is positioned a root radial distance from the central longitudinal axis at the bottom of the interface surface, the root radial distance defining an inner radius, the interface surface is positioned a top radial distance from the central longitudinal axis at the top of the interface surface, the top radial distance being greater than the root radial distance; wherein the threaded fastener is configured such that the recess of the socket of the screwdriver of the female configuration is able to receive the nose of the fastener of the male configuration in order to install or remove the fastener of the male configuration such that one of the installation drive surface and removal drive surface of the nose angle of the nose is engaged with the recess along an entire nose angle engagement length perpendicular to the central longitudinal axis, and such that a ratio of the nose angle engagement length to a maximum diameter of the nose perpendicular to the central longitudinal axis is 0.15 to 0.

21.

52. The fastener system of claim 51, wherein, The interface surface is configured to form a frictional engagement with the socket of the screwdriver of the female configuration at two interface regions that are separate from one another.

53. The fastener system of claim 51, wherein, The interface surface is a non-drive surface.

54. The fastener system of claim 51, wherein, The nose has six nose angles.

55. The fastener system of claim 51, wherein, The nose has four nose angles.

56. The fastener system of claim 51, wherein, At least one of the installation drive surface and removal drive surface is configured to define a spiral having a starting point spaced an initial radius from the central longitudinal axis and extending to an outer endpoint at a radius that is no more than 3.5 times the initial radius.

57. The fastener system of claim 56, wherein, A portion of the spiral lacks a tangent line whose perpendicular line to a radius from the central longitudinal axis to a point of tangency is at an angle of less than 17°.

58. The fastener system of claim 56, wherein, The spiral comprises a constant gap spiral.

59. The fastener system of claim 56, wherein, The spiral is defined by the equation where: θ = the angle of rotation (in radians) of a ray across the spiral at a distance from the axis of rotation; R i = initial radius measured from the axis of rotation to the starting point of the spiral; and R = the radius of the spiral measured from the axis of rotation at the angle of rotation θ.

60. The fastener system of claim 56, wherein, The spiral extends from a starting point to an outer endpoint, the radius at the outer endpoint being three times the initial radius.

61. The fastener system of claim 56, wherein, An arc of the spiral circumscribed by at least one of the installation drive surface and removal drive surface is no more than 125°. The interface surface is a non-drive surface. The nose has six nose angles. The nose has four nose angles. At least one of the installation drive surface and removal drive surface is configured to define a spiral having a starting point spaced an initial radius from the central longitudinal axis and extending to an outer endpoint at a radius that is no more than 3.5 times the initial radius. A portion of the spiral lacks a tangent line whose perpendicular line to a radius from the central longitudinal axis to a point of tangency is at an angle of less than 17°. The spiral comprises a constant gap spiral. The spiral is defined by the equation where: θ = the angle of rotation (in radians) of a ray across the spiral at a distance from the axis of rotation; R = the radius of the spiral measured from the axis of rotation at the angle of rotation θ. The spiral extends from a starting point to an outer endpoint, the radius at the outer endpoint being three times the initial radius. An arc of the spiral circumscribed by at least one of the installation drive surface and removal drive surface is no more than 125°.

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