RU2774791C1 - Shortened fastener with locally adjustable thread height - Google Patents

Abstract

FIELD: mounting hardware.

SUBSTANCE: invention relates to threaded fasteners. An external threaded fastener with protection against screwing with a deflection comprises an essentially round rod having a front end, an end to which torque is applied, and a set of external threads running around the circumference of the rod. In this case, the set of threads contains: a standard thread passing around at least part of the circumference of the rod and having a contour of the standard thread, in which the width and angle of elevation of the standard thread provide the possibility of engagement with the corresponding internal threads, in which the outer diameter of the standard thread is between the lower limit of the outer diameter and the upper limit of the outer diameter; a transition thread passing around at least part of the circumference of the rod and having a transition thread contour with a width and angle of elevation similar to the width and angle of elevation of a standard thread, which makes it possible to engage with the corresponding internal threads; a thread protecting against screwing with a deflection, passing around at least part of the circumference of the rod and having a thread contour protecting against screwing with a deflection and an outer diameter configured to align a fastener with an external thread with protection against screwing with a deflection relative to a fastener with an internal thread; and an initial engagement thread passing around at least the measure of the part of the circumference of the rod and having the contour of the thread of the initial engagement. The contour of the transition thread has a height that goes from the lower limit of the outer diameter of the standard thread to the outer diameter of the thread that protects against screwing with a deflection.

EFFECT: as a result, a short fastening element has been created that has protection against screwing with a deflection.

20 cl, 35 dwg

Description

Field of invention

The present invention relates per se to threaded fasteners such as screws and bolts, and more particularly to thread transitions at the leading end of a helical thread line.

Prerequisites

US Pat. No. 5,836,731 discloses an anti-twist fastener and this document is incorporated herein in its entirety. In FIG. 1 is a side view of a prior art anti-twist fastener in which the helical thread line differs from most fastener threads in that the helical line has four successive contours instead of the standard thread contour over the entire length of the helix. The four loops are (listed from the head of the fastener to its front end): (i) a loop of 10 standard ISO threads that runs around the fastener shank on most of the turns of the helix, and the number of turns is determined by the need to achieve the required functional thread length; (ii) a transition thread contour 20 adjacent to the standard contour; (iii) an anti-tightening loop 30 having a radius profile as described in US Pat. spiral and whose task is to direct the spiral of the thread into conjugation with the mating internal thread. US Pat. No. 9,644,664, which is incorporated herein in its entirety, describes the contour of the initial engagement coils 40 which improves the protection of the fastener against skewed screwing. US Pat. No. 6,561,741, incorporated herein in its entirety, describes an initial engagement loop 40 that improves initial engagement to align a fastener. The contour 40 turns of the initial engagement may also have other, less ideal profiles. Fasteners with skew and counterfeit protection are available on the market under the trade names MAThread® and MATpoint®.

The transition thread contour 20 has two main functions: (i) to form a smooth transition between the ISO standard thread contour 10 and the anti-skew contour 30, and (ii) not to interfere with or make improper contact with the female thread during make-up. Both of these features are non-structural and do not require standard full height threads.

To perform the first function, the transition thread contour 20 has one end that blends into the contour 10 of the ISO standard thread and the other end that blends smoothly into the radial profile of the anti-tightening contour 30. The height of the anti-twist contour 30 is approximately half the height of a standard ISO thread contour 10. The transition thread contour 20 should provide a smooth transition between these thread heights.

To perform the second function, the transitional thread contour 20 has a height decreasing along its length. In FIG. 2 shows a cross-section of two adjacent fastener threads along the longitudinal axis of the fastener shaft 14. These threads have standard parts. For example, an ISO standard thread contour 10 has cavities 11, flanks 12, and a crest 13, wherein the angle of the flanks 12 is approximately sixty degrees. The flanks 12 are flat and extend from the troughs 11 to the apex 13. The ISO standard thread contour 10 is the highest thread contour with an outside diameter of 16 standard threads. The anti-twist contour 30 has a height of approximately half the height, having an outer diameter of 36, so there is a difference of 62 between the heights of the threads. with a contour of 40 turns of initial engagement and with a contour of 30, which protects against screwing with a misalignment.

In FIG. 3A-3H show a sequence of sections of the contour 20 of the transition thread, when this thread wraps around the shaft 14 of the fastener. In these drawings, a straight line 61 passes through the vertices of the contour thread 20 to illustrate the constant decrease in height as the helix of the thread wraps around the shaft 14. The contour 20 of the thread transition blends or merges with the contour 10 of the standard ISO thread (see Fig. 3A) and anti-twisting profile 30 (see FIG. 3H). As the height of the standard section 21 of the transition thread contour 20 decreases, more and more of the anti-torsion section 22 protrudes to form the flanks 12 in the cavities 11. The transition thread contour 20 first appears as a slightly shorter standard thread profile. (See Fig. 3B), where the flanks 12 are at the same angles, and the width of the top 13 is the same as in the contour 10 of the ISO standard thread. The difference is that this profile is shifted down, so the thread becomes shorter and the width between the valleys 11 is narrower. In FIG. The 3D section 21 of the standard thread is shifted further downwards so that the contour 20 of the transition thread becomes even shorter. In addition, with the standard section 21 pushed down, the anti-tightening section 22 is inflated to form side surfaces adjacent to the recesses 11. In FIG. 3E, the standard section 21 is moved further downwards so that the transition thread contour 20 becomes even shorter and the anti-skew section 22 forms an even greater part of the flanks 12 adjacent to the cavities 11. In FIG. 3F, the anti-torque portion 22 dominates, while the standard portion 21 forms a apex at the top of the transition thread contour 20. In FIG. 3F, the transition thread contour 20 is similar to that shown in FIG. 3G, except that the top of the standard portion 21 protruding from the top of the anti-torque portion 22 becomes even shorter and narrower. Importantly, as shown in FIG. 3B-3G that the top 13 on the top of the standard section 21 maintains the same width and the side surfaces 12 of the standard section 21 maintain their angles of inclination.

In FIG. 4A-4H show a sequence of sections of another known transitional thread contour 20 as it wraps around the fastener shaft 14. Instead of shifting the standard section 21 down, the transition thread contour 20 increases the angles of the flanks 12 of the standard section 21. The transition thread contour 20 first appears as a slightly shorter standard thread profile (FIG. 4B), where the width of the tip 13 is equal to the width in the standard thread contour 11 ISO, but the side surfaces 12 are angled slightly wider so as to extend up to the depressions 11. In FIG. 4C-4E, the thread transition contour 20 is shortened by keeping the width of the crest 13 the same, and the wider slope of the flanks 12 extending up to the troughs 11. In FIG. 4F, the height of the transition thread contour 20 continues to shorten so that the anti-tightening section 22 bulges out to form flanks at the cavities 11 and the flanks 12 of the standard section 21 expand to merge into the contour of the anti-tightening section 22. In FIG. 4G, the anti-twist portion 22 dominates, with only a small protrusion with a apex 13 at the top, the very wide side surfaces 12 merge into the anti-twist contour 22.

Known transition thread contours 20 to effect such a transition vary between the superimposed contours shown in FIG. 3B-3G and the more smoothly transitioning contours shown in FIG. 4B-4G. Any shape between these contours is adequate to perform the transition function.

The second function of the transition thread contour, i.e. prevent collision with female threads in use, can be done with a thread height that is never so high over the length of the thread that it can collide with and/or seize the female threads of the female fastener during runout of the male fastener anti-twist element. Decreasing the height at a substantially linear rate as the helix progresses from the full height of the thread to the anti-torsion thread gives satisfactory results. For example, a M8×1.5g metric adapter thread was used with a constant height reduction rate of approx. 0.0015 mm per degree of helix rotation. In FIG. 3A-3H and 4A-4H, a straight 61 passes through the crests of the via thread contour 20 to illustrate the constant decrease in height as the helix wraps around the shank 14. The via thread contour 20 was used from a quarter turn (90 degrees) to one and a quarter turn. (450 degrees).

Brief description of the invention

Thus, there is a need for an improved anti-twist fastener.

According to aspects of the present invention, there is provided an anti-twist male threaded fastener, comprising: a substantially circular shank having a front end and a torque end, and a plurality of external threads extending around the circumference of the shank, wherein a plurality external threads contains: a standard thread around at least part of the circumference of the rod and having the contour of a standard thread, and the width and angle of the standard thread provide the possibility of engagement with the corresponding internal thread, and the outer diameter of the standard thread is between the lower limit of the outer diameter and the upper limit of the outer diameter ; a transition thread around at least a portion of the circumference of the shaft and having a transition thread contour with a width and lead angle similar to the width and lead angle of a standard thread, which allows engagement with the corresponding internal thread; an anti-torque thread extending around at least a portion of the circumference of the stem and having an anti-torque thread contour and an outer diameter configured to help align the male anti-torque fastener relative to the fastener with internal thread; and an initial engagement thread around at least a portion of the circumference of the shank and having an initial engagement thread contour, wherein the adapter thread contour has a height that transitions from the lower limit of the outside diameter of the standard thread to the outside diameter of the anti-skew thread.

According to another aspect of the present invention, there is provided an anti-skew male threaded fastener, comprising: a substantially circular shank having a front end, an end to which a torque is applied, and a plurality of external threads extending around the circumference of the shank, wherein a plurality external threads contains: a standard thread around at least part of the circumference of the rod and having a standard thread contour defined by troughs, a flat top and flat flanks extending from the troughs to the top, and a thread helix equal to approx. sixty degrees, and the outer diameter of the standard thread is between the lower limit of the outer diameter and the upper limit of the outer diameter; a transition thread that forms a continuous helix with a standard thread around at least a portion of the circumference of the shank and contains a contour of the transition thread defined by troughs, a flat top, and flat side surfaces extending from the troughs to the top and with a helix angle of approx. sixty degrees; an anti-torque thread that forms a continuous helix with a transition thread around at least a portion of the circumference of the shank and has an anti-torque thread contour and an outside diameter configured to assist in alignment of a male anti-torque fastener skewed relative to the fastener with internal thread; and an initial engagement thread forming a continuous helix with anti-twist threads around at least a portion of the circumference of the shaft and having an initial engagement thread contour, wherein the apex of the contour of the transition thread expands and the height of the transition thread decreases as the contour of the transition thread The thread contour changes from the contour of a standard thread to the contour of a thread protecting against misalignment.

According to still another aspect of the present invention, there is provided an anti-skew male threaded fastener comprising: a substantially circular shank having a front end, an end to which a torque is applied, and a plurality of external threads comprising: a standard thread around a at least part of the shank circumference and having a standard thread contour defined by the troughs at the minimum diameter, the flat top at the outside diameter, and the flat flanks extending from the troughs to the flat top, having a width at the mean thread diameter, and a lead angle of approximately sixty degrees , and the outer diameter of the standard thread is between the lower limit of the outer diameter and the upper limit of the outer diameter; a transition thread forming a continuous spiral with a standard thread around at least a portion of the circumference of the rod and containing the contour of the transition thread, defined by troughs, a flat top and flat side surfaces extending from the troughs to the top, and a lead angle of approximately sixty degrees, and a height, not exceeding the lower limit of the outer diameter of the standard thread contour, and the adapter thread extends less than about five-eighths of a turn (255 degrees) around the shaft; and an anti-torque thread forming a continuous helix with a transition thread around at least a portion of the circumference of the shank and having an anti-torque thread contour having an outer diameter approximately equal to the mean diameter of a standard thread, wherein the contour of the anti-torque thread screwing with a misalignment, has a shape defined by a curve extending from the curve in the cavity to approximately the outer diameter.

Brief description of the drawings

A more complete understanding of the present invention gives the following description in conjunction with the attached drawings, where:

Fig. 1 is a side view of a known male fastener with skew protection.

Fig. 2 is a cross-sectional view of the standard and anti-torque threads of the male anti-torque fastener shown in FIG. one.

Fig. 3A-3H are a series of successive sections of the contour of the transition thread as it progresses around the fastener shank from the standard thread to the anti-skew thread.

Fig. 4A-4H are a series of successive sections of the contour of the transition thread as it progresses around the fastener shank from the standard thread to the anti-skew thread.

Fig. 5 is a longitudinal section of a thread rolling die and a fastener with anti-twisting threads machined in the thread rolling die.

Fig. 6 - section of a cutter for cutting grooves for thread rolling in a thread rolling die.

Fig. 7A is a sectional view of an ISO standard thread outline of a grooved thread rolling die.

Fig. 7B is a sectional view of the contour of a transition thread being rolled into a groove of a thread rolling die.

Fig. 8A and 8B are an end view and a side view, respectively, of a prior art anti-skew threaded fastener having a long transition thread.

Fig. 9 is a cross-sectional view of the transition thread contour according to the present invention.

Fig. 10 is a cross-sectional view of three fastener threads rolled in three adjacent grooves of a thread rolling die to form a standard thread whose outside diameter is at the upper limit of the outside diameter.

Fig. 11A and 11B are end and side views of a male anti-torsion threaded fastener of the present invention.

Fig. 12A and 12B are end and side views of a male anti-torsion threaded fastener of the present invention.

Fig. 13A-13D are sectional views of the transitional threads taken at the positions shown in FIG. 13E.

Fig. 13E is an end cut view of a male fastener on a transition thread contour.

While the present invention may be subject to various changes and may take various alternative forms, the drawings show and describe in detail specific illustrative embodiments. It should be understood, however, that the foregoing description of these specific illustrative embodiments does not limit the present invention to the specific forms described, but the invention embraces all modifications and equivalents as defined in the appended claims.

Detailed description

According to the idea of the present invention, it is possible to create shorter fasteners that retain thread engagement and anti-twist functionality.

Aspects of the present invention address the issue of a "fixed" length contour of a transition thread on a thread helix on an anti-twist fastener. Also related to aspects of the present invention is a method of reducing the length of the contour of a transition thread on a thread helix on an anti-torque fastener while maintaining the full functionality of the anti-torque.

The contour length of the thread transition was previously considered "fixed", since the height transition can ideally be achieved at the calculated length of the thread helix. In practice, the length of the transition thread contour is greater than the calculated ideal length, since it is impossible to obtain this ideal length using modern production and manufacturing methods. This anomaly is caused by two circumstances; 1) the application of the thread rolling die itself must have its own tolerances, and 2) the use of a process that must take into account thread height tolerances.

Because of these limitations, the groove in the thread rolling die that is used to form the contour of the transition thread on the thread helix must be longer and deeper than necessary to form the required length of helical taper on the fastener. This extra groove length in the die requires additional "space" in the die, which is wasted because it is not used to achieve the desired change in the contour height of the adapter thread that the die rolls during thread rolling. As such, a longer than necessary linear transition in the die results in a longer helical transition formed on the helix of the fastener.

A thread rolling die for an anti-skew fastener can be formed using a standard thread mill and cutting a series of linear grooves into the surface of the thread rolling die. When each individual cutter reaches a certain point, its cutting surface retracts from the workpiece (die) at a constant speed as the cutter continues to move in a straight line across the surface of the die. The groove cut in this way in the surface of the die is linear at a constant depth over a finite length, then slopes upwards and exits the die. The angle thus formed at the bottom of the groove, due to the retraction of the cutter, is consistent with the growth rate desired for the contour of the transition thread formed in the helix of the fastener that this die will roll. The growth rate of the transition thread contour is shown in Fig. 3A-3H and 4A-4H by line 61 passing through the tops of the thread sections. The ideal linear angle at the bottom of the die groove results in a transition thread contour that is approximately three-quarters of a turn (270 degrees) of a helix in length when knurled on the fastener.

The slant portion of the grooves in the die that forms the contour of the threaded adapter must, in fact, be longer and deeper than the calculated ideal length of the contour of the threaded thread due to the tolerances of the thread rolling die itself and the thread height tolerances. With longer and deeper grooves in the die, these grooves are not completely filled with metal when forming the thread tip at their deepest points, and the grooves are narrower than standard full threads over the entire lead length in the die. These factors contribute to the formation of a transition thread contour that does not have thread flanks at the same width and fullness as a standard thread. In particular, over the entire length of the rise in the groove of the die, the helical line of the contour of the transitional thread, knurled on the fastener by the contour of the die, is technically not capable of engaging with the side surfaces of the standard internal thread. Even though the required change in height can be obtained on the required three-quarter turn (270 degrees) of the helix, the contour of the transition thread continues for some distance beyond this length as full height threads, but with narrower flanks than full standard threads. Because the main purpose of a transition thread is to create a transition from the height of a standard ISO thread to the height of the anti-skew thread, the contour of the transition thread has some area along its length where a change in height is not required.

The drawings show details of exemplary embodiments. The same elements in the drawings are represented by the same reference numbers.

In FIG. 5 shows a cross-sectional side view of a thread rolling die 60 and a fastener 50 with anti-twist protection. The cross section is drawn through the center of the thread rolling groove 63 in the thread rolling die 60. To illustrate the alignment between the die 60 and the helix of the fastener that it rolls, the anti-skew fastener 50 is shown with the thread helix "straightened" so that the linear the groove of the die, and the normally curved thread helix are shown as a linear rise rather than the curved helix that is actually seen in a fastener that has been machined with such a die. The thread rolling groove 63 has a constant depth portion 64 and a ramp 65. The thread rolling groove 63 transitions from the constant depth portion 64 to the ramp 65 at transition point 66, and the ramp 65 ends at an end point (not shown) at an intersection with the slot of the thread profile. , protecting against screwing with a warp. The constant depth portion 64 of the thread rolling groove 63 forms the outline of a standard ISO thread on the anti-twist fastener 50 . The inclined section 65 of the thread-rolling groove 63 defines the contour 20 of the transition thread on the fastener 50 with anti-skew protection. The length of the ramp 65 extends past the point where the apex reaches the maximum height 16 of the standard thread. This lost groove length 68 is "lost" because it is not filled with metal during knurling, leaving a gap 69. Therefore, the lost groove length 68 serves no other role than providing a tolerance space for forming over-thread threads.

In FIG. 6 shows a side sectional view of a cutter 70 for cutting a thread rolling groove 63 in a die 60. In order for the cutter 70 to be used to cut a portion 64 of constant depth in the thread rolling groove 63 of a die 60 as shown in FIG. 5, it should have a longer tip compared to a cutter designed for cutting nominal threads, which would have a shorter tip 72. Further, when the cutter 70 is gradually fed to cut the slant portion 65, the cutter 70 is too thin to cut the groove 63 in a die 60 wide enough to form a full width ISO standard thread contour 10 until its cutting edge reaches its maximum depth in the die where it cuts a constant depth section 64. Thus, the entire slant portion 65 of the groove 63 is cut by the cutter 71, which is too narrow to form a full width ISO standard thread outline 10.

In FIG. 7A is a side sectional view of the contour 10 of an ISO standard thread being rolled by a die 60. FIG. 7B is a side sectional view of the contour 20 of the transition thread being rolled by the die 60. To illustrate, the profile 17 of the standard thread in FIG. 7B superimposed on the plate. In comparison, the standard section 21 of the transition thread contour 20 formed in the transition region of the die 60 is narrower on the flanks than the standard thread profile 17. In fact, this means that the length of the effective area of the die, reserved for the growth of the adapter thread to its peak height, is lost when the discrete part of the adapter thread is rolled, the peak height 16 of which is actually in the allowable range of standard thread tip heights, but since the profile is too narrow, this area does not function as a full thread. There is thus a length of thread helix rolled by the die 60 between the slant of the thread transition contour and the point where the thread reaches its full height and width, which is only present through the use of known means of manufacture. This length of the die via is not needed to lift the via because the thread crest reaches the required height to meet the minimum height requirement for a standard thread in the first part of the flute, and the last region of the via only forms the contour of the via that is above the minimum required height and too narrow to be considered a full thread.

In FIG. 8A and 8B show end and side views, respectively, of a prior art anti-skew male threaded fastener 50 having a long transition thread contour 20 . The helix ISO standard thread contour 10 has its full width and height up to the first change point 23 where the transition thread contour 02 begins. The helix thread transition contour 20 has a first portion 24 located between the change point 23 and the second change point 25, where the thread profile has a height above the minimum required for a full standard thread, but a width too small to work as a full standard thread. At the second change point 25, the height of the transition thread contour 20 is reduced to the average height of the standard thread. In the second section 26, the helix profile decreases in height, reaching the minimum height of the standard thread at change point 27, but still too narrow to work as a full standard thread. Starting from the third change point 27, the transition thread contour 20 begins to shorten in height. In the third section 28, the height and width of the transition thread contour 20 are constantly reduced to the fourth change point 29. The fourth change point 29 designates the end of the transition thread contour 20 and the start of the thread contour 30 protecting against skewed screwing. It should be noted that the anti-torque portion 22 of the anti-traverse thread contour 30 demonstrates that the adapter thread contour 20 is too thin to function as a full standard thread over its entire length, including the first portion 24. Prior to the present invention anti-skew fasteners had a transition thread contour 20 of this length and contained a "too narrow" first helix section 24.

In some embodiments of the present invention, this "too narrow" length of transition thread loop 20 can be eliminated to provide a shorter anti-skew fastener. In order to obtain the shortest possible full-function male fastener with protection against misaligned screwing, i.e. of the least expensive, shortest, lightest and most packable fastener, this "too narrow" length of the transition thread contour 20 can be eliminated. The design of an anti-skew male threaded fastener can be based on a method of limiting the length of the adapter thread actually needed to gradually rise to the minimum acceptable crest height without a useless "too narrow" section. Some embodiments of the present invention include a new contour for use on part of the helix of male threaded fasteners with anti-skew protection, which allows the length of the adapter thread to be shortened without adversely affecting the function of the thread.

In some embodiments, the present invention provides a new transition thread contour for male threaded fasteners with anti-skew protection that eliminates excess non-functional helix length from that portion of the thread helix. Such improvements can be achieved by reconfiguring the first and second portions 24 and 26 of the helix thread transition contour 20 shown in FIG. 8A and 8B.

These two sections of the transition helix are modified by reshaping each helix length into a full standard width contra thread. Full width helix sections should have a new, variable, yet more tightly controlled peak height. In particular, the peak height is entirely within the acceptable peak height range of a standard thread. In accordance with aspects of the present invention, peak height values are deliberately reduced in a controlled manner over the combined length of the thread helix of the two sections, the first and second sections 24 and 26, to the minimum acceptable standard thread profile height, at the second change point 25 where the second section 26 transitions into the start of a new one, shorter transition thread.

By reconfiguring these portions of the helix, the thread effectively becomes a "standard thread" so that the combined length of the first and second portions 24, 26 can be added to the helix of the existing standard thread, allowing for a longer structural helix with a standard contour, and a shorter section of the helix, performing only the function of the transition. This allows you to get shorter fasteners that perform the same functions.

In accordance with aspects of the present invention, applied to a male anti-twist fastener described here, the length of the adapter thread can be approximately a quarter of a turn (90 degrees) less than a known perfect thread, while still maintaining sink rate functionality. known transitional thread. Even a small reduction in the length of the non-structural helix of the fastener can provide great benefits in the functioning of the fastener. Therefore, various aspects of the present invention can provide a shorter, lighter, less expensive, better packable fastener with improved anti-skew protection.

In FIG. 9 shows a cross-sectional side view of a thread transition contour 120 of the present invention. The adapter thread contour 120 has a thread height 118 that is significantly shorter than the possible height of the outer diameter 116 of a standard thread. The outer diameter 116 of a standard thread can be formed by completely filling the die in a middle position adequate to fulfill the requirements of the standard thread. Contour thread contour 120 having a relatively lower thread height 118 retains all of the characteristics of a standard thread except for the height. Because the height 118 of the thread contour 120 is more tightly controlled, these threads do not need to be maintained within the same significant tolerance range and can be shorter to reduce the localized peak height to a more valuable height while maintaining the full width and flank angles to ensure fastening performance. This relatively reduced thread height 118 may allow the helix thread transition contour 120 to start at a lower height.

This highly localized intentional reduction in the peak height of the thread, assuming it is only localized and the rest of the standard thread helix remains at full height and to full tolerances, still gives the manufacturer the freedom to change the peak height of the standard thread everywhere except for this reprofiled section of the transition thread, as may be required by the manufacturer's processes and/or customer requirements.

According to aspects of the present invention, thread rolling dies are provided for standard threads with anti-skew protection with a reduced depth area in the dies groove, which preferably always fills completely. FIG. 10 is a cross-sectional side view of three threads of a fastener 150 being rolled in three adjacent grooves of a die 160 to form a standard thread whose outer diameter is at the upper limit 115 of the outer diameter. In the first groove, the fastener thread material is pressed into a shorter, more restrictive groove to completely fill the groove to a more restricted thread profile whose height is at the lower limit 116 of the outside diameter. In the second groove, the thread material of the fastener is pressed into a full depth groove to partially fill the groove up to an average OD limit of 114. In the third groove, the fastener thread material is pressed into a full depth groove to fill the groove up to the upper limit of 115 outer diameter having the maximum allowable height. During the thread rolling process, the metal flow is restricted to a discrete portion of the helix, allowing the rest of the full thread helix to varying degrees not to completely fill the groove within the allowable height range, i.e., between the lower limit 116 of the outer diameter and the upper limit 115 of the outer diameter to meet individual manufacturer's requirements for the overall height of a standard thread having an outside diameter, without in any way affecting the rolling process or the function of the structural thread. This preferential filling of the reshaped bottom profile portion can occur even when an adjacent full standard thread helix is produced with a peak at the lower limit 116 of the outside diameter.

Aspects of the present invention provide an intentional, localized reduction in thread height in the region adjacent to the adapter thread, which can shorten the "lift" required to reach the peak of an anti-skew male fastener to create an effectively shorter adapter thread and reduce length. fasteners with anti-twisting protection. A portion of the thread helix on an anti-skew male fastener of the type described above may be contoured to shorten the effective thread helix length of such a fastener. The transitional thread helix may not exceed one turn (360 degrees) in length, may begin at the end of the standard helix of the fastener at the point where the standard turns are furthest from the head of the fastener, and may terminate on the anti-screw thread with skewed.

The contour of the transition thread according to aspects of the present invention may be such that its highest point merges with a standard full-height thread of the helix. From here, the contour of the helix thread transition can decrease in height at a given rate as it wraps around the fastener shaft to its shortest point. The contour of the adapter thread begins at the point where the outside diameter of the nominal full helix height of the standard thread first decreases in height and merges by approximately a quarter turn (90 degrees) of the helix, continuing to reduce the height of the thread but keeping the flanks the same as the standard thread. threads. During peak height reduction, the thread transition contour retains the flank width and thread angle in accordance with the standard thread profile while having a height approximately equal to the minimum allowable for a full standard thread, defined as the outer diameter lower limit 116 .

The section of the full standard thread of the helix can thus acquire a length similar to a functionally equivalent thread, and the transition section of the helix can thus be reduced in length by an equivalent amount. An anti-torque male fastener may have a corresponding anti-torque thread adjacent to the front end of the adapter thread, as well as a corresponding initial engagement thread, as well as appropriate guides on the top of the fastener. It is expected that this design can also be applied to other types of fasteners, as well as anti-skew male threaded fasteners that have a shorter, i.e., less than ideal lead thread length, to improve their performance.

In FIG. 11A and 11B are end and side views of an anti-tight screw male fastener of the present invention. The helix ISO standard thread outline 110 has the full width and height of the standard thread up to the first change point 123 . At the first change point 123, the thread helix has the average height of the standard thread, the full width of the flanks of the standard thread, and a helix angle of sixty degrees (see 115 in FIG. 10). This width of the side surfaces and the height of the top is maintained throughout the first section 124 to the second change point 125. In the second section 126 from the second change point 125 to the third change point 127, the profile of the spiral line is constantly decreasing in height 118 at a predetermined rate, to the average limit 114 of the outer diameter for the height of the standard thread (minimum allowable) (see 114 in Fig. 10 ) at the third change point 127. Throughout the second section 126, the width of the side surfaces is maintained as the profile of a standard fastener. As shown in FIG. 11B, the top of the thread throughout the second section 126 becomes wider from the second change point 125 to the third change point 127. Also, as shown in FIG. 11B, the flat thread flanks throughout the second portion 126 remain in the valleys from the second change point 125 to the third change point 127.

Further, as shown in FIG. 11A and 11B, the third section 128 extends from the third change point 127 to the fourth change point 129. At the third change point 127, the thread contour is the contour of the standard thread 110 reduced to its minimum height and maintaining the standard width of the flanks. The transition thread contour 120 starts with this profile at the third change point 127 and continues with the transition until it becomes the anti-skew thread profile at the fourth change point 129. The thread transition path 120 may begin at a third change point 127 and end at a fourth change point 129 such that it extends about five-eighths of a turn (255 degrees) around the shank 14.

In FIG. 12A and 12B show end and side views, respectively, of an anti-skew male threaded fastener. In this embodiment, the thread of the fastener has the maximum state of the material, which means that the thread vertices are located the highest relative to the pitch line and the groove in the die that forms such a vertex will be completely filled with material. A notable difference between this variant and the variant shown in FIG. 11A and 11B is that the full thread height is at the limited lower maximum allowable height (see 116 in FIG. 10) at the first change point 123 on the thread helix, and not at the greater height of the standard thread (see 115 in FIG. Fig. 10). In the limited, maximum state of the material, the tip would, as one would expect, flow down to the maximum allowable height in the groove of the thread rolling die. But the thread tip is instead deliberately controlled to be shorter than the expected flow height, and this controlled height is reduced at a constant preferred rate to the average tip height while maintaining the full width of the flanks. This difference in thread tolerances and manufacturing results in a constant rise in the helix section in the third section 128 rather than a constant decrease in height in the first section 124 (see FIG. 11A). This change in height demonstrates the "free flow" of metal up to this height in a fastener using an extreme outside diameter.

As a comparison of the drawings (FIGS. 11A-11B and 12A-12B) shows, the length of the effective full standard thread is increased by reconfiguring the first section 124 and the second section 126 to be full width threads, with the overall length of the helix of the fastener is saved.

In FIG. 13E is a sectional end view of a male fastener on a transition thread contour, and FIG. 13A-13D are side views of the cross-sectional threads shown in FIG. 13E. Contour 120 thread has the same width as the profile of the standard thread, but gradually decreasing top height from the maximum allowable to the minimum allowable for the standard thread. As shown in FIG. 13A-13D, the width of the transition thread contour 120 remains constant and equal to the width of the standard thread profile. As shown in FIG. 13D, the transition thread contour 120 is at its height 118 coinciding with the outer diameter upper limit 115. See 115 in FIG. 10. As shown in FIG. 13C, the transition thread contour 120 is shorter, having a height 118 that does not reach the maximum allowable for the standard thread 115. As shown in FIG. 13B, the transition thread contour 120 is shorter while still having a height 118 not as short as the average outside diameter limit 114 for the standard length. See 114 in FIG. 10. As shown in FIG. 13A, the transition thread contour 120 has a height 118 approximately equal to the minimum allowable for a full standard thread, defined as the lower limit 116 of the male thread. See 116 in FIG. ten.

Because the transition thread contour 120 has flanks of the same width as the standard thread, the length of the ISO standard thread portion of the helix can be shortened. In particular, it can be shortened by the length of the transition thread contour 120 from the first change point 123 to the third change point 127. This section of thread transition contour 120 replaces a previously functionally unnecessary section, allowing it to now be considered a standard thread, adding useful length to the standard thread helix. Therefore, an additional full thread can now be added to the joint design, or alternatively, the overall length of the reduced standard thread fastener can be reduced by the amount of added low profile standard thread, which reduces weight and cost.

The thread transition contour 120 of the present invention can be produced as part of the thread helix of an anti-skew male fastener by intentionally creating a reduced diameter region of the fastener blank on the thread rolling die, creating a specific localized thread rolling die region that is not completely filled with metal during knurling time to allow the metal to flow freely to obtain the desired shape. Alternatively, the transition thread loop 120 can be made with a reduced height in some localized region of the helix. Any of these methods allows you to create a section of a helix with a full width and reduced height.

Although embodiments of the present invention have been shown, described and defined by reference to illustrative embodiments of the invention, such references are not intended to limit the invention and such limitations should not be imposed. The disclosed subject matter is capable of significant changes, modifications and substitutions in form and function that are obvious to those skilled in the art and take advantage of the present invention. The embodiments of the present invention shown and described are merely examples and do not exhaust the scope of the present invention.

Claims (36)

1. A fastener with an external thread with protection against screwing with misalignment, containing: a substantially round rod having a front end, an end to which a torque is applied, and a plurality of external threads extending around the circumference of the rod, the plurality of threads comprising: a standard thread extending around at least a portion of the circumference of the shank and having a standard thread contour, wherein the width and pitch of the standard thread enable engagement with the corresponding internal threads, the outside diameter of the standard thread being between the lower limit of the outer diameter and the upper limit of the outer diameter; a transition thread extending around at least a portion of the circumference of the shank and having a transition thread contour with a width and lead angle similar to the width and lead angle of a standard thread, which enables engagement with corresponding internal threads; an anti-torque thread extending around at least a portion of the circumference of the shank and having an anti-torque thread contour and an outer diameter configured to help align the male anti-torque fastener with respect to the fastener with internal thread; and an initial engagement thread extending around at least a portion of the shank circumference and having an initial engagement thread contour, moreover, the contour of the transition thread has a height that goes from the lower limit of the outer diameter of the standard thread to the outer diameter of the anti-skew thread. 2. Fastener according to claim 1, wherein the standard thread has at least two turns (720 degrees) around the shaft. 3. The fastener of claim 1 wherein the adapter thread has less than five-eighths of a turn (255 degrees) around the shank. 4. The fastener of claim 1, wherein the anti-twisting thread has one turn (360 degrees) to two turns (720 degrees) around the shaft. 5. A fastener according to claim 1, wherein the initial engagement thread has from half a turn (180 degrees) to two turns (720 degrees) around the shank. 6. The fastener of claim 1, wherein the standard thread has a helix angle of approximately sixty degrees, and the transition thread has a helix angle of approximately sixty degrees from root to tip. 7. Fastener according to claim. 1, in which the contour of the transition thread has a vertex that expands as the height changes from the lower limit of the outer diameter of the standard thread to the outer diameter of the thread that protects against screwing with misalignment. 8. The fastener according to claim 1, wherein the outer diameter of the anti-torque thread is approximately equal to the average diameter of the standard thread, while the contour of the anti-torque thread has a shape defined by a curve extending from the curve in the cavity approximately outside diameter. 9. The fastener of claim 1, wherein the standard thread, transition thread, anti-skew thread, and initial engagement thread comprise a continuous thread helix extending around the shank. 10. Fastener according to claim. 1, additionally containing a guide top at the front end of the rod. 11. The fastener according to claim 10, wherein the driver tip has a variable outer diameter and length, with the variable outer diameter being maximum at the front end of the rod and decreasing towards the end of the driver tip remote from the front end of the rod. 12. A fastener with an external thread with protection against screwing with a misalignment, containing: a substantially circular rod having a front end, an end to which a torque is applied, and a plurality of external threads extending around the circumference of the rod, wherein the plurality of external threads comprises: a standard thread extending around at least a portion of the circumference of the shank and having a standard thread contour defined by the troughs, a flat top, and flat flanks extending from the troughs to the top, and a helix angle of approximately sixty degrees, the outside diameter of the standard thread being between the lower limit of the outer diameter and the upper limit of the outer diameter; a transition thread forming a continuous helix with standard threads, passing around at least a portion of the circumference of the rod and having a transition thread contour defined by troughs, a flat top and flat side surfaces extending from the troughs to the top, and a lead angle of approximately sixty degrees; an anti-torsion thread forming a continuous helix with a transitional thread extending around at least a portion of the circumference of the shank and having an anti-torque thread contour and an outer diameter configured to help align the male fastener with protection against screwing with distortion relative to the fastener with an internal thread; and an initial engagement thread forming a continuous helix with a thread protecting against misaligned screwing, passing around at least a part of the shank circumference and having an initial engagement thread contour, moreover, the apex of the contour of the transition thread expands, and the height of the contour of the transition thread decreases as the contour of the transition thread passes from the contour of the standard thread to the contour of the thread that protects against screwing with misalignment. 13. The fastener of claim 12, wherein the adapter thread has less than about five-eighths of a turn (255 degrees) around the shank. 14. The fastener according to claim 12, wherein the outer diameter of the anti-torque thread is approximately equal to the average diameter of the standard thread, and the contour of the anti-torque thread has a shape defined by a curve extending from the curve to the trough of approximately to outer diameter. 15. The fastener of claim 12, wherein the standard thread, transition thread, anti-skew thread, and initial engagement thread comprise a continuous thread helix around the shank. 16. Fastener according to claim 12, further comprising a guide top at the front end of the rod. 17. The fastener according to claim 16, wherein the driver apex comprises a variable outer diameter and length, wherein the variable outer diameter is maximum at the front end of the rod and decreases towards the end of the driver vertex distant from the front end of the rod. 18. A fastener with an external thread with protection against screwing with a misalignment, comprising: a substantially circular rod having a front end, an end to which a torque is applied, and a plurality of external threads extending around the circumference of the rod, wherein the plurality of external threads comprises: a standard thread extending around at least a portion of the circumference of the shank and having a standard thread contour defined by troughs on the minimum diameter, a flat top on the outer diameter, and flat lateral surfaces extending from the troughs to the top and having a width on the average diameter, and a thread helix, equal to approximately sixty degrees, and the outer diameter of the standard thread is between the lower limit of the outer diameter and the upper limit of the outer diameter; a transition thread forming a continuous helix with a standard thread, passing around at least part of the circumference of the rod and having a transition thread contour defined by troughs, a flat top and flat side surfaces extending from the troughs to the top, and a lead angle of approximately sixty degrees, and a height not exceeding the lower limit of the outside diameter of the standard thread contour, wherein the adapter thread has less than about five-eighths of a turn (255 degrees) around the shank; and an anti-torsion thread forming a continuous helix with a transitional thread extending around at least a portion of the circumference of the shank and having an anti-torque thread contour having an outer diameter approximately equal to the mean diameter of a standard thread, wherein the thread contour, anti-twisted, has a shape defined by a curve extending from the curve in the cavity to approximately the outer diameter. 19. The fastener according to claim 18, further comprising an initial engagement thread forming a continuous helix with threads protecting against misaligned screwing, passing at least part of the circumference of the rod and having an initial engagement thread contour. 20. Fastener according to claim 18, further comprising a guide top at the front end of the rod.

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