US20020112524A1 - Thread roll dies - Google Patents
Thread roll dies Download PDFInfo
- Publication number
- US20020112524A1 US20020112524A1 US10/071,115 US7111502A US2002112524A1 US 20020112524 A1 US20020112524 A1 US 20020112524A1 US 7111502 A US7111502 A US 7111502A US 2002112524 A1 US2002112524 A1 US 2002112524A1
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- US
- United States
- Prior art keywords
- die
- thread
- top edge
- ridges
- thread rolling
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21H—MAKING PARTICULAR METAL OBJECTS BY ROLLING, e.g. SCREWS, WHEELS, RINGS, BARRELS, BALLS
- B21H3/00—Making helical bodies or bodies having parts of helical shape
- B21H3/02—Making helical bodies or bodies having parts of helical shape external screw-threads ; Making dies for thread rolling
- B21H3/06—Making by means of profiled members other than rolls, e.g. reciprocating flat dies or jaws, moved longitudinally or curvilinearly with respect to each other
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Extrusion Of Metal (AREA)
Abstract
Description
- This patent application claims the benefit of U.S. Provisional Application No. 60/296,626 filed Jun. 7, 2001, entitled Thread Roll Dies, Low Strain Rate, the entire contents of which are incorporated herein by reference.
- This invention relates generally to improvements in thread roll dies and more particularly to improvements in the design of roll dies that reduces scrap and produces better fasteners.
- The function of placing threads on a bolt by the use of thread rolling dies is old in the art. However, there have been important improvements in the methodology and processes over the years, particularly in the area of the thread transition zone. The thread transition zone, also known as a runout area, is the area defined by the distance from the last full thread to the beginning of the shank or grip section of the bolt. In normal bolt thread rolling practice, this length of thread dissipation is approximately 2 thread pitches long. However, in aerospace applications, the reduction in transition zone has proved very useful. Reduced transition zone is desirable because it saves weight, shortens the thread transition zone by reducing the overall thread length, and does not deteriorate the performance. U.S. Pat. Nos. 4,735,537, 4,842,466, 4,915,559, and 5,039,265 and other similar designs have been successful in reducing the thread transition runout area to well below 1 thread pitch length.
- However, the abrupt change in cross-sectional area to improve the thread transition zone has caused significant difficulties during the thread rolling process. This has especially became apparent when high strength and malleable materials such as titanium and other high strength corrosion resistant steels are used. These problems have manifested themselves by increasing frequency of laps, seams and shear bursts in the root of the thread and discontinuities.
- Therefore, it is desirable to have thread roll dies that incorporate the features of shortened thread transition length with a minimal occurrence of any unacceptable thread discrepancies. It is also desirable to have these dies produce less stress and strain rate in the thread transition area of the bolt.
- The present invention is directed at an improved thread rolling die, comprising a flat parallel longitudinal top edge and bottom edges, flat tapered die ends, and a vertical face that is used in producing the thread. Formed on the face is a series of parallel ridges which include a plurality of flanks positioned at a pre-determined angle. The ridges are complementary to the thread to be produced and are at an acute angle relative to the top and bottom edges. The ridges are configured for producing a thread helix when a blank is rolled between a set of dies.
- The die further comprises a stepped beveled surface which forms a part of the top edge located between the top edge surface of the die and the vertical face; the beveled surface is positioned at a pre-determined angle relative to the top edge surface. The ridges that intersect the stepped beveled surface have ends, that are positioned at a pre-determined angle to the top edge of the die and extend to the stepped beveled surface. The ends blend smoothly into substantially flat surfaces which extend to the top edge surface of the die such that the substantially flat surfaces are positioned at an angle less than 60 degrees from the face of the die. The ends of the improved die lead away at a 60 degree angle from the top edge of the die and are approximately at a 30 degree angle from the top edge of the die.
- The new design embodying the present invention minimizes the negative effects and still continues to reduce the distance of a dimensionally full thread acceptably close to the grip section. This feature is accomplished by changing the fabrication of the thread roll dies by having the flat narrow surfaces at an angle of less than 60 degrees from the vertical face of the die, rather than being perpendicular to the longitudinal axes of the ridges of the prior art. The improvement in the design further includes the top edge of the die leading to the ends of the vertical face of the die and leading away from at a 60 degree angle from the top surface of the die. Additionally, the improvement modifies the ends and angles it approximately 30 degrees from the perpendicular position to create smoother threads.
- In an exemplary embodiment, the stationary die and the moving die are capable of producing less stress and strain in a thread transition area of a fastener and reducing substantial scrap during the manufacture of fasteners with specific dimensions. The design not only reduces stress and strain rate in the thread transition area, but also permits a smooth engagement of a fastener blank between the stationary die and the moving die.
- Other objects, features and advantages of the invention are apparent from the following detailed description taken in connection with the accompanying drawings.
- FIG. 1 is an enlarged fragmentary perspective view of a prior art movable die depicted in U.S. Pat. No. 4,735,5637;
- FIG. 2 is an exemplary embodiment of an elevational view of a thread rolling stationary die made in accordance with the present invention;
- FIG. 2a is an enlarged perspective view of the thread rolling die;
- FIGS. 2b and 2 c are yet other enlarged perspective views of the thread rolling die depicting various features of the thread rolling die;
- FIG. 3 is a top view of the stationary die shown in FIG. 2;
- FIG. 4 is a side view of the stationary die shown in FIG. 2;
- FIG. 5 is an enlarged fragmentary elevational view of a selected
portion 184 of the stationary die shown in FIG. 2; - FIG. 6 provides other related dimensions for the stationary die for various threads per inch fasteners;
- FIG. 7 is an exemplary embodiment of an elevational view of a thread rolling moving die made in accordance with the present invention;
- FIG. 8 is a plan view of the thread rolling die shown in FIG. 7;
- FIG. 9 is a side view of the thread rolling die shown in FIG. 7;
- FIG. 10 is yet another elevational view of the moving die, respectively;
- FIG. 11 is yet another side view of the moving die;
- FIG. 12 is an enlarged fragmentary view illustrating a typical contour of a corner edge of the moving die; and
- FIG. 13 provides exemplary various dimensions of the stationary die and the moving die and their corresponding face lengths, heights and taper lengths to manufacture the stationary and the moving die.
- The prior art disclosed in U.S. Pat. No. 4,735,5637 is incorporated herein by reference. Illustrated in FIG. 1 (identified as FIGS.5 in U.S. Pat. No. 4,735,5637) is an enlarged fragmentary perspective view of a movable die 46. The
movable die 46 is identical in configuration to a stationary die (not shown). The die 46 includes flat parallel longitudinal top andbottom edges 53 and 54, and avertical face 55 which is used in producing the thread. Formed on theface 55 is a series ofparallel ridges 56 which are complementary to the thread to be produced, and therefore generally V-shaped in end elevation. In accordance with standard practice, these ridges includeflanks ridges 56 are at an acute angle relative to the top andbottom edges 53 and 54, appropriate for producing a thread helix when a screw blank is rolled between the dies. - Between the
top edge surface 53 of the die and theface 55 is a stepped,beveled surface 59 which forms a part of the upper die edge. This surface is at an angle of 25 degrees relative to thetop edge surface 53. Accordingly, the steppedbeveled surface 59 is at only a 5 degree differential with respect to the upwardly-facingflanks 57 of theridges 56 that run out at thebeveled surface 59. In practice, thebeveled surface 59 is made to blend with theflanks 57 that it intersects. The vertical dimension of thebeveled surface 59 should be equal to at least twice the pitch of the thread to be produced in order to assure adequate clearance as the thread is formed. - The
ridges 56 that intersect the steppedbeveled surface 59 have relatively abrupt ends 60. As a result, theridges 56 have their full cross-sectional dimension, symmetrical on either side of their longitudinal axes, at a location close to where they terminate. The only runout of the ridges is provided by the transverse rounded ends 60, which are generally symmetrical about the ridge axes. Preferably, this runout does not exceed one-fourth of the circumference of the thread to be produced at its pitch diameter. - The rounded ends60 of the
ridges 58 that extend to thesurface 59 blend smoothly into flat,narrow surfaces 61 which extend to thetop edge 53 surface of the die. This results in the stepped configuration of thebeveled surface 59, dividing it into segments, each of which connects to theflank 57 of one of theridges 56. The narrow surfaces 61 are transverse with respect to theridges 56, and are perpendicular to the longitudinal axes of the ridges. - The spacing between the ridge ends60 is set such that there is an increase in height from one to the next from the
die end 62, where the thread rolling begins, to the opposite end 63. - As illustrated in FIG. 1 above, the thread runout as it exits the top of the die as very abrupt and the termination of the thread in the runout (thread transition zone) area is short and quickly terminated. While this feature is desirable to achieve a minimum distance of a dimensionally full thread as close as possible to the grip or shank section, it does often create undesirable shear bursts, laps, seams and other discontinuities.
- FIGS. 2 and 7 are exemplary embodiments of elevational views of a thread rolling
stationary die 90 and a thread rolling moving die 100 respectively made in accordance with the present invention. The dies of this invention are operated as conventional dies, with the one die 90 being moved longitudinally relative to theother die 100. A screw blank is positioned between the dies to produce the screw. - FIGS. 3 through 6 and8 through 12 depict various different sectional views of the
stationary die 90 and the movingdie 100. FIG. 13, in particular, identifies various dimensions of thestationary die 90 and the moving die 100 and their corresponding face lengths, heights and taper lengths to manufacture the stationary and the moving die. The dimensions shown in FIG. 13 are exemplary only, and changes and modifications can be made therein which are within the full intended scope of the invention as herein described and claimed. - Referring back to FIG. 2, the thread rolling
stationary die 90 has a flat parallel longitudinal top edge andbottom edge pre-determined angle 116 at both ends of the die. The taper die ends 112 and 114 are tapered relatively at a same angle with reference to a central axis 115 thereby forming a trapezoid shape of the die in conjunction with thevertical face 118 and another vertical parallel face (not shown). In an exemplary embodiment, thepre-determined angle 116 is approximately 10 degree. The die 90 also includes avertical face 118 that is used in producing the thread.Radii 119 is tangent at “Y” and “L” shown in FIG. 2 to help produce a fastener with a low strain rate. In an exemplary embodiment, dies 90 and 100 are produced from a flat die material having a strength of A.I.S.I. M42. The die material is heat treated and stress relieved. - As described above, FIG. 2 is an elevational view of the thread rolling
stationary die 90. FIG. 3 is a top view and FIG. 4 is a side elevational view of thestationary die 90. Typical dimensions of thestationary die 90 for various different machine sizes are summarized in FIG. 13. For example, for amachine size 10, thestationary die 90 includes the longitudinaltop edge 102 having a length (F) of 4.250 inch and thelongitudinal bottom edge 104 having a base length (G) of 4.360 inch. The longitudinaltop edge 102 and thelongitudinal bottom edge 104 are substantially parallel. As shown in FIG. 3, thedie 90 also includes thevertical face 118 having a face width (J) of 1.500 inch, which has pre-determined number ofridges 120 complementary to the thread to be produced. Thevertical face 118 has a tapered length (K) of approximately 1.700 inch, and another tapered length (L) of 0.600 inch to permit a smooth engagement and disengagement of a fastener between thestationary die 90 and the movingdie 100. The die 90 also has the couple of taper ends 112 and 114 having a height (H) of 0.625 inch respectively. FIG. 6 provides other related dimensions for thestationary die 90 which includes various taper depth dimensions identified as “V”, “W”, and “Y” in FIG. 2. FIG. 13 also providesexemplary dimensions 230 for the moving die 100 and thestationary die 90 formachine sizes - FIG. 2a is an enlarged perspective view of the
thread rolling die 90. As shown in FIG. 2a, formed on theface 118 is a series ofparallel ridges 120. Theridges 120 include a plurality offlanks ridges 120 are complementary to the thread to be produced. The ridges are at an acute angle relative to the top andbottom edges stationary die 90, shown in FIG. 2 and the movingdie 100, shown in FIG. 7. A steppedbeveled surface 144, which forms a part of the upper die edge, is located between thetop edge surface 102 of the die and thevertical face 118. Thebeveled surface 144 is positioned at a pre-determined angle relative to thetop edge surface 102. Theridges beveled surface 144 have ends 160, which are positioned at a 60 degree angle to thetop edge surface 102 of the die. Additionally, theends 160 extend to the steppedbeveled surface 144 and blend smoothly into thesurfaces 162 which extend to thetop edge surface 102 of the die such that thesurfaces 162 are positioned at an angle less than 60 degrees from thevertical face 118 of the die. - FIGS. 2b and 2 c are yet other enlarged perspective views of the thread rolling die 90 depicting the stepped
beveled surface 144 having ends 160. As shown in FIGS. 2b and 2 c, theends 162 are positioned at a 60 degree angle to the top of thedie 102. Additionally, theends 160 extend to the steppedbeveled surface 144 and blend smoothly into thesurfaces 162 which extend to thetop edge surface 102 of the die such that thesurfaces 162 are positioned at an angle less than 60 degrees from theface 118 of the die. Thesurfaces 162 are transverse with respect to theridges 120, being at approximately a 60 degree angle to the longitudinal axes of theridges 120. - FIG. 3 is an exemplary embodiment of a
top view 170 of thestationary die 100 in accordance with the present invention.Top view 170 displays thevertical face 118 of the die in addition to the flat tapered die ends 112 and 114 with aface width 172 of the die at both the ends. In an exemplary embodiment, a length ofnotch 174 at a start end of both dies 90 and 100 is of a pre-determined length to ensure smooth engagement and disengagement between the dies and a blank. - FIG. 4 is an
end view 180 of thestationary die 90. Theend view 180 shows aheight 182 of thestationary die 90. FIG. 5 is an enlarged fragmentary elevational view of aportion 184 of thestationary die 90, shown in FIG. 2. Theportion 184 shows an enlarged view of ataper depth 188. Thetaper depth dimension 164 for thestationary die 90 are the same as thetaper depth dimension 165 of the moving die 100 for a given size of the fastener. Exemplary dimensions of the typical tapereddepths depth 166 in relation to threads perinch 167 produced by various dies are shown in FIG. 6. Additionally, the enlarged view shown in FIG. 5 depicts that the ends 160 extend to the steppedbeveled surface 144 and blend smoothly into thesurfaces 162 which extend to thetop edge surface 102 of the die such that thesurfaces 162 are positioned at apre-determined angle 186. In an exemplary embodiment, thepre-determined angle 186 is an approximate angle of 30 degrees. - FIG. 7 is an exemplary embodiment of an elevational view of the thread rolling moving die100 made in accordance with the present invention. FIG. 8 is a top view and FIG. 9 is a side view of the moving
die 100. Typical dimensions of the moving die 100 for various different machine sizes are summarized in FIG. 13. For example, for amachine size 10, the moving die 100 includes a longitudinaltop edge 202 having a length (A) of 5.000 inches and alongitudinal bottom edge 204 having a base length (B) of 5.110 inches. The longitudinaltop edge 202 and thelongitudinal bottom edge 204 are substantially parallel. As shown in FIG. 8, thedie 100 also includes avertical face 218 having a face length (D) of 1.500 inches, which has pre-determined number ofridges 220 complementary to the thread to be produced. Thevertical face 218 has a tapered length (E) of approximately 4.000 inches to permit a smooth engagement and disengagement of a fastener between the moving die 100 and thestationary die 90. Thedie 100 also has a couple of taper ends 224 and 226 each having a height (C) of 0.625 inch. FIG. 13 providesexemplary dimensions 230 for the moving die 100 and thestationary die 90 formachine sizes - FIGS. 10 and 11 are yet other elevational and side views of the moving
die 100. Although, the detail discussions relate to moving die 100, the principles underlying these discussions are equally applicable tostationary die 90. As illustrated in FIG. 7 above, thedie 100 has a couple of taper ends 224 and 226. The taper ends 224 and 226 are tapered approximately 10 degrees towards acentral axis 240 of the die. The tapered ends 224 and 226 provide smooth engagement and disengagement with the fastener. - FIG. 12 is an enlarged fragmentary view illustrating a typical contour of a corner edge of the die. FIG. 12 also exemplifies the configuration of the
ridges 120. Theridges 120 that intersect the stepped beveled surface 144 (shown in FIG. 2a) have relatively smooth ends 160 which preferably are convexly rounded with compound curvature. As a result, theridges 120 have their full cross-sectional dimension, symmetrical on either side of their longitudinal axes, at a location close to where they terminate. The only runout of the ridges is provided by the transverse rounded ends 160, which are generally symmetrical about the ridge axes. As illustrated in FIG. 12, the 15 degree angle applies from the beginning of notch and radius along the root radius until it runs out at the edge of the die. - The new design embodying the present invention and described in FIGS. 2 through 13 minimizes the negative effects and still continues to reduce the distance of a dimensionally full thread acceptably close to the grip section. This feature is accomplished by changing the fabrication of the thread roll dies by having the
faces 162 at an angle of less than 60 degrees from thevertical face 118 of the die, rather than being perpendicular (as shown in FIG. 1) to the longitudinal axes of the ridges of the prior art. Additionally, the prior art depicts a radius 60 (shown in FIG. 1) as the thread transitions from thevertical face 118 of the die to the 90 degree angle with sharp corners on the top thread leading toradius 60 and leavingradius 60 on top of the die. The improvement in the design not only radiuses at this point (which is designated as a referenced numeral 160 in FIGS. 2a, 2 b, and 2 c), but also thetop edge 102 leading to theends 160 of theface 118 of the die and leading away at a 60 degree angle from thetop surface 102 of the die. - The prior art further illustrates that the face60 (shown in FIG. 1) is leading away from the
face 55 of die (shown in FIG. 1) and is perpendicular to the flat surface 53 (shown in FIG. 1) of the top of the die. On the other hand, the improvement modifies thesurface 160 and angles it approximately 30 degrees from the perpendicular position. This arrangement is exemplified in FIGS. 2, 2a, 2 b, and 2 c above. These differences result in major improvements in reducing scrap and at the same time produce a much better product by avoiding abrupt changes in cross-sectional areas in the manufacturing of dies. - While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.
Claims (19)
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/071,115 US20020112524A1 (en) | 2001-02-16 | 2002-02-07 | Thread roll dies |
TW91112221A TW561078B (en) | 2001-06-07 | 2002-06-06 | Improved thread roll dies |
PCT/US2002/017886 WO2002100570A1 (en) | 2001-06-07 | 2002-06-07 | Improved thread roll dies |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US26962601P | 2001-02-16 | 2001-02-16 | |
US10/071,115 US20020112524A1 (en) | 2001-02-16 | 2002-02-07 | Thread roll dies |
Publications (1)
Publication Number | Publication Date |
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US20020112524A1 true US20020112524A1 (en) | 2002-08-22 |
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ID=26751850
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US10/071,115 Abandoned US20020112524A1 (en) | 2001-02-16 | 2002-02-07 | Thread roll dies |
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US (1) | US20020112524A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20130051954A1 (en) * | 2010-07-14 | 2013-02-28 | Illinois Tool Works, Inc. | Thread forming die and method |
US9757792B1 (en) * | 2014-04-09 | 2017-09-12 | Mark Doll | Method for making a die for roll forming a dual threaded bolt |
-
2002
- 2002-02-07 US US10/071,115 patent/US20020112524A1/en not_active Abandoned
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20130051954A1 (en) * | 2010-07-14 | 2013-02-28 | Illinois Tool Works, Inc. | Thread forming die and method |
US9511414B2 (en) * | 2010-07-14 | 2016-12-06 | Illinois Tool Works Inc. | Thread forming die and method |
US9757792B1 (en) * | 2014-04-09 | 2017-09-12 | Mark Doll | Method for making a die for roll forming a dual threaded bolt |
US10232427B1 (en) * | 2014-04-09 | 2019-03-19 | Mark Doll | Method for making a die for roll forming a dual threaded bolt |
US10315244B1 (en) * | 2014-04-09 | 2019-06-11 | Mark Doll | Method of forming a die for roll forming a dual threaded bolt |
US10350670B1 (en) * | 2014-04-09 | 2019-07-16 | Mark Doll | Method for making a dual threaded bolt roll forming die |
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AS | Assignment |
Owner name: FAIRCHILD HOLDING CORP., VIRGINIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:CATON, MICHAEL R.;CENICEROS, MARCELINO;REEL/FRAME:012582/0351 Effective date: 20020118 Owner name: FAIRCHILD HOLDING CORP., VIRGINIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:WALTON-RUNYON, MICHELE;RUNYON, LISA M. ON BEHALF OF MICHAEL L. RUNYON;REEL/FRAME:012582/0338;SIGNING DATES FROM 20020130 TO 20020202 |
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AS | Assignment |
Owner name: HUCK PATENTS, INC., DELAWARE Free format text: RESUBMISSION OF RECORDATION NO. 700021280A TO CORRECT EXECUTION DATE FROM NOV. 8, 2002 TO DEC. 3, 2002.;ASSIGNOR:FAIRCHILD HOLDING CORP.;REEL/FRAME:013315/0264 Effective date: 20021203 |
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STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |