ROLL DIE

Abstract

A roll die for use with a thread roiling apparatus for roll forming threads on a part is disclosed. The roll die generally comprises a stationary roll die having a first predetermined thread on one surface thereof. The roll die also comprises a moving roll die having a second predetermined thread on a first predetermined portion of a surface thereof and a third predetermined thread on a second predetermined portion of the surface of the moving roll die. The moving roll die also includes at least one ramp arranged between a second predetermined thread and a third predetermined thread. The roll die may be capable of roll forming multiple threads on a fastener or threaded blank or part in a single pass.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a roll die, and more particularly relates to a flat roll die for use in a thread roller for rolling threads on a fastener or other threaded part.

2. Description of Related Art

Thread rolling machines have been known for many years in the art. Some prior art thread rolling machines have a movable die that is reciprocated back and forth relative to a stationary die in order to form threads on the shanks of fasteners or blanks Which are fed one at a time between the dies. Generally, the blanks are stored in a supply hopper and are fed from the hopper to the dies along a track defined by a pair of parallel rails. The blanks are held in the track. by an upper hold down rail based above the parallel rails. Generally, in each blank enters an injection position adjacent to the dies and a pressure or finger feeds the blank between the dies. Many of these thread rolling machines of the prior art are capable of forming threads of many different types and sizes on blanks. When the blank or work piece is placed between the dies the stroke of the reciprocating and movable die may allow for the work piece or part to be rolled along the die faces and the work piece material is displaced to form the required thread thereon.

Some prior art thread rolling machines are also capable of roll forming multiple threads on a fastener or threaded part. Generally, this takes multiple passes to have multiple threads arranged on the threaded part. The prior art also has thread roll forming machines that are capable of rolling multiple threads On a fastener but have to use multiple piece roll dies in order to create the multiple threads on a threaded part or fastener. Hence, the die change over to replace the die to a second die or to have more than one die arranged in the machine increases the cost and time necessary to manufacture multi-threaded fasteners. Therefore, there is a need in the art for an improved flat roll die that may roll form multiple threads on a fastener or threaded part in a single pass.

There also is a need in the art for a roll die, made from a single piece of steel, that is capable of roll forming multiple threads on a fastener. Furthermore, there is a need in the art for an improved roll die that utilizes roll on and off ramps between a fine and coarse thread intersection on a single surface or face of a moving roll die. There also is a need in the art for an improved flat roll die that may allow for an intersection between fine and coarse threads that may not damage the part being rolled or cause slipping of the part due to an abrupt mismatch between the overlap of two different thread types. There also is a need in the art for a flat roll die that is capable of roll forming multiple threads on a fastener that is more efficient and may allow for increased manufacturing capacities with less down time of the machinery at a lower cost.

SUMMARY OF THE INVENTION

One object of the present invention may be to provide an Unproved flat roll die.

Another object of the present invention may be to provide a roll die that is capable of roll forming multiple threads on a fastener or threaded part in a single pass through the die.

Still another object of the present invention may he to provide a roll die that is designed front a single piece of material, such as steel.

Still another object of the present invention may be to provide a roll die that utilizes roll on and off ramps between a fine and coarse thread intersection on a surface or face of the roll die.

Still another object of the present invention may be to provide a roll die that allows for an intersection between a fine and a coarse thread that may not damage the part being rolled.

Still another object of the present invention may be to provide a roll die that does not cause slipping of the part due to an abrupt mismatch between the overlap of two different size threads.

Still another object of the present invention may be to provide a roll die that increases efficiency and reduces down time of the machinery thus reducing costs and increasing profit for the manufacturer.

According to the present invention, the foregoing and other objects and advantages are obtained by a novel design for a roll die. The roll die, which is for use in a thread rolling apparatus for roll forming threads on a part, comprises a stationary roll die having a first predetermined thread on a surface thereof. The roll die further comprises a moving roll die having a second predetermined thread on a first predetermined portion of the surface thereof and a third predetermined thread on a second predetermined portion of the surface of the moving roll die. The roll die also comprises at least one ramp arranged between a second predetermined thread and a third predetermined thread on the moving roll die. A single roll die may allow for roll forming of multiple threads on a fastener or threaded part in a single pass.

One advantage of the present invention may be that it provides an improved flat roll die.

A further advantage of the present invention may be that it provides for a roll die apparatus that may roll form multiple threads on a fastener in a single pass.

Still a further advantage of the present invention may be that it provides for a roll die that is designed from a single piece of material, such as but not limited to a steel.

Still another advantage of the present invention may be that it provides a roll die that utilizes roll on and off ramps between first and second thread intersections.

Still another advantage of the present invention may be that it provides for a roll die that allows an intersection between a fine and a coarse thread to not damage the part being rolled therebetween.

Still another advantage of the present invention may be that it provides for a roll die that does not generally allowing slipping of a part being rolled due to an abrupt mismatch between the overlap of two different threads therebetween.

Yet another advantage of the present invention may be that it provides for a roll die that reduces the cost while, increasing the efficiency of threading multiple threads on a fastener in a roll die thread roller apparatus or machine.

Yet another advantage of the present invention may be that it provides for a roll die that may increase the number of parts being manufactured in a predetermined time frame compared to parts being manufactured by a prior art roll die in the same time frame.

Other objects, features and advantages of the present invention may become apparent from the subsequent description and appended claims, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a side view of a stationary die according to the present invention.

FIG. 2 shows a side view of a moving die according to the present invention.

FIG. 3 shows a close up of an intersection between a first and second thread of a moving die according to the present invention.

FIG. 4 shows a top view of a moving die according to the present invention.

FIG. 5 shows a flat die thread roller machine having a roll die according to the present invention installed therein.

FIG. 6 shows a blank and dual threaded fastener according to the present invention.

BRIEF DESCRIPTION OF THE EMBODIMENTS

Referring to the drawings, there is shown a roll die 10 according to an embodiment of the present invention. Generally, the present invention is a roll die 10 that is a flat roll die that may roll form multiple threads on a fastener, blank or threaded part in a single pass. The prior art roll dies generally had to use multiple passes to roll form multiple threads on a fastener or threaded. part and also had to use multiple piece roll dies to perform such multi thread rolling. The roll die 10 of the present invention is a die that is designed from a single piece of material. In one contemplated embodiment the material is a steel, however any other metal, ceramic, plastic, composite or natural material may also be used to form the roll die 10 of the present invention. The roll die 10 of the present invention may utilize in its single piece construction roll on and off ramps 12 between a fine 14 and coarse thread 15 intersection. These ramps 12 may allow the intersections between the fine 14 and coarse threads 16 to not damage the part being rolled form therebetween or cause slipping of the part due to an abrupt mismatch between the overlap 12 of the two different thread sizes.

Generally, the roll die 10 of the present invention is a flat roll die 10. However, it is also contemplated that it may he used on a rotary die which is used in conjunction with a stationary shoe or any other type of die known to be capable of roll forming threads onto a fastener, blank or part. Generally, the roll die 10 of the present invention. may use any known thread combination specified by the customer. Generally, the thread form is designed. and tailored to the multi thread. fastener or part being manufactured by the customer. Hence, the thread form may be specified in inch series or metric series and may be tailored and designed by using key properties of the part being roiled. Some of these properties are as follows, the blank diameter, the pitch diameter the major diameter, the root radii, the crest radii, and the flank angles are all properties that may be used when designing thread forms for a flat roll die 10 according to the present invention. It should further be noted that the roll die 10 of the present invention may also use custom tailored helix angles when creating the multi thread roll dies 10. The helix angles generally are calculated by using customer provided information, such as the pitch diameter, the thread form depth, the root radii depth, the crest radii, and the major diameter of the finished rolled part. All of these calculations may he used in determining the helix intervals required of the multi thread roll dies 10 of the present invention, It should further be noted that the helix angle may be verified and inspected on the die faces with a helix angle inspection plate.

Generally, the flat roll die 10 of the present invention may be used in any known fiat die thread roller machine 18 in the prior art. One contemplated thread roller 18 for use with the present invention may include a feed hopper that orients and feeds blanks or work pieces 20 into a feed chute 22 and then a pressure injector 24 which is operating in a timed relationship to the moving the 26, may inject, a blank or work piece 20 between the dies at the start end of the moving die 26. In the roll die 10, the threads are rolled onto the blank 20 by moving or reciprocating, the moving the 26 with relation to a stationary roll die 28. The roll forming machine 18 generally has a base or body member 17 upon which is mounted a flat base plate. Generally, the stationary roll die 28 of the present invention is supported and fixed in position relative to the base plate, while the movable or reciprocating die 26 is supported for a back and forth reciprocation or notion relative, to the stationary die 28 by a guide shoe, which is mounted on the base plate which receives a sliding die holder therein. A feeder system may feed the blanks 20 to the start edge of the moving die 26 and stationary die 28 and may allow for the blank 20 to be passed through the moving rod die 26 and stationary die 28 in a single path, thus rolling, a multi thread configuration onto the blank 20 at the desired configuration requested by the customer. It should be noted that any other type or setup of a flat die thread roller machine 18 may be used, not just that one described herein.

The flat roll die 10 of the present invention generally includes a stationary roll die 10 and a moving or reciprocating roll die 26 arranger adjacent to one another with a predetermined distance arranged therebetween. The distance arranged therebetween may be capable of being adjusted based on the diameter of the blank 20 being rolled therethrough. Generally, the stationary roll die 28 may be made of a steel material, however any other metal, ceramic, composite, or natural material may be used for the stationary roll die 28. The stationary roll die 28 generally may have a rectangular shape when viewed from a top surface thereof. The stationary roll die 28 may be manufactured via any known manufacturing technique, such as but not limited to grinding, milling, electrical discharge machine, etc. In one contemplated embodiment the stationary roll die 28 may be manufactured with only coarse threads 16. It should be noted that the coarse thread 16 is put onto the stationary die 28 using properties that pertain to its form and function. Furthermore, the coarse threads 16 are put onto the stationary die 28 using a central location wherein the central location is verified by using a helix inspection gage. The central location of the coarse threads 16 is crucial in form and function between, the moving die 26 and the stationary die 28. The central location generally is a center point or a mid. point of the die face 30 having the threads 16 thereon. The center point 32 may allow for the stationary die 28 to be flipped in the shoe holding the stationary die 28 in the thread rolling machine 18 and still allow for threads 16 to be rolled onto a blank 20 in the proper orientation to the blank 20 being rolled. Hence, the center or mid point 30 of the stationary die 28 is identified and the threads 16 are manufactured onto the face 30 about or around the center point 32 to allow for proper alignment of the coarse threads 16 on the stationary roll die 28. It should be noted that any type of thread, such as any coarse threads 16, any fine threads 14, or any extra fine threads may be used on the stationary die 28 of the present invention. Generally, coarse threads 16 are defined as any type of thread that has between eight and sixty four threads per inch depending on the major diameter of the blank 20 being used. A fine thread 14 is generally defined as any type of thread having between twelve and eighty threads per inch depending on the major diameter of the blank 20 being used. Furthermore, extra fine thread is generally defined as having between twenty and thirty two threads per inch depending on the major. diameter of the blank 20 being used. Therefore, in the present invention generally a coarse thread 16 is the only thread arranged on the working face 30 of the stationary roll die 28. It should be noted that both ends of the stationary die 28 also may include angled surfaces 40 to allow for adjustments of the stationary die 28 with relation to the base 17 of the roll thread roller machine 18. This may allow for inserts or shims to be placed therein thus allowing the stationary roll die face 30 to be at a proper position with relation to the blank 20 being rolled and the moving roll die 26 of the present invention. Therefore, an type of stationary die 28 using any of the parameters as discussed above and using any type of coarse thread 16 using the parameters discussed above may be placed and arranged on the face 30 of the stationary roll die 28. It should be noted that coarse threads 16 may be arranged on the face 30 parallel to one another and set at a predetermined angle on the face 30.

The roll die 18 of the present also includes a moving or reciprocating roll die 26 that is designed to place multiple threads on a blank 20 being rolled thereon. The moving roll die 26 may be manufactured through any known technique, such as but not limited to grinding, milling, electrical discharge machine, or any other type of manufacturing technique capable of placing the threads 14 on the working die face 34 of the moving roll die 26. Generally, the moving roll die 26 is also made of a steel material, however any other metal, ceramic, plastic, composite, or natural material may also be used for the moving roll die 26. The moving rolling die 26 of the present invention generally is manufactured with both coarse 16 and fine threads 14 on the die face 34. The orientation of the fine 14 and coarse threads 16 is crucial in deciding the form and function of the finished rolled pan. Generally, a helix angle of both coarse 16 and fine thread 14 are calculated using information received from the customer. This information generally includes, but is not limited, to, the pitch diameter, the thread form depth, the root radii, the crest radii, and the major diameter of the finished rolled part. Generally, both the moving die 26 and the stationary die 28 may or may not have a starting end 36 and a finishing, end 38, The start end 36 of the moving roll die 26 generally utilizes the coarse thread 16 only. This coarse thread 16 may extend a predetermined distance towards the opposite end or finishing end 38 of the moving roll die 26. The coarse thread 18 arranged at the start end 36 of the moving roll die 26 may have a predetermined length. This length may generally he calculated using the following formula: blank diameter×(Pi)×(2.75) will equal the length of the coarse thread 16 start portion of the moving die 26. It should further be noted that this coarse thread 16 may also be centralized in accordance to the helical angle of the coarse thread 16 on the stationary roll die 28. This may allow for the centralization of the coarse thread 16 on the moving die 26 to match the centralization of the coarse thread 16 on the stationary roll die 28. The same type of centralization calculation may be performed as described above wherein the mid point of the moving roll die 26 or the mid point of the coarse threads 16 of the moving roll die 26 may be identified and the coarse threads 16 manufactured onto the working face 34 of the moving roll die 26, based on the central or mid point location on the die face 34. This may allow for the moving die 26 to he flipped over and still apply the coarse threads 16 in unison with the coarse threads 16 on the stationary die 26.

The other portion of the working face 34 of the moving roll die 26 may have a fine thread 14 arranged thereon. The length of the fine thread 14 on the moving roll die 26 may be dedicated to the remaining amount of moving roll die face 34 not occupied by the coarse threads 16. Hence, whatever has not been formed with coarse threads 16 may be formed with the fine threads 14 according to the present invention. However, it Should be noted that any other type of relationship between the coarse threads 16 and fine threads 14 may also occur other than just the coarse threads 16 being followed by fine threads 14, such as but not limited to coarse threads 16 followed by fine threads 14 followed by coarse threads 16, etc. It should further be noted that the coarse threads 16 on the moving die 26 and the coarse threads 16 on the stationary die 28 may or may not be the same. The relationship between the fine 14 and coarse threads 16 is crucial to the ability to have multi threads rolled onto the blank 20. It should be noted that the fine thread 14 must also be centralized to the coarse thread 16 in a general relationship of pitch to pitch function. Furthermore, the coarse 16 and fine threads 14 must have radii depths that have the exact same depth planes because failure to achieve this exact same depth plane may cause a pitch diameter under or oversized failure in the fine thread 14 with relation to the coarse thread 16 on the finished roiled part. It should further be noted that the crest radii depth between the coarse 16 and fine 14 thread may have a different plane depth due to the difference in the pitch diameters of the fine 14 and coarse threads 16. Furthermore, the fine 14 and coarse threads 16 have an overlap at a predetermined area wherein the overlap having a predetermined length that is determined through overlap of both the fine 14 and coarse threads 16 having different helical angles. This overlap is adjustable through pullout of the tool being used for the thread manufacturing. It should he noted that this overlap length is crucial as the overlap may dictate the length of the On ramp and off ramps 12 which create the transition from the fine 14 to coarse threads 16 on the moving roll die 26. It should be noted that the length of the overlap may be calculated to let the root radii of the fine 14 and coarse thread 16 to overlap each other such that no voids occur between each root radius. Therefore, it should be noted that generally at least one ramp 12 is arranged between each of the fine 14 and coarse threads 16. In one contemplated embodiment the ramp 12 is located between each generally parallel but offset fine 14 and coarse thread 16. It should be noted that the ramp 12 generally may be made in either a radial or flat style or shape. The ramp 12 may allow for an easy transition between the fine 14 and coarse threads 16 for the part being rolled. It should further be noted that the ramp length on both the fine 14 and coarse threads 16 may be calculated using the blank diameter and the pitch diameter. The ramps 12 on the fine 14 and coarse threads 16 generally are ground, milled or for formed with an electrical discharge machine, such as that found in a five axis machine. It should be noted that the ramps 12 may have any known width and angle or ascent or decent from either the fine thread 14 or the coarse thread 16 on the working face 34 of the moving die 26.

It should be noted that the fine thread 14 form may be specified by the customer and that the form depth and helix angle are all calculated according to the pitch diameter needed and diameter of the part being rolled. The same may apply for the coarse thread 16 and may be any form as specified by a customer. In one contemplated embodiment, the coarse thread 16 may be offset a predetermined distance from the fine thread 14 on the face 34 of the moving die 26. This may allow the fine thread 14 to align with and create a fine thread on the crest of the coarse thread of the blank 20. This may allow a power nut to be arranged over the coarse thread portion of a multi-thread bolt and a lock not to be arranged and interact with a fine thread portion of a multi thread bolt, thus allowing for a mechanically locked bolt and nut apparatus.

It should also be noted that the stationary die 28 and moving die 26 may have any known length, width, and thickness. In one contemplated embodiment, each of the dies have a length of approximately seven inches, a width of approximately three inches and a depth of approximately one and a half inches. However, any other known dimensions may be used for both the moving die 26 and the stationary die 28. It should also be noted that it is also contemplated to use a ramp 12 at both the start end 36 and the finish end 38 of the stationary die 28 and the moving die 26. it is also contemplated to use the angled surfaces 40 on each end of the moving die 26, such as those described above for the stationary die 28. These angled surfaces 40 on the end may help to properly align both the moving die 26 and the stationary die 28 with relation to the blank or part 20 being passed therethrough.

In operation, the roll die 10 of the present invention may be mounted as a single piece flat roll die 10 to a thread rolling machine 18. The part 20 may be inserted into the flat toll die 10 between a stationary die 28 and a moving die 20, which moves and reciprocates with relation to the stationary die 28 thus roll forming multiple threads into the part 20 in a single pass through the flat roll die 10. The moving die 26 may then return back to its starting position and the next blank or part 20 to be threaded may be arranged therebetween and the process will repeat with the moving roll die 26 moving in a linear direction with relation to the stationary die 28, rolling the blank 20 along the threads of both the stationary die 28 and the moving die 26, thus roll forming threads having a predetermined parameters as discussed above onto the blank 20. The resulting dual threaded fasteners 42 may be capable of being used with a coarse nut and/or a fine nut to create a mechanically locked bolt and nut assembly that is resistant to loosening from vibration. The blanks 20 generally are fed from a storage hopper along a transfer line to a position where the blank 20 contacts both the start end of the stationary die 28 and the start end of the moving die 26. It should be noted that any other known rolling technique, such as those described above, may also be used in conjunction with the moving die 26 and stationary die 28 as described herein. It should further be noted that any combination of threads may be used on the moving die 26 or any type of thread may be also be used on the stationary die 28.

The present invention has been described in an illustrative manner. It is to be understood that the terminology which has been used is intended to he in a nature of words of description. rather than that of limitation.

Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described.

Claims

1. A roll die for use with a thread rolling apparatus for roll forming threads or a part, said roll die comprising:

a stationary roll die having first predetermined threads on one surface thereof;

a moving roll die having second predetermined threads on a first predetermined portion of a surface thereof;

said moving roll die having third predetermined threads on a second predetermined portion of said surface of said moving roll die; and

at least one ramp arranged between one of said second predetermined threads and one of said third predetermined threads.

2. The roll die of claim 1 wherein said stationary roll die and said moving roll die are flat roll dies.

3. The roll die of claim 1 Wherein said first predetermined threads are a coarse thread.

4. The roll die of claim 1 wherein said second predetermined threads are a coarse thread.

5. The roll die of claim 1 Wherein said third predetermined threads are a fine thread.

6. The roll die of claim 1 Wherein at least one ramp is generally radial of flat in shape, said ramp having a predetermined length.

7. The roll die of claim 1 further comprising a plurality of ramps.

8. The roll die of claim 1 wherein said first predetermined threads are arranged on said surface about a central location.

9. The roll die of claim 1 wherein said third predetermined threads are offset from said second predetermined threads.

10. The roll die of claim 7 wherein said offset aligns said third predetermined threads with a root of said second predetermined threads.

11. The roll die of claim 7 wherein said first predetermined threads are the same as said second predetermined threads.

12. A thread rolling apparatus for roiling threads on a fastener, said thread rolling apparatus comprising;

a body;

a die carrier secured to said body;

a reciprocal slide mounted to said body;

a stationary die having first predetermined threads on a surface thereof, said stationary die secured to said die carrier;

a moving die having second predetermined threads and third predetermined threads on different portions of a surface thereof, said moving die secured to said reciprocal slide; and

at least one ramp arranged between one of said second predetermined threads and one of said third predetermined threads.

13. A method of rolling threads on a part with a thread rolling machine, said method comprising the steps of:

mounting.; a single piece flat roll die to the thread rolling machine:

inserting the part into said flat roll die; and

roll forming multiple threads on the part in a single pass through said flat roll die.

14. The method of claim 13 wherein said flat roll die having a stationary roll die and a moving roll die.

15. The method of claim 14 wherein said stationary roll die having a coarse thread on a surface thereof.

16. The method of claim 15 wherein said moving roll die having said coarse thread on a surface thereof and a fine thread on said surface thereof.

17. A method of claim 16 wherein said moving roll die having at least one ramp arranged between said fine thread and said coarse thread.

18. The method of claim 17 wherein said at least one ramp further comprising a roll on and off ramp between said fine and said coarse thread intersections.

19. The method of claim 13 wherein said flat roll die having a thread with a predetermined helix angle thereon.

20. The method of claim 18 wherein said roll on and off ramp have a predetermined length and generally a radial or flat shape.