US1907684A

US1907684A - Thread rolling die

Info

Publication number: US1907684A
Application number: US548544A
Authority: US
Inventors: Thomson Robert
Original assignee: DARDELET THREADLOCK CORP
Current assignee: DARDELET THREADLOCK Corp
Priority date: 1931-07-03
Filing date: 1931-07-03
Publication date: 1933-05-09
Anticipated expiration: 1950-05-09

Description

May 9, 1933. R. THOMSON 1,907,684 I THREAD ROLLI NG DIE Filed July 3, 1931 *2 Sheets-Sheet l 155555 1 50006271005022 BY I ATTORNEYS May 9, 1933. R. THOMSON .THREAD ROLLING DIE Filed July 3, 1931 2 Sheets-Sheet 2 mm m0 m T fl wN 30 operation;

Patented May 9 1933 UNIT STATES RAT'ENT. OFFICE Bonner 'rnomson, or mmeron, NEW JERSEY, LssIoNoB r DARDELET Tillman Loox conronarron, 01 NEW YORK, N.'.Y., A CORPORATION or DELAWARE THREAD ROLLING DIE Application filed m a, 1931. Serial No. 548,544.

Important objects of the present invention are, to provide improved thread rolling dies designed for more accurate thread forming; to provide such dies having ribs arranged for successive engagement with the work in, a manner to obtain an equalized thread forming action throughout the rolling operation; to provide such dies designed to firmly hold the work in a manner to prevent twisting thereof during the rolling operation and consequent inaccurate thread forming; to provide such'dies designed to prevent twisting of the work by an arrangement of the ribs to obtain symmetrical distribution of the points where the thread forming action occurs, so that.twisting moments will be prevented; and to provide such dies designed for more equalized distributionof the metal displaced by the rolling operation. Other objects of the invention will appear hereinafter.

In the drawings: v Fig. 1- is a face View of one of the dies; Fig. 2- a face view of the other die;

.Fig. 3 an enlarged detail section taken on the line 33 of Fig.1 showing several of the die ridges in engagement wit-h a work piece;

Fig. 4 a' side view of the two dies upon areduced scale showin them in cooperative.

relation at the beginnlng of a thread rolling Fig. 5 is an upper edge view of the dies in said relation;'and

Figs. 6 to 13 inclusive, enlarged transverse sections taken on the correspondingly num-- bered section lines of Fig. 4 and diagrammatically showing the successive engagements of the thread forming ribs with the work.

The bodies of the dies are flat, rigid plates preferably formed of high speed steel and shaped forniounting in a standard thread rolling machine. -The die which is to be mounted in a fixed position in the machine is designated 1 and the reciprocating die is designated 2. Each has a rectangular Working face upon which there are thread forming ribs or ridges arranged to form a tapering field. In general outline the field defines a salient directed toward the leading end of the die. The ridges arenpreferably formed upon the die face by a milling operation and then the die is hardened. It is customary to operatively mount thread rolling dies in vertical planes with one longitudinal edge uppermost. "In the present instance the ridge fields are formed adjacentthe upper longitudinal edges of the dies and the working faces are flat and smooth below the fields. The .excess depth ofthe dies is merely to adapt them to their mountings in a machine.

.The dies are intended primarily for hot rolling but they may be employed for cold rolling also.

The fixed die 1 has its thread forming ridges inclined in accordance with the desired thread helix angle atone side of the work which is to be threaded.- As shown,the ridges are varied in length in a certain stepped relation forsuccessive engagement with the Work during a rolling operation. There is a single ridge 3 of maximum length near the .middle of the field. This ridge extends nearest to the leading end of the die. Above the 4, a single ridge 5, apair of ridges 6, a single ridge 7 and a pair of ridges 7 These alternating singles and pairs have their leading ends successively spaced rearward in steps ridge 3 there are in successiona pair of ridges each equal to approximately one half the circumference of the bolt shank or other work piece to be threaded. Below the ridge 3 there are in succession

single ridges

8, 9, 10- and 11. The ridge 8 has its leading edge spaced rearward from that of ridge 3 approximately one half the work circumference and the succeeding

ribs

9, 10 and 11 have their leading ends spaced rearward in steps each equal to approximately the entire circumference of the work. 7 J

The moving die 2 has its thread forming ridges inclined oppositely to those of die 1 when in working position; As shown, its ridges are also varied in length somewhat similarlyto those of die 1. There is a pair of ridges 12 of equal and maximum length near the middle of the field. Above the ridges 12 there are insuccession asingle ridge 13, a pair of ridges 14, a single ridge 15, a pair of ridges 16 and a single ridge 17. These alterridges 19 merging with the upper edge of the die. Below the ridges 12 there are in succession,

single ridges

20, 21, 22 and 23 having their leading ends spaced rearward from the endsof ridges 12 in steps each equal to aprlo proximately anentire circumference of the work piece.

In the present instance the thread forming ridges of the two dies have a cross sectional contour designed for forming a wellknown Dardelet type of thread disclosed in U. S. Patent No. 1,657,244. The ridges are materially wider than the grooves between them,

the crests of the ridges make an angle of preferably six degrees with the die faces and their side faces converge outward slightly. Such die ridges will form, upon a bolt or similar work piece, a male thread having a-groove materially wider, than itsrib and a sloping root surface adapted for self-locking coaction with a similarly sloping surface upon the crest of an engaged female thread. This selflocking coaction is obtained by relative crosswise displacement of I the engaged threads upon relative turning of the threaded memberswithout axial advance. At their leading ends the thread forming ridges are beveled, as at 25.

For the performance of a thread rolling op-- eration a work piece is fed between the overlapped end margins of the, dies. Here a relieved marginal portion 24 of the die 2 prevents its escape, and the die 2 is moved in the direction of the arrow of Fig. 4 or 5 to bring the stepped ridges into action successively.

In Figs. 6 to 13 inclusive the sequential engagements of the ridges with the work piece are shown diagrammatically. In these views the ridges are shown as of V-form in order to simplify the illustration, and where the ridges are shown as traveling in grooves or groove convolutions formed earlier in the operation said rooves are represented as larger than the ri ges to distinguish them from grooves which are being intially formed by ridges. J The opposed ridges 3 and 12 of the two dies are so located that at the beginning of thethread rollingoperation the leading end of ridge 3 will be disposed directly opposite the" space between the leading end of the ridges 12 diametrically across the work piece W, as shown in Figs. 4 and 6. Thereby the -work piece is held by said ridges at three points symmetrically located with reference to a line X perpendicular to the die faces. This symmetrical ridge engagement with the work piece continues throughout the first half turn of the work piece. beginning of the second half turn of the work 55 piece, as shown in Fig. 7, one of the ridges At the 12 enters the groove 3. formed bythe ridge 3, the other ridge 12 and the ridge 13 start to form grooves at opposite sides of groove 3. Simultaneously,.at the opposite side of the work piece the ridge 3 and one of the ridges 4 enter the grooves 12 previously formed by the ridges 12, and the other ridge 4 and the ridge 8 start to out new grooves.

It will be seen that the initial thread forming points are againsymmetrical with respect to line X and that there are now four of them, axially advanced one half pitch space at opposite sides of the work piece. At the beginning of the third half turn of the work piece, as shown in Fig. 8,

one of the ridges 14, ridge 13, and the ridge 12 enter the previously formed grooves 4, V

12 and 8 and the outermost ridges 14'and 20 start to form new grooves. Simultaneously, at the opposite side of the work piece,

the two ribs 4 and the'rib 3 enter the previously formed grooves 3", 13 and 12 and the.

ridges 6' and 9 at the opposite side of the work piece start to form new grooves while the intervening ridges enter previously formed grooves. At the beginning of the fifth half turn of the work piece, as shown in Fig. 10, the

outermost ridges

16 and 21 at one side of the work piece and the outermost ridges 7 and 9 at opposite sides of the work piece begin to form new grooves while the intervening ridges enter previously formed grooves. At the beginning of the sixth half turn of the work piece, as shown in Fig. 11, the outermost ridges 17 and'21 atone side of the work piece and the outermost ridges 7 and 10 at the opposite side thereof start to form new grooves while the intervening ridges at both sides enter previously formed grooves. Thus throughout the major portion of the rolling operation the thread forming action at 'both sides of the work piece constantly occurs atpoints symmetrically located with respect to line X. These points advance equally in opposite directions from said line one half pitch space, or one half the lead of the thread,

tion the ridges 10 and 11 of die 1 and the ridges 22 and 23 of die 2 come into successive engagement with the work, as doalso the uppermost ridges of the dies.-. v The constantly symmetrical thread form'- ing action of the dies causes theworkpiece to be held in a manner to prevent the ocgagement with the'work and for pro My improved dies have been designed for forming threads of the desired accuracy.

What I claim'is 1. A pair of 'cooperative thread rolling dies having thread-forming ribs oppositely inclined in accordance with the desired thread helix angle at opposite sides of the work and having their leading ends varied in spacing from theleading ends of the dies for successive engagement with the work and for progressive initial thread-forming action at diametrically opposite points of the work 5 constantly symmetrical in location with reference to a line through the work perpendicular' to the working faces of the dies.

' 2.-A pair of cooperative thread rolling dies having thread-forming ribs oppositely inclined in accordance with the desired thread helix angle at opposite sides of the work and varied in length for successive enessive initial thread-forming action at diametrically opposite points of the work constantly symmetrical in location with reference to a line through the work perpendicular to the working faces of the dies and for the ad-, vancement of said points outward in opposite directions one half the thread lead at each side of said line andat each side of the work upon each half turn of the work.

3. A pair of' cooperative thread rolling dies having thread-forming ribs oppositely inclined in accordance with the desired thread helix angle at opposite sides of the work, the medial ribs of the dies being longest and the ribs at either side thereof decreasing in length in definite steps for successive engagement with the work and for progressive initial thread-forming action at diametrically opposite points of the work constantly symmetrical in location with reference to a 'line.through the work perpendicular to the working faces of the dies and for the advancement of said points outward in opposite directions one half pitch distance at each side of said line and at each side of the work upon each half turn of the work.

4. A pair of cooperative thread rolling dies having thread-forming ribs oppositely inclined in accordance with the desired thread helix angle at opposite sides of the work, the medial ribs of the dies having their leading ends nearest the leading ends of the dies and the ribs at either side thereof having their leading ends spaced farther from the leading ends of the dies in definite steps for successive engagement with the work and for progressive initial thread-forming action at diametrically opposite points of the work constantly s mmetrical in location with reference to a llne through the work perpendicular to the working faces of the dies and for the advancement of said oints outward in opposite directions one half pitch distance at each side of said line at each side of'the work upon each half turn of the work.

5. A pair of coo V rative thread rolling dies having threadorming ribs oppositely inclined in their working positions in accordance with 'the desired thread helix angle at opposite sides of the work, the medial ribs of the dies being longest, the ribs at one side thereof being successively shorter in outward steps each equal to approximately the work circumference and those at the opposite side of the middle being alternatey'shorter in outward steps each equal to approximatelyone half the work circumference for'successive engagement of the ribs with the work and for progressive initial thread-forming action at diametrically opposite points thereof constantly symmetrical in location with reference to a line through thework perpendicular to the working faces of the dies and for the advancement of said points one opposite sides of the work and varied in length and arranged to form rib fields upon the dies tapering toward the leading ends of the dies, one of the dies having a pair of contiguous middle ribs of maximum length, I the other die having a single middle rib of maximum length located for engagement with the work at a point opposite the space between the said pair of ribs at the opposite side of the work at the beginning of the rolling operation, ribs at one side pf the middle ribs of the dies being successively shorter in outward steps each equal to approximately the work circumference and ribs at the opposite side of the middle being alternate: ly shorter in outward steps-each equal to approximately one half the work circumfer ence, for successive engagement of the ribs with the work and for progressive initial thread forming action at diametrically opposite points thereof constantly symmetrical in location with reference to a line through the work perpendicular to the working faces of the dies. and for advancement of said points one half pitch distance at each side of saidline and at opposite sides of the work, upon each half turn thereof.

7. A pair of cooperative thread rolling dies having thread forming ribs defining a rib field upon each die tapering toward the leading end of the die, the middle ribs of the 5 fields havin their leading ends nearest the leading ends of the dies, the ribs at one side of the middle having their leading ends successively farther from the leading ends of the dies in outward steps and the ribs at the opposite side of the middle having their leading ends farther from the leading ends of the dies in alternate succession by outward steps.

8. A pair of cooperative thread rolling dies having thread forming ribs defining a rib field upon each die tapering toward the lead.-

ing end thereof, the middle ribs of the fields having their leading ends nearest the leading ends of the dies, the ribs at one side of the middle having their leading ends altero nately farther from the leading ends of the dies by outward steps each equal to approximately one half the circumference of the work, the ribs of one die at the opposite side of the middle having their leading ends in v succession farther from the leading end of the die by outward steps each equal to approximately one circumference of the work and the ribs upon said opposite side of the middle. of the other die also having their leading ends farther from the leading end of the die in succession by outward steps, the first step being equal to approximately one half the work circumference and the succeeding steps being equal to approximately one circumference of the work.

9. A pair of cooperative thread rolling dies i 10. A pair of cooperative thread rolling dies having thread forming ribs defining a rib field upon each die tapering toward the leading end of the die, the middle ribs of the fields having their leading ends nearest .the leading ends of the dies and the ribs at the opposite sides of the middle in both fields having their leading ends spaced rearward by successive outward steps from the middle ribs.

In testimony whereof I hereunto aflix my signature.

- ROBERT THOMSON.

having thread forming ribs defining a rib field upon each die tapering toward the leading end thereof, one die having a pair of middle ribs starting side by side nearest the leading end of the die, the other die having a single middle rib starting nearest its leaddie with the pair of middle ribs having the ribs at the opposite side of the middle ones starting in succession farther from the leading end by outward steps each equal to approximately one circumference of the work and the ribs upon said opposite side of the middle of the other die also starting farther from the leading end in succession by outward steps, the first step being equal to approximately one half the work circumference and the succeeding steps being equal to approximately 'one circumference of the work, and the single middle rib being disposed for location of its leading end diametrically opposite the space between theleading ends of the pair of middle ribs upon the other die at the beginning of a rolling operation.