US1416059A - Thread-cutting die - Google Patents

Description

6;]. PIHL, (NOW BY JUDlClAL CHANGE OF NAME C11 PIEL).

THREAD cunme'ms. APPLICAT ION FILED APR. 18,1919. RE NEWED JULY 10, 1920.

1,416,059, 1 Patented Ma '16,1922.

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CARL J'. IPIHL, (NOW BY JUDICIAL CHANGE OF NAMECARL J, PIER) OE BOSTON, MASSACHUSETTS. i

THREAD-CUTTING DIE.

intense.

Specification of Letters Patent. P te ted 31 ,16 1922 Application filed April 18, 1919, Serial No. 291,375. Renewed. July 10, 1920. Serial No. 39 5,38 1.

To all whom it may concern:

Be it known that I, CARL J. PIHL, (now by judicial decree named. CARL J. Irnn) a citizen of the United States, and resident of Boston, countyof Suii'ollr and Commonwealth of Massachusetts, have invented certain new and useful Improvements in h dC n Dies, of which the following is a full, e

The objects of this invention are to produce a die constructed in sections in such a manner that when in use the sectionscan be accurately positioned and maintained in such positionby positively reliable holding means which permits the ready disassembling of the die sections for the purpose of regrindingr A further object is to so form and construct the sections comprising the complete die that there will be provided ample clearance beyond each cutting edge so as to avoid the dragging or rubbing of the internal edge of each section againstthe cylindrical surface of the work formed by the cuttin edge.

For holding purposes I make the die in ear, and exact specification.

sections which are held together as a unit by a clip orencirc-led holder of novel construction which facilitates the positive alignment of the die sections with one another while holding them together as a unit for handling when outside ofthe die stock.

Another feature of the invention consists in the peculiar form and construction due to a method of constructing the die sections so that there will be provided ample clearance back of each cutting edge on the inside surface of the die.

These and other features of the invention will be particularly explained in this specification'and willbe defined in the claims hereto anneged.

In the accompanying drawings I have illustrated the preferred form of the invention together with certain modifications thereof in which I Figure 1 is a main assembled'view showing the assembled die o'peratively held in the die stock. a

Figure 2 is a detail viewfof the sectional die assembled for insertion into the die stock.

Figure 3 is a detail view of a modified formof the holding clip.

F gure 4 s an assembled view of the die sections enclrcled' by an 'a11nular holding 0 1p.

ferred form of holdingclip.

Figures 6, 7, and'8 show modified forms of holding clip both separated and assembled characterized by arectangular formatlon- I Figures 9 and 10 are enlarged views showing the method of cutting forming I the sectional die. l

I will first describe the method of constructing/the die sections which form the 5 providedvwith four pairs of setscrews 7 an'd' 8 which are threaded radially so as to pro ect inward through said holding ring.

The screws are then adjusted so that the straight or radial edges of each quadrant are pos tioned w1th one such edge extend- Figure 5 is a detached view of preing beyond the center while theother edge I is retracted the "samedistance away from the center. In this way all four quadrants? are offset along both radial edges infrelation, to the center of the holding ring, such offset being a symmetrical by reason of the fact that one side edge is retracted from the center while the other side edgeis advanced beyond it. 1

When all foursections have been thus sesurely offset in the holding ring a hole is centrally bored concentric with thebe'nter of theholding ring'andthe interior surface of said centralhole is then tapped to form the proper threads, After the boring and tappin operation four smaller holes corresponding to the number of the sections are bored symmetrically so as to, intersect" each pair of adjacent edges of the die and the periphery of said; central hole as shown in Figure 10. If preferred howeverjfthe boring of the small symmetrically arranged holes 11 may precede the threading or tapping of the central hole. When so boron and threaded the die sections are ready for assemblage and use.

F or such assemblage i prefer to employ a clip such as is shown in Figures 1, 2 and 5 which is a flat spring metal ring '13 having right angle flange 20 extending inwardly from one side edge and having two inwardly projecting hooks at the ends of the ring.

By using this construction the tour sec tions can be readily inserted from the open or unfianged side of the clip and forced down against the retaining flange or lip 20 with strong pressure so as to secure positive alignment in the same plane, the hooks 14 serving to securely grip and hold the sections against circumferential or other di placement without requiring the spring clip to be unduly sprung or expanded beyond its normal die-holding position in the eilort to pass the hooks over the short radial gap between two of the die sections.

In Figure 3 I have shown a ring formed without the right angle flange or retaining lip and in Figure 4: I have shown the sections assembled with a clip having no retaining hooks. However, I prefer to use the hooks since they tend to position the die sections firmly against each other except where the gap is left at the open side of the clip. Moreover, the hooks receive the thrust of the expanding or'anchoring screw l6carricd by the stock so that there is less likelihood of producing any offset laterally from the plane of the die than if the screw has direct engagement with the die sections themselves.

The ring 15 of the die stock is made so as to easily admit the die sections in assembled position and is provided with the main setting screw 16 and any suitable number of peripheral holding screws 17 for firmly securing the die within the stock.

The boring of the small holes 11 leaves I each die with a cutting edge 19, the point of said cutting edge projecting very much fan ther inward toward the center of the die than the interior threaded portions of the die between the holes 11; Owing to the fact that the threaded surfaces of the dies are formed on circles that are ofi'set laterally in two directions from the center of the as sembled dieiithere is a sharp angle of divergen'ce produced between the curve of the ,threads and the circle passing through the extreme cutting edges so as to afford amply suficient clearance of the threaded surfaces of the die backer each cutting edge.

It will be observed that the adjacent or opposed edges oi; the two die sections 1 53 located adjacent to th racial gap are bevelled to bear against the end of the set screw i6 and that the hooks let of theclip are formed to ride fiat against said bevelled surfaces.

What I claim is:

l. A die comprising a plurality of threadbearing sections separable one from another and a spring clip pe ipherally binding them together said clip having an inturned hook at each end adapted to engage the opposed surfaces of two adjacent sections, substantially as described. I

2. A die comprising a plurality of diecutting sections separable one from another the adjacent edges of two sections being bevelled, and a spring clip peripherally binding the sections together, the ends of the clip having inturned hooksengaging said bevelled ends, substantially as described 3. A thread-cutting die comprising a plnrality of sections provided with internally threaded cutting edges, means for positioniug'and holding said SQClDlOIlF' in proper alignment comprising an annular clip hav ing; inwardly turned hooks and having an inwardly turned lip or flange adjacent to one side edge of the clip. substantially as described.

4. A thread-cutting die embracing in its construction a plurality of sections formed with interior threaded cutting-edges and a holdinc: clip adapted to surround and hold said dies in. position said holding clip being provided on one side edge with an inturncil flange or lip wherebythe die. sections may be inserted from the opposite side) without distorting or springing the clip beyond its normal. holding position. substantiallv as described. i

5. A thread-cuttin die comprising a pluralityoi" sections each having an inwardly proiectinc: thread-cutting edge, the internal. surface back of each cutting edge being: formed on a center that is laterallv ofiset to the diametrical line interse ting the middle point of the peripheral arc of. the sedttioni substan ially as d escrihed.

6, A thread-cutting die embrac g in its construction pluralitv of sector shaped sections whose inner threaded surfaces entend on circles described about differen centers that are laterally oil'set with relation to the middle radius of each die section of the assembled die, substantiallv, as'described.

7. A threadmuttinc: die embracing in its construction a plurality of separable sections each of which is provided with inwardly projecting: cuttine ed es in advance of internal surfaces formed on a circle described about a center that is asymmetrically 'ofiset with relation to the two radial ed ores of each die section in order to provide a sufficient angle of clearance behind each cutting edge, substantially as described.

8. A thread-cutting die embracing in its construction a plurality of sector shaped die sections a circumferential holding clip comprising a contractible split ring provided with an inturned flange presenting a side thrust surface at right angles to the axis of the die thereby affording a positive stop in contact with a side surface of each die section, substantially as described.

9. A thread cutting die comprising a plurality of sectorseach of which is formed with outside and inside circular surfaces, the inside circular face being described on a center that is asymmetrical to the outside cir cular surface whereby the sectors when assembled with their outer surfaces concentric will present interior cutting edges provided with an ample clearance behind each cutting edge.

In testimony that I claim the foregoing inyention, I have hereunto set my hand this 17th day of April, 1919.

CARL J PIHL.

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