US2352141A - Die roll and method of making the same - Google Patents

Description

June 20, 1944. l:` ULRlCH DIE ROLL AND METOD OF MAKING THE SAME Filed June 14, 1940 mimi 0R FREDERICK ULRICH BY y INVENT ATTORNEYS Patented June 20,` 1944 DIE ROLLAND METHOD' 0F m Sm MAKING Frederick Ulrich, Bayonne, N. I., assigner to Conv Corporation, Bayonne, N. I., a corporation of New Jersey Appueeuen .me 14. ist, serai Ne. 340,436

g2 claims. (c1.- '1s-m) mar Products This invention relates to die rolls, particularly for the rolling of slide fastener wire.

vIn recent years a process for making slide fasteners has been developed which includes the rolling of wire under high pressure between very small-diameter coining rolls to compress and deform the wire into a connected series of embyro slide fastener elements. This wire is subsequently severed into individual elements which areattached to a tape as they are severed from the wire. The process is described in Wintritz Patent 2,201,068 issued May 14, 1940, and entitled Manufacture of slide fasteners.

Because of the small size of the rolls (say, one inch in diameter), and the large pressure and torque required. the rolls are preferably overhung and carried by massive shafts and bearings, the shafts .being driven through heavy gearing and an appropriate countershaft. The rolls are each provided with'an integrally formed sidewardly projecting shank or arbor,v preferably tapered,l which is received in the shaft.

'I'he die impressions are formed in the roll by first making a master punch which is negative to a single impression, and mounting the punch in the head of a press the table of which is providedwith a suitable fixture carrying the .roll and arranged to rotate the same intermittently an amount equal to the spacing between die impressions. After, small, initial impressions have been formed entirely around the roll,

-the punch is fed downwardly a small amount, and this operation is repeated until the impressions are of fulldepth. The primary object of my invention is to generally improve die rolls of the above described character'.` Another object of the invention is to vfacilitate the' manufacture of thel rolls, and a still further object is to greatly lengthen the useful operating life of the same.

To the accomplishment of the foregoing general objects, and other more specific objects which will hereinafter appear, my invention consists in the die roll elements and method steps and their relation one tothe otlfer, as hereinafter are more particularly described in .the

specification and sought to be defined in the claims. The specification is accompaniedby a drawing, in which: V

' Fig. 1 is a side elevation of the blank which `may be used to form adie roll:

Fig.2 is an end view of the same;

Fig. 4 is an end view of the same;

Fig. 5 is'an enlarged partially* sectioned end elevation of a fragment of the die roll after hobbing the coining impressions in the same;-

Flls. 6 roll;

Fig. 7v is an end elevation of the same; 1 Fig. 8 is a fragmentary'view of a male die roll after hobbing and before finishing; Fig. 9'is asimilar view after. finishing; and Fig. 10 is explanatory of the 'method of hobbing the die'roll. t

Referring to the drawing. and more particularly Figs. 6 andI 7, the die roll there shown comprises a working portion i2 provided with a sidewardly extending shank Il.' the latter being used because the die roll I2 and its 'mating die roll are relatively ove'rhung. the shanks being received within massive shafts carried by massive bearings and driven through large gearing and a countershaft, alias is set forthy in greater detail in the aforesaid Wintritz Patent No. 2,201,068. The shank il may be a tapered shank as shown, the illustrated example having a taper of'fifteen degrees. If the tapered lshank is to be drawn into the shaft.I by means of a threaded draw-bolt, the shank i4 is preferably drilled and threaded, as is indicated at II. The working portion I2 has heretofore been left solid.

1 have f eund that is extremen beneficial te hollowthe working portion I2. as is indicated bythe counterbore i8. I have found that the useful operating life of the rolls is substantially increased. in fact may be doubled, by hollowing the roll as 'here indicated, instead of leavlnl the same solid. This' maybe considered an empirical discovery, and any explanation herei inafter given, is.. entered merely as er possible ne1pg1n explaining' the beneneiei rermts ebtained. and is not to be construed in anyl way action of the press by a special .cradle or sup- Fig. 3 is a partially sectioned side elevation the blank:

as a limitation of the invention.

At the outset it should be understood that the coining` impressions 20 on the roll are 'formed 'by hobbing or coining the same into the roll.

Thus, referring te Fig. 10;.the ren .blank 22 is mounted in a special fixture carried on the.

table of a standard press, this fixture including centers 24 and 2C which receive the roll 22, butA the latter is additionally supported against the port bleek u. A dos :n is secured te blank z2 land a pilot wheel 32, the latter being mounted on a shaft 8l carrying a suitable ratchet wheel Il. The latter is operated on by a pawl (not is a. side elevation vof a iinisheddie The slide Il of the press carries" a master punch 40 the end of which is shaped to produce one of the desired shapes or recesses in the die roll. Slide 38 is moved by a pitman 42 includ- 'ing a pitman screw 44 having a capstan head 48 which may be t'u'rned by'a capstan bar 48.

'I'he slide Il carries a pilot pin 5I) which operates in the pilot holes extending about the periphery of pilot wheel 32.

With this arrangement the pitman screw'44 `may be turned until master punch 40 lust begins to indent the surface of the roll blank 22. Continued operation of the press causes fractional' rotation of the roll Wtil 'the initial slight impressions have been exried entirely around the roll. If desired, a counter 52 operating through link 54 from shaft 34 may be employed to stop the press after the impressions have been carried around the roll. The'capstan bar 4I may Referring now tol Fig. 5, the hollowed surface impression there shown corresponds to a conventional slide fastenerelement, the projection on the head of the fastener element being formed ,at the relatively deep recess 60, and the spread jaws of the fastener-element being-formed at the moderately deep recess 82. The shallow portion 64 cooperates with a raised portion on the mating roll to form a thin web of metal between the spread laws of the fastener element.- The deep recess 86 forms `the head of the next fastener element.

The pressure of the bobbing punch n(40 in Fig.- tends to produce a sideward and upward displacement of ,metal on the roll. In fact, it would be difficult, as a practical matter, to obtain a perfectly uniform' series of uniformly spaced die impressions by forming any one recess to full depth' before beginning the next adjacent recess. It is largely for this reason that the master, punch is advanced only a very small` amount, say a few thousandths of an, inch at a time, and the entire ring of impressions is formed aroundthe roll at each new depth before again advancing the punch.

Another, and, I believe, much more important difiiculty is that the grain size of the metal is reduced .to a much smaller value beneath the deeper parts of the impressions than beneath the shallow parts of the impressions, and a'difference in grain size may remain despite all eiforts at normalizing the metal after finishing the hobbing operation.

In accordance with my invention, the roll is hollowed or provided with a relief hole instead of being left solid. This facilitates inward displacement of metal, that is, it provides a better outlet for movement of the metal than when using a solid roll. Thus, in Fig. 5, the initial internal diameter of the roll may be that indicated at10. The internal diameter at the impressions'may be reduced to that shownat 12 saam I shown) actuated by the successive reciprocations of the press.

operation, for the latter evidences only a slight upward displacement of metal, while the former evidences a greater displacement of metal. Moreover, careful measurement will show thc change -in internal diameter of thehollow roll here indicated by the lines 10 and 12.' I believe there is also less change in the grain size of the metal'and less distortion` and strain within the metal. Ihus the product is a better product after normalization,y and in actual practice, I

have found an astonishing increase in the useful operating life of the die rolls, the life being increased about one hundred per cent.

Referring now to Figs. 1 and 2, the die roll blank 14 may be made of uniform diameter, the diameter slightly exceeding the final roll diameter. The roll is made longer than the die roll, it comprising a shank portion 16, an intermediate portion Il which corresponds to the working portion of the roll, and an extra end portion 80 which is adapted to be cut away later, this end. portion being provided so that the roll may be symmetrically supported on each side of the working portion 'Il during the hobbing operation, and also to prevent 'excessive displacement of metal in that direction compared i to the displacement in opposite direction. The

blank 14 is finished on the inside, it being provided with the thread It previously referred to, and the I4hollow I8. It is also provided with tapersfor centers, there being one such taper at Bland another at 84. These tapers may have the standard sixty-degree angle, and the center used with taper 84 is preferably left small ,enough to be received within the-internal diameter 86. A fiat may be provided at 88 for cooperation with the set screw of dog 30 previously referred to. This fiat disappears when the shank is later finished to the desired tapered configuration. Figs. 3 and 4 illustrate an intermediate step which may be followed if desired. The outside surface is ground at $0 to a smooth finish and exact dimension. If desired, the part!! may be reduced slightly in diameter so that the grinding operation may be localized tothe portion 90 instead of being carried over the entire blank. The part 90 is still of excess diameter, it having substantially the same diameter as'the roll in Fig. 1. It is ground merely to insure accurate seating of the roll on support 28 (Fig. 10), and accurate h obbing.. t

The blank isl then mounted between'the centers 24 and 28. as wasp described in connection with Fig. 10, the ground portion resting on the support cradle 28. y

After completion .of the hobblng operation, the blank is machined to finished dimension, as

shown in Figs.` 6 and 7. `At this time the working portion is turned to desired diameter, the shank portion is turned to desired taper, and

l the excess lend portion l0 (Figs. 1 and 3) is cut after completion of the hobbing operation. The i away. l l

The roll is then normalized, preferably. by heating the same to a suitable temperature for many hours, and then gradually lowering the temperature to normal. The normalizing process may extend over a period of, say, thirty-six hours, and is intended to improve the grain structure of the roll and to eliminate internal stresses caused by working of the metal.

The roll is then hardened. The material here employed is a tool steel, preferably a high chromium content tool steel, such as crucible CCA TS. With this material the roll may be air-hardened, that is, heated to a suitable temperature and held at the exact desired temperature, and finally cooled vwithout necessitating quenching. The roll is then tempered, this being preferably done in an oil bath. The roll is 'then checked for hardness and may, for example, be given a hardness of Rockwell 61-63. The roll is then ground and polished both for the from mel spirit of the mensen sought to be outside diameter at the working portion, and for 1 the taper. The hollowing of the roll is probably of benet during all of the heat treatments, as it better exposes the metal for more uniform treatment.

The invention is particularly applicable t'o rolls intended to accomplish relatively deep coining of irregular shapes in a wire in the course of only a single passage ofthe wire' through the rolls. For this purpose. the rolls are preferably small in diameter. They may, for example, be one inch in pitch `diameter. For such a roll I recommend an internal diameter of flve-eighths of an inch. The specinc roll illustrated. has a pitch. diameter of one inch,but an outside diam- 1.129 inches. The initial diameter of the blank is 1.152 inches. This is because the roll is made as a "female" roll which cooperates with a from a side of said working portion. the'cyiindriveter of about 1% of an-inch, or more exactly,

male roll having a mailer diametenlbut with projections thereon.

The hollow or hole dimension is somewhat critical because if the internal diameter is too small, then the benentv obtained from hollowing the roll 'may be diminished or even lost, and on the other hand, if the wail thickness is made too small, the roll may not stand up, particularly under the hobbing operation.' In other wcrds;'

the diameter may be excessively reduced. This .is particularly true when making the male roll for cooperation with the female roll so far described.

Thus, referring to Fig. 9, the male roll has a raised impression I4 projecting from the roll surface Il (the latter being less than one inch in.

diameter). To do this, the blank is initially made of larger diameter, as is indicated at 98 in Fig. 8, and the master punch lndents the materiai at |09 around the desired projection 86.

of formationof the desired projection Il.

Gf course, the optimum wall thickness may vary with a number of factors, such as the nature of the material used, and the size', conflguration and depth of the impressions being coined in the roll. here disclosed, I have found that the internal diameter of the roll should not be increased above the recommended diameter of flve-eighths of an inch. by even so much as on an inch, for the With the specific kind of roll resulting loss of wall thickness will prove notice- -tages thereof, will be apparent from the foregoing detailed description. It will alsobe apparent that while I have shown and described my invention in a preferred form, manychanses and cal portion of said roll being hollowed or counvterhore'd toa diameter approximately one-half the roll pitch diameter to lessen the upward displacement of the metal during the indenting or coining operation.

2. A die roll for vcoining wire to a desired shape including projections and recesses along the wire, said roll being relatively free of internal stress and comprising a cylindrical portion having4 a series of die impressions hobbed uniformly '-therearoundby indenting or coiningthe impressions by pressure applied radiailyinwardly, a tapered shank formed integrally with and projecting from one side of said cylindrical portion, the cylindricalportion of said roll being hollowed or counterbored lto facilitate desired displacement o f metal during' the hobbing operation, but leav. ing adequate wall thickness for the bobbing and rolling operation, the hollow interior having a slight ridge'or reductionin diameter within the hobbed impressions caused by hobbing-of the impressions.

3. A die roll for coining slide fastener wire, said roll being relatively free of internal stress and lcomprising a cylindrical portion of the order of one inch in diameter having a series of die impressions hobbed uniformly therearound by indenting or coining the 'impressions `by pressure applied radially inwardly, each impression having parts of different depth, a tapered shank formed integrally with and projecting from one side of said cylindrical portion, the cylindrical portion of said roll being hollowed or counterbored, the hole in said roll having a diameter somewhat more than one-half the .pitch diameter of the roll.

4. A die roll for coining slide fastener wire, said roll being relatively free of internal stress and being` made of a high chrome tool steel, said roll comprising a cylindrical portion approximately one inchv inpitch diameter having a series of die impressions hobbed uniformly therearound by indenting or coining the impressions by pressure applied radially inwardly, each im- -pression having parts of different depth, a

tapered shank 'formed integrally with and projecting from one side of said cylindrical portion,

lin diameter within the hobbed impressions. .caused by hobbing of the impressions.

5. A steel blank,v for an overhung die roll hav- 'lng relatively deep impressions indented or coined by blows applied radially inward on its outer surface, and having a shank projecting from one side thereof, said blank being cylindrical and having a main end portion adapted to subsequsntly form the desired shank, and a portion adapted to subsequently form the cylindrical modifications may made without departing fd working portion of the roll, the .working portion being hollowedto so 'great an extent as to -lessen .sideward and upward displacement of metal during the hobbing-operation and to maintain a' more nearly uniform grain` structure when hobbing and normalizing.

6. A steel blank, for an overhung die roll having relatively deep impressions indented or coined by blows applied radially inward on its outer surface, and having a tapered shank projecting from one side thereof, said blank being` cylindrical and having a main end portion adaptin the opposite direction, thereafter finish-maed to subsequently form the desired tapered shank, an intermediate portion adapted to subsequently form the end cylindrical working portion of the roll, and an end portion beyond the working portion, whereby said roll may be symchining the roll to cut o ff the excess length at one side ofthe die impressions, and then normalizing and hardening the roll.

11. In the manufacture ofhobbed die rolls by t indenting or coining the same by blows applied metrically supported on each side of the working portion while the latter is being hobbed to form the desired die impressions therein, the working f portion being hollowedto so great an extent as to lessen sideward and upward displacement of metal during the hobbing operationand to maintain a more nearly uniform grain structure when hobbing and normalizing and the end portion beyond the working portion functioning to prevent excessive displacement of metal in that direction compared to the displacement in opposite direction.

'7. In the manufacture of hobbed die rolls by indenting or coining the same by blows applied radially'inwardly on a cylindrical surface, the method which includes the step of counterboring or hollowing the die roll blank prior to hobbing the same toso great an extent as to minimize internal strainsY otherwise caused bythe coining operation, but leaving adequate wall thickness to withstand the hobbing and subsequent die rolling operations, and keeping the same hollow during the hobbing operation.

8. In the' .manufacture of small diameter hobbed die rolls having a generally cylindrical working portion and a shank formed integrallytherewith and.- projecting sidewardly therefrom, the method which includes the step of counterboring or hollowing the die roll blank prior to hobbing the same to so great an extent as to order of one inch, and includingV` a tapered shank' formed integrally therewith andprojecting sidewardly therefrom,'the method which includes the step of counterboring or hollowing the working portion of the die roll blank to a diameter of the order of ve-eighths of the roll diameter, prior to hobbing the same, and then coining the working portion by blows applied radially inward.

10. In the manufacture of a hobbed die roll consisting of a small cylindrical portion anda shank formed integrally therewith and projecting sidewardly therefrom, the method which includes forming a cylindrical blank longer than the die roll, boring or counterboring said blank to hollow the same to so great an extent as to minimize internal strains otherwise caused by blank at both ends in a hobbing press and hob- I 'bing the desired die impressions therearoundV by' radially inwardly on a cylindrical surface, the method which includesthe step of counterboring or hollowing the die roll blank prior to hobbing the same, to so great an extent as to minimize internal strains otherwise caused by the hobbing operation, but leaving adequate wall thickness to withstand the hobbing and subsequent die rolling operationsykeeping the same hollow during the hobbing operation, coining the cylindrical surface by applying a blow radially inward, i-

-tating the blank an amount equal to the spacing between die impressions, applying another blow radially inward, and so on until the blank has been turned through one or more revolutions.

12. In the manufacture of small diameter hobbed die rolls having a generally cylindrical working portion and a shank formed integrally therewith and projecting sidewardly therefrom, the .method which includes the step of counterboring or hollowing the die rollblank prior to hobbing the same, to so great an extent as to minimize internal strains otherwise caused by thehobbing operations, but leaving 'adequate wall thickness to withstand the hobbing and subsequent die rolling operations, coining the cylindrical surface by applying a blow radially inward, rotating the blank an amount equal to the spacing between die impressions, applying another blow radially inward, and so on until the blank has been turned through one or more revolutions.

13. In the manufacture of hobbedv die rolls the order of ave-eightns of the roll diameter,- prior to hobbing the same, coining the cylindrical surface by applying a blow radially inward, rotating the blank amount equal to the spacing between die impressions, applying another blow radially inward, and s o on until the blank has been turned through one or more revolutions.

14. In the manufacture of a die roll consisting of a small cylindrical portion and a shank formed integrally therewith and projecting sidewardly therefrom, the method which includes forming a cylindrical blank longer than the die roll, boring or counterboring said blank to hollow the same,- supporting said 4blank at both ends in a hobbing press and hobbing the desired die impressions therearound at a point spaced substantially further from the end oi the blank than they are intended to bespaced from the end of the roll, the hobbing operation being performedby coining the cylindrical surface by applying a blow radially inward, then rotating the blank an amount equal to the spacing between die impressions. applying another blow radially inward, and so on until the blank has been turned through one or more revolutions, thereafter iinish-machining the roll to cut off the excess length at one side of the die impressions, and then normalizing and hardening the roll.

15. In the manufacture of hobbed die rolls by indenting or coining the same by blows applied radially inwardly on a cylindrical surface, the method which includes the step of counterboring or hollowing the die roll blank prior to hobbing the same, to so great an extent as to minimize internal strains otherwise caused by the hobbing operation, but leaving adequate wall thickness to withstand the .hobbing and subsequent die rolling operations, keeping the same hollow during the hobbing operation, coining the cylindrical surface by applying a blow radially inward,`ro tating the blank an amount equal to the spacing between die impressions, applying another blow radially inward, and so on until the blank' has been turned through one or more revolutions,

l thereupon applying a blow more deeply radially inward, rotating the blank, and so on until the blank has been turned through one or more revolutions, and repeating this process until the die impressions have been struck inward to desired full depth.

16. In the manufacture of small diameter hobbed die rolls having a generally cylindrical working portion and ashank formed integrally therewith and projecting sidewardly therefrom, the method which includes the step of counterforming a cylindrical blank longer than the die roll, boring or counterboring said blank to hollow the same, supporting said blank at both ends in a hobbing press and hobbing the desired die im pressionstherearound at a point spaced substantially furtherl from the end of the blank than they are intended to be spaced from the end of the roll, the hobbing operation being performed by coining .the cylindrical surface by applying a blow radially inward, then rotating the blank an amount equal .to the spacing between die im boring' or hollowing the die roll blank prior to so on until the blank has been turned through one or more revolutions, and repeating this process until the'die impressions have been struck inward to desired full depth.

1'7. Inv the manufacture of hobbed die rolls having a small diameter working -portion of the order of one inch, and including a tapered shank formed integrally therewith and projecting siderwardly therefrom, the method which includes the step of counterboring or hollowing the working portion of the die roll blank -to a diameter of the order of ve-eighths of the roll diameter, prior pressions, applying another blow radially inward. and -so on until the blank has been turned through one or more revolutions; thereupon ap plying a blow more deeply radially inward, then rotating the blank, and so on until the blank has been'turned through one or more` revolutionsand repeating this process until the die impressions have been struck inward to desired full depth, thereafter finish-machining the roll to cuty oli the excess length at one-side of the die impressions, and then normalizing and hardening the roll.

19. A relatively stress-free hollow die roll made in accordance with the method of claim '1.

20. A .relatively stress-free die roll having a hollowv working portion, the exterior of said die roll having impressions indented therein by coining pressure exerted from `the outside towards the inside, the hollow of said die roll being'of a size sufficiently large as compared to the .roll dito hobbing the same, coining the cylindrical surface by applying a blow radially inward, rotating the blank an amount equal to the spacingbetween die impressions, applying another blow radially inward, and so on until the blank has been turned through one or more revolutions,

y thereupon applying a blow more deeply radiallyv inward, rotating the blank, and so on until the 'blank has been turned through one or more revolutions, and repeating this process until the die impressions -have been struck inward to desired full depth.

18. In the manufacture of a die roll consisting -of a small cylindrical portion and a shank formed integrally therewith and'projecting sideameter to facilitate the displacement or flow of the metal inwardly during indentation of the exterior and to help` provide the stress-free characteristic but leaving adequate wall thickness for the indenting and rolling-operations, and the interior of the die roll having a slight ridge or reduction in diameter at the impressions, caused ,by the indenting of the exterior.

21.1A small die roll relatively free of internal stress, said die roll having a hollow working p0rtion the outside diameter of which is of the order of one inch, the exterior of said die roll havingv impressions indented therein by coining pressure 'K exerted fro'm the outside towards the inside', the

hollow oi said die roll being of a size to facilitate the displacement or flow of the metal inwardly during indentation of the exterior and to help provide the stress-free characteristic but leavingv adequate wall thickness for the indenting and rolling operations.

22.1 A relatively stress-free die roll for coining wire to a desired shape including projections and recesses along the wire, said roll comprising a working portion having aseries of die impressions hobbed uniformly therearound by indenting or coining the impressions by pressure applied radially inwardly, and a shank formed integrally with and projecting from a side of said working portion, the working portion of said roll being hollowed, the hollow of said working portion being of a size su'iilciently large as compared to the roll diameter to facilitate the displacement or now of the metal inwardly during the indenting or coining of the working portion but leaving aciequate wall thickness'for the indenting and rolling operations, the hollow interior having a slight ridge or reduction in diameter within the hobbed impressions, caused by hobbing the impressions.

Y FREDERICK ULRICH.

wardlytherefrom, the method which includesv

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