US2542023A

US2542023A - Method of making nuts

Info

Publication number: US2542023A
Application number: US547849A
Authority: US
Inventors: John H Friedman
Original assignee: National Machinery Co
Current assignee: National Machinery Co
Priority date: 1944-08-03
Filing date: 1944-08-03
Publication date: 1951-02-20
Anticipated expiration: 1968-02-20
Also published as: GB601977A

Description

- Feb. 20, 1951 J, H. FRLEDMAN I 2,542,023

METHOD OF MAKING NUTS Filed Aug. 3, 1944 2 Sheets-Sheet 1 mmvro J N H. FR/ID v BY 7 I 274% T707? NE Y5 Feb. 20, 1951 J. H. FRIEDMAN 2,542,023

METHOD OF MAKING NUTS Filed Aug. 3, 1944 2 Sheets-Sheet 2 10 I I'Za. ig-q k 7% v r IN V EN TOR.

\T HN HF/PLEDMAN BY I M TM A TTOIPNEYS STATES PATENT OFFICE METHOD OF MAKING NUTS John H. Friedman, Timn, Ohio, assignor to The National Machinery Company, Tifiin, Ohio, at

Application August 3, 1944. Serial No. 547,849

nuts and similar articles.

In prior efforts to produce nuts and similar polygonal articles by cold forging the articles from wire or rod stock great difficulty has been encountered in attempting to make the metal flow into the desired polygonal shape so as to reduce sharp, well filled corners. If excessive pressures or excessive metal flow are resorted to. the dies and tools are rapidly destroyed and the metal in the articles is excessively work-hardened, tending to cause such excessive hardness and brittleness that the articles cannot be machined, as required, for example, in the tapping of nut blanks.

I have discovered that this and other dimcultles and problems in the making of such articles can be overcome by shaping a blank with respect to a die to cause the blank itself to act as a force multiplier, so that the desired metal flow is obtained without applying excessive pressures to the blank.

Another feature of the present invention is the of the metal in a blank with respect to a die so that the necessary pressure per unit area is applied to small areas of the blank requiring the greatest flow with a substantially smaller unit pressure applied to the face of the blank.

In one embodiment of the present invention such force multiplication and increased unit pressures are obtained in somewhat dlflerent ways in each of two separate steps. In each step a blank is upset into a die which has at least a portion of its end face arranged at a greater angle with the adjacent side wall of the die than the corresponding angle between the end face and side wall of the blank. Thus when the blank is upset into the die the blank acts as a force multiplier and applies a greater unit pressure at the corners between the end face and the side wall of the die than the average unit pressure applied to the front face of the blank.

In the preferred embodiment, this action is obtained in one step by upsetting a blank which has side walls substantially perpendicular to its end face into a die with a generally concave bottom, the side walls of which form an obtuse angle with the adjacent portions of the bottom wall of the die. The blank is upset by means of a punch having a generally convex face, producing a dished, or concave-convex blank. In the upsetting action the side walls tend to retain their original angular relationship with the 2 radially outward with great force in the region of the corner between the side walls and the bottom face of the die by a leverage action within the blank itself. All corners adjacent the convex face of the blank are thereby filled completely and sharply.

In the next step in the preferred embodiment, the blank produced by the foregoing operation has its concave face engaged with the bottom of a die recess which has side walls substantially perpendicular thereto. The blank is again upset, and the corners adjacent the concave face are forced strongly outward by a toggle or leverage action. By the combination of these two actions the comers of a polygonal blank are filled completely and sharply with the application to the blank of only relatively low pressures.

Another feature of the present invention is the punching of an axial hole through the blank without distorting the exterior surface or caus me the blank to freeze in a die. This is accom= plished, in the preferred embodiment, by confining the side walls of the blank exteriorly through a portion only of their height adjacent one face of the blank, and forcing a punch into the blank from the other face. The metal of the blank is thereby permitted to spring outwardly during the punching, while permanent deforma tion is prevented by the confining oi the one face and adjacent portions of the side walls. The limited area of engagement between the blank and the die permits the blank to free itself readily when the punch is retracted.

Other objects and advantages of the invention will appear from the following detailed description of a preferred embodiment of the method and apparatus for carrying out the same.

In the accompanying drawings:

Fig. 1 is a sectional view with parts in eleva tion taken through the stock feed station of a machine arranged to carry out the present invention;

Fig. 1-11 is an elevation of a cut-on blank;

Fig. 2 is a sectional view, with parts in elevation, through the next station of the machine;

Fig. 2-a is an elevation of the blank-produced by the die shown in Fig. 2;

Fig. 3 is a sectional view, similar to Figs. 1 and 2, through the dies constituting the next station of the machine;

Fig. 3-a illustrates in cross section and in elevation the blank produced by the dies shown in Fig. 3;

laces of the blank, so that the metal is pressed as Fig. 4 is a sectional view through the next 3 station of the machine, showing the step of dishing the blank;

Fig. 4a illustrates in cross section and in elevation the dished blank produced by the tools shown in Fig. 4;

Fig. 5 is a section through the next station of the machine, showing the step of again flattening the dished blank; i

Fig. 5-41 illustrates in section and in elevation the blank produced by the tools shown in Fig. 5;

Fig. 6 is a section through the punching station of the machine, showing the parts after completion of a punching operation;

Fig. 6a illustrates in cross section and in elevation the punched blank; and

Fig. 7 shows the stripping of the blank from the punch on the retracting stroke of the punching tools.

The dies and tools shown may be mounted in a multiple station transfer header with all of the dies mounted in the bed frame and the cooperating tools carried by a reciprocating header slide, and with a transfer mechanism to carry the blanks from each station to the next and to turn the blank over between each two successive operations. Such a machine is disclosed and claimed in the patent to Frayer No. 2,100,028. The invention, however, is not limited to such a machine, as the method of this invention may be carried out in a plurality of separate machines, by hand, or in one or more multiple station headers of other types, such as the machine disclosed and claimed in the patent to Clouse No. 2,026,823. Similarly, the novel dies and tools of this invention may be mounted in any desired machine or machines, or may be manipulated by hand. For maximum economy of operation, however, it is preferred to utilize a machine which performs all of the operations without intermediate handling, and for simplicity in the mounting of the dies and tools the machine of the aforesaid Frayer Patent No. 2,100,028 is preferred.

Any suitable means may be employed to supply blanks to theprocess. The cut-off mechanism illustrated in Figs. 1 and 2 is of the typ disclosed and claimed in my U. S. Patent No. 2,396,995, granted March 19, 1946, on co-pending application Serial No. 547,886, filed August 3, 1944, a continuation in part of my application Serial No. 423,900, filed December 22, 1941, which has since become abandoned. The bed frame I of the machine is provided with an opening II through which wire or. rod stock S is fed by any suitable feeding means (not shown). A shear arm I3 carrying a bushing or sleeve I4 arranged to surround the stock S is mounted for reciprocation along the face I5 of the bed frame I8. A plunger I6 having a head I! is slidably mounted in and carried by the bushing I4.

When the bushing I4 is in alignment with the hole II the stock S is fed forwardly until the head ll of the plunger I6 engages a stock gauge I8 which is adjusted to permit the desired length of stock to be entered into the bushing I4. Thereupon the shear arm I3 is moved across the face I5 of the bed frame I 0 in the direction of the arrow shown in Fig. 1, so that the edges of the opening I I in the bed frame I0 and the adjacent edges of the bushing I4 cooperate to shear a blank I9 from the stock S.

The shear arm I3 continues to move until the bushing I4 is brought into alignment with the opening in a die 20 mounted in the bed frame I8 as illustrated in Fig. 2. During this move- 4 ment of the shear arm I3 the head I! of the plunger I6 slides across the stock gauge I8, the plunger I6 remaining in position in the bushing I4.

When the bushing I4 is aligned with the opening in the die 28 the motion of the shear arm I3 ceases and a punch 2| mounted in the reciprocating header slide 22 advances against the head ll of the plunger I6. The motion of the punch 2| continues until the plunger I6 forces the blank I9 out of the bushing I4 and upsets the same into the opening in the die 28. The position of the parts at the end of the forward travel of the punch 2| is illustrated in Fig. 2.

In the present process the die 20 is preferably provided with a conical bottom wall 23 surrounding a knock-out pin 24, so that the blank 25, formed in the die 20 has a conical or chamfered surface 26, as shown in Fig, 2a. The upsetting of the blank I8 into the die 20 to form the blank 25 serves to size the blank by pressing it into close contact with the wall of the opening in the die 20, to remove any irregularities of.

the end faces produced by the shearing action, and eliminate any non-uniformities in cross sectional shape which may have existed in the stock S. A spring 21 preferably surrounds the plunger I6 and engages the head I! and the adjacent end of the bushing I4 when the punch 2| has reached the limit of its forward movement as shown in Fig. 2. As the punch 2| is retracted the spring 21 withdraws the end of the plunger I6 from the opening in the die 28 and the shear arm I3 thereupon returns to its position in alignment with the stock feed opening II, as illustrated in Fig. 1. Thereupon the knock-out pin 24 ejects the blank 25 from the die 28, where it is seized by the transfer mechanism and delivered to the next die.

In the illustrated embodiment the next station of the machine embodies a die 28 mounted in the bed frame III and having an opening of hexagonal or other polygonal cross section. The bottom of the die opening is formed by a hexagonal knock-out pin 29 slidably fitting within the die opening. The blank 25 is turned over while being transferred from the die 20 to the die 28, as disclosed in the aforesaid patent to Frayer No. 2,100,028.

A punch 30 mounted in the reciprocating header slide 22 is arranged to engage the blank 25 after the same has been turned over and positioned in front of the di 28 by the transfer mechanism. After engaging the blank 25 the punch 30 forces the same into the die 28 and upsets the blank against the end of the knock-out pin 29 so as to partially form the blank to the polygonal cross section of the opening in the die 28. The punch 38 is arranged to apply only a relatively light upsetting pressure to the blank, so as to shorten the sam and flatten the metal into contact with the flat sides of the hexagon defined by the die 28, without attempting to flow the metal to fill up the corners of the hexagon.

This operation produces the blank 3|, shown in Fig. 3a, having partially formed flat-areas 32 corresponding to the flats of the hexagon defined by the opening in the die 28. As the punch 30 recedes, the knock-out pin 29 ejects the blank 3| from the die 28 into the transfer mechanism to be carried to the next station of the machine.

The blank is again turned over and transferred to a position in front of a die 33 carried in the bed frame I0, illustrated in Fig. 4. "The die 33 has an opening with a hexagonal cross sectional shape corresponding to the shape of the opening 1 in the die 28. The bottom of the opening in the die 33 is formed by a wall 34 in the die having a generally conical shape and disposed at an obtuse angle to the side walls 35 of the opening. A knock-out pin 36 forms the center of the bottom wall 34 and is provided at its end with a nose 3'! arranged to indent the center of the blank.

A punch 38 carried by the reciprocating header slide 22 is arranged to cooperate with the die 33. The face of the punch 38 is provided with a nose 3!! surrounded by a substantially conical surface 40 which is arranged substantially parallel to the conical bottom wall 34 in the die 33.

When the blank 3| is positioned in front of the die 33 it is engaged by the punch 38 and forced into the opening in the die 33. The metal of the blank is upset into the die 33 and by reason of the substantially parallel conical faces 34 and 46 on the die and the punch the blank as a whole is dished. At the same time the nose 31 on the knock-out pin 36 and the nose 39 on the punch indent the blank centrally in the zone that is ultimately to be punched out to form the hole. The bending of the blank in the dishing action tends to force the metal of the blank adjacent the bottom face 34 of the die radially outward, since the bottom face of the blank tends to retain its original substantially perpendicular relation to the side walls of the blank. This radial force drives the metal strongly into the corners between the flat surfaces of the hexagon defined by the opening in the die 33, filling up these corners complete and sharply. This action is assisted by the nose 31 on the knock-out pin 36 which enters the adjacent end' face of the blank and tends to spread the same radially outward. This step produces the dished, or concavo-convex, blank 4|, illustrated in Fig. 4-a, having

indentations

42 and 43 formed by the

noses

31 and 39, and having well filled corners 44 adjacent the convex end face 45. At the completion of the operation illustrated in Fig. 4 the punch 38 is retracted and the blank 4| is ejected by the knock-out pin 36 into the transfer mechanism.

The blank 4| is then turned over and transferred into alignment with the die 46 mounted in the bed frame M. This die is formed with an opening having a hexagonal cross section correspending to the openings in the dies 33 and 28, and has a bottom wall 41 substantially perpendicular to the side walls 48 of the die opening. For making the usual type of nut having a washer face, the bottom wall 41 may be formed with a step 49. The blank 4| is upset into the die 46 by a punch carried by the reciprocating header slide 22. The punch 50 has a substantially fiat end face 5| surrounding a central nose 52, the face 5| being substantially perpendicular to the side walls 48 of the die opening. As the blank 4| is forced into the opening in the die 46 by the punch 50 the blank as a whole is bent to remove the concavo-convex shape imparted to it in the previous operation.

The concave face of the blank 4| is disposed adjacent the bottom wall 41 of the die 46, so that as the blank is flattened out by pressure of the punch against the convex face 45 the metal of the blank adjacent the bottom wall 41 of the die is forced radially outward. This action forces the metal strongly into the corners between the flats of the hexagon defined by the die opening so as to fill up these corners completely and sharply. The knock-out pin 53 is formed with a nose 54 which enters the recess 43 in the blank 6 4|, while the nose 52 on the punch 50 enters the recess 42 in the blank. The flat surface 5| of the punch 56 flattens the convex face 45 of the blank 4|. In the type of nut illustrated, a slight chamfer is ordinarily desired on the top face. To obtain this feature, the punch 50 is arranged so as not to-fiatten completelyv the convex face 45 of the blank, leaving a slight chamfer 55 at the corners adjacent this face.

At the completion of this operation the metal has been shaped into the blank 56 illustrated in Fig. 5a. The corners 51 between the flats of the hexagon are completely and sharply filled out through the axial length of the blank, except for the slight chamfer 55 which is preserved on the top face of the blank. A recess 58 constituting a washer face is formed on the opposite side of the blank. Central recesses 59 and 60 are formed in the top and bottom faces, respectively, of the blank.

After the completion of the upsetting operation illustrated in Fig. 5 the punch 50 is retracted and the blank 56 is ejected from the die into the transfer mechanism by the knock-out pin 53. The blank is again turned over and transferred into alignment with a punch die 6| mounted in the bed frame In and illustrated in Fig. 6. The die 6| is formed with a relatively shallow opening defined by side walls 62 and an annular bottom wall 63 surrounding an axial opening 64. The walls 62 and 63 are shaped to closely fit the top face of the blank 55 and the adjacent portions of the side walls of the blank.

The punching tool is carried by the reciprocating header slide 22 and is arranged to punch an axial hole through the blank, pull the blank out of the die 6| on the retracting stroke of the punch, and then strip the blank from the punch for discharge from the machine. In the illustrated embodiment the header slide 22 is formed with a bore 65 which slidably receives a plunger 66. The plunger 66 is fixedly mounted in position in any suitable way with respect to the bed frame In so that it remains stationary as the header slide 22 reciprocates. The bore 65 terminates in a wall 61 which separates the bore 65 from a bore 63 extending into the slide from the front face thereof. A punch 69 is secured in position in the wall 61 and projects beyond the front face of the slide 22. A sleeve 10 is threaded or otherwise suitably secured in the bore 68 and is provided with an opening 1| slidably fitting around an inner sleeve 12. The sleeve 12 is formed with an enlarged head 13 slidably fitting in the counterbore 14 formed in the sleeve 10. The sleeve 12 fits closely about the punch 69 and is arranged to be projected over the same to strip the blank therefrom. A plurality of rods 15 extend slidably through openings in the wall 61 and are arranged to abut at one end against the forward face of the plunger 66 and at the other end against the head 13 on the sleeve 12. The punch 63 is formed with a working end portion 16 connected to the punch by a relieved portion 11, so as to minimize friction.

When the blank 56 has been turned over and presented in alignment with the opening in the die 6| by the transfer mechanism, the punch 69 advances and enters the recess 60 in the bottom or washer face side of the blank 56. The blank 56 is first pushed into the recess in the die 6| so that its top face engages the annular bottom wall 63 and the adjacent portions of its side walls are confined by the side walls 62 of the die. The punch 63 continues to advance and shears the pressures.

wad 18 from the blank 55 to form an axial opening 19 therethrough. The punch first engages the wad l8 and starts the shearing action in the blank at a point lying in a transverse plane outside of the die GI. Thus the entire blank is permitted to swell slightly under the pressure of the punching operation, permitting free movement of the punch. Distortion of the blank is prevented, however, by the confining side walls 62 of the die 8|. punch has passed through the blank in the po' sition shown in Fig. 6, the metal of the blank springs back to its initial shape, and the wad I8 is discharged through the opening 84.

As the header slide 22 is retracted the pierced blank is withdrawn from the die 6| by the working end portion 16 of the punch 69, the blank being carried on the relieved portion 11. As the header slide approaches the limit of its rearward movement the rods 15, held stationary by the plunger 88 and sliding through the wall 81, engage the head 13 of the sleeve 12 and hold the sleevei|2 stationary while the header slide and the punch 69 continue to move rearwardly.

In this way the punch 69 is withdrawn into the sleeve 12, the front edge 80 of the latter engaging the pierced blank and stripping the same over the working end portion 15 of the punch 89. The finished blank 8| is then discharged from the machine and is ready for tapping.

In the preferred embodiment of this invention the blank l9 sheared from the elongated stock 8 is only slightly smaller than the opening in the die 28 so that the blank is properly guided and centered for the first blow. The opening in the die is preferably cylindrical in shape with a diameter substantially equal to the diameter across the flats of the hexagonal opening in the die 28. Thus the sized blank formed by the first operation is accurately guided and centered into the hexagonal opening in the die 28. The dies 33 and 46 are of substantially the same size and shape as the die 28, although a slight additional clearance may be allowed in each operation to facilitate the entry of the blank into the die. The metal displaced by the piercing

noses

31 and 39 in the operation illustrated in Fig. 4 and the

noses

52 and 54 in the operation illustrated in Fig. 5 flows into the blank so that the upsetting operations, in changing the external shape of the blank, need not reduce the axial height of the blank. In this way the amount of metal punched out of the blank in the wad I8 is reduced to a minimum.

The dishing operation on the blank illustrated in Fig- 4, and the subsequent flattening of the dished blank illustrated in Fig. 5, act as force multipliers on the metal of the blank adjacent the juncture of the side walls and bottom wall of the die openings so that the metal is caused to fill out the corners of the dies with a minimum of pressure applied to the front face of the blank by the punches. Thus accurate, well filled nut blanks are readily produced without excessive work hardening of the metal of the blank and without subjecting the tools and dies to excessive wad from one side of the blank with only the opposite side confined makes it possible to punch the blanks easily and accurately without distortion of the previously formed exterior surface After the working end portion 16 of the The operation of punching out the considerable detail in the making of nuts it will be understood that the invention is not limited thereto, but may be employed in making many other kinds of polygonal articles or portions of articles. The various features of the invention may be employed in the combination and sequence disclosed, or separately, or in other combinations and sequences. Many other variations and modifications thereof can be resorted to without departing from the scope of the invention as defined. in the following claims.

I claim:

1. The method of making polygonal articles comprising confining in a polygonal die opening a metal blank having end faces intersecting and substantially perpendicular to the sides thereof and upsetting said blank into concavoconvex form so as to force the metal of said blank against the polygonal wall of said die.

2. The method of making polygonal articles comprising upsetting metal stock into a blank having a rough polygonal outline and end faces intersecting and substantially perpendicular to the sides thereof, confining said blank in a polygonal die and upsetting said blank into concavoconvex form so as to force the metal of said blank against the polygonal wall of said die.

3. The method of making upset articles comprising confining in a die opening a blank having end faces intersecting and substantially perpendicular to the side edges thereof and upsetting said blank into concavo-convex form so as to force the side edges of said blank radially outward against the side wall of said die adjacent the convex face of said blank.

4. The method of making polygonal articles comprising upsetting metal stock to form a blank having a rough polygonal outline and end faces intersecting and substantially perpendicular to the sides thereof, confining said blank in a polygonal die and upsetting said blank into concavoconvex form so as to force the metal of said blank radially outward against the polygonal wall of said die adjacent the convex face of said blank.

5. The method of making upset articles comprising confining in a die opening a blank having end faces intersecting and substantially perpendicular to the side edges thereof and upsetting and dishing said blank into concavo-convex form so as to force the side edges of said blank radially outward against the side wall of said die adjacent the convex face of said blank.

6. The method of making polygonal articles comprising upsetting metal stock into a blank having a rough polygonal outline and end faces intersecting andsubstantially perpendicular to the sides thereof, and upsetting and dishing said blank into concave-convex form so as to force the metal of said blank radially outward against the polygonal wall of the die adjacent the convex face of said blank.

'7. The method of making polygonal metal articles comprising upsetting stock to form a blank having a rough polygonal outline and end faces intersecting and substantially perpendicular to the sides thereof, confining said blank in a polygonal die having a bottom wall disposed at an obtuse angle to its side walls, and upsetting the blank with a punch having a face portion substantially complemental to said bottom wall.

8. The method of making polygonal articles comprising shearing off a length of substantially cylindrical elongated stock, upsetting the sheared-01f length of stock to form a concavoconvex blank having a rough polygonal outline,

The method of making polygonal articles comprising shearing oil a length of substantially cylindrical elongated stock, upsetting the sheared-off length of stock to form a concavoconvex blank having a rough polygonal outline, confining said blank in a polygonal die and upsetting and bending-said blank in a direction to flatten the convex face thereof to force the metal of the blank radially outward against the wall of said die.

10. The method of making polygonal articles comprising shearing off a length of substantially cylindrical elongated stock, upsetting the sheared-oil length of stock to form a concavoconvex blank having a rough polygonal outline, confining said blank in a polygonal die and upsetting and flattening said blank to remove the concave-convex shape thereof and force the metal of the blank radially outward against the wall of said die adjacent the intially concave face of said blank.

11. The method of making metal articles comprising conflning a blank in a die opening. upsetting said blank by axial pressure into concavoconvex form so as to force the metal of said blank radially outward against the side wall of said die adjacent the face of said blank which becomes convex, and flattening said blank in a die opening to force the metal of said blank radially outward against the side wall of said die adjacent the opposite face of said blank.

12. The method of making polygonal articles comprising confining a blank in a polygonal die opening, upsetting and dishing said blank into concave-convex form so as to force the metal of said blank radially outward against the po ygonal wall of said die adjacent the face of said blank which becomes convex, and upsetting and flattening said blank in a polygonal die opening to remove the concavo-convex form thereof and force the metal of said blank radially outward against the polygonal wall of said die adjacent the opposite face of said blank.

13. The method of making polygonal articles comprising upsetting stock to form a blank having a rough polygonal outline, confining said blank in a polygonal die opening, upsetting said blank into concavo-convex form so as to force the metal of said blankradially outward against the po ygonal wall of said die adjacent the face of said blank which becomes convex, and flattening said blank in a polygonal die opening to force the metal of said blank radially outward against the polygonal wall of said die adjacent the opposite face of said blank.

14. The method of making polygonal articles comprising upsetting stock to form a blank having a rough polygonal outline, confining said blank in a polygonal die opening, upsetting and bending said blank into concavo-convex form so as to force the metal of said blank radially outward against the polygonal wall of said die adjacent the face of said blank which becomes convex, and thereafter flattening said blank in a polygonal die opening to remove the concavoconvex form thereof and force the metal of said blank radially outward against the polygonal wall of said die adjacent the opposite face of said blank.

15. The method of mamng polygonal articles comprising upsetting stock to form a polygonal blank having a rough polygonal outline in section and end faces substantially perpendicular to its side walls, confining said blank in a polygonal die opening, upsetting and bending said blank into concave-convex form so as to force the metal of said blank radially outward'against the polygonal wall of said die adjacent the face of said blank which becomes convex, and fiattening said blank in a polygonal die opening to remove the concavo-convex form thereof and force the metal of said blank radially outward against the polygonal wall of said die adjacent the opposite face of said blank.

16. The method of making nuts and the like comprising confining a blank in a polygonal die having a bottom wall disposed at an angle to its side walls different than the angle between the corresponding portions of the blank, upsetting the blank by pressing the same with a punch having a face portion substantially complementai to said bottom wall, removing the blank from said die, and thereafter punching an axial hole through said blank.

17. The method of making nuts and the like comprising confining in the side walls of a polygonal die, the side edges of a blank having a concave-convex shape, upsetting and bending said blank to flatten the concave face thereof and force the metal of the blank radially outward against the wall of said die, removing the blank from said die, and thereafter punching an axial hole through said blank.

18. The method of making nuts and the like comprising confining a blank in a polygonal die opening, upsetting said blank into concavo-convex form so as to force the metal of said blank radially outward against the polygonal wall of said die adjacent the face of said blank which becomes convex, flattening said blank in a polygonal die opening to force the metal of said blank radially outward against the polygonal wall of said die adiacent the opposite face of said blank, and thereafter punching an axial hole through said blank.

19. The method of making nuts and the like comprising upsetting stock to form a blank having a rough polygonal outline. confining said blank in a polygonal die opening, upsetting said blank into concavo-convex form so as to force the metal of said blank radially outward against the polygonal wall of said die adjacent the face of said blank which becomes convex, flattening said blank in a polygonal die opening to force the metal of said blank radially outward against the polygonal wall of said die adjacent the opposite face of said blank, and thereafter punching an axial hole through said blank.

20. The method of making nuts and the like comprising upsetting stock to form a polygonal blank having a rough polygonal outline in section and and faces substantiaily perpendicmar to its side walls, cumming said blank ii. a gonal die opening, upsetting and bending said blank into concavo-convex form so as to force the metal of said blank radially outward against the polygonal wall of said die adjacent the face of said blank which become convex, flattening said blank in a polygonal die 3"193 to remove the concave-convex form thereof and force the metal of said blank radially outward against limpolygonal wall of said die adjacent the opposite face of said blank, and thereafter punching an 8. 4 1 hole through said blank.

, cylindrical 21. The method of making metal articles comprising forming a blank having a side wall and end faces intersecting said side wall at peripheral corners, confining the sidewall of the blank in a die opening, applying axial pressure to said blank by tool and die surfaces initially engaging the same at the central portion only of one end face and adjacent the peripheral corner only of the opposite end face, and bending and upsetting the blank by such pressure about neutral axes within the axial length of the blank to bring the end faces into substantially full engagement with said tool and die surfaces without punching through the blank.

22. The method of making polygonal articles comprising upsetting a piece of metal into a blank having a side wall substantially polygonal in cross-section and end faces intersecting said side wall at substantially polygonal corners, confining the side wall of said blank in a polygonal die opening, applying axial pressure to said blank by tool and die surfaces substantially co-extensive with said end faces and initially engaging the blank at the center of one end face and adjacent the polygonal corner of the opposite end face while leaving the polygonal corner of the said one end face free to move radially inward and the center of said opposite end face free to move axially, and bending and upsetting the blank by such pressure about neutral axes with in the axial length of the blank to bring th end faces into substantially full engagement with said tool and die surfaces and force the polygonal corner of said opposite end face radially against the die.

23. The method of making metal articles comprising forming a blank having a side wall and end faces, one of said end faces being concave, confining said blank in a die having a side wall and a bottom wall with the peripheral portion of the concave end face of said blank engaging the bottom wall of said die and the central portion of said concave end face spaced from said bottom wall, and with the side wall of said blank engaging the side wall of said die adjacent said bottom wall, applying axial pressure to the central portion of the opposite end face of said blank and bending the blank by such pressure to bring said one end face into full engagement with the bottom wall of said die, thereby increasing the length of the peripheral portion of said concave end face and pressing the same against the die.

24. The method of making polygonal articles comprising shearing off a length of substantially elongated stock, upsetting the sheared off length to form a metal blank having a polygonal side wall and end faces, one of said end faces being concave, confining the side wall of said blank in a polygonaldie opening, applying axial pressure to said blank by tool and die surfaces initially engaging the blank at the peripheral portion only of the concave end face and the central portion only of the opposite end face, and bending the blank by such pressure to flatten said concave face and force the peripheral portion thereof radially against the die.

25. The method of making nuts and the like comprising forming a metal blank having a side wall and end faces, confining said blank in a polygonal die having a'bottom wall engaging the peripheral portion of one end face of the blank and spaced from the central portion thereof, applying axial pressure to the opposite end face of said blank to bend the blank into full engageupsetting the sheared off length into a blank having concavo-convex end faces and a peripheral side wall, confining the side wall of the blank in the side wall of a die with the concave end face of the blank having its peripheral portion engaging the bottom wall of the die and its central portion spaced therefrom, and upsetting and flattening said blank by axial pressure to force the metal of the blank radially outward against the side wall of the die.

27. The method of making polygonal articles comprising shearing off a length of substantially cylindrical elongated stock, forging the sheared ofi length into a blank having end faces and a side wall of rough polygonal shape, one of said end faces having an axial recess extending into but not entirely through said blank, said one end face including a concave portion radially outside of said recess, confining said blank in a die opening having a polygonal side wall, engaging said one end face with a die surface having an annular fiat portion forming sharp rightangled corners with the polygonal side wall of said die opening, said fiat portion initially engaging said one end face of said blank adjacent the periphery thereof with the remainder of said die surface spaced axially from said one end face, pressing said blank axially against said die surface, and flowing the metal of said blank by such pressure into full engagement with said annular fiat portion and with the sharp corners formed by said annular flat portion and the polygonal side wall of said die opening.

28. The method of making polygonal articles comprising shearing off a length of substantially cylindrical elongated stock, forging the sheared off length into a blank having end faces and a sidewall of rough polygonal shape, one of said end faces having an axial recess extending into said blank, said one end face including a con-.

cave portion radially outside of said recess, confining said blank in a die opening having a polygonal side wall, engaging said one end face with a die surface having one annular flat portion forming sharp right-angled corners with the polygonal side wall of said die opening and a depressed annular flat portion radially within and parallel to said one annular fiat portion and spaced axially therefrom by a substantially cylindrical shoulder, said one fiat portion initially engaging said one end face of said blank adjacent the periphery thereof with the remainder of said die surface spaced axially from said one end face, pressing said blank axially against said die surface, and flowing the metal of said blank by such pressure into full engagement with both said annular flat portions, said cylindrical shoulder and the sharp corners formed by said annular fiat portion and the polygonal side wall of said die opening.

29. The method of making polygonal articles comprising shearing off a length of substantially cylindrical elongated stock, forging the shearedofi length into a blank having end faces and a side wall of rough-polygonal shape, each of said end faces having an axial recess extending into but not entirely through said blank, one of said end faces including a concave portion radially outside of its recess, the opposite end face including a convex portion substantially aligned with said concave portion, confining said blank in a die opening having a polygonal side wall, engaging said one end face with a die surface having an annular fiat portion forming sharp right-angled corners with the polygonal side wall of said die opening, said fiat portion initially engaging said one end face of said blank adjacent the periphery thereof with the remainder of said die surface spaced axially from said one end face and pressing said blank axially against said die surface to flatten said convex portion and flow the metal of said blank into full engagement with said annular flat portion and with the sharp corners formed by said annular fiat portion and the polygonal side wall of said die opening.

30. The method of making polygonal articles comprising shearing off a length of substantially cylindrical elongated stock, forging the shearedoif length into a blank having end faces and a side wall of rough polygonal shape, each of said end faces having an axial recess extending into said blank, one of said end faces including a concave portion radially outside of said recess, the opposite end face including a convex portion substantially aligned with said concave portion, confining said blank in a die opening having a polygonal side wall, engaging said one end face with a die surface having one annular fiat portion perpendicular to the polygonal side wall of said die opening and abutting the same in sharp corners and a depressed annular flat portion radially within and parallel to said one annular flat portion and spaced axially therefrom, said one flat portion initially engaging said one end face of said blank adjacent the periphery thereof with the remainder of said die surface spaced axially from said one end face, pressing said blank axially against said die surface to flatten said convex portion, and flowing the metal of said blank by such pressure into full engagement with both said annular flat portions and said cylindrical shoulder and the sharp corners formed by said annular fiat portion and the polygonal side wall of said die opening.

31. The process of making polygonal nuts consisting of shearing off a length of substantially cylindrical elongated stock, confining the sheared off length in a substantially cylindrical first die and exerting pressure on the end faces thereof to size the same, confining the sized blank in a polygonal second die and exerting pressure on the opposit end faces thereof to flow the metal of the blank into a rough polygonal outline, confining the blank so produced in a polygonal third die and exerting pressure on the opposite end faces of the blank to form axial recesses in said end faces separated by an integral web in the blank and to further shape the polygonal side wall of the blank, then confining the blank in a polygonal fourth die, pressing one end face of the blank against a die surface having one annular fiat Portion forming sharp right angled corners with the polygonal side wall of said fourth die and a depressed annular surface radially within said one annular surface and spaced therefrom by a substantially cylindrical shoulder, flowing the metal of the blank by such pressure in the fourth die into full engagement with said annular flat portions, said shoulder, and the corners between said one annular fiat surface and the polygonal wall of said fourth die, and then confining the blank in a polygonal fifth die and punching an axial hole therethrough.

JOHN H. FRIEDMAN.

REFERENCES CITED The following references are of record in the file of this patent:

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