US1911180A - Method of and apparatus for making blanks - Google Patents

Description

y 0, 1933. w. D. CORLETT METHOD OF AND APPARATUS FOR MAKING BLANKS Filed Oct. 10, 1931 Patented May 30, 1933 UNll El isuaso D. COBLETT, OF CHICAGO, Ill-ILLINOIS, ASSIGIIOR TO STANDARD SCREW GOM- PANY, OF HARTFGR-D, GGNNECEIG'UT, A CORIPORA'EIGN OF NEW JERSEY METHOD OF AND APFARATUS FOE lt'IAKIIIG BLANIKS Application filed Gctober 10, 1931.

This invention relates to a method of and apparatus for forming blanks. As illustrated herewith, it has particular reference to the formation of blanks which may subsequently be made into screws, bolts, rivets, studs, or other generally similar parts, although it is not limited to that particular use.

It has for one object to provide a method of forming blanks having shanks which will be accurate in size and shape. Another object is to provide means whereby accurate blanks can be formed by dies from material which is relatively inaccurate in size, shape and finish at the time that it is used and from material of a class which has heretofore been considered unsuitable for use in the formation of accurate blanks. Another object is to provide means for increasing the die life by greatly reducing the wear on the forming dies. Another object is to provide a method of finishing a blank accurately to size by means of a die after it has been initially formed.

Other objects will appear from time to time in the specification and claims.

The method is illustrated in the following drawing, which shows diagrammatically the dies and the blank in several stages.

Figure l is a cross section illustrating the initial forming die. As shown this is a double ended die. A single ended die might be used;

Figure 2 is a cross section of the secondary forming or extruding die, showing a partially formed blank in position therein;

Figure 3 is a side elevation of one form of blank at an intermediate stage in its formation;

Figure 4 is a side elevation of the same form of blank upon completion;

Figure 5 is a side elevation of a different form of blank at an intermediate state corresponding to that shown in Figure 3. This form of blank is preferably made from the blank in the condition shown in Figure 3;

Figure 6 is a side elevation showing the blank of Figure 5 completed; and

Figure 7 illustrates a modified arrangement of the dies.

Serial No. 568,009.

Like parts are designated by like characters throughout the specification and draw- 111g.

The process in one manner may be applied to the forming of cap screws, bolts, rivets and upset products. Heretofore such products have been made on cold heading machines. They are usually made from continuous strips of wire which is cut ofi in any suitable manner in appropriate lengths. Such lengths are driven or otherwise inserted into a die which heretofore has been cylindrical. A portion of the end is allowed to protrude and sufficient pressure is exerted upon this, by striking 0r otherwise, in a single or multiple operation. to cause it to be enlarged laterally and thus producing a head. By this method, blanks such as those shown in Figure 4 may be formed. The process is relatively expensive, however, and the wear on the dies is great and their life is correspondingly short. I prefer, in my method, to use a die which is tapered. In ordinary practice this is a relatively slight taper. For purposes of illustration, it is necessary to greatly exaggerate the showing of this taper in the drawing.

In Figure 1 I show a die A, which is provided with a tapered bore A which may have a counter-sunk head forming portion A As shown the die is also provided with a tapered portion A and a counter-sunk head forming portion A". The die is thus in effect a double die. If desired, one end may be used and after it is worn the other end may be used. I could, of course, use a single die, solid or open dies. v

An appropriate length of wire is inserted in the tapered bore A Pressure is then exerted upon its end so that it is enlarged to form a head. The blank is then pushed or struck from the inner end through the perforation in the die and ejected. Because of the taper of the here A a very slight movement of the blank completely frees it from the die and it may thus be moved with a minimum of friction upon the parts. 7

As illustrated in Figure 3, the blank is shown after the completion of the operation above just described. It has a tapered shank portion B and a laterally extending head member B It is now ready for the second operation which will give it a true and accurate cylindrical shape, removing the taper. To accomplish this second step, I use an extruding die G. This die is provided with a straight portion C and is cut away, enlarged or relieved as at C It is preferably beveled as at C The diameter of the straight portion of the die C is greater than that of the end of the tapered shank member B. The latter may thus be easily inserted into the extruded die for a portion of its length. To complete the insertion of the blank, pressure is exerted. The blank is thus forced fully into the die to the position shown in Figure 2, and a portion indicated as at X is made straight or reduced to a true or accurate cylindrical shape. At this stage of the operation, the portion indicated at Y remains tapered and is of smaller diameter than the opening through the extruding die. The inner or tapered end of the blank is then contacted by a member D which may be of any suitable size or shape and operated in any desired manner or by any suitable mechanism, and the blank is moved in a reverse direction andout of the die. When it is so moved a re-extruding operation takes place and the straight portion C of the extruding die causes the metal to flow along and toward the tapered end and when the blank has been completely forced from the die it is found to have been made truly and accurately cylindrical throughout its length. I thus, by the several steps of my process, produce an accurate blank which is cylindrical and true to shape and dimension within extremely narrow tolerances and which is at once ready for threading or other operations in case any such are desired.

In the methods heretofore used in forming blanks, it has been necessary to have wire or stock which is itself made accurately and to close tolerances. It has, therefore, been considered necessary to use what is generally referred to as cold drawn wire. This wire is relatively expensive. In my method, particularly because of the extrud-. ing step, I reduce the blank to the proper shape within very close tolerances and I am able to use What is commonly called hot rolled wire which as furnished is less accurate in shape and size than cold drawn wire and which is appreciably cheaper.

For many purposes it is desirable to make blanks having shoulders intermediate their ends. Such a blank is shown in Figure 5, in an intermediate stage of its manufacture, and in Figure 6 it is shown completed.

Then it is desired to make a blank having a shoulder, the initial steps of the process are usually the same as those described above. A piece of wire of suitable length is inserted in the bore A of the die and by the steps above described is formed into a blank such as that shown in Figure 3. It is then forced through an extruding die such as that shown in Figure Q-but it is not forced entirely through the die. A die of suitable size is chosen and the blank is forced through the die only to the point E at which it is desired to form the shoulder. The primary extruding operation is thus carried out only for a portion E of the length of the blank. The blank is then forced from the extruding die and the re-extruding operation takes place and thus the portion of the blank up to the point where the shoulder is to be formed, is reduced to an accurate cylindrical. shape. A portion of the blank E still remains tapered as shown in Figure 5. Subsequently that tapered portion is forced into a second and somewhat larger extruding die and it is extruded and re-extruded to reduce that portion to cylindrical shape, as indicated in Figure 6, and thus the completed blank is formed with two cylindrical portions E and E one of larger size than the other, and the two separated by the shoulder E.

When any of the extruding processes is carried out, the excess metal all goes into the elongation. None is scraped off or in any way removed. It will be noticed from the drawing that the finished blank of Figure 4- is longer than the blank of Figure 3 and that the finished blank of Figure 6 is longer than the unfinished blank of Figure 5. The fillet-like portion shown adjacent the head of the blank in the forms illustrated in Figures 2, 4t and 6, may be allowed to remain, or if desirable, may be removed in any suitable manner.

No matter what; form of die I use, and no matter how the details of my method are modified, so long as I adhere generally to my method I am able to make extremely accurate blanks. In the past, even by separate machining of the separate parts, which is a relatively slow and expensive process, it has been impossible to hold the dimensions of such products with which I am dealing to tolerances closer than two or three thousandths of an inch. By my method, which is cheaper and more rapid, and which is accomplished with a tremendously increased die life, I am able to hold my product to tolerances of less than one-ten-thousandth of an inch.

Figure 7 illustrates a modified die arrangement by means of which a shouldered blank such as that shown in Figures 5 and 6 may be made. As thus shown, a die F, pro vided with a tapered bore F and a head forming depression F may be used. To this i tapered.

tion has at one end an inclined face G The perforation G is restricted as at G to pro- '*ide a cylindrical extruding portion of the die. H is a housing member provided with a perforation H corresponding generally in shape to the perforation G of tlie extruding die ant. in alignment with it. H is a mem ber mounted to be positioned within the perforation H and to move therein. It serves as a stop to limit the inward movement of the blank during the initial forming movement and serves also when it is driven further inward, as the forming movement is completed, to eject the blank.

In the use of the die arrangement shown in Figure '7, the stop member H is moved to the proper position and held there. A piece of wire of the proper length is then forced into the tapered portion and through it and partially through the extruding die,

iintil it strikes the stop H thus causing some extrusion of that portion of the memher which has passed through the extruding portion G of the extruding die G Once '1 the wire has come in contact with the stop H its further inward movement is stopped .nd further pressure on its outer or exposed end causes it to swell into the tapered portion of th die. After this operation is completed, the member which has forced the blank into the die is withdrawn or removed and the stop H is then forced farther inward or to the right, as shown in Figure 7, to eject the blank. In this movement the extruding of the inner portion of the blank is completed so that when it leaves the die it is generally in the condition shown in Figure 5, with its smaller end properly reduced to cylindrical shape and its thicker portion Subsequently the thicker tapered portion remaining is reduced to cylindrical shape in the manner described above.

It will be realized that whereas I have herewith shown and described a practical operative device, nevertheless many changes might be made in the size, shape, number and disposition of parts without departing from the spirit of my invention and I wish, therefore, that my showing be taken as in a sense diagrammatic.

The clearances, particularly within the extruding dies and associated parts, are of necessity exaggerated in the drawing. Otherwise the details would not be intelligible. The clearance of the member I-I within the bore or performation H and the clearance within the perforation G is exaggerated. Actually the clearance is relatively slight and the parts may be in contact with each other, but the diameter of the bore H and the perforation G is larger than that of the restricted or working portion G of the extruding die G. The same applies to the extruding die as shown in Figure 2.

I claim:

1. The method of forming a metallic blank, which includes the following steps: Acting upon a piece of metal of suitable size and shape and forming it into a tapered shank and thereafter changing said tapered shank into a cylindrical shank by first extruding a portion of said shank to reduce it to cylindrical shape and subsequently extruding the remainder of the shank and re ducing it to a cylindrical shape.

2. The method of forming a metallic blank, which includes the following steps: Acting upon a piece of metal of suitable size and shape and forming it into a tapered shank and thereafter changing said tapered shank into a cylindrical shank by first extruding a portion of said shank to reduce it to cylindrical shape and subsequently extruding in a reverse direction the remainder of the shank and reducing it to a cylindrical shape.

3. The method of forming a metallic blank which includes the following steps: Acting upon a piece of metal of suitable size and shape and forming it into a tapered shank and thereafter changing said tapered shank into a cylindrical shank by first extruding a portion of said shank to reduce it to cylindrical shape and subsequently extruding the remainder of the shank and re ducing it to a cylindrical shape of the same diameter as that of the first portion.

4. The method of forming a metallic blank, which includes the following steps: Acting upon a piece of metal of suitable size and shape and forming it into a tapered shank and thereafter changing said tapered shank into a cylindrical shank by first extruding a portion of said shank to reduce it to cylindrical shape and subsequently extruding in a reverse direction the remainder of the shank and reducing it to a cylindrical shape of the same diameter as that of the first portion.

5. The method of forming a metallic blank, which includes the following steps: Acting upon a piece of material, imparting to it a tapered shape and removing the taper by forcing the tapered portion through a die, first in one direction to remove a portion of the taper, and second in the reverse direction, to remove the remainder of the taper.

6. The method of forming a metallic blank, which includes the following steps: Acting upon a piece of generally rod-like material, imparting to it a tapered shape and removing the taper by forcing the tapered portion through a die, first in one direction to remove a portion of the taper, and second in the reverse direction to remove the remainder of the taper.

7 The method of forming a metallic blank which includes the following steps: Acting upon a piece of material, imparting to it a taered shape, and removing the taper by forcing the tapered portion through a die of greater diameter than the smallest diameter of the taper, first in one direction to remove a portion of the taper, and second in the reverse direction to remove the remainder of the taper.

8. The method of forming a metallic blank, which includes the following steps: iact' ig upon a piece of generally rod-like material, imparting to a tapered shape, and removing the taper in two steps, by forcing the tapered portion through a die of greater diamete than the smallest diameter of the taier, first in one direction, to remove a portion of the taper, and second in the reverse direction to remove the remainder ot' the taper.

9. The method of forming a metallic blank, which includes the following steps: Acting upon a piece of generally rod-like material, forming a head upon it and imparting to the rod-like portion tapered shape, and removing the taper in two steps, by forcing the tapered portion through die, of greater diameter than the smallest diameter of the taper, first in one direction to remove a portion of the taper, and second in the reverse direction remove the remainder of the taper.

10. The method tr forming a metallic blank which includes he following steps: Extruding a portion 0 a piece of metal of a suitable size and shape to form it into cylindrical shape, forming another portion or" said piece of metal into a tapered shanl' extruding the tapereo portion to reduce itto cylindrical shape.

11. The method of forming a metallic blank which includes the following steps: Ext-ruding a portion of a piece of metal of a suitable size and shape to form it into cylindrical shape, forming another portion of said piece of metal into a tapered shank, and subsequently extruding the tapered portion to reduce it to cylindrical shape.

12. The method of forming a metallic blank which includes the following steps:

Extruding a. portion of a piece of metal of a suitable size and shape to form it into cylindrical shape, forming another portion of said piece of metal into a tapered shank, and subsequently and separately extruding the tapered portion to reduce it to cylindrical shape.

13. The method of forming a metallic blank which includes the following steps: Extrudin a port-ion of a piece of metal of a suitable size and shape to form it into cylindrical shape, forming another portion of said piece of metal into a tapered shank, re-extruding the extruded portion and ex truding the tapered portion to reduce it to cylindrical shape.

14. The method of forming a metallic blank which includes the following steps Extruding a portion of a piece of metal of a suitable size and shape to form it into cylindrical shape, forming another portion of said piece of metal into a tapered shank, re-extruding the extruded portion and subsequently and separately extruding the tapered portion to reduce it to cylindrical shape.

15. The method of forming a metallic blank which includes the following steps: Extruding a portion of a piece of metal of a suitable size and shape to form it into cylindrical shape, and simultaneously forming another portion of said piece of metal into a tapered shank, extruding the tapered portion to reduce it to cylindrical shape.

16. The method of forming a metallic blank which includes the following steps: Extruding a portion of a piece of metal of a suitable size and shape to form it into cylindrical shape, and simultaneously torming another portion oi"- said piece of metal into a tapered shank, and subsequently and separately extruding the tapered portion to reduce it to cylindrical shape.

17. The method of forming a metallic blank which includes the following steps: Ext-ruding a port-ion of a piece of metal of a suitable size and shape to form it into cylindrical shape, and simultaneously forming another portion 01 said piece of metal into a tapered shank, re-extruding the extruded portion and subsequently and separately extruding the tapered portion to reduce it to cylindrical shape.

Signed at Chicago, county of Cook and State of Illinois, this 9th day of September 1931.

WEBSTER D. CORLETT.

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