US2165425A - Method of making recessed head screws - Google Patents

Description

- Julyl 11, 1939.

J. .1.ToMALls .I v2,165,425 l METHOD oF MAKING REcEssEu 111mmv Scnws original Filed Jan. 14; 1938 `2 sheets-sheet i J. .1. 'roM'ALls 2,165,425

original Filed Jan. 14, 193s z'sneets-sheet 2 v METHOD oF MAKING REcEssED HEAD scREws i f @qu o Q E w July 1l, 1939.

. Patentediuly 11. 1939 PATENT OFFICE METHOD oF MAKING ncEssEn HEAD SCREWS Joseph J. Tomalis,v Providence, R.I., assigner to American Screw' Company, Providence, R. I., a corporationof lthodewlsland AOriginal application Januaryv -14, 1938, Serial No. 185,036. Divided and this application June 10, 1938, Serial No.`213,013

2 Claims.

This invention relates to screw manufacture and more particularly to a method of manufacturing headed blanks for screws.` While the invention is not so limited, it is primarily intended for the manufacture of blanks for screws which have a recessed head such as disclosed in U. S. Patent No. 2,046,839. This application is a division of my copending application Serial No. 185,036, iiled January 14, 1938.

It is a general object of the invention to provide a novel and improved method of heading and recessing screw blanks formed from suitable Wire. Y'

More particularly it is an object of the invention to provide a method for making screws of the kind mentioned by first forming a screw blank having a head provided with a plurality of radial enlargements thereon and then punching a recess with radial groovesin the head, the grooves being punched in said radial enlargements of the blank.

By first forming a head with radial enlargements on 'the blank and then punching the recess so thatthe wings on the punch penetrate such enlargements, it has been found that the operationy of making screws of this kind is greatly improved and simplified. lieretofore it has been generally considered necessary to subject the screw blanks to a shaving4 operation after the recess is punched in the head. This was done to remove excess metal and produce a smooth surface on the head which would be free from fins or projections. The present method Iobviates the necessity of such shaving operation on the surface of the screw heads and also eliminates any danger of shaving away the rounded corners at the intersections of the recess with the surface of the head as described and claimed in U. S. Patent No. 2,084,079.

In carrying out the present method any suit- -able mechanism may be used for operating and controlling the punches, but I preferably employ the'mechanismillustrated in the accompanying drawings, which mechanism is claimed in mysaid copending application and which is herein described as one means of' carrying out the method of this application.

In said drawings:

Figure 1 is a longitudinal vertical section throughthe movable 'punch assembly and its fastenings showing also the stationary die. In this figure the upsetting operation ofthe ilrst punch is shown partially completed;

Figure 2 is a transverse vertical sectional view 55 of the punch assembly taken on the broken line (Cl. III- 2-2 of Figure 1, the ends of the punches being shown in elevation;

Figure 3 is a vertical section similar to Figure l showing the blank being carried into the stationary die by the first punch; 5

Figure 4 is a plan view partly in section of the die and punch portions of a screw heading machine with the moving parts and wire blank in the same position as in Figure 3;

Figure 5 is a horizontal section of the same partsl showing the completion of the first punch upsetting operation;

Figures 6 and 6A are respectively an enlarged end elevation and a partial longitudinal section of the first punch;

Figure 6B illustrates the shape of a blank after the first punch has operated thereon; and

Figure 7 is an enlarged end elevation of the second punch.

As customary in cold-heading machines for making screw blanks, the present arrangement includes a stationary part or anvil section I9 which opposes a reciprocating gate or cross-head II adapted to move toward and from as well as laterally of the stationary anvil I0. Mounted in the stationary part I0 is a fixed die member I2 having a longitudinal aperture therethrough to closely t the wire from whichthe screw shank or body is formedv and through which a knock-out pin I3 operates. -Another fixed die member I4 is also mounted in the stationary part I0 and through this die the wire W is intermittently fed by any well-known mechanism. The length of the blank to be used is determined by the wire stop S against which the end of the Wire comes in contact to complete the feed through the die I4. The cutting and carrying member I5 cooperates with the die I4 to cut ofi' a desired length of wire for a screw blank and carry it into position to be operated upon.

A punch holder I6 and a'punch slide Il are rigidly secured together as by bolts Ila and are v carried bythe 4cross-head II. The holder I6 is thus'arranged for reciprocating motion in two paths at right angles to each other. The first motion is parallel to the axis of the wire blank held in the die I 2 and results from the movement of the cross-head II in rectilinear guides (not shown) under the action of any suitable and well-known mechanism. 'I'he second path of motion is vertical to present successively the first punch I8 and the second punch I9 to a blank held in the die I2 and this motion results from the punch slide `I1 moving 1n asuitable dovetailgroove in the gate or cross-head II as 55 indicated in the drawings and as common in the art. under the action of the first motion.

The present invention is concerned with the method of forming screw blanks by two strokes of the gate or cross-head II, the first punch I8 being adapted to carry out the operation of forming the head and enlargements on the blank and the second punch I9 being arranged to form the recess in the head thus produced.

The position of the punch holder I6 with relation to the cross-head Il and the stationary die I2 is adjustable transversely by adjusting screws engaging bolts I'ia and vertically by adjusting studs and nuts 2l engaging the crosshead I I. The punch holder I6 may be 4positioned in this manner so that the hole in the first punch I8 and the nub on the second or nish punch i9 are properly aligned on the common axis of the screw blank indicated at 22 and the hole in the stationary die I8 at such time as each of the above punches is vertically moved into position to oppose the blank in the die.

'I'he first punch I8 is mounted in a socket in the holder I6 and this punch is made up of three portions or sections of-diierent diameters.

. The outer portion thereof closely ts and slides in a sleeve 23 secured in the socket of the holder I6 by a retaining pin 2li. 'I'he intermediate portion of the punch I8 is larger in diameter than the other sections and such intermediate section closely fits and slides in a bushing 25 tightly tted in the socket of the holder. The inner smaller portion of the punch I8 is surrounded by a spring 26 which bears at its rear end against the bottom of the socket in the holder and at its front end against the shoulder on the punch I8 formed by the enlarged intermediate portion thereof. Such enlarged intermediate portion of the punch and the sleeve 23 provide means for preventing the spring 26 from forcing the punch too far out of the holder I6. The punch I8 from its forward end to the shoulder thereon is machined flat on one side as indicated at I8A in Figs. 2 and 6, which forms a keyway through which extends a key or pin 21 vertically located mechanism.

ina hole in the sleeve 28. This pin'prevents rotary motion of the punch I8 at all times.

The punch I8 is apertured longitudinally, the outer or front end of this aperture being the same size as the aperture in the stationary die I2 and adapted to receive one end of the wire blank 22. The inner .or rear portion of said aperture is somewhat enlarged. A pin 28, which in effect forms part of the punch i8, is mounted in said aperture and the rear end thereof rests against or may be secured to a plug 28 tightly fitted in the holder I8, this plug being adapted to receive the shock and Wear of the pin 28, and the Asame may be replaced after being knocked out by blows through a removal hole at the rear thereof. Lubrication may be provided through the oil hole 30 to the various parts of the punch As willv be seen particularly from Figs. 6 and 6A, the forward face or end of the punch I8 is provided with a central recess arranged around the aperture therein. This recess is made up of a central part IBB and four spaced radial parts or depressions I8C which extend radially outwardly from said central part IBB and forwardly to the front face of the punch outside the central depression I8B. As will be seen, the parts IBB and I8C of the recess are all arranged within the confines of the end of the punch. The use of a Each of said punches acts on the blank' recess of this kind on the end of the punch including the radial depressions has been found to greatly facilitate the production of recessed screw heads without subsequent expensive operations to finish the head. The recess and radial depressions in the end of the punch result in the formation of a partially nished head as shown in Fig. 6B, which` has substantially the shape of the depression in the end of the punch and which includes four raised portions or lobes B produced on the top of the partially completed head by the radial depressions ISC on the punch. Said lobes or enlargements are shown somewhat exaggerated on the drawings to make the disclosure more clear. The function of these lobes or raised portions is important as will presently appear.

The second punch I9 is preferably movably mounted in a plug or adaptor 3i by a pin 32 after the manner disclosed in applicants prior Patent No. 2,082,085 and the adaptor is lrigidly secured in a socket in the punch holder I8, being held against rotation by the cross pin 33. The punch I9 is shaped 'to form in the head of the blank a recess of the shape shown in said Patent No. 2,046,839. To eect this result the punch is formed on the end thereof with a nub or projection having four radially arranged wings I9A surrounded by a depression ISB which produce the desired shape of recess.

As will be seen from the drawings the wings ISA are spaced and positioned to correspond with the radial depressions IBC in the first punch I8, that is each wing ISA extends radially in the same direction as the corresponding depression I8C. As the result of such arrangement, when the punch I9 is forced against the partially formed head on the blank 22, the wings ISA of the punch will engage and penetrate the enlarged portions or lobes B'on the head resulting from the depressions I8C. These lobes or enlargements B' provide additional metal at the required points so that when the wings IBA penetrate such enlargements and the metal is forced outwardly and laterally of the wings, sufcient metal is present at the proper points with the result that -the completed head is smooth and perfectly circular and any subsequent shaving operation thereon is'avoided. The end of the punch I9, including the wings ISA, is of such size that the recess formed thereby will be positioned entirely within the connesof the head formed on the blank by the first punch.

Referring further to the operation of the device, a length of wire sufllcient to form the screw blank 22 is cut off and 'carried into position in line with the holes in the die I2 and punch I8. The punch I8 is moved forward and one end of the blank enters the aperture in the punch I8, the other end being in line with the corresponding aperture in the stationary punch I2. The cutter and carrying member I5 recedes and the forward motion of the punch assembly continues as the punch I8 encloses an increasingly larger portion of the blank' until the punch pin 28 contacts the end of the blank and causes the blank to move partially into the die I2 as shown particularly in Figs. 3 and 4. The blank being thus supported at both ends the cutter and carrier I5 is caused to recede, as before noted, so as to permit the punch to further approach toward the die I2. The blank, actuated by the punch pin 28, travels into the die I2 until stopped by contact with the knockout pin I3, which is adjustable for different lengths of screws and which allows the blank to enter the die I2 a distance equal to the length of the screw desired. At that time the end of the punch I8 contacts the face of the die I2 and the punch now becomes a stationary part ,of the punch mechanism. Further forward motion of the punch holder I6 causes the spring 26 to be compressed and while being compressed, it prevents rebound of the punch I8 away from the die I2 until such time as the resistance of the metal being upset becomes greater thanl the spring pressure, as later explained. When the punch I8 becomes stationary againstthe die I2.V

shoulders or countersunk heads are to be pro- 1 duced).

'I'he spring 28 is so designed and constructed that as the punch p in 28 advances and at a point shortly preceding the completion -oi the forward stroke and unsetting operation, the rearward pressure exerted on the punch I8 by the metal being upset will momentarily become greater than the forward pressure of the spring 28 upon the -punch I8, with the result that the punch is caused to yield or move back a very short distance and this slight rearward motion permitsk the metal to now-or move out laterally in all directions which ensuresthat all parts of the recess and depressions in the front face of the punch will be supplied with metal and then as the gate orv cross-head continues its forward motion the punch 'I8having come in contact with the block II, the punch becomes a rigid part of the punch v assembly, and the punch is forced toward the die to complete vthe 'formation of the partially formed head. having thereon the lobes or enlargements B' as before described. After the first punch recedes the second punch I8I is raised and forced against the blank in the die to complete shaping of the head and to form the recess therein as before noted. When the gate again .moves back, the knock-out pin I3 is caused. by

suitable mechanism to eject the finishedV blank from the die I2.

` It will thus be seen that the foregoing mechanism operates to carry out the method of this invention by rst forming a head on a blank and simultaneously forming radial enlargements on the head and then forming a recess in the head by forcing into the same a punch provided with .radial wings so that the wings thereof engage the radial enlargements previously formed on the head.

Having thus described the invention, what is claimed as new. and desired to be secured by Letters Patent is:

l'. A method of making screw blanks of the type having a head provided with a recess therein having a central portion and four grooves extending radially therefrom, which method comprises subjecting the. blank to the action of a rst punch to form a partially completed head on the blank with four lobes -or enlargements extending radially on the top of the head, and then subjecting the blank to the action of a second punch having a central portion and four radial wings extending therefrom and forcing said wings of the second punch into said lobes or enlargements on the partially formed head to form the recess therein.

2. A method of making screw blanks of the type having a head provided ,with a recess therein having a central portion and a plurality of grooves extending radially therefrom, which method comprises forming a partially completed head on the blank with a plurality of lobes or enlargements extending radially on the top thereof, and then subjecting the blank to the action of a punch having a central portion and a plurality of radial wings arranged to Icorrespond with said lobes on the blank and forcing said wings of the punch into said lobes on the partially completed head to form the recess therein.

JOSEPH J.'romms.

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