US2256796A

US2256796A - Manufacture of separable fastener elements

Info

Publication number: US2256796A
Application number: US282686A
Authority: US
Inventors: Soave John Giovanni
Original assignee: Waldes Kohinoor Inc
Current assignee: Waldes Kohinoor Inc
Priority date: 1939-07-03
Filing date: 1939-07-03
Publication date: 1941-09-23
Anticipated expiration: 1958-09-23

Description

J. G. SOAVE sept; 23, 1941.

MANUFACTURE OF SEPARABLE FASTENER ELEMENTS Filed July 3, 1959 2 Sheets-Sheet l INVENTOR dws/Af 5. 50,4 1/5 wh: Nm my.. i

WITNESS ATTORNEYS Sept. 23, 1941. J. G. SOAVE 2,256,796

MANUFACTURE OF SEPARABLE FASTENER LMENTS Filed July 5, 1959 2 Sheets-Sheet 2 jqy Wall- WITNESS INVENTOR .fw/V 6. 5 (1m/5 ATTORN EYS Patented Sept. 23, 1941 y 2,256,196 MANUFAc'runE or summum FAs'rENEn ELEMENTS John Giovanni Soave, Long Island City, N. Y., as-

signor to Waldes Koh-I-Noor, Inc., Long Island City, N. Y., a corporation of New 'York- Application July 3, 1939, Serial No. 282,686

420 Claims.

This invention relates to separable fastener structures of the type in which a pair of exible stringers or tapes have rows of interlocking elements attached along their adjacent edges, such elements being moved into and out of interlocking engagement by a slider movable along the rows. The interlocking elements of this type of fastener usually comprise a head portion which projects beyond the edge of the associated stringer and is provided on one side thereof with a locking projection and on its other side with a recess for cooperation with the locking projection of an adjacent interlocking element. Formed integrally with the head portion of each element are a pair of root or leg portions constituting clamping jaws by which the element is attached to the edge of a Stringer or tape. Experience has demonstrated that the form of element which functions most satisfactorily, enabling smooth and ready operation of the slider and minimizing wear on the slider, is one in which the leg portions or jaws thereof have straight outer surfaces along their lengths and transverse shoulders at their inner ends to enable the slider to obtain a rm grip on such'element while yet enabling it to move easily relative thereto'. One common method of making this form of element has been to'cut the elements from sheet material and the usual practice was to cut the elements so that their legs or jaws were in divergent relation and extended transversely to the longitudinal length of the strip, leaving the strip with a row of spaced substantially V-shaped apertures. 'I'his method of procedure involved a very substantial waste of material which constituted a large item in the cost of production of these units and in an effort to reduce this waste, manufacturers of slide fasteners attempted to devise other methods of cutting elements of the above described form from the strips of sheet metal. For example, one method devised by a manufacturer in this art, was to cut the elements in lengthwise position from a strip having a width equal to the width of the elements with their legs or jaws in closed i position, spreading the formed legs ofthe elements to enable them to be attached to the stringers or tapes and then returning the spread legs to approximately their cut form when properly associated with the stringer to which they were attached.

It is the object of the present invention to provide an improved method of manufacturing fastener elements having straight sides when attached to the stringers of the slide fasteners whereby waste of material and the steps of procedure are reduced to a minimum.

A further object of the invention is to provide a method of manufacturing interlocking elements whose construction is such that when they are attached to the stringers, they permit an easy and substantially noiseless movement oi the actuating slider, reduce the amount of wear on such slider and render the fastener structure extremely ilexible.

A better understanding of the objects and features of the invention will be obtained from a perusal of the following description taken in connection with the accompanying drawings in which Fig. l is an enlarged fragmentary front elevation of a slide fastener structure of the type to which the present invention relates, the slider and some of theI elements being shown in section to illustrate more clearly novel .details cf construction; Fig. 2 is a sectional view taken along the line 2-2 of Fig. 1; Fig. 3 is a horizontal sectional view of a portion of the die mechanism employed in producing the interlocking elements, the section being taken along the line 3-3 of Fig. 4; Fig. 4 is a vertical section taken along the line 4--4 of Fig. 3; Fig. 5 is a view similar to Fig. 4 illustrating the manner of cupping the strip to form the locking portion of the elements and shearing the fastener elements therefrom; Fig. 6 is an enlarged View of the recessed side of one of the fastener elements, the Stringer to which the element is attached being shown in section; Fig. 7 is a plan view of the metallic strip fromwhich the fastener elements are made and illustrates certain steps in the method of manufacturing the type of fastener element illustrated in Fig. 6; Fig. 8 is an enlarged view similar to Fig. l illustrating the method of manufacturing a modified form of fastener element; Fig. 9 -is a plan View of the element illustrated in Fig. 8 showing it attached to a Stringer; Fig. l0 is a side view of the parts illustrated in Fig. 9; Fig. 11 is a diagrammatic plan view illustrating the steps of manufacturing another modified form of fastener element; Fig. 12 is a plan view of the type of element illustrated in Fig. l1 showing it attached to the Stringer tape; Fig. 13 is a side view of the parts illustrated in Fig. 12; Fig. 14 is a horizontal sectional view of a portion of a mcdled form of die; Fig. l5 is an end plan view of the fastener element illustrated in Fig. 6 and Fig. 16 is a sectional view of the die mechanism illustrating another step in the movements of the cutting punch.

8 which are separated by a'x'ecess 9. Prior to the application of such element to its associated stringer, the

legs

1 and 8 extend divergently from the head portion as is indicated in dotted outline in Fig. 6, to facilitate insertion and attachment of the beaded or reenforced edge of the stringer tape between such legV portions. The head portion 6 of the element is provided on one of its ilat side faces with a projecting pin III and is provided at its opposite face with a complemental socket or recess II. The interlocking

elements

3 and 4 are formed from a flat strip or ribbon I2 (see Figs. 3 and 7) made of metal of the desired character for use in forming such units, such strip preferably being of substantially the same width as the width of the elements with their legs spread divergently from the head portions thereof as is indicated in Fig. 7 of the drawings.

In manufacturing theY interlocking elements from the strip or ribbon I21, the latter is advanced endwise through die mechanism with a step-by-step movement, each of the feeding steps being substantially equal to the length of a complete element. As is shown in Figs. 3 to 5 of the drawings, the die mechanism includes a die plate I3, a stripper plate I4 supported on the die plate I3 and having its operativeA portion spaced above the die plate I3 so as to form a channel I5 for insertion of the strip I2, a cupping punch I6 and a shearing punch I1. The cupping punch I6 and shearing punch I1 are connected at their upper ends by a head (not shown) which preferably is in-l tegrally formed with such punches and is actuated by any appropriate mechanism (not shown) to move such punches together at regular intervals. y

In the step-by-step movements of the strip or blank I2 towards the punches I6 and I1, it passes a rest or support I8 provided intermediate the ends of a transversely extending bar I9. The bar I9 is disposed in a transverse groove formed in the forward end of the die and is mounted at its ends on the spaced vertical pins 2l, 2I which extend downwardly on each side of an intermediate slide 22 positioned directly beneath and extending longitudinally of the die. The lower ends of the pins 2I, 2I are provided with

discs

23, 23 which are disposed in

annular recesses

24, 24 provided in the

bed walls

25 and 25 of the die and are seated on the

coiled springs

21, 21 positioned in such recesses 24, 24 (see Figs. 3 to 5). The

springs

21,21 are of sucient strength to normally maintain the pins 2|, 2l, the bar I9 and the support I8 in upward position with the end of the blank I2 resting on such support engaging the under surfaces of the stripper plate I4 to enable the feeding mechanism to advance the blank towards the punches as will hereinafter become more apparent. When the cupping punch I8 and the shearingl punch I1 descend to perform their operations on the strip, the shearing punch first engages the blank and lforces it against the tensionof the

springs

21, 21 down against the upper surface of the die in position to be operated upon by the punches (see Fig. 4). The bar I9 and the

discs

23, 23 by this operation are forced into the groove 20 and the

recesses

24, 24, respectively, the bar I8 and support I8 being constructed so that when the blank is fiat against the die. the upper surface of the support I8 is flush with the upper surfaces of the die, as can be seen in Figs. 4 and 5 of the drawings.

The cupping punch I8 in its movements passes through an aperture 28 in the stripper plate I4 and engages the blank to form the recesses or sockets II in the upper face of the blank and at the same time forces the metal material displaced thereby in the formation of such recesses into a die member disposed beneath the blank to form the outwardly projecting bosses or pins I0. In the embodiment illus-A trated, the working end of the cupping punch comprises a vertically disposed side face 29 which is substantially rectangularly shaped and forms the side 29' of the recess II (see Fig. 4). Extending from a point below the lower edge of the face 29 and inclining towards the latter at an angle of approximately 30 from the horizontal is the bottom face 30 of the die, the bottom edge of such face extending transversely to and through the central axis of the punch. The face 30 of the die forms the bottom 30' of the recess II. The inclined U-shaped side wall 3|' of the recess II (see Fig. 6) is formed by the substantially U-shaped face 3I of the punch, such face being shaped so that it inclines outwardly and upwardly from the bottom edge of the face 30 and in a direction opposite to the face 30 at an angle of approximately 37 from the horizontal and inclines outwardly and upwardly from the side edges of the face 30 at an angle of approximately 30 from the vertical.

The material displaced by the cupping punch I6 is forced by the latter into a recess formed by a portion of the side wall of a cylindrical recess 32 provided in the die I3 and the interior surfaces of a recess or notch 33 formed in the side upper edge of a plug or die member 34 positioned in the recess 32. The displaced material is thus formed into a locking pin IIJ which by reason of the form of the die is provided with a forward edge which extends substantially perpendicularly to the blank and curved inclined side and rear walls and is dimensioned so as to be capable of readily entering into a cooperating recess II of an adjacent element in the fastener and to loosely engage with the latter, as is illustrated in Fig. l of the drawings. The plugv 34 is preferably provided with an air hole 35 to facilitate the pin forming operation and the plug may be secured to the diein any suitable fashion as by pinning it to the die.

The shearing punch I1, as has been mentioned, moves downwardly simultaneously with the cupping punch I6 though slightly in advance of the latter so as to properly position the blank on the die for the cupping operation above described, as is shown in Fig. 4. As the punch I1 continues its downward movement it cuts out a complete fastener element by a severing cut made across the blanking strip I2 by its front cutting edge 36 and cuts made along the dotted lines 31 and 38, in Fig. 3 by its angularly disposed

rear cutting edges

39 and 40. The front cutting edge 38, as will be more clearly seen in Fig. 3 of the drawings is convexly shaped in its central portion and concavely shaped on each side of such central portion to form `the outer sides of the

jaws

1 and 8 and the outer side of the head 6 of the fastener element with the jaws spread as is indicated in `dotted lines in Fig. 6 of the drawings. The bottom face 44 of the punch I1 is slightly concaved downwardly at the forward end thereof so that the convexly shaped portion of the front cutting edge 36 is slightly advanced from the remainder of such edge (see Figs. 4 and 5). The angularly disposed cutting edges 31 and 38 form the rear edges of the

jaws

1 and 8. The punch I1 is preferably made wider than the Width of the strip I2 so that portions of the side edges of the strip are left untouched to provide the edge portions air is sent from a nozzle 45 into the passageway s to remove the two pieces of waste material 4I, 4I on the jaws of the fastener element (see Fig. 6). The angularly shaped side edges 42, 42 of -the punch ride in the vertically disposed angularly shaped grooves 43, 43 provided along the side edges of the aperture in the. stripper plate I4 through which thepunch I1 extends for a purpose which will be hereinafter more fully explained.

The die I3 is provided intermediate the punches I6 and I1 with a clearance hole 50 into which the projection or locking pin II) which was just previously formed by the punch I6 projects when the end of the strip I2 is advanced into position to be cut by the shearing punch I1. The clearance hole 50 is positioned with relation to the die hole 5I for the punch I1 so that the wall 52 formed therebetween is approximately equal to the space between the projection in the clearance hole 50 and the projection on the end of the strip to be cut. Thus the hole 50 and Wall 52 serve to accurately position the strip I2 for the shearing operation, with the forward upper edge of the inclined wall 3l' of the socket II at the end of the strip approximately directly over the top of the inner wall of the die hole 5I and under the convexly shaped central portion of the front cutting edge 36 of the punch (see Fig. 4). As the punch descends the central portion of the edge 36 engages with the strip I2 just in back of the socket II to initiallyshear the strip in such region as is shown more clearly in Fig. 16. During this portion of the travel of the punch the pressure exerted on the strip I2 along the initial shearing edge, compresses the material of the strip in the region of the socket Il, to slightly tilt the projection I0 from its initial position to the right, as viewed in Figs. 4, 5 and 16, to cause the central portion of the inclined wall 3l of the socket II to become slightly concaved, as can be seen more clearly in Fig. 1, and to compress the material of the strip in such region, as is shown in Fig. 15, the surface of the strip in engagement 'with the concaved portion of the bottom face 44 of the punch taking the form of such portion and becoming correspondingly convexly shaped.

Upon further downward movement of the punch i the complete element is sheared from the strip, the punch forcing the element through the die hole 5I and depositing it upon a slide 53 positioned below the die and just in front of the slide 22, as is shown vin Fig. 5.

The waste material sheared oi by the

cutting edges

39 and 40 of the punch I1 falls into a-passageway 54 extending transversely of the die, the rear surfaces of the punch I1 forming ya portion of the walls of such passageway, as can be seen more clearly in Fig. 3 of the drawings. Upon the sheared off by the punch I1. The valve of the nozzle is controlled by suitable mechanism (not shown) to cause a blast of air to be directed into the passageway 54 Just after the waste pieces have been sheared of! at the end of each shearing operation. The passageway 54 is slightly restricted in the regions where the waste pieces are cut off to direct the full force of the blast upon such'sheared pieces and to assure their being carried off. By reason of the interlocking of the sides of the punch I1 in the angularly shaped grooves 43, 43 of the stripper plate I4, air losses are reduced to a minimum and very little of the floirce of the blast is lost as it passes by the punch When the punches I6 and I1 are withdrawn, the strip I2 is forced up against the under surface of the stripper plate I4 by the spring pressed support I8 on which it rests to remove the projection I6 formed during such operation from the recess in the die block 34 and the previously formed projection positioned in the clearance hole 56 in the die I3 and to enable the strip to be moved forward in the next step-by-step movement of the feeding mechanism. The advance of the strip is just suiiicient to enable the projection formed in the last operation to enter into the clearance hole 56 when the punch I1 forces the strip I2 against the top surfaces of the die I3 on its next downward movement.

The completed element deposited on the slide 53 which is mounted between the side walls 25 and 26 of the die shoe or base, is advanced to the left, as viewed in Fig. 5, by the slide 53 and the slide 22. At the end of the movement of the slide 53, the slide 22 continues its movement to push the element along the top surfaces of the slide 53 to suitable mechanism for clamping the element to a tape. The forward edge 55 of the slide 22 is shaped similarly to the head of the element and completion of the shearing operation a blast of the slide 53 is provided with a central longitudinally extending groove 56 adapted to receive the projection I3 of the element so that the position of the 'element is positively controlled and maintained during the movement of the element to the clamping mechanism and during the clamping operations.

As a result of the clamping operation the outer concavely shaped

sides

36, 36 of the

jaws

1 and 8 of the element shown in dotted lines in Fig. 6 of the drawings; are straightened so that the outer side edges of the jaws are straight throughout and in parallel relation as is shown in full lines in such figure. The angularly disposed rear sides 31 and 38 of the

jaws

1 and 8 are also brought into position so that they are disposed at right angles to the

sides

36, 36 and form definitely defined transverse shoulders upon which the slider is enabled to obtain a firm grip, as is shown in Fig. 2 of the drawings. The chamfered sides 4I, 4I of the element enable the slider to move easily relative to the element and at the same time prevent unnecessary wear on the interior surfaces of the slider thereby assuring a perfect fit of the and 16 of the drawings. In both modified forms theA head of the element is made substantially in the shape of a semi-circle in order to reduce the width of the element to its smallest practical dimension while at the same time not weakening the element along the lines of juncture of such head portion with the jaws-thereof, i. e., along the lines between the points 51, 51 indicated in Figs. 8 and 11 of the drawings, where the maximum bending stresses take place in the formation of the element into its completed form. By forming the interior sides 58 of the jaws or legs of the elements so that when the elements are completed and clamped on the tapes, as is illustrated in Figs. 9 and 12, such interior sides and the interior sides of the head portions of the elements form a substantial-circle, the maximum amount of strength along the lines of juncture 51, 51 of the jaws with the head of the elements will be attained. In the element illustrated in Fig. 8, the radii of curvature of the interior sides of the jaws thereof are the same but are slightly different from the radius of curvature of the interior side 59 of the head portion of the element, being smaller than the latter so that a greater thickness of cord and tape will be enclosed between the jaws of the element. In the form of element shown in Fig. ll the radius of curvature of each of the interior edges of jaws is the same as the radius of curvature of the interior side of the head portion of the element so that when the element is clamped on a tape the interior sides thereof form a substantially perfect circle, as is shown in Fig. 12 of the drawings. Like the element shown in Figs. 1, 6 and 16, the elements illustrated in Figs. 8 to 13, have the exterior sides of the jaws formed concavely so that in their nal form after being clamped on the tape such edges will be straight throughout, with the outer side edges of the jaws of each element in parallel relation. In the two modifications illustrated, it is desirable that the faces 60 and 6 I of the recesses thereof adjacent to the outer edges of the head portions be substantially similar in shape to the latter and that the

surfaces

62 and 63 of the projections thereof be arcuately shaped, as is i1- lustrated. Like the first described form, however, the

faces

60 and 6| of the recesses thereof are concaved in the direction of their depths and the head portions thereof are reduced in thickness by the compressing thereof during the: shearing. operation, as has been previously explained. With the elements so formed and clamped to a pair of cooperating tapes, the fastener structure will have a maximum fiexibleness and can be bent readily without disturbing the interlocked condition of the elements, such elements by reason of the denser material at their working end portions being more resistant to wear.

While the foregoing describes certain desirable embodiments of the invention, it is to be understood that modifications and changes may be made without departing from the spirit and scope of the invention, as set forth in the accompanying claims. For example, instead of making the strip I2 just wide enough to produce the elepreviously described is not used. Instead a separating member 61 is provided in the die to form two diverging

channels

68, 68 through which the waste strips are led out of interference with the clamping mechanism and the tape. 'I'he waste strips 65, may be rolled up onto separate reels or otherwise taken care of.

I claim:

1. In a machine for making separable fastener elements having head portions and jaws, the combination with a die, of a shearing punch having a forward cutting edge of substantially the same contour as the outer edges of the head portion and jaws of an element and having a bottom face advanced in the region of the central portion of said front cutting edge whereby in the shearing operation of said punch the advanced portion of said bottom face initially engages the material of which the element is to be constituted and coacts with the die to compress said material so as to reduce the thickness thereof in such region.

2. In a machine for making separable fastener elements having head portions and jaws, the cornbination with a die, of a shearing punch having a forward cutting edge of substantially the samey contour as the outer edges of the head portion and jaws of an element with the latter in spread condition, and having a pair of angularly disposed rear cutting edges for cutting the inner ends of the jaws of the element, said punch having a bottom face advanced in the region ofthe central portion of said front cutting edge adapted to vinitially engage the blank from which the element is formed and compress the material of which the same is constituted so as to reduce the thickness thereof in such region during the shearing operation. a

3. In a machine for making separable fastener elements having head portions and jaws, the combination with a die, of a shearing punch having a forward cutting edge convexly shaped in its central portion and concavely shaped in ments of this invention, the strip may be made slightly wider, as is shown by the strip I2 in Fig. 14 of the drawings, in which case the waste material coming from the shearing punch will be in the form of two narrow

jagged strips

65, 65, as is shown in such figure. In using a strip such as I2' the shearing punch is modied at its side edges 66, 66 to produce chamfered ends on the fastener elements and the air blast discharge each side of such central portion and'adapted vto form the outer edges of the head portion and jaws of an element with the latter in spread condition, and said punch having bottom face concaved downwardly in the region of the central portion of said forward cutting edge so that said portion is advanced from the concavely shaped portion of said forward cutting edge.

4. In a machine for making separable fastener elements the combination of a die, a stripper plate adjacent to said die, the working surfaces of said die and stripper plate being spaced to provide an opening into which a metal strip may be inserted, means for normally holding the inserted end of the strip against the working face of said stripper plate, a cupping punch and a shearing punch associated with said die and stripper plate, said shearing punch being adapted to position the inserted end of the strip against said die prior to the engagement of the strip by said cupping punch.

5. In a machine for making separable fastener elements the combination of a die, a stripper plate adjacent `to said die, the working surfaces of said die and stripper plate being spaced to provide an opening into which a metal strip may be inserted, means for yieldably maintaining the inserted end of the strip away from the die and against the working face of said stripper plate, a cupping-punch associated with said die and stripper plate and means f or periodically pressing the inserted end of the strip against said die prior to the engagement of the strip by said cuppins punch- 6. In a machine for making separable fastener elements, the combination of a die, a stripper plate adjacent to said die, the working surfaces of said die and stripper plate being spaced to provide an opening into which a metal strip may be inserted, means for yieldably maintaining the inserted end of the strip away from the die and against the working face of said stripper plate, a cupping punch and a shearing punch associated with said die and Stripper plate and adjacent to one another, said shearing punch being advanced from said cupping punch and adapted in its movements to periodically press the inserted end of the strip against the tension of said yieldable means into contact with said die prior to the engagement of the strip by said cupping punch.

7. In a machine for making separable fastener elements, the combination of a die, a stripper plate adjacent to said die, the working surfaces of said die and stripper plate being spaced to provide an opening into which a metal strip may be inserted, a spring pressed support for the strip and adapted to normally maintain the inserted end thereof spaced from said die, a shearing punch associated with said die, a cupping punch positioned intermediate said spring pressed support and said shearing punch, said shearing punch in its movements towards said die being adapted to initially engage the inserted end of the strip and force it against the pressure of said spring pressed support against said die prior to the engagement of the strip by said cupping punch.

8. In a machine for making separable fastener elements, the combination of a. die, a stripper plate adjacent to said die, the Working surfaces of said die and stripper plate being spaced to provide an opening into which a metal strip may be inserted, a supporting member extending transversely to the path of movement of the strip, spring means supporting said member and adapted to normally position the latter so that the inserted end of the strip supported thereby is spaced from said die, a cupping punch associated with said die and stripper plate and means for periodically pressing the inserted end of the strip against the tension of said spring means into contact with said die prior to the engagement of the strip by said cupping punch, said die being provided with a recess formed to receive said supporting member when the latter is depressed by the pressing force of said last-mentioned means.

9. In a machine for making separable vfastener elements, the combination of a die plate provided with a pair of die holes positioned in spaced relation, a cupping punch associated with one of said die holes and adapted to punch recesses in the upper surface of metal strip and to force the displaced metal into the associated die hole, a shearing punch associated with the other of the die holes and adapted to coact with such hole to cut out fastener elements, said die plate being provided with a clearance hole intermediate said die holes for receiving the metal displaced by said cupping punch in a previous operation, and spring means for automatically moving the metal strip away from said die plate in the region of such holes after each cupping and shearing operation, said shearing punch being adapted to press the strip into contactwith said die plate prior to the engagement of the strip by said cupping punch.

10. In a machine for making separable fastener elements, the combination of a die plate provided with a. pair of die holes positioned in spaced relation, a stripper plate adjacentto said die plate and arranged with respect therewith to provide an opening into which a metal strip may be inserted, a cupping punch associated with the rst of said die holes in the direction of feed of the y strip and adapted to form recesses in the upper surface of said strip and to force the displaced metal into its associated die hole, a shearing punch associated with the other of the die holes for cutting fastener elements from .the strip, said die plate being provided with a clearance hole intermediate the die holes for receiving the metal displaced by said cupping punch in a previous operation, said clearance hole being positioned as to coact with such displaced metal to position the strip in predetermined relation with said shearing punch and its associated die hole and yieldable means supporting said strip and adapted to normally maintain the inserted end thereof spaced from said holes and in contact with said stripper plate, said shearing punch being arranged to periodically press the inserted end of the strip against the tension of said yieldable means into contact with said die plate prior to the engagement of the strip by said cupping punch.

11. In a machine for making separable fastener elements, the combination of a. die, a stripper plate having a portion spaced from said die plate to provide an opening into which a metal strip may be inserted,ra shearing punch and a cupping punch associated with -said die and stripper plate, a slide positioned below said die to receive the elements cut by said shearing punch and a second slide intermediate the die and said rstmentioned slide and movable relative to the latter.

12. In a machine for -making separable fastener elements, the combination of a die having a die hole, a cupping punch adapted to form recesses in the upper surface of a metal strip and to force the displaced metal into the die hole. the Working end of said cupping punch having a substantially vertically disposed face, an inclined bottom face and an inclinedgU-shaped face enclosing said bottom face and jning at its ends with said vertically disposed facef, whereby Athe recesses formed in the strip have a substantially vertically disposed wall, an inclined U-shaped wall andan inclined bottom surface, and means coacting with said die to compress the material of the strip around said U-shaped Wall and to deform the central portion of said U-shaped wall to cause it to become concaved in the direction of its depth.

13. In a. machine for making separable fastener elements, the combination of a die, a stripper plate adjacent to said die and having' a longitudinal surface spaced from said die to provide a longitudinally extending openinginto which a metal strip may be inserted, a channel formed by said die and stripper plate and extending transversely to said longitudinally extending opening, a shearing punch positioned at the juncture of said channel and opening and closing the connection therebetween when advanced towards said die, and means for delivering a blast of air into said channel after said shearing punch has advanced towards said die to carry away waste pieces of said strip cut on by said shearing punch.

14. The combination defined' in claim 13 in which the walls of said transverse channel are formed to provide a constricted opening on each side of said shearing punch.

15. The method of making separable fastener elements which comprises providing a at strip of metal material having a width at least as wide as the maximum transverse width of the desired element with the jaws thereof angularly disposed in spaced relation, progressively shearing the metal strip by successive transverse cuts which extend from one edge of the strip to the other and of a contour such as to form a recess in the end of the metal strip and at the same time cupping the metal of the strip at a point inwardly of and in the neighborhood of the end of the recess to provide a socket in one face and a pin projecting from the opposite face, and during each shearing operation compressing the metal of the element being cut in the region defined by the transverse cut to deform the material on the recessed side of the element into a convex shape.

16. The method of making separable fastener elements which comprises providing a flat strip of metal material having a width at least as wide as the maximum transverse width of the desired element with the jaws thereof spread at an angle to one another, progressively shearing the metal strip by successive transverse cuts which extend from one edge of the strip to the other and each of which has its central portion curved in an opposite direction to that of its end portions, and

by a succession of pairs of spaced angularly disposed cuts adjacent to and substantially normal with the end portions of the transverse cuts, and at the same time cupping the metal of the strip at a point inwardly of and in the neighborhood of each transverse cut to provide a socket in one face of the strip and a pin projecting from the opposite face, and during each shearing action deforming the metal of the element being cut in the region dened by said transverse cut to provide a convexly shaped surface portion on the cupped face of the strip and a concavely shaped end wall in the socket of the element.

17. In a machine for making separable fastener elements, the combination of a die plate provided with a pair of die holes disposed in alignment in the direction of feed of the metal strip to be cut, adjacently positioned and aligned cupping and shearing punches associated with said die holes, the working end of said shearing punch having a cutting edge adapted to make a transverse cut in the strip and shaped to form a recess in the cut end of the metal strip and having a bottom face portion advanced in the region of said cutting edge and of concaved shape to enable said shearing punch during its shearing stroke, to

compress the metal of the cut element in the region defined by the transverse cut into a convex shape and said cupping punch being associated with the first of said die holes in the direction of feed of the strip and adapted to be moved with said shearing punch to cup the metal of the strip at a point inwardly of the end of the recess cut by said shearing punch and to force the displaced metal into its associated die hole to provide a socket in one face of the strip and a pin projecting from the other face thereof.

18. A machine for making separable fastener elements such as is dened in claim 17, in which the cutting edge of said shearing punch is convexly shaped in its central portion and concavely shaped on each side of such central portion to form fastener elements having substantially semi-circularly-shaped head portions and jaw portions provided with straight parallelly-disposed outer sides, said shearing punch also including a pair of angularly-disposed rear cutting edges for cutting the inner ends of the jaw, the width of said punch along a line joining the points of juncture of said angularly-disposed edges with the ends of said transverse cutting edge being greater than the width of the metal strip to cause chamfered edge portions to be formed on an element intermediate the side and end edges of the jaws thereof. g

19. In a machine for making separable fastener elements, die mechanism including a channeled body having a feeding channel adapted to receive a metal strip and a Waste discharge channel disposed transversely to the feeding channel and communicating therewith, a female die member positioned on one side of said feeding channel and at the juncture of the latter with said discharge channel, a shearing punch positioned at the juncture of said @hannels and closing the connection therebetween when advanced into said female die member,- means for positioning the strip relative to said die member and punch so that a portion thereof extends into said dis'- charge channel and means for delivering a blast of air into said discharge channel after said shearing punchhas advanced toward said die to carry away waste pieces of said strip cut of! by said shearing punch.

20. The combination defined in claim 19 in which said shearing punch has a width greater than the width of said feeding channel and the side portions of said punch are slidably mounted in transverse grooves provided in the side walls of such channel, whereby air losses through said feeding channel are reduced to a minimum.

JOHN GIOVANNI SOAVE.