US3446009A

US3446009A - Methods and apparatus for making staples

Info

Publication number: US3446009A
Application number: US644871A
Authority: US
Inventors: Nicholas William Cane; William Rushton
Original assignee: Lightning Fasteners Ltd
Current assignee: Lightning Fasteners Ltd
Priority date: 1966-07-11
Filing date: 1967-06-09
Publication date: 1969-05-27
Anticipated expiration: 1986-05-27
Also published as: NL6709538A; GB1158499A

Description

May 27, 1969 v WCANE ETAL 3,446,009

muons AND APPARATUS FOR MAKING STAPLES Filed June 9, 1967 //'1 1/54 7025 Mal /a A: Mum/v 644 5 United States Patent U.S. Cl. 5975 9 Claims ABSTRACT OF THE DISCLOSURE Method and apparatus for making Ushaped staples in which longitudinally spaced apertures are formed in a metal strip prior to severing staple blanks from the strip, the severed blanks then being bent along two bend lines to form the staples with edges of the apertures, forming staple edges and extending bases of staple prongs, lying between the bend lines.

BRIEF SUMMARY OF THE INVENTION Field of the invention This invention relates to methods and apparatus for making staples.

Description of prior art Staples are known having a web and tapering prongs located at opposite ends of the staple and formed integrally with the web. Such staples are used, for instance, as end stops of sliding clasp fasteners for the purpose of preventing sliders of the fasteners from being removed from series of fastener coupling elements.

In one method of producing staples, staple blanks are severed from a flat metal strip, the sides of which are notched to form prongs of staple blank ends. The staples in their finished form are U-shaped with prongs at the staple ends being located in the legs of the U-shape. However, one disadvantage in the use of this method is that the notching of the metal strip produces scrap metal which has been removed from between adjacent prongs. To overcome this disadvantage, in another method of producing staples, metal strip is cut transversely to form staple blanks with their pronged ends spaced apart in the longitudinal direction of the strip. Each cutting action upon the strip forms prongs on the trailing end of a blank being severed from the strip and simultaneously forms prongs at the leading end of a succeeding blank to be severed on a succeeding cutting action, so that the prongs of one blank are formed by metal removed from between the prongs of another blank during cutting.

In producing staples by this latter method, because a staple cutting punch and a staple bend means are provided at one station and by one tool, each blank is bent into a U-shape along bend lines which are necessarily provided upon the web. When a staple manufactured in this manner is secured to a woven article such as a fastener tape, because of the positions of the bend lines of the staple, the threads of the article which are located between the prongs become tightly bunched together in the junction regions of the prongs so that severing of the threads may result.

3,446,009 Patented May 27, 1969 Furthermore, the sizes of staples are dependent upon their strength requirements. When relatively large staples are used (for instance, upon fastener tapes) with a minimum number of prongs, the prongs may have such large widths at their bases that undesirable cutting of the threads of the tape results and apertures of undesirable size are formed in the tapes. On the other hand, if such larger staples are provided with more prongs having narrower bases, this results in more complex tooling and less space is provided at the prong bases between adjacent prongs which increases the bunching together of the threads.

SUMMARY OF THE INVENTION According to one aspect of the invention, a method of making staples comprises severing a portion from a metal strip along a first line of severance extending laterally of the strip through a first aperture provided in the strip to form two prongs one on each side of the aperture for one end of a staple blank with an edge of the aperture providing an edge between bases of the prongs, severing the staple blank from the strip along a second line of severance which extends laterally of the strip through a second aperture spaced longitudinally of the strip from the first aperture, the second line of severance forming two prongs, one on each side of the second aperture, at the other end of the blank with an edge of the aperture providing an edge between bases of the prongs, and forming the staple from the blank by bending the blank laterally at two bend line positions so that each end of the staple said edges between the prong bases is located either upon a bend line or between the bend lines.

Preferably, the strip is moved in step-by-step manner along a predetermined path through an aperturing station at which apertures are provided in succession and to a staple blank cutting station in which staple blanks are severed in succession from the strip, the severed staple blanks being bent at the two bend line positions while they are in the staple blank cutting station.

In one manner of performing the method according to the invention a set of two or more laterally spaced apertures are provided instead of each of the first and second apertures and each line of severance extends laterally of the strip and from aperture to aperture of its set to provide a plurality of prongs at each end of the blank, the prongs being separated by the apertures.

Preferably, in continuous operation, the second line of severance forms two prongs on the staple blank and also two prongs on a succeeding staple blank which are located one on each side of the second aperture.

Preferably also, the apertures are provided with ends which are formed with edges extending laterally of the strip between the prong bases.

According to a further aspect of the invention, a machine for making staples comprises a strip moving means operable for moving metal strip along a predetermined path in step-by-step manner through an aperture cutting station and then to a staple blank cutting station and for a predetermined distance during each step, an aperturing punch and a staple blank cutting punch located, respectively, in the aperture cutting station and staple blank cutting station and operable after cessation of each operation of the moving means to form an aperture in the strip and to cut a staple blank from the strip, the cutting punch having a cutting edge of shape and disposition such as to form a line of severance extending laterally of the strip to an aperture formed in the strip so as to provide two prongs one on each side of the aperture at the end of the blank being formed with an edge of the aperture providing an edge between bases of the prongs, and bend means for bending a severed blank into a staple, the bend means having two bend line positions, the distance between which is at least as great as the distance between adjacent apertures when formed in the strip, so that after bending of a staple, said edge between the prong bases is located either upon a bend line or between the bend lines of the staple.

Preferably, the bend means is located in the staple blank cutting station and comprises opposing surfaces located after the cutting edge of the cutting punch in the sense of direction of movement of the strip and a mandrel locatable between the opposed surfaces and around which a staple blank may be bent by the opposing surfaces when the mandrel is located therebetween. It is also preferable that the opposing surfaces are formed upon the cutting punch.

Preferably, the aperturing punch has a cutting edge having spaced-apart end cutting portions considered in the direction of the predetermined path, each end cutting portion extending transversely of said path.

The invention also includes a staple made by the method or machine according to the invention.

BRIEF DESCRIPTION OF DRAWINGS One embodiment of the invention will now be described by way of example with reference to the accompanying drawing in which:

FIGURE 1 illustrates a stage in the continuous production of four pronged staples for use as bottom stops for sliding clasp fasteners;

FIGURE 2 is a diagrammatic view partly in cross-section of parts of a machine employed in producing the staples;

FIGURE 3 is a cross-sectional view along lines III-III of part of the machine shown in FIGURE 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in FIGURE 2, a machine for producing staples from fiat metal strip and for fitting the staples to sliding clasp fasteners to form bottom stops comprises a staple blank cutting punch 1 located in a staple blank cutting station 2. The punch is reciprocable from an upper position shown in FIGURE 2 vertically towards and away from a mandrel 3 located beneath the punch, and a clenching anvil 4 for assisting in securing the staples to sliding clasp fasteners is located beneath the mandrel. The cutting punch, mandrel and clenching anvil are of conventional form and operate in conventional manner as will now be briefly described.

One end 5 of the punch is provided with a groove 6 of frusto-conical section as shown in FIGURE 3, a cutting edge 7 (FIGURE 2) forming the edges of the groove, cooperating during downward movement of the punch, with a complementary cutting edge 8 of a fixed die plate 9. A slot 10 extending upwardly from a cutting face 11 of the punch is provided to receive the mandrel 3. Opposing surfaces, provided by the sides 12 of the slot, and the mandrel form bend means for bending a severed blank into a staple. The relative sizes of the mandrel and slot are such as to allow a staple blank after cutting to be bent into U-shape at bend line positions determined by bend edges 3a of the mandrel with the legs of the U located between the mandrel and sides 12 of the slot. The mandrel is retractable in known manner to allow continuous downward movement of the punch after a staple bending operation to permit a clenching punch 13 slidably movably mounted within the slot 10 to co-operate with the clenching anvil to secure staples to sliding clasp fasteners. Relative movement of the individ l p r t k s place automatically in known manner to perform the cutting, bending and stapling operations. Strip moving means comprising a pair of feed rolls 14 is provided for feeding a length of metal strip in the direction of arrow A in FIG- URE 2 to the staple blank cutting station in step-by-step manner and for a predetermined distance during each step. The rolls are operable by a ratchet and pawl mechanism (not shown) automatically actuable in known manner after operation of the blank cutting punch and clenching punch and after their return to their upper positions shown in FIGURE 2.

In addition to the conventional features of the machine, the machine also incorporates an aperturing punch 15 located in an aperture cutting station 16 between the feed rolls 14 and the station 2. The aperturing punch 15 is reciprocable vertically and co-acts with a die aperture 17 provided in the die plate 9, the punch 15 being operable simultaneously with punch 1. The punch has a cutting edge 18 of rectangular cross-section with spaced-apart rectilinear end cutting portions 19 lying normal to the direction of movement of the strip along arrow A. The distance between the portions 19 is such that apertures formed in the strip after each movement of the strip along its path are spaced apart a distance less than the distance apart of band edges 3a of the mandrel.

In use, a slide fastenrs length 20 is provided with a plurality of pairs of series of interconnected coupling elements 21 attached to two tapes 22, each pair of series of elements being provided for one sliding clasp fastener and being separated along the tapes from a succeeding pair of series of elements provided for a succeeding fastener. As shown in FIGURE 2, the length 20 is fed intermittently in known manner across the clenching anvil 4 to have a staple secured as a bottom stop at one end of each pair of interconnected series of elements.

A strip 23 of metal for forming staples extends between the feed rolls 14 across the die plate 9 and beneath the punch 1 in the staple blank cutting station. As shown in FIGURE 1, the leading end 24 of the strip is provided with two prongs 25 for a staple blank, the prongs having been provided on a preceding cutting operation by the edge 7 of punch 1. The prongs have parallel opposing edges 26, and a laterally extending rectilinear edge 27 provided between the bases of the prongs, these edges being provided by part of the edges of an aperture previously formed in the strip by punch 15. An aperture 28 formed by punch 15 during the previous cutting operation by the punch 1, lies spaced away from the edge 27. Upon the length 20 being fed forward across the anvil 4 and coming to rest with the ends of a pair of series of elements located upon the anvil as shown in FIGURE 2, the machine is automatically operated in known manner to cause the

punches

1 and 15 to descend upon the strip from the positions shown in FIGURE 2 with punch 15 trailing behind punch 1. The punch 1 co-operates with the cutting edge 8 of the plate 9 to sever a staple blank 29 from the strip. During the cutting operation to form the staple blank, a line of severance 30 created by the action of the punch with the cutting surface 8 extends from the sides of the strip to the aperture 28 thus providing the blank 29 with two prongs 31 at its trailing end and also providing two prongs 32 at the leading end of the strip after removal of the blank. The prongs 31 are of tapered configuration and at their bases connected to the web 33 of the blank there is a transversely extending rectilinear edge 34 extending between the prongs and parallel opposing edge portions 35 extending from the edge 34. The prongs 32 are provided for the leading end of a succeeding staple and are of similar shape to the prongs 25 provided at the leading end of the blank 29, with part of the aperture 28 forming opposing parallel edges 36 of the prongs 32 and a transversely extending edge 37 between the bases of the prongs.

After the blank 29 has been severed from the strip, it is carried downwardly by the punch and is bent round the mandrel 3 to form it in known manner into a U-shaped staple 29a (as shown in chain dotted outline in FIGURE 2). The bend edgse 3a of the mandrel which are located a further distance apart than the distance between the edges 27 and 34 of the apertures cause the blank to bend along lines XX (FIGURE 1) with the edges 27 and 34 located between the lines. The mandrel is then withdrawn and punch 1 continues downwards to carry the staple between the surfaces 12 to a straddling position (FIGURE 2) over the coupling elements located on the anvil. The punch 1 holds the tapes 22 upon the anvil while punch 13 continues in its downward movement to cause the

prongs

25 and 31 to penetrate the tapes, the prongs then being bent in known manner by the upper surface of the anvil to secure the staple to the length 20 either across the elements or adjacent the elements and to provide a bottom stop for the pair of series of interconnected elements. While the staple is being secured in place, the punch descends through the strip 23 to form an aperture 38 in the strip which is spaced from aperture 28 a distance equal to the distance of aperture 28 from the edge 27. After this operation, the

punches

1 and 15 are withdrawn to their upper positions shown in FIGURE 2 after which the feed rolls 14 are automatically operated to feed the strip 23 in the direction of arrow A for the predetermined distance. The length is then fed forward to bring one end of the next succeeding pair of intermittent elements onto the anvil 4 in preparation for a next succeeding staple to be secured to the length to form a bottom stop.

In the next succeeding cutting operation by the punch 1, a line of severance (not shown) of similar shape to the line 30 passes through the aperture 38 to form two sets of prongs, one at the trailing end of the next succeeding staple blank and the other at the leading end of the strip material. During the next operation also, the punch 15 again descends to form another aperture spaced along the strip from the aperture 38 in preparation for the next cutting operation.

In staples made by the method and upon a machine according to the invention, the bend lines are not provided upon the webs of the staples as in the conventional method in which staples are formed from blanks with their ends spaced longitudinally of the metal strip. The threads of the material located between the prongs at each end of a staple made by the method and machine of the invention, therefore, are not bunched together in the region of the junction of the prongs with the web and no cutting of the threads takes place as may be the case in use of conventional constructions. Further, as the apertures formed by the method described above are of rectangular shape, there is a space provided between the prongs at each end of a staple whereas in conventional staple constructions the prongs approach very close together at their junction points with the web. These spaces provided by the method described further prevent the bunching together of the threads of the article located between the prongs. Moreover, because of the greater width provided between the prongs at their junctions with the web, the prong width is not so great at its base as is found in conventional staples of equal size and provided with the same number of prongs, so that the apertures formed by the prongs of staples made by the method described above must necessarily be smaller than the apertures formed in materials by the prongs of the conentional staples.

Furthermore, although wastage of metal strip results because of the material removed during forming of the apertures, there is less wastage than is found in the use of the conventional method in which metal strip is notched at its sides to form staple prongs.

In the embodiment described, the lines of severance form prongs at the leading end of the metal strip which converge as they extend towards the leading end. In an alternative arrangement, the prongs at the leading end diverge as they extend towards the leading end.

A further advantage as is apparent in the embodiment described is that staple blanks may be bent into U-shape while retained in the staple blank cutting station and using bend means, part of which forms part of the cutting punch, the 'finished staples having bend lines which do not lie across their webs.

We claim:

1. A method of making staples comprising severing a portion from a metal strip along a first line of severance extending laterally of the strip to form prongs, severing a staple blank from the strip along a second line of severance which extends laterally of the strip to form prongs, and bending the blank into a staple, wherein the improvement comprises providing a first aperture in the strip before severing along the first line of severance, providing a second aperture spaced from the first aperture before severing along the second line of severance, the first and second lines of severance extending, respectively, through the first and second apertures to form two prongs at each end of the blank one on each side of an aperture, with an edge of the aperture providing an edge between bases of the prongs, and forming a staple from the blank by bending the blank laterally at two bend line positions so that at each end of the staple, said edge between the prong bases is located either on a bend line or between bend lines.

2. A method according to claim 1 comprising moving the strip in step-by-step manner along a predetermined path through an aperturing station at which apertures are provided in succession after movement of the strip and to a staple blank cutting station in which staple blanks are severed in succession from the strip, the severed staple blanks being bent at the two bend line positions while they are in the staple blank cutting station.

3. A method according to claim 1 wherein the second line of severance forms two prongs on the staple blank and also two prongs on a succeeding staple blank which are located one on each side of the second aperture.

4. A method according to claim 1 wherein the apertures are provided with ends which are formed with edges extending laterally of the strips between the prong bases.

5. A machine for making staples comprising a strip moving means operable for moving metal strip along a predetermined path in step-by-step manner through a staple blank cutting station, a cutting punch located in the cutting station for severing staple blanks from the metal strip, and bend means disposed along the predetermined path for bending severed blanks into staples wherein the improvement includes an aperturing punch with an aperture cutting edge located in an aperturing station between the strip moving means and the cutting station, the aperture punch and cutting punch being operable after each operation of the moving means to form an aperture in the strip and to form a staple blank from the strip, the cutting punch having a cutting edge to form a line of severance extending to an aperture formed in the strip to provide two prongs one on each side of the aperture at an end of the blank being formed with an edge of the aperture providing an edge between bases of the prongs, and the bend means having two bend line positions to produce bend lines on a staple blank to make a staple, the distance between the bend line positions being greater than the distance along the cutting edge of the aperture punch in the direction of the predetermined path to locate said aperture edges at each end of a staple between bend lines of the staple.

6. A machine according to claim 5 wherein the bend means is located in the staple blank cutting station and comprises opposing surfaces located after the cutting edge of the cutting punch in the sense of direction of movement of the strip, and a mandrel locatable between the opposed surfaces and around which a staple blank may be bent by the opposing surfaces when the mandrel is located therebetween.

7. A machine according to claim 6 wherein the opposing surfaces are formed upon the cutting punch.

8. A machine according to claim 5 wherein the aperturing punch has a cutting edge having spaced-apart end cutting portions considered in the direction of the predetermined path, each end cutting portion extending transversely of said path.

9. A machine according to claim 5 wherein a die plate extends from the aperture cutting station to the blank cutting station, the die plate having a die aperture and a cutting edge to cooperate, respectively, with the cutting edge of the aperturing punch and the cutting edge of the cutting punch.

8 References Cited UNITED STATES PATENTS 322,997 7/1885 Thayer 5977 786,504 4/1905 Lewis 59--72 2,431,812 12/1947 Lang 5972 CHARLES W. LANHAM, Primary Examiner.

G. P. CROSBY, Assistant Examiner.

US. Cl. X.R. 59-77; 8549