US3763546A

US3763546A - Method and apparatus for producing gaps in slide fastener chains

Info

Publication number: US3763546A
Application number: US00221187A
Authority: US
Inventors: M Peliman
Original assignee: CARBIDE FORM GRINDING Inc
Current assignee: CARBIDE FORM GRINDING Inc
Priority date: 1972-01-27
Filing date: 1972-01-27
Publication date: 1973-10-09
Anticipated expiration: 1990-10-09
Also published as: GB1389701A; FR2173908B1; DE2248966A1; DK135876C; IT970071B; SU520889A3; CA972935A; FR2173908A1; DK135876B

Abstract

A method and apparatus for producing a gap in a slide fastener chain having a pair of tapes carrying along adjacent inner longitudinal edges thereof continues coils attached to the tapes and having interengaged coupling portions, in which the coils are attached to the tape so that the coils are covered at one side thereof by the tapes. The tapes are clamped at the desired location of the gap in the region of outer longitudinal edges thereof and then deflected in direction transverse to the plane in which they are located between the clamped positions thereof and the coils connected thereto to thereby pull the inner longitudinal edges apart and to thus expose interengaged coupling portions of the coils, whereafter the coils are cut between the pulled apart inner edges of the tapes. The cut coils are then removed from the tapes by pulling the cut coils out of the threads by means of which they are connected to the tapes.

Description

Oct. 9, 1973 United States Patent [191 Perlman v METHOD AND APPARATUS FOR Primary Examiner-Thomas H. Eager Attorney-Michael S. Striker PRODUCING GAPS IN SLIDE FASTENER CHAINS [57] ABSTRACT 'A method and apparatus for producing a gap in a slide [75] Inventor: Morris Perlman, Brooklyn, N.Y.

[73] Assignee: Carbide Form Grinding, Inc.,

Brooklyn, N.Y.

fastener chain having a pair of tapes carrying along adjacent inner longitudinal edges thereof continues 2 Fl 2] led Jan 1972 coils attached to the tapes and having mterengaged coupling portions, in which the coils are attached to [2|] Appl. No.: 221,187

the tape so that the coils are covered at one side thereof by the tapes. The tapes are clamped at the desired location of the gap in the region of outer longitudinal edges thereof and then deflected in direction transverse to the plane in which they are located between the clamped positions thereof and the coils con- DM 5 7 w 7 O WO H3 92 2BOOO 4 0 0 0 4 I121 91 .M 2 u .9 m3 m "2 m m m h n c r u a u e n S L ll C d s m UhF HUN 555 [[l nected thereto to thereby pull the inner longitudinal [56] References Cited UNITED STATES PATENTS edges apart and to thus expose interengaged coupling portions of the coils, whereafter the coils are cut be- 29/408 tween the pulled apart inner edges of the tapes. The

Takamats 29/2075 D cut coils are then removed from the tapes by pulling 29/408 the cut coils out of the threads by means of which they are connected to the tapes.

2,987,809 6/1961 Burbank 3,6l1.538 10/1971 3,611.545 l0/l97l 17 Claims, 9 Drawing Figures PATENTEI] URI 9 I973 SHEET 2 BF 4 PAIENIEU 9'973 3.768.546

sum u m 4 E f 5 /j 5 3/ i 5 T/ 7 T Y/ Tf i, i Li i H 29 Li Li 1 5; L I I 47" l 1 m I i I. H 46 7: :J I I BACKGROUND OF THE INVENTION In the mass production of slide fasteners it is common practice to produce a more or less endless slide fastener chain composed of a pair of tapes having along adjacent inner longitudinal edges thereof interengaged coupling elements which, lately, are preferably made from coils of plastic filaments sewn to the tape and having coupling portionswhich are interengaged so as to connect the two stringers of the slide fastener chain to each other. Such a chain is then further processed to make individual fasteners of desired length. To convert the endless slide fastener chain into finished individual slide fasteners of the desired length suitable for application to a garment or the like, it is necessary to cut away a given length of interengaged coupling elements or interengaged coil filaments at desired intervals toprovide an element free gap in the continuous chain. Subsequent thereto, the chain is cut across the gap to provide a slide fastener of a desired length having opposite ends free of coupling elements.

As mentioned before, the interengaging coupling elements on the two slide fasteners stringers are perferably' made of continuous substantially helical coils of filamentary material sewn or woven to one longitudinal edge of the tape and-a continuous slide fastener chain is produced by pulling up two stringers, that is by interengaging the coupling portions of the coils fastened to two tapes. The coils are preferably produced from plastic filaments such as nylon or the like.

In order to produce gaps in such acontinuous slide fastener chain, the convolution of the coils are severed by a thin blade-like punchhaving a length corresponding to the length of the gap to be produced, but it is of utmost importance that during severing of the convolu tions of the coils the tape is not damaged.

Special difficulties are encountered in this respect when the slide fasteners to be produced are of the type which is generally called in the trade covered slide fastener," that is, in slide fasteners in which the coiled filaments are connected to the tapes in such a manner that when the coupling portions of the coils on the two tapes are interengaged, the coils are completely covered at one side thereof by the tapes, that is, when the adjacent edges of the two tapes abut against each other.

In order to cut the filament coils in such a covered slide fastener chain without damaging the tapes, it is evidently necessary to pull the two tapes laterally apart so that at least portions of the coils become exposed between the thus spacedinner edges of the tapes, but this pulling apart of the tapes has to be made in such a manner so as not to disengage the interengaged coupling portions of the coils. This pulling apart of the tapes before severing the coils has therefore to be made in a very exact and controlled manner inorder to assure that the inner edges of the two tapes are pulled apart for a distance so that the cutting punch may move be tween these edges withoutdamaging the tape and care has to be taken that the tape is also not damaged by the pulling apart operation and that the interengaged portions of the coils do not become disengaged before the coils are out.

Another problem residing in providing gaps incontinuous slide fastener chains is to properly remove the severed convolutions of the coils in their entirety from the tape, that is without leaving any remnants of the severed coils still attached by the threads to the tapes.

Various attempts have already been made to solve the above-pointed out problems, but none of these attempts have lead to completely satisfactory conditions.

SUMMARY OF THE INVENTION It is an object of the present invention to provide for a method and apparatus for producing gaps in a continuous slide fastener chain, and more specifically in a continuous slide fastener chain of the covered type in which the coupling elements are formed by continuous coils of filamentary material attached to the two tapes of the chain in such a manner that in the interengaged position of the coupling portions of the coils the inner longitudinal edges of the tapes abut against each other.

More specifically, it is an object of the present invention to provide for a method for producing gaps in such slide fastener chain in which prior to the cutting of the convolutions of the coiled filaments the two tapes of the chain are pulled transversely apart in an exactly controlled manner so that the blade-like punch for cutting the filament coils may move past the pulled apart inner edges of the two tapes without damaging the tapes during the cutting operation and so that during the pulling apart of the two tapes the coupling portions of the coiled filaments will remain engaged while at the same time no damage is caused to the tapes by the pulling apart operation itself.

It is a further object of the present invention to provide for a method in which the coil convolutions, after being severed, can be removed in their entirety from the tapes to which they are attached by threads.

It is an additional object of the present invention to provide for an apparatus by means of which the aforementioned operations can be carried out in efficient manner and in which the apparatus is composed of relatively few and simple parts so that it may be manufactured at reasonable cost and will stand up perfectly under extended use.

With these object in view, the method according to the present invention, of producing a gap in a slide fastener chain having two tapes carrying along adjacent inner longitudinal edges continues coils attached to the tapes and having interengaged coupling portions and in which the coils are attached to the tapes so that the coils are covered at one side thereof completely by the tapes, comprises the steps of clamping the tapes in the region of outer longitudinal edges thereof at the desired location of a gap, deflecting the tapes between the thus clamped outer longitudinal edges and the interengaged coupling portions to thereby pull the inner longitudinal edges of the tapes apart in a controlled manner and to expose the interengaged coupling portions, cutting the coils between the pulled apart inner longitudinal edges of the tapes for a distance corresponding to the desired length of the gap, and removing the cut coils from the tapes.

Since the coils are usually attached to the tapes by sewing or weaving, the step of removing the cut coils from the tapes comprises the step of pulling the cut coils out of the threads which attach the coils to the tapes.

In order to completely remove the severed coils from the tapes it is essential that each of the convolutions of the coils is cut only at one side thereof and this is preferably done by engaging the coils at said one said by a pair of transversely spaced cutting edges of a die and at the other side thereof by an endface of a punch adapted to move with clearance between the cutting edges, whereafter the die and punch are moved relative to each other so that the punch passes between and beyond the cutting edges. The step of pulling the cut coil convolutions out of the thread means by means of which they are attached to the tape comprises the step of pinching the cut coils during movement of the punch beyond the cutting edges, between side faces of the punch and opposite faces of the die spaced from the side faces a distance smaller than that of the spacing between the cutting edges. The thus pinched or squeezed portions of the severed coils are then dragged by the moving punch along and thus removed in their entirety from the threads which fasten the coils to the respective tapes.

The apparatus for carrying out the above method preferably comprises a die having a locating face on which a portion of the chain which is to be formed with the gap is adapted to rest, and pressure pad means arranged opposite and movable toward and away from the locating face of the die. The die and the pressure pad means have first cooperating means to clamp the tapes of the chain resting on the locating face in the region of outer longitudinal edges thereof and second cooperating means for deflecting a portion of each tape out of the locating face so as to pull the adjacent inner longitudinal edges of the tapes apart in a controlled manner and to thus expose the interengaged portions of the coils. The apparatus includes further a punch movable between the pulled apart inner longitudinal edges of the tapes and cooperating with cutting edges on the die for cutting the coils without cutting the tapes for a distance corresponding to the desired lengths of the gap and for pulling the thus severed coil convolutions during further movement of the punch out of the thread means by means of which the coils have been attached to the respective tapes.

The above-mentioned first cooperating means for clamping the tapes in the region of the outer edges thereof may comprise a pair of outer side faces of the die extending transverse to the locating face and a pair of cooperating faces on the pressure pad extending respectively substantially parallel to the side faces spaced therefrom a distance to clamp outer portions of the tape between the side faces and the cooperating faces during movement of the pad towards the die, or the first cooperating means may comprise an auxiliary pressure pad carried by the main pressure pad and having faces substantially parallel and facing outer portions of the locating face, and biasing means for yieldably biasing the auxiliary pressure pad toward the locating face so that outer longitudinally extending portions of the tape are clamped between the faces of the auxilairy pressure pad and the portions of the locating face during movement of the pressure pad toward the die.

The second cooperating means for deflecting the portion of each tape out of the locating face may comprise a pair of spaced longitudinally extending grooves in the die and corresponding longitudinally spaced ridges on the pressure pad adapted to penetrate with clearance into the grooves, respectively, during movement of the pressure pad towards the die.

The die is preferably provided with a central longitudinal slot having a length substantially equal to that of the gap to be produced and being defined by a pair of substantially parallel inner faces extending substantially normal to the locating face and being spaced from each other so that the punch may move with clearance between the aforementioned inner faces, and a pair of cutting edges to opposite sides of the slot facing the pressure pad and being spaced from each other a distance greater than that of said inner faces. The punch preferably has at least over a major portion of its length a rounded bottom edge and a pair of side faces parallel to the inner faces defining the slot in the die, and the clearance between the side faces of the punch and the cutting edges of the die is substantially twice the clearance between the side faces of the punch and the inner faces of the die which define the slot so that the punch during its relative movement with respect to the die will cut the filament coils only at one side thereof while during further movement of the punch into the slot of the die the severed filament portions will be squeezed between the side faces of the punch and the faces which define the slot in the die so that during downward movement of the punch into the slot the severed coil convolution will be pulled out of the attaching threads.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial front view of the apparatus according to the present invention and showing the apparatus in a starting position.

FIGS. 2 and 3 are partial front views of the apparatus shown in FIG. 1 and respectively showing the position of the pressure pad as it approaches the die to clamp the two tapes in the region of the outer longitudinal edges thereof and to subsequently deflect the tapes so as to pull the inner edges apart and to expose part of the coils;

FIG. 4 is an enlarged sectional view illustrating the relative positions of the die, the pressure pad and the punch at the start of the cutting operation of the coils;

FIG. 5 is a similar sectional view illustrating the punch in a further advanced position in which the punch starts pulling the severed convolutions of the coils out of the threads by means of which they are attached to the tapes;

FIG. 6 shows the punch in a further advanced position in which part of the severed filaments are squeezed between side faces of the punch and corresponding side faces of the slot in the die so that the severed convolutions of the coils are completely pulled out from the thread during advance of the punch;

FIG. 7 is a partial top view of the die;

FIG. 8 is a bottom view of the blade-like punch; and

FIG. 9 is a partial front view of a modification of the apparatus shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawing and more specifically to FIG. 1 of the same, it will be seen that the apparatus according to the present invention comprises a die 1 composed of two-mirror-symmetrical parts la and lb which are connected to each other in a manner as will be described later on in further detail and a pressure pad means 2 arranged above the die 1 movable toward and away from the latter. The pressure pad means 2 preferably comprises support means 3 which may be composed, as shown in the drawing, of an upper block 6 and a lower block composed of two mirror symmetrical parts 7a and 7b connected to each other by a plurality of transversely extending screws 8 and abutting with the top face thereof against the bottom face of the upper block 6 and connected to the latter in any convenient manner by screws or the like, not shown in the drawing. The pressure pad means 2 further comprises the actual pressure pad 4 composed also of two mirror symmetrical halves 4a and 4b connected to and guided for movement relative to the support means in vertical direction by a plurality of preferably cylindrical rods 9, only two of which are shown in the drawing, which are provided at the lower ends thereof with male screw threads so as to be threadily connected in correspondingly threaded bores formed in the pressure pad parts 4a and 4b. The rods 9 are guided in their upper portions in corresponding bores in the lower blocks 7a and 7b and have at their upper ends enlarged heads 10 located in corresponding bores 11 formed in the upper block 6 of the support'means. The bores 11 are blind bores extending from the bottom face of the block 7 into the latter and compression springs 12, located in these bores, aubt with the upper ends against the closed upper ends of the bores and with the lower ends against the top faces of the heads 10. The springs 12 thus constitute biasing means biasing the pressure pad portions 4a and 4b in a directionaway from the support means 3. A blade-like punch 5 extends in the rest position of the apparatus as illustrated in FIG. 1, with a lower portion thereof between inner side faces 40' and 4b of the two pressure pad portions 4a and 4b and is guided for movement in vertical direction between these side faces, whereas the upper portion of the punch is located in corresponding grooves formed in abutting side faces of the lower block portions 7a and 7b; The upper end face of the punch 5 abuts against the bottom face of a strip or key 13 locatedin longitudinally extending grooves of the aforementioned block portions 7a and 7b. The punch 5 is thus connected to the support means 3 for movement therewith, while the pressure pad portions 40 and 4b may move in vertical direction relative to the punch and the support means 3.

It is to be understood that the die 1 is to be placed on a stationary part of the punch press, or the like where as the upper block, 6 is to be connected to the ram of the punch press, which is notillustrated in the drawing, so as to move the pressure pad means 2 and the punch 5 in vertical direction toward and away from the die 1.

Each of the die blocks la and 1b is formed at the upper end thereof with a pair of longitudinal extending ridges l4 and 15 which form between themselves a longitudinally extending groove 16 having a bottom face 16 which is located at an elevation slightly higher than that of a bottom face 17' of a cut-out formed in each die block outside the ridge 14. The upper faces 14' and 15' of the ridges in both die blocks are located in a common plane and form together a locating face onto which the two tapes T and T of a continuous slide fastener chain, which has to be formed with a gap, is palced. The coils C and C respectively attached by thread means to the tapes adjacent the inner longitudinal edges thereof, are then located in cut-outs formed in the die blocks inwardly of the ridges 15, and while the inner surfaces of the two die blocks la and lb abut against each other, as shown in FIG. 1, each of the die blocks is formed at the inner face thereof with a groove so that the two grooves form togehter an axially extending slot 18, of a length substantially equal to the length of the gap to be produced, and defined by side faces 18a and 18b spaced apart from each other a distance greater then the width of the punch 5. The upper ends of the side faces 18a and 18b are outwardly inclined and terminate into cutting edges 19 extending longitudinally through the die. The cutting edges 19 are spaced from each other a distance greater than the spacing between the side faces 18a and 18b.

Each of the pressure pad portions 4a and db is provided with two longitudinally extending

ridges

20 and 21 which are respectively vertically aligned with the groove 16 and the outer cut-outs formed in the die blocks 1a and lb. The width of each ridge 20 is smaller than the width of the corresponding groove 16 by a dimension greater then twice the thickness of the respective tape, whereas the inner side face 211' of the ridge 21 in each pressure pad portion is transversely spaced from the corresponding outer side face 14a of the ridge 14 in the respective die block by a distance which is smaller than the thickness of the respective tape for a purpose, as will be described later on in detail. It will also be noted, that the downward extension of the outer ridges 21 is gerater than the downward extension of the inner ridges 20.

The operation of the above-described apparatus will now be further described on hand of FlGS. 2-6. In the open or rest position of the apparatus, as shown in FIG. 1, the two tapes T, and T are placed on the locating face of the die formed by the aligned upper faces 14' and 15 of the two ridges formed in each die block. When now the pressure pad means 2 are moved downwardly relative to the stationary die ll, to the position as shown in FIG. 2, the outer ridges 21 on the two pressure pad portions 4a and 4b will engage the two tapes in the region of the outer longitudinal edges thereof and bend the two tapes at the outer portions thereof about the ridges l4 of the two die blocks. Since, as mentioned above, the inner face 21' of the outer ridges 21 on the two pressure pad portions 4a and 4b are laterally spaced from the corresponding outer faces 14' of the outer ridges 14 in the two die blocks a distance smaller than the thickness of the tapes the outer portions of the tapes T and T will be clamped between the respective faces 21' and 14'. During further downward movement of the pressure pad 4, as shown in FIG. 3, the inner ridges 20 on the two pressure pad portions 4a and 4b will penetrate into the corresponding grooves 16 formed in the two die blocks 1a and lb so as to deflect a portion of each tape located between the outer clamped portions and the inner edges of the tapes in the manner as shown in FIG. 3 to thereby pull the inner edges of the tapes apart for an exactly controlled distance depending on the depth of the ridges 20. This pulling apart of the inner edges of the two tapes exposes part of the previously covered coils connected to the tapes without disengaging the interengaged coupling portions of the coils. Further downward movement of the pressure pad portions 44 and 4b is stopped when the same reach the position as illustrated in FIG. 3. When the pressure pad portions 4a and 4b are thus stopped, while the support means 3 shown in FIG. 1 move further downwardly, the punch advances downwardly relative to the now stationary held pressure pad portions 40 and 4b between the thus spread apart inner edges of the tapes into engagement with the coils C and C In the position of the punch 5 as shown in FIG. 4, the lower preferably rounded endface 5 of the punch engages the upper branches of the coils C and C to press the upper branches against the lower branches in the manner as shown in FIG. 4 and to press thereby the lower branches of the coils against the cutting edges l9 on the two die blocks la and 1b. In the position as shown in FIG. 4 cutting of the coils C and C will start. As mentioned before, the spacing between the two cutting edges 19 is greater than the spacing between the faces 18a and 18b and the spacing between the latter faces is made in such a manner that the punch 5 may penetrate with clearance into the slot defined by these two faces.

If the diameter of the plastic filaments from which the coils are formed is d, the distance a between the opposite faces 18a and 18b is preferably chosen in such a manner that when the punch penetrates into the slot 18 formed between the faces 18a and 18b, the clearance between each side face of the punch and the respective face 18a or 18b is smaller, preferably about one half of the diameter d of the coil filaments. The spacing b of the two cutting edges 19, on the other hand, is greater than the dimension a and preferably the distance b between the cutting edges 19 is about equal to the width of w of the punch 5 plus twice the diameter d.

The specific clearance between the side faces of the punch and the cutting edges 19 and the clearance between the side faces of the punch and the faces 18a and 18b which define the slot through the die will give the following results. When, in the position of the punch 5 as shown in FIG. 4, the rounded bottom face 5 of the punch presses the upper branches of the coils agains the lower branches and the latter against the cutting edges 19, the lower branches will be cut by the cutting edges during further downward movement of the punch. However, after the lower branches of the coils are cut, no cutting of the upper branches will occur during further downward movement of the punch since the clearance between the side faces of the punchand the respective cutting edge is about equal to the diameter of the coil filaments and therefore these filaments will not be cut but simply bent downwardly against the inclined side faces 19', and as the punch passes the junction between the inclined faces 19' and the corresponding vertical faces 18a or 19b, as shown in FIG. 5, the filaments of the cut coil convolutions C and C will be squeezed between the side faces of the punch and the respective side faces 18a and 18b to be taken along during further downward movement of the punch to be finally pulled out of the threads or stitches S as shown in FIG. 6.

Therefore, the above-mentioned relationship between the width of the punch, the diameter of the coil filaments, the spacing between the cutting edges 19 and the side faces 18a and 18b of the slot 18 through the die will assure that during downward movement of the punch into the slot only the lower branches of the coil filaments will be cut and the thus severed coil filaments will be pulled out in their entirety from the stitches which fasten the coils to the tape so that no remnants of the severed filaments will remain attached to the tapes.

The die 1, is, as mentioned before, made out of two parts which greatly facilitates grinding of the cutting edges 19 and the side faces 18a and 18b. The two die parts la and lb are connected to each other by

keys

23 and 24 as shown in FIG. 7. These keys extend transversely of the central slot 18 through the die and close the slot at opposite ends thereof. However, each of these keys is formed with a central vertically extending slot 23' and 24', respectively, which slots are aligned with the slot 18 but have each a width smaller than that of the slot 18. The width of the slots 23 and 24' is substantially equal to the width w of the punch 5 and while the punch has, as described above, over a major portion of its length a rounded bottom face 5', the punch has a pair of end portions 5" and 5", as shown in FIG. 8, which respectively will fit with a minimum clearance into the slots 23' and 24' and which have a bottom face normal to the side faces of the punch. These end portions of the punch 5 will cooperate with the slots 23 and 24' formed in the keys to properly cut end portions of the coils at the end of the gap formed in the continuous slide fastener chain so that such end portions will not protrude beyond the inner longitudinal edges of the tape.

FIG. 9 shows a modification of the apparatus as illustrated in FIG. 1. Th die 1 of the apparatus shown in FIG. 9 is very similar to the die as shown in FIG. 1 and the die 1 is also formed of two parts or die blocks la and lb and the only difference between these die blocks shown in FIG. 9 and those described above in connection with FIG. 1 is that the ridges 14" are wider then the ridges 14 shown in FIG. 1 and extend all the way toward the outer side faces of the two die blocks. The pressure pad 4' is likewise formed out of two parts, designated in FIG. 9 as 40 and 4d, which are guided on guide rods 9 for movement toward and away from the die 1. The support means 3 to which the upper ends of the guide rods 9 are connected are not shown in FIG. 9 and these support means are identical with those shown in FIG. 1. The two

pressure pad parts

40 and 4d are formed with downwardly extending ridges 20 which cooperate with the grooves 16 formed in the two die blocks in the same manner as described above in connection with FIG. 1. However, instead of the outer ridges 21 on the pressure pad parts as shown in FIG. 1 there are provided in the embodiment illustrated in FIG. 9 auxiliary pressure pads 26 which are movably guided in cutouts 28 formed in the pressure pad parts 4c and 4d. Coil compression springs 29 are located in the upper portions of the cut-outs 28 and engage with opposite ends the auxiliary pressure pads 26 and plates 30 connected by screws or the like to the upper ends of the blocks 4c and 4d closing the upper ends of the cut-outs 28. The springs may be centered by plugs 31 press-fitted in corresponding bores in the plates 30 and blind bores 32 at the upper ends of the auxiliary pressure pads 26. The cut-outs 28 have each an upper wider portion and a lower smaller portion and form shoulders 28 at the junction of these two portions and laterally extending ears 27 on the auxiliary pressure pads 26 prevent movement of the latter under the influence of the springs 29 in downward direction beyond the position shown in FIG. 9. The punch 5 is again guided between the inner side faces of the

pressure pad parts

40 and 4d.

The embodiment illustrated in FIG. 9 will operate as follows:

When the pressure pad 4' moves downwardly, in the manner as described above in connection with FIG. I, the bottom faces 26 of the auxiliary pressure pads 26 will engage the top faces of the tapes T and T in the region of the lateral outer edges of the latter and clamp the tapes in the region of the outer lateral edges thereof tightly against the top faces 14' of the ridges 14" of the two die blocks. Subsequently thereto, the ridges 20 of the pressure pad parts 4c and 4d will penetrate into the slots 16 formed in the two die blocks la and 1b to defleet the tapes between the inner and outer longitudinal edges thereof to thereby pull the inner edges apart in the manner as described above in connection with FIG. 1. Subsequently thereto, the punch blade 5 will penetrate between the pulled apart inner edges of the two tapes, sever the coils C and C and pull the same out of the stitches or threads which connect the coils to the two tapes, in the manner as described above.

While the construction shown in FIG. 9 is slightly more complicated than that shown in FIG. 1, this construction will assure a more exact pulling apart of the inner longitudinal edges of the two tapes than can be obtained with the construction as shown in FIG. 1 in which the two tapes may be slightly dragged along by the side faces 21' on the ridges 21. The construction shown in FIG. 9 which also prevent any damage of the tapes which may occur in the embodiment shown in FIG. I by squeezing the same tightly between the side faces 21' of the ridges 21 and the side faces 14a on the ridges 14. I

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of method and apparatus of producing gaps in slide fastener chains differing from the types described above.

While the invention has been illustrated and described as embodied in a method and apparatus of producing a gap in a covered slide fastener chain, it is not intended to be limited to the details'shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analyses, the foregoing will so fully reveal the gist of the present invention that others can be applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

I. A method of producing a gap in a slide fastener chain having tapes carrying along adjacent inner longitudinal edges continuous coils attached to the tape and having interengaged coupling portions, said coils being attached to said tapes so that the coils are covered at one side thereof by the tapes, said method comprising the steps of clamping the tapes in the region of outer longitudinal edges thereof at the desired location of a gap; deflecting the tapes between the thus clamped outer longitudinal edges and the interengaged coupling portions to thereby pull the inner longitudinal edges of the tapes apart in an exactly controlled manner and to expose the interengaged coupling parts; cutting the coils between the pulled apart inner longitudinal edges of said tapes for a distance corresponding to the desired length of the gap; and removing the cut coils from the tapes.

2. A method as defined in claim 1, wherein said coils are attached to said tapes by thread means, and wherein said step of removing the cut coils from said tapes comprises the step of pulling the cut coils out of the thread means.

3. A method as defined in claim 2, wherein the step of cutting said coils comprises the step of cutting said coils only at one side thereof.

4. A method as defined in claim 3, wherein said step of cutting said coils only at one side thereof comprises the steps of engaging said coils at said one side thereof by a pair of transversely spaced cutting edges of a die and at the other side thereof by an endface of a punch adapted to move with clearance between said cutting edges and moving said die and said punch relative to each other so that the punch passes between and beyond said cutting edges, and wherein said step of pulling the cut coils out of the thread means comprises the step of pinching the cut coils between side faces of the punch and opposite faces of said die spaced from each other a distance smaller than the spacing between said cutting edges during movement of said punch beyond said cutting edges.

5. In an apparatus for producing a gap in a slide fastener chain having tapes carrying along inner longitudinal edges continuous coils attached to the tapes and having interengaged coupling portions, in which said coils are attached to the tapes so that said coils are covered at one side thereof by said tapes, a combination comprising a die having a locating face on which a portion of said chain to be formed with said gap is adapted to rest; pressure pad means arranged opposite and movable toward and away from said locating face of said die, said die and said pressure pad means having first cooperating means to clamp said tapes of a chain resting on said locating face in the region of outer longitudinal edges, and second cooperating means to deflect a portion of each tape out of said locating face so as to pull the adjacent inner longitudinal edges of said tapes apart'and to thus expose the intercoupled portions of said coils; and a punch movable between the pulled apart inner longitudinal edges of said tapes and cooperating with the die for cutting the coils without cutting said tapes for a distance corresponding to a desired length of the gap.

6. A combination as defined in claim 5, wherein said first cooperating means comprises a pair of outer side faces of said die extending transverse to said locating face and a pair of cooperating faces on said pressure pad means extending respectively substantially parallel to said side faces spaced therefrom a distance to clamp the outer portions of the tapes between said side faces and said cooperating faces during movement of said pressure pad means toward said die.

7. A combination as defined in claim 5, wherein said first cooperating means comprise auxiliary pressure pad means carried by said first mentioned pressure pad means and having faces substantially parallel and facing outer portions of said locating face, and biasing means for yieldably biasing said auxiliary pressure pad means toward that locating face so that outer longitudinally extending portions of the tapes are clamped between said faces of said auxiliary pressure pad means and said portions of said locating face during movement of said pressure pad means towards said die.

8. A combination as defined in claim 5, wherein said second cooperating means for deflecting a portion of each tape out of said locating face comprise a pair of spaced longitudinally extending grooves in said die and corresponding longitudinally extending spaced ridges on said pressure pad means adapted to penetrate with clearance into said grooves, respectively, during movement of said pressure pad means towards said die.

9. A combination as defined in claim 5, and including means for removing said cut coils from said tapes.

10. A combination as defined in claim 5, wherein said coils are attached by thread means to said tapes and including means for pulling the cut coils out of the thread means.

1]. A combination as defined in claim 10, wherein said die has a central longitudinally extending slot having a length substantially equal to the gap to be produced and being defined by a pair of substantially parallel inner faces extending substantially normal to said locating face and spaced from each other so that said punch may move with clearance between said inner faces, and a pair of cutting edges to opposite sides of said slot, facing said pressure pad means and being spaced from each other a distance greater than said inner faces.

12. A combination as defined in claim 11, wherein said punch has, at least over a major portion of its length, a rounded bottom edge and a pair of side faces parallel with said inner faces defining said slot in said die, and wherein the clearance between said side faces of said punch and said cutting edges of the die is substantially twice the clearance between said side faces of said punch and said inner faces of the die which define said slot.

13. A combination as defined in claim 12, wherein said coils are formed from plastic filaments having a given diameter and wherein said inner faces defining said slot are spaced from each other a distance substantially equal to the diameter of said filaments so that, as said punch moves between said cutting edges of said die, said coils are cut only at the sides thereof engaging said cutting edges while during further movement of said punch into said slot the thus cut coils are squeezed between said side faces of said punch and said inner faces, dragged by said punch into said slot and pulled out of the thread means.

14. A combination as defined in claim 13, wherein said bottom edge of said punch has a pair of short end portions having planar faces substantially normal to said side faces and wherein said slot in said die has a pair of corresponding end portions having side faces spaced from each other a distance substantially equal to the width of said punch, said spaced cutting edges of said die end short of said end portions of said slot and said die has, in the region of said slot end portions, upper face portions substantially parallel to said locating face, whereby the ends of the coils located at opposite ends of the gap to be produced are cut so that such ends will not protrude in the gap.

15. A combination as defined in claim 14, wherein said die comprises two mirror symmetrical blocks connected to each other by a pair of key means respectively located in the region of the opposite ends of said slot, said slot end portions being arranged in said key means.

16. A combination as defined in claim 15, wherein said pressure pad means comprises support means movable towards and away from said die, a pair of mirror symmetrical adjacent pressure pad portions carried by said support means, guide means connected to said support means and said pressure pad portions for guiding the latter for movement relative to said support means towards and away from said die, and biasing means cooperating with said pressure pad portions for yieldably biasing the latter towards said die, said punch being fixed at the end thereof opposite said bottom edgeto said support means and passes with a portion thereof between said pressure pad portions to be guided by the latter.

17. A combination as defined in claim 16, wherein said support means comprises an upper block having a bottom face and being formed with a plurality of bores extending from said bottom face into said upper block, and a lower block fixed to said upper block and having a top face abutting against said bottom face, said lower block being formed with a plurality of bores respectively aligned with the bores in said upper block, said guide means comprising a plurality of rods slidingly guided in said bores in said lower block and being fixed at the lower ends thereof to said pressure pad portions and having at the upper end heads respectively located in said bores of said upper block, said biasing means comprising compression springs located in said bores of said upper block and engaging said heads of said rods.

Claims

1. A method of producing a gap in a slide fastener chain having tapes carrying along adjacent inner longitudinal edges continuous coils attached to the tape and having interengaged coupling portions, said coils being attached to said tapes so that the coils are covered at one side thereof by the tapes, said method comprising the steps of clamping the tapes in the region of outer longitudinal edges thereof at the desired location of a gap; deflecting the tapes between the thus clamped outer longitudinal edges and the interengaged coupling portions to thereby pull the inner longitudinal edges of the tapes apart in an exactly controlled manner and to expose the interengaged coupling parts; cutting the coils between the pulled apart inner longitudinal edges of said tapes for a distance corresponding to the desired length of the gap; and removing the cut coils from the tapes.

5. In an apparatus for producing a gap in a slide fastener chain having tapes carrying along inner longitudinal edges continuous coils attached to the tapes and having interengaged coupling portions, in which said coils are attached to the tapes so that said coils are covered at one side thereof by said tapes, a combination comprising a die having a locating face on which a portion of said chain to be formed with said gap is adapted to rest; pressure pad means arranged opposite and movable toward and away from said locating face of said die, said die and said pressure pad means having first cooperating means to clamp said tapes of a chain resting on said locating face in the region of outer longitudinal edges, and second cooperating means to deflect a portion of each tape out of said locating face so as to pull the adjacent inner longitudinal edges of said tapes apart and to Thus expose the intercoupled portions of said coils; and a punch movable between the pulled apart inner longitudinal edges of said tapes and cooperating with the die for cutting the coils without cutting said tapes for a distance corresponding to a desired length of the gap.

11. A combination as defined in claim 10, wherein said die has a central longitudinally extending slot having a length substantially equal to the gap to be produced and being defined by a pair of substantially parallel inner faces extending substantially normal to said locating face and spaced from each other so that said punch may move with clearance between said inner faces, and a pair of cutting edges to opposite sides of said slot, facing said pressure pad means and being spaced from each other a distance greater than said inner faces.

16. A combination as defined in claim 15, wherein said pressure pad means comprises support means movable towards and away from said die, a pair of mirror symmetrical adjacent pressure pad portions carried by said support means, guide means connected to said support means and said pressure pad portions for guiding the latter for movement relative to said support means towards and away from said die, and biasing means cooperating with said pressure pad portions for yieldably biasing the latter towards said die, said punch being fixed at the end thereof opposite said bottom edge to said support means and passes with a portion thereof between said pressure pad portions to be guided by the latter.