Separable Zip Fastener

Abstract

A zip fastener of the separable type wherein two rows of connecting members comprise at one of their ends a separable junction device consisting of two members, that is, a male member and a substantially box-shaped female member, formed by molding plastic material directly on the ends of said two ends. Before molding said members there is cut in each carrier tape of the zip fastener a notch which extends from the inner edge of said tape to at least the middle line thereof, whereafter during the making of the members of said junction device, there is formed in each plate solid therewith on the one hand a flat face of relatively great thickness which is adjacent to the corresponding junction member, and on the other hand, on the opposite side, area having a series of transverse grooves formed therein which extends over said tape proper.

Description

The present invention relates to zip fasteners of the so-called separable type.

The two component sections of zip fasteners of this type comprise a separable junction device at their ends where the control slide is positioned at the end of its opening stroke. This device comprises on the one hand a box-shaped female member fitted to the corresponding end of one of the two rows of connecting members, which acts as a stop member to the slide, and on the other hand a male member adapted to be engaged into said box-shaped female member and provided at the corresponding end of the other row of connecting members.

More particularly, this invention is concerned with zip fasteners of this character wherein the two members constituting said junction device are obtained by molding from plastic material, i.e., by embedding therein the corresponding ends of the two rows of connecting members and also the relevant portions of the tapes supporting these rows. In fact, these junction members are characterized by obvious advantageous features in comparison with similar members which up to now consisted chiefly of metal staples secured by crimping to the ends of the tapes supporting the connecting members.

In order to ensure a reliable and satisfactory fastening of the molded junction members of plastic material, each one of these members is formed integrally, as a rule, with a plate inserted to the end of the relevant tape. Of course, this plate is formed by molding plastic material directly on the tape and integrally with the corresponding junction member. Under these conditions the function of this plate consists not only in improving the fastening of this junction member but also in stiffening the tape end and prevent this end from teasing out.

However, to permit the sewing of the ends of a separable zip fastener to a garment or any other desired article there are provided as a rule one or more grooves extending transversely in small plates formed integrally with said junction members. Under these conditions each end piece consisting of a male or female junction member and the associated small plate is characterized by a sudden variation in its flexibility along the longitudinal line corresponding to the ends of said transverse grooves. In fact, the plate formed with these grooves obviously has a greater flexibility than the junction member proper which is substantially rigid. Thus, when zip fasteners of this type are used the end members are frequently torn or broken along the above-defined line separating the two zones of different flexibility of the end pieces. On the other hand the end members thus formed have a poor resistance to stress exerted in the transverse direction.

It is therefore a first object of this invention to eliminate these various inconveniences by avoiding a too sudden variation in the flexibility of the various zones of the end members provided in separable zip fasteners.

To this end, this invention provides primarily a method of manufacturing zip fasteners of the type set forth which is characterized in that before moulding the above-defined members a notch is cut in each tape supporting the fastener, this notch extending from the inner edge of the tape to at least the middle line thereof, and preferably beyond this line. Then, when making the component elements of the junction device, each plate rigid therewith has formed therein on the one hand a flat face of relatively great thickness which is adjacent to the corresponding junction member, and on the other hand, on the opposite side, a zone formed with a series of transverse grooves which extends both over the location of the notch formed in the tape and over the latter. Finally, the ends of these grooves are connected to the corresponding flat face through inclined portions having an obtuse angle of inclination.

With these various provisions and due more particularly to the angle of inclination of the ends of the transverse grooves, the end members thus formed are free of any sudden variation in their flexibility along a same line. In fact, they comprise two well-defined portions having different flexibilities, and also intermediate zones therebetween.

Of course, it is another object of this invention to provide a zip fastener of the separable type, obtained by carrying out the method set forth hereinabove.

However, other features and advantages of this method and of the zip fasteners obtained therewith will appear as the following description proceeds with reference to the accompanying drawings given by way of example. In the drawings:

FIG. 1 is a plane view from above showing the ends of the pair of tapes supporting a fastener, after cutting the notches therein;

FIG. 2 is a plane view from above showing the same ends after the molding of the plastic junction inserts thereon;

FIGS. 3 and 4 are cross-sectional views taken along the lines III--III and IV--IV of FIG. 2, respectively;

FIG. 5 is a fragmentary longitudinal section taken along the line V--V of FIG. 2;

FIG. 6 is a plane view from above of one of the junction members shown in FIG. 2, in this case the female member;

FIG. 7 is a fragmentary section taken on a different scale along the line III--III of FIG. 2.

According to the manufacturing method of this invention the first step thereof consists in cutting two notches 2a and 2b in the tapes 1a and 1b supporting the two rows of connecting members 3a and 3b of the zip fastener being manufactured. Of course, these notches are made at the ends of the tapes where the separable junction members 4a and 4b are to be fitted, the female member 4b being substantially box-shaped and adapted to receive the male member 4a.

The shape and dimensions of these two notches are such that each of them covers not only the area to be occupied by the corresponding junction member but also one fraction of the area to be occupied by the plate to be associated with said member. To this end, each notch 2a or 2b extends from the inner edge of the corresponding carrier tape 1a or 1b to the middle line A-B or C-D of the relevant tape, and preferably beyond this line.

The shape of these two notches may vary, of course, provided that the above-defined requirement is duly met.

After cutting the notches 2a and 2b the two junction members contemplated are formed by molding plastic material directly on the proper face of each carrier tape 1a and 1b. Each junction member will thus be located at the end of the corresponding row of connecting members, 3a and 3b respectively; however, the box-shaped female member 4b is connected to these molded members by another element 4c also of molded plastic material, which has roughly the shape of a small longitudinal bar. Each junction member is associated with a plastic plate formed by molding over the end of the relevant tape 1a or 1b.

Each plate comprises on the one hand a relatively thick flat face 6a or 6b adjacent to the corresponding junction member 4a or 4b, and on the other hand a zone denoted by the general reference symbol 5a or 5b which comprises a series of grooves 7a and 7b extending in the transverse direction.

In this respect, it may be noted that one portion of the two zones 5a and 5b extends over the corresponding carrier tape 1a or 1b, another portion of each one of said zones registering with the notch 2a or 2b cut beforehand in the tape. Of course, the thickness corresponding to the tape material thus removed is filled with plastic material during the molding operation in order to provide a surface underneath which is flush with the remaining rear surface of the tape.

The depth of grooves 7a and 7b is such that the corresponding tape 1a or 1b is uncovered in the zone thereof underlying the plate 5a or 5b. The grooves thus provided form between them plastic ribs 8a or 8b of which the upper surface is flush with the corresponding surface of the adjacent face 6a or 6b. On the other hand, on their outer sides the ends of these grooves are interconnected by a rib 9a or 9b also flush with the upper surface of faces 6a or 6b.

Finally, the grooves 7a and 7b are connected to the adjacent faces 6a or 6b through inclined portion of which the angle of inclination .alpha. exceeds 90.degree. (see FIG. 3). Besides, this angle is preferably very obtuse; thus, an angle of about 135.degree. may be used.

This very particular shape is advantageous in that it avoids any risk of bending at the ends of the transverse grooves 7a or 7b.

Besides, the other features of this invention also assist in eliminating any risk of accidental and accentuate bending or breaking resulting from a sudden variation in the transverse flexibility of the end members.

In fact, as seen in the transverse direction there are several portions having different flexibility values, and also intermediate zones therebetween. Thus, portions 5a or 5b comprising transverse grooves are not connected directly with the junction members 4a or 4b, but a flat face 6a or 6b having a certain thickness is provided therebetween, in order to constitute an intermediate zone between these two portions of which one is substantially rigid and the other is flexible.

On the other hand, the portions 5a and 5b comprising said transverse grooves extend both over the carrier tapes and over the areas thereof which have been removed as a consequence of the cutting of notches 2a and 2b therein.

Due to these various features and more particularly to the inclination of the end portions of grooves 7a and 7b at an obtuse angle, any risk of tearing the end members is definitely precluded.

On the other hand, the parts thus obtained have a good resistance to traction stresses exerted in the transverse direction.

Preferably, the notches 2a and 2b cut initially in the end portions of the carrier tapes 1a and 1b are also so designed that in the longitudinal direction the various portions of each end member extend both over the corresponding carrier tape 1a or 1b and over the zone thereof which has been removed completely as a consequence of the cutting of said notches. To this end, these notches extend from the end edges of the two tapes to a transverse line I-F (FIG. 2).

Also preferably, transverse ribs are provided, as shown at 10a and 10b respectively, on the opposite face of the supporting tapes 1a and 1b (see FIGS. 4 and 6). These ribs are also formed by molding plastic bodily with the plates 5a and 5b and junction members 4a and 4b.

Due to the presence of said ribs 10a and 10b on the opposite face of the tapes the fastening of the junction members to these tapes is improved to a substantial degree. The ends of these ribs may advantageously be connected to the junction members through an angle .beta. greater than 90.degree.. Besides, this angle may also have the same value as the above-defined angle of inclination .alpha. of the corresponding ends of grooves 7a and 7b formed on the opposite face. The ribs 10a and 10b may have a length equal to or other than that of grooves 7a and 7b. On the other hand, these ribs may either register with those 8a and 8b formed between these grooves or be coincident with these grooves.

However, it is clear that the junction members provided at the ends of the zip fasteners obtained by using the method of this invention should not be construed as being strictly limited by the specific and single example described hereinabove by way of illustration. Anybody skilled in the art will readily understand that various modifications may be brought thereto without departing from the spirit and scope of the invention.

As already mentioned hereinabove, the manufacturing method according to this invention may be used for making zip fasteners of the so-called separable type, that is, fasteners wherein the two component sections can be separated completely from each other. Of course, the connecting members provided on these two sections may be of any desired type. In fact, in the example illustrated, connecting members are shown which consist of a continuous wire wound to a variable pitch helix. However, this only an example for these connecting members may consist as well of other known means such as separate metal staples or the like.

Claims

What I claim is:

1. Zip fastener of the separable type comprising two rows of connecting members which comprise at one end a separable junction device consisting of two members, that is, a male member and a substantially box-shaped female member, respectively, of molded plastic material directly over the ends of said two rows, each member of said junction device being rigid with a molded plastic plate fixed on the end of the corresponding carrier tape, each carrier tape of said zip fastener comprising a notched portion extending from the inner edge of said tape to at least the middle line thereof, each plate rigid with a junction member comprising on the one hand a flat face of relatively great thickness which is adjacent the corresponding junction member, and on the other hand on the opposite side, a zone formed with a series of transverse grooves, said last named zone extending both over one portion of the notch formed in said tape and over one portion of said tape, an inclined surface having an obtuse angle of inclination being provided on the other hand for connecting the ends of said grooves to the corresponding flat face.