AU477018B2 - Sliding clasp fasteners - Google Patents

Description

This invention relas 50 152 /72 to sliding clasp fasteners and more particularly to a method of

anufactu.rin a stringer for a fastener.

A sliding clasp fastener comprises two

stringers each having a row of coupling elements secured

to a carrier tape, and a slider mounted on the rows of elements to effect interengagement and disengagement

of the elements as the slider is noved along the

stringers..

It is now -ell known to manufacture each

stringer of a fastener by forming a row of coupling

elements from a length of plastics filament and to

secure the elements to an edge portion of a tape by

stitching. How.ever, when such a fastener is assembled and under lateral loads, as occurs for instance in a fastener fitted in the side opening of a skirt, there

is a tendency for relative movement to take place

between the stitches and the elements. This is particularly disadvantageous in the case of so-called

concealed-type fasteners wherein the tape of each

stringer has a fold extending longitudinally of the

tape and coupling elements are secured to the tape

on one side of the fold with the fold located adjacent

coupling head portions of the elements. When the fastener is closed with the two rows of elements interengaged, the tape folds lie adjacent to one another

so as substantially completely to conceal the elements

when viewed from one side of the fastener. In such concealed-type fasteners lateral loads which are

sufficient to move the stitches along the elements 2 477.018 lead to parting of the 50 152/72 tapes of the two stringers from one another and consequent showing of the elements at the normally concealed side.

It has been proposed to obviate the

above mentioned relative movement of the stitches

and elements by providing grooves or recesses in the

outer surfaces of the elements to provide a location

for the stitches but in practice it is difficult to

control to consistent accuracy the position and depth

of the grooves or recesses.

According to/the present invention a method

of manufacturing a stringer for a sliding clasp fastener,

comprises forming a row of coupling elements from a

length of plastics filament, securing the row of elements

along an edge of a tape by means of stitches, there-

after heating the surfaces of the coupling elements

in direct contact with the stitches sufficiently to

soften said surfaces, and then applying pressure to the

stitches to press the stitches at least partly into the

softened surfaces of the elements, and maintaining the

stitches in this position during hardening of the

plastics material thereby to minimise relative movement

of the stitches along the elements.

47 7 0 1 8

50.152/72

In order that the invention may be more clearly

understood, one embodiment thereof will now be described

by way of example only with reference to the accompanying

drawings, in which:

Figure 1 is a lateral cross-sectional view of a

stringer for a concealed type fastener at one stage of

manufacture;

477 0 18

50. 15 2. 72 Figure 2 is a view similar to Yi.ure 1 at

a further stage of manufactur-e,- and

Fi_-ure 3 is a lateral cross-sectional view

of the finished stringer.

Referring to Figure 1 of the dra.wings, a

stringer 1 for a sliding clasp fastener is manufactured

in kno-:n manner by taking a length of plastics

filament of circular cross-section, forming flattened

and widened portions at regular intervals along the

length, and winding the filament into a coil around

a textile cord 2 so that the widened portions are

longitudinally aligned along the coil to provide coupling

heads 3, the coil thus constituting a row: of coupling

elements L4. The row of elements is secured along an

edge of a flat carrier tape 5 by two rows of stitches

6. It will be seen from Figure 1 that the

elemenzs are located for sewing with their coupling

heads facing across the tape.

The stringer thus made is then passed

through a radiant heating means (not shown) which

directs radiant heat to the surfaces of the elements

indicated at 7. These surfaces 7 which are remote

from the tape 5 are in direct contact with the stitches

6. Heating is effected at a temperature and for a time

sufficient to soften the surfaces 7. 'hrilst these

surfaces are still in a softened condition, the stringer

is moved bet-.-een pressure applying means, conveniently

a pair of rolls, to apply pressure to the tape

and to parts of the stitches 6 which overlie the surfaces

7 so as to press said parts of the stitches into the- q 47 7.0 18

S50,152/72 softened material of the surfaces 7 as shown in Figure 2.

Follo:;ing resolidification of the surfaces 7 by

cooling, the tape 5 is reversely folded as shown

in Figure 3 and the fold is set by steam ironing, the

coupling heads now facing away from the tape5, to

constitute a stringer for a concealed-type fastener.

By virtue of parts of the stitches 6 being

embedded in the surfaces 7 of the coupling elements,

the stitches cannot slide along these surfaces when opposing lateral loads are applied to the elements and

the tape.

The above embodiment has been described in

relation to coil-type stringer but is equally applicable

to other types of stringer, for example, stringer known

in the art as meander type. Furthermore, under suitable

conditions of heat and pressure, the stitches may be

completely embedded at the side of the elements remote

from the tape.

477 0 1

Claims (4)

50,152/72 The claims defining the invention are as follows:-

1. A method of manufacturing a strincr for a

sliding clasp fastener, comprising forming a row of

coupling elements from a length of plastics filament,

securing the row of elements along an edge of a tape

by means of stitches, thereafter heating the surfaces

of the coupling elements in direct contact with the

stitches sufficiently to soften said surfaces, and

then applying pressure to the stitches to press the

stitches at least partly into the softened surfaces

of the elements, and maintaining the stitches in this

position during hardening of the plastics material

thereby to minimise relative movement of the stitches

along the elements.

2. A method according to claim 1 wherein the row

of coupling elements is secured along an edge of a flat

tape with coupling heads of the elements facing across

the tape, and after the application of heat and pressure

the tape is reversely folded so that the coupling heads

face away from the tape.

3. A method of manufacturing a stringer for a

sliding clasp fastener, substantially as described

herein, with reference to Figures 1 to 3 of the

accompanying drawings.

4. co a 50,152/72 sliding clza.sp fastener, 7dflufactur-yd by tile i:-iethod of either of claims I or 2.

rIn-er, for a slidijng clasp fastener, su" l:latially as described herein and with reference to -,ure3o the acco-,:; anying drawings

D. TED: 7 1976

.'Orny, for:-- V.MTZ

47 7 0 18

.50.152./72

FIG. I.

/6

FIG. 2.

Z-

FIG. 3.

47 7 0 18