Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF T'IE INVENTION
Field of the Inven-tion:
The present invention relates to slide fasteners,
and more particularly to a watertight slide fastener
stringer.
Prior Art:
Watertight slide fastener stringers are known which
generally comprise a single support tape made of a water-
tight soft material, and a row of discrete coupling
elements mounted on the tape along an inner longitudinal
edge portion thereof; such tape margin is folded so as to
provide therealong a contact portion engageable with a
corresponding contact portion of a like companion stringer
to effect a watertightness between the two stringers. When
the opposed coupling element rows of the two stringers are
interengaged by a slider to close the watertight slide
fastener, the opposed contact portions are brought into
contact with one another. The common problem with this
type of watertight stringer is that the interengaged
individual coupling elements are subjected to rolling or
tilting due to undue stress induced by lateral pulling
forces exerted on the tapes and by thrusting forces exerted
on the coupling element rows. This rolling of the coupling
elements impairs the contact between the opposed contact
portions, thus causing insufficient watertightness between
the opposed stringers. Japanese Utility Model Publication
(Jikkosho) 53-4~161, issued October 12, 1978, is believed
to exemplify the prior art.
S~MMARY OF THE INVENTION
It is therefore an object of the invention to
provide a watertight slide fastener stringer which enables
efficient and reliable watertightness between the opposed
companion stringers.
Another object of the invention is to provide a
watertight slide fastener stringer which enables smooth
movement of a slidex~
According to the present invention, a watertight
slide fastener stringer comprises a row of discrete
coupling elements mounted on a support tape and an
auxiliary tape along their folded edge portions, there
being first and second contact portions contiguous to the
respective folded edge portions and engageable with`
corresponding rirst and second contact portions, respec-
tively, of a like companion stringer to effect water-
tightness not only between the two support tapes but also
between the two auxiliary tapes. Each coupling element has
a neck extending centrally from a base, and a pair of legs
extending from opposite ends of the base in the same
direction as the neck so as to hold the folded edge
portions of the support and auxiliary tapes between one leg
and the neck and between the latter and the other leg,
respectively. Each leg terminates in a flange disposed on
the contact portion. With the watertight slide fastener in
closed position, if lateral pulling forces, for example,
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are exerted on the opposed tapes, the opposed coupling
elements roll or tilt so as to reduce the tightness between
the opposed first contact portions. At the same time this
rolling causes the opposed second contact portions to be
pressed against each other with increased tightness, thus
guaranteeing efficient and reliable watertightness between
the opposed companion stringers.
Many other advantages, features and additional
objects of the present invention will become manifest to
those versed in the art upon making reference to the
detailed description and the accompanying drawings in which
a preferred embodiment incorporating the principles of the
present invention is shown by way of illustrative example.
B~IEF DESCE~IPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a coupling element
for a watertight slide fastener stringer embodying t'ne
present invention;
FIG. 2 is a fragmentary plan view, partly in longi-
tudinal cross section, of the watertight slide fastener
stringer;
FIG. 3 is a fragmentary transverse cross sectional
view of the stringer;
E`IG. 4 is a fragmentary plan view, partly in
longitudinal cross section, of the stringer of FIGS. 2 and
3, showing the same having been interengaged with a like
companion stringer; and
FIG. 5 is a fragmentary transverse cross-sectional
view of the opposed companion stringers of FIG. ~.
DETAILED DESCRIPTION
The principles of the present invention are
particularly useful when embodied in a watertight slide
fastener stringer (hereinafter referred to as "stringer")
such as shown in FIGS. 2 and 3, generally indicated by the
numeral 20.
The stringer 20 includes a support tape 7 made of a
watertight soft ma-terial such as natural or synthetic
rubber, or made of natural or synthetic fibers coated with
such a watertight material. The tape 7 has an inner
longitudinal margin folded through its whole length so as
to provide a first folded edge portion 7a and a first
contact portion 7b contiguous thereto. An auxiliary tape
8, which is made of the same watertight material as the
support tape 7 and coextends lengthwise therewith, has a
second folded edge portion 8a and a second contact portion
8b. The first and second folded edge portions 7a, ~a are
spaced apart facewise from one another~ while the first and
second contact portions 7b, 8b are laterally (vertically in
FIG. 3) spaced apart from one another. Alternatively, the
auxiliary tape 8 may be an integral part of the support
tape 7. The first and second contact por-tions 7a, 8a are
adapted to engage corresponding first and second contact
portions 7'a, 8'a, respectively, of a like companion
stringer 20' (FIGS. 4 and 5), to effect a watertightness
between the two s-tringers 20, 20'.
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A first core thread 9 coextends lengthwise with the
support tape 7 and is attached to the first folded edge
portion 7a. Likewise, a second core thread 10 coextends
lengthwise with the auxiliary tape 8 and is attached to the
second folded edge portion 8a.
A row of discrete coupling elements 1 is mounted on
and along the first and second folded edge portions 7a, 8a
of the tapes 7, 8; each coupling element 1 has a base 2, a
neck 6, a coupling head 5, and first and second legs 3a,
3b. The base 2 is disposed remotely from and parallel to
the first and second contact portion 7b, 8b. The neck 6
extends centrally from the base 2 and is disposed between
the first and second folded edge portions 7a, 8a. The
coupling head 5, in the form of an enlarged portion,
extends from the neck 6 beyond the first and second contact
portions 7b, 8b. The first and second legs 3a, 3b extend
from opposite ends of the base 2 in the same direction as
the neck 6 so as to hold tightly the first and second
folded edge portions 7a, 8a between the first leg 3a and
the neck 6 and between the latter and the second leg 3b,
respectively.
The first and second legs 3a, 3b terminate in first
and second flanges 4a, 4b, respectively, disposed on the
respective back surfaces of the first and second contact
portions 7b~ 8b. Each of the first and second flanges 4a,
4b has inner and outer sections projecting in opposite
directions from a respective one of the first and second
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legs 3a, 3b. The first and second core threads 9, 10 are
disposed between the inner section of the first flange 4a
and the base 2 and between the inner section of the second
flange 4b and the base 2, respectively. The inner flange
sections serve to assist in holding the folded edge
portions and the core threads in place between the neck 6
and the legs 3a, 3b. The outer flange sections serve as
guide rails for a slider 11 tFIG. 5).
The slider 11 has in its inner wall 12 a longi-
tudinal groove 13 for the passage therethrough of the outer
sections of the second flanges 4b, 4'b and the outer halves
of the second con-tact portions 8b, 8'b.
When the opposed rows of coupling elements 1, 1' of
the two companion stringers 20, 20' tFIGS. 4 and ~) are
interengaged by the slider 11 to close the watertight slide
fastener, the opposed first contact portions 7b, 7'b are
pressed against one another to effect a watertight between
the opposed support tapes 7, 7' and, likewise the opposed
second contact portions 8b, 8'b are pressed against one
another to effect a watertightness between the opposed
auxiliary tapes 8, 8l. During this interengagement, the
slider 11 slides on outer surfaces 4c, 4'c of the first
flanges 4a, 4'a and also on outer surfaces 4d, 4'd of the
second flanges 4b, 4'b.
With the watertight slide fastener thus in closed
position, when lateral pulling forces are exerted on the
opposed support -tapes 7, 7', or when a thrusting force is
exerted on the interengaged coupling element rows 1, 1',
~he opposed individual coupling elements 1, 1' roll or tilt
so as to allow reduced tightness between the opposed first
contact portions 7b, 7'b. At the same time this rolling of
the coupling elements 1, 1' causes the opposed second
contact portions 8b, 8'b to be pressed against one other
with increased tightness thus maintaining efficient and
reliable watertightness between the opposed companion
stringers 20, 20'.
With the watertight slide fastener stringer 20,
since the support tape 7 and the auxiliary tape 8 are
folded to virtually embrace the first and second flanges
4a, 4b, respectively, an improved watertightness can be
achieved.
Ano-ther advantage of the watertight stringer 20 is
that during interengagement of the opposed companion
stringers 20, 20', the slider 11 is guided by the firs-t
flanges 4a, 4'a and also by the second flanges 4b, 4'b,
thus guaranteeing smooth movement of the slider. Further,
since the slider 11 does not touch either the support tape
7 or the auxiliary tape 8 during movement along the opposed
coupling element rows 1, 1', these tapes 7, 8 are Eree from
being easily worn or otherwise damaged, thus guaranteeing
reliable slide fastener functions and efficient water-
tightness for a long period of time.
Although various minor modifications may be
suggested by those versed in the art, it should be
understood that I wish to embody within the scope of the
patent ~ranted hereon, all such embodiments as reasonably
and properly come within the scope of my contribution to
the art.
