Note: Descriptions are shown in the official language in which they were submitted.
1089744
This invention relates to a slide fastener, and
more particularly to a fastener stringer having a con-
tinuous plastic filament spirally formed and woven into
an edge of a stringer tape during the weaving thereof.
There have been proposed a number of slide fasten-
ers or zippers of the type described, which comprise a
woven stringer tape and a plastic filament woven into a
longitudinal edge of the tape, the filament being usual-
ly formed into a helical coil structure consisting of a
row of successive elongated loops or convolutions each
having a coupling head, an upper and a lower leg and a
connecting portion.
Most of the known fasteners, however, have failed
to meet with the requirements for the success of the so-
called woven slide fasteners which largely depends on one
hand, upon the positional stability of the filament, i.e.
coupling fastener element, with respect to the stringer
tape against external stresses, and on the other hand,
upon smooth coupling and uncoupling of the opposed string-
ers by the action of a reciprocating slider.
When the filament is formed into a row of helicalllycoiled coupling loops and mounted on a stringer tape, such
loops would usually present a cross-sectionally oval shape
which is not complementary with the inner guide surfaces of
a slider and hence would often interfere with the sliding
movement of the latter during opening and closing of the
fastener stringers. With a view to eliminating this
difficulty, the coupling loops were covered by covering
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threads over their upper and lower surfaces including
their heel portions in such a manner that the covered
portions of the loops present a transverse cross section
complementary in shape with the guide channel of the
slider, as typically disclosed in Japanese Patent Publi-
cation Nos. 38-20175 and 47-15373. However, such prior
art devices have a common drawback in that due to the
covering threads being soft and bulky in nature, the
slider to be used for this type of stringer is required
to be built slightly smaller than the over-all dimentions
of the covered coupling loops taking into account the con- ~ .
traction of the covering threads which results from
engagement with the slider. This in turn creates an in-
crease in the resistance of thecovering threads to sliding
movement of theslider, resulting in disagreeable, some-
times interrupted coupling or uncoupling engagement of the
cooperating stringers.
According to the invention, there is provided a
woven fastener stringer comprising a woven tape formed
with foundation warp and weft threads and consisting of
a web section defining a major dimension of said tape and
a woven filament section defining a longitudinal edge por-
tion of said tape; a row of successively interconnected
elongated loops woven into said filament section and inter-
engageable with another row on a mating stringer by the
action of a slider, each of said loopshaving a coupling
head at one end thereof, an upper leg and a lower leg
extending from said head in a common direction, and a
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1089'744
heel portion remote from said head connected to a next
adjacent one of said successive loops; a binding system
securing said loops to said woven filament section and
comprising a plurality of theremoplastic yarns, one ex-
tending longitudinally of said tape in abutting engagement
with the upper surface of said heel portion and the other
extending longitudinally of said tape in abutting engage-
ment with the lower surface of said heel portion and a
binding weft thread continuing from said foundation weft
thread and interwoven with said thermoplastic binding
yarns, said thermoplastic binding yarns being elastically
deformed to assume an outer peripheral surface complementary
in shape with the inner guide walls of said slider and
integrally joining adjacent ones of said heel portions.
It is therefore a primary object of the present
invention to eliminate the foregoing difficulties encounter-
ed by the prior art devices.
A more specific object of the invention is to pro-
vide an improved fastener stringer which has a row of
successive coupling loops firmly secured and properly
aligned in place on a stringer tape.
Another related object of the invention is to provide
an improved fastener stringer covering a row of coupling
loops interengageable smoothly and effectively with another
row of loops on a mating stringer in response to recipro-
cating movement of a slider.
These and other objects and features will be better
understood from the following detailed description of a
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preferred embodiment taken in conjunction with the accom-
panying drawings.
In the drawings wherein like refernece numerals
refer to like parts:
Fig. 1 is a plan view on enlarged scale of a portion
of one of two identical stringers according to one embodi-
ment of the invention;
Fig. 2 is a transverse cross-sectional view taken
on the line II - II of Fig. 1 with a slider mounted on the
stringer;
Fig. 3 is a transverse cross-sectional view of a
stringer which appears prior to finishing according to the
invention;
Fig. 4 is a transverse cross-sectional view of a
stringer according to another embodiment of the invention;
and
Fig. 5 is a diagrammatic view illustrating the
operation of a slide fastener.
Referring now to Figs. 1 - 3, which illustrate a
first preferred embodiment of the invention, there is shown
a fastener stringer generally designated 10 which consti-
tutes one part of a pair cr two identical stringers for a
slide fastener. The stringer 10 consists of a generally
flat web section _ defining a major dimension of a woven
tape 11 and a woven filament section Wf defining a longi-
tudinal edge portion 12 into which a filament 13 of plastic
material is woven. The filament 13 is formed from a linear
blank of a suitable plastic material into a helically coil-
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1089744
ed structure having a succession of loops or elongated ;
convolutions during the course of weaving of the tape 11.
Each loop or elongated convolution 14 in the fila-
ment 13 has a coupling head 14a at one end thereof, an
upper leg 14_ and a lower leg 14c extending from the head
14a in a common direction and a heel portion 14d remote
from the head 14a connected to a next adjacent one of the
successive loops 14. The coupling head 14a is dimensioned
to releasably couple with a corresponding head of a loop
14 on a mating stringer to open and close the fastener in
the well known manner. The upper and lower legs 14_ and
14c are spaced apart in substantially superimposed relation
to each other as shown in Fig. 1 and define therebetween
a longitudinally extending "tunnel" or hollow conduit
through which a reinforcing string, cord or core 15 is
inserted.
The web section W of the tape 11 may be of any known
design having foundation warp threads 16 and foundation
weft thread 17 interwoven in a variety of patterns such as
a combination of plain weave 18 and twill weave 19, as
shown, which will require no further explanation as this
has no direct bearing upon the invention.
The term "filament woven section W~" is used to
define a longitudinal edge portion of the tape 11 into
which the filament 13 serving as a coupling element for
a slide fastener is woven. The row of coupling loops 14
is secured to the filament woven section Wf by a binding
system 20 which comprises a first group of binding warp
108~'749~ ~
threads 21, a second group of binding warp threads 22, a ~:
plurality of relatively large diameter thermoplastic bind~
ing yarns 23,24 and a binding weft thread 25 which is a
continuous portion of the foundation weft thread 17.
The first group of binding warp threads 21 extend
longitudinally of the stringer tape 11 and overlie the
upper legs 14b of successive loops 14 adjacent to the heel
portions 14_. The second group of binding warp threads 22
extend longitudinally of the stringer tape 11 and underlie
the lower legs 14c of successive loops 14 adjacent to the :
heel portions 14d. One of the thermoplastic binding yarns
23,(24) extends longitudinally of the stringer tape 11 in
abutting engagement with the upper surface 14_' of the heel
portion 14d of each loop 14, and the other binding yarn 24
extends longitudinally of the stringer tape 11 in abutting
engagement with the lower surface 14d" of the heel portion
14d. The binding weft thread 25 is passed around and in
interlaced relation to the first and second groups of bind-
ing warp threads 21,22 and the thermoplastic binding
yarns 23,24 and bind all of these warp materials together
into an integral binding system securing the row of coupl-
ing loops 14 via cord 15 to the woven filament section Wf
of the tape 11.
The thermoplastic binding yarns 23,24 are compressed
where these are interlaced or interwoven with the weft thread
25, with resultant swollen portions 26 alternating at
intervals with compressed portion 27 along the length of
the yarns 23,(24), as better shown in Fig. 3 in which the
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yarns 23,24 at the left-hand side represent the respective
swollen portions 26 and those at the right-hand side re-
present the respective compressed portions 27.
In accordance with the invention, the thermoplastic
binding yarns 23,24 are subjected to thermal compression -
molding with use of a suitable die having such a working
surface that the mass of the yarns 23,24 is elastically
deformed to assume an outer peripheral surface complimentary
in shape with the inner peripheral guide walls S' of a
slider S as shown in Fig. 2. Elastically deformed mass
23',(24') penetrates into the spaces defined by the heel
portons 14d between each adjacent pair of loops 14 and
joins adjacent heel portions 14_ together, so that the
heel portions 14_, which would otherwise be movable rela-
tive to adjacent ones of successively interconnected loops
14 in a row, are held integrally together. This ensures
not only firm fixation of the row of loops 14 to the tape
11, but also smooth, effective coupling and uncoupling
operation of the two opposed stringers 10 as the neutral
zone of each loop 14 which is free of both compressive
and tensile stresses is maintained in close proximity to
the heel portion 14d remote from the coupling head 14a
so as to create an increased free area in each loop
available for coupling engagement with adjacent loops.
Fig. 5 is utilized to explain the behaviour of the
respective rows of coupling loops 14, in which a solid
line N represents the position of the neutral zone of each
of successive loops 14 which lies close to the heel por-
1089~44 :: -
tion 14d according to the invention, and a chain-dotted
line M represents the position of the neutral zone of the
prior art loops which is shifted closely toward the coupl-
ing head 14a.
Fig. 4 shows a second embodiment of this invention
which is substantailly the same as the first embodiment
already described, except for theomission of binding warp
threads 21,22 and cord 15. This modification provides
basically the same function and results in so far as the
heel portions 14_ between each adjacent pair of loops 14
are integrally joined together by elastically deformed
mass of the thermoplastic binding yarns 23,24.
Although various minor modifications may be suggest-
ed by those veresed in the art, it should be understood
that we wish to embody within the scope of the patent
warranted hereon, all such embodiments as reasonably and
properly come within the scope of our contribution to the
art.
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