Note: Descriptions are shown in the official language in which they were submitted.
BA~KGROUND OF THE INVENTION 1 3 1 2 4 5 1
1. Field of the Invention:
~ This invention relates generally to slide fasteners
and more particularly to a slider therefor.
2. Prior Art:
Prior Art relevant to the present invention will now be
described with reference to one of the accompanying drawings,
wherein:
FIG. 1 is a fragmentary side elevational view on
enlarged scale of a double pull tab slider embodying the
invention;
FIG. 2 is an enlarged sectional view taken on the line
II - II of FIG. 1 with fastener tapes removed and showing
one mode of locking action;
FIG. 3 is an enlarged sectional view taken on the line
III- III of FIG. 1 with fastener tapes removed;
FIG. 4 is a view similar to FIG. 2 but is utilized to
explain another mode of locking action;
FIGS. 5a and 5b each are a diagrammatic view showing
alternative positions of locking means according to the
invention; and
FIG. 6 is a fragmentary sectional view similar to FIG.
2 but of a prior art slider.
Numerous types of sliders for opening and closing the
slide fasteners have been proposed which are provided with
means for locking the slider in position against
unintentional movement subject to a force tending to spread
or open the fastener. One such locking means was formed on
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a pull tab attached to and adapted to facilitate movement of
the slider body. For slide fasteners, however, having
ladder-type or meandering coupling elements in two rows, one
on the upper and the other on the lower side of the
fastener, the locking means was preferably provided on or in
connection with the flangè portion of the slider body. A
slider with the latter type of locking means was disclosed
in U.S. Patent No. 3,798,714 in which the slider (as shown
in FIG. 6) has a pair of locking tabs or projections 100 and
101, one of upper opposed flanges 102 on an upper wing
member and the other tab or projection on a corresponding
extreme end of one of lower opposed flanges 103 on a lower
wing member, the locking tabs 100 and 102 engageable with
the heel portions 104 of the coupling elements E
respectively on the upper and lower sides of the fastener to
prevent spontaneous spreading-apart action of the
confronting stringers. Whilst this prior flange-lock slider
has its own advantages, it has a drawback in that either one
of the pair of locking tabs would fail to lockably engage
with the heel portion of the coupling element in the event
that the opposed stringers are coupled together with the
coupling elements in one row misaligned with respect to
those in the other row; that is when the elements on one
stringer are interengaged with their counterparts on the
other stringer with one element pitch shifted out of
position either in the opening or the closing direction of
the fastener, or stated otherwise when the coupling elements
on the right side are disposed half an element pitch out of
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alignment with respect to those on the left side as
visualized in FIG. 6, in which instance only one of the two
locking tabs engages with the heel portion of the element,
while the other tab does not because the element to be
arrested thereby is displaced half a pitch from the normal
position. Thus, such one-sided locking action would not be
effective when the fastener is subjected to a lateral pull
or force applied to spread its stringers apart.
SUMMARY OF THE INVENTION
With the foregoing drawbacks of the prior art in view,
the present invention seeks to provide an improved slider
for slide fastener which has means of locking the slider
positively in place against unintentional movement under the
influence of a force tending to spread open the fastener.
More specifically, the invention seeks to provide an
improved slider for a ladder-type or meandering-element
slide fastener which has a dual locking means capable of
retaining the slider in locked position even when a row of
coupling elements on one stringer is displaced or shifted
out of the normal pitch relation to an opposite row of
elements on the other stringer.
Other features and advantages of the invention will be
apparent from the following detailed description taken in
connection with the accompanying drawings which illustrate
by way of example some preferred embodiments which the
invention assume in practice.
According to the invention, there is provided a slider
for a slide fastener of the type comprising a pair of oppos-
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itely disposed stringers each carrying a row of ladder-like
or meandering coupling elements, each of which elements has
a head portion and a heel portion, the slider comprising
upper and lower wing members spaced in parallel and joined
together at their one or front ends ~y a connecting post, a
pair of opposed lateral flanges extending from each of the
wing members and inwardly directed to define with the wing
members a substantially Y-shaped guide channel for the pas-
sage of the stringers, and means of locking the slider in
place against inadvertent movement comprising a locking lug
extending from one end of at least either one of the upper
and lower flanges, a first locking projection extending from
one end of at least either one of the upper and lower
flanges opposite to the locking lug and a second locking
projection spaced one element pitch apart from the first
locking projection.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the accompanying drawings and FIG. 1
in particular, there is shown a slider generally designated
10 which is mounted on a ladder-type slide fastener F
comprising a pair of oppositely disposed support tapes T
each carrying a row of meandering or zig-zag coupling
elements E, the tape together with the coupling elements
constituting what is commonly termed a stringer. The slider
10 has two pull tabs 11, 12 pivotally mounted on its upper
and lower surfaces, respectively, so as to enable movement
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of the slider conveniently from either side of the fastener
F.
The slider 10 comprises an upper plate or wing member
13 and a lower wing member 14 which are spaced in parallel
and joined together at their one or upper ends (as viewed in
FIGS. 2 - 4) by a connecting post 15 commonly known as a
"diamond". The upper and lower wing members 13, 14 each
have lateral side flanges 16, 17 and 18, 19 respectively,
which are inwardly directed to define together with their
wings and the post 15 a substantially Y-shaped guide channel
20 for the passage therethrough of the fastener stringers.
FIG. 3 shows the upper wing member 13 as viewed from
its interior, from which it will be seen that the coupling
elements E in opposed rows on their support tapes (not
shown) are separated as they move past the post 15 upwardly
or in a direction to open the fastener F and become
interengaged as they are drawn into the guide channel 20 or
moved downwardly or in a direction to close the fastener F.
To facilitate this alternative movement of the coupling
elements E relative to the slider 10, the flanges 16, 17
(18, 19) are flared upwardly or toward the post 15 to
provide outwardly curved inner abutment walls 16a, 17a (18a,
l9a) for smooth progressive sliding contact with the heel
portions El oE the coupling elements E while the head
portions E2 thereof on one support tape are brought into or
out of engagement with those on the other mating tape as is
well known. Straight inner abutment walls 16b, 17b (18b,
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19b) are formed contiguous with the curved walls 16a, 17a
and adapted, is well known, to orient and maintain the
opposed rows of elements E in fully interengaged position.
A locking means is provided for locking the slider in
place against inadvertent movement which would otherwise
occur under the influence of a force tending to spread apart
the halves of the fastener F, the locking means comprising a
locking lug 21 formed on the upper end of one of the opposed
flanges 18 of the lower wing member 14, a first locking
projection 22 formed on the upper end of the other flange 19
and a second locking projection 23 spaced from the first
projection 22 by a distance substantially corresponding to
one element~to-element pitch P. The locking lug 21, first
end locking projections 22 and 23 are all inwardly directed
toward the channel 20 to arrest the coupling elements E and
lock the slider 10 in place and have flat abutment surfaces
21a, 22a and 23a, respectively, these surfaces being
substantially parallel with the longitudinal axis of the
slider or with the direction of linear movement of the
interengaged rows of elements to allow contact with the heel
portions El o the coupling elements with minimum of
friction.
The first projection 22 on the flange 19 is registered
in position with locking lug 21 on the confronting flange
18, but is reduced in width to provide space for the
formation of the second projection 23 which lies
substantially one pitch P apart from the first projection 22
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for purposes hereafter described.
In operation, the slider 10 with the fastener F
applied to a garment article will automatically lock itself
against inadvertent movement by the cooperative action of
the locking lug 21 and the first and second locking
projections 22 and 23, in which the lug 21 arrests the
coupling element E on one stringer close at the leading end
of its heel portion El, while the first projection 22
similarly arrests the coupling element E on the other
stringer as shown in FIG. 2 where there is no disruption in
the normal pitch relation between the two opposed rows of
elements E. In the event however that the coupling elements
E in the respective rows are shifted out of the normal pitch
relation, the particular element Ea on one stringer, which
would otherwise be located with its heel portion El at the
first locking projection 22, becomes displaced so that no
locking action takes place thereat, while the corresponding
element E on the other stringer is arrested by the locking
lug 21, in which instance the ensuing element Eb is arranged
to come into contact with the second locking projection 23
as shown in FIG. 4, thus establishing effective positive
lock of the slider 10.
The flanges 16, 17 of the upper wing member 13 are
reduced in their overall length with a view to preserving
aethetically attractive front surface appearance of the
slider 10.
Various changes and modifications may be made in the
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specific form and construction hereinabove advanced, without
departing from the scope of the appended claims.
For example, the locking lugs 21, first and second
projections 22 and 23 may be provided at both upper and
lower flanges of the slider lO in different locations as
shown in FIG. 5a, or alternatively they may be provided only
at the upper flanges as shown in FIG. 5b.
