Oct- 29» 1946.
G. suNDaAcK
L
2,410,135 y
KBTHÓD OF’IAKING SLIDE FASTBNBR STRINGERS ~
à
Fned Jah. 1. 194s
[N1/[email protected]
24,416,135!
Patented Get. 29, 1946
UNITED STATE s ¿PATEN'r
2,410,135 Á
ortica
-.
yMETHOD OF MAKING SLIDE FASTENER
STRINGERS»
Gideon Sundback, Meadville, Pa.
‘ aparcado“ January 1,1943, serial No. 470,984
in Canada October 21, i942
e crains. I (ci. as_me)
i
The invention relates to- improvements in
methods of making slide fastener stringers, The
slide fastener with which the invention is con
cerned consists of a pair of stringers, each in»
cluding a ñexible tape having a plurality of
spaced interlocking members secured to one edge
thereof, and a slider, by the movement of which
Fig. 3 isa View similar to Fig. 2 showing the
interlocking element clamped on the tape;
Fig. 4; is a view, greatly emerged, taken through
the tape of a slide fastener and showing an inter
locking element in place ready to be clamped on
the tape in accordance with one embodiment of
my invention;
’
-
Fig. 5 is a view corresponding to Fig. a showing
the interlocking element clamped on the tape;
engaged or disengaged.
‘
Fig. 6 is a view, greatly enlarged, taken through
An object of the invention is to provide a 10
the tape of a slide fastener showing an interlock
method for producing the interlocking elements
ing element in place ready to be clamped on the'
of such a fastener by die casting and to devise
tape _according to a second embodiment of my
a novel method of applying such die cast inter
along thestringers the interlocking elements are
locking elements to the fastener tape by deforma;
tion of the elements in such a manner as to over..
come the tendency ofthe brittle die-cast metal
to -fracture on deformation.
'
.
invention;
Fig. 7 is a view corresponding to Fig. 6 showing
the interlocking element clamped on the tape;
Fig. 8 is a View, greatly enlarged, taken through
the tape of a slide fastener showing an interlock
ing
element in place ready to be clamped on the
known factvthat certain die cast metals exhibit a
tensile strength, in the .as-cast condition, which 20 tape according to a third embodiment of> my ln
vention; and ~
`
may. be materially increased by reducing the
Fig. 9 is a view corresponding to Fig. 8 showing
cross-section oi the casting by compression. By
the interlocking element clamped on the tape.
providing a novel design for an interlocking ele
. Í Like characters of reference designate corre
ment casting and clamping it on the tape in a
.
novel manner which involves compressive rather 25 sponding parts in the diiîerent figures.Referring
to
Fig.
lof
the
drawing,
an
orthodox
»than tensile deformation of the casting, a fas
slide fastener comprises a'pair of tapes> l, l each
tener Stringer may be fabricated on which the
having an enlarged edge 2 on which is clamped
interlocking elements are even more firmly se- `
a plurality of interlocking elements 3. A slider
‘_ cured than by casting directly thereon, the only
'presently known method of attaching die cast 30 4 serves to engage and disengage the correspond
Yet another object is to'take advantage of th
interlocking elements to a tape. '
An additional object is to _devise a method of>
fabricating such stringers which permits the ap
ing interlocking elements of the pair-of tapes.
Each tape carrying the interlocking members is
ordinarily referred to as a Stringer.
.
According to conventional methods of making
interlocking elements, for example by anodizing 35 slide fasteners of the type illustrated, the inter
' plication of a protective or decorative finish to the
or electrolytically oxidizingan aluminum alloy of `
which the interlocking elements are made, before
application of the elements ‘to the fastener tape,
locking elements 3 are blanked, or otherwise
formed, out of strip or wire stock of nickel silver,
' brass, or any other material which has suñicient
malleability to permit the interlocking elements
without subsequent material damage to the ñnlsh. l
40 to be clamped on the thickened edge 2 of_ the.
during attachment of the elements.
_
tape without materially weakening and, in some
With the above and other objects, which will
cases, with actual improvement of the strength
hereinafter become apparent as the speciñcation
of, the interlocking elements.
proceeds, in view my invention consists of the
When made by this method, the interlocking
method, construction and arrangement, al1 as 45 elements 3, which consist of a head 5 and a pair
hereinafter more particularly described and illus
of legs 6,’6, are formed, as illustrated in Fig. 2,
trated with reference to the accompanying draw
with the legs spread apart to permit the inser
ing in which:
tion of the thickened edge 2 of the tape I and
Fig. 1 is a fragmentary plan View of a slide
are clamped on the tape by the action of a pair
fastener embodying the invention;
50 of tools 1, 'I which, on approaching, bend the
Fig, 2 is a view, greatly enlarged, taken through ' legs of the interlocking element together, around
the thickened edge of the tape, until the inter
the tape of a slide fastener and showing a con'
locking element takès the form shown in Fig. 3.
ventional interlocking element in place ready for
Under’these circumstances, the bending of the
clamping on the tape, with the interlocking ele
ment clamping tools shown schematically;
' 55. legs 6 of the interlocking element from their
2,410,135
4
.
original shape results in a combination of com
developed in the interlocking element -will be
'pressive stress on the inside of the leg section and 4
compressive in nature and, in as much as die
casting materials in particular, as well as many
tensile stress on the outside of the leg section.
In the interests of economy, however, and for
other reasons which will hereinafter become ap
parent, it is desirable to make the interlocking
other materials, are capable of withstanding
much greater compressive stresses thanv tensile
stresses, interlocking elements cast from such -
elements 3 by die casting one of the well-known
materials maybe readily clamped on a tape with
casting materials such as a zinc base alloy or
out fracture. Furthermore, as has been pointed
an aluminum base alloy. Using these materials
out, many of the die casting materials are made
it is a simple matter to cast the individual inter 10 substantially stronger. by reducing their area by
locking elements in a die or mould but, once cast,
the physical properties of these materials are
such> vthat the interlocking elements will ì only
compression, than they are as cast and the inter
locking elements applied, as disclosed, will be
substantially stronger even than those which have
stand a definite and very small maximum tensile ‘
been cast directly onto a tape.
It will also be '
deformation without fracture, or, if no fracture 15 obvious that this method of attaching die cast
takes place, without serious` diminution of the
interlocking elements to the tape avoids any ob->strength of the material.
jection to prior methods of casting the elements
According-to the present invention I obviate
directly on the tape, involving the tendering of
this difficulty by casting, by conventional meth- y
the fabric by the high temperature of the molten
ods, an interlocking element, such as i's illustrated 20 metal.
‘ _
in Figs. 4 and 9, inclusive. In the embodiment
It will also be noted that, `according to the
shown in Figs. 4 and 5 the configuration of the
invention, surface deformation of the interlock
interlocking element as cast may be substantially
ing element will be spread over an area which is
identical 'with that of a conventional interlocking
relatively much larger than when the interlock
element. In such case, if an attempt were made 25 ing element is attached to the tape, as shown in
to clamp the interlocking element on the tape
Figs. 2 and 3, by conventional methods and, fur
by the method shown in Figs. 2 and 3, the tensile
ther, such area will be normally concealed in the
stress set up in the outer section of the legs 8, 8,
finished fastener or, at least, will be relatively
would be suillcient to cause the legs to fracture
inconspicuous. This enables a relatively inelastic
or, if not to fracture, at least to be severely weak-`
protective or decorative finish to be applied to
ened. I avoid this by providing an abutment 9
the interlocking elements in bulk, such as by elec
against which the head 5 of the interlocking ele
troplating, anodizing in the case of aluminum
ment may seat while the legs 8, 8 are clamped
alloys, and even ordinary enamelling, whereafter
on the tape by the action of a pair of tools I0, I0,
the so-treated elements may be applied to the
which engage both-the outer side surfaces and 35 tape individually. In the case of moderately elas
the outer end surfaces of the legs 8 and are moved
tic finishes, the deformation of the relatively large '
by cam means, or other means, not shown, in a
surface along-the legs or in the vicinity of the
direction to simultaneously swing the legs 8 in
crotch of the element will be insufficient to cause
wardly and to urge the ends of the legstoward
rupture of the surface film, or if, as in the case
the head of the interlocking element, so that the 40 of anodized finishes, rupture does take place, it
legs are deformed by compressive action only.
As shown` in Figs. 6 and '7, the same result may
will be confined to an area on the element which
is concealed from view in the finished fastener.
be achieved by casting an interlocking element
It may be pointed out that the interlocking
elements illustrated before attachment to the
outer surfaces of the legs Il, Il are parallel and
tape are shown in the accompanying drawing
in which the head I2 is wider` than is desired in
without the casting runners which would ordi
the interlocking element after it has been applied
narily be present as the elements are ejected from
to the tape. This interlocking element is clamped
thev casting die, and that, in particular, such ele
on the tape by the action of tools I3, I3 which
ments would probably be cast in groups of rela
are moved toward each other while their surfaces 50 tively large number, interconnected by a casting
remain parallel and which, as shown in Fig. ’1,
runner, inwhich form they may be readily racked
results in compression of the head I2 only of the
and immersed in a liquid bath for electrolytic
interlocking element. It will be noted, of course,
treatment or other treatment.
that with this type of interlocking element, the
What I claim as my invention is:
configuration of the head I2 before the element 55
l. 'I'he method of making stringers for slide
is attached to the tape must be such that the
fasteners which comprises casting interlocking
changes in shape of the head during attachment
elements from metal of low tensile strength and
to the tape will result in a final configuration,
having a head anda pair of projecting legs form
as shown in Fig. 7, which is substantially the
ing a groove between the legs, inserting one edge
same as that of the conventional interlocking 60 of a tape in the groove and clamping the inter
of a novel form, .as shown in Fig. 6, in which the
element head.
,
.
_
An additional modification of the invention, as
'shown in Figs. 8 and 9. consists of providing an
'interlocking element of whichy the legs I4 are
locking elements on the tape by compressing the
metal of theelements sufficiently to bring the.
legs in contact with the tape while pressing on
the legs to prevent tension stress in the legs inci
originally straight, but divergent, to receive the 65 dental to such compression.
.
tape and which are closed onto the tape by the
2.» ’I'he method of making stringers for slid
action of tools I5.' I 5. Such tools contact the
fasteners which consists in casting interlocking
legs of the interlocking element over 4their full
elements from metal of low tensile strength and
length, and on closing will becomev parallel, as
having a head and a pair of projecting legs, form
shown in Fig. 9, to secure the interlocking ele-' 70 ing a groove between the legs, placing a tape in
ment on the tape by imparting compressive stress
the- groove and compressing the metal of the in
only to the head and a portion of thelegs thereof.
It will be obvious that,'according to these4 meth
ods of deforming interlocking elements during
clamping on the tape. substantially all the stresses 75
terlocking elements to clamp the interlocking
elements to the tape while confining the legs to
prevent tension stress in the legs incidental to
such compression.
melones
5
3. A method for producing stringere for slide
fasteners comprising casting a metal which has
- low tensile strength to form an interlocking ele
6
receive a tape therebetween, inserting a tape be-- '
tween said legs, and compressing the metal in the
head to clamp the tape between the legs, so that
tensile'stresses which lare developed in the ele
ment head of sufficient size towithstand incl-_
dental tensile stresses developed therein without 5 ment incidental to st_lch compression are coniined
tov said head and are within the elastic limit oi
exceeding the tensile strength of the head and
the head.
`
also to form a pair of tape engaging legs integral
GIDEON SUlmBACK.
with said head and suificiently spaced apart to