U.S. patent application number 14/024998 was filed with the patent office on 2014-03-13 for process for the fabrication of interconnecting elements for a slide fastner.
This patent application is currently assigned to RIRI SA. The applicant listed for this patent is RIRI SA. Invention is credited to Vasco Zagaglia.
Application Number | 20140068898 14/024998 |
Document ID | / |
Family ID | 47143512 |
Filed Date | 2014-03-13 |
United States Patent
Application |
20140068898 |
Kind Code |
A1 |
Zagaglia; Vasco |
March 13, 2014 |
PROCESS FOR THE FABRICATION OF INTERCONNECTING ELEMENTS FOR A SLIDE
FASTNER
Abstract
Method for manufacturing interconnecting elements for a slide
fastener, comprising the steps of producing interconnecting
half-elements provided with a predetermined three-dimensional
shape, by means of punching of said half-elements from a sheet, and
forming said interconnecting elements by joining together
respective pairs of half-elements.
Inventors: |
Zagaglia; Vasco; (Chiasso,
CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
RIRI SA |
Mendrisio |
|
CH |
|
|
Assignee: |
RIRI SA
Mendrisio
CH
|
Family ID: |
47143512 |
Appl. No.: |
14/024998 |
Filed: |
September 12, 2013 |
Current U.S.
Class: |
24/381 ;
29/410 |
Current CPC
Class: |
Y10T 24/25 20150115;
B21D 53/52 20130101; Y10T 29/49785 20150115; A44B 19/06 20130101;
A44B 19/46 20130101; A44B 19/403 20130101 |
Class at
Publication: |
24/381 ;
29/410 |
International
Class: |
B21D 53/52 20060101
B21D053/52; A44B 19/06 20060101 A44B019/06 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 12, 2012 |
EP |
12184083 |
Claims
1. A method for manufacturing interconnecting elements for a slide
fastener, comprising: producing interconnecting half-elements with
a predetermined three-dimensional shape by punching of the
half-elements from a sheet; and forming the interconnecting
elements by joining together respective pairs of half-elements.
2. The method according to claim 1, wherein the sheet of material
is a flat sheet or plate with a rectangular cross-section.
3. The method according to claim 1, further comprising plastic
deformation of the sheet of material so as to obtain
three-dimensional shaping of the half-elements before the punching
step.
4. The method according to claim 1, wherein punching of the
half-elements from the sheet of material is performed along a
heightwise direction of the interconnecting element, the direction
being a front-rear direction which is perpendicular to a plane of
flanking strips when the interconnecting element is applied to the
slide fastener.
5. The method according to claim 4, wherein a joint between
half-elements is performed by joining together joining surfaces
perpendicular to the heightwise direction.
6. The method according to claim 1, wherein the half-elements are
identical to each other.
7. The method according to claim 1, wherein differently shaped
first half-elements and second half-elements are made, and wherein
each interconnecting element is formed by joining a first
half-element together with a second half-element.
8. The method according to claim 1, wherein the joining together of
half-elements is performed by at least one of welding, brazing,
gluing or mechanical fixing.
9. The method according to claim 1, wherein material of the sheet
is a metal or metal alloy suitable for punching.
10. An interconnecting element for a slide fastener obtained by the
method according to claim 1 and comprising two half-elements made
by punching and joining together.
11. The interconnecting element according to claim 10, further
comprising a portion or a surface which reproduces a logo, a brand
name or part thereof.
12. A slide fastener or an article comprising a slide fastener,
comprising interconnecting elements according to claim 10.
Description
FIELD OF APPLICATION
[0001] The invention relates to the manufacture of interconnecting
elements for a slide fastener (zip fastener). The invention in
particular relates to the manufacture of interconnecting elements
which have a complex shape, for aesthetic purposes or for
personalization of the slide fastener.
PRIOR ART
[0002] A slide fastener as known comprises essentially two flanking
strips which carry respective rows of interconnecting elements,
commonly called teeth or tines, and a slider for engaging and
disengaging the aforementioned elements. The fastener may also
comprise a top stop and a bottom stop for stopping the slider.
[0003] Punching is a widely used technique for manufacturing
interconnecting elements, especially if they are made of a metallic
material. The prior art in the field essentially envisages that
each element is punched as a single piece from a flat metal sheet,
also termed plate. Punching is generally performed in several
stages; prior to punching and associated separation from the sheet,
it is also known to make some machining steps involving a plastic
deformation of the strip, such as drawing or coining, in order to
obtain particular shapes, such as projections and recesses for
engagement between one element and another.
[0004] A major advantage of the punching process is the provision
of huge production volumes at a low cost. Typically a punching
press can perform thousands of strokes per minute and produce tens
of teeth per stroke. This remarkable productivity is highly
appreciated in the manufacture of items like teeth of a slide
fastener, which have small dimensions and are produced in a large
number. Moreover, there are some materials, such as brass, which
are unsuitable for other processes (e.g. injection moulding) and
for which punching is particularly suitable. Punching from a brass
strip is common in the field.
[0005] Production by means of punching from a flat sheet still has,
however, a major drawback being unsuitable for making
interconnecting elements with a complex shape. In fact, the
elements have surfaces corresponding to the thickness of the strip
which, after punching, are necessarily flat. In the prior art, in
particular, the visible surfaces of the interconnecting elements
are precisely the aforementioned flat surfaces cut in the thickness
of the strip. Moreover, the various drawing, coining and other
machining steps are easily performed only on the two parallel faces
of the sheet, and do not allow obtention of complex
three-dimensional shapes.
[0006] Subsequent machine-finishing of the teeth is not convenient
because it would require processing one-by-one a large number of
parts with small dimensions of the order of a few millimetres. A
partial solution to the problem would consist in starting from a
shaped sheet, but this solution is not appealing because it would
involve very high plant costs.
[0007] For these reasons, in the prior art, production of a complex
three-dimensional shape by means of punching is not considered to
be feasible. Other machining techniques are known (e.g.
machine-tool processing, precision casting, etc.) which can obtain
elements of various shapes, but these techniques do not have the
production capacity of punching and involve higher costs.
[0008] Another limitation of punching consists in the difficulty of
punching a strip with a large thickness. In the prior art punching
is used normally for a small thickness, usually not greater than
about 1-1.5 mm; punching from a strip of large thickness (e.g.
>2 mm) is difficult and may cause deformation of the teeth. This
deformation may be unpleasant and/or may adversely affect
operation.
[0009] There is a constantly growing demand for slide fasteners
with interconnecting elements made of high-quality material and/or
with a complex three-dimensional shape, in particular for aesthetic
purposes. For example, there is an increasing demand for slide
fasteners equipped with interconnecting elements having a
customized or recognizable shape, or reproducing a logo or brand.
This requirement is frequent particularly for slide fasteners
intended for articles of clothing, bags, fashion articles, etc. The
demand for personalization relates in particular to surfaces of the
teeth which remain visible when the fastener is closed. Production
by means of punching is not considered able to meet this market
demand in a satisfactory manner.
[0010] The technical problem forming the basis of the invention
emerges even more clearly when considering FIGS. 8 and 9 which show
an interconnecting element or tooth 100 punched according to the
prior art. The tooth 100 comprises a head portion 101 intended to
engage with another tooth by means of a projection 103 and an
opposite recess 104, said projection and recess being obtained by
plastic deformation of the plate. The base portion comprises two
arms 102 which may be crimped onto a peripheral edge of the
flanking strip. Broken lines in FIG. 9 indicate the sheet of
material B; the working direction of the cutting punch is indicated
by the arrow T.
[0011] It can be understood that, since the surface 105 is cut
within the thickness s of the sheet, it cannot be shaped or
customized for aesthetic purposes unless expensive machining
operations are subsequently performed on each single element. In
substance, the element 100 may be conveniently shaped only in the
direction perpendicular to the plane of the metal sheet, for
example making the projection 103 and the recess 104 shown in the
figure.
[0012] This means that the teeth have necessarily an engaging
direction (that is the sliding direction of the slider in the
finished fastener) which is parallel to the punching direction T
(FIG. 9), leaving the smooth surfaces 105 visible. Moreover, as
mentioned above, a processing as seen in FIG. 9 is applicable in
practice only when the plate thickness is small (about 1 mm), thus
having a limited versatility.
SUMMARY OF THE INVENTION
[0013] The invention is aimed to solve the abovementioned problem
by providing a method for manufacturing interconnecting elements
for a slide fastener, by means of which it is possible to obtain
elements with complex three-dimensional shapes, while maintaining
the production capacity and the low costs of the known process of
punching from a flat sheet.
[0014] The idea underlying the invention is to obtain, by means of
punching, parts forming a half of a single interconnecting element.
This ensures a greater freedom in definition of the shape of the
elements, compared to punching in a single piece.
[0015] The aim of invention is therefore achieved by means of a
method for manufacturing interconnecting elements for a slide
fastener, characterized in that it comprises the steps of: [0016]
producing interconnecting half-elements provided with a
predetermined three-dimensional shape by means of punching of said
half-elements from a sheet; [0017] forming said interconnecting
elements by joining together respective pairs of half-elements.
[0018] Advantageously, said sheet of material is a flat sheet or
plate with a rectangular cross-section.
[0019] More specifically, the method comprises preferably one or
more steps of plastic deformation of said sheet of material, in
order to define the geometry of the half-elements prior to punching
step and corresponding separation from the sheet. The geometry of
the half-elements is defined while respecting the necessary
aesthetic and functional constraints (meshing). For example,
surfaces of the half-elements are formed on the sheet with a
suitable pitch (relative distance) by means of coining, drawing or
other machining operations which precede final punching of the
workpiece (half-element).
[0020] Preferably the punching is performed in a heightwise
direction of the interconnecting element, said heightwise direction
being defined as a front-rear direction of the slide fastener,
which is perpendicular to the plane of the flanking strips when the
element is applied to the fastener itself. In this way punching
defines a flat bottom face of the half-elements which corresponds
to a bottom face of the sheet and which can be used for the
joining. In other words, the joining plane of two half-elements is
preferably a middle plane which coincides with the plane of the
flanking strips of the slide fastener and is also substantially
parallel to the direction of engagement of the teeth and sliding
direction of the slider.
[0021] In some embodiments of the invention, the half-elements are
identical to each other. In other embodiments, first half-elements
and second half-elements with a different, preferably symmetrical,
shape are produced, each element being formed by joining a first
half-element with a second half-element. The first half-elements
and the second half-elements may be obtained, respectively, from a
first and a second sheet of material along separate punching lines
and then fed to a joining machine or line.
[0022] Joining the pairs of half-elements is performed preferably
with one of the following techniques, which are indicated by way of
a non-exhaustive example: welding; brazing; gluing; mechanical
fixing.
[0023] Conventional welding (without any filler material) may be
applied for example by performing a spot-welding. Brazing is
performed using a filler material with a lower melting point than
material of the teeth, and is particularly preferred because it
does not cause local melting of the teeth, nor does it modify their
shape, which as is known must be precise to ensure operation and
smooth action of the slide fastener. Mechanical fixing, if used,
may be performed for example using screws, rivets or cusps/seats.
Mechanical fixing may be preferred for elements of a large
size.
[0024] The material of the interconnecting elements may be any
material suitable for punching. Particularly preferred are metallic
materials or metal alloys suitable for punching, including brass or
even silver and gold, for use in exceptional luxury articles.
[0025] The joining of pairs of half-elements may be followed by
further finishing operations which hence are carried on the already
formed interconnecting elements, and which may comprise
galvanization, polishing or other.
[0026] The great advantage of the invention is that the
interconnecting elements may have complex three-dimensional shapes,
practically without limitation, while continuing to use the
punching process and the related advantages of high productivity
and low cost. In fact, the half-elements can be made with a complex
shape, comprising inclined surfaces, curved surfaces, parts tapered
from bottom to top, etc. If punching the interconnecting elements
as single pieces, as in the prior art, these shapes would not be
possible. The invention does not require the use of a shaped sheet,
but on the contrary allows realization of sophisticated shapes
starting from a flat strip, owing to the manufacture of the
elements as two halves.
[0027] Another advantage consists in that, by punching the
half-elements separately and subsequently joining them together, it
is possible to provide interconnecting elements with a size
(corresponding to the thickness of the original strip) which is
twice that possible with the prior art, for a given maximum
thickness compatible with the punching.
[0028] The invention therefore expands the possibilities of
aesthetic personalization of the slide fastener, while maintaining
a low industrial cost and a proven and reliable process, that is
the punching process. This will emerge more clearly hereinbelow,
with the aid of examples which are shown by way of a non-limiting
example.
DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 shows some parts of a generic slide fastener.
[0030] FIG. 1A is a detail of FIG. 1 which shows the
interconnecting elements or teeth of a generic slide fastener.
[0031] FIG. 2 shows a perspective view of an example of an
interconnecting half-element which can be obtained with the present
invention.
[0032] FIG. 3 is a top plan view of the half-element according to
FIG. 2.
[0033] FIG. 4 is a view of the half-element according to FIG. 2
from a different angle.
[0034] FIG. 5 shows an interconnecting element obtained from
joining together of two half-elements according to FIG. 2.
[0035] FIG. 6 is a block diagram illustrating a method for
manufacturing the strip portions of a slide fastener, which
includes the manufacture of the interconnecting elements according
to the present invention.
[0036] FIG. 7 is a an alternative diagram to that shown in FIG. 6
for the manufacture of different half-elements joined in pairs to
form the interconnecting elements.
[0037] FIGS. 8 and 9 show an interconnecting element obtained by
means of punching according to the prior art.
DETAILED DESCRIPTION
[0038] FIG. 1 shows a typical slide fastener or zip fastener
indicated generally by 10. The slide fastener 10 comprises two
flanking strips 12 with rows 13 of interconnecting elements (teeth)
14. A slider 15 and a top stop 16 are also shown.
[0039] For the purposes of the description of the invention, the
height of an interconnecting element 14 is defined as the dimension
of the element in an inner-to-outer direction H of the slide
fastener, which is perpendicular to the plane of the flanking
strips 12 when the slide fastener is ideally arranged as shown in
FIG. 1. The length L of an element 14 is defined in a transverse
direction of the flanking strips 12, and the width W of an element
is defined in the longitudinal direction of the flanking strips 12
(FIG. 1A).
[0040] The interconnecting elements 14 are each made by joining
together two half-elements obtained by means of punching from a
sheet or plate which is advantageously flat.
[0041] FIGS. 2-4 show a half-element 20 according to one of the
modes of implementing the invention. Said half-element 20 comprises
essentially a flat bottom face 21 (FIG. 4) which defines a joining
plane for joining with another half-element; a head portion 22, a
root portion 23, a top face 24 and tapered sides 25.
[0042] The head portion 22 of the half-element is intended to form
(together with another half-element) the head of the
interconnecting element 14 that is the part intended for meshing.
The root portion 23 is intended to form the base of the element
that is the part for fixation to flanking strips 12.
[0043] The sides 25, as can be noted in the figures, connect the
bottom face 21 to the top face 24 and are formed, for example, by a
plurality of inclined and/or curved faces, providing the
half-element with a complex three-dimensional shape. Preferably the
sides 25 are tapered in the heightwise direction H of the
half-element 20, perpendicular to the flat bottom face 21.
[0044] FIG. 3 shows the punching edge 26, the punching being
performed perpendicularly to the plane of said FIG. 3.
[0045] The complex shape of the half-element 20, in particular the
sides 25 and the root portion 23, is generated by means of
plastic-deformation machining performed directly on the sheet
before punching and/or by means of suitable shaping of the cutting
punch and die. For example, the root portion 23 may be shaped by
means of coining the sheet from below.
[0046] FIG. 5 shows an example of an interconnecting element or
tooth 14 obtained by joining together two half-elements 20. The
element 14 has a head portion 30 and a substantially Y-shaped root
portion 31, with two arms 32 to be crimped onto the flanking strips
12 or onto a suitable cord, in accordance with details which are
known per se. For the purposes of the present invention it must be
pointed out that the engagement between the elements occurs
substantially in the middle zone of the head 30, in the vicinity of
the joining plane. The faces 24, which are defined by the tapering
of the sides 25, have practically a free shape, which may have an
aesthetic function, reproducing for example a logo, a brand name or
part thereof.
[0047] It must also be noted that the shape of the element 14, as a
whole, could not be obtained by means of conventional punching from
a flat sheet (cf. FIGS. 8, 9) since it would be practically
impossible to form the two tapered sides 25 and the inclined shaped
portions 23.
[0048] The example shown in FIG. 5 relates to an embodiment in
which the two half-elements 20 are identical, but are slightly
staggered, such that the head of the tooth has laterally a
projection 33 and a recess 34. In accordance with various
embodiments, the two half-elements which form a tooth 14 may be
identical or different from each other, preferably symmetrical.
[0049] FIG. 6 is a block diagram illustrating a mode for
manufacturing a slide fastener according to the invention. Block 50
represents the manufacture of suitably shaped half-elements 20 by
means of punching from a flat sheet of material, for example brass.
Block 51 represents the joining together of pairs of half-elements
20 using a suitable technique such as brazing, welding, gluing,
mechanical fixing or other technique. Block 52 represents one or
more treatments for finishing the elements 14 thus obtained, such
as coating, polishing, etc., which may be performed depending on
the requirements. Block 53 represents the application of the
finished elements onto the flanking strips 12.
[0050] FIG. 7 shows a variant where each interconnecting element 14
is formed by two half-elements 20a, 20b with a non-identical shape,
which are for example symmetrical. The elements 20a, 20b may be
produced separately using two punching lines 50a, 50b and converge
in a joining line 51. Said line 51 for example comprises a suitable
matrix or template which allows correct positioning of an element
20a and an element 20b for joining together, for example by means
of brazing, gluing, etc.
* * * * *