U.S. patent application number 11/235559 was filed with the patent office on 2006-03-30 for sports boot in very stiff material.
Invention is credited to Emanuele Confortin, Andrea Fregoni.
Application Number | 20060064904 11/235559 |
Document ID | / |
Family ID | 34932793 |
Filed Date | 2006-03-30 |
United States Patent
Application |
20060064904 |
Kind Code |
A1 |
Confortin; Emanuele ; et
al. |
March 30, 2006 |
Sports boot in very stiff material
Abstract
Sports boot subassembly of the shell or collar type, which
comprises at least two parts, each comprising a flexible plastics
material injection-overmolded over a very stiff material partially
embedded in the flexible plastics material, and wherein the at
least two parts comprise an assembly surface for joining them
together.
Inventors: |
Confortin; Emanuele;
(Albaredo Di Vedelago, IT) ; Fregoni; Andrea;
(Paese, IT) |
Correspondence
Address: |
FROMMER LAWRENCE & HAUG
745 FIFTH AVENUE- 10TH FL.
NEW YORK
NY
10151
US
|
Family ID: |
34932793 |
Appl. No.: |
11/235559 |
Filed: |
September 26, 2005 |
Current U.S.
Class: |
36/117.1 |
Current CPC
Class: |
A43B 5/1666 20130101;
A43B 5/04 20130101; A43B 5/1625 20130101; A43B 5/049 20130101; B29D
35/146 20130101; A43B 5/0482 20130101 |
Class at
Publication: |
036/117.1 |
International
Class: |
A43B 5/04 20060101
A43B005/04 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 29, 2004 |
EP |
04425729.3 |
Claims
1. A process for manufacturing a sports boot subassembly of the
shell or collar type, wherein it is obtained by the assembly of
several parts, at least two of these parts being obtained by means
of the following steps: production of a blank in very stiff
material (2); injection-overmolding of a flexible plastics material
(3) over the very stiff material, linking the very stiff material
to the injection-molded flexible plastics material, in order to
form part of the sports boot subassembly:
2. The process for manufacturing a sports boot subassembly of the
shell or collar type as claimed in claim 1, wherein the step of
producing a blank in very stiff material (2) comprises a step of
thermoforming a composite sheet composed of a fiber-reinforced
thermoplastic matrix.
3. The process for manufacturing a sports boot subassembly of the
shell or collar type as claimed in claim 1, wherein the step of
producing a blank in very stiff material (2) comprises a step of
last-molding a fiber-reinforced thermosetting matrix.
4. The process for manufacturing a sports boot subassembly of the
shell or collar type as claimed in claim 1, wherein the step of
producing a blank in very stiff material (2) comprises a step of
drawing a metal sheet.
5. The process for manufacturing a sports boot subassembly as
claimed claim 1, wherein the injection-overmolding step comprises
the injection of flexible plastics material on either side of the
blank in very stiff material, at least over certain zones of its
surface.
6. The process for manufacturing a sports boot subassembly as
claimed in claim 5, wherein the injection-overmolding step
comprises the injection-molding of flexible plastics material on
either side of the blank in very stiff material, at least over
certain zones of its periphery.
7. The process for manufacturing a sports boot subassembly as
claimed in claim 6, which comprises the step consisting in
producing at least one hole in the blank in very stiff material and
wherein the injection-molding step comprises the passage of the
flexible plastics material through the hole in order to traverse
the very stiff material and to produce a fixing between the very
stiff material and the flexible plastics material.
8. The process for manufacturing a sports boot subassembly as
claimed in claim 1, wherein the injection-overmolding step
comprises the injection-molding of a thin layer of flexible
plastics material over the inner face of the very stiff
material.
9. The process for manufacturing a sports boot subassembly as
claimed in claim 1, wherein the injection-overmolding step
comprises two successive substeps of injection-molding different
flexible plastics materials.
10. The process for manufacturing a sports boot subassembly as
claimed in claim 9, wherein one of the injection-molding substeps
consists of the injection-molding of a cellular flexible plastics
material over the inner face of the very stiff material.
11. The process for manufacturing a sports boot subassembly as
claimed in claim 1, wherein the injection-overmolding step
comprises the production in flexible plastics material, on each of
the at least two parts, of complementary assembly surfaces.
12. The process for manufacturing a sports boot subassembly as
claimed in claim 11, wherein the injection-overmolding step
comprises the production of a rib in flexible plastics material on
the assembly surface.
13. The process for manufacturing a sports boot subassembly as
claimed in claim 12, wherein the step of assembling two parts
comprises the incorporation of a rib of a first part into a
corresponding groove of a second part in order to join the two
assembly surfaces of the corresponding parts.
14. The process for manufacturing a sports boot subassembly as
claimed in claim 1, wherein the step of assembling two parts
comprises the fixing of holding elements on each part on either
side of the assembly line.
15. The process for manufacturing a sports boot subassembly as
claimed claim 1, wherein a decorative element is arranged on the
blank in very stiff material and wherein said decorative element is
covered by an injection-overmolded transparent flexible plastics
material.
16. A sports boot subassembly of the shell or collar type, which
comprises at least two parts, each comprising a flexible plastics
material and a very stiff material partially embedded in the
flexible plastics material, and wherein the at least two parts
comprise an assembly surface for fixing them together.
17. The sports boot subassembly as claimed in claim 16, wherein the
very stiff material occupies at least half the total surface area
of the wall of the subassembly.
18. The sports boot subassembly as claimed in claim 16, wherein the
flexible plastics material at least partially covers the two inner
and outer surfaces of the periphery of the very stiff material.
19. The sports boot subassembly as claimed in claim 18, wherein the
very stiff material has at least one hole filled by the flexible
plastics material.
20. The sports boot subassembly as claimed in claim 16, wherein the
very stiff material has a part of its outer surface not covered by
flexible plastics material.
21. The sports boot subassembly as claimed in claim 16, which
comprises a part of the surface of its wall that comprises only
flexible plastics material.
22. The sports boot subassembly as claimed in claim 16, which
comprises a decoration arranged on the outer surface of the very
stiff material and at least partially covered by the transparent
flexible plastics material.
23. The sports boot subassembly as claimed in claim 16, wherein the
very stiff material has reinforcement ribs on its outer face.
24. The sports boot subassembly as claimed in claim 16, wherein the
very stiff material is a fiber-reinforced plastics material or a
metallic material.
25. A ski boot shell as claimed in claim 16, which comprises two
parts, wherein the flexible plastics material forms two flaps in
its top part and wherein the inner surface of the shell is covered
at least by a thin layer of flexible plastics material serving as
thermal insulation.
26. The ski boot shell as claimed in claim 25, wherein the flexible
plastics material forms reinforcements on the outer surface of the
wall.
27. A ski boot, comprising a subassembly as claimed in claim 16.
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates to a sports boot subassembly and also
to the sports boot itself, and is particularly suited to the field
of boots for boards for gliding, such as skiing or snowboarding, or
skating boots, which are subjected to significant stresses during
use and for which a particularly robust structure is required. For
example, the invention relates to subassemblies of the shell or
collar type for a ski boot. The invention also relates to a
manufacturing process.
[0002] A ski boot is a good example of a boot subjected to numerous
stresses that has to be very stiff. However, it also has to be
sufficiently flexible to guarantee the skier's comfort and to
enable him to open the boot in order to put it on and to take it
off and to enable him to flex his knees forward.
DESCRIPTION OF THE PRIOR ART
[0003] A process for manufacturing a ski boot was described in
patent EP 1295540, allowing the production of a ski boot with the
aid of several carbon-fiber fabrics connected by a resin by means
of a technique of polymerization of the resin on molds in order to
form two half-shells, prior to the joining of the two half-shells
in order, finally, to form the boot. This process makes it possible
to obtain a very stiff boot but has a first disadvantage of being
complex and costly compared to currently used injection-molding
techniques, such an injection-molding operation not being
applicable in the case of a reinforced material, a second
disadvantage of not meeting the requirements of flexibility of such
boots, and a third disadvantage of allowing only a basic design for
the outer surface of the boot. For these reasons it was quickly
abandoned.
[0004] In response to the disadvantages mentioned above, the
processes for manufacturing ski boots that are most in use nowadays
are based on processes of injection-molding of plastics materials
of polyurethane, polypropylene, polyethylene or polyamide type.
Such a solution is described in patent application EP 0903087,
which discloses a boot shell composed of a first layer in a
relatively stiff plastics material of polyurethane type partially
covered by a second layer in a more flexible plastics material, the
relatively stiff layer including thicker zones in order to form
reinforcements on certain carefully selected surfaces. A first
disadvantage of this solution is that it greatly increases the
overall weight of the boot on account of the weight of the
materials used and their considerable total thickness. A second
disadvantage stems from the fact that the performance levels
obtained in terms of stiffness are mediocre, despite the various
increased thicknesses used. A third disadvantage stems from the
fact that such boots are ill-suited to the production of adornments
on their outer surfaces. Indeed, the adornment of the outer surface
may either be achieved with the aid of specific shapes given to the
plastics material placed on the outer surface of the boot, which
gives rise to increased thicknesses of plastics for the production
of designs, these increased thicknesses generating excess weight
and an increase in the boot's stiffness, and thus, ultimately,
having a negative impact on the essential characteristics of the
boot, or be produced with the aid of marks on the outer surface of
the boot, such marks generally lasting only a short time given the
numerous aggressive influences to which they are subjected.
SUMMARY OF THE INVENTION
[0005] An object of the present invention consists in proposing a
sports boot subassembly and a process for manufacturing it that
does not present the disadvantages of the prior art.
[0006] More precisely, a first object of the present invention
consists in proposing a sports boot subassembly that makes it
possible to achieve satisfactory stiffness while conserving zones
of flexibility.
[0007] A second object of the present invention consists in
proposing a sports boot subassembly that is light in weight.
[0008] A third object of the present invention consists in
proposing a sports boot subassembly that has an attractive esthetic
appearance.
[0009] A fourth object of the present invention consists in
proposing a process for manufacturing a sports boot subassembly
that is relatively simple.
[0010] According to the concept of the invention, the wall of a
sports boot subassembly astutely combines the use of a very stiff
material and a flexible plastics material in such a way as to
achieve a good stiffness/flexibility compromise for minimum weight.
This combination of materials is, furthermore, defined in order to
allow implementation of a simple manufacturing process.
[0011] More precisely, the invention relates to a sports boot
subassembly of the shell or collar type, which comprises at least
two parts, each comprising a flexible plastics material and a very
stiff material partially embedded in the flexible plastics
material, and wherein the at least two parts comprise an assembly
surface for joining them together.
[0012] Advantageously, the very stiff material occupies at least
half the total surface area of the wall of the subassembly.
[0013] The invention also relates specifically to a ski boot shell
and to a ski boot.
[0014] It also relates to a process for manufacturing a sports boot
subassembly of the shell or collar type, wherein it is obtained by
the assembly of several parts, at least two of these parts being
obtained by means of the following steps: [0015] production of a
blank in very stiff material; [0016] injection-overmolding of a
flexible plastics material over the very stiff material, linking
the very stiff material to the injection-molded flexible plastics
material, in order to form part of the sports boot subassembly.
[0017] The blank in very stiff material may be obtained from a
composite sheet composed of a fiber-reinforced thermoplastic or
thermosetting matrix or by means of drawing a metal sheet.
DESCRIPTION OF THE DRAWINGS
[0018] These objects, characteristics and advantages of the present
invention will be set forth in detail in the following description
of a non-limiting particular embodiment with reference to the
appended figures, in which:
[0019] FIG. 1 shows a side view of the outer face of a first part
of a ski boot shell according to the invention;
[0020] FIG. 2 shows a sectional view on the axis II, of the first
part of the ski boot shell of FIG. 1;
[0021] FIG. 3 shows a side view of the inner face of the first part
of the ski boot shell of FIG. 1;
[0022] FIG. 4 is a bottom view of the two parts of the ski boot
shell according to the invention, prior to their assembly.
[0023] FIGS. 1 to 4 illustrate an embodiment of the invention for
manufacturing a ski boot shell.
[0024] FIGS. 1 to 3 illustrate a first part 1 of a ski boot shell
according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
[0025] This part 1 has a wall composed of a very stiff material 2
and a flexible plastics material 3. In this embodiment, the very
stiff material is a reinforced material composed of a
carbon-fiber-reinforced polyurethane thermoplastic matrix and the
flexible plastics material is a polyurethane of 55 Shore D
hardness.
[0026] As shown in FIG. 1, the outer surface of the wall of the
first part 1 comprises a zone 4 in which the reinforced material 2
is not covered and forms the outer surface directly in contact with
the outside of the wall, a zone 5 in which the reinforced material
is covered by the plastics material, principally as a thin layer,
and a zone 6 beyond the periphery 7 of the blank in reinforced
material 2 indicated by a dotted line where the wall comprises only
plastics material 3. Increased thicknesses 8 in plastics material
are produced on the outer surface of the part 1 with a view to
reinforcing the zones serving as pole deflectors, for example, to
form the rear and front curbs and also to produced special designs
in order to create an attractive esthetic effect. Furthermore, the
plastics material is used in a thinner thickness in order to form a
flexible flap 9 over the instep and a flexible upper part 10 at the
shin, in the above-mentioned zone 6.
[0027] As illustrated in FIG. 2, the blank in reinforced material 2
is thin and is also incorporated into the sole 11 of the shell.
[0028] FIG. 3 illustrates a view of the inner face of the wall of
the part 1, i.e. that face that will be in contact with a user's
foot in the finished shell. This face comprises a first zone where
the wall is composed of the reinforced material 2 covered by a thin
layer of plastics material 3, this zone corresponding to the zones
4 and 5 defined previously on the outer face, and a second zone in
which the wall is composed only of plastics material, which
corresponds to the zone 6 defined previously. The function of the
thin layer of plastics material which covers the reinforced
material 2 is to thermally insulate the inside of the shell--a thin
layer thus suffices. A part of the periphery of the part 1 defines
an assembly surface 12 designed to be connected to the assembly
surface of a corresponding part, as will be described in connection
with FIG. 4, which has a rib 13 running along its entire length.
This assembly surface is composed of the plastics material 3, the
reinforced material 2 coming to within a few millimeters of it. The
zone 5 on the periphery of the blank in reinforced material 2, over
which the reinforced material is embedded in the plastics material,
i.e. sandwiched by the plastics material, helps to produce a
mechanical link between the two materials. Openings 14 are,
furthermore, present in the reinforced material 2 in this zone 5,
and these are filled with the plastics material 3. These openings
14 have the primary function of producing a mechanical link between
the two materials and a secondary function of predefining
attachment points for future accessories to be fixed onto the
shell. This avoids having to perforate the reinforced material,
which could make it more fragile, giving rise to fiber rupture and
cracks.
[0029] FIG. 4 illustrates a bottom view of two complementary parts
1, 21 of a boot shell just prior to their assembly, which consists
in joining their two assembly surfaces 12 and 22 by incorporating
the rib 13 of the part 1 into the corresponding groove 23 of the
part 21. Assembly is then finalized by welding, bonding or any
other equivalent assembly process. This link based on a rib 13
makes it possible to ensure satisfactory stiffness and mechanical
strength and also provides a good seal at the link. Linking
elements 24 are fixed under the sole in order to further reinforce
the fixing of the two parts 1 and 21. The part 21 is not
illustrated in detail as it has a wall that is very similar to the
part 1.
[0030] Lastly, the shell obtained includes a reinforced material 2
that is present over more than half the total surface area of its
wall. Furthermore, except for the zones of the periphery of the
blanks in reinforced material 2 and the reinforcement zones 8, the
wall of the shell comprising the reinforced material is very thin
as it comprises the thickness of the reinforced material,
optionally covered by a thin layer of plastics material. The shell
is composed of two distinguishable parts 1, 21 connected by a
fixing means that leaves an assembly line visible on the assembly
surfaces 12 and 22.
[0031] The invention also relates to the process for manufacturing
such a ski boot shell, which thus comprises the following steps:
[0032] production of a blank in reinforced material 2 by
thermoforming a reinforced thermoplastic matrix; [0033]
injection-overmolding a plastics material 3 in order to form a
first part 1 of the shell; [0034] repeating the above two steps in
order to form the second part 21 of the shell; [0035] assembling
the two parts.
[0036] The reinforced material may consist of a polyurethane matrix
comprising carbon or glass fibers, and the plastics material may be
polyurethane. According to another solution, allowing optimum
recycling of the boot, the reinforced material may consist of
polypropylene fibers embedded in a polypropylene matrix, the
plastics material also being polypropylene. The fibers may,
according to the applications and characteristics sought, be glass,
carbon, Kevlar or polypropylene fibers.
[0037] As variant embodiments, the blank may be produced by
last-molding a fiber-reinforced thermosetting matrix or by drawing
a metal sheet. This blank may also include reinforcement ribs on
its surface.
[0038] The injection-overmolding step may make it possible to form
the top part of a shell comprising a flap 9 and a part 10 designed
to bear on the shin and also reinforcements and/or front and rear
curbs 8, the assembly surface 12 with the rib 13 and, possibly,
shapes of an esthetic nature.
[0039] As a variant embodiment, the injection-overmolding step may
comprise two successive steps of injection-molding a different
plastics material, for example, allowing the injection-molding of a
polyurethane of 65 Shore D hardness in order to form the front and
rear curbs of the interface with the ski binding, and the
injection-molding of a more flexible polyurethane of 45 Shore D
hardness in order to form the flaps. The second injection-molding
operation may also consist in the injection-molding of a cellular
plastics material over the inner surface of the boot in order to
exploit the comfort and thermal insulation properties thereof.
Assembly may be achieved by any other solution--welding, bonding or
mechanical fixing.
[0040] The invention has been described in the case of a ski boot
shell, but it could be applied to the collar of a ski boot or to a
subassembly of another sports boot.
[0041] In the embodiment described previously, the two parts of the
shell correspond to two parts obtained by cutting the shell on a
vertical plane passing through the center of the front and rear
curbs. However, any other cutting plane could be imagined. The two
complementary parts could also be designed in accordance with a
non-planar cut, the assembly surfaces not being planar. Lastly, the
concept of the invention could also be applied to the assembly of
more than two parts of a boot subassembly.
[0042] The concept of the invention thus consists of the
association of a very stiff material with a much more flexible
injection-overmolded plastics material, which we will therefore
call a flexible plastics material, the term flexible being
understood to include any plastics material of which the
flexibility is equivalent to that of a polyurethane customarily
used for boots, whose hardness is between 30 and 70 Shore D, the
expression "very stiff" being understood to be a material of
markedly greater stiffness than the flexible plastics materials
defined previously. The very stiff material may be any
fiber-reinforced thermoplastic or thermosetting matrix or any
metallic material, such as stainless steel, aluminum or magnesium.
Its function is to ensure the stiffness of the boot by its very
nature and to guarantee a light weight since it is, by nature,
light and a thin layer suffices. The injection-overmolded plastics
material has the function of providing flexibility in predetermined
zones and forming the more complex decorative and functional parts
of the boot, while fixing the two materials.
[0043] The embodiment described previously demonstrates an
advantageous combination of a very rigid material with a flexible
plastics material to form a wall of a sports boot. This combination
could, however, be different without departing from the scope of
the invention.
[0044] The flexible plastics material could also totally cover the
very stiff material on the outer face, for example, with the aim of
protecting a decoration arranged on the surface of the very stiff
material and visible from the outside by using a transparent
plastics material. The blank in very stiff material could also be
arranged in the front and/or rear curbs of the shell. Lastly, the
invention relates to any other combination of the very stiff
material and the flexible plastics material in accordance with the
concept explained above allowing the following objectives to be
achieved. [0045] a very stiff boot wall and reduced weight. To that
end the blank in very stiff material has to occupy a significant
surface area of the wall of the boot since it affords stiffness and
reduced weight. This surface area is regarded as large if it is
more than half the total surface area of the wall of the boot;
[0046] a boot wall having flexible zones and a reduced weight. To
that end, the plastics material has to occupy all zones of the boot
requiring flexibility and the total amount present on the other
zones where the very stiff material is located must be small or
zero. Thus, over the large surface area occupied by the blank in
very stiff material, the weight of the plastics material present is
markedly less than that customarily needed for prior-art plastics
boots; [0047] the manufacturing process must be simple. To that
end, the very stiff material is chosen in accordance with a blank
of a shape that is relatively simple to manufacture, and the
process of injection-molding the plastics material is used to form
the more complex shapes of the wall of the boot. In particular,
this plastics material may form a design on the outer surface of
the boot. This design gives rise to an acceptable increase in
weight, since the boot is lighter overall and its impact on the
stiffness is negligible since the stiffness of the boot is
principally determined by the blank in very stiff material. Thus,
this boot is well suited to the production of a design with the aid
of special shapes produced in plastics material on its outer
surface. It is also well suited to a decoration produced by marks,
since such marks may be arranged on the blank in very stiff
material and be covered and protected by an injection-overmolded
transparent plastics material.
[0048] Finally, the advantages of the solution are thus as follows:
[0049] great stiffness, while conserving a satisfactory compromise
between the stiffness and the flexibility required in certain
zones, a low weight, as explained above; [0050] a decoration that
can easily be produced without involving major modifications to the
functional properties of the boot; [0051] a simple manufacturing
process.
* * * * *