Note: Descriptions are shown in the official language in which they were submitted.
CA 02414643 2006-12-21
1
HOCKEY STICK BLADE WITH A BRAIDED FIBER ENVELOPE
BACKGROUND
Hockey stick blades have traditionally been made using a core to which is
glued a hosel, both made of a material such as wood, ABS or polyurethane
foam. The core and hosel are then covered by a layer of fleece or fiberglass
over
which reinforcement panels are fixed using a lamination process.. The purpose
of
the fleece or fiberglass layer is to fill in any space present between the
core, the
hosel and the reinforcement panels. As part of the laminating process, the
blade
assembly is pressed to obtain the desired curve. This construction, however,
has
some drawbacks. One of them is that the fleece layer itself does not improve
any
substantial mechanical properties of the blade. When a fiberglass layer is
used,
the problem is that the spacing between the fibers is always very small and
the
angle between the fibers is fixed. The fiberglass layer material comes in
rolls and
is thus limited in terms of possible densities and geometries.
Another known construction included the addition of a twilled or plain
weaved fiber envelope with a fiberglass layer over a laminated blade assembly
in
order to improve its mechanical properties. However, the disadvantages of such
a construction is the usual presence of wrinkles in the fiber envelope, which
lessens its potential added mechanical properties. These wrinkles are caused
by
the fiber envelope being applied to a blade having an already formed curve
combined with the fact that the blade cannot be pressed a second time. A
further
disadvantage is that the fiber envelope is on the exterior surface of the
blade and
is exposed to impacts.
Also existing is a construction where dry reinforcement panels are added
to the core and hosel, the blade curvature being formed through a resin
transfer
molding process or vacuum assisted resin transfer molding process. The
disadvantages of such a construction is that it requires complex and expensive
processes in order to obtain a consistent surface finish. Furthermore, a
different
mold is required for every blade profile and curvature, which is expensive and
means that the blade profile and curvature must be known before starting the
process. The cool down period required after the completion of the process is
another disadvantage.
CA 02414643 2006-12-21
2
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a hockey stick blade
which reduces the difficulties and disadvantages of existing processes.
In accordance with one aspect of the present invention, there is provided
a method of forming a hockey stick blade, the hockey stick blade having two
sides, the method comprising: providing a core, sliding a braided fiber
envelope
over the core, applying a promoted resin on the core and the fiber envelope,
providing at least one pre-cured reinforcement panel to at least one side of
the
blade and heat pressing the reinforcement panel towards the core so as to
secure the reinforcement panel to the blade and shape the blade.
In accordance with another aspect of the present invention, there is
provided a hockey stick blade comprising a core, an envelope of braided fiber
surrounding the core, a layer of promoted resin on the core and the fiber
envelope and at least one reinforcement panel secured on at least one side of
the blade.
In accordance with a further aspect of the present invention, there is
provided a hockey stick blade having a core having opposed top and bottom
edges, opposed first and second side surfaces spacing apart said opposed top
and bottom edges, a toe portion and a heel portion, each said side surfaces
comprising an upper perimeter disposed adjacent said top edge and a lower
perimeter disposed adjacent said bottom edge, a layer of braided reinforcing
fibers permanently disposed on each of said opposed first and second side
surfaces, pre-cured reinforcement panels having opposed proximal and distal
side surfaces, at least one pre-cured reinforcement panel being permanently
disposed on the outside of each of said layer of braided reinforcing fibers,
such
that said proximal side surface is in contact with said braided reinforcing
fibers,
said distal surface having a smooth surface, wherein the angle of said braided
reinforcing fibers varies locally on said first and second side surfaces.
In accordance with a further aspect of the present invention, there is
provided a hockey stick blade having a core having opposed top and bottom
edges, opposed first and second side surfaces spacing apart said opposed top
and bottom edges, a toe portion and a heel portion, each said side surfaces
comprising an upper perimeter disposed adjacent said top edge and a lower
CA 02414643 2006-12-21
2A
perimeter disposed adjacent said bottom edge, a layer of braided reinforcing
fibers permanently disposed on each of said opposed first and second side
surfaces, pre-cured reinforcement panels having opposed proximal and distal
side surfaces, at least one pre-cured reinforcement panel being permanently
disposed on the outside of each of said layer of braided reinforcing fibers,
such
that said proximal side surface is in contact with said braided reinforcing
fibers,
said distal surface having a smooth surface, wherein the angle of said braided
reinforcing fibers varies along said first and second side surfaces from said
heel
portion to said toe portion.
In accordance with a further aspect of the present invention, there is
provided a hockey stick blade having a laminated construction comprising in
order from the inside to the outside: a core having opposed top and bottom
edges, opposed first and second side surfaces spacing apart said opposed top
and bottom edges, a toe portion and a heel portion, each said side surfaces
comprising an upper perimeter disposed adjacent said top edge and a lower
perimeter disposed adjacent said bottom edge, a layer of braided reinforcing
fibers permanently affixed to each of said opposed first and second side
surfaces, pre-cured reinforcement panels having opposed proximal and distal
side surfaces, at least one pre-cured reinforcement panel being permanently
affixed on the outside of each of said layer of braided reinforcing fibers,
such that
said proximal side surface is in contact with said braided reinforcing fibers,
said
distal surface having a smooth surface, wherein said core, said layer of
braided
reinforcing fibers and said pre-cured reinforcement panels are assembled
together prior to said blade being heat pressed and shaped, wherein the angle
of
said braided reinforcing fibers varies Iocally on said first and second side
surfaces.
In accordance with a further aspect of the present invention, there is
provided a hockey stick blade having a laminated construction comprising in
order from the inside to the outside: a core having opposed top and bottom
edges, opposed first and second side surfaces spacing apart said opposed top
and bottom edges, a toe portion and a heel portion, each said side surfaces
comprising an upper perimeter disposed adjacent said top edge and a lower
perimeter disposed adjacent said bottom edge, a layer of braided reinforcing
fibers permanently affixed to each of said opposed first and second side
surfaces, pre-cured reinforcement panels having opposed proximal and distal
CA 02414643 2006-12-21
2B
side surfaces, at least one pre-cured reinforcement panel being permanently
affixed on the outside of each of said layer of braided reinforcing fibers,
such that
said proximal side surface is in contact with said braided reinforcing fibers,
said
distal surface having a smooth surface, wherein said core, said layer of
braided
reinforcing fibers and said pre-cured reinforcement panels are assembled
together prior to said blade being heat pressed and shaped, wherein the angle
of
said braided reinforcing fibers varies along said first and second side
surfaces
from said heel portion to said toe portion.
Other objects, aspects and advantages of the present invention will be
found in the following detailed description of a preferred embodiment of the
present invention. The description makes reference to the following
accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of a hockey stick blade core.
FIG. 2 is a schematic view of a braided fiber envelope being slid over the
hockey stick blade core.
FIG. 3 is an enlarged view an example of the braided fibers of the
envelope.
CA 02414643 2002-12-17
3
FIG. 4 is a schematic view of the core with the braided fiber envelope being
inserted between rollers.
FIG. 5 is an exploded view of the hockey stick blade.
FIG. 6 is a cross-sectional view of the resulting assembly.
DETAILED DESCRIPTION
As shown in FIG. 1, a blade (2) is the part of a hockey stick located at the
lower end of a shaft (1). Both the shaft (1) and the blade (2) are joined
together by
a hosel (3).
The construction of the blade (2) begins by providing a core (4). The core
(4) is preferably connected to the hosel (3) before the other components of
the
blade (2) are added.
The core (4) may be made of a wide range of materials. Examples are
wood, acrylonitrile butadiene styrene (ABS) plastic, polyurethane foam,
carbon,
fiberglass, aramid, vinyl ester, polyester resins, or a combination of two or
more of
the preceding. Of course, other materials with similar characteristics may be
used
as well. The core (4) is preferably initially straight, meaning that it does
not have
any pronounced curve.
If ABS is used to make the core (4) and hosel (3), then a layer of an
acetone based primer (5) is preferably applied to the core (4) and hosei (3)
at that
stage. For example, the primer (5) can be applied by dipping the core (4) and
hosel (3) into the liquid primer (5) or by spraying the primer (5) thereon.
The
primer (5) is a chemical coating used to soften the ABS surface and promote
the
bonding to the core (4) and hosel (3) of the other components of the blade
(2).
As schematically shown in FIG. 2, an envelope (6) composed of braided
fibers is opened and slid onto the core (4) and hosel (3) either manually or
mechanically. As best shown in FIG. 3, the braided fibers (14) forming the
braided
fiber envelope (6) are threaded over and under each other to form a tube. The
CA 02414643 2002-12-17
4
The fibers (14) may be made, for example, of carbon or fiberglass. The angle
between the crossing fibers (14) and the diameter of the braided fiber
envelope (6)
are selected to obtain specific mechanical properties, such as stiffness and
strength. Commercially available braided fiber envelopes (6) may be ordered
with
the desired specific parameters. Examples of such commercially available
products are the GammasoxTM braided carbon fiber envelope and the SilasoxTM
braided fiberglass fiber envelope.
Furthermore, the angle between the crossing fibers can be varied locally
over the length of the core (4) and hosel (3) in order to obtain various
desired
mechanical properties. This may be achieved by stretching the fiber braided
envelope (6) since the core (4) has not undergone any pressing operation at
this
stage. It should be noted that the envelope (6) is preferably elastically
tighten over
the core (4) once set in place, notwithstanding what is shown in the figures.
Once the envelope (6) is in place, a promoted resin (7), such as AralditeTM
epoxy, is applied. This is preferably achieved by inserting the core (4),
hosel (3)
and braided fiber envelope (6) between transfer rollers (12). The promoted
resin
(7) allows to glue the braided fiber envelope (6) to the core (4) and hosel
(3).
A pre-cured reinforcement panel (8) is added to either or both sides of the
assembly formed by the core (4), hosel (3) and the braided fiber envelope (6)
in
order to provide structural support to the blade (2 ). The reinforcement panel
(8) is
made, for example, of carbon, fiberglass or KevlarTM. The expression "pre-
cured"
refers to the fact that at least one side of the panel (8) is chemically
treated with a
heat activated adhesive. Furthermore, a pre-cured graphic panel (10), which
may
be made of similar material as the reinforcement panel (8) or may be in the
form of
a thin film of a light weight material, may also be applied to either or both
sides of
the assembly formed by the core (4), hosel (3) and the braided fiber envelope
(6).
The addition of a graphic panel (10) is for branding or advertisement purposes
as
well as added impact protection. If present, the reinforcement panels (8) and
graphic panels (10) may be added to the assembly in any order desired. In the
case where a graphic panel (10) is placed under a reinforcement panel (8), the
CA 02414643 2002-12-17
5 overlaying reinforcement panel (8) may be transparent so as to permit the
viewing
of the graphic panel (10).
Once assembled, the blade (2) is heated and pressed in order to complete
the laminating process and obtain the desired blade curvature. The desired
blade
curvature is obtained by selecting appropriately shaped plates for the press.
Finally, the blade (2) is sanded and machined to obtain the required profile.
The resulting construction of the blade (2) according to the preferred
embodiment of the present invention is shown in FIG. 6. Although the primer
(5)
and the promoted resin (7) are shown in FIG. 6 as distinct layers disposed in
the
order in which they are preferably applied, it should be noted that in the
primer (5)
if any, and the promoted resin (7) are impregnated within the fiber braided
envelope (6). The thickness of the various layers are also exagerated for the
purpose of illustration. As can be appreciated, this construction results in
the core
(4) and the braided fiber envelope (6) being protected by one or more
reinforcement panels (8), and possibly by graphic panels (10), all of which
provides higher stiffness to weight ratio than in the prior art constructions.
This is
due to the fact that in the prior art a twilled or plain weaved fiber envelope
was
added over the reinforcement panel (8), requiring a layer of fleece or
fiberglass to
fill any space between the core, the hosel and the reinforcement panel. The
fleece adds no mechanical properties to the blade while the fiberglass only
adds
minimal mechanical properties. Furthermore, the braiding in the present
invention
has better mechanical properties of the fibers than a twill or weave. Since
the
fiber braided envelope (6) and promoted resin (7) are applied between the core
(4), the hosel (3) and the reinforcement panel (8), no additional filler, such
as
fleece or fiberglass, is needed. Overall, this provides for a lighter blade
with
improved mechanical properties.
