Note: Descriptions are shown in the official language in which they were submitted.
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llOCKEY STIC:K FORI'JED t)F CO~POSITE M~TElF21ALg;
This invention relates to hockey sticks and
similar products and more particularly to such sticks
formed in a composite manner with an outer sheath of
structural wood veneer resin bonded to an inner synthetic
5fiber layer covering a structural lightw~ight core in at
least the handle portion.
Hockey sticks have traditionally been formed of
solid wood, and hockey players are accustomed to the
weight, balance and resiliency of thesa all-wood sticks.
10However, all-wood hockey sticks frequently break under the
impacts occasioned hy normal use. In a typical
professional game about eight hockey sticks will break.
Wooden sticks are very expensive given their short active
lives and breakage during a game inconveniences the players
15and handicaps their teams.
For these reasons it has been proposed to provide
hockey sticks formed of plastic resin reinforced with
synthetic fibers such as carbon or epoxy. Within the
desirable weight limits the synthetic sticks do not have
20sufficient strength to withstand breakage and are heavier
than desired. They also do not provide the desirable
resiliency of the conventional all-wood hockey stick and
have become very expensive. Their unconventional
appearance also o~fends many traditionalists. Accordingly,
25these all-synthetic hockey sticks have seen limited use.
The present invention is directed toward a hockey
stick which provides all of the advantages of a
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conventional wooden stick in terms of per-formance
flexibility, and appearance, yet is durable enough to
resist breakage in normal use. The hockey stick of the
presant invention employs an outer sheath of structural
wood veneer overlying a sheath of synthetic fibers with
both layers impregnated and bonded together with synthetic
resin to form an integral structure. At least the handle
area of a hockey s-tick formed in accordance with the
present invention employs a central core preferably formed
of foamed plastic, balsa wood, honeycomb aluminum or
similar materials and covered with a sheath of synthetic
fibers and an overlying sheath of wood veneer, both
impregnated with synthetic resin. In another alternative
embodiment a round or rectangular thin wall aluminum or
synthetic preformed tubes which also could be filled with
foamed plastic, forms the central core. The central cores
of hockey sticks formed in a~cordance with the present
invention may also be constructed of othar lightweight,
high strength materials, such as aluminum honeycomb or
balsa wood having its grain aligned transversely to the
length of the stick.
In the preferred embodiment of the invention, the
core tapers and extends through the heel of the blade of
the stick and in an alternative embodiment the core ends at
the bottom of the handle so that the blade simply
constitutes a section of fiber-reinforced resin covered by
a resin-impregnated wood veneer sheath. This alternative
arrangement provides a very thin, highly resilient blade
allowing for superior puck handling ability. Either form
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may be produced with any desired handle to hlade angle (the
"lie" of the stick).
The present invention is also directed to a
method of forming these hockey sticks which comprises
preforming a pair of wood veneer sheaths to their desired
final shape by impregnating them with a liquid solution,
shaping them to their desired finished form in mold
sections, and drying them by allowing or causing the liquid
to evaporate. Preferably, a pressure system is used to
press the liquid impregnated sheaths against the molds to
both shape and dry the~.
Independently, a foam plastic core is molded and
covered with a fibrous reinforced fabric sheath. The
fibrous reinforcing fabric sheath is impregnated with
liquid resin and then covered by the premolded wood veneer
sections which are also impregnated with liquid resin. The
cross section of the core and the amount and thickness of
the wood, type of wood, the amount, type, weave, knit and
the direction of the cords within the fiber layers and the
core material density and physical properties may all be
varied throughout the thickness and length of the stick to
distribute the weight and strength in the most advantageous
manner consistent with the intended usage, such as
children's hockay or professional hockey or as a child's or
adult's stick.
The central core, having the general shape of the
final stick, ~ut smaller dimensions is first covered with
fiber cloth formed with high tensile strength fihers, or
continuous cords preferably of Carbon Kevlar, or glass
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materials. The fibrous reinforcement fabric covers the
entire outer surface of the core and if necessary, cap-like
sections of fibrous reinforcement fabric may be applied to
the handle end of the stick. The ~ibrous reinforcement
fabric may be woven or knitted or formed of randomly
arrayed fibers. In a preferred embodiment of the
invention, which will subs~quently be disclosed in detail,
the core is first covered with two elongated sections of
fibrous reinforcement fabric, each extending the full
length of the stick, and each having a width along its
length so that when the two sections are laid over the core
their edges abut, forming two seams on diametrically
opposed sides of the stick. Alternatively, the ed~es of
the sections may overlap one another. The fabric from
which these sections are formed preferably includes at
least two groups of fibers or continuous cords. One group
runs longitudinally so as to extend along the length of the
stick. The other fiber group extends at right angles to
the first group, or circumferentially about the stick, or
alternatively, the fabric may include second and third
fiber groups arrayed at angles of 45O to the longitudinally
extending fibers on both sides, so that the 45O cords
extend at 90oto one another. Preferably, these fir.st two
sections, which abut the core, are covered by a pair of
similar sections displaced 90o radially relative to the
first section so that each of the second sections is
centered on one of the longitudinal seams formed between
the underlying first sections.
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These elongated fibrous reinforcement fabric
sections are khen preferably covered with elongated strips
of fibrous reinforcement fabric which is spirally wound
over the elongated sections. The fiber layer may be
impregnated with resin prior to lamination through the use
of pre-pegs or used in the liquid state during lamination.
Any of khe wide variety of commercially available synthetic
resins for use in forming fibrous reinforcement fabric may
be employed. Before the resin is set the fiber-resin
coated core is ready to receive the outer structural wood
layers or layer which are resin-coated to ~nsure proper
bonding. The wood layers are in the form of one or more
planks or strips which are preformed and cut to desired
shape and size. The composite is then pressed toyether
through the use of split molds, vacuum hag or the like.
The molds may also be heated to accelerate cure and allow
the use of exotic bonding resins which cannot be worked at
room temperature.
In the preferred embodiment the wood veneer
strips and spirally wound tape extend slightly over the top
end of the stick covering the core at the top end. The
wood veneer planks are preferably cut from a single sheet
so that the grain structures of adjacenk planks match one
another giving the finished stick the appearance of a
conventional wood stick. The wood grains are preferably
arrayed longitudinally along the length of the stick so
that the tensile strength and impact resistance of the wood
in the longitudinal direction is maximized.
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The formed sections may be pressed against the
core in split dies while the resin cures. The superior
performance of the stick and resistance to breakaye is
believed to arise by virtue of the fibers of the wood,
which are relatively resilient, distributing impact loads
on the stick over relatively large numbers of the
underlying synthetic fibers and strengthening the synthetic
fibers to prevent their collapse in a compression/impact
mode.
The density of the central foam core may be
varied along the length of the stick to provide any
combination of desired weight, balance and resilient
characteristics.
The finished stick has the appearance of a
traditional all-wood stick.
Other applications and advantages of the present
invention will be made clear by the following detailed
description of several embodiments of the invention. The
description makes refPrence to the accompanying drawings in
which:
FIGURE 1 is a perspective view of a hockey stick
formed in accordance with the present invention;
FIGURE 2 is a detailed view of a section along
the length of the hockey stick of FIGURE 1 with portions of
the surface broken away to illustrate the interior
construction;
FIGURE 3 is a cross-sectional view of the handle
of the hockey stick of FIGURE 1, taken along lines 3-3 of
FIGURE 1;
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FIGURE 4 is a cross-sectional ~iew through the
blade of the hockey stick of FIGURE 1, taken along lines 4-
4 of FIGURE 1;
FIGURE 5 is a cross~sectional view through a
handle of an alternative embodiment of the .invention
employing two layers of wood veneer in the outer sheath of
the handle, with their grains oriented normally to one
another; and
FIGURE 6 is a persp~ctive v.iew of a
complementary pair of wood veneer preforms created in
connection with the process of the present invention is for
use in forming the hockey sticks of the present invention.
Referring to the drawings, a hockey stick of the
present invention, generally indicated at 10 in Figure 1,
preferably has the appearance of a normal hockey stick and
consists of an elongated handle section 12 usually four to
five feet in length of a generally rectangular cross
section. Normally, the cross section of the handle section
12 is constant along its length, but it may vary along it~
length, as, by way of example, tapering slightly along its
length so that the apparatus is somewhat larger than the
lower end.
A blade section 14 formed integrally with the
lower end of the handle extends outwardly from the lower
end of the handle so that an obtuse angle, typically in the
range of 100 degrees is formed between the handle 12 and
the blade 14 The blade 14 is typically thinner and wider
than the handle section 12 and may taper along its length
so that its free end is slightly wider than the end joined
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to the bottom of the handle 12. The angle between the
handle 12 and the blade 10, known as the "lie" of the stick
may be varied, 50 that hockey sticks are made available
with slightly different lies.
Figure 2 illustrates the composite construction
of the handle 12 of the hockey stick 10. The outer surface
of the stick consists of a sheath of structural wood veneer
16, preferably having a thickness in the range of 1/16 -
3/16 of an inch. The veneer is preferably formed of a
relatively hard wood such as ash or oak and the grain of
the outer sheath is arranged to extend longitudinally along
the length of the handle. The wood veneer layer 16
preferably extends over the blade area 14 giving the entire
hockey stick the appearance of a conventional all-wood
stick. Alternati~ely, in other embodiments of the
invention only the handle 12 may be covered with the wood
veneer. The butt end 18 of the stick may be covered with
veneer or it may be capped by plastic ~not shown) or the
layers which form the stick may be cut off short so that
the butt end 18 exposes a typical cross section through the
handle.
The outer wood veneer layers 16 overlies a sheath
20 consisting of a layer of fibrous reinforcing fabric such
as glass, Kevlar carbon, epoxy or various combinations,
reinforcing a synthetic resin such as epoxy. The resin
layer further impregnates th~ outer wood veneer sheath 16
and joins the wood veneer 16 in the underlying fiber layer
20 into an integral structur~. Th~ resin preferably covers
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the outer surface of the wood veneer 16 to protec-t and seal
the wood fibers.
The synthetic fibers forming part of the layer 20
are typically relatively brittle and the fibers of the
outer wood sheath 16 act to distribute impact loads over a
number of the fibers so as to prevent the fibers from
breaking in tension compression loads. The wooden sheath
also stiffens the stick and gives it longitudinal strength
and stiffness.
The fiber-reinforced resin sheath 20 overlies the
central core 24 which is preferably formed of a synthetic
foam such as urethane or polyvinyl. The foam may either be
opened or closed cell. The foam core, covered with the
fiber-reinforced resin sheath 20, in turn covered by the
outer wood veneer layer 16, creates a handle that is
lightweight yet has a great strength and designed
stiffness.
In alternatives embodiments o~ the invention, the
core 24 may be formed of materials other than foam plastic
or may include foam plastic with other elements~ For
example, Figure 5 illustrates an alternative form of
construction for the handle wherein the core is formed by
a hollow aluminum extrusion 26 having its central void
filled with foam plastic 28, or could be hollow. The
aluminum tube 26 is covered by a layer of fiber-reinforced
resin 30 and an outer layer of wood veneer 32. The edges
of all of the elements are preferably rounded to give the
handle a generally rectangular/oval configuration.
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It should be understood that in alternative
embodiments of the invention, the central core, as
exemplified by the foam core 24 in the embodiment of
Figures 1-3 or the foam-filled aluminum tube 26 of the
embodiment of Figura 5, could be replaced by alternative
materials such as a hollow metal tube, metal honeycomb or
the like.
In the preferred embodiment of the invention
illustrated in Figures 1-4 the central core terminates on
a taper and allows unbroken cords continuation from handle
to blade at the joinder of the handle 10 to the blade 1~,
and blade 14, illustrated in cross section in Figure 4,
consists of the layer of wood veneer 16 overlying and
bonded to the central element 20 of fiber-reinforced resin.
The blade 14 is thus more resilient than the handle 12; a
desirable characteristic which is achieved in all wood
sticks by virtue of the blade being thinner than the
handle.
In alternative configurations the wood veneer
outer cover ~6 of the handle 12 could terminate at the
blade, and the blade could constitute either a simple layer
of resin reinforced fiber or resin reinforced fiber
overlying a thin core element such as a sheet of aluminum
or the like.
Another alternativa configuration would employ a
pair of wood ~eneer sheets as the two outer layers of the
stick, or the handle, with grains of the two sheets
arranged orthogonally to one another to provide strength in
two directions.
The hockey sticks of the present invention are
preferably formed by a method which involves the formation
of a pair of complementary wood veneer preforms illustrated
as 40 and 42 in Figure 6. These preforms are shaped so
that they may be joined together at their edges to form
the skin of a completed hockey stick. The preforms 40 and
42 may be formed of either single layer or a double layer
of the wood veneer. In the case of double layers, the
outer layer has its grain arranged longitudinally to the
length of the preform and the inner layer preferably has
its grain arranged opposite to the first. The preforms are
cut to an appropriate shape, are then soaked with a liquid
such as water, alcohol or the like and are placed in
suitably shaped molds (not shown). The preforms are then
allowed to dry, preferably in preheated dried air, or their
drying is accelerated by placing pressure over the preforms
and heating the molds.
Independently, a core covered by fibrous
reinforcing fabric is formed and both the fiber and the
dried wood preform are impregnated with liquid resin and
joined together so that the preforms cover the core. This
may be done using molds or a vacuum bag. After the resin
is fully set, the hockey stick o~ the present invention is
completed.
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