Note: Descriptions are shown in the official language in which they were submitted.
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HOCKEY STICK SHAFTS, HOCKEY STICKS,
AND METHODS OF MAKING THEM
BACKGRQUND OF THE INVENTION
Field of the Invention
s The present invention is directed to shafts for hockey sticks and
methods of making shafts for hockey sticks.
Backaround of the IrZ ention
There is an ongoing need for improving various properties of
hockey sticks. Such properties include the strength, stiffness, flexibility,
to damage tolerance, temperature resistance, vibration damping profile, and
weight. Also, there is an ongoing need for improving various other
characteristics of hockey sticks, as discussed herein.
SUMMARY OF THE INVENTION
In accordance with the present invention, there are provided
z5 improved methods of making hockey stick shafts and hockey sticks, as well
as improved hockey stick shafts and improved hockey sticks.
Hockey stick shafts made of aluminum exhibit relatively low
vibration damping, and so a great deal of impact energy is transferred to
(and/or felt) by the player holding such a stick (e.g., particularly when the
2 o player takes a "slapshot"). Hockey stick shafts made of wood or polymeric
materials exhibit temperature resistances which are generally lower than
hockey stick shafts made of aluminum alloys. As a result, where heat is
applied to a wooden or polymeric shaft in order to bond the blade portion of
the hockey stick to the shaft, themnally induced damage can occur to the
shaft.
2s Aluminum alloys and wood typically have low yield strengths (or
proportional
limits), and so permanent deformation (bending) can occur when relatively low
forces are applied.
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The present invention provides a hockey stick shaft and a
hockey stick, as well as methods for making them, which provide significant
improvements over previously known shafts, sticks and methods, as
discussed in more detail below.
s In accordance with a first aspect of the present invention, there
is provided a method of making a hockey stick shaft (and the hockey stick
shaft formed thereby), comprising:
(a) forming a laminate comprising a plurality of layers, each of
the plurality of layers comprising composite material comprising fibers and
to resin, the laminate having at least a first transverse edge and a second
transverse edge;
(b) bringing into contact with the first transverse edge of the
laminate a metallic tip having a first tip surface which contacts the first
transverse edge; and
1s (c) curing the resin, thereby bonding the plurality of layers to
each other and bonding the first tip surtace of metallic tip to the first
transverse
edge of the laminate.
In accordance with a second aspect of the present invention,
there is provided a method of making a hockey stick shaft (and a hockey stick
2 o shaft formed thereby), comprising:
(a) forming a laminate comprising a plurality of layers, each of
the plurality of layers comprising composite material comprising fibers and
resin, the laminate having at least a first transverse edge and a second
transverse edge;
25 (b) curing the resin; and
(c) attaching a metallic tip to the first transverse edge.
In accordance with a third aspect of the present invention, there
is provided a method of making a hockey stick shaft (and a hockey stick shaft
formed thereby), comprising:
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(a) fom~ing a hollow Laminate comprising a plurality of layers of
composite material and at least one metallic layer, each of the plurality of
layers of composite material comprising fibers and resin, the laminate having
interior and exterior surfaces, at least a first transverse edge and a second
s transverse edge; and
(b) curing the resin, thereby bonding the plurality of layers of
composite material and at least one metallic layer to each other.
In accordance with a fourth aspect of the present invention, there
is provided a hockey stick shaft comprising:
i o a composite portion having a hollow structure, the composite
portion comprising an interior surface and an exterior surface, and at least a
first edge, the composite portion comprising fibers and resin; and
a metallic tip, the metallic tip having a first tip surface,
the first edge of the composite portion being attached to the first
15 tip surface of the metallic tip.
in accordance with a fifth aspect of the present invention, there
is provided a hockey stick shaft comprising a hollow laminate comprising
composite material and at least one metallic layer, the composite portion
comprising fibers and resin.
2 o The present invention is also directed to hockey sticks which
include a hockey stick shaft as described herein, and to methods of making
such hockey sticks.
BRIEF DESCRIPTION~F THE DRAWING FIGURES
Fig. 1 is a perspective view of a hockey stick shaft made in
2s accordance with an embodiment of the first or second aspect of the present
invention.
Fig. 2 is a cross-sectional view of a hockey stick shaft made in
accordance with an embodiment of the first or second aspect of the present
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invention.
Fig. 3 is a perspective view of a hockey stick shaft made in
accordance with an embodiment of the third aspect of the present invention.
Fig. 4 is a cross-sectional view of one wall of a hockey stick shaft
s made in accordance with an embodiment of the third aspect of the present
invention.
Fig. 5 is a perspective view of a conventional hockey stick shaft
and blade.
DETAILED DESCRIPTION OF THE INVENTION
1 o The following discussion includes descriptions of preferred
materials and method steps for making the items in accordance with the
present invention, as well as features provided by the methods and products
according to the present invention.
In accordance with the present invention, a laminate is formed
15 which comprises a plurality of composite material layers, each composite
material layer comprising fibers and resin.
A wide variety of materials can be used for the fibers in the
composite layers used according to the present invention, those of skill in
the
art being familiar with many different types of fibers having various
properties.
2 o In general, any fiber which provides reinforcement may be suitable for use
in
the present invention. For example, preferred fibers include graphite, glass
and Kevlar. Examples of suitable materials include organic, inorganic and/or
multiphase fibers and the fibers may be unidirectional or woven. Organic
fibers include, but are not limited to, fibers made of carbon, boron, graphite
2s and polymers such as olefin, nylon and aramid. Inorganic fibers include,
but
are not limited to, fibers made of glass, metal, alumina and ceramic.
Multiphase fibers include, but are not limited to, fibers made of
boron/tungsten,
boron coated carbon and silicon carbide. The particular composite materials
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used will depend upon the desired characteristics of the completed hockey
stick shaft such as flex, strength, durability, toughness, kickpoint, torque,
weight, shock dampening, ease of manufacturing and cost.
The resin used according to the present invention can be
5 selected from the wide variety of resins known to those skilled in the art,
including but not limited to polymeric resins. It is preferred that the resin
be
selected such that the curing step can be conducted at or below 350 °F.
Preferred examples of suitable composite materials include
graphite, glass or Kevlar in either unidirectional prepreg tape or bi-
directional
to prepreg fabric forms. An example of a suitable composite material which may
be used is Newport NCT-301.
In accordance with the first and second aspects of the present
invention, a plurality of composite material layers are stacked to form a
laminate. Each of the layers may be similar or may differ with respect to one
or more of the included materials and/or properties. During the fabrication of
the laminate, plies of unidirectional tape or fabric plies may be selectively
oriented in the direction that provides the cured product with the properties
desired. The layers may be of similar size and shape and be stacked one on
top of another, or may be of different size and shape. In addition, the
stacking
of the layers may be performed by using a plurality of pieces of composite
material for a layer, or using only a single piece for a layer. The layers of
composite material can be of any suitable thickness or thicknesses.
One way to form a laminate is to roll composite material around
a mandrel having the desired shape of the finished shaft. In accordance with
a preferred aspect of the present invention, the laminate can be formed by
rolling composite material around the mandrel numerous times.
In general, however, the laminate can be formed in any suitable
manner, and those of skill in the art are familiar with many such ways. For
instance, it is possible to form a laminate by wrapping individual layers of
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composite material around a mandrel, wherein each layer is long enough to
wrap around the mandrel at least one time, whereby the layer is placed on the
mandrel with a top edge of the layer in contact with the mandrel or the
outermost layer of composite material already on the mandrel, and the
mandrel is then rotated until the composite material is completely wrapped
around the structure, with the top egde and the bottom edge of the composite
material forming a seam or seams. In the case where the composite layer is
just long enough to make one revolution around the structure, a seam is
formed between the top edge and the bottom edge of the composite layer. It
to is preferable to arrange the layers such that seams are not positioned
above
one another, i.e., after applying one layer, the mandrel is rotated, e.g., 180
degrees, before applying the next layer. However, in general, many different
ways of applying layers of composite to form a laminate are known to those
skilled in the art, and all are encompassed in the present invention.
The composite material in the laminate is brought into contact
with a surface of the metallic tip. In the case where composite material is
wound numerous times around a mandrel, this step can be accomplished by
placing the metallic tip on the mandrel in its desired position relative to
the
composite material (1 ) prior to winding the composite material around the
2 o mandrel or (2) after winding a part of the composite around the mandrel
(and
before winding all of the composite material around the mandrel). In such a
way, the composite material can be wrapped directly around the metallic tip
(e.g., as shown in Fig. 2), or it can sandwich the metallic tip.
Fig. 1 shows a shaft including a laminate 10 and a metallic tip
2s 11. In Fig. 1, the laminate 10 and the metallic tip 11 have axes which
together
form a substantially straight line, this relationship being referred to herein
as
coaxial. The metallic tip preferably has an outer periphery which is similar
to
the outer periphery of the laminate. The metallic tip can be formed of any
suitable metal, with a preferred example being aluminum due to its low density
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{it is desirable to minimize the weight of hockey sticks). Other suitable
metals
include, e.g., titanium, steel alloys, and other metals which provide desired
weight, mechanical properties and appearance.
The metallic tip may have a shape which facilitates attachment
s to the laminate, e.g., the metallic tip may have a stepped portion as shown
in
Fig. 2. In Fig. 2, the metallic tip has a first tip portion 22 and a second
tip
portion 23, the first and second tip portions being integral with each other,
the
second tip portion 23 having an outer surface 24 which is in contact with a
part
of the interior surface of the laminate, and the first tip portion 22 having a
first
1 o tip surface 25 in contact with a transverse edge 26 of the laminate. The
first
tip surface can be oriented at any angle--in Fig. 2, the first tip surface 25
is
shown substantially perpendicular to the longitudinal axis of the metallic tip
21
and the laminate 20. The metallic section may have a recessed or tapered
region to facilitate the placement of polymeric materials and to minimize
1s increased wall thicknesses or buildup. The composite material can be placed
on either or both surfaces of the metallic tip to improve adhesion. Fig. 2
illustrates the composite material being added to the outside surfaces only.
In accordance with the first aspect of the present invention, the
composite layer laminate and the metallic tip are co-cured, by curing the
resin
2 o while the laminate and metallic tip are in contact. Prior to curing, the
assembly
can be wrapped with generic release coat film, if desired. In such a case,
after
the laminate is wrapped and placed into a vacuum bag, the bag is closed and
pressure is applied to the vacuum bag such that the composite conforms to
the shape of the layup mandrel, thereby forming a shaped laminate. The
25 shaped laminate is the shape of the finished hockey stick shaft.
Curing is typically accomplished by heating. The curing can be
conducted by placing the laminate and the metallic tip in a vacuum bag. The
appropriate time, temperature, and pressure required to cure the resin, and
thus co-consolidate the laminate and the metallic tip together depends on the
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nature of the resin, it being well known that different resins cure at
different
temperatures and pressures. Where curing is conducted in a vacuum bag,
after curing, the hockey stick shaft is removed from the vacuum bag.
The metallic tip feature eliminates the possibility of thermally
s induced shaft damage when excessive or prolonged heat is applied to the
forward blade area of the hockey stick shaft. The metallic tip provides
rigidity
and functions as a protective heat shield, in that it dissipates the heat
energy
from an open flame or heat source. Any metallic material can be used, but
because of its lighter density, aluminum alloy is preferred to minimize an
1 o increase in shaft weight.
It has also been found, in accordance with the present invention,
that a metalized polymeric film, or a high heat resistant (>350°F)
polymeric film
could also be used to provide thermal protection to the forward blade area of
the shaft. In this case, the heat resistant film is either secondarily bonded
or
15 co-cured to the outer surface of composite shaft.
In accordance with the second aspect of the present invention,
the laminate and the metallic tip are attached to each other by any suitable
means. For example, the laminate and the metallic tip may be attached by
adhesive bonding or by the use of mechanical fasteners. The metallic tip may
2 o have a stepped portion as described above and as exemplified in Fig. 2.
Alternatively, the metallic tip may be tapered. Adhesive bonding can be
accomplished by applying the adhesive to the surfaces) of the laminate
and/or the metallic tip which come into contact, and curing the adhesive,
e.g.,
by applying heat and pressure, to produce a one-piece, integrated shaft.
2 s Mechanical fastening can be accomplished using rivets, screws, bolts, etc,
to
attach the laminate and the metallic tip.
In accordance with the third aspect of the present invention, a
laminate is formed which comprises a plurality of layArs of composite material
and at least one metallic layer to provide a hybrid layered composite (HLC).
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Each of the layers of composite material can be made as described above
with respect to the first and second aspects of the present invention.
The metallic layer can be made of any suitable material, e.g., the
materials described above for use in making the metallic tip. The metallic
layer can also be made from metallized films.
The laminate in accordance with the third aspect of the present
invention can be made by a process which is similar to the lamination
techniques described above with respect to the first and second aspects of the
invention. During the process of making the laminate, at least one metallic
layer is incorporated into the laminate. The metallic layer can be placed on
the bottom {so that it will form the inner surface of the hollow article), in
between composite layers, or on the top (so it will form the outer surface of
the
hollow article). In Fig. 4, the metallic layer 41 is the second layer from the
top
of the laminate. Optionally, the metallic layer may be combined with a
transparent outer ply, thereby providing a unique metallic appearance to the
composite shaft. The metallic layer is preferably of a thickness in the range
of from about 0.001 to about 0.01 inches.
The laminate is then cured, thereby bonding the plurality of
composite layers and the one or more metallic layer to each other. This step
2 o can be conducted in any manner as described above with respect to the
first
and second aspects of the present invention.
Similar to other composite shafts, the mechanical functionality
of the HLC shaft is affected by the selection of the fiber reinforced
polymeric
prepreg, its gauge thickness, and the orientation of the plies. The HLC shaft
is unique in that the co-consolidation of at least one metallic layer
increases
the thermal protection, toughness and impact damage resistance without
compromising on overall strength and stiffness of the shaft. The co-
consolidation technique also minimizes the potential increase in cost and
weight, by eliminating secondary bonding operations that need adhesive
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materials to attach the metallic layer to the precured composite shaft.
In making a completed hockey stick, a stick blade is attached to
a hockey stick shaft in accordance with the present invention by any suitable
means for attachment, e.g, by adhesively bonding the blade to the shaft, or by
5 mechanically attaching the blade and the shaft. It is also possible to co-
cure
a blade when curing or co-curing the materials in the shaft.
Fig. 5 shows a conventional hockey stick, including a hockey
stick shaft 51 having a blade end 52, and a blade 53 attached to the shaft 51
at the blade end 52 of the shaft.
1 o The shape of the shaft can be any desired shape, such as
rectangular, elliptical, oval, rectangular, etc. and may have rounded corners.
The external dimensions of the handle portion can be made to any desirable
size. The particular size and shape will depend primarily upon the desire of
the user.
The hollow shaft of the hockey stick shaft may be filled with
foam, such as honeycomb reinforcement fillers, closed cell high variable
density foam, or other dampening or strengthening materials in order to alter
the characteristics of the hockey stick shaft.
The present invention makes it possible to take advantage of the
2 o inherent property of metallic materials to resist elevated temperatures
(e.g.,
>250°F) without permanent deformation, and the anti-isotropic design
flexibility of composite materials; it has been found, in accordance with the
present invention, that a high performance, functional hockey shaft can be
manufactured with both of these dissimilar materials.
2 5 The co-consolidation of a metallic alloy tip section to the blade
end of a composite shaft according to the present invention provides thermal
protection to the shaft when heat is used to attach or adhesively bond the
blade to the stick.
The present invention may be embodied in other specific forms
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without departing from the spirit or essential characteristics thereof. The
presently disclosed embodiments are therefore to be considered in all
respects as illustrative and not restrictive, the scope of the invention being
indicated by the appended claims, rather than the foregoing description, and
all changes which come within the meaning and range of equivalency of the
claims are, therefore, to be embraced therein.
