Note: Descriptions are shown in the official language in which they were submitted.
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Handle shaft for a hockey stick and method and tool for
fabrication thereof.
The present invention relates to a hockey stick han~le shaft,
in which is used a fiber-reinforced thermosetting plastic and
whose cross-section is other than circular. The reinforcement
used is preferably glass or carbon fiber. The invention also
relates to a method for continuous fabricaiion of a hockey stick
shaft from a fiber-reinforced thermosetting plastic. The invent-
ion also relates to a tool for embodying the method.
At present, the hockey stick shafts are constructed almost
exclusively of wood by gluing and pressing wood slivers
together. However, wooden handle shafts are hampered by several
drawbacks. The shafts fracture and break easily which is why
hockey sticks must be fabricated in large quantities and it is
also necessary to carry large quantities of spare sticks on match
tours. Another drawback is that, due to the inhomogeneity, glue-
ing~and other such material and manufacturing factors of wood
material, the sticks are always different from each other,
especially for their stiffness. This drawback deteriorates
during the use of hockey sticks, since in stress situations,
critical bonds inside a stick snap and the stick becomes
. . .
increasingly more resilient. This sti$fness variation of sticks
leads to certain inaccuracy in shots. In addition, the re-
siliency characteristics of wood are poor, i.e. the attenuation
equivalent of wood is relatively high, which means that the
deflection energy,involved in straightening the shaft that bends
in connection with a slapshot directed to the puck,is badly
recovered for a higher initial velocity. A third drawback is
the relatively great weight of a wooden stick since the core
material of a solid hockey stick is essentially unnecessary in
terms of stiffness. For reasons of fabrication technique, a
wooden shaft is of equal material over its entire length. A
result of this is that the shaft most often breaks at its base
portion below the player's lower hand.
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The natural form of cross-section of a laminated product
glued of wood slivers is a rectangle. The corners of said
rectangle are removed because of safety hazard. However, the
design of a shaft is stil1 angul.ar which in practice has
still been found to be a substantial safety hazard. For ex-
ample, there have been incidents that a finger squeezing the
shaft has broken against a shaft corner in a hard stress.
There is a prior proposa]. for the increased strength of a
hockey stick handl.e shaft (US Patent 3 561 760) that the
shaft be constructed of fiberglass-reinforced pl.atics. The
core portion of a shaft is comprised of foam plastic upon
which is laminated said fiberglass-reinforced plastic. The
foam plastic inside the shaft has been required for reasons
of fabrication technique to provide a core upon which a
fiberglass-reinforced plastic sheeting is formed. Neverthe-
less, the foam plastic core increases the weight of a shaft
without any substantial. contribution to its strength. Such a
shaft cannot be fabricated by a continuous process but
production is mostly manual. This is why the proposed hockey
stick will be too expensive to be competitive with sticks
fitted with a wooden shaft.
An object of the invention is to provide a handle shaft for a
hockey stick constructed of a fiber-reinforced plastic and
producible in continuous process by means of an automatic
machine, the price of a shaft becoming approximatel.y the same
as that of a wooden shaft while gaining the above-mentioned
advantages over a wooden shaft.
In order to achieve this object, the hockey stick shaft
according to the invention comprises a hollow tube, including
partly longitudinal and partl.y transverse fibers wound
therearound. Such a shaft can be manufactured by a continuous
process in a manner that successivel.y conveyed mandrels of
rather flat cross-section are laminated by alternately
winding longitudinal. and crosswise fiber layers therearound,
that after setting of a binder the obtained tube is cut to
].engths between said mandrel.s and the mandrels are removed
from inside the tubes and re-fed into
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the production machine.
The tool employed comprises a metal~rel of rather flat cross-
section whose one end is flattened the same way as the tip of a
chisel. Thus, the base of a shaft will be accordingly flat for
fastening it to the blade.
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The flexural rigidity of a shaft is accomp~i3cd mainly by means
of longitudinal fibers and the impact strength and resistance
to buckling are mainly achieved by means of cross-fibers.
An essential aspect in the construction of the invention and its
fabrication is a possibility of selecting the fiber distribut-
ion in an optimum manner in terms of strength.
In order to increase the flexural rigidity without the increase
in weight,the invention suggests that the distribution of long-
itudinal fibers in various parts of cross-section be varied in
a manner that most longitudinal fibers lie on those opposite sides
whose relative distance across the central axis of a shaft is
the shortest.
Also the number of cross-fibers per~lenath un~t of a shaft can be
varied by controlling the number of wound cross-Eibers
by means of a~programmable logic. Thus, the base portion of a
shaft below the player's lower hand can be provided with more
cross-fiber wound therearound.
In terms of the optimization of strength, it is essential that
the number of longitudinal fibers is substantially more than
that of cross-fibers. Cross-flbers are interposed between the
longitudinal fiber layers.
A hockey stick shaft of the invention offers the following ad-
vantages.
A shaft stronger than those of wooden sticks will be more econom-
ic since the number of shafts broken is less than before.
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The shaft can be made sufficiently strong and at the same
time it is lighter than the prior art shafts.
The fiber-reinforced plastic shaft construction returns the
deflection energy better, so the puck will acquire a higher
initial velocity at the same force.
It is a]so possible to manufacture shafts of exactly equal
stiffness which also retain their stiffness in use, i.e. the
fatigue inherent of wooden shafts will not occur. With such a
shaft, the player learns better shooting accuracy.
The cross-section of a hockey stick can be made oval,
contributing on one hand to a grip ( the stick does not turn
in the hands) and, on the other hand, hazardous corners are
eliminated, so the shaft is safer to its users.
The invention will now be described in more detail with
reference made to the accompanying drawings, in which:
FIG. 1 shows a hockey stick in side view and
FIG. 2 is a cross-section of a stick shaft in one preferred
embodiment of the invention.
FIG. 3 is a double side and end view of mandrel upon which
the shaft is fabricated.
The innermost layer 1 in the cross-section shown in Fig. 2
comprises glass fibers extending longitudinally of a shaft. A
crosswise fiberglass layer 2 is wound therearound. Upon the
latter there is another layer 3 of longitudinal glass fibers.
A fourth layer 4 counting from inside comprises again a
crosswise wound fiberglass layer and the outermost layer 5 is
a longitudinal fiberglass layer. A tape can still be wound
around the surface of a shaft.
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The shaft fabrication is effected by a continuous process,
wherein rather flat cross-sectioned mandrels~shown e.g. in fig.
3, are conveyed successively,spaced a small distance from each
other. Longitudinal and crosswise fiber layers are laminated
alternately upon said mandrels. Longitudinal fibers are passed
through fairleads by means of which the longitudinal fiber
distribution in various parts of cross-sectio~ is obtained
as desired. For increased flexural rigidity, the broad sides of
a shaft are provided with more longitudinal fibers.
The number of cross-fibers to be wound is controlled by means of
a logic in a manner to provide a desired amount of cross-fiber
in various sections of the shaft length. It is particularly
plausible to wind more cross-fiber on the base portion of a shaft,
below the player's lower hand.
For each longitudinal fiber layer and cross-fiber layer are
provided successive fiber supply stations, wherein the resin-
moistened fibers are passed around a mandrel.
In order to make the base of a shaft flat for attachment to the
blade, one end of a mandrel is flattened the same way as the tip
of a chisel, as shown in fig. 3.
When all fiber layers have been fabricated upon a moving array of
mandrels and when a binder has set as catalyzed by heat, the
tube is cut to lengths at points between said mandrels, the latter
are removed from inside the tubes and re-fed into the machine.
In the case shown in fig. 2, the external shape of a mandrel
would have been oval. However, in terms of steering a mandrel,
the rather flat polygonal shape is preferred. Even in this case,
the outer surface of a shaft can be made completely oval by
properly controlling the distribution of longitudinal fibers.
In continuous fabrication, the mandrels are required in large
quantities and they must withstand successive re-runs. This is
one of the reasons why metal mandrels are employed in the invention.
