Note: Descriptions are shown in the official language in which they were submitted.
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SINGLE PIECE HOCKEY STICK ]BI~DE UNIT AND ME'I'HOD
BACKGROUND OF THE INVENTION
Field of the Invention
This invention rela$es to hockey stick bladesa and in particular to hockey stickblade units of synthetic materials which are adapted to be replaceably affixed onto
a shaft to form the entire stick.
Description of Related Art
Conventionally hockey sticks have been made of wood with the blade of the
stick being affixed to the shaft by a rabbet joint and an adhesive. It is well recognized
by hockey players that such conventional sticks frequently have a short life span even
if the blade is protected by tape. It is difficult to obtain wood of sufficiently high
quality and even that is subject to considerable variation in strength. Even the best
wood in hockey sticks breaks in use, particularly when subjected to the extreme forces
encountered during professional league play. Furthermore, it is difficult to give
wooden hockey sticks the exact characteristics desired by professional players. As a
result of both of these factors, there has been a tendency to move towards non-
wooden stick3.
For example, United States Patent No. 3, 934, 875 Easton et al. discloses a
fiber filled plastic blade. The blade is mounted on an alurminum alloy tube which
attaches to ~he shaft or handle. The mounting of the reinforced plastic blade on the
shaft is accornplished by means of a separate aluminum alloy shank. The shank has
a tapered lower portion which is embedded into a vertical extension of the blade.
The upper portion of the shank is rectangular is section and fits within a rectangular
socket at the bottom of the shaft.
However, this hockey blade suffers a number of potential drawbacks. For one
thing, the blade is heavier than desirable because of the metal shank and the weight
of the blade itself which is made of glass fiber reinforced plastic. Second, the blade
is prone to damage due to separation of the shank from the rest of the blade andseparation between the shank and the shaft which are connected by an adhesive.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an improved blade unit for a hockey
stick which is lighter in weight than prior blade units but retains the necessary
5 strength.
It is another object of the invention to provide an improved hockey stick blade
unit which is more durable in play than previous blade units.
It is a further object of the invention to provide an improved hockey stick
blade unit which is economical to produce and market.
It is a still a further object of the invention to provide an improved method ofconnecting hockey stick blade units to shafts so that the two do not separate even
15 under extreme forces encountered during play.
In accordance with these objects, one aspect of the invention provides a
hockey stick blade unit, comprising a single molded plastic member having a top, a
bottom, opposite sides, a shank, a blade having a tip and a rigid synthetic foamed
20 inner core with a synthetic exterior skin extending thereabout. Ihe member has
reinforcing fibers dispersed therethrough. The shank has a shaft receiving portion
adjacent the top of the blade. The shaft receiving portion is rectangular in section.
The shank has a lower portion connected to the blade. The sides of the member
taper inwardly towards the tip of the blade, whereby the member is thinnest adjasent
25 the tip.
:
Another aspect of the invention provides a method of making hockey stick
blade units. The method comprises the injection molding of a single plastic member
having a blade and a shank. Preferably the blade unit is injection molded utilizing
30 an aluminurn mold for example. The mold may be injected with a synthetic having
a foaming agent and fiber reinforcement.
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A still furthcr aspec~ of the invention provides a method of assembling a
hockey stick. The method comprises securing a metal shaft, having a socket at a
bottom ~nd thereof, to a one-piece blade unit having blade and a shank of fiber-reinforced synthetic foam with a synthetic skin extending thereabout. The shaft is
5 secured to the blade unit by heating the bottom end of the shaft to expand thesocket, fitting the socket over the shank, and allowing the bottom end of the shaft to
cool to shrink the recess tightly about the shaft.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
Fig. 1 is a top, side isometric view of a hockey s~ick blade unit according to an
embodiment of the invention;
Fig. 2 is a front elevation thereof;
Fig. 3 is a top plan thereof; and
;
Fig. 4 is a sectional view taken along line 4-4 of Fig. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings, these show a hockey stick blade unit 10 which
25 comprises a single piece molded plastic member 12. The member has a tip 14, a bottonn 16, opposite sides 18 and 20, a shank 22 and a blade 24.
The shank has a shaft receiving portion 26 which is generally rectangular in
scction as seen best in Pig. 3. However, it has four rounded corners as shown, for
30 example, by corner 28. The shaft receiving portion is of substantially constant cross-
section apart from a rounded top 30.
The shank also has a lower portion 32 which is connected to blade 24 and
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merges therewith adjacent bo~tom 34 of the shank. As may be seen best Fig. 2, the
sides 18 and 20 of the member taper towards each other along the lower portion 32
of the shank such that the shank is the thinnest adjacent the bottom 34 and the
thickest at a point 36 below the shaft receiving portion 26. There is a reverse tapered
portion 38 of the shank between the lower portion 32 and the shaft receiving portion
26 which tapers from a larger cross section at point 36 adjacent the lower portion to
a smaller cross section at a point 40 adjacent the shaft receiving portion 26.
As may be seen best in Fig. 1 and 3, the tapering of member 12 continues
along the blade 24 towards the tip 14 such that the member is the thinnest adjacent
the tip. It may also be seen in this preferred embodiment that the corners of the
member, such as corner 42 extencling along top 44 of the blade and front 46 of thc
shank, are rounded. In general, the shape of the blade and shank up to point 36 are
generally similar to a conventional hockey stick.
The member 12 of this embodiment is a single piece of molded plastic. A
number of synthetic materials could also be used. In this embodiment the material
employed is nylon 6 although nylon 6/6 could also be utilized as could high impact
polyurethane. The synthetic material is reinforced with fibers. ln this particular
example the fibers are a 12.5% graphite/carbon fibers with 37.5% short glass fibers.
The percentages relate to the fiber content of the member by weight. The rest of the
material is nylon or other synthetic. Boron fiber may also be used to supplement or
replace the graphite/carbon fiber. Kevlar may supplement or replace the short glass
fiber.
As seen best in the sectional view of Fig. 4, the synthetic has a foamed core
48 surrounded by a skin 50 which completely surrounds the number 12 to enclose the
foamed core. The skin is of the same synthetic material as the core in this example.
Method of Molding
The member is one step injection molded in this example. The mold is
preferably aluminum instead of the usual steel because of tli~e high heat transfer rate
of aluminum. This allows the mold to be quickly cooled after it is injected with the
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hot synthetic to form the skin 50 discussed above. An end gate is preferably used on
the mold and the material flows towards the tip 14.
The mold is charged with a conventional screw filled with the synthetic
material, such as nylon, in shot form, the reinforcing fibers and a foaming agent. The
foaming agent may be endothermic or exothermic. In this example RTP-BAFCX
26310 is used. Enough foaming agent is used to achieve a density reduction
percentage of approximately 26.5%. In other words, the foamed blade weighs 26.5%less than an unfoamed unit of the same size.
To obtain maximum foaming action, a low profile injection screw is used in
this example. The screw has a length between 1,200mm and 1,500mm. The length
of the screw effects the compression ratios which should not be less than 2:1 and not
more than 4:1. The injection speed is in the medium to fast range. ~-
The size of the shot depends upon the particular molding machine and other
such factors. A closed loop is used for maximum replication. The holding time and
cooling time are normal for this type of component. The profiled barrel temperatures
are important. The heater band temperatures should not be less than 300 F. and
should not exceed 600 F.
Method of Assembly ~ .
The botto~n portion of a shaft 52 is shown in stippled lines in Fig. 2 and 3.
The shaft has a recess 54 formed in the bottom 56 thereof which is adapted to receive
portion 26 of shank 22. The recess 54 is generally similar in shape to portion 26, but
is slightly smaller in cross section. The shaft 52 is fitted onto member 12 by heating
the bottom portion of the shaft adjacent recess 54. The shaft is conventionally of
aluminum and the heating causes the aluminum to expand including recess 54.
Portion 26 of the shank is then inserted into the recess. The shaft is cooled and this
causes the shaft to shrink onto the shank. This forms a permanent and very tightbond. ~Iternatively, the shaft could be connected to the shank by an adhesive. An
adhesive could also be used to supplement the heat shrinking process.
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It will be understood by someone skilled in the art that many of the details
provided above are by way vf example only and are not intended to limit the scope
of the invention which is to be interpreted with reference to the following claims.
