Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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STICK COMPRISING SHAFT AND BLADE
The invention relates to a stick, such as an ice hockey stick, which
comprises a shaft and a blade part and in which the shaft and the blade part
are
separately manufactured and joinable together, an end of the shaft meant for
the
joint being tapered and the blade part comprising a socket arranged to receive
said shaft end.
PRIOR ART
The history of evolution of ice hockey sticks knows at least two peri-
ods of replaceable blades. US Patent 3,638,942 discloses a plastic blade with
a
socket in its shaft area into which a traditional stick shaft is inserted.
This stick
was mainly for small boys and could be conveniently assembled using a wooden
shaft and a plastic blade of a broken stick.
Later, when aluminium and composite shafts became more common, a
replaceable blade, such as the one shown in Fig. 12 of US Patent 5,407,195,
was
created, where the shaft portion of the blade had a jointing shank formed
thereto,
its dimensions corresponding to the inner dimensions of a hollow shaft. Sticks
made with this technique were used even on the pro-level and, at the time,
they
solved a problem related to logistics and quality of service to be discussed
below.
However, the joint was in an area that is technically sensitive as regards
loading
of the stick and, to make it strong, the structure had to be locally
reinforced,
which caused a weight problem in the sticks. Consequently, sticks of this type
have disappeared from the market almost completely and they have been re-
placed by sticks delivered in one piece.
CURRENT PROBLEM
Current ice hockey sticks are commonly carbon fibre composite struc-
ture sticks. They are made either by manufacturing the shaft and the blade to-
gether, in one work phase, or the shaft is made separately and the blade is
then
fixedly fastened to the shaft before finishing of the product. In other words,
the
sticks are marketed as single, non-disassemblable pieces.
A problem with current sticks arises e.g. when a plural number of
shafts of different stiffness, at least 2 to 3 different stiffness classes,
are needed
due to different habits of the players. Moreover, players have personal prefer-
ences regarding blade shape and, naturally, stick handedness. Top brands have
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usually about ten different blade models commercially available. In addition,
tai-
lored blade designs are commonly made for professional hockey players.
The quality of service required by market demands leads to a logistics
problem that is extremely difficult to manage because a standard product range
of
3 shaft stiffness classes and 10 different blade models alone means a range of
30
different product titles, not to mention the service to pro-level players that
may
involve hundreds of different variations.
Today, ice hockey stick manufacturers usually have their production
plants in remote countries of cheap labour, which further complicates the
service
to consumers and the retail trade and makes it more difficult.
SOLUTION TO THE PROBLEM
An ice hockey stick according to invention has a shaft and a blade that
are separately made products. The structure is designed so that the blade may
be
fastened to the shaft simply by instant glue. The fastening may either take
place at
the retailer's store or the player may do it. When both the shaft and the
blade now
have separate product names, the number of product titles in the above-
mentioned standard product range drops from 30 to thirteen, which
significantly
reduces logistics costs and enables a marked improvement in quality of
service.
The stick according to the invention is characterised in that the socket in
the
blade part is formed entirely in the heel part of the blade part and thus the
struc-
ture of the heel part and the socket end at the same level in the direction of
the
shaft.
In the following, the invention will be explained in closer detail with
reference to the accompanying drawing, in which
Figure 1 shows an ice hockey stick with the shaft detached from the
blade part.
Figure 2 shows a goalkeeper's stick with the shaft detached from the
blade part.
Figure 3 shows a cross section of a portion of a blade part.
Figures 4a to 4d show cross sections of a blade part.
Figure 5 shows a portion of a blade part of an ice hockey stick and a
cross section thereof.
Figures 1 and 2 show stick blades 1 and 2 that are manufactured as
separate products. They are joined to shafts 3 by means of a jointing element
pro-
vided by a socket 4 formed to the heel part of the blade part 1, 2 and a taper
at a
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bottom end 5 of the shaft 3 to match the socket 4. The joint is in an area
where
the bending moment of the stick 3 is close to minimum and the joint merely
most-
ly transmits torsional forces from the shaft to the blade part 1, 2. The
bending
moment directed to the shaft 3 is the greatest at the lower support hand grip,
i.e.
approximately in the mid-part of the shaft 3.
Figure 3 shows a blade part 1 with a socket 4 receiving a bottom end 5
of a shaft 3, the socket being complementary in shape to the bottom end 5 of
the
shaft 3. The blade part 1 shown in Figure 3 and the corresponding cross
sections
4a to 4d are made in an injection mould, which has a removable mandrel match-
ing the inner surface of the socket 4 and reinforcing fibres arranged therein.
The
blade portion 1 is formed by wrapping the mandrel and the lightweight core in
a
seamless fibre structure, and this preform is placed in the mould into which
resin
is injected under pressure. The mandrel has been coated with a release agent
al-
lowing it to be withdrawn from the socket 4 once the resin has cured.
Figure 5 shows an upward pointing portion of a blade part 2 of a goal-
keeper's stick, which has a socket 4 for the bottom end 5 of a shaft 3. The
bottom
end 5 of the shaft 3 maintains a constant width along its longer side but
tapers
along its shorter side. The blade part has a core 6 of a light-foam material
or light
wood, for example, which is wrapped in fibre reinforcement.
Making the blade parts 1, 2 and the shafts 3 as separate pieces enables
significant advantages to be gained also in the manufacturing process.
Filament
winding may be applied to the shafts 3 to enable a partly continuous
manufactur-
ing process and use of more economical raw material. In comparison with the
manufacturing of one-piece sticks, separately made blade parts 1, 2 allow
signifi-
cantly more advantageous mould solutions to be obtained. Blade moulds for spe-
cial sticks can be made of cast resins suitable for small series, which
enables to
further improve the service provided to an individual player.
In an embodiment of the invention, at least 75 % of the socket length is
arranged inside the heel part of the blade part 1, the rest of the socket,
i.e. about
25 mm at the most, extending in the direction of the shaft 3.
In another embodiment of the invention, the blade part 1, 2 comprises
a pre-fabricated socket 4 and a plastic core attached in association with it,
with
fibre laminate layers glued under pressure to their surfaces on both sides of
the
blade part 1, 2. The plastic core has a shape corresponding to the light-foam
core
shown in Figures 3 to 5.
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In an embodiment, the blade 1, 2 comprises a socket 4 with thin walls
and a core 6, together with a surface layer 7 formed around the socket 4 and
the
core. The socket 4 may be of a seamless reinforcing material, such as fibre
rein-
forcement. The socket may be formed by means of at least one uniform, seamless
braided layer of fibre reinforcement to be installed around a mandrel. The
fibre
reinforcement layer may be formed by means of a carbon fibre braid, for
example,
or by winding a uniform continuous carbon fibre band around the mandrel. The
core 6 of the blade 1, 2 may be made of light foam, plastic, expanded thermo-
plastic or cast resin lightened with microballoons. The formed core 6 of the
blade
1, 2 and the socket 4 are joined together by coating them with at least one
seam-
less layer of reinforcement fibre. The fibre reinforcement layer may be made
in
the same way as the fibre reinforcement layer of the socket. Next, the preform
of
the blade is placed into a mould, where it is impregnated with resin and cured
under pressure and heat. The surface layer 7 of the blade 1, 2 may comprise
rein-
forcing fibre, such as carbon fibre or a similar fibre reinforcement, and a
bonding
agent, such as epoxy resin. The seamless carbon fibre structure allows the
socket
4 and the blade 1, 2 to be provided with maximum strength.
