FI72429B - FOERFARANDE FOER FRAMSTAELLNING AV SKAFT FOER ISHOCKEYKLUBBA. - Google Patents

Description

1 72429

A method of making a hockey stick shaft.

For the purposes of this Regulation, this Directive applies to the hockey club.

Today, the stems of hockey sticks are made almost exclusively of wood by gluing and squeezing the wooden slats together. However, there are several disadvantages associated with tree stems. The arms break and hide easily, so large numbers of rackets have to be made and large numbers of spare rackets have to be carried on game trips. Another disadvantage is that due to the inhomogeneity of the wood material, gluing, etc. due to material and manufacturing technical aspects, the rackets are always different, especially their stiffness varies. This disadvantage is exacerbated during the use of the rackets, as critical stress points are triggered inside the racket in stressful situations, making the racket constantly more flexible. This variation in the stiffness of the rackets causes a certain stroke inaccuracy. In addition, the elastic properties of the wood are poor, i.e. the characteristic damping of the wood is relatively high, whereby the elastic energy associated with the straightening of the bending arm in connection with the impact on the disc is poorly recovered to give a higher output speed. The third drawback is the relatively high weight of the wooden racket, since the material in the middle of the closed racket is essentially unnecessary in terms of strength. For technical reasons, the stem is even throughout its length. It follows that the stem most often breaks at the base below the lower arm.

The natural cross-sectional shape of a press product glued from wooden slats is rectangular. The corners of the rectangle have been removed due to a safety risk. However, the structure of the shaft is still angular and in practice it has been found that it still poses a significant safety risk. It has happened, for example, that a finger squeezing an arm has broken against the corner of the arm in a strong flattening.

In order to eliminate the above-mentioned drawbacks, it has long been known to manufacture hockey stick stems from layers of reinforcing fibers, the fibers and layers of which are bonded together with a curable mass. The manufacturing is done by hand-laminating ____ - ττ—: ..

2,72429 tin, which is often accompanied by the production lamination of the shank part and the shoulder part at least in part at the same manufacturing stage, whereby they are joined together. The manufacture of a hollow reinforced plastic arm separately from the blade part is known, for example, from Canadian Patent Publication No. 1,069,147. The arm is made as a handcrafted lamination from strips of fiberglass braid reinforced with so-called "Roving" yarns.

In order to increase the strength of the hockey stick shaft, it has also been previously proposed (U.S. Pat. No. 3,561,760) that the shaft be made of fiberglass-reinforced plastic. The core part of the shaft consists of foam, on which the glass-fiber-reinforced plastic is laminated. For manufacturing reasons, the foam inside the shaft is required to form a core on which a fiberglass-reinforced plastic shell is formed. However, the foam core increases the weight of the shaft without having a significant effect on the strength of the shaft. Such an arm cannot be manufactured by the fractional method, but is made by hand. For this reason, the proposed hockey stick becomes so expensive that it is not competitive with wooden rackets.

U.S. Pat. No. 3,489,412 discloses a method of the type mentioned at the beginning for obtaining a hollow, non-circular, fiber-reinforced thermosetting arm.

The shaft is shown to be made by winding reinforcing fibers around a gradually decreasing cross-sectional core, which are wetted with a binder after winding, e.g. Also in this case, the one-time manufacturing method is artisanal and slow. For this reason, the method is not competitive, even if it could produce stems with better technical properties than wooden stems. On the other hand, the limitation of the manufacture to the use of wound fibers does not allow the most advantageous fiber layer structure in terms of arm strength.

3,72429

On the other hand, it is known, for example, to manufacture a golf club arm, a ski pole or a fishing rod by a continuous process by placing longitudinal and transverse fibers on successively placed cores (e.g. FI publication 55612 and U.S. patent 4,157,181). The method according to the invention uses this known method for producing a hockey stick shaft.

The invention relates to a method for manufacturing a hockey stick shaft by depositing reinforcing fibers around a flat-core core with a box cross-section, so that the cores are conveyed in succession and the I am removed from inside the tubes and fed back to the manufacturing machine.

In order for this method to be suitable for making a hockey stick arm so that a separately manufactured arm can be attached to the blade portion of the racket, metal cores of substantially uniform length with one end flattened like a chisel tip are used for most of the length. In this case, a suitable connecting opening is formed at the end of the arm, around which more transverse fibers can be wrapped around the outer surface of the arm in order to increase the joint strength.

The arm according to the invention can be made sufficiently strong while being lighter than previous arms. Thanks to the mechanical manufacturing method, it is possible to produce stems with exactly the same stiffness, which also retain their rigidity in use, i.e. no fatigue characteristic of tree stems occurs. With such an arm, the player learns the firing accuracy better.

The invention will now be illustrated with reference to the accompanying drawings, in which Figure 1 shows a side view of a hockey stick and Figure 72429 shows a cross-section of a club arm in the case of a preferred embodiment of the invention.

Figure 3 shows, from two sides and at the end, a core from which a stem is made on top of a series of cores.

In the cross-section according to Figure 2, the innermost layer has longitudinal glass fibers in the shaft. On top of this is a cross-wound transverse glass fiber layer. A layer of longitudinal glass fibers has been drawn on it again. The fourth layer from the inside is again a transversely wound glass fiber layer and the outer layer is a longitudinal glass fiber layer. Tape can also be wrapped around the surface of the shaft.

The fabrication of the shaft is carried out by a continuous method in which cores with a flat cross-section, e.g. according to Fig. 3, are transported successively at a small distance from each other. Longitudinal and transverse fiber layers are deposited on top of the cores in turn. The longitudinal fibers are passed through guides, by means of which the distribution of the longitudinal fibers in the different parts of the cross section is desired. To increase the bending stiffness, more longitudinal fibers are guided to the wide sides of the shaft.

The amount of transverse fibers to be wound is controlled by programmable logic so that the desired amount of transverse fibers is obtained at different points along the length of the arm. Especially at the base of the shaft, below the lower arm, more transverse fiber can be wound.

For each longitudinal fiber layer and transverse fiber layer, there are separate successive fiber feed stations in which the resin-wetted fibers are passed around the core.

In order to make the base end of the shank flat for connection to the shank 5 72429, the other end of the core is flattened as shown in Fig. 3 like the tip of a chisel.

Once all the fibrous layers have been formed on the moving core array and the binder has cured by heat catalysis, the tube is cut at the points between the cores, the cores are removed from inside the tubes, and fed back to the machine.

In the case of Figure 2, the shape of the outer surface of the core would have been oval. However, from the point of view of core control, the flat polygonal shape according to Fig. 3 is more advantageous. Also in this case, the outer surface of the shaft is made completely oval by suitable control of the distribution of the longitudinal fibers.

Continuous manufacturing requires a large number of cores and must withstand repeated reuse. For this reason, among others, metal cores are used in the invention.