FI55612C - sKI STICK - Google Patents

Description

ΓβΊ «« ANNOUNCEMENT rrc1o Jsgfg LBJ (11) UTLÄGGNINGSSKMFT 556 12 patents meddf »lnt ^ ^ (51) Kv.lk. '/ Int.CI.1 A 63 C 11/22 FINLAND — FINLAND <*) Patent application - Patentansökning 750 ^ 08 (22) Hakamltpllvl - Ansekningsdag lH. 02.75 ^ ^ (23) Alkupllvi - Glltlgheudag 1 ^ .02.75 (41) Become public - Bllvlt offmtllg 15.08. j6

Patents · and registries ,,,,. , _. . (44) Date of issue and other date. -

Patent · och registerstyrelsen 'Anaökan utlagd och utl.skrlften pubtlcerad 31.05.79 (32) (33) (31) Privilege requested — Begird priority (71) Exel Oy, Uunisepäntie 7> 00620 Helsinki 62, Finland-Finland (Fl) (72) ) Yrjö Aho, Westend, Finland-Finland (Fl) (7 * 0 Leitzinger Oy (5 * 0 Ski pole - Skidstav

The invention relates to a ski pole consisting of two or more layers of fibers, the fibers of which are bonded together by a curable mass.

In cross-country skiing in particular, the lightness of the pole is essential, as the pole has to be carried in the hand first and accelerated from a speed of 0 to a considerable speed. Thus, the importance of the lightness of the rod is even greater than that of a ski that slides along the piste for most of the journey. Rods that are light in relation to their strength can now be made of, for example, light metal as well as reinforced plastic, which is most commonly known as a combination of glass fiber and enoxy or polyester resin. However, fiber-reinforced rods have so far not achieved decisively better results than metal rods, because the direction, order and the possibility of combining different types of fibers have not been fully exploited. For example, replacing or blending fiberglass with stronger carbon fiber does not in itself produce the expected result.

The object of the invention is to provide a new type of fibrous rod which can be made lighter than the existing rods without suffering from strength and rigidity, and in which the increase in cost compared to a conventional fiberglass rod can be considered reasonable in comparison with the advantages obtained.

This object is achieved by the invention in that one fibrous layer consists of transverse, wound-wound glass fibers of the rod and the other fibrous layer consists of longitudinal carbon fibers of the rod or both carbon and glass fibers, both layers being attached to each other.

Thanks to the light and strong carbon fibers, the rod according to the invention becomes substantially lighter than before.

However, what is essential in the invention is how the method of combining carbon fiber and glass fiber according to the invention provides the desired properties to the rod. As is known, the tensile strength and modulus of elasticity of a carbon fiber are considerably higher than the corresponding values of a glass fiber, so its placement as a longitudinal fiber results in a very strong and rigid rod per se, and a stiffness equivalent to a fiberglass structure is achieved with much less fiber. However, the elastic elongation of the carbon fiber is small, so that the rigid rod breaks with a relatively small deflection, unless the allowable deflection of the rod in the elastic region can be increased in new ways. This is provided by the effect of influencing the ovalization of the cross-section associated with the bending.

Too easy ovaling causes the rod to buckle and break by buckling before the tension in the longitudinal reinforcement has reached the permissible value, so that resistance to the ovalization tendency in the invention by means of transversely wound fibers is necessary. However, an excessively rigid transverse reinforcement results in a sharp rupture event in the rod containing carbon fibers as a longitudinal reinforcement without any significant ovalization. Thus, a carbon fiber with a high modulus of elasticity is unsuitable as a transverse reinforcement, whereas a glass fiber with a lower modulus of elasticity is particularly suitable for this purpose, especially in a rod with carbon fibers as the longitudinal reinforcement. The transversely reinforced glass fiber allows the rod to ovalize to such an extent that an optimized elastic deflection is obtained for the rod without the stress in the longitudinal carbon fibers rising to the breaking point.

55612

In the following, the invention will be described in more detail with reference to the accompanying drawing, in which:

Fig. 1 shows a rod according to a first embodiment of the invention in cross-section and a vertical section, Fig. 2 shows a rod according to a second embodiment of the invention in a cross-section and a vertical section and Fig. 3 shows a rod according to a third embodiment of the invention in a cross-section and a vertical section.

In the embodiment according to Figure 1, the tubular rod consists of an inner fiberglass layer 1 and an outer carbon fiber layer 2. The rod is made in such a way that the core, i.e. the so-called glass fiber strands are wound around the core, either as a flat fiber layer or as a helical fiber bundle, the spaces being filled with resin. In general, the latter option means that, when viewed in vertical section, there are densities and thinnings in the distribution of the glass fibers. In the same manufacturing step, immediately after the winding of the glass fibers, the longitudinal carbon fibers of the rod are drawn. This can be done in a known manner by passing the carbon fibers moistened with the curable mass through an annular, compression nozzle. The carbon fibers can be drawn suitably prestressed and a tape is wound on the rod formed in the next step, which binds and compresses the fibers and the resin together until sufficient curing has taken place to remove the surrounding tape. The production can take place continuously, in which case, after the tape winding step, the formed tube is cut into rods of the desired length and the resin is cured.

In the embodiment according to Fig. 2, the innermost longitudinal carbon fiber layer 2 'is wound and a transverse glass fiber layer 1' is wound on it. A longitudinal fiberglass layer 3 is further drawn on top of this. The location of the longitudinal fiber layers 2 'and 3 and the choice of material and 3.

4,55612

In the embodiment according to Fig. 3, the two inner layers are formed in the same way as the rod according to Fig. 1. In addition, a second transverse glass fiber layer 1 * 'is wound on the carbon fiber layer 2 and a longitudinal glass fiber layer 3 is further drawn thereon. In this embodiment, the buckling of the carbon fiber layer 2 is effectively prevented, so that its high tensile strength can be effectively utilized. Sufficient strength and rigidity of the rod has been achieved with a relatively small amount of carbon fiber and a relatively large amount of cheaper glass fiber has been able to be used. Nevertheless, the rod is substantially lighter compared to known fibrous rods having similar strength and stiffness values. When the longitudinal carbon fiber layer 2 is located closer to the core of the rod than the longitudinal glass fiber layer 3, a more even distribution of stresses between the longitudinal fiber layers is achieved in the same manner as in the embodiment according to Fig. 2.

The invention is, of course, not limited to the above embodiments. Thus, some of the carbon fibers of the longitudinal reinforcement 2, 2 'can be replaced by a cheaper glass fiber, as long as the transverse reinforcement 1, 1' uses only glass fiber. Other types of fiber-layer combinations are also within the scope of the invention and the advantages of the invention are maintained if they include the combination according to claim 1.

Claims (5)

5,55612 Ski pole consisting of two or more layers of fibers, the fibers of which are bonded together by a curable mass, characterized in that the fibrous layer (1, 1 ') consists of transverse, multi-wound glass fibers and a second fibrous layer (2, 2') consists of longitudinal carbon fibers of the rod or of both carbon and glass fibers, the two layers being attached to each other. Ski pole according to Claim 1, characterized in that the inner layer (1) consists of transverse glass fibers and the layer (2) on it consists of longitudinal carbon fibers. Ski pole according to Claim 1 or 2, characterized in that a transverse glass fiber layer (1 ", 1 ') is placed on top of the longitudinal carbon fiber layer (2, 2'). Ski pole according to Claim 1 or 3, characterized in that the inner layer (1, 2 ') consists of longitudinal carbon fibers and is covered with a transverse glass fiber layer (11). Ski pole according to one of the preceding claims, characterized in that the outermost layer is a longitudinal fiberglass layer (3). ✓