Roller ski

Abstract

 Roller ski with a rectangular hollow body (10) with its narrow side downwards, which is mounted via single-sided forks (19) on a forward and a rear wheel (11, 12). The hollow body is so formed and comprises such material that for horizontal forces it has a lateral flexing property which also makes the roller ski suitable for skiing with the so-called ski-skating technique. The upper side of the hollow body is narrow and a foot deck (16,17) is arranged in the immediate vicinity of the rear wheel. The foot deck is divided into a toe portion (16) and a heel portion (17) in order that the lateral flexing properties will not be deteriorated.

Description

Technical Field .

[0001] The present invention relates to a roller ski including a ski body mounted on a forward and a rear wheel, a binding or attachment for a ski shoe (boot) being arranged between the wheels.

Background Art

[0002] In skiing today, apart from the conventional poling and diagonal skiing, there is used to an ever- increasing extent so-called "ski-skating". This is reminiscent to a high degree of ordinary ice skating, and is either done by toeing out with the ski tips, so-called "herringboning", this technique mostly being used heretofore on upward slopes, or by towing out with one ski only, resulting in that the other ski (hereinafter designated the "track ski") is kept in the track, the other ski (hereinafter designated "the skate ski") being toed out sideways, this manner of skiing being the one most prevalent of the two, and allowing the maintenance of greater speed with less effort than customary poling or diagonal skiing. This kind of skiing is most often done without so-called ground wax which also contributes to the ski working more lightly and quickly.

[0003] In snow skiing using single-sided towing out of one ski, the track ski is down in the track or rut formed by earlier skiing and the transverse forces acting on the ski and urging it out transversely are entirely taken up by the edges of the rut.

[0004] In a corresponding manner of skiing with roller skis, the track ski is also affected by transverse forces steering it outwards, and it must be returned to the travelling direction using a technique not found in the present snow skiing technique.

[0005] In snow skiing with toeing out of one ski, the foot on the skate ski is put down as near as possible to the heel on the track ski, the skate ski then crossing over the track ski, which is possible since the track ski is down in the rut at a depth which is greater than the height of the ski.

[0006] With roller skis this crossover is impossible, and the difference between snow skiing will be greater the more the track ski is extended behind the shoe heel and the wider the skate ski is, due, for example, to the fact that the fork halves of the roller mountings on both sides of the roller must be added to the width of the roller.

[0007] In skiing with snow skis, customary in the technique in question, the skate ski base is angled to a considerable degree. If known roller skis are angled to the same amount, the roller fork mountings scrape against the ground, which means that the skier cannot train technically correctly and also that the fork mounting can dig into the ground and cause abrupt stoppage with a fall and a risk of injury.

[0008] It is attempted today, by such as the selection of materials, to make the snow skis in question as light as possible.

[0009] The roller skis of today are dimensioned to completely take up both vertical and horizontal forces so that, for example, the positions of the wheels in the travelling direction will not be changed. They are also implemented with a roll-back stop unnecessary for "ski-skating" involving that wheel hub and shaft are made in strong steel. Altogether this makes the roller ski used at present about 3 times as heavy as the appropriate completition snow ski of today.

Disclosure of Invention

[0010] The object of the present invention is therefore to solve the above-mentioned problem in the difference between skiing on snow skis and skiing with roller skis, and particularly with reference to ski skating.

[0011] This is achieved by the ski body being made of a hollow section having upper and lower walls of a shape narrower than a normal ski shoe, the upper wall having a foot deck formed integrally with the wall close to the rear wheel.

[0012] By shaping the hollow section with a rectangular cross section with its short side downwards, the ski body will be laterally flexible for the skiing load. At the same time it supports a fork mounting for the forward and rear wheels.

[0013] That the track ski in roller skiing tends to diverge is thus prevented by the carrying member being so slender in relation to horizontal forces that it flexes, the wheels then changing their attitude in relation to the straight line so that the roller ski steers inwards towards the direction from which the horizontal force comes. When the roller ski is not actuated on by horizontal forces it remains straight, of course, and goes straight forwards like other known roller skis.

[0014] Since the carrying member is implemented such as to take up vertical forces to a greater extent than horizontal forces, it is suitable to use for it a rectangular hollow section with its short side downwards.

[0015] To prevent that the foot deck will not reinforce the carrying member and prevent its lateral deflection properties it is suitable to make cutouts in the areas of the deck not required for its intended purpose, thus solely forming a toe portion and a heel portion.

[0016] So that the skate ski may have its base tilted at a large angle to the horizontal and to enable it to be put down as near the shoe, heel on the track ski as possible, the inventive roller ski has been formed with only a half fork mounting for each of the forward and rear wheels. In accordance with the invention the fork mountings of the roller ski are formed by the hollow section itself.

[0017] The lightness of the ski is enabled by using less material, since it does not need to be dimensioned for being straight when it takes up horizontal forces, and is intended to be laterally flexible, as well as not being provided in a basic embodiment with a roll-back stop not necessary for skate skiing. The wheel hub can then be made in such as aluminium or plastics material. The wheel shaft can be implemented in lighter material, e.g. with a steel core for carrying and assembly.

Preferred Embodiments

[0018] The present invention will now be described in detail below in connection with the preferred embodiments illustrated on the accompanying drawings, where

Figures 1 and 2 illustrate known skiing technique using ordinary skis on snow,

Figures 3 and 4 illustrate the same skiing technique using known roller skis,

Figures 5 - 7 again show the same skiing technique, but now using roller skis in accordance with the present invention,

Figures 8 and 9 illustrate in more detail what is characteristic for this skiing technique, on snow with oridnary skis and also on the ground using roller skis,

Figure 10 is a side view of a first embodiment of the inventive roller ski,

Figures 11 and 12 illustrate the roller ski according to Figure 10 seen from above,

Figure 13 illustrates a second embodiment of the inventive roller ski seen from above,

Figures 14 - 16 are sections A, B and C according to Figures 10 and 13,

Figure 17 is a detail of a preferred embodiment of the journalling shaft for the roller ski in accordance with the invention and

Figure 18 is a preferred embodiment of a wheel for the inventive roller ski.

[0019] When skiing on snow the skiers have more and more embraced a skiing style similar to ordinary ice- skating. This can be executed as one-sided toeing-out of the ski tip or toeing-out both skis. Figures 1 and 2 illustrate one-sided toeing-out on snow with ordinary skis, one ski, the track ski 1, following the track or rut 2 in the snow. The other ski, the skate ski 3, is put down behind the skier in ski-skating so that it crosses over the other ski, as will be seen from Figure 1. In Figure 8 it will be seen how this crossing of the skis 1 and 3 is possible when skiing on snow, due to the track ski 1 lying deep in the rut 2.

[0020] If this skiing style is transferred to roller skis of the kind known up to now, the situation illustrated in Figures 3 and 4 is obtained. Since known roller skis are relatively long, i.e. the binding is arranged at a good distance from the rear wheels, the skate ski 3 cannot be made to cross the "track" of the track ski 1, which is illustrated in Pigure 3. Furthermore, known roller skis are so implemented that if the ski skating technique is used, the track ski 1 diverges from the track and forms an angle oc to the travelling direction 2' in a manner illustrated in Figure 4, and must be returned to the track by the skier. This return movement or force has no correspondence in the relevant snow skiing technique.

[0021] With roller skis implemented in accordance with the present invention, there is however obtained an action entirely corresponding to that carried out in the relevant snow skiing technique. The roller ski in accordance with the present invention, as will be more closely described in conjunction with Figures 10 - 13, is short and it has the binding or foot deck arranged in the immediate vicinity of the rear wheel. The roller skier can thus train and ski in exactly the same way as is applicable to skiing on snow, as will be noted by comparing Figures 5 and 7 with Figures 1 and 2. It will thus be seen from Figure 5 that the skate ski 3 can be moved crosswise behind the track ski 1, the travelling movement and the application of effort corresponding to what is applicable with the crossing ski movement according to Figure 1. This is also apparent from the comparison of Figure 9 with Figure 8.

[0022] The reason that the track ski 1 during skiing on roller skis in accordance with the present invention follows the direction of travel 2' without the skier needing to take any corrective movements is primarily due to the lateral flexibility of the ski, as is exaggeratedly indicated in Figure 6. The roller skis in accordance with the invention are namely formed to be laterally flexible. Another reason for the tracking property may be attributed to the journalling of the wheel and the implementation of the wheel.

[0023] In Figures 10 - 12, 14 and 15 there is illustrated a first embodiment of the roller ski in accordance with the present invention. The roller ski includes a ski body 10 mounted on a forward wheel 11 and a rear wheel 12. The ski body 10 comprises a hollow body with a rectangular cross section with its short side downwards, as will be seen from Figure 14. The hollow body thus has side walls 13 of greater extension than its upper and bottom walls 14, 15. With this hollow body shape and a well suited thickness for the selected material, which is suitably of the lightweight type such as aluminium or plastics (optionally reinforced plastics), a lateral flexing ability well balanced to the forces acting on the ski body 10 is obtained when skiing.

[0024] In this embodiment of the roller ski in accordance with the invention, the upper wall 14 of the hollow body is formed with a foot deck 16, 17. The foot deck 16, 17 is centered about the longitudinal axis 20 of the ski body 10, and has fastenings 18 for bindings for the ski shoe (not shown). The foot deck 16, 17 is arranged in the immediate vicinity of the rear wheel 12 and is further divided into a toe portion 16 and a heel portion 17, substantially for reducing the weight of the roller ski, but also so as not to constitute an obstacle to the above-mentioned lateral flexing ability.

[0025] The wheels 11, 12 are suspended by each a one-sided fork 19 being formed by the hollow body. In the embodiment illustrated in Figures 10 - 12 of the roller ski, the hollow body is joggled so that the forks 19 are parallel to the rest of the hollow body. The central axis of the wheels, which is at right angles to their axes of rotation, is thus in register with the longitudinal axis 20 of the ski body 10.

[0026] A second embodiment of the roller ski in accordance with the present invention is illustrated in Figures 13, 14 and 16. Elements which are the same as in the above-described first embodiment have been given the same reference numerals. The illustrated second embodiment of the roller ski in accordance with the invention has a foot deck 16', 17' starting from the upper wall 14 of the hollow body in only one direction as will be seen from Figure 16. The foot deck 16', 17', which is similarly divided into a toe portion 16' and a heel portion 17', thus has its longitudinal axis displaced parallel relative the longitudinal axis of the ski body in a direction towards the roller ski lying at its side in a roller ski pair.

[0027] With this arrangement of the foot deck 16', 17', the wheels 11, 12, the central axes of which are to be in register with the longitudinal axes of the foot deck 16', 17', are mounted in forks 19' which are parts of the hollow body, without the later needing to be joggled. There is thus obtained a completely straight ski body 10, 19'.

[0028] Returning to Figure 12, it will be seen that this figure illustrates to an exaggerated scale how the track ski 1 (Fig. 6) flexes laterally under the action of the horizontal forces P occurring during skiing, thus causing the track ski to go straight.

[0029] An essential part of the invention for this maintenance of tracking would also be the suspension of the wheels "1, 12 in the extensions 19, 19' of the hollow body, these extensions having been termed fork mountings hereinbefore. Figure 17 illustrates the wheel shaft 21 made in a light material such as plastics or aluminium with a core 22, e.g. of steel. The core 22 has the form of a screw or bolt which consists of, or reinforces the carrying properties of the wheel shaft 21 as well as fastening it to the ski body 10. Through holes 33 have thus been made in,the hollow section (the forks) side walls 13. The screw or bolt-like core 22 is taken through the holes 23 and into the hollow wheel shaft 21, which has an interior thread 24 coacting with a thread 25 on the core 22. The portion of the wheel shaft 21 facing towards one side wall 13 of the ski body 10 has a flange 26 of large diameter, forming a contact surface against the side wall 13 when the core 22 is threaded into the wheel shaft 21.

[0030] The wheel shaft 21 is intended to coact with a wheel 11 or 12. The hub of the wheel 11, 12 is formed as a rim 27, as will be seen from Figure 12. The rim 27 may be of plastics and form a relatively large inner cavity 28 in the wheel 11, 12 for keeping the weight of the wheel down. The rim 27 carries a tire or a tread 29 of suitable form and pattern for roller skis. The rim 27 is formed to carry ball or roller bearings 30 at the sides of the wheel 11, 12. These bearings 30 are mounted on the wheel shaft 21 and the wheel 11, 12 is fastened to the wheel shaft 21 with a spring clip (not shown) in the annular groove 31 at the end of the wheel shaft 21.

[0031] The roller ski in accordance with the invention has been described in detail hereinbefore in connection with both the embodiments illustrated on the drawings, but it is obvious that the invention can be realized in other ways and with other materials without departing from the inventive concept as defined in the following claims. The embodiments described above and illustrated on the drawings may therefore not be regarded as restricting the invention.

Claims

1. A roller ski including a ski body (10) mounted on forward and rear wheels (11, 12), there being a binding (16 - 18) for a ski shoe being arranged between these wheels, characterized in that the ski body (10) comprises a hollow section the upper and lower walls (14, 15) of which being narrower than a normal ski shoe, the upper wall (14) having a foot deck (16, 17; 16', 17') intended for the ski shoe and just as wide as it, the deck being formed integrally with the upper wall of the hollow section close to the rear wheel (12).

2. Roller ski as claimed in claim-1, characterized in that the hollow section (10) has a rectangular cross section, its side walls (13) having greater extension than its upper and bottom walls (14, 15), said hollow section being laterally flexible for the load caused by skiing, said hollow section simultaneously supporting mounting forks (19; 19) for the forward and rear rollers (11, 12).

3. Roller ski as claimed in claim 1, characterized in that the foot deck (16, 17; 16' 17') is divided into a toe portion (16, 16') and a heel portion (17, 17').

4. Roller ski as claimed in claim 2, characterized in that the foot deck (16, 17) is centered about the longitudinal axis (20) of the ski body (10), the hollow section being joggled at its ends to form said forks (19), which are excentric of, and parallel to the hollow section (Figure 11).

5. Roller ski as claimed in claim 3, characterized in that the foot deck (16', 17') starts from the upper wall (14) of the hollow section (10) in a direction inwards the other roller ski in a pair of skis, the forward and rear wheels (11, 12) being mounted on the same side of the hollow section as the foot deck, said hollow section being substantially rectilinear.

6. Roller ski as claimed in claim 2, characterized in that in the side walls (13) of each of the forks (19; 1Y) is formed by the hollow section (10) having a through hole (23) accommodating a core (22) for a hollow shaft (21) on which the respective forward and rear wheel (11, 12) is journalled.

7. Roller ski as claimed in claim 6, characterized in that the hollow shaft (21) is formed of a lightweight material such as aluminium or plastics and the core (22) fastened to the fork (19; 19') consists of steel in the form of a screw or bolt threaded into the hollow shaft, which has a female thread (24) for this purpose.

8. Roller ski as claimed in claim 7, characterized in that each forward or rear wheel (11, 12) includes a hub (27) formed with a rim, the hub carrying bearings (30) at the sides of the wheel for the hollow shaft (21) and between these bearings forms a cavity (28) inside the wheel, the periphery of the rim carrying a tire (29).

Drawing