EP1749556A1 - Rollerski - Google Patents

Abstract

The ski has a chassis with a telescopic middle beam (15), a front support (10) at the front of the beam to mount a front wheel (12) and a rear support at the rear of the beam to mount rear wheels. The front support has an articulation (14) situated in front of the front wheel. The front support has springs for recentering the wheel (12), and ball bearings (22, 24) at the articulation to damp the impacts. A braking device with a braking bush acts on the rear wheels.

Description

Technical area

The present invention generally relates to a cross-country ski with wheels, intended for the practice of cross-country skiing on non-snow-covered terrain.

State of the art

A conventional cross-country ski has a central beam, a wheel respectively at the front and rear of the central beam and a device for attaching cross-country ski boots.

Normally, cross-country skiing is practiced on roads with a relatively smooth surface. Indeed, a classic cross-country ski is not very suitable for wood paths or bumpy paths. The wheels are generally small, the risk they block is considerable. In addition, with traditional cross-country skis, the skier takes the turns by lifting one of his skis to give it a different direction. To apply this technique on the fly requires some experience. In addition, it is not always suitable on a slightly rough ground because the skier hesitates to lift a ski.

Another problem that the athlete encounters during the practice of cross-country skiing is braking. The patent application FR 2 627 995 describes a roller ski having on the rear wheel a cable traction brake. A gripping ring is attached to the skier's belt by means of an elastic cable. To brake, the skier grasps the grip ring and pulls on the brake cable. The fact that you need to put a belt and that the braking cables hang freely next to the legs creates a certain inconvenience. In addition, to brake, the skier must use his hands that already hold the ski poles. A grip on the ring is difficult, because he has to focus at the same time on the coordination of the sticks.

Object of the invention

An object of the present invention is to provide an improved cross-country ski. This object is made by a cross-country ski as claimed in claim 1.

General description of the invention

A cross-country ski with wheels generally comprises a frame with a central beam and two supports for the wheels, one at the front of said central beam and the other at the rear. A front wheel is mounted on the front support and at least one rear wheel is mounted on the rear support. Note that the presence of a pair of rear wheels increases the stability of the wheeled ski, which will appreciate a beginner skier or one who wants to practice cross-country skiing on unpaved roads. On the other hand, a cross-country ski with only one rear wheel has the advantage of having less resistance to advancement and thus allows faster locomotion. In addition to the parts described so far, a classic cross-country ski includes a fixing device on the central beam to receive a cross-country ski boot. The fastening device allows the skier in particular to lift his heel, which constitutes a fundamental difference between a cross-country ski with wheels and a roller skate.

According to an important aspect of the invention, the front support has a hinge arranged in front of said front wheel allowing the front wheel to pivot about a substantially vertical axis. A cross-country ski with wheels according to the present invention therefore has the advantage of a directional front wheel. With a classic cross-country ski, a skier must take the turns in stages of lifting one of his skis to give him another direction than the ski on the ground. Because in a roller ski according to the invention the front wheel is pulled, the user can turn by keeping one or both skis on the ground, simply by moving his weight on the side to which he wants to turn. Naturally, for example to take tighter turns or turn on the spot, it is always possible to turn in a classic way. In addition to the simplified cornering technique, the front wheel increases ride comfort, especially on rougher terrain. Thanks to his swiveling, the front wheel can avoid small stones that are in its path. Therefore, a directional wheel is less likely to block completely, which could cause the skier to fall. A wheeled cross-country ski even better adapted to a bumpy terrain advantageously comprises wheels with a larger diameter, for example from 10 to 15 cm.

More specifically, the front support may comprise a frame rigidly connected to the central beam with two lateral sides which pass on one side and the other of the front wheel and which join in front of it. On the side of the central beam, the frame preferably has a width greater than central beam. The frame width decreases towards where the sides of the frame join in front of the wheel. The wheel itself is mounted on a fork piece, which is connected to the frame by the hinge allowing the wheel to pivot. The lateral sides of the frame make it possible to limit the pivoting movement of the front wheel. As the width of the frame decreases towards the front, the latter presents, seen from above, a shape resembling a drop or a triangle. The front wheel can rotate at an angle corresponding to the angle formed between the two lateral sides of the frame. The latter is preferentially around 15 degrees.

To further increase comfort, the front support has a shock absorber at the joint. A shock absorber will be particularly appreciated on wooden roads or on deteriorated roads. Obviously, the rear wheel support may also be equipped with a shock absorber. For even more comfort and optimized shock absorption, the wheels are advantageously inflatable.

To prevent the front wheel from striking the frame during a turn, the forked part may comprise stops cooperating with the two lateral sides of the frame. The pivoting movement of the front wheel is thus limited. The stops may be adjustable to allow the user to choose the maximum angle that can form the wheel with the longitudinal axis of the ski.

In a preferred embodiment, the front support includes recentering means for the front wheel. These refocusing means can resiliently opposing the inclination of the front wheel relative to the longitudinal axis of the ski and pulling or pushing it into the position where it is aligned with the cross-country ski. The recenter means may be arranged at the joint, but in a preferred embodiment of the invention, the recentering means comprise springs arranged between the frame and the fork member of the front support.

The present invention further provides a brake of a particular design for a cross-country ski. The proposed braking device comprises a braking pad that can act on the rear wheel (s), a brake cable and a brake control lever. The latter is arranged so that it can be actuated by the shin of a user of cross-country skiing. Upon actuation of the brake control lever, the brake cable is tensioned to engage the brake pad in a braking position. An improved brake for a cross-country ski is provided by the present invention. The brake allows the user to brake without having to move into an unstable position. He does not need to use his hands to operate the brake. The fact that the skier can use his ski poles to balance out significantly reduces his risk of falling.

Preferably, the brake control lever can be actuated by a forward movement of the user's tibia. To brake, the skier flexes his knee and his shin pushes the brake control lever forward. At the same time as braking, the user therefore lowers its center of gravity which gives it greater stability.

According to a preferred embodiment of the invention, the brake control lever can tilt forward when the skier raises the heel without the brake pad is thereby engaged in a braking position. In the technique of cross-country skiing, the skier lifts the heel of the foot momentarily at the back. The leg thus descends obliquely to the rear and is thus likely to actuate the brake control lever if it does not follow the movement of the leg. Because the brake control lever can swing forward when the heel is lifted without engaging the pad in a braking position, the skier can roll without worrying that he is touching the brake control lever. To allow tilting of the brake control lever, the braking device may include means for reducing the tension of the braking cable when the skier's heel is raised.

Advantageously, the braking device comprises a spring which, when the brake control lever is not actuated, keeps the brake pad in a rolling position and exerts a tension on the braking cable to straighten the control lever of the brake. brake. The rolling position is defined as the position of the parts of the braking device which does not prevent the wheel from rotating freely.

The skilled person will note that a cross-country ski with a brake as described above does not necessarily need to be equipped with a directional front wheel.

The total length of the cross-country ski is preferably between 60 and 90 cm, and more preferably between 60 and 70 cm. A short ski has a lower moment of inertia, which facilitates the practice of the sport and increases its attractiveness. With the swivel wheel, the directional stability of the ski is not jeopardized by the shortening of the ski. It will be noted that the cross-country ski may have a mechanism for varying the length, e.g. ex. a telescopic central beam. Each user can thus adjust the length of the ski according to his own needs.

Brief description of the drawings

• Fig. 1: une vue longitudinale d'un support de la roue avant ;
• Fig. 2: une vue horizontale du dispositif de la Fig. 1 ;
• Fig. 3: une vue longitudinale d'un dispositif de freinage de la roue arrière lorsque le skieur l'actionne ;
• Fig. 4: une vue longitudinale d'un dispositif de freinage de la roue arrière lorsque le skieur n'actionne pas le frein mais garde le talon en contact du ski;
• Fig. 5: une vue longitudinale d'un dispositif de freinage de la roue arrière lorsque le skieur lève le talon.

Other features and characteristics of the invention will become apparent from the detailed description of an advantageous embodiment presented below, by way of illustration. Reference is made to the accompanying drawings, which show:

• Fig. 1: a longitudinal view of a support of the front wheel;
• Fig. 2: a horizontal view of the device of FIG. 1;
• Fig. 3: a longitudinal view of a braking device of the rear wheel when the skier actuates it;
• Fig. 4: a longitudinal view of a braking device of the rear wheel when the skier does not actuate the brake but keeps the heel in contact with the ski;
• Fig. 5: a longitudinal view of a braking device of the rear wheel when the skier lifts the heel.

Description of a preferred execution

Figure 1 shows a longitudinal view, Figure 2 a horizontal view of a support 10 of the front wheel 12 of a cross-country ski with wheels. The support 10 comprises a frame 16, a fork piece 18 and a hinge 14, arranged at the front of the wheel 12, which connects the frame 16 to the fork piece 18. The wheel 12 is mounted on the fork piece so as to freely rotate about its axis 34. With the hinge 14, the fork piece 18 can, together with the wheel 12, pivot about the axis 20 passing vertically by the hinge 14. The piece fork 18 is held movable relative to the frame 16 by ball bearings 22, 24. The frame 16 is suspended from the fork member by means of a spring 26. A pin 28 is housed on the axis 20 of the hinge 14 and attached to the fork member 18. At the lower end, the pin 28 has a thread for screwing a nut 30. The ball bearing 24 rests on the nut 30 and serves as a support for the spring 26 The other side of the spring 26 bears against the ball bearing 22 and presses it against the upper wall 1e of the cylindrical housing 32, which is integral with the frame 16. The ball bearing 22 serves as a guide for the pin 28, which can perform a reciprocating movement relative to the cylindrical housing 32 to dampen shocks. A stop 36, comprising for example a polyethylene or Teflon washer, is arranged between the upper wall of the housing 32 and the fork piece 18, to prevent these two parts from colliding when the wheeled ski is not or little loaded. The abutment 36 advantageously comprises another ball bearing for reducing the friction between the cylindrical casing 32 and the fork piece 18.

The wheel 12 is preferably an inflatable wheel with a diameter of 10 to 15 cm. Higher wheel size makes it easier to ride on a floor accident, on which rollers with a normal diameter (6 to 8 cm) would block. To avoid that with wide wheels the skier is too far from the ground, the frame 16 is located below the axis 34 of the front wheel. It should be noted that the greater the distance from the ground to the foot, the more difficult it is to remain balanced on the ski. In addition, the risk of the skier stepping on his foot during a fall increases with the distance from the ground.

Seen from above, the frame 16 has a shape resembling a drop. The width of the frame 16 at the rear of the wheel 12 is greater than the width of the central beam 15. The pivoting movement of the wheel 12 is limited by the angle formed between the two lateral sides of the frame 16. This angle is preferably between 10 and 15 degrees.

The fork piece 18 goes down from the hinge 14 towards the axis 34 of the front wheel 12. Beyond the axis 34, relative to the hinge, the arms of the fork member extend to form stops 36. These abut against the frame 16 to limit the pivoting movement of the wheel 12 about the axis 20. The stops 36 may comprise a buffer of elastic material to absorb the shock when the stops hit the frame 16.

To recenter the wheel 12, springs 38, 40 are arranged on both sides of the wheel 12 between the fork piece 18 and the frame 16. In a right turn, the rear of the wheel 12 goes to the left . The left spring 38 is compressed and the right spring 40 is stretched. The springs 38, 40 therefore contribute to recentering the wheel 12 until it is again aligned with the central beam 15.

Figures 3, 4 and 5 show a longitudinal view of the rear part of the cross-country ski with wheels. At the rear of the central beam 15, a support 41 of the or rear wheel 42 is fixed to the central beam 15. The cross-country ski has a braking device with a brake pad 44, a braking cable 46 and a brake control lever 48. When a force 50 is exerted on the lever 48, the cable 46 is tensioned and the brake pad comes into contact with the wheel 42.

The brake control lever 48 is arranged so that on the central beam 15 of the chassis it allows the skier to brake with the shin 64. At or near the central beam 15, the lever 48 is mounted on a substantially horizontal and transverse axis 52, which allows the upper portion of the lever 48 to pivot forwardly. The shaft 52 is housed held in a support piece 66 so as to slide obliquely relative to the direction of the bearing. For this purpose, the support piece 66 has oblong holes 68 inclined relative to the horizontal in which the axis 52 can slide. In a variant of this embodiment, the axis 52 is fixed to the support piece 52, and the oblong holes 68 are present on the brake control lever 48.

The attachment 70 makes it possible to attach a cross-country ski boot 72 to the central beam 15 movably about an axis 74 situated at the front of the boot 72 so that the skier can lift the heel. The attachment 70 is further provided with a deflection member 76 which deflects the braking cable 46 to an attachment point 54 on the brake control lever 48.

The cable 46 is deflected by a pair of deflection pulleys 56 and returned to the rear wheel 42 through a hollow space in the central beam 15. Another deflection pulley 58 returns the cable 46 to a brake lever 60, which comprises the brake pad 44.

To brake, the skier flexes the knee while keeping the heel in contact with the central beam 15 (Fig. 3). The tibia 64 then pushes the top of the lever 48 forward. The attachment point 54 is moved forward which increases the distance between the deflection member 76 and the attachment point 54. Simultaneously, the axis 52 slides obliquely forward and the boss 78 of the lever brake control pushes on the cable 46. Of these facts, the braking cable 46 is stretched. The pulleys 58, 56 transmit the tension of the cable 46 to the brake lever 60 and the brake pad 44 is brought into contact with the rear wheel 42. A spring 62 between the brake lever and the support 41 is stretched when the brake is actuated.

When the skier releases pressure on the control lever 48, the spring 62 rectifies the brake lever 60 and thereby brings the brake pad 44 into the rolling position (Fig. 4). At the same time, a tension is created on the cable 46, which brings the brake control lever 48 back into its rolling position: the top of the lever 48 is moved rearward, while the tension of the cable 46 causes the brake to slide. 52 axis rearward in the oblong guide holes 68.

To roll, the axis 52 of the brake control lever 48 is held in the upper rear part of the oblong hole 68 by the tension of the cable 46. When the skier raises the heel, as shown in FIG. deflection 76 of the fastener 70 tilts forwards and approaches the point of attachment 54 of the cable to the brake control lever 48. The tension on the cable 46 is thus released, which allows the control lever to brake 48 to swing forward without the brake being actuated.

When the cross-country ski has two rear wheels 42, these are preferably rotatably mounted on an axle that can pivot about a fixed axis of the central beam and inclined relative to the vertical. With this, the skier can, by the lateral displacement of its weight, tilt the cross-country ski on one side and thus cause a turning of the rear axle, as on a skateboard. Advantageously, this steering device comprises a means for limiting the inclination of the ski and the steering.

Claims (10)

Cross-country skiing with wheels
a frame with a central beam, a front support at the front of said central beam on which is mounted a front wheel and a rear support at the rear of said central beam on which is mounted at least one rear wheel;
characterized in that said front support has a hinge in front of said front wheel allowing said front wheel to pivot about a substantially vertical axis. A cross-country ski as claimed in claim 1, wherein said front support comprises: a frame rigidly connected to said central beam, having two lateral sides which pass on either side of said front wheel and which join in front of said front wheel, said frame having, on the side of the central beam, a width greater than said central beam and the width of said frame decreasing towards where said sides join; and a forked part connected by said hinge to said frame, on which is mounted said front wheel. A cross-country ski as claimed in claim 2, wherein said front support includes a shock absorber at said hinge. Cross-country ski as claimed in claim 2 or 3, wherein said forked part comprises stops cooperating with both lateral sides of said frame in order to limit a pivoting movement of said front wheel. Cross-country ski according to one of claims 2 to 4, wherein said support comprises means for refocusing the front wheel. Cross-country skiing according to one of claims 2 to 5, wherein the recentering means comprise springs arranged between said forked part and said frame. Wheeled cross-country ski according to one of claims 1 to 6, comprising a braking device with a braking pad acting on said rear wheel (s), a brake cable and a control lever brake actuatable by the tibia of a user of said cross-country ski, wherein the brake cable can be tensioned by actuation of said brake control lever to engage said brake pad in a braking position. A cross-country ski as claimed in claim 7, wherein said brake control lever can be actuated by a forward movement of the user's tibia. Wheeled cross-country ski according to one of claims 7 to 8, comprising a fixing device on the central beam for receiving a cross-country ski boot and allowing a skier to lift the heel, in which said brake control lever can perform a forward tilting when the skier raises the heel without said braking pad being thereby engaged in a braking position. A cross-country ski as claimed in one of claims 7 to 9, wherein said braking device comprises a spring which, when said brake control lever is not actuated, maintains said brake pad in a rolling position and exerts a tension on said brake cable for rectifying said brake control lever.

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