EP1383584B1 - Underframe with controlled deformation for gliding craft, in particular for skate-board - Google Patents

Abstract

The invention concerns an underframe with controlled deformation for a gliding craft, in particular for a skateboard, characterised in that it comprises a structure with a central platform ( 12 ), a front platform ( 14 ) and a rear platform ( 16 ), the platforms comprising a box-type arrangement with a pressure surface ( 12 - 1, 14 - 1 and 16 - 1 ) and a suction surface ( 12 - 2, 14 - 2 and 16 - 2 ).

Description

The present invention relates to a chassis with controlled deformation for a gliding machine, in particular for a skateboard.

A basic skateboard consists of a so-called plateau board, having a given flexibility and two shafts equipped at their ends with wheels mounted free to rotate, said wheels wearing solid tires generally elastomer, quality adapted to evolutions sought.

The shafts are each secured to a support attached to a block of elastomeric material. This block has deformation capacities proportional to the stiffness of the elastomer and this deformation capacity allows orientations of the shaft relative to the longitudinal axis of the board.

The user, by its position on the plate carries its weight transversely, on one side or the other, so as to obtain the desired deformation of the block and the desired orientation of the wheel axles. The skateboard can thus be driven by the position of the user. Nevertheless, the orientation angle remains low and the turning radius is large.

Such a vehicle remains unwieldy especially when the board is of great length called "longboard" or it would be useful to take tight turns.

In the particular case of a machine with pneumatic tires and possibly propelled, the patent application French N ° 2 784 302 described an arrangement with a deformable parallelogram which accentuates the steering effect and especially which allows a tilting of the wheels. Such an arrangement, in addition to being mechanically complex, is incompatible with a skateboard having a low ground clearance as it should to facilitate the climb and ensure a perfect balance leaving the center of gravity as low as possible. In addition, the control of the deformation of the parallelogram remains an unresolved problem in this patent application.

This deformable parallelogram assembly remains reserved for large machines, with high ground clearance and wheels with tires.

The patent US-A-5,540,455 offers a refinement to greatly improve steering capabilities. Indeed, this patent proposes to achieve a platinum with two platforms articulated with respect to each other. The user then places one foot on each platform and can direct each of them as he wishes. A spring is interposed to form this articulation.

This makes it possible to increase the number of combinations of orientations of the trees, but it is also understood that the conduct of such a structure is difficult because the orientations of the two shafts may be opposite, which causes radical movements or even dangerous. In addition, the two parts can tilt in the longitudinal direction also forming a V in the axis of advance, which is not satisfactory.

The patent application European N ° 933 103 discloses an oscillating arm arrangement mounted on a turntable. If such an arrangement can provide a certain comfort compared to the coating on which the skateboard moves, it does not meet the problem of turning while having perfect control of this steering. Moreover, the complexity of such an embodiment makes such an arrangement incompatible with the market or reserved for an elite.

The present invention aims at a chassis with controlled deformation for a gliding machine, in particular for a skateboard which is controllable in its piloting, which is sensitive to the distribution of weight transversely but also longitudinally, which is of an embodiment compatible with industrial production, which is of simplified maintenance and total reliability since it is about structural elements and not reported mechanical moving elements.

According to another object, the controlled-deformation chassis of the invention improves steering by making it more progressive.

According to another object, the controlled deformation chassis of the invention can be adapted and adjusted according to the user by a few simple modifications.

• figures 1A et 1B, une vue schématique en perspective et de dessus du châssis selon un mode de réalisation préféré de la présente invention, avec des bras indépendants,
• figure 2, une vue en coupe longitudinale du châssis de la figure 1,
• figure 3, une vue en coupe transversale suivant la ligne 3-3 de la figure 2,
• figure 4, une vue de dessus montrant la déformation engendrée par un effort exercé par l'utilisateur sur le côté droit par rapport au sens d'avancement, et en position avant/arrière centrée
• figure 5, une vue de dessus montrant la déformation engendrée par un effort exercé par l'utilisateur sur le côté droit par rapport au sens d'avancement, et en position décentrée longitudinalement sur l'avant,
• figure 6, une vue en élévation latérale schématique permettant de constater la reprise de la charge.

The invention is now described in detail with reference to the appended drawings which represent a particular and preferred but non-limiting embodiment, the various figures show:

• FIGS. 1A and 1B, a schematic view in perspective and from above of the frame according to a preferred embodiment of the present invention, with independent arms,
• FIG. 2 is a view in longitudinal section of the frame of FIG.
• FIG. 3, a cross-sectional view along the line 3-3 of FIG. 2,
• FIG. 4 is a view from above showing the deformation caused by a force exerted by the user on the right side relative to the direction of travel, and in the forward / backward centered position.
• FIG. 5, a view from above showing the deformation generated by a force exerted by the user on the right side with respect to the direction of travel, and in the off-center position longitudinally on the front,
• FIG. 6 is a diagrammatic side elevation showing the recovery of the load.

The present invention is now described in its structure with reference to FIGS. 1 to 3.

The chassis comprises a structure 10 with a central plate 12, a front plate 14 and a rear plate 16, both integral with the central plate. These plates have a box arrangement with a lower surface 12-1, 14-1 and 16-1 and an upper surface 12-2, 14-2 and 16-2.

The terms intrados and extrados relate in the present application to a structure subjected to mechanical stresses, by analogy to a bridge, the extrados corresponding to the upper part working in compression and the intrados to the lower part working in tension. It is understood that the upper surface may have a concave profile, not shown in the figures.

In the preferred embodiment, each front and rear stage is composed of two independent arms 14g, 14d; 16g, 16d each carrying a wheel 17 or pad, mounted free to rotate on a shaft.

Each of the front and rear plates is secured to the central plate 12, in this case by a transverse spacer 18 and 20, as a U- shaped profile , made of composite material so as to give the wings of each U- profile elastic capabilities return in both directions and form a joint. These spacers ensure spacing between the upper and lower surfaces.

These U- shaped profiles are the simplest and most used, readily available commercially but any other form W or double U or with variable dimensions both transversely and longitudinally are immediately applicable depending on the applications, such a choice being the scope of the man of the art. The essential function of these spacer elements is to allow a deformation of the frame, in particular a bending movement in the horizontal plane.

These profiles have their base in the plane of the intrados. In addition, one of the wings of each section is integral with the upper surface of the front plate or rear and the other is secured to the upper surface of the central portion. These U- shaped profiles thus work in flexion, compression and traction according to the movements.

One of the most important and essential elements of the invention is a longitudinal column 22, preferably in the middle position for reasons of symmetry. This column is arranged in the central plate and has a high stiffness. This column is deformable in the horizontal plane and / or vertical and connected to the two front and rear plates. In the mode of realization, this column connects the spacers U parallel to the extrados 12-2 of the central part. This column works in bending and / or compression. It provides an elastic return against the deformations generated by the movements of the user.

This central plate is equipped with at least one transverse spacer 24, identical to the spacers 18 and 20, dimensioned as will be explained later. This spacer also ensures spacing between the upper and lower surfaces. This spacer is shown in the middle position in the embodiment but it can be decentered according to the desired effects.

Thus the extrados 12-2 of the central portion is also made in two parts each connected to one of the U- shaped profile while the base is linked to the intrados 12-1.

Thus the two front and rear plates are articulated relative to the central portion and this central portion itself comprises a central joint.

There is further provided means 26 for taking up the vertical load which constitute the intrados. These means comprise at least one tendon, in this case two longitudinal tendons 28, both linked to the front and rear plates and working in traction and passing under the central plate.

Thus, for any load exerted on the upper surface, the tendons work in traction and the median longitudinal column 22, in addition to working in bending and providing an elastic return in the horizontal plane, also works in compression by participating in the recovery some efforts.

As shown in FIG. 4, the user exerts a force on the right side with respect to the forward direction F. The two sets of wheels are oriented symmetrically along the curve C because the user is in the forward / backward centered position. The median transverse spacer 24 and the median longitudinal column 22 work mainly.

In Figure 5, the user exerts his effort always on the right side relative to the direction of travel, but in the biased position longitudinally on the front. We notice that there is more deformation pronounced on the front following a curve C1 which leads to a tighter curvature while the rear follows a C2 curve with a larger turning radius.

Indeed, in this case, the medial transverse spacer 24 and the middle longitudinal column 22 are mainly biased but in addition, the front spacer 18 is deformed. Thus, the front axle rotates with a steering angle which is the sum of the two deformations, which gives this curvature more pronounced.

In these Figures 4 and 5, there is the deformation of the different spacers whose wings are close to ensure an angular deformation.

During the differentiated steering movements, there is a stimulus effect because the thrust of the user's support, in addition to the centrifugal force, causes a motor action.

Note also that in this arrangement according to the present invention, the chassis is particularly stable regardless of the speed. Indeed, this double deformation is not subject to velocity effects and no instability effect is recorded at high speed.

In axle assemblies on elastomer block is the adjustment is hard and the machine is more stable at high speed but not very maneuverable or the setting is flexible to be manageable and the machine quickly becomes unstable as soon as the speed increases.

For the frame of the present invention, one can adjust the elastic return force of the wings of the spacers because the U- shaped allows to introduce an elastomeric foam bread for example. The density of this elastomeric foam and its internal structure with open or closed cells allow fine adjustments depending on the weight of the user in particular.

Alternatively, one can also provide other elastic return elements such as springs or flexible blades.

It is also possible to provide means 30 for clamping the column, adjustable so as to cure more or less the reactivity of this column. Thus such means may comprise a cable embedded with a system of tensioners.

Similarly, in FIG. 6, it can be seen that the recovery of the user's weight is carried out by the tendons whose elastic return capacity also makes it possible to adjust the flexibility of the load, consisting of the weight of the user and the dynamic effects.

When the user is on one side, the lateral imbalance causes a turnaround that is all the more important that the supports are close to the middle of the board. Thus the user can control the maneuverability and stability of the chassis by moving the supports.

The embodiments presented have been simplified with spacers in low numbers but, depending on the needs and calculations, it is also possible to multiply these spacers so as to achieve a spine type "fishbone" .

It is important to note that the controlled deformation frame of the invention comprises a front portion and a rear portion connected through a central portion, the assembly forming a box structure with a moment of inertia in the relatively long vertical median longitudinal plane so as to include the effort exerted by the weight of the user, said structure having a lower resistance to allow bending deformation in the horizontal plane. This arrangement makes it possible, during the displacement of the load, to induce a deformation of the structure allowing steering, as represented for example by FIGS. 4 and 5.

By way of example, the central part may be made of a block of foamable material, for example foam, with non-uniform properties so as to obtain the box structure specified above.

According to another embodiment, the central portion may comprise a rigid plate connected respectively to the front portion and to the rear portion by an element, in particular a column disposed in the longitudinal median plane, so as to obtain the box structure specified herein. -above.

According to another embodiment, the central portion may comprise two plates rigidly connected to one at the front part and the other at the rear part, the two boards being connected by an element, in particular a column arranged in the longitudinal median plane, so as to obtain the box structure specified above.

According to another embodiment, the central portion may comprise a box shape with cross-stiffening elements arranged at the diagonals, so as to obtain the box structure specified above.

For all the variants, the presence of at least one longitudinal tendon, working in traction, connecting the front and rear parts, disposed at the intrados is necessary.

In the arrangements resulting from the main embodiment, there may be mentioned a skateboard with three wheels instead of four since this is sufficient for stability and still benefits from the structure presented above.

It is noted in the device described in the main that the wheels, mounted on oscillating arms allow the introduction of at least one braking element or at least slowing down on a wheel set. The larger diameter allows to consider industrial manufacturing using proven and simple techniques so a cost price of interesting products, for example by adapting manufacturing techniques for bicycle wheels or trolley.

Claims (12)

1. A chassis with controlled deformation for a sliding appliance, in particular for a skateboard, characterised in that it comprises a structure (10) with a central plate (12), a front plate (14) and a rear plate (16), these plates comprising a box arrangement with an intrados(12-1, 14-1 and 16-1) and an extrados (12-2, 14-2 and 16-2).
2. A chassis with controlled deformation for a sliding appliance according to claim 1, characterised in that the central plate (12) comprises at least one element (22), deformable in the horizontal and/or vertical plane, working under flexion and/or compression.
3. A chassis with controlled deformation for a sliding appliance according to either one of the preceding claims, characterised in that each front (14) and rear (16) plate is composed of two independent arms (14g, 14d; 16g, 16d) each carrying a wheel (17), mounted so as to rotate freely on a shaft.
4. A chassis with controlled deformation for a sliding appliance according to any one of the preceding claims, characterised in that it comprises means (26) for taking up the vertical load forming the intrados.
5. A chassis with controlled deformation for a sliding appliance according to claim 4, characterised in that the means (26) for taking up the vertical load comprise at least one longitudinal tendon (28) working under traction, disposed between the front and rear plates and passing under the central plate.
6. A chassis with controlled deformation for a sliding appliance according to claims 1, 2 or 3, characterised in that each of the front (14) and rear (16) plates is connected to the central plate (12) by at least one middle longitudinal column (22).
7. A chassis with controlled deformation for a sliding appliance according to claim 6, characterised in that each of the front (14) and rear (16) plates is connected to the central plate (12) by a transverse strut (18) and (20), allowing deformations of the chassis, particularly under flexion in the horizontal plane.
8. A chassis with controlled deformation for a sliding appliance according to claim 7, characterised in that each transverse strut (18) is disposed between the extrados and the intrados to ensure spacing thereof.
9. A chassis with controlled deformation for a sliding appliance according to claim 7 or 8, characterised in that each profile of each transverse strut (18) and (20) has its base in abutment on the intrados and part of each profile is fixed to the extrados of the front or rear plate and another part is fixed to the extrados of the central plate, so as to make these profiles work under flexion.
10. A chassis with controlled deformation for a sliding appliance according to any one of claims 7 to 9, characterised in that each transverse strut (18) and (20) has a U-shaped profile.
11. A chassis with controlled deformation for a sliding appliance according to any one of the preceding claims, characterised in that the central plate (12) is equipped with at least one transverse strut (24).
12. A chassis with controlled deformation for a sliding appliance according to claim 11, characterised in that the extrados (12-2) of the central part (12) is produced in two parts each connected to one of the wings of the U-shaped profile of the strut (24) while the base is connected to the intrados (12-1).

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