FR2611517A1 - PROFILE BOX SKI - Google Patents

Abstract

THE SKI ACCORDING TO THE INVENTION INCLUDES A BOX STRUCTURE IN WHICH THE LATERAL RESISTANCE WALLS 222, 223 HAVE AN INCLINATION WHICH VARIES DEPENDING ON THE POSITION CONSIDERED ALONG THE SKI: IN THE CENTRAL ZONE, THE LATERAL RESISTANCE WALLS 222, 223 ARE CLOSE TO VERTICAL, WHILE THEY INCLINE PROGRESSIVELY WHEN YOU APPROACH THE EXTREMITIES OF THE SKI.

Description

2 6 1 1517

PROFILE BOX SKI

  The present invention relates to skis used in sports

  winter, and intended to slide on snow and ice.

  The skis generally have a lower sliding face.

  ment connecting to two lateral faces along two lower edges provided with metal edges, the lateral faces connecting to an upper face. The skis have a relatively small width compared to their length, thus defining a longitudinal direction, their front end being curved upward to form a spatula. The upper face of the ski has an intermediate zone, or

  fastening area, for fastening a user's shoe.

  In traditional skis, the thickness of the ski body varies according to the longitudinal position considered, and has a maximum in the mounting area of the binding, area in which the

  bending moments are generally highest during use.

  tion of skiing. The greater thickness in the center and thinner in the vicinity of the ends simultaneously ensures uniform distribution

  of the load, as taught for example the patent FR-A-985 174.

  Furthermore, the plaintiff has already described, in French applications n 86 07849, 86 07850, 86 07851 and 86 07852, external forms of skis in which the lateral faces or edges have variable inclinations, the lateral faces being intended to enter in contact with snow to obtain effects

  individuals especially during turns.

  Regarding the internal structure of the ski, current skis generally have a composite structure in which different materials are combined so that each of them intervenes

  optimally, taking into account the distribution of mechanical stresses

  ques. The structure comprises resistance elements or resistance blades, made of a material having a high resistance and a great stiffness, in order to resist the bending and torsion stresses appearing in the ski. The structure also includes in particular

filling elements.

  The two main modern composite structures which have given rise to large-scale applications in skiing are the

  sandwich structure and box structure.

  In the case of a sandwich structure, described for example in documents FR-A-1,124,600 (Figures 1 and 2) and FR-A-2,069,824, the ski comprises a central core, made of cellular material which can be partially hollow, reinforced above and below respectively by an upper resistance blade and a lower resistance blade, the resistance blades having strength and stiffness qualities

  greater than those of the nucleus itself.

  It has been observed that the sandwich structures make it possible to produce the skis which have the best gliding in direct tracks, that is to say in displacement in the longitudinal direction of the ski. On the other hand, their lateral attachment qualities on slopes or in turns are not optimal, and for this reason they prefer box structure skis. In the box structure, described for example in documents FR-A985 174, FR-A-1,124,600 (Figure 3), the ski comprises an internal core of cellular material which may be partially hollow, the core being surrounded by the elements of resistance arranged in blades and

partitions constituting a box.

  The box structure gives the ski elastic properties.

  cited and superior mechanical strength in bending, and a large

  resistance to torsion along the longitudinal axis.

  It is found that it follows that such skis with box structure have optimal qualities of lateral attachment on slopes or when cornering on snow. However, they are less efficient than

  sandwich structure skis with regard to sliding qualities.

  Like the external shape of the ski, the box has a variable thickness depending on the longitudinal zone considered of the ski, according to this the external shape of the ski. Despite this variable thickness, which results in giving the box a greater thickness and rigidity in the center of the ski and lower in the vicinity of the ends, it can be seen that the intrinsic properties of the box

  disadvantage the sliding of the ski, compared to a sandwich structure.

  This results in a need to specialize skis, depending on the type of use that one wants to make of it, and one can choose a ski with a sandwich structure to obtain high speed, for example in downhill competition, and choose a ski with a box structure to obtain a good grip on the ice, for example in slalom competition.

2 6 1 1 5 1 7

  The object of the present invention is in particular to avoid the drawbacks of known ski structures, by proposing a new structure which confers on the ski simultaneously optimal sliding qualities such as those of skis with sandwich structure, and optimal gripping qualities such as those of box structure skis. According to another object of the invention, in a ski with box structure, the invention aims to define new means giving the ski body variable resistance properties depending on the position

  longitudinal considered, without appreciably altering the properties

  tees obtained by the box structure, but making it possible to improve

noticeably slips.

  Another object of the present invention is to obtain a

  advantageously continuous variation of the mechanical strength properties

  as a function of the longitudinal position considered of the ski body, without major modification of structure, thus achieving a homogeneity of structure and behavior, a good distribution of reactions along the ski, giving the user an impression of comfort and

regularity of ski reactions.

  Another object of the invention is to define means making it possible to combine, in the same ski, the sliding and gripping properties obtained by the new structure and the properties of reaction with snow obtained by the external forms of the ski to

variable inclined edges.

  To achieve these and other objects, the present invention provides a ski whose body comprises, substantially over its entire length, a core surrounded by a box of mechanical resistance, the box comprising a blade of upper resistance integral with two walls of lateral resistance elements themselves integral with a lower resistance blade, at least one of the lateral resistance walls having, with respect to the lower resistance blade, an internal angle of inclination A which varies along the body of the ski in function of the longitudinal position considered; this variable inclination gives the ski body mechanical resistance properties which are variable as a function of the longitudinal position considered; it can be assumed that portions of the box in which the angles of inclination A are close to 90 'behave mechanically like a box

26 115 17

  traditional, while the portions in which the angles A are close to 0 behave mechanically rather like a sandwich structure, the overall structure of the ski body remaining however

  homogeneous, with a core surrounded by a mechanical resistance box.

  According to one embodiment of the invention, the angle of inclination A in the central zone of the ski, or binding zone, is greater than the angle of inclination in the vicinity of at least one of the ends of the ski contact area. It has been found that such a distribution of the angle of inclination makes it possible to keep the ski

  grip qualities of a traditional box ski, while improving

  significantly increasing its sliding properties. This phenomenon is all the more marked when it is the vicinity of the front contact line of the ski which has a low tilt value A, or when it is the two front and rear contact lines which, in their vicinity,

  have a low tilt angle A.

  We can advantageously provide a longitudinal symmetry of the ski by having symmetrically lateral resistance walls one

  on the other with respect to a median longitudinal vertical plane of the ski.

  Sliding improvement properties are obtained

  also when the lateral resistance walls are asymmetrical

  ques, the asymmetry can be achieved with respect to the median longitudinal vertical plane of the ski, or additionally accompanied by a variable asymmetry as a function of the longitudinal position considered along the ski. According to one embodiment, the angle of inclination A is at most equal to 90, over the entire length of the box. The angle of inclination A can advantageously take a value very close to 90 in the central area of the ski body, achieving the maximum effect of a structure

box type.

  In the vicinity of at least one of the two contact lines,

  the angle of inclination A can advantageously be chosen to be small, in particular

less than 10.

  Preferably, the angle of inclination A varies continuously along the ski body, producing a variation in resistance

mechanical continues.

  According to one embodiment of the invention, the lateral resistance walls are substantially parallel to the corresponding external lateral faces of the ski. We then combine the effects of the external shape of the ski, allowing, for example, an advantageous behavior when cornering, with the effects of the particular structure of a box with variable angle of inclination, that is to say with good grip and a good skiing. Other objects, features and advantages of this

  The invention will emerge from the following description of embodiments.

  tion particular, made in connection with the attached figures, among which: - Figure 1 shows a perspective view of a ski according to the invention; - Figure 2 shows a top view of the ski of Figure 1; - Figure 3 shows a side view of the ski of Figure I; - Figures 4, 5, 6, 7 and 8 respectively represent cross sections of the ski of Figure 2 according to the vetical planes B-B, C-C, DD, E-E and F-F; - Figure 9 shows a top view of another embodiment of the ski according to the invention, the ski having a variable asymmetry depending on the longitudinal position considered; - Figures 10, 11 and 12 respectively show sectional views

  transverse of the ski of FIG. 9 along the vertical planes Cl-Cl, D1-

  D1, El-El; - Figure 13 shows a top view of another embodiment of the ski according to the invention, having another form of asymmetry by lateral translation of the upper face of the ski relative to the lower face of the ski; - Figures 14 and 15 respectively represent cross-sectional views of the ski according to Figure 13 according to the plans C2-C2.et E2-E2; - Figure 16 illustrates an embodiment according to the invention in which the lateral faces of the box are convex; - Figure 17 shows an embodiment in which the side faces of the box are concave; and - Figure 18 shows an embodiment in which the face

upper part of the box is concave.

  As shown in the figures, a ski according to the present invention generally comprises an upper face 1, a lower face 2 or sliding surface, a first lateral face 3, a second lateral face 4, a front end curved upwards in tip shape 5. The underside 2 of the ski is arched upwards between the front contact line 6 and the rear contact line 7. The ski body, or part of the ski comprised between the front contact line 6 and the rear contact line 7, has a maximum thickness in its central zone 8, and a thickness which gradually decreases

  when we approach the front contact lines 6 and rear 7.

  In the embodiment shown in Figures 1 to 8, the ski has a box structure of mechanical resistance

  symmetrical with respect to the median longitudinal vertical axis I-I of the ski.

  FIG. 6 represents a cross section of the ski in the vicinity of its central zone 8, section along the plane D-D. In this section, we see that the ski consists of three main parts: a core 10, of substantially rectangular section, a shell 20, and an element

lower 30.

  The core 10 can be made of different materials, such as wood or synthetic foam, or other cellular structures and for example aluminum honeycomb; the nucleus can also be partially

  hollow, consisting for example of metal or plastic tubes.

  The shell 20, in the embodiment shown, is a composite shell comprising an outer layer of appearance 21, for example made of thermoplastic material, and a reinforcing layer 22 made of a material with high mechanical resistance such as a

  laminate or aluminum alloy. An inner layer of filling

  ge 23 provides the connection between the core 10 and the reinforcing layer 22.

  For example, the outer layer 21 is made of thermoplastic material.

  tick such as acrylonitrile butadiene styrene, commonly

  designated by ABS, or a polyamide, or a polycarbonate.

  The reinforcing layer 22 can be produced from one or more sheets of glass, carbon or other fabric, these layers being advantageously prepreg of thermoplastic resins such as polyetimimides, or thermosetting resins such as epoxides or polyurethanes . The glass fabric or the like is of the rather unidirectional type, and comprises for example 90% of fibers in the lengthwise direction of the ski, and 10% in the transverse direction. The reinforcing layer 22 can also be made of a metal alloy with a high elastic limit or of metallic glasses, or even in a combination

261 '15 1 7

of these two materials.

  The filling layer 23 can be made of thermoplastic material, either of the same nature as the outer layer, or of a different nature, for example of a nature such that the softening point is lower. The lower element 30 comprises a sole 31 of polyethylene constituting the lower face 2 of the ski or gliding surface, lateral edges of steel 32 and 33, and a lower resistance blade 34 of a mechanically resistant material. For example, the lower resistance blade 34 may have a composite structure, comprising a lower layer 341 of glass fibers and an upper layer 342 of aluminum alloy or laminate. The lower resistance blade 34 is secured, along its lateral edges, to the lower lateral edges

  corresponding to the reinforcing layer 22 of the shell 20.

  The reinforcing layer 22 of the shell 20 has, as shown in the figure, an inverted U-shaped structure, constituting an upper resistance strip 221, itself connecting to two lateral resistance walls 222 and 223 secured to their lower edges at the lateral edges of the lower resistance blade 34. In this way, the reinforcing layer 22 of the shell and the lower resistance blade

  34 constitute a closed box structure, surrounding the core 10.

  As shown in Figures 4 to 8, the shape and dimensions in section of the box vary depending on the area considered along the ski. Thus, in the central zone shown in FIG. 6, the box has a trapezoidal section with lateral resistance walls 222 and 223 slightly inclined relative to the median longitudinal plane I-I of the ski. Thus, the lateral resistance walls 222 and 223 define, with the lower resistance blade 34, an angle

  interior A, or tilt angle, whose value is close to 90.

  In FIG. 7, in the rear intermediate zone E-E of the ski, the height of the box is lower, and the angle of inclination A is lower, for example of the order of 70 as shown in the figure. In the vicinity of the rear contact line, in the area FF, FIG. 8 shows that the box is then very flattened, its thickness being small, and, simultaneously, the angle of inclination A is small, for example 10 to 20 as shown in Figure 8. The core 10 has a

very small thickness.

  Similarly, in the front intermediate zone of the ski shown in FIG. 5, or zone according to the section CC, the box has a reduced height and the angle of inclination A is small, for example close to 45 as shown in the figure . And in the vicinity of the front contact line 6, the box is very flattened and is made up of two upper and lower resistance blades glued to one another; we can then consider that

  the angle of inclination A is less than 10, or even zero.

  The structure of Figure 6 is a traditional box structure, while the structure of Figure 4 or Figure 8, although being box-shaped, has the behavior of a sandwich type structure, in fact that the angle A is small. The transition from one to the other takes place gradually, by progressive reduction of the thickness of the ski and simultaneous reduction of the angle of inclination A, when one passes from the central zone of the ski represented on the figure

  6 to an end zone shown in FIG. 4 or in FIG. 8.

  Without departing from the scope of the present invention, it is possible to provide a symmetrical structure of the type of FIGS. 1 to 8 while choosing construction variants. For example, a ski structure according to the invention can be defined in which, in the central area of the ski, the lateral resistance walls 222 and 223 are substantially

  vertical, the angle of inclination A then being close to 90.

  In another embodiment, it is possible to provide in the central zone an angle of inclination A of less than 90, for example 80 as

represents it in figure 6.

  It is also possible to provide a homogeneous lower resistance blade 34, comprising a single layer of resistant material, or more than

two layers.

  The presence of the outer layer 21 is not essential for obtaining the particular effects according to the invention, and a ski structure can be defined in which the outer layer 21 and the

  reinforcing layer 22 are one and the same reinforcing layer.

  These same variants can be applied in the embodiments which will be described below, in which the ski

  has an asymmetrical structure in cross section.

  In the embodiment shown in FIGS. 9 to 12, the ski according to the invention has a variable asymmetry along the ski body as a function of the longitudinal position considered. Thus, in the front area of the ski, as shown in section Cl-Cl in FIG. 10, the first lateral resistance wall 222 of the box has a tilt angle Ai smaller than the tilt angle A2 of the second side resistance wall 223; on the other hand, in the rear zone, represented in section in FIG. 12, the angle Ai is greater than the angle A2, and, in the central zone of the ski represented in

  section in Figure 11, the angles A1 and A2 are equal.

  In the embodiment shown in FIGS. 13 to 15, the ski is also asymmetrical, and the asymmetry is always in the same direction relative to the median longitudinal plane I-I of the ski. In this case, the tilt angle Ai is greater than the tilt angle A2

over the entire length of the ski.

  Of course, in these two previous embodiments, the angles A1 and A2 vary as a function of the position considered along the ski, and their variation is of the same type as that of the embodiment of FIGS. 1 to 8: in the central zone, the angle admits a maximum value, and decreases as we approach the ends of the

ski.

  There are shown in Figures 16 to 18 some other variants of the longitudinal profile of the box according to the invention. Thus, in FIG. 16, the lateral resistance walls 222 and 223 are convex, for example in the portion of a cylinder. In FIG. 17, the lateral resistance walls 222 and 223 are concave. In FIG. 18, the upper resistance blade 221 is concave, while in the previous embodiments it was substantially flat and

  simply arched longitudinally upwards.

  In the embodiments which have been represented, the lateral resistance walls 222 and 223 are substantially parallel to the outer lateral faces 4 and 3 respectively of the ski, and, in certain embodiments, they constitute by themselves said said

  external side faces. The lateral resistance walls, incli-

  variable inclination, then combine the effects of modifica-

  tion of the behavior of the box and the ski for sliding and hanging, and of the behavior of the ski linked to the shape of the faces

side of the ski.

  The ski according to the present invention can be manufactured by traditional means, for example by a process described in the document

FR-A-985 174.

  However, the ski according to the invention can also be manufactured

  qué according to a process described in the French patent application n ..

  filed the same day by the plaintiff.

  The present invention is not limited to the embodiments.

  which have been explicitly described, but it includes the various

  variants and generalizations contained in the field of claims

the following.

he

Claims (9)

CLAIMS 1l - Ski for evolution on snow, the body of which comprises, substantially over its entire length, a core (10) surrounded by a mechanical resistance box, the box comprising an upper resistance blade (221) secured to two resistance walls lateral (222, 223) themselves secured to a lower resistance blade (34), the lateral resistance walls (222, 223) forming with the lower resistance blade (34) an angle of inclination (A), characterized in that one at least of the lateral resistance walls has a variable angle of inclination A along the ski body as a function of the longitudinal position considered, giving the ski body properties of mechanical resistance that vary according to the longitudinal position considered.   2 - Ski according to claim 1, characterized in that the angle of inclination A in the central zone of the ski is greater than the angle of inclination A in the vicinity of at least one of the ends of the zone ski contact.   3 - Ski according to any one of claims 1 or 2,   characterized in that the angle of inclination A in the central zone of the ski is greater than the angle of inclination A in the vicinity of the line of front contact (6) of the ski.   4 - Ski according to any one of claims 1 to 3,   characterized in that the angle of inclination A in the central zone of the ski is greater than the angle of inclination A in the vicinity of the line of rear contact (7) of the ski.   - Ski according to any one of claims 1 to 4,   characterized in that the lateral resistance walls (222, 223) are symmetrical to each other with respect to a longitudinal vertical plane median (I-I) of skiing.   6 - Ski according to any one of claims 1 to 4,   characterized in that the lateral resistance walls (222, 223) are asymmetrical.   7 - Ski according to any one of claims 1 to 6,   characterized in that the angle of inclination A is at most equal to 90 'on the entire length of the ski body.   8 - Ski according to any one of claims 1 to 7,   characterized in that the angle of inclination A is substantially equal to   in the central ski area.   9 - Ski according to any one of claims 1 to 8,   characterized in that, in the vicinity of at least one of the two lines of   contact (6, 7), the angle of inclination A is less than 10.   10 - Ski according to any one of claims 1 to 9,   characterized in that the angle of inclination A varies continuously the along the body of the ski.   11 - Ski according to any one of claims 1 to 10,   characterized in that the lateral resistance walls (222, 223) are substantially parallel to the corresponding external lateral faces (4, 3) skiing.