[0001] In the skiing world, particular attention is paid to the research and creation of
equipment with soles able to produce the maximum speed on the snow. For this reason,
in recent years, soles have been produced in sinterized Polyethylene with a variable
density and mixed with particular additives like graphite powder, fluorine and other
materials and mixtures which remain industrial secrets. The soles are therefore formed
uniformly of a single material or mixture across their width, length and thickness.
The soles produced in this way are then assembled as skis by the producer.
[0002] It is well known that the speed of the ski depends on the friction (mechanical and
electromagnetic) which it produces in the sliding phase. The ski slides on the snow
in two conditions:
- when a film of water forms between the snow and the sole, giving rise to lubricated
sliding,
- or when the layer of water is not present, causing dry sliding.
[0003] The faster ski is obviously the one that slides on the film of water. This layer
of water which acts as a lubricant between the sole and the snow is not uniform but
instead has a thickness that gradually increases from the tip to the tail of the ski.
Nevertheless, in conditions of high humidity and snow temperature, the excessive quantity
of water that forms can cause the so called suction phenomenon, hence compromising
the speed of the ski. The object is hence to improve the sliding of the ski both when
the veil of water is excessive or when the veil of water is not present
[0004] The basic idea started with the fact that the ski slides on snow thanks "to the friction"
it produces, even if this seems at first a paradox.
[0005] When the ski slides on the snow it produces friction that creates heat, which in
turn causes the fusion of the snow crystals that, in this way, lubricate the sole
with small particles of water and so allow the ski to slide. All this obviously happens
with a correct equilibrium at a molecular level.
[0006] When, however, the ski slides on very cold snow the friction of the sole by itself
is not able to melt the snow crystals suffciently. The insertion of wedges of another
material, (in the central front part of the sole), whose coefficient of friction is
better than that of the sole (e.g. Elastomerics), activates the above described mechanism.
In the mechanical field or in other fields where friction is found, this type of phenomenon
doesn't exist - skis represent the only such example.
[0007] When, instead, the ski must slide on '"warm" wet snows, the presence of excess water
creates a cohesion between the surface of the sole and that of the snow, thereby reducing
the speed of the ski. In this case the insertion of wedges of P.T.F.E. (Teflon), a
fluorine based compound that is one of the most waterproof and non-stick polymers
which exist in commerce today, placed in the rear central part of the ski, improves
the smoothness that contributes to the expulsion of excess water.
1. The drainage of excess water (in case of lubricated sliding).
[0008] The scope of the present find is to favour the expulsion of excess water which forms
between the sole and the snow by the insertion of wedges of water repellent material
PTFE (Teflon), in the most critical points of the ski, similar or of another type
as illustrated in Fig. (9)F. These inserts can be placed along the entire length of
the sole of the ski (from the tip to the tail of the ski). In particular in cross-country
skis these inserts will be placed preferably in the rear area of the ski starting
from the point where the heel of the boot is found towards the tail where the veil
of water is greater and in the front part of the ski starting from the area which
goes from the point where the tip of the foot is found towards the spatola of the
ski. These inserts must be of such a shape that they will convey the excess water
towards the sides of the ski expelling it to the outside. The number of inserts, their
form, their thickness, the type of material used and their placing are all to be considered
as part of this present find as illustrated in Fig. N° (4) (5).
2. The formation of water between the sole and snow (in case of dry sliding).
[0009] When instead the conditions of the snow are such that the quantity of water between
the sole and the snow is absent or insufficient, the ski moves on the snow deforming
and/or shattering the "uneveness" present on the snow surface greatly reducing the
sliding of the ski. The scope of the present find is that of resolving the problem
by inserting materials that create friction, for example rubber or other materials,
in strategic points of the sole. The heat generated by these inserts during the sliding
phase of the ski favour the formation of a film of water between the sole and the
snow as illustrated in Fig. (1)C. The number of these friction inserts must be such
as to produce the right heating during the sliding phase so as to obtain an "energy
exchange": the creation of friction produces heat that in turn produces a veil of
water that acts as a lubricant for the sole thereby increasing the sliding. This,
in turn, increases the speed of the ski. Naturally the friction inserts must be of
a costituent material (polimeric plastics, elastomerics, rubber and others) and must
be of a dimension, type of surface, outline, number and placement on the ski, to offer
the most advantages possible in respect to the friction caused by the inserts themselves
as illustrated in Fig. N° (1) (2) (3). With regards to cross country skis, these inserts
will be placed preferably in the front area of the ski starting from the balancing
point of the ski itself towards the tip and from the zone between the heel of the
boot and the tail of the ski. These inserts can be of various materials, forms, widths
and multiple thicknesses and even in imaginitive shapes that are however designed
to optimize the system, and are all considered inclusive of the present find.
[0010] Also included in this find, is a sole for skis obtained by multiple extrusion or
coupling, by means of gluing or other systems, on the whole length, or part of it,
with antirepellent plastic materials like PTFE (Teflon) or a mixture of elastomerics
and other materials with a chemical composition that is different to the sole itself
as shown in Fig. N° (6) (7).
[0011] In the past certain cross-country ski producers made skis with soft rubber inserts
placed in the central zone of the sole and of the ski, the scope of which was to prevent
the ski from sliding backwards in uphill. This was based on the same principles of
ski waxes (klister or stick): that the snow crystals can penetrate anchoring themselves
in the rubber and so permitting ascent without slipping back. This, therefore, has
nothing to do with our find. Regular inserts in the sole of skis, made of the same
material as the sole, but of a contrasting color, transparent or opaque, are often
made. These are used to highlight the aaanufacturer's logo or name. This type of insert,
also, has nothing to do with this find
[0012] The inserts, regarding both the systems for the formation of water particles (veil
of water) or for the expulsion of excess water Fig. (9) C-F, can be placed on the
inside of the sole as per example in Fig. D1, or they can occupy the entire length
of the sole itself as in the example in Fig. D2. Furthermore, the inserts can be made
of two or more different materials mounted between them with the scope of improving
or augmenting the performance as in Fig. (8). Even in this case all the above mentioned
premises are to be considered in regards to the form, the materials and the placement.
1. SOLES FOR SKIS with particular inserts that cause or the drainage of, or the formation
of a veil of water between the sole and the snow characterized by the fact that for the drainage of the water the special inserts (D2) which are placed
in the sole (F) are of waterproof material type PTFE (Teflon) or of other materials
unlike the material of the sole itself.
2. SOLES FOR SKIS with particular inserts that cause or the drainage of, or the formation
of a veil of water between the sole and the snow characterized by the fact that for the drainage of the water the inserts have a form that causes the
expulsion of the water towards the external part of the ski. Fig. N° (4) (5).
3. SOLES FOR SKIS with particular inserts that cause or the drainage of or the formation
of a veil of water between the sole and the snow characterized by the fact that for the drainage of the water the inserts have a chemical composition
which drives back the excess water.
4. SOLES FOR SKIS with particular inserts that cause or the drainage of, or the formation
of a veil of water between the sole and the snow characterized by the fact that for the drainage of the water the inserts can be one, or more than
one, and positioned on the entire surface of the sole or part of it.
5. SOLES FOR SKIS with particular inserts that cause or the drainage of, or the formation
of a veil of water between the sole and the snow characterized by the fact that for the drainage of the water the soles can be obtained by multiple
extrusion, coupling, gluing or by other systems for the entire length or part of it,
with water-repellent plastic materials generally a type of PTFE (Teflon) or however
of materials with diverse chemical composition (E) with respect to the sole itself(G)
as shown in Fig. N° (6) (7).
6. SOLES FOR SKIS with particular inserts that cause or the drainage of, or the formation
of a veil of water between the sole and the snow characterized by the fact that for the drainage of the water the inserts can have varying shapes,
thicknesses and forms, the most diverse, even the most imaginative, but all orientated
to the optimising of the conditions of the system. Fig. N° (4) (5).
7. SOLES FOR SKIS with particular inserts that cause or the drainage of or the formation
of a veil of water between the sole and the snow characterized by the fact that to create the formation of a veil of water the special inserts (D1)
placed in the sole (C) must be of materials that produce friction such as: elastomeric
or polimeric plastics and other materials of diverse composition with respect to the
sole itself
8. SOLES FOR SKIS with particular inserts that cause or the drainage of, or the formation
of a veil of water between the sole and the snow characterized by the fact that to create the formation of a veil of water between the sole and the
snow the inserts must be of a chemical composition that produces friction and therefore
heat and consequently is capable of melting the snow crystals.
9. SOLES FOR SKIS with particular inserts that cause or the drainage of, or the formation
of a veil of water between the sole and the snow characterized by the fact that to create the formation of a veil of water between the sole and the
snow the inserts can have varying shapes and forms, the most diverse, even the most
imaginative, but all orientated to the optimising of the conditions of the system.
Fig. N° (1) (2) (3) (8).
10. SOLES FOR SKIS with particular inserts that cause or the drainage of, or the formation
of a veil of water between the sole and the snow characterized by the fact that to create the formation of a veil of water between the sole and the
snow the inserts can be one, or more than one, and positioned on the entire surface
of the sole of the ski or on part of it.
11. SOLES FOR SKIS with particular inserts that cause or the drainage of, or the formation
of a veil of water between the sole and the snow characterized by the fact that to create the formation of a veil of water the soles can be obtained
by multiple extrusion, coupling, glueing or other systems for it's entire length or
part of it, with mixes of elastomeric or polimeric plastics or however of materials
with diverse chemical compositions (E) with respect to the sole itself (G) as in Fig.
N° (6)(7),
12. SOLES FOR SKIS with particular inserts that cause or the drainage of, or the formation
of a veil of water between the sole and the snow characterized by the fact that the inserts can be obtained by coupling two, or more, different materials
set between them and inserted in the sole H as in Fig. (8).