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1. WO2013156837 - SKI, GRINDING WHEEL FOR MACHINING SAID SKI AND MACHINE COMPRISING SAID GRINDING WHEEL

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

SKI, GRINDING WHEEL FOR MACHINING SAID SKI AND MACHINE

COMPRISING SAID GRINDING WHEEL

DESCRIPTION

The present invention concerns a ski provided with a sole with grooves that favour the sliding movement of the ski on snow.

The present invention also concerns a grinding wheel to be used to produce said grooves on a ski, as well as a machine using said grinding wheel.

It is known that while a ski slides on snow friction is generated between the sole and the snow, which causes the snow itself to melt, with the consequent formation of a thin water film that increases resistance to the advance movement of the ski.

In order to avoid the problem described above, it is customary to make a plurality of grooves on the sliding surface of the sole, the depth of said grooves being typically less than 200 microns and, in any case, less than 1 mm, and said grooves being mainly developed according to the longitudinal direction of development of the ski and allowing said water film to be drained off.

It is known that the shape and arrangement of said grooves is of fundamental importance for the performance of the ski and that each individual pattern of said grooves can be more suitable than others for a specific condition of the snow surface.

In order to allow different types of processing to be performed depending on the conditions of the snow, the use of programmable machines is known, which allow any groove pattern to be obtained on the ski rapidly and automatically.

The machines of the known type comprise a cylindrical grinding wheel provided with a plurality of ridges on its lateral surface.

The grinding wheel is arranged with its cylindrical surface in contact with the sliding surface of the ski and is set rotating, so that the ridges provided on the grinding wheel impress corresponding grooves in the sliding surface.

During the processing cycle, the ski is advanced parallel to its longitudinal direction, so that said grooves are impressed on the entire length of the ski. To vary the groove pattern, the machines of the known type comprise a motor-driven tool operated automatically through a program that can be set by the user when necessary or be already set.

Said tool impresses a series of grooves on the cylindrical surface of the

grinding wheel, said grooves being generally helical and with different pitches and being intertwined so as to form said ridges.

It is the object of the present invention to provide a machine for processing the sliding surface of a ski that allows a wider variety of groove patterns to be obtained compared to those obtainable with the machines of the known type. In particular, it is the object of the present invention to obtain grooves that, compared to those obtainable with the machines of the known type, make it possible to achieve better ski performance in specific conditions of the snow surface.

The objects mentioned above are achieved by a machine for processing a ski according to claim 1.

The said objects are also achieved by a grinding wheel for said machine, produced in accordance with claim 7.

The said objects are also achieved by a ski in accordance with claim 8.

Further detail characteristics of the various aspects of the invention described above are specified in the corresponding dependent claims.

Advantageously, the machine that is the subject of the invention makes it possible to obtain new groove patterns that can adapt better than the known ones to specific conditions of the snow surface.

The said objects and advantages, together with others that will be explained below, are illustrated in the description of a preferred embodiment of the invention that is provided by way of non-limiting example with reference to the attached drawings, wherein:

- Figure 1 schematically shows a side view of the machine for processing a ski according to the invention;

- Figure 2 shows a detail of the ski of the invention.

The ski that is the subject of the present invention, indicated by 1 in Figure 2, comprises a sole that defines a sliding surface 2 intended to come in contact with the snow.

Said sliding surface 2 is provided with a plurality of mutually parallel grooves 13, mainly developed according to the longitudinal direction of the ski 1.

The length of said grooves 13 is preferably but not necessarily shorter than one tenth of the length of the ski, and even more preferably it is shorter than one hundredth of said length.

Furthermore, the respective maximum depths of the grooves 13 are preferably

less than 1 mm, and even more preferably they are included between 1 micron and 200 microns.

According to the invention, said grooves 13 have respective maximum depths that are different from one another.

5 The applicant of the present invention discovered that, surprisingly, the presence of grooves 13 with different maximum depths makes it possible to improve the sliding capacity of the ski 1.

Preferably, among said grooves 13 it is possible to identify a first plurality of grooves 13 having respective maximum depths equal to one another and l o a second plurality of grooves 13 having respective maximum depths equal to one another but different from the maximum depths of said first plurality of grooves 13.

Even more preferably, it is possible to identify a third plurality of grooves 13 having respective maximum depths equal to one another but different from the 15 maximum depths of said first and second plurality of grooves 13.

Preferably, the maximum depth of the grooves 13 varies according to a direction W orthogonal to the longitudinal direction of development of the ski 1 , meaning according to the width of the ski 1.

Preferably, said variation is such that the maximum depth of the grooves 13 0 increases proceeding from the centre area of the sliding surface 2 towards the sides 2a, 2b of the same, according to said orthogonal direction W.

To obtain grooves 13 with a pattern of the type described above, a machine 3, schematically shown in Figure 1 , is preferably used, which comprises a grinding wheel 4 provided with a cylindrical surface 5 that defines a longitudinal 5 axis X.

The cylindrical surface 5 of the grinding wheel 4 comprises a plurality of ridges mainly developed according to corresponding helical trajectories around the longitudinal axis X of the grinding wheel 4.

In particular, said ridges have a maximum height that varies according to their

30 position along said longitudinal axis X.

The grinding wheel 4 is associated with first power means, not shown herein but known per se, suited to set it rotating around its longitudinal axis X.

The machine 3 also comprises a guide unit 7 for the ski 1, configured so as to move the latter according to an advance direction Y parallel to the longitudinal 5 direction of development of the ski 1 and incident, preferably at right angles, on the longitudinal axis X of the grinding wheel 4.

In particular, during the movement, the guide unit 7 maintains the sliding surface 2 of the ski 1 in contact with the cylindrical surface 5 of the grinding wheel 4.

5 In this way, when the ski 1 is moved, the ridges present on the grinding wheel 4 that is rotating impress on the sliding surface 2 grooves 13 whose pattern depends on the pattern of said ridges.

The machine 3 also comprises a tool 8, for example a diamond tool, suited to be placed in contact with the grinding wheel 4 that is rotating, so as to produce l o a groove on the cylindrical surface 5 of the grinding wheel 4 itself.

The tool 8 is associated with second power means, not illustrated herein but known per se, suited to move it according to a direction of movement Z parallel to the longitudinal axis X of the grinding wheel 4.

There is also a logic control unit, not illustrated herein but known per se, 15 configured so as to operate said first power means and second power means in such a way as to move the tool 8 according to the direction of movement Z based on the rotation angle of the grinding wheel 4 around its longitudinal axis

In particular, said logic control unit makes it possible to impress helical grooves 0 on the cylindrical surface 5 of the grinding wheel 4.

The logic control unit is furthermore configured so that it operates the second power means in such a way as to vary the processing depth of the tool 8 according to the rotation angle of the grinding wheel 4.

The machine 3 described above thus makes it possible to move the tool 8 in 5 such a way as to obtain on the grinding wheel 4 an helical groove with varying depth along its trajectory.

Obviously, this makes it possible to combine a plurality of grooves so as to obtain, on the cylindrical surface 5 of the grinding wheel 4, corresponding ridges with different heights.

0 Therefore, said ridges allow corresponding grooves 13 with different depths to be impressed on the ski 1.

Preferably, the logic control unit is configured so as to increase the processing depth as the tool 8 proceeds from the mid plane of the grinding wheel 4, defined as the plane of symmetry of the grinding wheel 4 perpendicular to the 5 longitudinal axis X, towards each side of the latter.

In this way, it is possible to obtain corresponding ridges whose maximum height increases towards the sides of the grinding wheel 4.

A grinding wheel 4 configured as described above allows grooves 13 to be made on the ski 1 whose depth is smaller at the level of the centre area of the sliding surface 2 and increases proceeding from said centre area towards the sides 2a, 2b of the sliding surface 2.

Preferably, the logic control unit is also configured so as to move the tool 8 in such a way as to make two or more grooves with its trajectory, said grooves being positioned side by side and partially overlapping so as to define a single groove whose width exceeds that of each single groove.

Advantageously, the execution of said multiple grooves makes it possible to obtain grooves whose width exceeds the width of the tool 8.

Consequently, to advantage, it is possible to obtain grooves with different widths using a single tool 8.

Preferably, the first power means and the second power means of the machine 3 are electric motors of the "brushless" type that, advantageously, ensure very high precision of movement.

In fact, the inside of brushless motors is provided with a magnetic encoder that makes it possible to detect the angular position of the respective rotors with higher precision compared to the precision that can be obtained from other types of encoder.

It can thus be understood that the higher precision in determining the angular position of the motors allows the logic control unit to coordinate their movements with a consequently higher precision, so as to obtain a trajectory of the tool 8 that is more precise than that obtainable with the machines of the known type.

The guide unit 7 of the ski 1 preferably comprises a driving wheel 10 facing the grinding wheel 4 and suited to be positioned against the ski 1 on the opposite side with respect to the sliding surface 2.

In particular, the driving wheel 10 is associated with third power means, not illustrated herein but known per se, suited to set it rotating in such a way as to move the ski 1 along the advance direction Y at a predefined speed corresponding to the tangential speed of the driving wheel 10.

The logic control unit is preferably configured in such a way as to operate said third power means at a speed that varies according to the rotation angle of the driving wheel 10, meaning depending on the position of the ski 1 with respect to the grinding wheel 4.

Advantageously, the possibility to vary said speed makes it possible to modify the pattern of the grooves 13 along the longitudinal direction of the ski 1, 5 further increasing the range of the obtainable patterns.

In particular, a higher speed in moving the ski 1 makes it possible to expand the grooves 13 in the longitudinal direction of the ski 1 , and vice versa.

Preferably, the driving wheel 10 is also associated with thrust means, not illustrated herein but known per se, suited to thrust it against the ski 1 with a l o variable thrust force that can also be controlled by the logic control unit.

In particular, the logic control unit is configured so as to operate said thrust means in such a way that the thrust force generated by them varies according to the rotation angle of the driving wheel 10.

Advantageously, the variation in the thrust force as described above makes it 15 possible to modify the depth of the grooves 13 in the longitudinal direction of the ski 1, maintaining the ratio between the respective depths crosswise with respect to the ski 1 substantially unchanged.

The machine 3 described above preferably comprises also storage means, not illustrated herein but known per se, suited to store a predefined program 0 and/or a program set by the user when necessary.

In this last case, the logic control unit is associated with programming means that are accessible to the user and allow the latter to set the various operating parameters of the machine 3.

Said operating parameters may comprise, among others, the rotation speed of 5 the grinding wheel 4 respectively during execution of the grooves and during processing of the ski, the translation speed of the tool 8 during processing of the grinding wheel 4 and according to the angular position of the latter, and the processing depth of the tool 8 according to the angular position of the grinding wheel 4.

0 Preferably, said programming means are also configured so as to allow the user to set also the parameters regarding the driving wheel 10, in particular its speed and thrust force, according to the angular position of the driving wheel 10.

The machine 3 preferably comprises also simulation means configured so 5 as to create an image of the grooves 13 that can be obtained with a given

selected program and to display said image on a screen.

In practice, in order to process a ski 1 , first of all it is necessary to prepare the grinding wheel 4, creating the required ridges.

If the grinding wheel 4 features ridges corresponding to a previous processing cycle, these are removed using the tool 8, which is moved and placed in contact with the grinding wheel 4 while this is rotating, in such a way as to remove the surface layer of the grinding wheel 4 together with the old ridges. Successively, the grinding wheel 4 is processed by the tool 8 based on one of the programs already stored in the machine 3, or based on a program implemented by the user at that moment using said programming means.

To do this, the logic control unit sets the grinding wheel 4 rotating at the speed set in the program and moves the tool 8 in such a way as to make the grooves on the cylindrical surface 5 according to the set trajectories and depths.

The grinding wheel 4 is generally provided with a plurality of grooves having different pitches, so that they intersect one another.

Once the grinding wheel 4 has been prepared, it is possible to use the machine 3 to process the ski 1.

More precisely, the ski 1 is arranged with the sliding surface 2 facing the grinding wheel 4 and with the driving wheel 10 resting on the opposite surface. At this point, the grinding wheel 4 and the driving wheel 10 are both set rotating, at respective predefined rotation speeds that are generally different from each other.

The movement of the driving wheel 10 makes the ski 1 advance along its longitudinal direction, keeping it in contact with the cylindrical surface 5 of the grinding wheel 4 that is rotating, so that the latter impresses the grooves 13 on the sliding surface 2 of the ski 1 according to the programmed pattern.

The above clearly shows that the invention achieves all the set objects.

In particular, the possibility to make ridges with varying height on the grinding wheel makes the machine of the invention more flexible than analogous machines of the known type.

Furthermore, the grooves with different depths that can be obtained with the machine that is the subject of the invention make it possible to obtain a ski with better sliding properties compared to those obtainable from machines of the known type.

Further variant embodiments of the machine, of the grinding wheel and of the

ski of the invention, although not described herein and not illustrated in the drawings, must all be considered protected by the present patent, provided that they fall within the scope of the following claims.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the protection of each element identified by way of example by such reference signs.