FR3116700A1 - Device for thermoforming ski boots - Google Patents

Abstract

The present invention relates to a device for thermoforming inner liners (C) and/or shells for ski boots, said device comprising means for heating a fluid associated with means for blowing said fluid, the means for blowing said fluid being connected to a duct arranged inside at least one arm (1a, 1b), a section (11b) of which is introduced into the liner or the shell via its stem (T) in order to diffuse the said heated fluid therein via at least an exhaust orifice (10) made through the wall of said section, characterized in that said arm (1a, 1b) is provided with a peripheral sleeve (2) providing thermal insulation between the rod (T) of the liner (C) or the shell and the blowing means, and ensuring an even distribution of the heat inside the liner and/or the shell. Figure of the abstract: Fig. 1

Description

Device for thermoforming ski boots

The invention relates to a device intended for the thermoforming of ski or snowboard boots, and in particular for the thermoforming of the inner lining of these boots.

The invention relates, more particularly, to an improvement of the traditional devices ensuring the heating of a shoe or a liner, molded beforehand and/or assembled in a standard way in the factory, and comprising at least one thermally deformable material ( called thermoformable), such as a thermoplastic polymer (for example polyurethane, etc.) or a foam (for example based on PU, EVA, polyethylene, etc.), the final shape of which must be adapted to the foot of the user for convenience.

The heating of the liner or the shoe is generally carried out either in an oven, or by means of a device comprising, in particular, thermal means for heating a fluid (such as air or steam), coupled to blowing means ensuring the injection of a flow of this preheated fluid inside the liner or the shoe.

This current of hot fluid thus makes it possible, in a first step, to soften the constituent material of the liner or that of the shoe, immediately before, in a second step, its fitting by the user gives it a shape matching that of his foot. Subsequent cooling causes the material to freeze so that the liner or shoe can then retain this shape over time.

At the same time, the adjustment of the temperature of the fluid delivered by such a device makes it possible to use it also for drying, sterilizing or disinfecting the interior lining, in particular, when the ski boots are intended for rental.

More specifically, the known thermoforming devices comprise at least one arm supported by a box containing the fluid blowing means. This arm is provided with an internal duct for ejecting this fluid provided with thermal means ensuring the heating of this fluid and emerging outside through its side wall via exhaust orifices to diffuse the hot fluid (gas , liquids, aerosols, etc. in the inner volume of the liner and soften its material with a view to its subsequent shaping.

Patent FR 2 739 760 describes a device for thermoforming the inner linings of ski boots comprising a nozzle ensuring the distribution of hot air in the lining. This device is provided with means for positioning the nozzle comprising a seat able to receive the upper of the shoe and a stop limiting the introduction of the nozzle inside the lining. The shoe is thus positioned in an inverted position on the nozzle, via its upper.

However, the effectiveness of such a device does not prove to be satisfactory because there appears to be a significant leak of hot air between the periphery of the rod of the lining slipper and the side wall of the nozzle due to the fact that the external diameter of the nozzle is usually narrower than the inside diameter of the rod. Moreover, the hot air escapes all the more towards the bottom of the device, opposite the upper part of the liner, because it is at this very place that the opening of the liner or the shoe intended for the insertion of the foot is the most important.

This results in a loss of heat energy which results in an often insufficient capacity for deformation of the malleable or thermoformable material of the liner or of the shell or more generally of the shoe, so that its subsequent shaping by fitting can allow it to fit the user's foot perfectly.

In addition, due to the positioning of the liner and/or the shell on the nozzle, this air leak causes disturbances in the heat flow inside and discontinuities in the heating temperature in their various parts and, in particular, between their upper part and their lower part. Such a device therefore does not make it possible to heat the thermoformable material of the liner or of the shoe correctly and sufficiently so that it can quickly and uniformly reach its softening temperature.

In this context, the aim of the present invention is to solve the technical problems posed by the prior embodiments by proposing a thermoforming device making it possible to eliminate, or at least significantly reduce, the leaks of hot fluid between the arm and the liner or shoe, which are likely to cause a lowering of the heating temperature.

This object is achieved according to the invention by means of a device for thermoforming inner liners or shells for ski boots, said device comprising means for heating a fluid associated with means for blowing said fluid, the means for blowing of said fluid being connected to a duct formed inside at least one arm, a section of which is introduced into the liner or shoe via its upper in order to diffuse said heated fluid therein via at least one exhaust orifice formed through it of the wall of said section, characterized in that said arm is provided with a peripheral sleeve providing thermal insulation between the upper of the liner and the blowing means and a homogeneous distribution of the heat inside the liner or the shell.

According to an advantageous characteristic, the sleeve covers at least the upper part of the upper of the liner.

According to a first variant embodiment of the device of the invention, the arm consists of at least one tube, the end of which is closed and curved to match the bottom of the liner.

Preferably, this arm comprises two telescopic tubes so that its total length can be adjusted to the size of the liner.

According to a specific variant embodiment of the invention, the sleeve is made of a flexible material that is permeable to air and has, where appropriate, pores.

According to a specific variant, the sleeve is provided on its downstream edge with a drawstring intended to adjust the dimensions of its opening around the upper of the liner or that of the shoe.

According to another characteristic, the blowing means are enclosed in a box supporting said arm and to which the upstream edge of the sleeve is fixed.

According to yet another characteristic, the means for heating the fluid are housed in the arm.

According to another variant, the thermoforming device comprises two arms adapted and intended, respectively, for a right foot liner and a left foot liner, each of the arms being provided with a peripheral sleeve.

Preferably, the sleeve is made of a thermally insulating textile material and in the form of a bellows.

According to yet another variant, the thermoforming device further comprises a removable cover intended to cover the liner.

Preferably, the cover is provided with an electrical resistance.

According to another characteristic of the device of the invention, the wall of the sleeve comprises pores with a diameter of between 0.5 and 5 mm, preferably between 0.5 and 3 mm.

Another object of the invention is a use of the device defined above for the thermoforming of inner liners or shells of ski boots or even snowboard boots, characterized in that the heated fluid is air.

According to a characteristic of the specific use of the invention, the blowing means and the heating means are adjusted to obtain an air temperature of between 50° C. and 80° C. in the liner (C) or the shell .

Thanks to the sleeve, the thermal insulation of the thermoforming device is reinforced and, due to the reduction of heat losses, the temperature of the fluid diffused by the arm inside the liner remains higher, which guarantees rapid, effective softening. , uniform and durable of its constituent material.

This results in better malleability of the thermoformable material of the liner or of the ski boot, during hot fitting, leading to a conformation that is better adjusted to the foot of the user and thus contributing, at the same time, to greater comfort later and to better athletic performance.

In addition, the device of the invention allows energy savings because the temperature of the air from the heating means can be significantly reduced without degrading the optimum temperature within the thermoformable material of the liner or the shoe shell. .

Other characteristics and advantages of the invention will become apparent on reading the description which follows, with reference to the appended figures detailed below.

shows a front view of an embodiment of the thermoforming device of the invention.

shows a front view of a variant embodiment of the device for thermoforming the .

represents a detail view of the device of the .

shows a perspective view of one embodiment of the sleeve of the device of the invention.

is a front view of the device of the represented in a specific mode of use of the invention.

is a graph representing the temperature variations Y in the upper part of the liner as a function of time X, respectively, without a sleeve and with a sleeve according to the invention.

For greater clarity, identical or similar elements are identified by identical reference signs in all the figures.

Naturally, the embodiments illustrated by the figures presented above are only given by way of non-limiting examples. It is explicitly provided that these different modes and variants can be combined together to offer others.

The device of the invention is illustrated in the in the context of use for thermoforming the liners C of ski boots, but the invention is not limited to this use. The thermoforming device could also be used for thermoforming any other type of winter sports shoe, such as shells Q of ski boots (as illustrated by the ), snowboard boots, or Nordic ski boots.

The represents an embodiment of the device of the invention which is illustrated here in the context of the thermoforming of inner liners C for ski boots. These liners are generally manufactured and profiled in a standard way in the factory by molding the upper T of the liner, at least one layer of which comprises a thermally deformable or thermoformable material.

Conventionally, the slipper C has a lower part C1 attached to a sole S and which completely surrounds the foot, covering, in particular, the instep and going up to the level of the ankle. The liner C also has a more open upper part C2, intended to surround the lower leg, which comprises two side flaps positioned forwards, close to a front tongue L fixed to the lower part C1 at the level of the neck of the foot. This assembly forms the upper T of the liner.

The wall of the liner has an at least partially traditional structure, formed by three layers (not visible in the figures): an inner layer forming the inner lining, intended to be in contact with the foot and the leg, and a more rigid outer layer , intended to provide hold to the liner. These two layers delimit an interior volume in which a cushioning material in the form of foam is positioned, to form a third layer of intermediate cushioning. In general, there is also found in the tongue L of the liner, positioned mainly in the upper part C2 of the liner, a superposition of these same layers, with at least one padding material.

The material constituting the intermediate padding layer is generally thermoformable and can be, for example, formed from a thermoplastic foam based on PU, EVA or even polyethylene. Thus, when it is heated to its deformation temperature, preferably between 60 and 100°C, and once the foot is inserted into the liner, the thermoformable padding material of the intermediate layer of the liner takes the shape of the foot of the shoe. user in a stable and durable way, in particular by compressing in the prominent areas of the foot.

As a side note, all the materials used in the structure of the liner are not necessarily thermoformable and only certain areas or parts may comprise a thermoformable material. This is particularly the case for the areas of the upper T facing the malleoli, the metatarsals, or even the tibia (for the tongue).

Thus, the interior volume of the upper T of the liner is adapted to the foot of the user. The finished liner is then placed, optionally removable, in a rigid ski boot shell Q.

Furthermore, it is also possible to provide that the shaping of the liner is not final and is therefore reversible. In this case, the profile of the upper T of the liner can be modified again and adapted to the shape of another foot, even if the liner has already been used and/or thermoformed beforehand or remodeled following a deforming first use. . It is then sufficient to remove the liner from the shell Q or to position the liner directly in its shell on the thermoforming device, to carry out a new shaping.

Traditionally, such a thermoforming device comprises thermal means, for example one or more electrical resistors (not shown) ensuring the heating of a fluid, generally and preferably, air, associated with blowing means ( not shown) and therefore pressurizing this fluid. For ergonomic reasons, the air suction and blowing means are preferably enclosed in a box B also containing members K for adjusting and controlling these means (visible on the front of the box on the ).

These blowing means are connected, outside of box B, to a duct provided inside an arm which, in the embodiment illustrated by FIGS. 1 and 2, extends vertically from from the upper face of box B.

The thermal means for heating the air are either housed in the box B by being directly coupled to the blowing means, or housed in the arms 1a, 1b. In the latter case, these heating means preferably consist of electrical resistors and are integrated, for example, in the wall of the inner duct of the arms.

In order to heat and soften the thermoformable material of the liner C and, in particular, the intermediate padding layers of its wall, at least the upper section 11b of this arm, which is intended to be introduced into the liner, is provided with 10 heated air exhaust ports. These orifices 10 are provided through the wall of the conduit and on its periphery and diffuse, inside the liner C, the air pressurized by the blowing means and heated by the thermal means.

Preferably, the arm 1a, 1b consists of at least one tube, the end 12 of which is closed and curved to match the shape of the liner. The curvature of the end 12 of the tube is adapted to the bend formed at the junction of the lower and upper parts of the liner, so as to be able to penetrate easily to the bottom of the liner and to ensure the wedging of the liner on the arm. The slipper C is thus placed, upside down, via its upper T on the arm that it covers and on which it rests in balance and/or by jamming.

In the specific embodiment shown in the , each arm 1a, 1b comprises two telescopic tubes 11a, 11b, the total length of which can optionally be adjusted according to the size of the liner.

It so happens that with traditional devices, there generally remains a large space between the inner contours of the upper T of the liner C and the outer wall of the arm, in particular in the upper part of the liner, at the place where the opening for the insertion of the foot is the most important. This is how a significant fraction of the heated air tends to escape, generating heat losses that are detrimental to the temperature rise of the liner and to the desired change in the state of the thermoformable material constituting the liner. .

Typically, when the thermal means are integrated into the wall of the arms 1a, 1b, the air temperature is around 160° C. at the outlet end of the arms 1a, 1b, around 140° C. -height of the arms and of the order of 90° C. in the lower part of the arms. In a preferential use of the device of the invention, the members K for adjusting and controlling the air blowing means are adjusted to obtain this temperature of 160° C. at the end of the arms.

The invention aims to solve this technical problem by seeking, at the same time, to ensure the thermal insulation of the connection zone between the liner C and/or the shell Q and the sections of the arm ensuring the diffusion of hot air , and to better confine the space defined at the base of the arm.

The objective of the invention is therefore to better distribute the heat energy available inside the liner C (or the shell Q), that is to say, in a more homogeneous way, with a view to limiting the losses of heat in the opening zones of the liner, in order to obtain an appropriate temperature over its entire internal surface and within its thermoformable material. This substantially homogeneous distribution of calorific energy makes it possible to guarantee the same degree of softening in all the interior zones of the liner or the shell and a shaping that then perfectly matches the user's foot.

To this end, the thermoforming device according to the invention is provided with a thermal insulation sleeve 2 mounted peripherally around the arm 1a, 1b and intended to ensure the conservation of heat by retaining the hot air between the stem T of the liner C and the blowing means. This sleeve 2 thus extends from the upper face of the box B as far as the lateral sides of the liner, enclosing the upper T, as illustrated by FIGS. 1 and 2.

Still according to the invention, the sleeve at least partially covers the upper part C2 of the liner C, here in the inverted position on the device. The upper end of the sleeve stops substantially before the malleolus area. As a variant, the sleeve could cover the entire upper part C2 of the liner. The sleeve could also extend from the upper part to the lower part C1.

The sleeve 2 is made of a flexible material such as a thermally insulating textile material and is here in the form of a generally cylindrical bellows, open at its two upper and lower ends so as to have a capacity for relative elongation. However, this sleeve is not necessarily waterproof in itself.

Indeed, the material constituting the sleeve could be, for example, Lycra (registered trademark), polyester, polyamide or waterproof-breathable materials of the Gore-Tex type (registered trademark). The material of the sleeve could also be elastic, to better adapt to different sizes of liner or shoe.

According to yet another variant, the material constituting the sleeve can be pierced or have pores to allow at least a fraction of the hot air blown to escape and thus be permeable to air. The material of the sleeve may, for example, comprise pores with a diameter of between 0.5 and 5 mm, preferably between 0.5 and 3 mm, and these pores may be spaced apart by a distance of between 1 and 10 mm, preferably between 4 and 8 mm.

Depending on the variant in which the fabric is this time pierced with holes whose diameter is greater than that of the pores, these holes could have a diameter of the order of a centimeter. This configuration thus makes it possible to avoid any overpressure phenomenon which could damage the sleeve 2, while maintaining, in its interior volume, a flow of hot air making it possible to reach the thermoforming temperatures necessary for the modification of the shape of the constituent materials. of the slipper. In this case, the wall of the sleeve could be sealed and the exhaust orifices 10 of the arms 1a, 1b would then be positioned close to the upper and/or lower open ends of the sleeve 2, or even differently on the periphery of the sleeve so as to allow a small fraction of air to pass.

The downstream edge 22 of the sleeve 2 (encompassing the sides of the liner C) is provided with a drawstring 22a intended to adjust the dimensions of its upper opening around the upper T of the liner (or the shell Q of the shoe and in particular its collar. If necessary, the upstream edge 21 will also be provided with a drawstring 21a ( ), if necessary. As a variant, any other device for tightening or adjusting the sleeve 2 around the upper T of the liner or the shell Q of the shoe can be envisaged, such as, for example, hook-and-loop strips (of the Velcro type - registered trademark ), or an elastic tie of adjustable length.

Thus, all the airflow delivered by the blowing means and heated by the thermal means is channeled and retained by the sleeve 2 into the interior volume of the liner C by minimizing heat losses. Thanks to this arrangement, the temperature of the air inside the sleeve 2 is relatively stable and is maintained uniformly and constantly around 135°C. However, this temperature, which is lower than the temperature of 160°C of the air blown from the heating means, takes into account heat losses due to the structure of the device. This temperature of 135°C is that of the ambient air inside the sleeve and the liner and not that which prevails at the level of the layers of the wall of the liner, in its thickness.

Indeed, although the air heated by the device can exceed the temperature of 160°C, the optimum temperature Y to be reached in the thickness of the liner for a durable shaping of the thermoformable material is lower and between 50° C and 80°C, preferably between 60 and 70°C. However, it is provided that this temperature does not exceed 80°C in order not to damage the liner and to avoid burning the wearer of the liner when inserting his foot into the upper for shaping. Since the device of the invention makes it possible to reach this temperature Y within the thermoformable material of the liner, in general after a period X of between 6 and 10 minutes, preferably after approximately 8 minutes, the liner will be kept in place on the machine during this time.

Although the temperature of the air injected into the liner or shoe by the device of the invention is adjustable by the user (with a preferential value of 160° C.), it could be envisaged to dispense with this setting and to predefine the value of 160° C. directly in the factory as the value of standard operation of the device.

In order to maintain a constant temperature at the outlet of the arms, a temperature sensor may be provided. Indeed, the heating means do not operate continuously, and are activated when the value measured by the sensor at the arm outlet drops below the desired operating temperature, here 160°C.

It would also be possible, for each user, to opt for different settings of the device. Indeed, by heating more strongly, it is in theory possible to reach the temperature Y of 60°C more quickly in the thickness of the liner. Alternatively, by heating less, but longer, it is also possible to reach 60°C in the thickness of the liner. The operating parameters of the device could also be adjusted according to the materials (nature, thickness, density, etc.) making up the liner and/or the shell of the shoe.

As illustrated by the graph of the , thanks to the sleeve 2 of the invention, the optimum temperature Y of 50° C. to 80° C. of the upper part of the liner and, in particular, that of the tongue L (curve Y1) is reached in a period X of 8 minutes whereas it is difficult to reach even after 10 minutes of operation in the absence of a sleeve (curve Y0).

With regard to shells, the thermoforming temperature of their thermoformable constituent material is generally less than 100°C. Indeed, this plastic material generally includes additives which make it possible to lower its melting temperature below 100°C and, more precisely, between 60°C and 100°C. These temperatures can therefore be easily obtained with the thermoforming device of the invention under conditions similar to those used for the liners.

The upstream edge 21 of the sleeve 2 located on the outlet side of the blowing means is, for its part, fixed in a leaktight manner on the upper face of the box B, for example, by gluing.

As a variant, the upstream edge 21 of the sleeve 2 could be linked by rivet or screwing to the upper face of the box B. In this case, heated air can escape from the sleeve through this connection zone, but the means of heating and the blowing means will then be adjusted so that the temperature of the heated air penetrating inside the liner remains sufficient to obtain correct softening of its thermoformable constituent material.

In order to be able to carry out simultaneous thermoforming operations for the respective liners of the same pair of shoes, the thermoforming device comprises two arms 1a, 1b adapted and intended, respectively, for a right foot liner and a left foot liner, each of the arms 1a, 1b being provided with a peripheral sleeve 2. In this case, the respective curvatures of the end sections 12 of the two arms can be reversed.

According to a variant embodiment illustrated by FIGS. 2 and 3, the thermoforming device of the invention further comprises a removable cover 3 intended to cover at least partially the lower part C1 of the liner C, in particular at the level of the areas thermoformables of the liner, such as the malleolus area and the metatarsal area.

This cover 3 is made of a flexible and thermally insulating material and is provided with a set of tightening members 31, for example, straps ( ) allowing it to be adapted to different sizes of slippers. According to this variant embodiment, the cover 3 can extend from and above the sleeve 2 to cover the lower part C1 of the liner. This cover could also form a double thickness with the wall of the sleeve by being placed either inside the sleeve or outside.

However, the cover 3 does not come to cover the sole S of the liner, which is generally assembled by gluing to its upper T, because too intense heating at the level of this sole could detach it or damage it.

Preferably, the cover 3, represented separately on the , is provided with an electrical resistor, integrated in its wall and connected via a cable 32 to an integrated power supply in the box B. This additional arrangement thus makes it possible to reinforce the thermal insulation by reducing the losses through the wall of the liner while improving heating and thermoforming from the outside of the liner. It is thus possible to obtain a double heating action, on the one hand, from the inside of the liner by the hot air coming from the arms, and on the other hand, from the outside by contact with the heating blanket 3 .

Although the invention which has been described above applies mainly to the thermoforming of a single liner, previously extracted from a shoe shell, it is possible, without departing from the scope of the invention, to apply it also the thermoforming of an liner in situ in the shell. However, and as illustrated by the , the invention can also be applied to the thermoforming of a bare shell made of thermoformable material or internally coated with a layer of thermoformable packing.

Claims (16)

Device for thermoforming inner liners (C) and/or shells for ski boots, said device comprising means for heating a fluid associated with means for blowing said fluid, the means for blowing said fluid being connected to a arranged inside at least one arm (1a, 1b) of which a section (11b) is introduced into the liner or the shell via its upper (T) in order to diffuse the said heated fluid therein via at least one exhaust orifice (10) provided through the wall of said section, characterized in that said arm (1a, 1b) is provided with a peripheral sleeve (2) providing thermal insulation between the upper (T) of the liner (C) or of the shell and the blowing means, and ensuring even distribution of the heat inside the liner and/or the shell. Thermoforming device according to Claim 1, characterized in that the sleeve (2) covers at least the upper part of the upper (T) of the liner (C). Thermoforming device according to one of the preceding claims, characterized in that the said arm (1a, 1b) consists of at least one tube, the end (12) of which is closed and curved to match the bottom of the liner. Thermoforming device according to one of the preceding claims, characterized in that said arm comprises two telescopic tubes (11a, 11b) so that its total length can be adjusted to the size of the liner. Thermoforming device according to one of the preceding claims, characterized in that the said sleeve (2) is made of a flexible material permeable to air. Thermoforming device according to the preceding claim, characterized in that the said flexible material has pores. Thermoforming device according to one of the preceding claims, characterized in that the said sleeve (2) is provided on its downstream edge (22) with a drawstring (22a) intended to adjust the dimensions of its opening around the stem (T) of the liner (C) or that of the shell. Thermoforming device according to one of the preceding claims, characterized in that the blowing means are enclosed in a box (B) supporting the said arm (1a, 1b) and on which is fixed the upstream edge (21) of the sleeve ( 2). Thermoforming device according to one of the preceding claims, characterized in that the means for heating the fluid are housed in the said arm (1a, 1b). Thermoforming device according to one of the preceding claims, characterized in that it comprises two arms (1a, 1b) adapted and intended, respectively, for heating a right foot shoe and a left foot shoe, each arms being provided with a peripheral sleeve (2). Thermoforming device according to one of the preceding claims, characterized in that the said sleeve is made of a thermally insulating textile material and in the form of a bellows. Thermoforming device according to one of the preceding claims, characterized in that it further comprises a removable cover (3) intended to cover the liner. Thermoforming device according to the preceding claim, characterized in that said cover (3) is provided with an electrical resistance. Thermoforming device according to one of the preceding claims, characterized in that the wall of the sleeve comprises pores with a diameter of between 0.5 and 5 mm, preferably between 0.5 and 3 mm. Use of the device according to one of the preceding claims for the thermoforming of inner liners and/or shells of ski boots or snowboard boots, characterized in that the said heated fluid is air. Use of the device according to the preceding claim, characterized in that the said blowing means and the said heating means are adjusted to obtain an air temperature (Y) of between 50°C and 80°C in the liner (C) or shell.