Abstract:
A shoe contains an adjustable space for the foot and several fluidically connected chambers. In order to adjust the space for the foot, the flowability of a magnetorheological liquid can be influenced by at least one device generating a magnetic field thereby adjusting the space for the foot resulting in a better fitting of the shoe.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a continuing application, under 35 U.S.C. § 120, of copending international application No. PCT/AT2006/000329, filed Aug. 3, 2006, which designated the United States; this application also claims the priority, under 35 U.S.C. § 119, of Austrian patent application No. A 1309/2005, filed Aug. 3, 2005; the prior applications are herewith incorporated by reference in their entirety. 
     
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
       [0002]    The invention relates to a shoe, in particular a ski boot, having a variable foot area and having a magnetorheological liquid, whose capability to flow can be influenced for varying the foot area by at least one device for producing a magnetic field. The invention also relates to skiing equipment, having a ski with a ski binding, a ski pole and a shoe such as this. 
         [0003]    A shoe for matching to a foot shape is described for example, in published, non-prosecuted German patent application DE 19 62 632 A. The closed shoe can be matched to the foot shape by virtue of the flexibility of a cushion, such that the compound that can flow is moved from areas in which the pressure on the foot is greater into areas in which the pressure is lower. Since the aim is for the shoe to surround the foot as firmly as possible, in order to prevent relative movements between the shoe and the foot, the compound that can flow must move only slowly. The compound that can flow is therefore a high-viscosity liquid or has low viscosity and is forced through flow-restricting constrictions when being moved. 
         [0004]    In order to allow the shoe to react over the course of time to changes in the volume of the foot as well after its adaptation when being fitted, it is possible, for example, for the height of the inner sole to be adjustable or, in particular, for a supply container for the liquid to be provided in the sole, which is linked such that flow can pass to the cushion or the cushion via lines, such that the amount of liquid contained in the cushion can be varied. Control and actuating devices that are required for this purpose are preferably likewise accommodated in the sole of the shoe. 
         [0005]    International patent publication WO 00/47072 discloses the use of an inner sole or an insert sole with a continuous cushion or a cushion which is provided only in the toe or heel area in a ski boot or roller skating shoe, which cushion contains a liquid whose capability to flow is varied under the influence of a magnetic field. At least a part of a device for producing the magnetic field is for this purpose also preferably disposed adjacent to or in the shoe. In the case of a ski boot, parts of the device may also be provided, for example, on the ski binding. 
         [0006]    Magnetorheological liquids (MRL) are liquids that are distinguished by an increase in their apparent viscosity under the influence of a magnetic field. Without the influence of a field, they generally have a low viscosity and, under the influence of a field, they could be considered to be solid bodies provided that the field-strength-dependent limiting shear stress is not exceeded. 
         [0007]    They are formed of a basic liquid and solid particles which are ferromagnetic. The proportion by volume of the solid particles is in this case between 20% and 60%. Chains with branches of greater or lesser strength of these solid particles are responsible for the increase in the viscosity. These are held together by magnetic forces between the particles. Shearing of the fluid first of all results in strain and, as the shear stresses become higher, in the chains being torn open. Continuous recombination of the broken chain pieces ensures that the increased viscosity is in principle maintained under the influence of a field, even at relatively high shear rates. Experiments have shown that a liquid dynamic viscosity of more than 10 Pa·s is advantageous for use in shoes. 
         [0008]    Both liquids have already been known for a relatively long time and are used, for example, in shock absorbers and torque converters. Recently, a magnetorheological liquid has also become known in the form of a gel. 
         [0009]    In principle, electrorhealogical liquids can also be used for this purpose. Electrorhealogical liquids have a lower relative density, but require a higher voltage to change the capability to flow that, for example, can be applied to the liquid via electrodes. Since, in the case of shoes, higher voltages are dependent on corresponding, independent energy sources, magnetorheological liquids are considerably more suitable for these and other mobile applications. 
         [0010]    The use of magnetorheological liquids would ideally allow occasional or else frequent, rapid matching of the foot area to the instantaneous shape of the foot, foot retention and foot position, with the foot being firmly surrounded by the shoe, held to the desired extent, and without any pressure points after each matching process, again. However, the solution known from WO 00/47042 does not achieve this since it is not possible to achieve that degree of variability that is required for matching to the relatively complicated geometry and three-dimensional shape of a foot. Furthermore, magnetorheological liquids have a rather high relative density because of the ferromagnetic particles, so that only a limited amount of liquid can be used, even for ski boots. 
       BRIEF SUMMARY OF THE INVENTION 
       [0011]    It is accordingly an object of the invention to provide a shoe, in particular a ski boot, and skiing equipment that overcomes the above-mentioned disadvantages of the prior art devices of this general type. 
         [0012]    With the foregoing and other objects in view there is provided, in accordance with the invention, a shoe. The shoe contains a variable foot area, at least one device for producing a magnetic field, deformable chambers with flow links connecting the deformable chambers to each other, and a magnetorheological liquid having a capability to flow being influenced for varying the variable foot area by the at least one device for producing the magnetic field. 
         [0013]    The described problem is solved according to the invention in that a plurality of flow-linked chambers are provided instead of a single chamber surrounding the major parts of the foot. Since intermediate spaces remain even with a relatively tight arrangement, the total volume of the chambers is in any case less than that of a single large chamber. However, somewhat larger intermediate spaces are preferably provided, and the chambers are combined into units which, for example, are similar to bubble-wrap sheets used for packing purposes. 
         [0014]    A plurality of small chambers not only make it possible to reduce the weight but also allow a preferred embodiment in which the magnetic fields are applied only to the lines or to the flow links, such that only that magnetorheological liquid which is located in the flow links is solidified, then impeding the movement of the liquid which is enclosed in the chambers. If the flow links are of adequate length, a further preferred embodiment provides for the magnetorheological liquid in each flow link to be enclosed by two sealing elements which can move in the flow link, and to be separated from a different compound, which can flow, in the chambers. 
         [0015]    The liquid enclosed in the chambers can in this embodiment be lighter and, for example, may be a basic magnetorheological liquid without magnetic solid particles or water, thus not only making it possible to save weight but also costs, since magnetorheological liquids are relatively expensive. The liquid enclosed in the chambers may also contain lightweight filling particles, for example spheres composed of plastic or the like, which can additionally also contribute to better thermal insulation. 
         [0016]    In a further preferred embodiment, a constriction is formed in the flow link and is disposed approximately centrally in the magnetic field, so that the magnetorheological liquid solidifies to form a plug that surrounds the constriction on both sides, in an interlocking form. The fixing in the flow direction could also be improved by making the inner wall of the flow link uneven, rough, or providing it with projections. In order to make use of the magnetic forces and the energy available with as high an efficiency as possible, the important factor is for the magnetic field lines to pass through the flow links at right angles to the direction in which the magnetorheological liquid flows. 
         [0017]    There are various options for practical implementation. The chambers may be connected in series, which is to say a line extends from a supply container through the chambers back to the supply container. The flow links to be connected are located between the chambers or the supply container and the first and last chambers. This requires a greater number of devices for producing magnetic fields, preferably adjacent to each flow link. Permanent magnets are more suitable for this purpose, so that there is no need for electrical lines. However, electromagnets may, of course, also be used. 
         [0018]    Another option is for the design to be configured such that one line originates from the supply container per chamber, and each line or flow link has an associated device for producing a magnetic field. This embodiment can be implemented quite advantageously with permanent magnets or electromagnets if all of the flow links to be influenced are provided, for example, in an area close to the supply container. 
         [0019]    If flow links can be influenced in the same way in groups, then they can be subjected to common magnetic fields. When the flow links are disposed in series, for example, elongated permanent magnets may surround all the flow links which are connected in a row. If the lines run individually to each chamber, then the joint common influence, as described above, can be produced in an area close to the supply container, in which a plurality or all of the lines are located parallel alongside one another, as long as at least one device for producing a magnetic field is provided there. By way of example, this may once again have an elongated permanent magnet that surrounds the lines. A common electromagnet can, of course, also be used in this case. 
         [0020]    If permanent magnets are provided, then the magnetorheological liquid is located in a constant magnetic field, and the flow links that are subject to the magnetic field are solidified. 
         [0021]    In order now to change the foot area as required, a first embodiment provides for the permanent magnet to be disposed such that it can be moved relative to the flow link in the shoe in order to attenuate or deactivate the magnetic field. In order to attenuate or deactivate the magnetic field, thus allowing compensation between the variable-shaped chambers and the supply container, the permanent magnet in a cylindrical embodiment in the form of a rod can be rotated such that the magnetic field lines no longer run at right angles through the flow link, or are extracted from a pocket of the shoe. As soon as the foot area has been matched, the permanent magnets are rotated back, or are inserted again. 
         [0022]    Another preferred option is for the permanent magnet to have an associated moveable magnetic shield in order to attenuate or deactivate its magnetic field. The effect that can be achieved in this way is similar, but the shield which, for example, is in the form of a plate, is rotated or removed, instead of the permanent magnet. 
         [0023]    One alternative embodiment provides for each permanent magnet to have an associated switchable electromagnet that neutralizes, deactivates or reverses the magnetic field of the permanent magnet so that electrical energy is required only for the brief opening of the flow links that is necessary to reshape the chambers. 
         [0024]    If sufficient amounts of electrical energy can be made available, then, in a further embodiment, only at least one electromagnet may be provided, which can not only be switched on and off but whose magnetic field intensity can preferably be varied, in particular continuously. When the aim is to match the ski boot, the electromagnet is switched off, so that the magnetorheological liquid can move. Once the ideal fitting shape has been achieved, the electromagnet is energized again. 
         [0025]    The supply container preferably likewise represents a chamber that, in particular, is accommodated in the sole of the shoe and may have an associated pump or other pressure generating device. 
         [0026]    A generator that converts vibration movements may be provided as the source for electrical energy. A first embodiment of a generator such as this produces a rather low voltage, in accordance with Faraday&#39;s induction law, which is suitable for influencing magnetorheological liquids by moving a conductor backwards and forwards relative to a magnetic field. Vibration occurs continuously, particularly when skiing, thus in this way providing more than an adequate amount of electrical energy for a permanently energized electromagnet. 
         [0027]    Each of the described “vibration generators” preferably has associated control electronics and an associated energy store, for example a rechargeable battery or a capacitor. The generator for producing the electrical energy may, in particular, be disposed adjacent to the rear face or adjacent to the upper face of the ski boot, angled upwards. Particularly when skiing, the continuous vibration results in excess electrical energy, which can also in this case be used to heat the shoe or to feed other loads. 
         [0028]    In another embodiment, a chamber can be provided as a supply container for the liquid and is connected by a feed pump via at least one line to the chamber or to the chambers, so that the pressure in each chamber can also be set and varied, and can also preferably be varied in the various chambers independently of one another. Each chamber may in this case also have an associated sensor. 
         [0029]    The control electronics, the energy store, the supply container, the feed pump etc., are preferably accommodated in the sole of the ski boot. User-specific data and skiing-style-specific data can be stored in a data memory so that an appropriate setting for the fitting of the ski boot to the foot can be predetermined. Signals emitted from the sensors can also be used for automatic matching to external conditions, such as the piste state, skiing conditions, and skiing circumstances etc. 
         [0030]    Alternatively, however, it is also possible to provide for at least some of these apparatuses to be provided in the ski, in the ski binding or in some other part of the skiing equipment. This makes it possible, for example, for the size of the foot area to be reduced later and not immediately during or after putting on the shoe. This allows the shoe to be used for comfortable walking despite being fitted such that it is stable and fixed while skiing. 
         [0031]    A closure flap or the like, for example, can be provided in the heel area or in the area at the front of the foot in order to put the ski boot on. When the closure flap is closed, the foot can be firmly fitted in the shoe for example by operating a conventional buckle, a rotating knob or the like, thus increasing the pressure in the chambers before application of the magnetic fields. In this case, electromagnets can be switched on by a further buckle or the like which can be operated subsequently. If the ski boot contains control electronics, then these electronics can, of course, also be programmed in such a way that the closing of the shoe first of all increases the pressure in the chambers, and then energizes the electromagnets. 
         [0032]    Other features which are considered as characteristic for the invention are set forth in the appended claims. 
         [0033]    Although the invention is illustrated and described herein as embodied in a shoe, in particular a ski boot, and skiing equipment, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
         [0034]    The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0035]      FIGS. 1 and 2  are diagrammatic, sectional views through two different exemplary embodiments of a ski boot according to the invention; 
           [0036]      FIG. 3  is a diagrammatic, sectional view through an ankle part of a third embodiment of a ski boot; 
           [0037]      FIG. 4  is a diagrammatic, sectional view taken along the line IV-IV shown in  FIG. 3 ; 
           [0038]      FIG. 5  is a schematic illustration of a mechanically switchable permanent magnet; 
           [0039]      FIG. 6  is a schematic illustration of an electrically switchable permanent magnet; 
           [0040]      FIG. 7  is a diagrammatic, perspective view of a flow link between two chambers with an associated electromagnet; 
           [0041]      FIG. 8  is a schematic illustration of a configuration of a plurality of chambers which can be influenced in parallel; 
           [0042]      FIG. 9  is a schematic view of a plurality of chambers which can be influenced in parallel; 
           [0043]      FIG. 10  is an enlarged view of a flow link with a constriction; 
           [0044]      FIG. 11  is a schematic illustration of a configuration of a moveable shield; 
           [0045]      FIG. 12  is a schematic illustration of a variant in which the magnetorheological liquid is provided only in the flow link; and 
           [0046]      FIG. 13  is a flowchart for use of a ski boot according to the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0047]    Referring now to the figures of the drawing in detail and first, particularly, to  FIG. 1  thereof, there is shown a ski boot according to the invention that preferably has an outer shoe with a relatively thick sole, on which front and rear binding elements act in order to produce the connection to the ski. Internally, the ski boot may be provided additionally with cushioning  5 , composed of foam in selected areas, for example adjacent to the rear closure flap  2 , which can be rotated about an axis  19  as shown in  FIG. 1 . A plurality of chambers  3 , for example between 10 and 20, are provided at least in pressure-sensitive areas and are filled with a magnetorheological liquid which preferably has a dynamic viscosity of at least 10 Pa·s and solidifies when a magnetic field is applied. It is also possible, but not necessary, for the entire foot area to be enclosed by chambers  3 . 
         [0048]      FIGS. 3 and 4  schematically illustrate devices  30  for producing a magnetic field, which devices are in the form of permanent magnets  8 , with flow links  7  being located in their magnetic fields between the chambers  3 . The chambers are disposed in a plurality of rings one above the other in the ankle part of the boot, so that the closure flap  2  that is provided at the front in this embodiment also has chambers  3 . The permanent magnets  8  are inserted in pockets that extend to the upper edge of the ankle part of the boot, so that they can be rotated or pulled out upwards in order to vary the foot area  1  and to deform the chambers  3 . As soon as the ski boot has been matched to the foot again, the permanent magnets  8  can be rotated back again or pushed in again, as a result of which the magnetorheological liquid circulating in the flow links  7  solidifies again. Alternatively, as is shown schematically in  FIG. 11 , a magnetic shield  32  can be inserted between the permanent magnets  8  and the flow links  7 . Magnetorheological liquid contained in the chambers  3  remains liquid, but cannot move because of the small volume of the chamber  3 , which is blocked by the flow links  7 . As shown in  FIG. 10 , the flow links may each have a constriction  29 , so that the solidified magnetorheological liquid forms a plug which surrounds the constriction in an interlocking manner. Alternatively or additionally, the inner wall of the flow links  7  may also be uneven or rough. By way of example, the pressure in the chambers  3  can be set conveniently by at least one rotary knob that is not shown, and may also be retained differently, despite subsequent matching with the flow links being influenced in an appropriately variable manner. 
         [0049]    The chambers  3  may also be composed of a flexible material, which may also be elastic, and, as is illustrated schematically in  FIG. 9 , may be provided on one side of a mounting panel  28  or the like. The chambers  3  may be identical or else, as is indicated in  FIG. 9 , may have different shapes. The lines  6  and the flow links  7  which are not shown here, are disposed on the other side of the mounting panel  28  and are passed to the chambers  3  through a respective hole. The chambers  3  may also be disposed one above the other in a plurality of, in particular, offset, layers. 
         [0050]    Let us now return to  FIGS. 1 and 2 , in which the only schematically indicated chambers  3  are associated with the side and front of the foot area  1 , and possibly also with the rear, and/or are in the inner sole  4 . The chambers  3  are connected to one another and to a supply container  14  via lines  6 , which are disposed together with other elements  11 ,  12 ,  13 ,  15  and  16  in the sole, which is normally thick in the case of ski boots. If required, the supply container  14  may itself represent a further chamber. The lines  6  have associated electromagnets, which are not shown, for example in a similar manner to the permanent magnets  8  shown in  FIGS. 3 and 4 , by which it is possible to vary the capability of the magnetorheological liquid to flow, in the described manner. 
         [0051]    An electric motor  11  is also schematically indicated in  FIG. 1  and, via a drive shaft  13 , operates a piston of a pump  12 , by which the magnetorheological liquid can be forced out of the supply container  14  into the chamber  3  in order to match the foot area  1  to the foot, at least on initial use. When used subsequently, for example if the foot is fitting loosely, there are pressure points or it is uncomfortable, the pressure can be reduced or else increased by the pump  12 . The motor  11  has associated control electronics  15  and an associated energy store  16 , for example a capacitor or a rechargeable battery. By way of example, the pressure can be monitored by at least one sensor, whose signals are processed by the control electronics, thus allowing the ski boot to be automatically matched to the foot. 
         [0052]    As  FIG. 1  shows, the electrical energy which is required for the electromagnets and other electrical loads, for example shoe heating, can also be produced in the ski boot if, for example, a generator  9  which converts vibration movement is provided adjacent to the rear face, with the vibration causing a permanent magnet and an induction coil to be moved relative to one another. The embodiment illustrated schematically in  FIG. 1  shows a generator  9  that has two permanent magnets  18  which move linearly with respect to sprung end stops and have two associated induction coils. The electricity that is generated flows via a line  10  to the energy store  16  and to the motor  11  in the shoe sole. 
         [0053]    In  FIG. 2 , which does not show the elements  11  to  16  in the shoe sole in detail, an inclination adjustment device for the ankle part of the boot is disposed adjacent to the front of the boot, with damping in the form of a piston-cylinder unit  17 , which likewise contains a magnetorheological liquid, which is likewise connected via the line  6  to the supply container  14  in the sole, and likewise has an associated device for producing the corresponding field. 
         [0054]      FIG. 5  shows, schematically, a configuration of the permanent magnet  8 , which is disposed within iron caps  24 , which form two magnet poles, such that it can rotate. In the illustrated position, the magnetic field lines  27  of the magnetic field pass through the area close to the poles. The entire arrangement is associated with a flow link  7  between two chambers  3  such that it is located within the magnetic field lines  27 . When the permanent magnet  8  is rotated through 90°, for example by an external rotary knob, the magnetic field is moved, and the magnetic field lines run within the two iron caps  24 . The flow link  7  in the area close to the poles is therefore located outside the magnetic field, and the magnetorheological liquid that has been solidified in this are can flow again, so that the liquid can move. A plurality of flow links  7  disposed one behind the other can easily be connected in together if the permanent magnet  8  is in the form of a rod. 
         [0055]      FIG. 6  shows, schematically, the flow link  7  with a rectangular cross section, which is likewise under the influence of the permanent magnet  8 . The magnetic flux is represented by the magnetic field lines  27 . The two iron caps  24  have a first pole pair  26  and, on the opposite side, a second pole pair. One of the two iron caps  24  has an associated winding  25 . Electrical energy can now be supplied in such a way that the magnetic field produced by the permanent magnet  8  is neutralized, and the magnetic flux no longer runs over the first pole pair  26  but over the second pole pair, averted from the flow link  7 . The magnetorheological liquid that has been solidified therein can flow again. This embodiment requires little energy, since such energy need be supplied only to deactivate the permanent magnet  8 . 
         [0056]      FIG. 7  shows a cut-open oblique view of the flow link  7  and an associated electromagnet  20 . The line  6  that contains the magnetorheological liquid is, for example provided with a cruciform iron core  21 , leaving four flow channels free. A winding  23  surrounds the line  6 , and is itself surrounded by an iron casing  22 . When a voltage is applied to the winding  23 , then the magnetic field solidifies the magnetorheological liquid, and flow is no longer possible. Once the current flow is switched off, flow can pass through the link  7  again. 
         [0057]      FIG. 8  shows, schematically, a parallel arrangement of chambers  3 , to each of which a line  6  is passed from the supply container  14 . The supply container  14  has an associated pump  12 , which is operated by the motor  11 . Also, instead of the motor  11  as the power source, the piston of the pump  12  may have an associated schematically shown compression spring or some other pressure generator, possibly also a hand pump or the like. Close to the supply container, the flow links  7 , on which the already described constrictions  29  ( FIG. 10 ) are preferably provided, have an associated common device  30 , for example in the form shown in  FIG. 11 , in order to produce a magnetic field. On the opposite side of the flow links  7  to the permanent magnets  8 , which flow links  7  preferably have an essentially rectangular or, as shown, trapezoidal cross-sectional shape,  FIG. 11  shows a layer  36  composed of a magnetic material, for example an iron plate or an iron sheet, a magnetic film or the like, so that the magnetic field lines  27  are closed, and the flow links  7  pass through at right angles to the flow direction. The strength of the field or of the permanent magnet or magnets  8  can now be varied by inserting a shield  32  between the flow links  7  and the permanent magnets  8 , which can be done by hand or, for example, by a motor drive. This is illustrated on the right-hand side of  FIG. 11 , in which the outermost magnetic field lines  27  have already been deflected by the shield and no longer pass through the flow link  7 . In simple terms, the magnetorheological liquid is liquid in the area of the shielded magnetic field lines  27 , and is solidified in the area of the unshielded magnetic field lines. The movement of the shield  32  from the illustrated position leads either to complete opening of the flow link  7  (insertion in the direction of the arrow) or to its complete closure (removal in the opposite direction). 
         [0058]    In the embodiment shown in  FIG. 12 , the magnetorheological liquid is restricted to the area of the flow link  7 , and is sealed in the line  6  at both ends by a sealing element  31  against the medium which is used in the other areas and, in particular, costs less and/or is lighter. 
         [0059]    If equalization is intended to take place between the supply container  14  and the chamber  3 , for example in order to dissipate any overpressure which may occur in the chamber  3  as a result of swelling of the foot, then the magnetic field of the device  30  is attenuated or cancelled out, and the excess medium is forced into the line  6 . The magnetorheological liquid can be moved to the right, together with the sealing elements  31 . The appropriate amount of the medium in the line  6  leading to the supply container is pumped back into the supply container. As soon as equalization has been achieved, the magnetic field is produced again, and the magnetorheological liquid in the flow link  7  solidifies. The new state is thus ensured. 
         [0060]      FIG. 13  shows a block diagram of the major steps for use of the ski boot according to the invention, starting with the opening of the rear flap. The ski boot is then fitted and the rear flap closed and locked. In this case, the locking mechanism (latching in) or a sensor (switch) ensures secure closure. For example bolts which latch in at the side, Velcro strip around the ski boot, buckle, snap-action closure, etc. The user-specific settings are then made, specifically corresponding to the weight, the skiing style (beginner, normal, sports, cross country), the piste conditions etc. A “start” push button is then operated, resulting in the inner shoe being filled with magnetorheological liquid, so that the inner shoe rests over its entire area on the foot. Operation of the on/off switch opens the devices for production of the magnetic field (MRL valves) and the pump is activated, feeding the magnetorheological liquid from the reservoir into the inner shoe. In the process, the pressure downstream from the pump is measured by a pressure sensor, and is increased until the desired pressure (user-specific setting) is reached. The valves are then automatically closed. Subsequently, the ski boot is then matched again, automatically following a time interval, or on operation by the user (and, for example, the pressure is kept constant). 
         [0061]    The comfort when wearing a ski boot according to the invention is considerably improved since the internal shape of the foot area  1  can be varied and can be matched to the foot directly, at least when required, not only by convenient operation by removal and insertion of the permanent magnets, by adjustment of a rotary knob etc., but also by using electrical energy for operation.