WO2019172760A1

WO2019172760A1 - Midsole for a shoe, shoe, and system

Info

Publication number: WO2019172760A1
Application number: PCT/NL2019/050145
Authority: WO
Inventors: Gert Willem MONDRIA
Original assignee: Mondria Gert Willem
Priority date: 2018-03-07
Filing date: 2019-03-07
Publication date: 2019-09-12
Also published as: NL2020547B1; EP3761825A1

Abstract

The invention relates to a midsole for a shoe, in particular a sports shoe. The midsole comprises a body arranged to be placed between an outsole and an insole of the shoe, wherein the body comprises a forefoot part that is arranged for positioning at a forefoot side of the shoe and a hind foot part that is arranged for positioning at a hind foot side of the shoe. In the midsole the forefoot part and hind foot part are mutually adjustable. The body is provided with unlockable fixation means which are arranged to releasably fix, in use, the forefoot part in relation to the hind foot part.

Description

Title: Midsole for a shoe, shoe, and system

The present invention relates to a midsole for a shoe, in particular a sports shoe, comprising a body that is arranged to be placed between an outsole and an insole of the shoe, which body comprises a forefoot part that is arranged to be positioned on a side of the forefoot of the shoe and a hind foot part that is arranged to be positioned on a side of the hind foot of the shoe, wherein the forefoot part is adjustable in relation to the hind foot part.

The present invention also relates to a shoe, in particular a sports shoe, comprising a shoe upper and an outsole, wherein a midsole is provided between the shoe upper and the outsole, which midsole comprises a body that is arranged for placement between the outsole of the shoe and an insole of the shoe, which body includes a forefoot part arranged for positioning on a forefoot side of the shoe and a hind foot part arranged for positioning on a hind foot side of the shoe, the forefoot part being adjustable in relation to the hind foot part.

Furthermore, the present invention relates to a system for adjusting a stiffness of a midsole of a shoe.

Shoes often comprise a shoe upper that is designed to closingly fit around at least a foot of a user, and a sole attached to an underside of the shoe upper to support the foot while wearing the shoe. The sole of a shoe usually includes an outsole arranged to contact a surface on which the user is walking or running and an insole arranged to contact the foot of the wearer. A midsole can be applied in shoes, and in particular in sports shoes, to provide a degree of cushioning or stiffness to the sole as desired by the user, depending on the application of the shoe. For example, there are shoes with a relatively flexible midsole that give a high level of comfort to a user. Shoes with a relatively flexible midsole are, for example, suitable as endurance running shoes, in order to put as little load as possible on a foot on which the shoe is worn during a relatively long consecutive use of the shoe by a user. Conversely, shoes are also known in which the midsole has a higher stiffness. This makes such shoes more suitable for use in activities where relatively high forces have to be exerted by the feet on a surface, such as during short running distances or sprints. The known midsoles, both the flexible and more stiff version, usually assume a body that is arranged for placement between an outsole and an insole of the shoe, which body comprises a forefoot part that is arranged for positioning on a forefoot side of the shoe and a hind foot part that is arranged for positioning on a hind foot side of the shoe, wherein the forefoot part is adjustable in relation to the hind foot part. By a selection of material and/or thickness for the midsole, a degree of adjustability of the forefoot part in relation to the hind foot part, i.e. a stiffness of the sole as experienced by the user, can be chosen as desired. A drawback of the well-known midsoles, however, is that once chosen, a stiffness thereof during use is not adjustable. However, this may in fact be desirable for a user, for example when changing circumstances during use of the shoe require a different stiffness of the sole.

An aim of the present invention is therefore to provide a midsole that meets the drawback mentioned above. In particular, the invention has the aim to provide a midsole that can be adjusted in stiffness during use, and more specifically to provide a midsole that can be adjusted in stiffness during a sports activity. A further particular purpose of the present invention is to provide an intelligent midsole, in particular a midsole suitable for customization, i.e. adjustability as desired. It is also an aim of the present invention that the midsole provides a user with continuous maximum support in his/her personal movement during use, adapted to the personal preference in stiffness or flexibility, in order to optimise a user's performance. A further purpose of the present invention is to provide a shoe including such a midsole, in particular a sports shoe. A particular purpose of the present invention is to provide a system with a midsole or shoe with a midsole and a sensing device, wherein the sensing device is linked to the shoe or midsole in order to adjust a stiffness or flexibility of the midsole in dependence of a positioning of the shoe or midsole in relation to the sensing device registered by the sensing device.

To meet one or more of the intended purposes the invention provides a midsole or shoe as described in one or more of the claims contained herein.

One or more of the intended purposes is achieved in particular by the fact that the present invention provides a midsole or shoe of the kind described in the preamble, which is characterised in that the body is provided with unlockable fixation means which are arranged to be able to fix, in use, the forefoot part in relation to the hind foot part in an unlockable or releasable manner. By fixing the forefoot part in a position in relation to the hind foot part by means of the fixation means, a stiffening of the midsole is achieved. By unlocking of the fixation means, the forefoot part and the hind foot part of the midsole can be adjusted in relation to each other, which realises a flexibilisation of the midsole. Preferably the fixation means are adjustable by a user of the midsole or shoe during use so that the user of the shoe can adjust the midsole as desired from a relatively flexible state into a more rigid state, or vice versa, during use, for example during a sports activity. As such, the midsole offers a possibility upon application in a shoe to vary a stiffness thereof to a degree that the athlete wants, without significantly affecting a stability and comfort of the foot in the shoe.

In a preferred embodiment the midsole according to the present invention is characterized in that the body comprises at least two interlinked mutually hinging plates. The at least two interlinked plates provide a suitable durable support for the foot while the hinged coupling between the at least two plates allows a mutual hinging of the plates, which may facilitate the natural movement of the foot during use. In addition, the hinged coupling may provide a set hinge freedom or hinge resistance varying between a low hinge freedom or high hinge resistance for a rigid support and a high hinge freedom or low hinge resistance for a more flexible support.

In a further preferred embodiment, the midsole, according to the present invention, is characterised in that a first of the plates comprises the forefoot part and a second of the plates comprises the hind foot part. The hinged coupling between the forefoot part and the hind foot part of the at least two plates allows a hinge movement of the forefoot part in relation to the hind foot part, e.g. to allow during heel-to-toe gait of the foot when walking more or less freedom of movement of a forefoot part in relation to the hind foot part.

A particular embodiment of the midsole according to the present invention is characterised in that the plates are hinged coupled by means of a rotation axis. The rotation axis provides a reliable coupling between the plates to absorb the forces exerted on them during use of the midsole. In addition, the rotation axis provides sufficient low friction at hinging to prevent loss of energy and increase comfort during use. A further particular embodiment of the midsole according to the present invention has the characteristic that the forefoot part is rotatable around the rotation axis between a first position and at least a further position, and where the fixation means are arranged to fix the forefoot part in the first position or at least one further position. In this way, a stiffening of the midsole can be achieved in a desired position of the forefoot part in relation to the hind foot part. The foot parts of the midsole body are relatively rotatable relative to each other to rotate the rotation axis to provide a degree of flexibility of the midsole, and to fix it in a desired position to give a higher stiffness to the midsole in the fixed position.

In a further preferred embodiment, the midsole according to the present invention is characterized in that the fixation means include an electromagnetic source designed to carry an electromagnetic pulse through the rotation axis. In this way, the forefoot part can be fixed in the first position or at least one further position in relation to the hind foot part of the midsole by means of magnetic forces. This minimises the wear sensitivity of the fixation means.

In a further preferred embodiment the midsole has the characteristic, according to the present invention, that at least the forefoot part includes a pressure point zone provided with a pressure sensor that is configured to

communicate a registered pressure on the forefoot part to the fixation means. This allows the stiffness of the midsole to be adjusted in dependence of a measured pressure on the pressure point zone. The pressure sensor can communicate an increase in the pressure exerted by one foot on the forefoot part of the sole to the fixation means to fix the sole for a higher stiffness. Conversely, a lower pressure measured by the pressure sensor can be communicated to the fixation means in order to achieve a more flexible sole.

In a further preferred embodiment, the midsole is characterised in that the body is one-piece, wherein the forefoot part extends integrally from the hind foot part and wherein the forefoot part is adjustable in relation to the hind foot part along a weakening zone in the body. This allows for a continuous bending curve of the midsole that follows the contours of a foot during use. The weakening zone of the midsole can correspond with a hinging part of a foot, for example at a hinging zone of the foot. The body of one-piece is convenient to process in a shoe and can for instance during production of a shoe be connected to an outsole of the shoe, or instead be supplied separately from a shoe as a loose inlay body, wherein a user can place the midsole on the outsole inside a shoe upper.

In a further preferred embodiment the midsole has the characteristic that the weakening zone comprises one or more grooves in the body. As such an easy and inexpensive way to adjust the forefoot part in relation to the hind foot part is realized, wherein additionally by effective positioning of the one or more grooves a desired bending curve during use of the sole can be achieved, for example to promote an efficient heel-to-toe gait of the foot.

A particular embodiment of the midsole according to the present invention is characterised by the fact that the fixation means comprise a cavity in the body filled with a movable fluid, which cavity extends from the forefoot part towards the hind foot part through the weakening zone of the body. By applying pressure to the forefoot part, at least part of the fluid in the cavity can be pushed in the direction of the hind foot part where, due to increased fluid pressure in the cavity, it can achieve stiffening of the weakening zone. The cavity may also be provided with a movable element, such as a hydraulic pressure pin, which is displaced by the propulsion of the fluid to be positioned in the weakening zone as a locking to fix the forefoot part in relation to the hind foot part.

The midsole according to the present invention in a further preferred embodiment is characterised in that the fixation means comprise a flexing element extending between the forefoot part and the hind foot part in the body through the weakening zone, wherein the flexing element with respect to the body is rotatable around a rotation axis in a longitudinal direction of the midsole, wherein the flexing stiffness of the flexing element in use is dependent on the rotational orientation of the flexing element around the rotation axis in the midsole. By rotation of the flexing element the flexing stiffness of the flexing element and accordingly of the sole can be affected. For example, the flexing element can be made as a relatively flat element, for example a platedike body, in particular a leaf spring. The flexing element offers the least flexing resistance to the midsole when an orientation thereof in the midsole is with the flat sides thereof parallel to the outsole, whereas a flexing resistance thereof increases by rotation around the rotation axis with a maximum flexing resistance when an orientation of the flexing element in the midsole is with the flat sides perpendicular to the outsole. Accordingly by rotating the flexing element a quarter turn around the rotation axis a stiffer or instead a more flexible midsole can be realized.

A particular embodiment of the midsole according to the present invention is characterised by the fact that the bending element is provided with or coupled with an operatorelement for manually rotating the flexing element. The operator element can for example be a relatively simple turning button provided on an outer side of the shoe which turning button is connected to the flexing element to effectuate upon turning of the turning button a rotation of the flexing element in the midsole.

A further particular embodiment of the midsole according to the present invention is characterised by the fact that the hind foot part and the forefoot part are provided in a bottom layer of the body and that the body on an upper side comprises an elastic top layerwhich is coupled to the bottom layer. The elastic top layer provides a comfortable footbed for a user, and can move along with bending of the sole during use.

To further meet one or more of the intended aims, the invention also provides a system as described in one or more of the claims contained herein.

A further embodiment of the midsole according to the present invention has the characteristic that the fixation means are arranged to fixate a right foot part in relation to a left foot part of the midsole. In this way, in addition to a stiffening of the midsole in the longitudinal direction, a stiffening in the width direction of the midsole can also be achieved, for accurate local stiffening and flexibility of the sole. By realizing a stiffening in the width direction of the midsole in addition to stiffening of the midsole in the longitudinal direction, a degree of torsional stiffness of the sole can also be achieved for optimal force transmission of the foot to a surface.

One or more of the intended objectives is achieved in particular by the fact that the present invention provides a system of the kind described in the preamble which system comprises a midsole or shoe as described herein and a processor, wherein the system is characterised by the fact that the unlockable fixation means are communicatively coupled to the processor which is arranged to communicate a signal to the fixation means in order to realise a locking or unlocking thereof. This makes it possible for a user to set when the fixation means should realise a locking or unlocking thereof.

In a preferred embodiment the system according to the invention has the characteristic that the processor is provided in the shoe or midsole.

In a further preferred embodiment the system according to the present invention has the characteristic that the shoe or midsole comprises a pressure sensor to register and communicate to the processor a pressure exerted by a user of the shoe or midsole on the midsole. The measured pressure on the shoe or midsole can be used by the processor to then communicate a signal to fixation means in order to realize locking or unlocking of the sole depending on the measured pressure, for example when exceeding a threshold value that may or may not have been preset.

A further preferred embodiment of the system according to the invention has the characteristic that the shoe or midsole comprises a memory, in particular a rewritable memory, arranged to communicate data stored therein with the processor.

In a further preferred embodiment of the system according to the present invention the memory contains data relating to the setting values for the fixation means.

In, a further preferred embodiment the system according to the present invention is characterised by the fact that the memory contains data relating to force-stiffness ratio values and that the processor is able and arranged to compare a pressure registered by the pressure sensor as a force value with the force- stiffness ratio values stored in the memory in order to realize a stiffness in the midsole corresponding to the registered pressure by locking or unlocking the fixation means.

In a further preferred embodiment the system according to the present invention is characterised by the fact that the system includes a sensor device with a sensor that is capable and arranged to register a position of the shoe in relation to the sensor device and to deliver a single hereof. As such the stiffness of the midsole can be adjusted in dependence of the position of the shoe during use. For example, when running, the stiffness can be reduced when the shoe moves away from a surface to promote comfort and recovery. When the shoe subsequently comes into contact with the ground, the stiffness of the midsole can be increased to achieve optimal force transmission from the foot to the ground. The sensor device can also, for example, register the position of the shoe in a pedaling cycle during cycling, for example in relation to a bicycle frame, to vary the stiffness of the midsole at different stages of the pedaling cycle. For example, it may be desirable to realize high sole stiffness in a phase of the pedalling cycle where relatively high forces are applied to a pedal, for instance in a downward pedaling movement, and comfort and recovery can be enhanced by reducing the sole stiffness in a phase where no or relatively little force is applied to a pedal, for instance in an upward pedaling movement.

In a further preferred embodiment the system according to the present invention is characterised by the fact that the sensor device is provided separately from the shoe or midsole and that the midsole or shoe comprises wireless communication means arranged to communicate with the sensor device to receive and process in the processor a signal delivered by the sensor device. In this way the shoe can be produced without sensor, and thus lighter in weight, while the sensor device can be integrated elsewhere, for example in a bicycle frame or in a bicycle computer. In particular the sensor device can for example be part of a bicycle computer with which a signal of a user delivered power or wattage can be transmitted to the communication means in the midsole or shoe to adjust fully automatically the stiffness of the midsole in accordance. For example at a relatively high power or wattage as registered by the sensor device, above a preset threshold value, for instance when in a climb or with high cycling velocity, the midsole can be brought in or maintained in a stiff state for a good force transmission, while at a registered relatively low power or wattage, below a preset threshold value, for instance in a descent or low cycling velocity, the midsole can be brought in a flexible state for comfort and recovery of the foot.

In a further preferred embodiment the system according to the present inventionis characterized by the fact that the shoe or midsole comprises a power source, in particular a button cell battery, which arranged to supply power to at least the processor. The invention will be further explained and clarified on the basis of a number of embodiments that are illustrated in a drawing. In the drawing, where corresponding parts are indicated with same reference numbers, shows:

Fig. 1 a first embodiment of a coupling for use in a midsole according to the invention;

Fig. 2 a second embodiment of a coupling for use in a midsole according to the present invention;

Fig. 3 a third embodiment of a coupling for use in a midsole according to the invention;

Fig. 4 a fourth embodiment of a coupling for use in a midsole according to the invention;

Fig. 5 a fifth embodiment of a coupling for use in a midsole according to the present invention;

Fig. 6A-C a first embodiment of a midsole according to the invention in a top view, side view and perspective partial view respectively;

Fig. 7A-C a second embodiment of an midsole according to the invention in a top view, side view and a perspective partial view respectively;

Fig. 8A-D a third embodiment of a midsole corresponding to the invention in a top view, side view, perspective partial view and cross-section view, respectively;

Fig. 9A-C a fourth embodiment of a midsole corresponding to the invention in a top view, a partial view of perspective and a cross-section view, respectively; and

Fig. 10A-C a fifth embodiment of a midsole corresponding to the invention in a top view, a partial view from the perspective and a side view respectively.

It should be noted that the figures are merely representations of

embodiments of the invention, and that these are given as a non-limiting embodiment. In particular, some parts and dimensions may, to a greater or lesser extent, be exaggerated for the sake of clarity.

Figure 1 shows a first implementation example of a link for application in a midsole according to the present invention. As shown, the midsole comprises two interconnected rigid plates 3.5 where the coupling is a movable single coupling that ensures that the two rigid plates 3.5 are connected to each other as in a single hinge joint. Both plates have a rounded end that, like a joint head 7, fits into a designated joint cavity 9 of the other plate. This principle is applied alternately per plate as in a joint. The front plate 3 has two 'joint heads' and a 'joint cavity'. These fit in the two 'joint cavities' and some 'joint head' of the back plate 5. The movable coupling further consists of a pin 11 and a pin casing. The 11 pin extends through both joint heads of the anterior rigid plate 3 and through the single joint head of the posterior plate, so that the pin connects both plates. The pin 11 can be part of a control that allows the plates to be adjusted relative to each other. For example, the pin 11 can be provided with a controllable rotating device within the housing. The housing is attached to the rear rigid plate.

The movable coupling ensures that the inflexible plates 3, 5 can be moved up and down in relation to each other. The plates 3, 5 themselves are inflexible stiff, but with the single or switching couplings the midsole as a whole can be made more flexible. If the movable coupling is open, the midsole is flexible in a longitudinal direction. The midsole 1 can then be moved downwards and upwards. On the other hand, the sole can also be fixed by the fixing parts in the coupling. Flexibilization and fixation can be alternated during performance and is determined by the values set by the user in advance, or during performance, and/or by the pressure exerted by the user on the midsole.

The coupling can be locked to fix plates 3, 5 of inflexible stiff composite relative to each other. If fixed, one continuous plate of inflexible stiff composite is created. The lock can be controlled electronically or mechanically, for example.

Figure 2 shows a second example of a coupling for use in a midsole according to the invention in question. This example corresponds to the single coupling as shown in figure 1 but comprises two relatively short pins 21, 22 instead of a single pin, each of the pins 21, 22 extending into a cavity provided in connecting joint heads on both plates 23, 25.

Figure 3 shows a third example of a link for application in an intermediate sole according to the invention in question. As shown, the clutch includes a clutch that ensures that the two rigid plates are connected to each other by means of an external clutch. The ends of the rigid plates facing each other are rounded like a joint head. On the left and right side of both stiff plates a recess has been made for the outer link. The outer links are connected to each other by means of a set of pins 37, 39 that run through joint heads of both stiff plates 33, 35. Figure 4 shows a fourth example of a coupling for use in a midsole according to the present invention. This example corresponds to the clutch as shown in figure 3 but comprises two sets of relatively short pins 47, 49 instead of a single set of pins, where each set of pins 47, 49 extends from a respective outer link 41, 42 partly into a cavity provided in the rigid plates 43, 45.

Figure 5 shows a fifth example of a coupling for use in a midsole according to the present invention. As shown, the coupling includes a flexible discus 51, for example a disc-shaped body of flexible polymers, which forms a buffer between the ends of the rigid plates 53, 55 which are rounded like a joint head, like the articular disc separates two bone joints.

Figure 6A-6C shows an example of an intermediate sole that includes two linked plates 63, 65 of inflexible stiff composite. When placed in a shoe, the front plate 63 extends from the tips of the toes to approximately the beginning of the user's metatarsal bones. The rear plate 65 covers the metatarsal bones, metatarsal and hind foot. The rigid plates 63, 65 are connected to each other by means of the movable coupling, such as a single coupling according to figure 1. Over the plates, a top layer 61 is coated with flexible polymers that extends from the toes to the heel of the foot. The top layer lies on the stiff plates and when placed in a shoe is provided under the insole of the shoe. The top layer 61 is only glued at the top or otherwise attached (perhaps it is sufficient here and doesn't matter how) to the front plate 63 and to the back of the back plate 65. Furthermore, the top layer 61 of flexible polymers lies loose on the rigid plates. This is necessary in order not to limit the stretchability. Cavities have been made in the top layer in which pressure sensors 67 are placed. A movable single coupling 69 switches the front plate 63 to the rear plate 65. The movable coupling includes a housing 64 and a pin 66. The 64 housing is attached to the rear rigid plate 65. Pin 66 conducts electrical energy and connects both ends of the front rigid plate. As soon as an electrical pulse is sent from the anode through pin 66 to the cathode, the electromagnetic field changes. The plates are disconnected and this makes it possible for the athlete to move the rear stiff plate 65 down and up relative to the front stiff plate 63.

If no electrical impulse is transmitted through the inner ring, the two rigid plates shall not be able to move relative to each other. In its simplest form and with a number of two rigid 63, 65 plates and one movable coupling, the configuration has two positions: out (fixed) or on (movable). The drawing shows this simplest configuration.

Figure 7A-7C shows an example of a midsole with three linked plates 73, 74, 75 of inflexible stiff composite that form a bottom layer. The midsole includes a mechanism for the control and a top layer 71 of polymers with flexible properties at the top of the switched plates 73, 74, 75. Between the plates there are two movable shifting clutches 79. The front movable clutch connects the front plate 73 with a rigid composition to the middle plate 74 with a rigid composition. The rear movable clutch 79 connects the middle plate 74 to the rear plate 75. The shifting clutches 79 are mechanically controlled by means of compression of gases in the front inflexible stiff plate 73. The front plate 73 extends from the tips of the toes to approximately the beginning of the metatarsal bones. The middle plate 74 covers the metatarsal bones and the rear plate 75 covers the metatarsal (the root bones) and the hind foot. Through approximately the middle of the shoe in the longitudinal direction, from the top of the front plate to halfway the metatarsal bones, a groove 72 is inserted in the stiff composite. The groove follows the pattern of the athlete's neutral gait style and is fitted to prevent over- and underpronation of the foot during performance as much as possible and to promote a neutral gait style. In the front plate 73 there are cavities that have a function in the mechanical control. The top layer 71 of flexible polymers extends from the toes to the heel of the foot. The layer lies on the stiff plates and under the insole. The top layer is only

mounted/glued (attached) at the top to the front plate 73 with a stiff composition and at the back of the rear plate 75 with a stiff composition. Furthermore, the top layer 71 of flexible polymers lies loose on the rigid plates. This is necessary in order not to limit the stretchability. In the top layer 71 there are cavities in which pressure sensors 76 are provided. Through the plates, at the top of the hinge casing, two channels are provided in the longitudinal direction of the shoe, for example tubes that are mounted in the plates. Cords 77 run through these tubes to control the mechanism.

The two front cavities in the front rigid plate 73 form compression chambers 78a. Here air or a gas is stored. The two rear cavities in the front rigid plate form airlocks 78b. Membranes 70 connecting the two front cavities (the compression chambers 78a) with the two back cavities (the airlocks 78b) form a barrier for air flowing out of the compression chamber into the airlock. Two non-elastic cords 77 connected to the airlock on one side run through the 'joint heads' of both plates and connect the compression chamber 78a and the airlock 78b to the rear rigid plate 75. In use, a user of the midsole will press air into and out of the airlocks and the 78a compression chamber by applying pressure to the front rigid plate 73, thereby pulling or lowering the cord, creating space to make the back of the sole more flexible. This is a stepless transmission of force. An alternative control is by means of a button cell battery. In this case, the force-stiffness ratio determines the extent to which the airlocks push air in and out of the compression chamber. A rotation or step proceeds as follows. A user such as an athlete applies pressure to the front rigid plate 73. For example, if the user enters a hill or if the user walks up a staircase, the pressure is high. The user pushes air (or gas) from the airlock 78b through the membrane 70 into the compression chamber 78a. The two non-elastic cords are tightened and the stiff plates are pulled close together. If the pressure is so high that the 78b airlock is completely empty, the lock is locked. The sole of the foot now consists of one rigid plate. As soon as the pressure drops, air (or gas) flows from the compression chamber 78a back into the airlock and the sole returns to its original state.

As shown in figure 8A-8D a fixation of the midsole can be achieved by mechanically locking the coupling between the forefoot part of the midsole and the hind foot part of the midsole by means of a fluidum in the midsole. The midsole comprises, from top to bottom, a top layer 81 of polymers with flexible properties, a one-piece sheet of inflexible stiff composite with high modulus of elasticity and three transverse grooves 82, and a mechanical control by means of tubes 84a, 84b, 84c, 84d filled with fluid. The top layer 81 of flexible polymers extends from the toes to the heel of the foot. The layer lies on the stiff plates and under the insole. The top layer is only mounted/glued at the top to the front plate with a stiff composition and at the back of the back plate with a stiff composition.

Furthermore, the top layer 81 of flexible polymers lies loose on the rigid plates.

This is necessary in order not to limit the stretchability. Cavities have been made in the top layer in which pressure sensors can be placed. The pressure points in the top layer are 86. There are three pressure points connected to the hydraulic control. Two pressure points are provided at the height of the ball of the foot (the bone end of the metatarsals) and one pressure point is provided at the height of the hind foot. The bottom layer consists of one plate 83 of inflexible stiff composite. In this plate two parallel semi-flexible tubes 84a, 84b, 84c, 84d are placed lengthwise twice. The tubes 84a, 84b, 84c, 84d have a reinforced outer wall and are divided from the inside into segments of permeable membranes. The fluid-filled tubes have a function in mechanical control, stabilization of the foot and lifting of over- or underpronation. Depending on the strength and elasticity of the composite, grooves 82 provide limited flexibility of the sole in width and length. In the absence of a coupling, this sole is locked by means of hydraulic pressure pins 85 which are activated when sufficient pressure is applied to the sole. At maximum pressure at the front pressure point, the 84a, 84b, 84c, 84d tubes are completely filled with fluid and the hydraulic pressure pin 85 is activated, which means that the flexibility of the composite is virtually nil.

This configuration of figure 8 comprises four semi-flexible tubes 84a, 84b, 84c, 84d that run straight through the rigid plate and 'at the surface' reach pressure points 86. The space of the tubes 84a, 84b, 84c, 84d is limited by the rigid plate 83. The tubes are semi-flexible. By applying pressure to a front part of the rigid plate, the user will drive fluid backwards. This is a stepless transmission of force. Alternatively, this can be controlled by a button cell battery. In this case the force-stiffness ratio determines to what extent the fluid is pushed through the tubes. A rotation or step proceeds as follows. The user, for example an athlete, applies pressure to a pressure point 86. The pressure point is connected to a semi- flexible tube 84a, 84b, 84c, 84d filled with fluid. The tube is constructed as a reed stem. Reinforced on the outside and divided into segments on the inside separated by permeable membranes. Through the pressure the fluid propels from segment to segment backwards. When the athlete presses hard on the sole, the tube is completely filled with fluid. By varying the amount of fluid in the tube beforehand, the athlete can influence the moment the tube is completely filled with fluid. With sufficient pressure, the fluid activates a hydraulic pressure pin 85 which slides under the weakening grooves 82 and thus prevents the plate from becoming more flexible. As soon as the pressure drops, the fluid pushes forward again. The hydraulic pressure pin 85 is deactivated and the shoe sole springs back to its original shape. If the athlete applies pressure to the pressure point in the heel, the fluid connected to that pressure point pushes forward. This cancels out the effect of over- or underpronation.

As shown in figure 9A-9C the midsole comprises two linked plates 93, 95 of inflexible rigid composite forming a bottom layer. Furthermore, the midsole includes a top layer of polymers with flexible properties. In addition, the midsole features a control mechanism in the form of compression chambers 96a, 96b and a locking mechanism using pressure pins 92a, 92b. The front plate 93 extends from the tips of the toes to approximately the beginning of the metatarsal bones. The middle plate covers the metatarsal bones and the rear plate 95 covers the metatarsal (the root bones) and the hind foot. The front plate contains cavities that have a function in mechanical control. The two rigid plates 93, 95 are connected to each other by means of a movable 94 clutch. The top layer 91 of flexible polymers extends from the toes to the heel of the foot. The layer lies on the stiff plates and under the insole. The top layer 91 is only mounted/glued at the top to the front plate with a stiff composition and at the back of the rear plate with a stiff composition. Furthermore, the top layer 91 of flexible polymers lies loose on the rigid plates. This is necessary in order not to limit the stretchability. Cavities have been made in the top layer 91 in which pressure sensors can be placed. Through the plates, at the top of the hinge casing, two tubes 98a, 98b are mounted in the plates in the longitudinal direction of the shoe. Through these tubes run the cords 99a, 99b which are important for the control of the mechanism. The front cavity in the front rigid plate 93 is the second compression chamber 96b. Fluid is stored here. The rear cavity in the front rigid plate is the first compression chamber 96a. Between the first 96a and second compression chamber 96b a lock body 97 or lock gate is provided. Two inelastic cords 99a, 99b connected to lock gate 97 pass under pressure point 90 through the 'joint heads' of both plates and connect the compression chambers and lock gate to the rear rigid plate. Two pressure pins 92a, 92b in the head of the rear plate are connected to the inelastic cords. These pins 92a, 92b are activated as soon as the pressure is high enough. A user, such as an athlete, can push the lock gate 97 forward by applying pressure to the front rigid plate 93, thereby pulling or lowering the cord, creating space to make the back of the sole more flexible. This is a stepless transmission of force. An alternative is that this is controlled by a button cell battery, in which case the force-stiffness ratio determines the extent to which the airlocks push air into and out of the compression chamber. A rotation or step is as follows. The athlete applies pressure to the front rigid plate 93. When the cyclist enters a hill or when the runner climbs a staircase, the pressure is high. The athlete pushes air (or gas) from the airlock through the membrane into the compression chamber. The two non-elastic cords 99a, 99b are tightened and pull the stiff plates close together. If the pressure is so high that the airlock is completely empty, the lock is locked. The sole of the foot now consists of one rigid plate. As soon as the pressure drops, the compressed fluid from the second compression chamber pushes the lock gate backwards.

Furthermore, the spring of the pressure pin pulls the pin back into the sheath of the rear plate. The sole can now become more flexible.

As shown in figure 10A-10C in a further example, the midsole includes two connected plates 103, 105 of rigid or inflexible stiff composite, one of which forms a forefoot part of the midsole and the other a rear part of the midsole. A fixation of the midsole can be achieved by mechanically locking the coupling between the forefoot part of the midsole and the rear part of the midsole by means of electrical pressure pins 102a, 102b. The midsole further includes a mechanism (in box) 108 for the control, a top layer 101 of polymers with flexible properties, an

electromagnetic fixant, and a digitized control of the coupling by means of an electromagnetic primary power source. The first picture 103 reaches from the tips of the toes to about the beginning of the metatarsal bones. The second picture 105 covers the metatarsal bones, metatarsal (the root bones) and hind foot. The stiff plates are connected to each other by means of the movable coupling 104. The top layer 101 of flexible polymers extends from the toes to the heel of the foot. The layer lies on the stiff plates and under the insole. The top layer 101 is only mounted/glued at the top to the front plate with a stiff composition and at the back of the back plate with a stiff composition. Furthermore, the top layer 101 of flexible polymers lies loose on the rigid plates. This is necessary in order not to limit the stretchability. Cavities have been made in the top layer 101 in which pressure sensors can be placed. The single coupling switches the front plate 103 with a stiff composition to the rear plate 105 with a stiff composition. The movable coupling consists of a housing and a pin 104. The housing is attached to the rear rigid plate 105. The pin 104 conducts electrical energy and connects both ends of the front rigid plate. As soon as an electrical pulse is sent from the anode through pin 104 to the cathode, the electromagnetic field changes. The plates are disconnected and this makes it possible for the athlete to move the rear stiff plate down and up relative to the front stiff plate.

If no electrical pulse is sent through the inner ring, the two rigid plates 103, 105 shall not be able to move relative to each other. In its simplest form and with a number of two stiff plates 103, 105 and one movable coupling, the configuration has two positions: out (fixed) or on (movable). Figure 10 shows this simplest

configuration. The electromagnetic control is as follows. The midsole contains a button cell battery, a memory chip, a processor and three pressure sensors that register the number of watts that are applied to the sole of the shoe. Prior to the performance, the athlete determines his/her personal power-stiffness ratio. The pressure (measured in Watts) exerted by the athlete on the sole determines the degree of stiffness of the sole. During performance, the athlete puts pressure on the sole. Sometimes on the outside or inside of the forefoot, sometimes on the midfoot and sometimes on the hind foot. This is very personal. The pressure sensors in the sole continuously detect the pressure exerted on the sole. The measured value is communicated to the processor

The processor communicates with the memory chip. The measured value is fed into a force-stiffness ratios table. The measured force value is offset by the corresponding stiffness. The memory chip communicates the selected stiffness value with the processor. The processor communicates with the movable coupling. The movable coupling opens or closes completely or partially depending on the pressure measured by the processor. As soon as the pressure on the pedal/sole of the shoe is released, the flexible-elastic composite ensures that the sole springs back to its original position.

Whether the coupling is opened or closed depends on the pressure and the part of the shoe sole on which the athlete puts pressure on the sole. An athlete who puts a lot of pressure on the front surface of the sole (for example the running sprinter or the cyclist in a climb) needs an inflexible or stiff sole, so with that performance the movable coupling is closed. With less intensive activity, an athlete puts less pressure on the sole. He/she then needs a more flexible sole to prevent injuries, to create more rest for the foot and to prevent a burning sensation of the pressure points. The pressure sensors detect the pressure exerted on the sole. The sensors communicate with the processor. For example, the pressure can be measured in Watts. The processor incorporates the pressure sensor measurements into the force-stiffness ratio. Based on predetermined values (factory setting or personalized by the cyclist), the force-stiffness ratio determines whether an electrical impulse should be given to the movable coupling and fixers. The pressure sensors, button cell battery, processor and memory chip are processed as a mechanism 108 in the middle layer of the shoe sole. In figure 10 the mechanism 108 is incorporated in the front plate 103. The mechanism 108 can also be incorporated in one of the other plates if there is room for it. In the simplest configuration, a revolution or step is as follows. The pressure gauge continuously records the pressure applied to the midsole. The processor receives the registration and places the value in the force-stiffness ratio table. The recorded value is linked to the desired stiffness that matches the value. The force-stiffness ratio can be pre set by the rider. It can also be the factory setting. By means of an app on a smartphone or other digital means of communication, the setting can even be changed during performance. In the simplest configuration, the registered value is linked to two possible outcomes: on or off. It is a stepped transmission. If the sole consists of more than two plates, the number of steps in the transmission increases exponentially. If the pressure sensor under the forefoot has a high value, the athlete puts a lot of pressure on the sole. At this point, the athlete benefits from a stiff sole. An electrical impulse is sent through the pin 104. The magnetic field changes and the connection between the two sole plates is fixed. Furthermore, the electric pulse activates one or more pressure pins 102a, 102b which are inserted from the front plate into the holder of the second plate and thus lock the coupling. As soon as the pressure is released because the athlete has taken the step or because he/she has completed the rotation, the connection is released again. The sole springs back to its original shape. At a low value, the athlete puts little pressure on the sole of the shoe. A sole that is too stiff hinders the athlete and he/she benefits from a flexible sole. The result will be that the coupling in the sole of the shoe will be open. The pressure pin 102a, 102b springs back into the sheath of the front plate and an electrical impulse is sent through the anode. The magnetic field changes and the connection between the two sole plates is released. It will be clear to the person skilled in the art that the invention is not limited to the implementation examples discussed here, but that many implementation variants are possible within the scope of the invention as expressed in the conclusions below.

Claims

1. Midsole for a shoe, in particular a sports shoe, comprising a body that is arranged to be placed between an outsole and an insole of the shoe, which body comprises a forefoot part that is arranged for positioning at a forefoot side of the shoe and a hind foot part that is arranged for positioning at a hind foot side of the shoe, wherein the forefoot part is adjustable in relation to the hind foot part, characterized in that the body is provided with unlockable fixation means arranged to fix, in use, the forefoot part in relation to the hind foot part.

2. Midsole according to claim 1, characterized in that the body comprises at least two mutually hinged linked plates.

3. Midsole according to claim 2, with the characteristic that a first of the plates comprises the forefoot part and a second of the plates comprises the hind foot part.

4. Midsole according to claim 2 or 3, with the characteristic that the plates are hinged together through a rotation axis.

5. Midsole according to claim 4, with the characteristic that the forefoot part is rotatable around the rotation axis between a first position and at least a further position, and where the fixation means are arranged to fix the forefoot part in the first position or at least one further position.

6. Midsole according to claim 5, with the characteristic that the fixation means include an electromagnetic source arranged to guide an electromagnetic pulse through the axis of rotation.

7. Midsole according to claim 6, with the characteristic that at least the forefoot part comprises a pressure point zone provided with a pressure sensor arranged to communicate a registered pressure on the forefoot part to the fixation means.

8. Midsole according to claim 1, with the characteristic that the body is one-piece, wherein the forefoot part extends integrally from the hind foot part and wherein the forefoot part is adjustable in relation to the hind foot part along a weakening zone in the body.

9. Midsole according to claim 8, with the characteristic that the weakening zone comprises one or more grooves in the body.

10. Midsole according to claim 8 or 9, with the characteristic that the fixation means include a cavity in the body filled with a movable fluid, which cavity extends from the forefoot part towards the hind foot part through the weakening zone of the body.

11. Midsole according to claim 1 or 8 or 9, with the

characteristic that the fixation means comprise a rotatable flexing element extending between the forefoot part and the hind foot part in the body, wherein the flexing element is rotatable in the body about a rotation axis in a longitudinal direction of the midsole, wherein the flexing stiffness of the flexing element depends on the rotational orientation of the flexing element about the rotation axis.

12. Midsole according to claim 11, with the characteristic that the flexing element comprises an operator element arranged for manual rotation of the bending element in the body.

13. Midsole according to one or more of the previous claims, with the characteristic that the hind foot part and the forefoot part are provided in an bottom layer of the body and that the body includes on an upper side an elastic top layer that is coupled to the bottom layer.

14. Midsole according to one or more of the previous claims, wherein the fixation means are arranged to fixate a right foot part relative to a left foot part of the midsole.

15. Shoe, in particular a sports shoe, comprising a shoe upper, an outsole, and a midsole fitted between the shoe upper and the outsole, characterized in that the midsole is a midsole according to one or more of the foregoing claims.

16. System for adjusting a stiffness of a midsole of a shoe, comprising a midsole according to one or more of the claims 1-14, or a shoe according to claim 15, and including a processor, with the characteristic that the unlockable fixation means are communicatively coupled with the processor which is arranged to communicate a signal to the fixation means in order to realise a locking or unlocking thereof.

17. System according to claim 16, with the characteristic that the processor is provided in the shoe or the midsole.

18. System according to claim 16 or claim 17, with the characteristic that the shoe or midsole contains a pressure sensor to register and communicate to the processor a pressure exerted by a user of the shoe or midsole on the midsole.

19. System according to one or more of the claims 16 - 18, having the characteristic that the shoe or midsole comprises a memory, in particular a rewritable memory, arranged to communicate data stored therein with the processor.

20. System according to claim 19, with the characteristic that the memory comprises data with respect to setting values for the fixation means.

21. System according to claim 16 and one or more of claim 19 and claim 20, characterized in that the memory comprises data relating to force-stiffness ratio values and that the processor is able and arranged to compare a pressure registered by the pressure sensor as a force value with the force-stiffness ratio values stored in the memory in order to achieve a stiffness in the midsole corresponding to the registered pressure by means of a closure or unlocking of the fixation means.

22. System according to one or more of the claims 16 - 21, with the characteristic that the system includes a sensor device with a sensor that is able and arranged to register a position of the shoe in relation to the sensor device and to deliver a signal hereof.

23. System according to claim 22, characterized in that the sensor device is provided separately from the shoe or midsole and that the midsole or shoe comprises wireless communication means arranged to communicate with the sensor device to receive and process in the processor a signal dehvered by the sensor device.

24. System according to one or more of the claims 16 - 23, with the characteristic that the shoe or midsole comprises a power source, in particular a button cell battery, arranged to supply power to at least the processor.