PRONATION CONTROL FOOTWEAR DEVICE FIELD OF INVENTION This invention relates to improved footwear and more particularly to footwear suitable for exercise activity. More especially it relates to inflatable inner soles for footwear.

BACKGROUND OF INVENTION Footwear is required to provide a stable and comfortable support point for the body while being subjected to various types of stress. It is important that the shoe be comfortable and provide adequate support during the various foot movements associated with walking and more particularly athletic activity. Foot pronation is a normal biomechanical characteristic associated with walking or jogging. However, excessive pronation may lead to foot, knee and hip disorders. Increased arch support in footwear is one method of controlling the amount of pronation.

Increased arch support is also of benefit to some users when they are simply standing and hence when pronation is not occurring.

There are various orthopedic and foot related disorders which may arise as a direct or indirect result of ill-fitting footwear which does not provide sufficient support to the longitudinal arch of the foot. The amount of arch support required depends on anatomical peculiarities of an individual as well as the type of activity.

Appropriate arch support is often required to control foot pronation during exercise where anatomical biomechanical abnormalities are exacerbated. However, even in non athletic life styles, arch supports are desirable for some people.

It is known to use prescribed orthotic insoles or inserts to correct problems relating to incorrect footwear as well as possible anatomical peculiarities of the wearer.

However, many of these orthotic devices that are custom made for special shoes will not fit into ordinary shoes and their inherent rigidity makes them

uncomfortable, difficult to measure for use and sometimes can be harmful to the wearer. These individually designed orthotic devices are usually prescribed by and custom made by podiatrists. These are usually made from non deformable plastics and usually are quite expensive.

Alternatively, off-the-shelf orthotic devices may be purchased through retail outlets such as pharmacies. These devices come in a range of standard sizes and often do not adequately compensate for particular foot disorders. Moreover, the construction material of these off-the-shelf orthotic supports is often a deformable foam plastic so that a limited size range of the supports will accommodate a large number of applications. These deformable plastics may deteriorate with use and age leading to an undesirable change in their support characteristics. Therefore, while offering a significantly lower cost option, these off-the-shelf orthotic devices are often ill fitting and also deteriorate with use.

Inflatable cushioning or padding devices in footwear are known and are described in, for example, AU-B-79612/91 (Reebock) and AU-B-53495/90 (Lakic). While various fluids are known as cushioning devices in footwear, air is commonly used for inflatable cushioning devices. Some of these prior art devices use pumps actuated by walking or athletic motion and in some prior art embodiments excess air is circulated to the feet of the wearer for cooling.

In AU-B-79612/91 inflatable devices are disclosed which are intended to fill the space between the foot and the inside of the shoe to improve comfort and also assist with better foot location within the shoe. In this prior art disclosure at least one inflatable bladder is located near the tongue region of a shoe. This disclosure does not relate to inflatable insoles.

AU-B-53495/90 discloses inflatable insoles. As well as providing an inflatable air-

sac in the sole portion of the forefoot region, an arch pillow is provided that in use massages the wearer's foot. However, such prior art devices do not provide the requisite arch support characteristics as may be prescribed by podiatrists or physiotherapists. Furthermore, the air interconnection between the cushioning and massaging sacs leads to a compromise that may be detrimental to optimum cushioning or massaging, especially the latter. Because of this interconnection between the cushioning and massaging sacs, it is not possible for the massaging sacs to provide the requisite arch support continuously. With these prior art devices the pressure on the arch region of the foot will change as the impact force on the sole of the foot changes. Hence different arch pressures will result depending on whether the wearer is involved in low impact or high impact activities, e.g. standing versus jogging. However, even with one activity such as jogging, the force on the sole of the shoe changes greatly as a jogger progresses through a stride cycle. This change in force on the sole would lead to a drastic change in pressure on the arch, possibly leading to injury. The variation in pressure in the arch pillow probably contributes to the massaging effect on the foot.

Insoles such as those disclosed by Lakic provide at least some massaging of the arch. This massage effect would be expected to be variable because of the change in pressure in normal use. However, this may be even desirable for massage purposes.

Accordingly, it is an object of the present invention to provide an inflatable insole that provides improved arch support.

SUMMARY OF THE INVENTION The present invention provides in one form a manually inflatable insole for controlling foot pronation by increasing arch support comprising an insole base attached to an inflatable air-sac connected to an inflator means wherein by manual control of the inflator means the air-sac is inflated or deflated in order to contour

and support the longitudinal arch of the wearer's foot in accordance with his "ideal foot posture" and the requirements of his footwear; the insole base providing a means by which the air-sac is secured within the footwear.

Preferably the inflator means includes an air pump integral to the insole and a control valve, wherein the air-pump is used to increase the air pressure in the air- sac and the control valve is used to decrease the air pressure in the air-sac. While it is convenient to have an integral air-pump in alternative embodiments, an external air-pump may be used.

It will be appreciated that in use a device according to the present invention may provide arch support similar to that of a conventional podiatrist prescribed and custom made arch support and provide the requisite arch support rather than mere cushioning or massaging. It will be further appreciated that by isolating the arch support function from forefoot cushioning via other interconnected air-sacs that the requisite support can be achieved without compromise balancing between arch support and forefoot cushioning. While the insole of the present invention may have other fluid-sac, gel-sac or air-sac forefoot cushioning devices, these are required to operate substantially independently of the arch support air-sac. It will also be appreciated that manual adjustment of the pressure of air in the air-sac enables the "correct" pressure to be established before exercise. The preferred embodiments of the Lakic prior art citation have a pump that is actuated by heel movement. Hence, in the Lakic invention, the requisite pressure is only attained after some exercise. The present invention permits the adjustment to the required support level before exercise commences. A further feature of the insoles of the present invention is that they allow a wearer to adjust the pressure by placing the fingers between the side of the foot and the controls on the insole while standing.

This allows the amount of arch support to be adjusted while the arch support is in static use. Adjustment of the arch support by the controls is an important feature of the present invention and overcomes problems associated with fixed type arch

supports.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of one embodiment of an insole.

Figure 2 is a bottom view of the insole from Figure 1.

Figure 3 is a schematic bottom view of an insole in a shoe.

Figure 4 is a cross section view of Figure 3 cut along line 44.

DETAILED DESCRIPTION OF THE INVENTION Preferred embodiments of the invention are shown in Figures 1 - 4.

Referring to Figure 3, a shoe is shown generally at 1 and an insole at 2. A pump button 3 is located near a valve 4. The pump button 3 is manually successively depressed and released to inflate a bladder 5 (not viewed) located below a base 11.

A valve 4 may be opened by finger pressure to reduce the pressure on the bladder 5. The location of these controls on the side portion of the insole enables these control buttons to be accessed while a wearer is standing in the footwear fitted with the inflatable insole.

Referring to Figure 4, the insole 2 is formed by heat sealing a bladder 5 at contact lines 6. The bladder 5 is made from a thermoplastic elastomer. Connected to the bladder 5 via a flapper valve 7 is an air-pump 8. The construction method and construction materials for these valves, bladders and air-pumps are described in AU-B-79612/91 and the contents of that specification are hereby incorporated into this specification.

Located above the bladder 5 is an upper 9 which is in turn covered with a synthetic fabric 10 to provide an essentially aesthetic appearance to the insole. Joined to the upper 9 is an injection moulded base 11. The base 11, upper 9, bladder 5 and flapper valve 7 are all manufactured from suitable thermoplastic elastomers.

Within the pump 8 is an open cell resilient foam block 12 which facilitates the pumping action by pressing and releasing a pump button 3 forming part of the pump 8.

In operation a wearer inserts the insole 2 into his shoe 1. The wearer, while standing is then able to regulate the pressure in the bladder 5 by either manually pressing and releasing the pump button 3 to increase the pressure or pressing the valve button 4 to reduce the pressure. By varying the pressure of air in the bladder the wearer is able to change the amount of arch support to suit the wearer's requirements. Regulating the pressure in the air-sac or bladder allows the arch support to contour and support the longitudinal arch of the wearer's foot. This can achieve what is regarded by podiatrists and physiotherapists as the "ideal foot posture" for particular footwear and the intended use of the wearer. It is relatively easy for a wearer to ascertain the appropriate arch support for his intended purpose.

Also by varying the amount of pressure in an insole according to this invention it is possible to allow a larger percentage of users to enjoy improved arch support without the need for custom made orthotics. The insole may be used in everyday shoes or may be used in shoes specifically directed towards exercise activity.

While this invention relates primarily to insoles it will be appreciated that a special shoe may be manufactured to accommodate such an insole. In this embodiment it is convenient for the controls to be external to the shoe enabling adjustment from the outside of the shoe.

A pressure gauge may be incorporated into the insole or shoe of the present invention to enable a user to consistently add a predetermined amount of pressure.

Alternatively, an adjustable pressure relief valve may be used to enable similar pressures to be maintained.

It will be appreciated that various manufacturing methods may be used to manufacture the insoles of the present invention without departing from the scope of the present invention.