Abstract:
A shoe has a sealed insole containing water. The water is controlled to flow around the insole in one (anti-clockwise) direction. The rate of flow is adjustably controllable by ball valve arrangements.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates to footwear.  
           [0003]    2. Description of Prior Art  
           [0004]    The invention relates more particularly to footwear that includes a cavity that overlays a sole of the footwear and into which air can pass or liquid is contained. Such footwear is already generally disclosed using air in WO 87/03789 and U.S. Pat. No. 5,375,345. The cavity serves to improve the comfort of footwear in use by changing the overall cushioning effect of the shoe on the bottom of a user&#39;s foot. Water and air are used in U.S. Pat. No. 4,567,677. Broadly stated where liquid is contained in the cavity it has been found preferable to constrain the liquid to circulate around the area of the sole. As specifically disclosed in U.S. Pat. No. 4,802,289 muscular activity is improved in the feet of a user. U.S. Pat. No. 4,802,289 discloses a similar insole, but has no means of adjusting the flow rate of liquid.  
         SUMMARY OF THE INVENTION  
         [0005]    It is an object of the invention to overcome or at least reduce this problem.  
           [0006]    According to the invention there is provided an article of footwear having an insole comprising a sealed flexible walled cavity filled with fluid for overlaying an elongate sole of the footwear, which cavity is divided longitudinally into a first and second separate elongate chamber extending along a length of the sole in communication with one another at both their ends so as to allow a flow of fluid around the cavity, and at least one manually adjustable one-way valve arranged to control a flow rate of liquid around the cavity.  
           [0007]    The article preferably includes two adjustable valves, one for each of the first and second chambers, and positioned intermediate the lengths of the chambers and laterally opposite one another with respect to the insole.  
           [0008]    The adjustable valve may comprise one or more ball valves.  
           [0009]    The article may include a control member to urge the balls towards and away from respective flow ports to adjust a flow rate of fluid in use through the ports. The control member may extend across an instep of the sole and, when adjusted, is arranged to urge respective balls of one control valve in the first chamber and respective balls of another control valve in the second chamber towards respective ports. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which:  
         [0011]    [0011]FIG. 1 is a part-sectioned side elevation of a shoe; and  
         [0012]    [0012]FIG. 2 is an isometric top view of an insole of the shoe. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0013]    Referring to the drawings, a shoe has a sole  10  and an insole  11  sandwiched between the sole  10  and an upper  12 .  
         [0014]    In FIG. 2, the insole  11  is normally sealed with a flexible lid (not shown) and at least partially filled with water. The insole is divided longitudinally by a partition  13  to form two separate side-by-side elongate first and second chambers  14  and  15  to contain the water in use. Two one-way adjustable valve arrangements  16  and  17  are provided to restrict and control the flow of liquid around inside the insole. Each valve arrangement consists of three channels  18  formed under a respective cover  19  and  20 . Balls  21  are provided to automatically close off each respective channel when required to completely prevent flow of liquid through each of the channels  18  in one direction. Movement of the balls is constrained by a single rotatable control rod  22  that extends across the insole. A series of like conical formations are provided on the rod  22 . The control rod is threaded at one end  23  and is provided with a screwdriver socket  24  (or a small knob). The socket  24  is mounted at the side of the shoe (see FIG. 1) to enable the rod  22  to be rotated as required. It will be apparent, by inspection of FIG. 2, that if the rod  22  is moved, by being screwed inwards say, (or upwards in FIG. 2) the balls  21  are constrained by the respective conical formations at a position closer to entrances of the respective channels  18 . As a result the rate of flow of liquid through the valve arrangements is more restricted, that is, the flow is reduced by such adjustment. In short, the control rod can be used to alter the liquid flow rates, by screwing in or screwing out the control rod  22 . This adjustment can be manually made, as required, using a screwdriver from externally of the shoe.  
         [0015]    It will be appreciated that the control rod  22  may be made in two like parts and arranged so that each part is (manually) adjustable separately. This enables the valve arrangements to be adjusted independently when desired. Also, other suitable valve arrangements may be used.  
         [0016]    In use, liquid in the insole is constrained by the valve arrangements to flow only in one, anti-clockwise, direction and the rate of flow is determined or controlled by adjusting the rod  22  as explained. The insole described is for a right foot. An insole for a left foot is arranged with the valve arrangements to allow liquid to flow only in a clockwise direction.  
         [0017]    It will be noted however that cushioned support is provided by the described insole over a whole area of the bottom of a user&#39;s foot. This ensures good and even cushioning over the whole area of the foot and induces greater flexibility of response when walking or running to varying downward pressures exerted by the foot. The adjustability of the liquid flow rates allows the user to change the cushioning effect, or in other words, the resistance to flexibility of the insole in use. As the fluid flow rate is readily adjustable, the footwear can be easily “converted” for different uses. For example, when running the user may prefer a “softer“ reaction from the insole than when walking normally. In that case, the valve arrangements are manually adjusted to be more open to permit more rapid fluid flow around inside the insole.  
         [0018]    The cavity of the insole is normally filled with water, or some other liquid. The cavity may also be filled with air, or other gases. The cavity may be only partially filled with liquid, in which case the sealed cavity in practice contains a “mixture” of water and air. For this reason, where the specification refers to “fluid”, it is intended that “fluid” has its normal meaning of “liquid or gas” or “liquid and gas”, as appropriate.