Flexible pressure sheet

Abstract

The invention relates to a flexible sheet which includes cavities that are intercommunicated by a captive fluid of a known viscosity and which is positioned as an insole beneath the sole of the foot. The upper surface of the aforementioned cavities receives plantar pressures, thereby acquiring a corresponding dimpled appearance indicating those areas receiving greater or less plantar pressure. The gradual movement of the fluid through the hollow closed circuit is caused mainly by the resistance to the fluid provided by two-way an one-way valves and alternatively by the resistance provided by the cross-section and length of the conduits to the viscosity of the fluid. In this way, as the foot oscillates the cavities remain the same. The invention is mainly intended for obtaining approximate plantar pressure measurements by observing the upper surface of the adjoining cavities after a sufficient number of steps, producing the mould or negative and saving a record of same, and producing the final insole.

1 . A flexible pressure sheet, applicable to an insole for the sole of the foot, said sheet ( 1 ) comprising a number of adjacent flexible cavities ( 2 ) occupied by a fluid and linked together by valve members that shut off the flow of the fluid while pressures below a pre-set value operate these cavities modifying their volume as they deform and shrink in a stable manner, when they receive plantar pressures during walking, characterised in that said cavities ( 2 ) are linked by a number of valve-endowed tubes defining a number of longitudinal channels ( 11 ) fitted inside with a number of spring members ( 10 ), a number of rods ( 8 ) and some caps ( 7 ) or grids limiting the movement of the said rods ( 8 ) into the cavities ( 2 ). 
     
     
         2 . A flexible pressure sheet, according to  claim 1 , characterised in that the springs of the said valve-endowed tubes are metallic or polymeric. 
     
     
         3 . A method for the development of an insole for the sole of the foot comprising:
 using a flexible pressure sheet according to  claim 1 , by walking a sufficient number of steps so that a succession of pressures on the flexible sheet is generated that will provide a good approximation to the average of pressures in a plurality of areas;   obtaining from said used flexible pressure sheet a surface with protrusions and valleys that record the plantar pressure after walking;   placing a sheet of soft consistency and low hardness on said surface;   providing, after separation of said sheet of soft consistency and low hardness, a negative mould, with a surface that has a number of high areas, corresponding with the areas of maximum impact, and other thin areas of little or no support; and   attaching a hard sheet to this surface with soft protrusions, thereby obtaining the final insole.   
     
     
         4 . A method, according to  claim 3 , characterised in that the areas that on the said surface obtained from the plantar pressure present valleys generate a number of corresponding areas in the final insole having a greater amount of soft material and little hard material. 
     
     
         5 . A method, according to  claim 3 , characterised in that the areas that on the said surface obtained from the plantar pressure present high areas generate a greater amount of hard material and little soft material in the final insole. 
     
     
         6 . A method, according to  claim 6 , characterised in that the material used for said negative mould is silicone.