Adjusting device for the arch of the foot of the insole of shoes, boots and the like

An adjustable foot arch for the insole of a shoe, said foot arch being of variable height and shape, comprising:

• a flexible sheet member having an essentially unvariable extension, said flexible sheet member being shaped as a half-dome with an essentially parabolic base having a predetermined curvature, said parabolic base having an apex and an axis passing through said apex, said flexible sheet member being slideable relative to said insole;
• restraining means for slidably connecting said flexible sheet member to said insole at at least three points on said insole, said restraining means limiting sliding movement between said flexible sheet member and said insole to sliding movement in a first direction and sliding movement in a second direction, said first and second directions being substantially perpendicular to each other, said first direction extending along a chord of said parabolic base and said second direction extending along said axis passing through said apex;
• height varying means, adjustably insertable between said half-dome and said insole, for varying the height of at least one point on said flexible sheet member relative to said insole so as to change said curvature of said flexible sheet member;
• adjustment means, operably connected to said height varying means, for causing adjustable insertion of said height varying means between said half-dome and said insole, said adjustment means being accessible externally of said shoe and being operable by the wearer of said shoe, when the shoe is being worn.