摘要 |
A thin-walled hollow partially liquid-filled cushion is permanently enclosed in a cavity formed in the sole of a shoe. Preferably, the cushion is produced by vacuum-forming a pan, having a continuous circumferential lip, from a sheet of durable, flexible, resilient, non-porous thermoplastic material, heat sealing a sheet of similar material to all but a small region of the lip, partially filling the pan with a low-viscosity liquid by means of a fine tube inserted between the unsealed lip and sheet, and sealing the sheet to the previously unsealed region of the lip. A critical feature of the invention resides in the formation of the cavity in the shoe sole to contain the cushion with the cushion walls, top and bottom in intimate contact with, and the contents of the cushion under pressure exerted by, the walls, top and bottom of the cavity.
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