Removable liner and inflatable bladder for snowboard boots and method of manufacture
View Patent ↗An inflatable liner for a boot, such as a snowboard boot. An oily chalk like substance consisting of 90% sweet starch, 9% lubricant, and 1% stearate is included between two sheets of plastic that make up bladder of the liner. The bladder is attached to the EVA of the liner before the EVA is folded, stitched, heated and molded. This allows the bladder to be attached while the EVA is still flat and allows attachment to be performed by machine stitching. The bladder is partially inflated before the EVA is heated and molded. The oily chalk like substance and the partial inflation of the bladder allows the installed bladder to pass through the heating and molding steps of the EVA without the two sheets that make up the bladder melting together. The design and installation of the bladder minimizes the amount of slipping of a wearer's foot and heel within the boot.
1. A method of making an inflatable liner for a shoe or boot, said method comprising the steps of:
providing a bladder assembly comprising a first sheet of material and a second sheet of material, wherein the material of each sheet is heat bondable to the other sheet;
applying heat and pressure to the first and second sheets to melt selected areas of the first and second sheets together;
providing a liner assembly comprising a third sheet of material, said third sheet of material comprising a heat-moldable material;
securing the third sheet to the bladder assembly;
subsequently heating the liner assembly together with the bladder assembly to mold the third sheet into a desired shape.
2. The method of claim 1 further comprising the step of:
inflating the bladder assembly prior to heating the third sheet.
3. The method of claim 1 further comprising the step of:
applying a powder between the first sheet of material and second sheet of material prior to applying heat and pressure to the first and second sheets.
4. The method of claim 1 further comprising the step of:
applying oil chalk between the first sheet of material and second sheet of material prior to applying heat and pressure to the first and second sheets.
5. The method of claim 1 further comprising the step of:
applying a mixture of starch and lubricant between the first sheet of material and second sheet of material prior to applying heat and pressure to the first and second sheets.
6. The method of claim 1 wherein the first and second sheets are provided in the form of sheets comprised of thermal polyurethane.
7. The method of claim 1 wherein the third sheet is provided in the form of a sheet comprising ethyl vinyl acetate.
8. The method of claim 1 wherein the first and second sheets are provided in the form of sheets comprised of thermal polyurethane and the third sheet is provided in the form of a sheet comprising ethyl vinyl acetate.
9. The method of claim 1 further comprising the step of cutting the first sheet and the second sheet into a desired shape of the bladder assembly and cutting the third sheet into the desired shape of the liner assembly, prior to the step of heating the third sheet.
10. The method of claim 1 further comprising the steps of:
providing the first and second, sheets in the form of sheets comprised of thermal polyurethane;
applying a powder between the first sheet of material and second sheet of material prior to applying heat and pressure to the first and second sheets, said powder comprising a starch and a lubricant;
providing the third sheet in the form of a sheet comprising ethyl vinyl acetate;
inflating the bladder assembly prior to heating the third sheet; and
cutting the first sheet and the second sheet into a desired shape of the bladder assembly and cutting the third sheet into the desired shape of the liner assembly, prior to the step of heating the third sheet.
11. The method of claim 1 further comprising the step of placing the liner assembly and bladder assembly on a last prior to heating the liner assembly.
12. The method of claim 1 further comprising the step of folding and stitching the liner assembly as desired to approximate the desired shape of the desired liner assembly.
13. A method of manufacturing an article of clothing with a liner and an inflatable bladder comprising the steps of:
applying a powdered oil chalk to the surface of a first sheet of bladder material;
placing a second sheet of bladder material on top of the first sheet whereby the powdered oil chalk is between the first and second sheet;
cutting the shape of the bladder from the two sheets of bladder material;
creating seams at points where the two sheets of bladder material are to be attached together;
cutting out the shape of the liner from a sheet of EVA;
attaching the bladder to the EVA;
folding and stitching the EVA;
inflating the bladder a small amount;
heating the EVA and first and second sheets and appropriate amount; and
molding the EVA to a final shape corresponding to the article of clothing.