Extruded Cushioning Insole

Abstract

The invention is an extruded cushioning insole for footwear. The insole disperses the weight of an individual more evenly across the surface of their foot and reduces the impact forces on the feet when walking, running or jumping. The insole is integrally extruded in a one-piece construction. One insole embodiment includes a flexible upper pad with a plurality of downwardly extending tubes that each form a collapsible internal chamber. Another insole embodiment has a solid main body with a flat upper surface and a contoured lower surface formed by thinner and thicker regions of the insole. Another insole embodiment has a flat upper surface and a convex lower surface formed by a collapsible internal disc-shaped chamber. The convex surface is generally flat when compressed.

1 . An extruded cushioning insole for footwear to provide cushioning for a human foot with a bottom surface when a placing weight on that foot, the footwear having a sole and an upper that forms the sidewalls of the footwear, said extruded cushioning insole comprising:
 a flexible pad having substantially planar and parallel upper and lower surfaces and a perimeter, said pad having a substantially uniform thickness of about 0.06 inch, said perimeter being shaped to supportingly receive the entire bottom surface of the human foot;   a plurality of resilient tubes extending from said lower surface of said pad, said tubes being substantially parallel, uniformly spaced and extending continuously along said lower surface of said pad, each of said tubes having a deformable wall forming a channel with opposed ends;   said pad and tubes being integrally extruded from flexible PVC plastic to form a cushioning insole with a single piece construction, said cushioning insole having a perimeter adapted for placement inside the footwear, said tubes resting on the sole of the footwear and said perimeter of said insole engaging the sidewalls of the footwear to longitudinally and laterally align said insole within the footwear, said tubes and deformable wall being moveable between extended and compressed positions, said flexible pad substantially conforming to the shape of the bottom surface of the foot when in said compressed position; and,   wherein said cushioning insole distributes static forces more evenly across the bottom surface of the foot when in said compressed position, and reduces dynamic forces between the foot and the footwear when placing weight on the foot to move said insole from said extended position to said compressed position, said tubes being resiliently biased to return to said extended position within about 0.25 second when the weight is removed from the foot and insole, said insole resiliently and fully returning to said extended position from said compressed position during the normal life of the footwear.   
   
   
       2 . The extruded cushioning insole of  claim 1 , and wherein each of said deformable walls extends directly from said lower surface of said flexible pad. 
   
   
       3 . The extruded cushioning insole of  claim 2 , and wherein each of said channels is filled with ambient air. 
   
   
       4 . The extruded cushioning insole of  claim 3 , and wherein said deformable wall of each of said tubes includes spaced side wall portions joined by a bottom wall portion, said bottom wall portion being spaced from said lower surface of said pad to form said open channel. 
   
   
       5 . The extruded cushioning insole of  claim 4 , and wherein each of said tubes is spaced apart from its adjacent tube. 
   
   
       6 . The extruded cushioning insole of  claim 5 , and wherein each of said tubes is spaced apart from its adjacent tubes about 0.18 inch, has a height of about 0.25 inch and a width of about 0.38 inch, and said deformable wall has a thickness of about 0.05 inch, and said flexible PVC plastic has a Clash-Berg modulus of rigidity of about 18,000 psi. 
   
   
       7 . The extruded cushioning insole of  claim 6 , and wherein each of said tubes retains an air gap between its said bottom wall portion and said pad when in said compressed position and supporting a 300 pound person. 
   
   
       8 . The extruded cushioning insole of  claim 4 , and wherein adjacent tubes share a common side wall portion. 
   
   
       9 . The extruded cushioning insole of  claim 8 , and wherein said bottom wall portion is arcuate when said insole is in said extended position. 
   
   
       10 . The extruded cushioning insole of  claim 9 , and wherein said pad has a thickness of 0.03 inch, and each of said tubes has a height of about 0.15 inch and a width of about 0.22 inch, and said deformable wall has a thickness of about 0.03 inch, and aid flexible PVC plastic has a Clash-Berg modulus of rigidity of about 1,000 psi. 
   
   
       11 . The extruded cushioning insole of  claim 8 , and wherein said bottom wall portion is flat when said insole is in said extended position, and said flat bottom wall portions combine to form a flexible lower layer parallel to said flexible pad. 
   
   
       12 . The extruded cushioning insole of  claim 3 , and wherein said deformable wall forms a substantially circular tube with a substantially circular cross-sectional shape. 
   
   
       13 . The extruded cushioning insole of  claim 1 , and wherein said upper surface of said pad has a hardness of about 55 to 75 durometers. 
   
   
       14 . The extruded cushioning insole of  claim 1 , and further comprising a separate arch support portion, said cushioning insole and said arch support having spaced apart tubes and matching cross-sectional shapes, said arch support being inverted with its tubes matingly receiving said tubes of said cushioning insole. 
   
   
       15 . The extruded cushioning insole of  claim 1 , and wherein an interior area of said extruded cushioning insole is removed to reduce pressure on the foot in that said interior area. 
   
   
       16 . The extruded cushioning insole of  claim 1 , and wherein said upper surface of said pad has upwardly extending gripping ridges, and is moisture and odor resistant. 
   
   
       17 . The extruded cushioning insole of  claim 1 , and wherein said extruded cushioning insole has demarcations for trimming said perimeter to adapt said insole to fit snuggly inside the footwear. 
   
   
       18 . An extruded cushioning insole for footwear to provide cushioning for a human foot with a bottom surface when a placing weight on that foot, the footwear having a sole and an upper that forms the sidewalls of the footwear, said extruded cushioning insole comprising:
 a flexible pad having a main body, a planar upper surface, a contoured lower surface and a perimeter, said main body having toe, ball, arch, rearward, and heel regions, and said perimeter being shaped to supportingly receive the entire bottom surface of the human foot;   said toe and rearward regions being formed by said main body, and each having a substantially uniform thickness of about 0.18 inch;   said arch region having a first built up portion extending from said main body, said arch region having a substantially uniform thickness of about 0.28 inch;   said heel region having a second built up portion extending from said main body, said heel region having a substantially uniform thickness of about 0.24 inch;   said main body and said first and second built up portions being integrally extruded from flexible PVC plastic to form a cushioning insole with a single piece construction, said perimeter adapted for placement inside the footwear to engage the sidewalls of the footwear to longitudinally and laterally align said insole within the footwear, said insole being moveable between at rest and compressed positions, said flexible pad substantially conforming to the shape of the bottom surface of the foot when in said compressed position; and,   wherein said cushioning insole distributes static forces more evenly across the bottom surface of the foot when in said compressed position, and reduces dynamic forces between the foot and the footwear when placing weight on the foot to move said insole from said at rest position to said compressed position, said cushioning insole being resiliently biased to return to said at rest position within about 0.25 second when the weight of the foot is removed from the insole, said insole resiliently and fully returning to said extended position from said compressed position during the normal life of the footwear.   
   
   
       19 . The extruded cushioning insole of  claim 18 , and wherein said FPVC plastic has a Clash-Berg modulus of rigidity of about 1,000 psi. 
   
   
       20 . The extruded cushioning insole of  claim 19 , and wherein said ball of foot region has a third built up portion extending from said main body, said built up portion of said ball of foot region being sloped between said arch and toe regions. 
   
   
       21 . The extruded cushioning insole of  claim 19 , and wherein said upper surface of said pad has a hardness of about 55 to 75 durometers. 
   
   
       22 . The extruded cushioning insole of  claim 21 , and wherein said upper surface of said pad has upwardly extending gripping ridges. 
   
   
       23 . The extruded cushioning insole of  claim 18 , and wherein said extruded cushioning insole has demarcations for trimming said perimeter to adapt said insole to fit snuggly inside the footwear. 
   
   
       24 . The extruded cushioning insole of  claim 18 , and wherein an interior area of said extruded cushioning insole is removed to reduce pressure on the foot in that said interior area. 
   
   
       25 . An insole extrusion and forming process for making an integral, plastic insole for placing within footwear for a human foot having a bottom surface, the footwear having a sole and an upper that forms the sidewalls of the footwear, said insole extrusion and forming process consisting of the following steps:
 providing an extruder, cooling bath, puller, punch press and wind-up roller, said extruder having a material loading trough and a die;   loading FPVC plastic into said trough of said extruder;   heating said FPVC plastic to molten condition;   extruding said molten FPVC plastic through said die, said molten FPVC plastic having a die exit temperature of about 380° F., and said molten plastic forming an extruded web as it exits said die;   pulling said extruded web via said puller through said cooling bath to cool said extruded web to about 150° F. to form a semi-solid, integrally extruded sheet;   cutting integral plastic insoles from said semi-solid, integrally extruded sheet via a punch press, said punch press cutting said insoles from an interior portion of said integrally extruded sheet to leave excess trim in the form of a continuous sheet that maintains its pullable condition; and,   winding up said continuous sheet of excess trim material via a wind-up roller.   
   
   
       26 . The insole extrusion and forming process of  claim 25 , and wherein said extruder includes a barrel and screw and a gate, said barrel and screw continuously pushing and heating the molten FPVC plastic to a temperature of about 370-380° F., and said molten FPVC plastic being heated to a temperature of about 380° F. at said gate. 
   
   
       27 . The insole extrusion and forming process of  claim 26 , and wherein said extruded web is continuously extruded from said die at a speed of about 4 to 6 feet per minute, and continuously moves through said cooling bath and punch press, and around said wind-up roller. 
   
   
       28 . The insole extrusion and forming process of  claim 27 , and wherein said die has a thickness of about 1¾ inch.