Orthotic insert and method of making the same

Abstract

The present invention provides orthotic inserts which are designed to accommodate a wide range of individuals in ready-made shoes. The orthotic inserts are compatible with a variety of shoe sizes and styles and provide a cost efficient alternative to custom made orthotics. The invention further provides methods for manufacturing the orthotic inserts in an efficient continuously automated manner.

1 . A method for producing an arched orthotic insert having a desired rigidity, comprising:
 a) determining an arch deflection strength for an orthotic insert having a desired length and a desired thickness by correlating the desired length with a calculated average body weight of a group of insert users; and,   b) forming the orthotic insert from one or more polymers present in a ratio to provide the arch deflection strength defined in (a), wherein the one or more polymers is polypropylene (PP) or polypropylene (PP) admixed with thermoplastic elastomer (TPE), thereby producing an arched orthotic insert of a desired rigidity.   
     
     
         2 . The method of  claim 1 , wherein the PP and TPE are present in a ratio from about 100:0 to 50:50. 
     
     
         3 . The method of  claim 1 , wherein the PP and TPE are present in a ratio from about 100:0 to 80:20. 
     
     
         4 . The method of  claim 1 , wherein the one or more polymers consists essentially of PP. 
     
     
         5 . The method of  claim 1 , wherein the arch deflection strength is between about 14 to 28 ft/lb. 
     
     
         6 . The method of  claim 1 , wherein the desired length is between about 130 to 190 mm. 
     
     
         7 . The method of  claim 1 , wherein the desired thickness is between about 0.5 and 2.0 mm. 
     
     
         8 . The method of  claim 1 , wherein the length and arch deflection strength measurements of the insert are selected from the group of measurements consisting of a length of 133 to 143 mm and an arch deflection strength of 12 to 16 ft/lb; a length of 144 to 154 mm and an arch deflection strength of 15 to 19 ft/lb; a length of 155 to 165 mm and an arch deflection strength of 19 to 23 ft/lb; and a length of 166 to 175 mm and an arch deflection strength of 23 to 27 ft/lb. 
     
     
         9 . The method of  claim 1 , further comprising forming a reinforcement structure on the insert. 
     
     
         10 . The method of  claim 9 , wherein the reinforcement structure is positioned under the arch. 
     
     
         11 . The method of  claim 10 , wherein the reinforcement structure is a rib. 
     
     
         12 . The method of  claim 1 , further comprising forming a layer of thermoplastic elastomer over the insert. 
     
     
         13 . The method of  claim 12 , wherein the thermoplastic elastomer has a Shore A hardness value of between about 5 and 50. 
     
     
         14 . The method of  claim 12 , wherein the layer of thermoplastic elastomer comprises a cavity in a heal region of the insert. 
     
     
         15 . The method of  claim 14 , further comprising injecting the cavity with a second thermoplastic elastomer having a different hardness than that of the layer. 
     
     
         16 . The method of  claim 15 , wherein spacers are provided in the heal region of the insert to prevent deflection of the insert during injection. 
     
     
         17 . The method of  claim 12 , further comprising adhesively applying a top overlay. 
     
     
         18 . The method of  claim 12 , further comprising adhesively applying a bottom overlay. 
     
     
         19 . The method of  claim 1 , further comprising trimming excess material resulting from manufacture from the insert. 
     
     
         20 . The method of  claim 19 , wherein the excess material is trimmed using a heated blade. 
     
     
         21 . An orthotic insert produced by the method of  claim 1 . 
     
     
         22 . The orthotic insert of  claim 21 , wherein the PP and TPE are present in a ratio from about 100:0 to 50:50. 
     
     
         23 . The orthotic insert of  claim 21 , wherein the PP and TPE are present in a ratio from about 100:0 to 80:20. 
     
     
         24 . The orthotic insert of  claim 21 , wherein the one or more polymers consists essentially of PP. 
     
     
         25 . The orthotic insert of  claim 21 , wherein the arch deflection strength is between about 14 to 28 ft/lb. 
     
     
         26 . The orthotic insert of  claim 21 , wherein the length is between about 130 to 190 mm. 
     
     
         27 . The orthotic insert of  claim 21 , wherein the thickness is between about 0.5 and 2.0 mm. 
     
     
         28 . The orthotic insert of  claim 21 , wherein the arch height is between about 20 to 25 mm. 
     
     
         29 . The orthotic insert of  claim 21 , further comprising forming a reinforcement structure on the insert. 
     
     
         30 . The orthotic insert of  claim 29 , wherein the reinforcement structure is positioned under the arch. 
     
     
         31 . The orthotic insert of  claim 30 , wherein the reinforcement structure is a rib. 
     
     
         32 . The orthotic insert of  claim 21 , further comprising a layer of thermoplastic elastomer disposed over the insert. 
     
     
         33 . The orthotic insert of  claim 33 , wherein the thermoplastic elastomer has a Shore A hardness value of between about 5 and 50. 
     
     
         34 . The orthotic insert of  claim 32 , wherein the layer of thermoplastic elastomer comprises a second thermoplastic elastomer having a different hardness than that of the layer disposed in a heel region of the insert. 
     
     
         35 . The orthotic insert of  claim 21 , wherein the length is between about 133 to 143 mm and the arch deflection strength is between about 12 to 16 ft/lb. 
     
     
         36 . The orthotic insert of  claim 21 , wherein the length is between about 144 to 154 mm and the arch deflection strength is between about 15 to 19 ft/lb. 
     
     
         37 . The orthotic insert of  claim 21 , wherein the length is between about 155 to 165 mm and the arch deflection strength is between about 19 to 23 ft/lb. 
     
     
         38 . The orthotic insert of  claim 21 , wherein the length is between about 166 to 175 mm and the arch deflection strength is between about 23 to 27 ft/lb. 
     
     
         39 . The orthotic insert of  claim 21 , wherein the length is between about 176 to 188 mm and the arch deflection strength is between about 26 to 30 ft/lb.