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.

Description:
CROSS REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This application claims the benefit of priority under 35 U.S.C. §119(e) of U.S. Ser. No. 61/469,647, filed Mar. 30, 2011, the entire contents of which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates generally to orthotic inserts for use in footwear, and more specifically to an arched orthotic insert having a defined rigidity as well as a method of manufacturing the same. 
         [0004]    2. Background Information 
         [0005]    Orthotic inserts are used in conjunction with various types of footwear to enhance the functions of a person&#39;s foot. Several orthotics as well as methods of manufacturing orthotics are known in the prior art. See for example, Meyer, U.S. Pat. No. 4,669,142; Sloane, U.S. Pat. No. 2,742,657; Daley, U.S. Pat. No. 4,979,252; Cumberland, U.S. Pat. No. 4,888,841; and Brown, U.S. Pat. No. 5,772,945. 
         [0006]    Orthotic inserts have been formed of many different materials, including for example, acrylic plastic, leather, metal, foam, rubber, and fiberglass composites. Orthotic inserts may be soft or rigid, or ideally, include both soft and rigid materials, such as a composite including a rigid component supporting softer materials. The rigid component ideally has a relatively thin vertical thickness dimension and extends from the calcaneal area of the foot (the heel portion) to at least the metatarsal head area of the foot, also known as the “ball” of the foot. The purpose of such orthotics is generally to first position, and then control the movements of, the midtarsal and subtalar joints during the gait cycle which the body goes through in walking and running, and possibly other weight bearing activities. 
         [0007]    Although several ready-made orthotics are known in the prior art, several obstacles interfere with the success of these products. First, there is the problem of providing an orthosis having an appropriate rigidity for a given shoe size such that a maximum range of consumers of varying body weights may be accommodated. Another problem is the fact that a person&#39;s feet do not always fall into the range of standard shoe sizes, widths, and shapes meaning that the orthotic insert may not benefit the person. 
         [0008]    As such, orthotic inserts are needed that accommodate a wide variety of shoe styles and sizes to accommodate a wide range of shoe consumers. Additionally, the orthotic inserts should be able to be easily manufactured to reduce costs making inserts that is available to a wider base of consumers. 
       SUMMARY OF THE INVENTION 
       [0009]    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. As such, in one aspect, the present invention provides a method for producing an arched orthotic insert having a desired rigidity. The method includes 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. Subsequently, the method includes forming the orthotic insert from one or more polymers present in a ratio to provide the determined arch deflection strength to produce the arched orthotic insert having the desired rigidity. In various embodiments, the one or more polymers is polypropylene (PP) or a mixture of PP and thermoplastic elastomer (TPE). In one embodiment, the PP and TPE are present in a ratio from about 100:0 to 50:50, 80:20 or 90:10. 
         [0010]    In another aspect, the present invention provides an orthotic insert produced by the method described herein. In various embodiments, the rigid orthotic insert may have an arch height between about 20 to 25 mm, an arch deflection strength between about 14 to 28 ft/lb, and a length between about 130 to 190 mm. For example, the orthotic insert may have 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; or a length of 166 to 175 mm and an arch deflection strength of 23 to 27 ft/lb. In some embodiments, the orthotic insert may further include a reinforcement structure formed under the arch, such as a reinforcing rib to provide additional rigidity while having a reduced thickness. In various embodiments, the orthotic insert may include one or more additional material layers disposed on the bottom or top of the rigid layer, such as one or more layers of thermoplastic elastomer. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a diagram including multiview projections of a single layer orthotic insert in one embodiment of the invention. 
           [0012]      FIG. 2  is a side view of a multilayer embodiment of the orthotic insert profiling the arch of the insert moving from the heel region (A) of the insert to the toe region (B) of the insert. The arch deflection pressure point is indicated by an arrow. 
           [0013]      FIG. 3  is a diagram including a section view and exploded section view showing a reinforcing rib structure disposed on an orthotic insert included under the arch area of the insert in one embodiment of the invention. 
           [0014]      FIG. 4  is a diagram including multiview projections of an orthotic insert in one embodiment of the invention in which the insert includes a rigid layer along with at least one layer of thermoplastic elastomer and configured to provide support on non-athletic shoes. 
           [0015]      FIG. 5  is a diagram including multiview projections of an orthotic insert in one embodiment of the invention in which the insert includes a rigid layer along with at least one layer of thermoplastic elastomer and configured to provide support on athletic shoes. 
           [0016]      FIG. 6  is a diagram including a plan view and section view showing a cross-section along the length of an orthotic insert in one embodiment of the invention. 
           [0017]      FIG. 7  is a diagram including a section view showing a cross-section along the length of an orthotic insert with an exploded section view showing an embodiment of an orthotic insert including standoffs indicated by arrows which assist in preventing collapse of the orthotic insert during over molding processes along with adding stability to the heel region of the orthotic. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    Before the present device and method are described, it is to be understood that this invention is not limited to a particular structure or method of manufacture as such parameters may vary. It is also to be understood that the terminology used herein is for purposes of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only in the appended claims. 
         [0019]    As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. Thus, for example, references to “the method” includes one or more methods, and/or steps of the type described herein which will become apparent to those persons skilled in the art upon reading this disclosure and so forth. 
         [0020]    Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the invention, as it will be understood that modifications and variations are encompassed within the spirit and scope of the instant disclosure. All publications mentioned herein are incorporated herein by reference in their entirety. 
         [0021]    Referring to the drawings in detail, wherein like reference numerals represent like parts throughout, reference numeral  100  refers to a rigid arched orthotic substrate which is generally configured in the outline shown in  FIG. 1 . The rigid orthotic substrate  100  is shown in multiple perspective views and includes a generally arched bottom surface  102 . It will be understood that, when in use, the top surface  103  of the device will normally be disposed upwardly to receive the bottom of the person&#39;s foot with optional additional layers as discussed herein. It will also be understood that the orthotic substrate  100  will in many embodiments serve as the main structural member of an orthotic insert which incorporates other elements in its construction, and in particular may be covered with additional layers of one or more material, such as resilient material for the comfort of the wearer. 
         [0022]    The orthotic substrate  100  is an elongate structure having a forward edge  104  which is configured to lie proximate to the metatarsal head area of the wearer&#39;s foot, and a rearward edge  105  which generally surrounds a heel cup  106 . Along its sides, the device is bordered by medial and lateral edges  108 ,  110 . 
         [0023]    The orthotic substrate  100  appears in  FIGS. 2 ,  4 ,  5  and  6  in assembled configurations including additional layers, such as one or more additional top and/or bottom layers. For the purpose of describing the elements of the structures, reference is made to the cross-section shown in  FIG. 6 . As can be seen, the primary structural member or of the assembly is provided by layer  100  and is generally rigid so as to withstand deflection of the arch under various downward forces resulting from weight and movement of the wearer. 
         [0024]    Strength and rigidity of orthotic substrate  100  are imparted by the type and ratio of components used to form the substrate. As can be seen in  FIG. 6 , the primary purpose of orthotic substrate  100  is to impart a degree of strength and rigidity to the orthotic as a whole, while allowing the addition of other layers to further control comfort and other characteristics. 
         [0025]    In embodiments illustrated for example in  FIGS. 2 ,  4  and  5 , orthotic substrate  100  is supplemented by additional layers which provide characteristics consistent with particular shoe types, for example non-athletic or dress shoes ( FIG. 4 ) or athletic shoes ( FIG. 5 ). As will be described in greater detail below, one or more of these additional layers may be added, as may be desired for a particular application. 
         [0026]    In one aspect, the present invention provides a method for producing an arched orthotic insert having a desired rigidity which is imparted by the type and ratio of polymer utilized to form orthotic substrate  100 . The method includes 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. In calculating the average weight of a group of insert users, it is desirable to take into account marketing data as to the average height of user&#39;s of a particular shoe size and style. Such data is then used to correlate an average body weight of the largest estimated percentage of likely users of the orthotic such that a desired deflection strength and rigidity may be achieved by providing an appropriate type and ratio of polymers to form insert  100 . 
         [0027]    As such, the method further includes forming the orthotic insert from one or more polymers present in a ratio to provide the determined arch deflection strength to produce the arched orthotic insert having the desired rigidity. 
         [0028]    Typical arch deflection strengths for orthotic insert  100  range from about 12 to 27 ft/lb. In correlating calculated average body weights with particular orthotic lengths, in various embodiments, the orthotic has a length and arch deflection strength measurement of about 133 to 143 mm and 12 to 16 ft/lb; 144 to 154 mm and 15 to 19 ft/lb; 155 to 165 mm and 19 to 23 ft/lb; 166 to 175 mm and 23 to 27 ft/lb; or 176 to 188 mm and 26 to 30 ft/lb. In some embodiments, the orthotic has a length and arch deflection strength measurement of about 138 mm and 14 ft/lb; 149 mm and 17 ft/lb; 160 mm and 21 ft/lb; 170 mm and 25 ft/lb; and 183 mm and 28 ft/lb. 
         [0029]    One skilled in the art would understand that a range of polymers may be utilized to form an orthotic having a particular rigidity. In some embodiments, the orthotic is formed of PP alone or in combination with varying amounts of TPE. In some embodiments, the PP and TPE are present in ratios from about 100:0 to 50:50, 60:40, 65:45, 70:30, 75:25, 80:20, 85:15, 90:10, or 95:5. In one embodiment, the orthotic has a length of about 183 mm and is formed of 100% PP. In another embodiment, the orthotic has a length of about 170 mm and is formed of 100% PP. In another embodiment, the orthotic has a length of about 160 mm and is formed of PP and TPE present in a ratio of about 90:10. In another embodiment, the orthotic has a length of about 149 mm and is formed of PP and TPE present in a ratio of about 90:10. In another embodiment, the orthotic has a length of about 138 mm and is formed of PP and TPE present in a ratio of about 80:20. 
         [0030]    Suitable polymers for forming the orthotic  100  are known to those skilled in the art, and include the following examples: thermoplastic polymers, such as polypropylene (PP); thermoplastic elastomer (TPEs), such as Product No. Telcar® TL-3954-40, Telcar®TL-2683A, Telcar® TL-2683B, Telcar® TL-2683D, all available from Teknor Apex Company. Also, it will be understood that homopolymers, random copolymers, and block copolymers of the type described above may be utilized. Typical polymers for use with the invention include those having a Shore D value between about 30 and 70. 
         [0031]    The orthotics of the present invention may further include a reinforcing structure to assist in achieving desired arch deflections per length while keeping overall thickness of the orthotic at a minimum. As shown in  FIG. 2 , in one embodiment, the reinforcing structure is a rib structure  150  formed under the arch area (backbone reinforcement under the arch area). As shown in  FIG. 2 , in one embodiment the rib is about 1 mm, however, thicker or thinner ribs are envisioned, in which the thicker the rib that is used, the higher the arch deflection strength will be. As such, in various embodiments, the rib may be about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 or 2.0 mm in thickness. 
         [0032]    As discussed herein and shown in embodiments illustrated for example in  FIGS. 2 ,  4  and  5 , orthotic substrate  100  may be supplemented by additional layers which provide characteristics consistent with particular shoe types, for example non-athletic or dress shoes ( FIG. 4 ) or athletic shoes ( FIG. 5 ). To provide additional layers, an overmold process may be utilized. The one or more additional overmold layers may be composed of a number of suitable polymers of desired hardnesses depending on the type of insert application desired, for example, dress shoe or athletic shoe. Polymers for forming the overmold are known to those skilled in the art, and include the following examples: thermoplastic elastomers, such as monprene and faraprene. Also, it will be understood that homopolymers, random copolymers, and block copolymers of the type described above may be utilized. Typical polymers include those having a Shore A value between about 5 and 50. In one embodiment, as illustrated in  FIG. 4  showing an insert for use in dress shoes, the polymer is monprene having a Shore A hardness value of about 7 to 8. In another embodiment, as illustrated in  FIG. 5  showing an insert for use in athletic shoes, the polymer is faraprene having a Shore A hardness value of about 45. 
         [0033]    The composite orthotic, illustrated for example in  FIGS. 2 ,  4  and  5  may be produced in a continuous manufacturing process. Even though the insert may appear to be a single component in various illustrations, it may include one or more additional layers. Typically, the inserts include at least orthotic substrate  100  along with a thermoplastic elastomer layer  120  overmolded onto the orthotic. Additional layers may also be utilized to assist in the manufacturing process, such as a top and bottom cover layer which assist in the manufacturing process. 
         [0034]    In one embodiment, the composite inserts shown in, for example  FIGS. 2 ,  4  and  5  may be assembled from subassemblies. The first including an orthotic assembly of layer  100  and additional layer of overmolded thermoplastic elastomer  120 . The overmold may be formed by any suitable method, such as injection molding. The second assembly includes a top and bottom cover used to sandwich the first assembly. 
         [0035]    The overmolding process may be performed by any suitable method, such as injection molding. An appropriately shaped cavity is utilized to form an injection molded layer on substrate  100 . As shown in  FIG. 6 , overmold material may be injected into the mold through the heel region. As the overmolded layer is formed, deflection of the substrate  100  may be reduced or prevented during injection of the overmold material into the mold cavity by providing spacers in the heel region of the substrate  100 . As illustrated in  FIG. 7 , one or more spacers  200  prevent deflection of the substrate  100  resulting from collapse of the surfaces of the bottom heel which may produce an undesirable composite having witness lines. 
         [0036]    One of skill in the art would understand that additional layers may be provided on or within portions of layer  120 . For example, additional polymer types may be injected into only specific areas during the overmolding process. In this fashion, for example, an insert may be constructed in which the heel region includes layers of polymers of different hardness. 
         [0037]    As discussed above, the second assembly includes a top and bottom cover used to sandwich the first assembly. The top and bottom cover are provided as a laminate in which the top and bottom cover are laminated together, there being a liner strip on the bottom cover that does not permit the top cover to be bonded to the bottom cover in specific areas. This allows for manipulation of the top and bottom cover assembly during assembly such that the top cover may be bent past the toe area and secured with a retention spring in a fixture assembly thereby allowing the liner strip on the bottom cover to be exposed. The first assembly may then be inserted between the separated top and bottom cover as discussed below. 
         [0038]    In various embodiments, the top and bottom cover are placed in a locating fixture-palette with the bottom cover material facing down into the cavity of the fixture nest. Two cavities are provided in the locating fixture nest, one cavity for the left insert of a set and one cavity for the right insert of a set. The top cover in both cavities is pulled towards the toe area and secured with a retention spring. The liner in the bottom cover is peeled to expose an adhesive area. The orthotic composite assembly (e.g., substrate  100  and overmold layer  120 ) is placed in the locating fixture; the frontal width of the orthotic resting on top of the exposed adhesive of the bottom cover. 
         [0039]    Light pressure is then applied to the frontal width of the orthotic to bond the orthotic composite assembly to the top and bottom cover assembly. One skilled in the art would understand that any positive force, such as mechanical, electromechanical or hydraulic pressure, may be applied to press the assembly together. 
         [0040]    The locating fixture slides to the robotic priming station, and an operator activates the priming dispensing cycle. Once the gluing cycle is complete, the operator will slide the locating fixture to the robotic gluing station, an operator activates the gluing cycle. After completing the gluing dispensing cycle, an operator slides the tray out of the robotic enclosure and releases the top cover from the retention spring. The locating fixture slides to the pressing station, an operator activates the pressing cycle to cure the adhesive. 
         [0041]    The combination of the hard orthotic shell with the soft and spongy material cannot be pre-formed due to plastic memory (it springs back), and therefore an additional trimming process after conformal bonding to the substrate  100  is required. As such, after the pressing cycle has concluded, the orthotics are removed from the locating fixture and placed in the stationary locating fixture of the robotic hot knife cutting station, an operator activates the cycle. The assembled orthotics are removed from the stationary fixture, and the pair is placed in a box. The production and trimming process provides a device having the desired outline, as indicated, for example in  FIGS. 4 and 5 . 
         [0042]    The orthotic assemblies can be produced at a factory where access to bulk materials and mass-production techniques are available, and can then be shipped in fully assembled form. Thus production may take place entirely within a single facility to increase production efficiency. The initial molding and overmolding may be conducted rapidly using standardized and/or automated techniques. 
         [0043]    The following examples are intended to illustrate but not limit the invention. 
       Example 1 
     Orthotics 
       [0044]    This example illustrates 5 embodiments of specific orthotic inserts manufactured. 
         [0045]    Five specific orthotic inserts having the dimension outlined in Table 1 below were manufactured. The orthotics were designed to fit on men&#39;s and women&#39;s shoes. Exhaustive fitting and measuring of men&#39;s and women&#39;s shoes was conducted. The measurements outlined in Table 1 are not coincidental but designed to fit at least 85% of the current shoes in the market. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Specific Shape of Orthotics 
               
             
          
           
               
                   
                   
                 Over All 
                 Heel 
                 Frontal 
                   
                   
                   
                   
               
               
                   
                   
                 Length 
                 Width 
                 Width 
                   
                   
                   
                 Arch - 
               
               
                 Size 
                 Size 
                 Outer 
                 Inner 
                 Outer 
                 Arch 
                 Lateral 
                 Middle 
                 Apex 
               
               
                 Men 
                 Women 
                 Dimension 
                 Dimension 
                 Dimension 
                 Height 
                 Length 
                 Width 
                 Distance 
               
               
                   
               
               
                 JR 
                 4.5-6 
                 138 mm 
                 55 mm 
                 62 mm 
                 20 mm 
                 123 mm 
                 59 mm 
                 63 mm 
               
               
                 5.5-7 
                 6.5-8 
                 149 mm 
                 56 mm 
                 65 mm 
                 21 mm 
                 134 mm 
                 62 mm 
                 67 mm 
               
               
                 7.5-9 
                  8.5-10 
                 160 mm 
                 58 mm 
                 67 mm 
                 22 mm 
                 142 mm 
                 64 mm 
                 66 mm 
               
               
                  9.5-11 
                 10.5-12 
                 170 mm 
                 61 mm 
                 72 mm 
                 23 mm 
                 152 mm 
                 66 mm 
                 72 mm 
               
               
                 11.5-13 
                 12.5+ 
                 183 mm 
                 65 mm 
                 77 mm 
                 24 mm 
                 163 mm 
                 71 mm 
                 78 mm 
               
               
                   
               
             
          
         
       
     
         [0046]    Although the invention has been described with reference to the above example, it will be understood that modifications and variations are encompassed within the spirit and scope of the invention. Accordingly, the invention is limited only by the following claims.