Patent Publication Number: US-2021186716-A1

Title: Pyramidal prosthetic foot

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This PCT application claims priority to and the benefit of provisional patent application titled “Pyramidal Prosthetic Foot”, application number 201841026207, filed in the Indian Patent Office on 13 Jul. 2018. The specification of the above referenced patent application is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     The apparatus disclosed herein, in general, relates to a medical device, and in particular, relates to a prosthetic foot. 
     Amputees with a loss of a limb experience discomfort while using heavy prosthetic feet.  FIG. 1  (prior art) illustrates a prosthetic foot  101  with a heavy metallic connector  102 . The flat vertical composite section of the prosthetic foot  101  has reduced stiffness, and hence requires a large form factor metallic connector  102  to avoid over flexure. There is an unmet need for reducing the weight of metallic connectors and fittings in prosthetic feet. 
     SUMMARY OF THE INVENTION 
     The prosthetic foot disclosed herein addresses the above recited unmet need for reducing the weight of metallic connectors and fittings in prosthetic feet. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  (prior art) exemplarily illustrates a prosthetic foot with a heavy metallic connector. 
         FIG. 2  illustrates a prosthetic foot with a triangular composite support for supporting a lightweight metallic connector. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 2  illustrates a prosthetic foot with a triangular composite support  201  for supporting a lightweight metallic connector  203 . The prosthetic foot  201  comprises a hollow thin walled lightweight triangular top section  202  that is an integral part of a first leafspring  208  that originates from a top portion  205  to the toe  206  and a second leaf spring  204  that originates from the heel  207  to the toe  206 . Fiber continuity is established between the walls of the triangular composite support  202  by wrapping a prepeg around a triangular mold and removing the mold after curing the prepeg. The prosthetic foot  201  disclosed herein comprises a triangular carbon fiber composite section  202  that supports a small form factor metallic pyramidal connector  203 . The stiff triangular shape reduces deflection and does not require a heavy weight metallic connector for added strength. In an embodiment, a carbon fiber composite section of a closed square shape or a circle shape may be used instead of the triangular carbon fiber composite section  202 . However, the triangular carbon fiber composite section  202  requires the least amount of material for an optimised stiffness to weight ratio. The prosthetic foot  201  is manufactured using one or a combination of the following materials: carbon fiber composites, glass fiber composites, plastics, metal, etc. For example, the prosthetic foot  201  comprises carbon fiber in a thermosetting or thermoplastic matrix. 
     For example, unidirectional carbon fiber prepegs may be laid in a multiaxial layup sequence, and high temperature cured in a pressurized vacuum bagged environment in a metallic mold at a high temperature of 150 Celcius. 
     For example, the triangular carbon fiber composite section  202  may be of thickness in the range 2 mm to 5 mm, and preferably of 3 mm to 4 mm. The fiber layup sequence may comprise the following: Top woven 0/90, +45, −45, 0, 0, 0, 0, 0, 0, 0, 0−45,+45, Lower woven 0/90. The thickness of each prepeg layer may be in the 0.1 mm to 0.25 mm. To increase thickness, the number of prepeg layers may be increased. 
     Considerable weight savings are gained by the use of the triangular carbon fiber composite section  202 . For example, with a 5 cm walled equilateral triangular section, a weight saving of approximately 140 to 180 gm may be realized in the disclosed triangular section  202  in  FIG. 2  when compared to the heavy metallic connector section  102  illustrated in prior art  FIG. 1 . 
     The foregoing examples have been provided merely for explanation and are in no way to be construed as limiting of the prosthetic foot  201  disclosed herein. While the prosthetic foot  201  has been described with reference to various embodiments, it is understood that the words, which have been used herein, are words of description and illustration, rather than words of limitation. Furthermore, although the prosthetic foot  201  has been described herein with reference to particular means, materials, and embodiments, the prosthetic foot  201  is not intended to be limited to the particulars disclosed herein; rather, the prosthetic foot  201  extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims. While multiple embodiments are disclosed, it will be understood by those skilled in the art, having the benefit of the teachings of this specification, that the prosthetic foot  201  disclosed herein is capable of modifications and other embodiments may be effected and changes may be made thereto, without departing from the scope and spirit of the prosthetic foot  201  disclosed herein.