Sole Construction for Elastic Energy Return

Abstract

In accordance with one implementation, a sole construction for energy rebound and storage includes one or more actuators located below primary pressure points of the foot. Each actuator may include a plunger element positioned above an elastic membrane. A cavity positioned below the elastic membrane may be vertically aligned with the plunger element and sized and configured to receive a portion of the membrane. The elastic membrane may be sized and configured to cradle and receive the plunger element so that when force is applied to the plunger element, the elastic membrane may stretch beneath the plunger toward the base of the cavity and store energy. A portion of this energy may be returned through the plunger element when the force is released and the elastic membrane springs back into place.

What is claimed is: 
     
         1 . A sole construction comprising:
 a foundation layer with a cavity defined therein;   an elastic membrane suspended across the cavity; and   a plunger element adjacent to the elastic membrane opposite the cavity, and vertically aligned with the cavity to stretch the elastic membrane under force toward a base of the cavity.   
     
     
         2 . The sole construction of  claim 1 , wherein an air gap is defined between a base of the cavity and the elastic membrane. 
     
     
         3 . The sole construction of  claim 1 , wherein the elastic membrane has a rim portion in contact with the foundation layer and a bucket portion suspended within the cavity when no external force is applied to the sole construction. 
     
     
         4 . The sole construction of  claim 3 , wherein the bucket portion of the elastic membrane is configured to receive a portion of the plunger. 
     
     
         5 . The sole construction of  claim 3 , wherein a base of the plunger rests within the cavity. 
     
     
         6 . The sole construction of  claim 1 , wherein the elastic membrane is pre-tensioned by a force applied to the plunger. 
     
     
         7 . The sole construction of  claim 6 , wherein stretching the elastic membrane compresses the foundation layer. 
     
     
         8 . An actuator comprising:
 an elastic membrane having a portion positioned within a cavity; and   a plunger element adjacent to the elastic membrane opposite the cavity, and vertically aligned with the cavity to stretch the elastic membrane under force toward a base of the cavity under.   
     
     
         9 . The actuator of  claim 8 , wherein the elastic membrane has a rim portion in contact with the foundation layer and a bucket portion suspended within the cavity when no external force is applied to the actuator. 
     
     
         10 . The actuator of  claim 8 , wherein the bucket portion of the elastic membrane is configured to receive a portion of the plunger. 
     
     
         11 . The actuator of  claim 8 , wherein a base of the plunger rests within the cavity. 
     
     
         12 . The actuator of  claim 8 , wherein the elastic membrane is pre-tensioned. 
     
     
         13 . The actuator of  claim 12 , wherein stretching the elastic membrane compresses the foundation layer. 
     
     
         14 . A method of providing energy return to a user comprising:
 applying a force to a plunger to stretch an elastic membrane toward a base of a cavity opposite the elastic membrane; and   removing the force to allow the elastic membrane to return to an original position and return energy through the plunger to the user.   
     
     
         15 . The method of  claim 14 , wherein applying the force to the plunger stretches the elastic membrane into an air gap defined between the base of the cavity and the elastic membrane. 
     
     
         16 . The method of  claim 14 , wherein the elastic membrane has a rim portion in contact with the foundation layer and a bucket portion suspended within the cavity when no external force is applied to the plunger. 
     
     
         17 . The method  16 , wherein the bucket portion of the elastic membrane is configured to receive a portion of the plunger. 
     
     
         18 . The method of  claim 16 , wherein a base of the plunger rests within the cavity. 
     
     
         19 . The method  claim 14 , wherein the elastic membrane is pre-tensioned. 
     
     
         20 . The method  claim 19 , wherein stretching the elastic membrane compresses the foundation layer.