Quick Change Shock Mitigation Outsole Insert with Debris Shield

Abstract

An article of footwear has a shock absorbing insert placed between the insole and the outsole thereof, for example at the heel. The insert includes a spring carrier having upper and lower portions, each having a plurality seats for receiving a respective ends of respective coil springs. Each of the springs extends between said upper and lower portions and is captured therebetween. A magnetic spring supplements the mechanical springs. The springs and carrier are protected from environmental elements and abrasive particles by a debris shield.

I claim: 
     
         1 . An article of footwear comprising
 an outsole,   an inner sole, and   a shock absorbing insert disposed between the outsole and the inner sole, said insert comprising   a spring carrier having upper and lower portions, each of said portions having a plurality seats for receiving a respective ends of respective mechanical compression springs,   a like plurality of mechanical compression springs, each extending between said upper and lower portions and being captured therebetween,   a single magnetic spring disposed between the mechanical compression springs, said magnetic spring comprising a pair of permanent magnets of opposed polarity, and   a debris shield for containing said spring carrier and said springs, said debris shield being adapted to protect said springs from environmental elements and abrasive particles.   
     
     
         2 . The article of footwear of  claim 1 , wherein each of the mechanical compression springs is a coil spring and each of the spring seats has a double wall defining an annular volume for securely holding an end of a respective coil spring. 
     
     
         3 . The article of footwear of  claim 1 , further comprising snap-in structure for holding the insert in the footwear. 
     
     
         4 . The article of footwear of  claim 1 , wherein the upper and lower portions of the spring carriers are integrally interconnected by a living hinge. 
     
     
         5 . The article of footwear of  claim 1 , wherein the seats are molded integrally with and as part of the spring carrier. 
     
     
         6 . The article of footwear of  claim 1 , wherein the insert further comprises upper and lower magnet canisters formed in the plate, amid the mechanical compression spring seats. 
     
     
         7 . The article of footwear of  claim 6 , wherein the canisters are aligned on an axis which lies on the vertical center plane of the insert. 
     
     
         8 . The article of footwear of  claim 7 , wherein the mechanical compression spring seats are arranged around the canisters, at a uniform radial distance from said axis. 
     
     
         9 . The article of footwear of  claim 1 , wherein said magnets are rare earth permanent magnets having a magnetic strength of at least 35 mgo. 
     
     
         10 . The article of footwear of  claim 1 , wherein the insert further comprises a debris shield to protect the springs and magnets from water, dirt and abrasive particles. 
     
     
         11 . The article of footwear of  claim 11 , wherein the debris shield has at least one pull tab that a user can grasp to remove or replace the insert. 
     
     
         12 . The article of footwear of  claim 1 , further comprising a footbed between the outsole and the insole. 
     
     
         13 . The article of footwear of  claim 1 , wherein the insert is disposed in a recess in the outsole, beneath the footbed. 
     
     
         14 . The article of footwear of  claim 1 , wherein the insert is disposed in a recess in the outsole, above the footbed. 
     
     
         15 . A shock-absorbing spring insert assembly for footwear, said assembly comprising
 a spring carrier having upper and lower portions, each of said portions having a plurality seats for receiving a respective ends of respective mechanical compression springs,   a like plurality of mechanical compression springs, each extending between said upper and lower portions and being captured therebetween, and   a magnetic spring disposed between the magnetic compression springs, said magnetic spring comprising a pair of permanent magnets of opposed polarity,   wherein said upper and lower portions of the spring carrier are interconnected by a hinge so that the spring carrier can be opened to permit servicing or replacement of the springs,   whereby characteristics of the insert may be adjusted for different wearers or to control supination and/or pronation of a wearer's foot.   
     
     
         16 . The insert assembly of  claim 15 , wherein the hinge is a living hinge formed integrally with said upper and lower portions. 
     
     
         17 . The insert assembly of  claim 15 , further comprising a debris shield for containing said spring carrier and said springs, to protect said mechanical and magnetic springs from environmental elements and abrasive particles, said debris shield comprising a flexible envelope having an opening at one side into which the spring assembly can be inserted, prior to installation of the spring assembly into the footwear. 
     
     
         18 . The insert assembly of  claim 17 , wherein the flexible envelope is made of rubber or an elastomeric polymer. 
     
     
         19 . The insert assembly of  claim 17 , wherein the debris shield has formed thereon at least one pull tab to facilitate installation and removal of the spring assembly. 
     
     
         20 . The insert assembly of  claim 15 , wherein the mechanical and compression springs are selected to as to together support a load in the range of 100-600 pounds without binding.