Passive shock absorber for treadmill

Abstract

A passive shock absorber for a treadmill includes a tall damping member and a short stopping member for supporting the tall damping member. Both the tall damping and the short stopping members have a top, a bottom and a spring stiffness, respectively. The tall damping and the short stopping member are combined together and are mounted in the treadmill. The passive shock absorbers are adapted to mount under a flat stationary member on which a person walks, runs or jogs. The top of the tall damping member abuts the flat stationary member. Consequently, the tall damping member can absorb impacts on the person's feet and the short stopping member will stop a compression of the tall damping member as the tall damping member is suddenly deformed and compressed.

What is claimed is:  
     
         1 . A passive shock absorber for a treadmill having a tread frame and a moving tread assembly, the moving tread assembly having a flat stationary member with a bottom, and the passive shock absorber adapted to be mounted between the thread frame and the bottom of the flat stationary member and comprising: 
 at least one tall damping member having a spring stiffness, a damping characteristic, a top, a bottom and a height and the at least one tall damping member being for dissipating impact energy on a person's feet; and    at least one short stopping member combined with the at least one tall damping member together and the at least one short stopping member having a spring stiffness, a damping characteristic, a top, a bottom and a height and the at least one short member being for stopping a compression of the at least one tall damping member;    wherein the spring stiffness of the at least one tall damping member is larger than the spring stiffness of the at least one short stopping member and the height of the at least one tall damping member is greater than the height of the at least one short stopping member.    
     
     
         2 . The passive shock absorber as claimed in  claim 1 , wherein the at least one short stopping member is made of viscoelastic material for dissipating impact energy on the person's feet as the top of the at least one short stopping member abuts the bottom of the flat stationary member.  
     
     
         3 . The passive shock absorber as claimed in  claim 1 , wherein the passive shock absorber has 
 one tall damping member having a cylindrical shape, an axial center and an outer periphery; and    one short stopping member attached to the outer periphery of the tall damping member and having a cylindrical shape and an axial through hole, the outer periphery of the tall damping member being received in the axial through hole of the short stopping member.    
     
     
         4 . The passive shock absorber as claimed in  claim 1 , wherein the passive shock absorber has 
 one tall damping member having a rectangular parallelepiped shape with two opposite long sides; and    two short stopping members respectively attached to the long sides of the tall damping member, each short stopping member having a rectangular parallelepiped shape and attached to a corresponding one of the long sides of the tall damping member.    
     
     
         5 . The passive shock absorber as claimed in  claim 1 , wherein the passive shock absorber has 
 one short stopping member having a cylindrical shape, an axial center and an outer periphery; and    one tall damping member attached to the outer periphery of the short stopping member and having a cylindrical shape and an axial through hole, the outer periphery of the short stopping member being received in the axial through hole of the tall damping member.    
     
     
         6 . The passive shock absorber as claimed in  claim 1 , wherein the passive shock absorber has 
 one short stopping member having a rectangular parallelepiped shape with two opposite long sides; and    two tall damping members respectively attached to the long sides of the short stopping member, each tall damping member having a rectangular parallelepiped shape and attached to a corresponding one of the long sides of the short stopping member.    
     
     
         7 . The passive shock absorber as claimed in  claim 3 , wherein a mounting hole is axially defined through the top to the bottom of the tall damping member.  
     
     
         8 . The passive shock absorber as claimed in  claim 4 , wherein a mounting hole is defined through the top to the bottom of the tall damping member.  
     
     
         9 . The passive shock absorber as claimed in  claim 5 , wherein a mounting hole is axially defined through the top to the bottom of the short stopping member.  
     
     
         10 . The passive shock absorber as claimed in  claim 6 , wherein a mounting hole is defined through the top to the bottom of the short stopping member.