Crank structure for treadmills

Abstract

An improved crank structure for treadmills, each of the treadmills has two pedals for a user to step, the pedals respectively connect on one of their ends with the periphery of a rotary wheel, and are linked with cranks respectively on the front and the rear sides of the rotary wheel, the cranks are connected on their internal end portions with the center of the rotary wheel, the cranks are provided each with a first section which has an included angle with the vertical diametric line of the rotary wheel, at the tailing end of the first section, there is a bent section for connecting with the center of the rotary wheel. A user using such a treadmill needs only to exert a small force at the uppermost position of the rotary wheel for stepping; this can prevent probable damage of exercising.

1 . An improved crank structure for treadmills, each of said treadmills has two pedals for a user to step, said pedals respectively connect on one of their ends with the periphery of a rotary wheel, and are linked with cranks respectively on the front and the rear sides of said rotary wheel, said cranks are connected on their internal end portions with the center of said rotary wheel, said crank structure is characterized by that: said cranks are provided each with a first section which has an included angle with the vertical diametric line of said rotary wheel, at the tailing end of said first section, there is a bent section for connecting with the center of said rotary wheel.  
     
     
         2 . An improved crank structure for treadmills as claimed in  claim 1 , wherein, said first sections of said cranks each has an included angle of within 90° with said vertical diametric line of said rotary wheel.  
     
     
         3 . An improved crank structure for treadmills as claimed in  claim 1 , wherein, said first sections of said cranks each is perpendicular to the corresponding one of said bent sections.