Patent ID: 6893383

Claim:
A stepper comprising a main frame including a base and two stands respectively upwardly extending from two opposite sides of a front portion of the base, two swing arms respectively pivotally mounted to a rear portion of the base, two restitution structures respectively pivotally mounted to a bottom of a corresponding one of the two swing arms for providing a restitution force to the corresponding swing arm, each swing arm having a pivot structure mounted in a rear end of each of the two swing arms and an endless strap sleeved thereon, a drive shaft extending through the pivot structure of each of the two swing arms for supporting the two swing arms and driving the endless strap of each of the two swing arm, multiple supports upwardly extending from the rear portion of the base for supporting the drive shaft, a motor mounted on the base for driving the drive shaft, said restitution structures including an air spring and rack, the air spring having a first end pivotally connected to the base and a second end pivotally connected to the bottom of a corresponding one of the two swing arms, the rack having a first end slidably mounted to the base and a second end pivotally connected to the bottom of the corresponding swing arm, the first end of each of the two restitution structures having two opposite sides respectively slidably received in a rectangular casing that is laterally attached to the base.