TWI411493B - - Google Patents

Abstract

This invention comprises a base at which a driving wheel is fixated and pivoted. The upper portion of the base has a support frame which is mounted and pivoted at the base via a shaft. The support frame is designed for a corresponding driven wheel; furthermore, the swinging motion of the support frame that utilizes a shaft as a support point is actuated by a correction device. The correction device is formed by placing two rolling components at interval of the support frame. The center axes of the two rolling components are parallel to each other; therefore, there is a constant distance between the two rolling components. There is a protrusion wheel disposed in between the two rolling components of the base. The center axis of the protrusion wheel is parallel to the center axis of the two rolling components. When the protrusion wheel rotates around its own center axis, the time difference generated by the centrifugal force pushes the two rolling components. Therefore, the support frame can perform simple harmonic motion based on the axial shaft as a fulcrum. As a result, a sand belt at the outside of the driving and driven wheels can reduce the condition of unilateral wear process. In addition, an electrical controlled correction device can perform brute-forced correction at the unilateral side of the sand belt where the support frame has a fulcrum for its axial shaft, even under the bilateral sand belt correction which is performed by the correction device; hence, changing the motion period of the simple harmonic motion.