Patent ID: 9574652
Date: 2017-02-21
CPC Classifications: F16D,F16H

Claim:
1. A driving device used in a paper separation mechanism, comprising: an internal gear of cylindric shape, an inner sidewall of the internal gear protruding inward to form a guide block, a plurality of rear meshing teeth being protruded in a rear of the internal gear; an external gear of cylindric shape sheathed around the internal gear, the external gear having an outer ratchet around an outside surface of the external gear and a front ratchet protruded in a front of the external gear, a rear edge of the external gear protruding backward to form a plurality of resist blocks which are spaced from one another to form a plurality of activity grooves each between every two adjacent ones of the resist blocks, one sidewall of each of the resist blocks being designed with a slope, another side wall of each of the resist blocks being a vertical resist surface; a driving member having a substrate, a front face of the substrate protruding forward to form a plurality of front meshing teeth corresponding to the rear meshing teeth of the internal gear, the front face of the substrate protruding forward to form a plurality of pushing blocks which are arranged separately and around the front meshing teeth and corresponding to the activity grooves of the external gear; a shell of cylindric shape, an inner front face of the shell protruding backward to form a hollow cylinder, an outside surface of the hollow cylinder defining a guide groove of a spiral shape, the inner front face of the shell further protruding backward to form a rear ratchet arranged around the hollow cylinder in the shell and corresponding to the front ratchet of the external gear, a hole being opened through an outer wall of the shell, one side edge of the hole extending towards the other side edge of the hole to form a locking arm, a curvature of an outer surface of the locking arm being the same as a curvature of an outer surface of the outer wall of the shell, a free end of the locking arm projecting into the shell; and an elastic element; wherein the internal gear is sheathed around the hollow cylinder, the guide block is slidably located in the guide groove to guide the internal gear and the external gear to rotate and move back and forth in the shell, the free end of the locking arm resists against the outer ratchet of the external gear to stop the external gear from rotating counterclockwise, the elastic element is wound around the hollow cylinder and restrained between a front end of the internal gear and the inner front face of the shell, the driving member is rotatably mounted on a rear of the shell, the pushing blocks of the driving member are contained in the activity grooves of the external gear respectively and the rear meshing teeth of the internal gear mesh with the front meshing teeth of the driving member; wherein in use, the paper separation mechanism drives the driving member to rotate counterclockwise, each of the pushing blocks of the driving member slides along the slope of the external gear to push the external gear together with the internal gear to move forward, the guide block of the internal gear slides in the guide groove of the hollow cylinder to guide the internal gear to counterclockwise rotate and further move forward to press the elastic element, until the front ratchet of the external gear meshes with the rear ratchet of the shell, at this point a counterclockwise rotation angle of the driving member is directly proportional to a length of the slope of the external gear; then the elastic element releases an elastic potential energy to push the internal gear together with the external gear to clockwise rotate under the cooperation of the guide block and the guide groove and further move backward, the slope of the external gear pushes the pushing blocks of the driving member to make the driving member rotate clockwise, until the rear meshing teeth of the internal gear mesh with the front meshing teeth of the driving member, at this point a clockwise rotation angle of the driving member is directly proportional to a sum of the length of the slope and a length of the guide groove, so the clockwise rotation angle of the driving member is greater than the counterclockwise rotation angle.