| 摘要 |
PROBLEM TO BE SOLVED: To reduce a burden to a belt and restrict the belt from dislocating by engaging a dislocation detection rotary body with a dislocation control rotary body in an endless belt, displacing one end of the belt with the rotation, and making larger the frictional force between the blet and the detection rotary body than that between the detection rotary body and the control rotary body. SOLUTION: When a belt 3 is dislocated in the direction Z1, a dislocation detection rotary body 5 is made to abut on a control rotary body 6 against a force of a spring 12, and the body 6 rotates a string 7 against the force of spring 14 to take it up by the rotational drive force of the belt 3. Accordingly, an end of a variable roller 2 is displaced to the direction X2. A hole 8 has a size to receive the dislocation of a bearing 11, and a friction force between the belt 3 and the body 5 is larger than that between the body 5 and the body 6, while the belt 3 and the body 5 rotates integrally. When the dislocation force becomes larger the displacement of a roller becomes larger, and the belt 3 is started to the returned to the counter direction to the Z1 direction with the generation of displacement so that the belt 3 and the roller 2 resume their original conditions. |
