Elongation measuring device

摘要

An elongation measuring device 10 measures an elongation in a timing belt 4 included in a driving device 1 provided with a drive roller 2 . The elongation measuring device 10 is provided with an encoder 11 and a microphotosensor 12 . A present angular position of the drive roller 2 measured at a present-stage measuring cycle and a past angular position of the same measured at a past-stage measuring cycle. The difference between the present and the past angular position is due to the elongation of the timing belt 4 . An elongation in the timing belt 4 is estimated on the basis of the difference between the present and the past angular position. Time when the timing belt 4 may possibly break is forecast on the basis of the elongation in the timing belt. The worn out timing belt 4 is replaced with a new one before the same breaks.