Short carrier roller type belt running speed detection device

A short carrier roller type belt running speed detection device is characterized by comprising a carrier roller shaft, bearing blocks, a speed encoder, a lower support and L-shaped fixing plates. One end of the carrier roller shaft is connected with the speed encoder by a coupler, the carrier roller shaft is mounted on the bearing blocks fixed on the lower support, the lower support can be supported on ground by adjustable supporting legs, and two ends of the lower support are connected with the L-shaped fixing plates by bolts and are fixed onto a conveying belt frame. A carrier roller is mounted on the lower side of a lower belt and is lower in stress as no load is arranged on the lower belt the length of the carrier roller is only about 1/4 of the width of the belt, and the carrier roller only contacts with the middle of the wide surface of the belt, so that dead weight of the carrier roller is reduced greatly. Accordingly, the stress condition of the carrier roller is substantially improved, the carrier ro