Fixed-length transmission unit

The utility model discloses a fixed-length transmission unit, and relates to the technical field of steel plate production. The device comprises a rack, a pinch roll mechanism and an encoder, the pinch roll mechanism comprises a group of seat plates, the group of seat plates are fixed on one side of the top of the rack, a lower pinch roll is fixed on the lower portion between the two seat plates, and an upper pinch roll is fixed on the upper portion between the two seat plates through a lifting mechanism. Two parallel carrier rollers are fixed to the side, away from the pinch roll mechanism, of the top of the rack through a carrier roller support, and a lower measuring wheel is fixed to the position, between the pinch roll mechanism and the carrier roller support, of the top of the rack through a first air cylinder. By reducing the width of the measuring wheel and matching with the lightening hole, the weight of the measuring wheel can be reduced, the flexibility of the measuring wheel can be improved, meanwh