U-shaped frame size measuring tool

The utility model discloses a U-shaped frame dimension measuring tool, which belongs to the dimension measuring field, and comprises an operation plate, baffle plates are fixed on two sides of the top of the operation plate, two clamping plates are slidably connected between the two baffle plates on the top of the operation plate, and the two clamping plates are symmetrically arranged. A rotating rod is rotationally connected to the center position of the top of the operation plate, a gear is fixed to the outer side of the rotating rod, racks are fixed to the positions, corresponding to the gear, of the inner sides of the two clamping plates, a blocking assembly is further installed on the outer side of the rotating rod and used for blocking the clamping plates from rebounding and moving, and the blocking assembly comprises a pressing column; the rotating rod is sleeved with the pressing column, a ratchet wheel is fixed to the bottom of the pressing column, and a first spring is installed between the gear and