Measuring tool for rapidly measuring diameter of conical inner cavity casing

The invention discloses a measuring tool for rapidly measuring the diameter of a conical inner cavity casing; two plane positioning blocks a and b are fixed at two ends of a body seat, and a measuringrod b is a fixed measuring rod and is arranged at the right side of the body seat; a support is arranged in a cavity of the body seat, a support block is arranged in a cavity of the support, and themeasuring rod a and the measuring rod c are fixed to integrally form a movable measuring rod; a flange linear bearing and a bushing are respectively fixed at two ends of the support; a pull rod is fixed on the support block; a compression spring is arranged on the pull rod; a handle and the pull rod are vertically fixed; a sliding rod is fixed on the support block; two spherical deep groove bearings and two baffle plates arranged on the support slide in a gapless manner; a bracket is arranged on the body seat in the same direction as the movable measuring rod and is fixed with the body seat through welding; and a sprin