Gantry three-coordinate measuring machine

The invention discloses a gantry three-coordinate measuring machine, and relates to the related technical field of three-coordinate measuring machines, the gantry three-coordinate measuring machine comprises a measuring platform and a gantry measuring seat arranged on the measuring platform, the gantry measuring seat is provided with a movable seat, the movable seat is provided with a telescopic measuring arm, the telescopic measuring arm is provided with a measuring head, and the measuring head is connected with the gantry measuring seat. A movable seat is arranged on the measuring platform, a cleaning assembly used for cleaning the measuring head is arranged on the movable seat, a cavity is formed in the measuring platform, two movable plates are installed in the cavity in a sliding mode, a clamping assembly used for clamping and fixing a measuring piece is arranged between the two movable plates, and a clutch assembly is arranged in the cavity. The clutch assembly comprises a motor fixedly installed on one