Pin-shaft-middle-single-face-planed hinged connection

The invention discloses pin-shaft-middle-single-face-planed hinged connection. The pin-shaft-middle-single-face-planed hinged connection comprises a mono-lug seat, a pin shaft, a dual-lug seat, screws and the like. According to the pin-shaft-middle-single-face-planed hinged connection, the pin shaft is enabled to only penetrate through a pair of dual-lug seat pin shaft holes and then enabled to be fixedly connected with the mono-lug seat through the screws; one face, in contact with a screw head, of the middle part of the pin shaft is planed, the other face of the middle part of the pin shaft is still a cylindrical face, and a corresponding mono-lug seat contact face is machined to form a cylindrical concave face, so that automatic centering can be achieved when the pin shaft and the mono-lug seat are compacted even if center points of connection between the pin shaft and the mono-lug and dual-lug seats are in the axis of the pin shaft; required rotatable connection between the mono-lug seat and the dual-lug seat can be completely formed after the screws are screwed; the remarkable increase of difficulty of mounting in the prior art due to the fact that the pin shaft needs to simultaneously penetrate through all three pin holes of the dual-lug seat and the mono-lug seat, particularly when relatively-high-accuracy movable fit exists between the pin shaft and the pin holes and both the volume and weight of connected workpieces and the pin shaft are high is avoided.