Quick connecting device suitable for loading arm of LNG loading and unloading vehicle

The utility model discloses a quick connecting device suitable for a loading arm of an LNG loading and unloading vehicle. The quick connecting device comprises a pipeline, a butt flange, a conical guide pipe, a pressing disc, an operating handle, a locking device, a spring, a fixed disc and a sliding roller. The conical guide pipe is in butt joint with the pipeline in a welding mode, and in the butt joint process, the guide effect can be achieved; the butt flange and the fixed disc are fixedly connected with the pipeline in a welding manner; the pressing disc is mounted on the pipeline and is coaxial with the pipeline; the operating handle is fixedly connected with the pressing disc, and the pressing disc is driven to rotate on the pipeline by pulling the operating handle; the locking device is sleeved with a spring and is matched with the pressing disc through a sliding roller; when the locking disc rotates anticlockwise, the locking device opens the locking clamping jaw under the elastic force action of the