Retractable life buoy

The utility model discloses a retractable life buoy, a serial communication port, be excellent curved section of inflating and be the regulation section that the minor arc is capable with whole including whole, the section of inflating with adjust the section and link up and constitute circularly, adjust being provided with diameter adjustment mechanism in the section and can realizing the big or small regulation of the circular diameter of life buoy, diameter adjustment mechanism is including fixing the interior pipeline section that extends forward at the section of inflating one end tip and cisoid, and still including fixing the outer pipeline section that extends forward at the section of inflating other end tip and cisoid, port department in outer pipeline section outer end rotationally is provided with an adjusting nut, and the adjusting nut internal diameter is lighter than outer pipeline section inner chamber, just interior pipeline section circumference surface was provided with external screw thread