CENTER PUSHING END-TO-END CIRCULAR RING FOR MANHOLE COUPLING

PROBLEM TO BE SOLVED: To restrain occurrence of corrosion, facilitate butting works, prevent both ends of an end-to-end circular ring from being dislocated in the width direction, by letting a hinged type expansion tool be opened and actuated, sliding the end-to-end circular ring in the opposite directions so as to allow both its end parts to be butted, and pressing an outside rubber ring part in conatct with the side surface pore of an manhole. SOLUTION: A bridging wooden angle member 6 is installed at a place below the intermediate portion of an end-to-end circular ring acting as an expanding tool from the outside of a manhole 3. A jack 7 is installed at the center of the wooden angle member 6, and hinged plates 9a and 9b are installed at the tip end of the shaft pole of the jack 7. Tip ends of the hinged plates 9a and 9b are placed onto the inner corner surface of guide bars 2a and 2b, and the hinged plates 9a and 9b are opened so as to be rovolved with the shaft pole 8 actuated. This constitution thereby allows both ends of the end-to-end circular ring 1 to be slid to the opposite directions, and both the ends are thereby butted. By this constitution, the end-to-end circular ring 1 is expanded so as to be fixed without being returned back, and also without coming out, and it is thereby pressed in contact with the surface pore of the man hole 3.