CIRCULAR RING HAVING END AND USED FOR RETAINING MANHOLE JOINT

PROBLEM TO BE SOLVED: To maintain pressure contact and fixation of an outside rubber ring part on a lateral side hole of a manhole for a long period by forming the title ring out of a stainless steel plate having projections and recessions which can be made to overlap in the longitudinal direction respectively and are juxtaposed alternately and by fitting guide bars transversely on the inside near to the opposite end parts of the ring. SOLUTION: A circular ring 1 having ends and shaped like a slender belt is formed so that it has V-shaped projections 1a and V-shaped recessions 1b provided alternately in a number of lines, e.g. three lines, in the longitudinal direction by folding a stainless steel plate with angles. An outside rubber ring part 5a of a manhole joint 5 is fitted in a lateral side hole 4a of a manhole 4 and the ring 1 is inserted and fitted inside this part. Then, the fore ends of hinge plates 9a and 9b are brought into contact with the interior angle faces of guide bars 2a and 2b, the plates 9a and 9b are opened in rotation so as to expand the loop of the ring 1 and thereby the rubber ring part 5a is brought into pressure contact with the lateral side hole 4a and fixed. Since the ring 1 has the shape of projections and recessions in a number of lines, according to this constitution, the tensile rigidity of the ring 1 itself is improved by the rib effect of the projections and the recessions and the pressure contact and fixation of the rubber ring part 5a can be maintained for a long period.