Gripping device for retaining a ring member supporting a manhole cover

In a manhole cover, a gripping device for retaining a ring member supporting the manhole cover, said supporting ring member comprising means for sitting on a peripheral horizontal shoulder of an upstanding tubular member mounted in a manhole, said gripping device comprising a plurality of rigid elbow-shaped members having a substantially horizontal arm radially secured inside said ring member and a substantially vertical pending arm extending below said ring member to internally face said tubular member, a screw member threadedly mounted through said vertical arm in the direction of said tubular member, a friction plate fixed to said screw member at one end thereof between said vertical arm and said tubular member, said screw member being rotatable in said vertical arm for tightening said friction plate on said tubular member to thereby frictionally retain said ring member to said tubular member and vertically fix said ring member on said shoulder relative to said tubular member, wherein said ring member and each elbow-shaped member are made of steel and welded together at one end of said horizontal arm, and wherein said friction plate is made of resilient plastic material for preventing said plate from upwardly sliding on said tubular member and from being unintentionally lifted from said shoulder.