GRIPPING DEVICE FOR RETAINING A RING MEMBER SUPPORTING A MANHOLE COVER

摘要

The present invention is directed to a gripping system for holding a supporting ring member adapted to support a manhole cover in a tubular member having a peripheral horizontal shoulder. The gripping system has a plurality of rigid elbowshaped members internally secured inside the ring member. The elbow-shaped members have a horizontal arm radially extending inside the ring member and a substantially vertical pending arm extending below the ring member and adapted to internally face the tubular member. A screw member is threadedly mounted through the vertical arm in the direction of the tubular member. The screw member is provided with a friction plate fixed at one end between the vertical arm and the tubular member for tightening the friction plate on the tubular member and for frictionally retaining the ring member to the tubular member. The friction force is adapted to vertically fix the ring member relative to the tubular member.