Abstract: A riser assembly for supporting a manhole cover is placed within a manhole frame for raising the height of the manhole cover to pavement level. The riser assembly includes a circular frame formed of a metal bar and has a locking ring attached thereto which extends vertically downwardly from the frame. A plurality of outwardly projecting tabs are formed in the locking ring and are adapted to engage the manhole frame to prevent upward movement of the riser. An expansion device expands the frame and locking ring outwardly whereby the locking ring abuttingly engages a vertical surface of the manhole frame to assist in locking the riser assembly to the manhole frame.

Abstract: A manhole cover support ring adapted to be placed within an existing manhole frame for raising the height of a manhole cover. A circular ring is formed by a generally vertically extending flange having an annular bar welded on its lower end which provides an inwardly extending manhole cover support ledge. The flange and bar are split at a common point on their peripheries. An expansion mechanism is pivotally mounted on and extends between the spaced ends of the bar formed by the split in the ring. The expansion mechanism includes a pair of eyebolts pivotally mounted on the spaced ends of the annular bar. The eyebolts each have a threaded shaft which is engaged in a respective threaded end of a tubular member. One of the threaded shafts has a right-hand thread and the other shaft is formed with a left-hand thread, whereby rotation of the tubular member in one direction will contract the ring sufficiently to place it within the manhole frame opening.

Abstract: A manhole cover elevating and support ring adapted to be placed within an existing manhole frame for raising the height of a manhole cover, and a method of installing the same. A circular ring is roll formed of metal bar stock with a predetermined size gap. An improved adjustable link is force-fitted within the ring gap to expand the ring outwardly into abutting clamping engagement with an annular wall of a manhole frame to securely mount the ring therein. The improved method includes the steps of radially compressing the ring and restraining the ring in this compressed position. The ring then is placed within a manhole frame opening. The restraining means is removed and the ring expands outwardly toward its normal uncompressed position, thereby clamping itself tightly against the manhole frame. The improved adjustable link and a spring biased keeper also may be installed within the ring gap to insure its clamping engagement with the manhole frame.

Abstract: A manhole cover support ring adapted to be placed within an existing manhole frame for raising the height of a manhole cover. A circular ring is formed by a generally vertically extending flange having an annular bar welded on its lower end which provides an inwardly extending manhole cover support ledge. The flange and bar are split at a common point on their peripheries. A toggle mechanism is pivotally mounted on at least one of the spaced ends of the bar and is operatively engageable with the other bar end. Actuation of the toggle mechanism to an over center position expands the ring flange into abutting relationship with a complementary circular portion of the manhole frame which forms the manhole opening to secure the support ring on the manhole frame. The toggle mechanism includes a pivotally mounted bolt which is threadably engaged with a portion of one of the toggle levers for adjusting the outward expansion limit of the ring.