| 摘要 |
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.
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