Manhole grade adjusting ring and method
First Claim
Patent Images
1. A manhole grade adjusting ring for installation in a manhole frame to raise the level of a manhole cover, comprising:
- a ring including circular bar and skirt portions, said bar portion having a base surface for being supported on the manhole frame and a platform surface above said base surface for supporting the manhole cover, and said skirt portion extending above said platform surface;
wherein said ring is split so as to define first and second ends adjacent to one another;
an expansion lock having a first end, a second end and a V-shaped expansion joint between said first and second ends;
means for securing the first end of the expansion lock to the first end of the ring with the expansion lock bridging the first and second ends of the ring and the V-shaped expansion joint pointing inward of said ring; and
adjustable means for securing the second end of the expansion lock to the second end of the ring, said adjustable means allowing said second end of the lock to be releasably secured to the second end of the ring at different positions on said second end of the ring so as to vary the position of the first and second ends of the ring relative to one another.
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Abstract
A manhole grade adjusting ring has an adjustable diameter with a V-shaped expansion lock bridging the ends of the ring. The expansion lock has radial flanges which are adjustably pinned in slots in the ends of the ring after the ring is expanded or contracted to fit a particular manhole frame using an expansion/contraction tool. The "V" is then hammered to expand the diameter of the ring so as to form a tight friction fit between the ring and the manhole frame.
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Citations
15 Claims
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1. A manhole grade adjusting ring for installation in a manhole frame to raise the level of a manhole cover, comprising:
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a ring including circular bar and skirt portions, said bar portion having a base surface for being supported on the manhole frame and a platform surface above said base surface for supporting the manhole cover, and said skirt portion extending above said platform surface; wherein said ring is split so as to define first and second ends adjacent to one another; an expansion lock having a first end, a second end and a V-shaped expansion joint between said first and second ends; means for securing the first end of the expansion lock to the first end of the ring with the expansion lock bridging the first and second ends of the ring and the V-shaped expansion joint pointing inward of said ring; and adjustable means for securing the second end of the expansion lock to the second end of the ring, said adjustable means allowing said second end of the lock to be releasably secured to the second end of the ring at different positions on said second end of the ring so as to vary the position of the first and second ends of the ring relative to one another. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of adjusting the grade of a manhole, comprising:
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approximately sizing a variable diameter manhole grade adjusting ring to a manhole frame; expanding or compressing the manhole grade adjusting ring to a diameter slightly less than the diameter of said manhole frame; placing said manhole grade adjusting ring in said manhole frame; securing an expansion lock to the manhole grade adjusting ring so as to fix the expanded or compressed diameter of said manhole grade adjusting ring to provide a loose fit of the ring in the manhole frame; and expanding the expansion lock to increase the diameter of the manhole grade adjusting ring so that the ring bears against the frame to produce a tight friction fit between the ring and the frame. - View Dependent Claims (14, 15)
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Specification