US 7,726,903 B2Granted

Manhole system

AssigneeEast Jordan Iron Works, Inc.

InventorsKevin S. Vrondran, Jeremy I. Johnson, David Fuller

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Abstract

A manhole system that includes a manhole cover and a frame with at least one locking device for maintaining the manhole cover in place on the frame. The locking device is selectively movable between locked and unlocked positions to selectively engage the cover to hold the cover in place on the frame. The locking device may be rotatable between “locked” and “unlocked” positions about an axis perpendicular to the plane of the cover. The locking device may includes a plurality of cam locks that engage the outer circumferential edge of the cover and are configured to increasingly clamp down the cover against the frame with increasing rotation from “unlocked” position to “locked” position. A plurality of locks can be arranged around frame to engage the cover at different locations.

Claims4

Dependent claims

A manhole system comprising:

a manhole frame defining an manhole opening;
a manhole cover mounted to said frame covering said manhole opening, said manhole cover having an outer circumferential edge;
and
a locking mechanism mounted to said frame and selectively movable between a locked position operatively engaging said outer circumferential edge of said cover and an unlocked position operatively disengaged from said outer circumferential edge of said cover, said locking mechanism securing said cover on said frame when in said locked position, said locking mechanism permitting removal of said cover from said frame when in said unlocked positions;
said locking mechanism comprising:
a cam lock including an angled surface that gradually engages said outer circumferential edge, said cam lock being rotatable about an axis perpendicular to said cover, thereby increasingly clamping said cover onto said frame;
a plunger for maintaining the position of said cam lock;
and
a spring for activating said plunger;
wherein said frame further includes locking mechanism seats for receiving said locking mechanism, said locking mechanism seats being recessed within said frame;
and
wherein said outer circumferential edge has recessed annular flanges for receiving said locking mechanisms.

9 more elements

Dependencies are inferred from the claim text.