Abstract: A manhole cover assembly configured to behave as a relief valve in an explosion event, opening so that fluid, such as air or explosive gas, may vent from an underground area. The manhole cover assembly may include a manhole cover and a frame, and may be configured to limit movement of the manhole cover with respect to the frame in response to increased pressure on the manhole cover. In one embodiment, the manhole cover may include legs having angled surfaces adapted to substantially center or guide the manhole cover in the frame while the manhole cover displaces to release pressure. In another embodiment, one or more legs may be at least one of pivotable with respect to the manhole cover and slidable within the manhole cover to enable configuring the manhole cover between a restraint mode and a removal mode.

Abstract: A manhole cover assembly includes a frame that includes a central opening and a safety stop portion, and a cover hingedly attached to the frame such that the cover is pivotable between a closed position covering the central opening and an open position providing access to the central opening. A safety device is connected to the frame and the cover for locking the cover in the open position. Movement of the cover to the open position automatically moves the safety device to a locked position in which said safety device engages the safety stop portion and prevents movement of the cover to the closed position. When the cover is open, the safety device is manually movable between the locked position and an unlocked position in which the safety device is disengaged from the safety stop and permits movement of the cover to the closed position.

Abstract: A manhole cover assembly includes a frame that includes a central opening and a safety stop portion, and a cover hingedly attached to the frame such that the cover is pivotable between a closed position covering the central opening and an open position providing access to the central opening. A safety device is connected to the frame and the cover for locking the cover in the open position. Movement of the cover to the open position automatically moves the safety device to a locked position in which said safety device engages the safety stop portion and prevents movement of the cover to the closed position. When the cover is open, the safety device is manually movable between the locked position and an unlocked position in which the safety device is disengaged from the safety stop and permits movement of the cover to the closed position.

Abstract: A manhole cover assembly includes a frame defining an access opening, first and second mounting posts extending from the frame, and a cover for covering the access opening. The cover includes first and second mounting recesses that pivotally receive the first and second mounting posts respectively, such that said cover is movable between an open position and a closed position by rotating the recesses about the posts. At least one of the recesses includes a locking groove that aligns with the post when the cover is moved to an open position to lock the cover in the open position.

Abstract: A one-piece, unitary manhole cover has dual lifting ports that drain through the outer circumferential edge of the cover. A lifting channel runs from the interior of the upper face out to the outer circumferential edge. A lifting bar spans the lifting channel and defines an ergo lifting port and a pry bar lifting port. Both the ergo lifting port and the pry bar lifting port drain through the outer circumference of the manhole cover.

Abstract: A swing-out manhole cover assembly having at least one ramp to facilitate opening and closing the cover. The manhole cover assembly includes a frame, a cover, a swing assembly and at least one ramp. As the cover swings open away from the frame about the swing assembly, the ramp imparts linear translation to the cover separating the cover from the frame slightly. As the cover swings back to close the manhole cover, the ramp reverses the linear translation and the cover returns back to the frame. A spring may be included to bias the cover in the closed position.

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.

Abstract: A manhole cover assembly includes a frame defining an access opening, first and second mounting posts extending from the frame, and a cover for covering the access opening. The cover includes first and second mounting recesses that pivotally receive the first and second mounting posts respectively, such that said cover is movable between an open position and a closed position by rotating the recesses about the posts. At least one of the recesses includes a locking groove that aligns with the post when the cover is moved to an open position to lock the cover in the open position.

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.

Abstract: A one-piece, unitary manhole cover has dual lifting ports that drain through the outer circumferential edge of the cover. A lifting channel runs from the interior of the upper face out to the outer circumferential edge. A lifting bar spans the lifting channel and defines an ergo lifting port and a pry bar lifting port. Both the ergo lifting port and the pry bar lifting port drain through the outer circumference of the manhole cover.