Locking cover for a soffit manhole

Abstract

A locking cover is provided for a manhole or other access opening formed in a soffit or the like, such as an access manhole formed in an otherwise enclosed overhead cell or chamber within a concrete overpass or bridge structure of a light rail or highway transportation system. The locking cover includes an upper section defined by multiple segments sized to fit upwardly through the manhole and then assemble to define a peripheral rim for seating upon an upper soffit surface generally circumscribing the manhole. A lower section includes a peripheral rim for substantially seated engagement with a manhole-circumscribing lower soffit surface, and carries a lock unit for releasible connection with a lock bolt depending from the assembled upper section. The lock unit is positioned within an access-restricting containment sleeve to resist and / or discourage tampering.

Description

BACKGROUND OF THE INVENTION [0001] This invention relates generally to an improved manhole cover and related method of installation, particularly for use in lockably closing a manhole or other access opening formed in an overhead soffit structure to restrict access to an otherwise enclosed overhead cell or chamber formed, e.g., within a concrete overpass or bridge structure of a light rail or highway transportation system or the like. More specifically, the locking cover of the present invention is designed for securely closing the soffit manhole in a manner that substantially prevents unauthorized access to the overhead cell or chamber by unauthorized persons. [0002] Modern overhead structures such as concrete overpasses and bridges used in rail and highway transportation systems often incorporate internal, substantially enclosed cells or chambers which are accessed from below through one or more hatch or access openings such as circular manholes formed in an overhead soffit struct...

AI Technical Summary

Benefits of technology

[0007] The lower section also has a generally circular shape defining said peripheral rim for engaging a lower or underside surface of the peripheral margin of the manhole. A bolt port formed in the lower section is positioned for coaxial alignment with the bolt port formed in the upper section, for receiving a support bolt passed upwardly therethrough and threadably engaged with the nut for temporarily connecting and aligning the lower section in suspended relation with the upper section. In this orientation, the lock post on the upper section protrudes downwardly through a post port formed in the lower section and is disposed within the depending containment sleeve carried by said lower section. The lock unit is slidably fitted upwardly into the containment sleeve for locked engagement with the lock post. Shims may be interposed between the lock unit and the lower section for positioning and retaining the lower section with the peripheral rim thereon relatively tight seated engagement with the underside peripheral margin of the manhole.

[0008] In the preferred form, the lock unit comprises a generally cylindrical lock cartridge having an armored steel construction, with a reciprocal core pin movable between a locked position advanced into locking engagement with the lock post, and a key-actuated unlocked position retracted from the lock post. A keyway is exposed laterally through a vertically elongated slot formed in the containment sleeve for key-actuated unlocking and removal of the lock unit, in the event that access to and through the manhole is desired. At other times, the containment sleeve substantially conceals or disguises the location of the keyway from view to discourage attempted tampering. The secondary barrier may comprise an arcuate wall depending from the lower section in relatively short laterally spaced relation from the containment sleeve and the keyway slot formed therein. This secondary barrier thus restricts and minimizes the available space for keyway access, and thereby prevents or restricts access to the keyway by most tools of the type typically employed by unauthorized persons to tamper with or damage the lock unit.

Problems solved by technology

Accordingly, such slide-fit manhole covers have provided little or no effective security against slide-out removal by unauthorized persons desiring to use the overhead cells or chambers as living quarters and / or for other nefarious activities including but not limited to damaging the overpass or bridge structure or the equipment and facilities carried thereby.

Alternative manhole cover designs such as wedge-fit arrangements have been provided in an effort to discourage unauthorized removal from the access opening, but these too have been susceptible to unauthorized tampering and removal by enterprising individuals.

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