Four-bar-link hinges from Weber Knapp keep cover plates flush with the floor.
Four-bar-link hinges from Weber Knapp keep cover plates flush with the floor.

Custom concealed hinges from Weber Knapp, Jamestown, N.Y. (www.webberknapp.com), keep utility cover plates flush with floors in convention centers. The covers conceal a series of trenches containing Walker Systems, West Hartford, Conn. (www.wiremold.com), power cables and connectors. The approach eliminates the tripping hazards of exposed hinges and electrical cables cluttering the floor. And it cleans up unsightly electrical cables dangling from ceilings.

Weber Knapp opted for a four-bar-link hinge because the flush-with-floor spec ruled out straight-pivot designs. The hinges move covers upward until they clear floor level, then swing them away for easy access to trenches. Covers are up to 6 ft long and weigh about 100 lb. Offsetting the weight is a counterbalancing spring and friction-control system. It lets one person open a cover with minimal effort and holds the cover in position until closing.

-- Lawrence Kren