Waterproof pit cover

Abstract

An improved access lid assembly is provided for a subsurface chamber used to service aircraft. A lift assembly is provided for elevating the lid upwardly from an opening in a surrounding mounting frame disposed atop the subsurface chamber while maintaining the lid in a horizontal disposition. A hinge assembly connects the lift assembly to the lid at a peripheral location thereon on the underside of the lid, without any connection to the peripheral edge of the lid. The hinge assembly allows the lid to rotate about a horizontal axis to an open position through an arc of at least ninety degrees. By avoiding any connection to the peripheral edges of the lid, an elastomeric, annular seal can be mounted to completely encircle the lid and provide a water-tight barrier about the access opening. The seal is mounted between the upper and lower surfaces of the lid within a groove, preferably with a dovetail connection, to securely grip and hold the seal upon the edge of the lid. Nevertheless, the use of an adhesive is avoided so that the seal can be easily removed and replaced when necessary. Also, the lift assembly is provided with a damper mechanism so as to protect the lift assembly from impacts and shocks that would otherwise result when the lid falls under the weight of gravity from an opened position to a horizontal disposition atop the access opening.