| 摘要 |
A lighting fixture for sealed emvironments including cleanroom and containment environments. There is described a recessed, ceiling-mounted fixture which has a one-piece, seam-welded housing, and which carries swing out mounts. The fixture is further characterized by an improved system by which its lens assembly, which employs a specially-shaped lens frame and a uniquely-contoured, one-piece gasket, is doubly sealed, firmly and evenly. against the fixture housing and the ceiling in which the fixture is mounted. A unique and functionally significant feature of the fixture is the provision of a support fulcrum bracket which is positioned radially inwardly of the fixture securment screws. The support fulcrum bracket functions, in conjunction with a cooperating screw fastener, to reverse the fulcrum point of fixture constructions of this type, thereby drawing the lens frame and gasket system in consistent and reliable contact with the ceiling structure. The bracket also serves to ensure the preservation and retention of a planar configuration of the lens-carrying assembly, while effectively eliminating over-torque problems which otherwise commonly occur. Thus, the present invention ensures improved, positive, perimetric seals with the housing and at the ceiling. Such seals are not currently not available, to this extent, in sheet metal lighting fixtures being used for these applications.
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