A concealed suspension ceiling system advantageously uses a `T` bar grid network used for lay-in ceiling panels. Butterfly clips are secured to upper beads of the `T` bar grid network allowing torsioning springs to releasably maintain the panels suspended beneath the grid. The system can be used for entirely new installations or used in a retrofit application.

A system for boarding up a store front window, and more specifically a corner bracket for use in removably supporting a panel respective an opening formed by a store front frame having corners. The panel temporarily closes the opening while avoiding damage to the frame, and preventing intrusion through the store front frame. The corner bracket has spaced parallel flanges connected by perpendicular load bearing wall members. One bracket is received at each corner of the store front frame and the load bearing wall members bear against adjacent frame members that form a corner. One of the flanges engage an interior surface of the frame while the opposed flange is attached to the panel. This causes the corner bracket to urge the panel against the exterior wall surface of the frame. The panel can be of an area greater than the area defined by the inner periphery of the frame to bring the marginal edge of the panel into engagement with the exterior frame face. Hence the spaced parallel flanges places the perpendicular load bearing wall members in tension and resists both lateral and outward movement of the temporary panel away from the frame. Additionally, this arrangement hides the corner brackets from outside view and therefore nothing is revealed exteriorly of the enclosure that would enable a pedestrian to determine the details of the construction.

According to the present invention, a new suspended ceiling system is possible of the type having a plurality of removable panels which are supported below a grid network. The grid network comprises structural elements interconnected by junction members with the cells of the grid network sized to receive a panel about the periphery thereof. These structural members cooperate with framed panel members to accurately align adjacent panels and position them at a certain height below the grid network. Access to the area above the panels is easily obtained by removal of any of the panel members. Each panel is urged into abutting contact with the grid network to provide a seal therewith such that the area above the ceiling may be used as a return air plenum. The particular frame member for the panels facilitates mechanical connection about and to the body member of the panel and also simplifies removal of the panel.

A grid system for torsion spring mounting of aluminum-framed panels is provided which includes a plurality of main grid beams and spacer bars. The main grid beams support a side load mounting clip formed with a slot in the side of the side load mounting clip to engage a torsion spring held by a spring retainer clip such that the panel is supported by the torsion spring. Disengagement of the torsion springs lowers the panels and permits access to the ceiling grid system above the panel members. In a preferred embodiment, the panel has a multifaceted profile including an edge surface that abuts a corresponding edge surface on an adjacent panel. The peripheral edges of the adjacent panel members diverge above the abutting edge surfaces to accommodate either the alignment fin or the tab of the tile stop and diverge below the abutting edge surfaces to form a reveal.