| 摘要 |
Detachable chevron-shaped panels that fit within chevron-shaped apertures in the cover of an exit sign. The panels are dimensioned to fit integrally into the apertures in order to withstand years of stress, temperature changes, and wear and tear but continue to perform in a light-fast and reliable manner. Yet they may be easily installed from the exterior of the exit sign, with minimum risk that they will fall into the interior during installation. Surprisingly, the present devices permit such easy installation without the need to use conventional "slide 'n' snap" exit sign arrow fasteners that usually allow reliable installation but have proven to be destructive of a secure fit and light fastness. The panel accomplishes this by employing at least three tabs positioned in a certain manner about the perimeter of each wing of the panel which engage the (preferably bevelled) edge of the chevron-shaped aperture. The tabs are disposed in various quadrants around the centroid of each wing of the panel in order to create an integral fit of the long chevron wings to the cover and thus to reduce inadvertent detachment of the whole panel if a part of it is dislodged, or if the cover is deformed through heat or physical stress. Such positioning also provides multiple retention axes between tabs and creates lateral forces and bending moments, should any tab become dislodged, in order to continue securing the wing and the panel in place.
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