US Patent 8985364 Wall mounting apparatus and frame assembly

A self-supporting apparatus can be placed in an opening in an existing wall substrate. A frame assembly is configured with a perimeter that can be adjusted to correspond to the opening of the wall substrate. Opposing frame portions are movable in opposite directions with respect to each other to be expandable for contact with the opening. Each frame portion comprises a first side having a detent on one surface and a second side with at least one groove on a surface thereof. The surfaces of the opposing frame portions face each other. The detents and grooves are dimensioned to provide engagement, respectively, between grooves and dents of facing frame portion surfaces.