Patent ID: 8683694

Claim:
A method of forming a frame assembly comprising: (a) providing a plurality of frame members, each frame member defining an interior space divided into at least three longitudinal cavities, wherein the at least three longitudinal cavities comprise first and second inner longitudinal cavities and an outer longitudinal corner key cavity, wherein the first and second inner longitudinal cavities are located adjacent each other in a transverse direction relative to the longitudinal cavities, and wherein the outer corner key cavity at least partially overlaps both the first and second inner longitudinal cavities in the transverse direction; (b) providing at least one corner key, wherein each corner key has a first section and a second section, wherein each section of each corner key is configured to fit into one end of one of the outer corner key cavities; and (c) engaging the corner key with adjacent ones of the plurality of frame members; (d) wherein when the plurality of frame members are engaged together using one or more of the corner keys, the plurality of frame members define an outer boundary and an inner boundary, wherein the inner boundary defines an opening, wherein the outer corner key cavity is adjacent to the outer boundary and the first and second inner longitudinal cavities are located inwardly relative to the outer corner key cavity toward the inner boundary.