US Patent 12004660 Compliant backrest

A backrest includes a primary frame having a pair of laterally spaced first uprights defining a first opening therebetween, a first front surface and a first rear surface. A secondary frame includes a pair of laterally spaced second uprights defining a second opening therebetween, a second rear surface facing the first front surface of the primary frame and a second front surface, wherein the secondary frame is coupled to the primary frame, and wherein at least portions of the first and second openings are aligned. A flexible shell overlies and is coupled to the second front surface of the secondary frame. The flexible shell includes a third rear surface visible through the aligned portions of the first and second openings.