when was the sleeper sofa invented

[DeJuliette]

Based on the provided information and general knowledge, the modern sleeper sofa is credited to Bernard Castro. He was the American inventor of the patented "Castro convertible" sofa bed.

While the provided context does not specify the exact year of the invention, Bernard Castro founded his company, Castro Convertibles, in 1931. It was during this time that he designed and began manufacturing his innovative piece of furniture. His design was significant because it was the first to fully conceal the bed mechanism within a stylish sofa, creating a truly dual-purpose item that did not compromise on aesthetics. The ease of converting it from a sofa to a bed was also a key feature that led to its widespread popularity. The provided sources correctly identify him as the key inventor and note his death on August 24, 1991.