Wood parts, not out of place, at all. Just took someone to think to design it for this purpose. The mechanism is akin to a recliner's hardware. There are many variations of this hinged technique and technology being used.
Leggett and Pratt, for one, are pioneers in making these types of mechanisms. I think its their Omega division that specializes in designing & making many of these types of specific hardware.
Proteas furniture is another that designs/makes the hardware. I think you can order the mechanism, then modify/transform your couch, yourself.
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