Elbow

The name Elbow was used on the Japanese 6×6 TLR Elbow flex and 6×6 folder Elbow Six. It was marked ELBOW CAMERA FIRM. Japanese sites say that the company's name was Elbow Shōkai (エルボー商会); the word shōkai means "company" or "firm" but is generally used for wholesale or trade companies, so this sounds like a distributor's name.