A pulley on a spring-mounted arm adjusted for the chain slack; this system was originally introduced in the 1884 patent of Linley, Biggs and Tandy.
） A pulley on a spring-mounted arm adjusted for the chain slack; this system was originally introduced in the 1884 patent of Linley, Biggs and Tandy. （→スプリング付きアームにてチェーンの弛みを調整した。