Two identical pulleys 2 and 3 rotate about fixed axes A-A and B-B which cross at right angles. Quarter-turn belt 4 runs over pulleys 2 and 3, contacting the pulleys with one side. Idler pulley 1, rotating about fixed axis C-C, both tensions and guides the belt. The transmission ratio from pulley 2 to pulley 3 is i₂₃=1, i.e. the pulleys rotate at equal speeds and, looking along axes A-A and B-B in the directions of the arrows, they both rotate clockwise.
$3513$SFL,BD$