They operate with 3 (three) guiding parts on an aluminum trunk and a special arm movable at both directions driven from the center.

The spring mounted on a three way joint is controlled with centrifugal force by a control arm and a polyamide rod extending down and connected to it.

Pulleys are guided right or left by moving the arm right or left at the direction the hook comes.

Springs moved at the desired direction when using, send all the hooks to the same direction without any need for a second intervention.