In friction screw presses, two drive pulleys are located at the machine’s head, which can be axially shifted. The pulleys are driven by electric motors via flat belts. At the top end of the screw is the flywheel, which is fitted with a leather bandage on its circumference. The stroke is triggered using a lever or in the case of more modern machines by a foot- or hand-operated button. The drive pulleys are here axially shifted, and one of the two pulleys is pressed against the flywheel. The rotary movement transmitted by friction to the flywheel and the screw leads to a downward movement, as with a manual-spindle press. For the upward movement, the drive pulleys are shifted in the opposite direction, the second pulley pressed against the flywheel, whereupon the direction of rotation of the flywheel and the screw is reversed. In the case of relatively large machines, the two drive pulleys can be operated and shifted independently of each other. This serves, by exploiting the rebound impact and a slower-running drive pulley for the upward stroke, to minimise the wear and tear on the leather bandage.Search for specific products from 6233 suppliers