The AG 2591 is a linear actuator from Erhardt+Leimer for positioning roll stands in printing machines. It consists of a shunt-wound D.C. planetary geared motor with ball screw, characterized by high efficiency and precise positioning movements. The follow-up speed is very accurately defined through the feedback provided by the integrated encoder to the control- ler. When the drive reaches its limit posi- tion (max. motor current) it is cut out by the digital web guider. Actuator AG 2591 incorporates mecha- nical stops. A gaiter protec ts the screw totally against the ingre ss of dirt. In addition to its application on reel stands, actuator AG 2591 is also used to position roller assemblies, for example on pivoting frames.