In the case of a two-axis automatic or process crane, besides the lifting movement the carriage too is mobile.
The movement speed of the carriage on the crane gantry averages 2,5 m/s, depending on the width of the gantry. The lifting speed is of the order of 1 m/s.
For the movement of the carriage CFC-controlled asynchronous synchro-geared motors are used. Synchronisation of the carriage chassis is ensured by a rack-bar drive system. Path measurement is by means of absolute-value emitters. Furthermore, additional device (contour checking instruments, bar-code reader units and others) can be fixed on the carriage.
The lifting gear, with an 8/4-strand cable drive, is equipped with an overload and slackness device for each strand. Moreover, on the lifting equipment is integrated a lifting speed control for the end position of the gripper.