Crane with movable counter weight has limit switches registering when jib unit tilts forwards or back and sending signal to electronic switch to cause counter weight to adapt automatically

摘要

The jib unit which has a front (2) and rear boom (3) is connected to the crane turret by an axis (9) so that it can tilt about same. Limit switches (10) are attached to register when the jib unit tilts forwards or back and then send a signal to an electronic switch (12) which by controlling the motor (7) causes the counter weight (5) to move to adapt the counterweight moment to the load moment. The tilting of the jib unit is damped by springs (10).