Patent ID: 8985353
Filing Date: 2015-03-24
Classification: B66C

Abstract:
1. A mobile lift crane comprising: a) a carbody having moveable ground engaging members; b) a rotating bed rotatably connected about an axis of rotation to the carbody such that the rotating bed can swing with respect to the ground engaging members; c) a boom pivotally mounted on a front portion of the rotating bed; d) a mast mounted at its first end on the rotating bed; e) a moveable counterweight unit; and f) a counterweight movement structure connected between the rotating bed and the counterweight unit such that the counterweight unit may be moved to and held at both a forward position and a rearward position; g) wherein the crane has a total amount of counterweight of at least 250 metric tonne and a maximum rated load moment of at least 6,250 tonne-meters, and the ratio of maximum rated load moment to total weight of the counterweight is at least 25 tonne-meters/tonne.