Patent ID: 7270243
Filing Date: 2007-09-18
Classification: B66C

Abstract:
1. Method for erecting a lattice main boom of a lattice-boom crane subdivided into at least two lattice main boom portions, including a lower lattice main boom portion hinged to an upper carriage of the crane at a hinge point, and an upper lattice main boom portion, connected during assembly by a connection to the lower lattice main boom portion and connected during crane operation to the lower lattice main boom portion to form a unitary rigid lattice main boom, comprising: producing a starting position, in which the lattice main boom attached to the upper carriage of the crane is supported on at least one second point on the ground spaced apart from the upper carriage, the lattice main boom being assembled to a greatest in-use length; shortening the effective lever arm of the lattice main boom by producing an angle position between the lower and the upper lattice main boom portions to decrease a tilting moment producible by a lattice main boom weight; maintaining the second support point until the tilting moment producible by the lattice main boom weight is smaller than a standing moment of the crane; concurrently lifting both of the angled lower and upper lattice main boom portions by pivoting around the hinge point on the upper carriage of the crane; aligning to the greatest in-use length the lower and upper lattice main boom portions into a crane operating position; and after aligning the lower and upper lattice main boom portions, establishing a rigid connection between the lower and the upper lattice main boom portions.