履带起重机操作手册

Operator’s Manual for Crawler Crane

Operator’s Manual for Crawler Crane

Caution

(1) Never stand directly underneath a lifted load. Observe the instruction “No person is allowed to stand under the boom when the crane is operated”

(2) Tail the load by tagline with proper force. Otherwise the crane may topple over.

(3) Never wrap the tagline around your body or limbs

3.3.7 Load center of gravity

a) The center of gravity b) To determine the center of gravity

The center of gravity of an object is the point at which the weight of the object acts as though it were concentrated.

All loads to be lifted must be equipped with lifting device and rigging above the center of gravity in order to prevent tipping and possible hazards to equipment and workers. The lifting force must always be located above the center of gravity Exert a straight vertical pull to prevent swinging of the load. In all crane lifts, the center of gravity must remain below the hook and below the point of attachment for any rigging.

A center of gravity above the hook is unstable and will cause the load to flip as the load will attempt to ‘find’ the center of gravity during lifting process. Similarly, loads which are not balanced horizontally can slip from the rigging. The overall stability of the load is a combination of balance with respect to center of gravity, distribution of weight, and proper rigging practices.

The center of gravity of a regularly shaped object may be estimated accurately by determining its approximate center.

Finding the center of gravity of irregularly-shaped objects can be more difficult, but it is necessary. A load will always hang from its attachment point through the center of gravity. It is important to visualize this before making a lift.

3.4 Requirements for operating site

Operator’s Manual for Crawler Crane