Technology

Learn more about the E-Crane technology

Why Balanced Design is Better for Your Business

Balance is one of the key factors for any crane in the industry. Without the right balance, a crane will lose its stability. To avoid this, all cranes know the principle of the ‘counterweight’. In most cases this counterweight is at a fixed point on the crane, but on an E-Crane, the counterweight is linked to the stick, so it can automatically compensate for the lifted load.

Only E-Crane Finds True Balance

The balance crane provides a fail-safe system which guarantees that the crane will always be in balance. The link between the stick and counterweight creates a 4-bar mechanism, which ensures that the counterweight continuously balances the total weight of the steel structure along with half of the operational load. As the lifting radius is varied, the change in the load moment is automatically equalized by the moving counterweight.

The Physics

The balance or equilibrium of a crane can be described as: F1 x d1 = F2 x d2

F1 The load applied at the end of the stick
d1 The distance from the load to the pivot point
F2 The load of the counterweight
d2 The distance from the counterweight to the pivot point

Energy Savings Thanks to Balanced Design

Lower energy consumption means lower costs! With traditional hoisting machinery, the payload, working tool, and steel construction have to be raised, but the E-Crane’s balance compensates for all but the payload. It goes without saying that this results in important energy savings.

The Problem with Conventional Cranes

To be balanced at any given position, the counterweight has to continuously compensate for the load. As the load increases, the counterweight must also increase in weight. Alternatively, instead of increasing the counterweight, it could be moved further rearward from the center of rotation to compensate for the increase in the load.

For example, a one ton load at a twenty foot radius gives a forward load moment of twenty. This load moment would then be equalized or counterbalanced by a 4 ton counterweight at a distance of five feet, having rearward load moment of twenty (20 x 1 = 4 x 5).

Since adding counterweight is often neither practical nor, in some cases, recommended, true balance of a fixed counterweight crane can only be achieved at one specific radius. Any variation caused by changing the radius at which the load is lifted, destroys the balance.

Selected Case Studies