With the certain boom and hoist tackle combinations, maximum capacities may not be obtainable with standard cable lengths.Tires shall be inflated to the recommended pressure before lifting on rubber.When equipped with an extendable counterweight, the counterweight shall be fully extended before operation.

If the machine is equipped with a front jack cylinder, the front jack cylinder shall be set in accordance with written procedure.For outrigger operation, outriggers shall be properly extended with tires raised free of crane weight before operating the boom or lifting loads.Depending on the nature of the supporting surface, it may be necessary to have structural supports under the outrigger floats or tires to spread the load to a larger bearing surface. The machine shall be leveled on a firm supporting surface.2 Lifting operations risk assessment example.With our example of 2 tonne at 3 metres, if the load or sling length causes the hook to be so high that the inner boom cannot be used for the lift, then probably an 8 tonne metre crane would be the size required.Ī winch rope crane will give a vertical lift as seen in Figure 2 (therefore no increase in radius), so this consideration is not applicable to UNIC & Cobra telescopic boom cranes fitted with winches. The resulting increase in the radius can be substantial and is often sufficient to over pressurize the luff rams and to activate the overload protection (if fitted) which may prevent the crane moving into the required position. The operator may not get sufficient hook height to clear the base of the load over the tray body. In this configuration, only the outer boom can be raised. To handle a high load of near crane capacity, the inner boom must be vertical (or near to vertical), and the outer boom pointing down, with the hook above the centre of the load. You would need a crane rated at 6 tonne metres or better to do the job BUT it is important to consider the physical size of the load you are lifting. But with high or long slung loads, this calculation can lead to an embarrassment! If we say that we need to lift 2 tonne at 3 metres, we would look for a 6 tonne metre crane. Caution: Heavy (in close) lifts have a complication.

Mobile crane lifting capacity