14.8 Additional precautions when using mobile cranes
14.8.1 Precautions with lattice boom cranes
14.8.2 Precautions with hydraulic boom cranes
14.8.3 Precautions with pick-and-carry cranes
14.8.1 Precautions with lattice boom cranes
On lattice boom cranes, the top of the extended boom should not be lowered to a point below the horizontal line that passes through its base pivot pin. If the boom tips below this plane, the angle of pull of the boom luffing ropes could cause the boom to buckle before the boom begins to lift.
Lattice boom cranes should not be moved uphill with an unloaded boom in the near vertical position, or operated:
- with the boom at an angle less than that shown on the load chart; or
- with the boom hard against the boom backstop to avoid serious damage to the structural members of the boom. Regard the boom backstop as a safety device only.
14.8.2 Precautions with hydraulic boom cranes
When extending the boom on hydraulically operated cranes, ensure that the boom sections are extended or retracted in accordance with the manufacturer’s recommendations. Boom sections have failed through being extended contrary to recommendations.
The crane should not be operated with the boom at an angle less than that shown in the load chart.
14.8.3 Precautions with pick-and-carry cranes
When moving a load in the pick-and-carry mode, the dogger should remain in sight of the crane operator, and not walk in the path of the crane. When travelling and manoeuvring with a load, the crane operator should ensure that:
- the slew brake is applied at all times other than when the slew motion is being used;
- precautions are taken on uneven road surfaces when loaded or unloaded, as an undulation in the road surface may move the crane into an unstable zone;
- the slewing brake or lock is applied when travelling with a load; and
- the crane is not moved uphill with an unloaded boom in the near vertical position.
Always travel slowly to prevent excessive swinging of the load. The load should be carried as close to the ground as possible, and should not lift higher until it is almost in position.
Where possible, avoid travelling the mobile crane across slopes or over potholes, depressions, soft ground, road chambers or shoulders, rail tracks, dunnage wood or any objects, as these could destabilise the crane or load.
Last updated June 9, 2006