Basic Crane Limitations – Tool Box Talks

BASIC CRANE SET UP

  • A cranes capacity is different over the Sides than it is over the Front or Rear.
  • There is a difference in capacity if outriggers are extended. Fully Extend Outriggers (unless
    charts have ratings for other settings).
  • Pads 3 times the size of the floats.
  • Wheels Off the ground (just enough for clearance).
  • Barricade the entire swing radius and ensure NOBODY is within the swing radius while in use.

RADIUS

  • Increasing the radius generally reduces the total capacity

BOOM ANGLE

  • Is the angle of the boom to the horizontal.
  • Booming up reduces radius, increases boom angle, and generally increases capacity. Booming
    down increases radius, decreases boom angle, and generally decreases capacity.

TWO-BLOCKING

  • A condition when the ball or load block comes in contact with the sheaves at the tip.
  • This could cause the rope to break causing dynamic unloading which will drop the load and
    damage the crane.

DYNAMIC LOADING

  • Dynamic loading can dramatically effect the stability of the crane and is typically caused by rapidly
    accelerating or stopping a load.

SIDE LOADING

  • Typically cause by not having the tip of the crane over the load when trying to hoist or when there is a rapid
    start or stop of the swing.
  • This can cause sever structural damage to the boom and eventually cause failure of the crane boom.

EFFECTS OF WIND
From the Back

  • Effect of wind on the load increases the load radius and reduces capacity.
    Forward stability is the critical consideration when the wind is from behind the
    boom.
  • It has same effect as adding load to the hook.

From the Front

  • Effect of the wind on the load reacts at the boom tip by creating a backward tipping load.
  • Backward stability is the critical factor when the wind is from the front, particularly when the boom
    is at or approaching maximum boom angle.

From the Side

  • Boom Strength is most affected when the wind is from the side.

SAFETY REMINDERS – RIG IT RIGHT THE FIRST TIME-EVERYTIME!