A counterbalance forklift works like a see-saw: the pivot point is the front axle. The load is in front and the counterweight behind. If the load «weighs» more than the counterweight, the truck tips forward.
The stability triangle
The truck is stable as long as the centre of gravity of the whole (truck + load) falls inside the stability triangle formed by the ends of the front axle and the centre of the rear axle. Things that push it out: turning fast, braking hard, driving with the load raised, going sideways on a slope or uneven ground.
The capacity plate
- Every forklift has a plate showing the maximum load it can take depending on the lift height and the load centre: the distance from the load's centre of gravity to the heel of the fork.
- The higher and further from the mast the load's centre is, the less weight it can take.
- Attachments (clamps, side shift…) add weight at the front and reduce capacity: check the plate for the truck with that attachment.
In practiceYour forklift takes 2,000 kg with the load centre at 500 mm. A long 1,800 kg pallet
with its centre at 700 mm may exceed its real capacity: check the table on the plate before you pick it up.