Forklift Types, Components, Stability and Load Charts
Forklift types and components
Forklifts come in many configurations: counterbalance (electric, diesel, LPG), reach trucks, order pickers, pallet jacks, and telehandlers. Key components include the mast, carriage, forks, overhead guard, backrest extension, counterweight, and data plate. The data plate (or load chart) specifies the rated capacity at a given load centre and lift height. Never exceed the rated capacity; capacity decreases as load centre increases or as load is raised.
Stability principles
The forklift operates on a stability triangle (or trapezoid) formed by the centre of gravity of the load and the truck. The centre of gravity must remain within this triangle. Factors affecting stability: load weight, load centre, lift height, mast tilt, acceleration/braking, turning speed, and ground conditions. A common rule: keep the load low (about 100–200 mm off the ground), travel with the mast tilted back, and avoid sharp turns.
Traps in exam questions
- Assuming capacity is constant; it reduces with load centre and height.
- Forgetting that attachments (e.g., clamps) reduce capacity.
- Thinking a heavier forklift is always more stable; stability depends on centre of gravity.
- Misreading the load chart: the load centre is measured from the face of the forks to the centre of the load.
Worked example
A forklift has a rated capacity of 2000 kg at 500 mm load centre. If the load centre is 600 mm, the capacity is reduced. Using the principle of moments, the allowable load is approximately (2000 × 500) / 600 ≈ 1667 kg. Always check the data plate for specific ratings.
Key points
- Never exceed the rated capacity on the data plate.
- Capacity decreases as load centre or lift height increases.
- Keep the load low and mast tilted back while travelling.
- Attachments can reduce capacity; check the data plate.
- Stability depends on keeping the centre of gravity within the stability triangle.