TLILIC0003 Forklift Stability and the Stability Triangle 1 — Questions and Answers
Question 1: What is the 'stability triangle' on a standard counterbalanced forklift?
- The three-point suspension formed by the two front wheels and the rear axle pivot point (Correct answer)
- The triangular shape formed by the mast, forks, and counterweight
- The area between the load, the operator, and the rear axle
- The three contact points between the forks and the load
Correct answer: The three-point suspension formed by the two front wheels and the rear axle pivot point
The stability triangle is the three-point support system created by the two front drive wheels and the single pivot point of the rear steering axle, defining the area within which the forklift's combined centre of gravity must remain.
Question 2: On a counterbalanced forklift, where is the fulcrum point located?
- At the centre of the rear axle
- At the tips of the forks
- At the front axle between the two drive wheels (Correct answer)
- At the base of the mast
Correct answer: At the front axle between the two drive wheels
The fulcrum point is at the front axle (between the two drive wheels), and it is the pivot point over which the forklift can tip forward if the combined centre of gravity moves in front of it.
Question 3: What happens if the combined centre of gravity moves outside the stability triangle?
- The forklift's speed automatically reduces
- The forklift will tip over in the direction the centre of gravity has moved (Correct answer)
- The load capacity indicator will sound an alarm
- The rear wheels will lift, but the forklift remains balanced
Correct answer: The forklift will tip over in the direction the centre of gravity has moved
If the combined centre of gravity moves outside the stability triangle, the forklift will tip over in that direction because there is no longer a support point to counteract the overturning force.
Question 4: What is the 'combined centre of gravity' on a forklift?
- The centre of gravity of the load alone
- The centre of gravity of the empty forklift alone
- The single point representing the combined weight distribution of both the forklift and its load (Correct answer)
- The midpoint between the front and rear axles
Correct answer: The single point representing the combined weight distribution of both the forklift and its load
The combined centre of gravity is the single resultant point that represents the combined weight distribution of the forklift and the load it is carrying, and it must remain within the stability triangle for safe operation.
Question 5: Which type of stability refers to the risk of a forklift tipping sideways?
- Longitudinal stability
- Lateral stability (Correct answer)
- Rotational stability
- Dynamic stability
Correct answer: Lateral stability
Lateral stability refers to the resistance to sideways tipping, which is primarily affected by the width of the rear axle, cornering speed, uneven surfaces, and off-centre loading.
Question 6: Which factor directly reduces a forklift's longitudinal (forward/backward) stability?
- Using pneumatic tyres instead of solid tyres
- Carrying a heavy load with the mast tilted fully back
- Raising the load to a greater height while stationary (Correct answer)
- Operating at low speed on a flat surface
Correct answer: Raising the load to a greater height while stationary
Raising the load to a greater height shifts the combined centre of gravity upward and forward, moving it closer to or beyond the fulcrum point and reducing longitudinal stability.
Question 7: What is the primary purpose of the counterweight on a counterbalanced forklift?
- To increase the speed of the forklift when travelling without a load
- To offset the weight of the load being carried and keep the combined centre of gravity within the stability triangle (Correct answer)
- To provide additional braking force when descending ramps
- To protect the engine from damage during collisions
Correct answer: To offset the weight of the load being carried and keep the combined centre of gravity within the stability triangle
The counterweight is positioned at the rear of the forklift to offset the weight of the load on the forks, preventing the forklift from tipping forward and keeping the combined centre of gravity within the stability triangle.
TLILIC0003 Forklift Stability and the Stability Triangle 1
What is the 'stability triangle' on a standard counterbalanced forklift?