Reach trucks are specialized forklifts designed to move pallets in narrow warehouse aisles and lift them to high storage positions. They matter because they increase storage density by allowing taller racks and narrower travel lanes than many counterbalance forklifts require. A reach truck uses an extending mast or pantograph mechanism so the forks can reach into a rack while the truck body stays in the aisle.
Understanding their motion, stability, and safe operating limits helps warehouse teams move goods faster while reducing damage and injury risk.
The key idea is balance: the truck, load, battery, mast, and wheels create forces and moments that must stay within safe limits. As the mast extends or rises, the load center shifts, which can reduce stability and change the maximum safe load. Operators use load charts, aisle measurements, speed control, and visual alignment to keep the pallet, forks, and rack position under control.
In a warehouse system, reach trucks work with rack design, floor quality, traffic rules, and inventory software to create an efficient material flow.
Key Facts
- Load moment = load weight x horizontal distance from the front axle
- Safe capacity decreases as lift height, reach distance, or load center increases
- Typical reach truck aisle widths are about 2.4 m to 3.0 m, depending on truck and pallet size
- Stability improves when the load is carried low during travel, usually about 10 cm to 15 cm above the floor
- Stopping distance increases with speed, floor condition, load mass, and operator reaction time
- Mechanical power for lifting can be estimated by P = mgh / t
Vocabulary
- Reach truck
- A narrow-aisle lift truck with forks or a mast that extends forward to place or retrieve pallets from racks.
- Load center
- The horizontal distance from the fork face to the center of gravity of the load.
- Mast
- The vertical lifting structure that raises and lowers the forks and load.
- Rated capacity
- The maximum load a truck can safely lift under specified height and load center conditions.
- Center of gravity
- The point where the weight of an object or combined system can be treated as acting.
Common Mistakes to Avoid
- Using the rated capacity as a universal limit is wrong because capacity changes with lift height, load center, and mast extension.
- Traveling with the load raised is wrong because it raises the combined center of gravity and increases the risk of tipping or striking racks.
- Ignoring pallet dimensions is wrong because a longer or uneven pallet can move the load center forward and increase the load moment.
- Turning sharply in a narrow aisle is wrong because side forces and limited clearance can cause instability, rack contact, or product damage.
Practice Questions
- 1 A reach truck lifts a 900 kg pallet from the floor to a rack position 7.0 m high in 20 s. Estimate the useful lifting power using P = mgh / t with g = 9.8 m/s^2.
- 2 A 700 kg load has its center of gravity 0.60 m from the fork face. What is the load moment in kg m? If the load center shifts to 0.80 m, what is the new load moment?
- 3 A warehouse wants to store pallets higher to save floor space. Explain why the operator may need to reduce load weight as lift height increases, even if the truck can lift the pallet at a lower height.