Forklift glossary

As in almost all industries, forklifts are associated with numerous terms that may not be familiar to all at first glance. The spec list of forklift trucks may include some unfamiliar terminology that may actually play a role in succesful selection of the forklift. Below is a list of terms that we get asked about on a weekly basis. If there is something you need more information on, please let us know. We will add to this article to help others too.

Fork sideshifter / spread

The fork positioner / spread is an attachment that allows for hydraulic movement of the forks in two ways. The forks can be moved from left to right and they can be spread or moved closer to each other. This attachment speeds up working with different pallet sizes and is a common feature in most of the forklift trucks in our stock. It is also possible to equip the truck with just a side shifter which means you would have to alter the width of the forks manually. There are many types of fork attachments available, both with integrated and interchangeable forks.

Please note that the installation of a fork attachment may affect the actual lif capacity and the load center of the forklift.

Load center distance

Each forklift has a load center distance that is specified by the manufacturer. The distance indicates the distance from the base of the forks to the center of the load. For counterbalance forklift trucks, the usual load center distances are 500 or 600 mm. Why is this information important? Contrary to popular belief the rated maximum lift capacity of the forklift does not mean that the forklift can lift that exact load to full height regardless of the dimensions of the load. For example, the manufacturing plate below is from a counterbalance truck with a rated lifting capacity of 4000 kg. As you can see from the chart, a 100 mm change in the load center affects the actual lift capacity at maximum height by 300 kg.

It would be possible to write an entire post covering the load center, but what matters is that you take into account the constraints of the truck before purchasing one, and especially before using it. The load center distance determines the size and weight of the load that the forklift truck can safely lift.

Masts: Simplex, duplex, triplex...

Most forklifts, be it counterbalance trucks, reach trucks or pallet stackers, are available with different masts. As you would guess, the mast type affects the maximum lift height of the forklift. But the different mast types have a couple of other characteristics too. Tip: When choosing a suitable mast and lift height, leave about 10-15 cm of wiggle room between the maximum lift height requirement (e.g. the top shelf of the warehouse) and the maximum lift height of the forklift. This allows loads to be moved more easily even at greater heights.

1. Simplex (one-stage mast) The Simplex mast has only one channel, so its lifting height is limited and doesn't have a free lift feature (more on free lift later). Simplex masts are best suited for outdoor work or working environments where the driving height of the forklift is less crucial.
2. Duplex (two-stage mast) The outer structure of the two-stage mast remains in place and the inside beams of the mast rise. The Duplex mast enables good visibility and can accommodate the free lift function.
3. Triplex (three-stage mast) The Triplex mast is by far the most common mast type you see in our forklift stock. As with the duplex mast, the mast's outer structure remains in place and two inner extensions rise. Three-stage masts almost always have a free lift feature. Triplex masts are suitable for most warehouses.
4. Quad (four-stage mast) Four-stage masts are less common, but they can be found in both counterbalance trucks and reach trucks. The advantage of the four-stage mast is a large maximum lift height and a low driving height of the forklift truck.

Free lift

When looking at forklift specs, free lift is usually expressed in millimetres. The figure indicates how high you can lift the load before the mast's extension begins to rise. Free lift is a useful feature when you need to lift and handle loads in areas with limited height, say in a container for example. Without free lift, the mast begins to extend right away, therefore altering the driving height of the truck.

Initial lift

Some pallet stackers are equipped with an initial lift function. Initial lift is used to increase the ground clearance of a forklift making it easier to cross thresholds, for example.

Did the article raise any questions?

If you wish to know more about the topics in this article or anything else forklift-related, please let us know. You can always call, send a message or fill out the contact form at the bottom of the page.