Forklift Mast Types
Among the most important factors to consider prior to purchasing a forklift is the mast. Also known as the upright, a forklift’s mast is traditionally located on the front of the unit and facilitates the vertical movement and sideways positioning of loads. A number of mast variations exist, which, depending on your application, have their own advantages and disadvantages. What mast you select ultimately depends on your application, what you need to lift and how high it needs to go.
The most common forklift mast types include the following:
Single Stage – also known as a simplex mast, single stage masts are composed of a stationary outer channel and sliding inner channel, with a fork and carriage, that’s attached to lift chains to facilitate vertical movement. In this setup, the forks are elevated in lockstep with the inner channel. Under this configuration, the height of the outer channel represents the maximum lift height for this mast type. Obviously, this presents some significant limitations in terms of lift height and requires a higher lowered height than other variations. As such, the single stage or simplex mast is most often seen in outdoor applications where overhead clearances are not a concern.
Two Stage – also known as a duplex mast, two stage masts are similar in composition to a single stage mast in that they are composed of an inner and outer channel. However, the main difference here is that full free lift is available with duplex masts, allowing the forks to raise without extending the mast above the height of the outer channel. Given their construction and limited lift height (generally 157.7”), two stage masts allow a forklift to lift its full rated capacity up to its maximum lift height without further down rating. In terms of applications, these masts are most frequently found in cross-docking, manufacturing and inside trailers / box cars due to their improved visibility versus a three stage mast.
Three Stage – also known as a triplex mast, three stage masts are by far the most popular mast configuration, in large part due to their versatility and widespread availability. Here, an additional inner channel is added to the two channel setup of the previous two mast types (thus the three stage or triple mast designation). However, a key difference on three stage masts is that a central hydraulic ram is mostly responsible for lifting the forks and carriage, with additional side-mounted hydraulics to raise the middle section and lift chains. While this setup provides reduced forward visibility, it also allows for greater lift heights and full free lift, making it a great option for a variety of applications including warehousing and logistics.
Four Stage – widely referred to as a quad mast, four stage masts are highly specialized masts intended to reach extra high lift heights upwards of 275.6”. The lift heights achieved with four stage masts are accomplishing by utilizing three inner channels and an outer channel. And, while this allows the mast to extend to greater heights, it also dramatically down rates the forklift, considerably lowering its maximum lift capacity. As a result, these masts are only used in highly specialized warehousing applications.
With all of that said, what should you take into consideration when selecting a forklift mast type? Are there certain factors that should play heavily into your decision? Among the things to keep in mind include the following:
Lowered Height – each mast will have a different lowered height (i.e., the height of the mast structure when it is completely lowered to the ground) depending on the type of mast and its maximum lift height. Obviously, if your facility has specific height restrictions for entrances/exits, docks, and/or overhead clearances, you’ll want to take this into consideration when selecting a mast type. This is particularly important if you’re stacking loads inside of trailers or box cars, as you’ll need full free lift and a lowered height under the maximum clearance within the trailer/container.
Lift Height – obviously, you’ll need to select a forklift mast type that’s capable of reaching your highest shelving. However, you also need to keep “lift off” in mind when determining the lift height you require. Here, you’ll need to add at least 6 inches to the height of your racking to make sure the pallet or load can safely clear racking.
Free Lift – as previously mentioned, not every forklift mast the feature known as free lift. Here, an additional lift cylinder, located in the middle of the mast, allows the forks to raise without increasing the lowered height of the mast. This is essential in applications where loads are double stacked in trailers and box cars as this allows you to maintain the overhead clearance while stacking one load on top of another. At the same time, you should also keep in mind that the addition of full free lift decreases forward visibility down through the mast, so, if it’s not needed and visibility is important, consider other options.
Fortunately, Stärke forklifts and lift equipment are available in a variety of different mast types and lift heights. So, if you need help deciding what mast type best suits your needs, visit our dealers page to find a Stärke dealership near you or contact us today for more help.