Types of Forklift Masts
Forklifts are a vital piece of equipment for most warehouses. They allow workers to move products and materials in a timely manner. They also increase warehouse storage space in two ways. The ability to lift heavy loads allows products to be stacked high. Forklifts can also be safely navigated in narrow aisles and tight corners. Best of all, forklifts are durable machines that can withstand heavy workloads day in and day out.
One of the most important parts of a forklift is its mast. Also called the “upright,” the mast performs the task of lifting and lowering the load on the forks. There are many forklift mast types, each with its own height and stacking limits. Knowing the features of the different forklift mast types will help you get the right forklift for the job.
Different Types of Forklift Masts
Most forklift masts are of the straight type. They consist of an upright vertical assembly on the front of the truck which is used to raise and lower loads. All straight mast forklifts use hydraulic displacement for lifting, and gravity to lower the loads.
There are four different types of straight mast forklifts. Each type offers different features and capabilities.
Single Stage Upright.
This type of forklift mast is sometimes called a “standard upright” or “V-mast.” It consists of a two-stage assembly with two rails. One assembly moves up and down. The other one doesn’t. Two cylinders mounted on the side provide lift to the rails. An indirect chain provides lift to the carriage/fork assembly.
Single stage forklift masts have one channel, which has a limited lifting height (a.k.a “maximum fork height”). These forklifts don’t provide full free lift, which is the ability to lift the load without moving the mast channel. As a result, the mast must extend higher than other masts when stacking loads. Full free lift is useful when working with tight overhead height restrictions. However, it can interfere with the driver’s line of sight during the lifting.
Single stage masts work best with:
- Low lift heights
- Self-propelled, walk-behind equipment
- Outdoor jobs where overhead clearance isn’t a problem
Two Stage Mast
This type of forklift is also known as the “Duplex Upright.” The mast has a two-stage assembly with a center-mounted cylinder can provide the full free lift. The cylinder raises the carriage to the top of the inner rails at a 2-to-1 ratio. At that point, hydraulic fluid gets rerouted to the secondary cylinders to provide the direct rail lift. Unlike stage one mast, the two stages provides full free lift.
Two-stage forklifts are great for handling heavy loads at low lift heights. The two stage masts are common in high-capacity forklifts of 15,000 pounds or more. Two-stage masts are best used for:
- Stacking and double stacking
- Indoor jobs where overhead clearance is limited
- Trailers and box cars where visibility can be poor
Three Stage Mast
The three-stage, or triplex mast forklift, is one of the most commonly used masts. It makes for a very versatile forklift. The higher lift capabilities of the three-stage make it well suited for many warehouse jobs. Three stage mast forklifts with base a capacity of 2,000 to 6,000 lbs. can lift up to almost 16 feet.
The three-stage uses three rails to provide a three-stage lift with full free lift. Two of the rails are movable. One is stationary. The main cylinder provides the full free lift of the carriage and forks. The secondary lift cylinders lift the intermediate rails. For the final lift, the chains pull the inner set of rails along with the carriage/fork assembly
The three-stage mast is ideal for jobs where:
- The forklift needs to reach above-average heights
- Full free lift is required
- Duplex masts are not available
Four Stage Mast
The four-stage mast forklift uses four sets of rails and a second set of chains to provide the highest reach among forklifts. It is also called a “Quad” mast, and works much the same way as three stage masts. The main difference is the extra set of chains and pulleys that provide the fourth stage of lift. Quad masts also offer full free lift, but the lifting capacity declines with heavier loads.
Ideal for high stacking in specialized warehousing, quad masts:
- Can load and unload higher-tiered stacks than double or triple stage masts
- Can lift to heights up to 20 feet
- Require extra caution due to their high lifting ability
Forklift Mast Functionality and Safety
When buying a forklift, keep these factors in mind:
- Lift height. When choosing the mast, add at least six inches to the height of your tallest racking shelf. This will provide enough clearance for drivers to safely handle loads at height.
- Height when lowered. Each forklift mast type comes to rest at a different height when fully lowered. Make sure the model you choose can fit any height restrictions for your doorways, loading docks and other points of entry.
- Some forklift mast features can reduce the lifting capacity of the truck. Examples include the side shift on a triple stage mast or an extended tilt. Suppose your forklift has a base capacity of 5,000 lbs. Raising it up to 188” and tilting all the way forward could cut your base capacity in half.
- Load backrest. Many warehouses have lights, sprinklers, or other items that could be damaged by lifting. If your forklift has a 48-inch load backrest, you may want a different size. Ask the manufacturer to customize the backrest to your needs.
Forklift Mast Safety Training
When using a forklift, worker safety is always the top priority. No matter what forklift mast type you use, every driver should be fully trained and certified before getting behind the wheel. For fast, affordable forklift operator training, visit us at forkliftcertification.com.