3. Mast elevators

A forklift mast very rarely consists of a single fork carriage guide frame. More often than not, there are two: one fixed and one mobile, guided by the first. However, the high lift heights of modern forklifts mean that, to reduce the overall height of the machine in the lowered position, the mast is composed of three or even four frames. These are known as double, triple or quadruple telescopic masts.

In a telescopic mast, the lifting cylinder(s) raise(s) the mobile frame and, simultaneously, a set of chains mounted on pulleys fixed to the mobile frame raises the fork carrier in the mobile frame. The mobile upright(s) are thus raised at the same time as the fork. However, in order to avoid increasing the overall height of the truck as soon as it is loaded, the elevator system features a so-called "free lift" system. This is an initial lifting phase during which...