What kind of device controls the tilt of the stacker mast?

The tilt of the stacker mast is controlled by a hydraulic system, which is responsible for the precise movement necessary for safely positioning loads. This system uses hydraulic fluid to transmit force, allowing for smooth and powerful adjustments in the mast's angle. The hydraulic control ensures that the stacker can maintain stability while tilting the mast, accommodating various load sizes and heights.

Electric motors typically provide power for driving the forklift or lifting functions but are not specifically responsible for mast tilt. Pneumatic actuators operate using air pressure, which is not standard in forklift systems where fluid dynamics effectively manage heavy loads. A rotary knob may control the hydraulic system but is not the mechanism that physically causes the mast to tilt; it merely serves as an interface for the operator to input commands to the hydraulic system. Thus, the hydraulic system is the correct answer as it directly performs the function of tilting the mast.