The main components of the hydraulic cylinder are shown in the figure above.
While the lift arm (11) is rising, oil from the hydraulic pump flows into the hydraulic cylinder (4) through the position
control valve (14). Then oil pushes the hydraulic piston (7) out.
While the lift arm (11) is lowering, oil in the hydraulic cylinder (4) is discharged to the transmission case through
the position control valve (14) by the weight of the implement. At this time, the lowering speed of the implement can
be controlled by the lowering speed adjusting valve (3) attached to the hydraulic cylinder (4). Turning the lowering
speed adjusting knob (1) clockwise decreases the lowering speed, and counterclockwise increases lowering speed.
When the lowering speed adjusting valve (3) is completely closed, the lift arm (11) is held at its position since oil in
the hydraulic cylinder (4) is sealed between the hydraulic piston (7) and the position control valve (14).