Ventilator e.g. hydraulic ventilator, for use in rotary part of engine, has piston back hollow drive i.e. spring, provided on back hollow side of piston for changing blade upward gradient of ventilator blades

摘要

The ventilator (10) has a circumference hub (12) with a front side and a back side. A mounting plate (24) is provided at the back side of the hub. Ventilator blades (14) extend radially outward from the hub. A front plate (30) is provided at the front side of the hub. A piston (40) is connected with the blades to control blade upward gradient. A rotating unit (26) provides hydraulic supply to a drive side (52) of the piston, and a piston back hollow drive (60) i.e. spring, is provided on back hollow side of the piston for changing the blade upward gradient.