Patent ID: 7059350

Claim:
An airflow controlling mechanism comprising: a pneumatic cylinder having a cylindrical body with one end face, an air chamber being formed in the cylinder body, a forward and a backward vent respectively passing through the wall of one end of the cylindrical body for communicating the air chamber with outer side of the cylindrical body; an air valve having an annular body section with one end face and an outer cylindrical surface, said, one end face of the air valve abutting against one end face of the cylindrical body, two extension vents respectively extending through the body section in predetermined direction, the openings of two ends of each extension vent being respectively positioned one end face of the body section and an inner circumferences of the body section, the openings of the two extension vents positioned on the end face of the body section respectively communicating with the forward and backward vents; and an adjustment member having a disc-like base section with a certain thickness, the base section being coaxially accommodated in the body section, whereby the adjustment member can be turned between a clockwise position and a counterclockwise position, the circumference of the base section abutting against the inner circumference of the body section, an air passage radially extending through the base section, an opening of one end of the air passage being an outlet formed on the circumference of the base section in a predetermined position for communicating with the air passage and a corresponding extension vent.