Patent ID: 7201360

Claim:
A pneumatic device having a selectively variable pneumatic output and comprising: an air chamber having an inlet adapted for connection to a source of pressurized air and an outlet, the inlet and the outlet in flow communication along a flow path; an orifice plate disposed in the flow path between the inlet and the outlet, the orifice plate including a first primary orifice having a first size and a second primary orifice having a second size; a selector plate disposed adjacent to the orifice plate and having only a single control orifice and only a single mounting aperture, the selector plate and the orifice plate moveable relative to each other between a first position in which the control orifice is aligned with the first primary orifice to permit flow through the first primary orifice and the control orifice while blocking flow through the second primary orifice, and a second position in which the control orifice is aligned with the second primary orifice to permit flow through the second primary orifice and the control orifice while blocking flow through the first primary orifice; and wherein the orifice plate and the selector plat comprise concentric discs.