Pneumatic timer with eccentrically disposed valve needle

In a pneumatic timing device with improved adjustability, the combination comprising:

• a bellows;
• a body having a valve chamber and having a passageway of substantially circular cross section that extends along a longitudinal axis from the valve chamber into the interior of the bellows, the body forming a valve seat around the passageway;
• a valve needle with a longitudinal needle axis, with a shaft disposed for axial movement in the valve chamber and with a non-circular cross section portion formed around its shaft, positioned within the valve chamber, and cooperating with a non circular cross section portion of the body to restrict rotation of the needle, the valve needle also forming a valve stem of substantially circular cross section that extends along the needle axis into the passageway;
• biasing means, disposed within the valve chamber in relative sliding contact against at least one side of the valve needle portion that restricts rotation and extending the distance traveled by such restricting portion, for urging the valve stem into contact with a portion of the valve seat, and into a position where the needle axis is spaced off-center from the longitudinal axis of the passageway to form a crescent-shaped bleed area;
• and
• a rotatable adjustment means mounted on the body and coupled to the valve needle for axial movement of thevalve needle along the biasing means, the portion of the valve needle that restricts its rotation being in sliding contact with the biasing means to further restrict rotation and to limit tilt of the valve needle, thereby maintaining the shape and the orientation of the bleed area.