Multiple throttle level orifice apparatus

Abstract

An orifice apparatus is provided which couples a vacuum advancer of a distributor associated with an engine for a vehicle with a carburetor of the engine. The orifice apparatus includes a body having an upper and a lower opening between which an isolation wall is formed in which a plurality of orifices are circumferentially spaced apart at an equal angular interval. A plurality of orifice members are disposed below the isolation wall and each has an orifice of a different diameter formed therein which is located below one of the plurality of orifices. A rotary plate is disposed above the isolation wall and is secured to a regulating member in the form of a rotatable shaft. A seal member is bonded to the lower surface of the rotary plate, which is formed with a passage port which can be brought into alignment with one of the plurality of orifices formed in the isolation wall. The rotary plate is urged by a single coiled spring toward the isolation wall so that the seal member is pressed to provide a hermetic seal between the rotary plate and the upper surface of the isolation wall. The seal member is formed with a plurality of openings, each corresponding to one of the plurality of orifices in the isolation wall and having a greater dimension than the corresponding orifice. These openings are circumferentially spaced apart at an equal angular interval. The regulating member is driven for rotation to move the passage port of the rotary plate from a position in which it is substantially aligned with one of the plurality of orifices formed in the isolation wall to another position in which it is aligned with another orifice, whereby the particular orifice which provides a communication between chambers formed in the body of orifice apparatus above and below the isolation wall is changed, thus changing the throttle level of the fluid path which joins the chambers.