(under subclass 16) Apparatus provided with either a mechanical resilient means (e.g., spring) or a fluid pressure means other than that normally occurring within the working chamber in the operation of the device tending to move either the movable cylinder or portion thereof or the working member relative to one another to thereby vary the volumetric capacity of the working chamber.
(1) Note. The cylinder or outer member may be the working member or it may be in the form of a ring or a segment thereof.
SEE OR SEARCH CLASS
417, Pumps,
212+, and especially subclass 220 for rotary expansible chamber pumps in which the capacity is varied by a movable member (e.g., stator) the member being moved by the pump fluid and there being a condition responsive valve control of the pump fluid in its application or release to move the member.
