US PATENT SUBCLASS 417 / 490
.~ Pumping member position controlled port

Current as of: June, 1999
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417 /   HD   PUMPS

437  DF  EXPANSIBLE CHAMBER TYPE {40}
490.~ Pumping member position controlled port {8}
491  DF  .~.~> Common pumping member controls inlet or discharge for plural chambers {1}
493  DF  .~.~> Including plural controlled inlet or outlet flow paths {2}
496  DF  .~.~> Having serial control of inlet or discharge flow path
497  DF  .~.~> Pumping member controlled end wall port
498  DF  .~.~> Longitudinally spaced inlet and discharge sidewall ports
499  DF  .~.~> Having means to effect control at different positions of pumping member stroke
500  DF  .~.~> Control by movement of pumping member about axis
501  DF  .~.~> Having coextensive distributor opposite pumping member end face

DEFINITION

Classification: 417/490

(under subclass 437) Apparatus in which the supply or

discharge of pump fluid to or from the pump chamber is by way of a port which is controlled by opening or closing same upon movement (reciprocatory or rotary) of the pumping member relative to the pump chamber; said port being either (1) formed in a pump chamber wall (e.g., cylinder) and opened or closed directly by the pumping member (e.g., piston) or element integral with or movably carried thereby or, (2) formed in the pumping member and opened or closed directly by a pump chamber wall or element integral with or movably carried thereby.

(1) Note. For purposes of this definition, an element which is movably carried by the pumping member for controlling a chamber wall port may be movable relative to the pumping member but must move with the pumping member over at least a portion of the stroke thereof, the element itself serving to directly control a chamber wall port. However, a valve element which is mounted in a chamber wall portion and which is shifted by abutment or frictional engagement with pumping member is not considered to be movably carried by the pumping member and is excluded under this definition. See subclass 520.

SEE OR SEARCH THIS CLASS, SUBCLASS:

489, for a pump having an inlet or discharge path controlled by withdrawal or tilting of the pump piston relative to the cylinder therefor.

520, see (1) Note above.