US PATENT SUBCLASS 417 / 402
.~.~.~.~.~ Constantly applied force in education stroke direction

Current as of: June, 1999
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417 /   HD   PUMPS

321  DF  MOTOR DRIVEN {32}
375  DF  .~ Fluid motor {9}
398  DF  .~.~ Rectilinearly reciprocating cylinder and piston-type motor {1}
399  DF  .~.~.~ Rectilinearly reciprocating cylinder and piston-type pump {2}
401  DF  .~.~.~.~ Integral pump and motor pistons {2}
402.~.~.~.~.~ Constantly applied force in education stroke direction

DEFINITION

Classification: 417/402

(under subclass 401) Apparatus in which there is provided means (e.g., spring) for continuously applying a force to the pump piston or part connected thereto for continuously urging the pump piston in a direction to contract the pumping chamber.

(1) Note. The means for applying the continuous force may be a double acting differential area fluid motor in which fluid pressure is constantly applied to one piston working face.

(2) Note. To be included under this definition the bias means must be other than a mere weight.