US PATENT SUBCLASS 137 / 535
.~.~.~ Spring biased

Current as of: June, 1999
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137 /   HD   FLUID HANDLING

455  DF  LINE CONDITION CHANGE RESPONSIVE VALVES {11}
511  DF  .~ Direct response valves (i.e., check valve type) {14}
528  DF  .~.~ Reciprocating valves {5}
535.~.~.~ Spring biased {5}
536  DF  .~.~.~.~> With means to protect spring from fluid
537  DF  .~.~.~.~> Spring under tension
538  DF  .~.~.~.~> Piston-type valves
539  DF  .~.~.~.~> Ball valves {1}
540  DF  .~.~.~.~> Spring coaxial with valve {9}

DEFINITION

Classification: 137/535

(under subclass 528) Valves in which the elasticity of a resilient element is used to provide the biasing force.

SEE OR SEARCH THIS CLASS, SUBCLASS:

525, for resilient material valves of the direct response type and see the search notes thereto.

SEE OR SEARCH CLASS

251, Valves and Valve Actuation,

336+, for spring biased valves of this class, and see the search notes thereto.