US PATENT SUBCLASS 428 / 580
.~.~.~ Symmetrical

Current as of: June, 1999
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428 /   HD   STOCK MATERIAL OR MISCELLANEOUS ARTICLES

544  DF  ALL METAL OR WITH ADJACENT METALS {31}
577  DF  .~ Intermediate article (e.g., blank, etc.) {3}
578  DF  .~.~ Panel having nonrectangular perimeter {2}
580.~.~.~ Symmetrical {1}
581  DF  .~.~.~.~> Only one plane of symmetry

DEFINITION

Classification: 428/580

(under subclass 578) Subject matter having a plane of symmetry and a correspondence in size, shape and relative position of parts such that if a plane mirror is placed in the plane of symmetry, parallel to a thickness surface or perpendicular to a nonthickness* surface of the article, half the object, plus the mirror image of this half, appears the same as the entire object.

SEE OR SEARCH CLASS

277, Seal for a Joint or Juncture,

325, for a radially actuated segmented seal (e.g., ram type, etc.) for a well overpressure control device (e.g., seal for a blowout preventer, etc.), subclass 344 for a segmented

radially actuated packer (e.g., oil saver, gas saver, etc.) for above ground apparatus of a well, subclass 493 for a segmented piston ring, subclass 533 for a dynamic segmented seal having a wedging surface contained or compressed by gland member in a packing box, or subclasses 543+ for a dynamic segmented circumferential contact seal for other than a piston.