US PATENT SUBCLASS 92 / 222
.~.~ Specific or diverse material; or welded, brazed or soldered joint

Current as of: June, 1999
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92 /   HD   EXPANSIBLE CHAMBER DEVICES

172  DF  PISTON {19}
208  DF  .~ Open-ended hollow skirt type (e.g., trunk type) {15}
222.~.~ Specific or diverse material; or welded, brazed or soldered joint {4}
223  DF  .~.~.~> Coated
224  DF  .~.~.~> End face and skirt periphery of diverse material
225  DF  .~.~.~> Element of diverse material for limiting radial movement of skirt part {3}
231  DF  .~.~.~> Welded, brazed or soldered (260)

DEFINITION

Classification: 92/222

(under subclass 208) Apparatus in which the piston or a portion thereof is composed of (1) two or more different materials (2) a single material which has been treated to provide portions of the piston with specific properties which

are different from the properties of another portion thereof (3) a specific material or (4) a welded brazed or soldered joint.

(1) Note. Under part (3) the mere recitation that the piston is formed of iron, steel or aluminum is excluded since such subject matter is extremely common in this art. However specifying, for example, a combination iron and steel or iron and aluminum, or a specific alloy is included.

SEE OR SEARCH THIS CLASS, SUBCLASS:

195, for an open ended skirt-type piston provided with a separate spring member for biasing a portion of the skirt radially, said spring member being normally formed of material which is different from the material forming the piston.

211, for an open ended skirt-type piston provided with an element of diverse material extending through a wall of the skirt, and abutting against a circumferentially extending resilient ring positioned on the outer periphery of the skirt.

212, for an open ended skirt-type piston provided with a nonmetallic portion. 213, for an open ended skirt-type piston in which the end face surface has portions thereof formed of different kinds of material.

257, for a piston having a side wall portion interposed between separable axially spaced rigid members.

SEE OR SEARCH CLASS

420, Alloys or Metallic Compositions, appropriate subclasses for an alloy, per se. Class 420 also provides for a nominal piston made of a specific alloy.