US PATENT SUBCLASS 338 / 217
TAPERED ELEMENT
Current as of: June, 1999
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DEFINITION
Classification: 338/217
(under the class definition) Subject matter wherein a physical dimension or characteristic of the element changes in one direction gradually or in a plurality of discrete progressive steps along the element from one terminal towards the other.
(1) Note. Usually the change in physical dimension or characteristic is for modifying the resistance value along the element between terminals, or to maintain this value uniform along the element between terminals to compensate for some other effect. The change must occur progressively in
one direction, and as a minimum must occur in two distinct steps.
(2) Note. Class 219, Electric Heating, especially subclasses 538+, provides for resistors having a shape, configuration, or arrangement to produce a particular pattern of heat distribution. However, as between this class (338) and Class 219, the mere recitation of the term "tapering" or the equivalent as a characteristic of the resistance element does not preclude classification in this class (338). For classification in Class 219 a more detailed recitation of the shape of the resistance element is necessary as having a plurality of tapers one at each end of the element, or a plurality of elements arranged with a tapered spacing, and resulting in a particular heating pattern.
(3) Note. Examples of the subject matter of this subclass are resistors whose elements are formed as a coating with the coating thickness progressively increasing or decreasing, resistors wherein the chemical composition of the element gradually changes over its length, and resistors whose element has a gradually changing physical dimension.
SEE OR SEARCH THIS CLASS, SUBCLASS:
89+, for mechanically variable resistors wherein some significant mathematical relationship lies between the mechanical adjustment or variation and the resistance value. 138+, for tapered mechanically variable resistors.
216, for resistors in a coaxial transmission line or wave guide, which resistors may be tapered.
333, for resistors of a particular configuration.
SEE OR SEARCH CLASS
219, Electric Heating, especially
538+, for resistors having a shape or arrangement to produce a particular heating pattern. See also (2) Note above.
333, Wave Transmission Lines and Networks,
9, and 34, for impedance matching coupling networks which may include a tapered resistor.
