Definition

GENERAL STATEMENT OF THE CLASS SUBJECT MATTER:

A. This class includes electrical resistors as above defined with solid, granular, or liquid resistance elements. These resistors may be either fixed or variable in resistance value, examples of the latter being rheostats and potentiometers. Semiconductors are included if limited by claimed subject matter to resistance properties, such as exists in photoconductive and thermistor type resistors. Excluded are conductors and insulators, which while including a resistive characteristic have other predominating characteristics.

B. Included also are resistors with perfecting structure not elsewhere classified such as resistors whose resistance value is temperature compensated, or resistors mounted on wheels or on a vehicle, resistors with heat dissipating projections, or with cooling gas or liquid circulation, or with heat storing, or with inductance or capacity reducing, or with electrical shields, or with a cleaner or a setting indicator in a mechanically variable resistor, or with a casing or housing, or with protecting structure spaced from the element, or with mounting or supporting means.

C. Included also are resistors combined with or incorporated in other structure not elsewhere classifiable, such as resistors with certain diverse nonelectrical devices, for example, mechanical or chemical; or resistors in, on, or with certain electrical devices such as a lamp socket or lamp base, or an electric switch, or a coaxial line or wave guide, or a detachable electrical connector.

D. Included also are resistors constructed as by shape or from material to change their resistance value particularly well in response to a particular condition or change in a particular condition such as current and/or voltage, as for example nonlinear and negative resistors; or ambient temperature; or a magnetic field; or gas, vapor, or moisture; or resistors of the strain gauge or photoconductive type. Included also are resistors usually of the mechanically variable type together with a condition sensing actuator which changes the mechanical adjustment of the resistor in response to a condition or a change in condition. Examples of such actuators are a magnetic compass, a float, a piston, a Bourdon tube, a bellows or capsule, a diaphragm, a gravity stabilized or inertia type actuator, or a force sensing actuator.

E. Subcombinations and components of resistors not otherwise classifiable, such as resistance element cores and frames, resistance elements of particular shape or dimensions, and movable contact structures for variable resistors.

Lines with other classes and within this class

Certain devices, at least quasi-resistive in character, are not classified here. Electric space discharge devices which may exhibit a resistance characteristic between terminals are classified elsewhere. Numerous different types of active solid-state devices, e.g., semiconductor, devices or components whose electrical resistance varies nonlinearly due to the movement of charge carriers - electrons or holes - which undergo energy level changes within the material (as contrasted with the passive or pure resistors found in Class 338) are classified elsewhere. Negative resistors of the active element type are classified elsewhere. Resistors specific to telephone use, including those of the microphone, its electrodes, and granules are classified elsewhere. (See References to Other Classes, below.)

(1) PLURAL RESISTORS AS DEFINED IN THE CLASS DEFINITION

Two or more mechanically or electrically related resistors are classified here as a residual home. For plural photoconductive resistors; plural separate diverse resistors; plural mechanically adjustable resistors; plural incased, embedded, or housed resistors; and for plural supported resistors see Subclass References to the Current Class, below. Regulation systems including a plurality of resistors are classified elsewhere. (See References to Other Classes, below.)

(2) RESISTORS COMBINED WITH OR INCORPORATED IN OTHER DEVICES:

As stated in the Class Definition, E, above, this class includes resistors combined with or incorporated in other structure when not elsewhere classifiable. For resistors with a restricted type of heat reflector; for a resistor with a diverse nonelectrical device, e.g., mechanical or chemical; for resistors in or on a lamp socket or base; for a resistor with a switch; for a resistor in a coaxial line or wave guide; and for a resistor in a detachable electrical connector see Subclass References to the Current Class, below.

The combination of the resistor with or in other structure is very common. A partial list of the classes and subclasses including this combination is given in References To Other Classes, below, referenced to this section.

(3) RESISTANCE COMPONENTS AND SUBCOMBINATIONS:

As stated in the Class Definition, E, above, this class includes subcombinations and components of resistors not otherwise classifiable. For contact structure adapted to move along the length of a resistance element in a mechanically variable resistor and making an electrical connection with the element; resistance element cores and frames; and for resistance elements and bases of particular configuration and/or dimension see Subclass References to the Current Class, below. In References to Other Classes, below, see the references to this section for the classification of the more common subject matter which may constitute a part or subcombination or a resistor.

(4) DEVICES SIMULATING RESISTORS:

Dissipating terminations for long lines; artificial lines; negative resistance networks of the active element type; and for resonators of the distributed parameter type are classified elsewhere. (See References to Other Classes, below.)

(5) METHODS OF AND APPARATUS FOR MAKING RESISTORS:

This class does not provide for methods of making resistors. This subject matter is classified elsewhere, (A) when involving a metal working process; or (B) when involving a metal working process combined with a nonmetal working process, if not otherwise classifiable; or (C) when the process is not otherwise classifiable. See References to Other Classes, below, for a field of search for methods of making resistors. Apparatus for assembling electrical resistors are classified elsewhere. Methods and apparatus for making a resistor coil which is a composite of a core and a winding thereabout are classified elsewhere. (See References to Other Classes, below.)

(6) MEASURING AND TESTING RESISTORS:

This class does not provide for either methods of or apparatus for measuring and testing resistors. If the measuring or testing involves determining the resistance or conductivity of the resistor, classification is elsewhere. If the measuring or testing is of a mechanical nature or not otherwise classified, classification is elsewhere. See elsewhere for a field of search for measuring and testing. (See References to Other Classes, below.)

(7) ELECTRICAL RESISTANCE HEATERS:

Resistors classified in Class 338 in performing their current impeding function produce heat, as do the resistance heaters classified in Class 219, Electric Heating. In the resistors classified in Class 338 the heat produced is incidental or undesired; or is utilized internally only to modify in some manner, as in a thermistor, the temperature of the resistor to in turn modify the current impeding characteristic of the resistor. In the resistance heaters classified in Class 219 the heat produced is put to some external use as opposed to mere dissipation or internal heating of the resistance element. Thus, in general, the resistance heaters in Class 219 include significant structure, shape or arrangement to produce and convert the heat to a useful purpose, as to direct or distribute the heat in a particular manner. The following paragraphs cover the more common situations arising between these two classes.

(A) The mere designation of the claimed structure as a heater or heater element, such a toaster or a blanket, or the broad recitation in the claim of intended use or adaption for heating purposes or for use with structure to be heated is not sufficient for classification in Class 219.

(B) The recitation of the device to be heated in combination with the heating resistor is classified in Class 219 rather than in Class 338. Likewise classification is in Class 219 when the resistor is shaped or otherwise adapted to conform to the structure to be heated to facilitate the transfer of heat to this structure, such shape or adaption not having general utility.

(C) The combination of a resistor and a casing of good heat conducting material is classified in Class 338. For classification in Class 219 as indicated above the heating resistor with its casing must be adapted as by shape to transfer, distribute, or direct the heat in a particular manner or pattern.

(D) Resistors whose elements are formed as fabrics or pads are classified in Class 338. However, if the fabric or pad is shaped or dimensioned to constitute a particular heating device, such as an article of clothing or a blanket classification is in Class 219. Mere fabrics including metal of resistance material, as when the resistance terminals are not claimed is classified elsewhere.

(E) The combination of a resistor and structure to facilitate the external heating effect of the resistor, such as a reflector, is classified in Class 219. Likewise Class 219 includes those resistors which are shaped to produce a desired heating effect or distribution. Resistors including reflectors which direct heat on the resistance element are classified herein (see Subclass References to the Current Class, below).

(F) A few structures such as liquid resistance heaters and liquid cooled resistors, may be considered either resistance heaters for Class 219 or resistors for Class 338. These structures are classified in accordance with the recited use and background.

(8) RESISTANCE FURNACES:

Electric furnaces combined with the heating resistors, as a resistor with the furnace wall; or includes resistors which are formed to constitute at least part of a furnace, as being hollow to form a muffle or being recessed to form a crucible; or includes resistors which are peculiar to an electric furnace, as having the shape of the furnace, such shape having no significance elsewhere are classified elsewhere.

(9) RESISTORS FORMED BY COATING OR LAMINATING:

Processes of forming electrical products when formed by a coating process, per se, and when formed by a laminating step, per se, are classified elsewhere. A plurality of layers of laminated or coated material, one layer being a resistance element and the other layer or layers being terminals, no particular structure being recited, but usually only particular materials, are classified elsewhere, even though the terminals and resistance elements are claimed by such names. See this class (338) for a resistor whose element is coated on a base and for resistors with terminals coated on, together with significant resistance structure such as a particular shape. (See Subclass References to the Current Class and References to Other Classes, below.)

(10) CONDUITS, CABLES, AND CONDUCTORS WITH RESISTIVE MATERIAL:

Conduits, cables, and conductors where the conducting part is a resistor or a helical resistor are classified elsewhere. Such claimed terms as resistance, resistance element, helical resistance, coil resistance, or a terminal at one end of a sheathed resistor do not preclude classification elsewhere. However, when the conducting element in such conduits, cables, or conductors is recited as being of a material which is essentially resistive such as iron, classification is in Class 338. Likewise when significant resistance structure or configuration such as the resistor having a zigzag pattern, or being wound on a core is recited, classification is in Class 338. Conduits, cables or conductors with a nominally resistive or helically resistive element together with end structure and cables whose conducting elements are nominally resistive or helically resistive are classified elsewhere. The claimed combination of a resistor broadly with end structure or terminals at each end is classified in Class 338.

(11) ELECTRICAL CONNECTORS WITH RESISTIVE CONDUCTORS:

The combination of an electrical connector and lead conductor, the lead conductor being nominally claimed as being resistive, is classified elsewhere. If the lead conductor is recited as being of significant resistor structure or material, such as a zigzag shape or of iron material, classification is in Class 338. The combination of a nominally recited resistive conductor with an electrical connector at each end is classified in this class (338) . The inclusion of additional connectors cooperable with the connector or connectors on the resistance element does not preclude classification in Class 338. (See Subclass References to the Current Class and References to Other Classes, below.)

(12) SEMICONDUCTORS:

Semiconductors are classified in Class 338 if possessing only resistance characteristics. Such semiconductors may be photoconductive or may be of the thermistor type (see Subclass References to the Current Class, below). However, if the semiconductor has other more comprehensive characteristics, classification is elsewhere. Numerous different types of active solid-state devices, e.g., semiconductor, devices or components whose electrical resistance varies nonlinearly due to the movement of charge carriers - electrons or holes - which undergo energy level changes within the material (as contrasted with the passive or pure resistors found in Class 338) elsewhere. (See References to Other Classes, below.)

(13) MEASURING AND TESTING DEVICES WITH VARIABLE RESISTORS:

This Class 338 provides generally for resistors which are shaped or chemically constituted to change their resistance value in response to a condition or change in condition, or for mechanically variable resistors combined with a condition sensing actuator. However, when additional structure is claimed for indicating the change in resistance value as a meter for measuring the current passing through the resistance element, or a Wheatstone bridge arrangement including the resistance element as one of the arms, the combination is classified as a measuring or testing device. Distance measuring devices and gauges, namely, a condition responsive resistor and an indicating device or circuit are classified elsewhere; moisture content and stress and strain measuring devices, dynamometers, liquid level or depth gauges, hygrometers, and fluid pressure gauges including this combination are classified elsewhere; a thermometer including this combination is classified elsewhere; and time and/or speed measuring devices including this combination are classified elsewhere. See References to Other Classes, below. See also the reference to Class 338 in References to Other Classes in the Class Definitions of Class 73.

(14) RESISTANCE COMPONENTS AND SUBCOMBINATIONS:

This class (338) provides for resistance components and subcombinations which are not otherwise classifiable. This class (338) includes resistance cores or frames including a base usually of insulating material on which a resistance element may be wound or otherwise strung. As between this class (338) and the insulators of special application in other classes, this class (338) includes insulators which are constituent parts of the resistor as to have a resistance element wound or strung thereon. However, an insulator for supporting a resistance wire at one point thereon, this wire being strung in space in the manner of an aerial conductor is not classified here, but elsewhere. Resistive cable supports and brackets are classified elsewhere.

Boxes and housings which may constitute resistor housings which are limited by claimed structure to electrical use and not otherwise classifiable are classified elsewhere.