Bourns

Action for infringement of patent No. 2,515,981, issued to M. E. Bourns on July 18, 1950. The defendants have denied infringement and have attacked the validity of the patent. ' No claim of invention by them is asserted by the defendants. Their challenge of the validity of the patent is based on claimed anticipation.

I

The Validity of the Patent in Suit.

The issues, as narrowed by the proof, concern the validity of the single claim of the patent, which reads:

The invention is denominated an “adjustable resistor”, and is known in industry as a “potentiometer.”

The inventor has illustrated his invention in two embodiments. (See illustrations.) The validity of the claim is challenged. The challenge lacks merit.

*505

A potentiometer is an electro-mechanical. device containing a resistance element that is contacted by a movable slider. (See F. E. Dole, Potentiometers in “Components Handbook,” ed. by John F. Blackburn, 1949.) The patented device is a linear type.

The problem which confronted the art is stated in the specifications in this manner:

The problem was met by the inventor by providing (a) an adjustable resistor of simple structure that would respond with precision to…