Halliburton v. Walker

Citation: Halliburton Oil Well Cementing Co. v. Walker, 146 F.2d 817, 64 U.S.P.Q. (BNA) 278 (9th Cir. 1944).

The court ruled that a method patent for determining the unknown location of an obstruction in a well was invalid for want of invention, finding that its novelty lie only in the performance of certain mental steps. The steps involved were described in the claims by such descriptive words as “determining,” “registering,” “counting,” “observing,” measuring,” “comparing,” “recording,” and “computing.”

In ruling the patent invalid, the court reasoned that, in substance, the claimed method consisted of setting down three known values in a simple equation and then computing the unknown value.