Riester:Graver Tank & Mfg. Co. v. Linde Air Products Co. 339 US 605 (1950)

Supreme Court of the United States GRAVER TANK & MFG. CO., Inc., et al. v. LINDE AIR PRODUCTS CO.

No. 2. Reargued March 30, 1950. Decided May 29, 1950. Motion to Issue Mandate Denied June 5, 1950.

• The Linde Air Products Company brought action for patent infringement against Graver Tank & Manufacturing Company and others

• A judgment holding certain claims of plaintiff's patent invalid and holding other claims valid and infringed was entered by the United States District Court, Northern Division of Indiana and upon appeal the portion of the judgment holding certain claims invalid was reversed by the Court of Appeals for the Seventh Circuit and the defendants brought certiorari.

• The judgment of the Court of Appeals insofar as it reversed that of the District Court was reversed and judgment of the District Court was reinstated by the Supreme Court

• thereafter a rehearing was granted limited to the question of infringement of the four valid flux claims 18, 20, 22 and 23 in plaintiff's patent No. 2,043,960, relating to electric welding. The Supreme Court, Mr. Justice Jackson, held that finding that the four flux claims of plaintiff's patent were infringed by defendants' device under doctrine of equivalents was not clearly erroneous.

Affirmed.

• basically, patents must protect against insubstantial changes, otherwise theyre worthless. It is also inconceivable to outline or detail every possible manifestation or variation in a patented design. Thus this kinda of duplication must constitute patent infringement.

• The doctrine of equivalents evolved in response to this experience. The essence of the doctrine is that one may not practice a fraud on a patent. Originating almost a century ago in the case of Winans v. Denmead, 15 How. 330, 14 L.Ed. 717, it has been consistently applied by this Court and the lower federal courts, and continues today ready and available for utilization when the proper circumstances for its application arise. ‘To temper unsparing logic and prevent an infringer from stealing the benefit of the invention'[1] a patentee may invoke this doctrine to proceed against the producer of a device ‘if it performs substantially the same function in substantially the same way to obtain the same result.

• "What constitutes equivalency must be determined against the context of the patent, the prior art, and the particular circumstances of the case"

• A finding of equivalence is a determination of fact. Proof can be made in any form: through testimony of experts or others versed in the technology; by documents, including texts and treatises; and, of course, by the disclosures of the prior art.

• "In the case before us, we have two electric welding compositions or fluxes: the patented composition, Unionmelt Grade 20, and the accused composition, Lincolnweld 660. The patent under which Unionmelt is made claims essentially a combination of alkaline earth metal silicate and calcium fluoride; Unionmelt actually contains, however, silicates of calcium and magnesium, two alkaline earth metal silicates. "

DISSENT

Claims arent specific enough. Congress said something or other limiting patent monopoly to what is specifically outlined in the claim.

Notes

• The dissent here doesn't make much sense. The judge is too hung up on the letter of the law and is not understaning the spirit of patent law.