Tesla Split-Phase Patent Litigation

An opinion has been rendered by the United States Circuit Court of Appeals for the Third Circuit (Western Pennsylvania) in a suit involving the Tesla split-phase patents, in which he Jefferson Light, Heat & Power Company was alleged to have infringed these patents in having used a meter involving the split-phase principle. The case had previously come before the court on an appeal from an order granting a preliminary injunction. This order of the lower court was reversed pending a plea that the case was res adjudicata in view of a decision rendered in the United States Circuit Court of Appeals sitting in New York in the case of the Catskill Illuminating & Power Company, the decision of this court being that the Tesla split-phase patents were invalid through anticipation. Subsequently the present cause proceeded to a hearing, resulting in a decree overruling the bill of res adjudicata, declaring infringement and granting an injunction. From that decree the defendant appealed on the ground that inasmuch as the Catskill case was defended by the Diamond Meter Company, and the present case is defended by the same company, the Catskill case was res adjudicata of everything involved in the present case. The opinion was written by Judge Acheson, and the court held that the Diamond Meter Company did not avowedly or openly conduct the defense in the Catskill case, and having concealed its connection with the case while it was pending, it is now too late for it to set up the decree in that case as an estoppel against the complainant in the present case. The plea was overruled and the granting of a preliminary injunction by the court below affirmed.

The United States Circuit Court of Appeals for the First District in a suit involving also the Tesla split-phase patents, in which the Stanley Instrument Company was the defendant, has denied a petition of the latter to file a supplementary bill in the nature of a bill of review, or to amend the judgment on appeal. In this case the lower court decided against the split-phase patents and was reversed on appeal. Application was then made to the Supreme Court for a writ of certiorari on the grounds of conflict with the action of the Catskill case, which was denied. The petition of the present cause was based on the grounds that certain English Tesla patents on identically the same subject matter as the patents in suit expired in 1903, and that this expiration was a complete defense as against the patents in suit. The court held that since the foreign patents expired only a few days after the decree was entered in the lower court and before the appeal was heard, the question of laches on the part of the petitioner could not be wholly overlooked. The court held, however, that the merits of the case with respect to the identity of the foreign and American patents are so clearly against the petitioner that it was not necessary to pronounce on the question of laches. In order that the term of a foreign patent may be limited by a domestic patent, it is essential that the inventions covered by the two patents should be identical. This is not true with respect to the patent cited in this suit. While it is true that one claim of the British patent necessarily includes all the elements of the American patents, it also includes other elements establishing a new combination which is an essential, novel and patentable improvement on what was claimed in the patents before the court on appeal. This claim covers not only the mere improvement on either split-phase invention or polyphase invention separately, but it covers an invention by which a convertable motor is produced. This necessarily takes the case out of the field of identity with either the earlier polyphase or the later split-phase patents. The petition was denied.