Court Opinion

ID: 6871101
Source: CourtListenerOpinion
Date Created: 2022-07-23 21:01:16.369529+00
Date Added: 2024-06-11T16:05:24.553793
License: Public Domain

On Petition for Rehearing.
PER CURIAM.
In its petition for rehearing, the defendant urges strongly that we misconceived the prior art; that Holtz did no more than to embody its teachings in a self-starting sub-synchronous motor of constant speed when the demand for such a motor arose; and that the monopoly which he seeks far exceeds any reasonable relation to the contribution to the art which he made. These questions have been carefully- re-examined.
It is alleged that we fell into error in assuming that the Tesla patent was considered by the Patent Office or the Court of Customs and-Patent Appeals; that it was not considered; and that “accordingly the presumption of validity arising from the grant of the patent is worthless”; that “the Tesla patent taken with the Tesla publication shows that Tesla taught the public in 1894 the very tiling to which the court ascribes the success of the Holtz patent.” The Tesla patent is urged as a complete anticipation of Holtz. The Tesla publication is quoted:
"If it is desirable to secure a constant speed, and at the same time a certain effort at the start, this result may be attained in a variety of mays. For instance, two armatures, one for torque and the other for synchronism, may be fastened on the same shaft and any desired preponderance may be given to either one, or an armature may be wound for rotary effort, but a more or less pronounced tendency to synchronism may be given to it by properly constructing the iron core; and in many other ways.” (Italics supplied.)
And also the Tesla patent:
“In such an arrangement as this, it is obviously desirable for economical and other reasons that a proper retention between the speeds of two motors should be observed.”
The Tesla device to which these quotations refer consisted of two motors side by side on the same shaft with separate fields, and separate rotors. One motor had a rotor Of the “torque,” or induction, type; the other of the reaction, or “synchronizing,” type. There was an arrangement to switch the current from one set of fields to the other after the motors had been started — although it was stated that this was not essential and both fields might be left in circuit. The polar projections of the synchronizing armature were wound with closed coils. It is a long way from the Tesla device to the simplicity and effectiveness of Holtz. We are wholly unable to agree that the Tesla patent and the publication referred to anticipated in an inventive way the simple compact structure of the Holtz motor. Undoubtedly it was known before Holtz that reaction rotors - could be made which when brought nearly up to the speed of an alternating current would lock into step with it. Coerper explains and shows this. The observation quoted from this patent in the opinion states the general view of the art three years after'the Tesla patent (1891). The Warren patent also refers to the general understanding of the art many years later. One difficulty with such motors appears to have been that they'had very little torque, i. e., very little power to overcome resistance. The Holtz rotor provides in a single element the torque essential to overcome resistance and maintain the desired speed, and at the same time subjects this torque to the locking-in power of the reaction element. The suggestion in the Tesla publication that this could be done by two armatures and that in a single armature “a more or less pronounced tendency to synchronizism may be given by properly constructing the iron core” can by no means be regarded, as anticipation of the Holtz device. It seems to us much more than an obvious application of well-known principles.
At the hearing in the District Court efforts were made to show that motors built according to prior patents would perform like the Holtz motor. They were unsuccessful. The finding of the District Judge on this point referred to in our opinion is high*477ly significant on the practical state of the prior art.
The facts show clearly that, as was said in the opinion, there was a potential demand for a motor having the Holtz characteristics as soon as public lighting circuits were standardized and accurately timed.
The allegation in the petition, that the defendant’s difficulties in designing a motor were erroneously stated in the opinion and that its employee Fink designed one promptly in 1928 when the problem was presented to him, ignores the facts that only six of the Fink motors were ever built and none of them was ever sold. Clearly the Fink motor did not solve the problem, and the defendant’s employees continued their efforts. The challenged statement is accurate.
By inadvertence, shaded poles were incorrectly described in the opinion on page 473. The sentence beginning, “Such motors consist of field or stationary magnets having what is called shaded poles” is changed to read:
“Such motors consist of field or stationary magnets having what is called ‘shaded’ poles, i. e., poles each of which is divided, one part of the face of the pole being shaded from the armature.”
In other respects the statements of fact in the opinion appear to be correct. And upon careful re-examination, our conclusions of fact and our rulings of law appear also to be correct. The Holtz invention lay in devising a motor having a single field and also a single rotor or armature in which were combined an induction element which made it self-starting and provided torque to keep it up to speed against frictional or other resistance, and a reaction element which controlled the speed and kept the rotor in step with the alternations' of the current. This had never been done or described before Holtz, and we think it involved invention.
This view of the Holtz patent may require discrimination between its claims. Some of those in suit may not be valid. There has been no finding on this point by the trial court and it was not argued before us. Instead of remanding the cause with instructions to decree for the plaintiffs on all the claims in suit, it will be better, we think, to vacate the decree of the District Court and remand for further proceedings not inconsistent with the opinion, including as part of it this memorandum.
The decree of this court of June 30, Í937, is vacated. The decrees of the District Court are vacated, and the case is remanded to that court for further proceedings not inconsistent with the opinion of June 30, 1937, as modified by this opinion. The appellants recover costs of appeal. The petition for rehearing is denied.