General Radio Co. v. Watson

188 F. Supp. 879, 125 U.S.P.Q. (BNA) 268, 1960 U.S. Dist. LEXIS 4908
CourtDistrict Court, District of Columbia
DecidedFebruary 12, 1960
DocketCiv. A. No. 4459-56
StatusPublished
Cited by2 cases

This text of 188 F. Supp. 879 (General Radio Co. v. Watson) is published on Counsel Stack Legal Research, covering District Court, District of Columbia primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
General Radio Co. v. Watson, 188 F. Supp. 879, 125 U.S.P.Q. (BNA) 268, 1960 U.S. Dist. LEXIS 4908 (D.D.C. 1960).

Opinion

MORRIS, District Judge.

This is an action brought under 35 U.S.C. § 145 1 by the plaintiff, as the as-signee of an application for patent by one of its electrical engineers, Gilbert S. Smiley, for “Method of and Apparatus for Improving the Stability of Continuously Adjustable Transformers and the Like,” Serial No. 221,878, filed April 19, 1951, seeking to have the Court authorize the issuance to it of a patent. After the final rejection by the Patent Office exam[880]*880iner on February 15, 1955, of claims 15 and 23 through 33, the applicant filed on May 10, 1955, a proposed amendment substituting claim 34 for all such rejected claims. On May 17, 1955, the examiner refused allowance of claim 34, but entered it only for purposes of an appeal. The Board of Appeals (hereinafter referred to as the Board) on June 18, 1956, affirmed the examiner’s refusal of claim 34, the single claim before this Court, and which reads as follows:

“34. A variable-impedance auto-transformer having, in combination, a copper-wire single-layer substantially toroidal winding wound in successively disposed turns about an annular core to provide along the exterior of the winding a track extending across the successively disposed turns, there being bonded to the turns along the track coatings selected from the group consisting of gold, platinum, palladium, rhodium, silver and nickel, means for connecting the winding to a source of voltage, the winding being adapted to be connected also with a load circuit to exchange current with the load circuit at values not greater than a predetermined safe value above which the winding would become damaged by such exchange of current, and a carboniferous or graphitic resistive brush actuable along the track in contact with the coatings and adapted for connection with the load circuit, the width of the brush being greater than the distance between two successive turns of the winding in order that the brush may establish contact with the coating bonded to a turn before breaking contact with the coating bonded to the adjacently disposed turn with which it last contacted, thereby to prevent interruption of the current in the load circuit into the brush, means for connecting a point of the winding and the brush to the load circuit, and the brush being rotatable about the axis of the toroidal winding along the said track in engagement with the coatings of the successively disposed turns, the coatings maintaining the resistance between the brush and the track, during passage of the current of the predetermined safe value between them, substantially constant.”

The invention claimed herein consists of plating gold, platinum, palladium, rhodium, silver and nickel to the turns along the brush track of the device disclosed in application No. 2,009,013, of Karplus, et al., dated July 23, 1935 (of which plaintiff is also assignee, and which device has been manufactured and sold by it under the trade name of Variac, and by its licensees in this country and others under differing trade names, for many years), and of the discovery of the reason for the failure of the Karplus device, stated in the application as follows:

“It has been found, however, that when the apparatus is in continuous use, particularly at elevated temperatures and in regions where industrial vapors or other corrosive influences are present, the copper track detrimentally oxidizes, contaminates and corrodes, markedly and rapidly increasing, and thus rendering unstable, the resistance of the brush-to-copper-track interface. With long periods of continuous use, indeed, a progressively destructive cycle is often initiated in which the increasing oxidation, contamination and corrosion of the track during the use of the instrument increases the brush-to-track resistance which, [881]*881in turn, further increases the temperature at the contact between the brush and track, which still further increases the oxidation, contamination and corrosion, until failure or improper operation of the instrument results from the high temperature.”

The original autotransformer, on which Karplus was issued a patent, operated satisfactorily when used almost exclusively in laboratories, where the use was intermittent and the atmosphere clean. During and after World War II the transformer was employed more and more in industrial use, where the use was continuous and the atmosphere was contaminated. Then complaints became more and more frequent because the autotransformers were being burned out. Many methods were employed to eliminate or reduce these failures: The customers were instructed to keep the brush tracks cleaned by removing carbon particles and washing with carbon tetro-chloride, the brushes were redesigned, the heat radiators were redesigned, in 1946 a beryllium-copper brush spring was employed to obtain a uniform spring pressure on the brush, which lost tension under the “hot spot” temperature in the region of the brush, and which was substituted in 1949 with a stainless steel brush spring, efforts were made to cool the auto-transformer by blowing air on it, using a blower and a fan, and by oil cooling, pigtails, or conductors, were employed to carry the current from the block containing the carbon and to help carry the heat out of the block. All these efforts, it was testified, delayed the eventual burn-out of the tracks, but were not successful in preventing their ultimate destruction by such burn-out. In order to save face with its customers, plaintiff eventually supplied considerably larger instruments than the size indicated by the need of the customer. Mr. Smiley, whose assignee plaintiff is respecting the application here involved, testified that in 1948 (Tr. 86):

“ * * *■ we began to suspect that there was an action occuring that we hadn’t been able to explain by ordinary — these techniques that we said, the track got dirty from the brush, got dirty from contamination — but there seemed to be something more, and at that time I began to suspect that there was a formation of a high-temperature oxide, the cycle being initiated by some chance or haphazard occurrence, but once that cycle had been initiated it was a destuctive, a vicious circle of oxide forming, poor contact, more heat, more oxide, and this was the cause of burnout.
“So, the first thing we thought was to keep air away from the area around the brush and the track. At that time the Dow Corning Company announced a high-temperature silicone grease, and we tried it, and it seemed to help; it wasn’t perfect, but it certainly delayed burnout, and so we recommended it to our customers who were having burnout trouble.”

In addition to the above efforts to correct the apparent inherent destructive quality of the apparatus, attempted improvements in the iron core, around which the copper-wire forming the brush track was wound, were made in an effort to improve the thermoconductivity so as to lower the temperature of the “hot spot” and thereby reduce the total amount of heat generated in the transformer. This latter effort also failed to result in a solution of the problem. At this stage of developments, Mr. Smiley testified (Tr. 92-94):

“It occurred to me that since we— no matter what we tried to do we were getting this progressive high-temperature oxidation of the track, and this was a phenomena associated with copper, that if we could use some other metal than copper, it might be possible to find a metal that would work.

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Related

Superior Electric Co. v. General Radio Corp.
203 F. Supp. 864 (D. New Jersey, 1962)
Superior Electric Company v. GENERAL RADIO CORPORATION
194 F. Supp. 339 (D. New Jersey, 1961)

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Bluebook (online)
188 F. Supp. 879, 125 U.S.P.Q. (BNA) 268, 1960 U.S. Dist. LEXIS 4908, Counsel Stack Legal Research, https://law.counselstack.com/opinion/general-radio-co-v-watson-dcd-1960.