Westinghouse Lamp Co. v. C. E. Mfg. Co.

32 F.2d 615, 1 U.S.P.Q. (BNA) 190, 1929 U.S. Dist. LEXIS 1218
CourtDistrict Court, D. Rhode Island
DecidedApril 20, 1929
DocketNo. 261
StatusPublished

This text of 32 F.2d 615 (Westinghouse Lamp Co. v. C. E. Mfg. Co.) is published on Counsel Stack Legal Research, covering District Court, D. Rhode Island primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Westinghouse Lamp Co. v. C. E. Mfg. Co., 32 F.2d 615, 1 U.S.P.Q. (BNA) 190, 1929 U.S. Dist. LEXIS 1218 (D.R.I. 1929).

Opinion

LETTS, District Judge.

The Westinghouse Lamp Company brings this suit in equity against the C. E. Manufacturing Company, Inc., for infringement of letters patent No. 1,180,264 issued to Anton Lederer of Vienna, Austria, April 18, 1916, upon an application filed December 20, 1906. The bill contains the usual prayers for relief by injunction and for damages.

The plaintiff company at Bloomfield, N. J., is a manufacturer of electric lamps and radio tubes. It claims to be the owner of said letters patent, and alleges that the defendant company, which is also engaged in the manufacture of radio tubes at Providence, R. I., has infringed and is infringing upon said patent in making its type A tube. No other product of the defendant company is involved in this suit.

It is agreed that the general design and performance of the 201-A tube of the plaintiff and the type A tube of the defendant are substantially the same. Each tube em[616]*616bodies a “hairpin” filament, taking the form of an inverted Y surrounded by an elliptical plate with a grid interposed between the filament and the plate. Both tubes operate on a five to six volt one-quarter ampere current and give an emission of approximately 50 milliamperes. In fact, this type of tube appears to be made by many manufacturers. In the trade the design 201-A has become substantially a generic or descriptive designation of a tube of a given type.

Neither the plaintiff nor the defendant was the first in the field in its manufacture. The plaintiff began the manufacture of radio tubes in the year 1921, and the defendant began its manufacture some time in 1925. The plaintiff complains, however, that the patent here involved covers the thoriated tungsten filament used by it and that the defendant is also using a thoriated tungsten filament of substantially the same, structure and composition.

A word should here be interposed in explanation of the structure of these filaments and the reason therefor. In the construction of a radio tube of the type involved in this controversy the principal object to be attained is that of electronic emission, together, of course, with necessary durability. In the development of the radio tube industry it was found that most pure metals and carbon when heated at varying temperatures emitted electrons.

The original De Forest tube was constructed with a substantially • pure carbon filament.' It was found, however, that the efficiency of a tube was infinitely increased by employing a filament composed of tungsten with an admixture of a very small percentage of thorium. Thorium is a rare earth metal which is found to be used commercially, both in its metallic form (Th) and as an oxid (ThO2) in which latter state it appears as a gray powder.

The presence of ThCte in the body of the filament does not increase the electronic efficiency of the filament, but the emission is greatly increased by the presence of a very slight percentage of thorium; the electronic emission being thereby increased about twenty times.

The patent in question is entitled “Incandescent Body for Electric Lamps.” In the introductory paragraph of his specification the inventor states that:

“My invention relates to certain improvements in filaments for incandescent electric lamps, in particular such filaments as are essentially composed of metals that tend to alter internally under the influence of elec-trie currents and to the process of manufacturing the same.
“It consists generally in the production of more durable and efficient incandescent filaments, containing an intimate mixture of such a metal with another metal or metallic compound which causes the filaments to resist internal alterations during their use.
“In the manufacture of filaments for incandescent lamps, and especially of filaments consisting of pure tungsten metal, it has been observed that, after burning .for some time, an alteration in the structure of such filaments takes plaee. This alteration, which manifests itself in a displacement of sections of a filament with respect to its longitudinal axis, is usually designated by the terms ‘offsetting’ or ‘faulting’, and is probably due to the crystallization of the metal. The appearance of this crystalline structure has the ' deleterious effect that it renders the filaments considerably more brittle than they were before and it thus increases very greatly the liability of the filaments breaking when the lamp is in service or is subjected to shocks.- I have discovered that by the addition of small percentages of suitable substances to the tungsten this crystallization and consequent deterioration of the filament can be largely obviated or entirely prevented. In one of the ordinary processes of manufacturing tungsten filaments it is usual to bring the tungsten metal, or an appropriate tungsten compound, into the shape of a plastie paste by means of an addition of a suitable binding material. I have found that when a small amount of oxygen or oxygen containing compounds of rare earth metals and like materials, such as thorium, zirconium, erbium, cerium, lanthanum, etc., is added to a paste of such a character, or to the materials used in making metallic fila^ ments according to other processes, the resulting filament is structurally different from a filament consisting only of tungsten and .that the change-over of the filament into the crystalline structure is considerably delayed or altogether prevented. The presence of a binding material, is, of course, immaterial, nor does it matter at what time during the process of manufacturing these additions are made to the tungsten metal or tungsten compound, as long as they produce the desired result in the finished filament.”

The inventor, after indicating that he has in mind a squirted filament, that is, a filament made from a paste forced through a die, which was in fact the only method of filament making known at the time, further states:

[617]*617“It will, of course, bo understood that my invention is not limited in its application to use in connection with any particular process of producing the filaments, but that, if desired, it may be employed in connection with any other process than that specifically set forth. It is also to be understood that my invention is not alone applicable to tungsten filaments hut that it is also applicable to all filaments suitable for incandescent lamps and subject to offsetting or faulting in use.”

In the concluding paragraph of the specification the inventor says:

“1 am aware that it has been proposed to make lamp filaments consisting of a mixture of a metal and an oxid, but, in such eases, the oxid forms a large part of the finished filament, whereas, in my process, the oxid or other metallic compound is added only in sufficient quantity to accomplish the desired result. This result is essentially the prevention of harmful internal alteration or ‘offsetting’, and the fact tlwet the addition of other substances than the filament metal will produce this result has never, so far as I am aware, been suggested prior to my present invention.”

The patent embraces a total of some 16 claims. Seven only of these are relied upon by the plaintiff. These seven claims are as follows:

“I claim as my invention:
“1.

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Cite This Page — Counsel Stack

Bluebook (online)
32 F.2d 615, 1 U.S.P.Q. (BNA) 190, 1929 U.S. Dist. LEXIS 1218, Counsel Stack Legal Research, https://law.counselstack.com/opinion/westinghouse-lamp-co-v-c-e-mfg-co-rid-1929.