P. R. Mallory & Co. v. Automotive Mfrs' Outlet, Inc.

45 F.2d 810, 1930 U.S. Dist. LEXIS 1547
District Court, S.D. New York·Decided February 10, 1930·Published·Cited by 6 cases

Opinion

GODDARD, District Judge.

This is a suit for alleged infringement of United States letters patent No. 1,089,907, dated March 10, 1914, issued to William D. Coolidge, assignor to the General Electric Company, for an “electrical contact.” The original application for the petition was filed December 17, 1912, as a division of an original application filed March 20, 1912. The patent, together with the right to sue and collect any damages by reason of past infringements, was assigned on August 17, 1925, by the General Electric Company to the Elkon Works, Inc., in which name the suit is instituted. In the interval between the institution of the suit and trial, plaintiff’s name was changed to Elko-n, Inc., and the suit duly continued under the plaintiff’s new name.

The defenses set up are want of necessary parties plaintiff, invalidity, infringement, laches.

The patent in suit concerns the construction of electrical make-and-break contacts. Its purposes as defined in the patent are as follows:

“My invention relates to- electrical contacts, particularly for rheotomes or other vibratory circuit making and breaking devices, -ordinarily used as sparking or igniting contacts for gas-engines, as circuit controllers, for regulators, and for other like purposes.”

There are seven claims, in the patent, all of which are alleged to be infringed, reading as follows:

“1. An electrical make-and-break contact of tungsten.

“2. An electrical make-and-break contact of malleable tungsten.

“3. An electrical make-and-break contact of tungsten, and a backing for the same of a metal of superior electric and thermal conductivity intimately joined thereto.

“4. An electrical make-and-break contact of tungsten integrally joined to a metal backing- of superior electric and thermal conductivity.

“5. An electrical make-and-break contact of tungsten, a support for the same and a contact backing of a metal of superior electric and thermal conductivity intervening between'the contact and support and integrally joined to both.

“6. An electrical vibratory make-and-break contact of tungsten.

“7. An electrical make-and-break impact of tungsten.”

Just what problem Coolidge attempted to solve and his solution of it is best set forth in the specification of his patent, which reads as foEows:

“In apparatus of this character, vibratory contact terminals of expensive metals, such as platinum and iridium, have hereto-[811] lore been used, and it was found that these contaets deteriorated and became destroyed, so as to be unfit for further use, within a comparatively short time. The contacts were found to blacken and pit; their contacting surfaces became deformed by the continuous hammering action and by the formation of irregular and variably distributed small protuberances due, probably, to the transference of material from tho cathode to the anode, whereby the normal distance between the contacts was reduced and ‘bridges’ were often formed between the two contacts. It was also found that the accidental wetting of the contacts with oil seriously interfered with their operation. In addition to this, the materials heretofore used for vibratory contacts are softened by the heat of tho sparks passing between them, to such an extent as to cause welding, or incipient welding.”

“My invention is designed to overcome those difficulties and it consists broadly in make and break contaets of metallic tungsten, preferably in tho wrought or malleable form.

“It is a well-known fact that tungsten, when heated to redness in air, is soon covered with a layer of oxid which is practically an insulator, especially in the cold state, and this' property of tungsten would seem to make this material unfit for use as contacts. But I have found by experiment that this is not so, and that by reason of the light powdery or iloeeulent condition of the oxid, the samo is shaken off almost as quickly as it is formed, so that vibratory contacts of tungsten, and especially of wrought or malleable tungsten, can be used with great advantage.

“I have found that the pitting of the contacts made of tungsten, while theoretically not absent, is practically insignificant; that the normal distance between the contacts remains sensibly constant during a long period ; that no welding or incipient welding of the contacte occurs, and that the presence of oil on the contact surfaces does not interfere ■with their operation. In consequence of these properties of tungsten which I have ascertained by long continued experiments, contaets of this material have a very much longer life than contacts made of any other material known to me, or of any material that has heretofore been used.

“In a comparative test, I have found that a pair of tungsten contacts, after having made thirty-two millions of makes and breaks, were still clean and symmetrical, and apparently as good as new; while a pair of platinum contacts operated under the same conditions and with the same number of makes and breaks, wore found to have become so badly pitted, consumed and deformed as to be unfit for further use.

“One of a pair of contacts is usually mounted on a resilient support, such as a spring, and the other to a rigid support, and tho joinder between the contacts and supports should be very intimate so that the contacts will not become loose by the hammering action to which they are subjected. I secure this result either by fusing to one face of the tungsten contact a backing of a rather bulky piece of a metal of superior conductivity for beat and electricity, such as copper, silver or gold, and fasten the backing to a spring or rigid support by screws or other mechanical means; or I interpose the backing of superior conductivity between the contact and tho support by fusion to both, that is to say, by using the backing as a solder. In either ease, the beat generated in the contact is carried away rapidly.”

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P. R. Mallory & Co. v. Automotive Mfrs' Outlet, Inc., 45 F.2d 810, 1930 U.S. Dist. LEXIS 1547 (S.D.N.Y. 1930).

45 F.2d 810 (P. R. Mallory & Co. v. Automotive Mfrs' Outlet, Inc.) — published by Counsel Stack Legal Research, free access to 12M+ legal documents.

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