Johnson Laboratories, Inc. v. Meissner Mfg. Co.

98 F.2d 937, 1938 U.S. App. LEXIS 3369
CourtCourt of Appeals for the Seventh Circuit
DecidedAugust 1, 1938
Docket6023, 6136-6138
StatusPublished
Cited by16 cases

This text of 98 F.2d 937 (Johnson Laboratories, Inc. v. Meissner Mfg. Co.) is published on Counsel Stack Legal Research, covering Court of Appeals for the Seventh Circuit primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Johnson Laboratories, Inc. v. Meissner Mfg. Co., 98 F.2d 937, 1938 U.S. App. LEXIS 3369 (7th Cir. 1938).

Opinion

LINDLEY, District Judge.

The Johnson Laboratories, Inc., brought suit against the Meissner Manufacturing Company, for infringement of Claim 38 of Polydoroff Patent No. 1,982,690 and Claim 5 of Crossley et ah, Patent No. 1,978,568, both assigned to Johnson. The court held invalid Claim 5 of the Crossley patent and valid and infringed Claim 38 of Polydoroff. Each party, appealed from that part of the decree against it. The Ferrocart Corporation of America brought suit for a declaratory judgment under Section 274d of the Judicial Code, 28 U.S.C.A. § 400, to determine the questions of validity and infringement of seven of Johnson’s patents, including those involved in the first suit, and charged unfair competition by’ Johnson Laboratories, Inc., and Aladdin Industries, Inc. The two defendants thereupon filed their counterclaim against Ferrocart for infringement of four patents and for unfair competition. Ferrocart. appeals from a decree declaring valid and infringed Polydoroff Patent No. 1,982,690, involved in the *939 first mentioned suit, and holding that it had unfairly competed with Johnson and Aladdin. The latter appeal from that portion of the decree holding Crossley et al., Patent No. 1,978,568 included in the first mentioned suit, and Polydoroff Patent No. 1,982,689 invalid and decreeing that the two defendants had unfairly competed with Ferrocart.

Ferrocart maintains its office in New York and is a corporation of that state. It imports merchandise from Germany and exploits certain inventions in the radio art and sells to Meissner Manufacturing Company certain cores for use in high-frequency inductance devices. These two corporations were represented in the two suits by the same counsel and their interests are identical. The same is true of Johnson and Aladdin. The various appeals were argued as one and this opinion will dispose of the issues in each. It will be observed that two of the patents are involved in each of the two suits and that the decree of the court was the same with regard thereto in each cause, the first Polydoroff patent being held valid and infringéd and the Crossley patent invalid. The only other patent now involved is the second Polydoroff, which, in the second suit, was held invalid.

Polydoroff Patent No. 1,982,690, was applied for August 26, 1929, and issued on divisional application December 19, 1933.-Claim 38 only is involved. It covers “a high-frequency inductance device for use in resonant circuits, including at least one low-loss winding and a compressed com-minuted magnetic core having insulated particles small enough to pass through a screen having 300 meshes to the inch, the increase in the effective inductance of said winding due to said core being substantially greater than the increase in the effective resistance of said winding due to said core.” Such a device, as known to the electrical world, is, in ordinary language, one consisting of a number of turns of wire, whereby the resulting coil possesses the property of electrical inductance. If it is wound upon a non-magnetic core, it is commonly known as an “air-core inductance” ; if upon a magnetic core, of iron or other metal, as a “magnetic core inductance.” A resonant selective radio circuit, in which the patentee said his device was useful, is one tuned to distinguish between broadcasting stations with various adjacent frequencies. By the tuning, the receiver may obtain reception at one frequency and exclude broadcasters transmitting on adjacent but different frequencies.

The difficulty encountered by many workers in the art of such devices arose largely from the fact that all magnetic core devices inherently possess a quality not desirable in such a circuit, namely: electrical resistance, — inducing losses and tending to destroy selectivity of tuning. In practice, therefore, an inductance device adapted to the frequencies encountered in radio broadcasting will not work satisfactorily if the resistance quality is so great as to defeat the purpose. In other words, the ratio of inductance to resistance must be a useful practical one, — the inductance comparatively large and the resistance proportionately small. It had long been recognized that a magnetic core in a coil serves to increase the inductance but, due to the fact that so-called eddy currents circulate within the core and absorb energy, it likewise increases the resistance, and it seems to ‘have been largely accepted that the additional resistance due to the use of a magnetic core increases rapidly with increased frequency, though the increased inductance due to such a core is substantially independent of frequency. Consequently many in the art believed that such a magnetic core, which improves inductance at low frequency, will improve it to a lesser degree at a higher frequency and, if the frequency be increased sufficiently, becomes positively harmful. The problem, then, of makers of such devices, to be placed in radio receiving sets, was to produce, under the frequencies controlling in broadcasting, the highest possible practical inductance and the lowest possible interfering resistance.

It is insisted that Polydoroff was the first to solve the problem and in so doing achieved invention. His claim is limited first of all to a “high frequency” inductance device to be used in “resonant circuits.” He provides in his combination, first, a low-loss winding coil; second, a compressed com-minuted magnetic core having insulated particles, and, finally, the requirement that the particles shall pass through a screen having 300 meshes to the inch. This combination, he said, brought about an increase in the effective inductance of the coil winding, due to the magnetic core, substantially greater than the corresponding increase in the effective resistance of the winding, due to the core. He recognized that successful attempts had been made to employ magnetic cores but asserted that the losses from *940 increased resistance arising in their utilization had made impractical their use in high frequency radio transformers. He said that by using powdered-iron cores it was possible to decrease the size of the windings and thereby minimize the size of the transformers, thus sawing cost of space. He asserted that for the most satisfactory results “for frequencies between 1500 k. c. and 1000 k. c.” i. e., between 1,500,000 and 1,000,000 cycles, the builder should use iron “reduced by hydrogen,” consisting of particles which would fall freely through a screen of 300 meshes to the square inch. He recognized that coarser particles might be used for frequencies below 1,000 k. c. He stated that the fineness of the particles and, to some extent, the degree of compression determined the resistance of the coil and core combination.

It was well known prior to Polydoroff that losses in a ferromagnetic or iron core could be ’reduced by subdivision of the material into thin sheets. But Johnson insists that this prior use was confined to “low frequencies” namely: those of from 20 to 60 cycles. It was well known also that com-minuting or powdering the core material, producing still greater subdivision of material, which could be compressed, or molded into proper form with or without insulation, to form a compacted mass, was similarly useful but, again Johnson says, only for low frequency inductance devices.

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Bluebook (online)
98 F.2d 937, 1938 U.S. App. LEXIS 3369, Counsel Stack Legal Research, https://law.counselstack.com/opinion/johnson-laboratories-inc-v-meissner-mfg-co-ca7-1938.