American Phenolic Corp. v. Pollard

122 F. Supp. 172, 101 U.S.P.Q. (BNA) 480, 1954 U.S. Dist. LEXIS 3162
CourtDistrict Court, D. Maryland
DecidedJune 15, 1954
DocketCiv. A. No. 6377
StatusPublished
Cited by1 cases

This text of 122 F. Supp. 172 (American Phenolic Corp. v. Pollard) is published on Counsel Stack Legal Research, covering District Court, D. Maryland primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
American Phenolic Corp. v. Pollard, 122 F. Supp. 172, 101 U.S.P.Q. (BNA) 480, 1954 U.S. Dist. LEXIS 3162 (D. Md. 1954).

Opinion

COLEMAN, Chief Judge.

This is a patent infringement case involving patent No. 2,543,696, for high frequency transmission cable, issued February 27, 1951, to the plaintiff, the American Phenolic Corporation, as assignee of R. J. Krueger, inventor.

The plaintiff is an Illinois corporation with principal place of business in Chicago, and manufactures high frequency transmission cable for use in television installations. One of the defendants, the Plastoid Corporation, is a New York corporation engaged in the same manufacturing, and has sold to the other defendant, Charles R. Pollard, Jr., doing business under the name of Lytron Distribuí[173]*173ing Company, in Baltimore, as a dealer in television supplies, its cable which the plaintiff corporation claims infringes the Krueger patent.

Defendants deny infringement and also by way of defense assert invalidity of the Krueger patent which embodies 11 claims, but only 7 are in suit, namely, Nos. 1, 3, 4, 5, 9, 10 and 11. Claim 1 is the broadest. It is typical of claims 4 and 5, and reads as follows: “1. A cable for the transmission of relatively high frequency electric currents which comprises an elongated hollow tube constructed of a dielectric material, the walls of the tube being relatively thin compared to the tube diameter, and a plurality of electric conductors imbedded in opposite walls of the tube, said conductors being substantially coextensive with the length of said tube.” The Krueger cable is used for connecting the antenna and the television set, in order to carry or lead-in the television signal energy, and is thus described in the introduction to the specifications of the patent: “This invention relates to improvements in multiple-lead transmission cables and refers particularly to a cable of this class wherein the field between the leads is largely air, the cable being so constructed that moisture, water, ice or other substance detrimental to the efficiency of the cable as a transmission agency can never lodge between the leads constituting the cable.

“Multiple-lead cables for transmission purposes have heretofore been proposed, but substantially all have been characterized by having the leads separated by an excessive amount of solid dielectric material and the forms of said cables have frequently been such that when exposed to weather conditions moisture, water, ice, snow or other ‘high loss’ materials could lodge on the surface of the dielectric material separating the leads and within the electric field. In view of the fact that the field between such leads is most intense directly between the leads or conductors, the interpositioning in the field of the conductors of such "high loss’ material or materials not approaching the dielectric characteristics of air results in low transmission efficiency.

“As a feature of the present invention, the leads or conductors of the cable are embedded in diametrically opposite walls of a tube of dielectric material. The dielectric material employed is sufficiently stiff to prevent collapsing of the tube in normal use and is preferably a material which is weather-resistant and has per se good dielectric properties. By virtue of the position of the conductors in the tube walls, they will always be spaced a relatively constant distance from each other and the space between them is largely constituted of air being included between and shielded by the curved tube walls which are bisected by a plane disposed at right-angles to the plane of the conductor centerlines.”

As developed at the hearing, the antenna which picks up the television signal energy from broadcasting stations is usually located on the roof of the building in which the television set is located. The lead-in cable from the antenna to the set must have a pair of parallel conductors or wires, insulated one from the other, but mechanically held at a constant distance apart. In the early stages of the television industry a so-called flat, twin-lead or flat-line cable was commonly used, consisting of a pair of wires separated by a thin solid web of plastic, known as polyethylene. As long as such lead-in remained clean and dry, it performed satisfactorily. It was also found highly desirable that the lead-in cable be very flexible, in order to permit it being passed over eaves and through windows, as well as light in weight, in order to permit it being readily carried up ladders and on roofs, and, at the same time, it was necessary that it be strong enough to withstand inclement weather, involving wind and ice.

The flat twin-lead cable did not prove satisfactory for outdoor installation in many areas because, after a period of weathering, it became covered with deposits of foreign matter, the character of which varied with the location. For [174]*174example, along the seaboard, salt and moisture would accumulate, and in inland areas or where coal and oil were used extensively for heating, there would be deposits of soot, sulphur and various chemicals. Thus, this foreign matter, lying on the surface of the plastic cable between the two wires, greatly reduced the cable’s effectiveness and often resulted in poor reception, especially in locations a considerable distance from the broadcasting stations. As a result, during the years 1946, 1947 and 1948, when there was a great expansion in the production and sale of television sets, and a great advance in the scientific development of them, the problem of how best to overcome the effect, as above explained, of the elements on lead-in cables became an important one to the industry.

Krueger claims to have solved the problem when in 1948, he conceived the idea embodied in his patent whereby a pair of wires are embedded in the opposite walls of a plastic tube, which is thin, yet of such thickness as will enable it to receive the wires and to have the necessary strength to hold its tubular shape when bent. The wires can be easily pulled away from the tube by skinning off a bit of the plastic from the outside of the tube, while the plastic inner walls remain unbroken after removal of the wires. Krueger also taught two methods for sealing off the top of the tube, one consisting of heating the end of the tube with, for example, a match, and squeezing the sides together so as to let them seal as they cool; and the other method consisting of the insertion of a plug in the end of the tube after the wires have been pulled back, and then making the plug firm by heat or cement.

The most significant feature of the Krueger tube is the provision of an air space directly between the two wires. As stated by Krueger in his patent, “It is well known that in the transmission of high frequency electric currents the electric field directly between the conductors is strongest and depending upon the dielectric [non-conducting] material in said field greater or lesser ‘dielectric losses’ will occur. It is also known that air is an excellent dielectric. In the present invention, it can be readily seen that the major portion of the field between the opposite leads comprises air”. In addition, as Krueger explains, by reason of the tubular shape of the cable, “any foreign particles such as moisture, water, snow, ice, atmospheric dirt or the like which may deposit on the outer walls of the tube will be prevented from assuming a position between the conductors”. Also, the Krueger cable is strong, light, flexible and affords easy access to the conductors or lead-in wires.

Infringement

Turning first to the question of infringement, it is immediately apparent, by comparing the Plastoid cable with the Krueger cable, that the two are substantially identical in construction.

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122 F. Supp. 172, 101 U.S.P.Q. (BNA) 480, 1954 U.S. Dist. LEXIS 3162, Counsel Stack Legal Research, https://law.counselstack.com/opinion/american-phenolic-corp-v-pollard-mdd-1954.