Eagle Iron Works v. McLanahan Corporation

429 F.2d 1375, 166 U.S.P.Q. (BNA) 225, 1970 U.S. App. LEXIS 8241
CourtCourt of Appeals for the Third Circuit
DecidedJuly 9, 1970
Docket17925
StatusPublished
Cited by22 cases

This text of 429 F.2d 1375 (Eagle Iron Works v. McLanahan Corporation) is published on Counsel Stack Legal Research, covering Court of Appeals for the Third Circuit primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Eagle Iron Works v. McLanahan Corporation, 429 F.2d 1375, 166 U.S.P.Q. (BNA) 225, 1970 U.S. App. LEXIS 8241 (3d Cir. 1970).

Opinions

OPINION OF THE COURT

FORMAN, Circuit Judge.

This is an appeal by the McLanahan Corporation of Hollidaysburg, Pennsylvania, from a judgment of the United States District Court for the Western [1376]*1376District of Pennsylvania in favor of Eagle Iron Works [Eagle], a corporation of Des Moines, Iowa. The case involves a patent infringement suit instituted by Eagle against McLanahan under 28 U.S. C. §§ 1338(a) and 1400(b), alleging infringement of United States Letters Patent No. 3,160,321. McLanahan urges that the patent is invalid as obvious and that Eagle is estopped from claiming infringement because McLanahan acquired intervening rights as a result of a Certificate of Correction issued to Eagle and because of Eagle’s inequitable conduct before the Patent Office in securing the Certificate. The case was tried without a jury and the District Judge held that the patent was valid; that McLanahan had infringed claims 1, 2, 3, 15 and 16, and that Eagle was not estopped from claiming infringement.

The patent in question is known commercially as “AUTOSPEC.” It is an automated control system for a water scalping and sand classifying tank, a principal element in the apparatus of modern sand plants, which classifies sand and gravel by size and reblends them to given specifications. It was developed by Clement B. Cochran, an employee of Eagle, who began working on it in 1959. The first patent application was filed in 1961. Ultimately, the patent in suit, numbered 3,160,321, was issued on December 8, 1964 to Mr. Cochran, assignor to Eagle.1

In general, sand is classified by size by introducing a slurry mixture of sand and water into a water scalping and sand classifying tank. The tank is an elongated V-shaped rectangular receptacle which allows the slurry to flow longitudinally into it. The coarser sand settles first nearest the feed end and progressively finer sand settles toward the other end. This settling occurs as a result of two forces: (1) the velocity of the slurry stream; and (2) gravity. Slimes and extremely fine particles are discharged at an overflow weir at the end opposite the introduction point.

In a conventional tank reblending was accomplished by a series of discharge stations located along the bottom of the tank. Each station discharged a different size sand. Discharge occurred when a sand level sensing device, such as a paddle on a rotating shaft, usually 14 to 18 inches above the bottom of the tank, determined an adequate accumulation of sand. When this occurred, the station opened and the sand flowed into a splitter box. Each splitter box (one for every station) had two or more discharge gates connected to separate flumes. If two different specifications were desired, a three-gate splitter box was used, two gates for products and one for waste. Each gate of the box was manually adjusted to give the desired proportion. The two proportions representing products were then passed into [1377]*1377two separate flumes to form the two specification products. A typical arrangement was a three gate box where two gates were set for products, one cement and one concrete, and the third for waste. The structural and functional details of the operation of the conventional tank, as described above, were well known in the art at the time of the Cochran invention.

The primary problem with a conventional tank was that the size gradations fed into the tank could vary, creating a corresponding variation in the amounts available at each discharge station. This made it necessary to sample each product at frequent intervals to determine whether it was receiving a proper proportion of the various sizes of sand. If the proper proportion of one size was not being fed into the products, the gates had to be adjusted accordingly. Without constant sampling and readjusting, large build-ups of non-specification material resulted.

The Cochran invention eliminates the manual operation and the need for splitter boxes. It produces a continuous product despite changes in the input to the tank. To accomplish this, it employs a number of timers that measure the cumulative times of sand discharged from the individual outlets at the discharge stations. This cumulative timing mechanism is one of the essential features of the Cochran invention. Simply described, it is a system having three outlets with two discharge stations for products and one for waste, which operates as follows: When the predetermined amount of sand at any outlet is discharged, the timer “times out” and closes the valve. The excess material is diverted to either another product outlet at the discharge station or to a waste outlet. When all the outlets for a product “time out” the system resets itself.

Late in 1962, McLanahan, a competitor of Eagle in the manufacturing and sale of this type of machinery, undertook to develop an automatic system to control its sand classifying and water scalping tanks. Allegedly, this undertaking was totally independent of Eagle’s work.2 McLanahan solicited the aid of Jordan Controls, a supplier of electrical control apparatus. McLanahan submitted to Jordan a set of specifications of the type of system it desired together with drawings pursuant to which and under Mc-Lanahan’s direction Jordan designed a system which McLanahan incorporated in its tanks and sold under the name of “CARDO-MATIC.” One of its sales was to Fayettville Sand and Gravel Inc., in Fayettville, North Carolina in March 1965. It is this system that Eagle alleged, and the District Judge found, infringed the Cochran invention.

Practically all of the facts involved in this litigation were stipulated by the parties. There is little contest as to Mc-Lanahan’s infringement of the Cochran patent unless McLanahan prevails in its contention that the patent is void for obviousness, that the Certificate of Correction was invalidly issued or on its subsidiary assertions that it had intervening rights and that Eagle acted in bad faith in inducing the Patent Office to issue the Certificate of Correction.

Defense of Obviousness

McLanahan claims that the Cochran invention is invalid under 35 U.S.C. § 103 which states:

“A patent may not be obtained though the invention is not identically disclosed or described as set forth in section 102 of this title, if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the [1378]*1378time the invention was made to a person having ordinary skill in the art to which said subject matter pertains. Patentability shall not be negatived by the manner in which the invention was made.”

In Graham v. John Deere Co.,3 the Supreme Court outlined the applicable test in determining obviousness as follows:

“Under § 103, the scope and content of the prior art are to be determined, differences between the prior art and the claims at issue are to be ascertained; and the level of ordinary skill in the pertinent art resolved. Against this background, the obviousness or non-obviousness of the subject matter is determined.” 4

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Eagle Iron Works v. McLanahan Corporation
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Cite This Page — Counsel Stack

Bluebook (online)
429 F.2d 1375, 166 U.S.P.Q. (BNA) 225, 1970 U.S. App. LEXIS 8241, Counsel Stack Legal Research, https://law.counselstack.com/opinion/eagle-iron-works-v-mclanahan-corporation-ca3-1970.