Eagle Iron Works v. McLanahan Corp.

303 F. Supp. 1029, 161 U.S.P.Q. (BNA) 421, 1969 U.S. Dist. LEXIS 13182
CourtDistrict Court, W.D. Pennsylvania
DecidedFebruary 5, 1969
DocketCiv. A. No. 66-3
StatusPublished
Cited by2 cases

This text of 303 F. Supp. 1029 (Eagle Iron Works v. McLanahan Corp.) is published on Counsel Stack Legal Research, covering District Court, W.D. Pennsylvania 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 Corp., 303 F. Supp. 1029, 161 U.S.P.Q. (BNA) 421, 1969 U.S. Dist. LEXIS 13182 (W.D. Pa. 1969).

Opinion

FINDINGS OF FACT, DISCUSSION, CONCLUSIONS OF LAW AND ORDER

JOHN L. MILLER, District Judge.

This action having been tried by the Court without a jury, the Court makes the following:

FINDINGS OF FACT1

The Parties and, Commencement of This Action

1. The Plaintiff, Eagle Iron Works, is an Iowa corporation having an office [1031]*1031and principal place of business at 129 Holcomb Avenue, Des Moines, Iowa (St. 1).

2. The Defendant, McLanahan Corporation, is a Pennsylvania corporation having an office and principal place of business in Hollidaysburg, Pennsylvania, within the Western District of Pennsylvania (St. 2).

3. Defendant, McLanahan Corporation, and Plaintiff, Eagle Iron Works, are and for a period of years have been engaged in direct competition in the manufacture and sale of sand classifying equipment (St. 4).

4. By letter dated January 8, 1965 (PX 43) delivered January 11, 1965, the Defendant, McLanahan Corporation, was charged by the Plaintiff, Eagle Iron Works, with infringement of claims 1, 2, 3, 15 and 16 of United States Letters Patent No. 3,160,321 (PX 1) issued to Eagle Iron Works on December 8, 1964, as assignee of the inventor, Mr. Clement B. Cochran (St. 5, 23). In these Findings, patent No. 3,160,321, the patent in suit, is referred to as the Cochran ’321 patent.

5. By letter dated July 21, 1965 (PX 70), and through subsequent conversations and correspondence, the charge of infringement was continually and consistently denied (St. 6).

6. On January 3, 1966, the present action for infringement of the Cochran ’321 patent was instituted by the Plaintiff, Eagle Iron Works, against the Defendant, McLanahan Corporation (St. 7). Trial was held February 5-12, 1968.

7. The apparatus accused of infringement has been assembled by the Defendant at its manufacturing facilities in Hollidaysburg, Pennsylvania, and has been sold by the Defendant, acting from its facilities in Hollidaysburg, Pennsylvania. (St. 8).

Water Scalping Sand Classifying Tanks in General

8. To achieve optimum strength and consistency, in concrete, controlled graduation of various sizes of sand and gravel particles is necessary in the aggregate employed in the concrete mix. Particle sizes for concrete sand are specified, in specifications developed by the American Society for Testing Materials and other agencies, in terms of percentages of material passing or retained on screens of given density. The specifications for concrete sand may be quite stringent. Similar specifications may be imposed for other sand products, particularly mason’s sand (St. 9; Thalacker Tr. 49-61; PX 48-50).

9. A water scalping sand classifying tank is a principal element in many modern sand plants. The scalping tank removes excess water from a slurry of sand and water, eliminates sand particles of unwanted sizes, classifies the sand by particle size, and reblends the sand in accordance with one or more specifications. (St. 10; Thalacker Tr. 48; PX 47).

10. In a water scalping sand classifying tank, size classification is achieved by differential settling of sand from a water-sand slurry. The slurry is introduced into one end of an elongated V-shaped generally rectangular tank, flowing longitudinally of the tank. The sand settles out along paths determined by (1) the velocity of the slurry stream moving through the tank, and (2) gravity. Because the sand particles are essentially uniform in specific gravity, settling is a function of particle size. Larger and heavier particles settle out first near the feed end of the tank. Progressively smaller particles settle out along the length of the tank. Slimes and extremely fine granular particles may be discharged at an overflow weir at the end of the tank opposite the slurry feed. (St. 11; Thalacker Tr. 61-62; PX 51).

11. A scalping tank has a plurality of discharge stations distributed longitudinally along the bottom of the tank; the number of stations may vary from five to twelve or even more. The discharge stations are located closer together adjacent the feed end of the tank than at the overflow end of the tank. Because of [1032]*1032the differential settling, in the tank, by particle size, each discharge station, when opened, discharges sand particles of a relatively consistent size range. (St. 12; Thalacker Tr. 63-65; PX 53, 65).

12. In normal operation of a water scalping sand classifying tank, discharge from a given discharge station occurs only when sufficient sand has accumulated at that station, so that the discharge is essentially wet sand with only a minimum of water. Each discharge station has a device to sense whether sufficient sand has accumulated at the station to allow effective discharge without “blowing” of excess water. (St. 13; Thalacker Tr. 66-67; PX53).

13. The most generally used sensing device comprises a paddle mounted on a rotating shaft, usually about 14 to 18 inches above the bottom of the tank. The paddle and shaft are driven by a torque motor mechanically connected to an electrical switch (PX 33). Sand settling in the tank bottom ultimately blocks rotation of the paddle. The reaction of the motor trips the switch and thus electrically actuates a mechanism to open the discharge valve. When enough sand has been discharged to release the paddle, the switch returns to its original position and the valve closes. Valve actuation is usually accomplished hydraulically but may be effected pneumatically or mechanically. (St. 14; Thalacker Tr. 66-67,83,96-97; PX53).

14. In conventional tanks, each discharge station has a single discharge valve opening into a splitter box (PX 34, PX 54). The splitter box has two, three, or more discharge gates connected to separate flumes. Thus, if two specification products and a waste product are to be produced, a three-gate splitter box is provided for each discharge station. The gates on the splitter box are manually adjusted so that different proportions of the sand from each station of the tank are passed on to two separate flumes for the two specification products and any excess goes to the waste product flume. (St. 15; Thalacker Tr. 67-71; PX 54).

15. The water scalping classifying tank does not make a precise separation of particle sizes on the same basis as a screen; it cannot be said that all eight-mesh material will settle out at the first discharge station and that all sixteen-mesh material will settle out at the second discharge station. But there is a distinct and measurable difference in the gradation of materials accumulated at the different discharge stations. Proper control of the re-blending of the materials from the different discharge stations makes it possible to meet ordinary specifications. The tank is especially advantageous in eliminating unwanted sizes and in preparing two or more specification materials simultaneously. (St. 16; PX 65-67).

16. The size gradation of materials fed to the classifying apparatus may vary to a substantial extent. These variations result in corresponding fluctuations in the amounts of sand available at each discharge station. With conventional splitter boxes employed to re-blend the sand in specification products, it is necessary to sample each product and to adjust the splitter gates to hold the size gradations relatively constant. Without constant sampling and supervision, the conventional tank can produce a build-up of non-specification materials in the stockpiles of the plant. (St.

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Bluebook (online)
303 F. Supp. 1029, 161 U.S.P.Q. (BNA) 421, 1969 U.S. Dist. LEXIS 13182, Counsel Stack Legal Research, https://law.counselstack.com/opinion/eagle-iron-works-v-mclanahan-corp-pawd-1969.