Continental Oil Co. v. Cole

• Decision Date: 12 January 1981
• Docket Number: No. 78-1961,78-1961
• Citation: Continental Oil Co. v. Cole, 634 F.2d 188 (5th Cir. 1981)
• Parties: CONTINENTAL OIL COMPANY, Plaintiff-Appellant, Cross-Appellee, v. Jimmy R. COLE, d/b/a Jim R. Cole & Associates and Cole Development Co. Inc., Defendants-Appellees, Cross-Appellants.
• Court: U.S. Court of Appeals — Fifth Circuit

Page 188

634 F.2d 188

209 U.S.P.Q. 361

CONTINENTAL OIL COMPANY, Plaintiff-Appellant, Cross-Appellee, v. Jimmy R. COLE, d/b/a Jim R. Cole & Associates and Cole Development Co. Inc., Defendants-Appellees Cross-Appellants.

No. 78-1961.

United States Court of Appeals Fifth Circuit.

Jan. 12, 1981.

Rehearing and Rehearing En Banc Denied Feb. 12, 1981.

C. Frederick Levdig, John W. Kozak, H. Michael Hartmann, Chicago, Ill., Frank B. Pugsley, G. Bryon Jamison, Houston, Tex., for plaintiff-appellant, cross-appellee.

Pravel, Wilson & Gambrell, Albert B. Kimball, Jr., B. R. Pravel, Houston, Tex., for defendants-appellees, cross-appellants.

Appeals from the United States District Court for the Southern District of Texas.

Before RUBIN and POLITZ, Circuit Judges, and SMITH ^*, United States District Judge.

POLITZ, Circuit Judge:

Continental Oil Company (Conoco) appeals the determination by the trial court that its patent for a seismic cable depth-controlling paravane is not infringed by a device patented by Jimmy R. Cole. Cole cross-appeals, challenging the validity of Conoco's patent. We disagree with the trial judge and conclude that Cole's device infringes, being equivalent in function and operation to Conoco's paravane. We also conclude that Conoco's patent is valid. We therefore reverse the decision of the trial judge, render judgment in favor of Conoco and remand for further proceedings.

The issues posited to us can be resolved by applying well-established principles which have been stated and re-stated and, in the main, need only be capsulated. The sine qua non of appellate review of patent litigation is the notion that validity and interpretation are legal questions based upon factual inquiries. When confronted with pure questions of law, we are free to examine the district judge's answers and correct any error or oversight. In contrast, factual questions resolved by the trial court warrant deference and reversal is mandated only if the findings are clearly erroneous. Fed.R.Civ.P. 52(a). Although infringement normally is a fact question, legal questions of construction can become so intertwined that the clearly erroneous standard of review applicable to a pure fact finding must yield. The appeal we now decide falls into this latter category.

One form of infringement occurs when an accused device incorporates a teaching literally read. An infringement also occurs when a device appropriates a prior invention by incorporating its innovative concept and, albeit with some modification and change, performs substantially the same function in substantially the same way to achieve substantially the same result. The "doctrine of equivalents" shields the inventor from such abuse.

The determination of equivalency involves an examination of the scope of prior art, the essence or "heart" of the invention disclosed and the step forward the invention offers. A pioneer or generic patent which opens a new path is entitled to broader protection than a patent which merely improves upon that which is already known. The ambit of equivalency is also limited by the claims as made, amended or surrendered in the process which make up the "file wrapper" and grounds the defense of "file wrapper estoppel."

These principles were essentially noted by us in our recent decision in Weidman Metal Masters v. Glass Master Corp., 623 F.2d 1024 (5th Cir. 1980), and cases cited therein, particularly Studiengesellschaft Kohle v. Eastman Kodak Co., 616 F.2d 1315 (5th Cir. 1980).

In the case sub judice we are not favored with "findings ... sufficiently detailed to give us a clear understanding of the analytical process by which ultimate findings were reached and to assure us that the trial court took care in ascertaining the facts." Golf City, Inc. v. Wilson Sporting Goods, Co., Inc., 555 F.2d 426, 433 (5th Cir. 1977). Instead, the trial court's findings are in the main conclusory. In this situation we routinely would remand for more specific findings. However, "(t)his failure is merely a hindrance and not a fatal error." Whitley v. Road Corp., 624 F.2d 698, 700 (5th Cir. 1980). "Where the evidence is such that without weighing the credibility of the witnesses there can be but one reasonable conclusion as to the result, the case can be taken from the factfinding body." Waldon, Inc. v. Alexander Manufacturing Company, 423 F.2d 91, 93 n.3 (5th Cir. 1970).

The record is replete with evidence fully establishing the pertinent facts as they relate to infringement and validity. In the interest of judicial and other economies we are constrained to make the required factual collation to which we apply the legal principles resolving this dispute.

The questions before the court concern the validity of Conoco's patent, U. S. Patent 3,375,800 (the '800 patent), and whether it is infringed by Cole's patent, U. S. Patent 3,931,608 (the '608 patent). ¹

A. Factual Background

The invention which has bred this litigation was birthed by the need to efficiently and economically locate structures beneath the ocean floor which are likely to contain oil and gas deposits. Seismic survey crews first conducted their tests on land, and later went offshore as the technology in this field advanced.

Whether on land or at sea, seismic surveys are made by electronically transmitting sound waves down into the subsurface where, on the rebound, the signals are received and recorded on surveyor's charts. The study of these charts by persons with knowledge of subterranean geological formations leads to educated adumbrations as to whether the area contains a structure which may accommodate commercial quantities of oil and gas.

In marine seismic surveying the return sound waves are received in the water above the ocean floor by instruments called hydrophones which are spaced along and are integral parts of a cable towed behind a survey boat. Maintaining these hydrophones at a constant depth while minimizing unwanted "noise" is essential to the accuracy of seismic readings. Prior to Conoco's paravane invention, depth was controlled primarily by attaching floats and weights to a neutrally bouyant cable. This equipment tended to create substantial noise which interfered with and distorted the return signals, markedly reducing the accuracy and usefulness of information generated. A further drawback inherent in displaying the cable by means of floats and weights, in order to maintain a constant depth, was the limitation in the area a crew could survey in a routine day. In sum, not only was the pre-paravane process slow, arduous and uncertain, but costly delays were frequently encountered.

The '800 patent claims a device co-invented by Cole while he worked for Conoco as an electrical engineer. The patent discloses a depth-sensing paravane (also called cable levelers, cable controllers or "birds") which can be attached at spaced intervals to a marine seismic cable. The paravanes take the cable to a pre-set depth and maintain that depth while the cable is under tow. The evidence is uncontroverted that the paravanes of the '800 patent were a significant step forward in the technology of marine seismography. The device not only affords precise depth control with a minimum of noise, but also greatly increases speed in use. One witness with forty years of experience in seismic surveying testified that before using the Conoco paravanes, his surveying capacity was limited to 500 miles during a two month period. With the use of Conoco's paravanes, however, this range increased to 2,000 miles. Several witnesses emphasized the improvement in the accuracy of the seismic readings resulting from the reduction in the noise previously associated with controlling the cable depth. Finally, acceptance within the seismic survey industry also reflects the value of this invention. Within a short time after the paravanes became available a majority of the marine crews throughout the world were using them, including the crews of some of the largest companies.

B. The Patents in Suit

In resolving the issue of the validity of the Conoco patent, and in conjunction with our review of the infringement issue, we must examine the physical function and operation of three paravanes and certain accompanying patent claims. The first, the '800 patent, was co-invented by Cole and Paul L. Buller while Cole was, as noted, employed by Conoco. The second, the '608 patent, was patented by Cole four years after he left his employment with Conoco and went into business for himself. The third paravane, relevant only insofar as it represents the state of the prior art against which the validity of the '800 patent is to be tested, is U. S. Patent 3,372,666 (the '666 patent or Baker patent) owned by Texas Instruments.

1. Conoco Patent

The Conoco patent teaches an axial bore traversing the center of the embodiment of the invention through which the seismic cable passes. In other words, the paravene is placed concentrically around the cable. Because of the cable's length, usually one to two miles, it inevitably twists and turns while under tow. To prevent this movement from spinning or flipping the paravanes, each paravane is affixed by a pair of bearings, fore and aft, which permits the cable to rotate freely. By connecting the inner race of one or both of the bearings to the cable, the paravane is prevented from moving lengthwise along the cable and thus maintains its proper spacing.

In the commercially preferred manifestation of Conoco's invention, the cable-receiving bore penetrates through the center of the paravane housing. The patent, however, also discloses alternative designs in which the bearings which form the bore for receiving the seismic cable are offset from, but parallel to, the length of the main paravane housing. The depth-sensing and regulating mechanism, several variations of which are embraced by the patent, can be interchanged in the various paravane designs.

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