688 F.2d 1242 (9th Cir. 1982), 79-4544, Omark Industries, Inc. v. Textron, Inc.

Docket Nº:79-4544.
Citation:688 F.2d 1242
Party Name:216 U.S.P.Q. 749 OMARK INDUSTRIES, INC., Plaintiff-Appellee, v. TEXTRON, INC., Defendant-Appellant.
Case Date:September 27, 1982
Court:United States Courts of Appeals, Court of Appeals for the Ninth Circuit

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688 F.2d 1242 (9th Cir. 1982)

216 U.S.P.Q. 749

OMARK INDUSTRIES, INC., Plaintiff-Appellee,


TEXTRON, INC., Defendant-Appellant.

No. 79-4544.

United States Court of Appeals, Ninth Circuit

September 27, 1982

Argued and Submitted March 2, 1981.

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John M. Webb, Webb, Burden, Robinson & Webb, Pittsburgh, Pa., for defendant-appellant.

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Kenneth S. Klarquist, Klarquist, Sparkman, Campbell, Leigh, Hall & Winston, Portland, Or., for plaintiff-appellee.

Appeal from the United States District Court for the District of Oregon.

Before ANDERSON and CANBY, Circuit Judges, and CRAIG, [*] District Judge.

J. BLAINE ANDERSON, Circuit Judge:

Omark, as assignee of the Graversen patent (U.S. Patent No. 3,929,049), initiated this action against Textron alleging infringement of the assigned patent. Textron answered by denying infringement and counterclaimed alleging the invalidity of the patent. The parties stipulated to have the case tried before United States Magistrate George E. Juba. In a written opinion, which constituted the findings of fact and conclusions of law as required by Fed. R. Civ. P. 52(a), Magistrate Juba determined that claims 2 through 4 of the patent were valid and infringed. Thereupon, the district court, Judge Otto R. Skopil presiding, entered judgment enjoining Textron's infringement and finding that Omark was entitled to an accounting to determine its damages and its right to attorneys' fees and interest. Textron's counterclaim was dismissed. The injunction and accounting were stayed pending the outcome of this appeal. The district court had jurisdiction pursuant to 35 U.S.C. § 281 and 28 U.S.C. § 1338(a). The primary issues raised by Textron on appeal are whether the district court properly found the patent infringed and whether the district court erred in failing to find the patent invalid for obviousness. We affirm.


The subject matter of the patent in suit is a saw chain for use on power chain saws. Chain saws came into popular use in the late 1940's and early 1950's. In the early 1960's, consumer chain saws arrived on the market. These saws were more lightweight, less expensive, and of lower horsepower than the commercial saws of the day. It is the design of the chain for such a consumer saw that is the subject of this appeal.

A typical saw chain consists of drive links, cutting links and tie straps which hold the two links together. 1 The cutting link is the key link in the operation of a chain saw. It has a base portion which includes two rivet openings for connecting it to the adjoining drive links. The base rides on the chain saw bar. Extending upward from the base is a depth gauge portion and a cutting portion separated by a recess. The depth gauge portion precedes the cutting portion in its path through the wood. The depth gauge, as its name implies, controls the depth of the cut made by the chain.


A saw chain is identified primarily by its pitch. The pitch of the chain is the average distance between the centers of three successive rivet holes. The pitch of a particular

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link is the distance between the centers of the rivet openings in such a link. 2

The early saw chains had pitches of 5/8 inch and higher. The first consumer saws used chains with a pitch of 1/4 inch. This size chain was an efficient cutting device but, because of the number of links required, it was expensive to manufacture.

In 1972, the high cost of the 1/4 inch chain led Omark to begin the development of a less expensive chain for use on consumer chain saws. Graversen, who worked for Omark, ultimately applied his efforts in developing a 3/8 inch pitch chain which incorporated cutting links used on the 1/4 inch chain. The cutting link was redesigned with a longer base to maintain chain stability.

This chain also utilized what can be termed a guard portion on the drive links that extended upward to protect the depth gauge and lessen the danger of "kickback." Kickback is the tendency of chain saws to react violently upward if an object contacts the chain as it travels around the upper portion of the nose of the saw bar. The bar is the portion of the saw on which the chain rotates. Conventional saw chains typically had depth gauges with substantially straight leading edges. As the chain travels around the upper portion of the nose of the bar, the leading edge of the depth gauge can become exposed and hook on branches and other objects. Such hooking could then rapidly and powerfully force the bar of the saw up towards the operator. Numerous injuries have resulted from this phenomenon. Prior to the Graversen invention, the universally adopted method of minimizing kickback was the use of safety or guard links. These links were designed to protect the leading edge of the depth gauge as the cutting links travel around the nose of the bar. While these safety links helped lessen kickback, they did not prevent it. They also reduced the efficiency of the saw chain and increased costs.

With this in mind, Graversen then redesigned the depth gauge on his extended pitch chain. He removed the guard portion on the drive link and then reshaped the depth gauge by sloping it rearwardly from the base up to a point rear of the front rivet opening. Tests showed the chain to cut faster than the standard 1/4 inch chain. It also exhibited virtually no kickback. Marketing under the name "91" began in the fall of 1974.

Graversen first applied for a patent on the chain in September of 1973. This application contained six claims. Believing it to read on prior art, 35 U.S.C. § 102, the examiner rejected the initial application. Claims 1-5 were dropped, a new one, 7, was added, and Graversen sought reconsideration. In October, 1974, the examiner again rejected the claims. A new amendment was sought, but this was rejected for procedural reasons. The original application was then abandoned and a new application, Serial No. 565,150, was filed. This new application, containing four claims, was allowed and the patent issued on December 30, 1975. 3

Claim 1, an independent claim, describes a cutter link with a low profile (low cutter height relative to the length of the base portion), and a pivot point located at the most rearward part of the base portion. Claim 2 is dependent on claim 1 and describes a rearwardly sloping depth gauge extending from the base portion to a peak behind the center of the front rivet hole. Claim 3 is dependent on claims 1 and 2 and describes a cutting link with the cutting edge located to the rear of a vertical line bisecting the distance between the front and rear rivet holes. Claim 4 is independent. It incorporates features similar to the preceding claims. It calls for a sloping depth gauge with a peak rearward of the front rivet hole, a cutting link with an extended pitch relative to the pitch of the drive link, and a cutting edge rearward of

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the line bisecting the two cutting link rivet holes.

Appellant quickly recognized the utility of the Omark design. From the fall of 1974 to February 1978, Homelite and Terry, two Textron subsidiaries, purchased approximately 650,000 feet of the chain. In 1974, Textron began testing the Omark chain in the hope of developing its own extended pitch economy chain. Eventually, the accused chain, the Pro-Cut 375, was developed and marketed. 4

There is no dispute that most of the attributes of the patented device appear on the Pro-Cut 375. Both have an extended pitch, a low profile, a rearward sloping depth gauge with a peak located behind the center of the front rivet hole, and a cutting edge located behind a point bisecting the rivet holes. Two differences in dimension exist and these form much of the basis for Textron's appeal. First, the location of the pivot point is not at the most rearward place on the base of the cutting link as called for in claim 1. Second, the peak of the depth gauge is not located behind the front rivet hole opening as claim 4 seems to require.

Prior to trial, Omark filed a disclaimer of claim 1 in the Patent Office and thereby restricted its claim of infringement at trial to claims 2, 3, and 4. Apparently, the disclaimer was filed in the belief that claim 1 read on prior art. Claim 1 remains significant, however, because claims 2 and 3 are dependent on it.


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