Mott Corporation v. Sunflower Industries, Inc.

• Decision Date: 12 March 1963
• Docket Number: No. 6962.,6962.
• Citation: 314 F.2d 872
• Parties: MOTT CORPORATION and C. W. Mott Research Engineers, Appellants, v. SUNFLOWER INDUSTRIES, INC. and Owen Murrell Crump, Appellees.
• Court: U.S. Court of Appeals — Tenth Circuit

314 F.2d 872 (1963)

MOTT CORPORATION and C. W. Mott Research Engineers, Appellants, v. SUNFLOWER INDUSTRIES, INC. and Owen Murrell Crump, Appellees.

No. 6962.

United States Court of Appeals Tenth Circuit.

March 12, 1963.

COPYRIGHT MATERIAL OMITTED

George N. Hibben, Chicago, Ill. (Hibben, Noyes & Bicknell, Chicago, Ill., Thomas E. Scofield and Carter H. Kokjer, Kansas City, Mo., were with him on the brief), for appellants.

Claude A. Fishburn, Kansas City, Mo. (Orville O. Gold, Fishburn and Gold, Kansas City, Mo., and W. C. Jones, Olathe, Kan., were with him on the brief), for appellees.

Before BREITENSTEIN, HILL and SETH, Circuit Judges.

HILL, Circuit Judge.

Appellants brought this action in the court below against appellees for alleged infringement upon claims 6 to 13 of United States Patent No. 2,590,065 issued March 18, 1952, to the International Harvester Company and owned by the Mott Corporation. Appellants sought an injunction against further infringement, treble damages for past infringement, and attorney fees. Appellees' answer denied infringement and asserted the usual defenses of invalidity, lack of invention, aggregation and indefiniteness of the claims as well as misrepresentations by the patentee in the Patent Office.

The case was tried to the court and resulted in a judgment holding claims 6 to 10, inclusive, valid and infringed by appellees' accused machine, and claims 11 to 13, inclusive, invalid on the grounds of anticipation and lack of invention over the prior art. The defense of misrepresentation was denied.

This appeal is from that portion of the judgment holding claims 11 to 13 to be invalid. It is admitted that if such claims are valid, then they have been infringed by the accused machine. Therefore, the only question before us is the validity of claims 11 to 13.

The patent in suit, hereafter referred to as the Mott patent, is for a mowing machine which is sold commercially under the name of the Mott Hammer-Knife Mower. The application was filed originally on August 16, 1947, by Carl W. Mott, Sr., who, at that time, was an employee of International Harvester. In the specifications it is stated that "This invention concerns grass-cutting mowers of a type employing flails pivotally mounted on a carrier which is rotatable at high speed about a horizontal axis for sweeping cutting edges of the flails into the grass for cutting the same, and relates more particularly to an improved type of flail and mounting thereof." The specifications further state:

"The general object of this invention is the provision of an improved type of cutter flail or knife provided with a cutter end portion turned outwardly from a pivotally supported shank portion in a manner enabling the cutter portion to cut a miniature swath while accommodating centrifugal discharge of cut grass stems endwise from the flail."

The mower is sold in a number of sizes, ranging from smaller machines suitable for cutting lawns to larger machines used for highway maintenance, parks, golf courses and airports. Prior to the advent of the Mott mower, the sickle bar, reel and rotary types of mowers were used exclusively. Each of these mowers has certain objectionable features when operated under particular conditions and no one of them may be considered an all purpose mower.

The Mott mower was designed to alleviate many of the objectionable features of the other three types of mowing machines. It can be used in short or tall grass and weeds; it mows smoothly and evenly, laying the finely chopped clippings or shredded cuttings down in an even mulch on the ground without wind-rowing; and it does not throw rocks or other debris which might be struck by the mowing blades. The operator walks behind the smaller models of the Mott mower and the larger models are pulled or pushed by a tractor. The cutting device consists of a rapidly rotating shaft which is carried horizontal and parallel to the ground and on which are mounted a number of flails or knives. The knives are pivotally and loosely mounted on pins which are fastened to the shaft, which allows them to swing out or stand out radially by centrifugal force into the cutting position when the shaft is rotating. A roller and wheels support the shaft above the ground at whatever height is required to leave the uncut grass the desired length. The knives or blades are spaced around the shaft in a helical pattern, which causes an overlapping of the swaths cut by each blade. The name of the mower is apparently taken from the similarity between its action and that of a hammer-mill.

The claims in question¹ relate only to the knives or blades. The asserted inventive feature involved is the alleged self-cleaning capacity of the blades under all types of grass and moisture conditions. Each of the blades is about 5 inches long, ¾ of an inch wide and 1 1/6 of an inch thick. There are 120 blades on the rotatable shaft of a mower made to cut a four-foot swath. These blades are mounted in pairs and in four rows spaced circumferentially around the shaft with fifteen pairs of blades in each row. Each blade has a hole in one end for the pin by which it is attached to the shaft, and, at the opposite end, the blade is bent or curved. The bent or curved portion is about one inch long and is the cutting portion of the blade. The angle of the bend is claimed to be critical, i. e., if it is greater than approximately 65 degrees as measured between the blade tip and the plane of the shank portion, grass will collect on the bent portion and impair the cutting operation. The knives or blades are mounted or arranged in pairs back-to-back, which means that each pair of blades is mounted on a single pin, with the back of the shank of one blade abutting and in substantial engagement with the back of the shank of the other blade, so that the bent or curved cutting tips diverge away from each other in opposite directions.

The different views and forms of the blades are shown in the various drawings thereof contained in the patent file. The patent states that the angle of departure of the diverging end portion from the shank of the blade is sufficiently restricted to accommodate centrifugal discharge of the cut grass along the outwardly turned or bent portion and over the free end. It further states:

"* * * An angle a not substantially exceeding 65° is preferred for enabling the flail end portion to cut a reasonably wide swath while avoiding accumulation of grass stems upon such end portion. The end portion * * * illustrated in Fig. 1 has an angle of departure a of 66° which has been found in practice to give excellent results."

Other drawings of the blades as illustrated in the patent figures show an angle of departure of 39 degrees. The blades sold commercially by appellants over the years have had an angle of about 37 degrees. This lesser angle on the new blades is used because the cutting ends tend to bend upwardly upon striking obstructions thereby increasing the angle. When an angle of 65 degrees is reached, the blades should be replaced.

In support of their claimed inventive feature, i. e., the angle at which the cutting tips are bent to allow a self-cleaning effect, appellants introduced evidence at the trial in the form of exhibits to show: If the blades are at angles of 65 degrees or less, the centrifugal force at the blade tip is sufficient to overcome the resistance presented by the blade angle and all grass and clippings will be thrown from them; however, if the angle is more than about 65 degrees and the grass or weeds have high internal moisture content, the resistance to centrifugal force is greater and the cuttings will not be thrown from the blade. Thus, appellants' position is not that blades with an angle at their tip of more than 65 degrees will not mow at all, but that such blades will not mow efficiently under all moisture conditions and therefore could not be used on a successful commercial mower.

Since appellees have admitted that the accused machine infringes upon the claims in question, if valid, it is not necessary for our purposes to describe such machine. Suffice it to say the trial court found, and the evidence confirms, that the accused machine is a virtual "Chinese copy" of the Mott mower.

It is, however, in view of the question presented, necessary to discuss the prior art relied upon to show the invalidity of the claims in question. The prior art relating to the blade claims consists of the following: Herriot Patent, No. 356,602 (British), issued in 1931; Goeldner Patent, No. 1,258,109 (Germany), issued in 1918; and Wallace Patent, No. 1,051,933 (U.S.), issued in 1913. Other patents are cited in the file wrapper reference but they are not material to the issues here. It should be noted, however, that Wallace and Goeldner were not cited by the Patent Office.

Mott's patent application, with respect to the blades, was originally rejected by the Patent Office, primarily upon the basis of the disclosures made in Herriot. In reply to such action, Mott argued that Herriot disclosed only an angle of departure on the blade of about 70 degrees, which was 5 degrees greater than the maximum angle of 65 degrees recommended by him; that a blade with an angle such as shown in Herriot would not permit centrifugal shedding of folded over grass stems, especially when the grass was mature and limp because of moisture saturation; and that the Herriot device was not concerned with cutting lightweight, sparsely located particles, such as grass stems. The claims were again rejected with Herriot being the principal reference and it was said by the Patent Office: "To construct the cutter blade 1 of the Herriot et al. patent so that the cutter tip has a greater or lesser degree of departure from the blade portion, is held to be a matter of degree, within the scope of choice or design, not involving invention." Thereafter, a personal interview was had with the Patent Examiner, at which time a...