PRATT & WHITNEY CO. v. UNION TWIST DRILL CO., 204 F. 447

BROWN, District Judge. This is -an appeal from a decree of the District Court dismissing a bill brought by the appellant, alleging infringement of letters patent to Hanson, No. 703,577, July 1, 1902, for “milling cutter.” For a description of the invention, and a statement of the principal questions, we may refer to the opinion of the District Court.

Only claim 1 of the patent is in issue : “A contour-milling cutter having one or more teeth of the full contour to be cut, and having some of the remaining teeth relieved below the contour at different portions of such succeeding teeth.” The specification states: . “As hitherto made the teeth of such cutters are all of the full desired contour, as represented by the tooth IS of Fig. 6.” In order to permit the ready access of oil to the cutting edges of the tool, and to permit the chips to roll up more freely, Hanson sought to improve the old type of milling cutter by cutting away portions of the teeth.

Teeth so cut he calls “relieved.” The District Court correctly held that, in view of the prior Lutz & Reiss patent, No. 93,212, Hanson was not entitled to cover broadly this feature. Each tooth of the Lutz & Reiss cutter is notched, or “relieved,” if we use that term broadly, and apparently enough of every tooth remains to serve for the application of a gage if that were desired. This is true, also, of all the teeth of defendant’s cutter, every one of which has some portion of its cutting edge removed or relieved.

One of these teeth, however, retains more of the cutting edge than others, and is doubtless specially designed to perform the function of a “gage tooth.” According to the testimony, this one tooth, which is cut away but partially on one side, is slightly more convenient for gaging than the other teeth, which are partly cut away on both sides, but which still retain enough for gaging purposes. Except for this one tooth, .specially designed for gaging, there could be no contention that claim 1 is infringed by the defendant’s cutter.

Bearing in mind that both the complainant and defendant are entitled to improve upon the full contour cutter of the prior art by providing notches in the cutters, it follows that invention must be found, if at all, in specific applications of this idea. Hanson’s cutter teeth were relieved or cut away in a special manner. Except the tooth of full contour, which had cutting edges on both sides as well as at the top, the teeth were staggered; i. e., the alternative sides of successive teeth were completely relieved, so as to have no cutting edge.

This arrangement is described in claim 2, which is not in suit, as follows: “2.

A thread-milling cutter, provided with closely adjacent integral teeth, having the contour of a truncated Y, the succeeding teeth being relieved slightly below the cutting-contour on alternately opposite sides, whereby the chips are cleared out of the cut by each tooth while providing for the flow of oil directly to the cutting edges of the succeeding teeth.” The full contour to be cut “is complete in any two adjacent teeth”; but, because one tooth is not opposite the other, it is impractical to apply a gage to determine the full contour.

This disadvantage of the staggered tooth arrangement in respect to gaging led to the retention of one tooth of old form. This one tooth enabled the cutter to be gaged in the same manner that full contour cutters of the prior art could be gaged — by applying a gage to a single tooth. In the complainant’s milling cutter we have, therefore, the combination of a gage tooth with other teeth, which are not gage teeth because staggered, and not in contact with both sides of the contour to be cut.

In claim 1, however, the teeth other than the gage teeth are described in very indefinite terms: “Sonic of tiie remaining teeth relieved below the contour at different portions of succeeding teeth.” The “relieved” teeth shown in the patent are cut completely away on one side. The defendant’s teeth are not cut completely away on either side. They are partly “relieved” on each side, except the gage tooth, which is partly relieved on one side only, and unrelieved on the other side.

The District Court held that the expression, “one or more teeth of the full contour to be cut,” meant that no portion of the cutting edg'e of these teeth was cut away or relieved.

The appellant contends that this was error, for the reason that one function of such a tooth “of the full contour to be. cut” is to furnish a “gage tooth” to serve as a gage or guide in regrinding the cutler, and that a tooth might still perform this function, though a portion of its cutting edge were removed or “relieved.” It is contended that it is not necessary that the edges of the tooth be continuous, provided that they be of sufficient extent to support the gage when applied, and to clearly indicate whether or not the teeth have been ground to correct shape.

But there is a difficulty in applying this argument consistently. Claim 1 is for a milling cutter having two kinds of teeth — full contour teeth and relieved teeth. If we interpret the term “full contour” to include a relieved tooth, and if a relieved tooth is of full contour if capable of being gaged, then by such

interpretation we have destroyed the only distinction made by the claim between the two kinds of teeth. The claim, then,- instead of being limited to a combination of gage teeth and teeth which are not gage teeth, covers a cutter in which all teeth are gage teeth. In other words, the claim then is broad enough to cover any cutter having nicked teeth that can be gaged. This is not merely a verbal difficulty, arising from the

interpretations placed upon the language of the claim. The difficulty is more substantial. The teeth of the cutters of the prior art were all capable of being gaged, since they were of full contour. It is proven that teeth may be relieved, so as to permit the flow of oil and permit the chips to roll up, without destroying the capacity of the teeth to be gaged. It was old to insert notches in the teeth of cutters for this purpose. Since Hanson adopted the staggered teeth, relieved entirely upon one side, such teeth did not possess the advantage of the teeth of the prior art in respect to gaging.

It was from this special mode of relieving teeth that arose the practical necessity for a gage tooth. Other applications of this general idea of relieving ,a tooth did not destroy the capacity for gaging, which was a feature of teeth of full contour, and also of teeth which, though nicked or grooved, retained enough of the lines of a full contour to permit gaging. The defendant’s device has teeth which may be said to be staggered at the upper cutting ends; but all teeth preserve enough of the lines of the full contour to permit the application of a gage to any tooth.

It may be said that all of the teeth are gage teeth, although one is a slightly better gage tooth than the others. There.is not, however, in defendant’s device the combination of teeth, incapable of gaging, with a gage tooth. We are of the opinion that claim 1, if given the

interpretation which complainant would have us place upon it, is practically meaningless in its failure to distinguish between the two kinds of teeth; and, if restricted to teeth relieved in the specific manner described in the specification and in claim 2, is not infringed.

Complainant’s argument that the gage tooth of the defendant is substantially the equivalent in function of the gage tooth of complainant, and that infringement cannot be avoided merely by evading the letter of a claim, provided the means are substantially equivalent, would be a sound argument in many cases; but in this case the fact that all the other relieved teeth of the defendant are substantially equivalent to the complainant’s single gage tooth, and possess a feature which was common to milling cutters of the older type and not new with Hanson, deprives this argument of force as applied to this particular case.

In construing the claim as a whole, it is evident that the patentee intended to make a distinction between teeth of full contoür and teeth relieved below the contour. An

interpretation which destroys this distinction is not permissible, since the claim then becomes meaningless. We are, therefore, of the opinion that the District Court was justified in giving the words, “of full contour to be cut,” their ordinary meaning, which, as is pointed out by the learned judge, accords with the language of the specification, “carrying the full contour; that is to say, to leave one tooth entirely unrelieved, like that of Fig. 6.” The decree of the District Court is affirmed, and the appellee recovers costs in this court.