Metal Cutting Tool Service v. National Tool Co.

103 F.2d 581, 41 U.S.P.Q. (BNA) 688, 1939 U.S. App. LEXIS 3621
CourtCourt of Appeals for the Sixth Circuit
DecidedMay 4, 1939
DocketNo. 7742
StatusPublished
Cited by5 cases

This text of 103 F.2d 581 (Metal Cutting Tool Service v. National Tool Co.) is published on Counsel Stack Legal Research, covering Court of Appeals for the Sixth Circuit primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Metal Cutting Tool Service v. National Tool Co., 103 F.2d 581, 41 U.S.P.Q. (BNA) 688, 1939 U.S. App. LEXIS 3621 (6th Cir. 1939).

Opinion

SIMONS, Circuit Judge.

The bill filed by the appellant charging infringement of patent No. 1,463,473 to Lapointe for a broaching tool was dismissed in the court below because of non-infringement. Decision in respect to certain assailed structures of the defendant was based upon a construction giving limited scope to the claims in suit, and in respect to another structure it was held that the appellant having induced its manufacture was not entitled to equitable relief.

A broaching tool or broach is used in cutting and shaping metal parts, and is generally provided with a plurality of teeth which pass over the work in succession, each tooth removing additional metal over that removed by the preceding tooth. It differs from a saw in that the work and tool are never fed' toward each other perpendicularly to the plane of movement, and in that the broaching operation is completed by a single, pass of the tool over the work in a fixed path parallel to the surface to be cut. Broach teeth are made of the width of the surface to be finished and can be designed to finish surfaces of any contour. In the case of internal broaches for finishing circular or square holes in metal, the cutting edges extend entirely around the tool, which is designed to the shape and size of the surface to be finished.

In conventional broaches of the prior art a number of teeth employed in the cutting operation are of progressively increasing height so that as the broach moves parallel to the surface to be cut each succeeding tooth removes an additional layer of material. The remaining teeth of the broach are of equal height and are called finishing teeth. Of these only the first will perform any substantial cutting,' the rest of them performing only a smoothing or burnishing operation. All of the teeth in this type of broach have a top clearance or rake, that is, the top surfaces slope rearwardly from the cutting edge, the conventional clearance ' angle being from one and one-half to three degrees. It is without dispute that tee'th without such clearance will not cut. After a broach of this type has been dulled by use it is sharpened by grinding back the forward face of each tooth. This grinding reduces the height of the tooth because of the rake. When the last cutting tooth has been sharpened it will no longer cut to size, but since a plurality of finishing teeth are provided, and all are sharpened at the same time, the next succeeding tooth becames a cutting tooth, and this operation is repeated until the final tooth on the broach becomes dull, when the tool is no longer useful to cut to size. While in surface work a broach with teeth reduced by such successive sharpenings may still be used, there will be required a precise adjustment of the broach to the work, which greatly reduces the value of this type of broach for surface work.

The objective of the Lapointe invention was to prolong the life of broaches by providing a tool that could be more often sharpened than those of the prior art without becoming reduced in size. The invention involved a change in the shape of the top of the finishing teeth, and is said to be based upon the discovery that teeth which perform no cutting need not be' provided with rake or clearance entirely across the top of the tooth, since such teeth merely follow through, so Lapointe provided flat lands of substantial width extending rearwardly from the cutting edge and parallel to the direction of movement of the broach. These permit a sharpening of the finishing teeth by grinding away their front faces without a consequent reduction in size or height until they become successively cutting teeth arid permit repeated sharpening of all of the teeth at the same time. So the period of usefulness for a broach with teeth having flat lands was greatly increased over broaches of the prior art. [583]*583The Lapointe broaches have come into wide commercial use, and it is said in the record without contradiction that approximately 90% of the broaches now in use embody the features shown in the patent, and that the invention has increased the working life of a broaching tool from four to eight times that of broaches made prior thereto.

Lapointe was allowed four claims, of which three are printed in the margin.1 The only recorded prior art advanced by the defendant is a patent to Heinkel, No. 1,287,686, and a publication in the Machinery Handbook of 1915. The court below found no anticipation in either disclosure, and we agree. The Heinkel tool is one rotatably driven like a reamer, whereby the same cutting edge makes repeated cuts in the work, and it has no finishing teeth or any teeth of the same size or diameter. Nor is there any suggestion therein of lands of varying width upon teeth the sharpening of which will not reduce the diameter of the tool. The Machinery Handbook article describes no tool with teeth upon which lands are left after the hardening process or after the backing off of their tops.

It is urged, however, that since *in the course of manufacture of prior art broaches lands are provided upon the teeth, and since in order to make them operative and useful they are then backed off or relieved, thereby providing an operative and useful tool capable of cutting metal, so if during manufacture the first of the series is backed off the basic feature of the patent in suit is then produced, and the patent therefore merely appropriates this old unfinished device of the prior art as a new and complete article. Insofar as this contention suggests the application of the principle that one who but finds a new use for an old article may not thereon secure a valid patent, Weir Frog Co. v. Porter, 6 Cir., 206 F. 670; Grand Rapids Refrigerator Co. v. Stevens, 6 Cir., 27 F.2d 243; Page Steel & Wire Co. v. Smith Bros. Hardware Co., 6 Cir., 64 F.2d 512, it is sufficient answer to say that there is no evidence in the record that such partly finished broach was ever put to use, and the controlling principle is that novelty is not negatived by any prior accidental occurrence or production the character and function of which was not recognized until later than the date of the patented invention. 1 Walker, 6th Ed. 130, and cases there cited.

We think Lapointe made a useful and important improvement in broaching tools for accurate and economical machining of metal parts; that what he did was an exercise of the inventive faculty rather than mere mechanical .skill; that he is entitled to the inventor’s reward, and the claims of his patent are valid.

Of the broaches charged to infringe, some were surface broaches and others internal broaches. The three accused surface broaches are provided with a plurality of finishing teeth of uniform size which have lands of varying width and of progressively increasing width. Each of them falls within the terms of claims 1 and 2 of the patent. The trial court found that they do not constitute infringement because the invention has no utility when applied to a flat or surface broach and must therefore be limited to internal broaches, We think this was error. While the specification and drawings of the patent describe and depict internal broaches of cylindrical form, the claims are not limited to this type, and the record fairly establishes the utility of a surface broach responding to the teachings of the patent, even though their greater contribution is in the field of internal broaches.

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Bluebook (online)
103 F.2d 581, 41 U.S.P.Q. (BNA) 688, 1939 U.S. App. LEXIS 3621, Counsel Stack Legal Research, https://law.counselstack.com/opinion/metal-cutting-tool-service-v-national-tool-co-ca6-1939.