(concurring).
The opinion passes upon only claim 1 of the Hedenskoog Patent No. 1,714,310, and therefore leaves the other seven claims unassailed. Since, however, it tends to leave their status somewhat ambiguous and since I believe the patent to disclose invention over the earlier Winn patent, I think it desirable to indicate my views. While I am never confident I know that worthy artisan the “mechanic skilled in the art” well enough to speak for him, it does seem to me that Winn would have taught him little and, indeed, would have given him the wrong clues entirely. I expect that had he arrived at the Hedenskoog result, it would be more in consequence of his general skill, or knowledge of other devices — a railroad switch, say, or the tracks of a toy electric train — than from what Winn disclosed. Plaintiff sued only on claim 1 of the patent, for the obvious reason that it thought that was broad enough to furnish a basis for a claim of infringement by defendant’s device, which was like Winn’s. To my mind, even the language of that claim, read in the light of the specifications and the drawings, hardly justifies so broad an interpretation, and I should not consider it to read directly upon the Winn patent. It describes much more than Winn’s “vibratable bar that receives the impact of a rolling ball near one end” and retards the ball by being “cushioned at the opposite end by air pressure.” For it first describes a stop above the rails on which the returning ball travels and then it adds “a member below said stop and mounted for movement under the weight of the ball for releasing said ball from said stop and permitting the further movement of said ball.” (Emphasis added.) That seems to describe the device discussed below, not Winn’s single-arm cushioned retarder. Hence, for my part, I should have considered the preferable conclusion to be that, construed reasonably strictly according to its sense and intent, claim 1 was not invalid, but merely not infringed here.
Since, however, the broader interpretation is possible, and other claims are clearly limited so as to support a patent, I shall not press my view. But this makes more *73imperative a suggestion of the difference I find between the patent as thus claimed and the Winn patent. As indicated above, the latter shows only a single device, consisting of a retarder holding back the ball by reason of the pressure cushioned at its other end. Obviously the counterpressure at the end of the retarder must be exquisitely adjusted to the forward force exerted by the ball itself, or else it will not operate automatically and with precision. If the retarder does not hold well enough, the ball will crash through to land ultimately as chance and its force direct; if it holds too well, the ball will stop on the tracks. But since the pressure of the ball varies with its speed and weight, the counterpressure should vary at least with the strength of arm of the pin boy — which shows why this device has been found inoperable when tested. The Hedenskoog device, however, has two important parts. First is the stop above the rails which completely and automatically stops each ball. Then there is the device whereby the rails drop slightly, because of the zveight of the ball, and against the pressure of the dashpot below, to release the ball from the upper stop and allow it to roll to its place of rest, while the rails return to their position. This seems as ingenious as it was effective and automatic in practice; it appears to have taken thirty-five years for its development after Winn, with essentially nothing worth while in between; and it has therefore seemed an invention to the judges who have heretofore considered it. See the careful analysis of Judge Barnes in 43 U.S.P.Q. 10, and of Judge Clancy below, 60 U.S.P.Q. 295.1
The suggestion that invalidity must follow in consequence of a lack of specification of an adjustable exhaust port to the dashpot — based on the testimony of a witness for plaintiff separated from its context — seems to me unpersuasive. Thus singled out, the point assumes an importance which the obvious nature of the operation — surely within the ken of our skilled mechanic — hardly justifies. Changing air pressure by varying the size of an air opening is not novel; it was in fact completely illustrated in Winn. Further, the Hedenskoog device is shown to operate against a spring, with also the assistance of a fluid. Use of a spring, a fluid, the air, or some combination of them, to check the descent of the pivoted rails and to return them to position after the ball has rolled off, seems easily feasible; and clearly some adjustment of the parts to the operation required must be made initially and from time to time thereafter. Detailed specification of the obvious seems unnecessary. Invention is hardly to be based, or to depend, upon varying the size of a hole to let out air. Of course, the need of such adjustment is both much less and much less continuous than in the Winn device.
No opinion for publication.