which goes beyond the illustrative paragraph in Walker on Patents (2d Ed. § 350), as follows:
“But where a patentee states in his specification that a particular part of his invention is to be constructed of a particular material, and states or implies that he does not contemplate any other material as being suitable for the purpose, it is not certain that any other material will be treated by a court as an equivalent of the one recommended in tbe patent.”
However this may he, Winans v. Denmead leaves sufficient room for the application to the case at bar of tbe general rules of construction, and those relating to equivalents, which we have stated.
Some of the most important inventions in special arts have come from persons unskilled in those arts, and who, therefore, had no knowledge of the possible equivalents; so that it would involve improbability to assume that they had present in their own minds, at the time of the application, any matters of form except those incorporated in it. The rules cited from Winans v. Denmead, ubi supra, are needed to protect not only this class, hut all others who have made valuable inventions, and who, through their own ignorance, or for any other reason, have not understood, or have overlooked, possible equivalents. Without attempting the unnecessary discussion of case by case, it is enough that almost every patent in which this question can arise lies between the expressions in Winans v. Denmead, ubi supra, on the one hand, and those relied on by the defense on the other. Winans v. Denmead clearly goes as far in its direction as the case at bar. Applying the principles of construction and the law of equivalents already stated in the way in which we are hound to apply them, there is not sufficient in any or all of the expressions in the patent at bar relied on by the defense to justify us in holding that they amount to such a positive exclusion, arising either from the nature of tbe invention or from the necessary force of the words themselves, as will defeat a charge of infringement of all the claims in controversy, merely on account of a change in the method of producing relative movements of the parts, involving in itself no invention a,nd producing no result essentially new.
Some of the cases relied on by the defense strengthen these conclusions by the reflex light of the distinctions they make. Snow v. Railway Co., 121 U. S. 617, 7 Sup. Ct. 1343, held the patentee strictly to the details of Ms combination in question, because, as shown on page 630,121 U. S., and page 1343, 7 Sup. Ct., those details, for the reasons there stated, were essential parts. Sargent v. Lock Co., 114 U. S. 63, 5 Sup. Ct 1021, runs back, so far as this point is concerned, to Water-Meter Co. v. Desper, 101 U. S. 332; and so, also, does Fay v. Cordesman, 109 U. S. 408, 3 Sup. Ct 236, already cited. In Water-Meter Co. v. Desper, page 336, the court stated, touching a certain crank shaft which was in question, that it could not say that it was an immaterial part of the combination, and continued:
“The patent, as it stands, occupies very narrow ground. It requires the presence of every one of the elements specified in the combination secured by it.”
On page 335 this rule of interpretation is applied generally to combinations, and in this form the rule is traced through to the latest