1. We entirely agree with that part of the judgment of the trial court which holds that the contract provision by which Seott agreed that he would not, during the life of the agreement, engage in the manufacture of any band-fastening device other than that covered by the field of invention described in the Seott patent is void, as against public policy. It is well settled that such contracts are void unless limited, as to time, space, and extent of trade, to what is reasonable under the circumstances of the case, because they tend to deprive the public of the services of persons in those capacities in which they are most useful, and also tend to expose the public tb the evils of monopoly. Richards v. Am. D. & S. Co. 87 Wis. 503. The restriction in the present case is an unlimited one as to space, and covers all states and countries. Berlin M. Works v. Perry, 71 Wis. 495. Even in cases where an established business is sold, and the vendor agrees not to engage in such business in the future, such agreement is only valid if confined to such limited time, and within such limited territory, as is reasonably necessary to protect the purchaser in the full enjoyment of the benefits of his purchase. Palmer v. Toms, 96 Wis. 367. In no view that we have been able to take of the case does the agreement before us, being unlimited as to territory, seem to be reasonable. Gamewell F. A. T. Co. v. Crane, 160 Mass. 50; S. C. 22 L. R. A. 673.
2. We are unable, however, to agree with the conclusion of the trial court to the effect that Seott violated his agreement or invaded any right of Teektonius, by manufacturing the band fastener which forms the subject of this action. Seott sold his patent of 1888 to Teektonius, but took back a contract giving him a right to manufacture and sell the invention described in it from a single shop in Racine. He then proceeded -to manufacture a band fastener identical in shape, construction, and principle with the band fastener which Teektonius had previously manufactured, and which *450bad been the subject of the previous litigation in the United States court. The result of this litigation is, of course, binding and conclusive upon both parties. In that litigation it was decided that the band fastener in question, which was then being made by TecMonius, was an infringement upon ■Scott’s patent. This might be so held without necessarily determining that Scott could manufacture it under his patent. Thus, if the Scott patent simply covered the grip feature, and the TecMonius device embodied this in combination with some other new and patentable feature, it might, perhaps, be that a simple judgment of infringement should be construed as deciding only that TecMonius infringed by incorporating the “ grip ” feature, and that hence the judgment was not a decision that Scott could manufacture the TecMonius device under his patent. But the judgment must be construed in the light of the written opinion of the judge.
It is a well-settled principle of patent law that, where a valid patent has been obtained, any improved machine which performs the same functions by equivalent means is an infringement. ITall, Patent Infringement, §§ 162-186. Also, that where an investigation of the state of the art shows that a given patented invention is of a primary character, and the patentee is a pioneer in the field, a larger latitude is given to the doctrine of equivalents than if the art has been well explored, and a change of form or combination only is involved. Id. §§ 155, 156, 199, 201.
While, as an original proposition, it must be doubted whether the TecMonius device was an equivalent of the device named in the Scott patent, still, if Judge SeamaN so decided, it is conclusive on the parties here. Did he so decide ?
Perusal of the opinion shows that he first considered the state of the art, and concluded that Scott was a pioneer in the art; that his invention was a distinct advance, entitled to fair, if not liberal, construction. Having so' held, he *451further held that, though the claims of the patent were not stated with clearness and breadth, still that “ a plain equivalent, performing the same function in the combination, is covered by the patent. So construed, it is clear that the defendant's device is a mere colorable deviation.” Here he evidently referred to the whole Teehtonius device. He calls it a “mere colorable deviation,” which is a smaller and more restricted term than an equivalent; the term equivalent being evidently nsed by him in its technical patent law sense. It seems certain that he held the Teelctonius device to be an equivalent. This construction of Judge Seaman’s judgment really ends the case upon this branch. The defendant, Seott, has an unquestioned right, under his contract, to manufacture the device that was covered and described by the patent of 1888; and, if he has the right to manufacture that device, he has the right to manufacture its 'legal equivalent, because that, also, is covered by the patent.
By the Court.— That part of the judgment appealed from by the plaintiff is affirmed, and that part of the judgment appealed from by the defendant is reversed, with costs, and the action is remanded with directions to render judgment for the defendant in accordance with this opinion.