This case alleges infringement of a patent for an invention, and the decree in the District Court was for the respondent. Thereupon the complainants appealed to us. The opinion of the learned judge of the District Court refers to the fact that there were 21 claims in all; the first 16 being for a method or process, and the last 5 for the product. The opinion also states that the complainant asked the court to consider only 8 of the process claims, Nos. 3 to- 6, 8, ,9, 11, and 12, and only 4 of the product claims, Nos. 17, 18, 19, and 21.
The alleged defenses are lack of invention, anticipation, invalidity because of the changes made in the application before issue of the patent, and noninfringement. We need not distinguish the defenses by taking them each up, separately and specifically, because the whole case turns mainly about a single major proposition.
The opinion of the learned judge of the District Court says that the introductory statements in the patentees’ specification are that the inventions relate to the manufacture of metal articles of all kinds, and consist of a novel method of fastening their component parts together by process of electric welding, and also of the new articles produced thereby. He also observes that the inventions are further said to afford a cheap and practical substitute for riveting.
The brief for the complainants, now the appellants, states substantially the complainants’ case, as follows:
“Harmalta’s invention of the patent in suit was a new departure in the art of electric welding, which art had been created by the inventions of Prof. Elihu Thomson, in 1886, shown and described in the Thomson patents, Nos. 847,110 and 817,141.
"These Thomson patents show and describe for the first time the process of electric welding, but disclose only how it may he applied to joining the butt ends of two metallic rods together by passing an electric current of low voltage and high amperage from one rod to the other. The invention was a valuable one and went into commercial use, where the process became known as ‘butt-welding.’ In this Thomson butt-welding process two metal rods arc held by large copper electrode clamps, which are respectively *434the terminals of the electric circuit. When the current is turned, on, it flows in its circuit through the electrode clamps and through the ends of the rods which protrude beyond the electrodes. As the rods are of smaller cross-section than the electrodes, they restrict the flow of the current to the smaller path which they afford, and they thereby concentrate the current and increase its heating effect.
“The resistance of the rods, together with the resistance at the joint between their abutting ends, increases the heating effect of the current so that the ends of the rods are highly heated by the current and become plastic. The resistance and resulting heat at the joint are comparatively great, because of the break in the continuity of the metallic circuits, and the consequent obstruction to the flow of the current.
“When the , ends have thus become plastic, the rods are pressed bodily toward one another, the metal spreads and unites, with the result that the ends of the rods are joined by a weld. At the point where the joint is, the extruded metal forms an annular ridge.
“The characteristics of this butt-welding process are that—
“(1) The current is concentrated by the rods themselves, the ends of which are being welded together.
“(2) The welding heat is caused by the resistance of the metal between the clamps and by the resistance of the joint at the ends of the rods.
“(3) The area of the weld is determined by the area of the work — i. e., the ends of the rods.
“(4) The metal is extruded around the joint.
“(5) As the rods are united, they approach one another bodily, so that allowance for this always must be made.
“The plaintiff was formed to develop this Thomson invention. It has been engaged in the business of making and leasing machines for performing this process of butt-welding. It has also granted licenses, as, for example, to the other complainant, the Universal Company, which had a license for spot-welding, in 1909, which refers to prior licenses for ‘spot-welding,’ granted in 1904.
“These Thomson patents protected this business, for they covered broadly the process and product of electric welding, as Thomson’s invention was a true pioneer invention, having created the art of electric welding.
“But the underlying Thomson patents disclose as his only specific application of his fundamental invention one which was of limited utility, namely, the electric welding of the butt ends of two rods. But until Harmatta’s invention, by which' for the first time in the art it was practical and feasible by the use of new principles of operation to unite two thin plane sheets of metal together by electric welding, at any spot or at several spots of their contacting surfaces, no practical application of Thomson’s invention of electric welding was made beyond that of the butt-welding originally disclosed by him in his patents of 1886, in spite of the efforts of himself and other inventors.”
In order to make clear the state of the art, it was necessary to explain, as we have just done, the primary inventions covered by the patents of Elihu Thomson of 1886. These constitute the foundation of the whole art of electric welding, and the patent now in suit, as other secondary patents to which we may now refer, must be regarded as developments or branches of Thomson’s original invention, and as merely subsidiary inventions or improvements. There have been other subsidiary inventions, as, for instance, the lap-roller process, invented also by Thomson, by which the method of uniting the overlapping edges of two sheets of metal by a lap-weld was devised, and by virtue of which some other secondary inventions were made practicable; all of which may be regarded as growing out of the inventions of 1886, but all of which were in different fields from the spot-welding invention now un*435der consideration, and were in no way subsidiary to it or incidental thereto, sc> that neither the one nor any of the others anticipated Harmatta’s invention or were infringed by it or infringed it. Although all growing out of the same root, they were independent branches. Consequently, we have only to consider further the following alleged defenses to the complainants’ bill, namely:
That there is no patentable invention in welding separated spots.
That appellants’ attempted distinctions are without basis.
That there was no distinction between roller electrodes covering the entire amount of the overlap, and Harmatta’s process.
That Thomson’s sheet patent, No. 496, 019, showed sheet metal united by soldering, and thus anticipated.
That it also showed electrodes having area less than the contacting area, as in Harmatta.
That the Thomson process is the same as Harmatta’s, the difference being in the amount of pressure and current only, and that generally there was no showing of invention by Harmatta’s patent.
That the appellee’s does not infringe,
And that Harmatta’s patent is invalid by reason of changes since the original application.
Returning to the defenses based on the roller electrode process, or other processes devised with reference to overlapping sheets, it is all too plain that neither in its practical operation nor in its result was there any resemblance to the spot-welding such as to require discussion. It is quite plain that the attempts in that direction were too experimental to form the basis of any sound defense; indeed, that defense, and the proposition of accomplishing the work by soldering were each in an art so remote as to require no attention beyond these brief references thereto. These observations apply to all those lines of defense which rest upon the attempt to< compare the size of contact spaces or areas mathematically, because the spot-welding has nothing in common with such attempts; and, furthermore, a study of all these special defenses going to the proposition that spot-welding, as shown by Harmatta, was in any way anticipated, falls to pieces, because there was nothing in them in-, dicating an element of commercial success, and in this art, which was special and practicable, the art for rapid and inexpensive or cheap product was the first element of success. It is enough to repeat what we have already said generally; that is, in all these defenses of anticipation there is nothing which includes practicable utility.
Apparently much reliance is placed upon the claim that the application for the patent, during the many years it was pending, had been essentially changed, and so lost its validity. It originally embraced, not only spot-welding, but line-welding, and line-welding was not abandoned until after the alleged infringers in this case had constructed the machine with which they were operating when the bill was filed. The patent was applied for on December 3, 1903, and was not issued until December 3, 1912; but the claim for spot-welding was always in the application. The alleged infringing machines were first constructed in 1908; in 1910 the application covered both spot-welding and line-welding. It was then amended by striking out all claims for line-welding; *436so, therefore, perhaps no profits can be recovered for anything done prior to the amendment, and it is a question to be considered whether or not an injunction can go against machines constructed before the amendment was made, or, if at all, then to what extent.
We have no.t been called upon to give consideration to any questions of this character, and the bill and briefs in support of the bill do not suggest any qualified decree in the matter whatever. The bill -must, of course, be sustained, in view of the propositions we have alre'ady announced ; and in view of the further proposition that the presumptions in favor of the patent are so far supported in this case by the insistency of the defense, and the comparatively enormous expense involved in maintaining it, we cannot question the present validity of the patent with reference to all propositions involved in the word “patentability.” Nevertheless, the case is not put in such form as to. enable us to go to a final judgment without further investigation. Indeed, it is not positively established what the proceedings of the respondents have been since the patent issued. The nearest that comes to it is the admissions of the treasurer of the Barney & Berry Skate Works, the nominal respondents in this case, that the respondents had been using an infringing machine “before February, 1913,” and “just before that time.” There was also testimony of a witness for the complainant that he had seen the alleged infringing machines in operation on- January 9, 1913, and that the ends of the electrodes on the machines were all about a quarter of an inch in diameter.
Under the circumstances, "we can only enter a qualified judgment.
The decree of the District Court appealed from is reversed, and the case is remanded to that court for further proceedings not inconsistent with the opinion passed down on this 5th day of October, 1915, and the appellants recover their costs of appeal.
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