fringement and an accounting for profits and damages.
The district court held that the patent was valid, that the device of appellant infringed the palent, and granted an injunction against further infringements although finding that an accounting was not necessary. Appellant appeals from this judgment of the district court.
At no point in the proceedings in the district court or in this court was the validity of the patent seriously challenged. The material and decisive question presented and argued before, this court is whether appellant’s device infringed appellee’s patent.
Appellee relies upon Ralph N. Brodie Co. v. Hydraulic Press Mfg. Co., 9 Cir., 151 F.2d 91, 95, and urges upon us the rule there expressed that questions of infringement are questions of fact, and therefore in accordance with the Federal Rules of Civil Procedure, Rule 52(a), 28 U.S.C.A. following section 723c, this court will not set aside the determination of the trial court unless it is “clearly erroneous.” However, an examination of the Brodie case and the cases therein cited discloses that Judge Mathews made an application in the Brodie case of the correct rule earlier enunciated in Nicholl, Inc. v. Schick Dry Shaver, 9 Cir., 98 F.2d 511, 513, (referred to in the Brodie case) where he set forth the rule and exception in the following terms;
“The question of infringement was in this case, as it usually is a question of fact. Reinharts v. Caterpillar Tractor Co., *9 Cir., 85 F.2d 628, 630. The case does not, as claimed by appellant, fall within the i ule that, where the facts are undisputed, and the case can be determined by a mere comparison of structures, and extrinsic evidence is not needed for purposes of explanation or to resolve questions of the application of descriptions to subject-matter, the question of infringement may be determined as a question of law'.* United States v. Esnault-Pelterie, 303 U.S. 26, 30, 58 S.Ct. 412, 82 L.Ed. 625.” [Emphasis supplied]
While as Judge Mathews noted, both the Schick Dry Shaver case and the Brodie case fell outside the rule, the case at bar comes clearly within the rule above quoted.
The testimony before the trial judge revolved around the exhibits (full size commercial units) and embraced a discussion of the meaning of the term “stability” as used in the claims in the patent, the absence or presence of prior art, and appellee’s charge that appellant deliberately copied his device. The terms of the patent and the respective devices of the parties are also before us for our inspection. The facts are clear and undisputed and the question of infringement in this case can be determined by a comparison of structures and is a question of law. Therefore this court will examine for itself the device of appellant and determine as a matter of law whether it infringes the patent of appellee.
The. device patented by appellee, as the patent itself stated, was designed to “provide means for clamping a plurality of tanks into a unit which can be readily moved from place to place by tilting and rolling, together with means for reducing the danger of upset” (see the illustration). As the device was described in the patent seven tanks were to be manifolded together, but it is conceded that the number of tanks is immaterial and that the actual units employed commercially by both appellant and appellee contained only four tanks. Likewise it is conceded by all parties that the slight differences in the means used to clamp the tanks together and to secure them to the plate, are immaterial. The heart of the dispute is the nature of the plate, called the “truck” (see illustration) upon which the tanks rest and to which they are secured.
In appellee’s patented device the “truck” is a circular flat sheet of steel to which is attached a circular ring called the “track” (approximately the same diameter as the bottom of one tank and made of pipe) which is welded coaxially to the flat plate. The tanks rest upon this “truck” assembly. As is apparent from the drawing, this makes it possible to tip the unit sufficiently to balance it upon this ring or “track” and to roll the entire unit along in a straight line. (It is not rolled along on tile outer