APPEAL FROM THE COURT OF CLAIMS.
MR. JUSTICE PITNEY delivered the opinion of the court.
Appellant brought this action in the Court of Claims under the Act of June 25, 1910, c. 423, 36 Stat. 851, to recover compensation for the unlicensed use by the United States in the Panama Canal work of his patented invention for "Improvements in cable cranes with gravity anchors." That court made findings of fact upon which it concluded as matter of law that there was no infringement of claimant's patent, and thereupon dismissed his petition. 52 Ct. Clms. 462.
From the findings it appears that claimant filed application for his patent July 18, 1895, and, upon such application, letters patent No. 551,614 were granted and issued, under date December 17, 1895, to his assignees Sarah E. Brothers and Maria A. Brown, to whom he had made assignment pending the application. Subsequently the letters patent were assigned to claimant, under date October 2, 1912, two and one-half months prior to their expiration by limitation on December 17, 1912. His claim to compensation is necessarily limited to this brief period, since there could be no assignment to him of any unliquidated claim against the Government arising prior to the time he became the owner of the patent. Rev. Stats., § 3477.
No question is made but that plaintiff's invention was broadly new, a pioneer in its line, and the patent entitled to a broad construction and the claims to al liberal application of the doctrine of equivalents. (See Brothers v. Lidgerwood Mfg. Co., 223 Fed. Rep. 359.) It relates to the method of erecting and operating a suspension
cable adapted to carrying a traveling crane or the like. Roughly speaking, the prior art consisted in supporting such cables upon rigid and unyielding towers at each end, so as to prevent an undue sagging of the cable under the strain of its load. Claimant's invention consisted in employing a rigid support or abutment at one end of the cable and what is called a "gravity anchor" at the opposite end, consisting of outwardly inclined shears with the cable attached thereto and a weight hung permanently from the shears on the opposite side, which weight, together with the weight of the shears, puts a tension upon the cable varying according to the weight of the structure and counterweight, combined with the degree of inclination of the structure; the operation of the tension device being automatically to take up the slack of the suspended cable when the load approaches the supports, with the result of permitting the load to be moved closer to the supports, with a given exertion of power, than before. There are other advantages not necessary to be specified. The essential feature of the patent is a non-yielding support or anchor at one end of the cable, and a yielding, tilting, or rocking support at the opposite end, consisting of outwardly inclined shears or some equivalent structure held movably at the base, and a counterweight on the outer side. It is to be observed that rigidity of the head tower is a sine qua non, necessary to produce tension of the cable; yielding supports at both ends would be a contradiction of terms, since with such an arrangement there would be no support, and the entire structure would collapse under its own weight. The importance of this will appear.
In the construction of the Panama Canal the Government installed in the year 1909, and maintained and used continuously thereafter until the expiration of the Brothers patent, one single cableway and six duplex or double cableways which are complained of in this case
as infringements. As to the mode of construction, maintenance, and operation of these cableways, the findings of the Court of Claims are as follows:
"The single and the duplex cableways were similar in general design and construction except that the towers of the former supported a single cable, while those of the latter supported two cables, parallel to each other, at a distance of 18 feet apart, and each operated independently of the other, the length of the towers longitudinally of the canal cut being of proportionate dimension for the accommodation of the two cables. The towers were of structural steel construction; and taking the duplex cableways for illustration, each tower in vertical cross section from front to rear was in the shape of a right-angle triangle, with a base of approximately 50 feet, a perpendicular or vertical height of about 85 feet, and a hypothenuse of about 98 feet, with a length of about 38 feet longitudinally of the canal. The two towers of the cableway stood facing each other, on opposite banks of the canal cut, with their hypothenuse faces toward the cut. The cable span across the cut between the tops of the towers was approximately 800 feet. The cables used were 2 1/4-inch steel-wire cables having a rated breaking stress of 200 tons. The cables were supported by headblocks or saddles at the tops of the towers, and their ends were carried down and firmly anchored to the counterweighted bases of the towers
"Rigidity of the towers was desired; and in order to secure this and hold the towers rigid against any tendency to tip, tilt, or yield under the stress of the suspended cables and their loads, the platform base at the rear side of each tower -- that is, the side farthest from the canal cut -- was counterweighted by a block of cement concrete of over 150 tons weight, cast about the structural steel ...