(after stating the facts as above). Machines for capping and compressing can heads and double-seaming' without the use of solder were old in the art when Wilson and Sumner entered the field. Two steps mark the operation: First, that by which the flange on a cap is bent partly around the can and body flange so as initially to interlock the flanges; and, second, that by which the interlocked flanges are rolled or curled to complete the seam. This litigation pertains principally to the first operation. Some of the earlier devices had two seaming operations and encircling seamirig m§ans, but it is not shown that any had continuously operating two turrets with a transfer means between, and means on the first turret for effecting a first seaming operation, and means on the second turret for producing' a second and final seaming operation. It is on the combination of the parts and features of the whole machine that patentees claim a monopoly.
The proof is satisfactory that the structure of the "Wilson and Sumner patent (for brevity called the Wilson patent) is such, that in the first operation the gears are so arranged with relation to the rack that the can will make in the first turret approximately something over a single revolution, and that the tops are so tightly clamped on the cans during the spinning operation that the spinning' or turning does not discharge any of the contents from, the can. One of the expert witnesses testified: “It is this turning of the can in conjunction with the specific seam-forming device employed by plaintiffs by which forming the seam is effected.” In defendants’ machine the seam between the can to>p and the can is formed by holding the can practically stationary as it advances, and rotating the seam-forming mechanism relatively to the can. It is argued that the seaming rolls of defendants’ device and the levers carrying the rolls are equidistant and opposedly disposed around the central axis of the rotating portion of the head, and so a quality of balance essential for speed and efficiency is attained. In operation, however, defendants’ machine makes a bending of metal like that made in the first seaming-operation, although the seaming rollers appear to impinge on the can and top to a somewhat less extent than do the rings in the Wilson, machine. The fact that in Wilson’s device there is a lateral movement of the ring in the first seaming means is not important; unquestionably impingement occurs in rolling contact with the can. top.
Appellants refer to many patents in the prior art. Considering the more important: Brenzinger, No. 813,482, February 27, 1906,, devised a ea.n-heading machine of two sta-tions, one for each operation, with a moving belt for carrying a can from one station to the other. Tie did not show two' revoluble carriages; nor did be provide for coincident delivery of cans and caps to a first rovoluble carriage. Moreover, Ms machine had an intermittent movement. In his seaming means for the first operation he had rollers which rotated about the can to form the curl of the seam. Black, No. 858,785, July 2, 1907, had two turrets and a continuously operating mechanism, and a turret with four spindles with flanging mechanism, and a transfer wheel with a disk and four can-receiving depressions in its periphery. In the transfer wheel ho provided for the can receiving its top and delivery to the second turret. He shows the curler eng'aged while the compressor is diseng'aged, and both operations are performed on the same spindle while the; turret is rotating. Distinction between Black’s and Wilson’s devices is that, although Black shows two turrets, he does hot show one for the first seaming operation and the other for the second seaming. He rotated the rollers about the can, which is held against rotation around its own axis. The master commented upon Black’s machine, saying that it was seven years after Black’s patent that Wilson filed for a two-turret, continuous motion, double-seaming machine “in response to the demand created by the enormous growth of the packing industry, and it would seem in anticipation of urgent demands for a speedy machine created by the war.” Guenther, No. 1,049,227, December 31, 1912, showed means for performing the first seaming operation by a pair of curling rollers carried on a sleeve adapted' to be rotated around the central axis of the can; the can being centered by a flange cut out for the passage of the J overs and curved rollers. Guenther’s machine was intermittent. Wegner, No. 1,104,751, July 21, 1914, employed a single turret type machine in which the cans with can tops are rolled against the stationary seam-forming tool. His seaming means do not lake a circular course of travel *318around the cans, nor do they physically encircle the can and center it. In Wilson’s mechanism continuity is due to the use of the two turrets for seaming with cap and can delivered to a first turret and transfer means operating between the revolving turrets all in synchronism by means of gears, shafts and spindles devised and arranged for the purpose.
Appellants rely much upon the file wrapper which shows that Wilson’s claim 2 (originally claim 6) was rejected and then amended to avoid references (Brenzinger, No. 813,482, Black, No. 858,785, and Wegner, No. 1,104,751) cited against them. Originally the claim did not have the words “encircling the can top” before the word “for,” and prior to Wilson’s amendment considerable correspondence was had between the Patent Office and appellants; Wilson contending that the references to Brenzinger and Black were not well founded. Conceding the principle that by amending Wilson is limited to the form and language of the claims as allowed, nevertheless he is not limited to any detailed specific construction to avoid any x-eferenee cited against it, nor is he estopped from claiming by the amended claim every improvement and combination which he has invented and which was not disclosed by those references. National Hollow Brake Beam Co. v. Interchangeable Brake Beam Co., 106 F. 693, 715, 45 C. C. A. 544; Owens Co. v. Twin Separator Co., 168 F. 259, 93 C. C. A. 561; Auto Pneumatic Action Co. v. Kindler & Collins, 247 F. 323, 159 C. C. A. 417.
To apply tlxat principle: • The words “eeeentric encircling ring” are not found in the amendment to claim 2; nor is the claim limited to exact features, as, for example, was the claim discussed in Wilson & Willard Mfg. Co. v. Union Tool Co., 249 F. 729, 161 C. C. A. 639, certiorari denied 248 U. S. 559, 39 S. Ct. 6, 63 L. Ed. 421. Therefore there should be no meaning put upon the words “encircling can top” by which thei’e is a limitation to the eeeentric encircling ring, unless the specifications and the drawings, which showed eccentric rings, taken in connection .with Wilson’s claim 2, make it obvious that he has limited his claim to the use of eeeentric rings. The Patent Office may have distinguished Wilson’s type of machine from others by reason or specification of the encircling in the first seaming - means, but such distinction does not necessarily limit all other elements to that specified eccentric ring with a earn bearing upon it. Interpretation of the claim as allowed may be broad enough to cover improvement other than is disclosed by the references cited against it. In National Hollow Brake Beam Co. v. Interchangeable Brake Beam Co., supra, the court, through Judge Sanborn, said: “The description in a specification or drawing of details which are not, and are not claimed as, essential elements of a combination, is the mere pointing out of the better method of using the invention. * '* * A reference in a claim to a letter or a figure used in a drawing and in the specification to describe a device or an element of a combination does not limit the claim to the specific form of that element there shown, unless that particular form was essential to, or embodied the principle of, the improvement claimed.”
We regard claim 2, in the element of encircling means, as entitled to a construction which includes a fairly liberal range of equivalents. The difference in the use of a mechanical equivalent does not' avoid infringement. In Eibel Process Co. v. Paper Co., 261 U. S. 45, 43 S. Ct. 322, 67 L. Ed. 523, the court, through the Chief Justice, clearly reiterated the doctrine that where an inventor, though not a pioneer in the sense of having created a new art, has made a very useful discovery which has substantially advanced the art, his patent, though but an improvement on an old machine, may be entitled to liberal treatment. That same principle was applied by this court in Smith Cannery Co. v. Seattle Astoria Iron Works (C. C. A.) 261 F. 87. Defendants therefore cannot escape infringement by adding to or taking from the patented device by changing its form, or even by making it somewhat more or less efficient, while they retain its principle and mode of operation, and attain its results by the use of the same or equivalent mechanical means. Lourie v. Lenhart, 130 F. 122, 64 C. C. A. 456; Letson v. Alaska Packers Association, 130 F. 129, 64 C. C. A. 463; Eck v. Kutz (C. C.) 132 F. 758. By varying the encircling means, but producing the same results in substantially the same manner, there is infringement. Both physical and mechanical encircling with centering are found in defendants’ machina Union Paper Bag Machine Co. v. Murphy, 97 U. S. 120, 24 L. Ed. 935; Kinloch Telephone Co. v. Western Electric Co., 113 F. 659, 51 C. C. A. 362; Auto Pneumatic Action Co. v. Kindler & Collins, supra; Pangborn Corporation v. Sly Mfg. Co. (C. C. A.) 284 F. 217.
*319Without restating the mechanisms in further detail, the conclusion we must reach is that claim 2, when applied to Guenther’s patent, No. 1,441,195, January 2, 1923, reads upon his practice and deviee.
Claim 4 of Wilson’s patent was not amended in the Patent Office. In its detail it relates to a second turret. It is a description of the means for revolving the spindles or the seam-rolling means, and does not require the spinning of the scam-forming means or of the can that is being seamed, nor does it describe the seaming means as encircling the can top. The master’s report contains an elaborate examination of the claim (4) in relation to defendants’ structure and Guenther’s letters patents, Nos. 1,441,195, January 2, 1923, 1,440,143, December 26, 1922, and 1,450,418, April 1923, and correctly concludes that the elements of the claim are found in defendants’ machine, P-24. Defendants have added a shaft in one turret of their machine, but the mode of operation is not ehanged. It appears too that Wilson’s machine has had substantial recognition, i£nd in our opinion it constituted invention.
We bold, therefore, that the patent in suit is valid, and that claims 2 and 4 were infringed, and that plaintiffs are entitled to an accounting.
The record shows that the suit was originally brought under four patents. As to one (a machine pertaining to seam-forming means and specific claims) no proof was taken before the master. As to two others (No. 1,250,406; a can top feeding deviee, and No. 303,348, a can-feeding device) the master found no infringement, hut did find that the three patents referred to were valid. The District Court held that the three patents were valid and not infringed. These several patents are not directly involved in this appeal, for the reason that appellees herein took no eross-appeal from the interlocutory decree of the District Court. Appellants nevertheless urge as error the court’s award of all costs to plaintiffs, appellees herein. It appears to have been necessary for the master to hear evidence with relation to the several patents, and we think his recommendations that in the proceedings had before the District Court costs should be assessed two-thirds against plaintiffs and one-third against defendants was equitable. But we think all costs on this appeal should he assessed to appellants.
As modified, the decree of the District Court is affirmed.