Opinion of the Court 50. None of the claims of plaintiff's patent #1,306,768 involved in this case has been infringed. Claims 3, 10, 11, 12, 13, 14, 15, 17, 18, and 19 are invalid. It is unnecessary and we make no finding as to the validity of claims 1, 2, 4, 5, and 6. The court decided that the plaintiff was not entitled to recover. LITTLETON, Judge, delivered the opinion of the court: Plaintiff alleges unauthorized use under the act of June 25, 1910, 36 Stat. 851, as amended by the act of July 1, 1918, 40 Stat. 704, 705, by the War and Navy Departments of the United States of a patent granted to him in 1919, as set forth in the findings, for a certain aeroplane retractable landing gear. Defendant first filed a plea in bar claiming that if it had used any feature of plaintiff's patent it had a license to do so. This plea was overruled without prejudice and is now renewed. The other contentions of the defendant upon which it bases its defense that plaintiff is not entitled to recover are set forth in the preliminary statement preceding the findings of fact. Upon the whole record we are of opinion that plaintiff is not entitled to recover for several reasons which will hereinafter be mentioned. 1. If the features of the patent in suit, as expressed in the claims, alleged to have been infringed by the defendant can be held to involve invention, it is obvious from the facts that the grant under such claims is so narrow, in view of the prior art, that none of the features or elements of the aeroplane landing gear frame structures of the defendant can be held to have infringed plaintiff's patent. French patent, 111,574, to Penaud and Gauchot (Finding 29) discloses a retractable landing gear, the frame members of which are "housed in the general shapes of the nacelle", and points out that "impressions in the surface of the nacelle receive the different pieces of these legs." Given its ordinary meaning, we think this language discloses to a man skilled in the art the use of openings in the fuselage which are automatically closed, at least to the extent that the fuselage openings on the defendant's aeroplanes are closed by the landing-gear Opinion of the Court frame members alleged to infringe when the landing-gears are retracted and the landing-gear frame members lie within such impressions. The language of the specification of this patent also discloses to a man skilled in the art the formation of the housings for a retractable landing-gear frame of an aeroplane, the openings of which housing substantially conform to the shape of the struts of the landing gear. We cannot assume that the provision for "impressions in the surface of the nacelle" to receive the landing-gear frame members when the landing gear is in a retracted position means impressions much larger or of different shape than the landing-gear frame members which such impressions are desired and intended to receive. The usual and ordinary meaning of such language is that such impressions in the fuselage to receive the landing-gear frame struts, when in a retracted position, would substantially conform to the dimensions of the landing-gear struts. This is especially true in this instance, inasmuch as the specification of this patent also points out that the place of the housing of the landinggear frame members may be surrounded with coverings or suitable troughs. Moreover, with reference to infringement, the file wrapper discloses such limitation with reference to claims 3, 10, 11, 13, 14, 17, 18, and 19 relating to the closure of the fuselage openings when the landing gear is in a retracted position that plaintiff is estopped to allege infringement by the Government structures disclosed and described in the findings. The broad claims originally made by plaintiff were rejected as not involving invention and as being anticipated. Thereafter, during consideration of the application, the claims were reframed and certain new claims were submitted. Upon further consideration certain claims with reference to a closure of the fuselage openings upon retraction of the landing gear so as to provide a substantially continuous outer fuselage surface were rejected as being anticipated by the U. S. patent to Francis referred to in finding 25. This action was taken prior to and on July 9, 1918. Thereafter, on September 20, 1918, plaintiff filed amendments of certain claims and added three new claims which afterward became claims 17, 18, and 19 of the patent in suit, and in a written Opinion of the Court statement filed in support of the allowance of the claims over Francis stated: "The Francis construction is impractical in that his door does not form a flush closure and is closed by the operator after the storing of the chassis and independently of such storing operation. A favorable consideration of the claims presented herein is therefore respectfully asked." It will be seen therefore that plaintiff during prosecution of his application, which matured into the patent in suit, interpreted his claims relating to the matter of closing the fuselage openings as being limited to such a closure as would form a strictly flush fuselage surface. It is well established that a representation made to secure a patent narrows the grant, operates as a limitation, and is binding on the patentee; and that limitations imposed by an inventor, especially those introduced after rejection or proposed rejection of certain claims, must be strictly construed against the inventor and be looked upon as disclaimers. A limitation is not rendered ineffective because unnecessary and self-imposed. 2. Claims 3, 10, 11, 13, 14, 17, 18, and 19 are invalid for the reason that, in view of the prior art, they involve no more than the exercise of mechanical skill and are anticipated by U. S. Patent No. 1,083,394, January 6, 1914, to Francis (Finding 25) and French patent 474,585 to Lawrence (Finding 32). The patent does not, as plaintiff contended before the Patent Office, show a closure for the fuselage opening, into which the landing gears are retracted, which is operated manually by the pilot after the landing gears have been retracted. On the contrary the Francis. patent discloses a closure for the fuselage opening which is operative automatically upon the extension or retraction of the landing gears and also discloses that this closure, when the landing gears are retracted, forms a substantially continuous outer fuselage surface. During the trial of this case plaintiff did not contend that the Francis patent failed to show an automatic closure, but raised a question as to the operativeness of the closure for the fuselage opening disclosed in the specification and drawings of the Francis patent. This objection was directed to drawing, Fig. 3, of the Francis patent and it was based upon the fact that in this 64834-38-CC-vol. 86-26 Opinion of the Court drawing, the bearing arm 36 and the connecting cable for automatically closing the opening in the fuselage are on one side of the plane of rotation of the wheel and the hinge of the door is attached to the fuselage on the opposite side. No contention was made or proof submitted at the hearing that the closure for the fuselage opening described in the drawings and specification of the Francis patent operated or was intended to be manually operated by the pilot after the landing gears were retracted. With reference to the operativeness of the structure shown in Fig. 3 of the Francis patent, defendant's expert witness Browne was asked, upon crossexamination, the following question: "I ask you as a patent expert whether it would be possible in any way to have that wheel come down to the ground completely enclosed between its cord and its bar if that were the case, and ask you to tell where the hinge is located. Also, now that you have interpreted that patent in that way [as functioning automatically] I would like you, because it is a very important thing, to state whether there is anything in the specification which corroborates that point of view." To this question the witness replied "There is nothing in the specification. I, myself, have sufficient doubts as to its operativeness so that I did not refer to this patent." This was the extent of the testimony of this witness concerning the non-operativeness of the structure and that opinion was based wholly upon inferences apparently drawn from the location of the hinge of door 37' shown in drawing, Fig. 3. The court is not bound by expressions of opinions by expert witnesses. Head v. Hargrave, 105 U. S. 45; The Conqueror, 166 U. S. 110. Expert testimony as to the meaning of patent specifications is only permissible to enable the court to understand the specification, and if the court understands the specification without such testimony it is not necessary. Cf. Kohn v. Eimer, 265 Fed. 900. An expert may not be permitted to state that the omission of a connecting mechanism would be a "fatal fault." It is proper for the witness to describe the results of omission of the connecting mechanism but his opinion that the omission is a fatal fault goes beyond the province of an expert. National Cash-Register Co. v. Leland, 94 Fed. 502. A mistake in a particular draw Opinion of the Court * * * ing does not render a patented device inoperative or prevent the court from considering the entire disclosure in the specification and other drawings of the patent as a proper reference in the prior art if, by considering the language of the specification and the drawings, it is clear what the patentee intended by the language used in the specification. As set forth in Finding 25, it is clear that the Francis specification has reference to the closing of all the apertures in the fuselage and relates to the rear landing gear, as well as to the landing gear in the forward portion of the plane. The language of the specification here pertinent, is, "when the ground wheels have been telescoped in the body the apertures of the chambers may be closed by doors 37' 99 In other portions of the specification the patentee speaks of the "front wheels," the "forward wheels," and the "rear wheels." This language, when considered in connection with Fig. 2, as well as Fig. 3, of the patent, clearly discloses to a man skilled in the art a closure for the fuselage opening which is operated automatically upon the extension or retraction of the landing gears. It is also clear from consideration of the specification and drawings of this patent that it would be within the skill of an ordinary mechanic to hinge the door 37′ shown in Fig. 3 on the same side of the plane of rotation of the front wheels as the operating cable. See Dicks Press Guard Mfg. Co. v. American Hardware Corp., 247 Fed. 338, 339, wherein it was held that although a prior patent showed the "gates swinging the wrong way the mistake is one which any mechanic could correct and does not affect the extent of the disclosure [of the prior art] to the skilled man." From the specification and drawings of the Francis patent we think it would also clearly be within the skill of an ordinary mechanic to place the front wheels of the aeroplane on the inside of bearing arm 36 as such wheels are shown in drawing Fig. 2 or to hinge the door 37′ on the inside of the fuselage sheathing so that the door would lie wholly within the pocket and flush with the outer surface of the sheathing, thereby providing a perfectly smooth fuselage surface when the landing gears are in a retracted position. In this connection see, also, finding 32 with reference to the French patent to Lawrence issued December 12, 1914. |