Nash Motors Co. v. Swan Carburetor Co., 4454.

• Decision Date: 21 June 1939
• Docket Number: No. 4454.,4454.
• Citation: 105 F.2d 305
• Parties: NASH MOTORS CO. v. SWAN CARBURETOR CO.
• Court: U.S. Court of Appeals — Fourth Circuit

105 F.2d 305 (1939)

NASH MOTORS CO. v. SWAN CARBURETOR CO.

No. 4454.

Circuit Court of Appeals, Fourth Circuit.

June 21, 1939.

Merrell E. Clark, of New York City (Charles H. Walker, of New York City, on the brief), for appellant.

F. O. Richey, of Cleveland, Ohio (F. M. Bosworth, of Cleveland, Ohio, Edwin F. Samuels, of Baltimore, Md., and Richey & Watts, of Cleveland, Ohio, on the brief), for appellee.

Before PARKER, NORTHCOTT, and SOPER, Circuit Judges.

SOPER, Circuit Judge.

The District Court held in this case that the Nash Motors Company had infringed United States patent No. 1,536,044 of 1925 to John W. Swan, relating to the inlet manifold in an internal combustion engine. A decree for an injunction and for damages and profits, to be fixed by a special master, was granted to the Swan Carburetor Company, owner of the patent.

The same patent has been the subject of litigation in Swan Carburetor Co. v. General Motors Corp., D.C., 42 F.2d 452, affirmed on appeal on a procedural question in General Motors Corp. v. Swan Carburetor Co., 6 Cir., 44 F.2d 24, and also in General Motors Corp. v. Swan Carburetor Co. and Reeke-Nash Motors Co. v. Swan Carburetor Co., 6 Cir., 88 F.2d 876. In these cases the validity of the patent was sustained. The Nash Motors Company, defendant in the District Court in the pending case, was in privity with the appellant in Reeke-Nash Motors Co. v. Swan Carburetor Co., supra, and hence is bound by the decree there rendered. In that case, certain manifolds manufactured by the Nash Motors Company, designated herein as Nash No. 1 or the adjudicated Nash manifolds, were held to be an infringement of the patent. The answer in the pending suit disclosed that the Nash Company is now using a different type of manifold, called herein the Nash No. 2 or the accused Nash manifold, and the plaintiff moved to strike out the portions of the answer referring thereto on the ground that the proceedings in Reeke-Nash Motors Co. v. Swan Carburetor Company in the Sixth Circuit were of such a nature that the Nash Company is estopped here to deny infringement not only by the first, but also by the second group of manifolds. On appeal from an order refusing to strike, we held, 4 Cir., 98 F.2d 115, that the defendant was not so estopped, but was entitled to show, if it could, that its second group of manifolds do not infringe the patent.

The charge of infringement is based upon the similarity of the second group of Nash manifolds to the first group, which were adjudicated to infringe in Reeke-Nash Motors Co. v. Swan Carburetor Company, supra, and upon the holding in that case that the first group resembled the structure of the Swan patent more closely than the Matheson manifold, a prior art structure upon which the defendant in large measure relied. The defense in the pending suit is based on the contention that after the decision of Swan Carburetor Co. v. General Motors Corp., supra, the Nash Company discontinued the use of its first group of manifolds which were like those held to infringe in that case, and has since used the second group, which are in all essential details the same as the Matheson structure. The Nash Company was in fact using the second group of manifolds at the time that the Reeke-Nash case was reached for trial. Thus we have two opposing principles bearing on this case and leading to opposite results, on the one hand, the estoppel of the judgment in the Reeke-Nash case, whereby the defendant is precluded from denying the validity of the patent or that its first group of manifolds infringes the patent, and on the other hand, the limitation of the prior art upon the scope of the patent whereby the plaintiff is precluded from claiming that the patent is broad enough to include the Matheson structure. Both principles must be given effect if it is reasonably possible to do so.

The invention relates to a method and a means, such as an intake manifold, of conducting and delivering a mixture of air and fuel from a mixing device, such as a carburetor, to the cylinders of an internal combustion engine. We are concerned only with a single claim of the patent, No. 20, which describes the means employed in the following terms:

"20. In an inlet manifold, a distributing chamber having a single inlet conduit and three branch conduits, one of the walls of the chamber being opposite the inlet duct and symmetrically formed and situated with reference to the branch ducts so that entering fluid may be influenced by said wall uniformly in all directions transverse to the entering stream, and the branch conduits being of substantially uniform shape throughout and at any turn thereof presenting similar walls shaped and situated so that passing mixture may be influenced thereby in a manner to distribute equally to cylinders to which said turns may lead."

This description indicates that the device consists of an inlet conduit, a distributing chamber and three branch conduits of uniform shape throughout, so arranged that the fluid from the inlet conduit enters the distributing chamber and then strikes against the opposite wall thereof, whereby the stream is influenced to move uniformly in all directions transversely to its prior course. Thereby the fuel is sent on its way to the cylinders, but before reaching the cylinders, it again strikes against walls so situated at the turns into branch conduits that the mixture is distributed equally to the cylinders to which the turns may lead.

This description is quite general in its terms and gives scant information of the means devised to accomplish the desired result. It is necessary, therefore, to turn to the specifications for a more precise description of the invention. There we are told that the main object is to deliver the mixture of air and fuel from the carburetor uniformly to all the cylinders; and that the movement of the fuel from the intake conduit to the successive cylinders is determined by the firing order of the cylinders, so that the fuel passes through a different branch conduit each time a cylinder takes its charge. The mixture of vaporized gasoline and air, as it comes from the carburetor, contains particles or globules of the fuel in liquid state, which, to some extent, are still in that state when they reach the cylinders. The volume of air required is many hundred times the volume of the liquid particles so that misdirection of the latter greatly affects the ratio of the entering constituents. The means by which the mixture is carried in correct proportions to all the cylinders with equal facility is the gist of the patent. A distributing chamber is formed by the juncture of a vertical conduit or riser, which connects the carburetor at its lower end to a horizontal conduit or header situated above. Intersecting the header on the same horizontal plane in a six cylinder engine are three branch conduits, of which one proceeds from the middle, and one from each end of the header. Each branch conduit serves two cylinders. The distributing chamber, and the bends at the ends of the header, where it joins the end branches, are the portions of the manifold to which claim 20 of the patent particularly refers. The shape of the conduits and the manner in which the riser and the branch conduits meet the header create the desired influence upon the course and direction of the mixture in its passage through the structure, so that there is no deflection of the mixture which would divert more fuel to one exit opening than another, or which would disturb the ratio of the constituents.

The greatest separation of the constituents of the mixture or disturbance of fuel ratios takes place whenever there is a turn or change in the direction of the moving mixture, because the centrifugal force tends to throw the heavy liquid particles out of the line of travel and to separate them from the mixture. The patentee offsets this tendency in his preferred construction by making "all of the manifold, including the intake, the distributing chamber, branches and outlets, angular in cross section," and by making the angles sharp where the riser and the branch conduits join the header. By this formation the moving mixture is projected against an opposing wall of the header at the turns and a remixing of the constituents is effected.

It is important to note, however, that the patentee does not confine himself to this precise construction. He says that an angular construction of the various members of the manifold is preferable, "but round, hexagon, octagon or other cross sectional shapes may in instances be resorted to. For example, in Figure 9, I have shown a detailed section of one of the branches with its turn leading to an end cylinder or cylinders, the inside angle of the turn being sharp and the outside rounded. Good results may be obtained in a modification of this character in view of the fact that the wet constituents of the fuel will be caused to be projected beyond the sharp inside angle into the air at the turn, effecting a remixing of the constituents incident to the change of direction thus created at the turn." (Italics supplied.)

In Swan Carburetor Co. v. General Motors Corp., D.C., 42 F.2d 452, in which an excellent description of the patent is given, Judge Westenhaver thus summarizes the teaching of the inventor, 42 F.2d at page 455:

"His fundamental conception is and was that by changing abruptly at right angles the line of travel of the mixture, and by eliminating all obstructions, curves, or recesses in that line of travel, the tendency of the wet particles to collect at one place more than another would be avoided, and that, whenever the line of travel was thus abruptly changed at right angles, the wet particles would be thrown toward or beyond the main current and be mixed with the air and fully vaporized. In this way he asserts that an area of agitation or turbulence or mixing zone is created at each intersection where a sharp right-angled...