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Steel & Tubes Inc. v. General Tube Co.

October 3, 1932


Appeal from the District Court of the United States for the District of New Jersey; William Clark, Judge.

Author: Davis

Before WOOLLEY, DAVIS, and THOMPSON, Circuit Judges.

DAVIS, Circuit Judge.

In this suit for infringement of claims 4, 5, 10, 14, 17, and 19 of the Johnston patent, No. 1,388,434, for a new and improved method and apparatus for butt-welding thingauge tubing, and of claims 3, 5, 6, and 9 of the Johnston patent, No. 1,435,306, for the product of the process, the District Court held both patents valid but limited their application to operations conducted at a speed in excess of thirty feet per minute. Both the plaintiff, Steel & Tubes, Inc., and the defendant, General Gube Company, appealed to this court. The plaintiff's appeal relates only to that part of the decree which limits infringement of both product and process to a speed in excess of thirty feet per minute. The defendant's appeal goes to the whole case, questioning both validity and infringement.

The process, and product thereof, of the patents in suit relate to the manufacture of steel tubing by folding a flat strip of steel into the form of a tube, having a lengthwise seam and then welding the tube in a particular manner by the use of electricity.

The patents in suit have been sustained and held infringed in three separate suits brought by the plaintiff or its predecessor. Elyria Iron & Steel Company v. Mohegan Tube Company, Inc., 7 F.2d 827 (C.C.A. 2); Steel & Tubes, Inc., v. Greenpoint Metallic Bed Company, 37 F.2d 172 (D.C., E.D.N.Y.); Steel & Tubes, Inc., v. S. Jackson Tube Company, Inc., 42 F.2d 760 (D.C., E.D.N.Y.). We are in accord with the conclusions reached in those cases. It would be useless, therefore, for us to go into a detailed discussion and repeat here what has been well said there.

Claims 4, 5, 10, 14, 17, and 19 of the process patent are in issue. Claim 19 is typical and is as follows: "The method of electrically butt-welding thin walled tubing which consists in applying welding pressure to a transverse, narrow zone of the tube stock intimately to close the seam cleft and applying impulsive welding current to traverse said zone, and in such continuous and rapid progression and with such pressure and current density as to produce a substantially continuous weld exhibiting in the seam a recurrent welding effect synchronizing with the impulses of the welding current."

In the Mohegan Case, the Circuit Court of Appeals for the Second Circuit compared the Johnston process with the process described in the Parpart patent (No. 658,741), which admittedly represented the highest development of the art of butt-welding thin-walled tubing by the electric resistance method before Johnston. We know of no better way to a ready understanding of the Johnston process.

Parpart caused the folded steel strip to be fed on a compression roll by copper electrode rolls, embracing the seam of the tubing, through which an electric current flowed to the seams of the stock. By a series of condensed shots of the electric current, the metal at the edge of the seams and adjacent thereto is heated to such a degree that the pressure exerted by the conducting rolls and the compression rolls (which are preferably offset from one-eighth to one-fourth of an inch from the compression rolls) combine "to mek a definite and material upset on each of the two meeting edge portions of the tube, the construction and adaptation of all parts being such as to insure such upsetting formation to a substantial degree." That is, the edges are pushed together to secure the weld beyond the damaged edges through which the series of shots of the heavy electric current must pass. Consequently, such a weld must result in metal that is pushed aside on the upset forming a considerable "burr" at the seam both on the outside and inside of the tube. There is no need to repeat the disadvantage of such a product.

In addition to the waste that resulted from the manufacture of the Parpart tubing and the costly process of removing the burr, it appears that the machines on which Parpart was practiced commercially could not be operated at a speed greater than twenty feet per minute because the weld required the metal to heat uniformly for some disstance back from the edges of the blanks.

Parpart used a certain correlation of the elements of speed, current, and pressure. The speed was such as to allow sufficient time for the electrical current to heat the metal to a fusion temperature for some distance back from the seam edges. Pressure was such as to insure a uniform "body-weld" back of the seam edges so that the burnt, damaged metal at the seam edges would be pushed out and extended.

Johnston's process was evolved to obtain a product that could be manufactured with speed and less waste and without the heavy burr.What Johnston did was to employ a new correlation of the variable elements of speed, current, and pressure. In the specification of his patent No. 1,435,306, he describes this as follows: "In practice I have found that for welding one-inch tubing of say .025 inch thickness, utilizing 60 cycle alternating current to supply the primary circuit of the transformer, the apparent welding current may be about 12,000 amperes at an apparent voltage of approximately 1.5 volts or a little more, as measured across the insulated gap of the roller electrodes at the nearest accessible point to their lines of contact with the tube being welded, and the speed of progression of the tube-stock may be over 70 feet per minute, to state a modest rate, which under proper current changes, can be considerably exceeded." That is, the cdhanges are susceptible of calculation. Johnston conceived the idea that there was too much pressure and heat. The heat extended far back from the edges. By just bringing the edges together with little pressure and only enough heat to heat the edges to a welding temperature, greater speed was obtained; the tube was better welded with practically no burr or upset. No waste resulted. The seam was welded by single impulses or shots of the alternating current. The characteristics of the product is a "stitch seam." "The resultant of this correlation of forces and elements was and is the stitch seam; a weld line which looks as if it had been sewed, that is, the 'recurrent' weld of the patent in suit. If any two of the following elements be known, the other can be computed, viz.: Speed per minute in feet, frequency of cycles of alternate current, and number of stitches per foot."

The plaintiff contends that when Johnston entered the field in 1919, the art of electrical resistance welding had been well developed and widely practiced. Among the numerous patents cited, Thomson, Ries, and Rietzal, Gorton, Baehr, and Guay are urged as anticipatents.

The Thomson patents, Nos. 347,140, 347,141, and 444,928 were considered by the Supreme Court in Thomson Spot Welder Company v. Ford Motor Company, 265 U.S. 445, 44 S. Ct. 533, 68 L. Ed. 1098, wherein it was held that the Thomson patents anticipated the Harmatta patent, No. 1,046,066 (1912), for spot-welding of metal plates. Thomson's patents describe a process of welding wires, bars, the formation of elongated, longitudinal joints by heating with an electric current of low voltage and high amperage and simultaneously applying pressure. He states ...

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