It appears from the evidence that railroad locomotive wheels are composed of two parts,-the body of the wheel, called the wheel-centre, and a tire which surrounds it, substantially in the same manner in which the tire surrounds the felloes of an ordinary wagon wheel.
The invention of Mellon relates solely to a method of fastening tires upon locomotive wheel-centres. It appears from the record that, generally speaking, there are two ways of fastening these tires upon their wheel-centres; one by making the tire a little smaller in diameter than the wheel-centre, then heating it so that it will expand somewhat more than the difference between its diameter and the diameter of the wheel-centre, and in that condition slipping it on the centre and allowing it to cool, thus following the method of a blacksmith in shrinking a wagon tire upon a wooden wheel. Another method is to fasten the tire cold upon the wheel-centre by means of screws or bolts.
The former method is now almost universally used. In shrinking the tires on the wheels, the practice usually followed at present is to turn the wheel-centre, bore the tire in a cylindrical form, and rely solely upon the contraction of the tire by cooling to retain it upon the wheel.
A modification of this method is, in place of the wheel-centre and tire meeting each other in a cylindrical joint, to have some kind of a flange, lip, or shoulder to project either from the circumference of the wheel-centre or from the bore of the tire, to fill a corresponding groove or recess in the opposite part, so that when the tire has been shrunk on the wheel-centre it cannot be driven sideways, off the wheel against the resistance of this flange. The wheels exhibited in the drawings of Mellon's patent belong to this latter class.
The right of Mellon to the relief prayed for in the bill depends in part upon the construction to be placed on his letters-patent.
His counsel contends that they cover two things, which, it is claimed, are in substance set forth in his specification as follows:--
First, In having the wheel, or the tire which is to be fitted on the same, provided with a single flange arranged in such a manner that said flange, in connection with the ordinary flange on the tire, will keep the latter on the wheel.
Second, In constructing the tire with a rounded edge at one side of its inner surface, in order to prevent said edge from indenting and sinking into the periphery of the wheel, a contingency which would otherwise occur in consequence of the tire being stretched by use.
Conceding that the patent is to be construed according to the contention of the appellee, we are of opinion that he has not shown himself entitled to relief.
An inspection of the specification and drawings which accompany the letters-patent granted to Nehemiah Hodge under date of Nov. 18, 1851, shows precisely the contrivance first described in the specification of the appellee's patent. The drawing, representing a central cross-section of a car-wheel, appended to Hodge's specification, accurately illustrates the first alleged invention described in the specification of appellee's patent. His patent cannot, therefore, be held to include that contrivance. So far as that part of his alleged invention is concerned, the defence of want of novelty is conclusively established.
But there is another answer to this part of his case.
The act of July 4, 1836, c. 357 (5 Stat. 117), under which this patent was issued, requires that an applicant for a patent shall not only 'deliver a written description of his invention or discovery,' but 'shall also particularly specify and point out the part, improvement, or combination which he claims as his own invention or discovery.' This provision is substantially re-enacted in the act of July 8, 1870, c. 230 (16 Stat. 198), Rev. Stat., sect. 4888, and remains in force.
As a rule, therefore, the specification filed with the application for letters-patent contains a general description of the invention sought of be patented, which is followed by what is technically called the 'claim.' In reference to this latter part of the specification this court, speaking by Mr. Justice Bradley, has said: 'It is well known that the terms of the claim in letters-patent are carefully scrutinized in the Patent Office. Over this part of the specification the chief contest generally arises. It defines what the office, after a full examination of previous intentions and the state of the art, determines the applicant is entitled to.' Burns v. Meyer, 100 U.S. 671. See also Keystone Bridge Co. v. Phoenix Iron Co., 95 id. 274, 278.