This suit was brought by appellants' testator, Philo D. Beckwith, against the appellee for the alleged infringement of three letters patent, viz. No. 123,142, issued January 30, 1872; No. 135,621, issued February 11, 1873; and No. 206,074, issued July 16, 1878,-all for improvements in heating stoves. The defenses set up and interposed were that the patents were all void for want of novelty and patentable invention. Pending the suit the patentee died, and the cause was revived and proceeded in the name of his executors. The court below dismissed the bill, and complainants appeal to this court to reverse that decree.
The first patent, issued January 30, 1872, relates to an improvement in stoves, wherein an exposed fire-pot section, cylindrical in shape, and tapering downwardly, is fitted into the upper end of a hollow ash-pit section. This fire pot has formed on the inner side of its lower end an annular flange, on which the grate rests. The theory of the patent is that this flange, which may be cast on or made separate from the flre pot, and riveted or otherwise fastened to it, is made of such a width that it will collect upon it a bank of ashes, which will have the effect of preventing undue expansion of the fire pot at the point of junction with the ash pit; or, in other words, the collection of ashes on the flange will prevent such an expansion of the lower end of the fire pot as would cause it to leave its seat on the ash pit, and expose an open joint at this point. The inventor stated in his application that he had found that the expansion of the fire pot is so great without the flange that the stove proves a failure, but, with the flange cast on it at the point designated above, the joint will remain tight during the lifetime of the stove. The novelty involved in the patent consists entirely of the tapering cast-iron fire pot with the annular flange or shelf formed on its inside lower end at the point where it joins the ash pit, and upon which flange the grate rests. The single claim is 'the tapering cast-iron section, B, with the flange or shelf, c, framed on it, as described and shown.'
It was claimed by the appellee that this feature of the invention was so common in actual stove construction at the time the patent was issued as to be deemed obvious, and that prior patents, attaining the same results, had been granted, which practically covered the same design or contrivance included in this particular patent. In support of this contention it was shown that a patent had been issued to Benjamin Brownell, on September 18, 1868, for a soft-coal hot-air furnace, in which it appears from the drawings set out in the record that a tapering fire pot is one of the elements of his invention, although it is not described in the specification. The drawings also indicate, and it was established by expert testimony, that this tapering fire pot had a flange on the inside lower end, upon which the grate rests. At the trial, a model of the Brownell patent was introduced, in which it was shown that the model differed from the patent drawings in having the projecting flange at the lower end of the fire pot formed on the ash pit, instead of on the fire pot.
The appellee further showed that a patent was issued to A. Atwood, May 14, 1850, (No. 7,356,) which has a flange projecting under the lower edge of the fire pot as wide as the outer rim of the grate. This flange is upon the ash pit, and not upon the fire pot. A patent issued to Bush & Richards (No. 171,129,) November 19, 1867, shows a construction like the Atwood patent, except that the fire pot is tapering.
It therefore appears in these three patents offered by the appellee, in support of its contention that the invention of the appellants had been anticipated, that they contain a clear and accurate representation of the contrivance of the Beckwith patent; that, even if the flange was formed on the ash pit instead of on the fire pot, it was the equivalent thereof, because it performed the same function in the same way; and that the only function of the flange would be to collect a ring or bank of ashes at the base of the fire pot when the stove was in use.