This is a suit in equity, brought by the National Car-brake Shoe Company, a corporation, against the Lake Shore & Michigan Southern Railway Company, in the circuit court of the United States for the Northern district of Illinois, for the infringement of letters patent No. 40,156, granted to James Bing, as inventor, October 6, 1863, for 17 years, for an 'improved shoe for car-brakes.' The bill was filed June 7, 1880,-less than four months before the expiration of the patent. The answer which was filed October 4, 1880, two days before the patent expired, denies infringement, and alleges that the thing patented had been in public use or on sale, with the consent and allowance of Bing, for more than two years prior to his application for the patent, and that the invention had been abandoned by him to the public. There is no defense of want of novelty or patentability set up in the answer. The replication was filed on the same day with the answer. No proofs were taken, but five days after the filing of the replication, and three days after the patent expired, the parties entered into the following written stipulation:
'It is hereby stipulated by and between the parties to the above-entitled suit, for the purposes of said suit and no other, as follows, to-wit: (1) That the patent sued on, No. 40,156, issued to James Bing, October 6, 1863, may be considered as formally offered in evidence, and that complainant is the exclusive owner thereof; (2) that the small brass model offered by complainant, and marked 'Complainant's Exhibit, Bing's Brake-shoe,' is a correct representation of the invention described in said patent, except that defendant claims that said model has not enough rocking motion; (3) that the small wooden model offered by defendant, and marked 'Defendant's Exhibit A,' is also a correct representation of the said invention, except that complainant claims that said model has too much rocking motion; (4) that defendant has used two different kinds of brake-shoes, both of which are claimed by complainant to be infringements of the second claim of said patent, but as to both of which infringement is denied by defendant; (5) that the first of said brake-shoes is constructed in all respects like that described in said patent, except that the two parts, viz., the shoe and the sole, are fitted on each other so snugly as to have no rocking motion; (6) that the second of said shoes is correctly represented by the small wooden model marked 'Defendant's Exhibit B,' and that it also has no rocking motion; (7) that brake-shoes having a detachable sole attached to the shoe by bolts passing through the shoe and sole at right angles to the face of the sole, one at the top and one at the bottom, and secured by nuts screwed on to the inner ends of said bolts, so that the sole could be taken off upon the removal of said bolts, had been known and used in the United States for some years prior to the said invention of said Bing, and that the small wooden model marked 'Defendant's Exhibit C' is a correct representation of said brake-shoes; (8) that said shoe last mentioned was suspended from the truck by a hanger or clevis attached to a bolt passing through a hole at the top of said shoe, as shown in said model; (9) that neither of said brake-shoes used by defendant has the lateral rocking motion described in said patent, or infringes the first claim of said patent; (10) that if the court be of the opinion that said lateral rocking motion forms no part of the second claim of said patent, then the first of said defendant's brake-shoes above mentioned is admitted to be an infringement of said claim, and the decision as to that shoe shall be in favor of complainant, provided the court shall also be of the opinion that there is, on that construction, any patentable novelty in said claim. But, if the court be of the opinion that said lateral rocking motion does form a part of said second claim, or that there is no patentable novelty in said claim if so construed as to exclude said rocking motion, then, in either of these cases, the decision shall be in favor of defendant as to said first shoe; (11) that if the court shall be of the opinion that said lateral rocking motion forms no part of the second claim, and that defendant's second brake-shoe, viz., that the defendant's Exhibit B is, in its mechanical construction, substantially the same as the combination described in said claim, then the decision as to that shoe also shall be in favor of complainant, provided the court shall be of opinion that there is any patentable novelty in said claim when so construed.