U.S. Supreme Court
Railway Company v. Sayles, 97 U.S. 554 (1878)
Railway Company v. Sayles
97 U.S. 554
1. A party who invents a new machine never used before and procures letters patent therefor acquires a monopoly as against all merely formal variations thereof, but if the advance towards the thing desired is gradual and proceeds step by step, so that no one can claim the complete thing, each inventor is entitled only to his own specific form of device.
2. Double brakes, operating upon the two trucks of a railroad car at the same time, by a single force through the medium of connecting rods, had been publicly used before Thompson and Bachelder invented the Tanner brake. Only the specific improvement which they made could therefore be covered by the letters patent for that brake. The latter were not infringed by the Stevens brake, for which letters patent No. 8552 were issued Nov. 25, 1851, though it was invented after the Tanner brake, inasmuch as it is another and different specific form of brake. The parties are entitled to the specific improvement they respectively invented, provided the later does not include the earlier.
3. Though the double brakes used before the Tanner brake was invented may have been much less perfect than it, and may have been superseded by it and by other improved forms of brake, nevertheless they were actually used, and to some good purpose. Their construction and use, though with limited success, were sufficient to contravene the pretension of Thompson and Bachelder that they were the pioneers in this department of invention.
4. The original application for a patent made by Thompson and Bachelder was filed in the Patent Office in June, 1847. Having been rejected, it remained there unaltered until 1852, when it was considerably amended, and letters patent No. 9109 were, July 6, 1852, granted thereon to Tanner, as assignee. Held that no material alterations introduced by such amendments could avail as against parties who had introduced other brakes prior thereto.
5. The original application for letters patent (with its accompanying drawings and model), filed by an inventor, should possess great weight in showing what his invention really was, especially where it remains unchanged for
a considerable period and is afterward amended so as to have a broader scope. Amendments embracing any material variation from the original chanroblesvirtualawlibrary
application -- anything new, not comprised in that -- cannot be sustained on the original application and should not be allowed; otherwise, great injustice might be done to others who may have invented or used the same things in the meantime.
6. The law does not permit enlargements of an original specification any more than it does where letters patent already granted are reissued. It regards with jealousy and disfavor any attempt to enlarge the scope of an application once filed or of letters patent once granted, the effect of which would be to enable the patentee to appropriate other inventions made prior to such alteration or improvements which have gone into public use.
The facts are stated in the opinion of the Court.