Ashcroft v. Boston & L. R.

2 F. Cas. 20, 1 Holmes 366
U.S. Circuit Court for the District of Massachusetts·Decided May 15, 1874·Published·Cited by 2 cases

Opinion

SHEPLEY, Circuit Judge.

The bill in this case charges the defendant with infringement of letters-patent of the United States, reissued Nov. 9, 1869, [No. 58,962,] to the complainant, as assignee of William Naylor, of the county of Middlesex, England, for an improvement in steam safety-valves. The answer of the defendant sets up in defence: First, that the reissued letters-patent are not for the same invention described in the original letters-patent. Second, that William Naylor was not the original and first inventor of the improvements specified in said reissued patent, but that the same were known to others and used by them, as stated specifically in the answer, prior to the alleged invention thereof by Naylor. Third, that the reissued patent does not cover and embrace the valve used by the defendant. Fourth, that the valve used by defendant is described and contained in letters-patent of prior date to complainant’s invention, granted by the British government to Thomas Green, also to Charles Beyers, and by the United States to Henry Waterman, and also to George W. Richardson, and that the invention of George W. Richardson, described in his patent, was made prior to the invention of Naylor set out in the bill. The invention relates to spring safety-valves for use on locomotive, stationary, and marine engine boilers. As the spring on common safety-valves was compressed by the lifting of the valve, the force of the spring became stronger by tension, while, inversely, from other causes, the tendency of the valve to rise became weaker. The spring safety-valve, therefore, failed to relieve the boiler; for, as the spring was compressed by the lifting of the valve, its power to resist was largely increased, and if steam was rapidly generated, the pressure in the boiler continued to increase while steam was escaping at the valve. Various attempts have been made, as shown by the various patents in evidence, to obviate this defect in the operation of the common spring safety-valve.

William Naylor, in his specification filed in the great seal patent office of Great Britain, on the twenty-first day of January, 1864, described two methods of obviating this difficulty. One of these methods claimed by him as his invention, he says, “consists, when using a spring for resisting the valve from opening, in the employment of a lever of the' first order, one end resting by a suitable pin upon the safety-valve, and the other end of the lever resting upon the spring being bent downward to an angle of about forty-five degrees from the iuicrum, so that, when the valve is raised by the steam, the other end of the lever is depressed upon the spring downward, and at the same time is moved inward toward the fulcrum, thus virtually shortening that end of the lever, and thereby counteracting the additional load upon the valve as it is raised from its seat by the greater amount of compression put upon the spring.” This method he claimed as his invention in the specifications of his English patent. These specifications also described another method of obviating the difficulty. This consisted of the following contrivance: A lateral branch or escape-passage was provided for a portion of the steam after it passed the valve, the valve was made to project over the edges of the exit-passage for the steam, and the projecting edges of the valve were curved slightly downward, so that the steam, on issuing between the valve and its seat, would impinge against the curved projecting portion of the valve, and a portion of it would be directed downward into the annular chamber which surrounded the central passage for the steam, which chamber communicated with the exit-pipe, while the other portion of the steam ascended past the edges of the valve. “By this [21] means,” he states, “I am enabled to avail myself of the recoil action of the steam against the valve, for the purpose of facilitating the further lifting of such valve when once opened; but I wish it to be understood that I lay no claim to such recoil action, nor to the extension of the valve laterally beyond its seat.” And in the claims, at the close of his specifications, he made no claim for any such extension of the valve, or any device for effecting any recoil action of the steam. In fact, Charles Beyer, in his English patent, dated Oct. 21, 1863, before the date of Naylor’s patent, had fully described a valve made to project over the edges of the exit-passage for the steam, and the projecting edges of the valve were curved slightly downward, so that the steam, on issuing between the valve and its seat, would impinge against the curved projecting portion of the valve. The description is as follows: “This invention consists in forming a flange round the valve, commencing at the outer edge of the valve-facing, which flange is undercut and concave in shape, and the concave side is toward the seating of the valve, which has also a flange upon it, commencing at the outer edge of the valve-seating, but the upper surface of the flange is convex, and corresponds nearly to the concave surface of the flange upon the valve. There is a slight space between the concave and convex surfaces of the two flanges, which diminishes toward the outer edge of the flanges. When the steam begins to escape from between the surfaces of the valve, it gets between the concave and convex surfaces of the two flanges, and its force thus acts upon a larger area, and reacts upon the concave surface of the valve, and causes it to open to a greater extent than the ordinary safety-valve.” It will be seen from this description that the Beyers safety-valve had “an overhanging ■downward-curved lip or periphery and an annular recess,” into which the steam will be directed downward on issuing between the valve and its seat, while a portion of the steam will also impinge against the curved projecting portion of the valve.

Free access — add to your briefcase to read the full text and ask questions with AI

Ashcroft v. Boston & L. R., 2 F. Cas. 20, 1 Holmes 366 (circtdma 1874).

2 F. Cas. 20 (Ashcroft v. Boston & L. R.) — published by Counsel Stack Legal Research, free access to 12M+ legal documents.

Related

Consolidated Safety-Valve Co. v. Crosby Steam-Gauge & Valve Co.
7 F. 768 (U.S. Circuit Court for the District of Massachusetts, 1881)