shoulder B, with flange 0, stem a, and spring b, all as and for the, purpose set forth." The plaintiffs endeavor to have the claim construed .to mean the combination of screw socket, a sliding bolt provided with a thumb pad and stem, and the spring, so that sliding bolt, if provided with a thumb pad and a stem or leg of any sort, would be included within the patent. This is not the obvious meaning or the claim or' of the specification. The specification describes the stem with more particularity than the patentee used in regard to the other parts of the combination. Indeed, but little description of the elements of the device was necessary or was given, as the different parts were well known, and were clearly shown in the drawings. The patentee intended to claim the combination of screw socket, sliding shoulder with flange, stem a, (the last two elements constituting a well-known form of bolt,) and the spring. The stem is made, in the patent, as important a member of the combination as any other. This combination was novel and useful. It is admitted that the defendants have infringed the patent by the manufacture and. sale of articles like Exhibit 4, which arE' the plaintiff's catch with a double stem. The defendants have aiso made and sold articles which were known upon the trial as Exhibit 5. The question in the case is whether the' form of sash-holder is an infringement. The catch consists of a cylindrical screw socket, the bottom of the socket having no hole. The bolt has the plaintiff's sliding shoulder and thumb pad, but the defendants have, with a gooa deal of ingenuity, made a somewhat clumsy new hub or stem in place of stem A. Instead of the slender, round stem, whose diameter is no larger than the thickness of the shoulder, the diameter of the defendants' hub is greater than the thickness of the bottom of the bolt, whereby two shoulders are formed at the junction of the body and hub, which shoulders enlarge the bolt at that point so that movement outward or toward the window is limited. The hub has a socket, to receive the spring, and its inner end has four radial arms or prongs, which extend outward far enough to span substa.n-
tially the inner chamber of the socket. These arms bear upon the inner walls of the socket; the shoulders at tho other end of the hub bear dso upon the side walls, 80 that the bolt is supported at each end, and is moved endwise with the case on these supports. The bottom of the shell forms an abutment to the spring, as in the plaintiff's catch. The enlarged shoulders and radical arms prevent the bait from being inserted in the case through its outer end. The case is left open at the inner end and the bolt is there inserted, the arm, upon which is the thumb pad, being bent over so as to bring its outer end substantially in front of the opposite end of the bolt. After the thumb pad has passed through the orifice in the outer end of the case, the bolt is turned one-quarter revolution, and is also passed through the orifice until it is stopped by the shoulders. The spring is then placed in the socket of the hub and the bottom of the case is placed in position. This form of bolt was new a.t the date of the Babcock patent. It is not the Converse bolt, known as Exhibit 9, which, although it has the spring receiving socket in the hub, is differently constructed with respect to the sides of the hub, and to the position of the sliding shoulder. Had the defendants' bolt been known at the date of the patent, the general functions of the two bolts being the same, the substitution would have been simply a substitution of one well-known bolt for another, which performed the same office, and the change would have been formal. But the stem of the bolt is new, and while the general locking function of the two bolts is the same, the change in the method of construction is not merely formal, but is a change in the principle upon which the stem is made. The plaintiff's stem had its bearing in the hole in the bottom of the case. This compelled the stem to protrude through the bottom of the case when the bolt was pressed inwards. The defendants' stem has its bearings entirely upon the walls of the case, which .therefore is wholly closed except in front. Whether this is an advantage or not, I do not know. In consequence of the bolts coming in direct contact with the bottom of t',e CaEIt
les8 pressure may be brought to bear upon the spring than upon the plaintiff's, and it may be less liable to injury. The law upon the $ubject of equivalents for one of the members of a combination of old ingredients has been frequently laid down of late by the supreme court. It is stated in Gill v. Wells, 22 Wall. 1, as follows: "By an equivalent in such a case it is meant that the ingredient substituted for the one withdrawn performs the same function as the other, and that it was well known, at the date of the patent securing the invention, as a proper substitute for the one omitted in the patented combination. Hence it follows that a party who merely substitutes another old ingredient for one of the ingredients of a patented combination is an infringer, if the substitute performs the same function as the ingredient for which it was substituted, and was well known at the date of the patent as a proper substitute for the missing ingredient. But the rule is otherwise if the ingredient substituted was a new' one, or performed substantially a different function, or was not known at the date of the plaintiff's patent as a proper substitute for the one omitted, as in that event he does not infringe. " There must be a decree for an injunction, and for an accounting in regard to all artioles made like Exhibit 4:, with
TilE THATCHER HEATING COMPANY
(C'f,rcuit Court, 8. D. New YPrk.
PATEN'r-IMPRoVEMENT8 IN AIR-HEATING
SPEAR and another.
.January 28, 1880.)
Infringement of Patent. B. F. Lee, for plaintiff. E. Cowen, for defenda.nts. BLATCHFORD, J. Thii suit is founded on letters patent No. 71,244. granted to John M. Thatcher, November 19, 1867, for an "air-heating furnace." The specification states thai
the invention is one of "improvements ill lir-heating furnaces." The right figures in the drawings are all of them views of different parts of a fnrnace. The specification says: "My said invention consists of several improvements in hotair furnaces designed to be set in brick-work or inclosed in any suitable manner." The specification then divides the invention into six parts. The first part consists of one particular; the second part of three particulars; the third part of one particular; the fourth part of two particulars; the fifth part of one particular; and the sixth part of one particular. There are as many claims as there are particnlars, namely, nine. Only the second and third claims are involved in this suit. They relate to particulars 1 and 2 of the second part of the invention. The text of the specification says, in respect to those par"My invention also consists in the combination and arrangement of a passage way from and through the furnace rront to and into the fire-pot at the bottom thereof, the passage way being of sufficient width and height to admit of the intrJduction of a slicer or poker for the purpose of slicing the fire and removing the clinkers from the grate-bars forward; the bottom of the passage way being on a line with the top sm face of the grate bars, and the top and sides of the passage way being formed by an enclosing plate, extending from the fire-pot to the furnace front, and joining at the sides the ash pit box, so as to prevent any commlinication between said passage way leading from the furnace front into the fire-pot and the hot-air chamber surrounding the fire-pot; and this part of my invention further consists in combining with said enclosed passage from the furnace front to the fire-pot a down ward opening between the furnace front and fire-pot, leading from said enclosed passage to the ash pit, whereby clillkers and other matter removed from the fire-pot may fall into the ash pit." The specification also says: "The drawings illustrate a furnace for brick-work, in which my inventions are embodied. The fire-pot a is a cylindrical casting, such 11>1 commonly used for that purpose, and sets upon a also of cast-iron, which