(after stating the

facts as above). This litigation is between rival manufacturers of door checks or catches designed to hold a swinging door yieldingly closed. The sole question is that of infringement, the validity of plaintiffs’ patent being uncontested.

As indicated by the claims above quoted, the principle of operation of the patented device involves a pivoted crescent-shaped arm controlled by a spring, which, when the ar'm is in one position, exerts force to hold it closed against the door, and, when in another position, to snap it open. The bearing for the pivoted arm is central, that is, it is between the two side plates of the crescent-shaped arm; and it is offset, that is, the post, the end of which carries the bearing, is curved in gooseneck shape, so as to permit one end of the crescent-shaped arm to swing beneath the bearing and come up against the inner side of the post when the arm is closed.

Door cheeks operating on a similar general principle were old in the art. Five prior patents were introduced by the defendants, not to invalidate the patent in suit, but to limit the scope of its claims. The learned District Judge carefully and properly analyzed those prior patents, but reached the conclusion that they in no way affect the scope of the claims. With this conclusion we cannot agree. We think the case demands application of the principle stated in Boyd v. Janesville Hay-Tool Co., 158 U. S. 260, 261, 15 S. Ct. 837, 39 L. Ed. 973, where Mr. Justice Shiras said that, in view of the state of the art, the patentee was entitled only to the precise devices mentioned in his claims.

An essential feature in eaeh of the claims is an “offset central bearing.” The patentees state in their patent (page 2, line 58) :

“We desire to call especial attention to the form of the base A which makes it possible to have a central bearing 2 between the side plates 15 and 16 of the arm B and at the same time have a buffer 20 between the inner ends of said plates.”

We do not find such construction in the defendant’s device. Instead of a gooseneck *414post, centrally placed between the sides of the crescent-shaped arm, its base is á stationary outer box frame or easing, within which is pivoted a crescent-shaped arm, which swings inside, the box frame, and to which is connected one end of a helical spring; the other end being anchored to the box frame. It is much like the door cheek described in the Robinson & Deán patent, No. 911,074. It differs from that,, in that the crescent-shaped arm is made of one piece of metal, instead of two spaced plates riveted together, and in that the stationary end of the spring is of necessity anchored to the sides, instead of the back, of the box frame. The District Judge correctly said that the Robinson & Dean patent “contains no central bearing about which the erescent:shaped arms swing.” . No more, we think, does the defendants’ device. Nor is its bearing “offset” in any sense different from Robinson & Dean’s device, which was cited and discriminated in the application for plaintiffs’ patent. Both the prior art and the file wrapper and contents of plaintiffs’ patent so limit the term “offset central bearing” that it cannot be construed to cover a device like the defendants’, in which, in order to support the crescent-shaped arm, it is necessary to construct a box around it.

In claim No. 3 an essential element is a curbed link pivotally connected to the base below the central bearing and adapted to swing around the central' bearing. It also acts as a buffer to limit the backward swing of the arm, as explained in lines 30-40, page 2 of the patent. No such link is found in the defendants’ door catch, nor is the curved arm to which one end of the spring is attached a mechanical equivalent, for they operate in different ways and perform different functions.

There being no infringement, the decree is reversed, with costs, and the cause remanded, with directions to dismiss the bill. '