296 TEDERAL RBPOETEB. �Both parties use the pivot which attaches the shank to the beam; but this pivot is not claimed by the complainants as part of their invention. As, therefore, the construction of the defendants' device does not include the curved brace-bar, if the case were to stop here it would seem that the patentees' entire conabination is not appropriated, and so that there is no infringement. But it is insisted that the difference be- tween the two devices is ore merely of form, and that in fact ail the elements of the complainants' machine are present in that which the defendants are selling. There is no doubt of the right of a patentee to invoke the doctrine of equivalents on a question of infringment in the case of a combination patent. The law upon this subject is settled in Conner v. Roach, 4 Fish. 12; Seymoiir y, Osborne, 11 Wall. 516; and in Gould V. Rees, 15 Wall. 187. In the case of Seymour v. Oshorne the court say that "mere formai alterations in a combination • * * are no defence to the charge of in- fringement, and the withdrawal of one ingredient from the same, and the substitution of another which was well kuown at the date of the patent as a proper substitute for the one withdrawn, is a mere formai alteration of the combination, if the ingredient substituted performs substantially the same function as the one wifhdrawn." But the court further say that to constitute infringement ail the material ingredients of the prior combination must be appropriated, and that the inventera of a combination "cannot suppress subsequent im- provements which are substantially different, whether the new improvements consist in a new combination of the same in- gredients, or of the substitution of some newly-discovered ingredient, or of some old one performing some new function not known at the date of the letters patent as a proper sub- stitute for the ingredient withdrawn." And in Gould v. Rees the court say: "Bonajide inventors of a combination are as much entitled to equivalents as the inventors of other pat- entable improvements. * * * Apply that rule and it is clear that an alteration in a patented combination which merely substitutes another old ingredient for one of the in- gredients in the patented combination, is an infringement of ��� �
