Page:Federal Reporter, 1st Series, Volume 9.djvu/925

 '910 FEDERAL REPORTER. �structed that the thrust or back-strain of the rosette screw, wlien the wrench is used, shall be borne by the shank instead of the handle of the wrench, substantially as described." Mr. Waters, an expert for the plaintifi, testifies that the defendant's wrench is, in his judgment, the same in its construction and mode of operation as the wrench described in the reissue and referred to in the first elaim, because the essential novelty of the wrench described in the reissue consists in a mode of construction to relieve the Coes wrench of the diffioulty described in the reissue ; that this is done in the reissue by bringing the back-thrust to bear against projections on the main bar, running across it, against which the rosettes on the screw act ; that in the defendant's wrench the end-thrust is taken on the plate, and then, through the screw nut, cornes on the shank by means of the threads inside of the screw nut and the threads on the shank, which bear against the former threads ; and that this is only an equivalent for the projections on the main bar, in the reissue, against which the rosettes bear. Another of the plaintiff's experts, Mr. E. S. Eenwick, states that the two wrenches obtain by substantially the same means , the resuit of sustaining the strain of the movable jaw and of the rosette screw by the shank or bar of the wrench, in thie': that in the defendant's wrench the rosette and the screw are combined with the rectangular part of the shank, or its equivalent, by a notch, which limits the movement of the rosette and screw in both directions, with- out the intervention of the handle, the notch having its upper shoul- der formed by a portion of the rectangular shank itself, and its lower shoulder formed by the upper surface of the plate, whieh plate is rigidly secured to the shank ; and that holding the lower shoulder of the notch to the shank by the screw nut in the defendant's wrench is a well-known substitute for the Taft method of holding the lower shoulders of the grooves to the shank by the substance of the ma- terial of which they are composed. �It is entirely clear, as is testified to by Mr. H. B. Renwick, the defendant's expert, that if, in the Coes wrench of 1841, the back- thrust of the screw reaches the plate it is transmitted through it and the wooden handle, and the nut at the end of the shank, which is an extension of the main bar, to the shank, so that it is borne by the shank. It cornes back thus to the column formed of the main bar and shank as one piece. If the plate bends, or the ferrale is dis- placed, or the wooden handle is broken, those are incidents of the pressure, and those incidents happen only because the thrusfc is being ��� �