Henry Billings Brown

“ To answer satisfactorily the question of infringement, it is necessary to refer to the state of the art, and to distinguish that which was already well known at the date of this patent, from that which Ritty and Birch contributed by their invention. While the novelty of their device is not directly attacked, it is claimed that, in view of certain prior patents, their patent is subject to limitations which affect materially the construction of the first claim, and show defendant's machine not to be an infringement. ”

“ When the key is again depressed, another tablet rod rises, but before its shoulder has passed the co-operating latch the first tablet falls upon the latch, which gives way to allow the rod to fall, when the last rod rises and remains exposed to view. These latches are weighted in such manner as to remain in place as the rod rises, but to give way when it is desired that the rod shall fall. The device is an ingenious one, but is chiefly valuable in this connection as showing that, prior to the Ritty and Birch patent, the sliding bar was well known as an equivalent for the pivoted wing. ”

“ To secure a more perfect operation of this wing, a bar, K, is extended across and directly underneath the front ends of the keys, so that whenever any key is depressed this bar is also depressed. Connected with this bar is a train of mechanism, which appears in the drawing and is described in the specification, but which is not necessary to be set out here in full. This mechanism operates directly upon the wing, I, and secures beyond peradventure the falling of the tablet, before the elbow of the next tablet rod has passed the upper edge of the wing. ”