Cash Register 2
The trouble was that the knuckles, being necessarily oiled, held dust and dirt which interfered with their free movement. And again, a "five-cent" or "ten-cent" key would be used more than others, and hence would become more worn. As a practical result the tablets did not drop when wanted, and the whole operation was thrown into confusion. When one tablet went up the other tablet stayed up, leaving a false indication. The most valuable modification now made by these Dayton inventors was to cease to rely on the knuckle to move back the supporting bar, and to supply the place of this function by what became known as "connecting mechanism," especially designed for this purpose. This was placed at the other, or say the left, side of the machine as you faced it. Cut No. 2 shows this new connecting mechanism. The keys, when pressed, performed the functions as before, on the right side of the machine, viz. to ring an alarm-bell, etc.; but on the other, or left, side the key, when pressed, operated the connecting mechanism marked M, N, O, P, and Q. The key pressed down by its leverage pushed back a little lever (Q), the further end of which pressed back the supporting bar F, and released the previously exposed indicator G, without relying on the knuckle to perform this function.
Cash Register
The origin of the cash register is rather nebulous, because twenty-five years ago several men were working on the same idea. It first appeared as a practical machine in the offices of John and James Ritty, who owned stores and coalmines at Dayton, Ohio. James Ritty helped and largely paid for the first experiments. He needed a mechanical cashier for his own business, and says that, while on an ocean steamer en route to London the revolving machinery gave him the suggestion worked out, on his return to Dayton, in the first dial-machine. This gave way to the key-machine with its display tablet, or indicator, held up by a supporting bar moved back by knuckles on the vertical tablet rod. The cut shows the right side of this key register, the action of which is thus described by the National Cash Register Company. The key A, when pressed with the finger at its ordinary position—marked 1—went down to the point marked 2. Being a lever and pivoted to its centre, pressing down a key elevated its extreme point B. This pushed up the tablet-rod C, having on its upper part the knuckle D. This knuckle D, pushed up, took the position at E; that is, the knuckle pushed back the supporting-bar F, and was pushed past it and held above it. If the same operation were performed on another key, the knuckle on its vertical rod, going up, would again push the supporting bar back, which would release the first knuckled rod, and leave the last one in its place. This knuckled rod had on its upper end the display tablet, or indicator G