From Drawings of Felt Patent No. 405,024
Felt’s first recording machine
Some of the drawings of this patent will be found [reproduced on the opposite page], from which the reader will note that Felt combined his scheme for recording with the mechanism of the machine he was then manufacturing and selling under the trade name of “Comptometer.”
In this patent is shown the first application of the type sector combined with the individual type impression for printing the figures of the items as they were added, thus giving equal impression, whether there were one or a dozen figures in the item or total to be printed.
While the average mechanical engineer would not at a glance recognize any great advantage in placing the type figures directly on the sector instead of using the type-wheel and segment gear to drive it, as shown in two of the previously described patents, there is plenty of evidence of its advantage in the fact that all the later successful inventors have followed the Felt scheme. It provided more simple construction for the narrow space these parts must occupy for practical linear spacing.
Fell recording mechanism combined with his calculating machine
As the adding mechanism of this machine corresponds to that of the Felt patent 371,496, previously described in the preceding chapter, it is not necessary to duplicate the description here. Suffice it to say, that by the depression of a key in any order, the value of that key is added to the numeral wheel of that order, and if the figure added is great enough when added to that previously registered on the wheel, a ten will be transferred to the higher wheel by a carrying mechanism specially provided to allow the said higher wheel being in turn operated by an ordinal series of keys, thus providing the means whereby a series of denominational orders of key-driven adding mechanism may be interoperative.
Description of Felt’s first recorder
In [Fig. 2 of the drawings] is shown the result of striking the (8) key, which may be considered illustrative of such action in any order, whether units, tens, hundreds, thousands, etc.