Origin of modern calculating machines

by J. A. V. Turck

The Second Felt Recorder

First practical arithmetical recorder

While the last-described Felt patent was still pending, Felt improved his mechanism for recording, installing new features and eliminating the objectionable features referred to. These improvements were of such a satisfactory nature that the Felt & Tarrant Mfg. Co. made twenty-five recording-adders, with the new features, which were sold to various banks. The first of these machines was placed on trial with the Merchants & Manufacturers National Bank of Pittsburgh, Pa., in December of 1889.

Good evidence of the practical features of this machine was set forth in a testimonial given at the time by W. A. Shaw, the cashier of the bank, after it had been given a six months’ test. This [testimonial] is extant and has been reproduced on opposite page.

The first sale of a recording-adding machine on record

Records show that the bank purchased that “Comptograph,” which was the trade name given the Felt recording-adder, and used it until 1899, at which time this machine, along with others of the same make purchased at a later date, were replaced by the bank with “Comptographs” of more modern type.

This Felt recording machine was without question the first practical recording-adding machine ever sold that would produce legible printed records of items and totals under the variable conditions that have to be met in such a class of recording.

Testimonial

Felt Recording and Listing Machine.

Purchased and Used for Ten Years by the
Merchants & Manufacturers Bank of Pittsburgh, Pa.

Machine is now in the National Museum at Washington

After ten years of service this first practical recording-adding machine was still in excellent condition, and in 1907 was secured by the Comptograph Co. from the Bank of Pittsburgh, into which the Merchants & Manufacturers National Bank, along with other banks, had been merged. It was finally procured by Mr. Felt and presented to the National Museum of Washington, D. C., where it may now be found on exhibit along with other inventions produced by Felt. A [photo reproduction of this machine] as it appeared before it was presented to the Museum, is shown on the opposite page.

Features of first practical recorder

Like the machine of the first Felt recorder patent, it was a visible printer, each figure being printed as the key was depressed, the paper being shifted by the hand lever shown at the right.

Unlike the former machine, however, the operator was not called upon to perform the extra operation of winding up a spring to furnish power for the printing.

Power for the printing was stored by the action of the paper shift-lever and an entirely different printing device was used. Provision for printing the ciphers automatically was also a feature of this machine. It was not necessary to operate cipher keys, and there were no such keys to be operated. To print an item having ciphers in it required only the omission of the ciphers as the ciphers would automatically fill in.

The arrangement of the paper shows a good improvement over the first machine, as it was more accessible, being fed from a roll at the top down and around rolls below and looped back so that it is moved upward on the printed surface, where it may be torn off as desired.

The mechanism of this machine is not illustrated in any one patent. The Felt patents Nos. 441,233 and 465,255 cover the new feature, but the later patent, No. 465,255, shows it best. Some of the drawings of the last-named patent are [reproduced on the opposite page] to help in explanation of the details of the new features.

Description of Felt’s second recorder

By referring to the [drawings], it will be noted that the form of the front of the casing differs from the machine. Other drawings of the patent, not shown here, disclose features of still later invention than were in the machine of the [photo reproduction]. But it is with the printing device that we are now interested, and it was in this patent that it was first shown in the form used in the first marketed machine referred to.

The type sector marked 81 is like that of the first patent, except that it is provided with the ciphers as well as the nine digits.

The cipher type are always presented for printing when the sectors are resting at normal. Thus, if an impression can be made without depressing the keys in that order, a cipher will be printed, as will be shown later.

Back of the paper and pivoted to the rod 97, are a series of printing hammers 87, one for each type sector.

The hammers are operated by the spring 88, and are shown retained against the tension of their springs by the trigger latches 89.

These trigger latches are pivoted on the fixed shaft 171ᵃ, and actuated by the springs 92 to cause their engagement with the notch 90 of the printing hammers.

From Drawings of Felt Patent No. 465,255

Each of the trigger latches are provided with a laterally extending lug 93, formed on their lower arm, and each lug overlaps the back of the lower arm of the adjacent trigger latch to the right of it, so that if any trigger latch should be operated so as to extricate it from the notch 50 of its printing hammer, its overlapping lug 93, would cause a like action of the trigger latch to the right of that, and so on; thus releasing all the trigger latches to the right of the latch originally released. Such releasing, of course, allowed the printing-hammers 87, to spring forward in all the orders so affected.

The long-stop actuating lever marked 16, corresponds with the lever G of the Felt key-driven calculator shown in a preceding chapter, and performs the same function as the rock bars L of the first Felt recorder patent. These stop levers 16 are pivoted at 17, and are provided with rear arms 86, extending upward with their ends opposite the lateral extending lug 93, of the trigger latch, which corresponds to the order of keys which the lever 16 serves.

In the rear upwardly-extending end of each of these levers 16, an adjusting screw 91, is provided as a tappet for tripping the trigger latch corresponding to its order.

From the above-described combination of mechanism, it may be seen that if a key in any order is depressed, it will, as it comes in contact with the stop lever 16, not only cause the adding mechanism to be stopped through the stop 19, but it will also, through its rear arm 86, cause the trigger latch of its order to trip, and likewise all the trigger latches and printing-hammers to the right, thus printing the figure presented on the printing sector in the order in which the key was operated and the ciphers in the orders to the right in case the keys in the order to the right have not previously been operated.

The individual presentation of the type figures upon key depression, except for the ciphers which were normally presented for printing, required that in striking the keys, to give correct recording of the items, the operation must be from right to left. That is, for example, if the item to be added was $740.85, the operator would depress the (5) key in the units cents column, the (8) key in the tens of cents column; the cipher in the units dollars column would be omitted, the (4) key in the tens of dollars, and the (7) key in the hundreds of dollars column would be struck.

The printing hammers were provided with means for resetting after being tripped in the recording action. This means is connected with the paper shift-lever, so that as the paper was shifted or fed upward, ready for recording the next item, the printing-hammers were all reset and latched on their respective trigger latches, ready for a new item.

Fixed to the shaft 97, on which the printing-hammers are pivoted, is a bail, marked 98, part of which is shown in the drawing, the horizontal bar of which normally lies under and out of the way of the hammers as they plunge forward in printing. And attached to the right-hand end of the shaft 97, is a crank arm connected by a link to the paper-shift hand-lever, which may be seen on the right in the [photo reproduction of the machine]. This connection is arranged so that depressing the lever causes the shaft 97 to rock the bail 98 rearward, thus picking up any tripped printing-hammers and relatching them.

The totals had to be printed, as in the first-described Felt recorder, by depressing a key corresponding in value to the figure showing on the wheel in each order.

Felt principle of printing adopted by all manufacturers of recorders

The principle involved in the individual hammer-blow, combined with the ordinal type sector for recording in a recording-adder was new, and was the feature that has made the adding-recording machine of today possible, as is well in evidence by the presence of this combination in all the recorders that have been made by the successful manufacturers of listing or recording-adding and calculating machines. Some manufacturers have substituted a vertical moving type bar for the pivoted sector, but the scheme is the same, as the purpose is to get the arrangement of the type in columnar order, and does not change the fundamental features of the combination which furnished the practical means for the individual type impression.