Origin of modern calculating machines

by J. A. V. Turck

From this single lever action it will be noted that there is an improvement shown over and above the Pottin invention in the fact that but one lever motion is required; Pottin having provided two levers so that in the event of error the operation of one lever would reset the machine without performing any addition or printing.

In the Burroughs invention, the motion of denominational actuators and their type-wheels not being effected through depression of keys, as in the Pottin machine, allowed any error in the setting up of an item to be corrected by the resetting of the keys and relatching of the gears, which it is claimed was provided for by operation of the lever marked B⁷ ([Fig. 1 of the drawings]).

As a means of supplying power to his denominational actuators, Burroughs provided what may be called a universal actuator common to all orders, composed of a rock-frame (arms D², loose on each end of actuating shaft C, and having their outward ends rigidly connected by the bar a⁹) and the arms E, fixed to each end of the shaft C.

Projecting from the inside of each of the arms E, are two lugs, b¹ and b³, which contact with the arms D² of the rock-frame as the shaft C is rocked back and forth by its hand crank C⁵, and thus lower and raise the rock-frame.

The means employed to transmit the reciprocating action of the universal actuator to such denominational actuators as may be unlatched by key depression, consists of a series of spring-pressed arc-shaped levers D¹, pivoted to the rock-frame bar a⁹, which bear against a pin b² fixed in the front arm of the denominational actuators.

Each of the levers D¹, is provided with a notch y, which serves on the downward action of the rock-frame to engage the pins b², of the denominational actuators and draw down with them such actuators as have been unlatched by key depression and to pass over the pins of such actuators as have not been unlatched.

When in the course of such downward movement the denominational actuators are intercepted by the stop-wires C¹, the yielding spring pressure of the levers D¹, allow the notches y, to slip over the pins b², and leave the denominational actuators and their type-wheels set for recording the item thus set up.

The means provided for impression of the type is shown in other drawings of a patent not reproduced here. The means provided consisted of a universal platen, which, the specification states, serves to press the ink-ribbon and paper against the type after all the figures of each item were set.

While Barbour, Baldwin and Pottin all used the universal platen to print the collective setting of type represented in the items or totals, as the case may be, each varied somewhat in detail. Baldwin used a toggle to press the platen toward the type, while Burroughs used a spring to press the platen against the type and a toggle to press it away from the type.

Burroughs claimed to have combined in his invention the printing of the totals, with the printing of the items, each of which it has been shown was claimed by the patentees of previous inventions but had not been combined in one machine prior to the Burroughs attempt.