US1406712A - Adding and subtracting device - Google Patents

Description

A. WOLPERT. ADDING AND SUBTRACTING DEVICE.

APPLICATION FILED DEC. 27, I920- Patented Feb 14 19220.

UNITED STATES ALBERT WOLPERT, 0F PITTSBURGH, PENNSYLV ANIA.

Specification of Letters Patent.

ADDING AND SUIBTRACTING DEVICE.

Patented Feb. 14, 1922.

Application filed December 27, 1920. Serial No. 433,145.

To all whom it may concern:

citizen of the United States,'residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Adding and Subtracting Devices, of which the following is a specification.

This invention relates to adding and subtracting machines, and more particularly to such machines of the type called vest pocket size.

One of the main objects is to provide a device especially adapted for adding or subtracting inches and fractional parts thereof. Another object is to provide such a device of very reduced volume and easy operation. A further object is to provide a machine of very simple and cheap manufacture. Further objects and advantages will appear from the detailed description and the drawings forming a part of this application.

In the drawings:

Fig. 1 is a front elevation showing the distinctive features of my invention.

Fig. 2 is a cross-sectional View taken.

along the line 2-2 in Fig. 1. 1

Fig. 3 shows a modified graduation used on my invention.

Referring more in detail to Figs 1 and 2, my invention consists of the stationary graduated disc 1 centrally perforated to receive the cylindrical brass sleeve or eyelet 2 upon which are rotatably and centrally mounted the discs 3 and 4 situated respectively at the front and the rear of the main disc. Suitable spacing washers 5 and 6 are inserted betweenthe discs to reduce the frictional wear and insure proper rotation of the outer discs.

A hand 7 is rotatably mounted on the eyelet 2 outwardly of the disc 3 and is separated therefrom by the small washer 8. This hand is provided with the securely mounted grip-knob 9 and the pin 10 directed inwardly of the hand to engage the holes 11 spaced uniformly and circumferentially on the disc 3.v

As shown in Fig. 2, the ends of the eyelet 2 are turned over to provide flanges 12 for retaining the outer discs 3 and 4.

In Fig. 1 I have shown my adding machine adapted for adding inches and fractions thereof, down to one-sixty-fourths. With this end in view, the circumference of the main disc 1 is-evenly divided into 64 parts separated by the radial lines 13. The Be it known that I, ALBERT WOLPERT, a

annular space situated between the main disc and the rotating disc 3 is divided into three rings by the two concentric circles 14 and 15 which, in conjunction with the radial lines 13, divide this space into the ringsectors 16 designed to contain the various figures. Referring to Fig. 1, it will be noted tha in the outer ring I indicate the numerators and in the middle ring the denominators of the fractions. The graduation in the outer ring is made in clock-wise direction, the variation between each division being one sixty-fourth, and all fractions being reduced to their smallest denominator. The graduation in the inner ring refers also to the numerators, but it is run in the opposite direction to that shown in the outer ring. Due to this arrangement, it will be observed that the figures in the outer ring form the complement of those indicated in the inner ring, that is, the sum of the outer and inner figures for a given division will e ual the denominational number shown in t e middle sector.

To facilitate the reading of the graduations, I generally accentuate the division lines enclosing'the fractions most in use, as shown in Figure 1 for the fractions one quarter, one half, three quarters and the unit. Also, I provide on the rotating disc 3 the triangular arrow-point 17 which serves as an indicator or starting indicia for the operation of my device.

The operation of my device is very simple and can best be illustrated by the succeeding examples.

To add the following fractions of an inch: 1/4, 7/16, 9/32, and 15/64", proceed in this manner:

Place the arrow-point 17 at 0; turn hand 7 counter-clock-wise and place the pin 10 into the hole in the disc 3 opposite to 1/4 in the inner rings; turn hand 7 and disc 3 clockwise into the position opposite to 0 and repeat the same operations for the other fractions. The total sum will be one and thirteen sixty fourths;the fraction being read in the outer rings and the digit being obtained by counting the number of times the arrow-point 17 passes the zero point.

For the pur ose of expediting the setting of the hand into the zero position, the stationary disc 1 is provided at this point with a hole, coinciding with the perforations 11 in the disc 3, which acts as a stop for the pin 10.

To subtract 25/64: and 13/32 from 1",

for example, set arrow-point 17 at zero, turn hand counter-clock-wise into the hole opposite to 25/64", inner rings, and move the rings.

In Figure 3 I have shown an adaptation of my device for use with whole numbers, up to one hundred. As will be seen, the graduation in the outer and inner rings run in opposite directions and the intermediate ring is left blank since it is only intended for denominators.

The operations for this modifiedform of my invention are carried in an analogous manner as described for the fractions and need therefore not be explained again.

To increase the usefulness of my invention, I avail myself of the empty spaces to print valuable information for the various trades. Thus, for example, I provide in the disc 3, Figure 1, an opening 18, which enables the user of my device to obtain the decimal equivalent of any given fraction by turning the disc until the arrow points to said fraction and reading the equivalent, printed on the stationary disc and beneath the rotating disc, as indicated by the ,cut 19, through the opening 18.

The object of the rotating disc 4, is to provide further such information as may be valuable for the various trades for which my device may be made purposely.

If desired, my adding machine may be arranged for fractional and whole numbers by placing on one side of the stationary disc the graduations shown on Figure 1 and on the other side the graduations and rotating disc shown in Figure 3 and supplying each side with a hand 7.

It may be found desirable in practice to resort to slight changes in construction and arrangement of the details of my invention without departing from the field and scope of the same, and I intend to include all such variations, as fall within the scope of the appended claim, in application in which the preferred forms only of my invention are disclosed.

What I claim is:

In a device for adding inches and fractions thereof, the combination of astationary' disc; a second disc of lesser diameter centrally and rotatably mounted thereon; the annular space provided between the peripheries of said discs being divided into three concentric spaces and circumferentially into as many ring-sectors as correspond to the denominator of the smallestfraction of an inch for which the device can be used; the ring-sectors in the outer and inner rings bearing the numerators of the various fractions; the numerators in the outer ring progressing arit-hmetically in opposite direction to those of the inner ring; the ring-sectors of the intermediate ring bearing the denominator of the fractions;

a plurality of apertures provided circum- 7b ferentially on said rotatable disc; said apertures corresponding in number and radial alignment with the ring-sectors; a hand rotatably mounted on the common center of said disc; said hand being provided with a pin securely mounted thereon for selective engagement with the circumferentially disposed apertures provided in said rotatable disc.

In testimony whereof I afiix my signature.

ALBERT WOLPERT.

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