US814488A - Computing device - Google Patents

Description

. UNITED STATES PATENT torsion.

specincation of Letters Patent.

Patented March 6, 1906.

Application llod Augnlt 18, 1905.` Serial No. 274,691.

To all whom it may concern:

' Be it known that' I, WILLIAM H. WATSON, a citizenof the United States, residing at Danvers, county of Essex, State of Massachusetts,

- -have invented a certain new and useful Im.

- provement in ComputingDevices, of which the following is a specification,

reference being had therein to the accompanying draws. miltly invention hasfor its object to rovide a convenient device by means of whic averaes and proportions may be computed rapand Without figurlng.

Ihe device is especiallyr adaptedl for use where it is desired to strike an, average between two numbers or where it is desired to find the avera e .between two numbers one of which `is to e given a greater weight than the other-as, for instance, where a teacher has to compute a scholars marks and desires to give the mark on the daily recitations three times the weight which it is desired to giveto the mark obtained by the pu il upon the examination. If, for instance, t e pupil has obtained a` mark for the recitations of 84 and a mark for the examination of 96 and it is desired to give recitations three times the Weight of theexamination it is found that the desired average is 87.

B,whic

M invention will be fully understood from the ollowing'description, taken in connection with the accom .anying drawings, and the novel features t ereof are pointed out andv clearly defined in the claims at the close of this s ecification.

Re erring now to the drawings, Figure lis a plan view of a device embodyi my invention. Fig. 2 is a side elevation t ereof. Fig. 3 is a plan view of the fixed card. Fig. 4 is a plan view of the movable card.

Referring now to the drawings, at A is rindicated a card, which for convenience I have called thefixed card, and which may be made of any convenient substance-as, for instance, cardboard or celluloid. U on this card is ivoted at its center a movalile card li is circular in shape and is somewhat smaller than the fixed card A. It is necessa that the cards A and B be movable each wit relation to the other; but I have designated them by the terms fixed and movable to distinguish them. The movable -card B is provided with a handle C, by means of which It may be rotated about the central pivot D. Slots E, F, Gr, and H are cut in the said movable card B'to ermit the user to see certain figures on the ed card, as Awill be later described.

In the drawings I have shown Iny device as adapted especially for use in averaging percentages, and as the percentages below thirty are ordinarily neghrihle in the work. for which my computing evice `is intended and as the comparative weights to be given to the numbers to -be averaged are usually one toone, one to two, one to three', and one to four I have shown in thedrawings a computing device ada ted for this particular work; but it isto e understood, of course, that the invention may be embodied in other forms arranged for use where other propere tions or sets of numbers are required.

Upon 'the fixed card A and at a distance from its center about equal to the radius of the movable card B, I divide a convenient arc of a circle into equal spaces, numbered from 30 to 100, as indicated at I. For convenience I have denominated this are the greater-weight Scale.

The circumference of the movable card B is similarly divided into arcs, which I denominate the lesser-weight Scales. Each of these scales, which are indicated by the lreference characters J, K,' L, and M, are divided into equal spaces numbered from thirty to one hundred, in the same manner as has been described in connection with the geater-Weight scale I on the fixed card A. he lesser-weight scales have a length proportionate to the length of the greaterweight scale and to the relative Weights to 'be given to the numbers to be averaged. 'lhus the scale K is one-half the length of the scale J, the numbers to be averaged by the use of this scale being give-n the comparative weight of one to two. The length of the lesserweight Scale L is one-thir the length of the mater-weight scale I, and the length lof the esser-weig t Scale M is one-fourth ofl the len rth of the greater-weight scale I, thesesca es being used for yproportions of one to three and, one to four. By choosing a right length for the are occupied by the scale I and using the proportions mentioned the lengths of the four lesser-weight scales occupy the entire circumference ofthe .movable card B. It will thus be seen that the arc occupied bv the scales J, K, L, and M contains, respectively, one hundred and seventy-two and fourif the, 'eighty-six and two-fifths, fiftyseven and IOO so long as t three-fifths, and forty-three and one-iifthdegrees.

Concentric with the greater-weight scale I and nearer to the center of the iixed cardA are arranged what I denominate resultscales, one for each of the different proportions on the basis of which the averages are to be computed. These result-scales are indicated by the reference characters N, O, P, and Q, res ectively, and correspond to the lesser-wei t scales J, K, L, and M, respectively. liach of these result-scales has a length in de rees equal to the length of the reater-Weigt scale plus the length of the esser-weight scale to which the result-scale corresponds. Thus the result-scale N has a length equal to the length of the greater- Weight scale I plus the length of the lesserweight scale K, to which the result-scaleV N corresponds, and the result-scale Q has a length e ual to the greater-wei ht scale I plus the ength of the lesser-weig t scale M, to which the result-scale Q corres onds.

The result-scales N, O, P, an Q are located at radial distances from the centen of the iixed card A equal to the radial distances of the holes or slots E, F, G, and H, so that when the movable card B is revolved about its'pivot certain of thefi ures and divisionlines of the sets of scales O, P, and Q appear and are visible through their respective slots E, F, G, and H. I provide each of the said slots or holes E, F, G, and H with indicating marks or pointers R, S, T, and U, re-' spectively, each of the said pointers being located in the middle of the lesser-weight scale to which it ap lies.

I find it convenient to locate the resultscales symmetricall of the median line 4 4 of the greater-Weig t scale and to place the ointers on the movable card on the median ines of the arcs of the lesser-weight scales to which their7 apply; but this is not necessary e pointer on the movable card bears the same relation to the position of the lesser-Weightfscale as the result-scale does to the position ofthe greater-weight scale.

It is to be noted that fthe divisions'.y on the fixed card A from thirt to one hundred are numbered clockwise, W 'le the divisions on the movable card B are numbered counterclockwise. It is further to be noted that in this s eciiication I have referred to the lengt of the various scalesfi By this is to be understood the len th measured in degrees without regard to t e radius of the are which forms the scale referred to.

Having now described the manner in which I la out my improved computing device, I wil explain the mode of operation by means of WhichI am able to obtain the averages and proportions.

Let it be su posedthat'it is desired toobtain the simp e average of the two numbers 84 and 96. The division-line indicating'the number "84 on the lesser-weight scale J of the movable card B is placed to coincide with the division-line corresponding to the number 96 on the greater-weight scale I on the fixed card. The pointer R will then be seen to point to the division-line corresponding to the number 90 of the resultscale N, this ii ure being seen throu h the slot or aperture corresponding to theesser- Weight scale which is used-viz., that marked l to 1. If it is desired that the number 96 be given twice the Weight of the number 84, the scale K is used instead of the scale J, the division-line marked 84 on that scale being placed in registration with the divisionline corres ondin to 96 on the greaterweight sca e-I. he readin is then made by means of the pointer S, which is provided for the lesser-weight scale K. The desired result, 92, may be seen through the slot F. In the same manner other-averages may be obtained.

A general rule for the operation of my improved averaging device may be stated as ollows: Find the number to be 'ven the least weight on the lesser-weight sca emarked with the proportion desired, turn the movable card until the number found coincides with the division-line of the greater-Weightv scale on the fixed card corres ondi to the other number. Then read t e num er indicated by the pointer for the lesser-weight scale HWhere the first number was found.

Whena simple'avera e isto be found, either number may be foun on the fixed card or' on IOO suit-scale havin alength equal to that of.v

the greater-weig t scale plus the length `of a` lesser-weight scale, a lesser-weightscale on the said movable card having a length proportionate to the length of the greater-Weight scale and the relative weight to be given to the two numbers tobe averaged, anda pointer for the said lesser-weight scale to indicate divisions of said result-scale.

2. In a computing device of the character described the combination with a fixed and movable card of a eater-we' ht scale and-a series of result-sca es on the ed card, the said result-scales having a length e ual to that of the said greaterweight scale p us the len th 'of a corresponding lesser-weight sca e, lesser-weight scales on the said movable card having lengths proportionate to the length of the said greater-weight scale and the relative weights to be given the two numbers to be averaged, and a ointer for each ofthe said lesser-weight sca es.

3. In a computing device of the character described, 'the combination with a fixed and lne movable card, of a reater-wei ht scale and a series of result-sca es on the ed card, the said result-scales having a length e ual to that of the said greater-weight scale us the length of a corres onding lesser-weig t scale, lesser-weight scaies arranged aboutthe eir-l cumference-of the said movable cardhaving len ths proportionate to the length of the saifI4 greater-weight scale and the relative Weights to be given to the numbers t'o b e averaged and a ointer on the median line of each of the said esser-Weight scales.

4. In a computing device'of the character described, the combination with a fixed V,and a movable card, of a greater-weight scale and result-scales arranged on the fixed card conccntricall with relation to. each other, the said resu t-scales havin a length equal to that of the greater-Welght scale lus the length of a correspondin lesser-Weig t scale, a lesser-weight scale on te said movable card having a length proportionate to the len th of the greater-weight scale and the relative Weight to be given to the two numbers to be scale are visible, and 4a divislons ofsald result-sca es. v

avera ed, and a ointer to indicate divisions of sai result-sca es.

5. In a computing device of the character described, the comblnation with a fixed and a movable card, of greater-Weight scale and a result-scale arranged concentrically with relation to each other, the said'result-scale having a. length e ual to that of the greater- Weight scale p us the length of a lesser- Weight scale, a lesser-Weight scale on the said movable card having Va length proportionate to the length ofthe greater-welght scale and the relative Weight to be given to `the two numbers to be avera ed, slots in the said movable card for eac lesser-Weight `scale through which the divisions of the resultonter to indicate In 'testimony whereof I aHiX my signature in presence of two witnesses.

` WILLIAM H. WATSON. yWitnesses z' BEssIE G. MoRRrs, GEORGE P. DIKEH

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