US2615631A - Computation chart - Google Patents

Description

Get. 28, 1952 A. l. SORRELS 2,615,631

COMPUTATION CHART Filed July a, 1947 Patented Oct. 28, 1952 UNITED STATES PATENT OFFICE COMPUTATION CHART Aaron I. Sorrels, Chicago, Ill.

Application July 3, 1947, Serial No..758,764

3 Claims. l

arrangement of parts hereinafter described and claimed, and will be more readily and easily understood by reference to the'accompanying drawings forming apart of this application, and in which:

Fig. 1 is afront face view of my computation chart embodying the invention, assembled in operative position for use, showing calendar Scale A and menstrual Scale B; and

,Fig. 2 is a cross section taken on diametrical line 2-2 of Fig. 1;

The embodiment of the invention illustrated inthe drawingscomprises a rigid supporting bottom member 3! having a protruding tab 35, a base member injthe form of a disc 2d, preferably constructed of cardboard or other similar material and wherein each part is provided with a centrally located hole 2% adapted to receive a rivet 22 having a burr 23, or other device'for pivotally attaching other elements thereto. The front face of the disc 26 carries a Scale A, reading clockwise, comprising circumferentially positioned and radially arranged graduation marks 24 forming spaces 25, divided into four tables,

CO-Willi table fa showing February, 28 spaces for estimating 28 days; table 1, March, August and December, 31 spaces for estimating .31 days; table 8, April, June, September and November,

30 spaces for estimating 30 days; and table 8 showing January, May, July and. October, 31 :spacesfor estimating 31 days.

The above combinations of months discloses the purpose of placwhich the menstrual period begins and continuing over into the next table, it is possible to arrive at a correct date calculation without difliculty, as will be readily understood.

It is common authoritative knowledge that normal menstrual periods vary from approximately twenty-four to thirty days in individuals. Because of this variation in length a Scale B is provided which refers particularly to menstrual periods of varied lengths. The Scale B is carried on the outer face of an arcuate indicator 25 rotatably arranged over the said disc 28, being pivotally mounted thereon and thereto on the rivet 22, and extends in radial alignment with the graduation marks 24 of Scale A carried by the disc 28. The indicator 25 carries a plurality of concentric rows 23 of graduated spaces 25. The first or upper row numbers 2 to 31 inclusive, corresponding to the greatest number of days in a month. In the last radial column 29 are figures representing olifierent lengths of normal menstrual periods beginning with 24 and ending with 30, showing the total number of the days in that period. It is further to be noted that the numbering of spaces 25 in the circumferential rows 28 indicated by the totals 24 to 30 are numbered'in reverse from 20 to 1, followed by the capital letter M. The letter M on Scale B indicates the beginning day of the next menstruation period. By this arrangement it can be determined the exactnurnber of days from a given 'date to the beginning or" the next menstrual period. The encircled 15 on Scale B indicates the approximate date in theory that conception takes place,-or at about the 15th day before the next menstrual flow. The numbers at the outer circumierence of Scale B also indicate the number of days from the start of the last period to the beginning of the next period. An arrow 21 serves to locate the point of setting of the said Scale B relative to the Scale A. For persons following the herein-described method of determining date of the time of conception, which is believed to take place on or about the fifteenth day before the due date of the next menstrual period. Reference being further had to lines 23 and the arrow 21.

It is generally accepted belief that the conception date occurs on the fifteenth day before the next normal menstrual occurrence. To facilitate the ready location of this date, each or" the con centric lines carry the letter M at its righthand termination, and an index figure as to the number of days in its respective concentric line of the table B bearing reference numeral 28 It Will be noted that in each concentric column the intervening spaces between 28 and II are bordered by heavy marginal lines 34 and separated by a round open space, each containing the figure 15. Each of these 25 spaces is believed to be the day when conception takes place. This marking and margining the spaces 34 is to guide the operator in the concentric column of a selected length of the selected term of menstrual period.

In use, the Scale A affords a simple arrangement of months having 28, 30 or 31 days into four tables, 6, I, 8 and 9, shown in Fig. 1, by which menstrual periods involving a 31-day month followed by a 28-day month, as table 9 followed by table 6; a 28-day month followed by a 31-day month, as table 6 and table 1; a 31-day month followed by a 30-day month, as tables 1 and 8; and a 30-day month followed by a 31-day month, as tables 8 and 9. By this arrangement one hundred and twenty spaces 25 suffice to show the twomonth period combinations in a year of 365 days. The Scale B carried by the arcuate indicator 26 shows detail matters concerning the menstrual period which is applicable whether the period is wholly within one month or involves days within two consecutive months. Each important day in the period can easily be determined by proper arrangement of the Scale B over the Scale A. Another practical use of Scale B is to determine the approximate date of conception and is obtained from the use of Scale B properly set over Scale A and with the number of days in te menstrual period known, and then counting back 15 days from the due date of the first menstrual omission, the approximate date of conception can be learned. From this date the period of gestation will last about 280 days.

Instructions for the use of the chart (For an example, the subjects last period began February 15th. Her normal period is 28 days, making her next period due on March 15th. Her periods vary from 26 to 30 days.)

1. To use the chart to calculate a normal period:

Step 1.Set arrow on left side of Scale B at the date last period began. In the subjects case it is February 15th, which appears on Scale A.

Step 2.--The subjects next period occurs March 15th. Keep the arrow on February 15th, follow along on Scale A to the 15th. Reading below and one square to the left on the top of Scale B, We find it was a 28-day period.

St p 3.Follow the above instructions on determining each period for eight to ten months.

Total 280 days days days days days days days days days days days divided by 10, which is the number of periods, equals 28 days, which is the subjects normal period.

2. To use the chart to determine when the next period will occur:

the date last period began. In the subject's case it is February 15th, which appears on Scale A.

Step 2.'Ihe subjects normal period is 28 days. Keep the arrow on February 15th. Follow along the top of Scale B for 28 days. Read above and one square to the right on Scale AMarch 15th for the date next period begins.

Or: Keep arrow on February 15th. Select the normal period column on Scale 13. In the subjects case it is 28. Follow to the left to the letter M. Read above on Scale A-March l5ththe date next period begins.

3. To use the chart to determine the date of conception and expected date of birth:

Step 1.Set arrow on left side of Scale B at the date last period began. In the subjects case it is February 15th, which appears on Scale A.

Step 2.Keep the arrow on February 15th. Select the column on the right side of Scale B, which corresponds to the subjects normal period,

' 28. Move to the left in the 28 column'to the encircled 15. Read directly above on Scale A- February 28ththe approximate date of conception.

4. To determine non-fertile days of the subject:

Step 1.Set arrow on left side of Scale B at the date last period began. In the subjects case it is February 15th, which appears on Scale A.

Step 2.-To allow for the subjects occasional variation from a 26 to a 30-day period, check column 28 and 30 on the right side of Scale B.

Keep the arrow on February 15th. Select column 26 on right side of Scale B. Follow to the left to the darkly outlined number 19 and read above on Scale A-February 22ndsubjects first fertile day. Then, on column 30, move to the left to the darkly outlined number 12 and read above on Scale AMarch 5th--subjects last fertile day. Therefore, February 22nd to March 5th inclusive are the subjects fertile days.

5. Adjustments to be made on the chart for use during leap year:

1. For leap year, when the period occurs in February and extends into March, one day should be subtracted from the date next normal period begins to allow for the 29th day of February.

2. For leap year when the period of pregnancy continues through February, subtract one day from the expected date of birth to allow for the 29th day of February.

While I have illustrated and described a precise arrangement for carrying the invention into a practical, effective use, this is capable of many variations, modifications and alterations without departing from the spirit of the invention. I therefore do not wish to be limited by the description and drawings forming a part of this specification, but desire to avail myself of such changes as may fall within the spirit and scope of the appended claims.

I claim:

1. In combination, a computation chart comprising a flat circular base having a plurality of graduations, in continual alignment adjacent the marginal edge thereof; a plurality of calendar date reading from left to right and comprising a plurality of months arranged in a plurality of groups having a similar ending as to the number of days therein, and another group of months directly following having a group of months each having a similar number of days but at variance with the said first named group; an arcuate indicator rotatably mounted at the center of said circular base; graduations at the marginal edge of said rotatable Step 1.--Set arrow on left side of Scale B at indicator arranged t b passed t radial alignment with the graduations carried by said circular base and reading from left to right and corresponding with calendar monthly dates from 28 days to 31 days; a menstruational table comprising a plurality of concentric rows comprising seven (7) rows, each of a normal duration numbering from (24) twenty-four days to (30) thirty days arranged to read from right to left from the normal due date the particular length of the period selected; each of the foregoing periods having its twelfth to nineteenth margined in heavy separation lines; and the fifteenth day previous to the normal menstrual period arranged within a circular margin indicating the date of conception.

2. A computation chart of the class described comprising a circular dial having a plurality of graduations reading from left to right adjacent its peripheral edge indicating days; the said graduations being arranged substantially in four contiguous major groups sequentially as to the calendar dates of the last day of a month with the first day of the next following month; an arcuate indicator rotatably mounted at the center of said dial; indicia on said arcuate indicator for manually selective radial alignment with indicia carried by the peripheral edge of said dial; a table of normal menstrual periods of different lengths sequentially arranged in concentric alignment adjacent the outer edge of said arcuate indicator; and an interval of eight days, from the 12th through the 19th day before the normal due date of the next menstrual due date, said interval in each of the periods bordered by heavy lines indicating the general period of conception.

3. The construction specified in claim 2 in which the day of conception is indicated by a circular space bounded by a square lined enclosure and containing the numeral 15.

AARON I. SORRELS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 784,660 Chritton Mar. 14, 1905 1,435,512 Boggio Nov. 14, 1922 2,076,242 Marquis Apr. 6, 1937 2,098,622 Gronwold Nov. 9, 1937

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