EP0196869B1

EP0196869B1 - Calendar apparatus and method

Info

Publication number: EP0196869B1
Application number: EP86302232A
Authority: EP
Inventors: Ali Ahmad
Original assignee: Salimul Hassan Alvi
Current assignee: Salimul Hassan Alvi
Priority date: 1985-03-28
Filing date: 1986-03-26
Publication date: 1990-06-27
Anticipated expiration: 2006-03-26
Also published as: JPS61251891A; GB2173021A; EP0196869A1; GB2173021B; GB8508099D0; DE3672314D1; ATE54214T1

Abstract

Calendar apparatus 10 comprises two scale members, namely a fixed main body 12 and a rotatable disc 20. Scales 28 to 42 are printed on the scale members to identify data relating to centuries, years, months, day names and day numbers. The method of the invention permits the calculation of the day names for a chosen month in the past or in the future to be performed by two movements of scale 20.

Description

This invention relates to calendar apparatus providing a method of calculating dates. By the term "calculating dates" as used in this specification it is intended to refer to the identification of the day of the week (Sunday Monday Tuesday etc.) corresponding to a given date in a chosen month and year.
There is disclosed in FR 91348 (addition to FR 1,460,330) (Sergent) calendar apparatus comprising a turnable disc having a peripheral band of day names and internal columns of the year numbers of a century. Associated with this disc is a table containing monthly day numbers and a series of reference numbers. In addition, there is a separate chart whereby one can initially read off the relevant reference numeral forthe relevant month and century of the date in question.
This apparatus, once mastered, may be relatively straightforward to use, but its mode of operation does not lend itselfto a logical sequence of operations. The reference numeral for the date in question is identified by reference to the month and the century concerned-by no means a logical combination. Furthermore, the rotatable disc scale has to contain a large amount of information in the form of numerical data and day names, which renders the apparatus somewhat complex to use.
Accordingly, it is an object of the present invention to provide calendar apparatus providing improvements in relation to one or more of the shortcomings of the prior art, or generally.
According to the invention there is provided calendar apparatus as defined in Claim 1 hereof. An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which:

Figures 1 and 2 show plan views of calendar apparatus in two successive stages of the calculation of a date; and
Figure 3 shows a plan view of a movable scale member of the apparatus of Figures 1 and 2.

As shown in the drawings, calendar apparatus 10 comprises a main body 12 having arcuate cut-outs 14 and 16, and a further arcuate slot 18 for a purpose to be described.
A disc 20 shown in Figure 3 is mounted below main body 12 so as to be visible and actuatable through cut- outs 14, 16 and 18. Disc 20 has apertures 22 for actuation purposes and is mounted for rotation about an axis 24 by means of a pivot pin or the like (not shown) extending through main body 12.
Main body 12 and disc 20 constitute scale members mounted so as to be position-adjustable relative to each other and having printed thereon data defining dates, namely years, months, day names and day numbers. This data is printed in the form of scales whereby the day names can be set with respect to the day numbers for chosen dates within a range of several centuries.
The arrangement of scales on the scale members, 12, 20 is as follows.
Firstly, there are provided year scales 28, comprising a century scale 30, a primary duodecade scale 32, a secondary duodecade scale 34 and a reference scale 36.
Century scale 30 is printed in arcuate form on disc 20 so as to be visible through slot 16 and comprises the numerals 0, 1, 2 and 3 suitably positioned and spaced by means of crosses.
Primary duodecade scale 32 is printed on main body 12 in the form of a generally linear row of numbers, namely 0, 20, 40, 60, and 80. These are suitably spaced by dashes and refer to the duodecades or periods of 20 years within any given century under calculation.
Secondary duodecade scale 34 is printed on main body 12 alongside primary duodecade scale 32. Scale 34 includes the numbers from 0 to 19 within any chosen duodecade. These numbers being suitably positioned for the purpose of the method employed in the apparatus.
Reference scale 36 is printed on disc 20 in arcuate form and alongside scale 30 so as to be visible through arcuate slot 16. Scale 36 comprises reference symbols in the form of letters of the alphabet arranged alongside the century-defining integers of scale 30.
In addition to the year scales 28, there are provided a scale 38 of months, a scale 40 of day names, and a scale 42 of day numbers.
Months scale 38 is printed on main body 12 at the left hand end thereof. The months are arranged in three linear columns and suitably spaced for the purpose of the method. It will be noted that the months of January and February appear twice, once in normal display, and once with accentuation of the boxes in which they appear. These latter occurrences of the months of January and February correspond to leap years for use in the method employed in the apparatus, as described below.
Day name scale 40 is printed in arcuate form on one side of disc 20 so as to be visible through arcuate slot 14 in main body 12, as shown in Figures 1 and 2.
Day number scale 42 is printed on main body 12 at the right hand end thereof to co-operate with the day name scale by means of the printed lines linking the two.
The apparatus is employed as follows. All that is required is to set movable disc 20 to a first or reference position, and then to move it onwards to a final or date position.
Figures 1 and 2 show the use of the apparatus in calculating the name of the day of the week corresponding to a well known date in the past. During the Great War of 1914-1918, Sunday June 25,1916 was the Sunday preceding the start of the combined British and French offensive known as the Battle of the Somme on the following Saturday, July 1st. 1916. The calculation of the name of the day of the week corresponding to 25th. June 1916 (if it were not known) is shown in Figures 1 and 2.
The first step in this process is to set disc 20 to its first or reference position by setting the century scale 30. To set the century scale, one first performs a simple calculation to identify the relevant century on scale 30. To do this, one takes the two digits of the century (19 in this case) and divides them by the number 4, leaving the remainder 3 in this case. The number 3 (corresponding to this remainder) on century scale 30 thus designates the relevant century (for the date 1916) and is then used for setting the first position of disc 20.
This first position of disc 20 is obtained by setting numeral 3 in century scale 30 against the primary duodecade scale 32.
The position on duodecade scale 32 against which numeral 3 should be set is determined by the duodecade concerned. Forthe date calculation process in hand, the relevant numeral in century scale 30 (which is "3" for the twentieth century) is set against the numeral in duodecade scale 32 corresponding to the start of the duodecade concerned. Thus, as can be seen in Figure 2, the numeral 3 in scale 30 has been set against the figure 0 in scale 32, because the duodecade containing the year 1916 (from 1900 to 1920) starts at 0. This isthe first or reference position of disc 20.
To complete the calculation process, disc 20 is moved onwards to its final or date position. This is done by setting a reference symbol corresponding to the year in question on scale 36 of disc 20 (and identified by means of the disc's first position, as described above) against the month in question on month scale 38 on main body 12.
To identify the reference symbol for the year in question on scale 36, the remainder obtained by subtracting the duodecade start number (in this case 1900) from the full number of the year concerned (in this case 1916) is obtained, and in this case is 16. The position of the numeral 16 in the secondary duodecade scale 34 is then used to identify a reference symbol opposite it in reference scale 36. As can be seen from Figure 2, the reference symbol concerned is the letter "E". This symbol corresponds to the year 1916 and now merely needs to be set against the relevant month, namely June, to produce the final or date position of disc 20.
Therefore disc 20 is rotated (by means of apertures 22 using slot 18 and a pointed instrument such as a pencil), until reference symbol E is opposite the relevant month (June in this case). This position is shown in Figure 1. This now defines the final date position of disc 20 and the names of the days of the week corresponding to the relevant days of the month can be seen on scales 40 and 42, and it can be seen that the 25th. June 1916 was indeed a Sunday.
The above process can be employed forcalculat- ing any other required date within the range of the calendar.
Among modifications which could be made in the above embodiment are changes to the exact physical form of the scale members, and the manner in which the scales are printed or represented thereon. It may be possible to provide linearly moving scales corresponding to a slide rule with a suitable cursor. The scale members could be cylindrical or of other forms such as spherical, elliptical etc. Obviously, it is not necessary to have letters in reference scale 36. Any suitable symbol can be employed. Also, if it is not desired to cover multiple centuries as described above, century scale 30 could be modified. For example, it could be marked with the particular limited range of centuries concerned, the relevant one of these then being set against the relevant duodecade etc.
Obviously also, in month scale 38, the actual position of the months could be changed in the lateral direction. The duplicated months January and February as highlighted in this scale are employed in leap years, that is when the year number is divisible by four.
The method of calculation underlying the embodiment described above may be suitable to be programmed into a digital calculator and it is intended that a claim to calculating apparatus so programmed may be included in this application in due course.

Claims

1. Calendar apparatus comprising first and second scale members (12, 20) mounted to be position-adjustable relative to each other, said scale members carrying at least one scale for each of the following data items defining dates namely years (28), months (38), day names (40), day numbers (42), said scales enabling the day names to be set with respect to the day numbers for chosen dates within a range of years, said scales (28,38,40,42) being arranged with respect to said scale members (12, 20) whereby said day names can be set with respect to said day numbers by means of a series of references or symbols (36) on one (20) of said scale members referring to the year of the date in question, and using one of said references or symbols (36) to determine a final or date position of said scale members by reference to the month of the date in question; characterised in that
said scales (28,38,40,42) comprise a seven part month scale (38) on the other (12) of said scale members with the months arranged in seven groups, and a day number scale (42) with the day numbers also arranged in seven groups and also located on the other of said scale members, whereby said identified one of said references or symbols (36) can be set against one of said groups of months by moving said scale members (12, 20) relative to one another thereby to set a scale (40) of said day names, also located on said one (20) of said scale members, against said day numbers (42).

2. Apparatus according to Claim 1, characterised in that said months are arranged on said month scale (38) in groups of one, two and three months, namely two groups of three months, three groups of two months, and two groups of one month, the months of January and February each appearing in two different groups to take account of leap years.

3. Calendar apparatus according to Claim 1 or Claim 2 characterised in that said seven groups of months (38) are arranged opposite said seven groups of day numbers (42) on said other (12) of said scale members, with said groups being aligned with each other.

4. Calendar apparatus according to Claim 3, characterised in that said one (20) of said scale members is arranged as a rotary scale having said identifiable year positions (A to G) or symbols alignable with said groups of months and the names of the days of the week (40) similarly alignable with said day numbers of the month.

5. Calendar apparatus according to Claim 2 characterised in that said two groups of three months comprise February, March and November in one group and January, April and July in the other group, said three groups of two months comprising January and October in one group, Feburary and August in another group, and December and September in the third group, and said two gropus of one month comprising May in one group and June in the other group.

6. Calendar apparatus according to any one of the preceding claims characterised in that said position on said one (20) of said scale members is identified by reference to a year scale on said other of said scale members in the form of a primary duodecade scale (32) identifying periods of twenty years within a century, together with a year scale in the form of a secondary duodecade scale (34) identifying individual years within a twenty year period.

7. Calendar apparatus according to Claim 6 characterised in that said year scale comprises a century scale.

8. Calendar apparatus according to Claim 7 characterised by said century scale serving to identify centuries by means of the remainder when the first two digits of the century are divided by four.

9. Calendar apparatus according to any one of Claims 6 to 8 characterised in that said year scale (32, 34) is located centrally on said other (12) of said scale members between said month scale (38) and said scale (42) of day numbers.

10. Calendar apparatus according to any one of the preceding claims characterised in that said other scale member (12) is a relatively fixed main body of the apparatus, and said one scale member (20) is rotatably mounted thereon.