GB2178560A

GB2178560A - Perpetual calendars

Info

Publication number: GB2178560A
Application number: GB08517259A
Authority: GB
Inventors: Tan Hua Yong
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-07-08
Filing date: 1985-07-08
Publication date: 1987-02-11
Also published as: GB8517259D0

Abstract

Three relatively moveable members 10, 12 and 14 are marked with sets of markings 18, 20, 22 and 24 indicating days of the week, years of a century, hundreds of years and months of the year respectively and with a pointer 28 such that the relative movement enables the markings to be brought into registration so as to indicate the day of the week corresponding to a specific date. The members may be three concentric discs of different radius with the markings arranged in annular formations divided into seven segments by radial lines. Alternatively the members may be two cylindrical drums 62 and 63 which are rotatable mounted within a third scale member comprising a casing 61 such that selected portions of their respective cylindrical surfaces can be displayed at windows 64 and 65 in the casing. <IMAGE>

Description

SPECIFICATION Perpetual calendars This invention relates to calendars.

According to the present invention, there is provided a device for calculating the days of the week on which dates fell/will fall comprising first, second and third relatively moveable scale members, the members being marked with four sets of markings representing hundreds of years, the years in a century, the months in a year and the days in a month, so that a date can be defined by reference to a marking selected from each set, the members also being marked with a set of markings representing the days in a week, and the members also being marked either with a pointer or with a further set of relevant markings, one of the sets of markings or the pointer being provided on the first member in an associated pair with another of the sets of markings or the pointer provided on the second member, another of the sets of markings or the pointer being provided on the second member in an associated pair with another of the sets of markings or the pointer provided on the third member, another of the sets of markings or the pointer being provided on the third member in an associated pair with the remaining sets of markings or the pointer which is provided on the first member, selected markings from associated pairs being registrable upon relative movement of the members on which those markings are provided so that selected markings from said four sets can be registered to define a selected date, and the markings being such that, upon such registration to define a selected date, registration is made with that one of the markings in the days of the week set which represents the day of the week on which that selected date fell/will fall.

Under the current Gregorian calendar system and the earlier Julian system, February has 28 days except on a leap year when it has 29 days. Under the Julian system, every year divisible exactly by four was a leap year. However under the Gregorian system, centesimal years (e.g. 1900, 2000, 2100) are not leap years unless they are divisible exactly by four hundred (e.g. 2000).

The device may be arranged such that the years in a century set of markings include duplications in adjacent divisions of the markings representing every fourth year (0, 4, 8 and so on) and an indication as to which of the duplicated markings to use when calculating the day of the week for dates in other months.

Alternatively, it may be arranged such that said further set of relevant markings is provided, one of said further set providing an indication for registration when calculating the day of the week for a date in January or February in a leap year and another of said further set providing an indication for registration when calculating the day of the week for dates in other months.

During the 16th century, Pope Gregory XIII decreed that the day after Thursday 4th October 1582 shall be Friday, 15th October 1582, thus dropping 10 days. The Gregorian system was then used in Italy, but was not adopted in England until 1752, when 11 days was dropped.

The device may be used for calculating days of the week on which dates fell/will fall under the Julian system up to a particular time and under the Gregorian system after that particular time, and may be arranged such that the hundreds of years set of markings include a duplication of the marking representing the hundred years during which that particular time fell and an indication as to which of the duplicated markings to use for dates before and after that particular time. Alternatively, the device may be arranged such that said further set of relevant markings is provided, one of said further set providing an indication for registration when calculating the day of the week for dates before that particular time and another of said further set providing an indication for registration when calculating the day of the week for dates after that particular time.

There follows a description by way of example of specific embodiments of the present invention, reference being made to accompanying drawings, in which: Figures 1, 2 and 3 are views of three scale members of a first device according to the present invention having three card discs rotatable about a central pin; Figure 4 is a rear view of the scale member of Figure 3; Figures 5 to 8 show the device of Figures 1 to 4 in positions for calculating the day of the week on 29th February 1984, 1st March 1984, 9th October 1582 and 15th October 1582, respectively; Figure 9 is a perspective view of a second device according to the present invention and having cylindrical drums rotatable within a casing; Figure 10 is a perspective view of a drum used in the device of Figure 9; Figure 11 is a side elevation of the device of Figure 9;; Figure 12 is a planar projection of the markings applied to the cylindrical surface area of the upper drum of Figure 9, and Figure 13 is a similar projection corresponding to the lower drum of Figure 9.

Referring to Figures 1 to 3, the three scale members 10, 12, 14 are card discs which are secured together and rotatable about a central fastening pin.

Referring to Figure 1, the smaller scale member 10 is marked with seven equally spaced radiating lines 16 which divide an outer set of markings 18 into seven divisions and an inner set of markings 20 also into seven divisions. The divisions of the outer set 18 are marked sequentially clockwise with the days of the week. The divisions of the inner set 20 are marked with the years of a century. Working clockwise around the inner set and starting with the division in the same segment as "Friday", the years increment from "00" by one per division with every fourth year (00, 04, 08 etc) being duplicated, the first of each duplicated pair being enclosed in a square and the second in a circle.

Referring to Figure 2, the intermediate scale member is likewise marked out as seven segments with an inner set 22 of markings and an outer set 24. The divisions of the inner set 22 are marked with hundreds of years and the divisions of the outer set 24 are marked with the months of the year.

In the months of the year set 24, the clockwise increment around the scale member from one month to another is equal to the number of days in said one month less 28.

Thus, February is 3 divisions clockwise from January because the number of days in January is 3 greater than 28. For this purpose, February is treated as having 28 days, and thus February and March occupy the same division.

In the hundreds of years set 22, "00" is in the same segment as "August". Running clockwise around the scale, the hundereds of years increment from "00" by 1 every division until "15". This "15" is identified with a triangle and is in the same segment as "February", "March" and "November". A further "15" is marked in the same segment as "April" and "July" and is identified by a diamond. Running clockwise from the "15" in a diamond, the hundreds of years increment from one number to another number either every division in the case where said other number is divisible exactly by 4, or every other division in the case where said other number is not so divisible.

Referring to Figure 3, the outer scale member 14 is also divided into seven segments, and an outer set 26 of markings are marked with the days of the month (1 to 31). Starting from 1, and running clockwise, the day of the month increments by 1 every division.

The outer scale member also is marked with a "Month" pointer 28 in the same segment as the days of the month "7", "14", "21" and "28".

Referring to Figure 4, the rear of the outer scale member may be marked with instructions for use of the square, triangle and diamond symbols.

Referring to Figure 5, there follows a description as to how to use the device to calculate the day of the week on which 29th February 1984 fell.

Firstly, the inner and intermediate members 10, 12 are rotated so that the division 30 containing "19" registers with the division 32 containing "84" in the square, representing the year 1984. (Referring to Figure 4, the square is used rather than the circle because the month is February in a leap year.) Secondly, the outer member 14 is moved relative to the other two members 10, 12 so that the "Month" pointer registers with the division 34 containing "February". Then, the day of the week is read from the division 36 in the day of the week set 18 which is registered with the division 38 containing "29" and representing the 29th day of the month. It can be seen from Figure 5 that 29th February 1984 fell on a Wednesday.

Referring to Figure 6, the device is shown in position for calculating the day of the week of the next day, 1st March 1984. The division 30 representing the 1900's is this time registered with the year division 40 containing "84" in a circle. The intermediate and outer member are in the same relative position as for Figure 5. Figure 6 confirms that 1st March 1984 fell on a Thursday, since the division 42 containing "1" registers with the division 44 containing "Thursday".

The device shown in the drawings is arranged so that it gives the day in the week under the Julian system for dates up to and including 4th October 1582 and under the Gregorian system for dates on or after 15th October 1582.

Referring to Figure 7, the device is positioned to show the day of the week on 4th October 1582. The division 46 containing "15" in a triangle is registered with the division 48 containing "82" The "Month" pointer 28 is registered with the division 50 containing "October". Registration of the division 52 containing "4" with the division 54 indicates that 4th October 1582 fell on a Thursday.

Referring to Figure 8, the device is positioned to show the day of the week on the next day, 15th October 1582. In this case, the division 56 containing "15" in a diamond is registered with the division 48 containing "82". Registration of the division 56 containing "15" confirms that 15th October 1582 fell on a Friday.

The specific device described above may be modified in a number of ways.

The duplicated markings may be distinguished in other ways, for example by use of colours or different type styles.

Rather than duplicating leap years and the 1500's markings, the "Month" pointer 28 on the outer member 14 may be replaced by a set of markings in various divisions which may be marked to indicate whether they are to be registered in January or February in a leap year, or not, or are to be registered in the 1500's up to 4th October 1582 or from 15th October 1582.

The device may be modified to take account of the transition from the Julian system to the Gregorian system at a time other than at the end of 4th October 1582, for example in 1752.

An alternative form of marking (not shown) replaces the hundreds of years set of markings and the years of a century set of markings by a merged set of year numbers marked on the smaller scale member 10 and a year pointer on the intermediate scale member 12 so that the smaller and intermediate scale membmers are registered by aligning the pointer with the required year number.

An alternative embodiment of the invention is shown in Figure 9 which shows a second device 60 in which the first and second scale members are upper and lower cylindrical drums 62 and 63 respectively which are rotatably mounted within a third scale member comprising a casing 61 such that selected portions of their respective cylindrical surfaces can be displayed at windows 64 and 65 in the casing. The drums as shown in Figure 10 have axles 66 which are journaled in slots -67 in the casing and which project from the casing to also serve as handles by which the drums may be rotated.

The slots 67 communicate with a rear portion of the casing such that drums may be readily inserted or removed and a rear cover plate 68 of the casing serves to retain the drums in use.

As shown in Figure 11, a support is hinged to the casing to enable the casing to be supported in a vertical position or to be laid horizontally with the support folded against the rear of the casing's lower portion 70.

The device 60 has a planar display 71 on the front surface of the casing's lower portion 70 bearing markings (not shown) in seven divisions or columns. One set of markings represents the seven days of the week and the other set the years in a century, these markings corresponding to those appearing on the smaller scale member 10 of the embodiment of Figures 1 to 8.

Figure 10 shows the upper drum 62 which is marked with circumferential lines 72 dividing the cylindrical area into seven annular areas 73 which are subdivided by axial lines 74 to provide a total of 49 segments. The window 65 is dimensioned such that by rotation of the drum any one of seven possible groups of axially aligned segments can be selected for display, each group including seven divisions which lie directly above the seven corresponding divisions of the planar display 71.

The markings applied to the 49 segments are shown in Figure 12 in which horizontaily aligned segments correspond to axially aligned segments on the drum. Considering the uppermost row of segments, successive segments from left to right are marked with successive days of the month 1 to 7, 8 to 14, 15 to 21, 22 to 28 and 29 to 31. A "MONTH" pointer is also provided in the right hand segment.

Succeeding rows of segments carry the same markings but with a cyclical shift to the right between successive rows so that for example rotation of the drum to upwardly move the displayed surface to display an adjacent row of segments at the window results in a shift to the right of the markings displayed to adjacent columns, the rightmost segment markings being recycled to the leftmost segment.

The lower drum 63 is similarly divided into 49 segments and carries the markings shown in Figure 13. As with the upper drum 62, rotation results in a sideways shift in the displayed markings. The lower drum 63 is marked with an upper set 75 of markings denoting months of the year and a lower set 76 denoting hundreds of years in seven divisions.

The planar display 71 carries seven columns of markings denoting years of a century in seven divisions and also the 7 days of the week.

The operation of the device is analogous to that of the card disc device except that movement of the displayed markings is accommodated by rotation of the drums instead of by rotation of the card discs. The device can be used for both Julian and Gregorian dates but if only Gregorian dates are required then the numbers 00 to 15 may be omitted from the lower drum markings.

Rather than being applied to discs or to drums the markings may be applied to other relatively moveable members, for example linearly sliding members.

The device may also be adapted to provide other functions, for example a map of the world and a relatively moveable time marked scale may be provided so that time difference around the world can be calculated.

Claims

1. A device for calculating the days of the week on which dates fell/will fall comprising first, second and third relatively moveable scale members, the members being marked with four sets of markings representing hundreds of years, the years in a century, the months in a year and the days in a month, so that a date can be defined by reference to a marking selected from each set, the members also being marked with a set of markings representing the days in a week, and the members also being marked either with a pointer or with a further set of relevant markings, one of the sets of markings or the pointer being provided on the first member in an associated pair with another of the sets of markings or the pointer provided on the second member, another of the sets of markings or the pointer being provided on the second member in an associated pair with another of the sets of markings or the pointer provided on the third member, another of the sets of markings or the pointer being provided on the third member in an associated pair with the remaining set of markings or the pointer which is provided on the first member, selected markings from associated pairs being registrable upon relative movement of the members on which those markings are provided so that selected markings from said four sets can be registered to define a selected date, and the markings being such that, upon such registration to define a selected date, registration is made with that one of the markings in the days of the week set which represents the day of the week on which that selected date fell/will fall.

2. A device as claimed in Claim 1 wherein the scale members are relatively rotatable about a common axis.

3. A device as claimed in Claim 2, wherein said four sets of markings and the days of the week set of markings each have seven, or a multiple of seven, divisions each of equal angular length arranged around the axis.

4. A device as claimed in Claim 1, wherein the scale members are linearly moveable parallel to each other.

5. A device as claimed in Claim 4, wherein over a repeat length of the scale members, said four sets of markings and the days of the week set of markings each have seven divisions each of equal linear length.

6. A device as claimed in Claim 1 wherein the first and second scale members are drums rotatably mounted about parallel axes and with respect to the third member and wherein the drum surfaces and a display area of the third member carry markings with seven axially spaced division in co-operating alignment.

7. A device as claimed in Claim 6 wherein the third scale member is a casing within which the drums are mounted and including windows displaying seven axially aligned marked segments of each drum.

8. A device as claimed in Claim 7 wherein drum markings are repeated around the circumference of each drum with an axial displacement between successive repeated markings such that rotation of the drum to display a circumferentially adjacent marked segment results in an axial shift from one division to another of the displayed marking.

9. A device as claimed in any of Claims 2 to 8, wherein each division of the days of the week set of markings is marked to represent a respective day of the week, and those divisions are ordered to represent consecutive days of the week.

10. A device as claimed in any preceding claim, wherein the years in a century set of markings include duplications in adjacent divisions of the markings representing every fourth year (0, 4, 8 and so on) and an indication as to which of the duplicated markings to use when calculating the day of the week for a date in January or February in a leap year, and when calculating the day of the week for dates in other months.

11. A device as claimed in any of Claims 1 to 10, wherein said further set of relevant markings is provided, one of said further set providing an indication for registration when calculating the day of the week for a date in January or February in a leap year and another of said further set providing an indication for registration when calculating the day of the week for dates in other months.

12. A device as claimed in any preceding claim for calculating days of the week on which dates fell/will fall under the Julian system up to a particular time and under the Gregorian system after that particular time, wherein the hundreds of years set of markings include a duplication of the marking representing the hundred years during which that particular time fell and an indication as to which of the duplicated markings to use for dates before and after that particular time.

13. A device as claimed in any of Claims 1 to 11 for calculating days of the week on which dates fell/will fall under the Julian system up to a particular time and under the Gregorian system after that particular time, wherein said further set of relevant markings is provided, one of said further set providing an indication for registration when calculating the day of the week for dates before that particular time and another of said further set providing an indication for registration when calculating the day of the week for dates after that particular time.

14. A device as claimed in any preceding claim, wherein the hundreds of years set and the years of the century set are one of the associated pairs, and wherein the days of the month set and the days of the week set are another of the associated pairs.

15. A device as claimed in any preceding claim wherein the hundreds of years set of markings and the years of a century set of markings are merged to form a set of year numbers marked on one of the members and an additional pointer is provided on another member.

16. A device for calculating the days of the week on which dates fell/will fall, substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 8 the accompanying drawings.

17. A device for calculating the days of the week on which dates fell/will fall, substantially as hereinbefore described with reference to and as illustrated in Figures 9 to 13 of the accompanying drawings.