Globe having means for indicating a day and night boundary

A globe, comprising: a stationary base; a day and night boundary ring mounted on the stationary base; an arm supported at its base end by the day and night boundary ring so as to be rotatable around a first axial line; and a spherical globe main body rotatably supported by a free end of the arm so as to be rotatable around its earth's axis; the first axial line defining the ecliptic angle with respect to a vertical line. According to this globe, the distribution of the regions of day and night in any time of the day and in any time of the year can be readily demonstrated by means of the day and night boundary ring simply by turning the globe body around the earth's axis and the first axial line, respectively, without using any complicated structure.

TECHNICAL FIELD 
The present invention relates to a globe having means for indicating a day 
and night boundary, in particular to such a globe which can demonstrate 
how day and night regions on the earth change according to the time of the 
day and the month/season of the year. 
BACKGROUND OF THE INVENTION 
A conventional globe is suitable for demonstrating the oceans and 
continents on the earth in three-dimensions, but is not suitable for 
demonstrating the times of sunrise and sunset in various places on the 
earth in different times of the year. 
Japanese patent laid open publication No. 60-100169 discloses an 
illumination device and a semi-spherical light shield both disposed in a 
semi-transparent hollow globe to demonstrate the regions of day and night 
on the earth. The light shield is rotatably supported around a vertical 
axial line and can be angularly adjusted with a knob which is detachably 
mounted on top of the globe. 
This globe however requires a supply of electricity, and a complex 
structure must be incorporated in the interior of the globe. Therefore, 
its assembly process is highly complex, and the manufacturing cost is 
inevitably high. 
BRIEF SUMMARY OF THE INVENTION 
In view of such problems of the prior art, a primary object of the present 
invention is to provide a globe which is simple in structure and can 
demonstrate the regions of day and night on the earth not only in 
different times of the day but also in different times of the year. 
A second object of the present invention is to provide a globe which can 
demonstrate the meridian altitude angle of the sun at any time of the 
year. 
These and other objects of the present invention can be accomplished by 
providing: a globe, comprising: a stationary base; a day and night 
boundary ring mounted on the stationary base; an arm supported at its base 
end by the day and night boundary ring so as to be rotatable around a 
first axial line; and a spherical globe main body rotatably supported by a 
free end of the arm so as to be rotatable around its earth's axis; the 
first axial line defining an ecliptic angle with respect to a vertical 
line. 
In this way, the distribution of the regions of day and night in any time 
of the day and in any time of the year can be readily demonstrated by 
means of the day and night boundary ring simply by turning the globe main 
body around the earth's axis and the first axial line, respectively. 
According to a preferred embodiment of the present invention, a horizontal 
ring is fixedly supported by the base so as to coaxially surround the 
globe main body in a plane perpendicular to the day and night boundary 
ring and passing through the center of the globe main body. Alternatively, 
the day and night boundary ring may be rotatable within a plane of its 
major surface with respect the horizontal ring. To simply and clearly 
indicate the month and/or the season of the year in relation with the 
distribution of the regions of day and night, a month/season indicator may 
be provided on the arm between the base and free end. 
If desired, the month/season indicator may be integral with the arm. 
To show the meridian altitude of the sun at any time of the year, a 
meridian altitude indicator consisting of a band member may extend along a 
surface of the globe main body, and be pivoted at its one end to the base 
so as to be rotatable around an axial line perpendicular to the night and 
day boundary ring and passing through the center of the globe main body 
and provided, at its other end, with a longitudinal slot engaging with a 
pin which is coaxial with said earth's axis of said globe main body. 
If the day and night boundary ring is mounted on the base by way of an 
intermediate member which is rotatable relative to the stationary base by 
an axial line defining half the ecliptic angle relative to a vertical 
line, the globe main body may be supported in either one of the two 
orientations, one with its earth's axis directed vertically, and the other 
with its earth's axis defining an ecliptic angle relative to the vertical 
line.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIGS. 1 through 3 show a first embodiment of the globe according to the 
present invention. This globe 1 comprises a globe main body 2, and a base 
5 supporting the globe main body 2 by way of a pair of arms 3 consisting 
of moveable supports for the globe main body 2 and a night and day 
boundary ring 4. The globe main body 2 is supported by free ends of the 
arms 3 at their opposite poles by way of a pair of pivot portions 6 so as 
to be rotatable around its earth's axis P. The based ends of the arms 3 
are supported by pivot portions 7 provided at upper and lower ends of the 
night and day boundary ring 4 so as to be rotatably around an axial line Q 
which intersects with the earth's axis P at the center of the globe main 
body 2 defining a certain angle A, for instance 23.44 degrees or the 
ecliptic angle, relative to the earth's axis P. The upper end of the base 
5 is formed as a horizontal ring 8 which is engaged with the night and day 
boundary ring 4 at their middle parts in a mutually perpendicular 
relationship. The lower end of the night and day boundary ring 4 is 
engaged with a slot provided in a central part of the base 5. The night 
and day boundary ring 4 can slidingly rotate relative to the base 5 as 
well as the horizontal ring 8, in a plane containing its major surface. 
Alternatively, the day and night boundary ring 4 may be integrally attached 
to the horizontal ring 8 and the base 5. 
The upper surface of the horizontal ring 8 on one side of the night and day 
boundary ring 4 is provided with a central indicator 9 for indicating that 
the position of the sun, and arrows 10 one either side of the indicator 9 
to show the direction and magnitude of the solar radiation. The upper end 
of the night and day boundary ring 4 is centrally provided, on one side 
thereof, with an indicator 11 indicating the part of the earth on this 
side of the night and day boundary ring 4 is daytime, and the parts on the 
same side of the night and day boundary ring 4 adjacent the horizontal 
ring 8 are provided with marks 12 and 13 indicating that the sun is rising 
and setting in the associated regions of the earth, respectively. 
Referring to FIG. 3, a month/season indicator disk 14 is fixedly secured to 
the night and day boundary ring 4 so as to surround the upper pivot 
portion 7. The month/season indicator disk 14 carries numerals 1 through 
12 and/or four seasons along its outer circumference at equal interval to 
indicate the twelve months and/or the four seasons of the year. The upper 
end of the upper arm 3 is provided with an arrow 15 to point at one of the 
twelve numbers or the four seasons. 
Referring to FIG. 1, an arcuate meridian elevation indicator band 16 
extending along the surface of the globe main body 2 is pivotally 
supported at its middle part by a part of the horizontal ring 8 adjacent 
the sun indicator 9 by way of a pivot shaft 17 extending perpendicularly 
to the major surface of the night and day boundary ring 4. The upper and 
lower end portions of this meridian elevation indicator band 16 are each 
provided with a slot 16a receiving the pivot shaft of the pivot portion 6 
in such a manner that the meridian elevation indicator band 16 can rotate 
over a certain angle around the pivot portion 17 following the rotational 
movement of the arms 3, with its slots 16a guided by the pivoted portions 
6. In other words, the meridian elevation indicator band 16 is always 
located on the equinox of the globe main body 2 as it pivotally moves 
around the pivot shaft 17 along the surface of the globe main body 2. 
Now the operation of this embodiment is described in the following. First 
of all, the solid lines in FIG. 2 show the relationship between the earth 
and the sun at summer solstice. The side of the day and night boundary 
ring 4 closer to the sun indicator 9 or to the left in FIG. 2 represents 
daytime, and the other side of the day and night boundary ring 4 
represents night. The arrow 15 on the arm 3 points substantially at number 
6. When the globe main body 2 is turned around its earth's axis P, it can 
be seen that the region near the upper pivot portion 6 or the north pole 
always stays in the daytime zone. 
When the arm 3 is turned around the axial line Q as shown by the imaginary 
lines in FIG. 2 until the arrow 15 points at number 12 on the month/season 
indicator disk 14, the relationship between the earth and the sun at 
winter solstice is produced. Then, it can be seen that the region near the 
north pole is now located to the right in FIG. 2 and always stays in the 
night zone. 
In this way, according to the globe of the present invention, the state of 
day and night in any geographical point on the earth as well as its 
seasonal changes can be instinctively and simply understood. 
The elevation of the sun when it crosses the meridian can be known by 
turning the globe main body 2 around its earth's axis P to bring the 
particular region upon the meridian elevation indicator band 16 and 
reading the angle marked on the meridian elevation indicator band 16. If 
desired, at least one of the day and night boundary ring 4, the horizontal 
ring 8 and the meridian elevation indicator band 16 may be made from a 
transparent material to avoid obstructing the view of the globe main body 
2. 
FIGS. 4 and 5 show a second embodiment of the present invention, and like 
parts are denoted with like numerals. According to this embodiment, the 
month/season indicator disk is integral with one of a pair of moveable 
support arms 23 pivotally supporting the globe main body 2, and the base 
ends of the moveable support arms 23 are pivotally supported by upper and 
lower ends of a C-shaped stay 28 which is in turn fixedly supported by a 
fixed base 25. A day and night boundary ring 4 is also fixedly attached to 
the upper and lower ends of the C-shaped stay 28. The upper end of the 
stay 28 is further provided with a pointer 29 for pointing at one of the 
numerals indicating the months and/or the seasons of the year. Otherwise, 
the present embodiment is similar to the previous embodiment. 
FIG. 6 shows a third embodiment of the present invention. According to this 
embodiment, a day and night boundary ring 34 is pivotally supported by the 
free ends of a U-shaped stay 38 which is centrally and fixedly supported 
by a base 35. The globe main body 2 is supported only by the day and night 
boundary ring 34 by way of a pair of moveable support arms 33. This 
embodiment is otherwise similar to the second embodiment. 
FIG. 7 shows a fourth embodiment of the present invention. According to the 
present invention, the day and night boundary ring 44 consists of a 
transparent planar member provided with a circular opening for receiving a 
globe main body 2 therein, and is directly and securely attached to a base 
45. This embodiment is otherwise similar to the third embodiment. 
FIGS. 8 and 9 show a fifth embodiment of the present invention. According 
to this embodiment, a rotatable support member 58 is supported by a base 
55 by means of a pivot shaft 59 which is inclined by 11.72 degrees or half 
the ecliptic angle with respect to a vertical line. A month/season 
indicator ring 58a is integrally secured to the support member 58, and a 
base end of support arm 53 is pivotally supported by the support member 58 
coaxially and around a vertical line Q, as seen in FIG. 8, which lies in 
the same plane as a day and night boundary ring 54 (which is described 
hereinafter). The globe main body 2 is rotatably supported at its south 
pole by a free end of the support arm 53 around the earth's axis P. The 
rotatably support member 58 further integrally supports the day and night 
boundary ring 54. 
Thus, the globe main body 2 is supported in such a manner that the plane of 
the major surface of the day and night boundary ring 54 is perpendicular 
to a horizontal plane in the normal way of supporting a globe as shown in 
FIG. 8, but, by turning the rotatable support member 58 by 180 degrees 
around the pivot shaft 59 with respect to the base 55, the globe main body 
2 may be supported in such a manner that the earth's axis P coincides with 
a vertical line as shown in FIG. 9. According to this embodiment, the 
globe main body 2 is supported only at its south pole end, and the 
appearance of the globe may be improved. 
According to the embodiments illustrated in FIGS. 10 and 11, the seasons 
and/or the months of the year are marked on support bases 65 and 75 and 
moveable support arms 63 and 73 are provided with pointers 69 and 79, 
respectively, for indicating the season or the month associated with each 
different state of the globe main body 2. These embodiments are otherwise 
provided with similar structures to that of the fifth embodiment. 
Although the present invention has been shown and described with respect to 
detailed embodiments, it should be understood by those skilled in the art 
that various changes and omission in form and detail may be made therein 
without departing from the spirit or scope of this invention.