TECHNICAL FIELD

The invention relates to chronological instruments. More specifically, the invention relates to methods and apparatus indicating day/night demarcations on planetary models.

BACKGROUND OF THE INVENTION A variety of methods and techniques have been developed for simulating the appearance of sunlight on world globe models. In most embodiments of this concept, a globe model representing the earth is internally illuminated by a baffled light source. The globe is typically semi-transparent, and the baffle is arranged so that one half of the globe is in simulated sunlight, while the remaining half is in simulated darkness. Manual or automatic mechanisms are employed to rotate the globe and baffle with respect to one another so that the demarkation between the night and day hemispheres of the globe rotate once each day (typically one revolution every 23 hours, 56 minutes to simulate sidereal time) .

The prior art mechanisms for simulating this day/night demarkation range from simple to complex, from manual to automatic. One of the earliest prior art devices is described by Schulse in U.S. Patent No. 1,959,601 issued on May 22, 1934. Schulse describes a globe which rotates once each 24 hours. A lamp is fixed within and with respect to the globe behind a shield/filter to produce the desired day/night effect.

The filter itself rotates about the lamp on an axis which is displaced 23.5 degrees with respect to the polar axis of the globe once each 365 days to simulate the effect of the seasons on the day/night illumination pattern. A conventional clock automatically drives the globe and shield/filter. Schulse's mechanism is relatively complex involving multiple gear trains and slip clutches, worm drives and concentric, rotating shafts all of which contribute to a relatively expensive chronological instrument. Devices such as this have not been readily accepted into the marketplace.

Others, such as Carlson in U.S. Patent No. 4,936,779 have provided an internally illuminating globe which simulates the day/night pattern on the surface on the earth with a substantially less complex mechanism. In Carlson, a lamp and interior baffle rotate once every 24 hours with respect to the globe to simulate a day/night illumination pattern through a semi-transparent globe shell. As is well know, the actual day/night pattern of the surface of the earth oscillates through ± 23.5 degrees with respect to the polar axis as the earth completes a circumrevolution about the sun. In order to avoid the complexities of devices such as those described by Schulse, Carlson employs an adjustable cam mechanism by way of an exterior knob and flexible cable. Adjustment of the knob rocks the baffle back and forth about an axis passing through the equator of the model to simulate the seasonal variation of the light pattern on the globe. Although Carlson's mechanism is substantially less complex than many prior art devices, the device is believed to nevertheless remain excessively complex to succeed in the marketplace.

Whereas Carlson's and Schulse's devices described above are completely automatic (i.e. motor driven) others have attempted to avoid complexity by combining a completely manually driven globe simulating the day/night

illumination pattern on the earth. The device disclosed by Gardin in U.S. Patent No. 3,305,946 is intermediate in complexity between Schulse and Carlson in that adjustment of a single time of day ring, and day of year ring is sufficient to position an internal lamp with baffle appropriately to simulate the correct day/night pattern on the surface of the globe for a given time of day and year. Nevertheless, Gardin's mechanism still employs a plurality of beveled gears, counter-rotating shafts, etc. and has not found commercial acceptance in the marketplace. Other examples of day/night illuminating globes are provided by Veazey in U.S. Patent No. 4,102,121, Do en in U.S. Patent No. 4,714,351 and Mariotti in U.S. Patent No. 3,197,893. In each of the devices described in these patents, a different mechanism is employed to impart an appropriate "nodding" motion to an internal baffle to simulate the effect of the earth's orbit about the sun on a simulated day/night pattern for their globes. In each case, the mechanisms are complex and do not lend themselves to inexpensive production techniques.

Therefore, a need exists for a world globe model which indicates a day/night demarkation on the surface of the globe model with a simple, reliable and inexpensive mechanism. A need also exists for a globe model which simulates a day/night illumination pattern with a simple, reliable and economical mechanism.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a day/night globe or other planetary model which indicates a day/night demarkation on the globe's surface with a simple, reliable and economical mechanism.

It is a further object of the invention to provide an illuminated day/night planetary model which simulates both the rotation of the model with respect to the sun, and the

orbit of the model with respect to the sun in a mechanism which is simple, reliable and inexpensive to manufacture. The invention achieves these and other objects and advantages which will become apparent in the description which follows by providing a sphere for representing the planetary surface. The sphere is supported by a substantially equatorial support annulus located substantially parallel to an equatorial plane of the sphere. The support annulus is pivotally connected to a frame on a seasonal axis within the equatorial plane. A seasonal adjustment mechanism is journaled for rotation with the support annulus so that adjustment thereof places the polar axis of the sphere at an appropriate declination for a given month. A rotational mechanism is employed for rotating a day/night demarkation on the surface of the sphere approximately once each day so that by setting the seasonal adjustment mechanism appropriately and rotating the day/night demarkation on the sphere, a substantially correct day/night demarkation for a given time of year and local time of day is produced. The sphere thus being substantially equitorially supported, and the equatorial support being pivoted to provide the polar axis (or equitorial plane) with the correct declination with respect to an imaginary ecliptic plane, this day/night cycle can be simulated by a relatively simple mechanism.

In a preferred embodiment of the invention, the sphere is substantially hollow and semi-transparent and the rotating mechanism includes an internal light source mounted on an internal baffle. A motor fixed to the frame rotates the baffle with respect thereto (and with respect to the sphere) while the sphere "nods" through an angle of ± 23.5 degrees according to the setting of the seasonal adjustment mechanism. In this manner, approximately one- half of the sphere is bathed in simulated sunlight, and the remaining half is in simulated darkness for a given local time of day and month of year.

Rotation of the baffle by the motor simulates the motion of the sun across the surface of the sphere. An aperture, in the southern polar region of the sphere subtending an angle of approximately 47 degrees allows an axle to connect the motor with the rotating baffle throughout the seasonal "nodding" motion of the sphere by adjustment of the seasonal adjustment mechanism. A substantially opaque, boot can fill the aperture to prevent leakage of light from inside the sphere through the aperture.

In an alternate embodiment of the invention, the internal baffle and light source are replaced by an external arch connected to the frame which subtends at least an upper hemisphere of the planetary model. In this embodiment, a motor rotates the globe with respect to the frame beneath the arch. One side of the arch is provided with a day indicator (i.e. white paint) while the remaining side is provided with a night indicator (i.e. black paint) . As the globe rotates beneath the arch, the "day" portion of the globe is indicated on the "day" side of the arch while the "night" portion of the sphere is indicated beneath the "night" portion of the arch. In this alternate embodiment, the seasonal adjustment mechanism is set as in the preferred embodiment so that the planetary model has the correct polar/equitorial declination with respect to the arch for any given month of the year.

A time calculating ring can be positioned on top of the equatorial support annulus to permit calculation of time differences at various longitudes on the planetary model.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is an isometric view of a day/night globe employing the invention.

Figure 2 is a side elevational view of the globe shown in Figure 1.

Figure 2A is an enlarged, elevational view of circled area 2A in Figure 2. Figure 3 is a cross-sectional view taken along line 3-3 of Figure 1.

Figure 4 is an enlarged, partial, sectional view of circled area 4 in Figure 3.

Figure 5 is a sectional view taken along line 5-5 of Figure 3.

Figure 6 is a top plan view of a time calculation ring employable with either the preferred or alternate embodiment of the invention.

Figure 7 is an isometric view of an alternate embodiment of the invention.

Figure 8 is an isometric view of a second, alternate embodiment of the invention.

Figure 9 is a side elevational view, of the alternate embodiment shown in Figure 8. Figure 10 is an exploded isometric view of a motor and arcuate mechanism for use with the second alternate embodiment.

Figure 11 is a side elevational view of the motor and arcuate track mechanism of Figure 10.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A sunlit world globe, in accordance with the principles of the present invention is generally indicated at Reference Numeral 10 in Figure 1. The globe simulates the day/night appearance of the earth as seen from space with a simple, reliable and econo ical-to-manufacture mechanism as will be described further hereinbelow. As used herein, the terms "globe", "sphere", and "planetary model" are deemed interchangeable. Although the embodiments shown in the figures represent the planet earth, the structures and mechanisms described herein can

substantially equitorial support ring 18 which is in contact with the shell 12. A seasonal adjustment mechanism generally indicated at reference numeral 20 pivotally interconnects the equatorial support ring 18 and the frame 16 so that a substantially vertical polar axis (reference numeral 22 in Figs. 2 and 5) can be set with the appropriate declination for the month of the year.

As best seen in Figures 3 and 5, the shell is provided with an interior baffle 24 having an interior diameter approximately equal to the diameter of the shell 12. The interior baffle supports a conventional lamp or lamp 26 for illuminating one half of the shell. The baffle can be totally reflective but is preferably semi- transparent so that both hemispheres of the shell are illuminated with the "day" side more brightly illuminated than the "night" side.

A conventional, 60 Hz synchronous electric clock motor (not shown) is contained in a motor housing 28 and drives the baffle 24 and lamp 26 about a vertical axis defined by an axle 30 (see Fig. 5) once every approximately 24 hours. The synchronous clock motor 28 includes a 2:1 reduction gear mechanism of conventional design to convert the motor which completes one revolution every 12 hours into a 24-hour cycle clock. Preferably, the reduction ratio is slightly less then 2 : 1 so that the baffle revolves once every 23 hours, 56 minutes and 4.9 seconds to simulate sidereal time. If it is preferred to have the globe 10 simulate solar time, then a reduction ratio of 2 : 1 will suffice. The motor housing 28 is fixed to the frame 16 by brackets 32 and screws 33 against translational and rotational movement.

A conventional alternating current cord 34 powers the motor in housing 28 with conventional house current. The lamp 26 communicates with inverting circuitry (not shown) of conventional design in the motor housing 28 through a power line 36. The circuitry is entirely of the conventional AC/DC converting type employing a step-down

transformer, diode bridge, smoothing capacitor and resistor to convert the 60 Hz household current to 12 volt direct current. The lamp 26 can therefore be any variety of conventional 12 volt DC bulb selected for desired brightness.

The shell 12 is manufactured in northern and southern hemispheres 38, 40 joined by a frictional engagement lip 44. The northern hemisphere has a downwardly depending portion 46 which engages a concavity 48 in the southern hemisphere in an interference fit so that the hemispheres do not become inadvertently dislodged. This construction is simple, inexpensive and facilitates access to rotating baffle 24 and lamp 26. The southern hemisphere 40 has a substantially circular aperture 42 subtending an angle of approximately 47 degrees with respect to the center of the sphere. This aperture allows the shell 12 to "nod" with respect to the frame 16 through an angle of ± 23.5 degrees to simulate the position of the earth's polar axis with respect to the ecliptic plane throughout the earth's orbit about the sun. A rubber boot 43 substantially seals the aperture and permits the axle 30 and power line 36 to pass therethrough. The rubber boot has a small opening therein to permit relative rotation of the sphere with respect to the axle and the power cord. The power cord 36 communicates with the hereinabove described AC/DC converting circuitry by way of conventional slip rings (not shown) in the motor housing 28 such as those described by Carlson in U.S. Patent No. 4,936,779, the disclosure of which is incorporated herein by reference. The southern hemisphere also has a radially outwardly directed, circumferential lip 50, best seen in Figure 4 which is received in a corresponding, concavity 52 in the equatorial support ring 18. The support ring 18 comprises an upper annulus 54 having a substantially smooth, lower bearing surface which is slidable with respect to a lower annulus 56. The upper annulus 54 has an interior diameter which is substantially equal to the

diameter of the spherical shell 12 and an outer diameter which is somewhat smaller than the horizontal distance between the inner sides of frame uprights 58, 60. The lower annulus 56 is journaled by pivot pins 62, 64 to the frame uprights 58, 60. The inner diameter of the lower annulus is somewhat larger than the diameter of the spherical shell 12. Thus, the sphere which is fixed to the upper annulus can rotate with respect to the frame 16 because the upper annulus rotatably supports the lower annulus. Thus the sphere 12 can be rotated manually with respect to the baffle 24 and motor housing 28 without complicated clutch mechanisms, differentials, etc. Simultaneously, the sphere and equatorial support ring 18 can pivot as a unit with respect to the frame 16 about the substantially equatorial axis defined by pivot pins 62, 64 which is perpendicular to the polar axis 22 in Figures 2 and 5.

It should be apparent that by displacing the equatorial support ring as shown in Figure 2 from the horizontal position shown in solid lines, the polar axis 22 can be inclined or declined by 23.5 degrees to either the left or the right to simulate the position of the earth's polar axis with respect to the ecliptic plane (represented by the floor on which the frame 16 rests) at various times of the year. For this purpose, the globe is preferably provided with the seasonal adjustment mechanism 20 as shown in Figure 2 and in detail in Figure 2A. The seasonal adjustment mechanism includes a pointer 66 journaled for rotation with pivot pin 64. The mechanism is also provided with a scale 68 shown in Figure 2A having demarcations by month, the months having the summer and winter solstices (June and December) in the center of the scale and the months having the vernal and autumnal equinox (March and September) at far ends of the scale. The pivot pin 62 (which is diametrically opposed from pivot pin 64 - see Fig. 4) is provided with threads 70 so that a wing nut 72 can be tightened against a washer 74

with respect to the frame upright 58 to fix the setting of the pointer 66 for the appropriate month of the year. After setting the pointer appropriately, the sphere 12 can be synchronized with respect to the internal baffle 24 to simulate the correct day/night pattern on the sphere's surface for the appropriate time of day. Such synchronization is easily accomplished. As previously stated, the sphere 22 and upper annulus 54 connected thereto can rotate with respect to the lower annulus 56 and frame 16. The user merely plugs in the motor (which begins rotating the baffle 24 at a slow speed, and illuminates the lamp 26) and then manually rotates the sphere with respect to the baffle until the day/night demarkation 76 is at the correct position for the current time of day while the pointer 66 is positioned on the current month. As long as the sphere is not rotated with respect to the frame, the baffle will remain synchronized as the user adjusts the pointer 66 for different months of the year. The frame 16 can be provided with conventional casters (not shown) to translate or rotate the entire glove 10 with respect to the floor.

Figure 6 illustrates a substantially transparent time ring 80 having demarcations in the form of post meridian and ante meridian power markings. The ring is dimensioned so as to reside on top of the upper annulus 54. A knob 84 is fixed to the time ring and permits the user to align the current time demarcations with his local longitude. The remaining demarkation shows the corresponding time at other latitudes around the sphere. Figure 7 is an alternate embodiment of the invention generally indicated at reference numeral 100. This embodiment utilizes many of the structures of the preferred embodiment shown in Figures 1-6 with like elements bearing identical reference numerals. In this embodiment, interior baffle 24, internal lamp 26, aperture 42 and rubber boot 43 are eliminated and are replaced by

a day/night arch 112 connected to the uprights 58, 60 of the frame 16.

One side 114 of the arch 112 is painted white to represent the "day" side of the globe 100. The remaining side 116 is painted black to represent the "night" side. In this embodiment, the motor in motor housing 28 rotates the shell 12 with respect to the frame 16 and arch 114. The arch preferably at least circumscribes the northern hemisphere of the sphere, and can be provided with right and left (not shown) continuation portions 118 to demarcate the "day" and "night" sides of the southern hemisphere. The arch 112 is thus fixed to the frame while the sphere 12 rotates thereunder. To accommodate the oscillation of the sphere 12 and motor housing 28 about the equatorial axis 120 defined by the pivot pins 62, 64 the brackets 32 in this embodiment are fixed to the frame 16 but are not fixed to the motor housing 28. In the preferred embodiment, as best seen in Figure 3, the brackets 32 are provided on both the right hand and left hand sides of the motor housing 28 and are fixed to both the frame and the motor. In this alternate embodiment 100, the brackets are only fixed to the frame. A small clearance is established between the brackets and the motor housing. The motor housing is thus free to swing in an arcuate movement through ± 23.5 degrees while the brackets restrict rotation of the motor with respect to the frame.

Both embodiments, while elegant in their simplicity accurately depict a day/night demarkation on the earth's surface. Each embodiment has a minimum of moving parts, is simple to manufacture and is extremely rugged. Those of ordinary skill in the art will perceive other embodiments which although not described in detail here will be obvious variations thereof. These other embodiments are considered to fall within the scope of this disclosure.

A second alternate embodiment, is generally indicated at reference numeral 130 in Figures 8 and 9. This second alternate embodiment shares various structural features in common with the previously described embodiments wherein like reference numerals represent like structures. That is, in this second alternate embodiment, the invention employs a semi-transparent shell 12 having planetary features 14, a polar axis 22, and an interior rotating baffle 24 supporting a light bulb 26 as in the previous embodiments. A 60 Hz synchronous motor housing 28 and drive axle 30 as best seen in Figures 10 and 11 perform the same function as in the previous two embodiments, that is rotating the baffle with respect to the sphere once every 24 hours. However in this embodiment, a crescent- shaped frame 132 supports the globe in a fixed relationship with respect to a base 134 at the north pole 136 of the shell 12. The shell in this alternate embodiment has the same aperture 42 subtending an angle of approximately 47° in the southern hemisphere as does the previous two embodiments. However, in this second, alternate embodiment rather than the sphere nodding about a equatorial axis transverse to the polar axis 22 (as in the preferred embodiment) , the sphere is fixed with respect to the base 134 while the baffle itself nods about a transverse, equatorial axis by motion of the motor housing 28 along an arcuate path as depicted by dash lines 30' displaying the axle 30 positions indicative of the summer solstice and vernal equinox.

As best seen in Figures 10 and 11, the motor housing 28 rides on an arc-shaped track 138 within the base 134. The motor housing has a protruding leg 140 supporting a roller bearing 142 which rides in a trough 143 defined by the track. The track has its center of curvature coincident with the center of the semi-transparent shell 12 causing the baffle to pivot as previously described about a transverse equatorial axis. A stabilizing track 138' can be provided for supplemental support of the motor

housing 28 through runners 138". The base 134 is also provided with a rack 144 which engages a pinion gear 146 journaled for rotation with respect to the motor housing 28. A control knob 140 is connected to pinion gear 146 by shaft 149. Control knob 148 can be manually rotated engaging the pinion 146 with the rack 144 causing the motor housing to translate on the track 142. This action causes the baffle 24 to pivot as previously described. The base 134 is provided with slots 150, 152 to permit the axle 30 and shaft 149 to move without obstruction by the base.

An indicator mechanism or pointer 154 is provided on the motor housing. The pointer protrudes through a third slot 156 in the base 134 to indicate the relative position of the motor on the track with respect to the base. A monthly scale 158 is provided on the base adjacent to the pointer to indicate the month corresponding to the declination of the baffle 24 with respect to the shell 12. As previously stated, the outermost positions of the pointer on the scale correspond to the summer solstice and vernal equinox (shown in dotted lines by the position of axle 30') while the baffle when in the solid line position shown by axle 30 corresponds to the spring and autumnal equinoxes. As will be apparent to those of ordinary skill in the art, by energizing the motor with a motor housing 28 as previously described, the baffle will rotate and the light 26 will be illuminated simulating the path of the sun across the face of the earth due to the earth's rotation. Adjustment of the control knob 148 will cause the baffle 24 to nod simulating the declination of the ecliptic plane with respect to the equatorial plane of the sphere for the appropriate month of year as indicated by the pointer 154. It will also be apparent to those of ordinary skill in the art, that one could achieve the same result by fixing the motor housing 28 to the base 134 and causing the shell 12 to pivot about a horizontal transverse axis as previously

described. This can be achieved by causing the frame 132 to ride in the track 142 rather than the motor housing and employing the appropriate rack and pinion mechanism so as to allow a user to set the position of the same with respect to the base on this arcuate path.

Therefore, the invention is not to be limited by the description above, but determined in scope by the claims which follow.