Cycloid polar sundial and manufacturing method thereof

Abstract

The present invention provides a cycloid polar sundial and a method for making the same. The cycloid polar sundial includes a cycloid polar plate, a morning time scale plate, a afternoon time scale plate, and a cycloid plate. The cycloid polar plate is supported on a latitude support. The cycloid polar plate is provided with a morning time cutout, a morning time geographic longitude scale, an afternoon time cutout, and an afternoon time geographic longitude scale. The morning time scale plate is fixed within the morning time cutout, and the afternoon time scale plate is fixed within the afternoon time cutout. The cycloid plate is vertically mounted on the cycloid polar plate. The cycloid plate is a circular cycloid surface, with the circular cycloid of the cycloid plate facing the side of the cycloid polar plate, and the center of its bottom is fixed between the morning time cutout and the afternoon time cutout. The present invention simulates the changes in shadows of points on the Earth under sunlight based on the Earth's rotation, thereby realistically reflecting the changes in motion between the Earth and the Sun.

Description

Technical Field

[0001] The present invention relates to the technical field of sundials, and in particular to a cycloid polar sundial and a manufacturing method thereof. Background Art

[0002] A sundial, also known as a sundial, is a device that indicates the hour or minute based on the position of the sun's shadow. Traditional Chinese sundials are equatorial sundials. Ancient Chinese people, through long-term research, discovered that when the dial is parallel to the equator, the shadow of the gnomon on the dial changes at a uniform rate.

[0003] The principle of an equatorial sundial is to treat the Earth as a fixed point and interpret the motion between the Sun and the Earth as the Sun's rotation around the Earth. This simplifies the sun's undulating motion around the gnomon. During the periods of the spring equinox, summer solstice, and autumnal equinox, the time is displayed on the upper surface of the sundial plate, while during the periods of the autumnal equinox, winter solstice, and spring equinox, the time is displayed on the lower surface. On the spring and autumnal equinoxes, the sun's rays are parallel to the sundial plane, so the gnomon casts no shadow on the plane. Therefore, an equatorial sundial does not operate on these days.

[0004] The time of half a year on an equatorial sundial is displayed on the back of the sundial disk, so the equatorial sundial needs to be set up at a higher place to make it easier for the observer to read the value on the back of the sundial disk.

[0005] Given that the equatorial sundial is based on the geocentric theory (the Earth-centered sun-Earth motion), which contradicts the Earth's rotation around the Sun, it cannot truly reflect the changes in the motion between the Earth and the Sun. Furthermore, in popular science education, it is very abstract to ask primary and secondary school students to think in reverse order to understand the Sun's rotation around the Earth. Summary of the Invention

[0006] In response to the defects in the prior art, the present invention provides a cycloid polar sundial and a method for manufacturing the same. The cycloid polar sundial is based on the rotation of the earth and simulates the changes in the shadow of a point on the earth under sunlight, thereby truly reflecting the changes in the movement between the earth and the sun.

[0007] In one aspect, the present invention provides a cycloid polar sundial comprising:

[0008] A cycloid sundial polar plate, the cycloid sundial polar plate being supported on a latitude support member and parallel to the polar axis; a morning time cutout region being provided on the eastern side of the cycloid sundial polar plate, and a morning time geographic longitude scale being provided along the morning time cutout region; and an afternoon time cutout region being provided on the western side of the cycloid sundial polar plate, and a afternoon time geographic longitude scale being provided along the afternoon time cutout region;

[0009] A morning time scale plate, wherein the morning time scale plate is provided with a morning time scale, the morning time scale plate is cut to a size suitable for the morning time cutting area and fixed in the morning time cutting area, and the 12 o'clock on the morning time scale is aligned with the local geographical longitude corresponding to the morning time geographical longitude scale;

[0010] an afternoon time scale plate, the afternoon time scale plate being provided with afternoon time markings, the afternoon time scale plate being cut to a size suitable for the afternoon time cutting area and being fixed within the afternoon time cutting area, and the 12 o'clock on the afternoon time markings being aligned with the local geographic longitude corresponding to the afternoon time geographic longitude scale;

[0011] A cycloid sundial plate is parallel to the equatorial plane and mounted vertically on the cycloid sundial polar plate. The cycloid sundial plate is a circular cycloid surface, the circular cycloid of the cycloid sundial plate faces the side of the cycloid sundial polar plate, and the center of its bottom is fixed between the morning time cutting area and the afternoon time cutting area.

[0012] Furthermore, the latitude support comprises two latitude plates fixed vertically in the north-south direction on the lower side of the cycloid sundial polar plate and supported on a horizontal plane. The latitude plates are fan-shaped plates, the central angle of which is equal to the local geographic latitude and faces north.

[0013] Furthermore, a first clamping protrusion is provided on the upper side of the latitude plate, and first clamping grooves are respectively provided at both ends of the cycloid sundial polar plate, and the first clamping protrusions on each latitude plate are respectively clamped to the first clamping grooves at the corresponding ends of the cycloid sundial polar plate.

[0014] Furthermore, the latitude plate is cut from a right-angled sector plate marked with geographic latitude scales.

[0015] Furthermore, the morning time scale plate is provided with two rows of morning time scales respectively located on both sides of the cycloid sundial plate, and the afternoon time scale plate is provided with two rows of afternoon time scales respectively located on both sides of the cycloid sundial plate.

[0016] Furthermore, the cycloid sundial polar plate is provided with a plurality of positioning and mounting baffles which are respectively located around the morning time cutting area and the afternoon time cutting area and are tilted upwards. The morning time scale plate is positioned in the middle of the positioning and mounting baffles around the morning time cutting area, and the afternoon time scale plate is positioned in the middle of the positioning and mounting baffles around the afternoon time cutting area.

[0017] Furthermore, the cycloid sundial plate is formed by folding a circular cycloid plate with circular cycloids on both sides along a center line.

[0018] Furthermore, a second snap-in protrusion is provided in the middle of both sides of the circular cycloid plate. When the circular cycloid plate is folded along the center line into a cycloid sundial plate, the second snap-in protrusions on both sides overlap. The cycloid sundial polar plate is provided with a second snap-in groove extending along the length direction between the morning time cutting area and the afternoon time cutting area. The two overlapping second snap-in protrusions at the bottom of the cycloid sundial plate are snapped into the second snap-in groove together.

[0019] Furthermore, a third clamping groove is symmetrically provided on both sides of the folding center line in the middle of the circular cycloid plate. When the circular cycloid plate is folded along the center line into a cycloid sundial plate, the third clamping grooves on both sides coincide with each other. A fourth clamping groove is provided on both sides of the second clamping groove on the cycloid sundial polar plate. Both sides of the cycloid sundial plate are provided with right-angled triangular support plates, and two right-angled sides of the right-angled triangular support plates are respectively provided with a third clamping protrusion and a fourth clamping protrusion. The third clamping protrusion on each right-angled triangular support plate is respectively clamped to the third clamping groove on the corresponding side of the cycloid sundial plate, and the fourth clamping protrusion on each right-angled triangular support plate is respectively clamped to the fourth clamping groove on the corresponding side of the cycloid sundial polar plate.

[0020] In another aspect, the present invention provides a method for manufacturing a cycloid polar sundial, wherein the components required for the cycloid polar sundial are integrated on a cardboard by die-printing, comprising the following steps:

[0021] Step S10: removing two rectangular sector plates marked with geographic latitude scales from the printed cardboard, and cutting the rectangular sector plates into latitude plates according to the local geographic latitude, so that the central angle of the latitude plate is equal to the local geographic latitude;

[0022] Step S20: Remove the cycloid sundial polar plate, the morning time scale plate, and the afternoon time scale plate from the printed cardboard, align the 12 o'clock mark on the morning time scale plate with the local geographic longitude corresponding to the morning time geographic longitude scale, and then trim the morning time scale plate at both ends with reference to the range of the morning time cutting zone. Simultaneously, align the 12 o'clock mark on the afternoon time scale plate with the local geographic longitude corresponding to the afternoon time geographic longitude scale, and then trim the afternoon time scale plate at both ends with reference to the range of the afternoon time cutting zone.

[0023] Step S30, assembling the two cut latitude plates on the lower sides of the two ends of the polar plate of the cycloid sundial;

[0024] Step S40, installing the morning time scale plate in the morning time cutting area, and installing the afternoon time scale plate in the afternoon time cutting area;

[0025] Step S50: Remove the cycloid sundial plate and the two right-angled triangular support plates from the printed cardboard, fold the cycloid sundial plate in half along the dotted line, and then install the two right-angled triangular support plates on both sides of the cycloid sundial plate.

[0026] Step S60 , installing the cycloid sundial plate assembled in step S50 on the cycloid sundial polar plate assembled in step S40 .

[0027] The beneficial effects of the present invention are embodied in:

[0028] The present application utilizes the property that the shadow cast by sunlight and the cycloid plane on a plane parallel to the polar axis changes uniformly in a straight line to create a cycloid polar sundial that can be used in all regions. The morning and afternoon time scales corresponding to the shadow cast by the sun on the cycloid polar plate can be observed to read the longitude-corrected sundial time. The cycloid polar sundial is based on the rotation of the earth and simulates the changes in the shadow of a point on the earth under sunlight, thereby truly reflecting the changes in the movement between the earth and the sun, and can clearly explain the movement relationship between the sun and the earth. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly describes the drawings required for the specific embodiments or the description of the prior art. Similar elements or parts are generally identified by similar reference numerals throughout the drawings. Elements or parts in the drawings are not necessarily drawn to scale.

[0030] Figure 1 This is a schematic diagram of a paperboard according to a first embodiment of the present invention;

[0031] Figure 2 is a schematic diagram of another paperboard according to an embodiment of the present invention;

[0032] Figure 3 Schematic diagram of a cutout of a latitude plate according to an embodiment of the present invention;

[0033] Figure 4 This is a cutaway diagram of the morning time scale plate according to an embodiment of the present invention;

[0034] Figure 5 This is a cutaway diagram of the afternoon time scale plate according to an embodiment of the present invention;

[0035] Figure 6 Schematic diagram of the assembly of the latitude plate and the polar plate of the cycloid sundial according to an embodiment of the present invention;

[0036] Figure 7 Schematic diagram of the morning time scale plate and the afternoon time scale plate assembled on the polar plate of a cycloid sundial according to an embodiment of the present invention;

[0037] Figure 8 Schematic diagram of the assembly of the cycloid sundial plate and the right-angled triangular support plates on both sides according to an embodiment of the present invention;

[0038] Figure 9This is a schematic diagram of the completed assembly of an embodiment of the present invention;

[0039] Figure 10 This is a schematic diagram of reading a sundial according to an embodiment of the present invention.

[0040] In the accompanying drawings, 100-cycloid sundial polar plate; 110-morning time cutting area; 120-morning time geographical longitude scale; 130-afternoon time cutting area; 140-afternoon time geographical longitude scale; 150-first slot; 160-positioning mounting baffle; 170-second slot; 180-fourth slot; 200-morning time scale plate; 210-morning time scale; 300-afternoon time scale plate; 310-afternoon time scale; 400-cycloid sundial plate; 410-second snap-fit ​​protrusion; 420-third slot; 500-latitude plate; 510-first snap-fit ​​protrusion; 520-geographical latitude scale; 600-right-angle triangle support plate; 610-third snap-fit ​​protrusion; 620-fourth snap-fit ​​protrusion. DETAILED DESCRIPTION

[0041] The following embodiments of the technical solution of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and are therefore only examples and are not intended to limit the scope of protection of the present invention.

[0042] It should be noted that, unless otherwise specified, the technical or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0043] The embodiment of the present invention provides a cycloid polar sundial, such as Figure 1 and Figure 2 As shown, the parts required for the cycloid polar sundial are integrated on the cardboard in a die-printed manner, and all parts can be removed from the cardboard by simple cutting.

[0044] Reference Figure 3-Figure 10 The cycloid polar sundial includes a cycloid polar plate 100 , a morning time scale plate 200 , a afternoon time scale plate 300 and a cycloid sundial plate 400 .

[0045] The cycloid sundial polar plate 100 is supported on the latitude support member, and the cycloid sundial polar plate 100 is parallel to the polar axis.

[0046] Reference Figure 3 and Figure 6 The latitude support includes two latitude plates 500 fixed vertically along the north-south direction on the lower side of the cycloid sundial polar plate 100 and supported on a horizontal plane. The latitude plates 500 are fan-shaped plates. The central angle of the latitude plates 500 is equal to the local geographic latitude and faces north. In this way, the cycloid sundial polar plate 100 can be ensured to be parallel to the polar axis during installation.

[0047] In order to facilitate the connection and fixation between the latitude plate 500 and the cycloid sundial polar plate 100, a first snap-fitting protrusion 510 is provided on the upper side of the latitude plate 500, and a first snap-fitting groove 150 is provided at each end of the cycloid sundial polar plate 100. The first snap-fitting protrusion 510 on each latitude plate 500 is snap-fitted to the first snap-fitting groove 150 at the corresponding end of the cycloid sundial polar plate 100.

[0048] In this embodiment, the latitude plate 500 is cut from a rectangular sector plate marked with geographic latitude scale 520. For example, if the geographic latitude of the observation site is 30 degrees north latitude, the latitude plate 500 is cut from a rectangular sector plate marked with geographic latitude scale 520. Figure 3 It is cropped as shown so that it can be used in different latitudes.

[0049] A morning time cutout region 110 is provided on the east side of the cycloid sundial polar plate 100 , and a morning time geographic longitude scale 120 is provided along the morning time cutout region 110 . An afternoon time cutout region 130 is provided on the west side of the cycloid sundial polar plate 100 , and a afternoon time geographic longitude scale 140 is provided along the afternoon time cutout region 130 .

[0050] Reference Figure 7 The morning time scale plate 200 is provided with a morning time scale 210. The morning time scale plate 200 is cut into a size suitable for the morning time cutting area 110 and fixed in the morning time cutting area 110, and the 12 o'clock on the morning time scale 210 is aligned with the corresponding local geographic longitude on the morning time geographic longitude scale 120.

[0051] The afternoon time scale plate 300 is provided with an afternoon time scale 310. The afternoon time scale plate 300 is cut to a size suitable for the afternoon time cutting area 130 and fixed in the afternoon time cutting area 130. The 12 o'clock on the afternoon time scale 310 is aligned with the corresponding local geographic longitude on the afternoon time geographic longitude scale 140.

[0052] like Figure 4 As shown, when the morning time scale plate 200 is cut, if the local geographic longitude is 110 degrees east longitude, align the arrow at 12 o'clock on the morning time scale 210 with the 110-degree longitude line on the morning time geographic longitude scale 120, and then cut off the parts of the two ends of the morning time scale plate 200 that exceed the morning time cutting area 110.

[0053] like Figure 5 As shown, when the afternoon time scale plate 300 is cut, if the local geographic longitude is 110 degrees east longitude, align the arrow at 12 o'clock on the afternoon time scale 310 with the 110-degree longitude line on the afternoon time geographic longitude scale 140, and then cut off the parts of the two ends of the afternoon time scale plate 300 that exceed the afternoon time cutting area 130.

[0054] Reference Figure 6 and Figure 7 The cycloid sundial polar plate 100 is provided with a plurality of upwardly tilted positioning baffles 160 respectively located around the morning time cut-out area 110 and the afternoon time cut-out area 130. The morning time scale plate 200 is positioned in the middle of the positioning baffles 160 around the morning time cut-out area 110, and the afternoon time scale plate 300 is positioned in the middle of the positioning baffles 160 around the afternoon time cut-out area 130.

[0055] When installing the morning time scale plate 200 and the afternoon time scale plate 300, the morning time scale plate 200 can be positioned and installed in the morning time cut-out area 110, and the afternoon time scale plate 300 can be positioned and installed in the afternoon time cut-out area 130 through the positioning installation baffle 160 on the cycloid sundial polar plate 100. During installation, it is necessary to ensure that the arrow at 12 o'clock on the morning time scale plate 200 is aligned with the local geographical longitude on the morning time geographical longitude scale 120, and the arrow at 12 o'clock on the afternoon time scale plate 300 is aligned with the local geographical longitude on the afternoon time geographical longitude scale 140. In this way, the longitude time difference can be adjusted and it is applicable to different longitude areas.

[0056] The cycloid plate 400 is parallel to the equatorial plane and mounted vertically on the cycloid polar plate 100. The cycloid plate 400 is a circular cycloid surface, with the circular cycloid of the cycloid plate 400 facing the side of the cycloid polar plate 100, and the center of its bottom is fixed between the morning time cutting area 110 and the afternoon time cutting area 130.

[0057] Reference Figure 1 The cycloid sundial plate 400 is formed by folding a cycloid plate with cycloids on both sides along the center line.

[0058] Reference Figure 7 and Figure 8 A second snap-fitting protrusion 410 is provided in the middle of both sides of the circular cycloid plate. When the circular cycloid plate is folded along the center line to form the cycloid sundial plate 400, the second snap-fitting protrusions 410 on both sides overlap. The cycloid sundial polar plate 100 is provided with a second snap-fitting groove 170 extending along the length thereof between the morning time cutout area 110 and the afternoon time cutout area 130. The two overlapping second snap-fitting protrusions 410 at the bottom of the cycloid sundial plate 400 are snapped into the second snap-fitting groove 170 together, thereby facilitating the fixed installation of the cycloid sundial plate 400 on the cycloid sundial polar plate 100.

[0059] Preferably, the middle of the circular cycloid plate is symmetrically provided with third clamping grooves 420 on both sides of the folding center line. When the circular cycloid plate is folded along the center line into the cycloid sundial plate 400, the third clamping grooves 420 on both sides overlap. The cycloid sundial polar plate 100 is provided with fourth clamping grooves 180 on both sides of the second clamping groove 170. Both sides of the cycloid sundial plate 400 are provided with right-angled triangular support plates 600. The two right-angled sides of the right-angled triangular support plates 600 are respectively provided with third clamping protrusions 610 and fourth clamping protrusions 620. The third clamping protrusions 610 on each right-angled triangular support plate 600 are respectively clamped to the third clamping grooves 420 on the corresponding side of the cycloid sundial plate 400, and the fourth clamping protrusions 620 on each right-angled triangular support plate 600 are respectively clamped to the fourth clamping grooves 180 on the corresponding side of the cycloid sundial polar plate 100. The two sides of the cycloid plate 400 are stably supported by the right-angled triangular support plates 600, which not only improves the stability of the installation of the cycloid plate 400, but also prevents the cycloid plate 400 from swinging left and right, ensuring that the cycloid plate 400 is perpendicular to the cycloid polar plate 100.

[0060] During use, the cycloid polar plate 100 is perpendicular to the equatorial plane, and the cycloid pole is parallel to the equatorial plane. The shadow of the cycloid plate 400 on the cycloid polar plate 100 is observed. If it is morning, the time indicated by the shadow of the cycloid plate 400 on the morning time scale plate 200 is read. If it is afternoon, the time indicated by the shadow of the cycloid plate 400 on the afternoon time scale plate 300 is read. In this way, the local sundial time corrected for longitude can be known. Figure 10 The sundial time shown is 11 o'clock. Then you can convert Beijing time = sundial time + true mean time difference. The true mean time difference is found in the table according to the month of observation.

[0061] The present invention is based on the rotation of the earth and simulates the changes in the shadow of a point on the earth under the illumination of sunlight. When the earth rotates, the trajectory of a point on the earth is a "cycloid". Starting from the point on the morning horizon at 6 o'clock, at 12 noon, it is equivalent to the morning point having traveled 90 degrees on the circular surface line. If this cycloid is used as the sundial, the projection of the shadow generated by the sunlight and the cycloid surface on the surface parallel to the polar axis will change uniformly in a straight line.

[0062] Therefore, the present application utilizes the characteristic that the shadows cast by sunlight and the cycloid plane on a plane parallel to the polar axis are projected in a straight line and uniformly change, to manufacture a cycloid polar sundial that can be used in all regions. The morning time scale 210 and the afternoon time scale 310 corresponding to the shadows cast by the sun on the cycloid polar plate 100 can be observed to read the sundial time after longitude correction. The cycloid polar sundial is based on the rotation of the earth and simulates the changes in the shadows of points on the earth under sunlight, thereby truly reflecting the changes in the movement between the earth and the sun, and can clearly explain the movement relationship between the sun and the earth.

[0063] Preferably, the morning time scale plate 200 is provided with two rows of morning time scales 210, one on each side of the cycloid sundial plate 400, and the afternoon time scale plate 300 is provided with two rows of afternoon time scales 310, one on each side of the cycloid sundial plate 400. During the summer in the northern hemisphere, the shadow cast by sunlight on the cycloid sundial plate 400 is cast on the row of morning time scales 210 or afternoon time scales 310 on the south side. During the winter in the northern hemisphere, the shadow cast by sunlight on the cycloid sundial plate 400 is cast on the row of morning time scales 210 or afternoon time scales 310 on the north side. This makes it convenient to read the sundial time in different seasons.

[0064] An embodiment of the present invention further provides a method for manufacturing a cycloid polar sundial, wherein the components required for the cycloid polar sundial are integrated on a cardboard by die-stamping, and the method includes the following steps:

[0065] Step S10: remove two rectangular sector plates marked with geographic latitude scales 520 from the printed cardboard, and cut the rectangular sector plates into latitude plates 500 according to the local geographic latitude, so that the central angle of the latitude plate 500 is equal to the local geographic latitude;

[0066] Step S20: Remove the cycloid sundial polar plate 100, the morning time scale plate 200, and the afternoon time scale plate 300 from the printed cardboard. Align the 12:00 mark on the morning time scale plate 200 with the local geographic longitude corresponding to the morning time geographic longitude scale 120. Then, cut the two ends of the morning time scale plate 200 with reference to the range of the morning time cutting area 110. Simultaneously, align the 12:00 mark on the afternoon time scale plate 300 with the local geographic longitude corresponding to the afternoon time geographic longitude scale 140. Then, cut the two ends of the afternoon time scale plate 300 with reference to the range of the afternoon time cutting area 130.

[0067] Step S30, assembling the two cut latitude plates 500 on the lower sides of the two ends of the cycloid sundial polar plate 100 respectively;

[0068] Step S40, installing the morning time scale plate 200 in the morning time cutting area 110, and installing the afternoon time scale plate 300 in the afternoon time cutting area 130;

[0069] Step S50: Remove the cycloid sundial plate 400 and the two right-angled triangular support plates 600 from the printed cardboard, fold the cycloid sundial plate 400 in half along the dotted line, and then install the two right-angled triangular support plates 600 on both sides of the cycloid sundial plate 400;

[0070] Step S60 , installing the cycloid sundial plate 400 assembled in step S50 on the cycloid sundial polar plate 100 assembled in step S40 .

[0071] The components required for the cycloid polar sundial are integrated on cardboard by die-stamping. All parts can be removed from the cardboard by simple cutting and then assembled according to the design. Its structure is simple and can be assembled by users themselves, making it easy to manufacture.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention.

Claims

1. A cycloid polar sundial, characterized in that: include: A cycloid sundial polar plate, the cycloid sundial polar plate being supported on a latitude support member and parallel to the polar axis; a morning time cutout region being provided on the eastern side of the cycloid sundial polar plate, and a morning time geographic longitude scale being provided along the morning time cutout region; and an afternoon time cutout region being provided on the western side of the cycloid sundial polar plate, and a afternoon time geographic longitude scale being provided along the afternoon time cutout region; A morning time scale plate, wherein the morning time scale plate is provided with a morning time scale, the morning time scale plate is cut to a size suitable for the morning time cutting area and fixed in the morning time cutting area, and the 12 o'clock on the morning time scale is aligned with the local geographical longitude corresponding to the morning time geographical longitude scale; an afternoon time scale plate, the afternoon time scale plate being provided with afternoon time markings, the afternoon time scale plate being cut to a size suitable for the afternoon time cutting area and being fixed within the afternoon time cutting area, and the 12 o'clock on the afternoon time markings being aligned with the local geographic longitude corresponding to the afternoon time geographic longitude scale; a cycloid sundial plate, the cycloid sundial plate being parallel to the equatorial plane and mounted perpendicularly on the cycloid sundial polar plate; the cycloid sundial plate being a circular cycloid surface, the circular cycloid of the cycloid sundial plate being oriented toward the polar plate, and the center of its bottom being fixed between the morning time cutting area and the afternoon time cutting area; The shadow cast by sunlight and the cycloid plane is projected onto a plane parallel to the polar axis in a straight line and changes evenly. Based on the shadow cast by the cycloid sundial plate on the polar plate of the cycloid sundial, if it is morning, the time indicated by the shadow cast by the cycloid sundial plate on the morning time scale plate is read; if it is afternoon, the time indicated by the shadow cast by the cycloid sundial plate on the afternoon time scale plate is read.

2. The cycloid polar sundial according to claim 1, wherein: The latitude support comprises two latitude plates fixed vertically in the north-south direction on the lower side of the cycloid sundial polar plate and supported on a horizontal plane. The latitude plates are fan-shaped plates, the central angle of which is equal to the local geographic latitude and faces north.

3. The cycloid polar sundial according to claim 2, wherein: A first clamping protrusion is provided on the upper side of the latitude plate, and first clamping grooves are respectively provided at both ends of the cycloid sundial polar plate. The first clamping protrusions on each latitude plate are respectively clamped into the first clamping grooves at the corresponding ends of the cycloid sundial polar plate.

4. The cycloid polar sundial according to claim 2, wherein: The latitude plate is cut from a right-angled sector plate marked with geographic latitude scales.

5. The cycloid polar sundial according to claim 1, wherein: The morning time scale plate is provided with two rows of morning time scales respectively located on both sides of the cycloid sundial plate, and the afternoon time scale plate is provided with two rows of afternoon time scales respectively located on both sides of the cycloid sundial plate.

6. The cycloid polar sundial according to claim 1, wherein: The cycloid sundial polar plate is provided with a plurality of upwardly tilted positioning and mounting baffles respectively located around the morning time cutting area and the afternoon time cutting area. The morning time scale plate is positioned in the middle of the positioning and mounting baffles around the morning time cutting area, and the afternoon time scale plate is positioned in the middle of the positioning and mounting baffles around the afternoon time cutting area.

7. The cycloid polar sundial according to claim 1, wherein: The cycloid sundial plate is formed by folding a circular cycloid plate with circular cycloids on both sides along a center line.

8. The cycloid polar sundial according to claim 7, characterized in that: A second snap-fitting protrusion is provided in the middle of both sides of the circular cycloid plate. When the circular cycloid plate is folded along the center line into a cycloid sundial plate, the second snap-fitting protrusions on both sides overlap. The polar plate of the cycloid sundial is provided with a second snap-fitting groove extending along the length direction between the morning time cutting area and the afternoon time cutting area. The two overlapping second snap-fitting protrusions at the bottom of the cycloid sundial plate are snapped into the second snap-fitting groove together.

9. The cycloid polar sundial according to claim 8, characterized in that: The middle of the circular cycloid plate is symmetrically provided with a third clamping groove on both sides of the folding center line. When the circular cycloid plate is folded along the center line into a cycloid sundial plate, the third clamping grooves on both sides overlap. The cycloid sundial polar plate is provided with a fourth clamping groove on both sides of the second clamping groove. Both sides of the cycloid sundial plate are provided with right-angled triangular support plates, and the two right-angled sides of the right-angled triangular support plates are respectively provided with a third clamping protrusion and a fourth clamping protrusion. The third clamping protrusion on each right-angled triangular support plate is respectively clamped to the third clamping groove on the corresponding side of the cycloid sundial plate, and the fourth clamping protrusion on each right-angled triangular support plate is respectively clamped to the fourth clamping groove on the corresponding side of the cycloid sundial polar plate.

10. A method for manufacturing a cycloid polar sundial according to any one of claims 1 to 9, characterized in that: The components required for the cycloid polar sundial are integrated on cardboard by die-stamping, including the following steps: Step S10: removing two rectangular sector plates marked with geographic latitude scales from the printed cardboard, and cutting the rectangular sector plates into latitude plates according to the local geographic latitude, so that the central angle of the latitude plate is equal to the local geographic latitude; Step S20: Remove the cycloid sundial polar plate, the morning time scale plate, and the afternoon time scale plate from the printed cardboard, align the 12 o'clock mark on the morning time scale plate with the local geographic longitude corresponding to the morning time geographic longitude scale, and then trim the morning time scale plate at both ends with reference to the range of the morning time cutting zone. Simultaneously, align the 12 o'clock mark on the afternoon time scale plate with the local geographic longitude corresponding to the afternoon time geographic longitude scale, and then trim the afternoon time scale plate at both ends with reference to the range of the afternoon time cutting zone. Step S30, assembling the two cut latitude plates on the lower sides of the two ends of the polar plate of the cycloid sundial; Step S40, installing the morning time scale plate in the morning time cutting area, and installing the afternoon time scale plate in the afternoon time cutting area; Step S50: Remove the cycloid sundial plate and the two right-angled triangular support plates from the printed cardboard, fold the cycloid sundial plate in half along the dotted line, and then install the two right-angled triangular support plates on both sides of the cycloid sundial plate. Step S60 , installing the cycloid sundial plate assembled in step S50 on the cycloid sundial polar plate assembled in step S40 .

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