WO1989000720A1

WO1989000720A1 - Adjustable cylindrical equatorial sun dial with wire style having a reference mark for following the variations in the sun's declination

Info

Publication number: WO1989000720A1
Application number: PCT/FR1988/000344
Authority: WO
Inventors: Jean Raffegeau
Original assignee: Jean Raffegeau
Priority date: 1987-07-16
Filing date: 1988-06-29
Publication date: 1989-01-26
Also published as: FR2618232A1; EP0328572A1; FR2618232B1

Abstract

A device on a cylindrical equatorial sun dial which can be oriented horizontally and vertically makes it possible: 1) to determine standard time to the nearest minute using a style in the form of a tensioned wire (1) which casts a thin shadow, 2) to determine the months and decades of the year (7) from the vertical displacement on the dial (of sufficient width) of a point shadow formed by a relief reference point (3) located on the wire directly below the equinox, 3) to make an adjustment to correct deviations due to the equation of time. This is done by guided lateral sliding of the cadran along the ''8'' representing the equation of time located on a fixed part (12). The position of the point shadow cast by the reference point indicates the decade of the year, from which the level of the ''8'' and hence the deviation to be compensated can be derived, 4) to obtain a reading in all seasons, including at the equinox, of the time from sunrise to sunset. This is made possible by the shape of the dial, the upper part of which is always horizontal and passes through the plane of the reference point (3), and by the constant orientation toward the local noon. A sheet on which the hour lines are marked is glued to the dial, allowance being made for the difference in order to obtain standard time.

Description

ADJUSTABLE DEVICE OF A CYLINDRICAL EQUATORIAL SOLAR DIAL WITH A FILIFORM STYLE COMPRISING AN INDICATOR FOR TRACKING THE VARIATIONS IN THE DECLINATION OF THE SUN.

By design and settings, it can be used all over the globe, from the equator to the poles, giving the legal time for each country.

In the known devices of equatorial cylindrical sundials, no means is provided to take account of variations in the equation of time, significant variations reaching almost thirty minutes. The evolution of the equation of time - resulting in an advance or a delay of the hour compared to the average hour-is related to the variations of the angle of declination of the sun during the year. My invention consists of a device allowing the knowledge of these variations.

To illustrate the device, 4 boards with the following figures are attached: The entire device in perspective: Figure n ° 1, Only the dial-frame wire holder, in profile: Figure n ° 2, in plan: Figure nº3, front: Figure n ° 4. Variations in the profile of the dial and its orientation according to latitudes: Figure nº5. Only the part of the dial containing the adjustment devices according to the time equation (with 2 different means): Figure n ° 6. These Figures are given by way of non-limiting example of one of the embodiments of the object of the invention.

DESCRIPTION OF THE STYLE DOOR-FRAME ASSEMBLY: The Style consists of a wire (1) stretched between the 2 ends of the branches of the frame (2) having the shape of a 3-sided rectangle. its middle: a landmark which can be a small ball or any other relief (3). on the part of the frame with 3 sides corresponding to the length, which is parallel to the Wire-Style, in the middle is fixed a cylindrical cradle (4) which constitutes the support of the movable dial (5). This dial, which can slide on its cradle, is constituted by a very rigid cylindrical band having for center the Fil-Style.The width of this band is given by the amplitude of the variation of the angle of the declination of the sun on both sides of l equinox during the year. Indeed, the shadow of the Marker (3) is projected onto the dial-dial in the middle at the eqύinox, below at an angle of 23 ° 37 at the summer solstice, and at the top, at the same angle, at the winter solstice. The total angle is: 23 ° 37 X 2 = 46 ° 74.This makes it possible to know the minimum width of the dial strip, i.e. after calculation, the radius of the cylinder multiplied by a coefficient of 0.86. In Length, The cylindrical screen strip will form a complete circle at the poles, being horizontal (and Style vertical). At the equator it will form a semicircle, in a vertical position, the Style being horizontal. Going from the equator towards the poles, the front edge of this semicircle is always located in a horizontal plane including the Mark (3) fixed in the middle of the wire-style (plate n ° 2, right figure.) A correct inclination of this front edge according to the degree of latitude allows the reception of the solar ray from dawn until dusk. However, the same dial profile can be used for a 10 ° latitude slice. The width of the frame strip makes it possible to know the length of the part of the frame (2) in the middle of which it is fixed. 'other of the strip the di- On both sides of the strip the dimension of the part must correspond to the maximum declination angle of the sun is 23 ° 37 rounded to 25 ° from the end of the branch supporting the Style, each side each branch must be long enough for the Fil- Style (1) be placed exactly; in the center of the cylinder formed by the movable dial (5). The Dial is graduated vertically for the hours - and by 5 minutes - by lines with regular spacing, the difference between each hour corresponding to an angle of 15º compared to the location of the Style (6). It is also graduated horizontally by lines corresponding to the 1st, 10 and 20 of each month (7) .This horizontal graduation is permitted by the existence of the Mark (3) whose shadow cast on the dial varies vertically according to the declination of the sun during the year. (see plate n ° 4). The existence of these horizontal lines indicating the decades of the year makes it possible to know the advance or the delay of the sun compared to the average hour, according to the equation of time. The shadow of the Marker (3) runs vertically through the dial (2), from bottom to top from June 14 to December 25, and vice versa. This route does not follow a simple vertical line, it deviates from side to side. other one of the average vertical of a constantly variable quantity. The drawing of this traverses resembles an "8" (which has nothing symmetrical) -see the figure on the left of the board ADJUSTMENT OF THE DEVICE. The vertical inclination and the horizontal orientation of the Frame-Dial-Style assembly can be ensured by various means. A complete device is described in perspective on Plate 4. The vertical inclination for adaptation to the latitude, variable over 90 ° is carried out by sliding the Frame (2), made in angles, on the vertical and horizontal branches of the Support (8) made in slightly narrower angles. by the Button-screw (9). The Horizontal Orientation, for adaptation to the longitude is done by rotation of the support (8) on the wall fixing piece (10) - which also serves to correct the difference existing between the actual orientation of the wall and the due south orientation that the dial must have. The positioning of the device, during its installation, must be done with perfect accuracy. If it is placed on a surface close to the horizontal, perfect horizontality will be obtained by the operation of the 2 button-screws (l3) located at the 2 ends of a part fixed perpandiculately to the front of the support. If the device is fixed to a wall, the fixing piece (10) must be absolutely vertical; in both cases a control by precise water level will be necessary. For a sundial of high precision (of the order of a minute) the settings must be extremely precise, therefore they are difficult to achieve by using numbered dials fixed on the device. On the other hand we will see later that the he existence of the Benchmark (3) will constitute a capital aid for the 2 adjustments. SETTINGS TO DO ONCE FOR ALL. It is still advisable to start by making adjustments using the graduations written on the device. For the vertical inclination, on one or the other of the branches of the support (14). For horizontal pivoting, on the semicircle dial (11) located at the bottom of the vertical wall attachment piece. The degree of latitude and longitude of the place will be given by an IGN type map.

IMPROVED ADJUSTMENT. -In Latitude: It is necessary to make the shadow cast by the Landmark coincide with the line of the dial corresponding to the day. It will be easier on the 1st, 10th and 20th of each month, and more precise in the middle months of the band-dial where the lines are more apart. In Longitude: The Dial must be oriented due south, the shadow of the Style at noon local time being just at the bottom of the dial. We can deduct this midday local time from the midday legal hour (indicated by a watch), taking into account the difference in longitude of the place compared to the meridian chosen by the Country for its legal time. We transform these degrees into minutes at the rate of 4 minutes for a degree. The vertical line corresponding to the Legal Midi (in France, 13 or 14 hours) will be located on one side or the other of the central line of the raidi-local, with the corresponding difference in minutes. (1 minute = 1/720 of the 1/2 circumference of the dial.). To do the same operation of control and adjustment by the effective placement of the shadow of the Style at the correct time indicated by a watch, which we did with latitude with the day, we must take into account the 'Equation of the time and of the deviation from the average time which results from it for the day of the setting. For this we use the Segment for the equation of time (12). It is constituted by ^a dial of a suf ficient segment width to contain the "8" previously explained, about 40 minutes, made of a plastic tranparente.Ce segment slightly larger than the movable dial plate material may be attached to the Cradle (4) and immobilized by the screw button (13) .It is designed to allow the mobile dial to slide freely, while being in front of it. First, place and immobilize the Segment so that its vertical line coincides with the center of the cadra When the watch indicates the (legal) time corresponding to local noon-hour (which was calculated previously), the shadow of the Mark (3) must be on the line of "8" If this is not the case, perfect the adjustment by rotating the frame-dial-style assembly. From this final adjustment, we are sure that the center of the dial is well oriented due south. The difference in minutes between noon-local and noon-legal being known, we will know the location of the average legal-noon compared to the local-noon located in the center of the dial. We will then have to move the Segment for the equation of time (12) so that the central vertical line of this segment coincides with this location and immobilize it one last time using the screw button (13) All the settings for adaptation to the location are now complete, and the dial band (5) not yet slid, its 2 sides have remained symmetrical, which is essential for the reception of the first and last rays of the sun. From now on the only adjustment will be that coming from the variations of the equation of time.

SETTINGS FOLLOWING THE EQUATION OF TIME. To keep the symmetrical position of the dial, inscriptions cannot be made directly on this dial. hours (and 5 minutes), and horizontal decades are produced on an independent strip of fairly flexible, dimensionally stable, white material, over a length greater than the dial, if possible self-adhesive. This strip will be stuck on the banà-cadr.an so that its midday line (1 and 2 pm in France) coincides with the central vertical line of the Segment for the equation of time already fixed at the Cradle. Possibly it is also possible to fix this segment opposite any time as long as it is visible at the winter solstice. The parts of the glued strip protruding on each side of the movable dial (5) will be cut. Thereafter, the movable dial hitherto remaining well in the center will slide to follow the variations of the equation of time. This adjustment can be made, at any time of the day, by sliding the mobile dial so that the line of the "8" (of the season) of the Segment for the equation of time coincides with the intersection of the reference time line on the dial and the horizontal line corresponding to the day of the year and which is defined by the shadow of the Marker (3). On board n ° 4, on the right, is the Segment for the equation of time on the dial. On the left is another adjustment method allowing the Segment to be replaced by a simple wire. In this case, the dial itself must have a trace of "8" on the reference time, but reversed laterally. The adjustment then consists of make coincide with the wire the intersection of the line of "8" with the horizontal line of the day and defined by the shadow of the Marker.

Claims

CLAIMS 1 °) Device, on a cylindrical equatorial sundial orientable horizontally and vertically, for knowing the legal hours with a precision of one minute, from sunrise to sunset on all points of the globe, characterized in that it has in the center of the cylinder a Style composed of a simple wire (1) stretched between the two branches of a frame (2). In the middle of this wire is fixed a mark (3) in relief. dial (5) by the wire is thin enough to distinguish a minute. The shade formed by the marker varies vertically each day according to the declination of the sun, which makes it possible to know the dates. The height of the dial (3) must be sufficient to contain the variation of the declination of the sun, the top of the declination angle being the Mark (3). 2 °) Device according to claim 1, characterized in that the dial, although having to indicate the legal time, is howeverforienté full south of the place where it is placed. The printed band comprising the lines of the hours and months, independent of the dial is glued on it at the appropriate place to give the legal time. 3 °) Device according to claim No. 1, characterized in that the cylinder-dial (5) is cut on each side along a line located in the horizontal plane passing through the marker (3), this being possible that having complied with claim No. 2. This device allows the reception of the sun's rays from sunrise to sunset, and to have no intuition at the equinoxes. 4 °) Device according to claim 1, characterized by the possibility of rotation of the cylindrical dial (5), which rests on the fixed cradle (4), in order to be able to continuously adjust its position according to the variations of the equation of time.

3 °) Device according to claim 4, characterized in that it comprises a transparent dial segment (12) intended to guide the rotation of the movable dial (5). The line describing the evolution of the equation of time, in the form of "8" on either side of a vertical line representing the average hour, is written there. This segment placed in front of and. flush with the dial, however, is fixed on the fixed cradle (4) taking into account, for a given hour close to the center of the cadra, the difference in longitude with the reference meridian, and the difference according to the equation of time corresponding to the day of fixation. For this it is necessary that the intersection of the horizontal line contains nant the Mark (3) and the branch of the "8" corresponding to the season is put in coincidence with the vertical line of the time of the moment and which must be the one chosen to then serve as the reference time 6 °) Additional device realizing claim nº5 by a different means, the Segment (12) is replaced by a wire (15) corresponding to the average hour, passing in front of the dial but fixed to the Cradle (4). The "8" is drawn directly on the dial ,. around the selected time, but laterally reversed. The setting consists in making the intersection of the branch of "8" and the horizontal line containing the Mark (3) coincide with the vertical line of the chosen hour as reference, represented by the Wire.

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