Solar compass.

Abstract

A sundial compass (1) comprising: a mounting bracket (2) of substantially planar shape; a disk (3) rotatably mounted on the mounting bracket about an axis of rotation (X) substantially perpendicular to said mounting bracket, the disk having (on its periphery) an angular scale (31); an angular selection stylus (4) rotatably mounted about said axis of rotation (X). The stylus has a slot (41) extending through the stylus (4) along the direction of the axis of rotation and radially to the axis of rotation, between a proximal end of the stylus located on the side of the axis of rotation and a distal end of the stylus with respect to the axis of rotation. Figure for publication: Figure 1

Description

Title of the invention: Solar compass. Scope of the invention

[0001] The present invention relates to a solar compass.

[0002] The solar compass, or solar compass, is a navigation instrument that allows one to find north from the shadow of a gnomon projected by the sun. Previous art

[0003] In the field of navigation and orientation, determining angles has long been an essential task for travelers and explorers. One of the traditional methods of measuring angles is to cast a shadow using a plumb line.

[0004] This ancient technique has proven effective in estimating angles in various contexts, from ancient civilizations to industrialized countries, including developing countries.

[0005] However, this approach, despite its widespread use, has several inherent drawbacks that limit its accuracy when used to measure angles in a research project. The slightest tremors or body movements during measurement can significantly impact the accuracy of the angle estimate.

[0006] Most known sundials use a gnomon, which is an opaque piece of solid material capable of casting a shadow on a panel. The gnomon may be a long, thin, opaque stylus or an opaque sphere.

[0007] The Bagnold compass is known; it consists of a graduated disc with a gnomon in its center. It is used with a conversion table that gives the azimuth of the sun for the date and time of the observation (at the given latitude). The disc is oriented so that the shadow of the gnomon corresponds to the azimuth at the time of the observation. The 0°-180° axis then indicates the north-south axis. For the shadow to reach the edge of the disc, where the reading will be taken when the sun is very high in the sky, the gnomon must be very large.

[0008] The invention aims to overcome the disadvantages of the prior art and in particular to reduce the synchronization time in the event of a problem occurring in the synchronization.

[0009] The present invention therefore aims to provide a solar compass which does not have a gnomon and is less bulky.

[0010] To this end, according to a first aspect of the invention, a sun compass is proposed comprising: a mounting support of substantially flat shape; a disk mounted for rotation on the mounting support with respect to an axis of rotation substantially perpendicular to said mounting support, the disk having an angular graduation; an angular selection stylus mounted for rotation about said axis of rotation (X).

[0011] The stylus has a slot which extends through the stylus in the direction of the axis of rotation and radially to the axis of rotation, between a proximal end of the stylus disposed on the side of the axis of rotation and a distal end of the stylus with respect to the axis of rotation.

[0012] Preferably, the stylus has an upper face, part of which forms an acute angle with the axis of rotation.

[0013] Two retractable sights can be mounted on either side of the stylus, that is to say, respectively, at the distal end and at the proximal end.

[0014] Preferably, the stylus has a window at its distal end.

[0015] According to a second aspect of the invention, a method for determining geographic north is proposed, implementing a device according to the first aspect of the invention, comprising: a step of obtaining a uniform beam of light on the disk by moving the stylus around the axis of rotation; a step of angularly positioning the disk so that the angular graduation intersected by the beam of light corresponds to a predetermined azimuth of the sun; a step of determining geographic north by reading north on the angular graduation.

[0016] Advantageously, the predetermined azimuth of the sun is determined by a user by means of a computer application stored in the memory of a user mobile terminal equipped with geolocation means. Brief description of the figures

[0017] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for an understanding of which reference should be made to the accompanying drawings, in which: - [Fig. 1] illustrates one embodiment of a solar compass according to the invention, - [Fig.2] illustrates a disc of the solar compass shown on [Fig.1], - [Fig.3] illustrates a sighting device for the solar compass shown in [Fig.1], And - [Fig.4] illustrates an embodiment of a process according to the invention.

[0018] The embodiments described below are not in any way limiting; variants of the invention may, in particular, be considered comprising only a selection of the features described, hereinafter isolated from the other features described, if this selection of features is sufficient to confer a technical advantage or to differentiate the invention from the prior art. This selection comprises at least one feature, preferably functional without structural details, or with only a portion of the structural details if this portion alone is sufficient to confer a technical advantage or to differentiate the invention from the prior art.

[0019] An embodiment of a solar compass 1 according to an embodiment of the invention is now described with reference to [Fig. 1].

[0020] The sun compass 1 comprises a mounting bracket 2, a disc 3 and a stylus 4.

[0021] The mounting bracket 2 is preferably substantially flat in shape.

[0022] The disk 3 is mounted for rotation on the mounting support 2, about an axis of rotation X substantially perpendicular to the mounting support. The disk preferably has an angular graduation 31 on its periphery.

[0023] The stylus 4, preferably of substantially tapered or elongated shape, also called the angular selection device, is mounted to rotate about the axis of rotation X.

[0024] According to the invention, the stylus has a slot 41 which extends along the direction of the axis of rotation and radially to the axis of rotation, between a proximal end of the stylus disposed on the side of the axis of rotation and a distal end of the stylus with respect to the axis of rotation.

[0025] The slit acts as a window to let the sun's rays through and allow their diffusions on disk 3. The width of the slit is typically on the order of a few tenths of a millimeter, for example on the order of 0.5 mm.

[0026] The stylus may have an upper face of which a portion 42 forms an acute angle with the axis of rotation X. Thus, it is possible to "turn" this surface towards the sun.

[0027] As shown in [Fig. 2], the angular scale 31 may have two scales, one internal and the other external, respectively located inside and outside the same circumference. The two scales are 180° apart. This common angular scale 31 allows for a dual reading to determine, on the one hand, the angle of the cast shadow, indicated by the internal scale, and on the other hand, the azimuth of the sun, indicated by the external scale.

[0028] Disc 3 may include a compass rose 34.

[0029] The sun compass may further include a device 5 for locking the stylus 4 in rotation, and / or a device 6 for locking the disk 3 in rotation, a horizontal adjustment system 7, and / or a horizontal flatness device 8.

[0030] The rotation locking device 5 is, for example, a locking screw disposed between the stylus 4 and the rotation axis X. The locking screw could be replaced by a brake, for greater simplicity and practicality.

[0031] The rotation locking device 6 is for example a brake disposed between the disc 3 and the support 2. The brake can for example be made by means of a clamp.

[0032] The horizontal adjustment system 7 may include two horizontal adjustment screws 71, 72 mounted on the support 2.

[0033] The horizontality checking device 8 may include a bubble level, fixed on the support 2.

[0034] As particularly visible on [Fig.3], two retractable sights 42 can be mounted on either side of the stylus 4. Each of the retractable sights can have a central bar.

[0035] Furthermore, the stylus 4 may have, at its distal end, a window 43 allowing for easier reading of the angular graduation 31.

[0036] A method P for determining geographic north implementing device 1 is now described with reference to [Fig.4].

[0037] When the solar compass 1 includes the horizontal adjustment system 7, the method P includes an optional step El for adjusting the horizontality of the solar compass 1. The horizontality of the solar compass can be checked by means of the horizontality checking device 8, when provided.

[0038] The method P then includes a step E2 of obtaining a uniform light beam on the disk 3 by moving the stylus 4 around its axis of rotation X. By uniform light beam, the aim is to have the most uniform light beam possible. By uniform light beam, we mean a light beam having a rectangular shape among the shapes obtained when the stylus is moved angularly around its axis of rotation.

[0039] When the solar compass 1 includes the system 5 for locking the stylus 4 from rotation, the process P then includes an optional step E3 for locking the stylus 4 from rotation.

[0040] The method P then includes a step E4 of angularly positioning the disk 3 so that the angular graduation indicates the azimuth of the sun at the point of its intersection with the beam of light. The angular positioning of the disk 3 is achieved by rotating the disk about the axis of rotation X.

[0041] When the solar compass 1 includes the system 6 for locking the disk 3 from rotation, the process P then includes an optional step E5 for locking the disk 3 from rotation.

[0042] The process P then includes a step E6 of determining geographic north by locating on the north graduation on the angular graduation 31.

[0043] The predetermined azimuth of the sun can, for example, be determined by a user of the process by means of a computer application stored in the memory of a user mobile terminal equipped with geolocation means.

[0044] When the solar compass 1 has retractable sights 9, it is possible to point a target on the horizon using said sights.

[0045] Of course, the invention is not limited to the examples just described, and many modifications can be made to these examples without departing from the scope of the invention. Furthermore, the various features, forms, variants, and embodiments of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive.

Claims

Demands

1. A sun compass (1) comprising: a) a mounting bracket (2) of substantially planar shape; b) a disk (3) rotatably mounted on the mounting bracket about an axis of rotation (X) substantially perpendicular to said mounting bracket, the disk having an angular graduation (31); c) an angular selection stylus (4) rotatably mounted about said axis of rotation (X); characterized in that the stylus has a slot (41) extending through the stylus (4) in the direction of the axis of rotation and radially to the axis of rotation, between a proximal end of the stylus disposed on the side of the axis of rotation and a distal end of the stylus with respect to the axis of rotation.

2. Sun compass (1) according to the preceding claim, wherein two retractable sights (42) are mounted at the distal end and at the proximal end on the stylus (4).

3. Sun compass (1) according to any one of the preceding claims, wherein the stylus (4) has a window (43) at its distal end.

4. A method for determining geographic north implementing a device according to any one of the preceding claims, comprising: a) a step (E2) of obtaining a uniform beam of light on the disk (3) by moving the stylus (4) around the axis of rotation (X), b) a step (E4) of angularly positioning the disk (3) so that the angular graduation (31) intersected by the beam of light corresponds to the predetermined azimuth of the sun, c) a step (E6) of determining geographic north by reading north on the angular graduation.

5. A method according to the preceding claim, wherein the predetermined azimuth of the sun is determined by a user by means of a computer application stored in the memory of a user mobile terminal having geolocation means.

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