FR2635181A1 - Solar navigation device - Google Patents

Abstract

The invention relates to a device for navigation by the shadow cast by an index on an hour dial (clock face). It consists of a plate 1 etched with a circular protractor 2 on which are superposed a small plate 4 carrying an index 5 and an hour dial (clock face) 3 which both pivot on a pin 7. Use: by positioning the index 5 vertically facing the hour marking on the dial 3 which corresponds to half the number of divisions between the universal time and noon, the figure XII of the dial 3 coinciding with the 180 DEG of the protractor 2, pointing the apparatus horizontally towards the sun, with the 180 DEG side towards the sun, executing a translational movement until the shadow cast by the index 5 passes through the pin 7. The line 180-360 DEG of the protractor 2 then coincides with the south-north line (south side at 180 DEG ).

Description

DESCRIPTION
The present invention relates to a solar orientation device making it possible to determine with sufficient precision, the cardinal points,
to orient themselves and to determine angels and directions of walk.

 The orientation and determination of angles and directions of walking are traditionally obtained by instruments of the magnetic type, such as compasses, gyroscopic or by a watch.

 Magnetic Instruments involve risks of error due mainly to declination phenomena, variable depending on the place, time or year of observation and difficult for the user to assess in the Unknown region, to magnetic influences from the surrounding environment, such that: electric currents, magnetic storms or proximity: of ferrous masses, magnetic minerals, permanent magnets, electromagnets etc ...

 Gyroscopic instruments have the disadvantage of being large, difficult to use.

 The watches can indicate the SOUTH-NORTH axis, provided however that the hands are sufficiently dimensioned, and that the divisions of the dial are readable; which is not the case with modern watches having a display panel with luminous crystals.

 The device according to the invention overcomes these drawbacks and peddles in its preferred embodiment: a rigid plate (l) on which is engraved a circular protractor (2) crosses in its center.by -a hollow axis (7) on which pivot freely: a clockwise graduation dial (3) and a plate (4) supporting a perpendicular folding arm (5) which can be brought opposite any of the graduations of the protractor (2) or dial (3 ) clockwise, by rotation around the axis (7). An ovible needle (8) can be housed in the tubular axis (7).

The invention is set out below in more detail with the aid of the drawings in which
Figure 1 shows the device according to the invention in elevation.

 Figure 2 shows the device according to the invention seen from above.

 FIG. 3 represents the device according to the invention in section along M.

 Figure 4 shows in detail the plate and its folding arm.

 Figure 5 shows the wafer in section.

 Figure 6 shows the elevatlon device in use for angle readings and determination of the time in UT (Universal Time).

 The solar orientation device of figure 1 comprises a rigid transparent rectangular plate, on which is engraved a circular protractor graduated in degrees (or grades) whose diameter 1800 - 360 "(or 200 - 400 gr) merges with the large center of the stage A graduated, transparent, rigid hour dial with a diameter smaller than that of the protractor pivots freely and flat around a hollow axis coming from the center of the protractor. diameter in termediaire between these two pieces, a transparent plate carries on its edge an index or folding arm, arm support plate and hourly dial rotate freely and individually on the same hollow axis center on the middle of the protractor.

 To find the SOUTH NORTH line from where it is located, the observer must know the time in UNIVERSAL TIME (or GMT) of the observation point, and have sufficient solar lighting to cast the shadow of 'an object.

 Raise the arm of the wafer perpendicular to the instrument, bring it in front of the graduation of the sundial giving the UTC time of the moment. Rotate the plate and hourly dial assembly so that the bisector of the angle formed by the hourly graduation (in TU) retained and the number XII of this same dial comes to merge with the line 1800.3600 (or 200-400 gr ) of the rapporteur. Orient the instrument horizontally, the number 1800 (or 200 gr) towards the sun until the projected shadow of the arm passes through the hollow axis of the device. The large median of the plate then gives the line SOUTH-NORTH, the SOUTH being located on the 180 tou 200 gr side of the protractor.

 According to another use, angles can be carried out in the following way: the apparatus being suitably oriented horizontally, inserting a needle in the hollow axis, aiming therewith for the objective whose angle is to be known with respect to the NORTH, insert the folding arm erected perpendicularly in alignment. Read the value of the angle sought next to the position of the arm on the protractor.

 According to a third use: determining an angle and a direction of travel. Bring the folding arm to the vertical position on the protractor and opposite the scale corresponding to the desired angle. Attach a needle in the hollow axis orient the device properly horizontally and aim in nature by alignment: needle - folding arm, a remarkable detail. The desired direction is located (this remarkable detail.

 According to a fourth use: find the time in Universal Time subject to being on the SOUTH NORTH line obtained by a different means (map,. Engraved I6N terminal etc ...). Orient the device properly horizontally. Place the number VI on the hourly dial opposite the 1,800 or 200 g of the protractor, insert a needle in the hollow axis, read the hour on the hourly dial indicated by the projected shadow of the hand. By multiplying by 2 this hour, we obtain the time in Universal Time of the place where the observation is made.

 The device according to the invention is particularly intended for the orientation of people traveling in the great outdoors, possibly to take readings of walking or direction angles, and to obtain the time in Universal Time.

Claims (5)

 1. Solar orientation device characterized in that it comprises superimposed on each other and flat  a rectangular plate (1) on which is engraved a graduated circular protractor (2) around the axis of which pivot freely and independently  a circular plate (4), of a diameter smaller than that of the protractor, on the edge of which is fixed a perpendicular index or vertical arm (5),  a circular time dial (3) with a diameter smaller than that of the plate (4).  2. Device according to claim 1, characterized in that the pivot axis (7) assembles the three above parts together, leaving them free to rotate independently of one another around it.  3. Device according to claims 1 or 2, characterized in that the index or arm (5) is foldable towards the center of the device by articulation on an axis (6) of the support (9).  4. Device according to claims 1 - 2 3 characterized in that the stroke of the index finger or arm (5) is stopped outwards by a projection (10) of the support (9).  5. Device according to claims 1 - 2 - 3, 4, characterized in that the pivot axis (7) is tubular so as to receive a removable needle (8) for the use of the device in angle measurements and in gnomon .