EP1483630B1

EP1483630B1 - Watch comprising a solar time display

Info

Publication number: EP1483630B1
Application number: EP20030702275
Authority: EP
Inventors: Eric A. Loth
Original assignee: British Masters SA
Current assignee: British Masters SA
Priority date: 2002-03-08
Filing date: 2003-03-05
Publication date: 2010-05-05
Anticipated expiration: 2023-03-05
Also published as: WO2003077043A3; AT467157T; US20050207283A1; EP1483630A2; DE60332431D1; EP1343056A1; US7372781B2; WO2003077043A2

Abstract

The invention relates to a watch comprising civil time display means (12, 16), solar time display means (13, 18) and means of correcting (24, 34, 36) said displays. According to the invention, the correction means are arranged in such a way as to allow the relative desynchronisation of the civil time display means and the solar time display means. The inventive watch also comprises means of displaying said desynchronisation (20, 22).

Description

The present invention relates to watches with a solar time display. Time management, on our planet, is today based on a reference time, called GMT and on a structure of time zones, within which the civil time is everywhere the same. Such a definition of time greatly simplifies human relationships. This time is, however, out of sync with solar time, a function of the longitude of a place, which is displayed by sundials. The object of the present invention is to provide a watch for knowing both the calendar time and the solar time, for any longitude and in any time zone.
For this purpose, the watch according to the invention comprises means for displaying the civil time, means for displaying the solar time and means for correcting the displays of civil and solar time. According to the invention, said solar time display means are arranged to perform a turn in twelve or twenty-four hours, and the correction means are arranged to allow a manual change of the relative phase shift of the display means of the display. civil time and solar time. In addition, this watch includes means for displaying this phase shift.
In this way, for the watch to actually display the solar time, it is sufficient that the display means of the calendar time indicate the time of a time zone to be taken into account, and the display means of the phase difference between the longitude of the middle of this zone and the longitude of the place considered.
It is certainly already known to display a phase shift in reference to the mean solar time. Such a solution is described in the patent US 5,184,333 It refers to a watch displaying the equation of time, that is to say the difference between the mean solar time and the true solar time. This phase shift is performed automatically by means of a mechanism making a turn in one year and driving a cam that controls the display. The information displayed is, in fact, valid only for the median position of a given time zone, everywhere else, the displayed information is erroneous, as well for the true solar time as for the mean solar time.
There are, moreover, timepieces for making the astronomical point, for example by the patent US 1'459,710 , which describes a clock displaying both solar time and sidereal time, thus making it possible to take stock both at night and during the day, insofar as the sky is uncovered.
Since the solar time is known, and the sun is visible, it is easy to determine the direction of the geographic north by means of such a watch, especially if the means of displaying the solar time include a solar time hand. taking a turn in twenty-four hours. Indeed, just aim the sun with the solar time needle. The north is then in the direction indicated by the sun's midnight hour mark on the dial.
The invention, which is defined by claim 1, proposes three embodiments.
In a first embodiment of this watch, the solar time display means comprise a solar time hand performing a turn in twelve hours and a disc performing a turn in twenty-four hours, driven in synchronism with the needle. and with an index finger indicating the north, so that the needle and the index finger are superimposed when the hand is at midnight.
In a second embodiment,

the display means of the calendar time comprise a clock hand performing a turn in twelve hours and a first fixed dial, whose upper part corresponds to the display midday and midnight,
the means for displaying the solar time comprise a needle performing a turn in twenty-four hours, a second dial, fixed, indicating twenty-four hours on a turn, whose upper part corresponds to the midnight display,
the correction means comprise a phase-shifter disposed between the display means of the civil time and the display means of the solar time and to phase shift the solar time hand with reference to the hour hand, and
said phase shifter is provided with display means for indicating the phase shift of the solar time hand relative to the civil time hand.

In a third embodiment,

the display means of the calendar time include a clock hand performing a turn in twelve hours and a first fixed dial, whose upper part corresponds to the display midday and midnight,
the means for displaying the solar time comprise a needle performing a turn in twenty-four hours and a second dial, mobile in rotation, indicating twenty-four hours on a turn, whose upper part corresponds to the midnight display,
the correction means are arranged to allow rotation of the second dial with reference to the first dial, so as to phase out their scales, and
the first and second dial has one index and the other a scale indicating a difference in longitude, allowing adjustment of the phase shift.

In the last two embodiments, it is advantageous for the second dial to bear a mark indicating the north, arranged so that the needle and the mark are superimposed when the hand indicates midnight.
In order to facilitate the aiming of the sun, the needle comprises a sighting member to enable its orientation towards the sun, comprising a body attached to a mobile of the watch, an index extending above the body, and a target , integral with the body and on which the shadow of the index, generated by the sun, can be projected.
During the year, there is a phase difference between the mean solar time and the true solar time, known as the equation of time. The difference between the mean solar time and the true solar time is between + 15 and -15 minutes of time approximately. Such a difference has a significant influence when one wants to define precisely the direction of the north. Also, it is advantageous that the watch further comprises means for correcting the equation of time.
In order to be able to control this information, especially in order to adjust the watch if it stops, it is advantageous that the correction means of the equation of time include means for displaying the position of the earth on the ecliptic.
Other advantages and features of the invention will emerge from the description which follows, given with reference to the appended drawing, in which:

the figure 1 represents a watch allowing the display of solar time and geographical north,
the figure 2 illustrates, seen from the side, a part of the watch of the figure 1 ,
the figure 3 shows, schematically, a mechanism allowing this function, and
the figure 4 relates to a second embodiment of a watch for displaying solar time and geographic north.

The figure 1 represents a watch according to a first embodiment of the invention. It comprises a box 10 in which is housed a movement which will be partially described with reference to the figure 3 and which drives display means. The movement carries a first dial 12, central and provided with a twelve hour scale, and a second dial 13, annular, coplanar and concentric to the dial 12, and carrying a ladder twenty-four hours. It animates minute hands 14, civilian time 16 taking a turn in twelve hours, solar time making a turn in twenty-four hours.
It comprises, in addition, a longitude needle 20 disposed at the front of a third dial 22, movable and located above the dials 12 and 13. A needle 23 ensures the display of the position of the Earth on the ecliptic, a turn of the needle 23 corresponding substantially a tropical year.
A time setting ring 24 is disposed on the side of the box 10, to allow the correction of the information displayed by the watch, as will be explained later, and the winding of a mainspring if it s is a mechanical watch.
The needle 18 has visible on the Figures 1 and 2 , a body 18a, a folded tip 18b and a sighting pellet 18c, intended to facilitate the orientation of the piece to determine the direction of the north. Targeting is done by aligning the shadow of the tip 18b in the middle portion of the pellet 18c, which thus forms a target, which advantageously comprises a light line arranged between two dark sides. When the shadow and the light line coincide, the solar time hand 18 is then oriented towards the sun.
The mechanism carrying the needles 16, 18, 20 and 23 is shown on the figure 3 . It is arranged on a watch plate 26 serving as a frame for the components of the watch, and in particular its time base and its finishing gear, these being not visible because they are arranged on the hidden face of the plate 26.
The finishing gear train comprises, in a conventional manner, a minute wheel, carrying the needle 14 and meshing with a timer wheel, which is connected to the time-setting mechanism and to a wheel wheel 28, arranged in the center movement and intended to carry the needle 16.
A solar time wheel 30 is superimposed on the barrel wheel 28. It is arranged to carry the needle 18. An intermediate wheel 32, mounted on a phase shifter 34 connects the wheel 30 to the wheel 28, multiplying the movement of a factor 2.
The phase shifter 34 is pivotally mounted in the center of the plate, on the barrel of the wheel 30. It is provided with a toothed sector 34a, whose function will be explained later.
To ensure a correct display of the solar time compared to the civil time, two corrections must be taken into account:

The longitude of the place where the person is, and
The equation of time.

These corrections are provided by a return 36 meshing with the toothed sector 34a and pivotally mounted on a rocker 38. The return is kinematically connected to the clock setting mechanism of the watch, for example by a mobile, pivotally mounted on a rocker and not shown in the drawing to avoid overloading, connected to the time setting mechanism, which is controlled by the ring 24 when it is in one of its correction positions.
The return 36 is provided with a pivot 36a on which the needle 20 is fixed. When the ring 24 is in the position in which the correction mechanism is kinematically connected to the reference 36, its rotation rotates the reference 36, which drives the phase shifter 34 and, with it, the intermediate wheel 32. The latter cooperates with the wheels 28 and 30 as does a plane differential gear satellite.
As the wheel 28 is engaged with the work train, it can not be moved without further movement, so that it is the wheel 30 which rotates, and with it the needle 18.
Thus, by bringing the needle 20 opposite a point of the dial 22 corresponding to the difference between the longitudes of the place considered and the middle of the reference spindle, the needle 18 is out of phase with the hour hand 16 , so that it displays the solar time of the considered place.
The reference 36 cooperates with a jumper spring not shown in the drawing and adjusted so that it can not rotate under the effect of the torque generated by the wheel 28 on the wheel 32.
The correction of the equation of time is carried out by means of a wheel 40, making a turn in 365¼ days and carrying a time equation cam 42, and provided with a pivot 40a on which the needle 23 is driven .
The wheel 40 advantageously comprises 487 teeth. It is rotated by a pawl 44 performing a back and forth movement and controlled by a cam carried by a wheel connected to the work train and performing a turn in 18 hours. In the drawing, neither the cam nor the wheel are shown, their realization being obvious to the skilled person.
The cam 42 cooperates with a finger 38a that includes the latch 38. This finger 38a is held in abutment against the cam 42 by a spring 46 fixed on the plate 26. In this way, the latch 38 moves slowly, bearing against the cam 42, correcting the equation of time.
The dial 22 is fixed rigidly on the latch 38, by means that have not been represented, so that it follows the movement of this rocker. It comprises an index 22a for displaying the equation of time, with reference to a scale 13a of the dial 13.
The described watch therefore makes it possible to accurately display the solar time, insofar as the longitude of the place is known, by taking into account and displaying in a simple way the equation of time.
It also makes it possible to accurately determine the north direction. It is sufficient to orient the solar time hand 18 towards the sun, turning the watch so that the index 18b carries a shadow in the center of the pellet 18c. The north is then in the direction of the index 13b worn by the dial 13 in the position occupied by the needle 18 when it is midnight solar time.
The figure 4 represents a watch according to a second embodiment. We find the box 10 in which is housed a movement that leads to display means. The movement carries the first dial 12, provided with a twelve-hour scale, the second dial 13 and the minute hands 14, civil time hours 16 which makes a turn in twelve hours, and solar time 18 which makes a turn in twenty-four hours.
In this watch, the dial 13 is arranged so as to be able to rotate with reference to the dial 12 and to be angularly displaced by the time setting ring 24. The drive by the ring 24 can, for example, be done first. pulled position, by means of a mechanism well known to those skilled in the art.
The dial 12 carries an index 12a in the position through which the hour hand 16 passes at midnight and at noon, while the dial 13 carries a scale 13a opposite the index 12a, and an arrow 13b disposed of so that it is superimposed on the needle 18 when it is midnight solar time, indicating the north when the needle 18 is oriented towards the sun.
Alternatively, the dial 13 could be replaced by a rotating ring mounted on the box 10 around the ice. In this case, the bezel can be directly rotated, without involving the crown and the correction mechanism.
The scale 13a makes it possible to adjust the position of the dial 13 as a function of the longitude of the place under consideration, orienting it so that the value lying opposite the index 12a is equal to the offset of longitude between the place considered and the middle of the time zone.
This watch only takes into account the offset due to the longitude. It is also possible to complete it, with a correction of the equation of time, by a mechanism similar to that described with reference to the figure 3 . In this case, however, the wheel 32 is fixed and the pinion 36 meshes with a toothing that includes the dial 13, which would then be displaced by a rotation of the ring 14, and by the movement of the rocker 38 bearing against the cam 40.
The watch represented at figure 5 corresponds to a third embodiment. It is provided with a movement arranged in a box 10 and which will be described with reference to the figure 6 . Like the two embodiments described above, this watch is equipped with the hands of minutes 14 and 16 hours of civil time, the needle 20 and the dial 22 of longitude, the needle 23 of ecliptic, and of the time setting crown 24.
In this watch, the reading of the civil time is done on an annular dial 48 provided with a twelve-hour scale, which serves as a reference to the needles 14 and 16. The display of the solar time is achieved by means of a needle 50, making a turn in twelve hours, and a central disk 52, driven in synchronism with the needle 50 and performing a turn in twenty-four hours.
The disc 52 carries an index 52a, which indicates the north when the solar time hand 50 is aimed at the sun. The needle 50 may, in addition, be provided with a sighting device as defined with reference to the Figures 1 and 2 . He was, however, not represented on the figure 5 .
The movement represented on the figure 6 is intended to equip the watch with the figure 5 . It includes the plate 26, the barrel wheel 28 intended to carry the hour hand 16, the phase shifter 34, the reference 36, the latch 38 and the wheel 40 carrying the equation cam of the time 42 and driven by the The latch 38 is also held in abutment against the cam 42 by the spring 46.
This movement comprises, in addition, a first central sun wheel 54, superimposed on the wheel 28 and of the same diameter, a second sun gear 56, coaxial with the wheels 28 and 54. A satellite 58, meshing with both the wheel 28 and the wheel 54 is pivotally mounted on the phase shifter 34, which further carries a mobile 60, which is driven by the wheel 54 and leads the wheel 56. The adjustment of the phase difference between the solar time and the civil time is made identical to what has been described with reference to the figures 1 and 3 , as well as the correction of the equation of time. The sun wheels 56 and 58 are respectively intended to carry the needle 50 and the disk 52.
Since the wheels 28 and 54 have the same diameter, and they are kinematically connected by the satellite 58, they rotate in the same direction and at the same speed as the phase shifter 34 is fixed.
The mobile 60 and the wheel 56 have numbers of teeth chosen so that the wheel 56 rotates twice as slowly as the wheel 54, that is to say that it makes a turn in twenty-four hours.
In this embodiment, the solar time display is on the twelve hour scale, which is more usual - and therefore easier to read - than the twenty-four hour scale.
The three embodiments described above make it possible to determine the direction of the north in a given place, insofar as the longitude of this place is known, by orienting the needle 18 or 50 towards the Sun. It is also possible to determine the longitude of the place by noting, at night and on a fixed surface, the direction of the North Star, which corresponds to the geographical north. The next day, the watch is oriented so that the index indicating the north coincides with the noted direction. It is then sufficient to correct the longitude indicator until the needle 18 is aimed at the Sun.
The watches thus described thus make it possible, by simple and easy to manipulate technical means, to display both civil and solar time, and to determine the direction of the geographic north or the longitude of the place considered. These watches can, of course, be the subject of many other variants, without departing from the scope of the invention. They may or may not include a correction relating to the equation of time. Mechanisms designed to ensure the phase shift between solar time and civil time, as a function of longitude and the equation of time, may, of course, have very different structures and forms. Thus, the wheel 40 could also be associated with a conventional calendar mechanism, displaying the calendar and the month, the equation cam of the time being controlled by the mobile carrying the month indicator.
The description above relates to a mechanical type watch. It is also possible to envisage solutions using a display by means other than needles, for example liquid crystal display cells. In this case, the time base will be a quartz. So that this piece can also determine the direction of the geographical north, at least the solar time will be displayed by means of a needle simulated by indexes arranged radially on the display cell.

Claims

A watch comprising civil time display means (12, 16 ; 48), solar time display means (13, 18 ; 50, 52) and means of correction (24, 34, 36) of said displays, characterized in that said solar time display means are arranged to perform one revolution in twelve or twenty-four hours, in that said means of correction are arranged in such a way as to allow a relative manual desynchronization of the civil time and solar time display means, and in that it furthermore comprises means for displaying said desynchronization (20, 22 ; 13a).
The watch as claimed in claim 1, characterized in that the solar time display means comprise a solar time hand (18) performing one revolution in twenty-four hours.
The watch as claimed in claim 1, characterized in that the solar time display means comprise a solar time hand performing one revolution in twelve hours (50) and a disk (52) performing one revolution in twenty-four hours, driven in synchronism with said hand (50) and carrying an index (52a), indicating north, which hand is disposed in such a way that the hand (50) and the index (52a) are superimposed when the hand (50) displays midnight.
The watch as claimed in claim 2, characterized in that:
- the civil time display means comprise an hour hand (16) performing one revolution in twelve hours and a first dial (12), fixed, the upper part of which corresponds to the display of midday and midnight,

- the solar time display means comprise a second dial (13), fixed, indicating twenty-four hours over one revolution, the upper part of which corresponds to the display of midnight,

- the means of correction comprise a desynchronizer (34) disposed between the civil time display means and the solar time display means and making it possible to desynchronize the solar time hand (18) with reference to the hour hand (16), and

- said desynchronizer (34) is furnished with display means (20, 22), to indicate the desynchronization exhibited by the solar time hand (18) with respect to the civil time hand (16).
The watch as claimed in claim 2, characterized in that:
- the civil time display means comprise an hour hand (16) performing one revolution in twelve hours and a first dial (12), fixed, the upper part of which corresponds to the display of midday and midnight,

- the solar time display means comprise a second dial (13), mobile in rotation, indicating twenty-four hours over one revolution, the upper part of which corresponds to the display of midnight,

- the means of correction (24) are arranged to allow the rotation of the second dial (13) with reference to the first dial, in such a way as to desynchronize their scales, and

- the first and the second dial comprise the one an index (12a) and the other a scale (13a) to allow the adjustment of the desynchronization.
The watch as claimed in one of claims 4 and 5, characterized in that the second dial (13) carries an index (13b), disposed in such a way that it is superimposed on said hand (18) when the latter displays midnight, so that said index (13b) shows geographical north when said hand (18) is aimed at the sun.
The watch as claimed in one of claims 2 to 6, characterized in that the solar time hand (18, 50) comprises an aiming member to allow its orientation toward the sun, comprising a body (18a) fixed to a runner of the watch, an index (18b) lying above the body (18a), and a target (18c), integral with the body (18a) and onto which the shadow of the index (18b) can be projected.
The watch as claimed in one of claims 1 to 7, characterized in that it comprises, furthermore, means of correction (38, 40, 42) of the equation of time.
The watch as claimed in claim 8, characterized in that the means of correction of the equation of time (38, 40, 42) comprise means of display (23) of the position of the earth on the ecliptic.