FR2674039A1 - Device indicating the times of tides - Google Patents

Abstract

The device indicating the times of tides on the basis of a clockwork movement comprises: - a first indicator turning at a rate of one revolution in 59 days in front of a graduation calibrated as a function of the periods of Spring tides, neap tides and intermediate periods, - a second indicator (37) turning at a rate of one revolution in 12 hours 25 minutes and 14 seconds in front of a circular graphic assembly (35, 36) representing the time remaining before a high tide or a low tide as a function of the period of Spring tides, neap tides and intermediate periods.

Description

INDICATOR DEVICE
THE SCHEDULE OF NAREES
The present invention relates to a device indicating the time of the next rising or falling tide and / or the time remaining before such an event, and this at any time of the year and regardless of where the observer is locates. Such a device finds all its utility for navigators wishing to calculate the optimum moment to enter a port, that is to say at high tide; or for people wishing to collect shells at low tide in the intercotidal zone.

 Usually, people who need to know the time of a next tide consult a calendar officially published each year by the Maritime Administration.

However, this calendar is in the form of a thick, bulky book that is not easy to handle.

 Given that the tide cycle, which mainly follows the lunar cycle, has an average duration of 12 hours 25 minutes and 14 seconds, indicators have already been designed based on a clockwork movement turning on a near rhythm to directly indicate the state of the tide, or the time to run until the next high or low tide. Such indicating devices are for example described in the presentations FR 2 629 607, FR 2 646 724, FR 2 479 496 and FR 2 645 977.

 But this tidal cycle is actually disrupted by other factors such as the moon phases, the equinoxes, the local relief and the cotidal wave. The combination of these influences can lead to errors of appreciation of more or less 1 hour compared to the lunar cycle taken as reference, and in the worst case until a delay of 8 hours depending on the places of observation, whereas the average period between a high tide and a low tide is only around 6 hours. Examination of the aforementioned devices shows that they are either too simple and therefore inaccurate, or too complicated by the multiple corrections making them difficult to understand at the time of reading, and therefore also unusable.

 The object of the present invention is a device indicating the timetable or the time remaining before the tides which, once correctly set, gives indications with greatly increased precision, and this in a simpler and therefore more understandable manner.

These goals are achieved thanks to a device indicating the tide schedule comprising a watch movement to rotate an indicator in front of a graduated dial, because it more particularly comprises - a first indicator rotating at the rate of a revolution in 59 days before a graduation calibrated according to the periods of
Vives Eaux, Mortes Eaux and intermediate periods, - a second indicator rotating at the rate of a revolution in 12 hours 25 minutes and 14 seconds in front of a circular graphic assembly representing the time remaining before a Full Sea or a
Low Sea according to the period of Vives Eaux, Mortes Eaux and intermediate period.

 Thanks to this device, an important correction whose value varies over time can be carried out very simply.

In a first preferred embodiment, the second indicator is a needle and the corresponding graphic assembly comprises two graphic subsets. The first sub-assembly occupies the external right part of the dial and is formed by the intersection of a series of concentric arcs of a circle with an apex angle between 180 and 200 starting jointly from an oriented radius. towards the top of the dial, and of a series of oblique lines oriented in the direction of movement of the needle starting from the internal semicircle corresponding to the periods of
Dead Waters towards the external circle corresponding to the White Water periods. This external semicircle is completed with a regular graduation in time remaining before the next Low Seas.

The oblique lines represent the corrections in decreasing time remaining for the other periods. The second subset, similar to the first, occupies the internal left part of the dial with the radii of the arcs-of-circle lower than those of the first and ending jointly on the radius of the departure, the external arc-of-circle corresponding to the Whitewater periods being completed by a regular graduation in time remaining before the next
Deep sea.

 In this embodiment, the corrected time is very easily read by following the needle up to the arc-circle corresponding to the period of Vives Eaux, Mortes Eaux or intermediate of the moment, then following the oblique line of correction up to the hourly graduation.

 Advantageously then, the regular graduation in time of the external arc of the first graphic sub-group is carried out on a movable crown making it possible to modify the hourly rise-fall ratio of the tide as a function of the desired location such as indicated by marks.

According to another preferred embodiment of the invention, the graphic assembly comprises two concentric hourly graduations denominated in the same direction, and the indicator is in the form of two opposite circular sectors rotating at their common apex, the radius of the first sector corresponding to the radius of the internal scale for the time remaining before the Bass
Sea, the radius of the second sector corresponding to the radius of the external graduation for the time remaining before Full Sea, each edge in a semicircle carrying a series of marks corresponding respectively to the periods of White Water to Dead Water.

In this embodiment, the conventional needle is replaced by a circular sector whose side in an arc opposite the top carries a series of marks corresponding to the different periods between Vives Eaux and Mortes
Waters. Two indicators, one corresponding to the Full Seas the other to the Low Seas, being opposite, it is possible at any time, in this variant, to simultaneously read the remanent time until the
Full Sea and the following Low Sea.

 If desired, the two circular indicator sectors are produced on a rotating eccentric disc which can then bear two distinct mentions "rising" and "descending". In addition, the eccentric disc tends to rotate, b hiding the portion of the internal graduation unnecessary at a given time.

Useful then, the external hourly graduation can be carried out on a mobile crown making it possible to modify the hourly rise-fall ratio of the tide according to the desired location as indicated by markers.

 Advantageously, the device according to the invention is associated in a wristwatch with a second watch movement rotating on a solar rhythm, the upper case of which is folded over the lower case of the device by rotation around a hinge. Useful then, the back of the upper case of the second movement has an engraved table indicating the correction depending on the location due to the cotidal wave.

The invention will be better understood from the study of embodiments taken by way of nonlimiting examples and described by the following figures.
FIGS. 1a and 1b are perspective views of a wristwatch respectively with its upper case in the closed then open position to show the device according to the invention housed in the lower case,
FIG. 2 illustrates the detail of the graduation in terms of Vivid Water / Dead Water of the lunar phase indicator,
FIG. 3 illustrates a first embodiment of the device according to the invention,
FIG. 4 illustrates a second embodiment of the device according to the invention,
FIG. 5 illustrates an initial calibration process as a function of the equinoxes, and
- Figure 6 illustrates a table indicating, by French ports, the category of relief and the time corrections due to the cotidal wave.

 FIG. 1 illustrates the device according to the invention produced in a wristwatch version to be worn permanently on the handle, it being understood that this device can also be produced in a pendulum version with several dials side by side optionally mounted in a cardan box for installation in a boat. The wristwatch 10 comprises a lower case 30 to which the bracelet is attached and an upper case 20 which folds over the lower case 30 by rotation around a hinge 15. This upper case 20 is held in position for example by a hook, not shown, located on the opposite side of the hinge 15.

 The upper case 20 contains a conventional watch, that is to say a solar clock movement indicating the time, this movement being supplemented by a lunar phase indicator 25. With reference to FIG. 2, this lunar phase indicator 25 comprises a disc on which two opposite moons are represented, this rotating disc b due to a revolution in 59 days behind a window whose lower edges have two adjacent arcs. As can easily be understood, a new moon corresponds to the indicator appearing on the left side of the window, a full moon corresponds to the indicator located in the center of the window and a last quarter corresponds to the indicator partially hidden by the right part of the window.

According to the invention, the upper part of this window is completed with a graduation 27 calibrated according to the
Whitewater and Deadwater. Vives Eaux means a period during which the difference in water level between low tide and high tide is at its maximum, and Mortes Eaux means a period during which this difference in water level is at its minimum. For example, in the port of Le Havre in January, the sea level is at 7.75 my high tide for 1.80 my low tide during the Vives period
Waters and only at a level of 6.40 m at high tide for 3.75 mb low tide in Mortes Eaux. As indicated by the graduation 27 of figure 2, the periods of White Water correspond to periods of full moon and new moon while the periods of
Dead waters correspond to the rising and falling quarters. In fact, the evolution of correction in the Dead Water to Live cycle
Water is faster than in the Whitewater to Dead cycle
Waters. For better accuracy, the period between a Whitewater and a Deadwater is itself divided into five sub-periods corresponding, on the graduation, to different color markers.

With reference to FIGS. 1 and 3, the tide indicator device comprises a second timepiece movement turning a hand 37, here clockwise, at a rate of rotation in 12 hours, 25 minutes and 14 seconds which is associated with a second second hand 39 indicating the seconds, second hand present here only to confirm the proper functioning of the second watch movement. This needle 37 moves in front of a graphic assembly allowing it to successively indicate the time remaining until a low tide or Low Sea "BM" then the time remaining until a high tide or
Full Sea "PM".

The graphic assembly includes a first subset 35 on the external right part. This graphic subset is firstly made up of a series of arcs 42, in this case five, one for each period of Vives Eaux, Mortes
Waters or intermediate as indicated by the graduation appearing on the window of the lunar phases described previously, these arcs-circle starting from the same radius 41 and whose angles in the center are between approximately 1800 for the arc-de -internal circle corresponding to the Dead Water and around 250 for the external arc corresponding to the White Water. The external arc is located near an hourly graduation of a maximum of 8 hours indicating the time remaining until the Low Sea "BM". The graphic subset 35 also includes a series of lines obliques 44 oriented in the direction of rotation of the needle 37 as considered from the internal arc to the external arc. These lines 44 materialize a correction to be made in "reduction of time" remaining before the Low Seas to be applied during the Dead Water period compared to the very regular period of
Living waters. As can be seen, these lines 44 are by no means rectilinear but in the form of an S showing the evolution of the correction during the intermediate periods. In other words, the Low Sea time during the White Water period turns out to be regular compared to the 12 hour and 25 minute cycle, while the Low Sea takes place earlier in the Dead Water period.

 Similarly, the dial of this second movement carries a second graphic sub-assembly 36 in the internal left part. As before, we recognize a series of circular arcs 43 which, in this case, lead jointly to the reference rays 41 and whose angle at the center is approximately 2500 for the innermost arc also corresponding to a Dead Water period and around 1900 for the external arc also corresponding here to a White Water period. We also find the series of correction lines 45 which is no longer in the form of an S but a simple curve. The external arc is also graduated regularly in the hours remaining before high tide "PM".

 As can be seen in FIG. 3, the hourly graduation 46 is in fact carried out on a movable crown which can thus be rotated to match the mark "BM" opposite marks 48 in the form of letter A, B, C and D. As can be understood, it is possible to modify, by rotation of this crown, the hourly ratio between a falling sea and a rising sea. For example, for a place referenced D, the period of descent of the water is approximately 7 1/2 hours while the period of rise of the water is reduced to only 4 1/2 hours, which is to be compared to an average approximately 6 hours 13 minutes.

 In FIG. 4 is illustrated a second variant of the device of the invention in which the graphic assembly essentially consists of two concentric circular graduations of 12 hours and 20 minutes each, one internal 56 for determining the time remaining until a low tide or "BM", the other external 57 for determining the time remaining before a high tide "PM". As previously, the external graduation 57 is in fact carried out on a movable crown making it possible to modify the hourly ratio between a rising or falling phase of the sea according to the places referenced by the indices 55 A, B, C and D.

 The indicator 58 is presented here in the form of a disc eccentric with respect to its center of rotation coincident with that of the graduations. This disc 58 is offset so that the minimum distance between the center of rotation and its periphery corresponds to the radius of the internal graduation and the maximum distance between its center of rotation and its periphery corresponds to the radius of the external graduation 57. On the portion of the periphery located closest to the center of rotation then represents a series of indexes 52 for reading the time remaining before the next Low Sea depending on whether one is in the period of high water or dead water. Similarly, a second series of indexes 52 for reading the time remaining before the next Full Sea is plotted on the portion of the periphery located furthest from the center of rotation, and therefore opposite the first.

 In other words, and as can be seen in this figure 4, the indicator of this embodiment can be considered as formed by two opposite circular sectors, a small 53 and a larger 54, delimited by a first straight line joining the two indexes marked "VE" and a second straight line joining the two indexes marked "ME". The advantage of this disc is to scroll two words "rising" and "descending" indicating, in an obvious way, in which phase of movement of the sea we are.

 Before using the device, like any watch movement, it should be set beforehand. The adjustment of the solar and lunar movement contained in the upper housing 20 is done in a known manner.

 It is then necessary to calibrate the movement of the tide on the annual average. The tide cycle being 12 hours 25 minutes 14 seconds compared to a lunar cycle of 59 days, the oblique lines of Figure 5 illustrate the temporal drift of a reference event, such as a Full Sea in Full Moon, as the months go by. However, if we consult a tide calendar and report on this graph the exact hours of the reference event for the year 1990, we find a peak late in March and a second peak early in the month of September corresponding to the phenomenon of the equinoxes. This graph then makes it possible to determine an average oblique line, marked by a double line in FIG. 5, for this reference event. We can then either wait for this reference event for a given month, and at this precise moment, set the indicator in front of the corresponding index or, by calculation, determine the time remaining before the next event and position the indicator accordingly. This graph being established according to the year and also according to the port chosen, the device is thus calibrated for a given place.

 A second calibration consists in adjusting the position of the mobile crown as a function of the hourly ratio between the rising and falling periods. For this, Figure 6 illustrates a table which, for reasons of convenience, can be engraved on the back of the upper case 20, giving for each known port of a country its category: A, B, C or D depending on its local relief.

For example, a person residing in Brest turns the mobile outer crown of dial 30 to make the index "BM" in FIG. 3 or "PM" in FIG. 4 coincide with the reference "B".

Thus calibrated, the device according to the invention is available for use. As we could understand on reading the description above, the observer first determines the Vives Eaux, Mortes Eaux or intermediate phase thanks to the first indicator 25 housed in the upper case 20 then, by discovering the second movement , reads the needle up to the arc-circle corresponding to the predetermined period and follows the correction to read the remaining time before the event following high or low tide. By simple addition with the current time read on watch 22, he can easily deduce the exact moment of this next event. Obviously, if we are in a period of
Vives Eaux, no correction is to be made and the reading is therefore direct.

 In the event that the observer moves from one port to another, it is advisable, after having estimated the time of the desired event in relation to his port of departure, to make a correction for the port of arrival by consulting the table shown in Figure 6 engraved on the bottom of the upper case 20. For example, if this observer leaves Le Havre with a 6 hour time difference from Brest, to go to Calais with a 7:40 hour time difference always by compared to Brest1, he will easily understand that he will have to add 1 hour 40 minutes compared to his estimate of the port of departure to obtain that for the port of arrival.

 Obviously, the two watch movements can be mechanical but, for considerations of precision and reliability, the use of quartz watch movements is currently preferred. In a pendulum, we can consider a single watch movement driving a train of cogwheels and pinions for a conventional watch, a phase of the moon and a tide cycle respectively. Many other variants can be made to this device in the context of this invention.

Claims (8)

1. Device indicating the tide schedule comprising a watch movement to rotate an indicator in front of a graduated dial characterized in that it comprises - a first indicator (25) rotating at the rate of a revolution in 59 days before a graduation (27) calibrated according to the White Water, Dead Water and intermediate periods, - a second indicator (37) rotating at the rate of a revolution in 12 hours 25 minutes and 14 seconds in front of a circular graphic assembly (35,36) representing the time remaining before a Full Sea or Low Sea depending on the period of White Water, Dead Waters and intermediate periods. 2. Tide hour indicator device according to claim 1, characterized in that the second indicator (37) is a needle and in that the corresponding graphic assembly comprises two graphic subsets: the first (35) on the external right part of the dial being formed by the intersection of a series of concentric arcs of circle (42) with an apex angle between 1800 and 250 ° which start jointly from a radius (41) oriented towards the top of the dial, and a series of oblique lines (44) oriented in the direction of movement of the needle starting from the internal semicircle corresponding to the periods of Dead waters towards the external arc corresponding to the White Water periods which is completed by a regular graduation (46) in time remaining before the next Low Sea, the oblique lines (44) representing the corrections in decreasing time remaining for other periods; the second sub-assembly (36) similar to the first occupying the internal left part of the dial with the radii of the arcs-of-circles (43) smaller than those of the first and ending jointly on the starting radius (41), the arc -of outer circle corresponding to the White Water periods being completed by a regular graduation (47) in time remaining before the next Full Sea. 3. Device indicating the tide schedule according to claim 2, characterized in that the graduation (46) regular in time of the external arc of the first graphic subgroup (35) is produced on a crown mobile allowing to modify the hourly rise-fall ratio of the tide according to the desired place as indicated by markings (45). 4. Device indicating the tide schedule according to claim 1, characterized in that the graphic assembly comprises two concentric hourly graduations (56, 57) denominated in the same direction, and in that the indicator is presented under the form of two opposite circular sectors rotating at their common apex, the radius of the first sector (53) corresponding to the radius of the internal graduation (56) for the time remaining before Low Sea, the radius of the second sector (54) corresponding to the radius of the external scale (57) for the time remaining before Full Sea, each edge in a semicircle carrying a series of marks (52) corresponding respectively to the periods of Vives-Eaux to Mortes-Eaux 5. Tide hour indicator device according to claim 4, characterized in that the two circular indicator sectors (52, 53) are produced on an eccentric disc (58) rotating. 6. Tide hour indicator device according to claim 4 or 5, characterized in that the external hourly graduation (57) is carried out on a mobile crown making it possible to modify the hourly rise-fall ratio of the tide according to the desired location as indicated by landmarks (55). 7. Device indicating the tide schedule according to one of the preceding claims, characterized in that it is associated, in a wristwatch (10), with a second watch movement (22) rotating on a solar rhythm, the upper housing (20) is folded over the lower housing (30) of the device by rotation around a hinge (15). 8. Device indicating the tide schedule according to claim 7, characterized in that the back of the case (20) of the second movement comprises an engraved table indicating the correction as a function of the place due to the cotidal wave.