Mechanism for displaying time markers, comprising a radially rotatable pointer organ

Abstract

A mechanism (1) for displaying markings (R) arranged chronologically, at least partially around a main axis (3), in a direction along a substantially planar path, comprising a support element (15) arranged to rotate about said main axis (3), drive means (17, 18) for said support element (15), an indicator member (5), translational guide means (25) integral with the support element (15) and in contact with the indicator member (5), a movable cam (30), and elastic return means (26) integral with the indicator member (5) to keep it constantly in contact with the profile of the cam (30), so that the movement of the indicator member (5) results from the combination of the relative movements of said support element (15) and said cam (30), which are selected so that the indicator member (5) moves past said markings (R) at the desired speed, characterized in that marked,that the mechanism (1) comprises reduction means (20) for kinematically connecting the cam disc (30) to the support element (15), and that a cam follower (35) for bringing the indicator member (5) into contact with the profile of said cam disc (30) is connected to a flexible element (40) which grants it a degree of freedom to bend in a direction substantially perpendicular to the plane in which the markings are arranged, and that the cam disc (30) comprises at least one safety groove (34, 34') designed so that the cam follower (35) engages therein as soon as this cam follower is moved in said direction perpendicular to the plane in which the markings are arranged by an arresting element (37), in order to enable it to return to the starting point (31) of the cam disc (30) via a secondary path (36).

Description

[0001] The present invention relates to a mechanism for displaying markers, particularly for equipping the display of a timepiece, preferably a wristwatch. This mechanism has the characteristic of comprising a radially rotatable pointer organ that allows the sequential display of a plurality of markers on the dial, arranged at different distances from the center thereof.

[0002] Calendar events, such as the date, are traditionally displayed on a disc on the outer edge on which the daily information is arranged. To ensure the daily information appears as large as possible and is therefore easy to read, a disc with almost the largest diameter that can be accommodated in the watch case is normally used as the support element. The daily date can be displayed by a central hand or, more generally, in a display window, most commonly located at three o'clock on the dial. However, the maximum size of the numerals forming the daily date is limited to the surface area of a band divided into 31 equal parts on the outer edge of the disc serving as the support element.

[0003] Although less common than the daily data, the display of the days of the week or the months of the year is often truncated or displayed very small, since a larger number of letters of the alphabet have to be arranged on the outer edge of the support element.

[0004] Of course, this problem is even more prevalent with small timepieces, especially pocket watches or wristwatches.

[0005] However, regardless of the size of the dial, other problems can arise when reading markings displayed on the dial. For example, the use of an indice regularly distributed around the edge, each associated with a pair of numbers indicating the twenty-four hours of the day, is recommended. Thus, all hours separated by an interval of twelve hours (for example, ten o'clock and twelve o'clock) are indicated by the same index. Although everyone naturally distinguishes between day and night, there is no other biological clue than this to determine which of the two numbers should be read. To solve this problem, it is known to add a supplementary day / night indication to clarify which number should be read.

[0006] Another way to display the twenty-four-hour division of the day is to divide the dial into 24 parts and assign each a marker corresponding to an hour. The main disadvantage of this display is that everyone is accustomed to reading a conventional clock with hands. In this case, it becomes almost impossible to read the time quickly and without considerable effort, since the first twelve hour divisions are distributed not over 360° but over the first half of the dial.

[0007] ES 2 160 002 A1 discloses a wristwatch in which the hour hand performs its usual rotary movement, but at the same time is movably mounted by a spring so that it can display the spirally arranged 24-hour markings in a radially displaceable manner.

[0008] DE 525 062 A also proposes to mount the hour hand in a radially displaceable manner, thus enabling it to perform radial movements in addition to the rotary movement in order to display spirally arranged 24-hour markings.

[0009] The aim of the present invention is to at least partially solve the aforementioned problems and to provide a more flexible display mechanism that allows for the direct and seamless display of an index or a mark in a sequence of several marks, preferably, but not exclusively, on more than one circumference of the dial. In the latter case, the marks could be arranged in a spiral shape, so that several marks would be arranged in the same, even very acute, angular range, with at least the apex of the angle being close to the center of the spiral.

[0010] According to the invention, the mechanism for displaying such markings comprises an indicator, typically a pointer, capable of radial movement, namely an expanding / retracting movement producing a telescopic effect, as well as a rotational movement, so that each of the markings displayed on the dial can be precisely displayed. Preferably, the rotational movement of the indicator is generated by translation thereof on a support element, the rotation of the latter performing the aforementioned rotational movement.

[0011] According to the embodiment of the invention, the rotary motion is generated by a cam disc whose profile is read by a cam follower integral with the pointer organ. The rotary motion is achieved by connecting the support element of the pointer organ to a rotational axis of a pointer wheel. The latter is set to a speed that depends on the type and distribution of the time markers on the dial. It is obvious that the speed will be different if the markers indicate the 24 hours of a day or the days of a month. It is also conceivable that if such markers are arranged along a spiral with four turns over 360°, the speed would have to be twice as high as if the same markers were distributed over 360° along a spiral with only two turns.

[0012] The relationship between the radial travel speed of the indicator and its rotational speed depends on two parameters. The first parameter is related to the shape of the cam profile. More precisely, and in the case of a spiral cam profile, this parameter depends directly on the tangential polar angle, which, at a point, forms the intersection of the tangent of this profile with the straight line connecting the tangent point to the center of the curve. The larger the angle compared to a right angle, the more pronounced the radial travel. In other words, if the straight line passing through the center of the curve is placed in a vertical plane, the range of radial travel would depend on the slope of the aforementioned tangent.It should therefore be noted that the speed of the radial movement of a pointer organ, which is to follow a coiled, tightly wound spiral, would not be the same speed as if this spiral were wound a little further, with the same number of revolutions.

[0013] In simple terms, the second parameter, taken alone, depends on the difference between the rotational speed of the cam disc and the rotational speed of the pointer. According to the invention, the latter speed is determined by the rotation of the pointer wheel, or at least contributes to it. More specifically, this speed ratio is generated by a transmission gear placed between the pointer wheel and a so-called cam wheel, which is rigidly connected to the cam disc. This speed difference causes the cam follower (connected to the pointer mechanism) to slide on the cam disc.

[0014] Advantageously, the device according to the invention allows for the sequential display of a plurality of markings and / or contiguous indices at different distances from the pivot point of the pointer organ, precisely and avoiding any ambiguity in reading, by directly displaying the specific marking or index. Thanks to such a display mechanism, it is possible to utilize a larger surface area on the dial of a watch to arrange said markings / indices at different distances relative to the pivot point of the pointer organ. Advantageously, this also allows the markings / indices themselves to be larger in size for better legibility.

[0015] Typically, it is possible to double the size of the daily dates by distributing them on two levels around the dial, for example, by distributing them on two spiral arms of a spiral that winds twice around the dial. Taking advantage of a larger surface also eliminates the need to truncate indices, such as the days of the week or the months of the year, which the mechanism is capable of displaying clearly and without any reading uncertainty. By distributing such indices at different distances from the pivot point of the hand, it is advantageously possible to write them using all the letters.

[0016] As an example, the present invention, thanks to its mechanism and its telescopic-effect pointer, allows for the complete display of long astronomical cycles, such as the Metonic cycle, in which the dates of the lunar phases repeat every 19 years. Another example is the possibility of displaying the Saros cycle, used to predict lunar and solar eclipses, where the duration of a complete cycle is 18 years, 11 days, and 8 hours.

[0017] Overall, it should be noted that the mechanism according to the invention enables the display of markings and / or inscriptions without affecting their number, size, quality or legibility, by concentrating these indices on a dial such that the latter could also be of a smaller size, in particular the size of a wristwatch dial.

[0018] Further advantages and specifications will become clear from the following description of the drawings, which refer to a preferred embodiment and which, without being limitative, schematically and by way of example, illustrate the attached figures: The Fig. 1a and Fig. 1b are schematic views in plane showing two different states of the display that can be obtained by the mechanism according to the invention. Fig. 2 is a perspective view of the inventive article seen from above. Fig. 3 is a bottom view of the inventive article of Fig. 2. Fig. 4 is a sectional view along the line IV-IV of Fig. 3. Fig. 5 is a sectional view along the line VV of Fig. 3. Fig. Figure 6 is a schematic partial top view illustrating the kinematics of the mechanism according to the invention.

[0019] The Fig. 1a and Fig. 1b show the time marker display system R of the mechanism 1 according to the invention in two different positions.

[0020] Such markings R, shown as an example in these figures, are thirty-one for depicting the daily data and are represented as curved regions which, when arranged adjacent to one another, together form an Archimedean spiral. Since the arrangement of the markings R is by no means limited to the representation of such a spiral, it should be generalized that these markings are arranged chronologically and at least partially around a main axis 3 of the mechanism 1, and that their arrangement occurs only in one direction of rotation along a mainly planar path that is either non-circular or circular and offset from the main axis 3.

[0021] The markings R are indicated by an indicator organ 5, represented here as a hand, which is driven by the mechanism 1 in rotation and radial translation relative to the main axis 3. As in a watch mechanism in which the hands point to the hour and minute markings to indicate the time, the mechanism 1 is also designed to ensure perfect correspondence between the indicator organ 5 and the nature of the markings R which it is intended to indicate successively.

[0022] Fig. Figure 1a shows a display of mechanism 1 at a time t1. In this first position, it can be seen that the indicator organ 5 points to the nineteenth day of the month, or more precisely, to the second part of this day. In comparison, Fig. Figure 1b shows a similar representation at a second time t2, subsequent to the first; here it should be noted that the indicator organ currently points to the twenty-fourth day of the month, specifically to the end of that day. Between times t1 and t2, the indicator has successively indicated all the days lying between the two aforementioned dates and, to do so, it has performed a double movement, namely a clockwise rotational movement and, at the same time, a radial translational movement relative to the major axis 3, so that one end of the indicator has moved away from the axis, with respect to its tip, by a distance corresponding to one spiral pitch, that is, by a distance equal to the distance between two adjacent spiral arms.

[0023] The following description will describe the mechanism that enables such a display in more detail.

[0024] The Fig. 2 and Fig. 3 show the mechanism 1 in a simplified form, without the markings R and their display, in a perspective view from above and the corresponding view from below. Fig. 4 and Fig. 5 correspond to vertical sectional views, along lines IV-IV and VV, as in Fig. 3. As already mentioned in Fig. As aptly illustrated in Figure 2, the pointer member 5 is held by a support element 15, which is shown in the form of a platform. This comprises a slide rail comprising two pairs of rollers arranged on either side of the pointer member 5 and forming a guide means 25.

[0025] How even better in Fig. As shown in Figure 4, the support element 15 is driven to rotate by a sleeve 16 mounted on the main axis 3 by means of at least one pointer wheel 17, so designated due to its connection to the pointer organ 5 via the support element 15. This pointer wheel is itself rotated by a drive means 18, which provides the necessary energy to rotate the mechanism 1.

[0026] Related to Fig. 3 and the sectional view in Fig. 4, it can be seen that the pointer wheel 17 is connected to a movable reduction 20, more precisely to a gear 22 fixed to a wheel 21. The wheel 21 and the pinion 22 of the movable gear 20 are concentric with the rotation axis 2. This movable gear 20 is intended to rotate a cam disc 30, the non-circular profile of which is in the Fig. 2 and Fig. 3, at a speed different from that of the support element 25. The profile of the cam is read by a cam follower 35, shown in the form of a pin, which serves as the cam reading finger. This cam follower 35 is integral with the indicator member 5 and is located approximately one-third of this member, more precisely, at the third of the end intended to indicate the marks R.

[0027] The pointer member 5, on which the cam follower is mounted, is subjected to the force of an elastic return means 26 to ensure permanent contact between the cam follower 35 and the cam disc 30. This return means 26 is mounted against a retaining means 27 integral with the pointer member 5. Its ends are secured to the support element 15 by a fastening means, for example, screws 28. According to a preferred embodiment, the retaining means 27 is advantageously formed by the free end of the pin serving as the cam follower 35. As shown in the attached figures, the elastic return means 26 is formed by at least one spring, in particular by a spring whose constant changes only slightly over time, in particular over several decades.

[0028] According to a preferred embodiment illustrated in the accompanying figures, the gear 22 of the movable gear member 20 is configured to rotate the cam disc 30 via the interposition of a cam wheel 23 fixed to the cam disc. Advantageously, the cam wheel 23 and the pointer wheel 17 are arranged concentrically with each other around the annular piece 16 and thus have the main axis 3 as their axis of rotation. It should be noted that the cam wheel 23 is mounted idling on the sleeve 16 without any further connection to this axis.

[0029] As a variant, it would be possible to rotate the cam wheel 23 about another axis in order to reduce the thickness of the mechanism and thus create space to extend the kinematic chain of the mechanism 1.

[0030] Referring to Fig. 6, which represents the kinematics of the mechanism according to a partial schematic view from below, the profile of the cam disc 30 is designed such that the indicator member 5, during the reading of the profile, by means of the cam follower 35, constantly moves away from the main axis 3 between a starting point 31 and an end point 32 of the profile.

[0031] Nevertheless, the profile of the cam disc 30 can also be designed in such a way that the pointer organ 5 performs a sequence of distances and approaches in relation to the main axis 3 during its angular movement.

[0032] The function of the mechanism described above is now explained using the Fig. 4 and Fig. 5. The pointer wheel 17, which is driven by the movable drive element 18, itself drives the support element 15 thanks to the sleeve 16 kinematically connected to these two elements. According to the preferred embodiment, the tube or sleeve 16 is riveted to the pointer wheel 17 on one side and is pressed onto the support element 15 of the pointer element 5 on the other.

[0033] The pointer wheel 17 drives the deflecting movable reduction 20 via the wheel 21. The gear 22 of this part then drives the cam wheel 23, which rotates freely around the sleeve 16. This cam wheel 23 is connected to the shaft 16 by a screw 33 ( Fig. 5 and Fig. 6) is attached to the cam disc 30, which also allows fine adjustment of the position of the cam disc on the cam wheel. As in Fig. As shown in Figure 2, the indicator 5 is held on its support element 15 by pairs of rollers 25. These allow translational movement in a direction corresponding to the longitudinal axis of the indicator 5. This axial translational movement, perpendicular to the main axis 3, is subject to a counteracting force caused by the elastic return means 26, which transmits a backward movement to the indicator by resting on the latter. This action creates permanent contact between the cam follower 35 and the flank of the cam disc 30.

[0034] The pointer member 5, mounted on the support element 15, is driven according to a first rotational movement at a speed corresponding to the rotational speed of the pointer wheel 17. Simultaneously, the pointer member 5 is also driven according to a second radial translational movement by the rotational movement of the cam disc on the cam follower 35. The range of this radial movement thus directly depends on the profile shape of the cam disc and its rotational speed. The latter is determined, in a ratio dependent on the speed of the pointer wheel 17, by the movable reduction gear 20, in particular by the ratio of the diameters of the wheel 21 and the gear 22.

[0035] As intended for its main use, the mechanism 1 is dimensioned such that the transmission ratio between the pointer wheel 17 fixed to the pointer organ 5 and the movable part 23 fixed to the cam disc 30 determines the number of revolutions of the pointer organ 5 about the main axis 3.

[0036] For example, if the said ratio is equal to 0.8, the indicator 5 performs five revolutions, while the cam disc only performs one revolution. In other words, it can be concluded that the indicator 5 moves at a speed 20% higher than the cam disc. This causes the cam follower 35 to slide on the flank of the cam disc during the rotation of the indicator. As a result, and according to the values given here as an example, the indicator must perform five revolutions for the cam follower itself to travel the entire length of the flank of the cam disc, i.e. the distance between the starting point 31 and the end point 32 of the cam disc profile ( Fig. 6). Once the cam follower has reached the end point 32, the indicator member 5 returns, under the action of the elastic return means 26, to its initial position, which corresponds to the positioning of the cam follower at the initial point 31. This immediate return is made possible by the property of the cam disc 30, which is an instantaneous jump cam.

[0037] In order to avoid any damage to the mechanism in case it were to rotate in the opposite direction to the normal direction of rotation of the indicator organ, it is additionally provided that the latter comprises a safety mechanism which allows the cam follower 35 to prevent the path defined by the cam flank from being cut off and a second path 36 ( Fig. 6), which is a shortcut to the starting point 31.

[0038] For this purpose and as described in the Fig. 2 and Fig. 6, the cam follower is connected to a flexible element 40 which gives it a degree of freedom to bend in a direction substantially perpendicular to the plane in which the Fig. 1a and Fig. 1b. According to the preferred embodiment, the recess 40 is obtained by forming a slot 41 extending through the indicator member 5. This slot 41 runs around the cam follower and then extends near the same toward the outside of the flank of the indicator member 5.

[0039] Furthermore, the cam disc 30 includes at least one groove 34, 34', a so-called safety groove, which the cam follower 35 can take after being brought into the aforementioned, substantially vertical direction by a locking member 37, so that the cam follower can reach the starting point 31 of the cam disc profile even more quickly. According to the preferred embodiment, the locking member 37 can simply be formed by an inclined plane.

[0040] Overall, the profile of the cam disc 30 is in no way limited to reproducing a constant distance movement of the pointer organ or to a linear increase in this distance, as is the case when the markings are arranged along an Archimedean spiral.

[0041] If the cam profile is modified, it would also be possible for the indicator organ to follow a differently shaped spiral, in particular a logarithmic spiral, also called an equiangular spiral due to its constant polar tangent angle (not right angle), or a growth spiral due to its variable rise.

[0042] Very generalized and theoretically speaking, mechanism 1 allows any marking to be displayed in chronological order along a single direction of rotation according to a polar coordinate system whose starting point is centered on the main axis 3. The two polar coordinates of such a system, defined by an angle and a distance from this starting point, can be obtained by the indicator organ thanks to its rotation and axial translation, which allow it to perform a combined movement.

[0043] Although the cam disk profile 30 has been shown with a flat, uniform surface, it is also conceivable that this profile could be designed in a stepped manner with several layers, so that the pointer organ 5 would exert a jumping effect, which would regularly manifest itself as a short acceleration when passing two adjacent markings R.

[0044] As a variant, and still aiming to give the pointer a retracting / expanding effect, it would also be possible to achieve a comparable radial movement using a truly telescopic device, i.e., one composed of several interlocking and sliding elements. In this case, it would be conceivable to omit the support element for the pointer; the latter could then, for example, be arranged to rotate directly around the main axis.

[0045] Although the subject matter of the present invention also includes the use of a mechanism 1 with a display of markings R distributed over more than 360° on the same dial or on different planes, it should be noted that the distribution of the markings is in no way limited to such a range of values, it may also comprise a single revolution on the dial, ie a single rotation unit.

[0046] In a specific application, the mechanism according to the invention could also be used to display twenty-four indices or markers corresponding to the twenty-four hours of a day, evenly distributed over two laps of the dial of a timepiece.

[0047] In other embodiments, the mechanism could also be used to display the days of the week, the months of the year, or cyclical astronomical events, particularly those where the cycles extend over more than a decade.

[0048] Due to the advantage achieved with this inventive mechanism in a compact space, this mechanism is preferably used in connection with wristwatches. However, it should be noted that the subject matter of the invention is in no way limited to the movement of timepieces, but could also be perfectly combined with other types of movements, for example, as a stand-alone object.

Claims

[1] Mechanism (1) for displaying marks (R) arranged chronologically, at least partially around a main axis (3), in a direction along a substantially planar path, comprising a support element (15) arranged to rotate about said main axis (3), drive means (17, 18) for said support element (15), an indicator member (5), translational guide means (25) integral with the support element (15) and in contact with the indicator member (5), a movable cam (30) and elastic return means (26) integral with the indicator member (5) to keep it constantly in contact with the profile of the cam (30), so that the movement of the indicator member (5) results from the combination of the relative movements of said support element (15) and said cam (30), selected so that the indicator member (5) indicates said marks (R) at the desired speed expires, characterized byin that the mechanism (1) comprises reduction means (20) for kinematically connecting the cam disc (30) to the support element (15), and in that a cam follower (35), in order to bring the indicator member (5) into contact with the profile of said cam disc (30), is connected to a flexible element (40) which grants it a degree of freedom to bend in a direction substantially perpendicular to the plane in which the markings are arranged, and in that the cam disc (30) comprises at least one safety groove (34, 34') designed so that the cam follower (35) engages therein as soon as this cam follower is moved in said direction perpendicular to the plane in which the markings are arranged by an arresting element (37), in order to enable it to return to the starting point (31) of the cam disc (30) via a secondary path (36). [2] Mechanism according to claim 1, characterized bythat the profile of the cam disc (30) is designed so that the pointer organ (5) moves away from the main axis (3) while completing the entire cycle of said markings (R). [3] Mechanism according to claim 2, characterized by that the profile of the cam disc (30) is designed such that the removal of the pointer organ (5) increases linearly. [4] Mechanism according to claim 1, characterized by that the profile of the cam disc (30) is designed such that the pointer member (5) performs a gradual distance and approach in relation to the main axis (3) during its angular movement. [5] Mechanism according to claim 1, characterized byin that the reduction means (20) comprise a first movable part (21) driven by the drive means (17, 18) and coaxial with this first movable part (21) a second movable part (22) in contact with the cam disc (30), preferably by interposing a movable part (23) rigidly connected to the cam disc (30). [6] Mechanism according to claim 5, characterized by that the transmission ratio between the movable part (17) connected to the pointer organ and the movable part (23) connected to the cam disc determines the number of revolutions of the pointer organ (5) about the axis (3). [7] Mechanism according to one of claims 1 to 6, characterized by that the two extremities of the cycle described by the cam disc are connected by an element producing an instantaneous jump of the indicator organ. [8] Mechanism according to one of claims 1 to 7, characterized byin that the elastic return means (26) consists of at least one spring, one end of which is fixed to the support element (15) and the other end of which is connected to the indicator member (5), preferably resting against a free end (27) of a cam follower (35) in order to bring the indicator member (5) into contact with the profile of the said cam disc (30). [9] Mechanism according to one of claims 1 to 8, characterized by that the guide means (25) of the pointer organ (5) on its support element (15) is a slide rail. [10] Mechanism according to claim 9, characterized by that said slide rail comprises two pairs of rollers arranged on either side of the pointer member (5). [11] Mechanism according to one of the preceding claims, characterized bythat a slot (41) runs over the pointer member (5), runs closely around the cam follower (35) and extends in the direction of the outer flank of the pointer member (5) and forms the recess (40). [12] Mechanism according to one of the preceding claims, characterized by that the inhibiting element (37) is formed by an inclined plane. [13] Use of the mechanism according to one of the preceding claims for displaying the markings (R) distributed over 360° or more on a single dial. [14] Use according to claim 13 for displaying 24 markings (R), corresponding to the 24 hours of a day, distributed over two 360°. [15] Use according to claim 13 for displaying the days of the week, the months of a year or cyclical astronomical events, in particular with cycles extending over more than a decade. [16] Use according to one of the preceding claims in connection with a wristwatch.

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