Display carriage, movement for timepiece, and timepiece

Abstract

To allow a display carriage to flexibly accommodate various designs of the display portion (display plate) while the gear portion (gear member) is attached to the movement.SOLUTION: A date wheel (display carriage) 10 includes: a date plate (display plate) 20 on which a plurality of characters such as date numerals of a calendar are displayed and which rotates; and an internal gear 30 (gear of a gear member) that is driven by engagement with a drive gear of a movement 100 for a timepiece. The date plate 20 and the internal gear 30 are provided with a snap-fit structure 35 (mechanical fitting structure) by which the date plate 20 and the internal gear 30 are fitted together and integrated.SELECTED DRAWING: Figure 2A

Description

[Technical Field]

[0001] The present invention relates to a display wheel, a timepiece movement, and a timepiece. [Background technology]

[0002] Portable timepieces such as wristwatches not only display the time but also have a calendar function that displays the date and day of the week. In addition to the calendar function, some timepieces also have a function that displays the name of a city in the world where the displayed time is located.

[0003] A timepiece is equipped with a display wheel such as a date indicator to display the date, day of the week, city name, etc. (hereinafter referred to as the date, etc.). The display wheel has a display section and a gear section. The display section displays a plurality of letters and symbols (hereinafter referred to as the letters, etc.) of the date, etc. to be displayed. The gear section meshes with a drive wheel provided in the movement to rotate the display wheel. As a result, the display wheel displays the date, etc., by making one of the plurality of letters, etc. displayed in the display section, corresponding to the rotated position, visible from the outside through a display window formed at a predetermined position on the dial (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-190297 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, the orientation of the characters, etc. written in the display unit needs to be changed depending on the position of the window formed in the dial. That is, when the window is formed at the 3 o'clock position, the characters, etc. need to be written upside down relative to the display unit compared to when the window is formed at the 9 o'clock position. Similarly, when the window is formed at the 3 o'clock position, the characters, etc. need to be written in a 90-degree rotated orientation compared to when the window is formed at the 6 o'clock position. In addition, the font design of the characters, etc. written in the display unit is often changed depending on the design of the dial.

[0006] Therefore, there are many different types of display wheels, each differing only in the design of the display portion. From these many different types of display wheels, one that matches the specifications of the dial, etc. is selected and attached to the movement.

[0007] Here, in the timepiece manufacturing process, the task of attaching the indicator wheel to the movement requires precise adjustment of the meshing between the gear of the indicator wheel and the drive wheel of the movement. In other words, if this meshing precision is poor, the positional relationship between the dial window and the characters on the indicator wheel will be misaligned, resulting in a deterioration in the appearance quality. Therefore, it is preferable that the indicator wheel be attached to the movement during the movement assembly process, which requires assembly precision. The movement with the attached indicator wheel is then sent to the final product assembly process, where it is combined with the watch case, crystal, dial, case back, etc. and assembled into the finished timepiece.

[0008] However, as mentioned above, the characters written on the display wheel are pre-selected to correspond to the design of the dial to be combined with it. However, if, during the assembly process of the finished product, when the movement to which the display wheel is attached is combined with the dial, it is discovered that the characters on the display wheel are not the correct characters to be combined with the dial, a correction work is required in which the display wheel is removed from the movement and reassembled with a display wheel with the correct characters.

[0009] As such, the display wheel is required to have a gear section that can be attached to the movement with high precision, and the display section that can flexibly accommodate a variety of designs.

[0010] The present invention has been made in consideration of the above circumstances, and aims to provide a display wheel, a timepiece movement equipped with a display wheel, and a timepiece equipped with a display wheel, which can flexibly adapt the display section (display board) to various designs when the gear section (gear component) is attached to the movement. [Means for solving the problem]

[0011] The first aspect of the present invention is a display wheel that rotates and displays multiple characters, etc., and comprises a display plate on which the characters, etc. are displayed, and a gear member having a gear that is driven by meshing with the drive teeth of a timepiece movement, and the display plate and gear member are equipped with a positioning portion that positions the display plate and the gear member in a predetermined positional relationship, and a mechanical fitting structure that fits the display plate and the gear member together to form a single unit.

[0012] A second aspect of the present invention is a timepiece movement equipped with a display wheel according to the present invention.

[0013] A third aspect of the present invention is a timepiece equipped with a display wheel according to the present invention. [Effects of the Invention]

[0014] The display wheel, the watch movement equipped with the display wheel, and the watch equipped with the display wheel of the present invention can flexibly accommodate a variety of designs for the display section (display board) when the gear section (gear member) is attached to the movement. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a perspective view showing the movement with the date indicator attached. [Figure 2A] FIG. 10 is a plan view showing the front surface of the date indicator. [Figure 2B]FIG. [Figure 2C] FIG. 2B is a partial perspective view including a cross section taken along line AA in FIG. 2A. [Figure 2D] FIG. 2B is a partially enlarged view showing the details of part B in FIG. 2A. [Figure 2E] FIG. 2E is a cross-sectional view showing a cross section taken along line CC in FIG. 2D. [Figure 2F] FIG. 2E is a cross-sectional view taken along line DD in FIG. 2D. [Figure 3A] 2B is an exploded perspective view of the date wheel of the date indicator with the internal gear separated from the date wheel, as seen from the front surface side shown in FIG. 2A. FIG. [Figure 3B] 2C is an exploded perspective view showing the date wheel of the date indicator separated from the internal gear, as viewed from the back side shown in FIG. 2B. FIG. [Figure 4A] 10 is a schematic diagram showing an example of the relationship between the window formed at the 3 o'clock position on the dial and the orientation of the date numbers on the date plate. FIG. [Figure 4B] 10 is a schematic diagram showing an example of the relationship between the window formed at the 6 o'clock position on the dial and the orientation of the date numbers on the date plate. FIG. [Figure 5A] 10 is a schematic diagram showing the date plate pressing member, showing the state in which the date plate pressing member is positioned in the pressing position after the screws are tightened and fixed. FIG. [Figure 5B] 10 is a schematic diagram showing the date plate holder with the screw loosened and the date plate holder placed in the retracted position. FIG. [Figure 6] 10 is a schematic diagram showing another example of a date plate pressing member, showing the state in which the date plate pressing member is fixed by a fixing means. FIG. [Figure 7] FIG. 1 is a cross-sectional view showing a timepiece including a movement with a solar cell located closer to the dial than the internal gear. [Figure 8] FIG. 3B is an exploded perspective view showing the date wheel of another embodiment (embodiment 2) of the display wheel according to the present invention, with the date wheel and internal gear of the date wheel separated, as viewed from the back side corresponding to FIG. 3B. [Figure 9A] FIG. [Figure 9B] FIG. 10 is a plan view showing the front surface of the date indicator. [Figure 10] FIG. 9B is a partially enlarged view showing the details of part E in FIG. 9A. [Figure 11A] FIG. 9C is a cross-sectional view taken along line FF in FIGS. 9A and 9B. [Figure 11B] FIG. 9C is a cross-sectional view taken along line GG in FIGS. 9A and 9B. [Figure 11C] FIG. 10 is a cross-sectional view taken along line HH in FIGS. 9A and 9B. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of an indicator wheel, a timepiece movement equipped with an indicator wheel, and a timepiece equipped with an indicator wheel according to the present invention will be described as follows with reference to the drawings.

[0017] <Embodiment 1> Figure 1 is an oblique view showing a timepiece movement 100 (hereinafter simply referred to as movement 100) with a date wheel 10 attached, Figure 2A is a plan view showing the front surface 10a of the date wheel 10, Figure 2B is a plan view showing the back surface 10b of the date wheel 10, Figure 2C is a partial oblique view including a cross section along line AA in Figure 2A, Figure 2D is a partial enlarged view showing details of part B in Figure 2A, Figure 2E is a cross section showing a cross section along line CC in Figure 2D, and Figure 2F is a cross section showing a cross section along line DD in Figure 2D.

[0018] 3A is an exploded perspective view of the date indicator 10 with the date plate 20 and internal gear 30 separated, as seen from the front surface 10a shown in FIG. 2A, and FIG. 3B is an exploded perspective view of the date indicator 10 with the date plate 20 and internal gear 30 separated, as seen from the back surface 10b shown in FIG. 2B. The illustrated date indicator 10 is one embodiment (embodiment 1) of a display wheel according to the present invention, a movement 100 equipped with the date indicator 10 is one embodiment of a timepiece movement according to the present invention, and a timepiece equipped with the date indicator 10 (a timepiece equipped with the movement 100) is one embodiment of a timepiece according to the present invention.

[0019] (Overall structure of the Nissha) As shown in FIG. 1, the date indicator 10 is attached to the movement 100 of the timepiece 200 (see FIG. 7) with the front surface 10a facing outwards. Then, after the date indicator 10 has been attached to the movement 100, a date indicator retaining plate 90 is fixed to the movement 100 from the side of the front surface 10a so as to cover part of the internal teeth 34 of the date indicator 10. Even if an external force such as an impact force acts on the timepiece and causes the date indicator 10 to displace towards the front surface 10a in a direction that would cause it to come off the movement 100, the date indicator retaining plate 90 will come into contact with the internal teeth 34. In this way, the date indicator retaining plate 90 prevents the date indicator 10 from displacing towards the front surface 10a, preventing the date indicator 10 from falling off the movement 100.

[0020] As shown in Figures 2A and 2B, the date indicator 10 is formed in a substantially annular plate shape. The date indicator 10 has a date plate 20 (an example of a display plate) and an internal gear 30 (an example of a gear in a gear member). The date indicator 10 is integrated by fitting or engaging the date plate 20 and internal gear 30, which are formed separately from each other, together through a mechanical structure. Before being integrated into the date indicator 10, the date plate 20 and internal gear 30 are separate, as shown in Figures 3A and 3B.

[0021] (Japanese board) The date dial 20 is formed, for example, in the shape of a substantially circular ring plate centered at C0. The date dial 20 has a flat front surface 20a and a flat back surface 20b, except for two protrusions 21 and 22, which will be described later, and is formed with a constant thickness regardless of its radial position.

[0022] The date dial 20 may be made of either a resin or metal material. Since the date numbers are written on the date dial 20 by printing or the like, it is preferable that the date dial 20 be made of a material that is easy to print on. Furthermore, since the date dial 20 is visible from the outside through a window 71 formed in the dial (see Figures 4A and 4B) when the watch is completed, it is preferable that the date dial 20 be made of a metal material that has better appearance quality (good looks) than resin.

[0023] Conventional date indicators, in which the display portion corresponding to the date dial 20 and the gear portion corresponding to the internal gear 30 are integrally molded, are sometimes made of POM (polyoxymethylene). POM is a material suited to the characteristics required of the gear portion (e.g., high strength, high wear resistance, high temperature stability, lightweight, etc.). However, POM does not lend itself well to printing, so it was necessary to apply a primer treatment to the display portion to improve printability.

[0024] However, the effectiveness of the surface treatment that improves printability decreases over time, so time management from surface treatment to printing was necessary. Also, if the date wheel was made of metal from the perspective of appearance quality, the gear part would also be made of metal, which would result in a problem of being heavier than POM material.

[0025] In contrast to this, in the date indicator 10 of embodiment 1, the date dial 20 and the internal gear 30 are formed from separate members. Therefore, in the date indicator 10, the date dial 20 can be formed from a material suited to the characteristics required for the display unit (good printability, good appearance quality, etc.), and the internal gear 30 can be formed from a material suited to the characteristics required for the gear unit. In other words, in the date indicator 10, the date dial 20 and the internal gear 30 can be formed from different materials.

[0026] Figure 4A is a schematic diagram showing an example of the relationship between the window 71 formed at the 3 o'clock position on the dial 70 and the orientation of the date numbers written on the date plate 20, and Figure 4B is a schematic diagram showing an example of the relationship between the window 71 formed at the 6 o'clock position on the dial 70 and the orientation of the date numbers written on the date plate 20.

[0027] The date dial 20 has 31 numbers (1, 2, ..., 30, 31) representing, for example, calendar dates written on its front surface 20a (the surface visible in Figs. 2A and 3A) which corresponds to the front surface 10a of the date wheel 10 (see Figs. 4A and 4B). The 31 numbers on the date dial 20 are written at equal angular intervals around the center C0 of the ring, aligned along the circumferential direction of the ring.

[0028] As shown in Figures 2B and 3B, two cylindrical protrusions 21 and 22 are formed on the back surface 20b of the date dial 20. As shown in Figures 3A and 3B, the two protrusions 21 and 22 are formed at positions equidistant from the center C0 with an angular interval α of, for example, 175 degrees around the center C0.

[0029] The angular interval α between the two protrusions 21, 22 is not limited to 175 degrees, and may be 170 degrees or 160 degrees, although an angle other than 180 degrees is preferable. The reason why the angular interval α between the two protrusions 21, 22 is set to an angle interval other than 180 degrees is to regulate the circumferential positional relationship around the center C0 between the date dial 20 and the internal teeth 34 of the internal gear 30 when combining the date dial 20 and the internal gear 30 to form an integrated date indicator 10, thereby preventing incorrect assembly.

[0030] The two protrusions 21, 22 may also be arranged at different distances from the center C0. In this case, the angular interval α between the two protrusions 21, 22 on the date dial 20 may be 180 degrees, which can prevent incorrect assembly.

[0031] In particular, in the process of assembling the date dial 20 to the internal gear 30 when the internal gear 30 is already assembled in the movement 100, the circumferential position of the internal gear 30 about the center C0 is determined to a predetermined position by the movement 100. Therefore, when assembling the date dial 20 to the internal gear 30 that is assembled in the movement 100, it is important to align the angular positions of the date dial 20 and the internal gear 30 in the circumferential direction about the center C0.

[0032] 3A and 3B, the date dial 20 has a notch 28 formed in part of the outer peripheral edge 20e. The notch 28 penetrates in the thickness direction from the front surface 20a to the back surface 20b. The notch 28 is formed so that its positional relationship in the circumferential direction around the center C0 with respect to the two protrusions 21, 22 formed on the back surface 20b is a predetermined positional relationship that has been set in advance.

[0033] The date dial 20 is positioned in a specific positional relationship with the internal gear 30 by inserting the two protrusions 21 and 22 into the hole 36 and notch 37 of the internal gear 30, so the date numbers on the front surface 20a of the date dial 20 need to be written in a specific positional relationship with the protrusions 21 and 22.

[0034] However, since the protrusions 21 and 22 are formed on the back surface 20b of the date dial 20, the positions of the protrusions 21 and 22 cannot be seen from the front surface 20a on which the date numbers are written, and there is a possibility that the position on which the date numbers are written may shift circumferentially.

[0035] In contrast, the notch 28 is visible from the front surface 20a. The notch 28 is formed in a predetermined positional relationship with the two protrusions 21, 22. Therefore, in the process of writing the date numerals on the front surface 20a, the date dial 20 can write the date numerals in a predetermined positional relationship with the notch 28, using the notch 28 as a reference.

[0036] As a result, the date numerals on the date dial 20 are written in positions that are in a predetermined positional relationship with the protrusions 21, 22. Therefore, when the date dial 20 is combined with the internal gear 30, the positions of the date numerals on the date dial 20 can be prevented from shifting circumferentially relative to the internal gear 30.

[0037] As such, since the notch 28 only needs to be a mark that can be seen from the front surface 20a, the mark does not have to be a notch 28 that penetrates all the way to the back surface 20b, but may be in the form of a groove or protrusion that does not penetrate all the way to the back surface 20b. If a protrusion is provided as a mark, it must be formed with dimensions that do not make contact with the dial, etc. By providing a protrusion, for example, in the event of an impact, the protrusion will come into contact with the dial, preventing the date dial 20 from falling off the internal gear 30.

[0038] These notches 28 and other markers are formed in positions that cannot be seen from the outside through a window 71 (see Figures 4A and 4B) in the dial 70 (see Figure 7) of the timepiece 200 when the date wheel 10 is completed as the timepiece 200.

[0039] If there is a jig that can position the date dial 20 by inserting the protrusions 21, 22 on the back surface 20b of the date dial 20, the date dial 20 can be set in the jig and the date numbers can be written on the front surface 20a. In this case, the date dial 20 does not need to have a mark such as the notch 28 that is visible from the front surface 20a.

[0040] The end face of the date dial 20, which is its inner peripheral edge 20c, forms an end face 20d that is inclined with respect to the thickness direction (the vertical direction in the figure) around the entire circumference, as shown in Figures 2E and 2F. Specifically, the distance from the center C0 to the inner peripheral edge 20c1 (inner peripheral edge 20c) on the front surface 20a of the date dial 20 is formed slightly longer than the distance from the center C0 to the inner peripheral edge 20c2 (inner peripheral edge 20c) on the back surface 20b. As a result, the end face 20d intersects with the back surface 20b at an acute angle and with the front surface 20a at an obtuse angle, and is a surface that faces vertically upward and radially inward as shown.

[0041] (internal gear) Like the date dial 20, the internal gear 30 is formed, for example, in the shape of a substantially circular ring plate centered at C0. The internal gear 30 may be made of a resin material or a metal material. From the perspective of the characteristics required of a gear portion, the internal gear 30 is preferably made of a POM material, for example. The internal gear 30 does not have an axis aligned with the center C0, but is rotatable around the center C0.

[0042] The internal gear 30 is formed to have a smaller outer diameter than the date dial 20. The date dial 20 is formed with a uniform thickness, but the internal gear 30 is formed with a thickness that varies depending on the radial position.

[0043] 2C, the internal gear 30 has an inner peripheral portion 31, an outer peripheral portion 32, and internal teeth 34. The inner peripheral portion 31 is the thickest portion of the internal gear 30. The outer peripheral portion 32 extends radially outward from the inner peripheral portion 31 and is formed to be thinner than the inner peripheral portion 31.

[0044] As shown in Fig. 2C, the back surface 31b of the inner peripheral portion 31, which corresponds to the back surface 10b of the date indicator 10 (see Fig. 2B), and the back surface 32b of the outer peripheral portion 32, which corresponds to the back surface 10b of the date indicator 10, are formed flush with each other without any steps, forming the back surface 30b of the internal gear 30. On the other hand, a step is formed between the front surface 31a of the inner peripheral portion 31 and the front surface 32a of the outer peripheral portion 32, corresponding to the difference in thickness between the inner peripheral portion 31 and the outer peripheral portion 32, and the internal gear 30 has a step surface 33 at the boundary between the inner peripheral portion 31 and the outer peripheral portion 32, which corresponds to the difference in thickness between the inner peripheral portion 31 and the outer peripheral portion 32. The step surface 33 extends in the thickness direction of the internal gear 30 (the vertical direction in the drawing), except for the portion of a snap fit 35, which will be described later.

[0045] The difference in thickness between the inner peripheral part 31 and the outer peripheral part 32 of the internal gear 30 is set to be equal to the thickness of the date dial 20. Furthermore, the internal gear 30 is formed so that the radius from the center C0 to the step surface 33 is approximately equal to the radius of the date dial 20 from the center C0 to the inner peripheral edge 20c.

[0046] Therefore, the date dial 20 can be placed on the front surface 32a of the outer peripheral portion 32 with the inner peripheral edge 20c of the date dial 20 positioned outside the stepped surface 33 of the internal gear 30, and the back surface 20b of the date dial 20 in contact with the front surface 32a of the outer peripheral portion 32. In this case, the front surface 31a of the inner peripheral portion 31 (the exposed front surface 30a of the internal gear 30) and the front surface 20a of the date dial 20 are flush with each other with no steps.

[0047] The difference in thickness between the inner circumferential portion 31 and the outer circumferential portion 32 of the date indicator 10 does not have to be equal to the thickness of the date plate 20. If the date plate 20 is formed thick and the front surface 20a of the date plate 20 protrudes (is higher) than the front surface 31a of the inner circumferential portion 31, the date plate 20 must be formed with dimensions that prevent the date plate 20 from coming into contact with the dial.

[0048] The internal teeth 34 protrude radially inward from the inner peripheral portion 31 and are provided along the circumferential direction on the inner peripheral edge of the inner peripheral portion 31. When the internal gear 30 is assembled to the movement 100, the internal teeth 34 mesh with a drive wheel that is provided on the movement 100 and is arranged radially inside the internal gear 30, and the internal teeth 34 are driven by the drive wheel, causing the internal gear 30 to rotate around the center C0.

[0049] As shown in Figure 2C, the internal teeth 34 are formed at a position lower than the front surface 31a of the inner peripheral portion 31, and a date indicator holder plate 90 (in Figure 2C, the cross section of the date indicator holder plate 90 is shown by a two-dot chain line) fixed to the movement 100 is positioned above the internal teeth 34.

[0050] 3A and 3B, the internal gear 30 has holes 36 formed in positions corresponding to the two protrusions 21 formed on the date dial 20, and a notch 37 formed in a position corresponding to the protrusion 22. In other words, the hole 36 and the notch 37 are formed at positions where the angular interval α about the center C0 is the same as the angular interval α of the protrusions 21, 22, for example 175 degrees, and where the distance from the center C0 is equal to the distance from the center C0 to the protrusions 21, 22. The notch 37 is formed to extend radially outward from the position corresponding to the protrusion 22 to a position reaching the outer peripheral edge 30c of the internal gear 30.

[0051] As a result, when the date dial 20 is rotated around center C0 relative to the internal gear 30 with the date dial 20 placed on the outer periphery 32 of the internal gear 30, at a specific rotation position the protrusion 21 of the date dial 20 is inserted into the hole 36 of the internal gear 30, and the protrusion 22 of the date dial 20 is inserted into the notch 37 of the internal gear 30. At this specific rotation position, the date dial 20 is positioned circumferentially relative to the internal gear 30, and with the back surface 20b of the date dial 20 in contact with the front surface 32a of the outer periphery 32, the date dial 20 and the internal gear 30 form an integrated date wheel 10.

[0052] In this way, the date indicator 10 can position the date dial 20 and the internal gear 30 in a predetermined positional relationship around the center C0 by means of the two protrusions 21, 22 of the date dial 20 and the hole 36 and notch 37 of the internal gear 30. Therefore, the protrusions 21, 22, the hole 36 and the notch 37 are an example of a positioning portion in the present invention.

[0053] If the positioning of the date dial 20 and the internal gear 30 can be achieved by another means, the two protrusions 21, 22 of the date dial 20 and the hole 36 and notch 37 of the internal gear 30 may be omitted.

[0054] Furthermore, the side of the internal gear 30 into which the protrusion 21 of the date dial 20 is inserted is formed with a hole 36, but the side into which the protrusion 22 of the date dial 20 is inserted is formed with a notch 37 that is radially longer than the hole 36. Therefore, even if there is an accumulation error within the tolerance range in the position of the protrusion 22 relative to the protrusion 21 or the position of the notch 37 relative to the hole 36, the notch 37 can absorb that accumulation error, and when the protrusion 21 is inserted into the hole 36, the protrusion 22 can be inserted into the notch 37.

[0055] The date indicator 10 may also be configured such that the protrusion 21 is formed on the internal gear 30 and the hole 36 is formed on the date plate 20. When the date indicator 10 has a hole 36 formed on the date plate 20, it is preferable that the hole 36 is not a through-hole but a groove that does not pass through to the front surface 20a. When the hole 36 is formed as a through-hole, it is preferable that the through-hole is formed in a position that is not visible to the user through the date window of the dial. The date indicator 10 may also be configured such that one protrusion 21 and one hole 36 are formed on each of the date plate 20 and the internal gear 30, and the protrusion 21 of the date plate 20 is inserted into the hole 36 of the internal gear 30, and the protrusion 21 of the internal gear 30 is inserted into the hole 36 of the date plate 20.

[0056] 2D, the internal gear 30 has a snap fit 35 formed on the front surface 31a of the inner peripheral portion 31. The snap fit 35 is an example of a mechanical fitting structure that fits the internal gear 30 and the date dial 20 together to maintain the integrated state of the date indicator 10.

[0057] As shown in Fig. 2D, the snap fit 35 is formed near the intended position where the snap fit 35 is to be formed, and as shown in Fig. 2E, it is formed by a recess 35a recessed in the thickness direction from the front surface 31a of the inner circumferential portion 31. The snap fit 35 is formed by a radially outer wall portion of the recess 35a, and this wall portion is capable of elastically deforming inward of the recess 35a.

[0058] Snap fit 35 is configured such that, on the outer wall of recess 35a described above, vertically extending step surface 33 shown in Fig. 2F is replaced with step surface 33a that is inclined vertically downward and radially outward as shown in Fig. 2E, along inclined end surface 20d on the inner peripheral edge 20c side of date dial 20. In a state where no external force is acting on snap fit 35, inclined step surface 33a is in contact with inclined end surface 20d.

[0059] 2A, the snap fits 35 are formed at, for example, four positions (for example, four positions distributed at angular intervals of 90 degrees around the center C0) around the circumferential direction of the internal gear 30 about the center C0. The internal gear 30 needs to have at least two snap fits 35 formed around the center C0, and from the viewpoint of circumferential balance around the center C0, it is preferable that three or more snap fits are formed in an arrangement surrounding the center C0.

[0060] When there are two snap fits 35, they are preferably formed at positions spaced 180 degrees apart from the center C0. When there are three or more snap fits 35, they are preferably formed so that the center C0 is located inside a polygon formed by connecting the snap fits 35 with imaginary line segments (a triangle when there are three snap fits 35, a rectangle when there are four snap fits 35, etc.), that is, so that the snap fits 35 are arranged to surround the center C0.

[0061] With the back surface 20b of the date dial 20 in contact with the front surface 32a of the outer periphery 32 of the internal gear 30 and the date dial 20 positioned on the internal gear 30 in a specific positional relationship, the four snap fits 35 each contact the end face 20d of the inner peripheral edge 20c of the date dial 20, pressing the date dial 20 downward and radially outward. This holds the date dial 20 and internal gear 30 in a fitted state.

[0062] On the other hand, because the snap fit 35 is capable of elastic deformation inward of the recess 35a, an external force can be applied by hand, a jig, or the like to cause the snap fit 35 to elastically deform inward of the recess 35a. In this state, the step surface 33a of the snap fit 35 is separated radially inward from the end face 20d of the date dial 20. This releases the date dial 20 from downward and radially outward constraints. In this way, the date indicator 10 allows the date dial 20 to be removed from the internal gear 30, and the date dial 20 can also be fitted into the internal gear 30.

[0063] In this way, the date indicator 10 can be configured such that the date dial 20 and the internal gear 30 are fitted together as a single unit by means of the snap fit 35 formed on the internal gear 30, the support surface that supports the date dial 20 (the inclined step surface 33a (or step surface 33) and the front surface 32a of the outer periphery 32), and the inclined end surface 20d formed on the date dial, and the integrated date dial 20 and internal gear 30 can also be separated into separate pieces.

[0064] As explained in detail above, in the date indicator 10 of Embodiment 1, the date dial 20 and the internal gear 30 are each formed as separate members, and therefore the date dial 20 and the internal gear 30 can be formed from materials suited to their respective requirements. Moreover, in the date indicator 10 of Embodiment 1, the date dial 20 and the internal gear 30 are integrated by a mechanically fitted structure, and therefore the date dial 20 and the internal gear 30 can be detached.

[0065] A mechanical interlocking structure is a structure in which two or more components are integrated by interlocking or engaging parts of their shapes with each other, and can be separated (detachable) by releasing the interlocking or engagement.

[0066] In the date wheel 10 of embodiment 1, instead of or in addition to a mechanical interlocking structure, in order to improve impact resistance and to make disassembly impossible after mechanical interlocking, the date dial 20 and the internal gear 30 may be bonded together using an intermediary such as an adhesive or pressure sensitive adhesive, or may be welded together by melting a portion of at least one of the date dial 20 and the internal gear 30 using heat or ultrasonic vibration.

[0067] More precisely, the date wheel 10 of embodiment 1 includes not only the snap fit 35 as a mechanical fitting structure, but also the inclined end face 20d formed on the date plate 20 and the support surface formed on the internal gear 30.

[0068] However, the mechanical fitting structure in the display wheel of the present invention is not limited to a structure including an inclined end surface 20d formed on the date dial 20 and a support surface formed on the internal gear 30, nor is it limited to a snap fit 35.

[0069] Therefore, for example, if a mechanical fitting structure is applied in which the end face of the inner peripheral edge 20c of the date dial 20 is directly fitted into the internal gear 30, the internal gear 30 does not need to have an outer peripheral portion 32. However, it is preferable to have the outer peripheral portion 32 of the internal gear 30, as this supports the date dial 20 from below in the surface direction, thereby enabling the date dial 20 to be stably supported.

[0070] Furthermore, since the date plate that constitutes the date wheel 10 is a substantially flat plate, setting the date wheel 20 when writing the date numbers is easier than with an integrated date wheel that includes a gear portion, which simplifies manufacturing.

[0071] In the date indicator 10 of Embodiment 1, the date plate 20 and the internal gear 30 are formed from separate members, and therefore, even when manufacturing multiple types of date indicators 10 with different designs of letters and numbers written on the date plate 20, the internal gear 30 of the date indicator 10 can have a single common specification regardless of differences in the design of the date plate 20. Therefore, by standardizing the internal gear 30, the date indicator 10 of Embodiment 1 can reduce manufacturing costs and costs required for parts management compared to conventional date indicators in which the display section and gear section are formed from a single member.

[0072] Furthermore, in the date indicator 10 of the first embodiment, the date plate 20 and the internal gear 30 are formed as separate members, so that the design of the date plate 20 can be easily changed.

[0073] In other words, in conventional date wheels, the display section and gear section are integrally formed from a single member, and when the date wheel is assembled into the movement, it is necessary to remove the date wheel from the movement in order to change the display section to a different design, making the process of changing the date wheel design extremely complicated and labor-intensive. Moreover, because a portion of the date wheel is covered by the date wheel retaining plate that is attached to the movement after the date wheel is assembled into the movement, it is also necessary to remove the date wheel retaining plate before removing the date wheel from the movement.

[0074] In contrast to this, with the date indicator 10 of embodiment 1, even when the internal gear 30 of the date indicator 10 is pre-assembled to the movement 100, it is possible to select one date indicator 20 from a plurality of different types of date indicators 20 with different designs without removing the internal gear 30 from the movement 100, and fit that selected date indicator 20 onto the internal gear 30 that is already assembled to the movement 100, thereby assembling an integrated date indicator 10. In this case, the date indicator 20 can be fitted onto the internal gear 30 without removing the date indicator retaining plate 90 of the date indicator 10 either.

[0075] Therefore, with the date wheel 10 of embodiment 1, the design of the date plate 20 can be selected even after the internal gear 30 of the date wheel 10 has been assembled to the movement 100, and the process of changing the design of the date plate 20 without removing the date wheel 10 from the movement 100 can be postponed until the process of combining it with the dial 70, compared to conventional date wheels.

[0076] Furthermore, even after the date wheel 20 has been fitted into the internal gear 30 to form an integrated date wheel 10, the internal gear 30 can be removed by elastically deforming the snap fit 35 of the internal gear 30, thereby ensuring a longer period during which the design of the date wheel 20 can be changed.

[0077] Here, if two designs of dial 70 are available for the finished timepiece 200: one with a date display window 71 at the 3 o'clock position as shown in Fig. 4A, and one with a window 71 at the 6 o'clock position as shown in Fig. 4B, for the dial 70 shown in Fig. 4A, the date numbers formed on the date dial 20 must be oriented correctly at the 3 o'clock position where the window 71 is formed. On the other hand, for the dial 70 shown in Fig. 4B, the date numbers formed on the date dial 20 must be oriented correctly at the 6 o'clock position where the window 71 is formed.

[0078] Therefore, in the assembly process of the date wheel 10 of embodiment 1, when the internal gear 30 is attached to the movement 100 and the movement 100 is combined with a dial to complete the watch, the user can actually see the design of the dial to be combined, check the position of the window 71 formed in that dial, and then select the date wheel 20 that corresponds to the design of the dial.

[0079] As described above, with the date indicator 10 of the first embodiment, with the internal gear 30 attached to the movement 100, the date dial 20 can be flexibly adapted to a variety of designs.

[0080] Furthermore, watch movements may also be traded as movements alone, rather than as finished watches. In such transactions, the party that purchases the movement assembles the finished watch by incorporating the movement into the dial 70 and case of the watch 200. Therefore, the party that purchases the movement can freely choose the design of the watch's dial and case.

[0081] Furthermore, when a watch is equipped with a display wheel such as a date indicator, the seller of the movement will install a blank display wheel on the movement and sell the movement with the display wheel attached. If the buyer of the movement also designs the display wheel themselves, the buyer will temporarily remove the display wheel from the movement, apply the design to the display wheel, and then reattach the display wheel to the movement.

[0082] However, the work of attaching and detaching the display wheel to and from the movement requires precise adjustment of the positional relationship between the drive wheel of the movement and the gear portion of the display wheel. Also, if a display wheel retaining plate (date wheel retaining plate 90 in the first embodiment) that holds the display wheel in the face direction is provided, the display wheel retaining plate must be removed before removing the display wheel. These attachment and detachment operations are significantly more difficult than the work of assembling the movement into the case, and may impose a significant burden of effort on the purchaser of the movement.

[0083] In contrast, the date indicator 10 of embodiment 1 allows the party selling the movement 100 to sell the movement 100 with only the internal gear 30 already assembled. The party who purchases the movement 100 can obtain the movement 100 with the date indicator 10 assembled by the simple task of applying their own design to the date dial 20, which is separate from the movement 100, and then fitting that date dial 20 into the internal gear 30 assembled to the movement 100. Therefore, the date indicator 10 can prevent the party who purchases the movement 100 from having to bear a great deal of effort.

[0084] (date plate holder) Figure 5A is a schematic diagram showing the date plate holding member 80, showing the date plate holding member 80 in the holding position with the screw 84 tightened and fixed, and Figure 5B is a schematic diagram showing the date plate holding member 80 in the retracted position with the screw 84 loosened.

[0085] In the date wheel 10 of embodiment 1, the date plate 20 is fitted into the internal gear 30 by a snap fit 35, thereby fixing the date plate 20 to the internal gear 30. However, in order to reliably prevent the date plate 20 from coming off the internal gear 30 even in the event of a strong impact that exceeds the fitting force of the snap fit 35, a date plate pressing member 80 that presses the date plate 20 in the face direction may be additionally provided, as shown in Figures 5A and 5B.

[0086] The date plate holder 80 is formed into an elongated shape from metal or resin material. As shown in Figure 5A, the base end 81 of the date plate holder 80 is fixed to a date indicator holder plate 90 by a screw 84. When the screw 84 is tightened and fixed to the date indicator holder plate 90, the tip end 82 of the date plate holder 80 is positioned in a pressing position that overlaps with the front surface 20a of the date indicator 20 in a plan view, and as a result, the tip end 82 prevents the date indicator 20 from being displaced in the planar direction.

[0087] As shown in Figure 5B, when the screw 84 is loosened to release the base end 81 of the date plate holder 80 and tilt it radially inward, the tip end 82 moves to a retracted position where it does not overlap the front surface 20a of the date plate 20 in a plan view. When the tip end 82 is in the retracted position, the date plate holder 80 allows the date plate 20 to be displaced in the planar direction. Therefore, in the retracted position, the date plate 20 that is fitted to the internal gear 30 can be removed from the internal gear 30, or the date plate 20 can be fitted to the internal gear 30 when it is not fitted to the internal gear 30.

[0088] After the date dial 20 is fitted into the internal gear 30, the date dial holder 80 is returned to the holding position shown in Figure 5A and the base end 81 is fixed to the date dial holder plate 90 by a screw 84, so that the date dial holder 80 prevents the date dial 20 from being displaced in the axial direction (a direction perpendicular to the surface of the date dial 20 (front surface 20a, back surface 20b)), and prevents the date dial 20 from falling off the internal gear 30 even if an impact force is input.

[0089] Figure 6 is a schematic diagram showing another example of a date plate holder member 180, showing the date plate holder member 180 fixed by fixing means 85. The date plate holder member does not have to be fixed or released by a screw 84, as in the case of the date plate holder member 80 described above. In other words, as shown in Figure 6, the flexible date plate holder member 180 may have its base end portion 181 fixed to the date indicator holder plate 90 by fixing means 85 such as a rivet or welding.

[0090] In a natural state where no external force is acting on the date plate pressing member 180, as shown by the solid line in the figure, the tip portion 182 is positioned in a pressing position where it overlaps with the front surface 20a of the date plate 20 in a plan view, and presses the date plate 20 in the axial direction. On the other hand, when an external force is applied to the tip portion 182 by hand or the like, the date plate pressing member 180 deforms into a bent state as shown by the dashed line while the base end portion 181 remains fixed, and the tip portion 182 moves to a position retracted from the front surface 20a of the date plate 20.

[0091] When the tip 182 of the date plate holder 180 is in a retracted position, the date plate 20 fitted to the internal gear 30 can be removed from the internal gear 30, or when the date plate 20 is not fitted to the internal gear 30, the date plate 20 can be fitted to the internal gear 30.

[0092] (solar cell) FIG. 7 is a cross-sectional view showing a timepiece 200 including a movement 100 equipped with a solar cell 60 on the dial 70 side of the internal gear 30.

[0093] When the movement 100 of embodiment 1 is equipped with a solar cell 60, the solar cell 60 is arranged closer to the dial 70 than the date indicator 10 (on the opposite side of the movement 100), as shown in Figure 7. In this case, it is preferable that the diameter d1 of the inner peripheral edge 20c of the date wheel 20 of the date indicator 10 is larger than the outer diameter d2 of the solar cell 60.

[0094] In this way, the date indicator 10, in which the diameter d1 of the inner peripheral edge 20c of the date dial 20 is formed larger than the outer diameter d2 of the solar cell 60, allows the date dial 20 to pass outside the solar cell 60 without coming into contact with the solar cell 60. Therefore, in a state in which the internal gear 30 and solar cell 60 are assembled to the movement 100, it is possible to fit the date dial 20 into the internal gear 30 from outside the movement 100, or to separate the date dial 20 from the internal gear 30 and remove it outside the movement 100, with the solar cell 60 still attached to the movement 100.

[0095] <Embodiment 2> Figures 8, 9A, and 9B are figures showing the date indicator 110 of another embodiment (embodiment 2) of the display wheel of the present invention, where Figure 8 is an exploded oblique view of the date indicator 110 with the date plate 120 and internal gear 130 separated, viewed from the back side corresponding to Figure 3B, Figure 9A is a plan view showing the back side of the date indicator 110, and Figure 9B is a plan view showing the front side of the date indicator 110.

[0096] 10 is a partially enlarged view showing the details of part E in FIG. 9A, FIG. 11A is a cross-sectional view taken along line FF in FIGS. 9A and 9B, FIG. 11B is a cross-sectional view taken along line GG in FIGS. 9A and 9B, and FIG. 11C is a cross-sectional view taken along line HH in FIGS. 9A and 9B.

[0097] The date wheel 10 of embodiment 1 uses two protrusions 21, 22 on the date plate 20 and a hole 36 and a notch 37 on the internal gear 30 as positioning parts for positioning the date plate 20 and the internal gear 30 circumferentially around the center C0, but the positioning parts are not limited to the combination of these protrusions 21, 22 and the hole 36 and notch 37.

[0098] The date indicator 110 of embodiment 2 shown in Figures 8, 9A, and 9B is formed in a substantially annular plate shape, similar to the date indicator 10 of embodiment 1. The date indicator 110 has a date plate 120 (an example of a display plate) and an internal gear 130 (an example of a gear in a gear member). The date indicator 110 is integrated by fitting or engaging the date plate 120 and internal gear 130, which are formed separately from each other, using a mechanical fitting structure. Before being integrated as the date indicator 110, the date plate 120 and internal gear 130 are separate, as shown in Figure 8.

[0099] (Japanese board) The date dial 120 is basically the same as the date dial 20, but differs in the form of the positioning portion that positions it relative to the internal gear 130. That is, as shown in Figure 8, the date dial 120 has the same configuration as the date dial 20, except that it is equipped with an irregularly shaped protrusion 121 and an abutment portion 122 as positioning portions instead of the two protrusions 21, 22. As shown in Figure 10 as an example, the irregularly shaped protrusion 121 has a rectangular outline that is elongated in a direction perpendicular to the radial direction of the date dial 120, with the two radially inner corners of the outline being chamfered to form sloping shoulders 121b, and the central portion of the part corresponding to the long side of the elongated rectangle between the two shoulders 121b forming an inner tip 121a that protrudes radially inward in a semicircular shape.

[0100] The protrusion 121 is formed to protrude in the thickness direction on the back surface 120b of the date dial 120. The protrusion 121 is formed in an area that overlaps with the outer periphery 32 of the internal gear 130 when fitted with the date dial 120 in a plan view.

[0101] The abutment portion 122 is formed to protrude radially inward from the inner peripheral edge 120c of the date dial 120. The abutment portion 122 is formed at an angle of 180 degrees with the center C0 in between relative to the convex portion 121. Note that the abutment portion 122 may be provided at two locations with the center C0 in between relative to the convex portion 121, for example, at an angle of 120 to 150 degrees and at an angle of 210 to 240 degrees.

[0102] The date wheel 110 is configured such that the abutment portions 122 are provided at two or more locations, one at an angle of more than 90 degrees but less than 180 degrees, and the other at an angle of more than 180 degrees but less than 270 degrees, on either side of the 180 degree angle relative to the protrusion 121, thereby further improving the accuracy of positioning the date wheel 120 relative to the internal gear 130.

[0103] The protruding end face 122a of the abutment portion 122, which is the surface protruding from the inner peripheral edge 120c, is formed so as to abut against the step surface 133 of the internal gear 130 when fitted with the date dial 120, as shown in Figure 9B in a plan view (a surface formed as a step at the boundary between the inner peripheral portion 131 and the outer peripheral portion 132 due to the difference in thickness between the inner peripheral portion 131 and the outer peripheral portion 132 (see Figure 11C)).

[0104] (internal gear) The internal gear 130 is basically the same as the internal gear 30, but the shape of the positioning portion that positions it relative to the date dial 120 is different. That is, as shown in Figure 8, the internal gear 130 has the same configuration as the internal gear 30, except that a tracing portion 136 is formed as a positioning portion instead of the hole 36 and notch 37. Therefore, the internal gear 130 has internal teeth 134 that mesh with the drive teeth of the movement 100, and also has a snap fit 135, which is an example of a fitting structure that mechanically fits the date dial 120 and the internal gear 130, as shown in Figures 9B and 11B.

[0105] The snap fit 135 has the same configuration as the snap fit 35 formed on the internal gear 30. That is, as shown in Figure 11B, the inclined step surface 133a of the snap fit 135 presses the inclined end surface 120d of the inner peripheral edge 120c of the date dial 120 downward in the vertical direction and outward in the radial direction as shown. In this way, the snap fit 135 holds the date dial 120 and the internal gear 130 in a mechanically fitted state.

[0106] The imitation portion 136 is formed on the outer circumferential portion 132 of the internal gear 130. As shown in Figures 9A, 9B, and 10, the imitation portion 136 is formed so as to contact the outer circumferential contour shape of the protrusion 121 of the date dial 120 when it is fitted with the internal gear 130 from the inside (In) in the radial direction.

[0107] When the internal gear 130 and the date dial 120 are fitted together, as shown in Figure 11C, the protruding end face 122a of the abutment portion 122 of the date dial 120 abuts against the step surface 133 of the internal gear 130, and as shown in Figure 11A, the convex portion 121 abuts against the tracing portion 136 from the outside (Out), thereby positioning the date dial 120 radially relative to the internal gear 130.

[0108] At this time, as shown in Figure 10, the inner tip 121a of the convex portion 121 elastically deforms the tracing portion 136 radially inward. When the tracing portion 136 elastically deforms, the distance between the two base ends 138, 138 of the tracing portion 136 becomes shorter. Then, the shoulder portions 121b on both sides of the convex portion 121 come into contact with the respective base ends 138, and the date dial 120 rotates slightly along the circumferential direction R and stops so that it is in a position where both shoulder portions 121b, 121b are in contact with the base ends 138 with an equal load.

[0109] In this way, the date indicator 110 can automatically position the date dial 120 and the internal gear 130 in a predetermined positional relationship around the center C0 by means of the convex portion 121 and abutment portion 122 formed on the date dial 120 and the profiling portion 136 formed on the internal gear 130. Therefore, the convex portion 121, abutment portion 122, and profiling portion 136 are an example of a positioning portion. Then, the date dial 120 and the internal gear 130 are fitted together with a snap fit 135 to form an integrated date indicator 110.

[0110] The date indicator 110 of the second embodiment configured as described above exerts the same action and effect as the date indicator 10 of the first embodiment.

[0111] <Other embodiments> In embodiments 1 and 2, a date wheel 10, 110 having a date plate 20 (an example of a display plate) that displays the numbers of the calendar date is applied as an example of a display wheel according to the present invention, but the display wheel according to the present invention is not limited to the date wheel 10, 110, and may also be a day wheel having a day plate (an example of a display plate) that displays the day of the calendar, a month display wheel having a month plate (an example of a display plate) that displays the month of the calendar, or a city name display wheel having a city name plate (an example of a display plate) that displays the name of the city corresponding to the time indicated by the hands of the clock.

[0112] The display wheel according to the present invention is not limited to having characters written on it, but may have a design. In the present invention, the characters, etc. include designs and are used to refer to anything written or displayed on the display wheel.

[0113] Furthermore, the display wheel of the present invention can be applied with a design that displays the so-called age of the moon, a design of the moon or the sun, or the like, and the display wheel of the present invention can also be applied with a display wheel in which these designs are displayed on a display board (an example of a display board). Specifically, for example, the display wheel of the present invention can be equipped with a display board on which a design is displayed, and a gear member having a central wheel (gear) that meshes with the drive teeth of a timepiece movement and is driven to rotate around its center.

[0114] Here, the gear member has an axis provided along the center of the gear and a hub (a tube for fixing the indicator wheel to the axis) provided at the end of the axis, and the center wheel, axis, and hub are rotatable together around the center. The indicator wheel can be equipped with a positioning part that positions the hub of the gear member and the indicator plate in a predetermined positional relationship, and a mechanical fitting structure that fits the hub of the gear member and the indicator plate together to form a unit.

[0115] In embodiments 1 and 2, as an example of a gear member in a display wheel according to the present invention, an internal gear 30, 130 is applied, which is a gear without a shaft and has internal teeth 34, 134 formed on the radial inner circumference. However, the gear member in a display wheel according to the present invention is not limited to the internal gear 30, 130, and may be an externally toothed gear with a shaft and teeth formed on the radial outer circumference. [Explanation of symbols]

[0116] 10-day indicator (example of indicator) 20 Day board (example of a display board) 30 Internal gear (an example of a gear in gear components) 35 Snap Fit 100 Movement (Example of a watch movement) C0 center

Claims

1. A display wheel that displays multiple characters and rotates, a display board on which the characters etc. are displayed; a gear member having a gear that is driven by meshing with the drive teeth of the timepiece movement, The display wheel includes a positioning portion that positions the display plate and the gear member in a predetermined positional relationship, and a mechanical fitting structure that fits the display plate and the gear member together to form a single unit.

2. 2. The display wheel according to claim 1, wherein said display plate and said gear member are formed of different materials.

3. 2. The display wheel according to claim 1, wherein the positioning portions are two protrusions formed on the display plate and a hole and a notch formed on the gear member.

4. 2. The display wheel according to claim 1, wherein the positioning portion comprises a protrusion formed on the display plate and an abutment portion that abuts against the gear member, and a tracing portion formed on the gear member that contacts the protrusion to position the protrusion at a predetermined position in the circumferential direction.

5. A display wheel as claimed in any one of claims 1 to 4, wherein the display board has the positioning portion on a back surface opposite to the front surface on which the characters etc. are displayed, and has a mark on the front surface that is in a predetermined positional relationship with the positioning portion.

6. 5. A display wheel according to claim 1, wherein the mechanical fitting structure is provided in a plurality of distributed positions around the center of the display wheel in a circumferential direction around the center of the display wheel.

7. 6. The display wheel according to claim 5, wherein a plurality of said mechanical fitting structures are provided in a distributed arrangement surrounding the center of said display wheel along a circumferential direction around the center of said display wheel.

8. A timepiece movement equipped with the display wheel according to claim 1.

9. A timepiece equipped with the display wheel according to claim 1.

Images