HK40035953B - Dial for a universal watch - Google Patents

Description

World time watch dial

Technical Field

This invention relates to horology, and more specifically, to a dial that can be used in a clock with a world time display.

Background Technology

A world time watch can simultaneously display the current time in different time zones around the world. Such a watch typically includes a fixed dial, hour and minute hands that move clockwise above the dial at 12-hour and 1-hour intervals respectively, a 24-hour disc, and a concentric disc marked with the names of cities or global locations representing different time zones. The 24-hour disc is connected to the hour hand via gears, allowing it to rotate counter-clockwise at 24-hour intervals. The time in a particular location is indicated by the divisions on the 24-hour disc facing that location. In most cases, the dial and the city-named disc are separate components. The dial is usually centrally located and integrated with the movement, with the 24-hour and city discs arranged coplanarly around the central dial. This design has a particular drawback: adjusting the upper parts of the movement is required specifically for setting the dial.

Summary of the Invention

One object of the present invention is to provide a dial that does not have the aforementioned disadvantages. This object is achieved by a dial according to the appended claims. The invention also relates to a timepiece, such as a wristwatch, equipped with a dial according to the invention. The dial according to the invention comprises an annular member in the form of an annular plate; a central disc mounted concentrically and substantially coplanarly with respect to the annular member, the diameter of the central disc being smaller than the inner diameter of the annular member to form an annular region between them; and a transparent member covering said annular region. Furthermore, the transparent member is fixed to the disc and the annular member to secure these elements to each other. This dial can be used in timepieces with a world time display and allows for the simple mounting of a 24-hour dial on the movement below the dial, and the markings on the 24-hour dial are visible through the transparent member.

Attached Figure Description

The specific features and advantages of the present invention will appear in the following description, with reference to the accompanying drawings and by way of non-limiting examples, of preferred embodiments.

Figure 1 shows a front view of the dial according to an advantageous embodiment of the present invention.

Figure 2 shows a cross-sectional view along section A-A shown in Figure 1.

Figure 3 shows an exploded view of the components of the dial shown in Figures 1 and 2.

Figure 4 shows a watch with the dial shown in Figure 1.

Detailed Implementation

The dial 1 shown in Figures 1 and 2 comprises three interlocking parts to form a single integral component. The dial can be used in a wristwatch. The dial 1 includes a flat annular element 2, preferably made of metal, which is in the form of an annular plate with an outer diameter D1 and an inner diameter D2. In the embodiment shown in the figures, the annular element 2 has 12 indicators 3 (see Figure 2) fixed to the upper surface of the annular element 2 by mounting feet 4. "Upper surface" here refers to the surface that will be positioned facing the watch crystal, and "lower surface" refers to the opposite surface. The positions of the indicators 3 indicate the hour from 1 to 12. The annular element 2 also bears the names of twenty-four cities, regularly distributed around the edge of the annular element 2, corresponding to the twenty-four time zones of the world. These names are etched on the upper surface of the annular element 2 and the surface of an additional annular element 5, which has a surface inclined relative to the plane of the annular element 2. The additional annular element is fixed to the upper surface of the annular element 2 by mounting feet 6.

In the specific case shown in Figure 1, the annular component 2 also includes an opening 12 at the 6 o'clock position for displaying the date. The annular component 2 is made of an opaque material, such as a metal alloy like CuZn33. A central disc 7, preferably a metal disc, is mounted concentrically with respect to the annular component 2 and substantially on the same plane as the annular component 2. This disc is also made of an opaque material, such as titanium, and includes a central hole 8 through which the pivots carrying the hour and minute hands of the watch pass. The diameter D3 of the central disc 7 is smaller than the inner diameter D2 of the annular component 2, leaving a visible annular region 9 between the disc 7 and the annular component 2. This annular region 9 is covered by a component 10 made of a transparent material, such as polymethyl methacrylate (PMMA) or sapphire.

In the specific case shown in the accompanying drawings, the transparent component 10 also takes the form of a flat annular piece and has a central opening 11 (FIG. 3) concentrically positioned relative to the central disc 7. The opening 11 is sized such that the transparent component 10 covers the annular portion 15 located on the outer periphery of the lower surface of the disc 7. On the radially opposite side of the opening 11, the transparent component 10 covers the annular portion 16, which is on the inner periphery of the lower surface of the annular component 2. The transparent component 10 is joined to the surface portions 15 and 16 to hold the annular component 2 and the disc 7 fixed to each other. As can be seen from the plan view of FIG. 1, the dial 1 thus includes an opaque annular component 2, an opaque central disc 7, and an annular aperture between the disc 7 and the annular component 2.

The exploded view of Figure 3 reveals the specific features of this embodiment. It can be seen that the central disk 7 has an annular portion 17 on its lower surface, which extends in a protruding manner relative to the portion 15 covered by the transparent member 10. The diameter of the protruding portion 17 corresponds to the diameter of the opening 11, thereby allowing the transparent member 10 to be positioned around the protruding portion 17. Furthermore, the protruding portion 17 has a radial protrusion 18 configured to engage in a radial recess 19 arranged in the inner edge 20 of the transparent member 10, such that the transparent member 10 can be fitted onto the disk 7 only at a specific angular position relative to the disk 7.

It can also be seen that the outer edge of the transparent component 10 includes three straight portions 25 arranged at equal angular distances around the periphery of the component 10, while the remaining portion of the edge includes three curved portions 26, which are arcs. The annular portion 16 of the ring 2 to be covered by the transparent component 10 is recessed relative to the rear surface of the ring 2. The annular portion 16 is also provided with complementary straight portions 25' and curved portions 26', which correspond to the straight portions 25 and curved portions 26 of the transparent component 10, thereby allowing the transparent component 10 to be positioned inside the recessed portion 16 by aligning the straight portions 25, 25' and the curved portions 26, 26'. In this embodiment, the lower surface of the ring 2 further includes a recessed region 27 located on the outer periphery of the portion 16, and is provided with a threaded hole 28 disposed at the bottom of the region 27. The hole 28 is configured to receive a mounting screw 29, which is designed to attach the transparent component 10 to the ring 2 or participate in the attachment of the transparent component 10 to the ring 2. Attachment is achieved by mounting the head of the screw 29, which is fitted into the recessed area 27. When the screw 29 is tightened, the head extends over the edge of the component 10 to attach the component 10 to the annular part 2.

The assembly of the dial 1 shown in the figure is preferably performed in two steps. First, after applying adhesive to at least one contact surface, the transparent component 10 is assembled onto the central disc 7 by aligning the protrusions 18 and recesses 19, and by placing the component 10 around the protrusion 17 and contacting it with the surface portion 15. The adhesive that can be used for the titanium disc 7 and the polymethyl methacrylate (PMMA) transparent component 10 is APM Technica Epsilon 2103 adhesive. Then, the assembly formed by the component 10 and the disc 7 is secured to the recessed surface portion 16 of the annular component 2 by applying another adhesive to at least one of the contact surfaces of the transparent component 10 and the contact surfaces of the portion 16 of the annular component 2. Next, preferably, after applying adhesive to the surface of the recessed area 27 where the screw head will be received, the mounting screw 29 is tightened into the threaded hole 28.

The adhesive used between the transparent component 10 and the annular component 2 can be the same type of adhesive used between component 10 and the central disc 7. Alternatively, the adhesive used between the transparent component 10 and the annular component 2 can be weaker than the adhesive used between component 10 and the disc 7. A “weaker” adhesive means that the adhesive provides lower adhesion when the assembly is subjected to a defined impact.

According to yet another embodiment, the transparent component 10 is not bonded to the annular component 2, but is connected to the annular component 2 only by mounting screws 29.

According to another embodiment, the mounting screw 29 is omitted, and the transparent component 10 is bonded to the disc 7 and the annular component 2. In this latter embodiment, the adhesive used between the transparent component 10 and the annular component 2 may be as strong as, or weaker than, the adhesive used between the component 10 and the disc 7.

In embodiments where the adhesive used between the transparent component 10 and the annular component 2 is weaker than that used between the component 10 and the disc 7, or in embodiments where the transparent component 10 is attached to the annular component 2 solely by mounting screws 29, the increased deformability of the transparent component 10 compared to the annular component 2 provides the advantage of improved shock resistance of the dial. In particular, dome-shaped deformation of the dial (“umbrella effect”) that could lead to loosening of the hands is limited upon impact.

Figure 4 shows a watch equipped with the aforementioned dial. The watch has hour and minute hands 30 that move above the dial to indicate the time and are driven by a watch movement (not shown) in a conventional manner. The watch also has a circular 24-hour disc 32, also driven by the movement that moves below the dial 1. The 24-hour disc 32 has twenty-four regularly distributed markings on its surface. These markings are aligned with the annular area between the central disc 7 and the annular element 2, and are thus visible through an aperture formed by the transparent element 10. The 24-hour disc 32 is typically driven and calibrated simultaneously with the hour and minute hands by a known mechanism. The watch also includes a circular date disc aligned with the aperture 12, also driven in a known manner. The central disc 7 can also be decorated, for example, by etching. Typically, the central disc 7, made of, for example, titanium, can be decorated using an ultrashort pulse laser (typically a femtosecond laser), which allows nanostructures to be engraved on the surface of the disc, selectively reflecting visible light of specific wavelengths, thus enabling the production of iridescent patterns.

Those skilled in the art will understand that variations of certain features of the dial described above are within the scope of this invention. The transparent component 10 may be in the form of a solid disc, rather than an annular shape. Instead of adhesives and mounting screws, or other methods of connection besides adhesives and mounting screws, the transparent component 10 may be secured to the disc 7 and/or the annular component 2. The transparent component 10 may be secured to the upper surface of the annular component 2 and/or the disc 7, rather than the lower surface.

Claims (15)

1. A dial (1) for a clock, the dial comprising: - A flat, ring-shaped component (2) made of opaque material, the ring having an outer diameter (D1) and an inner diameter (D2), and an upper surface and a lower surface. - A central disk (7) made of opaque material, the diameter (D3) of which is smaller than the inner diameter (D2) of the annular member (2), the central disk being concentrically positioned relative to the annular member (2) and substantially coplanar with the annular member (2), such that an annular region (9) is formed between the central disk (7) and the annular member (2), the central disk (7) having an upper surface and a lower surface oriented in the same manner as the upper and lower surfaces of the flat annular member (2), respectively. - A transparent component (10) made of transparent material, the transparent component covering the annular region (9) and fixed to the central disk (7) and the annular member (2) to connect the annular member (2) and the central disk (7) together, while forming an annular opening between the central disk (7) and the annular member (2), wherein the transparent component (10) covers at least one surface portion (15) of the upper or lower surface of the central disk (7), wherein the transparent component (10) includes a central opening (11) concentrically positioned relative to the central disk (7), the central disk (7) including a protrusion (17) surrounded by the surface portion (15), the protrusion (17) being sized such that the central opening (11) is positioned around the protrusion (17). 2. The dial (1) according to claim 1, characterized in that the transparent component (10) is fixed to the central disc (7) by combining the transparent component (10) to the surface portion (15). 3. The dial (1) according to claim 1, characterized in that the surface portion (15) of the central disk (7) covered by the transparent component (10) is an annular portion located on the outer periphery of the upper or lower surface of the central disk (7). 4. The dial (1) according to claim 3, characterized in that the transparent component (10) has a flat annular shape, and the size of the central opening is designed such that the transparent component (10) covers the annular portion located on the outer periphery of the upper or lower surface of the central disk (7). 5. The dial (1) according to claim 1, characterized in that the central opening (11) and the protrusion (17) are respectively provided with a radial recess (19) and a radial protrusion (18), or are respectively provided with a radial protrusion and a radial recess, the radial protrusion (18) being configured to engage in the radial recess (19) to allow the transparent component (10) to be assembled to the central disk (7) only at an angular position relative to the central disk (7). 6. The dial (1) according to any one of the preceding claims, characterized in that the transparent component (10) covers at least one surface portion (16) of the upper or lower surface of the annular component (2), and wherein the transparent component (10) is fixed to the annular component (2) by bonding and/or screwing the transparent component (10) to the surface portion (16) of the annular component (2). 7. The dial (1) according to claim 6, characterized in that the surface portion (16) of the annular member (2) covered by the transparent component (10) is an annular portion located on the inner periphery of the surface of the annular member (2). 8. The dial (1) according to claim 7, wherein the annular portion of the annular member (2) is recessed relative to the rest of the surface of the annular member (2). 9. The dial (1) according to claim 7 or 8, characterized in that the transparent component (10) is fixed to the annular component (2) by at least a plurality of mounting screws (29), the mounting screws including screw heads extending above the outer edge of the transparent component (10). 10. The dial (1) according to claim 1 or 2, characterized in that: - The transparent component (10) is fixed to the central disk (7) by a first adhesive. -The transparent component (10) is fixed to the annular component (2) by at least a second adhesive. - The second adhesive is weaker than the first adhesive. 11. The dial (1) according to claim 1 or 2, characterized in that: - The transparent component (10) is fixed to the central disk (7) by a first adhesive. - The transparent component (10) is fixed to the annular component by screws without the use of adhesive. 12. The dial (1) according to claim 1 or 2, characterized in that the annular element (2) includes on its upper surface a plurality of names representing global locations of world time zones. 13. A dial (1) for a clock, the dial comprising: - A flat, ring-shaped component (2) made of opaque material, the ring having an outer diameter (D1) and an inner diameter (D2), and an upper surface and a lower surface. - A central disk (7) made of opaque material, the diameter (D3) of which is smaller than the inner diameter (D2) of the annular member (2), the central disk being concentrically positioned relative to the annular member (2) and substantially coplanar with the annular member (2), such that an annular region (9) is formed between the central disk (7) and the annular member (2), the central disk (7) having an upper surface and a lower surface oriented in the same manner as the upper and lower surfaces of the flat annular member (2), respectively. - A transparent component (10) made of transparent material, the transparent component covering the annular region (9) and fixed to the central disk (7) and the annular member (2) to connect the annular member (2) and the central disk (7) together, while forming an annular opening between the central disk (7) and the annular member (2), wherein the transparent component (10) covers at least one surface portion (15) of the upper or lower surface of the central disk (7), wherein the outer edge of the transparent component (10) has a geometrical portion (25, 26) that allows the transparent component (10) to be angularly aligned with the annular member (2), and wherein the annular portion of the annular member (2) includes an alignment portion (25', 26') corresponding to the geometrical portion (25, 26) on the outer edge of the transparent component (10). 14. A clock including the dial (1) according to any one of the preceding claims. 15. The clock according to claim 14, characterized in that the dial (1) includes a plurality of names representing global locations of world time zones on the upper surface of the annular member (2), and wherein the clock includes a 24-hour disc (32) below the dial (1) to mark world time by a plurality of marks distributed on the 24-hour disc, and wherein the marks are aligned with an annular region (9) between the central disc (7) of the dial and the annular member (2).