JPH06109866A - Cover glass for timepiece and manufacture thereof - Google Patents

Abstract

PURPOSE:To make it possible to constitute a plurality of surfaces, characters, numbers and patterns in the solid state on the inner surface of cover glass and to expand the spreading of commodities by forming the solid shape, which is constituted on the inner surface of the cover glass for a time piece with a metal mold. CONSTITUTION:A metal mold 4 for a cover glass 1 for a timepiece, wherein many surfaces are cut, is constituted of a negative form 5, a positive form 6 and an outer ring 7. A round white glass plate 8 having the thickness of about 1.5mm and the outer diameter of 20mm is inserted between the positive form 6 and the negative form 5. After the glass is set in the molding device, the pressure of about 200kg/cm<2> is applied at 600 deg.C in inactive-gas atmosphere. The glass is held about 60 seconds in the intact state. Then, the cover glass 1 having multiple-surface cut parts 3 on the inner surface is formed. As the mold material, sintered hard alloy is used. For the machining of the surface of the positive form 6, a diamond cup wheel is used. A dividing board with an angle is attached to the NC milling machine of the machining apparatus. Thus, 24 surfaces can be machined.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cover glass in which a three-dimensional shape composed of a plurality of surfaces is formed on the inner surface of a watch cover glass and a method for manufacturing the cover glass.

[0002]

2. Description of the Related Art A watch cover glass is originally joined to a watch case to protect a dial and hour, minute and second hands for displaying time. That is, it functions as protection of the time display mechanism. In this way, the cover glass for watches, which has been used as a part of functional parts in the past, is cut into a square surface or a brilliant look that mimics a diamond to give it a decorative purpose. To improve the total image of the watch.

To cut the surface of the cover glass, a diamond grindstone 14 for grinding and a grindstone 15 for finish polishing are attached to a Zaraz-type NC grinder 12 shown in FIG.
A jig and an attachment 18 which are divided at an arbitrary angle called a dividing plate 17 are attached to the. With this dividing plate, an arbitrary machined surface and the number of machined surfaces can be determined. The cover glass 13 to be processed is fixed by an attachment attached to the polishing table, and the dividing plate is attached to this attachment. First, the cover glass 13 fixed to the attachment is first ground at the grinding position 19 by the diamond grinding wheel 1 for grinding.
Grinding is performed by 4. For example, if there are twelve surfaces to be machined, a twelve-divided dividing plate is attached to the attachment 18, and an appropriate amount of grinding is sent to cut twelve divided surfaces. When the grinding process is completed, the finishing grinding wheel 15 performs a mirror-finishing process for turning the ground divided surface into a mirror surface at the finish polishing position 20, and when the mirror surface is obtained on the entire divided surface, the mirror-finishing is finished. A cover glass for a watch having a cut surface on the surface of the cover glass completes 1A of FIG. As shown in FIG. 6, the cut surface 3A of the processed cover glass can be processed only on the surface of the cover glass due to the structure of the Zalatsu NC polishing machine 12. Organic glass materials are rarely used as materials for conventional cover glasses for watches, but most of the face-cut cover glasses are inorganic glass materials. The hardness of this inorganic glass material is Hv900 in micro-Vickers, and the flatness of the diamond grindstone for grinding 14 and the diamond grindstone for finish polishing 15 is impaired as the processing progresses, and a smooth cut surface cannot be obtained. The truing of the grindstone is performed with the number of processed pieces of 150 to 200 as a guide.
By truing the grindstone, the grindstone / polishing grindstone is carefully set and the flatness is corrected. And this truing is to maintain the improvement of processing rate and the improvement of surface roughness,
It is essential for grinding and polishing.

[0004]

As described above, in the prior art, as the number of machining increases, a smooth cut surface cannot be obtained due to the abrasion of the grindstone surface, and thus truing must be performed, and the truing requires correction. In addition to reducing time, the cut surface of the cover glass is limited to the entire surface, so the edges and vertices of the cut surface are lost while carrying the watch, and the aesthetic appearance at the time of purchase is impaired. Therefore, it has been a problem to form a three-dimensional shape on the inner surface of the cover glass with a plurality of surfaces and also to form letters, numbers, and patterns in the same manner.

Therefore, the present invention is intended to solve such a problem, and an object thereof is to manufacture a cover glass for a watch having a plurality of planes, letters, numbers and patterns in a three-dimensional shape on the inner surface. Is what makes it possible.

[0006]

[Means for Solving the Problems] A means for solving the above problems is to mold the three-dimensional shape of the inner surface by a mold.

[0007]

【Example】

(Embodiment 1) FIG. 1 is a sectional view of a multi-sided cut timepiece cover glass 1 in which twenty-four cut surfaces are three-dimensionally formed on the inner surface of the timepiece cover glass in the first embodiment of the present invention. In the figure, a cover glass 1 for a multi-sided cut timepiece is formed by molding a surface slope 2 and an inner multi-sided cut 3. FIG. 2 is a plan view of a multi-sided cut timepiece cover glass having 24 cut surfaces on the inner surface of the timepiece cover glass according to the first embodiment of the present invention. As shown in FIG. 2, the molded cover glass has a beautiful cut surface, and the surface reflection of light has a large effect. In addition, there is a concern that the cut surface that has been conventionally provided on the surface may damage the aesthetics at the time of purchase, such as scratches and chipping of edges, but according to this embodiment, the cut is configured on the inner surface, so there is no concern about scratches or chipping. Is gone.

(Embodiment 2) FIG. 3 is a sectional view showing the structure of a cover glass molding die 4 for a multi-sided cut timepiece according to a second embodiment of the present invention. The mold is composed of a female mold 5, a male mold 6, and an outer ring 7, and a molding machine in which a round white glass plate 8 having a thickness of 1.5 mm and an outer diameter of 20 mm is inserted between the male mold and the female mold. After that, a pressure of 200 Kg / cm ² is applied at 600 ° C. in an inert gas atmosphere, and the pressure is maintained for 60 seconds to complete the molding. In this way, the cover glass 1 for a multi-sided cut timepiece having the cut surface on the inner surface of the cover glass could be manufactured. In this way, it is possible to manufacture the cover glass having the cut surface on the inner surface because the male die 6 of FIG. 3 is processed to form the cut surface. Cemented carbide was used as the die material, and a diamond cup wheel was used for processing the cut surface of the male die 6. The processing machine was an NC milling machine equipped with an angled dividing machine. With this angled dividing plate, it is possible to machine twenty-four surfaces, and the male die 6 having the cut surface shown in FIG. 3 is completed. By molding using this male mold, it becomes possible to form the cut surface, which was conventionally possible only on the front side as the cover glass, in the inner surface according to this embodiment.

(Embodiment 3) FIG. 4 is a plan view of a dial plate type cover glass 9 for a timepiece, in which letters and numbers are three-dimensionally molded on the inner surface of a watch cover glass in a third embodiment of the present invention. Numbers were displayed at four locations including 12:00, and the remaining eight locations were displayed as patterns. First, a male die of a forming die was engraved with a numeral 10 and a pattern 11 by an die-sinking electric discharge machine to prepare a die. The molding conditions were the same as in Example 1 to produce the dial watch glass cover glass 9 shown in FIG. Since all the numbers and patterns are molded on the inner surface side, the surface side was completely flat and there was no protrusion, and a clean cover glass could be obtained.

Example 4 In Example 2, a cover glass for a multi-sided cut timepiece was molded with white plate glass as a molding material. In Example 4, an organic glass material was used as a molding material. Acrylic was used as the organic glass material. As a result of molding at a molding temperature of 120 degrees Celsius, a cover glass for a multifaceted timepiece similar to that shown in FIG. 1 could be manufactured.

In this embodiment, white glass was used as the inorganic glass as the molding material, but not limited to optical glass such as BK-7, the organic glass material is not particularly limited to acrylic.

[0012]

As described above, according to the present invention, the cover glass for a watch, which cannot be formed on the inner surface of the cover glass for a watch according to the present invention, is limited to the front side. It becomes possible to form multiple three-dimensional shapes on the inner surface of glass, and it becomes possible to manufacture cover glass for multi-sided cut watches having a cut surface on the inner surface and cover glass for dial-shaped timepieces. It enables product development by expanding the design.

[Brief description of drawings]

FIG. 1 is a sectional view of a cover glass for a multi-sided cut timepiece according to a first embodiment of the present invention.

FIG. 2 is a plan view of a cover glass for a multi-sided cut timepiece according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a cover glass molding die for a multi-sided cut timepiece according to a second embodiment of the present invention.

FIG. 4 is a plan view of a cover glass for a dial plate timepiece according to a third embodiment of the present invention.

FIG. 5 is a structural diagram of a Zalatsu type NC polishing machine.

FIG. 6 is a cross-sectional view of a conventional cover glass for front surface side cut timepiece.

[Explanation of symbols]

 1 Multi-faced cut watch cover glass 2 Surface beveled surface 3 3A Multi-faced cut part 4 Molding die 5 Female 6 Male 7 Outer ring 8 White plate glass 9 Dial plate type watch cover glass 10 Number 11 Pattern 12 Saraz NC polishing Machine 13 Cover glass 14 Grinding grindstone 15 Finishing grindstone 16 Grinding stand 17 Dividing board 18 Attachment 19 Grinding position 20 Finishing position

Claims (5)

[Claims] 1. A cover glass for a watch, which is joined to a watch case and protects a time display mechanism from the outside,
A cover glass for a watch characterized in that a three-dimensional shape composed of a plurality of surfaces is formed on at least the inner surface of the outer surface and the inner surface of the cover glass for a watch. 2. The cover glass for a timepiece according to claim 1, wherein the three-dimensional shape of the inner surface is formed by a mold. 3. The method for producing a cover glass for a timepiece according to claim 1, wherein the three-dimensional shape of the inner surface is molded by a mold. 4. The cover glass for a timepiece according to claim 1, wherein the three-dimensional shape formed by the plurality of surfaces formed on the inner surface is a letter, a number, or a pattern. 5. The timepiece cover glass according to claim 1, wherein the timepiece cover glass is an organic glass material or an inorganic glass material.