Stock material or miscellaneous articles – Structurally defined web or sheet – Including variation in thickness
Reexamination Certificate
2001-10-18
2004-06-22
Loney, Donald J. (Department: 1772)
Stock material or miscellaneous articles
Structurally defined web or sheet
Including variation in thickness
C428S142000, C428S161000, C428S163000, C428S167000, C428S187000, C428S542200, CD10S123000
Reexamination Certificate
active
06753068
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a decorative plate having superior appearance by having a decorative groove carved thereon, a method of manufacturing the same, and a decorative article and timepiece using the decorative plate.
2. Description of the Related Art
Conventionally, a dial plate used for a wristwatch has been produced with a thin plate material of 0.4 mm thickness, such as a plate made from brass, in order to minimize the overall thickness of the wristwatch.
Specifically, in order to produce the dial plate, after the thin sheet-shape plate material is formed in a shape corresponding to the design of the wristwatch body and a center hole for inserting a driving shaft for driving the pointer is formed at the center thereof, a leg for securing to a movement is attached by welding etc.
Subsequently, the surface of such dial plate is ground and polished, and, after a decorative pattern such as radial pattern, moiré pattern, matrix pattern or spiral pattern is formed thereon by press stamping etc., the dial plate is plated and is colored by coating a paint including a pigment on the plating as necessary, which is further finished with clear coating.
And finally, a time and minute graduation for indicating time is printed thereon and a metal abbreviated character as a separate body is bonded to finish the dial plate.
In the spiral pattern, among the above decorative patterns, a pattern having a spiral groove is formed by moving a cutting edge, such as cemented carbide tool provided on a lathe, in a diametric direction of a rotary table while rotating the dial plate fixed to the rotary table to carve a groove of approximately 0.012 to 0.05 mm pitch and approximately 0.05 mm depth in spiral.
The pattern formed by a spiral groove has an appearance like a phonograph record without an uneven pitch and, since the groove works as a diffraction grating, reflected light varies in attractive rainbow colors according to the visual angle.
Such pattern formed by a spiral groove can be used not only for the dial plate of a wristwatch, but also as a decorative plate of knob of furniture or of an electric appliance, or as a decorative plate of accessories such as a necklace, cuff links or necktie pin.
However, such conventional decorative plate is planar and lacks a three-dimensional effect since it is produced from a thin plate, even when such pattern formed by spiral groove is provided, so that depth and luxurious touch cannot be afforded.
The three-dimensional effect can be created by forming the decorative plate in convex and concave lens or in Fresnel lens-shape. However, when the decorative plate is formed in a lens-shape, the thickness thereof may increase, thus making it difficult to be produced from a thin plate material.
Especially, a decorative plate used for a dial plate of wristwatch is extremely difficult to produce when the thickness of the dial plate is increased due to restrictions in design and production of the wristwatch.
Alternatively, a thick plate material may be three-dimensionally shaped using a NC carving machine etc. However, in this case, the thickness of the decorative plate and production cost thereof can increase greatly.
OBJECTS OF THE INVENTION
An object of the present invention is to provide a decorative plate having a three-dimensional effect, depth and luxurious touch even when produced from a thin plate, a method of manufacturing thereof, and a decorative article and timepiece using the decorative plate.
SUMMARY OF THE INVENTION
A first aspect of the present invention is a decorative plate including: a decorative portion carved with a decorative groove extending in spiral from inside toward outside of the decorative plate, the decorative groove being formed in a cross section of V-shape and including a non-equilateral portion where a slant angle of one of a pair of slanted sides forming the V-shape is different from a slant angle of the other slanted side.
According to the above first aspect of the present invention, by making the slant angle of an inner slanted side forming the V-shape of the decorative groove gentler than an outer slanted side at an inner part of the spiral, since the action of light reflected on the flat surface of the dial plate macroscopically becomes similar to the light reflected on a bulging surface, the central portion of the dial plate appears to be bulging. Accordingly, the decorative portion can achieve a three-dimensional effect even when the dial plate is made of thin plate.
On the other hand, by making the slant angle of an inner slanted side forming the V-shape of the decorative groove steeper than an outer slanted side, since the action of light reflected on the flat surface of the dial plate macroscopically becomes similar to the light reflected on an indented surface, the decorative portion can appear indented, thereby also achieving a three-dimensional effect even when the dial plate is made of thin plate.
The material of the decorative plate may be metal such as copper, bronze, German silver and aluminum, synthetic resin, glass, shell such as mother of pearl black and mother of pearl and precious stone, and composite material made by attaching thin plates of the above materials.
In the above decorative plate, the slant angles of the pair of slanted sides of the decorative groove may preferably vary gradually from the inner part of the spiral toward the outer part to be equal at the outer part.
Accordingly, when the slant angle of the V-shaped slanted sides vary greatly, the surface can be shown in steeply inclined manner and the slant angle is shown gentler as the slant angles of the V-shaped slanted sides become closer to each other.
For instance, when a decorative groove where the slant angle of the inner slanted side of the spiral is gentler than the outer slanted side and the slant angles of the slanted sides become gradually equalized from the inner part of the outer part of the spiral is provided on the disk-shaped material plate, a decorative plate having apparently greatly bulging central portion and flat peripheral portion as shown in
FIG. 1
can be obtained.
On the other hand, when a decorative groove where the slant angle of the inner slanted side of the spiral is steeper than the outer slanted side and the slant angles of the slanted sides become gradually equalized from the inner part of the outer part of the spiral is provided on the disk-shaped material plate, a decorative plate having apparently greatly dented central portion and flat peripheral portion as shown in
FIG. 2
can be obtained.
By forming such decorative groove, even when the decorative plate is made of thin plate, an apparent greater thickness relative to actual thickness thereof can be exhibited even when the decorative plate is made of thin plate.
In the above decorative plate, a decorative plating layer may preferably be provided at least on the decorative portion and the plating step for forming the decorative plating layer on the decorative portion may preferably be conducted after the carving step for carving the decorative groove.
By thus forming the decorative plating layer on the decorative portion, even when the decorative plate is made of synthetic resin, a three-dimensional effect can be achieved on the decorative plate by providing the decorative portion on the decorative plate.
When a precious metal layer having superior corrosion resistance is used as the decorative plating layer, even when an easily-carved metal of inferior corrosion resistance such as brass is used as the material of the decorative plate, superior corrosion resistance can be applied to the decorative plate and beautiful appearance can be maintained for a long time and the decorative groove can be easily carved on the decorative plate.
The decorative plating layer may be formed by silver, gold, rhodium and nickel.
In the decorative plate, a colored coating layer including a pigment may preferably be provided at least on the decorative portion and the coating step for forming the colored coating lay
Kasahara Sachio
Nakamura Yuichi
Loney Donald J.
Seiko Epson Corporation
Watson Mark P.
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