GB2062907A

GB2062907A - Decorative front plate for timepiece

Info

Publication number: GB2062907A
Application number: GB7938825A
Authority: GB
Original assignee: Citizen Watch Co Ltd
Current assignee: Citizen Watch Co Ltd
Priority date: 1979-11-09
Filing date: 1979-11-09
Publication date: 1981-05-28
Also published as: HK28886A; GB2062907B

Abstract

A decorative front plate for a timepiece comprises a surface layer (18) of soft material, an intermediate layer (20) of hard material and a backing layer (22) of soft material. The material are laminated in order to form the front plate, which may be a dial or a masking plate for a digital watch. The arrangement is stated to facilitate the production of a very thin front plate which readily accepts decoration while being resistant to distortion as a result of stamping or of the attachment of hour chapters or rear fixing legs. <IMAGE>

Description

SPECIFICATION Decorative front plate for timepiece This invention relates to a dial plate and masking plate for a timepiece, particularly a dial plate and masking plate fabricated by using three layers of clad materials, namely a soft metal layer, hard metal layer and soft metal layer clad in the order mentioned.

In the following, the term "dial plate" has the usual meaning in the art, of a timepiece dial plate having a central aperture through which a shaft for driving time indicating hands protrudes and a plurality of time indication markers on the upper surface to indicate the hours, etc of time.

The term "masking plate" refers to the uppermost plate beneath the watch glass of a digital display type of timepiece. This plate has aperture provided thereon through which the digital display is visible, while other portions of the timepiece module are masked off by the masking plate. The term "decorative front plate" as used in the following description and in the appended claims has the meaning of a collective term designating both dial plates and masking plates produced according to the present invention.

It has been conventional practice to make use of such metals as brass, nickel silver, copper or aluminum to fabricate dials used in timepieces. However, these metals cannot provide the required external appearance and functional quality when manufacturing thin dial plates having an overall thickness of less than 300 y. This is because the attractiveness of the dial plate is diminished by protuberances formed on its top surface during a welding process for attaching legs to the dial plate, and because satisfactory flatness cannot be obtained due to bending which is caused during a press-punching step.Attempts have been made to eliminate three problems by making use of hard metal materials but these materials do not lend themselves to mass production because of severe bending which occurs when small holes are punched in the dial plates in order to attach the legs of brandmark plates and time numerals. Problems associated with the welding of legs also make practical application difficult since the required strength cannot be obtained. Moreover, dial plate and masking plate made of these hard metals cannot fully satisfy the requirement for finished products that exhibit rich and varied decorative patterns but which are also extremely thin and becoming thinner in order to contribute further to the progress which has recently been made in reducing timepiece thickness.

According to the present invention, there is provided a decorative front plate for a timepiece, comprising: a surface layer composed of a soft material and having an upper surface; an intermediate layer composed of a hard material and attached to a lower surface of said surface layer for reinforcing said decorative front plate; and a backing layer composed of a soft material and attached to a lower surface of said intermediate layer.

In the attached drawings: Figures 1A, 1B, 2A and 2B are plan views of a dial plate and masking plate, respectively, in accordance with the present invention; Figure 3 is a partial cross-sectional view of the decorative front plate shown in Figs. 1 A, 1 B, 2A and 2B; Figure 4 is a schematic view of a conventional patterning process for producing a radiating pattern; Figure 5 is a schematic view of a conventional stamp-patterning process; Figure 6 is a partial cross-sectional view of a half-completed dial plate which has been subjected to patterning, pressing and leg-welding steps; Figure 7 is a cross-sectional view of a leg-welding portion of a dial plate having a thickness of less than 30 iL and constituting the conventional dial plate material with a leg welded thereto;; Figure 8 is a cross-sectional view of a thin dial plate composed of the clad metals in accordance with the present invention and shown after having been subjected to patterning, pressing and leg-welding steps; Figure 9 is a cross-sectional view of a thin dial plate composed of the conventional dial plate material and shown after having been subjected to steps from patterning to attachment of the legs; Figure 10 is a partial cross-sectional view of a completed dial plate manufactured using a clad material I of Table I; Figure 11 is a cross-sectional view of a blank of a thin dial plate manufactured using a clad material II of Table I but shown prior to anodizing and coloring treatments; and Figure 12 is a partial cross-sectional view of a dial plate manufactured using a clad material Ill of Table II.

Figs. 1 A, 1 B, 2A and 2B are full plan views of dial plates and masking plates in accordance with the present invention. Each of dial plates 10, 1 2 and masking plates 14, 1 6 comprises three layers which include soft materials and a hard material. The dial plate 10 of Fig. 1A and the masking plate 14 of Fig. 2A are textured or patterned by the process shown in Fig. 4, while the dial plate 1 2 of Fig. 1 B and the masking plate 1 6 of Fig. 2B are textured or patterned by the process illustrated in Fig. 5.

Referring now to Fig. 3, a partial cross-sectional view of clad materials constituting the dial plates and masking plates is shown. A surface layer is composed of a soft metal that can be readily patterned. An intermediate layer 20 is composed of a hard metal which has the effect of preventing the formation of protuberances on the surface portion of the decorative front plate when welding legs as well as preventing bending which occurs during press-punching. A backing layer 22 which is composed of a soft metal and is effective in enhancing the strength of attached legs at the time of leg-welding. Thus, the surface layer 1 8 and the backing layer 22 which are composed of a soft metal, and the intermediate layer 20 is composed of a hard metal.

Accordingly, exquisite decorative front plate can be manufactured by easy art.

Fig. 4 shows a schematic view of a patterning process for producing a radiating pattern, and is well known in the art as a method of applying patterns to a dial plate. Numeral 24 indicates a patterning brush that rotates in a direction of arrow 26. Numeral 28 indicates a decorative front plate blank which is supported by a work table 30. The work table 30 rotates in a direction of arrow 32. A surface of the blank 28 is patterned by the patterning brush 24 being held in contact with the blank 28.

Fig. 5 shows a schematic view of a patterning process in which a continuous strip is stamped.

A patterning machine 34 is shown as comprising an upper movable support 36 provided at its bottom end with an upper die 38 formed with a predetermined surface pattern, and a lower support 44 having its upper end provided with a lower die 42. A continuous strip or blank 40 composed of the three clad layers of the hard and soft metals is disposed between the upper and lower dies 40 and 42 and, thereafter, the upper die 38 is lowered relative to the blank 40 to perform patterning step.

Fig. 6 shows a partial cross-sectional view of a half-completed dial plate which has been subjected to patterning, pressing and a leg-welding step. The blank 40 is then stamped to form a decorative front plate as shown in Figs. 1A and 1 B. After stamping step, the lower surface of the backing plate 50 is formed with legs 52 by welding. A plurality of small holes 54 are formed through the three layers 46, 48 and 50 to fix a portion of each of numerical indicia.

Numeral 46a indicates a portion of the soft metal layer 46 which has sagged over a side of the intermediate layer 48 of the hard metal during the press-punching step of the outside diameter of the dial plate. Owing to the sagging portion 46a . the surface layer 46, no special plating pretreatment is necessary. It is thus possible to carry out plating of the dial plate in the same manner as conventionally practiced without the side of the hard metal intermediate layer offering any particular problem. The leg-welding portion of the present invention have no protuberances, due to the intermediate layer 48 of the hard metal clad on the backing layer 50.

Fig. 7 shows a cross-sectional view of a leg-welding portion 58 in the case of a dial plate 56 having a thickness of less than 300 IL and consisting of a single metal material. A protuberance 60 is formed on the surface of the dial plate 56 by the pressure applied to the bottom wall of dial plate at the leg-welding step, the pressure being applied in the directions of arrows 68.

Fig. 8 shows a cross-sectional view of a thin dial plate including the clad metals in accordance with the present invention, after having been subjected to patterning, pressing and leg-welding steps. The dial plate of the Fig. 8 is no defect such as bending or protuberance.

Fig. 9 shows a cross-sectional view of a thin dial plate consisting of the conventional single dial material, after having been subjected to the same machining steps as performed for the dial plate of Fig. 8. The dial plate 62 of Fig. 9 is shown as being bent. A certain degree f of warp has occurred during the patterning and pressing steps.

Example 1 A dial plate and masking plate having an overall thickness of from 100 to 300 it were fabricated using three layers of clad metal materials obtained by combining the metals listed below. The metals designate the surface, intermediate and backing layers in the mentioned order. The combinations are: (1) BS-Ni-BS (2) Cu-Ni-BS (3) BS-SS-BS (4) Cu-SS-BS Table I compiled on the basis of experiments shows overall thickness as well as a thickness for each of the three metal layers. It should be noted that the clad materials listed under the column I are those that are employed in the present Example.

Fig. 10 is a partial cross-sectional view of a dial plate fabricated in accordance with the present invention. The dial plate is provided with a layer 64 of a plated finish, as well as a layer 66 of a clear coating. Employing the abovesaid combinations of materials (1), (2), (3) and (4) made it possible to fabricate a dial plate and mase:in: plate having a thickness of less than 300 IL as well as a conventional pattern without chctnging the customary dial or masking plate manufacturing process and without the aforementioned problems.

Example 2 A decorative front plate having an overall thickness of from 100 to 300 y as well as a variety of colors obtained by anodization and a coloring treatment was fabricated using three layers of clad metal materials obtained by combining the metals listed below. The metals designate the surface, intermediate and backing layers in the mentioned order. The combinations are: (1) Al-Ni-BS (2) Zn-Ni-BS (3) Al-SS-BS (4) Zn-SS-BS Table I, as described above, was compiled on the basis of experiments and shows overall thickness of the front plate as well as a thickness for each of the three metal layers. It should be noted that the clad materials listed under the column "layer Il" are those that are employed in the present Example.Cladding an amphoteric metal on the surface layer of the material in accordance with the present embodiment made it possible to fabricate a thin decorative front plate having a variety of colors as provided by an anodizing and coloring treatment.

Fig. 11 is a cross-sectional view of a blank prior to anodization. It can be seen that the blank has been coated with a resin film layer 70 except for the surface layer 72 which is the layer to be anodized, the film layer 70 serving to prevent the contamination of the intermediate and backing layers 74, 76 during a variety of chemical treatments. The conventional dial plate made of aluminum has little strength at the leg-weld portion and is therefore fabricated with a brass backing plate, to which the legs have already been attached, fixedly bonded to an aluminum surface plate which has been anodized, dyed and subjected to a sealing treatment.The dial plate manufactured in this manner involves high costs and cannot be greatly reduced in thickness, whereas it was possible using the materials in accordance with the present embodiment to mass produce an extremely thin dial at low cost in a simple manner.

Example 3 A decorative front plate having an overall thickness of from 1 OO to 300 IL as well as a sharp patterned quality without requiring a plated finish or clear coating was fabricated using three layers of clad metal materials obtained by combining the metals listed below. The metals designate the surface, intermediate and backing layers in the mentioned order. The combinations are: (1) Au-Ni-BS (2) Au-SS-BS Table II compiled on the basis of experiments shows overall thickness of the decorative plate as well as a thickness for each of the three metal layers.

Fig. 1 2 is a partial cross-sectional view of a dial fabricated using the materials in accordance with the present Example. Cladding gold on the surface layer 78 made it possible to fabricate a thin decorative front plate that not only does not require a plated finish or clear coating but which also exhibits a very sharp pattern.

It should be understood that the metals which constitute the clad layers of the present Example may also be alloyed to present similar effects.

The present invention as described above with respect to Examples thereof has a number of practical effects since it makes possible the manufacture of an extremely expressive decorative front plate having a thickness of from 100 to 300 IL without changing the manufacturing process used to fabricate the conventional decorative front plate, and thus solves the problems of mass production and quality control. This is accomplished by fabricating the decorative front plate from three layers of clad metals, namely a soft metal, hard metal and soft metal in the mentioned order using the proportions disclosed above.

TABLE clad material overall dial thickness layer I II 100it 200cm 300it 1 BSCu Awl sun 45-40 95- 50 145-100 2 Ni 8 SS Ni SSS 10-20 10-100 10-100 3 BS BS 45-40 95- 50 145-100 TABLE II clad material overall dial thickness layer Ill 100it 200it 300it 1 Au 20-40 20- 40 20- 40 2 Ni s SS 10-20 10-100 10-100 3 BS 70-40 170-60 270-160

Claims

1. A decorative front plate for a timepiece, comprising a surface layer composed of a soft material and having an upper surface; an intermediate layer composed of a hard material and attached to a lower surface of said surface layer for reinforcing said decorative front plate; and a backing layer composed of a soft material and attached to a lower surface of said intermediate layer.

2. A decorative front plate according to claim 1, in which said surface layer has a sagging portion sagged over a side of said intermediate layer.

3. A decorative front plate according to claim 1, and further comprising a metallic layer formed on the upper surface of said surface layer.

4. A decorative front plate according to claim 3, and further comprising a clear coating layer formed on an upper surface of said metallic layer.

5. A decorative front plate according to claim 1, and further comprising a protective covering layer formed at a lower surface of said backing layer.

6. A decorative front plate according to claim 5, in which said protective covering layer is composed of resin material.

7. A decorative front plate according to claim 1, in which said surface layer is composed of gold.

8. A decorative front plate according to claim 1, in which said decorative front plate has an overall thickness of about 100 it

9. A decorative front plate according to claim 8, in which said surface layer has a thickness of from 45 to 40 ill said intermediate layer has a thickness of from 10 to 20 ill and said backing layer has a thickness of from 45 to 40 .

10. A decorative front plate according to claim 1, in which said decorative front plate has an overall thickness of about 200 it

11. A decorative front plate according to claim 10, in which siad surface layer has a thickness of from 95 to 50 , said intermediate layer has a thickness of from 10 to 100 ill and said backing has a thickness of from 95 to 50 y.

12. A decorative front plate according to claim 1, in which said deocorative front plate has an overall thickness of about 300 y.

13. A decorative front plate according to claim 12, in which said surface layer has a thickness of from 145 to 100 , said intermediate layer has a thickness of from 10 to 100 Il, and said backing layer has a thickness of from 145 to 100 it.

14. A decorative front plate according to claim 8, in which said surface layer has a thickness of from 20 to 40 ill said intermediate layer has a thickness of from 10 to 20 IL and said backing layer has a thickness of from 70 to 40 it

1 5. A decorative front plate according to claim 10, in which said surface layer has a thickness of from 20 to 40 , said intermediate layer has a thickness of from 10 to 100 , and said backing layer has a thickness of from 170 to 60 it

1 6. A decorative front plate according to claim 12, in which said surface layer has a thickness of from 20 to 40 , said intermediate layer has a thickness of from 10 to 100 , and said backing layer has a thickness of from 270 to 160 y.

17. A decorative front plate substantially as shown and described with reference to Figs. 1 to 3 and 6 to 12 of the accompanying drawings.