SUPER HARD WRISTTWATCH CASE

Abstract

 A super hard wristwatch case, where fractures, cracks and/or breaks are prevented from being produced in leg portions of a case body on installation and removal of spring rods for installing a wristwatch band, is disclosed. This is achieved by a simple modification to the structure of the wristwatch case. The super hard wristwatch case is provided with a shock-resistant metallic back cover (2) having left/right pairs of projection pieces (20a, 20b, 21a, 21b) provided on a surface thereof which faces a case body (1), the projection pieces being located so as to be opposed to inner wall faces of the leg portions (11a, 11b, 12a, 12b), the projection pieces being formed with fixing holes (22a, 22b, 23a, 23b) for spring rods (3) in regions thereof that are adjacent tips of the projection pieces, the projection pieces being fitted and fixed in the inner wall faces of the leg portions. The spring rods (3) are bridged and engaged between the projection pieces (20a, 20b, 21a, 21b).

Description

TECHNICAL FIELD

[0001] This invention relates to an improvement of a super hard wristwatch case which includes a case body of a super hard material having left/right pairs of leg portions provided at opposite positions thereof, and in which a wristwatch band is supported between the leg portions by means of spring rods.

BACKGROUND ART

[0002] Hitherto, there is known a wristwatch case in which left/right pairs of leg portions are provided at opposite positions of a case body and a wristwatch band is attached between the leg portions by means of spring rods (Japanese Patent Application Laid-Open Nos. Hei. 7-231802 and Hei. 10-225309). In the wristwatch case, fixing holes between which the spring rods are to be bridged and engaged are formed in inner wall faces of the leg portions.

[0003] As the wristwatch case, there is known a wristwatch case in which a case body is formed of a hard material that is poor in machinability, such as sintered carbide and ceramics. Also, in a super hard wristwatch case, fixing holes for spring rods are formed in inner wall faces of leg portions by applying an electric discharge machining technique directly to the inner wall faces of the leg portions.

[0004] In the super hard wristwatch case, on installation and removal of the wristwatch band, fractures, cracks and/or breaks are easily produced in regions of the leg portions around the fixing holes by the installation and removal operations and/or impact applied to the leg portions by a spring action of the spring rods. This may be often a problem in a visual appearance of the wristwatch case. The causes include physical properties on the hard material of the case body that is easy to be broken, as well as microcracks which will be produced due to transformation in a surface layer of the case body which is subjected to the electric discharge machining.

DISCLOSURE OF THE INVENTION

[0005] It is an object of this invention to provide a super hard wristwatch case which is modified so that installation and removal of spring rods for supporting a wristwatch band will not cause fractures, cracks and/or breaks to be produced in leg portions of a case body. This is achieved by a simple modification to the structure of the wristwatch case.

[0006] In accordance with the present invention, there is provided a super hard wristwatch case. The super hard wristwatch case comprises a case body of a super hard material having left/right pairs of leg portions or left/right pairs of portions corresponding in shape to the leg portions, the leg portions being provided at opposite positions of the case body, a back cover attached and fixed to a back of the case body, and installation spaces between the leg portions for spring rods for supporting a wristwatch band between the left/right leg portions therethrough. Shock-resistant metallic members which have fixing holes for the spring rods are provided in inner wall faces of the installation spaces. The spring rods are bridged and engaged between the metallic members.

[0007] In a preferred embodiment of the present invention, the back cover is formed of shock-resistant metal and has left/right pairs of projection pieces provided on a surface thereof which faces the case body. The left/right pairs of the projection pieces are located so as to be opposed to the inner wall faces of the leg portions of the case body. The projection pieces are formed with fixing holes for the spring rods in regions thereof which are adjacent tips of the projection pieces. The projection pieces of the back cover are fitted and fixed in the inner wall faces of the leg portions. The spring rods are bridged and engaged between the projection pieces. The case body has notches formed in the inner wall faces of the leg portions thereof. In this case, the back cover is fixed to the back of the case body with the projection pieces thereof being fitted and fixed in the notches of the leg portions so as to be flush with the inner wall faces of the leg portions.

[0008] In another preferred embodiment of the present invention, the case body is provided with shock-resistant metallic tubing members embedded in the inner wall faces of the leg portions, the tubing members having the fixing holes for the spring rods. The spring rods are bridged and engaged between the tubing members.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] 

Fig. 1 is an exploded perspective view of a super hard wristwatch case according to a first embodiment of the present invention;

Fig. 2 is a segmentary perspective view of the super hard wristwatch case of Fig. 1;

Fig. 3 is a fragmentary sectional view of the super hard wristwatch case of Fig. 1;

Fig. 4 is a segmentary perspective view of a super hard wristwatch case according to a second embodiment of the present invention, in which a tubing member is removed from a case body; and

Fig. 5 is a fragmentary sectional view of the super hard wristwatch case of Fig. 4, in which the tubing member and a spring rod are attached to the case.

MODES FOR CARRYING OUT THE INVETION

[0010] Embodiments according to the present invention will be discussed hereinafter with reference to the accompanying drawings. As shown in Fig. 1, an illustrated embodiment includes a case body 1, a back cover 2 and spring rods 3 (only one spring rod 3 is shown in Fig. 1), and is assembled as a wristwatch case in which a wristwatch band 4 is adapted to be supported by the spring rods 3. The case body 1 is formed of a super hard material such as sintered carbide and ceramics. The back cover 2 is formed of shock-resistant metal such as stainless steel.

[0011] The case body 1 comprises an outer frame 10 serving as a body, and is provided with left/right pairs of leg portions 11a, 11b, 12a, 12b at opposite positions of the outer frame 10. Installation space 13 (generally referred to as "fitting part fork part", viz., "Kanmata" in wristwatch fabrication terminology in Japanese) for the spring rods 3 for supporting the wristwatch band 4 between the leg portions 11a, 11b, 12a, 12b therethrough are provided between the leg portions 11a, 11b, 12a, 12b. The back cover 2 is formed into a flat plate having a contour that allows the back cover 2 to be fitted in the back of the outer frame 10 including the leg portions 11a, 11b, 12a, 12b. Each of the spring rods 3 comprises a sleeve 3c, a coil spring (not shown) housed within the sleeve 3c, and left/right protruding pins 3a, 3b elastically supported to the coil spring.

[0012] In order to cause the spring rods 3 to be bridged and engaged between the leg portions, on the basis of the wristwatch case assembled from the respective components described above, shock-resistant metallic members are provided in inner wall faces of the leg portions 11a, 11b, 12a, 12b. The concrete examples include a first embodiment of the present invention in which the back cover 2 shown in Figs. 1 to 3 is employed, and a second embodiment of the present invention in which tubing members shown in Figs. 4 and 5 (only one tubing member is shown in Figs. 4 and 5) are employed.

[0013] In the first embodiment, left/right pairs of projection pieces 20a, 20b, 21a, 21b are provided at the back cover 2. The projection pieces 20a, 20b, 21a, 21b are formed integrally with the back cover 2, rise up from a surface of the back cover 2 which faces the case body 1, and serve as the metallic members having the same impact resistance as the back cover 2 does. The projection pieces 20a, 20b, 21a, 21b are formed with fixing holes 22a, 22b, 23a, 23b for the spring rods in regions thereof that are adjacent tips of the projection pieces 20a, 20b, 21a, 21b.

[0014] The case body 1 is formed in inner wall faces of the leg portions 11a, 11b, 12a, 12b thereof with notches 14 (only one notch 14 is shown in Fig. 1) in which the projection pieces 20a, 20b, 21a, 21b are to be fitted. The notches 14 are formed so as to have contours and depths which allow the projection pieces 20a, 20b, 21a, 21b to be fitted in the notches 14 so as to be flush with the inner wall faces of the leg portions 11a, 11b, 12a, 12b. The four notches 14 can be easily formed at the same time by causing the leg portions to be subjected to electric discharge machining from the same direction.

[0015] Necessary components which include a movement, a dial, an armor glass, etc. are assembled to the case body 1 constructed as discussed above. The back cover 2 is then applied to the back of the case body 1 and assembled to the case body 1 by screwing four pins 5a, 5b, 5c (only three pins are shown in Fig. 1) into through-holes 24a, 24b, 25a, 25b of the back cover 2 and then screwing them into the case body, whereby the super hard wristwatch case or a wristwatch is assembled.

[0016] In the wristwatch case constructed as discussed above, as shown in Fig. 2, the projection pieces of the back cover 2 (only one projection piece 20a is shown in Fig. 2) are fitted and fixed in the notches 14 of the leg portions (only one leg portion 11a is shown in Fig. 2) and flush with the inner wall faces of the leg portions so as not to be exposed to the exterior, so that the wristwatch case can be assembled so as to have a form usual in an ornamental design.

[0017] When the wristwatch band 4 is to be attached to the wristwatch case, as shown in Fig. 3, the projecting pins of the spring rods 3 are fitted in the fixing holes of corresponding projection pieces, whereby the spring rods 3 are bridged and engaged between the corresponding projection pieces (only the projecting pin 3a and the fixing hole 22a of the projection piece 20a are shown in Fig. 3). The projection pieces are formed integrally with the back cover 2 as the metallic members which are formed of shock-resistant metal such as stainless steel as discussed above, so that any impact applied to the projection pieces on installation and removal of the spring rods will not cause any fractures, cracks and/or breaks to be produced in the projection pieces.

[0018] In addition, it is unnecessary to provide fixing holes for the spring rods in the leg portions of the case body and the leg portions of the case body 1 can be reinforced by the projection pieces of the back cover, so that fractures, cracks and/or breaks will be prevented from being produced in the leg portions of the case body 1.

[0019] In the second embodiment, as shown in Fig. 4 (illustrating only part of the wristwatch case according to the second embodiment), cylindrical tubing members 6 (only one tubing member 6 is shown in Fig. 4) are provided as the metallic members that are formed of shock-resistant metal such as stainless steel. The tubing members 6 have bores 6a serving as the fixing holes for the spring rods and are embedded in the inner wall faces of the leg portions (only one leg portion 11a is shown in Fig. 4). Also, counter bored-holes 15 (only one counter bored-hole 15 is shown in Fig. 4) are formed in the inner wall faces of the leg portions, in which the tubing members 6 are fitted and then firmly fixed by brazing for example.

[0020] In this embodiment, as shown in Fig. 5, the projecting pins of the spring rods (only one projecting pin 3a of a spring rod 3 are shown in Fig. 5) are fitted in the bores of the tubing members 6, whereby the spring rods 6 are bridged and engaged between corresponding tubing members 6. The tubing members 6 are formed as the metallic members that are formed of shock-resistant metal such as stainless steel, so that shock produced by installation and removal of the spring rods 3 will not cause fractures, cracks and/or breaks to be produced in the tubing members 6. Also, the leg portions of the case body 1 can be reinforced by the tubing members 6, so that any fractures, cracks and/or breaks will be prevented from being produced in the leg portions of the case body 1.

[0021] As discussed above, the super hard wristwatch case according to the present invention is provided with the shock-resistant metallic back cover having the left/right pairs of the projection pieces provided on the surface thereof which faces the case body, the left/right pairs of the projection pieces being located so as to be opposed to the inner wall faces of the leg portions of the case body, the projection pieces being formed with the fixing holes for the spring rods in the regions of the projection pieces which are adjacent the tips of the projection portion, and the projection pieces of the back cover being fitted and fixed in the inner wall faces of the leg portions. Alternatively, the shock-resistant metallic tubing members that have the bores serving as the fixing holes for the spring rods are embedded in the inner wall faces of the leg portions. The spring rods for supporting the wristwatch band are bridged and engaged between the projection pieces or the tubing members. Thus, the simple modification to the structure of the wristwatch case, in which the spring rods for supporting the wristwatch band are bridged and engaged between the projection pieces or the tubing members, can prevent any fractures, cracks and/or breaks from being produced in the leg portions of the case body on the installation and removal of the spring rods from the case.

[0022] In one of the above-described embodiments, or in the case where the projection pieces having the fixing holes for the spring rods are provided at the back cover, the back cover is assembled and fixed to the case body with the projection pieces thereof being fitted in the notches of the leg portions so as to be flush with the inner wall faces of the leg portions, so that the wristwatch case can be assembled so as to have a form usual in an ornamental design.

[0023] Incidentally, the terms and expressions which have been employed are used as terms of description, not of limitation. For example, the term "left/right pairs of leg portions" is given to mean both the left/right pairs of the leg portions and left/right pairs of portions corresponding in shape to the left/right leg portions. There is no intention in the use of such terms and expressions of excluding any equivalents of the elements or features shown and described or portions thereof. It is recognized that various modifications are possible within the scope of the invention claimed.

Claims

1. A super hard wristwatch case comprising:

a case body of a super hard material having left/right pairs of leg portions or left/right pairs of portions corresponding in shape to said leg portions that are provided at opposite positions of said case body;

a back cover attached and fixed to a back of said case body; and

installation spaces between said leg portions for spring rods for supporting a wristwatch band between said leg portions, characterised in that said case includes shock-resistant metallic members having fixing holes for said spring rods, said metallic members being provided in inner wall faces of said installation spaces of said leg portions, and said spring rods are bridged and engaged between said metallic members.

2. The super hard wristwatch case according to claim 1, characterised in that said back cover is formed of shock-resistant metal and has left/right pairs of projection pieces provided on a surface thereof which faces said case body, said left/right pairs of said projection pieces being located so as to be opposed to said inner wall faces of said leg portions of said case body, said projection pieces being formed with fixing holes for said spring rods in regions thereof which are adjacent tips of said projection pieces, said projection pieces of said back cover being fitted and fixed in said inner wall faces of said leg portions, and said spring rods being bridged and engaged between said projection pieces.

3. The super hard wristwatch case according to claim 2, characterised in that said case body has notches formed in said inner wall faces of said leg portions thereof, and said back cover is fixed to said back of said case body with said projection pieces thereof being fitted and fixed in said notches of said leg portions so as to be flush with said inner wall faces of said leg portions.

4. The super hard wristwatch case according to claim 1, characterised in that said case body is provided with shock-resistant metallic tubing members which are embedded in said inner wall faces of said leg portions, said tubing members having said fixing holes for said spring rods, and said spring rods are bridged and engaged between said tubing members.

Drawing