JPH08112115A - Connecting structure of wristwatch case and band - Google Patents

Abstract

PURPOSE: To connect a cemented carbide case with a cemented carbide band by providing both a screw bushing that has been brazed to the hole which has been formed below the end piece of a band made of cemented carbide metal and an end ring that has been fixed by the screw bushing, and by connecting the end ring with the watch case. CONSTITUTION: A wristwatch case is made of a cemented carbide metal such as tantalum carbide or tungsten carbide, and the side part 1 thereof is provided with a recessed part 2 on its underside for connecting a band. The underside of the recessed part 2 for connecting the band 3 is open, and supporting parts 4 are formed on both sides thereof, and therein fitting holes 6 to which the pins 5a on both the ends of a spring rod 5 are inserted are provided. The band 3 is also made of the same cemented carbide metal. The spring rod 5 is inserted into the holding part 10a of the end ring 10, and the spring rod 5 is held by the cylindrical part 5b thereof. In this condition, the end ring 10 is inserted into the recessed part 2 of the case, and the pin 5a is inserted into the fitting holes 6 for completing the connection. In this state, a stopper part 10b abuts on the upper surface of the recessed part 2, and the case and the band are relatively turned.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connecting structure for a wristwatch case and a band, and more particularly to a connecting structure for a case and a band made of superhard metal.

[0002]

2. Description of the Related Art A stainless steel tip can is spot-welded to the tip of a metal band, and the tip can is connected to a leg of a watch case by a spring rod. However, spot welding is not possible if the band is made of cemented carbide. Therefore, it is possible to fix the tip can to the carbide band by brazing, but since the thermal expansion coefficient is different between stainless steel and cemented metal and the brazing area is large, the carbide band may crack or break. So
Brazing is also impossible.

On the other hand, conventionally, there is a method in which the tip can is directly connected to the metal band with a screw. However, it is not possible to thread female threads on bands made of cemented carbide. On the other hand, Japanese Utility Model Publication No. 62-68606 discloses a structure in which a screw bush is brazed to a band and the watch case is directly fixed to the screw bush with a screw. According to this structure, even a carbide band can be connected to the case with a screw.

[0004]

However, when the watch case is made of superhard metal, the screw fitting portion of the case is damaged when the screw is tightened, and the watch case cannot be connected. Therefore, an object of the present invention is to provide a structure capable of connecting a cemented carbide case and a cemented carbide band.

[0005]

The connection structure between a wristwatch case and a band according to the present invention is a screw bush which is brazed to a hole formed in the lower side of a tip piece of a band made of cemented metal and a screw thereof. The front can is fixed to the bush with a screw, and the front can is connected to the watch case.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. Watch case is made of tantalum carbide (TaC)
Alternatively, it is made of a superhard metal such as tungsten carbide (WC), on the side 1 of which a recess 2 is formed on the lower side in the band connection. The recess 2 has a connection surface with the band 3 and a lower surface opened, and support portions 4 are formed on both sides, and mounting holes 6 into which the pins 5a at both ends of the spring rod 5 are inserted are provided therein.

The band 3 is also made of the above-mentioned hard metal. Here, for example, in the case of tantalum carbide, its components are as shown in Table 1.

[0008]

[Table 1]

According to the present invention, two blind holes 7 are formed on the lower side of the piece 3a at the tip of the band so as to be aligned in the width direction of the band. In the case of TaC, the inner wall of the hole is nickel plated. This is in order to improve the flow of gold roW, which will be described later. A suitable plating thickness is 1 to 3 μm.

In the hole 7, a cylindrical screw bush 8 having an internal thread is brazed with a gold braze. Table 2 shows the composition of gold wax.

[0011]

[Table 2]

This brazing material can be used for both TaC and WC.
The tip can 10 is made of stainless steel, and is fixed to the band 3 by screwing a screw 11 into the blind hole 7. The tip can 10 has a holding portion 10a that holds the cylindrical portion 5b of the spring rod 5, and a stopper portion 1 that curves upward and contacts the upper surface of the recess 2 on the side 1.
With 0b.

To connect the tip of the band to the case as described above, the spring rod 5 is inserted into the holding portion 10a of the tip can 10, and the spring rod is held by the tubular portion 5b. Next, the spring rod 5
With the pin 5a of 1) being pushed in, the tip can 10 is inserted into the recess 2 of the case, and then inserted into the pin 5a and the mounting hole 6 to complete the connection. In this state, the stopper portion 10b hits the upper surface of the recess 2 and the case and the band rotate relatively.
That is, the band is prevented from rotating clockwise in FIG. On the other hand, the upper end 3b of the piece 3a of the band is on the side 1
It contacts the outer wall of the band and prevents the band from rotating counterclockwise.

[0014]

As is apparent from the above, the connection structure according to the present invention has a screw bush by brazing to a hole formed in the lower side of the tip piece of a band made of cemented metal and a screw on the screw bush. Because the tip can is fixed and the tip can is connected to the watch case, even if the tip can and the carbide band have different coefficients of thermal expansion, the band can be made of stainless steel without damaging the band. It is possible to fix the manufactured can. Therefore, the front can can be easily fixed to the watch case.

[Brief description of drawings]

FIG. 1 is a cut-away side view showing one embodiment of the present invention.

2 is an exploded perspective view of the structure of FIG. 1. FIG.

[Explanation of symbols]

 1 side 2 recessed part 3 band 3a piece 3b tip upper part 4 support part 5 spring rod 5a pin 5b cylinder part 6 mounting hole 7 blind hole 8 screw bush 10 tip can 10a holding part 10b stopper part 11 screw

Claims (3)

[Claims] 1. A screw bushing brazed to a hole formed in a lower side of a tip piece of a band made of cemented carbide, a tip can fixed to the screw bush by a screw, the tip can and a watch. A structure for connecting a wristwatch case and a band, which comprises connecting means for connecting the case. 2. The connection structure between a wristwatch case and a band according to claim 1, wherein the watch case is made of a super hard metal. 3. The structure for connecting a wristwatch case and a band according to claim 1, wherein the connecting means comprises a spring rod attached to the front can and a pin attaching hole of the spring rod provided in the case. .