JPH07167969A - Screw pipe structure for timepiece - Google Patents

Abstract

PURPOSE:To reduce the fall of a screw at the thread fastening time even in a thin type movement such as a wrist watch so as to improve workability and productivity. CONSTITUTION:The screw insert opening of a screw pipe 10 is provided with a guide hole 10a of 1.5 pitch in depth. At the screwing time, the movement of a screw 7 in the direction of an arrow mark Fd is regulated by the side part of the guide hole 10a so as to put the screw 7 into the self-supporting state. When the screw 7 is rotated in this state, the screw 7 is desirably connected to the screw pipe 10. Workability and productivity can be therefore improved while contributing to making a movement lightweight and thin since the thickness of a ring row receiver 5 can be freely designed regardless of the guarantee of self-supportability of the screw.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a threaded pipe structure for a wristwatch, and more particularly to an improvement to screw mounting.

[0002]

2. Description of the Related Art As a conventional threaded pipe structure for a wristwatch, there is one shown in FIGS. What is shown in FIG.
As shown in an exploded view in FIG. 4, the stator 2, the magnetic core 3, the spacer 4, and the train wheel bridge 5a are sequentially stacked and positioned on the screw pipe 6 press-fitted and fixed to the main plate 1 (see arrow Fa). In this state, as shown in FIG. 3 (A), the screw 7 is erected on the screw pipe 6 and screwed (rotated and inserted).
However, the screw 7 tilts as shown by the arrow Fc. Therefore, the screw 7 is screwed by supporting the screw 7 with a hand or a jig (not shown) and rotating it while ensuring the posture (see arrow Fb in FIG. 4). FIG. 3 (B) shows a state in which the screw 7 is screwed into the screw pipe 6.

Next, in the conventional example shown in FIG. 5, in order to secure the self-standing property when the screw 7 is erected on the screw pipe 6, the train wheel bridge 5b is made thicker than in the conventional example. Note that other members may be thickened. Thus, in the conventional example, the chamfer 6a of the screw pipe 6 is located substantially on the surface of the train wheel bridge 5a, whereas in the conventional example, the chamfer 6a is located deeper than the train wheel bridge 5b.

As shown in FIG. 5 (A), when the screw 7 is raised, the inclination of the screw 7 shown by arrow Fc in FIG. 3 (A) is restricted by the thickness of the train wheel 5. In this way, the screw 7 is screwed while making the screw 7 self-supporting.
As shown in (B).

[0005]

However, the above conventional techniques have the following disadvantages. (1) First, in the conventional example shown in FIG.
Hands and jigs are required to achieve self-reliance. For this reason, workability and productivity are poor, and jigs must be arranged.

Further, in the conventional example shown in FIG. 5, the train wheel bridge 5
Since the screw 7 and the like are thickened to make the screw 7 self-supporting, the thickness of the movement (timepiece mechanism portion) also increases.
Therefore, the result is contrary to the demand for weight reduction and thickness reduction of the timepiece. The present invention focuses on these points, and can reduce the fall of the screw at the time of screwing to improve the workability and the productivity, and to provide a timepiece suitable for reducing the weight and thinning the movement. It is an object to provide a threaded pipe structure.

[0007]

To achieve the above object, the present invention provides a screw pipe structure of a timepiece for fixing a member of a movement by screwing a screw into a screw pipe press-fitted and fixed to a main plate. A guide hole having a diameter larger than the screw diameter is provided in the screw insertion port of the threaded pipe, and the depth of the guide hole is set to 1.5 pitches or more of the screw pitch.

[0008]

According to the present invention, the threaded pipe is provided with a guide hole, and the depth of the guide hole is set to be 1.5 pitches or more in thread pitch. For this reason, the self-supporting property when the screw is raised is improved, and the screwing work can be easily performed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a threaded pipe structure for a timepiece according to the present invention will be described below in detail with reference to the accompanying drawings. The same reference numerals are used for the same components as those of the above-described conventional technique or components corresponding to the conventional technique. FIG. 1 shows a cross section of this embodiment.
This figure corresponds to FIG. 3 or FIG. In the figure, the screw pipe 10 is press-fitted and fixed to the main plate 1 as in the conventional example. Then, as shown in FIG. 4, the stator 2, the magnetic core 3, the spacer 4, and the train wheel bridge 5 are sequentially stacked on the main plate 1 as shown in FIG.

By the way, in this embodiment, as shown in an enlarged view in FIG. 2, the guide hole 1 is provided at the screw insertion port of the screw pipe 10.
0a is provided. The diameter Da of the guide hole 10a is set larger than the diameter Db of the screw 7, and the depth Dc thereof is set to be 1.5 pitches or more of the thread pitch of the screw 7. Next, the operation of this embodiment will be described. At the time of assembly, the tip of the screw 7 is inserted into the guide hole 10a of the screw pipe 10 as shown in FIG. Then, when the screw 7 is rotated in this state, the screw 7 is screwed into the screw pipe 10 as shown in FIG.

In this case, in this embodiment, the depth Dc of the guide hole 10a of the threaded pipe 10 is 1.5 of the threaded portion.
It has become the pitch. In order to properly regulate the screw 7 so as to be self-supporting, the guide hole 10a needs to have a certain depth or more. Here, whether or not the screw 7 is self-supporting well depends on the screw pitch. That is, when the screw pitch is large, unless the screw 7 is inserted into the screw pipe 10 relatively deeply, the ridges and valleys of both screws do not mesh well. However, when the screw pitch is small, even if the screw 7 is inserted relatively shallowly into the screw pipe 10, the peaks and troughs of both screws can be meshed well.

Therefore, in this embodiment, the depth Dc of the guide hole 10a is set to 1.5 or more of the screw pitch in order to secure good self-sustaining property of the screw 7. Experiments have shown that if the pitch is 1.5 pitches or more, the practically sufficient self-sustaining property of the screw 7 can be secured. Further, in the conventional example of FIG. 5, the distance Ea between the inside of the train wheel bridge 5b and the screw 7 is substantially equal to the wall thickness of the screw pipe 6. However, in the present embodiment, the interval Eb between the inside of the guide hole 10a and the screw 7 is the thickness of the threaded pipe 10 minus the thickness of the guide hole 10a, and Ea> Eb. In this way, in the present embodiment, the interval is narrower and there is no play, so that also from this point, the self-supporting property of the screw 7 is well secured.

It should be noted that a method of obtaining the same effect as that of the present embodiment is conceivable by setting the hole of the train wheel bridge 5b as a stepped portion as shown in FIG. 5C so that Ea = Eb. However, this method complicates the processing of holes and increases the cost.
The processing of the guide hole 10a of the present embodiment is an alternative to the threaded tap guide processing that has been conventionally performed, so that the required effect can be obtained without increasing the cost.

For the above reasons, the arrow F of the screw 7
The movement in the d direction (see FIG. 1 (A)) is regulated by the side portion of the guide hole 10a, and the screw 7 is favorably self-supporting. When the screw 7 is rotated in this state, the screw 7 is connected to the screw pipe 10 as shown in FIG.

As described above, according to this embodiment, since the thread pipe 10 is provided with the guide hole 10a, the interference between the screw pipe 10 and the screw 7 can be favorably secured, so that the train wheel bridge 5 can be made thin. It is possible to suppress the maximum thickness of the movement as much as possible. by this,
By reducing the fall of the screw at the time of tightening, it is possible to improve workability and productivity, and contribute to weight reduction and thickness reduction of the movement. Further, by providing the guide hole 10a, the threaded portion of the threaded pipe 10 can be shortened, the breakage of the tap can be prevented, and the service life can be extended.

The present invention is not limited to the above embodiment, and includes, for example, the following. (1) The member to be sandwiched and fixed between the screw pipe and the screw may be any member other than the member shown in the above embodiment. Moreover, the number of members to be overlapped is also arbitrary. (2) The present invention is suitable for thin movements such as wrist watches, but is also effective for various small and portable watches such as pocket watches and pendants.

[0017]

As described above, according to the present invention,
A guide hole is provided at the screw insertion port of the threaded pipe, and the depth is set to 1.5 pitches of the thread pitch or more, so the self-supporting property of the screw at the time of tightening becomes good, and workability and productivity are improved. Therefore, there is an effect that the movement can be made thinner.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a threaded pipe structure of the present invention during screw insertion and screw tightening.

FIG. 2 is an enlarged sectional view showing a threaded pipe and a screw in the embodiment.

FIG. 3 is a cross-sectional view showing a screw pipe structure of a first conventional example at the time of screw insertion and screw tightening.

FIG. 4 is an explanatory view showing each part of the conventional example in an exploded manner.

FIG. 5 is a cross-sectional view showing a screw pipe structure of a second conventional example at the time of screw insertion and screw tightening, and a cross-sectional view showing the screw tightening of a third conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Base plate 2 ... Stator 3 ... Magnetic core 4 ... Spacer 5,5a, 5b ... Train wheel receiving 6,10 ... Screw pipe 6a ... Screw pipe chamfer 10a ... Screw pipe guide hole 7 ... Screw Da ... Guide hole diameter Db … Screw diameter Dc… Depth of guide hole Ea, Eb… Gap

Claims (1)

[Claims] 1. A screw pipe structure of a timepiece for fixing a member of a movement by screwing a screw into a screw pipe press-fitted and fixed to a main plate, wherein a diameter larger than a screw diameter is provided at a screw insertion port of the screw pipe. A threaded pipe structure for a timepiece, characterized in that a guide hole having a hole is provided, and the depth of the guide hole is set to 1.5 pitches or more of the thread pitch.