JPS6236152Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a train wheel structure for a wristwatch, and an object of the present invention is to provide a train wheel structure particularly suitable for reducing the thickness of a movement.

As wristwatches become smaller and thinner, their internal mechanisms, movements, are also required to be smaller and thinner. Furthermore, it is advantageous to position the reuse, which is an external operating member of the wristwatch, in the direction of the thickness of the movement away from the wrist. That is, when operating the crown to adjust the hands while the wristwatch is worn on the wrist, the closer the crown is to the wrist, the more difficult the operation becomes.

Therefore, it is advantageous to position the crown away from the arm.In other words, it is advantageous to position the winding stem, to which the crown is fixed, closer to the dial side, but generally speaking When the movement was made thinner, the winding stem was positioned extremely close to the case back, making it extremely difficult to operate the reuse.

However, in the past, the small iron wheel was placed on the dial side with respect to the winding stem, but as in the present invention, which will be described later, by placing the small iron wheel on the opposite side of the dial, that is, on the back cover side, it is possible to This makes it possible to move the position closer to the dial side, making it possible to obtain a reuse position that is easy to operate even if the movement is made thinner.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the present invention. The rotating shaft 1a of the center wheel 1 and the second gear 2 are coupled by a constant frictional force. This is because frictional force is generated by sandwiching the sliding part 1b of the rotating shaft 1a with a certain force between the elastic arms 2a of the second gear 2.
This is because the second gear 2 is coupled to the rotating shaft 1a. Further, the pointer correction transmission gear 1d is fixed to the rotating shaft 1a by being pushed. In addition, the second gear 2
is arranged on the dial 10 side with respect to the pointer correction transmission gear 1d.

During normal driving, the rotation transmitted from the step motor, which is the power source, to the second gear 2 through a well-known front wheel train consisting of a fifth wheel, fourth wheel, third wheel, etc. 2 to the rotating shaft 1a coupled to the rotating shaft 1a through frictional force, and the minute hand 1c attached to the rotating shaft 1a is moved.

Further, the rotation of the rotating shaft 1a is reduced to 1/12 by the Hinoura wheel 6 that meshes with the pinion 1e provided on the rotating shaft 1a.
The speed is decelerated and transmitted to the hour wheel 7, and the hour hand 7a attached to the hour wheel 7 is moved. On the other hand, when the pointer is corrected by external operation, the rotation of the crown is transferred from the winding stem 5 fixed to the crown to the knob wheel 4.
is transmitted to the small iron car 3 via
The pointer correction transmission gear 1d meshing with the pointer correction transmission gear 1d is transmitted to the fixed rotating shaft 1a. At this time, the second gear 2
is restrained from rotating by applying a brake to a part of the front wheel train, and as a result, the rotating shaft 1a slips and rotates with respect to the second gear 2, causing the pointer to change. Correction (so-called needle alignment) will be performed.

The small iron wheel 3 is disposed on the opposite side of the dial 10 from the winding stem 5, that is, on the side of the back cover (not shown).

On the other hand, in the past, the Hinoura wheel was configured to mesh with the small iron wheel, and also played the role of transmitting the rotation of the small iron wheel to the center wheel and hour wheel, but in the present invention, the small iron wheel 3
Since the Hinohira wheel 6 is not interposed in the transmission path leading to the center wheel 1, it is possible to reduce the dimension from the center of the movement to the end corresponding to the 3 o'clock direction on the dial. can be downsized.

Next, other structural trains of the center wheel in the above-mentioned wheel train structure of the present invention will be described.

FIG. 2 is a sectional view showing another example of the structure of the center wheel, in which the pointer correction transmission gear 1 is fixed to the rotating shaft 1a.
A spring member (such as a disk spring) 8 is sandwiched between d and the second gear 2, and a constant frictional force generated by the spring force of the spring member 8 causes the rotating shaft 1a to
and the second gear 2 are frictionally coupled to be able to slip.

FIG. 3 is a sectional view showing still another example of the structure of the center wheel. In this embodiment, instead of the spring member 8 shown in FIG. It is being

As described above, according to the present invention, first place the small iron wheel on the opposite side of the dial to the winding stem (i.e., on the back cover side).
By arranging the winding stem, it is possible to bring the winding stem closer to the dial, and as a result, even if the movement is made thinner, it is possible to prevent the reuse operation from becoming difficult. At the same time, a pointer correction transmission gear is fixedly attached to the rotating shaft of the center wheel on which the minute hand is mounted, and a second gear configured to be able to slip is attached to the pointer correction transmission gear. The small iron wheel is mounted so as to be located on the plate side, the small iron wheel is meshed with the pointer correction transmission gear, and the center wheel is normally driven by frictional coupling between the second gear and the rotating shaft. As a result, the step motor reaches the second gear. It becomes possible to obtain a transmission path for pointer correction from the small iron car to the rotating shaft without becoming an obstacle to the arrangement of the so-called front wheel train.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a wheel train structure according to an embodiment of the present invention. FIGS. 2 and 3 are cross-sectional views of another structural example of the center wheel according to the present invention and still another structural example. 1... Center wheel, 1a... Rotating shaft, 1a... Minute hand, 1d... Pointer correction transmission gear, 2... Second gear, 2a... Elastic arm, 3... Small iron wheel, 4... Tsutsumi wheel. , 5... Makishin, 6... Hinouraguruma, 7... Tsutsuguruma.

Claims (1)

[Scope of utility model registration request] In a wristwatch having at least a small iron wheel provided for transmitting the rotation of the winding stem to the pointer when the pointer is corrected, and a central wheel having a minute hand attached to the rotating shaft, the small iron wheel is placed relative to the winding stem. The pointer correction transmission gear disposed on the opposite side of the dial and fixed to the rotating shaft of the center wheel meshes with the small iron wheel,
Moreover, a second gear frictionally coupled to a part of the rotating shaft and configured to be able to slip with respect to the rotating shaft is disposed on the dial side with respect to the pointer correction transmission wheel. A wheel train structure for a wristwatch, characterized in that the center wheel is driven by frictional coupling between a number gear and the rotating shaft.