JPH06105308B2 - Clock pointer correction device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to an improvement of a pointer correction device for a timepiece.

[Background of the Invention]

In recent years, the application technology of plastics has become popular, and even in watches, cost reduction is rapidly promoted by using plastic parts, and plastic materials are also adopted for parts of the main plate, wheel train bridge, front wheel train, etc. Became. However, in the back wheel train that constitutes the timepiece correction device of the timepiece, the back wheel train made of a metal material is used in order to ensure the mechanical strength of the back wheel train, and the needle correction torque of the winding stem is high. There is. Therefore, there has been a demand for a new pointer correction device having a low pointer correction torque that enables the back wheel train to be made of plastic.

[Conventional technology and problems]

FIG. 1 and FIG. 2 are cross-sectional views of essential parts showing a timepiece pointer correction device according to the prior art.

In the conventional general pointer correction device, the corner of the winding stem 1
The winding wheel 2 is slidable on the lathe 1a in the axial direction of the winding stem, and is engaged with the winding stem 1 so as to rotate integrally with the lathe in the rotating direction. Pull out the true 1,
When the winding stem 1 is set to the pointer correction position as shown in Fig. 2,
The crown wheel 2 slides by the mandrel 3 which operates in conjunction with the winding stem 1 and the hook 4 which is engaged with the mandrel 3,
When meshing with the setting wheel 5 is performed and the winding stem 1 is rotated,
The minute hand wheel 7 is rotated from the Tsuzuki wheel 2 through the small iron wheel 5 and the Hino back wheel 6 to correct the pointer. At that time, in order to prevent the pointer maintenance torque transmitted to the minute hand wheel 7 from being transmitted to the power train, the minute hand gear 7b of the minute hand wheel 7 is
It receives the braking force of a braking device (not shown) built in the wheel train structure on the power side. Furthermore, minute hand wheel 7
Has a so-called slip mechanism in which the minute hand gear 7b is slidably fitted to the shaft portion 7a of the minute hand wheel 7, and therefore, when the pointer correction torque is transmitted to the shaft portion 7a of the minute hand wheel 7, Since the shaft portion 7a of 7 rotates by slipping with the minute hand gear 7b that receives the braking force by the brake device, the time can be corrected normally.

The slip torque value between the shaft portion 7a of the minute hand wheel 7 and the minute hand gear 7b when the hands are corrected is set to approximately 2 g.cm to 8 g.cm or more. Therefore, the pointer correction torque value at the time of the winding stem operation in the conventional back wheel train is almost equal to or higher than the slip torque value between the shaft portion 7a of the minute hand wheel 7 and the minute hand gear 7b,
Since the diameter of the gear module of the small iron wheel etc. used for the watch size movement is about 0.9 to 0.16 mm, considering the strength and durability of the teeth, the material of Tsutsumi wheel, small iron wheel etc. is metal. Therefore, it was difficult to make plastic with the conventional pointer correction device, and the cost was high.

[Object of the Invention]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above drawbacks and to provide a pointer correction device that contributes to cost reduction by making the back wheel train, which is a pointer correction device, plastic.

[Structure of Invention]

In the pointer correcting device of the present invention, in the pointer correcting state, the spiral wheel that rotates by the rotating operation of the winding stem directly meshes with the pointer correcting transmission gear that is integrally provided with the rotating shaft of the third wheel with the slip structure. It is characterized by that.

Example of Invention

Embodiments of the present invention will be described below with reference to the drawings. Third
FIGS. 4A and 4B are sectional views showing the main part of the pointer correcting device according to an embodiment of the present invention.

The third wheel & pinion 10 is a gear 10 for transmitting a pointer correction that meshes with the wheel and wheel 11.
a, a rotary shaft pinion 10e that meshes with the minute hand gear 13a of the minute hand wheel 13, a sliding portion 10c, and a rotary shaft 10b are integrally molded of a plastic material,
The sliding portion 10c is provided with a slip mechanism composed of a third slip gear 10d having an elastic arm portion and slip-fitted with a constant spring force. FIG. 3 shows a normal winding stem 12 position. The crown wheel 11 is formed by molding a plastic material, and the hole has a two-step hole shape with a fine hole portion 11a and a tip hole portion 11b. The small hole portion 11a and the tip hole portion 11b are loosely fitted in the small diameter portion 12a and the tip shaft portion 12b of the winding stem 12, respectively, and in the normal hand movement state, the crown wheel 11 transmits the pointer correction transmission of the third wheel & pinion 10. The rotation is always transmitted by meshing with the gear 10a.

When the winding stem 12 is pulled out as shown in FIG. 4 and the winding stem 12 is set at the pointer correction position, the winding stem leading end shaft portion 12b is fitted into the fine hole portion 11a of the crown wheel 11, and the winding stem 12 and the crown stem 12a. The wheels 11 rotate simultaneously by friction coupling. By operating the winding stem 12 through rotation, the gear for transmitting the pointer correction is passed through the spiral wheel 11.
The rotating shaft 10b integrated with 10d is rotated, and the rotating shaft pinion 10
The rotation is transmitted from e to the minute hand wheel 13 to correct the pointer,
It is not necessary to use a small iron wheel as in the prior art. that time,
The third slip gear 10d receives the braking force of a braking device (not shown) built into the power train structure.
No. slip gear 10d and the sliding portion 10c of the rotary shaft 10b slip and prevent transmission of the pointer correction torque to the power train structure, so that normal pointer correction can be performed. As a matter of course, when the hands are corrected, the slip torque value of the slip mechanism provided in the third wheel & pinion 10 should be more than enough so that the hands can be surely corrected without slipping at the fitting portion between the winding stem 12 and the spiral wheel 11. The fitting torque between the tip shaft portion 12b of the winding stem 12 and the small hole portion 11a of the wheel & pinion 11 is guaranteed so that a high torque value can be transmitted to the rotating shaft 10b.

In order to prevent the rotation of the rotor (not shown) to the power side when the pointer is corrected, a slip mechanism has been conventionally provided in the minute hand wheel.In that case, the slip torque value is Approximately 4 to 8 g to prevent the pointer from being placed around due to overload of the train wheel or needle scratches
Although it is set to cm, the slip torque value when the third wheel is equipped with a slip mechanism is 4 to 4 in terms of the minute hand wheel.
It should be set to 8 gcm, so the minute hand wheel 13 and the third wheel are against the slip torque value of a normal minute hand wheel.
It can be reduced by the reduction ratio (number of teeth ratio) of the 10 rotary shaft pinion 10e. Therefore, the Tsuzumi car that rotates integrally with the winding stem 12
Since 11 is a structure for directly transmitting by meshing with the pointer correction transmission gear 10a provided on the rotary shaft 10b of the third wheel 10, the rotating torque value of the winding stem at the time of pointer correction becomes lower than that in the conventional case.

Further, with respect to the number of teeth of the spiral wheel 11, the pointer correction gear 10
By increasing the number of teeth of a, the rotating torque value of the winding stem can be further reduced.

Regarding the fact that the third wheel is provided with a slip mechanism, it is described in, for example, JP-A-55-175892 and JP-A-51-12160, but in the former case, a second gear and a third gear are used. The feature is the positional relationship in the plan view, and the latter is the direct engagement between the No. 2 gear and the Hino reverse wheel and the plane layout relationship with the hour wheel. The relationship with the pointer correction mechanism is specifically described. Absent.

〔The invention's effect〕

As is clear from the above examples, according to the present invention, 3
Because the slip mechanism is provided on the wheel & pinion, the slip torque value when the slip mechanism is provided on the minute hand wheel is reduced by 1 / (gear ratio) between the minute hand gear and the third wheel & pinion. Ten
It can be set as low as ~ 1/15, and the pointer correction transmission gear provided on the rotating shaft of the No. 3 wheel is directly rotated from the Tsuzumi wheel that rotates integrally with the winding stem to correct the pointer. Because of the structure, the rotating torque during the winding stem operation is low.

Therefore, when the pointer is corrected, the force applied to the teeth of the crown wheel when rotating the guide correction transmission gear becomes small,
In terms of strength, the Tsuzuki wheel can be easily made plastic.
Further, when fitting the winding true shaft and the spiral wheel at the time of correcting the pointer, even if the winding stem of the metal member and the spiral wheel of plastic molding are fitted, the fitting torque required for the function is sufficiently obtained. You can get it. Therefore, it is possible to make the Tsuru wheel, which is the backing part, plastic, and it is not necessary to make the winding stem shaft that fits with the Tsuru wheel into a corner shape, which makes it easier to process the winding stem. It is downed. Also, in the case of the Hino back wheel and the minute hand wheel, the 3rd slip torque is directly applied to the Hino back wheel due to the wheel train structure when the hands are corrected.
Since it does not add to the minute hand wheel, it can be easily made into plastic and the cost can be greatly reduced.

[Brief description of drawings]

1 and 2 are cross-sectional views of a main part of a conventional timepiece pointer correction device, and FIGS. 3 and 4 are main-part cross-sectional views of a timepiece pointer correction device according to an embodiment of the present invention. Is. 1, 12 …… Makishin, 2,11 …… Tsuzuki car, 10 …… No. 3 car,
10a …… Gear for transmitting the pointer correction, 10b …… Rotary shaft, 10c ……
Sliding part, 10d …… Gear, 10e …… Rotating shaft pinion, 6,14 ……
Hino back car, 7, 13 ... minute hand wheel.

Claims (1)

[Claims] 1. A rotatable and slidable winding stem, a crown wheel interlocked with the operation of the winding stem, and a position of a pointer attached to the wheel train by rotating the train wheel through the crown wheel. In the timepiece correction device for a timepiece, the train wheel includes at least a second hand wheel with a second hand, a minute hand wheel with a minute hand, and a third wheel for transmitting the rotation of the second hand wheel to the minute hand wheel. The No. 3 wheel has a rotary shaft integrally formed with plastic by a pinion meshing with the minute hand wheel, a pointer correction transmitting gear constantly meshing with the crown wheel, and a sliding portion, and slipping on the sliding portion. The Tsuzumi is formed of a third slip gear that fits and meshes with the second hand wheel, and the Tsumi is formed of plastic and has a narrow hole portion that fits with the winding stem. When set to the correction position, the winding stem is the fine wheel of the Tsuzuki wheel. Correction device of the timepiece, characterized in that the friction fit the part.