JP5131776B2 - Second hand support structure - Google Patents

Description

  The present invention relates to a second hand support structure for supporting a second hand of an analog timepiece.

  In general, a movement for driving a watch hand has a structure in which a second hand shaft for supporting a second hand, a minute hand pipe for supporting a minute hand, and an hour hand pipe for supporting an hour hand are each driven by a motor at a predetermined speed via a reduction mechanism. Yes. The second hand shaft is inserted through the minute hand pipe, and the minute hand pipe is inserted through the hour hand pipe. This type of structure that supports the pointer is also disclosed in US Pat.

Japanese Patent Laid-Open No. 10-48349 JP 2002-357672 A

  At present, when the technology of the resin material is improved, resin parts that are less expensive than metal are used as the components of the movement. However, for the parts whose strength is insufficient with resin, metal parts are used, and the second hand shaft is one of them.

  The second hand shaft is manufactured by turning a cylindrical material, and its base end portion is coupled to a resin second hand wheel. Although the shape of the second hand shaft is various, it usually has a flange-like portion as disclosed in the above-mentioned patent documents. The flange-shaped portion is a second hand shaft positioning means or a retaining means.

  Now, in the manufacture of such a second hand shaft, the diameter of the material is set according to the flange-shaped part, so that the diameter of the material is increased. In other words, there is a problem that the price of the material is high. Moreover, since the flange-shaped part is formed by turning, there is also a problem that the processing amount is large. The second hand shaft is an expensive part compared with a resin part, and it is considered that a structural contrivance is necessary to cope with such a problem.

  This invention is made | formed in view of this situation, The objective is to rationalize the support structure of a second hand, and to reduce the manufacturing cost of a second hand axis | shaft.

The invention described in claim 1 of the present application relates to a second hand support structure in which a metal second hand shaft that supports a second hand is coupled to a resin second hand wheel, and the second hand shaft is inserted into a minute hand pipe that supports the minute hand. The second hand shaft is a part formed by turning a cylindrical material, an intermediate portion whose diameter is equal to the diameter of the material, a base end portion whose diameter is smaller than the diameter of the material, and a diameter thereof Including a tip portion smaller than the diameter of the material, a boundary between the intermediate portion and the base end portion as a first step portion, and a boundary between the intermediate portion and the tip portion as a second step portion, and the second hand The vehicle is provided with a boss portion that extends inside the minute hand pipe, and the boss portion includes a hole portion into which the base end portion of the second hand shaft is inserted, and the base end portion of the second hand shaft is the boss shall be supported in part, to the minute hand pipe tip and the sliding rib-like sliding of said second hand shaft When the first step portion contacts the end surface of the boss portion, the second hand shaft is positioned with respect to the second hand wheel, and when the base end portion tries to escape from the hole portion, It is assumed that the second hand shaft is prevented from coming off when the two-step portion abuts against the sliding portion, and the total length L1 of the second hand shaft and the length L2 of the intermediate portion are:
(1/3) L1 ≦ L2
This is a second hand support structure having a configuration of

  According to the present invention, the manufacturing cost of the second hand shaft can be reduced.

1 is a side sectional view showing a timepiece according to an embodiment of the present invention. It is a front view which concerns on the Example of this invention and shows a movement. FIG. 4 is a side cross-sectional view showing the main parts of the dial and the movement according to the embodiment of the present invention. (A) is side surface sectional drawing which shows a second hand axis | shaft, a second hand wheel, and a minute hand pipe, and (b) is the A section enlarged view of (a). FIG. 3 is an exploded side sectional view showing a second hand shaft and a second hand wheel according to the embodiment of the present invention. (A) is side surface sectional drawing which shows a second hand axis | shaft, a second hand wheel, and a minute hand pipe, and (b) is the A section enlarged view of (a). It is a sectional side view showing a second hand shaft and a second hand wheel according to a conventional example. It is explanatory drawing which concerns on the Example of this invention, and a prior art example, and shows the turning site | part of the raw material of a second hand axis | shaft. (A) shows an embodiment of the present invention, and (b) shows a conventional example.

  Embodiments of the present invention will be described below with reference to the drawings. A timepiece 1 shown in FIG. 1 is configured by supporting a movement 300 for driving a second hand 311, a minute hand 312 and an hour hand 313 on the back surface of the dial 200. FIG. 2 is a front view showing the movement 300. FIG. 3 is a side sectional view showing a main part of the movement. FIG. 4A is a side cross-sectional view showing a second hand shaft, a second hand wheel, and a minute hand pipe, and FIG. 4B is an enlarged view of a portion A in FIG. FIG. 5 is an exploded side sectional view showing the second hand shaft and the second hand wheel.

  The movement 300 of this example includes a second hand shaft 321 for supporting the second hand 311, a minute hand pipe 322 for supporting the minute hand 312, an hour hand pipe 323 for supporting the hour hand 313, a central screw 330 through which the hour hand pipe 323 is inserted, and And a flat case body 340 to be held. The second hand shaft 321 is inserted through the minute hand pipe 322, and the minute hand pipe 322 is inserted through the hour hand pipe 323. That is, the minute hand pipe 322, the hour hand pipe 323, and the center screw 330 are provided concentrically around the second hand shaft 321.

  Further, the pinion provided at the proximal end portion of the minute hand pipe 322 is connected to the minute wheel 325, and the hour hand wheel 323a provided at the proximal end portion of the hour hand pipe 323 is connected to the pinion of the minute wheel 325. Has been.

  A first motor and a second motor (not shown) are provided inside the case body 340, and a train wheel connected to the first motor is connected to a second hand wheel 324 provided at the base end 321 b of the second hand shaft 321. It is connected. Further, a train wheel connected to the second motor is connected to a minute hand wheel 322 a provided at a proximal end portion of the minute hand pipe 322. The second hand shaft 321 is rotationally driven by the first motor at a predetermined speed, and the hour hand pipe 323 and the minute hand pipe 322 are each rotationally driven by the second motor at a predetermined speed.

  The movement 300 is used for a radio-controlled timepiece that receives a standard time radio wave and corrects its display time. The case body 340 is provided with an antenna 350 that receives standard time radio waves, and a circuit board 360 having a predetermined shape on which circuits for controlling each motor and reception operation are mounted. The antenna 350 is provided on the upper portion of the case body 340, and the circuit board 360 is provided on the front surface of the case body 340 by screws. An opening 361 that penetrates through the central screw 330 is provided at a point of the circuit board 360. A battery box 370 serving as a power source for the movement 300 is provided below the case body 340.

  The dial plate 200 is provided with an insertion hole 210 through which the central screw 330 is inserted. The movement 300 is supported by the dial plate 200 by inserting a central screw 330 into the insertion hole 210 from the back side of the dial plate 200 and screwing a central nut 380 into the central screw 330 from the front side of the dial plate 200.

  Next, the second hand support structure of this example will be described. In this example, the second hand shaft 321 made of metal is coupled to the second hand wheel 324 made of resin, and the second hand shaft 321 is inserted through the minute hand pipe 322. The minute hand pipe 322 and the minute hand wheel 322a are integrally formed resin parts. Similarly, the hour hand pipe 323 and the hour hand wheel 323a are also resin parts that are integrally molded. On the other hand, the second hand shaft 321 is a metal part because it is necessary to ensure its strength, and is connected to a second hand wheel 324 which is a resin part.

  The second hand shaft 321 is a part formed by turning a cylindrical material, an intermediate portion 321a having a diameter equal to the material diameter, a base end portion 321b having a diameter smaller than the material diameter, and a diameter thereof. Has a tip 321c smaller than the diameter of the material. The boundary between the intermediate part 321a and the base end part 321b is the first step part 321d, and the boundary between the intermediate part 321a and the tip part 321c is the second step part 321e.

  The second hand wheel 324 is provided with a boss portion 324a having a predetermined shape. The boss 324a is provided with a hole 324b into which the proximal end 321b of the second hand shaft 321 is inserted. That is, the second hand shaft 321 is coupled to the second hand wheel 324 by press-fitting the base end 321b into the hole 324b using a jig. Alternatively, the second hand wheel 324 may be integrally insert-molded with the second hand shaft 321 at the time of injection molding.

  The minute hand pipe 322 is provided with a rib-like sliding portion 322b that slides with the tip portion 321c of the second hand shaft 321 and an auxiliary sliding portion 322c that slides with the outer periphery of the boss portion 324a. The auxiliary sliding portion 322c comes into contact with the second hand shaft 321 when the second hand shaft 321 is shaken in rotation, thereby correcting the rotation.

  The second step shaft 321 is positioned with respect to the second hand wheel 324 by the first step portion 321d coming into contact with the end surface of the boss portion 324a.

  Further, when the base end portion 321b of the second hand shaft 321 is about to be removed from the hole portion 324b, the second step portion 321e abuts against the sliding portion 322b, so that the second hand shaft 321 is prevented from coming off. Actually, it is extremely rare for the base end portion 321b of the second hand shaft 321 to slip out of the hole portion 324b, but if the second hand shaft 321 falls off due to some unexpected situation, it is difficult to repair it. At this time, if the base end 321b is not completely detached from the hole 324b, the second hand shaft 321 can be restored by pushing it back.

  In the case of this example, the total length L1 of the second hand shaft and the length L2 of the intermediate portion are set to have a relationship of (1/3) L1 ≦ L2. According to such a configuration, the support structure of the second hand 311 can be rationalized and the manufacturing cost of the second hand shaft 321 can be reduced. The concept will be described below.

  As described above, the second hand shaft 321 of this example is a flange-less metal part, which has a very advantageous configuration in manufacturing.

  6 and 7 show an example in the case where a flange-like portion is provided on the second hand shaft 321. FIG. Parts common to this example are denoted by the same reference numerals as in this example. As shown in these drawings, the flange-shaped portion 321a functionally corresponds to the intermediate portion of the present example described above. However, the length L2 of the flange-shaped portion 321 is extremely shorter than the total length L1 of the second hand shaft 321.

  Similarly to the above-described example, when the base end portion 321b tries to escape from the hole portion 324b, the second step portion 321e abuts against the sliding portion 322b of the minute hand pipe 322, thereby preventing the second hand shaft 321 from coming off. It is supposed to be. However, due to the positional relationship of the second step portion 321e, the position of the sliding portion 322b is necessarily away from the second hand 311 side. That is, in order to stably support the second hand 311, it is advantageous that the position of the sliding portion 322 b is closer to the second hand 311 side. However, in the examples shown in these drawings, the distance from the second hand 311 becomes longer. It is necessary to set the diameter of the part in contact with the moving part 322b to be relatively large.

Therefore, considering the manufacturing by turning in consideration of these conditions, as shown in FIG. 8, in the case of this example described above, the diameter D1 of the material is larger than the diameter D2 of the material in the case of the examples shown in these drawings. There is an advantage that the processing amount is small and the processing amount is small. The total length L1 of the second hand shaft 321 and the length L2 of the intermediate portion are (1/3) L1 ≦ L2 from the viewpoint of ensuring the balance of the support structure of the second hand 311 and the ease of turning.
This is the reason why the relationship is set. More preferably, the relationship of (1/2) L1 ≦ L2 is set.

  As described above, according to the second hand support structure of this example, a significant effect of reducing the manufacturing cost of the second hand shaft can be achieved by rationalizing the second hand support structure. In addition, it is needless to say that the configuration of each part in the present example can be appropriately changed in design within the technical scope described in the claims, and is not limited to that illustrated in the drawings.

  The second hand support structure of the present invention can be suitably used as a structure constituting a movement of an analog timepiece.

DESCRIPTION OF SYMBOLS 1 Clock 200 Dial 210 Insertion hole 300 Movement 311 Second hand 312 Minute hand 313 Hour hand 321 Second hand shaft 321a Intermediate part 321b Base end part 321c Front end part 321d First stage part 321e Second stage part 322 Minute hand pipe 322a Minute hand wheel 322b Sliding part 322b Auxiliary sliding part 323 Hour hand pipe 323a Hour hand wheel 324 Second hand wheel 324a Boss part 324b Hole part 325 Sun wheel 330 Center screw 340 Case body 350 Antenna 360 Circuit board 370 Battery box 380 Center nut

Claims (1)

In the second hand support structure in which the metal second hand shaft supporting the second hand is coupled to the resin second hand wheel and the second hand shaft is inserted through the minute hand pipe supporting the minute hand,
The second hand shaft is a part formed by turning a cylindrical material, an intermediate portion whose diameter is equal to the diameter of the material, a base end portion whose diameter is smaller than the diameter of the material, and a diameter thereof A tip portion smaller than the diameter of the material, a boundary between the intermediate portion and the base end portion is a first step portion, a boundary between the intermediate portion and the tip portion is a second step portion,
The second hand wheel is provided with a boss portion extending inside the minute hand pipe ,
The boss portion includes a hole portion into which the proximal end portion of the second hand shaft is inserted, and the proximal end portion of the second hand shaft is supported by the boss portion,
The minute hand pipe is provided with a rib-shaped sliding portion that slides with the tip of the second hand shaft,
When the first step portion contacts the end surface of the boss portion, the second hand shaft is positioned with respect to the second hand wheel,
When the base end portion tries to escape from the hole portion, the second step shaft abuts against the sliding portion, so that the second hand shaft is prevented from coming off,
The total length L1 of the second hand shaft and the length L2 of the intermediate portion are:
(1/3) L1 ≦ L2
A second hand support structure characterized by the following relationship.

Images