JPH0452705Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a timepiece train structure using a train train bridge made of plastic resin.

[Prior art]

In the past, plastic materials had extremely low molding costs, but they had inferior dimensional accuracy and were considered to be extremely weak compared to metals.However, recent technological research and development has resulted in superior dimensional accuracy and strength. Even though it is not as strong as metal, its strength has been increased. Against this background, watches have been released in recent years that aim to reduce costs by making extensive use of plastic resin for the main plate, train wheel bridge, and number wheel. However, it is still considered impossible to use plastic in parts where external human forces are applied.

The wheel train structure of a conventional timepiece is shown in Figure 1. 1 is the main plate, 2 is the second wheel guided by a central pipe driven into the main plate 1, 2a is the second gear, and 2b is the fourth wheel riding surface. 3 is the third wheel, and 3a is the gear of the third wheel & pinion 3. 4 is the fourth wheel indicated by the center wheel 2 and the gear train bridge. 4a and 4b are a fourth gear and a fourth pinion, which are integrally molded and pressed in from plastic resin, respectively. 4c is the second hand pushing part, 4d is the fourth wheel & pinion 4
The upper part of the handle is shown. Reference numeral 5 denotes a train wheel bearing whose bearing portion is also integrally molded with plastic resin. 6a is the fifth gear.

In Fig. 1, when attaching the second hand, pressure is applied to the second hand attaching part 4c to push the hand in. However, since the gear train bridge 5 and the fourth pinion part 4b are made of plastic, the pointer attachment is made of hardened steel or the like. It is necessary to hold the fourth upper handle part 4d on a hard table. However, in reality, it is generally not done to attach the needles on a hard table made of steel, etc., as it increases the number of steps. There is a problem that the row support 5 may be damaged. This is because the surface compressive stress at the fourth kana portion becomes extremely high due to the needle pushing force. Similarly, when the minute hand is pushed in, pressure is applied to the fourth wheel & pinion 4 through the fourth wheel & pinion riding surface 2b of the second wheel & pinion 2, causing a similar problem. Furthermore, if the plastic resin-molded gear train bridge 5 is supported by the fourth pinion 4b as shown in Fig. 1, the contact surface on the gear train bridge side will be damaged by the tips of the pinion teeth of the fourth pinion 4b. As a result, there are some problems that can cause problems. Furthermore, since the fourth pinion 4b is above the fourth gear 4a, the third gear 3a
Also, there was a problem that the handle erectness was deteriorated in assembling the fifth gear 6a.

〔the purpose〕

The present invention is intended to solve these problems, and its purpose is to make it possible to use plastic for the train wheel bridge and fourth wheel, thereby significantly reducing the cost of parts. Another object of the present invention is to provide a gear train structure that eliminates damage to the gear train bridge and fourth wheel due to needle pushing.

〔overview〕

The wheel train structure of a watch according to the present invention includes a second wheel and a second wheel pivotally supported on a main plate, and a fourth wheel and a second wheel rotatably supported by a through hole in the second wheel and a train wheel bridge. , the gear train bridge is made of plastic resin, and a bearing surface of the fourth wheel that protrudes toward the main plate is formed on the bearing portion of the fourth wheel; A fourth gear is disposed on the gear train receiving side, and when the needle is pushed in, the receiving surface of the gear train receiver directly receives the surface of the fourth gear on the gear train receiving side.

〔Example〕

Hereinafter, the present invention will be described in detail based on examples. An embodiment of the present invention is shown in FIG. 1 is the main plate, 2 is the second wheel, and 3 is the third wheel. 4 is a fourth wheel, and 4a and 4b are a metal fourth gear and a fourth pinion, respectively. Unlike the conventional example, the contact on the gear train receiving side is made on the top surface of the fourth gear 4a.
Below that is the fourth pinion 4b, which meshes with the third pinion 3a. The fourth gear 4a is pushed into the fourth wheel 4 and has a smooth upper surface. Reference numeral 5 denotes a gear train bridge, and 5a indicates a bearing surface formed protruding from the main plate side of the gear train bridge with which the upper surface of the fourth gear 4a comes into contact. 6a
The fifth bearing surface 4a is provided at a position facing the vicinity of the outer periphery of the fourth pinion, and the side surface is sloped toward the bearing hole to avoid contact with the fourth wheel.

In FIG. 2, when attaching the second hand, pressure is applied to the second hand attaching part 4c to push the second hand in. However, as in this embodiment, the upper surface of the fourth gear 4a is directly pressed against the receiving surface 5a of the gear train bridge. Unlike the conventional method in which the fourth pinion is brought into pressure contact with the gear train bearing surface, it is possible to suppress the surface compressive stress as small as possible, and the fifth and fourth pinion 4b can be prevented from being deformed or damaged. Next, when assembling the movement, in order to assemble the fourth wheel 4 after assembling the fifth and third wheels 3, the fourth gear 4a
The third gear 3a and the fifth gear 6a can be held down from above, preventing the third gear 3 and the fifth wheel from collapsing, and improving the handle erectness when the gear train bridge 5 is assembled. . Moreover, similar effects can be obtained even if the fourth gear 4a is made of plastic resin.

〔effect〕

As described above, when the fourth gear and pinion are made of metal, it is necessary to form a shoulder portion into which the gear is driven into the true of the fourth wheel.

Therefore, since the shoulder of the fourth wheel true protrudes in the direction of the train wheel bridge, it may damage the plastic train wheel bridge when pushing the pointer in, or the plastic train wheel bridge may be scraped during operation, causing damage to the gears. There is a problem of stopping.

However, as in the present invention, by providing a slope on the side surface of the bearing surface so that the shoulder of the fourth wheel true does not come into contact with the slope of the train bridge, it is possible to prevent the gear from stopping. be.

Furthermore, by arranging the shoulder of the fourth wheel in a space formed in the slope of the receiving surface so that it does not come into contact with the slope of the receiving surface, the watch can be made thinner.

Furthermore, since the fourth wheel can be incorporated using the slope portion as a guide, the work of assembling the fourth wheel can be facilitated.

Next, when pushing the needle into the fourth wheel, the flat surface of the gear train receiver side of the fourth gear is directly received by the receiving surface of the gear train receiver, which eliminates the need to push the needle into the gear train receiver with the fourth pinion. Unlike pressure contact, surface compressive stress can be kept to a minimum, eliminating the problem of damage to the gear train bridge.

Furthermore, since the receiving surface is located at a position opposite to the vicinity of the outer periphery of the fourth pinion, there is no problem of bending of the fourth gear when the pointer is pushed in.

[Brief explanation of the drawing]

FIG. 1 is a diagram of the wheel train structure of a conventional timepiece, and FIG. 2 is a sectional view showing an example of the wheel train structure of the timepiece according to the present invention. 1...Main plate, 2...Second wheel, 3...Third wheel, 4
...4th wheel, 5...gear train receiver.

Claims (1)

[Scope of Claim for Utility Model Registration] A wheel train structure for a timepiece comprising a second wheel pivotally supported on a main plate, and a fourth wheel pivotally supported by a through hole of the second wheel and a train wheel bridge, The fourth wheel has a fourth pinion on the side that engages with the second wheel, and a thin plate-like fourth gear on the gear train receiving side, and the fourth pinion and the fourth pinion are made of metal. The gear train bridge is made of plastic resin, and has a bearing hole and a bearing surface protruding toward the main plate at a position facing the outer circumferential portion of the fourth pinion, and the bearing surface is The side surface is sloped toward the bearing hole so as not to contact the shoulder of the fourth wheel stem, and when the needle is pushed into the fourth wheel, the ring of the fourth gear is formed on the receiving surface of the gear train bridge. A watch train structure characterized by being directly received by the flat surface of the train receiving side.