US3744237A

US3744237A - Indicating wheel driving mechanisms of timepieces

Info

Publication number: US3744237A
Application number: US00230572A
Authority: US
Inventors: T Muto
Original assignee: Citizen Watch Co Ltd
Current assignee: Citizen Watch Co Ltd
Priority date: 1971-03-04
Filing date: 1972-03-01
Publication date: 1973-07-10
Anticipated expiration: 1990-07-10
Also published as: JPS4711263U; JPS5151647Y2

Abstract

In an indicating wheel driving mechanism of a timepiece, comprising an indicating wheel driving wheel and an indicating wheel driving wheel finger for driving said driving wheel, a slot is formed in the driving wheel to define a resilient portion and said indicating wheel driving wheel finger is formed integrally with said resilient portion at a location adjacent the free end thereof, and further means for restricting the degree of bending of said resilient portion is provided, whereby when the driving wheel rotates in the normal direction, the resilient portion is prevented from bending and an indicating wheel is driven by said finger, whereas when the driving wheel rotates in the reverse direction, the resilient portion is allowed to bend and the finger is relieved from restraint by the indicating wheel, providing for rotation of said driving wheel.

Description

11 3,744,237 [45] July 10,1973

[ INDICATING WHEEL DRIVING MECHANISMS OF TIMEPIECES [75] Inventor: Teruo Muto, Kita-ku, Tokyo, Japan [73] Assignee: Citizen Watch Co., Ltd., Tokyo,

Japan [22] Filed: Mar. 1, 1972 [21] App]. No.: 230,572

[30] Foreign Application Priority Data Mar. 4, 1971 Japan 46/13861 [52] US. Cl. 58/58 [51] Int. Cl. ..L G04b 19/24 [58] Field of Search, 58/4, 5, 58, 63

[56] References Cited UNITED STATES PATENTS 3,352,103 11/1967 Giger 58/58 3,177,647 4/1965 Meyer 58/58 FOREIGN PATENTS OR APPLICATIONS 420,996 3/ 1967 Switzerland 58/58 480,674 12/1969 Switzerland 515/58 Primary Examiner--George H. Miller, Jr. Att0rneyS. Delvalle Goldsmith, Lester Horwitz et a1.

[57] ABSTRACT In an indicating wheel driving mechanism of a timepiece, comprising an indicating wheel driving wheel and an indicating wheel driving wheel finger for driving said driving wheel, a slot is formed in the driving wheel to define a resilient portion and said indicating wheel driving wheel finger is formed integrally with said resilient portion at a location adjacent the free end thereof, and further means for restricting the degree of bending of said resilient portion is provided, whereby when the driving wheel rotates in the normal direction, the resilient portion is prevented from bending and an indicating wheel is driven by said finger, whereas when the driving wheel rotates in the reverse direction, the resilient portion is allowed to bend andthe finger is relieved from restraint by the indicating wheel, providing for rotation of said driving wheel.

9 Claims, 6 Drawing Figures INDICATING WHEEL DRIVING MECHANISMS OF TIMEPIECES This invention relates to a driving mechanism in a timepiece of the type having an indicating wheel or wheels such as a date dial, by which said indicating wheel is driven to change the indication thereof.

Conventional indicating wheel driving mechanisms of the type described include a type which comprises a driving wheel and a finger for driving said driving wheel fixed on a gear, and a type which comprises a driving wheel, a finger for driving said driving wheel rotatably mounted on a gear and spring yieldably holding said finger in engagement with said driving wheel in such a manner that said driving wheel may be rotatable at the time of reverse rotation of the indicating wheel or quick correction of indication. However, the former type has the disadvantage that, when the finger is in engagement with the tooth of the indicating wheel at the time of reverse rotation or quick correction of indication, it cannot be relieved from restraint by the indicating wheel, with the result that the indication cannot be changed sequentially or the indicating wheel cannot be driven, and the application of unreasonable force to the driving mechanism tends to result in breakage of the mechanism. The latter type is free of the abovedescribed disadvantage but suffers such disadvantage that the mechanism is complicated and includes an undesirably large number of component parts such as the finger, the spring, the pivot pin for the finger, etc. which are very small in size and'hence difficult to fabricate and assemble. Furthermore, in both types the gear and finger are substantially large in thickness and occupy a considerably large space, it being impossible to reduce said thicknesses even when it is most desirable to arrange the teeth of the indicating wheel and driving wheel on the same level. An additional disadvantage of these prior art driving mechanisms is that the clearance between the pivot pin of the finger, provided on the gear and a hole for receiving said pin formed in said finger must be controlled with high precision.

The present invention contemplates the elimination of such disadvantages of the prior art mechanisms. Namely, the object of the invention is to provide an indicating wheel driving mechanism of a timepiece, which satisfies the following requirements:

a. The indicating wheel driving wheel finger can be smoothly relieved from the indicating wheel at the time of reverse rotation of the driving wheel and quick correction of indication by a quick correction mechanism,

b. The construction is simple.

The above object can be attained by an indicating wheel driving mechanism which comprises an indicating wheel driving wheel having a slot formed therein to define an integral resilient portion, an indicating wheel driving wheel finger formed integrally with said driving wheel at a location adjacent the free end of said resilient portion for engagement with the teeth of indicating wheel and means for restricting the degree of bending of said resilient portion, said bending restricting means preventing bending of said resilient portion during rotation of said driving wheel in the normal direction but permitting the bending of said resilient portion during reverse rotation of said driving wheel so that said driving wheel finger may be relieved from restraint by the teeth of said indicating wheel.

The present invention will be described by way of example hereunder with reference to the accompanying drawings. In the drawings,

FIG. 1 is a plan view showing the essential portion of a first embodiment of the indicating wheel driving mechanism according to the present invention, as applied to a calender timepiece for driving a date dial, a dial and a date dial guard being not shown for the sake of simplicity;

FIG. 2 is a sectional view taken on the line IIII of FIG. 1;

FIG. 3 is a plan view similar to FIG. 1 but showing the essential portion of a second embodiment of the invention;

FIG. 4 is a sectional view taken on the line IVIV of FIG. 3;

FIG. 5 is a plan view similar to FIGS. 1 and 3 but showing the essential portion of a third embodiment of the invention; and

FIG. 6 is a sectional view taken on the line VI-VI of FIG. 5.

With reference to the drawings and first to FIGS. 1 and 2, a driving wheel 3 loosely rotatably mounted on a pin 1a on a plate 1 has a resilient portion 3c defined by a substantially elongated slot 3b formed therein. The driving wheel 3 is formed from a singular planar gear blank and has teeth 3d continuously formed along the peripheral edge thereof including the resilient portion 3c, and the tooth 3e located adjacent the free end of said resilient portion 30 is made longer than the remaining teeth 3d to constitute an indicating wheel driving wheel finger. The tooth 3e otherwise has the same function as the teeth 3d. Bending

check portions

3f, 3g are provided at the free end of the resilient portion 3c and the confronting portion of the main portion or body 3a of the driving wheel 3 respectively, as means for restricting the degree of bending of said resilient portion 30, which abut against each other during rotation of the driving wheel 3 in the normal direction. On an hour wheel 4 is mounted an intermediate wheel 5 which is meshing with the driving wheel 3. An indicating wheel or date dial 2 has teeth 2a and is arranged such tht said teeth 2a may be engaged by the indicating wheel driving wheel finger 3e of the driving wheel 3. Reference numeral 6, in the embodiment shown, designates a date dial guard which in this case is an indicating wheel guard, 7 a dial, 8 a dial jumper and 9 a cannon pinion.

The driving mechanism constructed as described above operates in the following manner: Namely,'when it is desired to drive the indicating wheel 2, the driving wheel 3 is rotated counterclockwise by the intermediate wheel 5 rotating in a clockwise direction and the indicating wheel driving wheel finger Se is brought into engagement with the tooth 2a of indicating wheel 2. As the indicating wheel driving wheel finger 3e moves further in engagement with the tooth 2a, the resilient portion 3c is bent more and more, and finally the bending check portion 3f is brought into abutment with a surface of the bending check portion 3g of the main portion 3a of driving wheel 3. Therefore, the resilient portion 3c is prevented from further bending and causes the indicating wheel 2 to be rotated one tooth in a counterclockwise direction by the indicating wheel driving wheel finger 32 which can no longer be displaced either radially or circumferentially relative to the main gear body 3a. Thus, the indication, such as date, on the indicating wheel is changed.

When it is desired to further change the indication to the next date, a stern (not shown) of the timepiece is rotated in the opposite direction to the former direction, whereby the intermediate wheel is rotated in a counterclockwise direction, the driving wheel 3 is rotated in a clockwise direction and the indicating wheel driving wheel finger 3e engages the tooth 2a of indicating wheel 2. Therefore, the resilient portion 30 of the driving wheel 3 is bent more and more as said driving wheel 3 rotates and finally the indicating wheel driving wheel finger 3e jumps over the tooth 2a of indicating wheel 2. During this period, the indicating wheel 2 is held stationary in its position.

Now, when the rotating direction of the stem is changed, the mechanism operates in the same manner as in the case of clockwise rotation of the intermediate wheel 5 described previously. Namely, the intermediate wheel 5 rotates clockwise causing the driving wheel 3 to rotate in a counterclockwise direction, and the indicating wheel driving wheel finger Se is brought into engagement with the tooth 2a of indicating wheel 2 and drives said indicating wheel one tooth. Thus, the indication is changed. Quick correction of date on the indicating wheel 2 can be achieved in this manner.

The indicating wheel driving wheel finger 3e will not be broken even if it is at the position of the teeth 2a of indicating wheel 2 at, the time of quick correction of date by means of a quick correction mechanism (not shown), since it is relieved from restraint by the indicating wheel, due to the resiliency of the resilient portion 3c.

The embodiment described above is advantageous in that, since the bending check portions for restricting the degree of bending of the resilient portion are provided on the driving wheel proper, no additional parts need to be provided for the same purpose.

The second embodiment of the invention will be described with reference to FIGS. 3 and 4 in which parts corresponding to those of the first embodiment are indicated by same numerals with 100 added thereto. in H08. 3 and 4, reference numeral 101 designates a plate having a depression 101b, 102 an indicating wheel, for example, date dial having teeth 102a, and 103 a driving wheel loosely rotatably mounted on a pin 101a on the plate 101 and having a resilient portion 1030, defined by a substantially elongated slot 103b, and an indicating wheel driving wheel finger 103s adjacent the free end of said resilient portion for engagement with the teeth 102a of said indicating wheel 102, similar to the driving wheel of the first embodiment. Reference numeral 105 designates an intermediate wheel mounted on an hour wheel 104 and meshing with the teeth 103d of the driving wheel 103. In this embodiment, the depression 1011b formed in the plate 101 is so shaped that the wall of said depression will restrict the degree of bending of the resilient portion 103cdriving wheel 103. j

in the construction described above, when the intermediate wheel 105 rotates in the normal direction, the driving wheel 103 is rotated and its finger 103a is brought into abutment against the tooth 102a of the indicating wheel 102. As the driving wheel 103 further rotates, the resilient portion 103a bends but the bending is restricted by a stop surface on the wall 1010 of the depression 101b formed in the plate 101 and said finger 103e causes the indicating wheel 102 to rotate. In the mechanism according to this embodiment, the

component parts operates in the same manner as those in the first embodiment at the time of reverse rotation of the driving wheel 103 and quick correction of indication by a quick correction mechanism (not shown).

According to this embodiment, the following advantages can be obtained:

a. Since the driving wheel and indicating wheel are arranged not in the same plane, less limitation is imposed on the shape of driving wheel, which facilitates the design of the timepiece mechanism. For instance, when a date dial in the form of a ring having internal teeth, like that of the first or second embodiment is employed, a driving wheel of a large diameter is required for driving said date dial by reason of reduction gear ratio, but according to this embodiment such a large diameter driving wheel can be arranged more easily than in the first embodiment, as it can be disposed beneath the indicating wheel.

b. Since the wall of the depression in the plate is utilized for restricting the degree of bending of the resilient portion, no additional parts are required for the same purpose.

A third embodiment of the invention is shown in FIGS. 5 and 6 in which parts generally corresponding to those of the first embodiment are indicated by same numerals with 200 added thereto. in FIGS. 5 and 6, reference numeral 201 designates a plate and 202 an indicating wheel for indicating date having teeth 202a. The teeth 202a of the indicating wheel 202 are held down by a date dial guard 206 secured to the plate 201 by means of a screw 207. The date dial guard 206 has an integral date jumper 206a at one end thereof and also has a cam shaped recess 206b formed therein at a location above a driving wheel to be described later. Reference numeral 203 indicates the driving wheel which is loosely rotatably mounted on a pin 201a on the plate 201 and has a resilient portion 203e, defined by a substantially elongated slot 203b, and teeth 203d continuously formed along the peripheral edge thereof, one of said teeth 203d which is located adjacent the free end of said resilient portion 203c being made longer than the remaining teeth to constitute an indicating wheel driving wheel finger 203e, for driving the indicating wheel 202, similar to the driving wheel of the first or second embodiment described above. In this embodiment, however, a projection 203f is provided on the upper surface of the resilient portion 2030 of driving wheel 203 at a location adjacent the free end of said resilient portion 203C, and this projection 203 f extends into engagement with the surface of the cam shaped recess 206!) of date dial guard 206. On the other hand, the driving wheel 203 is meshing with an intermediate wheel 205, mounted on an hour wheel 204, to be driven thereby.

[n the construction described above, when the driving wheel 203 is rotated in the normal or reverse direction, the degree of engagement between the indicating wheel driving wheel finger 203e and the tooth 202a of indicating wheel 202 can be adjusted by the co-action of the projection 203f on the resilient portion 201% and the cam shaped recess 206b, so that the indicating wheel 202 can be driven exactly. Furthermore, quick correction of indication by a quick correction mechanism (not shown) can be smoothly achieved even if the finger 203e is at the position of the teeth 202a of indi cating wheel 202, because the finger 203e is relieved from restraint by the indicating wheel 202, due to the resiliency of the resilient portion 203c.

According to this embodiment, the following advantage can be obtained: Namely, since the degree of bending of the resilient portion and the degree of engagement between the indicating wheel driving wheel finger and the tooth of indicating wheel can be adjusted by the cam shaped recess, the indicating wheel can be positively driven.

In summation, the driving mechanism of the invention has the following advantages over the prior art mechanisms:

a. The driving wheel, because of its simple shape, can be integrally molded of a synthetic resin material and, therefore, is economical and not required to be assembled, as compared with that in the prior art mechanism which is composed of a plurality of parts.

b. The resilient portion can be made highly flexible as it can be made considerably long as required. Therefore, it passes over the tooth of indicating wheel very easily, without exerting an unnecessary reaction on the indicating wheel, and there is no fear of the indicating wheel being displaced from its set position. Consequently, the strength of the jumper can be decreased and hence the indicating wheel can be driven with a minimum load.

c. The bending degree of the resilient portion is restricted by the bending check means, so that in no cases will the indicating wheel driving wheel finger be moved off the position to engage the tooth of indicating wheel during rotation of said indicating wheel in the normal direction and positive driving of the indicating wheel is ensured.

What is claimed is:

1. An indicating wheel driving mechanism in a time piece, comprising an indicating wheel driving wheel having a slot formed therein to define an integral resilient portion, an indicating wheel driving wheel finger formed integrally with said driving wheel at a location adjacent the free end of said resilient portion for engagement with the teeth of indicating wheel, and means for restricting the degree of bending of said resilient portion, said bending restricting means preventing bending of said resilient portion during rotation of said driving wheel in the normal direction, but permitting the bending of said resilient portion during reverse rotation of said driving wheel so that said indicating wheel driving wheel finger may be relieved from restraint by the teeth of said indicating wheel, said means for restricting the degree of bending consisting of the wall of a depression formed in a plate of the timepiece and said resilient portion being brought into abutment against said wall, whereby the degree of bending of said resilient portion is restricted.

, 2. An indicating wheel driving mechanism in a timepiece, comprising an indicating wheel driving wheel having a slot formed therein to define an integral resilient portion, an indicating wheel driving wheel finger formed integrally with said driving wheel at a location adjacent the free end of said resilient portion for engagement with the teeth of indicating wheel, and means for restricting the degree of bending of said resilient portion, said bending restricting means preventing bending of said resilient portion during rotation of said driving wheel in the normal direction, but permitting the bending of said resilient portion during reverse rotation of said driving wheel so that said indicating wheel driving wheel finger may be relieved from restraint by the teeth of said indicating wheel, said means for restricting the degree of bending consisting of a projection formed on the upper surface of said resilient portion integrally therewith and a driving wheel guard having a cam shaped recess formed therein, and said projection being brought into abutment against the edge of said cam shaped recess, whereby the degree of bending of said resilient portion is restricted.

3. In a timepiece having an indicator and a driving mechanism for advancing the indicator in one direction between a plurality of indicating positions, a driving wheel comprising a planar gear body having a periphery formed with a plurality of teeth in meshing engagement with said driving mechanism, said gear body being provided with an elongated slot to form a resilient peripheral portion of said gear body having a deflectable end from which one of said teeth project, a driving formation projecting from said deflectable end of the resilient portion and engageable with the indicator, and deflection limiting means for preventing radial and circumferential displacement of said driving formation relative to the gear body in response to engagement thereof with the indicator in said one direction only.

4. The combination of claim 3 wherein said driving formation is a radial extension of said one of the teeth at the deflectable end of the resilient portion of the gear body.

5. The combination of claim 4 wherein said deflection limiting means includes a projection on the resilient portion adjacent the deflectable end and a stop surface engageable by the projection in response to displacement of the driving formation when engaging the indicator.

6. The combination of claim 5 wherein said stop surface is on a fixed cam member.

7. The combination of claim 3 wherein said deflection limiting means includes a projection on the resilient portion adjacent the deflectable end and a stop surface engageable by the projection in response to displacement of the driving formation wihen engaging the indicator.

8. The combination of claim 7 wherein said stop surface is formed on a check portion of the gear body.

9. The combination of claim 8 wherein said driving formation is a radial extension of said one of the teeth at the deflectable end of the resilient portion of the gear body.

Claims

1. An indicating wheel driving mechanism in a timepiece, comprising an indicating wheel driving wheel having a slot formed therein to define an integral resilient portion, an indicating wheel driving wheel finger formed integrally with said driving wheel at a location adjacent the free end of said resilient portion for engagement with the teeth of indicating wheel, and means for restricting the degree of bending of said resilient portion, said bending restricting means preventing bending of said resilient portion during rotation of said driving wheel in the normal direction, but permitting the bending of said resilient portion during reverse rotation of said driving wheel so that said indicating wheel driving wheel finger may be relieved from restraint by the teeth of said indicating wheel, said means for restricting the degree of bending consisting of the wall of a depression formed in a plate of the timepiece and said resilient portion being brought into abutment against said wall, whereby the degree of bending of said resilient portion is restricted.

2. An indicating wheel driving mechanism in a timepiece, comprising an indicating wheel driving wheel having a slot formed therein to define an integral resilient portion, an indicating wheel driving wheel finger formed integrally with said driving wheel at a location adjacent the free end of said resilient portion for engagement with the teeth of indicating wheel, and means for restricting the degree of bending of said resilient portion, said bending restricting means preventing bending of said resilient portion during rotation of said driving wheel in the normal direction, but permitting the bending of said resilient portion during reverse rotation of said driving wheel so that said indicating wheel driving wheel finger may be relieved from restraint by the teeth of said indicating wheel, said means for restricting the degree of bending consisting of a projection formed on the upper surface of said resilient portion integrally therewith and a driving wheel guard having a cam shaped recess formed therein, and said projection being brought into abutment against the edge of said cam shaped recess, whereby the degree of bending of said resilient portion is restricted.

7. The combination of claim 3 wherein said deflection limiting means includes a projection on the resilient portion adjacent the deflectable end and a stop surface engageable by the projection in response to displacement of the driving formation when engaging the indicator.