Provided is a timepiece including a decorative body that operates stably and intricately. The timepiece includes: a main plate provided with external teeth extending in a circular-arc shape with a central axis O as a center; a rotating plate rotatable around the central axis O with respect to the main plate; a first gear rotatably supported on the rotating plate; a transmission gear train rotatably supported on the rotating plate, meshing with the external teeth and the first gear, and configured to transmit, to the first gear, rotation of the main plate with respect to the rotating plate; and a first front decorative body non-rotatably connected to the first gear and displaceable with respect to the rotating plate.

RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No. 2022-005683, filed on Jan. 18, 2022, the entire content of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a timepiece.

2. Description of the Related Art

There is a gimmick clock moving a decorative body (refer to, for example, JP-A-2014-215093 and Japanese Patent No. 3691946). The gimmick clock described in JP-A-2014-215093 includes a main plate, a rotating plate rotatable relative to the main plate, a gear rotatably supported on the rotating plate, and a decorative body connected to the gear. The gear is rotatably supported by the rotating plate, and meshes with an external tooth part or an internal tooth part of the main plate to rotate while revolving. The gimmick clock described in Japanese Patent No. 3691946 includes a drive device that drives an annular rotating decorative plate. A tooth part that meshes with a gear driven by the drive device is provided on an outer peripheral portion of the rotating decorative plate. At least one movable decoration is rotatably provided to the rotating decorative plate.

However, in the gimmick clock described in JP-A-2014-215093, since there is little room for adjusting a gear ratio between the gear and the external tooth part or the internal tooth part from a viewpoint of an arrangement space of components, a relation between a rotation period and a revolution period of the gear is limited to some extent. Therefore, novelty is less likely to occur in an operation of the decorative body. In the gimmick clock described in Japanese Patent No. 3691946, since a direction of the movable decoration is maintained by gravity, a desired operation of the movable decoration may not be achieved depending on a posture of the clock. Therefore, it is desired to develop a timepiece including a decorative body that operates more intricately and stably than a gimmick clock in the related art.

SUMMARY OF THE INVENTION

Therefore, the invention provides a timepiece including a decorative body that operates stably and intricately.

According to a first aspect of the invention, there is provided a timepiece including: a main plate provided with a tooth part extending in a circular-arc shape with a predetermined axis as a center; a rotating plate rotatable around the predetermined axis with respect to the main plate; a gear rotatably supported on the rotating plate; a transmission gear train rotatably supported on the rotating plate, meshing with the tooth part and the gear, and configured to transmit, to the gear, rotation of the main plate with respect to the rotating plate; and a decorative body non-rotatably connected to the gear and displaceable with respect to the rotating plate.

According to the invention, when the rotating plate is rotated with respect to the main plate, the gear can rotate in a rotation speed of the gear that is determined according to a speed reduction ratio in the transmission gear train and a rotation direction of the gear that is determined according to a direction of a torque transmitted to the gear by the transmission gear train. Therefore, it is possible to achieve an operation that is difficult when the decorative body is connected to a gear directly meshing with the tooth part of the main plate. Since the gear meshes with the tooth part of the main plate via the transmission gear train, it is possible to prevent a direction of the decorative body from changing depending on a posture of the timepiece. Therefore, it is possible to provide a timepiece including a decorative body that operates stably and intricately.

According to a second aspect of the invention, in the timepiece of the first aspect, the decorative body may move in parallel with respect to the main plate along with rotation of the rotating plate.

According to the invention, it is possible to provide a more interesting timepiece as compared to a timepiece in the related art.

According to a third aspect of the invention, in the timepiece of the first or second aspect, the gear may rotate with respect to the rotating plate in a direction opposite to a rotation direction of the rotating plate around the predetermined axis, and rotate at a speed reduction ratio of 1 with respect to the tooth part.

According to the invention, a rotation period of the gear with respect to the rotating plate (rotation period) can be made to coincide with a rotation period of the gear around the predetermined axis (revolution period). Since the rotation direction of the gear with respect to the rotating plate (rotation direction) is opposite to a rotation direction of the gear around the predetermined axis (revolution direction), the gear moves in parallel with respect to the main plate. Therefore, it is possible to achieve a configuration in which the decorative body moves in parallel with respect to the main plate.

According to a fourth aspect of the invention, in the timepiece of the first, second, or third aspect, the tooth part may be external teeth.

According to the invention, when the transmission gear train has a single intermediate gear meshing with the tooth part and the gear, the rotation direction of the gear with respect to the rotating plate (rotation direction) can be made opposite to the rotation direction of the gear around the predetermined axis (revolution direction). Accordingly, it is possible to achieve the configuration in which the decorative body moves in parallel with respect to the main plate using a small number of components.

According to a fifth aspect of the invention, in the timepiece of any one of the first to fourth aspect, the timepiece may further include another gear rotatably supported on the rotating plate, and the gear may be the same component as the other gear.

According to the invention, it is possible to prevent increase in a component to be newly designed in providing the timepiece achieving the operation and effect described above. Therefore, the timepiece described above can be manufactured at a low cost.

According to the invention, it is possible to provide the timepiece including the decorative body that operates stably and intricately.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of the invention will be described with reference to the drawings. In the following description, configurations having the same or similar functions are denoted by the same reference numerals. Repeated description of these configurations may be omitted.

First, a schematic configuration of a timepiece1will be described.

FIG.1is a front view of a timepiece according to an embodiment.

As shown inFIG.1, the timepiece1is a gimmick clock. The timepiece1includes a front plate2which is decorated and has an opening formed at a center thereof, a decorative plate3rotatably disposed in the opening of the front plate2, a plurality of (in this embodiment, three) front decorative bodies4which are disposed on a front side of the decorative plate3and movable, and a minute hand6and an hour hand7rotating around a central axis O (a predetermined axis) and indicating a time.FIG.1shows a state in which the decorative plate3and the front decorative bodies4are in initial positions.

The decorative plate3is formed in a disk shape centered on the central axis O. Numbers indicating the time may be clearly indicated on a front surface of the decorative plate3.

The plurality of front decorative bodies4are provided so as to be rotatable with respect to the decorative plate3. Rotation centers of the plurality of front decorative bodies4are disposed at equal angular intervals around the central axis O. Numbers indicating the time may be clearly indicated on a front surface of each of the front decorative bodies4. In this case, numbers “1” to “12” are arranged at equal angular intervals around the central axis O on the decorative plate3and the front decorative bodies4. In an initial state, the decorative plate3and the plurality of front decorative bodies4are maintained in a circular state as a whole when viewed from the front and function as a single dial.

At a predetermined time, the decorative plate3rotates around the central axis O, and the plurality of front decorative bodies4rotate while revolving around the central axis O. After a predetermined time has elapsed, the decorative plate3and the plurality of front decorative bodies4return to the initial positions. In this manner, the timepiece1executes a gimmick motion at the predetermined time. A rotation range, movement, or the like of the decorative plate3is not particularly limited, and for example, the decorative plate3may be set so as to rotate 360°. Further, the timepiece1may be configured such that music is output from a speaker while the decorative plate3is rotating.

Subsequently, a configuration of a main part of the timepiece1will be described in detail.

FIGS.2and3are plan views showing a part of the timepiece according to the embodiment.FIG.4is a cross-sectional view taken along line IV-IV inFIG.2.FIG.3shows a state in which the decorative plate3and the front decorative bodies4are removed from the part of the timepiece shown inFIG.2.

As shown inFIGS.2to4, the timepiece1includes a main plate20fixedly disposed on the front plate2(seeFIG.1), a fixed member25fixedly supported on the main plate20, a rotating plate30rotatable relative to the main plate20around the central axis O, and gears51rotatably supported on the rotating plate30and having the same number as the front decorative bodies4. In the following description, a direction along the central axis O is referred to as an axial direction, a direction orthogonal to the central axis O and radially extending from the central axis O is referred to as a radial direction, and a circumferential direction around the central axis O is simply referred to as a circumferential direction.

As shown inFIGS.3and4, the main plate20is disposed on a rear side of the decorative plate3. A movement that drives a rotary shaft8to which the minute hand6and the hour hand7are mounted, a motor that drives the rotating plate30, and the like are disposed on the rear side of the main plate20. The rotary shaft8penetrates an approximate center of the main plate20. External teeth21(tooth part) and internal teeth22are provided on a front side of the main plate20. The external teeth21extend in a circumferential shape around the central axis O. The internal teeth22extend in a circumferential shape around the central axis O (refer toFIG.3as well). The internal teeth22are provided on an outer side in the radial direction of the external teeth21. However, the external teeth21and the internal teeth22may extend less than 360° in a circular-arc shape in accordance with a moving range of the gear51to be described later. The internal teeth22may be omitted.

The fixed member25is supported on the front side of the main plate20. The fixed member25is formed in a cylindrical shape extending with the central axis O as a center and opened on both sides in the axial direction. The fixed member25surrounds the rotary shaft8. A flange portion26protruding outward in the radial direction is provided at an end portion on a front side of the fixed member25.

The rotating plate30is disposed on the front side of the main plate20and on a rear side of the flange portion26of the fixed member25. The rotating plate30is formed in a circular shape with the central axis O as a center when viewed from the front. A through-hole31into which an end portion on the rear side of the fixed member25is inserted so as to be relatively rotatable is formed at the center of the rotating plate30.

The rotating plate30includes an inner peripheral portion32extending from an inner peripheral end portion of the through-hole31to the outside in the radial direction, a stepped portion33extending from an outer peripheral end portion of the inner peripheral portion32to the rear side, and an outer peripheral portion34extending from an end portion on the rear side of the stepped portion33to the outside in the radial direction. The stepped portion33is located on the outer side in the radial direction of the external teeth21provided on the main plate20. The stepped portion33is formed with window portions35which are equal in number to the gears51and into each of which the gear51is inserted. Teeth39are formed on an outer peripheral surface of the outer peripheral portion34. The teeth39are located on an inner side in the radial direction of the internal teeth22provided on the main plate20. The teeth39mesh with a gear (not shown) and are connected to an output shaft of the motor described above.

As shown inFIG.4, the outer peripheral portion34is provided with a plurality of first shaft portions36each supporting the gear51, and a second shaft portion37supporting an intermediate gear52. The plurality of first shaft portions36are provided in the same number as the plurality of gears51. Each of the first shaft portions36and the second shaft portion37protrudes to the front side. Each of the plurality of first shaft portions36is provided at a position overlapping the window portion35formed in the stepped portion33in the circumferential direction. The first shaft portions36are provided at equal angular intervals around the central axis O. In the present embodiment, the first shaft portions36are disposed at positions corresponding to 12 o'clock, 4 o'clock, and 8 o'clock in the initial state, respectively. The second shaft portion37is close to the first shaft portion36disposed at the position corresponding to 12 o'clock among the plurality of first shaft portions36.

As shown inFIGS.3and4, the plurality of gears51are rotatably supported on the first shaft portions36, respectively. The plurality of gears51include a first gear51A disposed at the position corresponding to 12 o'clock in the initial state, and second gears51B disposed at the positions corresponding to 4 o'clock and 8 o'clock in the initial state, respectively. The first gear51A and the second gear51B are the same components. The first gear51A is separated from the external teeth21and the internal teeth22, and does not directly mesh with the external teeth21and the internal teeth22of the main plate20. Each of the second gear51B passes through the window portion35of the rotating plate30, and meshes with the external teeth21of the main plate20on the rear side of the rotating plate30. As a result, when the rotating plate30rotates with respect to the main plate20, while the second gears51B revolve around the central axis O in synchronization with the rotation of the rotating plate30, the second gears51B rotate in the same rotation direction as the revolution. The number of teeth of the second gear51B is smaller than the number of teeth of the external teeth21. Accordingly, a rotation period of the second gear51B is shorter than a revolution period of the second gear51B.

The timepiece1further includes a transmission gear train53that transmits, to the first gear51A, the rotation of the main plate20with respect to the rotating plate30. The transmission gear train53is formed of at least one gear. The transmission gear train53meshes with the external teeth21of the main plate20and the first gear51A. The transmission gear train53according to the present embodiment includes the single intermediate gear52. The intermediate gear52is rotatably supported by the second shaft portion37. The intermediate gear52is a so-called two-stage gear in which a large diameter tooth part52aand a small diameter tooth part52bare coaxially connected in the axial direction. The large diameter tooth part52ameshes with the external teeth21of the main plate20. As a result, when the rotating plate30rotates with respect to the main plate20, while the intermediate gear52revolves around the central axis O in synchronization with the rotation of the rotating plate30, the intermediate gear52rotates in the same rotation direction as the revolution. The small diameter tooth part52bis located on a front side of the large diameter tooth part52aand meshes with the first gear51A. As a result, the intermediate gear52transmits, to the first gear51A, rotation with respect to the rotating plate30(rotation).

Here, when the number of teeth of the external teeth21is X, the number of teeth of the large diameter tooth part52ais A, the number of teeth of the small diameter tooth part52bis B, and the number of teeth of the first gear51A is Y, a relation of X:A=Y:B is established. As a result, a revolution period and a rotation period of the first gear51A coincide with each other. In the present embodiment, the number of teeth of the external teeth21is 72, the number of teeth of the large diameter tooth part52ais 24, the number of teeth of the small diameter tooth part52bis 8, and the number of teeth of the first gear51A is 24. Since the transmission gear train53includes an odd number of (in the present embodiment, one) gears, the external teeth21and the first gear51A can be rotated in opposite directions with reference to the rotating plate30. As a result, a revolution direction and a rotation direction of the first gear51A are opposite to each other.

As shown inFIGS.2and4, the decorative plate3is disposed on a front side of the rotating plate30. The decorative plate3is fixedly mounted to the rotating plate30. As a result, the decorative plate3rotates around the central axis O integrally with the rotating plate30. The decorative plate3is provided with through-holes3ainto each of which a connection portion of the gear51and the front decorative body4is arranged.

The front decorative bodies4are disposed at positions corresponding to 12 o'clock, 4 o'clock, and 8 o'clock in the initial state, respectively. The front decorative bodies4include a first front decorative body4A disposed at the position corresponding to 12 o'clock in the initial state, and second front decorative bodies4B disposed at positions corresponding to 4 o'clock and 8 o'clock in the initial state, respectively. Each of the front decorative bodies4includes a plate-shaped main body portion11extending along a direction orthogonal to the axial direction. The main body portion11is provided with a claw portion11athat forms an end portion on a central axis O side in the initial state (refer toFIG.5as well). The claw portion11ais located on the rear side of the flange portion26of the fixed member25in the initial state, and overlaps the flange portion26when viewed from the axial direction. As a result, displacement of a front side of the claw portion11aof the front decorative body4is restricted, and the front decorative body4is prevented from being swayed when, for example, an impact is applied to the timepiece1. The front decorative bodies4are non-rotatably connected to the respective gears51one by one on a rear side of the main body portion11. The first front decorative body4A is fixed to the first gear51A. The second front decorative bodies4B are fixed to the respective second gears51B one by one. Since the front decorative body4is fixed to the gear51, the front decorative body4rotates integrally with the gear51with respect to the rotating plate30and the decorative plate3. Each of the front decorative bodies4is formed in a shape that does not interfere with each other and does not come into contact with the fixed member25when rotating with respect to the rotating plate30.

Next, an operation of the timepiece1will be described in detail.

As shown inFIGS.1to3, in the initial state of the timepiece1as described above, the decorative plate3and the plurality of front decorative bodies4are maintained in the circular state as a whole when viewed from the front.

FIG.5is a plan view showing a state in which the part of the timepiece shown inFIG.2is displaced.FIG.6is a plan view showing a part of the timepiece shown inFIG.5.FIG.6shows a state in which the decorative plate3and the front decorative bodies4are removed from the part of the timepiece shown inFIG.5.

Here, as shown inFIGS.5and6, when the motor is driven to rotate the rotating plate30with respect to the main plate20, the gears51and the intermediate gear52revolve. Since the second gears51B and the intermediate gear52mesh with the external teeth21of the main plate20, the second gears51B and the intermediate gear52rotate in synchronization with the revolution. Along with the rotation of the intermediate gear52, the first gear51A meshing with the intermediate gear52also rotates in synchronization with the revolution. As a result, the front decorative body4fixedly mounted to the gear51also rotates with respect to the decorative plate3. At this time, since the revolution direction and the rotation direction of the first gear51A are opposite to each other and the revolution period and the rotation period of the first gear51A coincide with each other, the first front decorative body4A moves in parallel (translates) with respect to the front plate2. Meanwhile, since a revolution direction and a rotation direction of the second gear51B coincide with each other, the second front decorative body4B rotates with respect to the front plate2.

As described above, the timepiece1according to the present embodiment includes: the first gear51A rotatably supported on the rotating plate30; the intermediate gear52rotatably supported on the rotating plate30, meshing with the external teeth21of the main plate20and the first gear51A, and transmitting, to the first gear51A, the rotation of the main plate20with respect to the rotating plate30; and the first front decorative body4A non-rotatably connected to the first gear51A and displaceable with respect to the rotating plate30. According to this configuration, when the rotating plate30is rotated with respect to the main plate20, the first gear51A can rotate in a rotation speed of the first gear51A that is determined according to a speed reduction ratio in the intermediate gear52and a rotation direction of the first gear51A that is determined according to a direction of a torque transmitted to the first gear51A by the intermediate gear52. Therefore, it is possible to achieve an operation that is difficult when the front decorative body is connected to a gear directly meshing with the external teeth21or the internal teeth22of the main plate20. Further, since the first gear51A meshes with the external teeth21of the main plate20via the transmission gear train53, it is possible to prevent a direction of the first front decorative body4A from changing depending on a posture of the timepiece1. Therefore, it is possible to provide a timepiece including the front decorative body4that operates stably and intricately.

In addition, the first front decorative body4A moves in parallel to the main plate20along with the rotation of the rotating plate30. According to this configuration, it is possible to provide a more interesting timepiece as compared to a timepiece in the related art.

The first gear51A rotates in a direction opposite to the revolution direction and rotates at a speed reduction ratio of 1 with respect to the external teeth21of the main plate20. According to this configuration, the rotation period of the first gear51A can be made to coincide with the revolution period of the first gear51A. In addition, since the rotation direction of the first gear51A is opposite to the revolution direction of the first gear51A, the first gear51A moves in parallel with respect to the main plate20. Therefore, it is possible to achieve a configuration in which the first front decorative body4A moves in parallel with respect to the main plate20.

The intermediate gear52meshes with the external teeth21of the main plate20. According to this configuration, the rotation direction of the first gear51A can be made opposite to the revolution direction of the first gear51A by the single intermediate gear52. Accordingly, it is possible to achieve a configuration in which the first front decorative body4A moves in parallel with respect to the main plate20using a small number of components.

The timepiece1further includes the second gears51B rotatably supported on the rotating plate. The first gear51A is the same component as the second gears51B. According to this configuration, it is possible to prevent increase in a component to be newly designed in providing the timepiece1achieving the operation and effect described above. Therefore, the timepiece1described above can be manufactured at a low cost.

The invention is not limited to the embodiments described with reference to the drawings, and various modifications can be considered within the technical scope of the invention.

For example, in the embodiment described above, three front decorative bodies4are provided, but the invention is not limited to this configuration. The number of the front decorative bodies can be set to any number.

In the embodiment described above, the transmission gear train53is implemented by the single intermediate gear52, but the transmission gear train may be implemented by a plurality of gears. However, when the transmission gear train meshes with the external teeth21of the main plate20in the same manner as in the embodiment described above, it is desirable that the number of the gears implementing the transmission gear train is an odd number. As a result, the external teeth21and the first gear51A can be rotated in opposite directions with reference to the rotating plate30to make the revolution direction and the rotation direction of the first gear51A opposite to each other. Therefore, as in the embodiment described above, the first front decorative body4A can move in parallel with respect to the main plate20.

In the embodiment described above, the transmission gear train53meshes with the external teeth21of the main plate20, but the invention is not limited to this configuration. That is, the transmission gear train may mesh with the first gear51A and the internal teeth22of the main plate20. In this case, it is desirable that the number of the gears implementing the transmission gear train is an even number. As a result, the internal teeth22and the first gear51A can be rotated in opposite directions with reference to the rotating plate30to make the revolution direction and the rotation direction of the first gear51A opposite to each other. Therefore, as in the embodiment described above, the first front decorative body4A can move in parallel with respect to the main plate20.

In the embodiment described above, the first front decorative body4A is formed to move in parallel, but the operation of the first front decorative body is not particularly limited. However, it is desirable that the first front decorative body performs an operation different from that of the second front decorative bodies4B.

In addition, it is possible to appropriately replace components in the embodiments described above with known components without departing from the spirit of the invention.