CLASP, STRAP OF ORNAMENT, AND TIMEPIECE

Description

RELATED APPLICATIONS

This application claims priority to Japanese Patent application No. JP2024-174880, filed on October 4, 2024, 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 clasp, a strap of ornament, and a timepiece.

2. Description of Related Art

In the related art, various configurations of a clasp have been proposed as a fastener for a strap of ornament such as a wristwatch.

For example, JP2020-199207A discloses a configuration of a clasp including a foldable belt-shaped fastener main body, a protrusion portion provided at one end of the fastener main body, and an engagement mechanism provided at the other end of the fastener main body and to be engaged with the protrusion portion. The engagement mechanism includes a box body and a pair of engagement members that is accommodated in the box body and form an engagement portion to be engaged with the protrusion portion. A portion of the engagement member that protrudes outward in a width direction of the strap from the box body is an operation portion that can be operated by a user. According to the technique disclosed in JP2020-199207A, by pushing the pair of operation portions in the width direction, the engagement between the protrusion portion and the engagement portion is released, and the clasp can be opened.

In a clasp used for a strap for ornament such as a timepiece, as a result of considering a design property, the protrusion portion and the engagement portion (the engagement member) may be formed of different metal materials. For example, the protrusion portion integrally formed with the fastener main body may be made of stainless steel, and the engagement member, which is also a design member, may be made of a noble metal such as a titanium alloy. In this case, when the protrusion portion and the engagement member are repeatedly engaged with each other, the engagement member is likely to be deformed or damaged. That is, in the related art, in particular, when the protrusion portion and the engagement portion are formed of different metal materials, the strength of the engagement member may not be sufficiently ensured.

In the technique disclosed in JP2020-199207A, the engagement mechanism is formed by disposing the engagement member in the box body whose side portions (both sides of the strap in the width direction) are opened and then attaching a lid that covers an upper portion of the box body. Here, FIG. 13 is a side view of an engagement mechanism 105A of a clasp 101A according to the related art such as JP2020-199207A. As illustrated in FIG. 13, in the related art such as JP2020-199207A, when an engagement mechanism 105A after assembly is viewed from the side (in the width direction), a boundary portion 118 with a lid body 130 is present on a side surface 120a of a box body 120, and thus the appearance quality of the side surface 120a may be deteriorated.

To solve this problem, for example, it is conceivable to form the clasp by inserting the engagement member into the side surface of the box body. FIG. 14 is a side view of an engagement mechanism 105B of a clasp 101B according to another related art. FIG. 15 is a perspective view illustrating an attachment step of the engagement mechanism 105B according to another related art illustrated in FIG. 14. As illustrated in FIG. 14, in the related art, an operation portion 171 of an engagement member 170 is inserted into a through hole 119 surrounded by the side surface 120a on four sides in the side surface 120a of the box body 120. Accordingly, the engagement mechanism 105B can be formed without forming the boundary portions 118 (see FIG. 13) on the side surface 120a of the box body 120. However, in such a configuration, an attachment task of the engagement mechanism 105B may be complicated. That is, as illustrated in FIG. 15, in the configuration in which the engagement member 170 is inserted into the through hole 119, in a step of disposing the engagement member 170 in the box body 120, a so-called oblique assembly is required in which the other engagement member 170b is provided in a state in which one engagement member 170a is lifted and inclined. Therefore, the operation portion 171 is likely to be damaged at the time of the oblique assembly, and the yield may decrease. To perform the oblique assembly, it is necessary to form an inner shape of the through hole 119 larger than the operation portion 171. Therefore, when the box body 120 is viewed from the side, a gap S (see FIG. 14) between the side surface 120a of the box body 120 and the operation portion 171 increases, and as a result, the appearance quality may decrease.

SUMMARY OF THE INVENTION

It is an aspect of the present application to provide a clasp capable of improving both appearance quality and strength as compared with those in the related art, and a strap of ornament and a timepiece including the clasp.

A clasp according to one aspect of the application is a clasp connected to a strap of ornament, the clasp including: a housing having openings at both end portions in a width direction of the strap; a pair of engagement members provided in the housing and forming an engagement portion to be engaged with one end portion of the clasp; and a pair of operation members connected to the pair of engagement members, respectively, and inserted into the openings.

According to this configuration, the engagement members forming the engagement portion to be engaged with one end portion of the clasp and the operation members inserted into the openings and to be operated by the user are formed by different components (members). Accordingly, the engagement members and the operation members can be formed of different materials. For example, the engagement members may be formed of high-strength steel such as stainless steel, and the operation members may be formed of a noble metal such as titanium. Therefore, it is possible to prevent deterioration in design property of the operation members while ensuring the strength of the engagement portion in the engagement members.

Since the engagement member and the operation member are formed of different components, that is, are formed to be separable from each other, the engagement member and the operation member can be attached to the housing without performing an oblique assembly. Therefore, as compared with the related art (for example, see FIG. 15) in which the attachment is performed by the oblique assembly, damage to the operation member and a decrease in yield can be prevented. Even in a case of a configuration in which the operation members are inserted into the openings in each of which four sides are surrounded by the side surface, since it is not necessary to obliquely assemble the operation members, it is not necessary to increase sizes of the openings more than necessary with respect to the outer shapes of the operation members. Therefore, as compared with the related art, the gap between the opening and the operation member can be reduced, and the appearance quality can be improved. Since an attachment task can be easily performed, the assembly cost can be reduced. Since the housing has openings in each of which four sides are surrounded by the side surface, it is possible to prevent the boundary portion (see FIG. 13) from being formed in the side surface of the housing as compared with that in the related art (see FIG. 13) in which the operation members are sandwiched between the housing and the lid body. Therefore, the appearance quality can be further improved.

Therefore, it is possible to provide a clasp capable of improving both the appearance quality and the strength as compared with those in the related art.

The clasp further includes: a locking protrusion provided at the one end portion of the clasp and configured to be inserted into the housing, and the engagement portion is detachably engaged with the locking protrusion.

According to this configuration, since the engagement portion is provided in the engagement members, the engagement members (that is, the engagement portion) can be formed of a high-strength material without deteriorating the design property of the operation members. Therefore, it is possible to improve the strength of the engagement portion while preventing a decrease in the design property. Since the engagement members can be formed of a high-strength material, the engagement portion can be reduced in size and thickness. Therefore, the production cost can be reduced.

In the clasp, the pair of operation members includes a first operation member that protrudes outward of the housing from a first opening that is one of the openings provided at both end portions of the housing and that is pressed to be operated, and a second operation member that protrudes outward of the housing from a second opening different from the first opening of the openings and that is pressed to be operated, and the first operation member and the second operation member are disposed close to one of side surfaces of the housing in a direction orthogonal to a protruding direction of the operation member in a plan view of the housing.

According to this configuration, since the first operation member and the second operation member are disposed close to one side surface, rattling of the first operation member and the second operation member can be prevented. Accordingly, the design property of the operation members can be improved. Since the first operation member and the second operation member can be disposed along the one side surface, the assembling workability of the first operation member and the second operation member can be improved.

In the clasp, the pair of engagement members includes a first engagement member connected to one operation member of the pair of operation members, and a second engagement member connected to the other operation member of the pair of operation members, and the clasp includes a first elastic member that biases the first engagement member in a protruding direction of the one operation member, and a second elastic member that biases the second engagement member in a protruding direction of the other operation member.

According to this configuration, the first elastic member biases the first piece including the first engagement member and the first operation member toward a side of one opening. The second elastic member biases the second piece including the second engagement member and the second operation member toward a side of the other opening. Accordingly, in a state in which no external force is applied to the first piece and the second piece, the engagement portion can maintain an engagement state with one end portion of the clasp by the elastic force. The elastic members abut against the engagement members, respectively, instead of the operation members. Accordingly, when the engagement members are formed of a high-strength material, the strength of abutting portions with the elastic members can be increased. Therefore, the operability when the user operates the operation members can be improved. Since the elastic members prevent the rattling of the first piece and the second piece, the appearance quality of the clasp can be improved.

In the clasp, the operation member is made of a titanium alloy.

According to this configuration, the design property of the operation members can be improved.

In the clasp, the engagement member is made of stainless steel.

According to this configuration, the strength of the engagement members can be increased. Since the strength of the engagement portion formed by the engagement members is increased, the engagement strength when engaging with the one end portion of the clasp can be increased, and the life of the engagement portion can be improved.

In the clasp, at least one of the operation member and the engagement member has a connection portion that connects the operation member and the engagement member to each other.

According to this configuration, the operation members and the engagement members can be firmly connected by providing the connection portions. Since the connection portions are provided on at least one of the operation members and the engagement members, the number of components can be reduced and the assembling workability can be improved as compared with a case in which the connection portions are implemented by different components.

In the clasp, the connection portion is formed to have an uneven shape, and the operation member and the engagement member connected to each other are connected by being engaged with each other in a thickness direction thereof.

According to this configuration, since the operation member and the engagement member are engaged with each other in the thickness direction, the engagement member can be disposed from above the housing, for example, after the operation member is disposed in the housing. Therefore, the assembling workability can be improved.

A strap of ornament according to one aspect of the application includes the clasp described above.

According to this configuration, it is possible to provide the strap of ornament including the clasp capable of improving both the appearance quality and the strength as compared with those in the related art.

A timepiece according to one aspect of the application includes a timepiece main body and the straps described above connected to the timepiece main body.

According to this configuration, for example, the application can be applied to the wristwatch. Therefore, it is possible to provide the timepiece provided with the strap including the clasp capable of improving both the appearance quality and the strength as compared with those in the related art.

According to the invention, a clasp capable of improving both appearance quality and strength as compared with those in the related art, and a strap of ornament and a timepiece including the clasp can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view illustrating an example of a timepiece according to a first embodiment.

FIG. 2 is a side view of a clasp according to the first embodiment.

FIG. 3 is a perspective view of an engagement mechanism according to the first embodiment as viewed from a back side.

FIG. 4 is a perspective view of the clasp according to the first embodiment as viewed from the back side.

FIG. 5 is a perspective view of a first piece.

FIG. 6 is a perspective view of a second piece.

FIG. 7 is a diagram illustrating an operation member arrangement step in an attachment step of the engagement mechanism.

FIG. 8 is a diagram illustrating the engagement member arrangement step in the attachment step of the engagement mechanism.

FIG. 9 is a diagram illustrating an elastic member arrangement step in the attachment step of the engagement mechanism.

FIG. 10 is a diagram illustrating a lid body placement step in the attachment step of the engagement mechanism.

FIG. 11 is a perspective view of an engagement mechanism according to a second embodiment.

FIG. 12 is a perspective view of the engagement mechanism according to the second embodiment with a lid body attached thereto.

FIG. 13 is a side view of an engagement mechanism of a clasp according to the related art.

FIG. 14 is a side view of an engagement mechanism of a clasp according to another related art.

FIG. 15 is a perspective view illustrating an attachment step of the engagement mechanism according to the other related art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of the invention will be described with reference to drawings. In the following description, configurations having the same or similar functions are denoted by the same reference signs. A duplicate description of these configurations may be omitted. In the following embodiments, a wristwatch 10 will be described as an example of ornament, but the "ornament" in the claims is not limited to a wristwatch. In the following description, a side facing the wrist when the wristwatch is worn on the wrist of the user may be referred to as a back side, and the opposite side may be referred to as a front side. In the following description, unless otherwise specified, a "width direction" and a "longitudinal direction" coincide with a width direction and a longitudinal direction of the ornament, that is, straps 13.

First Embodiment

FIG. 1 is a plan view illustrating an example of a timepiece 10 according to a first embodiment. The timepiece 10 illustrated in FIG. 1 is the wristwatch 10 and includes a timepiece main body 10a and the straps 13 (a strap of ornament in the claims).

The timepiece main body 10a includes, for example, a dial, hands, and a movement that controls movements of the hands in a timepiece case. For example, the timepiece case is formed of a case body that is a frame made of metal, windshield glass made of a transparent material such as glass or plastic, and a case back made of metal. A pair of straps 13 is formed in a band shape and are respectively connected to both sides of the timepiece main body 10a.

FIG. 2 is a side view of a clasp 1 according to the first embodiment.

The clasp 1 is, for example, the clasp 1 for the wristwatch 10 illustrated in FIG. 1. The clasp 1 is provided at an end portion of each of the straps 13 opposite to the timepiece main body 10a, and connects the pair of straps 13. The clasp 1 includes a rail 2 and an engagement mechanism 5.

The rail 2 includes an inner rail 3 having one end portion connected to one of the straps 13, and an outer rail 4 connected to the inner rail 3 via a hinge 12 at the other end portion of the inner rail 3. The inner rail 3 and the outer rail 4 are band-shaped members having substantially the same length. The inner rail 3 and the outer rail 4 overlap each other when the wristwatch 10 is worn, and are each curved in an arc shape when viewed from the side to fit the wrist of the user. A state in which the inner rail 3 and the outer rail 4 overlap each other is a state in which a main surface of the arc-shaped inner rail 3 that is a surface on an outer peripheral side and a back surface of the arc-shaped outer rail 4 that is a surface on an inner peripheral side overlap each other. In the present embodiment, the inner rail 3 is formed to have a width dimension larger than that of the outer rail 4 (also see FIG. 4). A recessed portion 14 is provided in a portion of the inner rail 3 overlapping the outer rail 4, and the outer rail 4 is accommodated in the recessed portion 14 when the wristwatch 10 is worn. In the example illustrated in FIG. 4, a through hole is formed as the recessed portion 14. By providing the recessed portion 14, a surface (the main surface) of the inner rail 3 and a surface of the outer rail 4 are flush with each other in the state in which the inner rail 3 and the outer rail 4 overlap each other.

As illustrated in FIG. 2, a lock pin 11 (a locking protrusion in the claims) provided to stand on the main surface of the inner rail 3 is provided on one end portion of the inner rail 3 located on a side opposite to the hinge 12. The lock pin 11 includes a cylindrical stem portion 11a and a hemispherical portion 11b provided at a tip of the stem portion 11a. The hemispherical portion 11b is formed in a hemispherical shape having a diameter larger than that of the stem portion 11a. The hemispherical portion 11b is formed such that the diameter thereof decreases toward a tip of the lock pin 11. The lock pin 11 is inserted into a box body 20 of the engagement mechanism 5, which will be described in detail later, and is detachably engaged with an engagement portion 9 of the engagement mechanism 5.

The outer rail 4 is pivotably connected to the other end portion of the inner rail 3 via the hinge 12 provided at the other end portion of the inner rail 3. Among both end portions of the outer rail 4 in the longitudinal direction, the engagement mechanism 5 is fixed to the other end portion on a side opposite to one end portion to which the inner rail 3 is connected. The engagement mechanism 5 is provided at a position corresponding to the lock pin 11 of the inner rail 3 in the state in which the inner rail 3 and the outer rail 4 overlap each other.

FIG. 3 is a perspective view of the engagement mechanism 5 according to the first embodiment as viewed from the back side. FIG. 4 is a perspective view of the clasp 1 according to the first embodiment as viewed from the back side.

As illustrated in FIGS. 3 and 4, the engagement mechanism 5 includes the box body 20 (a housing in the claims), a lid body 30, a first piece 40, a second piece 50, elastic members 61 and 62, and the engagement portion 9. In FIG. 3, the lid body 30 is indicated by a dotted line to describe the internal configuration of the box body 20.

As illustrated in FIGS. 2 and 3, the box body 20 is fixed to the other end portion of the outer rail 4. The box body 20 is formed in a box shape that opens toward the back side (the side facing the wrist when the wristwatch 10 is worn). As illustrated in FIG. 3, specifically, the box body 20 includes a bottom wall 25 located on the front side opposite to the opening, a right side wall 21, a left side wall 22, and a front side wall 24 (one of side surfaces in the claims) that stand upright from the bottom wall 25. The box body 20 is formed in a rectangular shape in a plan view in which a length dimension along the width direction of the strap 13 (a distance dimension between the right side wall 21 and the left side wall 22) is larger than a length dimension along the longitudinal direction of the strap 13 (a distance dimension from the front side wall 24 to a rear end portion 23). The outer rail 4 is connected to the rear end portion 23 of the box body 20 via a spring rod 32, which will be described in detail later.

A first opening 17 (an opening in the claims) is formed in the right side wall 21. The first opening 17 penetrates the right side wall 21 in the width direction. As illustrated in FIG. 2, the first opening 17 according to the present embodiment is formed in a trapezoidal shape in which a thickness along a front-back direction decreases from the rear end portion 23 toward the front side wall 24 as viewed from the width direction. In this way, since a shape of the first opening 17 is formed along an outer shape of the box body 20, the width dimension of the right side wall 21 located on both sides of the first opening 17 in the front-back direction is uniform as viewed from the width direction, and the design property can be improved.

Similarly, a second opening 18 (an opening in the claims) is formed in the left side wall 22. The second opening 18 penetrates the left side wall 22 in the width direction. The second opening 18 is formed in the same shape as the first opening 17.

As illustrated in FIGS. 3 and 4, the lid body 30 includes a lid main body 31, the spring rod 32, and a pair of set screws 33. The lid body 30 covers the opening of the box body 20. The lid main body 31 is formed in a plate shape. As illustrated in FIG. 3, a front end portion of the lid main body 31 is locked to the front side wall 24 of the box body 20. A rear end portion of the lid main body 31 is formed such that the spring rod 32 can be inserted therein along the width direction. When the lid main body 31 is attached to the box body 20, a protrusion at the front end portion of the lid main body 31 is first locked to a recessed portion of the box body 20 in a state in which the spring rod 32 is inserted into the lid main body 31. Next, both end portions of the spring rod 32 protruding from both sides of the rear end portion of the lid main body 31 are locked to the right side wall 21 and the left side wall 22 of the box body 20. Accordingly, the lid body 30 is fixed to the box body 20. An attachment structure of the lid body 30 is not limited to the embodiment described above.

As illustrated in FIGS. 3 and 4, a hole 35 penetrating the lid main body 31 in a thickness direction is formed in a central portion of the lid main body 31. The hole 35 allows the lock pin 11 (see FIG. 2) to pass therethrough in the state in which the inner rail 3 and the outer rail 4 overlap each other. The set screws 33 are attached to both sides of the hole 35 in the width direction. Each of the set screws 33 is fixed to the lid main body 31 and protrudes from the lid main body 31 toward an inside of the box body 20.

FIG. 5 is a perspective view of the first piece 40. The first piece 40 is formed in a plate shape to be accommodated in the box body 20. As illustrated in FIGS. 3 and 5, the first piece 40 includes a first operation member 42, a first engagement member 41, and a first connection portion 45. The first piece 40 is disposed close to a right side of the box body 20 (see FIG. 3).

Most of the first operation member 42 is accommodated in the box body 20. An outer end portion of the first operation member 42 in the width direction is inserted into the first opening 17 of the box body 20 and protrudes to the outside of the box body 20 via the first opening 17. A portion of the first operation member 42 that protrudes from the first opening 17 is an operation portion that can be pressed and operated by the user. The operation portion is formed in a trapezoidal shape similar to the first opening 17 as viewed from the width direction. The first operation member 42 is formed of, for example, a titanium alloy. A large-diameter hole 46 (see FIG. 5) penetrating in the thickness direction is formed in a portion of the first operation member 42 that is located in the box body 20. The set screw 33 of the lid body 30 is inserted into the large-diameter hole 46. An inner diameter of the large-diameter hole 46 is larger than an outer diameter of the set screw 33 provided in the lid body 30. By inserting the set screw 33 into the large-diameter hole 46, the first operation member 42 is prevented from falling off from the first opening 17, and the first operation member 42 can be moved in the width direction when the operation portion is operated.

The first engagement member 41 is provided on an inner side relative to the first operation member 42 in the width direction. The first engagement member 41 is connected to an end portion of the first operation member 42 on a side opposite to the portion protruding to the outside of the box body 20, that is, an inner end portion in the width direction by the first connection portion 45. A detailed configuration of the first connection portion 45 will be described later. The first engagement member 41 is formed in a U shape that opens rearward in a front view as viewed in the front-back direction. The first engagement member 41 is formed of a component different from the first operation member 42. In the present embodiment, the first engagement member 41 is formed of stainless steel.

As illustrated in FIG. 5, the first connection portion 45 connects the first operation member 42 and the first engagement member 41. The first connection portion 45 is provided on at least one of the first operation member 42 and the first engagement member 41. In the present embodiment, the first connection portion 45 is provided on both the first operation member 42 and the first engagement member 41. Specifically, a projection portion 45a protruding toward a side of the lid body 30 is formed at an inner end portion of the first operation member 42 in the width direction. Meanwhile, a recessed portion 45b with which the projection portion 45a can be engaged is formed at an outer end portion of the first engagement member 41 in the width direction. Therefore, the first connection portion 45 is formed to have an uneven shape. The first operation member 42 and the first engagement member 41 are connected to each other by engaging with each other in the thickness direction (the front-back direction).

FIG. 6 is a perspective view of the second piece 50. The second piece 50 is formed in a plate shape to be accommodated in the box body 20. As illustrated in FIGS. 3 and 6, the second piece 50 includes a second operation member 52, a second engagement member 51, and a second connection portion 55. The second piece 50 is disposed close to a left side of the box body 20 (see FIG. 3).

Most of the second operation member 52 is accommodated in the box body 20. An outer end portion of the second operation member 52 in the width direction is inserted into the second opening 18 of the box body 20 and protrudes to the outside of the box body 20 via the second opening 18. A portion of the second operation member 52 that protrudes from the second opening 18 is an operation portion that can be pressed and operated by the user. The operation portion is formed in a trapezoidal shape similar to the second opening 18 as viewed from the width direction. The second operation member 52 is formed of, for example, a titanium alloy. A large-diameter hole 56 (see FIG. 6) penetrating in the thickness direction is formed in a portion of the second operation member 52 that is located in the box body 20. The set screw 33 of the lid body 30 is inserted into the large-diameter hole 56. An inner diameter of the large-diameter hole 56 is larger than an outer diameter of the set screw 33 provided in the lid body 30. By inserting the set screw 33 into the large-diameter hole 56, the second operation member 52 is prevented from falling off from the second opening 18, and the second operation member 52 can be moved in the width direction when the operation portion is operated.

The second engagement member 51 is provided on an inner side relative to the second operation member 52 in the width direction. The second engagement member 51 is connected to an end portion of the second operation member 52 on a side opposite to the portion protruding to the outside of the box body 20, that is, an inner end portion in the width direction by the second connection portion 55. The second connection portion 55 includes a projection portion 55a formed on the second operation member 52 and a recessed portion 55b formed on the second engagement member 51 and engageable with the projection portion 55a. Since the configuration of the second connection portion 55 is the same as the configuration of the first connection portion 45 described above, a detailed description thereof will be omitted. The second engagement member 51 is formed of a component different from the second operation member 52. In the present embodiment, the second engagement member 51 is formed of stainless steel. The second engagement member 51 is formed in a U shape that opens forward in a front view as viewed in the front-back direction. Therefore, as illustrated in FIG. 3, the first engagement member 41 and the second engagement member 51 are disposed such that openings thereof face each other. A part of the inner end portion of the second engagement member 51 in the width direction enters the U-shaped opening of the first engagement member 41. Similarly, a part of the inner end portion of the first engagement member 41 in the width direction enters the U-shaped opening of the second engagement member 51. The second engagement member 51 may be a common component with the first engagement member 41.

The first piece 40 and the second piece 50 are disposed closer to one of directions orthogonal to a protruding direction of the operation members 42 and 52 in a plan view as viewed in the front-back direction. In the present embodiment, the first piece 40 and the second piece 50 are disposed close to the front side wall 24 (one of side surfaces in the claims) of the box body 20.

The pair of elastic members 61 and 62 is provided in the box body 20. The elastic members include a first elastic member 61 and a second elastic member 62. The first elastic member 61 is provided between the first engagement member 41 and the left side wall 22. The first elastic member 61 biases the first piece 40 (the first engagement member 41) in the protruding direction of the first operation member 42 (for example, rightward in the width direction). The left side wall 22 and the first engagement member 41 may be provided with a recess or the like for holding or positioning an end portion of the first elastic member 61. The second elastic member 62 is provided between the second engagement member 51 and the right side wall 21. The second elastic member 62 biases the second piece 50 (the second engagement member 51) in the protruding direction of the second operation member 52 (for example, leftward in the width direction). The right side wall 21 and the second engagement member 51 may be provided with a recess or the like for holding or positioning an end portion of the second elastic member 62.

By forming the first piece 40 and the second piece 50 as described above, a pair of operation members (the first operation member 42 and the second operation member 52) and a pair of engagement members (the first engagement member 41 and the second engagement member 51) are provided in the box body 20. One of the pair of engagement members (for example, the first engagement member 41) is attached such that the inner end portion in the width direction is inserted into the opening of the other engagement member (for example, the second engagement member 51). Accordingly, the pair of engagement members 41 and 51 forms the engagement portion 9 in which the inner end portions in the width direction face each other in the width direction. The engagement portion 9 is provided at a central portion of the box body 20. The engagement portion 9 is detachably engaged with the lock pin 11 of the inner rail 3. The engagement portion 9 is opened and closed to approach or separate from each other in the width direction. For example, when the user presses the operation portions of the operation members 42 and 52 inward with fingers, the pair of engagement members 41 and 51 moves in directions away from each other in the engagement portion 9. In contrast, when the user takes hands off from the operation portions, the pair of engagement members 41 and 51 moves toward each other by a spring force. Therefore, by operating the operation members 42 and 52, a gap between the pair of engagement members 41 and 51 (an inner diameter of the engagement portion 9) can be changed. As a result, when the user overlaps the inner rail 3 and the outer rail 4, the hemispherical portion 11b of the lock pin 11 is locked to the engagement portion 9, and the clasp 1 is closed. In contrast, in a state in which the lock pin 11 is locked, the user presses the operation portions to disengage the lock pin 11 from the engagement portion 9, and the clasp 1 is opened.

Next, an attachment step (a method) of the engagement mechanism 5 described above will be described.

FIG. 7 is a diagram illustrating an operation member arrangement step in the attachment step of the engagement mechanism 5. FIG. 8 is a diagram illustrating an engagement member arrangement step in the attachment step of the engagement mechanism 5. FIG. 9 is a diagram illustrating an elastic member arrangement step in the attachment step of the engagement mechanism 5. FIG. 10 is a diagram illustrating a lid body placement step in the attachment step of the engagement mechanism 5.

As illustrated in FIG. 7, in the attachment step of the engagement mechanism 5, first, the first operation member 42 and the second operation member 52 are disposed in the box body 20. The first operation member 42 is inserted into the box body 20 from the outside of the first opening 17 via the first opening 17. Similarly, the second operation member 52 is inserted into the box body 20 from the outside of the second opening 18 via the second opening 18.

Next, as illustrated in FIG. 8, the first engagement member 41 and the second engagement member 51 are disposed in the box body 20. The engagement members 41 and 51 are attached to the operation members 42 and 52, respectively, in the thickness direction (the front-back direction). At this time, the first engagement member 41 is disposed such that the recessed portion 45b of the first engagement member 41 and the projection portion 45a of the first operation member 42 are engaged with each other. Similarly, the second engagement member 51 is disposed such that the recessed portion 55b of the second engagement member 51 and the projection portion 55a of the second operation member 52 are engaged with each other. By disposing the first engagement member 41 and the second engagement member 51, the first piece 40 and the second piece 50 are formed, and the engagement portion 9 is formed.

Next, as illustrated in FIG. 9, the first elastic member 61 and the second elastic member 62 are disposed in the box body 20. Specifically, the first elastic member 61 is disposed between the left side wall 22 and the first engagement member 41. The second elastic member 62 is disposed between the right side wall 21 and the second engagement member 51. At this time, the spring forces of the elastic members 61 and 62 act on the engagement members 41 and 51, respectively, and a rotation moment with a direction along the front-back direction as a rotation axis acts, but the engagement members 41 and 51 are prevented from rotating because they are connected to the operation members 42 and 52 by the connection portions 45 and 55. In other words, the connection portions 45 and 55 prevent the engagement members 41 and 51 from rotating when attaching the elastic members 61 and 62. Accordingly, the elastic members 61 and 62 can be easily attached.

Finally, as illustrated in FIG. 10, the lid body 30 to which the spring rod 32 and the set screws 33 are attached is fixed to the box body 20. The lid body 30 is attached to cover the opening of the box body 20. At this time, the pair of set screws 33 provided in the lid body 30 is inserted into the large-diameter holes 46 and 56 (see FIG. 9) of the operation members 42 and 52, respectively. The lid body 30 is disposed such that the hole 35 in the central portion of the lid body 30 and the engagement portion 9 formed by the pair of engagement members 41 and 51 overlap each other in the plan view.

By the above steps, the attachment of the engagement mechanism 5 is completed.

Operation and Effect

Next, an operation and effect of the clasp 1, the strap 13 of ornament, and the timepiece 10 described above will be described.

According to the clasp 1 of the present embodiment, the clasp 1 is the clasp 1 connected to the strap 13 of ornament, and includes the box body 20, the pair of engagement members 41 and 51, and the pair of operation members 42 and 52. The box body 20 has openings (the first opening 17 and the second opening 18) at both end portions in the width direction of the strap 13. The pair of engagement members 41 and 51 is provided in the box body 20, and form the engagement portion 9 to be engaged with one end portion (the lock pin 11 in the present embodiment) of the clasp 1. The operation members 42 and 52 are connected to the pair of engagement members 41 and 51, respectively, and are inserted into the first opening 17 and the second opening 18, respectively.

According to this configuration, the engagement members 41 and 51 forming the engagement portion 9 to be engaged with the lock pin 11 of the clasp 1 and the operation members 42 and 52 inserted into the openings 17 and 18 and to be operated by the user are formed by different components (members). Accordingly, the engagement members 41 and 51 and the operation members 42 and 52 can be formed of different materials. For example, the engagement members 41 and 51 may be formed of high-strength steel such as stainless steel, and the operation members 42 and 52 may be formed of a noble metal such as titanium. Therefore, it is possible to prevent deterioration in design property of the operation members 42 and 52 while ensuring the strength of the engagement portion 9 formed by the engagement members 41 and 51.

Since the engagement members 41 and 51 and the operation members 42 and 52 are formed by different components, that is, formed to be separable from each other, when the engagement members 41 and 51 and the operation members 42 and 52 are attached to the box body 20, they can be attached without performing an oblique assembly. Therefore, as compared with the related art (for example, see FIG. 15) in which the attachment is performed by the oblique assembly, damage to the operation members 42 and 52 and a decrease in yield can be prevented. Even in a case of a configuration in which the operation members 42 and 52 are inserted into the openings 17 and 18 in each of which four sides are surrounded by the side surface, since it is not necessary to obliquely assemble the operation members 42 and 52, it is not necessary to increase sizes of the openings 17 and 18 more than necessary with respect to the outer shapes of the operation members 42 and 52. Therefore, as compared with the related art, the gaps S (see FIG. 14) between the opening 17 and the operation member 42 and between the opening 18 and the operation member 52 can be reduced, and the appearance quality can be improved. Since an attachment task can be easily performed, the assembly cost can be reduced. Since the box body 20 has the openings 17 and 18 in each of which four sides are surrounded by the side surface, it is possible to prevent the boundary portion 118 (see FIG. 13) from being formed in the side surface of the box body 20 as compared with that in the related art (see FIG. 13) in which the operation members 42 and 52 are sandwiched between the box body 120 and the lid body 130. Therefore, the appearance quality can be further improved.

Therefore, it is possible to provide the clasp 1 capable of improving both the appearance quality and the strength as compared with those in the related art.

The clasp 1 includes the locking protrusion (the lock pin 11) provided at one end portion of the clasp 1 and to be inserted into the box body 20, and the engagement portion 9 is detachably engaged with the lock pin 11. According to this configuration, since the engagement portion 9 is provided in the engagement members 41 and 51, the engagement members 41 and 51 (that is, the engagement portion 9) can be formed of a high-strength material without deteriorating the design property of the operation members 42 and 52. Therefore, it is possible to improve the strength of the engagement portion 9 while preventing a decrease in the design property. Since the engagement members 41 and 51 can be formed of a high-strength material, the engagement portion 9 can be reduced in size and thickness. Therefore, the production cost can be reduced.

The operation member includes the first operation member 42 and the second operation member 52, and the first operation member 42 and the second operation member 52 are disposed close to one side (the front side wall 24) of the side surfaces of the box body 20 in the direction orthogonal to the protruding direction of the operation members 42 and 52 in the plan view of the box body 20. According to this configuration, since the first operation member 42 and the second operation member 52 are disposed close to the front side wall 24, rattling of the first operation member 42 and the second operation member 52 can be prevented. Accordingly, the design property of the operation members 42 and 52 can be improved. Since the first operation member 42 and the second operation member 52 can be disposed along the front side wall 24, the assembling workability of the first operation member 42 and the second operation member 52 can be improved.

The engagement member includes the first engagement member 41 and the second engagement member 51, and the clasp 1 includes the first elastic member 61 that biases the first engagement member 41 in the protruding direction of the first operation member 42 and the second elastic member 62 that biases the second engagement member 51 in the protruding direction of the second operation member 52. According to this configuration, the first elastic member 61 biases the first piece 40 including the first engagement member 41 and the first operation member 42 toward a side of the first opening 17. The second elastic member 62 biases the second piece 50 including the second engagement member 51 and the second operation member 52 toward a side of the second opening 18. Accordingly, in a state in which no external force is applied to the first piece 40 and the second piece 50, the engagement portion 9 can maintain an engagement state in which the lock pin 11 is engaged by the elastic force. The elastic members 61 and 62 abut against the engagement members 41 and 51, respectively, instead of the operation members 42 and 52. Accordingly, when the engagement members 41 and 51 are formed of a high-strength material, the strength of abutting portions with the elastic members 61 and 62 can be increased. Therefore, the operability when the user operates the operation members 42 and 52 can be improved. Since the elastic members 61 and 62 prevent the rattling of the first piece 40 and the second piece 50, the appearance quality of the clasp 1 can be improved.

The operation members 42 and 52 are formed of a titanium alloy. According to this configuration, the design property of the operation members 42 and 52 can be improved.

The engagement members 41 and 51 are formed of stainless steel. According to this configuration, the strength of the engagement members 41 and 51 can be increased. Since the strength of the engagement portion 9 formed by the engagement members 41 and 51 is increased, the engagement strength when engaging with the lock pin 11 of the clasp 1 can be increased, and the life of the engagement portion 9 can be improved.

At least one of the operation members 42 and 52 and the engagement members 41 and 51 includes the connection portions 45 and 55 that connect the operation members 42 and 52 and the engagement members 41 and 51. According to this configuration, the operation members 42 and 52 and the engagement members 41 and 51 can be firmly connected by providing the connection portions 45 and 55. Since the connection portions 45 and 55 are provided on at least one of the operation members 42 and 52 and the engagement members 41 and 51, the number of components can be reduced and the assembling workability can be improved as compared with a case in which the connection portions 45 and 55 are implemented by different components.

The connection portions 45 and 55 are formed to have an uneven shape, and the operation members 42 and 52 and the engagement members 41 and 51 connected to each other are connected by being engaged with each other in the thickness direction. According to this configuration, since the operation members 42 and 52 and the engagement members 41 and 51 are engaged with each other in the thickness direction, for example, after the operation members 42 and 52 are disposed in the box body 20, the engagement members 41 and 51 can be disposed from above the box body 20. Therefore, the assembling workability can be improved.

The strap 13 of ornament according to the present embodiment includes the clasp 1 described above. According to this configuration, it is possible to provide the strap 13 of ornament including the clasp 1 capable of improving both the appearance quality and the strength as compared with those in the related art.

The timepiece 10 according to the present embodiment includes the timepiece main body 10a and the straps 13 described above connected to the timepiece main body 10a. According to this configuration, for example, the invention can be applied to the wristwatch 10. Therefore, it is possible to provide the timepiece 10 provided with the strap 13 including the clasp 1 capable of improving both the appearance quality and the strength as compared with those in the related art.

Second Embodiment

Next, a second embodiment according to the invention will be described. In the following description, the same configurations as those of the first embodiment described above are denoted by the same reference numerals, and the description thereof will be appropriately omitted. Special configurations are not limited to these embodiments and can be appropriately changed without departing from the gist of the invention. FIG. 11 is a perspective view of an engagement mechanism 205 according to the second embodiment. FIG. 12 is a perspective view of the engagement mechanism 205 according to the second embodiment with a lid body 230 attached thereto. The second embodiment is different from the first embodiment described above in that a first opening 217 and a second opening 218 are formed in a notch shape instead of a through hole.

As illustrated in FIGS. 11 and 12, a box body 220 according to the second embodiment includes a bottom wall 225, a right side wall 221, a left side wall 222, and a front side wall 224. The first opening 217 is formed in the right side wall 221. The first opening 217 is formed in a notch shape recessed from an upper end portion (an end portion on the back side) of the right side wall 221 toward a side of the bottom wall 225. The first opening 217 is formed in a rectangular shape with an open upper end portion as viewed in the width direction. The second opening 218 is formed in the left side wall 222. Similarly to the first opening 217, the second opening 218 is formed in a notch shape recessed from an upper end portion (an end portion on the back side) of the left side wall 222 toward the side of the bottom wall 225.

The first piece 40 formed by the first engagement member 41 and the first operation member 42 is accommodated in the box body 220. The second piece 50 formed by the second engagement member 51 and the second operation member 52 is accommodated in the box body 220. Since the configurations of the first piece 40 and the second piece 50 are the same as the configurations of the first piece 40 and the second piece 50 according to the first embodiment described above, the description thereof will be omitted here.

The lid body 230 according to the second embodiment further includes a pair of extension portions 236 in addition to the configuration of the lid body 30 according to the first embodiment described above. The pair of extension portions 236 is connected to a lid main body 231 and extend from the lid main body 231 toward both sides in the width direction. The pair of extension portions 236 is provided at positions corresponding to the upper end portions of the first opening 217 and the second opening 218, respectively. The pair of extension portions 236 covers the upper end portions of the first opening 217 and the second opening 218, respectively.

According to the clasp 1 of the second embodiment, the same operation and effect as that of the first embodiment described above can be obtained. That is, since the engagement members 41 and 51 and the operation members 42 and 52 are formed of different components, for example, the engagement members 41 and 51 can be formed of high-strength steel such as stainless steel, and the operation members 42 and 52 can be formed of a noble metal such as titanium. Therefore, it is possible to prevent deterioration in design property of the operation members 42 and 52 while ensuring the strength of the engagement portion 9 formed by the engagement members 41 and 51.

Therefore, it is possible to provide the clasp 1 capable of improving both the appearance quality and the strength as compared with those in the related art.

The technical scope of the invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention.

For example, in the embodiments described above, the first connection portion 45 and the second connection portion 55 are formed in an uneven shape by the recessed portions 45a and 55a formed in the operation members 42 and 52 and the projection portions 45b and 55b formed in the engagement members 41 and 51, but the invention is not limited thereto. Projection portions may be formed in the engagement members 41 and 51, and recessed portions may be formed in the operation members 42 and 52. The first connection portion 45 and the second connection portion 55 may be formed without having an uneven shape. Specifically, for example, the operation members 42 and 52 and the engagement members 41 and 51 may be connected by adhesion.

In the embodiments described above, a configuration using coil springs as an example of the elastic members 61 and 62 has been described, but the invention is not limited thereto. It is sufficient that the elastic members 61 and 62 can bias the engagement members 41 and 51 in the protruding direction of the operation members 42 and 52, and for example, a spring in a form other than a coil spring may be used.

The material of the operation members 42 and 52 is not limited to a titanium alloy. The material of the engagement members 41 and 51 is not limited to stainless steel.

The ornament is not limited to the wristwatch 10. The configuration of the present embodiment may be applied to the strap 13 of ornament other than the wristwatch 10 and the clasp 1 provided in the strap 13.

Components in the embodiments described above can be appropriately replaced with well-known components without departing from the gist of the invention, and the embodiments described above may be appropriately combined.