HK40023310A - Fastener for ornament - Google Patents

Description

Fastener for ornament

[ technical field ]

The present invention relates to a fastening device for ornaments, which is used for separating and connecting one end and the other end of a linear member to an ornament such as a necklace or a bracelet.

[ background art ]

Conventionally, a necklace, a bracelet or the like is worn on a body by hanging a string-like member such as a chain member or a string member on a neck, an arm or the like. Fasteners having a pair of fastening members capable of being separated from and connected to each other are attached to one end portion and the other end portion of a linear member in a garnish, and the garnish can be detached by separating/connecting the pair of fastening members to each other.

As a form of a fastener used for such a garnish, for example, a snap (guide き) type, a male type, or a screw type is generally known. Among them, the snap-type fastener is most used in ornaments.

The snap-type fastener is generally formed by combining a snap member attached to one end of a linear member and a fastening ring member or a perforated sheet member attached to the other end of the linear member. In this case, the snap member has a ring portion having a part cut out and an arc-shaped movable member slidable in the ring portion, and the movable member is formed so as to be biased by a spring in a direction of closing a gap having the cut out ring portion. Such a snap-type fastener is disclosed in, for example, japanese patent application laid-open No. 2008-36244 (patent document 1).

The male type fastener is formed by combining a male member attached to one end of a linear member and a female member attached to the other end of the linear member, and the male member is locked to the female member by rotating a part of the male member in a state where the male member is inserted into the female member or by an urging force of a spring member.

Such a plug-in type fastener is disclosed in, for example, japanese patent laid-open No. 10-137016 (patent document 2), japanese patent laid-open No. 2012-19946 (patent document 3), and the like. In addition, the screw type fastener is formed by combining a male screw member and a female screw member, and the male screw member and the female screw member can be connected by screwing the male screw member into the female screw member.

As another type of fastener, there is also a fastener 60 of a medium fold type as shown in fig. 5. The middle-folding fastener 60 includes a first member 61 attached to one end of a linear member 65 and a second member 62 attached to the other end of the linear member 65, and the first member 61 is provided with a ring-shaped first connecting portion 61 a.

The second member 62 has: a base portion 62a for fixing the other end portion of the linear member 65, a sheet-like lower plate portion 62b extending linearly from the base portion 62a, a pair of left and right support portions 62c erected on the distal end portion of the lower plate portion 62b, and an opening/closing portion 62d rotatably supported by the support portions 62 c. A rotation shaft 62e rotatably supported by the support portion 62c is provided at a proximal end portion of the opening/closing portion 62d, and a bent portion 62f bent inward is provided at a distal end portion of the opening/closing portion 62 d. The bent portion 62f of the opening/closing portion 62d is formed so as to press against the outer peripheral surface of the base portion 62a while being slightly deformed when a part of the opening/closing portion 62d is brought into contact with the base portion 62a, thereby maintaining the contact state.

In this middle-folding type fastener 60, when the first member 61 and the second member 62 are coupled and separated from each other, the opening/closing portion 62d of the second member 62 is rotated to hold the second member 62 in an open state, and then the first coupling portion 61a of the first member 61 is moved so that the opening/closing portion 62d of the second member 62 passes through the opening portion 61b formed in the first coupling portion 61a, and is held in the vicinity of the support portion 62c of the second member 62. Then, the opening/closing portion 62d of the second member 62 is rotated so as to approach the lower plate portion 62b and brought into contact with the base portion 62 a. Thereby, the first member 61 and the second member 62 are coupled and maintained.

[ Prior art documents ]

Patent document

Patent document 1: japanese laid-open patent publication No. 2008-36244

Patent document 2: japanese laid-open patent publication No. 10-137016

Patent document 3: japanese patent laid-open publication No. 2012-19946

[ summary of the invention ]

Problems to be solved by the invention

For example, in the case of a snap-type fastener, since a snap-type operation (i.e., an operation of moving and holding a small movable member against an urging force) must be performed with one hand when wearing or removing a garnish, there is a problem that the operation is difficult and complicated in many cases, and thus the operability of the fastener is poor. In particular, when the snap fastener is used for a bracelet or the like, since a series of connecting and separating operations are often performed with only one hand, the operation of the fastener becomes more difficult and inconveniences the user. Further, for example, when the linear member of the garnish has design properties, the continuous design properties of the linear member may be interrupted when the snap member or the retainer ring member of the fastener is used, and as a result, the aesthetic appearance of the garnish may be impaired.

In addition, in the snap-type fastener, an outer surface side (front surface side) exposed to the outside and an inner surface side (back surface side) facing the skin of the human body cannot be distinguished. Therefore, for example, in a garnish such as a tennis bracelet, when the fastener is attached, the garnish may be turned upside down and worn in a state in which the front and back surfaces of the garnish are different (for example, in the opposite direction), and the user may not be aware of the upside-down state of the garnish and may be worn on the body.

When a plug-type fastener or a screw-type fastener is used for a bracelet or the like to perform a coupling operation, since it is necessary to perform an operation of inserting a male member while pressing a female member and locking it, or an operation of screwing a male screw member into a female screw member while pressing a female screw member, with one hand, there is a problem that the operation of the fastener is difficult, as in the case of a snap-type fastener. Further, in the case of using these fasteners, there are cases where the male member is locked, the male screw member is insufficiently screwed, and the fastener is deformed or damaged with the lapse of time during use, and as a result, the fastener may be easily and easily detached when wearing the garnish.

In the case of the middle-folding type fastener 60 shown in fig. 5, when the first member 61 and the second member 62 are coupled, the first coupling portion 61a of the first member 61 must be moved to the vicinity of the support portion 62c by the entire length of the long opening/closing portion 62d in which the distal end portion is bent and the protruding piece portion protrudes. Therefore, there is a disadvantage that the first connecting portion 61a is easily hooked to the long opening/closing portion 62 d. In general, the size of the annular first connecting portion 61a of the first member 61 is often increased so that the first member 61 is not easily hooked on the opening/closing portion 62d of the second member 62. As a result, it is difficult to reduce the size of the fastener 60 (particularly, the first member 61), and the appearance of the garnish may be impaired by the presence of the fastener 60.

In addition, in the coupled state of the fastener 60, since the bent portion 62f of the opening/closing portion 62d is pressed against the outer surface of the base portion 62a to maintain the closed state of the second member 62, there is a disadvantage that the opening/closing portion 62d is easily separated from the base portion 62a and easily opened when receiving an external force. Further, the base 62a and the opening/closing portion 62d are easily worn or deformed by repeating the opening/closing operation of the opening/closing portion 62d, and the pressing force of the opening/closing portion 62d may be weakened. Further, when the opening/closing portion 62d is easily separated from the base portion 62a and opened, the first member 61 and the second member 62 are pulled in a direction of being separated from each other by the weight of the linear member 65, and therefore, there is a problem that the opening/closing portion 62d is opened to approximately 180 °, and as a result, the first member 61 is easily separated from the second member 62.

The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a fastening device for a garnish, which can stably maintain a connected state while easily and smoothly performing a connecting operation and a separating operation, and which is less likely to cause the garnish to be turned upside down when the garnish is worn on a body.

Means for solving the problems

In order to achieve the above object, the present invention provides a fastening device for jewelry, comprising a first fastening member disposed at one end of a linear member of the jewelry, and a second fastening member disposed at the other end of the linear member and capable of being coupled to and decoupled from the first fastening member, wherein the first fastening member comprises: a first connecting portion connected to the one end portion of the linear member; a first coupling portion that is formed integrally with the first coupling portion and is coupled to the second fastening member, the first coupling portion being provided with an insertion hole portion through which a part of the second fastening member is inserted, the second fastening member including: a second connecting portion connected to the other end of the linear member; a second body portion continuously formed integrally from the second connection portion; a second coupling part extending from the second body part in a direction away from the second coupling part and having a hook-like shape coupled to the first coupling part; an insertion/extraction opening portion that communicates with the space portion inside the second coupling portion and through which a part of the first coupling portion can pass; an opening/closing portion including a substantially L-shaped or substantially arc-shaped abutting portion rotatably supported by the second body portion so as to be capable of opening and closing the insertion/extraction opening portion, and abutting against an outer peripheral surface of the second coupling portion; and a locking portion that locks the opening/closing portion when the opening/closing portion abuts against the second coupling portion to maintain the abutting state.

In the fastening device for jewelry according to the present invention, it is preferable that the locking portion has a locking recess provided in a recessed manner in an outer peripheral surface portion of the second coupling portion and a locked projection provided in the abutting portion and inserted into the locking recess.

Further, it is preferable that the second coupling portion and the opening/closing portion are inserted into the insertion hole portion of the first fastening member when the opening/closing portion is in contact with the second coupling portion.

In the fastening device for jewelry according to the present invention, it is preferable that the second fastening member has a protruding piece portion protruding outward from an outer peripheral surface of the abutting portion, and the protruding piece portion approaches the first fastening member when the abutting portion abuts against the second coupling portion.

In the present invention, it is preferable that the opening/closing unit includes: a base end portion rotatably supported by the second coupling portion; a closing portion disposed between the base end portion and the abutting portion and closing the insertion/extraction opening portion; and a side covering portion formed integrally with the base end portion and the closing portion, the side covering portion having a restricting end edge portion that extends so as to protrude inward from at least a part of the base end portion and the closing portion in a side view of the second fastening member, and the restricting end edge portion being formed obliquely or curvedly so that a space portion formed between the restricting end edge portion and a connecting portion of the closing portion and the abutting portion assumes an angle of less than 90 °.

Effects of the invention

The fastening member for jewelry according to the present invention includes a first fastening member and a second fastening member which are engaged with each other to be connectable and separable from each other, and the first fastening member includes a first connecting portion connected to one end portion of a linear member and a first connecting portion formed integrally with the first connecting portion and provided with an insertion hole portion. The second fastening member has: a second connecting portion connected to the other end of the linear member; a second body portion continuously formed integrally from the second connection portion; a second coupling part extending from the second body part in a direction away from the second coupling part and having a hook-like shape coupled to the first coupling part; an insertion/extraction opening portion that communicates with the space portion inside the second coupling portion and through which a part of the first coupling portion can pass; and an opening/closing portion including a substantially L-shaped or substantially arc-shaped abutting portion rotatably supported by the second body portion so as to be capable of opening and closing the insertion/extraction opening portion and abutting against an outer peripheral surface of the second coupling portion, and a locking portion that locks the opening/closing portion when the opening/closing portion abuts against the second coupling portion to maintain the abutting state.

When the one end portion and the other end portion of the linear member are coupled using the fastener of the present invention configured as described above, first, the first coupling portion of the first fastening member is hooked and temporarily held to the second coupling portion of the second fastening member by performing the operation of the fastener by inserting the second coupling portion of the second fastening member into the insertion hole portion provided in the first coupling portion of the first fastening member. The operation of temporarily holding such a first fastening member can be smoothly performed with only one hand. In particular, in this case, in the present invention, the first coupling portion of the first fastening member can be temporarily held by the second fastening member by passing the first coupling portion through the short tip portion (tip post portion) of the second coupling portion formed in the hook shape, and therefore, compared with, for example, the conventional fastener 60 shown in fig. 5, the first coupling portion of the first fastening member is less likely to be hooked by the second fastening member, and thus, the operation can be performed smoothly.

Then, the opening/closing portion of the second fastening member is pressed and rotated toward the second coupling portion that temporarily holds the first fastening member, and the substantially L-shaped or substantially arc-shaped contact portion of the opening/closing portion is brought into contact with the second coupling portion. Further, the opening/closing section is locked to the second connecting section or the second body section by the locking section. Thereby, the first fastening member and the second fastening member can be coupled. The operation of rotating the opening/closing portion of the second fastening member to lock the second coupling portion can be smoothly performed by only one hand.

On the other hand, when the fastener of the present invention is used to separate the one end portion and the other end portion of the linear member, the operation of detaching the first coupling portion of the first fastening member from the second coupling portion of the second fastening member may be performed after the open-close portion of the second fastening member is rotated so as to be separated from the second coupling portion by releasing the locked state. Such a fastener detaching operation can be smoothly performed with only one hand.

Therefore, in the present invention, the fastening operation and the separation operation of the fastener can be easily and smoothly performed only by one hand. Further, when the first fastening member and the second fastening member of the fastening tool are coupled to each other, the opening/closing portion of the second fastening member is locked to the second coupling portion by the locking portion, and therefore, the state in which the opening/closing portion and the second coupling portion are in contact with each other can be maintained. This can stably maintain the coupled state of the first fastening member and the second fastening member.

In the fastener of the present invention, as described above, the operation of coupling the first fastening member and the second fastening member is performed by rotating the opening/closing portion of the second fastening member, and therefore, the orientation of the outer surface side (front surface side) and the orientation of the inner surface side (back surface side) of the fastener can be easily confirmed or held unconsciously at the time of the coupling operation. As a result, for example, when a conventional snap-type fastener is used, the tennis bracelet or other accessory is not easily put on the body in an upside-down state, and the accessory can be urged to be worn in a correct orientation.

In addition, in the fastener of the present invention, the first fastening member and the second fastening member can be easily made smaller in size as a whole without reducing the operability of the fastener. In particular, in the present invention, as described above, when temporarily holding the first coupling portion of the first fastening member to the second fastening member, the short distal end portion of the second coupling portion is inserted, and therefore, the first coupling portion is less likely to be hooked on the second fastening member. As a result, the first connecting portion of the first fastening member can be formed smaller (or thinner) than the first connecting portion 61a of the conventional fastener 60 shown in fig. 5. Moreover, the fastener of the present invention can be easily set longer or shorter along the length of the linear member. Therefore, for example, when the linear member of the garnish has design properties, the fastener of the present invention can easily adjust the size of the fastener itself in accordance with the design thereof, and therefore, the continuous design properties of the linear member can be easily maintained, and the beauty of the garnish is not easily impaired.

In the fastening device for jewelry of the present invention, the engaging portion includes an engaging recess recessed in an outer peripheral surface of the second coupling portion and an engaged projection provided in the abutting portion and inserted into the engaging recess. Thus, the engaging portion can be easily provided to the second fastening member with a simple configuration. Further, the opening/closing portion can be smoothly locked to the second coupling portion by the locking portion, and the locked state can be stably maintained, so that the fastener can be made less likely to be easily detached. In this case, for example, the function of maintaining the contact state of the opening/closing portion can be maintained for a longer period of time than the conventional fastener 60 shown in fig. 5.

In the present invention, the insertion hole portion of the first fastening member is formed so as to be capable of inserting both the second coupling portion and the opening/closing portion when the opening/closing portion of the second fastening member is brought into contact with the second coupling portion. This enables the first fastening member and the second fastening member to be more reliably coupled. Further, after the first fastening member and the second fastening member are coupled, the orientation of the second fastening member with respect to the first fastening member can be stabilized, and therefore, the decoration inversion at the time of the coupling operation of the mount is less likely to occur.

In the present invention, it is preferable that the second fastening member has a protruding piece portion protruding outward from an outer peripheral surface of the abutting portion, and the protruding piece portion is disposed so as to be close to the first fastening member and be separated from the first fastening member when the abutting portion abuts against the second coupling portion. By providing such a protruding piece portion in the second fastening member, the protruding piece portion can be easily hooked with a finger or a nail. Thus, the locked state of the opening/closing portion of the second fastening member can be easily released when the fastener is detached. In addition, the opening/closing portion can be easily rotated in a direction away from the second coupling portion. Therefore, the fastener detaching operation can be performed more simply and smoothly. Further, by disposing the projecting piece portion close to the first fastening member, deterioration of the touch of the fastening member due to the provision of the projecting piece portion can be suppressed.

In the present invention, the opening/closing portion includes a proximal end portion rotatably supported by the second coupling portion, a closing portion disposed between the proximal end portion and the abutting portion and closing the insertion/extraction opening portion from the outside, and a lateral covering portion integrally formed with the proximal end portion and the closing portion. In addition, in a side view of the second fastening member, the lateral covering portion of the opening/closing portion extends so as to protrude inward (inward peripheral side) from the proximal end portion and at least a part of the closing portion. The side covering portion of the opening/closing portion has a restricting edge portion formed obliquely or curvedly so that a space portion formed between a connecting portion where the closing portion and the abutting portion are straightly connected and the side covering portion in a side view state of the second fastening member assumes an angle of less than 90 °. Here, the connection portion of the closing portion and the abutting portion is a continuous portion (region) including a connection-side end portion of the closing portion connected to the abutting portion and a connection-side end portion of the abutting portion connected to the closing portion.

By providing such a side covering portion in the opening/closing portion, the second fastening member can be made more beautiful, and the appearance quality of the entire fastener can be improved. Further, the movement of the first fastening member with respect to the second fastening member (particularly, the movement of the connecting shaft portion of the first connecting portion connected to the second connecting portion) can be effectively restricted by the lateral covering portion (particularly, the end edge portion) of the opening/closing portion, and therefore, the connected state of the first fastening member and the second fastening member can be maintained more stably. Further, even when the engagement by the engagement portion of the second fastening member is easily disengaged, the first coupling portion of the first fastening member can be retained in the inner space portion of the second coupling portion by the lateral covering portion of the opening/closing portion, and therefore, the fastener can be more effectively prevented from being unintentionally separated.

[ description of the drawings ]

Fig. 1 is an enlarged side view schematically showing a main part of a garnish according to an embodiment of the present invention.

Fig. 2 is a schematic plan view of a main part of the garnish shown in fig. 1 when viewed from the outer peripheral surface (upper surface) side.

Fig. 3 is a perspective view schematically showing a state in which a first fastening member and a second fastening member of the fastener provided on the garnish of fig. 1 are separated.

Fig. 4 is a perspective view schematically showing a state where the first fastening member shown in fig. 3 is temporarily held on the second fastening member.

Fig. 5 is a side view showing a conventional fastener.

[ means for carrying out the invention ]

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the embodiments described below, and various modifications can be made as long as the present invention has substantially the same configuration and exhibits the same operational effects as the present invention.

Fig. 1 and 2 are a side view and a plan view schematically showing a main part of the garnish according to the present embodiment in an enlarged manner. Fig. 3 is a perspective view showing a state where a first fastening member and a second fastening member of a fastening member provided to the garnish are separated from each other, and fig. 4 is a perspective view showing a state where the first fastening member is temporarily held on the second fastening member.

In the following description, the direction of the fastener along the longitudinal direction of the linear member in the garnish (tennis bracelet) is set to the front-rear direction, and for example, in the present embodiment, when fig. 1 is viewed with the symbol (numeral) in the correct orientation, the left-right direction on the paper of fig. 1 is set to the front-rear direction of the fastener. In addition, the direction of the outer peripheral surface side (front surface side) orthogonal to the front-rear direction of the fastener and exposed to the outside of the fastener and the direction of the inner peripheral surface side (back surface side) facing the skin of the human body are set to the vertical direction, and in the present embodiment, the vertical direction of the paper surface of fig. 1 is the vertical direction of the fastener. In particular, in this case, the direction of the outer surface side exposed to the outside of the fastener is set to be upward, and the direction of the inner surface side facing the human skin of the fastener is set to be downward. In addition, the direction orthogonal to the front-back direction and the up-down direction of the fastener is set as the left-right direction, and in the present embodiment, the front-back direction of the paper of fig. 1 is the left-right direction of the fastener.

The tennis Bracelet (Bracelet/Line Bracelet)1 of the present embodiment is a glove, and the tennis Bracelet 1 includes an elongated chain-like linear member 5 constituting a main body portion of the Bracelet and fasteners 10 attached to both end portions of the linear member 5, and by connecting the fasteners 10, the whole tennis Bracelet 1 can be held in a ring shape.

The string-like member 5 of the tennis bracelet 1 includes a plurality of bracelet pieces 6 and a connecting portion 7 for connecting two adjacent bracelet pieces 6, and the connecting portion 7 is attached to the bracelet pieces 6 so as to be swingable with respect to the bracelet pieces 6. Each of the hand chain blocks 6 has a hand chain block body portion formed in a substantially rectangular tubular shape or a substantially cylindrical shape, and a jewel (diamond) not shown fixed to an outer surface portion (upper surface portion) of the hand chain block body portion. In the present invention, the form and structure of the linear member 5 are not particularly limited, and may be arbitrarily changed.

The fastener 10 of the tennis bracelet 1 is formed of metal, and the fastener 10 includes a first fastening member 11 attached to one end 5a of the string-like member 5 and a second fastening member 21 attached to the other end 5b of the string-like member 5 and capable of being coupled to and separated from the first fastening member 11.

The first fastening member 11 of the fastener 10 has: a first connecting portion 12 to which one end portion 5a of the string-like member 5 of the tennis bracelet 1 is fixed and connected, and a first connecting portion 13 integrally formed with the first connecting portion 12. The first connecting portion 12 includes a first connecting body portion 12a having a predetermined height dimension (dimension in the vertical direction) and a first connecting piece portion 12b extending in a thin plate shape from the first connecting body portion 12a in one of the front-rear directions. In this case, the first connecting body 12a has a height dimension larger than the bracelet strand body of the bracelet strand 6. The first connecting piece portion 12b is formed with a window portion that substantially corresponds to the shape of the internal space of the bracelet strand body portion provided in the bracelet strand 6, and that penetrates in the vertical direction.

In the first fastening member 11, the one end portion 5a of the linear member 5 is fixed to the first connecting piece portion 12b by welding such as brazing at a position apart from the first connecting body portion 12 a. In particular, in the present embodiment, the two fastener elements 6 of the wire member 5 are fixed to the first connecting piece portion 12b of the first connecting portion 12, so that the first fastening member 11 can be easily gripped with fingers. In the present invention, the method of connecting the first fastening member 11 and the one end portion 5a of the linear member 5 is not particularly limited, and for example, the first fastening member 11 and the one end portion 5a of the linear member 5 may be connected by bonding with an adhesive, or the first fastening member 11 and the one end portion 5a of the linear member 5 may be connected via a circular loop. The first connecting portion 12 of the first fastening member 11 may be formed to have a size for fixing one hand chain block 6 or three or more hand chain blocks 6, instead of having a size for fixing two hand chain blocks 6 as described above. The first tightening member 11 may be integrally formed at one end of the linear member 5.

The first connecting portion 13 extends in the front-rear direction from a substantially central portion in the vertical direction of a surface of the first connecting main body portion 12a opposite to the first connecting piece portion 12 b. The first connecting portion 13 is provided with an insertion hole portion 14 penetrating in the vertical direction, and the first connecting portion 13 is formed in a shape of a partial circle or a partial ellipse when viewed from above (outer circumferential surface side) (see fig. 2). A part of the first coupling portion 13 is a coupling column 13a, and is hooked and held to a second coupling portion 23, described later, of the second fastening member 21 when the first fastening member 11 and the second fastening member 21 are coupled.

In the present embodiment, the first connecting portion 13 is formed such that the cross section of the connecting column 13a is circular, but the cross section may be formed to have another shape such as a substantially square shape in the present invention. The first connecting portion 13 may be formed to have a substantially コ -shaped or substantially U-shaped shape, or any other shape when viewed from above (outer peripheral surface side).

When the first fastening member 11 and the second fastening member 21 are coupled, the insertion hole portion 14 of the first coupling portion 13 is opened such that: the size of the second fastening member 21 is such that two members, which will be described later, of the second connecting portion 23 (particularly, the distal end pillar portion 27b of the second connecting portion 23) and the opening/closing portion 31 (particularly, the contact portion 34 of the opening/closing portion 31) can be inserted therethrough.

In the present embodiment, the insertion hole portion 14 is opened such that: the size of the contact portion 34 through which the later-described protruding piece portion 35 of the second fastening member 21, the second connecting portion 23, and the opening/closing portion 31 can be inserted is such that the first fastening member 11 connected to the second fastening member 21 can move as indicated by the imaginary line arrow. Accordingly, after the first fastening member 11 and the second fastening member 21 are coupled, the first coupling portion 13 can be made less likely to be hooked on the second fastening member 21, and thus, for example, the first coupling portion 13 can be prevented from being hooked on the protruding piece portion 35 and the opening/closing portion 31, which will be described later, of the second fastening member 21 can be prevented from being rotated in the opening direction.

The second fastener 21 includes a second connecting portion 22 fixedly connected to the other end 5b of the linear member 5 of the tennis bracelet 1, a second body portion 24 formed continuously and integrally from the second connecting portion 22, a second linking portion 23 extending from the second body portion 24 in a direction away from the second connecting portion 22 (in a direction approaching the first fastener 11) and having a hook-like shape, an opening/closing portion 31 rotatably disposed on the second body portion 24, and a locking portion 25 for maintaining the state in which the opening/closing portion 31 is in contact with the second linking portion 23. That is, in the second fastening member 21 of the present embodiment, the second body portion 24 that rotatably supports the opening/closing portion 31 is provided on the side closer to the other end portion 5b of the linear member 5 (the side away from the first fastening member 11) than the distal end portion of the second coupling portion 23 that is first inserted into the insertion hole portion 14 of the first fastening member 11.

In this case, the second connection portion 22 is formed by a rectangular frame-shaped thin plate piece having an open window portion at a substantially central position, and the other end portion 5b of the linear member 5 is fixed to the second connection portion 22 by welding or the like. In the present invention, the method of connecting the second fastening member 21 to the other end 5b of the linear member 5 is the same as the method of connecting the first fastening member 11, and is not particularly limited.

The second body portion 24 includes a body base 26 continuous with the second connecting portion 22 and abutting against a part of the opening/closing portion 31 to restrict the rotation range of the opening/closing portion 31, and a support portion 28 integrally formed on the body base 26 and supporting the opening/closing portion 31. The main body base 26 has the same dimension (width dimension) in the left-right direction as the second connection portion 22.

In the present embodiment, the storage recess 26a is provided in the center portion in the width direction (left-right direction) of the main body base 26 in correspondence with the position of a tail portion 32b of the opening/closing portion 31, which will be described later. The housing recess 26a abuts against and houses a part of the opening/closing portion 31 that rotates in the opening direction such that the rotation range of the opening/closing portion 31 is substantially 90 °. Here, as shown in fig. 1, the range of rotation of the opening/closing portion 31 is a range from a state in which the opening/closing portion 31 (particularly, the tail portion 23b) is locked by the locking portion 25 to a state in which the opening/closing portion 31 abuts against the main body base 26 as shown in fig. 3 and 4.

The support portion 28 of the second body portion 24 is formed to be smaller than the width dimension of the body base portion 26 in the left-right direction and to protrude in a thin plate shape from the body base portion 26. A bearing recess into which a rotation shaft 32a of the opening/closing portion 31, which will be described later, is inserted is formed in the support portion 28, and the opening/closing portion 31 is rotatably supported by the second body portion 24 by engagement of the bearing recess of the support portion 28 with the rotation shaft 32a of the opening/closing portion 31.

The second coupling portion 23 is formed by a hook-shaped coupling body portion 27 extending from the support portion 28 of the second body portion 24 in a direction opposite to the second coupling portion 22, and an insertion/removal opening portion 29 opened so that the coupling post 13a of the first coupling portion 13 can pass therethrough is formed between the distal end portion of the coupling body portion 27 and the support portion 28.

The width dimension of the coupling body portion 27 in the left-right direction is smaller than the second connection portion 22 and is formed to be the same size as the support portion 28. The connecting body portion 27 includes a body pillar portion 27a extending substantially straight in the front-rear direction from the second body portion 24, and a distal end pillar portion 27b extending from the body pillar portion 27a via a bent portion (a waisted portion). In the side view of the second fastening member 21, the distal end pillar portion 27b extends in an arc shape while being curved from the curved portion toward the upper end portion of the support portion 28.

An inner space 30 capable of accommodating a part of the first coupling portion 13 (the coupling post 13a) is formed in the coupling body portion 27 so as to communicate with the insertion/removal opening portion 29 between the body post portion 27a and the distal end post portion 27 b. Further, a locking recess 27d is recessed in the left-right direction in an outer peripheral surface portion of a base end portion (an end portion on a side close to the bent portion) of the distal end pillar portion 27 b. A part of the opening/closing portion 31 (a locked projection 36 of the opening/closing portion 31, which will be described later) is fitted into the locking recess 27d, and the opening/closing portion 31 is locked so as not to move. In this case, the locking recess 27d is formed in a concave shape with the center portion being most recessed.

The length of the tip pillar portion 27b formed in the circular arc shape is set such that the central angle of the circular arc is 135 ° or more, and preferably 180 ° or more. The distal pillar portion 27b is formed to a length that does not reach the position of the lateral covering portion 37, so that when the fastener 10 is viewed from one of the left and right sides in a state where the contact portion 34 of the opening/closing portion 31 is in contact with the second coupling portion 23 (see fig. 1), the distal pillar portion 27b is not hidden inside the lateral covering portion 37 with respect to the later-described lateral covering portion 37 of the opening/closing portion 31, and a gap G is formed between the distal pillar portion 27b and the later-described limit edge portion 37a of the lateral covering portion 37. In this case, the length of the distal pillar portion 27b is set to: in the state of fig. 1, the minimum value of the gap G is set to a size that does not allow the connecting column 13a of the first connecting portion 13 to be inserted therethrough. That is, the gap G is formed smaller than the thickness of the connecting column 13a of the first connecting portion 13 (particularly, the diameter of the circular cross section of the connecting column 13 a).

The opening/closing portion 31 of the second fastening member 21 includes: a base end portion 32 having a rotation shaft portion 32a, the rotation shaft portion 32a being pivotally supported by a bearing recess portion provided in the support portion 28 of the second body portion 24; a closing part 33 extending from the proximal end part 32; an abutting portion 34 formed in a substantially circular arc shape and further extending from the closing portion 33; a protruding piece portion 35 protruding outward from the bent portion of the abutting portion 34; a locked projection 36 formed at the distal end of the contact portion 34 and inserted into the locking recess 27d of the second coupling portion 23; and a thin plate-shaped lateral covering portion 37 extending from the base end portion 32 and the closing portion 33 to a position on the second coupling portion 23 in the lateral direction of the body pillar portion 27a in the contact state of the contact portion 34.

A base end portion 32 of the opening/closing portion 31 is provided with a storage portion (storage space portion) for storing the support portion 28 of the second body portion 24, a rotation shaft portion 32a protruding in the left-right direction toward the storage portion, and a tail portion 32b which abuts against a bottom surface of the storage recess portion 26a provided in the second body portion 24 to stop rotation of the opening/closing portion 31. In this case, the tail portion 32b is arranged at the upper end portion of the base end portion 32 in a side view of the second fastening member 21 and has a tongue-like shape protruding obliquely upward. By providing such a tail portion 32b to the opening/closing portion 31, for example, when the opening/closing portion 31 is rotated in the opening direction, the tail portion 32b can be easily pressed with a finger or the like, and thus the rotation operation of the opening/closing portion 31 can be more easily performed.

The closing portion 33 of the opening/closing portion 31 extends substantially linearly from the base end portion 32, and when the contact portion 34 is brought into contact with the second coupling portion 23, the closing portion 33 closes from above together with a part of the base end portion 32 to close the insertion/extraction opening portion 29 of the second fastening member 21. The contact portion 34 of the present embodiment is formed to extend from the closing portion 33 in a substantially arc shape so that the contact portion 34 can contact, preferably be in surface contact with, the outer peripheral surface of at least a part of the distal end pillar portion 27b of the second connecting portion 23. In the present invention, for example, when the second coupling portion 23 has a different shape, the contact portion 34 may be formed to extend from the closing portion 33 in a substantially L shape in accordance with the shape of the second coupling portion 23.

The projecting portion 35 projects obliquely upward outward from the portion of the contact portion 34 where the bending starts. In this case, as shown in fig. 1, the protruding piece 35 is disposed at a position relatively close to the first connecting body 12a of the first fastening member 11 in a state where the first fastening member 11 and the second fastening member 21 are coupled to each other and in a state where the abutting portion 34 of the second fastening member 21 abuts against the second coupling portion 23. In particular, in the case of the present embodiment, in a side view of the second fastening member 21, the abutment portion 34 is disposed on a side closer to the first fastening member 11 (a side farther from the second connection portion 22) than the distal end position of the substantially arc-shaped distal end pillar portion 27b in the front-rear direction. This can prevent the fastener 10 from deteriorating in the tactile sensation due to the provision of the protruding piece portion 35. When the first fastening member 11 and the second fastening member 21 are held substantially linearly in a side view, the protruding piece portion 35 is provided apart from the first connecting body portion 12a so that a gap is formed between the protruding piece portion 35 of the second fastening member 21 and the first connecting body portion 12 a.

The protruding piece 35 is formed short so as to be inserted into the insertion hole 14 provided in the first fastening member 11 together with the second connecting portion 23 and the contact portion 34 of the opening/closing portion 31. For example, in the present embodiment, in a side view of the second fastening member 21, the protruding length of the protruding portion 35 protruding from the abutment portion 34 is formed to be substantially the same as the thickness of the abutment portion 34 (the interval between the inner peripheral surface and the outer peripheral surface) or to be shorter than the thickness of the abutment portion 34.

An engaged projection 36 bulging toward the inner peripheral side of the substantially circular arc-shaped (or substantially L-shaped) abutting portion 34 is formed at the tip end portion of the abutting portion 34 in a size insertable into the engaging recess 27d of the second coupling portion 23. The locking portion 25 is constituted by a locked projection 36 provided on the opening/closing portion 31 and a locking recess 27d provided on the second coupling portion 23. The locking portion 25 maintains the contact state in which the opening/closing portion 31 is locked to the second coupling portion 23 when the contact portion 34 contacts the second coupling portion 23. In the present invention, the form of the locking portion provided to maintain the abutting state of the abutting portion 34 is not particularly limited, and the locking portion may be formed by another form such as a concave portion or a convex portion that engages with each other, for example, in the lateral covering portion 37 and the body pillar portion 27a of the second coupling portion 23.

In this case, the engaged projection 36 provided on the opening/closing portion 31 is formed to protrude in a spherical shape in a direction orthogonal to the rotational direction of the opening/closing portion 31 (in other words, in a direction orthogonal to the distal end portion of the substantially arc-shaped abutting portion 34). That is, in the side view of the second fastening member 21, the protruding surface of the engaged projection 36 is formed in an arc shape. In addition, in the side view of the second fastening member 21, the engaged protrusion 36 of the present embodiment is integrally provided on the distal end portion of the contact portion 34 such that the bulging curved surface of the engaged protrusion 36 is a curved surface smoothly continuing to the distal end surface of the contact portion 34. This enables the protruding stop portion 36 of the abutment portion 34 to be smoothly inserted into and removed from the locking recess 27 d.

As described above, the opening/closing section 31 of the present embodiment is provided with the pair of left and right side covering sections 37. Each lateral covering portion 37 is formed to extend inward from the proximal end portion 32 and the closing portion 33, and covers a part of the inner space portion 30 formed in the second coupling portion 23 and the insertion/extraction opening portion 29 from one lateral side when the opening/closing portion 31 is closed with respect to the second coupling portion 23 (in other words, when the contact portion 34 of the opening/closing portion 31 is brought into contact with the second coupling portion 23). In this case, the lateral covering portion 37 is formed in a size that overlaps at least a part of the body pillar portion 27a of the second coupling portion 23 in a side view of the second fastening member 21 when the opening/closing portion 31 is closed. In particular, in the present embodiment, the side covering portion 37 is formed in a size such that its lower end edge overlaps with the lower end edge of the body pillar portion 27a in the second coupling portion 23. This improves the appearance of the second fastening member 21, and improves the appearance of the fastener 10 itself.

The side covering portion 37 has a restricting end edge portion 37a that extends from the closing portion 33 while being obliquely bent (or inclined) when the opening/closing portion 31 is closed, so that a space portion formed between the side covering portion 37 and a connecting portion between the closing portion 33 and the abutting portion 34 when viewed from a side of the second fixing member 21 is at an angle of less than 90 °. In particular, in the present embodiment, in the state shown in fig. 1, the side covering portion 37 is formed so that the minimum value of the gap G formed between the distal pillar portion 27b and the limiting end edge portion 37a of the distal pillar portion 27b of the second connecting portion 23 is not as large as the size through which the connecting pillar 13a of the first connecting portion 13 is inserted.

In the tennis bracelet 1 having the fastener 10 of the present embodiment described above, when the first fastening member 11 and the second fastening member 21 connected to the one end portion 5a of the linear member 5 are coupled from a state in which the first fastening member 11 and the second fastening member 21 connected to the other end portion 5b of the linear member 5 are separated from each other, first, as shown in fig. 3, the opening/closing portion 31 of the second fastening member 21 is rotated so as to be separated from the coupling main body portion 27 of the second coupling portion 23, and the insertion/extraction opening portion 29 of the second fastening member 21 is opened. The operation of rotating the opening/closing portion 31 of the second fastening member 21 can be easily performed with one hand. The opening/closing unit 31 may be rotated with both hands.

Next, the first fastening member 11 is brought close to the second fastening member 21 held on the wrist, for example, and as shown by the imaginary line in fig. 4, the coupling post 13a of the first coupling portion 13 of the first fastening member 11 is inserted into the open insertion/extraction opening 29 of the second fastening member 21, and the coupling post 13a of the first coupling portion 13 is moved from the insertion/extraction opening 29 to the inner space 30 surrounded by the trunk portion 27a and the tip post portion 27b of the second coupling portion 23 while the tip post portion 27b of the second coupling portion 23 is inserted through the insertion hole portion 14 provided in the first coupling portion 13 of the first fastening member 11. More preferably, the connection post 13a of the first connection portion 13 is brought into contact with the proximal end portion of the distal post portion 27b of the second connection portion 23.

This allows the first fastening member 11 to be hooked on the second fastening member 21 and temporarily held. In this way, the first fastening member 11 can be easily temporarily held with one hand. In the case of the present embodiment, since the first coupling portion 13 of the first fastening member 11 has a shape of a part having a circular shape (or a part having an elliptical shape) in plan view as described above, even when the first fastening member 11 is inclined, for example, with respect to the front-rear direction, the operation of inserting the first fastening member 11 into the insertion/extraction opening portion 29 of the second fastening member 21 and temporarily holding the same in the second coupling portion 23 can be easily and smoothly performed.

In the present embodiment, when temporarily holding the first fastening member 11, the short distal end pillar portion 27b of the second coupling portion 23 may be inserted into the insertion hole portion 14 of the first coupling portion 13, and thus, for example, as in the conventional fastening device 60 shown in fig. 5, it is not necessary to insert the short distal end pillar portion 27b into the entire length of the opening/closing portion 62 d. In the present embodiment, the distal end pillar portion 27b of the second connecting portion 23 is formed to have substantially the same thickness as a whole. Therefore, when the distal end pillar portion 27b of the second coupling portion 23 is inserted into the insertion hole portion 14 of the first coupling portion 13, the first coupling portion 13 of the first fastening member 11 is less likely to be caught by the distal end pillar portion 27 b. Therefore, even with one-handed operation, the first fastening member 11 can be temporarily held smoothly by the second fastening member 21.

Further, as shown in fig. 4, by temporarily holding the first fastening member 11 to the second fastening member 21, the first fastening member 11 is not easily detached from the second fastening member 21 even if the first fastening member 11 is separated from the finger. Further, since the first tightening member 11 and the second tightening member 21 are pulled in the direction of separating from each other by the weight of the linear member 5, the temporarily held state of the first tightening member 11 can be easily and stably maintained.

After the first fastening member 11 is temporarily held, the opening/closing portion 31 of the second fastening member 21 is rotated so as to approach the second coupling portion 23 (coupling body portion 27), and the arc-shaped contact portion 34 of the opening/closing portion 31 is brought into contact with the second coupling portion 23. In this way, the operation of rotating the opening/closing portion 31 of the second fastening member 21 can be easily performed by one hand.

As described above, the closing portion 33 of the opening/closing portion 31 closes the insertion/removal opening 29 of the second fastening member 21 from above by bringing the contact portion 34 into contact with the second coupling portion 23. At the same time, the lateral covering portions 37 of the opening/closing portion 31 cover the inner space portion 30 of the second coupling portion 23 from the left and right sides, and thus the region in which the coupling column 13a of the first fastening member 11 can move in the inner space portion 30 can be restricted (reduced). Thereby, the first fastening member 11 and the second fastening member 21 are coupled as shown in fig. 1, and the tennis bracelet 1 can be held in a ring shape.

At this time, by bringing the contact portion 34 of the opening/closing portion 31 of the second fastening member 21 into contact with the second coupling portion 23, the contact portion 34 can be inserted from above into the insertion hole portion 14 formed in the first coupling portion 13 of the first fastening member 11. The engaged protrusion 36 provided at the distal end of the opening/closing portion 31 can be inserted into the engaging recess 27d provided in the second coupling portion 23 and engaged therewith.

In this way, not only the distal-end column portion 27b of the second coupling portion 23 but also the contact portion 34 of the opening/closing portion 31 can be inserted into the insertion hole portion 14 of the first fastening member 11, whereby the first fastening member 11 and the second fastening member 21 can be coupled more reliably. Further, by locking the engaged projection 36 provided on the opening/closing portion 31 to the second coupling portion 23, the state in which the contact portion 34 of the opening/closing portion 31 is in contact with the second coupling portion 23 can be maintained, and the coupled state of the first fastening member 11 and the second fastening member 21 can be stably maintained.

Further, as in the present embodiment, the operation of coupling the first fastening member 11 and the second fastening member 21 is performed by rotating the opening/closing portion 31 of the second fastening member 21, and thus the orientation of the upper surface side (front surface side) and the lower surface side (back surface side) of the fastener 10 can be easily confirmed or unconsciously grasped at the time of the coupling operation. As a result, the tennis bracelet 1 is less likely to be worn upside down, and the accessory can be urged to be worn in the correct orientation.

Further, as shown in fig. 1, when the first fastening member 11 and the second fastening member 21 are coupled, the movable range of the coupling column 13a of the first fastening member 11 in the inner space portion 30 of the second fastening member 21 can be appropriately restricted by providing the left and right side covering portions 37 of the second fastening member 21 (particularly, by providing the inclined restricting end edge portions 37a in the side covering portions 37). The gap G formed between the distal end pillar portion 27b of the second fastening member 21 and the regulating end edge portion 37a is formed to have a size such that the connecting pillar 13a of the first connecting portion 13 is not inserted therethrough, as described above. This allows the coupling column 13a of the first fastening member 11 to stably stay in the inner space 30 of the second fastening member 21. In addition, in the case of the present embodiment, since the first fastening member 11 and the second fastening member 21 to be coupled receive a tensile force in a direction of separating from each other due to the weight of the linear member 5, a structural effect can be obtained in which the state in which the coupling post 13a of the first fastening member 11 and the distal end post portion 27b of the second fastening member 23 are in contact with each other is easily maintained.

As a result, for example, it is possible to effectively prevent the connecting column 13a of the first fastening member 11 from pressing the opening/closing portion 31 of the second fastening member 21 in the opening direction due to excessive force for some reason and thereby rotating the opening/closing portion 31. Therefore, the coupled state of the first fastening member 11 and the second fastening member 21 can be maintained more reliably, and the first fastening member 11 and the second fastening member 21 can be prevented from easily coming off.

Further, even when the opening/closing portion 31 is rotated to a position shown by an imaginary line shown in fig. 1, for example, by an unexpected external force, the opening/closing portion 31 is not further opened largely by being pulled by the linear member 5. The second fastening member 21 of the present embodiment is provided with the pair of left and right side covering portions 37 as described above. Therefore, the side covering portion 37 blocks the insertion/removal opening portion 29 of the second fastening member 21, and the connecting column 13a of the first fastening member 11 can be prevented from being ejected from the inner space portion 30, so that the fastening tool 10 can be prevented from being easily detached.

On the other hand, as shown in fig. 1, when the first fastening member 11 and the second fastening member 21 are separated from each other from the state in which the first fastening member 11 and the second fastening member 21 are coupled to each other, first, the protruding piece portion 35 of the second fastening member 21 is hooked with a finger or a nail to rotate the opening/closing portion 31 of the second fastening member 21 so as to be separated from the second coupling portion 23. This opens the insertion opening 29 of the second fastening member 21. The operation of rotating the opening/closing portion 31 can be easily performed by one hand.

Thereafter, the first fastening member 11 is held by the fingers, and the coupling post 13a of the first fastening member 11 is pulled out from the inner space 30 of the second fastening member 21 through the insertion/extraction opening 29, whereby the first coupling portion 13 of the first fastening member 11 is detached from the second coupling portion 23 of the second fastening member 21. Thus, the first fastening member 11 and the second fastening member 21 can be easily and smoothly separated with only one hand.

According to the fastener 10 of the present embodiment, the operation of coupling and separating the first fastening member 11 and the second fastening member 21 can be easily and smoothly performed with only one hand. Therefore, the fastener 10 of the present embodiment can greatly improve the operability of the fastener 10 as compared with, for example, a conventional snap-type fastener or a plug-type fastener. Therefore, even for a person who does not respond to the operation of the conventional fastener, for example, as long as the tennis bracelet 1 or other accessory using the fastener 10 of the present embodiment is a suit, the fastening operation and the detaching operation of the fastener 10 can be performed easily, and therefore, the accessory can be used more conveniently.

Further, since the fastener 10 of the present embodiment is formed with a simple structure that is easy to form, it can be applied not only to the tennis bracelet 1, but also to accessories such as necklaces, pendants, and ankle rings (anklets). In particular, in the present invention, the first fastening member 11 and the second fastening member 21 of the fastener 10 can be easily set to be small in size, or the first fastening member 11 and the second fastening member 21 can be easily set to be long or short along the length of the linear member 5. This makes it possible to greatly expand options of the fastener 10 that can be used for a garnish, and as a result, design and aesthetic appearance of the garnish can be more effectively expressed.

[ description of symbols ]

1 tennis hand chain (bracelet)

5 Linear Member

5a one end part

5b another end portion

6 bracelet block

7 connecting part

10 fastener

11 first fastening part

12 first connection part

12a first connecting body part

12b first connecting piece part

13 first connecting part

13a connecting column

14 part of inserting hole

21 second fastening part

22 second connection part

23 second connecting part

24 second body part

25 locking part

26 base of main body

26a accommodating recess

27 connecting the main body part

27a trunk portion

27b top post part

27d locking recess

28 support part

29 inserting and extracting opening part

30 inner space part

31 opening and closing part

32 basal end portion

32a rotating shaft part

32b tail part

33 closure part

34 abutting part

35 protruding piece part

36 are locked with the protruding part

37 lateral covering part

37a limit end edge part

A gap formed between the G-top pillar part and the lateral covering part

Claims (5)

1. A fastener for jewelry, having a first fastening member (11) arranged at one end (5a) of a linear member (5) of a jewelry (1), a second fastening member (21) arranged at the other end (5b) of the linear member and capable of being coupled to and decoupled from the first fastening member (11), the fastener (10) for jewelry being characterized in that,

the first fastening member (11) has: a first connecting portion (12) connected to the one end portion (5a) of the linear member (5); a first connecting portion (13) that is formed integrally with the first connecting portion (12) and is connected to the second fastening member (21),

an insertion hole part (14) through which a part of the second fastening member (21) is inserted is provided in the first connecting part (13),

the second fastening member (21) has: a second connecting portion (22) connected to the other end (5b) of the linear member (5); a second body portion (24) continuously formed integrally from the second connection portion (22); a second coupling part (23) extending from the second body part (24) in a direction away from the second coupling part (22) and having a hook-like shape coupled to the first coupling part (13); an insertion/removal opening (29) which communicates with an inner space (30) of the second coupling section (23) and through which a part of the first coupling section (13) can pass; an opening/closing section (31) rotatably supported by the second body section (24) so as to be capable of opening and closing the insertion/extraction opening section (29), and including a substantially L-shaped or substantially arc-shaped contact section (34) that contacts the outer peripheral surface of the second connection section (23); and a locking part (25) which locks the opening/closing part (31) when the opening/closing part (31) abuts against the second connecting part (23) to maintain the abutting state.

2. The fastener for jewelry of claim 1, wherein,

the locking part (25) is provided with a locking concave part (27d) which is concavely arranged on the outer peripheral surface of the second connecting part (23) and a locked protruding part (36) which is arranged on the contact part (34) and is inserted into the locking concave part (27 d).

3. The fastener for jewelry as claimed in claim 1 or 2,

when the opening/closing section (31) abuts against the second connecting section (23), the second connecting section (23) and the opening/closing section (31) are inserted into the insertion hole section (14) of the first fastening member (11).

4. The fastener for jewelry according to any one of claims 1 to 3,

the second fastening member (21) has a protruding piece (35) protruding outward from the outer peripheral surface of the contact portion (34),

when the abutting portion (34) abuts against the second coupling portion (23), the protruding piece portion (35) approaches the first fastening member (11).

5. The fastener for jewelry according to any one of claims 1 to 4,

the opening/closing unit (31) has: a base end portion (32) rotatably supported by the second connection portion (23); a closing section (33) which is disposed between the base end section (32) and the contact section (34) and closes the insertion/removal opening section (29); and a lateral covering portion (37) formed integrally with the base end portion (32) and the closing portion (33),

the lateral covering portion (37) has a restricting end edge portion (37a), the restricting end edge portion (37a) extends so as to protrude inward from at least a part of the base end portion (32) and the closing portion (33) in a side view of the second fastening member (21), and the restricting end edge portion (37a) is formed obliquely or curved so that a space portion formed between the restricting end edge portion (37a) and a connecting portion of the closing portion (33) and the abutting portion (34) has an angle of less than 90 degrees.