BUCKLE, AND METHOD OF DECOUPLING FEMALE AND MALE PARTS OF BUCKLE

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001]This application claims a benefit of Japanese Patent Application No. 2024-205006 filed in Japan on Nov. 25, 2024, the entire content of which is hereby incorporated by reference.

FIELD OF THE DISCLOSURE

[0002]The present disclosure relates to a buckle, and a method of decoupling female and male parts of buckle.

PRIOR ART

[0003]In general, all-purpose buckles used for clothing, bags, shoes, and the like are easily unlocked through pinching operation between a thumb and a forefinger. However, unlike such all-purpose buckles, there is another need for buckles designed to impede easier decoupling of male and female parts after they are coupled. For example, U.S. Pat. No. 11,064,771 discloses a buckle designed to impose an operational burden for decoupling male and female parts on a user to pull a cord so as to operate a leaf spring for unlocking (see FIGS. 9A and 16 of the same document). Just for a reference, FIG. 9A of the same document illustrates a locked state in which a protrusion is engaged with an opening of the leaf spring inside a channel.

BACKGROUND

[0004]In the buckle of U.S. Pat. No. 11,064,771, there is a possibility that, if it became impossible to pull the cord for any reason (e.g. the cord was cut or lost), the buckle would be prevented from being released. In such a situation, as the buckle is manufactured to have a higher stiffness in general, it would be quite hard to release the buckle. In view of such a non-limiting exemplary technical problem, the present inventors have discovered a new challenge in enabling temporal releasing of a buckle which is designed to be unlocked through a limited method.

SUMMARY

[0005]A buckle according to an aspect of the present disclosure includes: a female part including a female portion in which a female channel and an aperture are formed, the female channel having channel ends on both sides in a width direction of the female part, and the aperture opening the female channel forwardly of the female part; a male part including a male portion and a main body interconnected to the male portion rearwardly of the male part, the male portion being inserted and retained in the female channel of the female portion, and the male portion including a leaf spring which is elastically bendable and deformable responsive to external operation using a cord. Elastic deformation of the leaf spring enables engagement between an engagement protrusion and a protrusion-accommodating portion, thereby preventing the male portion from moving inside and along the female channel; and the engagement protrusion is releasable from the protrusion-accommodating portion as the leaf spring bends and deforms responsive to the external operation using the cord. The female portion has at least one access-window through which external force is applicable directly or indirectly to the leaf spring for releasing the engagement protrusion from the protrusion-accommodating portion in a state where the engagement protrusion and the protrusion-accommodating portion are engaged so as to prevent the male portion from moving inside and along the female channel.

[0006]In some embodiments, the leaf spring has an external face and an internal face by which a plate thickness of the leaf spring is defined, the engagement protrusion being arranged on the external face of the leaf spring, and the protrusion-accommodating portion being formed in the female portion. Number of the engagement protrusion may be one, or two or more. Number of the protrusion-accommodating portion may be one, or two or more. The engagement protrusion may be positioned at a center in the width direction of the male part. The protrusion-accommodating portion may be positioned at a center in the width direction of the female part.

[0007]In some embodiments, the protrusion-accommodating portion and the access-window are situated at a same location in the width direction of the female portion so as to form a first opening that serves as both the protrusion-accommodating portion and the access-window. The first opening is formed to penetrate the female portion from the external surface of the female portion to the female channel. The external force is indirectly applicable to the leaf spring via the engagement protrusion situated in the first opening in the engaged state of the engagement protrusion and the protrusion-accommodating portion. The first opening may be positioned at a center in the width direction of the female portion.

[0008]In some embodiments, the first opening is defined between left and right wall surfaces which are opposed to each other with an interspace in the width direction of the female portion, the interspace between the left and right wall surfaces being 1 cm or less.

[0009]In some embodiments, the female portion includes a lower plate, an upper plate and an interconnection plate via which the lower plate and the upper plate are interconnected. The first opening may penetrate each of (i.e. every of) the lower plate, the upper plate and the interconnection plate. The female channel is open by the first opening at least in three directions of a lower side, upper side and rear side.

[0010]In some embodiments, the engagement protrusion includes a lower protrusion and an upper protrusion which are opposed to each other with an interspace in an up-down direction. Both the lower protrusion and the upper protrusion may be accommodated in the first opening without protruding from the first opening.

[0011]In some embodiments, the interconnection plate is provided with at least one guide protrusion that guides the male portion moving along the female channel. The guide protrusion and the lower plate are arranged to form a lower groove therebetween into which the lower protrusion is inserted, and the guide protrusion and the upper plate are arranged to form an upper groove therebetween into which the upper protrusion is inserted.

[0012]In some embodiments, the interconnection plate has at least one sloped surface on which the engagement protrusion slides to bend the leaf spring as the male portion is inserted into the female channel.

[0013]In some embodiments, the leaf spring has a cord-coupled-portion to which the cord is coupled. The cord-coupled-portion includes an internal passage through which the cord passes, a pillar about which the cord is wound, and a cord-retaining portion that presses and retains the cord. The internal passage reaches the external face of the leaf spring to form a second opening in the external face, the cord-retaining portion and the pillar being arranged in this order away from the second opening of the leaf spring.

[0014]In some embodiments, the female portion does not have a protrusion that protrudes into the second opening formed by the internal passage and formed in the external face of the leaf spring.

[0015]In some embodiments, the main body has a channel for cord through which the cord is allowed to extend away from the cord-coupled-portion rearwardly of the male part. The main body includes at least one passage for belt with which the channel for cord is in spatial communication, and a rear rod that defines the passage for belt from a rear side of the male part. The front surface of the rear rod includes a sloped surface that is slanted across substantially entire thickness of the rear rod.

[0016]In some embodiments, the lower plate and the upper plate are respectively provided with a lower stopper and an upper stopper so that the male portion is prevented from exiting the female channel via the aperture.

[0017]A method according to another aspect of the present disclosure is related to a method for decoupling the male part and the female part in any one of the above noted buckles. The method includes: inserting a bar-like member into the access-window to apply an external force directly or indirectly to the leaf spring so that the engagement protrusion is released from the protrusion-accommodating portion; and allowing the male portion to exit the female channel through lateral pulling.

[0018]The leaf spring has an external face and an internal face by which a plate thickness of the leaf spring is defined, the engagement protrusion being arranged on the external face of the leaf spring, and the protrusion-accommodating portion being formed in the female portion. The protrusion-accommodating portion and the access-window are situated at a same location in the width direction of the female portion so as to form a first opening that serves as both the protrusion-accommodating portion and the access-window. The first opening is formed to penetrate the female portion from the external surface of the female portion to the female channel. The external force is indirectly applicable to the leaf spring via the engagement protrusion situated in the first opening in the engaged state of the engagement protrusion and the protrusion-accommodating portion.

[0019]According to an aspect of the present disclosure, there is provided a buckle that enables temporal releasing thereof.

BRIEF DESCRIPTION OF DRAWINGS

[0020]FIG. 1 is a perspective view of a buckle according to an aspect of the present disclosure.

[0021]FIG. 2 is an exploded perspective view of the buckle.

[0022]FIG. 3 is an exploded perspective view of the buckle viewed from a different viewpoint from that of FIG. 2.

[0023]FIG. 4 is an exploded perspective view of the buckle, showing one transitional state while the male and female parts are being coupled.

[0024]FIG. 5 is a top view of the buckle in a state where male and female parts are separated.

[0025]FIG. 6 is a side view of the buckle in a state where male and female parts are separated.

[0026]FIG. 7 is a side view of the buckle in a state where male and female parts are coupled.

[0027]FIG. 8 is a vertical cross-sectional schematic view of the male part taken along alternate long and short dash lines X8-X8 in FIG. 5.

[0028]FIG. 9 is a horizontal cross-sectional schematic view of the male part taken along alternate long and short dash lines X9-X9 in FIG. 6.

[0029]FIG. 10 is a front view of the male part.

[0030]FIG. 11 is a schematic diagram showing a process in which a male portion of the male part is inserted into a female channel of a female portion of the female part so that an engagement protrusion and a protrusion-accommodating portion are engaged with each other.

[0031]FIG. 12 is a schematic diagram showing a process in which the male portion is inserted into the female channel so that the engagement protrusion and the protrusion-accommodating portion are engaged with each other.

[0032]FIG. 13 is a schematic diagram showing a process in which the male portion is inserted into the female channel so that the engagement protrusion and the protrusion-accommodating portion are engaged with each other.

[0033]FIG. 14 is a horizontal cross-sectional schematic view of the female part taken along alternate long and short dash lines X14-X14 in FIG. 7. FIG. 14 is illustrated in accordance with a precision based on a product blueprint.

[0034]FIG. 15 is a horizontal cross-sectional schematic view showing a state in which a female part is pulled by a cord rearwardly with a leaf spring being bent in the same direction, forming a slight clearance between the leaf spring and a guide protrusion.

[0035]FIG. 16 is a horizontal cross-sectional schematic view showing a state in which the leaf spring is bent rearwardly of the female part by the cord so that the engagement protrusion exits the protrusion-accommodating portion. The engagement protrusion moves out from the protrusion-accommodating portion and can move away from the protrusion-accommodating portion leftward or rightward.

[0036]FIG. 17 is a vertical cross-sectional schematic view taken at the center in a width direction of the buckle in a state where the male part and the female part are coupled. FIG. 17 is illustrated in accordance with a precision based on a product blueprint.

[0037]FIG. 18 is a top view of a buckle according to another aspect of the present disclosure.

[0038]FIG. 19 is a vertical cross-sectional schematic view of the buckle taken along alternate long and short dash lines A-A in FIG. 18.

DETAILED DESCRIPTION

[0039]Hereinafter, non-limiting embodiments and features of the present invention would be discussed with reference to drawings. A skilled person would be able to combine respective embodiments and/or respective features without requiring excess description, and would appreciate synergistic effects of such combinations. Overlapping description among the embodiments is basically omitted. Referenced drawings aim mainly for describing inventions and are simplified for the sake of convenience of drawing preparation.

[0040]FIGS. 1-7 are referred for description. FIG. 1 is a perspective view of a buckle 1. FIG. 2 is an exploded perspective view of the buckle 1. FIG. 3 is an exploded perspective view of the buckle 1 viewed from a different viewpoint from that of FIG. 2. FIG. 4 is an exploded perspective view of the buckle 1, showing one transitional state while the male and female parts M, F are being coupled. FIG. 5 is a top view of the buckle 1 in a state where male and female parts M, F are separated. FIG. 6 is a side view of the buckle 1 in a state where male and female parts M, F are separated. FIG. 7 is a side view of the buckle 1 in a state where male and female parts M, F are coupled. FIGS. 1-7 are illustrated in accordance with a precision based on a product blueprint, and are not just a schematic view.

[0041]In the present specification, directions presented by first and second coordinates C1,C2 respectively associated with female and male parts F,M as shown in FIG. 2 will be referred for descriptions. The first and second coordinates C1,C2 are different in that the front-back directions are inverted and the left-right directions are inverted. The up-down directions in the first and the second coordinates C1,C2 are in parallel and can be deemed as a same direction. The width directions of the female and male parts F,M match the left-right directions of the first and the second coordinates C1,C2, respectively. The thickness directions of the female and male parts F,M match the up-down directions of the first and second coordinates C1,C2, respectively. The length directions of the female and male parts F,M match the front-rear directions of the first and second coordinates C1,C2, respectively.

[0042]The buckle 1 is configured from a female part F and a male part M. The female part F and the male part M each is a plastic part produced through injection molding of plastic material, and has a rectangular shape when viewed from above with a width in the left-right direction greater than a length in the front-rear direction and with a sufficient stiffness (mechanical strength) in enduring collision or friction with other objects. The female and male parts F and M may be produced through 3D-modeling such as by using 3D printer or the like but in such a case, a reinforcement member may preferably be embedded therein to enhance its mechanical strength.

[0043]Exemplarily, the female part F is shaped symmetrically in the up-down direction and in the left-right direction, thereby allowing the use thereof without requiring awareness on the directionality regarding these directions, i.e. allowing the use of female part F in inverted manner in these directions. The male part M according to the illustrated example is shaped symmetrically in the left-right direction but is shaped asymmetrically in the up-down direction (this would be clearer in the following descriptions). Nevertheless, the male part M may be used in inverted manner in the up-down direction.

[0044]The female part F is a part having a female portion 10 in which a female channel 20 and an aperture 30 are formed, the female channel 20 having channel ends 21,22 on both sides in the width direction of the female part F, and the aperture 30 opening the female channel 20 forwardly of the female part F. The female channel 20 penetrates the female portion 10 across the entire width of the female portion 10. The female channel 20 is open on the both left and right sides at the left and right channel ends 21,22, and is open forwardly by the aperture 30, i.e. is open in 3 directions (left, right and front sides). Also, as would be appreciated from the following descriptions, the female channel 20 is open upward, downward and/or rearward at a position between the left and right ends in the entire width of the female portion 10 (e.g. at a middle position between the left and right ends) by an access-window 9 (or a first opening OP1) described hereinafter. The aperture 30 is formed to run in parallel to the female channel 20 in the entire length of the female channel 20 along the width direction of the female part F, and is in spatial communication with the female channel 20 in the entire length of the female channel 20 in the width direction of the female part F. The female part F may further be provided with a bar 41 coupled to the female portion 10 from the rear side, thereby defining a passage for belt 49.

[0045]The male part M includes a male portion 60 which is inserted and retained in the female channel 20 of the female portion 10, and a main body 70 which is interconnected to the male portion 60 rearwardly of the male part M. The main body 70 may have at least one passage 79 for belt (e.g. rearwardly of the main body 70). Exemplarily, a same belt or separate belts may be attached to the female and male parts F and M but, a belt may be embedded therein at the time of injection molding. That is, it is possible to employ any method for fixing a belt to the female and male parts F and M.

[0046]Firstly, the female part F will be focused in more detail. The female portion 10 has a one-side-open or C-like or U-like cross sectional shape, and includes a lower plate 11, an upper plate 12 and an interconnection plate 13 via which the lower plate 11 and the upper plate 12 are interconnected. The lower plate 11 and the upper plate 12 each is a flat or curved plate which is elongated in the width direction of the female part F and is shorter in the length direction of the female part F. The interconnection plate 13 is a flat or curved plate which is elongated in the width direction of the female part F and is narrower in the thickness direction of the female part F. In some cases, the interconnection plate 13 is divided into left and right sections in the width direction of the female part F by the access-window 9 or the opening OP1 noted hereinafter but should not necessarily be limited to this, and the interconnection plate 13 may be formed continuously across the entire width of the female part F.

[0047]The female portion 10 is shaped to retain the male portion 60 in the female channel 20. Preferably, the lower plate 11 and the upper plate 12 are respectively provided with a lower stopper 11a and an upper stopper 12a so that the male portion 60 is prevented from exiting the female channel 20 (moving forward of the female part F) via the aperture 30. The female channel 20 is defined by the lower plate 11 on the lower side, by the upper plate 12 on the upper side, by the interconnection plate 13 on the rear side, and by the lower and upper stoppers 11a and 12a on the front side.

[0048]The lower stopper 11a and the upper stopper 12a are arranged to face each other in the up-down direction, defining an open width of the aperture 30 in the up-down direction. This open width of the aperture 30 is lesser than (e.g. in a range between 50 to 80 percent of) the height of the female channel 20 between the lower plate 11 and the upper plate 12. Exemplarily, the lower and upper stoppers 11a and 12a are respectively formed at the front edges of the lower and upper plates 11 and 12 across the entire width of the female part F. However, these stoppers may be formed intermittently in the width direction of the female part F. For example, the lower and upper stoppers 11a and 12a each may be divided into three sections in the width direction of the female part F. In such a case, the stopper may have a reduced mechanical strength, but facilitating reduction in the weight of the female part F.

[0049]Embodiments are envisaged where the lower stopper 11a and the upper stopper 12a are situated at different positions in the front-rear direction. The aperture 30 may have a varied width in the up-down direction measured between the lower and upper stoppers 11a and 12a in accordance with the offset distance between the lower and upper stoppers 11a and 12a in the front-rear direction. Note that it is absolutely possible to omit one of the lower and upper stoppers 11a and 12a. Other structures of the female part F will be discussed later.

[0050]With additional reference to FIGS. 8-10, the male part M will be focused in more detail. FIG. 8 is a vertical cross-sectional schematic view of the male part M taken along alternate long and short dash lines X8-X8 in FIG. 5. FIG. 9 is a horizontal cross-sectional schematic view of the male part M taken along alternate long and short dash lines X9-X9 in FIG. 6. FIG. 10 is a front view of the male part M. Each of these figures is illustrated in accordance with a precision based on a product blueprint.

[0051]The male portion 60 is a frame portion that is wider in the width direction of the male part M and is shorter in the length direction of the male part M. In detail, the male portion 60 includes a leaf spring 65 which is elastically bendable and deformable responsive to external operation using a cord, a supporting wall 61 that supports one end of the leaf spring 65, a supporting wall 62 that supports the other end of the leaf spring 65, and stopped portions 63,64 which are to be stopped by the lower stopper 11a and the upper stopper 12a respectively. There is a space between the leaf spring 65 and the stopped portion 63,64, allowing the leaf spring 65 to bend and deform rearward. Moreover, a cord-coupled-portion 68 noted hereinafter is allowed to be placed in this space. Note that, the leaf spring 65 and the stopped portion 63,64 are spaced with a first distance in the front-rear direction. The supporting wall 61 and the supporting wall 62 are spaced with a greater second distance in the left-right direction. The second distance may be in a range of three to eight times the first distance.

[0052]The leaf spring 65 has an external face 65a and an internal face 65b by which a plate thickness of the leaf spring 65 is defined. The external face 65a of the leaf spring 65 is a surface that is slightly curved forward in the entire width between the left and right supporting walls 61,62, and on which no protrusion is arranged except for an engagement protrusion 80 (lower and upper protrusions 81,82) noted hereinafter which protrudes forwardly of the male part M. As such a leaf spring 65 is employed, smoother insertion of the male portion 60 into the female channel 20 is promoted, and simplification of mold for the male part M is facilitated. In an initial posture where the leaf spring 65 is not elastically deformed, the external face 65a is curved out away from the main body 70 at the center in the width direction of the male part M. Similarly, the internal face 65b is curved out away from the main body 70 at the center in the width direction of the male part M.

[0053]Exemplarily, the plate thickness of the leaf spring 65 defined between the external and internal faces 65a and 65b is in a range between 1.0 to 3.0 mm. If the plate thickness was too thinner, there is a possibility that a target coupling strength is not achieved, and its mechanical strength may be reduced. If the plate thickness was too thick, there is a possibility that the coupling strength becomes too large, making it not easier to decouple the male and female parts M and F even when a cord is operated.

[0054]Preferably, the external face 65a has a radius of curvature which is 0.4 meter or more, 0.5 meter or more, or 0.6 meter or more. The internal face 65b may have a radius of curvature which is substantially equal to the radius of curvature of the external face 65a but could be different from it. In a situation where the male part M is injection-molded such that the leaf spring 65 has a greater radius of curvature, it is expected that the cost for a mold and/or the occurrence of molding defects is reduced. The leaf spring 65 may have any size and/or shape as long as being capable of deforming in accordance with external force applied directly or indirectly thereto and elastically recovering to the initial posture as the external force is removed. For example, it is possible to employ a leaf spring which has a smaller width in the up-down direction than that of the illustrated leaf spring. It is possible to employ a leaf spring with a wave-like upper edge and a wave-like lower edge. It is possible to employ a leaf spring having a height in the up-down direction which fluctuates along the width direction of the male part M. It is possible to employ a leaf spring having a plate thickness which fluctuates along the width direction of the male part M.

[0055]The leaf spring 65 has a cord-coupled-portion 68 to which the cord is coupled for a purpose of external operation using the cord, and optionally has displacement-restricting protrusion(s) 69p,69q by which a maximum deformation point for the leaf spring 65 is defined. The cord is pulled rearwardly of the male part M, causing the cord-coupled-portion 68 to be moved rearward and thereby causing the leaf spring 65, to which the cord-coupled-portion 68 is interconnected, to bent or curved in an arc rearward.

[0056]The cord-coupled-portion 68 is arranged to be interconnected to the internal face 65b of the leaf spring 65, not to the external face 65a thereof. That is, the cord-coupled-portion 68 is arranged to protrude into the space inside the frame of the male portion 60, thereby ensuring smoother insertion of the male portion 60 into the female channel 20. Preferably, the cord-coupled-portion 68 has a width in the left-right direction that gradually reduces as being away from the leaf spring 65 rearwardly. As the cord is pulled rearward to bend the leaf spring 65 rearwardly, a rear end of the cord-coupled-portion 68 would be smoothly received by a channel 7 for cord noted hereinafter.

[0057]The displacement-restricting protrusion 69p,69q is arranged to collide with the stopped portion 63,64 (specifically, a wall surface of the male portion 60 defining the space inside the frame of the male portion 60) as the cord-coupled-portion 68 is pulled rearwardly by the cord, thereby suppressing the break of the leaf spring 65. A distance in the front-rear direction between the displacement-restricting protrusion 69p,69q and the wall surface of the stopped portion 63,64 when the leaf spring 65 is not deformed may be set corresponding to a maximum deformation tolerance of the leaf spring 65 or a deformation tolerance lesser than the maximum deformation tolerance. In the illustrated example, the displacement-restricting protrusions 69p,69q are interconnected to the cord-coupled-portion 68 on both left and right sides, thereby enhancing the mechanical strength, not necessarily be limited to this though.

[0058]The cord-coupled-portion 68 may include an internal passage 68a through which the cord passes, a pillar 68b about which the cord is wound, and a cord-retaining portion 68c that presses and retains the cord (particularly, see FIG. 9). Optionally, the internal passage 68a reaches the external face 65a of the leaf spring 65 to form a second opening OP2 (i.e. another opening that is different from the opening OP1) in the external face 65a (particularly, see FIG. 10), and the cord-retaining portion 68c and the pillar 68b are arranged in this order in a direction away from the opening OP2 of the leaf spring 65. In such case, the cord is loosely would about the pillar 68b and then pulled rearward so that the cord is automatically inserted into and held by the cord-retaining portion 68c, allowing easier attachment of the cord. Note that the female portion 10 does not have a protrusion that protrudes into the opening OP2, thus facilitating simplification of mold for the female part F.

[0059]The cord-retaining portion 68c is configured to reduce the width of the internal passage 68a, preferably configured to reduce the width thereof in the thickness direction of the male part M (e.g. see FIG. 8). In some cases, the cord-retaining portion 68c includes an upper portion positioned above the internal passage 68a and a lower portion positioned under the internal passage 68a. A distance in the up-down direction between these upper and lower portions is less than a diameter of the cord (or less than a maximum width of the cord). Exemplarily, the cord has a circular or oval cross-sectional shape. The cord may be a knitted or braided cord that is stretchable in its longitudinal direction and has shape-recoverable feature in its cross-sectional direction, but should not be limited to this and any cords such as a paper cord, a hemp cord or a metal cord (e.g. electrical wire cord) are usable. That is, it is sufficient for the cord to be used to operate the leaf spring 65, and there is no limitation on its material.

[0060]The stopped portion 63,64 has a lower end downwardly protruding from the lower surface of the main body 70. If the male part M is moved away from the female part F in a state where the female and male parts F, M are coupled, the lower end of the stopped portion 63,64 collides with the lower stopper 11a and is prevented from moving. Similarly, the stopped portion 63,64 has an upper end upwardly protruding from the upper surface of the main body 70. If the male part M is moved away from the female part F in a state where the female and male parts F, M are coupled, the upper end of the stopped portion 63,64 collides with the upper stopper 12a and is prevented from moving. Ideally, the above-noted two timings of collisions are the same.

[0061]When the male and female parts M, F are coupled, the cord-coupled-portion 68 is arranged in the female channel 20 of the female portion 10. Therefore, it is preferable to provide a channel for cord on either one of the male part M or the female part F for allowing the cord, attached to the cord-coupled-portion 68, to run into the outside. It is preferred to apply a linearly, rearwardly pulling force to the leaf spring 65 so as to bend the leaf spring 65 rearward. This is particularly true for cases where the leaf spring 65 has a thickness that does not allow easier bending thereof (e.g. thickness equal to or greater than 5 mm or 8 mm). In view of the above-noted points, it is preferable to provide the channel 7 for cord at the male part M. However, it should not be limited to this and for example, the channel for cord may be formed by forming an opening or cutout at the female portion 10 of the female part F. As an example, it is possible to extend the opening OP1 noted hereinafter to reach the front end of the female portion 10, thereby forming the channel for cord.

[0062]The main body 70 has a channel 7 for cord through which the cord is allowed to extend rearwardly away from the cord-coupled-portion 68. The channel 7 for cord is in spatial communication to the space inside the frame of the male portion 60. Exemplarily, the channel 7 for cord is in spatial communication to the passage 79 for belt. In the illustrated example, the channel 7 for cord is partially open in the up-down direction and has a width in the left-right direction which is sufficiently greater than the diameter or the width of the cord, thereby allowing easier insertion of the cord into the channel 7 for cord and allowing visual recognition of the inserted state of the cord therein.

[0063]The main body 70 may have one or more lower bars 71 and one or more upper bars 72 which sandwich the cord on both upper and lower sides. The cord, which has been inserted through the channel 7 for cord, is sandwiched between the upper bar 71 and the lower bar 71, thereby the cord is positioned at or closer to the center in the thickness of the male part M, facilitating stable rearward pulling of the cord for a purpose of rearwardly bending and deforming the leaf spring 65.

[0064]The main body 70 has left and right plate-like portions 78p,78q which are arranged on both left and right sides of the channel 7 for cord and by which a width of the channel 7 for cord in the left-right direction is defined, and a rear rod 78r which defines the passage 79 for belt from the rear side (i.e. arranged rearwardly of the passage 79 for belt). The rear rod 78r is interconnected to the left and right ends of the left and right plate-like portions 78p,78q, thereby defining the passage 79 for belt.

[0065]The plate-like portions 78p,78q extend toward the center in the width direction of the female part F from an outer peripheral portion of the main body 70, thereby defining the channel 7 for cord. The channel 7 for cord has a channel width that is defined by opposed surfaces of the plate-like portions 78p,78q. Preferably, the channel 7 for cord is shaped such that the channel width in the left-right direction gradually increases forwardly of the male part M, thereby avoiding interference with the cord-coupled-portion 68. The upper bar 72 extends across the left and right plate-like portions 78p,78q in the width direction of the male part M, and the lower bar 71 extends similarly.

[0066]Preferably, the left and right plate-like portions 78p,78q each has a thickness that is lesser than a distance in the up-down direction between the lower and upper stoppers 11a and 12a, thereby facilitating smoother insertion of the male portion 60 into the female channel 20. The main body 70 may be provided with a circumferential wall 75 on its one or both of the upper and lower surfaces and in this case, grooves 76 may be formed adjacent to the stopped portion 63,64 so as to avoid interference with the lower stopper 11a or the upper stopper 12a. The front surface of the rear rod 78r is a sloped surface 78s that is slanted across substantially entire thickness of the rear rod 78r (see FIG. 8), thereby avoiding or suppressing interference with the cord and the belt in the passage 79 for belt. The substantially entire thickness stated here indicates a thickness that is equal to or greater than 80% of a thickness measured between the upper and lower surfaces of the rear rod 78r which are joined via the front surface of the rear rod 78r.

[0067]Next, we focus on displacement restriction for the male portion 60 inside the female channel 20 in the width direction of the buckle 1. For a purpose of displacement restriction for the male portion 60 inside the female channel 20, the leaf spring 65 is provided with an engagement protrusion 80, and a protrusion-accommodating portion 85 is formed in the female portion 10.

[0068]The engagement protrusion 80 includes a lower protrusion 81 and an upper protrusion 82 which are opposed to each other with an interspace in the up-down direction, and both the lower protrusion 81 and the upper protrusion 82 may be accommodated in the protrusion-accommodating portion 85 (the opening OP1 noted hereinafter). This would reduce an influence imparted to the elastic characteristic of the leaf spring 65, compared with an embodiment where a single large protrusion is provided. The lower protrusion 81 and the upper protrusion 82 have opposed surfaces, each of which is a flat surface thereby avoiding complicated structure of mold core for the internal structure of the cord-coupled-portion 68 (e.g. the internal passage 68a, the pillar 68b, and the cord-retaining portion 68c).

[0069]The lower protrusion 81 includes a slanting region in its lower surface which slants upward as extending toward the front end of the lower protrusion 81, and thus the lower protrusion 81 is formed thinner toward its front end. The upper protrusion 82 includes a slanting region in its upper surface which slants downward as extending toward the front end of the upper protrusion 82, and thus the upper protrusion 82 is formed thinner toward its front end.

[0070]The protrusion-accommodating portion 85 is a space recessed rearwardly of the female part F so as to accommodate the engagement protrusion 80 protruding forwardly of the male part M. In some cases, the protrusion-accommodating portion 85 penetrates the interconnection plate 13 or is formed as a recess on the inner surface of the interconnection plate 13. The former case facilitates easier molding of the protrusion-accommodating portion 85. Moreover, in the former case, the engagement protrusion 80 is preferably accommodated in the protrusion-accommodating portion 85 without protruding rearward than the rear surface of interconnection plate 13. This avoids or suppresses that an external object is caught by the engagement protrusion 80 protruding rearward than the rear surface of the interconnection plate 13.

[0071]The engagement protrusion 80 and the protrusion-accommodating portion 85 are engaged through elastic deformation of the leaf spring 65, thereby preventing the male portion 60 from moving inside and along the female channel 20; and the engagement protrusion 80 is releasable from the protrusion-accommodating portion 85 as the leaf spring 65 bends and deforms responsive to the external operation using the cord. In particular, in a state where the male portion 60 is inserted into the female channel 20 and where the engagement protrusion 80 and the protrusion-accommodating portion 85 are engaged with each other, it is difficult or practically hard to externally access the leaf spring 65 except for the external operation using the cord provided in advance. This makes it possible to permanently or semi-permanently maintain the condition in which the male portion 60 is prevented from moving inside and along the female channel 20, except for the external releasing operation using the cord provided in advance. On the other side, if some factors made it difficult to externally operate the leaf spring 65 by using the cord, there is a possibility that a user encounters a difficult situation where it is hard to decouple the female part F and the male part M.

[0072]In the present embodiment, the female portion 10 has at least one access-window 9 through which external force is applicable directly or indirectly to the leaf spring 65 for releasing the engagement protrusion 80 from the protrusion-accommodating portion 85 in a state where the engagement protrusion 80 and the protrusion-accommodating portion 85 are engaged to prevent the male portion 60 from moving inside and along the female channel 20; thereby temporal releasing is enabled by the access-window 9. By way of precaution, the access-window 9 is an opening which is different from the channel end 21,22. In some cases, the access-window 9 (and/or the opening OP1 noted hereinafter) penetrates each of the lower plate 11, the upper plate 12 and the interconnection plate 13, enabling accesses in plural directions.

[0073]Again, if difficulty arises in externally operating the leaf spring 65 by using the cord provided in advance, this would cause difficulty in decoupling for the buckle 1. For example, in an instance where the buckle 1 is used to fix a defense equipment in a ship or in an airplane, the use of such defense equipment may be hindered. The above-noted access-window 9 provides a temporal remedy to such an instance. For example, a rod-like member (e.g. narrow rod-like tool (cross slot screwdriver, straight slot screwdriver)) is inserted into the access-window 9 to forcibly bend the leaf spring 65 by the rod-like member so that the engagement protrusion 80 and the protrusion-accommodating portion 85 are disengaged, allowing a user to laterally puling the male portion 60 to escape from the female channel 20. Note that the direction of the lateral pulling matches the width direction of the buckle 1.

[0074]Manner or extent of the engagement between the engagement protrusion 80 and the protrusion-accommodating portion 85 would be determined based on individual needs. In one case, the engagement protrusion 80 and the protrusion-accommodating portion 85 are engaged in loose fit (clearance fit), and the engagement protrusion 80 is (typically, slightly) displaceable inside the protrusion-accommodating portion 85 in the width direction of the buckle 1 (e.g. the distance of the displacement may be about 6 mm at the maximum). In another case, the engagement protrusion 80 is pressed into and fitted with (e.g. press-fitted to) the protrusion-accommodating portion 85 (by the spring force of the leaf spring 65). In either case, it is possible to restrict the displacement of the male portion 60 inside and along the female channel 20.

[0075]Fundamentally, the protrusion-accommodating portion 85 does not need to penetrate the female portion 10 (e.g. the interconnection plate 13), and it is just sufficient to be recessed in a direction (e.g. in the rear direction of the female part F) crossing the elongated direction of the female channel 20. In contrast, unlike the protrusion-accommodating portion 85, the access-window 9 needs to penetrate the female portion 10 (one of or selected two of or every of the lower plate 11, the upper plate 12 and the interconnection plate 13), otherwise external access to the leaf spring 65 situated inside the female channel 20 would be not possible. Note that an embodiment is envisaged where a slidable lid is mounted to close the access-window 9 and, when necessary, is slid to open the access-window 9. It is also optional to cover the access-window 9 with a removable or destroyable film (e.g. transparent or color film, rubber sheet or seal) and when necessity of use arises, it is removed or destroyed to reveal the access-window 9.

[0076]As described above, there are different requirements for the protrusion-accommodating portion 85 and the access-window 9 and accordingly, their locations and sizes would be determined individually. Therefore, in this context, the protrusion-accommodating portion 85 and the access-window 9 may be situated at different locations. However, from one or more viewpoints such as simplification of mold structure (in turn, simplification of the structure of the female part F), the stiffness or mechanical strength of the female part F, and the operability for decoupling via the access-window 9, the optimal approach may be situating the protrusion-accommodating portion 85 and the access-window 9 at the same location in the width direction of the female portion 10 thereby forming a first opening OP1 that serves as both the protrusion-accommodating portion 85 and the access-window 9.

[0077]The opening OP1 is formed to penetrate the female portion 10 from the external surface of the female portion 10 to the female channel 20, allowing external force to be applied indirectly to the leaf spring 65 via the engagement protrusion 80 situated in the opening OP1 in the engaged state of the engagement protrusion 80 and the protrusion-accommodating portion 85. Enhanced operability is ensured by indirectly pushing the leaf spring 65 via the engagement protrusion 8, not by directly pushing the leaf spring 65. Note that, it could be said that the protrusion-accommodating portion 85 and the access-window 9 are provided by the common opening OP1 which is formed to penetrate the female portion 10 from the external surface of the female portion 10 to the female channel 20.

[0078]The engagement protrusion 80 (preferably, both the lower protrusion 81 and the upper protrusion 82) is situated in the opening OP1 without protruding from the opening OP1. That is, the engagement protrusion 80 does not protrude externally (e.g. toward the rear side, toward the upper side, or toward the lower side) relative to the external surface (e.g. the rear surface, the upper surface or the lower surface) of the female portion 10 while being situated in the opening OP1, and thus suppressing the decoupling of the female part F and the male part M at an unintended timing. However, the floating condition of the engagement protrusion 80 in the opening OP1 is externally visible and perceivable, and this may be sufficient in allowing a user, who is not educated in advance on how the access-window 9 is used, to notice the operation extemporaneously (as long as the access-window 9 is not sealed) which includes pushing the engagement protrusion 80 via the access-window 9, elastically deforming the leaf spring 65, and allowing the engagement protrusion 80 to escape from the protrusion-accommodating portion 85.

[0079]The access-window 9 and/or the opening OP1 is defined between left and right wall surfaces 85a,85b which are opposed to each other with an interspace in the width direction of the female portion 10, and the interspace between the left and right wall surfaces 85a,85b is 1 cm or less, preferably in a range between 3 mm to 10 mm, thereby avoiding or suppressing that the access space is enlarged too much unnecessarily to cause unintentional disengagement of the engagement protrusion 80 and the protrusion-accommodating portion 85. The left and right wall surfaces 85a,85b are stopping surfaces of the protrusion-accommodating portion 85 by which the engagement protrusion 80 is prevented from moving.

[0080]Here, distinctive structures of the female portion 10 will be discussed. The interconnection plate 13 is provided with at least one guide protrusion 3 that guides the male portion 60 moving along the female channel 20. The guide protrusion 3 has a rectangular cross-sectional shape, thereby spatially downsizing the channel end 21,22 of the female channel 20 and facilitating stabler insertion of the male portion 60 into the female channel 20 (simultaneously, making it difficult to access the leaf spring 65 from the channel end 21,22). Exemplarily, one guide protrusion 3 is positioned at an intermediate (middle) height between the lower plate 11 and the upper plate 12. The guide protrusion 3 and the lower plate 11 are arranged to form a lower groove 4p therebetween into which the lower protrusion 81 is inserted, and the guide protrusion 3 and the upper plate 12 are arranged to form an upper groove 4q therebetween into which the upper protrusion 82 is inserted. The guide protrusion 3 is not necessarily formed across the entire length of the female channel 20. In the illustrated example, the access-window 9 or the opening OP1 is formed to penetrate the interconnection plate 13 and, at this penetration location the guide protrusion 3 is not formed. As a result, the guide protrusion 3 is divided into left and right sections arranged on both sides of the access-window 9 or the opening OP1. As the number of the access-window 9 increases, the number of the guide protrusion 3 may increase (e.g. the guide protrusion 3 may be divided into three discontinuous sections).

[0081]The interconnection plate 13 has at least one sloped surface 5p,5q on which the engagement protrusion 80 slides to bend the leaf spring 65 as the male portion 60 is inserted into the female channel 20. Exemplarily, left and right sloped surfaces 5p,5q are arranged on both sides of the opening OP1. The left and right sloped surfaces 5p,5q form a convex (i.e. forwardly protruding) tapered shape which protrudes into the female channel 20. Owing to the sloped surfaces 5p,5q, it is promoted to mold the leaf spring 65 with a greater radius of curvature (such as injection molding or the like). In a case where the leaf spring 65 is molded to have a greater radius of curvature, the female part F and the male part M may be coupled by smaller force.

[0082]In a case where the lower groove 4p and the upper groove 4q are formed, the left and right sloped surfaces 5p,5q may be bottom surfaces of the lower groove 4p and the upper groove 4q. One of the left and right sloped surfaces 5p,5q may be optionally omitted for a purpose of limiting the insertion and separation (exit) directions of the male portion 60 into and from the female channel 20 to one side of the left and right sides. Immediately understandable from the drawings is that the height of the guide protrusion 3 decreases as the height of the sloped surface increases.

[0083]FIGS. 11-13 will be referred to discuss a process in which the female and male

[0084]Parts F, M are coupled. Firstly, the male portion 60 is inserted into the female channel 20 (see FIG. 11). In detail, the male portion 60 is inserted into the female channel 20 from one channel end (e.g. the channel end 21) toward the other channel end (e.g. the channel end 22), and is held in the female channel 20. In this state, the lower plate 11 on the lower side, the upper plate 12 on the upper side, the interconnection plate 13 on the rear side, and the lower stopper 11a and the upper stopper 12a on the front side restrict the position of the male portion 60. Next, the male portion 60 is slid inside and along the female channel 20, and the engagement protrusion 80 (e.g. the lower protrusion 81 and the upper protrusion 82) collides with the sloped surface 5p (see FIG. 12).

[0085]Force is applied to the male part M to further slide the male portion 60, and the leaf spring 65 is bent rearward of the male part M (e.g. in a shallow arc or shallow V-shape), and the engagement protrusion 80 moves in the same direction (see an arrow in FIG. 12). In some embodiments, when the leaf spring 65 is bent rearward, the supporting walls 61,62 may deform toward the center in the width direction of the male part M. After the engagement protrusion 80 has moved across the sloped surface 5p, the leaf spring 65 elastically recovers to or closer to its original posture, i.e. the leaf spring 65 moves forwardly of the male part M and the engagement protrusion 80 is displaced in the same direction. This results in that the engagement protrusion 80 enters into and engages with the protrusion-accommodating portion 85, thus preventing the male portion 60 from sliding along the female channel 20 (see FIG. 13). The engagement protrusion 80 may be slightly displaceable between the left and right wall surfaces 85a,85b or be lightly press-fitted into between the left and right wall surfaces 85a,85b.

[0086]When the female part F and the male part M have been fully coupled, the leaf spring 65 is situated inside the female channel 20. Thus, it is not possible to see it externally in the top view, the bottom view and the rear view of the female part F (except for viewing through the access-window 9 or the opening OP1). Exemplarily, when the female part F and the male part M have been fully coupled, it is not possible to see or hardly see from the outside the leaf spring 65 in the left-side view, the right-side view, and front-side view of the female part F. When the female part F and the male part M have been fully coupled, the channel end 22 may be closed by the supporting wall 61, and similarly the channel end 21 may be closed by the supporting wall 62.

[0087]Referring to FIGS. 14-16, operations for decoupling the female part F and the male part M will be discussed. Firstly, the protrusion-accommodating portion 85 and the engagement protrusion 80 are in the engaged state, the male portion 60 is prevented from sliding along the female channel 20 (see FIG. 14). As the cord is pulled rearwardly of the male part M, the cord-coupled-portion 68 is displaced in the same direction and accordingly, the leaf spring 65 bends in the same direction (see FIG. 15). As the engagement protrusion 80 is displaced (rearwardly of the male part M) over a sufficient distance for escaping from the protrusion-accommodating portion 85 (see FIG. 16), the male portion 60 is brought into a slidable condition along the female channel 20. The cord may be linearly pulled rearward of the male part M, followed by the cord being pulled rearward and obliquely rightward or leftward of the male part M, thereby allowing the engagement protrusion 80 to escape from the protrusion-accommodating portion 85 and successively allowing the male portion 60 to slide along the female channel 20. Note that the left corner and/or right corner of the distal end of the engagement protrusion 80 may be chamfered, allowing smoother conversion from the rearward movement into the leftward or rightward movement of the engagement protrusion 80. If the engagement protrusion 80 is loosely accommodated in the protrusion-accommodating portion 85, this ensures smoother conversion from the rearward movement into the leftward or rightward movement thereof (the engagement protrusion 80 is movable leftward or rightward in the protrusion-accommodating portion 85, allowing the leftward or rightward movement to initiate against a lower frictional resistance).

[0088]As discussed above, the access-window 9 (the opening OP1 serving also as the access-window 9) is provided to enable temporal decoupling of the male and female parts M, F. This feature is as illustrated in FIG. 17. With reference to FIG. 17 seen in front of a viewer, a bar-like member (not illustrated) can easily access the lower protrusion 81 from the lower and left oblique side and similarly, can easily access the upper protrusion 82 from the upper and left oblique side. As the female channel 20 of the female portion 10 is open by the opening OP1 in three directions of the upper side, the lower side and the rear side, the lower protrusion 81 and the upper protrusion 82 can be operated simultaneously or together by using a common bar-like member. The bar-like member pushes the lower protrusion 81 and/or the upper protrusion 82 to exit the opening OP1 and to enter the female channel 20. As such, the lower and upper protrusions 81,82 are disengaged from the protrusion-accommodating portion 85, allowing the male portion 60 to escape from the female channel 20 through the lateral pulling. Again, there is no need to situate the access-window 9 at the same location as the protrusion-accommodating portion 85. Two access-windows 9 may be formed to sandwich and on both sides of the protrusion-accommodating portion 85 in the width direction of the female part F.

[0089]Another embodiment according to the present disclosure will be discussed with reference to FIGS. 18 and 19. In this another embodiment, the protrusion-accommodating portion 85 is formed in the leaf spring 65, and the female portion 10 is provided with the engagement protrusion 80. The engagement protrusion 80 is configured to protrude forwardly of the female part F into the female channel 20. Furthermore, the access-window 9 is situated at another location from the protrusion-accommodating portion 85. Also in such embodiment, similar effects as noted above would be obtained to an extent without causing any contradictions. The above-noted features alone or in combination can be applicable in an extent without causing any contradictions.

[0090]As schematically shown in FIG. 18, the female portion 10 has the engagement protrusion 80 protruding into the female channel 20. The leaf spring 65 is formed to have a radius of curvature which is lesser than that of the above-noted embodiment. The protrusion-accommodating portion 85, with which the engagement protrusion 80 is engaged, is formed at a summit of the leaf spring 65 which is curved to protrude forwardly of the male part M. The leaf spring 65 is provided with the cord-coupled-portion 68 (not depicted), and the engagement protrusion 80 and the protrusion-accommodating portion 85 can be disengaged. Unlike the above-described embodiment, the access-window 9 is situated at a different location from the protrusion-accommodating portion 85. In particular, two access-windows 9 are situated on both left and right sides of the engagement protrusion 80. Furthermore, it is possible to directly operate the leaf spring 65 via the access-window(s) 9. Even in such embodiment, the access-window 9 enables temporal releasing.

[0091]Based on the above disclosure, a skilled person in the art would be able to add various modifications to the respective features and respective embodiments. Reference codes in Claims are just for reference and should not be referred for the purpose of narrowly construing the scope of claims.

REFERENCE CODE