JP7556578B2 - Fastening structure - Google Patents

Description

The present invention relates to a fastening structure, and in particular to a fastening structure used when assembling returnable boxes using sheet materials such as plastic corrugated cardboard.

To transport products between factories, returnable boxes made of plate materials are used. For example, in the returnable box disclosed in Patent Document 1, plastic cardboard is folded to form a rectangular box with an opening on one of the six sides facing upward. To create such returnable boxes, plate materials such as plastic cardboard, thick paper, plate-shaped cushioning material, and plywood are fastened and bound as appropriate.

In general work of overlapping the faces of plate materials and fastening them with bolts and nuts, the bolt side and the nut side are each fitted with a tool such as a wrench, so work must be done on both the main surface and the back surface of the fastened members. For example, if the fastening point of the bolt and nut is located at the back of a box, there is a problem that it is difficult to reach the inside or to insert a tool. Patent Document 2 discloses a fastening mechanism that can tighten and fasten the fastened members from one direction with bolts and nuts, improving the workability of fastening. Patent Document 3 discloses a mounting tool that can be joined and fixed with one touch by driving in a screw, rather than fastening with bolts and nuts.

JP 2001-354228 A JP 2016-8647 A Japanese Unexamined Patent Publication No. 2-279850

According to the techniques of Patent Documents 2 and 3, plates can be fastened together from one direction, but the bolt shaft of the fastening mechanism or the insertion tip of the attachment protrudes from the front and back surfaces of the plates. However, such protrusions on the inside of the box body are undesirable when used as returnable boxes. In addition, due to the nature of returnable boxes, it is also desirable for them to be easily disassembled so that they can be dismantled and separated for disposal at the delivery destination.
The present invention has been made to solve the problems described above, and aims to provide a fastening structure that can fasten plate materials together from one direction, reduces protrusion from the front and back surfaces of the plates, and can be disassembled.

The fastening structure of the present invention comprises a main box having a bottom surface portion passing through a composite hole formed by overlapping a circular hole and a rectangular hole whose short side is shorter than the diameter of the circular hole and whose long side is longer than the diameter of the circular hole with their centers aligned, a side surface portion rising up around the entire periphery of the bottom surface portion, a visor portion protruding outwardly parallel to the bottom surface portion from the upper edge of the side surface portion around the entire periphery, and a pair of shaft insertion portions rising up from the bottom surface portion on either side of the circular hole;
a flange portion large enough to cover almost the entire bottom surface portion, a shaft portion rising from the center of the flange portion and having a diameter equal to the diameter of the circular hole, and a knob portion of a rectangular parallelepiped shape provided on the top of the shaft portion and having a planar shape that can pass through the rectangular hole, the knob portion being inserted into the composite hole from the top to the shaft portion with the flange portion remaining overlapped within the range of the shape of the bottom surface portion on the back side of the bottom surface portion, and the knob portion being positioned above the upper edges of the pair of shaft insertion portions;
a plurality of plate materials to be bound, each of which has an insertion hole formed therein, the insertion hole having a shape that allows the plate materials to pass when the orientation of the bottom surface portion is at a first angle and does not allow the plate materials to pass when the orientation of the bottom surface portion is not at the first angle;
The flange and bottom portion are inserted into one side of a plurality of plate materials with the insertion holes aligned and overlapped, and by rotating the knob portion from a first angle to a second angle, the overlap between the flange and bottom portion is released and the plurality of plate materials are sandwiched between the flange and eaves portion.

The fastening structure of this invention allows plates to be fastened together from one direction, minimizing protrusions from the front and back of the plates, and allows the plates to be easily disassembled and disposed of separately after use.

1A is a perspective view of the top and bottom of a main box, FIG. 1B is a perspective view of the top and bottom of a rotating knob, and FIG. 1C shows how plate materials are fastened together. 2A and 2B are perspective views of a fastener before binding plate materials, and FIGS. 2C and 2D show the fastener after binding plate materials. 3A is a diagram showing a pair of shaft insertion portions and a knob portion, where FIG. 3A is a partially enlarged view of the knob portion, FIG. 3B is a plan view of the pair of shaft insertion portions, and FIGS. 3C to 3E are cross-sectional views of the shaft portion when the fastener is changed from an unlocked state to a locked state. 4A is a diagram showing the process of connecting the main box and the rotating knob, FIG. 4B is a diagram showing the positional relationship between the shaft insertion portion and the knob portion when locked, FIG. 4C is an X-X cross-sectional view, and FIG. 4D is a Y-Y cross-sectional view. 5A is a diagram showing the function of the fastener before it is inserted into the insertion hole of the plate material, FIG. 5B is a diagram after it has been inserted, and FIG. 5C is a diagram after it has been bound.

The fastening structure of the embodiment of the present invention is shown in FIG. 1. The fastener 1 according to the fastening structure of the embodiment of the present invention is composed of two parts, a main box 20 and a rotating knob 40, and by connecting these two parts, the fastener 1 with a rotating mechanism is formed. The fastener 1 is a resin fastener that can be used to bind and fix plate materials as a substitute for double-sided tape or rivets, and can be operated from one side of the plate materials w1, w1. The plate materials w1, w1 according to the fastening structure of the embodiment of the present invention may be plastic cardboard, thick paper, plywood, etc., or may be cushioning materials such as rubber or foam material. Note that the fastener 1 described below is assumed to have a total thickness of 10 mm on the plate material sides to be joined, but the present invention is not limited to this, and of course various thicknesses may be set. In the figure, x, y, and z indicate a three-dimensional orthogonal coordinate system.

[Overall explanation]
First, in FIG. 1A, the main box 20 has a rectangular bottom surface 21 in a plan view (x-y plane), a side surface 22 rising in the z direction around the entire circumference of the bottom surface 21, and a eaves portion 23 protruding outward in parallel with the bottom surface 21 from the upper edge of the side surface 22 around the entire circumference. The distance d1 (z direction in the figure) from the lower surface of the bottom surface 21 to the lower surface of the eaves portion 23 is 10 mm. A circular hole 24 (partially drawn by a broken line) penetrates the center of the bottom surface 21, and a pair of shaft insertion portions 26, 26 rise in the z direction on either side of the circular hole 24. In addition, a rectangular hole 25 (also partially drawn by a broken line) penetrates the bottom surface 21. The circular hole 24 and the rectangular hole 25 overlap each other with their centers aligned to form a composite hole 30. Of these, the rectangular hole 25 has a short side (y direction in the figure) shorter than the diameter of the circular hole 24, a long side (x direction in the figure) longer than the diameter, and the centers of the circular hole 24 and the rectangular hole 25 are aligned. The direction of the long side of the rectangular hole 25 is aligned with the direction of the long side of the bottom surface portion 21. The edge of the circular hole 24 is removed by the rectangular hole 25 to form two arc-shaped walls 27. Each of these arc-shaped walls 27 is directly the inner wall of a pair of shaft insertion portions 26, 26. Each shaft insertion portion 26, 26 is lower than the side surface portion 22 in the z direction. In addition, the inside of the upper edge side of each shaft insertion portion 26, 26 has an inner curved wall 28 that further expands toward both ends of the arc. A groove 32 is provided in the z direction at the center of the inner curved wall 28 on the upper edge 29 side of each shaft insertion portion 26, 26. The upper edge 29 of each shaft insertion portion has a high central portion 29a and an inclined surface 29b that descends toward both ends. The central portion 29a is flat, and both sides of the central portion 29a are surrounded by protrusions 29c that are slightly higher than the central portion. The width (x direction) of the central portion 29a is equal to the length of the short side of the rectangular hole 25.

On the other hand, in FIG. 1B, the rotating knob 40 has a flange portion 41, a shaft portion 42, and a knob portion 43. The flange portion 41 is large enough to cover almost the entire bottom surface portion 21 in the x-y plane, and has a shape in plan view surrounded by a pair of straight sides 41a, 41a that overlap the long sides of the bottom surface portion 21, and a pair of arc sides 41b, 41b that connect both ends of the pair of straight sides 41a, 41a. First tapered surfaces 41d, 41d are provided that rise inward along the pair of straight sides 41a, 41a so as to increase the thickness (z direction) of the flange portion 41. At the center of the flange portion 41, a shaft portion 42 with a diameter equal to the diameter of the circular hole 24 rises in the z direction. The knob portion 43 is provided on the top of the shaft portion 42, and is a rectangular parallelepiped having a rectangular shape in plan view that can pass through the rectangular hole 25. The direction of the straight sides 41a, 41a of the knob portion 43 is the same as the direction of the long side of the rectangular shape of the knob portion 43 in a plan view. It is desirable that the distance d2 from the rising edge of the shaft portion 42 to the top surface of the knob portion 43 is within the range of the distance d3 from the lower surface of the bottom surface portion 21 to the outside of the eaves portion 23. Specifically, it is set to 10 mm + 2 mm (2 mm is the thickness of the eaves portion 23), but is not limited to this. By incorporating the arc sides 41b, 41b into the shape of the flange portion 41, it is possible to prevent rotation or damage to the flange portion 41 due to unintended external forces. In addition, when arranging a member that surrounds the flange portion 41, the bittern shape can be minimized, making it possible to apply it to narrow spaces.

In FIG. 1C, a common insertion hole 50 is provided on the side of the plate materials w1, w1 to be joined. The insertion hole 50 is the same rectangular shape as the bottom surface portion 21, and the bottom surface portion 21 can be inserted into the insertion hole 50 at a predetermined first angle at which the orientations of the two match. In the figure, two plate materials w1, w1 are shown, but the number of plates w1, w1 may be two or more as long as the total thickness of the plate materials w1, w1 to be joined is 10 mm. The plate materials w1, w1 are stacked with the insertion holes 50 aligned. The fastener 1 is inserted into the insertion hole 50 from one side of the plate materials w1, w1 at a predetermined first angle that matches the orientation of the shape of the insertion hole 50 and the orientation of the shape of the bottom surface portion 21. Then, the knob portion 43 is turned to bind the plate materials.

In Fig. 2, a perspective view of the fastener 1 is shown, with Figs. 2A and 2B showing the state before the plate materials w1, w1 are fastened, and Figs. 2C and 2D showing the state after the plate materials w1, w1 are fastened (plate materials w1, w1 are omitted in Figs. 2C and 2D). Before fastening, the rotating knob 40 overlaps the rectangular hole 25 in a plan view, with the knob portion 43 positioned between the pair of shaft insertion portions 26, 26. The knob portion 43 passes through the composite hole 30 in the bottom portion 21, and is in a position before the knob portion 43 ascends the inclined surface 29b. The flange portion 41 overlaps the bottom portion 21.

When the knob portion 43 is rotated a predetermined second angle (90°), since the main box 20 is surrounded by the insertion holes 50 of the plate materials w1, w1, the main box 20 does not rotate, and only the rotating knob 40 rotates. The knob portion 43 ascends the inclined surface 29b, overcomes the protruding strip 29c, and fits within the range of the central portion 29a, becoming a "locked" form. The state at this point is shown in Figures 2C and D. The overlap between the flange portion 41 and the bottom surface portion 21 is released, and part of the flange portion 41 protrudes from the bottom surface portion 21. As a result, it is possible to prevent the plate materials w1, w1 sandwiched between the protruding flange portion 41 and the eaves portion 23 from coming loose.

Since the plates w1, w1 can be bound by operating from one side, they can be attached even when hands or tools cannot reach the back side of the plates w1, w1. Even if the plates w1, w1 are bent to form a long rectangular column, they can be bound without having to reach inside the column with hands or tools. Also, by turning the rotating knob 40 90° and returning it to the unlocked state (initial state), the fastener 1 and the plates w1, w1 can be easily separated.

The knob portion 43 also has a half-moon shaped groove 44, into which a tool (not shown) can be inserted to rotate the knob portion 43. By visually checking the rotational position of the knob portion 43, it is possible to determine whether the knob portion 43 is locked or unlocked.

Next, the details will be explained.
[Structure for maintaining the rotated state of the rotary knob 40]
A structure for maintaining the rotation state when the rotating knob 40 is rotated 90° will be described with reference to FIG. 3. FIG. 3A is a perspective view showing only the shaft 42 and the knob 43 from below with the flange 41 removed. A protrusion 47 extending from the lower surface of the knob 43 is provided on the shaft 42 on the lower side of the knob 43. On the other hand, as shown in FIG. 3B, the inner curved wall 28 of the shaft insertion parts 26, 26 has a curved surface that widens toward both ends of the arc. FIG. 3C is a cross section showing the relationship between the shaft 42 and the shaft insertion parts 26, 26 before locking. When the knob 43 is rotated, the protrusion 47 acts to push the pair of shaft insertion parts 26, 26 apart along the inner curved wall 28, accumulating a resilient force (FIG. 3D, arrow R), and when the knob 43 is rotated 90°, the accumulated resilient force is released and the protrusion 47 fits into the groove 32 (FIG. 3E). This allows the knob portion 43 to be held in a rotated state of 90°. By providing the inner curved wall 28, the interference of the protrusion 47 is reduced when the knob portion 43 is rotated, allowing the initial movement to be performed with a light operation and improving the feeling of decisiveness when the rotation is completed.

The function of maintaining the rotated state is also achieved by the upper edge 29 of the shaft insertion portions 26, 26 and the knob portion 43. The size of the central portion 29a is adjusted to match the knob portion 43. In FIG. 4B, in the process of rotating the knob portion 43 by 90 degrees, the knob portion 43 climbs the inclined surface 29b and overcomes the ridge 29c. When the knob portion 43 is positioned at the central portion 29a, both sides of the knob portion 43 are sandwiched between the ridges 29c, and the rotated state is maintained.

[Connection between main body box 20 and rotating knob 40]
In FIG. 4A, the pair of shaft insertion parts 26, 26 have a certain thickness, and their shape is a shape of a cylinder divided vertically in two. By dividing them in this way, the pair of shaft insertion parts have elasticity that tends to return to their original shape in the opening direction. Each shaft insertion part 26, 26 is provided with a burr 31 that protrudes in the circumferential direction so as to narrow the gap between them. The burr 31 is provided with an inclined surface 31a that is inclined from the bottom surface part 21 toward the upper edge 29 of the shaft insertion parts 26, 26 so as to approach the other shaft insertion part 26. When the knob part 43 of the rotating knob 40 is inserted from the rear surface of the bottom surface part 21 to the shaft part 42, as the knob part 43 enters between the pair of shaft insertion parts 26, 26, the knob part 43 hits the inclined surface 31a, and the pair of shaft insertion parts 26, 26 are pushed in the opening direction (arrow S) to accumulate elastic force. Because of the inclined surface 31a, it is easy to push the shaft insertion parts 26, 26 apart. When the knob part 43 passes through the range where the burr 31 is provided and reaches the upper side of the upper edge 29 of the shaft insertion parts 26, 26, the knob part 43 becomes rotatable. The elastic force stored in the shaft insertion parts 26, 26 is released, and the pair of shaft insertion parts 26, 26 return to their original shape. The knob part 43 can no longer come out of the shaft insertion parts 26, 26 due to the burr 31, and the rotating knob 40 and the main box 20 are integrated as the fastener 1. At this time, the flange part 41 overlaps within the range of the shape of the bottom surface part 21 and is left on the back side of the bottom surface part 21.

[Structure that draws the plates sandwiched between the flange and eaves together]
In Fig. 5A, the surface of the flange 41 on the knob 43 side is provided with a first tapered surface 41d that rises inward along a pair of straight sides 41a, 41a so as to increase the thickness of the flange 41. A cross-sectional view of the flange 41 taken along line X-X (see Fig. 1B) is shown in Fig. 4C. In addition, an inclined surface 29b is also provided on the upper edge 29 of the shaft insertion portions 26, 26.

In FIG. 5B, the fastener 1 is inserted into the insertion hole 50 from the flange 41 and bottom surface 21 with the angle of the insertion hole 50 and the bottom surface 21 adjusted to a predetermined first angle. The fastener 1 is inserted from one side of the plate materials w1, w1. The figure also shows that the fastener 1 is inserted into the insertion hole 50 with a gap between the plate materials w1, w1 to be bound. When the knob portion 43 is rotated by a predetermined second angle (90°), the knob portion 43 ascends the inclined surface 29b, and the flange portion 41 approaches the bottom surface 21. In addition, during the process of the rotation of the flange portion 41, the end of the first tapered surface 41d engages with the plate materials w1, w1, and the inclination of the first tapered surface 41d draws the plate materials w1, w1 together. This action allows the thickness of the binding strip to be corrected to the set thickness.

[Structure for reducing protrusions from the front and back surfaces of plate material]
In FIG. 5C, in this embodiment, the distance d2 from the position where the shaft portion 42 rises to the top surface of the knob portion 43 is within the range of the distance d3 from the lower surface of the bottom portion 21 to the outside of the eaves portion 23. Therefore, when the knob portion 43 is rotated to the second angle, it fits within the range from the bottom portion 21 of the main body box 20 to the eaves portion 23 and does not protrude from the eaves portion 23 in the z direction. Therefore, it is possible to prevent rotation and damage due to unintended external forces. In addition, on the arc sides 41b, 41b side of the flange portion 41, a second tapered surface 41e is provided that reduces the step between the back side of the first tapered surface 41d and the plate material w1, w1. This also contributes to preventing rotation and damage due to external forces (not shown).

The above describes an embodiment of a fastening structure in which the shape of the bottom surface portion 21 and the insertion hole 50 is rectangular, but other shapes such as elliptical, oval (track), or polygonal may be used. When the knob portion 43 is rotated to shift a predetermined angle, there is only a portion where the bottom surface portion 21 and the insertion hole 50 do not overlap in a plan view. Depending on the shape of the bottom surface portion 21 and the insertion hole 50, the difference between the predetermined first angle and the second angle may not be limited to 90°. For example, when the bottom surface portion 21 and the insertion hole 50 are equilateral triangles, the difference between the predetermined first angle and the second angle is 30°. In addition, the shape of the bottom surface portion 21 and the insertion hole 50 should be avoided to be circular so that the main box 20 does not rotate when the knob portion 43 is rotated.

The fastening structure of the embodiment described above allows plates to be fastened together from one direction, minimizing protrusions from the front and back surfaces of the plates, and allows them to be easily disassembled and disposed of separately after use.

REFERENCE SIGNS LIST 1 fastener 20 main box 21 bottom surface 22 side surface 23 eaves 24 circular hole 25 rectangular hole 26 shaft insertion portion 27 arc-shaped wall 28 internally curved wall 29 upper edge 29a central portion 29b inclined surface 29c convex strip 30 composite hole 31 burr 31a inclined surface 32 groove 41 flange 41a straight edge 41b arc-shaped edge 41d first tapered surface 41e second tapered surface 42 shaft 43 knob portion 44 groove 47 protrusion 50 insertion hole d1 distance d2 distance w1 plate material

Claims (6)

a main body box including a bottom surface portion passing through a composite hole formed by overlapping a circular hole and a rectangular hole whose short side is shorter than the diameter of the circular hole and whose long side is longer than the diameter of the circular hole with their centers aligned, a side surface portion rising up around the entire circumference of the bottom surface portion, a visor portion protruding outwardly from the upper edge of the side surface portion along the entire circumference in parallel with the bottom surface portion, and a pair of shaft insertion portions rising up from the bottom surface portion on either side of the circular hole;
a flange portion large enough to cover almost the entire bottom surface portion; a shaft portion rising from the center of the flange portion and having a diameter equal to the diameter of the circular hole; a knob portion that is a rectangular parallelepiped and provided on the top of the shaft portion and has a planar shape that can pass through the rectangular hole, and the knob portion is inserted into the composite hole from the knob portion to the shaft portion while the flange portion is left overlapping and within the range of the shape of the bottom surface portion on the back side of the bottom surface portion, and the knob portion is located above the upper edges of the pair of shaft insertion portions;
a plurality of plate materials to be bound, each of which has an insertion hole formed therein, the insertion hole having a shape that allows the plate materials to pass when the orientation of the bottom surface portion is at a first angle and does not allow the plate materials to pass when the orientation of the bottom surface portion is not at the first angle;
A fastening structure characterized in that the flange portion and bottom portion are inserted into multiple plate materials with the insertion holes aligned and overlapped from one side of the plate materials, and by rotating the knob portion from a first angle to a second angle, the overlap between the flange portion and the bottom portion is released and the multiple plate materials are sandwiched between the flange portion and the eaves portion.
2. The fastening structure of claim 1, wherein a protrusion is provided on the shaft portion below the knob portion, while a pair of shaft insertion portions are provided with grooves into which the protrusion fits when the knob portion is rotated from a first angle to a second angle.
2. The fastening structure of claim 1, wherein the upper edge of the shaft insertion portion is provided with an inclined surface that is higher in the center and descends toward both ends, the center portion is flat, and both sides of the center portion are surrounded by convex strips that are slightly higher than the center portion, and the width of the center portion is equal to the length of the short side of the rectangular hole.
2. The fastening structure of claim 1, wherein a pair of shaft insertion portions are provided with burrs protruding in the circumferential direction of the circular hole so as to narrow the distance between them, and the burrs are provided with an inclined surface that is inclined from the bottom surface portion toward the upper edge of the shaft so as to approach the other shaft insertion portion.
2. The fastening structure of claim 1, wherein the bottom surface is rectangular, the flange has a pair of straight sides overlapping with the long sides of the bottom surface, and a first tapered surface is provided that rises inward along the pair of straight sides so as to increase the thickness of the flange.
2. The fastening structure according to claim 1, wherein the knob portion has a height that is within a range from the bottom surface portion to the eaves portion when rotated to a second angle.