Bolt caps and jigs used therewith

Abstract

To provide a bolt cap that can be oriented in a uniform direction and can enhance design. [Solution] A bolt cap 11 having a cap 17 that covers the head 15 of a bolt 13, and a washer 19 that is passed through the shank 14 of the bolt 13, wherein the cap 17 is formed in a cylindrical shape with a bottom that covers the head 15 with an inner space, and a pair of locking portions 41 that protrude radially inward are formed at equal intervals around the circumferential direction on the inner circumference of the opening edge, a conical spring 45 is attached coaxially to the inner surface of the bottom plate portion 29, and a jig insertion recess 31 is formed on the outer surface 30 of the bottom plate portion 29, the washer 19 is formed in an annular shape with a bolt hole 35 through which the shank 14 is inserted, and a plurality of rotation-restricting protrusions 47 are formed circumferentially on the underside of the washer facing the seating surface, and a pair of lockable pieces 39 that protrude outward from the outer circumferential edge and sandwich the locking portion 41 between them are formed at equal intervals around the circumferential direction.

Description

[Technical Field]

[0001] The present invention relates to a bolt cap and a jig for use therewith. [Background technology]

[0002] Furniture such as chairs and open shelves are generally assembled by the user for ease of delivery. In this case, if a design that allows for easy assembly and cost are prioritized, a method of assembling the furniture from the outside is often used. Bolts and screws are generally used for assembling furniture from the outside. Patent Document 1 discloses a screw with a decorative cap in which a vertical hole is formed in the head of the screw and the stem portion of the decorative cap is press-fitted into the vertical hole. Patent Document 2 discloses a screw head cover in which the cap body is connected to a washer member with a thin string and the inner edge of the cap body engages with the underside of the outer edge of the screw head. Patent Document 3 discloses a bolt cap that uses two washers, one large and one small, stacked on top of each other and covers the bolt by hooking the cap onto the large washer.

[0003] Patent Document 4 discloses a rust-preventing bolt cap in which a bottom plate portion is passed through the bolt before the nut is attached to the bolt, and after the nut is tightened, the nut is covered with a cap portion and bonded to the bottom plate portion. Patent Document 5 discloses an internally threaded screw and a covering cap that can easily attach and detach various dedicated metal fittings that have male threads that fit the female threads of the internally threaded screw, and that covers the head of the internally threaded screw with a covering cap to make the presence of the internally threaded screw less noticeable when it is not in use. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 56-135509 [Patent Document 2] Japanese Utility Model Application Publication No. 59-7908 [Patent Document 3] Japanese Utility Model Application Publication No. 61-32612 [Patent Document 4] Japanese Utility Model Application Publication No. 06-28325 [Patent Document 5] Japanese Patent Application Publication No. 11-117924 Summary of the Invention [Problem to be solved by the invention]

[0005] However, because screws are generally fastened by rotation, the direction of rotation upon completion of tightening (assembly) cannot be specified, and the directionality (rotational position) of the head design cannot be aligned. For example, there is the issue of not being able to determine the direction when the screw has a concave shape such as a Phillips or Minus groove. Particularly when multiple screws are used, they do not all align in the same direction (rotational position) upon completion of tightening. Meanwhile, screw hole cover stickers with wood grain designs are also known to be used to hide the screw heads, but the cumbersome process of applying the stickers and the lack of design quality present issues. Additionally, decorative bolts with beautifully finished screw heads are also known, but the rotational position cannot be controlled and the directionality cannot be aligned.

[0006] The present invention was made in consideration of the above situation, and its purpose is to provide a bolt cap and a jig to be used therewith that can be aligned in direction and have an improved design. [Means for solving the problem]

[0007] Next, means for solving the above problems will be described with reference to the drawings corresponding to the embodiments. The bolt cap 11 according to claim 1 of the present invention is a bolt cap 11 having a cap 17 that covers the head 15 of a bolt 13 and a washer 19 that is passed through the shank 14 of the bolt 13, The cap 17 is The head 15 is formed in a cylindrical shape with a bottom, with an inner space surrounding the head 15. A pair of locking portions 41 projecting radially inward are formed at equal intervals around the circumferential direction on the inner periphery of the opening edge. A conical spring 45 is coaxially attached to the inner surface of the bottom plate portion 29. A jig insertion recess 31 is formed on the outer surface 30 of the bottom plate portion 29. The washer 19 is The shaft portion 14 is formed in an annular shape having a bolt hole 35 through which the shaft portion 14 is inserted. A plurality of rotation restricting protrusions 47 are formed in the circumferential direction on the underside of the washer facing the seating surface, A pair of locking pieces 39 are formed at equal intervals in the circumferential direction, protruding outward from the outer periphery and sandwiching the locking portion 41 between themselves and the seating surface.

[0008] In this bolt cap 11, the shank 14 of the bolt 13 is inserted into the bolt hole 35 of the washer 19. The washer 19 with the shank 14 inserted is then inserted into the bolt through hole 27 formed in the mounting material 21. The shank 14 inserted into the mounting material 21 is screwed into a countersunk nut 37 embedded in the mounting base material 23 to which the mounting material 21 is to be attached. In this way, the mounting material 21 is fixed to the mounting base material 23 by the bolt 13. The washer 19 has a rotation restricting protrusion 47 that protrudes from its underside. When the bolt 13 is tightened, the rotation restricting protrusion 47 enters the seating surface of the workpiece 23 and restricts the rotation of the washer 19 that accompanies the tightening of the bolt 13. In other words, the washer 19 allows the orientation of the locking pieces 39 provided on the outer periphery to be set to any position in the rotational direction. Here, an example will be described in which a pair of locking pieces 39 are arranged horizontally on the left and right of a vertical seating surface formed on the workpiece 21. As an example, a hexagon socket head bolt 13 is preferably used as the bolt 13. This is used when it is desired to embed and accommodate the head 15 of the bolt 13 in a counterbore hole and improve the design of the surface of the mounting material 21. Note that if the bolt cap 11 is to protrude from the surface of the mounting material 21, a normal hexagon bolt with a hexagonal head 15 may be used. The head 15 of the bolt 13 that secures the mounting member 21 is covered with a cap 17. When the cap 17 is placed on the head 15, the conical spring 45 comes into contact with the head 15 of the bolt 13. When the cap 17 is pressed toward the head 15, the conical spring 45 is elastically deformed, and the opening edge comes into contact with the seating surface. In this state, the cap 17 is rotated by operating the jig insertion recess 31 formed on the outer surface 30 using the bolt cap jig 33. When the cap 17 is rotated, the pair of locking portions 41 protruding inward from the inner periphery of the opening edge enter the gap between the locking pieces 39 and the seating surface. In other words, the locking portions 41, which are arranged vertically and pressed into the locking pieces 39 located in the left-right direction, are rotated 90° and placed on the locking pieces 39. When the cap 17 is released from being pressed, the elastic restoring force of the conical spring 45 presses the locking portion 41 against the locking piece 39 of the washer 19, restricting rotation. This rotation-restricting force is obtained by the frictional force between the locking surfaces of the locking piece 39 and the locking portion 41. If an uneven portion is provided across both locking surfaces, a clicking sensation can be generated at the desired locking position (overlapping position), improving operability. In this case, the rotation-restricting force is also increased, making it more difficult to disengage the locking piece 39 and the locking portion 41. In this way, with the bolt cap 11, by positioning the locked piece 39 of the washer 19 in advance, the rotational direction of the cap 17 can be determined accordingly. This aligns the direction of the cap 17, improving the design.

[0009] The bolt cap 11 according to claim 2 of the present invention is the bolt cap 11 according to claim 1, The seat surface is a counterbore surface 25 that is coaxial with the bolt through hole 27 of the mounting member 21 and has an inner diameter that is substantially the same as the outer diameter of the cap 17, The depth of the counterbore surface 25 is approximately the same as the height of the cap 17 in the axial direction.

[0010] In this bolt cap 11, the depth of the countersunk surface 25 is formed to be approximately the same as the height in the axial direction of the cap 17. As a result, when the conical spring 45 elastically returns to its original position while the engaged piece 39 and the engaging portion 41 are engaged with each other, the outer surface 30 of the cap 17 becomes flush with the surface of the mounting material 21. The bolt cap 11 is structured so that when the opening edge of the cap 17 abuts against the counterbore surface 25 and the cap 17 is rotated, the latched piece 39 and the latching portion 41 latch together. If a slight clearance is provided between the latching surfaces of the latched piece 39 and the latching portion 41 to improve operability, the height of the cap 17 may be slightly reduced by the amount of that clearance. In this case, when the cap 17 is completely attached, the elastic force of the conical spring 45 pushes the cap 17 back, and with the latching surfaces pressed together, the outer surface 30 of the cap 17 becomes flush with the surface of the mounting material 21. In this way, with the bolt cap 11, the cap 17 can be housed flush with the mounting material 21, which aligns the direction of the cap 17 and makes the bolt 13 less noticeable, further enhancing the design. Furthermore, because the cap 17 is housed flush with the mounting material 21, it is possible to prevent tampering by removing the cap 17. Furthermore, by rotating the bolt cap jig 33, the elastic restoring force of the conical spring 45 can cause the cap 17 to pop out of the countersunk hole, so even if the cap 17 is embedded in the countersunk hole flush with the mounting material 21, it can be easily removed.

[0011] The bolt cap jig 33 according to claim 3 of the present invention is a bolt cap jig 33 for rotating the cap 17 according to claim 1 or claim 2, A feature of this embodiment is that an operating protrusion 67 that fits into the jig insertion recess 31 and can rotate the cap 17 around the cylindrical axis is provided on a jig body 69 that is held by hand.

[0012] In this bolt cap jig 33, the jig body 69 has an operation protrusion 67. The bolt cap jig 33 is grasped with fingers on both sides in the thickness direction, and the operation end surface on the short side is directed toward the outer surface 30 of the cap 17. This operation end surface is provided with the above-mentioned operation protrusion 67 that fits into the jig insertion recess 31 provided in the outer surface 30 of the cap 17. A plurality of types of bolt cap jigs 33 can be produced to correspond to the variations in the jig insertion recess 31. In this case, the operation convex portion 67 provided on the operation end surface of the jig body 69 is formed with a convex portion shape and a convex portion position corresponding to the concave portion shape and concave portion position of each of the variations. The bolt cap jig 33 having such a configuration can rotate the cap 17 by inserting the operating protrusion 67 into the jig insertion recess 31 of the cap 17, and can release the locking portion 41 of the cap 17 from the locking piece 39 of the washer 19 by accessing only from the surface of the mounting material 21. [Effects of the Invention]

[0013] According to the bolt cap of claim 1 of the present invention, even if the bolt is tightened (assembly completed) in any rotation direction, the rotation direction of the cap covering the head of the bolt can be set to the desired position. Therefore, especially when multiple bolts are used, the design direction of each cap of each bolt can be aligned, which can enhance the design when used in furniture, for example.

[0014] According to the bolt cap of claim 2 of the present invention, the cap can be accommodated inside the counterbore and the outer surface of the cap is flush with the surface of the mounting material, which further enhances the design and prevents tampering with the cap. Even if the bottom plate of the cap is flush with the surface of the mounting material, the elasticity of the conical spring allows the cap to pop out of the counterbore and be easily removed.

[0015] According to the bolt cap jig of claim 3 of the present invention, the cap can be removed by inserting the operating protrusion into the jig insertion recess of the cap, rotating the cap and releasing the locking part of the cap from the locking piece of the washer. Since the bolt cap jig can be accessed only from the surface of the mounting material, a cap attachment / detachment structure can be achieved in which the cap is held flush with the surface of the mounting material. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 2 is an exploded perspective view of the bolt cap according to the embodiment. [Figure 2] FIG. [Figure 3] FIG. 3 is a cross-sectional plan view of the cap and washer shown in FIG. 2. [Figure 4] FIG. 1 is a perspective view showing a chair as an example of furniture together with an enlarged view of a main part. [Figure 5] FIG. 1 is a perspective view showing an open shelf as an example of furniture, together with an enlarged view of a main part. [Figure 6] FIG. 4 is a cross-sectional plan view of the bolt mounting portion before the bolt is mounted. [Figure 7] FIG. 10 is a cross-sectional plan view of the bolt mounting portion after the bolt has been fastened. [Figure 8] FIG. 10 is a cross-sectional plan view of the bolt mounting portion before the cap is mounted. [Figure 9] 9 is a cross-sectional view taken along the line AA in FIG. 8. [Figure 10] FIG. 2 is a perspective view of a bolt cap jig before it is inserted into a bolt mounting portion. [Figure 11] FIG. 10 is a perspective view of the bolt cap jig after insertion. [Figure 12] 9 is an explanatory view of the operation when the cap is in the middle of rotation, taken along the cross section AA of FIG. 8. FIG. [Figure 13] 9 is an explanatory view of the operation when the cap has completed rotation in the AA cross section of FIG. 8. FIG. [Figure 14] This is a cross-sectional plan view of the bolt cap after the cap has been attached by the elastic return of the conical spring. [Figure 15] 10A to 10F are perspective views showing modified examples of the cap. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view of a bolt cap 11 according to this embodiment. The bolt cap 11 according to this embodiment has a cap 17 that covers the head 15 of the bolt 13, and a washer 19 that is passed through the shank 14 of the bolt 13. The bolt cap 11 is used when bolting a mounting member 21 to a mounting target member 23 (see FIG. 6 ) in furniture or the like. The bolt 13 may be a hexagonal bolt or a hexagonal socket bolt. In this embodiment, the bolt 13 will be described as a hexagonal socket bolt having a hexagonal hole formed in the center of the head 15 that is formed in the shape of a thin disk. However, the bolt 13 is not limited to this and may be a screw or a screw.

[0018] Furthermore, the surface of the mounting member 21 (also referred to as the bearing surface) to which the bolt 13 is fastened may be a flat surface or a counterbore. In this embodiment, the counterbore surface 25 will be described as an example of a bearing surface. The counterbore surface 25 is formed coaxially with the bolt through hole 27 of the mounting member 21 and has an inner diameter substantially equal to the outer diameter of the cap 17. The depth of the counterbore surface 25 is substantially equal to the height of the cap 17 in the axial direction. In this embodiment, a cap mounting structure will be described as an example in which the cap 17 is received in the counterbore hole and the outer surface 30 is flush with the surface of the mounting member 21. Note that the bolt cap 11 may be used in a mounting structure in which the outer surface 30 of the cap 17 is not flush with the surface of the mounting member 21, but rather the outer surface 30 of the cap 17 protrudes from the surface. For example, the outer surface 30 may not be flat but may be formed into a gentle dome-like bulge.

[0019] The cap 17 is formed in a cylindrical shape with a bottom that covers the head 15 with an internal space. The cap 17 has a jig insertion recess 31 formed on an outer surface 30 of a bottom plate portion 29. As an example, the jig insertion recess 31 can be a plurality of small-diameter circular recesses, for example, two small-diameter circular recesses, formed side by side in the diameter direction on the outer surface 30 of the cap 17, which is formed in a cylindrical shape with a bottom. By using the jig insertion recess 31, the cap 17 can be rotated by a bolt cap jig 33 (see FIG. 10 ), which will be described later. In other words, the jig insertion recess 31 is configured to restrict relative rotation with the bolt cap jig 33.

[0020] The washer 19 is formed in an annular shape with a bolt hole 35 through which the shank 14 is inserted. The shank 14 inserted through the bolt hole 35 is then inserted into a bolt through hole 27 formed coaxially in the counterbore surface 25. The male thread of the shank 14 inserted into the bolt through hole 27 is threaded into a countersunk nut 37 (see FIG. 6) embedded in the workpiece 23. The washer 19 is formed with a pair of locking pieces 39 that protrude outward from the outer periphery at equal intervals in the circumferential direction. The locking pieces 39 are formed at an angle from the outer periphery of the washer 19 in a direction away from the counterbore surface 25. In other words, when the washer 19 comes into contact with the counterbore surface 25, a gap is formed between the counterbore surface 25 and the locking pieces 39. A locking portion of the cap 17, which will be described later, enters this gap.

[0021] Fig. 2 is an exploded perspective view of the cap 17 and the washer 19. Fig. 3 is a plan cross-sectional view of the cap 17 and the washer 19 shown in Fig. 2. The cap 17 has a pair of locking portions 41 that protrude radially inward and are formed at equal intervals around the circumferential direction on the inner periphery of the opening edge opposite the bottom plate portion 29. As shown in FIG. 3, these locking portions 41 have an inclined locking surface 43 that gradually approaches the inner circumferential surface of the cap 17 as it extends from the inner periphery of the opening edge of the cap 17 toward the bottom plate portion 29. A conical spring 45 is coaxially attached to the inner surface of the bottom plate portion 29 of the cap 17. This conical spring 45 abuts against the head 15 of the bolt 13. The conical spring 45 can reduce its height when compressed. This allows the thickness (height) of the cap 17 to be set small.

[0022] Washer 19 has a plurality of rotation-restricting protrusions 47 formed in the circumferential direction on its underside, which faces seat surface 25. When washer 19 is tightened by head 15 of bolt 13, these rotation-restricting protrusions 47 are pressed into countersunk surface 25. This restricts washer 19 from rotating when the bolt is tightened. In other words, rotation-restricting protrusions 47 prevent washer 19 itself from rotating. This rotation restriction allows the orientation of outer surface 30 of cap 17 to be unified, for example, by aligning the positions of the two jig insertion recesses 31 horizontally.

[0023] As described above, the locked piece 39 is formed at an angle, so when the washer 19 seats on the counterbore surface 25, a gap is created between the washer 19 and the counterbore surface 25. The locking portion 41 of the cap 17, which is being rotated, enters this gap. When the locking portion 41 enters the gap, the locking surface 43 comes into contact with the locked surface 49 of the locked piece 39, preventing the cap 17 from coming off the washer 19. At this time, in the bolt cap 11, the conical spring 45 is compressed by the head 15 of the bolt 13, so the elastic restoring force of the conical spring 45 presses the locking surface 43 against the locked surface 49, enabling a secure lock without any rattle.

[0024] FIG. 4 is a perspective view showing a chair 51 as an example of furniture together with an enlarged view of a main part. An example of furniture in which bolt caps 11 are used is chair 51. In chair 51, bolt caps 11 are used to secure, for example, legs 55 to both sides of seat frame 53. Bolt 13 and washer 19 are received in counterbore holes formed on both sides of leg 55. Cap 17 covers head 15 of bolt 13 and engages washer 19, and is received in the counterbore hole with outer surface 30 flush with the surface of the furniture (leg 55). By using bolt caps 11 in chair 51, the orientation of outer surface 30 of each cap 17 in the counterbore hole can be aligned. In the case of chair 51 shown in FIG. 4, two jig insertion recesses 31 can be positioned horizontally, and the jig insertion recesses 31 of the other caps 17 can also be aligned horizontally.

[0025] FIG. 5 is a perspective view showing an open shelf 57, which is an example of furniture, together with an enlarged view of a main part. Another example of furniture in which bolt caps 11 are used is an open shelf 57. In the open shelf 57, bolt caps 11 are used to secure a top panel 61, a bottom panel 63, and a shelf panel 65 to a side panel 59. A bolt 13 and a washer 19 are received in a counterbore formed in the side panel 59. A cap 17 covers the head 15 of the bolt 13 and engages with the washer 19, and is received in the counterbore with its outer surface 30 flush with the surface of the furniture (side panel 65). By using bolt caps 11, the open shelf 57 can align the outer surfaces 30 of the caps 17 in the counterbore. In the case of the open shelf 57 shown in FIG. 5, two jig insertion recesses 31 can be positioned horizontally, and the jig insertion recesses 31 of the other caps 17 can also be aligned horizontally. As shown in the figure, the orientation of the jig insertion recesses 31 is aligned in all of the caps 17 in multiple locations.

[0026] Next, the procedure for fixing the mounting material 21 using the bolt cap 11 will be described.

[0027] FIG. 6 is a cross-sectional plan view of the bolt mounting portion before the bolt is mounted. To attach the bolt cap 11, first align the bolt through-hole 27 with the countersunk nut 37 of the workpiece 23. Next, insert the bolt 13, with the shank 14 passing through the washer 19, into the bolt through-hole 27.

[0028] FIG. 7 is a cross-sectional plan view of the bolt mounting portion after the bolt has been fastened. The bolt 13 is threaded into the countersunk nut 37 using a tool such as a hex wrench. By tightening the bolt 13, the mounting member 21 is fixed to the mounted member 23. At this time, the washer 19 is pressed against the head 15 of the bolt 13, and the rotation restricting protrusion 47 is forced into the countersunk surface 25. This restricts the washer 19 from rotating together with the bolt 13, and the washer 19 remains set in, for example, an initial rotation position, for example, with the retained pieces 39 in the left and right positions as shown in the figure.

[0029] Fig. 8 is a plan cross-sectional view of the bolt mounting portion before the cap is mounted, and Fig. 9 is a cross-sectional view taken along line AA in Fig. 8. Next, cap 17 is inserted into the countersunk hole. At this time, the rotation position of cap 17 is such that locking portion 41 of cap 17 is rotated 90° with respect to locking piece 39 of washer 19, as shown in Figure 9. This allows cap 17 to be inserted into the countersunk hole without locking portion 41 interfering with locking piece 39, and with the insertion tip abutting countersunk surface 25, outer surface 30 is flush with the surface of mounting material 21.

[0030] Fig. 10 is a perspective view of the bolt cap jig 33 before it is inserted into the bolt mounting portion, and Fig. 11 is a perspective view of the bolt cap jig 33 after it has been inserted. Next, the cap 17 housed in the countersunk hole is rotated using a bolt cap jig 33. The bolt cap jig 33 that rotates the cap 17 has an operating protrusion 67 provided on a jig body 69 that fits into the jig insertion recess 31 of the cap 17 and rotates the cap 17 around its axis.

[0031] Here, the bolt cap jig 33 has a jig body 69 formed in the shape of, for example, a flat rectangular parallelepiped that can be held by hand. The jig body 69 is grasped with fingers on both sides in the thickness direction, and the operation end surface on the short side faces the outer surface 30 of the cap 17. This operation end surface is provided with an operation protrusion 67 that fits into the jig insertion recess 31 provided on the outer surface 30 of the cap 17.

[0032] The bolt cap jig 33 can rotate the cap 17 about the cylindrical axis by fitting the operation protrusion 67 into the jig insertion recess 31 of the cap 17. In this embodiment, the jig insertion recess 31 is two circular recesses formed side by side in the diameter direction on the outer surface 30 of the bottomed cylinder. Therefore, the operation protrusion 67 is formed by two circular protrusions spaced the same distance apart as the two circular recesses. The bolt cap jig 33 has a flat jig body 69, which makes it easy to grip both sides perpendicular to the surface of the mounting material 21 and push and turn the cap 17.

[0033] Fig. 12 is an explanatory view of the operation when the cap 17 is in the middle of rotation in the AA cross section of Fig. 8. Fig. 13 is an explanatory view of the operation when the cap 17 has completed rotation in the AA cross section of Fig. 8. When the cap 17 is rotated by the bolt cap jig 33, the bolt cap 11 enters the gap between the locking piece 39 and the counterbore surface 25 in the rotation direction (e.g., clockwise) shown in Fig. 12. The rotation direction may be either forward or reverse. When the cap 17 is rotated 90°, the locking portion 41 completely overlaps the locking piece 39 of the washer 19, as shown in Fig. 13.

[0034] FIG. 14 is a cross-sectional plan view of the bolt cap 11 after the attachment of the cap 17 has been completed by the elastic return of the conical spring 45. When the operating protrusion 67 of the bolt cap jig 33 is removed from the jig insertion recess 31 of the cap 17 while the locking portion 41 is locked to the locking piece 39, the conical spring 45 of the cap 17 elastically returns to its original position. When the conical spring 45 elastically returns to its original position, the bottom plate portion 29 of the cap 17 is pressed in a direction away from the head portion 15. As a result, the locking surface 43 of the cap 17 is pressed against the locking surface 49 of the locking piece 39, and the cap 17 is firmly attached to the washer 19 without any rattle. In this state, the high frictional force between the locking piece 39 and the locking portion 41, which are pressing against each other, restricts easy rotation of the cap 17.

[0035] Next, a modification of the cap 17 will be described.

[0036] FIG. 15 is a perspective view showing modified examples of the cap 17 in (a) to (f). The jig insertion recess 31 of the cap 17 can be changed in various ways to correspond to the design of the mounting member 21. In this case, it is not necessary to change the locking portion 41 and the locked piece 39. In other words, the cap 17 can remain with the pair of left and right locking portions 41.

[0037] As an example of a modified example of the jig insertion recess 31 in the cap 17, for example, as shown in Fig. 15(a), it may be a plurality of circular recesses, for example, three, formed in the diameter direction on the outer surface 30 of the cap 17, which is formed in a cylindrical shape with a bottom. Alternatively, as shown in Fig. 15(b), it may be a plurality of circular recesses, for example, three, formed at equal intervals in the circumferential direction of the outer surface 30.

[0038] As shown in Figures 15(c) and 15(d), the jig insertion recess 31 may be a hexagonal or cross-shaped recess formed in the center of the outer surface 30. By forming the jig insertion recess 31 as a hexagonal or cross-shaped recess, tools for rotating the bolt 13, such as a hex wrench or a Phillips head screwdriver, can be used. As shown in Figure 15(e), the jig insertion recess 31 may be a diametric groove-shaped recess passing through the center of the outer surface 30. This groove-shaped recess 31 may be gradually deeper from both ends of the groove length toward the center of the groove. This groove-shaped recess 31 allows the cap 17 to be rotated using, for example, the edge of a coin. Furthermore, as shown in Figure 15(f), the groove-shaped recess may be formed as multiple short parallel groove-shaped recesses sandwiching a diametric groove-shaped recess.

[0039] A plurality of types of bolt cap jigs 33 can be produced to correspond to each of the variations of the jig insertion recess 31. In this case, the operation convex portion 67 provided on the operation end surface of the jig body 69 is formed with a convex portion shape and a convex portion position corresponding to the concave portion shape and concave portion position of each of the variations.

[0040] Next, the operation of the above-described configuration will be described.

[0041] In the bolt cap 11 according to this embodiment, the shank 14 of the bolt 13 is inserted into the bolt hole 35 of the washer 19. The washer 19 with the shank 14 inserted therethrough is then inserted into the bolt through-hole 27 formed in the mounting material 21. The shank 14 inserted into the mounting material 21 is threaded into a countersunk nut 37 embedded in the mounting base material 23 to which the mounting material 21 is to be attached. In this way, the mounting material 21 is fixed to the mounting base material 23 by the bolt 13.

[0042] The washer 19 has a rotation restricting protrusion 47 that protrudes from its underside. When the bolt 13 is tightened, the rotation restricting protrusion 47 enters the seating surface of the workpiece 23 and restricts the rotation of the washer 19 that accompanies the tightening of the bolt 13. In other words, the washer 19 allows the orientation of the locking pieces 39 provided on its outer periphery to be set to any position in the rotational direction. The orientation of this washer 19 determines the locking position of the locking portion 41. Here, an example will be described in which a pair of locking pieces 39 are arranged horizontally on the left and right of a vertical seating surface formed on the workpiece 21.

[0043] As an example, a hexagon socket head bolt 13 is preferably used as the bolt 13. This is used when it is desired to embed and accommodate the head 15 of the bolt 13 in a counterbore hole and improve the design of the surface of the mounting material 21. Note that if the bolt cap 11 is to protrude from the surface of the mounting material 21, a normal hexagon bolt with a hexagonal head 15 may be used.

[0044] The head 15 of the bolt 13 that secures the mounting member 21 is covered with a cap 17. When the cap 17 is placed on the head 15, the conical spring 45 comes into contact with the head 15 of the bolt 13. When the cap 17 is pressed toward the head 15, the conical spring 45 is elastically deformed, and the opening edge comes into contact with the seating surface.

[0045] In this state, the cap 17 is rotated by operating the jig insertion recess 31 formed on the outer surface 30 of the bottom plate portion 29 using a bolt cap jig 33. When the cap 17 is rotated, a pair of locking portions 41 protruding inward from the inner periphery of the opening edge enters the gap between the locking pieces 39 and the seating surface. In other words, the locking portions 41, which are arranged vertically and pressed into the locking pieces 39 located in the left-right direction, are rotated 90° and placed on the locking pieces 39.

[0046] When the cap 17 is released from being pressed, the elastic restoring force of the conical spring 45 presses the locking portion 41 against the locking piece 39 of the washer 19, restricting rotation. This rotation-restricting force is obtained by the frictional force between the locking surfaces of the locking piece 39 and the locking portion 41. If an uneven portion is provided across both locking surfaces, a clicking sensation can be generated at the desired locking position (overlapping position), improving operability. In this case, the rotation-restricting force is also increased, making it more difficult to disengage the locking piece 39 and the locking portion 41.

[0047] In this way, with the bolt cap 11, by positioning the locked piece 39 of the washer 19 in advance, the rotational direction of the cap 17 can be determined accordingly. This aligns the direction of the cap 17, improving the design.

[0048] Furthermore, in this bolt cap 11, the depth of the countersunk surface 25 is formed to be approximately the same as the height in the axial direction of the cap 17. As a result, when the conical spring 45 elastically returns to its original position while the engaged piece 39 and the engaging portion 41 are engaged with each other, the outer surface 30 of the cap 17 becomes flush with the surface of the mounting material 21.

[0049] The bolt cap 11 is structured so that when the opening edge of the cap 17 abuts against the counterbore surface 25 and the cap 17 is rotated, the latched piece 39 and the latching portion 41 latch together. If a slight clearance is provided between the latching surfaces of the latched piece 39 and the latching portion 41 to improve operability, the height of the cap 17 may be slightly reduced by the amount of that clearance. In this case, when the cap 17 is completely attached, the elastic force of the conical spring 45 pushes the cap 17 back, and with the latching surfaces pressed together, the outer surface 30 of the cap 17 becomes flush with the surface of the mounting material 21.

[0050] In this way, with bolt cap 11, cap 17 can be housed flush with mounting material 21, which aligns the direction of cap 17 and makes bolt 13 less noticeable, further enhancing the design. Furthermore, because cap 17 is housed flush with mounting material 21, it is possible to prevent tampering by removing cap 17. Furthermore, by rotating bolt cap jig 33, the elastic restoring force of conical spring 45 can cause cap 17 to pop out of the counterbore, so even if cap 17 is embedded in the counterbore so that it is flush with mounting material 21, it can be easily removed, which means that dismantling furniture is less complicated.

[0051] In the bolt cap jig 33 according to this embodiment, the jig body 69 has an operation protrusion 67. The bolt cap jig 33 is grasped with fingers on both sides in the thickness direction, and the operation end surface on the short side faces the outer surface 30 of the cap 17. This operation end surface is provided with the above-mentioned operation protrusion 67 that fits into the jig insertion recess 31 provided in the outer surface 30 of the cap 17.

[0052] Here, the jig insertion recess 31 can be recessed in various shapes and numbers. The jig insertion recess 31 is configured such that, when the operation protrusion 67 of the jig body 69 is fitted therein, relative rotation with respect to the jig body 69 is restricted, and the cap 17 is rotatable about its axis.

[0053] The bolt cap jig 33 having such a configuration can rotate the cap 17 by inserting the operating protrusion 67 into the jig insertion recess 31 of the cap 17, and can release the locking portion 41 of the cap 17 from the locking piece 39 of the washer 19 by accessing only from the surface of the mounting material 21.

[0054] Therefore, with the bolt cap 11 of this embodiment, even if the bolt 13 is tightened (assembly completed) in any rotation direction, the rotation direction of the cap 17 covering the head 15 of the bolt 13 can be set to the desired position, so that, particularly when multiple bolts 13 are used, the design direction of each cap 17 of each bolt 13 can be aligned, thereby improving the design when used in furniture, for example.

[0055] Furthermore, with the bolt cap jig 33 according to this embodiment, the cap 17 can be rotated by inserting the operating protrusion 67 into the jig insertion recess 31 of the cap 17, thereby releasing the locking portion 41 of the cap 17 from the locked piece 39 of the washer 19 and removing the cap 17. Because the bolt cap jig 33 can be accessed only from the surface of the mounting material 21, a cap attachment / detachment structure can be achieved in which the cap 17 is accommodated flush with the surface of the mounting material 21. [Explanation of symbols]

[0056] 11...Bolt cap 13...Bolt 14...Shaft 15...Head 17...Cap 19...Washer 21...Mounting material 25...Counterbore surface 27...Bolt through hole 29…Bottom plate part 30...Outward direction 31...Jig insertion recess 33...Bolt cap jig 35...Bolt hole 39…Locked piece 41...Latching part 45...conical spring 47...Rotation restriction protrusion 67...Operation convex part 69...Jig body

Claims

1. A bolt cap having a cap that covers a head of a bolt and a washer that is passed through a shank of the bolt, The cap is The head is formed into a cylindrical shape with a bottom that covers the head with an inner space, and a pair of locking portions that protrude radially inward are formed at equal intervals in the circumferential direction on the inner periphery of the opening edge, and a conical spring is coaxially attached to the inner surface of the bottom plate portion, A jig insertion recess is formed on the outer surface of the bottom plate portion, The washer is The shaft portion is formed in an annular shape having a bolt hole through which the shaft portion is inserted, A plurality of rotation restricting protrusions are formed in the circumferential direction on the underside of the washer facing the seating surface, A bolt cap characterized in that a pair of engaging pieces are formed at equal intervals in the circumferential direction, protruding outward from the outer peripheral edge and sandwiching the engaging portion between the seat surface.

2. the seating surface is a counterbore surface that is coaxial with the bolt through-hole of the mounting material and has an inner diameter that is substantially the same as the outer diameter of the cap, A bolt cap characterized in that the depth of the countersunk surface is approximately the same as the height of the cap in the axial direction.

3. 3. The bolt cap jig for rotating the cap according to claim 1 or 2, A bolt cap jig characterized in that an operating convex portion that fits into the jig insertion recess and can rotate the cap around the cylindrical axis is provided on the jig body that is held by hand.

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