Bolt head cap

Abstract

To enable a bolt head to be covered easily without fail and prevent occurrence of rust starting with another part in the bolt head.SOLUTION: A bolt head cap 11 covers a bolt head 52 in a fastened bolt 51, has a skirt part 12 which contacts with a fastened object 53 at a lower end part, and is made of rubber or synthetic resin. The skirt part 12 is formed so as to be larger than a diameter of the bolt head 52, and a discrimination part 19, which discriminates the inner periphery side of the discrimination part 19 from the outer periphery side, is formed at an inner periphery side portion relative to the skirt part. Further, a magnet 13 is provided at a portion, which faces a top surface 54 of the bolt head 52, on a ceiling surface.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a bolt head cap that covers the head of a fastened bolt to prevent rust. [Background technology]

[0002] One example of a bolt cap that prevents corrosion of the bolt head is the bolt cap described in Patent Document 1 below.

[0003] This bolt cap provides sufficient corrosion resistance by sealing the gap between the bolt head and the cap with resin (caulking material, sealing material). A small hole is formed at the top of the cap so that the resin can spill out when the cap is placed over the bolt head.

[0004] In addition, to prevent the cap from coming off before the resin hardens, the cap has multiple protrusions on its inner periphery. These protrusions are ribbed and extend vertically, making the inner periphery uneven and serving to tighten the bolt head. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2013-19512 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the resin is filled in an amount sufficient to fill the internal space of the cap, and as described above, the filled resin is configured to overflow from the small hole at the top of the cap, so the amount of resin used is very large.

[0007] It would be possible to attach the cap by applying caulking material only to the opening of the cap without providing a small hole, but this is not possible because of the ribs at the opening. Even if there were no ribs, if there was no structure to serve as a reference for applying the caulking material, then excessive application would result.

[0008] Therefore, a main object of the present invention is to reduce the amount of caulking material, etc., required for attaching a cap. [Means for solving the problem]

[0009] The means for achieving this is a bolt head cap made of rubber or synthetic resin which covers the bolt head of a fastened bolt and has a bottom part at its lower end which comes into contact with the object being fastened, the bottom part being formed to be larger than the diameter of the bolt head, and a distinguishing part formed on the inner side of the bottom part to distinguish between the inner side and the outer side thereof.

[0010] In this configuration, the caulking material is applied to the outer periphery of the identification portion before installation. The identification portion identifies the portion to which the caulking material is to be applied, preventing excessive application and ensuring that the amount of caulking material used is appropriate. Effect of the Invention

[0011] According to this invention, the amount of caulking material and the like required for attaching the cap can be reduced. [Brief description of the drawings]

[0012] [Figure 1] Cross-sectional view of the bolt head cap in use. [Diagram 2] Perspective view of steel joint. [Diagram 3] FIG. [Figure 4] One-sided cross-sectional view of the bolt head cap and a front view of the bolt head. [Diagram 5] FIG. 4 is a cross-sectional view showing a use mode of the bolt head cap. [Figure 6] Cross-sectional view of the bolt head caps stacked together. [Figure 7] FIG. 13 is a half-sectional view of a bolt head cap according to another embodiment of the present invention; [Figure 8] FIG. 11 is a cross-sectional view of a bolt head cap according to another example. [Figure 9] FIG. 9 is a cross-sectional view showing a manufacturing die for the bolt head cap of FIG. 8 . [Figure 10] FIG. 9 is a cross-sectional view showing a state in which the bolt head cap of FIG. 8 is used. [Figure 11] FIG. 11 is a cross-sectional view of a bolt head cap according to another example. [Figure 12] FIG. 13 is a perspective view of a bolt head cap according to another example. [Figure 13] FIG. 11 is a plan view of a bolt head cap according to another example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] An embodiment of the present invention will be described below with reference to the drawings.

[0014] Figure 1 shows a cross-sectional view of a bolt head cap 11 in use. This bolt head cap 11 is made of rubber or synthetic resin and covers the bolt head 52 of a fastened bolt 51, has a bottom part 12 at the lower end that comes into contact with a fastened object 53, and is particularly suitable for torsion-type high-strength bolts.

[0015] Torsion type high strength bolts are used for joints in steel frames as shown in FIG. 2, and the bolt head 52 does not always face upward as shown in FIG. 1, but may face sideways or downward.

[0016] When fixing the bolt head cap 11, a caulking material is used to bond the bolt head cap 11 to the fastened object 53 to create an airtight condition.

[0017] This bolt head cap 11 reduces the amount of caulking material used, and by using a magnet 13 as shown in Figure 1, it eliminates the need to hold the bolt head 52 down by hand until the caulking material hardens when the bolt head is facing sideways or downward.

[0018] The bolt head cap 11 has a hollow structure that is circular in plan view and has a flattened dome shape, as seen in the perspective view of Figure 3, to match the shape of the bolt head 52 of the torsion-type high-strength bolt. In other words, the outer surface 14 of the bolt head cap 11 is formed into a flattened dome-shaped curved surface. The top surface 15 of the bolt head cap 11 is circular and flat in plan view, just like the top surface 54 of the bolt head 52, as shown in Figure 4.

[0019] The area of ​​top surface 15 of bolt head cap 11 is approximately the same as the area of ​​top surface 54 of bolt head 52. The portion of outer surface 14 of bolt head cap 11 extending downward from top surface 15 forms a gentle arc and continues, with some interruptions, to the lower end of bottom hem 12.

[0020] The bolt head cap 11 is formed with a predetermined uniform thickness throughout, except for a top surface 15. A lower end surface 12a of the bottom portion 12 is a horizontal surface forming an annular shape, and is parallel to the top surface.

[0021] The material for the bolt head cap 11 may be any suitable natural rubber, synthetic rubber, or synthetic resin, and among these, any suitable soft synthetic resin such as silicone rubber or EPDM (ethylene propylene diene rubber) is preferably used.

[0022] The above-mentioned magnet 13 is provided on the ceiling surface of the bolt head cap 11, i.e., on the inner surface opposite to the top surface 15, at a location facing the top surface 54 of the bolt head 52. The magnet 13 is a disk-like shape of an appropriate thickness that is thicker than the wall thickness of the bolt head cap 11, and the magnet holder 16 equipped with the magnet protrudes downward from the ceiling surface.

[0023] The magnet holding portion 16 has a cylindrical portion 17 that extends downward and holds the outer peripheral surface of the magnet 13. The cylindrical portion 17 surrounds the entire outer peripheral surface of the magnet 13 to hold the magnet 13 against the ceiling surface, and is formed to a depth equal to or shallower than the thickness of the magnet 13 it holds. The circumferential thickness of the cylindrical portion 17 is set to a thickness that can firmly hold the magnet 13. The magnet holding portion 16 is formed integrally with the bolt head cap 11 from the same rubber or synthetic resin, and the magnet 13 is attached to the magnet holding portion 16 later. The magnet may simply be fitted into the magnet holding portion, or may be fixed with an adhesive or the like.

[0024] Height H1 of the underside of the held magnet 13, i.e., the length between the lower end surface of the magnet 13 and the lower end surface 12a of the base portion 12, corresponds to height H2 of the bolt head 52. In other words, the height of the underside of the covering portion 18 is the same as height H2 of the bolt head 52. The height of the underside of the covering portion 18 may be slightly higher than height H2 of the bolt head 52.

[0025] As described above, the magnet holding portion 16 protrudes downward from the ceiling surface, and the bolt head cap 11, which is formed with a uniform thickness, has a gentle arc below the top surface 15 that continues to the lower end of the bottom part 12. For this reason, a space is formed around the magnet holding portion 16 inside the bolt head cap 11, between it and the covered bolt head 52.

[0026] The diameter D1 of the bottom portion 12 is formed larger than the diameter D2 of the bolt head 52 so that this space is formed up to the outer periphery of the bolt head 52.

[0027] Further, an identification portion 19 is formed at a location on the inner periphery side of the bottom hem 12, for identifying the inner periphery side from the outer periphery side. The identification portion 19 is composed of a step portion 21 that protrudes inward. The step portion 21 is a portion where the gentle arc extending downward from the above-mentioned top surface 15 is interrupted. The cross section of the step portion 21 is L-shaped. In other words, the outer surface of the step portion 21 has a vertical surface 21a facing in the outer periphery direction and a horizontal surface 21b facing upward.

[0028] The step portion 21 having such a shape is formed in an annular shape around the entire circumference of the bolt head cap 11.

[0029] In addition, since the step portion 21 has the above-mentioned shape, the portion of the outer surface corresponding to the step portion 21 is recessed inward, and a recess 22 having the above-mentioned vertical surface 21a and horizontal surface 21b is formed all around the circumference. The size of the recess 22 is preferably large enough to allow a fingertip to be hooked thereon.

[0030] Here, the vertically extending inner circumferential surface position (inner diameter D3) of step portion 21 is set to be larger than the outer circumferential edge (diameter D2) of bolt head 52. Specifically, while bolt head 52 of an M22 torsion-type high-strength bolt has a height (H2) of 21 mm and a diameter (D2) of 38.5 mm, the inner diameter D3 of step portion 21 is set to approximately 48 mm, and the outer diameter D1 of bottom portion 12 is set to approximately 64.8 mm.

[0031] The portion below (toward the outer periphery) of step 21 is the portion to which caulking material 61 (see FIG. 5) is applied, and distance L between the lower end surface of step 21 and lower end surface 12a of skirt 12 is set as follows: That is, distance L is set to be smaller than the thickness of extruded caulking material 61 so that when caulking material 61 is extruded and applied once to the lower end surface of step 21, caulking material 61 protrudes above lower end surface 12a of skirt 12 (see the lower diagram in FIG. 5).

[0032] It is preferable to align the polarity of magnets 13 when holding magnets 13 in magnet holding portion 16. If the polarity of magnets 13 is aligned, then when multiple bolt head caps 11 are stacked, they will be attracted to each other by magnetic force, as shown in Figure 6, allowing them to be stacked in a space-saving manner without waste.

[0033] The bolt head cap 11 constructed as described above is used to cover the bolt head 52. Regardless of the orientation of the bolt head 52, as shown in the lower drawing of Figure 5, the bolt head cap 11 is turned upside down with the inner surface facing up, and the caulking material 61 is extruded from the stepped portion 21 to the outer peripheral portion and applied to the entire circumference. At this time, the upper surface of the caulking material 61 is raised higher than the lower end surface 12a of the skirt portion 12. Caulking material 61 is also applied to the exposed lower end surface of the magnet 13. This application may be carried out in an amount sufficient to cover the center of the lower end surface of the magnet 13 so that it extends wider than the lower end surface of the magnet 13 when compressed.

[0034] Next, the magnet holder 16 of the bolt head cap 11 is attracted to the top surface 54 of the bolt head 52. Then, even when the bolt head cap 11 is facing downward as in Figure 5, it comes to cover the bolt head 52, and the caulking material 61 at the bottom 12 is compressed and protrudes beyond the outer periphery of the bottom 12 and then spreads to the inner periphery. This fills the gap between the bottom 12 and the bolt head 52, creating an airtight state.

[0035] Also, the caulking material 61 on the lower end surface of magnet 13 is compressed and spreads between bolt head 52, and is interposed between magnet 13 and bolt head 52, preventing contact between magnet 13 and bolt head 52. In other words, the caulking material 61 on the lower end surface of magnet 13 covers and blocks the entire lower end surface of magnet 13, preventing direct contact with bolt head 52.

[0036] As shown in FIG. 1, the caulking material 61 between the magnet 13 and the bolt head 52 may be omitted.

[0037] The magnet 13 of the bolt head cap 11 maintains its covering state on the bolt head 52 by its magnetic force, so even if you remove your hand before the caulking material 61 hardens, the bolt head cap 11 will not come off or shift position, and the desired covering state can be obtained. This allows for good workability and reliable covering.

[0038] In addition, in the configuration of Patent Document 1, in the case of a round bolt head 52 such as a torsion-type high-strength bolt, the projection only makes contact with the bolt head at a small portion of its lower part, making it difficult to obtain sufficient tightening force. In this regard, the bolt head cap 11 maintains its attachment to the bolt head 52 by magnetic force, so it can be securely attached to a round bolt head 52.

[0039] Moreover, an identification portion 19 is formed on the inner periphery of the bottom hem 12, which serves as a reference for the amount of caulking material 61 to be applied. This allows for less caulking material to be used than if the entire inside of the bolt head cap 11 were filled with caulking material 61, and reduces the weight. This also allows for the desired coating state to be achieved.

[0040] In addition, the lower end surface of magnet 13 is covered with caulking material 61, and magnet 13 is entirely concealed. Therefore, even if magnet 13 rusts, the rust will not transfer to bolt head 52, and the desired fastening force can be exerted for a long period of time.

[0041] As for the caulking material 61 applied to the bottom end surface of magnet 13, the exposed bottom end surface of magnet 13 represents a certain closed area, and thus serves as a clear reference / mark for applying caulking material 61, similar to the above-mentioned bottom part 12. For this reason, if the entire magnet 13 is exposed and there is no reference for applying the caulking material, applying the caulking material would hinder the magnetic attraction of the magnet, but this does not cause such inconvenience, and the magnetic attraction can be ensured while concealing magnet 13.

[0042] Furthermore, the aforementioned identification portion 19 is composed of a step portion 21, and a recess 22 is formed on the outer surface 14, so that the recess 22 serves as a hook for the fingertip when fixing the bolt head cap 11, improving workability.

[0043] Moreover, the identification portion 19 formed by the step portion 21 serves as a receiver for the adhering caulking material 61 and prevents it from flowing away, so that sufficient sealing performance can be ensured even when the product is mounted upside down.

[0044] Furthermore, outer surface 14 is formed as a curved surface in the shape of a flattened dome, and magnet holding portion 16 protrudes downward from the ceiling surface and does not protrude beyond top surface 15. Therefore, when bolt head cap 11 is attached, it is possible to prevent bolt head cap 11 from accidentally colliding with another object and being subjected to an impact, resulting in it coming off.

[0045] Another example will be described below. In this description, the same components as those in the above-described configuration will be given the same reference numerals and detailed description thereof will be omitted.

[0046] 7 shows an example in which magnet holder 16 is provided with covering 18. The covering is a rubber or synthetic resin part formed on the surface of magnet 13, i.e., the bottom end face, and is interposed between bolt head 52 to prevent contact between magnet 13 and the surface of bolt head 52.

[0047] Covering portion 18 covers the entire surface of magnet 13, so that the magnet is entirely covered with rubber or synthetic resin. The entire bolt head cap 11 including magnet holding portion 16 can be formed by so-called insert molding or two-color molding.

[0048] The thickness t of the covering portion 18 is set to, for example, about 0.5 mm to 1 mm, preferably up to 1.2 mm. The height of the lower surface of the covering portion 18 corresponds to the height of the bolt head 52.

[0049] FIG. 8 shows an example in which covering portion 18 of magnet holder 16 does not cover the entire surface of magnet 13, leaving part of magnet 13 exposed.

[0050] That is, the covering portion 18 is formed on a closed portion of the surface of the magnet 13, specifically, on a portion other than the portion corresponding to the center of the surface of the magnet 13.

[0051] In this example, magnet 13 is annular rather than disk-shaped, with through hole 13a formed in the center. Magnet 13 of this shape is entirely covered with magnet holder 16 except for the edge of through hole 13a.

[0052] The bolt head cap 11 having such a structure is manufactured by insert molding in a mold as shown in Fig. 9. That is, a stepped pin 72 is erected in the part of lower mold 71 that holds magnet 13, and magnet 13 is held floating. When molding material is injected while upper mold 73 presses the tip of pin 72 and the periphery of through hole 13a of magnet 13, the bolt head cap 11 having the structure described above is obtained.

[0053] Thus, the bolt head cap 11 having the coating 18 but with a portion of the magnet 13 exposed may be used as shown in FIG.

[0054] That is, caulking material 61 is applied to the outer periphery of step 21 of bolt head cap 11 and to the missing portion in the center of coating 18, i.e., the portion where through hole 13a of magnet 13 is exposed. Then, magnet holder 16 is brought into contact with top surface 54 of bolt head 52 as shown by the arrow. Magnet 13 is attracted to top surface 54 of bolt head 52, and the crushed caulking material 61 deforms and fills in the missing portion of coating 18, with the excess flowing into through hole 13a of magnet 13. Caulking material 61 at hem 12 is pressed against fastened object 53, sealing and bonding the lower end surface 12a of hem 12 and its inner portion.

[0055] Although part of the magnet 13 is exposed, unlike conventional cases where the entire magnet is exposed, the exposed part is on the inside and is only a part, so it serves as a clear reference / marker for applying the caulking material 61. For this reason, if the entire magnet 13 is exposed and there is no reference for applying the caulking material, applying the caulking material would hinder the magnetic attraction force, but this does not cause any inconvenience, and the magnetic attraction force can be reliably applied while the magnet 13 is concealed.

[0056] Figure 11 is a cross-sectional view of another example of the bolt head cap 11. The bolt head cap 11 in Figure 11(a) is formed in such a manner that the missing portion of the bolt head cap 11 shown in Figure 8, i.e., the through hole 13a of the magnet 13 and the surrounding area thereof, are filled in advance with rubber or synthetic resin. In the figure, 23 denotes the filled portion.

[0057] FIG. 11(b) shows an example in which the lower end surface 12a of the skirt portion 12 is formed in a fin shape that is thinner and more easily deformed toward the outer periphery.

[0058] 11(c) shows an example in which a depending rib 24 is formed on step portion 21. Depending on the entire periphery, depending rib 24 regulates the position of the inner periphery of the caulking material when the caulking material is applied.

[0059] 12 is a perspective view of another example of a bolt head cap 11, in which vertically extending ribs 25 are formed at predetermined intervals on the bottom portion 12 of the outer surface 14. These ribs 25 are portions that provide a hook for the fingertips when the bolt head cap 11 is attached, and improve the workability when pressing the bolt head cap 11 against the object 53 to be fastened.

[0060] 13 is a plan view of another example of a bolt head cap 11, and as shown in this figure, a plurality of bolt head caps 11 are connected via flexible or pliable connecting parts 26. The connecting parts 26 are made of the same material as the bolt head caps 11, are string-like, and have a plurality of curved parts 26a that are semicircular in shape when viewed from above. The shape and length of the connecting parts 26 and the number of bolt head caps 11 to be connected are set appropriately.

[0061] The bolt head caps 11 connected by the connecting portion 26 in this manner are such that even if one bolt head cap 11 accidentally falls off the bolt head, the other bolt head caps 11 will prevent it from falling off.

[0062] In addition, the step portion 21 and the recessed portion 22 may be formed annularly over the entire circumferential direction, or may be formed intermittently.

[0063] Furthermore, the identification portion 19 may be any other marking other than the step portion 21 as described above, and may be formed, for example, by an engraving or a embossment (rib). [Explanation of symbols]

[0064] 11...Bolt head cap 12...Hem 13...Magnet 14...Outer surface 18…Covering part 19…Identification section 21...Step 22…Recess 51…Bolt 52…Bolt head 53...Object to be fastened 54…Top surface

Claims

1. A bolt head cap made of rubber or synthetic resin covers the bolt head of a fastened bolt and has a bottom part at the bottom end that comes into contact with the object to be fastened. The bottom portion is formed to be larger than the diameter of the bolt head, An identification portion is formed at a portion on the inner periphery side of the bottom portion to distinguish between the inner periphery side and the outer periphery side of the bottom portion, The identification portion is formed of a step portion protruding inward, An inwardly recessed portion is formed at a portion of the outer surface corresponding to the step portion. Bolt head cap.

2. A magnet is provided on the ceiling surface at a position facing the top surface of the bolt head.

2. The bolt head cap of claim 1.

3. A coating portion made of rubber or synthetic resin is formed on the surface of the magnet and is interposed between the magnet and the bolt head to prevent contact between the magnet and the top surface of the bolt head.

3. A bolt head cap as claimed in claim 2.

4. The outer surface is formed of a flattened dome-shaped curved surface, The portion having the magnet protrudes downward from the ceiling surface. A bolt head cap according to claim 2 or 3.

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