JPH0231016A - Prevention of bolt and nut from corrosion - Google Patents

Abstract

PURPOSE:To facilitate the removal of a cap by covering a projection of a structure with the cap having a cut-open portion, pouring anticorrosive into the cap, and cutting open the cut-open portion after setting the anticorrosive to remove the cap. CONSTITUTION:Projections of a bolt 2 and nut 4 are covered with caps 14, 16 having cut-out portions 18, 19 as cut-open portions applied with tapes 24, 25 respectively. Anticorrosive is poured from orifices 15, 17 into the caps 15, 16 and set. Thereafter, the cut-open portions are cut open to remove the caps 14, 16. In the removal of the caps 14, 16 a large force is thus not needed so that the caps 14, 16 can be easily removed.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for preventing corrosion of bolts and nuts.

[Prior art and problems to be solved by the invention] Conventionally,
2. Description of the Related Art When constructing various structures such as concrete structures and steel structures, bolts and nuts are widely used to connect members.

Therefore, particularly in the case of outdoor structures, the bolts and nuts are exposed to the outside air, and if left as is, corrosion will progress over a long period of time, causing a problem in that the predetermined bonding strength will be lost. For this reason, in order to prevent corrosion of bolts and nuts, it has been conventional practice to apply an anticorrosive coating to the exposed parts.

However, since the bolt number nut has a complicated shape, the coating work efficiency is not good, and the coating thickness tends to be particularly thin at the corners, resulting in a decrease in anticorrosion performance. Furthermore, since it is difficult to form such a thick coating film with painting, long-term corrosion protection cannot be expected.

Therefore, in order to apply a thick anti-corrosion layer to the protruding parts of bolts and nuts, a cap with a shape corresponding to the protruding parts of the bolts and nuts is prepared, and after storing the anti-corrosive material in the cap, the cap is attached to the bolts and nuts. A method has been proposed in which the cap is placed over the nut protrusion, the anticorrosive material is hardened in this state, and the cap is left attached as is.

However, in this method, since the cap is left attached as is, there is a risk that the cap may fall off after a long period of time due to shrinkage of the corrosion protection or vibrations transmitted from the structure. In particular, structures related to transportation (e.g. railways, subways,
In the case of structures attached to roads, vibrations are noticeable and falling can pose a danger to traffic.

Furthermore, this method has the disadvantage that if the cap is made of plastic, it is easily flammable and dangerous in the event of a fire, and if the cap is made of metal, it must be coated with anti-corrosion coating.

Furthermore, in this method, since the cap is placed over the protrusion of the bolt or nut with the anti-corrosion coating contained in the cap in advance, voids may be created within the cap, making it impossible to form a good anti-corrosion coating. In order to prevent the occurrence of such voids,
It is inevitable that an excessive amount of corrosion protection material will be used, and the corrosion protection material will sag, resulting in a poor appearance and a large amount of corrosion protection material being wasted.

Therefore, in view of the problems of the prior art as described above, the present applicant has proposed a method that has high working efficiency and is capable of forming a sufficiently thick anti-corrosion coating, but which does not allow the formation of voids in the anti-corrosion coating, resulting in a decrease in anti-corrosion performance. As a corrosion prevention method, there is a process in which a bolt and/or nut connected to a structure protrudes from the structure with a transparent or translucent cap that covers the protrusion; a step of injecting corrosion protection into the cap through an injection port provided in the cap and discharging excess corrosion protection from an outlet provided in the cap; a step of hardening the corrosion protection filled in the cap; and a step of curing the corrosion protection filled in the cap. A method for preventing corrosion of bolts and nuts has already been proposed (Japanese Patent Application No. 109160/1983), which is characterized by comprising the step of subsequently removing the cap.

However, in the method according to this proposal, a step of removing the cap is performed, but in the step of removing the cap, it is necessary to apply a considerably large force depending on the type of corrosion protection material. This is because it is difficult for air to enter between the cap and the hardened anti-corrosion material, resulting in a high adhesion force due to atmospheric pressure. This high adhesion occurs in the same way even when a mold release agent for anti-corrosion is applied to the inner surface of the cap.

In view of the above-mentioned technical background, the present invention provides a method that enables the formation of a sufficiently thick anti-corrosion coating with high working efficiency, and does not cause voids to occur in the anti-corrosion coating and cause a decrease in anti-corrosion performance. In addition, another object of the present invention is to provide an improved method for preventing corrosion of bolts and nuts, which does not require a large amount of force during operation, that is, allows easy removal of the cap.

[Means for Solving the Problems] According to the present invention, the above object is to provide a transparent or semi-transparent covering for the protrusion of a bolt and/or nut connected to a structure from the structure. a step of covering with a transparent cap, a step of injecting anticorrosion into the cap from an injection port provided in the cap,
a step of hardening the anticorrosive material filled in the cap; and a step of removing the cap while cutting a cuttable part provided on the side of the cap along the direction of the bolt from the edge after the hardening; Provided is a method for preventing corrosion of bolts and nuts, the method comprising:

Further, according to the present invention, the transparent or translucent material used in the above-mentioned method of the present invention has an anti-corrosion inlet, an anti-corrosive discharge port, and a cuttable part provided on the side (extending to the scraped edge). A cap is provided.

[Example] Hereinafter, specific examples of the present invention will be described with reference to the drawings.

FIGS. 1(a) to 1(g) are schematic process diagrams showing a first embodiment of the method of the present invention.

In these figures, 2 is a bolt, 4 is a nut, and 6 and 8 are concrete plates that are structural members connected by these bolts and nuts. 10 is a washer placed between the head of the bolt 2 and the concrete plate 6 during this connection, and 12 is a washer placed between the nut 4 and the concrete plate 8 during the above connection. Reference numeral 14 designates a cap for the protrusion on the bolt head side used in carrying out the method of the present invention, and reference numeral 16 indicates a cap for the protrusion on the bolt/nut fitting side used in carrying out the method of the present invention. The cap 14.16 is a transparent or semi-transparent body having a shape that can cover the bolt head side protrusion or the bolt neck side protrusion from the side and top at an appropriate distance (for example, 2 mm). Consisting of The above cap 14
has small through holes 15,15' on the lower and upper sides, the diameter of which is, for example, 2 to 4 mm. A notch 18 is formed on the side of the cap 14 extending almost the entire length from the lower edge in the vertical direction.
is formed. A tape 24 is pasted and joined to the cut portion from the inside of the cap, and the tape extends from the lower edge of the cap 14 to the outside.

The tape preferably has high tensile strength; for example, an adhesive tape containing reinforcing fibers along the length can be used. Further, the cap 16 has small through holes 17 and 17' on the lower side and the upper side, and the diameter of the small holes is, for example, 2 to 4.
It is mm. A notch 19 is formed in the side of the cap 16 in the vertical direction from the upper edge.

Then, tape 25 is applied to the notch from the inside of the cap.
is applied and bonded, and the tape extends outward from the upper edge of the cap 16. As the tape,
An adhesive tape similar to the tape 24 described above can be used. Regarding the cap 14 for the bolt head protrusion,
If the depth is shallow, the cap can be removed with a light force, so there is no need to make a cut in the cap or use tape.

The transparent cap 14.16 has a thickness of, for example, 0.5 m.
m polypropylene.

First, as shown in FIG. 1(a), bolt 2, nut 4. The concrete plates 6 and 8 are joined by washers 10 and 12, and a cap 14 for the bolt head side protrusion and a cap 16 for the bolt/nut fitting side protrusion are prepared.

Next, as shown in FIG. 1(b), cover the port head side protrusion with the cap 14 from above.

The cap 16 is placed on the bolt/nut fitting side protrusion from below.

Next, as shown in FIG. 1(e), the anticorrosive injection nozzle (for example, the nozzle of an airless injection gun) 20 is aligned with the small hole 15 on the lower side of the cap 14, and from this point the cap 14 and the port are connected. Corrosion-proofing material 22 is injected into the space formed by the head side protrusion and the concrete plate 6. Similarly, as shown in FIG. 1(C), the anti-corrosion injection nozzle 20 is fitted to the small hole 17 on the lower side of the cap 16, and from there the anti-corrosion injection nozzle 20 is connected to the cap 16, the bolt/nut fitting side protrusion and the concrete. The anticorrosive material 22 is injected into the space formed by the plate 8.

As the corrosion protection material 22, conventionally used materials such as epoxy resin-amide sealants, polyisocyanate-polyol sealants, non-drying oil sealants, etc. can be used. In addition, in order to prevent it from falling off due to external forces such as vibrations after curing and to make it flame retardant, organic-inorganic or Inorganic anticorrosive materials are preferred, and the following formulations are suitable as such materials.

(1) (a) Acrylic emulsion resin and/or (b) epoxy emulsion resin; Aliphatic polyamine curing agent: 5 to 50 parts by weight (solid content equivalent); (2) Cement: -20 to 70 parts by weight. , etc.)... 5 to 40 parts by weight of an anticorrosion composition having a viscosity of 20 to 1000 voids, which is prepared by adding water to the composition, which further contains anticorrosive pigments, extender pigments, additives, etc. as required.

The injected anticorrosion 22 gradually moves from the lower side of the space to the upper side and fills the space. In addition, the anticorrosion 22 is injected from the small hole 15' on the upper side of the cap 14, contrary to the above.
Alternatively, it may be performed through the small hole 17' on the upper side of the cap 16.

Since the caps 14 and 16 are transparent or semi-transparent when injecting the above-mentioned anticorrosion, the state of the injection can be visually observed, and it is possible to check for any remaining in the void, and take appropriate measures.

In this way, as shown in FIG. 1(d), a corrosion-proof filling state without remaining voids can be obtained. Leave in this state to allow the anticorrosion to harden naturally.

FIG. 1(e) shows an external view of the state shown in FIG. 1(d).

Next, after the anticorrosive hardening, as shown in Fig. 1(f),
By manually pulling the tip of the tape 24 extending from inside the cap 14 to the outside, the notch 18 in the cap is cut out from below. Thereby, sufficient air is supplied between the cap and the anticorrosive material 22. Similarly, by manually pulling the tip of the tape 25 extending from inside the cap 16 to the outside, the notch 19 in the cap is incised from above. Thereby, sufficient air is supplied between the cap and the anticorrosive material 22.

When the cap 14.16 is removed with the notch in the cap 14.16 opened as described above, the cap can be easily removed with a small force, and the anticorrosive material 22 is removed as shown in FIG. 1(g).
A form with a desired film thickness is obtained.

To reuse the caps 14, 16, the incisions 18, 19 can be repaired by joining each with tape 24, 25.

FIGS. 2(a) and 2(b) are explanatory diagrams of a second embodiment of the method of the present invention, and correspond to FIGS. 1(e) and (f), respectively. In FIG. 2, the same members as in FIG. 1 are given the same reference numerals.

In this example, the notch 18.19 of the cap 14.16 is
extend over the entire cap, dividing the cap, and connect these cuts from the outside of the cap with tape 26.2.
It is joined by pasting 7. As shown in FIG. 2(b), the tape can be manually pulled to release the bond and cut out the notches 18, 19 in the cap. Thereby, sufficient air is supplied between the cap 14, 16 and the anticorrosive material 22.

In order to reuse the caps 14 and 16, they can be repaired by joining the notches 18 and 19 with tape 26 and 27. As mentioned above, the depth of the cap 14 for the bolt head protrusion is If the cut is shallow, it is not necessary to make a cut in the cap and use no tape.

FIGS. 3(a) and 3(b) are explanatory diagrams of a third embodiment of the method of the present invention, and correspond to FIGS. 1(e) and (f), respectively. In FIG. 3, the same members as in FIG. 1 are given the same reference numerals.

In this embodiment, in place of the notches 18 and 19 of the first embodiment, a pair of recesses and depressions (for example, fasteners) 28 and 29 are formed on the caps 14 and 16 so that they can be held together. As shown in FIG. 3(b), the fastener can be manually disengaged and cut open. Thereby, sufficient air is supplied between the cap 14, 16 and the anticorrosive material 22.

To reuse the cap 14.16, remove the fastener 28.
．． 29 and repair it.

FIGS. 4(a) and 4(b) are explanatory diagrams of a fourth embodiment of the method of the present invention, and correspond to the above-mentioned FIGS. 1(e) and (f), respectively. In FIG. 4, the same members as in FIG. 1 are given the same reference numerals.

In this embodiment, the cap 14.16 has a pair of perforations at positions corresponding to the notches 18, 19 in the first embodiment described above, and tongue pieces 30, 3 are provided as incision parts.
1 was formed.

As shown in FIG. 4(b), by pulling the tongue piece with one hand, the perforation can be broken and the incision can be made. Thereby, sufficient air is supplied between the cap 14, 16 and the anticorrosive material 22.

In order to facilitate the removal of the cap after the anticorrosion hardening and incision of the incisable portion, it is preferable to apply an appropriate mold release agent such as grease to the inner surface of the cap in advance.

[Effects of the Invention] According to the present invention as described above, 4 work efficiency is high, it is possible to form a sufficiently thick anti-corrosion coating, and there is no possibility that voids are generated in the anti-corrosion coating and the anti-corrosion performance is deteriorated. In particular, a corrosion prevention method is provided that does not require a large amount of force during operation because the usable part is incised when the cap is removed.

In addition, when injecting anticorrosive materials, the injection status can be visually observed because the cap is transparent or translucent.

You can check for any remaining space in the void.

Further, since the gap is removed after the anti-corrosive hardening, there is no problem of the cap falling or combustion in the event of a fire, and the cap can be used repeatedly and costs can be reduced.

[Brief explanation of the drawing]

FIGS. 1(a) to 1(g) are schematic process diagrams showing an example of the method of the present invention. Figure 2 (a), (b), Figure 3 (a), (b
) and FIGS. 4(a) and 4(b) are explanatory diagrams of an embodiment of the method of the present invention. 2: Bolt, 4: Nut, 6.8: Concrete plate, 10.12: Washer, 14.16: Cap, 15.15', 17.17': Small hole, 18.19: Notch, 20: Corrosion protection Injection nozzle, 22: Anti-corrosion, 24, 25, 26, 27: Tape, 28, 2
9: Fastener 30.31: Tongue piece. Figure 1 (a) Figure 1 (b) Figure (C) Figure ((f) Figure CO) Figure (b) Figure (e) Figure (G) Figure (b)

Claims (2)

[Claims] (1) The process of covering the protruding part of the bolt and/or nut connected to the structure with a transparent or semi-transparent cap that covers the protruding part, and the step of covering the protruding part of the bolt and/or nut connected to the structure, and the step of covering the protruding part with a transparent or semi-transparent cap, and the process of applying a transparent or translucent cap to cover the protruding part of the bolt and/or nut connected to the structure. A step of injecting a corrosion-proofing material into the cap, a step of hardening the corrosion-proofing material filled in the cap, and a cuttable part provided on the side of the cap along the direction of the bolt from the edge after the hardening. A method for preventing corrosion of bolts and nuts, comprising the step of removing the cap while making an incision. (2) A transparent or semi-transparent material having a corrosion-proofing inlet, a corrosion-proofing outlet, and a cuttable part provided on the side and extending to the edge, which is used in the method for preventing corrosion of bolts and nuts according to claim 1. cap.