JP2010116976A - Bolt rust prevention method and rust prevention cap for bolts used for the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To cancel the possibility that airtightness inside rust prevention cap may be influenced by a temperature change. <P>SOLUTION: A body section 21 covering the shank 5a of bolt 5 which is temporarily fixed to a bolt hole 3 of bottom steel plate 1 through a bolt temporarily fixing nut 14 is provided, moreover a thread section 23 screwed into the shank 5a of the bolt 5 is provided inside the body section 21 in a rust prevention cap 20 for bolt with an opening 22 attached in caulking to a cap attaching section 17 of the bolt temporarily fixing nut 14. Furthermore, the possibility that airtightness between the opening 22 and the cap attaching section 17 of the bolt temporarily fixing nut 14 may be influenced by an inner atmospheric pressure of the rust prevention cap 20 for bolt is canceled by compulsorily caulking the opening 22 to the cap attaching section 17 of the bolt temporarily fixing nut 14 by utilizing a tightening axial force with respect to the bolt 5 of the thread section 23 of the rust prevention cap 20 for bolt. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is a bolt that is arranged so as to cover a shaft portion of a bolt in a state where a bolt for fastening an overlapping portion of steel plates is temporarily fixed to a bolt hole of one steel plate in advance using a bolt temporary fixing nut. A bolt rust prevention method for preventing rusting of the bolt in advance by bringing the opening of the rust prevention cap into close contact with the cap mounting portion provided on the bolt temporary fixing nut, and a bolt rust prevention cap used in the method It is about.

  In recent years, as a floor slab for constituting a bridge, the formwork forming the lower surface of the concrete layer of the floor slab is used as a panel-shaped bottom steel plate, and concrete is directly placed inside the bottom steel plate, thereby Synthetic floor slabs of the type in which steel plates and concrete layers are joined together have come to be used.

  In order to construct this type of composite floor slab, first, after arranging the bottom steel plates in the radial direction on the main girder, it is necessary to connect the adjacent bottom steel plates.

  When connecting the adjacent bottom steel plates, usually, as shown in FIG. 3, the bottom steel plates are arranged in a state in which the contact plate 2 is placed on the upper side of the butt ends of the adjacent bottom steel plates 1. Bolts (high-strength bolts) 5 are inserted from the lower surface side of the bottom steel plate 1 into the bolt holes 3 and 4 drilled in the overlapping portion of 1 and the attachment plate 2. After that, the washer 7 is fitted to the tip of the bolt 5 protruding above the attachment plate 2 and then the nut 6 is screwed and tightened so that each of the bottoms as the overlapping portion of the steel plates is secured. The overlapping portions of the steel plate 1 and the attachment plate 2 are joined by bolts 5 so that the butt ends of the adjacent bottom steel plates 1 are connected to each other via the attachment plate 2.

  When the overlapping portion of the bottom steel plate 1 and the attachment plate 2 is joined using the bolt 5 as described above, the bolt 5 inserted through the bolt holes 3 and 4 from the lower surface side of the bottom steel plate 1 is dropped. It was necessary to screw and tighten the nut 6 from the upper side of the attachment plate 2 while being held so as not to fall.

  Therefore, as a technique for eliminating the work from the lower surface side of the bottom steel plate at the construction site of the bottom steel plate 1 of the composite floor slab, a bolt 5 inserted from below into the bolt hole 3 of the bottom steel plate 1 is used. It has been considered that the bolt hole 3 is held so as not to drop off.

  4 (a), (b), and (c) show a technique using a conventionally proposed hook ring 8 as an example of means for holding the bolt 5 in the bolt hole 3 of the bottom steel plate 1 so as not to drop off. Is.

  The hook ring 8 has a slightly larger outer diameter than the bolt hole 3 formed in the bottom steel plate 1 and has a length dimension (height dimension) in the axial direction of the attachment plate 2. A female screw portion (not shown) for screwing the shaft portion (screw portion) 5a of the bolt 5 is provided on the inner peripheral surface of a ring-shaped member having a dimension smaller than the plate thickness. As a result, as shown in FIG. 4 (a), after the bolts 5 are respectively inserted from below into the bolt holes 3 provided at the butt end portions of the adjacent bottom steel plates 1, the shafts 5a of the respective bolts 5 are inserted into the shaft portions 5a. The hook ring 8 is fitted by screw connection from above, and the hook ring 8 is applied around the bolt hole 3 of each bottom steel plate 1 so that the bolt 5 in the bottom steel plate 1 is bolted in advance. Can be held in a state in which the fall is prevented.

  Therefore, thereafter, as shown in FIG. 4 (b), an attachment plate formed by drilling a bolt hole 4 large enough to allow the hook ring 8 to pass above the butt end of each bottom steel plate 1. 2 is placed from above so that the bolt 5 held in the bolt hole 3 of each bottom steel plate 1 is inserted into the bolt hole 4 from above, and then the bolt 5 as shown in FIG. In addition, by fitting the nut 6 from above through the washer 7 and tightening from above the attachment plate 2, the joining operation of the attachment plate 2 to each bottom steel plate 1, that is, the above-described operation via the attachment plate 2 is performed. The connection work of the bottom steel plates 1 can be performed only from the top side of the bottom steel plate 1 (see, for example, Patent Document 1).

  By the way, the bolt 5 temporarily fixed to the bolt hole 3 of the bottom steel plate 1 as described above includes a step of carrying the bottom steel plate 1 into the construction site after the temporary fixing work, and the bottom steel plate 1 on the main girder. And the step of placing the attachment plate 2 on the upper side of the butted ends of the adjacent bottom steel plates 1, and further, the bolt hole 4 of the attachment plate 2. The position is used to pass the step of correcting the position of each bottom steel plate 1 in which the bolt 5 is temporarily fixed to the bolt hole 3 to join the bottom steel plate 1 and the attachment plate 2 to the bolt 5. Until the nut 6 is fully tightened, it is exposed outdoors.

  Therefore, if there is a period from the temporary fixing operation of the bolt 5 to the bolt hole 3 of the bottom steel plate 1 to the main fastening operation at the site, rust may be generated on the shaft portion of the bolt 5. If rust is generated in the shaft portion 5a, the torque coefficient is disturbed, and there is a concern that the axial force after final tightening becomes unstable.

  Therefore, conventionally, as the bolt 5 temporarily fixed to the bottom steel plate 1 by using a bolt 5 that has been rust-prevented in advance by a primer, from the temporary fixing operation to the bolt hole 3 of the bottom steel plate 1, Until the final tightening operation, the generation of rust in the shaft portion 5a of the bolt 5 was suppressed.

  However, when the bolt 5 that has been rust-prevented in advance is used as the bolt 5 that is temporarily fixed to the bolt hole 3 of the bottom steel plate 1, the number of bolts 5 that are used for the construction of the composite floor slab of the bridge is enormous. As a result, there is a problem that the cost is significantly increased as compared with the case of using a general bolt (high-strength bolt).

  In addition, as shown in FIG. 5, as one of means for performing corrosion prevention (rust prevention) of the shaft portion 11a of the bolt 11 and the nut 12 after being used for joining the two plates 9 and 10. A screw covering portion 13a covering the tip and side surfaces of the shaft portion 11a of the bolt 11, a head covering portion 13b covering the nut 12, a collar covering portion 13c covering the collar 12a of the nut 12, and a plate extending along the plate 9 There has been conventionally proposed a method in which the anticorrosion cap 13 including the covering portion 13d is made of PVC containing zinc powder, and the anticorrosion cap 13 is mounted so as to cover the shaft portion 11a and the nut 12 of the bolt 11 ( For example, see Patent Document 2).

  Therefore, as shown in FIG. 4 (a), as a measure for preventing rust of the shaft portion 5a of the bolt 5 temporarily fixed to the bolt hole 3 of the bottom steel plate 1, the bolt 5 has a structure as shown in FIG. It is conceivable to cover the anti-corrosion cap 13.

  However, the anti-corrosion cap 13 shown in FIG. 5 is not designed to be able to seal between the plate covering portion 13d and the plate 9, and the screw covering portion 13a is connected to the tip of the shaft portion 11a of the bolt 11. Even if it is in a state of covering the side, there is a spiral space along the groove of the screw, and it can be sealed by blocking the contact between the shaft part of the bolt to be anticorrosive and the outside air Therefore, it is difficult to prevent the shaft portion 11a of the bolt 11 from coming into contact with the outside air or water to reliably prevent rusting at the shaft portion 11a.

  Therefore, the present inventor, in the previous application (Japanese Patent Application No. 2007-302596), in order to join the overlapped portion of the two steel plates, the bolt of one of the two steel plates. A rust prevention method and device for a fastening bolt that allows a bolt in a state of being temporarily fixed by being inserted into a hole to be able to prevent contact with outside air and to prevent rusting of a shaft portion of the bolt. is suggesting.

  As shown in FIGS. 6 (a), 6 (b), and 6 (c), the fastening bolt anti-corrosion device is a bottom steel plate 1 of a composite floor slab as two superposed steel plates to be joined using a bolt 5. In the state where the bottom steel plate 1 is screwed with the shaft portion 5a of the bolt 5 inserted through the bolt hole 3 of the bottom steel plate 1 as one steel plate of the attachment plate 2 from the lower surface side as one side surface side. The bolt temporary fixing nut 14 that can be brought into close contact with the end portion on the upper surface side as the other side surface end portion in the bolt hole 3, and the body portion 15a on the one end side in the longitudinal direction as a cylindrical shape with one end portion in the longitudinal direction closed. 5, the opening 15b on the other end in the longitudinal direction is brought into contact with the bolt temporary fixing nut 14 so that the opening 15b and the bolt temporary fixing nut are covered. Anti-rust cap to seal between 14 A configuration equipped with a 15.

  Furthermore, the bolt temporary fixing nut 14 has an outer diameter that is larger than the bolt hole 3 of the bottom steel plate 1 from one end in the axial direction where the outer diameter is smaller than that of the bolt hole 3 provided in the bottom steel plate 1. A taper portion 16 whose outer peripheral surface gradually increases in diameter toward the other end portion in the axial direction as a diameter is provided, and on the other end side in the axial center direction of the taper portion 16, One end in the axial direction of the cylindrical cap mounting portion 17 extending in the axial direction with a required outer diameter smaller than the outer diameter of the other axial end is integrally attached.

  On the inner peripheral surface of the bolt temporary fixing nut 14, a female screw portion 18 is provided for screwing onto the shaft portion 5 a of the bolt 5 used for joining the bottom steel plate 1 and the attachment plate 2.

  The bolt temporary fixing nut 14 is made of, for example, a synthetic resin or a soft metal such as brass, copper, aluminum, etc., compared to the bottom steel plate 1 and the bolt 5 so as to allow required elastic deformation.

  The rust prevention cap 15 is made of a resin having flexibility, and the inner diameter of the opening 15b at the other end in the longitudinal direction is slightly smaller than the outer diameter of the cap mounting portion 17 of the bolt temporary fixing nut 14. Thus, by attaching the opening 15b of the rust prevention cap 15 so as to cover the outer periphery of the cap attachment part 17 of the bolt temporary fixing nut 14, the inner peripheral surface of the opening 15b of the rust prevention cap 15 is attached. And the outer peripheral surface of the cap mounting portion 17 of the temporary bolt fixing nut 14 are in close contact with each other so that the space between the antirust cap 15 and the temporary bolt fixing nut 14 can be sealed.

  Further, the body portion 15 a of the rust prevention cap 15 is set to have an inner diameter slightly smaller than the outer diameter of the shaft portion 5 a of the bolt 5, and the body portion 15 a of the rust prevention cap 15 is changed to the shaft portion 5 a of the bolt 5. If it covers from the front end side, the inner peripheral surface of the body part 15a can be brought into close contact with the outer periphery of the shaft part 5a of the bolt 5 over a long range in the longitudinal direction. A strong holding force for holding the rust preventive cap 15 in a state where the rust preventive cap 15 is attached to the bolt 5 can be exerted by the body portion 15a closely attached to the outer periphery of the shaft portion 5a of the bolt 5.

  Using the bolt temporary fixing nut 14 and the rust prevention cap 15 having the above-described configuration, the bolt 5 used for joining the bottom steel plate 1 and the splicing plate 2 of the composite floor slab as the two laminated steel plates, When rust prevention is performed while temporarily fixed to the bolt hole 3 of the bottom steel plate 1, a bolt (high-strength bolt) is inserted into the bolt hole 3 of the bottom steel plate 1 from below as shown in FIG. 5) For example, after the torcia-type bolt 5 is inserted and arranged, the bolt temporary fixing nut 14 is placed on the shaft portion 5a of the bolt 5 from one end side in the axial direction where the tapered portion 16 is provided. The female screw part 18 is screwed by fitting. Thereafter, by tightening the bolt temporary fixing nut 14 with respect to the bolt 5, the tightening axial force of the bolt temporary fixing nut 14 against the bolt 5 is used to make the tapered portion 16 of the bolt temporary fixing nut 14. Then, from one end portion on the small diameter side, it is screwed into a gap between the upper end portion of the bolt hole 3 of the bottom steel plate 1 and the bolt 5 to be wedged. As a result, a strong tightening axial force can be applied to the bolt 5 by the bolt temporary fixing nut 14, and a large frictional force is generated between the bolt temporary fixing nut 14 and the bolt 5. Further, the bolt temporary fixing nut 14 is, by a strong tightening axial force acting on the bolt 5, to a portion having a larger diameter than a position where the bolt hole 3 of the bottom steel plate 1 originally has the same diameter in the tapered portion 16, By forcibly biting into the gap between the bolt hole 3 and the bolt 5 in a wedge shape, it is compressed and elastically deformed in the gap between the bolt hole 3 and the bolt 5 of the bottom steel plate 1, and the restoring force causes the temporary bolt. Since the outer peripheral surface of the taper portion 16 of the fixing nut 14 is in close contact with the inner peripheral surface of the upper end portion of the bolt hole 3 of the bottom steel plate 1 over the entire circumference in the circumferential direction, the bolt temporary fixing nut 14 and the bottom A large frictional force is also generated between the bolt holes 3 of the steel plate 1. Therefore, the bolt 5 has a large frictional force between the bolt hole 3 and the bolt temporary fixing nut 14 and a large friction between the bolt temporary fixing nut 14 and the bolt 5 in the bolt hole 3 of the bottom steel plate 1. Temporarily fixed in a state where rotation is prevented by force.

  Further, at this time, as described above, the outer peripheral surface of the tapered portion 16 of the bolt temporary fixing nut 14 strongly adheres to the inner peripheral surface of the upper end portion of the bolt hole 3 of the bottom steel plate 1 over the entire circumference in the circumferential direction. Accordingly, the space between the bolt temporary fixing nut 14 and the inner peripheral surface of the upper end portion of the bolt hole 3 of the bottom steel plate 1 (A portion in the figure) is hermetically sealed.

  After the bolt 5 is temporarily fixed to the bolt hole 3 of the bottom steel plate 1 as described above in a state where rotation is prevented, the temporary bolt fixing nut 14 is inserted into the bolt hole 3 as shown in FIG. The required area including the head 5b of the bolt 5 on the lower surface side of the bottom steel plate 1 temporarily fixed with the bolt 5 interposed therebetween, for example, the entire lower surface of the bottom steel plate 1 is subjected to a coating that is a preceding coating. The space between the head 5b of the bolt 5 and the lower surface of the bottom steel plate 1 (B portion in the figure) is sealed with the coating film 19.

  Further, the shaft portion 5a of the bolt 5 temporarily fixed to the bolt hole 3 of the bottom steel plate 1 through the bolt temporary fixing nut 14 is covered with the body portion 15a of the rust prevention cap 15 from the tip side, and the rust prevention The opening 15b of the cap 15 is attached to the cap mounting portion 17 of the bolt temporary fixing nut 14 so that the space between the opening 15b of the rust prevention cap 15 and the bolt temporary fixing nut 14 (in the drawing) C point) is hermetically sealed.

  By the above, the three portions A, B, and C in the figure are sealed, so that the contact with the outside air of the shaft portion 5a of the bolt 5 is blocked, and the shaft portion 5a of the bolt 5 is prevented from being rusted. As illustrated.

  Thereafter, the bottom steel plate 1 with the bolts 5 rust-prevented as described above attached to the bolt holes 3 is carried into the construction site, and the bottom steel plates 1 are arranged in the span direction on the main girder. After installation, as shown in FIG. 6 (c) (only one bottom steel plate 1 is shown in FIG. 6 (c)) above the butt ends of the adjacent bottom steel plates 1, each bottom steel plate 1 is shown. A bolt hole 4 having a required dimension larger than the outer diameter of the other axial end portion of the taper portion 16 of the bolt temporary fixing nut 14 is formed at a position corresponding to the bolt hole 3. The attachment plate 2 is placed from above, and the bolts 5 temporarily fixed to the bolt holes 3 of the bottom steel plate 1 are inserted into the bolt holes 4 of the attachment plate 2, respectively. One end portion of a rust prevention cap 15 attached to the shaft portion 5a of each bolt 5 projecting upward from the attachment plate 2 is After removing the rust prevention cap 15 by pulling it upward, the nut 6 is fitted to the shaft portion 5a of each bolt 5 via the washer 7, and the nut 6 is tightened to the bolt 5. As a result, the overlapping portions of the bottom steel plate 1 and the splicing plate 2 are respectively joined by bolts 5. In this way, the butt end portions of the adjacent bottom steel plates 1 can be connected to each other via the splicing plate 2.

JP 2004-176909 A Japanese Patent No. 9-250531

  However, according to the anti-corrosion technique for fastening bolts proposed by the present inventor in a previous application (Japanese Patent Application No. 2007-302596), the bottom steel plate 1 and the splicing plate 2 as two superposed steel plates are used. After the bolt 5 is temporarily fixed to the bolt hole 3 of the bottom steel plate 1 as one of the steel plates via a bolt temporary fixing nut 14, to one side surface portion of the bottom steel plate 1 including the head 5 b of the bolt 5. The bolt 5 is attached to the cap mounting portion 17 of the bolt temporary fixing nut 14 of the opening portion 15b of the rust prevention cap 15 which is mounted so as to cover the tip portion and the side surface of the shaft portion 5a of the bolt 5. The shaft portion 5a can be shielded from the outside air to prevent rust, and the effect of this rust prevention can be obtained from the shaft portion 5a of the bolt 5 in order to perform final tightening of the nut 6 with respect to the bolt 5. Until the point of removal The bolt 5 is temporarily fixed to the bolt hole 3 via the bolt temporary fixing nut 14 as described above, and the bottom including the bolt temporary fixing nut 14 and the head 5b of the bolt 5 is used. The bottom steel plate 1 in a state in which the bolt 5 is rust-prevented by painting on one side surface of the steel plate 1 and the anti-rust cap 15 is exposed to the outdoors and exposed to sunlight and rain. When the temperature change occurs and the bolt 5 attached to the bolt hole 3 of the bottom steel plate 1 changes in temperature with the temperature change of the bottom steel plate 1, the above-mentioned prevention attached to the shaft portion 5 a of the bolt 5. There is a concern that the airtightness inside the rust cap 15 may be affected.

  That is, in general, when a steel sheet is exposed to sunlight in summer, it may reach 60 ° C to 70 ° C. Therefore, when the bottom steel plate 1 in which the bolt 5 is temporarily fixed to the bolt hole 3 is exposed to sunlight and the temperature rises, the temperature of the bolt 5 temporarily fixed to the bolt hole 3 increases accordingly. The temperature of the flexible resin rust prevention cap 15 attached to the shaft 5a of the bolt 5 also rises, and depending on the material of the rust prevention cap 15, softening due to the temperature rise occurs. There is a concern that the tightness between the opening 15b of the rust prevention cap 15 and the cap mounting portion 17 of the bolt temporary fixing nut 14 is weakened, so that the airtightness inside the rust prevention cap 15 may be impaired.

  In the same manner as above, the opening 15b of the rust prevention cap 15 and the cap mounting portion 17 of the bolt temporary fixing nut 14 are maintained, and are temporarily fixed to the bolt hole 3 of the bottom steel plate 1 in the same manner as described above. When the temperature of the bolt 5 is increased, the temperature of the air enclosed in the rust prevention cap 15 attached to the shaft portion 5a of the bolt 5 is increased and the volume is expanded, and the internal pressure of the rust prevention cap 15 is increased. There is a concern that the rust prevention cap 15 may come off from the cap mounting portion 17 of the bolt temporary fixing nut 14 due to the fact that becomes higher than the external pressure.

  On the other hand, the bottom steel plate 1 exposed to the outside in a state where the bolt 5 is temporarily fixed to the bolt hole 3 decreases in temperature as the outside air temperature decreases, and is temporarily fixed to the bolt hole 3 accordingly. When the temperature of the bolt decreases, the air enclosed in the anticorrosion cap 15 attached to the shaft portion 5a of the bolt 5 decreases in temperature and contracts in volume, and the internal pressure of the anticorrosion cap 15 is negative. May be. At this time, if moisture due to rain water or the like is present in the opening portion 15 b of the rust prevention cap 15 attached to the cap attachment portion 17 of the bolt temporary fixing nut 14, the moisture is sucked into the rust prevention cap 15. There is also a concern that this may occur.

  Then, this invention arrange | positions so that the axial part of the volt | bolt temporarily fixed to the volt | bolt hole of one steel plate of two laminated steel plates made to join using a volt | bolt via a volt | bolt temporary fixing nut may be covered. Even if the temperature change of the bolt due to the temperature change of the one steel plate occurs in the state where the opening of the bolt anti-rust cap is attached to the cap attachment portion of the bolt temporary fixing nut, the bolt anti-rust An object of the present invention is to provide a bolt rust prevention method and a rust prevention cap for bolts used in the method, which can eliminate the possibility that the airtightness inside the rust cap is affected.

  In order to solve the above-mentioned problem, the present invention provides a shaft portion of a bolt inserted into a bolt hole of one of two stacked steel plates to be joined using a bolt, corresponding to claim 1. The bolt temporary fixing nut having one end side in the axial direction smaller than the bolt hole of the steel plate is screwed and tightened from one end side in the axial direction, and one axial end portion of the bolt temporary fixing nut is tightened. A bolt rust prevention cap having an opening on one end side of the body portion is put on the shaft portion of the bolt that is temporarily fixed to the bolt hole by wedged into the gap between the bolt hole of the steel plate. After that, the body portion is screwed onto the bolt shaft portion, and the opening portion is brought into close contact with the cap mounting portion at the other axial end portion of the bolt temporary fixing nut to prevent the bolt from being rusted. It is a bolt rust prevention method to be performed.

  Further, according to claim 2, one end side of the axial direction of the bolt is inserted into the bolt hole of one of the two stacked steel plates to be joined using the bolt, and the one end side in the axial direction is the steel plate. A bolt temporary fixing nut having a diameter smaller than that of the bolt hole is screwed and tightened from one end side in the axial direction, and one axial end portion of the bolt temporary fixing nut is connected to the bolt hole and the bolt of the steel plate. The shaft portion of the bolt that is temporarily fixed in the bolt hole is covered with the body portion by being wedged into the gap, and the opening portion of the body portion is disposed on the other axial end side of the bolt temporary fixing nut. A bolt rust prevention cap having a structure in which a screw portion for screwing on the shaft portion of the bolt is provided on the inner side of the body portion so as to be attached and closely attached to the cap attachment portion provided. .

  Further, in the above configuration, the screw portion is provided inside the body portion so as to be screwed to a portion near the tip of the shaft portion of the bolt when the body portion is disposed so as to cover the shaft portion of the bolt. And

According to the present invention, the following excellent effects are exhibited.
(1) One end side in the axial center direction has a smaller diameter than the bolt hole of the steel plate at the shaft portion of the bolt inserted into the bolt hole of one steel plate of the two superposed steel plates to be joined using bolts. The bolt temporary fixing nut is screwed and tightened from one end side in the axial direction, and one axial end portion of the bolt temporary fixing nut is wedged into the gap between the bolt hole of the steel plate and the bolt. After covering the bolt shaft portion temporarily fixed in the bolt hole with a bolt antirust cap having an opening on one end side of the body portion, the body portion is screwed onto the bolt shaft portion, A bolt rust prevention method for performing rust prevention of the bolt by bringing the opening into close contact with the cap mounting portion at the other axial end of the bolt temporary fixing nut, and joining using the bolt One of the two stacked steel plates A bolt temporary fixing nut whose one end side in the axial center direction is smaller in diameter than the bolt hole of the steel plate is screwed from one end side in the axial direction to the shaft portion of the bolt inserted into the bolt hole of the plate. Tighten the axial end of the bolt temporary fixing nut in a wedge shape into the gap between the bolt hole of the steel plate and cover the shaft portion of the bolt temporarily fixed in the bolt hole with the body portion And the opening of the body portion is attached to and closely attached to a cap mounting portion provided on the other axial end side of the bolt temporary fixing nut, and further, the shaft of the bolt is disposed inside the body portion. Since it is a rust prevention cap for bolts having a configuration in which a threaded portion is provided for screwing to the portion, the shaft portion of the bolt temporarily fixed to the bolt hole of the one steel plate via a bolt temporary fixing nut is used for the bolt. Anti-rust cap body In the covered state, using the tightening axial force of the screw portion of the body portion against the bolt, the opening portion of the bolt anti-rust cap can be brought into close contact with the cap mounting portion of the bolt temporary fixing nut. It is possible to eliminate the possibility that the adhesiveness of the opening of the bolt anti-rust cap to the cap mounting portion of the bolt temporary fixing nut is affected by temperature change. Therefore, there is a risk that the bolt anti-rust cap may come off from the cap mounting portion of the bolt temporary fixing nut as the internal pressure of the bolt anti-rust cap rises, or that the opening and The possibility of sucking up moisture through the space between the bolt temporary fixing nut and the cap mounting portion can be eliminated, and the rust prevention effect of the bolt can be maintained well.
(2) The screw part is provided inside the body part so as to be screwed to a portion near the tip of the shaft part of the bolt when the body part is arranged so as to cover the shaft part of the bolt. Thus, the number of rotations required when the screw portion is screwed onto the bolt shaft portion and tightened can be reduced, and the work of mounting the bolt on the rust prevention cap for the bolt can be reduced. And can save time.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 (a) (b) and FIG. 2 (b) (b) are two laminated steel plates as an embodiment of the bolt rust prevention method of the present invention and the bolt rust prevention cap used in the method, The bolt 5 used for joining the bottom steel plate 1 and the splicing plate 2 of the same composite floor slab as shown in FIG. 3 is shown in the bolt hole 3 of the bottom steel plate 1 in FIGS. 6 (a), (b) and (c). This shows a case where it is applied for rust prevention in a state where it is temporarily fixed via a bolt temporary fixing nut 14 similar to the bolt temporary fixing nut 14 in the fastening bolt rust prevention device, and has the following configuration. .

  That is, the bolt rust prevention cap 20 of the present invention is temporarily fixed to the other end side in the axial direction of the cylindrical body portion 21 whose one end side in the axial direction is closed in order to cover the shaft portion 5 a of the bolt 5. An opening 22 is provided for mounting on a cylindrical cap mounting portion 17 provided on the nut 14, and a bolt temporary fixing nut 14 is provided inside the body portion 21 through the bolt hole 3 of the bottom steel plate 1. Then, a screw part (female screw part) 23 for screwing onto the shaft part 5a of the bolt 5 temporarily fixed is provided.

  More specifically, the bolt anti-rust cap 20 is made of metal such as copper, brass, aluminum, or synthetic resin so as to allow the required elastic deformation.

  The opening 22 of the bolt antirust cap 20 has an inner diameter that is the same as or slightly smaller than the outer diameter of the cap mounting portion 17 of the temporary bolt fixing nut 14. As a result, the bolt 5 that is temporarily fixed to the bolt hole 3 of the bottom steel plate 1 via the bolt temporary fixing nut 14, the screw portion 23 provided inside the body portion 21 of the bolt antirust cap 20. By screwing and tightening to the shaft part 5a, the opening 22 of the bolt anti-rust cap 20 is attached so as to forcibly cover the outer periphery of the cap attaching part 17 of the bolt temporary fixing nut 14. The inner peripheral surface of the opening 22 of the bolt rust prevention cap 20 can be brought into close contact with the outer peripheral surface of the cap mounting portion 17 of the temporary bolt fixing nut 14 over the entire circumference. Therefore, the space between the opening 22 of the bolt rust prevention cap 20 and the bolt temporary fixing nut 14 can be sealed.

  The body portion 21 of the bolt anti-rust cap 20 covers the shaft portion 5 of the bolt 5 that is temporarily fixed to the bolt hole 3 of the bottom steel plate 1 via the bolt temporary fixing nut 14 by the body portion 21. When the opening 22 is arranged to be attached to the cap attaching part 17 of the bolt temporary fixing nut 14, the axially opposite opening side of the body part 21 is arranged to face the vicinity of the tip of the shaft part 5a of the bolt 5. The threaded portion 23 is provided only on the inner peripheral surface near the end, and the portion of the body portion 21 closer to the opening side than the threaded portion 23 has an inner diameter dimension of the portion of the bolt 5. It is designed to be slightly larger than the outer diameter of the part 5a. As a result, the screw portion 23 of the bolt anticorrosion cap 20 is screwed onto the shaft portion 5a of the bolt 5 temporarily fixed to the bolt hole 3 of the bottom steel plate 1 via the bolt temporary fixing nut 14 and tightened. The tightening amount (the number of rotations) required when performing the operation to be set can be set small.

  Specifically, when a screw portion is provided in the vicinity of the opening 22 in the body portion 21 of the bolt rust prevention cap 20, the bolt 5 temporarily fixing the bolt 5 to the bolt hole 3 of the bottom steel plate 1. In order to attach the opening 22 of the bolt anti-rust cap 20 to the cap mounting portion 17 of the temporary fixing nut 14, the screw portion is tightened over the entire length of the shaft portion 5 a of the bolt 5 protruding from the bolt temporary fixing nut 14. Therefore, it is necessary to increase the number of rotations of the rust prevention cap 20 for bolts when performing the tightening operation. For example, as shown in FIG. When the opening 22 is mounted on the cap mounting portion 17 of the bolt temporary fixing nut 14, the opening 22 is provided on the inner side of the body portion 21 of the bolt antirust cap 20 near the end on the side opposite to the opening in the axial direction. If the screw thread of the portion 23 and the screw thread of the shaft portion 5a of the bolt 5 are engaged with each other by about four threads, the bolt anticorrosion cap 20 that covers the shaft portion 5a of the bolt 5 is tightened four times. The opening 22 of the bolt rust prevention cap 20 can be attached to the cap attachment portion 17 of the bolt temporary fixing nut 14 only by the operation described above. Therefore, it is possible to reduce labor and time required for tightening work for mounting the bolt anti-rust cap 20 to the shaft portion 5a of the bolt 5 temporarily fixed via the bolt temporary fixing nut 14. It is.

  Furthermore, a required portion of the outer peripheral surface of the body portion 21 of the bolt rust prevention cap 20, for example, a portion on the side opposite to the opening side from a portion where the screw portion 23 is provided on the inner side in the axial direction of the body portion 21. On the outer peripheral surface of the end portion, a non-slip portion 24 is provided which is formed by engraving a number of grooves 24a parallel to the axial direction at a required pitch in the circumferential direction.

  Using the rust prevention cap 20 for bolts of the present invention having the above-described configuration, the bolt used for joining the bottom steel plate 1 and the splicing plate 2 of the composite floor slab as two superposed steel plates as shown in FIG. 2 is temporarily fixed to the bolt hole 3 of the bottom steel plate 1 via a bolt temporary fixing nut 14, in order to prevent rust, as shown in FIG. A bolt (high-strength bolt) 5, for example, a shaft portion 5 a of a torcia-type bolt 5, and a bolt temporary fixing nut 14 and a taper portion 16 are provided in a bolt hole 3 of 1. The female screw part 18 is screwed by fitting from one end side in the center direction, the bolt temporary fixing nut 14 is fastened to the bolt 5, and the tapered part 16 of the bolt temporary fixing nut 14 is bolted to the bottom steel plate 1. The gap between the upper end of the hole 3 and the bolt 5 By biting into a wedge shape, the outer peripheral surface of the taper portion 16 of the bolt temporary fixing nut 14 is tightly adhered to the inner peripheral surface of the upper end portion of the bolt hole 3 of the bottom steel plate 1 over the entire circumference. The bolt 5 is temporarily fixed to the bolt hole 3 of the bottom steel plate 1 while being prevented from rotating, and between the bolt temporary fixing nut 14 and the inner peripheral surface of the upper end portion of the bolt hole 3 of the bottom steel plate 1 (see FIG. Seal A).

  Thereafter, the bolt rust prevention cap 20 of the present invention is covered from the opening 22 side to the shaft portion 5a of the bolt 5 temporarily fixed to the bolt hole 3 of the bottom steel plate 1 via the bolt temporary fixing nut 14. Thus, a portion closer to the opening side than the screw portion 23 in the body portion 21 is disposed on the outer periphery of the shaft portion 5 a of the bolt 5. Next, the bolt rust prevention cap 20 is rotated in a clockwise direction in plan view, and the screw portion 23 is screwed onto the shaft portion 5a of the bolt 5 to be tightened. As shown, the opening 22 of the bolt anti-rust cap 20 is mounted on the cap mounting portion 17 of the bolt temporary fixing nut 14. Thereby, the space | interval (C place in a figure) between the opening part 22 of the said rust prevention cap 20 for bolts, and the bolt temporary fixing nut 14 is sealed.

  In addition, a required region including the head 5b of the bolt 5 temporarily fixed to the bolt hole 3 of the bottom steel plate 1 through the bolt temporary fixing nut 14 as described above while being prevented from rotating, for example, the bottom As shown in FIG. 2 (b), the entire surface of the lower surface of the steel plate 1 is subjected to a coating that is a preceding coating, so that the space between the head 5b of the bolt 5 and the lower surface of the bottom steel plate 1 (in the drawing). The B part) is sealed with the coating film 19.

  The bolt head 5b is included before the bolt antirust cap 20 is attached to the shaft portion 5a of the bolt 5 temporarily fixed to the bolt hole 3 of the bottom steel plate 1 via the bolt temporary fixing nut 14. You may make it perform the prior coating to the lower surface of the bottom steel plate 1. FIG.

  As described above, the three parts A, B, and C in the above figure are sealed so that the contact with the outside air of the shaft part 5a of the bolt 5 is blocked, so that the shaft part 5a of the bolt 5 is blocked. Rust prevention is achieved. 2A and 2B, the same components as those shown in FIGS. 6A, 6B and 6C are designated by the same reference numerals.

  The bolt anticorrosion cap 20 is made of a metal such as copper, brass, aluminum or the like that can allow the required elastic deformation, or is made of a synthetic resin, and the bolt shaft portion 5a of the screw portion 23 provided inside the body portion 21. Since the opening 22 is forcibly attached to the cap attaching portion 17 of the bolt temporary fixing nut 14 by using the tightening axial force against the bolt, the bolt temporary provision of the opening 22 of the bolt antirust cap 20 is provided. It is possible to suppress the possibility that the adhesion of the fixing nut 14 to the cap mounting portion 17 is affected by the temperature change.

  Therefore, the bolt 5 is temporarily fixed to the bolt hole 3 via the bolt temporary fixing nut 14 and the temporarily fixed bolt 5 is rust-prevented using the bolt anti-rust cap 20 of the present invention. When the bottom steel plate 1 is exposed to the outdoors, for example, the temperature rises due to sunlight, and the bolt 5 temporarily fixed to the bolt hole 3 rises in temperature with the temperature rise of the bottom steel plate 1, the bolt protection Although the temperature of the rust cap 20 itself also rises, in this case as well, it is possible to suppress the possibility that the adhesion of the opening 22 of the bolt antirust cap 20 to the cap mounting portion 17 of the temporary bolt fixing nut 14 will be reduced.

  On the other hand, the bolt 5 is temporarily fixed to the bolt hole 3 via a bolt temporary fixing nut 14 and the bolt 5 temporarily fixed using the bolt anti-rust cap 20 of the present invention is rust-prevented. As the temperature of the certain bottom steel plate 1 decreases, the temperature of the bolt 5 temporarily fixed in the bolt hole 3 of the bottom steel plate 1 decreases, and the air enclosed in the rust prevention cap 20 for the bolt is reduced. When the temperature is lowered, the volume of the rust preventive cap 20 is reduced, and the inside of the bolt rust preventive cap 20 may become a negative pressure with respect to the external air pressure. In this case, the outside of the opening 22 of the bolt rust preventive cap 20 Even if water droplets due to rain water or the like are present, the water droplets are prevented from rust-proof caps for bolts due to the high adhesion of the openings 22 of the bolt rust-proof caps 20 to the cap mounting portions 17 of the bolt temporary fixing nuts 14. It can be eliminated a possibility that sucked inside the 20.

  Further, the bolt rust prevention cap 20 is formed by tightening the screw portion 23 with respect to the shaft portion 5a of the bolt 5, so that the direction of the front end side of the shaft portion 5a of the bolt 5, that is, the bolt temporary fixing nut 14 is increased. Displacement in a further away direction is constrained. For this reason, as described above, the temperature of the bolt 5 temporarily fixed to the bolt hole 3 rises as the temperature of the bottom steel plate 1 rises, and the air enclosed in the rust prevention cap 20 for the bolt rises in temperature. Then, even if the internal pressure of the bolt anticorrosion cap 20 becomes higher than the external air pressure due to the expansion of the volume, the possibility of coming off from the cap mounting portion 17 of the bolt temporary fixing nut 14 is eliminated. The

  Thus, according to the bolt rust prevention method of the present invention and the bolt rust prevention cap 20 used in the method, it is caused by the temperature change of the bolt 5 temporarily fixed to the bolt hole 3 accompanying the temperature change of the bottom steel plate 1. Thus, the air enclosed in the bolt rust prevention cap 20 covering the shaft portion 5a of the bolt 5 expands and contracts, and the pressure inside the bolt rust prevention cap 20 becomes the external pressure. Even if it becomes higher or lower, it is possible to eliminate the possibility that the airtightness of the bolt antirust cap 20 is affected. Therefore, the antirust effect of the bolt 5 can be maintained well.

  The bolt 5 is temporarily fixed to the bolt hole 3 via the bolt temporary fixing nut 14 as described above, and the bolt 5 temporarily fixed using the bolt anti-rust cap 20 is rust-proof. The bottom steel plate 1 is then brought into the construction site, and after the bottom steel plate 1 is arranged in the span direction on the main girder, on the upper side of the butt ends of the adjacent bottom steel plates 1, The attachment plate 2 formed by drilling the bolt holes 4 at positions corresponding to the bolt holes 3 of the bottom steel plates 1 is placed from above by the same procedure as described in FIG. After the bolts 5 temporarily fixed to the bolt holes 3 of the bottom steel plate 1 are inserted into the bolt holes 4 of the attachment plate 2, the shafts of the bolts 5 projecting upward from the attachment plate 2. Turn the bolt anti-rust cap 20 mounted on the part 5a counterclockwise in plan view. Then, the screw portion 23 is detached from the shaft portion 5a of the bolt 5 and then removed upward. Thereafter, the nut 6 is fitted and tightened to the shaft portion 5a of each bolt 5 via the washer 7, thereby 1 and the joining plate 2 may be joined together by bolts 5 so that the butt end portions of the adjacent bottom steel plates 1 are connected via the joining plate 2.

  In addition, this invention is not limited only to the said embodiment, In FIG.2 (b), the thread of the screw part 23 of the antirust cap 20 for bolts, and the thread of the axial part 5a of the bolt 5 are shown. The bolt rust prevention cap 20 is shown as being able to be attached to the shaft portion 5a of the bolt 5 by tightening so that about 4 threads are engaged, but the size of the shaft portion 5a of the bolt 5 and the bolt Tightening required for mounting the rust preventive cap 20 for bolts depending on the magnitude of the differential pressure from the external air pressure assumed to act with the temperature change of the air sealed inside the rust preventive cap 20 The amount of inclusion may be increased or decreased as appropriate.

  The anti-slip part 24 provided on the body part 21 is provided with an anti-slip means other than the groove 24a, such as roughening the outer peripheral surface or providing a protrusion, as long as the operator can easily grip and rotate the body part 21. May be adopted, and the position to be provided may be changed as appropriate.

  The diameter of the opening 22 may be appropriately changed according to the outer diameter of the cap mounting portion 17 of the bolt temporary fixing nut 14 used for temporarily fixing the bolt 5.

  If it is a place where it is desired to attach the bolt 5 to the bolt hole in advance so as not to drop off, it may be applied to any place where the steel plates other than the bottom steel plate 1 and the splicing plate 2 are joined.

  Of course, various modifications can be made without departing from the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of a rust prevention cap for bolts used in the bolt rust prevention method of the present invention, in which (a) is a schematic side view, and (b) is a substantially cut side view at an axial center portion. Fig. 1 shows how to use the rust prevention cap for bolts in Fig. 1. (a) shows a state in which the shaft portion of the bolt temporarily fixed to the bolt hole of the bottom steel plate through a temporary bolt fixing nut is covered (b). ) Is a partially cut schematic side view showing a state in which the screw portion inside the body portion is screwed into the shaft portion of the bolt and the opening portion is attached to the cap attaching portion of the bolt temporary fixing nut. It is a cut side view which shows the general connection structure through the joining board of the butt | matching edge parts of the bottom steel plate of an adjacent synthetic floor slab. An outline of an example of a conventionally proposed method for holding the bolt in the bolt hole of the bottom steel plate is shown. (A) shows a state in which the bolt is held in the bolt hole of the bottom steel plate. (C) is a cut side view showing a state in which an attachment plate is placed on the upper side of an adjacent bottom steel plate, and (c) is a cut side view showing a state in which the adjacent bottom steel plates are connected via an attachment plate. It is the schematic which shows the anti-corrosion cap conventionally proposed as one of the means for performing the anti-corrosion of the axial part and bolt of the bolt after the fastening used for joining of two board | plates. The outline | summary of the rust prevention method and apparatus of the fastening bolt which this inventor has proposed in the previous application is shown, (i) temporarily fixed the bolt to the bolt hole of the bottom steel plate through the bolt temporary fixing nut. (B) shows the state where the bottom surface of the bottom steel plate including the bolt head is painted and the rust prevention cap is attached to the bolt, and (c) shows the state where the attachment plate is joined to the bottom steel plate. It is a partially cut schematic side view shown.

Explanation of symbols

1 Bottom steel plate (one steel plate)
2 Connecting plate (the other steel plate)
3 Bolt hole 5 Bolt 5a Shaft portion 5b Head portion 14 Bolt temporary fixing nut 17 Cap mounting portion 20 Bolt rust prevention cap 21 Body portion 22 Opening portion 23 Screw portion

Claims (3)

  The shaft portion of the bolt inserted into the bolt hole of one of the two stacked steel plates to be joined using the bolt is configured such that one end side in the axial direction has a smaller diameter than the bolt hole of the steel plate. A bolt temporary fixing nut is screwed and tightened from one end side in the axial direction, and one end portion in the axial direction of the bolt temporary fixing nut is wedged into the gap between the bolt hole of the steel plate and the bolt. The bolt shaft portion temporarily fixed in the hole is covered with a bolt rust prevention cap having an opening portion on one end side of the body portion, and then the body portion is screwed to the bolt shaft portion so that the opening portion is formed. The bolt rust prevention method is characterized in that the bolt is rust-prevented by being brought into close contact with the cap mounting portion at the other axial end of the bolt temporary fixing nut.   The shaft portion of the bolt inserted into the bolt hole of one of the two stacked steel plates to be joined using the bolt is configured such that one end side in the axial direction has a smaller diameter than the bolt hole of the steel plate. A bolt temporary fixing nut is screwed and tightened from one end side in the axial direction, and one axial end portion of the bolt temporary fixing nut is wedged into the gap between the bolt hole and the bolt of the steel plate, The shaft portion of the bolt that is temporarily fixed in the bolt hole is covered with the body portion, and the opening portion of the body portion is attached to the cap mounting portion provided on the other end side in the axial center direction of the bolt temporary fixing nut. And a rust preventive cap for bolts having a structure in which a screw portion for screwing onto the shaft portion of the bolt is provided inside the body portion.   The bolt portion according to claim 2, wherein a screw portion is provided inside the body portion so as to be screwed to a portion near the tip of the shaft portion of the bolt when the body portion is disposed so as to cover the shaft portion of the bolt. Anti-rust cap.

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