JP5436617B2 - How to remove rivets - Google Patents

Description

  The present invention relates to a rivet removing method for removing a rivet in which a plurality of steel plates overlapped by a large steel structure are joined, and more particularly to a rivet removing method for forming a through hole in a rivet and pulling out the rivet.

  In recent years, in large steel structures such as bridges, repair has been performed in which a rivet formed by joining a plurality of overlapping steel plates is replaced with a high-strength bolt. In this repair, since it is necessary to remove the rivet from the rivet hole of the steel plate material without damaging the steel plate material which is the joining base material, conventionally, it has been performed through the process shown in FIG.

  That is, first, from the state shown in FIG. 13A, as shown in FIG. 13B, the heads 150b and 150c at both ends of the rivet 150A are cut by a grinder or the like. Next, from the state shown in FIG. 13B, as shown in FIG. 13C, the upper surface 150d formed on one end side of the rivet 150A is placed on the upper side with a hammer or the like (upper side in FIG. 13). The shaft portion 150a of the rivet 150A is punched from the rivet hole RA of the steel plate material and removed. Finally, as shown in FIG. 13D, a high strength bolt 160 is attached to the rivet hole RA of the steel plate material.

  Here, as a method of removing the rivet by a method other than hitting with a hammer or the like, a method as described in Patent Document 1 is known. In this method, first, as shown in FIG. 14, in the state where the drilling rivet 250A is attached to the rivet hole RA of the joining base material SB such as aluminum, the threaded mandrel 280 is moved to the inner peripheral surface of the drilling rivet 250A. It is screwed in while forming a screw part with respect to 250f. Next, the threaded mandrel 280 is pulled upward (upper side in FIG. 14) in a state where the threaded mandrel 280 is engaged with the inner peripheral surface 250f of the drilling rivet 250A. Thereby, the drilling rivet 250A can be removed from the joining base material SB.

JP 2001-293536 A

  However, when removing a rivet that joins a plurality of steel plates that overlap each other with a large steel structure such as a bridge, there are the following problems. First, since the method of removing the rivet by hitting it with a hammer or the like is a dangerous work, a high level of skill in hitting is required. In addition, a rivet that is difficult to punch requires a lot of work time because the work is performed repeatedly for several tens of minutes. In addition, there was a problem that the noise was high when hitting.

  On the other hand, the method of removing the drilling rivet described in Patent Document 1 has a problem that the rivet used in the large steel structure cannot be removed. That is, in a large steel structure such as a bridge, there are joint portions where about four steel plates overlap each other, and the length of a rivet used in this joint portion is about 100 mm. Screwing such a relatively long rivet while forming a screw hole with a threaded mandrel is extremely complicated and practically impossible.

  In other words, the rivet used in the large steel structure is different from the drilling rivet as in the above-mentioned Patent Document 1, and is not formed with a through-hole from the beginning, and is a relatively long one that joins a plurality of steel plate materials. It is. For this reason, it is very difficult to form the screw holes. Thus, there has been a problem that conventional and generally known rivet removal methods cannot be applied to rivets used in large steel structures such as bridges.

  Therefore, the present invention has been made to solve the above-described problems, and when removing a rivet that joins a plurality of steel plates that overlap each other with a large steel structure, noise caused by striking can be eliminated and safely It is an object of the present invention to provide a rivet removing method capable of performing a removing operation and reducing the working time.

  A rivet removing method according to the present invention is a method for removing a rivet in which a plurality of steel plates overlapped by a large steel structure are joined, and is a head that removes at least one of the heads at both ends of the rivet. A part removing step, a through hole forming step of forming a through hole coaxial with the rivet and having a diameter smaller than the diameter of the shaft of the rivet, and inserting a shaft portion of the pin from one end side of the rivet into the through hole A pin insertion step of engaging a diameter-enlarged portion of a pin larger in diameter than the shaft portion of the pin with an end surface formed on one end side of the rivet, and a shaft portion of the pin protruding from the through-hole. And a pin pulling step for removing the rivet by pulling out to the other end side.

  In this case, first, the head of the rivet is removed and a through-hole is formed in the rivet, so that the bearing joining force and the shear resistance force of the rivet for joining a plurality of steel plate materials are reduced, and the rivet can be easily removed. And, with the enlarged diameter part of the pin engaged with the end surface formed on one end side of the rivet, the shaft part of the pin popping out from the through hole is pulled out with a dedicated pulling device, so no special skill is required The rivet can be removed. Further, since the rivet is pulled out without hitting it with a hammer or the like, noise caused by hitting can be eliminated and the removal work can be performed safely. Furthermore, since the drawing work time can be several minutes at most, the work time can be reduced.

  In the rivet removing method according to the present invention, it is preferable that in the pin pulling step, the shaft portion of the pin is pulled out without rotating a screw portion formed on the shaft portion of the pin using a rotary pulling device. .

  In this case, since the rotary pulling device pulls out the shaft portion of the pin without rotating the screw portion, the force with which the pin is pulled to the other end side of the rivet can be strengthened, and the rivet can be removed more securely. be able to.

  Moreover, in the rivet removing method according to the present invention, it is preferable that, in the pin insertion step, an enlarged diameter portion of the pin formed in a tapered shape is engaged with an end surface of the rivet.

  In this case, since the enlarged diameter portion of the pin is tapered, the enlarged diameter portion of the pin and the end surface of the rivet are engaged, so that the axial center of the through hole and the axial center of the axial portion of the pin And easily match. That is, the axial alignment between the through hole and the shaft portion of the pin is facilitated.

  According to the rivet removing method of the present invention, it is possible to remove a rivet obtained by joining a plurality of steel plates that overlap each other with a large steel structure. In particular, noise due to impact can be eliminated, the removal work can be performed safely, and the work time can be reduced.

It is the perspective view which showed the attachment part of the bridge. It is the perspective view which looked at the attachment part shown in FIG. 1 from the arrow X direction. It is the perspective view which showed the state from which some rivets of FIG. 1 were removed. It is the figure which showed the state in which the high strength volt | bolt was attached to the rivet hole of FIG. It is the figure which showed each process of the rivet removal method of this embodiment. It is the figure which showed typically sectional drawing along the YY line of FIG. It is the figure which showed the state which removed the head of the both ends of the rivet of FIG. It is the figure which showed the state which formed the through-hole in the rivet of FIG. It is the figure which showed the state which inserted the axial part of the pin in the through-hole of FIG. It is the figure which showed the state which set the rotary extraction apparatus with respect to the screw part of the pin which protrudes from the through-hole of FIG. It is the figure which showed the state which pulled out the rivet of FIG. 10 from the rivet hole. FIG. 10 shows a modified embodiment of the pin of FIG. 9. It is the figure which showed the process in which the rivet is hit and removed in the conventional rivet removal method. In the conventional removal method of a drilling rivet, it is the figure which showed the state in which a screw part is formed in the internal peripheral surface of a drilling rivet.

  An embodiment of a rivet removing method according to the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a connecting portion 1 of a bridge which is a large steel structure. FIG. 2 is a perspective view of the contact portion 1 shown in FIG. 1 when viewed from the X direction.

  As shown in FIG. 1, the attachment portion 1 mainly includes a joint member 10 having an L-shaped cross section, a long attachment plate 20 disposed under the joint member 10, and the attachment portion. An elongated thickening plate 30 disposed under the plate 20 and an upright member 40 extending perpendicularly to the attachment plate 20 and the thickening plate 30 are provided.

  In this attachment part 1, as shown in FIG. 2, the plane part 11 of the joint member 10, the end part of the attachment plate 20, the end part of the thickening plate 30, and the flange part 41 of the upright member 40 are provided. It is joined by two rivets 50A. Further, as shown in FIG. 1, the splicing plate 20 and the thickening plate 30 are joined by a plurality of rivets 50B.

  In the present embodiment, the two rivets 50 </ b> A and a part of the rivets 50 </ b> B are replaced with the high-strength bolts 60 in order to repair the attachment portion 1. That is, as shown in FIG. 3, the two rivets 50A and a part of the rivets 50B are removed, and as shown in FIG. 4, the high strength bolt 60 is attached to the rivet hole RA where the rivets 50A and 50B are attached. It is supposed to be.

  Here, the rivets 50A and 50B will be described. The rivets 50A and 50B are attached by the same method as the conventional method used when joining a plurality of steel plate materials of a large steel structure. That is, rivets 50A and 50B having a shaft portion 50a (see FIG. 6) with a diameter of 22.0 mm are prepared, and a plurality of steel plate materials (planar portion 11, splicing plate 20, thickening plate 30) which are joining base materials. , Flange portion 41) is formed with a rivet hole RA having a diameter of 23.5 mm (diameter of rivet hole RA = diameter of shaft portion 50a + 1.5 mm). Then, after the rivets 50A and 50B are heated in a furnace, the shaft portion 50a is inserted into the rivet hole RA, and the end of the shaft portion 50a protruding from the rivet hole RA is crushed by hitting with a rivet hammer.

  Thereby, the heads of the rivets 50A and 50B are formed, and the gap between the rivet hole RA and the shaft portion 50a is filled, and the joining by the rivets 50A and 50B is completed. As a result, the rivets 50A and 50B are configured to join a plurality of steel plate materials with a bearing support force and a shear resistance force. The rivets 50A and 50B of the present embodiment are rivets attached through the above-described processes, and are not small rivets for joining thin plates such as aluminum.

  When removing the rivets 50A and 50B, conventionally, a method of punching the rivets 50A and 50B by hitting the shaft 50a of the rivets 50A and 50B with the heads removed with a hammer or the like has been employed. However, since the method of removing the rivets 50A and 50B by hitting with a hammer or the like is a work that involves danger, a high level of skill in hitting is required. Further, depending on the rivets 50A and 50B, which are difficult to punch, the work of tapping several times for several tens of minutes requires a lot of work time. In addition, there was a problem that the noise was high when hitting.

  Therefore, in the present embodiment, in order to solve the above-described problems, through holes are formed in the rivets 50A and 50B, and the rivets 50A and 50B are pulled out using dedicated pins. Hereinafter, the rivet removing method of the present embodiment will be described in detail with reference to FIGS.

  FIG. 5 is a view showing each step of the rivet removing method of the present embodiment. FIG. 6 is a diagram schematically showing a cross-sectional view taken along line YY of FIG. In the present embodiment, a method for removing the rivet 50A will be described. However, since the method for removing the rivet 50B is the same, the method for removing the rivet 50B is omitted.

  As shown in FIG. 6, the rivet 50 </ b> A joins the four steel plate materials of the flat portion 11 of the joint member 10, the attachment plate 20, the thickening plate 30, and the flange portion 41 of the upright member 40. Thus, in the part which joins four steel plate materials, the length of the shaft part 50a of the rivet 50A is about 100 mm, and a relatively long rivet 50A is used.

  First, a head removing process is performed on the rivet 50A (step S1 in FIG. 5). That is, as shown in FIG. 7 from the state shown in FIG. 6, using a grinder (“grinding machine”), “Atoler” manufactured by Nitto Koki Co., Ltd., “Rivet Reamer” manufactured by Nichiwa Co., Ltd., etc. The head 50b on one end side and the head 50c on the other end side of the rivet 50A are removed. Thereby, a planar end surface 50d is formed on one end side of the rivet 50A, and a planar end surface 50e is formed on the other end side of the rivet 50A. In the present embodiment, one end side of the rivet 50A means the lower side of the figure with respect to the rivet 50A, and the other end side of the rivet 50A means the upper side of the figure with respect to the rivet 50A.

  Next, a through hole forming step is performed (step S2 in FIG. 5). That is, as shown in FIG. 8 from the state shown in FIG. 7, the operator forms a through hole 50f coaxial with the rivet 50A and having a diameter smaller than the diameter of the shaft portion 50a by using a dedicated drilling machine (not shown). To do. Here, the dedicated drilling machine is, for example, “Atoler” manufactured by Nitto Koki Co., Ltd., which is portable and can be easily carried by an operator, and capable of drilling 100 mm or more in steel. It is. The formed through hole 50f is a hollow round hole having a diameter of about 18 mm.

  Subsequently, a pin insertion process is performed (step 3 in FIG. 5). That is, as shown in FIG. 9, the operator inserts the shaft portion 70a of the pin 70 into the through hole 50f. Here, the pin 70 has a shaft portion 70a having a small diameter, an enlarged diameter portion 70b having a larger diameter than the shaft portion 70a, and a large diameter portion 70c having a larger diameter than the enlarged diameter portion 70b. A screw portion 70a1 is formed in the shaft portion 70a so that the screw portion 70a1 can pass through the through hole 50f in a non-contact manner. The enlarged diameter portion 70b is formed in a tapered shape, and has a diameter larger than the diameter of the through hole 50f on one end side (lower side in FIG. 9) and a diameter on the other end side (upper side in FIG. 9). It is smaller than the diameter of 50f. The diameter of the large diameter portion 70c is smaller than the diameter of the rivet hole RA.

  Thus, in the pin insertion step, when the shaft portion 70a of the pin 70 is inserted from one end side (lower side in FIG. 9) of the rivet 50A into the through hole 50f, the diameter-expanded portion 70b of the pin 70 is formed on the end surface 50d of the rivet 50A. Get caught (engaged). At this time, since the diameter-expanded portion 70b of the pin 70 is formed in a taper shape, even if the shaft center of the through hole 50f and the shaft center of the shaft portion 70a of the pin 70 are slightly deviated from each other, they naturally match. become. That is, the axial alignment of the through hole 50f and the shaft portion 70a of the pin 70 can be easily performed.

  Finally, a pin pulling process is performed (step 4 in FIG. 5). That is, first, as shown in FIG. 10, the operator sets the rotary pulling device 80 from the other end side (the upper side in FIG. 10) of the rivet 50 </ b> A to the surface of the flat portion 11 of the joint member 10. The screw portion 70a1 of the pin 70 protruding from 50f is fitted. Here, the rotary pulling device 80 is, for example, a “center wrench” manufactured by Nichiwa Co., Ltd., which is portable and can be easily carried by an operator, and can be loosened with safety and low noise. . The rotary pulling device 80 can loosen a screw having a length of 100 mm or more by a hydraulic rotational torque. The rotary pulling device 80 may be an electric type.

  Thus, in the pin pulling process, when the rotary pulling device 80 is operated, the rotary pulling device 80 tightens and pulls up the screw 70a1 of the pin 70, so that the screw 70a1 of the pin 70 does not rotate and the pin 70 Moves upward in FIG. At this time, the rivet 50A also moves to the upper side in FIG. As a result, as shown in FIG. 11, the shaft portion 50a of the rivet 50A is pulled out from the rivet hole RA of the joining base material (the flat surface portion 11, the attachment plate 20, the thickening plate 30, and the flange portion 41) (FIG. 3). reference). After that, as shown in FIG. 4, the high strength bolt 60 is attached to the rivet hole RA.

The effect of this embodiment is demonstrated.
According to the rivet removing method of the present embodiment, as shown in FIG. 7, the heads 50b and 50c at both ends of the rivet 50A are removed, and the through holes 50f are formed in the rivet 50A as shown in FIG. In addition, the bearing support force and the shear resistance of the rivet 50A that joins the flat surface portion 11, the attachment plate 20, the thickening plate 30, and the flange portion 41 are reduced, and the rivet 50A can be easily removed. Then, as shown in FIG. 11, in order to pull out the screw portion 70a1 of the pin 70 protruding from the through hole 50f with the rotary pulling device 80 in a state where the enlarged diameter portion 70b of the pin 70 is engaged with the end surface 50d of the rivet 50A. The rivet 50A can be removed without requiring special skills. Further, since the rivet 50A is pulled out without hitting it with a hammer or the like, noise due to hitting can be eliminated and the removal work can be performed safely. Furthermore, since the drawing work time can be several minutes at most, the work time can be reduced.

  Further, according to the rivet removing method of the present embodiment, as shown in FIG. 11, the rotary pulling device 80 does not rotate the screw portion 70a1 with a hydraulic strong rotational torque, and the shaft portion 70a of the pin 70 is removed. Pull out. For this reason, the force by which the pin 70 is pulled to the other end side (FIG. 11 upper side) of the rivet 50A can be strengthened, and the rivet 50A can be removed more reliably. That is, when the rivet is longer than 100 mm, when the rivet is deformed, or when a hole shift occurs in the joining base material, the rivet can be reliably removed with a strong pulling force. .

  Here, conventionally, as a method of removing the rivet 50A, there are a method of hitting the rivet 50A with a hammer or the like, and a method of mechanically pushing the rivet 50A downward in FIG. However, when the rivet 50A is pushed out, it is necessary to accept the reaction force of the force for pushing the rivet 50A (the force acting upward in FIG. 7), so that the pushing device is held against the joining base material. Had to be installed as. As a result, there has been a problem that the size of the entire extrusion apparatus becomes large.

  On the other hand, according to the rivet removal method of the present embodiment, the rivet 50A is pulled out, so that the rotary pulling device 80 has a reaction force (force acting downward in FIG. 10) of pulling out the rivet 50A. Works. Then, as shown in FIG. 10, the rotary pulling device 80 is attached so as to be in contact with the surface of the flat portion 11 of the joint member 10, so that the reaction force described above is received on the surface of the flat portion 11 of the joint member 10. Will be. As a result, the rotary pulling device 80 does not need to be attached so as to be held with respect to the bonding base material, can be configured compactly, and is advantageous in terms of space when working.

As mentioned above, although embodiment of the rivet removal method concerning this invention was described, this invention is not limited to this, A various change is possible in the range which does not deviate from the meaning.
For example, as shown in FIG. 9, in this embodiment, the diameter-expanded portion 70b of the pin 70 is formed in a tapered shape. However, as shown in FIG. 12, the diameter-expanded portion 70d of the pin 70 is a step portion between the shaft portion 70a and the large-diameter portion 70c, and may engage with the end surface 50d of the rivet 50A.

In the present embodiment, the heads 50b and 50c at both ends of the rivet 50A are removed in the head removing step. However, of the heads 50b and 50c at both ends of the rivet 50A, the head 50b on one end (the insertion side of the pin 70) may be removed, and the head 50c on the other end may not be removed.
In addition, the length (100 mm) of the rivet 50A, the diameter (22 mm) of the shaft portion 50a of the rivet 50A, and the diameter (18 mm) of the through hole 50f of the present embodiment are not limited to the above-described numerical values, and may be changed as appropriate. Is possible.

DESCRIPTION OF SYMBOLS 1 Attachment part 10 Joint member 11 Flat part 20 Attachment plate 30 Thickening board 40 Standing member 41 Flange part 50A Rivet 50a Shaft part 50b, 50c Head part 50d, 50e End surface 50f Through-hole 60 High-strength bolt 70 Pin 70a Shaft part 70a1 Threaded portion 70b Expanded portion 70c Large diameter portion 70d Expanded portion 80 Rotating pulling device RA Rivet hole

Claims (3)

In the rivet removal method of removing a rivet that joins multiple steel plates that overlap in a large steel structure,
A head removing step of removing at least one of the heads at both ends of the rivet;
A through hole forming step for forming a through hole coaxial with the rivet and having a diameter smaller than the diameter of the shaft portion of the rivet;
A pin shaft is inserted into the through-hole from one end of the rivet, and a pin having a larger diameter than that of the pin is engaged with an end surface formed on one end of the rivet. Insertion process;
A rivet removing method comprising: a pin pulling step for removing the rivet by pulling out the shaft portion of the pin protruding from the through hole to the other end side of the rivet. The rivet removal method according to claim 1, wherein
In the pin pulling step, the shaft portion of the pin is pulled out without rotating a screw portion formed on the shaft portion of the pin using a rotary pulling device. In the rivet removing method according to claim 1 or 2,
In the pin insertion step, the rivet removing method is characterized in that an enlarged portion of the pin formed in a tapered shape is engaged with an end surface of the rivet.

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