Bolt punching tool and bolt punching method using the same

Abstract

To provide a bolt punching jig and a bolt punching method that enable easy and safe removal of a bolt which sticks to or bite into a bolt hole of a work-piece.SOLUTION: A bolt punching jig comprises: a stem; a connection part extending from the stem; a suppressing plate part which is connected to a tip of the connection part; a first bolt hole and a second bolt hole which penetrate the suppressing plate part; and a jack installation space which is provided between the stem and the first bolt hole. By use of the bolt punching jig, a nut is removed from a punching object bolt and a bolt adjacent to the same, the punching object bolt is caused to penetrate the first bolt hole and the adjacent bolt is caused to penetrate the second bolt hole, the nut is re-screwed and tightened to the adjacent bolt to fix the suppressing plate part to a work-piece, a jack is located between a tip of the punching object bolt and the stem and is operated, thereby punching the punching object bolt from the work-piece.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a jig and method for removing a bolt secured in a bolt hole, in particular, a joint bolt secured in a bolt hole of a shaft joint. [Background technology]

[0002] Various couplings are used as mechanical components that connect the input drive shaft of an electric motor or the like to the output driven shaft of a reducer, motor, or the like to transmit power. One such coupling is a flexible shaft coupling, an example of which is disclosed in, for example, Japanese Utility Model Laid-Open Publication No. 4-95130. Flexible shaft couplings provide flexibility to the shaft coupling, allowing for misalignment between the two shafts and reducing problems caused by misalignment, such as uneven wear of the bearings that rotatably support the two shafts and vibration of the device.

[0003] FIG. 3 shows an example of a flange-type flexible shaft joint that is generally used as a flexible shaft joint. The flexible shaft joint 1 includes a flange 2 on the drive shaft side and a flange 3 on the driven shaft side. A plurality of joint bolts 4 are fitted into bolt holes (not shown) provided at a plurality of positions in the circumferential direction of the flanges 2 and 3, and these joint bolts 4 penetrate the flanges 2 and 3 in the axial direction of the flexible shaft joint 1. The joint bolts 4 are fitted into the bolt holes of one of the flanges 2 via bushes (not shown) made of elastomer such as rubber. A washer 5 is fitted into the portion of the joint bolt 4 that protrudes from the flange 2 and is adjacent to the head of the joint bolt 4. A nut 6 is screwed onto the portion of the joint bolt 4 that protrudes from the other flange 3. The flanges 2 and 3 are fixed by tightening the nut 6, and the power of one flange 2 can be transmitted to the other flange 3. The relative torque fluctuation of the flanges 2 and 3 is absorbed by the bushes.

[0004] In applications where a flexible shaft coupling needs to transmit excessive power, a tapered coupling bolt may be used as the coupling bolt. The coupling bolts and bushes used to connect the flexible shaft coupling are consumables and must be replaced when they deteriorate or break. However, particularly when a tapered coupling bolt is used, the coupling bolt may become stuck or even bite into the bolt holes of the flanges 2 and 3 after many years of use, making it difficult to remove the bolt.

[0005] Conventionally, when replacing a joint bolt, the nut was removed from the joint bolt and the tip of the joint bolt was struck with an impact tool such as a hammer to remove the joint bolt from the bolt hole in the flange of the flexible shaft joint. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Utility Model Application Publication No. 4-95130 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the removal of a joint bolt by striking with an impact tool such as a hammer takes time and effort, and requires the use of excessive force, which increases the risk of injury to the worker due to incorrect operation, and, when working at height, the risk of accidentally dropping the impact tool or joint bolt from a high place.

[0008] In view of the above-mentioned problems, the present invention aims to provide a jig and method that enables removal of a joint bolt fixed to a bolt hole of a flange from a shaft joint with little time and effort, while preventing risks such as injury or the need for an impact tool or the dropping of the joint bolt. [Means for solving the problem]

[0009] A bolt punch-out jig according to one aspect of the present invention includes a base having a base surface, a connecting portion extending perpendicularly from the base surface to the base surface, a pressing plate portion connected to a tip end of the connecting portion and having an inner surface facing the base surface, a first bolt hole provided at a position facing at least a portion of the base surface and penetrating the pressing plate portion, and a front bolt provided at a position separated from the first bolt hole. Note It is characterized by having a second bolt hole that penetrates the retaining plate portion, and a jack installation space that is surrounded by the base surface, the connecting portion, and the inner surface and is provided in a portion that aligns with the first bolt hole.

[0010] It is preferable that two second bolt holes are provided on either side of the first bolt hole, and that the first bolt hole and the two second bolt holes are arranged at a predetermined interval so that the centers of each hole are on the same circumference of an imaginary circle having a predetermined center.

[0011] The distance between the first bolt hole and the second bolt hole is set to be the same as or close to the distance between two adjacent bolt holes in the flange of the applicable joint bolt.

[0012] The bolt punching method according to one embodiment of the present invention uses the bolt punching jig according to the present invention. (1) In a workpiece fastened by a plurality of bolts and nuts at a predetermined interval, the nuts of a bolt to be punched and a bolt adjacent to the bolt to be punched are removed, (2) placing the retaining plate portion on the workpiece in a state in which the bolt to be punched is inserted through the first bolt hole and the adjacent bolt is inserted through the second bolt hole; (3) The nut is re-threaded onto the adjacent bolt and tightened to fix the retaining plate portion to the workpiece; (4) The above For bolt removal A jack is placed between a tip end of the bolt to be punched protruding from the first bolt hole and the base surface of the base in a jack installation space of the jig; (5) The jack is operated between the tip of the bolt to be pushed out and the base surface in a direction in which they move away from each other, thereby pushing out the bolt to be pushed out from the workpiece. The present invention is characterized by comprising the steps of:

[0013] The present invention is preferably applied when the workpiece is a shaft coupling and the bolt is a coupling bolt. Effect of the Invention

[0014] For punching out bolts according to one embodiment of the present invention Osamu Tool and bolt using the same Push By applying the extraction method, in a workpiece fastened with a number of bolts and nuts at a given interval, it becomes possible to properly push out and remove a bolt that has become stuck to the workpiece, particularly a bolt that has become wedged in a bolt hole of the workpiece, without requiring excessive force, from the workpiece, thereby shortening the time required for removing the bolt from the workpiece and improving the safety of the operation. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1(a) is a plan view of a bolt-pushing jig according to one embodiment of the present invention, FIG. 1(b) is a front view of the bolt-pushing jig, and FIG. 1(c) is a bottom view of the bolt-pushing jig. [Diagram 2] FIG. 2 is a schematic diagram showing a state in which the bolt punch-out jig is attached to a workpiece and a jack is placed in the jack installation space. [Diagram 3] FIG. 3 is a perspective view showing an example of a flange-type flexible joint, which is an example of a workpiece to which the present invention is applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, a bolt punch-out jig and a bolt punch-out method using this bolt punch-out jig according to one embodiment of the present invention will be described with reference to Figs. 1 and 2.

[0017] Although the present invention can be applied to any workpiece (workpiece) in which a plurality of members are connected in the axial direction of the bolts by fastening with a plurality of bolts and nuts at a predetermined interval, the present invention is particularly suitable for a shaft coupling such as a flange-type flexible shaft coupling in which a joint bolt passes through a bolt hole arranged at a predetermined interval in the circumferential direction of two flanges and the two flanges are fixed by tightening a nut screwed onto the tip of the joint bolt. In the following explanation, a flange-type flexible shaft coupling and a joint bolt are used as examples of the workpiece and bolts, but the present invention is not limited thereto.

[0018] A bolt push-out jig 7 according to one embodiment of the present invention comprises a pressing plate portion 8, a connecting portion 9, and a base portion 10. Of these, the pressing plate portion 8 has a function of being pressed by a nut 6 against the outer surface of the flange of a flexible joint 1, which is a workpiece, when a joint bolt 4 is pushed out. The connecting portion 9 is a member for connecting and fixing the pressing plate portion 8 and the base portion 10 in the axial direction of the flexible joint 1. The base portion 10 faces the pressing plate portion 8 and is a member having a base surface 18 with which a part of a jack 19 abuts during use.

[0019] The connecting portion 9 extends perpendicularly from the base 10 to the base surface 18 and the inner surface of the retaining plate portion 8, with its base end connected to the base 10 and its tip end connected to the retaining plate portion 8. The inner surface of the retaining plate portion 8 faces the base surface 18 of the base 10. All of the members constituting these are made of steel, including stainless steel, other metals with sufficient strength, or other materials. These members need to be made of a material strong enough not to be deformed or damaged by a force that tries to spread apart the base surface of the base 10 and the inner surface of the retaining plate portion 8, at least by a jack, including a hydraulic jack, or the like.

[0020] The retaining plate portion 8 is provided at a position at which at least a portion faces the base surface 18 of the base portion 10, and is provided with a first bolt hole 11 penetrating the retaining plate portion 8, and a second bolt hole 12 provided at a position spaced apart from the first bolt hole 11 and penetrating the retaining plate portion 8. At least one second bolt hole 12 needs to be provided, but preferably two second bolt holes 12 are provided on either side of the first bolt hole 11.

[0021] In the illustrated example, the first bolt hole 11 and the two second bolt holes 12 are arranged at a predetermined interval so that the center of the first bolt hole 11 and the center of the second bolt hole 12 are on the same circumference of a virtual circle with a predetermined center.

[0022] Basically, the arrangement of the first bolt hole 11 and the second bolt hole 12 is appropriately determined according to the work (workpiece) to which the bolt punching jig of this example is applied, and in this example, the arrangement of the bolt holes (joint bolts) provided in the flange of the flexible shaft joint. Therefore, basically, the bolt punching jig of this example needs to be prepared according to the size of the flexible shaft joint to be applied and the arrangement of the bolt holes (joint bolts). However, it is not necessary to completely match the size and bolt hole arrangement of a specific flexible shaft joint, and it is possible to correspond to the size and bolt hole arrangement of several types of flexible shaft joints by appropriately increasing the diameter of each of the first bolt hole 11 and the second bolt hole 12 and approximating the arrangement interval of each to the arrangement of the bolt holes in several types of flexible shaft joints.

[0023] Furthermore, in addition to workpieces such as shaft couplings in which the bolt holes of the coupling bolts (coupling bolts) are arranged circumferentially, the bolt push-out method using the bolt push-out jig of this example can also be applied to cases in which a number of bolt holes are arranged at predetermined intervals, for example in a straight line, and tapered bolts or the like are fitted into these bolt holes and have become stuck after long-term use.

[0024] In the bolt punching jig 7 of this example, the holding plate portion 8 is composed of a plate-like member having a predetermined thickness (vertical length in FIG. 1(b)) in a sectoral shape in plan view. However, it is possible to use a plate-like member of any shape in which two or three bolt holes can be appropriately arranged, such as a rectangular or semicircular plate-like member. The length (horizontal length in FIG. 1) and width (vertical length in FIG. 1(a)) of the holding plate portion 8 are set to appropriate sizes depending on the size of the flexible shaft joint and other workpieces, the interval between adjacent bolt holes (fitting bolts), the number of second bolt holes 12, and the like. The appropriate size and shape are set so that at least deformation such as bending does not occur when pressed with a hydraulic jack, or the periphery of the first bolt hole 11 and the second bolt hole 12 is not damaged. The thickness of the retaining plate portion 8 must be a thickness that has the strength to withstand the force of the hydraulic jack 19 pressing against its inner surface and the force that tries to bend the retaining plate portion 8 through the legs 13, depending on the material of the member to which it is applied, but at the same time, it must be shorter than the length of the tip of the bolt 4 protruding from the flange surface of the flexible shaft coupling 1, etc. Therefore, from these viewpoints, the thickness of the retaining plate portion 8 is appropriately regulated.

[0025] The sizes of the first bolt hole 11 and the second bolt hole 12 are set to be larger than the outer diameter of the tip of the bolt 4 of the applicable workpiece (the diameter of the circumscribing circle of the thread) and smaller than the outer diameter of the nut 6 so that the retaining plate portion 8 is sufficiently fixed when the nut 6 is re-threaded and fastened onto the bolt 4.

[0026] In this embodiment, the bolt removal jig 7 is 18 A jack installation space S is provided in a portion surrounded by the inner surface of connecting portion 9 and the inner surface of retaining plate portion 8 and aligned with first bolt hole 11. Therefore, connecting portion 9 of bolt punch-out jig 7 in this example is composed of two legs 13 provided on both sides of base portion 10 in the extension direction (left and right direction in FIG. 1).

[0027] More specifically, in the bolt-pullout jig 7 of this example, the base 10 and the connecting portion 9 are formed by an approximately U-shaped frame 14, and this approximately U-shaped frame 14 is formed by a rectangular base 10 and two legs 13 extending vertically from the base surface 18 at both ends of the base.

[0028] The substantially U-shaped frame 14 is composed of rectangular plate-like members having a predetermined overall thickness, and the thickness and width of the base 10 are set according to the material of the member to be used, so that the thickness (length in the vertical direction in FIG. 1(b)) and width (length in the vertical direction in FIG. 1(c)) have a strength sufficient to withstand the force of a hydraulic jack 19 pressing against the base surface. The legs 13 need to have a thickness (length in the horizontal direction in FIG. 1(b)) and width (length in the vertical direction in FIG. 1(c)) that are strong enough to withstand the force exerted in the extension direction when the hydraulic jack 19 presses against the inner surface of the retaining plate 8 and the base surface 18 of the base 10 so as to spread them apart. In addition, unlike the clamping plate portion 8 which is fixed to the flange of the flexible shaft coupling 1 during use, the approximately U-shaped frame 14 receives the force of the hydraulic jack 19 alone during use. Therefore, if it is made of a similar material, its thickness should be greater than that of the clamping plate portion 8; for example, it is preferable to make the thickness of the clamping plate portion 8 plus a thickness that is approximately 0.5 to 1.0 times the thickness of the flange of the flexible shaft coupling 1, or approximately 1.2 to 2.0 times the thickness of the clamping plate portion 8.

[0029] The bolt removal jig 7 of this embodiment further comprises a substantially U-shaped frame consisting of a base 10 and legs 13. 14 In order to reinforce the strength of the base 10 and the connecting portion 9 which are basically constructed as above, and to reinforce the strength of the pressing plate portion 8, the apparatus is provided with a crosspiece member 15, a side support member 16, and a rear support member 17.

[0030] The crosspiece 15 is made of a substantially U-shaped plate-like member, similar to the substantially U-shaped frame 14, and is made up of a horizontal crosspiece extending laterally (left-right direction in FIG. 1) along the back surface of the base 10, and a vertical crosspiece extending vertically (up-down direction in FIG. 1(b)) along the back surface of the leg 13. In the illustrated example, the horizontal crosspiece of the crosspiece 15 has a width (length in the vertical direction in FIG. 1(b)) approximately equal to the thickness of the base 10, and a length such that both ends protrude from both sides of the base 10. The vertical crosspiece of the crosspiece 15 has a length equal to the length of the leg 13, and a width (length in the horizontal direction in FIG. 1(b)) greater than the thickness of the leg 13. The crosspiece 15 is joined to the back surface of the substantially U-shaped frame 14. The crosspiece 15 has a function of reinforcing the strength of the substantially U-shaped frame 14 and reinforcing the welded parts. From this viewpoint, the thickness of the crosspiece member 15 (the length in the vertical direction in FIG. 1(c)) can be smaller than the thickness of the approximately U-shaped frame 14 and similar to the thickness of the retaining plate portion 8. The upper ends of the vertical crosspiece members of the crosspiece member 15 are joined to the inner surface of the rear end of the longitudinal middle portion of the retaining plate portion 8.

[0031] The side support members 16 are made of rectangular plate-like members, and are provided at both ends of the pressing plate portion 8 in the length direction (left and right direction in FIG. 1) so as to extend vertically from the inner surface of the pressing plate portion 8. The rear support members 17 are also made of rectangular plate-like members, and are provided at the rear end of the pressing plate portion 8 near both ends in the length direction, and at both sides of the crosspiece member 15 so as to extend vertically from the inner surface of the pressing plate portion 8. The side support members 16 and the rear support member 17 have a function of reinforcing the strength of the pressing plate portion 8 so that the pressing plate portion 8 is not deformed, such as bent, by the force of the hydraulic jack 19 during use. From this viewpoint, the width (length in the vertical direction in FIG. 1(b)) and thickness of these members are appropriately set. As long as the above-mentioned function can be ensured, it is preferable to make the thickness of these members smaller than that of the crosspiece member 15 (about 0.2 to 0.5 times the thickness of the crosspiece member 15) from the viewpoint of preventing an increase in the weight of the entire jig.

[0032] The bolt push-out jig 7 of this example may have any specific configuration as long as it basically comprises the holding plate portion 8, the connecting portion 9, and the base portion 10. Therefore, the crosspiece members 15, the side support members 16, and the rear support members 17 may be omitted if the strength of the holding plate portion 8 and the approximately U-shaped frame 14 constituting the connecting portion 9 and the base portion 10 can be sufficiently ensured.

[0033] The means for manufacturing the bolt punching jig 7 of this example is also arbitrary. The bolt punching jig 7 of this example can be formed by any arbitrary and various processing means, such as integrally molding the bolt punching jig 7 by casting or the like, manufacturing each member separately and joining them to each other by welding, or forming some or a plurality of members by bending processing using a press.

[0034] A bolt punching method according to an embodiment of the present invention uses the bolt punching jig according to the embodiment of the present invention described above, and includes the following steps. Note that the following description is an example in which the bolt punching jig having the configuration shown in FIG.

[0035] (1) In a workpiece that is fastened by a number of bolts and nuts spaced at a specified interval, the nuts that are threadedly attached to the bolt to be punched and the bolt adjacent to the bolt to be punched are removed.

[0036] In the flexible shaft coupling 1 of Fig. 3, the nuts 6 screwed onto the tips of the coupling bolts 4 on the flange 3 side are removed. In this case, the nuts 6 are removed from at least the coupling bolt 4 to be punched out and the two coupling bolts 4 adjacent thereto in the circumferential direction.

[0037] (2) The bolt to be punched is passed through the first bolt hole and the adjacent bolt is passed through the second bolt hole, and the retaining plate is placed on the workpiece.

[0038] 2, the vertical direction of the pressing plate portion 8 and base portion 10 of the bolt pressing jig 7 is reversed from the state shown in FIG. 1(b), and the pressing plate portion 8 is placed against the flange surface of the flange 3 of the flexible joint 1, with the tip portion of the joint bolt 4 to be pressed through the first bolt hole 11 and the tip portions of two adjacent joint bolts 4 passing through the second bolt hole 12. In this state, the tip portions of the joint bolts 4 protrude upward from the first bolt hole 11 and the second bolt hole 12.

[0039] (3) The retaining plate is fixed to the workpiece by re-threading and tightening the nut onto the adjacent bolt.

[0040] The nut 6 that was once removed is screwed again onto the tip of the joint bolt 4 protruding from the second bolt hole 12 out of the joint bolts 4 protruding from the first bolt hole 11 and the second bolt hole 12. By further tightening the nut 6, the retaining plate portion 8 is fixed in close contact with the flange surface of the flange 3 of the flexible joint 1.

[0041] (4) In the jack installation space of the bolt punch-out jig, a jack is placed between the tip of the bolt to be punched out protruding from the first bolt hole and the base surface of the base part.

[0042] With the bolt push-out jig 7 placed on the flange 3, the joint bolt 4 to be pushed out protrudes inward from the inner surface of the retaining plate 8 in the jack installation space S surrounded by the inner surface of the retaining plate 8, the leg 13 of the connecting part 9 (U-shaped frame 14), and the base surface 18 of the base 10. A hydraulic jack 19 is inserted between the tip end (tip end surface) of the joint bolt 4 and the base surface 18 of the base 10 in this jack installation space S.

[0043] As the hydraulic jack 19, various types of known hydraulic jacks such as a pantograph jack and a cylinder type jack can be applied. Depending on the structure of the hydraulic jack and its size relative to the bolt punching jig 7, the entire jack can be placed in the jack installation space S, or only the movable part of the jack, or only the body and the claw part of the ram can be placed. In addition to the hydraulic jack, depending on the size of the shaft coupling or other workpiece to be applied and the structure and size of the bolt punching jig 7 corresponding thereto, mechanical jacks such as a screw jack, or air-operated jacks such as an air jack can also be applied.

[0044] (5) The jack is operated between the tip (tip surface) of the bolt to be pushed out and the base surface of the base in a direction that moves the tip surface and the base surface away from each other, thereby pushing the bolt out of the workpiece.

[0045] A hydraulic jack 19 is operated between the base surface 18 of the base 10 of the bolt push-out jig 7 and the tip (tip surface) of the joint bolt 4 to be pushed out, to apply a force in a direction in which the base 10 and the joint bolt 4 move away from each other (the up and down direction in FIG. 2 ). Since the base 10 is fixed to the flange 3 via the connecting portion 9 and the retaining plate portion 8, the hydraulic jack 19 acts to press the joint bolt 4 downward. This makes it possible to easily push out the joint bolt 4 even if the joint bolt 4 is a tapered bolt and is fixed or wedged into the bolt holes of the flanges 2 and 3.

[0046] After the punching operation for the bolt 4 to be punched out is completed, the nut 6 screwed onto the tip of the adjacent joint bolt 4 is removed to separate the bolt punching jig 7 from the flange surface of the flange 3, and a new bolt together with a new bush is attached to the flange hole of the flanges 2, 3, and the nut 6 is screwed and tightened to complete the replacement operation for one joint bolt 4. By sequentially repeating the same operation for all the joint bolts 4, the replacement (update) operation of the joint bolts 4 and bushes for the flexible shaft joint 1 is completed.

[0047] The bolt punching jig 7 of the present invention and the bolt punching method using the same are preferably applied when the workpiece is a shaft joint such as a flexible shaft joint, and the bolt is a joint bolt consisting of a tapered bolt. However, the present invention can also be widely applied to a flange-type pipe joint fastened with multiple bolts and nuts arranged in the circumferential direction, or to any workpiece fastened with multiple continuous bolts and nuts arranged in a linear direction, and to joint bolts that are not tapered. [Explanation of symbols]

[0048] 1 Workpiece (flexible shaft coupling) 2 Drive side flange 3 Driven side flange 4 Joint bolts 5 Washer 6 Nuts 7 Bolt removal tool 8 Retaining plate 9 Connecting part 10 base 11 First bolt hole 12 Second bolt hole 13 Legs 14. U-shaped frame 15 Crosspieces 16 Side support member 17 Rear support member 18 Base 19 Hydraulic jack

Claims

1. A bolt punching jig for enabling a bolt to be removed by a jack from among a plurality of bolts fixed in bolt holes of a workpiece, comprising: a base having a base surface; A connecting portion extending from the base portion perpendicular to the base surface; A pressing plate portion connected to a tip end of the connecting portion and having an inner surface facing the base surface; A first bolt hole for passing the bolt to be punched, the first bolt hole being provided at a position at least partially facing the base surface and penetrating the retaining plate portion; at least one second bolt hole, which is adjacent to the bolt to be punched out among the plurality of bolts when the bolt to be punched out is passing through the first bolt hole, and which is a bolt hole for passing a bolt used to fix the holding plate portion to the workpiece when the bolt to be punched out is pushed out, the second bolt hole being provided at a position spaced apart from the first bolt hole and passing through the holding plate portion; a jack installation space that is surrounded by the base surface, the connecting portion, and the inner surface, that is provided in a portion that aligns with the first bolt hole, that is disposed between the tip end of the bolt to be punched and the base surface when the bolt to be punched passes through the first bolt hole, and that enables the installation of a jack that can operate in a direction that separates the tip end of the bolt to be punched from the base surface; A bolt removal jig comprising:

2. This is applicable when removing the bolts fixed to a workpiece in which the bolt holes are arranged at predetermined intervals in the circumferential direction, 2. The bolt punch-out jig according to claim 1, wherein the second bolt hole is provided in pairs on either side of the first bolt hole, and the first bolt hole and the two second bolt holes are arranged at a predetermined interval so that the centers of the respective holes are on the same circumference of an imaginary circle having a predetermined center.

3. Using the bolt punching jig according to claim 1 or 2, (1) In a workpiece fastened by a plurality of bolts and nuts at a predetermined interval, the nuts screwed in the bolt to be punched and the bolt adjacent to the bolt to be punched are removed, (2) The bolt to be punched is inserted through the first bolt hole and the adjacent bolt is inserted through the second bolt hole. In this state, the pressing plate is placed on the workpiece. (3) The nut is re-threaded onto the adjacent bolt and tightened to fix the holding plate portion to the workpiece; (4) In a jack installation space of the bolt punch-out jig, a jack is disposed between a tip end of the bolt to be punched protruding from the first bolt hole and the base surface of the base part; (5) The jack is operated between the tip of the bolt to be punched and the base surface in a direction in which they move away from each other, thereby punching out the bolt to be punched from the workpiece. A bolt punching method comprising the steps of:

4. The bolt punching method according to claim 3, wherein the workpiece is a shaft coupling, and the bolt is a coupling bolt.

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