Punching and enlarging tools

Abstract

To easily exchange a diameter expansion blade body forming a diameter expansion hole part with a simple structure.SOLUTION: A punching diameter expansion tool 1 comprises: a front part 21 with a shape and a size corresponding to a straight hole; a rear part 22 formed with a long hole 221 extending to an axial direction; a cylinder 2 having a flange-like stopper 23 with a large diameter between the front part 21 and the rear part 22 and formed with a longitudinal slit 212 at the front part 21; an exterior body 3 formed with a storage recessed part 311 interpolated with a shank j323 at the rear side and the rear part 22 at the front side; a compression spring 4 energizing the cylinder 2 forward with respect to the exterior body 3; and a diameter expansion blade body 5 provided with a tilted diameter expansion blade 52 freely in and out with respect to the longitudinal slit 212. The exterior body 3 and the diameter expansion blade body 5 are pivoted by a detachable fixation pin 6 inserted into the long hole 221 of the cylinder 2, and a tilt mechanism tilting the diameter expansion blade body 5 so that the diameter expansion blade 52 projects from the longitudinal slit 212 to the outside in accordance with the relatively forward movement of the fixation pin 6 with respect to the long hole 221 is provided.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a drilling and expanding tool used, for example, when forming an enlarged hole portion in a drilled hole in concrete. [Background technology]

[0002] Conventionally, when attaching an object to an existing concrete structure, post-installed anchors have been used, such as mechanical anchors in which an expansion sleeve is expanded in a straight drilled hole in the concrete and pressed against the hole wall to mechanically fix the object, and adhesive anchors in which a hardening adhesive is poured into a drilled hole in the concrete together with a bolt and hardened. The post-installed anchor is cast into the concrete, and the object is attached to the concrete structure via the post-installed anchor.

[0003] If the concrete into which the post-installed anchor is cast is weak, there is a concern that the post-installed anchor will not be able to be sufficiently anchored after casting. Conversely, if the concrete into which the post-installed anchor is cast is high-strength concrete, there is a concern that the enlarged diameter portion of the mechanically anchored anchor will not open sufficiently and will not be able to bite into the hole wall, or that the frictional force will be insufficient, resulting in insufficient anchoring power. To eliminate such concerns, a method is used in which the diameter of a straight drilled hole formed in concrete is enlarged near the bottom of the hole to form an enlarged diameter hole portion, and the mechanically anchored anchor is used to open the expansion sleeve at the enlarged diameter portion, thereby increasing the anchoring power of the mechanically anchored anchor.

[0004] A hole having this enlarged diameter portion can be formed, for example, by using the drilling device of Patent Document 1. This drilling device comprises a cylindrical sleeve attached to the front of the body so as to be movable within a predetermined range in the front-rear direction and having a contact portion at its front end that contacts the concrete surface, a first compression spring that urges the cylindrical sleeve forward relative to the body, a drill blade that is provided at its tip for drilling a straight hole and has a base end inserted into the body and is attached to the cylindrical sleeve so as to be movable in the front-rear direction, and a cutting blade that is fixed to the tip and is attached to the side of the drill blade body so as to be movable in the front-rear direction and moves forward on the side of the drill blade body. The drill bit body has an enlarged diameter hole cutting member whose cutting blade sometimes protrudes sideways, a second compression spring which urges the enlarged diameter hole cutting member rearward relative to the drill bit body, and a cam which is rotatably supported on the main body and has one abutment portion abutting against the inner wall of the cylindrical sleeve and the other abutment portion abutting against the base end of the enlarged diameter hole cutting member.When the main body moves forward relative to the cylindrical sleeve, the cam rotates to move the enlarged diameter hole cutting member forward, and the cutting blade which forms the enlarged diameter hole protrudes sideways. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5806782 Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, the drilling device of Patent Document 1 has the advantage of being able to form a straight hole and an enlarged hole section in a single drilling operation in concrete, but because the structure of the device is very complicated, if the cutting blade that forms the enlarged hole section is damaged, it is difficult to replace the enlarged hole section cutting member to which the cutting blade is fixed on site. Therefore, if the cutting blade that forms the enlarged hole section is damaged, it is necessary to quickly prepare another drilling device or to prepare a spare drilling device in advance in case of damage to the cutting blade, which results in problems such as reduced efficiency of the drilling operation and increased construction costs.

[0007] The present invention has been proposed in consideration of the above-mentioned problems, and aims to provide a drilling and expansion tool that has a simple structure, allows the expansion blade body that forms the enlarged hole portion to be easily replaced, and can improve the efficiency of drilling work and reduce construction costs. [Means for solving the problem]

[0008] The hole-expanding tool of the present invention comprises: A drilling and expanding tool for forming an expanded hole portion in a straight hole already formed in a workpiece, the tool having a front end closed and an outer shape The shape and size of the straight hole to be drilled in the workpiece A cylindrical The front part and the long hole extending in the axial direction were formed. Cylindrical a rear portion, and a portion disposed between the front portion and the rear portion and having a diameter larger than both the front portion and the rear portion; Circular It has a flange-shaped stopper, and a vertical slit extending in the axial direction is formed in the front part. Approximately cylindrical The tool comprises a cylinder, an outer casing having a shank at the rear side and an approximately bottomed cylindrical storage recess at the front side into which the rear part of the cylinder is inserted, a compression spring provided at the rear part of the cylinder and biasing the cylinder forward relative to the outer casing, and an expanding blade body extending in the axial direction of the cylinder and housed within the cylinder, having an inclined expanding blade formed at its front end, the expanding blade being arranged so as to be able to freely enter and exit the vertical slit, the tool being characterized in that the outer casing and the expanding blade body are journalled by a removable fixing pin that is inserted into the long hole of the cylinder, and a tilting mechanism is provided that tilts the expanding blade body so that the expanding blade protrudes outward from the vertical slit in response to the relative forward movement of the fixing pin with respect to the long hole. According to this, the tool for forming the enlarged hole portion can be made simple in structure, and when the enlarged hole portion is broken or deteriorated, the removable fixing pin can be removed and disassembled on-site, and the enlarged hole portion forming blade body can be easily replaced, which can improve the efficiency of the drilling work and reduce the construction cost. In addition, the restoring force of the compression spring allows the enlarged hole portion protruding outward from the vertical slit to be smoothly restored to its original position after the work of forming the enlarged hole portion. In addition, by forming a vertical slit extending in the axial direction in the front part of the shape and size corresponding to the straight hole, it is possible to prevent the chips of concrete, etc. from clogging between the enlarged hole portion and the cylinder when forming the enlarged hole portion. In addition, the flange-shaped stopper can prevent the chips from entering the exterior body when forming the enlarged hole portion. In addition, by providing the flange-shaped stopper and the vertical slit in front of the flange-shaped stopper, it is possible to easily clean the chips attached to the tool after the work of forming the enlarged hole portion.

[0009] In the hole-boring and expanding tool of the present invention, the tilting mechanism is The cylinder has an axially extending base of the expanding blade body, and the base is formed on the front side of the expanding blade body so as to be inclined from the longitudinal direction of the base. The expansion blade is characterized in that it is composed of another long hole formed in the expansion blade extending in the inclined direction of the expansion blade, and an eccentric pin that is detachably provided at the front end of the cylinder and inserted into the another long hole. According to this, when the expanding blade is damaged or deteriorated, the detachable fixing pin and eccentric pin can be removed and disassembled on-site, and the expanding blade body that forms the expanding hole can be replaced more easily. Also, the operation of inserting and removing the expanding blade through the vertical slit can be performed accurately and stably with a simpler structure.

[0010] The piercing and expanding tool of the present invention is characterized in that a vertical groove extending in the axial direction is formed on the outer peripheral surface of the front part of the cylinder at a circumferential position different from that of the vertical slit. This makes it possible to introduce chips of concrete and the like generated during the work of forming the enlarged diameter hole portion into the vertical groove, thereby more reliably preventing the chips from clogging the gap between the enlarged diameter blade body and the cylinder. Effect of the Invention

[0011] The hole-drilling and expanding tool of the present invention has a simple structure and allows the expanding blade that forms the enlarged hole portion to be easily replaced, thereby making it possible to increase the efficiency of the hole-drilling work and reduce construction costs. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2A is a front view of a hole-punching and expanding tool according to an embodiment of the present invention, and FIG. 2B is an explanatory diagram for explaining assembly of the hole-punching and expanding tool according to the embodiment. [Diagram 2] 4A is a front view of an attachment in the drilling and expanding tool of the embodiment, and FIG. [Diagram 3] 1A is a front view of a coupling in a drilling and expanding tool according to an embodiment, and FIG. [Figure 4] 1A is a bottom view of a cylinder in a drilling and expanding tool according to an embodiment, FIG. 1B is a front view thereof, FIG. 1C is a cross-sectional view taken along line AA in FIG. 1B, FIG. 1D is a cross-sectional view taken along line BB in FIG. 1B, and FIG. 1E is a cross-sectional view taken along line CC in FIG. [Diagram 5] 4A is a cross-sectional view showing a state when the hole-punching and expanding tool of the embodiment is inserted into a straight hole, and FIG. 4B is a cross-sectional view showing a state when the hole-punching and expanding tool of the embodiment is forming an enlarged hole portion. [Figure 6] 5(a) to 5(d) are process explanatory views illustrating a process of forming a hole having an enlarged diameter hole portion by the hole-boring and enlarging tool of the embodiment. [Figure 7] FIG. 1A is an explanatory diagram showing a state in which a mechanically-fixed anchor is fixed in a drilled hole having an enlarged diameter hole portion, and FIG. 1B is an explanatory diagram showing a state in which an adhesive-type anchor is fixed in a drilled hole having an enlarged diameter hole portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] [Embodiment of the drilling and expanding tool] 1 to 5, a drilling and expanding tool 1 according to an embodiment of the present invention has a substantially cylindrical cylinder 2, an exterior body 3, a compression spring 4, and a diameter expansion blade body 5. The cylinder 2 is composed of a front portion 21, a rear portion 22, and a flange-shaped stopper 23 provided between the front portion 21 and the rear portion 22.

[0014] The front part 21 is formed in a shape and size corresponding to the straight hole 101 to be drilled in the object to be drilled, such as concrete 100, and the front end is closed, and a pin hole 211 for inserting an eccentric pin is formed so as to penetrate the internal space near the front end in a direction perpendicular to the axial direction. A vertical slit 212 extending in the axial direction is formed in the front part 21, and the vertical slit 212 is formed so as to extend from the closed part of the front end to the flange-shaped stopper 23. In addition, a vertical groove 213 extending in the axial direction is formed on the outer circumferential surface of the front part 21 at a position different in the circumferential direction from the vertical slit 212, and in the illustrated example, the vertical groove 213 is formed at a position opposite in the circumferential direction to the vertical slit 212. Note that the vertical groove 213 may be formed at a plurality of different positions.

[0015] In this example, the rear portion 22 is formed in a cylindrical shape with an outer diameter smaller than that of the front portion 21, and an elongated hole 221 extending in the axial direction is formed at a position near the rear end. In addition, a brim-shaped stopper 23 between the front portion 21 and the rear portion 22 is formed with a diameter larger than both the front portion 21 and the rear portion 22. The brim-shaped stopper 23 restricts the forward movement of the exterior body 3 when the exterior body 3 described below moves forward, and has a diameter larger than the straight hole 101 of a size corresponding to the front portion 21, so that it abuts against the mouth of the straight hole 101.

[0016] The outer casing 3 has a shank 323 at the rear for connecting to a rotary drive tool, and a substantially bottomed cylindrical accommodating recess 311 at the front into which the rear portion 22 of the cylinder 2 is inserted. In this embodiment, the outer casing 3 is made up of the coupling 31 and the attachment 32.

[0017] The substantially cylindrical coupling 31 has a substantially bottomed cylindrical accommodating recess 311 formed at its front side into which the rear part 22 of the cylinder 2 is inserted. The accommodating recess 311 is formed with a smaller inner diameter at the portion deeper than the portion closer to the outlet, and the portion deeper than a step surface 312 is a small diameter portion 313. A pin hole 314 for inserting a fixing pin is formed in the small diameter portion 313 so as to penetrate the small diameter portion 313 in the diametrical direction. A female thread portion 315 is formed at the rear of the coupling 31.

[0018] The attachment 32 has a male threaded portion 322 formed on the front side of the base body 321, and a shank 323 formed on the rear side of the base body 321. The male threaded portion 322 is screwed into the male threaded portion 315 of the coupling 31, thereby screwing the attachment 32 to the coupling 31. The shank 323 is connected to a rotary drive machine such as a drill, and the rotational force of the rotary drive machine is transmitted to the exterior body 3, and the cylinder 2 and the extended diameter blade body 5 pinned thereto.

[0019] The compression spring 4 is provided at the rear portion 22 of the cylinder 2 so as to urge the cylinder 2 forward relative to the exterior body 3. In this embodiment, the compression spring 4, which is a coil spring, is fitted onto the outer periphery of the rear portion 22, and the rear end of the compression spring 4 abuts against the stepped surface 312 of the exterior body 3, and the front end of the compression spring abuts against the flange-shaped stopper 23, thereby urging the cylinder 2 forward relative to the exterior body 3.

[0020] The expanding blade body 5 has a thin plate-like or rod-like base body 51 extending in the axial direction of the cylinder 2, and an expanding blade 52 is formed at the front end portion located at the front side of the base body 51 so as to be inclined from the longitudinal direction of the base body 51. It is preferable that the expanding blade 52 portion or the entire expanding blade body 5 is made of a superhard material such as a superhard alloy. The expanding blade 52 has a long hole 53 formed extending in the inclined direction and separate from the long hole 221 of the cylinder 2, and in the illustrated example, the separate long hole 53 is formed at approximately the center of the expanding blade 52. In addition, a pin hole 54 for inserting a fixing pin is formed at the rear end portion of the expanding blade body 5.

[0021] The extended diameter blade body 5 extends in the axial direction of the cylinder 2 and is fitted inside the cylinder 2. The rear portion 22 of the cylinder 2 fitted with the extended diameter blade body 5 is inserted into the accommodation recess 311 of the exterior body 3, and the pin hole 54 of the extended diameter blade body 5, the long hole 221 of the cylinder 2 and the pin hole 314 of the exterior body 3 are aligned, and a removable fixing pin 6 is inserted into the pin hole 314, the long hole 221 and the pin hole 54 to be pinned. In other words, the exterior body 3 and the extended diameter blade body 5 are axially supported by the removable fixing pin 6 inserted into the long hole 221 of the cylinder 2.

[0022] In a state where it is pinned by this fixed pin 6, the expanding blade 52 of the expanding blade body 5 is disposed so as to face the vertical slit 212 of the cylinder 2, and is provided so as to be able to freely enter and exit the vertical slit 212. An eccentric pin 7 is detachably provided at the front end of the cylinder 2 by being inserted through a pin hole 211, and the eccentric pin 7 is inserted into another long hole 53 of the expanding blade 52. The other long hole 53 of the expanding blade 52 and the eccentric pin 7 fixed to the cylinder 2, in combination with the axial support by the fixed pin 6 of the expanding blade body 5 and the relative forward movement of the fixed pin 6 with respect to the long hole 221 of the cylinder 2, constitute a tilting mechanism of the expanding blade body 5.

[0023] When the exterior body 3 advances toward the flange-shaped stopper 23, this tilting mechanism moves the eccentric pin 7 relatively backward with respect to the inclined other oblong hole 53 in response to the relative forward movement of the fixed pin 6 with respect to the oblong hole 221, and tilts the expanding blade body 5 so that the expanding blade 52 protrudes outward from the vertical slit 212. Furthermore, when the external force that advances the exterior body 3 toward the flange-shaped stopper 23 is removed, the elastic restoration of the compression spring 4 causes the fixed pin 6 to move backward relative to the oblong hole 53 and the eccentric pin 7 to move forward relative to the other oblong hole 53, and the expanding blade 52 is accommodated inside the cylinder 2 from the vertical slit 212.

[0024] When forming an enlarged hole portion with the drilling and expanding tool 1, for example, a straight hole 101 is formed in concrete 100 with an existing drill tool, and then a front part 21 of the drilling and expanding tool 1 having a shape and size corresponding to the straight hole 101 is inserted into the straight hole 101, and the flange-shaped stopper 23 is brought into contact with the mouth of the straight hole 101 (see Figures 6(a) and (b)). Note that the rotary drive connected to the shank 323 is omitted in Figure 6.

[0025] Next, as shown in Fig. 6(c), the exterior body 3 is advanced against the elastic force of the compression spring 4 until it abuts against the flange-shaped stopper 23 of the cylinder 2. Fig. 5(a) shows the advanceable distance L of the exterior body 3. By this advancement, the fixed pin 6 moves from the rear end to the front end of the elongated hole 221, and the eccentric pin 7 moves from the front end to the rear end of another elongated hole 53, so that the enlarged diameter blade body 5 journaled by the fixed pin 6 tilts, and the enlarged diameter blade body 5 protrudes outside the vertical slit 212. By rotating the drilling and enlargement tool 1 in this state, an enlarged diameter drilling hole 102 with an enlarged diameter hole portion 103 is formed (see Figs. 6(c) and (d)).

[0026] In the formed enlarged diameter drilled hole 102, the mechanically fixed anchor 200 is fixed by expanding the expansion sleeve 201 in the enlarged diameter hole portion 103, or a hardened adhesive 302 is inserted together with a bolt 301 to fix the adhesive anchor 300, and the fixed mechanically fixed anchor 200 or adhesive anchor 300 is used to attach the required attachment.

[0027] According to the drilling and expanding tool 1 of this embodiment, the tool for forming the enlarged diameter hole portion 103 can be made to have a simple structure, and when the enlarged diameter blade 52 is damaged or deteriorated, the removable fixing pin 6 can be removed and disassembled on-site to easily replace the enlarged diameter blade body 5 for forming the enlarged diameter hole portion 103, thereby improving the efficiency of the drilling work and reducing the construction cost. In addition, due to the restoring force of the compression spring 4, the enlarged diameter blade 52 protruding outward from the vertical slit 212 can be smoothly restored to its original position after the work of forming the enlarged diameter hole portion 103.

[0028] Furthermore, by forming a vertical slit 212 extending in the axial direction in the front portion 21 having a shape and size corresponding to the straight hole 101, it is possible to prevent chips of concrete or the like from clogging between the enlarged diameter blade body 5 and the cylinder 2 when forming the enlarged diameter hole portion 103. Furthermore, the flange-shaped stopper 23 can prevent chips from entering the exterior body 3 when forming the enlarged diameter hole portion 103. Furthermore, by providing the flange-shaped stopper 23 and the vertical slit 212 on the front side of the flange-shaped stopper 23, it is possible to easily clean off chips adhering to the tool after the operation of forming the enlarged diameter hole portion 103.

[0029] Furthermore, by configuring the tilting mechanism with another long hole 53 of the expanding blade 52, the eccentric pin 7, and the pivot support by the fixed pin 6 of the expanding blade body 5, and a mechanism for moving the fixed pin 6 relative to the long hole 221 of the cylinder 2, when the expanding blade 52 is damaged or deteriorated, the removable fixed pin 6 and eccentric pin 7 can be pulled out and disassembled on-site, making it easier to replace the expanding blade body 5 that forms the expanded hole portion 103. Furthermore, the operation of inserting and removing the expanding blade 52 through the vertical slit 212 can be performed accurately and stably with a simpler structure.

[0030] In addition, by forming a vertical groove 213 extending in the axial direction on the outer peripheral surface of the front part 21 of the cylinder 2 at a circumferentially different position from the vertical slit 212, it becomes possible to introduce chips of concrete, etc. generated during the work of forming the enlarged diameter hole part 103 into the vertical groove 213, thereby more reliably preventing the chips from clogging the gap between the enlarged diameter blade body 5 and the cylinder 2.

[0031] [Scope of the invention disclosed herein] The invention disclosed in this specification includes, in addition to each invention, embodiment, and example listed as the invention, those specified by changing partial contents of these to other contents disclosed in this specification, those specified by adding other contents disclosed in this specification to these contents, or those specified by deleting partial contents of these to the extent that partial action and effect can be obtained, and specifying them as a higher conceptualization. The invention disclosed in this specification also includes the following contents and further modified examples described below.

[0032] For example, the tilting mechanism in the hole expanding tool of the present invention can be an appropriate tilting mechanism that tilts the expanding blade body so that the expanding blade protrudes outward from the vertical slit in response to the relative forward movement of the fixed pin with respect to the long hole. For example, instead of the configuration in which another long hole 53 is formed in the expanding blade 52 of the above embodiment, a tilting mechanism may be configured by forming another long hole in the base 51 of the expanding blade body 5 that is inclined in the same direction as the inclination of the expanding blade 52, and inserting an eccentric pin that is inserted into the pin hole in the front part 21 of the cylinder 2 into this other long hole.

[0033] Furthermore, the fixed pin 6 and the eccentric pin 7 are not limited to the shapes shown in the figures. In particular, since the fixed pin 6 is not provided at the location inserted into the straight 101 but is also a location where a large load is applied in order to support the extension blade body 5 at its base, it may be made into a bolt-like member protruding radially from the outer casing 3 to increase strength and ease of replacement.

[0034] In addition, the outer casing 3 in the above embodiment is configured by fastening the coupling 31 and the attachment 32 with a screw connection so that it can be replaced with an SDS-shaped or hexagonal shaft-shaped shank 323 depending on the chuck type of the rotary drive tool. However, the outer casing in the drilling and expanding tool of the present invention may be any appropriate one having a shank on the rear side and a roughly bottomed cylindrical accommodating recess on the front side into which the rear part of the cylinder is inserted. For example, the outer casing may be configured as an integrated member.

[0035] Furthermore, the shape of the internal space of the cylinder in the drilling and expanding tool of the present invention may be any appropriate shape as long as it allows the expansion blade body to be tilted. For example, if the entire expansion blade body has a roughly elongated plate-like shape, the internal space may be a groove-like shape whose width is slightly larger than the width of the expansion blade body. [Industrial Applicability]

[0036] The present invention can be used, for example, when drilling a hole in concrete with an enlarged diameter portion for attaching an anchor. [Explanation of symbols]

[0037] 1...Drilling and expanding tool 2...Cylinder 21...Front 211...Pin hole for inserting eccentric pin 212...Vertical slit 213...Vertical groove 22...Rear 221...Oval hole 23...Flange-shaped stopper 3...Exterior body 31...Coupling 311...Accommodating recess 312...Step surface 313...Small diameter portion 314...Pin hole for inserting fixed pin 315...Female thread portion 32...Attachment 321...Base body 322...Male thread portion 323...Shank 4...Compression spring 5...Expansion blade body 51...Base body 52...Expansion blade 53...Another oblong hole 54...Pin hole for inserting fixed pin 6...Fixed pin 7...Eccentric pin L...Advanceable distance of exterior body 100...Concrete 101...Straight hole 102...Expansion drilling 103...Expansion hole portion 200... Mechanical anchor type anchor 201... Expansion sleeve 300... Adhesive anchor 301... Bolt 302... Hardening adhesive

Claims

1. A drilling and expanding tool for forming an expanded hole portion in a straight hole already formed in a workpiece, comprising: a cylindrical front portion whose front end is closed and whose outer shape and size correspond to the straight hole to be drilled in the workpiece, a cylindrical rear portion having an elongated hole extending in the axial direction, and a circular flange-shaped stopper disposed between the front portion and the rear portion and having a larger diameter than both the front portion and the rear portion, and a substantially cylindrical cylinder having a vertical slit extending in the axial direction formed in the front portion; an exterior body having a shank provided on a rear side and a substantially bottomed cylindrical accommodation recess formed on a front side into which the rear part of the cylinder is inserted; a compression spring provided at a rear portion of the cylinder and biasing the cylinder forward relative to the exterior body; An enlarged diameter blade body that extends in the axial direction of the cylinder, is built into the cylinder, has an inclined enlarged diameter blade formed at a front end, and is provided so that the enlarged diameter blade can freely enter and exit the vertical slit; The exterior body and the expansion blade body are supported by a removable fixing pin that is inserted into the long hole of the cylinder, A drilling and expansion tool characterized in that a tilting mechanism is provided that tilts the expansion blade body so that the expansion blade protrudes outward from the vertical slit in response to the relative forward movement of the fixed pin with respect to the long hole.

2. The drilling and expanding tool according to claim 1, characterized in that the tilting mechanism is composed of another long hole formed in the expanding blade, extending in the direction in which the expanding blade is inclined, formed on the front side of the base of the expanding blade body extending in the axial direction of the cylinder so as to be inclined from the longitudinal direction of the base, and an eccentric pin that is detachably provided at the front end of the cylinder and inserted into the another long hole.

3. 3. The drilling and expanding tool according to claim 1, wherein a longitudinal groove extending in the axial direction is formed on the outer peripheral surface of the front part of the cylinder at a circumferential position different from that of the longitudinal slit.

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