Drill and drill device

Abstract

To provide a drill device and a drill capable of easily forming a hole widened part in a wooden member having a hole extending linearly.SOLUTION: A drill device forms a plurality of hole widened parts 22 in a wooden member 11 having a shaft core material insertion part 21 extending linearly at the same time. The drill device is provided with: a drill body; and a drill 65 attached in a rotary shaft part of the drill body and inserted into the shaft core material insertion part 21. The drill 65 comprises: an outer member 66 extending in an axial direction of the rotary shaft part; an inner member 75 extending in the axial direction and allowing an inner part of the outer member 66 to be slidable in the axial direction; and a cutting blade 76 rotatably attached on the inner member 75 and rotating in a projecting direction from an outer surface of the outer member 66 through sliding of the inner member 75 with respect to the outer member 66.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a drill and a drilling device for forming grooves on the side of a linearly extending hole formed in a piece of wood. [Background technology]

[0002] A known connection structure for connecting a wooden material to another component involves inserting a steel core material into a connection hole formed in the wooden material and then filling the gap between the wooden material and the core material with adhesive. Patent Document 1 also discloses such a connection structure, in which a connection hole is formed by a core material insertion section into which a core material (rod-shaped material) is inserted and hole widening sections (expanding filling grooves) provided in the core material insertion section. The hole widening sections are semicircular in a shaft cross section, which is a cross section along the axial direction of the core material, and are provided at predetermined intervals in the axial direction of the core material. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-123628 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when mortar or the like, which has higher heat resistance than adhesives, is used as a filler material, multiple hole widening sections are required to improve the adhesion between the filler material and the wood material. Therefore, there is a demand for a drill or drilling device that can easily form such hole widening sections. [Means for solving the problem]

[0005] A drilling device that solves the above problem simultaneously forms multiple hole enlargement portions in a piece of wood having a linearly extending hole. The drilling device includes a drill body and a drill attached to a rotary shaft of the drill body and inserted into the hole. The drill has an outer member extending in the axial direction of the rotary shaft, an inner member extending in the axial direction and slidable within the outer member, and a plurality of cutting blades rotatably attached to the inner member and rotating in a direction protruding from the outer surface of the outer member as the inner member slides relative to the outer member. [Effects of the Invention]

[0006] According to the present invention, the hole widening portion can be easily formed in the wood material. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view showing a schematic configuration of a state in which a connecting member is connected to a piece of wood in which a connecting hole has been formed using an embodiment of a drilling device and a drill, together with other members. [Figure 2] FIG. 2(a) is a view showing a state in which a shaft core member is inserted into a connection hole in a cross section along the axial direction, and FIG. 2(b) is an enlarged view of the part surrounded by line 2b. [Figure 3] FIG. 3(a) is a view showing a state in which the filler has been formed in an axial cross section along the axial direction, and FIG. 3(b) is an enlarged view of the part surrounded by line 3b. [Figure 4] FIG. 4 is a partial perspective view showing the connecting member. [Figure 5] FIG. 5 is a cross-sectional view showing a process of connecting a first wood piece and a second wood piece. [Figure 6] FIG. 6 is a diagram showing a schematic configuration of an embodiment of a drilling device. [Figure 7] FIG. 7 is a side view showing a schematic configuration of an embodiment of a drill. [Figure 8] FIG. 8 is a diagram showing the internal structure of the drill. [Figure 9]Figure 9(a) shows a drill in which the inner member is positioned at a first position, with the tip of the inner member abutting the innermost part of the core material insertion portion, Figure 9(b) shows an example of the inner member sliding from the first position to the second position, and Figure 9(c) shows the state in which a hole widening portion has been formed by the cutting blade. [Figure 10] Figure 10(a) shows a drill in which the inner member is positioned in the second position, with the tip of the inner member abutting the innermost part of the core material insertion section, Figure 10(b) shows the cutting blade rotating in the storage direction, Figure 10(c) shows the cutting blade stored in the storage section, and Figure 10(d) shows the drill being pulled out of the core material insertion section. [Figure 11] These are figures showing a modified example in which an outer member is attached to the rotating shaft portion of the drill body, where Figure 11(a) shows the tip of the outer member abutting the innermost portion of the core material insertion portion, and Figure 11(b) shows the state in which a hole widening portion is formed by the cutting blade. [Figure 12] FIG. 12 is a diagram showing the shape of a cutting guide portion in a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment of a drilling device and a drill will be described with reference to Figures 1 to 10. First, a connection structure using a connection hole having a hole widening portion formed by the drilling device and the drill will be described with reference to Figures 1 to 5.

[0009] As shown in Fig. 1, a connecting structure 10 axially connects a wooden member 11 and another member 12 with a connecting member 13. The wooden member 11 is a part of a member constituting a building, such as a pillar or a beam. The other member 12 is a part of a member constituting a building, such as a pillar, a beam, or a joint. The other member 12 may be a wooden member, or may be a precast material made of reinforced concrete, etc.

[0010] A connection hole 15 is formed in the wooden material 11. The connection hole 15 is a blind hole that extends in the axial direction and has an opening at a connection surface 11a, which is one end face in the axial direction. A core material 16 that constitutes the connection member 13 is inserted into the connection hole 15. In the connection structure 10, the axial direction is the direction in which the core material 16 extends. The core material 16 protrudes in the axial direction from the connection surface 11a. The wooden material 11 is connected to another member 12 by using the protruding portion of the core material 16. The core material 16 can be made of a material that is stronger than the wooden material 11, such as a deformed steel bar, a fully threaded bolt, or a glass fiber bar.

[0011] Filler 17 is formed in connecting hole 15 of wooden piece 11 to integrate wooden piece 11 and core material 16. Filler 17 is a hardened filler material with fluidity. The filler material is, for example, a cement-based material such as non-shrink mortar. Wooden piece 11 integrated with core material 16 by filler 17 is called wooden piece with connecting material 50.

[0012] It is preferable that a communication hole 18 communicating with the connection hole 15 is formed in the wooden material 11. The communication hole 18 has an opening in the side surface 11b of the wooden material 11. The communication hole 18 is formed so that the entire area of ​​the communication hole 18 overlaps with the connection hole 15 in a side view from the side surface 11b. The communication hole 18 communicates with the connection hole 15 at its innermost part. The communication hole 18 is a hole that is used when injecting a filler material that forms the filler 17 into the connection hole 15.

[0013] (Connection hole) 2(a), the connection hole 15 has a core material insertion portion 21 and a hole widening portion 22. The connection hole 15 is a hole whose outer shape in the width direction, which is a plane direction perpendicular to the axial direction, is circular.

[0014] The core insertion portion 21 is a portion that opens into the connection surface 11a and extends linearly from the connection surface 11a along the axial direction. The core insertion portion 21 is formed using a tool such as a drill. The innermost portion of the core insertion portion 21 is connected to the above-mentioned communication hole 18.

[0015] The hole widening portion 22 is a portion that is larger in the width direction than the core material insertion portion 21. The hole widening portion 22 is a groove formed on the side of the core material insertion portion 21. The hole widening portion 22 is provided at a predetermined interval in the axial direction. The hole widening portion 22 is formed using a special drill described below after the core material insertion portion 21 is formed. In Figure 2(a), the formation interval of the hole widening portion 22 is shown to be larger than the length of the hole widening portion 22 in the axial direction. With this configuration, the filler 17 can be formed with a small amount of filler material. On the other hand, the formation interval of the hole widening portion 22 may be smaller than the length of the hole widening portion 22 in the axial direction. With this configuration, more hole widening portions 22 can be formed.

[0016] Incidentally, when the core material 16 is a deformed rebar with a nominal diameter of 29, the diameter of the core material insertion portion 21 is about 45 mm, and the maximum diameter of the hole widening portion 22 is about 60 mm (diameter of the core material insertion portion 21 + 15 mm). In addition, the spacing between the hole widening portions 22 in the axial direction is preferably about 15 mm.

[0017] As shown in FIG. 2(b), the hole widening portion 22 has an inclined surface 25 and a withdrawal side end face 26. The inclined surface 25 is a surface that is farther away from the side surface of the core material insertion portion 21 as it approaches the connection surface 11a. The withdrawal side end face 26 is a surface that connects the end of the inclined surface 25 on the connection surface 11a side to the side surface of the core material insertion portion 21. In FIG. 2(b), the right direction in the figure is the back side direction of the core material insertion portion 21.

[0018] (Method of manufacturing wood materials with connecting material) An example of a method for manufacturing the connector-attached wood piece 50 will be described. First, the connecting hole 15 and the communication hole 18 are formed in the wood piece 11, and then the shaft core piece 16 is inserted into the connecting hole 15.

[0019] Thereafter, as shown in FIG. 3(a), the filler material is injected through the communication hole 18. The filler material is injected until the outflow of the filler material is confirmed from the opening of the connection hole 15 in the connection surface 11a. When the filler material hardens, a filler material 17 having an encapsulated portion 27 and an expanded portion 28 is formed in the connection hole 15. The encapsulated portion 27 is a portion formed in the core material insertion portion 21 that encapsulates the core material 16. The expanded portion 28 is a portion formed in the hole expanded portion 22 that has a larger diameter than the encapsulated portion 27. In the axial direction, the direction in which the core material 16 is pulled out of the connection hole 15 is called the pulling direction (upward in FIG. 3(a)), and the direction in which the core material 16 is pushed into the connection hole 15 is called the pushing direction (downward in FIG. 3(a)). In this way, the wood material 11 and the core material 16 are integrated by the filler material 17, thereby producing a wood material with a connector 50.

[0020] (widening section) As shown in FIG. 3(b), the widening portion 28 has a widening surface 34 and a reduced diameter surface 35. In FIG. 3(b), the right direction in the figure is the rear direction of the core material insertion portion 21. The widening surface 34 is a surface that adheres to the pull-out side end surface 26 of the hole widening portion 22. The widening portion 28 resists the pulling force that pulls the connecting material 13 out of the wood material 11 with the widening surface 34. The reduced diameter surface 35 is a surface that adheres to the inclined surface 25 of the hole widening portion 22. The reduced diameter surface 35 extends from the outer peripheral end of the widening surface 34 in the pushing direction and extends toward the inner portion 27 in the axial cross section. A partial perspective view of such a connecting material 13 is shown in FIG. 4.

[0021] (Method of connecting wooden pieces together) Referring to Fig. 5, an example of a connection method for connecting a first wooden piece, which is wooden piece 11, to a second wooden piece, which is another member 12, with a connecting member 13 will be described. The second wooden piece has the same configuration as the wooden piece 11 at the connection portion. Therefore, the same reference numerals as those used for the wooden piece 11 are used for the second wooden piece for the portions having the same configuration. In Fig. 5, the reference numerals on the right side relate to the first wooden piece, and the reference numerals on the left side relate to the second wooden piece.

[0022] First, the connecting member 13 is formed in the first wooden piece 11A, and the connecting hole 15 is formed in the second wooden piece 11B. The connecting hole 15 in the second wooden piece 11B has a communication hole 18 on the connecting surface 11a side and a communication hole 37 (see FIG. 5) that communicates with the innermost part of the core material insertion portion 21.

[0023] Next, as shown in Figure 5, the first wooden piece 11A and the second wooden piece 11B are aligned with the connecting surface 11a of the first wooden piece 11A facing the connecting surface 11a of the second wooden piece 11B, and the protruding portion of the core material 16 is inserted into the connecting hole 15 of the second wooden piece 11B.

[0024] Then, after the connecting surfaces 11a are brought into contact with each other, the filler material is filled through the communication holes 18 of the second wood piece 11B, as indicated by the dark dots. At this time, air inside the connection holes 15 of the second wood piece 11B is discharged through the communication holes 37. When the filler material hardens in the connection holes 15 of the second wood piece 11B, a filler material 17 is formed in the second wood piece 11B, and the first wood piece 11A and the second wood piece 11B are connected by the connection material 13.

[0025] (Method of forming connection holes) Next, a method for forming a connection hole in a wood material will be described. The method for forming a connection hole includes an insertion portion forming step in which a shaft core material insertion portion 21 is formed using a normal drill, and an enlarged portion forming step in which a hole enlarged portion 22 is formed using a drilling device described below.

[0026] As shown in FIG. 6 , the drilling device 55 includes a drill body 60 and a drill 65. The drill body 60 has a rotary shaft 62 that rotates around a central axis 61 when driven by a built-in drive source (not shown). The drill 65 is attached to the rotary shaft 62 so that its central axis coincides with the central axis 61. Preferably, the drill 65 is detachably attached to the rotary shaft 62 of the drilling device 55. Since the central axis 61 of the rotary shaft 62 coincides with the central axis of the drill 65, the central axis of the drill 65 will hereinafter also be referred to as the central axis 61. The direction in which the central axis 61 extends is the axial direction of the drilling device 55 and the drill 65. In the axial direction, the direction from the base end of the drill 65 to the tip end along the central axis 61 is the drill pushing direction. The direction from the tip end of the drill 65 to the base end along the central axis 61 is the drill pulling direction.

[0027] As shown in FIG. 7 , the drill 65 includes an outer member 66 and an inner member 75. The outer member 66 is attached to the rotary shaft portion 62 of the drill body 60. The outer member 66 is formed so as to be insertable into the shaft core insertion portion 21. The outer member 66 has a tubular shape extending along the central axis 61. The outer member 66 may be cylindrical or may have a polygonal tubular shape. The outer member 66 is composed of a first outer member 67 and a second outer member 68 extending along the central axis 61. The first outer member 67 and the second outer member 68 are joined together, for example, by screws (not shown).

[0028] As shown in Figure 8, the outer member 66 has a slide space 69 extending along the central axis 61. The slide space 69 has a polygonal cross-sectional shape. It is preferable that the slide space 69 has a rectangular cross-sectional shape. The slide space 69 communicates with the external space through the tip end surface of the outer member 66.

[0029] The inner member 75 extends through the slide space 69 along the central axis 61. The inner member 75 has a polygonal cross-sectional shape that fits into the slide space 69, which has a polygonal cross-sectional shape. For example, if the slide space 69 has a rectangular cross-sectional shape, the inner member 75 also has a rectangular cross-sectional shape. The inner member 75 is configured to be slidable (relatively movable) within the slide space 69 along the central axis 61. The inner member 75 is configured to be slidable between a first position where its tip protrudes a predetermined amount from the tip surface of the outer member 66 and a second position where it is accommodated in the slide space 69. The tip surface of the inner member 75 is preferably provided with a resistance suppression mechanism 75A, such as a rotating base, that suppresses penetration into the wood material 11 even when a pushing force is applied and suppresses rotational resistance of the drill 65. Note that FIGS. 7 and 8 illustrate the drill 65 with the inner member 75 in the first position.

[0030] A cutting blade 76 is attached to the inner member 75 at a position corresponding to the interval at which the hole widening portions 22 are formed. The base end of the cutting blade 76 is attached to the inner member 75 so as to be rotatable about a rotation axis 77 extending in a direction perpendicular to the plane of the drawing.

[0031] When the inner member 75 is in the first position, the cutting blades 76 are housed in housing portions 78 of the outer member 66 and extend outward in the drill withdrawal direction from the pivot shaft 77. More specifically, cutting blades 76 extending diagonally downward in FIG. 8 and cutting blades 76 extending diagonally upward in FIG. 8 are attached alternately from the tip side of the inner member 75.

[0032] The cutting blades 76 may be attached at intervals that are an integer multiple of the interval at which the hole widening portions 22 are formed. In this case, by attaching a spacing adjustment member to the tip of the drill 65, it is possible to form hole widening portions 22 at intermediate positions between the attachment intervals of the cutting blades 76. For example, if the attachment interval of the cutting blades 76 is 30 mm, by attaching a 15 mm spacing adjustment member, it is possible to form hole widening portions 22 with a pitch of 15 mm in the wood material 11. By configuring the spacing adjustment member to be detachable at the tip of the drill 65 in this way, it is possible to form hole widening portions 22 at intervals that are smaller than the attachment interval of the cutting blades 76.

[0033] The accommodation portion 78 extends outward in the drill withdrawal direction from the slide space 69. The accommodation portion 78 is formed to penetrate the peripheral wall of the outer member 66. The accommodation portion 78 also functions as a rotation passage when the cutting blade 76 rotates around the rotation shaft 77. The accommodation portion 78 is defined by a cutting guide portion 79 on the drill withdrawal direction side. The accommodation portion 78 is defined by a accommodation guide portion 80 on the drill pushing direction side.

[0034] An example of the step of forming the widened portion using the drilling device 55 will be described. 9(a), after attaching the drill 65 to the rotary shaft portion 62 of the drilling device 55, the drill 65, whose cutting blade 76 is housed in the housing portion 78, is inserted into the core material insertion portion 21. Then, the drill 65 is pushed in until the tip of the inner member 75 abuts against the innermost surface of the core material insertion portion 21.

[0035] Next, as shown in FIG. 9(b), the drill body 60 is driven to rotate the drill 65, and then the drill body 60 is operated to push the drill 65 in. This causes the outer member 66 to move relative to the inner member 75 in the drill pushing direction. As this relative movement occurs, the cutting blade 76 is guided by the cutting guide portion 79 in a direction (cutting direction) in which it protrudes from the outer member 66. In other words, the cutting guide portion 79 guides the cutting blade 76 in the cutting direction when the inner member 75 slides from the first position to the second position relative to the outer member 66. It is preferable that the multiple cutting blades 76 are configured to protrude on one side and the other side of the central axis 61 in the axial cross section of the drill 65. The portions of the cutting blades 76 that protrude from the outer surface of the outer member 66 cut the wood material 11.

[0036] 9(c), when the drill 65 is further pushed in, the inner member 75 is accommodated in the slide space 69 and reaches the second position. At this time, the cutting blade 76 is restricted from rotating in the cutting direction by the accommodation guide portion 80, and the amount of protrusion from the outer surface of the outer member 66 reaches its maximum. In this way, the hole widening portion 22 is formed in the wood material 11.

[0037] As shown in Figure 10(a), once the hole widening portion 22 is formed, the driving of the drill body 60 is stopped and then the drill 65 is pulled out from the core insertion portion 21. Here, in the drill device 55, an outer member 66 is attached to the rotation shaft portion 62 of the drill body 60. Also, in the drill 65, an inner member 75 is configured to be able to slide in a slide space 69. For these reasons, when the drill 65 is pulled out from the core insertion portion 21, the outer member 66 moves relative to the inner member 75 in the drill pulling direction.

[0038] 10(b), the cutting blade 76 is guided by the accommodation guide portion 80 to rotate in a direction (accommodating direction) in which the cutting blade 76 is accommodated in the accommodation portion 78. In other words, the accommodation guide portion 80 guides the rotation of the cutting blade 76 in the accommodation direction when the inner member 75 slides relative to the outer member 66 from the second position toward the first position.

[0039] 10(c), the outer member 66 is pulled out while the inner member 75 is pushed in. As a result, the inner member 75 is placed in the first position and the cutting blade 76 is housed in the housing 78. Thereafter, as shown in FIG. 10(d), the drill 65 is pulled out from the shaft core member insertion portion 21. As a result, the connecting hole 15 is formed in the wood material 11.

[0040] The operation and effects of this embodiment will be described. (1) The filler 17 has a plurality of widened portions 28 formed at intervals in the axial direction. This allows the wood material 11 to resist the pull-out force at a plurality of pull-out-side end faces 26. In other words, the wood material 11 can resist the pull-out force while effectively distributing the pull-out force across a plurality of pull-out-side end faces 26. As a result, splitting fracture caused by the pull-out force is less likely to occur in the wood material 11 than when there are fewer widened hole portions.

[0041] (2) By forming a plurality of widened portions 28, it is possible to reduce the diameter of the widened portions 28 while suppressing splitting fracture. As a result, for example, when a plurality of connecting members 13 are provided in the wood material 11, it is possible to reduce the edge distance dimension in the wood material 11.

[0042] (3) The drilling device 55 forms a hole widening portion 22 in a piece of wood 11 having a linearly extending shaft member insertion portion 21. The drilling device 55 includes a drill body 60 and a drill 65 that is attached to a rotary shaft portion 62 of the drill body 60 and inserted into the shaft member insertion portion 21. The drill 65 includes an outer member 66 that extends in the axial direction of the rotary shaft portion 62, an inner member 75 that extends in the axial direction and is slidable within the outer member 66, and a cutting blade 76 that is rotatably attached to the inner member 75 and rotates in a direction protruding from the outer surface of the outer member 66 as the inner member 75 slides.

[0043] As a result, by rotating the drill 65 inserted into the shaft core member insertion portion 21 and sliding the inner member 75 relative to the outer member 66, it is possible to simultaneously form multiple hole enlargement portions 22 in the wood material 11. As a result, it is possible to easily form the connecting hole 15 in the wood material 11, which is less susceptible to splitting fracture.

[0044] (4) The inner member 75 is configured to be slidable between a first position where the tip portion protrudes a predetermined amount from the tip surface of the outer member 66 and a second position where the tip portion is housed inside the outer member 66. In addition, the cutting blade 76 rotates in a direction protruding from the outer surface of the outer member 66 as the inner member 75 slides from the first position to the second position.

[0045] As a result, after inserting the drill 65 into the shaft core material insertion portion 21, multiple hole widening portions 22 can be formed simultaneously by simply pushing the drill 65 into the shaft core material insertion portion 21. In other words, since the hole widening portions 22 can be formed easily, the processing load involved in forming the hole widening portions 22 can be reduced.

[0046] (5) The outer member 66 has a sliding space 69 with a polygonal cross section, and the inner member 75 has a cross section that fits into the sliding space 69. This allows the rotational force of the rotating shaft portion 62 to be efficiently transmitted between the outer member 66 and the inner member 75.

[0047] (6) The multiple cutting blades 76 are attached to the inner member 75 so as to protrude on one side and the other side of the central axis 61 in the axial cross section of the drill 65. The multiple cutting blades 76 are configured to rotate simultaneously as the inner member 75 slides relative to the outer member 66. This makes it possible to suppress wobbling of the central axis 61 of the drill 65 during cutting. In other words, it is possible to suppress movement of the drill 65 during cutting.

[0048] (7) A resistance suppression mechanism 75A, such as a rotating base, is provided on the tip surface of the inner member 75 to suppress the inner member 75 from penetrating into the wood material 11 even when a pressing force is applied, and to suppress the rotational resistance of the drill 65. This suppresses the inner member 75 from penetrating into the wood material 11, and also suppresses the rotational resistance of the drill 65.

[0049] (8) A plurality of cutting blades 76 are attached to the inner member 75 at intervals to form the widened hole portions 22. This allows the widened hole portions 22 to be formed simultaneously, thereby shortening the processing time required to form the widened hole portions 22.

[0050] (9) The drill 65 may be configured such that a plurality of cutting blades 76 are attached to the inner member 75 at intervals that are an integral multiple of the interval at which the hole widening portions 22 are formed, and a spacing adjustment member is detachably attached to the tip of the inner member 75. This allows the hole widening portions 22 to be formed at intervals that are smaller than the interval at which the cutting blades 76 are attached.

[0051] (10) The outer member 66 has a housing portion 78 that houses the cutting blade 76. The housing portion 78 is defined by a cutting guide portion 79 on the drill-removal direction side. The housing portion 78 is defined by a housing guide portion 80 on the drill-pushing direction side. As a result, when the inner member 75 slides from the first position to the second position, the cutting guide portion 79 can guide the cutting blade 76 in the cutting direction. Furthermore, when the inner member 75 slides from the second position to the first position, the housing guide portion 80 can guide the cutting blade 76 in the housing direction.

[0052] This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility. The drill 65 may have a slide operating unit at its base end that slides the inner member 75 relative to the outer member 66 when the drill 65 is not rotating. The slide operating unit may be configured, for example, with an operating hole that extends in the axial direction and is formed in the peripheral wall of the outer member, and an operating handle that is joined to the inner member, passes through the operating hole, and is movable along the operating hole.

[0053] The cutting blade 76 may be attached to the inner member 75 in accordance with the hole widening portion 22 to be formed in the wood material 11. Therefore, the drilling device 55 and the drill 65 may each have a single cutting blade 76.

[0054] The drill 65 may have an inner member 75 attached to the rotation shaft portion 62 of the drill body 60, and the inner member 75 may slide in the slide space 69 as the outer member 66 moves relative to the inner member 75.

[0055] 11(a) and 11(b), in the above configuration, the cutting blade 76 and the housing portion 78 are configured to extend outward in the drill pushing direction. By pushing the inner member 75, the inner member 75 slides relative to the outer member 66, and the cutting blade 76 rotates in the cutting direction. Furthermore, since the drill 65 rotates with the tip surface of the outer member 66 abutting against the innermost surface of the shaft core insertion portion 21, it is preferable to provide a resistance suppression mechanism on the tip surface of the outer member 66.

[0056] In the cutting guide portion 79 of the drill 65 in the above embodiment, the portion that comes into contact with the cutting blade 76 in the axial cross section of the drill 65 is formed at an acute angle. 12, the cutting guide portion 79 preferably has a curved portion 79A that curves toward the central axis 61 in the axial cross section of the drill 65 as the portion that comes into contact with the cutting blade 76. With this configuration, the load on the cutting blade 76 when it comes into contact with the cutting guide portion 79 is reduced, and the cutting blade 76 can be smoothly guided in the cutting direction.

[0057] The technical ideas that can be understood from the above-described embodiment and modified examples will be described. (Appendix 1) The plurality of cutting blades are attached to the inner member at intervals that define the widened hole portions.

[0058] (Appendix 2) The outer member has a storage section that stores the cutting blades, a cutting guide section that defines the storage section and guides the cutting blades when the inner member slides from the first position to the second position, and a storage guide section that defines the storage section and guides the multiple cutting blades so that they rotate in a direction to be stored in the storage section when the inner member slides from the second position to the first position. [Explanation of symbols]

[0059] 10...connection structure, 11...wooden material, 11a...connection surface, 11A...first wooden material, 11B...second wooden material, 11b...side surface, 12...other member, 13...connection material, 15...connection hole, 16...core material, 17...filler material, 18...communicating hole, 21...core material insertion portion, 22...hole widening portion, 25...inclined surface, 26...pulling-out side end surface, 27...container portion, 28...widening portion, 34...widening surface, 35...diameter reduction surface, 37...connection Through hole, 50...wood material with connecting material, 55...drilling device, 60...drill body, 61...center axis, 62...rotating shaft portion, 65...drill, 66...outer member, 67...first outer member, 68...second outer member, 69...slide space, 75...inner member, 75A...resistance suppression mechanism, 76...cutting blade, 77...rotating shaft, 78...accommodation portion, 79...cutting guide portion, 79A...curved portion, 80...accommodation guide portion.

Claims

1. A drilling device for simultaneously forming a plurality of hole widening portions in a wooden material having a linearly extending hole, a drill body; and a drill attached to a rotation shaft portion of the drill body and inserted into the hole, The drill an outer member extending in the axial direction of the rotary shaft; an inner member extending in the axial direction and slidable in the outer member in the axial direction; a plurality of cutting blades rotatably attached to the inner member and rotatably moving in a direction protruding from the outer surface of the outer member as the inner member slides relative to the outer member; Drilling equipment.

2. The outer member is attached to the rotating shaft portion, the inner member is configured to be slidable between a first position where a tip portion thereof projects by a predetermined amount from a tip surface of the outer member and a second position where the tip portion thereof is accommodated inside the outer member, The plurality of cutting blades rotate in a direction protruding from the outer surface of the outer member as the inner member slides from the first position to the second position.

2. The drilling device of claim 1.

3. A drill that is inserted into a linearly extending hole and simultaneously forms a plurality of hole widening portions in a wood material having the hole, an outer member extending in the axial direction of the drill; an inner member extending in the axial direction and slidable in the outer member in the axial direction; a plurality of cutting blades that are rotatably attached to the inner member and that rotate in a direction protruding from the outer surface of the outer member as the inner member slides; drill.

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