Piercing tool

Abstract

To prevent the peripheral edge part of a bored circular through-hole from being damaged by a boring depth regulating member for regulating the boring depth of a boring blade body to a body to be bored.SOLUTION: A drilling tool H that is attached to a rotary tool D and drills a circular through-hole K in a wall body W includes a cover body C that is attached integrally to a first rotary force transmission member T1 and is disposed on the outer side of the entire drilling blade body N, and an end portion of the drilling blade body N on the drilling blade side in the cover body C that is supported by the cover body C so as to be rotatable idle with respect to the cover body C in a state of protruding from the end portion. And an idling body F for determining the drilling depth by abutting on the peripheral edge part of the circular through-hole K of the wall body W without rotating immediately before finishing the drilling.SELECTED DRAWING: Figure 20

Description

[Technical Field]

[0001] The present invention relates to a drilling tool that is attached to a rotary tool and is used to drill a through hole in a body to be drilled, such as a wall body. [Background technology]

[0002] The above-described drilling tool is attached to a rotary tool and forms a through hole by pressing a drilling blade, which is rotated by the power of the rotary tool, against a workpiece. It is also called a "hole saw." While many drilling tools are designed to drill circular through holes, the drilling tool disclosed in Patent Document 1 forms an oval-shaped through hole. The cover body 2 covering the outside of the blade body 15 defines the overall shape of the blade body 15, and the blade body 15 rotates in an oval-shaped path while constantly sliding against the inner peripheral surface of the cover body 2. This results in a large sliding load acting on the blade body 15, making it susceptible to damage and requiring a large amount of power to drive and rotate the blade body 15.

[0003] The drilling tool disclosed in Patent Document 2 drills a circular through-hole, and uses holes 2 formed in a cylindrical hole saw body 1 along the drilling direction to adjust the position of a ring 5 fitted around the hole saw body 1 for adjusting the drilling depth. Because the ring 5 rotates integrally with the hole saw body 1, there is a problem in that just before drilling is completed, the ring 5 slides against the periphery of the circular through-hole, damaging it and spoiling the aesthetic appearance of the drilled hole 2. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-269399 [Patent Document 2] Japanese Utility Model Application Publication No. 62-46516 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to prevent the peripheral edge of a drilled circular through hole from being damaged by a drilling depth regulating member that determines the drilling depth of the drilling blade in the object to be drilled. [Means for solving the problem]

[0006] The invention of claim 1 to solve the above problem is as follows: a center shaft portion having a center drill for drilling the center of the circular through hole before drilling the circular through hole; a perforating blade body that is disposed outside the center shaft portion and is driven to rotate by a rotational force of the center shaft portion transmitted thereto via a rotational force transmission member, A drilling tool attached to a rotary tool for drilling a circular through hole in a workpiece, a cover body that is attached integrally to the rotational force transmission member or the perforation blade body so as to rotate together with the rotational force transmission member or the perforation blade body and is disposed on the entire outer side of the perforation blade body; an idler body that is supported on the cover body at an end of the cover body on the side of the perforation blade of the perforation blade body in a state of protruding from the end and that can idle relative to the cover body, and that abuts non-rotatably on the peripheral portion of the circular through-hole of the object to be perforated; It is characterized by having the following.

[0007] According to the invention of claim 1, in a drilling tool in which the rotational force of the center shaft is transmitted to the drilling blade body via a rotational force transmission member, driving the drilling blade body to rotate and drilling a circular through hole in a body to be drilled, a cover body arranged on the outside of the drilling blade body is integrally attached to the rotational force transmission member or the drilling blade body so as to rotate together, and an idler is supported on the end of the cover body facing the drilling blade, protruding from said end, so that the idler abuts non-rotatingly on the peripheral edge of the drilled circular through hole, causing the drilling blade body to drill the body to a maximum depth determined by the position of the idler relative to the drilling blade body in the drilling direction, and the work is completed. As a result, the peripheral edge of the drilled circular through hole is not damaged in any way, preventing the peripheral edge of the circular through hole from collapsing and impairing its appearance.

[0008] The invention of claim 2 is characterized in that in the invention of claim 1, the idler body is annular and has an inner diameter larger than the inner diameter of the cover body.

[0009] According to the invention of claim 2, the idler body is annular and has an inner diameter larger than the inner diameter of the cover body arranged outside the perforation blade body, so that the perforation blade of the perforation blade body is not damaged by the idler body.

[0010] The invention of claim 3 is characterized in that in the invention of claim 2, the idler body is fitted onto the end of the cover body on the side of the perforation blade of the perforation blade body.

[0011] According to the invention of claim 3, the idler, which determines the drilling depth of the drilling blade body in the object to be drilled, is fitted onto the end of the cover body on the drilling blade side of the drilling blade body, and the abutment part at the tip of the idler is arranged to protrude in the drilling direction from the tip face of the cover body, so that the abutment part provided at the tip of the idler that abuts against the object to be drilled can be arranged as close to the drilling blade body as possible while avoiding contact with the drilling blade body. As a result, just before the drilling blade body finishes drilling the object to be drilled, the abutment part can be arranged close to the periphery of the drilled through hole, enabling stable drilling work.

[0012] The invention of claim 4 is the invention of any one of claims 1 to 3, wherein the center shank portion is assembled to the drive square tube shaft so that a center drill can move in and out, and the rotational force of the center shank portion is transmitted to the drill blade body via the rotational force transmission member that is fitted non-rotatably on the drive square tube shaft, The cover body is characterized in that it is assembled integrally with the rotational force transmission member so that its position along the drilling direction can be adjusted relative to the rotational force transmission member.

[0013] According to the invention of claim 4, the cover body is integrally assembled with the rotational force transmission member so that its position along the drilling direction can be adjusted, and therefore the protruding length of the drilling blade body relative to the cover body can be changed, thereby adjusting the drilling depth of the circular through hole created by the drilling blade body. [Effects of the Invention]

[0014] According to the present invention, a cover body arranged on the outside of the drilling blade body is attached integrally to a rotational force transmission member for transmitting the rotational force of the center shaft to the drilling blade body or to the drilling blade body so as to rotate together, an idler body is supported on the end of the cover body on the drilling blade side of the drilling blade body in a state where it protrudes from the end, and the idler body abuts without rotating on the peripheral edge of the drilled circular through hole, so that the drilling blade body drills the object to a maximum depth determined by the position of the idler body in the drilling direction, and the work is completed. As a result, the peripheral edge of the drilled circular through hole is not damaged in any way, and it is possible to prevent the peripheral edge of the circular through hole from collapsing and deteriorating its appearance. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a perspective view of a punching tool H of the present invention attached to a rotary tool D in a punching state. [Figure 2] FIG. 2 is a perspective view of the punching tool H in a non-punching state. [Figure 3] 1 is a front view showing the punch body B and the cover body C separated from each other. FIG. [Figure 4] FIG. 2 is a longitudinal cross-sectional view of the punching tool H during punching. [Figure 5] (a-1), (b), and (c) are cross-sectional views taken along lines X1-X1, X2-X2, and X3-X3 in FIG. 4, respectively, and (a-2) is a cross-sectional view taken along line X4-X4 in (a-1). [Figure 6] FIG. 2 is a perspective view of the punching tool body B when not punching. [Figure 7] FIG. 2 is an exploded perspective view of the punch body B. [Figure 8]1(a) is a perspective view of a state in which a punch blade body N is integrally attached to a first torque transmission member T1, and FIG. 1(b) is a cross-sectional view taken along line YY in FIG. [Figure 9] 10 is a partially cutaway perspective view showing a state in which a pair of locking portions 17 of a first torque transmission member T1 are engaged with a pair of locking holes 5 at the base end of a perforation blade body N. FIG. [Figure 10] 10(a) and 10(b) are perspective views of the first rotational force transmission member T1 as viewed from different directions, and 10(c) to 10(e) are a plan view, a front view, and a bottom view of the rotational force transmission body T, respectively. [Figure 11] 10(a) to 10(d) are cross-sectional views taken along the lines Z1-Z1, Z2-Z2, Z3-Z3 and Z4-Z4 in FIG. 10(c), respectively. [Figure 12] (a) is an exploded oblique view of a fixing device G for fixing the cover body C to a predetermined position along the drilling direction relative to the rotational force transmission body T that constitutes the drilling tool main body B, and (b) and (c) are oblique views of the assembled state as seen from different directions. [Figure 13] 10(a) and 10(b) are perspective views of a cover body C, with an idling body F fitted onto the tip end along the drilling direction so as to be idling, as viewed from different directions. [Figure 14] FIG. [Figure 15] FIG. [Figure 16] 1(a) to 1(c) are a front view, a plan view, and a bottom view of the cover body C, respectively, and 1(d) and 1(e) are vertical cross-sectional views of different parts of the cover body C. FIG. [Figure 17] 1(a) to 1(d) are a plan view, a front view, a bottom view and a cross-sectional view of the idler F, respectively. [Figure 18] 10(a) and 10(b) are a front view and a front cross-sectional view of the punching tool H in a non-punching state in which the punching blade body N is fully retracted relative to the cover body C. FIG. [Figure 19] 10(a) and 10(b) are a front view and a front cross-sectional view of the punching tool H in a punching state in which the punching blade body N is protruded to the maximum relative to the cover body C. FIG. [Figure 20]1(a) to 1(c) are cross-sectional views showing the order in which a circular through-hole K is drilled in a wall W by a drilling tool H. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention will be described in more detail below with reference to examples. As shown in Figures 1 to 4, a drilling tool H according to the present invention is attached to a rotary tool D and used to drill a circular through hole K (see Figure 20 for all) in a wall W, which is an object to be drilled, and comprises a center shaft portion S of a double shaft structure in which a center drill 2 is inserted into a driving square tube shaft 1 while being biased in a protruding direction by the biasing force of a compression spring 3, a first rotational force transmission member T1 fitted externally to the driving square tube shaft 1 so as to be integrally rotatable and transmitting the rotational force of the driving square tube shaft 1 to a drilling blade N, the drilling blade N attached integrally to the first rotational force transmission member T1, and a second rotational force transmission member T2. The drilling tool H includes a second torque transmission member T2 that transmits the torque transmitted to the reach member T1 to the center drill 2 to drive and rotate the center drill 2, a cover body C that is disposed outside the drilling blade body N and rotates integrally with the first torque transmission member T1, and an idler body F that is fitted onto the tip of the cover body C in the drilling direction so as to be idling relative to the cover body C and that is pressed non-rotatingly against the periphery of a circular through hole K drilled in the wall body W just before the drilling of the wall body W is completed by the drilling blade body N, thereby determining the drilling depth of the drilling blade body N in the wall body W. As shown in Figures 3 and 4, the portion of the drilling tool H from which the cover body C and the idler body F have been removed constitutes a drilling tool main body B. The driving square tube shaft 1, center drill 2, compression spring 3 and drilling blade body N that constitute the center shaft portion S are made of metal, while the first and second rotational force transmission members T1, T2, cover body C and idling body F are made of resin.

[0017] The center shank S has a double shaft structure in which a center drill 2 is inserted into a central hole 1a with a circular cross section of a square cylindrical drive shaft 1 having an outer shape with a regular hexagonal cross section, while being biased in the protruding direction by the biasing force of a compression spring 3, and the square cylindrical drive shaft 1 is inserted into a square hole 13 of a cylindrical portion 11 of a first rotational force transmission member T1 so as not to be removed, and is integrated with the first rotational force transmission member T1. The first rotational force transmission member T1 is an entire, single member that transmits the driving torque of the square cylindrical drive shaft 1 of the center shank S to the drill bit N and drives and rotates the drill bit N assembled integrally with it, and as shown in Figures 10 and 11, a circular cup portion 12 is integrally formed at one axial end of the cylindrical portion 11, and an engaging portion 13a with a circular inner circumferential surface is formed inwardly at the axial center of the square hole 13 of the cylindrical portion 11, thereby firmly attaching the square cylindrical drive shaft 1 of the center shank S to the cylindrical portion 11. When the square tubular drive shaft 1 is pressed in with force, the difference in hardness between the materials of the square tubular drive shaft 1 and the first torque transmission member T1 causes the tip of the square tubular drive shaft 1 to break part of the engagement portion 13a, and a circular cross-sectional engagement recess 1b located near the tip of the square tubular drive shaft 1 engages with the engagement portion 13a of the square hole 13 in the cylindrical portion 11, forming a "fixed engagement structure" that prevents the square tubular drive shaft 1 from rotating circumferentially relative to the first torque transmission member T1 and moving axially. The square tubular drive shaft 1, which constitutes the center shaft S, is integrally provided with a shank 8, which is inserted into the drive shaft 71 of the rotary tool D to transmit torque. A pair of elongated chip discharge through-holes 9 are formed in the square tubular drive shaft 1 adjacent to the shank 8, facing each other along the axial direction. Therefore, chips that get in between the center drill 2 of the dual-shaft structure and the drive shaft 1 during drilling reach the internal space of the drive shaft 1 as the center drill 2 moves in and out of the drive shaft 1 multiple times, and are then discharged to the outside through the pair of chip discharge through-holes 9. This prevents chips from reaching the drive shaft 71 of the rotary tool D, enabling smooth transmission of rotational force over a long period of time.

[0018] The circular cup portion 12 of the first torque transmission member T1 is open at one axial end when integrated with the cylindrical portion 11, and a pair of rod insertion holes 15 are provided in a top wall portion 14 of the circular cup portion 12 so that a pair of rod bodies 31 constituting the second torque transmission member T2 are inserted from the cylindrical portion 11 side to assemble it to the first torque transmission member T1. As shown in Figures 6 and 7, the perforating blade body N is formed by bending a flat blade plate into an incomplete cylindrical shape with no blade body in part of the circumferential direction, and in the bent state, a pair of locking holes 5 are provided facing each other at one axial end, and a plurality of perforating blades 6 are formed at the other axial end. The locking hole 5 is formed in the axial direction and consists of a first locking hole 5a that is open at one end in the axial direction, and a second locking hole 5b that is formed in the circumferential direction and connected to the rear part of the first locking hole 5a, and as a whole has the shape of an "L" turned sideways by 90 degrees.

[0019] A predetermined length portion of the base end of the incomplete cylindrical perforation blade body N is inserted into the inside of the circular cup portion 12 of the first rotational force transmission member T1, and this predetermined length portion is positioned in close contact with the inner surface of the peripheral wall portion 16 of the circular cup portion 12 due to the restoring force tending to expand its diameter.The pair of engagement holes 5 are engaged with a pair of engagement portions 17 (see Figures 9, 10 and 11(b)) protruding oppositely from the peripheral wall portion 16, so that the incomplete cylindrical perforation blade body N is assembled integrally with the axial direction of the circular cup portion 12 of the first rotational force transmission member T1. 9 and 11(b), the pair of locking portions 17 are formed by forming locking space-forming holes 18 in the form of blind holes in portions of the top wall portion 14 of the circular cup portion 12 that are circumferentially out of phase with the pair of rod body insertion holes 15 by 90°, and are formed so that the pair of locking portions 17 protrude inward from the inner peripheral surface of the peripheral wall portion 16, with the bottom surface of the locking space-forming holes 18 serving as the upper surface. Due to the presence of the locking space-forming holes 18, the insertion protrusions 7 directly above the second locking holes 5b of the pair of locking holes 5 formed in the perforating blade body N can be inserted into the locking space-forming holes 18, thereby enabling the pair of locking holes 5 of the perforating blade body N to be locked with the pair of locking portions 17 formed in the circular cup portion 12 of the first rotational force transmission member T1.

[0020] To integrally assemble the base end of the perforating blade body N to the circular cup portion 12, as shown in Figure 9, from the opening side of the circular cup portion 12, the base end of the perforating blade body N is partially inserted into the interior of the circular cup portion 12 while aligning each of the first locking holes 5a of the pair of locking holes 5 at the base end of the perforating blade body N with each of the locking portions 17 of the circular cup portion 12, and then the perforating blade body N is rotated in a predetermined direction to insert each of the locking portions 17 of the circular cup portion 12 into each of the second locking holes 5b of the perforating blade body N, thereby engaging each of the locking portions 17 with each of the second locking holes 5b, and the perforating blade body N is assembled to the circular cup portion 12 so that it cannot be removed. A screw pilot hole 19 is formed near one of the locking space forming holes 18 in the top wall portion 14 of the circular cup portion 12, and when a locking screw 21 is screwed into the screw pilot hole 19, as shown in Figure 9, the locking screw 21 abuts against the end face away from the second locking hole 5b in the first locking hole 5a of one of the locking holes 5 of the perforation blade body N, thereby restricting the rotation of the perforation blade body N in the direction of releasing the lock between each second locking hole 5b of the perforation blade body N and each locking portion 17 of the circular cup portion 12.This, combined with the restriction of movement of the perforation blade body N in the removal direction due to the engagement between the locking portion 17 of the first rotational force transmission member T1 and the second locking hole 5b of the perforation blade body N, maintains the perforation blade body N assembled integrally with the circular cup portion 12.

[0021] An assembly protrusion 22 protrudes in the axial direction of the first rotational force transmission member T1 and is integrally provided near the other locking space-forming hole 18 on the peripheral edge of the top wall 14 of the circular cup portion 12. The assembly protrusion 22 is used to assemble the cover body C to the first rotational force transmission member T1 in an adjustable assembly position along the axial direction of the first rotational force transmission member T1. A bolt insertion hole 23 is formed in the assembly protrusion 22 along the radial direction perpendicular to the axial direction of the first rotational force transmission member T1, and a nut body 24 is embedded in the middle of the bolt insertion hole 23.

[0022] An inner peripheral wall portion 25 is integrally provided inside the peripheral wall portion 16 of the top wall portion 14 of the circular cup portion 12, with a predetermined diameter gap between it and the peripheral wall portion 16 and extending into the interior through the opening of the circular cup portion 12. A pair of axial openings 26 are provided in the inner peripheral wall portion 25 at portions corresponding to the pair of rod body insertion holes 15, into which reinforcing ribs 31a1 of a pair of rod body main bodies 31a described below can be inserted, and these openings are connected to the pair of rod body insertion holes 15.

[0023] The rotational drive force of the drive square tube shaft 1 of the center shank S is transmitted to a first rotational force transmission member T1, which is integrally assembled with the drive square tube shaft 1. A pair of rod bodies 31 constituting a second rotational force transmission member T2, which transmits rotational force to a center drill 2 constituting the center shank S, is assembled to the first rotational force transmission member T1. The second rotational force transmission member T2 is a member integrally assembled with the center drill 2 and constituted by assembling a plurality of component elements for transmitting the rotational force of the first rotational force transmission member T1 to the center drill 2. As shown in Figures 6 and 7, the second rotational force transmission member T2 comprises a pair of rod bodies 31 inserted into a pair of rod body insertion holes 15 formed in the circular cup portion 12 of the first rotational force transmission member T1 from the top wall portion 14 side of the circular cup portion 12, and a pair of clamping block bodies 32 assembled to the tip ends of the pair of rod bodies 31 and clamping and holding the tip end of the center drill 2 together.

[0024] The pair of rod bodies 31 are members for transmitting the rotational force (power) of the first rotational force transmission member T1 to the center drill 2, and are configured such that a hook flange portion 31b, which abuts against the outer surface of the top wall portion 14 of the first rotational force transmission member T1 in an assembled state, is integrally formed at one longitudinal end of the rod body main body 31a, perpendicular to the longitudinal direction of the rod body main body 31a, and an assembly pin 31c is provided at the other end protruding on the side where the hook flange portion 31b is provided. The pair of clamping block bodies 32 are assembled together via their flat contact surfaces and are located within the internal space of the incompletely cylindrical drill blade body N assembled integrally to the first torque transmission member T1. Each rod 31 is inserted through a pair of rod insertion holes 15 in the top wall 14 of the circular cup portion 12 of the first torque transmission member T1. Half of the width of the tip of the rod 31 is engaged with the corresponding clamping block body 32 via an assembly pin 31c, and the tip of the center drill 2 is clamped together via a light metal crimped pipe 33. The pair of clamping block bodies 32 are joined together via a pair of clamping bolts 34 and a pair of clamping nuts 35, with a compression spring 3 disposed outside the center drill 2. A reinforcing rib 31a1 is provided along the longitudinal direction on the outer side of the rod body main body 31a of each rod 31 when assembled.

[0025] Therefore, as shown in Figures 4 and 5(c), the crimping pipe body 33 fitted onto the tip of the center drill 2 is crimped by clamping it between a pair of clamping block bodies 32, so that the pair of clamping block bodies 32 and the center drill 2 are integrated and can rotate together, and a compression spring 3 is arranged between the inner end surface of the cylindrical portion 11 of the first rotational force transmission member T1 and the inner end surfaces of the pair of clamping block bodies 32 assembled together to form the second rotational force transmission member T2.As a result, the center drill 2 is always biased in the protruding direction by the biasing force of the compression spring 3, with the maximum protruding length relative to the driving square tube shaft 1 being restricted by each of the hook flange portions 31b of the pair of rod bodies 31.

[0026] A cover body C is attached integrally to the first torque transmission member T1 on the outside of the perforation blade body N of the perforation tool main body B so that its position along the axial direction of the perforation blade body N can be changed. As shown in Figures 13 to 17, the cover body C is a cylindrical member that is arranged with a predetermined gap on the outside of the perforation blade body N assembled to the first torque transmission member T1, and the end of the cover body main body 41 on the perforation blade 6 side of the perforation blade body N is provided with an idling body loose fitting portion 42 that is formed with a smaller diameter than other portions, and an engaged portion 43 that also serves as a stopper flange is formed on the end of the idling body loose fitting portion 42. To make it possible to change the mounting position of the cover body C relative to the first torque transmission member T1 along the axial direction of the drilling blade body N and to adjust the drilling depth of the drilling blade body N, the cover body main body 41 is formed with an elongated fixing bolt insertion hole 44 along its axial direction, and on both circumferential sides of the fixing bolt insertion hole 44, cover body side teeth 45 that mesh with seat plate side teeth 65 formed on the inner surface of a seat plate 61 that has an arc-shaped vertical cross section, described below, are formed continuously along the fixing bolt insertion hole 44, and a drilling depth scale 46 that indicates the drilling depth of the drilling blade body N is formed on the cover body main body 41 along the cover body side teeth 45 formed on one side of the fixing bolt insertion hole 44. A linear indicator mark 67 that indicates the drilling depth scale 46 formed along the axial direction on the outer peripheral surface of the cover body main body 41 is formed on the surface of the seat plate 61 along the curvature of the seat plate 61. When not drilling, the cover body C functions as a protective cover to cover the entire drilling blade body N, and when the entire drilling blade body N is covered by the cover body C, as shown in Figure 2, the fixing bolt 63 inserted into the fixing bolt insertion hole 44 is positioned in a portion of the cover body main body 41 near the end opposite the idler loose fitting portion 42, securing the corresponding end forming portion of the fixing bolt insertion hole 44, and the portion of the cover body main body 41 corresponding to the end forming portion is provided with a bulge portion 47 (see Figures 3 and 14) that bulges in the axial direction.

[0027] The idler F is an annular member that is loosely fitted onto the idler loose fitting portion 42 of the cover body main body 41 in an external state that allows it to idle (rotate freely), and a plurality of (four in this embodiment) engaging portions 51 are formed at regular intervals along the circumferential direction on the inner peripheral surface of one axial end portion, and a ring-shaped abutment portion 52 is formed at the other axial end portion that abuts against the periphery of the circular through hole K drilled in the wall body W just before the drilling of the wall body W by the drilling tool H is completed. The ring-shaped abutment portion 52 has a plurality of arc-shaped holes 52a formed in it to prevent sink marks, underfill, etc. during injection molding with resin and to ensure the flatness of the abutment surface of the abutment portion 52.

[0028] When the engaged portion 43 of the cover body main body 41, which also serves as a retaining flange, and the engaging portion 51 of the idling body F are opposed to each other and the idling body F is pressed against the cover body main body 41 with a strong force, the engaging portion 51 is elastically deformed and then restored to its original shape, and the idling body F is loosely fitted into the idling body loose fitting portion 42 of the cover body main body 41 in a retained state so as to be able to idly rotate, as shown in Figure 4.

[0029] To assemble the cover body C to the assembly protrusion 22 of the first rotational force transmission member T1 in a manner that allows the positioning position of the cover body C along the axial direction to be changed, as shown in Figure 12, a fixing device G is used that consists of a seat plate 61 having an arc-shaped vertical cross section that corresponds to the outer peripheral surface of the cover body C, a fixing bolt 63 that is inserted into both a fixing bolt insertion hole 62 formed in the center of the seat plate 61 in both the vertical and horizontal directions and the fixing bolt insertion hole 44 of the cover body C and is screwed into a nut body 24 embedded in the assembly protrusion 22, and a compression spring 64 that is elastically mounted between the seat plate 61 and the outer peripheral surface of the cover body C. On both sides of the back surface of the seat plate 61 along the longitudinal direction (curvature direction) of the fixing bolt insertion hole 62, seat plate side tooth portions 65 are formed which engage with the cover body side tooth portions 45 formed on the cover body C, and on both sides of the back surface of the seat plate 61 along the width direction of the fixing bolt insertion hole 62, anti-slip protrusions 66 are protruded to prevent lateral slippage of the compression spring 64.

[0030] To assemble the cover body C integrally with the first torque transmission member T1 so that its axial position is adjustable, the cover body C is placed outside the drilling blade body N with its position relative to the axial direction of the drilling blade body N determined, as shown in Figures 1, 3, 5(a-1), 5(a-2), and 12. In this state, a compression spring 64 is placed on the rear surface of the seat plate 61, and the seat plate side teeth 65 on the rear surface of the seat plate 61 are engaged with the cover body side teeth 45 of the cover body C. Then, a fixing bolt 63 inserted through the fixing bolt insertion holes 44, 62 of the seat plate 61 and the cover body C is screwed into a nut body 24 embedded in the assembly protrusion 22 of the first torque transmission member T1. As a result, the cover body side teeth 45 provided on both sides of the elongated fixing bolt insertion hole 44 of the cover body main body 41 and along the fixing bolt insertion hole 44 engage with the seat plate side teeth 65 formed on the back surface of the seat plate 61, and the cover body C is assembled integrally with the first rotational force transmission member T1 in a state in which the seat plate 61 cannot slide in the direction of the fixing bolt insertion hole 44 relative to the cover body main body 41.

[0031] When the punching tool H is not in use, the punching blade body N is entirely housed in the cover body C, as shown in Figure 18, and the punching blade body N is protected by the cover body C. When the punching tool H is in use, as shown in Figures 1 and 19, the cover body C is attached to the first torque transmission member T1 of the punching tool main body B using the fixing device G, with the punching blade body N projecting a predetermined length from the cover body C, or more precisely, from the idler body F loosely fitted at the tip of the cover body C, corresponding to the punching depth. When the punching blade body N is entirely housed in the cover body C, the indicator mark 67 displayed on the seat plate 61 points to "0" on the drilling depth scale 46 displayed on the cover body C, and when the punching blade body N projects a predetermined length from the cover body C, the indicator mark 67 on the seat plate 61 points to the number on the drilling depth scale 46 of the cover body C that corresponds to the drilling depth. In this way, the protruding length of the perforation blade body N relative to the idler body F, which is loosely fitted into the tip of the cover body C, can be adjusted, and the perforation depth by the perforation blade body N can be freely adjusted.

[0032] For this reason, when the driving square tube shaft 1 of the center shaft S of the drill body B is inserted into the driving shaft 71 (see Figure 1) of the rotary tool D and the center shaft S is driven to rotate, the rotational force of the driving square tube shaft 1 is transmitted to the drilling blade N and the cover body C via the first rotational force transmission member T1, and the drilling blade N and the cover body C are driven to rotate together. Meanwhile, the idler F loosely fitted at the tip of the cover body C rotates together at a slower rotational speed than the cover body C by irregularly contacting the cover body C as the drilling blade N drills a hole, and just before the drilling is completed, the idler F is pressed in a non-rotating state against the periphery of the circular through hole K drilled in the wall body W by the drilling blade N, preventing damage to the periphery of the circular through hole K.

[0033] 1 and 19, to drill a circular through hole K in the wall W, the drilling blade body N is protruded from the cover body C by a length corresponding to the known wall thickness E of the wall W. When the compression spring 3 is fully extended and the top wall portion 14 of the circular cup portion 12 of the first rotary body transmission member T1 abuts against each of the hook flanges 31b of the pair of rod bodies 31 that make up the second rotary body transmission member T2, the center drill 2 protrudes a predetermined length from the tips of the multiple drilling blades 6 at the tip of the drilling blade body N.

[0034] When the tip of the drilling tool H, which is attached to the drive shaft 71 at the tip of the rotary tool D and is pressed against the wall W while both the drilling blade N and the center drill 2 are rotating, the part of the center drill 2 protruding from the tip of the drilling blade N penetrates into the wall W in a drilling state, as shown in FIG. 20( a), and by maintaining this state, the center of the hole drilled by the drilling blade N immediately afterwards is determined. The center drill 2 penetrates until the pair of clamping block bodies 32 abut against the wall surface of the wall W. When the drilling tool H is continued to be pressed against the wall W by the rotary tool D in this state, the drilling blade N, which rotates integrally with the cover body C, drills the wall W until the idling body F, which is idly fitted around the tip of the cover body C, abuts against the wall surface of the wall W, as shown in FIG. 20( b). This forms a circular through hole K. The idler F comes into contact with the wall surface of the wall W in a non-rotating state just before the boring by the boring blade N is completed, and maintains this state. This prevents the peripheral edge of the boring hole K from being crumbled or damaged.

[0035] When the idler F is in non-rotating contact with the wall W, the cover body C rotates integrally with the perforation blade N relative to the idler F, and therefore, by applying a lubricant such as grease to the idler loose fitting portion 42 of the cover body C, it is possible to reduce the rotational friction caused by the relative rotation between the idler F and the cover body C. A simple bearing can also be used as a means for reducing this rotational friction.

[0036] When the perforation blade N drills the wall W, the driving shaft 1 of the center shaft S and the first torque transmission member T1, which are integrated with the pair of rods 31 of the second torque transmission member T2 and are stopped and not advancing in the drilling direction, advance in the drilling direction, gradually compressing the compression spring 3 of the center shaft S until the compression spring 3 is fully compressed when drilling is complete. When drilling of the circular through hole K is completed by the perforation blade N and the resection block 72 inside the circular through hole K is completely separated from the wall W, as shown in Figure 20(c), the restoring force of the fully compressed compression spring 3 causes the second torque transmission member T2 to move in the drilling direction relative to the perforation blade N and the first torque transmission member T1, which are stopped in the drilling direction, and the resection block 72 is pushed out of the circular through hole K.

[0037] Furthermore, because the perforating blade body N is formed by bending a flat blade plate into an incomplete cylindrical shape, there is a risk that the overall shape will be deformed by the action of centrifugal force and drilling resistance when the perforating blade body N is driven to rotate, but the idler loose fitting portion 42 at the tip of the cover body main body 41 of the cover body C is formed with a smaller diameter than the cover body main body 41, and is positioned inside the cover body C, and the two are assembled together in a state close to the outer circumferential surface of the perforating blade body N which rotates integrally with the cover body C. Therefore, the incomplete cylindrical perforating blade body N maintains its original shape without any partial deformation of its overall shape even when driven to rotate, allowing for smooth drilling.

[0038] Furthermore, the contact portion 52 provided at the tip of the idling body F and contacting the wall body W is positioned as close as possible to the perforation blade body N while avoiding contact with the perforation blade body N, as shown in Figures 20(b) and (c). Therefore, just before the perforation blade body N finishes perforating the wall body W, the contact portion 52 can be positioned near the periphery of the perforated circular through hole K, enabling stable perforation work.

[0039] In addition, in the above embodiment, the cover body C is integrally attached to the first rotational force transmission member T1, which transmits the rotational force of the driving square tube shaft 1 of the center shaft portion S to the perforation blade body N, but it is also possible to integrally attach the cover body C to the perforation blade body N itself by providing a cover body attachment portion integrally with the perforation blade body N. [Explanation of symbols]

[0040] C: Cover body D: Rotary tools F: Idler G: Fixture K: Circular through hole N: Perforating blade S: Center shaft T1: First rotational force transmission member (rotational force transmission member) T2: Second rotational force transmission member W: Wall (perforated body) 1: Drive square tube shaft 2: Center drill 41: Cover body 42: Idler loose fitting part 52: Contact part (idling body)

Claims

1. a center shaft portion having a center drill for drilling the center of the circular through hole before drilling the circular through hole; a perforating blade body that is disposed outside the center shaft portion and is driven to rotate by a rotational force of the center shaft portion transmitted thereto via a rotational force transmission member, A drilling tool attached to a rotary tool for drilling a circular through hole in a workpiece, a cover body that is attached integrally to the rotational force transmission member or the perforation blade body so as to rotate together with the rotational force transmission member or the perforation blade body and is disposed on the entire outer side of the perforation blade body; an idler body that is supported on the cover body at an end of the cover body on the side of the perforation blade of the perforation blade body in a state of protruding from the end and that can idle relative to the cover body, and that abuts non-rotatably on the peripheral portion of the circular through-hole of the object to be perforated; A perforating tool comprising:

2. 2. The drilling tool according to claim 1, wherein the idler body is annular and has an inner diameter larger than an inner diameter of the cover body.

3. The punch according to claim 2, wherein the idler body is fitted onto the cover body at an end of the punch blade body on the punch blade side.

4. the center shank portion is assembled to a drive square tube shaft so that a center drill can move in and out of the drive square tube shaft, and the rotational force of the center shank portion is transmitted to the drill blade body via the rotational force transmission member that is fitted non-rotatably on the drive square tube shaft; 4. The drilling tool according to claim 1, wherein the cover body is integrally assembled with the rotational force transmission member so that its position along the drilling direction can be adjusted relative to the rotational force transmission member.

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