JP7049942B2 - Dust absorption bit co-rotation prevention attachment, hammer drill - Google Patents

Description

The present invention relates to a dust suction bit used when performing a drilling operation using a power tool, and a hammer drill equipped with the dust suction bit.

When drilling a hole in concrete or stone using an electric tool, a drill bit is attached to an electric drill or the like and the drill bit is rotated to perform drilling work. At this time, in order to prevent the generated dust from scattering, Patent Document 1 provides a dust suction path in the bit body, one end of the dust suction path is opened to the tip of the bit body, and the other end is the side surface of the intermediate portion of the bit body. A dust-absorbing bit is disclosed in which a dust-absorbing adapter (hose attachment portion) covering the opening is mounted on the bit body by opening the bit. By connecting the dust collecting adapter to the dust collector via a hose, the dust is sucked from the tip of the dust collecting bit and passed through the dust collecting path, and the dust can be collected from the dust collecting adapter.

Japanese Patent No. 5939615

However, in the above-mentioned conventional dust-absorbing bit, the hose mounting portion is merely covered with the bit body in a sealed state. Therefore, when the bit body rotates, the hose mounting portion rotates due to the friction between the bit body and the hose mounting portion. A urging force is applied, and the hose attachment part tries to rotate (co-rotate) with the hose connected. Therefore, the hose may get entangled with the power tool or the operator and reduce workability.

Therefore, an object of the present invention is to provide a co-rotation prevention attachment capable of effectively suppressing co-rotation of the hose attachment portion of the dust suction bit, and a hammer drill using the co-rotation prevention attachment.

In order to achieve the above object, the invention according to claim 1 is to use a dust collecting bit which is attached to the front end of a power tool and has a hose mounting portion for attaching a hose for collecting dust. It is a co-rotation prevention attachment to regulate the rotation of the hose attachment part due to rotation.
A ring-shaped joint attached to the tubular housing of a power tool ,
Includes a pair of left and right arm portions that form an inverted L-shape that bends forward after protruding downward from the lower surface of the joint portion at predetermined intervals to the left and right.
With the joint portion coupled to the housing , the arm portion sandwiches the hose attachment portion from the left and right to regulate the movement of the hose attachment portion in the rotational direction.
The invention according to claim 2 is characterized in that, in the configuration of claim 1, the coupling portion can be attached to the housing in a plurality of orientations in the axial direction of the dust collecting bit.
In order to achieve the above object, the invention according to claim 3 comprises a hose attachment portion for attaching a hose for collecting dust, and when using a dust absorbing bit attached to the front end of a power tool equipped with a side handle. In addition, it is a co-rotation prevention attachment to regulate the rotation of the hose attachment part with the rotation of the dust suction bit.
A ring-shaped joint that is attached to the side handle and allows power tools to penetrate ,
Includes a pair of left and right arm portions that form an inverted L-shape that bends forward after protruding downward from the lower surface of the joint portion at predetermined intervals to the left and right.
It is characterized in that the arm portion holds the hose attachment portion from the left and right to regulate the movement of the hose attachment portion in the rotational direction in a state where the joint portion through which the power tool is penetrated is connected to the side handle .
The invention according to claim 4 is characterized in that, in the configuration of claim 3 , the side handle can change the direction of the dust suction bit in the axial direction while being coupled to the power tool .
In order to achieve the above object, the invention according to claim 5 is a hammer drill, which is equipped with a dust absorbing bit provided with a hose attachment portion for attaching a hose for collecting dust, and claims 1 to 4 . It is characterized in that the rotation of the hose attachment portion can be regulated by providing the co-rotation prevention attachment described in any of the above.

According to the inventions of claims 1 , 3 and 5 , the hose is sandwiched between the joint portion to be connected to the power tool or the side handle and the hose attachment portion from the left and right while the joint portion is connected to the power tool or the side handle. By providing a pair of arms that regulate the movement of the mounting portion in the rotation direction, it is possible to effectively suppress the co-rotation of the hose mounting portion of the dust suction bit.
In particular, according to the third aspect of the present invention, by connecting the connecting portion to the side handle mounted on the power tool, the side handle is used to prevent co-rotation even when the connecting portion cannot be connected to the housing of the power tool. Can be securely attached.
Further, since the rotation of the hose attachment portion is restricted by the pair of arms, it is possible to easily suppress the co-rotation of the hose attachment portion.
According to the second aspect of the present invention, in addition to the above effect, the joint portion can be attached to the housing in a plurality of orientations in the axial direction of the dust absorbing bit, so that the joint portion can be attached to the housing in accordance with the orientation of the hose attachment portion. The orientation of the co-rotation prevention attachment can be properly selected and attached.
According to the invention of claim 4 , in addition to the above effect, the side handle can change the direction of the dust suction bit in the axial direction while being coupled to the power tool, so that the direction of the hose attachment portion can be changed. At the same time, the orientation of the co-rotation prevention attachment can be changed together with the side handle , improving usability.

It is a perspective view of the hammer drill using the co-rotation prevention attachment of Form 1. FIG. It is a central vertical sectional view of a hammer drill using the co-rotation prevention attachment of Form 1 (the bit body is omitted). FIG. 2 is an enlarged cross-sectional view taken along the line AA of FIG. It is a perspective view of the co-rotation prevention attachment of Form 1. FIG. In the explanatory view of the co-rotation prevention attachment of the first embodiment, (A) shows a flat surface, (B) shows a side surface, and (C) shows a back surface. It is a perspective view of the hammer drill using the co-rotation prevention attachment of the 2nd form. It is a central vertical sectional view of a hammer drill using the co-rotation prevention attachment of the second form (the bit body is omitted). FIG. 7 is an enlarged cross-sectional view taken along the line BB of FIG. It is a perspective view of the co-rotation prevention attachment of the 2nd form. In the explanatory view of the co-rotation prevention attachment of the second embodiment, (A) shows a flat surface, (B) shows a side surface, and (C) shows a back surface. FIG. 3 is a perspective view of a hammer drill using the co-rotation prevention attachment of the third embodiment. It is a central vertical sectional view of a hammer drill using the co-rotation prevention attachment of the third form (the bit body is omitted). FIG. 12 is an enlarged cross-sectional view taken along the line CC of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Form 1]
FIG. 1 is a perspective view showing an example of a hammer drill equipped with a dust suction bit and an attachment for preventing co-rotation thereof, and FIG. 2 is a central vertical sectional view.
First, the dust suction bit 1 includes a metal bit body 2 and an elastically deformable resin hose attachment portion 3 mounted on the bit body 2. The bit body 2 has a blade portion 4 having a cutting edge 5 at the front end, an intermediate portion 6 having a larger diameter axis than the blade portion 4 formed coaxially to the rear of the blade portion 4, and a coaxial portion to the rear of the intermediate portion 6. It is formed of a shank portion 7 having a diameter smaller than that of the intermediate portion 6. The hose mounting portion 3 is mounted orthogonally to the intermediate portion 6.

A dust suction path 8 is formed at the axial center of the blade portion 4 and the intermediate portion 6 so as to straddle both of them. The front end of the dust suction path 8 in the blade portion 4 is bifurcated and extends forward, and a pair of suction ports 9 and 9 are opened in the front end surface of the blade portion 4. The rear end of the dust suction path 8 is bent outward in the radial direction in the intermediate portion 6 so that the outlet 10 is opened on the side surface of the intermediate portion 6.
The intermediate portion 6 has a front flange 11 and a rear flange 12 for positioning the front and rear end faces of the hose mounting portion 3 on the outer periphery near both front and rear ends.
At the rear end of the shank portion 7, a pair of left and right retaining recesses (not shown) for inserting and mounting into the tool holder 28 of the hammer drill 20, which will be described later, and a pair of upper and lower detent grooves 13 and 13, respectively, are formed. There is.
The hose attachment portion 3 is connected to a cylindrical exterior portion 14 that is externally rotatable relative to the intermediate portion 6 between the front flange 11 and the rear flange 12, and is connected to the exterior portion 14 and protrudes outward in the radial direction. It is composed of a tubular portion 15 having an open tip surface. The portion of the exterior portion 14 that is connected to the tubular portion 15 is opened to communicate with the tubular portion 15 and the outlet 10 of the intermediate portion 6 is opened into the tubular portion 15.

The hammer drill 20 houses the motor 22 in the rear portion of the cylindrical housing 21 extending in the front-rear direction with the output shaft 23 facing forward. An intermediate shaft 24 that is rotationally transmitted from the output shaft 23 is supported in the front-rear direction in front of the motor 22, and the intermediate shaft 24 is provided with a first gear 25, clutches 26, 26, and a boss sleeve 27 from the front. There is. Above the intermediate shaft 24, a cylindrical tool holder 28 into which a bit can be inserted into the tip thereof is axially supported in parallel with the intermediate shaft 24. A piston cylinder 29 is loosely inserted into the tool holder 28 from the rear, and an upper end of an arm 31 exteriorized via a swash bearing 30 is connected to a boss sleeve 27 at the rear end of the piston cylinder 29. Inside the piston cylinder 29, a striker 33 is movably mounted on the inside via an air chamber 32 so as to be able to hit an impact bolt 34 provided in front of the striker 33. The first gear 25 meshes with the second gear 35 mounted on the tool holder 28. The front end of the tool holder 28 projects forward from the housing 21, and the bit can be attached and detached by the operation sleeve 36 externally attached to the front end.

At the front end of the housing 21, behind the operation sleeve 36, a disk portion 37 having a diameter slightly larger than that of the operation sleeve 36 is formed. As shown in FIG. 3, a plurality of notches 38, 38. Are formed on the outer peripheral surface of the disk portion 37 at positions shifted vertically by 45 ° from both the left and right sides and 45 ° from the left and right sides, respectively. There is.

On the other hand, a handle 39 having a switch 40 and a switch lever 41 is formed downward at the rear end of the housing 21.
Further, a switching knob 42 for switching the operation mode is provided on the lower surface of the housing 21. Here, the clutches 26 and 26 are slid by operating the switching knob 42 to engage only with the first gear 25, engage only with the boss sleeve 27, and simultaneously with the first gear 25 and the boss sleeve 27. By selecting one of the engaged states, the tool holder 28 rotates via the second gear 35 to rotate the bit, and the piston cylinder 29 is reciprocated and interlocked by the swing of the arm 31. The striker 33 makes it possible to select a hammer mode in which the bit is hit through the impact bolt 34 and a hammer drill mode in which the rotation of the tool holder 28 and the hitting of the impact bolt 34 are performed at the same time.
At the front end of the housing 21, behind the disk portion 37, a side handle 43 including a clamp portion 44 that clamps the front end of the housing 21 and a grip portion 47 that protrudes outward from the clamp portion 44 is mounted.

The co-rotation prevention attachment 50 is a resin molded product, and as shown in FIGS. A pair of left and right arm parts 52, 52 as an inverted L-shaped engaging part that bends forward after protruding at a predetermined interval, and an arm part between the arm parts 52, 52 except for the tip part. It is provided with a connecting plate 53 that connects 52 and 52 to each other. The joint portion 51 is formed in a two-step diameter having a larger diameter at the rear end than the front side, and has a semicircular cross section extending in the front-rear direction on both left and right sides on the inner circumference of the large diameter portion 54 at the rear end. Engagement protrusions 55, 55 are formed. Further, stoppers 56, 56, ... Are provided on the inner circumference of the rear end of the coupling portion 51 at equal intervals in the circumferential direction.

The co-rotation prevention attachment 50 configured as described above has the large-diameter portion 54 of the joint portion 51 from the front of the housing 21 of the hammer drill 20 with the arms portions 52 and 52 facing forward, and the engagement protrusion on the inner circumference. The 55, 55 is attached to the disk portion 37 in a phase aligned with the left and right notches 38, 38 of the disk portion 37, and the stoppers 56, 56 ... Are pushed in until they get over the rear side of the disk portion 37. Then, the co-rotation prevention attachment 50 is in a state of being stopped by the engagement between the engaging protrusions 55, 55 and the notches 38, 38, and the stoppers 56, 56, ... Are locked to the disk portion 37 from the rear. By doing so, it is connected in a state where it is prevented from coming off forward.
In this state, the dust suction bit 1 is placed in a downward state in which the tubular portion 15 of the hose attachment portion 3 is located between the arm portions 52 and 52, and the shank portion 7 is inserted into the tool holder 28 and attached by the operation sleeve 36. The bit 1 is mounted in a state where the tubular portion 15 is sandwiched between the arm portions 52 and 52 and the hose attachment portion 3 is prevented from rotating. A flexible hose (not shown) connected to the dust collector is connected to the tubular portion 15.

Then, with the hammer drill mode (or drill mode) selected, the tip of the blade 4 is set at the anchor bolt driving position on the floor, ceiling, etc., and the switch lever 41 of the hammer drill 20 is pushed in to operate the switch 40. When turned on, the motor 22 is driven, the intermediate shaft 24 is rotated, and the tool holder 28 is rotated. Therefore, the bit body 2 of the dust suction bit 1 rotates together with the tool holder 28, and drilling by the blade portion 4 becomes possible.
When the dust collector is operated during the drilling work, the generated dust is sucked together with the outside air from the suction ports 9 and 9 on the front end surface of the cutting edge 5, and as it is, it passes through the dust suction path 8 and is passed through the dust suction path 8 from the outlet 10 to the tubular portion of the hose attachment portion 3. When it reaches 15, dust is collected from the flexible hose to the dust collector. Therefore, the drilling work can be performed without leaving dust in the formed pilot hole.

At this time, as the bit body 2 rotates, a rotational urging force is applied to the hose attachment portion 3 due to friction with the bit body 2, but the hose attachment portion 3 is sandwiched by the arm portions 52 and 52 of the co-rotation prevention attachment 50. Therefore, the rotation with the bit body 2 is restricted.
If it is desired to change the direction of the hose attachment portion 3 (direction in which the flexible hose is routed) according to the work, the joint portion 51 of the co-rotation prevention attachment 50 also matches the direction of the hose attachment portion 3 and is the shaft of the dust suction bit 1. If the orientation in the circumferential direction is changed, the engaging protrusions 55 and 55 engage with any of the notches 38 provided in the disk portion 37, so that the connecting portion 51 can be fixed at the selected rotational position.

As described above, according to the co-rotation prevention attachment 50 and the hammer drill 20 of the first embodiment, the hose attachment portion is in a state where the coupling portion 51 coupled to the hammer drill 20 side and the coupling portion 51 are coupled to the hammer drill 20 side. By providing an engaging portion (arm portions 52, 52) that engages with 3 and regulates the movement of the hose mounting portion 3 in the rotation direction, the co-rotation of the hose mounting portion 3 of the dust suction bit 1 is effectively performed. It can be suppressed.
In particular, here, since the coupling portion 51 is directly coupled to a part (housing 21) of the hammer drill 20, the co-rotation prevention attachment 50 can be reliably attached.
Further, since the engaging portion is a pair of arm portions 52, 52 that sandwich the hose attachment portion 3, it is possible to easily suppress the co-rotation of the hose attachment portion 3.
Further, since the coupling portion 51 can be attached in a plurality of directions in the axial direction of the dust suction bit 1, the orientation of the co-rotation prevention attachment 50 can be appropriately selected and attached according to the orientation of the hose attachment portion 3. ..

In the first embodiment, the connecting portion and the engaging portion are not limited to the above structure, and the number and shape of the engaging protrusions can be changed in the connecting portion and the number and shape of the notches can be changed in the disk portion. In addition, the disc portion may be eliminated and the joint portion may be attached by tightening with a band or a screw. Further, the coupling portion may be coupled to the rear side of the front end of the housing.
Furthermore, the engaging part is a plate with a notch or a through hole at the tip where the hose attachment part engages instead of the arm part, in addition to a design change such as lengthening the arm part and bending the tip in a facing shape. It may be a shape or a rod.

Next, another embodiment of the present invention will be described. However, since the configurations of the dust suction bit 1 and the hammer drill 20 are substantially the same as those of the first embodiment, the same components are designated by the same reference numerals and overlapping description will be omitted.
[Form 2]
As shown in FIGS. 6 and 7, the coupling portion 51 of the co-rotation prevention attachment 50A used here is coupled to the side handle 43 instead of the housing 21 of the hammer drill 20. As shown in FIG. 8, the side handle 43 includes a C-shaped clamp portion 44 that exteriors the front portion of the housing 21, a cylinder portion 45, 45 coaxially provided at both ends of the clamp portion 44, and a cylinder portion 45. It consists of a bolt 46 penetrating the 45 from the right side and a grip portion 47 rotatably inserted into the cylinder portion 45 on the left side while holding the nut 48 into which the bolt 46 is screwed. Therefore, when the grip portion 47 is rotated in the tightening direction of the nut 48 with the clamp portion 44 exteriorized on the front portion of the housing 21, the tubular portions 45 and 45 approach each other and the clamp portion 44 tightens the housing 21. Can be clamped. On the contrary, when the grip portion 47 is rotated in the direction in which the nut 48 is loosened, the cylinder portions 45 and 45 are separated from each other, the tightening of the housing 21 by the clamp portion 44 is released, and the grip portion 47 is rotated to an arbitrary angle. The side handle 43 can be removed.

As shown in FIGS. It can be elastically fitted to 45 and 45 from the front. On the inner surface (rear surface) of the fitting cylinder 60, a flat surface portion 61 that abuts on a flat surface provided on the front surface of the cylinder portions 45, 45 is formed.
Further, a semicircular band-shaped receiving portion 62 to which the lower portion of the clamp portion 44 of the side handle 43 is fitted is formed in the lower portion of the connecting portion 51, and the clamp portions are formed on the left and right ends of the receiving portion 62 at the rear end edges. The stoppers 63 and 63 that engage with the back surface of the 44 are formed.
The housing 21 here is not provided with the disk portion 37 as in the first embodiment, and the inner diameter of the joint portion 51 is larger than the outer diameter of the housing 21.

In the co-rotation prevention attachment 50A configured as described above, the joint portion 51 is attached to the housing 21 from the front of the housing 21 of the hammer drill 20 equipped with the side handle 43, with the arms 52 and 52 facing forward. Then, the fitting cylinder 60 is fitted to the cylinder portions 45, 45 of the side handle 43 from the front, and the receiving portion 62 is fitted to the lower part of the clamp portion 44, and the stoppers 63, 63 are rear of the clamp portion 44. Push it in until you get over it. Then, the coupling portion 51 is prevented from rotating forward by fitting the fitting cylinder 60 and the cylinder portions 45, 45, and the stoppers 63, 63 are locked to the clamp portion 44 from the rear. It is coupled to the clamp portion 44 in the closed state.

In this state, the dust suction bit 1 is placed in a downward state in which the tubular portion 15 of the hose attachment portion 3 is located between the arm portions 52 and 52, and the shank portion 7 is inserted into the tool holder 28 and attached by the operation sleeve 36. The bit 1 is mounted in a state where the tubular portion 15 is sandwiched between the arm portions 52 and 52 and the hose attachment portion 3 is prevented from rotating.
Therefore, even if the bit main body 2 is rotated by performing the drilling work with the dust suction bit 1, the hose attachment portion 3 does not rotate together with the bit main body 2.
If you want to change the direction of the hose attachment part 3 (the direction in which the flexible hose is routed) according to the work, loosen the clamp part 44 by operating the grip part 47 and change the side handle 43 to the direction of the hose attachment part 3. If the hose is rotated in accordance with the above, the co-rotation prevention attachment 50A also rotates integrally with the side handle 43, so that it can be fixed at the selected rotation position.

As described above, also in the co-rotation prevention attachment 50A and the hammer drill 20 of the second embodiment, the coupling portion 51 coupled to the side handle 43 on the hammer drill 20 side and the coupling portion 51 are coupled to the hammer drill 20 side. By providing an engaging portion (arms 52, 52) that engages with the hose mounting portion 3 to regulate the movement of the hose mounting portion 3 in the rotational direction, the hose mounting portion 3 of the dust suction bit 1 rotates together with the hose mounting portion 3. Can be effectively suppressed.
In particular, here, since the coupling portion 51 is coupled to the side handle 43 attached to the hammer drill 20, even if the coupling portion 51 cannot be coupled to the housing 21, the side handle 43 is used to securely attach the co-rotation prevention attachment 50A. It will be possible.
Further, since the joint portion 51 can change the direction of the dust suction bit 1 in the axial direction with the side handle 43 in a state of being coupled to the side handle 43, the co-rotation prevention attachment 50 is matched with the direction of the hose attachment portion 3. The orientation of the hose can be changed together with the side handle 43, which improves usability.

Even in this form 2, the shapes of the connecting portion and the engaging portion can be changed as appropriate, and the connecting portion may be changed according to the shape of the side handle, and is formed so as to fit only in the clamp portion instead of the tubular portion. You may. The side handle is not limited to a shape having a single grip portion, and even if a loop-shaped grip portion is provided, it is possible to attach a co-rotation prevention attachment.

[Form 3]
The co-rotation prevention attachment 50B shown in FIGS. 11 to 13 is integrally provided with the hose attachment portion 3. That is, a coupling arm 65 as a coupling portion integrally formed on the rear surface of the tubular portion 15 of the hose mounting portion 3 and extending rearward, and a U-shaped engaging portion in a plan view integrally formed on the rear end of the coupling arm 65. The grip portion 66 is fitted to the lower front surface of the housing 21 in a state where the dust suction bit 1 is attached to the hammer drill 20, so that the hose attachment portion 3 rotates via the coupling arm 65. It regulates.
Therefore, even if the bit main body 2 is rotated by performing the drilling work with the dust suction bit 1, the hose attachment portion 3 is prevented from rotating together with the bit main body 2.

As described above, also in the co-rotation prevention attachment 50B and the hammer drill 20 of the above-mentioned embodiment 3, the coupling arm 65 coupled to the hose mounting portion 3 and the housing 21 of the hammer drill 20 are engaged with each other to rotate the hose mounting portion 3. By providing the engaging portion (grip portion 66) that regulates the movement in the direction, it is possible to effectively suppress the co-rotation of the hose attachment portion 3 of the dust suction bit 1.
In particular, here, since the coupling portion is a coupling arm 65 that is integrally coupled to the hose attachment portion 3, the hose attachment portion 3 is also used as the co-rotation prevention attachment 50B, which is a rational configuration.

The shape of the engaging portion is not limited to the U-shaped grip portion in the plan view of the third aspect, and can be appropriately changed according to the form of the housing. It is also possible to engage the engaging portion with a side handle or the like instead of the housing.
Further, in the above-described third form, the coupling arm is provided integrally with the hose mounting portion, but the coupling arm is provided with a hose mounting portion by providing a ring portion or a tubular portion exterior to the hose mounting portion at the front end of the coupling arm. It may be provided separately.

In addition, the present invention can be applied to the structure of the dust absorbing bit, which is common to each form, even if the blade portion is short or the position and shape of the hose mounting portion are different.
On the other hand, the form of the hammer drill is also the direction and type of the motor (for example, the arrangement with the output shaft facing upward), the type (for example, a brushless motor), the internal mechanism such as a striking mechanism (for example, the one using a crank mechanism or the one without an impact bolt). , Power supply (with battery pack), etc. can be changed as appropriate.

1 ... Dust suction bit, 2 ... Bit body, 3 ... Hose mounting part, 4 ... Blade part, 6 ... Middle part, 7 ... Shank part, 8 ... Dust suction path, 9 ... Suction port, 10・ ・ Exit, 14 ・ ・ Exterior, 15 ・ ・ Cylindrical part, 20 ・ ・ Hammer drill, 21 ・ ・ Housing, 22 ・ ・ Motor, 23 ・ ・ Output shaft, 24 ・ ・ Intermediate shaft, 28 ・ ・ Tool holder , 37 ... disk part, 38 ... notch, 43 ... side handle, 44 ... clamp part, 45 ... cylinder part, 50, 50A, 50B ... co-rotation prevention attachment, 51 ... joint part, 52 ... Arm, 55 ... Engagement protrusion, 56, 63 ... Stopper, 60 ... Fitting cylinder, 62 ... Receiving part, 65 ... Coupling arm, 66 ... Grip part.

Claims (5)

When using a dust collecting bit that is equipped with a hose mounting part for attaching a dust collecting hose and is mounted on the front end of a power tool, co-rotation for restricting the rotation of the hose mounting part with the rotation of the dust collecting bit. It ’s a preventive attachment,
A ring-shaped joint attached to the tubular housing of the power tool ,
Includes a pair of left and right arm portions in an inverted L shape that protrudes downward from the lower surface of the joint portion at predetermined intervals and then bends forward.
A co-rotation prevention attachment characterized in that, in a state where the joint portion is coupled to the housing , the arm portion sandwiches the hose attachment portion from the left and right to regulate the movement of the hose attachment portion in the rotational direction. The co-rotation prevention attachment according to claim 1 , wherein the coupling portion can be attached to the housing in a plurality of directions in the axial direction of the dust suction bit. A hose mounting part for attaching a dust collecting hose is provided, and when using a dust collecting bit mounted on the front end of a power tool equipped with a side handle, the rotation of the hose mounting part due to the rotation of the dust collecting bit is restricted. It is a co-rotation prevention attachment for
A ring-shaped joint attached to the side handle and through which the power tool can penetrate ,
Includes a pair of left and right arm portions in an inverted L shape that protrudes downward from the lower surface of the joint portion at predetermined intervals and then bends forward.
It is characterized in that the arm portion sandwiches the hose attachment portion from the left and right to regulate the movement of the hose attachment portion in the rotational direction in a state where the joint portion through which the power tool is penetrated is connected to the side handle. Co-rotation prevention attachment. The co-rotation prevention attachment according to claim 3 , wherein the side handle can change the direction of the dust suction bit in the axial direction while being coupled to the power tool . A dust suction bit provided with a hose attachment portion for attaching a dust collecting hose is attached, and the co-rotation prevention attachment according to any one of claims 1 to 4 is provided to regulate the rotation of the hose attachment portion. A hammer drill characterized by the fact that it was done.

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