Dust collection cups and power tools

Abstract

To achieve compactification of a dust collection part to secure good visibility even if a connection port is provided at a dust collection cup.SOLUTION: A dust collection cup 1 includes a connection port 17 of a flexible hose 31 at the radial outer side of a bit B and the rear relative to a seal plate 8 on an outer peripheral surface of an attachment part 2. The connection port 17 is disposed at a position such that a distance D1 from an axis A1 of the attachment part 2 to a point P1 at an outermost position from the axis A1 in a radial direction is longer than a distance D2 from the axis A1 to a point P2 on an outer peripheral surface of the attachment part 2, which is located at the opposite side of the point P1 across the axis A1 in the radial direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a dust collection cup that is attached to a power tool such as a hammer drill for dust collection, and to a power tool equipped with the dust collection cup. [Background technology]

[0002] In power tools such as hammer drills, a dust collection cup is attached to the tip to prevent dust generated from the workpiece from scattering when a bit attached to the tip is rotated to perform drilling or other operations. As disclosed in Patent Document 1, for example, this dust collection cup has a cylindrical attachment part attached to the tip of the power tool and a bellows-shaped dust collection part attached to the front of the attachment part and surrounding the bit. The attachment part has a connection port for connecting a flexible hose of an external dust collector or the like. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5575428 Summary of the Invention [Problem to be solved by the invention]

[0004] In this dust collection cup, a seal is provided between the mounting portion and the dust collection portion, sealing the two apart from the through-hole of the bit. Therefore, the mounting portion has a large-diameter attachment portion that forms a connection port radially outward and rearward of the seal portion, and the dust collection portion is attached coaxially to the attachment portion. This results in the outer diameter of the dust collection portion being larger than the mounting portion, which increases the size of the dust collection cup and can impair visibility during work.

[0005] Therefore, an object of the present disclosure is to provide a dust collection cup and a power tool that can make the dust collection section compact even when a connection port is provided, and can ensure good visibility. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the present disclosure provides a dust collection cup that can be attached to a power tool and has a cylindrical attachment portion through which a bit attached to the power tool passes when attached in the attached state, and a cylindrical dust collection portion provided in front of the attachment portion and through which the bit passes, and a sealing portion with a through hole for the bit is provided between the attachment portion and the dust collection portion, and a connection port for a dust collection hose is provided radially outside and rearward of the sealing portion on the outer peripheral surface of the attachment portion. The mounting part and the dust collecting part have circular cross sections, and the portion of the mounting part where the connection port is formed is eccentric from the axis of the mounting part toward the connection port side, The connection port is arranged at a position where the distance from the axis to its outermost position in the radial direction is longer than the distance from the axis to the outer circumferential surface of the attachment part located on the opposite side of the axis in the radial direction. 。 The rear end of the dust collecting unit is provided with a large diameter portion that is larger in diameter than the front portion of the dust collecting unit and that is connected to the front end of the mounting unit including the portion where the connection port is formed, and the connection port is in communication with the mounting unit and the dust collecting unit. It is characterized by: [Effects of the Invention]

[0007] According to the present disclosure, the connection port alone can be positioned away from the axis of the mounting part, and the dust collection part can be formed to fit the mounting part excluding the portion where the connection port is formed. Therefore, even with the connection port, the dust collection part can be made compact and good visibility can be ensured. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of a hammer drill with a dust collection cup attached. [Figure 2] FIG. 2 is a central longitudinal cross-sectional view of a hammer drill with a dust collection cup attached. [Figure 3] 3A is an enlarged view of the front portion of FIG. 2, and FIG. 3B is a cross-sectional view taken along line AA. [Figure 4] FIG. 2 is an exploded perspective view of the dust cup from the front. [Figure 5] FIG. 2 is an exploded perspective view of the dust cup from the rear. [Figure 6] 6A and 6B are explanatory views showing the state in which the attachment part and the dust collecting part are separated, with FIG. 6A showing a side view and FIG. 6B showing a cross section taken along line BB. [Figure 7]7A and 7B are explanatory views showing the state in which the mounting part and the dust collecting part are combined, with FIG. 7A showing a side view and FIG. 7B showing a cross section taken along line CC. [Figure 8] 8A and 8B are explanatory views showing the state in which the attachment part and the dust collecting part are connected, with FIG. 8A showing a side view and FIG. 8B showing a cross section taken along line DD. [Figure 9] 9A and 9B are explanatory views showing a state in which a dust collecting cup is attached to a hammer drill, with FIG. 9A showing an enlarged central longitudinal cross section of the front part, and FIG. 9B showing a cross section taken along line EE. [Figure 10] 10A and 10B are explanatory views showing a state in which the dust collecting cup is combined with a hammer drill, in which FIG. 10A shows an enlarged central longitudinal section of the front part, and FIG. 10B shows a section taken along line FF. [Figure 11] FIG. 11A shows an enlarged central longitudinal section of the front part of a hammer drill with a flexible hose connected to a dust collection cup, and FIG. 11B shows a GG section. [Figure 12] FIG. 10 is a perspective view of a hammer drill equipped with a dust collection cup according to a modified example. [Figure 13] FIG. 13A shows an enlarged central vertical cross section of the front part of a hammer drill equipped with a modified dust collecting cup, and FIG. 13B shows a cross section taken along line HH. DETAILED DESCRIPTION OF THE INVENTION

[0009] In one embodiment of the present disclosure, the dust collecting unit may be detachable from the mounting unit. This configuration allows the dust collecting unit to be easily replaced if damaged. Also, by preparing a plurality of dust collecting units with different shapes to suit different tasks, the dust collecting unit can be easily selected and used. In one embodiment of the present disclosure, the mounting portion and the dust collecting portion may have circular cross sections, and a portion of the mounting portion where the connection port is formed may be provided eccentrically from the axis toward the connection port. With this configuration, the connection port alone can be easily positioned at a position away from the axis of the mounting portion. In one embodiment of the present disclosure, the mounting portion and the dust collecting portion may be bayonet-coupled, and may be biased in the coupling direction with respect to each other in this coupled state. With this configuration, the dust collecting section can be easily attached and detached, and a stable connection state can be maintained.

[0010] In one embodiment of the present disclosure, the mounting portion may be provided with a receiving portion that abuts against the periphery of the opening at the rear end of the dust collecting portion and supports the dust collecting portion evenly in the circumferential direction. With this configuration, the pressure applied to the dust collecting portion during use can be received in the axial direction, making it less likely for the dust collecting portion to tilt. The receiving portion also ensures an air passage. In one embodiment of the present disclosure, the receiving portion may also serve as a positioning portion for the sealing portion. This configuration is rational and allows for a reduction in the number of parts. In one embodiment of the present disclosure, the mounting portion may be detachable from the power tool by a bayonet coupling. This configuration allows easy selection of whether to use the dust collection cup as needed. In one embodiment of the present disclosure, the mounting portion may be mountable to the power tool at a plurality of selectable positions around the axis of the bit. With this configuration, the orientation of the connection port can be selected to suit the task at hand. [Example]

[0011] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a perspective view showing an example of a dust collection cup and a hammer drill, which is an example of a power tool equipped with the dust collection cup. Fig. 2 is a central longitudinal cross-sectional view of the hammer drill equipped with the dust collection cup. Fig. 3 is an enlarged view of the front part of Fig. 2 and a cross-sectional view taken along line AA. The dust collection cup 1 comprises a rear mounting portion 2 and a front dust collection portion 3. The mounting portion 2 is cylindrical and made of resin, and is attached to the front tube portion 47 of the hammer drill 40. The dust collection portion 3 is cylindrical and made of resin with a thinner wall than the mounting portion 2, and is connected to the front end of the mounting portion 2. 4 and 5, four pairs of protrusions 4, 4 that protrude toward the center are provided at equal intervals in the circumferential direction on the inner periphery of the rear end of the mounting part 2. Four elongated holes 5, 5... that extend in the circumferential direction are formed in front of the protrusions 4, 4 at the rear end of the mounting part 2. A pair of windows 6, 6 are formed in the circumferential surface of the mounting part 2 in front of the elongated holes 5.

[0012] The front end 7 of the mounting portion 2 is formed with a front end portion 7 that tapers forward. A seal plate 8 is provided at the front end 7. The seal plate 8 includes a disk portion 9 and a tapered portion 10. The disk portion 9 is circular in front view and fits into the opening of the front end 7. A circular through-hole 11 is formed in the center through which the bit B passes. The tapered portion 10 widens from the outer periphery of the rear surface of the disk portion 9 toward the rear. Four front bearing portions 12, 12·· are provided at equal intervals around the periphery of the front end 7. Each front bearing portion 12 protrudes forward beyond the front surface of the front end 7, then protrudes toward the center of the front end 7, abutting or adjacent to the front surface of the disk portion 9. Four rear bearing portions 13, 13·· are provided at the inner periphery of the mounting portion 2, rearward of the front bearing portions 12, in the same phase as the front bearing portions 12. Each rear receiving portion 13 protrudes toward the center of the mounting portion 2 and abuts against the rear end of the tapered portion 10. Therefore, the sealing plate 8 is positioned at the front end of the mounting portion 2 and closes the opening of the front end portion 7 except for the through hole 11.

[0013] An attachment portion 15 of the dust collection unit 3 is integrally formed at the front of the attachment portion 2. The attachment portion 15 is a circular ring-shaped attachment portion with a larger diameter than the front end portion 7. The attachment portion 15 is disposed at a position where its axis A2 is eccentric from the axis A1 of the attachment portion 2 in the radial direction of the attachment portion 2 (the radial direction of the bit B). Due to this eccentricity, as shown in FIG. 6, the front end portion 7 partially overlaps with the attachment portion 15. A closing portion 16 is formed at the rear of the attachment portion 15. The closing portion 16 is provided with a connection port 17 that opens obliquely rearward with respect to the axis A2 of the attachment portion 15. As shown in FIG. 3, point P1, which is the outermost position of the connection port 17 in the radial direction of the bit B, is located on a straight line L in the radial direction where the attachment portion 15 is eccentric from the axis A1 in a front view. In the direction of this straight line L, a distance D1 from the axis A1 of the mounting part 2 to point P1 is longer than a distance D2 from the axis A1 to point P2 on the outer surface of the mounting part 2 located on the opposite side of the axis A1 from point P1. The closing part 16 is provided with a tubular part 18 that is concentric with the connection port 17 and protrudes obliquely rearward from the connection port 17.

[0014] Three locking recesses 19, 19... are formed on the outer peripheral surface of the mounting portion 15. The locking recesses 19 are arranged at equal intervals in the circumferential direction of the mounting portion 15 and extend along the outer peripheral surface of the mounting portion 15. At the front end of the mounting portion 15, a notch 20 is formed in approximately half of the left-rotation side of each locking recess 19 when viewed from the front. Therefore, this half of each locking recess 19 is open to the front end of the mounting portion 15 via the notch 20. In each of the two locking recesses 19, 19, an inner protrusion 21 that protrudes rearward is formed on the inner surface on the front side of the locking recess 19 adjacent to the notch 20 in the circumferential direction.

[0015] The dust collection unit 3 includes a bellows portion 25 and a cap portion 26. The bellows portion 25 has each peak extending in the front-to-rear direction with a diameter slightly larger than that of the rear portion of the attachment portion 2. The cap portion 26 has a larger diameter than the bellows portion 25, and the rear end of the bellows portion 25 is connected to its front surface, opening to the rear. However, as shown in FIG. 3A , the cap portion 26 is disposed in a position where its axis A4 is eccentric from the axis A3 of the bellows portion 25 in the radial direction of the bit B. The amount of eccentricity is the same as the amount of eccentricity between the axis A1 of the attachment portion 2 and the axis A2 of the mounting portion 15. The cap portion 26 has an inner diameter slightly larger than the outer diameter of the mounting portion 15 of the attachment part 2, and can be fitted onto the mounting portion 15 from the front. Three sets of ridges 27, 27... are provided on the inner peripheral surface of the cap portion 26, protruding toward the center. Each ridge 27 extends in the circumferential direction of the cap portion 26. Each ridge 27 is formed to be shorter in the circumferential direction than the notch 20 of the mounting portion 15. The two sets of ridges 27, 27 are formed from outer protrusions 28, 28 that are separated in the circumferential direction. An inner protrusion 21 provided in the locking recess 19 of the mounting portion 15 can be locked between the outer protrusions 28, 28.

[0016] When attaching this dust collection unit 3 to the mounting part 2, first, as shown in Fig. 6, the two sets of ridges 27, 27 consisting of outer protrusions 28, 28 are aligned in phase with the notches 20, 20 of the two locking recesses 19, 19 having inner protrusions 21. Next, as shown in Fig. 7, the cap part 26 is placed over the mounting part 15 while inserting each ridge 27 into the locking recesses 19 via each notch 20. From this point, the cap portion 26 is rotated right as viewed from the front (or the mounting portion 2 is rotated left as viewed from the front). Then, as shown in Figure 8, each ridge 27 climbs onto the inner surface of the front side of each locking recess 19 and moves relatively inside the locking recess 19 in the right-rotation direction as viewed from the front. Then, each ridge 27 is locked onto the inner surface of the front side of each locking recess 19. This bayonet coupling allows the dust collection unit 3 to be coupled to the mounting portion 2 in a state where it is prevented from slipping out forward. The outer protrusions 28, 28 of the two sets of ridges 27, 27 are respectively locked onto the inner protrusions 21 in the two sets of locking recesses 19, 19, so that the cap portion 26 is also prevented from rotating when coupled.

[0017] When the cap portion 26 is bayonet-coupled to the mounting portion 15 in this manner, the bellows portion 25, which is eccentric with respect to the cap portion 26, moves in an arc around the axis A4 of the cap portion 26. Therefore, as shown in FIG. 3 , the axis A3 of the bellows portion 25 reaches a position where the axis A3 is coaxial with the axis A1 of the mounting portion 2 (the axis of the bit B). At this time, the rear end opening of the bellows portion 25 abuts against the front receiving portions 12, restricting its rearward movement. With the bellows portion 25 abutting against the front receiving portions 12, the cap portion 26 is coupled to the mounting portion 15 with the protrusions 27 riding on the front inner surfaces of the locking recesses 19. This pulls the mounting portion 2 forward, pressing the front receiving portions 12 against the cap portion 26. Therefore, the mounting portion 2 and the dust collecting portion 3 are pulled and biased toward each other's coupling sides. In the bayonet-connected state, a gap is formed in the front-to-rear direction by the front receiving portion 12 between the rear end opening of the bellows portion 25 and the front surface of the disk portion 9 of the sealing plate 8. This gap communicates with the inner spaces of the attachment portion 15 and the closing portion 16 through the space between the front receiving portions 12, 12, and further communicates with the tubular portion 18 through the connection port 17.

[0018] 1 and 2, the hammer drill 40 has a front housing 41 and a rear housing 42. The rear housing 42 has a handle 43 to which a power cord (not shown) is connected. The rear housing 42 houses a motor 44 with an output shaft 45 facing forward. The front housing 41 houses a rotating / impacting unit 46 and is attached to the front side of the rear housing 42. A front tubular portion 47 protrudes forward from the front end of the front housing 41. An inner housing 48 that supports the output shaft 45 is provided within the front housing 41. An intermediate shaft 49 parallel to the output shaft 45 is rotatably supported below the output shaft 45 between the front inner surface of the front housing 41 and the rear front surface of the inner housing 48. A cylindrical tool holder 50 extending in the front-rear direction is also housed within the front housing 41. The tool holder 50 is rotatably supported between the front tubular portion 47 and a receiving tube 51 provided at the front of the inner housing 48. A first gear 52 is provided at the rear end of the intermediate shaft 49 so as to be rotatable integrally therewith. The first gear 52 meshes with a pinion 53 formed at the tip of the output shaft 45. A second gear 54 is rotatably provided at the front end of the intermediate shaft 49, in front of the first gear 52. The second gear 54 meshes with a third gear 55 provided on the tool holder 50.

[0019] A boss sleeve 56 is rotatably mounted on the intermediate shaft 49 in front of the first gear 52. An arm 58 is mounted on the boss sleeve 56 via a swash bearing 57 with an inclined axis. A front clutch 59 and a rear clutch 60 are mounted in front of the boss sleeve 56 and between it and the second gear 54. Both clutches 59, 60 are spline-connected to the intermediate shaft 49 and are axially slidable. The front clutch 59 engages with the second gear 54 in the forward position and is separated from the second gear 54 in the reverse position. The rear clutch 60 engages with the boss sleeve 56 in the reverse position and is separated from the boss sleeve 56 in the forward position. The front and rear clutches 59, 60 are engaged with switching plates 61, 61 that are movable forward and backward within the front housing 41. The sliding positions of the front and rear clutches 59, 60 can be selected externally by sliding each switching plate 61 using a switching lever 62 mounted on the underside of the front housing 41.

[0020] A piston cylinder 65 is housed in the tool holder 50 so that it can reciprocate. The rear end of the piston cylinder 65 is connected to the arm 58. A striker 67 is housed in the piston cylinder 65 so that it can reciprocate via an air chamber 66. An impact bolt 68 is provided in front of the striker 67 inside the tool holder 50. A chuck portion 69 is provided at the tip of the tool holder 50 that protrudes from the front cylindrical portion 47, and which engages an inserted bit B (a drill bit is shown in FIG. 1). The chuck portion 69 is provided with an operating sleeve 70 for attaching and detaching the bit B.

[0021] The hammer drill 40 drives the motor 44 by pressing a trigger 71 on the handle 43. This transmits rotation of the output shaft 45 to the first gear 52, rotating the intermediate shaft 49. At this time, when the front clutch 59 is in the forward position where it engages with the second gear 54 and the rear clutch 60 is in the forward position where it is separated from the boss sleeve 56, the drill mode is activated. In the drill mode, only the second gear 54 rotates, rotating the tool holder 50 via the third gear 55. When the front clutch 59 is in the forward position and the rear clutch 60 is in the backward position where it engages with the boss sleeve 56, the hammer drill mode is activated. In the hammer drill mode, the boss sleeve 56 rotates along with the second gear 54, swinging the arm 58 back and forth via the swash bearing 57. This causes the piston cylinder 65 to reciprocate, driving the striker 67 and striking the bit B via the impact bolt 68. When the front clutch 59 is in the retracted position and the rear clutch 60 is in the retracted position, the hammer mode is activated. In the hammer mode, only the boss sleeve 56 rotates, the arm 58 swings back and forth, and the piston cylinder 65 reciprocates, striking the bit B.

[0022] As shown in FIGS. 4 and 5 , a large-diameter portion 75 is formed on the front outer surface of the front tubular portion 47 of the front housing 41. The rear end of the attachment portion 2 of the dust collection cup 1 is fitted to the large-diameter portion 75. Eight cutouts 76, 76·· are formed at equal intervals in the circumferential direction in the large-diameter portion 75. The circumferential length of each cutout 76 is long enough to allow a pair of protrusions 4, 4 provided on the inner circumference of the rear end of the attachment portion 2 to pass through in the front-rear direction. Eight engagement recesses 77, 77·· are formed on the outer circumferential surface of the front tubular portion 47 behind the large-diameter portion 75, which communicate with the rear ends of the cutouts 76 and extend clockwise beyond the cutouts 76 in a front view. After passing through each cutout 76, the pair of protrusions 4, 4 enters each engagement recess 77 and is movable in the circumferential direction.

[0023] Therefore, when using the dust cup 1, as shown in Fig. 9, the attachment portion 2 is placed over the front tubular portion 47 from the front in a phase where any pair of protrusions 4, 4 is aligned with any of the cutouts 76. Then, as shown in Fig. 10, the protrusions 4, 4 pass through the cutouts 76 and enter the engagement recesses 77. If the attachment portion 2 is then rotated clockwise in this state as viewed from the front, the protrusions 4, 4 move rearward of the large diameter portion 75 and are prevented from slipping out forward, as shown in Fig. 3. In this way, the attachment portion 2 is bayonet-coupled to the front tubular portion 47. In this state, the bit B is inserted into the dust collection cup 1 from its rear end, passed through the through-hole 11 of the seal plate 8, and attached to the chuck portion 69. The operating sleeve 70 can be operated through the windows 6, 6 formed in the attachment portion 2. The attached bit B is coaxially surrounded by the bellows portion 25 of the dust collection portion 3. The space around the bit B within this bellows portion 25 is in communication with the front space of the seal plate 8, which is surrounded by the front receiving portion 12. As described above, this front space is in communication with the attachment portion 15, the inside of the blocking portion 16, and the connection port 17 from between the front receiving portions 12, 12.

[0024] When drilling a hole in a workpiece using the dust collection cup 1 and hammer drill 40 configured as described above, the dust collection portion 3 of the dust collection cup 1 is pressed against the workpiece to contract the bellows portion 25, and the tip of the bit B is positioned at the drilling position. When the hammer drill 40 is operated in drill mode or hammer drill mode in this state, the bit B rotates and drills a hole in the workpiece. The bellows portion 25 contracts as the bit B drills a hole, allowing the hammer drill 40 and the mounting portion 2 to move forward. At this time, the rear end of the bellows portion 25 abuts against the four front bearing portions 12 of the mounting portion 2, so the repulsive force associated with compression is evenly borne by the four front bearing portions 12. Therefore, the bellows portion 25 is less likely to tilt relative to the bit B and is compressed linearly along the axis A3.

[0025] Dust generated from the workpiece during drilling is collected inside bellows section 25. If an external dust collector is not used, plugging 29 into tubular section 18 will prevent the dust collected inside bellows section 25 from leaking out. After work is completed, plug 29 can be removed and the dust can be discharged from tubular section 18 or the front end of bellows section 25. On the other hand, when an external dust collector is used, as shown in Figure 11, a cylindrical adapter 30 is connected to the cylindrical portion 18 instead of the plug, and a flexible hose 31 of the external dust collector is connected to this adapter 30. Therefore, when the dust collector is operated, the generated dust passes through the attachment portion 15 of the mounting portion 2, the closing portion 16, the connection port 17, and the cylindrical portion 18, and is sucked into the dust collector via the adapter 30 and flexible hose 31. This allows dust to be effectively discharged in parallel with the drilling work. At this time, a gap (air passage) is formed by the front receiving portion 12 between the front surface of the sealing plate 8 and the rear end opening of the bellows portion 25, so that the air sucked in from inside the dust collecting portion 3 flows smoothly through the outside of the front receiving portions 12, 12 and between the front receiving portions 12, 12 toward the connection port 17, as shown by the dotted line in Figure 11B.

[0026] In this way, in the dust collection cup 1 and hammer drill 40 of the above embodiment, the connection port 17 of the flexible hose 31 (an example of a dust collection hose) is provided radially outside and rearward of the bit B from the sealing plate 8 (an example of a sealing portion) on the outer surface of the mounting portion 2. The connection port 17 is positioned so that the radial distance D1 from the axis A1 of the mounting portion 2 to point P1 (an example of the outermost position) is longer than the radial distance D2 from the axis A1 to point P2 on the outer surface of the mounting portion 2 located on the opposite side of the axis A1. According to this configuration, only the connection port 17 can be disposed at a position away from the axis A1 of the mounting part 2, and the bellows part 25 of the dust collecting part 3 can be formed to fit the mounting part 2 excluding the part where the connection port 17 is formed. Therefore, even with the connection port 17, the dust collecting part 3 can be made compact, and good visibility can be ensured.

[0027] The dust collection unit 3 is detachable from the attachment unit 2. Therefore, if the dust collection unit 3 is damaged, it can be easily replaced. Furthermore, if multiple dust collection units 3 with different shapes are prepared according to the work, the dust collection unit 3 can be easily selected and used. The mounting part 2 and the dust collecting part 3 have circular cross sections, and the attachment part 15 and the closing part 16 (an example of the part forming the connection port 17) of the mounting part 2 are provided eccentrically from the axis A1 toward the connection port 17. Therefore, the connection port 17 alone can be easily positioned away from the axis A1 of the mounting part 2. The attachment part 2 and the dust collecting part 3 are bayonet-connected and are biased in the connecting direction in this connected state, so that the dust collecting part 3 can be easily attached and detached and a stable connected state can be maintained.

[0028] Mounting part 2 is provided with front support part 12 (an example of a support part) that abuts around the rear end opening of bellows part 25 of dust collecting part 3 and supports bellows part 25 evenly in the circumferential direction. Therefore, the pressing load applied to bellows part 25 during use can be received in the direction of axis A3, making it difficult for bellows part 25 to tilt. Front support part 12 also ensures an air passage. The front receiving portion 12 also serves to position the seal plate 8. This results in a rational configuration that allows for a reduction in the number of parts. The mounting portion 2 can be attached to and detached from the hammer drill 40 by bayonet connection, so that the dust collecting cup 1 can be easily selected for use as needed. The mounting portion 2 can be mounted to the hammer drill 40 at a number of selectable positions around the axis of the bit B. Therefore, the orientation of the connection port 17 can be selected to suit the work.

[0029] Modifications of the present disclosure will be described below. The number and shape of the ribs and locking recesses in the bayonet connection between the dust cup mounting portion and the dust collecting portion are not limited to those in the above embodiment. The ribs and locking recesses may be reversed, with the ribs on the mounting portion and the locking recesses on the dust collecting portion. The mounting portion may be attached to the cap portion. In this case, the ribs or locking recesses are provided on the inner circumferential surface of the mounting portion, and the locking recesses or ribs are provided on the outer circumferential surface of the cap portion. Instead of the ridges, protrusions that do not extend in the circumferential direction may be provided, and instead of the locking recesses, L-shaped slits may be provided. The cross sections of the attachment part and the dust collection part are not limited to being circular. For example, the attachment part and the cap part may have an elliptical cross section with the connection port located at an eccentric position. The attachment part and the cap part may also have a polygonal shape other than an ellipse. The attachment part and the dust collecting part may be connected by a structure other than a bayonet connection. For example, one of the attachment part and the dust collecting part may have a locking part such as a claw on one side and a locking part such as a recess or hole on the other side, and they may be connected by locking in the axial direction. The attachment part and the dust collecting part may also be simply fitted (press-fit) by their openings. The connection port of the mounting part does not have to open obliquely backward as in the above embodiment. The connection port may open in a direction whose axis is the radial direction of the mounting part. The cylindrical part may be omitted.

[0030] In the bayonet connection between the mounting portion and the front cylindrical portion of the power tool, the number and shape of the protrusions and engaging recesses are not limited to those in the above embodiment. The protrusions and engaging recesses may be reversed, with the protrusions provided on the front cylindrical portion and the engaging recesses provided on the mounting portion. Instead of the protrusions, circumferentially extending ridges may be provided, and instead of the engagement recesses, L-shaped slits may be provided. The mounting portion and the front tubular portion may be connected by a structure other than a bayonet connection. For example, a locking portion such as a pawl may be provided on one of the mounting portion and the front tubular portion, and a locked portion such as a recess or hole may be provided on the other, allowing them to be engaged and disengaged in the axial direction. The mounting portion may also be simply fitted onto the front tubular portion.

[0031] The dust collecting part may not be detachable from the mounting part, but may be provided integrally therewith. The dust collection section is not limited to a structure including a bellows portion as in the above-described embodiment. For example, Figures 12 and 13 show an example in which a chipping bit B1 is attached to a hammer drill 40. In this example, the dust collection section 3A of the dust collection cup 1 is provided with a cylindrical portion 35 that is not a bellows portion. The rear end opening of the cylindrical portion 35 is received by the front receiving portion 12. The front portion of the cylindrical portion 35 forms an expanding portion 36 that expands in a tapered shape toward the front. The other configurations are the same as those in the above-described embodiment. In this way, if different types of dust collecting units 3A are prepared, the dust collecting unit 3 can be replaced depending on the work being done.

[0032] The power tool is not limited to the hammer drill of the above embodiment, but may be one that employs a crank mechanism in the rotating / impacting section, or an electric drill without an impact section. In other words, the present disclosure can be applied to other power tools as long as the dust collection cup of the present disclosure can be attached to the front cylindrical section at the front end of the housing. [Explanation of symbols]

[0033] 1 dust collection cup, 2 mounting portion, 3, 3A dust collection portion, 4 projection, 7 front end portion, 8 seal plate, 9 disc portion, 10 tapered portion, 11 through hole, 12 front receiving portion, 13 rear receiving portion, 15 mounting portion, 16 blocking portion, 17 connection port, 18 tubular portion, 19 locking recess, 20 notch portion, 21 inner projection, 25 bellows portion, 26 cap portion, 27 ridge, 28 outer projection, 30 adapter, 31 flexible hose, 35 tubular Shape portion, 40··Hammer drill, 41··Front housing, 42··Rear housing, 44··Motor, 45··Output shaft, 46··Rotating / impact portion, 47··Front tubular portion, 48··Inner housing, 49··Intermediate shaft, 50··Tool holder, 65··Piston cylinder, 67··Striker, 68··Impact bolt, 75··Large diameter portion, 76··Cutout portion, 77··Engagement recess, A1··Axis of mounting portion, A2··Axis of attachment portion, A3··Axis of bellows portion, A4··Axis of cup portion.

Claims

1. A dust collection cup is attachable to a power tool, and has a cylindrical attachment portion through which a bit attached to the power tool in the attached state passes, and a cylindrical dust collection portion provided in front of the attachment portion and through which the bit passes, a seal portion having a through hole for the bit is provided between the attachment portion and the dust collection portion, and a connection port for a dust collection hose is provided on the outer peripheral surface of the attachment portion radially outward of and rearward of the seal portion, The mounting part and the dust collecting part have circular cross sections, and the portion of the mounting part where the connection port is formed is provided eccentrically from the axis of the mounting part toward the connection port, and the connection port is disposed at a position where the distance from the axis to its outermost position in the radial direction is longer than the distance from the axis to the outer peripheral surface of the mounting part located on the opposite side of the axis in the radial direction; A dust collection cup characterized in that the rear end of the dust collection section has a large diameter section that is larger in diameter than the front part of the dust collection section and is connected to the front end of the mounting section, including the part that forms the connection port, and the connection port is connected to the mounting section and the dust collection section.

2. The dust collection cup according to claim 1 , wherein the dust collection part is detachable from the attachment part.

3. 3. The dust collecting cup according to claim 1, wherein the mounting portion and the dust collecting portion are bayonet-coupled.

4. 4. The dust collecting cup according to claim 1, wherein the attachment portion is provided with a receiving portion that abuts against the periphery of the opening at the rear end of the dust collecting portion and supports the dust collecting portion evenly in the circumferential direction.

5. 5. The dust collecting cup according to claim 4, wherein the receiving portion also serves to position the sealing portion.

6. 6. The dust collecting cup according to claim 1, wherein the attachment portion is detachably attached to the power tool by a bayonet connection.

7. The dust collection cup according to claim 6, wherein the attachment portion can be attached to the power tool at a plurality of selectable positions around the axis of the bit.

8. 8. A power tool comprising a dust collecting cup according to claim 1 attached to a front end portion of the power tool to which a bit is attached.

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