Long pole type grinding machine

Abstract

To provide a long rod type polishing machine which inhibits leakage and falling of powder dust.SOLUTION: A dry wall sander, one example of a long rod type polishing machine, includes: a head part 8 having an electric motor 78 and a pad 82 which is moved by driving force of the electric motor 78; and a rod part 2 in which the head part 8 is connected to its end and which extends in an anteroposterior direction. The head part 8 has: a vertical wall part G which encloses the radial outer side of the pad 82; and a ground member 86 which is disposed between the vertical wall part G and the pad 82 and encloses the radial outer side of the pad 82. The ground member 86 has: a brush attachment part 180; and a brush 184 disposed at the lower side of the brush attachment part 180. A lower end of the brush 184 is located below a lower end of the vertical wall part G. The brush attachment part 180 has through holes extending in a radial direction of the pad 82.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to long rod grinders such as drywall sanders, long rod polishers, long rod grinders, long rod concrete cannons, etc.

Background Art

[0002] A tool holder head of a hand-held grinder as shown in the specification of European Patent No. 2202029 (Patent Document 1) is known. This tool holder head 10 includes a disc device 12, a housing 14, and a brush device 58 whose joint surface 60 is joined to the processing surface. The brush device 58 forms a brush-shaped ring or a lip-shaped ring. The brush device 58 is elastically supported by the disc device 12 via a spring element 68 that forms a number of spring tongues 70. The brush device 58 surrounds the tool accommodation device 22 and the tool coupled thereto, and when joined to the processing surface, seals the processing surface and the tool from the side, contributing to optimal dust suction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In such a tool holder head 10, particularly when polishing a wall surface, dust that cannot be sucked in may accumulate inside the lower part of the brush device 58 and inside the lower part of the side portion 18 of the housing 14. In this case, the accumulated dust may leak to the outside during polishing or fall when the brush device 56 is separated from the wall surface. The leaked and fallen dust will stain the surroundings and require cleaning to remove.

[0005] Therefore, the main object of the present disclosure is to provide a long pole type grinder in which dust leakage and dropping are suppressed.

Means for Solving the Problems

[0006] To achieve the above object, it includes an electric motor, a head portion having a pad that moves by the driving force of the electric motor, and a pole portion having the head portion connected to an end portion and extending in the front-rear direction. The head portion The above-mentioned a grounding member surrounding the radially outer side of the pad, a head cover disposed above the grounding member; and has the head cover has a vertical wall portion surrounding the outer side in the radial direction of the pad; The grounding member it is disposed between the vertical wall portion and the pad with a gap between the vertical wall portion; has a brush mounting portion and a brush disposed below the brush mounting portion. The lower end of the brush is located below the lower end of the vertical wall portion. The brush mounting portion has a through hole extending in the radial direction of the pad, a brush mounting portion main body base portion extending in the radial direction of the pad, a brush mounting portion main body wall portion having a smaller diameter than the brush mounting portion main body base portion, and a connecting portion connecting the brush mounting portion main body base portion and the upper portion of the brush mounting portion main body wall portion. The brush and the brush mounting portion main body wall portion face the same direction. The through hole is disposed between the brush mounting portion main body base portion and the brush mounting portion main body wall portion and is disposed radially inward of the brush. There is provided a long pole type grinder.

Effects of the Invention

[0007] The main effect of the present disclosure is to provide a long pole type grinder in which dust leakage and dropping are suppressed.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present disclosure and modification examples thereof will be described based on the drawings as appropriate. This embodiment relates to a drywall sander 1 as an example of a long pole type polishing machine. The front-back, up-down, left-right in this embodiment and modification examples are defined for convenience of explanation, and may change depending on at least one of the working situation and the state of the moving members. Note that the present disclosure is not limited to this embodiment and modification examples.

[0010] [First Embodiment] FIG. 1 is a perspective view of a drywall sander 1 according to the first embodiment of the present disclosure. The drywall sander 1 includes a pole part 2, a handle part 4, a suspension frame part 6, and a head part 8.

[0011] The rod part 2 extends in the front-rear direction. The rod part 2 has a large-diameter pipe 10 as the first rod body and a small-diameter pipe 12 as the second rod body. By one of the large-diameter pipe 10 and the small-diameter pipe 12 sliding relative to the other, the rod part 2 has a telescopic mechanism and can be telescopically extended and retracted. The large-diameter pipe 10 is a two-hole pipe having a first hollow part and a second hollow part. The large-diameter pipe 10 is formed by extrusion of an aluminum material. The first hollow part is cylindrical. The small-diameter pipe 12 passes through the first hollow part. The second hollow part has a cross-sectional "U" shape following the lower part of the small-diameter pipe 12. On the outer surface of the large-diameter pipe 10 (the adjacent part of the partition wall separating the first hollow part and the second hollow part), a pair of left and right large-diameter pipe guide grooves 13 are provided and each extends in the front-rear direction. The large-diameter pipe guide grooves 13 guide the sliding of the large-diameter pipe 10 in the front-rear direction and also position the large-diameter pipe 10 in the up-down, left-right directions. The small-diameter pipe 12 can slide into the inside of the large-diameter pipe 10. The small-diameter pipe 12 is cylindrical. The small-diameter pipe 12 is attached to a front handle housing 14 and a rear handle housing 15 which are the outer contours of the handle part 4. The front handle housing 14 and the rear handle housing 15 constitute a handle housing 16.

[0012] FIG. 2 is a perspective view of the rear part of the drywall sander 1. The rear handle housing 15 is split into left and right halves. The rear handle housing 15 includes a left part of the rear handle housing and a right part of the rear handle housing. The left part of the rear handle housing and the right part of the rear handle housing are fixed by screws in the left-right direction (not shown) in a combined state with each other. The front handle housing 14 is split into left and right halves. The front handle housing 14 includes a left part of the front handle housing and a right part of the front handle housing. The left part of the front handle housing and the right part of the front handle housing are fastened together by a screw 19 in the left-right direction in a combined state. The rear end portion of the front handle housing 14 is expanded in a bowl shape with respect to its cylindrical front portion, and sandwiches the front end portion of the rear handle housing 15. The front handle housing 14 is attached to the rear handle housing 15. The front handle housing 14 has a front rod storage portion 20. The front rod storage portion 20 extends back and forth and stores the rod portion 2. The rear handle housing 15 has a rear rod storage portion 21, a grip base portion 22, a grip portion 24, a battery mounting portion 26, and a joint holding portion 28. The rear rod storage portion 21 extends back and forth and stores the rod portion 2. The grip base portion 22 is hill-shaped and is disposed above the rear rod storage portion 21. The grip portion 24 is in a "T" shape when viewed from above and protrudes rearward from the upper rear portion of the grip base portion 22. The battery mounting portion 26 is disposed behind the rear rod storage portion 21. The joint holding portion 28 protrudes downward from the lower center of the rear rod storage portion 21 and spreads rearward. The joint holding portion 28 is disposed under the front of the battery mounting portion 26. A joint 30 (dust collector connection portion) is held by the joint holding portion 28. The joint 30 is made of plastic and is cylindrical including a space in an "S" shape when viewed from the side. The joint 30 extends from between the rear rod storage portion 21 and the battery mounting portion 26 to the joint holding portion 28. The rear end portion of the small-diameter pipe 12 is connected to the upper end portion of the joint 30 that is open at the front. A dust collection hose of a dust collector (not shown) is connected to the lower end portion of the joint 30 that is open at the rear (dust collection hose connection portion, dust collector connection portion).

[0013] The front rod storage portion 20 is formed in a cylindrical shape. The front rod storage portion 20 protrudes forward from the front end portion of the rear handle housing 15. On the outside of the front end of the front rod storage part 20, a pipe fixing mechanism 32 is arranged. The pipe fixing mechanism 32 includes an outer cylinder 34. The outer cylinder 34 is movable back and forth by rotating around the front-rear direction with respect to the front end of the front rod storage part 20. When the outer cylinder 34 is rotated in the advancing direction by the user, the pipe fixing mechanism 32 loosens the contact pressure on the large-diameter pipe 10. Therefore, the large-diameter pipe 10 can move back and forth relative to the small-diameter pipe 12, and the length of the rod part 2 can be changed. The user rotates the outer cylinder 34 in the retreating direction when the desired length is obtained in the rod part 2. Then, the pipe fixing mechanism 32 fixes the large-diameter pipe 10 by pressing contact. In this way, the rod part 2 can be fixed at an arbitrary telescopic position by the pipe fixing mechanism 32.

[0014] The handle part 4 is provided at the rear part (the second end part) of the rod part 2. The handle part 4 includes the above-mentioned front handle housing 14 and rear handle housing 15, joint 30 and pipe fixing mechanism 32, trigger 40, lock-on member 42, trigger lock member 44, speed adjustment dial 46, and wireless communication adapter insertion part 48.

[0015] A battery 50 as a power supply can be mounted on the battery mounting part 26 of the rear handle housing 15. The battery 50 is in the shape of a rectangular parallelepiped (quadrangular prism) and can be charged by a charger (not shown). The battery 50 is a rechargeable battery for power tools. The battery 50 is mounted on the battery mounting part 26 by being slid rightward from the left side of the battery mounting part 26 with its longest side facing the left-right direction. Also, the mounted battery 50 is removed by being slid leftward in a state where a battery button (not shown) is slid rearward to release the locking to the battery mounting part 26. The battery 50 is an 18V output lithium-ion battery, which is a general-purpose one that can also be used in other long pole type grinders and the like. Incidentally, at least any one of the shape, voltage, type, number of terminals, and mounting (removal) direction of the battery 50 may be changed from the above.

[0016] The trigger 40 extends in the front-rear direction and is disposed below a switch (not shown). The rear portion of the trigger 40 is exposed. The central portion of the trigger 40 in the front-rear direction is swingably supported with respect to the rear handle housing 15. When the trigger 40 is pulled upward, the switch is turned on.

[0017] The lock-on member 42 is disposed above the trigger 40. The lock-on member 42 extends in the left-right direction. Both the left and right end portions of the lock-on member 42 are exposed as lock-on buttons 52. When the user presses (turns on) either the left or right lock-on button 52 while pulling the trigger 40, the moved lock-on member 42 catches on the central portion of the trigger 40, preventing the trigger 40, which tries to return downward when the pull is stopped, from moving and maintaining the pulled state. Therefore, when the lock-on button 52 is turned on, the switch adjacent to the trigger 40 is maintained in the on state. When the user pulls the trigger 40 further upward, the lock-on member 42 returns to its original position, and the maintenance of the pulled state of the trigger 40 is released. Therefore, the maintenance of the on state of the switch is released.

[0018] The trigger lock member 44 is disposed in front of the trigger 40. The trigger lock member 44 extends in the left-right direction. Both the left and right end portions of the trigger lock member 44 are exposed as trigger lock buttons 54. When the user presses (turns on) the left trigger lock button 54 without pulling the trigger 40, the trigger lock member 44 is engaged with the front end of the trigger 40, preventing the trigger 40 from rising at the rear (lowering at the front) when pulled. Thus, the pulling operation of the trigger 40 is restricted. On the other hand, when the user presses (turns off) the right trigger lock button 54, the trigger lock button 54 that has returned to the left releases the restriction on the pulling operation of the trigger 40.

[0019] The speed adjustment dial 46 is held on the upper part of the grip base 22. The speed adjustment dial 46 has a disc-shaped dial portion 56. The upper part of the curved surface in the dial portion 56 is exposed upward. The user can change the switching state of the speed adjustment dial 46 by rotating the dial portion 56. The switching state of the speed adjustment dial 46 corresponds to the speed setting.

[0020] A plurality of slit-shaped ventilation holes 58 (vent openings) are formed on the left and right of the rear handle housing 15. Each ventilation hole 58 extends in a rearwardly upward direction along the upper surface of the grip base 22. Each ventilation hole 58 is arranged vertically and horizontally at the positions of the left and right parts of the rear handle housing 15 that are opposed and spaced apart. A controller (control circuit board, not shown) is arranged inside each ventilation hole 58. The controller is held at the front part of the grip base 22. The controller is electrically connected to the battery mounting portion 26, the switch adjacent to the trigger 40, and the speed adjustment dial 46 by lead wires (not shown). In addition, the controller is equipped with a display portion 60. The upper part of the display portion 60 includes four LEDs and is exposed from the upper surface of the rear handle housing 15. The controller displays the magnitude of the motor load on the display portion 60. Furthermore, a pole lead wire (not shown) extending to the head portion 8 is connected to the controller. The pole lead wire is a bundle of a plurality of single lead wires, and a part of the single lead wire (control lead wire) is connected to the controller. Another part of the single lead wire (power supply lead wire) is connected to the battery mounting portion 26 (terminal). That is, the pole lead wire is connected to the handle portion 4. The pole lead wire is disposed within the large-diameter pipe 10 (lead wire accommodation space).

[0021] The wireless communication adapter insertion portion 48 is formed in the grip base portion 22 for inserting the wireless communication adapter 62. The wireless communication adapter insertion portion 48 is formed to be recessed box-shaped inward from the outer surface of the right portion of the rear handle housing 15, and the wireless communication adapter 62 can be inserted. When inserted, the wireless communication adapter 62 is electrically connected to a wireless communication controller (not shown) mounted on the controller. The wireless communication adapter 62 performs wireless communication with the above-described dust collector as other accessory equipment. By the wireless communication, the start operation and stop operation of the dust collector are interlocked with the start operation and stop operation of the drywall sander 1. In advance, an association (pairing) for enabling wireless communication is performed between the wireless communication adapter 62 and a dust collector side wireless communication adapter attached to the dust collector. The pairing is performed when the user presses a button of the dust collector side wireless communication adapter and operates a button (not shown) of the wireless communication adapter 62 within a predetermined time. When the switch adjacent to the trigger 40 is turned on and the drywall sander 1 is started in a state where the pairing is completed, start information indicating the start is transmitted from the wireless communication adapter 62 to the dust collector, and the dust collector is automatically started based on the reception of the start information by the dust collector side wireless communication adapter. The wireless communication state is notified to the user by the lighting state of an adapter lamp provided on the wireless communication adapter 62.

[0022] Figure 3 is a right side view of the front part of the drywall sander 1. Figure 4 is a central longitudinal sectional view of the front part of the drywall sander 1. Figure 5 is a sectional view taken along line A-A in Figure 4. The suspension frame part 6 includes an outer frame 64 and an inner frame 66. The outer frame 64 is bifurcated left and right and is attached to the tip of the large-diameter pipe 10. The inner frame 66 is rotatably connected around the axis in the left-right direction via left and right screws 67 inside the tip of the outer frame 64. The inner frame 66 is rectangular in top view and "V"-shaped in both front view and rear view. The head part 8 is arranged so as to be sandwiched between the lowermost parts of the "V"-shaped part at the front of the inner frame 66 and the "V"-shaped part at the rear of the inner frame 66. The head part 8 is rotatably connected to the inner frame 66 around the axis in the front-rear direction. The head part 8 can change its posture around a total of two axes in the left-right direction and the front-rear direction by the suspension frame part 6. The head part 8 mainly changes its posture around the axis in the left-right direction by the relatively large outer frame 64. Also, the head part 8 is supplemented to change its posture around the axis in the front-rear direction by the relatively small inner frame 66.

[0023] The head part 8 is connected via the suspension frame part 6 at the front end part (the first end part) of the rod part 2. The head part 8 includes an outer head housing 70, a motor housing 72, a gear housing 74, an electric motor 78 as a drive source, a planetary gear mechanism 80, a spindle 81, a pad 82, a head part cover 83, a stopper 84, an air guide member 85, a grounding member 86, and a conductive plate 87. The outer head housing 70, the motor housing 72, and the gear housing 74 constitute a head housing 88. Figure 6 is an exploded perspective view of the gear housing 74, the head part cover 83, the stopper 84, the air guide member 85, and the conductive plate 87.

[0024] The outer housing 70 of the head portion is made of plastic and has a bottomed cylindrical shape. The lower part of the outer housing 70 of the head portion is open. Boss portions 89 are formed on the front and rear of the outer housing 70 of the head portion. A suspension frame portion 6 (inner frame 66) is rotatably connected to each boss portion 89 via bolts 90 in the front-rear direction. A first hose connection portion 92 is formed at the upper front part of the outer housing 70 of the head portion. The first hose connection portion 92 protrudes cylindrically upward from other parts. The front end portion of a first hose 94 is connected to the first hose connection portion 92. The first hose 94 is connected to the upper rear part of the suspension frame portion 6 in a state of communicating with the large-diameter pipe 10. The first hose 94 is routed so as to maintain an inverted "U" shape in side view. The first hose 94 is made of conductive plastic. A conductive material is compounded in the first hose 94. The conductive material is, for example, carbon. In order to obtain sufficient conductivity in the first hose 94, a conductive material of 0.5% or more by weight ratio may be compounded. Also, in order to suppress the cost while ensuring conductivity in the first hose 94, a conductive material of 3% or less by weight ratio may be compounded. The first hose 94 exhibits conductivity due to the compounding of the conductive material, and the charging property (generation of static electricity) is suppressed. An opening is formed below the boss portion 89 in front of the outer housing 70 of the head portion.

[0025] The motor housing 72 is made of plastic and is disposed inside the outer housing 70 of the head portion. The motor housing 72 is divided into left and right halves and is combined by a plurality (six) of screws 96 in the left-right direction. The motor housing 72 has a cylindrical motor housing main body portion 98 and an extension portion 99. The extension portion 99 extends downward, rearward, and upward from the rear portion of the motor housing main body portion 98. The rear portion of the extension portion 99 extends out from the opening behind the outer housing 70 of the head portion. The front end of the second hose 102 is connected to the exposed upper end of the extension part 99. The second hose 102 is connected to the lower rear part of the suspension frame part 6 in a state of communicating with the large-diameter pipe 10. The second hose 102 is routed so as to maintain an inverted "J" shape in side view. Inside the large-diameter pipe 10, the second hose 102, and the extension part 99, the front part of the pole part lead wire that exits from the controller of the handle part 4 and passes through the pole part 2 is arranged. A pair (male and female) of connectors 104 that can be freely connected and disconnected by attachment and detachment are interposed in the part of the pole part lead wire arranged in the extension part 99. In addition, the rear end of the first hose 94 is connected to the first hollow part of the large-diameter pipe 10. Also, the rear end of the second hose 102 is connected to the second hollow part of the large-diameter pipe 10.

[0026] The upper part of the gear housing 74 is cylindrical, and the lower end part is disk-shaped. The gear housing 74 is attached below the motor housing 72 by a plurality (six) of vertical screws 105 (FIG. 6). The lower end part of the motor housing main body part 98 is fitted into the opening at the upper end of the gear housing 74. The upper surface edge of the lower part of the gear housing 74 enters the opening at the lower end of the outer housing 70 of the head part. The gear housing 74 is attached to the outer housing 70 of the head part together with the motor housing 72. The gear housing 74 is made of plastic.

[0027] The electric motor 78 is held by the motor housing 72. The electric motor 78 is a DC-driven brushless motor and is held inside the upper part of the motor housing main body part 98. The electric motor 78 includes a stator 106 and a rotor 108. The rotor 108 is arranged inside the stator 106 (inner rotor type). The stator 106 has a plurality (six) of drive coils 116. The rotor 108 has a motor shaft 120 as a rotational drive shaft. The motor shaft 120 extends vertically and is arranged coaxially with the rotation center axis of the rotor 108. A pinion 125 is integrally fixed to the lower end of the motor shaft 120. The pinion 125 has a plurality of external teeth.

[0028] The stator 106 is electrically connected to the controller via the pole lead wire. The electric motor 78 is controlled by the controller. The controller has six switching elements (not shown). Each switching element is provided corresponding to one of the drive coils 116 and performs the switching of the corresponding drive coil 116. Incidentally, the controller has a microcomputer (not shown). The microcomputer controls the switching of the switching elements. The controller is equipped with various elements for controlling the electric motor 78.

[0029] An upper bearing 132 is provided above the stator 106. The upper bearing 132 rotatably supports the motor shaft 120. The upper bearing 132 is held by the motor housing 72. A lower bearing 134 is provided above the pinion 125. The lower bearing 134 rotatably supports the motor shaft 120. The lower bearing 134 is fixed at the lower central portion of the motor housing 72. A cooling fan 136 is arranged between the lower bearing 134 of the motor shaft 120 and the stator 106. The fan 136 is fixed to the motor shaft 120 and sends out wind in the centrifugal direction by rotation (centrifugal fan). The fan 136 is arranged inside the central portion of the motor housing 72. Inner exhaust ports 137 are formed at the left and right central portions of the motor housing 72. Outer exhaust ports 138 are formed at the left and right central portions of the outer housing 70 of the head portion and outside each inner exhaust port 137. The inner exhaust ports 137 and the outer exhaust ports 138 are located radially outward of the fan 136. Therefore, the wind of the fan 136 is efficiently discharged. On the other hand, a plurality of air inlets 139 are formed in the upper part of the outer housing 70 of the head portion and the upper part of the motor housing 72. The air inlets 139 connect the outside and the inside of the motor housing 72 in a ventilatable manner.

[0030] The planetary gear mechanism 80 is held on the upper part of the gear housing 74. The planetary gear mechanism 80 has two-stage planetary gear trains made of metal. Each planetary gear train has the gear housing 74 as an outer shell and is arranged around the vertical axis (including the central axis of the motor shaft 120 and the central axis of the spindle 81). The planetary gear mechanism 80 decelerates the rotation of the motor shaft 120 and transmits it to the spindle 81. That is, the planetary gear mechanism 80 has an upper planetary gear train 140 (the first-stage reduction mechanism) and a lower planetary gear train 150 (the second-stage reduction mechanism).

[0031] The spindle 81 is made of metal and is arranged at the lower part of the gear housing 74. The rear end portion of the spindle 81 is attached to the central part of the carrier of the lower planetary gear train 150. The spindle 81 is rotatably supported by a spindle upper bearing 162 and a spindle lower bearing 164. The spindle upper bearing 162 and the spindle lower bearing 164 are held by the gear housing 74.

[0032] The pad 82 is made of plastic and is disk-shaped. The pad 82 is attached to the spindle 81 by a vertical screw 168. The upper part of the pad 82 is arranged inside the grounding member 86. The pad 82 is arranged below the motor housing 72. A tip tool T such as sandpaper is attached to the lower surface of the pad 82. The tip tool T serves as a polishing surface for polishing the work surface K (Figure 3) of the workpiece, and also serves as a working surface for applying a working action to the work surface K. Pad 82 has a plurality of vertically oriented pad holes 170. Each pad hole 170 is arranged to be aligned along a virtual circle concentric with pad 82. Each pad hole 170 is arranged at equal intervals in the circumferential direction. The tip tool T has tip tool holes similar to the pad holes 170. In addition, a vertically oriented gear housing hole (not shown) is formed in the front lower part of the gear housing 74. Above the gear housing hole, there is a space S located between the front part of the outer housing 70 of the head portion and the front part of the motor housing 72. Further, above the space S, there is a first hose connection portion 92 located. The front part of the outer housing 70 of the head portion bulges in a cylindrical shape (semicylindrical shape), and the space S has a cylindrical shape extending in the vertical direction. On the other hand, the lower end portion of the space S communicates with a space communication hole (not shown in the first embodiment) opened in the lower part of the gear housing 74.

[0033] FIG. 7 is an enlarged cross-sectional view of a part of the head cover 83, the stopper 84, the air guide member 85, and the grounding member 86, and is a view when machining the wall B. The cross-section is a vertical plane extending from the right front to the left rear, that is, a plane extending in the front-rear and up-down directions, rotated 45° counterclockwise when viewed from above around a virtual vertical axis passing through the center of the head cover 83 and the like. Note that the up-down, left-right, front-back of the drywall sander 1 is the same as in the case other than FIG. 7 regardless of the orientation shown in FIG. 7, except for the up-down, front-back, left-right in the description of the machining of the wall B in the operation example described later. The head cover 83 is made of plastic and is ring-shaped. The head cover 83 has, at its periphery, a cylindrical wall-shaped vertical wall base portion 171 that protrudes downward more than other portions. In addition, a plurality (six) of screw bosses 172 are provided on the head cover 83. Each screw boss 172 is arranged to be aligned in the circumferential direction of the head cover 83. Furthermore, the head cover 83 has a plurality of upper through holes H2. Each upper through hole H2 is arranged at the periphery of the upper surface portion of the head cover 83. The center of each upper through hole H2 is located on a virtual concentric circle. Below the head cover 83, a stopper 84 is arranged. The stopper 84 is made of plastic and is ring-shaped. The stopper 84 is fixed to the head cover 83 by a plurality (six) of screws 174 in the vertical direction. Each screw 174 fits into a corresponding screw boss 172.

[0034] An air guide member 85 is arranged at the longitudinal wall base 171 of the head cover 83. The air guide member 85 is made of an elastic body (rubber) and is ring-shaped. More specifically, the material of the air guide member 85 exhibits non-contaminating properties. That is, the air guide member 85 is made of non-contaminating rubber. The non-contaminating rubber is a rubber-based material with non-contaminating compounding agents added. Therefore, the situation where the air guide member 85 hitting the workpiece surface K etc. contaminates the workpiece surface K etc. is suppressed. The air guide member 85 is detachably fixed to the head cover 83 by fitting its upper part into the longitudinal wall base 171 of the head cover 83. That is, on the outer lower side of the longitudinal wall base 171 of the head cover 83, a protrusion 176 protruding radially outward more than other parts is formed. The protrusion 176 is ring-shaped as a whole. The shape of the longitudinal section of the protrusion 176 is an inverted "T" shape. On the other hand, on the upper part of the air guide member 85, a groove part 178 having a hole with the same shape as the protrusion 176 is formed. And by inserting the protrusion 176 into the groove part 178, the air guide member 85 is attached to the head cover 83. The inner and lower parts of the central portion of the air guide member 85 are formed as cylindrical wall-shaped and conical wall-shaped vertical wall extension parts 179. The vertical wall extension part 179 extends the vertical wall base part 171 of the head part cover 83. The vertical wall extension part 179 and the vertical wall base part 171 constitute the vertical wall part G. The upper part of the vertical wall extension part 179, i.e., the upper part 179A of the vertical wall extension part, includes the cylindrical inner surface inside the lower part of the groove part 178. The lower part of the vertical wall extension part 179, i.e., the lower part 179B of the vertical wall extension part, includes the conical inner surface below the groove part 178. The lower part 179B of the vertical wall extension part tapers downward. That is, the inner diameter of the lower part 179B of the vertical wall extension part gradually becomes smaller as it goes downward. The upper part 179A of the vertical wall extension part and the lower part 179B of the vertical wall extension part are connected by a ring-shaped horizontal plane 179C. In addition, the lower part 179B of the vertical wall extension part may taper upward or may be vertical. The same applies to the vertical wall base part 171. The directions (taper directions) of the vertical wall base part 171 and the vertical wall extension part 179 may be the same. The inner surfaces of the upper part 179A of the vertical wall extension part and the lower part 179B of the vertical wall extension part may be a series of conical wall shapes or a series of cylindrical wall shapes. Also, the head part cover 83 (vertical wall base part 171) and the air guide member 85 (vertical wall extension part 179) may be integrated. Furthermore, the air guide member 85 may have only the vertical wall extension part 179.

[0035] The head part cover 83 and the stopper 84 are mounted on the radially outer side of the lower end part (disk-shaped part) of the gear housing 74. The radially inner edge part of the head part cover 83 and the radially inner edge part of the stopper 84 sandwich the edge part of the disk-shaped part of the gear housing 74. The head part cover 83, the stopper 84, the air guide member 85, and the grounding member 86 are stationary with respect to the gear housing 74 due to the frictional force between the head part cover 83 and the stopper 84 when no external force is applied. On the other hand, when an external force is applied, the head part cover 83, the stopper 84, the air guide member 85, and the grounding member 86 can rotate 360 degrees in both directions around a virtual vertical axis around the periphery of the disk-shaped part of the gear housing 74. The head cover 83, the stopper 84, the air guide member 85, and the grounding member 86 rotate by hitting against a wall B, the ceiling, the floor, etc. At least one of the head cover 83 and the air guide member 85 can come into contact with the wall B or the like. By this contact, the impact on the head portion 8 is mitigated. Also, the rotation of the grounding member 86 or the like is made smooth.

[0036] FIG. 8 is a perspective view of the lower side of the grounding member 86 as seen obliquely from below. FIG. 9 is an exploded perspective view of the upper side of the grounding member 86 as seen obliquely from above. The grounding member 86 is disposed below the head cover 83. The grounding member 86 is generally cylindrical. The grounding member 86 has a brush mounting portion 180, a plurality (four) of leaf springs 182 as elastic bodies, and a brush 184.

[0037] The brush mounting portion 180 is made of conductive plastic. The brush mounting portion 180 is below the head cover 83 and is disposed radially inward of the longitudinal wall base portion 171 of the head cover 83. The brush mounting portion 180 has a ring-shaped brush mounting portion main body 185 and a plurality (six) of protruding pieces 186. A brush mounting portion main body base portion 185A, which is the ring-shaped upper portion of the brush mounting portion main body 185, is concentric with a brush mounting portion main body wall portion 185B, which is the ring-shaped lower portion. The diameter of the brush mounting portion main body base portion 185A is larger than the diameter of the brush mounting portion main body wall portion 185B. The brush mounting portion main body wall portion 185B extends in the vertical direction and the circumferential direction. The brush mounting portion main body 185 has a plurality of connecting portions 187 that connect the brush mounting portion main body base portion 185A and the brush mounting portion main body wall portion 185B. Each connecting portion 187 is arranged at equal intervals in the circumferential direction. Between each pair of adjacent connecting portions 187 in the circumferential direction is a through hole H1. Each through hole H1 extends in the circumferential direction. Each connecting portion 187 is the portion between a pair of adjacent through holes H1. The total circumferential length of all the through holes H1 is larger than the total circumferential length of the portions between all the through holes H1 (all the connecting portions 187). The set of through holes H1 is arranged so as to extend over the entire circumference of the brush mounting portion main body 185. Each upper through-hole H2 is disposed above the base portion 185A of the brush mounting portion main body. Each protruding piece 186 protrudes radially inward from the upper side portion of the brush mounting portion main body wall portion 185B of the brush mounting portion main body 185. Each protruding piece 186 can come into contact with the upper surface of the stopper 84. The grounding member 86 is supported so as not to fall downward by the contact of each protruding piece 186 with the upper surface of the stopper 84. Below the upper surface of each protruding piece 186, the lower surface of the head portion cover 83 is positioned with a space therebetween.

[0038] Each leaf spring 182 is made of metal and is in a "V" shape. Each leaf spring 182 is interposed between the brush mounting portion 180 and the head portion cover 83. The central portion of each leaf spring 182 is fixed to the upper end portion of the brush mounting portion 180. Both end portions of each leaf spring 182 are fixed to the head portion cover 83. Each leaf spring 182 is disposed on the front, rear, left, and right of the upper surface of the brush mounting portion 180. Incidentally, part or all of the leaf spring 182 may be fixed to either the head portion cover 83 or the brush mounting portion 180.

[0039] The brush 184 has a plurality of tufts 188. Each tuft 188 is attached to the brush mounting portion main body base portion 185A of the brush mounting portion main body 185 of the brush mounting portion 180. Each tuft 188 extends downward from the lower surface of the brush mounting portion main body base portion 185A. Each tuft 188 is planted on the brush mounting portion main body base portion 185A. The brush mounting portion main body wall portion 185B and the through-hole H1 are disposed radially inward of the brush 184. The brush mounting portion main body wall portion 185B and the brush 184 face the same direction (vertical direction). The lower end portions of each tuft 188 are aligned so as to be included in a virtual plane. Although each tuft 188 is actually an aggregate of hairs, in the drawing, for simplicity of illustration, it is shown by the virtual outer contour line of the aggregate. As shown in FIG. 7, the vertical length of the vertical wall extension portion 179 is longer than the vertical length between the lower end of the vertical wall extension portion 179 and the lower end of the brush 184 (the position of which is aligned with the lower surface of the pad 82 (tip tool T) in the vertical direction). Approximately half of each hair bundle 188 (hair bundle 188A) is arranged in contact with adjacent hair bundles 188A along a virtual circle for the first hair bundle arrangement. Also, the remaining approximately half of each hair bundle 188 (hair bundle 188B) is arranged in contact with adjacent hair bundles 188B along a virtual circle for the second hair bundle arrangement. The diameter of the virtual circle for the second hair bundle arrangement is larger than the diameter of the virtual circle for the first hair bundle arrangement. The virtual circle for the second hair bundle arrangement is concentric with the virtual circle for the first hair bundle arrangement. The vertical central axis of each hair bundle 188B along the virtual circle for the second hair bundle arrangement is along the virtual circle for the first hair bundle arrangement and is arranged between the vertical central axes of adjacent hair bundles 188A. The hair bundles 188B adjacent to both sides of each hair bundle 188A are in contact with that hair bundle 188A. In other words, with respect to an intermediate virtual circle assumed to be in the middle of the virtual circle for the first hair bundle arrangement and the virtual circle for the second hair bundle arrangement, each hair bundle 188 is arranged in a zigzag pattern in contact with adjacent hair bundles 188. Each hair in each hair bundle 188 is made of a first plastic (e.g., polyamide) and a second plastic (e.g., conductive polypropylene). That is, in each hair bundle 188, the hairs made of the first plastic and the hairs made of the second plastic are mixed. The ratio of the hairs made of the first plastic to the hairs made of the second plastic is approximately 9:1. The hairs are evenly arranged so that this ratio is maintained at any position. If the second plastic exhibits conductivity, the charging of static electricity in the hair bundle 188 is suppressed. If the hairs made of the second plastic are provided in a sufficient amount for charge suppression and the remaining hairs are made of the first plastic, the cost is reduced and the strength of the brush is more sufficiently ensured compared to the case where all the hairs are made of the second plastic. Incidentally, the hair bundles 188 having only the hairs made of the first plastic and the hair bundles 188 having only the hairs made of the second plastic may be arranged to be mixed. Also, each hair bundle 188 may contain only the hairs made of the first plastic or only the hairs made of the second plastic. The conductivity in the plastic may be ensured in the same manner as the first hose 94 described above.

[0040] The grounding member 86 surrounds the radially outer side of the pad 82. The grounding member 86 surrounds the lower surface (tip tool T) of the pad 82. The lower end of each hair bundle 188 is located below the tip tool T in the vertical direction in a state where the leaf spring 182 is at its natural length or a state closer to its natural length. The grounding member 86 can be grounded to the wall B or the like at the lower end of each hair bundle 188. Each leaf spring 182 biases the brush 184 downward, that is, toward the work surface K, via the brush mounting portion 180.

[0041] The conductive plate 87 is made of metal. The conductive plate 87 is generally in an "L" shape and has an arm portion 190 extending in the vertical direction and a base portion 191 extending substantially horizontally. The central portion of the arm portion 190 is disposed in the space S between the front portion of the outer housing 70 of the head portion and the front portion of the motor housing 72. An arcuate contact portion 192 that bulges forward and to the left with respect to other portions is formed at the upper end of the arm portion 190. The contact portion 192 is in contact with the inner surface of the first hose 94. A screw hole portion 194 is formed at the central portion of the base portion 191. A screw 105 for fixing the gear housing 74 to the motor housing 72 is inserted into the screw hole portion 194. Further, the tip portion of the base portion 191 forms an insertion portion 195. The insertion portion 195 is slightly lower than other portions via a stepped portion. Also, the width of the insertion portion 195 is larger than other portions. A hole 196 is formed in the insertion portion 195. A protrusion 198 that protrudes downward with respect to the periphery is formed on the lower surface of the disk-shaped portion of the gear housing 74. The protrusion 198 fits into the hole 196 of the insertion portion 195. The tip portion of the insertion portion 195 is inserted between the gear housing 74 and the stopper 84.

[0042] When the head portion 8 is applied to the work surface K by the user, first, the brush 184 of the grounding member 86 contacts the work surface K. When the user further presses the head portion 8 against the work surface K, then the tip tool T of the pad 82 contacts the work surface K. That is, the brush 184, which is a portion of the grounding member 86 on the work surface K side, can contact the work surface K together with the tip tool T on the lower surface of the pad 82. Also, the brush 184 contacts the work surface K before the tip tool T contacts the work surface K. At this time, the grounding member 86 receives the reaction force from the work surface K at the lower end portion of the brush 184. The brush mounting portion 180 rises with respect to the head portion cover 83 and the stopper 84 against the biasing force of the leaf spring 182. The upper end portion of the brush mounting portion 180 enters the space below the peripheral edge portion of the head portion cover 83. Each protruding piece 186 of the brush mounting portion 180 approaches the lower surface of the head portion cover 83. Here, due to the fact that the head portion 8 can move freely by the two-axis rotation in the suspension frame portion 6 and the brush 184 has already contacted the work surface K first, the pressing force on the tip tool T acts only in the direction perpendicular to the tip tool T (the axial direction of the grounding member 86, the vertical direction in the figure). The pressing force on the tip tool T in other directions becomes the rotational force of the head portion 8 with respect to the suspension frame portion 6. Therefore, the entire tip tool T contacts the work surface K. Accordingly, the situation where the rotating tip tool T hits only one side is suppressed. Even when the head portion 8 is moved by the user in various directions with respect to the work surface K, the entire tip tool T contacts the work surface K by the grounding member 86. Also, even when the rod portion 2 is changed in posture by the user at various angles with respect to the work surface K, the entire tip tool T contacts the work surface K by the grounding member 86.

[0043] On the other hand, when the head portion 8 is separated from the work surface K, the brush mounting portion 180 and the brush 184 return downward (toward the work surface K side) by the biasing force of the leaf spring 182. Therefore, the lower end portion of the brush 184 returns to a state of protruding downward in the vertical direction with respect to the tip tool T.

[0044] Such a drywall sander 1 operates, for example, as follows. That is, the user mounts the charged battery 50 on the battery mounting portion 26. Also, the user loosens the outer cylinder 34 to change the telescopic state of the rod portion 2, and then tightens the outer cylinder 34 with the rod portion 2 set to a desired length, thereby adjusting the length of the rod portion 2.

[0045] Then, the user pulls the trigger 40 with the trigger lock member 44 in the off state. Then, the switch is turned on, and the controller supplies the power of the battery 50 to the electric motor 78 via the rod lead wire (power supply lead wire), and the motor shaft 120 is rotationally driven. Thus, the trigger 40 switches the on / off of the electric motor 78 via the switch, and is a switch operation portion for operating the on / off of the electric motor 78. The trigger 40 and the switch constitute the main switch of the electric motor 78. The switching element of the controller performs the switching of each drive coil 116 according to the rotational position of the rotor 108. Thereby, the rotor 108 (motor shaft 120) rotates.

[0046] The rotational force of the motor shaft 120 is decelerated by the planetary gear mechanism 80 and transmitted to the spindle 81, and the pad 82 mounted at the tip of the spindle 81 moves (rotates). The pad 82 that moves in this way is pressed against and moved relative to the workpiece by gripping the grip portion 24 and the rod portion 2, so that processing such as polishing is performed on the processed surface K. The workpiece is, for example, a drywall (gypsum board) stretched on the wall B or ceiling of a building, and more specifically, is putty used to fill screw holes and joints during the construction of drywall. The putty protruding from other portions of the drywall is flattened by polishing.

[0047] During processing, the orientation of the head portion 8 with respect to the rod portion 2, that is, the orientation of the pad 82, is adjusted within a predetermined range by the suspension frame portion 6. Further, the grounding member 86 contacts the surface K to be processed first, and then the tip tool T contacts the surface K to be processed, thereby suppressing a situation in which the tip tool T contacts the surface K to be processed unevenly rather than parallel to it.

[0048] Also, due to the rotation of the motor shaft 120, the fan 136 rotates and air is exhausted from each inner exhaust port 137 and the outer exhaust port 138, and a flow of air (wind) from the intake port 139 to the outer exhaust port 138 is formed. This wind descends within the motor housing main body portion 98 and reaches the fan 136 in the central portion. By this wind, the internal mechanisms of the head portion 8 including the electric motor 78 are cooled. In particular, the wind descending from the upper part of the motor housing main body portion 98 passes between the stator 106 and the rotor 108 in the electric motor 78, and the electric motor 78 is efficiently cooled.

[0049] Furthermore, the controller is cooled by the air introduced by natural convection from the ventilation hole 58.

[0050] Furthermore, when the switch is turned on, the wireless communication adapter 62 is controlled by the wireless communication controller mounted on the controller, and the dust collector is started by wireless communication with the dust collector side wireless communication adapter. Dust collection by suction of air in the dust collector is performed as follows. That is, the dust generated around the pad 82 and the tip tool T that rotate appropriately during processing is mainly sucked into the dust collection hose through the following three routes. The first route is from the tip tool hole and the pad hole 170, through the gear housing hole, the space S between the outer housing 70 of the head portion and the gear housing 74, and between the outer housing 70 of the head portion and the motor housing 72, and reaches the first hose 94. Further, the first route reaches the joint 30 from the first hose 94 through the large diameter pipe 10 and the small diameter pipe 12. The dust following the first route is sucked into the dust collection hose. The second route starts between the vertical wall extension 179 and the brush 184, passes through the brush 184 (between the plurality of tufts 188), goes between the pad 82 and the head cover 83 and the cylindrical portion of the gear housing 74, reaches the gear housing hole, and merges with the first route. The third route starts from each upper through-hole H2, passes between the head cover 83 and the brush mounting portion 180, and merges with the second route. In this way, a dust collection passage including the first to third routes is formed.

[0051] An operation example of machining the vertical wall B with the pad 82 will be described below. Only in the description here, the up-down, front-back, left-right as shown in FIG. 7 is used. Note that in FIG. 7, the pad 82 is not shown. When the user machines the vertical wall B (the work surface K is vertical facing the user), the tip tool T attached to the pad 82 spreads vertically and horizontally along the vertical plane of the wall B. In this case, as shown in FIG. 7, dust D1 and D2 may accumulate. The dust D1 accumulates inside the grounding member 86. The dust D2 accumulates inside the vertical wall base portion 171 of the head cover 83. In the drywall sander 1, the dust D1 that tends to accumulate is blown away by the wind W1 generated in the second route of the dust collection passage described above. The wind W1 first passes through the gap between the wall B and the lower part 179B of the vertical wall extension. This gap is narrower than when there is no vertical wall extension 179 due to the installation of the vertical wall extension 179. Therefore, the speed of the wind W1 passing through this gap becomes faster. Next, the wind W1 passes between the vertical wall extension 179 and the brush 184 and faces the horizontal direction. Subsequently, the wind W1 is directed vertically by the brush mounting portion main body base portion 185A and passes through the brush 184 (between the plurality of tufts 188). Then, the wind W1 passes through the through-hole H1 located on the lower side, goes between the pad 82 and the head cover 83 and the cylindrical portion of the gear housing 74, reaches the gear housing hole, and is sucked. The wind W1 entering the through-hole H1 is rectified because the tufts 188 act like slits. Further, in the drywall sander 1, the dust D2 that tends to accumulate is blown away by the wind W2 that occurs in the third route of the dust collection passage described above. That is, the accumulation of the dust D2 is suppressed by the wind W2 from each upper through hole H2. In addition, a part of the wind W1 that reaches the adjacent part of the brush attachment part main body base 185A merges with the wind W2 through the space between the brush attachment part main body base 185A and the vertical wall base 171. Therefore, a part of the wind W1 blows away the dust D2. When the through hole H2 is not provided, both the dust D1 and D2 are blown away by the branched wind W1 corresponding to the wind W2.

[0052] Furthermore, in the drywall sander 1, during processing, the workpiece surface K and the dust are charged negatively and positively respectively, and static electricity is generated at each part corresponding to the passage of the charged dust. This static electricity is discharged to the workpiece surface K through the large-diameter pipe 10, the first hose 94, the conductive plate 87, the stopper 84, the brush attachment part 180, and the brush 184 to neutralize the charges generated during processing. More specifically, the static electricity generated in the internal dust collection passage passes through the arm part 190, other parts of the base part 191, and the insertion part 195 of the conductive plate 87 from the first hose 94, and reaches the brush 184 from the stopper 84 and the brush attachment part 180. In addition, discharging the charge of the dust to the workpiece surface K not only suppresses the accumulation of static electricity in the drywall sander 1, but also has the effect of neutralizing the static electricity accumulated on the workpiece surface K and suppressing the adhesion of the dust that is not collected and scattered to the workpiece surface K. The contact part 192 in the arm part 190 is in the shape of a leaf spring and exhibits an elastic action, so that the contact part 192 surely contacts the first hose 94. In addition, the conductive plate 87 is efficiently and surely fixed to the gear housing 74 by using the screw 105 for fixing the gear housing 74 to the motor housing 72. The insertion part 195 is surely fixed to the gear housing 74 by the hole 196 into which the protrusion 198 fits. Therefore, the rotation of the head part cover 83 etc. is made smoothly even when the insertion part 195 is inserted.

[0053] The above drywall sander 1 includes a head portion 8 having an electric motor 78 and a pad 82 that moves by the driving force of the electric motor 78, and a rod portion 2 having the head portion 8 connected to an end portion thereof and extending in the front-rear direction. The head portion 8 has a vertical wall portion G surrounding the radially outer side of the pad 82, and a grounding member 86 disposed between the vertical wall portion G and the pad 82 and surrounding the radially outer side of the pad 82. The grounding member 86 has a brush mounting portion 180 and a brush 184 disposed below the brush mounting portion 180. The lower end of the brush 184 is located below the lower end of the vertical wall portion G. The brush mounting portion 180 has a through hole H1 extending in the radial direction of the pad 82. Therefore, a long rod type grinding machine is provided that suppresses leakage and dropping of the dust D1.

[0054] Further, the through hole H1 is disposed above the lower end of the vertical wall portion G. Therefore, the time for the wind W2 to contact the rotating pad 82 is shortened, and a situation where the wind speed of the wind W2 decreases due to the influence of the rotating pad 82 is suppressed, and the suppressing effect of leakage and dropping of the dust is ensured. Furthermore, the brush mounting portion 180 has a brush mounting portion main body base portion 185A and a brush mounting portion main body wall portion 185B. The brush 184 and the brush mounting portion main body wall portion 185B face the same direction. The through hole H1 is disposed between the brush mounting portion main body base portion 185A and the brush mounting portion main body wall portion 185B and is disposed radially inward of the brush 184. Therefore, the wind W1 is rectified by passing between the hairs of the hair bundle 188 of the brush 184, and the accumulation of the dust D1 is suppressed more efficiently. Still further, a plurality of through holes H1 are provided side by side in the circumferential direction, and the total circumferential length of all the through holes H1 is larger than the total circumferential length of the portions (all the connecting portions 187) between all the through holes H1. Therefore, the air volume of the wind W1 for blowing away the dust D1 is ensured.

[0055] In addition, the head portion 8 includes a head portion cover 83 and an air guide member 85 attached below the head portion cover 83. The vertical wall portion G includes a vertical wall base portion 171 that is a part of the head portion cover 83 and a vertical wall extension portion 179 that is part or all of the air guide member 85. The vertical length of the vertical wall extension portion 179 is longer than the vertical length between the lower end of the vertical wall extension portion 179 and the lower end of the brush 184. Therefore, the space between the work surface K such as the wall B and the lower end of the vertical wall extension portion 179 can be made narrower, and accordingly, the wind speed of the air flow W1 can be increased, further suppressing the leakage and fall of the dust D1 more efficiently. Also, depending on the state of the work surface K and the like, the processing can be performed with the air guide member 85 removed. Also, the air guide member 85 is an elastic body. Therefore, even if the air guide member 85 contacts the work surface K, a situation where the work surface K is damaged such as scratched is suppressed. Also, even if an impact occurs when the air guide member 85 contacts the work surface K, the drywall sander 1 is protected from the impact. Furthermore, the material of the air guide member 85 exhibits non-polluting properties. Therefore, even if the air guide member 85 contacts the work surface K, a situation where the work surface K is soiled is suppressed.

[0056] Furthermore, the head portion 8 has a head portion cover 83 that covers above the grounding member 86, and the head portion cover 83 has an upper through hole H2 in the upper portion above the grounding member 86. Therefore, the accumulation of dust D2 inside the head portion cover 83 is suppressed more efficiently. Also, a plurality of through holes H1 are provided side by side in the circumferential direction, and the set of through holes H2 is arranged to extend over the entire circumference of the brush mounting portion. Therefore, no matter what rotational position the head portion cover 83 is in, or no matter how the pole portion 2 is positioned relative to the head portion 8, one of the through holes H1 is arranged at the lower part during the processing of the wall B, and the dust D1 accumulated at the lower part is surely blown away. Furthermore, the head portion 8 has a head portion housing 88, and the grounding member 86 is rotatably provided around a virtual rotation axis in the vertical direction with respect to the head portion housing 88 (gear housing 74) via the head portion cover 83. Therefore, even if the head portion cover 83 and the grounding member 86 hit the ceiling during the processing of the wall B, the head portion cover 83 and the grounding member 86 rotate with respect to the gear housing 74. Accordingly, the head portion cover 83 and the grounding member 86 are in a state of rolling on the ceiling surface, and the movement of the head portion 8 becomes smooth. Also, the head portion 8, and thus the drywall sander 1, is protected from the impact caused by a collision with the ceiling or the like.

[0057] Note that the first embodiment of the present disclosure is not limited to the above-described embodiments and modification examples. For example, the embodiment of the present disclosure may appropriately have the following further modification examples with respect to the above-described embodiments and modification examples. The vertical wall portion G may be formed of one member or may be formed of three or more members. Each tuft 188 of the brush 184 may be arranged along a virtual circle for arranging single or triple or more tufts, or may be arranged in a state other than zigzag. The grounding member 86 may be divided into a plurality of parts in the circumferential direction. For example, the grounding member 86 may include a grounding member base portion occupying about three-quarters of the entire circumference and a grounding member attachment that is detachable therefrom and occupies about the remaining one-quarter.

[0058] The number of stages of the planetary gear mechanism 80 may be 1 or may be 3 or more. Also, another type of speed reduction mechanism may be used. The installation number, arrangement, size, etc. of at least any one of the ventilation hole 58, the inner exhaust port 137, the outer exhaust port 138, and the intake port 139 can be variously changed. For the fan 136, a fan of a type other than a centrifugal fan may be used. The electric motor 78 may be an outer rotor type or may be a brushed motor. The electric motor 78 may be connected to a commercial power supply via a power cord and may be driven by AC. The pad 82 may move eccentrically via an eccentric spindle. Also, the shape of the pad 82 may be triangular or the like. The pad 82 may have a polished surface (machining working part) in advance. In this case, the pad 82 becomes the tip tool T.

[0059] At least any one of the numbers of various bearings, screws, and buttons may be increased or decreased, a reverse switch may be used instead of the button, the pinion 125 may be replaced with a belt and pulley, the screw may be made into a rivet, the motor housing 72 and the gear housing 74 may be integrated, the front handle housing 14 and the rear handle housing 15 may be integrated, the battery 50 may be made rechargeable in the battery mounting part 26, a disposable battery may be used, etc. At least any one of the functions, arrangements, types, forms, and numbers of various members or parts may be appropriately changed. Furthermore, the present disclosure can be applied to a long pole type polisher or grinder, other long pole type grinders such as a long pole type concrete cutter, or other long pole type grinders to which a dust collector can be connected.

[0060] [Second Embodiment] FIG. 10 is a central longitudinal sectional view of the front part of a drywall sander according to the second embodiment of the present disclosure. FIG. 11 is an enlarged sectional view of a head part cover 83, an air guide member 85, a grounding member 86, and a rectifying plate 210 in the drywall sander according to the second embodiment of the present disclosure. The section of FIG. 11 is the same as FIG. 7 according to the first embodiment. FIG. 12A is an upper perspective view of the rectifying plate 210 according to FIG. 11. FIG. 12B is a lower perspective view of the rectifying plate 210 according to FIG. 11. The drywall sander according to the second embodiment is the same as the first embodiment except for the differences in the stopper 84 and the rectifying plate 210 in the head part 8,208, and the presence or absence of the upper through hole H2. Members and parts that are the same as those in the first embodiment in the second embodiment are denoted by the same reference numerals as those in the first embodiment, and the description thereof is appropriately omitted.

[0061] In the head part 208 of the second embodiment, the upper through hole H2 is not opened in the head part cover 83. Also, in the head portion 208, a disk-shaped flow rectifying plate 210 having a central hole and spreading in the front-back, left-right directions similar to the pad 82 is provided between the pad 82 and the lower portion of the gear housing 74. A cylindrical central wall portion 212 that protrudes upward with respect to other portions is erected at the peripheral portion of the central hole of the flow rectifying plate 210. The flow rectifying plate 210 is fixedly and non-rotatably attached to the lower portion inside the disk-shaped portion of the gear housing 74. The flow rectifying plate 210 is provided in place of the stopper 84 in the first embodiment, and the head portion cover 83 rotates around a virtual rotation axis in the vertical direction with respect to the lower portion of the gear housing 74 and the flow rectifying plate 210. The spindle 81 and the screw 168 are arranged inside the central hole of the flow rectifying plate 210. The front portion of the central wall portion 212 is along the space S between the outer housing 70 of the head portion and the motor housing 72 and the space communication hole 214 in the lower portion of the gear housing 74. The flow rectifying plate 210 is not in contact with the pad 82 and does not interfere with the movement of the pad 82. Also, the edge of the flow rectifying plate 210 is disposed below the head portion cover 83. The gap between the upper surface of the flow rectifying plate 210, the lower surface of the head portion cover 83, and the lower surface of the gear housing 74 corresponds to the second route of the dust collection passage in the first embodiment. Note that the edge of the flow rectifying plate 210 does not have to reach below the head portion cover 83.

[0062] Such a drywall sander of the second embodiment operates as follows, for example. Also in the drywall sander of the second embodiment, the wind W1 in the second route of the dust collection passage is generated, and the wind W2' in the third route is generated by branching from the wind W1 outside the radial direction of the main body base portion 185A of the brush attachment portion. These winds W1 and W2' merge inside the radial direction of the main body base portion 185A of the brush attachment portion, enter between the head portion cover 83 and the flow rectifying plate 210, pass through the space between the lower portion of the gear housing 74 and the flow rectifying plate 210 as the wind W3, and reach the space communication hole 214. The wind W1 mainly suppresses the accumulation of the dust D1. The wind W2' mainly suppresses the accumulation of the dust D2. The wind W3 passes between the lower part of the non-rotating gear housing 74 and the non-rotating rectifying plate 210. Therefore, the wind W3 is less likely to be affected by the rotation of the pad 82 and becomes even more stable.

[0063] The head portion 208 in the second form of the drywall sander has a head portion housing 88 (gear housing 74) disposed above the pad 82, and a rectifying plate 210 that spreads in the same manner as the pad 82 is provided between the pad 82 and the head portion housing 88. Therefore, the winds W1 and W2' that suppress the accumulation of the dust D1 and D2 become even more stable.

[0064] In addition, the second form of the present disclosure appropriately has the same modification examples as the first form. Further, the rectifying plate 210 may be formed by combining a plurality of divided portions. Furthermore, the rectifying plate 210 may rotate together with the head portion cover 83. In the second form, an upper through-hole H2 may be provided.

Description of Reference Numerals

[0065] 1 ·· Drywall sander (long pole type grinder), 2 ·· Pole portion, 8, 208 ·· Head portion, 78 ·· Electric motor, 82 ·· Pad, 83 ·· Head portion cover, 85 ·· Air guide member, 86 ·· Grounding member, 88 ·· Head portion housing, 171 ·· Base of vertical wall, 179 ·· Extension of vertical wall, 180 ·· Brush mounting portion, 184 ·· Brush, 185A ·· Main body base portion of brush mounting portion, 185B ·· Wall portion of brush mounting portion main body, 187 ·· Connection portion (portion between through-holes H1), 188 ·· Bristle bundle, 210 ·· Rectifying plate, D1, D2 ·· Dust, G ·· Vertical wall portion, H1 ·· Through-hole, H2 ·· Upper through-hole, K ·· Work surface, W1, W2 ·· Wind.

Claims

1. An electric motor, and a head portion having a pad that moves by the driving force of the electric motor, A rod portion having the head portion connected to an end portion and extending in the front-rear direction, Comprising: The head portion is A grounding member surrounding the radially outer side of the pad, A head portion cover disposed above the grounding member, Having: The head portion cover has a vertical wall portion surrounding the radially outer side of the pad, The grounding member is disposed with a gap from the vertical wall portion between the vertical wall portion and the pad, and has a brush mounting portion and a brush disposed below the brush mounting portion, The lower end of the brush is located below the lower end of the vertical wall portion, The brush mounting portion has a through hole extending in the radial direction of the pad, a brush mounting portion main body base portion extending in the radial direction of the pad, a brush mounting portion main body wall portion having a smaller diameter than the brush mounting portion main body base portion, and a connection portion connecting the upper portions of the brush mounting portion main body base portion and the brush mounting portion main body wall portion, The brush and the brush mounting portion main body wall portion face the same direction, The through hole is disposed between the brush mounting portion main body base portion and the brush mounting portion main body wall portion and is disposed radially inward of the brush, A long pole type grinding machine characterized by the above.

2. The brush has a plurality of tufts of hair, The tufts of hair are disposed radially outside the through hole, The long pole type grinding machine according to claim 1, characterized by the above.

3. The through hole is disposed above the lower end of the vertical wall portion, The long pole type grinding machine according to claim 1 or claim 2, characterized by the above.

4. A plurality of the through holes are provided side by side in the circumferential direction, The total circumferential length of all the through holes is larger than the total circumferential length of the portions between all the through holes, The long pole type grinding machine according to any one of claims 1 to 3, characterized by the above.

5. The head portion has an air guide member attached to the lower side of the head portion cover, The vertical wall portion includes a vertical wall base portion that is a part of the head portion cover and a vertical wall extension portion that is a part or all of the air guide member, The vertical length of the vertical wall extension portion is longer than the vertical length between the lower end of the vertical wall extension portion and the lower end of the brush, The long pole type grinding machine according to any one of claims 1 to 4, characterized by the above.

6. The air guide member is an elastic body The long rod-shaped grinding machine according to claim 5, characterized in that...

7. The material of the air guide member exhibits non-contaminating properties. The long rod-shaped grinding machine according to claim 5 or claim 6, characterized in that...

8. The head portion cover has an upper through-hole in the upper portion of the grounding member. The long rod-shaped grinding machine according to any one of claims 1 to 7, characterized in that...

9. A plurality of the through-holes are provided in a circumferentially arranged state. The set of the through-holes is arranged to extend over the entire circumference of the brush mounting portion. The long rod-shaped grinding machine according to any one of claims 1 to 8, characterized in that...

10. The head portion has a head portion housing. The grounding member is rotatably provided around a virtual rotation axis in the vertical direction with respect to the head portion housing. The long rod-shaped grinding machine according to any one of claims 1 to 9, characterized in that...

11. The head portion has a head portion housing disposed above the pad. A rectifying plate that spreads in the same manner as the pad is provided between the pad and the head portion housing. The long rod-shaped grinding machine according to any one of claims 1 to 10, characterized in that...

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