DUST BOX AND BELT SANDER

A dust box is provided that is configured to be removably mounted to a belt sander having a housing, and a discharge nozzle and a suction nozzle that are connected to the housing. The dust box has a first nozzle configured to be connected to the discharge nozzle, a second nozzle configured to be connected to the suction nozzle, a container part formed of synthetic resin and connected to the first and second nozzles, and a filter. The filter is configured to separate dust from air. The filter is provided within the container part to partition an inside space of the container part into a first space that communicates with the first nozzle and a second space that communicates with the second nozzle.

CROSS REFERENCE TO RELATED ART

The present application claims priority to Japanese Patent Application No. 2022-46450 filed on Mar. 23, 2022, the disclosure of which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to a dust box configured to be removably mounted to a belt sander, and a belt sander having the dust box.

BACKGROUND

Japanese Unexamined Patent Application Publication No. H11-291170 discloses a belt sander in which dust generated by working operation can be collected in a dust collecting bag. This belt sander has a dust collection port that is provided behind a drive roller in a lower part of a housing, a dust collection passage that is provided within the housing and communicates with the dust collection port, a discharging tube that communicates with the dust collection passage, and a dust bag that is mounted to the discharging tube via a cuff. The dust collection passage is formed in the dust collection passage so as to surround the motor shaft and a dust collecting fan. Dust is sucked from the dust collection port by rotation of the dust collecting fan and stored in the dust bag through the dust collection passage, the discharging tube and the cuff. The belt sander further has an earth plate that is configured to be electrically connected to an inside body simultaneously with mounting of the cuff, thereby suppressing electrostatic charging of the dust during dust collection.

SUMMARY

It is however desired to improve the dust collecting efficiency in a dust box configured to be removably mounted to a belt sander.

According to a first aspect of the present disclosure, a dust box is provided that is configured to be removably mounted to a belt sander, the belt sander having a belt driving part configured to rotate an endless sanding belt, and a housing that has a discharge nozzle and a suction nozzle and houses an electric motor for driving the belt driving part and a dust collecting fan. The dust box has a first nozzle configured to be removably connected to the discharge nozzle, a second nozzle configured to be removably connected to the suction nozzle, a container part formed of synthetic resin and connected to the first and second nozzles, and a filter that is configured to separate dust from air. The filter is arranged within the container part to partition an inside space of the container part into a first space that communicates with the first nozzle and a second space that communicates with the second nozzle.

According to this aspect, the first and second nozzles of the dust box are respectively connected to the discharge nozzle and the suction nozzle of the belt sander, and air within the dust box is sucked into the suction nozzle via the second nozzle when the dust collecting fan rotates. Further, dust generated by working operation is discharged from the discharge nozzle of the belt sander into the dust box via the first nozzle. At this time, the pressure inside the dust box becomes negative by air suction, so that the dust box according to the first aspect provides improved dust collecting efficiency. Further, by provision of the filter that partitions the inside space of the container part into the first space that communicates with the first nozzle and the second space that communicates with the second nozzle, dust is stored within the dust box and restrained from entering the housing from the second nozzle.

According to a second aspect of the present disclosure, a belt sander having the dust box removably mounted thereto is provided.

According to this aspect, the belt sander having the dust box removably mounted thereto provides improved dust collecting efficiency.

DETAILED DESCRIPTION OF THE EMBODIMENT

In one non-limiting embodiment according to the present disclosure, the filter may be arranged closer to the second nozzle than to the first nozzle within the container part.

According to this embodiment, the first space in which dust is stored can be secured large relative to the second space that communicates with the second nozzle, while dust is restrained from entering the housing from the second nozzle.

In addition or in the alternative to the preceding embodiment, the belt driving part may include a drive roller that is rotated by the motor, and a driven roller. Where a direction in which a rotational axis of the drive roller and a rotational axis of the driven roller extend is defined as a left-right direction, a direction in which the drive roller and the driven roller are arranged in parallel is defined as a front-rear direction, and a direction orthogonal to the left-right direction and the front-rear direction is defined as an up-down direction, a polishing surface may be defined by a lower surface of the sanding belt. The dust box may be configured such that when the dust box is mounted to the belt sander, the first nozzle is located below the second nozzle, and the first space may be a lower space within the container part.

According to this embodiment, the first nozzle is arranged below the second nozzle and the first space is provided in a lower part within the container part, so that a dust collecting path from the lower surface (polishing surface) of the sanding belt into the container part can be shorter. Thus, the dust collecting efficiency is improved.

In addition or in the alternative to the preceding embodiments, the first and second nozzles may be open in the same direction.

According to this embodiment, compared with a structure in which the first and second nozzles are open in different directions, air flow within the container part can be smoother, so that the dust collecting efficiency is more improved.

In addition or in the alternative to the preceding embodiments, the filter may be a bag-like air filter having an open end.

According to this embodiment, dust can be efficiently separated from air by the filter.

In addition or in the alternative to the preceding embodiments, the container part may have a nozzle connection part that is connected to the first and second nozzles, and a body part that is removably fitted to the nozzle connection part. The filter may be provided on the nozzle connection part.

According to this embodiment, dust stored in the container part can be removed by detaching the body part from the nozzle connection part.

In addition or in the alternative to the preceding embodiments, the dust box may further have an attaching/detaching part configured to attach and detach the body part to and from the nozzle connection part.

According to this embodiment, the user need not separately prepare a tool for attaching and detaching the body part to and from the nozzle connection part, so that the convenience in use of the dust box is improved.

In addition or in the alternative to the preceding embodiments, at least part of the dust box may be formed of conductive synthetic resin.

According to this embodiment, the dust collecting efficiency is improved in the dust box at least part of which is formed of conductive synthetic resin.

In addition or in the alternative to the preceding embodiments, where an up-down direction is defined with the side of the belt sander on which the belt driving part is arranged being defined as a lower side and the opposite side defined as an upper side, at least part of the container part that is located below a central position of the container part in the up-down direction when the dust box is mounted to the belt sander may be formed of the conductive synthetic resin.

According to this embodiment, the dust collecting efficiency is improved in the dust box at least part of which is formed of conductive synthetic resin.

In addition or in the alternative to the preceding embodiments, the dust box may further have an earth member (a ground member). The earth member may be provided on the dust box such that its one end part is connected to the part formed of the conductive synthetic resin, and the other end part is exposed outside the dust box.

According to this embodiment, electric charge charged (accumulated) in the dust box is discharged by the earth member. This suppresses adhesion of dust to a certain place of the dust box, so that the dust collecting efficiency is improved.

In addition or in the alternative to the preceding embodiment, a belt sander to which the dust box is removably mounted is provided. The belt sander may include an electric motor, a dust collecting fan, a housing that houses the motor and the dust collecting fan, and a belt driving part. The belt driving part may include a drive roller configured to be rotated by the motor, and a driven roller, and may be configured to drive an endless sanding belt looped over the drive roller and the driven roller. Where a direction in which a rotational axis of the drive roller and a rotational axis of the driven roller extend is defined as a left-right direction, a direction in which the drive roller and the driven roller are arranged in parallel is defined as a front-rear direction, and a direction orthogonal to the left-right direction and the front-rear direction is defined as an up-down direction, the belt driving part may be arranged below the housing. The housing may have a discharge nozzle and a suction nozzle. The discharge nozzle may be configured to discharge dust generated by the working operation from the housing. The suction nozzle may be configured to suck air from the dust box into the housing. The housing may further have a dust collection port, an air outlet, a first passage that connects the dust collection port and the discharge nozzle, and a second passage that connects the suction nozzle and the air outlet. The dust collection port may be provided behind the belt driving part. The air outlet may be provided in the housing to communicate with a space where the dust collecting fan is housed. The first passage may be separated from spaces where the motor and the dust collecting fan are housed within the housing, and the second passage. The second passage may communicate with the space where the dust collecting fan is housed. The dust collecting fan may be configured to rotate to generate an air flow from the dust collection port toward the discharge nozzle through the first passage, and an air flow from the suction nozzle toward the air outlet through the second passage.

According to this embodiment, when the dust collecting fan rotates, dust generated by working operation is led together with air from the dust collection port to the first passage, the discharge nozzle, the first nozzle and the container part in this order. The filter is provided within the container part of the dust box, so that the possibility of dust passing through the filter and stored in the first space of the container part can be reduced. After separated from dust by the filter, air within the container part is led to the second nozzle, the suction nozzle and the second passage and discharged from the air outlet of the belt sander. Further, the first passage is separated from the spaces where the motor and the dust collecting fan are housed and the second passage, so that adhesion of dust to the motor and the dust collecting fan is suppressed. Therefore, the dust collecting efficiency is improved, and the life of the belt sander is elongated.

In addition or in the alternative to the preceding embodiments, the suction nozzle and the discharge nozzle may be open to the rear. The discharge nozzle may be arranged below the suction nozzle.

According to this embodiment, with the configuration in which the dust collection port is provided behind the belt driving part and the discharge nozzle is provided below the suction nozzle, the first passage from the dust collection port to the discharge nozzle can be relatively short, so that the dust collecting efficiency is further improved.

<The Overall Structure of the Belt Sander>

A belt sander1is now described as a representative embodiment according to the present disclosure. The belt sander1is capable of performing a working operation by driving a belt driving part6, which holds an endless sanding belt B, by a motor2, with the sanding belt B placed in contact (pressing contact) with a workpiece. In this embodiment, the belt sander1has a handle14. A user can perform a working operation on a desired part of the workpiece by holding the handle14and moving the belt sander1while placing the sanding belt B in contact with the workpiece. The belt sander1described in this embodiment is also called as an “up-handle belt sander”. The up-handle belt sander is a belt sander of a type that has the handle14and the motor2on a side opposite to a polishing (sanding) surface of the sanding belt B.

The overall structure of the belt sander1is now described with reference toFIGS.1to7. The belt sander1mainly includes a housing10, an electric motor2, a fan3, a power transmitting part35, a belt driving part6, a battery mounting part4and a switching mechanism8.

The belt driving part6includes a drive roller61, a driven roller62arranged on a side opposite to the drive roller61, and a support frame64(seeFIG.6) that supports the rollers61,62so as to be rotatable around their respective axes (rotational axes A1and A2). The drive roller61and the driven roller62are arranged in parallel, and the endless sanding belt B is looped over the drive roller61and the driven roller62. A plate for pressing the sanding belt B against a workpiece is arranged on a prescribed face of the support frame64. The drive roller61is rotated in a direction of arrow D (seeFIG.1) by the motor2.

In the following description, for convenience sake, the direction in which the drive roller61and the driven roller62are arranged in parallel is defined as a front-rear direction of the belt sander1. In the front-rear direction, the side of the belt driving part6on which the drive roller61is arranged is defined as a rear side and the side on which the driven roller62is arranged is defined as a front side. A direction that crosses the front-rear direction and in which rotational axes A1, A2of the drive roller61and the driven roller62extend is defined as a left-right direction of the belt sander1. Further, a direction orthogonal to the front-rear direction and the left-right direction is defined as an up-down direction of the belt sander1. In the up-down direction, the side of the belt sander1on which the belt driving part6is arranged is defined as a lower side, and the opposite side is defined as an upper side. A part of the sanding belt B that is exposed from the housing10functions as a polishing surface (sanding surface B1) for polishing a workpiece.

The housing10includes a body housing11and a side housing16.

The body housing11holds the belt driving part6with a lower end part of the belt driving part6exposed. The body housing11covers an upper part of the belt driving part6and an area behind a rear end part of the belt driving part6and substantially extends in the front-rear direction as a whole. In this embodiment, as shown inFIG.4, the body housing11is formed by two halves, or a left body housing11L and a right body housing11R, fixed together with screws.

As shown inFIG.2, the body housing11includes a first part12and a second part13in front of the first part12, directly above the belt driving part6.

The first part12is formed directly above the belt driving part6and on the rear side substantially from the central position of the belt driving part6in the front-rear direction. The first part12mainly houses the motor2. The first part12is also referred to as a “motor housing part”. The first part12has a generally box-like shape including an upper wall121, a front wall122, side walls123and a rear wall124. The upper wall121is substantially orthogonal to the up-down direction and substantially parallel to the sanding surface B1. The front wall122and the rear wall124are substantially orthogonal to the front-rear direction. The upper wall121may just be configured to, when the belt sander1is used in a second use mode, be placed on a desk or the like which may have a slightly uneven surface.

The second part13is formed directly above the belt driving part6and on the front side substantially from the central position of the belt driving part6in the front-rear direction. The second part13has side walls133formed continuously to the side walls123of the first part12. The upper wall131of the second part13is located below the upper wall121of the first part12. Thus, a part of the body housing11that is located above the belt driving part6has a stepped shape. The battery mounting part4is provided on the second part13.

A part of the body housing11that extends rearward from the first part12forms the handle14extending in the front-rear direction. The handle14is connected to the first part12and extends in the front-rear direction. In this embodiment, the handle14is connected to an upper part of the rear wall124of the first part12and extends rearward and downward from the first part12. An upper end of the handle14dose not protrude upward from the upper wall121of the first part12. In this embodiment, the upper end of the handle14is located substantially in the same position as the upper wall121in the up-down direction. The handle14is also referred to as a “first handle”.

A rear end part of the handle14is bent downward. The bent part is connected to a rear lower part of the first part12. Thus, a rear part of the body housing11behind the belt driving part6has an annular shape.

A lower part of the handle14of the body housing11, via which the rear end part of the handle14is connected to a part of the body housing11behind the belt driving part6, forms a controller housing part15. A front end part (directly behind the belt driving part6) of the controller housing part15is curved along an outer edge of the drive roller61. The body housing11is open in the left-right direction directly behind the belt driving part6. This opening functions as a dust collection port19through which dust generated by working operation is introduced to a dust passage (a first passage191) provided within the housing10.

As shown inFIG.6, the switching mechanism8is provided behind the motor2within the body housing11. The switching mechanism8includes a first switch80, a second switch90, a first lock switch85and a second lock switch95(seeFIG.4), which can be manually operated by a user. The switching mechanism8will be described in detail below.

A dial39for adjusting the speed of the motor2is provided on an upper part of the body housing11behind the motor2. An upper end of the dial39is exposed from the upper wall121of the body housing11. The dial39is configured such that the attitude (rotational position) of the dial39can be changed by manual operation of a user. The dial39is connected to a controller5via wiring. The controller5is configured to set the speed of the motor2according to the rotational position of the dial39.

As shown inFIG.6, the controller5is mounted on a main board arranged within a case of the controller housing part15. In this embodiment, the controller5is configured as a microcomputer including a CPU and a memory. The controller5is configured to control various operations of the belt sander1, including drive control of the motor2. The controller5is connected to the battery mounting part4, the motor2and the first and second switches80,90of the switching mechanism8via wiring (not shown). The controller5is configured to supply power of a battery300mounted to the battery mounting part4, to the motor2when the first and second switches80,90are in an ON state. Then, the motor2is rotated and the belt driving part6is driven via the power transmitting part35. Thus, the sanding belt B is rotated in the direction of arrow D. Further, the controller5is configured not to supply power to the motor2when at least one of the first and second switches80,90is in an OFF state.

Part of the left side wall123of the first part12is open and covered by the side housing16. As shown inFIGS.3and4, the side housing16includes a fan housing161for covering the left side of the fan3, a gear cover162for covering part of the power transmitting part35, and a belt cover163for covering an endless synchronous belt that is part of the power transmitting part35. The side housing16is fixed to the left body housing11L with screws.

The motor2is driven by power supplied from the battery300mounted to the battery mounting part4. In this embodiment, a brushless DC motor is used as the motor2. As shown inFIG.6, the motor2has a motor body21having a stator and a rotor, and a shaft22that extends from the rotor and rotates integrally with the rotor. The shaft22(a rotational axis A3of the shaft22) extends in the left-right direction. The shaft22is supported by the body housing11via a bearing.

As shown inFIG.7, the power transmitting part35is held by the side housing16and configured to transmit rotation of the shaft22to the drive roller61. The power transmitting part35includes a pulley part including a pulley integrally formed with a left end part of the shaft22, an endless synchronous belt and a gear mechanism for reducing the rotation speed of the shaft22.

The fan3is configured to have a function of cooling the motor2and a function as a dust collecting fan. The fan3generates an air flow for cooling the motor2and an air flow for sucking dust generated by working operation into the housing10and discharging the dust into a dust box200.

In this embodiment, the fan3is housed on the left side of the motor body21mostly in the first part12of the body housing11. The fan3is fixed between the motor body21and a bearing onto the shaft22and rotates integrally with the shaft22. Part of the left wall123of the first part12is open as described above, and a back side of the fan3is covered by the side housing16(a fan housing161). A front part of the fan housing161is curved along an outer edge of the fan3. A plurality of small openings (air outlets165) are formed in the curved part of the fan housing161(seeFIGS.4and7, for example).

The fan3of this embodiment is configured as a centrifugal fan. The fan3sucks air from the back side of the fan3(the left side of the belt sander1) and discharges the air radially in a direction crossing the rotational axis A3of the shaft22. The discharged air is led to the motor2by a plurality of small blades formed on a front side of the fan3(on the right side of the belt sander1) and a baffle plate32provided on the front side of the fan3. Further, a guide plate31is provided on the back side of the fan3and connected to a suction nozzle150(described below). When the fan3is rotated, the fan3sucks air from the back side and radially discharges the air and then sends the discharged air to the motor2, as well as sending air within the housing10to the air outlets165.

<The Structures of the Dust Box and the Belt Sander for Collecting Dust in the Dust Box>

The belt sander1of this embodiment is configured such that the dust box200is removably mounted thereto. The structure of the belt sander1for collecting dust in the dust box200and the structure of the dust box200are now described.

As shown inFIGS.3and7, the housing10of the belt sander1has two tubular parts (a discharge nozzle140and a suction nozzle150). The discharge nozzle140and the suction nozzle150are formed on a rear upper part of the side housing16and extend in the front-rear direction. The discharge nozzle140and the suction nozzle150are arranged side by side in the up-down direction, and the discharge nozzle140is arranged below the suction nozzle150. The discharge nozzle140and the suction nozzle150are open to the rear.

As described above, the body housing11has the dust collection port19that is open in the left-right direction directly behind the belt driving part6. The first passage191for communication between the dust collection port19and the discharge nozzle140is formed within the housing10. In this embodiment, the first passage191is defined by a partition101provided within the housing10and a tubular wall of the discharge nozzle140. The partition101is provided continuously within a rear lower part of the body housing11, a rear part of the gear cover162and a rear part of the fan housing161. The first passage191is separated from spaces where parts including the motor2, the fan3and the power transmitting part35are housed, by the partition101and the tubular wall of the discharge nozzle140. Therefore, the possibility of air and dust flowing through the first passage191entering the housing parts (spaces) for the motor2, the fan3and the power transmitting part35is reduced.

As shown inFIG.7, a second passage192for communication between the suction nozzle150and the air outlets165is formed within the housing10. The second passage192communicates with the space where the fan3is housed within the housing10. The second passage192is mainly defined by a tubular wall of the suction nozzle150, the guide plate31, and a wall part102forming the fan housing161.

The structure of the dust box200is now described with reference toFIGS.7to11. The dust box200is formed to extend in a prescribed direction as a whole. The dust box200has a first nozzle210and a second nozzle220that extend in this prescribed direction, a container part230connected to the first and second nozzles210,220, and a filter260provided within the container part230. The first and second nozzles210,220and the container part230are formed of an air impermeable (airtight) material. In this embodiment, the first and second nozzles210,220and the container part230are formed of conductive synthetic resin.

InFIG.8, the up-down direction, the front-rear direction and the left-right direction are shown for the dust box200attached to the belt sander1. The dust box200attached to the belt sander1extends in the front-rear direction as a whole. The first and second nozzles210,220extend in the front-rear direction and are open to the front. The first and second nozzles210,220are arranged side by side in the up-down direction, and the first nozzle210is arranged below the second nozzle220. The dust box200is attached to the belt sander1by inserting the first and second nozzles210,220respectively into the discharge nozzle140and the suction nozzle150of the belt sander1. The first passage191of the belt sander1communicates with the inside of the first nozzle210(the inside of the dust box200) by insertion of the first nozzle210into the discharge nozzle140. The second passage192of the belt sander1communicates with the inside of the second nozzle220(the inside of the dust box200) by insertion of the second nozzle220into the suction nozzle150. Further, O-rings212,222are fitted onto outer peripheral walls of the first and second nozzles210,220, respectively, so that the connection parts of these nozzles are kept airtight.

The container part230has a generally box-like shape extending in the front-rear direction. The length of the container part230in the left-right direction is shorter than the lengths of the container part230in the up-down direction and in the front-rear direction. An upper wall (an upper surface231) of the container part230is substantially orthogonal to the up-down direction. A lower wall (a lower surface234) of the container part230is inclined rearward and upward. As shown inFIG.4, the container part230is located on the left side of the handle14and the controller housing part15with the dust box200attached to the belt sander1.

The dust box200is configured to be fitted within the widths (lengths) of the housing10in the up-down direction and the left-right direction when attached to the belt sander1. Further, the dust box200is configured such that the lower surface234is located above the sanding surface B1in the up-down direction when attached to the belt sander1. In this embodiment, as shown inFIG.4, a left side surface233of the container part230is located substantially in the same position in the left-right direction as a left surface of the housing10(a left surface of the fan housing161). Further, as shown inFIG.7, the upper surface231of the container part230is located substantially in the same position in the up-down direction as an upper end (the upper wall121) of the belt sander1.

The container part230is configured to be divided into a nozzle connection part240and a body part250. The nozzle connection part240is a front part of the container part230and is connected to the first and second nozzles210,220. In this embodiment, the nozzle connection part240is integrally formed with the first and second nozzles210,220. As shown inFIG.10, the first and second nozzles210,220and the nozzle connection part240are formed by two halves, or a left nozzle part240L and a right nozzle part240R, fixed together with screws. An O-ring244is fitted onto an outer periphery of a rear end part243of the nozzle connection part240.

The body part250is a rear part of the container part230. The body part250has a generally box-like shape having an open front end. In this embodiment, the container part230is formed of carbon resin. As shown inFIG.9, the container part230has a window part235formed of light transmitting resin. A user can visually check the amount of dust within the container part230via the window part235.

As shown inFIG.9, the dust box200further has an attaching/detaching part270configured to attach and detach the body part250to and from the nozzle connection part240. In this embodiment, the attaching/detaching part270includes a mounting screw271provided on the body part250, and an engagement part245provided on the nozzle connection part240. The mounting screw271has a knob272and a shaft273. The engagement part245is configured to be engaged with a front end part274of the mounting screw271.

A tubular part258is provided inside the body part250and extends forward from a rear wall232of the container part230. The tubular part258has a rear end opening formed in the rear wall232. The knob272is arranged on the rear side of the rear wall232and covers this opening. The shaft273is connected to the knob272and arranged within the tubular part258. The nozzle connection part240has a partition241provided between the first nozzle210and the second nozzle220in the up-down direction, and the engagement part245is formed by an opening formed in the partition241and engagement members including a nut246arranged in the opening. The partition241partitions the inside of the nozzle connection part240into a space that communicates with the first nozzle210and a space that communicates with the second nozzle220.

A method of fitting the body part250to the nozzle connection part240is now described. A user positions and aligns the body part250having the mounting screw271mounted thereto and the nozzle connection part240with each other such that an external contour (for example, the side surface233) formed by connecting the body part250and the nozzle connection part240is continuous. The user then inserts the front end part274of the shaft273into the opening of the engagement part245while fitting a front end part253of the body part250into the rear end part243of the nozzle connection part240. When the user manually operates (turns) the knob272, the front end part274of the shaft273is inserted into the opening of the engagement part245and engaged (fitted) with the engagement part245. In this manner, the body part250is fitted to the nozzle connection part240.

The filter260is arranged within the container part230so as to partition the space inside the container part230into a first space281that communicates with the first nozzle210and a second space282that communicates with the second nozzle220. The filter260is arranged closer to the second nozzle220than to the first nozzle210. The filter260is configured to allow air to pass therethrough but not to allow dust generated by working operation to pass therethrough. In this embodiment, a bag-like air filter having an opening261is used as the filter260. The air filter is, for example, a filter for coarse dust.

In this embodiment, a frame262is arranged inside the filter260. The frame262is configured to expand the filter260so as to keep the bag-like shape. As shown inFIG.9, a groove242is formed behind the second nozzle220above the partition241in an inner wall of the nozzle connection part240and configured such that the frame262is removably fixed thereto. The filter260is fixed to the groove242via the frame262such that the opening261faces the second nozzle220side (forward). It can also be said that the filter260is mounted to a part (second nozzle connection part) of the nozzle connection part240that is connected to the second nozzle220. As shown inFIG.10, a plate247extending rearward from the partition241supports a lower end part of the filter260.

The dust box200further has a string-like earth (ground) member265. The earth member265is provided to keep the potential of the dust box200equal to that of the ground. One end part of the earth member265is arranged in contact with the container part230and the other end part is exposed from the container part230. The length of exposure of the earth member265is set such that the other end part of the earth member265can come into contact with a workpiece or an object on the same plane as the workpiece when the sanding surface B1is placed on the workpiece. In this embodiment, the earth member265is arranged in a lower end part of the nozzle connection part240so as to be apart from the space (the first space281) of the container part230. The earth member265discharges electric charge accumulated in the dust box200.

Effects of the dust box200and the belt sander1having the dust box200attached thereto according to this embodiment are now described as well as the manner in which dust is stored (collected) in the dust box200.

When the dust box200is attached to the belt sander1by connecting the first and second nozzles210,220of the dust box200respectively to the discharge nozzle140and the suction nozzle150of the belt sander1, the first passage191of the belt sander1communicates with the first space281of the dust box200, and the second passage192of the belt sander1communicates with the second space282of the dust box200. As described above, the first space281is separated from the second space282by the filter260, so that air within the dust box200is allowed to move between the first and second spaces281,282.

When the belt sander1is driven, the fan3rotates and sucks air from the back side. At this time, by air suction of the fan3, air around the fan3is led from the suction nozzle150toward the air outlets165. In other words, by rotation of the fan3, air flow F2is generated from the inside of the dust box200toward the air outlets165through the second passage192(seeFIG.7). Further, the pressure inside the dust box200becomes negative by air suction of the fan3, so that air flow F1is generated from the dust collection port19(provided behind the belt driving part) toward the inside of the dust box200through the first passage191. Therefore, dust generated by working operation is led from the dust collection port19to the first passage191, the discharge nozzle140, the first nozzle210, and the first space281of the container part230, in this order. Dust flowing into the container part230is prevented from moving into the second space282by the filter260and thus stored in the first space281. In this manner, dust is stored in the first space281. Further, air within the dust box200passes through the filter260and flows from the first space281to the second space282, the second nozzle220, the suction nozzle150, the second passage192and the air outlets165, in this order, and then the air is discharged to the outside of the belt sander1.

Thus, according to this embodiment, when the first and second nozzles210,220of the dust box200are respectively connected to the discharge nozzle140and the suction nozzle150of the belt sander1and the fan3is rotated, air flow is generated from the dust collection port19of the belt sander1toward the air outlets165of the belt sander1through the inside of the dust box200. Further, the filter260partitions the space of the container part230into the first space281that communicates with the first nozzle210and the second space282that communicates with the second nozzle220, so that dust is stored in the dust box200and restrained from entering the housing10from the second nozzle220. Therefore, the dust box200and the belt sander1having the dust box200attached thereto according to this embodiment provide improved dust collecting efficiency.

As described above, the first passage191is separated from the spaces where parts including the motor2, the fan3and the power transmitting part35are housed, by the partition101and the tubular wall of the discharge nozzle140. Therefore, air and dust flowing through the first passage191does not enter the housing parts (spaces) for the motor2, the fan3and the power transmitting part35. Further, air flows from the dust box200into the second passage192after dust is removed from the air by the filter260. Therefore, adhesion of dust generated by working operation to the motor2, the fan3and the power transmitting part35within the housing10is suppressed, so that the life of the belt sander1is elongated.

In the dust box200, the first nozzle210through which dust enters is arranged below the second nozzle220through which air is sucked. Therefore, dust need not be transferred up to an upper part within the container part230, so that a path for storing dust within the container part230can be shorter. Thus, the dust collecting efficiency is improved.

The filter260is fixed to the groove242formed behind the second nozzle220, via the frame262. Thus, the filter260is arranged closer to the second nozzle220than to the first nozzle210. Therefore, the first space281in which dust is stored can be formed large relative to the second space282that communicates with the second nozzle220.

The first and second nozzles210,220are arranged side by side in the up-down direction and are open to the rear. This structure suppresses complication of air flow within the container part230that may be caused by a structure in which the first and second nozzles210,220are open in different directions. Therefore, air flow within the container part230can be smoother, so that the dust collecting efficiency is more improved.

Further, the container part230has the nozzle connection part240that is connected to the first and second nozzles210,220, and the body part250that is removably fitted to the nozzle connection part240, and the filter260is mounted to the nozzle connection part240. Therefore, dust stored within the container part230can be removed by detaching the body part250from the nozzle connection part240.

Dust, which is blocked by the filter260when air flows into the filter260(the second space282), may adhere to an outer surface of the filter260. In this embodiment, however, the filter260is mounted to the nozzle connection part240, so that a user can easily remove dust adhered to the outer surface of the filter260when detaching the body part250from the nozzle connection part240. Thus, the filter260can be avoided from being covered with dust, so that the dust collecting efficiency is more improved.

The dust box200has the attaching/detaching part270configured to attach and detach the body part250to and from the nozzle connection part240. Therefore, the user need not separately prepare a tool for attaching and detaching the body part250to and from the nozzle connection part240, so that the convenience in use of the dust box200is improved.

In the belt sander1, dust flows through the first passage191within the housing10, so that static electricity is easily generated by friction between the dust and the housing10. In this embodiment, however, the dust box200has the earth member265having one end part arranged in contact with the container part230formed of conductive synthetic resin, and the other end part exposed from the container part230. Therefore, the generated static electricity is discharged via the earth member265. Thus, dust is avoided from staying in a certain place of the dust box200by the static electricity, so that the dust collecting efficiency is further improved.

The dust box200is configured to be fitted within the widths (lengths) of the housing10in the up-down direction and the left-right direction when attached to the belt sander1. With this configuration, the possibility that the working range of the belt sander1is restricted by contact of the dust box200with a structure such as a wall located on the right or left of the belt sander1is reduced. Further, when the belt sander1is used in the second use mode, the possibility that the dust box200comes into contact with a desk or the like on which the belt sander1is placed is reduced.

<Other Embodiments of the Dust Box and the Belt Sander for Collecting Dust in the Dust Box>

The dust box200may only have the first nozzle210configured to be connected to the discharge nozzle140, the second nozzle220configured to be connected to the suction nozzle150, the container part230and the filter260. The shapes and materials of these parts may be different from those of the above-described embodiment. For example, the container part230may be formed of bag-shaped vinyl. The filter260may only be formed to allow air to pass therethrough but not to allow dust generated by working operation of the belt sander1to pass therethrough.

In the above-described embodiment, the opening261of the filter260is mounted to a part (the second nozzle connection part) of the nozzle connection part240that is connected to the second nozzle220, but the filter260may be mounted to the second nozzle220.

<The Structure of the Switching Mechanism>

The overall structure of the switching mechanism8is now described. The switching mechanism8is configured to be manually operated by a user to switch between driving and stopping of the motor2and thereby switch between driving and stopping of the belt sander1. As shown inFIG.6, the switching mechanism8includes the first switch80, the second switch90, the first lock switch85and the second lock switch95. InFIGS.14to18, a plane P1including a longitudinal axis of the handle14and orthogonal to the left-right direction is shown as an imaginary plane for the purpose of explaining the structure of the switching mechanism8.FIG.12is a sectional view of the switching mechanism8taken along the plane P1in the state (normal state) where the belt sander1is stopped.

As shown inFIG.12, part of the first switch80protrudes downward from an opening144formed in a front lower part of the handle14. The first switch80is configured to be depressed relative to the handle14by a user. The first switch80is also referred to as a depressing switch or a trigger switch. Part of the second switch90protrudes upward from an opening149formed in a rear upper part of the handle14. The second switch90is configured to be pushed relative to the handle14by a user. The first and second switches80,90are each configured as a momentary switch.

As shown inFIGS.4and12, the first lock switch85is provided in a front part of the handle14and configured to act on the first switch80. The first lock switch85is configured to have a function of restricting the first switch80from being turned on or placed in the ON state (a function of keeping the first switch80in the OFF state, a lock-off function). The first lock switch85is further configured to have a function of maintaining the ON state of the first switch80(a lock-on function). The first lock switch85is also referred to as a lock-on/lock-off switch. The second lock switch95is provided in a left rear part of the handle14and configured to act on the second switch90. The second lock switch95is configured to have a function of maintaining the ON state of the second switch90(a lock-on function). The second lock switch95is also referred to as a lock-on switch.

The controller5is configured to rotate the motor2when both of the first and second switches80,90are in the ON state. The controller5is configured to stop rotation of the motor2when at least one of the first and second switches80,90is in the OFF state.

As described above, a user can use the belt sander1of this embodiment in first and second use modes. The first use mode is a normal use mode in which the sanding surface B1is placed on a workpiece and a user performs a working operation while holding the handle14. In the second use mode, the belt sander1is set upside down, for example, on a stand or a desk, with the sanding surface B1facing vertically upward, and a user performs a working operation by pressing a workpiece onto the sanding belt B while holding the workpiece. The second lock switch95is mainly used in the second use mode.

<The Structure of the First Switch>

First, the structure of the first switch80is described. As shown inFIGS.12and13, the first switch80has a first switch operation part81and a first main switch82.

The first main switch82is held within the handle14of the body housing11. The first main switch82has a body821that is electrically connected to the controller5, and a plunger822that is exposed from a lower part of the body821and configured to be movable substantially in the up-down direction. The first main switch82is turned on (placed in an ON state) when the length of the exposed part of the plunger822is a prescribed threshold or less, and turned off (placed in an OFF state) when the length of the exposed part of the plunger822exceeds the prescribed threshold. The body821outputs an ON signal to the controller5when the first main switch82is ON.

The first switch operation part81is configured to be manually operated by a user. The first switch operation part81can be moved to a first ON position and a first OFF position. InFIG.13, the first switch operation part81placed in the first ON position is shown by solid lines, and the first switch operation part81placed in the first OFF position is shown by broken lines. The first ON position is a position of the first switch operation part81where the first switch operation part81acts on the first main switch82to place the first main switch82in the ON state. The first OFF position is a position of the first switch operation part81to place the first main switch82in the OFF state. The first switch operation part81is normally in the first OFF position. Operations of moving the first switch operation part81to the first ON position and the first OFF position are also referred to as an ON operation and an OFF operation, respectively. In this embodiment, the ON operation of the first switch operation part81is depressing it, and the OFF operation of the first switch operation part81is releasing the depressing operation.

The structure of the first switch operation part81is now specifically described. The first switch operation part81has a base811, a boss814and a projection815. The base811extends from front of the first main switch82to below the plunger822. Part of the base811protrudes downward from the opening144formed in the front lower part of the handle14. This protruding part has an external shape that conforms to user's fingers. The base811has an abutment part812(seeFIG.12) that abuts on a lower end of the plunger822. The projection815has a generally thick plate-like shape protruding upward from a front part of the base811. As shown inFIGS.14to16, the projection815is located substantially in the center of the handle14in the left-right direction, and the plane P1passes through the projection815(through this center). The boss814extends in the left-right direction in a front part of the base811and is supported by the handle14. The boss814is rotatable relative to the handle14.

When the ON operation of the first switch operation part81is not restricted by the first lock switch85, the first switch operation part81is depressed into the opening144by user's depressing operation. At this time, the first switch operation part81is turned clockwise around the boss814. Thus, the first switch operation part81is moved from a position shown by the broken lines to a position shown by the solid lines inFIG.13, and the projection815is moved forward. Further, the abutment part812pushes in the plunger822. When the abutment part812pushes in the plunger822, the first main switch82(the first switch80) is placed in the ON state. The first ON position is also a position of the first switch operation part81where the length of the exposed part of the plunger822is the prescribed threshold or less.

When the depressing operation of the first switch operation part81is released, the first switch operation part81is turned counterclockwise around the boss814and returned to an initial position, and the projection815is moved rearward. Further, the abutment part812releases pushing of the plunger822. Thus, the first switch80is placed in the OFF state. The first OFF position is also a position of the first switch operation part81where the length of the exposed part of the plunger822exceeds the prescribed threshold.

The first switch80further has a biasing member818configured to bias the first switch operation part81to the first OFF position. In this embodiment, a compression coil spring is used as the biasing member818. As shown inFIG.12, one end of the biasing member818is supported behind the boss814and in front of the abutment part812by the base811. The other end of the biasing member818is supported by an inner wall of the handle14. When the first switch operation part81is depressed against the biasing force of the biasing member818and placed in the first ON position, the first switch80is placed in the ON state. When the depressing operation of the first switch operation part81is released, the first operation part81is returned to the first OFF position by the biasing force of the biasing member818, and thus the first switch80is placed in the OFF state.

<The Structure of the First Lock Switch>

The structure of the first lock switch85is now described. The first lock switch85is configured to be moved between a lock-off position for restricting the ON operation of the first operation part81and a lock-off release position for allowing the ON operation of the first operation part81, by user's manual operation. The lock-off release position includes a lock-on position for maintaining the ON operation of the first switch80. The first lock switch85is normally placed in the lock-off position.FIGS.12and14show the first lock switch85placed in the lock-off position (the lock-off state), andFIGS.15and16show the first lock switch85placed in the lock-on position (in the lock-on state).

As shown inFIG.14, the first lock switch85has an operation stem851, a lock-off locking part853, lock-on locking parts855L,855R and a biasing member858. The first lock switch85is configured as a push-in operation part to be pushed in relative to the handle14by a user.

The operation stem851extends substantially in the left-right direction. In the lock-off state, as shown inFIG.14, a substantially central part of the operation stem851in the left-right direction is located on the plane P1. Left and right end parts of the operation stem851normally protrude from openings145L,145R formed in a left surface (a left wall14L) and a right surface (a right wall14R) of the handle14, respectively. The left and right end parts of the operation stem851serve as operation parts851L,851R, respectively. The first lock switch85is arranged within the reach of a hand of a user operating the first switch operation part81. Specifically, the operation part851R is arranged within the reach of the right thumb of a user holding the handle14with the right hand such that the user can depress the first switch operation part81with a right finger. Further, the operation part851L is arranged within the reach of the left thumb of a user holding the handle14with the left hand such that the user can depress the first switch operation part81with a left finger.

The lock-off locking part853is configured to abut on the projection815of the first switch operation part81and thus restrict a depressing operation of the first switch operation part81. In this embodiment, a recess854is formed in a central part of the operation stem851in the left-right direction and recessed rearward. The lock-off locking part853has a thick plate-like shape protruding forward and downward from a central front part of the recess854.

The lock-on locking parts855L,855R are respectively formed on left and right ends of the recess854and apart from the lock-off locking part853. The lock-on locking parts855L,855R are located behind the lock-off locking part853in the front-rear direction. The lock-on locking parts855L,855R each have a thick plate-like shape protruding downward. The distance between the lock-on locking part855L and the lock-off locking part853and the distance between the lock-on locking part855R and the lock-off locking part853in the left-right direction are each larger than the thickness of the projection815in the left-right direction. Therefore, the projection815(the first switch operation part81) is allowed to turn (into the lock-off release state) when disengaged from the lock-off locking part853. At this time, the first switch operation part81is allowed to turn until a rear wall (rear side) of the projection815reaches a position in front of front walls (front sides) of the lock-on locking parts855L,855R in the front-rear direction.

The operation stem851further has restriction walls854L,854R. The restriction walls854L,854R define the left and right ends of the recess854. The restriction wall854L is formed on the left front side of the lock-on locking part855L. The restriction wall854L abuts on the left surface of the projection815when the first lock switch85is pushed to the right. Thus, the restriction wall854L restricts rightward movement of the first lock switch85and positions the lock-on locking part855L directly behind the projection815. The restriction wall854R is formed on the right front side of the lock-on locking part855R The restriction wall854R abuts on the right surface of the projection815when the first lock switch85is pushed to the left. Thus, the restriction wall854R restricts leftward movement of the first lock switch85and positions the lock-on locking part855R directly behind the projection815.

The biasing member858is arranged behind the operation stem851so as to extend in the left-right direction. The biasing member858is configured to bias the first lock switch85to the lock-off position. In this embodiment, a compression coil spring is used as the biasing member858.

In this embodiment, a holding part859is integrally formed with the operation stem851on the rear of the operation stem851so as to hold the biasing member858. Left and right walls of the holding part859hold left and right ends of the biasing member858, respectively. The left and right walls of the holding part859each have an opening. Projections149L,149R protruding from left and right walls of the handle14abut on the left and right ends of the biasing member858through the openings of the holding part859, respectively. When the operation stem851is moved to the left, as shown inFIG.15, the biasing member858moves to the left together with the holding part859. At this time, the biasing member858is contracted with the right end of the biasing member858being supported by the right wall of the holding part859and with the left end of the biasing member858being supported by the projection149L. When the operation stem851is moved to the right, as shown inFIG.16, the biasing member858moves to the right together with the holding part859. At this time, the biasing member858is contracted with the left end of the biasing member858being supported by the left wall of the holding part859and with the right end of the biasing member858being supported by the projection149R.

As described above, the first lock switch85is normally placed in the lock-off position. As shown inFIG.14, the lock-off position is a position of the first lock switch85where the lock-off locking part853is located directly behind the projection815. In the lock-off position, the lock-off locking part853is located on the plane P1. The first lock switch85can be moved to a first lock-on position shown inFIG.15when pushed to the right by user's manual operation. The first lock-on position is a position of the first lock switch85where the lock-on locking part855R is located directly behind the projection815. In the first lock-on position, the lock-on locking part855R is located on the plane P1. Further, the first lock switch85can be moved to a second lock-on position shown inFIG.16when pushed to the left by user's manual operation. The second lock-on position is a position of the first lock switch85where the lock-on locking part855L is located directly behind the projection815. In the second lock-on position, the lock-on locking part855is located on the plane P1.

<Method of Operating the First Switch and the First Lock Switch>

As shown inFIGS.12and14, when the first lock switch85is located in the lock-off position, a rear wall of the lock-off locking part853abuts on (engages or interferes with) a front wall of the projection815of the first switch operation part81. Thus, the lock-off locking part853restricts forward movement of the projection815or the depressing operation of the first switch operation part81(in the lock-off state).

When the user pushes the operation part851R into the handle14, the first lock switch85is moved to the left from the lock-off position. Thus, the lock-off locking part853is disengaged from the projection815of the first switch operation part81(in the lock-off release state). Therefore, the projection815is allowed to turn clockwise, so that the depressing operation (ON operation) of the first switch operation part81is allowed. Further, when the user depresses the first switch operation part81, the projection815can be turned clockwise to be moved forward of the lock-on locking part855R in the front-rear direction.

When the user further pushes the first lock switch85to the left, as shown inFIG.15, the first lock switch85moves to the left until the restriction wall854R abuts on the right surface of the projection815. The lock-on locking part855R, which is formed on the left rear side of the restriction wall854R, is located directly behind the projection815when the restriction wall854R abuts on the right surface of the projection815. Thus, the first lock switch85is placed in the first lock-on position.

When the user releases the depressing operation (ON operation) of the first switch operation part81, the biasing member818(seeFIG.12) applies a biasing force to the first switch operation part81toward the first OFF position. At this time, however, the rear wall (rear side) of the projection815is engaged with the front wall (front side) of the lock-on locking part855R and restricts movement of the first switch operation part81to the first OFF position. Thus, the first switch operation part81is kept in the first ON position. Therefore, the ON operation of the first switch operation part81is maintained (in the lock-on state) even if the user releases the depressing operation of the first switch operation part81. At this time, the biasing member858of the first lock switch85is contracted as shown inFIG.15and biases the first lock switch85to the lock-off position. The biasing member818of the first switch80however biases the projection815of the first switch operation part81(the first switch operation part81) toward the first OFF position (in a direction to turn the projection815counterclockwise). Therefore, the biasing force of the biasing member818is applied to the lock-on locking part855R via the projection815so that the lock-on locking part855R is kept engaged with the projection815. Thus, the first lock switch85is kept in the first lock-on position.

In the state as shown inFIG.15where the first lock switch85is placed in the first lock-on position and the ON operation of the first switch operation part81is maintained, the projection815turns clockwise when the user further depresses the first switch operation part81. The projection815is then separated and disengaged from the lock-on locking part855R. Therefore, the first lock switch85is returned to the lock-off position by the biasing force of the biasing member858(seeFIG.14). Further, the first switch operation part81is returned to the first OFF position by the biasing force of the biasing member818.

The user can also move the first lock switch85from the lock-off position to the second lock-on position in the same manner as described above. Specifically, when the user pushes the operation part851L into the handle14, the first lock switch85is moved to the right from the lock-off position. Thus, the lock-off locking part853is disengaged from the projection815of the first switch operation part81. Further, when the user depresses (turns on) the first switch operation part81, the projection815can be moved forward of the lock-on locking part855L in the front-rear direction.

When the user further pushes the first lock switch85to the right, as shown inFIG.16, the first lock switch85moves to the right until the restriction wall854L abuts on the left surface of the projection815. The lock-on locking part855L, which is formed on the right rear side of the restriction wall854L, is located directly behind the projection815when the restriction wall854L abuts on the left surface of the projection815. Thus, the first lock switch85is placed in the second lock-on position.

When the user releases the depressing operation (ON operation) of the first lock switch85, the biasing member818applies a biasing force to the first switch operation part81toward the first OFF position. At this time, however, the rear wall of the projection815abuts on the front wall of the lock-on locking part855L and restricts movement of the first switch operation part81to the first OFF position. Thus, the first switch operation part81is kept in the first ON position. Therefore, the ON operation of the first switch operation part81(the lock-on state of the first switch80) is maintained (in the lock-on state of the first switch80) even if the user releases the depressing operation of the first lock switch85. At this time, the biasing force of the biasing member818is applied to the lock-on locking part855L (the first lock switch85) via the projection815, so that the first lock switch85is kept in the second lock-on position.

In the state as shown inFIG.16where the first lock switch85is placed in the second lock-on position and the ON operation of the first switch operation part81is maintained, the projection815turns clockwise when the user further depresses the first switch operation part81. Thus, the projection815is disengaged from the lock-on locking part855R. Therefore, the first lock switch85is returned to the lock-off position by the biasing force of the biasing member858(seeFIG.14). Further, the first switch operation part81is returned to the first OFF position by the biasing force of the biasing member818.

As described above, when the first switch80is in the lock-on state (seeFIGS.15and16), the user can place the first switch80in the OFF state and also place the first switch80in the lock-off state simply by depressing the first switch operation part81once and then releasing the depressing operation.

<The Structure of the Second Switch>

The structure of the second switch90is now described. As shown inFIG.12, the second switch90has a second switch operation part91and a second main switch92.

The second main switch92is held behind the first switch80within the handle14of the body housing11. The second main switch92has a body921that is electrically connected to the controller5, and an actuator922that protrudes upward from an upper part of the body921. The actuator922is pushed into the body921when pressed downward. The second main switch92is turned on (placed in the ON state) when the amount of pushing (pressing) the actuator922into the body921is a prescribed threshold or more, and turned off (placed in the OFF state) when the amount of pushing (pressing) the actuator922into the body921is less than the prescribed threshold. The body921outputs an ON signal to the controller5when the second main switch92is ON.

The second switch operation part91is arranged behind the first switch operation part81and the first lock switch85. The second switch operation part91is arranged below an imaginary plane P2(seeFIG.6) including the upper wall121of the first part12(the motor housing part). As shown inFIG.12, the second switch operation part91is arranged in the handle14such that part of the second switch operation part91protrudes upward from the opening149formed in the rear upper part of the handle14, and is movable substantially in the up-down direction. The second switch operation part91is configured to be manually operated by a user. The second switch operation part91can be moved to a second ON position and a second OFF position. InFIG.17, the second switch operation part91placed in the second ON position is shown by solid lines, and the second switch operation part91placed in the second OFF position is shown by broken lines. The second ON position is a position of the second switch operation part91where the second switch operation part91acts on the second main switch92to drive the motor2. The second OFF position is a position of the second switch operation part91to stop driving of the motor2. The second switch operation part91is normally in the second OFF position. Operations of moving the second switch operation part91to the second ON position and the second OFF position are also referred to as an ON operation and an OFF operation, respectively. In this embodiment, the ON operation of the second switch operation part91is pushing it, and the OFF operation of the second switch operation part91is releasing the pushing operation.

The structure of the second switch operation part91is now specifically described. The second switch operation part91has a base911, a pivot shaft (turning shaft)916extending in the left-right direction and having left and right ends supported by the handle14, and a biasing member918. The base911is arranged above and in front of the second main switch92and extends in the front-rear direction. The base911has a rear part projecting downward. An abutment part912is provided in a rear lower part of the base911and configured to abut on an upper end of the actuator922.

Part of the base911normally protrudes upward from the opening149formed in the rear upper part of the handle14(seeFIG.12). This protruding part has a dorsal fin-like shape. A shaft hole915is formed in a front end part of the base911and extends in the left-right direction, and the pivot shaft916is inserted through the shaft hole915. The base911is turnable around the pivot shaft916. The base911is turned counterclockwise (downward) and pushed into the opening149by user's pushing operation.

The base911is formed in a block shape having a space inside. As shown inFIG.12, an opening917is formed in a left wall911L of the base911. The position and size of the opening917are set such that a locking part954of the second lock switch95can be inserted into the inside space of the base911, which will be described below in detail.

The biasing member918is configured to bias the second switch operation part91to the second OFF position. In this embodiment, a torsion spring is used as the biasing member918. A coil part of the torsion spring918is fitted on the pivot shaft916. A support wall142is formed to extend rearward and downward from the front of the base911within the handle14, and one arm918fof the torsion spring918is fixed to the support wall142. The other arm (not shown) of the torsion spring918is fixed to the base911and biases the base911upward (in the clockwise direction).

The second switch operation part91is pushed into the opening149by user's pushing operation. At this time, the second switch operation part91is turned counterclockwise around the pivot shaft916. Thus, the abutment part912moves downward and pushes in the actuator922, so that the second main switch92(the second switch90) is placed in the ON state. This second ON position is also a position of the second switch operation part91where the amount of pushing (pressing) the actuator922is a prescribed threshold or more.

When the pushing operation of the second switch operation part91is released, the second switch operation part91is turned clockwise around the pivot shaft916and returned to an initial position, so that the abutment part912releases pushing of the actuator922. Thus, the second switch90is placed in the OFF state. The second OFF position is also a position of the second switch operation part91where the amount of pushing (pressing) the actuator922is less than the prescribed threshold.

<The Structure of the Second Lock Switch>

The second lock switch95is provided in a rear part of the handle14and configured to act on the second switch90. The second lock switch95is arranged behind the first lock switch85in the front-rear direction and below the first lock switch85in the up-down direction. As shown inFIG.18, part of the second lock switch95is exposed from an opening147formed in the left wall14L of the handle14. The second lock switch95is normally placed in the OFF position (non-lock-on position) (seeFIG.18). The second lock switch95can be moved to a lock-on position for maintaining the ON operation of the second switch operation part91by user's manual operation (seeFIG.19).

A recess146is formed in a position corresponding to a rear part of the second switch operation part91, in the left wall14L of the handle14and recessed rightward as shown inFIGS.18and19. The second lock switch95is arranged in the recess146. The recess146has a multi-stepped circular shape having an inner diameter decreasing step by step to the right. The opening147is arranged substantially in the central part of the recess146. The recess146has a first flange146aand a second flange146bthat are orthogonal to the left-right direction. The second flange146bis an annular wall formed around the opening147. The first flange146ais an annular wall formed on the left side of the second flange146band around the second flange146b.

The second lock switch95has a stepped pin953, an operation part951provided on a left end part of the stepped pin953, and a biasing member958.

The stepped pin953extends substantially in the left-right direction and is movable in the left-right direction. The stepped pin953is arranged in the handle14so as to be inserted into the opening917of the base911when the second switch operation part91is pushed. The stepped pin953is inserted through the opening147while a right end part of the stepped pin953is arranged within the handle14and a left end part of the stepped pin953is arranged within the recess146(on the left side of the opening147). The outer diameter of the right end part of the stepped pin953is larger than the diameter of the opening147, so that the stepped pin953is prevented from coming off from the handle14. Further, the right end part of the stepped pin953serves as a locking part954that is configured to be locked to the second switch operation part91to keep the second switch operation part91in the second ON position, which will be described below in detail.

The operation part951has a cap-like shape to be fitted onto the left end part of the stepped pin953. The operation part951can be moved in the left-right direction together with the stepped pin953. The outer diameter of the operation part951is larger than that of the second flange146band smaller than that of the first flange146a,so that the first flange146arestricts rightward movement of the operation part951. Unlike the first lock switch85, the operation part951of the second lock switch95does not protrude leftward from the left wall14L surrounding the recess146in the left-right direction.

The biasing member958is configured to bias the second lock first switch95to the non-lock-on position. In this embodiment, a compression coil spring is used as the biasing member958. The biasing member958is fitted onto the stepped pin953. A left end of the biasing member958is supported by a flange part952of the operation part951and a right end of the biasing member958is supported by the second flange146b.

<Method of Operating the Second Switch and the Second Lock Switch>

As shown inFIGS.12and18, part of the second switch operation part91(the base911) protrudes upward from the handle14through the opening149formed in the handle14(in the second OFF position). As described above, the second switch operation part91is pushed into the opening149and moved to the second ON position by user's pushing operation, so that the second main switch92(the second switch90) is placed in the ON state.

When the user pushes the operation part951of the second lock switch95into the handle14while pushing the second switch operation part91, the locking part954of the second lock switch95is inserted into the inside space of the base911from the opening917formed in the base911of the second switch operation part91. When the pushing operation of the second switch operation part91is released, the second switch operation part91is returned to the initial position (the second OFF position) by the biasing force of the torsion spring918. Before the second switch operation part91is disengaged (moved) from the second ON position, however, the locking part954of the stepped pin953is engaged with the left wall911L surrounding the opening917in the base911(seeFIG.19). Thus, the second switch operation part91is kept in the second ON position (in the lock-on state). Further, the second lock switch95is biased to the non-lock-on position by the biasing member958, but kept in the lock-on position by engagement between the locking part954and the base911. In this manner, the ON state of the second switch90is maintained even if the user releases the fingers from the second switch operation part91and the second lock switch95.

In the above-described lock-on state, when the user pushes the second switch operation part91, the second switch operation part91is turned counterclockwise (downward), so that the locking part954of the stepped pin953is disengaged from the left wall911L of the base911. Thus, the second lock switch95is returned to the non-lock-off position by the biasing force of the biasing member958(seeFIG.18). Further, the second switch operation part91is returned to the second OFF position by the biasing force of the biasing member918. Thus, in the lock-on state, the user can place the second switch90in the OFF state simply by pushing the second switch operation part91once and then releasing the pushing operation.

The above-described switching mechanism8can be operated in the first and second use modes as follows. In the first use mode, the user pushes the second switch operation part91, for example, with the left hand. Then, the user can release the lock-off state of the first switch80by pushing in the operation part851R of the first lock switch85with the right thumb while putting the right hand on the first switch operation part81. Further, the user can maintain the ON state of the first switch80(in the lock-on state) by depressing the first switch operation part81with the right hand and further pushing in the operation part851R of the first lock switch85with the right thumb. In order to place the first switch80in the lock-on state, the user may also push the second switch operation part91with the right hand and push in the operation part851L of the first lock switch85with the left thumb while putting the left hand on the first switch operation part81. In this state, when the user releases the hand from the belt sander1, the second switch operation part91is returned to the second OFF position and the second switch90is placed in the OFF state. Therefore, the user can stop the belt sander1simply by releasing the pushing operation of the second switch operation part91.

In the second use mode, the user places the second switch90in the lock-on state by pushing the second switch operation part91(into the second ON position) and pushing in the second lock switch95. Further, the user can place the first switch80in the lock-on state by operating the first switch operation part81and the first lock switch85in the same manner as in the first use mode. In this manner, the user can perform a working operation while releasing the hands from the belt sander1and holding a workpiece. As described above, the user can place the second switch90in the OFF state to stop the belt sander1simply by pushing the second switch operation part91once and then releasing the pushing operation.

As described above, in the belt sander1of this embodiment, the ON state of the first switch80can be maintained with the first lock switch85and the ON state of the second switch90can be maintained with the second lock switch95. Therefore, in the second use mode, the belt sander1of this embodiment can stably continue to drive the motor2even if placed on a slightly uneven surface.

Further, in the lock-off state, the operation parts851L,851R of the second lock switch85protrude from the left and right walls14L,14R of the handle14, respectively, and the operation part951of the second lock switch95is arranged in the recess146formed in the left wall14L of the handle14. This configuration facilitates continuous operations of the first and second lock switches85,95in the second use mode. Therefore, in the second use mode, the maneuverability in driving the belt sander1is improved.

Further, in the belt sander1, a part (the first part12) of the housing10in which the motor2is housed has the upper wall121that is substantially parallel to the sanding belt B, and the second switch operation part91is arranged below the imaginary plane P2including the upper wall121. Thus, in the second use mode, the attitude of the belt sander1is stabilized by the upper wall121being placed on a desk or a stand.

The first lock switch85is configured to have a function (lock-off function) of preventing the first switch80from being placed in the ON state, as well as a function (lock-on function) of maintaining the ON state of the first switch80. This can suppress complication of the switching mechanism and an increase in the size of the belt sander which may be caused by separately providing a switch having a lock-off function. Thus, according to this embodiment, the maneuverability in driving the belt sander1is improved, and the belt sander1can be more compact.

The second switch operation part91protrudes from the upper surface of the handle14, so that the user can push in the second switch operation part91from above to place the second switch90in the ON state. Thus, in the first use mode, the maneuverability in driving the belt sander1is also improved.

Further, the second switch operation part91is returned to the second OFF position when the user releases the pushing operation of the second switch operation part91. Thus, in the first use mode, the belt sander1is prevented from moving by itself even if the user releases the hand from the belt sander1.

The second lock switch95is moved in the left-right direction crossing the moving direction (substantially the up-down direction) of the second switch operation part91. Therefore, the second lock switch95is avoided from being unintentionally operated by being carelessly touched with the user' s hand. In this embodiment, the second lock switch95is configured not to protrude outward from the handle14(to the left from the left wall14L). Thus, the second lock switch95is further avoided from being unintentionally operated.

(Other Embodiments of the Switching Mechanism>

The first and second switches80,90may have configurations other than those described above only if each configured as a momentary switch. For example, the first switch operation part81and the second switch operation part91may be each configured as a sliding operation part that is moved to the first or second ON position and the first or second OFF position by user's sliding operation. Likewise, the first lock switch85and the second lock switch95may have configurations other than those described above only if configured to maintain their respective ON operations of the first and second switches80,90.

In the above-described embodiment, a compression coil spring is used as the biasing members818,858,958, and a torsion spring is used as the biasing member918, but other biasing members (elastic bodies) may be used as the biasing members818,858,918,958.

In the above-described embodiment, the second lock switch95is provided on the left wall14L of the handle14, but it may be provided on the right wall14R of the handle14or on the left and right walls14L,14R.

<The Structure of the Battery Mounting Part>

The structure of the battery mounting part4is now described with reference toFIGS.1to5and20. The battery mounting part4is provided above the belt driving part6(on the second part13of the body housing11). The battery mounting part4is configured such that a rechargeable battery300having a well-known structure can be mounted and removed to and from the battery mounting part4by being slid in a sliding direction relative to the battery mounting part4.

One example of the battery that can be removably mounted to the battery mounting part4is first described. The battery300shown inFIG.20is an example of a battery pack to be mounted to the battery mounting part4. InFIG.20, the battery300has a case310for housing a plurality of battery cells, and a mounting part320configured to be removably mounted to the battery mounting part4. The mounting part320has a mounting face321that faces a mounting face41of the battery mounting part4when the battery300is mounted to the battery mounting part4. As for the directions of the battery300shown inFIG.20, the side of the case310on which the mounting face32is provided is defined as a lower side and the opposite side is defined as an upper side. A direction crossing the up-down direction and corresponding to the sliding direction of the battery300is defined as a front-rear direction, and in the front-rear direction, the side on which a locking member305(described below) is provided is defined as a front side and the opposite side is defined as a rear side. Further, a direction crossing the up-down direction and the front-rear direction is defined as a left-right direction.

The mounting part320has the mounting face321, a pair of rail receiving parts322, a pair of power terminals324and a signal terminal326. The mounting face321faces the mounting face41(described below in detail) of the battery mounting part4when the battery300is mounted to the battery mounting part4of the belt sander1. In this embodiment, the mounting face321is a lower surface of the case310and includes a lower surface of a part (a protruding part311) of a front lower part of the case310that protrudes downward. The mounting face321is substantially parallel to the front-rear direction and the left-right direction. The battery300has a rectangular box-like shape having a shorter length (width) in the up-down direction than the lengths (widths) in the front-rear direction and the left-right direction. The battery300(the case310) has a long side in the sliding direction. A surface (an upper surface312) of the battery300on the side opposite to the mounting face321has the largest area on the battery300. The rail receiving parts322are respectively provided on left and right surfaces of the protruding part311and extend in the long-side direction of the case310(the front-rear direction). The rail receiving parts322are configured to be engaged with a pair of guide rails42(seeFIG.5) of the battery mounting part4.

The mounting part320further has a locking member305provided in a front lower part of the protruding part311. The locking member305is engaged with a lock receiving part of the battery mounting part4to lock the battery300to the battery mounting part4. When an unlock button (not shown) is pushed by a user, the locking member305is disengaged or unlocked from the lock receiving part.

As shown inFIGS.2and5, the battery mounting part4is provided on the second part13of the body housing11. The battery mounting part4is formed inside the upper wall131and the side walls133and configured such that the battery300can be mounted thereto from the front. As described above, a part of the body housing11that is located above the belt driving part6has a stepped shape in which the upper wall131of the second part13is located below the upper wall121of the first part12. It can also be said that the battery mounting part4is provided in front of the motor2and above the belt driving part6since the first part12houses the motor2. Further, it can also be said that the battery mounting part4overlaps with the belt driving part6when viewed from above and overlaps with the motor2when viewed from the front.

As shown inFIG.6, the battery mounting part4is configured such that the battery300mounted to the battery mounting part4(this state is hereinafter referred to as a battery mounted state) does not protrude upward from the upper wall121of the housing10in the up-down direction. Further, the battery mounting part4is configured such that the battery300does not protrude forward from a front end of the body housing11in the front-rear direction in the battery mounted state. In this embodiment, as shown inFIG.6, the surface (the upper surface312) of the battery300on the side opposite to the mounting face321is located substantially in the same position as the upper wall121of the first part12of the body housing11in the up-down direction. Further, a front surface314of the battery300is located substantially in the same position as the front end of the body housing11in the front-rear direction. Further, as shown inFIG.4, the battery mounting part4is configured such that the battery300does not protrude leftward from a left end of the left body housing11L and rightward from a right end of the right body housing11R in the left-right direction. In other words, the battery mounting part4is configured such that the battery300is fitted within the width of the second part13of the boy housing11in the left-right direction in the battery mounted state. In this embodiment, a right surface313of the battery300is located substantially in the same position as the side walls123,133of the right body housing11R in the left-right direction.

The battery mounting part4has a mounting face41, a pair of guide rails42, a pair of power terminals44and a signal terminal46. In this embodiment, the battery300is slid in the front-rear direction relative to the battery mounting part4. Specifically, the battery300is mounted onto the battery mounting part4in a direction from the front to the rear, and the battery300is removed from the battery mounting part4in a direction from the rear to the front.

The mounting face41faces a surface (the mounting face321) of the battery300when the battery300is mounted to the battery mounting part4. The mounting face41is substantially parallel to the front-rear direction and the left-right direction. The guide rails42are respectively provided on the insides of the side walls133of the second part13and extend in the front-rear direction. The guide rails42are configured to be engaged with the rail receiving parts322of the battery300. The guide rails42guide the rail receiving parts322in the front-rear direction when the mounting part320of the battery300is mounted to the battery mounting part4. It can also be said that the mounting face41is substantially parallel to the sliding direction of the battery300.

The power terminals44are provided between the guide rails42. The power terminals44each have a plate-like shape protruding upward from the mounting face41and extending in the front-rear direction. The power terminals44are configured to receive power from the battery300mounted to the battery mounting part4. The signal terminal46is provided between the power terminals44, protrudes upward from the mounting face41and extends in the front-rear direction. The signal terminal46is configured to transmit and receive signals to and from the battery300mounted to the battery mounting part4.

When the mounting part320of the battery300is slid onto the battery mounting part4from the front, the rail receiving parts322of the battery300are engaged with the guide rails42of the battery mounting part4and the battery300is mounted to the battery mounting part4. At this time, the mounting face41of the battery mounting part4faces the mounting face321of the battery300. Further, the power terminals44of the battery mounting part4are electrically connected to the power terminals324of the battery300, respectively, and the signal terminal46of the battery mounting part4is electrically connected to the signal terminal326of the battery300.

The battery mounting part4further includes a lock receiving hole47that is engaged with the locking member305of the battery300. When the battery300is mounted to the battery mounting part4, the locking member305is engaged with the lock receiving hole47, and the battery300is locked to be immovable in the front-rear direction. When the unlock button of the battery300is pushed down in this locked state, the locking member305is disengaged or unlocked from the lock receiving hole47. In the disengaged state, the battery300is removed from the battery mounting part4when slid forward relative to the battery mounting part4.

The belt sander1of this embodiment further has a front handle17. The front handle17is connected to the housing10so as to be turnable relative to the housing10. As shown inFIG.3, a pivot axis A4of the front handle17extends in the left-right direction. The front handle17is also referred to as a “second handle”.

The front handle17turns around the pivot axis A4extending in the left-right direction. The front handle17has an arm171having a proximal end part172and a distal end part173and extending in a direction crossing the pivot axis A4, and a grip part175configured to be held by a user.

As shown inFIGS.4and5, the proximal end part172of the arm171is removably mounted to a turning part18provided on a left wall (the fan housing161) of the housing10. The turning part18is configured to be engaged with the proximal end part172of the arm171so as to allow the arm171to turn within a prescribed range around the pivot axis A4. The grip part175extends rightward from the distal end part173of the arm171. The grip part175is parallel to the left-right direction. A distal end (right end) of the grip part175is located on the left side of a right end (the right walls123,133) of the housing10. The length of the grip part175in the left-right direction is set such that the grip part175is fitted within the width of the housing10in the left-right direction. The length of the arm171of the front handle17and the position of the proximal end part172of the arm171on the housing10are adjusted to prevent the grip part175from coming into contact with the housing10and the battery300mounted to the battery mounting part4when the front handle17is turned.

A plurality of radially extending cam faces are formed on the turning part18and a part (a right surface of the proximal end part172of the grip part175) of the front handle17that faces the turning part18. The front handle17is configured to be positioned at a plurality of turning positions by engagement between the cam faces of the front handle17and the cam faces of the turning part18. In this embodiment, the front handle17can be positioned at four turning positions (angular positions). As shown inFIG.3, by turning of the arm171around the pivot axis A4, the front handle17(the grip part175) is moved to positions R1, R2, R3and R4in order from the lower position to the upper position. The grip part175is fixedly positioned in the position R1, R2, R3or R4by engagement between the proximal end part172of the arm171and the turning part18.

In the position R1, the grip part175is located in front of the front end of the housing10(the second part13) and below the mounting face41. In the position R2, the grip part175is located in front of the front end of the housing10and directly in front of the battery300mounted to the battery mounting part4. In this embodiment, in the position R2, as shown inFIG.6, an upper end of the grip part175is located substantially in the same position in the up-down direction as an upper end part of the housing10(the upper wall121of the first part12) and the upper surface312of the battery300mounted to the battery mounting part4. In the position R2, the plane P2including the upper wall121passes the upper end of the grip part175and the upper surface312of the battery300. The position R2is also referred to as a “first turning position”.

In the positions R3and R4, the grip part175is located behind the front end of the housing10and above the upper wall121of the housing10in the up-down direction. The position R3is a position suitable for a user to perform a working operation in the first use mode while holding the handle14with one hand and holding the front handle17with the other hand. The position R4is a position suitable for a user to carry the belt sander1(while holding the handle14with one hand and holding the front handle17with the other hand). In the position R1, the grip part175is located below the mounting face41, and in the positions R3and R4, the grip part175is located above the upper end part of the housing10(the upper wall121of the first part12), that is, above the battery300mounted to the battery mounting part4. Thus, the user can turn the front handle17to move the grip part175to the position R1, R3or R4and mount and remove the battery300to and from the battery mounting part4. The positions R1, R3and R4are also each referred to as a “second turning position”.

Effects of the belt sander1having the battery mounting part4of this embodiment are now described. The battery mounting part4of this embodiment is arranged in a position to overlap with the belt driving part6(the sanding belt B, the sanding surface B1) when viewed from above and to overlap with the motor2when viewed from the front. Therefore, the weights of the motor2and the battery300mounted to the battery mounting part4are applied to the sanding surface B1during driving of the belt sander1. Thus, the working operation can be performed by utilizing the masses of the motor2and the battery300, so that the operational efficiency of the belt sander1is improved.

Further, the battery mounting part4is configured such that the upper surface312of the battery300is located substantially in the same position as the upper wall121of the first part12of the body housing11in the up-down direction in the battery mounted state. Further, the right surface313of the battery300is located substantially in the same position as the side walls123,133of the right body housing11R in the left-right direction. Furthermore, the front surface314of the battery300is located substantially in the same position as the front end of the body housing11in the front-rear direction. With this configuration, the belt sander1can be more compact in the up-down direction, the left-right direction and the front-rear direction in the battery mounted state, and the possibility that the working range of the belt sander1is restricted by contact of the battery300with a structure such as a wall located in front or on the right or left of the belt sander1is reduced.

Further, when the user uses the belt sander1in the mode (the second use mode) in which the belt sander1is set upside down with the sanding surface B1facing vertically upward and a user performs a working operation by pressing a workpiece onto the sanding belt B while holding the workpiece, the upper wall121of the housing10and the upper surface312of the battery300are placed in contact with a desk or the like since the upper surface312of the battery300is located substantially in the same position as the upper wall121of the housing10in the up-down direction in the battery mounted state. Therefore, the attitude of the belt sander1in the second use mode is stabilized. Further, the upper surface312of the battery300has the largest area on the battery300, so that the contact area with the desk or the like is relatively large. Thus, the attitude of the belt sander1in the second use mode is more stabilized.

The battery300is mounted to the battery mounting part4of the belt sander1along the extending direction of the handle14in a direction from the front to the rear. Therefore, for example, when mounting the battery300to the battery mounting part4, the user can easily apply a force in a direction (from the rear to the front) opposite to the mounting direction of the battery300with the hand holding the handle14. Thus, the belt sander1of this embodiment provides the advantage that the battery300can be easily mounted to the battery mounting part4.

Further, the belt sander1has the front handle17that is turnable relative to the housing10. By turning the front handle17, the grip part175is moved to the position R1(the second turning position) in which the grip part175is located below the battery300mounted to the battery mounting part4in the up-down direction, the position R2(the first turning position) in which the upper end of the grip part175is located substantially in the same position as the upper wall121of the housing10, and the positions R3and R4(the second turning position) in which the grip part175is located above the battery300mounted to the battery mounting part4. Therefore, when the front handle17is turned such that the grip part175is moved to the position R2and the belt sander1is used in the second use mode, the upper wall21of the housing10, the grip part175and the upper surface312of the battery300mounted to the battery mounting part4are placed in contact with a desk or the like on which the belt sander1is placed. Thus, the attitude of the belt sander1in the second use mode is further stabilized. Further, the battery300can be mounted to and removed from the battery mounting part4by turning the front handle17to move the grip part175to the position R1, R3or R4.

Further, in view of the nature of the present disclosure and the above-described embodiment, the following aspects can be provided. At least one of the following aspects can be adopted in combination with at least one of the above-described embodiment, its modifications and the claimed invention.

(Aspect 1-1) A belt sander, comprising:an electric motor;a housing that includes a motor housing part for housing the motor;a belt driving part that includes a drive roller configured to be rotated by the motor, and a driven roller, and is configured to drive an endless sanding belt looped over the drive roller and the driven roller, wherein:where a direction in which a rotational axis of the drive roller and a rotational axis of the driven roller extend is defined as a left-right direction, a direction in which the drive roller and the driven roller are arranged in parallel is defined as a front-rear direction, and a direction orthogonal to the left-right direction and the front-rear direction is defined as an up-down direction, the belt driving part is arranged below the motor, and a polishing surface is defined by a lower surface of the sanding belt;a first handle that is provided on one side or rear side of the motor in the front-rear direction to extend in the front-rear direction and configured to be held by a user; anda battery mounting part configured such that a battery as a power source of the motor can be mounted thereto and removed therefrom by being slid in a sliding direction,wherein:the battery mounting part is arranged in a position to overlap with the polishing surface when viewed from above and to overlap with the motor when viewed from the front, andthe sliding direction is a horizontal direction including the front-rear direction and the left-right direction.

(Aspect 1-2) The motor housing part has an upper wall substantially parallel to the polishing surface, andthe battery mounting part is provided below the upper wall in the up-down direction.

(Aspect 1-3) The battery mounting part is configured such that the battery mounted to the battery mounting part does not protrude upward from the upper wall in the up-down direction.

(Aspect 1-4) The battery mounting part is configured such that the battery mounted to the battery mounting part protrudes upward from the upper wall by a prescribed protruding length in the up-down direction, andthe protruding length is 10% or less of a length of the battery in the up-down direction.

(Aspect 1-5) The battery mounting part is configured such that the battery mounted to the battery mounting part does not protrude from a front end of the housing in the front-rear direction.

(Aspect 1-6) The battery mounting part is configured such that the battery mounted to the battery mounting part protrude forward from a front end of the housing by a prescribed protruding length in the front-rear direction, andthe protruding length is 10% or less of a length of the battery in the front-rear direction.

(Aspect 1-7) The battery mounting part is configured such that the battery mounted to the battery mounting part does not protrude from left and right ends of the housing in the left-right direction.

(Aspect 1-8) The battery mounting part is configured such that the battery mounted to the battery mounting part protrudes leftward or rightward from the left or right end of the housing by a prescribed protruding length in the left-right direction, andthe protruding length is 10% or less of a length of the battery in the left-right direction.

(Aspect 1-9) The sliding direction is the front-rear direction, andthe battery mounting part is configured such that the battery can be mounted to the battery mounting part by being slid in a direction from the front to the rear relative to the battery mounting part.

(Aspect 1-10) The battery mounting part is configured such that the battery can be mounted thereto and removed therefrom by being slid in the left-right direction.

(Aspect 1-11) The belt sander includes a second handle, the second handle having an arm having a pivot axis extending in the left-right direction and connected to the housing, and a grip part connected to the arm and configured to be held by a user, the second handle being turnable relative to the housing, andaccording to a turning operation of the second handle, the grip part moves to:a first turning position in which an upper end of the grip part is located substantially in the same position as an upper wall of the motor housing part in the up-down direction, anda second turning position in which the grip part is located below or above the battery mounted to the battery mounting part, in the up-down direction.

(Aspect 1-12) A belt sander, comprising:an electric motor;a housing that includes a motor housing part for housing the motor;a belt driving part that includes a drive roller configured to be rotated by the motor, and a driven roller, and is configured to drive an endless sanding belt looped over the drive roller and the driven roller, wherein:where a direction in which a rotational axis of the drive roller and a rotational axis of the driven roller extend is defined as a left-right direction, a direction in which the drive roller and the driven roller are arranged in parallel is defined as a front-rear direction, and a direction orthogonal to the left-right direction and the front-rear direction is defined as an up-down direction, the belt driving part is arranged below the motor, and a polishing surface is defined by a lower surface of the sanding belt;a first handle that is provided on one side or rear side of the motor in the front-rear direction to extend in the front-rear direction and configured to be held by a user;a second handle that has an arm having a pivot axis extending in the left-right direction and connected to the housing, and a grip part connected to the arm and configured to be held by a user, the second handle being turnable relative to the housing; anda battery mounting part configured such that a battery as a power source of the motor can be mounted thereto and removed therefrom by being slid in a sliding direction,wherein:the battery mounting part is arranged in a position to overlap with the polishing surface when viewed from above and to overlap with the motor when viewed from the front,the battery mounting part is configured such that the battery mounted to the battery mounting part does not protrude from an upper wall of the motor housing part in the up-down direction,according to turning (turning operation) of the second handle, the grip part moves to:a first turning position in which an upper end of the grip part is located substantially in the same position as the upper wall in the up-down direction, anda second turning position in which the grip part is located below or above the battery mounted to the battery mounting part, in the up-down direction.

(Aspect 1-13) The battery mounting part is configured such that an upper surface of the battery mounted to the battery mounting part is located substantially in the same position as the upper wall in the up-down direction.

(Aspect 1-14) A belt sander, comprising:an electric motor;a housing that includes a motor housing part for housing the motor;a belt driving part that includes a drive roller configured to be rotated by the motor, and a driven roller, and is configured to drive an endless sanding belt looped over the drive roller and the driven roller, wherein:where a direction in which a rotational axis of the drive roller and a rotational axis of the driven roller extend is defined as a left-right direction, a direction in which the drive roller and the driven roller are arranged in parallel is defined as a front-rear direction, and a direction orthogonal to the left-right direction and the front-rear direction is defined as an up-down direction, the belt driving part is arranged below the motor, and a polishing surface is defined by a lower surface of the sanding belt;a first handle that is provided on one side or rear side of the motor in the front-rear direction to extend in the front-rear direction and configured to be held by a user; anda battery mounting part configured such that a battery as a power source of the motor can be mounted thereto and removed therefrom by being slid in a sliding direction,wherein:the battery mounting part is arranged on an upper wall of the motor housing part to overlap with the motor and the polishing surface when viewed from above, andthe battery mounting part is configured such that the battery can be mounted thereto by being slid in a direction from the rear to the front relative to the battery mounting part.

(Aspect 1-15) The belt sander to which the battery is removably mounted.

(Aspect 2-1) A belt sander, comprising:an electric motor;a housing that houses the motor;a belt driving part that includes a drive roller configured to be rotated by the motor, and a driven roller, and is configured to drive an endless sanding belt looped over the drive roller and the driven roller, wherein:where a direction in which a rotational axis of the drive roller and a rotational axis of the driven roller extend is defined as a left-right direction, a direction in which the drive roller and the driven roller are arranged in parallel is defined as a front-rear direction, and a direction orthogonal to the left-right direction and the front-rear direction is defined as an up-down direction, the belt driving part is arranged below the motor, and a polishing surface is defined by a lower surface of the sanding belt;a first switch that is arranged in the housing and has a first switch operation part, the first switch operation part being configured to be manually operated by a user to be moved to a first ON position to place the first switch in an ON state and a first OFF position to place the first switch in an OFF state; anda second switch that is arranged in the housing and has a second switch operation part, the second switch operation part being configured to be manually operated by a user to be moved to a second ON position to place the second switch in an ON state and a second OFF position to place the second switch in an OFF state;wherein:the first and second switches are each a momentary switch,the motor is configured to be driven when the first and second switches are in the ON state, and to be stopped when at least one of the first and second switches is in the OFF state,the belt sander further comprising:a first lock switch that is arranged in the housing and configured to keep the first switch operation part in the first ON position; anda second lock switch that is arranged in the housing and configured to keep the second switch operation part in the second ON position.

(Aspect 2-2) The housing includes a motor housing part for housing the motor, and a grip part that is connected to the motor housing part and extends rearward from the motor housing part,the second switch operation part is provided in the grip part and shaped to protrude upward from the grip part in the second OFF position, andthe second switch operation part is configured to be moved from the second OFF position to the second ON position when pushed relative to the grip part.

(Aspect 2-3) The second lock switch is provided in the housing so as to be movable in a direction crossing a moving direction of the second switch operation part.

(Aspect 2-4) The first and second lock switches are provided on the same side of the housing.

(Aspect 2-5) The second lock switch is provided below the first lock switch.

(Aspect 2-6) The first lock switch is configured to be moved to:a lock-off position to be engaged with the first switch operation part placed in the first OFF position to restrict movement of the first switch operation part to the first ON position, anda lock-on position to be engaged with the first switch operation part placed in the first ON position to restrict movement of the first switch operation part to the first OFF position.

(Aspect 2-7) The first switch has a first biasing member that biases the first switch operation part placed in the first ON position to be returned to the first OFF position, andthe second switch has a second biasing member that biases the second switch operation part placed in the second ON position to be returned to the second OFF position.

(Aspect 2-8) The grip part extends rearward and downward from the motor housing part,the first switch operation part is provided in the grip part between the second switch and the motor housing part and shaped to protrude downward from the grip part in the first OFF position, andthe first switch operation part is configured to be moved from the first OFF position to the first ON position when depressed relative to the grip part.

(Aspect 2-9) An upper wall of the motor housing part is substantially parallel to the polishing surface, andthe second switch operation part is provided below an imaginary plane including the upper wall.

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