Portable cutter for metal working and portable cutter

Abstract

To provide a portable cutter with a dust box excellent in workability which is attached to / detached from the cutter body.SOLUTION: A portable cutter 1 for metal working comprises: a cutter body 10; and a dust box 20 which is attached to / detached from the cutter body 10. A blade tool 4 is rotatably attached to the cutter body 10. The dust box 20 includes: a first housing 21; a second housing 22; and an inner plate 25. The first housing 21 made of synthetic resin includes a first lateral face 21a positioned inside of the cutter body 10. The second housing 22 made of synthetic resin includes a second lateral face 22a positioned at an opposite side of the first lateral face 21a and is connected with the first housing 21 to each other. The inner plate 25 is arranged through the second lateral face 22a and an air space layer A.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a portable cutting machine for metalwork used for cutting metal materials such as iron, and a portable cutting machine used for cutting iron, siding boards, gypsum boards, wood, etc. [Background technology]

[0002] For example, a portable cutting machine for metalworking, known as a chip saw cutter (metal cutter), has a disk-shaped cutting tool that rotates with a motor. The cutting tool cuts the material by rotating the cutting tool and moving the portable cutting machine along the cutting area. Sparks are generated at the cutting area where the cutting tool cuts. As the temperature of the sparks drops, they become high-temperature chips. Portable cutting machines are equipped with various mechanisms to prevent sparks and chips from scattering to the surrounding area. For example, sparks and chips are carried by the rotating air of the cutting tool into a fixed cover that covers the area above the cutting tool. Portable cutting machines are equipped with a dust box for collecting sparks and chips. The dust box is detachable from the fixed cover. The rotating air inside the fixed cover is guided to the dust box, where the sparks and chips are collected.

[0003] The dust box described in Patent Document 1 can be attached and detached with a single touch using a locking member that slides left and right relative to the top of the fixed cover. The dust box has three positioning parts for positioning it on the fixed cover, separate from the locking member. First, the dust box is positioned relative to the fixed cover using the three positioning parts, and then the dust box can be fixed using the locking member. Therefore, there is room for improvement in the dust box positioning structure. In addition, the dust storage section of the dust box is made of synthetic resin. Therefore, there is room for improvement in heat resistance.

[0004] The dust box described in Patent Document 2 can be attached and detached by operating a thumb screw on the side of the fixed cover. Therefore, there is room for improvement in the ease of attachment and detachment. The dust box also has a half-split housing made of synthetic resin and an aluminum die-cast part installed inside the housing. The aluminum die-cast part is attached in close contact with the inner wall of the half housing farther from the cutting tool. Because heat transferred from high-temperature sparks and chips to the aluminum die-cast part is also transferred to the half housing, there is room for improvement in heat countermeasures. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-196310 [Patent Document 2] Japanese Patent Application Publication No. 2023-178720 Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, there is a demand for a portable cutting machine equipped with a dust box that can be easily attached to and detached from the cutting machine body. [Means for solving the problem]

[0007] According to one aspect of the present disclosure, a portable metalworking cutter has a cutter body and a dust box detachable from the cutter body. A cutting tool is rotatably attached to the cutter body. The dust box has a first housing, a second housing, and an inner plate. The first housing is made of synthetic resin and has a first side located inside the cutter body. The second housing is made of synthetic resin and has a second side opposite the first side and is interconnected with the first housing. The inner plate is provided with an air gap between it and the second side.

[0008] Therefore, sparks and chips generated when the cutting tool cuts the material are mainly blown toward the inner plate, away from the cutting tool, by the rotating wind. By creating an air gap between the inner plate and the second side, the heat from the sparks and chips can be prevented from being transmitted to the second housing. This makes it easier for the operator to grip the dust box, improving the workability of attaching and detaching the dust box to the cutting machine body. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a right side view of a portable cutting machine according to an embodiment of the present disclosure. [Figure 2] FIG. 1 is a top view of a portable cutting machine. [Figure 3] FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. [Figure 4] FIG. 4 is an enlarged view of part IV in FIG. [Figure 5] 3 is a cross-sectional view taken along line VV in FIG. 2. [Figure 6] FIG. 6 is an enlarged view of a portion VI in FIG. 5. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 8 is an enlarged view of part VIII in FIG. [Figure 9] FIG. 1 is a left side view of the portable cutting machine excluding the motor housing, electric motor, and handle housing. [Figure 10] 10 is an exploded perspective view of the dust box in the state of FIG. 9, with the dust box removed from the fixed cover. [Figure 11] FIG. 2 is an exploded perspective view of the dust box as seen from the left rear. [Figure 12] FIG. 2 is an exploded perspective view of the dust box as seen from the front right. [Figure 13] 1 is a perspective view of a stationary cutter in which a portable cutter is mounted on a stand according to a first embodiment, when the portable cutter is positioned at the top dead center. FIG. [Figure 14] FIG. 10 is a right side view of the portable cutting machine at the top dead center. [Figure 15]FIG. 1 is a view from the operator's side when the portable cutting machine is at the top dead center. [Figure 16] FIG. 1 is a view of the portable cutting machine at the top dead center as seen from the side opposite the operator. [Figure 17] FIG. [Figure 18] 19 is a view of the stand and the base member of the portable cutter when the protruding portion of the mounting arm is inserted into the circular hole of the base member, as viewed from the XIX direction in FIG. 14. [Figure 19] 19 is a view of the stand and the base member of the portable cutting machine when the base member is fixed to the mounting arm, as viewed from the XIX direction in FIG. 14. [Figure 20] 20 is a cross-sectional view taken along the line XX-XX in FIG. 19. [Figure 21] 10 is a right side view excluding the dust box when the tip of the link arm is at top dead center before engaging with the engaging portion of the movable cover. FIG. [Figure 22] 10 is a right side view excluding the dust box when the movable cover is open and the tip of the link arm is at top dead center just before engaging with the engaging portion of the movable cover. FIG. [Figure 23] 10 is a right side view showing the dust box removed at the top dead center with the tip of the link arm engaged with the engaging portion of the movable cover. FIG. [Figure 24] FIG. 10 is a right side view of the portable cutter when it is moved downward from the top dead center so that the cutting tool cuts into the workpiece. [Figure 25] FIG. 10 is a right side view of the portable cutting machine at the bottom dead center. [Figure 26] 14 is an enlarged view of the portable cutter at the bottom dead center as viewed from the direction XXVI in FIG. 13. [Figure 27] FIG. 14 is an enlarged view of the dust guide as viewed from the direction XXVII in FIG. 13. [Figure 28] 16 is a cross-sectional view of the portable cutter and the dust guide taken along line XXVIII-XXVIII in FIG. 15. [Figure 29] FIG. 10 is a right side view of the stationary cutter with the portable cutter mounted on the stand according to the second embodiment, when the portable cutter is positioned at the top dead center. [Figure 30]10 is a right side view excluding the dust box when the tip of the link arm is at top dead center before engaging with the engaging portion of the movable cover. FIG. [Figure 31] FIG. 10 is a right side view, excluding the dust box, of the portable cutting machine when it is moved toward the side opposite the operator and is at top dead center just before the tip of the link arm engages with the engaging portion of the movable cover. [Figure 32] FIG. 10 is a right side view of the portable cutting machine, excluding the dust box, at top dead center with the tip of the link arm engaged with the engaging portion of the movable cover after being moved toward the side opposite the operator. [Figure 33] FIG. 10 is a right side view of the portable cutter when it is moved downward from the top dead center so that the cutting tool cuts into the workpiece. [Figure 34] FIG. 10 is a right side view of the portable cutting machine at the bottom dead center. [Figure 35] FIG. 11 is a right side view of a stationary cutter with a portable cutter mounted on a stand according to a third embodiment, when the portable cutter is positioned at the top dead center. [Figure 36] 10 is a right side view of the movable cover when it is open and the tip of the link arm is at top dead center just before engaging with the engaging portion of the movable cover. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] According to another feature of the present disclosure, an upper opening of the dust collection chamber is formed between the first side surface and the inner plate. Therefore, sparks and chips can be more reliably guided into the dust collection chamber. The dust collection chamber is thermally protected by providing an air layer between the inner plate and the second side surface to prevent the second side surface from becoming hot. Therefore, high-temperature chips can be stored in the dust collection chamber while maintaining a comfortable usability of the dust box.

[0011] According to another feature of the present disclosure, the inner plate is made of aluminum. Therefore, the inner plate has high thermal conductivity, which prevents localized temperature rises. This results in a uniform temperature distribution on the inner plate. Furthermore, the rotating airflow from the cutting tool hits the entire inner plate. This improves the cooling efficiency of the inner plate.

[0012] According to another feature of the present disclosure, the thickness of the inner plate is uniform, which can prevent local temperature rises in the inner plate, resulting in a uniform temperature of the inner plate.

[0013] According to another feature of the present disclosure, the thickness of the inner plate is 0.3 mm to 1.0 mm. This allows the inner plate to be lightweight, thereby reducing the weight of the dust box. Also, it becomes easier to provide an air layer of a predetermined thickness or more between the inner plate and the second side surface.

[0014] According to another feature of the present disclosure, the inner plate is made of aluminum with a surface emissivity of 0.2 or less. Therefore, by lowering the surface emissivity of the inner plate, less heat is radiated as electromagnetic waves from the inner plate when the temperature of the inner plate rises. This prevents the first and second housings from heating up due to radiant heat from the inner plate.

[0015] According to another feature of the present disclosure, a spacer, which may be integral with the second housing or separate from the second housing, is provided between the inner plate and the second side surface, thereby maintaining the thickness of the air layer at a predetermined level or above.

[0016] According to another feature of the present disclosure, the spacer is a rib that is integral with the second housing. Therefore, the air layer can be formed without increasing the number of parts. The reduced number of parts improves the ease of assembly of the dust box.

[0017] According to another feature of the present disclosure, the inner plate is pressed against the first housing by the spacer. Therefore, the inner plate can be held simply by sandwiching it between the spacer of the second housing and the first housing. This allows the dust box to be provided with a simple structure and prevents heat from accumulating inside.

[0018] According to another feature of the present disclosure, the first housing, the inner plate, and the second housing are integrated by screwing the second housing to the first housing, thereby improving the work efficiency of assembling the dust box.

[0019] According to another feature of the present disclosure, the bottom of the dust storage chamber of the dust box is formed by the lower part of the first housing and the lower part of the second housing, thereby improving the assembly of the dust box and forming the bottom of the dust storage chamber that stores chips and prevents them from scattering.

[0020] According to another feature of the present disclosure, the thickness of the air layer is 0.5 mm or more, which prevents the second side surface from heating up, and therefore keeps the temperature of the outer surface of the dust box at a temperature that can be easily gripped by a worker.

[0021] According to another feature of the present disclosure, the second side surface is provided with through holes that penetrate into the air layer, allowing outside air to flow into and out of the air layer through the through holes, thereby allowing the inner plate to be cooled effectively.

[0022] According to another feature of the present disclosure, a front inlet is formed in the front portion of the dust box, through which chips are fed. A through-hole is provided in a rear region of the dust box, rearward of the center of rotation of the cutting tool. Therefore, sparks and chips are fed from the front inlet to the rear region of the dust box, rearward of the center of rotation of the cutting tool, by the rotating air of the cutting tool. A through-hole is provided in a position facing the inner plate, across an air layer, in the rear region of the dust box, through which sparks and chips are fed. Therefore, the inner plate, which has been heated by the heat of the sparks and chips, can be more efficiently cooled by the outside air flowing in through the through-hole.

[0023] According to another feature of the present disclosure, a portable cutter includes a cutter body and a dust box detachable from the cutter body. A cutting tool is rotatably attached to the cutter body. The dust box has a front entrance, a front engagement portion, and a rear engagement portion. Chips are fed into the front entrance. The front engagement portion detachably engages with the cutter body in the left-right direction. The rear engagement portion detachably engages with the cutter body in the left-right direction. Either the front engagement portion or the rear engagement portion is provided with an operating portion that can be pushed to disengage from the cutter body.

[0024] Therefore, the dust box can be fixed to the cutting machine body at two locations, the front engagement portion and the rear engagement portion. This reduces the number of engagement portions and prevents the dust box from becoming larger. Furthermore, both the front engagement portion and the rear engagement portion are arranged to engage in the left-right direction, and one of them is arranged as an operating portion that can be pressed and operated. This prevents the dust box, which has the front engagement portion and the rear engagement portion, from becoming larger in the front-to-back and up-to-down directions. This improves the workability of attaching and detaching the dust box to the cutting machine body.

[0025] According to another feature of the present disclosure, either the front engaging portion or the rear engaging portion is disposed on a first side surface of the dust box located inside the cutting machine body in the left-right direction. Therefore, the front engaging portion or the rear engaging portion is disposed by utilizing dead space inside the cutting machine body. This prevents the dust box from becoming too large.

[0026] According to another feature of the present disclosure, both the front engagement portion and the rear engagement portion are disposed on the first side surface. Therefore, by disposing both the front engagement portion and the rear engagement portion in the dead space inside the cutting machine body, it is possible to further prevent the dust box from becoming large.

[0027] According to another feature of the present disclosure, the rear engagement portion is an operating portion. Therefore, the rear region of the dust box is made heavier than the front region for dust collection. By providing the operating portion in the heavy rear region, the dust box can be balanced and carried while using the operating portion to remove the dust box.

[0028] According to another feature of the present disclosure, the operating unit has an upper push operating portion that can be pushed and a lower locking portion that engages with the cutting machine body, and the push operating portion and locking portion are integrally provided. Therefore, by providing the push operating portion at an upper position where heat from cutting chips is less likely to be transmitted, the operability of the operating unit is improved. Furthermore, the operating unit can be operated by pushing the push operating portion while holding the dust box from above. This improves the workability of attaching and detaching the dust box.

[0029] According to another feature of the present disclosure, one of the front engaging portion and the engaged portion of the cutting machine body that engages with the front engaging portion is a convex portion and the other is a concave portion, so that the front engaging portion and the engaged portion can be provided with a simple structure and can be easily positioned.

[0030] According to another feature of the present disclosure, the distance between the front and rear engagement portions in the front-to-rear direction is longer than half the diameter of the cutting tool, so that by increasing the distance between the front and rear engagement portions, the dust box can be reliably positioned and fixed with fewer engagement portions.

[0031] A first embodiment of the present disclosure will be described with reference to FIGS. 1 to 28. This embodiment illustrates a portable cutting machine 1, also known as a chip saw cutter, for metalworking, and a stand 30 for the portable cutting machine that can be used as a stationary cutting machine for metalworking by mounting the portable cutting machine 1. Among stationary cutting machines for metalworking, those that use a cutting wheel as a cutting tool are referred to as "high-speed cutting machines" or "abrasive chop saws," while those that use a chip saw blade as a cutting tool are referred to as "metal cutting chop saws." The portable cutting machine 1 is supported above the stand 30 so that it can swing up and down. The cutting machine body 10 of the portable cutting machine 1 has a disk-shaped chip saw as a cutting tool 4. Hereinafter, in the description of the use of the portable cutting machine 1 alone, the cutting direction is referred to as the forward direction, and the opposite direction to the cutting direction is referred to as the rearward direction. In the explanation of using the portable cutting machine 1 as a stationary metalworking cutting machine mounted on the stand 30, the side in front where the operator is positioned is the operator's side, and the side further back from the operator's perspective is the opposite side. The up, down, left, and right directions are defined based on the viewpoint of an operator positioned behind the portable cutting machine 1 or on the operator's side of the stationary metalworking cutting machine.

[0032] As shown in Figures 1 to 3, the portable cutting machine 1 has a substantially rectangular plate-shaped base member 2 that is placed on the workpiece when used alone. The base member 2 is provided with a window 2a that penetrates the base member 2 in the vertical direction (i.e., the thickness direction) and extends generally in the front-to-rear direction. The cutting tool 4 can protrude downward from the bottom surface of the base member 2 through the window 2a. This downward protruding region of the cutting tool 4 can be used to cut into the workpiece W below the base member 2.

[0033] As shown in Figures 10 and 18, two circular holes 2b are provided in the front left portion of the base member 2, penetrating vertically. The two circular holes 2b are aligned at the same front-to-rear position with a predetermined distance between them in the left-to-right direction. Narrow holes 2c are provided in communication with the rear ends of the circular holes 2b, penetrating the base member 2 in the up-to-down direction and extending in the front-to-rear direction. The left-to-right width of the narrow holes 2c is shorter than the diameter of the circular holes 2b. A diamond-shaped hole 2d is provided in the front right portion of the base member 2, penetrating vertically. The hole 2d is longer in the front-to-rear direction than in the left-to-right direction. The left-to-right center of the hole 2d is located on an extension of the left-to-right center of the cutting tool 4 (see Figure 7). By aligning the left-to-right center of the hole 2d with the corner line of the workpiece, the cutting tool 4 can cut along the corner line. A narrow portion 2e is provided in communication with the rear end of the hole 2d, penetrating the base member 2 in the up-to-down direction and extending in the front-to-rear direction.

[0034] As shown in Figures 1, 2, and 9, a vertical swing support shaft 3 is provided on the front upper surface of the base member 2. The cutting machine body 10 can swing up and down relative to the base member 2 around the vertical swing support shaft 3. A depth guide 8b extending upward is provided on the rear of the base member 2. An arc-shaped hole is formed in the depth guide 8b, centered on the vertical swing support shaft 3, and penetrates the depth guide 8b in the left-right direction. The depth guide 8b is connected to the fixed cover 5 (described later) by a bolt 8a. A fixed lever 8 is connected to the bolt 8a so that it can swing up and down. When the fixed lever 8 is rotated in the tightening direction, the vertical swing position of the cutting machine body 10 relative to the depth guide 8b is fixed. This fixes the protruding length of the cutting tool 4 from the underside of the base member 2. Therefore, the cutting depth of the cutting tool 4 is fixed. When the fixed lever 8 is rotated in the loosening direction, the cutting machine body 10 can swing up and down relative to the depth guide 8b. This allows the cutting depth of the cutting tool 4 to be changed. In each of the drawings of this embodiment, the cutting machine body 10 is shown fixed to the base member 2 at the bottom dead center.

[0035] As shown in Figures 1, 5, 7, and 10, the cutting machine body 10 of the portable cutting machine 1 has a fixed cover 5 that covers the area above the cutting tool 4. A dust box 20 can be attached and detached to the fixed cover 5. The dust box 20 collects sparks generated when the cutting tool 4 cuts the workpiece W and chips generated when the sparks cool. The dust box 20 will be described in detail later. A dust feed passage 5a extending vertically is provided in front of the fixed cover 5. The lower end of the dust feed passage 5a is located directly above the window 2a of the base member 2 when the cutting machine body 10 is at bottom dead center. The cutting tool 4 rotates counterclockwise in Figure 1. Sparks and chips generated when the cutting tool 4 cuts into the workpiece W are carried upward into the dust feed passage 5a as the cutting tool 4 rotates. An upper opening 5b in the shape of a rectangular through-hole is provided at the upper end of the dust feed passage 5a.

[0036] As shown in Figures 1, 7, and 9, a movable cover 6 is attached to the fixed cover 5, which rotates to open and close the area below the cutting tool 4. The movable cover 6 closes by rotating counterclockwise in Figure 1, covering the area below the cutting tool 4. The movable cover 6 opens by rotating clockwise in Figure 1, exposing the area below the cutting tool 4 depending on the amount of opening. The center of rotation 6a of the movable cover 6 is coaxial with the center of rotation 4a of the cutting tool 4. The movable cover 6 is biased in the closing direction by a tension spring 6d, and is normally in the closed position. The tip of the movable cover 6 in the closing direction is provided with a tip 6b that can abut against the workpiece W. By moving the portable cutting machine 1 forward (in the cutting direction) relative to the workpiece W, the tip 6b is pressed against the side of the workpiece W. This causes the movable cover 6 to rotate in the opening direction against the biasing force.

[0037] 1, the movable cover 6 is provided with a cylindrical engaging portion 6c that protrudes to the right. The engaging portion 6c is provided near the rotation center 6a and in a position that does not interfere with the fixed cover 5 and the dust box 20 when the movable cover 6 rotates. The engaging portion 6c releasably engages with a link arm 34 of the stand 30, which will be described later.

[0038] 1 and 7, the cutting tool 4 is attached to an output shaft (not shown) by a fixing screw 7. The center of the fixing screw 7 is coaxial with the rotation center 4a of the cutting tool 4. The cutting tool 4 is fixed to the output shaft while being sandwiched between an outer flange 7a and an inner flange 7b.

[0039] As shown in FIG. 2 , a gear housing 13 is provided on the left side of the fixed cover 5. The gear housing 13 houses a reduction gear train (not shown). The front portion of the gear housing 13 is connected to the vertical swing support shaft 3 so as to be able to swing up and down. A substantially cylindrical motor housing 11 is provided on the left side of the gear housing 13. The motor housing 11 houses an electric motor 12, known as a DC brushless motor. The rotational drive of the electric motor 12 is reduced in speed via the reduction gear train of the gear housing 13 and transmitted to the output shaft, thereby rotating the cutting tool 4. A battery mounting section 14 is provided behind the motor housing 11. A rechargeable battery 15 can be removably mounted in the battery mounting section 14 as a power source. The battery 15 can be mounted in the battery mounting section 14 by sliding it from left to right. The battery 15 can be removed from the battery mounting section 14 by sliding it from right to left.

[0040] As shown in FIGS. 1 and 2 , a handle housing 16 is provided on top of the cutting machine body 10. The handle housing 16 is provided above the motor housing 11, the gear housing 13, and the battery mounting portion 14 so as to straddle them in the front-to-rear direction. The handle housing 16 is provided with a loop-shaped main handle 16a that extends in the front-to-rear direction. When using the portable cutting machine 1 alone, the operator can grasp the main handle 16a to carry it or move the portable cutting machine 1 forward in the cutting direction. When the portable cutting machine 1 is attached to a stand 30 and used as a stationary cutting machine, the operator can grasp the main handle 16a to swing the portable cutting machine 1 up and down relative to the stand 30.

[0041] As shown in Figure 1, a trigger 17 is provided on the inner periphery of the upper loop-shaped main handle 16a. When the trigger 17 is pulled with the fingertips of the hand holding the main handle 16a, the electric motor 12 (see Figure 2) starts and the cutting tool 4 rotates. A lock-off button 18 that can be pressed left or right is provided above the trigger 17. Pressing the lock-off button 18 releases the locked state of the trigger 17, allowing it to be pulled. This prevents the trigger 17 from being pulled inadvertently. A cylindrical sub-handle 16b is provided at the front of the handle housing 16.

[0042] As shown in Figures 9 and 10, the cutting machine body 10 has a shaft lock 19. The shaft lock 19 is mounted on the gear housing 13 so as to be slidable in a direction perpendicular to the output shaft. The operating portion of the shaft lock 19 is exposed from the front lower portion of the gear housing 13. The shaft lock 19 has a two-sided width portion 19a inside the gear housing 13. The two-sided width portion 19a has two flat surfaces that face each other and extend parallel to each other. The shaft lock 19 is biased downward and forward in the sliding direction by a compression spring 19b. When the shaft lock 19 is pushed forward and rearward against the biasing force, the two-sided width portion 19a moves toward the rotation shaft of one of the gears in the reduction gear train. The gear's rotation shaft has a two-sided width portion that can engage with the two-sided width portion 19a. Therefore, by pushing the shaft lock 19 against the biasing force, the rotation of each gear in the reduction gear train and the output shaft can be restricted. At this time, the fixing screw 7 (see FIG. 1) can be removed from the output shaft and the cutting tool 4 can be replaced.

[0043] As shown in Figures 1, 9, and 10, the dust box 20 is removably attached to the fixed cover 5 so as to cover the fixed cover 5 from above. The top, left, and right sides of the dust box 20 cover the top, left, and right sides of the fixed cover 5 from the outside, respectively. The front end of the dust box 20 is located at approximately the same position as the front end of the fixed cover 5. The rear end of the dust box 20 is located behind the rear end of the fixed cover 5. A connecting port 21i that opens downward is provided at the front of the dust box 20. A front inlet 21j that communicates with the interior of the dust box 20 is provided above the connecting port 21i (see Figure 12). By connecting the connecting port 21i to the upper opening 5b of the fixed cover 5, a dust collection path for sparks and chips is formed that connects the cutting point of the workpiece W with the cutting tool 4 to the dust box 20 via the dust feed passage 5a. 12, sparks and chips move upward from connecting port 21i to front entrance 21j as indicated by the white arrows, and then move rearward from front entrance 21j through the upper part of dust box 20. The lower rear part of dust box 20 is dust storage chamber 20a where chips accumulate.

[0044] As shown in FIGS. 10 to 12, the dust box 20 has a left-right half-split structure formed by assembling a first housing 21 on the left side and a second housing 22 on the right side. The first housing 21 is closer to the gear housing 13 than the second housing 22. The first housing 21 and the second housing 22 are made of synthetic resin. For example, the first housing 21 can be made of glass fiber-reinforced polyamide, which has high heat resistance, and the second housing 22 can be made of transparent polycarbonate without glass fiber to improve visibility. To further improve heat resistance, both the first housing and the second housing may be made of glass fiber-reinforced polyamide. To further improve visibility, both the first housing and the second housing may be made of transparent polycarbonate without glass fiber.

[0045] As shown in FIGS. 10 to 12 , the first housing 21 and the second housing 22 are connected by a plurality of screws 28. The plurality of screws 28 are fastened at four locations, for example, the front, rear, top, and bottom of the dust box 20. The first housing 21 has through-holes 21p penetrating in the left-right direction at four locations for attaching the screws 28. The second housing 22 has threaded holes 22h extending in the left-right direction at four locations for attaching the screws 28. The screws 28 are fastened by being inserted from the first housing 21 side on the left to the second housing 22 side on the right. The through-holes 21p and threaded holes 22h at the front, rear, and top of the dust box 20 are provided on bosses protruding outward from the first housing 21 and the second housing 22. This reduces the structure that obstructs the flow of air in the dust collection path inside the dust box 20.

[0046] As shown in FIGS. 10 to 12, the first housing 21 has a first side surface 21a at its left end. The first side surface 21a stands upright and extends generally in the front-to-rear direction. The connecting port 21i and the front inlet 21j are provided in the front portion of the first housing 21. A passage that communicates with the front inlet 21j and extends in the front-to-rear direction above the fixed cover 5 is provided in the upper portion 21k of the first housing 21. The passage is provided in the right portion of the first housing 21 and communicates with the front inlet 21j. The right portion of the first housing 21 is provided with multiple ribs 21b extending rightward. The multiple ribs 21b extend rightward by a length that allows them to come into close contact with the inner plate 25 (described later). Specifically, as shown in FIGS. 4, 6, and 8, the tip of the rib 21b, a surface-perpendicular positioning portion 21c at the radially inner end of the cutting tool 4, comes into close contact with the inner plate 25 on the right side. The radially outer side of the cutting tool 4 extends further to the right, forming a step, and the inner side of the step is in close contact with the inner plate 25 at the planar positioning portion 21d. That is, the planar positioning portion 21d restricts the movement of the inner plate 25 in the planar direction (the direction parallel to the radial direction of the cutting tool 4). As shown in FIG. 9, the lower portion 21m of the first housing 21 is located to the right of the rear of the fixed cover 5. In addition to 21c, other positioning portions in the planar direction are provided, including 21e near the center in the front-to-rear direction, 21f slightly rearward, 21g at the upper rear portion, and 21h at the lower rear portion, each of which protrudes rightward.

[0047] As shown in FIGS. 1, 11, and 12, the second housing 22 has a second side surface 22a at its right end. The second side surface 22a stands upright in the vertical direction and extends in the front-rear direction. The upper portion 22f of the second housing 22 cooperates with the upper portion 21k of the first housing 21 to form a dust collection path extending in the front-rear direction. The second housing 22 has multiple ribs (spacers) 22b extending leftward from the second side surface 22a. The multiple ribs 22b are integrally formed from the same material as the second side surface 22a. The multiple ribs 22b extend leftward by a length that allows them to come into close contact with the inner plate 25. As shown in FIGS. 4, 6, and 8, the multiple ribs 22b face the surface-perpendicular direction positioning portions 21c of the multiple ribs 21b of the first housing 21 in the left-right direction. The multiple ribs 22b and the multiple surface-perpendicular direction positioning portions 21c cooperate to press the inner plate 25 against each other in the left-right direction, sandwiching it. That is, the movement of the inner plate 25 in the plane perpendicular direction (the plane perpendicular direction of the cutting tool 4) is restricted by the multiple ribs 22b and the multiple plane perpendicular direction positioning portions 21c. Similar to the rib 21b, plane direction positioning portions 22c and 22d are provided on the upper and rear portions of the rib 22b. The plane direction positioning portion 21d of the first housing 21 and the plane direction positioning portions 22c and 22d of the second housing 22 cooperate to restrict the movement of the inner plate 25 in the plane direction.

[0048] As shown in Figures 1, 5, 11, and 12, a plurality of through holes 22e penetrating in the left-right direction are provided in the rear portion of the second side surface 22a. The plurality of through holes 22e are provided in the rear region 20e, which is rearward of the rotation center 4a of the cutting tool 4. Each through hole 22e opens in a rectangular shape that is long in the front-rear direction. Outside air flows into the air layer A through the through holes 22e. Air also flows out from the air layer A to the outside through the through holes 22e. A lower portion 22g of the second housing 22 is located below the plurality of through holes 22e. The lower portion 22g is connected to the lower portion 21m of the first housing 21 in the left-right direction. The lower portion 22g and the lower portion 21m cooperate to form the bottom portion 20c of the dust collection chamber 20a. The dust collection chamber 20a can store chips generated during cutting of the workpiece W.

[0049] As shown in Figures 3 to 8, 11, and 12, a flat inner plate 25 is provided between the first housing 21 and the second housing 22 in the left-right direction. The inner plate 25 is provided in a shape and size that covers the lower region of the second side surface 22a. The inner plate 25 overlaps all of the through holes 22e in the front-rear and up-down directions. The inner plate 25 is provided with a uniform thickness in the left-right direction. The thickness of the inner plate 25 has a lower limit of 0.3 mm, for example, and an upper limit of 1.0 mm, for example.

[0050] The inner plate 25 shown in FIGS. 3 to 8, 11, and 12 is made of a material with low emissivity and surface properties. The emissivity of the surface of the inner plate 25 is, for example, 0.3 or less, and more preferably 0.2 or less. By reducing the emissivity of the surface of the inner plate 25, less heat is radiated as electromagnetic waves from the inner plate 25 when the temperature of the inner plate 25 rises. The inner plate 25 is made of a metal such as aluminum, iron, or magnesium, and is more preferably made of aluminum. An aluminum inner plate 25 is preferable because the higher the purity, the lower the emissivity. A polished surface of the inner plate 25 is preferable because the emissivity can be reduced. A non-oxidized surface of the inner plate 25 is preferable because the emissivity can be reduced. The surface of the inner plate 25 is preferably not subjected to a surface treatment such as anodizing or painting in order to avoid increasing the emissivity.

[0051] As shown in Figures 3 to 8, 11, and 12, the inner plate 25 extends in the front-rear direction substantially parallel to the second side surface 22a. The front end of the inner plate 25 abuts against the surface-direction positioning portion 21d of the rib 21b at the front end of the first housing 21. The rear end of the inner plate 25 abuts against the surface-direction positioning portion 22d at the rear end of the second housing 22. The upper and lower ends of the inner plate 25 are in close contact with the rib 22b extending in the front-rear direction. Therefore, an air layer A is formed between the inner plate 25 and the second side surface 22a, surrounded by the inner wall of the second housing 22 and the rib 22b. The air layer A is isolated from the area to the left of the inner plate 25. This prevents sparks and chips from entering the air layer A. The chips accumulate in the dust collection chamber 20a to the left of the inner plate 25. The air layer A has a uniform thickness in the left-right direction corresponding to the protruding length of the rib 22b. The lower limit of the thickness of the air layer A is, for example, 0.5 mm, for example, 1.5 mm. The upper limit of the thickness of the air layer A is, for example, 4.5 mm, for example, 2.5 mm. By providing the air layer A, it is possible to suppress the amount of heat transferred from the inner plate 25 heated by the residual heat of the accumulated chips to the second side surface 22a.

[0052] As shown in FIGS. 5 and 12, the dust collection chamber 20a is connected to the upper interior of the dust box 20 via an upper opening 20b that opens upward. The upper opening 20b is formed between the upright wall 21n of the first housing 21 and the inner plate 25 in the left-right direction. The upright wall 21n extends to the right of the cutting tool 4 in the direction of the surface of the cutting tool 4. That is, the upright wall 21n extends in the up-down and front-rear directions to the left of the inner plate 25, substantially parallel to the inner plate 25. The upright wall 21n also extends in the up-down and front-rear directions to the right of the first side surface 21a, substantially parallel to the first side surface 21a. Sparks and chips sent rearward from the front inlet 21j are sent from the upper opening 20b to the dust collection chamber 20a below, while being prevented from entering the air layer A.

[0053] As shown in Figures 1, 7, 11, and 12, a discharge door 23 is provided at the rear end of the dust box 20, allowing accumulated and cooled chips to be discharged. The discharge door 23 rotates vertically around an upper rotation shaft 23a, allowing the rear end of the dust box 20 to be opened and closed. An exhaust section 23b is provided at the bottom of the discharge door 23. The exhaust section 23b is provided behind the dust collection chamber 20a. The exhaust section 23b is provided behind the inner plate 25 and the through-holes 22e. A metal plate known as a punched metal with multiple tiny through-holes is provided in the exhaust section 23b. The rotating wind of the cutting tool 4, which carries sparks and chips to the dust collection chamber 20a, is discharged to the outside of the dust box 20 through the multiple through-holes in the punched metal.

[0054] 2, 3, 5, 7, 9, and 10, a structure is provided on the first side surface 21a of the dust box 20 to enable the dust box 20 to be attached to and detached from the fixed cover 5. A front engagement portion (recess) 26 is provided in a front region 20d of the dust box 20 forward of the rotation center 4a of the cutting tool 4. A rear engagement portion (operating portion) 27 is provided in a rear region 20e of the dust box 20 rearward of the rotation center 4a of the cutting tool 4. A distance D1 in the front-to-rear direction between the front engagement portion 26 and the rear engagement portion 27 is longer than half the diameter D2 of the cutting tool 4.

[0055] As shown in Figures 2, 3, 9, and 10, the front engagement portion 26 is positioned so as to be aligned laterally with the dust feed passage 5a when the dust box 20 is attached to the fixed cover 5. The front engagement portion 26 is a rectangular through-hole. The front engagement portion 26 penetrates the first side surface 21a in the left-right direction. A front engaged portion (convex portion) 5c protruding to the left is provided on the left side surface of the dust feed passage 5a. The front engagement portion 26 and the front engaged portion 5c engage with each other in a concave-convex manner. The cross-sectional shape of the front engaged portion 5c when viewed from the front-to-rear direction is triangular. The vertical center of the front engaged portion 5c is the ridge that protrudes most to the left. The front engaged portion 5c has an upper tapered surface 5d above the vertical center and a lower tapered surface 5e below the vertical center. The upper tapered surface 5d slopes upward to the right. The lower tapered surface 5e slopes downward to the right.

[0056] As shown in Figures 2, 5, 9, and 10, the rear engagement portion 27 is provided in a position that is aligned left and right with the upper rear end of the fixed cover 5 when the dust box 20 is attached to the fixed cover 5. The rear engagement portion 27 is provided near the top surface of the dust box 20. The rear engagement portion 27 has a lever-like structure that can rotate left and right. The rear engagement portion 27 has a push operation portion 27a at its upper part. The push operation portion 27a can be pushed to the right with the operator's finger or the like. The rear engagement portion 27 has a locking portion 27c at its lower part. The locking portion 27c protrudes to the right in a hook-like shape. The push operation portion 27a and the locking portion 27c are connected together by an arm portion 27b that extends in the vertical direction.

[0057] As shown in FIG. 5, a rotation shaft 27e is provided in the vertical center of arm portion 27b. A compression spring 27d is interposed to the right of push operation portion 27a. Compression spring 27d biases rear engagement portion 27 leftward, in the direction opposite to the pushing direction. When push operation portion 27a is pressed to the right, rear engagement portion 27 rotates around rotation shaft 27e. As a result, locking portion 27c moves leftward. When pressing push operation portion 27a stops, the biasing force of compression spring 27d causes rear engagement portion 27 to rotate so as to move push operation portion 27a leftward. As a result, locking portion 27c moves rightward.

[0058] As shown in Figures 5 and 10, a flange with a concave rear engaged portion 5f on the left side is provided at the upper rear end of the fixed cover 5. The rear engaged portion 5f is trapezoidal, with the upper base longer than the lower base. The locking portion 27c of the rear engaging portion 27 can enter the rear engaged portion 5f from the left when attaching the dust box 20 to the fixed cover 5. The entered locking portion 27c can retreat to the left from the rear engaged portion 5f when removing the dust box 20 from the fixed cover 5.

[0059] Attaching and detaching the dust box 20 to and from the fixed cover 5 will be described with reference to Figures 2 to 10. By gripping the rear of the dust box 20 with both hands while hooking your fingers around the push operation portion 27a, you can attach and detach the dust box 20 with one hand (see Figure 5). To attach the dust box 20 to the fixed cover 5, first, lower the dust box 20 from above the fixed cover 5. The dust box 20 is lowered while aligning the first side surface 21a with the left side surface of the fixed cover 5. The front engaged portion 5c gradually enters the front engaged portion 26 while the lower end of the front engaging portion 26 slides along the upper tapered surface 5d. This reduces the resistance force when the front engaged portion 26 and the front engaged portion 5c engage. This allows the front engaged portion 26 and the front engaged portion 5c to smoothly engage with each other while holding the rear of the dust box 20 with one hand.

[0060] The worker grips the dust box 20 while pressing the push operation portion 27a with his / her finger. As a result, the rear engagement portion 27 rotates against the biasing force of the compression spring 27d. The locking portion 27c moves to the left. After the front engagement portion 26 engages with the front engaged portion 5c, the worker stops pressing the push operation portion 27a with the locking portion 27c aligned horizontally with the rear engaged portion 5f. The rear engagement portion 27 rotates due to the biasing force of the compression spring 27d. The locking portion 27c moves to the left and engages with the rear engaged portion 5f. Thus, the worker can attach the dust box 20 to the fixed cover 5 simply by gripping the dust box 20 and operating the push operation portion 27a.

[0061] To remove the dust box 20 from the fixed cover 5, the operator grips the dust box 20 laterally while pressing the push operation portion 27a with a finger. The rear engagement portion 27 rotates against the biasing force of the compression spring 27d. The locking portion 27c retracts to the left of the rear engaged portion 5f. This allows the rear of the dust box 20 to be lifted upward. The front engaged portion 5c gradually retracts from the front engagement portion 26 while the lower end of the front engagement portion 26 slides along the lower tapered surface 5e. This reduces the resistance force when disengaging the front engagement portion 26 from the front engaged portion 5c. This allows the operator to smoothly disengage the front engagement portion 26 from the front engaged portion 5c while holding the rear of the dust box 20 with one hand. Thus, the operator can remove the dust box 20 from the fixed cover 5 simply by gripping the dust box 20 and operating the push operation portion 27a.

[0062] As shown in FIG. 13, the stand 30 has a base 31 on which the workpiece W can be placed. The table surface 31a extends horizontally in a flat shape. Legs 31b are provided at the four corners of the base 31. The base 31 is placed on an installation surface such as the floor by means of the four legs 31b. An opening 31c, which is a long through-hole extending from the operator side to the opposite side of the operator (hereinafter referred to as the depth direction), is provided on the right side of the table surface 31a. When the portable cutting machine 1 attached to the stand 30 is swung downward, the cutting tool 4 and a dust guide 45 (described later) enter the opening 31c.

[0063] As shown in Figures 13, 14, and 16, a swing support part 32 is provided on the side of the base 31 opposite the operator. The swing support part 32 is provided on a table surface 31a. The swing support part 32 supports the attached portable cutting machine 1 so that it can swing up and down. A bolt 32a is attached to the swing support part 32 in an orientation that extends to the left. The bolt 32a serves as a top dead center stopper and a bottom dead center stopper for the up and down swing of the portable cutting machine 1.

[0064] As shown in Figures 13, 14, and 16, a fence 46 for positioning the workpiece W is provided on the table surface 31a. The fence 46 has a contact surface 46a that contacts the workpiece W. The contact surface 46a is flat and faces the operator, extending in an upright direction. A rotation support shaft 46b of the fence 46 is provided near the opening 31c. The fence 46 rotates horizontally around the rotation support shaft 46b and slides relative to the table surface 31a of the base 31. This allows the angle of the contact surface 46a to be changed in the left-right direction perpendicular to the cutting tool 4. For example, the angle of the contact surface 46a when perpendicular to the cutting tool 4 is 0°. At this time, the cutting tool 4 cuts the workpiece W that contacts the contact surface 46a at a right angle. For example, when the contact surface 46a is tilted at 45° toward the front left relative to the cutting tool 4, the angle of the contact surface 46a is 45°. At this time, the cutting tool 4 makes a 45° slant cut (miter cut) on the workpiece W that is in contact with the contact surface 46a.

[0065] 13, 14, and 16, the fence 46 has a lever 46c that can rotate horizontally on the side opposite the operator from the contact surface 46a. When the lever 46c is rotated in the tightening direction, the fence 46 is pressed toward the table surface 31a. This secures the fence 46 to the table surface 31a. When the lever 46c is rotated in the loosening direction, the pressure that presses the fence 46 toward the table surface 31a is released. This allows the fence 46 to rotate around the rotation support shaft 46b.

[0066] As shown in FIGS. 13 and 14 , a vise device (horizontal vise) 47 is provided on the table surface 31 a. The vise device 47 has a vise plate 47 c that is slidable in the depth direction on the operator side relative to the fence 46. The vise plate 47 c is rotatably connected to a feed screw 47 b extending toward the operator. The vise plate 47 c is rotatable around a rotation support shaft 47 d extending in the depth direction. Therefore, the vise plate 47 c can be rotated to a position where its rear surface faces the abutment surface 46 a of the fence 46. The feed screw 47 b is threadedly engaged with a vise base 47 e provided at the operator side end of the base 31. A feed handle 47 a is integrally provided at the operator side end of the feed screw 47 b. By rotating the feed handle 47 a, the vise plate 47 c can be moved in the depth direction. The workpiece W placed on the table surface 31a can be fixed by sandwiching the workpiece W between the contact surface 46a of the fence 46 and the vise plate 47c.

[0067] As shown in Figures 14 to 17 and 26, the stand 30 has a mounting arm 33 that can swing up and down relative to the swing support part 32. The mounting arm 33 is connected to the swing support part 32 at a swing center 33a. The mounting arm 33 is provided in a flat plate shape extending from the swing center 33a toward the operator. The mounting arm 33 swings up and down around the swing center 33a. A top dead center abutment part 33f and a bottom dead center abutment part 33g are provided on the side of the mounting arm 33 opposite the operator. When the tip of the bolt 32a abuts against the top dead center abutment part 33f, the mounting arm 33 does not swing further upward and stops at the top dead center. When the tip of the bolt 32a abuts against the bottom dead center abutment part 33g, the mounting arm 33 does not swing further downward and stops at the bottom dead center. The mounting arm 33 is constantly biased toward the top dead center by a torsion spring 33h provided around the swing center 33a. The base member 2 of the portable cutting machine 1 can be placed on an upper surface 33b of the mounting arm 33 and detachably attached thereto.

[0068] As shown in Figures 15, 17 to 20, two nuts 41 are provided on the left side of the mounting arm 33 facing the operator. The two nuts 41 are protruding portions that partially protrude upward from the upper surface 33b of the mounting arm 33. The two nuts 41 are lined up at the same depth position with a predetermined distance between them in the left-right direction. The nuts 41 are inserted into a through hole that penetrates the mounting arm 33 in the plate thickness direction. The upper part of the nut 41 is provided as an enlarged diameter portion 41a with a larger diameter than the lower part. The enlarged diameter portion 41a is disk-shaped and approximately parallel to the upper surface 33b. The lower part of the nut 41 is provided with a diameter that can be inserted into the circular hole 2b and the narrow hole 2c of the base member 2. The enlarged diameter portion 41a is provided with a diameter that can be inserted into the circular hole 2b of the base member 2 but cannot be inserted into the narrow hole 2c. A bolt (screw member) 42 inserted upward from the underside of the mounting arm 33 is attached to the lower part of the nut 41. The nut 41 is biased toward the upper surface 33b by a biasing member 41b of a compression spring provided inside the mounting arm 33. Therefore, a clearance of about the thickness of the base member 2, for example, is maintained between the expanded diameter portion 41a and the upper surface 33b.

[0069] As shown in Figures 17 to 20, a pin 43 protruding upward and generally perpendicular to the upper surface 33b is provided on the right side of the upper surface 33b of the mounting arm 33. The pin 43 is provided at a position generally corresponding to the center of the dust guide 45 in the left-right direction. The pin 43 is cylindrical and has a diameter large enough to be inserted through the hole 2d and narrow portion 2e of the base member 2. The mounting arm 33 has an abutment surface 33c extending in the left-right direction and generally perpendicular to the upper surface 33b. The abutment surface 33c abuts against the front surface 2f of the base member 2 to prevent the base member 2 from moving further toward the side opposite the operator. An adjustment screw 44 is provided on the left side of the mounting arm 33 on the side opposite the operator. The adjustment screw 44 penetrates the abutment surface 33c with its tip facing toward the operator. The tip of the adjustment screw 44 can abut against the front surface 2f of the base member 2. The adjustment screw 44 has an operating portion 44a on the side opposite the operator that can be turned with a screwdriver or the like. By tightening or loosening the operating portion 44a, the protruding length of the adjustment screw 44 toward the operator can be finely adjusted.

[0070] Attachment and detachment of the base member 2 to the mounting arm 33 will be described with reference to Figures 15 to 20. For ease of explanation, Figures 18 and 19 only show the base member 2 of the portable cutting machine 1. However, in actual attachment and detachment operations, the base member 2 is integrally connected to the cutting machine body 10, etc. First, the operator grasps the main handle 16a with the front surface 2f of the base member 2 facing away from the operator. The base member 2 is placed at the top dead center on the upper surface 33b of the mounting arm 33, which is tilted upward toward the operator. At this time, two nuts 41 are inserted into the two circular holes 2b of the base member 2, respectively, so that the enlarged diameter portion 41a protrudes above the base member 2. The pin 43 is also inserted into the hole 2d of the base member 2.

[0071] The base member 2 is slid downward along the upper surface 33b toward the opposite side to the operator. As a result, the nut 41 enters the narrow hole 2c, and the expanded diameter portion 41a is positioned above the narrow hole 2c. The pin 43 also enters the narrow portion 2e. At this time, by operating the operating portion 44a to fine-tune the length of the adjustment screw 44 protruding toward the operator, the base member 2 rotates a small angle around the pin 43. This allows fine adjustment of the miter angle of the base member 2 relative to the mounting arm 33.

[0072] After fine-tuning the miter angle of the base member 2, rotate the two bolts 42 in the tightening direction on the underside of the mounting arm 33 facing the operator. As the bolts 42 are tightened onto the nuts 41, the nuts 41 move downward against the biasing force of the biasing member 41b. This increases the force with which the expanded diameter portion 41a and the mounting arm 33 clamp the base member 2 in the vertical direction. This secures the base member 2 to the mounting arm 33. To remove the base member 2 from the mounting arm 33, first disengage the link arm 34 and the movable cover 6 (described later). Rotate the two bolts 42 in the loosening direction. Grasp the main handle 16a and slide the base member 2 upward along the top surface 33b toward the operator. Lift the portable cutting tool 1 upward, remove the nuts 41 from the circular holes 2b, and remove the pins 43 from the holes 2d. This allows the portable cutting tool 1 to be removed from the stand 30.

[0073] As shown in Figures 14, 15, 27, and 28, the stand 30 is provided with a dust guide 45 that guides sparks and chips generated during cutting upward. The dust guide 45 is connected to the lower part of the mounting arm 33. The dust guide 45 has an arc-shaped surface 45a that conforms to the outer periphery of the movable cover 6. The arc-shaped surface 45a extends in an arc from an inlet end 45c on the lower side facing the operator to an outlet end 45d on the upper side facing away from the operator. The inner wall of the arc-shaped surface 45a is covered with sheet metal to prevent wear caused by sparks and chips. The dust guide 45 has a pair of side surfaces 45b connected to the left and right ends of the arc-shaped surface 45a. The pair of side surfaces 45b extend vertically and parallel to each other in the depth direction. The inlet end 45c faces the front end 6b of the movable cover 6 in the depth direction when it is in the closed position P1. The movable cover 6 and dust guide 45 in the closed position P1 cooperate to cover the area below the cutting tool 4. The outlet end 45d communicates with the lower end of the dust feed passage 5a of the fixed cover 5. Therefore, sparks and chips carried to the outlet end 45d along the arc-shaped surface 45a of the dust guide 45 can be guided to the upper dust feed passage 5a without scattering to the surroundings.

[0074] As shown in Figures 14, 27, and 28, the dust guide 45 is connected to the mounting arm 33 so as to be rotatable around a rotation shaft 45e at the upper part on the side opposite the worker. A spring seat 45h that protrudes toward the side opposite the worker is provided below the rotation shaft 45e. A compression spring biasing member 45g is provided between the spring seat 45h and the lower part of the mounting arm 33. The dust guide 45 is biased upward toward the worker by the biasing member 45g. A guide cover 33d is provided on the mounting arm 33. The guide cover 33d extends downward from the underside of the mounting arm 33. The guide cover 33d covers the upper parts of a pair of side surfaces 45b from the left and right outer sides. The cover undersides 33e of the guide cover 33d extend approximately parallel to the extension direction of the mounting arm 33. Stoppers 45f that protrude outward to the left and right are provided on each of the pair of side surfaces 45b. The stopper 45f comes into contact with the cover lower surface 33e, thereby restricting the dust guide 45 from rotating upward toward the operator.

[0075] When replacing the cutting tool 4 while the portable cutting machine 1 is attached to the stand 30, the dust guide 45 covers a portion of the area below the cutting tool 4. If the dust guide 45 were fixed to the mounting arm 33, it could get in the way of replacing the cutting tool 4. However, the dust guide 45 of the present disclosure can be retracted rearward, away from the operator, relative to the portable cutting machine 1. For example, the cutting tool 4 can be attached or removed by pushing the dust guide 45 rearward, away from the operator, with the outer edge of the cutting tool 4. This improves the ease of replacing the cutting tool 4. The dust guide 45 is normally biased toward the cutting tool 4 by the biasing member 45g. Therefore, the dust guide 45 can adequately suppress the scattering of sparks and chips when the cutting tool 4 cuts the workpiece W.

[0076] As shown in Figures 21 to 23, the stand 30 has a link arm 34 that releasably engages with the movable cover 6. The link arm 34 is formed in a flat plate shape and extends vertically and in the depth direction to the right of the cutting tool 4. The link arm 34 has a base 35, an arm body 36, and a tip 37. The link arm 34 is rotatably connected to the upper part of the swing support part 32 at a rotation center 35a of the base 35. The rotation center 35a of the link arm 34 is located above and slightly away from the swing center 33a of the mounting arm 33, away from the operator. When viewed from the left and right, the rotation center 35a of the link arm 34 is located above a line L that passes through the swing center 33a of the mounting arm 33 and the rotation center 6a of the movable cover 6. The arm body 36 extends a long distance from the base 35 toward the operator. The tip 37 is located at the end of the arm body 36 on the operator side.

[0077] 21 to 23, the arm body 36 extends linearly from the base 35 to near the center of rotation 4a of the cutting tool 4. An arc-shaped portion 36a is provided on the arm body 36 on the operator's side. The arc-shaped portion 36a curves upward in an arc shape so as to avoid the area around the center of rotation 4a of the cutting tool 4. This allows the cutting tool 4 to be replaced by attaching and detaching the fixing screw 7 without being obstructed by the link arm 34, while the portable cutting machine 1 is attached to the stand 30.

[0078] As shown in FIGS. 21 to 23 , the tip 37 extends downward from the arm body 36 toward the worker and is hook-shaped, bending toward the side opposite the worker toward the tip edge 37a. The tip 37 overlaps the engagement portion 6c of the movable cover 6 in the left-right direction. Therefore, the tip 37 can engage with the engagement portion 6c. An inclined portion 37b and a large inclined portion 37c are provided on the outer periphery of the tip 37, and are connected to each other. The large inclined portion 37c is provided adjacent to the tip edge 37a. The inclined portion 37b is located farther from the tip edge 37a than the large inclined portion 37c. The inclined portion 37b inclines downward toward the side opposite the worker where the base 35 is located. The large inclined portion 37c is inclined more toward the side opposite the worker where the base 35 is located than the inclined portion 37b. The inclined portion 37b inclines toward the rotation center 35a in the direction in which the movable cover 6 rotates and opens. The large inclined portion 37c is inclined more greatly toward the rotation center 35a in the direction in which the movable cover 6 rotates and opens than the inclined portion 37b. An arc-shaped inner peripheral portion 37d is provided on the inner peripheral side of the tip portion 37. The engaging portion 6c can enter the inner peripheral portion 37d.

[0079] 14, and 21 to 25, the engagement of the link arm 34 with the movable cover 6 and the opening and closing of the movable cover 6 when the portable cutter 1 is swung up and down will be described. For the sake of convenience, the dust box 20 is shown removed from the fixed cover 5 in Figures 21 to 23, but in actual operation, the dust box 20 is attached to the fixed cover 5, and this is also true for the other embodiments. First, the base member 2 is fixed to the mounting arm 33. At this time, the engagement portion 6c abuts against the inclined portion 37b, and the link arm 34 and the movable cover 6 are not yet engaged (see Figure 21).

[0080] The movable cover 6 is opened clockwise from the closed position P1 in the figure. The engaging portion 6c also moves clockwise around the rotation center 6a. As the engaging portion 6c moves, the contact point on the tip end 37 also moves. Therefore, as the movable cover 6 is opened, the engaging portion 6c slides along the inclined portion 37b, the large inclined portion 37c, and the tip edge 37a in that order (see FIG. 22). The link arm 34 rotates slightly vertically as the tip end 37 and the engaging portion 6c move relative to each other. When the engaging portion 6c moves over the tip edge 37a toward the opposite side from the operator, the link arm 34 rotates downward. The engaging portion 6c abuts against the inner peripheral portion 37d of the tip end 37. When the movable cover 6 is returned in this state in the closing direction, the movable cover 6 closes while the engaging portion 6c remains hooked on the inner peripheral portion 37d (see FIG. 23). Thus, the link arm 34 engages with the movable cover 6 simply by opening or closing the movable cover 6. When the link arm 34 is to be removed from the movable cover 6, the engagement state can be released by rotating the link arm 34 upward with the movable cover 6 open.

[0081] When the portable cutting tool 1 is at the top dead center, the movable cover 6 is in the closed position P1. As the portable cutting tool 1 and the mounting arm 33 swing up and down, the rotation center 35a of the link arm 34 and the rotation center 6a of the movable cover 6 each move around the swing center 33a of the mounting arm 33. When the portable cutting tool 1 swings downward, the rotation center 35a of the link arm 34 moves relatively farther away from the rotation center 6a of the movable cover 6 toward the side opposite the operator. Therefore, as the portable cutting tool 1 swings downward, the link arm 34 pulls the engaging portion 6c toward the side opposite the operator. This causes the movable cover 6 to rotate clockwise in the figure and open.

[0082] By lowering the portable cutting machine 1 to a predetermined height, the movable cover 6 exposes a portion of the area below the cutting tool 4. This allows the cutting tool 4 to cut into the workpiece W (see Figure 24). When the portable cutting machine 1 is lowered to the bottom dead center, the movable cover 6 opens to an open position P2, exposing almost the entire area below the cutting tool 4 (see Figure 25). Thus, the movable cover 6 can be automatically opened and closed by the link arm 34 in conjunction with the up and down swing of the portable cutting machine 1.

[0083] As described above, the portable cut-off machine 1 for metalworking has a cut-off machine body 10 and a dust box 20 that is detachable from the cut-off machine body 10, as shown in Figures 3, 5, 7, and 10-12. A cutting tool 4 is rotatably attached to the cut-off machine body 10. The dust box 20 has a first housing 21, a second housing 22, and an inner plate 25. The first housing 21 is made of synthetic resin and has a first side surface 21a located inside the cut-off machine body 10. The second housing 22 is made of synthetic resin and has a second side surface 22a opposite to the first side surface 21a, and is interconnected with the first housing 21. The inner plate 25 is provided with an air layer A between it and the second side surface 22a.

[0084] Therefore, sparks and chips generated when the cutting tool 4 cuts the workpiece are mainly blown by the rotating wind toward the inner plate 25, which is away from the cutting tool 4. By providing an air layer A between the inner plate 25 and the second side surface 22a, it is possible to prevent the heat of the sparks and chips from being transmitted to the second housing 22. This makes it easier for the worker to grip the dust box 20, improving the workability of attaching and detaching the dust box 20 to the cutting machine body 10.

[0085] 5 and 7, an upper opening 20b of the dust collection chamber 20a is formed between the first side surface 21a and the inner plate 25. This allows sparks and chips to be more reliably guided into the dust collection chamber 20a. The dust collection chamber 20a has a thermal countermeasure in place to prevent the second side surface 22a from becoming hot by providing an air layer A between the inner plate 25 and the second side surface 22a. This allows high-temperature chips to be stored in the dust collection chamber 20a while maintaining a comfortable usability of the dust box 20.

[0086] The inner plate 25 shown in Figures 3 to 7, 11, and 12 is made of aluminum. Therefore, the inner plate 25 has high thermal conductivity, which prevents localized temperature increases. This makes the temperature of the inner plate 25 uniform. Furthermore, the rotating air from the cutting tool 4 hits the entire inner plate 25. This improves the cooling efficiency of the inner plate 25.

[0087] 3 to 7, the inner plate 25 has a uniform thickness, which prevents local temperature rises in the inner plate 25. This makes the temperature of the inner plate 25 uniform.

[0088] 3 to 7, the thickness of the inner plate 25 is 0.3 mm to 1.0 mm. This allows the inner plate 25 to be lightweight, thereby reducing the weight of the dust box 20. In addition, it becomes easier to provide an air layer A of a predetermined thickness or more between the inner plate 25 and the second side surface 22a.

[0089] 3 to 7, 11, and 12 is made of aluminum with a surface emissivity of 0.2 or less. Therefore, by lowering the surface emissivity of the inner plate 25, less heat is radiated as electromagnetic waves from the inner plate 25 when the temperature of the inner plate 25 rises. This makes it possible to prevent the first housing 21 and the second housing 22 from being heated by the radiant heat of the inner plate 25.

[0090] As shown in 3 to 7 and 11, a rib (spacer) 22b integral with the second housing 22 is provided between the inner plate 25 and the second side surface 22a. Therefore, the rib 22b can maintain the thickness of the air layer A at a predetermined level or more.

[0091] 3 to 7 and 11, the spacer 22b is a rib that is integral with the second housing 22. Therefore, the air layer A can be formed without increasing the number of parts. Because the number of parts is small, the dust box 20 can be easily assembled.

[0092] 3 to 7, inner plate 25 is pressed against first housing 21 by rib 22b. Therefore, inner plate 25 can be held simply by sandwiching it between first housing 21 and rib 22b of second housing 22. This allows dust box 20 to be provided with a simple structure, and heat accumulation inside can be suppressed.

[0093] 10 to 12, by fastening the second housing 22 to the first housing 21 with screws, the first housing 21, the inner plate 25, and the second housing 22 are integrated together, thereby improving the efficiency of assembling the dust box 20.

[0094] 5, 11, and 12, the bottom 20c of the dust collection chamber 20a of the dust box 20 is formed by the lower portion 21m of the first housing 21 and the lower portion 22g of the second housing 22. Therefore, the bottom 20c of the dust collection chamber 20a can be formed to accommodate chips so as not to scatter, while improving the ease of assembly of the dust box 20.

[0095] 3 to 7, the thickness of the air layer A is 0.5 mm or more. This prevents the second side surface 22a from heating up. As a result, the temperature of the outer surface of the dust box 20 can be kept low enough that a worker can hold it, for example.

[0096] 1, 5, and 7, the second side surface 22a is provided with through-holes 22e that penetrate into the air layer A. Therefore, outside air flows into the air layer A and flows out from the air layer A through the through-holes 22e. This allows the inner plate 25 to be cooled appropriately.

[0097] As shown in Figure 12, a front inlet 21j through which chips are sent is formed in the front part of the dust box 20. As shown in Figure 1, a through hole 22e is provided in a rear region 20e of the dust box 20 rearward of the rotation center 4a of the cutting tool 4. Therefore, sparks and chips are sent from the front inlet 21j to the rear region 20e of the dust box 20 rearward of the rotation center 4a of the cutting tool 4 by the rotating wind of the cutting tool 4. The through hole 22e is provided in a position facing the inner plate 25 across the air layer A in the rear region 20e of the dust box 20 through which the sparks and chips are sent. Therefore, the inner plate 25, which has been heated by the heat of the sparks and chips, can be cooled more efficiently by the outside air flowing in through the through hole 22e.

[0098] As shown in Figures 2, 9, and 10, the portable cutting machine 1 has a cutting machine main body 10 and a dust box 20 that is detachable from the cutting machine main body 10. A cutting tool 4 is rotatably attached to the cutting machine main body 10. The dust box 20 has a front entrance 21j (see Figure 12), a front engagement portion 26, and a rear engagement portion 27. Cutting chips are sent into the front entrance 21j. The front engagement portion 26 engages with the cutting machine main body 10 in a detachable manner in the left-right direction. The rear engagement portion 27 engages with the cutting machine main body 10 in a detachable manner in the left-right direction. Either the front engagement portion 26 or the rear engagement portion 27 is provided with an operating portion that can be pushed to disengage it from the cutting machine main body 10.

[0099] Therefore, the dust box 20 can be fixed to the cutting machine body 10 at two locations, the front engagement portion 26 and the rear engagement portion 27. This reduces the number of engagement portions, preventing the dust box 20 from becoming larger. Furthermore, the front engagement portion 26 and the rear engagement portion 27 are both provided to engage in the left-right direction, and one of them is provided as an operating portion 27 that can be pressed. This prevents the dust box 20, which has the front engagement portion 26 and the rear engagement portion 27, from becoming larger in the front-to-back and up-to-down directions. This improves the ease of attaching and detaching the dust box 20 to and from the cutting machine body 10.

[0100] 2 and 9, either the front engagement part 26 or the rear engagement part 27 is disposed on the first side surface 21a of the dust box 20, which is located inside the cutting machine body 10 in the left-right direction. Therefore, the front engagement part 26 or the rear engagement part 27 is disposed by utilizing the dead space inside the cutting machine body 10. This makes it possible to prevent the dust box 20 from becoming larger.

[0101] 2 and 9, both the front engagement portion 26 and the rear engagement portion 27 are disposed on the first side surface 21a. Therefore, by disposing both the front engagement portion 26 and the rear engagement portion 27 in the dead space inside the cutting machine body 10, it is possible to further prevent the dust box 20 from becoming large.

[0102] 5 and 9, the rear engagement portion 27 is an operating portion. Therefore, the rear region 20e of the dust box 20 is made heavier than the front region 20d in order to collect dust. By providing the operating portion 27 in the heavy rear region 20e, the dust box 20 can be carried in a balanced manner when using the operating portion 27 to remove the dust box 20.

[0103] 5 and 9, the operating unit 27 has an upper push operating portion 27a that can be pushed, and a lower locking portion 27c that engages with the cutting machine body 10, with the push operating portion 27a and the locking portion 27c being integrally provided. Therefore, by providing the push operating portion 27a at an upper position where heat from chips is less likely to be transmitted, the operability of the operating unit 27 is improved. In addition, the operating unit 27 can be operated by pushing the push operating portion 27a while holding the dust box 20 from above. This improves the ease of attaching and detaching the dust box 20.

[0104] 3 and 10, one of the front engaging portion 26 and the front engaged portion 5c of the cutting machine body 10 that engages with the front engaging portion 26 is a convex portion and the other is a concave portion. Therefore, the front engaging portion 26 and the front engaged portion 5c can be provided with a simple structure and can be easily positioned.

[0105] 9, the distance D1 in the front-to-rear direction between the front engagement portion 26 and the rear engagement portion 27 is longer than half the diameter D2 of the cutting tool 4. Therefore, by increasing the distance between the front engagement portion 26 and the rear engagement portion 27, the dust box 20 can be reliably positioned and fixed with fewer engagement portions.

[0106] Next, a second embodiment of the present disclosure will be described with reference to Figures 29 to 34. A stand 50 for a portable cutting machine of the second embodiment has an attachment arm 51 and a link arm 52 instead of the attachment arm 33 and link arm 34 of the stand 30 shown in Figure 14. In the following explanation, only the parts that differ from the first embodiment will be described in detail.

[0107] As shown in Figures 28 to 32, the mounting arm 51 has substantially the same structure as the mounting arm 33 (see Figure 14). The mounting arm 51 is connected to the swing support part 32 so as to be swingable up and down around a swing center 51a. The base member 2 of the portable cutting machine 1 is fixed to an upper surface 51b of the mounting arm 51. The mounting arm 51 has a guide cover 51d that covers the outside of the dust guide 45 and a cover lower surface 51e that abuts against a stopper 45f of the dust guide 45. The mounting arm 51 differs from the mounting arm 33 in that it has a guide part 51c above the swing center 51a. The guide part 51c is cylindrical and protrudes to the right. The guide part 51c engages with the arm body 54 of the link arm 52.

[0108] As shown in Figures 29 to 34, the link arm 52 releasably engages with the movable cover 6. The link arm 52 is formed in a flat plate shape and extends in the vertical and depth directions to the right of the cutting tool 4. The link arm 52 has a base 53, an arm body 54, and a tip 55. The link arm 52 is rotatably connected to the upper part of the swing support part 32 at a rotation center 53a of the base 53. When viewed from the left and right, the rotation center 53a of the link arm 52 is located above a straight line L that passes through the swing center 51a of the mounting arm 51 and the rotation center 6a of the movable cover 6. The arm body 54 extends linearly from the base 53 toward the operator. The tip 55 is provided at the end of the arm body 54 on the operator side.

[0109] As shown in Figures 29 to 34, the arm body 54 has an elongated hole 54a and a rotation elongated hole 54b penetrating in the left-right direction on the side opposite the worker. The elongated hole 54a and the rotation elongated hole 54b each extend in an arc shape centered on the rotation center 35a. The elongated hole 54a and the rotation elongated hole 54b intersect and communicate with each other to form an L-shaped hole. The elongated hole 54a extends generally in the vertical direction and is relatively short. The rotation elongated hole 54b extends further than the elongated hole 54a. It is inclined at a small angle with respect to the longitudinal direction of the arm body 54. The rotation elongated hole 54b extends downward toward the side opposite the worker. A guide portion 51c of the mounting arm 51 is inserted into the elongated hole 54a or the rotation elongated hole 54b. The guide portion 51c slides in the extension direction of the elongated hole 54a or the rotation elongated hole 54b.

[0110] As shown in Figures 30 to 32, the tip 55 has a hook shape that bends downward and is substantially perpendicular to the arm main body 54. The tip 55 overlaps in the left-right direction so as to be able to engage with the engaging portion 6c of the movable cover 6. An abutting portion 55b that extends to the tip edge 55a is provided on the outer periphery of the tip 55. The abutting portion 55b is inclined downward with respect to the extension direction of the upper surface 51b of the mounting arm 51 so as to be inclined toward the side away from the operator where the base 53 is located. An L-shaped inner periphery portion 55c that bends on an arcuate surface is provided on the inner periphery of the tip 55. The engaging portion 6c can enter the inner periphery portion 55c.

[0111] 29 to 34, the engagement of the link arm 52 with the movable cover 6 and the opening and closing of the movable cover 6 when the portable cutting machine 1 is swung up and down will be described. First, the base member 2 is placed on the upper surface 51b of the mounting arm 51. The nut 41 is inserted into the circular hole 2b of the base member 2, and the pin 43 is inserted into the hole 2d of the base member 2 (see FIG. 18). At this time, the front surface 2f of the base member 2 has not moved to the innermost position on the side opposite the operator. The engagement portion 6c is in contact with the contact portion 55b, and the link arm 52 and the movable cover 6 are not yet engaged. The guide portion 51c is located at the intersection of the elongated hole 54a and the elongated rotation hole 54b (see FIG. 30).

[0112] The base member 2 is slid downward along the upper surface 51b toward the side opposite the operator. The engaging portion 6c moves relative to the mounting arm 51 in the direction in which the upper surface 51b extends. As the engaging portion 6c moves downward toward the side opposite the operator, it slides along the abutting portion 55b toward the tip edge 55a (see FIG. 31). At this time, the guide portion 51c moves downward relative to the elongated hole 54a. As a result, the link arm 52 moves upward relative to the portable cutting tool 1. When the engaging portion 6c further moves downward relative to the side opposite the operator and passes over the tip edge 55a, the tip 55 moves downward. The guide portion 51c moves upward relative to the elongated hole 54a. As a result, the link arm 52 moves downward relative to the portable cutting tool 1. As a result, the engaging portion 6c is hooked onto the inner peripheral portion 55c of the tip 55 (see FIG. 32). Thus, the link arm 52 engages with the movable cover 6 simply by sliding the portable cutting machine 1 relative to the mounting arm 51 .

[0113] When the portable cutting tool 1 is at its top dead center, the movable cover 6 is in the closed position P1. As the portable cutting tool 1 and the mounting arm 51 swing up and down, the rotation center 53a of the link arm 52 and the rotation center 6a of the movable cover 6 each move around the swing center 51a of the mounting arm 51. When the portable cutting tool 1 swings downward, the rotation center 53a of the link arm 52 moves relatively farther away from the rotation center 6a of the movable cover 6 toward the side opposite the operator. Therefore, as the portable cutting tool 1 swings downward, the link arm 52 pulls the engaging portion 6c toward the side opposite the operator. At this time, the guide portion 51c moves relatively upward toward the operator within the elongated rotation hole 54b. Therefore, the link arm 52, guided by the guide portion 51c and the elongated rotation hole 54b, rotates around the rotation center 53a, pulling the engaging portion 6c toward the side opposite the operator. As a result, the movable cover 6 rotates clockwise in the figure and opens.

[0114] By lowering the portable cutting machine 1 to a predetermined height, the movable cover 6 exposes a portion of the area below the cutting tool 4. This allows the cutting tool 4 to cut into the workpiece W (see Figure 33). When the portable cutting machine 1 is lowered to the bottom dead center, the movable cover 6 opens to the open position P2, which exposes almost the entire area below the cutting tool 4 (see Figure 34). Thus, the movable cover 6 can be automatically opened and closed by the link arm 52 in conjunction with the up and down swing of the portable cutting machine 1.

[0115] Next, a third embodiment of the present disclosure will be described with reference to Figures 35 and 36. A stand 60 for a portable cutting machine of the third embodiment has a link arm 61 instead of the link arm 34 of the stand 30 shown in Figure 14. In the following explanation, only the parts that differ from the first embodiment will be described in detail.

[0116] As shown in Figures 35 and 36, the link arm 61 has substantially the same structure as the link arm 34 (Figure 14). It releasably engages with the movable cover 6. The flat link arm 61 has a base 62, an arm body 63, and a tip 64. The link arm 61 is rotatably connected to the mounting arm 33 at a rotation center 62a of the base 62. When viewed from the left and right, the rotation center 62a of the link arm 61 is located above a line L passing through the swing center 33a of the mounting arm 33 and the rotation center 6a of the movable cover 6. The arm body 63 extends linearly from the base 62 toward the operator to near the rotation center 4a of the cutting tool 4. The arm body 63 has an arc-shaped portion 63a that curves upward in an arc around the rotation center 4a of the cutting tool 4. A tip 64 is provided at the end of the arm body 63 facing the operator. The link arm 61 is attached to the mounting arm 33. Therefore, when the portable cutting machine 1 is swung up and down, the link arm 61 swings together with the portable cutting machine 1. Therefore, the movable cover 6 does not automatically open or close, but swings while remaining open.

[0117] As shown in Figures 35 and 36, the tip 64 is hook-shaped and bent in an arc downward and away from the operator. The tip 64 overlaps in the left-right direction so as to be engageable with the engaging portion 6c of the movable cover 6. An abutment portion 64b extending in an arc up to the tip edge 64a is provided on the outer periphery of the tip 64. An arc-shaped inner peripheral portion 64c is provided on the inner periphery of the tip 64. The engaging portion 6c can enter the inner peripheral portion 64c.

[0118] 35 and 36, the engagement of the link arm 61 with the movable cover 6 will be described. First, the base member 2 is fixed to the mounting arm 33. The movable cover 6 is opened clockwise to the open position P2. The engaging portion 6c also moves clockwise around the rotation center 6a. At this time, the engaging portion 6c abuts against the abutment portion 64b, and the link arm 61 and the movable cover 6 are not yet engaged (see FIG. 36). When the movable cover 6 is fully opened, the engaging portion 6c moves toward the side opposite the operator from the leading edge 64a. The link arm 61 rotates downward, and the engaging portion 6c engages with the link arm 61 at the inner peripheral portion 64c (see FIG. 35). The movable cover 6 remains open at the open position P2. This allows the portable cutting machine 1 to swing downward and cut into the workpiece W.

[0119] Various modifications can be made to the portable cutting machine 1 and stands 30, 50, and 60 of the above-described embodiments. The portable cutting machine 1, known as a chip saw cutter, is illustrated. Alternatively, other portable cutting machines, such as dustproof circular saws, with detachable dust boxes may be used. For example, other portable cutting machines, such as portable circular saws, with movable covers, may be used, not just for metalworking. The portable cutting machine 1 is illustrated as being powered by a battery 15. Alternatively, a portable cutting machine connected to an AC power source may be used. This disclosure is applicable to cases where only a portable cutting machine is provided, only a stand is provided, or a stationary cutting machine equipped with a portable cutting machine and a stand is provided. The stand may be capable of mounting multiple types of portable cutting machines. The stand may be provided with a structure that allows the portable cutting machine to tilt left and right.

[0120] The illustrated embodiment shows an inner plate 25 and air layer A of uniform thickness. Alternatively, the thickness of the inner plate 25 or air layer A may be varied in each region to optimize heat dissipation. The illustrated embodiment shows ribs 22b integral with the second housing 22. Alternatively, a spacer separate from the second housing 22 may be provided. For example, the surface texture of the inner plate 25 may be varied in each region.

[0121] A configuration has been exemplified in which both the front engaging portion 26 and the rear engaging portion 27 are provided on the first side surface 21a. Alternatively, either one or both may be provided on the second side surface 22a. A configuration has been exemplified in which the rear engaging portion 27 is the operating portion. Alternatively, the front engaging portion 26 may be the operating portion. An example has been given of the lever-shaped operating portion 27 that is operated by pressing. Alternatively, for example, the operating portion may be operated by sliding when pressed. A configuration has been exemplified in which the front engaging portion 26 is a recess and the front engaged portion 5c is a protrusion. Alternatively, the front engaging portion 26 may be a protrusion and the front engaged portion 5c is a recess.

[0122] In the above example, the protrusion 41 is a nut and the threaded member 42 is a bolt. Alternatively, the protrusion 41 may be a bolt and the threaded member 42 may be a nut. Although the above example shows a configuration in which a metal plate is provided on the arc-shaped surface 45a of the dust guide 45, a configuration in which no metal plate is provided may also be used.

[0123] Plate-shaped link arms 34, 52, 61 are shown as examples. Alternatively, rod-shaped or cylindrical link arms may be provided. Link arms 34, 52 that open and close the movable cover 6 in conjunction with the up and down swing of the portable cutting machine 1 are shown as examples. Alternatively, the up and down swing of the portable cutting machine 1 may not be linked to the opening and closing of the movable cover 6. [Explanation of symbols]

[0124] 1. Portable cutting machine (for metalwork) 2...base member, 2a...window portion, 2b...circular hole, 2c...narrow hole 2d...Hole (for aligning the corner line), 2e...Narrow section, 2f...Front 3...Up and down swing support shaft 4...Cutting tool, 4a...Center of rotation 5...Fixed cover, 5a...Dust feed passage, 5b...Top opening, 5c...Front side engaged part (convex part) 5d...upper tapered surface, 5e...lower tapered surface, 5f...rear engaged portion 6... Movable cover, 6a... Rotation center, 6b... Tip, 6c... Engagement portion, 6d... Tension spring 7...Fixing screw, 7a...Outer flange, 7b...Inner flange 8...Fixing lever, 8a...Bolt, 8b...Depth guide 10…Cutting machine body 11...Motor housing 12...Electric motor 13...Gear housing 14...Battery mounting section 15...Battery 16...Handle housing, 16a...Main handle, 16b...Sub-handle 17...Trigger 18...Lock-off button 19...shaft lock, 19a...width across flats, 19b...compression spring 20...dust box, 20a...dust storage chamber, 20b...upper opening, 20c...bottom 20d...front area, 20e...back area 21...first housing, 21a...first side surface, 21b...rib, 21c...plane perpendicular direction positioning portion 21d...plane direction positioning portion, 21e, 21f, 21g, 21h...plane perpendicular direction positioning portions 21i...connection entrance, 21j...front entrance, 21k...upper part, 21m...lower part, 21n...standing wall 21p…Through hole 22... second housing, 22a... second side surface, 22b... rib (spacer) 22c, 22d... surface direction positioning portion, 22e... through hole, 22f... upper portion, 22g... lower portion 22h...Screw hole 23...discharge door, 23a...rotating shaft, 23b...exhaust section 25...Inner plate 26...Front engagement portion (recess) 27... rear engagement portion (operation portion), 27a... push operation portion, 27b... arm portion, 27c... locking portion 27d...Compression spring, 27e...Rotating shaft 28...Screw 30...(Portable cutting machine) stand 31...base, 31a...table surface, 31b...legs, 31c...opening 32...swing support portion, 32a...bolt 33...mounting arm, 33a...swing center, 33b...upper surface, 33c...butting surface 33d... guide cover, 33e... cover bottom surface, 33f... top dead center contact portion 33g...Bottom dead center contact part, 33h...Torsion spring 34...Link arm 35...base, 35a...rotation center 36...arm body, 36a...arc-shaped portion 37...Tip part, 37a...Tip edge, 37b...Slope part, 37c...Large slope part, 37d...Inner peripheral part 41... nut (protruding portion), 41a... enlarged diameter portion, 41b... biasing member 42...Bolt (threaded member) 43...Pin 44...adjusting screw, 44a...operating part 45...dust guide, 45a...arc-shaped surface, 45b...side surface, 45c...inlet end 45d...Outlet end, 45e...Rotating shaft, 45f...Stopper, 45g...Biasing member 45h...Spring support 46... fence, 46a... contact surface, 46b... rotation support shaft, 46c... lever 47... vice device, 47a... feed handle, 47b... feed screw, 47c... vice plate 47d...rotating shaft, 47e...vice base 50...(Portable cutting machine) stand 51...mounting arm, 51a...swing center, 51b...upper surface, 51c...guide portion 51d... Guide cover, 51e... Cover bottom 52...Link arm 53...base, 53a...rotation center 54...arm body, 54a...long hole, 54b...long hole for rotation 55...tip portion, 55a...tip edge, 55b...contact portion, 55c...inner peripheral portion 60...(Portable cutting machine) stand 61...Link arm 62...base, 62a...rotation center 63...arm body, 63a...arc-shaped portion 64...tip portion, 64a...tip edge, 64b...contact portion, 64c...inner peripheral portion W…Material to be cut A...Air layer D1…Distance, D2…Diameter L…straight line P1: Closed position P2...Open position

Claims

1. A portable metalworking cutting machine, a cutting machine body to which a cutting tool is rotatably attached; The cutting machine body has a detachable dust box, and the dust box includes: a first housing made of synthetic resin and having a first side surface positioned inside the cutting machine body; a second housing made of synthetic resin, the second housing having a second side opposite to the first side and connected to the first housing; A portable metalworking cutting machine having an inner plate provided with an air gap between the second side surface and the inner plate.

2. 2. The portable metalworking cutting machine according to claim 1, A portable metalworking cutting machine in which an upper opening of a dust collection chamber is formed between the first side surface and the inner plate.

3. The portable metalworking cutting machine according to claim 1 or 2, The inner plate of this portable cutting machine for metalwork is made of aluminum.

4. A portable metalworking cutting machine according to any one of claims 1 to 3, A portable metalworking cutting machine in which the inner plate has a uniform thickness.

5. A portable metalworking cutting machine according to any one of claims 1 to 4, The thickness of the inner plate is 0.3 mm to 1.0 mm.

6. The portable metalworking cutting machine according to claim 5, The inner plate is made of aluminum with a surface emissivity of 0.2 or less.

7. A portable metalworking cutting machine according to any one of claims 1 to 6, A spacer, which is either integral with the second housing or separate from the second housing, is provided between the inner plate and the second side surface.

8. 8. The portable metalworking cutting machine according to claim 7, The spacer is a rib integral with the second housing.

9. The portable metalworking cutting machine according to claim 7 or 8, The inner plate is pressed against the first housing by the spacer.

10. A portable metalworking cutting machine according to any one of claims 1 to 9, A portable metalworking cutting machine in which the first housing, the inner plate, and the second housing are integrated by screwing the second housing to the first housing.

11. 11. The portable metalworking cutting machine according to claim 10, The portable metalworking cutting machine has a bottom of a dust storage chamber of the dust box formed by the lower part of the first housing and the lower part of the second housing.

12. A portable metalworking cutting machine according to any one of claims 1 to 11, A portable metalworking cutting machine, wherein the thickness of the air layer is 0.5 mm or more.

13. A portable metalworking cutting machine according to any one of claims 1 to 12, A portable metalworking cutting machine, wherein the second side has a through hole that penetrates to the air layer.

14. 14. The portable metalworking cutting machine according to claim 13, A front inlet for feeding chips is formed at the front of the dust box, The through hole is provided in a rear area of ​​the dust box, rearward of the center of rotation of the cutting tool.

15. A portable cutting machine, a cutting machine body to which a cutting tool is rotatably attached; The cutting machine body has a detachable dust box, and the dust box includes: A front entrance where chips are fed, a front engaging portion that is detachably engaged with the cutting machine body in the left-right direction; a rear engaging portion that is detachably engaged with the cutting machine body in the left-right direction; A portable cutter, wherein either the front engaging portion or the rear engaging portion is provided with an operating portion that is disengaged from the cutter body by a pushing operation.

16. 16. The portable cutting machine of claim 15, A portable cutter in which either the front engaging portion or the rear engaging portion is disposed on a first side surface of the dust box located inside the cutter body in the left-right direction.

17. 17. The portable cutting machine of claim 16, The portable cutting machine wherein both the front engaging portion and the rear engaging portion are disposed on the first side surface.

18. A portable cutting machine according to any one of claims 15 to 17, The rear engagement portion is the operating portion of the portable cutting machine.

19. A portable cutting machine according to any one of claims 15 to 18, The operating unit has an upper push operating unit that can be pushed and a lower engaging unit that engages with the cutting machine body, and the push operating unit and the engaging unit are integrally formed into a portable cutting machine.

20. The portable cutting machine according to any one of claims 15 to 19, A portable cutter in which one of the front engaging portion and the engaged portion of the cutter body that engages with the front engaging portion is a convex portion and the other is a concave portion.

21. A portable cutting machine according to any one of claims 15 to 20, A portable cutting machine in which the distance between the front engagement portion and the rear engagement portion in the front-to-rear direction is longer than half the diameter of the cutting tool.

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