JP2018187768A - Dust collection cover of cutting machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dust collection cover used in a cutting machine for cutting stone and concrete, to collect powder dusts efficiently, capable of performing sufficient dust collection by self-dust collection without requiring the separate use of a dust collection machine (forced dust collection).SOLUTION: The inside of a dust collection cover is provided with two dust collection passages 11, 12. In the first dust collection passage 11 at the outer circumferential side, coarse powder dusts are collected, while in the second dust collection passage at the inner circumferential side, finer powder dusts are collected. The front edge of a dust collection wall part 13 partitioning the first dust collection passage 11 and the second dust collection passage 12 is located in the vicinity of a surface of a tangent S passing through a cutting part C to prevent the rebound of the coarse powder dusts.SELECTED DRAWING: Figure 1

Description

  The present invention is a dust collection cover used for a cutting machine such as a grinder mainly used for cutting processing of stone or concrete or a circular saw used for cutting processing of wood, for example, dust scattering generated at the cutting site The present invention relates to a dust collection cover for preventing dust.

  This type of cutting machine includes a rotating circular blade (rotary blade). The grinder has a circular grindstone as a cutting tool, and the circular saw has a circular saw blade. The cutting process is performed by cutting the rotary blade vertically with respect to the workpiece. When cutting, a lot of dust is generated. For this reason, conventionally, this type of cutting machine has been devised to efficiently collect dust generated by processing and maintain a good working environment, thereby increasing work efficiency. For example, Patent Document 1 below describes a technique for improving dust collection efficiency by providing two suction ports on the upstream side and the downstream side in the rotation direction of the blade.

Japanese Patent Laid-Open No. 10-113905

  However, it is necessary to further increase the dust collection efficiency in an operation where dust generation is particularly problematic, such as a stone or concrete cutting operation. The present invention is sufficient for the dust collection ability (self-dust collection) of the dust collection cover itself, even in the work where dust generation is particularly problematic, such as stone or concrete cutting work, without using a dust collector (forced dust collection). The purpose is to ensure proper dust collection.

  The above-described problems are solved by the following inventions. 1st invention is a dust collection cover used for the cutting machine provided with the circular cutter which rotates. In 1st invention, it has the structure provided with the dust collection wall part along the circumference | surroundings of a cutting tool, and provided with two dust collection paths divided by the dust collection wall part into the inner peripheral side and the outer peripheral side.

  According to the first invention, of the dust blown up from the cutting portion, coarse dust having a relatively large weight enters the dust collecting passage on the outer peripheral side by the inertial force due to the rotation of the cutting tool, and is relatively small in weight and fine. The dust can be caused to enter the dust collecting path on the inner peripheral side by the wind generated by the rotation of the cutting tool, thereby improving the dust collection efficiency. Coarse dust that has entered the dust collection path on the outer peripheral side is prevented from being returned to the cutting site by the dust collection wall, and the dust collection efficiency can also be improved in this respect.

  According to a second aspect of the present invention, in the first aspect, the upstream end of the dust collecting wall is a front intersection of the blade edge of the blade and the opening end of the dust cover in a side view that is in the direction perpendicular to the surface of the blade. It is equipped with the composition located on the tangent line which passes through. Thus, in the second aspect of the invention, the outer peripheral side of the upstream end of the dust collecting wall is used as the dust collecting port of the outer dust collecting channel, and the inner side of the dust collecting port of the outer dust collecting channel is set inside. It has a configuration in which the dust collection ports of the dust collection passage on the circumferential side are arranged in parallel.

  According to the second invention, in a cutting operation performed with the opening end of the dust collecting cover in contact with the upper surface of the cutting material, the opening end of the dust collecting cover and the outer peripheral edge (blade edge) of the cutting tool in a side view. Among the dust blown tangentially from the cutting part that coincides with the intersection on the front side, the heavy coarse particles enter the outer dust collection path by the inertial force due to the rotation of the cutting tool. Can be divided into the dust collecting path on the inner peripheral side by the wind generated by the rotation of the cutting tool, thereby increasing the dust collecting efficiency.

  According to the second invention, of the two dust collection passages, the dust collection passage on the outer peripheral side is disposed on or near the tangent line passing through the cutting site, and is arranged on the inner peripheral side. By arranging the dust outlets of the dust path side by side on the inner circumference side of the dust outlets of the dust collection path on the outer peripheral side, the inertial force or wind force due to the rotation of the cutting tool can be efficiently used in the vicinity of the cutting site. Dust can be collected by dividing into coarse dust and fine dust. In addition to a configuration in which the dust collection port on the outer peripheral side is positioned strictly on the tangent line, it should be placed at a position (near the tangent line) slightly shifted to the side (upstream or downstream) with respect to the tangent line. Thus, an equivalent effect can be obtained.

  3rd invention is a dust collection cover provided with the discharge port which can connect a dust collection bag to the downstream edge part of two dust collection paths in 1st or 2nd invention. In 3rd invention, it becomes the structure which located the discharge port behind the rotation center of the blade tool.

  According to the third aspect of the present invention, it is possible to ensure a sufficiently long dust collection path from the front side to the rear side with respect to the rotation center of the cutting tool for the two dust collection paths, thereby increasing the dust collection efficiency. be able to.

  According to a fourth invention, in the third invention, the cross-sectional area of the two dust collecting paths increases toward the discharge port.

  According to the fourth aspect of the invention, the inflow resistance to the dust discharge port can be reduced by increasing the cross-sectional area of the flow channel toward the downstream side, and as a result, the dust flows into the dust collection path on the upstream side. It is possible to enhance the dust collection efficiency by promoting the approach.

  In a third or fourth aspect of the invention, a fifth invention has a side wall portion along the surface direction of the cutting tool, and the side wall portion has a dust collection port having an intake port communicating with the outside and the inside of the dust collection cover. It is a cover. In the fifth aspect of the invention, the intake port is configured to be located in a region from the middle in the radial direction of the blade tool to the outer peripheral edge and in a region in front of the discharge port in a side view that is a direction perpendicular to the blade surface.

  According to the fifth aspect of the present invention, outside air is introduced into the dust collecting cover through the air inlet by the wind generated by the rotation of the blade, and thereby dust is efficiently collected in the dust collecting passage by the air having a sufficient air volume. The According to the fifth invention, the intake port is provided in a region extending from the radial middle of the blade to the outer peripheral edge in a side view and in front of the discharge port. For this reason, a sufficient amount of outside air can be efficiently introduced from the intake port by the wind (swirl flow) generated by the rotation of the cutting tool, and as a result, dust can be collected efficiently.

  6th invention is a dust collection cover which has a reflux path which connects the dust collection bag connected to the downstream of the dust collection path to an inlet port in 5th invention.

  According to the sixth aspect of the invention, the air in the dust collection bag is returned to the dust collection cover through the reflux path. Thereby, the pressure rise in the dust collection bag is suppressed, the flow of dust from the dust collection path into the dust collection bag can be made smooth, and in this respect, the dust collection efficiency can be increased.

  A seventh invention is the dust collection cover according to the fifth or sixth invention, wherein the dust collection cover has a guide rib for guiding the outside air that has flowed in or the recirculation air that has flowed in through the recirculation path into the dust collection path. is there.

  According to the seventh aspect of the invention, the dust that has flowed into the dust collection cover together with the outside air through the intake port is efficiently guided to the dust collection path, or collected together with the return air (the wind that flows in through the return path) through the intake port. The dust in the dust bag returned to the dust cover is efficiently guided to the dust collecting path, and the dust in the dust collecting cover can be efficiently collected through the dust collecting path.

  According to an eighth invention, in any one of the third to seventh inventions, a shielding portion that inhibits a flow of dust flowing in from the dust collecting passage is provided inside the dust collecting bag connected to the downstream side of the dust collecting passage. A dust collection cover provided.

  According to the eighth aspect of the invention, coarse dust having a large weight among the dust that has flowed into the dust bag is blown against the shielding portion and falls downward. Of the dust that has flowed into the dust bag, fine dust having a small weight is sprayed on the shielding portion, and then blown away to the back of the dust bag to be accumulated on the back side of the dust bag. Thus, the clogging of the dust collection bag can be suppressed by sorting the dust so that coarse dust is accumulated on the front side (discharge port side) and fine dust is accumulated on the back side.

  A ninth invention is the dust collection cover according to the eighth invention, wherein the both side walls of the dust collection bag are coupled to each other as a shielding part.

  According to the ninth aspect, the shielding portion can be provided with a simple configuration and low cost. The shielding part can be provided by, for example, sewing the two side wall parts of the dust collection bag together or by bonding them together.

  According to 9th invention, it is good also as a shielding part by providing so that a shielding board may be projected on the internal upper surface of a dust bag. In addition to the configuration in which the shielding portion is positioned in a plane with respect to the inflow direction of the dust, the shielding portion can be provided so as to be inclined in a direction in which the lower portion is displaced toward the back. By providing inclining in such a direction, an increase in inflow resistance due to the shielding portion can be suppressed.

  A tenth aspect of the invention is a cutting machine including the dust collecting cover according to any one of the first to ninth aspects of the invention.

  According to the tenth invention, the operational effect of any one of the first to ninth inventions described above can be obtained for the cutting machine.

It is a longitudinal cross-sectional view of the dust collecting cover which concerns on 1st Embodiment of this invention. This figure has shown the state which looked at the dust collection cover and the cutting machine from the front side. It is the side view which looked at the cutting machine and the dust collecting cover from the back side. It is a longitudinal cross-sectional view of a cutting machine. This figure has shown the state seen from the back side. It is a top view of a cutting machine and a dust collecting cover. It is the side view which looked at the dust collection cover concerning a 2nd embodiment of the present invention from the front side. It is a longitudinal cross-sectional view of the dust collection cover which concerns on 2nd Embodiment. This figure has shown the state seen from the back side. It is a top view of the cutting machine which attached the dust collecting cover which concerns on 3rd Embodiment. It is a longitudinal cross-sectional view of the dust collection cover which concerns on 3rd Embodiment. This figure has shown the state seen from the front side. It is a longitudinal cross-sectional view of the dust collection cover which concerns on 3rd Embodiment. This figure has shown the state seen from the back side. It is a longitudinal cross-sectional view of the dust collecting cover which concerns on 4th Embodiment. This figure has shown the state seen from the back side. It is a longitudinal cross-sectional view of the dust collecting cover which concerns on 5th Embodiment. This figure has shown the normal state seen from the back side. It is the top view which looked at the dust collecting cover concerning 5th Embodiment from the arrow (XII) direction in FIG.

  Next, an embodiment of the present invention will be described with reference to FIGS. In the following description, in the front-rear direction of the member or the like, the direction in which the cutting process proceeds (cutting direction) is the front side. A user is located behind the cutting machine 1. Accordingly, the left and right directions of the members and the like are used with reference to the user. In the direction in which cutting proceeds, the right side is also referred to as the front side, and the left side is also referred to as the back side. In each embodiment described below, a so-called grinder is exemplified as the cutting machine 1.

  As shown in FIGS. 3 and 4, the cutting machine 1 includes a main body portion 4 in which an electric motor 3 is housed in a cylindrical main body case 2, and a gear head 5 coupled to a front portion of the main body portion 4. A circular cutting tool (grinding stone) 7 is attached to a spindle 6 protruding from the gear head 5. A power cord 8 for supplying AC power is drawn out from the rear portion of the main body 4. The main body part 4 (main body case 2) is set to an appropriate thickness so as to function as a grip part held by the user. When the start switch provided on the main body 4 is turned on with the fingertip of the hand holding the main body 4, the electric motor 3 is started and the blade 7 rotates.

  The cutting machine 1 is provided with a dust collection cover 10 for preventing the dust generated by the cutting process from being scattered around. The dust collection cover 10 is attached so as to cover the upper side of the blade 7. A lower side of the cutting tool 7 protrudes from the lower part of the dust collecting cover 10. The protruding portion is cut into the material to be cut W to be cut. As shown in FIG. 1, when the cutting tool 7 rotates counterclockwise, the cutting part C (the part into which the cutting tool 7 is cut into the workpiece W, the upper surface of the workpiece W and the cutting edge of the cutting tool 7). The dust is blown upward on the wind (dust collecting wind) generated by the rotation of the blade 7 from the front crossing portion). The dust blown upward is collected in the dust collection cover 10 and is prevented from scattering to the surroundings. The present invention has an unprecedented feature of the dust collecting cover 10. Hereinafter, various embodiments of the dust collecting cover will be described.

  The dust collection cover 10 of 1st Embodiment has the case structure provided with the front part 10a which covers the front side of the cutting tool 7, the back part 10b which covers the back side, and the surrounding part 10c which covers the circumference | surroundings. The front surface portion 10a and the back surface portion 10b are positioned in parallel with a certain distance from each other. The front portion 10a and the lower end of the rear view 10b (the open end of the dust collecting cover 10) are brought into contact with the upper surface of the material to be cut W during cutting as shown in the figure. As a result, the left and right sides of the cut portion C are covered with the front view 10a and the back portion 10b. A peripheral portion 10c is provided across the periphery of the front portion 10a and the rear view 10b. The peripheral portion 10c is provided over the entire region from the front end to the rear end of the periphery of the front portion 10a and the back portion 10b. For this reason, the front end and the rear end of the peripheral edge portion 10c are also brought into contact with the upper surface of the workpiece W during the cutting process. Thereby, the front of the cutting part C is covered with the peripheral part 10c.

  As shown in FIG. 4, a screw-type clamp 10d is provided below the back surface 10b. The clamp portion 10 d is fastened to an attachment boss portion 5 a provided on the gear head 5 of the cutting machine 1, and the dust collection cover 10 is attached to the cutting machine 1. The dust cover 10 can be removed from the cutting machine 1 by loosening the screwing of the clamp portion 10d. A cylindrical discharge port 14 is integrally provided at the rear portion of the dust collection cover 10. A dust collection bag 9 is attached to the discharge port 14.

  As shown in FIG. 1, a dust collection wall portion 13 is integrally provided inside the dust collection cover 10. The dust collecting wall portion 13 is provided in a range from the upper part of the cutting site C to the rear end of the discharge port 14. The front end of the dust collecting wall portion 13 reaches almost on the tangent line S passing through the cutting site C. In the state where the opening end of the dust collection cover 10 is in contact with the upper surface of the material to be cut W, the cutting portion C is viewed from the side with the cutting edge of the blade 7 and the lower end of the front portion 10a (the opening end of the dust collection cover 10). ) And the front intersection with. A first dust collecting path 11 is formed on the outer peripheral side of the dust collecting wall portion 13 and between the dust collecting wall portion 13 and the surrounding portion 10c. The inner peripheral side of the dust collection wall portion 13 is a second dust collection path 12. The outer peripheral side of the front end of the dust collecting wall portion 13 is a dust collecting port 11 a of the first dust collecting passage 11, and the inner peripheral side is a dust collecting port 12 a of the second dust collecting passage 12.

  Dust (cutting powder) is generated at the cutting site C at the stage where cutting is performed by the counterclockwise rotation of the cutting tool 7 in the drawing. The dust generated at the cutting site C is blown off in the tangential S direction by the rotating momentum of the cutting tool 7. Of the dust, coarse dust having a relatively large weight is blown off along the tangent S direction by the inertial force generated by the rotation of the blade 7. The coarse dust blown off reaches the inside of the first dust collecting path 11 through the dust collecting port 11a. Of the dust, fine dust having a relatively small weight is blown upward along the circumferential direction by the rotating force of the blade 7. The fine dust blown up enters the second dust collecting path 12 through the dust collecting port 12a. As described above, the two dust collection paths 11 and 12 are arranged in the radial direction on the outer peripheral side of the cutting tool 7, so that coarse dust having a relatively large weight is transferred to the first dust collection path 11 on the outer peripheral side. The fine dust that is collected and relatively small in weight is collected in the second dust collecting passage 12 on the inner peripheral side.

  The dust collected in the first and second dust collection paths 11 and 12 is collected in the dust collection bag 9 through the discharge port 14. Part of the dust that has not been collected in the dust collection bag 9 through the first and second dust collection paths 11 and 12 is continuously returned to the front side by the wind flow caused by the rotation of the blade 7 and finally collected. Dust is collected in the dust bag 9.

  The dust collection wall portion 13 that divides the first dust collection path 11 and the second dust collection path 12 extends in a curved shape upward from the vicinity of the tangent S passing through the cutting site C. For this reason, mainly coarse dust particles that have once entered the first dust collection passage 11 through the dust collection port 11a and then bounced off the surrounding portion 10c are returned to the cutting portion C side by the dust collection wall portion 13. Is prevented. In this respect, efficient dust collection can be performed for particularly coarse dust.

  The dust bag 9 is a dust bag in which a cloth 9c is covered with a frame 9b having a connection port 9a. The dust collected from the dust collection cover 10 can be discarded from the connection port 9a.

  According to the dust collection cover 10 of 1st Embodiment comprised as mentioned above, the 1st dust collection path 11 and the 2nd dust collection path 12 are used as a dust collection path for collecting the dust which generate | occur | produced in the cutting | disconnection site | part C. By providing, dust collection performance can be further improved. According to the illustrated dust collection cover 10, among the dust blown up in the tangential S direction from the cutting part C, the coarse dust having a large weight is mainly applied to the first dust collection path 11 on the outer peripheral side by the inertial force due to the rotation of the blade 7. Fine dust that enters and has a small weight enters the second dust collecting passage 12 on the inner peripheral side mainly by wind force generated by the rotation of the blade 7, thereby increasing the dust collecting efficiency of the dust collecting cover 10. Can do.

  Moreover, according to the dust collection cover 10 of 1st Embodiment illustrated, the upstream front end part of the dust collection wall part 13 is provided in the state extended back on the tangent S which passes along the cutting | disconnection site | part C, or its vicinity. As a result, both the dust collection port 11a of the first dust collection channel 11 and the dust collection port 12a of the second dust collection channel 12 are arranged in parallel on or near the tangent line S passing through the cutting site C. In the vicinity of the cutting portion C, the inertia force or wind force generated by the rotation of the blade 7 can be efficiently used to collect the dust separately into coarse dust and fine dust.

  Moreover, according to the dust collection cover 10 of 1st Embodiment, even if it is a case where the coarse dust which entered into the 1st dust collection path 11 by the inertia force by rotation of the blade 7 hits the surrounding part 10c and bounces off, it is dust collection. It is prevented that the wall portion 13 returns to the cutting site C, and the dust collection efficiency can be improved also in this respect.

  Various modifications can be made to the first embodiment described above. For example, FIGS. 5 and 6 show the dust collection cover 20 of the second embodiment. The same members as those in the first embodiment and the configurations that do not need to be changed will be described using the same reference numerals. The dust collection cover 20 of 2nd Embodiment is equipped with the structure which added the inlet 21 to the dust collection cover 10 of 1st Embodiment.

  As shown in FIG. 5, the air inlet 21 is provided on the side wall (front portion 10 a) along the surface direction of the blade 7. The air inlet 21 is provided through the front portion 10a. With respect to the position in the normal direction passing through the center of the cutting tool 7, the air inlet 21 is located on the side of the cutting tool 7 and in the side view perpendicular to the surface of the cutting tool 7. ). As shown in the drawing, in the second embodiment, the air inlet 21 is provided at a position along the blade edge of the blade 7 in a side view and on the radially inner peripheral side with respect to the second dust collecting passage 12. The air inlet 21 is provided in an arc shape along the cutting edge of the cutting tool 7. Moreover, the air inlet 21 is provided above the cutting portion C with respect to the circumferential position of the blade 7 and on the upstream side with respect to the flow of dust.

  The inside and outside of the dust collecting cover 20 are communicated with each other through the air inlet 21. In the state where the blade 7 rotates in the counterclockwise direction in FIG. 5, outside air is sucked into the dust collecting cover 20 through the intake port 21 by the flow of wind generated by the rotation. Since the outside air is sucked into the dust collection cover 20 from the air inlet 21, it is possible to generate a flow of air with a sufficient air volume in the dust collection cover 20. The dust can be guided to the dust bag 9 side through the second dust collecting passages 11 and 12, and the dust collecting efficiency of the dust collecting cover 20 can be further increased.

  The dust collection cover 30 of 3rd Embodiment is shown by FIGS. 7-9. The dust collection cover 30 of 3rd Embodiment is equipped with the structure which added the reflux path 31 to the dust collection cover 20 of 2nd Embodiment. The same members and configurations as those exemplified above are denoted by the same reference numerals, and the description thereof is omitted. In the third embodiment, the reflux path 31 is provided between the air inlet 21 provided in the front portion 10 a of the dust collection cover 30 and the dust collection bag 9. The dust-collected air blown into the dust-collecting bag 9 is returned to the dust-collecting cover 30 through the reflux path 31. Since the air is recirculated between the dust collection cover 30 and the dust collection bag 9 by the reflux path 31, the pressure increase in the dust collection bag 9 is suppressed. Thus, a smooth flow of the wind that reaches can be secured, and thereby high dust collection efficiency can be maintained for a long time. Moreover, clogging of the fabric 9c can be mainly reduced by suppressing the pressure increase in the dust bag 9.

  The downstream side of the reflux path 31 is connected to the intake port 21. For this reason, the wind in the dust bag 9 is recirculated to the radially inner peripheral side of the blade 7 in a side view, like the outside air in the second embodiment. As shown in FIGS. 8 and 9, the intake port 21 is provided with two guide ribs 32 and 33. The two guide ribs 32 and 33 extend to both the reflux path 31 side and the second dust collection path 12 side, respectively.

  As shown in FIG. 8, the two guide ribs 32 and 33 are bent in an L shape on the reflux path 31 side (outside of the dust collection cover 30). By the upstream bent portions 32a and 33a of the two guide ribs 32 and 33, the flow of the wind (refluxed air) recirculated almost horizontally from the dust bag 9 is directed upward (second dust collecting passage 12). On the other hand, as shown in FIG. 9, the downstream sides of the two guide ribs 32 and 33 are curved in an arc shape. Due to the downstream curved portions 32b and 33b of the two guide ribs 32 and 33, the recirculation air sucked from the lower suction port 21 flows toward the cutting edge side along the surface direction of the blade 7, and the second collection smoothly. It is merged with the dust collecting air in the dust passage 12. Due to the two guide ribs 32 and 33 provided in the intake port 21, the return air returned to the dust collection cover 30 through the return passage 31 is smoothly merged with the dust collection air in the second dust collection passage 12. As a result, a smooth flow of the dust collecting air in the first and second dust collecting passages 11 and 12 is ensured, and as a result, the high dust collecting efficiency of the dust collecting cover 30 can be further ensured.

  FIG. 10 shows the dust collection cover 40 of the fourth embodiment. The dust collection cover 40 of the fourth embodiment is different from the dust collection cover 30 of the third embodiment in that it has a configuration in which the flow passage cross-sectional area of the first dust collection passage 11 increases toward the discharge port 14. . In the dust collection cover 30 of the fourth embodiment, the wall thickness of the outer peripheral side wall (peripheral portion 10c) that defines the first dust collection passage 11 is gradually reduced toward the downstream side in the middle of the flow path. The thickness d0 in the vicinity of the dust collection port 11a is the thickness d1 (<d0) in the vicinity of the discharge port 14. Thereby, the flow-path cross-sectional area of the 1st dust collection path 11 becomes so large that it goes downstream. Since the flow passage cross-sectional area of the first dust collecting passage 11 increases toward the downstream side, the inflow resistance in the vicinity of the discharge port 14 is reduced, so that the flow of wind containing dust becomes smooth. For this reason, it is possible to ensure a smooth flow of the wind even in the vicinity of the discharge port 14 where the wind power is reduced, and to secure the dust collection efficiency to the dust collection bag 9.

  11 and 12 show a dust collection cover 50 of the fifth embodiment. The dust collection cover 50 of the fifth embodiment has a configuration in which the flow path cross-sectional area of the first dust collection path 11 increases toward the discharge port 14 as in the fourth embodiment. However, in 5th Embodiment, it is the structure which a flow-path cross-sectional area becomes large because the thickness of the side wall part (front part 10a) of the front side which divides the 1st dust collection path 11 becomes so small that it becomes downstream. This is different from the fourth embodiment. In the case of the fifth embodiment, the thickness d2 of the side wall near the dust collection port 11a becomes smaller toward the downstream side and becomes the thickness d3 (<d2) near the discharge port 14. Even with such a configuration, the flow passage cross-sectional area of the first dust collecting passage 11 becomes larger toward the downstream side, so that the inflow resistance in the vicinity of the discharge port 14 where the wind force is reduced is reduced, thereby the dust collecting bag 9 for dust. It is possible to secure a smooth inflow to the dust and increase the dust collection efficiency.

  In the above-described fourth and fifth embodiments, the configuration in which the flow path cross-sectional area of the first dust collecting path 11 is reduced toward the downstream side and the flow path resistance in the vicinity of the discharge port 14 is reduced is exemplified. In place of or in addition to such a configuration, for example, by reducing the thickness of the dust collection wall 13 or reducing the thickness of the front portion 10a, the flow passage cross-sectional area of the second dust collection passage 12 increases toward the downstream side. By doing so, it is possible to increase the dust collection efficiency by reducing the flow path resistance on the downstream side.

  FIG. 10 shows a dust bag 9 having a shielding portion 9d therein. This shielding part 9d can be provided by sewing the cloth forming the left and right side walls of the dust bag 9 between the left and right. As shown in the drawing, the shielding part 9d is provided in a state of projecting downward from the upper part (top plate part) inside the dust bag. Moreover, the shielding part 9d is provided in a state of being inclined in a direction reaching the back part toward the lower side. According to this shielding part 9d, the dust which flowed in on the flow of the wind from the 1st, 2nd dust collection paths 11 and 12 is sprayed. Of the dust sprayed on the shielding portion 9d, coarse dust mainly having a large weight falls downward and accumulates on the bottom. Of the dust blown against the shielding part 9d, fine dust with a small weight rides on the flow of the blown wind and flows into the back as it is.

  As described above, according to the shielding portion 9d, coarse dust and fine dust can be roughly divided and collected, thereby suppressing clogging of the dust collection bag 9 (cloth 9c). The dust collection efficiency of the dust collection bag 9 and the dust collection cover 40 can be increased. The shielding part 9d can be applied not only to the dust collection cover 40 of the fourth embodiment but also to the dust collection bag 9 connected to the dust collection covers 10, 20, 30, 50 of other forms. An effect can be obtained.

  The shielding part 9d is configured to be provided by stitching the fabric 9c between the left and right as exemplified above, or a shielding plate may be hung downward from the top part of the frame 9b to serve as a shielding part. In this case, the shielding plate may be provided so as to be tiltable back and forth, or may be provided fixed at a fixed inclination angle.

  Each embodiment described above can be further modified. For example, although the grinder used mainly for the cutting of stone or concrete is exemplified as the cutting machine 1, a dust collection cover exemplified mainly for a circular saw for wood cutting provided with a circular saw blade as a cutting tool can be applied.

  Moreover, although the outer peripheral side of the dust collecting wall part 13 provided along the surrounding part 10c illustrated the structure which makes the 1st dust collecting path 11 and the inner peripheral side the 2nd dust collecting path 12, the dust collecting wall part 13 An auxiliary dust collection wall is added along the inner peripheral side to form a first dust collection path 11 between the peripheral portion 10c and the dust collection wall 13 and the dust collection wall 13 and the auxiliary dust collection wall It is good also as a structure which divides also about the inner peripheral side of the 2nd dust collecting path 12 as the 2nd dust collecting path 12 between.

  Further, the shielding part 9d of the dust bag 9 may be omitted. When the shielding part 9d is provided in the dust bag 9 as illustrated, coarse dust is collected in the dust bag by connecting the reflux path 31 to the rear of the shielding part 9d (the back side of the dust bag 9). By dropping downward and accumulating on the bottom, it is possible to prevent mainly coarse dust from returning to the dust collecting cover through the reflux path, and in this respect also the dust collecting efficiency of the dust collecting cover is reduced. Can be increased.

  Moreover, although the structure which provided the one circular-arc shaped inlet 21 along the blade edge | tip of the blade 7 was illustrated as an inlet which connects the inside and the exterior of the said dust collection cover, as a structure which provided the several inlet Alternatively, the shape may be a configuration in which one or a plurality of intake ports of other shapes such as circular holes and square holes are provided instead of the arc-shaped long groove hole (slit shape).

  Further, the air inlet 21 and the reflux path 31 exemplified above can be applied to a dust collection cover that does not have the first and second dust collection paths 11 and 12.

W: Material to be cut C: Cutting site (intersection on the front side of the upper surface of the material W to be cut and the cutting edge of the cutting tool 7)
S: Tangent line passing through the front intersection of the open end and the blade edge in a side view (tangent line passing through the cutting part C)
DESCRIPTION OF SYMBOLS 1 ... Cutting machine 2 ... Main body case 3 ... Electric motor 4 ... Main body part 5 ... Gear head 6 ... Spindle 7 ... Cutting tool 8 ... Power cord 9 ... Dust collection bag (dust back)
9a ... Connection port, 9b ... Frame, 9c ... Fabric, 9d ... Shielding part 10 ... Dust collecting cover (first embodiment)
DESCRIPTION OF SYMBOLS 10a ... Front part, 10b ... Back part, 10c ... Surrounding part, 10d ... Clamp part 11 ... 1st dust collection path, 11a ... Dust collection port 12 ... 2nd dust collection path, 12a ... Dust collection port 13 ... Dust collection wall Part 14 ... Discharge port 20 ... Dust collecting cover (second embodiment)
21 ... Air intake 30 ... Dust collecting cover (third embodiment)
31 ... Return path 32, 33 ... Guide rib 32a, 33a ... Upstream bending part, 32b, 33b ... Downstream bending part 40 ... Dust collection cover (4th Embodiment)
50 ... dust collection cover (fifth embodiment)

Claims (10)

A dust collection cover for use in a cutting machine having a rotating circular cutting tool,
A dust collection cover provided with a dust collection wall portion along the periphery of the blade and having two dust collection paths partitioned by the dust collection wall portion on the inner peripheral side and the outer peripheral side. 2. The dust collection cover according to claim 1, wherein the upstream end of the dust collection wall portion is a side view in a direction perpendicular to the surface of the blade, and the cutting edge of the blade and the opening end of the dust collection cover. Positioned on a tangent line passing through the intersection on the front side, the outer peripheral side of the upstream end of the dust collecting wall is the dust collecting port of the outer peripheral dust collecting channel, and the dust collecting port of the outer dust collecting channel A dust collection cover in which a dust collection port of the dust collection path on the inner circumference side is arranged in parallel on the inner circumference side of the cylinder. The dust collection cover according to claim 1 or 2, wherein a discharge port to which a dust collection bag can be connected is provided at a downstream end of the two dust collection paths, and the discharge port is a rotation center of the blade tool. Dust collection cover located behind. 4. The dust collection cover according to claim 3, wherein a flow path cross-sectional area of the two dust collection paths increases toward the discharge port. The dust collection cover according to claim 3 or 4, wherein the dust collection cover has a side wall portion along a surface direction of the blade, and the side wall portion has an intake port that communicates the outside and the inside of the dust collection cover, The air intake port is a dust collection cover that is located in a region extending from the radial center of the cutting tool to the blade edge on the outer peripheral edge in a side view and in a region in front of the discharge port. 6. The dust collection cover according to claim 5, further comprising a reflux path for connecting a dust collection bag connected to the discharge port to the intake port. The dust collection cover according to claim 5 or 6, wherein the dust collection cover has guide ribs for guiding the outside air that has flowed into the inside opening of the intake port or the return air flowing through the return path to the dust collection path. cover. The dust collection cover according to any one of claims 3 to 7, wherein the dust collection bag is provided with a shielding portion that inhibits a flow of dust flowing in from the two dust collection paths inside the dust collection bag. cover. The dust collection cover according to claim 8, wherein both side wall portions of the dust collection bag are connected to each other to serve as the shielding portion. The cutting machine provided with the dust collection cover described in any one of Claims 1-9.

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