JP2015208830A - Band sawing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a band sawing machine configured so that chips (iron dust) generating during a cutting operation do not intrude onto the contact face of a rotating saw wheel and a band saw.SOLUTION: A band sawing machine 1 has the driving and driven saw wheels bridged by an annular band saw 30, a motor rotating the driving saw wheel, and a housing 6 housing the above wheels and motor. A magnet 40 or an electromagnet for adsorbing the magnetic powders generating by a cutting operation is provided between the driving saw wheel positioned on the downstream side in the go-around direction of the band saw and an opening 32. Since the chips (iron dust) generating during the cutting operation are adsorbed on the magnet, the phenomenon such that the chips intrude onto the contact face of the driving saw wheel and the band saw can be significantly suppressed.

Description

  The present invention relates to a portable band saw machine for performing processing such as cutting with a band saw stretched on a saw wheel.

  A portable band saw as shown in Patent Document 1 is widely used. The portable band saw machine 101 will be briefly described with reference to FIG. The portable band saw 101 is driven by AC power supplied by a power supply cord (not shown). When the operator operates the switch 112 in a state where power is supplied, the motor 14 disposed in the housing 106 rotates. The driving saw wheel 2 is provided at one end of the housing 106, and the driven saw wheel 3 is provided at the other end of the housing 106. The motor 14 rotates the drive saw wheel 2 by a rotation transmission mechanism (not shown). The drive saw wheel 2 that is driven to rotate transmits the rotational force to the band saw 30 and causes the band saw 30 to move around. The driven saw wheel 3 is driven to rotate by a band saw 30 that moves around. The driving saw wheel 2 and the driven saw wheel 3 are circular pulleys, and a material 200 to be cut such as an iron pipe is cut by rotating an endless band saw (band saw) 30 stretched between them. A handle portion 113 is provided at one end portion on the right side of the housing 106, and an auxiliary handle 115 extending in a direction substantially perpendicular to the cutting direction of the band saw 30 is provided near the upper left side (the other end portion).

  When cutting with the portable band saw 101, the handle 113 is held with one hand, the auxiliary handle 115 is held with the other hand, and the portable band saw 101 is moved above the workpiece 200. Then, the surface direction of the band saw 30 is positioned so as to coincide with the planned cutting surface. Then, the operator presses the switch 112 to rotate the band saw 30 in the rotation direction 31, and in this state, the portable band saw machine 101 is moved downward toward the workpiece 200. At this time, it is important to move the portable band saw 101 while the surface direction of the band saw 30 is positioned at a correct angle with the workpiece 200 such as an iron pipe (in the case of an iron pipe, the direction perpendicular to the longitudinal direction). At the time of this cutting, a force for moving the portable band saw 101 in the rotation direction 31 is applied to the material to be cut 200 by the rotation of the band saw 30, so the guide plate 110 is provided on the side to be cut. Thus, the operator presses the portable band saw 101 to the material to be cut 200 side (counter-rotation direction side), and cuts at the planned cutting surface.

JP 2004-345041 A

  When a cutting operation is performed in the conventional portable band saw 101, chips (iron powder, etc.) are generated by cutting, and the outer peripheral surface of a saw wheel (a driving saw wheel 2 and a driven saw wheel 3) that partially rotates. Between the blade saw 30 and the band saw 30 (contact surface), and may be crushed and adhere to the saw wheel. In particular, in the case of a portable band saw machine (band saw machine), the saw wheel is often made of a resin material or an aluminum alloy for weight reduction, and the saw wheel is prevented from slipping with the band saw 30 on the outer peripheral surface. For this purpose, a rubber material (not shown) is attached. If chips adhere to this rubber material, the chips will not easily fall off the rubber material, and the saw wheel may be repeatedly crushed by the rotation of the saw wheel, resulting in damage or tearing of the rubber material. was there. In addition, there is a risk of deformation such as dents and scratches on the inner peripheral surface of the band saw 30, the life of the band saw 30 is shortened, the adhesion between the band saw 30 and the rubber material is deteriorated, and the band saw 30 slips. If the band saw 30 is displaced from the correct position, the processing accuracy may be reduced. In particular, in portable band saw machines, unlike stationary band saw machines, the direction of cutting during the cutting operation is not constant, and cutting may occur in various states. It was easy for the powder to enter between the saw wheel (the driving saw wheel 2 and the driven saw wheel 3) and the band saw 30 (contact surface).

  SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and an object of the present invention is to provide a band saw machine that prevents chips (iron powder) generated during a cutting operation from entering the contact surface between the rotating saw wheel and the band saw as much as possible. Is to provide.

  Another object of the present invention is to provide a band saw machine that adsorbs chips (iron powder) generated during a cutting operation by a magnetic force.

  Still another object of the present invention is to provide a band saw machine in which a permanent magnet or an electromagnet is arranged at an effective location for adsorbing chips generated by cutting, and the iron powder is easily removed after being adsorbed. Is to provide.

  The characteristics of representative ones of the inventions disclosed in the present application will be described as follows.

  According to one aspect of the present invention, a first saw wheel (e.g., drive saw wheel) and a second saw wheel (e.g., driven saw wheel) over which an annular band saw is spanned, a motor that rotates the first saw wheel, A housing for supporting the first saw wheel, the second saw wheel and the motor, the housing having an opening for exposing the band saw between the first saw wheel and the second saw wheel, and In a band saw machine that performs a cutting operation with a band saw that is positioned, the cutting is performed between one of the first saw wheel and the second saw wheel that is located downstream of the band saw in the circumferential direction of the band saw and the opening. A magnet for adsorbing magnetic powder generated by the work was provided. By providing the magnet in this way, the chips (iron powder) generated during the cutting operation are adsorbed by the magnet, so the phenomenon that chips enter the contact surface of the rotating first or second saw wheel and the band saw is greatly increased. Can be suppressed. In addition, on the upstream side and the downstream side in the circumferential direction of the band saw at the opening, there are band saw guides for holding the band saw so as to be twisted so as to have a predetermined angle with respect to the outer peripheral guide surfaces of the first saw wheel and the second saw wheel. Provided. The magnet for attracting chips is located between the band saw guide located downstream in the circumferential direction of the saw blade and the approach point of the adjacent saw wheel and close to the side surface or the rear surface of the band saw. Provided. Since the magnet is arranged so as not to come into contact with the band saw in this way, the cutting operation is not adversely affected.

  According to another aspect of the present invention, a removable saw wheel cover that covers the saw wheel is attached to the housing of the band saw machine, and the magnet is housed in a case made of resin or non-magnetic material. Fixed to the car cover. By attaching the magnet to the saw wheel cover in this way, the present invention can be easily implemented simply by changing the structure of the saw wheel cover of the portable band saw machine that has been used in the past. be able to. At this time, the distance between the magnet and the band saw may be set in consideration of the magnitude of the magnetic force. When the band width of the band saw is W, the magnet is seen from the section perpendicular to the circumferential direction of the band saw, and the magnet is the cutting edge of the band saw. It is good to arrange | position so that a part or all of a magnet may be located in the inside of the circle within 2 W, preferably within 1 W from.

  According to still another feature of the present invention, a guide plate having a guide surface orthogonal to the circumferential direction of the band saw is provided between the guide and the opening. The band saw guide has two sets of guide rollers that rotate while pressing the outer peripheral surface and the inner peripheral surface of the band saw, and a guide bearing that holds the end of the band saw opposite to the cutting edge. Further, the magnet is a permanent magnet, and is detachably fixed to the saw wheel cover while being attached to a magnet holder made of magnetic metal. By using a magnetic magnet holder in this way, a strong magnetic field can be generated in a predetermined direction even with a non-magnetic saw wheel cover made of synthetic resin or aluminum alloy.

  According to still another feature of the present invention, a detachable battery for supplying electric power to the motor is attached to the housing, and the motor is driven by the electric power of the battery. In addition, an electromagnet is used as the magnet, and the power supply to the electromagnet is controlled in conjunction with the power supply to the motor. By using an electromagnet in this way, when the switch is turned on for cutting work, electricity can flow to the electromagnet at the same time as the saw wheel starts rotating. It can be effectively attracted to the electromagnet. When the operator turns off the switch at the end of cutting, the saw wheel stops rotating or the power to the electromagnet is cut off after a certain delay time, so that the chips attached to the electromagnet fall below the main body. Therefore, the vicinity of the electromagnet can be prevented from being filled with the adsorbed chips.

  According to the present invention, among the chips generated at the time of cutting, what has moved to the saw wheel side through the guide plate that presses the material to be cut and the band saw guide behind it can be adsorbed by the magnet. It is possible to effectively prevent chips from entering the contact surface between the rotating saw wheel and the band saw. As a result, the slip phenomenon between the band saw and the saw wheel can be largely prevented, and workability is improved. Further, since it becomes difficult for chips to enter, damage to the band saw and damage to the rubber material provided on the outer periphery of the saw wheel can be prevented, and the life of the band saw and saw wheel rubber can be greatly improved.

1 is a front view of a portable band saw machine 1 according to an embodiment of the present invention. It is a rear view of the portable band saw machine 1 which concerns on the Example of this invention. It is an arrow view of the A direction of the portable band saw machine 1 of FIG. It is sectional drawing of the BB part of the portable band saw machine 1 of FIG. FIG. 3 is a rear view of the portable band saw machine 1 with the saw wheel cover 20 open. It is a single figure of the saw wheel cover 20 of FIG. 2, Comprising: It is a figure which shows the back side (side facing a band saw). It is a principal part enlarged view of the magnet unit 40 vicinity of FIG. Please change to the arrow from the left. It is sectional drawing of the CC section of FIG. It is an expanded view of the magnet unit 40 of FIG. It is a figure for demonstrating the positional relationship of the magnet unit 40 and the band saw. It is a figure which shows the saw wheel cover 20 and the magnet unit 50 of the portable band saw machine which concern on the 2nd Example of this invention. It is a principal part enlarged view of the magnet unit 50 vicinity of FIG. It is sectional drawing of the DD section of FIG. It is a rear view of the portable band saw machine concerning the 3rd example of the present invention. It is a principal part enlarged view of electromagnet unit 60 vicinity of the portable band saw machine concerning the 3rd Example of this invention. It is an electric circuit diagram of the portable band saw machine concerning the 3rd example of the present invention. It is a front view of the conventional portable band saw 101.

  Embodiments of the present invention will be described below with reference to the drawings. In the following drawings, the same portions are denoted by the same reference numerals, and repeated description is omitted. Further, in this specification, description will be made assuming that the front, rear, left, right, and up and down directions are directions shown in the drawing.

  FIG. 1 is a front view of a portable band saw 1 according to an embodiment of the present invention. The structure of the basic mechanism portion of the portable band saw 1 is the same as that of the conventional portable band saw 101 described with reference to FIG. When viewed from the outside, the difference from the conventional portable band saw machine 1 is that the design of the exterior, for example, the shapes of the housing 6, the handle portion 13, the guide plate 10, and the like are different, and the internal structure is substantially the same. A saw wheel base 4 is provided on the right side of the housing 6 of the portable band saw machine 1 to accommodate a drive saw wheel, which will be described later, and a saw wheel base 5 is provided on the left side to accommodate a driven saw wheel, which will be described later. . The saw wheel bases 4 and 5 constitute a part of the housing (housing) in a broad sense and also serve as a frame for supporting the saw wheel. The saw wheel bases 4 and 5 and the housing 6 are integrated. Manufactured in a formula or separately. An annular band saw 30 is stretched between the driving saw wheel and the driven saw wheel. When cutting the material to be cut by the portable band saw 1, the band saw 30 rotates in the rotation direction 31, and the material to be cut is pushed in the same direction as the rotation direction 31 by this rotation. A guide plate 10 is provided on the side where the vehicle is provided. The guide plate 10 has a size set according to the size and shape of the material to be cut or the space with the material to be cut (existing pipe or the like) and the like, and is a direction orthogonal to the rotation direction 31, that is, It is configured to be adjustable in the cutting direction. Band saw guides 7 and 17 for holding and guiding the band saw 30 are provided near the lower side of the saw wheel bases 4 and 5. Here, the band saw guide 7 is fixed adjacent to the drive saw wheel 2 side of the guide plate 10. When the operator holds the handle portion 13 and the auxiliary handle 15 and operates the trigger switch 12, a motor (not shown) disposed in the housing 6 rotates. The rotational force of the motor is transmitted to the drive saw wheel 2 described later by a power transmission mechanism (not shown), and the band saw 30 is rotated by the rotation of the drive saw wheel 2. Further, as the band saw 30 rotates, a driven saw wheel 3 (described later) that is pivotally supported on the saw wheel base 5 side also rotates.

  The driving saw wheel 2 and the driven saw wheel 3 are rotating disks having a cylindrical surface on the outer periphery, and the band saw 30 is stretched along the guide surface (outer peripheral guide surface) of the band saw 30 formed on the outer periphery thereof. The The band saw 30 is a band-shaped saw blade (band saw) that is continuous in the circumferential direction, and is used as a belt on two saw wheels (pulleys), and has a saw blade cut on one side of a band-shaped steel plate. Although not shown, a saw wheel rubber is fitted on the outer peripheral surfaces of the driving saw wheel 2 and the driven saw wheel 3 so that the band saw 30 contacts the outer peripheral surface of the driving saw wheel or the driven saw wheel via the saw wheel rubber. To do. Of the band saw 30 stretched by two saw wheels, the upper side of the parallel part is located in the internal space of the housing 6 and a saw wheel cover 20 described later, and the lower side of the parallel part of the band saw 30 is exposed to the outside through the opening 32. To do. Band saw guides 7 and 17 for guiding the band saw 30 are provided on the housing 6 on the drive saw wheel 2 side and the driven saw wheel 3 side, respectively. Each of the band saw guides 7 and 17 has two sets of guide rollers (described later), and twists the band saw 30 at an angle (less than 60 degrees) with respect to the outer peripheral surface of the drive saw wheel or the driven saw wheel. In this way, the angle of the band saw 30 at the cutting site is changed. The angle of the twisted band saw 30 is an angle that is substantially parallel to the upright direction of the housing 6. As a result, the exposed band saw 30 in the opening 32 has an angle that can be pressed almost perpendicularly to the longitudinal direction (axial direction) of the workpiece 200 as shown in FIG.

  The saw wheel base 5 is provided with an illuminating device 24 for irradiating a portion cut by the band saw 30, and a light switch 25 for turning on or off the lighting device is provided in the vicinity of the illuminating device. Here, the illuminating device 24 can be composed of LEDs. Near the center of the saw wheel base 5, a speed setting knob 23 for setting the peripheral speed of the band saw 30 is provided. By rotating the speed setting knob 23, a desired motor rotation speed can be set. Below the speed setting knob 23, a tension lever 26 is provided for adjusting the position of the driven saw wheel 3 to attach or remove the band saw 30 and adjust the tension.

  FIG. 2 is a rear view of the portable band saw 1 according to the embodiment of the present invention. The back side is covered with a saw wheel cover 20 that can be opened and closed. The saw wheel cover 20 has such a shape that two circular portions 20a and 20b are connected by a connecting portion 20c so as to cover one side surfaces of the driving saw wheel 2 and the driven saw wheel 3, and these are made of metal or synthetic resin. Manufactured by integral molding. The saw wheel cover 20 is pivotally supported on the housing 6 by a hinge (see FIG. 4 to be described later) at the upper side, and the lower end portion thereof is a saw wheel base 4 by claw portions 21a and 21b (see FIG. 1). 5. A power cord 16 is attached to the back side and the upper right side of the portable band saw 1 so as to extend. In the vicinity of the center of the portable band saw machine 1, the housing 6 and the saw wheel cover 20 are exposed so that a part of the circulating and rotating band saw 30 is exposed and an opening 32 is secured for the cut material to be cut. The shape is determined. In this embodiment, the magnet unit 40 is disposed on the back side (inside) of the saw wheel cover 20 and on the drive saw wheel side.

  FIG. 3 is an arrow view of the portable band saw 1 in FIG. 1 in the A direction. The saw wheel base 4 is provided with a band saw guide 7 for sandwiching and guiding the band saw 30. The band saw guide 7 includes a front guide roller 7 a that rotates while pressing a band surface on the front side of the band saw 30 (a surface including the width direction and the rotation direction of the band, and an outer peripheral surface or an inner peripheral surface), and a rear side of the band saw 30. A guide roller 8 that rotatably holds a rear guide roller 7b that rotates while pressing the band surface, and an end portion (a narrow surface including the thickness direction and the rotation direction of the band) opposite to the cutting edge of the band saw 30. The guide rollers 7 a and 7 b and the guide bearing 8 are fixed to the saw wheel base 4 via the guide holder 9. The saw wheel base 4 is formed with a screw groove 4a parallel to the cutting direction and a guide groove 4b formed in parallel with the screw groove 4a, and the guide plate 10 is fixed to the saw wheel base 4 by two screws 36. Is done. By loosening the screws 36, the guide plate 10 can be moved in the direction of the arrow 37 (the same direction as the cutting direction), and can be individualized at any position by tightening the screws 36. The guide plate 10 is formed in an inverted J shape in the drawing of FIG. 3, and a notch 10 a for passing the band saw 30 (not shown here) is formed.

  4 is a cross-sectional view of the BB portion of the portable band saw machine 1 of FIG. 1, and more precisely, a partial cross-sectional view in which the cross section of the drive saw wheel 2 is omitted. A circular portion 20 a of a saw wheel cover 20 is attached to the saw wheel base 4, and the drive saw wheel 2 is rotatably supported by a rotating shaft (not shown) on the inner side covered with the saw wheel base 4 and the saw wheel cover 20. Is done. The driving saw wheel 2 includes a cylindrical outer peripheral portion (cylinder wall) and a lid portion that closes one end of the outer peripheral portion, and a sprocket 28 is provided on the other side of the driving saw wheel 2. A sprocket 27 that is rotated by the output of the motor is provided in the vicinity of the sprocket 28, and the driving force of the motor 14 is transmitted by passing the chain 29 to the sprockets 27 and 28, so that the drive saw wheel 2 rotates. The band saw 30 (not shown here) is bent so as to be twisted by a predetermined angle by a band saw guide 7 in the vicinity of the guide plate 10 that is stretched around the outer periphery of the drive saw wheel 2. A band saw guide 17 having two guide rollers is also provided on the driven saw wheel 3 side, and the band saw 30 is twisted by the same angle as the band saw guide 7 side. As described above, the twisting with respect to the material to be cut is performed with respect to the outer peripheral surface of the driving saw wheel 2 that drives the band saw 30 exposed at the cutting site and the outer peripheral surface of the driven saw wheel 3 with a predetermined angle. This is to ensure a sufficient cutting depth. The guide roller 7 a located on the outer peripheral side with respect to the band saw 30 and the guide roller 7 b located on the inner peripheral side are configured such that a cylindrical outer ring can be rotated and can be rotated by the guide holder 9. It is pivotally supported. The length of the guide rollers 7a and 7b in the axial direction is preferably such that the cutting edge portion of the rotating band saw 30 protrudes to the outer peripheral side. For the band saw guides 7 and 18 provided on both sides of the cutting part, guide rollers and guide bearings having the same shape including the twist angle are used.

  FIG. 3 is a rear view of the portable band saw machine 1 with the saw wheel cover 20 open. The guide rollers 17a and 17b of the band saw guide 17 are attached to the saw wheel base 5 while being inclined by the same angle so as to be parallel to the guide rollers 7a and 7b. As described above, if the band saw 30 is twisted only partly on the circumference of the band saw 30, there is a possibility that the band saw 30 may be displaced in the band thickness direction. However, the guide bearing 8 is provided above the guide rollers 7a and 7b. It is done. The guide bearing 8 holds the end of the band saw 30 opposite to the cutting edge, and holds the end so that the traveling direction of the end coincides with the circumferential direction of the guide bearing 8. The displacement to the direction and the counter-cutting edge side can be regulated, and the rotation of the band saw 30 can be guided well.

  The magnet unit 40 is newly added in this embodiment. The magnet unit 40 is basically composed of a permanent magnet, and adsorbs magnetic powder generated by cutting or cutting with a magnetic force of the permanent magnet. It is important that the magnet unit 40 is provided in the vicinity of the band saw 30, in the vicinity of the rear surface of the band saw 30, and in the circumferential position, the band saw guide 7 (guide rollers 7 a and 7 b), the drive saw wheel 2, and the band saw. It is important to be between the point where 30 contacts (“entrance point”, which will be described later).

  FIG. 5 is a rear view of the portable band saw 1 with the saw wheel cover 20 open. Here, a state in which the opened saw wheel cover 20 is removed is illustrated. From this figure, it will be understood that the band saw guide 17 is installed on the driven saw wheel 3 side. The band saw guide 17 is composed of a guide roller 17a positioned on the outer peripheral side with respect to the band saw 30 and a guide roller 17b positioned on the inner peripheral side, and circulates while pressing the band saw 30 between the guide rollers 17a and 17b. . Further, a guide bearing (not shown) is provided at a portion adjacent to the guide rollers 17 a and 17 b and on the end opposite to the cutting edge of the band saw 30. The guide rollers 17 a, 17 guide rollers 17 a, 17 b and guide bearings are fixed to the saw wheel base 5 by a guide holder 19. Here, the magnet unit 40 has a portion S between the band saw guide 7 and the contact point of the drive saw wheel 2 (the point where the rotating band saw 30 contacts the outer periphery of the drive saw wheel 2; the position shown in FIG. 5). Is provided. It is preferable that the magnet unit 40 is disposed at a revolving position where the distance from the band saw guide 7 is within S1 (= 1/2). As described above, in the present embodiment, the magnetic powder generated by the cutting operation is within the range S between the one saw wheel (driving saw wheel 2) and the band saw guide 7 located on the downstream side in the circumferential direction of the band saw 30. Although the magnet for attracting | sucking was provided, you may make it provide the further magnet in another location. In that case, a second magnet may be provided in the vicinity of the region 38 between the other saw wheel (driven saw wheel 3) located downstream in the circumferential direction of the band saw 30 and the point of contact of the band saw guide 7. . The second magnet may be provided on the saw wheel base 5 or may be provided on the saw wheel cover 20 side.

  Next, the attachment method of the magnet unit 40 is demonstrated using FIG. FIG. 6 is a single view of the back side of the saw wheel cover 20, showing the inside facing the saw blade. The saw wheel cover 20 is a cover that is opened and closed when the band saw 30 is attached and detached, and is attached to cover the openings of the saw wheel bases 4 and 5 when the portable band saw machine 1 is used. The saw wheel cover 20 is manufactured by metal press molding or integral molding of synthetic resin or the like, and includes circular portions 20a and 20b that cover one saw wheel and a connecting portion 20c that connects them. Hinges 22 a and 22 b are provided on the upper part of the saw wheel cover 20, and are pivotally supported with respect to the housing 6. Claw portions 21 a and 21 b for hooking the saw wheel cover 20 to the saw wheel bases 4 and 5 are formed below the saw wheel cover 20. Here, the magnet unit 40 is provided on the outer peripheral side of the circular portion 20 a of the saw wheel cover 20, on the downstream side in the circumferential direction of the band saw 30, in the vicinity of the claw portion 21 a. As described above, since the magnet unit 40 is mounted not on the saw wheel base 4 side but on the saw wheel cover 20, the modification point of the portable band saw machine 1 required for realizing the present embodiment is as follows. Only the saw wheel cover 20 is required, and this embodiment can be easily realized and the cost required for the realization can be greatly reduced.

  FIG. 7 is an enlarged view of a main part in the vicinity of the magnet unit 40 of FIG. In this embodiment, the permanent magnet 42 is used as the magnetic force generating means in the magnet unit 40. Since the permanent magnet 42 does not require electric power, the permanent magnet 42 can be mounted at any position as long as the problem of the space for mounting and the mounting angle are solved. The permanent magnet 42 of this embodiment is held by a magnet holder 41 made of a magnetic material such as iron, and a resin plate 43 made of a non-magnetic material is disposed on the side facing the band saw 30. FIG. 8 shows a cross section taken along the line CC in FIG. The magnet holder 41 has a case shape and is fixed to the saw wheel cover 20. This fixing method can be fixed by a known method such as adhesion, welding, or screwing. A hole is formed in a part of the permanent magnet 42, and the permanent magnet 42 is held so as not to fall out of the magnet holder 41 by a screw 44 provided through a screw hole formed in a part of the magnet holder 41. . A resin plate 43 is disposed on the side of the band saw 30 when viewed from the permanent magnet 42. The resin plate 43 is sandwiched between the magnet holders 41. However, this fixing method is arbitrary, and the resin plate 43 may be configured so as to be easily attached to and detached from the magnet holder 41, or may be fixed so as not to be attached or detached. .

  FIG. 9 is a development view of the magnet unit 40 of FIG. A magnet unit 40 is provided on a plane portion on the outer peripheral side of the circular portion 20 a of the saw wheel cover 20. The magnet unit 40 includes a permanent magnet 42 fixed to a magnet holder 41 and a resin plate 43. The magnet holder 41 is manufactured by pressing a ferrous magnetic metal, for example, an iron plate, and functions as a magnet mounting box. . A screw hole 41a for screwing a screw 44 (see FIG. 6) to be inserted into the hole 42a of the permanent magnet 42 is formed in the magnet holder 41, and the permanent magnet 42 is detachably mounted. In addition, although the material of the magnet holder 41 is good also as resin, since the magnet holder 41 itself becomes a surface in that case, the resin plate is unnecessary. Here, the resin plate 43 is provided to prevent the iron powder from adhering directly to the permanent magnet 42 so that the iron powder or the like adheres to the resin plate 43 so that the metal powder can be easily cleaned. This is so that it can be removed. When the surface of the resin plate 43 is filled with the adsorbed chips, the chips can be removed by opening the saw wheel cover 20, loosening the screws 44, and removing the permanent magnet 42 from the magnet holder 41. Alternatively, the chips can be removed by cleaning the resin plate surface with a brush or the like. Thus, if a part or all of the permanent magnet 42 is covered with a nonmagnetic material, the workability when the operator removes the iron powder adsorbed by the magnetic force of the permanent magnet 42 is greatly improved.

  FIG. 10 is a view for explaining the positional relationship between the magnet unit 40 and the band saw 30. The band saw 30 has a thickness (saw thickness) T and a width (band width) W, and the cutting edge direction is closer to the magnet unit 40, that is, the cutting edge direction side shown in FIG. The position where the magnet unit 40 is provided may be such that part or all of the magnet unit 40 is located within a range of ± 90 ° from the edge point when viewed in a plane perpendicular to the circumferential direction of the band saw (here, 0 ° is the cutting edge direction). Further, the position where the magnet unit 40 is provided is preferably separated from the band saw 30 by an appropriate distance, and the distance is a part of the magnet unit 40 within a predetermined distance (within a radius of 2 W, preferably within a radius W) from the cutting edge. Alternatively, all may be positioned, but the distance may be set according to the strength of the magnetic force of the permanent magnet 42 and the mounting position. In the present embodiment, the magnet unit 40 is provided within a range of −90 ° from the cutting edge point of the band saw 30, that is, to be located on the drive saw wheel 2 side from the cutting edge point of the band saw 30, thereby generating at the time of cutting. Since the chip to be absorbed is attracted to the permanent magnet 42 before entering the contact surface of the drive saw wheel 2 and the band saw 30, the rubber can be prevented from being damaged or torn without entering between the drive saw wheel 2 and the band saw 30. It can effectively prevent the band saw from being damaged and slipping. As a result, workability is improved and the life of the band saw 30 can be greatly improved. Portable band saw machines that do not have a base for holding the workpiece are used in various work forms such as upward work, etc., but by adopting the configuration as described above, the band saw machine is not enlarged. And it can suppress suitably that not only the operation | work form but a chip enters between a band saw and a saw wheel. Further, in the present embodiment, the magnet unit 40 is provided on the saw wheel cover 20, but it can also be mounted on the saw wheel base 4 side, and a dotted line position 46 can be considered as a probable mounting position candidate in that case.

  FIG. 11 is a view showing the saw wheel cover 20 and the magnet unit 50 of the portable band saw machine according to the second embodiment of the present invention. The shape of the saw wheel cover 20 is the same as that of the first embodiment, and the magnet unit 50 provided therein is different. However, the size and mounting position of the magnet unit 50 are substantially the same as those of the first embodiment. In other words, between the first saw wheel and the second saw wheel, one of the saw wheels (here, the drive saw wheel side) located on the downstream side in the circumferential direction of the band saw in the opening 32 and the opening 32 is cut. A magnet unit 50 for adsorbing magnetic powder generated by work is provided.

  FIG. 12 is an enlarged view of a main part in the vicinity of the magnet unit 40 of FIG. The magnet unit 50 includes a permanent magnet 52 covered with a magnet holder 51 that is a case made of synthetic resin. The magnet holder 51 is a substantially rectangular parallelepiped housing in which only one of the six surfaces is open, and a permanent magnet 52 is attached to the opening (from the left to the right in the figure as viewed in FIG. 12). The permanent magnet 52 is provided with a hole (not shown), and the tip of a screw 54 screwed into a screw hole (not shown) formed in the magnet holder 51 is inserted into the hole of the permanent magnet 52. The permanent magnet 52 is held so as not to fall out of the magnet holder 51. One side of the outer surface of the housing of the magnet holder 51 is fixed to the saw wheel cover 20, and the fixing method may be fixed by a known method such as adhesive, double-sided tape, and screwing. The permanent magnet 52 can be easily removed from the magnet holder 51 by removing the screw 54.

  13 is a cross-sectional view taken along the line DD in FIG. In the second embodiment, since the magnet holder 51 is made of resin, the magnetic powder attracted by the permanent magnet 52 is attracted to the outer peripheral surface of the magnet holder 51. However, since the magnet holder 51 is a non-magnetic material, cleaning is performed. In this case, the metal powder can be easily removed. In the second embodiment, since the thickness d of the magnet holder 51 is smaller than that of the first embodiment, the necessary mounting space is small, and the degree of freedom of the mounting position is greatly improved.

  FIG. 14 is a rear view of a portable band saw machine according to a third embodiment of the present invention. The third embodiment is characterized in that an electromagnet unit 60 using an electromagnet as a magnetic source instead of a permanent magnet is used. By using an electromagnet, a magnetic force can be arbitrarily generated, and the timing at which the magnetic force is generated or extinguished, the strength of the magnetic field, and the like can be electrically controlled. The position where the electromagnet is provided may be a predetermined distance from the cutting edge as shown in FIG. 10 (within a radius of 2 W for an electromagnet). When an electromagnet is used, it is necessary to arrange a power line (not shown) for supplying electric power. Therefore, the saw wheel base is not the detachable saw wheel cover 20 side on which a device requiring a power source is not mounted. It is more convenient in terms of wiring to provide it on the 4th side. The electromagnet can be turned on or off, for example, by interlocking with the trigger switch 12, but a dedicated switch for starting the electromagnet is provided in the housing 6 located between the saw wheel from the rear of the band saw guide 7, and this switch is turned on. In this case, power may be supplied to the electromagnet.

  FIG. 15 is a cross-sectional view of the main part in the vicinity of the electromagnet unit 60 of the portable band saw machine according to the third embodiment of the present invention. Compared to the magnet unit 40 shown in FIG. 10, the electromagnet unit 60 is provided in the vicinity of the side opposite to the cutting edge of the band saw 30 (on the side opposite to the cutting edge). This is because the electromagnet unit 60 is provided not on the saw wheel cover 20 side but on the saw wheel base 4 from the viewpoint of ease of electric wiring. The attachment position is the same as in the first and second embodiments, and is the downstream side (traveling side) of the band saw 30 as viewed from the opening 32 (see FIG. 2). 2) and the guide plate 10.

  FIG. 16 is an electric circuit diagram of a portable band saw machine according to the third embodiment of the present invention. In this embodiment, an example of a cordless type portable band saw using a detachable battery 71 as a power source for driving a motor is described. As the battery 71, a battery pack using a nickel-cadmium battery or a lithium ion battery widely used in electric tools may be used. A cordless portable band saw is realized by attaching the battery pack to a part of the housing 6. it can. The motor 14 is a brushless DC motor, and the semiconductor switching element is driven by a controller 70 having a microcomputer using an inverter circuit 72 realized by the semiconductor switching element. The controller 70 receives the output of the trigger switch 12 and the output signal of the speed adjusting means 73 adjusted by the speed setting knob 23. The coil of the electromagnet 61 is energized by the controller 70, and the generation (ON) and extinguishing (OFF) of the magnetic field are arbitrarily controlled. The on / off control of the electromagnet 61 is a method of interlocking with the on / off of the trigger switch 12. The electromagnet is on when the trigger switch 12 is on in correspondence with the trigger switch 12, and the electromagnet is delayed when the trigger switch 12 is off. Various control methods are possible, such as a method of turning off or a method in which a dedicated switch 65 for the electromagnet 61 is provided so that an operator can arbitrarily set the electromagnet 61 on and off. When the controller 70 controls on / off of the electromagnet 61, the switch 65 shown in FIG. 16 can be omitted.

  As mentioned above, although this invention was demonstrated based on the Example, this invention is not limited to the above-mentioned Example, A various change is possible within the range which does not deviate from the meaning. For example, in this embodiment, the magnet units 40 and 50 and the electromagnet unit 60 are provided between the contact point of the drive saw wheel 2 and the guide plate 10 or the band saw guide 7. You may make it provide also in the area | region 38 near between the edge parts of an opening part. The mechanism for sucking the generated chips with a magnet may be applied not only to a portable band saw machine but also to a permanent band saw machine. In that case, it is preferable to use an electromagnet.

DESCRIPTION OF SYMBOLS 1 Portable band saw machine 2 Drive saw wheel (first saw wheel) 3 Driven saw wheel (second saw wheel)
4 saw wheel base 4a screw groove 4b guide groove 5 saw wheel base 6 housing 7 band saw guides 7a and 7b guide roller 8 guide bearing 9 guide holder 10 guide plate 10a notch 12 trigger switch 13 handle 14 motor 15 auxiliary handle 16 power supply Cord 17 Band saw guide 17a, 17b Guide roller 19 Guide holder 20 Saw wheel cover 20a Circular portion 20c Connecting portion 21a, 21b Claw portion 22a, 22b Hinge 23 Speed setting knob 24 Illumination device 25 Light switch 26 Tension lever 27, 28 Sprocket 29 Chain 30 Band Saw 31 Rotating Direction 32 Opening 36 Screw 37 Cutting Direction 40 Magnet Unit 41 Magnet Holder 41a Screw Hole 42 Permanent Magnet 42a Hole 43 Resin Plate 44 Screw 50 Magnet Unit 51 Magnet Rudder 52 Permanent magnet 54 Screw 60 Electromagnet unit 61 Electromagnet 65 Switch 70 Controller 71 Battery 72 Inverter circuit 73 Speed adjusting means 101 Portable band saw 104, 105 Saw wheel base 106 Housing 110 Guide plate 112 Switch 113 Handle portion 115 Auxiliary handle 200 Covered Cutting material

Claims (9)

A first saw wheel and a second saw wheel over which an annular band saw is bridged;
A motor for rotating the first saw wheel;
A housing for supporting the first saw wheel, the second saw wheel, and the motor;
The housing has an opening that exposes the band saw between the first saw wheel and the second saw wheel, and a band saw machine that performs a cutting operation with the band saw located in the opening,
Magnetic powder generated by a cutting operation between any one of the first saw wheel and the second saw wheel located downstream of the band saw in the circumferential direction of the band saw and the opening. A band saw machine provided with a magnet for adsorbing. A band saw that holds the band saw so as to twist at a predetermined angle with respect to the outer circumferential guide surfaces of the first saw wheel and the second saw wheel on the upstream side and the downstream side in the circumferential direction of the band saw in the opening. A guide,
2. The magnet according to claim 1, wherein the magnet is provided between the band saw guide located on the downstream side and a contact point of the adjacent saw wheel, and near the side surface or the rear surface of the band saw. The band saw machine described. A removable saw wheel cover that covers the saw wheel is attached to the housing,
The band saw machine according to claim 2, wherein the magnet is fixed to the housing or the saw wheel cover in a state of being housed in a resin or non-magnetic case.   4. The band saw according to claim 3, wherein when the band width of the band saw is W, the magnet is arranged so that a part or all of the magnet is located within a distance W from a cutting edge of the band saw. Board.   A guide plate having a guide surface orthogonal to the circumferential direction of the band saw is provided between the band saw guide located on the downstream side in the circumferential direction of the band saw in the opening of the housing and the opening. The band saw machine according to claim 3 or 4.   The band saw guide has two sets of guide rollers that rotate while pressing the outer peripheral surface and the inner peripheral surface of the band saw, and a guide bearing that holds an end of the band saw opposite to the cutting edge. Item 6. The band saw machine according to item 5.   The band saw according to claim 6, wherein the magnet is a permanent magnet and is detachably fixed to the saw wheel cover in a state of being attached to a metal magnet holder.   The band saw machine according to any one of claims 1 to 7, wherein a detachable battery for supplying electric power to the motor is attached to the housing, and the motor is driven by electric power of the battery. .   The band saw machine according to any one of claims 1 to 8, wherein the magnet is an electromagnet, and power supply to the electromagnet is controlled in conjunction with power supply to the motor.

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