WO2017094413A1

WO2017094413A1 - Band saw

Info

Publication number: WO2017094413A1
Application number: PCT/JP2016/082062
Authority: WO
Inventors: 鈴木　康之; 五史小川; 正金澤
Original assignee: 日立工機株式会社
Priority date: 2015-11-30
Filing date: 2016-10-28
Publication date: 2017-06-08

Abstract

Provided is a band saw in which a plastic housing is used in order to reduce the weight of a device, and in which the likelihood of a blade dislodging from a guide roller is reduced. A first guide roller mechanism 30 and a second guide roller mechanism 40 have a pair of cylindrical guide rollers that rotate while being in contact, respectively, with the outer peripheral side and the inner peripheral side of the blade 20. The tip sides of the guide rollers 31, 41 and the guide rollers corresponding to the guide rollers 31, 41 are inclined with respect to the direction in which the blade runs. As a result, a force acts on the blade in the direction opposite that in which the blade is dislodged, making it possible to stabilize the position in which the blade is running.

Description

Band saw

The present invention relates to a band saw that performs processing such as cutting with a band saw stretched on a saw wheel, and more particularly, to a band saw traveling position adjusting mechanism that is improved so as to stabilize the position of the band saw.

Band saws (band saw machines) that use an electric motor as a drive source are widely used. For example, in Patent Document 1, a driving saw wheel is driven by rotating a motor according to an operation of a trigger switch by an operator, and an endless band saw stretched between the outer periphery of the driving saw wheel and the driven saw wheel is rotated. A band saw for cutting a material to be cut such as an iron pipe is disclosed. When performing a cutting operation with a band saw, the operator grasps the handle portion with his hand and moves the band saw to the upper side of the workpiece to position the band saw so that the surface direction of the band saw coincides with the planned cutting surface. Then, when the operator rotates the band saw by pulling the trigger and moves the band saw downward toward the material to be cut in this state, the material to be cut is cut. When the cutting operation is completed, the motor stops when the worker releases the trigger.

JP 2012-139753 A

In the band saw shown in Patent Document 1, a base member that holds a driving saw wheel and a driven saw wheel and a connecting portion that connects the two base members are made of metal. On the other hand, in recent portable band saws, the use of resin for metal parts has been promoted in order to further reduce the weight. In examining the realization of plasticization of the base member and the housing part for holding the driving saw wheel and the driven saw wheel, the band saw is guided by a slight deflection or deformation when the resin base member is used. We faced the phenomenon of shifting from the proper position held by the roller. As a result of verification by the inventors, the phenomenon that the band saw is displaced is guided by twisting the band saw stretched between the two saw wheels by a guide roller, so that it is always subjected not only to bending by rotation but also torsion (shear). It was found that a strong force was applied to the housing and the base member, the guide roller mechanism fixed to the resin portion was slightly inclined, and the guide roller was not parallel to the traveling direction of the band saw. By shifting the band saw from the proper position, the holding force of the guide roller against the band saw is not uniform, and the band saw may be damaged at an early stage. There is a risk that the work will be different from the intention of the worker.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a band saw that can stabilize the traveling of the band saw and improve the reliability and the life. Another object of the present invention is to provide a band saw that uses a resin housing to reduce the weight of the device and that the band saw is less likely to be displaced from its proper position.

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 driving saw wheel and a driven saw wheel, a motor that rotates the driving saw wheel, a first saw wheel base that rotatably supports the driving saw wheel, and a driven saw wheel that can rotate. A second saw wheel base supported by the first saw wheel base, a band saw stretched between the outer circumferences of the first saw wheel base and the second saw wheel base, and the first saw wheel base and the second saw wheel base spaced apart. An opening for exposing a part of the band saw, a first guide roller mechanism held on the first saw wheel base for guiding the running of the band saw, and a second guide held on the second saw wheel base for guiding the band saw running In the band saw having the guide roller mechanism, each of the first guide roller mechanism and the second guide roller mechanism has a pair of cylindrical guide rollers that rotate while contacting the outer peripheral side and the inner peripheral side of the band saw, The rotation axis of the guide roller is almost perpendicular to the traveling direction of the band saw. Arranged so that, and to tilt the pair of guide rollers with respect to the running direction of the band saw. The guide roller to be tilted is inclined only at the same angle or at a different angle, regardless of whether it is only on the first guide roller mechanism side or only on the second guide roller mechanism side. Anyway.

According to another aspect of the present invention, the first saw wheel base and / or the second saw wheel base is made of resin, and the guide roller cantileveres two rotating shafts extending in parallel. Each of the first saw wheel base and the second saw wheel base is screwed by the mounting member. Further, in at least one of the first guide roller mechanism and the second guide roller mechanism, the open end side of the cantilevered rotating shaft may be inclined so as to face the traveling direction of the band saw.

According to still another aspect of the present invention, a connecting portion that connects the first saw wheel base and the second saw wheel base at a portion adjacent to the opening is provided, and the first saw wheel base and the second saw wheel base are provided. The connecting portion was manufactured integrally with a synthetic resin molded product. Further, the inclination of the guide roller mechanism can be realized by shifting the position of the screw hole of the mounting member.

According to the present invention, since the guide rollers of the first and second guide roller mechanisms are inclined toward the traveling direction side of the band saw, a force can be applied to push the band saw in the direction opposite to the blade edge by the guide roller. Can be effectively prevented from shifting, and the traveling position of the band saw is stabilized. In particular, when a so-called resin frame is used in which the first saw wheel base and the second saw wheel base are made of resin, even if the resin frame is warped or deformed, the rotation axis of the guide roller is the traveling direction of the band saw. Since it is inclined to the side, the band saw can be pushed down in a direction that does not shift.

It is a front view of the band saw 1 which concerns on the Example of this invention. It is a figure which shows the figure which opened the cover (not shown) of the band saw 1 of FIG. 1 and was seen from the back side. FIG. 3 is a partial enlarged view for explaining a fixing state of the first guide roller mechanism 30 and the second guide roller mechanism 40 in FIG. 2 (No. 1). FIG. 3 is a partially enlarged view for explaining a fixing state of the first guide roller mechanism 30 and the second guide roller mechanism 40 in FIG. 2 (part 2). It is a schematic diagram for demonstrating the inclination of a guide roller. It is a figure for demonstrating an example of the method of inclining a guide roller.

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 vertical and horizontal directions are directions shown in the drawing.

FIG. 1 is a front view of a band saw 1 according to an embodiment of the present invention. The band saw 1 is an electric tool that is driven by a battery 51 and cuts a material to be cut by a band saw 20 that is a tip tool. When the operator operates the trigger switch 17 while pressing the off-lock release button 18 in a state where the battery 51 is mounted on the battery mounting portion, a motor (not shown) disposed in the motor cover 15 rotates. A band saw 1 is provided with a first saw wheel base (drive saw wheel base) 3 for accommodating a drive saw wheel (not shown) on one side, and a driven saw wheel (not shown) on the other side. A second saw wheel base (driven saw wheel base) 4 for housing is provided. The first saw wheel base 3 and the second saw wheel base 4 constitute part of a broadly defined housing (housing) of the band saw 1 and also serve as a frame for pivotally supporting the saw wheel. The first saw wheel base 3 and the second saw wheel base 4 are spaced apart from each other by a predetermined distance, and an opening 10 is formed between them. The saw wheel base 3 and the second saw wheel base 4 are connected. The opening 10 has a substantially square shape, and the exposed portion of the band saw 20 in the opening 10 is a cuttable portion (cutting length).

The first saw wheel base 3 and the second saw wheel base 4 are manufactured together with the connecting portion 5 by integral molding of resin. An annular band saw 20 is bridged between the first saw wheel base 3 and the second saw wheel base 4, and a part of the band saw 20 is exposed at the opening 10. The motor rotates the drive saw wheel by a rotation transmission mechanism (not shown). The drive saw wheel that is driven to rotate transmits the rotational force to the band saw 20 and rotates the band saw 20 in the direction of the arrow 25a. The driven saw wheel is a circular pulley that is rotated with respect to the drive saw wheel by a rotating band saw 20, and the cutting edge side 20 a of an endless band saw (band saw blade) 8 stretched between them is an iron pipe. It can cut | disconnect by pressing against material to be cut | disconnected (not shown).

When cutting the material to be cut with the band saw 1, the band saw 20 rotates in the rotation direction (arrow 25a), and the material to be cut is pushed in the same direction as the rotation direction by this rotation. The guide plate 21 that prevents the material to be cut from moving in the operating direction of the band saw 20 is provided on the side where the guide plate 21 is pressed (the first saw wheel base 3 side). The guide plate 21 has a shape and size set in accordance with the size and shape of the material to be cut or a space with the material to be cut (existing pipe or the like) and the like, and is located in the long hole 21b. By loosening the two screws 22, the movement can be adjusted in the direction orthogonal to the rotation direction (arrow 25 a). By tightening the two screws 22, the tip end 21 a can be fixed at an arbitrary position.

The second saw wheel base 4 is provided with a tension lever 23 for attaching or removing the band saw 20 by adjusting the position of the driven saw wheel and adjusting the tension. The tension lever 23 can be rotated about 135 degrees around the rotation shaft 23a, and the tension lever 23 is rotated about 90 degrees clockwise from the state shown in FIG. If you do, the tension will be loosened. A side handle attachment portion 24 for attaching a side handle (not shown) is provided near the upper side of the second saw wheel base 4.

A handle portion 6 is provided so as to connect the upper portions of the first saw wheel base 3 and the second saw wheel base 4. The handle portion 6 has a donut shape, a grip portion 6a for an operator to grip is formed in the upper portion, a battery attachment portion 6b for mounting the battery 51 is formed in the vicinity of the left side, and the vicinity of the lower side The first saw wheel base 3 and the second saw wheel base 4 are connected, and a connecting portion 6c in which the band saw 20 travels is formed in the internal space. The connecting portion 6c is joined to the other connecting portion 5 (details will be described later with reference to FIG. 2). The battery 51 is detachable from the handle portion 6 and is configured to be detached from the handle portion 6 by moving in a direction away from the second saw wheel base 4 and intersecting the longitudinal direction of the gripping portion 6a. Is done. When removing the battery 51, the latch 52 is moved while being pushed. A trigger switch 17 is provided below the grip 6a, and an off-lock release button 18 that allows the trigger switch 17 to be operated is provided above the trigger switch 17. On the left side of the connecting portion 6 c of the handle portion 6, an LED light 19 for irradiating the vicinity of the portion cut by the band saw 20 is provided.

A synthetic resin opening / closing type cover (not shown) is provided on the back side of the first saw wheel base 3 and the second saw wheel base 4 of the band saw 1 (the part not visible in FIG. 1). The cover is of a swing type, and is provided with

rotating mechanisms

7a and 7b (described later in FIG. 2) on the upper side of the first saw wheel base 3 and the second saw wheel base 4, and the first saw wheel base 3 A latch portion 8a that engages with a locking portion (not shown) of the cover is provided at a lower end portion of the second saw wheel, and a latch that engages with a locking portion (not shown) of the cover at the lower end portion of the second saw wheel base 4. A portion 8b is provided.

FIG. 2 is a view showing the band saw 1 shown in FIG. 1 when the cover (not shown) is opened and seen from the back side, and shows a state where the back cover and handle portion 6 (not shown) are also removed. Here, the state is shown in which the band saw 1 is turned upside down so that the opening 10 is on the upper side and the connecting part 5 is on the lower side. The first saw wheel base 3, the second saw wheel base 4 and the connecting portion 5 are integrally manufactured by a molded product of synthetic resin such as plastic. The surface side (surface visible from the outside as shown in FIG. 1) of the integrally molded component (the first saw wheel base 3, the second saw wheel base 4, and the connecting portion 5) is formed into a smooth plane or curved surface. However, a large number of reinforcing ribs (3a, 4a) are formed on the back side (inner side) shown in FIG. 2 in order to increase the rigidity while reducing the weight. A large number of truss-structured ribs 3a are formed in the first saw wheel base 3, and a substantially triangular thin plate portion 3b is formed between the ribs 3a. Similarly, a large number of truss-structured ribs 4a are formed on the second saw wheel base 4, and a substantially triangular thin plate portion 4b is formed between the ribs 4a. The shape of the region (thin plate portion) surrounded by the

ribs

3a and 4a is not limited to a triangle, and ribs that face various directions are formed in the vicinity of the driving saw wheel 13 and the driven saw wheel 14 so as to form various patterns. Is formed.

The connecting portion 5 is regularly formed with diagonal lattice-like ribs 5a. A region surrounded by the ribs 5a is a rhomboid thin plate portion 5b. Since the connecting portion 5 needs to have higher strength against twisting than the first saw wheel base 3 and the second saw wheel base 4, the thickness of the rib 5 a is increased and the rib height is increased. It is better to increase the strength sufficiently. Below the connecting portion 5, a linear groove-shaped traveling passage 5 c is formed for the band saw 20 to go around. Since the travel path 5c is covered with a cover (not shown), the band saw 20 travels in a state where it is not exposed to the outside in the travel path 5c. Mounting bases 9a to 9c for screwing the handle portion 6 are provided outside the connection portion 5 in the vicinity of the traveling passage 5c. The mounting bases 9a to 9c are formed with a screw hole in the center, and are integrated with the first saw wheel base 3, the second saw wheel base 4 and the connecting portion 5 in the same manner as the

rotation mechanisms

7a and 7b. Manufactured by molding. Note that the pattern (lattice pattern) or the like formed by the arrangement of the ribs 5a is arbitrary, and an appropriate grid-like rib is formed on the inner wall side in order to achieve the required strength. Therefore, it is preferable that the thickness of the resin does not become too thick.

On the first saw wheel base 3 side, a driving saw wheel (first saw wheel) 13 that rotates about a rotation shaft 13a is provided. The drive saw wheel 13 rotates in the direction of the mark 13b, and the band saw 20 spanning the cylindrical surface is axially extended so that the outer peripheral side becomes a cylindrical surface and both axial ends of the cylindrical surface extend radially outward. It is formed in a pulley shape that guides it so that it does not come off. The drive saw wheel 13 is manufactured by, for example, synthetic resin integral molding. The rotary shaft 13a of the drive saw wheel 13 is connected to the rotary shaft of a motor (not shown) serving as a drive source directly or via a power transmission mechanism such as a reduction mechanism (not shown). Similarly, a driven saw wheel (second saw wheel) 14 that rotates about the rotation shaft 14a is provided on the second saw wheel base 4 side. The driven saw wheel 14 has substantially the same structure and shape as the drive saw wheel 13, and an annular band saw 20 is bridged on the outer peripheral surface. A power source is not connected to the driven saw wheel 14, and the driven saw wheel 14 rotates depending on the band saw 20 that is driven by the rotation of the drive saw wheel 13. In the band saw 1, the band saw 20 is driven in a state in which the band saw 1 is stretched with an appropriate tension. Therefore, of the two saw wheels for guiding the band saw 20, a tension applying mechanism (not visible because it is on the back side of the driven saw wheel 14 in FIG. 2) is connected to the driven saw wheel 14 side that is not driven by the motor.

The band saw 20 is bridged between the drive saw wheel 13 and the driven saw wheel 14, and is opened to the outside on one side of the path (on the way from the driven saw wheel 14 to the drive saw wheel 13). 10 and the other side of the path (on the way from the driving saw wheel 13 to the driven saw wheel 14), it passes through the inner space (traveling path 5c) of the connecting portion 5 and the handle portion 6 (see FIG. 1). A second guide roller mechanism for holding the band saw 20 to be twisted so as to have a predetermined angle with respect to the outer circumferential guide surface of the second saw wheel on the upstream side in the circumferential direction of the band saw 20 exposed at the opening 10. 40 is provided. In addition, on the downstream side in the circumferential direction of the band saw 20 exposed at the opening 10, a first for twisting the band saw twisted at a predetermined angle so as to return it to coincide with the outer peripheral surface of the drive saw wheel 13. A guide roller mechanism 30 is provided.

The first guide roller mechanism 30 provided on the side close to the drive saw wheel 13 includes a guide roller 31 located on the inner peripheral side with respect to the band saw 20 and a guide roller 32 located on the outer peripheral side, and these guide rollers. The band saw 20 circulates between 31 and 32 while being pressed. In addition, a guide bearing 33 serving as a third roller is provided so as to be in contact with an end portion (opposite blade edge side 20b) of the band saw 20 that is adjacent to the

guide rollers

31 and 32 and opposite to the blade edge side 20a. The guide bearing 33 is a cylindrical roller having a rotation shaft extending in a direction orthogonal to the surface of the band saw 20, and prevents the band saw 20 from being displaced by pressing the side 20 b opposite to the blade edge 20.

The

guide rollers

31 and 32 are metal rolling bearings whose outer peripheral surfaces are cylindrical, and for example, cylindrical ball bearings can be used. Here, in order to make the length in the axial direction match the width of the band saw 20, two cylindrical ball bearings are stacked in the axial direction. Therefore, a joining portion such as a groove can be visually recognized near the axial center of the

guide rollers

31 and 32.

Screws

37 and 38 pass through the inner rings of the

guide rollers

31 and 32, and the

screws

37 and 38 serving as rotation shafts are fixed so as to extend in parallel with the mounting base 34 serving as a mounting member. Therefore, the rotation shafts of the

guide rollers

31 and 32 are fixed ends fixed to the mounting base 34 on the side close to the first saw wheel base 3, but are open ends that are not fixed on the far side. Thus, since one side of the rotating shaft of the

guide rollers

31 and 32 is an open end, and the outer peripheral surface of the

guide rollers

31 and 32 is disposed with a gap necessary for interposing the band saw 20, the band saw 20 is It can be attached so as to slide between the

guide rollers

31 and 32 from one side in the axial direction.

The mounting base 34 is made of metal and secures a function of fixing the

screws

37 and 38 for supporting the

guide rollers

31 and 32 and an accommodation space for accommodating the guide bearing 33, and a rotation shaft (not shown) of the guide bearing 33 is provided. It has a function of fixing and holding the guide bearing 33 rotatably, and a function of an attachment base for fixing them to the first saw wheel base 3. As shown in FIG. 2, the mounting base is formed with an inverted L-shaped arm portion, and two

screw holes

34a and 34b (described later in FIG. 3) are formed in the vicinity of the tip of the arm portion. The mounting base 34 is screwed to the first saw wheel base 3 by two

screws

35 and 36.

A second guide roller mechanism 40 is provided on the side close to the driven saw wheel 14. The configuration of the second guide roller mechanism 40 is substantially the same as the configuration of the first guide roller mechanism 30 and includes a guide roller 41 positioned on the inner peripheral side with respect to the band saw 20 and a guide roller 42 positioned on the outer peripheral side. Is done. In addition, a guide bearing 43 serving as a third roller is provided so as to be in contact with the end portion (the anti-blade edge side 20 b) that is adjacent to the

guide rollers

41 and 42 and is opposite to the blade edge side 20 a of the band saw 20. The

guide rollers

41 and 42 can use the same components as the

guide rollers

31 and 32, and similarly, the guide bearing 43 can use the same components as the guide bearing 33. The inner rings of the

guide rollers

41 and 42 are cantilevered to a mounting base 44 as a mounting member by

screws

47 and 48. The rotation shafts of the

guide rollers

41 and 42 are fixed ends that are fixed to the mounting base 44 on the side close to the second saw wheel base 4, but are open ends that are not fixed on the far side. The mounting base 44 is made of metal, and when viewed as shown in FIG. 2, an inverted L-shaped arm portion is formed, and two screw holes 44a and 44b (described later in FIG. 3) are formed near the tip of the arm portion. Is done. The mounting base 44 is fixed to the second saw wheel base 4 by two

screws

45 and 46.

When the trigger switch 17 (see FIG. 1) is operated, a motor (not shown) disposed in the motor cover 15 rotates, and the rotational force is transmitted to the power transmission mechanism to drive the drive saw wheel 13. When the drive saw wheel 13 rotates, the band saw 20 travels, and the driven saw wheel 14 that is pivotally supported on the second saw wheel base 4 side is driven and rotated according to the travel. The band saw 20 is used over two saw wheels (pulleys), and a saw blade (not shown) is cut on one side (blade edge side 20a) of an annular and strip-shaped steel plate. A saw wheel rubber (not shown) is fitted on the outer peripheral surfaces of the driving saw wheel 13 and the driven saw wheel 14 so that the band saw 20 contacts the outer peripheral surface of the driving saw wheel or the driven saw wheel via the saw wheel rubber. To do. Each of the first guide roller mechanism 30 (see FIG. 1) and the second guide roller mechanism 40 has two sets of guide rollers, and is inclined by a predetermined angle with respect to the outer peripheral surface of the drive saw wheel 13 or the driven saw wheel 14 ( The band saw 20 is twisted and held so that it is less than 60 degrees). The angle of the twisted band saw 20 is substantially the same as the upright direction of the band saw 1. As a result, the exposed band saw 20 in the opening 10 can be pressed almost perpendicularly to the material to be cut. The first guide roller mechanism 30 returns the band saw 20 twisted obliquely to the original angle and guides it to the outer peripheral surface of the drive saw wheel 13. Further, since the guide rollers of the first guide roller mechanism 30 and the second guide roller mechanism 40 are in contact with the traveling band saw 20, the

guide rollers

31, 32 on the drive saw wheel 13 side when the band saw 20 is traveling, The

guide rollers

41 and 42 on the driven saw wheel 14 side rotate.

FIG. 3 is a partially enlarged view for explaining a fixing state of the first guide roller mechanism 30 and the second guide roller mechanism 40 of FIG. In this embodiment, the

guide rollers

41 and 42 are fixed so that the central axes of the

guide rollers

41 and 42 are inclined toward the traveling direction side of the band saw 20. Similarly, the

guide rollers

31 and 32 were fixed so that the central axes of the

guide rollers

31 and 32 were inclined toward the traveling direction of the band saw 20. As described above, the extending direction (tangential direction) of the rotation surface of the outer peripheral surface of the guide roller and the longitudinal direction of the band saw 20 are slightly shifted from each other, so that the band saw 20 moves in the direction opposite to the cutting edge side 20a. Works. Specifically, when each guide roller rotated by the traveling of the band saw 20 rotates about a rotation axis inclined with respect to the traveling direction of the band saw 20, the band saw 20 is guided in the rotating direction of the contact guide roller. Therefore, the band saw 20 receives a force that moves in the direction opposite to the cutting edge side 20a (counter cutting edge side 20b). And it contacts the

guide bearings

33 and 43 which are the third rollers, and maintains the proper position while restricting the movement in the direction opposite to the blade edge side 20a. Therefore, it is possible to suppress the band saw 20 from shifting from the two

guide rollers

41 and 42 to the open end side, and similarly to prevent the band saw 20 from shifting from the two

guide rollers

31 and 32 to the open end side.

The degree to which the front end side (open end side) of the central axis of the

guide rollers

31, 32, 41, 42 is slightly inclined with respect to the direction orthogonal to the longitudinal direction of the band saw 20 is shown in side view as shown in FIG. In other words, when viewed from the normal direction of the inner peripheral surface of the band saw 20, the distance from the guide plate 21 is shifted by about 1.7 mm as shown by the two-dot chain line. Here, the width of the opening 10 (maximum cutting width) is 86 mm. The two-dot chain line is obtained by subtracting an extended virtual line (dotted line) on the upper surface of the guide roller 41 from the cross point between the band saw 20 and the central axis of the guide roller 41, and the upper end of the band saw 20 is about 1.7 mm at that point. The

guide rollers

41 and 42 were inclined so as to face downward from the position.

4 is the same view as FIG. 3, but shows a side view with the guide plate 21 removed from FIG. When viewed from the side view shown in FIG. 4, when an extended virtual line (two-dot chain line) on the upper surface of the guide roller 41 is drawn from the cross point between the band saw 20 and the central axis of the guide roller 41, 1.9 mm (relationship shown) Note that the arrow facing the left side of the central axis is written on the upper side, so that it crosses the central axis of the guide roller 41 from the upper end position of the band saw 20 to the lower side.

FIG. 5 is a schematic diagram for explaining the inclination of the guide roller 41. Here, as a representative example, a state in which the guide roller 41 is viewed from the side surface (normal direction of the back surface of the band saw 20) is shown, but the guide roller 31 has the same positional relationship. Similarly, the guide roller 42 disposed opposite to the guide roller 41 and the guide roller 32 disposed corresponding to the guide roller 31 are similarly configured so that the open end of the rotating shaft is inclined toward the traveling direction side of the band saw 20. Be placed. FIG. 5A is a view of the guide roller 41 viewed from the normal direction of the band saw 20. Here, the axis 47a of the guide roller 41 with respect to the band saw 20 is at an angle with respect to an orthogonal line 49 orthogonal to the traveling direction of the band saw 20 as viewed from the normal direction of the inner peripheral surface or outer peripheral surface of the band saw 20. It is arranged so as to be inclined by θ. Here, the inclination angle θ is defined as + in the direction in which the open end of the rotating shaft is directed toward the traveling direction side of the band saw 20. Since the guide roller 41 is inclined as described above, the longitudinal direction of the outer peripheral surface of the guide roller 41 is in contact with the oblique direction so as to have a relative angle θ with respect to the longitudinal direction of the band saw 20. A force is applied to 20 in a predetermined direction, that is, in a direction approaching the fixed side of the rotating shaft of the guide roller (direction of arrow 50). As a result, since the band saw 20 can be prevented from moving from the

guide rollers

41 and 42 to the open end side, the occurrence of the phenomenon that the band saw 20 is displaced by more than a predetermined amount can be greatly reduced.

FIG. 5B is a diagram illustrating the relationship between the set inclination angle θ of the guide roller 41 and the allowable tolerance α. The guide roller 41 is fixed by a mounting base 44 (see FIG. 2) made of steel, and the mounting base 44 is fixed to the second saw wheel base 4 made of resin by using screws 45. Since the mounting base 44 normally passes through the screw 45, the diameter is slightly larger than the maximum outer diameter of the screw 45, so the mounting base 44 is fixed to the first saw wheel base 3 or the second saw wheel base 4 with a screw. When doing so, variations (tolerances) are inevitably produced at the fixed positions. When this design tolerance is ± α, in the present embodiment, both the set inclination angle θ + α and the set inclination angle θ−α are inclined with respect to the orthogonal line 49 toward the traveling direction of the band saw 20. I tried to enter. As a result, even if variations occur due to the assembly accuracy, there is no case in which the guide roller 41 and the opposite 42 are inclined in the direction opposite to the traveling direction of the band saw 20, so that the phenomenon that the band saw 20 shifts is extremely unlikely. Become.

The inclination of the guide roller 41 described in FIG. 5 is similarly applied to the guide roller 31 side. In this case, the set inclination angle θ may be the same on the guide roller 41 side and the guide roller 31 side, or one of the set inclination angles may be increased and the other may be decreased (or 0).

Next, a method for inclining the guide roller 41 and fixing the guide roller 41 to the second saw wheel base 4 will be described with reference to FIG. There are several ways to achieve this inclination. For example, there are a method of changing the mounting angle of the screw 47 with respect to the mounting base 44, a method of changing the shape of the mounting base 44 itself, a method of changing the shape of a screw boss (not shown) on the second saw wheel base 4 side, and the like. However, in this embodiment, the position of the screw hole 44a of the mounting base 44 is slightly shifted as shown in FIG. As in the prior art, the guide roller 41 is slightly offset from the position (indicated by the dotted line 64a) when the guide roller 41 is attached so that the axis 47a of the guide roller 41 coincides with the orthogonal line 49 orthogonal to the traveling direction of the band saw 20. The screw hole 44a was opened. Although not shown here, the screw hole 44b through which the screw 46 passes is similarly offset. By shifting the positions of the screw holes 44b and 44c in this way, the assembly of the mounting base 44 to which the

guide rollers

41 and 42 and the guide bearing 43 are fixed can be obtained by using the

screws

45 and 46 as in the conventional case. The

guide rollers

41 and 42 can be easily tilted simply by fixing to the vehicle base 4.

As described above, according to the present embodiment, since the open end side of the

guide rollers

31, 32, 41, 42 is inclined to the traveling direction side of the band saw, it has a function as a band saw deviation suppressing means. A band saw in which the inner band saw is not easily displaced from its proper position has been realized. In particular, even when the housing is made of resin, a band saw that is easy to use because the band saw is difficult to shift has been realized.

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, although the portable cordless band saw has been described in the above-described embodiment, the present invention can be similarly applied to a band saw that cannot be carried or a band saw that uses an AC power source. Further, the present invention can be similarly applied to a band saw in which the housing portion is not only a resin band saw but also a metal. Further, although the position of the screw hole 44a of the mounting base is slightly shifted as a method of inclining the guide roller, the present invention is not limited to this, and can be changed to the above-described configurations that are considered as several methods for realizing the inclination. As a result, the rotation axis of the guide roller only needs to be inclined in the traveling direction with the fixed end as a fulcrum with respect to the traveling direction of the band saw 20.

DESCRIPTION OF SYMBOLS 1 ... Band saw, 3 ... First saw wheel base, 3a ... Rib, 3b ... Thin plate part, 4 ... Second saw wheel base, 4a ... Rib, 4b ... Thin plate part, 5 ... Connection part, 5a ... Rib, 5b ... Thin plate Part, 5c ... travel path, 6 ... handle part, 6a ... gripping part, 6b ... battery mounting part, 6c ... connecting part, 7a, 7b ... rotating mechanism, 8a, 8b ... latch part, 9a-9c ... mounting base, DESCRIPTION OF SYMBOLS 10 ... Opening part, 13 ... Drive saw wheel, 13a ... Rotary shaft, 13b ... Mark, 14 ... Driven saw wheel, 14a ... Rotary shaft, 15 ... Motor cover, 17 ... Trigger switch, 18 ... Off-lock release button, 19 ... LED light, 20 ... band saw, 20a ... blade edge side, 20b ... anti-blade edge side, 21 ... guide plate, 21a ... tip, 21b ... oblong hole, 22 ... screw, 23 ... tension lever, 23a ... rotating shaft, 24 ... side Handle mounting part, 25 ... Arrow, 25b ... Mark, 30 ... First guide roller mechanism, 31, 32 ... Guide roller, 33 ... Guide bearing, 34 ... Mounting base, 34a, 34b ... Screw hole, 35-38 ... Screw, 40 ... Second

guide Roller mechanism

41, 42 ... guide roller, 43 ... guide bearing, 44 ... mounting base, 44a, 44b ... screw hole, 45-48 ... screw, 47a ... axis, 49 ... orthogonal line, 51 ... battery, 52 ... latch

Claims

Drive saw wheel and driven saw wheel, motor for rotating the drive saw wheel, first saw wheel base for rotatably supporting the drive saw wheel, and second saw wheel for rotatably supporting the driven saw wheel A base saw, a band saw stretched between outer peripheries of the first saw wheel base and the second saw wheel base, the first saw wheel base and the second saw wheel base being spaced apart from each other, An opening for exposing a part, a first guide roller mechanism that is held by the first saw wheel base and guides the travel of the band saw, and is held by the second saw wheel base and guides the travel of the band saw In the band saw having the second guide roller mechanism, the first guide roller mechanism and the second guide roller mechanism each include a pair of cylindrical guide rollers that rotate while contacting the outer peripheral side and the inner peripheral side of the band saw. A rotating shaft of the guide roller Band saw, characterized in that inclined to the running direction of the band saw.
2. The band saw according to claim 1, wherein one or both of the first guide roller mechanism and the second guide roller mechanism are inclined.
At least one of the first saw wheel base and the second saw wheel base is made of resin, and the guide roller is supported by a mounting member that cantileverly supports two rotating shafts extending in parallel. The band saw according to claim 2, wherein the band saw is screwed to a vehicle base or a second saw wheel base.
The at least one of the first guide roller mechanism and the second guide roller mechanism is characterized in that the open end side of the rotating shaft that is cantilevered is inclined so as to face the traveling direction of the band saw. The listed band saw.
A connecting portion that connects the first saw wheel base and the second saw wheel base is provided at a portion adjacent to the opening, and the first saw wheel base, the second saw wheel base, and the connecting portion are made of synthetic resin. The band saw according to claim 4, wherein the band saw is manufactured integrally with the molded product.
The band saw according to claim 5, wherein the inclination of the first guide roller mechanism or the second guide roller mechanism is realized by shifting a position of a screw hole of the mounting member.
Drive saw wheel and driven saw wheel, motor for rotating the drive saw wheel, first saw wheel base for rotatably supporting the drive saw wheel, and second saw wheel for rotatably supporting the driven saw wheel A base saw, a band saw stretched between outer peripheries of the first saw wheel base and the second saw wheel base, the first saw wheel base and the second saw wheel base being spaced apart from each other, An opening for exposing a part, a first guide roller mechanism that is held by the first saw wheel base and guides the travel of the band saw, and is held by the second saw wheel base and guides the travel of the band saw A band saw having a second guide roller mechanism, wherein the band saw is provided with a guide member for guiding traveling in a direction crossing the traveling direction.
The band saw according to claim 7, wherein the guide member is the first guide roller mechanism and / or the second guide roller mechanism disposed obliquely toward a traveling direction of the band saw.
The band saw according to claim 7 or 8, wherein the guide member guides the band saw exposed in the opening.