JP4531624B2 - Cover of cutting blade in cutting machine - Google Patents

Description

  The present invention relates to a cover that covers the cutting blade in a cutting machine having a rotating circular cutting blade.

In this type of cutting machine, a table-type circular saw is provided in which a cutting machine body provided with a rotating circular cutting blade is provided to be movable up and down with respect to a table for fixing a cutting material. In this tabletop circular saw machine, the upper half of the circular cutting blade is accommodated in the blade case, and the lower half of the circular cutting blade is closed by a safety cover that opens and closes in conjunction with the vertical movement of the cutting machine body. It is supposed to be covered.
This safety cover opens when the cutting machine main body is moved downward with respect to the cutting material fixed on the table so that the cutting blade is exposed and when the cutting machine main body is moved up, The cutting blade is closed to cover the lower half of the range. For this reason, when the cutting machine is not used, the entire cutting blade is covered with the blade case and the safety cover to prevent inadvertent contact with other parts.
No. 6-9765 Utility Model Registration No. 2604273

In recent years, cutting machines having a laser beam irradiation device have been provided for the purpose of increasing the cutting accuracy of the cutting machine. This laser beam irradiation apparatus may be attached to a blade case that can efficiently illuminate the cutting site. In this case, the width of the blade case may be larger than the conventional case. In general, when the width of the blade case is increased, the width of the safety cover supported so as to be openable and closable is also increased.
However, when the width of the conventional blade case and the safety cover is increased, there is a problem that unpleasant resonance noise is generated due to a delicate correlation between the rotational speed of the cutting blade and the distance from the cutting blade to the safety cover and the like. This occurs when sound waves generated by the high-speed air flow near the cutting blade are reflected on the safety cover and the generated sound waves further interfere with the reflected waves.
The present invention provides a cutting machine in which the generation of resonance noise due to rotation of the cutting blade is suppressed even when the width of the blade case and the safety cover is increased for the purpose of securing the arrangement space of the laser beam irradiation device or the like. For the purpose.

For this reason, this invention was set as the cutting machine of the structure described in each claim of a claim.
According to the cutting machine according to claim 1, the flow of air (for example, Karman vortex) generated by the rotation of the cutting blade is released to the outside of the cover through the ventilation hole, thereby suppressing the generation of resonance sound when the cutting blade rotates. can do.
The range in which the ventilation holes are provided, the size and the number of ventilation holes, and the like can be variously set according to various conditions such as the number of rotations of the cutting blade or the distance between the cutting blade and the side wall of the cover.
According to the cutting machine according to claim 1, the air flow generated by the rotation of the cutting blade in the blade case or the safety cover is released to the outside through the ventilation holes, so that the air flow is reduced to the side wall portion. It is possible to reduce the generation of resonance sound by suppressing reflection.
According to the cutting machine of claim 1 , when the cutting machine main body is moved upward to be positioned at the standby position, and when the safety cover is closed with respect to the blade case, the cutting blade has almost the entire circumference around the safety cover and the blade. Covered by a case. In this closed state, the outlet side end of the safety cover and the inlet side end of the blade case face each other.
In addition, when the safety cover is opened, the safety cover is set to be wider than the blade case when the safety cover is moved to a position that covers the outside of the blade case. For this reason, when the safety cover is closed as described above, in the state where the outlet side end portion and the inlet side end portion of the blade case face each other, the width suddenly reaches from the outlet side end portion to the inlet side end portion ( As a result, a portion where the flow width of the air flow is abruptly narrowed is generated.
In this case, the flow of air generated by the rotation of the cutting blade is hindered by the sudden narrowing of the flow path width generated when the safety cover is closed, and the inside of the vicinity of the end on the outlet side of the safety cover Karman vortices are likely to occur. According to the cutting machine of the first aspect, since the ventilation hole for escaping the air flow generated inside is formed in the side wall portion of the safety cover to the outside, the Karman vortex passes through the ventilation hole to the outside. Escaped. As a result, the generated Karman vortex is suppressed from being reflected on the side wall, thereby suppressing the generation of resonance.
According to the cutting machine according to claim 2 , since the fingertip cannot be passed through the ventilation hole, it is possible to prevent the user from inadvertently bringing the fingertip into contact with the cutting blade or the like. There is no loss of its original function.

Next, an embodiment of the present invention will be described with reference to FIGS. FIG.1 and FIG.2 has shown the whole cutting machine 1 (desk-type circular saw machine) provided with the safety cover 20 as an example of the cover described in the claim. The present embodiment is mainly characterized by the safety cover 20 described above, and the entire configuration of the other cutting machine 1 is the same as that of the prior art, and no particular change is required in the present embodiment, but will be briefly described below.
Reference numeral 3 in FIG. 1 is a table for fixing the cutting material S, and this is supported on the base 2 so as to be rotatable in the horizontal direction. A fence 4 for positioning the cutting material is attached to the upper surface of the table 3 with a slight gap. The rotation axis of the table 3 is set so as to be positioned on the material contact surface (front surface) 4 a of the fence 4.
A left / right tilt support portion 6 is supported on the rear portion (right end portion in FIG. 1) of the table 3 via slide bars 5 and 5. A support arm 7 is provided on the left and right tilt support portion 6 so as to extend upward and forward. A cutting machine main body 10 is supported at the tip of the support arm 7 via a support shaft 8 so as to be tiltable up and down.
The cutting machine body 10 includes a blade case 11 supported so as to be tiltable up and down with respect to the support arm 7. The blade case 11 covers a range of the upper half circumference of the circular cutting blade 13 (saw blade), and includes a side wall 11a covering the front side of the cutting blade 13 and a rear side (front side in FIGS. Side wall 11b covering the same). The cutting blade 13 is located between the side walls 11a and 11b. A drive motor 14 is attached to the side wall 11b on the back side. The cutting blade 13 is rotated at a high speed by the drive motor 14.
A laser beam irradiation device X is attached to the upper part of the blade case 11. A laser beam is irradiated from the laser beam irradiation apparatus X toward the cutting site, whereby a highly accurate cutting operation can be performed.

The safety cover 20 is provided so as to be openable and closable with respect to a range of the cutting blade 13 protruding from the blade case 11. FIG. 4 shows the safety cover 20 alone. 1, 2, and 4, the cutting blade 13 rotates in the direction indicated by the white arrow.
The safety cover 20 is manufactured by integral molding of a translucent synthetic resin, and has a U-shaped cross section having a front side wall portion 20a and a rear side wall portion 20b with respect to the cutting blade 13. A support edge 20c is integrally provided on the side wall 20a on the front side with respect to the cutting blade 13. The support edge portion 20c is supported substantially coaxially with the rotation axis J of the cutting blade 13 with respect to the side wall 11a on the front side of the blade case 11, so that the safety cover 20 can rotate with respect to the blade case 11. It is supported.
As shown in FIG. 3, the interval (width W20) between the side walls 20a and 20b of the safety cover 20 is set to be larger than the interval (width W11) between the side walls 11a and 11b of the blade case 11. Therefore, as shown in FIG. 2, when the safety cover 20 is opened, the safety cover 20 moves to an overlapping position along the outside of the blade case 11.
The end of the safety cover 20 corresponding to the outlet side in the rotational direction of the cutting blade 13 (the right end in FIG. 4, hereinafter referred to as the outlet side end 20e) is located on the cutting machine body 10 as shown in FIG. When moved and held at the standby position, the blade case 11 is almost abutted against the end of the blade case 11 (entrance side end 11c of the cutting blade 13), so that the entire cutting blade 13 is covered with almost no gap. It becomes. On the other hand, when the cutting machine body 10 is moved downward as shown in FIG. 2, the safety cover 20 is opened in the direction opposite to the rotation direction of the cutting blade 13 in conjunction with this. When the safety cover 20 is opened, the outlet side end portion 20e moves away from the inlet side end portion 11c of the blade case 11.

A plurality of ventilation holes 31 to 40 are formed in the side wall portion 20 b on the back side of the safety cover 20. In the case of the present embodiment, a total of ten vent holes 31 to 40 are arranged from the outlet side end portion 20e of the side wall portion 20b on the back side of the safety cover 20 to the middle in the circumferential direction. The ten ventilation holes 31 to 40 are arranged in four rows in the circumferential direction and the radial direction of the cutting blade 13, respectively.
Four vent holes 31 to 34 are arranged in parallel in the radial direction in the first circumferential row closest to the outlet side end 20e of the safety cover 20, and three vent holes 35 in the radial direction are arranged in the second circumferential row. 37 are arranged, two ventilation holes 38, 39 are arranged in the radial direction in the third row in the circumferential direction, and one ventilation hole is arranged in the fourth row in the circumferential direction farthest in the circumferential direction from the outlet side end portion 20e. 40 is formed.
The radially outermost ventilation holes 34, 37, 39, 40 in each row are arranged along the same circumference with respect to the rotation center of the cutting blade 13. Ventilation holes 33, 36, and 38 are arranged along the same circumference on the inner side, and ventilation holes 32 and 35 are arranged along the same circumference on the inner side.
The four ventilation holes 31 to 34 in the first row in the circumferential direction are formed in a generally triangular shape that is long in the circumferential direction. The ventilation holes 35 to 40 in the second, third, and fourth rows in the circumferential direction are each formed in a generally rhombus shape that is long in the circumferential direction. Thus, the vent holes 31 to 40 are arranged in an orderly manner without impairing the product design of the cutting machine 1.
All of the ventilation holes 31 to 40 are formed with a width dimension (opening width) in which a user's fingertip cannot enter.

As shown in FIG. 5, a large number of chips 13 b to 13 b are mounted at equal intervals on the peripheral edge of the circular main body disk 13 a of the cutting blade 13. As shown in the drawing, each chip 13b has a width dimension larger than the thickness of the main body disk 13a of the cutting blade 13. For this reason, each chip 13b is mounted in a state in which both end portions thereof protrude in the thickness direction of the main body disk 13a. When the cutting blade 13 provided with such a large number of chips 13b to 13b rotates at a high speed, the surrounding air is mainly involved in the movement of the chips 13b to 13b. An air flow F (wind) swirling in the same direction is generated.
The flow F of air generated by the rotation of the cutting blade 13 is discontinuously narrowed between the closed safety cover 20 and the blade case 11 as shown in FIG. 5 (W20>). W11), and as a result, Karman vortices KK are generated in the vicinity of the outlet side end portion 20e of the safety cover 20. The side wall portions 20a and 20b of the safety cover 20 resonate due to air vibration (turbulent flow) of a specific frequency accompanying the generation of the Karman vortices K to K, or the Karman vortices K to K are reflected to the side wall portions 20a and 20b. For this reason, it is considered that a large resonance sound is generated.
In this respect, according to the safety cover 20 according to the present embodiment described above, a large number of ventilation holes 31 to 40 are provided in the vicinity of the outlet side end portion 20e of the one side wall portion 20b. ~ K is escaped to the outside of the safety cover 20 through these ventilation holes 31 to 40, resonance of the side wall part 20b is suppressed, and reflection of the Karman vortices K ~ K is suppressed. The generation of resonance noise due to the discontinuous narrowing of the flow path width between the outlet side end 20e of the safety cover 20 and the inlet side end 11c of the blade case 11 is suppressed.

Various modifications can be made to the embodiment described above. For example, the size and shape of the ventilation holes, the number of ventilation holes, the range in which the ventilation holes are arranged, etc., match the wind noise that is expected to be generated depending on conditions such as the width of the safety cover and the rotational speed of the cutting blade. Various forms can be set. That is, depending on the wind noise that is expected to occur, there may be one ventilation hole.
Further, the shape of the ventilation holes is not limited to the triangular shape and the rhombus shape, and circular ventilation holes 50 to 50 may be provided in the vicinity of the outlet side end portion 20e as shown in FIG. 6, and as shown in FIG. The slit-shaped (groove-shaped) ventilation holes 51 to 51 may be provided, and as shown in FIG. 8, a mesh-like ventilation hole 52 may be provided in a certain range near the outlet side end portion 20e.
Moreover, although the structure which provides the ventilation holes 31-40 only in the side wall part 20b of the back side among the both-side wall parts 20a and 20b of the safety cover 20 was illustrated, the structure which provides a ventilation hole in the side wall part 20a of the front side or both of them It is good.
Furthermore, although the structure which provided the ventilation holes 31-40 in the safety cover 20 opened and closed in conjunction with the up-and-down movement of the cutting machine main body 10 was illustrated, as a structure which provides the same ventilation hole in the side walls 11a and 11b of the blade case 11 In addition, the same effect (wind noise reduction effect) as described above can be obtained. That is, in the embodiment illustrated above, when the safety cover 20 is opened, the safety cover 20 moves to the outer peripheral side of the blade case 11, and as a result, the width W20 of the safety cover 20 is set larger than the width W11 of the blade case 11. However, when the safety cover is set to be smaller than the width of the blade case and moves to the inside of the blade case when the safety cover is opened, the rotation direction of the cutting blade The exit end of the blade case (the end opposite to the entrance end 11c) is wider than the entrance end (the end opposite to the exit 20e) of the safety cover. Therefore, it is considered that Karman vortices K to K are generated in the vicinity of the outlet side end portion of the blade case. In this case, the same effect can be obtained by providing a ventilation hole in the side wall 11a (or 11b) near the outlet side end of the blade case.
Moreover, although the type of the cutting blade 13 provided with the chips 13b to 13b has been illustrated, the present invention is not limited to this type of saw blade, and for example, covers the periphery of the cutter in a cutting machine in which a food cutting cutter is mounted as a cutting blade. By providing ventilation holes in the cover, wind noise can be reduced.

1 is an overall side view of a desktop circular saw machine provided with a safety cover according to an embodiment of the present invention. This figure shows a state in which the main body of the cutting machine moves upward and is held at the standby position, and thus the safety cover 20 is closed. The white arrow in the figure indicates the direction of rotation of the cutting blade. 1 is an overall side view of a desktop circular saw machine provided with a safety cover according to an embodiment of the present invention. This figure shows a state in which the main body of the cutting machine is moved downward and held at the cutting position, and thus the safety cover 20 is opened. The white arrow in the figure indicates the direction of rotation of the cutting blade. It is a (3)-(3) arrow directional view of FIG. 1, Comprising: It is a cross-sectional view of a blade case and a safety cover. It is the side view which looked at the safety cover from the back side. The white arrow in the figure indicates the direction of rotation of the cutting blade. FIG. 5 is a cross-sectional view taken along line (5)-(5) in FIG. 4 and is a cross-sectional view of the safety cover. It is a side view of the safety cover provided with the vent hole of another form. It is a side view of the safety cover provided with the vent hole of another form. It is a side view of the safety cover provided with the vent hole of another form.

Explanation of symbols

1 ... Cutting machine (desktop circular saw)
DESCRIPTION OF SYMBOLS 2 ... Base 3 ... Table 4 ... Fence, 4a ... Material contact surface 5 ... Slide bar 6 ... Left-right tilting support part 7 ... Support arm 8 ... Spindle 10 ... Cutting machine main body 11 ... Blade case, 11a ... Side wall (front side) ), 11b ... side wall (back side)
13 ... Cutting blade, 13b ... Chip 14 ... Drive motor 20 ... Safety cover (cover)
20a ... Side wall (front side), 20b ... Side wall (back side), 20c ... Support edge 20e ... Outlet side end 31-40 ... Ventilation hole K ... Karman vortex F ... Air flow (wind)
W11 ... Flow path width at the inlet end of the blade case W20 ... Flow path width at the outlet end of the safety cover X ... Laser beam irradiation device

Claims (3)

A cutting machine main body having a rotating circular cutting blade is provided to be movable up and down with respect to the table on which the cutting material is placed, and the periphery of the cutting blade is covered with a blade case and a safety cover. The cover is opened and closed with respect to the blade case,
When the main body of the cutting machine moves upward and is held at the standby position, the safety cover is closed, the end of the safety cover on the outlet side in the rotational direction of the cutting blade, and the cutting blade of the blade case A cutting machine in which the end on the entrance side is opposed to the rotation direction, and the flow width of the air flow is narrowed from the exit end to the entrance end ,
The side wall portion of the safety cover, the flow of air generated by the rotation of the cutting blade provided ventilation holes for releasing to the outside of the safety cover, the outlet side end portion of the safety cover by narrowing of the channel width A cutting machine configured to release the turbulent flow generated by the air to the outside of the safety cover through the ventilation holes . The cutting machine according to claim 1 , wherein the ventilation hole is set to a size that does not allow a fingertip to pass therethrough. The cutting machine according to claim 1 or 2, wherein the ventilation holes are arranged in four rows in the circumferential direction of the cutting blade.

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