WO2008035810A1

WO2008035810A1 - Miter saw having dust guide

Info

Publication number: WO2008035810A1
Application number: PCT/JP2007/068897
Authority: WO
Inventors: Tomomasa Nishikawa
Original assignee: Hitachi Koki Co., Ltd.
Priority date: 2006-09-20
Filing date: 2007-09-20
Publication date: 2008-03-27
Also published as: JP2008073920A; JP4780528B2

Abstract

A miter saw having a dust guide avoiding scatting of cutting chips and damage to the dust guide to provide a clean and safety working environment. The dust guide 60 ex-tends downward from a casing 51 of a cutting portion 50 for introducing the cutting chips toward a saw dust discharge section 56. An interlocking mechanism is provided for moving the dust guide 60 downward and upward with respect to the cutting portion 50 in response to the upward and downward pivot movement of the cutting portion 50, respectively.

Description

DESCRIPTION

MITER SAW HAVING DUST GUIDE

TECHNICAL FIELD

The present invention relates to a miter saw, and more particularly, to a miter saw having a dust guide.

BACKGROUND ART As shown in Fig. 8, a conventional miter saw 101 includes a base portion 110 and a cutting portion 150 pivo- tally movable toward and away from the base portion for cutting a workpiece mounted on the base portion. The base portion 110 includes a turntable 113 defining an upper surface IIOA on which a workpiece W such a wood block is mounted. ■The cutting portion 150 includes a motor 153 and a circular saw blade 154 rotationally driven by the motor 143. Upon rotation of the circular saw blade 154, the workpiece W can be cut . The cutting portion 150 also includes a saw cover 163 angularly movable about a rotation axis of the circular saw blade in synchronism with the pivotal movement of the cutting portion 150. Thus, the saw cover can prevent a user from accidentally touching the circular saw blade 154 during cutting operation.

Further, the cutting portion 150 has a dust bag or a dust case (not shown) those collecting cutting chips, and is formed with a discharge port 156A to which a hose of a dust collection device (not shown) is attachable. With this ar- rangement, scattering of the cutting chips around the miter saw during cutting operation can be prevented. A dust guide 160 made from a flexible material such as a rubber is at- tached to the cutting portion 150. The dust guide 160 can be deformed when the cutting portion is pivotally moved toward the base portion and the dust guide 160 is brought into abutment with the workpiece W. Japanese Patent Application Publication No. Hll-170214 discloses a miter saw provided with such deformable dust guide.

For cutting the workpiece W, the user is positioned in front of a handle 155 (rightward in Fig. 8) of the cutting portion 150 while gripping the handle 155, and pulls the handle 155 rightward so as to slidingly move the cutting portion 150 rightward. After the cutting portion 150 is moved to a position shown in Fig. 9, a switch 155A disposed at the handle 155 is pressed to energize the motor 153 to thus rotate the circular saw blade 154. Then, the handle 155 is moved downward in Fig. 9, so that the cutting portion 150 is pivotally moved downward about the rotation axis 132D in order to start cutting operation with respect to the workpiece W.

Next, in Fig. 10, after the cutting portion 150 has moved to its bottom dead center, the user pushes the handle 155 rearward, i.e., leftward in Fig. 10. As a result, cutting is continued while slidingly moving the cutting portion 150. In this case, cutting chips flow in a direction indicated by an arrow "a" in Fig. 13. The flow of the cutting chips is guided by the dust guide 160 and reaches a dust discharge port 156A. Cutting to the workpiece W is completed after the cutting portion 150 is pushed to the leftmost position as shown in Fig. 11, whereupon the user releases the switch 155A to stop rotation of the motor 153 so as to stop the operation of the circular saw blade 154.

However, in the conventional miter saw 101, the cutting chips may pass below the dust guide 160 as shown by an arrow "a" in Fig. 12 at an initial start up phase of the cutting operation. Accordingly, the cutting chips are scattered around the miter saw.

DISCLOSURE OF INVENTION

In order to avoid this problem, a dust guide 160 having a downwardly elongated shape is conceivable as shown in Fig. 14. However, such elongated dust guide 160 may be deformed and may be brought into contact with the circular saw blade 154 as shown in Fig. 15 during movement of the cutting portion 150 rearward after the cutting portion 150 is pivo- tally moved to its bottom dead center. Consequently, the dust guide 160 may be broken.

It is therefore, an object of the present invention to provide a miter saw capable of providing a clean and safety working environment by avoiding scattering of cutting chips and by avoiding contact of a dust guide with a circular saw blade thereby avoiding damage to the dust guide.

This and other objects of the present invention will be attained by providing a miter saw including a base portion, a cutting portion, a support portion, a discharge section, a dust guide, and an interlocking mechanism. A work- piece is to be mounted on the base portion. The cutting portion supports a circular saw blade and has a casing for partly covering the circular saw blade. The support portion supports the cutting section above the base portion and allows the cutting portion to be pivotally movable downward and upward relative to the base portion. The discharge section is provided at the cutting portion and is formed with an outlet port through which cutting chips generated from the workpiece pass toward outside of the cutting portion. The dust guide extends downward from the casing for intro- ducing the cutting chips toward the saw dust discharge section. The interlocking mechanism is configured to moves the dust guide downward and upward with respect to the cutting portion in response to the upward and downward pivot move- ment of the cutting portion, respectively.

Because of the interlocking mechanism, the dust guide will be moved upward when the cutting portion is moved downward for cutting. Therefore, accidental cutting to the dust guide by the circular saw blade due to deformation of the dust guide can be obviated. Further, since the dust guide will be moved downward when the circular saw blade is moved upward, scattering of cutting chips can be prevented because a positive cutting chip passage between the dust guide and the workpiece is not provided. Preferably, the casing includes a guide portion for guiding movement of the dust guide. The dust guide includes a guide section formed with a flexible material, and a base section that supports the guide section to the casing, the base section having an engaging portion engageable with the guide portion. Since the guide portion and the engaging portion are provided, a stabilized moving locus of the dust guide can be provided each time the dust guide is moved. Further, since the guide section is formed with a flexible material, any damage to the workpiece can be avoided when the guide section is brought into abutment with the workpiece .

Preferably, the interlocking mechanism includes a link mechanism, and the cutting portion further includes a safety cover pivotally movably supported to the casing and linked to the link mechanism. The link mechanism is configured to pivotally move the safety cover in response to the pivotal movement of the cutting portion. The dust guide is supported by the link mechanism. Since the link mechanism moves the safety cover in response to the pivotal movement of the cutting portion, a cutting operation can be performed without interference of the safety cover against the work- piece. Further, the link mechanism also serves as a component of the interlocking mechanism, a simple structure can result .

Preferably, the support portion includes a pivot support portion that pivotally movably supports the cutting portion, and the interlocking mechanism includes a link mechanism having one end pivotally connected to the pivot support portion.

Preferably, the support portion includes a pivot support portion to which the cutting portion is pivotally mova- bly supported, and the interlocking mechanism is configured to move the dust guide in interlocking relation to the pivotal movement of the cutting portion.

Preferably, the base portion has an upper surface and, the circular saw blade and the upper surface define an in- tersection line therebetween, and the support portion includes a pivot support portion and a slide support portion. The pivot support portion pivotally movably supports the cutting portion, and the slide support portion supports the pivot support portion and allows the pivot support portion to move in a direction parallel to the intersection line. With this arrangement, the cutting portion can be moved in the direction parallel to the intersection line during cutting operation. Thus, an elongated cutting is achievable.

BRIEF DESCRIPTION OF DRAWINGS

In the drawings: Fig. 1 is a left side view of a miter saw according to an embodiment of the present invention and showing an initial state immediately before the cutting operation;

Fig. 2 is a left side view of the miter saw according to the embodiment and showing a state where a cutting portion is pivotally moved toward a workpiece;

Fig. 3 is a left side view of the miter saw according to the embodiment and showing a state where the cutting portion is pivotally moved further downward to cut the workpiece; Fig. 4 is a perspective view of a dust guide provided in the miter saw according to the embodiment;

Fig. 5 is a right side view particularly showing the cutting portion and a link mechanism in the miter saw according to the embodiment and showing a state where the front region of the circular saw blade is largely covered with a safety cover;

Fig. 6 is a right side view particularly showing the cutting portion and the link mechanism in the miter saw according to the embodiment and showing a state where the saftey cover is partly retracted into a cover as a result of downward pivot movement of the cutting portion;

Fig. 7 is a cross-sectional view showing the relationship between the link mechanism and the dust guide in the miter saw according to the embodiment; Fig. 8 is a left side view of a conevntional miter saw and showing a state prior to cutting;

Fig. 9 is a left side view of the conventional miter saw and showing a frontmost position of a cutting portion;

Fig. 10 is a left side view of the conventional miter saw and showing a downward position of the cutting portion;

Fig. 11 is a left side view of the conventional miter saw and showing a rearward moving phase of the cutting portion;

Fig. 12 shows a flow of cutting chips during cutting operation in the conventional miter saw;

Fig. 13 is a left side view of the conventional miter saw and showing an initial cutting operation

Fig. 14 is a left side view of a conceivable arrangement of a dust guide; and

Fig. 15 is a left side view of the conceivable arrangement of the dust guide and shwoing a state where the dust guide is brought into contact with a circular saw blade .

DESCRIPTION OF REFERENCE NUMERALS 1 miter saw 10 base portion

1OA upper surface

30 support portion

31 slide support portion 31A holding portion 32 pivot support portion 32A holder 32B slide bar

50 cutting portion

51 frame (casing) 52 cover

52A guide portion 54 circular saw blade 56 discharge section 60 dust guide 61 guide portion (guide section)

62 base portion (base section)

63 safety cover 64 protrusion (engaging portion) 70 link mechanism

BEST MODE FOR CARRYING OUT THE INVENTION A miter saw according to one embodiment of the present invention will be described with reference to Figs. 1 through 7. The expressions "front", "rear", "above" and "below" are used throughout the description to define the various parts when the miter saw is disposed in an orientation in which it is intended to be used.

The miter saw 1 is provided with a slide mechanism and includes a base portion 10, a support portion 30 and a cutting portion 50. The base portion 10 has an upper surface 1OA on which a workpiece W is to be mounted, and has a pin 11 serving as a connecting part between the base portion 10 and the support portion 30. The pin 11 is located at a rear side of the base portion 10 and has an axis extending in parallel to the upper surface 1OA.

The base portion 10 includes a base 12 and a turnta- ble 13 supported within and at a center of the base 12. The turntable 13 is rotatable in a horizontal plane about a vertical axis. The turntable 13 has an upper surface in flush with an upper surface of the base 12. These upper surfaces define the upper surface 1OA of the base portion 10. A pair of fences 14, 14 are provided to the base 12 and are arrayed in line with each other and spaced away from each other. These fences 14 extend in a direction perpendicular to the pin 11 for supporting one side face of the workpiece W. Incidentally, in Figs. 1 through 3, only one of the fences 14 is shown. A linear groove (not shown) is formed in the upper surface of the turntable 13. The linear groove extends in a direction perpendicular to the fences 14, 14 and at a space between the neighboring fences 14 and 14. The groove allows a part of a circular saw blade 54 (described later) to be entered thereinto when the cutting portion 50 is pivotally moved downward. The support portion 30 includes a slide support portion 31 and a pivot support portion 32. The slide support portion 31 extends upward from the upper surface 1OA. The slide support portion 31 has one end connected to the base 10 through the pin 11 so that the support portion 30 can be laterally tiltable about' the pin 11 relative to the upper surface 1OA of the base portion 10. The slide support portion 31 has another end provided with a holding portion 31A that holds a slide bar 32B (described later) . The pivot support portion 32 is supported on the slide bar 32B, so that the pivot support portion 32 is movable in a direction substantially parallel to an intersection line defined between the upper surface 1OA of the base portion 10 and the circular saw blade moved downward.

The pivot support portion 32 includes a holder 32A and the slide bar 32B. The holder 32A has a base end attached to the slide bar 32B for pivotally movably holding the cutting portion 50. The slide bar 32B is slidably movably supported by the holding portion 31A. Thus, the pivot support portion 32 is movable frontward/rearward while being supported by the holding portion 31A. The holder 32A has an upper portion provided with an arm 32C to which a pivot pin 32D is supported for pivotally movably supporting the cutting portion 50 about the pivot pin 32D. A spring 32E is interposed between the arm 32C and the cutting portion 50 for normally urging the cutting portion 50 upward with respect to the arm 32C. The holder 32A, the arm 32C, the pivot pin 32D and a rearmost end portion of a frame 51 (described later) constitute a hinge portion.

The cutting portion 50 mainly includes the frame 51, a cover 52, a motor 53 and the circular saw blade 54. The frame 51 has a rear portion pivotally movably supported to the holder 32A through the pivot pin 32D. The circular saw blade 54 has a rotation axis supported to the frame 51 and extending perpendicular to the frontward/rearward direction in a state shown in Fig. 1. The cover 52 is provided to the frame 51 so as to cover a generally upper portion of the circular saw blade 54. The frame 51 and the cover 52 define a casing of the cutting portion 50.

As shown in Fig. 3, in a state where the cutting portion 50 is pivotally moved toward the upper surface 1OA, a handle 55 is provided at a front side of the cover 52. The handle 55 is provided with a switch 55A for controlling rotation of the motor 53. The cover 52 has a rear side provided with a cutting chip flowing portion 56 including an inlet (not shown) and an outlet 56A. Therefore, cutting chips generated at the intersection between the circular saw blade 54 and the workpiece W can be introduced into the flowing portion 56 through the inlet, and can be discharged through the outlet 56A. A dust collection unit such as a dust bag (not shown) is attachable to the outlet for accumulating cutting chips thereinto through the cutting chip flowing portion 56.

The motor 53 is disposed at the upper portion of the frame 51 for rotationally driving the circular saw blade 54. A dust guide 60 is attached to the lower rear portion of the cover 52 at a position in confrontation with a rear lower portion of the circular saw blade 54. The dust guide 60 is adapted for introducing cutting chips generated at the intersection between the circular saw blade 54 and the work- piece W into the cover 52.

As shown in Fig. 7, the cover 52 has opposing walls. A part of an inner surface of one of the opposing walls serves as a guide surface 52A for attachment of the dust guide 60 to the cover 52. The guide surface 52A is formed with a guide groove 52a extending in a generally circumferential direction of the circular saw blade 54. An opposite wall of the cover 52 is formed with a through-hole 52b penetrating through a thickness of the wall. As shown in Fig. 4, the dust guide 60 includes a guide portion 61 and a base portion 62. The guide portion 61 is made from a deformable or flexible material such as a rubber. Therefore, any injury to the workpiece can be avoided even when the guide portion 61 is brought into abut- ment with the workpiece W. The guide portion 61 has a U- shape cross-section and includes a pair of trapezoidal side wall portions 61A, 61B and a rectangular bottom wall portion 61C from which each side wall portion extends. The guide portion 61 has an inner surface along which cutting chips flow upward in Fig. 4 toward the cutting chip flowing portion 56. Each side wall portions 61A, 61B is formed with an elongated through-hole (not shown) at a longitudinally one end portion thereof (upper portion in Fig. 4) . Each elongated through-hole extends in a circumferential direction of the circular saw blade 54. Positions of the guide groove 52a and the through-hole 52b correspond to the pair of side walls 61A, 61B of the dust guide 60.

The base portion 62 is provided at the upper end portion of the guide portion 61, and is made from non- deformable rigid material. The base portion 62 has a U-shape cross-section and includes a pair of trapezoidal side wall sections 62A, 62B and a rectangular bottom wall section 62C from which each side wall portion extends. Each outer surface of each side wall section is in surface contact with each inner surface of each side wall portion of the guide portion 61, and an outer surface of the bottom wall section 62C is in surface contact with the inner surface of the bottom wall portion 61C. Thus, the base portion 62 and the guide portion 61 are fixed together.

The side wall section 62A has a protrusion 64 projecting from its outer surface and extending through the elongated through-hole of the side wall portion 61A. The other side wall section 62B is formed with a female thread 62b in alignment with the elongated through-hole formed in the side wall portion 61B of the guide portion 61. A threaded bolt 65 extends through the through-hole 52b of the cover 52 and elongated through-hole of the side wall portion 61B, and is threadingly engaged with the female thread 62b of the side wall section 62B.

The protrusion 64 is continuously engaged with the guide groove 52a of the guide portion 52 of the frame 51. The threaded bolt 65 is movable within the length of the elongated through-hole. Further, the protrusion 64 is also slidingly movable relative to the guide groove 52a. Accordingly, the dust guide 60 is movable with respect to the cover 52 along the guide groove 52 in the circumferential direction of the circular saw blade 54.

The cutting portion 50 also includes a safety cover 63 for covering a front lower portion of the circular saw blade 54. As shown in Fig. 5, the safety cover 63 has a generally sector shape and is partly retractable into the cover 52. The safety cover 63 is pivotally movable about the rotation axis of the circular saw blade 54 with respect to the frame 51 and the cover 52. The safety cover 63 is linked to a link mechanism 70 (described later) in order to change covering area of the safety cover 63 over the circular saw blade 54 depending on the pivot posture of the cutting portion 50. The safety cover 63 is formed with an elongated slot 63a generally extending in a radial direction of the circular saw blade 54.

The link mechanism 70 is provided at the cutting portion 50. As shown in Fig. 5, the link mechanism 70 includes a generally inverted S-shaped link member having one end pivotally movably connected to the holder 32 and has another end slidably movable with respect to the elongated slot 63a of the safety cover 63. The link member includes a linear portion extending between the holder 32 and a portion adjacent to the rotation axis of the circular saw blade 54, and a roundabout portion between the linear portion and the elongated slot 63a. The roundabout portion is detoured upward with respect to the rotation axis of the circular saw blade 54.

As shown in Fig. 7, a shaft portion of the bolt 65 is in seated on the linear portion of the link member 70. The shaft portion is slidable relative to the linear portion in the longitudinal direction thereof in accordance with the change in orientation of the linear portion depending on the pivot posture of the cutting portion 50. In a state shown in Fig. 1, the cutting portion 50 is at its uppermost and frontmost position, and the workpiece W is mounted on the turntable 13. In this state, the dust guide 60 protrudes downward toward the workpiece W because of the position and orientation of the link mechanism 70. Further, the safety cover 63 protrudes from the cover 52 in the clockwise direction in Fig. 1 because of the link mechanism 70 so that the safety cover 63 covers the circular saw blade 54 with the largest covering area.

Next, for starting cutting, the user grips the handle 55 to depress the switch 55A. Thus, the motor 53 is energized to start rotation of the circular saw blade 54. Then, the handle 55 is shifted downward as shown in Fig. 2, so that the link mechanism 70 pushes the shaft of the threaded bolt 65 upward to move the dust guide 60 upward with respect to the cutting portion 50 in synchronism with pivotally downward movement of the cutting portion 50. At the same time, the safety cover 63 is pivotally moved in a counterclockwise direction in Fig. 1, so that the safety cover 63 is partly retracted into the cover 52.

During retracting motion of the dust guide 60 into the cutting portion 50, a flow of the cutting chips is guided by the dust guide 60 toward the cutting chip flowing portion 56, so that the cutting chips can be discharged out of the outlet 56A. During further movement of the cutting portion 50 toward its lowermost pivot position as shown in Fig. 3, the dust guide 60 is further retracted into the cut- ting portion 50. Accordingly, accidental contact of the dust guide with the circular saw blade 54 can be avoided to obviate any damage to the dust guide 60. In this case, the safety cover 63 is further pivotally moved in counterclockwise direction into the cover 52 to provide the most re- tracted position as shown in Fig. 3. When the cutting portion 50 is moved, upward, the dust guide 60 is moved downward. Therefore, the cutting chips can still be blocked by the dust guide 60 to avoid scattering of the cutting chips. Further, the link mechanism for pivotally moving the safety cover 63 can also perform as an interlocking mechanism for moving the dust guide 60 in interlocking relation to the pivotal motion of the cutting portion 50. Therefore, the numbers of mechanical parts can be reduced.

While the invention has been described in detail and with reference to the specific embodiment thereof, it would be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention. For example, in the depicted embodiment, the bolt 65 is positioned on the link mechanism 70 and the relatively slidable with respect to the link mechanism in the longitudinal direction thereof. However, the corresponding bolt can be pivotally movable with respect to the link mechanism.

Further, the dust guide 60 is movable upward and downward by the link mechanism 70 in the above-described embodiment. However, other arrangement is conceivable without relying on the link mechanism for moving the dust guard in synchronism with the pivotal movement of the cutting portion 50 toward and away from the base portion 10.

Furthermore, in the miter saw according to the embodiment, the cutting portion 50 is movable frontward/ rear- ward by means of the slide bar 32B. However, a miter saw in which the cutting portion is immovable in the frontward/ rearward direction is also available in the present invention. Moreover, a material of the guide portion 51 of the dust guide 60 other than a rubber is also available.

INDUSTRIAL APPLIACBILITY

The miter saw according to the present invention exhibits advantageous function when using in a narrow installation site.

Claims

1. A miter saw comprising: a base portion on which a workpiece is to be mounted; a cutting portion supporting a circular saw blade and having a casing for partly covering the circular saw blade; a support portion that supports the cutting section above the base portion and allows the cutting portion to be pivotally movable downward and upward relative to the base portion; a discharge section provided at the cutting portion and formed with an outlet port through which cutting chips generated from the workpiece pass toward outside of the cutting portion; a dust guide extending downward from the casing for introducing the cutting chips toward the saw dust discharge section; and an interlocking mechanism configured to move the dust guide downward and upward with respect to the cutting portion in response to the upward and downward pivot move- ment of the cutting portion, respectively.

2. The miter saw as claimed in claim 1, wherein the casing includes a guide portion for guiding movement of the dust guide; and wherein the dust guide comprises a guide section formed with a flexible material, and a base section that supports the guide section to the casing, the base section having an engaging portion engageable with the guide portion.

3. The miter saw as claimed in claim 1, wherein the interlocking mechanism comprises a link mechanism; and wherein the cutting portion further comprises a safety cover pivotally movably supported to the casing and linked to the link mechanism, the link mechanism being con- figured to pivotally move the safety cover in response to the pivotal movement of the cutting portion, the dust guide being supported by the link mechanism.

4. The miter saw as claimed in claim 1, wherein the support portion comprises a pivot support portion that pivotally movably supports the cutting portion; and wherein the interlocking mechanism comprises a link mechanism having one end pivotally connected to the pivot support portion.

5. The miter saw as claimed in claim 1, wherein the support portion comprises a pivot support portion to which the cutting portion is pivotally movably supported; and wherein the interlocking mechanism is configured to move the dust guide in interlocking relation to the pivotal movement of the cutting portion.

6. The miter saw as claimed in claim 1, wherein the base portion has an upper surface and, the circular saw blade and the upper surface define an intersection line therebetween; and wherein the support portion comprises: a pivot support portion that pivotally movably supports the cutting portion; a slide support portion supporting the pivot support portion and allows the pivot support portion to move in a direction parallel to the intersection line.

7. The miter saw as claimed in claim 6, wherein the casing includes a guide portion for guiding movement of the dust guide; and wherein the dust guide comprises a guide section formed with a flexible material, and a base section that supports the guide section to the casing, the base section having an engaging portion engageable with the guide portion.

8. The miter saw as claimed in claim 6, wherein the interlocking mechanism comprises a link mechanism; and wherein the cutting portion further comprises a safety cover pivotally movably supported to the casing and linked to the link mechanism, the link mechanism being configured to pivotally move the safety cover in response to the pivotal movement of the cutting portion, the dust guide being supported by the link mechanism.

9. The miter saw as claimed in claim 8, wherein the link mechanism has one end pivotally connected to the pivot support portion.

10. The miter saw as claimed in claim 6, wherein the interlocking mechanism is configured to move the dust guide in interlocking relation to the pivotal movement of the cut- ting portion.