JP5252375B2 - Portable cutting machine - Google Patents

Description

  The present invention relates to a portable cutting machine, and more particularly to a portable cutting machine provided with a split blade.

In the portable cutting machine, when the cutting blade is clamped by the wood cut by the cutting blade, there is a possibility that a so-called kickback occurs in which the portable cutting machine is suddenly pushed back to the side opposite to the cutting direction. . In order to prevent this, as shown in Patent Document 1 and Patent Document 2, a split blade is provided behind the cutting blade. By providing the cutting blade, when the operator cuts the wood, the cutting blade enters the gap in the cut part of the wood, and the cutting resistance of the cutting blade is reduced by properly maintaining the gap. It is reduced. Further, since the weight of the portable cutting machine is increased by providing the split blade, it is required to reduce the size of the portable cutting machine in order to reduce the weight.
JP-A-8-336804 JP 57-156204 A

  By reducing the size of the portable cutting machine, the diameter of the cutting blade is also reduced. However, when the cutting blade is reduced in diameter, the cutting ability such as the cutting depth may be reduced.

  As is well known, portable circular saws are made by cutting a workpiece such as wood by an operator pushing the portable circular saw in the cutting direction and applying a propulsive force. However, if cutting powder adheres to the cutting blade, the cutting powder enters the gap between the cutting blade and the cut one side of the wood during the cutting operation, and the friction between the cutting blade and the workpiece increases, resulting in cutting. There was a problem that the propulsive force of the portable circular saw at the time of work decreased, resulting in a decrease in operability and cutting ability. Therefore, an object of the present invention is to provide a portable cutting machine provided with a cutting blade and having a cutting ability secured even if the blade is downsized.

In order to solve the above problems, the present invention includes a motor having an output shaft portion, a spindle connected to the output shaft portion and having a cutting blade for cutting a processing member fixed to be coaxially rotatable, and the cutting A housing having a saw cover that holds the blade and covers substantially half of the outer periphery of the cutting blade, and an opening that is connected to the housing and protrudes from the contact surface that contacts the processing member are formed. A base, a protrusion amount changing mechanism capable of changing a protrusion amount of the cutting blade from the opening, a supported portion provided on the housing and supported around the spindle, and a cutting direction of the cutting blade in the cutting direction of the cutting blade; A split blade mechanism having a split blade located on the rear side of the cutting blade and protruding from the corresponding contact surface, and the output shaft portion is arranged such that the axis of the output shaft portion is parallel to the axis of the cutting blade And a pinion gear at the tip The spindle is provided with a final gear that rotates coaxially and integrally, and between the final gear and the pinion gear, the final gear and the pinion gear mesh with each other and an axis parallel to the axis of the output shaft portion. A rotating intermediate gear is provided, and the housing includes a rotation support portion having a circumferential surface that rotatably supports the split blade mechanism around the spindle, and a protrusion amount from the opening portion of the cutting blade. When set to the maximum, the supported portion is supported by the rotation support portion other than the peripheral portion on the most base side of the rotation support portion, and the protrusion amount conversion mechanism A rocking support portion including a rocking shaft portion provided in front and parallel to the spindle; and a link portion provided on the rear side of the cutting blade with respect to the spindle, the split blade mechanism including the link A connection part connected to the link part, the connection part being connected to the link part And when the housing is swung relative to the base, the split blade mechanism is rotated around the rotation support portion in a direction opposite to the swinging direction of the housing. In a state where the housing is closest to the base, the contact surface passes through a point where an imaginary axis hanging from the contact surface to the central axis of the rotation support portion intersects the circumferential surface of the rotation support portion. The rim closest to the base of the supported part with respect to the imaginary line parallel to the imaginary line is substantially coincident with the imaginary line or located on the opposite side of the base, and the supported part Provided is a portable cutting machine having an abutting portion that abuts on the circumferential surface within a range of 180 ° or less around a central axis of a rotation support portion .

  According to such a structure, the gear diameter of the last gear arrange | positioned coaxially with a spindle can be made small. Therefore, the housing around the spindle can be made small, and when the housing is brought close to the base, the distance from the spindle to the base can be reduced, and the protruding amount of the cutting blade protruding from the base can be increased. In addition, it is possible to prevent the member constituting the portable circular saw from being disposed at a position close to the base around the rotation support portion in a state where the housing is closest to the base. That is, since there is no supported portion of the split blade mechanism around the rotation support portion at a position close to the base, the housing can be brought close to the base, and the amount of protrusion of the cutting blade from the base can be reduced while providing the split blade mechanism. Can be increased.

  According to such a configuration, since the peripheral edge closest to the base of the supported part is coincident with the imaginary line that is the base side end of the rotation support part or located on the side opposite to the base, There is no supported part at a position close to the base. Therefore, the housing can be further brought closer to the base, and the amount of protrusion of the cutting blade from the base can be increased.

  According to such a configuration, even when the cutting depth is changed, the distance between the cutting blade and the cutting blade can be kept at an appropriate value according to the cutting depth.

  According to such a configuration, the supported portion includes the abutting portion that abuts the circumferential surface within a range of 180 ° or less around the central axis of the supported rotation supporting portion. Even when the blade mechanism is rotated, the supported portion can be prevented from being located at a position close to the base.

  Further, either one of the housing and the split blade mechanism is provided with an arc-shaped portion having an arc shape centering on the central axis of the rotation support portion, and either the housing or the split blade mechanism is provided. On the other hand, it is preferable that an engagement portion that engages with the arc-shaped portion and restricts movement of the split blade mechanism other than the movement along the arc-shaped portion with respect to the housing is provided.

  According to such a configuration, the split blade mechanism can be held in the housing by the engagement between the engagement portion and the arc-shaped portion in addition to the contact between the supported portion and the rotation support portion. Further, since the movement of the cutting blade mechanism can be restricted by the engagement between the arcuate portion and the engaging portion, the cutting blade mechanism can be stably held so as to be rotatable around the rotation support portion.

  Further, the corresponding contact portion includes at least a front end side contact portion positioned on the rotation direction side with respect to the rotation support portion and a rear side contact portion positioned on the counter rotation direction side. It is preferable that an imaginary straight line connecting the engagement portion from the central axis of the rotation support portion is located between the rear contact portion and the rear contact portion.

  Further, it is preferable that the supported portion is supported on the rotation support portion by at least the tip side contact portion, the rear side contact portion, and the engagement portion.

  According to such a structure, the structure around the rotation support part of the split blade mechanism can be simplified, and can be stably and rotatably held by the supported part and the engagement part.

  Moreover, it is preferable that this engaging part is comprised from the pin engageable with this circular arc shape part.

  According to such a configuration, the movement of the split blade mechanism can be guided with a simple configuration.

  The engaging portion preferably has a shaft portion inserted into the arc-shaped portion and a head portion having a larger diameter than the shaft portion, and the head portion is preferably larger than the diameter of the arc-shaped portion.

  According to such a configuration, disengagement between the engagement portion and the connection portion is suppressed, and the movement of the split blade mechanism can be guided stably and reliably.

  A protective cover that covers a portion of the cutting blade that protrudes from the corresponding contact surface of the base and is rotatably supported by the rotational support portion; and an elastic body that maintains the protective cover in a predetermined position. The elastic body is provided at one end side in the vicinity of the rotation support portion of the protective cover, and the other end side is located on the counter-rotation support portion side of the split blade mechanism and in the vicinity of the mounting position of the split blade. Is preferably provided.

  According to such a configuration, the cutting blade can be covered with the protective cover, and the protective cover can be rotated according to the rotation of the split blade mechanism when the cutting depth is adjusted. Therefore, the cutting blade can be protected with the protective cover stably even when the cutting depth is changed.

  Further, it is preferable that the one end side of the elastic body substantially coincides with the imaginary line or is located on the side opposite to the base when the protective cover rotates most about the rotation support portion.

  According to such a configuration, when the protective cover is rotated in a state where the cutting depth is maximum, the portion of the protective cover where the one end side of the elastic body is attached is opposite to the base portion side peripheral portion of the rotational support portion. Since it is located on the part side, the cutting depth can be maintained.

Also, provided on the output shaft portion output shaft portion coaxially and integrally rotated, e Bei a fan for generating a fan-like, and the cutting blade is coaxially integrally rotatably fixed to the spindle, the The fan air is preferably discharged toward the split blade.

Or the direction of rotation of the fan was, it is possible to match the direction of rotation of the cutting blade, the orientation of the fan air vortex coincides with the direction of the flow of air caused by the rotation of the cutting blade. Thereby, the fan wind discharged to the vicinity of the cutting blade is not disturbed, the fan wind can be suitably exhausted around the cutting blade, and the chips of the cutting blade can be suitably discharged. Therefore, it becomes difficult for chips to enter between the cutting blade and the processing member, and an increase in friction between the cutting blade and the processing member can be suppressed. Further, the cutting blade is rotated so that the outer peripheral portion moves upward (in the direction close to the contact surface) in front of the cutting blade and the outer peripheral portion moves downward (in the direction away from the contact surface) behind the cutting blade. In this case, the fan wind blows from the upper side to the lower side behind the cutting blade. Since the split blade is positioned below the housing or the like in which the fan is held, the fan wind can be discharged toward the split blade more preferably by rotating in the rotation direction.

  The housing has a motor housing that holds the motor and incorporates the fan, and the split blade is provided through the opening, and the housing is provided near the opening and in the saw cover. It is preferable that an air supply passage opening in the vicinity of the split blade and opening in the motor housing is formed.

  According to such a configuration, the fan wind generated by the fan can be suitably exhausted around the split blade. Therefore, the chip removal performance around the split blade can be further improved.

  A protective cover that is rotatably supported by the rotating shaft of the cutting blade and covers a portion of the cutting blade that protrudes from the opening of the base; It is preferable that a guide hole for guiding wind to the split blade is formed.

  Further, it is preferable that at least a part of the guide hole is located between the air supply passage and the split blade when the protective cover is rotated in the saw cover around the rotation shaft.

  According to such a configuration, the fan wind is prevented from being blocked by the protective cover, and the fan wind can be more efficiently guided to the cutting blade.

  Moreover, it is preferable that a current plate that is inclined toward the split blade is provided in the air supply passage.

  According to such a configuration, the fan wind can be discharged to the periphery of the split blade more efficiently.

  According to the portable cutting machine of the present invention, it is possible to prevent the cutting ability from being lowered even if the cutting blade is provided and the size is reduced.

  A portable cutting machine according to an embodiment of the present invention will be described with reference to FIGS. A circular saw 1 which is a portable cutting machine shown in FIGS. 1 and 2 includes a housing 2, a circular saw blade 3 (FIG. 2), a gear mechanism 4 (FIG. 1), a protruding amount changing mechanism 5, Mainly composed of the base portion 6 and the split blade mechanism 7 (FIG. 2), the line of intersection defined by the cross saw blade 3 and a contact surface 61A (described later) of the base portion 6 is extended. One of the directions to be performed is defined as a front side in the cutting direction and a rear side in the opposite direction. Further, the direction from the circular saw blade 3 toward the motor 24 described later is defined as the left side, and the opposite is defined as the right side. The normal direction of the contact surface 61A described later and the direction from the housing 2 toward the base portion 6 is defined as the lower side. The opposite is defined as the upper side.

  As shown in FIG. 1, the housing 2 includes a motor accommodating portion 21 that accommodates a motor 24, a saw cover 22 that accommodates the circular saw blade 3, and a saw cover 22 that is integrally formed with the motor accommodating portion 21. It is mainly comprised from the gear accommodating part 23 by being united.

  The motor accommodating portion 21 is formed with an air inlet 21a that opens to the left side of the motor 24 in a state where the motor 24 is accommodated, and a handle 21A serving as a place to be gripped by an operator is provided on the outer peripheral portion. It has been. The handle 21A is provided with a switch (not shown) for controlling the driving of the motor 24. The motor 24 accommodated in the motor accommodating portion 21 has an output shaft portion 24A that protrudes from the right end portion and has the left-right direction as the rotation axis direction. A pinion gear 24B is provided at the tip of the output shaft portion 24A. A fan 25 is provided at the base end of the portion 24A. The fan 25 is configured to take in outside air from the air inlet 21a into the motor housing portion 21 when rotated counterclockwise when viewed from the right side.

  The saw cover 22 is disposed on the right side of the handle 21A. As shown in FIG. 2, the saw cover 22 is mainly composed of a saw cover main body 22A that is integral with the housing 2 and forms a part of the housing 2, and a safety cover 22B provided on the saw cover main body 22A. The blade part of the circular saw blade 3 is covered.

  The saw cover main body 22A is made of metal and covers substantially half of the circular saw blade 3 as shown in FIG. A connecting portion 22D connected to a swing support portion 51 described later is defined at the front end portion of the saw cover main body portion 22A.

  The safety cover 22B is positioned below the saw cover main body portion 22A, and the rotation support described later is rotatable about the rotation axis of the circular saw blade 3 along the outer edge of the saw cover main body portion 22A in the circumferential direction. It is provided in the part 23A. Further, in the safety cover 22B, a first spring mounting portion 22H to which one end of a spring 22E that is an elastic body is connected is provided at a position located above the rotation support portion 23A. The other end of the spring 22E is attached to a position behind the rotation support portion 23A of the split blade mechanism 7. According to such a configuration, the safety cover 22B is urged counterclockwise by the spring 22E when viewed from the right side with respect to the split blade mechanism 7 and the saw cover body 22A. Therefore, in a state where the cutting operation is not performed, the safety cover 22B covers the portion of the circular saw blade 3 below the saw cover main body portion 22A that cannot be covered by the saw cover main body portion 22A from the rear end side toward the front end side. Yes.

  Further, a portion where the circular saw blade 3 is exposed is formed between the front end side of the saw cover main body 22A and the front end side of the safety cover 22B, and this exposed portion cuts the wood which is a workpiece. Then, the circular saw 1 advances toward the front side. A support pin 22C that protrudes into the saw cover main body 22A is fixedly provided at a position that is an upper rear portion of a later-described rotation support 23A in the saw cover main body 22A. As shown in FIG. 5, the support pin 22C includes a head portion 22F and a shaft portion 22G. The head portion 22F is configured to have a larger diameter than the shaft portion 22G, and the width of a first long hole 71a described later. The shaft portion 22G is configured to have a larger diameter and can be inserted into a first long hole 71a described later.

  As shown in FIG. 1, the gear housing portion 23 is located between the saw cover 22 and the motor housing portion 21, and the gear mechanism 4 is built therein as shown in FIG. 6. As shown in FIG. 3, the gear housing portion 23 is provided with a rotation support portion 23 </ b> A that holds a spindle 43 described later and supports the split blade mechanism 7. As shown in FIG. 7, the rotation support portion 23 </ b> A has a circumferential surface 23 </ b> B formed on the outer peripheral portion, and the central surface of the circumferential surface 23 </ b> B is parallel to the axis of the output shaft portion 24 </ b> A (FIG. 1). It is comprised so that it may become.

  As shown in FIG. 6, the gear mechanism 4 mainly includes the pinion gear 24 </ b> B, the intermediate gear 41, the final gear 42, and the spindle 43. The intermediate gear 41 includes a first intermediate gear 41A and a second intermediate gear 41B that is smaller in diameter than the first intermediate gear 41A and rotates coaxially with the first intermediate gear 41A. The first intermediate gear 41A meshes with the pinion gear 24B. The second intermediate gear 41B meshes with the final gear 42 and is supported by the gear housing portion 23 via a bearing so as to be rotatable about an axis parallel to the output shaft portion 24A. The final gear 42 meshes with the second intermediate gear 41B, and is fixed to the spindle 43 so as to rotate coaxially so as to be rotatable about an axis parallel to the output shaft portion 24A. The spindle 43 is parallel to the output shaft portion 24A, is supported by being supported by a bearing in the rotation support portion 23A, the right end is located in the saw cover body portion 22A (FIG. 3), and the final gear 42 is coaxial with the left end. It is fixed so as to rotate integrally. Further, as shown in FIG. 3, a circular saw blade 3 is attached to the right end of the spindle 43 by a bolt 31, a flange 32, and the like so as to rotate coaxially with the spindle 43.

  By adopting such a configuration, the spindle 43 is driven by the output shaft portion 24A via the intermediate gear 41, so that the reduction ratio can be increased with the gear diameter of the final gear 42 being small. Therefore, the housing 2 around the spindle 43 can be reduced in size and compactly integrated. As shown in FIG. 2, the outer peripheral edge of the circular saw blade 3 attached to the spindle 43 from the outer periphery of the housing 2 around the spindle 43. The distance to can be taken large.

  As shown in FIG. 3, in the gear housing portion 23, an air supply passage 23 a that opens to a position near the fan 25 (FIG. 1) in the motor housing portion 21 and a position near a later-described split blade 72 of the saw cover 22. Is formed. As shown in FIG. 4, a rib 23 </ b> C that is a rectifying plate that rectifies toward the split blade 72 is provided inside the air supply passage 23 a. By adopting such a configuration, the fan wind generated by the fan 25 can be preferably guided to the vicinity of the split blade 72 in the saw cover 22.

  Further, since the intermediate gear 41 is interposed between the pinion gear 24B coaxial with the output shaft portion 24A and the final gear 42 coaxial with the spindle 43, the rotational direction of the circular saw blade 3 mounted on the spindle 43 depends on the output direction. The rotation direction of the fan 25 mounted on the shaft portion 24A is the same. The circular saw blade 3 rotates so that the outer peripheral portion moves upward at the front and the outer peripheral portion moves downward at the rear (rotates counterclockwise when the circular saw blade 3 is viewed from the right side). Behind the saw blade 3, the fan wind is blown from above to below. Since the later-described split blade 72 is positioned below the housing 2 on which the fan 25 is held, the fan wind is more appropriately divided by rotating the circular saw blade 3 and the fan 25 in the above-described rotation direction. It can be discharged toward the blade 72.

  As shown in FIG. 1, the base portion 6 is mainly composed of a base member 61, a first bevel plate 62, and a second bevel plate 63, and the base portion 6 is a housing through a protruding amount changing mechanism 5. 2 is tiltably supported. The base member 61 is a main constituent material of the base portion 6 and is made of a metal and is formed of a substantially rectangular plate material. The base member 61 is disposed such that the longitudinal direction thereof coincides with the front-rear direction, and a contact surface 61A is defined on the lower surface that contacts the processing member as shown in FIG. The contact surface 61A is formed with an elongated opening (not shown) extending in the longitudinal direction. The base member 61 is configured such that the circular saw blade 3 and the safety cover 22B enter the opening (not shown).

  As shown in FIGS. 1 and 2, the second bevel plate 63 is provided in the base member 61 at a front position of an opening (not shown). As shown in FIG. 2, the second bevel plate 63 is disposed upright on the base member 61, and includes a second tilting shaft portion 63 </ b> A extending in the cutting direction. A swing support portion 51 described later is pivotally supported by 63A so as to be tiltable. The second bevel plate 63 is formed with a second long hole (not shown) having an arc shape with the second tilting shaft portion 63A as the center.

  As shown in FIGS. 1 and 2, the first bevel plate 62 is erected from the rear position in the cutting direction of the opening (not shown) of the base member 61, and is on the axial extension line of the second tilting shaft portion 63A. A first tilting shaft portion 62A that pivotally supports a link portion 52, which will be described later, is provided, and an arc-shaped first long hole (not shown) centering on the first tilting shaft portion 62A is formed.

  As shown in FIG. 2, the protrusion amount changing mechanism 5 mainly includes a swing support portion 51, a link portion 52, and a screw portion 53. The swing support part 51 includes a base part 51A having a pair of arm parts, and a shaft part 51B disposed across the arm parts of the base part 51A. The base portion 51A is pivotally supported by the second tilting shaft portion 63A, can be tilted with respect to the base portion 6, is formed with a screw hole (not shown), and the second long hole (not shown) passes through the screw hole. A second knob 51C provided with a screw to be engaged is screwed. By tightening the second knob 51C, the tilt angle of the swinging support portion 51 with respect to the second bevel plate 63 can be fixed at a predetermined angle. The shaft portion 51B is disposed in a direction orthogonal to the front-rear direction and is disposed across the arm portion of the base portion 51A, and pivotally supports the coupling portion 22D of the saw cover main body portion 22A between the arm portions of the base portion 51A. Yes.

  The link part 52 is arrange | positioned in the saw cover 22, and is mainly comprised from 52 A of base parts, and the link 52B. The base portion 52A is pivotally supported by the first tilting shaft portion 62A, can be tilted with respect to the base portion 6, is formed with a screw hole (not shown), and a first elongated hole (not shown) is formed in the screw hole. A first knob 52C provided with a screw that passes therethrough is screwed. By tightening the first knob 52C, the tilt angle of the link portion 52 with respect to the first bevel plate 62 can be fixed at a predetermined angle.

  The link 52B is configured integrally with the base portion 52A and extends along the side surface of the circular saw blade 3 in the saw cover 22 and extends in an arc shape centering on the shaft portion 51B. Further, a long hole 52a is formed in the link 52B along the extending direction with the axial direction of the circular saw blade 3 as the penetrating direction. An engagement pin 52D that engages the split blade mechanism 7 is provided at the upper end portion of the link 52B.

  The screw portion 53 is disposed in the elongated hole 52 a, and a knob 53 </ b> A (FIG. 1) that rotates the screw portion 53 is disposed outside the saw cover 22 and is rotatably supported by the saw cover 22. By turning the knob 53A, the screw portion 53 and the link 52B are loosened, so that the screw portion 53 moves in the long hole 52a with respect to the link 52B. Since the screw part 53 can move with respect to the link 52B, the housing 2 to which the screw part 53 is connected can be moved with respect to the base part 6 to which the link 52B is connected. 2 is set to a predetermined swing angle, and the protruding amount of the circular saw blade 3 from the base portion 6 can be set to a desired value. After the protrusion amount of the circular saw blade 3 is set to a desired value, the protrusion amount of the circular saw blade 3 protruding from the base portion 6 is accurately defined by reversing the knob 53A and fastening the screw portion 53. be able to.

  The screw portion 53 is also inserted into a second long hole 71b described later, and fixes a supported portion 71 described later to the housing 2. Further, since the link portion 52 integrated with the housing 2 via the screw portion 53 is pivotally supported by the first tilting shaft portion 62A as described above, the housing 2 has the first tilting shaft portion 62A and the second tilting shaft portion. The structure supported by the shaft portion 63A is adopted, and the housing 2 and the circular saw blade 3 supported by the housing 2 can be tilted around the first tilting shaft portion 62A and the second tilting shaft portion 63A.

  As shown in FIG. 2, the split blade mechanism 7 is mainly composed of a supported portion 71, a split blade 72, and a connection portion 73. As shown in FIG. 7, the supported portion 71 includes a first contact portion 71A and a second contact portion 71B, and an arc-shaped first long hole 71a and a second long hole 71b (FIG. 2) are formed. Has been configured.

  The first contact portion 71A and the second contact portion 71B each have a contact surface along the circumferential surface 23B of the rotation support portion 23A, and the circumferential surface of the rotation support portion 23A is the contact surface. 23B. The positional relationship between the first contact portion 71A and the second contact portion 71B is configured to contact the circumferential surface 23B within a range of 180 ° or less around the center O of the rotation support portion 23A.

  The first elongated hole 71a is disposed in the vicinity of the first contact portion 71A and the second contact portion 71B, and the contact surface between the first contact portion 71A and the second contact portion 71B is the rotation support portion 23A. In the state where it is in contact with the rotation support portion 23 </ b> A, the rotation support portion 23 </ b> A is configured in an arc shape centered on the center O. The support pin 22C is inserted into the first long hole 71a. The first long hole 71a is formed so that the width thereof is smaller than the head 22F (FIG. 5) of the support pin 22C. Therefore, when the support pin 22C is inserted into the first long hole 71a and attached to the saw cover main body portion 22A, the split blade mechanism 7 including the supported portion 71 moves in the left-right direction with respect to the saw cover main body portion 22A. Is regulated.

  The first abutment portion 71A and the second abutment portion 71B with respect to the support pin 22C are portions of a timepiece that abut on the circumferential surface 23B of the first abutment portion 71A in the circumferential direction of the rotation support portion 23A. An imaginary straight line VL1 that connects the support pin 22C from the center O of the rotation support portion 23A is located between the rotation rear end side and the clockwise front end side of the portion that contacts the circumferential surface 23B of the second contact portion 71B. Are arranged as follows.

  The split blade mechanism 7 is supported by the first support part 71A and the second contact part 71B coming into contact with the rotation support part 23A, but the first contact part 71A and the second contact part 71B. Means that the first contact portion 71A and the second contact portion 71B are separated from the rotation support portion 23A. There is a fear. On the other hand, by inserting the support pin 22C into the first long hole 71a, the movement of the first support portion 71A and the second contact portion 71B in the diameter direction of the rotation support portion 23A can be restricted. it can.

  Further, since the first contact portion 71A and the second contact portion 71B are only in contact with the rotation support portion 23A, the supported portion 71 rotates around the support pin 22C around the support pin 22C. It is assumed that However, as described above, the positional relationship between the support pin 22C and the first contact portion 71A and the second contact portion 71B is such that the virtual straight line VL1 connecting the support pin 22C from the center O of the rotation support portion 23A is the first. Since it is configured to be positioned between the contact portion 71A and the second contact portion 71B, even if the supported portion 71 is rotated about the support pin 22C, the first contact portion 71A and Any one of the second contact portions 71B is in strong contact with the rotation support portion 23A and prevents the supported portion 71 from rotating. Accordingly, the supported portion 71 is allowed to move only in the circumferential direction on the circumferential surface with respect to the rotation support portion 23A, and is in a state of being rotatably held by the rotation support portion 23A.

  As described above, the supported portion 71 is held by the first abutting portion 71A and the second abutting portion 71B disposed around the center O in a range of 180 ° abutting on the rotation supporting portion 23A. Therefore, on the circumferential surface 23B around the rotation support portion 23A, the supported portion 71 and the circumference are outside the range where the first contact portion 71A and the second contact portion 71B are in contact with the circumferential surface 23B. There is no need to provide a structure in contact with the surface 23B. Therefore, it is possible to adopt a configuration in which the supported portion 71 is not positioned below the rotation support portion 23A in a state where the split blade mechanism 7 is disposed around the rotation support portion 23A.

  More specifically, as shown in FIGS. 2 and 7, an imaginary axis that hangs down from the contact surface 61 </ b> A to the central axis of the rotation support portion 23 </ b> A in a state where the housing 2 is closest to the base portion 6. For the virtual line VL2 that passes through the point P where AX intersects the circumferential surface 23B and is parallel to the contact surface 61A, the peripheral edge closest to the base portion 6 of the supported portion 71 substantially coincides with the virtual line VL2, or the virtual line VL2 It is comprised so that it may be located above.

  In such a configuration, since the supported portion 71 does not exist below the housing 2 (on the base portion 6 side) when the housing 2 is closest to the base portion 6, the housing 2 is brought close to the base portion 6 to the limit. be able to. Since the housing 2 is as close as possible to the base portion 6, the amount of protrusion of the circular saw blade 3 held by the housing 2 from the contact surface 61A can be increased. As described above, since the distance from the outer periphery of the housing 2 around the spindle 43 to the outer peripheral edge of the circular saw blade 3 attached to the spindle 43 is set large, the contact surface 61A of the circular saw blade 3 is removed. A large cutting depth can be ensured in combination with an increase in the amount of protrusion.

  As shown in FIG. 2, the second long hole 71b is formed in an arc shape with the center O of the rotation support portion 23A as the center, like the first long hole 71a, and the center O of the rotation support portion 23A. On the other hand, it is formed at the outer peripheral position of the first long hole 71a. The above-described screw portion 53 is inserted into the second long hole 71b. Therefore, by fastening the screw part 53, the screw part 53 cannot move in the second long hole 71b with respect to the supported part 71. When the screw portion 53 becomes immovable with respect to the supported portion 71, the split blade mechanism 7 becomes immovable and fixed with respect to the housing 2 to which the screw portion 53 is connected.

  The split blade 72 has substantially the same thickness as that of the circular saw blade 3, is connected to the rear end portion of the supported portion 71, passes through an opening (not shown), and the outer periphery of the circular saw blade 3. The tip of the circular saw blade 3 is arranged slightly above the lowermost portion of the circular saw blade 3. The upper end portion of the split blade 72 is provided with a second spring mounting portion 72A to which the end portion of the spring 22E is attached, and the second spring mounting portion 72A adds a counterclockwise attachment to the safety cover 22B. The power is secured. The place where the spring 22E is mounted is located above the virtual line VL2.

  The connecting portion 73 is disposed above the supported portion 71, and is formed with a third long hole 73a into which the engaging pin 52D is slidably inserted. The third elongated hole 73a is formed in a curved shape that is drilled upward from a position in the vicinity of the rotation support portion 23A and has a central portion protruding forward.

  In the circular saw 1 having the above-described configuration, when cutting wood or the like, the wood 2 is cut and advanced while the housing 2 is brought close to the base portion 6 and the circular saw blade 3 protrudes from the contact surface 61A. At this time, the split blade 72 enters the cut portion of the cut wood, and the circular saw blade 3 is sandwiched by the cut wood and the occurrence of kickback in the circular saw 1 is suppressed.

  Further, sawdust is generated when cutting the wood with the circular saw blade 3, and the sawdust enters the cutting portion from the upper surface of the split blade 72 and the wood, and is clogged between the split blade 72 and the wood, Resistance with the wood increases, and there is a risk that the split blade 72 may become an obstacle when advancing the wood. However, since the fan wind from the fan 25 is guided to the vicinity of the cutting blade 72, the sawdust remaining on the upper surface of the wood is blown off or removed, or as shown in FIG. It is sucked between the circular saw blade 3 and the sawdust is prevented from entering between the split blade 72 and the wood. Therefore, the increase in resistance between the split blade 72 and the wood is prevented, and the wood can be cut and advanced suitably by the circular saw 1.

  The safety cover 22B is disposed between the saw cover main body 22A in which the opening of the air supply passage 23a is formed and the split blade 72, but the safety cover 22B is shown in FIG. 10 at the time of cutting. It turns counterclockwise when viewed from the right side and is located on the top surface of the wood. In this state, a gap is formed between the safety cover 22 </ b> B and the upper surface of the wood, so that the fan air discharged from the air supply passage 23 a through the gap is blown near the split blade 72.

  Further, as described above, since the protruding amount of the circular saw blade 3 from the contact surface 61A can be taken large, even if the small-diameter circular saw blade 3 is used, thick wood can be cut. . Therefore, even if the circular saw 1 is reduced in size, the cutting ability similar to that of the conventional round can be obtained.

  When the cutting depth is changed, the knob 53A is operated to release the fitting state between the screw portion 53, the link 52B, and the supported portion 71, and as shown in FIG. 2 is swung so as to move upward from the state of FIG. Thereby, the protrusion amount from the contact surface 61A of the circular saw blade 3 decreases to L2. Since the split blade mechanism 7 is provided in the housing 2, it moves upward as the housing 2 swings upward, and the amount of protrusion of the split blade 72 from the contact surface 61A is also reduced. However, since the engaging pin 52D of the link 52B is engaged with the third elongated hole 73a of the connecting portion 73, a force in a direction against the upward swing of the housing 2 is transmitted to the split blade mechanism 7, and this The split blade mechanism 7 rotates counterclockwise around the rotation support portion 23 </ b> A with the force in the countering direction as viewed from the left. By this rotation, the split blade 72 moves so as to protrude from the contact surface 61A. Therefore, when the housing 2 is moved upward with respect to the base portion 6 in order to change the cutting depth, the protruding amount of the split blade 72 does not decrease excessively, and the tip of the split blade 72 is a circular saw blade 3. The circular saw blade 3 can be prevented from being always pinched by the wood at the cutting site.

  Further, by reducing the cutting depth, the protruding amount of the circular saw blade 3 protruding from the base portion 6 to be covered by the safety cover 22B is also reduced. The safety cover 22B is held by the split blade mechanism 7 with a spring 22E, but the split blade mechanism 7 reduces the protruding amount from the base portion 6 as the protruding amount of the circular saw blade 3 decreases. Similarly, the safety cover 22B is also pulled by the split blade mechanism 7 via the spring 22E, and the amount protruding from the base portion 6 is reduced, so that the circular saw blade 3 can always be properly protected. Further, as shown in FIG. 10, when the safety cover 22B is rotated around the rotation support portion 23A, the first spring mounting portion 22H is similarly rotated. In this state, the first spring mounting portion 22H is also rotated. Is positioned above the imaginary line VL2, so that the protruding amount of the circular saw blade 3 from the base portion 6 can be kept at the same protruding amount as before the safety cover 22B is rotated.

  The portable cutting machine of the present invention is not limited to the above-described embodiment, and various improvements and modifications can be made within the scope described in the claims. For example, fan air is sent from the lower side of the safety cover 22B positioned between the air supply passage 23a to the split blade 72, but instead of this, as shown in FIG. 11, a plurality of guides are provided to the safety cover 22B. The hole 22b may be formed. The guide hole 22b is arranged so as to be positioned on a straight line connecting the split blade 72 from the air supply passage 23a in a state where the safety cover 22B is rotated when cutting wood or the like. By adopting such a configuration, the fan wind can be discharged toward the split blade 72 more suitably.

  The split blade mechanism 7 is provided with an arc-shaped third elongated hole 73a and the saw cover main body 22A of the housing 2 is provided with a support pin 22C. Conversely, the split blade mechanism is provided with an instruction pin, and the housing 2 is provided with a third long hole. You may take the structure which forms a hole. The indicator pin does not necessarily have a large head, and may be a pin having a constant diameter. In addition, the screw portion 53 is used for fixing the housing 2 to the link portion 52 and the split blade mechanism 7, but the present invention is not limited to this, for example, in the long hole 52a of the link 52B and the second long hole 71b of the supported portion 71. Thus, a rotating cam may be used. By rotating the cam, friction is generated between the cam and the inner periphery of the link 52B that defines the long hole 52a, and the inner periphery of the supported portion 71 that defines the cam and the second long hole 71b. By making the cam non-slidable in the long hole 52a and the second long hole 71b, the housing 2, the link portion 52, and the split blade mechanism 7 can be fixed.

The top view of the portable cutting machine concerning embodiment of this invention. Sectional drawing along the II-II line of FIG. Sectional drawing in the state which looked at the portable cutting machine concerning embodiment of this invention from the front. The fragmentary plane sectional view of the periphery of the saw cover of the portable cutting machine concerning embodiment of this invention. The side view which shows the support pin of the portable cutting machine concerning embodiment of this invention. Sectional drawing which shows the gear mechanism of the portable cutting machine concerning embodiment of this invention. The expanded side view of the spindle periphery of the portable cutting machine concerning embodiment of this invention. The side surface enlarged view which showed the relationship between the split blade and the circular saw blade at the time of the cutting | disconnection of the portable cutting machine concerning embodiment of this invention. The side view in the state where the cutting depth of the portable cutting machine concerning an embodiment of the invention was made shallow. Sectional drawing along the II-II line | wire of FIG. 1 in the state which the safety cover rotated. The side view which concerns on the modification of the portable cutting machine concerning embodiment of this invention.

Explanation of symbols

1. ・ Circular saw 2. ・ Housing 3. ・ Circular saw blade 4. ・ Gear mechanism 5. ・ Projection change mechanism 6. ・ Base part 7. ・ Blade mechanism 21. ・ Motor housing part 21A ・ ・ Handle 21a・ ・ Inlet 22 ・ ・ Saw cover 22A ・ ・ Saw cover body 22B ・ ・ Safety cover 22C ・ ・ Support pin 22D ・ ・ Connector 22E ・ ・ Spring 22F ・ ・ Head 22G ・ ・ Shaft 22H ・ ・ First spring mounted Portion 22b ··· Guide hole 23 · · Gear housing portion 23A · · · Turning support portion 23B · · Circumferential surface 23C · · · rib 23a · · air supply passage 24 · · motor 24A · · output shaft portion 24B · · pinion gear 25 · · Fan 31 · · Bolt 32 · · Flange 41 · · Intermediate gear 41A · · First intermediate gear 41B · · Second intermediate gear 42 · · Final gear 43 · · Spindle 51 · · Swing support 51A · · Base 51B ... Shaft 51C ... Second knob 52 ... Link 52A ... Base 52B ... Link 52C ... First knob 52D ... Engagement pin 52a ... Long hole 53 ... Screw 53A ... Knob 61 ·· Base member 61A · · Contact surface 62 · · First bevel plate 62A · · First tilting shaft portion 63 · · Second bevel plate 63A · · Second tilting shaft portion 71 · · Supported portion 71A · First contact portion 71B Second contact portion 71a First long hole 71b Second long hole 72 Split blade 72A Second spring mounting portion 73 Connection portion 73a Three long holes

Claims (13)

A motor with an output shaft,
A spindle connected to the output shaft portion and fixed so that a cutting blade for cutting a workpiece is coaxially and integrally rotatable;
A housing provided with a saw cover for holding the cutting blade and covering substantially half of the outer periphery of the cutting blade;
A base that is connected to the housing and has an opening formed to project the cutting blade from a contact surface that contacts the processing member;
A protrusion amount changing mechanism capable of changing the protrusion amount of the cutting blade from the opening;
A split blade mechanism having a supported portion provided on the housing and supported around the spindle; and a split blade positioned on the rear side of the cutting blade in the cutting direction of the cutting blade and projecting from a corresponding contact surface; With
The output shaft portion is arranged such that the shaft of the output shaft portion is parallel to the axis of the cutting blade and a pinion gear is provided at the tip.
The spindle is provided with a final gear that rotates coaxially and integrally,
Between the final gear and the pinion gear, an intermediate gear that meshes with the final gear and the pinion gear and rotates on an axis parallel to the axis of the output shaft portion is provided.
The housing includes a rotation support portion having a circumferential surface that rotatably supports the split blade mechanism around the spindle,
When the amount of protrusion from the opening of the cutting blade is set to the maximum, the supported portion is supported by the rotation support portion other than the peripheral portion on the most base side of the rotation support portion ,
The protrusion amount converting mechanism includes a swing support portion including a swing shaft portion provided in front of the cutting blade and parallel to the spindle, and a link portion provided on the rear side of the cutting blade with respect to the spindle. With
The split blade mechanism further includes a connection portion connected to the link portion. The connection portion is interlocked with the link portion, and the housing swings when the housing swings with respect to the base. Rotating the split blade mechanism around the rotation support portion in a direction opposite to the direction,
The supported portion has a virtual axis that hangs down from the corresponding contact surface to the central axis of the rotation support portion in a state where the housing is closest to the base and intersects the circumferential surface of the rotation support portion. For the imaginary line passing through the point and parallel to the corresponding tangent surface, the peripheral edge closest to the base of the supported part is substantially coincident with the imaginary line or located on the opposite base side,
The portable section has a contact portion that contacts the circumferential surface within a range of 180 ° or less around the central axis of the rotation support portion around the rotation support portion. Machine. One of the housing and the split blade mechanism is provided with an arc-shaped portion having an arc shape centering on the central axis of the rotation support portion, and the other of the housing and the split blade mechanism is provided. 2. An engaging portion that engages with the arc-shaped portion and restricts movement of the split blade mechanism other than the movement along the arc-shaped portion with respect to the housing is provided. The portable cutting machine as described. The contact portion has at least a front end side contact portion positioned on the rotation direction side with respect to the rotation support portion and a rear side contact portion positioned on the counter rotation direction side,
2. An imaginary straight line connecting the engagement portion from the central axis of the rotation support portion is located between the front end side contact portion and the rear side contact portion. Or the portable cutting machine in any one of Claim 2. 4. The portable cutting device according to claim 3, wherein the supported portion is supported by the rotation support portion by at least the front end side contact portion, the rear side contact portion, and the engagement portion. Machine. The portable cutting machine according to any one of claims 2 to 4, wherein the engaging portion includes a pin that can be engaged with the arc-shaped portion. The engaging portion has a shaft portion inserted into the arc-shaped portion and a head portion having a diameter larger than that of the shaft portion, and the head portion is larger than a diameter dimension of the arc-shaped portion. The portable cutting machine according to any one of claims 2 to 5. A protective cover that covers a portion protruding from the corresponding contact surface of the base of the cutting blade and is rotatably supported by the rotation support portion;
An elastic body for maintaining the protective cover in a predetermined position;
One end side of the elastic body is provided in the vicinity of the rotation support portion of the protective cover, and the other end side is provided in the vicinity of the counter rotation support portion of the split blade mechanism and in the vicinity of the attachment position of the split blade. The portable cutting machine according to any one of claims 1 to 6, wherein the portable cutting machine is characterized in that: The one end side of the elastic body is substantially coincident with the imaginary line or positioned on the side opposite to the base when the protective cover rotates most about the rotation support portion. The portable cutting machine according to 7. A fan that is provided on the output shaft and rotates coaxially with the output shaft to generate a fan wind;
The cutting blade is fixed to the spindle so as to be coaxially and integrally rotatable,
The portable cutting machine according to claim 1, wherein the fan wind is discharged toward the split blade. The housing has a motor housing that holds the motor and incorporates the fan;
The split blade is provided through the opening,
10. The portable device according to claim 9, wherein the housing is formed with an air supply passage that opens in the vicinity of the opening and in the vicinity of the split blade in the saw cover and opens in the motor housing. Cutting machine. A protective cover that is rotatably supported by the rotating shaft of the cutting blade and covers a portion of the cutting blade that protrudes from the opening of the base;
11. The portable device according to claim 9, wherein a guide hole for guiding the fan air to the split blade is formed on a side surface of the protective cover on the motor side. Cutting machine. The portable cutting machine according to any one of claims 9 to 11, wherein a rectifying plate that is inclined toward the split blade is provided in the air supply passage. 12. The guide hole according to claim 11, wherein at least a part of the guide hole is positioned between the air supply passage and the split blade when the protective cover is rotated around the rotation shaft in the saw cover. The portable cutting machine as described.

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