Work machine

Abstract

The present invention contributes to improvement of convenience. In a chain saw 1, a tension adjustment mechanism 80 is configured to be switchable to a biasing state in which a guide bar 50 is biased to the front side or a non-biasing state in which the guide bar 50 is not biased, and the tension of a saw chain 52 is adjusted by the tension adjustment mechanism 80 in the biasing state. The tension adjustment mechanism 80 is provided on a side cover 60. Specifically, the tension adjustment mechanism 80 is disposed on the rear side of a cover fixing part 61 of the side cover 60 and a fastening member 70. Therefore, the tension adjusting mechanism 80 can be disposed by effectively utilizing the rear side of the cover fixing part 61 and the fastening member 70. As a result, the tension adjustment mechanism 80 can be provided on the chain saw 1 while suppressing an increase in the size of the entire chain saw 1 in the lateral direction. Therefore, even when the tension adjustment mechanism 80 is provided, it is possible to suppress the increase in the size of the chain saw 1, and contribute to improvement of the convenience of the chain saw 1.

Description

Work equipment

[0001] The present invention relates to a work machine.

[0002] The work machine disclosed in Patent Document 1 below has a tension adjustment mechanism that adjusts the tension of a saw chain. Specifically, a motor case is housed inside a main housing so as to be movable forward and backward. A motor is supported in the motor case, and a sprocket is mounted on the motor's rotary shaft so as to be integrally rotatable. A spring is also provided in the main housing, and the spring biases the motor case rearward. This applies a biasing force of the spring to the saw chain wound around the sprocket, thereby adjusting the tension of the saw chain.

[0003] JP 2022-11393 A

[0004] However, in the above-mentioned work machine, the tension adjustment mechanism is provided inside the main body (main body housing) of the work machine. Therefore, depending on the location of the tension adjustment mechanism in the main body, the size of the main body may increase. On the other hand, in the case of portable work machines such as chainsaws, if the size of the work machine increases, the convenience of the work machine may decrease. For this reason, it is desirable to have a structure for work machines such as chainsaws that suppresses the increase in size and contributes to improving the convenience of the work machine.

[0005] In consideration of the above, an object of the present invention is to provide a work machine that can contribute to improving convenience.

[0006] One or more embodiments of the present invention are a work machine comprising: a motor; a main body supporting the motor; a guide attached to the main body so as to be movable in a first direction; a rotating part provided on one side of the guide in the first direction and rotated by the driving force of the motor; a saw chain stretched between the outer periphery of the rotating part and the outer periphery of the guide; a cover detachably attached to the main body, covering the rotating part and part of the saw chain, and attaching to the main body to fix the guide to the main body; and a tension adjustment mechanism provided on the cover and configured to be switchable between an energized state in which the guide is energized to the other side in the first direction and an unenergized state in which the guide is not energized.

[0007] In one or more embodiments of the present invention, the cover has a cover fixing portion fixed to the main body portion and a fastening member that fastens the cover fixing portion to the main body portion, and the tension adjustment mechanism is arranged on one side of the cover fixing portion and the fastening member in the first direction.

[0008] In one or more embodiments of the present invention, the tension adjustment mechanism is attached to the cover so as to be movable in the first direction, and includes a movable member that abuts against the guide portion to apply a biasing force to the guide portion, a biasing member that biases the movable member toward the other side in the first direction, and a switching member connected to the movable member, and in the non-biased state, the movement of the movable member toward the other side in the first direction is restricted by the switching member when the movable member is not abutting against the guide portion, and in the biased state, the switching member's restriction on the movement of the movable member is released.

[0009] One or more embodiments of the present invention are a work machine in which the switching member is configured to be able to engage with the cover, and in the non-actuated state, the switching member engages with the cover to prevent the movable member from moving to the other side in the first direction, and in the actuated state, the switching member is disengaged from the cover to allow the movable member to move to the other side in the first direction.

[0010] In one or more embodiments of the present invention, the switching member is connected to the moving member so as to be rotatable relative to the moving member with a second direction perpendicular to the first direction as the axial direction, and when the switching member is in an engagement position with the cover in the first direction, the switching member rotates relative to the moving member, thereby switching between an engaged state in which the switching member engages with the cover and a disengaged state in which the engagement of the switching member with the cover is released.

[0011] One or more embodiments of the present invention are a work machine in which the guide portion extends in the first direction, and in the non-energized state, the movable member is positioned at a distance from the guide portion to one side in the first direction, and in the energized state, the movable member abuts against the one end of the guide portion in the first direction from one side in the first direction.

[0012] One or more embodiments of the present invention are directed to a work machine in which the tension adjustment mechanism overlaps the rotating part when viewed in the axial direction of the rotating part.

[0013] One or more embodiments of the present invention are a work machine comprising: a motor; a main body supporting the motor; a guide attached to the main body so as to be movable in a first direction; a rotating part provided on one side of the guide in the first direction and rotated by the driving force of the motor; a saw chain stretched between the outer periphery of the rotating part and the outer periphery of the guide; a cover detachably attached to the main body, covering the rotating part and part of the saw chain, and attaching to the main body to fix the guide part to the main body; and a tension adjustment mechanism provided on the cover, which urges the guide part toward the other side in the first direction, wherein the tension adjustment mechanism overlaps the rotating part when viewed in the axial direction of the rotating part.

[0014] One or more embodiments of the present invention can contribute to improved convenience.

[0015] 1 is a side view of the chainsaw according to the present embodiment, as seen from the left side. 2 is a plan view of the chainsaw shown in FIG. 1, as seen from above. 3 is a perspective view of the chainsaw shown in FIG. 1, as seen from the left rear. 4 is a side view of the inside of the chainsaw shown in FIG. 1, as seen from the right side. 5 is a cross-sectional view (cross-sectional view taken along line 5-5 in FIG. 1) of the inside of the chainsaw shown in FIG. 1, as seen from below. 6 is a side view of the front end of the chainsaw body shown in FIG. 1, with the side cover removed. 7 is a side view showing an enlarged view of the area around the upper handle shown in FIG. 1. 8 is a side view of the side cover shown in FIG. 1, as seen from the right side, with the plate cover of the tension adjustment mechanism removed. 9 is a cross-sectional view (cross-sectional view taken along line 9-9 in FIG. 1) of the vertical intermediate portion of the side cover shown in FIG. 1, as seen from below. 10 is a cross-sectional view corresponding to FIG. 9, illustrating the procedure for attaching the guide bar to the chainsaw body. 11 is a cross-sectional view showing the state in which the mounting bolt shown in FIG. 10 has been inserted into the mounting groove of the guide bar. 12 is a cross-sectional view showing the state in which the switching lever shown in FIG. 11 has been rotated relative to the pressure plate, thereby releasing the engagement between the switching lever and the side cover.

[0016] A chainsaw 1 as a work machine according to this embodiment will be described below with reference to the drawings. Note that the arrows UP, FR, and LH shown in the drawings indicate the upper side, front side, and left side of the chainsaw 1, respectively. In the following description, when the up-down, front-rear, and left-right directions are used, they refer to the up-down direction, front-rear direction, and left-right direction of the chainsaw 1 unless otherwise specified. The front-rear direction corresponds to the first direction in the present invention, and the up-down direction corresponds to the second direction in the present invention.

[0017] As shown in Figures 1 to 3, the chainsaw 1 is an electric power tool used to cut a workpiece. The chainsaw 1 has a chainsaw body 10 as a main body, a battery 48, a guide bar 50 as a guide, and a side cover 60 as a cover. The battery 48 is detachably attached to the chainsaw body 10. The chainsaw 1 also has a tension adjustment mechanism 80 (see Figures 7 and 8), which adjusts the tension of the saw chain 52 attached to the chainsaw body 10 (in other words, provides an appropriate tension to the saw chain, or provides tension to the saw chain 52 that will prevent the saw chain 52 from falling off the guide bar 50 and will not break the saw chain 52). The configuration of the chainsaw 1 will be described below.

[0018] (Regarding the chainsaw body 10) The chainsaw body 10 has a housing 11, which forms the outer shell of the chainsaw body 10. The housing 11 is formed in a generally long, hollow shape extending in the front-to-rear direction. The housing 11 has a main housing 12 which forms the front portion of the housing 11, a lower handle 15 which serves as a second handle and forms the middle portion of the housing 11 in the front-to-rear direction, and a battery attachment portion 17 which forms the rear end of the housing 11.

[0019] The main body housing 12 is formed in a generally hollow, flat shape with its thickness extending in the left-right direction. The lower portion (or front portion) of the main body housing 12 is a gear housing portion 13, and the upper portion (or rear portion) of the main body housing 12 is a motor housing portion 14. The motor housing portion 14 protrudes obliquely upward and rearward from the gear housing portion 13. More specifically, as shown in FIGS. 4 and 7 , the motor housing portion 14 is formed in a concave shape that opens obliquely downward and forward in a side cross-sectional view taken from the left-right direction (a predetermined direction), and the upper end of the motor housing portion 14 protrudes above the gear housing portion 13. The motor housing portion 14 has an upper corner 14A (see FIG. 7 ) that protrudes upward in side view, and the upper corner 14A constitutes the upper end of the motor housing portion 14 and the main body housing 12. The motor housing 14 also has a front upper wall 14B located in front of the upper corner 14A and a rear upper wall 14C serving as a cover wall located behind the upper corner 14A. In a side view, the front upper wall 14B extends in a direction that slopes downward toward the front, and the rear upper wall 14C extends in a direction that slopes downward toward the rear. The front end of the front upper wall 14B is bent upward and connected to the upper wall of the gear housing 13.

[0020] An upper handle 20 serving as a first handle and including a front upper wall 14B is provided on the main housing 12. When performing cutting using the chainsaw 1, the operator places one hand (in this embodiment, the left hand) on the upper handle 20 from above and grips the upper handle 20. The configuration of the upper handle 20 will be described later.

[0021] As shown in Figures 4 and 5, the motor housing portion 14 accommodates a motor 30, which is a brushless motor. The motor 30 has an output shaft 30A, which extends in a direction that slopes forward as it extends downward when viewed from the left and right. An upper end of the output shaft 30A is rotatably supported by a motor bearing 31, and a lower end portion of the output shaft 30A is rotatably supported by a motor bearing 32. The motor bearings 31 and 32 are fixed to the motor housing portion 14. As a result, the rear upper wall 14C covers the motor 30 from one axial side (diagonally upward rear side), and the front upper wall 14B covers the motor 30 from the radially outer side.

[0022] A fan 33 is provided at the lower end of the output shaft 30A so as to rotate integrally therewith. The rotation of the fan 33 together with the output shaft 30A generates an airflow within the motor housing portion 14. Specifically, the rotation of the fan 33 causes an airflow to flow into the motor housing portion 14 through side air intakes 14D (see FIGS. 1 to 3) formed in the side wall of the motor housing portion 14, thereby cooling the motor 30. A bevel gear 34 serving as a power transmission portion is provided at the lower end of the output shaft 30A so as to rotate integrally therewith.

[0023] A rotating shaft 35 is provided in the gear housing 13 on the other axial side of the motor 30, and the rotating shaft 35 is disposed with its axis aligned in the left-right direction. A left portion of the rotating shaft 35 is rotatably supported by a bearing 36, and a right portion of the rotating shaft 35 is rotatably supported by a bearing 37. The bearing 36 is fixed to the gear housing 13, and the bearing 37 is fixed to a holder member 38 provided within the gear housing 13. A bevel gear 39 is provided at an axially intermediate portion of the rotating shaft 35 so as to rotate integrally therewith, and the bevel gear 39 meshes with the bevel gear 34 of the motor 30. As shown in FIG. 6 , the left end of the rotating shaft 35 protrudes leftward from the gear housing 13, and a sprocket 40 serving as a rotating part is provided at the left end of the rotating shaft 35 so as to rotate integrally therewith. As a result, the sprocket 40 rotates together with the rotating shaft 35 when the motor 30 is driven.

[0024] The gear housing 13 is provided with a mounting bolt 41, the axial direction of which is the left-right direction, on the front side of the sprocket 40. The right end of the mounting bolt 41 is fixed to the gear housing 13, and the left part of the mounting bolt 41 protrudes to the left from the gear housing 13. A male thread is formed on the outer periphery of the left end of the mounting bolt 41. The gear housing 13 is also provided with a pair of front and rear guide shafts 42 on both front-rear sides of the mounting bolt 41, and the guide shafts 42 are arranged with their axial direction aligned with the left-right direction. The guide shafts 42 are embedded in the gear housing 13, and the left end of the guide shaft 42 protrudes to the left from the gear housing 13.

[0025] As shown in FIGS. 1 to 4 , the lower handle 15 is formed in a hollow column shape and extends rearward from the rear of the vertically middle portion of the gear housing portion 13. Specifically, the lower handle 15 is positioned below the rear upper wall 14C and is slightly tilted downward toward the rear in side view. That is, in side view, the handle center line 15A (see FIG. 1 ) of the lower handle 15 extends in a direction that tilts downward toward the rear. The upper outer periphery of the lower handle 15 is covered with a rubber portion 16 (see the gray area in FIGS. 1 and 2 ). The rubber portion 16 is made of an elastic material such as rubber or elastomer. The rubber portion 16 extends toward the main housing 12 and covers a portion of the main housing 12, and the surface of the upper handle 20 (described later) is formed by the rubber portion 16.

[0026] A controller 43 is housed in the rear of the lower handle 15, and the motor 30 is electrically connected to the controller 43. A trigger 44 serving as an operating unit is provided at the front end of the lower handle 15. The trigger 44 protrudes downward from the lower handle 15 and can be pulled upward. A switch 45 is provided inside the lower handle 15, above the rear end of the trigger 44, and the switch 45 is electrically connected to the controller 43. During cutting, the operator holds the lower handle 15 with his other hand (right hand) and pulls the trigger 44 with the fingers of the holding hand. When the trigger 44 is pulled, the trigger 44 presses the switch 45, and the switch 45 outputs an ON signal to the controller 43.

[0027] An off-lock button 46 is provided on the gear housing portion 13 at the boundary with the lower handle 15, and the off-lock button 46 protrudes to both the left and right from the rear of the main body housing 12. The off-lock button 46 is provided above the trigger 44 so as to prevent the trigger 44 from being pulled. By pushing the off-lock button 46 to the right or left, the trigger 44 can be pulled.

[0028] The battery mounting portion 17 protrudes upward and downward and left and right from the lower handle 15. The battery mounting portion 17 and the lower handle 15 are smoothly connected by a connecting portion 18. A handle guard 19 is provided below the lower handle 15. The handle guard 19 extends substantially parallel to the lower handle 15 in a side view, with the front end of the handle guard 19 connected to the lower end of the main body housing 12 and the rear end of the handle guard 19 connected to the battery mounting portion 17. A terminal unit 47 is provided in the battery mounting portion 17 and is electrically connected to the controller 43. A battery 48 is detachably attached to the battery mounting portion 17 and connected to the terminal unit 47. This electrically connects the battery 48 to the controller 43, and power is supplied from the battery 48 to the motor 30 and the controller 43.

[0029] (Regarding the Guide Bar 50) As shown in Figures 1, 3, and 5 to 8, the guide bar 50 is formed as a generally elongated plate with its thickness extending in the left-right direction and its length extending in the front-to-rear direction. A mounting groove 50A (see Figure 6) is formed in the center of the rear end of the guide bar 50 in the up-down direction. The mounting groove 50A is formed as a groove extending in the front-to-rear direction and penetrates the guide bar 50 in the left-to-right direction, with the rear end of the mounting groove 50A open to the rear. The mounting bolt 41 and guide shaft 42 are inserted into the mounting groove 50A of the guide bar 50, and the rear end of the guide bar 50 is attached to the chainsaw body 10 at the front left side of the gear housing 13 and in front of the sprocket 40 so as to be relatively movable in the front-to-rear direction. In other words, the guide bar 50 is attached to the chainsaw body 10 so as to be able to move toward and away from the sprocket 40. The guide bar 50 is fixed to the chainsaw body 10 by a side cover 60 and a fastening member 70, which will be described later, in a state in which it extends forward from the front of the gear housing portion 13.

[0030] The portion of the rear end of the guide bar 50 below the mounting groove 50A is a pressed portion 50B (see FIG. 6 ). The pressed portion 50B is located rearward and below the mounting bolt 41. A tension adjustment mechanism 80 (described later) presses the pressed portion 50B forward, thereby urging the guide bar 50 forward and adjusting the tension of the saw chain 52 (described later).

[0031] An endless saw chain 52 serving as a tool tip is wound around the outer periphery of the sprocket 40 and the guide bar 50. Therefore, when the sprocket 40 is rotated by the drive of the motor 30, the saw chain 52 rotates in one circumferential direction along the outer periphery of the guide bar 50. This causes cutting to be performed on a workpiece located below the front portion of the saw chain 52. In other words, the lower end of the outer periphery of the saw chain 52 serves as a cutting section 52A (see FIG. 1 ) that cuts the workpiece. In other words, the saw chain 52 is fixed to the chainsaw body 10, extending forward together with the guide bar 50 from the front portion of the gear housing 13.

[0032] 1 , the vertical position of the lower handle 15 relative to the saw chain 52 is set so that, in a side view, an overhead wire OL that passes through the processing portion 52A of the saw chain 52 and extends in the front-to-rear direction passes through the center portion 15B of the lower handle 15. Note that the center portion 15B of the lower handle 15 in a side view is the intersection of the longitudinal center of the lower handle 15 and the handle center line 15A. Here, the front end 15F of the lower handle 15 is a portion adjacent to the rear side of the off-lock button 46, and the rear end 15R of the lower handle 15 is a portion adjacent to the front side of the connection portion 18.

[0033] (Regarding the side cover 60) As shown in Figures 1 to 3, 5, 8, and 9, the side cover 60 covers the rear of the sprocket 40 and the guide bar 50 from the left side, and is fixed to the chainsaw body 10 together with the guide bar 50 by a fastening member 70.

[0034] The side cover 60 is generally formed in a generally concave shape that opens to the right and front. A vertically intermediate portion of the front end of the side cover 60 defines a cover fixing portion 61, and a fastening member 70 (described later) is disposed in the cover fixing portion 61. A metal bushing 65 (see FIGS. 5 and 8 ) is embedded in the cover fixing portion 61, and the bushing 65 is integrally formed with the side cover 60 by insert molding or other techniques. The mounting bolt 41 is inserted through the bushing 65, and the side cover 60 is disposed on the left side of the gear housing portion 13. The fastening member 70 is threadedly engaged with the tip of the mounting bolt 41 to fasten the side cover 60, thereby fastening the side cover 60 together with the guide bar 50 to the chainsaw body 10. The fastening member 70 includes a generally disc-shaped base portion 71 whose thickness is in the left-right direction and a nut 72 embedded in the center of the base portion 71, and the nut 72 is threadedly engaged with the mounting bolt 41. A clamping lever 73 is provided on the base portion 71, and the clamping lever 73 is rotatably connected to the base portion 71 with the vertical direction as its axial direction.

[0035] As described above, the side cover 60 is removably attached to the main housing 12. When the side cover 60 is attached to the main housing 12, the sprocket 40 and the rear portion of the guide bar 50 are housed inside the side cover 60 (see FIG. 8). In other words, the side cover 60 defines a storage space for accommodating the sprocket 40.

[0036] As shown in FIGS. 1 and 9 , a lever housing 62 for housing a switching lever 87 (described later) is formed on the outer periphery (left side surface) of the rear portion of the side cover 60. The lever housing 62 is formed in a concave shape that opens to the left and extends in the front-to-rear direction. An inclined bottom surface 62A is formed on the front bottom surface of the lever housing 62, and in a cross-sectional view from below, the inclined bottom surface 62A slopes to the right as it approaches the rear. An engagement hook 62B is formed on the rear bottom surface of the lever housing 62 as an engagement portion that constitutes part of the tension adjustment mechanism 80 (described later). In a cross-sectional view from below, the engagement hook 62B has a wedge shape. Specifically, in a cross-sectional view from below, the engagement hook 62B has a hook inclined surface 62B1 that slopes to the left as it approaches the rear, and an engagement surface 62B2 that extends to the right from the rear end of the hook inclined surface 62B1.

[0037] 8 and 9 , a plate accommodating portion 63 for accommodating a pressure plate 82 (described later) is formed on the inner peripheral portion of the rear of the side cover 60. The plate accommodating portion 63 is formed in a generally rectangular recessed shape with its longitudinal direction extending in the front-to-rear direction and open to the right, and protrudes to the right from the inner peripheral surface of the side cover 60. The lever accommodating portion 62 described above is located on the left side of the lower portion of the plate accommodating portion 63, and the lever accommodating portion 62 and the plate accommodating portion 63 are separated by the bottom wall of the lever accommodating portion 62. A communication hole 62C is formed through the bottom wall of the lever accommodating portion 62 between the inclined bottom surface 62A and the engaging hook 62B, and the communication hole 62C connects the lever accommodating portion 62 and the lower portion of the plate accommodating portion 63.

[0038] A spring accommodating portion 63A is formed in the upper portion of the plate accommodating portion 63 to accommodate a biasing spring 83 (described later). The spring accommodating portion 63A is formed in a recessed shape extending in the front-rear direction and opening to the right, thereby dividing the spring accommodating portion 63A and the lower portion of the plate accommodating portion 63 into upper and lower sections. A stepped portion 63B is formed on the inner surface of the peripheral wall of the plate accommodating portion 63, protruding inward. The stepped portion 63B extends in the circumferential direction of the plate accommodating portion 63 and is positioned one step lower to the left of the open end of the plate accommodating portion 63. A pair of front and rear fixing holes 63C are formed in the upper portion of the stepped portion 63B, and the fixing holes 63C are formed in a recessed shape opening to the right. An extended accommodating portion 63D is formed in the front end of the peripheral wall of the plate accommodating portion 63 at a vertically intermediate portion, protruding forward. The extended accommodating portion 63D extends the plate accommodating portion 63 forward.

[0039] (Regarding the Upper Handle 20) As shown in FIGS. 1 to 4 and 7 , the upper handle 20 forms the upper end of the chainsaw 1 and the main housing 12 and extends in the front-to-rear direction. The upper handle 20 includes a main handle portion 21 serving as a main grip forming the front portion of the upper handle 20, and an extension handle portion 22 serving as an extension grip forming the rear portion of the upper handle 20. The main handle portion 21 is formed by the front upper wall 14B of the motor housing portion 14 and the upper ends of the left and right side walls of the motor housing portion 14, and has a predetermined thickness when viewed from the left and right. The rubber portion 16 described above covers the motor housing portion 14 so as to form the surface of the main handle portion 21. That is, in this embodiment, the front upper wall 14B, the main handle portion 21, and the extension handle portion 22 are all formed to include the rubber portion 16. The upper surface of the main body side handle portion 21 is a main body side receiving surface 21A, which is configured as a receiving surface that receives the front part of the operator's left hand that is placed on the upper handle 20.

[0040] The extension handle 22 is formed in a generally rectangular plate shape with its thickness in the vertical direction and extending in the front-to-rear direction. It is located rearward of the upper corner 14A of the motor housing 14 and spaced apart above the rear upper wall 14C. In other words, the extension handle 22 extends rearward from the upper end of the rear upper wall 14C and is positioned adjacent to the rear of the main body handle 21. More specifically, the extension handle 22 extends rearward from the outer periphery of the upper end of the motor housing 14 so as not to change the vertical dimension of the main body housing 12. As a result, in a side view, the upper handle 20 is bent upwardly convexly at the boundary between the main body handle 21 and the extension handle 22. The upper surface of the extension handle 22 is an extension receiving surface 22A, which is continuous with the main body receiving surface 21A. In addition, the angle AG formed by the main body side receiving surface 21A (main body side handle portion 21) and the extension receiving surface 22A (extension handle portion 22) is set to an obtuse angle in side view.

[0041] The extended support surface 22A is configured as a support surface that supports the rear of the operator's left hand, which is placed on the upper handle 20. As a result, during cutting, the operator places his or her left hand on the upper handle 20 and grips the upper handle 20. That is, the upper handle 20 utilizes a portion of the upper end portion of the main body housing 12 and extends in the front-to-rear direction so as to straddle the upper end (upper end corner 14A) of the motor housing portion 14. As a result, in the chainsaw 1, the operator directly grips a portion of the main body housing 12. In addition, the upper handle 20 is located above the front end of the lower handle 15 (where the trigger 44 is located).

[0042] When viewed from the left and right, the extension length of the main body receiving surface 21A (main body handle portion 21) is 60 mm or less (46 mm in this embodiment), and the sum of the extension length of the main body receiving surface 21A and the extension length of the extension receiving surface 22A (extension handle portion 22) is 90 mm or more (96 mm in this embodiment). The width dimension (left and right dimension) of the upper handle 20 is set slightly smaller than the thickness dimension of the main body housing 12 (see FIG. 2).

[0043] A barb 23 is integrally formed at the tip (rear end) of the extension handle 22 (upper handle 20). The barb 23 extends downward from the tip of the extension handle 22, and the lower end of the barb 23 is bent diagonally downward and forward to connect to the rear upper wall 14C of the motor housing 14. As a result, in a side view, the chainsaw 1 has a handle hole 24 as a hole surrounded by the rear upper wall 14C (main housing 12), the extension handle 22, and the barb 23. The handle hole 24 penetrates in the left-right direction below the extension handle 22. In addition, a finger hook 25 as a hook is formed on the outer periphery of the housing 11 (main housing 12) at the connection between the barb 23 and the rear upper wall 14C. The finger hook 25 is carved into a generally V-shape that is open to the rear in a side view. That is, a finger hook 25 is formed on the outer periphery of the housing 11 below the upper handle 20. The vertical distance between the finger hook 25 and the upper handle 20 is set so that the operator can hook the operator's thumb FG (see FIG. 7 ) onto the finger hook 25 when gripping the upper handle 20 with his / her left hand.

[0044] A rear air intake port 14E (see FIGS. 3 and 4) serving as an air vent is formed through the rear upper wall 14C of the motor housing portion 14. The rear air intake port 14E connects the handle hole 24 to the interior of the motor housing portion 14. The rear air intake port 14E is formed as an elongated hole with its longitudinal direction extending vertically. This allows air to flow into the motor housing portion 14 from the rear air intake port 14E when the fan 33 is rotating.

[0045] 8 and 9 , the tension adjustment mechanism 80 is configured as a mechanism that biases the guide bar 50 forward to adjust the tension of the saw chain 52. The tension adjustment mechanism 80 is configured to be switchable between a biased state in which the guide bar 50 is biased forward and a non-biased state in which the guide bar 50 is not biased. The tension adjustment mechanism 80 has a biasing mechanism 81 and a switching mechanism 86.

[0046] The biasing mechanism 81 has a pressure plate 82 as a moving member and a biasing spring 83 as a biasing member. The pressure plate 82 has a thickness in the left-right direction and is formed in a generally Y-shaped plate that is open to the rear when viewed from the left-right direction. Specifically, the pressure plate 82 has a front plate portion 82A extending in the front-to-rear direction, a first rear plate portion 82B extending upward and rearward from the rear end of the front plate portion 82A, and a second rear plate portion 82C extending downward and rearward from the rear end of the front plate portion 82A.

[0047] The pressing plate 82 is accommodated in the plate accommodating portion 63 of the side cover 60 so as to be movable in the front-to-rear direction. Specifically, the front plate portion 82A is accommodated in the extended accommodating portion 63D of the plate accommodating portion 63, the first rear plate portion 82B is accommodated in the upper portion of the plate accommodating portion 63, and the second rear plate portion 82C is accommodated in the lower portion of the plate accommodating portion 63.

[0048] A pressing portion 82D is formed at the front end of the front plate portion 82A, bending it to the right, and the tip of the pressing portion 82D is folded back 180 degrees. When the tension adjustment mechanism 80 is in the biased state, the tip of the pressing portion 82D abuts against the pressed portion 50B of the guide bar 50 from the rear, and the biasing force of a biasing spring 83 (described later) presses the pressed portion 50B forward (see the pressing plate 82 indicated by the solid line in FIG. 9 ). When the tension adjustment mechanism 80 is in the unbiased state, the pressing plate 82 is positioned away from the rear of the guide bar 50 by a switching lever 87 (described later), and the pressing portion 82D is released from abutment against the pressed portion 50B (see the pressing portion 82D and switching lever 87 indicated by the two-dot chain line in FIG. 9 ). The positions of the pressure plate 82 and the switching lever 87 when the tension adjustment mechanism 80 is in the non-biased state are referred to as the non-biased positions.

[0049] The rear end of the first rear plate portion 82B is bent to the left and disposed within the spring housing portion 63A of the side cover 60. A biasing spring 83 configured as a compression coil spring is housed within the spring housing portion 63A on the rear side of the first rear plate portion 82B. The front end of the biasing spring 83 is engaged with the rear end of the first rear plate portion 82B, and the rear end of the biasing spring 83 is engaged with the rear surface of the spring housing portion 63A, so that the biasing spring 83 biases the first rear plate portion 82B (pressure plate 82) forward. As a result, when the tension adjustment mechanism 80 is in the biased state and the clamping member 70 is released from clamping against the side cover 60, the biasing spring 83 biases the guide bar 50 forward, thereby adjusting the tension of the saw chain 52.

[0050] The rear end of the second rear plate portion 82C is bent to the left and inserted through the communication hole 62C of the side cover 60, and is disposed within the lever accommodating portion 62 of the side cover 60. A connecting piece 82E bent rearward is formed at the rear end of the second rear plate portion 82C. A connecting hole 82F is formed in the vertical direction through the connecting piece 82E.

[0051] A plate cover 84 is provided in the opening of the plate accommodating portion 63 in the side cover 60, and the plate cover 84 closes the opening, maintaining the pressure plate 82 and the biasing spring 83 housed in the plate accommodating portion 63. The plate cover 84 is formed in a generally rectangular plate shape with its thickness in the left-right direction, and the outer periphery of the plate cover 84 rests on the stepped portion 63B of the plate accommodating portion 63. The lower end of the plate cover 84 engages with the lower wall of the plate accommodating portion 63 by a claw engagement, and the upper end of the plate cover 84 is fastened and fixed to the stepped portion 63B by a fixing screw 85. Specifically, the plate cover 84 has a hole corresponding to the fixing hole 63C of the plate accommodating portion 63, and the fixing screw 85 inserted through the hole is threaded into the fixing hole 63C, fastening and fixing the plate cover 84 to the stepped portion 63B.

[0052] The switching mechanism 86 is composed of a switching lever 87 as a switching member and the aforementioned engagement hook 62B formed on the side cover 60. The switching lever 87 is formed in a generally rectangular recessed shape with its longitudinal direction extending in the left-right direction and open to the right, and is housed in the lever housing 62 of the side cover 60. A lever inclined portion 87A is formed at the front end of the bottom wall (left wall) of the switching lever 87, and the lever inclined portion 87A inclines to the right as it approaches the front in a plan view. A lever recess 87B is formed at the rear end portion of the switching lever 87. The lever recess 87B is open to the left and is formed in the shape of a groove extending in the vertical direction, and penetrates in the vertical direction. The right end of the rear wall of the switching lever 87 serves as a lever engagement portion 87C.

[0053] Three connecting ribs 87D to 87F are formed inside the switching lever 87 at a central portion in the front-to-rear direction. The connecting ribs 87D to 87F have the front-to-rear direction as the plate thickness direction, extend in the up-down direction, and are arranged side by side at a predetermined interval in the front-to-rear direction. Both up-down ends of the front connecting rib 87D are connected to the upper and lower side walls of the switching lever 87. The second connecting rib 87E from the front and the rear connecting rib 87F have their upper ends connected to the upper side wall of the switching lever 87 and their lower ends spaced apart from the lower side wall of the switching lever 87.

[0054] A connecting shaft 88, whose axial direction is the up-down direction, is provided between the connecting ribs 87E and 87F, and the connecting shaft 88 is bridged across the upper and lower side walls of the switching lever 87. The rear end of the second rear plate portion 82C of the pressing plate 82 is disposed between the connecting ribs 87D and 87E, and the connecting piece 82E of the pressing plate 82 is disposed between the connecting ribs 87E and 87F and the lower side wall of the switching lever 87. The connecting shaft 88 is inserted through the connecting hole 82F of the pressing plate 82. As a result, the switching lever 87 is connected to the pressing plate 82 so as to be movable integrally in the front-rear direction, and is also connected to the pressing plate 82 so as to be rotatable about the up-down direction as its axial direction.

[0055] When the tension adjustment mechanism 80 is in the biased state, the front end of the switching lever 87 is positioned adjacent to the left side of the inclined bottom surface 62A of the side cover 60, and the lever engagement portion 87C of the switching lever 87 is positioned adjacent to the left side of the hook inclined surface 62B1 of the engagement hook 62B of the side cover 60. To switch the tension adjustment mechanism 80 from the biased state to the unbiased state, an operator slides the switching lever 87 rearward to engage the lever engagement portion 87C with the engagement hook 62B, thereby switching the tension adjustment mechanism 80 to the unbiased state. Specifically, an operator inserts his or her finger into the lever recess 87B of the switching lever 87 to slide the switching lever 87 to the unbiased position. When the switching lever 87 is in the unbiased position, the lever recess 87B is pushed to the right and the switching lever 87 is rotated relative to the pressure plate 82, whereby the lever engagement portion 87C engages with the engagement surface 62B2 of the engagement hook 62B. As a result, the side cover 60 restricts the forward movement of the switching lever 87, and the tension adjustment mechanism 80 is maintained in a non-biased state.

[0056] On the other hand, when the switching lever 87 is in the non-biased position, pressing the lever inclined portion 87A of the switching lever 87 to the right rotates the switching lever 87 relative to the pressure plate 82, disengaging the lever engaging portion 87C from the engaging hook 62B. As a result, the biasing force of the biasing spring 83 causes the pressure plate 82 and the switching lever 87 to slide forward, and the pressing portion 82D of the pressure plate 82 presses the pressed portion 50B of the guide bar 50 forward. Thus, the tension adjustment mechanism 80 switches from the non-biased state to the biased state.

[0057] The positions of the tension adjustment mechanism 80 in the front-rear and up-down directions are set so that the sprocket 40 and the rear of the tension adjustment mechanism 80 overlap when viewed from the left-right direction (see FIG. 8 ). That is, the tension adjustment mechanism 80 is located behind the cover fixing portion 61 of the side cover 60 and the fastening member 70. Specifically, when viewed from the left-right direction, the tension adjustment mechanism 80 is located inside the outer periphery (blade portion) of the rear of the saw chain 52 wrapped around the sprocket 40. When viewed from the left-right direction, the majority of the tension adjustment mechanism 80 is located below the vertical center of the guide bar 50 and the mounting bolt 41, while the fixing screw 85 that secures the plate cover 84 is located above the vertical center of the guide bar 50. Furthermore, the left-right size of the tension adjustment mechanism 80 (switching lever 87) is set so that the tension adjustment mechanism 80 (switching lever 87) does not protrude to the left of the fastening member 70 (see FIG. 9 ).

[0058] (Operation and Effect) Next, the operation and effect of this embodiment will be described.

[0059] In the chainsaw 1 configured as described above, the operator holds the lower handle 15 with his right hand and the upper handle 20 with his left hand. Then, by pulling the trigger 44, the motor 30 is driven and the sprocket 40 rotates. This causes the saw chain 52 to rotate in the circumferential direction of the guide bar 50, and the rotating saw chain 52 cuts the workpiece.

[0060] Next, a procedure for attaching the guide bar 50 to the main body housing 12 (chainsaw main body 10) will be described.

[0061] 10, when attaching the guide bar 50 to the main housing 12, the guide bar 50 is positioned on the left side of the main housing 12, and the side cover 60 is positioned on the left side of the guide bar 50. At this time, in the tension adjustment mechanism 80, the switching lever 87 is positioned in the non-biased position, and the lever engaging portion 87C of the switching lever 87 and the engaging hook 62B of the side cover 60 are engaged.

[0062] Next, as shown in Figure 11, the guide bar 50 is moved to the right, the mounting bolt 41 is inserted into the mounting groove 50A of the guide bar 50, and the guide bar 50 is positioned adjacent to the left side of the main housing 12. This allows the guide bar 50 to be attached to the main housing 12 in front of the sprocket 40 so that it can move in the front-to-rear direction. The saw chain 52 is then wrapped around the outer periphery of the guide bar 50 and the outer periphery of the sprocket 40 and attached to both. The clamping lever 73 of the clamping member 70 is also rotated relative to the base portion 71 so that it protrudes to the left from the base portion 71.

[0063] Next, the nut 72 of the fastening member 70 is threaded onto the mounting bolt 41 using the fastening lever 73, and the side cover 60 is temporarily fastened by the fastening member 70. In this case, the pressing portion 82D of the pressing plate 82 is positioned rearward and spaced apart from the pressed portion 50B of the guide bar 50. In this state, as shown in FIG. 12 , the lever inclined portion 87A of the switching lever 87 is pressed to the right, causing the switching lever 87 to rotate relative to the pressing plate 82. This disengages the lever engaging portion 87C of the switching lever 87 from the engaging hook 62B of the side cover 60.

[0064] 9, when the engagement between the switching lever 87 and the side cover 60 is released, the pressing plate 82 and switching lever 87 slide forward due to the biasing force of the biasing spring 83, and the pressing portion 82D of the pressing plate 82 abuts against the pressed portion 50B of the guide bar 50 from the rear. As a result, the guide bar 50 is biased forward by the biasing force of the biasing spring 83. Therefore, the saw chain 52 wound around the sprocket 40 and the guide bar 50 is pulled outward in the front-to-rear direction, adjusting the tension of the saw chain 52. After adjusting the tension of the saw chain 52, the side cover 60 is finally tightened by the tightening member 70.

[0065] In the chainsaw 1, the tension adjustment mechanism 80 is configured to be switchable between an energized state in which the guide bar 50 is biased forward and an unenergized state in which the guide bar 50 is not biased. The tension of the saw chain 52 is adjusted by the energized tension adjustment mechanism 80. The tension adjustment mechanism 80 is also provided on the side cover 60. Specifically, the tension adjustment mechanism 80 is disposed behind the cover fixing portion 61 of the side cover 60 and the fastening member 70 that fastens the cover fixing portion 61 to the main body housing 12. This allows the tension adjustment mechanism 80 to be positioned by effectively utilizing the space behind the cover fixing portion 61 and the fastening member 70. As a result, the tension adjustment mechanism 80 can be provided on the chainsaw 1 while preventing the size of the chainsaw 1 from increasing in the left-right direction. Therefore, even with the tension adjustment mechanism 80, the size of the chainsaw 1 can be prevented from increasing, contributing to improved convenience of the chainsaw 1.

[0066] The tension adjustment mechanism 80 includes a pressure plate 82 attached to the side cover 60 so as to be movable in the front-to-rear direction, a biasing spring 83 that biases the pressure plate 82 forward, and a switch lever 87 connected to the pressure plate 82. When the tension adjustment mechanism 80 is in a non-biased state, the forward movement of the pressure plate 82 is restricted by the switch lever 87 when the pressure plate 82 is not in contact with the guide bar 50. On the other hand, when the tension adjustment mechanism 80 is in a biased state, the restriction on the movement of the pressure plate 82 imposed by the switch lever 87 is released. Specifically, when the tension adjustment mechanism 80 is in a non-biased state, the switch lever 87 engages with the engagement hook 62B of the side cover 60, thereby restricting the forward movement of the pressure plate 82 by the switch lever 87. On the other hand, when the engagement of the switch lever 87 with the engagement hook 62B is released, the restriction on the movement of the pressure plate 82 imposed by the switch lever 87 is released. This allows the tension adjustment mechanism 80 to be switched between the biased state and the non-biased state with a simple configuration.

[0067] The switching lever 87 is connected to the pressure plate 82 so as to be movable integrally in the front-to-rear direction, and is also connected to the pressure plate 82 so as to be rotatable about its axis in the up-to-down direction. When the switching lever 87 is in the non-biased position, the switching lever 87 rotates relative to the pressure plate 82, switching the switching lever 87 between an engaged state in which it engages with the engagement hook 62B and a disengaged state in which it is disengaged from the engagement hook 62B. Thus, when the switching lever 87 is in the non-biased position, the tension adjustment mechanism 80 can be switched between an energized state and a non-energized state by rotating the switching lever 87.

[0068] Furthermore, when the tension adjustment mechanism 80 is in a non-biased state, the pressing portion 82D of the pressing plate 82 is positioned rearward and spaced from the pressed portion 50B of the guide bar 50, and when the tension adjustment mechanism 80 is in a biased state, the pressing portion 82D abuts against the pressed portion 50B from the rear. This improves the ease of attaching the side cover 60 to the main body housing 12. That is, for example, if a hole is formed through the guide bar 50 and the pressing portion 82D is configured to be inserted into the hole, it is necessary to align the pressing portion 82D with the hole when inserting the pressing portion 82D into the hole. In contrast, in the present embodiment, the pressing portion 82D is configured to abut from the rear side against the pressed portion 50B, which is the rear end of the guide bar 50. This means that when attaching the side cover 60 to the main body housing 12, the side cover 60 can be attached to the main body housing 12 without aligning the pressing portion 82D with the pressed portion 50B. After temporarily attaching the side cover 60 to the main body housing 12, the tension adjustment mechanism 80 can be switched from a non-biased state to a biased state, allowing the pressing portion 82D to abut against the pressed portion 50B of the guide bar 50. This prevents a decrease in workability when attaching the side cover 60 to the main body housing 12, even when the tension adjustment mechanism 80 is provided on the side cover 60.

[0069] Furthermore, the tension adjustment mechanism 80 overlaps the sprocket 40 when viewed from the left and right. Specifically, the tension adjustment mechanism 80 is located to the left of the sprocket 40, overlaps the sprocket 40 when viewed from the left and right, and is located inside the outer periphery (blade portion) of the saw chain 52 that is wound around the sprocket 40. This allows for an effective positional relationship between the tension adjustment mechanism 80 provided on the side cover 60 and the saw chain 52. That is, the portion of the saw chain 52 that extends in the front-to-rear direction between the sprocket 40 and the guide bar 50 (hereinafter referred to as the unsupported portion) is not supported by the sprocket 40 or the guide bar 50. Therefore, when the chainsaw 1 is in operation, the unsupported portion of the saw chain 52 may vibrate up and down. In particular, the outer periphery (blade portion) of the unsupported portion of the saw chain 52 is likely to vibrate up and down. On the other hand, the portion of the saw chain 52 that is wound around the sprocket 40 is supported by the sprocket 40 and therefore rotates stably even when the chainsaw 1 is in operation. Therefore, even if the tension adjustment mechanism 80 is provided on the side cover 60, by arranging the tension adjustment mechanism 80 in a position that overlaps the sprocket 40 when viewed from the left and right, the tension adjustment mechanism 80 can be arranged in the inner region of the saw chain 52, which rotates in a stable state. Therefore, an effective positional relationship can be achieved between the tension adjustment mechanism 80 provided on the side cover 60 and the saw chain 52.

[0070] Furthermore, most of the tension adjustment mechanism 80 is located below the vertical center of the guide bar 50. Furthermore, in the tension adjustment mechanism 80, the lower end of the plate cover 84 is fixed to the plate housing portion 63 (side cover 60) by a claw engagement, and the upper end of the plate cover 84 is fixed to the plate housing portion 63 (side cover 60) by a fixing screw 85, which is located above the vertical center of the guide bar 50. This also allows for an effective positional relationship between the tension adjustment mechanism 80 provided on the side cover 60 and the saw chain 52. That is, in the chainsaw 1, because cutting is performed on a workpiece located below the saw chain 52, a counterclockwise rotational moment is generated in the guide bar 50 about the mounting bolt 41 when viewed from the right side. Therefore, as work progresses, the guide bar 50 may tilt so that the front end of the guide bar 50 is displaced upward. Therefore, in the tension adjustment mechanism 80, the pressing portion 82D presses the pressed portion 50B below the mounting bolt 41, thereby pressing the guide bar 50 so that a rotational moment similar to that described above is generated during tension adjustment, thereby suppressing tilt of the guide bar 50 during operation. For this reason, as described above, the tension adjustment mechanism 80 is primarily positioned below the vertical center of the guide bar 50. If the positional relationship between the fixing screw 85 that secures the plate cover 84 and the claw engagement were reversed up and down in the tension adjustment mechanism 80, the fixing screw 85 could overlap the outer periphery of an unstable portion of the saw chain 52 when viewed from the left and right. In contrast, in this embodiment, as described above, the fastening portion for the fixing screw 85, which requires a relatively large space, is located at the upper end of the plate cover 84. This allows the tension adjustment mechanism 80 to overlap the sprocket 40 in a side view and be positioned inside the outer periphery (blade portion) of the saw chain 52 wrapped around the sprocket 40. Therefore, from this point of view as well, an effective positional relationship between the tension adjustment mechanism 80 provided on the side cover 60 and the saw chain 52 can be realized.

[0071] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0072] 1... Chainsaw (working machine), 10... Chainsaw body (body part), 30... Motor, 40... Sprocket (rotating part), 50... Guide bar (guiding part), 52... Saw chain (tip tool), 60... Side cover (cover), 61... Cover fixing part, 70... Fastening member, 80... Tension adjustment mechanism, 82... Pressing plate (moving member), 83... Spring (spring member), 87... Switching lever (switching member)

Claims

1. A working machine comprising: a motor; a main body portion that supports the motor; a guide portion that is attached to the main body portion so as to be movable in a first direction; a rotating portion that is provided on one side of the guide portion in the first direction and rotates by the driving force of the motor; a sorption member that spans between the outer peripheral portion of the rotating portion and the outer peripheral portion of the guide portion; a cover that is detachably attached to the main body portion, covers a part of the rotating portion and the sorption member, and fixes the guide portion to the main body portion by being attached to the main body portion; and a tension adjustment mechanism that is provided on the cover and is configured to be switchable between a biasing state in which the guide portion is biased to the other side in the first direction and a non-biasing state in which the guide portion is not biased.

2. The working machine according to claim 1, wherein the cover has a cover fixing portion fixed to the main body portion and a fastening member that fastens the cover fixing portion to the main body portion, and the tension adjustment mechanism is disposed on one side of the cover fixing portion and the fastening member in the first direction.

3. The tension adjustment mechanism includes a moving member that is attached to the cover so as to be movable in the first direction, abuts against the guide portion, and applies a biasing force to the guide portion; a biasing member that biases the moving member to the other side in the first direction; and a switching member connected to the moving member. In the non-biasing state, the movement of the moving member to the other side in the first direction is restricted by the switching member when the moving member is not in contact with the guide portion, and in the biasing state, the movement restriction state of the moving member by the switching member is released. The working machine according to claim 1.

4. The switching member is configured to be engageable with the cover. In the non-biasing state, the switching member engages with the cover to prevent the moving member from moving to the other side in the first direction, and in the biasing state, the engagement of the switching member with the cover is released to permit the moving member to move to the other side in the first direction. The working machine according to claim 3.

5. The switching member is connected to the moving member so as to be relatively rotatable about a second direction orthogonal to the first direction as an axial direction, and at an engagement position of the switching member with the cover in the first direction, when the switching member rotates relative to the moving member, the switching member switches to an engaged state in which the switching member engages with the cover or a disengaged state in which the engagement of the switching member with the cover is released. The working machine according to claim 4.

6. The guide portion extends in the first direction. In the non-urged state, the moving member is disposed spaced apart from the guide portion on one side in the first direction, and in the urged state, the moving member abuts against one side end portion of the guide portion in the first direction from one side in the first direction. The working machine according to claim 3.

7. The working machine according to claim 1, wherein the tension adjusting mechanism overlaps the rotating portion when viewed from the axial direction of the rotating portion.

8. A motor, a main body portion that supports the motor, a guide portion that is movably attached to the main body portion in a first direction, a rotating portion that is provided on one side in the first direction of the guide portion and rotates by a driving force of the motor, a sochain spanned between an outer peripheral portion of the rotating portion and an outer peripheral portion of the guide portion, a cover that is detachably attached to the main body portion, covers a part of the rotating portion and the sochain, and fixes the guide portion to the main body portion by being attached to the main body portion, and a tension adjusting mechanism that is provided on the cover and biases the guide portion to the other side in the first direction. The working machine, wherein the tension adjusting mechanism overlaps the rotating portion when viewed from the axial direction of the rotating portion.

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