Work machine

Abstract

In a side view of an electric cutter 10, the center of gravity G1 of the electric cutter 10 is at a position in the up / down direction of the electric cutter 10 that coincides with a blade 60 for cutting a workpiece W. In other words, in side view, the center of gravity G1 of the electric cutter 10 is within the range of the width dimension B of the blade 60 in the up / down direction. As a result, when the electric cutter 10 is standing, the center of gravity G1 of the electric cutter 10 is below the blade 60 in the vertical direction. This improves the work properties of the electric cutter 10.

Description

Work equipment

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

[0002] In the electric reciprocating tool (working machine) described in Patent Document 1 below, a backing plate is provided at the front end of the electric reciprocating tool, and a blade holder is provided behind the backing plate. A housing is provided behind the blade holder, and the housing includes a motor chamber extending in the front-rear direction and a handle extending in a direction intersecting the motor chamber. A workpiece is placed on the backing plate, and by operating a main switch on the handle, the movable blade moves forward to cut the workpiece.

[0003] Japanese Patent Application Laid-Open No. 2001-277039

[0004] However, the above-described power reciprocating tool leaves room for improvement in the following respects. For example, when cutting a workpiece, such as a ceiling material fixed to a ceiling, the ceiling material located vertically above the operator must be set on the backing plate of the power reciprocating tool. Specifically, the longitudinal direction of the power reciprocating tool is aligned with the vertical direction and the power reciprocating tool is suspended from the ceiling material. In this case, if the position of the power reciprocating tool is tilted relative to the vertical direction, the finish of the cut surface of the ceiling material may deteriorate. Therefore, in this case, the position of the power reciprocating tool must be corrected to align with the vertical direction during work, which may reduce workability. Furthermore, when cutting a workpiece, such as a ceiling material fixed to a ceiling, the ceiling material located vertically above the power reciprocating tool must be set on the backing plate. In this case, the handle position of the power reciprocating tool is offset from the position where the ceiling material is set, which causes a misalignment in the position of the ceiling material relative to the operator's hand, making it difficult to grasp the position of the backing plate relative to the target cutting position. Therefore, it is possible that the workability of setting the light-weight ceiling material on the support plate may be reduced. Also, if the handle position is offset from the position where the light-weight ceiling material is set, the handle may hit the wall when working on light-weight ceiling material located next to a wall, which may reduce the workability.

[0005] SUMMARY OF THE INVENTION In consideration of the above, an object of the present invention is to provide a work machine that can improve workability.

[0006] One or more embodiments of the present invention are a work machine comprising a housing extending in a first direction, and a cutting tool arranged on one side of the housing in the first direction so as to be able to move back and forth in the first direction, formed in a plate shape with a second direction perpendicular to the first direction as its width direction and a third direction perpendicular to the first and second directions as its plate thickness direction, which cuts plasterboard material by moving to one side in the first direction, and whose center of gravity is located at a position that overlaps with the cutting tool in the second direction when viewed from the third direction.

[0007] One or more embodiments of the present invention are directed to a work machine, wherein the housing has a grip portion, and at least a portion of the grip portion is positioned in a position that overlaps with the center of gravity in the first direction.

[0008] One or more embodiments of the present invention are directed to a work machine in which the gripping portion extends in the first direction.

[0009] One or more embodiments of the present invention are a work machine in which a support part for supporting the plasterboard material is provided on one side of the cutting tool in the first direction, and a V-shaped blade part is formed on one end of the cutting tool in the first direction that is convex toward one side of the first direction when viewed from the third direction, and in the second direction, the tip of the blade part is positioned in a position offset to one side of the second direction from the center of the support part in the second direction, and the center of gravity is positioned in a position offset to the other side of the second direction from the center of the support part in the second direction.

[0010] In one or more embodiments of the present invention, the housing contains a motor for reciprocating the cutting tool, and the motor is positioned offset to one side in the second direction from the center of the support part in the second direction.

[0011] One or more embodiments of the present invention are a work machine in which the housing is provided with a power supply unit for supplying power to the motor, and the power supply unit is positioned at a position offset to the other side of the second direction relative to the center of the second direction on the support part.

[0012] One or more embodiments of the present invention are a work machine in which, when viewed from the third direction, a portion of the gripping portion is located outside an imaginary circle centered on the center of the support portion in the second direction and passing through the center of gravity.

[0013] One or more embodiments of the present invention are directed to a work machine in which, when viewed from the third direction, a part of the gripping portion is positioned so as to overlap the support portion in the second direction.

[0014] According to one or more embodiments of the present invention, workability can be improved.

[0015] 1 is a side view of the electric cutter according to the first embodiment, as seen from the left side; FIG. 2 is a partially broken side view of the electric cutter shown in FIG. 1 , as seen from the left side, showing the interior of the electric cutter; FIG. 3 is a cross-sectional view (cross-sectional view along line 3-3 in FIG. 1 ) of an enlarged view of the intermediate portion of the grip shown in FIG. 1 in the front-rear direction, as seen from the rear; FIG. 4 is a flowchart for explaining the operation of the electric cutter according to the first embodiment; FIG. 5 is an explanatory view for explaining the tilt of an electric cutter of a comparative example, in an upright position, in which the center of gravity is shifted; FIG. 6 is a side view from the left side showing the interior and center of gravity of an electric cutter according to a second embodiment; FIG. 7 is a perspective view of the electric cutter shown in FIG. 6; FIG. 8A is a side view from the left side showing the interior and center of gravity of an electric cutter according to a third embodiment; and FIG. 8B is a schematic cross-sectional view (cross-sectional view along line 8B-8B in FIG. 8A ) of the connecting portion of the electric cutter shown in FIG. 8; FIG. 9 is a perspective view of the electric cutter shown in FIG. 10; 12 is a perspective view of the electric cutter shown in FIG. 13. (A) is a side view of the electric cutter according to the sixth embodiment, as seen from the left side, and (B) is a side view of the interior of the electric cutter of (A) as seen from the left side. (A) is a side view of the electric cutter according to the seventh embodiment, as seen from the left side, and (B) is a side view of the interior of the electric cutter of (A) as seen from the left side. (A) is a side view of the electric cutter according to the eighth embodiment, as seen from the left side, and (B) is a side view of the interior of the electric cutter of (A) as seen from the left side. (A) is a side view of the electric cutter according to the ninth embodiment, as seen from the left side, and (B) is a side view of the interior of the electric cutter of (A) as seen from the left side. (A) is a side view of the electric cutter according to the tenth embodiment, as seen from the left side, and (B) is a side view of the interior of the electric cutter of (A) as seen from the left side.

[0016] First Embodiment An electric cutting machine 10 as a work machine according to a first embodiment will be described below with reference to Figures 1 to 5. Note that the arrows UP, FR, and LH shown as appropriate in the drawings indicate the upper side, front side, and left side of the electric cutting machine 10, 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 electric cutting machine 10 unless otherwise specified. The front-rear direction corresponds to the first direction in the present invention, the up-down direction corresponds to the second direction in the present invention, and the left-right direction corresponds to the third direction in the present invention.

[0017] As shown in Figures 1 and 2, the electric cutter 10 is configured as an electric tool for cutting a workpiece W, such as a light-weight ceiling material used in a suspended ceiling of a building. The workpiece W is formed in a long, columnar shape and is formed into a roughly U-shape when viewed in the longitudinal direction. The light-weight ceiling material is made of metal, and naturally, the cross section (orthogonal to the longitudinal direction) also has a roughly U-shape. The electric cutter 10 includes a housing 20, a motor 40, a feed screw mechanism 50 (broadly understood as an element of a movement mechanism), a blade 60 as a cutting tool, a guide mechanism 70, and a controller 90. Each component of the electric cutter 10 will be described below.

[0018] (Regarding the Housing 20) The housing 20 forms the outer shell of the electric cutting machine 10 and extends in the front-to-rear direction as a whole. The housing 20 includes a handle housing portion 20A that forms the front portion of the housing 20 and a motor housing portion 20B that forms the rear portion of the housing 20. The handle housing portion 20A is formed in a generally rectangular tubular shape extending in the front-to-rear direction. A pair of protruding portions 20A1 are formed at the front end of the handle housing portion 20A, protruding to both sides in the up-down direction. A handle guard 20C serving as a guard portion is provided below the handle housing portion 20A. The handle guard 20C is formed in a generally rectangular tubular shape extending in the front-to-rear direction. The front end of the handle guard 20C is bent upward and connected to the lower protruding portion 20A1, and the rear end of the handle guard 20C is bent diagonally upward and rearward and connected to the rear end of the handle housing portion 20A. The portion of the handle housing portion 20A between the front and rear ends of the handle guard 20C forms a grip portion 20A2 that is gripped by the operator. That is, the grip portion 20A2 extends in the front-rear direction behind the protrusions 20A1. The left-right dimension of the front end of the handle housing portion 20A having the pair of protrusions 20A1 is set to be larger than the left-right dimension of the grip portion 20A2, and the front end of the handle housing portion 20A protrudes outward in the left-right direction beyond the grip portion 20A2 (see FIG. 3).

[0019] The motor housing 20B is formed in a generally flat shape with its thickness extending in the left-right direction. The thickness of the motor housing 20B is set to be greater than the thickness (left-right dimension) of the handle housing 20A. The upper end of the motor housing 20B protrudes above the handle housing 20A, and the lower end of the motor housing 20B is located above the handle guard 20C.

[0020] A trigger 30 is provided at the front end of the grip portion 20A2 as an operating portion for instructing the start of movement of the blade 60 (start of cutting), which will be described later. The trigger 30 protrudes downward from the grip portion 20A2 so as to be pulled upward. A trigger switch 32 is provided below the trigger 30 at the front end of the handle housing portion 20A. Pulling the trigger 30 switches the trigger switch 32 from off to on. Releasing the pulling of the trigger 30 switches the trigger switch 32 from on to off.

[0021] The trigger switch 32 is electrically connected to a controller 90 (described later), which is housed in the rear end of the motor housing portion 20B. When the trigger switch 32 is turned on, the trigger switch 32 outputs an on signal to the controller 90.

[0022] A battery mounting section 20D is provided at the lower end of the motor housing section 20B, behind the handle guard 20C. The battery mounting section 20D is provided with a battery terminal 22 serving as a power supply for supplying power to the motor 40, and the battery terminal 22 is electrically connected to a controller 90 (described later). A battery 24 is detachably mounted in the battery mounting section 20D, and the battery 24 has a connector (not shown) that connects to the battery terminal 22. This allows power to be supplied to the motor 40 (described later) via the controller 90. The lower end of the battery 24 is aligned with the lower end of the handle guard 20C in the up-down direction. In other words, the battery 24 is configured not to protrude below the handle guard 20C. The rear end of the motor housing section 20B protrudes rearward beyond the battery 24 and is curved in a generally arc-like shape that protrudes rearward in a side view.

[0023] A sub-trigger 34 (broadly understood as an erroneous operation suppression unit) for suppressing erroneous operation of the trigger 30 is provided at the upper end of the motor housing unit 20B. The sub-trigger 34 is configured to slide forward. A sub-trigger switch 36 is provided within the upper end of the motor housing unit 20B below the sub-trigger 34 and is electrically connected to a controller 90 (described later). When the sub-trigger 34 is slid, the sub-trigger switch 36 switches from OFF to ON and outputs an ON signal to the controller 90. When the sub-trigger 34 is released from the sliding operation, the sub-trigger 34 moves rearward and the sub-trigger switch 36 switches from ON to OFF. In addition, the electric cutter 10 is configured such that, when the sub-trigger switch 36 is turned ON and then the trigger switch 32 is turned ON at the start of cutting, forward rotation of the motor 40 (described later) is permitted. In other words, the sub-trigger 34 is configured as an operating unit for suppressing erroneous operation of the trigger 30 at the start of cutting.

[0024] An inner guide 38 is provided at the front end of the handle housing 20A, and is formed in a generally cylindrical shape with its axial direction extending in the front-to-rear direction. The rear portion of the inner guide 38 is supported by the handle housing 20A, and the front portion of the inner guide 38 protrudes forward from the handle housing 20A. A pair of upper and lower slits 38A are formed in the front portion of the inner guide 38 for arranging a blade 60, which will be described later. The slits 38A extend in the front-to-rear direction and penetrate in the up-down direction, with the front end of the slits 38A opening forward.

[0025] (Regarding the Motor 40) The motor 40 is configured as a brushless motor and is housed in the front portion of the motor housing portion 20B. The motor 40 has a drive shaft 40A whose axial direction is the front-to-rear direction. The rear end of the drive shaft 40A is rotatably supported by a motor bearing 42 held in the housing 20, and the front end portion of the drive shaft 40A is rotatably supported by a motor bearing 44 held in the housing 20. A pinion gear 40B is formed on the front end of the drive shaft 40A. The motor 40 is electrically connected to the controller 90 and is driven under the control of the controller 90.

[0026] (Regarding the feed screw mechanism 50) The feed screw mechanism 50 is composed of a transmission gear 51, a drive shaft 53 (broadly speaking, an element that can be understood as an output shaft), a lifter 55 (broadly speaking, an element that can be understood as a moving member), and a lifter detection switch 58 for detecting the initial position of the lifter 55 (broadly speaking, an element that can be understood as an initial position detection unit).

[0027] The transmission gear 51 is formed in a generally stepped cylindrical shape with its axial direction extending in the front-to-rear direction, and the diameter of the front portion of the transmission gear 51 is set to be larger than the diameter of the rear portion of the transmission gear 51. A gear recess 51A that is open to the front is formed in the center of the front surface of the transmission gear 51. The transmission gear 51 is disposed below the front end of the drive shaft 40A of the motor 40, and the rear portion of the transmission gear 51 is rotatably supported by a gear bearing 52 held in the housing 20. A gear portion 51B is formed on the outer periphery of the front portion of the transmission gear 51, and the gear portion 51B is engaged with the pinion gear 40B of the drive shaft 40A.

[0028] The drive shaft 53 is formed in a generally cylindrical shape with its axial direction extending in the front-to-rear direction. The drive shaft 53 is housed within the handle housing portion 20A and is disposed in front of and coaxial with the transmission gear 51. The rear end of the drive shaft 53 is fitted into a gear recess 51A of the transmission gear 51 so as to be rotatable together with the transmission gear 51, and the rear end portion of the drive shaft 53 is rotatably supported by a shaft bearing 54 held in the housing 20. As a result, when the motor 40 is driven, the drive shaft 53 rotates. A male thread 53A is formed on the outer periphery of the drive shaft 53, except for the rear end.

[0029] The lifter 55 is formed in a generally elongated shape extending in the front-to-rear direction as a whole. The lifter 55 includes a lifter main body 56 and a lifter connecting portion 57 that forms the rear end of the lifter 55. The lifter connecting portion 57 is formed in a generally stepped cylindrical shape with its axial direction extending in the front-to-rear direction. A female thread 57A is formed on the inner periphery of the rear portion of the lifter connecting portion 57. The front portion of the drive shaft 53 is inserted into the lifter connecting portion 57, and the male thread 53A of the drive shaft 53 and the female thread 57A of the lifter connecting portion 57 are threadedly engaged with each other. In other words, the drive shaft 53 and the lifter 55 are threadedly engaged with each other.

[0030] As a result, rotation of the drive shaft 53 causes the lifter 55 to move in the front-to-rear direction. Specifically, the lifter 55 moves back and forth between an initial position (the position indicated by the solid line in FIG. 2) and a processing position (the position indicated by the two-dot chain line in FIG. 2). The outer periphery of the rear end of the lifter connecting portion 57 is configured as a detection target portion 57B.

[0031] The lifter body 56 is formed in a generally cylindrical shape with a bottom that is open to the rear. The rear end of the lifter body 56 is fitted into the front part of the lifter connecting part 57, and the lifter connecting part 57 and the lifter body 56 are connected so as not to move relative to each other. When the lifter 55 is in the initial position, the front part of the drive shaft 53 is inserted into the lifter body 56 so as to be able to move relatively. The front end of the lifter body 56 is supported by an inner guide 38 provided at the front end of the handle housing part 20A so as to be able to move relatively in the front-rear direction.

[0032] A lifter flange 56A is formed on the outer periphery of the rear end portion of the lifter body 56, and the lifter flange 56A is formed in a disk shape that protrudes radially outward from the lifter body 56. Although not shown in the drawings, at the processing position of the lifter 55, the lifter flange 56A is disposed close to the rear side of the inner guide 38.

[0033] The lifter detection switch 58 is configured as a lever-type microswitch and is housed in the rear end of the handle guard 20C. A spherical ball 59 is provided on the upper side of the lifter detection switch 58, and the ball 59 is disposed in a ball hole 20E formed in the lower end of the outer periphery of the handle housing 20A. The ball hole 20E penetrates vertically, and the diameter of the ball hole 20E increases downward. When the lifter detection switch 58 is in the OFF state, the outer periphery of the ball 59 abuts against the lever portion of the lifter detection switch 58 and the inner periphery of the ball hole 20E. In this state, a portion of the outer periphery of the ball 59 protrudes radially inward relative to the inner periphery of the handle housing 20A so as to be disposed within the handle housing 20A.

[0034] When the lifter 55 is placed in the initial position, the detected portion 57B of the lifter 55 presses the ball 59 radially outward (downward), displacing the ball 59 toward the lifter detection switch 58 (downward). In other words, when the lifter 55 reaches the initial position while moving in the return direction from the processing position to the initial position, the ball 59 presses the lever portion of the lifter detection switch 58, switching the lifter detection switch 58 from off to on. The lifter detection switch 58 is electrically connected to the controller 90 and outputs a detection signal to the controller 90.

[0035] (Regarding the Blade 60) The blade 60 is formed in the shape of a plate extending vertically and longitudinally, with the left-right direction being the plate thickness direction. The rear end of the blade 60 is fixed to the front end of the lifter 55 by a screw 61. This allows the blade 60 to move integrally with the lifter 55 between the initial position and the processing position. The rear end of the blade 60 is inserted into the slit 38A of the inner guide 38. The front end of the blade 60 is formed with a cutting edge 60A for cutting the workpiece W. The cutting edge 60A is configured as a single-edged edge and is formed in a generally V-shape that protrudes forward when viewed from the left-right direction.

[0036] In the initial position of the blade 60, the blade 60 is disposed adjacent to the front side of the housing 20 and is disposed behind the workpiece W, and as the blade 60 moves forward from the initial position, cutting is performed on the workpiece W. Furthermore, the cutting position of the blade 60 is set so that cutting of the workpiece W is completed.

[0037] (Regarding the guide mechanism 70) The guide mechanism 70 is configured to include a blade holder 72, a connecting member 76, and a head portion 80 as a processing portion. The head portion 80 functions as a member (support portion) that supports the workpiece W. Note that the workpiece W, such as a ceiling material, may be fixed to a specific location (such as a wall or ceiling), but in the present invention, the state in which the head portion 80 engages with the workpiece W in such a fixed state is also considered to be a state in which the workpiece W is supported by the head portion 80.

[0038] The blade holder 72 has a pair of left and right holder plates 74. The holder plates 74 are made of metal plate material and are formed into a generally rectangular plate shape with the left-right direction as the plate thickness direction. A fixing portion 74A is formed in the middle of the holder plate 74 in the up-down direction, and the fixing portion 74A is formed into a generally arc shape that convex outward in the left-right direction when viewed from the front. The fixing portion 74A is disposed radially outward of the inner guide 38 and is fastened to the inner guide 38 by a pair of front and rear bolts BL1. This fixes the holder plate 74 to the inner guide 38.

[0039] The pair of holder plates 74 are disposed opposite each other with a predetermined gap left and right. The distance between the lower portions of the pair of holder plates 74 is set to be slightly longer than the thickness of the blade 60, and the blade 60 is disposed between the pair of holder plates 74. As a result, when the drive shaft 53 rotates, the lower portion of the blade holder 72 restricts the rotation of the lifter 55 and the blade 60 together with the drive shaft 53, and the blade holder 72 guides the reciprocating movement of the blade 60 in the front-to-rear direction.

[0040] The connecting member 76 is made of a metal plate and is formed in a generally elongated plate shape with its thickness in the left-right direction and its length in the front-rear direction. The connecting member 76 is disposed between the upper ends of the pair of holder plates 74 and is fastened to the holder plates 74 by bolts BL2.

[0041] The head unit 80 has a pair of left and right head plates 82. The head plates 82 are made of metal plate material and are formed into plate shapes with their thickness direction in the left-right direction. The pair of head plates 82 are disposed in front of the holder plate 74 and on the outside in the left-right direction of the connecting member 76, and the upper ends of the head plates 82 are fastened and fixed to the front end of the connecting member 76 by bolts BL2. As a result, the pair of head plates 82 are disposed opposite each other with a predetermined gap left and right.

[0042] A support portion 80A for supporting the workpiece W is formed at the rear end of the head portion 80. The support portion 80A is generally comb-shaped, with its width extending vertically and open toward the rear. Specifically, the support portion 80A is provided with a plurality of (four in this embodiment) notches 80A1 that are open toward the rear and are formed through the support portion 80A. The notches 80A1 are arranged side by side at predetermined intervals in the width direction of the support portion 80A. When cutting the workpiece W, both ends of the workpiece W, as viewed from the longitudinal direction of the workpiece W, are inserted into the notches 80A1, and the workpiece W is set (supported) on the head portion 80. In this manner, the workpiece W is supported by the head portion 80 with a portion of the workpiece W positioned in the notch 80A1. In this embodiment, the provision of four notches 80A1 allows for the cutting of workpieces W with widths corresponding to the combination of recesses.

[0043] Furthermore, in a side view, the entire gripping portion 20A2 of the housing 20 is positioned so as to overlap the support portion 80A of the head portion 80 in the vertical direction (the same position in the vertical direction). That is, when viewed from the left and right, the gripping portion 20A2 is positioned within the range of the width dimension A (see FIG. 1) of the comb-shaped support portion 80A and extends in the front-rear direction. In other words, when viewed from the front-rear direction, the gripping portion 20A2 and the support portion 80A overlap, and the gripping portion 20A2 is positioned directly behind the support portion 80A (guide mechanism 70) (see FIG. 3). When cutting the workpiece W, the blade 60, which moves forward, is inserted between the pair of head plates 82 and cuts the workpiece W supported by the support portion 80A. The width dimension A is the range from one end to the other end in a predetermined direction (vertical direction) of the multiple cutouts 80A1 aligned in the predetermined direction (vertical direction). Furthermore, the width dimension A of the support portion 80A is set slightly smaller than the width dimension B (vertical dimension) of the blade 60, and when viewed from the left and right, the support portion 80A is disposed within the range of the width dimension B of the blade 60. Furthermore, the tip portion 60B of the cutting portion 60A of the blade 60 is disposed at a position offset upward from the center portion 80A2 of the support portion 80A in the vertical direction in side view (see FIG. 1).

[0044] Furthermore, in a side view, a portion of the trigger 30 of the housing 20 is disposed at a position that overlaps with the support portion 80A in the up-down direction (see FIG. 3). That is, when viewed from the left-right direction, a portion of the trigger 30 is disposed within the range of the width dimension A of the support portion 80A and extends in the front-rear direction. In other words, when viewed from the front-rear direction, a portion of the trigger 30 overlaps with the support portion 80A (see FIG. 3).

[0045] (Regarding the Controller 90) As shown in FIG. 2 , the controller 90 is accommodated in the rear end of the motor housing portion 20B of the housing 20 and is held by the housing 20. The trigger switch 32, the sub-trigger switch 36, the motor 40, and the lifter detection switch 58 are electrically connected to the controller 90. The controller 90 detects the initial position of the lifter 55 based on a detection signal from the lifter detection switch 58. The controller 90 also controls the drive of the motor 40 based on output signals from the trigger switch 32, the sub-trigger switch 36, and the lifter detection switch 58. When the controller 90 drives the motor 40 in the forward direction, the lifter 55 (blade 60) moves forward, and when the controller 90 drives the motor 40 in the reverse direction, the lifter 55 (blade 60) moves rearward.

[0046] Furthermore, when the operation of the trigger 30 is released and the trigger switch 32 is switched from ON to OFF while the motor 40 is rotating forward, the controller 90 drives the motor 40 in the reverse direction. Furthermore, the controller 90 has a motor drive detector 90A that detects the number of rotations of the drive shaft 40A of the motor 40. The controller 90 detects the number of rotations of the motor 40 from its initial position based on a detection signal from the motor drive detector 90A. This allows the controller 90 to detect the machining position of the lifter 55 (blade 60) based on the number of rotations of the motor 40, starting from the initial position of the lifter 55. Furthermore, when the controller 90 detects the machining position of the lifter 55 (blade 60), it stops driving the motor 40.

[0047] (Regarding the Position of the Center of Gravity of the Electric Cutting Machine 10) Next, the position of the center of gravity G1 of the electric cutting machine 10 will be described. As shown in FIG. 1 , the center of gravity G1 of the electric cutting machine 10 is located within the width dimension B of the blade 60 in a side view. That is, the center of gravity G1 is located at a position overlapping the blade 60 in the up-down direction. Specifically, in a side view, the center of gravity G1 is located rearward of the trigger 30 and overlapping with the lower end portion of the grip portion 20A2 at approximately the center in the front-to-rear direction. That is, in the up-down direction, the center of gravity G1 is offset downward from the center portion 80A2 of the support portion 80A. Furthermore, as described above, because the center of gravity G1 overlaps with the lower end portion of the grip portion 20A2 at approximately the center in the front-to-rear direction in a side view, the rear portion of the grip portion 20A2 is located outside the imaginary circle CR that is centered on the center portion 80A2 of the support portion 80A and passes through the center of gravity G1. 3, the center of gravity G1 of the electric cutter 10 is located in the center of the electric cutter 10 in the left-right direction. In other words, when viewed from the front-rear direction, the center of gravity G1 overlaps with the blade 60 and the support portion 80A.

[0048] (Operations and Effects) Next, the operations of the electric cutting machine 10 will be described, and the operations and effects of the electric cutting machine 10 according to this embodiment will be described.

[0049] 4 is a flowchart of the electric cutter 10. As shown in this figure, in the operation of the electric cutter 10, in step 1 (S1), the controller 90 detects whether the sub-trigger switch 36 is on based on the output signal from the sub-trigger switch 36. That is, the controller 90 determines whether the sub-trigger switch 36 has been operated. If the sub-trigger switch 36 is not on in step 1 (No in step 1), the process returns to step 1. If the sub-trigger switch 36 is on in step 1 (Yes in step 1), the process proceeds to step 2 (S2).

[0050] In step 2, the controller 90 detects whether the trigger switch 32 is on based on the output signal from the trigger switch 32. That is, the controller 90 determines whether the trigger 30 has been operated while the sub-trigger switch 36 is on. If the trigger switch 32 is not on in step 2 (No in step 2), the process returns to step 1. If the trigger switch 32 is on in step 2 (Yes in step 2), the process proceeds to step 3 (S3). Note that even if the sub-trigger switch 36 switches from on to off in step 3 and onwards, the operation of the electric cutter 10 continues.

[0051] In step 3, the controller 90 detects whether the lifter detection switch 58 is turned on based on the output signal from the lifter detection switch 58. That is, the controller 90 determines whether the lifter 55 is placed in the initial position. In step 3, if the lifter detection switch 58 is turned on (Yes in step 3), the process proceeds to step 4 (S4).

[0052] In step 4, the controller 90 drives the motor 40 in the forward direction. That is, when the controller 90 detects the initial position of the lifter 55, the controller 90 drives the motor 40 in the forward direction. As a result, the lifter 55 and the blade 60 move forward (toward the forward path), and the blade 60 approaches the workpiece W. After processing step 4, the process proceeds to step 5 (S5).

[0053] In step 5, the controller 90 detects whether the trigger switch 32 continues to be in the on state based on the output signal from the trigger switch 32. That is, the controller 90 determines whether the trigger 30 is being operated. In step 5, if the trigger switch 32 continues to be in the on state (Yes in step 5), the process proceeds to step 6 (S6).

[0054] In step 6, the controller 90 detects whether the lifter detection switch 58 has been switched from on to off based on the output signal from the lifter detection switch 58. If the lifter detection switch 58 has been switched off in step 6 (Yes in step 6), the process proceeds to step 7 (S7). That is, in this embodiment, the position of the lifter 55 at which the lifter detection switch 58 has been switched from on to off is set as the starting point of the initial position of the lifter 55 moving forward (hereinafter, this position of the lifter 55 is referred to as the initial starting point position), and in step 6, the controller 90 detects the initial starting point position of the lifter 55. On the other hand, if the lifter detection switch 58 has not been switched off in step 6 (No in step 6), the process returns to step 5. That is, if the lifter 55 moving forward from the initial position has not reached the initial starting point position, the process returns to step 5.

[0055] In step 7, the controller 90 starts measuring the number of rotations of the motor 40. Specifically, the controller 90 starts measuring (counting) the number of rotations of the motor 40 based on a signal from the motor drive detection unit 90A. After processing in step 7, the process proceeds to step 8 (S8).

[0056] In step 8, the controller 90 detects whether the trigger switch 32 continues to be in the on state based on the output signal from the trigger switch 32. That is, the controller 90 determines whether the operation of the trigger 30 continues. In step 8, if the trigger switch 32 continues to be in the on state (Yes in step 8), the process proceeds to step 9 (S9).

[0057] In step 9, the controller 90 determines whether the rotation speed of the motor 40 has reached or exceeded a predetermined rotation speed. That is, the controller 90 determines whether the lifter 55 has reached the processing position. In step 9, if the rotation speed of the motor 40 is not equal to or greater than the predetermined rotation speed (No in step 9), the process returns to step 8. In step 9, if the rotation speed of the motor 40 is equal to or greater than the predetermined rotation speed (Yes in step 9), the process proceeds to step 10 (S10).

[0058] In step 10, the forward rotation of the motor 40 is stopped by the controller 90. After the processing of step 10, the process proceeds to step 11 (S11).

[0059] In step 11, the motor 40 is placed in a standby state. That is, after the forward rotation of the motor 40 is stopped, the controller 90 does not control the drive of the motor 40, and the motor 40 is placed in a standby state. After the processing of step 11, the process proceeds to step 12 (S12). Specifically, the process proceeds to step 12 after a predetermined time has elapsed after the forward rotation of the motor 40 is stopped.

[0060] In step 12, it is detected whether or not the trigger switch 32 is on based on the output signal from the trigger switch 32. If the trigger switch 32 is not on in step 12 (No in step 12), the process returns to step 12. If the trigger switch 32 is on in step 12 (Yes in step 12), the process proceeds to step 13 (S13).

[0061] In step 13, the controller 90 drives the motor 40 in the reverse direction. As a result, the lifter 55 and the blade 60 move rearward (toward the return path) and separate from the workpiece W. That is, the lifter 55 and the blade 60 are reversed at the processing position, and the return path movement of the lifter 55 and the blade 60 begins. After the processing of step 13, the process proceeds to step 14 (S14).

[0062] In step 14, the controller 90 detects whether the lifter detection switch 58 is turned on based on the output signal from the lifter detection switch 58. That is, the controller 90 determines whether the lifter 55 has reached the initial position. If the lifter detection switch 58 is not turned on in step 14 (No in step 14), the process returns to step 14. On the other hand, if the lifter detection switch 58 is turned on in step 14 (Yes in step 14), the process proceeds to step 15 (S15).

[0063] In step 15, the reverse rotation of the motor 40 by the controller 90 is stopped, thereby stopping the lifter 55 at the initial position. After the processing of step 15, the process proceeds to step 16 (S1).

[0064] In step 16, the controller 90 detects whether the trigger switch 32 has been switched from on to off based on the output signal from the trigger switch 32. That is, the controller 90 detects whether the operation of the trigger 30 has been released. If the trigger switch 32 is not off in step 16 (No in step 16), the process returns to step 16. On the other hand, if the trigger switch 32 is off in step 16 (Yes in step 16), the operation of the trigger 30 has been released, and the operation of the electric cutter 10 is terminated.

[0065] In step 3, if the lifter detection switch 58 is not on (No in step 3), the process proceeds to step 13. That is, in this case, the lifter 55 has not returned to the initial position when the electric cutter 10 starts operating, so the process proceeds to step 13, and the lifter 55 is returned to the initial position.

[0066] Furthermore, in steps 5 and 8, if the trigger switch 32 does not continue to be in the on state (if the answer is No in steps 5 and 8), the process proceeds to step 17. In step 17, the controller 90 stops the forward rotation of the motor 40, and after the forward rotation of the motor 40 has stopped, the process proceeds to step 18. In step 18, similar to step 11, the motor 40 is put into a standby state, and after the motor 40 has entered the standby state, the process proceeds to step 13. That is, in this case, the operator's operation on the trigger 30 is released while the lifter 55 is moving forward. Therefore, the controller 90 stops the forward rotation of the motor 40, and after a predetermined time has elapsed, drives the motor 40 in the reverse direction to return the lifter 55 to the initial position.

[0067] When cutting a workpiece W, such as a ceiling-mounted material fixed to a ceiling or the like, an operator positioned vertically below the workpiece W places the electric cutter 10 in an upright position (a position in which the front-to-rear direction of the electric cutter 10 is aligned with the vertical direction so that the head 80 is at the vertical upper end of the electric cutter 10) and positions the electric cutter 10 vertically below the workpiece W. The workpiece W is then inserted between the blade holder 72 and the head 80 and positioned vertically below the head 80. In this position, the workpiece W is inserted into the support portion 80A of the head 80 and set on the head 80. That is, the workpiece W is engaged with the support portion 80A of the head 80, and the electric cutter 10 is suspended from the workpiece W.

[0068] Here, in a side view of the electric cutter 10, the center of gravity G1 of the electric cutter 10 is located at a position overlapping with the blade 60 in the vertical direction of the electric cutter 10. In other words, the center of gravity G1 of the electric cutter 10 is located within the range of the width dimension B of the blade 60 in the vertical direction in a side view. Therefore, when the electric cutter 10 is in an upright position, the center of gravity G1 of the electric cutter 10 is located vertically below the blade 60 for cutting the workpiece W. This improves the operability of the electric cutter 10.

[0069] That is, if the center of gravity G1 of the electric cutter 10 is located outside the range of the width dimension B of the blade 60 in the vertical direction (hereinafter, this electric cutter will be referred to as the comparative electric cutter 10), when the electric cutter 10 is brought into an upright position, the center of gravity G1 will be located vertically below the workpiece W, and the electric cutter 10 of the comparative example will tend to tilt relative to the vertical direction. For example, as shown by the two-dot chain line in FIG. 5 , if the center of gravity G1 is located at the handle guard 20C, the electric cutter 10 of the comparative example will tilt so that the handle guard 20C is located vertically below the workpiece W. Therefore, the operator must apply a horizontal force F (see FIG. 5 ) to correct the position of the electric cutter 10 of the comparative example to the upright position shown by the solid line. Therefore, the workability of the electric cutter 10 of the comparative example may be reduced.

[0070] In contrast, in the electric cutter 10 of this embodiment, as described above, the center of gravity G1 is located within the range of the width dimension B of the blade 60 in the vertical direction. Therefore, when cutting in an upright position, the electric cutter 10 naturally assumes an upright position along the vertical direction. This makes it possible to suppress tilt of the blade 60 relative to the workpiece W. As a result, there is no need to correct the position as in the electric cutter 10 of the comparative example. Therefore, the electric cutter 10 of this embodiment can improve workability.

[0071] Furthermore, the grip portion 20A2 of the housing 20 is positioned so as to overlap the center of gravity G1 in the front-rear direction. In this embodiment, in a side view, the center of gravity G1 overlaps the lower end portion of the grip portion 20A2 at approximately the center of the front-rear direction. That is, in this embodiment, the center of gravity G1 overlaps the grip portion 20A2 in the front-rear and up-down directions. Therefore, the grip portion 20A2, where the center of gravity G1 is located, can be gripped to perform cutting. Furthermore, when an operator grips the grip portion 20A2 to place the electric cutter 10 in an upright position, the burden on the operator of maintaining the upright position of the electric cutter 10 can be reduced. As a result, the workpiece W can be easily inserted between the blade holder 72 and the head portion 80. This further improves the operability of the electric cutter 10.

[0072] The grip 20A2 is positioned so as to overlap the center of gravity G1 in the front-rear direction and extends in the front-rear direction. This allows the electric cutter 10 to be well balanced when the operator holds the grip 20A2 of the electric cutter 10 in a horizontal position (a position in which the front-rear direction of the electric cutter 10 is aligned with the horizontal direction), for example. This improves the portability of the electric cutter 10 in the horizontal position.

[0073] Furthermore, the tip 60B of the cutting portion 60A of the blade 60 is positioned at a position offset upward from the center 80A2 of the support portion 80A in the width direction, and the center of gravity G1 is offset downward from the center 80A2 of the support portion 80A in the width direction. This makes it easier to ensure a sufficient distance from the tip 60B or the screw 61 (the connection portion between the blade 60 and the lifter 55) that receives the reaction force to the center of gravity G1. By positioning the center of gravity away from the position where the reaction force is generated, it is possible to prevent the electric cutter 10 from rotating when the reaction force is generated.

[0074] Furthermore, the rear of the gripping portion 20A2 is located outside an imaginary circle CR that is centered on the widthwise center 80A2 of the support portion 80A and passes through the center of gravity G1. This further improves the operability of the electric cutter 10. For example, when setting a workpiece W, such as a light-weight ceiling material, on the electric cutter 10 in an upright position, the workpiece W is set so as to be hooked onto the support portion 80A. At this time, the operator may generate a moment centered on the support portion 80A due to a force F acting on the gripping portion 20A2, causing the workpiece W to be hooked. Therefore, by gripping the gripping portion 20A2 at a distance from the center of gravity G1 relative to the support portion 80A, the operator can generate the moment with a relatively small force F and set the workpiece W so as to be hooked onto the support portion 80A. This further improves the operability of the electric cutter 10.

[0075] The motor 40 is accommodated in the motor housing portion 20B of the housing 20, and is positioned offset upward from the widthwise center 80A2 of the support portion 80A of the head portion 80. Specifically, the housing 20 extends in the front-to-rear direction, with the grip portion 20A2 constituting the front portion of the housing 20 and the motor housing portion 20B constituting the rear portion of the housing 20. This allows the rear end of the feed screw mechanism 50, which reciprocates the blade 60 using the driving force of the motor 40, and the front end of the motor 40 to be accommodated in the housing 20 so as to overlap in the front-to-rear direction. This contributes to reducing the size of the electric cutting machine 10 in the front-to-rear direction.

[0076] The motor housing 20B is provided with a battery mounting section 20D for mounting the battery 24, and the battery mounting section 20D is provided below the motor 40. The battery mounting section 20D is further provided with a battery terminal 22 for supplying power to the motor 40. This allows the battery 24 for supplying power to the motor 40 to be mounted in the housing 20 while preventing the electric cutter 10 from becoming too large in the front-to-rear direction.

[0077] Furthermore, in a side view, the entire gripping portion 20A2 is positioned so as to overlap the support portion 80A in the vertical direction. That is, the gripping portion 20A2 is positioned behind the head portion 80, and the gripping portion 20A2 and the support portion 80A overlap in the front-to-back direction. Therefore, when the electric cutter 10 is in an upright position, the gripping portion 20A2 is positioned directly below the support portion 80A in the vertical direction. This makes it easy to grasp the position of the support portion 80A (head portion 80) when setting a workpiece W, such as a light-weight ceiling material fixed to a ceiling, on the electric cutter 10. As a result, an operator holding the gripping portion 20A2 can easily move the head portion 80 toward the workpiece W and set the workpiece W on the support portion 80A of the head portion 80. This effectively improves the operability of the electric cutter 10. The grip portion 20A2 is provided with a trigger 30, and a portion of the trigger 30 overlaps with the support portion 80A when viewed from the front-to-rear direction. This allows the operator to operate the trigger 30 with the hand gripping the grip portion 20A2 while keeping their hand positioned directly behind the support portion 80A. This further improves the operability of the electric cutter 10.

[0078] The housing 20 also has a handle guard 20C extending in the front-rear direction. The handle guard 20C is located below the grip portion 20A2 and in front of the battery mounting portion 20D. That is, the handle guard 20C is located in a position overlapping the center of gravity G1 in the front-rear direction. This allows the electric cutter 10 to be placed in a stable state when the handle guard 20C is placed on the ground or the like with the electric cutter 10 in a horizontal position. As a result, the electric cutter 10 can be stored in a stable state, for example. Furthermore, cutting operations can be easily performed with the electric cutter 10 placed horizontally.

[0079] Second Embodiment Next, an electric cutter 200 as a work machine according to a second embodiment will be described with reference to Figures 6 and 7. The electric cutter 200 according to the second embodiment has the same configuration as the electric cutter 10 according to the first embodiment, except for the following points. In Figures 6 and 7, the same reference numerals are used to designate components that are configured in the same way as the electric cutter 10 according to the first embodiment.

[0080] That is, in the second embodiment, the handle guard 20C is omitted from the housing 20. The housing 20 has a longer longitudinal dimension than that of the first embodiment. The housing 20 includes a lifter housing portion 20F that forms the front end of the housing 20, a motor housing portion 20B that forms the middle portion of the housing 20 in the longitudinal direction, and a rear housing portion 20G that forms the rear portion of the housing 20. The lifter housing portion 20F is formed in a generally cylindrical shape extending in the longitudinal direction, and accommodates a feed screw mechanism 50. The motor housing portion 20B accommodates a motor 40, which is disposed at a position offset downward from the drive shaft 53 of the feed screw mechanism 50. The rear housing portion 20G accommodates a controller 90, and a battery attachment portion 20D is provided at the rear end of the rear housing portion 20G.

[0081] The grip portion 20A2 is disposed above the lifter housing portion 20F and extends in the front-to-rear direction. Specifically, the grip portion 20A2 extends in a direction that is slightly inclined upward as it approaches the front in a side view. The front end of the grip portion 20A2 is bent downward and connected to the front end of the lifter housing portion 20F, and the rear end of the grip portion 20A2 is bent downward and connected to the motor housing portion 20B. A trigger 30 that protrudes downward is provided at the front end of the grip portion 20A2. In the second embodiment, the handle guard 20C is omitted from the housing 20, but the area around the trigger 30 is protected by being surrounded by the lifter housing portion 20F and the grip portion 20A2.

[0082] Also in the second embodiment, the center of gravity G2 of the electric cutter 200 is located at a position overlapping with the blade 60 and the support portion 80A in the vertical direction of the electric cutter 200 in a side view. Specifically, the center of gravity G2 overlaps with the lifter housing portion 20F in a side view, and is located within the range of the width dimension B of the blade 60 and the range of the width dimension A of the support portion 80A in the vertical direction. Therefore, when the electric cutter 200 is in an upright position, the center of gravity G2 of the electric cutter 200 is located vertically below the blade 60 for cutting the workpiece W. This improves the operability of the electric cutter 200, as in the first embodiment.

[0083] In the second embodiment, the grip portion 20A2 of the housing 20 is also positioned so as to overlap the center of gravity G2 in the front-rear direction. This allows the operator to grip the grip portion 20A2, which is positioned so as to approximately coincide with the center of gravity G2 in the longitudinal direction of the electric cutter 200, and perform cutting. This further improves the operability of the electric cutter 200.

[0084] In the second embodiment, the grip 20A2 is also positioned so as to overlap the center of gravity in the front-rear direction and extends in the front-rear direction. This allows the electric cutter 200 to maintain good balance when held by an operator at the grip 20A2 in a horizontal position, improving portability of the electric cutter 200 in the horizontal position.

[0085] (Third embodiment) Next, an electric cutter 300 as a work machine according to a third embodiment will be described with reference to Figures 8 and 9. Note that Figure 8(A) shows a cross-sectional view similar to Figures 2 and 6, and Figure 8(B) is a schematic cross-sectional view taken along line 8B-8B in Figure 8(A). The electric cutter 300 according to the third embodiment is configured similarly to the electric cutter 10 according to the first embodiment, except for the following points. Note that in Figures 8 and 9, the same reference numerals are used to designate components that are configured similarly to the electric cutter 10 according to the first embodiment.

[0086] That is, in the third embodiment, similar to the second embodiment, the handle guard 20C is omitted from the housing 20. The housing 20 has a lifter housing portion 20F similar to the second embodiment and a motor housing portion 20B constituting the rear end of the housing 20. The lifter housing portion 20F constitutes the front portion of the housing 20 and accommodates a feed screw mechanism 50. The motor housing portion 20B accommodates a motor 40, which is disposed at a position offset upward relative to the drive shaft 53 of the feed screw mechanism 50. A battery mounting portion 20D is provided at the lower end of the motor housing portion 20B, and the battery 24 mounted in the battery mounting portion 20D is disposed below the motor housing portion 20B.

[0087] The grip portion 20A2 is disposed radially outward of the lifter housing portion 20F and extends in a direction perpendicular to the front-to-rear direction (in the example shown in FIG. 9 , the grip portion 20A2 is disposed below the lifter housing portion 20F and extends in the left-to-right direction). The grip portion 20A2 is connected to the lifter housing portion 20F by a connecting portion 302 and is configured to be rotatable in the circumferential direction of the lifter housing portion 20F. Specifically, the connecting portion 302 is provided radially outward of the lifter housing portion 20F, and both longitudinal ends of the grip portion 20A2 are bent toward the lifter housing portion 20F and connected to the connecting portion 302. As a result, the grip portion 20A2 extends radially outward of the lifter housing portion 20F in a direction perpendicular to the front-to-rear direction and is connected to the lifter housing portion 20F so as to be rotatable in the circumferential direction. A trigger 30 is provided at one longitudinal end of the grip portion 20A2, and the trigger 30 protrudes upward from the grip portion 20A2. As shown in FIG. 8B , the lifter housing portion 20F is provided with two protrusions 20H and two thinned portions 20J at rotational positions 180 degrees apart. The connecting portion 302 also has recesses 302H on its inner surface at 90-degree intervals. The engagement between the protrusions 20H and the recesses 302H fixes the rotational position of the grip portion 20A2. Because the protrusions 20H have a curved surface and the portions supporting the protrusions 20H are elastically deformable by the thinned portions 20J, applying a torque equal to or greater than a predetermined value to the grip portion 20A2 causes the protrusions 20H to retract radially inward and disengage from the recesses 302H. When the grip portion 20A2 is rotated in this state, the convex portion 20H fits into the concave portion 302H at a position 90 degrees different from the convex portion 20H, fixing the rotational position of the grip portion 20A2. The grip portion 20A2 is configured to be rotatable within a predetermined angular range (270 degrees) relative to the lifter housing portion 20F by a locking structure (not shown). In other words, the grip portion 20A2 can select one of four rotational positions at 90-degree intervals. The torque applied to the grip portion 20A2 required to change the rotational position can be adjusted by adjusting the amount of thinning of the thinned portion 20J. In this way, in the second embodiment, the position of the grip portion 20A2 is configured to be changeable, thereby improving operability.

[0088] In the third embodiment, the center of gravity G3 of the electric cutter 300 is also located at a position overlapping the blade 60 and the support portion 80A in the vertical direction of the electric cutter 200 in a side view. Specifically, in a side view, the center of gravity G3 overlaps the lifter housing portion 20F and is located within the range of the width dimension B of the blade 60 and the range of the width dimension A of the support portion 80A in the vertical direction. Therefore, when the electric cutter 300 is in an upright position, the center of gravity G3 of the electric cutter 300 is located vertically below the blade 60 for cutting the workpiece W. This improves the operability of the electric cutter 300, as in the first embodiment. Note that this center of gravity position relationship is configured to remain unchanged even when the rotational position of the grip portion 20A2 is changed.

[0089] Fourth Embodiment Next, an electric cutter 400 as a work machine according to a fourth embodiment will be described with reference to Figures 10 and 11. The electric cutter 400 according to the fourth embodiment has the same configuration as the electric cutter 10 according to the first embodiment, except for the following points. In Figures 10 and 11, the same reference numerals are used to designate components that are configured in the same way as the electric cutter 10 according to the first embodiment.

[0090] That is, in the fourth embodiment, similar to the second embodiment, the handle guard 20C is omitted from the housing 20. The housing 20 has a lifter housing portion 20F similar to the second embodiment and a motor housing portion 20B constituting the rear end of the housing 20. The lifter housing portion 20F constitutes the front portion of the housing 20 and accommodates a feed screw mechanism 50. The motor housing portion 20B accommodates a motor 40, which is disposed in a position offset downward with respect to the drive shaft 53 of the feed screw mechanism 50, similar to the second embodiment. A battery mounting portion 20D is provided at the upper end of the motor housing portion 20B, and the battery 24 mounted in the battery mounting portion 20D is disposed above the motor housing portion 20B.

[0091] The grip portion 20A2 extends in the vertical direction and downward from the front end portion of the lifter housing portion 20F. That is, the grip portion 20A2 extends from the front end portion of the lifter housing portion 20F radially outward from the lifter housing portion 20F. The battery 24 is not disposed behind the grip portion 20A2, and the grip portion 20A2 extends in the opposite direction to the direction in which the battery 24 protrudes relative to the housing 20. A trigger 30 protruding forward is provided at the upper end of the grip portion 20A2.

[0092] Also in the fourth embodiment, the center of gravity G4 of the electric cutter 400 is located at a position overlapping with the blade 60 and the support portion 80A in the vertical direction of the electric cutter 400 in a side view. Specifically, the center of gravity G4 overlaps with the lifter housing portion 20F in a side view, and is located within the range of the width dimension B of the blade 60 and the range of the width dimension A of the support portion 80A in the vertical direction. Therefore, when the electric cutter 400 is in an upright position, the center of gravity G4 of the electric cutter 400 is located vertically below the blade 60 for cutting the workpiece W. This improves the operability of the electric cutter 400, as in the first embodiment.

[0093] In the fourth embodiment, the grip portion 20A2 of the housing 20 is also positioned so as to overlap the center of gravity G4 in the front-rear direction. Therefore, cutting can be performed by gripping the grip portion 20A2, which is positioned so as to approximately coincide with the center of gravity G4 in the longitudinal direction of the electric cutter 400. This further improves the operability of the electric cutter 400.

[0094] Fifth Embodiment Next, an electric cutter 500 as a work machine according to a fifth embodiment will be described with reference to Figures 12 and 13. The electric cutter 500 according to the fifth embodiment has the same configuration as the electric cutter 10 according to the first embodiment, except for the following points. In Figures 12 and 13, the same reference numerals are used to designate components that are configured in the same way as the electric cutter 10 according to the first embodiment.

[0095] That is, in the fifth embodiment, similar to the second embodiment, the handle guard 20C is omitted from the housing 20. In the fifth embodiment, the front-rear dimension of the housing 20 is set shorter than that of the first embodiment. The housing 20 has a lifter housing portion 20F similar to that of the second embodiment and a motor housing portion 20B disposed below the lifter housing portion 20F. A feed screw mechanism 50 is accommodated in the lifter housing portion 20F. A motor 40 and a controller 90 are accommodated in the motor housing portion 20B, and the motor 40 is disposed parallel to the lower side of the feed screw mechanism 50. The controller 90 is disposed in front of the motor 40. A battery mounting portion 20D is provided above the rear end of the lifter housing portion 20F, and the battery 24 mounted in the battery mounting portion 20D is disposed above the motor housing portion 20B.

[0096] The grip portion 20A2 extends in the front-rear direction and is disposed above the lifter housing portion 20F and in front of the battery 24. Specifically, the grip portion 20A2 extends in a direction that slopes upward as it approaches the front in a side view. The front end of the grip portion 20A2 is bent diagonally downward and connected to the front end of the lifter housing portion 20F, and the rear end of the grip portion 20A2 is bent downward and connected to the middle portion of the lifter housing portion 20F in the front-rear direction. A trigger 30 that protrudes downward is provided at the front end of the grip portion 20A2.

[0097] Also in the fifth embodiment, the center of gravity G5 of the electric cutter 500 is located at a position overlapping with the blade 60 and the support portion 80A in the vertical direction of the electric cutter 500 in a side view. Specifically, the center of gravity G5 overlaps with the lifter housing portion 20F in a side view, and is located within the range of the width dimension B of the blade 60 and the range of the width dimension A of the support portion 80A in the vertical direction. Therefore, when the electric cutter 500 is in an upright position, the center of gravity G5 of the electric cutter 500 is located vertically below the blade 60 for cutting the workpiece W. This improves the operability of the electric cutter 500, as in the first embodiment.

[0098] In the fifth embodiment, the grip portion 20A2 of the housing 20 is also positioned so as to overlap the center of gravity G5 in the front-rear direction. This allows the operator to grip the grip portion 20A2, which is positioned so as to approximately coincide with the center of gravity G5 in the longitudinal direction of the electric cutter 500, and perform cutting. This further improves the operability of the electric cutter 500.

[0099] In the fifth embodiment, the motor housing 20B is disposed below the lifter housing 20F, and the grip 20A2 and the battery 24 are disposed above the lifter housing 20F and are arranged side by side in the front-to-rear direction. This allows the size of the electric cutter 500 to be reduced in the front-to-rear direction.

[0100] Sixth Embodiment Next, an electric cutter 600 as a work machine according to a sixth embodiment will be described with reference to Figures 14(A) and 14(B). The electric cutter 600 according to the sixth embodiment is configured similarly to the electric cutter 10 according to the first embodiment, except for the following points. In Figures 14(A) and 14(B), the same reference numerals are used to designate components that are configured similarly to the electric cutter 10 according to the first embodiment.

[0101] That is, in the sixth embodiment, the handle guard 20C is omitted from the housing 20. The dimension of the housing 20 in the front-rear direction is set to be longer than that of the first embodiment. The housing 20 has a lifter housing portion 20F that forms the front end of the housing 20, a motor housing portion 20B that forms the middle portion of the housing 20 in the front-rear direction, and a handle housing portion 20A that forms the rear portion of the housing 20. The lifter housing portion 20F is formed in a substantially cylindrical shape that extends in the front-rear direction, and accommodates a feed screw mechanism 50. The motor housing portion 20B accommodates the motor 40, and a lower portion of the motor housing portion 20B protrudes downward beyond the lifter housing portion 20F.

[0102] The grip 20A2 forms the front portion of the handle housing 20A and extends in the front-to-rear direction. A lower portion of the rear end of the handle housing 20A protrudes downward from the handle housing 20A, and a battery attachment section 20D is provided at the rear end of the handle housing 20A. A battery 24 attached to the battery attachment section 20D forms the rear end of the electric cutter 200. A controller 90 is housed in the rear end of the handle housing 20A. A trigger 30 is provided at the front end of the grip 20A2 and protrudes downward from the front end of the grip 20A2. That is, in the electric cutter 600 of the sixth embodiment, the housing 20 protrudes further rearward than in the first embodiment, and the grip 20A2 is located behind the motor 40.

[0103] Also in the sixth embodiment, the center of gravity G6 of the electric cutter 600 is located at a position overlapping with the blade 60 and the support portion 80A in the vertical direction of the electric cutter 600 in a side view. Specifically, the center of gravity G6 overlaps with the lifter housing portion 20F in a side view, and is located within the range of the width dimension B of the blade 60 and the range of the width dimension A of the support portion 80A in the vertical direction. Therefore, when the electric cutter 200 is in an upright position, the center of gravity G6 of the electric cutter 200 is located vertically below the blade 60 for cutting the workpiece W. This improves the operability of the electric cutter 600, as in the first embodiment.

[0104] Furthermore, in the sixth embodiment, the gripping portion 20A2 held by the operator is positioned behind the head 80 and overlaps the support portion 80A of the head 80 as viewed from the front-to-rear direction. Specifically, as viewed from the left-to-right direction, the gripping portion 20A2 is positioned within the width dimension A of the support portion 80A and extends in the front-to-rear direction. In other words, as viewed from the left-to-right direction, the gripping portion 20A2 is positioned vertically at the same position as the support portion 80A. Therefore, as in the first embodiment, when loading a workpiece W, such as a light-weight ceiling material fixed to a ceiling, into the electric cutter 600, the gripping portion 20A2 is positioned vertically below the support portion 80A. As a result, the workpiece W can be easily loaded onto the support portion 80A of the head 80. This improves the operability of the electric cutter 600.

[0105] Also in the sixth embodiment, the trigger 30 is provided at the front end of the grip portion 20A2, and a portion of the trigger 30 overlaps with the support portion 80A when viewed from the front-to-rear direction. Specifically, when viewed from the left-to-right direction, a portion of the trigger 30 is disposed within the width dimension A of the support portion 80A. As a result, as in the first embodiment, the operator can operate the trigger 30 with the hand gripping the grip portion 20A2 while keeping their hand positioned behind the support portion 80A. This further improves the operability of the electric cutter 600.

[0106] In the sixth embodiment, the housing 20 extends in the front-rear direction, and the motor housing 20B, the grip 20A2, and the battery attachment section 20D are arranged side by side in the front-rear direction. The grip 20A2 is located at the rear of the housing 20 (rearward of the center in the front-rear direction). This allows the grip 20A2 to be positioned toward the rear end of the electric cutter 600 while extending the overall length of the electric cutter 600 in the front-rear direction. This allows the grip 20A2 to be positioned vertically lower than in the first embodiment when loading a workpiece W, such as a light-weight ceiling material fixed to a ceiling, into the electric cutter 600. As a result, the operator's lifting distance for the electric cutter 600 can be reduced. This further improves the operability of the electric cutter 600.

[0107] Seventh Embodiment Next, an electric cutter 700 as a work machine according to a seventh embodiment will be described with reference to Figures 15(A) and 15(B). The electric cutter 700 according to the seventh embodiment has the same configuration as the electric cutter 10 according to the first embodiment, except for the following points. In Figures 15(A) and 15(B), the same reference numerals are used to designate components that are configured in the same manner as the electric cutter 10 according to the first embodiment.

[0108] That is, in the seventh embodiment, as in the sixth embodiment, the handle guard 20C is omitted from the housing 20, and the housing 20 has a longer longitudinal dimension than that of the first embodiment. The housing 20 includes a lifter housing portion 20F, a grip portion 20A2 constituting the longitudinal middle portion of the housing 20, and a motor housing portion 20B constituting the rear end of the housing 20, similar to the sixth embodiment. The lifter housing portion 20F constitutes the front end of the housing 20 and houses a feed screw mechanism 50. The motor housing portion 20B houses a motor 40. A battery mounting portion 20D is provided at the rear end of the motor housing portion 20B, and the battery 24 mounted in the battery mounting portion 20D constitutes the rear end of the electric cutter 700. Thus, in the seventh embodiment, the lifter housing portion 20F, the grip portion 20A2, the motor housing portion 20B, and the battery mounting portion 20D are arranged side by side in the longitudinal direction.

[0109] Also in the seventh embodiment, the center of gravity G7 of the electric cutter 700 is located at a position overlapping with the blade 60 and the support portion 80A in the vertical direction of the electric cutter 700 in a side view. Specifically, the center of gravity G7 overlaps with the lifter housing portion 20F in a side view, and is located within the range of the width dimension B of the blade 60 and the range of the width dimension A of the support portion 80A in the vertical direction. Therefore, when the electric cutter 700 is in an upright position, the center of gravity G7 of the electric cutter 700 is located vertically below the blade 60 for cutting the workpiece W. This improves the operability of the electric cutter 700, as in the first embodiment.

[0110] Furthermore, in the seventh embodiment, the gripping portion 20A2 held by the operator is positioned behind the head 80 and overlaps the support portion 80A of the head 80 as viewed from the front-to-rear direction. Specifically, as viewed from the left-to-right direction, substantially the entire gripping portion 20A2 is positioned within the width dimension A of the support portion 80A and extends in the front-to-rear direction. In other words, as viewed from the left-to-right direction, substantially the entire gripping portion 20A2 is positioned vertically at the same position as the support portion 80A. Therefore, as in the first embodiment, when loading a workpiece W, such as a light-weight ceiling material fixed to a ceiling, into the electric cutter 700, the gripping portion 20A2 is positioned vertically below the support portion 80A. As a result, the workpiece W can be easily loaded onto the support portion 80A of the head 80. This improves the operability of the electric cutter 700.

[0111] Also in the seventh embodiment, the trigger 30 is provided at the front end of the grip portion 20A2, and a portion of the trigger 30 overlaps with the support portion 80A when viewed from the front-to-rear direction. Specifically, when viewed from the left-to-right direction, a portion of the trigger 30 is disposed within the width dimension A of the support portion 80A. As a result, as in the first embodiment, the operator can operate the trigger 30 with the hand gripping the grip portion 20A2 while keeping their hand positioned behind the support portion 80A. This further improves the operability of the electric cutter 700.

[0112] In the seventh embodiment, the housing 20 extends in the front-rear direction, and the lifter housing 20F, the grip 20A2, the motor housing 20B, and the battery attachment section 20D are arranged side by side in the front-rear direction. The grip 20A2 is located at the rear of the housing 20 (rearward of the center in the front-rear direction). Therefore, as in the sixth embodiment, the size of the electric cutter 700 can be extended in the front-rear direction while the grip 20A2 is positioned toward the rear end of the electric cutter 700. This allows the grip 20A2 to be positioned vertically lower than in the first embodiment when loading a workpiece W, such as a light-weight ceiling material fixed to a ceiling, onto the electric cutter 700. As a result, the operator's lifting distance for the electric cutter 700 can be reduced. This further improves the operability of the electric cutter 700.

[0113] Eighth Embodiment Next, an electric cutter 800 as a work machine according to an eighth embodiment will be described with reference to Figures 16(A) and 16(B). The electric cutter 800 according to the eighth embodiment has the same configuration as the electric cutter 10 according to the first embodiment, except for the following points. In Figures 16(A) and 16(B), the same reference numerals are used to designate components that are configured in the same way as the electric cutter 10 according to the first embodiment.

[0114] That is, in the eighth embodiment, the housing 20 includes a lifter housing portion 20F similar to those of the sixth and seventh embodiments, a motor housing portion 20B constituting the longitudinally intermediate portion of the housing 20, and a handle housing portion 20A constituting the rear end of the housing 20. The lifter housing portion 20F constitutes the front end of the housing 20 and accommodates a feed screw mechanism 50. The motor housing portion 20B protrudes downward from the rear end of the lifter housing portion 20F and accommodates a motor 40. A battery mounting portion 20D is also provided at the rear end of the lifter housing portion 20F. The battery mounting portion 20D protrudes upward from the lifter housing portion 20F, and the battery 24 mounted in the battery mounting portion 20D protrudes above the battery mounting portion 20D. When viewed from the left side, the handle housing portion 20A extends in a direction that slopes downward toward the rear. The handle guard 20C extends rearward from the lower end of the motor housing 20B, and the rear end of the handle guard 20C is connected to the lower end of the handle housing 20A. The controller 90 is housed in the front end of the handle housing 20A.

[0115] Also in the eighth embodiment, the center of gravity G8 of the electric cutter 800 is located at a position overlapping with the blade 60 and the support portion 80A in the vertical direction of the electric cutter 800 in a side view. Specifically, the center of gravity G8 overlaps with the lifter housing portion 20F in a side view, and is located within the range of the width dimension B of the blade 60 and the range of the width dimension A of the support portion 80A in the vertical direction. Therefore, when the electric cutter 800 is in an upright position, the center of gravity G8 of the electric cutter 800 is located vertically below the blade 60 for cutting the workpiece W. This improves the operability of the electric cutter 800, as in the first embodiment.

[0116] Furthermore, in the eighth embodiment, the front end of the gripping portion 20A2, which is held by the operator, is positioned behind the head unit 80 and overlaps with the support portion 80A of the head unit 80 as viewed from the front-to-rear direction. Specifically, as viewed from the left-to-right direction, the front end of the gripping portion 20A2 is positioned within the width dimension A of the support portion 80A and extends in a direction that slopes downward as it approaches the rear. In other words, as viewed from the left-to-right direction, the front end of the gripping portion 20A2 is positioned vertically at the same position as the support portion 80A. Therefore, as in the first embodiment, when loading a workpiece W, such as a light-weight ceiling material fixed to a ceiling, into the electric cutting machine 800, the front end of the gripping portion 20A2 is positioned vertically below the support portion 80A. As a result, the operator can easily load the workpiece W onto the support portion 80A of the head unit 80 by gripping the front end of the gripping portion 20A2. This improves the operability of the electric cutting machine 800. Furthermore, because the grip portion 20A2 is inclined in the front-to-rear direction, the weight of the head portion 80 can be supported by the palm of the hand when the head portion 80 is facing upward, resulting in a configuration that reduces fatigue.

[0117] In the eighth embodiment, the trigger 30 is provided at the front end of the grip portion 20A2, and a portion of the trigger 30 overlaps with the support portion 80A when viewed from the front-to-rear direction. Specifically, when viewed from the left-to-right direction, a portion of the trigger 30 is located within the width dimension A of the support portion 80A. As a result, similar to the first embodiment, the operator can operate the trigger 30 with the hand gripping the grip portion 20A2 while keeping their hand positioned behind the support portion 80A. This further improves the operability of the electric cutter 800.

[0118] In the eighth embodiment, the housing 20 extends in the front-to-rear direction, and the gripping portion 20A2 forms the rear end of the housing 20. Therefore, when loading a workpiece W, such as a light-weight ceiling material fixed to a ceiling or the like, onto the electric cutter 800, the gripping portion 20A2 can be positioned vertically lower than in the first embodiment. As a result, the amount of lifting required by the operator for the electric cutter 800 can be reduced. This further improves the operability of the electric cutter 800.

[0119] In the eighth embodiment, the motor housing portion 20B and the battery attachment portion 20D are disposed in the longitudinally intermediate portion of the housing 20 and are arranged side by side in the vertical direction. This allows the motor 40 and the battery 24 to be concentrated in the longitudinally intermediate portion of the housing 20, while the grip portion 20A2 can be set at the rear end of the housing 20.

[0120] Ninth Embodiment Next, an electric cutter 900 as a work machine according to a ninth embodiment will be described with reference to Figures 17(A) and 17(B). The electric cutter 900 according to the ninth embodiment is configured similarly to the electric cutter 10 according to the first embodiment, except for the following points. In Figures 17(A) and 17(B), the same reference numerals are used to designate components that are configured similarly to the electric cutter 10 according to the first embodiment.

[0121] That is, in the ninth embodiment, the housing 20 extends in the front-rear direction, and the dimension of the housing 20 in the front-rear direction is set to be longer than that of the first embodiment. The housing 20 has a lifter housing portion 20F similar to that of the eighth embodiment, a motor housing portion 20B that forms the middle portion of the housing 20 in the front-rear direction, and a grip portion 20A2 that forms the rear end portion of the housing 20.

[0122] The lifter housing portion 20F forms the front end portion of the housing 20, and accommodates a feed screw mechanism 50. The motor housing portion 20B is disposed rearward of the lifter housing portion 20F, with a lower portion of the motor housing portion 20B protruding downward beyond the lifter housing portion 20F, and accommodates a motor 40. A battery mounting portion 20D is provided at the rear end portion of the motor housing portion 20B, and a battery 24 protrudes rearward from the battery mounting portion 20D. The motor housing portion 20B accommodates a controller 90.

[0123] The grip portion 20A2 is disposed rearward and spaced apart from the battery 24, and extends substantially vertically. The housing 20 has a pair of upper and lower handle guards 20C, which extend forward from both longitudinal ends of the grip portion 20A2 and are connected to the rear end of the motor housing portion 20B.

[0124] Also in the ninth embodiment, the center of gravity G9 of the electric cutter 900 is located at a position overlapping with the blade 60 and the support portion 80A in the vertical direction of the electric cutter 900 in a side view. Specifically, the center of gravity G9 overlaps with the lifter housing portion 20F in a side view, and is located within the range of the width dimension B of the blade 60 and the range of the width dimension A of the support portion 80A in the vertical direction. Therefore, when the electric cutter 900 is in an upright position, the center of gravity G9 of the electric cutter 900 is located vertically below the blade 60 for cutting the workpiece W. This improves the operability of the electric cutter 900, as in the first embodiment.

[0125] Furthermore, in the ninth embodiment, the upper portion of the gripping portion 20A2 held by the operator is positioned behind the head unit 80 and overlaps with the support portion 80A of the head unit 80 as viewed from the front-to-rear direction. Specifically, as viewed from the left-to-right direction, the upper portion of the gripping portion 20A2 is positioned within the width dimension A of the support portion 80A, and the gripping portion 20A2 extends vertically. In other words, as viewed from the left-to-right direction, the upper portion of the gripping portion 20A2 is positioned vertically at the same position as the support portion 80A. Therefore, as in the first embodiment, when loading a workpiece W, such as a light-weight ceiling material fixed to a ceiling, into the electric cutter 900, the upper portion of the gripping portion 20A2 is positioned vertically below the support portion 80A. As a result, by gripping the upper portion of the gripping portion 20A2, the operator can easily load the workpiece W onto the support portion 80A of the head unit 80. This improves the operability of the electric cutter 900.

[0126] In the ninth embodiment, the trigger 30 is provided at the upper end of the grip portion 20A2, and a portion of the trigger 30 overlaps with the support portion 80A when viewed from the front-to-back direction. Specifically, when viewed from the left-to-right direction, a portion of the trigger 30 is located within the width dimension A of the support portion 80A (at the same position as the support portion 80A in the up-down direction). As a result, as in the first embodiment, the operator can operate the trigger 30 with the hand gripping the grip portion 20A2 while keeping their hand positioned behind the support portion 80A. This further improves the operability of the electric cutting machine 900.

[0127] In the ninth embodiment, the housing 20 extends in the front-to-rear direction, and the gripping portion 20A2 forms the rear end of the housing 20. Therefore, as in the eighth embodiment, when loading a workpiece W, such as a light-weight ceiling material fixed to a ceiling or the like, into the electric cutter 900, the gripping portion 20A2 can be positioned vertically lower than in the first embodiment. As a result, the amount of lifting required by the operator for the electric cutter 900 can be reduced.

[0128] In the ninth embodiment, the motor housing portion 20B and the battery attachment portion 20D are arranged side by side in the front-to-rear direction at the middle of the housing 20. As a result, similar to the eighth embodiment, the motor 40 and the battery 24 can be arranged together in the middle of the housing 20 in the front-to-rear direction, while the grip portion 20A2 can be set at the rear end of the housing 20.

[0129] Tenth Embodiment Next, an electric cutter 1000 as a work machine according to a tenth embodiment will be described with reference to Figures 18(A) and 18(B). The electric cutter 1000 according to the tenth embodiment has the same configuration as the electric cutter 10 according to the first embodiment, except for the following points. In Figures 18(A) and 18(B), the same reference numerals are used to designate components that are configured in the same way as the electric cutter 10 according to the first embodiment.

[0130] That is, in the tenth embodiment, the housing 20 extends in the front-rear direction, and the dimension of the housing 20 in the front-rear direction is set to be longer than that of the first embodiment. The housing 20 has a lifter housing portion 20F similar to that of the ninth embodiment, a motor housing portion 20B that forms the middle portion of the housing 20 in the front-rear direction, and a grip portion 20A2 that forms the rear end portion of the housing 20.

[0131] The lifter housing portion 20F forms the front end portion of the housing 20 and accommodates a feed screw mechanism 50. The motor housing portion 20B is disposed rearward of the lifter housing portion 20F, with the lower portion of the motor housing portion 20B projecting downwardly beyond the lifter housing portion 20F. The motor housing portion 20B accommodates the motor 40 and the controller 90. A battery mounting portion 20D projecting downward is provided at the rear end portion of the lifter housing portion 20F, and the battery 24 projects downward from the battery mounting portion 20D.

[0132] The grip portion 20A2 is spaced apart from the rear of the motor housing portion 20B and extends substantially vertically. The housing 20 has a pair of upper and lower handle guards 20C that extend forward from both longitudinal ends of the grip portion 20A2 and are connected to the rear end of the motor housing portion 20B.

[0133] Also in the tenth embodiment, the center of gravity G10 of the electric cutter 1000 is located at a position overlapping with the blade 60 and the support portion 80A in the vertical direction of the electric cutter 1000 in a side view. Specifically, the center of gravity G10 overlaps with the lifter housing portion 20F in a side view, and is located within the range of the width dimension B of the blade 60 and the range of the width dimension A of the support portion 80A in the vertical direction. Therefore, when the electric cutter 1000 is in an upright position, the center of gravity G10 of the electric cutter 1000 is located vertically below the blade 60 that cuts the workpiece W. This improves the operability of the electric cutter 1000, as in the first embodiment.

[0134] Furthermore, in the tenth embodiment, as in the ninth embodiment, the upper portion of the gripping portion 20A2 held by the operator is positioned behind the head portion 80 and overlaps with the support portion 80A of the head portion 80 as viewed from the front-to-rear direction. Specifically, as viewed from the left-to-right direction, the upper portion of the gripping portion 20A2 is positioned within the width dimension A of the support portion 80A and extends in a direction that slopes downward as it approaches the rear. Therefore, as in the ninth embodiment, the operator can easily set the workpiece W on the support portion 80A of the head portion 80 by grasping the upper portion of the gripping portion 20A2. As a result, the operability of the electric cutting machine 1000 can be improved.

[0135] In the tenth embodiment, similarly to the ninth embodiment, the trigger 30 is provided at the upper end of the grip portion 20A2, and the trigger 30 overlaps with the support portion 80A when viewed from the front-to-rear direction. Specifically, when viewed from the left-to-right direction, the trigger 30 is disposed within the width dimension A of the support portion 80A. As a result, similarly to the ninth embodiment, the operator can operate the trigger 30 with the hand gripping the grip portion 20A2 while keeping their hand positioned behind the support portion 80A. This further improves the operability of the electric cutter 1000.

[0136] In the tenth embodiment, the housing 20 extends in the front-to-rear direction, and the gripping portion 20A2 forms the rear end of the housing 20. Therefore, as in the ninth embodiment, when loading a workpiece W, such as a light-weight ceiling material fixed to a ceiling or the like, onto the electric cutter 1000, the gripping portion 20A2 can be positioned vertically downward. As a result, the amount of lifting required by the operator for the electric cutter 1000 can be reduced.

[0137] In the tenth embodiment, the motor housing portion 20B and the battery attachment portion 20D are arranged side by side in the front-to-rear direction at the middle of the housing 20. This allows the motor 40 and the battery 24 to be arranged together in the middle of the housing 20 in the front-to-rear direction, as in the fifth embodiment, while the grip portion 20A2 can be set at the rear end of the housing 20.

[0138] 10... Electric cutting machine (work machine), 20... Housing, 20A... Handle housing portion (gripping portion), 20A2... Grip portion, 22... Battery terminal (power supply portion), 40... Motor, 60... Blade (cutting tool), 60A... Blade portion, 60B... Tip portion of blade portion, 80A... Support portion, 200... Electric cutting machine (work machine), 300... Electric cutting machine (work machine), 400... Electric cutting machine (work machine), 500... Electric cutting machine (work machine), G1... Center of gravity, G2... Center of gravity, G3... Center of gravity, G4... Center of gravity, G5... Center of gravity, G6... Center of gravity, G7... Center of gravity, G8... Center of gravity, G9... Center of gravity, G10... Center of gravity, W... Workpiece (lightweight steel beam material)

Claims

1. A housing extending in a first direction; a cutting tool provided on one side of the housing in the first direction so as to be reciprocable in the first direction, formed in a plate shape with a second direction perpendicular to the first direction as a width direction and a third direction perpendicular to the first direction and the second direction as a plate thickness direction, and configured to cut a U-shaped workpiece by moving to one side in the first direction; Equipped with a support portion for supporting the workpiece is provided on one side of the cutting tool in the first direction; a V-shaped blade portion that is convex toward one side in the first direction when viewed from the third direction is formed at one end of the cutting tool in the first direction, In the second direction, a tip end of the blade portion is disposed at a position offset to one side in the second direction with respect to a center portion of the support portion in the second direction, A work machine in which, when viewed from the third direction, the center of gravity is located at a position that overlaps with the cutting tool in the second direction, and the center of gravity is located at a position offset to the other side in the second direction relative to the center of the support part in the second direction.

2. The work machine according to claim 1 , wherein the housing has a grip portion, and at least a portion of the grip portion is disposed at a position overlapping the center of gravity in the first direction.

3. The work machine according to claim 2 , wherein the grip portion extends in the first direction.

4. The gripping portion is provided with an operating portion for instructing the cutting tool to start moving, The work machine according to claim 3 , wherein the center of gravity is located on the other side in the first direction with respect to the operation unit.

5. The housing accommodates a motor for reciprocating the cutting tool, The work machine according to claim 1 , wherein the motor is disposed at a position offset to one side in the second direction with respect to a center of the support part in the second direction.

6. 6. The work machine according to claim 5, wherein the housing is provided with a power supply unit for supplying power to the motor, the power supply unit being positioned at a position offset to the other side in the second direction with respect to the center of the second direction on the support portion.

7. 3. The work machine according to claim 2, wherein, when viewed from the third direction, a part of the grip portion is located outside an imaginary circle that has a center at a center of the support portion in the second direction and passes through the center of gravity.

8. The work machine according to claim 7 , wherein a part of the grip portion is positioned so as to overlap with the support portion when viewed from the first direction.

9. A work machine as described in claim 1, configured so that the cutting tool and the center of gravity overlap when viewed from the first direction.

10. an operation unit is provided on the gripping portion to instruct the cutting tool to start moving, The work machine according to claim 2 , wherein at least a portion of the operation portion overlaps with the support portion when viewed from the first direction.

11. The work machine according to claim 10 , wherein the grip portion extends in the first direction, and the operation portion is disposed at one end of the grip portion in the first direction.

12. a housing extending in the first direction and disposed on the other side of the cutting tool in the first direction; a motor for driving the cutting accessory; Equipped with the grip portion constitutes one side portion of the housing in the first direction, 3. The working machine according to claim 2, wherein the other end of the housing in the first direction is configured as a motor housing portion that houses the motor.

13. A direction perpendicular to the first direction is a second direction, The work machine according to claim 12, wherein the motor housing portion is provided with a battery mounting portion for mounting a battery that supplies power to the motor, the battery mounting portion being positioned on one side of the motor in the second direction.

14. The housing has a guard portion extending in the first direction, The work machine according to claim 13 , wherein the guard portion is disposed on one side of the grip portion in the second direction and on one side of the battery attachment portion in the first direction.

15. A cutting tool configured to be reciprocated between an initial position and a processing position by a motor; a processing unit having a support portion that supports a U-shaped workpiece by a plurality of cutout portions arranged at predetermined intervals; A grip portion extending in a first direction and including an operation portion for turning the motor on and off; a battery for supplying power to the motor; a motor housing for holding the motor and the battery; Equipped with the processed portion is provided on one side of the grip portion in the first direction, and the motor housing is provided on the other side of the grip portion in the first direction, A work machine configured so that the center of gravity when the battery is held is located between the processing portion and the motor housing in the first direction.

16. At least a portion of a drive shaft for transmitting power of the motor to the cutting blade is accommodated inside the gripping portion, The drive shaft extends in the first direction, 16. The work machine according to claim 15, wherein the center of the motor is offset from the axis of the drive shaft in a second direction intersecting the first direction, and the center of gravity is offset from the axis of the drive shaft in the second direction.

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