Work machine

Abstract

A work machine with good workability is provided. In a shearing tool 10 serving as the work machine, a head part 70 includes a support head part 75 and a support adapter 78. The head part 70 is configured to be switchable between a first state for supporting a first light ceiling material 90 and a second state for supporting a second light ceiling material 92 having a height dimension different from that of the first light ceiling material 90. Specifically, when the head part 70 is switched from the first state to the second state, a second support position P2 is changed to the front side, increasing a distance L. Therefore, even when cutting the first light ceiling material 90 and the second light ceiling material 92 having different height dimensions, both the light ceiling materials can be supported at two different positions in the front-rear direction. As a result, for example, it is not necessary to prepare a plurality of work machines that handle light ceiling materials having different height dimensions. The workability of the shearing tool 10 can therefore be improved.

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 holder is provided behind the backing plate. A housing is provided behind the holder, and the housing includes a motor chamber extending in the front-to-rear direction and a handle extending in a direction intersecting the motor chamber. The backing plate supports a light-gauge steel material, and by operating a main switch on the handle, the cutting blade moves forward from the holder, clamping the light-gauge steel material between the cutting blade and the backing plate. This allows the light-gauge steel material to be cut.

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

[0004] However, with the above-mentioned power reciprocating tool, the height dimension of the ceiling material that can be supported by the backing plate (the direction in which the cutting blade moves, i.e., the dimension in the front-to-back direction) is only one dimension. In other words, the above-mentioned power reciprocating tool is not suitable for cutting ceiling materials of different heights. For this reason, for example, if two types of power reciprocating tools are prepared for ceiling materials of different heights and the power reciprocating tool is used depending on the height of the ceiling material, the cutting work may become complicated and the workability may deteriorate.

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

[0006] One or more embodiments of the present invention are a work machine comprising a support mechanism that supports plasterboard material, and a cutting blade that is configured to be movable in a predetermined direction and cuts the plasterboard material when moved to one side in the predetermined direction, wherein the support mechanism is configured to support the plasterboard material from one side in the predetermined direction at a first support position and a second support position that is located to one side of the predetermined direction from the first support position, and is configured to be able to change the distance between the first support position and the second support position in the predetermined direction.

[0007] In one or more embodiments of the present invention, the support mechanism is configured to include a support head portion on which the light-weight ceiling material is set, and a support position change member attached to the support head portion so as to be able to support the light-weight ceiling material, and the distance between the first support position and the second support position in the specified direction is changed depending on the attachment state of the support position change member to the support head portion.

[0008] One or more embodiments of the present invention are directed to a work machine in which the support position changing member supports the light-weight ceiling material at the first support position or the second support position.

[0009] One or more embodiments of the present invention are a work machine in which the support position changing member is attached to the support head portion so as to be movable between a first position and a second position, and the distance between the first support position and the second support position in the specified direction is changed by moving the support position changing member to the first position or the second position.

[0010] In one or more embodiments of the present invention, the support position changing member is attached to the support head portion so as to be movable in a direction intersecting the predetermined direction.

[0011] In one or more embodiments of the present invention, the support position changing member is attached to the support head portion so as to be rotatable about an axis extending in a direction intersecting the predetermined direction.

[0012] One or more embodiments of the present invention are a work machine in which, when the support position change member is located at the first position, the support head portion supports the plasterwork material at the first support position and the support position change member supports the plasterwork material at the second support position, and when the support position change member is located at the second position, the second support position is changed to one side in a predetermined direction and the support head portion supports the plasterwork material at the first support position and the second support position.

[0013] One or more embodiments of the present invention are a work machine in which, when the support position change member moves from the first position to the second position, the support position change member moves relative to the support head portion toward one side in the specified direction.

[0014] In one or more embodiments of the present invention, the support position changing member is configured to be removable from the support head portion, and by removing the support position changing member from the support head portion, the distance between the first support position and the second support position in the specified direction is changed in the work machine.

[0015] One or more embodiments of the present invention are a work machine in which, when the support position change member is attached to the support head portion, the support head portion supports the plasterwork material at the first support position and the support position change member supports the plasterwork material at the second support position, and when the support position change member is detached from the support head portion, the support head portion supports the plasterwork material at the first support position and the second support position and the second support position is changed to one side in a predetermined direction.

[0016] One or more embodiments of the present invention are a work machine in which, when the support position change member is attached to the support head portion, the support position change member supports the plasterwork material at the first support position and the support head portion supports the plasterwork material at the second support position, and when the support position change member is detached from the support head portion, the support head portion supports the plasterwork material at the first support position and the second support position and the first support position is changed to one side in a predetermined direction.

[0017] One or more embodiments of the present invention are a work machine comprising a motor that is driven to move the cutting blade, and a controller that controls the driving of the motor, wherein the controller detects when the cutting blade has completed cutting the light-weight ceiling material, and when the cutting blade has completed cutting the light-weight ceiling material, the controller stops or reverses the motor.

[0018] One or more embodiments of the present invention are a work machine capable of cutting first and second light-weight ceiling materials that have different dimensions in a predetermined direction, and include a support mechanism that supports the first and second light-weight ceiling materials at two different positions in the predetermined direction, and a cutting blade that is configured to be movable in the predetermined direction and cuts the first or second light-weight ceiling material supported by the support mechanism when moving to one side in the predetermined direction, and the support mechanism is configured to be switchable between a first state in which it supports the first light-weight ceiling material and a second state in which it supports the second light-weight ceiling material.

[0019] According to one or more embodiments of the present invention, a work machine with good workability can be provided.

[0020] 1 is a cross-sectional view from the right side showing the inside of the shearing tool according to the present embodiment; FIG. 2 is an enlarged view showing the head portion of the shearing tool shown in FIG. 1; FIG. 3 is a side view showing the state in which the head portion shown in FIG. 2 has been switched from the first state to the second state; FIG. 4 is a cross-sectional view (cross-sectional view taken along line 4-4 in FIG. 3) showing the periphery of the moderation mechanism portion shown in FIG. 3; FIG. 5 is a cross-sectional view (cross-sectional view taken along line 5-5 in FIG. 3) showing the attachment state of the support adapter shown in FIG. 3 to the support head portion shown in FIG. 3; FIG. 6A is a cross-sectional view (cross-sectional view taken along line 6A-6A in FIG. 3) showing the attachment state of the support adapter and the support head portion using the lock shaft shown in FIG. 3; and FIG. 6B is a cross-sectional view (cross-sectional view taken along line 6A-6A in FIG. 3) showing the state in which the lock shaft shown in FIG. 3 has been moved to the unlock position shown in FIG. 3; 8A is a side view from the right side showing the periphery of the lock shaft in the head unit modified example 1 in a second state, and FIG. 8B is a cross-sectional view from the front (cross-sectional view taken along line 7B-7B in FIG. 7A) showing the attachment state of the support adapter and the support head unit using the lock shaft in FIG. 8A. (A) is a side view from the right side showing the first state of the head unit modified example 2, and FIG. 8B is a side view showing the state in which the support adapter shown in FIG. 8A has been removed from the support head unit and the head unit has been switched to the second state. (B) is a cross-sectional view from below showing the attachment state of the support adapter shown in FIG. 8A to the support head unit. (A) is a side view from the right side showing the first state of the head unit modified example 3, and FIG. 8B is a side view showing the state in which the support adapter shown in FIG. 8A has been removed from the support head unit and the head unit has been switched to the second state. 12A is a cross-sectional view (cross-sectional view taken along line 11A-11A in FIG. 12A) seen from below showing the state in which the support adapter is attached to the support head portion by the connecting mechanism portion shown in FIG. 10A, (B) is a cross-sectional view showing the state in which the stopper plate of the connecting mechanism portion shown in (A) has been rotated, and (C) is a cross-sectional view showing the state in which the connecting mechanism portion shown in (B) has been removed from the support head portion. 12A is a side view (right side) showing a first state of the fourth modified example of the head portion, and (B) is a cross-sectional view (cross-sectional view taken along line 12B-12B in FIG. 12A) seen from below showing the state in which the support adapter shown in (A) is attached to the support head portion.13A is a side view of the head unit in a second state according to a fourth modification, as viewed from the right side; and FIG. 13B is a cross-sectional view (cross-sectional view taken along line 13B-13B in FIG. 13A) from below showing the state in which the support adapter shown in FIG. 13A is attached to the support head unit. (A) is a side view of the head unit in a first state according to a fifth modification, as viewed from the right side; and (B) is a side view showing the state in which the attachment position of the support adapter shown in FIG. 13A has been changed to switch the head unit to the second state. (A) is a side view of another example in which the attachment location of the support adapter to the support head unit in the fifth modification, as viewed from the left side; and (B) is a cross-sectional view taken along line 16A-16A in FIG. 13A; and (C) is an enlarged view of the area circled by the dashed dotted line in FIG. 13A. (A) is a side view from the left side showing the second state of head portion variant 6, (B) is a cross-sectional view of 17A-17A shown in (A), and (C) is an enlarged view of the area surrounded by the dotted-dash circle in (B).

[0021] 1 to 6, a shearing tool 10 as a work machine according to this embodiment will be described. Note that arrows UP, FR, and RH, as appropriate shown in the drawings, respectively indicate the upper side, front side, and right side of the shearing tool 10. In the following description, when the up-down, front-rear, and left-right directions are used, they refer to the up-down, front-rear, and left-right directions of the shearing tool 10 unless otherwise specified.

[0022] As shown in Figures 1 to 3, the shearing tool 10 is configured as an electric tool that cuts a first light-weight ceiling material 90 or a second light-weight ceiling material 92, which are light-weight structural steel. The first light-weight ceiling material 90 and the second light-weight ceiling material 92 have different height dimensions. In other words, the shearing tool 10 is configured to be able to process two types of light-weight ceiling material with different height dimensions. The first light-weight ceiling material 90 and the second light-weight ceiling material 92 are formed in the shape of long columns, and when viewed in the longitudinal direction, they are formed in a generally U-shape that is open on one side in the height direction of the first light-weight ceiling material 90 and the second light-weight ceiling material 92. Specifically, the first ceiling material 90 (second ceiling material 92) has a bottom wall 90A (bottom wall 92A) whose thickness direction is the height direction, and a side wall 90B (side wall 92B) extending from both ends of the bottom wall 90A (bottom wall 92A) to one side in the height direction (see Figures 2 and 3). The height of the side wall 92B of the second ceiling material 92 is higher than the height of the side wall 90B of the first ceiling material 90.

[0023] The shearing tool 10 includes a housing 20, a motor 40, a feed screw mechanism 50 (broadly understood as a movement mechanism), a blade 60 as a cutting blade, a controller 64, and a head 70 as a support mechanism. When cutting a first plasterwork material 90 or a second plasterwork material 92 using the shearing tool 10, the first plasterwork material 90 (second plasterwork material 92) is set on the head 70 with one vertical side of the first plasterwork material 90 (second plasterwork material 92) aligned with the front of the shearing tool 10. The blade 60 and the head 70 then clamp and shear the first plasterwork material 90 (second plasterwork material 92) in the front-to-rear direction, thereby cutting the first plasterwork material 90 (second plasterwork material 92). Each component of the shearing tool 10 is described below.

[0024] (Regarding the Housing 20) As shown in Fig. 1, the housing 20 forms the outer shell of the shearing tool 10 excluding the front end portion, 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 substantially rectangular tubular shape that extends in the front-to-rear direction. A pair of protruding portions 20C that protrude upward and downward are formed at the front end portion of the handle housing portion 20A.

[0025] A handle guard 20D is provided below the handle housing 20A. The handle guard 20D is formed in a generally rectangular tubular shape extending in the front-to-rear direction. The front end of the handle guard 20D is bent upward and connected to the lower protrusion 20C, and the rear end of the handle guard 20D is bent diagonally upward and rearward and connected to the rear end of the handle housing 20A. The portion of the handle housing 20A between the front and rear ends of the handle guard 20D forms a grip 20E to be gripped by the operator.

[0026] A trigger 30 is provided at the front end of the grip portion 20E 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 20E so as to be pulled upward. A trigger switch 32 is provided at the front end of the handle housing portion 20A, below the front end of the trigger 30. When the trigger 30 is pulled, the trigger switch 32 switches from off to on, and when the trigger 30 is released, the trigger switch 32 switches from on to off. The trigger switch 32 is electrically connected to a controller 64, which will be described later, and outputs an output signal to the controller 64 in response to the pulling of the trigger 30.

[0027] A support guide 34 is provided at the front end of the handle housing portion 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 support guide 34 is rotatably supported by the handle housing portion 20A, and the front portion of the support guide 34 protrudes forward from the housing 20. A pair of upper and lower slits 34A are formed in the front portion of the support guide 34 for arranging a blade 60, which will be described later. The slits 34A extend in the front-to-rear direction and penetrate in the up-down direction, with the front end of the slit 34A open to the front.

[0028] The motor housing 20B is formed in a generally hollow, flat shape with its thickness extending in the left-right direction. A battery 36 is detachably attached to the lower end of the motor housing 20B, behind the handle guard 20D, and the battery 36 is electrically connected to a controller 64, which will be described later.

[0029] (Regarding the motor 40) The motor 40 is configured as a brushless motor and is housed in 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 a controller 64 (described later) and is driven under the control of the controller 64.

[0030] (Regarding the Feed Screw Mechanism 50) The feed screw mechanism 50 is configured to include a transmission gear 51, a drive shaft 53, a lifter 55, and a lifter detection switch 58 for detecting the initial position of the lifter 55.

[0031] 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. External teeth are formed on the outer periphery of the front portion of the transmission gear 51, and these external teeth mesh with the pinion gear 40B of the drive shaft 40A.

[0032] 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. A male thread 53A is formed on the outer periphery of the drive shaft 53, except for the rear end portion.

[0033] 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 nut portion 57 that forms the rear end of the lifter 55. The nut 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 nut portion 57. The front portion of the drive shaft 53 is inserted into the nut portion 57, and the male thread 53A of the drive shaft 53 and the female thread 57A of the nut 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.

[0034] 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 nut part 57, and the lifter body 56 and the nut part 57 are connected so as not to move relative to each other. The front end of the lifter body 56 is inserted into the support guide 34 and is supported by the support guide 34 so as to be able to move relatively in the front-rear direction.

[0035] As a result, when the drive shaft 53 is rotated by the drive of the motor 40, the lifter 55 moves in the front-to-rear direction due to the threaded engagement between the drive shaft 53 and the lifter 55. Specifically, the lifter 55 moves back and forth between an initial position (the position shown by the solid line in FIG. 1) and a stop position (the position shown by the two-dot chain line in FIG. 1). In the initial position of the lifter 55, the front portion of the drive shaft 53 is inserted into the interior of the lifter body 56 so as to be relatively movable. In addition, the outer periphery of the rear end of the nut portion 57 is configured as a detection target portion 57B.

[0036] The lifter detection switch 58 is configured as a lever-type microswitch and is housed in the rear end of the handle guard 20D. 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 20F formed in the lower end of the outer periphery of the handle housing 20A. The ball hole 20F penetrates in the vertical direction, and the diameter of the ball hole 20F 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 20F. 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. On the other hand, when the lifter 55 is in the initial position, the detected portion 57B of the lifter 55 presses the lever portion of the lifter detection switch 58 downward via the ball 59, and the lifter detection switch 58 switches from OFF to ON. The lifter detection switch 58 is electrically connected to the controller 64 and outputs a detection signal to the controller 64.

[0037] (Regarding the Blade 60) The blade 60 is formed in a generally rectangular plate shape with its thickness extending in the left-right direction and its length extending in the front-rear direction. The rear end of the blade 60 is fixed to the front end of the lifter 55 with a screw 61. This allows the blade 60 to move integrally with the lifter 55 between an initial position (the position indicated by the solid line in FIG. 1 ) and a stop position (the position indicated by the two-dot chain line in FIG. 1 ). The rear end portion of the blade 60 is inserted into the slit 34A of the support guide 34. The front end of the blade 60 is formed with a blade portion 60A, which is formed in a generally V-shape that protrudes forward when viewed from the left-right direction. Furthermore, a pair of upper and lower stopper pieces 60B are formed at the rear end of the blade 60.

[0038] When the blade 60 is in its initial position, the stopper piece 60B is positioned vertically outward of the support guide 34 within the handle housing 20A. When the blade 60 is in its initial position, it is positioned adjacent to the front of the housing 20 and behind the first ceiling material 90 (second ceiling material 92). When the blade 60 moves forward from its initial position, it clamps the first ceiling material 90 (second ceiling material 92) from both front and rear sides together with the head unit 70 (described later), thereby cutting the first ceiling material 90 (second ceiling material 92). When the blade 60 is stopped, the controller 64 (described later) completes the cutting of the first ceiling material 90 (second ceiling material 92).

[0039] (Regarding the head unit 70) As shown in Figures 1 to 3, the head unit 70 is configured as a mechanism that supports the first ceiling material 90 or the second ceiling material 92 during cutting. Therefore, the head unit 70 is configured to be switchable between a first state (the state shown in Figures 1 and 2) in which it supports the first ceiling material 90 and a second state (the state shown in Figure 3) in which it supports the second ceiling material 92. The head unit 70 is configured to include a base head unit 71, a support head unit 75, and a support adapter 78 as a support position changing member.

[0040] (Regarding the Base Head 71) The base head 71 includes a blade holder 72 and a main plate 74. The blade holder 72 is composed of a pair of left and right holder plates 73 (only the left holder plate 73 is shown in FIGS. 1 and 2). The holder plates 73 are made of metal and are formed into a generally rectangular plate shape with a thickness in the left-right direction. The pair of holder plates 73 are arranged opposite each other with a predetermined gap in the left-right direction, and the blade 60 is positioned between the pair of holder plates 73. As a result, the blade holder 72 covers the blade 60 from both the left and right sides, restricting the rotation of the lifter 55 and the blade 60 when the drive shaft 53 rotates and guiding the reciprocating movement of the blade 60 in the front-to-rear direction. Note that the rearward protrusion length of the stopper piece 60B of the blade 60 is set so that the blade holder 72 covers the stopper piece 60B of the blade 60 from both the left and right sides even when the blade 60 is stopped.

[0041] The lower ends of the pair of holder plates 73 are connected to each other by a pair of front and rear bolts BL1. A main plate 74 (described later) is disposed between the upper ends of the pair of holder plates 73. The pair of holder plates 73 are fastened and fixed by a pair of front and rear bolts BL2, sandwiching the main plate 74 from the outside in the left-right direction. A holder connecting portion 73A is formed in the middle of the holder plate 73 in the up-down direction. When viewed from the front, the holder connecting portion 73A is formed in a generally arc-shaped configuration that protrudes outward in the left-right direction. The holder connecting portion 73A sandwiches the front portion of the support guide 34 from the outside in the left-right direction, connecting the holder plate 73 to the support guide 34 so as to be immovable relative to it. In other words, the head unit 70 is rotatably connected to the housing 20 with the front-rear direction as the axial direction. A pair of upper and lower stoppers 22 fixed to the front end of the housing 20 abut against the holder plate 73, thereby holding the head unit 70 in place.

[0042] The main plate 74 is made of a metal plate and is formed into a generally elongated plate shape with its thickness in the left-right direction and extending in the front-rear direction. As described above, the rear portion of the main plate 74 is disposed between the upper portions of the pair of holder plates 73 and is fastened and fixed to the holder plates 73 by a pair of front and rear bolts BL2. When the main plate 74 is fixed to the blade holder 72, the main plate 74 is disposed adjacent to the upper side of the blade 60, and the front portion of the main plate 74 protrudes forward beyond the blade holder 72.

[0043] (Regarding the support head portion 75) As shown in Figures 1 to 6, the support head portion 75 is disposed in front of the blade holder 72 at a distance. The support head portion 75 has a pair of left and right head plates 76. The head plates 76 are made of metal plate material and are formed into a substantially rectangular plate shape with the left-right direction as the plate thickness direction and the up-down direction as the longitudinal direction. The pair of head plates 76 are disposed opposite each other in the left-right direction, and the front portion of the main plate 74 is disposed between the upper end portions of the pair of head plates 76. The pair of head plates 76 are fastened and fixed to each other by a pair of front and rear bolts BL2, sandwiching the main plate 74 from the outside in the left-right direction. The lower end portions of the pair of head plates 76 are fastened and fixed to each other by a bolt BL1.

[0044] As a result, an inlet 70A is formed in the head 70 between the blade holder 72 and the support head 75, and the inlet 70A is formed in a concave shape that is open downward when viewed from the right. The inlet 70A is configured as a receiving opening for receiving the first ceiling material 90 or the second ceiling material 92 into the head 70 when the first ceiling material 90 or the second ceiling material 92 is set on the support head 75.

[0045] A plurality of (four in this embodiment) support recesses 76A are formed in the rear end of the head plate 76 below the main plate 74. Each support recess 76A is cut out in a concave shape that opens to the rear and penetrates in the left-right direction. The support recesses 76A are arranged at predetermined intervals in the up-down direction. As a result, three support protrusions 76B are formed in the head plate 76 between the support recesses 76A. The rear ends of the support protrusions 76B form bottom wall head support portions 76C, and the front ends of the support recesses 76A form side wall head support portions 76D.

[0046] (Regarding the support adapter 78) The support adapter 78 is formed in a generally rectangular plate shape with its thickness direction in the left-right direction and its length direction in the up-down direction. The support adapter 78 is disposed adjacent to the right side of the support head unit 75 and is attached to the support head unit 75 by a connecting mechanism 80 so as to be movable in the up-down direction. Specifically, the support adapter 78 is configured to be movable between a first position (the position shown in FIGS. 1 and 2) and a second position (the position shown in FIG. 3) that is moved downward from the first position. That is, when the head unit 70 is in the first state, the support adapter 78 is disposed in the first position, and when the head unit 70 is in the second state, the support adapter 78 is disposed in the second position.

[0047] The rear end of the support adapter 78 is located forward of the side wall head support portion 76D of the support head portion 75. Four adapter support pieces 78A are formed at the rear end of the support adapter 78 and protrude rearward. The adapter support pieces 78A are formed in a generally rectangular plate shape and protrude rearward from the support adapter 78. The four adapter support pieces 78A are arranged vertically at intervals corresponding to the support recesses 76A of the support head portion 75. The width dimension (vertical dimension) of the adapter support pieces 78A is set slightly smaller than the width dimension of the support recesses 76A. The rear ends of the adapter support pieces 78A form side wall adapter support portions 78B.

[0048] When the support adapter 78 is in the first position, the adapter support piece 78A is positioned to cover the front end of the support recess 76A when viewed from the right side, and the sidewall adapter support part 78B is positioned in front of the sidewall head support part 76D (see FIG. 2). On the other hand, when the support adapter 78 is in the second position, the sidewall adapter support part 78B is positioned to overlap the support protrusion 76B when viewed from the right side. In other words, the sidewall adapter support part 78B is positioned downwardly relative to the sidewall head support part 76D (support recess 76A), so that the support recess 76A and the adapter support piece 78A are aligned alternately in the vertical direction.

[0049] When cutting the first ceiling material 90, the first ceiling material 90 is set on the head unit 70 in the first state. Specifically, the side wall 90B of the first ceiling material 90 is inserted into the support recess 76A from the rear, the bottom wall 90A of the first ceiling material 90 is supported from the front by the bottom wall head support unit 76C, and the tip of the side wall 90B of the first ceiling material 90 is supported from the front by the side wall adapter support unit 78B. When cutting the second ceiling material 92, the second ceiling material 92 is set on the head unit 70 in the second state. Specifically, the side wall 92B of the second light-weight material 92 is inserted into the support recess 76A from the rear side, the bottom wall 92A of the second light-weight material 92 is supported from the front side by the bottom wall head support portion 76C, and the tip of the side wall 92B of the second light-weight material 92 is supported from the front side by the side wall head support portion 76D.

[0050] That is, the head unit 70 supports the first ceiling material 90 (second ceiling material 92) at two different positions in the front-to-rear direction. Here, the position of the head unit 70 that supports the bottom wall 90A (bottom wall 92A) of the first ceiling material 90 (second ceiling material 92) is defined as a first support position P1, and the position that supports the side wall 90B (side wall 92B) of the first ceiling material 90 (second ceiling material 92) is defined as a second support position P2. The distance L between the first support position P1 and the second support position P2 in the front-to-rear direction is set to change between the first and second states of the head unit 70. Specifically, when the head unit 70 switches from the first state to the second state, the second support position P2 is shifted forward, and the distance L becomes longer.

[0051] As shown in FIGS. 3 to 6 , the connecting mechanism 80 includes a connecting pin 81, a lock shaft 82, and a moderation mechanism 86. The connecting pin 81 is formed in a generally cylindrical shape with its axis extending in the left-right direction and is attached to the support head 75. The right end of the connecting pin 81 protrudes to the right of the support head 75, and an upper corner of the front end of the support adapter 78 is connected to the right end of the connecting pin 81 so as to be relatively movable in the up-down direction. Specifically, the support adapter 78 is formed with an elongated hole 78C whose longitudinal direction is the up-down direction, and the right end of the connecting pin 81 is inserted into the elongated hole 78C so as to be relatively movable. When the support adapter 78 is in a first position, the connecting pin 81 is positioned at the lower end of the elongated hole 78C, and when the support adapter 78 is in a second position, the connecting pin 81 is positioned at the upper end of the elongated hole 78C.

[0052] The lock shaft 82 is formed in a generally cylindrical shape with its axial direction extending in the left-right direction, and is connected to the support head portion 75 and the support adapter 78 below the connecting pin 81 so as to be movable in the left-right direction. Specifically, the lock shaft 82 is connected to the head portion 75 and the support adapter 78 so as to be movable between a locked position (the position shown in FIG. 6A) and an unlocked position (the position shown in FIG. 6B) moved to the right from the locked position. Below, the lock shaft 82 will be described when placed in the locked position.

[0053] An elongated hole 78D with its longitudinal direction extending in the vertical direction is formed in the lower corner of the front end of the support adapter 78, and the right end of the lock shaft 82 is inserted through the elongated hole 78D so as to be relatively movable. Specifically, when the support adapter 78 is in the first position, the lock shaft 82 is disposed at the lower end of the elongated hole 78D, and when the support adapter 78 is in the second position, the lock shaft 82 is disposed at the upper end of the elongated hole 78D. A restricting protrusion 78E (see FIG. 3 ) that protrudes rearward is formed at the middle portion in the vertical direction on the front inner periphery of the elongated hole 78D. As a result, when the support adapter 78 is in the first position (second position), the outer periphery of the lock shaft 82 engages with the restricting protrusion 78E, restricting downward (upward) movement of the support adapter 78 in the first position (second position).

[0054] As shown in FIGS. 6A and 6B , a recess 82A is formed in the outer periphery of the right end portion of the lock shaft 82. The recess 82A is a groove that opens forward and penetrates vertically. The recess 82A is deeper than the protrusion of the restricting protrusion 78E. The recess 82A is located to the left of the elongated hole 78D of the support adapter 78. This maintains the engagement between the outer periphery of the lock shaft 82 and the restricting protrusion 78E when the lock shaft 82 is in the locked position. On the other hand, when the lock shaft 82 is in the unlocked position, the recess 82A is positioned within the elongated hole 78D of the support adapter 78, and the recess 82A disengages the outer periphery of the lock shaft 82 from the restricting protrusion 78E. This allows the support adapter 78 to move between the first position and the second position by moving the lock shaft 82 to the unlocked position.

[0055] The left end of the lock shaft 82 protrudes to the left from the support head portion 75, and a lock button 83 is provided at this left end. A biasing spring 84 is fitted onto the left end of the lock shaft 82, and is configured as a compression coil spring. The biasing spring 84 is disposed between the support head portion 75 and the lock button 83 and biases the lock button 83 to the left. As a result, the biasing force of the biasing spring 84 holds the lock shaft 82 in the locked position. A retaining ring 85 is provided at the right end of the lock shaft 82, and the retaining ring 85 limits movement of the lock shaft 82 to the left when in the locked position.

[0056] As shown in FIGS. 3 to 5 , the detent mechanism 86 includes a detent spring 87 and a detent protrusion 76G. A pair of front and rear adapter-side through-holes 78F for arranging the detent spring 87 are formed through the support adapter 78. The adapter-side through-hole 78F is formed in a rectangular shape with its longitudinal direction extending vertically. A head-side through-hole 76E for arranging the detent spring 87 is also formed through the right head plate 76. The head-side through-hole 76E is formed in a rectangular shape with its longitudinal direction extending vertically. When viewed from the left and right, the pair of adapter-side through-holes 78F are positioned so as to overlap the lower portions of the head-side through-holes 76E. A pair of upper and lower notches 76F are formed through the front inner periphery of the head-side through-hole 76E. The notches 76F are formed in a concave shape that opens to the rear. The portion of the head plate 76 between the pair of notches 76F serves as the detent protrusion 76G.

[0057] The detent spring 87 is configured as a leaf spring. When viewed from below, the detent spring 87 is bent into a generally U-shape that opens to the left (see FIG. 4 ). Specifically, the detent spring 87 includes a right wall 87A, a front wall 87B extending leftward from the front end of the right wall 87A, and a rear wall 87C extending leftward from the rear end of the right wall 87A. The front wall 87B and the rear wall 87C of the detent spring 87 are configured to be elastically deformable in the front-to-rear direction. The front wall 87B and the rear wall 87C of the detent spring 87 are inserted from the right side into the adapter-side insertion hole 78F of the support adapter 78 and the head-side insertion hole 76E of the head plate 76, and the right wall 87A of the detent spring 87 is fastened to the support adapter 78 by a fixing bolt SC3.

[0058] The tip of the rear wall 87C of the moderation spring 87 is bent rearward and abuts against the edge of the head-side insertion hole 76E of the head plate 76. The rear wall 87C of the moderation spring 87 also abuts against the inner periphery of the head-side insertion hole 76E of the head plate 76, urging the head plate 76 rearward.

[0059] An engaging protrusion 87D is formed at the tip of the front wall 87B of the detent spring 87. When viewed from the right side, the engaging protrusion 87D is formed in a generally inverted C-shape that opens toward the rear and protrudes forward from the front wall 87B. When the support adapter 78 is in the first position, the engaging protrusion 87D is positioned within the upper notch 76F of the head plate 76. When the support adapter 78 is in the second position, the engaging protrusion 87D is positioned within the lower notch 76F. Therefore, when the support adapter 78 moves between the first and second positions, the front wall 87B elastically deforms rearward, causing the engaging protrusion 87D to ride over the detent protrusion 76G of the head plate 76, thereby providing a detent (click) feeling to the support adapter 78. A handle 78G bent to the right is formed at the lower end of the support adapter 78, allowing an operator to grasp the handle 78G to move the support adapter 78 up and down.

[0060] (Regarding the controller 64) As shown in FIG. 1 , the controller 64 is housed 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 motor 40, and the lifter detection switch 58 are electrically connected to the controller 64. The controller 64 detects the initial position of the lifter 55 based on a detection signal from the lifter detection switch 58. The controller 64 also controls the drive of the motor 40 based on output signals from the trigger switch 32 and the lifter detection switch 58. When the controller 64 drives the motor 40 in the forward direction, the lifter 55 (blade 60) moves forward. On the other hand, when the controller 64 drives the motor 40 in the reverse direction, the lifter 55 (blade 60) moves rearward.

[0061] Furthermore, when the trigger 30 is released and the trigger switch 32 switches from on to off while the motor 40 is rotating forward, the controller 64 drives the motor 40 in the reverse direction. The controller 64 has a current detection unit that detects the current value of the motor 40. The controller 64 detects the stop position of the lifter 55 (blade 60) based on the detection signal from the current detection unit. Specifically, if the current value of the motor 40 exceeds a predetermined value while the motor 40 is rotating forward, the controller 64 detects the start of cutting the first plasterwork material 90 (first plasterwork material 90). If the current value of the motor 40 falls below the current value in a no-load state after detecting the start of cutting, the controller 64 determines that cutting the first plasterwork material 90 (first plasterwork material 90) is complete and detects the stop position of the lifter 55 (blade 60). Furthermore, when the controller 64 detects the stop position of the lifter 55 (blade 60), it stops driving the motor 40, and drives the motor 40 in the reverse direction after a predetermined time has elapsed or after detecting an operation on the trigger 30.

[0062] The method for stopping the motor 40 when the blade 60 reaches the stop position is not limited to the above. For example, the shearing tool 10 may be provided with a button for selecting the first plasterwork material 90 or the second plasterwork material 92 to be set in the head unit 70, and the controller 64 may detect the plasterwork material to be cut according to the selected button. The controller 64 may also detect the rotation speed of the drive shaft 40A of the motor 40 and the position of the blade 60 based on the detected rotation speed. The controller 64 may then stop the motor 40 when it detects that the blade 60 has reached the stop position corresponding to the plasterwork material selected by the button.

[0063] (Operation and Effect) Next, the operation and effect of the shearing tool 10 of this embodiment will be described.

[0064] When the shearing tool 10 configured as described above is used to cut the first ceiling material 90, the first ceiling material 90 is set on the head 70 in the first state. Specifically, the support adapter 78 is placed in the first position, and the adapter support piece 78A of the support adapter 78 blocks the front end of the support recess 76A of the support head 75 from the right side. This positions the sidewall adapter support portion 78B of the support adapter 78 in front of the sidewall head support portion 76D of the support head 75 so as to be able to support the sidewall 90B of the first ceiling material 90. The first ceiling material 90 is then inserted from below into the inlet portion 70A of the head 70 and positioned behind the support head 75. The shearing tool 10 is then moved rearward relative to the first ceiling material 90, and the first ceiling material 90 is set on the support head 75. As a result, the bottom wall head support portion 76C of the support head portion 75 supports the bottom wall 90A of the first light-weight material 90 from the front side, and the side wall adapter support portion 78B of the support adapter 78 supports the side wall 90B of the first light-weight material 90 from the front side.

[0065] On the other hand, when the shearing tool 10 is used to cut the second light-weight material 92, the head unit 70 is switched from the first state to the second state, and the second light-weight material 92 is placed on the head unit 70 in the second state. When switching the head unit 70 to the second state, the operator presses the lock button 83 to the right to move the lock shaft 82 from the locked position to the unlocked position. This positions the clearance groove 82A of the lock shaft 82 within the elongated hole 78D of the support adapter 78, allowing the support adapter 78 to move downward. In this state, the operator grasps the handle 78G of the support adapter 78 and moves the support adapter 78 downward to the second position. At this time, the engaging protrusion 87D of the detent spring 87 overcomes the detent protrusion 76G of the head plate 76, providing a detent feeling to the support adapter 78. Then, by releasing the pressure on the lock button 83, the lock shaft 82 returns to the locked position due to the biasing force of the biasing spring 84. As a result, the head unit 70 is switched to the second state.

[0066] When the support adapter 78 is in the second position, the sidewall adapter support portion 78B of the support adapter 78 is positioned below the support recess 76A of the support head 75 and is retracted to a position where it does not support the second ceiling material 92. The second ceiling material 92 is then inserted from below into the inlet portion 70A of the head 70 and positioned behind the support head 75. The shearing tool 10 is then moved rearward relative to the second ceiling material 92 to set the second ceiling material 92 on the support head 75. As a result, the bottom wall head support portion 76C of the support head 75 supports the bottom wall 92A of the second ceiling material 92 from the front, and the sidewall head support portion 76D of the support head 75 supports the side wall 92B of the second ceiling material 92 from the front.

[0067] That is, when the head unit 70 is in the first state, the first ceiling material 90 is supported from the front by the support head unit 75 and the support adapter 78, and when the head unit 70 is in the second state, the second ceiling material 92 is supported from the front only by the support head unit 75. When the head unit 70 is switched from the first state to the second state, the second support position P2 of the head unit 70 is moved forward, and the distance L between the first support position P1 and the second support position P2 becomes longer.

[0068] When the shearing tool 10 cuts the first plasterwork material 90 (second plasterwork material 92), the trigger 30 is operated and the trigger switch 32 is turned on, causing the motor 40 to rotate forward under the control of the controller 64. This activates the feed screw mechanism 50, causing the lifter 55 to move the blade 60 forward (the forward path, i.e., one side in the front-to-rear direction). As a result, the blade 60 approaches the first plasterwork material 90 (second plasterwork material 92), and the first plasterwork material 90 (second plasterwork material 92) supported by the head unit 70 is sandwiched between the blade 60 and the head unit 70, thereby cutting the first plasterwork material 90 (second plasterwork material 92). When the controller 64 detects the stop position of the lifter 55 (blade 60) based on the detection signal from the current detector, it stops the forward rotation of the motor 40. This completes the cutting process for the first light-weight ceiling material 90 (second light-weight ceiling material 92).

[0069] After the cutting process is completed, the driving of the motor 40 is automatically stopped, and when the trigger switch 32 is turned on again, the motor 40 rotates in the reverse direction under the control of the controller 64, the feed screw mechanism 50 is activated again, and the blade 60 moves rearward (the return path, the other side in the front-to-rear direction) by the lifter 55 of the feed screw mechanism 50. When the controller 64 detects the initial position of the lifter 55 based on the detection signal of the lifter detection switch 58, the driving of the motor 40 is stopped by the controller 64.

[0070] As described above, in the shearing tool 10, the head unit 70 includes a support head unit 75 and a support adapter 78. The head unit 70 is switchable between a first state in which it supports a first ceiling material 90 and a second state in which it supports a second ceiling material 92 having a different height from the first ceiling material 90. Specifically, the head unit 70 supports the bottom wall 90A (bottom wall 92A) of the first ceiling material 90 (second ceiling material 92) at a first support position P1 and supports the side wall 90B (side wall 92B) of the first ceiling material 90 (second ceiling material 92) at a second support position P2 located forward of the first support position P1. The head unit 70 can change the distance L between the first support position P1 and the second support position P2 in the front-to-rear direction depending on the ceiling material being supported by the head unit 70. Specifically, when the head unit 70 is switched from the first state to the second state, the second support position P2 is shifted forward, increasing the distance L. Therefore, with the shearing tool 10 of this embodiment, even when cutting the first and second ceiling materials 90 and 92, which have different heights, both ceiling materials can be supported at two different positions in the front-to-rear direction. As a result, for example, there is no need to prepare multiple work machines to cut ceiling materials of different heights. As a result, the operability of the shearing tool 10 can be improved.

[0071] The support adapter 78 is attached to the support head 75 so as to be movable in the vertical direction. The distance L between the first support position P1 and the second support position P2 on the head 70 is changed by moving the support adapter 78 to the first position or the second position. Specifically, as described above, when the support adapter 78 is in the first position, the sidewall adapter support portion 78B of the support adapter 78 is positioned so as to support the sidewall 90B of the first ceiling material 90. As a result, the bottom wall head support portion 76C of the support head 75 supports the bottom wall 90A of the first ceiling material 90 at the first support position P1, and the sidewall adapter support portion 78B of the support adapter 78 supports the sidewall 90B of the first ceiling material 90 at the second support position P2. Meanwhile, when the support adapter 78 is in the second position, the support adapter 78 is retracted to a position where it does not support the second ceiling material 92. As a result, the bottom wall head support portion 76C of the support head portion 75 supports the bottom wall 92A of the second ceiling material 92, and the side wall head support portion 76D of the support head portion 75 supports the side wall 92B of the second ceiling material 92 at the second support position P2. This makes it possible to change the front-to-rear position of the second support position P2 of the head portion 70 with a simple configuration, thereby switching the head portion 70 between the first state and the second state.

[0072] The controller 64 also has a current detection unit that detects the current value of the motor 40, and based on the detection signal from the current detection unit, detects the completion of cutting by the blade 60 and stops the motor 40. That is, even when cutting the first and second ceiling materials 90 and 92, which have different heights, the motor 40 can be automatically stopped when cutting is complete. After the motor 40 automatically stops, the motor 40 can be rotated in the reverse direction to return the blade 60 to its initial position. This further improves the operability of the shearing tool 10.

[0073] (Regarding Modification 1 of Head Unit 70) Next, Modification 1 of the head unit 70 will be described using Figures 7(A) and (B). The head unit 70 of Modification 1 is configured similarly to the head unit 70 of the present embodiment, except for the following points. Note that in Figures 7(A) and (B), the same components as those in the head unit 70 of the present embodiment are denoted by the same reference numerals.

[0074] As shown in this figure, in Modification 1 of the head unit 70, the lock button 83 and the biasing spring 84 are omitted from the lock shaft 82 of the connecting mechanism 80, and the lock shaft 82 is connected to the support head unit 75 so as to be immovable in the left-right direction but rotatable about its axis. A knob 88 is fixed to the right end of the lock shaft 82 and protrudes from the lock shaft 82 on both sides in the front-to-rear direction. The relief groove 82A of the lock shaft 82 is disposed within the elongated hole 78D of the support adapter 78. Furthermore, in the second state of the head unit 70, the relief groove 82A is disposed in a position that opens upward. As a result, the outer periphery of the lock shaft 82 engages with the restricting protrusion 78E of the support adapter 78, restricting downward movement of the support adapter 78 in the second position. On the other hand, when viewed from the right side, rotating the knob 88 90 degrees clockwise positions the relief groove 82A facing the restricting protrusion 78E in the vertical direction, allowing the support adapter 78 to move upward from the second position. Then, by rotating the knob 88 90 degrees clockwise after moving the support adapter 78 to the first position, the outer periphery of the lock shaft 82 engages with the restricting protrusion 78E of the support adapter 78, restricting downward movement of the support adapter 78 from the first position. A retaining ring 85 is provided on the left end of the lock shaft 82, and an elastic O-ring 89 is provided in an elastically deformed state between the retaining ring 85 and the support head 75. The O-ring 89 thus prevents the lock shaft 82 from spinning freely.

[0075] Furthermore, in the first modified example of the head unit 70, the head unit 70 can be switched between a first state in which it supports the first ceiling material 90 and a second state in which it supports the second ceiling material 92, which has a different height dimension from the first ceiling material 90. Specifically, when the head unit 70 is switched from the first state to the second state, the second support position P2 on the head unit 70 is shifted forward, and the distance between the first support position P1 and the second support position P2 becomes longer. Therefore, in the first modified example of the head unit 70, as in the present embodiment, the operability of the shearing tool 10 can be improved.

[0076] Furthermore, in the first modification of the head unit 70, the movement of the support adapter 78 between the first position and the second support position P2 is permitted by rotating the lock shaft 82. In other words, there is no need to move the lock shaft 82 in the left-right direction. This can contribute to reducing the size of the head unit 70 in the left-right direction.

[0077] (Regarding Modification 2 of Head Unit 70) Next, Modification 2 of the head unit 70 will be described using Figures 8(A) and (B) and Figure 9. The head unit 70 of Modification 2 is configured similarly to the head unit 70 of the present embodiment, except for the following points. Note that in Figures 8(A) and (B) and Figure 9, the same components as those in the head unit 70 of the present embodiment are denoted by the same reference numerals.

[0078] As shown in these figures, in the second modification of the head unit 70, the connecting mechanism 80 is omitted from the head unit 70. Furthermore, in the second modification, instead of the support adapter 78, a support adapter 100 serving as a support position change member is detachably attached to the support head unit 75 by a magnet 102 (see FIGS. 8A and 9 ). The support adapter 100 is formed in a generally rectangular plate shape with a thickness extending in the left-right direction and extending vertically. The rear end of the support adapter 100 serves as a sidewall adapter support portion 100A for supporting the sidewall 90B of the first ceiling member 90. The magnet 102 is formed in a generally elongated plate shape with a thickness extending in the left-right direction and extending vertically. The magnet 102 is embedded in the support adapter 100, and the left surface of the magnet 102 is exposed from the left surface of the support adapter 100. Four positioning protrusions 100B are formed at the rear end of the left surface of the support adapter 100. The positioning protrusion 100B is formed in a rectangular shape when viewed from the left side, and protrudes leftward from the supporting adapter 100.

[0079] As shown in FIG. 8A , when the head unit 70 is in the first state, the support adapter 100 is attached to the right side surface of the support head unit 75 by the magnetic force of the magnet 102. In this state, the four positioning protrusions 100B are fitted into the front ends of the support recesses 76A in the support head unit 75, determining the position of the support adapter 100 relative to the support head unit 75. The sidewall adapter support portion 100A is positioned in front of the sidewall head support portion 76D of the support head unit 75 so as to be able to support the sidewall 90B of the first ceiling member 90. Meanwhile, as shown in FIG. 8B , when the head unit 70 is in the second state, the support adapter 100 is removed from the support head unit 75. This exposes the sidewall head support portion 76D of the support head unit 75 so as to be able to support the sidewall 92B of the second ceiling member 92. That is, in the second modification, the head unit 70 switches between the first state and the second state depending on whether the support adapter 100 is attached to or detached from the support head unit 75, and the distance L between the first support position P1 and the second support position P2 of the head unit 70 is changed. Therefore, in the second modification of the head unit 70, as in the present embodiment, the operability of the shearing tool 10 can be improved.

[0080] In the second modification, as described above, the head unit 70 switches between the first state and the second state depending on whether the support adapter 100 is attached to the support head unit 75 or detached from the support head unit 75. Therefore, in this invention, "the distance between the first support position and the second support position in a predetermined direction is changed depending on the attachment state of the support position change member to the head unit" also includes the case where the distance L between the first support position P1 and the second support position P2 of the head unit 70 is changed depending on the attachment state of the support head unit 75 of the support adapter 100.

[0081] (Regarding Modification 3 of Head Unit 70) Next, Modification 3 of the head unit 70 will be described using Figures 10(A) and (B) and Figures 11(A) to (C). The head unit 70 of Modification 3 is configured similarly to the head unit 70 of the present embodiment, except for the points described below. Note that in Figures 10(A) and (B) and Figures 11(A) to (C), the same components as those in the head unit 70 of the present embodiment are denoted by the same reference numerals.

[0082] 10A , in the head unit 70 of the third modified example, similar to the second modified example, the coupling mechanism 80 is omitted from the support head unit 75. Also, in the third modified example, instead of the support adapter 78, a support adapter 200 as a support position changing member is detachably attached to the support head unit 75 by a pair of attachment mechanisms 210.

[0083] The support adapter 200 is formed in the shape of a generally rectangular plate with its thickness extending in the left-right direction and its length extending in the up-down direction. The rear end of the support adapter 200 serves as a side wall adapter support portion 200A for supporting the side wall 90B of the first ceiling material 90. Four positioning protrusions 200B are formed at the rear end of the left surface of the support adapter 200. The positioning protrusions 200B are formed in a rectangular shape when viewed from the left side, and protrude to the left from the support adapter 200.

[0084] As shown in FIG. 11A , the mounting mechanism 210 includes a mounting shaft 212 and a stopper plate 216. The mounting shaft 212 is formed in a generally stepped cylindrical shape with its axis extending in the left-right direction, and an enlarged head 212A is formed at the right end of the mounting shaft 212. The mounting shaft 212 passes through a sleeve 220 provided in the support head 75 and a mounting hole 200C formed in the support adapter 200. The right end of the mounting shaft 212 protrudes to the right from the head 70, and the left end of the mounting shaft 212 protrudes to the left from the support head 75. A slit 212B for accommodating the stopper plate 216 is formed in the vertical center of the left end of the mounting shaft 212. The slit 212B is formed in a groove-like shape with its width extending in the up-down direction and open to the left, and penetrates in the front-to-rear direction. A pin 214 having an axial direction extending in the vertical direction is provided in the slit 212B, and both ends of the pin 214 are supported by the mounting shaft 212.

[0085] The stopper plate 216 is formed in a generally rectangular plate shape with its thickness extending vertically and its length extending longitudinally. The rear end of the stopper plate 216 forms a gripping portion 216A that is gripped by an operator. A slide hole 216B is formed through the front of the stopper plate 216 in the center of the left-right direction. The slide hole 216B is an elongated hole extending in the front-rear direction (the longitudinal direction of the stopper plate 216). The stopper plate 216 is inserted into the slit 212B of the mounting shaft 212 so as to be relatively movably fitted thereto, and the pin 214 is inserted into the slide hole 216B so as to be relatively movably fitted thereto. Specifically, the pin 214 is positioned within the front end of the slide hole 216B, and the rear of the stopper plate 216 protrudes rearward from the mounting shaft 212 and is located to the left of a washer 222 provided on the left side of the sleeve 220. This restricts rightward movement of the mounting shaft 212. The width dimension (left-right dimension) of the stopper plate 216 is set smaller than the inner diameter of the sleeve 220. The front-rear end portions of the slide hole 216B are enlarged more than the central portion, and the pin 214 engages with the recessed portions.

[0086] A retaining spring 224 is fitted onto the right end portion of the mounting shaft 212. The retaining spring 224 is configured as a compression coil spring, and urges the head 212A of the mounting shaft 212 to the right, and urges the support adapter 200 to the left via the washer 222. As a result, the right-side urging force of the retaining spring 224 is applied to the support head portion 75 via the mounting shaft 212, the stopper plate 216, and the left-side washer 222. As a result, the support adapter 200 is sandwiched in the left-right direction between the support head portion 75 and the mounting shaft 212 and fixed to the support head portion 75.

[0087] To release the attachment of the support adapter 200 to the support head 75 by the attachment mechanism 210, the worker presses the attachment shaft 212 leftward to move the attachment shaft 212 to the left against the biasing force of the retaining spring 224. Next, as viewed from below, the stopper plate 216 is rotated 90 degrees counterclockwise around the axis of the pin 214 to align the axial direction of the attachment shaft 212 with the longitudinal direction of the stopper plate 216 (see FIG. 11(B)). This releases the restriction on rightward movement of the attachment mechanism 210 imposed by the stopper plate 216. Then, the worker removes the attachment mechanism 210 from the support adapter 200 and the support head 75, thereby releasing the attachment of the support adapter 200 to the support head 75 (see FIG. 11(C)).

[0088] As shown in FIG. 10A , in the first state of the head unit 70, the mounting mechanism 210 mounts the support adapter 200 to the right side of the support head unit 75. In this state, the four positioning protrusions 200B are fitted into the front ends of the support recesses 76A in the support head unit 75, determining the position of the support adapter 200 relative to the support head unit 75. Furthermore, the sidewall adapter support unit 200A is positioned in front of the sidewall head support unit 76D of the support head unit 75 so as to be able to support the sidewall 90B of the first ceiling material 90. Meanwhile, as shown in FIG. 10B , in the second state of the head unit 70, the mounting mechanism 210 releases the support adapter 200 from its mounting position, and the support adapter 200 is removed from the support head unit 75. This exposes the sidewall head support unit 76D of the head unit 70 so as to be able to support the sidewall 92B of the second ceiling material 92. That is, in the third modification, similar to the second modification, the head unit 70 switches between the first state and the second state depending on the state of attachment or detachment of the support adapter 200 to the support head unit 75, and the distance L between the first support position P1 and the second support position P2 of the head unit 70 is changed. Therefore, in the third modification of the head unit 70, similar to the present embodiment, the operability of the shearing tool 10 can be improved.

[0089] (Regarding Variation 4 of Head Unit 70) Next, Variation 4 of the head unit 70 will be described using Figures 12(A) and (B) and Figures 13(A) and (B). The head unit 70 of Variation 4 is configured similarly to the head unit 70 of this embodiment, except for the points described below. Note that in Figures 12(A) and (B) and Figures 13(A) and (B), the same components as those in the head unit 70 of this embodiment are denoted by the same reference numerals.

[0090] As shown in these figures, in the fourth modification of the head unit 70, a support adapter 300 is provided as a support position changing member on the support head unit 75 instead of the support adapter 78. Also, in the fourth modification, the head unit 70 has a connecting mechanism 310 instead of the connecting mechanism 80, and the support adapter 300 is connected to the support head unit 75 by the connecting mechanism 310 so as to be rotatable about an axial direction that is the up-down direction.

[0091] As shown in Figures 12(A) and (B), the support adapter 300 is formed in a generally rectangular block shape with its thickness extending in the left-right direction and its length extending in the up-down direction. The rear end of the support adapter 300 forms a sidewall adapter support portion 300A for supporting the sidewall 90B of the first ceiling material 90. A pair of upper and lower hinge portions 300B is provided at the front end of the support adapter 300. The hinge portion 300B is formed in a cylindrical shape with its axis extending in the up-down direction and protruding forward from the support adapter 300. An engagement recess 300C is formed between the pair of hinge portions 300B at the front end of the support adapter 300. When viewed from the right side, the engagement recess 300C is formed in a recessed shape that opens to the front and penetrates in the left-right direction. Four positioning protrusions 300D are formed at the rear end of the left surface of the support adapter 300. The positioning protrusion 300D is formed in a rectangular shape when viewed from the left side, and protrudes leftward from the support adapter 300.

[0092] The connecting mechanism 310 is configured to include a base 312, a support shaft 314, and a pair of adapter holders 316. The base 312 is provided in the vertical middle of the right head plate 76 and protrudes to the right from the head plate 76. The right side surface of the base 312 is formed in a stepped shape when viewed from below, and the front portion of the right side surface of the base 312 is located to the left of the rear portion of the right side surface of the base 312. The hinge portions 300B of the support adapter 300 are located on both vertical sides of the rear portion of the base 312.

[0093] The support shaft 314 is formed in a generally cylindrical shape with its axial direction extending vertically. An enlarged-diameter head 314A is formed at the lower end of the support shaft 314. The support shaft 314 is rotatably supported by the base 312 and is inserted into the hinge 300B so as to be relatively rotatable, thereby rotatably supporting the support adapter 300. In other words, the support adapter 300 is rotatably connected to the support head 75 with its axial direction extending vertically.

[0094] The pair of adapter holders 316 are made of an elastic material such as rubber and are formed into a generally rectangular parallelepiped shape with a thickness in the front-to-rear direction and extending in the up-down direction. One adapter holder 316 is attached to the support head 75 on the front side of the vertically middle portion of the base 312 and protrudes to the right from the support head 75. The other adapter holder 316 is provided at the front of the base 312 and protrudes to the right from the base 312.

[0095] When the support adapter 300 is in the first position, it is positioned adjacent to the right side of the support head 75, protruding rearward from the base 312. When the support adapter 300 is in the first position, the four positioning protrusions 300D are fitted into the front ends of the support recesses 76A of the support head 75. Furthermore, the rear adapter holder 316 is positioned within the engagement recess 300C of the support adapter 300, and both vertical ends of the adapter holder 316 are pressed (compressed) inward in the vertical direction by the inner circumferential surfaces of the engagement recesses 300C. This prevents the support adapter 300 from moving due to the pressing force from the adapter holder 316 (frictional force with the adapter holder 316), holding the support adapter 300 in the first position. The sidewall adapter support 300A is positioned in front of the sidewall head support 76D of the support head 75, allowing it to support the sidewall 90B of the first ceiling material 90.

[0096] On the other hand, when viewed from below, rotating the support adapter 78 180 degrees clockwise places the support adapter 300 in the second position (see FIGS. 13A and 13B). In the second position, the support adapter 300 protrudes forward from the rear of the base 312 and is positioned adjacent to the right side of the front of the base 312. In this position, the entire support adapter 300 is positioned in front of the support recess 76A of the support head 75, exposing the sidewall head support 76D of the support head 75 so that it can support the sidewall 92B of the second ceiling material 92. In this position, the front adapter holder 316 is positioned within the engagement recess 300C of the support adapter 300, and both vertical ends of the adapter holder 316 are pressed (compressed) inward in the vertical direction by the inner circumferential surface of the engagement recess 300C. As a result, the movement of the supporting adapter 300 is suppressed by the pressing force from the adapter holding portion 316 (frictional force with the adapter holding portion 316), and the supporting adapter 300 is held in the second position.

[0097] As described above, the head unit 70 switches between the first state and the second state depending on the attachment state of the support adapter 300 to the support head unit 75, and the distance L between the first support position P1 and the second support position P2 of the head unit 70 is changed. Therefore, in the fourth modification of the head unit 70, as in the present embodiment, the operability of the shearing tool 10 can be improved. Furthermore, in the fourth modification, the load applied to the support adapter 300 by the positioning protrusion 300D during cutting is transmitted to the support head unit 75 via the side wall head support portion 76D, thereby suppressing deformation and damage to the base portion 312 supporting the support adapter 300, the support shaft 314, etc.

[0098] (Regarding Modification 5 of Head Unit 70) Next, Modification 5 of the head unit 70 will be described using Figures 14(A) and (B). The head unit 70 of Modification 5 is configured similarly to the head unit 70 of the present embodiment, except for the following points. Note that in Figures 14(A) and (B), the same components as those in the head unit 70 of the present embodiment are denoted by the same reference numerals.

[0099] As shown in this figure, in the fifth modification of the head unit 70, a support adapter 400 is provided on the support head unit 75 as a support position changing member instead of the support adapter 78. Also, in the fifth modification, the head unit 70 has the attachment mechanism 210 used in the third modification instead of the connecting mechanism 80, and the support adapter 400 is detachably attached to the support head unit 75 by the attachment mechanism 210. Also, in the fifth modification, the support adapter 400 is configured to be attached to the support head unit 75 at two different positions in the front-to-rear direction. That is, the support adapter 400 has four attachment holes 400C for attaching the attachment mechanism 210.

[0100] In the support head 75 of Modification 5, one support recess 76A is formed at the rear end of the support head 75, and the width dimension (vertical dimension) of the support recess 76A is larger than that of the present embodiment. Furthermore, the support protrusion 76B is omitted from the support head 75. That is, the bottom wall head support portion 76C is omitted from the support head 75. The front end of the support recess 76A serves as a sidewall head support portion 76D. In Modification 5, the sidewall head support portion 76D supports the sidewall 90B of the first ceiling member 90 and the sidewall 92B of the second ceiling member 92 from the front. That is, in Modification 5, the second support position P2 of the head 70 is set to remain unchanged.

[0101] The support adapter 400 is formed in a generally rectangular plate shape with its thickness in the left-right direction and its length in the up-down direction, and is positioned adjacent to the right side of the support adapter 78. Three adapter support pieces 400A are formed at the rear end of the support adapter 400. The adapter support pieces 400A are formed in shapes corresponding to the support protrusions 76B omitted from the support head 75, and protrude rearward from the rear end of the support adapter 400. The rear ends of the adapter support pieces 400A form bottom wall adapter support parts 400B. In Variation 5, the bottom wall adapter support parts 400B support the bottom wall 90A of the first ceiling member 90 and the bottom wall 92A of the second ceiling member 92 from the front.

[0102] The position of the mounting mechanism 210 is set so that the support adapter 400 can be attached to the support head 75 at two different positions in the front-to-rear direction. Specifically, as shown in Figure 14(A), when the support adapter 400 is in a first position, the support adapter 400 is attached to the support head 75 so that the bottom wall adapter support part 400B is positioned adjacent to the front side of the bottom wall 90A of the first ceiling member 90. On the other hand, as shown in Figure 14(B), when the support adapter 400 is in a second position, the support adapter 400 is attached to the support head 75 so that the bottom wall adapter support part 400B is positioned adjacent to the front side of the bottom wall 92A of the second ceiling member 92.

[0103] That is, in Modification 5, when the head unit 70 is switched from the first state to the second state, the mounting position of the support adapter 400 is shifted rearward, and the position of the bottom wall adapter support portion 400B of the support adapter 400 is shifted rearward. As a result, when the head unit 70 is switched from the first state to the second state, the position of the first support position P1 on the head unit 70 is shifted rearward, and the distance L between the first support position P1 and the second support position P2 is increased. Therefore, in Modification 5 of the head unit 70, the head unit 70 can also be switched between a first state in which the head unit 70 supports the first ceiling material 90 and a second state in which the head unit 70 supports the second ceiling material 92, which has a height dimension different from that of the first ceiling material 90. As described above, in Modification 5 of the head unit 70, the operability of the shearing tool 10 can be improved, as in the present embodiment.

[0104] In Modification 5, the support adapter 400 is detachably attached to the support head 75 at two different positions in the front-to-rear direction. However, as in Modification 3, the support adapter 400 may be detachably attached to a single position in the front-to-rear direction. For example, as shown in FIG. 15 , the support adapter 400 may be detachably attached to the support head 75 at the second position. In this case, a support protrusion 76B may be formed on the support head 75, and the position of the bottom wall head support portion 76C on the support protrusion 76B may be moved forward compared to the present embodiment so that the bottom wall 90A of the first ceiling material 90 can be supported by the support head 75 when the support adapter 78 is removed. When the support adapter 78 is attached, the support head 75 and the support adapter 78 can support the second ceiling material 92.

[0105] (Regarding Modification 6 of Head Unit 70) Next, Modification 6 of the head unit 70 will be described using FIGS. 16 and 17. The head unit 70 of Modification 6 is configured similarly to the head unit 70 of the present embodiment, except for the following points. Note that in FIGS. 16 and 17, the same components as those of the head unit 70 of the present embodiment are denoted by the same reference numerals. FIG. 16(A) is a side view of Modification 6 in the first state, as seen from the left side; FIG. 16(B) is a cross-sectional view taken along line 16A-16A in FIG. 16(A); and FIG. 16(C) is an enlarged view of the portion circled by the dashed-dotted line in FIG. 16(B). FIG. 17(A) is a side view of Modification 6 in the second state, as seen from the left side; FIG. 17(B) is a cross-sectional view taken along line 17A-17A in FIG. 16(A); and FIG. 17(C) is an enlarged view of the portion circled by the dashed-dotted line in FIG. 16(B).

[0106] As shown in this figure, in the sixth variation of the head unit 70, a support adapter 500 is provided on the support head unit 75 as a support position change member instead of the support adapter 78. The support adapter 500 has three adapter support pieces 500A and three bottom wall adapter support portions 500B corresponding to the three support protrusions 76B. The bottom wall head support portion 76C also has a first inclined portion 76H and a second inclined portion 76J. The first inclined portion 76H and the second inclined portion 76J are configured as inclined surfaces inclined vertically. The first inclined portion 76H has a gentler inclination angle relative to the vertical direction than the second inclined portion 76J. The second inclined portion 76J is intended for chamfering and to prevent wear due to contact with the support adapter 500. The bottom wall adapter support portion 500B also has a protrusion 500C, which is provided with an inclined portion 500D. The protrusion 500C protrudes to the right from one end (rear end in the second state) of the bottom wall adapter support part 500B. The support adapter 500 is rotatably attached to the support head part 75 by bolt BL5. By rotating the support adapter 500 around bolt BL5, the state can be changed from the first state shown in FIG. 16 to the second state shown in FIG. 17. As shown in FIG. 17, in the second state, the protrusion 500C is located behind the bottom wall head support part 76C (first inclined part 76H), and the first inclined part 76H and the inclined part 500D abut or are very close to each other. In the second state, the bottom wall adapter support part 500B, including the protrusion 500C, is configured to support and process the plasterboard material. Specifically, in the second state, the rear surface of the bottom wall adapter support part 500B (including the rear surface of the protrusion 500C), which is parallel to the up-down and left-right directions, comes into surface contact with the side of the ceiling material, thereby supporting the ceiling material during cutting. Meanwhile, in the first state, the protrusion 500C, which was located behind the bottom wall head support part 76C, has moved to another location, and the bottom wall of the ceiling material 90 is supported by the bottom wall head support part 76C, which is part of the support head part 75, during processing.16, the formation of the first inclined portion 76H and the second inclined portion 76J makes the rear end of the bottom wall head support portion 76C convex backward, so in the first state the bottom of the ceiling material 90 is supported by line contact with the bottom wall head support portion 76C. When changing from the second state to the first state, the support for the bottom of the ceiling material 90 changes from surface contact to line contact, but because the ceiling material 90 is also supported in other places such as the support recess 76A, the stability of the ceiling material 90 is ensured when cutting.

[0107] In Modification 6, during cutting in the second state, the first inclined portion 76H and the inclined portion 500D come into contact or are very close to each other. Therefore, during cutting, the protrusion 500C, which is biased forward via the ceiling material, is pressed against the bottom wall head support portion 76C, causing the first inclined portion 76H and the inclined portion 500D to come into contact. As a result, the contact between the inclined portions prevents the support adapter 500 from lifting (opening) to the left. In other words, in a configuration where the first inclined portion 76H and the inclined portion 500D do not exist and the protrusion 500C and the bottom wall head support portion 76C come into contact with each other on planes parallel to the vertical direction during cutting (such as the configuration shown in Figures 9 and 12), or in a configuration where the bottom wall adapter support portion 500B and the bottom wall head support portion 76C do not come into contact in the front-to-back direction at all, there is a risk that the load applied during cutting will cause the support adapter to float (open) away from the support head portion 75 (to the left).

[0108] In contrast, in the configuration of Modification Example 6, when the support adapter 500 attempts to lift up, the first inclined portion 76H and the inclined portion 500D engage with each other, preventing the support adapter 500 from moving away from the support head 75. This prevents, for example, deformation or damage to the bolt BL5 supporting the support adapter 500 or the support head 75 due to the support adapter 500 lifting up. Furthermore, because the load on the support adapter 500 is transmitted to the support head 75, the load is prevented from concentrating on the bolt BL5 and damaging the bolt BL5. Note that Modification Example 6 uses an inclined structure to prevent the support adapter from lifting up. However, to prevent the support adapter from lifting up, the support adapter 500 (at least a part of it) provided on the left side of the support head 75 can be configured to be positioned to the right of the support head 75 (at least a part of it) during cutting in the second state, so that when the support adapter 500 attempts to lift up, the left side surface of the support adapter 500 (part of it) located to the right of the support head 75 comes into contact with the right side surface of the support head 75. In other words, lifting can be prevented even with an engagement structure such as a concave or convex portion. For example, one end of the bottom wall adapter support portion 500B may be configured to have a concave portion rather than a slope, and a convex portion on the support adapter 500 side. This allows for surface contact between the bottom wall head support portion 76C and the ceiling material even in the first state. In the case of Variation 6, the first sloped portion 76H may cause burrs on the edge of the ceiling material after cutting. However, in this embodiment, the angle of the first sloped portion 76H is small to prevent burrs from occurring so as not to affect work. Because there is a trade-off between the degree to which the first sloped portion 76H prevents lifting of the support adapter 500 and the degree to which burrs are prevented, it is recommended to adjust the angle of the first sloped portion 76H based on the actual application, etc.

[0109] In the above-described embodiments, the workpiece is a light-weight ceiling material having a U-shaped cross section, but the present invention is not limited to this and can be applied to a work machine that cuts the workpiece while supporting it at two different points in the direction of movement of the blade 60 during cutting. For example, the present invention can be applied to a work machine that cuts workpieces having an L-shaped or T-shaped cross section.

[0110] 10...Shearing tool (work machine), 40...Motor, 60...Blade (cutting blade), 64...Controller, 70...Head unit (support mechanism), 75...Support head unit, 78...Support adapter (support position change member), 90...First light ceiling material (light ceiling material), 92...Second light ceiling material (light ceiling material), 100...Support adapter (support position change member), 200...Support adapter (support position change member), 300...Support adapter (support position change member), 400...Support adapter (support position change member), P1...First support position, P2...Second support position, L...Distance between the first support position and the second support position

Claims

1. A work machine comprising: a support mechanism for supporting light-weight ceiling material; and a cutting blade configured to be movable in a predetermined direction and to cut the light-weight ceiling material when moved to one side in the predetermined direction, wherein the support mechanism is configured to support the light-weight ceiling material from one side in the predetermined direction at a first support position and a second support position located on one side of the predetermined direction relative to the first support position, and is configured to be able to change the distance between the first support position and the second support position in the predetermined direction.

2. The work machine described in claim 1, wherein the support mechanism includes a support head portion on which the light ceiling material is set, and a support position changing member attached to the support head portion so as to be able to support the light ceiling material, and the distance between the first support position and the second support position in the specified direction is changed depending on the attachment state of the support position changing member to the support head portion.

3. A work machine as described in claim 2, wherein the support position changing member supports the light-weight ceiling material at the first support position or the second support position.

4. A work machine as described in claim 3, wherein the support position changing member is attached to the support head portion so as to be movable between a first position and a second position, and the distance between the first support position and the second support position in the specified direction is changed by moving the support position changing member to the first position or the second position.

5. A work machine according to claim 4, wherein said support position changing member is attached to said support head portion so as to be movable in a direction intersecting said predetermined direction.

6. A work machine according to claim 4, wherein said support position changing member is attached to said support head portion so as to be rotatable about an axis extending in a direction intersecting said predetermined direction.

7. A work machine as described in claim 5 or claim 6, wherein when the support position changing member is located at the first position, the support head portion supports the light-weight ceiling material at the first support position and the support position changing member supports the light-weight ceiling material at the second support position, and when the support position changing member is located at the second position, the second support position is changed to one side in a predetermined direction and the support head portion supports the light-weight ceiling material at the first support position and the second support position.

8. A work machine according to claim 4, wherein when said support position changing member moves from said first position to said second position, said support position changing member moves relatively to one side in said predetermined direction with respect to said support head portion.

9. A work machine as described in claim 2, wherein the support position changing member is configured to be removable from the support head portion, and the distance between the first support position and the second support position in the specified direction is changed by removing the support position changing member from the support head portion.

10. A work machine as described in claim 9, wherein, when the support position change member is attached to the support head portion, the support head portion supports the light-weight ceiling material at the first support position and the support position change member supports the light-weight ceiling material at the second support position, and when the support position change member is detached from the support head portion, the support head portion supports the light-weight ceiling material at the first support position and the second support position and the second support position is changed to one side in a specified direction.

11. A work machine as described in claim 9, wherein, when the support position change member is attached to the support head portion, the support position change member supports the light-weight ceiling material at the first support position and the support head portion supports the light-weight ceiling material at the second support position, and, when the support position change member is detached from the support head portion, the support head portion supports the light-weight ceiling material at the first support position and the second support position and the first support position is changed to one side in a specified direction.

12. A work machine as described in claim 1, comprising: a motor that moves the cutting blade by driving it; and a controller that controls the driving of the motor, wherein the controller detects when cutting of the light-weight ceiling material by the cutting blade is completed, and when cutting of the light-weight ceiling material by the cutting blade is completed, the controller stops or reverses the rotation of the motor.

13. A work machine capable of cutting a first light-weight ceiling material and a second light-weight ceiling material having different dimensions in a specified direction, comprising: a support mechanism that supports the first light-weight ceiling material and the second light-weight ceiling material at two different positions in the specified direction; and a cutting blade that is configured to be movable in the specified direction and cuts the first light-weight ceiling material or the second light-weight ceiling material supported by the support mechanism when moving to one side in the specified direction, wherein the support mechanism is configured to be switchable between a first state in which it supports the first light-weight ceiling material and a second state in which it supports the second light-weight ceiling material.

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