Work machine

Abstract

To enhance workability of when changing the orientation of a blade.SOLUTION: In a feed screw mechanism 40 of a shearing tool 10, a lifter nut 52 of a lifter 50 is threaded onto a male thread 48A of a drive shaft 48, and rotation of the drive shaft 48 causes the lifter nut 52 to reciprocate in a longitudinal direction. Furthermore, a blade 66 is fixed to a front end of a lifter shaft 54, and a rear end of the lifter shaft 54 is connected to the lifter nut 52 integrally movably in the longitudinal direction and relatively rotatably about an axis in the longitudinal direction. This configuration allows a rotational position of the blade 66 relative to a housing 20 to be changed without changing a position of the blade 66 in the longitudinal direction. Specifically, the longitudinal position of the blade 66 can be maintained with no stopper defining a rotation range of the blade 66 being provided. Thereby, workability of when changing the orientation of the blade 66 can be enhanced.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] The electric cutting machine (working machine) described in Patent Document 1 below has a drive shaft that rotates when driven by a motor, a lifter that is screwed onto the drive shaft, and a blade that is fixed to the tip of the lifter. When the drive shaft rotates, the lifter moves forward together with the blade, and the workpiece supported by the head is sandwiched between the blade and the head and cut.

[0003] Furthermore, in the electric cutting machine, the orientation of the blade relative to the workpiece can be changed manually by the operator. Specifically, by rotating the guide mechanism that guides the blade around the axis of the lifter, the blade rotates together with the guide mechanism, thereby changing the orientation of the blade relative to the workpiece. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-024840 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-described electric cutting machine has room for improvement in the following respects. Specifically, when the guide mechanism rotates, the blade and lifter rotate relative to the drive shaft. Because the lifter is threadedly engaged with the drive shaft, the initial position of the lifter in the front-to-rear direction changes when the lifter rotates relative to the drive shaft. Therefore, to prevent the initial position of the lifter from changing significantly, a stopper is provided to limit the rotation range of the guide mechanism. Specifically, the stopper limits the rotation range of the guide mechanism to 180 degrees or less. As a result, when changing the orientation of the blade, the guide mechanism must be rotated within a rotation range of 180 degrees or less, which may be inconvenient for the operator. This may reduce the ease of use when changing the orientation of the blade.

[0006] SUMMARY OF THE INVENTION In consideration of the above, an object of the present invention is to provide a work machine that can improve workability when changing the orientation of the blade. [Means for solving the problem]

[0007] One or more embodiments of the present invention are a work machine comprising a motor, a drive shaft having a drive side thread portion that rotates around an axis in the fore-and-aft direction when driven by the motor, a lifter having a lifter follower portion that is threaded onto the drive side thread portion and moves back and forth in the fore-and-aft direction when the drive shaft rotates, a housing that accommodates the motor and the drive shaft, and a blade connected to the lifter follower portion so that it can move integrally in the fore-and-aft direction, wherein the blade is configured to be rotatable relative to the lifter follower portion around an axis in the fore-and-aft direction.

[0008] One or more embodiments of the present invention are a work machine in which the lifter has a lifter shaft extending in the fore-and-aft direction, the blade is connected to the front end of the lifter shaft, the rear end of the lifter shaft is connected to the lifter follower, and the blade is connected to the lifter shaft so as to be movable integrally in the fore-and-aft direction and to be rotatable relative to the lifter shaft around the fore-and-aft direction as an axis, or the lifter shaft is connected to the lifter follower so as to be movable integrally in the fore-and-aft direction and to be rotatable relative to the lifter shaft around the fore-and-aft direction as an axis.

[0009] In one or more embodiments of the present invention, the housing is provided with a shaft support portion in front of the lifter follower portion that supports the lifter shaft so that it can move in the fore-and-aft direction, and the rear end portion of the lifter shaft is supported by the lifter follower portion so that it can move integrally in the fore-and-aft direction and can rotate relatively around the fore-and-aft direction as an axis.

[0010] In one or more embodiments of the present invention, the shaft support portion is rotatable relative to the housing around the fore-and-aft direction as an axis, and head plates connected to the shaft support portion are provided on both sides of the blade in the thickness direction, the lifter shaft is configured to be rotatable relative to the head plates, and the head plates regulate the rotation of the blade around the fore-and-aft direction as an axis.

[0011] One or more embodiments of the present invention are a work machine in which the lifter follower is configured to be unable to rotate relative to the housing around the fore-and-aft direction as an axis, but is able to move relative to the housing in the fore-and-aft direction.

[0012] In one or more embodiments of the present invention, the lifter follower is formed in a cylindrical shape with the fore-and-aft direction as its axial direction, the inner periphery of the lifter follower is provided with a driven side screw portion that is threaded into the drive side screw portion, the lifter follower is provided with a rotation regulating portion that protrudes in a direction perpendicular to the fore-and-aft direction, and the rotation regulating portion engages with the housing, thereby preventing the lifter follower from rotating relative to the housing but allowing it to move relative to the housing in the fore-and-aft direction.

[0013] In one or more embodiments of the present invention, the housing is provided with a detection switch that detects a position of the lifter, and the detection switch is turned on and off by the rotation restrictor.

[0014] One or more embodiments of the present invention are a work machine in which the rotation regulating portion extends in the fore-and-aft direction, and an inclined portion is formed at one end of the rotation regulating portion in the fore-and-aft direction for pressing the detection switch, and the inclined portion is inclined in the protruding direction of the rotation regulating portion as it moves toward the other side in the fore-and-aft direction.

[0015] In one or more embodiments of the present invention, the housing is composed of a housing member divided into two in the left-right direction, and the housing member is provided with a lifter support portion that supports the rotation regulating portion from the outside in the left-right direction.

[0016] In one or more embodiments of the present invention, the housing extends in the fore-and-aft direction, houses the drive shaft and the lifter, and includes a handle portion that is gripped by an operator, and a handle end portion that is provided in front of the handle portion, extends out on both sides in the up-and-down direction relative to the handle portion, and supports the shaft support portion, and the housing is provided with a control switch for controlling the motor, and the control switch is located in the handle end portion.

[0017] One or more embodiments of the present invention are a work machine in which the housing is provided with a detection switch that detects the position of the lifter, and the detection switch is located in the handle end portion.

[0018] One or more embodiments of the present invention are a work machine in which the housing has a handle guard, the handle guard extends in the fore-and-aft direction below the handle portion, the front end of the handle guard is connected to the lower end of the handle end portion, and the wiring of the control switch and the detection switch is routed within the handle guard.

[0019] One or more embodiments of the present invention are a work machine that is provided with a holding mechanism that restricts rotation of the lifter shaft relative to the lifter follower and releases the restriction on rotation of the lifter shaft when a rotational force greater than a predetermined value is applied to the lifter shaft.

[0020] In one or more embodiments of the present invention, the holding mechanism is a work machine configured to include a blocking member that is held on one of the lifter follower and the lifter shaft and engages with the other of the lifter follower and the lifter shaft to restrict forward movement of the lifter shaft, and a biasing member that biases the lifter shaft.

[0021] In one or more embodiments of the present invention, the biasing member restricts the rotation of the lifter shaft about an axis in the fore-and-aft direction relative to the lifter follower when the rotation position of the lifter shaft about an axis in the fore-and-aft direction relative to the lifter follower is a predetermined position, and weakens the restriction on the rotation of the lifter shaft about an axis in the fore-and-aft direction relative to the lifter follower when the rotation position of the lifter shaft about an axis in the fore-and-aft direction relative to the lifter follower is not a predetermined position. [Effects of the Invention]

[0022] According to the work machine having the above configuration, it is possible to improve the workability when changing the orientation of the blade. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 2 is a side view showing the shearing tool according to the embodiment, as viewed from the right side. [Figure 2] 2 is a side view of the shear tool shown in FIG. 1 with the right housing member removed. FIG. [Figure 3] 3 is a cross-sectional view (cross-sectional view taken along line 3-3 in FIG. 2) of the feed screw mechanism shown in FIG. 2 as seen from below. [Figure 4] 4 is a cross-sectional view seen from below showing the lifter and blade shown in FIG. 3 in a state where they are placed at a stop position. FIG. [Figure 5] 5 is a cross-sectional view (cross-sectional view taken along line 5-5 in FIG. 2) showing the inside of the rear end portion of the head portion shown in FIG. 2 as seen from the front side. [Figure 6] 4 is an enlarged cross-sectional view showing the coupled state of the lifter nut and the lifter shaft shown in FIG. 3. FIG. [Figure 7] 7 is a cross-sectional view (cross-sectional view taken along line 7-7 in FIG. 6) seen from the front side, showing the coupled state of the lifter nut and the lifter shaft shown in FIG. 6. [Figure 8] 3 is a side view showing a state in which the head unit shown in FIG. 2 is rotated 180 degrees. FIG. [Figure 9] 8 is a cross-sectional view corresponding to FIG. 7, showing a modified example of the holding mechanism. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, a shearing tool 10 as a work machine according to this embodiment will be described with reference to the drawings. Note that the arrows UP, FR, and RH shown as appropriate 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.

[0025] As shown in Fig. 1, the shearing tool 10 is a power tool that shears a workpiece W, such as a light-weight ceiling material used in a suspended ceiling of a building. Here, the workpiece W is formed in a long columnar shape, and is formed into a substantially U-shape when viewed in the longitudinal direction. As shown in Figs. 1 and 2, the shearing tool 10 includes a housing 20, a motor 30, a feed screw mechanism 40, a blade 66, a head unit 70, and a controller 80.

[0026] (About Housing 20) The housing 20 forms the outer shell of the shearing tool 10 excluding the head portion 70, and extends in the front-to-rear direction as a whole. The housing 20 is composed of housing members 22L and 22R (see FIGS. 3 and 5) that are divided into two in the left-to-right direction, and the housing 20 is formed by assembling the housing members 22L and 22R to each other. The housing 20 is composed of 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.

[0027] The handle housing 20A has a handle portion 20C that is gripped by the operator, and the handle portion 20C is formed into a cylindrical shape that extends in the front-to-rear direction. A handle end portion 20D is provided at the front end of the handle housing 20A, in front of the handle portion 20C, and the handle end portion 20D protrudes further up and down than the handle portion 20C on both sides. A handle guard 20E is provided below the handle portion 20C, and the handle guard 20E is formed into a cylindrical shape that extends in the front-to-rear direction. The front end of the handle guard 20E is connected to the lower end of the handle end portion 20D, and the rear end of the handle guard 20E is bent upward and connected to the rear end of the handle portion 20C.

[0028] A pair of upper and lower support pieces 20F (see FIGS. 2 and 5) serving as lifter supports are provided in the portions of the housing members 22L, 22R that form the handle portion 20C. The support pieces 20F are formed in a generally elongated plate shape with the plate thickness direction in the up-down direction and extending in the front-rear direction, and protrude inward in the left-right direction from the housing members 22L, 22R. A predetermined gap is formed between the tips of the upper support pieces 20F and between the tips of the lower support pieces 20F.

[0029] A trigger 24 is provided at the front end of the handle portion 20C to command the start of movement of a blade 66 (to start shearing), which will be described later. The trigger 24 protrudes downward from the handle portion 20C so that it can be pulled upward. A trigger switch 26 serving as a control switch is provided in front of the trigger 24 in the handle end portion 20D. When the trigger 24 is pulled, the trigger switch 26 is switched from off to on. When the trigger 24 is released from being pulled, the trigger switch 26 is switched from on to off. The trigger switch 26 is electrically connected to a controller 80, which will be described later, and outputs an output signal to the controller 80 in response to the pulling of the trigger 24. Specifically, a wire 26A extending forward from the trigger switch 26 is bent downward and routed within the handle guard 20E. The wire 26A routed within the handle guard 20E is then connected to the controller 80 housed in the motor housing portion 20B.

[0030] As shown in Figures 2 and 3, the handle end portion 20D is provided with a support mechanism serving as a shaft support portion. The support mechanism includes a guide sleeve 27, a support guide 28, and a fixed plate 29. The guide sleeve 27 is formed in a generally cylindrical shape with its axial direction extending in the front-to-rear direction. The guide sleeve 27 has four female thread portions 27A, two on each side, into which bolts BL3 can be threaded. The support guide 28 is formed in a generally cylindrical shape with its axial direction extending in the front-to-rear direction. The support guide 28 (at its rear portion) is rotatably supported by the guide sleeve 27 (at its inner surface). In other words, the support guide 28 is rotatably supported by the handle end portion 20D. A groove 28B extending in the circumferential direction is formed on the outer periphery of the rear portion of the support guide 28, and the bolt BL3 partially fits into the groove, thereby preventing the support guide 28 from coming loose (restricting forward movement). The rear end of the support guide 28 is provided with a flange 28C that protrudes radially outward. This flange 28C engages with the rear end of the guide sleeve 27 to prevent the support guide 28 from slipping out (preventing forward movement). The front portion of the support guide 28 protrudes forward from the housing 20. A pair of upper and lower slits 28A are formed in the front portion of the support guide 28 for arranging a blade 66 (described later) (only the upper slit 28A is shown in FIG. 3). The slits 28A extend in the front-rear direction and penetrate vertically, with the front end of the slits 28A opening forward. The front portion of the support guide 28 is provided with a female thread 28D for fixing a blade holder 71 (described later) to the support guide 28. A bolt BL1 (described later) can be threaded into the female thread 28D. The fixing plate 29 is a plate-shaped member that extends vertically. There are two fixing plates 29 (a pair of left and right plates), which support the outer peripheral surface of the guide sleeve 27 and have a central portion 29A with a through-hole through which the bolt BL3 is inserted, and an extension portion 29B extending vertically from the central portion and with a through-hole through which the bolt BL4 can be inserted. The bolt BL4 is supported (fixed) to the housing 20 (handle end portion 20D), and the fixing plates 29 are supported (fixed) to the housing 20 (handle end portion 20D) by inserting the bolt BL4 into the pair of upper and lower extension portions 29B.By fixing the fixed plate 29 to the housing 20, the guide sleeve 27 supported by the fixed plate 29, the support guide 28 supported by the guide sleeve 27, and the blade holder 71 (described later) supported by the support guide 28 are each configured to be indirectly supported by the housing 20.

[0031] As shown in Figure 2, the motor housing portion 20B is formed in a generally flat shape with its thickness extending in the left-right direction, and the rear ends of the handle portion 20C and the handle guard 20E are connected to the front end of the motor housing portion 20B. A battery mounting portion 20G is provided at the rear end of the motor housing portion 20B. A battery 82 is detachably mounted in the battery mounting portion 20G from above. The battery 82 is electrically connected to a controller 80 (described later), and power is supplied to the motor 30 (described later) via the controller 80. An intake port 20I is formed in the lower portion of the motor housing portion 20B, and an exhaust port 20H is formed near the center in the vertical direction.

[0032] (Regarding motor 30) The motor 30 is a brushless motor and is housed in the vertically central portion of the motor housing portion 20B. The motor 30 has a motor shaft 30A whose axis is in the front-to-rear direction. The rear end of the motor shaft 30A is rotatably supported by a motor bearing 32 held in the housing 20, and the front end of the motor shaft 30A is rotatably supported by a motor bearing 34 held in the housing 20. A pinion gear 30B is formed on the front end of the motor shaft 30A. The motor 30 is electrically connected to and driven under the control of the controller 80. A fan 31 is provided on the motor shaft 30A. When the fan 31 rotates, air entering through the air intake 20I moves rearward to cool the controller 80, then moves further rearward to near the rear of the motor 30, and then moves forward to cool the motor 30. The air then reaches the fan 31 and is exhausted to the outside of the housing 20 through an exhaust port 20H located to the side of the fan 31.

[0033] (Regarding the lead screw mechanism 40) The feed screw mechanism 40 is composed of a transmission gear 42, a drive shaft 48 as a drive shaft, a lifter 50, an initial position detection switch 62 as a detection switch for detecting the initial position of the lifter 50, and a stop position detection switch 64 as a detection switch for detecting the stop position of the lifter 50.

[0034] The transmission gear 42 is held by a gear holder 44 so as to be rotatable integrally therewith. The gear holder 44 is formed in a generally stepped, bottomed cylindrical shape that is open to the front, and the diameter of the front portion of the gear holder 44 is set larger than the diameter of the rear portion of the gear holder 44. The transmission gear 42 is formed in a generally cylindrical shape with the front-to-rear direction as the axial direction. The front portion of the gear holder 44 is fitted into the transmission gear 42, and the transmission gear 42 is connected to the gear holder 44 so as to be rotatable integrally therewith. The transmission gear 42 is disposed above the front end of the motor shaft 30A of the motor 30, and the rear portion of the gear holder 44 is rotatably supported by a gear bearing 46 held in the housing 20. External teeth are formed on the outer periphery of the transmission gear 42, and the external teeth mesh with the pinion gear 30B of the motor shaft 30A.

[0035] The drive shaft 48 is formed in a generally cylindrical shape with its axial direction extending in the front-to-rear direction. The drive shaft 48 is housed in the handle portion 20C and is disposed in front of and coaxial with the transmission gear 42. The rear end of the drive shaft 48 is rotatably supported in front of the transmission gear 42 by a shaft bearing 49 held in the housing 20. The rear end of the drive shaft 48 is inserted into the center of the gear holder 44 and is connected to the gear holder 44 so as to be rotatable integrally therewith. As a result, when the motor 30 is driven, the drive shaft 48 rotates about an axis extending in the front-to-rear direction. A male thread 48A serving as a drive-side thread is formed on the outer periphery of the drive shaft 48, except for the rear end.

[0036] The lifter 50 is formed in a generally elongated shape extending in the front-to-rear direction as a whole. The lifter 50 includes a lifter nut 52 as a lifter follower that constitutes the rear end of the lifter 50, and a lifter shaft 54.

[0037] 2 to 5, the lifter nut 52 is formed in a generally cylindrical shape with its axial direction extending in the front-to-rear direction. A female thread 52A serving as a driven-side thread portion is formed on the inner peripheral portion of the rear portion of the lifter nut 52. The female thread 52A is threadably engaged with the male thread 48A of the drive shaft 48, and the lifter nut 52 is disposed radially outward of the drive shaft 48. In other words, the drive shaft 48 and the lifter 50 are threadably engaged with each other.

[0038] The lifter nut 52 is provided on its outer periphery with a pair of upper and lower restriction ribs 52B (see FIGS. 2 and 5) as rotation restriction portions. The restriction ribs 52B protrude outward in the up-down direction from the lifter nut 52 and extend in the front-rear direction. The support pieces 20F of the housing 20 described above are adjacent to both left and right sides of the restriction rib 52B with a predetermined gap therebetween. Thus, the lifter nut 52 is connected to the housing 20 so as to be non-rotatable relative to the housing 20 (in a state in which relative rotation is restricted) but movable relative to the housing 20 in the front-rear direction. Rotation of the drive shaft 48 causes the lifter 50 to move in the front-rear direction. Specifically, the lifter 50 moves back and forth between an initial position (position indicated by a solid line in FIG. 2) and a stop position (position indicated by a two-dot chain line in FIG. 2). Inclined portions 52C are formed at both longitudinal (front-rear direction) ends of the restriction rib 52B. When viewed from the left and right, the inclined portion 52C is inclined toward the inside in the longitudinal direction of the restricting rib 52B (inside in the front-rear direction) as it extends toward the outside in the radial direction (outside in the up-down direction) of the lifter nut 52. Also, an accommodating recess 52D (see FIGS. 4 and 5) for accommodating a shaft connecting portion 54A of a lifter shaft 54, which will be described later, is formed in the center of the front surface of the lifter nut 52. The accommodating recess 52D is formed in a recessed shape that is open toward the front side, and is formed in a circular shape when viewed from the front side.

[0039] The lifter shaft 54 ​​extends in the front-rear direction and is formed in a generally cylindrical shape with a bottom that is open to the rear. A shaft connecting portion 54A is formed at the rear end of the lifter shaft 54, and the outer diameter of the shaft connecting portion 54A is larger than the outer diameter of the other portions. The shaft connecting portion 54A is received in the receiving recess 52D of the lifter nut 52 and is rotatably supported by the inner circumferential surface of the receiving recess 52D.

[0040] Here, the shaft connecting portion 54A is connected to the lifter nut 52 by a retaining mechanism 56 so as to be immovable relative to the lifter nut 52 in the front-rear direction. As shown in FIG. 4, the retaining mechanism 56 has a retaining ring 58 serving as a blocking member and a wave washer 60 serving as a biasing member. The retaining ring 58 is disposed adjacent to the front side of the shaft connecting portion 54A, and the outer periphery of the retaining ring 58 is engaged with the inner periphery of the accommodating recess 52D. The wave washer 60 is disposed between the rear end surface of the lifter shaft 54 ​​and the bottom surface of the accommodating recess 52D, and biases the lifter shaft 54 ​​forward. As described above, the lifter shaft 54 ​​is connected to the lifter nut 52 so as to be immovable relative to the lifter nut 52 in the front-rear direction.

[0041] In the holding mechanism 56, the wave washer 60 biases the lifter shaft 54 ​​forward, and the shaft connecting portion 54A abuts against the retaining ring 58. As a result, the lifter shaft 54 ​​is held by the frictional force between the wave washer 60 and the lifter shaft 54 ​​and the frictional force between the shaft connecting portion 54A and the retaining ring 58, and the relative rotation of the lifter shaft 54 ​​with respect to the lifter nut 52 is limited. When a rotational force equal to or greater than a predetermined value is input to the lifter shaft 54, the holding state of the lifter shaft 54 ​​by the holding mechanism 56 is released, and the lifter shaft 54 ​​rotates relative to the lifter nut 52. Specifically, the biasing force of the wave washer 60 is set so that the holding state of the lifter shaft 54 ​​by the holding mechanism 56 is released when the lifter shaft 54 ​​is manually rotated by an operator. In addition, the lifter nut 52 is provided with a step portion 52E, which prevents the lifter shaft 54 ​​from retracting relative to the lifter nut 52 and causing the wave washer 60 to be excessively compressed, for example, when an excessive load is applied to the blade 66.

[0042] When the lifter 50 is in the initial position, the front portion of the drive shaft 48 is inserted into the interior of the lifter shaft 54 ​​so as to be relatively movable. The front end portion of the lifter shaft 54 ​​is inserted into the support guide 28 and is supported by the support guide 28 so as to be relatively movable in the front-rear direction.

[0043] As shown in FIG. 2, the initial position detection switch 62 is a microswitch housed in the rear end of the handle guard 20E and disposed below the drive shaft 48. The initial position detection switch 62 has a switch portion (switch plunger) protruding upward from the initial position detection switch 62. Operating (pressing) the switch portion switches the initial position detection switch 62 between on and off. When the lifter 50 is in the initial position, the inclined portion 52C of the lower restriction rib 52B of the lifter nut 52 presses the switch portion of the initial position detection switch 62 downward, switching the initial position detection switch 62 from off to on. The initial position detection switch 62 is electrically connected to the controller 80 and outputs a detection signal to the controller 80. Specifically, a wiring 62A extending downward from the initial position detection switch 62 is routed within the rear end of the handle guard 20E, bent rearward, and connected to the controller 80 in the motor housing portion 20B.

[0044] The stop position detection switch 64 is a microswitch, similar to the initial position detection switch 62, and is housed in the rear end of the handle end portion 20D and disposed above the drive shaft 48. The stop position detection switch 64 has a switch portion (switch plunger) that protrudes downward from the stop position detection switch 64. When the lifter 50 is in the stopped position, the inclined portion 52C of the upper restriction rib 52B of the lifter nut 52 presses the switch portion of the stop position detection switch 64 upward, switching the stop position detection switch 64 from OFF to ON. The stop position detection switch 64 is electrically connected to the controller 80 and outputs a detection signal to the controller 80. Specifically, a wiring 64A extending upward from the stop position detection switch 64 is folded back and routed in the vertical direction within the handle end portion 20D, passing through the left side of the lifter shaft 54. Furthermore, the wiring 64A is bent rearward at the lower end of the handle end portion 20D, routed inside the handle guard 20E, and connected to the controller 80 inside the motor housing portion 20B.

[0045] (About Blade 66) As shown in Figures 2 and 3, the blade 66 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. A screw 68 fastens a vertically intermediate portion of the rear end of the blade 66 to the front end of the lifter shaft 54. This allows the blade 66 to be connected to the lifter 50 so as to be movable together in the front-rear direction, and the lifter shaft 54 ​​also connects the blade 66 to the lifter nut 52 so as to be rotatable relative to the lifter 50 around the front-rear direction as an axis. That is, the blade 66 moves back and forth in the front-rear direction together with the lifter 50 between the initial position and the stop position. The rear end of the blade 66 is inserted into the slit 28A of the support guide 28. A cutting edge 66A for cutting the workpiece W is formed at the front end of the blade 66. The cutting edge 66A is formed in a generally V-shape that protrudes forward when viewed from the left-right direction.

[0046] In the initial position of the blade 66, the blade 66 is disposed adjacent to the front side of the housing 20 and is disposed behind the workpiece W (see FIG. 1). When the blade 66 moves forward from the initial position, it clamps the workpiece W from both front and rear sides together with the head unit 70 (described later), and shears the workpiece W. Furthermore, when the blade 66 stops, it is set to complete the shearing of the workpiece W. The rotation of the blade 66 about an axis in the front-to-rear direction is restricted by the head unit 70 (holder plate 72) (described later).

[0047] (Regarding the head unit 70) As shown in FIGS. 1 to 3, the head unit 70 includes a blade holder 71, a connecting portion 73, and a support head unit 74. The blade holder 71 has a pair of left and right holder plates 72 serving as head plates. The holder plates 72 are made of a metal plate and are formed into a generally rectangular plate shape with the left-right direction as the plate thickness direction. As shown in FIG. 5, a fixing portion 72A is formed in the middle of the holder plate 72 in the up-down direction. The fixing portion 72A is formed into a generally arc-like shape that protrudes outward in the left-right direction when viewed from the front. The fixing portion 72A is disposed radially outward of the front portion of the support guide 28 and is fastened and fixed to the support guide 28 by a pair of front and rear bolts BL1. As a result, the blade holder 71 (holder plate 72) is connected to the housing 20 by the support guide 28 so as to be rotatable (integrally with the support guide 28) around an axis in the front-rear direction.

[0048] The pair of holder plates 72 are disposed opposite each other with a predetermined gap in the left-right direction. The upper portions of the pair of holder plates 72 are spaced apart by the thickness of the connecting portion 73 (described later) to support the connecting portion 73. The opposing distance between the lower portions of the pair of holder plates 72 is set slightly longer than the thickness of the blade 66 by interposing a spacer (not shown) between the pair of holder plates 72 that is thicker than the blade 66. The blade 66 is disposed between the pair of holder plates 72. As a result, the blade holder 71 covers the blade 66 from both left and right sides, and the rotation of the blade 66 is restricted by (the lower portion of) the holder plate 72. That is, the lifter shaft 54 ​​is configured to be rotatable relative to the holder plate 72 (support guide 28). However, by disposing the holder plates 72 on both sides of the blade 66 in the thickness direction, the relative rotation of the blade 66 and the lifter shaft 54 ​​with respect to the holder plate 72 is restricted, and the blade 66 moves forward and backward between the pair of holder plates 72. In other words, the holder plate 72 supports the blade 66 so that it can move in the front-to-rear direction while restricting rotation of the blade 66 about an axis in the front-to-rear direction. When the blade holder 71 (holder plate 72) is rotated about an axis in the front-to-rear direction, the blade 66 and the lifter shaft 54 ​​are pressed by the holder plate 72 and rotate about an axis in the front-to-rear direction. For example, when the blade holder 71 is rotated 180 degrees from the state shown in FIG. 2, the state (position) of the blade 66 and blade holder 71 becomes as shown in FIG. 8.

[0049] The connecting portion 73 is made of a metal plate and is formed in a substantially elongated plate shape with its thickness in the left-right direction and extending in the front-rear direction. The connecting portion 73 is disposed between the upper ends of the pair of holder plates 72 and is fastened and fixed to the holder plates 72 by bolts BL2.

[0050] The support head portion 74 is disposed in front of the blade holder 71 at a distance. The support head portion 74 has a pair of left and right support plates 75, which are made of metal plate material and formed into a plate shape with the plate thickness direction in the left-right direction. The pair of support plates 75 are disposed outside the connecting portion 73 in the left-right direction, and the upper end portions of the support plates 75 are fastened and fixed to the front end portion of the connecting portion 73 by bolts BL2. As a result, the pair of support plates 75 are disposed facing each other with a predetermined gap left and right.

[0051] As shown in FIG. 1 , the rear end of the support plate 75 is formed with multiple (four in this embodiment) support recesses 75A (cutouts). The support recesses 75A are recessed and open to the rear, and extend laterally. When cutting the workpiece W, both ends of the workpiece W, as viewed in the longitudinal direction, are inserted into the support recesses 75A, and the workpiece W is set (supported) on the support head 74. In other words, the support head 74 functions as a support for the workpiece W. Because the support plate 75 receives a load from the blade 66 during cutting, the connecting portion 73 is thicker than the blade 66 and the holder plate 72 to provide strong support. The head 70 is formed in a U-shape by the blade holder 71, connecting portion 73, and support head 74, and the open portion of the U-shape serves as an opening for receiving the workpiece W when it is set on the support head 74. By rotating the head portion 70, the direction of this receiving opening can be changed.

[0052] (Regarding the controller 80) 2, the controller 80 is accommodated in the lower end of the motor housing portion 20B of the housing 20 and is held by the housing 20. The trigger switch 26, the motor 30, the initial position detection switch 62, and the stop position detection switch 64 are electrically connected to the controller 80. The controller 80 detects the initial position of the lifter 50 based on a detection signal from the initial position detection switch 62, and detects the stop position of the lifter 50 based on a detection signal from the stop position detection switch 64. The controller 80 has an inverter circuit made up of a plurality of switching elements (e.g., FETs), and drives the motor 30.

[0053] The controller 80 controls the drive of the motor 30 based on output signals from the trigger switch 26, the initial position detection switch 62, and the stop position detection switch 64. Specifically, when the trigger switch 26 switches from off to on when the lifter 50 is in the initial position, the controller 80 drives the motor 30 in the forward direction, thereby moving the lifter 50 (blade 66) forward. Furthermore, when the operation of the trigger 24 is released and the trigger switch 26 switches from on to off while the motor 30 is driving in the forward direction, the controller 80 drives the motor 30 in the reverse direction, thereby moving the lifter 50 (blade 66) rearward. Furthermore, when the controller 80 detects the stop position of the lifter 50 (blade 66), it stops the drive of the motor 30. Furthermore, after detecting the stop position of the lifter 50 (blade 66), the controller 80 drives the motor 30 in the reverse direction based on the on signal from the trigger switch 26, thereby moving the lifter 50 (blade 66) rearward. Furthermore, when the controller 80 detects the initial position of the lifter 50 (blade 66), it stops driving the motor 30.

[0054] (Action and effect) Next, the effects of the shearing tool 10 of this embodiment will be described.

[0055] When the blade 66 is in the initial position of the shearing tool 10 configured as described above, the lower restricting rib 52B of the lifter nut 52 presses the switch portion of the initial position detection switch 62, turning the initial position detection switch 62 on. When the trigger 24 is operated and the trigger switch 26 is turned on, the motor 30 is driven in the forward direction under the control of the controller 80. This activates the feed screw mechanism 40, and the blade 66 moves forward (the forward path, one side in the front-to-rear direction) by the lifter 50. As a result, the blade 66 approaches the workpiece W, and the workpiece W supported by the support head 74 is sandwiched between the blade 66 and the support head 74, thereby shearing the workpiece W. During shearing of the workpiece W, the blade 66 is inserted into the pair of support plates 75 of the support head 74. When the blade 66 reaches the stop position, the upper restricting rib 52B of the lifter nut 52 presses the switch portion of the stop position detection switch 64, turning the stop position detection switch 64 on. As a result, the controller 80 detects the stop position and stops the forward rotation of the motor 30. This completes the cutting process on the workpiece W.

[0056] After the cutting process is completed, the driving of the motor 30 is automatically stopped, and when the trigger switch 26 is turned on again, the motor 30 is rotated in the reverse direction under the control of the controller 80, and the blade 66 is moved rearward (the return side, the other side in the front-to-rear direction) by the lifter 50 of the feed screw mechanism 40. When the blade 66 reaches the initial position, the restricting rib 52B on the lower side of the lifter nut 52 presses the switch portion of the initial position detection switch 62, turning on the initial position detection switch 62. As a result, the controller 80 detects the initial position of the lifter 50 and stops the driving of the motor 30.

[0057] In the feed screw mechanism 40 of the shearing tool 10, the lifter nut 52 of the lifter 50 is threaded onto the male thread 48A of the drive shaft 48, and rotation of the drive shaft 48 causes the lifter nut 52 to reciprocate in the front-rear direction. The blade 66 is connected to the lifter 50 so as to be movable integrally with the lifter 50 in the front-rear direction and so as to be rotatable relative to the lifter nut 52. Specifically, the blade 66 is fixed to the front end of the lifter shaft 54, and the rear end of the lifter shaft 54 ​​is connected to the lifter nut 52 so as to be movable integrally with the lifter 50 in the front-rear direction and so as to be rotatable relative to the lifter nut 52 about an axis in the front-rear direction. Therefore, when the blade 66 is rotated around the axis of the lifter shaft 54, the lifter shaft 54 ​​rotates together with the blade 66 relative to the lifter nut 52 while maintaining its front-rear position. In other words, according to this embodiment, a configuration can be achieved in which the rotational force generated when the motor 30 is driven moves the lifter 50 in the axial direction, but the rotational force generated when the blade 66 is rotated does not move the lifter 50 in the axial direction. This allows the rotational position of the blade 66 relative to the housing 20 to be changed without changing the position of the blade 66 in the front-to-rear direction. Specifically, the front-to-rear position of the blade 66 can be maintained without providing a stopper that defines the rotation range of the blade 66, as in the prior art. As a result, the orientation of the blade 66 can be changed without restricting the rotation range of the blade 66. Therefore, the ease of operation when changing the orientation of the blade 66 can be improved.

[0058] The support guide 28 is rotatably connected to the housing 20 around an axis in the front-rear direction, and a pair of holder plates 72 in the head portion 70 are fixed to the support guide 28. The blade 66 is disposed between the pair of holder plates 72, and the holder plates 72 restrict rotation of the blade 66 around an axis in the front-rear direction. This allows the lifter shaft 54, which is configured to be rotatable relative to the holder plates 72, to be configured to be rotatable integrally with the holder plates 72 by the blade 66. Therefore, the head portion 70 and the blade 66 can be rotated relative to the lifter nut 52 to change the rotational positions of the head portion 70 and the blade 66. The head portion 70 (blade holder 71) restricts rotation of the blade 66 around an axis in the front-rear direction, thereby guiding the movement of the blade 66 during cutting. This configuration restricts the transmission of rotational force around an axis in the front-rear direction to the lifter shaft 54 ​​compared to the prior art, thereby restricting excessive contact between the blade 66 and the head portion 70 (the lower part of the holder plates 72). For example, in the prior art, rotational force is constantly transmitted to the lifter shaft 54 ​​by the screw action, which means that the head portion is constantly subjected to the rotation of the blade, and friction with the head portion can cause wear and abnormal noise, but the present invention can suppress these problems.

[0059] Furthermore, a pair of upper and lower restricting ribs 52B are provided on the outer periphery of the lifter nut 52, and the support pieces 20F of the housing 20 are disposed adjacent to the outside of the restricting ribs 52B in the left-right direction with a predetermined gap therebetween. This allows the lifter nut 52 to be connected to the housing 20 so as to be non-rotatable relative to the housing 20 (while restricting relative rotation beyond a predetermined value) and to be relatively movable in the front-rear direction without providing any additional components. Because there is a predetermined gap between the restricting ribs 52B and the support pieces 20F, the support pieces 20F are configured not to impede the front-rear movement of the lifter nut 52. However, the lifter nut 52 can rotate relative to the housing 20 by the amount of this gap. However, this rotation is very slight and does not constitute relative rotation as defined in the present invention. In the present invention, it is preferable that the rotation of the lifter nut 52 relative to the housing 20 is restricted to less than 3 degrees, but even if it is restricted to less than 10 degrees, it is considered to be non-rotatable relative to the housing 20. Alternatively, the restricting rib 52B may be configured to protrude outward in the left-right direction from the lifter nut 52 and be supported by ribs formed on the left and right inner surfaces of the housing 20 (i.e., the positions of the restricting rib 52B and the support piece 20F may be rotated 90 degrees around the axis in the front-to-rear direction). However, by configuring the restricting rib 52B to protrude outward in the up-down direction from the lifter nut 52 as in the present invention, the left-to-right dimension of the handle portion 20C can be reduced compared to a structure in which the restricting rib 52B protrudes outward in the left-to-right direction from the lifter nut 52. This can improve the gripping performance of the handle portion 20C. In particular, with a handle portion 20C provided with a trigger 24 that protrudes downward, the operator's palm is positioned to the side of the handle portion 20C and the operator's fingers are positioned below the trigger 24. Therefore, by reducing the left-to-right dimension of the handle portion 20C, the gripping performance of the handle portion 20C can be effectively improved.

[0060] The housing 20 is composed of housing members 22L and 22R that are divided into two in the left-right direction, and a support piece 20F is formed on each of the housing members 22L and 22R. As a result, by assembling the housing members 22L and 22R to each other from the outside in the left-right direction of the lifter 50, the support piece 20F can support the restricting rib 52B from both the left and right sides. This improves the ease of assembly of the housing 20.

[0061] Additionally, the housing 20 is provided with an initial position detection switch 62 and a stop position detection switch 64 that detect the position of the lifter 50, and the initial position detection switch 62 and the stop position detection switch 64 are turned on and off by the restricting rib 52B. Specifically, the initial position detection switch 62 and the stop position detection switch 64 are turned on by the restricting rib 52B pressing the switch portions of the initial position detection switch 62 and the stop position detection switch 64. Therefore, the initial position detection switch 62 and the stop position detection switch 64 can be turned on and off by utilizing the restricting rib 52B that couples the lifter nut 52 to the housing 20 so as not to rotate relative to each other.

[0062] In addition, an inclined portion 52C for pressing the switch portions of the initial position detection switch 62 and the stop position detection switch 64 is formed at the end of the restriction rib 52B of the lifter nut 52. When viewed from the left and right, the inclined portion 52C is inclined inward in the longitudinal direction of the restriction rib 52B as it extends outward in the up-down direction. In other words, the inclined portion 52C at the front end at the top of the lifter nut 52 is inclined upward as it extends rearward. The inclined portion 52C at the rear end at the bottom of the lifter nut 52 is inclined downward as it extends forward. This allows the inclined portion 52C to effectively press the switch portions of the initial position detection switch 62 and the stop position detection switch 64. Note that similar inclined portions 52C are provided at the upper rear end and lower front end of the lifter nut 52 so that the detection switches can be pressed even when the lifter nut 52 is assembled upside down. This prevents incorrect assembly and improves assembly ease.

[0063] Furthermore, a handle end portion 20D that protrudes outward in the vertical direction is provided on the front side of the handle portion 20C, and the support guide 28, trigger switch 26, and stop position detection switch 64 are provided on the handle end portion 20D. This makes it possible to utilize the handle end portion 20D that supports the support guide 28 to provide the trigger switch 26 and stop position detection switch 64. Furthermore, the trigger switch 26 is disposed on the lower side of the lifter 50, and the stop position detection switch 64 is disposed on the upper side of the lifter 50. This makes it possible to provide the trigger switch 26 and stop position detection switch 64 on the handle end portion 20D while preventing the handle end portion 20D from becoming too large in the left-right direction.

[0064] Furthermore, the wire 26A of the trigger switch 26 and the wire 64A of the stop position detection switch 64 are routed within the handle guard 20E provided below the handle portion 20C and connected to the controller 80 of the motor housing portion 20B. This allows the wires 26A and 64A to be connected to the controller 80 without being routed through the handle portion 20C that houses the feed screw mechanism 40. This, for example, makes it easier to handle the wires 26A and 64A, contributing to improved assembly. Furthermore, the controller 80 is disposed behind the handle guard 20E. This prevents the wires 26A and 64A from becoming too long.

[0065] A retaining mechanism 56 is provided between the lifter nut 52 and the shaft connecting portion 54A of the lifter shaft 54. Specifically, the retaining mechanism 56 includes a retaining ring 58 provided on the lifter nut 52 and a wave washer 60 that biases the lifter shaft 54 ​​forward, and the shaft connecting portion 54A of the lifter shaft 54 ​​abuts against the retaining ring 58. This allows the lifter shaft 54 ​​and the lifter nut 52 to be connected so as to prevent relative movement in the front-to-rear direction, and also prevents the lifter shaft 54 ​​from rotating. When a rotational force equal to or greater than a predetermined value is input to the lifter shaft 54, the retaining state of the lifter shaft 54 ​​is released. This allows the blade 66 to be held in a predetermined rotational position during normal use, and the rotational position of the blade 66 can be changed by applying a rotational force equal to or greater than a predetermined value to the head portion 70.

[0066] In this embodiment, the rear end of the lifter shaft 54 ​​is connected to the lifter nut 52 so as to be rotatable relative to the lifter shaft 54 ​​but so as not to move relatively in the front-to-rear direction, but the blade 66 may also be connected to the front end of the lifter shaft 54 ​​while being rotatable relative to the lifter shaft 54. Also, in this embodiment, the drive shaft 48 is provided with a male thread 48A and the lifter nut 52 is provided with a female thread 52A, but the relationship of these thread engagements may be reversed, i.e., the driving side thread portion may be a female thread and the driven side thread portion may be a male thread.

[0067] Furthermore, in this embodiment, the wave washer 60 is used as the retaining mechanism (biasing member), but other methods are also possible. For example, FIG. 9 shows a modified example in which a ball plunger consisting of a ball 54B and a coil spring 54C is used as the retaining mechanism (biasing member). In the configuration shown in FIG. 9, the ball 54B, which is pressed by the coil spring 54C supported by the lifter shaft 54, engages with the engagement recess 54E formed in the accommodation recess 52D of the lifter nut 52, thereby restricting rotation of the lifter shaft 54 ​​relative to the lifter nut 52. By applying a rotational force of a predetermined magnitude or greater to the blade 66 (lifter shaft 54), the operator can disengage the ball 54B from the engagement recess 54E and rotate the lifter shaft 54 ​​relative to the lifter nut 52. That is, in the configuration shown in FIG. 9, rotation is restricted at a predetermined rotational position, but the restriction on rotation is weakened at positions other than the predetermined rotational position. 9, the lifter shaft 54 ​​engages with the lifter nut 52 every 90 degrees, making it difficult to engage the blade 66 at a fine angle, such as 45 degrees, but this has the advantage that, compared to using the wave washer 60, the click feeling transmitted to the operator makes it easier to make adjustments every 90 degrees, and that there is less friction during rotation, allowing for smooth adjustments. Also, it may be used in combination with the wave washer 60, or another biasing member (for example, an elastic O-ring) may be used in combination.

[0068] Furthermore, the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention. [Explanation of symbols]

[0069] 10 Shearing tools (work equipment) 20. Housing 20C Handle 20D handle end 20E Handle Guard 20F Support piece (lifter support part) 22L housing material 22R housing material 26 Trigger switch (control switch) 26A wiring 28 Support guide (shaft support part) 30 motor 48 Drive shaft 48A male thread (drive side thread) 50 Lifter 52 Lifter nut (lifter follower) 52A female thread (driven side thread) 52B Restriction rib (rotation restriction part) 52C Inclined section 56 Retention mechanism 58 Retaining ring (blocking member) 60 Wave washer (biasing member) 62 Initial position detection switch (detection switch) 64 Stop position detection switch (detection switch) 64A wiring 66 Blades 72 Holder plate (head plate)

Claims

1. A motor; a drive shaft having a drive-side screw portion that rotates around an axis in the front-rear direction when driven by the motor; a lifter having a lifter follower that is threadedly engaged with the drive-side threaded portion and that reciprocates in the front-rear direction as the drive shaft rotates; a housing that accommodates the motor and the drive shaft; a blade connected to the lifter follower so as to be movable integrally in the front-rear direction; Equipped with The work machine is configured so that the blade is rotatable relative to the lifter follower around an axis extending in the front-to-rear direction.

2. The lifter has a lifter shaft extending in the front-rear direction, the blade is connected to a front end of the lifter shaft, and the rear end of the lifter shaft is connected to the lifter follower, The blade is connected to the lifter shaft so as to be movable integrally in the front-rear direction and so as to be rotatable relative to the lifter shaft about an axis in the front-rear direction. or 2. The work machine according to claim 1, wherein the lifter shaft is connected to the lifter follower so as to be movable integrally with the lifter follower in the front-rear direction and so as to be rotatable relative to the lifter follower about an axis in the front-rear direction.

3. The housing is provided with a shaft support portion in front of the lifter follower portion that supports the lifter shaft movably in the front-rear direction, 3. The work machine according to claim 2, wherein a rear end of the lifter shaft is supported by the lifter follower so as to be movable integrally in the front-rear direction and so as to be rotatable relative to the lifter follower about an axis in the front-rear direction.

4. The shaft support portion is rotatable relative to the housing about an axis in the front-rear direction, a head plate connected to the shaft support portion is provided on both sides of the blade in a plate thickness direction; The work machine according to claim 3, wherein the lifter shaft is configured to be rotatable relative to the head plate, and the head plate restricts rotation of the blade about an axis extending in the front-rear direction.

5. 2. The work machine according to claim 1, wherein the lifter follower is configured to be unable to rotate relative to the housing about an axis in the front-rear direction but is movable relative to the housing in the front-rear direction.

6. The lifter follower is formed in a cylindrical shape with its axial direction extending in the front-rear direction, an inner circumferential portion of the lifter follower portion is provided with a follower-side thread portion that is threadedly engaged with the drive-side thread portion; The work machine described in claim 5, wherein the lifter follower is provided with a rotation regulating portion that protrudes in a direction perpendicular to the fore-and-aft direction, and the rotation regulating portion engages with the housing, preventing the lifter follower from rotating relative to the housing and allowing it to move relative to the housing in the fore-and-aft direction.

7. The housing is provided with a detection switch that detects the position of the lifter, The work machine according to claim 6, wherein the detection switch is turned on and off by the rotation restricting portion.

8. The work machine described in claim 7, wherein the rotation regulating portion extends in the fore-and-aft direction, and an inclined portion for pressing the detection switch is formed at one end of the rotation regulating portion in the fore-and-aft direction, and the inclined portion is inclined in the protruding direction of the rotation regulating portion as it approaches the other side in the fore-and-aft direction.

9. The housing is configured by a housing member divided into two parts in the left-right direction, 7. The work machine according to claim 6, wherein the housing member is provided with a lifter support portion that supports the rotation restricting portion from outside in the left-right direction.

10. The housing includes: a handle portion extending in the front-rear direction, accommodating the drive shaft and the lifter, and being held by an operator; a handle end portion provided on a front side of the handle portion, extending upward and downward relative to the handle portion, and supporting the shaft support portion; It is composed of 4. The work machine according to claim 3, wherein the housing is provided with a control switch for controlling the motor, the control switch being disposed in the handle end portion.

11. The housing is provided with a detection switch that detects the position of the lifter, The work machine according to claim 10, wherein the detection switch is disposed at the handle end portion.

12. The housing has a handle guard, the handle guard extending in the front-rear direction below the handle portion, and a front end of the handle guard connected to a lower end of the handle end portion, 12. The work machine according to claim 11, wherein wiring for the control switch and the detection switch is routed inside the handle guard.

13. The work machine according to claim 3, further comprising a holding mechanism that restricts rotation of the lifter shaft relative to the lifter follower and releases the restriction on rotation of the lifter shaft when a rotational force greater than a predetermined value is applied to the lifter shaft.

14. The holding mechanism includes: a blocking member that is held by one of the lifter follower and the lifter shaft and engages with the other of the lifter follower and the lifter shaft to restrict forward movement of the lifter shaft; a biasing member that biases the lifter shaft; The work machine according to claim 13, comprising:

15. The working machine described in claim 14, wherein the biasing member restricts the rotation of the lifter shaft about an axis along the fore-and-aft direction relative to the lifter follower when the rotation position of the lifter shaft about an axis along the fore-and-aft direction relative to the lifter follower is a predetermined position, and weakens the restriction on the rotation of the lifter shaft about an axis along the fore-and-aft direction relative to the lifter follower when the rotation position of the lifter shaft about an axis along the fore-and-aft direction relative to the lifter follower is not a predetermined position.

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