Electric work machine

Abstract

To detect existence or non-existence of a cover covering a cutting tool or a position of the cover accurately in an electric work machine.SOLUTION: An electric work machine includes a motor, a tool attachment part, a conductor detection part having a sensor head, and an a combination member. In the tool attachment part, a cutting tool is attached or the cutting tool is removably attached. The sensor head senses a member having conductivity in a non-contact manner. The combination member is spaced apart from the sensor head and includes a cover and an object to be detected (a detected object). The cover covers a part of an outer peripheral edge of the cutting tool. The detected object is attached to the cover or included in the cover. The cover and / or the detected object is a conductor.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a technique for detecting the presence or position of a member provided in an electric working machine. [Background technology]

[0002] Patent Document 1 discloses an electric circular saw. This electric circular saw includes a saw blade, an electric motor, a safety cover, and a change-over switch. The change-over switch includes a movable part with which the safety cover comes into contact, and a contact that is opened or closed by the movable part. When the safety cover is closed, the contact is open. When the safety cover is opened, the movable part is moved by the safety cover, thereby closing the contact. The output of the electric motor is changed depending on the state of the change-over switch (i.e., depending on the position of the safety cover). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 50-74895 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, if a foreign object is interposed between the change-over switch and the safety cover, or if a foreign object gets into the change-over switch itself, there is a possibility that the change-over switch will not operate properly according to the position of the safety cover.

[0005] In addition, since the change-over switch is disposed so as to come into contact with the safety cover, there is a possibility that the change-over switch may hinder the opening and closing of the safety cover. For example, the change-over switch may interfere with the safety cover, which may impair workability or affect the results of work.

[0006] A similar problem may occur in various electric working machines when the presence and / or position of a cover provided on the electric working machine is detected using a physical switch. One aspect of the present disclosure enables accurate detection of the presence or position of a cover covering a cutting tool in a power tool.

Means for Solving the Problems

[0007] In the present disclosure, terms such as “first” and “second” are merely intended to distinguish elements from each other and are not intended to limit the order or number of elements. Thus, the first element may be referred to as the second element, and similarly, the second element may be referred to as the first element. In addition, the first element may be provided without the second element, and similarly, the second element may be provided without the first element.

[0008] One aspect of the present disclosure provides a power tool including a motor, a tool mounting portion, a conductor detection portion, and a combination member. The tool mounting portion has a cutting tool mounted thereon or the cutting tool is detachably mounted. The cutting tool can cut a workpiece by being rotated. The tool mounting portion transmits the rotation of the motor to the cutting tool to rotate the cutting tool.

[0009] The conductor detection portion has a sensor head. The sensor head non - contactingly senses a member having conductivity. The conductor detection portion outputs a detection signal. The detection signal changes according to the distance between the sensor head and the member, the material of the member, and / or the shape of the member.

[0010] The combination member is disposed at a distance from the sensor head and includes a cover and a detection object. The cover covers a covered area on the cutting tool. The covered area is a part of the outer peripheral edge along the rotation direction of the cutting tool.

[0011] The detection object is attached to or included in the cover. The detection object is arranged such that the distance from the sensor head changes according to the position of the cover. The cover and / or the object to be detected is a conductor. The combined member is arranged such that the detection signal from the conductor detection unit varies depending on whether the cover is within a specified region. When the cover is within the specified region, the cover covers at least a predetermined range of the covered region.

[0012] In the electric working machine configured as described above, the sensor head is separated from the combined member. The detection signal from the conductor detection unit changes according to the position of the combined member. Therefore, the presence or position of the cover can be accurately detected. Specifically, at least whether the cover is within the specified region can be accurately detected.

Brief Description of the Drawings

[0013]

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Modes for Carrying Out the Invention

[0014] [1. General Overview of Embodiments] Some embodiments may provide an electric working machine having at least any one of the following features 1 to 12. · Feature 1: Motor. · Feature 2: Tool mounting portion. The tool mounting portion is configured such that a cutting tool is mounted thereon or the cutting tool is detachably mounted. The cutting tool can cut a workpiece by being rotated. · Feature 3: The tool mounting part is configured to transmit the rotation of the motor to the cutting tool to rotate the cutting tool. · Feature 4: Conductor detection part. · Feature 5: The conductor detection part has a sensor head. The sensor head is configured to non - contact sense a conductive member. · Feature 6: The conductor detection part is configured to output a detection signal. The detection signal varies according to the distance between the sensor head and the member, the material of the member, and / or the shape of the member. · Feature 7: A combined member arranged at a distance from the sensor head. · Feature 8: The combined member includes a cover. The cover is configured to cover a covered area of the cutting tool. The covered area is a part of the outer peripheral edge along the rotation direction of the cutting tool. · Feature 9: The combined member includes a detection object. The detection object is attached to or included in the cover. The detection object is arranged such that the distance from the sensor head changes according to the position of the cover. · Feature 10: The cover and / or the detection object is a conductor. · Feature 11: The combined member is arranged such that the detection signal varies according to whether the cover is within a specified area. · Feature 12: When the cover is within the specified area, the cover covers at least a predetermined range of the covered area.

[0015] In the above Feature 8, the cover covering the covered area may, for example, mean covering the covered area so that when viewed from the outside in the radial direction of the rotation radius of the cutting tool, the covered area is blocked by the cover and cannot be visually recognized and / or contacted.

[0016] That the cover is within the specified region may mean that the entire cover is within the specified region. When at least a part of the cover is outside the specified region, the cover may cover a range smaller than the predetermined range among the covered regions, or may not cover the covered region.

[0017] The cover and the object to be detected may have different physical properties from each other. For example, the cover and the object to be detected may have different materials and shapes from each other. The cover and the object to be detected may have different electrical characteristics from each other. The electrical characteristics may include characteristics such as electrical ones. The electrical characteristics may include, for example, any one or more of inductance, resistivity (in other words, conductivity), permittivity, etc. The inductance may include self-inductance and / or mutual inductance with the sensor head.

[0018] The distance between the sensor head and the object to be detected may be different when the cover is within the specified region and when it is not within the specified region. The distance may be defined in any way. The distance may be, for example, the distance between a first position on the sensor head and a second position on the object to be detected.

[0019] In the electric working machine having at least features 1 to 12, the sensor head is separated from the combined member. The detection signal from the conductor detection unit changes according to the position of the combined member. Therefore, the presence or position of the cover can be accurately detected. Specifically, at least whether the cover is within the specified region can be accurately detected.

[0020] One embodiment may include, in addition to, or instead of, at least any one of the above-described features 1 to 12, the following feature 13. · Feature 13: The conductor detection unit is adjacent to the cover in a non-contact manner.

[0021] "Adjacent without contact" may be defined in any way. "Adjacent without contact" may be defined, for example, as the conductor detection unit and the cover being arranged such that the distance between the sensor head and the detection target when the detection target is closest to the sensor head is 5 mm or more and 15 mm or less.

[0022] The electric working machine having at least features 1 to 13 can improve the detection accuracy of the presence or position of the cover. In an embodiment, in addition to or instead of at least any one of the above-described features 1 to 13, it may have the following feature 14. · Feature 14: A control circuit configured to perform a predetermined process based on the position of the cover indicated by the detection signal.

[0023] The electric working machine having at least features 1 to 12, 14 can perform an appropriate operation according to the position of the cover. In an embodiment, in addition to or instead of at least any one of the above-described features 1 to 14, it may have the following feature 15. · Feature 15: The cover is configured to be movable within a predetermined movable range including the specified area. and is.

[0024] The electric working machine having at least features 1 to 12, 15 can accurately detect the position of the movably arranged cover. In an embodiment, in addition to or instead of at least any one of the above-described features 1 to 15, it may have at least any one of the following features 16 to 17. · Feature 16: The specified area extends from a first specified position to a second specified position within the movable range. The second specified position may be a position that has moved a certain amount from the first specified position. ·Feature 17: The first specified position corresponds to the position of the cover when the cover covers the covered area and the cover is at an end of the movable range.

[0025] The electric working machine having at least Features 1-12, 15-17 can accurately detect whether the cover is within the range from the first specified position to the second specified position.

[0026] An embodiment may include, in addition to, or instead of, at least any one of the above-described Features 1 to 17, at least any one of the following Features 18 to 22. ·Feature 18: A main body portion that houses the motor and to which the combined member is attached. ·Feature 19: A support configured to rotatably support the main body portion within a predetermined range of rotation angles. ·Feature 20: The cover is configured to be in the first specified position when no external force due to contact is applied from the outside of the electric working machine. ·Feature 21: The cover is configured to abut against the support and receive the external force from the support in response to the rotation of the main body portion, and to be moved from the first specified position toward the second specified position by the external force. ·Feature 22: The cover is configured to reach the second specified position when the main body portion is rotated by the predetermined rotation angle.

[0027] In the electric working machine having at least Features 1-12, 15-22, when the main body portion is rotated with respect to the support, the cover is moved toward the second specified position, and the second specified position is included in the specified area. That is, the movement of the cover due to the rotation of the main body portion is suppressed to movement within the specified area.

[0028] An embodiment may include, in addition to, or instead of, at least any one of the above-described Features 1 to 22, the following Feature 23. ·Feature 23: The object to be detected is arranged on the cover so as to face the sensor head when the cover is at at least a specific position within the specified area.

[0029] The specific position may be the first specified position. The sensor head may have a surface facing the object to be detected. "Facing the sensor head" may mean facing the surface, and more specifically, being present at a position spaced in a direction perpendicular to the surface from the surface.

[0030] The electric working machine having at least Features 1-12, 23 can improve the detection accuracy of the presence or position of the cover. An embodiment may include, in addition to, or instead of, at least any one of the above-described Features 1 to 23, at least any one of the following Features 24 to 25. 。 ·Feature 24: The cover is configured to rotate along the circumferential direction of the cutting tool around the rotation axis of the cutting tool. ·Feature 25: The conductor detection unit is arranged to be spaced from the cover in the radial direction of the rotation radius of the cover and to face the sensor head in the radial direction of the rotation radius.

[0031] The electric working machine having at least Features 1-12, 24-25 can properly and simply space the sensor head and the cover. An embodiment may include, in addition to, or instead of, at least any one of the above-described Features 1 to 23, Feature 24 and the following Feature 26. ·Feature 26: The conductor detection unit is arranged to be spaced from the cover in the axial direction along the rotation axis and to face the sensor head in the axial direction. The electric working machine having at least Features 1-12, 24, 26 can properly and simply space the sensor head and the cover.

[0032] In certain embodiments, in addition to, or instead of, at least any one of the above-described features 1 to 26, the electric working machine may further include at least any one of the following features 27 to 28. · Feature 27: The cover includes a side plate facing the cutting tool. · Feature 28: The detection object is embedded inside the side plate and does not protrude outside the side plate.

[0033] The electric working machine having at least features 1-12, 27-28 can suppress the separation of the detection object from the cover. In certain embodiments, in addition to, or instead of, at least any one of the above-described features 1 to 26, the electric working machine may further include the above feature 27 and the following feature 29. · Feature 29: The detection object is provided on the outer surface of the side plate that does not face the cutting tool, such that the detection object protrudes from the side plate to the outer surface side.

[0034] The electric working machine having at least features 1-12, 27, 29 can easily fix the detection object to the cover. In certain embodiments, in addition to, or instead of, at least any one of the above-described features 1 to 26, the electric working machine may further include the above feature 27 and the following feature 30. · Feature 30: The detection object is provided on the inner surface of the side plate that faces the cutting tool, such that the detection object protrudes from the side plate to the inner surface side. The electric working machine having at least features 1-12, 27, 30 can easily fix the detection object to the cover.

[0035] In certain embodiments, in addition to, or instead of, at least any one of the above-described features 1 to 30, the electric working machine may further include at least any one of the following features 31 to 32. · Feature 31: The detection object is a conductor ·Feature 32: The cover has a material different from that of the object to be detected and is non-metallic.

[0036] When the cover is within the specified region, the object to be detected may face or be close to the sensor head. When the cover is at least partially out of the specified region, the object to be detected does not face the sensor head and the cover may face or be close to the sensor head.

[0037] The electric working machine having at least Features 1-12, 31-32 can accurately detect the presence or position of the cover based on the difference in sensitivity of the sensor head to the object to be detected and the cover.

[0038] A certain embodiment may include, in addition to or instead of at least any one of the above-described Features 1 to 32, at least any one of the following Features 33 to 34. ·Feature 33: The object to be detected is a metal containing iron or a non-metal. ·Feature 34: The cover is a non-ferrous metal.

[0039] The electric working machine having at least Features 1-12, 33-34 can accurately detect the presence or position of the cover based on the difference in sensitivity of the sensor head to the object to be detected and the cover.

[0040] A certain embodiment may include, in addition to or instead of at least any one of the above-described Features 1 to 34, at least any one of the following Features 35 to 42. ·Feature 35: The object to be detected is integrally included in the cover. ·Feature 36: The cover and the object to be detected are metals. ·Feature 37: The cover is configured such that the object to be detected faces the sensor head when the cover is at least at a specific position within the specified region. · Feature 38: The cover is configured such that a peripheral member different from the object to be detected in the cover faces the sensor head as the cover deviates from the specified area. · Feature 39: The object to be detected has a first thickness. · Feature 40: The peripheral member has a second thickness. · Feature 41: The first thickness and the second thickness are lengths along the direction in which the object to be detected and the peripheral member face the sensor head. · Feature 42: The first thickness is different from the second thickness.

[0041] The electric working machine having at least Features 1 - 12, 35 - 42 can accurately detect the presence or position of the cover based on the difference in sensitivity of the sensor head to the object to be detected and the cover respectively.

[0042] A certain embodiment may include, in addition to or instead of at least any one of the above-described Features 1 to 42, the following Feature 43. · Feature 43: The first thickness is two times or more the second thickness, or one-half or less the second thickness.

[0043] The electric working machine having at least Features 1 - 12, 35 - 43 can increase the difference in sensitivity of the sensor head to the object to be detected and the cover respectively, thereby further improving the detection accuracy of the cover.

[0044] A certain embodiment may include, in addition to or instead of at least any one of the above-described Features 1 to 43, Features 35 - 38 and the following Feature 44. · Feature 44: The first area is different from the second area. The first area is the area of the portion of the detection object facing the sensor head when the surrounding member faces the detection object. The second area is the area of the portion of the surrounding member facing the sensor head when the surrounding member faces the sensor head.

[0045] The power-operated work machine having at least Features 1-12, 35-38, 44 can accurately detect the presence or position of the cover based on the difference in sensitivity of the sensor head to the detection object and the cover.

[0046] An embodiment may include, in addition to, or instead of, at least any one of Features 1 to 44 described above, the following Feature 45. · Feature 45: The first area is two times or more the second area, or one-half or less of the second area.

[0047] The power-operated work machine having at least Features 1-12, 35-38, 44-45 can increase the difference in sensitivity of the sensor head to the detection object and the cover, thereby further improving the detection accuracy of the cover.

[0048] An embodiment may include, in addition to, or instead of, at least any one of Features 1 to 45 described above, any one of the following Features 46 to 48. · Feature 46: Only one of the cover and the detection object is a conductor. · Feature 47: The cover and the detection object are different conductors from each other. · Feature 48: The cover and the detection object are the same conductor as each other and have different shapes from each other.

[0049] An electric device having at least Feature 1-12,46, Feature 1-12,47, or Feature 1-12,48 can properly detect the position of the cover according to the change in the detection signal, thereby properly detecting the position of the cover.

[0050] Regarding Feature 47, "different from each other" may mean, for example, different electrical characteristics. Specifically, for example, (i) one is a non-ferrous metal (e.g., magnesium) and the other is iron, (ii) different non-ferrous metals from each other (e.g., one is magnesium and the other is aluminum), or (iii) one is a metal and the other is a non-metal (e.g., graphite).

[0051] Regarding Feature 48, "the same as each other" may, contrary to Feature 47, mean, for example, the same electrical characteristics (e.g., both are magnesium). One embodiment may include, in addition to or instead of at least any one of the above-described Features 1 to 48, at least any one of the following Features 49 to 50. · Feature 49: The electric working machine is a circular saw. · Feature 50: The cutting tool includes a saw blade having a disc shape and provided with a plurality of teeth along the outer circumference.

[0052] An electric working machine having at least Features 1-12, 49-50 can accurately detect the position of the cover in a circular saw. Examples of the electric working machine include various on-site electric working machines configured to be used at work sites such as DIY, manufacturing, gardening, and construction. Specifically, electric tools for masonry, metalworking, and woodworking, gardening working machines, devices for preparing the work site environment. More specifically, electric circular saws, electric grinders, electric hand saws, electric reciprocating saws, electric jigsaws, electric cutters, electric chain saws, electric planers, electric hedge trimmers, electric lawn mowers, electric lawn clippers, and electric brush cutters.

[0053] Examples of the cutting tool include, for example, a disc-shaped saw blade used in a circular saw, a saw chain provided with a plurality of blades along the rotation direction, such as that used in a chainsaw, a nylon cutter used in, for example, a brush cutter, a disc-shaped grinding wheel used in, for example, a grinder, a blade provided with rod-shaped or long plate-shaped blades at both ends, and the like. Examples include a nylon cutter used in, for example, a brush cutter, a disc-shaped grinding wheel used in, for example, a grinder, a blade provided with rod-shaped or long plate-shaped blades at both ends, and the like.

[0054] In an embodiment, the control circuit may be integrated into a single electronic unit or a single electronic device or a single circuit board. In an embodiment, the control circuit may be a combination of two or more electronic circuits or two or more electronic units or two or more electronic devices provided individually within the electric working machine.

[0055] In an embodiment, the control circuit may include a microcomputer (or a microcontroller or a microprocessor), wiring logic, an application-specific integrated circuit (ASIC), an application-specific standard product (ASSP), a programmable logic device (such as a field-programmable gate array (FPGA)), discrete electronic components, and / or a combination thereof.

[0056] Examples of the motor include a brushed DC motor, a brushless DC motor, an AC motor, and a stepping motor. In an embodiment, any combination of the above features 1 to 50 may be used.

[0057] In an embodiment, any one of the above features 1 to 50 may be excluded. [2. Specific exemplary embodiments] Hereinafter, exemplary embodiments of the present disclosure will be described.

[0058] [2-1. First embodiment] (2-1-1) Configuration of the electric working machine With reference to FIGS. 1 to 5, the configuration of the electric working machine 1 according to the first embodiment will be described. For the sake of simplicity of explanation and ease of understanding, the front, rear, upper, lower, right, and left directions starting from the electric working machine 1 are defined as shown in FIG. 1 and the like.

[0059] The electric working machine 1 of this embodiment is in the form of a battery-driven circular saw. The circular saw can cut various workpieces such as wood, stone, plastic, metal, and concrete.

[0060] The electric working machine 1 includes a main body 2 and a base 10. The base 10 includes a base plate 11. The base plate 11 has a rectangular plate shape. The base plate 11 is placed on the upper surface of the workpiece when performing the cutting operation of the workpiece. The main body 2 is disposed on the upper surface side of the base plate 11.

[0061] The electric working machine 1 includes a saw blade 3. The saw blade 3 has a disc shape. The saw blade 3 includes a plurality of teeth provided along the outer circumference. The saw blade 3 is detachably attached to the right side surface of the main body 2. Specifically, as shown in FIGS. 1 to 3, the main body 2 includes a mounting portion 2a. The saw blade 3 is detachably mounted on the mounting portion 2a. The saw blade 3 is rotatable about a rotation axis 3a. The saw blade 3 is rotated by a motor 50 described later.

[0062] The base plate 11 includes a substantially rectangular opening 12 extending in the front-rear direction. The base plate 11 penetrates in the vertical direction at the opening 12. The saw blade 3 is disposed in a state of penetrating through this opening 12. Approximately the lower half of the saw blade 3 protrudes below the base plate 11 through the opening 12. A cover 30 described later is also disposed so as to penetrate through the opening 12.

[0063] The main body 2 includes a motor case 4. Inside this motor case 4, a motor 50 (see FIG. 15) is accommodated. The main body 2 is provided with a gear mechanism (not shown). The gear mechanism is mechanically connected to the motor 50 and the mounting portion 2a. The gear mechanism transmits the rotational force of the motor 50 to the mounting portion 2a. Thus, when the motor 50 rotates, the mounting portion 2a rotates together with the chisel blade 3 mounted on the mounting portion 2a.

[0064] The main body 2 is provided with a handle 5. The handle 5 is gripped by the user of the electric working machine 1. The main body 2 is provided with a trigger 6. The trigger 6 is provided at the end of the handle 5. The user can operate the trigger 6 while gripping the handle 5. The trigger 6 is configured to be movable when pressed. When the user presses the trigger 6 (pressing upward from below in FIG. 1), the trigger 6 moves from the initial position toward the handle 5 side (upward in FIG. 1). When the user releases the trigger 6, the trigger 6 returns to the initial position.

[0065] As shown in FIGS. 2 to 5, the main body 2 is configured such that the battery pack 200 can be detachably mounted. FIGS. 2 to 5 show a state in which the battery pack 200 is mounted. The battery pack 200 houses a battery 200a (see FIG. 15). The battery 200a can be any type of battery. The battery 200a of the first embodiment is in the form of a secondary battery.

[0066] The main body 2 includes a first main body shaft 7a (see FIG. 1) and a second main body shaft 8a (see FIG. 2). The first and second main body shafts 7a and 8a each have a substantially cylindrical shape extending in the front-rear direction and have an axis parallel to the front-rear direction. The axes of the first and second main body shafts 7a and 8a coincide with each other.

[0067] The main body portion 2 further includes a first slide shaft 7b (see FIG. 1) and a second slide shaft 8b (see FIG. 2). The first and second slide shafts 7b and 8b each have a substantially cylindrical shape extending in the front-rear direction and have an axis parallel to the front-rear direction. The axes of the first and second slide shafts 7b and 8b coincide with each other. The first slide shaft 7b is disposed at a predetermined distance to the left from the first main body shaft 7a. The second slide shaft 8b is disposed at the above-mentioned predetermined distance to the left from the second main body shaft 8a.

[0068] The base portion 10 includes a first support hole 14 (see FIG. 1) and a second support hole 16 (see FIG. 2). The first and second support holes 14 and 16 are fixed to the upper surface of the base plate 11. The first main body shaft 7a is rotatably inserted into the first support hole 14. The second main body shaft 8a is rotatably inserted into the second support hole 16. Thereby, the main body portion 2 can rotate about the first and second support holes 14 and 16 as rotation centers. That is, by default, the rotation plane of the chisel blade 3 is orthogonal to the bottom surface of the base plate 11, but by rotating the main body portion 2, the chisel blade 3 can be inclined with respect to the bottom surface of the base plate 11.

[0069] The base portion 10 includes a first support 13 (see FIGS. 1, 3, and 4) and a second support 15 (see FIGS. 2 and 4). The first and second supports 13 and 15 are fixed to the upper surface of the base plate 11. The first support 13 includes a substantially arc-shaped first slide hole 13a. The first slide hole 13a penetrates the first support 13 in the front-rear direction. The first slide shaft 7b is inserted into the first slide hole 13a and is movable along the first slide hole 13a. The second support 15 includes a substantially arc-shaped second slide hole 15a. The second slide hole 15a penetrates the second support 15 in the front-rear direction. The second slide shaft 8b is inserted into the second slide hole 15a and is movable along the second slide hole 15a.

[0070] As described above, the main body portion 2 is rotatable with respect to the base plate 11, but the rotation range It is restricted by the first and second slide holes 13a and 15a. In the present first embodiment, the main body 2 can rotate from the default position up to a maximum first inclination angle in the right direction and up to a maximum second inclination angle in the left direction. The first inclination angle is, for example, 45 degrees, and the second inclination angle is, for example, 5 degrees. FIG. 10 shows a state where the main body 2 is rotated by the first inclination angle in the right direction. FIG. 10 shows a state where the first slide shaft 7b has reached the end of the first slide hole 13a and further movement (i.e., rotation in the right direction exceeding 45 degrees) is restricted. The first inclination angle is an example of a predetermined rotation angle in the summary of the embodiment.

[0071] The main body 2 includes a chisel blade case 20. The chisel blade case 20 has the shape of an elongated and deep-grooved container that is open downward. The chisel blade case 20 includes a first case side plate 21, a second case side plate 22, and a third case side plate 23. The first case side plate 21 corresponds to the upper side surface of the chisel blade case 20. The first case side plate 21 is perpendicular or substantially perpendicular to the radial direction of the chisel blade 3 and is curved along the circumferential direction of the chisel blade 3. The second case side plate 22 corresponds to the right side surface of the chisel blade case 20. The third case side plate 23 corresponds to the left side surface of the chisel blade case 20. The chisel blade case 20 covers the peripheral edge in the range of approximately a semi-circle above the chisel blade 3.

[0072] The power working machine 1 includes a cover 30. The cover 30 has the shape of an elongated and deep-grooved container that is open upward. The cover 30 is configured to be able to cover the peripheral edge in the range of approximately a semi-circle below the chisel blade 3.

[0073] The cover 30 can rotate and move within a certain range in the closing direction or the opening direction along the circumferential direction of the chisel blade 3 around the rotation axis 3a, that is, along the rotation direction of the chisel blade 3. The closing direction and the opening direction are parallel to a plane perpendicular to the rotation axis 3a (see FIG. 3). The closing direction corresponds to the counterclockwise direction (in other words, the left-handed direction) in FIG. 3. The opening direction corresponds to the clockwise direction (in other words, the right-handed direction) in FIG. 3.

[0074] The structure of the cover 30 will be described with reference to FIGS. 6 and 7. The cover 30 is provided with a central hole 35. This central hole 35 (specifically, the rotating shaft 3a passing through the center thereof) serves as the rotation center of the cover 30.

[0075] The cover 30 includes a first cover side plate 31, a second cover side plate 32, and a third cover side plate 33. The first cover side plate 31 is configured to be spaced apart from the cutting edge of the saw blade 3 in the radial direction of the saw blade 3 (i.e., the direction perpendicular to the rotating shaft 3a).

[0076] The second cover side plate 32 is configured to be spaced apart from the first surface (right surface) of the saw blade 3 in the direction along the rotating shaft 3a. That is, the second cover side plate 32 directly faces the first surface of the saw blade 3.

[0077] The third cover side plate 33 is configured to be spaced apart from the second surface (left surface) of the saw blade 3 in the direction along the rotating shaft 3a. That is, the third cover side plate 33 directly faces the second surface of the saw blade 3.

[0078] The first cover side plate 31 includes a first cover outer surface 31a and a first cover inner surface 31b. The first cover outer surface 31a is a side surface that is exposed to the outside of the power working machine 1 and can be easily visually recognized by the user as a whole. Conversely, the first cover inner surface 31b is a side surface that cannot be easily visually recognized by the user or is difficult to visually recognize. The first cover inner surface 31b directly faces the cutting edge of the saw blade 3.

[0079] The second cover side plate 32 includes a second cover outer surface 32a and a second cover inner surface 32b. The second cover outer surface 32a is a side surface that is exposed to the outside of the power working machine 1 and can be easily visually recognized by the user as a whole. Conversely, the second cover inner surface 32b is a side surface that cannot be easily visually recognized by the user or is difficult to visually recognize and directly faces the first surface of the saw blade 3.

[0080] The third cover side plate 33 includes a third cover outer surface 33a and a third cover inner surface 33b. The third cover outer surface 33a is a side surface that is exposed to the outside of the power working machine 1 and can be easily visually recognized by the user as a whole. Conversely, the third cover inner surface 33b is a side surface that cannot be visually recognized by the user or is difficult to visually recognize, and directly faces the second surface of the saw blade 3.

[0081] A part of the outer periphery of the saw blade 3 is arranged so as to be present in the space surrounded by the first to third cover side plates 31 to 33 of the cover 30. Thereby, it is possible to prevent the area covered by the cover 30 among the teeth of the saw blade 3 from directly hitting the user.

[0082] The cover 30 is biased in the closing direction by an elastic body (not shown). Thereby, in the initial state, the cover 30 is in the fully closed position shown in FIGS. 1 to 3, 5, and 9. The initial state of the cover 30 means a state in which an external object such as a workpiece or a user does not touch the cover 30.

[0083] When an external force is applied to the cover 30 in the opening direction, the cover 30 moves in the opening direction against the biasing force of the elastic body. When referring to the movement of the cover 30 as "movement", it basically means "rotation".

[0084] When processing a workpiece, for example, with the front end side of the base plate 11 placed on the upper surface of the workpiece, the power working machine 1 is moved forward. When the power working machine 1 is moved forward, the saw blade 3 abuts against the workpiece and the cutting of the workpiece is started, and at the same time, the workpiece abuts against the front end of the cover 30, and the cover 30 receives an external force in the opening direction from the workpiece. Due to this external force, the cover 30 moves in the opening direction from the fully closed position.

[0085] The cover 30 includes a handle 34. The handle 34 is fixed to the end portion on the opening direction side of the second cover side plate 32. The user can manually rotate the cover 30 by pushing the handle 34 in the rotational direction.

[0086] Of the entire circumference of the saw blade 3, the region existing below the lower surface of the base plate 11 (hereinafter referred to as the "lower half circumference region") is, in this embodiment, mostly covered by the cover 30, but there is also a region not covered by the cover 30.

[0087] That is, as shown in FIG. 3, even when the cover 30 is in the fully closed position, a partial region on the front side of the lower half circumference region (hereinafter referred to as the "exposed region") is not covered by the cover 30. In other words, a range of a predetermined angle from the lower surface of the base plate 11 in the front of the lower half circumference region is not covered by the cover 30. The "predetermined angle" mentioned here means an angle along the rotation direction of the saw blade 3 centered on the rotation axis 3a, and this "predetermined angle" is hereinafter referred to as the "exposed angle". The exposed angle may be determined as appropriate. The exposed angle may be determined, for example, as any angle within 25 degrees to 45 degrees. The exposed angle of this embodiment is, for example, 25 degrees. In the following description, when referring to "angle" or "angle" regarding the rotation of the saw blade 3 or the rotation (i.e., opening and closing) of the cover 30, basically, similar to the exposed angle, it means an angle along the rotation direction of the saw blade 3 centered on the rotation axis 3a.

[0088] As shown in FIG. 3, when the cover 30 is in the fully closed position, the region of the lower half circumference region other than the exposed region and a region of a predetermined angle (for example about 10 degrees) further in the opening direction from the end on the opening side in the lower half circumference region are covered by the cover 30. The region of the outer peripheral edge of the saw blade 3 that is covered by the cover 30 when the cover 30 is in the fully closed position (i.e., the covered region in FIG. 3) is an example of the covered region in the summary of the embodiment.

[0089] The cover 30 is movable within a predetermined movable range from the fully closed position to the fully open position. FIG. 8 schematically shows the change in the position of the cover 30. The left side in FIG. 8 shows the state where the cover 30 is in the fully closed position. The fully closed position is the position on the most closed direction side among the regions where the cover 30 is considered to be in the closed position (i.e., closed). The fully closed position is also referred to as the first closed position.

[0090] The center in FIG. 8 shows a state where the cover 30 is in the closed position, particularly in the second closed position. The second closed position is the position on the most open side among the closed positions. The second closed position is a position rotated by a predetermined closed region angle in the opening direction from the first closed position. The closed region angle may be determined as appropriate. In this embodiment, the closed region angle is, for example, 30 degrees. In this embodiment, the range between the first closed position and the second closed position is regarded as the closed position, that is, being closed. Note that the range covered by the cover 30 when the cover 30 is moved to the second closed position within the above-described covering region is an example of a predetermined range in the summary of the embodiment. The first closed position is an example of the first specified position in the summary of the embodiment, and the second closed position is an example of the second specified position in the summary of the embodiment.

[0091] The position on the opening direction side rather than the second closed position is the open position. The right side in FIG. 8 shows a state where the cover 30 is in the fully open position. The fully open position is the position on the most open side among the open positions.

[0092] In the first embodiment, as described above, the main body 2 can be inclined to the right with respect to the base plate 11. When the main body 2 is inclined to the right, the handle 34 of the cover 30 abuts against the base plate 11. As a result, the cover 30 moves in the opening direction. When the main body 2 is inclined by the maximum angle to the right (the first inclination angle described above. In this embodiment, it is 45 degrees.), the cover 30 is moved in the opening direction by a predetermined opening angle during inclination from the fully closed position by the base plate 11.

[0093] In this embodiment, the opening angle during inclination is, for example, 30 degrees. The above-described closed region angle is set to be equal to or greater than this opening angle during inclination (as an example, 30 degrees as described above). That is, in this embodiment, even if the cover 30 is opened by the opening angle during inclination due to the inclination of the main body 2, the cover 30 is regarded as being in the closed position.

[0094] The angle of the movable range from the fully closed position to the fully open position (hereinafter referred to as "movable angle") may be determined as appropriate. The movable angle may be determined to be any angle, for example, within the range of 130 degrees to 150 degrees. The movable angle and the exposure angle may be determined such that, for example, the sum of the two is 180 degrees or less. In the present embodiment, although it is merely an example, the exposure angle is 25 degrees as described above and the movable angle is 150 degrees.

[0095] In the first embodiment, the material of the cover 30 is non-metal (specifically, non-conductor). The cover 30 of the first embodiment contains resin. The main component of the cover 30 may be resin, or the entire cover 30 may be composed of resin. The cover 30 may be in the form of a resin molded product formed, for example, by integrally molding resin. Note that the handle 34 is attached to the cover 30 with screws. However, the handle 34 may also be integrally molded with the cover 30.

[0096] As shown in FIGS. 2, 3, 5, 6, and 9 (specifically FIGS. 6 and 7), the electric working machine 1 includes a detection object 36. The detection object 36 is an object to be detected by a conductor sensor 40 described later. The detection object 36 is used to determine whether the cover 30 is in the closed position. The detection object 36 is provided on the cover 30. More specifically, in the first embodiment, the detection object 36 is fixed on the outer surface 31a of the first cover.

[0097] The detection object 36 has the form of a rectangular thin plate, thin film, or foil. The detection object 36 may be fixed to the outer surface 31a of the first cover in any manner. The detection object 36 may be fixed to the outer surface 31a of the first cover by, for example, an adhesive or other member.

[0098] In the following description, when simply referring to the "length" of the detection object 36, it means the length in the opening and closing direction, when referring to the "width", it means the length in the direction orthogonal to the opening and closing direction (i.e., the left-right direction), and when referring to the "thickness", it means the length in the direction orthogonal to the surface of the detection object 36.

[0099] The object to be detected 36 is a conductor. The object to be detected 36 may be any conductor. The object to be detected 36 is one that generates eddy currents when receiving an alternating magnetic field from the conductor sensor 40 described later. In other words, it may be any conductor as long as it is electrically and / or magnetically affected by the alternating magnetic field from the conductor sensor 40. The object to be detected 36 may contain metal. Alternatively, the object to be detected 36 may contain a non-metallic conductor (e.g., graphite).

[0100] In this specification, when referring to "including a conductor", "including metal", "including iron", "including magnesium", "including non-metal", "including non-ferrous metal", "including resin", etc., basically it means that the object is included as a main component or the object only is included (i.e., composed of the object). However, it may also include that the object is partially included. The same applies to each of the following embodiments after the second embodiment described later.

[0101] In this embodiment, the object to be detected 36 is metal. The object to be detected 36 may contain any metal. In this first embodiment, the object to be detected 36 contains non-ferrous metal and does not contain iron. The non-ferrous metal may be, for example, copper or aluminum.

[0102] One of the reasons for excluding iron from the object to be detected 36 in the first embodiment is the ease of detecting the object to be detected 36 by the conductor sensor 40. The oscillation circuit 45 (see FIG. 13) described later reacts more sensitively to non-ferrous metal than to iron (i.e., the change in the oscillation frequency is large). Therefore, in this first embodiment, the object to be detected 36 is a non-ferrous metal other than iron. However, of course, the object to be detected 36 may contain iron.

[0103] The thickness and width of the object to be detected 36 may be appropriately determined so that the conductor sensor 40 can properly detect the open / closed state of the cover 30. The thickness of the object to be detected 36 may be, for example, 0.1 mm or more.

[0104] The length and the arrangement position of the object 36 to be detected are determined in consideration of the position of a sensor head 42 (see FIG. 11) described later in the conductor sensor 40 and so that the conductor sensor 40 determines that the cover 30 is in the closed position when the cover 30 is in the closed position. Specifically, when the cover 30 is in the closed position, the sensor head 42 faces the object 36 to be detected, and when the cover 30 is in the open position, the sensor head 42 does not face the object 36 to be detected. Note that even if the sensor head 42 does not face the object 36 to be detected, it may be determined that the cover is in the closed position if the distance between the two is within a predetermined range. Conversely, even if the sensor head 42 faces the object 36 to be detected, it may be determined that the cover is in the open position if the facing area is equal to or less than a predetermined amount.

[0105] As shown in FIGS. 3, 5, and 9, the electric working machine 1 includes the aforementioned conductor sensor 40. The conductor sensor 40 is arranged so as to be separated from the cover 30 in the radial direction of the rotation radius of the cover 30 (that is, with a space therebetween) and so that the sensor head 42 faces the cover 30 in the radial direction of the rotation radius. The conductor sensor 40 is further arranged so as to be separated from the object 36 to be detected in the radial direction of the rotation radius. Specifically, in the present first embodiment, the conductor sensor 40 is adjacent to the cover 30 and the object 36 to be detected without contact.

[0106] The conductor sensor 40 can detect a conductor without contact, without contacting the conductor. When a conductor approaches the conductor sensor 40, the electrical characteristics of the conductor sensor 40 change according to the distance between the conductor sensor 40 and the conductor. The conductor sensor 40 can detect the presence or absence of a conductor and / or the distance between the conductor sensor 40 and the conductor based on the change in the electrical characteristics.

[0107] As shown in FIG. 11, the conductor sensor 40 of the present first embodiment includes a sensor substrate 41. The sensor substrate 41 includes a first surface 41a and a second surface 41b. The conductor sensor 40 further includes the aforementioned sensor head 42. The sensor head 42 is mounted on the first surface 41a. The sensor head 42 outputs an electrical signal corresponding to the distance between the sensor head 42 and the object 36 to be detected.

[0108] The conductor sensor 40 of this embodiment is inductive. That is, as shown in FIG. 11, the sensor head 42 includes a coil L1. The current flowing through the coil L1 corresponds to the aforementioned electrical signal. The coil L1 of this embodiment is in the form of an air-core coil. The coil L1 of this embodiment is in the form of printed wiring formed on the first surface 41a. However, the coil L1 may have a core material.

[0109] As will be described later, the coil L1 is part of an oscillation circuit 45 (see FIG. 13), and an alternating current flows through the coil L1. When an alternating current flows through the coil L1, an alternating magnetic field is generated from the coil L1. When the magnetic flux of the alternating magnetic field penetrates the detection object 36, eddy currents are generated in the detection object 36. The eddy currents are generated in a direction that obstructs the change in the magnetic flux of the alternating magnetic field. In response to the generation of the eddy currents, the electrical characteristics of the oscillation circuit 45 change. Specifically, the oscillation frequency of the oscillation circuit 45 changes.

[0110] As shown in FIG. 11, the conductor sensor 40 further includes a sensor circuit 43. The sensor circuit 43 is mounted on the first surface 41a. The sensor circuit 43 generates and outputs detection information based on the electrical signal from the sensor head 42. The detection information of this embodiment indicates whether the detection object 36 is close to the sensor head 42, that is, whether the cover 30 is in the closed position or the open position.

[0111] The sensor circuit 43 may be mounted on the second surface 41b, or may be mounted on both the first surface 41a and the second surface 41b. Further, the sensor substrate 41 may be in the form of a multilayer substrate including an internal conductor layer. In this case, part or all of the sensor circuit 43 may be arranged in the internal conductor layer. When the sensor circuit 43 is arranged on two or more of the first surface 41a, the second surface 41b, and the internal conductor layer, the area of the sensor substrate 41 can be reduced compared to the case where it is arranged on only one of them.

[0112] As shown in FIG. 12, in the present embodiment, the conductor sensor 40 is attached to the first case side plate 21 such that at least a part (or all) of the sensor head 42 protrudes from the lower end of the chisel edge case 20. FIG. 12 schematically shows a state where the cover 30 is in the fully closed position.

[0113] The conductor sensor 40 is provided such that the mounting surface of the coil L1 (hereinafter referred to as the “coil mounting surface”; a part of the first surface 41a in this example) intersects with the direction perpendicular to the rotation axis 3a, that is, so as to face the detection object 36 in the radial direction when viewed from the rotation axis 3a. In the present embodiment, the direction perpendicular to the rotation axis 3a is perpendicular or substantially perpendicular to the mounting surface of the coil L1. The size of the coil mounting surface, that is, the first width W1 and the second width W2 in the present first embodiment may be determined in any manner. The first width W1 may be the same as or different from the second width W2. In the present first embodiment, the first width W1 is the same as the second width W2 and is, for example, 20 mm or in the vicinity thereof.

[0114] Note that the size of the coil mounting surface depends on the size of the detection object 36 (for example, width and / or thickness). The size of the coil mounting surface may be determined within a range where the opening / closing state of the cover 30 can be appropriately detected in consideration of the size of the detection object 36.

[0115] As shown in FIG. 12, when the cover 30 is in the fully closed position, the sensor head 42 (specifically, the coil mounting surface) is at least partially opposed to the detection object 36. Here, the “opposed” means opposed in the direction perpendicular to the first surface 41a.

[0116] Although not shown, even when the cover 30 is moved from the fully closed position to the second closed position (see the center of FIG. 8), the sensor head 42 is opposed to the detection object 36. When the cover 30 is further opened from the second closed position, the sensor head 42 no longer faces the detection object 36, and the distance between the sensor head 42 and the detection object 36 increases.

[0117] The electrical characteristics of the sensor head 42 change according to the distance between the sensor head 42 and the object 36 to be detected, and / or according to the area of the region of the sensor head 42 facing the object 36 to be detected. The electrical signal from the sensor head 42 changes according to the change in the electrical characteristics.

[0118] The distance in the facing direction between the sensor head 42 and the object 36 to be detected is hereinafter referred to as the "detection facing distance X0". The detection facing distance X0 may be determined to be a value such that the conductor sensor 40 can appropriately determine the open / closed state of the cover 30. The detection facing distance X0 may be determined to be any value within a range of, for example, 1 mm or more and less than 15 mm. In the first embodiment, the detection facing distance X0 is, for example, 5 mm.

[0119] (2-1-2) Electrical configuration of the conductor sensor A more detailed electrical configuration of the conductor sensor 40 will be described with reference to FIG. 13. As shown in FIG. 13, the conductor sensor 40 is connected to the first connector 66. A control voltage Vcc is input to the conductor sensor 40 from a second control circuit 52 (see FIG. 15) or a sensor setting device 71 (see FIG. 16) described later via the first connector 66. The control voltage Vcc is in the form of a DC voltage. The conductor sensor 40 can further communicate with the second control circuit 52 or the sensor setting device 71 via the first connector 66.

[0120] As shown in FIG. 13, the conductor sensor 40 includes an oscillation circuit 45. The oscillation circuit 45 of the present embodiment is in the form of a self-excited oscillation circuit, and more specifically, in the form of a Colpitts oscillation circuit. Specifically, the oscillation circuit 45 includes a resonance circuit. The resonance circuit includes the coil L1, the first capacitor C1, and the second capacitor C2 described above.

[0121] The first end of coil L1 is connected to the first end of first capacitor C1. The second end of coil L1 is connected to the first end of second capacitor C2. The second ends of first capacitor C1 and second capacitor C2 are connected to ground. In this embodiment, first capacitor C1 and / or second capacitor C2 are in the form of film capacitors.

[0122] Oscillation circuit 45 further includes a first resistor R1, a second resistor R2, and a transistor Tr1. The first ends of first resistor R1 and second resistor R2 are applied with a control voltage Vcc. The second end of first resistor R1 is connected to the first end of coil L1. The second end of second resistor R2 is connected to the second end of coil L1.

[0123] In this embodiment, transistor Tr1 is in the form of an n-channel type FET (field effect transistor). The gate of transistor Tr1 is connected to the first end of coil L1. The drain of transistor Tr1 is connected to the second end of coil L1. The source of transistor Tr1 is connected to ground.

[0124] In oscillation circuit 45 configured as described above, when control voltage Vcc is applied, the resonance circuit self-excites at an oscillation frequency that is the same as or near the resonance frequency of the resonance circuit, and outputs an oscillation signal P1 having that oscillation frequency. Oscillation signal P1 is in a sine wave form as illustrated in FIG. 14.

[0125] The oscillation frequency changes according to the position of the object to be detected 36. As the object to be detected 36 approaches the sensor head 42, the impedance of the sensor head 42 decreases due to the influence of the eddy current generated in the object to be detected 36, and thereby the oscillation frequency increases. That is, the oscillation frequency when cover 30 is in the closed state is higher than the oscillation frequency when cover 30 is in the open state.

[0126] As shown in FIG. 13, the conductor sensor 40 includes a conversion circuit 46. The conversion circuit 46 receives an oscillation signal P1 from an oscillation circuit 45. The conversion circuit 46 converts the input oscillation signal P1 into a rectangular first pulse signal P3 as illustrated in FIG. 14.

[0127] The conversion circuit 46 includes a level shift circuit 46a. The level shift circuit 46a shifts the voltage value of the DC component included in the oscillation signal P1 to a value within a range that can be appropriately processed by a subsequent comparison circuit 46b.

[0128] The level shift circuit 46a includes a third resistor R3, a fourth resistor R4, and a third capacitor C3. A first terminal of the third capacitor C3 is connected to the oscillation circuit 45, and the oscillation signal P1 is input from the oscillation circuit 45. A control voltage Vcc is applied to a first terminal of the third resistor R3. A second terminal of the third resistor R3 is connected to a first terminal of the fourth resistor R4 and a second terminal of the third capacitor C3. A second terminal of the fourth resistor R4 is connected to ground.

[0129] The third capacitor C3 functions as a so-called coupling capacitor. That is, the third capacitor C3 removes the DC voltage included in the oscillation signal P1. The third resistor R3 and the fourth resistor R4 superimpose a reference voltage of a predetermined level on the oscillation signal P1 from which the DC voltage has been removed. The reference voltage is the voltage at the second terminal of the third resistor R3. The control voltage Vcc is divided by the third resistor R3 and the fourth resistor R4. The divided voltage is superimposed as the reference voltage on the AC signal from the third capacitor C3. The level shift circuit 46a outputs a signal P2 in which the oscillation signal P1 has been level-shifted in this way. FIG. 14 shows an example of the level-shifted signal P2.

[0130] The resistance value of the third resistor R3 and the resistance value of the fourth resistor R4 may be determined in any way within a range in which the signal P2 can be appropriately processed by the subsequent comparison circuit 46b. For example, the resistance value of the third resistor R3 may be equal to the resistance value of the fourth resistor R4. In this case, the reference voltage is 1 / 2 of the control voltage Vcc.

[0131] The conversion circuit 46 includes the aforementioned comparison circuit 46b. The comparison circuit 46b receives the signal P2 from the level shift circuit 46a and converts the signal P2 into a rectangular first pulse signal P3. The comparison circuit 46b includes a comparator 46c, a fifth resistor R5, a sixth resistor R6, and a fourth capacitor C4.

[0132] A control voltage Vcc is applied to the first end of the fifth resistor R5. The second end of the fifth resistor R5 is connected to the first end of the sixth resistor R6 and to the inverting input terminal of the comparator 46c. Therefore, the voltage at the second end of the fifth resistor R5 (hereinafter referred to as the "threshold voltage") is input to the inverting input terminal of the comparator 46c. The second end of the sixth resistor R6 is connected to the ground.

[0133] The non-inverting input terminal of the comparator 46c receives the level-shifted signal P2 from the level shift circuit 46a. The positive power supply terminal of the comparator 46c is connected to the first end of the fourth capacitor C4 and a control voltage Vcc is applied thereto. The negative power supply terminal of the comparator 46c is connected to the second end of the fourth capacitor C4 and the ground.

[0134] The threshold voltage has a magnitude different from the reference voltage in consideration of the input offset voltage of the comparator 46c. Specifically, in this embodiment, the threshold voltage is slightly lower than the reference voltage. When the input signal P2 is lower than the threshold voltage, the comparator 46c outputs a Low-level first pulse signal P3, and when the input signal P2 is equal to or higher than the threshold voltage, the comparator 46c outputs a High-level first pulse signal P3 (see FIG. 14).

[0135] As shown in FIG. 13, the conductor sensor 40 includes a frequency division circuit 47. The frequency division circuit 47 receives a first pulse signal P3 from the conversion circuit 46. The frequency division circuit 47 divides the input first pulse signal P3, that is, converts the frequency of the first pulse signal P3 to 1 / n (n is a natural number). The signal after frequency division is hereinafter referred to as the "second pulse signal P4". The frequency division ratio 1 / n can be determined in any way. In the present embodiment, the frequency division ratio 1 / n is determined according to the resolution of the second pulse signal P4 in the subsequent first control circuit 48. That is, the frequency division ratio 1 / n is set so that the first control circuit 48 can appropriately determine the state of the cover 30 based on the second pulse signal P4. For example, the frequency division ratio 1 / n may be 1 / 16. FIG. 14 illustrates the second pulse signal P4 obtained by frequency division with the frequency division ratio 1 / n.

[0136] As shown in FIG. 13, the conductor sensor 40 includes a first control circuit 48. The first control circuit 48 of the present embodiment includes a microcomputer including a CPU 48a and a memory 48b. The memory 48b includes semiconductor memories such as ROM, RAM, NVRAM, and flash memory, for example. By executing the programs stored in the first control circuit 48 (specifically, the CPU 48a) and the memory 48b, various functions are realized.

[0137] The first control circuit 48 receives the second pulse signal P4 from the frequency division circuit 47. The first control circuit 48 determines whether the cover 30 is in the closed position or the open position based on the pulse width Tx (or period) of the input second pulse signal P4. Specifically, the first control circuit 48 determines that the cover 30 is in the open position when the pulse width Tx is greater than the threshold value Tavg, that is, when the oscillation frequency is relatively low. On the other hand, the first control circuit 48 determines that the cover 30 is in the closed position when the pulse width Tx is less than or equal to the threshold value Tavg, that is, when the oscillation frequency is relatively high.

[0138] The first control circuit 48 outputs detection information indicating the determination result to the second control circuit 52 via the first connector 66. The detection information includes a closed response and an open response, which will be described later. The closed response is output when it is determined that the cover 30 is in the closed position. The open response is output when it is determined that the cover 30 is in the open position. Details of such determination will be described later with reference to FIG. 22. for reference.

[0139] Some or all of the various functions realized by the first control circuit 48 may be achieved by executing a program (i.e., by software processing), or may be achieved by one or more hardware components. For example, instead of or in addition to a microcomputer, the first control circuit 48 may include a logic circuit including a plurality of electronic components, may include an application-specific integrated circuit such as an ASIC and / or an ASSP, or may include a programmable logic device such as an FPGA capable of constructing any logic circuit.

[0140] Note that the frequency division circuit 47 and the first control circuit 48 are each configured to be supplied with the control voltage Vcc. The frequency division circuit 47 and the first control circuit 48 operate while being supplied with the control voltage Vcc.

[0141] (2-1-3) Electrical Configuration of the Electric Working Machine Referring to FIG. 15, the electrical configuration of the electric working machine 1 will be described. The electric working machine 1 includes the motor 50 described above. The motor 50 may be in any form. As an example, the motor 50 of the first embodiment is in the form of a brushless motor.

[0142] The electric working machine 1 includes a motor drive circuit 51. The motor drive circuit 51 is electrically connected to the positive electrode of the battery 200a and receives battery power from the battery 200a. The motor drive circuit 51 converts the battery power into three-phase power according to the input motor control signal and outputs the three-phase power to the motor 50. The motor 50 is driven by this three-phase power. The motor drive circuit 51 of the present first embodiment is, for example, in the form of a three-phase full-bridge circuit.

[0143] The electric working machine 1 includes a second control circuit 52. The second control circuit 52 of the present first embodiment includes a microcomputer including a CPU 52a and a memory 52b. The memory 52b includes, for example, semiconductor memories such as ROM, RAM, NVRAM, and flash memory. The second control circuit 52 (specifically, the CPU 52a) realizes various functions by executing the programs stored in the memory 52b. Further, the second control circuit 52 stores the temporary data generated according to various functions in the memory 52b.

[0144] Some or all of the various functions realized by the second control circuit 52 may be achieved by executing programs (that is, by software processing), or may be achieved by one or a plurality of hardware. For example, instead of or in addition to the microcomputer, the second control circuit 52 may include a logic circuit including a plurality of electronic components, may include an application-specific integrated circuit such as ASIC and / or ASSP, or may include a programmable logic device such as FPGA capable of constructing an arbitrary logic circuit.

[0145] The electric working machine 1 includes a rotation sensor 53. The rotation sensor 53 outputs a signal according to the rotation position of the motor 50 (specifically, the rotation position of a rotor, not shown in detail). The rotation sensor 53 of the present first embodiment includes three Hall sensors. The three Hall sensors output three detection signals having different phases from each other according to the rotation position of the motor 50.

[0146] The electric working machine 1 includes a position detection circuit 54. The position detection circuit 54 receives three detection signals from the rotation sensor 53. The position detection circuit 54 detects the position of the motor 50 based on those detection signals, and outputs a position detection signal indicating the detected position to the second control circuit 52.

[0147] The electric working machine 1 includes a trigger switch 6a. The trigger switch 6a is connected to the trigger 6 and is turned on or off accordingly. When the trigger 6 is in the initial position, the trigger switch 6a is off. When the trigger 6 is pushed and moved from the initial position, the trigger switch 6a is on. The trigger switch 6a outputs a trigger signal indicating the state (i.e., on or off) of the trigger switch 6a to the second control circuit 52.

[0148] The electric working machine 1 includes a mode button 56. The mode button 56 is turned on or off by the user to set the operation mode of the motor 50. The mode button 56 outputs a mode button signal indicating the state (i.e., on or off) of the mode button 56 to the second control circuit 52.

[0149] The electric working machine 1 includes a notification unit 57. The notification unit 57 is controlled by the second control circuit 52. The notification unit 57 is provided to convey various information to the user. The various information includes, for example, the operation state of the electric working machine 1, the fact that the electric working machine 1 is in a specific state (e.g., an abnormal state), and so on.

[0150] The notification unit 57 of the present first embodiment includes a display unit 57a. The display unit 57a includes a display device such as a liquid crystal display. The display unit 57a visually provides various information to the user. The notification unit 57 includes a sound generation unit 57b. The sound generation unit 57b is configured to generate various sounds. The sound generation unit 57b aurally provides various information to the user.

[0151] ​The electric working machine 1 includes a power supply circuit 55. The power supply circuit 55 is electrically connected to the positive electrode of the battery 200a, and battery power is input from the battery 200a. The power supply circuit 55 generates the aforementioned control voltage Vcc from the battery power and outputs the control voltage Vcc to each part within the electric working machine 1. The second control circuit 52 is activated upon receiving the control voltage Vcc.

[0152] The electric working machine 1 includes the aforementioned first connector 66 and a second connector 61. As shown in FIG. 13, the first connector 66 is connected to the conductor sensor 40 via a cable. The second connector 61 is detachably attached to the first connector 66.

[0153] The second connector 61 is connected to the first end of the first switch 62, the ground line of the electric working machine 1, and the second control circuit 52. The ground line of the conductor sensor 40 is connected to the ground line of the electric working machine 1 via the first and second connectors 66, 61. Detection information from the conductor sensor 40 is input to the second control circuit 52 via the first and second connectors 66, 61. The second control circuit 52 can communicate with the first control circuit 48 of the conductor sensor 40 via the first and second connectors 66, 61. The second end of the first switch 62 has the control voltage Vcc applied thereto.

[0154] The first switch 62 is turned on or off by the second control circuit 52. When the first switch 62 is turned on, the control voltage Vcc is supplied to the conductor sensor 40 via the first switch 62, the first and second connectors 66, 61. This control voltage Vcc supplied to the conductor sensor 40 via the first switch 62 is hereinafter referred to as "sensor power".

[0155] When the trigger switch 6a is turned on, the second control circuit 52 outputs a motor control signal for rotating the motor 50 to the motor drive circuit 51 based on the position detection signal according to the set operation mode. Basically, the motor 50 is continuously driven while the trigger switch 6a is on. However, depending on the state of the electric working machine 1, the motor 50 may not be driven even when the trigger switch 6a is on, or the output may be restricted (for example, the speed and / or torque are restricted) and driven compared to the normal state.

[0156] The second control circuit 52 recognizes the open / closed state of the cover 30 based on the detection information from the conductor sensor 40. When the cover 30 is in the open position in a specific situation (for example, when the trigger switch 6a is turned on), the motor 50 is stopped or the output is restricted.

[0157] Also, the second control circuit 52 can set the threshold value Tavg for the conductor sensor 40 through communication with the conductor sensor 40. (2-1-4) Setting of Threshold Value Tavg for Conductor Sensor A predetermined value may be set in the conductor sensor 40 in advance as the threshold value Tavg. However, there are individual differences in the detection sensitivity of the conductor sensor 40. Therefore, preferably, an appropriate threshold value Tavg considering the characteristics specific to the used conductor sensor 40 is set. In the first embodiment, the threshold value Tavg can be set for the conductor sensor 40 by the following two methods. One is the setting by a sensor setting system 70 (see FIG. 16) separate from the electric working machine 1, and the other is the setting by the second control circuit 52 of the electric working machine 1. The following will be described in order.

[0158] (2-1-4-1) Setting of Threshold Value Tavg by Sensor Setting System The sensor setting system 70 shown in FIG. 16 is configured to calculate the threshold value Tavg of the conductor sensor 40 and set it to the conductor sensor 40.

[0159] The sensor setting system 70 includes a sensor setting device 71, an input switch 72, a completion notification unit 73, an error notification unit 74, a third connector 75, and a second switch 76. The third connector 75 is detachable from the first connector 66. The third connector 75 and the second switch 76 have the same configuration as the second connector 61 and the first switch 62 of the electric working machine 1. A control voltage Vcc is applied to the second terminal of the second switch 76 from a power supply circuit (not shown). The second switch 76 is turned on or off by the sensor setting device 71. The sensor setting device 71 can communicate with the conductor sensor 40 via the first and third connectors 66 and 75.

[0160] The sensor setting system 70 includes a linear movement device 80. The linear movement device 80 includes a support base 81. The support base 81 includes a chassis 81a and side walls 81b. The side walls 81b are erected from the ends of the chassis 81a. The surface of the side walls 81b is configured to be able to fix the conductor sensor 40.

[0161] A linear table 82, a motor 83, and a driver 84 are provided on the chassis 81a. The linear table 82 is movable in a direction perpendicular to the surface of the side walls 81b. The motor 83 moves the linear table 82. The driver 84 supplies power for rotating the motor 83 to the motor 83. The driver 84 is controlled by the sensor setting device 71.

[0162] The sensor setting device 71 includes a microcomputer 71a. The setting of the threshold value Tavg by the sensor setting device 71 is performed by the software processing of the microcomputer 71a. Specifically, the microcomputer 71a is configured to be able to execute the threshold value setting process of FIG. 17. With reference to FIG. 17, the threshold value setting process will be described.

[0163] When the sensor setting system 70 sets the threshold value Tavg, the user first sets the conductor sensor 40 and the conductor plate 500 on the linear moving device 80. As described above, the conductor sensor 40 is set on the surface of the side wall 81b. The conductor plate 500 can be set on the linear table 82. The conductor plate 500 may be the detection object 36 actually attached to the cover 30, or may be a conductor that is the same as or similar to the actual detection object 36. The length, width, and / or thickness of the conductor plate 500 may be different from those of the detection object 36. The length, width, and thickness of the conductor plate 500 are set to an appropriate threshold value Tavg for the conductor sensor 40 It may be determined in any way as long as possible.

[0164] When the conductor sensor 40 and the conductor plate 500 are properly set on the linear moving device 80, the sensor head 42 of the conductor sensor 40 faces the conductor plate 500. At this time, the coil mounting surface is parallel or substantially parallel to the conductor plate 500.

[0165] The user sets the conductor sensor 40 and the conductor plate 500 in this way, and activates the sensor setting device 71. Then, the input switch 72 is operated (for example, pressed). When the input switch 72 is operated, the input switch 72 outputs a setting completion signal to the sensor setting device 71.

[0166] When the sensor setting device 71 (specifically, the microcomputer 71a) is activated, it executes the threshold setting process of FIG. 17. When the microcomputer 71a starts the threshold setting process, in S10, it determines whether a setting completion signal has been input from the input switch 72. If a setting completion signal has been input, this process proceeds to S20.

[0167] In S20, the microcomputer 71a starts supplying sensor power to the conductor sensor 40. Specifically, it turns on the second switch 76. In S30, the microcomputer 71a communicates with the conductor sensor 40 (specifically, with the first control circuit 48). The communication in S30 includes transmitting a setting command to the conductor sensor 40 and checking the completion flag in the conductor sensor 40. The setting command notifies the conductor sensor 40 that a series of processes for setting the threshold value Tavg is to be started.

[0168] In S40, the microcomputer 71a determines whether the completion flag is set in the conductor sensor 40. That the completion flag is set means that the threshold value Tavg has already been set. That the completion flag is not set means that the threshold value Tavg has not yet been set.

[0169] If the completion flag is not set, this process proceeds to S50. If the completion flag is set, this process proceeds to S250. In S250, the microcomputer 71a communicates with the conductor sensor 40. Specifically, it instructs the conductor sensor 40 to erase the completion flag.

[0170] In S260, the microcomputer 71a starts timing with a timer. In S270, the microcomputer 71a determines whether it has received a completion response from the conductor sensor 40. The completion response is transmitted by the first control circuit 48 that has received the erase command in S250. If the completion response has not been received, this process proceeds to S290. In S290, it is determined whether the timer value is equal to or greater than the first timing threshold value Tth1. If the timer value is less than the first timing threshold value Tth1, this process proceeds to S270. If the timer value is equal to or greater than the first timing threshold value Tth1, this process proceeds to S300.

[0171] In S300, the microcomputer 71a stops supplying sensor power to the conductor sensor 40. Specifically, it turns off the second switch 76. In S310, the microcomputer 71a activates the error notification unit 74 to perform error notification. That is, it notifies the user that the threshold value Tavg cannot be set normally. The error notification can be performed in any way. For example, it may display a message for notification, or it may notify by sound.

[0172] In S270, when the microcomputer 71a receives a completion response from the conductor sensor 40, it stops the timer in S280 and proceeds to S50. In S50, the microcomputer 71a moves the linear table 82 to the first position via the driver 84. The first position is the position where the distance X between the sensor head 42 and the conductor plate 500 is X1. The distance X1 is assumed based on the detection opposing distance X0 when the cover 30 is in the fully closed position in the electrical device 1. The distance X1 may be, for example, greater than 1 mm and less than 15 mm. In this first embodiment, the distance X1 is greater than the actual detection opposing distance X0. As described above, the detection opposing distance X0 in this first embodiment is 5 mm. Therefore, in this first embodiment, the distance X1 may be, for example, 6 mm.

[0173] In S60, the microcomputer 71a communicates with the conductor sensor 40. Specifically, it commands the conductor sensor 40 to measure the pulse width of the second pulse signal P4 (hereinafter referred to as "pulse width T1" at this time), save the measured pulse width T1, and transmit the pulse width T1 to the sensor setting device 71. Thereby, the microcomputer 71a acquires the pulse width T1.

[0174] In S70, the microcomputer 71a starts timing with a timer. In S80, the microcomputer 71a determines whether it has received a completion response from the conductor sensor 40. The first control circuit 48 is configured to transmit a completion response after completing the processing for the command in S60.

[0175] If a completion response has not been received, this process proceeds to S90. In S90, it is determined whether the timer value is greater than or equal to the first timing threshold Tth1. If the timer value is less than the first timing threshold Tth1, this process proceeds to S80. If the timer value is greater than or equal to the first timing threshold Tth1, this process proceeds to S320. The processing after S320 is the same as the processing after S300.

[0176] In S80, if a completion response is received from the conductor sensor 40, the microcomputer 71a stops the timer in S100 (see FIG. 18) and proceeds to S110. In S110, the microcomputer 71a moves the linear table 82 to the second position via the driver 84. The second position is the position where the distance X becomes X2. The distance X2 is greater than the actual detection facing distance X0. The distance X2 may be, for example, 15 mm or more. In this first embodiment, the distance X2 is, for example, 15 mm.

[0177] In S120, the microcomputer 71a communicates with the conductor sensor 40. Specifically, the microcomputer 71a commands the conductor sensor 40 to measure the pulse width of the second pulse signal P4 (hereinafter referred to as "pulse width T2" at this time), save the measured pulse width T2, and transmit the pulse width T2 to the sensor setting device 71. Thereby, the microcomputer 71a acquires the pulse width T2.

[0178] In S130, the microcomputer 71a calculates the threshold value Tavg based on the acquired pulse widths T1 and T2. The threshold value Tavg can be calculated in any way. For example, any value between T1 and T2 may be calculated as the threshold value Tavg. Alternatively, T1 and T2 may be substituted into a predetermined arithmetic expression for threshold calculation for calculation. In this first embodiment, for example, the average value of T1 and T2 is calculated as the threshold value Tavg.

[0179] When the microcomputer 71a calculates the threshold value Tavg, it communicates in S140. Specifically, the calculated threshold value Tavg is transmitted to the conductor sensor 40 and an instruction is given to set the threshold value Tavg.

[0180] Note that the calculation of the threshold value Tavg may be performed by the conductor sensor 40. That is, the microcomputer 71a may not perform the process of S130, and may instead command the conductor sensor 40 to calculate and set (store) the threshold value Tavg in S140. In this case, the transmission of the pulse width T1 in S60 and the transmission of the pulse width T2 in S120 may be omitted. The transmission of the pulse width T2 in S120 may be omitted.

[0181] In S150, the microcomputer 71a starts timing by the timer. In S160, the microcomputer 71a determines whether or not a completion response has been received from the conductor sensor 40. The first control circuit 48 is configured to transmit a completion response after completing the processes for the commands in S120 and S140.

[0182] If the completion response has not been received, this process proceeds to S170. In S170, it is determined whether or not the timer value is equal to or greater than the first timing threshold value Tth1. If the timer value is less than the first timing threshold value Tth1, this process proceeds to S160. If the timer value is equal to or greater than the first timing threshold value Tth1, this process proceeds to S340. The processes after S340 are the same as the processes after S300.

[0183] If a completion response is received from the conductor sensor 40 in S160, the microcomputer 71a stops the timer in S180 (see FIG. 19) and proceeds to S190. In S190, the microcomputer 71a communicates with the first control circuit 48. Specifically, it commands the first control circuit 48 to write (i.e., set) the completion flag.

[0184] In S200, the microcomputer 71a starts timing by the timer. In S210, the microcomputer 71a determines whether or not a completion response has been received from the conductor sensor 40. The first control circuit 48 is configured to transmit a completion response after completing the writing of the completion flag in response to the command in S190.

[0185] If an end response has not been received, this process proceeds to S220. In S220, it is determined whether the timer value is greater than or equal to the first timing threshold Tth1. If the timer value is less than the first timing threshold Tth1, this process proceeds to S210. If the timer value is greater than or equal to the first timing threshold Tth1, this process proceeds to S230. The processes after S230 are the same as the processes after S300.

[0186] In S210, when an end response is received from the conductor sensor 40, the microcomputer 71a stops the timer in S360. In S370, the microcomputer 71a stops supplying sensor power to the conductor sensor 40, similar to S300. In S380, the microcomputer 71a activates the completion notification unit 73 to perform a completion notification. That is, it notifies the user that the setting of the threshold value Tavg has been completed normally. The completion notification can be performed in any way. For example, it may be notified by displaying a message, or it may be notified by sound.

[0187] (2-1-4-2) Setting of Threshold Value Tavg by the Second Control Circuit Next, the setting of the threshold value Tavg by the main body of the electric working machine 1 will be described with reference to FIG. 20. The setting of the threshold value Tavg can also be performed in a state where the conductor sensor 40 and the detection object 36 are arranged in the state at the time of actual shipment. The setting of the threshold value Tavg in this case is performed by the second control circuit 52 (specifically, the CPU 52a) executing the threshold setting process in FIG. 20. The threshold setting process in FIG. 20 may be performed, for example, by the manufacturer side of the electric working machine 1 before the shipment of the electric working machine 1. Alternatively, it may be performed after shipment as needed (for example, during maintenance, or when the conductor sensor 40 is replaced, etc.).

[0188] When the execution requirement for the threshold setting process is satisfied, the second control circuit 52 executes the threshold setting process according to the program for the threshold setting process stored in the memory 52b. The execution requirement may be determined in any way. For example, the execution requirement may be satisfied when the second control circuit 52 receives an execution command from outside the electric working machine 1 by wired or wireless communication. Also, for example, the execution requirement may be satisfied by a specific operation being performed on the electric working machine 1. This may be the case. The specific operation may be determined in any way. The specific operation may be, for example, a specific first pattern of operation on the mode button 56, a specific second pattern of operation on the trigger switch 6a, or a combination thereof.

[0189] Note that the threshold setting process executed by the second control circuit 52 has many common parts with the threshold setting process executed by the conductor sensor 40 (see FIGS. 17 to 19). Therefore, for the threshold setting process executed by the second control circuit 52, basically, the processes different from those in FIGS. 17 to 19 will be described, and for the processes common to FIGS. 17 to 19, the same reference numerals as in FIGS. 17 to 19 will be given and the description thereof will be omitted. Note that for the processes common to FIGS. 17 to 19, the execution entity may be read as the second control circuit 52.

[0190] After starting the threshold setting process, the second control circuit 52 executes the processes of S20 to S40. Then, when the completion flag is set in the conductor sensor 40 in S40, the process proceeds to S41. In S41, it waits for the user to give a closed position setting notification.

[0191] The closed position setting notification notifies the second control circuit 52 that the cover 30 is in the closed position. When setting the threshold value Tavg on the main body of the electric working machine 1, the user first needs to place the cover 30 in the closed position. With the cover 30 in the closed position, the user performs a predetermined closed position notification operation. The second control circuit 52 can recognize that the closed position notification operation has been performed. In this first embodiment, the second control circuit 52 recognizing that the closed position notification operation has been performed corresponds to the second control circuit 52 being notified (i.e., receiving) the closed position setting notification. The closed position notification operation can be performed in any manner. The closed position notification operation may be, for example, a specific third pattern of operation on the mode button 56, a specific fourth pattern of operation on the trigger switch 6a, or a combination thereof.

[0192] In S42, the second control circuit 52 determines whether it has received the closed position setting notification. If the closed position setting notification has not been received, this process proceeds to S41. If the closed position setting notification has been received, this process proceeds to S60. After going through the processes of S60 to S100, this process proceeds to S101 (see FIG. 21).

[0193] In S101, the second control circuit 52 waits for the user to perform an open position setting notification. The open position setting notification notifies the second control circuit 52 that the cover 30 is in the open position. When setting the threshold value Tavg on the main body of the electric working machine 1, after performing the closed position notification operation, the user needs to move the cover 30 to the open position. With the cover 30 in the open position, the user performs a predetermined open position notification operation. The second control circuit 52 can recognize that the open position notification operation has been performed. In this first embodiment, the second control circuit 52 recognizing that the open position notification operation has been performed corresponds to the second control circuit 52 being notified (i.e., receiving) the open position setting notification. The open position notification operation can be performed in any manner. The open position notification operation may be, for example, a specific fifth pattern of operation on the mode button 56, a specific sixth pattern of operation on the trigger switch 6a, or a combination thereof.

[0194] In S102, the second control circuit 52 determines whether or not an open position set notification has been received. If the open position set notification has not been received, this process proceeds to S101. If the open position set notification has been received, this process proceeds to S120. The processes after S120 are the same as those in FIGS. 18 to 19.

[0195] (2-1-5) Sensor processing by conductor sensor The first control circuit 48 (specifically, CPU 48a) of the conductor sensor 40 is activated when sensor power is supplied. When activated, the first control circuit 48 executes the sensor processing shown in FIG. 22 according to the sensor processing program stored in the memory 52b. The sensor processing is a process for determining whether the cover -30 is in the closed position or the open position.

[0196] When starting the sensor processing, in S410, the first control circuit 48 determines whether or not any command (including an instruction) has been received from the second control circuit 52 or the sensor setting device 71. If a command has been received, this process proceeds to S420.

[0197] In S420, the first control circuit 48 determines the content of the received command. If the received command is the above-described setting command, this process proceeds to S510. In S510, the first control circuit 48 sets the threshold value Tavg by communicating with the transmission source of the setting command (the second control circuit 52 or the sensor setting device 71; hereinafter referred to as the "communication target").

[0198] Specifically, the first control circuit 48 executes completion flag related processing. The completion flag related processing includes notifying the communication target whether or not the completion flag has been set in response to the completion flag confirmation request in S30 described above. S40 described above is performed based on this notification. The completion flag related processing further includes erasing the completion flag when receiving the completion flag erasure command in S250 described above, and transmitting a completion response to the communication target after erasing the completion flag.

[0199] Also, the first control circuit 48 performs various processes based on the commands from the communication target in the aforementioned S60. Specifically, it measures, stores, and transmits to the communication target the pulse width T1. And when these are completed normally, it further transmits a completion notification to the communication target.

[0200] Also, the first control circuit 48 performs various processes based on the commands from the communication target in the aforementioned S120. Specifically, it measures, stores, and transmits to the communication target the pulse width T2. And when these are completed normally, it further transmits a completion notification to the communication target.

[0201] Also, the first control circuit 48 performs various processes based on the commands from the communication target in the aforementioned S140. Specifically, it receives and stores the threshold value Tavg. And when these are completed normally, it further transmits a completion notification to the communication target. As described above, the first control circuit 48 may calculate and store the threshold value Tavg by itself.

[0202] Also, the first control circuit 48 performs various processes based on the commands from the communication target in the aforementioned S190. Specifically, it writes a completion flag. And when the writing of the completion flag is completed normally, it further transmits a completion notification to the communication target.

[0203] In S420, when the received command is a detection command from the electric working machine 1 (i.e., from the second control circuit 52), this process proceeds to S430. The detection command is for instructing to detect the open / closed state of the cover 30, and is transmitted from the second control circuit 52 in S630 of FIG. 23 described later.

[0204] In S430, the first control circuit 48 determines whether a completion flag is written in the first control circuit 48. If the completion flag is not written, that is, if the threshold value Tavg has not been set yet, this process proceeds to S500. In S500, the first control circuit 48 transmits an error response to the second control circuit 52.

[0205] In S430, if a completion flag is written to the first control circuit 48, that is, if the threshold value Tavg is set, this process proceeds to S440. In S440, the first control circuit 48 measures the pulse width Tx of the second pulse signal P4.

[0206] In S450, the first control circuit 48 determines whether the pulse width Tx measured in S440 is greater than the threshold value Tavg. If the pulse width Tx is less than or equal to the threshold value Tavg, this process proceeds to S480. In S480, the first control circuit 48 determines that the cover 430 is in the closed position. In S490, the first control circuit 48 sends a closed response to the second control circuit 52. The closed response indicates that the cover 30 is in the closed position. After S490, this process proceeds to S410.

[0207] In S450, if the pulse width Tx is greater than the threshold value Tavg, this process proceeds to S460. In S460, the first control circuit 48 determines that the cover 430 is in the open position. In S470, the first control circuit 48 sends an open response to the second control circuit 52. The open response indicates that the cover 30 is in the open position. After S470, this process proceeds to S410.

[0208] (2-1-6) Main Process by the Second Control Circuit The main process executed by the second control circuit 52 of the electric working machine 1 will be described with reference to FIG. 23. When starting up, the second control circuit 52 reads and executes the program of the main process in FIG. 23 from the memory 52b. The second control circuit 52 periodically repeats the execution of the main process.

[0209] When the second control circuit 52 starts the main process in FIG. 23, in S610, it determines whether the trigger switch 6a is turned on. If the trigger switch 6a is turned on, this process proceeds to S620.

[0210] In S620, the second control circuit 52 starts supplying sensor power to the conductor sensor 40. In S630, the second control circuit 52 communicates with the first control circuit 48 of the conductor sensor 40. Specifically, it transmits a detection command. Thereby, the conductor sensor 40 determines whether the cover 30 is open or closed. The second control circuit 52 further receives a response transmitted from the conductor sensor 40 in response to the detection command. The possible responses received here are an open response (S470), a closed response (S490), or an error response (S500).

[0211] In S640, the second control circuit 52 determines the content of the received response. If a closed response is received, this process proceeds to S650. In S650, the second control circuit 52 performs a closed-time drive process. The closed-time drive process is the normal drive of the motor 50 corresponding to the case where it is determined that the cover 30 is in the closed position.

[0212] Specifically, in the closed-time drive process, the processes of S660 to S690 are executed. In S660, the second control circuit 52 stops supplying sensor power to the conductor sensor 40. In S670, the second control circuit 52 normally drives the motor 50. Specifically, the rotation of the motor 50 is controlled via the motor drive circuit 51 so that the motor 50 rotates according to the set mode. In S680, the second control circuit 52 determines whether the trigger switch 6a has been turned off. If the trigger switch 6a is on, this process proceeds to S670. If the trigger switch 6a is off, this process proceeds to S690. In S690, the second control circuit 52 stops driving the motor 50.

[0213] In S640, when an open response is received, this process proceeds to S700. In S700, the second control circuit 52 stops supplying sensor power to the conductor sensor 40. In S710, the second control circuit 52 performs notification processing and / or motor restricted driving. The notification processing is a process of notifying the user that the cover 30 is in the open position. The notification processing is performed by operating the display unit 57a and / or the sound generation unit 57b in the notification unit 57. The motor restricted driving includes driving the motor 50 at a rotational speed and / or output torque lower than the normal driving in S670. Alternatively, the motor 50 may be stopped.

[0214] In S720, the second control circuit 52 determines whether the trigger switch 6a has been turned off. If the trigger switch 6a is on, this process proceeds to S710. If the trigger switch 6a is off, this process proceeds to S690.

[0215] In S640, when an error response is received, this process proceeds to S730. In S730, the second control circuit 52 stops supplying sensor power to the conductor sensor 40. In S740, the second control circuit 52 performs error notification. Specifically, it notifies the user that the opening / closing determination of the cover 30 cannot be performed normally. The error processing is performed by operating the display unit 57a and / or the sound generation unit 57b in the notification unit 57.

[0216] (2-1-7) First Modification Example of the Main Process The first modification example of the main process will be described with reference to FIG. 24. Instead of the main process in FIG. 23, the second control circuit 52 may execute the first modification example in FIG. 24. In the main process in FIG. 23, the opening / closing determination of the cover 30 is performed before the motor 50 is driven. In contrast, in the first modification example, in addition to before the motor 50 is driven, the opening / closing determination of the cover 30 is also performed while the motor 50 is being driven.

[0217] The first modification example is partially common to the main process in FIG. 23. Therefore, the same reference numerals as in FIG. 23 are given to the common processes, and hereinafter, the first modification example will be described focusing on the processes different from FIG. 23. What the first modification example differs from the main processing in FIG. 23 is the closing drive processing of S650. In the first modification example, as the closing drive processing, instead of S650, the processing of S800 in FIG. 24 is executed.

[0218] Specifically, the second control circuit 52 first normally drives the motor 50 at S670. Then, at S820, it executes the in-drive processing. Specifically, the second control circuit 52 starts timing by a timer at S830. At S840, the second control circuit 52 performs the same communication as S630. Thereby, the opening and closing determination of the cover 30 is performed by the conductor sensor 40. Also, in the second control circuit 52, an open response, a close response, or an error response is received from the conductor sensor 40.

[0219] At S850, the second control circuit 52 determines the content of the received response. If an open response is received, this processing proceeds to S880. At S880, the second control circuit 52 clears the timer. That is, the timer value is set to the initial value (for example, zero). Note that at S880, it is the timer value that is cleared, and the operation of the timer is not stopped. Therefore, even after the timer value is cleared at S880, the timing by the timer continues from the initial value. After the processing of S890, this processing proceeds to S680.

[0220] If a close response is received at S850, this processing proceeds to S860. At S860, it is determined whether the timer value is equal to or greater than the second timing threshold Tth2. If the timer value is less than the second timing threshold Tth2, this processing proceeds to S680. If the timer value is equal to or greater than the second timing threshold Tth2, this processing proceeds to S890.

[0221] In S890, the second control circuit 52 performs motor limit driving. In S900, the second control circuit 52 issues an error notification. The error notification in S900 notifies the user that the motor 50 has been continuously driven for a period equal to or longer than the second timing threshold value Tth2 with the cover 30 closed. This error notification may be performed in the same manner as in S740 or in a different manner from S740. After the process of S900, this process proceeds to S680.

[0222] If an error response is received in S850, this process proceeds to S910. In S910, the second control circuit 52 stops supplying sensor power to the conductor sensor 40. In S920, the second control circuit 52 issues an error notification, for example, in the same manner as in S740 (FIG. 23). After the process of S920, this process proceeds to S690.

[0223] If the trigger switch 6a is off in S680, the second control circuit 52 stops supplying sensor power in S870 and proceeds to S690. (2-1-8) Second Modification Example of the Main Process The second modification example of the main process will be described with reference to FIG. 25. Instead of the main process of FIG. 23, the second control circuit 52 may execute the second modification example of FIG. 25. In the second modification example, the opening / closing determination of the cover 30 is not performed before the motor 50 is driven, and the opening / closing determination of the cover 30 is performed only while the motor 50 is being driven.

[0224] In the second modification example, in S1010, the second control circuit 52 determines whether the trigger switch 6a has been turned on. If the trigger switch 6a is on, this process proceeds to S1020. In S1020, the second control circuit 52 normally drives the motor 50 in the same manner as in S670. In S1030, the second control circuit 52 starts supplying sensor power to the conductor sensor 40.

[0225] After the process of S1030, this process proceeds to S820. In S820, the same driving-in-process as in S820 of FIG. 24 is performed. (2-1-9) Term Correspondence The saw blade 3 is an example of a cutting tool in the overview of the embodiment. The mounting portion 2a is an example of a tool mounting portion in the overview of the embodiment. The conductor sensor 40 is an example of a conductor detection portion in the overview of the embodiment. The combination of the first control circuit 48 and the second control circuit 52 is an example of a control circuit in the overview of the embodiment. The base portion 10 is an example of a support in the overview of the embodiment. The first cover side plate 31 is an example of a side plate in the overview of the embodiment. The oscillation signal P1, the first pulse signal P3, or the second pulse signal P4 is an example of a detection signal in the overview of the embodiment. The region from the first closed position to the second closed position is an example of a specified region in the overview of the embodiment. The first closed position is an example of a specific position in the overview of the embodiment. The processes of S670 and S710 are examples of predetermined processes in the overview of the embodiment.

[0226] [2-2. Second Embodiment] Referring to FIGS. 26 and 27, the electric working machine 101 of the second embodiment will be described. Note that the position of the cutting plane shown in FIG. 27 corresponds to the cross section XXVII-XXVII of FIG. 3. However, FIG. 27 shows a modified example of the first embodiment and does not show the cross section XXVII-XXVII of FIG. 3 of the first embodiment itself. That is, it should be noted that the cross section XXVII-XXVII of FIG. 3 of the first embodiment is different from FIG. 27.

[0227] The electric working machine 101 includes a cover 300. The cover 300 corresponds to the cover 30 of the first embodiment and is attached to the main body portion 2 in the same manner as the first embodiment. What the electric working machine 101 differs from the electric working machine 1 of the first embodiment is the cover 300. The cover 300 is mostly common with the cover 30 of the first embodiment but is partly different.

[0228] The cover 300 includes a first cover side plate 301 corresponding to the first cover side plate 31 of the first embodiment. In the second embodiment, a detection object 36 is embedded in the first cover side plate 301. Specifically, the detection object 36 is embedded on the side of the first cover outer surface 301a in the first cover side plate 301. However, the surface of the detection object 36 is exposed.

[0229] Such a cover 300 in which the detection object 36 is embedded may be formed in any manner. For example, the detection object 36 and the cover 300 may be integrally formed by insert molding, for example. The same applies to the third and fifth embodiments described later. Alternatively, it may be formed by a method different from integral molding. For example, the detection object 36 may be fitted into a recess in the cover 300 where the detection object 36 is disposed and fixed with an adhesive or the like. The same applies to the fifth embodiment described later.

[0230] In the present second embodiment, as is particularly clear from FIG. 27, the detection object 36 is embedded in the first cover side plate 301 such that the surface of the detection object 36 and the outer surface 301a of the first cover are on the same plane. However, the detection object 36 may be embedded to any extent from the outer surface 301a of the first cover. The detection object 36 may be embedded in the first cover side plate 301 such that a part of the detection object 36 protrudes from the outer surface 301a of the first cover. Conversely, the detection object 36 may be embedded such that the whole of the detection object 36 is located inside the outer surface 301a of the first cover.

[0231] In the present second embodiment, the facing distance between the sensor head 42 and the detection object 36 is slightly larger than the corresponding facing distance in the first embodiment. Therefore, in consideration of the difference in the facing distance, the size (for example, thickness and / or width) of the detection object 36 may be changed (for example, increased) from that in the first embodiment. The same applies to the third to fifth embodiments described later.

[0232] [2-3. Third Embodiment] Referring to FIG. 28, the cover 310 of the third embodiment will be described. The position of the cross-section shown in FIG. 28 corresponds to the cross-section XXVII-XXVII in FIG. 3.

[0233] The cover 310 shown in FIG. 28 corresponds to the cover 30 of the first embodiment and is attached to the main body 2 in the same manner as in the first embodiment. The cover 310 is different from the cover 30 of the first embodiment and the cover 300 of the second embodiment in the structure of the first cover side plate 311. The first cover side plate 311 corresponds to the first cover side plate 31 of the first embodiment. In appearance, the first cover side plate 311 is the same as the first cover side plate 31 of the first embodiment. However, in the third embodiment, the detection object 36 is completely embedded in the first cover side plate 311. The detection object 36 is not exposed outside the cover 310. The surface of the detection object 36 on the side of the first cover outer surface 31a is parallel or substantially parallel to the first cover outer surface 31a.

[0234] [2-4. Fourth Embodiment] Referring to FIGS. 29 and 30, the cover 316 of the fourth embodiment will be described. The position of the cross-sectional plane shown in FIG. 30 corresponds to the cross-section XXVII-XXVII of FIG. 3.

[0235] The cover 316 shown in FIGS. 29 and 30 corresponds to the cover 30 of the first embodiment and is attached to the main body 2 in the same manner as the first embodiment. The cover 316 is different from the cover 30 of the first embodiment in the position where the detection object 36 is attached. In the fourth embodiment, the detection object 36 is fixed on the first cover inner surface 31b of the cover 316.

[0236] [2-5. Fifth Embodiment] Referring to FIG. 31, the cover 310 of the fifth embodiment will be described. The position of the cross-sectional plane shown in FIG. 31 corresponds to the cross-section XXVII-XXVII of FIG. 3.

[0237] The cover 320 shown in FIG. 31 corresponds to the cover 30 of the first embodiment and is attached to the main body 2 in the same manner as the first embodiment. The cover 320 is different from the cover 30 of the first embodiment in the structure of the first cover side plate 321. The first cover side plate 321 corresponds to the first cover side plate 31 of the first embodiment.

[0238] In the fifth embodiment, the detection object 36 is embedded in the first cover side plate 321. Specifically, the detection object 36 is embedded on the side of the first cover inner surface 321b in the first cover side plate 321. However, the surface of the detection object 36 is exposed.

[0239] In the fifth embodiment, the detection object 36 is embedded in the first cover side plate 321 such that the surface of the detection object 36 and the first cover inner surface 321b are on the same plane. However, the detection object 36 may be embedded to any extent from the first cover inner surface 321b. The detection object 36 may be embedded in the first cover side plate 321 such that a part of the detection object 36 protrudes from the first cover inner surface 321b. Conversely, the detection object 36 may be embedded such that the whole of the detection object 36 is present on the inner side of the first cover inner surface 321b.

[0240] [2-6. Sixth Embodiment] Referring to FIG. 32, the cover 30 of the sixth embodiment will be described. The cover 30 of the sixth embodiment is different from the cover 30 of the first embodiment in the position and shape of the detection object 151 and the position of the conductor sensor 40. The detection object 151 corresponds to the detection object 36 of the first embodiment and is provided for the same purpose as that detection object 36.

[0241] In the sixth embodiment, the detection object 151 is fixed on the second cover outer surface 32a of the second cover side plate 32. Focusing only on the position, it can be said that the detection object 151 is obtained by moving the detection object 36 of the first embodiment to the second cover outer surface 32a while maintaining the position in the opening and closing direction.

[0242] The thickness and width of the detection object 151 in the sixth embodiment are the same as those in the first embodiment. However, the thickness and / or width of the detection object 151 may be different from those in the first embodiment. On the other hand, the detection object 151 extends along the rotation direction of the cover 30. That is, the detection object 151 is curved along the rotation direction. The length of the detection object 151 (the length along the rotation direction in this sixth embodiment) is the same as the length of the detection object 36 in the first embodiment. However, the length of the detection object 151 may be different from the length of the detection object 36 in the first embodiment.

[0243] The conductor sensor 40 is fixed to the surface of the second case side plate 22 of the hacksaw blade case 20. More specifically, the conductor sensor 40 is fixed to the rear end and the lower end side of the second case side plate 22.

[0244] The sensor head 42 protrudes from the lower end of the second case side plate 22. The sensor head 42 is separated from the detection object 151 in a direction parallel to the rotation axis 3a (in other words, in the axial direction along the rotation axis 3a). The coil mounting surface of the sensor head 42 is parallel or substantially parallel to the surface of the detection object 151.

[0245] When the cover 30 is in the closed position, the detection object 151 directly faces the sensor head 42 (specifically, the coil mounting surface) in the direction along the rotation axis 3a. When the cover 30 is moved to the open position, the detection object 151 no longer faces the sensor head 42.

[0246] The facing distance between the sensor head 42 and the detection object 151 is the same as that in the first embodiment, but may be different from that in the first embodiment. Note that part or all of the sensor head 42 may not protrude from the lower end of the second case side plate 22 and may directly face the second case side plate 22. In this case, depending on the position of the sensor head 42, the position and / or length of the detection object 151 may be determined as necessary.

[0247] [2-7. Seventh Embodiment] Referring to FIG. 33, the cover 30 of the seventh embodiment will be described. Note that the position of the cross-section shown in FIG. 33 corresponds to the cross-section XXXIII-XXXIII of FIG. 4. However, FIG. 33 shows a modified example of the first embodiment and does not show the cross-section XXXIII-XXXIII of FIG. 4 of the first embodiment itself. That is, it should be noted that the cross-section XXXIII-XXXIII of FIG. 4 of the first embodiment is different from FIG. 33.

[0248] The cover 30 of this seventh embodiment is different from the cover 30 of the first embodiment in the position and shape of the detection object 152 and the position of the conductor sensor 40. The detection object 152 corresponds to the detection object 36 of the first embodiment and is provided for the same purpose as that detection object 36.

[0249] In this seventh embodiment, the detection object 152 is fixed on the outer surface 33a of the third cover side plate 33 of the third cover. Focusing only on the position, it can be said that the detection object 152 is obtained by moving the detection object 36 of the first embodiment to the outer surface 33a of the third cover while maintaining the position in the opening and closing direction.

[0250] The thickness and width of the detection object 152 of this seventh embodiment are the same as those of the first embodiment. However, the thickness and / or width of the detection object 152 may be different from those of the first embodiment. On the other hand, the detection object 152 extends along the rotation direction of the cover 30. That is, the detection object 152 is curved along the rotation direction. The length of the detection object 152 (the length along the rotation direction in this seventh embodiment) is the same as the length of the detection object 36 of the first embodiment. However, the length of the detection object 152 may be different from the length of the detection object 36 of the first embodiment.

[0251] Note that, as an example, the detection object 152 of this seventh embodiment has exactly the same shape and size as the detection object 151 of the sixth embodiment and is fixed to the third cover side plate 33 in the reverse side to the sixth embodiment.

[0252] The conductor sensor 40 is fixed to the surface of the third case side plate 23 of the saw blade case 20. More specifically, the conductor sensor 40 is fixed to the rear end and the lower end side of the third case side plate 23.

[0253] The sensor head 42 protrudes from the lower end of the third case side plate 23. The sensor head 42 is spaced apart from the detection object 152 in a direction parallel to the rotation axis 3a. The coil mounting surface of the sensor head 42 is parallel or substantially parallel to the surface of the detection object 152.

[0254] When the cover 30 is in the closed position, the detection object 152 directly faces the sensor head 42 (specifically, the coil mounting surface) in the direction along the rotation axis 3a. When the cover 30 is moved to the open position, the detection object 152 no longer faces the sensor head 42.

[0255] The facing distance between the sensor head 42 and the detection object 152 may be the same as that in the first embodiment, or may be different from the first embodiment. [2-8. Eighth Embodiment] Referring to FIG. 34, the cover 330 of the eighth embodiment will be described. The cover 330 of the eighth embodiment mainly has two differences compared with the cover 30 of the first embodiment. One of the differences is the material of the cover 330, and the other difference is that it is provided with a notch 335.

[0256] The cover 330 of the eighth embodiment contains metal. The cover 330 may be mixed with metal and a non-conductor (for example resin). The cover 330 may contain any metal. In the eighth embodiment, the cover 330 contains non-ferrous metal. Non-ferrous metal means a metal other than iron. The entire cover 330 may be made of non-ferrous metal.

[0257] The cover 330 does not contain iron. However, the cover 330 may contain iron within a range where the determination of the open / closed state of the cover 330 can be properly performed. The cover 330 may contain any non-ferrous metal. The cover 330 may contain, for example, aluminum, copper, magnesium, and / or titanium, etc. In the eighth embodiment, as an example, the cover 330 contains magnesium. The entire cover 330 may be composed of magnesium.

[0258] The shape of the cover 330 is basically the same as that of the first embodiment 30. However, as shown in FIG. 34, the shape of the first cover side plate 331 is partially different from that of the first cover side plate 31 of the first embodiment. Specifically, the first cover side plate 331 of the eighth embodiment is provided with a notch 335. The first cover side plate 331 has a predetermined region cut out from the end on the opening side toward the closing direction. The cut-out portion, that is, the space where there is no tangible object, corresponds to the notch 335.

[0259] The length of the above-mentioned predetermined region along the circumferential direction (i.e., the length of the notch 335) is the same as or approximately equal to the length of the detection object 36 in the first embodiment. That is, the first cover side plate 331 of the eighth embodiment can be regarded as, in appearance, the first cover side plate 31 of the first embodiment with the detection object 36 removed and the region where the detection object 36 was attached cut out.

[0260] In the eighth embodiment, the notch 335 corresponds to the detection object of the present disclosure. When the cover 330 is in the closed position (between the first closed position and the second closed position), the notch 335 faces the sensor head 42. When the cover 330 is opened and moves away from the closed position, the notch 335 no longer faces the sensor head 42. That is, in the open position of the cover 330, the region of the first cover outer surface 331a of the first cover side plate 331 other than the notch 335 (hereinafter referred to as the "non-notch region") faces the sensor head 42.

[0261] When the sensor head 42 faces the notch 335 and when it does not, the oscillation frequency of the oscillation circuit 45 is different. Specifically, the oscillation frequency when the sensor head 42 faces the notch 335 is lower than the oscillation frequency when the sensor head 42 faces the non-notch region. Therefore, the pulse width of the second pulse signal PA when the sensor head 42 faces the notch 335 is larger than the pulse width when the sensor head 42 faces the non-notch region.

[0262] Also in the eighth embodiment, for example, the threshold value setting process of FIGS. 20 to 21 may be executed with the conductor sensor 40 mounted on the electric device 1, and the threshold value Tavg may be calculated and stored. In this case, the first pulse width T1 may be measured in a state where the sensor head 42 faces the notch 335 (for example, the fully closed position), and the second pulse width T2 may be measured in a state where the sensor head 42 does not face the notch 335 (for example, the fully open position). Then, based on the measured first and second pulse widths T1 and T2, the threshold value Tavg may be calculated in the same manner as in the first embodiment, for example.

[0263] And, in S450 of the conductor sensor 40 according to the eighth embodiment, contrary to the first embodiment, when the detected pulse width Tx is larger than the threshold value Tavg, it may shift to S480 and determine that the cover 330 is in the closed position. On the other hand, when the detected pulse width Tx is less than or equal to the threshold value Tavg, the conductor sensor 40 may shift to S460 and determine that the cover 330 is in the open position.

[0264] Since the notch 335 is a non-conductor (specifically, a space) and the non-notch region is a conductor, alternatively, the non-notch region may be regarded as the detection object. In such a view, the conductor sensor 40 may determine that the cover 330 is in the open position when detecting the detection object and determine that the cover 330 is in the closed position when the detection object is not detected.

[0265] Also, in the cover 330, the metal may be contained anywhere and in any manner. For example, the metal may be uniformly contained throughout the cover 330. Also, for example, in the cover 330, the inclusion rate of the metal may vary depending on the location, the type of the metal may vary depending on the location, or there may be a portion that does not contain the metal. The inclusion rate of the metal is, for example, the amount of the metal per unit volume. For example, while the first cover side plate 331 contains the metal, the second cover side plate 32 and / or the third cover side plate 33 may not contain the metal. The metal may be contained anywhere and in any manner in the cover 330 as long as the determination of the open / closed state of the cover 330 can be appropriately performed.

[0266] [2-9. Ninth Embodiment] Referring to FIG. 35, the cover 340 of the ninth embodiment will be described. The cover 340 of the ninth embodiment has a form in which the detection object 160 is disposed (or in other words, fitted) in the notch 335 of the cover 330 of the eighth embodiment. The material of the cover 340 other than the detection object 160 contains a non-ferrous metal (for example, magnesium) and does not contain iron.

[0267] On the other hand, the material (or main component) of the detection object 160 may be any material whose electrical characteristics with respect to the alternating magnetic field are different from those of the cover 330. That is, the detection object 160 may have a material such that the oscillation frequency of the oscillation circuit 45 is different when the sensor head 42 faces the detection object 160 and when it faces the outer surface 331a of the first cover other than the detection object 160.

[0268] For example, in the ninth embodiment, since the main component of the cover 340 is magnesium, the detection object 160 may contain a metal or a non-metal (for example, resin) different from magnesium. Even when the main component of the cover 340 is a non-ferrous metal other than magnesium, the detection object 160 may contain, as the main component, a substance different from the non-ferrous metal.

[0269] The detection object 160 may have a material different from non-ferrous metals as its main component. Specifically, the detection object 160 may contain iron or an alloy containing iron as its main component. The detection object 160 may be composed of a non-metal (for example, a material containing resin) without containing a metal.

[0270] Even in such a ninth embodiment, for example, in the same manner as in the eighth embodiment, the threshold value Tavg may be calculated, and the opening / closing determination of the cover 340 may be performed based on the threshold value Tavg. [2-10. Tenth Embodiment] Referring to FIG. 36, the cover 350 of the tenth embodiment will be described. The cover 350 of the tenth embodiment is partially different in the shape of the first cover side plate 351 from the first cover side plate 31 of the first embodiment.

[0271] The first cover side plate 351 of the present tenth embodiment includes a detection object 352, a first notch 353, and a second notch 354 at the end on the opening direction side thereof. That is, if only the shape is considered, the first cover side plate 351 of the present tenth embodiment can be said to be obtained by notching the end on the opening direction side of the first cover side plate 31 of the first embodiment as shown in FIG. 36.

[0272] The first and second notches 353 and 354 are provided on both sides in the left-right direction of the detection object 352 at the end on the opening direction side of the first cover side plate 351. The lengths of the first and second notches 353 and 354 are, for example, the same as the length of the notch 335 in FIG. 34.

[0273] The detection object 352 extends in the opening direction from the end of the first cover side plate 351. The length of the detection object 352 is, for example, the same as the length of the detection object 36 in the first embodiment. That is, when the cover 350 is in the closed position, the detection object 352 faces the sensor head 42, and when the cover 350 moves to the open position, the detection object 352 no longer faces the sensor head 42.

[0274] Cover 350 has the same material as cover 330 of the eighth embodiment. That is, cover 350 as a whole contains metal. Specifically, cover 350 contains non-ferrous metal. Cover 350 may be made of, for example, magnesium or a magnesium alloy. Similar to cover 330 of the eighth embodiment, cover 350 may not contain iron. However, cover 350 may contain iron within the range where the determination of the open / closed state of cover 350 can be properly performed. Cover 350 may be a mixture of metal and a non-conductor (e.g., resin).

[0275] The material of the detection object 352 is the same as that of cover 350. Detection object 352 may be integrally formed with cover 350. That is, cover 350 may be an integrally molded product including detection object 352.

[0276] The material of the detection object 352 is the same as that of the first cover side plate 351 (i.e., the same conductor as each other). However, the shapes of the portions of the detection object 352 and the first cover side plate 351 facing the sensor head 42 are different from each other. Specifically, the width of the detection object 352 is smaller than the width of the first cover side plate 351. In other words, the area of the region of the sensor head 42 where the detection object 352 faces when the cover 350 is in the fully closed position (an example of the first area in the summary of the embodiment) is smaller than the area of the region of the sensor head 42 where the first cover outer surface 351a of the first cover side plate 351 faces when the cover 350 is in the open position (an example of the second area in the summary of the embodiment). Specifically, in the tenth embodiment, the width of the detection object 352 is 1 / 2 or less of the width of the first cover outer surface 351a. Note that the width of the detection object 352 may be greater than 1 / 2 of the width of the first cover outer surface 351a.

[0277] In the tenth embodiment, as in the eighth embodiment, the oscillation frequency of the oscillation circuit 45 is different between when the sensor head 42 faces the object 352 to be detected and when it does not face the object 352 to be detected (that is, when it faces the outer surface 351a of the first cover). Specifically, the oscillation frequency when the sensor head 42 faces the object 352 to be detected is lower than the oscillation frequency when the sensor head 42 does not face the object 352 to be detected. Therefore, also in the tenth embodiment, for example, in the same manner as in the eighth embodiment, the threshold value Tavg may be calculated, and the opening / closing determination of the cover 350 may be performed based on the threshold value Tavg.

[0278] In the cover 350, the metal may be contained anywhere and in any manner. For example, the metal may be uniformly contained in the entire cover 350. Also, for example, in the cover 350, the inclusion rate of the metal may vary depending on the location, the type of the metal may vary depending on the location, or there may be a portion that does not contain the metal. For example, the second cover side plate 32 and / or the third cover side plate 33 may not contain the metal. Also, for example, either one of the first cover side plate 351 and the object 352 to be detected may not contain the metal. The metal may be contained anywhere and in any manner in the cover 350 as long as the opening / closing state of the cover 350 can be appropriately determined.

[0279] [2-11. Eleventh Embodiment] With reference to FIG. 37, the cover 360 of the eleventh embodiment will be described. Eleventh Embodiment The cover 360 of the eleventh embodiment is partially different in the shape of the first cover side plate 361 from the first cover side plate 31 of the first embodiment.

[0280] The first cover side plate 361 of the eleventh embodiment includes the object 362 to be detected at the end portion on the opening direction side. That is, if only the shape is concerned, it can be said that the first cover side plate 361 of the eleventh embodiment is obtained by expanding the area of the end portion on the opening direction side of the first cover side plate 31 of the first embodiment in the width direction as shown in FIG. 37.

[0281] The object to be detected 362 extends in the opening direction from the end of the first cover side plate 361. The length of the object to be detected 362 is the same as that of the object to be detected 36 in the first embodiment, for example. That is, when the cover 360 is in the closed position, the object to be detected 362 faces the sensor head 42, and when the cover 360 moves to the open position, the object to be detected 362 no longer faces the sensor head 42.

[0282] The material of the cover 360 is the same as that of the tenth embodiment. The material of the object to be detected 362 is the same as that of the cover 360. The object to be detected 362 may be integrally formed with the cover 360. That is, the cover 360 may be an integrally molded product including the object to be detected 362. The cover 360 may not contain iron, similar to the cover 350 of the tenth embodiment. However, the cover 360 may contain iron within a range where the determination of the open / closed state of the cover 360 can be properly performed. The cover 360 may be a mixture of a metal and a non-conductor (e.g., resin).

[0283] The material of the object to be detected 362 is the same as that of the first cover side plate 361 (i.e., the same conductor as each other). However, the shapes of the portions of the object to be detected 362 and the first cover side plate 361 facing the sensor head 42 are different from each other. Specifically, the width of the object to be detected 362 is larger than the width of the first cover side plate 361. In other words, the area of the region where the object to be detected 362 faces in the sensor head 42 when the cover 360 is in the fully closed position (an example of the first area in the summary of the embodiment) is larger than the area of the region where the first cover outer surface 361a of the first cover side plate 361 faces in the sensor head 42 when the cover 360 is in the open position (an example of the second area in the summary of the embodiment). Specifically, in the eleventh embodiment, the width of the object to be detected 362 is at least twice the width of the first cover outer surface 361a. Note that the width of the object to be detected 362 may be smaller than twice the width of the first cover outer surface 361a.

[0284] In the 11th embodiment, as in the 1st embodiment, the oscillation frequency of the oscillation circuit 45 is different when the sensor head 42 faces the object to be detected 362 and when it does not face the object to be detected (i.e., when it faces the outer surface 361a of the first cover). Specifically, the oscillation frequency when the sensor head 42 faces the object to be detected 362 is higher than the oscillation frequency when the sensor head 42 does not face the object to be detected 362. Therefore, also in this 11th embodiment, for example, in the same manner as in the 1st embodiment, the threshold value Tavg may be calculated, and the opening / closing determination of the cover 360 may be performed based on the threshold value Tavg.

[0285] Note that the statement “in the cover 350, the metal may be included anywhere in any manner” described in the 10th embodiment and its specific examples are similarly applicable to the cover 360 of this 11th embodiment. In the case of this 11th embodiment, for example, either one of the first cover side plate 361 and the object to be detected 362 may not contain metal. The metal may be included anywhere in any manner in the cover 360 as long as the opening / closing state of the cover 360 can be properly determined.

[0286] [2-12. 12th Embodiment] Referring to FIG. 38, the cover 380 of the 12th embodiment will be described. Note that the position of the cross-section shown in FIG. 38 corresponds to the cross-section XXXVIII-XXXVIII of FIG. 7. However, FIG. 38 shows a modified example of the 1st embodiment and does not show the cross-section XXXVIII-XXXVIII of FIG. 7 of the 1st embodiment itself. That is, it should be noted that the cross-section XXXVIII-XXXVIII of FIG. 7 of the 1st embodiment is different from FIG. 38.

[0287] The cover 380 of this 12th embodiment is partially different in the shape of the first cover side plate 381 from the cover 30 of the first embodiment. The first cover side plate 381 includes a thick plate portion 382 and a thin plate portion 383. The thick plate portion 382 corresponds to a certain region from the end on the opening direction side to the closing direction in the first cover side plate 381. The thin plate portion 383 corresponds to the portion other than the thick plate portion 382 in the first cover side plate 381. That is, the thin plate portion 383 corresponds to a certain region from the end on the closing direction side to the opening direction (up to the end on the closing direction side of the thick plate portion 382) in the first cover side plate 381.

[0288] The thickness of the thick plate portion 382 is larger than the thickness of the thin plate portion 383. Specifically, the thickness of the thick plate portion 382 is 2 times or more the thickness of the thin plate portion 383. However, the thickness of the thick plate portion 382 may be smaller than 2 times the thickness of the thin plate portion 383. The thickness of the thick plate portion 382 is an example of the first thickness in the general description of the embodiment, and the thickness of the thin plate portion 383 is an example of the second thickness in the general description of the embodiment.

[0289] In this 12th embodiment, the thick plate portion 382 functions as a detection object, and the thin plate portion 383 functions as a surrounding member. The length of the thick plate portion 382 is, for example, the same as the length of the detection object 36 of the first embodiment. That is, when the cover 380 is in the closed position, the thick plate portion 382 faces the sensor head 42, and when the cover 380 moves to the open position, the thick plate portion 382 no longer faces the sensor head 42.

[0290] The material of the cover 380 is the same as that of the cover 350 of the 10th embodiment and includes metal (for example, non-ferrous metal) as a whole. The cover 380 may be an integrally formed product including the thick plate portion 382 and the thin plate portion 383. Similar to the cover 350 of the 10th embodiment, the cover 380 may not contain iron. However, the cover 380 may contain iron within the range where the determination of the open / closed state of the cover 380 can be properly performed. The cover 380 may be a mixture of metal and a non-conductor (for example, resin).

[0291] The material of the thick plate portion 382 is the same as that of the thin plate portion 383 (i.e., the same conductor as each other). However, the shapes of the portions of the thick plate portion 382 and the thin plate portion 383 facing the sensor head 42 are different from each other. Specifically, the thickness of the thick plate portion 382 is larger than the thickness of the thin plate portion 383. Therefore, the oscillation frequency of the oscillation circuit 45 is different when the sensor head 42 faces the thick plate portion 382 and when it does not face (i.e., faces the thin plate portion 383). Specifically, the oscillation frequency when the sensor head 42 faces the thick plate portion 382 is higher than the oscillation frequency when the sensor head 42 faces the thin plate portion 383. Therefore, also in the present 12th embodiment, for example, in the same manner as in the 1st embodiment, the threshold value Tavg may be calculated, and the opening / closing determination of the cover 380 may be performed based on the threshold value Tavg.

[0292] Note that the matter of "in the cover 350, the metal may be contained anywhere and in any manner" described in the 10th embodiment, and its specific examples are similarly applicable to the cover 380 of the present 12th embodiment. In the case of the present 12th embodiment, for example, either one of the thick plate portion 382 and the thin plate portion 383 may not contain metal. The metal may be contained anywhere and in any manner in the cover 380 as long as the opening / closing state of the cover 380 can be appropriately determined.

[0293] [2-13. 13th Embodiment] Referring to FIG. 39, the cover 390 of the 13th embodiment will be described. Note that the position of the cross-section shown by FIG. 39 corresponds to the cross-section XXXVIII-XXXVIII of FIG. 7, similar to FIG. 38.

[0294] The cover 390 of this 13th embodiment is partially different in the shape of the first cover side plate 391 from the cover 30 of the first embodiment. The first cover side plate 391 includes a thin plate portion 392 and a thick plate portion 393. The thin plate portion 392 corresponds to a certain region from the end on the opening side to the closing direction in the first cover side plate 391. The thick plate portion 393 corresponds to the portion other than the thin plate portion 392 in the first cover side plate 391. That is, the thick plate portion 393 corresponds to a certain region from the end on the closing side to the opening direction (up to the end on the closing side of the thin plate portion 392) in the first cover side plate 391.

[0295] The thickness of the thin plate portion 392 is smaller than the thickness of the thick plate portion 393. Specifically, the thickness of the thin plate portion 392 is 1 / 2 or less of the thickness of the thick plate portion 393. However, the thickness of the thin plate portion 392 may be greater than 1 / 2 of the thickness of the thick plate portion 393. The thickness of the thin plate portion 392 is an example of the first thickness in the summary of the embodiment, and the thickness of the thick plate portion 393 is an example of the second thickness in the summary of the embodiment.

[0296] In this 13th embodiment, the thin plate portion 392 functions as a detection object. The length of the thin plate portion 392 is, for example, the same as the length of the detection object 36 of the first embodiment. That is, when the cover 390 is in the closed position, the thin plate portion 392 faces the sensor head 42, and when the cover 390 moves to the open position, the thin plate portion 392 no longer faces the sensor head 42.

[0297] The material of the cover 390, that is, the materials of the thin plate portion 392 and the thick plate portion 393, are the same as those of the cover 350 of the 10th embodiment and include metal (for example, non-ferrous metal) as a whole. The cover 390 may be an integrally formed product including the thin plate portion 392 and the thick plate portion 393. Similar to the cover 350 of the 10th embodiment, the cover 390 may not contain iron. However, the cover 390 may contain iron within the range where the determination of the open / closed state of the cover 390 can be properly performed. The cover 390 may be a mixture of metal and a non-conductor (for example, resin).

[0298] The material of the thin plate portion 392 is the same as that of the thick plate portion 393 (i.e., the same conductor as each other). However, the shapes of the portions of the thin plate portion 392 and the thick plate portion 393 facing the sensor head 42 are different from each other. Specifically, the thickness of the thin plate portion 392 is greater than the thickness of the thick plate portion 393. Therefore, the oscillation frequency when the sensor head 42 faces the thin plate portion 392 is lower than the oscillation frequency when the sensor head 42 faces the thick plate portion 393. Therefore, in the present 13th embodiment, for example, in the same manner as in the 8th embodiment, the threshold value Tavg may be calculated, and the opening / closing determination of the cover 380 may be performed based on the threshold value Tavg.

[0299] Note that the matter of "in the cover 350, metal may be included anywhere in any manner" described in the 10th embodiment, and its specific examples are similarly applicable to the cover 390 of the present 13th embodiment. In the case of the present 13th embodiment, for example, either one of the thin plate portion 392 and the thick plate portion 393 may not contain metal. Metal may be included anywhere in any manner in the cover 390 as long as the opening / closing state of the cover 390 can be properly determined.

[0300] [2-14. 14th Embodiment] Referring to FIG. 40, the cover 400 of the 14th embodiment will be described. In the present 14th embodiment, a long plate-shaped or long foil-shaped conductor 410 extends over the entire closing direction side of the position of the detection object 36 in the 1st embodiment on the outer surface 31a of the 1st cover. The width and thickness of the conductor 410 are, for example, the same as those of the detection object 36 in the 1st embodiment. In the present 14th embodiment, In the region where the detection object 36 was arranged in the 1st embodiment, no conductor is arranged. In the present 14th embodiment, the material of the cover 400 other than the conductor 410 is a non-conductor (for example, resin), the same as the cover 30 in the 1st embodiment.

[0301] In the 14th embodiment, the region on the outer surface 31a of the first cover, which is on the opening side with respect to the conductor 410 (hereinafter referred to as the "detection target region"), functions as a detection target. The length of the detection target region is, for example, the same as the length of the detection target 36 in the first embodiment. That is, when the cover 400 is in the closed position, the detection target region faces the sensor head 42. When the cover 400 moves to the open position, the detection target region no longer faces the sensor head 42, and the conductor 410 comes to face the sensor head 42.

[0302] With such a configuration, the oscillation frequency when the sensor head 42 faces the detection target region is lower than the oscillation frequency when the sensor head 42 faces the conductor 410. Therefore, in the 14th embodiment, for example, in the same manner as in the 8th embodiment, the threshold value Tavg may be calculated, and the opening / closing determination of the cover 380 may be performed based on the threshold value Tavg.

[0303] Alternatively, the conductor 410 may be regarded as a detection target. In such a case, when the conductor sensor 40 detects the detection target, it may be determined that the cover 400 is in the open position, and when the detection target is not detected, it may be determined that the cover 400 is in the closed position.

[0304] [2-15. Other Embodiments] As described above, the embodiments of the present disclosure have been described. However, the present disclosure is not limited to the above-described embodiments and can be implemented with various modifications.

[0305] (2-15-1) Part or all of the sensor circuits 43 on the sensor substrate 41 may be provided outside the sensor substrate 41 (that is, outside the conductor sensor 40). For example, the first control circuit 48 may be omitted from the sensor substrate 41. In this case, the first control circuit 48 may be provided in, for example, the second control circuit 52. Alternatively, the CPU 52a of the second control circuit 52 may also have the function of the first control circuit 48 (that is, the opening / closing determination).

[0306] When the first control circuit 48 is omitted from the sensor substrate 41 as described above, the conversion circuit 46 may also be omitted from the sensor substrate 41. In this case, the conversion circuit 46 may be provided in the second control circuit 52. In addition to the conversion circuit 46, the frequency division circuit 47 may also be omitted from the sensor substrate 41. In this case, the frequency division circuit 47 may also be provided in the second control circuit 52.

[0307] (2-15-2) The frequency division circuit 47 may be omitted. That is, the first control circuit 48 may perform the opening / closing determination of the cover 30 based on the first pulse signal P3 from the conversion circuit 46. (2-15-3) The conductor sensor 40 may perform the opening / closing determination of the cover 30 based on a physical quantity or a signal different from the second pulse signal P4. The conductor sensor 40 may, for example, detect the frequency of the oscillation signal P1 and perform the opening / closing determination based on the frequency.

[0308] Alternatively, the conductor sensor 40 may perform the opening / closing determination based on the amplitude of the oscillation signal P1. For example, when the amplitude is equal to or less than a predetermined amplitude threshold value, it may be determined as the closed position, and when the amplitude is greater than the amplitude threshold value, it may be determined as the open position.

[0309] (2-15-4) The oscillation circuit 45 may be in the form of a separately excited oscillation circuit. When the oscillation circuit 45 is separately excited, the amplitude of the oscillation signal P1 or the power supplied to the conductor sensor 40 (for example, current) may change according to the distance to the detection object. Therefore, the position of the cover 30 may be detected based on these physical quantities that can change.

[0310] (2-15-5) In the sensor head 42 shown in FIG. 11, the coil L1 has a rectangular shape as a whole. However, the coil L1 may have a shape different from a rectangle. The coil L1 may have, for example, a circular shape or a polygonal shape other than a quadrilateral.

[0311] (2-15-6) In the three types of main processes (Figs. 23 to 25) of the first embodiment, while the trigger switch 6a is on, the conductor sensor 40 is driven to determine whether the cover 30 is open or closed. However, the opening / closing determination may be made while the trigger switch 6a is off. For example, in any one or all of Figs. 23 to 25, even while the trigger switch 6a is off, sensor power may be supplied to the conductor sensor 40 at a predetermined timing, and the opening / closing determination may be made. And when the cover 30 is in the open position, for example, the same process as the notification process of S710 (Fig. 23) may be performed.

[0312] (2-15-7) The combination of the materials of the cover and the detection object of the present disclosure is not limited to the combinations of the above embodiments, and may be a combination such that the oscillation frequency changes when the cover is in the closed position and when it is in the open position.

[0313] For example, in the first embodiment, among the cover 30 and the detection object 36, one may contain a conductor (e.g., aluminum, copper, magnesium, iron, graphite, etc.), and the other may contain a non-metal (e.g., resin, ceramic, glass, rubber, etc.). Also, for example, one of the cover 30 and the detection object 36 may be a non-ferrous metal that does not contain iron, and the other may be a metal different from the one and does not contain iron, a metal containing iron, or a non-metal.

[0314] (2-15-8) In the first embodiment, the detection object 36 may be arranged anywhere and in any manner on the cover 30. When the detection object 36 is embedded in the cover 30, the detection object 36 may be embedded in the cover 30 in any manner and / or to any extent. The detection object 36 may be embedded in the cover 30 in a manner different from the second, third, and fifth embodiments. For example, the detection object 36 may be embedded in the cover 30 such that only a specific part of the detection object 36 is exposed. The detection object 36 may be embedded in the cover 30 such that a part of the detection object 36 is exposed on the outer surface 31a side of the first cover and another part is exposed on the inner surface 31b side of the first cover.

[0315] (2-15-9) The area from the first closed position to the second closed position, and the closed area angle corresponding to that area, may be determined in any way. In the above first embodiment, when the cover 30 was between the first closed position and the second closed position, it was determined as the "closed position". However, the areas or positions determined as the "closed position" and the "open position" may be determined in any way. For example, when the cover 30 is in the fully closed position, it may be determined as the "closed position", and when it moves in the opening direction from the fully closed position, it may be determined as the "open position". The same applies to each of the other embodiments.

[0316] (2-15-10) The present disclosure is applicable to covers in various forms. The cover may be movable in any way. For example, the cover may be linearly movable. Also, the cover may be movable in any direction. For example, the cover may be movable in a direction along the rotation axis, or may be movable in the radial direction of the rotation radius. Also, the cover may be fixedly attached to the main body and not movable. Also, the cover of the present disclosure may be configured to cover any part of the cutting tool in any way. Also, the cover of the present disclosure may be arranged anywhere in the electric working machine in any way.

[0317] Also, the conductor sensor of the present disclosure may have a sensing method different from the eddy current type. The conductor sensor of the present disclosure may be a sensor (for example, a capacitance type) that can sense a conductor without contact. It may be.

[0318] (2-15-11) The electric working machine to which the present disclosure is applicable is not limited to the form of the maruko in the above embodiment. The present disclosure can be applied to, for example, any electric tool or electric working machine used on-site. Specifically, for example, the present disclosure can be applied to a grinder, a handy saw, a power cutter, a reciprocating saw, a chainsaw, a jigsaw, a lawn mower, etc. The cutting tool of the present disclosure is also not limited to the nokoblade 3.

[0319] (2-15-12) The present disclosure is not limited to applications to battery-driven power working machines. The present disclosure is also applicable to power working machines configured to operate by receiving power supply from sources other than batteries (for example, commercial AC power supplies).

[0320] (2-15-13) A plurality of functions of one component in the above embodiment may be realized by a plurality of components, or one function of one component may be realized by a plurality of components. Further, a plurality of functions of a plurality of components may be realized by one component, or one function realized by a plurality of components may be realized by one component. Further, a part of the configuration of the above embodiment may be omitted. Further, at least a part of the configuration of the above embodiment may be added to or replaced with the configuration of another above embodiment.

Description of Reference Numerals

[0321] 1,101…Power working machine, 2…Main body portion, 2a…Mounting portion, 3…Noko blade, 3a…Rotating shaft, 10…Base portion, 30,300, 310,316,320,330,340,350,360,380,390,400,430…Cover, 31…First cover side plate, 31a…Outer surface of the first cover, 31b…Inner surface of the first cover, 36,151,152,160,352,362…Detection object, 40…Conductor sensor, 42…Sensor head, 48…First control circuit, 52…Second control circuit.

Claims

1. A motor, A tool mounting portion configured such that a cutting tool that can cut a workpiece by being rotated is mounted thereon, or the cutting tool is detachably mounted, and configured to transmit the rotation of the motor to the cutting tool to rotate the cutting tool; A conductor detection unit having a sensor head configured to non - contactingly sense a conductive member, and configured to output a detection signal that changes according to the distance between the sensor head and the member, the material of the member, and / or the shape of the member; A combined member disposed at a distance from the sensor head, A cover configured to cover a covered area of a part of the outer peripheral edge along the rotation direction of the cutting tool, and A detection object attached to the cover or included in the cover and arranged such that the distance from the sensor head changes according to the position of the cover, Including, the cover and / or the detection object being a conductor, arranged such that the detection signal is different according to whether the cover is within a specified region, and when the cover is within the specified region, the cover covers a predetermined range or more of the covered area, A combined member configured as such, An electric working machine comprising the same.

2. The electric working machine according to Claim 1, wherein the conductor detection unit is adjacent to the cover in a non - contacting manner. An electric working machine.

3. The electric working machine according to Claim 1 or Claim 2, comprising a control circuit configured to execute a predetermined process based on the position of the cover indicated by the detection signal. An electric working machine.

4. The electric working machine according to any one of Claims 1 to 3, wherein the cover is configured to be movable within a predetermined movable range including the specified region. An electric working machine.

5. The electric working machine according to Claim 4, wherein the specified region extends from a first specified position to a second specified position within the movable range, and the first specified position corresponds to the position of the cover when the cover covers the covered area and the cover is at an end of the movable range. An electric working machine.

6. The electric working machine according to Claim 5, comprising a main body portion that houses the motor and to which the combined member is attached, and a support configured to rotatably support the main body portion within a range of a predetermined rotation angle. Comprising. The cover is configured to be in the first specified position when no external force due to contact is applied from outside the electric working machine, (ii) to contact the support body in response to rotation of the main body portion, receive the external force from the support body, and be moved from the first specified position toward the second specified position by the external force, and (iii) reach the second specified position when the main body portion is rotated by the predetermined rotation angle. Electric working machine.

7. The electric working machine according to any one of Claims 1 to 6, The detection target is disposed on the cover so as to face the sensor head when the cover is at at least a specific position within the specified region. Electric working machine.

8. The electric working machine according to any one of Claims 1 to 7, The cover is configured to rotate along the circumferential direction of the cutting tool about the rotation axis of the cutting tool, The conductor detection unit is disposed away from the cover in the radial direction of the rotation radius of the cover and so as to face the sensor head in the radial direction of the rotation radius. Electric working machine.

9. The electric working machine according to any one of Claims 1 to 7, The cover is configured to rotate along the circumferential direction of the cutting tool about the rotation axis of the cutting tool, The conductor detection unit is disposed away from the cover in the axial direction along the rotation axis and so as to face the sensor head in the axial direction. Electric working machine.

10. The electric working machine according to any one of Claims 1 to 9, The cover includes a side plate facing the cutting tool, The detection target is embedded inside the side plate and does not protrude outside the side plate. Electric working machine.

11. The electric working machine according to any one of Claims 1 to 9, The cover includes a side plate facing the cutting tool, The detection target is provided on the outer surface of the side plate that does not face the cutting tool so that the detection target protrudes from the side plate toward the outer surface side. Electric working machine.

12. The electric working machine according to any one of Claims 1 to 9, The cover includes a side plate facing the cutting tool, The object to be detected is provided on the inner surface of the side plate facing the cutting tool so that the object to be detected protrudes from the side plate toward the inner surface side. Electric working machine.

13. An electric working machine according to any one of Claims 1 to 12, wherein the object to be detected is a conductor, and the cover has a material different from that of the object to be detected and is non-metallic. Electric working machine.

14. An electric working machine according to any one of Claims 1 to 12, wherein the object to be detected is a metal containing iron or a non-metal, and the cover is a non-ferrous metal. Electric working machine.

15. An electric working machine according to any one of Claims 1 to 12, wherein the object to be detected is integrally included in the cover, the cover and the object to be detected are metals, the cover is configured such that when the cover is at at least a specific position within the specified region, the object to be detected faces the sensor head, and when the cover deviates from the specified region, a peripheral member of the cover different from the object to be detected faces the sensor head, the object to be detected has a first thickness, the peripheral member has a second thickness, the first thickness and the second thickness are lengths along the direction in which the object to be detected and the peripheral member face the sensor head, and the first thickness is different from the second thickness. Electric working machine.

16. An electric working machine according to Claim 15, wherein the first thickness is two times or more the second thickness, or 1 / 2 or less the second thickness. Electric working machine.

17. An electric working machine according to any one of Claims 1 to 12, wherein the object to be detected is integrally included in the cover, the cover and the object to be detected are metals, the cover is configured such that when the cover is at at least a specific position within the specified region, the object to be detected faces the sensor head, and when the cover deviates from the specified region, a peripheral member of the cover different from the object to be detected faces the sensor head. The first area, which is the area of the portion of the detection object facing the sensor head when the surrounding member faces the detection object, is different from the second area, which is the area of the portion of the surrounding member facing the sensor head when the surrounding member faces the sensor head. Electric working machine.

18. The electric working machine according to claim 17, wherein the first area is at least twice the second area or at most 1 / 2 of the second area. Electric working machine.

19. The electrical device according to any one of claims 1 to 18, wherein only one of the cover and the detection object is a conductor. Electrical device.

20. The electrical device according to any one of claims 1 to 18, wherein the cover and the detection object are different conductors from each other. Electrical device.

21. The electrical device according to any one of claims 1 to 18, wherein the cover and the detection object are the same conductor as each other and have different shapes from each other. Electrical device.

22. The electric working machine according to any one of claims 1 to 21, wherein the electric working machine is a circular saw, and the cutting tool includes a saw blade having a disc shape and provided with a plurality of teeth along the outer periphery. Electric working machine.

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