JP5974526B2 - Electric working machine - Google Patents

Description

  The present invention relates to an electric working machine driven by a motor.

  2. Description of the Related Art As a working machine for cutting grass and vegetation, a brush cutter in which a rotary blade is driven is known. Up until now, brush cutters have generally used an internal combustion engine as a power source. However, as the performance of rechargeable secondary batteries has improved, electric brush cutters have been put into practical use and are widely used. If the power source of the brush cutter is electric power, there is a feature that the exhaust gas is not generated silently and the running cost is excellent. Such an electric brush cutter is disclosed in Patent Document 1, and is configured such that the rotational speed of the motor can be adjusted. The configuration of such a conventional electric brush cutter will be described with reference to FIG. The electric brush cutter 1001 driven by the battery pack 1002 has a motor unit 1004 attached to the tip of a pipe-shaped ridge 1006, and the battery pack 1002 drives a motor (not shown) housed in the motor unit 1004 to drive the cutting blade 1005. Rotate. In the vicinity of the cutting blade 1005, a scattering protection cover 1011 for preventing scattering of the grass that has been cut off is provided. The electric brush cutter 1001 is carried by a shoulder belt (not shown) or the like, and a handle pipe 1007 having a substantially U-shape in front view for operation by an operator is attached to the vicinity of the longitudinal center portion of the rod 1006. Grip portions 1008 a and 1008 b are provided at both ends of the pipe 1007. In the vicinity of the handle 1007 between the handle 1007 and the operation unit 1003 of the heel 1006, there is provided a waist support member 1012 that is applied to the operator's waist during work. The rotation of the motor unit 1004 is controlled by an operator by a trigger lever 1009 attached to the grip unit 1008a. The rotation speed of the motor unit 1004 can be changed by changing the voltage applied to the motor, and is adjusted by the dial 1010. Thus, it is possible to change the rotation speed of the blade according to the object to be cut and its shape.

JP 2011-142859 A

  In the electric brush cutter described in Patent Document 1, since the length of the hook 1006 is unchanged and cannot be adjusted, it is possible to realize an electric brush cutter that has a sense of rigidity and is easy to use despite being lightweight. . However, there have been many requests from users to realize a compact electric brush cutter that can reduce the storage space. For this reason, the applicant has commercialized an electric brush cutter that reduces the storage size by allowing the hook shape to be divided into joint types. However, in order to further facilitate the storage work from the time of storage to the time of use or after use. Further studies have been repeated.

  The present invention has been made in view of the above background, and an object of the present invention is to realize an electric working machine that can make a heel a contraction type and have a compact shape when stored.

  Another object of the present invention is to provide a detecting means for detecting the expansion / contraction state of the heel so that when the heel is contracted for some reason during the operation with the heel extended, the motor is immediately braked. It is to realize an electric work machine with improved safety.

  Still another object of the present invention is that after detecting that the kite is contracted and the brake is applied, the stretched state of the kite is returned to the original stretched state, and then the trigger switch is released once. An object of the present invention is to realize an electric working machine with improved safety by not allowing the motor to be restarted until it is gripped again.

  The characteristics of representative ones of the inventions disclosed in the present application will be described as follows.

According to one aspect of the present invention, a motor, a fixed portion provided with a handle having a grip portion, a movable portion that is slidably held by being extended with respect to the fixed portion, and for rotating the motor An electric working machine having a trigger switch and a control unit for controlling the rotation of the motor, and the movable unit having a cutting blade driven by a motor at the tip of a movable pipe connected to the fixed unit. provided detection means for detecting whether or not positioned in a predetermined extended position and connected to the control unit with respect to parts, during the rotation of the motor in the trigger switch is turned on, when the trigger switch oN state is released Apply braking force to the motor. In addition, when the detection unit detects that the movable part is retracted from the extended position while the motor is rotating while the trigger switch is on, the control unit applies a braking force to the motor even when the trigger switch is on. I made it. Further, the controller continues to brake the motor until the trigger switch is released from the ON state and the detection result of the detection means is switched from the non-extension position to the extension position.

  According to still another feature of the present invention, an informing means for indicating a driving state of the motor is provided, and an alarm is issued by the informing means while the control unit continues to brake the motor. The notification means is, for example, a display lamp, and the alarm is indicated by lighting or blinking of the display lamp. The controller restarts the rotation of the motor when the trigger switch is pulled again after the trigger switch is released and the detection result of the detection means is switched from the non-extension position to the extension position.

  According to the first aspect of the present invention, the braking force is applied to the motor when the detecting means detects that the motor has been switched from the extended position to the non-extended position while the motor is rotating. The rotation of the motor can be stopped safely.

According to the second aspect of the present invention, since the action of the braking force is electrically controlled by the control unit, the strength and timing at which the brake is applied can be controlled by the control unit.

According to the invention of claim 3, since the control unit continues the braking of the motor until the trigger switch is released and the detection result by the detecting means is switched from the non-extension position to the extension position, the motor is surely secured until safety can be confirmed. Can be maintained in a stopped state. Further, the rotation of the motor does not start unless the operator releases the trigger switch once to return to a safe state and pulls the trigger switch again. Therefore, an abnormal operation contrary to the operator's intention does not occur, and a highly safe heel telescopic electric working machine can be realized.

  According to the fourth aspect of the present invention, the notifying means for indicating the driving state of the motor is provided, and the alarm is issued by the notifying means while the control unit continues to brake the motor. Can easily know that has stopped.

  According to the invention of claim 5, since the notification means is a display lamp and the alarm is lighting or blinking of the display lamp, the notification means can be easily realized by using an inexpensive LED or the like. The rise can be suppressed. In addition, by changing the display mode such as blinking and displaying, it is possible to use the existing display lamp or the like as a notification means.

  According to the sixth aspect of the present invention, the controller is configured to release the trigger switch when the trigger switch is pulled again after the trigger switch is released and the detection result by the detecting means is switched from the non-extension position to the extension position. Since the rotation is resumed, the motor can be started after confirming the intention of the operator to resume the work in addition to the confirmation of the safety, and the electric working machine can be improved in safety.

  The above and other objects and novel features of the present invention will become apparent from the following description and drawings.

It is a side view which shows the whole electric brush cutter which concerns on the Example of this invention, and shows the state at the time of expansion | extension of a cocoon. It is a side view which shows the whole electric brush cutter which concerns on the Example of this invention, and shows the state at the time of the accommodation of a cocoon (at the time of non-extension). It is an enlarged view of the operation part 10 of the electric brush cutter 1 of FIG. It is sectional drawing of the connection part 50 of the electric brush cutter 1 of FIG. 1 (the 1). It is sectional drawing of the connection part 50 of the electric brush cutter 1 of FIG. 1 (the 2). It is sectional drawing of the AA part of FIG. It is a circuit diagram of the electric brush cutter 1 of FIG. It is a control flowchart of the electric brush cutter 1 of FIG. It is a flowchart which shows the detailed procedure of the eyelid expansion / contraction detection routine of step 263,268 of FIG. It is a figure which shows the example of a determination table used by the wrinkle expansion / contraction detection routine of FIG. It is a circuit diagram of the electric brush cutter which concerns on 2nd Example of this invention. It is a control flowchart of the 2nd example of the present invention. It is a flowchart which shows the detailed procedure of the soft brake control in step 424 of FIG. It is a figure which shows the PWM control example at the time of the electric brake control of the electric brush cutter of the 2nd Example of this invention. It is a figure which shows the example of a combination of the display pattern of the display lamp used by control of FIG. It is a figure which shows the example of the drive part which concerns on the other Example of an electrically-driven working machine. It is a perspective view which shows the whole shape of the conventional electric brush cutter.

  Embodiments of the present invention will be described below with reference to the drawings. In the following drawings, the same portions are denoted by the same reference numerals, and repeated description is omitted. Further, in this specification, description will be made assuming that the front, rear, left, right, and up and down directions are directions shown in the drawing.

As shown in FIG. 1, an electric brush cutter 1 that is one of the electric working machines includes an operation unit 10 to which the battery pack 2 is attached, a telescopic ridge fixed to the vicinity of the front end of the operation unit 10, It is configured to include a drive unit 151 attached to the tip and a handle unit 41 fixed near the center in the front-rear direction of the bag. In this embodiment, the telescopic hook is composed of a fixed pipe 40 and a movable pipe 80 that is connected to the front side of the fixed pipe 40 and can move relative to the fixed pipe 40 in the front-rear direction. 40, the handle part 41, and the connecting part 50 constitute the fixed part 3 for fixing the movable pipe , and the movable part 80 and the drive part 151 constituting the main part of the work equipment attached to the front side thereof are fixed parts 3. It becomes the movable part 4 which becomes a part which moves with respect to.

A battery pack 2 that houses a plurality of secondary batteries such as lithium ion batteries is mounted on the housing 11 of the operation unit 10, and a control unit (for driving a motor included in the drive unit 151) is installed inside the housing 11. Controller) and a booster circuit that boosts the DC voltage supplied from the battery pack 2 to a predetermined DC voltage and supplies the boosted DC voltage to the motor. A fixed pipe 40 is attached to the front side from the operation unit 10. The fixed pipe 40 is a metallic cylindrical member such as an aluminum alloy, for example, and a handle portion 41 is disposed near the center of the fixed pipe 40 in the front-rear direction. The handle portion 41 includes a hollow handle pipe 42 that is substantially U-shaped when viewed from the front, and includes grip portions 43 that are attached to both ends of the handle pipe 42. The right portion of the two grip portions 43 is formed as an operation portion, and a trigger lever 44 that can swing around a rotation axis is connected to the grip portion 43. A wire 26 is connected to the trigger lever 44, and the trigger lever 44 is coupled to the switch 21 disposed in the operation unit 10 via the wire 26. A lock lever 45 is provided on the front side of the trigger lever 44. The handle pipe 42 is bolted to the fixed pipe 40 using a handle holder 46. The fixing position of the handle holder 46 with respect to the fixing pipe 40 may be adjustable in the front-rear direction within a predetermined range. Behind the handle holder 46, a belt holding portion 47 is provided for attaching a shoulder suspension belt.

A small-diameter movable pipe 80 is connected to the front side of the large-diameter fixed pipe 40 fixed to the housing 11. Similarly to the fixed pipe 40, the movable pipe 80 is preferably composed of a cylindrical member made of metal such as an aluminum alloy, and the movable pipe 80 is disposed so as to enter the inside of the fixed pipe 40. A connection method is adopted so that the fixed position of the movable pipe 80 and the fixed pipe 40 can be adjusted, and the length of the ridge formed of the movable pipe 80 and the fixed pipe 40 can be made variable. The connection between the fixed pipe 40 and the movable pipe 80 is fixed by a holder 51, and the holder 51 is provided with a fixing lever 62 for restricting the movement of the movable pipe 80 in the front-rear direction (axial direction). The movable pipe 80 is moved in the front-rear direction with the fixed lever 62 operated to loosen the fixed state of the movable pipe 80 by the holder 51, and the fixed lever 62 is operated at a predetermined position (extension position) to move the movable pipe. By tightening 80 with the holder 51, the movable pipe 80 is fixed so as not to move in the front-rear direction. The electric brush cutter 1 performs the work in a state where the movable pipe 80 is extended most with respect to the fixed pipe 40 as shown in FIG. In addition, the holder 51 is provided with an expansion / contraction detection means to be described later, and is configured so that the drive unit 151 does not operate when the movable pipe 80 is not fully extended (non-extended state). Further, when the fixed state of the movable pipe 80 is incomplete, or when the movable pipe 80 contracts for some reason during the mowing operation, the rotation operation of the drive unit 151 is automatically stopped. .

  The handle portion 41 is attached to the fixed pipe 40. By attaching to the fixed pipe 40, the rigidity of the waist pad portion 28 and the operation portion 10 from the handle portion 41 can be increased. In addition, since the shoulder suspension belt is also held by the belt holding portion 47 attached to the fixed pipe 40, all the parts to which force is applied during the work are attached to the fixed pipe 40. The shape of the handle pipe 42 may be the same as the shape of the handle pipe 1007 described in FIG. 17, but not only the handle pipe 42 having a substantially U shape in front view but also a loop handle widely used in brush cutters. (D-shaped handle) may be used. Even when a D-shaped handle is used, it is important that the handle pipe is fixed not on the movable pipe 80 side but on the fixed pipe 40 side. The wire 26 connected to the trigger lever 44 of the handle portion 41 is connected to the operation portion 10 through the inside of the waist rest portion 28 along the fixed pipe 40 from the handle pipe 42. Further, a bellows tube 27 covering a connection line (described later) for transmitting an output from an expansion / contraction detecting means described later extends from the holder 51 of the connection unit 50, and extends along the fixed pipe 40 to the waist pad 28. And is connected to the operation unit 10. A cord stopper 12 is provided in front of the housing 11 of the operation unit 10 to hold the wire 26 and the bellows tube 27 so as not to move in the front-rear direction.

  The drive unit 151 houses a motor (described later) with a DC brush such as a so-called coreless motor inside a motor case 152 manufactured by molding an aluminum alloy or the like, and rotates the cutting blade 155 by the rotation of the motor. Since an electric motor is used in this way, extremely high noise reduction can be ensured as compared with a brush cutter using a two-cycle engine. A fan cover 154 is provided below the motor accommodated in the motor case 152, and a cutting blade 155 is attached to an output shaft (not shown) protruding downward from the fan cover 154 using a holder 156. A scattering protection cover 170 that covers a part of the cutting blade 155 is provided adjacent to the motor attached to the tip of the movable pipe 80. The cutting blade 155 can be a metal circular tip saw, but is not limited to this, and any other cutting means such as a nylon cord cutter, a reciprocating clipper means, a trimmer means or the like may be used. good.

  Inside the motor case 152 is housed a coreless motor (not shown) that rotates at a speed corresponding to the input voltage. The coreless motor is relatively lightweight because there are no gears or cores, and the cutting blade is directly driven by the central axis of the coreless motor, that is, the cutting blade is directly connected to the coreless motor without using a gear or the like. Therefore, mechanical loss can be suppressed, and further, no gear noise is generated and noise generation is small. Furthermore, since the coreless motor is configured to rotate by generating a magnetic flux that passes through the coil substrate in the axial direction of the central axis, a configuration in which the rotational axis of the motor is inclined at about 45 degrees at the tip of the movable pipe 80. However, the rotating shaft of the motor does not protrude in the direction of the central axis in the vertical direction of the drive unit 151, and a compact shape can be achieved.

  FIG. 2 shows the electric brush cutter 1 in a state where the movable pipe 80 is most contracted with respect to the fixed pipe 40. In this embodiment, for example, in the extended state of FIG. 1, the total length (distance from the rear end of the battery pack 2 to the front end of the motor case 152 of the drive unit 151) is 1880 mm. With such an arrangement, the operation unit 10 and the drive unit 151 are arranged sufficiently apart from each other, and the center of gravity of the electric brush cutter 1 is sufficiently separated from the operation unit 10. Improves. On the other hand, when the electric brush cutter 1 is stored and transported, it is in a contracted state as shown in FIG. The splash protection cover 170 also serves as a stopper for the movement position during expansion and contraction by contacting the holder 51 when the movable pipe 80 is contracted. The total length at this time is about 1350 mm, and the wrinkles can be shortened by 500 mm or more. In the contracted state of FIG. 2, it is important to configure so that the motor cannot be driven even if the trigger lever 44 is pulled.

  FIG. 3 is an enlarged view of the operation unit 10 of the electric brush cutter 1 of FIG. 1 and shows a state where one of the left and right split type housings 11 is removed. The fixed pipe 40 is shown in a sectional view, not a side view. The operation unit 10 accommodates a circuit board 13 on which a booster circuit and a control circuit (controller) are mounted. A fixed pipe 40 is attached to the attachment boss 34 on the front side of the housing 11. The fixed pipe 40 is a hollow tube formed of a light and strong material such as an aluminum alloy or reinforced plastic, and has a substantially circular cross section, and a curl cord 35 is disposed therein. The curl cord 35 serves as a power supply line for supplying motor driving power from the circuit board 13 to the motor (see FIG. 1). The housing 11 is divided into left and right parts and can be divided into two parts, and a fixed pipe 40 is held by a mounting boss 34 part which is manufactured by molding integrally with the inner wall part. An abutting surface 34a is formed on the rear surface of the mounting boss 34, and a fixing tool 33 for fixing the vicinity of the end of the curl cord 35 is provided in the vicinity of the abutting surface 34a. A cord stopper 12 for fixing the wire 26 and the bellows tube is provided on the front side of the housing 11 and in the vicinity of the base of the fixing pipe 40. The signal line 58 is for transmitting a signal from an expansion / contraction detecting means described later, and is protected by the bellows tube 27 from disconnection due to bending.

  The battery attachment portion 11a is a portion for attaching the battery pack 2 as a power source, and serves as a connection portion with the power source. As shown in FIG. 1, the battery pack 2 can be attached to the battery attachment portion 11 a while sliding the battery pack 2 downward. The battery mounting portion 11 a is provided with a terminal base 14 that holds a plurality of terminals 15. When the battery pack 2 is mounted on the battery mounting portion 11 a, the output terminal (not shown) of the battery pack 2 is the terminal 15. Can be connected to the circuit board 13. The terminal 15 and the circuit board 13 are connected by a plurality of lead wires 17. An operation panel 16 on which a main power switch (described later), a battery remaining amount display section, and a main LED (Light Emitting Diode) are arranged is provided on the upper surface of the housing 11. When the main power switch is turned on, power is supplied to a microcomputer (described later) mounted on the circuit board 13, and a standby mode for power supply to the motor is set. When the main power switch is off, no electric power is output from the circuit board 13 to the motor even if the trigger lever 44 (see FIG. 1) is pulled. The electric power from the circuit board 13 is supplied to the motor via the telescopic curl cord 35. The curl cord 35 is also called a spring cable, and is formed by covering a plurality of electric wires wound in a coil shape that expands and contracts with a resin and is used in a place where expansion and contraction is required, and has excellent wear resistance. It has a feature that it can withstand repeated use. The curl cord 35 has straight end portions 35b formed at both ends of a spring portion 35a wound in a coil shape. In this embodiment, the curl cord 35 is formed inside the fixed pipe 40 and the movable pipe 80. It arrange | positions in space and arrange | positions so that the curl code | cord 35 may not be seen from an operator. The other end of the curl cord 35 not shown in FIG. 3 is disposed at a mounting portion (not shown) between the drive unit 151 and the movable pipe 80 and is inserted into the drive unit 151 via a connection terminal (not shown). Connected to the positive and negative terminals of the motor to be accommodated.

  The rotational speed of the motor that drives the cutting blade 155 is set by a dial 20 provided on the operation panel 16, and a DC voltage supplied to the motor from a booster circuit (not shown) is set so as to be the set rotational speed. When the trigger lever 44 (see FIG. 1) is pulled in the standby mode in which the main power switch is on, a predetermined voltage of direct current is supplied from the circuit board 13 to the motor. When the trigger lever 44 is pulled, the wire 26 is pulled, and the wire end 26a moves, whereby the movable plate 23 moves in the front-rear direction. The rear end portion of the movable plate 23 is disposed so as to contact the plunger 22 of the switch 21, the movement of the wire 26 is transmitted to the switch 21, and when the trigger lever 44 is pulled, the switch 21 is turned on (connected state). In the present embodiment, the trigger switch is configured by the trigger lever 44, the wire 26, the movable plate 23, the switch 21, and the like. However, the trigger switch 44 is not configured by a plurality of parts in this way (see FIG. 1). ) May be arranged so as to be integrated with the lever, and the lead wire may be transmitted into the housing 11 instead of the wire 26, or may be realized by other switch means. Anyway. The setting of the dial 20 is transmitted to the circuit board 13 as a change in resistance value, and a microcomputer (hereinafter referred to as “microcomputer”) described later outputs a voltage that is output according to the on / off state of the trigger lever 44 and the setting value of the dial 20. Adjust.

  The circuit board 13 includes a booster circuit (not shown) that boosts the voltage output from the battery pack 2 to a high voltage for a DC motor. For this reason, on the circuit board 13, electronic elements for a booster circuit such as a plurality of capacitors 31, 32 and a coil 29 are mounted. The degree to which the voltage is boosted with respect to the magnitude of the output voltage of the battery pack 2 is determined according to the set value of the rotary dial 20. In this embodiment, for example, a 14.4V or 18V lithium ion battery is used as the battery pack 2, and a brushed DC motor with a rating of 38V is used as the motor. Thus, regardless of the output voltage of the battery pack 2, the circuit board 13 supplies the motor with a value voltage according to the set value of the dial 20, so the type (rated voltage) of the battery pack 2 is not limited. In addition, by using the booster circuit, it is possible to work at a sufficiently high rotational speed even with a battery having a small capacity. The combination of the type and rated voltage of the battery pack 2 and the motor to be used, and how much the voltage is boosted by the booster circuit is arbitrary, and other configurations other than the example shown in the present embodiment may be used. .

  Connection from the power supply line 18 extending from the circuit board 13 to the curl cord 35 which is another power supply line is performed via the connection terminal 30. In this embodiment, the curl cord 35 is configured to have two wires, plus and minus. The circuit board 13 has a function of protecting the battery pack 2 and the motor from overcurrent and overvoltage, and when the overcurrent and overvoltage are detected, the power supplied to the motor is forcibly cut off or the motor is supplied with a brake current. A controller (described later) is provided that performs control to brake the rotation of the motor. The specific circuit configuration and operation of the controller mounted on the circuit board 13 will be described later. The cord stopper 12 provided on the front side of the housing 11 guides the signal line 58 by holding the bellows tube 27 and the wire 26 and prevents malfunction due to bending of the wire 26 or the like. An LED 381 is provided on the top of the cord stopper 12.

  Next, the detailed structure of the connection part 50 of the electric brush cutter 1 is demonstrated using FIG.4 and FIG.5. 4 and 5 are cross-sectional views of the connection portion 50 of the electric brush cutter 1. FIG. 4 shows a state in which the movable pipe 80 is locked so as not to move in the axial direction with respect to the fixed pipe 40 in the extended state in which the movable pipe 80 is most extended. In such a state where the cocoon is extended, that is, in the extended state of the movable pipe 80, the mowing work can be performed. A holding tool 51 is fixed to a distal end portion of the fixed pipe 40 and a connection portion with the movable pipe 80. The holder 51 is provided with an extension detecting means for accommodating a lock mechanism for fixing the movable pipe 80 to the fixed pipe 40 and for detecting whether or not the movable pipe 80 extends to a predetermined extension position. It is a member for. The holder 51 is divided into left and right parts, and each is manufactured by integral molding of a polymer resin such as plastic. The left and right divided parts are screwed together so as to sandwich the fixed pipe 40 with seven screws (not shown) provided on the screw bosses 59a to 59g. In addition, in order to fix the holding tool 51 and the fixing pipe 40 more firmly, you may make it fix together with an adhesive agent. The rear end portion of the stopper 52 is disposed so as to come into contact with the front end surface of the fixed pipe 40 and holds the movable pipe 80 on the inner peripheral side of the cylindrical stopper 52 so as to be movable in the axial direction (front-rear direction). A through hole 80b is formed in a part of the movable pipe 80, and a part of the ball 60 moves from the radially outer side to the inner side and enters the through hole 80b in the expansion / contraction position so that there is a click feeling when extended. It was constructed so that the fixed position of can be seen. On the outer peripheral side (lower side in the figure) of the ball 60, the ball 60 is urged against the movable pipe 80 side by a spring 61 held inside the holder 51. The spring 61 is accommodated in a cylindrical spring accommodating portion 51 d formed in a part of the casing of the stopper 52.

  To release the lock mechanism of the movable pipe 80 by the ball 60, when the movable pipe 80 is moved strongly toward the fixed pipe 40, the lock state is released because the ball 60 moves against the urging force of the spring 61. . However, in the lock mechanism only with the ball 60, the locked state may be released during the mowing work. Therefore, in this embodiment, in addition to the lock mechanism using the ball 60, the movable pipe 51a operates in cooperation with the spring plates 51a provided on the left and right sides of the holder 51, thereby reducing the distance between the two spring plates 51a. A locking mechanism that strongly tightens 80 is used together. A fixed lever 62 (see FIG. 1) is provided to sandwich the movable pipe 80 between the two spring plates 51a and strongly limit the movement of the movable pipe 80 in the axial direction.

  Inside the switch box 51b of the holder 51, there are provided two systems of extension detection means for detecting whether or not the movable pipe 80 is extended to a predetermined position. The extension detection means detects the position and state of the movable pipe 80 by an arbitrary detection method such as electrical, mechanical, and optical, and outputs it to a control means (controller) mounted on the circuit board 13 by an electrical signal. . One of the extension detecting means is a mechanical switch 55 such as a micro switch, and a pulley 55b is provided at the tip of a lever 55a that is turned on or off. In this embodiment, when the pulley 55b moves downward in the figure, the lever 55a pushes the plunger of the switch 55 to turn on the switch 55. When the pulley 55b is at the upper position as shown, the lever 55a is turned to the plunger of the switch 55. Is opened, the switch 55 is turned off. The switch 55 is connected to the circuit board 13 (see FIG. 3) via a signal line 58. A sleeve 53 is provided in the vicinity of the pulley 55 b and at the rear end of the movable pipe 80.

Since the curl cord 35 (not shown), the pulley 55b, and the lever 55a are separated by the sleeve 53, the curl cord 35 does not come into contact with the lever 55a during operation. In addition, since it is not necessary to provide a recess for switching on / off of the switch 55 in the movable pipe 80 itself, the movable pipe 80 is not distorted or bent. The sleeve 53 is formed with a hook-shaped latching portion 53c, and when the sleeve 53 is fitted into the movable pipe 80, the latching portion 53c is fitted into a rectangular hollow hole 80a formed in the movable pipe 80. Thus, the sleeve 53 is fixed so as not to come out of the movable pipe 80. Further, since the sleeve 53 is provided so as to cover at least a part of the outer peripheral side of the movable pipe 80, the front end portion of the sleeve 53 comes into contact with the rear end portion of the stopper 52 when the movable pipe 80 is pulled out to the maximum extent. It functions to prevent the movable pipe 80 from coming off from the fixed pipe 40. Furthermore, the sleeve 53 has recesses 53a are provided on the sliding portion between the pulley 55b of the switch 55, the switch 55 is off state by moving the lever 55a by the pulley 55b is positioned in the recess 53a. An inclined surface 53b is formed at a transition portion from the concave portion 53a of the sleeve 53 to the outer diameter portion on the front side thereof. When the movable pipe 80 is contracted to the fixed pipe 40 side from the state of FIG. the switch 55 by guiding and 55b radially outwardly from the off state (situation of FIG. 4), can be shifted to the on-state to be described later with reference to FIG 5.

  Another extension detection means for detecting whether or not the sensor is extended is a magnet 54 and a Hall IC 56 provided in a part of the sleeve 53. The Hall IC 56 is an element in which a magnetic field is detected using the Hall effect. In this embodiment, the output is in a Low state when the magnet 54 is close to the Hall IC 56, and the magnet 54 is moved from the Hall IC 56. The output is configured to be in a high state in a separated state. The output of the Hall IC 56 is transmitted to the circuit board 13 through the signal line 58 together with the signal of the switch 55. The signal line 58 is a four-wire cable, and is arranged inside the bellows tube 27 so as not to be disconnected due to externally applied force or vibration. Further, the extraction of the bellows tube 27 from the holder 51 is fixed by the signal line guide 51c. Although not shown in FIGS. 4 and 5, the curl cord 35 shown in FIG. 3 is arranged from the fixed pipe 40 to the movable pipe 80, and the curl cord 35 is arranged in a variable distance portion to the motor. Is done. On the other hand, since the signal line 58 is a cable for connecting a distance invariable portion between the holder 51 and the operation unit 10, there is no need to use a telescopic cable such as a curl cord. Therefore, in this embodiment, the signal line 58 is arranged not to be inside the fixed pipe 40 but to be turned outside. The reason why the signal line 58 is arranged outside the fixed pipe 40 and the curl cord 35 is arranged inside the fixed pipe 40 in this way is to prevent the expansion and contraction of the curl cord 35 as much as possible. This is for ease of wiring and aesthetics. Of course, the signal line 58 may be arranged inside the fixed pipe 40, but in that case, it is preferable to consider that the expansion and contraction of the curl cord 35 is not hindered by the signal line 58. The wiring inside the fixed pipe 40 and the movable pipe 80 may be any expansion / contraction means or wiring that is not affected by expansion / contraction on the pipe side. Also good. Further, since the bellows tube 27 is for protecting the signal line 58, it may be combined with any tube-like member.

  FIG. 5 is a diagram showing a state slightly contracted from the extended state of FIG. In order to contract in this way, it is necessary to move the movable pipe 80 after releasing the tightening state by the fixed lever 62 (see FIG. 1). In this contracted state, the pulley 55b passes over the inclined surface 53b and is positioned at (is riding on) the thick diameter portion of the sleeve 53. For this reason, since the lever 55a is pressed against the switch 55 side, the switch 55 is turned on. Further, since the magnet 54 is located away from the Hall IC 56, the magnetic field of the magnet 54 does not act on the Hall IC 56, so the output of the Hall IC 56 is in a High state indicating that the magnet 54 is away. On the other hand, since the through hole 80b of the movable pipe 80 is located away from the ball 60, the ball 60 moves downward (outward in the radial direction when viewed from the movable pipe 80) against the urging force of the spring 61.

  6 is a cross-sectional view taken along a line AA in FIG. 4 and 5 is tightened by a bolt 63 in the portion (near 64) of the spring plate 51a without the inner surface of the left portion 51-1 and the right portion 51-2 being in contact with each other. It becomes the composition which is done. The bolt 63 is configured so that the movable pipe 80 is tightened by moving the fixed lever 62 to the illustrated position, and the left portion 51-1 and the right side are swung by swinging the fixed lever 62 in the direction of the arrow 65 from the illustrated state. The space | interval of the part 51-2 comes to leave | separate. The center 66 of the fixed lever 62 swinging in the direction of the arrow 65 and in the opposite direction is near the head of the bolt 63. By swinging the fixed lever 62 in the direction of the arrow 65, the clamped state of the movable pipe 80 via the stopper 52 is released, and when the fixed lever 62 is moved closer to the holder 51 as shown in FIG. The movable pipe 80 is strongly tightened via the screw. In addition, what is necessary is just to use a well-known fastening technique for the structure which tightens with the fixing lever 62. FIG. In this embodiment, the cross-sectional shape of the movable pipe 80 is not a perfect circle, and a rail portion 80c (a groove portion when viewed from the outside in the radial direction) continuous in the axial direction is formed in the lower portion. Although not shown, rail portions corresponding to the rail portions 80c are also formed on the fixed pipe 40 side, and the movable pipe 80 and the fixed pipe 40 are held so as not to rotate relative to each other by engaging the rail portions with each other. . Thus, although the manufacturing cost becomes high by forming the rail part 80c, the rigidity of the movable pipe 80 and the fixed pipe 40 can be improved, and it can be set as a rigid but highly rigid eaves structure.

  Next, a circuit diagram of the electric brush cutter 1 will be described with reference to FIG. The controller 201 described in this circuit diagram is mounted on the circuit board 13. In addition, although an actual circuit is provided with a flyback type booster circuit, the description and explanation are omitted in this embodiment for convenience of explanation. The controller 201 inputs power from the battery pack 2 and rotates the motor 153 connected to the output side. The motor 153 is a brushless coreless motor driven by direct current, and the number of rotations thereof varies depending on the magnitude of the direct current voltage applied to the motor 153. The controller 201 mainly includes a switch (trigger switch) 21, a main power switch circuit 214, a battery voltage detection circuit 235, a trigger detection circuit 240, a main power automatic stop circuit 203, a constant voltage circuit 207, a microcomputer. 211 and an output stop circuit 243.

  When the battery pack 2 is attached to the battery attachment portion 11a (see FIG. 3), power is supplied from the battery pack 2 to the controller 201 via the terminal 15 (+ terminal 15a, −terminal 15b). Next, when the main power switch 220 of the main power switch circuit 214 is turned on, a voltage from the battery pack 2 is applied to the constant voltage circuit 207, so that a low voltage direct current of 5 V, for example, is supplied to the microcomputer 211. Starts. From the circuit diagram, the terminal 15 seems to have only terminals 15a and 15b connected to the positive terminal (+) and the negative terminal (−) of the battery pack 2, but in reality, the terminal 15 is the LD terminal of the battery pack 2. Other terminals such as a terminal connected to the terminal and a terminal connected to the ID terminal of the battery pack 2 are also provided. Further, although a circuit for connecting the LD terminal and the ID terminal and the microcomputer 211 is also provided, in the circuit diagram of FIG. The constant voltage circuit 207 is a known DC-DC converter including a three-terminal regulator 209 including three terminals, an input terminal, an output terminal, and a ground, and oscillation prevention capacitors 208 and 210 provided before and after the three-terminal regulator 209. It is. The output voltage of the constant voltage circuit 207 is supplied to the microcomputer 211 and each electronic element in the controller.

  The main power switch circuit 214 includes a main power switch 220 configured by a soft touch switch or the like provided on the operation panel 16 (see FIG. 3), and a circuit for maintaining a state in which the main power switch 220 is turned on. It is comprised. A circuit for maintaining the state where the main power switch 220 is turned on includes transistors 221, 226, 228, FET 230, capacitor 219, resistors 215, 217, 218, 222-227, 231 and diodes. 216. The main power switch circuit 214 repeats the main power-on state and the main power-off state each time the touch-type main power switch 220 is pressed. In this embodiment, the main power switch circuit 214 is maintained in the ON state by the configuration of the electric circuit. However, this is configured so that the FET 230 can be shut off by the microcomputer 211, and according to the instruction on the microcomputer 211 side. This is for turning off the main power supply (a circuit for this will be described later).

  The output of the main power switch circuit 214 is input to the battery voltage detection circuit 235 and the constant voltage circuit 207. The battery voltage detection circuit 235 includes a series circuit of a voltage dividing resistor 236 and a voltage dividing resistor 237, and one end of the voltage dividing resistor 236 is connected to the A / D input terminal of the microcomputer 211. On the other hand, outputs from the plus terminal and minus terminal of the battery pack 2 are connected to the motor 153 via the switch 21, the output stop circuit 243, and the diode 257. In an electric power tool, the motor is usually configured to rotate when the switch 21 is turned on. However, in this embodiment, the motor 153 must be pulled if the switch 21 is not pulled while the main power switch circuit 214 is turned on. It was configured not to rotate. The output stop circuit 243 is a circuit for forcibly stopping the rotation of the motor 153 under the control of the microcomputer 211 even when the switch 21 is on. The trigger detection circuit 240 includes a series circuit of a voltage dividing resistor 241 and a voltage dividing resistor 242, and one end of the voltage dividing resistor 241 is connected to the A / D input terminal of the microcomputer 211.

  The output stop circuit 243 is provided with an output stop FET 245. For example, a MOS type can be used for the FET 245, and the source and drain can be switched between a conductive state and a non-conductive state by turning on or off the gate signal. The gate signal of the FET 245 is grounded through the resistor 247 and the FET 248. The gate signal of the FET 248 is connected to the D / A output terminal of the microcomputer via the resistor 249. When the High signal is output from the microcomputer, the FET 248 is turned on to apply a predetermined voltage to the gate signal of the FET 245, and the FET 245 is turned on, so that the motor 153 starts rotating by pulling the switch 21. On the other hand, when the Low signal is output from the microcomputer 211, the FET 248 is turned off, so that the gate signal of the FET 245 becomes zero and the FET 245 is turned off. Therefore, even if the switch 21 is pulled, the motor 153 does not rotate. Accordingly, when any event occurs during the rotation of the motor 153, the microcomputer 211 can stop the rotation of the motor 153 by outputting a Low signal to the output stop circuit 243. The output stop circuit 243 has a further FET 251 and an FET 251 for controlling the gate signal of the FET 248 to be grounded by a signal from the switch 55 or the Hall IC 56 included in the connection unit 50 that accommodates the heel expansion / contraction sensor. It is done.

  Diodes 253 and 254 are disposed between the gate of the FET 251 and the switch 55 or the Hall IC 56. Resistors 255 and 256 for determining a reference potential are provided on the signal line from the switch 55 or the Hall IC 56. Here, the switch 55 is turned off when the movable pipe 80 is extended to a predetermined position with respect to the fixed pipe 40, and is turned on when the movable pipe 80 is not extended. Similarly, the potential supplied to the FET 251 via the diode 254, which is the output of the Hall IC 56, becomes Low when the movable pipe 80 extends to a predetermined position with respect to the fixed pipe 40, and when it does not extend. High. By providing the FET 251 in this way, when the movable pipe 80 does not extend to the predetermined position with respect to the fixed pipe 40, the gate signal of the FET 251 becomes High, the output from the output stop circuit 243 is stopped, and the motor 153 is stopped. The power supply stops. As described above, in this embodiment, the microcomputer 211 is configured so that the output stop circuit 243 can be controlled in accordance with the output of the heel expansion / contraction sensor serving as the expansion / contraction detection means, and the output of the heel expansion / contraction sensor is directly output to the output stop circuit. By transmitting to 243, power supply to the motor 153 can be reliably stopped when the bag is contracted from the extended state or contracted during operation. Further, when the signal line 58 is disconnected or when the output result of one of the sensors is different, the microcomputer 211 functions as an abnormality detection unit that detects an abnormal state, so that a Low signal is supplied to the FET 248 via the resistor 249. By doing so, the motor 153 can be stopped.

  The main power automatic stop circuit 203 is a circuit for cutting off the entire power supply of the electric brush cutter 1 under the control of the microcomputer 211. The collector-emitter of the transistor 205 of the main power supply automatic stop circuit 203 is connected to the ground and the gate of the FET 230 via the resistor 204, and the base is connected to the A / D output port of the microcomputer via the resistor 206. When a high signal is output from the microcomputer 211 to the gate of the transistor 205, the collector-emitter of the transistor 205 is brought into conduction, so that a predetermined voltage is applied to the gate of the FET 230, so that the same state as when the main power switch 220 is pressed. Thus, the main power supply is shut off by turning off the transistor 228 which has been turned on until then.

  As described above, according to the circuit configuration of the present embodiment, when the movable pipe 80 does not extend to the predetermined position with respect to the fixed pipe 40, or when the movable pipe 80 is suddenly contracted during work in the extended state. When the signal line 58 is disconnected or when an abnormality such as the output result of one of the sensors is different, the power supply to the motor 153 is immediately stopped. An electric brush cutter having a ridge can be realized.

  Next, the control procedure of the electric brush cutter 1 will be described using the flowchart of FIG. First, when the battery pack 2 is attached to the battery attachment portion 11a and the main power switch 220 is turned on, power is supplied to the microcomputer 211, and the microcomputer 211 is activated. Then, the microcomputer 211 performs a predetermined initial setting by executing the stored startup program (step 261). Next, the microcomputer 211 outputs a Low signal to the FET 248 to shut off the source and drain of the FET 245 so that power is not output to the motor 153 (step 262). This step is to prevent a malfunction that the main power switch 220 is turned on while the trigger lever 44 is pulled and the rotation of the cutting blade 155 suddenly starts. Next, the microcomputer 211 detects whether the movable pipe 80 is fully extended with respect to the fixed pipe 40, that is, whether it is in the extended state when trimming as shown in FIG. Is executed (step 263).

  Here, the detailed procedure of the eyelid expansion / contraction detection routine will be described with reference to the flowchart of FIG. In this subroutine, the microcomputer 211 executes computer software to make a determination using the output results of the Hall IC 56 as a magnetic sensor and the mechanical switch 55. First, the microcomputer 211 determines whether the output of the Hall IC 56, which is a magnetic sensor, is Low (step 291). The low output of the Hall IC 56 indicates that the heel state is in the extended state (the state shown in FIGS. 1 and 4). If the output of the Hall IC 56 is Low, then the mechanical type It is detected whether or not the output of the switch 55 is Low (blocking state) (step 292). When the output of the switch 55 is Low, it indicates that the heel state is in the extended state (the state shown in FIGS. 1 and 4). Therefore, in Step 292, the outputs of the two heel expansion / contraction sensors coincide with each other. Accordingly, the microcomputer 211 determines that the heel is in the extended state (step 293), ends the heel extension / contraction detection routine, and returns to the flow of FIG.

  If the output of the Hall IC 56 is High in Step 291, it can be determined that the wrinkle is in a shortened state by detection by the Hall IC 56, so whether or not the output of the mechanical switch 55 is Low (cut-off state) next. Is detected (step 294). Here, when the output of the switch 55 is High, the switch 211 detects that the heel is in a shortened state, and the microcomputer 211 determines that the heel is in a shortened state by matching the outputs of the two heel expansion / contraction sensors ( Step 296), the wrinkle expansion / contraction detection routine is terminated, and the flow returns to the flow of FIG. If the output of the switch 55 is high in step 292, or if the output of the switch 55 is low in step 294, the outputs of the two eyelid expansion / contraction sensors do not match, so the microcomputer 211 is in either expansion / contraction state. It is determined that the sensor is abnormal (step 295), the wrinkle expansion / contraction detection routine is terminated, and the flow returns to the flow of FIG.

  FIG. 10 is a table showing combinations of the outputs of the switch 55 and the magnetic sensor (Hall IC 56) based on the determination result shown in the flowchart of FIG. 9. In the combination state shown in FIG. Elongation) ”. As can be understood from this figure, the switch 55 is not recognized as being in the extended state unless it is in the closed state. This means that the motor 153 does not rotate when the switch 55 is open for some reason such as disconnection of the signal line 58 or failure of the switch 55. Since both the switch and the output of the magnetic sensor are configured to be High when shortened, the outputs are triggered without the microcomputer 211 (signals via the diodes 253 and 254 in FIG. The output stop circuit 243 can be directly controlled to stop the rotation of the motor.

  Returning again to step 264 of the flowchart of FIG. In step 264, the microcomputer 211 determines whether an abnormality has occurred in the detection results of the two expansion / contraction sensors. If the occurrence of an abnormal state is detected in step 295 of the flow of FIG. 9, the process proceeds to step 277 where the microcomputer 211 outputs a high signal to the main power automatic stop circuit 203. As a result, the main power supply automatic stop circuit 203 shuts off the main power supply in order to cancel the main power switch on state of the main power switch circuit 214, and the electric brush cutter 1 stops.

If there is no abnormality in the detection results of the two expansion / contraction sensors in step 264, it is determined whether or not the heel is in an extended state (step 265), and it is determined in step 296 in FIG. 10 that the heel is in a shortened state. If so, the process returns to step 263 and waits until the bag is extended. When the heel is in the extended state in step 265, it is determined whether or not the switch 21 is turned on at that time (step 266). Here, the fact that the switch 21 is on means, for example,
(1) When the heel is lifted without being stretched, it is stretched by the weight of the motor at the tip, (2) When the heel is stretched while the trigger lever is pulled by an obstacle, etc. Can be envisaged. Therefore, the motor 153 is prevented from rotating unless the microcomputer 211 has confirmed that the one end switch 21 is turned off after extending the hook in step 265. Here, when the trigger lever 44 is opened after extending the heel in the above-described series of steps, the microcomputer determines whether a predetermined time has elapsed (step 267), and returns to step 266 if not. This is a safety mechanism for preventing the motor 153 from starting immediately after extending the bag, and waits for about one tempo (0.5 to 3 seconds) as a predetermined time.

  If the predetermined time has elapsed in step 266, that is, if the predetermined time has elapsed with the trigger lever 44 released, the eyelid expansion / contraction detection routine shown in the flowchart of FIG. 9 is executed again (step 268). Next, the microcomputer 211 determines whether or not there is an abnormality in the expansion / contraction sensor based on the execution result of the eyelid expansion / contraction detection routine (step 269). If there is an abnormality, the microcomputer 211 stops the output of power to the motor 153 by outputting a Low signal to the output stop circuit 243 (step 278), and outputs a High signal to the main power supply automatic stop circuit 203. To shut off the main power supply (step 279) and stop the electric brush cutter 1 as a whole.

  If there is no abnormality in the detection results of the two expansion / contraction sensors in step 269, it is determined whether or not the heel is in the extended state (step 270). If the heel is not in the extended state, the microcomputer 211 outputs the output stop circuit. By outputting the Low signal to 243, the output of electric power to the motor 153 is stopped to stop the rotation if the motor is rotating (step 280). If the switch 21 remains on, the process returns to step 280 to maintain the motor 153 stopped, and if the switch 21 is off, the process returns to step 268 (step 281). As described above, in this embodiment, since the bag can be expanded and contracted, the microcomputer 211 keeps the motor 153 in a stopped state until the switch 21 is securely turned off when the bag is out of the extended state. The safety is further improved.

  If it is determined in step 270 that the heel is extended, it is determined whether or not the switch 21 is turned on by the operator (step 271). If the switch 21 is on, the microcomputer 211 outputs a High signal to the output stop circuit 243 to permit the drive current to be supplied to the motor 153 (step 272). As a result, since the electric power from the battery pack 2 is supplied to the motor 153 via a booster circuit (not shown), the motor 153 rotates at the rotation speed set by the dial 20, and the operator cuts grass or the like. Work can be done. Next, the microcomputer 211 determines from the output of the battery voltage detection circuit 235 whether the battery is in an overdischarged state, that is, whether the battery voltage has dropped, and if not, returns to step 268 (step 273). The overdischarge here means a state in which the battery is empty. In step 268, a current detection circuit (not shown) is used to monitor the value of the current flowing through the motor 153, and in the case of overcurrent, the process proceeds to step 274. You may comprise so that it may do.

  If the switch 21 is OFF in step 271 or overdischarge is detected in step 273, the microcomputer 211 outputs a low signal to the output stop circuit 243 to stop the output of power to the motor 153, thereby causing the motor. Is stopped (step 280). Next, the microcomputer 211 determines from the output of the battery voltage detection circuit 235 whether or not the battery is overdischarged. If not, the microcomputer 211 returns to step 268 (step 275). If overdischarge occurs, the main power supply automatic stop circuit 203 is returned. The main power supply is shut off by outputting a high signal (step 276), and the entire electric brush cutter 1 is stopped.

  By controlling as described above, the motor 153 is driven to rotate. If it is detected in step 271 that the switch 21 has been returned during this time, or the battery pack 2 is in an overdischarged state in step 273. Is detected, the output of power to the motor 153 is stopped (step 274). Next, the microcomputer 211 determines whether or not the battery is in an overdischarged state from the output of the battery voltage detection circuit 235 (step 275). If the battery is in the overdischarged state, the microcomputer 211 outputs a High signal to the main power supply automatic stop circuit 203. Thus, the main power supply is shut off and the electric brush cutter 1 is stopped (step 276). If it is not overdischarged in step 275, the process returns to step 268.

  As described above, by performing the control of the flowchart shown in FIG. 8 using the microcomputer 211, when the movable pipe 80 does not extend to the specified position, the motor 153 is not energized from the battery pack 2. Does not rotate. Further, even when the movable pipe 80 extends to the specified position while the trigger lever 44 is pulled, the motor 153 does not start suddenly. Furthermore, even if the movable pipe 80 contracts from the specified position for some reason during the rotation of the motor 153 and enters a non-extended state, the energization to the motor 153 is immediately cut off, so the safety is high. The electric brush cutter 1 having a telescopic fold can be realized.

  Next, a circuit diagram according to a second embodiment of the present invention will be described with reference to FIG. The controller 301 of the second embodiment is mounted on the circuit board 13 shown in FIG. 3. The configuration and components other than the electric circuit mounted on the circuit board 13 are the same as those of the first embodiment. Exactly the same as shown. In the controller 301, the switch 21, the main power switch circuit 214, the main power automatic stop circuit 203, the constant voltage circuit 207, the battery voltage detection circuit 235, the trigger detection circuit 240, and the microcomputer 211 are the same as those in the first embodiment. The repetitive description of their internal configuration and operation will be omitted. The output stop circuit 343 receives a stop signal from the microcomputer 211 (High signal to the gate of the FET 348), and the source-drain of the FET 345 is cut off. The output stop circuit 243 (first embodiment) The operation is basically the same as that shown in FIG. However, in the output stop circuit 343 of the second embodiment, the source and drain of the output stop FET 345 are directly cut off in accordance with the output from the heel expansion / contraction sensor (connector 50) (diodes 253 and 254 in FIG. 7). FET 251 and resistor 252) are not included. Since this configuration is not unnecessary in the second embodiment, these may be added to the circuit of FIG.

  In the second embodiment, the controller 301 is provided with an electronic brake circuit 360. The electronic brake circuit 360 is configured to brake the rotation of the motor 153 with a predetermined strength (braking force weaker than that of the sudden brake) by intermittently controlling a brake current flowing through the motor 153. The motor 153 used in this embodiment is a coreless motor, and even if the current supplied to the motor 153 is cut off, the motor 153 rotates due to inertia. Therefore, an electronic brake circuit 360 is provided to brake the motor 153 by supplying a current that acts to brake the motor 153, that is, a brake current. The electronic brake circuit 360 basically includes a brake FET 373 for short-circuiting the + terminal and the − terminal of the motor 153, and four FETs 361, 364, 368, 370 for driving the FET 373. The brake FET 373 is preferably a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), for example, and the conduction state between the source and the drain is controlled by a signal from the microcomputer 211.

  First, when a high signal for applying an electric brake is issued from the microcomputer 211, the signal is input to the gate signals of the FETs 361 and 364 via the resistor 362. The gates of the FETs 361 and 364 are grounded via the resistor 363, and the FETs 361 and 364 are simultaneously turned on (in a state where the source and the drain are in conduction) by the High signal from the microcomputer 211. When the drains of the FETs 361 and 364 are turned on, that is, become High, the FET 368 is turned on and the FET 370 is turned off. When the FET 368 is turned on and the FET 370 is turned off, a predetermined voltage is applied to the gate of the brake FET 373 via the resistor 371, so that the source and drain of the FET 373 are turned on. Since the source of the FET 373 is connected to the + terminal of the motor 153 and the drain thereof is connected to the − terminal, the ON between the source and drain of the FET 373 means a short circuit of the + − terminal of the motor 153 and the brake is applied.

  When the motor 153 is short-circuited, it is braked rapidly and its rotation is rapidly reduced. When it is desired to stop the motor 153 in an emergency or when the expansion / contraction of the kite is detected for some reason, it is preferable to maintain the short-circuit state of the motor 153 and perform rapid braking. However, when the trigger lever 44 is released, it may be preferable not to apply the brake suddenly but to stop the rotation of the motor 153 after one tempo delay or slowly. For example, an operator who is performing a brushing operation grips the grip portion 43 of the handle pipe 42 and moves the cutting blade 155 left and right by the handle pipe 42. When moving the handle pipe 42 to the left and right, Otherwise, the trigger lever 44 may be released. If the motor 153 stops suddenly at such a time, the work may be hindered. Therefore, in this embodiment, the microcomputer 211 is configured to control the strength and timing at which the brake is applied.

  If the output from the microcomputer 211 changes from High to Low while the brake is operating, that is, between the source and drain of the FET 373, the Low signal is input to the gate signals of the FETs 361 and 364 via the resistor 362 and the FET 361. And 364 are turned off (the state where the source and the drain are not conducting). When the FETs 361 and 364 are turned off, the FET 368 is turned off, but the FET 370 is turned on because a predetermined voltage is applied to the gates by the resistors 366 and 369. As a result, since the gate signal of the FET 373 becomes Low, the source-drain of the brake FET 373 is turned off, and the brake (the short circuit state of the motor 153) is released. In this embodiment, the motor 153 can be softly braked by switching the brake instruction signal from the microcomputer 211 at high speed between High and Low. This switching braking can use, for example, PWM control, and details will be described later.

  The output voltage detection circuit 390 is a circuit for measuring the voltage between the terminals of the motor 153, and is composed of a series circuit of a voltage dividing resistor 391 and a voltage dividing resistor 392. One end of the voltage dividing resistor 391 is a microcomputer 211. To the A / D input terminal. Although not disclosed in FIG. 11, the circuit board 13 (see FIG. 3) is provided with a booster circuit for driving the motor 153, and the rotation speed of the motor 153 is controlled by changing the output voltage from the booster circuit. To do. For this purpose, the output voltage to the motor 153 is fed back. In addition, when the motor 153 rotates by inertia when the brake is applied, the battery voltage detection circuit 235 cannot detect the back electromotive force generated by the motor 153. Therefore, the output voltage detection circuit 390 is separately provided.

  The microcomputer 211 executes a program stored in the memory in advance, thereby obtaining a current flowing in the motor 153 detected by a current detection circuit (not shown) and a voltage output from the battery pack 2 detected by the battery voltage detection circuit 235. The main power switch circuit 214 is turned off when the current flowing through the motor 153 exceeds the rating of the motor 153 or when the voltage output from the battery pack 2 becomes lower than a predetermined value. In addition, the microcomputer 211 automatically turns off the main power switch circuit 214 when it detects that the main power switch circuit 214 is turned on but power is not supplied to the motor 153 for a certain period of time. Battery information is input to the microcomputer 211 from an input terminal (ID terminal) (not shown). When the battery information is input, the microcomputer 211 refers to a table stored in advance in an internal memory and reads a voltage at which the battery is overdischarged from the battery information. For example, the microcomputer 211 sets the overdischarge voltage to 8 V if the battery information includes information of a rating of 14.4 V, and sets the overdischarge voltage to 10 V if the rating is 18 V. The microcomputer 211 automatically turns off the main power switch circuit 214 when the output voltage of the battery pack 2 falls below the overdischarge voltage.

  The battery voltage detection circuit 235 outputs a voltage proportional to the voltage output from the battery pack 2 to the microcomputer 211 by measuring the voltage output from the main power switch circuit 214. When the output voltage of the battery pack 2 detected by the battery voltage detection circuit 235 becomes an abnormal value, the microcomputer 211 turns off the main power switch circuit 214 and stops the output of the battery pack 2. Thereby, it is possible to prevent the battery pack 2 from being overdischarged.

  In addition, when the voltage is inputted to the microcomputer 211 from the battery voltage detection circuit 235 and the output from the current detection circuit (not shown) is not inputted, the main power switch is automatically turned on when a certain period stored in the memory is exceeded. The circuit 214 is turned off. As a result, the power of the electric brush cutter 1 can be automatically turned off, for example, when the main power switch circuit is on and the electric brush cutter 1 is left unattended.

  The display circuit 380 is a circuit that turns on the LED 381 with a low-voltage direct current generated by the constant voltage circuit 207, and includes a current limiting resistor 382 connected in series to the LED 381. The lighting of the LED 381 is controlled by the microcomputer 211. The LED 381 is a red light emitting diode disposed on the upper side of the cord stopper 12. The LED 381 is lit in a normal state (no abnormality), slowly blinks in an overdischarged state of the battery, and other abnormal states (motors due to shortening of the eyelids). In the case of stop, etc., it functions as a notification means for the operating state and error state for the worker by flashing quickly. Note that when the main power supply is cut off by the microcomputer 211, the current supplied to the display circuit 380 is also cut off, so that the LED 381 is turned off.

  Next, the control procedure of the second embodiment of the present invention will be described using the flowchart of FIG. The flowchart of FIG. 12 is obtained by adding an electric brake function and a display lamp function to the flowchart of the first embodiment described in FIG. 8, and the basic control flow is the same. First, when the battery pack 2 is attached and the main power switch 220 is turned on, the microcomputer 211 is activated and executes a startup program to perform predetermined initial settings (step 401). Next, the microcomputer 211 shuts off the source and drain of the FET 245 and keeps the rotation of the motor 153 stopped (step 402). Next, the microcomputer 211 turns on the LED 381 by supplying current to the display circuit 380 (step 403). The lighting state may be continuous lighting that displays the normal state.

  Here, the lighting state of the LED 381 will be described with reference to the table of FIG. In this embodiment, one red light emitting diode is used as the LED 381, and the lighting state is changed to notify the operator. The LED 381 is continuously lit (normal display) when the main power switch 220 is in a normal state. When the remaining amount of the battery pack 2 becomes less than a predetermined value, that is, in the overdischarge state, the LED 381 blinks at a slow speed (overdischarge display). This slow blinking allows the operator to know that the work cannot be continued unless the battery pack 2 is charged or replaced. In this embodiment, an “abnormal display” is further provided that causes the LED 381 to blink at a high speed. This is displayed when the signals from the plurality of eyelid expansion / contraction detection means do not match, so that the operator can know that the electric brush cutter 1 has failed.

  Returning again to the flowchart of FIG. In step 404, the microcomputer 211 determines whether the movable pipe 80 is in an extended state with respect to the fixed pipe 40, that is, whether it is in an extended state when trimming as shown in FIG. Execute. The routine shown in step 404 may use the same subroutine as the procedure described in FIG. Next, the microcomputer 211 determines whether or not an abnormality has occurred in the detection results of the two expansion / contraction sensors (step 405). If the occurrence of an abnormal state is detected, the microcomputer 211 proceeds to step 418, and the microcomputer 211 causes the LED 381 to blink rapidly indicating “abnormal display”. This “abnormal display” is performed for a predetermined time (step 419), and then the microcomputer 211 automatically stops the main power supply by outputting a High signal to the main power supply automatic stop circuit 203 (step 420). As a result, the operation of the electric brush cutter 1 is stopped.

  If there is no abnormality in the detection results of the two expansion / contraction sensors in step 405, it is determined whether or not the heel is in the extended state (step 406). If it is determined that the heel is in the shortened state, the microcomputer 211 sends a high signal to the electronic brake circuit 360 to brake the motor 153 (step 421). Next, the process returns to step 404 and waits until the bag is extended. When the kite is in the extended state in step 406, the microcomputer 211 sets the signal sent to the electronic brake circuit 360 to low to release the brake operation (step 407), and determines whether or not the switch 21 is on (step 407). Step 408). If the switch 21 is off, the microcomputer 211 determines whether a predetermined time has elapsed (step 409). If not, the microcomputer 211 returns to step 408.

  If the predetermined time has elapsed in step 409, the microcomputer 211 sets the signal sent to the electronic brake circuit 360 to low to release the brake operation (step 410), and executes the kite expansion / contraction detection routine shown in the flowchart of FIG. Execute (step 411). Next, the microcomputer 211 determines whether or not there is an abnormality in the expansion / contraction sensor based on the execution result of the eyelid expansion / contraction detection routine (step 412). If there is an abnormality, the microcomputer 211 outputs a low signal to the output stop circuit 343 to stop the output of electric power to the motor 153 (step 433), and sends a high signal to the electronic brake circuit 360 for braking. Is turned on (step 434), and the LED 381 is "abnormally displayed", that is, displayed for a predetermined time by blinking at an early interval (steps 435 and 436). When the predetermined time has elapsed, the microcomputer 211 outputs a High signal to the main power automatic stop circuit 203 to shut off the main power (step 437) and stop the electric brush cutter 1.

  If there is no abnormality in the detection results of the two expansion / contraction sensors in step 412, it is determined whether or not the heel is in the extended state (step 413). If the heel is not in the extended state, the microcomputer 211 outputs an output stop circuit. A Low signal is output to 343 to stop the rotation of the motor 153 (step 429). Further, the brake is turned on by sending a high signal to the electronic brake circuit 360 (step 430), and the LED 381 is displayed as "abnormal display", that is, blinking at a fast interval for a predetermined time (step 431). If the switch 21 remains on, the process returns to step 429 to maintain the motor 153 stopped, and if the switch 21 is off, the process returns to step 411 (step 432). As described above, in this embodiment, since the bag can be expanded and contracted, the microcomputer 211 keeps the motor 153 stopped until the switch 21 is reliably turned off when the bag is out of the extended state.

  If it is determined in step 413 that the heel is extended, it is determined whether or not the switch 21 is turned on by the operator (step 414). When the switch 21 is on, the microcomputer 211 sets the output level to the electronic brake circuit 360 to Low to turn off the brake (step 415), and outputs a High signal to the output stop circuit 243, thereby driving the motor 153. Current is output (step 416). As a result, since the electric power from the battery pack 2 is supplied to the motor 153 via a booster circuit (not shown), the motor 153 rotates at the rotation speed set by the dial 20. Next, the microcomputer 211 determines whether or not the battery is in an overdischarged state from the output of the battery voltage detection circuit 235 (step 417), and returns to step 411 if not in an overdischarged state.

  By controlling as described above, the motor 153 is driven to rotate. If it is detected in step 414 that the switch 21 has been returned during this time, or the battery pack 2 is overdischarged in step 417. Is detected, the output of electric power to the motor 153 is stopped (step 423), and the brake is turned on by sending a high signal to the electronic brake circuit 360 (step 424). Next, the microcomputer 211 determines whether or not the battery is in an overdischarge state from the output of the battery voltage detection circuit 235 (step 425), and if not, returns to step 411. If it is in the overdischarged state, the microcomputer 211 displays the LED381 as “overdischarge display”, that is, blinking at a slow interval for a predetermined time (steps 426 and 427). When the “overdischarge display” is performed for a predetermined time, the microcomputer 211 outputs a High signal to the main power automatic stop circuit 203 to shut off the main power and stop the electric brush cutter 1 (step 428). Note that the brake (soft brake) in step 424 does not need to be braked suddenly, unlike the brake (sudden brake) when the expansion / contraction of the kite is detected or some abnormality occurs. On the other hand, for an operator who has a habit of inadvertently releasing the trigger lever 44 during work, it is preferable to set the brake in step 424 to be soft braking (braking with weakness) rather than sudden braking. Therefore, in step 424, a high signal is intermittently sent from the microcomputer 211 to the electronic brake circuit 360 so that the strength of the brake is positively controlled. Thus, by controlling the time interval at which the High signal is sent to the electronic brake circuit 360 at every time interval, the brake condition can be adjusted. Since this adjustment can be controlled by software by the microcomputer 211, highly accurate brake control can be performed.

  FIG. 13 is a flowchart showing the procedure of electronic brake control in step 424. These procedures can be controlled in software by the microcomputer 211 executing a computer program. First, the microcomputer 211 determines whether or not the output voltage (back electromotive force generated by the motor 153) detected by the output voltage detection circuit 390 is 5% or less (step 461). This is because if the motor 153 is decelerated so that the back electromotive force becomes 5% or less, the motor 153 stops immediately, and it is not necessary to apply an electronic brake. If the output voltage is 5% or less, the microcomputer 211 sets the output level to the electronic brake circuit 360 to Low, turns off the brake (Step 474), and returns to Step 424 in FIG. If the output voltage is greater than 5%, the microcomputer 211 uses a timer included therein to start a timer for delaying the brake application timing (step 462). In this way, the electronic brake is not applied immediately, but the brake is started after being delayed by one tempo because the trigger lever 44 is frequently released while swinging the heel to the left and right during the mowing operation. This is because when there is an operator who has such an operation, even if such an operation is performed, it is not jerky. The time for delaying the one tempo may be about 0.3 to several seconds, for example, 1 second or 1.5 seconds.

  Next, the microcomputer 211 determines whether or not the trigger lever 44 is turned on (step 463), and if the trigger lever 44 remains off, determines whether or not the set delay time has elapsed. If not, the process returns to step 463 (step 464). If the operator pulls the trigger lever 44 again in step 463, that is, if there is no intention to apply the brake, it is determined whether or not the kite is extended (step 475). It is determined whether or not the pack 2 is in an overdischarged state (step 476). If the bag is in a contracted state at steps 475 and 476, or if the battery pack 2 is overdischarged, the routine proceeds to step 464 and the electronic brake is continued. If the battery pack 2 is not over-discharged in step 475 when the battery pack 2 is not overdischarged, it means that the operator intends to continue the work, not the intention to apply the brake, so the brake delay timer is cleared. (Step 477), the process returns to Step 424 in FIG.

  Next, when a predetermined delay time elapses in step 464, the microcomputer 211 clears the brake delay timer (step 465), and turns on the brake by sending a high signal to the electronic brake circuit 360 (step 466). At this time, PWM control of the brake signal sent from the microcomputer 211 is performed, and driving is performed with a duty ratio of 10% (step 466). FIG. 14 is a diagram for explaining the PWM control method. FIG. 14 (1) is a diagram for explaining the control situation with a duty ratio of 10% driven in step 466. The brake signal 491 is a signal sent from the microcomputer 211 to the electronic brake circuit 360. As can be understood from FIG. 11, the brake signal is supplied to the gate signals of the FETs 361 and 364 via the resistor 362. The PWM control of the brake signal with a duty ratio of 10% means that the electronic brake is applied by sending a High signal for a time corresponding to 10% in units of 100 μsec, that is, for 10 μsec. For the remaining 90 μs, the signal sent from the microcomputer to the electronic brake circuit 360 is set to Low. The frequency of PWM control at this time is 10 KHz, and this control is repeated. Note that the duty ratio of the PWM control can be arbitrarily changed between 0% and 100%. FIG. 14 (2) shows the brake signal 492 when the duty ratio is 50%. The brake signal 491 is PWM-controlled with a duty ratio of 50%, and the electronic brake is applied by sending a High signal for a time corresponding to 50% of the 100 μs unit, that is, for 50 μs. For the remaining 50 μs, the signal sent from the microcomputer to the electronic brake circuit 360 is set to Low.

  Returning again to step 466 of FIG. Next, the microcomputer 211 determines whether or not the trigger lever 44 is turned on (step 467). If the trigger lever 44 remains off, the output voltage detected by the output voltage detection circuit 390 is 15% or less. If it has not decreased, the process returns to step 467 (step 468). If the operator pulls the trigger lever 44 again at step 467, that is, if there is an intention to release the brake, it is determined whether or not the heel is extended (step 478). It is determined whether or not the pack 2 is in an overdischarged state (step 479). If the bag is in a contracted state in steps 478 and 479, or if the battery pack 2 is overdischarged, the routine proceeds to step 468 and the electronic brake is continued. If the battery pack 2 is not over-discharged in step 478 when the bag is extended, it means that the operator intends to continue the work, not intending to apply the brake, so the brake is turned off (step 480). ), The process returns to step 424 in FIG.

  If the output voltage drops to 15% or less in step 468, the operating condition of the electronic brake is reduced due to the voltage drop, so the duty ratio of the PWM control is increased, but before that, it is detected by the output voltage detection circuit 390. It is determined whether the output voltage (back electromotive force by the motor 153) is 5% or less (step 469). Here, if the motor 153 is decelerated to 5% or less, the motor 153 stops immediately. Therefore, the microcomputer 211 sets the output level to the electronic brake circuit 360 to Low and turns off the brake (step 481). Return to step 424. If the speed is not reduced to 5% or less at step 469, the microcomputer 211 controls the brake to be strongly applied with a duty ratio of 50% as shown in FIG. 14 (2) (step 470).

  Next, the microcomputer 211 determines whether or not the trigger lever 44 is turned on (step 471). If the trigger lever 44 remains off, the output voltage detected by the output voltage detection circuit 390 is 5%. It is determined whether or not it has decreased below. If not, the process returns to step 471 (step 472). If the operator pulls the trigger lever 44 again in step 471, that is, if there is an intention to release the brake, it is determined whether or not the kite is extended (step 482). It is determined whether or not the pack 2 is in an overdischarged state (step 483). If the bag is in a contracted state in steps 482 and 483, or if the battery pack 2 is over-discharged, the routine proceeds to step 472 and the electronic brake is continued. If the battery pack 2 is not overdischarged in step 482 when the bag is extended, it means that the operator intends to continue the work, not the intention to apply the brake, so the brake is turned off (step 484). ), The process returns to step 424 in FIG. If the output voltage drops to 5% or less in step 472, the microcomputer 211 sets the output level to the electronic brake circuit 360 to low, turns off the brake (step 473), and returns to step 424 in FIG.

  As described with reference to the flowchart of FIG. 13, according to the second embodiment, an electronic brake circuit 360 that is PWM-controlled by the microcomputer 211 is provided, and the brake is softly applied at the required strength at the required timing. Therefore, it is possible to prevent a reduction in the life of the motor due to a sudden start and stop of the motor and unnecessary consumption of the battery pack. In FIG. 13, the duty ratio of PWM control is set to 10% and 50%. However, the duty ratio is not limited to this, and a plurality of duty ratios may be arbitrarily selected or used continuously.

  Although the present invention has been described using the two embodiments, the present invention is not limited to the above embodiments, and various modifications and applications are possible. For example, in the above embodiment, the fixed pipe 40 and the movable pipe 80 constituting the bag are described as being substantially cylindrical pipes. However, if the telescopic electric wires supplied to the motor 153 from the operation unit 10 can be disposed inside, the shape can be obtained. It is not necessary to stick to the cylindrical shape, and the cross section may have another shape, for example, a quadrangle or a polygon. Further, the method of fixing the movable pipe 80 in the connecting portion 50 is not limited to the fixing method using the fixing lever 62 as in the above-described embodiment, but the movable pipe 80 is fixed to the fixed pipe using other known fixing methods. You may fix so that it may not move to an axial direction with respect to 40. FIG. Furthermore, the two expansion / contraction detection means arranged in the connection unit 50 are not limited to the switch 55 and the Hall IC 56, but may be configured using other arbitrary sensors and switches.

  In the above-described embodiment, the LED 381 for displaying the operation state displays the capacity reduction state of the battery pack 2, the abnormality of the expansion / contraction state of the bag, and the abnormality of the expansion / contraction detection unit of the bag. These states may not be displayed only by the difference in state, but may be displayed separately by the LED display color, or may be displayed by providing a plurality of LEDs. Further, a liquid crystal display panel may be provided on the operation panel 16 to display detailed information, or a speaker or a buzzer may be provided to generate a sound to notify the operator.

  Moreover, although the example applied to the electric brush cutter as an example of the electric working machine has been described in the above embodiment, the present invention is not limited to the brush cutter, and the working device driven by the motor at the tip of the telescopic hook is provided. The present invention can be similarly applied to the electric work equipment provided. For example, as shown in FIGS. 16 (1) to (4), an electric working machine in which various working devices are attached to the tip of the movable pipe 80 instead of the driving unit 151 is conceivable. FIG. 16 (1) is an example in which a hedge trimmer drive unit 551 is attached to the tip of the movable pipe 80. The hedge trimmer drive unit 551 is provided with a cutting blade 555 that reciprocates in the front-rear direction, so that the work of trimming grass and branches can be performed. FIG. 16B is an example in which a pole saw hedge trimmer drive unit 651 is provided at the tip of the movable pipe 80. In the pole saw hedge trimmer driving unit 651, a small saw chain 655 rotates, so that a branch cutting operation or the like can be performed. FIG. 16 (3) is an example in which a cultivator driving unit 751 is provided at the tip of the movable pipe 80. The cultivator driving unit 751 can perform the work of plowing the topsoil by rotating several claws 755. FIG. 16 (4) is an example in which an edger driving unit 851 is provided at the tip of the movable pipe 80. The edger driving unit 851 can perform an operation of aligning grass edges and the like with the rotating cutting blade 855. In addition, in the electric working machine of the present invention, if the driving unit for performing various work is provided at the tip of the rod and the driven object is operated by a motor, the type of the work is the example described above. It is not limited to.

DESCRIPTION OF SYMBOLS 1 Electric brush cutter (electric working machine) 2 Battery pack 3 Fixed part 4 Movable part 10 Operation part 11 Housing 11a Battery mounting part 12 Code stopper 13 Circuit board 14 Terminal base 15 Terminal 16 Operation panel 17 Lead wire 18 Power line 20 Dial 21 Switch 22 Plunger 23 Movable plate 26 Wire 26a Wire end 27 Bellows tube 28 Lumbar support part 29 Coil 30 Connection terminal 31, 32 Capacitor 33 Fixing tool 34 Mounting boss 34a Abutting surface 35 Curl cord 35a Spring part 35b End part 40 Fixed pipe 41 Handle portion 42 Handle pipe 43 Grip portion 44 Trigger lever 45 Lock lever 46 Handle holder 47 Belt holder 50 Connection portion 51 Holder 51a Spring plate 51b Switch box 51c Signal line guide portion 51d Spring accommodating portion 52 Stopper 53 Sleeve 53a Recessed portion 53b Inclined surface 53c Hook portion 54 Magnet 55 Switch 55a Lever 55b Pulley 56 Hall IC 58 Signal wire 59a to 59g Screw boss 60 Ball 61 Spring 62 Fixed lever 63 Bolt 66 Center 80 (of fixed lever swing) Movable pipe 80a Drilled hole 80b Through hole 80c Rail portion 151 Drive portion 152 Motor case 153 Motor 154 Fan cover 155 Cutting blade 156 Holder 153 Motor 155 Cutting blade 170 Scatter protection cover 201 Controller 203 Main power automatic stop circuit 204 Resistor 205 Transistor 206 Resistor 207 Constant voltage circuit 208, 210 Capacitor 209 Three-terminal regulator 211 Microcomputer 214 Main Source switch circuit 215, 217, 218, 222-225, 227, 229, 231 Resistor 216 Diode 219 Capacitor 220 Main power switch 221, 226, 228 Transistor 230 FET 235 Battery voltage detection circuit 236, 237 Voltage dividing resistor 238 Transistor 240 Trigger detection circuit 241, 242 Voltage dividing resistor 243 Output stop circuit 245, 248, 251 FET
246, 247, 249, 250, 252 Resistor 253, 254 Diode 255 Resistor 257 Diode 301 Controller 343 Output stop circuit 345, 348 FET
346, 347, 349, 350 Resistors
360 Electronic brake circuit 361, 364, 368, 370, 373 FET
362, 363, 365, 366, 367, 369, 371, 372 Resistor 380 Display circuit 381 LED
382 Resistor 390 Output voltage detection circuit 391, 392 Voltage dividing resistor 491, 492 Brake signal 551 Hedge trimmer drive unit 555 Cutting blade 651 Pole saw hedge trimmer drive unit 655 Saw chain 751 Cultivator drive unit 755 Claw 851 Edger drive unit 855 Cutting blade 1001 Electric Brush cutter 1002 Battery pack 1003 Operation unit 1004 Motor unit 1005 Cutting blade 1006 竿 1007 Handle pipe 1008a, 1008b Grip unit 1009 Trigger lever 1010 Dial 1011 Scatter protection cover 1012 Lumbar support member

Claims (6)

A motor, a fixed portion provided with a handle having a grip portion, a movable portion that is slidably held by being extended with respect to the fixed portion, a trigger switch for rotating the motor, and rotation of the motor A control unit for controlling
The movable part is an electric working machine having a cutting blade driven by the motor at the tip of a movable pipe connected to the fixed part,
A detecting unit connected to the control unit and detecting whether the movable unit is positioned at a predetermined extension position with respect to the fixed unit;
During the rotation of the motor and the control unit by the trigger switch is turned on, the a trigger switch ON state is released by the action of braking force to the motor, and the movable I by the said detection means An electric working machine characterized in that when it is detected that the part is retracted from the extended position, a braking force is applied to the motor even when the trigger switch is in an ON state . Electric working machine of claim 1, the action of the previous SL braking force is characterized by being electrically controlled by the control unit. Wherein the control unit, the trigger switch in the ON state is canceled and the detecting means according to the detection result, thereby continuing the action of the braking force the movable portion from the non-extended position is not in the extended position to switch to the extended position The electric working machine according to claim 2. Providing an informing means for indicating a driving state of the motor;
The electric working machine according to claim 3 , wherein an alarm is issued by the notification means while the controller continues to brake the motor.   The electric working machine according to claim 4, wherein the notification means is a display lamp, and the alarm is lighting or blinking of the display lamp. Wherein, after the released ON state of the trigger switch and said detecting means according to the detection result is switched to the extended position from the non-extended position, the rotation of the motor when it is drawn is the trigger switch again The electric working machine according to any one of claims 3 to 5, wherein the electric working machine is restarted.

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