power tools

Abstract

To provide a power tool structured to be highly safe while enhancing reliability of machining work.SOLUTION: A power tool 1 comprises: a body 2 having an electric motor 7a, a feed screw 8a, a slide 9, and a control unit 19; and a tool head 3 having first and second jaws 11 and 12 connected to the body 2 and rotatably connected to each other, and is configured such that the slide 9 is retracted to a position allowing machining of a workpiece to machine the workpiece, and then the slide 9 is moved forward to a position allowing removal of the machined workpiece. The control unit 19 is configured to determine that the machining of the workpiece is normal to perform a process to be continued next when a detected value of a current sensor 29 is over a first current value U1 while the detected value is not over a second current value U2 at the time of operating a lower limit switch 25, and to determine an abnormality to perform an abnormality process when the second current value U2 is exceeded at the time of operating the lower limit switch 25.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a power tool for machining a workpiece.

Background Art

[0002] Conventionally, a power tool having a configuration in which a crank-type gripping lever and an electric motor are combined is known (Patent Document 1: European Patent No. 2872293). In the power tool of Patent Document 1, in the initial state, the tip side of the tool head is open, and the tip side of the tool head is closed by the gripping force of the operator gripping the gripping lever to sandwich the workpiece, and when the gripping force exceeds a specified value, the electric motor operates and the tip side of the tool head closes to machine the workpiece.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When crimping a crimp terminal and an electric wire at a work site, alignment between the crimp terminal and the electric wire is required. Also, when compressing a compression sleeve to join electric wires to each other at a work site, alignment between the compression sleeve and each electric wire is required.

[0005] However, in the power tool of Patent Document 1, while maintaining a state of gripping the gripping lever connected to one jaw portion with a gripping force within a range not exceeding a specified value, alignment between the crimp terminal and the electric wire and alignment between the compression sleeve and the electric wire must be performed. Therefore, structurally, the balance between the external force applied to one jaw portion and the external force applied to the other jaw portion is likely to be disrupted, and the load on the electric motor is large. The tip side of the jaw portion has a male shape and a female shape, and when machining is performed in a state where the male shape and the female shape are worn, insufficient compression or insufficient crimping occurs, resulting in wasted power consumption. [Means for solving the problem]

[0006] This invention has been made in view of the above circumstances, and aims to provide an electric power tool with a structure that is safe while increasing the reliability of processing work.

[0007] As one embodiment, the above problem is solved by the solution disclosed below.

[0008] The electric tool according to the present invention comprises a main body having an electric motor, a lead screw operated by the electric motor, a slide portion that moves by the lead screw, and a control unit, and a tool head having a first jaw portion and a second jaw portion connected to the main body and rotatably connected to each other, wherein the tool head is equipped with a spring that biases the tip side of the first jaw portion and the tip side of the second jaw portion toward each other, and is configured to process a workpiece with a first shaped portion on the tip side of the first jaw portion and a second shaped portion on the tip side of the second jaw portion, and has a current sensor that detects the current of the electric motor and a lower limit switch that is activated when the slide portion moves to its lower limit position. The control unit is configured such that, when the lower limit switch is activated, if the detected value of the current sensor exceeds the first current value but does not exceed the second current value, it determines that the workpiece is being processed normally and proceeds to the next step; and when the lower limit switch is activated, if the value exceeds the second current value, it determines that there is an abnormality and performs an abnormality processing.

[0009] With this configuration, when the control unit determines that the workpiece has been processed successfully, it can immediately proceed to the next step, thereby increasing the reliability of the processing work while reducing power consumption. Furthermore, when the control unit determines that there is a current abnormality, it can immediately perform abnormality processing, resulting in a highly safe structure.

[0010] Preferably, the control unit continues the operation of the lead screw when the detected value does not exceed the first current value when the lower limit switch is activated, and when the detected value falls below the second current value after the set time has elapsed following the first current value, it determines that the workpiece has been processed normally and proceeds to the next process. Furthermore, when the detected value exceeds the second current value after the set time has elapsed, it determines that there is an abnormality and performs the abnormality processing. With this configuration, the operation of the lead screw continues even if the male and female shapes at the tip of the jaws are worn. When the detected value falls below the second current value after the set time has elapsed following the first current value, the control unit determines that the workpiece has been processed normally and can immediately proceed to the next process, thus increasing the reliability of the processing work while taking into account the degree of wear of the male and female shapes at the tip of the jaws. Also, when the detected value exceeds the second current value after the set time has elapsed, it determines that there is an abnormality and can immediately perform the abnormality processing, resulting in a structure with superior safety.

[0011] Preferably, the main unit includes a display unit, a lower limit switch, an intermediate switch that is activated when the slide unit moves to an intermediate position, and an upper limit switch that is activated when the slide unit moves to an upper limit position. The control unit is configured to either move the slide unit to the intermediate position when it determines that the workpiece is being processed normally, or move the slide unit to the upper limit position and then move the slide unit to the intermediate position when it determines that the workpiece is being processed normally. Preferably, the control unit is configured to transmit an error signal to the display unit when it determines that there is an abnormality. With this configuration, if the workpiece is being processed normally, the next processing can be performed immediately in both automatic and manual modes. In addition, if there is a current abnormality, an error display is shown immediately, allowing for early detection of equipment malfunctions.

[0012] For example, the main body has a trigger switch and a control switch, and the control unit is configured to release the trigger switch before the lower limit switch is activated and, when the control switch is operated, to move the slide part to the intermediate position and stop it, and is configured to perform the stop control if neither the trigger switch nor the control switch is operated after a waiting time has elapsed since the intermediate switch was activated. With this configuration, stop control can be performed when the operator catches their finger on the tool head after the workpiece has started to be processed, thereby further enhancing safety during work. In addition, in automatic mode, stop control can be performed when the operator catches their finger on the tool head while the tip of the first jaw and the tip of the second jaw are open, thereby further enhancing safety during work.

[0013] As an example, the control unit is configured to perform mode switching control when the control switch is operated while the power is ON and the electric motor is stopped. This mode alternately switches between an automatic mode in which the workpiece is repeatedly processed with the tip of the first jaw and the tip of the second jaw open, and a manual mode in which the workpiece is processed once each with the tip of the first jaw and the tip of the second jaw closed.

[0014] As an example, the second jaw portion is configured to have an operating part that allows the operator to separate the first and second shaped portions from each other when the slide portion is in the intermediate position, thereby enabling the removal of the workpiece. With this configuration, when the slide portion is in the intermediate position, the operator can press the operating part on the second jaw portion, causing the tip of the second jaw portion to separate from the tip of the first jaw portion, making it easy to attach and position the workpiece and providing ease of use. As an example, the main body has a cover portion, and the operating part on the second jaw portion has a guide plate attached to the position where the operator presses it, shaped to correspond to the operator's finger. The cover portion can be made of a resin molded product or a metal press-formed product with an insulating treatment on the inner wall.

[0015] Preferably, the main body is configured to include a trigger switch that operates in conjunction with a trigger lever operated by the operator to drive the electric motor, and a control switch that operates at the operator's discretion to enable the operation of the trigger switch. Preferably, the intermediate switch is configured to operate when the slide portion moves to an intermediate position, and when the slide portion is in the intermediate position, the rear end of the first jaw portion and the first roller are separated, and the rear end of the second jaw portion and the second roller are separated. With this configuration, while it is a simple configuration combining a control switch and a trigger switch, safety is taken into consideration, and the operator can easily perform a series of necessary operations with one hand, resulting in a user-friendly configuration.

[0016] As an example, the lead screw is supported by a bearing and connected to the electric motor via a reduction gear. This configuration reduces rotational friction caused by the thrust load the lead screw receives when moving the slide. As an example, the slide is connected to a nut that converts the rotational motion of the lead screw into linear motion, or the slide is an integral part of the nut. A ball screw may be used as the lead screw. The bearing is a thrust bearing, and as an example, a thrust ball bearing or a thrust roller bearing may be used. Furthermore, by connecting the lead screw to the electric motor via a reduction gear, it is easy to generate high torque with a small electric motor. As an example, the reduction gear is a gearbox composed of multiple gears. The electric motor may be a geared motor with an integrated structure that combines the reduction gear. [Effects of the Invention]

[0017] According to the present invention, it is possible to realize an electric power tool with a structure that is highly safe while increasing the reliability of processing work. [Brief explanation of the drawing]

[0018] [Figure 1] Figure 1 is a circuit diagram showing an example of a schematic circuit configuration in the power tool of this embodiment. [Figure 2] Figure 2 is a current waveform graph showing an example of a schematic current waveform in the power tool of this embodiment. [Figure 3] Figure 3 is a schematic perspective view showing an example of the power tool of this embodiment. [Figure 4] Figure 4A is a rear view of the power tool shown in Figure 3, Figure 4B is a right side view of the power tool shown in Figure 3, Figure 4C is a front view of the power tool shown in Figure 3, and Figure 4D is a left side view of the power tool shown in Figure 3. [Figure 5] Figure 5A is a schematic structural view showing the state where the cover part of the power tool in Figure 3 is removed, and Figure 5B is a structural view showing the relationship between the trigger lever and the switch board in the power tool in Figure 3. [Figure 6] Figure 6A is a left side view of the tool head in the power tool shown in Figure 3, and Figure 6B is a front view of the tool head in the power tool shown in Figure 3. [Figure 7] Figure 7A is a schematic structural view showing the initial state in the usage mode of the power tool shown in Figure 3, Figure 7B is a schematic structural view showing the state where the workpiece is attached in the usage mode of the power tool shown in Figure 3, Figure 7C is a schematic structural view showing the state where the workpiece is compressed or crimped in the usage mode of the power tool shown in Figure 3, and Figure 7D is a schematic structural view showing the state where the workpiece is removed in the usage mode of the power tool shown in Figure 3. [Figure 8] Figure 8 is a view showing an example where the positions of the first jaw part and the second jaw part are interchanged in the schematic front view of the power tool shown in Figure 3. [Figure 9] Figure 9 is a view showing an example where the power tool shown in Figure 3 is placed horizontally.

Embodiments for Carrying out the Invention

[0019] Embodiments of the present invention will be described in detail below with reference to the drawings. The power tool 1 of this embodiment is a multi-functional power tool 1 with a replaceable tool head 3. Here, in order to make it easier to explain the positional relationship of each part of the power tool 1, the directions are indicated by X, Y, and Z arrows in the figure. Note that the power tool 1 operates normally in any direction.

[0020] The power tool 1 of this embodiment is configured to compress or crimp a workpiece 90 by driving an electric motor 7a using a battery pack 5 attached to an adapter 4 of the main body 2 as a power source. For example, the power tool 1 is used when crimping a crimp terminal to an electric wire at a work site, when compressing a crimp sleeve to join electric wires at a work site, or when compressing or crimping a workpiece 90 in a factory or workshop. In the diagrams illustrating the embodiment, components having the same function are denoted by the same reference numeral, and repeated explanations may be omitted.

[0021] Figures 3 and 4A to 4D are schematic diagrams showing an example of the power tool 1 according to this embodiment. The power tool 1 comprises a main body 2 having an electric motor 7a, a lead screw 8a, a slide part 9, a control unit 19, and a control switch 21, a tool head 3 having a first jaw part 11 and a second jaw part 12 connected to the main body 2 and rotatably connected to each other, and a battery pack 5, and is a cordless type tool that is held in the hand by a worker on site. The slide part 9 reciprocates along the axis P1 of the lead screw 8a. The slide part 9 moves forward to the upper limit position in the direction of the Z direction arrow in the figure and retracts to the lower limit position in the opposite direction of the Z direction arrow in the figure. When the slide part 9 is stopped at the intermediate position, the tip side of the tool head 3 is closed. In the initial state before the power is turned ON and the electric motor 7a starts operating, and in the initial state after the electric motor 7a has finished operating and the power is turned OFF, the slide part 9 stops at the intermediate position.

[0022] Figure 5A is a schematic structural diagram showing the state in which one side of the cover portion 2a of the main body 2 of the power tool 1 has been removed, and Figure 5B is a structural diagram showing the relationship between the trigger lever 27 and the switch board 20a of the power tool 1. The main body 2 has a horizontal mounting portion 15 formed in the cover portion 2a that allows it to be installed in a horizontal position. The horizontal mounting portion 15 has a flat portion 15a and a recessed portion 15b. The flat portion 15a has a flat surface formed around the recessed portion 15b, and the control switch 21 is housed in the recessed portion 15b, and the control switch 21 is lower than the flat portion 15a. The horizontal mounting portion 15 is in the right position when the trigger switch 22, which operates in conjunction with the operation of the trigger lever 27, is in the right position, and the horizontal mounting portion 15 is in the lower position when the trigger switch 22 is in the upper position. With this configuration, the stability when the main body 2 is placed horizontally is increased and accidental operation of the control switch 21 can be prevented.

[0023] For example, the control switch 21 is a push switch. The trigger lever 27 is pivotally supported on a second shaft member provided on the main body 2, and the trigger switch 22 operates in conjunction with the trigger lever 27. The trigger switch 22 is a microswitch. The switch board 20a has multiple microswitches mounted on it that can detect the position of the slide part 9. For example, the position of the slide part 9 is detected when a pin located on the slide part 9 makes contact with a microswitch.

[0024] The tool head 3 processes the workpiece 90 by applying the principle of leverage. The first jaw portion 11 has a first sliding surface 11d formed on the rear end side of the first jaw portion 11 on which the first roller 9a slides, and the first curved portion 11c from the protruding portion 11b of the first jaw portion 11 to the first sliding surface 11d is hollowed out so as to be separated from the first roller 9a. The second jaw portion 12 has a second sliding surface 12d formed on the rear end side of the second jaw portion 12 on which the second roller 9b slides, and the second curved portion 12c from the inner edge near where the first shaft member is located to the second sliding surface 12d is hollowed out so as to be separated from the second roller 9b. The first roller 9a and the second roller 9b constitute a pair of rollers, and this pair, the first roller 9a and the second roller 9b, are positioned symmetrically with respect to the axis P1 of the feed screw 8a. In other words, one of the rollers is positioned to slide on the rear end side of the first jaw portion 11, and another of the rollers is positioned to slide on the rear end side of the second jaw portion 12.

[0025] The lead screw 8a is supported by a bearing 8b and connected to the drive shaft 7b of the electric motor 7a via a reduction gear 6. The cover portion 2a of the main body 2 is shaped like a handle that can be gripped by the operator in a direction away from the tool head 3. An adapter 4 is provided on the lower end of the cover portion 2a, and the battery pack 5 is connected to the adapter 4.

[0026] Figures 6A and 6B show examples of tool heads 3 used for compressing or crimping a workpiece 90. The first jaw portion 11 and the second jaw portion 12 are each inserted through and supported by a first shaft member 17a, and are rotatably connected to each other by a connecting plate 17. The first shaped portion 11a at the tip of the first jaw portion 11 is a male shape with inwardly facing protrusions formed at predetermined intervals, and the second shaped portion 12a at the tip of the second jaw portion 12 is a female shape with inwardly facing recesses that correspond one-to-one with the protrusions. The first shaped portion 11a at the tip of the first jaw portion 11 and the second shaped portion 12a at the tip of the second jaw portion 12 approach each other to compress or crimp the workpiece 90, such as a compression terminal or crimping sleeve. The spring 18 is a torsion coil spring. The coil portion of the spring 18 is rotatably attached to a support portion 14a provided on the first jaw portion 11. The end of the spring 18 is in contact with the connecting plate 17. The restoring force of the spring 18 biases the first shaped portion 11a at the tip of the first jaw portion 11 and the second shaped portion 12a at the tip of the second jaw portion 12 toward each other. For example, the spring 18 is made of metal.

[0027] Figure 8 is a schematic front view showing an example of the power tool 1 according to this embodiment, and shows an example in which the positions of the first jaw portion 11 and the second jaw portion 12 are swapped. Figure 9 shows an example in which the main body 2 is placed on the workbench E1 with the main body 2 in a horizontal position. According to this embodiment, since the main body 2 is provided with a horizontal mounting portion 15, the main body 2 can be installed in a horizontal position as shown in Figure 9. When the main body 2 is placed on the workbench E1 with the main body 2 in a horizontal position, the flat portion 15a of the horizontal mounting portion 15 and the mounting surface E1a make surface contact, and a part of the battery pack 5 and the mounting surface E1a make surface contact, allowing the main body 2 to stand upright in the horizontal position. In the example shown in Figure 9, the trigger lever 27 is on the upper side, the first jaw portion 11 is on the upper side, and the second jaw portion 12 is on the lower side. The second shaped portion 12a at the tip side of the second jaw portion 12 has a female shape with an inward-facing recess, making it easier to set compression terminals and crimping sleeves as workpieces 90. As a result, the workpiece 90 can be easily processed.

[0028] As shown in Figure 8, the first jaw portion 11 and the second jaw portion 12 are shaped to be interchangeable and can be mounted in each other's positions. Furthermore, in any case where the positions of the first jaw portion 11 and the second jaw portion 12 are interchangeable, the configuration allows for compression or crimping of the workpiece 90. A support portion 14a can be attached to the mounting hole formed in the first jaw portion 11, and an operating portion 14b can be attached in place of the support portion 14a. Similarly, an operating portion 14b can be attached to the mounting hole formed in the second jaw portion 12, and the arrangement allows for the attachment of the support portion 14a in place of the support portion 14a.

[0029] With this configuration, the positions of the first jaw portion 11 and the second jaw portion 12 can be swapped to suit the operator's dominant hand and the layout of the work site. For example, the machine can be placed on its side and operated on, making it easy to align the workpiece 90 and allowing the workpiece 90 to be processed in the aligned position. Furthermore, the movement of the slide portion 9, which has a first roller 9a and a second roller 9b positioned symmetrically with respect to the axis P1, improves the balance between the external force applied to the first jaw portion 11 and the external force applied to the second jaw portion 12, allowing the workpiece 90 to be processed accurately and reliably while reducing power consumption.

[0030] As an example, the main unit 2 has a configuration that includes a battery pack 5 that supplies power to the electric motor 7a and an adapter 4 that detachably attaches the battery pack 5. This eliminates the need for a power cord, expands the working range, and allows for a compact and user-friendly structure. The cover portion 2a of the main unit 2 has a handle shape that can be gripped by the operator in a direction away from the tool head 3. The adapter 4 is provided below the handle shape of the cover portion 2a. As an example, the main unit 2 is configured to be able to stand on its own in a horizontal position and process the workpiece 90. This makes it easy to work stably with the main unit 2 placed horizontally.

[0031] The main body 2 has a lower limit switch 25 that is activated when the slide portion 9 moves to the lower limit position, an intermediate switch 24 that is activated when the slide portion 9 moves to the intermediate position, and an upper limit switch 23 that is activated when the slide portion 9 moves to the upper limit position. When the slide portion 9 is in the intermediate position, the main body 2 is biased by the spring 18 so that the tip side of the first jaw portion 11 and the tip side of the second jaw portion 12 are closed, and by moving the slide portion 9 backward, the tip side of the first jaw portion 11 and the tip side of the second jaw portion 12 are brought closer to each other to process the workpiece 90.

[0032] Figure 1 is a circuit diagram showing an example of the schematic circuit configuration of the power tool 1. The control unit 19 includes, as an example, a CPU 19a consisting of a single-chip microcontroller. The control unit 19 and the switch board 20a and display board 20b that constitute the peripheral circuits will be described below.

[0033] The secondary battery in the battery pack 5 is a lithium-ion battery, and as an example, the power supply voltage is 7 to 42 [V] and the battery capacity is 1 to 10 [Ah]. The voltage of the battery pack 5 is stepped down via the regulator 19c and supplied with power to the CPU 19a. The CPU 19a is configured to check and monitor the remaining charge of the battery pack 5. The control unit 19 has a current sensor 29 that detects the current of the electric motor 7a and a timer 28 that measures time. As an example, the CPU 19a is equipped with a sensor circuit that functions as the current sensor 29 and a timer circuit that functions as the timer 28. As an example, the CPU 19a sends a PWM signal to the driver 19b, supplies power to the electric motor 7a via a driving element such as a power MOSFET, and controls the driving of the electric motor 7a.

[0034] The control unit 19, the switch board 20a, and the display board 20b are signal-connected by wiring. The switch board 20a is equipped with a trigger switch 22 that is operated by the operation of the trigger lever 27, an upper limit switch 23 that is operated when the slide part 9 moves to the upper limit position, an intermediate switch 24 that is operated when the slide part 9 moves to the intermediate position, and a lower limit switch 25 that is operated when the slide part 9 moves to the lower limit position. The operating signals of each switch are input to the CPU 19a, which then drives and controls the electric motor 7a.

[0035] The main unit 2 has a display unit 26, which consists of LEDs 26a, 26b, and 26c. The control switch 21 operated by the operator, LED 26a which indicates that the power tool 1 is in automatic mode, LED 26b which indicates that the power tool 1 is in an abnormal state, and LED 26c which indicates that the power tool 1 is in manual mode are mounted on the display board 20b, and the control switch 21, LEDs 26a, 26b, and 26c are housed in the recessed portion 15b. When the operation signal of the control switch 21 is input to the CPU 19a, the CPU 19a determines the operation signal of the trigger switch 22 as an active signal and sets the conditions for driving and controlling the electric motor 7a. The control switch 21 is a push switch, and when the intermediate switch 24 is ON, the mode is switched each time the control switch 21 is pressed for a predetermined time, for example, for 3 seconds or more. Automatic mode is used for continuous operation, and the display control of the CPU 19a illuminates LED 26a, for example, displaying green. Manual mode is used for a single operation, and the display control of the CPU 19a illuminates LED 26c, for example, displaying green.

[0036] If the power tool 1 is in an abnormal state, an abnormality signal is input to the CPU 19a from an external sensor, and the display control of the CPU 19a causes the LED 26b to light up or blink, for example, displaying red. For example, when the current value of the battery pack 5 exceeds 20[A], the LED 26b blinks 10 times at a period of 5Hz. For example, when the board temperature of the control unit 19 reaches 80[°C], the LED 26b lights up for 3 seconds. For example, when the temperature of the battery pack 5 is 90[°C] or higher, the LED 26b blinks 3 times at a period of 1Hz. For example, when the voltage of the battery pack 5 is 7.8[V] or lower, the LED 26b blinks 10 times at a period of 5Hz. Note that the above values ​​are examples and are not limited to these values.

[0037] Table 1 shows the relationship between the operator's actions and the operation of the power tool 1 and the operation of the control switch 21, trigger switch 22, upper limit switch 23, intermediate switch 24, and lower limit switch 25. In Table 1, the first switch is the control switch 21, and the second switch is the trigger switch 22.

[0038] [Table 1]

[0039] As shown in Table 1, the simple configuration, combining a control switch 21 and a trigger switch 22 linked to the trigger lever 27, allows the operator to easily perform a series of necessary operations with one hand, making it user-friendly. Furthermore, the power turns on when the control switch 21 is activated, and turns off after a predetermined waiting time has elapsed from the moment the trigger lever 27 is released, which is rational. For example, the power turns off 60 seconds after the moment the trigger lever 27 is released.

[0040] Figures 7A to 7D are schematic diagrams illustrating the operation of power tool 1. The operation of power tool 1 will be explained below based on Figures 7A to 7D and Table 1.

[0041] Figure 7A shows the initial state where the slide part 9 is in the intermediate position. The intermediate position is the position where the first roller 9a is in contact with or close to the protrusion 11b. When the power is OFF, only the intermediate switch 24 is ON. When the slide part 9 is in the intermediate position, the restoring force of the spring 18 closes the tip side of the first jaw 11 and the tip side of the second jaw 12. The first crimping operation starts with the slide part 9 in the initial state shown in Figure 7A.

[0042] In step S1, when the operator presses and releases the control switch 21, the control switch 21 changes from OFF to ON and then to OFF, the power is turned ON by the control unit 19, and the operation of the trigger switch 22 is activated.

[0043] Following step S1, in step S2, the operator pushes the operating part 14b attached to the second jaw portion 12 toward the first jaw portion 11, causing the first shaped portion 11a to separate from the second shaped portion 12a, and the operator attaches the workpiece 90. Figure 7B shows the state in which the workpiece 90 is held between the first shaped portion 11a and the second shaped portion 12a.

[0044] Following step S2, in step S3, when the operator grips the trigger lever 27, the slide part 9 retracts and moves downward, causing the first roller 9a to slide on the first sliding surface 11d and the second roller 9b to slide on the second sliding surface 12d, so that the first shaped part 11a and the second shaped part 12a move closer to each other and press the workpiece 90 against it. When the slide part 9 reaches its lower limit position, the lower limit switch 25 is activated and the slide part 9 stops temporarily. Figure 7C shows the state after the workpiece 90 has been pressed against it.

[0045] Following step S3, in step S4, when the operator releases the trigger lever 27, the slide part 9 moves forward and upward, and the first roller 9a pushes the protruding part 11b, causing the first shaped part 11a and the second shaped part 12a to separate from each other. When the slide part 9 reaches the upper limit position, the upper limit switch 23 is activated and the slide part 9 stops temporarily.

[0046] Following step S4, in step S5, the operator removes the workpiece 90. Figure 7D shows the state after the workpiece 90 has been removed. After a predetermined time from the moment the operator releases the trigger lever 27, the power is turned off with the tip of the first jaw 11 and the tip of the second jaw 12 closed.

[0047] In automatic mode, the crimping operation is repeated from the state shown in Figure 7D. In manual mode, the crimping operation is performed one at a time from the state shown in Figure 7A.

[0048] According to this embodiment, the workpiece 90 can be easily positioned by gripping it with a constant force, and the workpiece 90 can be easily processed in the positioned state. Furthermore, in the initial state where the slide part 9 is in the intermediate position, the tip side of the tool head 3 is closed, so the burden on the operator is reduced compared to conventional products, resulting in an electric tool 1 with a superior safety structure.

[0049] Figure 2 is a current waveform graph showing an example of the current waveform U in the power tool 1. In addition to the explanation above, the operation of the power tool 1 will be explained below based on Figure 1.

[0050] In step S3, when the operator grips the trigger lever 27, the machining operation begins, the slide part 9 retracts, the machining operation progresses, and the lower limit switch 25 is activated. For example, the machining operation time is 1 to 3 seconds. When the lower limit switch 25 is activated, if the value detected by the current sensor 29 exceeds the first current value U1 but does not exceed the second current value U2, the control unit 19 determines that the machining of the workpiece 90 is normal and proceeds to the next step. If the value exceeds the second current value U2 when the lower limit switch 25 is activated, the control unit 19 determines that there is an abnormality and performs abnormality processing. For example, the first current value U1 is 8.5 to 9.5 [A] and the second current value U2 is 19.5 to 20.5 [A].

[0051] The control unit 19 continues the operation of the lead screw 8a if the value detected by the current sensor 29 does not exceed the first current value U1 when the lower limit switch 25 is activated. If the detected value falls below the second current value U2 after the set time T1 has elapsed since the first current value U1 was exceeded, the control unit 19 determines that the machining of the workpiece 90 is normal and proceeds to the next process. If the detected value exceeds the second current value U2 after the set time T1 has elapsed, the control unit 19 determines that there is an abnormality and performs abnormality processing. For example, the set time T1 is 5 to 15 [ms].

[0052] The control unit 19 then controls the slide unit 9 to move to the intermediate position when it determines that the processing of the workpiece 90 is normal. Alternatively, the control unit 19 controls the slide unit 9 to move to the upper limit position and then to the intermediate position when it determines that the processing of the workpiece 90 is normal. Furthermore, the control unit 19 transmits an error signal to the display unit 26 and performs the stop control when it determines that there is an abnormality.

[0053] According to this embodiment, the power tool 1 has a structure that is highly safe while increasing the reliability of the machining work. The present invention is not limited to the embodiments described above, and various modifications are possible without departing from the present invention. [Explanation of symbols]

[0054] 1 Power tools 2 Main unit, 2a Cover part 3 Tool heads 4 adapters 5 Battery Packs 6 Reducer 7a Electric motor, 7b Drive shaft 8a Lead screw, 8b Bearing 9. Slide section, 9a. Roller (first roller), 9b. Roller (second roller) 11 First jaw portion, 11a First shaped portion, 11b Protruding portion, 11c First curved portion, 11d First sliding surface 12 Second jaw portion, 12a Second shaped portion, 12c Second curved portion, 12d Second sliding surface 14a Support part, 14b Operation part 15 Horizontal part, 15a flat part, 15b recessed part 17 Connection plate, 17a 1st shaft member 18 springs 19 Control unit, 19a CPU (microcontroller), 19b Driver, 19c Regulator 20a Switch board, 20b Display board 21 Control switch 22 Trigger Switches 23 Upper limit switch 24 In-line switch 25 Lower limit switch 26 Display, 26a, 26b, 26c LED 27 Trigger lever, 27a Second axis member 28 timers 29 Current Sensor 90 Workpiece P1 axis U: Current waveform, U1: First current value

Claims

1. The device comprises a main body having an electric motor, a lead screw operated by the electric motor, a slide portion that moves by the lead screw, and a control unit, and a tool head having a first jaw portion and a second jaw portion connected to the main body and rotatably connected to each other, wherein the tool head is equipped with a spring that biases the tip side of the first jaw portion and the tip side of the second jaw portion toward each other, and the workpiece is processed by the first shaped portion on the tip side of the first jaw portion and the second shaped portion on the tip side of the second jaw portion, and has a current sensor for detecting the current of the electric motor and a lower limit switch that is activated when the slide portion moves to its lower limit position. The control unit is configured such that, when the lower limit switch is activated, if the detected value of the current sensor exceeds the first current value but does not exceed the second current value, it determines that the workpiece is being processed normally and proceeds to the next step. If, when the lower limit switch is activated, the value exceeds the second current value, it determines that there is an abnormality and performs an abnormality processing. Power tools characterized by [features].

2. The control unit is configured to continue operating the lead screw if the detected value does not exceed the first current value when the lower limit switch is activated, and if the detected value falls below the second current value after the set time has elapsed and the current value exceeds the first current value, it determines that the workpiece is being machined normally and proceeds to the next step, and if the detected value exceeds the second current value after the set time has elapsed, it determines that there is an abnormality and performs the abnormality processing. The power tool according to claim 1, characterized by the following:

3. The main body includes a display unit, a lower limit switch, an intermediate switch that is operated by moving the slide unit to an intermediate position, and an upper limit switch that is operated by moving the slide unit to an upper limit position. The control unit is configured to either move the slide portion to the intermediate position when it determines that the workpiece is being processed normally, or to move the slide portion to the upper limit position and then to the intermediate position when it determines that the workpiece is being processed normally. The control unit is configured to transmit an error signal to the display unit when it determines that there is an abnormality. The power tool according to claim 1, characterized by the following:

4. The main body includes a display unit, a lower limit switch, an intermediate switch that is operated by moving the slide unit to an intermediate position, and an upper limit switch that is operated by moving the slide unit to an upper limit position. The control unit is configured to either move the slide portion to the intermediate position when it determines that the workpiece is being processed normally, or to move the slide portion to the upper limit position and then to the intermediate position when it determines that the workpiece is being processed normally. The control unit is configured to transmit an error signal to the display unit when it determines that there is an abnormality. The power tool according to claim 2, characterized by the following:

5. The main body has a trigger switch and a control switch, The control unit is configured to perform stop control, which moves the slide portion to the intermediate position and stops it, when the trigger switch is released and the control switch is operated before the lower limit switch is activated, and when neither the trigger switch nor the control switch is operated after a waiting period has elapsed since the intermediate switch was activated. The power tool according to claim 3, characterized by the following:

6. The main body has a trigger switch and a control switch, The control unit is configured to perform stop control, which moves the slide portion to the intermediate position and stops it, when the trigger switch is released and the control switch is operated before the lower limit switch is activated, and when neither the trigger switch nor the control switch is operated after a waiting period has elapsed since the intermediate switch was activated. The power tool according to claim 4, characterized by the following:

7. The main body includes a battery pack that supplies power to the electric motor and an adapter that allows the battery pack to be attached detachably. The sliding portion has a first roller positioned to slide on the rear end side of the first jaw portion and a second roller positioned to slide on the rear end side of the second jaw portion, and is configured to compress or press the workpiece by moving the sliding portion to the lower limit position. A power tool according to any one of claims 1 to 6, characterized by the following:

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