trigger switch

Abstract

The present application provides a trigger switch capable of detecting the amount of pressing of a trigger subjected to a pressing operation in a non-contact manner and excluding the influence of an external environmental magnetic field. The trigger switch (TS) has a first conductive plate (40) (movable electrode) that moves with the movement of a trigger (1) due to a pressing operation, and a second fixed electrode (51) (fixed electrode) that is disposed apart by a gap in the vicinity of the movement range of the first conductive plate (40) and forms a capacitor with the first conductive plate (40). The electrostatic capacity of the capacitor formed by the first conductive plate (40) and the second fixed electrode (51) of the trigger switch (TS) changes with the movement of the first conductive plate (40).

Description

Technical Field

[0001] The present invention relates to a trigger switch that moves in response to the pressing operation of a trigger. Background Technology

[0002] Trigger switches that control the operation of power tools by accepting pressing operations are in use. For example, Patent Document 1 discloses a trigger switch that uses a magnetic sensor to detect the amount of pressure applied to the trigger. The trigger switch described in Patent Document 1, by using a magnetic sensor, can detect the amount of pressure applied to the trigger in a non-contact manner, thereby extending its lifespan.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: International Publication No. 2020 / 231974 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] However, when the trigger switch of the magnetic sensor described in Patent Document 1 is assembled in a power tool for operation, malfunctions may occur due to changes in the magnetic field of the external environment. For example, the trigger switch of the power tool may be used near sources of magnetic field, such as cranes that use strong electromagnets to grip iron filings or motors inside the device itself, so malfunctions may occur due to magnetic field generated from such sources.

[0008] The present invention is proposed in view of the above-mentioned problems, and aims to provide a trigger switch that can detect the amount of trigger press in a non-contact manner and is not affected by the magnetic field of the external environment.

[0009] Technical solutions for solving technical problems

[0010] To solve the above problems, the trigger switch described in this application is a trigger switch having a trigger that moves in response to a pressing operation. The trigger switch is characterized by having: a movable electrode that moves with the movement of the trigger caused by the pressing operation, and a fixed electrode disposed near the movement range of the movable electrode and forming a capacitance with the movable electrode, wherein the capacitance formed by the movable electrode and the fixed electrode changes with the movement of the movable electrode.

[0011] Furthermore, based on the trigger switch, the fixed electrode is characterized in that the electrode area forming the capacitor changes according to the position of the movable electrode within the movement range.

[0012] Furthermore, based on the trigger switch, the fixed electrode is characterized in that the electrode area forming the capacitor gradually increases along the moving direction based on the pressing operation.

[0013] Furthermore, based on the trigger switch, it is characterized by having: an operating component that receives an operation and is actuated, a secondary movable electrode that moves with the operation of the operating component, and a secondary fixed electrode that forms a capacitance with the secondary movable electrode when the secondary movable electrode is located nearby. By moving with the operation of the operating component, the secondary movable electrode moves within a range between a position where a capacitance is formed with the secondary fixed electrode and a position where no capacitance is formed.

[0014] Furthermore, based on the trigger switch, it is characterized in that it can be assembled in an electric device having a drive unit driven by an electrical signal, and also has an output unit that outputs an electrical signal to drive the drive unit, the output unit outputting an electrical signal to drive the drive unit with an output corresponding to the capacitance of the capacitor formed by the movable electrode and the fixed electrode.

[0015] The trigger switch described in this application changes its capacitance according to the pressing operation.

[0016] The effects of the invention

[0017] The trigger switch of the present invention comprises: a movable electrode that moves with the pressing operation of a trigger, and a fixed electrode that forms a capacitor with the movable electrode. The capacitance of the capacitor formed by the movable electrode and the fixed electrode changes with the movement of the movable electrode. Therefore, the trigger switch of the present invention can detect the pressing amount of the trigger by capacitance, thus having the advantages of eliminating the influence of external environmental magnetic fields. Attached Figure Description

[0018] Figure 1 This is a schematic perspective view showing an example of the appearance of the trigger switch described in this application.

[0019] Figure 2 This is an exploded perspective view showing an example of the trigger switch described in this application.

[0020] Figure 3 This is a schematic side view illustrating an example of the trigger switch described in this application.

[0021] Figure 4A This is a schematic top view illustrating an example of the appearance of the switching lever of the trigger switch described in this application.

[0022] Figure 4B This is a schematic front view illustrating an example of the appearance of the switching lever of the trigger switch described in this application.

[0023] Figure 5 This is a schematic rear view showing an example of the appearance of the fixed component of the trigger switch described in this application.

[0024] Figure 6 This is a schematic front view showing an example of the appearance of the movable and fixed parts of the trigger switch described in this application.

[0025] Figure 7 This is a schematic side view illustrating an example of the trigger switch described in this application.

[0026] Figure 8 This is a schematic side view illustrating an example of the trigger switch described in this application.

[0027] Figure 9 This is a schematic side view illustrating an example of the trigger switch described in this application.

[0028] Figure 10 This is a block diagram schematically representing an example of a first capacitor formed by the trigger switch described in this application.

[0029] Figure 11A This is a schematic diagram showing an example of the appearance of the switching lever and fixing components of the trigger switch described in this application.

[0030] Figure 11B This is a schematic diagram showing an example of the appearance of the switching lever and fixing components of the trigger switch described in this application.

[0031] Figure 12A This is a schematic diagram showing an example of the appearance of the switching lever and fixing components of the trigger switch described in this application.

[0032] Figure 12B This is a schematic diagram showing an example of the appearance of the switching lever and fixing components of the trigger switch described in this application.

[0033] Figure 13 This is a block diagram conceptually representing an example of a second capacitor formed by the trigger switch described in this application.

[0034] Figure 14 This is a schematic block diagram illustrating an example of a control structure of an electric device equipped with the trigger switch described in this application.

[0035] Figure 15 This is a graph that conceptually represents an example of the relationship between the amount of pressure applied to the trigger of the trigger switch described in this application and its capacitance and output.

[0036] Figure 16 This is a schematic rear view showing an example of the appearance of the fixed component of the trigger switch described in this application. Detailed Implementation

[0037] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0038] <Application Examples>

[0039] The trigger switch described in this application is used in various electric devices, primarily electric tools such as electric drills, electric saws, electric actuators, electric wrenches, and electric grinders, which have drive units such as motors. In the following embodiments, the trigger switch TS is illustrated and explained with reference to the accompanying drawings.

[0040] <Implementation Method>

[0041] Figure 1 This is a schematic perspective view showing an example of the appearance of the trigger switch TS described in this application. Figure 1 This indicates that it can be used in various electric devices such as power tools (ET). Figure 14 The appearance of the trigger switch TS assembled in the device ET. The trigger switch TS is a switch operated by the user of the electric device ET. When the user presses the trigger 1 of the trigger switch TS, the drive unit M (see reference) such as the electric motor built into the electric device ET is activated. Figure 14 The trigger switch TS is driven by a generally rectangular housing 2 assembled in the electric actuator ET, and a user-pressable trigger 1. Additionally, the trigger switch TS has a switching lever 3 (operating component) that accepts the operation of switching the driving direction of the drive unit M, such as the rotation direction of the electric actuator, in either the forward or reverse direction. It should be noted that, in the following description, the orientation of the trigger switch TS will be... Figure 1 The description uses the right front side as the front, the left depth side as the rear, the left front side where the trigger 1 is installed as the front, and the right front side that becomes the side of the housing 2 as the rear. However, this is a direction for ease of explanation and is not intended to limit the direction in which the trigger switch TS is used. The front half of the front side and the rear half of the rear side are combined to form the housing 2, and various components are assembled inside the housing 2.

[0042] The internal structure of the trigger switch TS will be explained. Figure 2 This is an exploded perspective view showing an example of the trigger switch TS described in this application. Figure 3 This is a schematic side view illustrating an example of the trigger switch TS described in this application. Figure 2 and Figure 3To make the internal structure easier to see, the front half of the front side of the housing 2, which faces the drawing and is the near-front side, is omitted. In addition to a part of the trigger 1 and a part of the switching lever 3, the housing 2 also houses various components such as movable parts 4, fixed parts 5, and locking parts 6. Figure 2 and Figure 3 The perspective view shows a portion of the fixed component 5.

[0043] The trigger switch TS has a trigger 1 with a shaft portion 10 extending towards the housing 2. The shaft portion 10 is formed into an elongated cylindrical shape, penetrating a through hole 20 formed in the left wall of the housing 2 and inserted into the interior of the housing 2. A first force-applying member 11, such as a compression coil spring serving as a return spring, is wound around the shaft portion 10. The left end of the first force-applying member 11 abuts against the trigger 1, and the right end abuts against the wall of the housing 2, applying force to the left side of the trigger 1. The first force-applying member 11 is covered by a flexible cover member 12. When the trigger 1 receives a pressing operation, the trigger 1 and the shaft portion 10 move to the right side, which is the pressing direction. When the pressing operation is released, the first force-applying member 11 applies force to the left side, which is the opposite direction to the pressing direction of the trigger 1, so the trigger 1 and the shaft portion 10 move to the left side.

[0044] A movable member 4 is mounted on the right end of the shaft portion 10, which houses the trigger 1 within the housing 2, in the pressing direction. The movable member 4 is generally rectangular in shape and is mounted on the shaft portion 10 via its left side, so it moves in the pressing direction as the trigger 1 moves after being pressed. A first conductive plate 40 (movable electrode) of a generally rectangular shape is mounted on the front surface of the movable member 4. The first conductive plate 40 is a conductor formed using a conductive metal plate. The first conductive plate 40 is formed in a longitudinally elongated rectangular shape when viewed from the front, and isolation members 41, which act as spacers, are mounted on the upper and lower parts of the front surface to isolate the first conductive plate 40 from the fixed member 5. The isolation members 41 prevent the first conductive plate 40 from contacting the fixed member 5 by abutting against it. During the movement of the movable member 4, the isolation members 41 slide on the fixed member 5 in the abutting state. Because the isolation members 41 do not affect the capacitance, various materials such as insulators and conductors can be used to form it.

[0045] Figure 4A This is a schematic top view showing an example of the appearance of the switching lever 3 of the trigger switch TS described in this application. Figure 4B This is a schematic front view illustrating an example of the appearance of the switching lever 3 of the trigger switch TS described in this application. (Utilizing...) Figure 2 , Figure 3 , Figure 4A and Figure 4BThe switching lever 3 will be described below. The switching lever 3 comprises a lever portion 30 for receiving the user's swing operation, a swing shaft portion 31 serving as the swing axis, and an action portion 32 that actuates through the swing operation. The switching lever 3 is supported by the swing shaft portion 31 in a support hole 21 on the upper surface of the housing 2, allowing it to swing freely. The lever portion 30 is mounted extending to the left from the upper end of the swing shaft portion 31, located above the housing 2. The action portion 32, housed within the housing 2, is mounted at the lower end of the swing shaft portion 31 and extends to the right. The action portion 32, viewed from above, is approximately pentagonal with rounded corners, and a semi-circular engagement protrusion 320 protrudes from the apex of its right-side front portion, engaging with the engagement member 6. A generally rectangular second conductive plate 321 (secondary movable electrode) is mounted on the lower surface of the action portion 32. The second conductive plate 321 is a conductor formed using a conductive metal sheet.

[0046] like Figure 2 and Figure 3 As an example, on the right side of the switching lever 3, a locking member 6 is provided, which serves as a push rod to press the switching lever 3 to the left. The left end of the locking member 6, opposite the switching lever 3, is M-shaped when viewed from above. In addition, a second force-applying member 60, such as a compression coil spring, is installed on the right side of the locking member 6 to apply force to the locking member 6 as a push rod spring.

[0047] The user operates the swing switch lever 3, causing it to swing. The swinging switch lever 3 presses against the engaging member 6, which is subjected to force by the second force-applying member 60. Due to the pressure of the engaging member 6, the engaging protrusion 320 of the switch lever 3 engages with the M-shaped recess or side portion on the left end of the engaging member 6, thus keeping the switch lever 3 in the swinging position.

[0048] Figure 5 This is a schematic rear view showing an example of the appearance of the fixed component 5 of the trigger switch TS described in this application. Figure 6 This is a schematic front view showing an example of the appearance of the movable part 4 and the fixed part 5 of the trigger switch TS described in this application. Figure 6 Perspective view of the fixed component 5 is used to clearly show its positional relationship with the movable component 4. Utilizing... Figure 2 , Figure 3 , Figure 5 and Figure 6 The fixing member 5 will be described below. The fixing member 5 is a substrate formed into a generally rectangular shape. As a substrate, the fixing member 5 has various circuits, components, wiring, and other main structural components of electronic circuits disposed or connected on its front surface. Specifically, a control unit 55 (see below) is disposed or connected thereto. Figure 10 etc.), First Detection Department 56 (refer to) Figure 10 etc.), Second Inspection Department 57 (refer to) Figure 13etc.), output section 58 (refer to) Figure 14 The main structural components of the electronic circuit (etc.). The fixing component 5 has a first fixing electrode 50 and a second fixing electrode 51 (fixed electrode), as well as a third fixing electrode 52 and a fourth fixing electrode 53 (sub-fixed electrode) disposed on its rear surface, and has two guide shapes (planned shapes) 54 formed thereon.

[0049] The first fixed electrode 50 and the second fixed electrode 51 are arranged in two layers near the center of the fixed member 5. The first fixed electrode 50, located on the upper side, is a rectangular conductive metal plate extending in the left-right direction of the movable member 4, which moves with the movement of the trigger 1. The second fixed electrode 51, located on the lower side, is a right-angled triangular conductive metal plate extending in the left-right direction of the movable member 4. The second fixed electrode 51 is a triangular shape whose length gradually increases in the right-right direction and vertical direction of the movement based on the pressing operation. The first fixed electrode 50 and the second fixed electrode 51 form a first capacitor with the first conductive plate 40 of the nearby movable member 4. The electrode area of ​​the second fixed electrode 51, which is triangular in shape, gradually increases along the movement direction of the first conductive plate 40 based on the pressing operation.

[0050] Two guide shapes 54 are formed above the first fixed electrode 50 and below the second fixed electrode 51. The two guide shapes 54 extend in the left-right direction, which is the direction of movement of the movable member 4, and are formed, for example, as grooves into which the isolation member 41 is fitted. The upper and lower isolation members 41 of the movable member 4 contact the guide shapes 54 to guide the left-right movement of the movable member 4.

[0051] The third fixed electrode 52 and the fourth fixed electrode 53 are arranged side by side near the upper end of the fixing member 5. The square-shaped third fixed electrode 52 is arranged on the right side, and the square-shaped fourth fixed electrode 53 is arranged on the left side. When the second conductive plate 321 of the switching lever 3 is located nearby, the third fixed electrode 52 and the fourth fixed electrode 53 form a second capacitor with the second conductive plate 321.

[0052] Next, the operation of the trigger switch TS described in this application will be explained. Figures 7 to 9 This is a schematic side view illustrating an example of the trigger switch TS described in this application. Figures 7 to 9 The front half of the front side of the basket 2 is omitted, and the perspective shows a part of the fixing part 5.

[0053] Figure 7This indicates that the trigger switch TS is not receiving a pressing operation on trigger 1. In this state, trigger 1 is stressed by the first force-applying component 11 and is located at the left end of its movement range. The movable component 4, mounted on the shaft 10 of trigger 1, is also similarly located at the left end of its movement range. When the movable component 4 is located at the left end of its movement range... Figure 7 In the state shown, the first fixed electrode 50 and the second fixed electrode 51 are isolated from the first conductive plate 40 mounted on the movable part 4. Therefore, the first conductive plate 40 and the first fixed electrode 50 and the second fixed electrode 51 will not form a capacitor with sufficient electrostatic capacitance.

[0054] Figure 8 Indicates that trigger 1 starts from Figure 7 The state shown is the state after a press operation. The trigger 1, having received the press operation, moves to the right in the pressing direction. As the trigger 1 moves, the movable part 4 moves to the right. Figure 8 In the state shown, since the first fixed electrode 50 and the second fixed electrode 51 are arranged near the first conductive plate 40 on which the movable part 4 is mounted, the first conductive plate 40, the first fixed electrode 50 and the second fixed electrode 51 form a first capacitor.

[0055] Figure 9 Indicates that trigger 1 starts from Figure 8 The state shown is further shown after a press operation. Trigger 1, having received a press operation, [receives the following]: Figure 8 The state shown moves further to the right. As the trigger 1, which has received a press operation, moves, the movable part 4 from... Figure 8 The state shown has moved further to the right. Figure 9 In the shown state, because the first fixed electrode 50 and the second fixed electrode 51 are arranged near the first conductive plate 40 on which the movable part 4 is mounted, a first capacitor is formed by the first conductive plate 40, the first fixed electrode 50, and the second fixed electrode 51. Figure 8 Compared to the state shown, in Figure 9 In the state shown, the electrode area of ​​the second fixed electrode 51 that forms the first capacitor with the first conductive plate 40 increases, so the electrostatic capacitance of the first capacitor formed by the first conductive plate 40 and the second fixed electrode 51 increases.

[0056] When the user releases the press operation of trigger 1, trigger 1 is pushed to the left in the opposite direction to the pressing direction due to the force of the first force-applying component 11, and returns to its original state. Figure 7 The example states.

[0057] Figure 10This is a block diagram conceptually representing an example of a first capacitor formed by the trigger switch TS described in this application. A control unit 55 configured using a microcomputer and a first detection unit 56 for detecting capacitance are disposed or connected to the front surface of the substrate used as a fixing member 5. A first fixed electrode 50 is connected to ground. A second fixed electrode 51 is connected to the first detection unit 56 for detecting capacitance. The first detection unit 56 is connected to the second fixed electrode 51 and ground, detects the capacitance of the first capacitor, and outputs an electrical signal representing the detected capacitance to the control unit 55. Because the first fixed electrode 50 is disposed near the first conductive plate 40, the first fixed electrode 50 and the first conductive plate 40 form a capacitor. Because the second fixed electrode 51 is disposed near the first conductive plate 40, the second fixed electrode 51 and the first conductive plate 40 form a capacitor. The capacitance of the capacitor formed by the first fixed electrode 50 and the first conductive plate 40 is C1, and the capacitance of the capacitor formed by the second fixed electrode 51 and the first conductive plate 40 is C2. The first capacitor that becomes the composite capacitor can be regarded as a component consisting of a capacitor with capacitance C1 and a capacitor with capacitance C2 connected in series. Therefore, the capacitance C12 of the first capacitor can be calculated by the following equation 1.

[0058] C12=(C1×C2) / (C1+C2)…Equation 1

[0059] Wherein, C12: the capacitance of the first capacitor.

[0060] C1: Capacitance of the capacitor formed by the first fixed electrode 50 and the first conductive plate 40; C2: Capacitance of the capacitor formed by the second fixed electrode 51 and the first conductive plate 40.

[0061] Because the electrode area of ​​the second fixed electrode 51, which forms a capacitor with the first conductive plate 40, gradually increases along the direction of movement based on the pressing operation, the value of the capacitance C2 gradually increases as the movable part 4 moves. When the capacitance C2 increases, the capacitance C12 of the first capacitor also increases, as shown in Equation 1.

[0062] Figure 11A and Figure 11B ,as well as Figure 12A and Figure 12B This is a schematic diagram showing an example of the appearance of the switching lever 3 and the fixing component 5 of the trigger switch TS described in this application. Figure 11A It is a summary 3D diagram. Figure 11B This is a left-side summary view. Figure 11A and Figure 11B This indicates that the switching lever 3 accepts a right-turn (clockwise) swing operation when viewed from above, and the second conductive plate 321, mounted on the lower surface of the actuating part 32 of the switching lever 3, is located near the fixing member 5. Figure 11A and Figure 11B In the illustrated state, the second conductive plate 321 forms a second capacitor with the third fixed electrode 52 and the fourth fixed electrode 53.

[0063] Figure 12A It is a 3D exterior view. Figure 12B This is a left-side summary view. Figure 12A and Figure 12B This indicates that the switching lever 3 accepts a leftward (counter-clockwise) swing operation viewed from above, and that the second conductive plate 321 is isolated from the vicinity of the fixed component 5. Figure 12A and Figure 12B In the illustrated state, a second capacitor is not formed by the second conductive plate 321, the third fixed electrode 52, and the fourth fixed electrode 53. By moving the switching lever 3, the second conductive plate 321 will form a capacitor with the third fixed electrode 52 and the fourth fixed electrode 53. Figure 11A and Figure 11B The locations shown, and those without capacitors Figure 12A and Figure 12B The indicated positions are used as the range of movement.

[0064] Figure 13 This is a block diagram conceptually representing an example of a second capacitor formed by the trigger switch TS described in this application. A control unit 55 and a second capacitance detection unit 57 are disposed or connected to the front surface of the substrate used as a fixing member 5. A third fixing electrode 52 is connected to ground. A fourth fixing electrode 53 is connected to the second capacitance detection unit 57. The second detection unit 57 is connected to the fourth fixing electrode 53 and ground, detects the capacitance of the second capacitor, and outputs an electrical signal representing the detected capacitance to the control unit 55. The second conductive plate 321, indicated by solid lines, is shown as follows... Figure 11A and Figure 11B The example illustrates the state near the third fixed electrode 52 and the fourth fixed electrode 53. With the second conductive plate 321 located near the third fixed electrode 52 and the fourth fixed electrode 53, the second conductive plate 321 and the third fixed electrode 52 form a capacitor, and the second conductive plate 321 and the fourth fixed electrode 53 form a capacitor. The capacitance of the capacitor formed by the third fixed electrode 52 and the second conductive plate 321 is C3, and the capacitance of the capacitor formed by the fourth fixed electrode 53 and the second conductive plate 321 is C4. The second capacitor, which becomes the combined capacitor, can be considered as a component consisting of a capacitor with capacitance C3 and a capacitor with capacitance C4 connected in series. Therefore, the capacitance C34 of the second capacitor can be calculated using Equation 2 below.

[0065] C34=(C3×C4) / (C3+C4)…Equation 2

[0066] Wherein, C34: the capacitance of the second capacitor.

[0067] C3: Capacitance of the capacitor formed by the third fixed electrode 52 and the second conductive plate 321; C4: Capacitance of the capacitor formed by the fourth fixed electrode 53 and the second conductive plate 321.

[0068] exist Figure 13 In the diagram, the second conductive plate 321, represented by the dashed line, represents... Figure 12A and Figure 12B The example illustrates the state of isolation from the third fixed electrode 52 and the fourth fixed electrode 53. In this isolated state, the second conductive plate 321 does not form an effective capacitance; therefore, the capacitance detected by the second detection unit 57 is 0 or close to 0.

[0069] Next, a structural example of an electric device ET equipped with the trigger switch TS described in this application will be described. Figure 14 This is a schematic block diagram illustrating a portion of the control structure of an electric device ET equipped with the trigger switch TS described in this application. The electric device ET, such as a power tool, is formed by assembling the trigger switch TS within a main unit MU. The main unit MU includes a drive unit M, such as a motor. In addition to the control unit 55, the first detection unit 56, and the second detection unit 57, the trigger switch TS also includes an output unit 58 that outputs an electrical signal to the drive unit M based on the control of the control unit 55.

[0070] The control unit 55 of the trigger switch TS receives the capacitance of the first capacitor detected by the first detection unit 56 and the capacitance of the second capacitor detected by the second detection unit 57. Based on the capacitance of the first capacitor detected by the first detection unit 56, the control unit 55 determines the output of the drive unit M, such as the motor rotation speed. For example, if the trigger 1 is pressed, forming the first capacitor, and the capacitance increases, the control unit 55 determines the output corresponding to the capacitance of the first capacitor based on the pressing operation. Based on the capacitance of the second capacitor detected by the second detection unit 57, the control unit 55 determines the driving method of the drive unit M, such as the motor rotation direction. For example, if the switching lever 3 is turned right, forming the second capacitor, and the capacitance detected by the second detection unit 57 is above a preset threshold, the motor rotation direction is determined to be forward. If the switching lever 3 is turned left and the capacitance detected by the second detection unit 57 is below the threshold, the motor rotation direction is determined to be reverse.

[0071] The control unit 55 of the trigger switch TS outputs an electrical signal from the output unit 58 to the main device MU to drive the drive unit M, based on the driving method determined by the detection result of the second detection unit 57 and the output determined by the detection result of the first detection unit 56.

[0072] The main unit MU drives the drive unit M based on the electrical signal input from the trigger switch TS.

[0073] Figure 15 This is a graph that conceptually represents an example of the relationship between the pressed amount of trigger 1 of the trigger switch TS described in this application and its capacitance and output. Figure 15 The diagram shows the relationship between the horizontal axis representing the stroke of the trigger 1 and the vertical axis representing the capacitance of the first capacitor and the output value from the output unit 58 to the drive unit M. For example... Figure 7 For example, when the trigger 1 has no pressing operation and its travel is 0, the first conductive plate 40, the first fixed electrode 50, and the second fixed electrode 51 do not form a capacitance. Therefore, the capacitance is 0, and the output value from the output unit 58 is also 0. Figure 8 For example, when the trigger 1 is pressed to S1, the first conductive plate 40, the first fixed electrode 50, and the second fixed electrode 51 form a capacitor. When the trigger 1 is pressed further from S1, the capacitance of the capacitor formed by the second fixed electrode 51 and the first conductive plate 40 increases according to the stroke value, so the capacitance of the first capacitor, which is the combined capacitance, increases. Figure 15 The example shown illustrates an instance where the output value increases with a constant slope relative to the amount of pressure applied. For example... Figure 9 For example, when trigger 1 is pressed to S2, control unit 55 adjusts the output value to drive at a constant speed relative to subsequent pressing operations (S2 and later). It should be noted that the capacitance of the first capacitor does not increase at a constant angle relative to the pressing amount; furthermore, it tends to increase for pressing operations (S2 and later), but... Figure 15 For ease of understanding, this is conceptually represented as the trend of the control unit 55 controlling the output value.

[0074] As described above, in the trigger switch TS of this application, the first conductive plate 40 moves with the pressing operation of the trigger 1, forming a capacitance with the first fixed electrode 50 and the second fixed electrode 51 mounted on the fixed component 5. For example, by forming the second fixed electrode 51 into a roughly triangular shape or similar shape, the electrode area forming the capacitance changes depending on the position of the first conductive plate 40 within its movement range, and the capacitance changes according to the pressing amount of the trigger 1. Therefore, the trigger switch TS of this application can detect the pressing amount of the trigger 1 by means of capacitance. The trigger switch TS of this application detects the pressing amount of the trigger 1 by means of capacitance, thereby enabling non-contact detection of the pressing amount, thus having the advantages of suppressing deterioration caused by friction and extending the service life. Furthermore, the trigger switch TS of this application, unlike non-contact detection using magnetic sensors, has the advantages of eliminating the influence of external environmental magnetic fields.

[0075] Furthermore, the trigger switch TS described in this application forms a capacitor by a second conductive plate 321 mounted on the switching rod 3 and a third fixed electrode 52 and a fourth fixed electrode 53 mounted on the fixing component 5. As a result, it has the good effect of being able to combine other controls such as switching of driving methods.

[0076] This invention is not limited to the embodiments described above, and can be implemented in various other ways. Therefore, the above embodiments are merely illustrative in all respects and are not limiting descriptions. The technical scope of this invention is defined by the scope of the technical solution, and is not limited to this specification. Furthermore, modifications and variations within the equivalent scope of the technical solution are included within the scope of this invention.

[0077] For example, in the described embodiment, the second fixed electrode 51 is shown as a triangular shape in which the electrode area forming the capacitor gradually increases along the movement direction based on the pressing operation. However, the present invention is not limited to this, and various shapes can be formed as long as the electrode area changes. For example, the second fixed electrode 51 of the trigger switch TS of the present invention can be a triangular shape in which the electrode area gradually decreases through the pressing operation, or it can be a trapezoidal shape in which the electrode area initially gradually increases and then becomes constant in the middle. Furthermore, the second fixed electrode 51 of the trigger switch TS of the present invention can be modified into various configurations and shapes. Figure 16 This is a schematic rear view showing an example of the appearance of the fixed component 5 of the trigger switch TS described in this application. Figure 16 In the fixing component 5 of the trigger switch TS illustrated herein, second fixing electrodes 51, made of multiple metal sheets, are arranged side-by-side along the moving direction of the first conductive plate 40. Furthermore, the electrode area of ​​the capacitor formed by the second fixing electrodes 51 and the first conductive plate 40 changes as the first conductive plate 40 moves. Thus, the second fixing electrodes 51 can also be formed using multiple metal sheets, and the electrode area can be arranged and shaped to increase or decrease as the first conductive plate 40 moves. In other words, the trigger switch TS of the present invention can be formed in various configurations and shapes as long as the electrode area of ​​the capacitor formed with the first conductive plate 40 changes as the first conductive plate 40 moves.

[0078] In addition, for example, in the embodiment described above, the first fixed electrode 50 and the second fixed electrode 51 are used as electrodes to form the first capacitor with the first conductive plate 40. However, the present invention is not limited to this and can be extended to various other ways, such as using only the triangular-shaped second fixed electrode 51.

[0079] Furthermore, as in the described embodiment, the change in the driving method performed by the switching lever 3 indicates switching the rotation direction of the drive unit M, i.e., the motor, to either forward or reverse rotation. However, the present invention is not limited to this and can be used for switching various driving methods. For example, it can be expanded to various modes such as switching the switching lever 3 of the trigger switch TS of the present invention, switching to a variable speed mode where the output changes according to the amount of pressing the trigger 1, or a constant speed mode where the output remains constant regardless of the amount of pressing the trigger 1.

[0080] Furthermore, in the embodiment described above, a first detection unit 56, a second detection unit 57, a control unit 55, and an output unit 58 are provided in the trigger switch TS. However, the present invention is not limited to this and can be extended to various ways, such as setting the control unit 55 outside the housing 2 of the trigger switch TS, or inside the main device MU.

[0081] Explanation of reference numerals in the attached figures

[0082] TS trigger switch; 1 trigger; 2 housing; 3 switching lever (operating component); 321 second conductive plate (secondary movable electrode); 4 movable component; 40 first conductive plate (movable electrode); 5 fixed component; 50 first fixed electrode; 51 second fixed electrode (fixed electrode); 52 third fixed electrode; 53 fourth fixed electrode (secondary fixed electrode); 55 control unit; 56 first detection unit; 57 second detection unit; 58 output unit; 6 engaging component; ET electric device; MU main body device; M drive unit

Claims

1. A trigger switch for power tools, comprising a trigger that moves in response to a pressing operation, characterized in that it has: Operating components, which receive commands and act accordingly; A movable electrode, which is plate-shaped along the direction of movement of the trigger, moves with the movement of the trigger caused by the pressing operation; A fixed electrode, which is plate-shaped along the moving direction of the trigger, is disposed near the moving range of the movable electrode and forms a capacitor with the movable electrode; A secondary movable electrode that moves with the movement of the operating component; A secondary fixed electrode, which forms a capacitance with the secondary movable electrode when the secondary movable electrode is located nearby; The movable electrode is isolated from the fixed electrode. The capacitance of the capacitor formed by the movable electrode and the fixed electrode changes as the movable electrode moves. As the operating component moves, the secondary movable electrode moves between a position where it forms a capacitor with the secondary fixed electrode and a position where it does not form a capacitor.

2. The trigger switch as described in claim 1, characterized in that, The fixed electrode is formed in a shape that changes according to the position of the movable electrode within its range of motion, thereby changing the electrode area that forms the capacitor.

3. The trigger switch as described in claim 2, characterized in that, The fixed electrode is formed in a shape in which the electrode area forming the capacitor gradually increases along the movement direction based on the pressing operation.

4. The trigger switch as described in any one of claims 1 to 3, characterized in that, It can be assembled in an electric device having a drive unit driven by an electrical signal. It also has an output unit that outputs an electrical signal to drive the drive unit. The output unit outputs an electrical signal that drives the drive unit, corresponding to the capacitance of the capacitor formed by the movable electrode and the fixed electrode.

5. The trigger switch as described in any one of claims 1 to 3, characterized in that, It can be assembled in an electric device having a drive unit driven by an electrical signal. It also has an output unit that outputs an electrical signal to drive the drive unit. The output unit performs the following actions. An electrical signal is output to drive the drive unit, corresponding to the capacitance of the capacitor formed by the movable electrode and the fixed electrode. Based on the capacitance of the capacitor formed by the secondary movable electrode and the secondary fixed electrode, an electrical signal representing the driving method of the driving unit is output.

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