JP2010082764A - Electric hammering machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small lightweight electric impact tool. <P>SOLUTION: The electric impact tool is provided with: a housing; a trigger switch operated by a user; a motor installed on the housing; a magazine mounted on the housing and supplying nails to a hammering position; a plunger for hammering the nails; a compression spring biasing the plunger in the nail hammering direction; a compression release mechanism receiving rotation of the motor, moving the plunger in the accumulation direction of the spring to release the compression; a detection switch for detecting operation of the compression release mechanism; and a control circuit controlling driving of the motor based on an input of the trigger switch, thereby turning off a no-contact switch, based on an input of the detection switch immediately before hammering. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an impact tool, and more particularly to an electric driving machine.

  Spring-driven nailing machines have already been produced in which a spring-biased plunger is pushed up against a spring-biasing force and then released to drive a nail into a driven material with an accelerated plunger. A tool is known in which the plunger is pushed up by a motor, a reduction gear, and a mechanism built in the tool to reduce the effort for raising the plunger. Some of these tools have a function of shutting off the power supply to the electric actuator after hitting the fastener once and completing one cycle. For example, it is known that the motor current is turned off after measuring a preset standby time after detection by a cycle end detection switch that detects that the plunger has reached a predetermined position after being driven. There is also a method of stopping the motor using the output of a stop switch that detects that a predetermined rotation angle of the mechanism for pulling up the plunger has been reached.

  Further, it is known that these tools use a contact switch such as an inexpensive micro switch.

Japanese Utility Model Publication No. 7-33575

  However, when these tools are driven, a large vibration is generated because the plunger collides with the housing. This vibration may cause switch opening. In addition, when the motor is started with the switch turned on, a large inrush current of the motor flows.At this time, if the contact breaks due to the chattering of the switch, a large arc is generated between the contacts, and the contact is consumed. This leads to the problem of reduced switch life. Further, in the case of the battery drive type, since the direct current is cut off, the polarity becomes one direction, and there is a problem that the transition of the contact is likely to occur. It is an object of the present invention to prevent these problems and to provide a highly reliable small and lightweight electric impact tool.

A housing, a trigger, a magazine that is attached to the housing and supplies a nail to a driving side position, a plunger that drives the nail, a compressible spring that biases the plunger in the hitting direction of the nail, A motor provided in the housing; a drive member that moves the plunger in the direction of accumulating the spring in response to the rotation of the motor; a contact switch that is turned on / off by the operation of the trigger; and a non-contact that controls the drive of the motor In the electric driving machine having a switch means and a control circuit for controlling the contactless switch means, the contact switch, the motor and the contactless switch are configured in series with respect to a power source, and the plunger Providing a first detection means for detecting a timing immediately before starting the operation of driving the nail, and the control circuit is configured to detect the contact switch. Turning on said non-contact switching means based on the force, by the turning off of the proximity switch means before starting the driving operation on the basis of the output of the first detecting means, can be solved.
Further, when the contactless switch is turned on based on the input of the contact switch, the control circuit can be solved by turning on the contactless switch after a predetermined delay time has elapsed from the input of the contact switch. .
Furthermore, it is preferable that the set time of the delay time is between 1 ms and 10 ms.

  According to the electric striking tool of the present invention, even if the contact of the trigger switch is released due to vibration at the time of driving, the contactless switch is turned off before that, and no current flows through the motor. There is no spark between the contacts. Furthermore, since the timing for turning off the contactless switch is before the start of the driving operation, but immediately before, the driving operation is performed due to the inertia of the mechanism section. Further, even when the driving operation is started, no spark is generated between the contact points of the trigger switch by turning on the contactless switch after the trigger switch is turned on and the chattering of the contact is settled. Therefore, contact wear of the trigger switch can be reduced and the life can be improved.

  Hereinafter, an electric driving machine according to an embodiment of the present invention will be described with reference to FIGS. First, the overall configuration of the driving machine 1 according to the present embodiment will be described with reference to FIGS. FIG. 1 is a cross-sectional view of the driving machine 1. The driving machine 1 includes a housing 2, a handle 3, a battery 4, a nose 5, a magazine 6, a trigger 10, and a controller 100.

  The housing 2 is provided with a plunger 8 serving as a hitting projection, a spring 9, a motor 7, a speed reduction mechanism 11, a gear 14, a guide plate 18, a drum 13, a wire 16, a stop switch 25, and the like.

  The plunger 8 is disposed so as to be movable between the top dead center side and the bottom dead center side of the housing 2. The plunger 8 has a blade 8 a, and the tip of the blade 8 a extends to a passage position defined in the nose 5. Further, a disc-shaped plunger plate 8b is installed on the top dead center side of the end portion of the plunger 8, and its substantially center is connected to the top dead center side tip of the blade 8a. The nail disposed in the passage in the nose 5 with the plunger 8 positioned at the top dead center is pushed out from the tip of the nose 5 by the blade 8a when the blade 8a moves toward the bottom dead center, It will be driven into the member.

  The spring 9 is installed between the plunger plate 8b and the left end of the housing 2 in FIG. The motor 7 includes a rotating shaft (not shown), rotates with the electric power supplied from the battery 4, and supplies a rotational force to the speed reduction mechanism 11. The speed reduction mechanism 11 includes a motor 7, a pulley (not shown), a belt, and a gear that are attached to one end of the rotation shaft of the motor 7, and applies a rotational force to the output shaft 19 (see FIGS. 2 (a) to 2 (c)). Output. Since the torque of the motor 7 can be amplified by the speed reduction mechanism 11, the small motor 7 is used for the compression mechanism of the spring 9.

  The drum 13 rotates based on the operation of a compression release mechanism (clutch mechanism) described later by the rotational force supplied from the motor 7 via the speed reduction mechanism 11. The wire 16 connects the drum 13 and the plate 8 b of the plunger 8. The wire 16 is a bundle of a plurality of metal wires, and has both flexibility and strength. Further, in order to prevent wear due to contact with the drum 13, the surface of the wire 16 is coated with a resin.

  The handle 3 extends from the surface of the housing 2, and a trigger 10 for controlling the operation of the motor 7 is provided at the upper left boundary in FIG. 1. A trigger switch 24 is provided in the handle 3 so as to operate adjacent to and in conjunction with the trigger 10. The controller 100 is installed in the housing 2, and the battery 4 is detachably provided at the end of the handle 2. The battery 4 supplies electric power to the motor 7 via the controller 100 by wiring (not shown) arranged in the handle 3.

  The magazine 6 is provided across the nose 5 and the tip portion of the housing 2. A plurality of nails (not shown) are built in a bundle in the magazine 6, and the nails are supplied into the passage of the nose 5. The distance of the passage in the nose 5 is ensured to be larger than the nail length, and constitutes a running section for accelerating the plunger 8 until the nail contacts the driven member.

  Next, the configuration of the clutch that serves as a compression release mechanism for the spring 9 will be described with reference to the developed views of FIGS. 2 (a) to 2 (c). The compression release mechanism of the spring 9 includes a speed reduction mechanism 11, an output shaft 19 of the speed reduction mechanism 11, a gear 14, a guide plate 18, a pin support plate 21, a drum hook 22, a drum 13, a power transmission pin 17 as a moving unit, and a drum 13. , And a wire 16.

  As shown in FIG. 2C, the gear 14 has a substantially disk shape, and the center portion is a fitting hole portion 14b having a two-sided width portion. A plurality of through holes 14c are provided around the fitting hole 14b. Moreover, the extension part 14a is provided over the periphery of the upper surface in FIG.2 (c) of the gear 14 over about 270 degree | times along the circumference. The gear 14 is fixed to the output shaft 19 by fitting a not-shown two-sided width portion provided in the output shaft 19 into a fitting hole 14b. The through hole 14c is provided for reducing the weight of the gear 14 and reducing inertia. The extension part 14a is provided to turn on or off the stop switch 25 depending on whether or not it engages with a stop switch 25 described later.

  The guide plate 18 is formed with guide grooves 18a, guide protrusions 18b, and through holes (not shown). The through hole is formed substantially at the center of the guide plate 18, and the output shaft 19 is inserted therethrough. The output shaft 19 has an outer shape that is cut into a two-sided width, and has a shape that fits into a through hole 21b of a pin support plate 21 described later. The guide groove 18a is formed adjacent to the through hole, and the guide protrusion 18b is formed around the through hole so that the distance from the through hole to the guide groove 18a is increased in a certain part. Specifically, the guide protrusion 18b has a shape that is expanded about 5 to 15 mm in the radial direction from the center of the through hole.

The stop switch 25 has a substantially rectangular parallelepiped shape and has an opening / closing portion that is turned on or off by opening / closing. The stop switch 25 is sandwiched between the upper surface of the outer periphery of the gear 14 and the lower surface of the protrusion 18b of the guide plate 18 in FIGS. 2 (a) to 2 (c), and is attached to the guide plate 18 by screws (not shown). It is fixed. The thickness of the stop switch 25 in the direction of the output shaft 19 is substantially equal to the height of the extending portion 14 a of the gear 14. The opening / closing part of the stop switch 25 is fixed at a position where the presence or absence of engagement with the extending part 14 a changes according to the rotation of the gear 14.

  The pin support plate 21 is formed with a through hole 21b cut out in a two-sided width shape in the main body portion, and an extending portion having a pin support slide portion 21a extends from the main body portion. The through hole 21b fixes the pin support plate 21 to the output shaft 19 by engaging with a notch of the output shaft 19 inserted through the through hole 21b.

  The power transmission pin 17 includes a guide groove contact portion 17a and a pin contact portion 17b. The guide groove contact portion 17 a can be engaged with the guide groove 18 a of the guide plate 18. Therefore, the moving direction and moving amount of the power transmission pin 17 are controlled by the shape of the guide groove 18a. The pin contact portion 17b has the same height as a hook portion 22a of a drum hook 22 described later in a state where the compression release mechanism is combined.

  With such a configuration, the pin support plate 21 and the power transmission pin 17 always rotate in synchronization with the output shaft 19.

  The drum hook 22 includes a cylindrical main body portion and a hook portion 22a extending from the side surface of the main body portion. A bearing is disposed on the inner peripheral surface of the main body. Since the output shaft 19 is inserted into the drum hook 22 via a bearing, the output shaft 19 and the drum hook 22 do not necessarily rotate in synchronization. The hook portion 22 a extends from the main body portion in a direction substantially perpendicular to the output shaft 19, and can contact the pin contact portion 17 b of the power transmission pin 17. Accordingly, the power transmission pin 17 always rotates in synchronization with the pin support plate 21. However, the drum hook 22 is only in the case where the pin contact portion 17b of the power transmission pin 17 contacts the hook portion 22a. It rotates in synchronization with the support plate 21 and the power transmission pin 17.

  The drum 13 has an annular shape. The body portion of the drum hook 22 is press-fitted into the through hole formed at the approximate center of the drum 13. Thereby, the drum 13 and the drum hook 22 rotate in synchronization. The damper collision portion 13 a is provided so as to protrude from the drum 13 in the axial direction of the output shaft 19.

  The wire 16 is disposed so as to be able to be wound around the side surface of the drum 13, and connects the drum 13 and the plunger 8 (see FIG. 1), and is wound around the side surface according to the rotation of the drum 13. The plunger 8 is moved.

  Next, the operation at the time of nailing will be described with reference to FIGS. 3A to 3E which are operation diagrams of the spring compression release mechanism. In the initial state of the driving machine 1, the plunger 8 is located at the bottom dead center. When the operator pulls the trigger 10, electric power is supplied from the battery 4 to the motor 7 by the trigger switch 24 and the controller 100, and the motor 7 rotates. The rotational force is transmitted to the pin support plate 21 and the power transmission pin 17 via the speed reduction mechanism 11 and the output shaft 19.

  FIG. 3A shows an initial state of the spring compression release mechanism. When the pin contact portion 17b and the hook portion 22a are in contact with each other, the power transmission pin 17 and the drum hook 22 are engaged and moved simultaneously. It has become. Therefore, the pin support plate 21 rotates and the drum hook 22 and the drum 13 also rotate. The opening / closing part 25a of the stop switch 25 is provided at a position of about 90 degrees clockwise with respect to the contact surface between the pin contact part 17b and the hook part 22a in the initial state. Further, in the initial state, the extended portion 14a of the gear 14 is in a state of being arranged over about 260 degrees counterclockwise from the contact surface. At this time, the opening / closing portion 25a of the stop switch 25 is in a closed state by engaging with the extending portion 14a of the gear 14, and is turned on immediately after the trigger switch 24 is turned on.

  FIG. 3B shows a state in which the pin support plate 21 is rotated approximately 180 degrees counterclockwise from the state of FIG. In synchronization with the rotation of the pin support plate 21, the drum 13 is also rotated 180 degrees, and one end of the wire 16 is wound around the drum valley 13b. When the wire 16 is wound, the plunger 8 connected to the other end of the wire 16 is pulled and moved toward the top dead center, and the plunger plate 8b provided at the end of the plunger 8 compresses the spring 9. At this time, the stop switch 25 remains on.

  As the pin support plate 21 rotates from FIG. 3 (b) to FIG. 3 (d), the guide protrusion 18 b installed in the guide groove 18 a and the end of the power transmission pin 17 come into contact. The guide protrusion 18b has a shape that swells about 5 to 15 mm in the radial direction from the center of the rotation axis. As the pin support plate 21 rotates, the power transmission pin 17 follows the shape of the guide protrusion 18b and the pin support slide. It moves radially outward along the portion 21a.

  When the pin support plate 21, that is, the drum 13 is rotated by about 270 degrees from the state shown in FIG. 3A to the state shown in FIG. 3C, the extending portion 14a is disposed in the opening / closing portion of the stop switch 25. The engagement is released by reaching the nonexistent portion, and the stop switch 25 is turned off. As will be described later, when the stop switch 25 is turned off by the action of the controller 100, the power supply to the motor 7 is stopped. However, the drum 13 continues to rotate due to the rotational inertia of the motor 7, the speed reduction mechanism 11, the drum 13, the gear 14, and the output shaft 19.

  When the pin support plate 21, that is, the drum 13 is rotated about 270 degrees from the state shown in FIG. 3A to the state shown in FIG. 3D, the plunger 8 moves to the top dead center, and the spring 9 is the most. It is in a compressed state. At this time, the top nail stored in the magazine 6 is loaded into the injection path by being pressed by a feeding member (not shown). At the same time, the power transmission pin 17 moves about 5 to 15 mm radially outward, and the engagement between the power transmission pin 17 and the hook portion 22a is released. At this time, no current flows through the motor 7.

  When the engagement between the power transmission pin 17 and the hook portion 22a is released, the compressed spring 9 is released and the plunger 8 moves to the bottom dead center side. When the plunger 8 moves to the bottom dead center side, it is pulled by the wire 16 and the drum 13 and the drum hook 22 start reverse rotation (FIG. 3 (d)). On the other hand, the gear 14 further rotates in the counterclockwise direction of FIG.

  When the plunger 8 reaches the bottom dead center by the opening force of the compressed spring 9, the nail 23 in the injection path 5a of the nose 5 is pushed out from the tip of the nose 5 by the blade 8a and driven into the material to be driven. At the same time, the plunger 8 collides with a damper (not shown) fixed at the housing 2 at the bottom dead center. When the drum 13 returns to the initial state, the damper collision portion 13a engages with a drum damper (not shown) fixed in the housing 2, and the drum 13 and the drum hook 22 are fixed at the initial position. When the plunger 8 and the drum collision part 13a collide, the impact propagates through the housing 2 to the entire driving machine 1. However, as described above, the stop switch 25 is turned off just before the nail is driven after the engagement between the power transmission pin 17 and the hook portion 22a is released, so that the FET 101 which is a contactless switch of the controller 100 is turned off. The power supply from 4 to the motor 7 is stopped. Therefore, since a large current does not flow through the trigger switch 24, an arc does not fly between the contacts even if the contacts of the trigger switch 24 are separated due to the impact at the time of the collision, and the contact life is not shortened. Further, the gear 14 further rotates and the stop switch 25 is engaged with the extending portion 14a again, so that it is turned on.

  The operation of the stop switch 25 will be described collectively. In the initial state, the opening / closing portion 25b is closed by the extending portion 14a of the gear 14, and the stop switch 25 is turned on immediately after the trigger switch 24 is turned on. If the drum 13 rotates to about 260 degrees while the stop switch 25 is kept on, the extension portion 14a of the gear 14 and the stop switch 25 are disengaged and turn off. When the drum 13 further rotates to about 270 degrees due to the rotation inertia, the power transmission pin 17 and the hook portion 22a are disengaged, and the drum 13 starts reverse rotation and performs a driving operation. Then, due to the rotational inertia, the gear 14 further rotates, rotates to around 0 degrees, and returns to the state of FIG.

  Next, the configuration of the controller 100 will be described with reference to FIG. 4 which is a circuit diagram. The controller 100 includes a non-contact energizing switch FET 101, a PNP transistor 110, an NPN transistor 111, a PNP transistor 115, a capacitor 114, a capacitor 121, a stop switch 25, and a failure state detection circuit 140. In this embodiment, an Nch FET is used as the FET 101.

  The FET 101 is connected in series with the battery 4, the trigger switch 24, and the motor 7. A resistor 103 is connected between the gate and source of the FET 101. A resistor 102 is further connected to the gate of the FET 101. The resistor 102 is connected to the ground via the remaining amount detection switch 26. The remaining amount detection switch 26 is a switch for detecting the remaining amount of the nail in the magazine 6, and is configured to be turned off when the remaining amount of the nail is larger than a predetermined number, and to be turned on when the number is less than the predetermined number. Yes.

  Between the terminals of the motor 7, a diode 104 that suppresses the generation of flyback voltage is connected. Further, a smoothing circuit including a resistor 105 and a capacitor 106 is connected to the high-voltage side terminal of the motor 7, and an output side of the smoothing circuit is connected to the gate of the FET 101 via the resistor 107 and the resistor 102. Yes. Thus, when the trigger switch 24 is turned on, a smooth voltage is applied to the gate of the FET 101, so that the FET 101 is also turned on and a current flows through the motor 7.

  The output side of the smoothing circuit is also connected to the emitter of the PNP transistor 110. A resistor 109 and a capacitor 142 are connected in parallel between the base and emitter of the PNP transistor 110. Further, the base of the PNP transistor 110 is connected to the collector of the NPN transistor 111 via the resistor 108, and the collector of the PNP transistor 110 is connected to the base of the NPN transistor 111 via the resistor 113. A resistor 112 and a capacitor 114 are connected in parallel between the base and emitter of the NPN transistor 111. The emitter of the NPN transistor 111 is further connected to the negative terminal of the battery 4. The collector of the NPN transistor 111 is connected to the gate of the FET 101 via the resistor 102. Here, the output side of the resistor 108 is referred to as point A. Point A is further connected to the ground via a capacitor 141.

  The output side of the smoothing circuit is also connected to one end of the stop switch 25. The other end of the stop switch 25 is connected to the negative terminal of the battery 4 via the resistor 122. Further, a backflow preventing diode 118, a resistor 119, and a capacitor 121 are connected in series between the other end of the stop switch 25 and the negative terminal of the battery 4. The output side of the resistor 119 is further connected to the emitter of the PNP transistor 115. A resistor 116 is connected between the base and emitter of the PNP transistor 115, and the base of the PNP transistor 115 is further connected to the other end of the stop switch 25 via a resistor 117 and a diode 120. The collector of the PNP transistor 115 is connected to the collector of the PNP transistor 110.

  The failure state detection circuit 140 includes an operational amplifier 130, resistors 123, 125, 126, 127, 128, diodes 125, 129, 131, and a capacitor 124. A voltage obtained by dividing the smoothed voltage by the resistor 126 and the resistor 127 is applied to the non-inverting input terminal of the operational amplifier 130 and is connected to one end of the stop switch 25 via a diode 132. The non-inverting input terminal is connected to the output terminal of the operational amplifier 130 via the resistor 128 and the diode 129. The resistor 128 and the diode 129 form a Schmitt trigger circuit that performs positive feedback. The inverting input terminal is connected to the gate resistance 102 of the FET 101 via the resistor 123 and further connected to the ground via the capacitor 124, and the capacitor 124 is charged via the resistor 123. Further, the inverting input terminal is connected to the smoothing voltage via the diode 125. The output terminal of the operational amplifier 130 is connected to the gate resistor 102 of the FET 101 via a diode 131. Although not shown, a smoothing voltage is applied as a power source for the operational amplifier 130.

The operation of the controller 100 configured as described above will be described with reference to operation time charts of FIGS. 5 and 7. FIG. 7 shows an enlarged view at time t = t0 to t1 in FIG. As shown in FIG. 7, when the trigger switch 24 is turned on at time t = t0, the voltage smoothed by the resistor 105 and the capacitor 106 is applied to the point A via the resistor 107, the capacitor 142, and the resistor 108. As the capacitor 141 charges, the potential at the point A rises gently. At the same time, since the point A potential is also applied to the gate of the FET 101, the FET 101 is turned on after the time Td when the point A potential exceeds Vth which is a threshold value for turning on the FET, and current is supplied to the motor 7. Start flowing. In order to prevent the PNP transistor 110 from being turned on only by turning on the trigger switch 24, the resistor 103 has a value sufficiently larger than the resistors 108 and 109 (for example, about 10 times).
The trigger switch 24 is a contact type switch, and even when the switch is turned on at time t = t0, chattering occurs due to the bounce of the contact, and the switch is turned on and off during the Tch time and then turned on. This chattering time Tch is usually 0.5 to several milliseconds. Even if chattering of the trigger switch 24 occurs, the trigger switch 24 is set to a time Td from the time when the trigger switch 24 starts to turn on (t = t0) to the time when the current starts to flow after the FET 101 turns on. At the contact point, since the large current flowing through the motor 7 is not cut and the arc does not fly, the contact life can be extended. The time Td is preferably 1 to 10 milliseconds. The capacitor 142 is a capacitor for bypassing the base current of the PNP transistor 110 so as not to turn on the PNP transistor 110 while the capacitor 141 is being charged.

FIG. 8 shows a waveform when the capacitors 141 and 142 are not provided. In this case, the potential at the point A rises rapidly, and the FET 101 is turned on before the chattering time Tch elapses, and an arc is generated by chattering of the trigger switch 24 (FIG. 8, hatched portion).
When the FET 101 is turned on and a current starts to flow through the motor 7, the motor 7 rotates and the pin support plate 21 and the drum 13 also start rotating. In addition, as described above, the opening / closing portion of the stop switch 25 is turned on because it engages with the extending portion 14a of the gear 14 (t = t1).

  When the stop switch 25 is turned on immediately after the trigger switch 24 is turned on, the capacitor 121 is charged via the diode 119 and the resistor 116. The stop switch 25 is turned on when the rotation angle of the drum 13 is about 0 to about 270 degrees, during which the emitter potential of the PNP transistor 115 is lower than the cathode potential of the diode 120 and the base of the PNP transistor 115 There is no potential difference between the emitters to turn on the PNP transistor 115, so the PNP transistor 115 remains off.

  On the other hand, when the FET 101 is turned on, the voltage across the resistor 127 when the smoothed voltage is divided by the resistor 126 and the resistor 127 is applied to the non-inverting input terminal of the operational amplifier 130 (t = t0).

  Here, an example of setting the resistance values of the resistors 126 to 128 will be described. The voltage divided by the resistor 126 and the resistor 127 and input to the non-inverting input terminal of the operational amplifier 130 is, for example, about ½ of the smoothed voltage. This is possible by setting the resistance 126 and the resistance 127 to the same value.

  Subsequently, when the stop switch 25 is turned on (t = t1), a smoothing voltage is input to the non-inverting input terminal of the operational amplifier 130 via the stop switch 25 and the diode 132. When the trigger switch 24 is turned on, a smooth voltage is applied via the resistor 107 and the resistor 123, and the capacitor 124 is charged. Therefore, the voltage of the capacitor 124 is applied to the inverting input terminal. At this time, even if the capacitor 124 is charged, the voltage is always lower than the smoothing voltage, so that a high output is output to the output terminal of the operational amplifier 130. This high output is blocked by the diode 131.

  When the rotation angle of the drum 13 reaches about 260 degrees (FIG. 3C), the stop switch 25 is turned off as described above (t = t2).

When the stop switch 25 is turned off, the voltage applied to the non-inverting input terminal of the operational amplifier 130 is a voltage applied to the resistor 127 when the smoothed voltage is divided by the resistor 126 and the resistor 127. At this time, since the input voltage to the non-inverting input terminal is lower than the input voltage to the inverting input terminal, the output of the operational amplifier 130 is a low output. At the same time, a current also flows through the resistor 128 by the diode 129, and the input voltage at the non-inverting input terminal further decreases. Further, the low output of the operational amplifier 130 turns off the FET 101 by setting the voltage at point A to 0 volts, so that no current flows through the motor 7. Thus, when the stop switch 25 is turned off, the drive of the motor 7 is stopped. (T = t2)
At this time, that is, when the voltage at the point A becomes 0 V due to the output of the operational amplifier 130, both the PNP transistor 110 and the NPN transistor 111 are turned on, as will be described later. Then, the A point voltage of 0 volts is continued. Then, the inverting input voltage discharges the capacitor 124 through the resistor 123, so that the inverting input voltage gradually decreases and becomes lower than the non-inverting input terminal voltage. (T = t3). At this time, the non-inverting input terminal voltage becomes a divided voltage of the resistor 126 and the resistor 127, and the output voltage of the operational amplifier 130 becomes a high output, but is blocked by the diode 131, and further, the operation of the PNP transistor 110 and the NPN transistor 111. Therefore, the voltage at point A continues at 0 volts.

  Further, when the stop switch 25 is turned off, the base of the PNP transistor 115 is connected to the GND potential via the resistor 117, the diode 120, and the resistor 122. Therefore, the emitter of the PNP transistor 115 connected to the charged capacitor 121 is A potential difference occurs between the two. As a result, the PNP transistor 115 is turned on, and the charge accumulated in the capacitor 121 flows into the capacitor 114 via the resistor 113.

  When the capacitor 114 is charged, the base potential of the NPN transistor 111 rises, and the NPN transistor 111 is turned on. When the NPN transistor 111 is turned on, the potential at the point A becomes GND, and the potential of the gate of the FET 101 also becomes the GND potential, so that the FET 101 is turned off and no current flows through the motor 7.

  Here, when the NPN transistor 111 is turned on, the base of the PNP transistor 110 is also connected to the GND potential via the resistor 108, so that the PNP transistor 110 is also turned on. As a result, as long as the trigger switch 24 is on, a smoothing voltage is applied to the base of the NPN transistor 111, and the NPN transistor 111 is kept on. Therefore, once the NPN transistor 111 is turned on, the NPN transistor 111 can be kept in the on state, that is, the FET 101 can be kept off even if all the electric charge stored in the capacitor 121 is discharged. In addition, it is desirable to make the capacity of the capacitor 121 larger than the capacity of the capacitor 114.

  If the trigger switch 24 is turned off, the PNP transistor 110 is turned off, so that the holding of the off state of the FET 101 can be released. Then, when the trigger switch 24 is turned on again, the FET 101 can be turned on and the motor 7 can be started.

  With the above operation, the driving machine 1 can perform the nail driving operation, and after the single hitting operation is completed, the FET 101 is turned off to realize a single driving operation.

  Next, an operation when the stop switch 25 does not work due to a failure or the like will be described with reference to FIGS. 4 and 6. The stop switch 25 may fail, such as being unable to press the stop switch 25 due to a mechanical failure, or being unable to switch due to a mechanical or electrical failure. Do not perform the driving operation.

  When the trigger switch 24 is turned on (t = t10), after a slight delay time, the FET 101 is turned on and a current starts to flow through the motor 7. At the same time, the pin support plate 21 and the plunger 8 also start to operate. When the stop switch 25 is always in an off state due to a failure, the non-inverting input terminal voltage of the operational amplifier 130 is a voltage obtained by dividing the smoothed voltage by the resistor 126 and the resistor 127. The inverting input terminal voltage of the operational amplifier 130 becomes the voltage of the capacitor 124 that is charged through the resistor 107 and the resistor 123 by the smoothing voltage. As shown in FIG. 6, at t = t10, the voltage of the capacitor 124 is zero, and the voltage input to the non-inverting input terminal is larger than the voltage of the inverting input terminal, so that the output of the operational amplifier 130 is a high output. . At that time, the output voltage of the operational amplifier 130 is blocked by the diode 129 and the diode 131.

  Subsequently, the voltage of the capacitor 124 gradually increases by charging, and the voltage of the inverting input terminal exceeds the voltage of the non-inverting input terminal at t = t11. At this time, the output of the operational amplifier 130 becomes a low output. At the same time, a current also flows through the resistor 128 by the diode 129, and the input voltage at the non-inverting input terminal decreases. (T = t11) When the point A voltage becomes 0 volt, the point A voltage of 0 volt is continued by the action of the PNP transistor 110 and the NPN transistor 111 as described above. Then, the inverting input voltage discharges the capacitor 124 through the resistor 123, so that the inverting input voltage gradually decreases and becomes lower than the non-inverting input terminal voltage. (T = t12). At this time, the non-inverting input terminal voltage becomes a divided voltage of the resistor 126 and the resistor 127, and the output voltage of the operational amplifier 130 becomes a high output, but is blocked by the diode 131, and further, the operation of the PNP transistor 110 and the NPN transistor 111. Therefore, the voltage at point A continues at 0 volts.

  As an example, the value of the positive feedback resistor 128 is divided by the parallel combined resistance value of the resistor 127 and the resistor 128 and the resistor 126 so that the voltage input to the non-inverting input terminal is 1 / Try to be around 3.

  The low output of the operational amplifier 130 reduces the gate voltage of the FET 101 to 0 V through the gate resistor 102 to turn off the FET 101 and cuts off the current of the motor 7 in order to make the voltage at the point A through the diode 131 0 volts. . Here, by combining the resistance value of the resistor 123 and the capacitance of the capacitor 124, the time t = t11 is set longer than t1 and sufficiently short (for example, about 30 ms) to stop the impact operation. Is preferred.

  As described above, according to the driving machine 1 according to the present embodiment, the FET 101 that is a contactless switch is turned on after the delay time Td that is longer than the chattering time Tch that occurs when the trigger switch 24 is turned on. In this way, since the large current of the motor 7 is cut off at the contact of the trigger switch 24 by chattering and no arc is generated, the life of the trigger switch contact can be extended.

  Furthermore, since the driving machine 1 according to the present embodiment turns off the FET 101, which is a contactless switch, immediately before the plunger 8 drives the nail and starts driving with the rotational inertia of the mechanism, the driving operation of the plunger 8 Even if the contact of the trigger switch 24 is separated due to the impact of time, since the large current of the motor 7 does not flow as described above, the arc does not fly between the contacts, and the life of the contacts can be extended.

  As described above in detail, according to the electric driving machine of the present invention, the contact life can be improved. That is, a simple, reliable, and inexpensive electric driving machine can be provided.

  The driving machine according to the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made within the scope described in the claims. For example, the circuit of the controller 100 that controls the motor is not limited to that shown in the present embodiment, and the scope of the present invention is within the scope of the present invention as long as the same function and effect can be obtained.

  In the above embodiment, the time constant circuit of the capacitor and the resistor is used to generate the delay time Td. However, the function may be substituted by a microcomputer.

In the electric driving machine by one embodiment of the present invention, the partial see-through side view showing when the plunger reaches the bottom dead center The perspective view of the spring compression release mechanism by one Embodiment of this invention. The perspective view which expanded the spring compression release mechanism by one Embodiment of this invention partially The perspective view which fully developed the spring compression release mechanism by one Embodiment of this invention. The perspective view of the spring compression release mechanism which removed the drum by one Embodiment of this invention The perspective view of the spring compression release mechanism which removed the drum by one Embodiment of this invention The perspective view of the spring compression release mechanism which removed the drum by one Embodiment of this invention The perspective view of the spring compression release mechanism which removed the drum by one Embodiment of this invention The perspective view of the spring compression release mechanism which removed the drum by one Embodiment of this invention The circuit diagram of the controller by one Embodiment of this invention. The operation | movement time chart of the controller by one Embodiment of this invention. The operation | movement time chart of the controller by one Embodiment of this invention. The operation | movement time chart of the controller by one Embodiment of this invention. The operation time chart of the controller by one Embodiment of a prior art example.

Explanation of symbols

1: Nailer 2: Housing 3: Handle 4: Battery 5: Nose 6: Magazine 7: Motor 8: Plunger 8a: Blade 8b: Plunger plate 9: Spring 10: Trigger 11: Reduction mechanism 12: Damper 13: Drum 13a : Drum damper collision part 13b: Drum trough part 14: Gear 16: Wire 17: Power transmission pin 17a: Pin slide part 17b: Pin hook part 18: Guide plate 18a: Guide groove 18b: Guide protrusion 19: Output shaft 20: Key 21: Pin support plate 21a: Pin support slide part 21b: Key groove 22: Drum hook 22a: Hook part 23: Nail 24: Trigger switch 25: Stop switch 100: Controller

Claims (4)

A housing;
Trigger,
A magazine which is attached to the housing and supplies nails to the driving side position;
A plunger for driving the nail;
A compressible spring that biases the plunger in the direction of striking the nail;
A motor provided in the housing;
A drive member that receives the rotation of the motor and moves the plunger in the direction of energy storage of the spring;
A contact switch that is turned on and off by the operation of the trigger;
Contactless switch means for controlling the driving of the motor;
In the electric driving machine having a control circuit for controlling the contactless switch means,
The contact switch, the motor, and the contactless switch are configured in series with a power source,
Providing a first detection means for detecting a timing immediately before the plunger starts to drive the nail;
The control circuit turns on the contactless switch means based on the input of the contact switch, and turns off the contactless switch means before the driving operation starts based on the output of the first detection means. Electric driving machine. A housing;
Trigger,
A magazine which is attached to the housing and supplies nails to the driving side position;
A plunger for driving the nail;
A compressible spring that biases the plunger in the direction of striking the nail;
A motor provided in the housing;
A drive member that receives the rotation of the motor and moves the plunger in the direction of energy storage of the spring;
A contact switch that is turned on and off by the operation of the trigger;
Contactless switch means for controlling the driving of the motor;
In the electric driving machine having a control circuit for controlling the contactless switch means to turn on the contactless switch means based on the input of the contact switch,
The contact switch, the motor, and the contactless switch are configured in series with a power source,
The control circuit, when turning on the contactless switch based on the input of the contact switch, turns on the contactless switch after a predetermined delay time from the input of the contact switch Driving machine. The electric driving machine according to claim 4, wherein the delay time is between 1 millisecond and 10 milliseconds. Providing a first detection means for detecting a timing immediately before the plunger starts to drive the nail;
4. The electric driving machine according to claim 2, wherein the control circuit turns off the contactless switch unit before starting driving operation based on an output of the first detection unit. 5.

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