TWI361744B - Power tool - Google Patents

Description

1361744 IX. Description of the invention: [Technical field to which the invention pertains] The present invention relates to a fastener for driving a robot, such as a nail, a rivet, or a nail slanting cymbal to drive a 忒 staple 《 "more specifically, this The invention relates to a power tool having a control effect of a batch of Yuelu crying & i丄li, the controller has a control circuit, which is used according to, for example, a push button and a trigger switch "nggerswitch" The operation of the control circuit of the combustion type or the electronic power generation mechanism. [Prior Art] A common power tool for driving such fasteners is a portable tool, which has a battery and a clock ion. A battery or other auxiliary battery is used as a power source. For example, in Japan, the patent application announcement No. sH〇_64_9i49 'HEI + 3 and HEI + 48589, Japanese patent unexamined HEI-8-216052 and 2005-28568 a, UU3 Mbb8唬, and U.S. Patent Nos. 4'483'474 and 5,133,329, etc., disclose a portable combustion type power tool in which a small gas cylinder is placed The flammable gas contained is injected into the combustion chamber provided in the cylinder above the piston. ♦ When the switch and the trigger switch are operated, the ignition power supplied by the battery generates a spark to ignite the flammable gas and air in the combustion chamber. a mixture thereby driving the piston that is slidably supported in the cylinder such that a driver blade mounted on the piston strikes a nail or other fastener. With such a combustion type power tool, when the user The combustion chamber is formed by pressing the push lever so that it is in close proximity to a workpiece. In this state, the liquefied gas is injected into the combustion chamber from the gas cylinder. Moreover, a fan can be driven by activation of a push button that acts in conjunction with the push lever. The fan agitates and mixes the combustible gas and air in the combustion chamber. When the user dreams of triggering the switch at this time When powering a tool, the spark plug creates a spark that ignites the mixture of air and fuel and drives the piston. The driver blades mounted on the piston The fastener can be driven into a workpiece such as a piece of wood. The frame of the combustion chamber is maintained in contact with a hood for a predetermined period of time after combustion, and the combusted gas is discharged from the combustion chamber: after the gas is discharged, Closing a check valve to hermetically seal the combustion chamber. The pressure drop in the combustion chamber (referred to as thermal vacuum) due to the resulting temperature drop creates pressure between the top and bottom of the piston. The difference 'this can drive the piston to rise. Another portable power tool is an electronic power tool. For example, in Japanese Unexamined Patent Publication No. HEI_8_2Q5573, the electric power tool has a motor. a linear moving moon for driving a gas to rotate and convert the kinetic energy of the flywheel into a drive fastener. The bitb electronic power tool has a transmission mechanism such as a clutch for transmitting the rotational energy of the flywheel to an impact mechanism. The mechanism includes driver blades with nails or other fasteners to perform the fastener driving operation. The movement of the fasteners a τ g Α , the power tool typically includes a button switch for detecting when the smoke is pulled/closed to the workpiece, and - for guiding the large blade to drive the blade Trigger switch for the operation of the fastener. This type of motion 312ΧΡ/invention manual (supplement)/96 11/96132 curry 00丄/44 drives the fastener after touching the operation button switch, and at least one of the button switch and the trigger switch The structure is avoided in the composition. Therefore, 'this $ Ω Μ # β 〇 power tool when the normally open switch is switched from the OFF state; the tremor that occurs from the next day's ^ to prevent the grinding caused by the tremor 』 the life of the switch And 'because the I# can be obtained by mechanical switch, the controller can be constructed similarly to the conventional device, and the circuit structure is generally provided. [Embodiment] The power tool of the present invention. Fig. 1 is a block diagram of a controller provided in the power tool 6 of the present invention. The control 6Qa includes: - a driving circuit Η, a control composed of a micro-electric brain and the like Circuit a control circuit (6), a low-voltage/voltage power supply circuit 63, a self-holding circuit 64, a push button switch 65, a trigger switch 66, a display circuit 68, a battery including a battery, an ion battery or other auxiliary battery ( a battery pack), and a main power source switch 67. A first detecting circuit 65a is provided for detecting whether the button switch 65' has been operated and for inputting an nickname corresponding to the operation of the button switch 65 to the control Similarly, a second detecting circuit 66a is provided for detecting whether the trigger switch 66 has been operated and for inputting a signal corresponding to the operation of the trigger switch 66 into the control circuit 62. If the control circuit 62 corresponds to a low level input signal, for example, when the individual button switch 65 or the trigger switch 66 is operated, the first detecting circuit 65a or the second detecting circuit 66a can set a low signal (grounding bit). The input is to the control circuit 62. 312XIV invention specification (supplement) /96·11/96132686 13 electric = 9 by supplying a voltage of 72v to the drive by, for example, a rotor battery, for example: "such as a motor drive circuit Or ignition circuit). The voltage of the battery 69 is supplied to the second voltage and is adjusted to the operation circuit voltage 62 as the operating voltage. The road (tuning ^. power supply f circuit 63 includes a DC power supply stable power supply ^, and the straw is controlled by the input terminal 6% and is connected later

The output 'of the circuit 1 ^ 64' is used to output the low power M to the control circuit 62 or to stop the output. 'Temple: mode or during operation mode in which the control circuit 62 is not described later, iu, (d), (control signal), self-holding electric lightning path: 乂2疋 level supply a control signal to low voltage The power supply circuit fn is: an input terminal 63a for controlling the low voltage power supply path (n is outputting a low voltage to the control circuit 62 or a part of the driving power)

‘·,, power supply voltage. When a one-touch m control signal is received from the control circuit 62 and enters the low power consumption mode, the self holds power: F 2:, 2; reverses its steady state (for example, from the first steady state or to (4); - a function of the steady state "state", whereby the specified level of the control signal input to the terminal is inverted to supply a low voltage from the low-voltage I power supply circuit 63 to the control circuit 2 or local The drive circuit 6 thus enters the low power consumption mode corresponding to the trigger signal from the control circuit 62, and stops outputting the low voltage from the low voltage power supply circuit 63. For example, in the embodiment of the position power Guard described below, the self-holding circuit 64 can be made of - 312XP with a PNP transistor and _ transistor (invention) / 96·11 touch 32686 14 : Road Constructed, the individual bases are connected to the 1 1 crystal i, and the transistors are applied with the positive feedback effect to the other: in the embodiment of the burn-in power tool, it can be clear: the circumference 65 or the trigger Switch 66, and in-segment

The circuit 63 is in a stable state, and the low voltage power supply is supplied, and the operation mode (standby mode) is applied to the voltage (for example, 3.3V). Therefore j is the source of the supply. However, if the button _ ^ continues to operate normally, such as w or the trigger on_66 is not within the specified distance, then the self-holding circuit 64 switches to the 0N shape.

At one enters the low power secret mode, the low voltage control input terminal is lowered to the ground level, and the output voltage of the low power supply circuit 63 is set to be higher than

Hold the circuit β ί, such as: G V). In this way, the self-holding circuit 64 can prevent power consumption when not going. It is not necessary when the field does not use the power tool 6〇. If the main power supply switch 67 is turned off and switched back to be turned on at this time, the self 3 holding circuit 64 is switched back to the OFF state (the first stable state Rt;疋 Return to normal operation mode). If the key switch or trigger switch 66 is operated sequentially, the control circuit 62 can control the drive circuit 61 to perform a fastener driving operation. $发: One feature is that at least the key switch 65 or the trigger switch 构成 is composed of a normally closed mechanical switch. In the preferred embodiment 312XP / invention manual (supplement) / 96-ii / 96i32 coffee 15 1361744, the key switch 6 5 series connection 黾 4 4 66 66 - normally closed η off ... touch trigger switch 疋: _turn off. In other words, the switch that triggers the open (four) state is 〇Ν. The other-side button _ 5 is often _ off, which is the normal state of the switch when it is not operating. Since the trigger switch 66 is a normally closed switch, the path 66& includes an inverter circuit for inputting the low signal to the control circuit 62 when the trigger switch = i. According to the button

The signal level input to the control circuit 62 by the operation of the trigger switch 66 is a low signal (ground level). " However, since the key switch 65 is connected in series to the trigger switch (10), the first-determining circuit 65a is not provided with an inverter circuit, and when the key switch 65 is turned on, a low signal can be input to the control Inside circuit 62. • 3 Since at least one of the push switch 65 and the trigger switch 66 is constituted by a normally closed switch in the present invention, the power tool of the present invention can prevent the conventional power tool from being switched to the ON state when the normally open switch is switched to the ON state. The % tremor occurs in this, thereby eliminating wear caused by tremor and prolonging the life of the trigger switch 66. Moreover, since the intended purpose is obtained by a mechanical switch, the controller 60a can be constructed of a relatively inexpensive circuit structure as is known in the art. In the present invention, both the push switch 65 and the trigger switch 66 can simultaneously use a normally closed switch. Moreover, the push button switch 65 and the trigger switch 66 do not need to be connected in series, but can input signals into the control circuit 62 through the first detecting circuit 65a and the second extracting circuit 6 6a connected in parallel. Hereinafter, a preferred embodiment of the present invention applied to a combustion type power tool will be described (Supplement ygw 1/96132686 16 1361744. Example 2: Combustion type power plant according to a preferred embodiment of the present invention 9. The controller _ in the second two V; the combustion type of power " = = in the - orientation, used to drive the needle or other structure =; = direction, but 'the invention is not limited to any special The embodiment or the phantom is as shown in Fig. 2. The combustion type power tool (nail drive) (10) has a casing 14 forming a frame, and a cover 20 mounted on the top end of the casing 2. On the inner side of the casing 14 The combustion type power tool 9 is provided with a cylinder 4, a buffer 2, a piston 1〇, a driver blade 10a integrally formed with the piston 1〇, a fan 6, a motor 8, and a spark plug 9. - a gas injection tank 19 - a gas cylinder 7, a combustion chamber frame ^, and a head sleeve 20a. The outer casing 14 is provided with a handle u, a nose portion 1, a push rod 21, a bullet g 13 and a trigger Switch 12. As described below, the controller 100 is disposed in the magazine 3 for control The spark is generated in the plug 9. As shown in Fig. 3, the controller 1 includes a circuit board on which a microcomputer (arithmetic control circuit) 1 〇 1, a ' is used to adjust the voltage supplied from the battery 25 to be low. A voltage low voltage power supply circuit (regulator) 102, a spark for generating sparks in the spark plug 9, an ignition circuit 1A8, and a motor drive circuit 109 for driving the fan 6. The controller 100 is electrically Connected to components such as push button switch 23, trigger switch 12, and temperature sensor 5 (refer to FIG. 2), and receive electronic signals from this group 312XP/invention manual (supplement)/96-11/96132686, In order to charge the ignition energy storage, six thieves (ignition capacitor) C5, and generate a spark in the spark plug 9: start or control the rotation of the fan motor 8. The battery 25 is an auxiliary battery f group)'. A clock ion battery or the like is included and is disposed in the solid state of the handle η. The controller 100 is connected to the battery 25 and supplies power from the battery 25 through a main f power supply switch SW1.

The cylinder 4 and the head cover 20 are fixed to the inner side thereof with respect to the outer casing 14. The firing chamber frame 15 is coupled to the push rod 21 provided under the cylinder 4 in an axial direction of the outer casing I: the casing 14. The combustion chamber frame 15 is moved by the guidance of the double flying cylinder 4. In Fig. 2, the spring = month (i.e., 'in the direction of the nail driving the fastener" is pushed to push the combustion chamber frame 15.

When the push rod is pressed against the workpiece (9) such as a piece of wood, t is pushed upward with respect to the outer casing 14, and the combustion chamber frame a == 21 - moves toward the top end of the cylinder 4 to counter the bomb The cyanine 26 thus forms a combustion chamber 15a. More specifically, the combustion chamber is surrounded by a combustion chamber frame 15, a headgear, and a piston chamber and is used for combustion of a mixture of combustible gas and air. The sealing member 22 constituted by the ring ^ ^ is disposed at the top end of the cylinder 4 to push the bottom end of the 9 2 〇 a so as to hermetically seal the combustion chamber 15a. When the master 1 rises, the push button switch 23 composed of the normally open switch is turned on. ^ 10 is disposed on the inner side of the steam rainbow 4, and is vertically reciprocally movable therein through a sliding member 2 such as a G ring. At the bottom of the U #气气3, a check valve (not shown) for opening and closing this discharge 312XP / invention manual (supplement) / 96-11/96132686 10 i Ο 1J61744 槔 3, and for absorption Piston 1 〇 shock buffer 2. When the piston 1 〇 suddenly moves down to the bottom dead center and drives the nail 24 and strikes the damper 2, the damper 2 is deformed to absorb excess energy in the piston j 〇. Provided within the combustion chamber 15a is a fan 6 that is rotatable by a motor 8 disposed at the top of the headgear; a spark plug 9, which can be produced when the trigger switch 12 formed by the normally closed switch is closed in accordance with the present invention Spark

The body is injected into the crucible 19, and the flammable gas (liquefied gas) supplied from the gas_7 is injected; and the fin 16 protrudes radially inward from the combustion chamber... as a rib. Play E 13 and nose! It is integrally mounted on the cylinder 4 underneath the outer casing 14, the light 13 is provided with a nail 24, and the nose 1 is used to guide the nail 24 supplied from the bullet g 13 to the workpiece 29. In the resting position shown in Fig. 2, the oven kiss and the push pin 21 protrude from the lower end of the nose 1 by the pressing force of the magazine 26. +Shi

Under this circumstance, a gap 17 is formed in the upper end of the μ A mountain t + π / flying cylinder 1 2 3 4 5 6 of the cylinder 4 under the combustion chamber frame 15 combined with the push rod 21, and under the head cover 20a. A gap 18 is formed in the upper end of the combustion chamber frame Η 10 , _ permanent b. The piston 1 停止 stops in the cylinder 4 at Tf at the top dead center 〇 when the combustion type power tool 90 is in this makeup energy.士. ^ ^ Mine, 辂 状 , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , 如果 如果 如果 如果 如果 如果 如果 如果 如果 如果 如果 如果The pusher 21 will rise to oppose the spring 26, and 揪1, and the combustion chamber frame 15 will rise with the pusher 221. Therefore, close the 4 gaps 17 and 18 below the upper plate of the frame 1 5 in the 蚴悻3j, and form the burnt, usually 5^ to 15a, this combustion chamber is sealed by 6 312XP/invented Specification (Supplement) / 96, 11/96132686 19 1361744 The member 22 is hermetically sealed from the outside. In conjunction with the operation of the push rod 2i, the gas cylinder (fuel tank) 7 successively injects the combustible gas into the combustion chamber through the chaotic injection 埠19, and the chamber button switch 23 (normally open switch) measures the combustion chamber frame. When 15 is at the center of the top dead center and is turned on, the driving circuit of the motor 8 is also turned on to turn the fan 6 into a red fan. In the hermetically sealed combustion chamber, the fan (4) acts together with both fins 16 projecting into the combustion chamber 15a.

The injected combustible gas and air are disturbed and mixed in the combustion chamber 15a. The gas cylinder 7 stores - a liquefied flammable gas in an upshifted state. This liquefied gas evaporates when injected into the combustion chamber 15a. At the top end of the gas cylinder bottle 7, a measuring valve 7a is provided for adjusting the amount of gas injected from there. Therefore, the amount of adjustment of the gas is supplied through the gas injection port 19 . When the user pulls the normally closed trigger switch 12 on the handle U, the trigger switch 12 will be turned off, and after the pusher 21 is pressed against the workpiece 29, the operation of the controller 100 described later will be able to The spark plug 9 is controlled to generate a spark to ignite and combust the mixture of air and fuel. The expanded combustion gas forces the piston 10 downward to impact the nail 24 in the nose. After driving the nail 24, the piston 1G contacts the bumper 2, and the burned gas passes through the exhaust port 3 and escapes from the cylinder 4. Out. As described above, the check valve (not shown) is provided with an exhaust port 3. After the gas escapes from the cylinder 4, the check valve ' is closed and the steam red 4 and the combustion chamber 15a return to atmospheric pressure. Since the burned gas remaining in the cylinder 4 and the combustion chamber 15a after combustion is very hot, the steam red 4 and the inner wall of the combustion chamber frame 15 and the fin 312XP/invention specification (supplement)/96-11/96132686 20 1361744 Sheet 16 and the like can absorb heat of combustion. Therefore, the 'burned gas' will rapidly cool down and reduce its volume, thus creating a thermal vacuum in which the pressure in the combustion chamber 15a will drop below atmospheric pressure, allowing the piston 10 to be pulled back to its original top dead center position. . When the user successively releases the trigger switch 12, the trigger switch 12 is returned.

When the ON state (normally closed state) is reached, and the body of the tool is lifted so that the push rod 21 is separated from the workpiece 29, the pressing force of the spring 26 causes the push rod 21 and the combustion chamber frame 15 to move downward to the beginning shown in FIG. status. At this time, under the control of the controller 100, even if the key switch 23 is turned off, the fan 6 continues to rotate for a prescribed period of time. In the state shown in Fig. 2, the gaps 17 and 18 are formed above and below the combustion chamber frame 15 to release the combustion chamber 15a from its hermetic sealing state. In this state, the fan 6 generates an air flow, which is sucked into the fresh air through the air intake port 28 formed in the top surface of the outer casing 14, and is passed through the exhaust enthalpy formed in the outer casing 14 to cause residual combustion. The % body σ human out 'by this to clear the air in the combustion chamber 15a. Then, the fan 6 stops and returns to its initial resting state. In the preferred embodiment, a normally open switch is used as the push button switch 23, and a normally closed switch is used as the trigger switch 12. Next, the controller 1 〇 使用 using the push button switch 23 having this configuration and the trigger switch 12 will be explained. <Structure of Controller 100> Fig. 3 shows the circuit configuration of the controller 1 〇 。. The controller 1 includes: a low voltage power supply circuit 1 〇 2, a self-holding circuit 1 〇 3, a battery voltage detecting circuit 106, a key switch circuit 丨 05, a trigger switch power 312XP / invention manual ( Supplement) /96-11/96132686 21 丄JOl/44 33^ DC" means that the supply terminal is not connected to the regulator IC1, 4°, and the supply terminal is marked "7.2 VDC" The indication is that the terminal is connected to the 7.2V power supply line from the battery 25 and the battery is supplied with power through the main power supply switch SW1. Second, I keep the electricity, which is composed of a forward feedback circuit. This circuit is connected to the base of the mNP transistor Q3.

The electric 曰 ί and the collector. Connected to - a circuit providing the positive feedback of each other's circuits, Q3 and Q4 (this is a fib * 4- 4db pair; well known in the art), which has phase 5) in two stable states (clear state with (10) State) PNP power: two forces. And ', if the round-trigger signal to increase the transistor Q3 or NPN Thunder γμ +, one phase ~ 〗 The recharge of the base current in the body Q4, while simultaneously applying μμ τ ^ Κ铩 voltage Then, the transistors Q3 and Q4 will change from the qing state to the (10) state through the (four) effect. Conversely, if supplied to the transistor q3盥q4 body (four)...back (four)-like: electricity (four) when the ground falls, then the electron crystal

In the positive direction:: 1 〇, 3 also includes a field effect transistor for applying the -trigger signal to the transistors Q3 and Q4 of the _i path (the following resistors R4 to R9 and capacitor C8) The round center line Di η self-holding effect is used to turn the transistor to the ON state when a stop output signal (high signal) received from the microcomputer 101 Q5 is received in the FET Q5. Effectively switch the transistor 〇n j4 / 〇 FF-like cancer to say, when it comes to (four) the whole test; the history is set to 〇 FF state. More Mingtian from the regulator 1 (: 1 output will be temporarily output from the output terminal Η One contains the day of the micro-electricity 101 _ ^ i 唬 as a trigger signal and 312XP / invention manual bribe y96 11/96132686 23 1361744 FET Q5 is turned on, and will be connected to the transistor (10) on the forward feedback circuit Q4 is switched from the _ state to the (10) state. Therefore, the self-holding circuit 103 can switch the transistor q13 from the 〇N state to the intimidating state to stop the output from the regulator IC1. In this way, the circuit structure can detect An abnormal state, such as when the combustion type power tool 9 is placed on hold For a long time while the main power supply switch SW1 is in the operating state (standby state); when the combustion type power tool 9 is neglected and the *pusher 21 is inadvertently pressed, the button _ 23 is turned on; or when The molten contact causes the push button switch 23 to be continuously turned on, etc., and the circuit structure can enter a low power consumption mode to maintain the output from the adjuster lci in a stopped state to prevent the battery 25 from being unnecessary. Power consumption. In order to return to the operation mode (standby mode), the transistors Q3 and Q4 connected to the forward feedback circuit can be returned to the GN state. In order to return the transistors Q3 and Q4 to OFF, you are strong. , the maker can remove and reconnect the battery 25, or turn off the main power supply switch sn and then turn back on, at this time 'the regulator IC1 starts to supply the specified voltage 3.3V to the microcomputer ι〇ι and the like. The mode 'can return the low voltage power supply circuit 1 〇 2 to its operation mode (standby mode), that is, reset the low voltage power supply circuit 102. Heavy &amp; IC IC2 is an integrated body The circuit device, when the battery 25 is inserted and the main power supply switch sn is turned on, or when the output voltage from the adjustment If IC1 is reset within a prescribed voltage range, the weight 5 is transmitted to the microcomputer 1 〇1 The reset terminal 6 ° battery voltage detecting circuit 106 includes: FETs Q1 and Q2; resistor R1 312XP / invention manual (supplement) / 96-11/96132686 24 1361744 to ^^ and ^: and a capacitor ^ from the battery The voltage supplied by the carrier is divided by the resistors H R14 and R15, and is input to the microcomputer. · HH 'Battery power (4) Measuring circuit 1G6 is also provided - electricity (four) measuring stop power &quot; road 1〇6a, is The FETs Q1 and Q2 and the resistors R1 to R3 are formed. - When the self-holding circuit 1〇3 and the low-voltage power supply circuit 102 enter the low power consumption mode, the FETs Q1 and Q2 are turned off, and the power output from the regulator 停止 is stopped, thereby interrupting the circuit for detecting the battery voltage to prevent being The separate resistors R14 and R15 generate unnecessary power consumption. The push button switch 105 includes a push button switch 23 having a normally open mechanical contact, a resistor and a rii, a diode di and a) 2, and a capacitor C7. When the combustion type power tool 90 is pressed against a workpiece 29 such as a piece of wood, the push button switch 23 is turned on, so that a low signal is transmitted to the terminal 20 of the microcomputer. Due to the mechanical structure of the combustion type power tool 90, the push button switch 23 and the trigger switch 12 are positioned to be separated from the circuit board of the controller 1 and connected to the circuit board via a cable (not shown). However, in some cases, the cable can absorb the impurity §fL generated during ignition or the like, thereby inducing a voltage that can make the ground side positive. Therefore, by providing the diodes D1 and D2 in the ground circuit, the induced voltage passes through the diodes D1 and D2', thereby preventing an excessive voltage from being supplied to the microcomputer 101. In the preferred embodiment, the push button switch 23 is constructed of a normally open switch having mechanical contacts. • The trigger switch circuit 1 includes a trigger switch 12 with mechanical contacts, a transistor Q16' resistors R161, R162, R12, R13 and R43, diodes D4 and D5, and a capacitor C6. According to the invention, the trigger switch 12 312xp / invention specification (supplement) / 96-11 / 96132686 25 1361744 container C5 is charged. More specifically, when the normally closed trigger switch i2 is operated and enters the intimidation state, the inverting transistor Q16 outputs a (10) signal. • This ON彳5 will be transmitted to the charging circuit ^ along two paths. On the first path, the collector side A of the transistor Q16 transmits this signal through the resistor R121 to the base of the transistor q12, and conducts the crystal qi2. Therefore, 仏唬 is transmitted to the collector of the transistor q6. When the trigger opening 12 is operated and turned off, the transistor Q16 simultaneously inputs an on signal to the microcomputer j 〇!, the winter 鳊 19 as the second path. Therefore, the microcomputer 1 〇 1 intermittently outputs a low signal from the 钿11. This signal is input to the base of the transistor Q6 in the charging circuit process 7, whereby the transistor Q6 is turned on and off. Due to the signals on the two routes, the FET q? is repeatedly turned on and off, thereby generating a high voltage on the second side of the transformer T1 for charging the ignition capacitor C5 through the diode D6. Although the trigger switch 12 is not operated, that is, when the trigger switch 丨2 is ON, 'even if the abnormal power % voltage generated due to noise or the like is input to the terminal 19 of the microcomputer 101, the microcomputer 1〇 1 outputs a signal for charging the ignition capacitor C5, and the charging circuit ι7 does not conduct the crystal Q12 to start charging the ignition capacitor C5. The ignition circuit 108 includes: a spark plug 9, a thyristor SCR1, a transistor Q8, a pole D7, a capacitor C4, and resistors R81, R82, R21; the microcomputer 101 generates a low signal from the terminal 10 as an ignition. And conduct the crystal Q8. Thus, this signal is transmitted to the idle electrode of the thyristor SCR1 to turn on the thyristor SCR1. When the gate fluid SCR1 is turned on, the energy stored in the ignition capacitor is released. From point 312XP/invention specification (supplement)/96-11/96132686 27 1361744 The energy released by the thermal capacitor C5 is boosted by the transformer T2 to approximately i5 kV to generate a spark by the spark plug 9. After the ignition circuit is activated, the microcomputer 101 acts to input an ON signal into the gate of the thyristor k·SCR1 for an interval of, for example, 1 〇 msec. The motor drive circuit 109 is composed of NPN transistors Q9 and Q10, PNP electromorph Q11' resistors R23 to R26, diodes D10 to D13, and a capacitor Cl1. When the key switch 23 is operated to change from 〇FF to 〇N, the microcomputer 101 outputs a low signal from the terminal 丨2, turns off the NpN power, the crystal Q9, and turns on the NPN transistor Qi 〇 and the PNP transistor Q11 so as to be 7. A battery voltage of 2V is applied to the drive circuit section of the motor 8. Therefore, when the combustion type power tool 90 is pressed against the workpiece, the fan 6 will rotate to turn on the push button switch 23. The display circuit 110 includes a light emitting diode (LED) and resistors R16 and R17. When the battery 25 is installed in the combustion type power tool 9 且 and the main power supply switch SW1 is turned on, the microcomputer % generates a low signal in the middle of the terminal 丨 6 to cause the LED to start emitting green light to indicate This combustion type power tool 90 is ready for use. When the combustion type power tool 90 is depressed against the workpiece 29, the motor 8 is driven and the microcomputer 101 outputs a low signal from the terminal 16 to turn on the green light in the LEI), indicating that the nail can be discharged. Moreover, although the controller 1 is not in the low power consumption mode, when the voltage in the battery 25 does not reach: to the reference voltage (for example, 7.2 V), the controller 1 outputs one from the terminal 15. Low nickname. Therefore, the LED 11 emits red light to tell the user of the combustion type power tool 90 that the battery 25 must be charged. 312XP/Invention Manual (Supplement)/96-11/96132686 28 1361744=When the combustion type power tool 90 is pressed against the workpiece 29, the push cup 21 can be moved upward, so that the gas cylinder 7 will The flammable gas is entered into the combustion chamber 15a, and the push switch 23 is in the (10) state. As described above, a signal is applied to the control terminal 2 of the microcomputer 101. The microcomputer 101 rotates a drive signal from the output terminal 12 to the motor drive circuit (10), and the drive motor 8 starts to rotate the fan 6 to impart and mix the combustible gas and air in the combustion chamber bore. When the g user subsequently operates the trigger switch 12 and the trigger 'switch 12 changes from ON to 0FF, the microcomputer 1〇1 controls the charging circuit 1〇7 and the ignition circuit 108 to generate a spark in the spark plug 9 to ignite. This mixture of air fuels. As a result, the driver blade 1A drives the nail 24 within the workpiece 29. If the combustion type power tool 90 is idle for a predetermined period of time (for example, ten is Cui Li), after the push button switch 23 is turned on, the trigger switch 12 is not operated during this period, and the self-holding circuit 103 enters the above low power. $consumption mode. Since the combustion type power tool 9 is not operable at this time, as described above, it is necessary to return the combustion type power tool 9 to the operation mode to continuously operate the rotation of the fan 6 in accordance with the push button switch 23 and the trigger switch 12, and the ignition capacitor C5. Charging, sparking of the spark plug 9, etc., regardless of the 0N/0FF state of other switches. Therefore, by pressing the combustion type power tool 90 against the workpiece 29, the combustible gas can be injected into the combustion to 15a' if the flammable gas is not due to the ambient temperature or pressure in the gas cylinder. Fully evaporating or agitating, by pulling the trigger switch 12 multiple times while keeping the combustion-type power tool 9〇 pressed against the 312XP/invention manual (supplement 29 1361744 workpiece 29, the flammable gas can still be Ignition. At the initial state of operation of the combustion type power tool 90 when the battery 25 is inserted and the main power supply switch SW1 is turned on, the microcomputer 1 is reset. Although the key switch 23 is continuously turned off, the microcomputer is turned on. 1. Detecting whether the combustion type power tool 90 is being used in order to prevent the battery 25 from being depleted when the combustion type power tool 90 is placed in the operation mode for a long time, for example, if the button switch 23 is in the 〇FF state Ten minutes, the microcomputer 101 will transmit a trigger signal from the terminal 24 to the self-holding circuit 103 to place the low-voltage power supply circuit 1〇2. Power consumption mode. As described above, subjected to a great impact of the trigger switch during the driving operation of the combustion type power tool 9〇 12 in the present invention is normally closed by a mechanical switch

The composition of the customs. Therefore, when the trigger switch 12 is operated, the mechanical contact in the trigger switch U is turned off (0FF), and when the switch is subjected to an impact during the nail driving operation, the mechanical contacts are not in contact, thereby preventing the switch Mechanical wear. However, since the push switch 23 and the trigger switch 12 are connected in series in the present invention, the push switch 23 and the trigger switch 12 are connected to a low voltage power supply (3.3 V) through the resistor R10. Moreover, the power supply voltage of the 3 Μ is connected to the key switch through the resistor R43. - The connection point with the trigger switch 12. Such a configuration when the push switch 23 and the touch switch 12 are not operated can enable the current by the resistor R43 to flow into the trigger switch 12, thereby suppressing current consumption during non-operation. However, when the push button switch 23α is turned on, the current adjusted by the resistor R10 312XIV (the y96_11/96132686 30 1361744 can flow to the push button switch 23, and the electric current/force L 流 flowing to the trigger switch 丨2 is The sum of the current limited by the resistor R43 and the current limited by the resistor ri 。. According to the above operation, when the normally-on type key switch 23 is turned on, the micro-power month a 101 receives a low signal at the terminal 20, The motor drive circuit 1 〇9 is controlled to drive the motor 8. Then, when the normally closed type trigger switch 丨2 is operated, the trigger switch 12 is turned off, thereby interrupting the conduction in the trigger switch 12.

This current flowing through the resistor R43 can flow to the base of the transistor 6, and the capacitor Q16 is turned on and the microcomputer can receive the low number 5 at the terminal 19 to control the ignition circuit 1 〇 8 in the spark plug 9 A spark is generated inside. The configuration of the above preferred embodiment can limit the current flowing into the trigger switch 12 when the button switch 23 is not operated to a required minimum amount of minute current 'and can provide a current when the button switch 23 is operated. The current is sufficient to prevent the formation of an oxide film that causes contact failure at the junction of the switch. Moreover, the power consumption is not unnecessarily increased, and this configuration allows a part of the current (armature current) in the motor 8 to flow to the trigger switch 12 to provide a current sufficient to prevent oxidation. Specifically, the motor current flows from the negative terminal of the motor 8 through the diode di 3 to the contact between the push switch 23 and the trigger switch 12. This diode D12 is inserted on the ground side of a bypass, where the motor current is supplied to the junction of the trigger switch 12. This configuration prevents oxidation by causing motor current to flow to the junction ' of the trigger switch 丨2. In the above preferred embodiment, the button is opened 312XP / invention manual (supplement) / 96-11 / 96132686 31 1361744 2 off 3 = two, the trigger switch 12 is connected, but the ground side of the button switch 23 can be combined with the trigger switch 12 Separate and ground directly. In the on &gt; key switch 2 3 should be composed of a normally closed switch with a # ^ μ pull out # m finer than eight hundred mechanical contacts, like the trigger switch 12, and similar to the transistor Q16 and resistor Trigger of R1H and R162 - ^ ^ ^ ^ ^ j The reverse phase benefit circuit of the circuit 12 is applied to the key switch 23. <Embodiment of Electronic Power Tool 70>

n ^ . ^ ^ The example of "there is a push button switch and a trigger sweat 1 power tool (wireless nail driver) 7", and Fig. 5 is a block diagram of the controller 81 used in the electronic power tool 70. In the preferred embodiment, the electronic power tool 7G has a - (four) - trigger switch 75' which is comprised of a normally closed switch having mechanical contacts, and thus changes from an 0N state to a 〇FF1 state when operating. As with the embodiment of the above-described combustion type power tool, the structure of such an electronic power tool can prevent the friction of the mechanical joint caused by the chatter.

As shown in Fig. 4, the 'electronic type power tool 7' is composed of a main casing 71a having a nail striking portion 71c at the front end, a nail striking portion 71c provided on the main casing, and continuously supplying the nail to the nail striking portion 71c. a handle 72, a handle housing 7ib extending vertically downward from the main housing 71a, a trigger switch 75 provided on the branch portion of the handle housing 71b for performing a nail driving operation, and a bottom end connected to the handle housing 71b and A battery pack 77 composed of a lithium ion battery or another auxiliary battery is configured. Although not shown in the figure, the magazine 72 is provided with a plurality of linked (batch) nails from a 3I2XP/invention specification (supplement)/96 by a spring (not shown). -11/96132686 32 1361744 The bottom of the Bullet® 72 is pushed, causing the nail 72a to hit the shirt 7 in succession! The crucible 71c is driven through a discharge outlet 71d or a nail striking portion 71c. The actuator 73 is provided to the main casing 71aβ for applying a nail 72a that collides with the nail striking portion 71c to drive the nail 72a. Two 73 includes a function for transmitting the impact force to the head of the needle

St, and a tooth that hangs with the rotating small life wheel 80

The rack 73b of the 'moving β 73 and the small two-80 holding the rack 73b constitute a driver feeding mechanism 73. 'Used to apply the rotational driving force of the small tooth ' to the driver 73 as a linear driving force〇

The Dct housing also houses: a motor 96 (reference ® 5), such as a: and a motor, which is driven by the power source from the battery pack 77 and is: a drive source; a motor gear 78 is fixed to the motor % of the rotary &amp; wheel 79 has a tooth that is combined with the motor gear 78 (four)

The pinion gears (10) are rotated coaxially with each other, but both are switched to be engaged with the pinion gear 8 between a merging state and a disengaged state. The axis of rotation; the table: the surface of the outer surface of the outer surface of the shaft is 79. In the separated state, the inner diameter of the flywheel Μ ^ ^ m, 丨 does not contact the axis of rotation of the pinion 80 ^ Surface. The consumption is not shown in _, but this clutch is controlled by the reciprocating action of the solenoid 93 (refer to Fig. 5). The slewing wheel 79 is sprayed with the π phase of the motor gear π phase, and stores the kinetic energy of the rotational motion from the motor 96. The drive rotational drive force is applied to the driver blades. The structure 73c rotates the flywheel 79 as a linear driving force, using 312XP/invention specification (supplement)/96·ιι/96132686 ^ 丄JO丄/44

Second, the leaves... move in the nail impact &amp; neutron 72a. J: The same is true for the burning type power tool. When the button switch is pressed to close the button switch 8&quot;, the electronic type power tool is also Γ5=status (standby state). When the user then operates the trigger switch to trigger the on_75, a transistor-like reference is

Supply current to the solenoid 93. Therefore, the clutch mechanism is constructed: the solenoid 93 transmits the rotational force from the motor 96 to the pinion gear 80 that constitutes the driver feed mechanism 73c when the flywheel core accumulates (four) energy. The sprocket will convert the rotational motion of the wheel 80 into a linear motion to drive the driver blade 73a fixed to the burglary 73 into the head of the nail 72a. After the moving/blade 73a hits the nail 72a, the electricity flowing to the solenoid is turned off, so that the clutch mechanism returns to the separated state. Further, a drive feed spring 74 composed of, for example, a solid-force 1 magazine is connected to the end of the drive f 73. The elastic force of the drive feed spring 74 enables the drive &amp; feed mechanism 73c (the rack shift and the pinion 8 ()) to return from the position after the impact thereof to the initial position before the impact. The controller 81, which is placed in the main peripheral device 71a, can also control the entire fall of the electronic power tool 70 according to the operation of the push switch 85 and the switch 75. <Structure of the controller 81> The following will refer to the figure. 5 illustrates the controller 81. As shown in FIG. 5, the controller 81 includes a microcomputer (control circuit) 86, 312XP/invention specification (supplement)/96·ι 1/96132686 34 1361744, a low voltage supply circuit 84, a self-holding circuit 87, and a motor. A drive circuit 94, a motor drive transistor 95, a solenoid drive circuit 91, a solenoid drive transistor 92, a push button switch 82, and a trigger switch 75. As in the above-described first embodiment, the battery pack 77 is the power source of the controller 81, and is composed of, for example, a 7.2V lithium ion auxiliary battery (battery pack). The battery pack 77 supplies power to the low voltage supply circuit 84, the motor drive transistor 95, and the solenoid drive transistor 92 through the main power supply switch 88. The low voltage supply circuit 84 has a function for lowering the power supply to, for example, 3. ,, and a function corresponding to the input signal of the control input terminal 84a to select whether to output a prescribed low voltage or to stop outputting the low voltage. A motor detecting circuit 89 is provided for detecting the timing of the rotational force required by the motor 96 to reach the driving pin, and inputting the detecting signal into the microcomputer 86. In the present invention, the push switch 82 and the trigger switch 75 are constituted by the above-described normally closed switch having a mechanical contact, and are switched from the ON state to the 〇FF state during operation. The first and second pre-measurement circuits 82a having the inverters for inverting the phase are respectively provided for the button switch and the touch switch 75' and 'when the individual switches are operated, the system is configured Second, an 0N level (ground level) signal is input to the microcomputer 86. • When the button switch 82 and the trigger switch 75 are operated (ie, turned off), the microcomputer 86 is controlled according to the rotation state of the motor % and the debt measurement signal generated by the first detecting circuit 82a and the second detecting circuit 75a. The motor drive circuit 94 of the motor 96 and the motor drive transistor 95 and the solenoid drive circuit 91 of the solenoid 93 and the solenoid drive transistor 92. When the motor (10) 312XP / invention manual (supplement) / 96 · 11 / 96 ΐ 32686 35 1361744

Used to determine the rotation state of the motor 96 (such as when rotating)

The data input by the motor 96; and a scoop control program; a work area for random access memory a and temporarily storing slaves and a timer (TIM) 86d including a reference clock signal generator. The microcomputer 86 supplies a motor drive signal to the motor drive circuit 94 for controlling the base current of the motor drive transistor 95 (for example, a PNP transistor) to apply the voltage of the battery pack 77 to the motor 96, and A solenoid drive signal is also supplied to the solenoid drive circuit 91 for controlling the drive time (0N time) of the solenoid 93. Motor drive circuit 94 drives motor drive transistor 95 for switching motor drive transistor 95 to ON or OFF&apos; to control whether a drive current is supplied to motor %. The solenoid drive circuit 91 drives the solenoid drive transistor 92 (e.g., .PNP transistor) to control whether a drive current is supplied to the solenoid. As with the preferred embodiment of the above-described combustion type power tool, the self-holding circuit 87 can be obtained by connecting the collector circuits of the PNP transistor and the NPN transistor to the base feedback circuits of each other. This self-holding circuit 87 has a function of replacing the microcomputer 86, the solenoid drive circuit 91, and the motor drive 312XP/invention specification (supplement)/96-11/96132686 36 1361744 = road 94* t knife into a low power consumption mode. More specifically, as in the above-described first example, if the electronic type has not been operated for a predetermined period of time after the button switch 82 is turned off, the microcomputer 86 Ζ-stop output signal is transmitted to the self-holding circuit 87 as a trigger signal. (Example: (10) state) 'Use to stop ^: body ^ ^ first steady state

Keeping at low power consumption ^ I keep circuit 87 to work with it and 7 (1 栌X, type hunting to prevent 畲 not using electronic power 〆, 70 8 defensive unnecessary lei 6, red, „ rate The user who wants to leave the low-powered ^_-style phantom money with the electronic power tool Π = Π. Source return supply / - off and then turn on, and the electronic, force 70 return to the operating mode (standby Mode). With this structure, when the controller presses (4) off 82 to close the button switch 82, the electronic power / '

Life mode). If the user enters the operating mode (waiting for the use of the trigger switch 75, the line: drives the transistor 92 and supplies current to the solenoid 93. 1:= the solenoid 93 of the clutch mechanism will be occupied by the inside θ &amp; 'The kicking force of the Yun 96 is on the flywheel 79. The second gear is set to the machine u UW wheel δ 〇. When the pinion gear 80 rotates, the rack gear converts the rotation motion of the pinion gear 80 into ^ 80 phase sound. The driving number fixed to the driver 73 is linearly operated for use in the head. When: motion = ^, the button switch 82 and the trigger switch 75 can both bear the money 72a, both the 82 and the trigger switch 75 At the same time, but the key switch is sorrowful to prevent the wear of the mechanical joints in the opening of the 3i2XP / invention manual (supplement) / 96-11/96132686 37 1361744. *Although β has referred to the above preferred embodiment The present invention is described in detail, but it will be apparent to those skilled in the art that many modifications and changes can be made without departing from the spirit and scope of the invention. The scope of the invention should be defined by the scope of the following patent application. <Industrial Applicability> The present invention can be applied to, for example, a power worker that drives a fastener in a workpiece. The power Guard to which the present invention is applied should include - for detecting whether the tool is pressed against the workpiece a push button switch, and a trigger switch for ordering to drive the fastener in the workpiece. The lower 7 drive (simplified description) ® 1 S control block used in the power tool according to an embodiment of the present invention Figure 2 is a cross-sectional view of a combustion type power tool in accordance with a preferred embodiment of the present invention. Fig. 3 is a block diagram of a controller used in the combustion type power tool shown in Fig. 2. A cross-sectional view of an electronic power tool according to another embodiment of the invention. Fig. 5 is a block diagram of a controller used in the electronic power tool shown in Fig. 4. [Key element symbol description] 1 Nose 312ΧΡ /Invention manual (supplement)/96·11/96132686 38 1361744 2 6 7 7a

10 10a 11 12 13 14

15a 16 17 18 19 20 20a 21 Buffer Exhaust Cylinder Temperature Sensor Fan Gas Cylinder Measurement Valve Fan Motor Mars Plug Piston Driver Blade Handle Trigger Switch (Normally Closed Switch) Magazine Shell Combustion Chamber Frame Combustor Fin Clearance Clearance Gas injection head cover hood push rod 312XP / invention manual (supplement) / 96-11/96132686 39 1361744 22 sealing member 23 push button switch (normally open switch) 24 nail 25 battery 26 spring 28 air inlet 29 workpiece 60 power tool

61 drive circuit 62 control circuit (microcomputer) 63 low voltage power supply circuit 64 self-hold circuit 65 key switch 65a first detection switch 66 trigger switch 66a second detection switch 67 main power supply switch 68 display circuit 69 battery 70 electronic type Power tool (wireless nail driver) 71a Main housing 71b Handle housing 71c Nap impact portion 71 d Discharge outlet 312XP / invention manual (supplement) / 96-11/96132686 40 1361744 72 magazine 72a nail. 73 driver 73a driver blade 73b Rack 73c Drive feed mechanism 74 Drive feed spring 75 Trigger switch (normally closed switch) • 75a f 2 detection circuit 77 Battery pack 78 Motor gear 79 Flywheel 80 Pinion 81 Controller 82

Key switch (normally closed switch) First detection circuit Low voltage supply circuit Microcomputer 86a Central processing unit (CPU) 86b Read only memory (ROM) '86c Random access memory (RAM) -86d Timer (TIM) 87 Self-holding circuit 89 Motor detection circuit 312XP / invention manual (supplement) / 96-11/96132686 41 1361744 90 combustion type power tool (nail driver) 91 solenoid drive circuit 92 solenoid drive transistor 93 solenoid 94 Motor Drive Circuit 95 Motor Drive Transistor 96 Motor 100 Controller

101 microcomputer (operation control circuit) 102 low voltage power supply circuit (regulator) 103 self-hold circuit 104 trigger switch circuit 105 key switch circuit 106 battery voltage detection circuit 106a voltage detection stop circuit 107 charging circuit 108 ignition circuit 109 motor drive Circuit 110 Display Circuit 111 Crystal Oscillator 312XP / Invention Manual (supplement) / 96-11/96132686 42

Claims (1)

1361744 NOV 1 5 20ίί 瘈 瘈 十 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 'Starting when the operation of the sniper fastener is ready to be executed; and triggering a switch to be activated by the user when the operation of the slamming fastener is triggered, wherein at least one of the push button switch and the trigger switch is a climber Normally closed switch. 2. The power tool of claim 1, further comprising: a first detecting circuit connected to the button switch, and detecting that the button switch is activated, the first detecting circuit outputting a button indicating a first detection signal that is activated by the switch; a second detection circuit is connected to the trigger switch, and detects that the trigger switch is activated, and the second detection circuit outputs a signal indicating that the trigger switch is activated a second detection signal; a control circuit is connected to the first detection circuit and the second detection circuit, and commands the driving circuit to drive corresponding to the first detection signal and the second detection signal The power generation mechanism. 3. The power tool of claim 2, wherein when the button switch is formed by a normally closed switch, the first detecting circuit includes an inverter circuit for inverting a signal from the button switch. And applying an inverted signal to the control circuit as the first detection signal. 4. For example, the power tool of the second application of the patent scope, wherein when the trigger is open 96132686 43 U61744 1〇4 15 Amendment 牟月曰补无: When it is composed of a normally closed switch, the second detection circuit includes an inversion Device = Used to invert - the signal from the trigger switch and apply - the inverted signal J. The control circuit is used as the second detection signal. 5. The power tool of item i of the patent scope, wherein the push button switch is connected in series with the trigger open relationship. 6. For example, in the power tool of claim i, wherein the button switch /, the trigger switch is composed of a normally open switch, and the button switch is The remaining one of the trigger switches is composed of a normally closed switch, and the push button switch is connected in series with the trigger open relationship. 7. The power tool of claim 6, wherein the current flowing through the normally closed switch when the normally open switch is ON is greater than the current flowing into the normally closed switch when the normally open switch is OFF. 8. A power tool comprising: an outer casing; a cylinder disposed on the inner side of the outer casing; a pendulum sleeve disposed on one end of the outer casing; a piston disposed in the cylinder and reciprocable in the cylinder a driver blade fixed to the piston for driving the fastener in a workpiece; a push rod 'extending from the other end of the outer casing and capable of moving when pushed against the workpiece; a combustion chamber frame disposed at Inside the housing, and movable along with the action of the push rod, the combustion chamber frame defining a combustion chamber together with the cylinder, the piston and the head sleeve; 96132686 44 1361744 &quot;ϊνϊρ supplementing a push switch, together with the mast A &quot;'^^ move. - The Mars plug' is set to face the interior of the combustion chamber; and the = switch, activated by the user, to trigger the ignition of the spark plug: Γ. The at least one of the push button switch and the trigger switch is a normally closed switch 9. The power tool of the eighth aspect of the patent application, further comprising a - detecting circuit is connected to the push button switch, and detecting the The button switch is activated, the first detecting circuit output is a first detecting signal indicating that the button switch is activated, and a second detecting circuit is connected to the trigger switch, and detecting that the trigger switch is activated, The second detecting circuit outputs a second detecting signal indicating the activation of the trigger switch; and a control circuit is connected to the first detecting circuit and the second detecting circuit, and corresponding to the first The detection signal and the second detection signal command the spark plug to ignite. 10. The power tool of claim 9, wherein when the button switch is constituted by a normally closed switch, the first detecting circuit includes an inverter circuit for inverting a signal from the button switch. And applying an inverted signal to the control circuit as the first detection signal. 11. The power tool of claim 9, wherein when the trigger switch is formed by a normally closed switch, the second detecting circuit includes an inverter circuit for inverting a signal from the trigger switch. And applying an inverted signal to the control circuit as the second detection signal. 96132686 45 Supplement 1361744 12. The power tool of claim 8 wherein one of the pressing and triggering switches is constituted by a normally open switch field crane switch, and the button switch, the remaining one of the touch switches It consists of a normally closed switch and is connected in series with the trigger open relationship. "Key switch 13" The power tool of claim 12, wherein the current flowing through the normally closed switch when the normally open is (10) is greater than the current flowing through the normally open switch: OFF 訏 into the normally closed switch. 14. A power tool comprising: a motor for rotating a flywheel; - a driver blade for driving a fastener in the workpiece, the driver blade moving in a predetermined direction; a 茱 ^ 进 feeding mechanism The rotational force of the flywheel is converted into a force for moving the drive vane in a predetermined direction; medium: the power transmitter 'transmits the rotational force of the flywheel to the blade feed mechanism or a push button switch' when the impact fastener is operated When the execution is started; the trigger switch 'starts when the operation of the impact fastener is triggered, and the control circuit' controls the motor and the power transmitter according to the activation of the button switch and the trigger switch; At least the switch and the trigger switch are formed by a normally closed switch. I5. The power tool of claim 14, wherein one of the push button switch and the trigger switch is constituted by a normally open switch, and the button switch 96132686 46 1361744 and the remaining one of the trigger switch are constituted by a normally closed switch, And the button switch is connected in series with the trigger on relationship. 16. The power tool of claim 15, wherein the current flowing through the normally closed switch when the normally open switch is ON is greater than the current flowing into the normally closed switch when the normally open switch is OFF. 96132686 47