Electric drive tool

The electric drive tool of the invention is configured such that a lock lever is provided to reliably prevent an erroneous operation of a trigger and an operating mode can be switched by changing an operational sequence of this lock lever and a contact trip.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a drive tool for driving driven members, such as nails, into a driven material using an electric motor as a drive source.

2. Description of the Related Art

For example, a nail driving machine generally uses compressed air as a driving source, and a large striking power can be obtained by reciprocating a piston with the compressed air. In contrast, a tool has been proposed which strikes driven members, such as nails, by reciprocating a striking driver (a striking rod) with an electric motor as a driving source. Since driving the electric motor as the driving source with a direct current power source (a battery) makes connection of an air hose and a device such as a compressor in the case of an air system to become unnecessary, usability and handling property of the driven tools can be improved.

This electric drive tool has a basic configuration in which a drive wheel is rotated with the electric motor as the driving source, and a driver supporting base which supports the driver is strongly pressed against a peripheral surface of the drive wheel, so that a linear movement (a striking operation) in the direction of driving the driver is obtained.

As a technology relating to the electric drive tool, the one disclosed, for example, in U.S. Pat. No. 7,137,541 is publicly known in the related art. The technology disclosed in this Patent Document is configured to achieve a driving operation by getting the drive wheel to rotate in advance in a standby state by activating the electric motor at a moment when one of a first operation to press a contact trip against a driven material to move the same relatively upward and a second operation to pull a trigger-type switch lever (a trigger) with a finger tip is performed, and then by pressing the driver supporting base against the drive wheel at the timing when the other one is performed. According to this technology, activating the electric motor and getting the drive wheel to rotate in advance in a standby state by performing one of the first and the second operations causes a quick driving operation to be achieved at the timing when the other operation is performed.

However, according to the technology in the related art, since the configuration is such that the driving operation is performed by the pull operation of the trigger by the second operation in a state in which the contact trip is moved upward by the first operation, and the electric motor is started and the drive wheel starts to rotate in a standby state by the second operation before performing the first operation, it is preferable to include a third operation as a condition of starting the driving operation in view of prevention of an erroneous operation of the drive tool.

Further, in this kind of drive tool, a driving operation is performed one time when the first operation and the second operation are performed, and for performing a second driving operation and its subsequent driving operations there has been incorporated a continuous shot mode, in which continuous driving operations are performed by once performing an off-operation of the contact trip and by again performing an on-operation (first operation) while the trigger (second operation) is being pulled, and a single shot mode, in which a second driving operation cannot be performed unless off-operations of both the first operation and the second operation are once performed to reset to an initial state every time after the driving operation. Previously, one having a special switchable lever has been provided in order to switch between these operating modes, but a prompt mode switching cannot be performed owing to a troublesome switching operation.

Therefore, it is an object of the present invention to provide a drive tool that can reliably prevent an erroneous operation of the drive tool by allowing a driving operation only when a third operation is performed in addition to the first and second operation and that can realize a mode switching operation without troublesome operations of a lever as conventionally required.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, it is necessary to release a locking mechanism (a third operation) in order to pull the trigger. Also, when performing the second operation before the first operation, releasing the locking mechanism is required by the third operation in advance.

Therefore, it is necessary to release the locking mechanism (the third operation) in advance in order to pull the trigger (the second operation), whereby it is ensured that an unintended operation of the drive tool can be prevented by preventing a mishandling of the trigger.

Further, according to the first aspect of the invention, an unintended operation of the trigger can be prevented and the locking mechanism can be effectively utilized to switch a operating mode, because an operating mode can be switched based on an operational sequence of the two operations, a contact trip operation and an unlock operation of the locking mechanism, not based on the conventional operation of the switching lever. According to this configuration, a driving is performed in a single shot mode when the contact trip is operated first and then an unlock operation of the locking mechanism is performed, and after that a pull operation of the trigger is performed. A driving is performed in a continuous mode when an unlock operation of the locking mechanism is performed and next the contact trip is operated, and after that a pull operation of the trigger is performed.

In abolishing a conventional switching lever, it may be possible that an operating mode could be switched based on an operational sequence of the contact trip and the trigger, but according to the drive tool as described in claim1, prevention of an erroneous operation of the trigger and improvement in switching operability of operating modes can be both satisfied by configuring such that a locking mechanism is newly provided to prevent an erroneous operation of the trigger and an operating mode can be switched based on an operational sequence of an unlock operation of this locking mechanism and the contact trip.

According to a second aspect of the invention, an operating mode can be switched based on an operational sequence of the three operations, the contact trip, the trigger, and the locking mechanism. Therefore, the tool is configured such that an erroneous operation of the trigger can be prevented and the locking mechanism is effectively utilized to switch an operating mode.

According to a third aspect of the invention, without resetting all operations of the contact trip, trigger, and the locking mechanism, an operating mode can be switched by maintaining a state of either one operation and changing the other operational sequences.

According to another aspect of the invention, an unintended switching of operating modes during an operation can be prevented because an active operating mode is maintained unless at least an on-operation of the contact trip and a release operation of the locking mechanism are reset to return to an initial state. In this case, when the two operations, the first operation and the third operation, are reset, or when the first operation to the third operation are all reset to return to an initial state, an operating mode can be set again by a following operational sequence.

According to another aspect of the invention, a switching operation between a continuous mode and a single shot mode, which have been conventionally used in general, can be performed.

According to another aspect of the invention, an unintended driving operation can be prevented since an unintended operation can be controlled as an error mode.

DETAILED DESCRIPTION OF THE INVENTION

Next, an embodiment of the present invention will be described with reference toFIGS. 1 to 17.FIG. 1andFIG. 2show a drive tool1according to this embodiment. The drive tool1includes a body portion2, a handle portion3, and a magazine5.

The body portion2has a configuration including a driving mechanism10using an electric motor11as a driving source provided in the interior of a body housing7of a substantially cylindrical resin-made two-piece structure. One nail n is struck and driven into a driven material W by the driving mechanism10. Detailed description of the driving mechanism10will be given later.

The handle portion3is provided integrally in a state of protruding laterally from a lateral part of the body portion2. The handle portion3has a two-piece structure formed integrally with a lateral part of the body housing7. The handle portion3includes a trigger4(a switch lever of a trigger type) and a lock lever30which are arranged at a base portion thereof. A rechargeable type battery pack6is mounted at a distal end of the handle portion3. The electric motor11is started by the battery pack6as a power source.

The magazine5having a number of driven members (in this example, the nails n-n are exemplified) loaded therein is provided so as to extend between a distal end of the body portion2and the distal end of the handle portion3. A number of relatively thin nails n-n, so-called finishing nails, are loaded in parallel to each other in the exemplified magazine5. This magazine5is provided with a pushing plate5awhich is moved in a feeding direction (toward the left inFIG. 1) in conjunction with the driving operation of the body portion2. The nail n is fed one by one to a driving position of the body portion2by the pushing plate5a.

FIG. 1shows a state in which a distal end portion of the body portion2is directed toward the driven material W. Therefore, inFIG. 1, the downward direction corresponds to the driving direction of the nail n. In the description given below, the direction along the driving direction is referred to as the vertical direction unless otherwise specified.

The electric motor11as the driving source of the driving mechanism10is housed within a rear portion (an upper section inFIG. 1) of the body housing7. A driving pulley12is attached to an output shaft of the electric motor11. A driven pulley13is arranged substantially centrally in the body housing7in the longitudinal direction (the length direction of the tool, the vertical direction inFIG. 1) so as to correspond to the driving pulley12. As shown inFIG. 3, the driven pulley13is attached to an end portion of a drive shaft14rotatably supported by the body housing7via bearings14a,14b. A drive wheel15is attached to the drive shaft14in addition to the driven pulley13. The drive wheel15and the driven pulley13rotate coaxially and together via the drive shaft14.

A driving belt16is put to extend between the driving pulley12and the driven pulley13. The driven pulley13is rotated by the driving belt16when the driving pulley12is rotated by the activation of the electric motor11, and hence the drive wheel15is rotated together via the drive shaft14.

In the case of this example, the drive wheel15has a double structure including an inner wheel15aand an outer wheel15b. The outer wheel15bis mounted on the outer peripheral side of the inner wheel15aconcentrically in a state of no play. The outer wheel15bis mounted to the inner wheel15aso as to be capable of relative displacement in the rotational direction. However, members for transmitting a rotational force are inserted between the inner wheel15aand the outer wheel15b, so that a rotational force of the electric motor11is transmitted from the inner wheel15ato the outer wheel15b. As members for transmitting the rotational force, fine and hard granular substances such as alumina powder or ceramics powder are used. According to the drive wheel15having the double structure as described above, an excessive rotational force at the time of starting the driving operation etc. can be absorbed by slippage between the wheels15a,15b(the relative rotation), so that the durability of the drive tool1can be improved. On the other hand, it is ensured that an adequate rotational force is transmitted from the inner wheel15ato the outer wheel15bvia the members for transmitting the rotational force.

Flange portions15c,15dare formed so as to protrude from both end portions of the outer wheel15bin the width direction. Between the both flange portions15c,15d, a rubber ring17having a high coefficient of friction is attached on the entire circumference of an outer peripheral surface of the outer wheel15b.

Next, as shown inFIG. 1, at substantially the center of the body housing7, a driver supporting base20is provided so as to be movable along the driving direction by way of a slide supporting mechanism that is not shown. A driver21is attached to a distal end (in the lower side ofFIG. 1) of the driver supporting base20. The driver21is elongated toward a distal end (downward inFIG. 1).

The driver supporting base20is arranged to be movable in the direction of the tangent to the above-described drive wheel15, and a lateral side portion (a right1side part inFIG. 1) thereof is positioned between the both flange portions15c,15dof the drive wheel15. Also, the driver supporting base20moves between a state of being pressed against an outer peripheral surface of the drive wheel15and a state of being apart therefrom by a little distance by a pressing mechanism40described later.FIG. 3shows a state in which the driver supporting base20is positioned apart from the rubber ring17at the outer peripheral surface of the drive wheel15(a state of stand-by operation of the drive wheel15). In the stand-by operation state, in which the driver supporting base20is apart from the drive wheel15(the state shown inFIG. 3), the drive wheel15runs idle and the driving operation is not performed. In contrast, when the driver supporting base20is pressed against the peripheral surface (the rubber ring17) of the drive wheel15with a strong force by the pressing mechanism40, a rotative power of the drive wheel15is converted into a linear movement in the driving direction (downward inFIG. 1) and is transmitted to the driver supporting base20, whereby striking and driving operations of the nail n by the driver21are performed.

The driver21extends downward from the driver supporting base20and a distal end portion thereof reaches inside a drive hole25aof a driver guide25provided at a distal end of the body housing7.

A distal end portion of the magazine5on a supply side is connected to the driver guide25. The nails n-n loaded in the magazine5are pressed by the pushing plate5a, and when the nail n in the drive hole25ais driven out and the driver21is retracted upward, a nail n to be driven next is supplied inside the drive hole25a.

Next, the pressing mechanism40includes an electromagnetic actuator42as a driving source. The electromagnetic actuator42is arranged in a front portion of the body housing7. An output shaft42aof the electromagnetic actuator42is biased toward a protruding side by a conical compression spring42b. When a power is supplied to the electromagnetic actuator42, the output shaft42amoves to a retracting side against the compression spring42b. When the supply of power is interrupted, the output shaft42ais returned to the protruding side by the compression spring42b. The supply of power to the actuator42can be made by a control unit C on the basis of the operation of the trigger4or the contact trip26, which will be described later.

One end side of an operating arm44is connected to a distal end of the output shaft42aof the electromagnetic actuator42via a bracket43so as to be capable of relative rotation. An elongated connecting hole43bis formed in the bracket43in the orthogonal direction1to the extending and retracting directions of the output shaft42a. The one end side of the operating arm44is connected to the bracket43via a connecting shaft43ainserted into the connecting hole43b. Therefore, the one end side of the operating arm44is connected to the bracket43in a state in which the center of rotation can be displaced within such a range that the one end can rotate via the connecting shaft43aand allows the connecting shaft43adefining the center of rotation to move within the connecting hole43b.

The operating arm44is bent in an L-shaped way and extends in the rearward direction (upward inFIG. 1). One end side of a restraining arm46is rotatably connected to the other end side of the operating arm44via a first movable support shaft45. The restraining arm46is rotatably supported by the body housing7via a fixed support shaft47. Also, the other end side of the operating arm44is rotatably connected to a pressing arm50via a second movable support shaft48. The pressing arm50is rotatably supported by the body housing7via a fixed support shaft49. Two pressing rollers41,41are rotatably supported on the side of a distal end with respect to rotation of the pressing arm50(the upper end side inFIG. 1) via a support shaft41a.

According to the pressing mechanism40configured in this manner, in the stand-by state shown inFIG. 1andFIG. 3, the supply of power to the electromagnetic actuator42is interrupted, and hence the output shaft42ais returned to the protruding side by the compression spring42b. In this stand-by state, since the base end side of the operating arm44(the connecting shaft43aside) is displaced obliquely leftward and downward inFIG. 1, the restraining arm46is tilted counterclockwise about the fixed support shaft47, whereby the pressing arm50is tilted counterclockwise about the fixed support shaft49, causing the pressing rollers41,41to be apart from a back surface of the driver supporting base20(a left side surface inFIG. 1) or not to press the driver supporting base20toward the side of the drive wheel15. Therefore, in this state as shown inFIG. 3, the driver supporting base20does not contact with the rubber ring17of the drive wheel15.

In contrast, although not shown, when the power is supplied to the electromagnetic actuator42, the output shaft42ais operated toward the retracting side against the compression spring42b. Then, since a base end side of the operating arm44is displaced obliquely rightward and upward, the restraining arm46is tilted clockwise about the fixed support shaft47, causing the pressing arm50to be tilted clockwise about the fixed support shaft49and the pressing rollers41,41to be brought into a state of being pressed against the back surface of the driver supporting base20. When the pressing rollers41,41are pressed against the back surface, a transmitting portion20aof the driver supporting base20is pressed against the rubber ring17of the drive wheel15with a strong force.

In addition, in this state, the positional relationship among the respective support shafts are set so that the fixed support shaft47of the restraining arm46, the first movable support shaft45as a connecting point to the operating arm44, and the second movable support shaft48as a connecting point to the pressing arm50of the operating arm44are brought into a state of being positioned on a linear line (a toggle mechanism). For this reason, the pressing arm50is locked to a state of pressing the pressing rollers41,41against the back surface of the driver supporting base20, whereby the pressing state of the transmitting portion20aagainst the drive wheel15is firmly maintained.

In this manner, the pressing mechanism40has a function to press the pressing rollers41,41against the back surface of the driver supporting base20, lock this pressing state by the toggle mechanism including the fixed support shaft47, the first movable support shaft45, and the second movable support shaft48, thereby maintaining the pressing state against the drive wheel15of the transmitting portion20a. The transmitting portion20aof the driver supporting base20is pressed against the outer circumference of the drive wheel15with a large force by the pressing mechanism40, whereby the rotational drive force of the drive wheel15is converted into the linear movement in the driving direction of the driver supporting base20, which is output as a driving force for striking the nail n and driving the same into the driven material W.

In this case, an excessive drive torque in the initial stage of movement of the driver supporting base20is absorbed by slipping of the outer wheel15bin the direction of rotation with respect to the inner wheel15aof the drive wheel15, whereby the slipping of the outer wheel15b(the rubber ring17) of the drive wheel15with respect to the transmitting portion20aof the driver supporting base20is restrained, and hence abrasion between the transmitting portion20aand the rubber ring17can be avoided.

Further, the outer wheel15bof the drive wheel15is supported on the outer peripheral side of the inner wheel15avia the rotational force transmitting member in a state of being capable of relative rotation without play. Therefore, since the outer peripheral surface of the inner wheel15acomes in contact with the inner peripheral surface of the outer wheel15bover the substantially entire surface, the stress at the time of transferring the rotational force is dispersed, whereby the abrasion between the outer peripheral surface of the inner wheel15aand the inner peripheral surface of the outer wheel15bis restrained.

At the rear part (upper side ofFIG. 1) of the body housing7, a returning rubber60for upwardly returning the driver supporting base20and the driver21, which have reached a lower limit of movement after having driven the nail n completely, and a winding wheel61for winding the same are provided. One end side of the returning rubber60is connected to the driver supporting base20and the other end side is connected to the winding wheel61. The winding wheel61is rotatably supported by the body housing7via a winding shaft62. The winding wheel61is biased in the winding direction by a spiral spring (not shown) housed therein. A stopper64for restraining the position of a limit of upward movement (a limit of retracting movement) of the driver supporting base20is arranged near the winding wheel61at the rear part of the body housing7. Resilient rubber member is used for the stopper64, which also has a function to absorb an impact produced when the driver supporting base20reaches the position of the limit of the upward movement.

Next, the driver guide25is provided with a contact trip26for preventing an unintended operation of the drive tool1. The contact trip26is supported so as to be movable in the driving direction with respect to the driver guide25, and a lower end portion thereof is biased by a spring in the direction protruding from a distal end of the driver guide25. A trip sensor35for sensing the upward movement of the contact trip26is arranged in the front part of the body housing7as shown inFIG. 2. A well-known limit sensor (a micro switch) is used as the trip sensor35, and it outputs an on-off signal when a sensing bar35ais tilted.

When the drive tool1is pushed toward the driven material W in a state in which the contact trip26is brought into contact with the driven material W, the contact trip26is moved relatively upward against a spring biasing force. This may serve as the first operation.

When the drive tool1is pushed until the distal end of the driver guide25comes into contact with the driven material W to move the contact trip26relatively upward, the trip sensor35is turned on. An on-signal of the trip sensor35is output to the control unit C provided in the body housing7. In addition to the on-off signals of the trip sensor35, operation of the trigger4and operating signals of the electromagnetic actuator42etc. are input to and outputted from the control unit C. The drive control of the respective parts by the control unit C will be described later.

The driver guide25includes a guide base25bfixed in a state of protruding from the distal end of the body portion2and an opening and closing lid25cwhich is supported to be openable and closable with respect to the guide base25b. The drive hole25ais formed between the guide base25band the opening and closing lid25c. The opening and closing lid25ccan be opened when a locking latch25dis unlocked, whereby removal or the like of the driven members n clogged in the drive hole25acan be achieved.

Next, the pull operation of the trigger4is detected by a trigger sensor8. The pull operation of the trigger4may serve as the second operation. When the trigger4is pulled, the trigger sensor8is turned on and the on-signal is output to the control unit C. A well-known micro switch is used as the trigger sensor8.

If the trigger sensor8is turned on by the pull operation of the trigger4and the on-signal is input to the control unit C, and if the contact trip26is turned on and t the on-signal of the trip sensor35is input to the control device, the power is supplied to the electromagnetic actuator42and the driving operation is performed. Thus, the driving operation for the driven member n is performed if both the on operation of the contact trip26(the first operation) and the pull operation of the trigger4(the second pull operation) are performed, and the driving operation is not performed only with either one of these operations.

The pull operation of the trigger4is restricted by the lock lever30. The drive tool1according to the embodiment is greatly characterized in that the lock lever30is provided. The lock lever30and a lock sensor36described later may serve as the locking mechanism.FIG. 1andFIG. 4show a state in which the lock lever30is operated to an unlocked position and the trigger4is pulled. In contrast,FIG. 8shows a state in which the lock lever30is returned to the locked position, so that the pull operation of the trigger4is prohibited. The unlocking operation of the lock lever30may serve as to the third operation.

InFIG. 5andFIG. 6, the lock lever30is shown separately. The lock lever30includes a finger-putting part30aand a functional part30b. A supporting shaft30cis attached to the functional part30bin a state of protruding to the both sides in the width direction. The lock lever30is rotatably supported on the side of a lower surface of the handle portion3and on a lower side of the trigger4(right sides inFIGS. 4 and 8) via the supporting shaft30c. The lock lever30is biased toward the locking side inFIG. 8by a torsion spring37.

As shown inFIG. 5andFIG. 6, the functional part30bis provided with a wide locking part30dand a narrow unlocking part30ein the width direction (direction of axis of the supporting shaft30c, the lateral direction inFIG. 6). Also, a projection30fis provided at a distal end of the finger-putting part30aon a back side. The projection30fhas a cylindrical shape protruding from the back side of the finger-putting part30a, and the distal end portion is formed to be substantially hemispherical.

On the other hand, as shown inFIG. 7andFIG. 9, two engaging parts4a,4aat a certain distance from each other are provided on a lower part (right side inFIG. 1) of the trigger4. The distance between the two engaging parts4a,4ais set to be smaller than the width of the locking part30dof the lock lever30and larger than the width of the unlocking part30e. Therefore, the locking part30dcannot enter between the both engaging parts4a,4aas shown inFIG. 7and, in contrast, the unlocking part30ecan enter between the engaging parts4a,4aas shown inFIG. 9.

When the lock lever30is rotated to the unlocked position as shown inFIG. 1andFIG. 4, the narrow unlocking part30eis positioned on the back side of the engaging parts4a,4aof the trigger4in terms of the direction of the pull operation as shown inFIG. 7. In this state, the unlocking part30ecan enter relatively between the engaging parts4a,4a, and the both engaging parts4a,4ado not interfere with the unlocking part30e, so that the pull operation of the trigger4ccan be achieved.

In contrast, in the state in which the lock lever30is returned to the locked position shown inFIG. 8, the narrow unlocking part30eis retracted from the back side of both the engaging parts4a,4aof the trigger4and the wide locking part30dis positioned as shown inFIG. 9. Since the locking part30dcannot enter between both the engaging parts4a,4a, the pull operation of the trigger4is prohibited by the interference of both the engaging parts4a,4awith the locking part30d.

Even when the unlocking operation of the lock lever30is released after the pull operation of the trigger4, the lock lever30is maintained at the unlocked position since the locking part30dinterferes with both the engaging parts4a,4a. Thereafter, when the pull operation of the trigger4is released, the trigger4is returned to the off-position by a biasing force of the trigger sensor8toward the off-position, whereby the lock lever30is returned toward the locked position shown inFIG. 8by the torsion spring37.

The locked position and the unlocked position of the lock lever30are detected by the lock sensor36. The lock sensor36is also attached in the handle part3. A well-known micro switch is used as the lock sensor36. A detecting button36aof the lock sensor36can be pressed from the outside via a detecting hole3aprovided on the handle part3. The detecting hole3ais provided corresponding to the projection30fof the lock lever30, and when the lock lever30is rotated to the unlocked position shown inFIG. 4, the projection30fenters the sensing hole3a. Therefore, when the lock lever30is rotated to the unlocked position, the projection30fpresses the detecting button36avia the detecting hole3a, whereby the lock sensor36is turned on. When the lock sensor36is turned on, the on-signal is output to the control unit C. On the basis of the on-signal of the lock sensor36that is input to the control unit C, the electric motor11is started and the drive wheel15starts to rotate in a standby state according to the embodiment. When the lock sensor36is turned on, a lighting unit55is illuminated according to the embodiment.

The lighting unit55is arranged at a distal end of the body portion2in the vicinity of the driver guide25as shown inFIG. 10. The lighting unit55is attached in a state of emitting light from within a recess7aprovided on the lateral side of the body housing7toward a distal end portion of the driver guide25and the periphery thereof. In the present embodiment, one LED (light-emitting diode) is used for the lighting unit55. Since the driving portion and the periphery thereof are illuminated brightly by the lighting unit55, the driving operation can be easily made in a dark place, for example, during the night.

In this manner, the lock lever30has a function to switch between the state of allowing the pull operation of the trigger4and the state of prohibiting the same, a function as a switch for turning on the lighting unit55, and a function as a switch for starting the electric motor11. Further, since the lighting unit55is illuminated by the rotating operation of the lock lever30to the unlocked position, the driving portion can be brightly illuminated for confirmation prior to the driving operation.

When a user stops the rotating operation of the lock lever30, the lock lever30is returned to the locked position shown inFIG. 8by the biasing force of the torsion spring37. When the lock lever30is returned to the locked position, the push operation to the detecting button36ais released and the lock sensor36is turned off. When the lock lever30is returned to the locked position, the on-signal from the lock sensor36is interrupted and the above-described lighting unit55is turned off, and the pull operation of the trigger4is brought into a prohibited state as described above.

Next, the operation control of the drive tool1on the basis of the on-off signal of the trip sensor35, the trigger sensor8and the lock sensor36input into the control unit C, etc. will be described. First of all, inFIG. 11, operating states of the electric motor11associated with the operations of the contact trip26, the trigger4, and the lock lever30are shown.

As shown inFIG. 4, when the unlocking operation is performed by tilting the lock lever30downward with the finger tip, the projection30fof the lock lever30pushes the detecting button36aof the lock sensor36, whereby the lock sensor36is turned on. This on signal is input into the control unit C and, on the basis of this, the electric motor11is started. Also, when the lock lever30is unlocked, the lock sensor36is turned on and the lighting unit55is illuminated. In this manner, the lock lever30has both functions as a start switch for the electric motor11and as a lighting switch for the lighting unit55.

On the other hand, as shown inFIG. 8, in a state in which the lock lever30is not unlocked (the locked position), even when the body portion2is pushed downward to turn the contact trip26on (the trip sensor35is turned on), the electric motor11is not started, and only the lighting unit55is lit. When the lock lever30is unlocked after the contact trip26has been turned on, the electric motor11is started.

As described above, when the lock lever30is unlocked, the pull operation of the trigger4is enabled. Therefore, when the lock lever30is unlocked in a state in which the contact trip26is turned on, the electric motor11is started and the drive wheel15starts to rotate in a standby state, and the lighting unit55is lit. Thereafter, when the trigger4is pulled, the electromagnetic actuator42is turned on and the pressing rollers41,41are pressed against the driver supporting base20, whereby the driver supporting base20is moved downward and the driven member n is struck by the driver21so as to be driven into the driven material W.

Further, with the drive tool1according to the present embodiment, by monitoring and controlling the sequence of the on-operation of the contact trip26(turning on the trip sensor35) and the unlocking operation of the lock lever30(turning on the lock sensor36) by the control unit C, an operating mode of the body portion2can be switched to a single shot mode or a continuous shot mode without a troublesome lever operation as in the related art. Also, it is controlled so as not to allow the driving operation in certain sequences of operation.

Referring now toFIG. 12andFIG. 17, various control modes (first to fifth control modes) will be described.FIG. 12shows a list of operating modes of the body portion2for six sequences of operation A to F in the respective control modes.FIG. 13toFIG. 17show flowcharts of the first to fifth control modes.

Symbols used inFIG. 12toFIG. 17will be defined as follows. The contact trip26is abbreviated as “CT”, the lock lever30is abbreviated as “LL”, and the trigger4is abbreviated as “T” respectively. Operations that are not the targets of determination by the control unit C are enclosed with parentheses.

Operation sequences D, E, F inFIG. 12are all erroneous operation sequences, in which the trigger4is pulled before the unlocking operation of the lock lever30, and since these are improper operations which do not lead to normal function of the lock lever30of the drive tool1, no driving operation is performed as a result of “non-operating mode (an error mode)” due to a tool failure (error) in each control mode

In addition, in each of flowcharts inFIG. 13toFIG. 17, an error flag when the tool is defective (for example, as described above, when the trigger4is turned on before the unlocking operation of the lock lever30is made) is expressed as “EF” and EF=1 means defect, a drive complete flag is expressed as “SF” and SF=1 means that the driving is completed, and a lock lever flag is expressed as “LF” and LF=1 means that CT is turned on before LL. Also, a mode switch flag is expressed as “MF”, and the single shot mode is expressed as MF=1.

In the flowcharts shown inFIG. 13toFIG. 17, a symbol ST is affixed to the respective step numbers.

In the first control mode, mode switching between the continuous shot mode and the single shot mode is performed depending on the sequence of on-operations of the contact trip26and the lock lever30. When the lock lever30is turned on and then the contact trip26is turned on, the body portion2is operated in the continuous shot mode. The driving operation of the body portion2is performed by turning the trigger4on in addition to the on-operation of the contact trip26. The sequence of turning ON operation of the trigger4is not involved in the switching of the operating mode.

On the contrary, when the contact trip26is turned on first and then the lock lever30is turned on, the body portion2is operated in the single shot mode. In this case as well, the driving operation of the body portion2is performed by turning the trigger4on in addition to the on-operation of the contact trip26, and the sequence of on-operation of the trigger4is not involved in the switching of the operating mode.

In order to switch the operating mode which is set once as described above, it is necessary to reset the contact trip26and the lock lever30by turning off both of them.

In the second and fourth control modes, regarding the sequences of operation of on-operation of the contact trip26(turning on the trip sensor35), and the unlocking operation of the lock lever30(turning on the lock sensor36, referred to simply as on-operation, hereinafter), and the pull operation of the trigger4(turning on the sensor8, referred to simply as on-operation, hereinafter), the operating mode of the body portion2is determined on the basis of the sequence of operation determined by tracing the sequence of operation back, that is, on the basis of effective three sequences of operation tracing back from the operation immediately before the driving operation of the body portion2for the operation which is reset once (off-operation). Therefore, in the second and fourth control modes, the operating mode can be switched by turning off either of the trigger4or the contact trip26.

On the contrary, in the third and fifth control mode, the operating mode is determined under the similar conditions as the second and fourth control modes. However, switching of the operating mode is performed only from the continuous shot mode to the single shot mode, and the reverse switching mode thereof is not performed. In order to switch the mode from the single shot mode to the continuous shot mode, it is necessary to turn off both the trigger4and the contact trip26once and reset the same. In the second control mode and the third control mode, the body portion2is operated in the same operating mode for the respective sequences of operation, and in the fourth control mode and the fifth control mode, the body portion2is operated in the same operating mode for the respective sequences of operation.

As shown inFIG. 12, the sequence of operation A in the first control mode is a case in which the lock lever30is turned on first, and then the contact trip26is turned on (LL→CT), and in this case, the operation of the body portion2is controlled in the continuous shot mode. In contrast, the sequence of operation C is a case in which the contact trip26is turned on first, and then the lock lever30is turned on (CT→LL), and in this case, the operation of the body portion2is controlled in the single shot mode.

In the sequence of operation B (LL→T→CT), the driving operation of the body portion2is controlled in the continuous shot mode for all control modes.

In the sequence of operation C (CT→LL→T), the driving operation of the body portion2is controlled in the single shot mode for all control modes.

In the sequence of operation A in the second control mode, if the sequence of operation is determined to be such that on-operation of the lock lever30→on-operation of the contact trip26→on-operation of the trigger4(LL→CT→T) for the three operations performed going back in time from the operation performed immediately before a driving operation, the driving operation in the body portion2is not performed.

In the sequence of operation B in the second control mode, if the sequence of operation is determined to be such that unlocking operation of the lock lever30→the pull operation of the trigger4→on-operation of the contact trip26(LL→T→CT) for the same three operations performed going back in time from the operation performed immediately before that, the operating mode of the body portion2is switched to a continuous shot mode. In this continuous shot mode, the driving operation can be performed continuously by repeating the on-operation of the contact trip26.

In the sequence of operation C in the second control mode, if the lock lever30is unlocked and then the trigger4is turned on after the contact trip26is turned on (CT→LL→T) for the same three operations performed going back in time from the operation performed immediately before that, the body portion2is switched to a single shot mode.

In the sequence of operation A in the fourth control mode, if the sequence of operation is determined to be such that unlocking operation of the lock lever30→on-operation of the contact trip26→on-operation of the trigger4(LL→CT→T) for the three operations performed going back in time from the operation performed immediately before that, the operation of the body portion2is controlled in a single shot mode. In the sequences of operations B to F, similar controls as in the second control mode are performed, that is, in the sequence of operation B, the operation is controlled in a continuous shot mode, and in the sequence of operation C, the operation is controlled in a single shot mode.

In the sequences of operation A to F in the third control mode, the sequence of operation is determined on the basis of the three sequences of operation performed immediately after the reset, and the same mode switching as in the second control mode is performed.

In the sequences of operation A to F in the fifth control mode, the sequence of operation is determined on the basis of the three sequences of operation performed immediately after the reset, and the same mode switching as in the fourth control mode is performed.

The respective control modes will be described below according to control flows.

FIG. 13shows the control flow of the first control mode. In the first control mode, the operating mode of the body portion2is controlled on the basis of the sequences of operation of the two members; the contact trip26and the lock lever30. The sequence of operation of on-operation of the trigger4is not involved in the mode switching.

Further, in the first control mode, controlled objects are an error flag EF, a drive complete flag SF, and a mode switch flag MF.

The sequence will be described below from Step100which shows an initial state (non-operation state).

The control flow starts from Step100(hereinafter, simply referred to as ST100). In ST101, the respective flags are reset and the timer counter is reset. In a state in which none of the lock lever30, the contact trip26, and the trigger4is operated, EF=0 is confirmed (diagnose a failure) in ST102, and then, MF is reset to MF=0 in ST103→ST111→ST115, and the timer counter starts in ST116→ST119. Until the timer counter counts 10 seconds in ST120, a control flow of ST102→ST103→ST111→ST115→ST116→ST119→ST120→ST102is repeated. When the elapse of 10 seconds is confirmed in ST120after the timer has started, the electric motor11stops, the drive wheel15stops, and the lighting unit55is turned off, or the stopping and off state of these members are confirmed in ST121.

In the control flow of the non-operating state, the sequence of operation A (LL→CT→T) and the sequence of operation B (LL→T→CT) will be described first. In either sequence of operation A or B, the operating mode of the body portion2is controlled in the continuous shot mode.

In a state in which on-operation of the lock lever30is only performed, when EF=0 (non erroneous operation state) is confirmed in ST102and the unlocking operation of the lock lever30is confirmed in ST103, the timer counter is reset once in ST104, and then, the electric motor11is started, the drive wheel15starts to rotate in a standby state, and the lighting unit55is turned on in ST105. The standby state as described above is controlled in a circulation flow of ST102→ST103→ST104→ST105→ST106→ST122→ST125→ST102.

When the contact trip26is turned ON in this standby state, this is confirmed in ST122, and then, MF=0 is confirmed in ST123and SF=0 is reset in ST124. Therefore, when the trigger4is turned on thereafter, this is confirmed in ST106, and then the fact that SF=0 is confirmed in ST107→ST108, and the driving operation is performed in ST109. After the driving operation, SF is switched to SF=1 in ST110. However, since the procedure does not go to ST111as long as the lock lever30is turned on, MF is maintained at MF=0 and hence the MF=1 is not confirmed in ST123. Therefore, by turning the trigger4off once, the drive complete flag SF is reset in ST124and SF is returned to SF=0. Thus, every time the trigger4is turned on again thereafter, the driving operation can be performed continuously in ST107→ST108→ST109.

Further, as long as the state in which the lock lever30is turned on is maintained, even though the state in which the trigger4is pulled is continued, when on-operation of the contact trip26is released once, SF is reset to SF=0 in ST106→ST107→ST123→ST124, so that the driving operation can be performed continuously in ST107→ST108→ST109every time the contact trip26is turned on again.

In this manner, the drive complete flag which has become SF=1 in ST110is reset to SF=0 in ST124by turning on the trigger4or the contact trip26once, as long as the lock lever30is kept ON and the MF=0 is maintained. The operation control of the continuous shot mode according to the sequence of operation A or the sequence of operation B in the first control mode has been described above.

Next, the sequence of operation C for turning on the contact trip26first and then turning on the lock lever30in the control flow in the non-operating state (ST102→ST103→ST111→ST115→ST119→ST120) will be described. In the sequence of operation C, the operation of the body portion2of the tool is controlled in the single shot mode.

In this case, after having reset the time counting by the timer counter in ST111→ST112, the lighting unit55is turned on in ST113, and the mode switch flag MF is switched to MF=1. Thereafter, when the lock lever30is turned on, the control is made according to the circulation flow of ST103→ST104→ST105→ST106→ST122→ST123→ST102. When the trigger4is pulled in the state of this standby operation, the driving operation is performed in ST106→ST107→ST108→ST109. After having completed the driving operation, the drive complete flag SF is switched to SF=1 in ST110.

Thereafter, when the pull operation of the trigger4is once released while maintaining the state of the on-operation of the contact trip26, MF=1 is confirmed in ST103→ST104→ST105→ST106→ST122→ST123, and hence the flow is returned to ST102. The mode switch flag MF is maintained at MF=1 and the drive complete flag SF is not reset in ST125or ST124, so that the SF=1 is maintained in the control flow. Therefore, since SF=0 is not confirmed in ST106→ST107→ST108even though the trigger4is pulled again, the control flow is returned to ST102, and hence the driving operation is not performed.

In this single shot mode, the drive complete flag SF is needed to be reset to SF=0 in order to perform the driving again and, in order to do so, the on-operation of the trigger4and the contact trip26are all needed to be released once. When the on-operation of these members are all released, the drive complete flag SF is reset to SF=0 in ST103→ST104→ST105→ST106→ST122→ST125. Thereafter, when the on-operations of the contact trip26and the trigger4are performed in this order, the driving is performed again in ST106→ST107→ST108→ST109. Since SF is switched to SF=1 after the driving, the SF is needed to be reset to SF=0 by releasing the on-operation of the trigger4and the contact trip26in order to perform the driving again. In the meantime, the lock lever30is maintained in the on-operation state.

When all of the trigger4, the contact trip26, the lock lever30are released, the control flow of ST102→ST103→ST111→ST115→ST116→ST119→ST120→ST102is maintained for 10 seconds, and then the electric motor11stops, the lighting unit55is turned off, and the drive tool1is returned to the initial state (stopping state) via ST121. The operation control of the single shot mode according to the sequence of operation C in the first control mode has been described above.

In this manner, according to the first control mode, the driving operating mode of the body portion2can be switched to the continuous shot mode or the single shot mode by controlling the sequence of the on-operation of the contact trip26and the lock lever30. The trigger4can be turned on only in a state where the lock lever30is turned on. The operation of the trigger4must be performed only after the operation of the lock lever30is made, and does not involved in the switching of the operating mode. In the first control mode, the operating mode is determined by the sequence of operation of the contact trip26and the lock lever30.

Next, the control flow in the second control mode is shown inFIG. 14. In the second to fifth control modes, the operating mode is switched on the basis of the sequence of operation of the three members; the contact trip26, the lock lever30, and the trigger4. In this regard, these control modes differ from the first control mode described above.

In the second control mode, the targets of control are the error flag EF, the drive complete flag SF, and the lock lever flag LF.

As shown inFIG. 14, when the control flow starts (Step200, hereinafter, simply referred to as ST200), the drive complete flag SF, the tool failure flag EF, and the lock lever flag LF are reset to zero respectively (ST201). Thereafter, the tool failure flag EF is confirmed first (ST202) and, if the unlocking operation of the lock lever30(turning on the lock sensor36) is performed when EF is not EF=1 (ST203), the timer counter is reset in ST204, and then the electric motor11is started and hence the drive wheel15starts to rotates in a standby state and the lighting unit55is turned on in ST205. Thereafter, in the state in which the trigger4and the contact trip26are not turned on, the control flow is returned back to ST202via ST206→ST222→ST225.

In the sequence of operation A, when the contact trip26is turned on in the above-described circulation flow, the drive complete flag SF is switched to SF=1 in the ST222→ST226→ST227, and then the control flow is returned back to ST202. Therefore, even if the trigger4is pulled thereafter, the control flow is returned to ST202while maintaining the state of SF=1 via ST206→ST207→ST208and the driving operation is not performed.

In the sequence of operation B, when the contact trip26is turned on (ST207) after having turned the trigger4on in the state in which the lock lever30is turned on (ST206), SF=0 is confirmed in ST208, and hence the electromagnetic actuator42is turned on in the body portion2, and the driving operation is performed (ST209). After having completed the driving, the drive complete flag SF is switched to SF=1, and the flow returns to ST202. Therefore, by turning off the contact trip26and the trigger4while maintaining the on-operation of the lock lever30thereafter, the drive complete flag SF is returned to SF=0 in ST225, and the state in which the driving is enabled is achieved again. Further, after having completed the driving, when the on-operation of the contact trip26is released while maintaining the on-state of the lock lever30and the trigger4, the drive complete flag SF is reset to SF=0 in ST207→ST228, and by turning on the contact trip26again, the continuous driving can be achieved (continuous shot mode). In this manner, when the trigger4is turned on before turning on the contact trip26according to the sequence of operation B in the second control mode, the operation of the body portion2is controlled in the continuous shot mode.

When the trigger4is turned off first in this continuous shot mode, since the drive complete flag SF is switched to SF=1 via ST206→ST222→ST226→ST227, the driving operation is not performed after that in the same manner as the sequence of operation A.

In the sequence of operation B, when on-operation of the lock lever30, the contact trip26, and the trigger4are all released, the control flow returns to ST202via ST203→ST211→ST215→ST216→ST219→ST220and this flow continues for 10 seconds, and then the electric motor11stops, the drive wheel15stops, and the lighting unit55is turned off in ST221, and the drive tool1returns to the initial state (non-operating state).

In the sequence of operation C in the second control mode (CT→LL→T), firstly by turning on the contact trip26, the lock lever flag LF is switched to LF=1 by ST211→ST212→ST213→ST214and, when the lock lever30is turned on in this state, the control flow is transferred to ST203→ST204→ST205→ST206→ST222→ST226→ST202and, when the trigger4is turned on in this state, the driving operation is performed in ST206→ST207→ST208→ST209. After having completed the driving operation, the drive complete flag SF is switched to SF=1 in ST210and the control flow returns to ST202.

Thereafter, when the on-operation of both the trigger4and the contact trip26is released, the drive complete flag SF is reset to SF=0 in ST206→ST222→ST225and the lock lever flag LF is reset to LF=0. Therefore, when the contact trip26is turned on again and then the trigger4is turned on, the driving operation is performed in ST203→ST204→ST205→ST206→ST207→ST208→ST209.

On the contrary, after having completed the driving operation, even if the trigger4is turned off once after the drive complete flag SF is switched to SF=1 in ST210and is turned on again, the drive complete flag SF is not reset to SF=0 by ST206→ST222→ST226→ST227, so that the driving operation cannot be performed again unless the contact trip26is turned off once (single shot mode).

Next,FIG. 15shows the control flow according to the third control mode. As described above, in the second control mode and the third control mode, the same operating mode is output for the respective sequences of operation.

In the same manner as in the second control mode, the body portion2is not operated in the sequence of operation A (LL→CT→T), and the body portion2is operated in the continuous shot mode in the sequence of operation B (LL→T→CT), and the body portion2is operated in the single shot mode in the sequence of operation C (CT→LL→T).

The third control mode differs from the second control mode in that a mode switch flag MF is added to a controlled object. Also, as is clear when comparingFIG. 14withFIG. 15, the second control mode differs from the third control mode in that the mode switch flag MF is added in ST201, ST215, and ST225, and determination is made in ST230between ST207and ST228, and MF is switched to MF=1 in ST231between ST222and ST226. Other steps which are the same as in the second control mode are designated by the same step number instead of describing again.

In the case of the third control mode, when the operation of the sequence of operation A (LL→CT→T) is performed, since SF is switched to SF=1 via ST203→ST204→ST205→ST206→ST222→ST231→ST226→ST227by turning on the lock lever30and the contact trip26in this sequence, the control flow is returned back in ST206→ST207→ST208→ST202even when the trigger4is pulled thereafter, the driving operation is not performed. In this respect, the third control mode is the same as the second control mode.

When the operation of the sequence of operation B (LL→T→CT) is preformed, the driving operation is performed by ST203→ST204→ST205→ST206→ST207→ST208→ST209. SF is switched to SF=1 in ST210after the driving operation for the first time, and when the contact trip26is turned off thereafter once, SF is reset to SF=0 in ST228, so that the continuous driving operation is enabled by turning on the contact trip26again (continuous shot mode).

When the operation of the sequence of operation C (CT→LL→T) is performed, LF is switched to LF=1, and then the driving operation for the first time is performed by ST203→ST204→ST205→ST206→ST207→ST208→ST209, and SF is switched to SF=1. When the pull operation of the trigger4is turned off once after the driving operation for the first time, MF is switched to MF=1 in ST231, and the control flow returns to ST203in the state of SF=1. Therefore, even if the trigger4is pulled again, the driving operation is not performed since the control flow returns to ST203via ST208(single shot mode). Further, even when the contact trip26is turned off once after the driving is made for the first time, MF is MF=1 is confirmed via ST207→ST230, and hence the control flow returns to ST203and the driving is not performed (single shot mode).

On the contrary, when both the trigger4and the contact trip26are turned off after the driving operation is made for the first time, the respective flags are all reset via ST206→ST222→ST225. Therefore, when both the trigger4and the contact trip26are turned off once while maintaining the lock lever30to be in a on-state, and then the trigger4(the sequence of operation B) or the contact trip26(the sequence of operation A) is turned on again, the sequence of control is switched to the sequence of control B in the former case and to the sequence of control A in the latter case, and hence the operating mode is switched to the continuous shot mode in the former case and to the non-operating mode in the latter case. Further, when the trigger4, the contact trip26, and the lock lever30are all turned off after the driving operation is made for the first time, the elapse of 10 seconds after the trigger is turned off is confirmed in ST216→ST219→ST220and, consequently, the standby rotation of the drive wheel15stops in ST211and the lighting unit55is turned off, so that the drive tool1returns to the initial state.

Next,FIG. 16shows the control flow according to the fourth control mode, andFIG. 17shows the control flow according to the fifth control mode. The fourth and fifth control modes differs from the first to third control modes in that the single shot mode is also output in the sequence of operation A. In the case of the sequence of operation B, the continuous shot mode is output in the same manner as the second and third control modes, and in the case of the sequence of operation C, the single shot mode is output in the same manner as the first to third control modes. In the sequences of operation D, E, and F, the error mode is output, and the body portion2is not operated.

In the case of the fourth and fifth modes, the lock lever flag LF is excluded from a controlled object. In the fourth control mode, the body portion2is controlled on the basis of the two flags; the error flag EF and the drive complete flag SF. The fifth control mode differs from the fourth control mode in that the mode switch flag MF is added to a controlled object. Therefore, the control flow in the fourth control mode shown inFIG. 16differs from the control flow in the second control mode shown inFIG. 14in that ST201, ST215, ST225are different (ST240, ST241, ST242) and ST214, ST226, and ST227are omitted. Further, the control flow in the fifth control mode shown inFIG. 17differs from the control flow in the third control mode shown inFIG. 15in that ST201, ST215, ST225are different and ST214, ST226, and ST227are omitted. The steps which are not needed to be changed are designated by the same step numbers instead of describing again.

In the case of the fourth and fifth control modes, when the operation of the sequence of operation A (LL→CT→T) is performed, the control flow returns to ST202via ST203→ST204→ST205→ST206→ST222by the operation of LL→CT first, and then when the trigger4is turned on, the driving operation for the first time is performed in ST206→ST207→ST208→ST209. When the driving operation is completed, SF is switched to SF=1.

Even when the on-operation of the trigger4is released once thereafter, since the control flow returns to ST202while maintaining SF=1, the control flow is returned in ST208→ST202and the driving operation is not performed (single shot mode) even when the trigger4is turned on again thereafter. In this respect, the fourth control mode is the same as the fifth control mode.

In the case of the fourth control mode, when the on-operation of the contact trip26is released once after the driving operation is made for the first time, the sequence of operation is switched to sequence of operation B because SF is reset to SF=0 by ST207→ST228, so that when the contact trip26is turned on again, the driving operation is performed in the continuous shot mode.

On the contrary, in the case of the fifth control mode, since the MF is switched to MF=1 in ST231and this state is maintained, even when on-operation of the contact trip26is released once after the driving operation is made for the first time, the control flow is returned in ST230→ST202and SF is not switched to SF=0, so that the driving operation is not performed and hence the single shot mode is maintained. In the case of the fifth control mode, SF and MF are switched to SF=0 and MF=0 via ST206→ST222→ST252by releasing the on-operation of both the trigger4and the contact trip26, so that the driving operation after that is enabled.

In the fourth and fifth control modes, the operations when the sequence of operation B (LL→T→CT) and the sequence of operation C (CT→LL→T) are performed are basically the same as those in the second and third control modes, and hence the description is omitted.

According to the electric drive tool1in the embodiment as described thus far, in order to turn on the trigger4, the lock lever30attached therewith is needed to be unlocked (on-operation), so that an unintended pull operation of the trigger4is prevented and thus an erroneous operation of the electric drive tool1is prevented.

Further, according to the first control mode of the electric drive tool as exemplified, switching between a continuous shot mode and a single shot mode can be made by changing an operational sequence of the first operation and the third operation. Conventionally, a specially provided mode switching lever is needed to be operated, and it was troublesome for operation, but according to the first control mode as exemplified, the operating mode can be switched based on the operational sequence between the on-operation of the contact trip26and the on-operation of the lock lever30, which restricts the on-operation of the trigger4, not based on the on-operation of the trigger4. In this respect, the switching operation of the operating mode can be rapidly and easily performed than previously made.

In the second to fifth control modes, switching between the continuous shot mode and the single shot mode can be made by changing the operational sequence of the three operations including the on-operation of the contact trip26(first operation), the pull operation of the trigger4(second operation) and the unlock operation of the lock lever30(third operation), and therefore, the function of the locking mechanism can be increased and further diversification of the switching mechanism for the operating mode can be achieved.

Further, in the second control mode or the fourth control mode, the operating mode can be switched based on the operational sequence just before the performance of the driving operation. Therefore, the operating mode can be switched without resetting all of the on-operation of the contact trip26, the on-operation of the trigger4, and the on-operation of the lock lever30by maintaining either one of them in the on-state and changing the operational sequence of the other two operations.

On the other hand, in the third control mode or the fifth control mode, unintended switching to the continuous shot mode is not made because the operating mode can be switched preferentially to the single shot mode. In this respect, the third or fifth control mode is meaningful.

Further, the pull operation of the trigger4is restricted by the lock lever30of the locking mechanism. That is, the pull operation of the trigger4cannot be performed unless the unlock operation of the lock lever30(on-operation) is performed. However, in the case that damage of the locking mechanism etc. has caused the trigger4to be pulled while the lock lever30is not operated to be unlocked trigger lock state) (operational sequence D, E, F), it is all determined to be an error mode and the driving operation cannot be performed by the main body2, and therefore, an erroneous operation of the trigger4can be reliably prevented, and furthermore an unintended driving operation of the main body2can be prevented.

Various modifications can be made to the embodiment described above. For example, the lock lever30is exemplified as a locking mechanism for restricting the pull operation of the trigger4, a configuration in which a push button or a slide lever is used as a locking mechanism can be applied as well.

Further, the drive wheel15is exemplified which has the double structure including the inner wheel15aand the outer wheel15b, but the locking mechanism can also be applied to a driving mechanism having a drive wheel of an integral structure.