Abstract: When a movable sleeve 11 on a cylinder moves upward, a combustion chamber 5 in a sealed state is formed. Mixed gas is explosively burnt within the combustion chamber 5 so as to drive a fastener out. A lock cylinder 22 is disposed beneath the movable sleeve 11. A lock piston 23 is housed within the lock cylinder 22 so as to be movable in an up/down direction. The upper end of the lock piston 23 is capable of being engaged with a holding member 12 which is interlocked with the movable sleeve 11. The lower portion of the lock cylinder is coupled to the combustion chamber via a gas tube 24. The gas tube 24 is provided with a check valve 25. The lock cylinder 22 is provided with an electromagnetic valve 27. The electromagnetic valve 27 opens upon the lapse of a predetermined time period after the combustion within the combustion chamber.

Abstract: There is provided a fastening tool including a tool body and a combustion housing defining a combustion chamber. A barrel is connected to the combustion housing and includes a barrel opening configured to receive a fastener. The tool also includes a power source configured to generate a power source signal. A power regulator is in electrical communication with the power source and is configured to receive the power source signal and transmit a power regulator output having an output magnitude. A manual power control is in operative communication with the power regulator and is configured to adjust the power regulator output magnitude. A spark generator is in electrical communication with the power regulator and is configured to generate a spark within the combustion chamber upon receipt of the power output from the power regulator. The spark includes a spark magnitude that varies in response to the power output magnitude.

Abstract: An explosive discharge actuated tool for driving fasteners has a barrel with a closed bore, an interchangeable nose piece to accommodate different length fasteners and a piston that is manually reset to firing position by a spacer-fastener being inserted into the barrel.

Abstract: An adapter configured for use in combination with a cap on a fuel cell having a closure formation, the cap having at least one leg portion and a corresponding foot extending from the leg, including a ring portion configured for engagement upon the closure formation of the fuel cell and including a top edge, a bottom edge, and a sidewall therebetween having an inner sidewall and an outer sidewall, a grooved portion defined by the inner sidewall, a convex gripping formation on the outer sidewall complementary to the closure formation, and at least one recessed formation adjacent the grooved portion for receiving the foot.

Abstract: A safety is incorporated in a nailing device, which ensures operation safety of the nailing device. The nailing device includes a housing containing a striker plate movable to a ready-to-strike position for subsequently striking a nail. The safety includes a retainer having an inclination engageable with a mated inclination formed on a release plate that is normally biased to partially project out of the housing, so that a stop of the retainer is set at a position to block the striker plate from moving toward the ready-to-striker position. When the nailing device is properly set on a work piece, the release plate is forced by the work piece back into the housing and the retainer is rotated by the camming action between the mated inclination faces so as to move the stop aside to allow the striker plate to move to the ready-to-strike position.

Abstract: A motor mount for suspending a fan motor in a combustion-powered tool includes an inner ring for securing to the motor, an outer ring that is secured to a portion of the tool, and a web portion disposed between and connecting the inner ring and outer ring. The inner ring, outer ring, and web portion are formed as a unitary piece. Preferably, the mount is formed of a thermoplastic polyester elastomer.

Abstract: A combustion-operated setting tool (10) for driving-in fastening elements includes a setting piston (14) displaceable in a guide cylinder (13), a combustion chamber (15), a fuel inlet (23) opening into the combustion chamber (15) for feeding fuel therein and an ignition element (26) for igniting the fuel in the combustion chamber (15), both located at the first end (31) of the combustion chamber (15) adjacent to the guide cylinder (13), and a motor-driven ventilator (16) supported on a rear wall (30) of the combustion chamber (15) at the second end (32) of the combustion chamber (15) remote from the guide cylinder (13).

Abstract: A hand-held drive-in tool for driving fastening elements, includes a driving ram (13) displaceably arranged in a guide (12), a drive unit (14) for displacing the driving ram (13), a press-on element (20) for controlling the safety element (23) of the drive unit (14) and spring-biased in a drive-in direction, and a device for changing a biasing force applied to the press-on element (20) dependent on a special orientation of the press-on element (20) relative to a vector (G) of a gravitational force.

Abstract: In a gas combustion type driving tool, on a feed cylinder 21 included in a feed piston/cylinder device 7, there is provided a spring for normally urging a feed piston 22 in a feed direction. A portion of the feed cylinder 21 opposite to the spring is connected to a combustion chamber 5 through a gas conduit 26. In an intermediate portion of the gas conduit 26, there is provided a delay piston/cylinder device A. One end of a delay cylinder 27 is disposed on the combustion chamber 5 side, while the other end thereof is disposed on the feed cylinder 21 side. When a delay piston 28 is slidingly moved from one end of the delay cylinder 27 to the other end thereof by the pressure of combustion gas, air compressed within the delay cylinder 27 is supplied from the other end of the delay cylinder 27 to the feed cylinder 21.

Abstract: A combustion-powered fastener-driving tool includes a power source including a cylinder and a valve sleeve reciprocating relative to the cylinder between a closed position defining and closing a combustion chamber, and an open position allowing venting of the combustion chamber. A lockout device is associated with the power source and is configured for releasably restraining the valve sleeve in the closed position. A control system is connected to the power source, is operable in both a sequential firing mode and a repetitive firing mode, and is configured for activating the lockout device in a first format when in the sequential firing mode, and in a second format when in the repetitive firing mode.

Abstract: A housing for a power tool having a power source, includes a fuel cell chamber configured for attachment to the power source and dimensioned for operationally receiving a fuel cell in either one of a first orientation and a second orientation.

Abstract: A filter element for a combustion tool includes a filter medium having pores with a pore size greater than a target particle size.

Abstract: A driving machine has a work contact portion with an end face to be contacted with a member to be fastened that is provided in a push lever, and a probe movably provided on the work contact portion, wherein the probe is energized in the driving direction by a spring to thereby project its leading end portion from the end face of the work contact portion. When the main body of the driving machine is pressed against a work, the probe is retreated from the driving passage of a fastening member when a tripper switch is operated.

Abstract: A portable linear fastener driving tool is provided that drive staples, nails, or other linearly driven fasteners. The tool uses a gas spring principle, in which a cylinder filled with compressed gas is used to quickly force a piston through a driving stroke movement, while a driver also drives a fastener into a workpiece. The piston/driver is then moved back to its starting position by use of a rotary-to-linear lifter, and the piston again compresses the gas above the piston, thereby preparing the tool for another driving stroke. The driver has protrusions along its edges that contact the lifter, which lifts the driver during a return stroke. A pivotable latch is controlled to move into either an interfering position or a non-interfering position with respect to the driver protrusions, and acts as a safety device, by preventing the driver from making a full driving stroke at an improper time.

Abstract: A combustion type power tool capable of avoiding wasteful injection of combustible gas from a gas canister even if an unintentional operation of the push lever takes place, and capable of avoiding wasteful electric power consumption even if a battery used as power supply remains set in the tool. While the tool is not being used, a stop unit is set at a stop position, preventing a gas canister from injecting gas, and while the tool is being used, the stop unit is set at a release position, allowing the gas canister to inject gas as a result of movement of a combustion chamber frame.

Abstract: A combustion-powered fastener-driving tool includes a combustion-powered power source, a workpiece contact element reciprocable relative to the power source between a rest position and a firing position, a control system operationally associated with the power source, a trigger connected to the control system providing operator interface with the control system. The control system is configured so that an operator may select between a sequential firing mode in which the trigger must be released between firings, and a repetitive cycle mode in which the trigger is continually depressed between firings. The trigger is connected to the control system so that at least one of the frequency and duration of pulling of the trigger converts the operating mode from the sequential mode to the repetitive cycle mode.

Abstract: By moving a movable sleeve 10 provided above a driving cylinder 3 in a vertical direction so as to come into contact with a cylinder head 8 above the driving cylinder 3, a combustion chamber 6 becomes a closed state. When mixed gas obtained by stirring and mixing air and fuel gas by a rotary fan 21 is ignited by a spark plug 20 so as to be burned explosively in the combustion chamber 6, high-pressure combustion gas is applied to a driving piston 4 to impulsively drive the driving piston 4 so that a driver 5 coupled to a lower surface of the driving piston 4 drives a fastener. An upper wall surface on an outer portion of the combustion chamber 6 is disposed at a position far away from the spark plug 20 so that a flow speed of the mixed gas passing the upper wall surface decreases to the extent that an ignition when the mixed gas arrives at the spark plug 20 is not interrupted. An opening groove 22 is formed in the upper wall surface so as to be opened to the combustion chamber 6.

Abstract: A pneumatic fastener includes a housing and a handle coupled to the housing. The handle defines an inlet channel for delivering compressed gas to the housing. A trigger valve is in communication with the inlet channel and configured to actuate the pneumatic fastener. A fastener driving assembly is disposed within the housing. The fastener driving assembly includes a cylinder and a piston that reciprocates within the cylinder to drive a fastener. A valve piston is coupled to the fastener driving assembly. Actuation of the valve piston causes compressed air to drive the piston within the cylinder to drive the fastener. An outer cap is coupled to the housing and an inner cap is disposed at least partially within the outer cap. The inner cap includes an opening in communication with the trigger valve for porting the compressed air to a region above the valve piston.

Abstract: A combustion-type power tool includes a housing, a cylinder head disposed at one end of the housing, a cylinder in the housing, a piston slidably disposed in the cylinder, and a driver blade connected to the piston. A combustion-chamber is provided in the housing, a fan is disposed in the combustion chamber, and a motor having an output shaft is coupled to the fan. A motor holder accommodates the motor, and the cylinder head is formed with a motor holder receiving portion in which the motor holder is slidably movably disposed. An elastic member is disposed in a gap formed between the motor holder and the motor holder receiving portion.

Abstract: In a gas combustion type driving tool, on a feed cylinder 21 included in a feed piston/cylinder device 7, there is provided a spring for normally urging a feed piston 22 in a feed direction. A portion of the feed cylinder 21 opposite to the spring is connected to a combustion chamber 5 through a gas conduit 26. In an intermediate portion of the gas conduit 26, there is provided a delay piston/cylinder device A. One end of a delay cylinder 27 is disposed on the combustion chamber 5 side, while the other end thereof is disposed on the feed cylinder 21 side. When a delay piston 28 is slidingly moved from one end of the delay cylinder 27 to the other end thereof by the pressure of combustion gas, air compressed within the delay cylinder 27 is supplied from the other end of the delay cylinder 27 to the feed cylinder 21.

Abstract: A combustion-powered fastener-driving tool includes a combustion-powered power source, at least one fan for associated with the power source, at least one temperature sensing device in operational proximity to the power source and a control system operationally associated with the power source and connected to the at least one fan and at least one temperature sensing device for adjusting the length of time for energizing the at least one cooling fan as a function of power source temperature sensed by the at least one temperature sensing device.

Abstract: A combustion-type power tool includes a housing having one end, a head portion disposed at the one end, and a cylinder disposed in the housing, the cylinder being formed with an exhaust hole. A piston is reciprocally movable in the cylinder, and a combustion-chamber frame is disposed in the housing and movable in an axial direction of the cylinder, the combustion-chamber frame being abuttable on the head portion to provide a combustion chamber in cooperation with the head portion and the piston. A fin is disposed on the cylinder and has a portion extending in a direction slanted in relation to the axial direction and oriented toward the exhaust hole.

Abstract: A combustion-powered fastener-driving tool includes a combustion-powered power source, a valve sleeve reciprocable relative to the power source between a rest position and a firing position, and a lockout device in operational proximity to the valve sleeve and configured for automatically preventing the reciprocation of the valve sleeve from the firing position until a piston in the power source returns to a pre-firing position.

Abstract: A front portion of a feed cylinder of a feed piston-cylinder mechanism is communicated with a combustion chamber, and a rear portion of the feed cylinder is sealed. A check valve and a spring which constantly biases a feed piston toward a nail feed direction in the forward direction are provided. An opening valve communicating with the rear portion of the feed cylinder is provided. The opening valve is opened after or just before a completion of a returning operation of a striking piston.

Abstract: A containing portion 22 for a motor is formed at an upper wall of a combustion chamber 11 of a gas combustion type striking machine. A shaft 21 of a motor 20 is coupled with a rotating fan 18 penetrated through a bottom portion of the containing portion 22 to face the combustion chamber 11. A mixture gas provided by being agitated and mixed by the rotating fan 18 is ignited and combusted at inside of the combustion chamber 11. A fastener is struck by a pressure of a combustion gas produced by the combustion. The motor 20 is contained in the containing portion 22 by way of damping members 25, 26 in a shape of a short cylinder respectively having an elasticity at upper and lower portions thereof. The respective damping members 25, 26 are formed with a plural of groove holes 28 prolonged in an up and down direction at constant intervals along a peripheral direction.

Abstract: A combustion-engined setting tool for driving fastening elements in a constructional component includes at least one combustion chamber (11) for receiving an oxidant-fuel gas mixture, a piston guide (17) located adjacent to the combustion chamber (11), and in which a drive piston (15) for driving the fastening elements in is displaceable by combustion gases, a ventilator for creating turbulence in the combustion chamber (11), and a compression device (30) for compressing gases fed into the combustion chamber (11) and driven by the ventilator drive (21).

Abstract: A main switch section is accommodated in a trigger. The trigger provided on the handle through a spring. The handle is formed with a recess to which one end of the spring is seated, so that the trigger is normally urged toward the lower side of the combustion-type nail driver. A switch accommodating portion is provided in the lower side of the canister housing. A push switch is stored in the switch accommodating portion. The push switch is a commodity type micro-switch covered with a switch protection member made from an elastic material such as a rubber.

Abstract: A combustion nailer is configured for use with a fuel cell having an internal metering valve and a reciprocating, biased main stem. The nailer includes a tool housing defining a fuel cell chamber constructed and arranged for receiving the fuel cell, a fuel cell actuator assembly configured for actuating the fuel cell in the chamber to emit a measured dose of fuel during tool operation, and a fuel delivery apparatus associated with the actuator assembly for receiving the emitted dose of fuel and providing it to a combustion chamber. The fuel delivery apparatus is configured for preventing actuation of the main stem by the actuator assembly upon the fuel cell being adapter-free.

Abstract: A combustion-operated setting tool (10) for driving in fastening elements, includes a combustion drive for driving a setting piston (13) displaceable in a guide cylinder (12) and which drive has at least one combustion chamber (14), a ventilator (16) for the combustion drive, a control unit (30) for controlling the ventilator (16) dependent on a thermal control parameter and having a program for modeling the thermal control parameter based on time data and ventilator operation data.

Abstract: A combustion type driving tool including a combustion chamber frame which is provided in a housing, and can move in one direction and in the other direction thereby to define a combustion chamber when it has moved in the other direction, moving means which can select either of a manual operation valid state and a manual operation invalid state, and permits the combustion chamber frame to move in the other direction by manual operation, only in the manual operation valid state, and a link mechanism.

Abstract: A combustion nailer is configured for use with a fuel cell having an internal metering valve and a reciprocating, biased main stem. The nailer includes a tool housing defining a fuel cell chamber constructed and arranged for receiving the fuel cell, a fuel cell actuator assembly configured for actuating the fuel cell in the chamber to emit a measured dose of fuel during tool operation, and a fuel delivery apparatus associated with the actuator assembly for receiving the emitted dose of fuel and providing it to a combustion chamber. The fuel delivery apparatus is configured for preventing actuation of the main stem by the actuator assembly upon the fuel cell being adapter-free.

Abstract: A nailing machine includes a contact rod substantially in a straight shape and an operating dial. The contact rod is slidably and rotatably supported by a nose portion. The operating dial is slidably penetrated to be inserted by the contact rod, rotatably provided integrally with the contact rod and provided rotatably and by being restricted from being moved in an up and down direction with respect to the nose portion. A length of projecting the contact member in a direction of a front end of the nose portion is adjusted by rotating the contact rod by way of the operating dial.

Abstract: In a gas combustion type striking tool which strikes a fastener supplied in a nose portion into a member to be fastened by burning mixed gas inside a combustion chamber above a striking cylinder in accordance with a pulling operation of a trigger lever to drive a striking piston and a driver by a pressure of the combustion gas thus generated, a topper is disposed so as to be able to protrude into a path of a feed pawl or a feed piston, and a stopper engaging member, which extends downward from the striking cylinder and is movable in a vertical direction, engages with the stopper when the stopper engaging member moves downward, thereby retracting the stopper from the path.

Abstract: A gas nailer is provided with a driving cylinder 7, a driving piston 10, a combustion chamber 8, a gas fuel cartridge 2, and a supercharging device 3. The driving piston 10 is operated in the driving cylinder 7 by a combustion pressure generated when a mixture of gas fuel and air is burned in the combustion chamber 8, and a driver hammers a fastener by an operation of the driving piston. A locking device 15 for locking the driving piston 10 is provided in the driving cylinder 7 so as not to move the driving piston 10 in accordance with a pressure increase in the combustion chamber 8 during a supercharging operation in which compressed air is supplied by the supercharging device 3.

Abstract: A combustion-powered, fastener-driving tool includes a cylinder and a combustion chamber disposed on top of the cylinder that accommodates a gaseous mixture of existing air in the combustion chamber and fuel injected therein. A spark plug generates a spark to combust the gaseous mixture in the combustion chamber. A trigger produces the spark in the spark plug when operated. A piston is movably supported in the cylinder and driven by combustion in the combustion chamber. A driving blade is coupled to the piston for driving a fastener. A spark controller is provided for generating a plurality of sparks in succession with the spark plug.

Abstract: The combustion type power tool includes a housing accommodating a combustion chamber and an ignition plug for igniting a combustion gas supplied into the combustion chamber. In the housing is defined a lithium ion battery accommodating part for causing the ignition plug to generate ignition energy. The housing includes a handle part. The lithium ion battery accommodating part is arranged at the free end of the handle part.

Abstract: An explosive discharge actuated tool for driving fasteners has a barrel with a closed bore, an interchangeable nose piece to accommodate different length fasteners and a piston that is manually reset to firing position by a spacer-fastener being inserted into the barrel.

Abstract: It is an object of the present invention to provide a combustion power tool having a rational construction. A representative combustion power tool according to the invention may include a combustion chamber, a fuel supplier to supply fuel into the combustion chamber, an igniter disposed in the combustion chamber, a driving mechanism actuated to perform a predetermined operation by utilizing a combustion pressure generated when the fuel is burned in the combustion chamber and an actuator that operates the fuel supplier and the igniter in one operation. Based on the operation of the actuator, fuel is supplied into the combustion chamber via the fuel supplier and the igniter performs ignition in relation to the pressure of the fuel supplied into the combustion chamber changes. According to the invention, because the fuel supplying and ignition can be done by the actuator in one operation, ignition can be performed in constant timing after fuel is supplied via the fuel supplying means.

Abstract: A combustion type power tool capable of restraining reduction in output power due to lowering of combustion efficiency. A specific space within a combustion-chamber frame is enlarged. The specific space contains a specific region where high turbulence occurs in a combustion chamber at which a fuel is ignited. The enlargement is made by providing an enlarged distance between a rotation shaft of the fan and an inner wall of the combustion-chamber frame. When the turbulent combustion occurring at the specific region is expanded in the combustion chamber, flame propagation contour of the turbulent combustion reaches the wall of the combustion-chamber frame and ribs at a delayed timing. Therefore, after the turbulent combustion is sufficiently promoted, the flame reaches the combustion-chamber frame and the ribs. In other words, the flame does not reach the combustion-chamber frame and the ribs at the initial stage of turbulent combustion.

Abstract: A combustion-type power tool includes a housing, a head portion, a cylinder disposed in the housing, and a push lever. A piston is reciprocally movable in the cylinder, and a combustion-chamber frame is disposed in the housing and abuttable on the head portion to provide a combustion chamber in cooperation with the head portion and the piston. A fuel supplying portion supplies the fuel into the combustion chamber, a motor is disposed at the head portion, and a fan is disposed in the combustion chamber and connected to an output shaft of the motor so as to promote turbulent combustion of an air-fuel mixture. The fan and the combustion-chamber frame define a high turbulent-combustion region and a low turbulent-combustion region, a fin of one shape is located within the low turbulent-combustion region, and another fin of another shape has a part thereof located in the high turbulent-combustion region.

Abstract: The apparatus comprises of a barrel and means (3, 5) of driving a fastening element in the barrel, a handle (9) which includes means (25, 33) for receiving a removable feed magazine (4) for fastening elements, in which the forward part (3) of the apparatus is arranged to cooperate with a feed end (55) of the magazine (4) and to ensure that a fastening element is transferred from the magazine (4) into the barrel (1), with the free end (33) of the handle (9) away from the barrel being arranged so that the other loading end (54) of the magazine (4) may be secured thereto. The free end (33) of the handle (9) carries a fixing rod (47) for the aforementioned loading end (54) of the magazine (4), with the rod (47) being fitted so that it pivots and alters the relative position of the free end of the handle (33) and of the loading end (54) of the magazine. There is compensation for all dimensional tolerances thanks to this invention.

Abstract: It is an object of the invention to provide a reliable ignition by a spark plug in a combustion power tool. Representative combustion power tool may comprise a combustion chamber, a gas supply section, a single spark plug, an ignition control device, a cylinder connected to the combustion chamber, a piston member and a tool member. The ignition control device includes a plurality of ignition circuits connected to the single spark plug to independently input power to the spark plug, and a control section that controls the manner of power input in each of the ignition circuits. According to such construction, power input in each of the ignition circuits can be controlled and therefore, a desired power output at the single spark plug can be realized.

Abstract: The indirect fire device for fixing fasteners (13) in a substrate material of the invention comprises a piston for driving a fastener (13) movably mounted in a barrel and a plug guide (11) for guiding a fastener (13) towards the substrate material. The device is adapted to receive a magazine (19) for receiving a strip (14) of fasteners (13) in order to introduce the fasteners (13) one by one into the plug guide (11). Each fastener (13) is held in a sleeve comprising bridges (16) for connection to another sleeve (15). The plug guide (11) of the device includes a zone having an enlarged circular section (21) at the opening of the magazine (19) leading into the plug guide (11), extending axially over the length (h) of a sleeve (15) increased by the stroke of the plug guide (11) for loading the device (L-L?).

Abstract: A tool is provided with a barrel having a piston for driving a fastener into a substrate, the barrel being mounted for axial movement within a body of the tool and a nose piece being mounted forwardly of the barrel and being at least partially encapsulated by a base plate that connects to the receiver of the tool which encloses the barrel and piston, the present invention permiting ease of assembly and disassembly of the muzzle of the tool—the nose piece and base plate—by making the connection between the base plate and the receiver with a retainer element.

Abstract: The tool comprises a piston which can be propelled under the action of the explosion of a mixture of gas and air to drive an element, a first, gas-metering chamber, a second, gas-air mixture-preparation chamber, designed to communicate with the first chamber, and a third chamber designed to communicate with the second chamber, which is delimited by the piston and which is a throttling and propulsion chamber. The invention is ideally applicable to securing tools.

Abstract: It is an object of the invention to provide a technique for preventing power tool from being operated by a malfunction of the control circuit. A representative driving power tool includes a movable element, a drive unit to drive the movable element, an actuation circuit to actuate the drive unit, a control circuit and an operation switch that outputs an operation signal. The control circuit outputs a control signal when the operation signal for instructing driving of the movable element is outputted from the operation switch. The actuation circuit actuates the drive unit when the control signal is outputted from the control circuit. Actuation of the drive unit is blocked when the control signal outputted from the control circuit is abnormal. According to the invention, a movable element can be prevented from being moved by malfunctioning of the control circuit.

Abstract: A combustion-powered fastener-driving tool includes a combustion-powered power source; at least one fan associated with the power source during operation; and a control system operationally associated with the power source and connected to the at least one fan for adjusting the length of time for energizing the at least one fan as a function of the number of combustion firings by the power source.

Abstract: The tool includes a cylinder inside of which is slidably mounted a piston for driving a fastening element, as a result of the explosion inside of a combustion chamber of a mixture of gas and air that has been injected therein from a gas cartridge, after which the tool has come to bear weight against a support, the head switch has retracted and the combustion chamber has closed, followed by actuation of the trigger switch for controlling the spark plug. The tool also includes an element for determining the rate of fire which includes a real-time clock designed to cooperate with a microcontroller of an operating and control module. The arrangement applies well to fastening tools.

Abstract: An exhaust check valve and piston return system wherein a main exhaust valve is opened as a result of combustion products from the combustion chamber being routed through a signal line. In addition, as a result of the opening of the main exhaust valve, an exhaust check valve, incorporated within a side wall portion of the cylinder housing at a location disposed downstream of the main exhaust valve, as considered in the direction of flow of the exhaust gases out from the combustion chamber, is forced to its open position so as to permit the combustion gases to be exhausted from the combustion chamber, thereby permitting the piston to move upwardly so as to complete its return stroke.

Abstract: A combustion-powered nail gun drives nails into a workpiece when both a head switch and a trigger switch are turned ON while a safety switch is turned ON. The nail driving operation cannot be performed if the safety switch is not ON even if both the head switch and the trigger switch are ON. The head switch is turned ON when a push lever is urged against the workpiece. Fuel/air mixture in a combustion chamber is ignited when the head switch and the trigger switch are turned ON irrespective of an order in which the head switch and the trigger switch are turned ON, whereby “successive-shot driving” can be performed in which the trigger switch is maintained in its ON position while successively driving a plurality of nails at different locations of the workpiece by repeatedly pushing and releasing the push lever toward and away from the workpiece.