Abstract: In the combustion-type power tool, a first shelter wall and a second shelter wall are disposed to partially surround an area between an ignition plug and an ignition ground. Two gaps are provided between the first and second shelter walls. The first shelter wall extends radially outwardly from an outer peripheral surface of a motor boss, and also protrudes from an end face in an axial direction of a fan shaft. The first shelter wall has a lower end surface inclined such that an axial length between the end face and the lower end surface is gradually reduced toward radially outer end of the first shelter wall.

Abstract: A spark is shot between an ignition point of an ignition plug and an ignition ground. The spark is shot from an acute corner of a core of the ignition plug. A tip end of the core has an acute angle of not more than 45 degrees. With this arrangement, an emitting point of the spark can be concentrated to the tip end of the core. In order to reduce a thermal capacity of the ignition ground so as to enhance ignitability, a side opposite to the spark seating face of the ignition ground is tapered to provide an angle. Further, the ignition ground has an apex end providing an angle which is not more than 45 degrees. Because of the apex portion, thermal capacity of the ignition ground can be reduced and an acute angle can be realized to concentrate spark receiving point at the apex portion. As a result, ignitability can be enhanced.

Abstract: A combustion-type power tool includes a housing, a cylinder, a cylinder head, a combustion chamber frame, and a rotatable fan. The combustion chamber frame including a base section, a head section abuttable on the cylinder head to provide a combustion chamber when the combustion chamber frame is at a first position, and a connection portion for connecting the head section with the base section. The fan includes fan blades which define a widthwise center line and having widthwise edge portions which define a widthwise edge line at a side of the cylinder head. The widthwise center line is offset from the connection portion toward another end of the housing, and the widthwise edge line is offset from the connection portion toward the cylinder head when the combustion chamber frame is at a second position.

Abstract: A combustion-type power tool includes a housing, a cylinder disposed, a piston, and a cylinder head disposed at an end of the housing and having a wall portion extending in a direction perpendicular to an axial direction, the wall portion having an opening. A motor is disposed at the cylinder head and includes a motor body and a drive shaft extending from the motor body into a combustion chamber through the opening of the wall portion of the cylinder head, a fan is connected to the drive shaft to be rotatable within the combustion chamber, and an elastic member is disposed at the opening of the wall portion and has a sleeve portion extending in the axial direction. The sleeve portion has a through-hole through which the drive shaft extends, and an inner surface of the through-hole is tapered with respect to an outer surface of the drive shaft.

Abstract: A miter saw capable of reducing scattering amount of cutting chips at a terminal phase of cutting operation. The miter saw includes a base section for supporting a workpiece, a cutting section, and a support section for supporting the cutting section. The support section includes a slide support part extending from the base section, and a pivot support part for pivotally movably supporting the cutting section. The cutting section includes a cutting chip inflow part. A guard extends from the slide support part. The guard has a slope portion for guiding cutting chips toward the inflow part. The slope portion is positioned on an extension of an intersection line defined between the base section and a saw blade and is movable in the direction of the intersection line.

Abstract: A combustion-type power tool having a cooling arrangement for cooling a cylinder. The tool includes a housing, a cylinder head at one end of the housing, a push lever disposed at another end of the housing, and a combustion chamber frame including a base section and a head section. The head section has a disc like connecting portion extending from an end of the base section and a sleeve like abutment section extending from the connecting portion toward a cylinder head. A fan is disposed in a combustion chamber and is fixed to a rotation shaft of a motor supported to the cylinder head. The fan has fan blades. The fan blades define a widthwise center line in the axial direction of the rotation shaft. The center line is offset from the connecting portion and toward the push lever. The fan blades define widthwise edges in confrontation with the cylinder head. The widthwise edge is positioned in alignment with the connecting portion or offset therefrom toward the cylinder head.

Abstract: A combustion type power tool having an arrangement avoiding direct striking of a drive shaft against a cylinder head when combustion pressure is exerted. A motor is disposed at the cylinder head and includes a motor body and a drive shaft extending in an axial direction and protruding into a combustion chamber. A fan is connected to the drive shaft to be rotatable within the combustion chamber. A buffer piece made from an elastic material is supported to the cylinder head. The buffer piece is movable relative to the cylinder head in a direction substantially perpendicular to the axial direction. The buffer piece is formed with a through-hole through which the drive shaft extends.

Abstract: A combustion-type power tool includes a cylinder and a combustion chamber frame disposed to surround the cylinder and movable along the cylinder. A partition wall divides an inner space of an outer frame into a first space in which the cylinder and the combustion chamber frame are disposed and a second space in which a gas cartridge cylinder is disposed and has a through-hole through which the first space and the second space are in fluid communication with each other. A plurality of ribs is formed on an outer surface of the cylinder for regulating an exhaust gas flow generated by combustion of a gaseous mixture in the combustion chamber. The ribs enable exhaust gas discharged from the combustion chamber to be directed away from the through-hole, thereby enabling the gas cartridge cylinder to be maintained at a substantially constant temperature.

Abstract: The present invention provides a dust collection unit usable with an electric tool having an electric motor, an end tool driven by the electric motor, and a cover partially covering the end tool and having a residue discharge port. The dust collection unit is detachably communicable with the residue discharge port. The dust collection unit has a main casing, lid means, and a handle. The main casing is configured to accommodate dust and residues therein. The main casing has an opening. The lid means opens and closes the opening. The handle is provided in proximity to the lid means on the main casing.

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: A compact and light-weight portable electric router produced at a low cost and capable of providing high cutting efficiency with low noise. A radial fan includes a cylindrical hub functioning as an attachment portion to a motor shaft, a plurality of fan blades having parts connecting to the hub, and a ring like guide section connected to the hub through the fan blades. An annular weight is connected to the guide section at a radially outer side of the guide section. The weight serves as a restriction section for restricting backflow of air from a discharge side to a motor side.

Abstract: A power tool includes a brushless motor, a cooling fan, and a driving unit in a housing. The brushless motor is provided in the housing and having a rotary shaft. The cooling fan is attached to the rotary shaft in the housing, and rotatable together with the rotary shaft. The driving unit is provided in the housing for driving the motor. The driving unit includes an inverter circuit having a circuit board and a plurality of switching elements mounted on the circuit board. The circuit board is positioned on an opposite side to the motor with respect to the cooling fan. The plurality of switching elements is positioned around the cooling fan in a circumferential direction about the rotary shaft.

Abstract: A combustion-type power tool having a cooling arrangement for cooling a gas canister. The tool includes a housing having a gas canister accommodating section in which a gas canister is accommodated. An air passage is defined between the gas canister accommodating section and the gas canister accommodated therein. The gas canister accommodating section is formed with an air inlet port in communication with the air passage for introducing air into the air passage. Since air flows along the gas canister, the gas canister can be cooled. If the tool is provided with a fan, the rotation of the fan causes air suction passing through the air passage.

Abstract: A combustion-type nail driver uses a motor for driving a fan. A motor holder formed from plastic accommodates the motor. A cylinder head has a motor holder receiving portion in which the motor holder is slidably movably disposed. A coil spring has one end secured to the motor holder and another end secured to the cylinder head to thereby support the motor holder. Initial acceleration applied to the motor when combustion occurs can be suppressed and impact imparted upon the motor can also be suppressed by friction between the outer periphery of the motor holder and the inner periphery of the motor holder receiving portion. A heat shielding plate is interposed between the lower end surface of the motor and the cylinder head in order to prevent hot air combustion gas from entering into the motor.

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-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: A compact battery pack with high handling ability and restraining degradation of battery cells. The battery pack includes an insertion portion to be inserted into a handle portion of a cordless power tool and an accommodation portion in which all battery cells are accommodatable. A protection board with a protection circuit that protects batteries against overcharge and over-discharge is installed in the insertion portion. A switching element is connected between the battery cells and a drive motor of the power tool. An air passage in communication with the battery pack is formed within the handle and a main housing of the cordless power tool. The switching element is positioned at the air passage.

Abstract: Fanned air generated by a fan to cool a motor is discharged from a housing through fanned air discharge ports toward an opening formed in a base. The fanned air discharged toward the opening is then introduced into a groove in fluid communication with the opening. The groove is formed in a bottom surface of the base and has an open side at a front side of the base. The fanned air is then discharged from the front side of the base, blowing off saw dust on a cutting object so as to prevent dust from accumulating on a marking line on the cutting object.

Abstract: A spark is shot between an ignition point of an ignition plug and an ignition ground. The spark is shot from an acute corner of a core of the ignition plug. A tip end of the core has an acute angle of not more than 45 degrees. With this arrangement, an emitting point of the spark can be concentrated to the tip end of the core. In order to reduce a thermal capacity of the ignition ground so as to enhance ignitability, a side opposite to the spark seating face of the ignition ground is tapered to provide an angle. Further, the ignition ground has an apex end providing an angle which is not more than 45 degrees. Because of the apex portion, thermal capacity of the ignition ground can be reduced and an acute angle can be realized to concentrate spark receiving point at the apex portion. As a result, ignitability can be enhanced.

Abstract: In the combustion-type power tool, a first shelter wall and a second shelter wall are disposed to partially surround an area between an ignition plug and an ignition ground. Two gaps are provided between the first and second shelter walls. The first shelter wall extends radially outwardly from an outer peripheral surface of a motor boss, and also protrudes from an end face in an axial direction of a fan shaft. The first shelter wall has a lower end surface inclined such that an axial length between the end face and the lower end surface is gradually reduced toward radially outer end of the first shelter wall.