Abstract: A chainsaw includes a chain tension mechanism. The chain tension mechanism includes: an adjustment dial made of resin and rotatable about an axis in a right-left direction; a rotation transmission member made of metal and rotatable about an axis in the right-left direction; a feed screw member made of metal and rotatable about an axis in a front-rear direction; and a slide member coupled to a guide bar. The slide member is screwed to the feed screw member. A first gear of the adjustment dial is meshed with a second gear of the rotation transmission member, and a first bevel gear of the rotation transmission member is meshed with a second bevel gear of the feed screw member.

Abstract: An engine-driven working machine includes a controller, which varies a control value of a solenoid valve so as to decrease or increase an opening degree of the solenoid valve when a rotating speed of an engine is within a predetermined high rotating speed range and the rotating speed of the engine is lower or higher than a predetermined rotating speed, respectively. When the control value of the solenoid valve is varied so as to decrease the opening degree of the solenoid valve and corresponds to a predetermined opening degree larger than a fully-closed state, the control value is set to a limitation value.

Abstract: An engine-driven working machine includes a controller, which varies a control value of a solenoid valve so as to decrease or increase an opening degree of the solenoid valve when a rotating speed of an engine is within a predetermined high rotating speed range and the rotating speed of the engine is lower or higher than a predetermined rotating speed, respectively. In case the controller determines that the engine-driven working machine gets started saw cutting, the controller stops varying the control value of the solenoid valve when the rotating speed of the engine is within the predetermined high rotating speed range and lower than the target rotating speed.

Abstract: A semiconductor device includes a first switching element, a pre-driver, a coil, a second switching element and a capacitor. The first switching element is connected between a power and a load driving circuit and includes a parasitic diode having cathode adjacent to the load driving circuit. The pre-driver drives the first switching element. The coil is connected between the power and the first switching element. The second switching element includes an output terminal connected to a first connection point between the power and the coil, an input terminal connected to a second connection point between the first switching element and the pre-driver, and a control terminal connected to ground. The capacitor has one end connected to a point between the first switching element and the load driving circuit and another end connected to ground. Even when power supply voltage decreases, the semiconductor device can restrict breakage of switching element.

Abstract: An engine-driven working machine includes a controller, which varies a control value of a solenoid valve so as to decrease or increase an opening degree of the solenoid valve when a rotating speed of an engine is within a predetermined high rotating speed range and the rotating speed of the engine is lower or higher than a predetermined rotating speed, respectively. When the control value of the solenoid valve is varied so as to decrease the opening degree of the solenoid valve and corresponds to a predetermined opening degree larger than a fully-closed state, the control value is set to a limitation value.

Abstract: An engine-driven working machine includes a controller, which varies a control value of a solenoid valve so as to decrease or increase an opening degree of the solenoid valve when a rotating speed of an engine is within a predetermined high rotating speed range and the rotating speed of the engine is lower or higher than a predetermined rotating speed, respectively. In case the controller determines that the engine-driven working machine gets started saw cutting, the controller stops varying the control value of the solenoid valve when the rotating speed of the engine is within the predetermined high rotating speed range and lower than the target rotating speed.

Abstract: A semiconductor device includes a first switching element, a pre-driver, a coil, a second switching element and a capacitor. The first switching element is connected between a power and a load driving circuit and includes a parasitic diode having cathode adjacent to the load driving circuit. The pre-driver drives the first switching element. The coil is connected between the power and the first switching element. The second switching element includes an output terminal connected to a first connection point between the power and the coil, an input terminal connected to a second connection point between the first switching element and the pre-driver, and a control terminal connected to ground. The capacitor has one end connected to a point between the first switching element and the load driving circuit and another end connected to ground. Even when power supply voltage decreases, the semiconductor device can restrict breakage of switching element.

Abstract: A portable engine-driven working machine has an engine unit and a cover enclosing the engine unit. The engine unit includes a cylinder block, an electronically controlled carburetor, a controller connected to the carburetor and a diagnostic connector connected to the controller. The cover has a cylinder cover partially defining a first chamber containing the cylinder block and partially defining a passage for air which cools the cylinder block, and a removable connector cover partially defining a second chamber containing the diagnostic connector.

Abstract: An ECU attached to a motor assembly has a substrate and a heat sink. The substrate mounts thereon a microcomputer, which controls driving of a motor in accordance with a rotation angle of the motor. The substrate is fixed to the heat sink. The substrate has a first through hole group and a second through hole group, which are through holes connectable electrically by soldering to rotation angle signal wires connected to a rotation angle sensor, which detects a rotation angle of the motor.

Abstract: An ECU attached to a motor assembly has a substrate and a heat sink. The substrate mounts thereon a microcomputer, which controls driving of a motor in accordance with a rotation angle of the motor. The substrate is fixed to the heat sink. The substrate has a first through hole group and a second through hole group, which are through holes connectable electrically by soldering to rotation angle signal wires connected to a rotation angle sensor, which detects a rotation angle of the motor.

Abstract: A part positioner according to the present invention is used for fixing a part having a first pair of opposite portions extending along a mounting surface to the mounting surface by use of a clamping fixture. The part positioner includes a pressing member for pressing the part against the mounting surface with a clamping force of the clamping fixture. The pressing member includes a pressing portion (tapered projection) for pressing the first pair of opposite portions in opposite directions in a position apart from the clamping fixture, owing to a clamping operation of the clamping fixture.

Abstract: The present invention provides nonvolatile semiconductor memory devices which operate with low power consumption. In a nonvolatile semiconductor memory device, a plurality of nonvolatile memory elements are connected in series. The plurality of nonvolatile memory elements include a semiconductor layer including a channel forming region and a control gate provided to overlap with the channel forming region. Operations of write, erase, a first read, and a second read in a verify operation of data to the nonvolatile memory elements, are conducted by changing voltage to the control gates of the nonvolatile memory elements. The second read in the verify operation after erase operation is conducted by changing only one of a potential of the control gate of a nonvolatile memory element which are selected from the plurality of nonvolatile memory elements, and as the potential, a potential different from a potential of the first read is used.

Abstract: A part positioner according to the present invention is used for fixing a part having a first pair of opposite portions extending along a mounting surface to the mounting surface by use of a clamping fixture. The part positioner includes a pressing member for pressing the part against the mounting surface with a clamping force of the clamping fixture. The pressing member includes a pressing portion (tapered projection) for pressing the first pair of opposite portions in opposite directions in a position apart from the clamping fixture, owing to a clamping operation of the clamping fixture.

Abstract: A brake system of a working machine includes a brake connector for operatively connecting between a brake lever and a braking member, and an urging member that maintains the brake lever at a predetermined neutral position and also acts to return the brake lever to the predetermined neutral position when the brake lever is displaced from the predetermined neutral position. When the brake lever is located at the predetermined neutral position, the brake lever and the brake connector are out of contact with each other.