Abstract: A power tool is provided such that noise can be reduced at a wide range of rotation speeds. A speed setting dial to be operated by a worker is disposed on a rear end part of a housing of a grinder. A control part controls driving of a motor by setting the rotation speed of the motor in response to the value of a speed setting signal which indicates a value (voltage) corresponding to an amount of rotation of the speed setting dial by the worker. Although the control part basically causes the rotation speed of the motor to change continuously in response to the rotation amount of the speed setting dial, the control part sets the rotation speed of the motor while avoiding a predetermined rotation speed region in which the noise level is increased due to mechanical and acoustic resonances.

Abstract: A power tool includes: a brushless motor; a rectifier circuit; a smoothing circuit; an inverter; a controller; an operating part; and a switch. The switch is rendered ON in accordance with an operation performed in the operating part by a user to allow power to be supplied to the inverter circuit by the rectifier circuit through the smoothing circuit and rendered OFF in accordance with release of the operation by the user to interrupt the inverter circuit from the rectifier circuit to halt supplying the power to the inverter circuit. The smoothing circuit includes a first capacitor and a second capacitor connected in parallel. The controller is configured to control the switching operations of the inverter circuit to drive the brushless motor in accordance with a signal inputted in accordance with the operation performed in the operating part by the user.

Abstract: In order to provide an electric tool such that the capacitances of noise-suppressing film capacitors can be increased without increasing the diameter of a handle section, the housing of the electric tool comprises: a body section that stores a brushless motor, a striking mechanism part, and a portion of an output part; a handle section, whose one end is connected to the body section; and a storage section that is formed on the other end of the handle section. A pair of film capacitors for removing noise generated from an inverter circuit are mounted on a capacitor substrate and stored side by side inside the handle section. The film capacitors are connected in parallel with each other, thereby providing a capacitor having a larger total capacitance than before.

Abstract: A backpack-type power supply includes: a plurality of cell units (52) each configured of a plurality of secondary battery cell (51); a case (12) configured to accommodate the cell units and having first and second contacts; and a harness (13) attached to the case, characterized by including; first connecting means (581, 571) for electrically connecting the first contact and a positive terminal of each cell unit to form a first electrical path therebetween; and second connecting means (572, 582) for electrically connecting the second contact and a negative terminal of each cell unit to form a second electrical path therebetween, each first electrical path and each second electrical path forming a total electrical path having a total resistance for each cell unit, the total resistance of each total electrical path being adjusted such that heat distribution is substantially uniform over the plurality of cell units in the case.

Abstract: An electrical power tool capable of suppressing increase in a size of a device main body in a radial direction of an electrical motor is provided. A driver which drives a distal end tool with a power of an electrical motor includes: a casing in which the electrical motor is provided; a driven gear and a spindle which are arranged eccentrically with respect to an output shaft of the electrical motor and which transmit power of the output shaft to the distal end tool; and a power supply circuit unit arranged inside the casing. And, an arrangement region of the driven gear and the spindle and an arrangement region of the power supply circuit unit are at least partially overlapped with each other in a circumferential direction centering the output shaft.

Abstract: The backpack-type power supply includes a rechargeable battery, a case, a harness, and an operation unit. The case accommodates the rechargeable battery. A user wears the case on a back of the user by the harness. The operation unit includes at least one of a switch and a display unit. The switch is configured to enable or disable the rechargeable battery. The display unit is configured to display a battery level of the rechargeable battery.

Abstract: A backpack-type power supply includes: a plurality of cell units (52) each configured of a plurality of secondary battery cell (51); a case (12) configured to accommodate the cell units and having first and second contacts; and a harness (13) attached to the case, characterized by including; first connecting means (581, 571) for electrically connecting the first contact and a positive terminal of each cell unit to form a first electrical path therebetween; and second connecting means (572, 582) for electrically connecting the second contact and a negative terminal of each cell unit to form a second electrical path therebetween, each first electrical path and each second electrical path forming a total electrical path having a total resistance for each cell unit, the total resistance of each total electrical path being adjusted such that heat distribution is substantially uniform over the plurality of cell units in the case.

Abstract: A backpack-type power supply includes a rechargeable battery, a case, and a harness. The case accommodates the rechargeable battery. The case has a surface. By the harness, a user wears the case on a back of the user with the surface facing the back. The surface is formed with a recession and a protrusion.

Abstract: In a backpack-type power supply, a case accommodates the rechargeable battery. An output terminal is electrically connected to the rechargeable battery. A switching element is electrically connected between the rechargeable battery and the output terminal. A main power switch is electrically connected between the rechargeable battery and the switching element. The processing unit is electrically connected between the switching element and the main power switch to be powered by the rechargeable battery when the main power switch is ON.

Abstract: A rechargeable system includes: a charger (4); a battery pack (1); an adapter (3) configured to be electrically connected between the charger (4) and the battery pack (1), a cable (58) configured to be electrically connected between the battery pack (1) and the adapter. A battery-side microcomputer (526) controls the shutdown circuit (523) such that the shutdown circuit (523) disconnects the at least one of the positive terminal (5a) of the battery pack and the negative terminal (5b) of the battery pack (1) from the rechargeable battery (51) when detection of the battery-side microcomputer (526) indicates occurrence of at least one of two following events: one event is such that the rechargeable battery (51) is fully charged. Another event is such that the rechargeable battery (51) has some errors.

Abstract: The backpack-type power supply includes a rechargeable battery, a case, a harness, and an operation unit. The case accommodates the rechargeable battery. A user wears the case on a back of the user by the harness. The operation unit includes at least one of a switch and a display unit. The switch is configured to enable or disable the rechargeable battery. The display unit is configured to display a battery level of the rechargeable battery.