Abstract: If a voltage of an electricity storage unit of an electric tool is not greater than a first threshold voltage, the electricity storage unit is charged with a first constant trickle current until the voltage of the electricity storage unit is greater than the first threshold voltage. Then, the electricity storage unit is charged with a constant current until the voltage of the electricity storage unit is greater than or equal to a second threshold voltage. Then, the electricity storage unit is charged with a constant voltage until a current for charging the electricity storage unit is equal to a second constant trickle current, and then the electricity storage unit stops being charged. The electricity storage unit is float charged automatically when a transient voltage of the electricity storage unit is decreased and is less than or equal to a third threshold voltage.

Abstract: A method for a system to generate an item recommendation. The method includes determining, for each of a plurality of roles, a plurality of reference utility values each for one of a plurality of items, and performing a normalization on the plurality of reference utility values determined for each of the plurality of roles. The method further includes determining a plurality of aggregate utility values each for one of the plurality of items, based on a plurality of normalized reference utility values determined for each of the plurality of roles, and determining one or more combinations of items for recommendation based on the plurality of aggregate utility values.

Abstract: A power tool includes a tool housing provided with a set of first electrical contacts, an electric drive motor mounted in the tool housing and coupled electrically to the first electrical contacts, and a driver unit mounted in the tool housing and coupled to and driven rotatably by the electric drive motor. A power supply cartridge includes a casing connected removably to the tool housing, a set of second electrical contacts to connect electrically with the first electrical contacts when the casing is connected to the tool housing, and a power converter disposed in the casing and coupled electrically to the second electrical contacts. A power supply cable has a first end connected to the power supply cartridge to connect electrically with the power converter, and a second end adapted to be connected to an external power source.

Abstract: A tool holder includes at least one fixing seat mounted on a guide rail for horizontal sliding movement and provided with a slot hole for receiving stem tools of different sizes, with an elastic press sheet disposed within the hole for urging the tool against a rear wall portion to secure the tool in proper position. A hook is provided at a front portion of the fixing seat for supporting tools with holes, such as a box spanner. The holder may include a plurality of fixing seats disposed in a vertical array and horizontally offset from each other to facilitate the storage and access of a large number of tools.