| 摘要 |
A hand-held, battery powered tool (1) (e.g., nutrunner, drill) includes an output head (5) operatively connected to a motor (2), a plurality of battery cells (9), an ON/OFF start switch (7), a resistance sensor (4) that measures a resistance of the output head (5) to movement, and a controller (6). When the start switch (7) is ON and the resistance sensed by the resistance sensor (4) does not exceed a predetermined shift resistance, the controller (6) automatically connects the plurality of battery cells (9) to each other and the motor (2) in series. When the start switch (7) is ON and the resistance sensed by the resistance sensor (4) exceeds the predetermined shift resistance, the controller (6) automatically connects the plurality of battery cells (9) to each other in parallel and to the motor (2). |
