PURPOSE: To detect the opening width of a chuck device in the stationary state of a shaft in advance by forming a sensor for detecting the opening width of the chuck device in the stationary state of the electric motor of a power tool.
CONSTITUTION: Chuck pawls 8 are formed so that a support 7 is slid along a shaft 2 without play in the axial direction via a wedge-shaped inclined plane when a chuck device is opened or closed. A sensor 5 is stationarily arranged on a casing 9 in the moving space of the support 7 along the shaft 2. When the chuck pawls 8 are opened to an opening width forming the clamping width, a voltage UA is generated on the coil of the sensor 5, and the sensor 5 is formed so that the value of the voltage UA is changed in response to the insertion depth of a magnetic ring 6 into the sensor electromagnetic field.
YURIAN PUFUAUNDORAA
OTSUTOMARU ZEERU
BUORUFUGANGU HIRUSHIYUBURUGAA
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