US 12,468,061 B2
Electric tool
Kohei Suto, Tokyo (JP)
Assigned to Max Co., Ltd., Tokyo (JP)
Filed by MAX CO., LTD., Tokyo (JP)
Filed on Aug. 24, 2021, as Appl. No. 17/410,242.
Claims priority of application No. 2020-141771 (JP), filed on Aug. 25, 2020.
Prior Publication US 2022/0066062 A1, Mar. 3, 2022
Int. Cl. G01V 3/08 (2006.01); B23B 39/00 (2006.01); B25F 5/00 (2006.01)
CPC G01V 3/088 (2013.01) [B23B 39/00 (2013.01); B25F 5/00 (2013.01); B23B 2260/128 (2013.01)] 11 Claims
OG exemplary drawing
 
1. An electric tool comprising:
an output part configured to come into contact with a working target to process the working target;
a motor configured to drive the output part;
a gear configured to transmit a rotational force of the motor;
a metal case incorporating the gear inside the metal case; and
a self-capacitance sensor including one electrode and an electric wire extending from the electrode to the metal case, and configured to measure capacitance of a metal part including the output part in at least a part of the metal part,
wherein the self-capacitance sensor is electrically connected to the output part, which is at least the part of the metal part, via the electrode, the electric wire, the metal case and the gear, and
wherein the electric tool detects a foreign object based on a change in the capacitance of the metal part measured by the self-capacitance sensor.