Patent ID: 9599738
Date: 2017-03-21
CPC Classifications: B21D,G01V

Claim:
1. A tool position detection device comprising: a power feeding electrode provided on an inner wall of a tool attachment that attaches thereonto a tool having a power receiving electrode and a displacement electrode, the power feeding electrode being provided to be opposite to the power receiving electrode in a longitudinal direction of the tool attachment in a non-contact state; a plurality of detection electrodes provided on the inner wall to be opposite to the displacement electrode in a non-contact state, being insulated from the power feeding electrode, and being provided in line in the longitudinal direction of the tool attachment; and a power supply configured to supply an alternating current power feeding signal to the power feeding electrode, wherein, when the tool is attached onto the tool attachment, a pair of the power feeding electrode and the power receiving electrode, which are provided opposite to each other, and a pair of a detection electrode and the displacement electrode, which are provided opposite to each other, form a capacitor circuit, a capacity of the capacitor circuit is configured to be changed in response to a position of the tool with respect to the longitudinal direction of the tool attachment, and the tool position detection device further comprises: a voltage information extractor configured to extract voltage information from the detection electrode when the power feeding signal is supplied to the power feeding electrode by the power supply, the voltage information being changed in response to the capacity of the capacitor circuit; and a position detection/arithmetic operation unit configured to detect to which position in the longitudinal direction of the tool attachment the tool is attached based on the voltage information extracted by the voltage information extractor.