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US 4,478,538 AGranted
Device for detecting tool abnormality
AssigneesYoshiaki Kakino, NF Circuit Design Block Co., Ltd., Showa Tool Co., Ltd.
InventorYoshiaki Kakino
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Abstract
When a drill is overloaded, while cutting a hole in a workpiece, a torque limiter disconnects the drill from a main spindle. As the drill is disconnected from the main spindle, the torque limiter generates high-level elastic waves. The elastic waves are converted by a transducer into a voltage signal. The level of the voltage signal is compared with a threshold value.
Claims7
A device for detecting tool abnormality, comprising:
- coupling means coupled between a tool holder and a rotatable main spindle for normally transmitting rotation of the main spindle to the tool holder, and for repeatedly stopping the transmission of rotation of the main spindle to the tool holder only when a tool abnormality exists, thereby generating elastic waves of a predetermined level;
- a transducer for converting the elastic waves into an electrical signal;
- and
- an amplitude discriminator for generating an output signal when the output signal from the transducer surpasses a threshold value.
1 more element
Dependencies are inferred from the claim text.