Patent ID: 8827608

Claim:
A tool tight-contact-state detector for a machine tool, characterized by comprising: a main spindle which is supported rotatably by a main spindle head and has a seating face on which any one of a tool for performing a certain machining on a machining target and a tool holder having the tool attached thereto is to be detachably mounted; a cylinder section which is formed in the main spindle head and in which a piston member is housed slidably; elastic means for biasing the piston member; fluid supplying means for supplying fluid to the cylinder section, thereby bringing the piston member into contact with the main spindle head and the main spindle against a biasing force from the elastic means, while rotation of the main spindle is stopped; gas supplying means for supplying gas to the main spindle from the main spindle head through the piston member, when the fluid supplying means supplies the fluid to the cylinder section thereby bringing the piston member into contact with the main spindle head and the main spindle against the biasing force from the elastic means; a plurality of gas ejection holes which are formed in the seating face and eject the gas supplied from the gas supplying means; and tool tight-contact-state judging means for judging whether or not the any one of the tool and the tool holder is in tight contact with the seating face by detecting a gas pressure of the gas ejected from the gas ejection holes when the any one of the tool and the tool holder is mounted to the seating face.