Machine tool with automatic tool change function

In a machine tool with an automatic tool change function having a tool spindle rotatably supported and capable of receiving a tool at one end thereof, the improvement comprising:

• a key fixedly mounted on one end of said tool spindle;
• a key-way formed on said tool;
• tool support means for rotatably supporting at least one tool to selectively insert and remove said at least one tool into and from said tool spindle;
• control means responsive to a tool change command for rotating said tool spindle at a predetermined speed suitable for the engagement of said key with said key-way;
• operating means for causing relative movement between said tool support means and said tool spindle in an axial direction of said tool spindle for a tool change operation with said tool spindle being rotated at the predetermined speed;
• stopping means operable against said operating means for stopping said relative movement between said tool support means and said tool spindle at a predetermined position in the axial direction of said tool spindle before said key comes into engagement with said key-way, said operating means being urged to further cause said relative movement while said stopping means is in operation;
• first detecting means for detecting a first predetermined angular position of said key relative to said key-way to thereby generate a first signal;
• and
• releasing means responsive to said first signal for deactivating said stopping means so as to thereby permit said operating means to further cause said relative movement between said tool support means and said tool spindle.