Machine tool with a spindle head

A machine tool which provides uninterrupted coolant flow to a tool, comprising:

• a spindle head movable between a vertical and a horizontal working position;
• a tool spindle rotatably mounted in said spindle head and provided with a toolholder having a coolant passage communicating with the tool;
• a clamping means mounted in said spindle for selectively clamping and release the tool, said clamping means having inner end portions which are engageable during releasing of the tool;
• an axially movable tension rod having opposed axial ends, and means for axially moving said rod so that one axial end thereof is adapted to engage said inner end portion of said clamping means to cause said clamping means to release the tool, said tension rod having a coolant bore extending axially therethrough, said coolant bore having a sealing means at an open end opposite said one axial end of said tension rod;
• and
• a transfer piston, and means for moving said transfer piston axially relative to said tension rod to selectively contact the other axial end of said tension rod to transfer axial movement to said tension rod, said transfer piston surrounding a coolant supply line communicating with said coolant bore in said tension rod and having sealing means in sealing engagement with said coolant bore sealing means, said transfer piston being axially movable with respect to said coolant supply line whereby said respective sealing means maintain said coolant bore and said coolant supply line in constant communication so that coolant can be flowed uninterrupted through said coolant supply line, said coolant bore and said coolant passage to the tool irrespective of the axial position of said transfer piston.