Rotary-magazine tool changer capable of changing tool storage position

A tool changer for a machine tool, comprising:

• a rotary tool magazine configured to attach and detach tools to and from a spindle of the machine tool, the tools comprising a first tool and a second tool to be mounted on the spindle after the first tool, the rotary tool magazine including tool storage positions at least including a first, a second and a third tool storage positions;
• tool grip portions circumferentially disposed on the tool magazine corresponding to the tool storage positions;
• an index unit configured to turn the tool magazine while one of the tools is mounted on the spindle;
• and a control unit configured to control the index unit, during a tool change operation,
• wherein
• the first tool was stored at the first tool storage position before being mounted to the spindle, and the third tool storage position is empty during the entire time that the first tool is mounted on the spindle,
• the tool changer comprises a command unit for outputting, to the control unit a change command for changing a tool storage position for the first tool from the first tool storage position where the first tool was stored before being mounted on the spindle to the third tool storage position where the first tool is to be stored after being removed from the spindle, wherein the third tool storage position is closer to the second tool storage position where the second tool is stored than to the first tool storage position,
• the index unit is configured to rotate the tool magazine even when the first tool is mounted on the spindle, and
• the control unit is configured to
• on receiving the change command from the command unit, turn the tool magazine while the first tool is mounted on the spindle, and control the index unit to index the tool grip portion corresponding to the third tool storage position to a tool change position to store the first tool mounted on the spindle into the third tool storage position, then
• control the index unit to index the second tool storage position stored with the second tool to the tool change position to mount the second tool on the spindle after the first tool.