Vertical machine tool and tool changing method

A vertical machine tool, comprising:

• a frame;
• a spindle having a spindle hole configured to mount a tool;
• a spindle mover installed on the frame, the spindle mover configured to move the spindle with respect to the frame;
• a magazine including:
• a rotatable magazine disc having a plurality of pot holding holes, and
• a plurality of pots, each of the plurality of pots being configured to house a respective tool therein and each of the plurality of pots being received within a respective one of the plurality of pot holding holes, wherein each of the plurality of pots is configured to be moved up and down between an elevated position and a changing position;
• a pot lifter installed on the frame, the pot lifter configured to move up and down from the changing position to the elevated position a given pot of the plurality of pots that is located at a pot tool changing position;
• a linear motion guide installed on the frame;
• an intermediate arm assembly installed on the linear motion guide, the intermediate arm assembly including:
• an arm including a first gripper and a second gripper, and
• an arm rotation device configured to position the first gripper or the second gripper to either a magazine phase position or a spindle phase position;
• and
• an intermediate arm feeder configured to move the intermediate arm assembly among a magazine position, a spindle position, and an intermediate position located between the magazine position and the spindle position, wherein
• the pot lifter has a hook member, and each of the plurality of pots has a respective top plate to which an associated knob is attached, and
• when the magazine disc is rotated about the axis of rotation so as to bring the given pot of the plurality of pots into the pot tool changing position, the knob of the given pot is received within the hook member such that the pot lifter catches the given pot, and
• when the pot lifter catches the given pot, the pot lifter is able to lift the given pot up into the elevated position such that the first gripper or the second gripper can move the tool associated with the given pot back and forth below the given pot without the first gripper or the second gripper causing the given pot to interfere with the associated tool.