Auto tools change with space allowance for tool rejection of spindle

An auto tools changer with a space allowance for enabling a draw rod of a spindle to move during tool ejection, comprising:

• an arm seat, with an arm shaft installed therein that is capable of rotating about an axis and axially sliding along said axis, wherein one end of the arm shaft extends outward from the arm seat and is connected to a tool change arm;
• a flat cam that is disposed in the arm seat and is rotatably driven by a rotation axle, wherein the flat cam has a concave driving groove formed thereon, and the driving groove is provided with an inner wall and an outer wall between which a tool clamping section, a first transition section, a tool unclamping section, and a second transition section extend;
• and
• a driving arm having a swinging end, a driving end, and a projecting rolling member disposed there between, the rolling member is connected to the driving groove and is capable of moving within the driving groove, and the driving end is connected to the arm shaft thereby enabling the driving arm to axially slide the arm shaft along said axis via the driving groove during rotation of the flat cam,
• wherein an allowance groove is disposed on the outer wall in the tool clamping section of the driving groove, whereby the rolling member cannot simultaneously contact the inner wall and the outer wall of the driving groove when disposed within the allowance groove, as a larger width is offered between the inner wall and outer wall within the confines of the allowance groove as compared to a width offered between the inner wall and outer wall within the remainder of the driving groove, and an axial sliding space is thus produced for the rolling member as the space allowance for the draw rod of the spindle to move during tool ejection.