Autoamtic tool-changing mechanism for multi-purpose working machine

The utility model relates to an automatic knife changing mechanism for integrated processing machines. A large bevel gear is driven to rotate mainly by a speed reducing motor of the knife changing mechanism to drive a roller gear cam and a knife loosening cam on a center shaft lever. A cam groove on an inner channel of the annular edge of the roller gear cam is used for interlocking a dividing roller piece of a needle bearing to rotate a rotating shaft of the dividing roller piece of the needle bearing and a driving piece on the upper end of the dividing roller piece of the needle bearing to drive the axle center of a knife holding arm simultaneously. When the shaft lever is rotated, a second roller in the cam groove of the inner channel of the large bevel gear is affected by the stroke change of the cam groove of the inner channel to enable an upper and a lower rocking arms to move, enable a first roller to drive an I-shaped sleeve barrel simultaneously and enable the axle center of the knife holding arm to carry out actions for changing and taking knifes up and down. When the knife changing mechanism is used for changing and taking knifes, the center shaft level of the knife changing mechanism drives the knife loosening cam to rotate. A knife loosening and pulling rocking arm which is abutted on one end of the knife loosening cam can be moved up and down along with the arc line change of the periphery of the knife loosening cam. The knife loosening and pulling rocking arm is pivoted on one end of a knife loosening pressing plate to drive an inner draw rod of a CNC main shaft to move up and down to control the state of clamping a knife handle by the CNC main shaft.