1. Field of the Invention
The present invention is directed to an improvement in a tool changing or transport mechanism for a machine tool which mechanism enables changing the tool in the spindle of the machine tool with tools which are normally carried in an adjacent storage structure.
2. Prior Art
In U.S. Pat. No. 3,999,664, a tool changer with a dual axis of rotation is described, and this tool changer had many advantages over the tool changer disclosed in U.S. Pat. No. 3,760,490. The dual axis tool changing mechanism had a transfer arm, which is rotatable on a first axis and enables moving a tool from a spindle of a machine tool to a pocket in a magazine of a storage device. In order to enable inserting the tool in the pocket and also into the spindle, the transfer arm rotates the tool about a second axis which extends along the length of the arm. Thus, during transfer the tool is turned end for end.
While this device has proven extremely satisfactory in many machine tools, problems may occur when the machine tool has an increased size so that the distance between the operating axis defined by the spindle and the storage axis increases. For example, if the length of the transfer arm is increased to enable transferring the tool over a greater distance, the arc of the path of movement of the tool is increased and in some instances, increases problems concerning providing sufficient clearance for movement of the tool during a tool transfer operation.