Abstract: A method for operating a disc-type log chipping machine includes controlling the proper position of a log with respect the chipping mechanism of the machine as the log is being reduced by the chipping mechanism. The method includes moving the upper feed assembly with respect to the frame between an engagement position in which the upper feed assembly contacts the log to advance it towards the chipping mechanism and a raised position in which the upper feed assembly is above and out of contact with the log. The method operates to move the upper feed assembly from the engagement position to the raised position intermittently in order to orient the log axis in a generally parallel relationship with the long axis of the frame as the log is being reduced.

Abstract: A log chipping machine includes a frame having a long axis and a rotating chipping mechanism having an axis of rotation that is oblique to the long axis of the frame of the machine. The machine also includes a log advance system that is adapted to advance a log to the chipping mechanism, in a processing direction that is generally parallel to the long axis of the frame. The log advance system includes an upper feed assembly. A control system includes a lifting assembly and a controller assembly. The lifting assembly is adapted to move the upper feed assembly with respect to the frame between an engagement position in which the upper feed assembly contacts the log to advance it towards the chipping mechanism and a raised position in which the upper feed assembly is above and out of contact with the log.