#$%^&*AU2015213369A120170302.pdf#####ABSTRACT In one aspect there is disclosed a plough that includes a support frame, a plurality of gangs of discs, two or more wheel assemblies, a drive systems that rotates the gangs about respective vertical axes and a lock system. The lock system retains each gang at a selected angle of rotation relative to a longitudinal axis of the support frame. The system comprises a first lock that intersects the rotational path of the gang to counteract rotational torque on the gang caused by drag during operation of the plough and a second lock that is independent from the first lock and which secures the gang at the selected angle of rotation and is free of the rotational path of the gang. Another aspect discloses a locking system for retaining gangs of discs at a selected angle of rotation. A further aspect disclosed is a method of operating a locking system. 6797189_1 (GHMatters) P100615.AU LEANNE 13/08/15Figure 5 zUKOCrm P1065 AU NMcym ~rsi
