A mechanical plate shifter system for moving filter plates in a filter press during a process of plate separation for filter cake removal comprises: a pusher to automatically engage with a single filter plate at the end of a stack or at the edge of a gap in the stack for moving the plate forward and then automatically disengaging when the plate reaches an end plate/dummy plate or another filter plate previously pushed. The filter plates are configured with handles for engaging with the pusher. The pusher is attached to a continuous drive belt and is configured with a pivoting structure including: a head with a receiving notch for a handle of a filter plate; and a counterweight for the head. The pusher and belt are configured relative to the filter plate stack to allow for filter plates to be engaged/disengaged by the receiving notch.