A control mechanism for the feed of a brush chipper is disclosed. A lower feed stop bar, located under a feed table, pivots on a pivot axis located below and toward the brush chipper from the control bar of the lower feed stop bar. The center of gravity of the lower feed stop bar, then, tends to pivot the lower feed stop bar away from the feed disengage position. Hence, nuisance trips due to vibration, impact of brush on the table, etc., are reduced.