System for discharge of bulk materials from vehicles

A system for a discharge of bulk materials from a vehicle, said vehicle having at least one storage compartment with at least one discharge opening and a door covering said at least one discharge opening, held shut by an over-center action of a door operating mechanism having an articulated linkage, said door operating mechanism further including a first lever means for opening said door, and a second lever means for closing said door, a first cam means cooperable with said first lever means to open said door and a second cam means cooperable with said second lever means for closing said door, said first cam means and said second cam means being separate from said vehicle and each having means for moving said respective cam means between a first inoperative position and a second operative position and vice versa, so that in said second position said first cam means or said second cam means is in a position for contacting said first lever means or said second lever means, respectively, as the case may be, so that relative movement of said vehicle and said respective cam means opens or closes said door, and in said first position is retracted and unable to contact said respective levers;

• and, trip means attached to said each of said means for moving respective said first cram means and said second cam means operative for returning respective said first cam means and said second cam means to, and lock in, said first position whenever movement of respective said first cam means and said second cam means under loading in a direction of said first position exceeds a predetermined value.