Abstract: A dump truck spreads material to form a layer of material to form a structure such as a road by tilting a dump body pivoted on the truck and allowing a tailgate to open a gap through which the material flows as the dump truck moves forward. Typically, a pair of chains determine the width of the gap. In order to release the chains and allow the tailgate to swing freely if the material becomes jammed and does not freely flow through the gap, a pair of toggle-type chain releases are provided. The toggle-type chain releases comprise chain-retaining plates with slots therein for receiving one link of the chains. The retaining plates are rotatable from a chain-retaining position to a chain-releasing position. The toggles which operate the chain retaining plates include levers which are unitary with one link of the toggles and serve as operating handles which when pulled releases the chains.

Abstract: A controllable tailgate compatible with conventional rearward tilting dump trucks is attached at its uppermost corners to the upper end of two rear corner truck bed posts and pivots from a closed position to an open position enabling the discharge of material through an opening between the bottom of the tailgate and outer edge of the truck bed. The dump truck can be manufactured to accommodate the controllable tailgate or the truck bed can be modified by adding both a truck bed floor and two truck bed side-extension panels to match the truck bed to the tailgate. One or more movable gates are connected to the lower exterior of the tailgate across its width and are controllable from within the cab of the dump truck. The gates are moved to close the opening between the tailgate and truck bed when the dump truck is tilted rearward and the tailgate is in an open, unloading configuration. The gates serve to control the discharge of material from the dump truck.