Bottom dump trailer

A bottom dump trailer comprising a trailer frame, ground wheels for transportation of the frame across the ground, a hopper mounted on the frame for transportation of a pourable solid material including hopper sidewalls converging downwardly and inwardly to an open bottom of the hopper for discharge of the material through the open bottom, a door for opening and closing the open bottom including a door surface and means mounting the door surface suspended from the frame so as to be pivotal about an axis of movement offset from the door surface to one side thereof and arranged above said open bottom, the door thus being pivotally movable from a first position, in which the door surface lies across an underside of the open bottom with a front edge of the door surface in contact with a closure member at a line of contact which is below the open bottom to a second position in which an opening is formed between said front edge and said closure member, drive means for moving said door outwardly from the first position toward one of two opposed sides of the hopper, and means for halting said movement at a required position, said halting means comprising an abutment member, mounting means mounting said abutment member on a frame member adjacent a respective one of said opposed sides of the hopper, said door having abutment means thereon for engaging said abutment member and movable in a path of movement as said door moves from the first position to the second position, said mounting means including means defining a plurality of selectable locations for the abutment member for engaging the abutment means at different points in its path of movement such that the amount of movement of the door from the first position can be adjusted for adjustment of the size of the opening and moving means for moving said mounting means such that the abutment member is moved out of the path of travel of the abutment means to allow the door to be moved to a maximum open position.