member being fixedly secured to the bed frame member 22 and extending to the rear end thereof the rear end of bed frame members 22 may be beveled as seen at 36 the front portion of the dump bed preferably is supported by the vehicle frame at supports 38 carried by vehicle frame members 18 when the bed is in transport position illustrated in fig1 the front of the dump bed 20 is connected to the vehicle frame 12 by folding support means 40 at each side thereof each folding support means 40 includes an elongated rigid arm 42 of l shape characterized by an angularly extending part 44 at the end thereof which is lowermost in the dumping position illustrated in fig2 the opposite end of each arm 42 is pivoted at 46 to a bed frame member 22 the end of the angularly extending part 44 of arm 42 is pivotally connected at 48 to the end of a rigid elongated arm 50 whose opposite end is pivoted at 52 to a vehicle frame member 18 power driven actuating means for elevating and lowering the dump bed preferably comprise a pair of similar double acting hydraulic extensible members at opposite sides of the vehicle each actuating member includes a cylinder 54 within which is shiftable a piston not shown connected to an extensible and retractable piston rod 56 projecting from one end of the cylinder the power members are interconnected for conjoint.