A pneumatic drop frame trailer movable between a raised travel position and a lowered loading position, comprising:
- a frame having laterally opposed longitudinal sides, a front end, a rear end, and a top end;
- a generally flat deck having laterally opposed longitudinal sides, a front end and a rear end secured to said frame top end having a rear portion, a center ramp portion disposed at a rear portion of said deck between and a distance inwardly from said laterally opposed longitudinal sides, said ramp portion extending angularly downward and rearward terminating in a bottom end substantially even with a bottom surface of said frame rear end;
- a tongue pivotally connected at a rearward end to said front end and having a hitch at a forward end for connecting said trailer with a tow vehicle;
- first and second wheel support arms each having a forward end pivotally connected to a respective said longitudinal side of said frame;
- first and second ground-engaging wheel assemblies each rotatably mounted on a rearward end of a respective one of said first and second wheel support arms;
- first and second airbags each disposed between a respective one of said wheel support arms and said frame for pivoting said wheel support arms and their associated wheel assemblies relative to said frame;
- a third airbag disposed between said tongue and said frame forward end for pivoting said tongue relative to said frame between a horizontal towing position and a loading and unloading position disposed angularly between said frame and said tow vehicle;
- a source of air supply including an air compressor, an air storage tank and associated pneumatic control means on said frame operatively connected with each of said airbags for selectively inflating and deflating said first and second airbags simultaneously or independently to raise and lower said frame relative to the ground surface and selectively inflating and deflating said third bag independently of, or simultaneously with, said first and second airbags for pivoting said tongue relative to said frame between said horizontal towing position and said angularly disposed loading and unloading position while connected with said tow vehicle;
- wherein
- deflation of said first and second airbags simultaneously with said third airbag pivots said rearward end of said respective wheel support arm and associated wheel assembly to a raised position relative to said frame and said third airbag pivots said tongue angularly between said frame and said tow vehicle such that said frame is lowered evenly in a horizontal position, and said bottom surface of said frame is supported substantially horizontally on the ground surface in said loading and unloading position with said bottom end of said ramp portion of said deck substantially flush with the ground surface to facilitate moving items onto and off of said deck;
- inflation of said first and second airbags simultaneously with said third airbag pivots said rearward end of said respective wheel support arm and associated wheel assembly to a lowered position relative to said frame and said third airbag pivots said tongue to a horizontal position such that said frame is raised evenly in a horizontal position and supported horizontally above the ground surface in said towing position;
- and
- air pressure in said first and second airbags is selectively adjusted independently to provide stiffness and shock absorbing characteristics for absorbing road shocks as said trailer is towed.