Trailer with adjustable wheels

A load carrying machine comprising structure of substantially rectangular outline having a front end and a back end for receiving and supporting a load, a plurality of wheels comprising at least two sets of wheels, each set comprising at least four wheels arranged as two tandem pairs, the pairs of each set being axially spaced transversely of said machine, one set of which is adjacent the front end and one set of which is adjacent the rear end of said load supporting structure, the wheels of each tandem pair being respectively adjacent opposite sides of said structure, said front set of wheels being mounted from said machine for pivoting about a substantially vertical axis, means interconnecting said wheels and said structure for moving axially spaced tandem pairs of said wheels of each set toward and away from one another axially of such wheels, and means for moving all of said wheels up and down relative to said supporting structure to vary the height of said supporting structure, the underside of said structure adjacent the front thereof being substantially flat to permit said front set of wheels to pivot with said wheels in axially extended relation, the wheels of each tandem pair respectively being mounted on tandem pairs of pivot arms, each tandem pair of pivot arms being pivoted on a common member, each such member being mounted from said structure for rocking about a respective axis transverse of said machine, said pivot arms being pivoted on said member relatively adjacent the upper portion of said member and diverging downwardly therefrom respectively in fore and aft directions, and wherein the means for moving up-and-down comprises means acting between pairs of pivot arms to effect pivoting thereof to raise or lower the wheels relative to said supporting structure, said arms having portions thereof abuttable with lower portions of a respective common member to serve as stops for said arms to limit lowering of said wheels.