Hoist for vehicle mounted box

Claim 2

A hoist mechanism for lifting a load-carrying box hinged for tilting movement on the chassis of a wheeled, dirigible automotive vehicle, said hoist comprising, in combination, a torsion bar extending transversely of the chassis at a point spaced from the hinge between the box and the chassis, means journaling said torsion bar for axial rotation with respect to said chassis, an obtuse-angled bellcrank connector means fixed at each end of said torsion bar outboard of said chassis and having first and second leg means extending therefrom and forming an obtuse angle with respect to each other, a jackknife hoist means fixedly secured to the first leg of each said bellcrank connector means and pivotally engaged with the underside of the loadcarrying box, and power means pivotally mounted between said hoist means and the second leg of said bellcrank connector means, each said hoist means and associated power means being mounted outboard of the vehicle chassis, said power means being actuable to jackknife said hoist means to lift said load-carrying box while applying a load-unbalance compensating torque to said torsion bar whereby lifting forces at each side of the loadcarrying box are equalized in accordance with the distribution of the load carried therein.

Claim 3

A hoist mechanism as defined in claim 1 wherein each said jackknife hoist means comprises an elongated pivot bar fixed to the first leg of said bellcrank connector means and a lifting arm pivotally hinged at one end to the underside of said load-carrying box.

Claim 4

A hoist mechanism as defined in claim 1, wherein said jackknife hoist means comprises an elongated pivot bar fixed at one and to said first bellcrank leg, and an obtuse-angled lifting arm the respective legs of which are of unequal length, means pivotally hinging the shorter leg of said lifting arm to said pivot bar, means for pivotally hinging the longer leg of said lifting arm to the underside of said load-carrying box and means at the apex of said legs for pivotally hinging said lifting arm to said power means.

Claim 5

A hoist mechanism as defined in claim 1, wherein said power means comprises a piston and cylinder motor associated with each jackknife hoist means and a source of pressure fluid on said vehicle for powering said motors, and control means for controlling the application of pressure fluid to and the discharge of pressure fluid from said motors to respectively raise or lower said load-carrying box.

Claim 6

A hoist mechanism as definEd in claim 4, wherein said source of pressure fluid comprises a power steering pump secured to and operatively controlling the steering of said wheeled vehicle.

Claim 7

A hoist mechanism for lifting a load-carrying box hinged for tilting movement on the chassis of a wheeled, dirigible, automotive vehicle, said hoist comprising, in combination, a torsion bar extending transversely of the vehicle chassis at a point spaced from the hinge between the box and the chassis, means journaling said torsion bar for axial rotation with respect to said chassis, bellcrank connector means fixed at each end of said torsion bar outboard of said chassis, a pair of parallel elongated pivot bars fixed respectively to said bellcrank connector means, a pair of lifting arms, means pivotally hinging each lifting arm at one end to the free end of an adjacent one of said pivot bars, means pivotally hinging each lifting arm at its other end to the underside of the load-carrying box at spaced apart points thereon, a pair of hoist motors, means pivotally hinging a motor between each said bellcrank connector means and a point intermediate the ends of a respective lifting ram, said motors being operable for jackknifing said pivot bars and said lifting arms about the pivot means joining the same while applying a load unbalance compensating torque to said torsion bar whereby lifting forces at each side of the load-carrying box are equalized in accordance with the distribution of the load carried by the box.

Claim 8

A hoist mechanism for lifting a load-carrying box hinged for tilting movement on the chassis of a wheeled, dirigible, automotive vehicle, said hoist comprising, in combination, a torsion bar extending transversely of the vehicle chassis at a point spaced from the hinge between the box and the chassis, means journaling said torsion bar for axial rotation with respect to said chassis, bellcrank connector means fixed at each end of said torsion bar outboard of said chassis, a pair of parallel elongated pivot bars fixed respectively to said bellcrank connector means, a pair of lifting arms, means pivotally hinging each lifting arm at one end to the free end of an adjacent one of said pivot bars, means pivotally hinging each lifting arm at its other end to the underside of the load-carrying box at spaced apart points thereon, a pair of hoist motors, means pivotally hinging a motor between each said bellcrank connector means and a point intermediate the ends of a respective lifting ram, said motors being operable for jackknifing said pivot bars and said lifting arms about the pivot means joining the same while applying a load unbalance compensating torque to said torsion bar whereby lifting forces at each side of the load-carrying box are equalized in accordance with the distribution of the load carried by the box.