US 6,308,976 B1Granted

Steerable trailers

OwnerGeorge Wallace Mitchellinventor

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Abstract

A multiple axle trailer is disclosed consisting of a main chassis articulated to a tractor unit and a sub-chassis relative to which the main chassis rotates on a turntable. The sub-chassis has a pair of forward wheel (3) and pair of rear wheels (4), each of which rotates on a stub axle and king pin assembly (6). A steering mounting has two swinging arms depending from the main chassis, joined at their free ends by a horizontal tie. A primary link of a linkage mechanism is coupled to the horizontal tie, the linkage mechanism coupling the wheels to the steering mounting such that rotation of the main chassis relative to the sub-chassis causes the stub axles to pivot about the king pins. Movement of the swinging arms causes the line of action of the primary link to cross the axis about which the main chassis rotates relative to the sub-chassis, reversing the direction of steer for when the trailer is backed up.

Claims21

Dependent claims

A trailer comprising:

a main chassis adapted to be articulated to a tractor unit;
a sub-chassis (1) relative to which the main chassis may rotate about a substantially vertical axis and including a laterally spaced pair of forward steerable wheels (3) and a laterally spaced pair of rear steerable wheels (4), each sub wheel being pivotable relative to the sub-chassis (1) about a respective substantially vertical axis;
and
a linkage mechanism coupling each of the steerable wheels (3,4) to a steering mounting (22) on the main chassis such that rotation of the main chassis relative to the sub-chassis (1) causes the wheels to pivot about their respective axes and including at least one primary link (18) having first and second ends, the first end being coupled to the steering mounting (22);
wherein the steering mounting (22) is movable relative to the main chassis between a first position and a second position such that said motion causes a line of action joining the first and second ends of each primary link (18) to cross the axis (21) about which the main chassis rotates relative to the sub-chassis (1).

2 more elements

Dependencies are inferred from the claim text.