received by the I nternational Bureau on 1 7 May 201 4 (1 7.05.201 4)

What is claimed is:

1. An apparatus, comprising:

an axle structured to span in a length axis direction between a pair of wheels such that said wheels are steered in unison by said axle, displacement of said axle being constrained by structure carried by a baseplate and effective to cause steering rotation of said axle about a dynamic hanger rotation axis; wherein:

during a turn maneuver between a maximum right turn position and a maximum left turn position:

said dynamic hanger rotation axis always passes through a static pivot point at a locus that is static with respect to said baseplate;

said dynamic hanger rotation axis passes through at least two instantaneous pivot points that are not co-linear with said static pivot point; and

roll of said baseplate about a roll axis causes a change in action angle of said axle during at least a portion of said turn maneuver.

2. The apparatus according to claim 1 , wherein:

said axle is carried by a hanger; and

support structure carried by said baseplate is arranged to cooperate with pivot structure

associated with a proximal end of said hanger effective to cause displacement, relative to said baseplate, of an instantaneous pivot point as said axle moves between said maximum right turn position and said maximum left turn position.

3. The apparatus according to claim 2, wherein:

said support structure comprises a pivot bushing; and

said pivot structure comprises a first pivot element and a second pivot element structured in harmony with said pivot bushing such that:

during change in a macro-turn in a first direction, said first pivot element defines a first instantaneous pivot point through which said dynamic pivot axis passes, and said second pivot element rotates around said first pivot element; and

din ing change in a macro-turn in a second direction, said second pivot clement defines a second instantaneous pivot point through which said dynamic pivot axis passes, and said first pivot element rotates around said second pivot element.

4. The apparatus according to claim 3, wherein:

said first and second pivot elements are journal mounted with respect to said hanger to perm it their rotation about respective rotational axes.

5. The apparatus according to claim 4, wherein:

said first and second pivot elements fire structured in harmony with cooperating first and second detents in a socket carried by said pivot bushing such that said first pivot element may register with said first detent to define a location of said first instantaneous pivot point, and said second pivot element may register with said second detent to define a location of said second instantaneous pivot point.

6. The apparatus according to claim 5, further comprising:

a third detent and a fourth detent, wherein:

said third detent is disposed to register with said second pivot element to define a maximum- turn configuration in said first direction; and

said fourth detent is disposed to register with said first pivot clement to define a maximum- turn configuration in said second direction.

7. The apparatus according to claim 3, wherein:

said pivot structure further comprises a shelf, at least a portion of said shelf being structured to cooperate with a portion of said pivot bushing effective to provide a micro-steering capability for said apparatus at an essentially zero-turn configuration of said axle.

8. The apparatus according to claim 1 , wherein:

.said apparatus is structured and arranged to cause an increase in action angle in

correspondence with an increase in steering rotation of said axle.

9. The apparatus according to claim 1 , wherein:

said apparatus is structured and arranged in cause a decrease in action angle in

correspondence with an increase in steering rotation of said axle.

10. The apparatus according to claim 1, further comprising:

a kingpin anchored to said baseplate, said static pivot point being disposed on the centerline of said kingpin;

a hanger carrying said axle, said hanger being anchored to said baseplate effective to permit rotation of said hanger about said dynamic axis; and

a turn-limiting mechanism effective to provide a hard turn stop at maximum left turn and maximum right turn configurations; wherein:

said turn-limiting mechanism is structured to avoid making contact with said kingpin.

1 1. The apparatus according to claim 1 , wherein:

from the perspective of a surface on which said apparatus is rolled, said static pivot point is disposed between the centerline of said axle and a selected one of said instantaneous pivot points.

12. The apparatus according to claim 1. wherein:

from the perspective of a surface on which said apparatus is rolled, said static pivot point is disposed on the opposite side of the centerline of said axle from a selected one of said instantaneous pivot points.

13. The apparatus according to claim 1. wherein:

said baseplate is coupled to a hanger that carries said axle; and

from the perspective of a surface on which said apparatus is rolled, said static pivot point is disposed closer to the inside end of said baseplate than a selected one of said instantaneous pivot points.

14. The apparatus according to claim 1 , wherein:

said baseplate js coupled to a hanger that carries said axle; and

from the perspective of a surface on which said apparatus is rolled, said static pivot point is disposed closer to the outside end of said baseplate than a selected one of said instantaneous pivot points.

15. The apparatus according to claim 1 , further comprising:

a hanger carrying said axle;

a pair of spaced apart hanger pivot anchors defined by structure carried by said baseplate, said pivot anchors being effective to define a hanger pivot axis extending therebetween;

a yoke disposed to pivot around said hanger pivot axis; and

a kingpin held by said yoke to dispose the centerline of said kingpin normal to said hanger pivot axis; wherein:

said hanger is structured to rotate about said centerline of said kingpin while maintaining dynamic contact with said baseplate.

! 6. The apparatus according to claim 15, further comprising:

means to urge dynamic contact between said hanger and said baseplate in the absence of gravity-enforced contact.

17. An apparatus, comprising:

a hanger carrying an axle, said axle being structured to span in a length axis direction

between a pair of wheels such that said wheels are steered in unison by said axle; a baseplate coupled to said hanger effective to permit rotation of said hanger about a dynamic hanger rotation axis;

a static mechanism structured to enforce a static pivot point at a locus through which said dynamic hanger rotation axis passes during turning operation of said apparatus; and a dynamic mechanism structured to cause said dynamic hanger rotation axis to pass through a plurality of dynamic hanger pivot points during said turning operation; wherein: roll of said baseplate about a roll axis is operable to cause a steering rotation of said axle and a change in the action angle of said axle,

18. The apparatus according to claim 17, wherein:

said dynamic turning mechanism is structured and arranged to cause a nonlinear change in turn angle responsive to change in tilt angle of said baseplate.

19. The apparatus according to claim 17, wherein:

said dynamic turning mechanism is structured and arranged to cause an increase in action angle in correspondence with an increase in steering rotation of said axle.

20. An apparatus, comprising:

a hanger carrying an axle, said axle being structured to span in a length axis direction

between a pair of wheels such that said wheels are steered in unison by said axle; and a baseplate coupled to said hanger effective to permit rotation of said hanger about a dynamic hanger rotation axis such that tilting said baseplate around a conveyance roll axis can cause a change in action angle of said apparatus; wherein:

said dynamic hanger rotation axis passes through a static pivot point.