US 6,722,675 B2 · Steerable load-carrying assemblies

Abstract

A moveable load-carrying assembly including a chassis (1) having a plurality of wheels (6) arranged as a first wheel set and a second wheel set, each wheel (6) being rotatable and swivellable relative to the chassis (1); the wheels (6) of the first wheel set being connected by a first linkage (21), and the wheels (6) of the second wheel set being connected by a second linkage (22); and wherein one of the wheels (6) of the second wheel set is linked to the opposite one of the wheels (6) of the first wheel set by a link (11) such that when one of the wheels (6) of the first wheel set is swivelled in one direction relative to the chassis (1), all the wheels (6) of the first wheel set swivel in that direction in unison, and all the wheels (6) of the second wheel set swivel in the opposite direction in unison. Means are included to provide three distinct modes of operation for a wheel set, the modes corresponding to straight-line travel, fully-steerable travel and a braking mode. The assembly also includes an apparatus for returning the steerable wheels to a straight-line position, comprising a first member (203) associated with a tie rod (202) operably connected to one or more steerable wheels, at least one further member (205, 206) pivotably associated with a fixed chassis member (201) and a resilient means (209) associated with the further member.

Claims10

Dependent claims

Apparatus for controlling the direction of travel of a steerable assembly, the apparatus including:

(i) a first member associated with a tie-rod operably connected to one ore more steerable wheels of the assembly;
(ii) at least one further member associated with a fixed chassis member of the assembly, the at least one further member being selectively and continuously pivotably moveable relative to the fixed chassis member between respective inoperative and operative end positions;
and
(iii) resilient means associated with the at least one further member, the arrangement being such that, in use, when the steerable wheels of said assembly undergo a change in direction, the first member and the at least one further member come into contact, whereby the resilient means acts to return the at least one further member to its inoperative position, thereby correcting the steering of said assembly.

1 more element

A hand-movable load-carrying assembly including a chassis having a plurality of wheels arranged as a first wheel set and a second wheel set, each wheel being rotable and swivellable relative to the chassis;

the wheels of the first wheel set being connected by a first linkage, and the wheels of the second wheel set being connected by a second linkage;
one of the wheels of the second wheel set being linked to the opposite one of the wheels of the first wheel set by a link such that when one of the wheels of the first wheel set is swivelled in one direction relative to the chassis, all to wheels of the first wheel set swivel in that direction in unison, and all the wheels of the second wheel set swivel in the opposite direction in unison;
and wherein each wheel has a substantially vertical swivel axle about which it can swivel relative to the chassis;
a boss being mounted on each swivel axle, each wheel being rotably mounted on a stub axle, each stub axle being mounted to its respective boss remote from the swivel axle to enable each wheel to act in the manner of a caster;
said assembly fitted with an apparatus for controlling the direction of travel of a steerable assembly, the apparatus including:
(i) a first member associated with a tie-rod operably connected to one or more steerable wheels of the assembly;
(ii) at least one further member associated with a fixed chassis member of the assembly, the at least one further member being selectively and continuously pivotably moveable relative to the fixed chassis member between respective inoperative and operative end positions;
and
(iii) resilient means associated with the at least one further member, the arrangement being such that, in use, when the steerable wheels of said assembly undergo a change in direction, the first member and the at least one further member come into contact, whereby the resilient means acts to return the at least one further member to its inoperative position, thereby correcting the steering of said assembly;
and
wherein the tie-rod is the first linkage or the second linkage.

8 more elements

Dependencies are inferred from the claim text.

Steerable load-carrying assemblies

Life of this patent

Steerable load-carrying assemblies

Life of this patent

Abstract

Claims10