A trailer for towing by a power vehicle is provided and generally includes a frame and a tandem wheel assembly. The frame forms an undercarriage chassis which the tandem wheel assembly is positioned there under. The undercarriage chassis includes a steerable rear wheel assembly, a steerable front wheel assembly, and an extension assembly moving the front wheel assembly between trailing position and a self-propelled position where the rear wheel assembly and the front wheel assembly are positioned to equally support the undercarriage chassis.

A trailer for towing by a power vehicle is provided and generally includes a frame and a tandem wheel assembly. The frame forms an undercarriage chassis which the tandem wheel assembly is positioned there under. The undercarriage chassis includes a rear wheel assembly, a front wheel assembly, and an extension assembly moving the front wheel assembly between trailing position and a self-propelled position. At least one of the wheel assemblies is powered by a selectively engageable drive assembly including a motor, transmission, driveshaft, selectively engageable clutch and hub, to drive the rotation of at least one of the wheels.

A torsion beam of a coupled torsion beam axle may include an external beam having a first cross-section in which an external protrusion of a middle end portion of the external beam is formed to protrude toward upward in a longitudinal direction of the external beam, and external skirt portions are vertically extended along the longitudinal direction at both end portions of the external protrusion; and an internal beam having a second cross-section in which an internal protrusion of a middle end portion in the internal beam is inserted into the external beam to face the external protrusion of the external beam, and internal skirt portions are extended in a vertical direction at both end portions of the internal protrusion, and each external surface of the internal skirt portions and each internal surface of the external skirt portions are surface-bonded in a mutually matched state. A gap is formed between an external surface of the internal protrusion and an internal surface of the external protrusion to form a closed cross-section.

A torsion beam of a coupled torsion beam axle may include an external beam having a first cross-section in which an external protrusion of a middle end portion of the external beam is formed to protrude toward upward in a longitudinal direction of the external beam, and external skirt portions are vertically extended along the longitudinal direction at both end portions of the external protrusion; and an internal beam having a second cross-section in which an internal protrusion of a middle end portion in the internal beam is inserted into the external beam to face the external protrusion of the external beam, and internal skirt portions are extended in a vertical direction at both end portions of the internal protrusion, and each external surface of the internal skirt portions and each internal surface of the external skirt portions are surface-bonded in a mutually matched state. A gap is formed between an external surface of the internal protrusion and an internal surface of the external protrusion to form a closed cross-section.

A wheeled work vehicle (1) comprises a forward chassis part (4) and a rearward chassis part (5) pivotally connected about a substantially vertically extending primary pivot axis (7) for steering thereof. A pair of forward ground engaging wheels (29) are carried on a forward suspension unit (32), and a pair of rearward ground engaging wheels (30) are carried on a rearward suspension unit (33). The forward suspension unit (32) is pivotally connected to the forward chassis part (4) by a pair of main forward transverse pivot shafts (63) pivotally coupled to the forward chassis part (4) by corresponding main forward pivot mountings (65). The main forward transverse pivot shafts (63) defines a main forward transverse pivot axis (59) about which the forward suspension unit (32) is pivotal relative to the forward chassis part (4). The forward suspension unit (32) comprises a pair of spaced apart trailing arms (35) which are joined by a torsion shaft (68) of tubular steel, which is rigidly connected to the trailing arms (35). The torsion shaft (68) defines a torsional axis (70), and permits limited upward and downward pivotal type torsional deflection of the trailing arms (35) relative to each other. The rearward suspension unit (33) is substantially similar to the forward suspension unit (32) and is coupled to the rearward chassis part (5) about a pair of main rearward transverse pivot shafts (87) in a similar manner as the forward suspension unit (32) is coupled to the forward chassis part (4).

A trailer for towing by a power vehicle is provided and generally includes a frame and a tandem wheel assembly. The frame forms an undercarriage chassis which the tandem wheel assembly is positioned there under. The undercarriage chassis includes a rear wheel assembly, a front wheel assembly, and an extension assembly moving the front wheel assembly between trailing position and a self-propelled position. At least one of the wheel assemblies is powered by a selectively engageable drive assembly including a motor, transmission, driveshaft, selectively engageable clutch and hub, to drive the rotation of at least one of the wheels.

A trailer for towing by a power vehicle is provided and generally includes a frame and a tandem wheel assembly. The frame forms an undercarriage chassis which the tandem wheel assembly is positioned there under. The undercarriage chassis includes a steerable rear wheel assembly, a steerable front wheel assembly, and an extension assembly moving the front wheel assembly between trailing position and a self-propelled position where the rear wheel assembly and the front wheel assembly are positioned to equally support the undercarriage chassis.

A trailer for towing by a power vehicle is provided and generally includes a frame and a tandem wheel assembly. The frame forms an undercarriage chassis and the tandem wheel assembly positioned under the undercarriage chassis. The tandem wheel assembly includes a rear wheel assembly and a front wheel assembly. An extension assembly is provided and moves the front wheel assembly between trailing position and a self-propelled position where the rear wheel assembly and the front wheel assembly are positioned to equally support the undercarriage chassis.

A twist axle assembly (20) of a vehicle includes a pair of trailing arms (22) and a twist beam (24) having a base portion (46) extending along an axis (A) between first and second twist beam ends (42, 44). The twist beam (24) includes a pair of side walls (48) extending downwardly from the base portion (46) and each disposed in spaced relationship with the trailing arms (22). At least one mounting bracket (54) extends from a first mounting bracket end (56) disposed in abutting relationship with a respective trailing arm (22) to a second mounting bracket end (58) disposed in overlaying relationship the side walls (48) of the twist beam (24) for allowing the mounting bracket to axially slip or slide along the side walls (48) of the twist beam (24) and provide for lateral or axial adjustment of the twist axle assembly (20) during the manufacturing process.

An axle assembly includes a first rail assembly, a second rail assembly and an open-section twist beam connected to the first rail assembly and the second rail assembly. The twist beam includes an upper wall, a lower wall and rear wall wherein the upper wall and the lower wall are connected by the rear wall to define an open portion of the twist beam where the upper wall and the lower wall are separated by a vertical distance. The open portion of the twist beam is forward facing. The axle assembly further includes a torsion bar that extends through and is connected within the open portion of the twist beam.