Trailing arm suspension

In an undercarriage of the type including an elongate hollow load bearing primary frame a plurality of primary axles positioned at axially spaced points along the primary frame for supporting the primary axles for rotation with respect thereto, transmission means mounted within the primary frame for drivingly interconnecting at least two of the primary axles, and drive means mounted on the primary frame and drivingly connected to the transmission means for cooperation therewith to drive the interconnected primary axles, the improvement comprising:

• a plurality of secondary frames each individual to one of the primary axles;
• means supporting each of the secondary frames for pivotal movement relative to the primary frames about an axis which is coincident with the axis of rotation of its associated primary axle;
• a plurality of secondary axles each individual to one of the primary axles;
• means mounted on the secondary frames for supporting the secondary axles for rotation about axes extending parallel to the axes of rotation of the primary axles;
• secondary means mounted within the secondary axles for drivingly interconnecting each primary axle and the secondary axle individual thereto;
• a shock absorber connected between each of the secondary frames and the primary frame for controlling the pivotal movement of the secondary frame relative thereto;
• a spring connected between each of the secondary frames and the primary frame for controlling the pivotal movement of the secondary frame relative thereto;
• and
• a double acting hydraulic cylinder connected between each of the secondary frames and the primary frame for selectively positioning the axles of the secondary frames to facilitate skid steering of the undercarriage, for selectively positioning the axles of the secondary frames to facilitate high speed operation of the undercarriage, and for vertically extending and retracting all of the wheel members relative to the primary frame to facilitate operation when loaded and unloaded and to vertically position the undercarriage with respect to an underlying surface.

An undercarriage comprising:

• an elongated hollow load bearing primary frame;
• a plurality of elongate hollow secondary frames;
• means supporting the secondary frames at longitudinally spaced points along the primary frame for pivotal movement with respect thereto with the secondary frames normally extending angularly downwardly from the primary frame and substantially parallel to one another;
• a plurality of primary axles each individual to one of the secondary frames;
• means supporting the primary axles for rotation about axes coincident with the axes of pivotal movement of the secondary frames;
• transmission means mounted in the primary frame for drivingly interconnecting all of the primary axles;
• drive means mounted in the primary frame and connected to the transmission means for cooperation therewith to drive all of the primary axles;
• a plurality of secondary axles each individual to one of the secondary frames;
• means for supporting each of the secondary axles on its secondary frame for rotation about an axis extending parallel to the axis of rotation of the primary axle individual thereto;
• a plurality of secondary transmission means each for drivingly interconnecting one of the primary axles and the secondary axles individual thereto and each including a sprocket mounted on the primary axle within the secondary frame, a sprocket mounted on the secondary axle within the secondary frame and a drive chain enclosed within the secondary frame for drivingly interconnecting the two sprockets;
• each of the secondary frames having a lever arm mounted thereon;
• a plurality of lever arms mounted on the primary frame in alignment with the lever arms on the secondary frames;
• a spring connected between the lever arm on each of the secondary frames and the corresponding lever arm on the primary frame;
• a shock absorber connected between the lever arm on each of the secondary frames and the corresponding lever arm on the primary frame;
• and
• hydraulic cylinder means each connected at one end to each of the springs and to the associated shock absorber and each connected at the other end to the associated lever arm for selectively positioning the secondary axles of selected secondary frames substantially out of alignment with a plane extending tangent to at least two of the secondary axles and thereby facilitating skid steering, for selectively aligning all of the secondary axles and thereby facilitating high speed operation, and for vertically extending and retracting all of the wheel members relative to the primary frame to facilitate operation when loaded and unloaded and to vertically position the undercarriage with respect to an underlying surface.