Multi-pivot vehicle suspension
View Patent ↗An all terrain vehicle and suspension providing frame members that pivot relative to each other and independent of supported track assemblies. Suspension frame sections pivot at supported bearings and torsion couplers. An endless track of each track assembly is trained around a framework having a drive sprocket and sets of idler wheels. The track assemblies independently pivot relative to the vehicle from a track suspension frame and supported sets of idler wheels mounted to torsion biased rocker arms that resist and bias the rocker arms and idler wheels to an equilibrium position and conformally shape the track to the terrain. Improved track drive lug surfaces are shaped to prevent track derailment. The vehicle frame and track assemblies independently rise, fall and pivot as obstacles of differing configurations and types are encountered to stabilize and maintain an operator body substantially parallel to the ground.
1. A vehicle comprising:
a) a chassis framework supporting a body and comprising a center longitudinal frame section and first and second longitudinal frame sections, wherein said first and second longitudinal frame sections extend in substantially parallel relation to said center frame section, wherein first and second pivot axles respectively couple said first and second longitudinal frame sections to said center frame section such that the first and second longitudinal frame sections can pivot longitudinally about said center frame section independently of the other;
b) a cross frame section coupled to said center frame section, wherein said cross frame section transversely extends between said first and second longitudinal frame sections, wherein opposite ends of said cross frame section are pivotally coupled to said first and second longitudinal frame sections, and including a torsion means for resiliently resisting and torsionally biasing rotation of said cross frame section and said first and second longitudinal frame sections relative to said center frame section to an equilibrium position;
c) first and second drive axles mounted to transversely extend from said center frame section independent of said cross frame section and coupled to opposed fore and aft ends of said first and second longitudinal frame sections; and
d) a plurality of track assemblies, wherein each track assembly is coupled to pivot about an end of one of said first and second drive axles at the fore or aft end of one of said first or second longitudinal frame sections to support said chassis framework and body, wherein each track assembly includes a drive sprocket, a plurality of idler wheels and a track trained about said sprocket and idler wheels to rotate and direct vehicle movement, and wherein each track assembly is resiliently biased to an equilibrium position relative to said one of said first and second longitudinal frame sections, whereby each track assembly is able to resiliently pivot relative to the respective one of the first and second longitudinal frame sections and independent of movement of the cross frame and the first and second longitudinal frame sections about the center frame section upon encountering changing terrain contours to maintain a horizontal orientation of said body relative to the terrain.
2. A vehicle as set forth in claim 1 wherein the torsion means comprises an elastomer member mounted between said center frame and cross frame sections to resist rotation of said cross frame section away from an equilibrium position.
3. A vehicle as set forth in claim 1 wherein said chassis framework comprises a second cross frame section, wherein said second cross frame sections is pivotally coupled to said center frame section and transversely extends between said first and second longitudinal frame sections, wherein ends of said second cross frame section are pivotally coupled to said first and second longitudinal frame sections, and including a second torsion means for resiliently resisting and torsionally biasing rotation of said second cross frame section relative to said center frame section to an equilibrium position.
4. A vehicle as set forth in claim 1 wherein at least one of said track assemblies includes first and second yokes pivotally coupled to a track support frame member, wherein each of said first and second yokes are coupled to at least two of said idler wheels, and including yoke biasing means for torsionally biasing said first and second yokes to resist and bias rotation of said first and second yokes to an equilibrium position and such that the contour of said track can change shape to conform to encountered obstacles and as said track assembly pivots from one of said first and second longitudinal frame sections.
5. A vehicle as set forth in claim 4 wherein said at least one track assembly includes first and second arcuate plates and an intervening slippery bearing piece, wherein said first and second plates pivot relative to each other, wherein said first and second yokes are mounted to pivot from said second plate at first and second yoke pivot axles, and wherein said yoke biasing means include a plurality of resilient elastomer members mounted to resist and bias rotation of said first and second yoke pivot axles relative to said second plate.
6. A vehicle as set forth in claim 1 wherein the torsion means comprises a collar mounted about a third axle and coupling said cross frame section to said center frame section and wherein a plurality of elastomer members are mounted between said third axle and collar to resist rotation of said third axle and bias said third axle and cross frame section to an equilibrium position.
7. A vehicle as set forth in claim 1 including means for steering each of said track assemblies independent of the other track assemblies.
8. A vehicle comprising:
a) a chassis framework supporting a body and comprising a center longitudinal frame section and first and second longitudinal frame sections, wherein said first and second longitudinal frame sections extend in substantially parallel relation adjacent opposite lateral sides of said center frame section, wherein first and second pivot axles respectively couple said first and second longitudinal frame sections to said center frame section such that the first and second longitudinal frame sections can pivot longitudinally about said center frame section independently of the other;
b) first and second cross frame sections coupled to independently pivot from said center frame section, wherein each of said first and second cross frame sections transversely extends between said first and second frame sections, wherein the opposite ends of each of said first and second cross frame sections are pivotally coupled to said first and second frame sections, and including torsion means for resiliently resisting and torsionally biasing rotation of each of said first and second cross frame sections and said first and second longitudinal frame sections relative to said center frame section to an equilibrium position;
c) first and second drive axles mounted to transversely extend from said center frame section independent of said first and second cross frame sections and coupled to opposed fore and aft ends of said first and second longitudinal frame sections;
d) a plurality of track assemblies, wherein each track assembly is coupled to pivot about an end of one of said first and second drive axles at the fore and aft ends of said first or second longitudinal frame sections to support said chassis framework and body, wherein each track assembly includes a drive sprocket, a plurality of idler wheels and a track trained about said sprocket and idler wheels to rotate and direct vehicle movement, and wherein each track assembly is resiliently biased to an equilibrium position relative to said first and second longitudinal frame sections, whereby each track assembly is able to resiliently pivot relative to the first and second longitudinal frame sections independent of movement of the first and second cross frame sections and the first and second longitudinal frame sections about the center frame section upon encountering changing terrain contours to maintain a horizontal orientation of said body relative to the terrain; and
e) means for steering each of said track assemblies independent of the other track assemblies.
9. A vehicle as set forth in claim 8 wherein at least one of said track assemblies includes first and second yokes pivotally coupled to a track support frame member, wherein each of said first and second yokes are coupled to at least two of said idler wheels, and including yoke biasing means for torsionally biasing said first and second yokes to resist and bias rotation of said first and second yokes to an equilibrium position and such that the contour of said track can change shape to conform to encountered obstacles and as said track assembly pivots from said chassis framework.
10. A vehicle as set forth in claim 9 wherein said at least one track assembly includes first and second arcuate plates and an intervening slippery bearing piece wherein said first and second plates pivot relative to each other, wherein said first and second yokes are mounted to pivot from said second plate at first and second pivot axles, and wherein said yoke biasing means includes a plurality of resilient elastomer members mounted to resist and bias rotation of said first and second yoke pivot axles relative to said second plate.