Wheelchair suspension
View Patent ↗A wheelchair includes a pivoting drive assembly having a drive wheel, a motor drive connected to the drive wheel, and a first pivoting linkage fixedly attached to the motor drive. The pivoting drive assembly is pivotally coupled to a frame at a first frame pivot axis such that the drive wheel, motor drive, and first pivoting linkage pivot about the first frame pivot axis as a unit. The wheelchair further includes a second pivoting linkage and a front caster assembly. The second pivoting linkage is pivotally coupled to the frame at a second frame pivot axis. The first pivoting linkage is pivotally coupled to the front caster assembly at a first front caster pivot axis and the second pivoting linkage is pivotally coupled to the front caster assembly at a second front caster pivot axis.
1. A wheelchair comprising:
a frame;
a pivoting drive assembly that includes:
a drive wheel;
a motor drive connected to the drive wheel; and
a first pivoting linkage fixedly attached to the motor drive, wherein the pivoting drive assembly is pivotally coupled to the frame at a first frame pivot axis such that the drive wheel, motor drive, and first pivoting linkage pivot about the first frame pivot axis as a unit;
a second pivoting linkage pivotally coupled to the frame at a second frame pivot axis; and
a front caster assembly, wherein the first pivoting linkage is pivotally coupled to the front caster assembly at a first front caster pivot axis and the second pivoting linkage is pivotally coupled to the front caster assembly at a second front caster pivot axis.
2. The wheelchair of claim 1 wherein the motor drive is fixedly connected to a mounting bracket of the first pivoting linkage.
3. The wheelchair of claim 1 wherein the motor drive is fixedly connected to the first pivoting linkage at a position below the first pivoting linkage.
4. The wheelchair of claim 1 wherein the first frame pivot axis is between an axis of rotation of the drive wheel and the front caster assembly.
5. The wheelchair of claim 1 wherein the second frame pivot axis is between the first frame pivot axis and the front caster assembly.
6. The wheelchair of claim 1 wherein a distance between the first frame pivot axis and the first front caster pivot axis is greater than a distance between the second frame pivot axis and the second front caster pivot axis.
7. The wheelchair of claim 1 further comprising a spring connected to the first pivoting linkage and to the frame at a position that is between the first pivoting linkage and the rear caster.
8. The wheelchair of claim 7 wherein the spring biases a front caster of the front caster assembly downward.
9. The wheelchair of claim 1 wherein torque applied to the drive wheel urges the front caster assembly away from a support surface.
10. The wheelchair of claim 1 wherein torque applied to the drive wheel lifts the front caster assembly off of a support surface.
11. The wheelchair of claim 1 further comprising at least one rear caster coupled to the frame.
12. A wheelchair comprising:
a frame;
first and second independent pivoting assemblies coupled to opposite sides of the frame, wherein each of the first and second pivoting assemblies includes:
a drive wheel;
a motor drive connected to the drive wheel;
a first pivoting linkage fixedly attached to the motor drive, wherein the first pivoting linkage is pivotally coupled to the frame at a first frame pivot axis such that the drive wheel, motor drive, and first pivoting linkage pivot about the first frame pivot axis as a unit;
a second pivoting linkage pivotally coupled to the frame at a second frame pivot axis; and
a front caster assembly, wherein the first pivoting linkage is pivotally coupled to the front caster assembly at a first front caster pivot axis and the second pivoting linkage is pivotally coupled to the front caster assembly at a second front caster pivot axis.
13. The wheelchair of claim 12 wherein the motor drive is fixedly connected to a mounting bracket of the first pivoting linkage.
14. The wheelchair of claim 13 wherein the motor drive is fixedly connected to the first pivoting linkage at a position below the first pivoting linkage.
15. The wheelchair of claim 13 wherein the first frame pivot axis is between an axis of rotation of the drive wheel and the front caster assembly.
16. The wheelchair of claim 13 wherein the second frame pivot axis is between the first frame pivot axis and the front caster assembly.
17. The wheelchair of claim 13 wherein a distance between the first frame pivot axis and the first front caster pivot axis is greater than a distance between the second frame pivot axis and the second front caster pivot axis.
18. The wheelchair of claim 13 further comprising a spring connected to the first pivoting linkage and to the frame at a position that is between the first pivoting linkage and the rear caster.
19. The wheelchair of claim 18 wherein the spring biases a front caster of the front caster assembly downward.
20. The wheelchair of claim 13 wherein torque applied to the drive wheel urges the front caster assembly away from a support surface.
21. The wheelchair of claim 13 wherein torque applied to the drive wheel lifts the front caster assembly off of a support surface.
22. The wheelchair of claim 13 further comprising at least one rear caster coupled to the frame.