Obstacle traversing wheelchair
View Patent ↗A wheelchair suspension is provided. The wheelchair suspension includes a frame, a front caster pivot arm, a drive assembly, and a rear caster. The front caster pivot arm is pivotally connected to the frame. The front caster is coupled to a front end of the front caster pivot arm. The drive assembly is pivotally connected to the front caster pivot arm. The drive assembly comprises a drive wheel and a motor that drives the drive wheel. Torquing of the drive wheel by the motor in a forward direction causes the drive assembly to pivot with respect to the front caster pivot arm such that the drive wheel moves forward toward the front caster and a distance between a support surface and the connection between of the drive assembly and the front caster pivot arm increases.
1. A method of climbing an obstacle with a wheelchair that includes a frame, a front caster pivot arm, a front caster coupled to the front caster pivot arm, a drive assembly that includes a motor that drives a drive wheel, and a rear caster, the method comprising:
torquing the drive wheel with the motor in a forward direction;
wherein said torquing causes the drive assembly to pivot about a pivotal connection to the front caster pivot arm;
wherein said pivoting of the drive assembly causes the drive wheel to move forward toward the front caster and causes a distance between a support surface and the pivotal connection of the drive assembly to the front caster pivot arm to increase;
passing over the obstacle with the front caster and the drive wheel.
2. The method of claim 1 wherein the front caster pivot arm is pivots with respect to the frame at a first pivot axis and the drive assembly pivots with respect to the front caster pivot arm at a second pivot axis.
3. The method of claim 2 wherein the first pivot axis is spaced apart from the second pivot axis.
4. The method of claim 2 wherein the first pivot axis is not aligned with the second pivot axis.
5. The method of claim 1 further comprising biasing the front caster downward into contact with the support surface.
6. The method of claim 1 further biasing the drive wheel downward into contact with the support surface.
7. The method of claim 6 wherein drive wheel is biased downward by a spring that is interposed between the drive assembly and the front caster pivot arm.
8. The method of claim 1 further comprising biasing the front caster downward into contact with the support surface and biasing the drive wheel downward into contact with the support surface.
9. The method of claim 8 wherein the drive wheel is biased downward by a spring that is interposed between the drive assembly and the front caster pivot arm.