Wheelchair suspension
View Patent ↗A suspension for a vehicle is provided. The suspension includes, for example, a frame, at least one drive assembly and at least one caster pivot arm. The at least one drive assembly and the at least one caster pivot arm are coupled to enhance the vehicle's ability to traverse obstacles.
1. A wheelchair suspension comprising:
a frame;
a drive assembly pivot arm pivotally connected to the frame;
a drive assembly mounted to the drive assembly pivot arm;
at least one front caster pivot arm pivotally mounted to the frame and coupled to the drive assembly pivot arm;
a front caster coupled to the at least one front caster pivot arm;
wherein the drive assembly pivot arm and the at least one front caster pivot arm are disposed in a crossed configuration such that the drive assembly pivot arm intersects the at least one front caster pivot arm when viewed from the side when the wheelchair is in a neutral operating position and wherein torque applied by the drive assembly urges the front caster upward with respect to a support surface.
2. The wheelchair suspension of claim 1 further comprising at least one rear caster coupled to the frame.
3. The wheelchair suspension of claim 1 wherein the drive assembly pivot arm is pivotally mounted to the frame at a first pivot axis and at least one caster pivot arm is pivotally mounted to the frame at a second pivot axis and the first pivot axis is in front of the second pivot axis on the frame.
4. The wheelchair suspension of claim 1 wherein the drive assembly and the at least one front caster pivot arm are coupled by a variable length motion transfer member.
5. The wheelchair suspension of claim 4 wherein the variable length motion transfer member has a maximum length and is compressible from the maximum length to a shorter length.
6. The wheelchair suspension of claim 5 wherein pulling of the variable length motion transfer member when the variable length motion transfer member is at the maximum length pulls the at least one front caster pivot arm to move the front caster away from the support surface.
7. The wheelchair suspension of claim 4 wherein variable length motion transfer member is a shock absorber.
8. The wheelchair suspension of claim 4 wherein the variable length motion transfer member comprises a spring.
9. The wheelchair suspension of claim 1 wherein the drive assembly and the at least one front caster pivot arm are coupled by a length of flexible material.
10. The wheelchair suspension of claim 1 wherein the drive assembly pivot arm is pivotally connected to the frame at a first pivot axis and the at least one front caster pivot arm comprises first a first caster pivot link pivotally coupled to the frame at a second pivot axis and second front caster pivot link pivotally coupled to the frame at a third pivot axis.
11. The wheelchair suspension of claim 10 wherein the first pivot axis is in front of the second pivot axis and the third pivot axis on the frame.
12. The wheelchair suspension of claim 1 wherein the drive assembly pivot arm is pivotally mounted to the frame at a first pivot axis and said drive assembly pivot arm intersects the at least one front caster pivot arm at a position that is spaced apart from said first pivot axis when viewed from the side when the wheelchair is in said neutral operating position.
13. The wheelchair suspension of claim 12 wherein the at least one caster pivot arm is mounted to the frame at a second pivot axis and said drive assembly pivot arm intersects the at least one front caster pivot arm at a position that is spaced apart from said second pivot axis when viewed from the side when the wheelchair is in said neutral operating position.
14. A wheelchair comprising:
a frame;
a seat supported by the frame;
a pair of suspension assemblies disposed on opposite sides of the frame, each suspension assembly comprising:
a drive assembly pivot arm pivotally connected to the frame;
a drive assembly mounted to the drive assembly pivot arm;
at least one caster pivot arm pivotally mounted to the frame and coupled to the drive assembly pivot arm;
a front caster coupled to the at least one front caster pivot arm;
wherein the drive assembly pivot arm such that the drive assembly pivot arm intersects the at least one front caster pivot arm when viewed from the side when the wheelchair is in a neutral operating position and the at least one caster pivot arm are disposed in a crossed configuration and wherein torque applied by the drive assembly urges the front caster upward with respect to a support surface.
15. The wheelchair of claim 14 further comprising at least one rear caster coupled to the frame.
16. The wheelchair of claim 14 wherein the drive assembly pivot arm is pivotally mounted to the frame at a first pivot axis and at least one caster pivot arm is pivotally mounted to the frame at a second pivot axis and the first pivot axis is in front of the second pivot axis on the frame.
17. The wheelchair of claim 14 wherein the drive assembly and the at least one front caster pivot arm are coupled by a variable length motion transfer member.
18. The wheelchair of claim 17 wherein the variable length motion transfer member has a maximum length and is compressible from the maximum length to a shorter length.
19. The wheelchair of claim 18 wherein pulling of the variable length motion transfer member when the variable length motion transfer member is at the maximum length pulls the at least one front caster pivot arm to move the front caster away from the support surface.
20. The wheelchair of claim 17 wherein variable length motion transfer member is a shock absorber.
21. The wheelchair of claim 17 wherein the variable length motion transfer member comprises a spring.
22. The wheelchair of claim 14 wherein the drive assembly and the at least one front caster pivot arm are coupled by a length of flexible material.
23. The wheelchair suspension of claim 17 wherein the drive assembly pivot arm is pivotally connected to the frame at a first pivot axis and the at least one front caster pivot arm comprises first a first caster pivot arm pivotally coupled to the frame at a second pivot axis and second front caster pivot arm pivotally coupled to the frame at a third pivot axis.
24. The wheelchair suspension of claim 23 wherein the first pivot axis is in front of the second pivot axis and the third pivot axis on the frame.
25. The wheelchair suspension of claim 14 wherein the drive assembly pivot arm is pivotally mounted to the frame at a first pivot axis and said drive assembly pivot arm intersects the at least one front caster pivot arm at a position that is spaced apart from said first pivot axis when viewed from the side when the wheelchair is in said neutral operating position.
26. The wheelchair suspension of claim 25 wherein the at least one caster pivot arm is mounted to the frame at a second pivot axis and said drive assembly pivot arm intersects the at least one front caster pivot arm at a position that is spaced apart from said second pivot axis when viewed from the side when the wheelchair is in said neutral operating position.
27. A wheelchair suspension comprising:
a frame;
a drive assembly pivot arm pivotally connected to the frame;
a drive assembly mounted to the drive assembly pivot arm;
at least one front caster pivot arm pivotally mounted to the frame and coupled to the drive assembly pivot arm;
a front caster coupled to the at least one front caster pivot arm;
wherein the drive assembly pivot arm and the at least one front caster pivot arm are disposed in a crossed configuration such that the drive assembly pivot arm intersects the at least one front caster pivot arm when viewed from the side when the wheelchair is in a neutral operating position.
28. The wheelchair suspension of claim 27 further comprising at least one rear caster coupled to the frame.
29. The wheelchair suspension of claim 27 wherein the drive assembly pivot arm is pivotally mounted to the frame at a first pivot axis and at least one caster pivot arm is pivotally mounted to the frame at a second pivot axis and the first pivot axis is in front of the second pivot axis on the frame.
30. The wheelchair suspension, of claim 27 wherein the drive assembly and the at least one front caster pivot arm are coupled by a variable length member.
31. The wheelchair suspension of claim 30 wherein the variable length member has a maximum length and is compressible from the maximum length to a shorter length.
32. The wheelchair suspension of claim 31 wherein pulling of the variable length member when the variable length member is at the maximum length pulls the at least one front caster pivot arm to move the front caster away from the support surface.
33. The wheelchair suspension of claim 30 wherein variable length member comprises a shock absorber.
34. The wheelchair suspension of claim 30 wherein the variable length motion transfer member comprises a spring.
35. The wheelchair suspension of claim 27 wherein the drive assembly and the at least one front caster pivot arm are coupled by a length of flexible material.
36. The wheelchair suspension of claim 27 wherein the drive assembly pivot arm is pivotally connected to the frame at a first pivot axis and the at least one front caster pivot arm comprises first a first caster pivot link pivotally coupled to the frame at a second pivot axis and second front caster pivot link pivotally coupled to the frame at a third pivot axis.
37. The wheelchair suspension of claim 36 wherein the first pivot axis is in front of the second pivot axis and the third pivot axis on the frame.
38. The wheelchair suspension of claim 27 wherein the drive assembly pivot arm is pivotally mounted to the frame at a first pivot axis and said drive assembly pivot arm intersects the at least one front caster pivot arm at a position that is spaced apart from said first pivot axis when viewed from the side when the wheelchair is in said neutral operating position.
39. The wheelchair suspension of claim 38 wherein the at least one caster pivot arm is mounted to the frame at a second pivot axis and said drive assembly pivot arm intersects the at least one front caster pivot arm at a position that is spaced apart from said second pivot axis when viewed from the side when the wheelchair is in said neutral operating position.
40. A wheelchair comprising:
a frame;
a seat supported by the frame;
a pair of suspension assemblies disposed on opposite sides of the frame, each suspension assembly comprising:
a drive assembly pivot arm pivotally connected to the frame;
a drive assembly mounted to the drive assembly pivot arm;
at least one caster pivot arm pivotally mounted to the frame and coupled to the drive assembly pivot arm;
a front caster coupled to the at least one front caster pivot arm;
wherein the drive assembly pivot arm such that the drive assembly pivot arm intersects the at least one front caster pivot arm when viewed from the side when the wheelchair is in a neutral operating position and the at least one caster pivot arm are disposed in a crossed configuration.
41. The wheelchair of claim 40 further comprising at least one rear caster coupled to the frame.
42. The wheelchair of claim 40 wherein the drive assembly pivot arm is pivotally mounted to the frame at a first pivot axis and at least one caster pivot arm is pivotally mounted to the frame at a second pivot axis and the first pivot axis is in front of the second pivot axis on the frame.
43. The wheelchair of claim 40 wherein the drive assembly and the at least one front caster pivot arm are coupled by a variable length member.
44. The wheelchair of claim 43 wherein the variable length member has a maximum length and is compressible from the maximum length to a shorter length.
45. The wheelchair of claim 44 wherein pulling of the variable member when the variable length member is at the maximum length pulls the at least one front caster pivot arm to move the front caster away from the support surface.
46. The wheelchair of claim 43 wherein variable length member is a shock absorber.
47. The wheelchair of claim 43 wherein the variable length member comprises a spring.
48. The wheelchair suspension of claim 43 wherein the drive assembly pivot arm is pivotally connected to the frame at a first pivot axis and the at least one front caster pivot arm comprises first a first caster pivot arm pivotally coupled to the frame at a second pivot axis and second front caster pivot arm pivotally coupled to the frame at a third pivot axis.
49. The wheelchair suspension of claim 48 wherein the first pivot axis is in front of the second pivot axis and the third pivot axis on the frame.
50. The wheelchair of claim 40 wherein the drive assembly and the at least one front caster pivot arm are coupled by a length of flexible material.
51. The wheelchair suspension of claim 40 wherein the drive assembly pivot arm is pivotally mounted to the frame at a first pivot axis and said drive assembly pivot arm intersects the at least one front caster pivot arm at a position that is spaced apart from said first pivot axis when viewed from the side when the wheelchair is in said neutral operating position.
52. The wheelchair suspension of claim 51 wherein the at least one caster pivot arm is mounted to the frame at a second pivot axis and said drive assembly pivot arm intersects the at least one front caster pivot arm at a position that is spaced apart from said second pivot axis when viewed from the side when the wheelchair is in said neutral operating position.