Wheelchair suspension

• US 9,913,768 B2
• Filed: 04/20/2015
• Issued: 03/13/2018
• Est. Priority Date: 10/09/2009
• Status: Active Grant

• Current Assignee: Invacare Corporation
• Original Assignee: Invacare Corporation
• Inventors: Cuson, Robert L., Bekoscke, Robert A., Stothard, Daniel J.
• Primary Examiner(s): Shriver, II, James A
• Assistant Examiner(s): Coolman, Vaughn
• Application Number:
  US14/690,678
• Publication Number:
  US 20150283010A1
• Time in Patent Office: 1,058 Days
• Field of Search: 280 30, 280 4734, 280 4738, 280 474, 280 4741, 2802501, 180 651, 180 6551, 180 656, 180 6531
• CPC Class Codes: A61G 5/04 motor-driven A61G5/06 takes precedence; motor-operated rests A61G5/12; for vehicles with handlebars, equipped with three or more wheels B62K5/003, B62K5/023
• CPC Class Codes: A61G 5/042 Front wheel drive
• CPC Class Codes: A61G 5/043 Mid wheel drive
• CPC Class Codes: A61G 5/06 with obstacle mounting facilities, e.g. for climbing stairs, kerbs or steps
• CPC Class Codes: A61G 5/10 Parts, details or accessories
• CPC Class Codes: A61G 5/1078 with shock absorbers or other suspension arrangements between wheels and frame
• CPC Class Codes: A61G 5/1089 Anti-tip devices
• CPC Class Codes: B60G 2300/24 Wheelchairs
• CPC Class Codes: Y10S 180/907 Motorized wheelchairs

Abstract

A wheelchair suspension assembly includes a frame, a drive assembly, an anti-tip linkage, a front anti-tip wheel, and a rear anti-tip wheel. The drive assembly includes a drive wheel. The front anti-tip wheel is positioned forward of the drive wheel by the anti-tip linkage. The rear anti-tip wheel is positioned rearward of the drive wheel the anti-tip linkage. The anti-tip linkage couples the front anti-tip wheel to the rear anti-tip wheel such that upward movement of the front anti-tip wheel relative to the frame causes upward movement of the rear anti-tip wheel relative to the frame. The anti-tip linkage includes a front anti-tip pivot arm that is pivotally coupled to the frame, a rear anti-tip pivot arm that is pivotally coupled to the frame, and a connecting link that couples the front anti-tip pivot arm and the rear anti-tip pivot arm.

Claims

1. A wheelchair comprising:

a frame;

first and second drive assemblies that each include a drive wheel;

first and second suspension assemblies that each include an anti-tip linkage and a shock absorber with a spring return;

first and second front anti-tip wheels positioned forward of the drive wheels by the first and second anti-tip linkages;

first and second rear anti-tip wheels positioned rearward of the drive wheels by the first and second anti-tip linkages;

the first anti-tip linkage couples the first front anti-tip wheel to the first rear anti-tip wheel such that upward movement of the first front anti-tip wheel relative to the frame causes upward movement of the first rear anti-tip wheel relative to the frame, wherein the first anti-tip linkage includes a first rigid front anti-tip pivot arm that is pivotally coupled to the frame, a first rigid rear anti-tip pivot arm that is pivotally coupled to the frame, and a first rigid connecting link that couples the first rigid front anti-tip pivot arm and the first rigid rear anti-tip pivot arm;

wherein the first shock absorber with spring return is directly coupled to the first rigid rear anti-tip pivot arm and is directly coupled to the frame to bias the first rigid rear anti-tip pivot arm downward relative to the frame;

the second anti-tip linkage couples the second front anti-tip wheel to the second rear anti-tip wheel such that upward movement of the second front anti-tip wheel relative to the frame causes upward movement of the second rear anti-tip wheel relative to the frame, wherein the second anti-tip linkage includes a second rigid front anti-tip pivot arm that is pivotally coupled to the frame, a second rigid rear anti-tip pivot arm that is pivotally coupled to the frame, and a second rigid connecting link that couples the second rigid front anti-tip pivot arm and the second rigid rear anti-tip pivot arm;

wherein the second shock absorber with spring return is directly coupled to the second rigid rear anti-tip pivot arm and is directly coupled to the frame to bias the second rigid rear anti-tip pivot arm downward relative to the frame;

wherein the first drive assembly is pivotally coupled to the frame at a first drive assembly pivot axis that is forward of an axis of rotation of the drive wheel of the first drive assembly;

wherein the first drive assembly is biased downward relative to the frame by a first drive assembly biasing spring that is coupled to the frame;

wherein the second drive assembly is pivotally coupled to the frame at a second drive assembly pivot axis that is forward of an axis of rotation of the drive wheel of the second drive assembly; and

wherein the second drive assembly is biased downward relative to the frame by a second drive assembly biasing spring that is coupled to the frame.

2. The wheelchair of claim 1 wherein the first rigid connecting link is pivotally connected to the first rigid front anti-tip pivot arm and the first rigid rear anti-tip pivot arm and the second rigid connecting link is pivotally connected to the second rigid front anti-tip pivot arm and the second rigid rear anti-tip pivot arm.

3. A wheelchair suspension assembly comprising:

a frame;

a drive assembly that includes a drive wheel;

an anti-tip linkage;

an anti-tip linkage spring;

a front anti-tip wheel positioned forward of the drive wheel by the anti-tip linkage;

a rear anti-tip wheel positioned rearward of the drive wheel the anti-tip linkage;

wherein the anti-tip linkage couples the front anti-tip wheel to the rear anti-tip wheel such that upward movement of the front anti-tip wheel relative to the frame causes upward movement of the rear anti-tip wheel relative to the frame;

wherein the anti-tip linkage includes a front anti-tip pivot arm that is pivotally coupled to the frame, a rear anti-tip pivot arm that is pivotally coupled to the frame, and a connecting link that couples the front anti-tip pivot arm and the rear anti-tip pivot arm;

wherein the anti-tip linkage spring is directly coupled to the rear anti-tip pivot will and is directly coupled to the frame to bias the rear anti-tip pivot arm downward relative to the frame; and

wherein the drive assembly is pivotally coupled to the frame at a first drive assembly pivot axis.

4. The wheelchair suspension assembly of claim 3 wherein the anti-tip linkage spring comprises a shock absorber with a spring return.

5. The wheelchair suspension assembly of claim 3 wherein the front anti-tip pivot arm is rigid.

6. The wheelchair suspension assembly of claim 3 wherein the rear anti-tip pivot arm is rigid.

7. The wheelchair suspension assembly of claim 3 wherein the connecting link is rigid.

8. The wheelchair suspension assembly of claim 3 wherein the drive assembly pivot axis is forward of the axis of rotation of the drive wheel.

9. The wheelchair suspension assembly of claim 3 wherein the drive assembly is biased downward relative to the frame by a drive assembly biasing spring.

10. The wheelchair suspension assembly of claim 3 wherein the connecting link is pivotally connected to the front anti-tip pivot arm and the rear anti-tip pivot arm.