SHORT TURN RADIUS STEERING SYSTEM

• US 20130249179A1
• Filed: 12/28/2010
• Published: 09/26/2013
• Est. Priority Date: 12/28/2010
• Status: Active Grant

• Current Assignee: Husqvarna AB (HUSQVARNA)
• Original Assignee: Husqvarna Consumer Outdoor Products Na Incorporated (HUSQVARNA)
• Inventors: Burns, Duncan Jr.
• Granted Patent: US 8,882,119 B2
• Time in Patent Office: Days
• US Class Current: 280/93.504
• CPC Class Codes: B62D 3/02 mechanical
• CPC Class Codes: B62D 7/08 the pivotal axes being situated in a single plane transverse to the longitudinal centre line of the vehicle
• CPC Class Codes: B62D 7/16 Arrangement of linkage connections pivots per se F16C

Abstract

To reduce the complexity, maintenance, and cost, and to increase the reliability of a riding lawnmower employing a short turn radius steering system, the riding lawn mower may be configured with a linkage and steering assembly that eliminates or reduces complicated gearing. A riding lawn mower may comprise a link system, pivot brackets, and spindle assemblies. The geometry of the steering system may be configured to provide a turn radius of seven inches or less. Moreover, the geometry of the steering system may be configured to provide Ackerman steering, such that, the inside wheel turns sharper than the outside wheel in a turn.

Claims

1. A short turn radius steering system, comprising:

a linkage configured to move in a first direction;

a pivot bracket coupled to the linkage;

a bracket linkage configured to move in a second direction and coupled to the pivot bracket; and

a spindle assembly coupled to the pivot bracket.

2. The system of claim 1, further comprising an axle, wherein the pivot bracket is configured to rotatably couple to the axle.

3. The system of claim 2, further comprising a pivot bolt, wherein the pivot bolt comprises a rotating surface and an engagement, wherein the rotating surface is configured to support the pivot bracket and the engagement couples to the axle.

4. The system of claim 3, wherein the pivot bolt defines a hollow cavity along a centerline of the pivot bolt and a cross passage perpendicular to the centerline.

5. The system of claim 4, wherein the hollow cavity is configured to receive a lubricant.

6. The system of claim 1, wherein the spindle assembly comprises a spindle arm and a pitman arm, and wherein the pivot bracket is configured to conduct a force from the linkage to the pitman arm, which causes the spindle to move.

7. The system of claim 6, further comprising a wheel coupled to the spindle.

8. The system of claim 7, wherein the pitman arm comprises a tab that is configured to restrict the wheel from turning more than 90 degrees in one direction.

9. The system of claim 1, wherein the steering system is configured to provide a turn radius of approximately 5 inches.

10. A riding lawnmower, comprising:

a steering system, comprising;

a first steering linkage;

a first pivot bracket coupled to the first steering linkage; and

a first spindle assembly coupled to the first pivot bracket, wherein the first linkage is configured to move in a first direction causing the pivot bracket to apply a force to the spindle in a second direction;

an axle, wherein the steering system is operatively coupled to the axle; and

a first wheel rotatably coupled to the first spindle assembly.

11. The lawnmower of claim 10, further comprising a user input coupled to the first steering linkage, wherein the user input is configured to provide inputs to the steering system.

12. The lawnmower of claim 10, wherein the first spindle assembly comprises a first spindle arm and a first pitman arm.

13. The lawnmower of claim 12, wherein the first pitman arm comprises a tab that is configured to contact the axle to restrict the first wheel from turning more than 90 degrees in one direction.

14. The lawnmower of claim 10, wherein the axle comprises a lubricating system that is configured to provide a lubricant to the spindle assembly to reduce at least one of wear and contamination.

15. The lawnmower of claim 10, wherein the steering system further comprises:

a second steering linkage;

a second pivot bracket coupled to the second steering linkage; and

a second spindle assembly coupled to the second pivot bracket.

16. The lawnmower of claim 15, further comprising a second wheel rotatably coupled to the second spindle assembly, wherein the second spindle assembly causes the second wheel to turn sharper than the first wheel.

17. The lawnmower of claim 10, wherein the steering system further comprises a first pivot bolt configured to rotatably couple the first pivot bracket to the axle, wherein the pivot bolt is configured to receive a lubricant to reduce at least one of wear and contamination between the first bolt and the first pivot bracket.

18. A method for operating a lawnmower comprising:

receiving an input at a user input, wherein the input is translated from the user input to a first linkage and a second linkage, wherein a steering system comprises the first linkage, a first pivot bracket, a first spindle assembly, the second linkage, a second pivot bracket, and a second spindle assembly, wherein the first linkage is coupled to the first pivot bracket and the first pivot bracket is coupled to the first spindle assembly, and wherein the second linkage is coupled to the second pivot bracket and the second pivot bracket is coupled to the second spindle assembly;

turning a first wheel in response to the input, wherein the input is provided from the first linkage through the first pivot bracket to the first spindle assembly, and wherein the first wheel is coupled to the first spindle assembly; and

turning a second wheel in response to the input, wherein the input is provided from the first linkage through the second pivot bracket to the second spindle assembly, wherein the second wheel is coupled to the second spindle assembly.

19. The method of claim 19, wherein the second wheel is turned sharper than the first wheel.

20. The method of claim 19, wherein the second wheel is turned substantially 90 degrees in one direction.