Drive system for walk behind mower

• US 9,730,385 B2
• Filed: 03/14/2013
• Issued: 08/15/2017
• Est. Priority Date: 03/14/2013
• Status: Active Grant

• Current Assignee: Husqvarna AB (HUSQVARNA)
• Original Assignee: Husqvarna AB (HUSQVARNA)
• Inventors: Baker, David J.
• Primary Examiner(s): Fbin-Kovcs, rpd
• Application Number:
  US14/774,281
• Publication Number:
  US 20160029557A1
• Time in Patent Office: 1,615 Days
• Field of Search: 56 116, 56 114
• CPC Class Codes: A01D 2034/6837 Drive connections
• CPC Class Codes: A01D 34/6806 Driving mechanisms for the cutters A01D34/76
• CPC Class Codes: A01D 34/6812 Braking or clutching mechanisms
• CPC Class Codes: A01D 34/69 with motor driven wheels
• CPC Class Codes: A01D 34/824 Handle arrangements

Abstract

A drive system of a lawn mower includes a drive belt, a drive pulley, a drive shaft pulley and an idler pulley. The drive pulley is disposed at a rocking transmission of the lawn mower to transfer drive belt motion to power for a set of wheels of the lawn mower via the rocking transmission when the rocking transmission is engaged. The drive shaft pulley is operably coupled to a drive shaft of the lawn mower to rotate responsive to rotation of the drive shaft. The drive shaft pulley engages the drive belt responsive to engagement of the rocking transmission.

Claims

1. A lawn mower comprising:

a blade housing;

an engine supported at least in part by the blade housing and configured to rotate a drive shaft;

a mobility assembly selectively operably coupled to the engine to provide mobility of the lawn mower responsive at least in part to operation of the engine, wherein the mobility assembly comprises a first set of wheels and second set of wheels; and

a rocking transmission operably coupled to the first set of wheels to provide drive power to the first set of wheels via a drive system responsive to engagement of the rocking transmission,

wherein the drive system comprises;

a drive belt;

a drive pulley disposed at the rocking transmission to transfer drive belt motion to power for the first set of wheels via the rocking transmission when the rocking transmission is in an engaged position;

a drive shaft pulley operably coupled to the drive shaft to rotate responsive to rotation of the drive shaft, the drive shaft pulley engaging the drive belt responsive to the rocking transmission being in the engaged position; and

an idler pulley disposed substantially between the drive pulley and the drive shaft pulley and configured to engage the drive belt when the rocking transmission is in the engaged position, such that a belt wrap around the drive shaft pulley is greater than about 200 degrees and a belt wrap around the drive pulley is greater than about 190 degrees,

wherein the rocking transmission is configured to rotate relative to an axle corresponding to the first set of wheels between the engaged position and the disengaged position, wherein rotation of the rocking transmission to the engaged position causes tension to be applied to the drive belt and rotation of the transmission to the disengaged position releases the tension on the drive belt.

2. The lawn mower of claim 1, wherein a distance between an axis of rotation of the drive shaft pulley and an axis of rotation of the idler pulley is about 2.5 inches to about 3.5 inches.

3. The lawn mower of claim 1, wherein the idler pulley is spaced apart from the drive shaft pulley by a distance that is less than ¼

a distance between the drive shaft pulley and the drive pulley.

4. The lawn mower of claim 1, wherein the idler pulley is disposed to push a first belt run of the drive belt extending between the drive pulley and the drive shaft pulley toward a second belt run of the drive belt extending between the drive shaft pulley and the drive pulley to form a gap between the first and second belt runs.

5. The lawn mower of claim 4, wherein the gap has a length that is less than a thickness of the drive belt.

6. The lawn mower of claim 5, wherein the gap is formed proximate to a belt keeper disposed to extend substantially parallel to the second belt run.

7. The lawn mower of claim 6, wherein the idler pulley is disposed such that a line extending between an axis of rotation of the idler pulley and an end of the belt keeper lies substantially perpendicular to a direction of extension of the belt keeper.

8. The lawn mower of claim 6, wherein a line extending from an axis of rotation of the drive shaft pulley to an end of the belt keeper extends substantially perpendicular to a direction of extension of the belt keeper.

9. The lawn mower of claim 6, wherein the belt keeper has a length of about 2.5 to about 3.5 inches.

10. The lawn mower of claim 6, wherein the belt keeper comprises an extension extending away from the drive shaft pulley at an end of the belt keeper proximate to the drive shaft pulley.

11. The lawn mower of claim 6, wherein rotation of the rocking transmission to the disengaged position pushes the drive belt toward the drive shaft pulley, and wherein the belt keeper and the idler pulley combine to cause the drive belt to expand in belt wrap diameter at a location of the drive belt proximate to the drive shaft pulley and thereby disengage the drive shaft pulley from the drive belt.

12. The lawn mower of claim 4, wherein the drive belt is rotated such that the second belt run provides drive belt to the drive shaft pulley and the first belt run returns drive belt from the drive shaft pulley to the drive pulley via the idler pulley.

13. The lawn mower of claim 1, wherein the rocking transmission is rotated between the engaged position and disengaged position via a remote actuator.

14. The lawn mower of claim 1, wherein the drive belt has belt wrap around the drive shaft pulley of less than about 230 degrees and belt wrap around the drive pulley of less than about 220 degrees.

15. The lawn mower of claim 1, wherein the drive belt has belt wrap around the drive shaft pulley of substantially about 218 degrees and belt wrap around the drive pulley of substantially about 192 degrees.

16. A drive system of a lawn mower, the drive system comprising:

a drive belt;

a drive pulley disposed at a rocking transmission of the lawn mower to transfer drive belt motion to power for a set of wheels of the lawn mower via the rocking transmission when the rocking transmission is in an engaged position;

a drive shaft pulley operably coupled to a drive shaft of the lawn mower to rotate responsive to rotation of the drive shaft, the drive shaft pulley engaging the drive belt responsive to the rocking transmission being in the engaged position; and

an idler pulley disposed substantially between the drive pulley and the drive shaft pulley and configured to engage the drive belt when the rocking transmission is in the engaged position, such that a belt wrap around the drive shaft pulley is greater than about 200 degrees and a belt wrap around the drive pulley is greater than about 190 degrees,

wherein the rocking transmission is configured to rotate relative to an axle corresponding to the set of wheels between the engaged position and the disengaged position, wherein rotation of the rocking transmission to the engaged position causes tension to be applied to the drive belt and rotation of the transmission to the disengaged position releases the tension on the drive belt.

17. The drive system of claim 16, wherein a distance between an axis of rotation of the drive shaft pulley and an axis of rotation of the idler pulley is about 2.5 inches to about 3.5 inches.

18. The drive system of claim 16, wherein the idler pulley is spaced apart from the drive shaft pulley by a distance that is less than ¼

a distance between the drive shaft pulley and the drive pulley.

19. The drive system of claim 16, wherein the idler pulley is disposed to push a first belt run of the drive belt extending between the drive pulley and the drive shaft pulley toward a second belt run of the drive belt extending between the drive shaft pulley and the drive pulley to form a gap between the first and second belt runs.

20. The drive system of claim 19, wherein the gap has a length that is less than a thickness of the drive belt.