Blade and ground speed control system

• US 20050166565A1
• Filed: 03/01/2005
• Published: 08/04/2005
• Est. Priority Date: 02/12/2003
• Status: Active Grant

• Current Assignee: Certified Parts Corporation
• Original Assignee: Tecumseh Power Co (Mueller Industries Incorporated)
• Inventors: Rado, Gordon E., Royzen, Arcady, Adams, G. Michael
• Granted Patent: US 7,275,355 B2
• Time in Patent Office: Days
• US Class Current: 56/14.700
• CPC Class Codes: A01D 2101/00 Lawn-mowers
• CPC Class Codes: A01D 34/006 Control or measuring arrangements
• CPC Class Codes: A01D 34/78 electric

Abstract

A self-propelled mower with blade and ground speed controls. The mower includes a motor with an output shaft and a rotatable cutting blade mounted on a blade shaft. The motor may be an internal combustion engine. A torque transmitting mechanism such as a variable diameter pulley defines a rotational speed ratio between the output shaft and the blade shaft. A transmission is coupled to the output shaft. Sensors provide an electronic control unit with the blade speed, ground speed and engine speed. The ECU may be used to maintain either a desired blade speed or a desired ground speed. To maintain a desired blade speed, the ECU monitors the blade speed and, when the blade speed diverges from the desired speed, adjusts either the rotational speed ratio of the output shaft and blade shaft or the ground speed of the mower to maintain the desired blade speed.

Claims

1-20. -20. (canceled)

21. A method of cutting grass with a lawn cutting machine having a motor with an output shaft, a rotatable cutting blade and a driven shaft with a driven wheel coupled thereto, said output shaft operably coupled to said cutting blade and said driven shaft, said driven wheel engagable with the ground for propelling said machine at a ground speed, said method comprising monitoring the speed of said cutting blade;

and

adjusting one of the speed of said cutting blade and said ground speed to maintain the speed of said cutting blade at a substantially constant blade speed value while simultaneously allowing the ground speed of said machine to vary.

22. The method of claim 21 wherein said motor comprises an internal combustion engine and said method further comprises the step of operating said engine at a substantially constant engine speed.

23. The method of claim 22 wherein said step of operating said engine at a substantially constant speed comprises the use of a mechanical governor to control the engine speed.

24. The method of claim 21 wherein said step of monitoring the speed of said cutting blade comprises producing a blade speed signal representative of the speed of said cutting blade and communicating said blade speed signal to an electronic control unit.

25. The method of claim 21 further comprising the step of monitoring the ground speed of said machine.

26. The method of claim 25 wherein said step of monitoring the ground speed of said machine comprises producing a ground speed signal representative of the ground speed of said machine and communicating said ground speed signal to an electronic control unit.

27. The method of claim 21 wherein adjusting the speed of said cutting blade comprises adjusting the effective diameter of a variable diameter pulley operably disposed between said output shaft and said cutting blade.

28. The method of claim 21 wherein adjusting the ground speed comprises adjusting a continuously variable transmission operably disposed between said output shaft and said driven shaft.

29. A method of cutting grass, said method comprising:

providing a lawn cutting machine having a user-operable input device, a motor with an output shaft, a rotatable cutting blade and a driven shaft with a driven wheel coupled thereto, said output shaft operably coupled to said cutting blade and said driven shaft, said driven wheel engagable with the ground for propelling said machine at a ground speed;

monitoring the speed of said cutting blade;

monitoring the ground speed of said machine; and

selecting one of a quality cut algorithm and a quick cut algorithm based upon a user input and operating said machine in accordance with the selected algorithm wherein operating said machine in accordance with said quality cut algorithm includes adjusting one of the speed of said cutting blade and the ground speed to raise said blade speed when the speed of said cutting blade falls below a predetermined blade speed value and wherein operating said machine in accordance with said quick cut algorithm includes adjusting one of the speed of said cutting blade and the ground speed to raise said ground speed when the ground speed falls below a selected ground speed value.

30. A method of cutting grass, said method comprising:

providing a lawn cutting machine having an internal combustion engine with an engine output shaft, a rotatable cutting blade and a driven shaft with a driven wheel coupled thereto, said engine output shaft operably coupled to said cutting blade and said driven shaft, said driven wheel engagable with the ground for propelling said machine at a ground speed;

operating said engine at a substantially constant engine speed;

monitoring the speed of said cutting blade;

monitoring the ground speed of said machine;

adjusting one of the speed of said cutting blade and said ground speed when one of the speed of said cutting blade and said ground speed falls below a predetermined value without directly adjusting the rotational speed of said engine output shaft.

31. The method of claim 30 wherein said step of operating said engine at a substantially constant engine speed comprises the use of a mechanical governor to control the engine speed.