Apparatus and method to vary the reel speed versus ground speed of an agricultural windrower

1. A method of operation of a reel of an agricultural windrower, comprising steps of:

providing a windrower including a fluid pump in connection with a signal controlled device for controlling a pressurized fluid flow to a reel of a header of the windrower for rotating the reel;

providing a programmable control module in connection with the signal controlled device and operable for outputting control signals thereto having variable signal values for controlling a speed of rotation of the reel; and

wherein the control module is programmed to operate in an automatic mode to automatically control the signal controlled device using a predetermined relationship between the signal values and the speed of rotation of the reel, wherein in the automatic mode the control module is configured to use the predetermined relationship to select a signal value corresponding to a desired reel speed as function of a ground speed of the windrower.

2. The method of claim 1 , wherein the signal controlled device comprises a proportional solenoid controlled valve and the control signals comprise electrical currents and the rotational speeds of the reel are linearly related to the signal values of the electrical currents.

3. The method of claim 1 , wherein the control module is programmed to be selectably operable in a manual mode by operation of an operator operable input device, for outputting control signals to the signal controlled device which are a function of input commands received from the input device.

4. The method of claim 1 , wherein the control module when operating in the automatic mode will control the signal controlled device for rotating the reel at at least a predetermined minimum speed.

5. The method of claim 4 , wherein the predetermined minimum speed comprises a speed previously selected by an operator and inputted to the control module.

6. The method of claim 4 , wherein the predetermined minimum speed comprises a programmed speed value.

7. Apparatus for operating a reel of an agricultural windrower, comprising:

a fluid pump and a signal controlled device operable for controlling a pressurized fluid flow to a reel of a header of the windrower for rotating the reel; and

a programmable control module in connection with the signal controlled device and operable for outputting control signals thereto having variable signal values for controlling a speed of rotation of the reel, wherein the control module is programmed to operate in a selectable automatic mode to automatically control the signal controlled device using a predetermined relationship between the signal values and the speed of rotation of the reel wherein in the automatic mode the control module is configured to use the predetermined relationship to select a signal valued corresponding to a desired reel speed as function of a ground speed of the windrower.

8. Apparatus of claim 7 , wherein the signal controlled device comprises a proportional solenoid controlled valve and the control signals comprise electrical currents and the rotational speeds of the reel are linearly related to the signal values of the electrical currents.

9. Apparatus of claim 7 , wherein the control module is programmed to be selectably operable in a manual mode by operation of an operator operable input device, for outputting control signals to the signal controlled device which are a function of input commands received from the input device.

10. Apparatus of claim 7 , wherein the control module when operating in the automatic mode will control the signal controlled device for rotating the reel at at least a predetermined minimum speed.

11. Apparatus of claim 10 , wherein the predetermined minimum speed comprises a speed previously selected by an operator and inputted to the control module.

12. Apparatus of claim 10 , wherein the predetermined minimum speed comprises a programmed speed value.