Dual sickle knife drive with variable phase angle

Patent metadata

Field	Value
Publication number	US-11596100-B2
Application number	US-201916769098-A
Country	US
Kind code	B2
Filing date	Jan 17, 2019
Priority date	Mar 5, 2018
Publication date	Mar 7, 2023
Grant date	Mar 7, 2023

Abstract

A sickle cutting system is mounted on a header for forward travel over ground having a standing crop thereon and includes a cutter bar with a plurality of knife guards and two sickle bars driven at a phase angle difference where the drive system has a phase difference control component operable to drive the first and second sickle bars at a first phase angle difference typically at or around 180 degrees difference to minimize vibration when no cutting action is occurring and at a second phase angle difference which can be at or around 90 degrees to minimize variations in loading applied to the drive system when the cutting action is taking place.

First claim

The invention claimed is:

1. A crop cutting apparatus comprising:
a frame structure arranged for forward travel over ground having a standing crop thereon;
a cutter bar secured to the frame structure and extending transversely across a front end of said frame structure;
a plurality of knife guards mounted in spaced relation along said cutter bar and projecting forwardly therefrom;
each of said guards having a ledger surface with opposed side edges thereof arranged to provide first and second shearing edges;
a first and a second sickle bar mounted in transversely extending position and being driven for reciprocating movement relative to said knife guards;
the first and second sickle bars each having a plurality of knife blades mounted thereon for movement therewith with each of the knife blades having two side cutting edges which cooperate with said shearing edges of said knife guards;
a drive system driving the first sickle bar through repeated cycles of reciprocating movement and driving the second sickle bar through repeated cycles of reciprocating movement;
wherein the drive system is arranged such that the reciprocating movements of the first and second sickle bars occur at a phase angle difference;
the drive system having a phase difference control component operable to change the phase angle difference between the first and second sickle bars from a first phase angle difference to a second phase angle difference which is different from the first phase angle difference.

2. The crop cutting apparatus according to claim 1 wherein the first phase angle difference is in the range of 160 to 200 degrees—and is employed when the sickle bars are not cutting crop.

3. The crop cutting apparatus according to claim 2 wherein there is provided a control arrangement operable to select the first phase angle difference when conditions of the crop cutting apparatus indicate that no crop is being cut.

4. The crop cutting apparatus according to claim 2 wherein the control apparatus includes a sensor responsive to the presence and absence of crop to be cut.

5. The crop cutting apparatus according to claim 2 wherein the control apparatus includes a sensor responsive to an increase of cutting load on the drive system indicative of crop being cut.

6. The crop cutting apparatus according to claim 2 wherein the control apparatus is operable to select the first phase angle when the apparatus is stationary and/or the cutter bar raised.

7. The crop cutting apparatus according to claim 1 wherein the second phase angle difference is variable.

8. The crop cutting apparatus according to claim 1 wherein the second phase angle difference is in the range 70 to 110 degrees and is employed when the sickle bars are cutting crop.

9. The crop cutting apparatus according to claim 1 wherein the second phase angle difference is variable in response to changes in ground speed or in response to a sensed load applied to the drive system by the first and second sickle bars.

10. The crop cutting apparatus according to claim 9 wherein the drive system comprises a hydraulic circuit including hydraulic motors supplied by one of more pumps and the sensed load to the drive system is detected by changes in the hydraulic circuit.

11. The crop cutting apparatus according to claim 1 wherein the second phase angle difference is employed when the sickle bars are cutting crop and is arranged at a phase angle difference such that, when the first sickle bar is at an angle in the cycle where no cutting is occurring due to the location of the sickle blades relative to the guards, the second sickle bar is at an angle in the cycle where cutting is occurring between one of the two side cutting edges of the blades as they cooperate with said shearing edges of said knife guards, and vice versa.

12. The crop cutting apparatus according to claim 11 wherein the second phase angle difference is arranged such that the first sickle bar has minimum cutting forces applied when the second sickle bar has maximum cutting forces applied and vice versa so as to smooth changes in loading applied to the drive system.

13. The crop cutting apparatus according to claim 1 wherein the drive system includes a first drive component for the first sickle bar and a second component for the second sickle bar and wherein each of the first and second drive components includes a sensing system which generates a plurality of sensor signals for each cycle of reciprocating movement and wherein the phase difference control component is responsive to the sensor signals from both of the first and second drive systems for advancing or retarding one of the first and second drive components.

14. The crop cutting apparatus according to claim 13 wherein the phase difference control component is arranged to count the sensor signals.

15. The crop cutting apparatus according to claim 13 wherein the sensing system comprises a plurality of markers which are arranged to pass a stationary sensor so as to generate a sensing signal for each passing marker.

16. The crop cutting apparatus according to claim 13 wherein the first and second drive system each comprise a respective one of first and second hydraulic motors connected in series, with fluid under pressure being directed from a source of hydraulic fluid under pressure to the first motor, from the first motor to the second motor and from the second motor to drain and wherein the control device comprises a first valve operable to discharge some fluid passing from the source to the first hydraulic motor to the second motor to advance the second motor and a second valve operable to discharge some fluid passing from the first hydraulic motor to the second motor to drain to retard the second motor.

17. The crop cutting apparatus according to claim 1 wherein the drive system includes a first drive component for the first sickle bar and a second component for the second sickle bar and a drive connection coupling the first and second drive components and wherein the drive connection is operable to change the phase angle differences.

18. The crop cutting apparatus according to claim 17 wherein the drive connection comprises a mechanical link.

Assignees

• Macdon Ind Ltd

Inventors

• Dunn James Thomas
• Shearer Bruce Robert

Classifications

• A01D34/38

  fluid · CPC title

• A01D34/006 Primary

  Control or measuring arrangements · CPC title

• A01D34/14

  Knife-bars · CPC title

• A01D34/30

  Driving mechanisms for the cutters · CPC title

• A01D34/135 Primary

  having oppositely movable cooperating knife-bars · CPC title