Agricultural implement with stabilizers

1 . An agricultural apparatus comprising:

a sub-frame;

a transversely extending main frame having a weight, said main frame being inter-connected to said sub-frame,

a stabilizer apparatus inter-connected to said main frame and transversely spaced outwards from said sub-frame, said stabilizer apparatus operable to provide support for said main frame against downward acting forces acting upon said main frame in an operational mode;

wherein

said sub-frame is operable to support a first portion of said weight of said main frame in said operational mode;

said stabilizer apparatus comprises a stabilizer gas actuator device, and wherein said stabilizer apparatus is operable to support a second portion of said weight of said main frame in said operational mode;

wherein said stabilizer gas actuator device is part of a pneumatic system, and wherein said pneumatic system further comprises a frame gas suspension mechanism, and wherein said frame gas suspension mechanism is operable to at least partly provide suspension of said main frame on said sub-frame.

2 . An agricultural apparatus as claimed in claim 1 wherein said stabilizer gas actuator device is operable to provide a force spring rate dependent upon an initial set up gas pressure of said stabilizer gas actuator device.

3 . An agricultural apparatus as claimed in claim 2 wherein the initial set up gas pressure of said stabilizer gas actuator device can be varied to vary the spring rate.

4 . An agricultural apparatus as claimed in claim 2 , wherein the initial set up gas pressure of said stabilizer gas actuator device can be varied to vary an initial resistance force.

5 . An agricultural apparatus as claimed in claim 2 , wherein an internal gas pressure of said stabilizer gas actuator device can be varied to vary the force spring rate between a first initial set up gas pressure of a first operational mode of the agricultural apparatus and a second initial set up gas pressure of a second operational mode of the agricultural apparatus.

6 . An agricultural apparatus as claimed in claim 5 , wherein the first operational mode of the agricultural apparatus is a rigid mode.

7 . An agricultural apparatus as claimed in claim 6 , wherein the second operational mode of the agricultural apparatus is a flex mode.

8 . An agricultural apparatus as claimed in claim 1 , wherein said stabilizer gas actuator device is also operable to provide isolation of vibrations between said stabilizer apparatus and said main frame.

9 . An agricultural apparatus as claimed in claim 1 , wherein said stabilizer apparatus further comprises a stabilizer ground contact device configured to contact a ground surface.

10 . An agricultural apparatus as claimed in claim 9 , wherein said stabilizer ground contact device comprises a gauge wheel.

11 . An agricultural apparatus as claimed in claim 9 , wherein said stabilizer apparatus is mounted to said main frame, and wherein said stabilizer ground contact device is operable in response to an upward rise in a level of the ground, to compress the stabilizer gas actuator device, to increase the pressure within the stabilizer gas actuator device.

12 . An agricultural apparatus as claimed in claim 1 , wherein:

said stabilizer apparatus is a first stabilizer apparatus mounted on a first side of said main frame and operable to provide support for said main frame to oppose downward acting forces acting upon said first side of said main frame;

a pneumatic system comprising:

at least one frame gas suspension bag operationally located between said sub-frame and said main frame on said first side of said main frame;

at least one stabilizer gas bag located proximate said first stabilizer apparatus in pneumatic communication for delivery of pressurized gas with said at least one frame gas suspension bag on said first side of said main frame;

wherein said agricultural apparatus comprises a second stabilizer apparatus mounted on said main frame and transversely spaced from said sub-frame and on an opposite second side of said sub-frame to said first stabilizer apparatus, said second stabilizer apparatus operable to provide support for said main frame to oppose downward acting forces acting upon said second side of said main frame;

wherein said pneumatic system further comprises:

at least one frame gas suspension bag operationally located between said sub-frame and said main frame on said second side of said main frame;

at least one stabilizer gas bag located proximate said second stabilizer apparatus; said at least one stabilizer gas bag that is proximate said second stabilizer apparatus being in pneumatic communication for delivery of pressurized gas with said at least one frame gas suspension bag on said second side of said main frame;

wherein during operation, when said at least one gas suspension bag on said second side of said frame is filled with a volume of a pressurized gas, and said second stabilizer apparatus is subjected to an upwardly directed force, said at least one stabilizer gas bag on said second side of said frame is compressed increasing a pressure of the pressurized gas within the at least one stabilizer gas bag on said second side of said frame, and wherein pressurized gas in said second stabilizer apparatus is communicated to said at least one frame gas suspension bag on said second side of said frame, to increase a gas pressure within said at least one frame gas suspension bag on said second side of side frame, which creates a lifting force to cause said main frame to tilt upwards in a second tilting direction, relative to said sub-frame, said second tilting direction being opposite to said first tilting direction.

13 . An agricultural apparatus as claimed in claim 1 , wherein said frame gas suspension mechanism comprises a frame gas suspension actuator device, and wherein said frame gas suspension actuator device is in pneumatic communication with said stabilizer gas actuator device.

14 . An agricultural apparatus as claimed in claim 13 , wherein said pneumatic system further comprises a gas compressor which is operable to simultaneously pressurize both said frame gas suspension actuator device and said stabilizer gas actuator device to the same initial set up gas pressure level.

15 . An agricultural apparatus as claimed in claim 14 , wherein said pneumatic system further comprises an isolation valve, said isolation valve operable in a first state in which said gas compressor can deliver pressurized gas to simultaneously pressurize both said frame gas suspension actuator device and said stabilizer gas actuator device to the same initial set up gas pressure level and a second state in which the frame suspension gas actuator device and said stabilizer gas actuator device are isolated from said gas compressor.

16 . An agricultural apparatus as claimed in claim 15 , wherein said pneumatic system further comprises a plurality of transversely spaced cutter bar gas actuator devices, and wherein when said isolation valve is in said first state said gas compressor can deliver pressurized gas to simultaneously pressurize said frame gas suspension actuator device, said stabilizer gas actuator device and said cutter bar gas actuator devices, and wherein when said isolation valve is in said second state in which the frame gas suspension actuator device and said stabilizer gas actuator device are isolated from said gas compressor and said cutter bar actuator devices.

17 . An agricultural apparatus as claimed in claim 16 , wherein when said isolation valve is in said first state said gas compressor can deliver pressurized gas to simultaneously pressurize said frame gas suspension actuator device, said stabilizer gas actuator device and said cutter bar gas actuator devices to the same initial set up gas pressure level.

18 . An agricultural apparatus as claimed in claim 13 , wherein:

said frame gas suspension actuator device is operationally located between said sub-frame and said main frame;

said stabilizer gas actuator device is located proximate said stabilizer apparatus; and said stabilizer gas actuator device is in pneumatic communication for delivery of pressurized gas to said frame gas suspension actuator device;

wherein during operation, when said stabilizer gas actuator device is filled with pressurized gas, and said stabilizer apparatus is subjected to an upwardly directed force, said stabilizer gas actuator device is compressed increasing the pressure of the pressurized gas within the stabilizer gas actuator device, and wherein the increase in pressure of the pressurized gas in said stabilizer gas actuator device is communicated towards said frame gas suspension actuator device, to increase the gas pressure within said frame gas suspension actuator device, and thereby create a lifting force on said main frame, to cause said main frame to lift upwards relative to said sub-frame.

19 . An agricultural apparatus as claimed in claim 18 , wherein when the increase in pressure of the pressurized gas in said stabilizer gas actuator device is communicated towards said frame gas suspension actuator device, to increase the gas pressure within said frame gas suspension actuator device, and thereby create a lifting force on said main frame, this causes said main frame to laterally tilt relative to said sub-frame.

20 . An agricultural apparatus as claimed in claim 1 , wherein said stabilizer gas actuator device is an air bag.

21 . An agricultural apparatus as claimed in claim 13 , wherein said frame gas suspension actuator device is an air bag.

22 . An agricultural apparatus as claimed in claim 1 , further comprising a cutter bar assembly mounted on said main frame.

23 . An agricultural apparatus as claimed in claim 1 , further comprising a draper deck assembly mounted on said main frame.

24 . An agricultural apparatus as claimed in claim 1 , further comprising a propulsion unit mounted and configured for supporting said sub-frame.

25 . An agricultural apparatus as claimed in claim 24 , wherein said propulsion unit comprises a header height control mechanism operable to adjust the height and tilt of the sub-frame and main frame relative to the propulsion unit.

26 . An agricultural apparatus as claimed in claim 25 , wherein said header height control mechanism comprises at least one hydraulic cylinder operable to adjust a position of the sub-frame and main frame relative to the propulsion unit.

27 . An agricultural apparatus as claimed in claim 26 , wherein said at least one hydraulic cylinder is operable to adjust the tilt of the sub-frame and main frame relative to the propulsion unit.

28 . An agricultural apparatus as claimed in claim 1 , wherein said main frame is pivotally mounted to said sub-frame to enable lateral tilting of said main frame relative to said sub-frame.

29 . An agricultural apparatus as claimed in claim 1 , wherein gas of the stabilizer gas actuator device is air.

30 . An agricultural apparatus comprising:

a propulsion unit;

a transversely extending main frame having a weight;

a stabilizer apparatus comprising a stabilizer gas actuator device, said stabilizer apparatus being inter-connected to said main frame and transversely spaced outwards from a centerline of said main frame, said stabilizer apparatus operable to provide support for said main frame against downward acting forces acting upon said main frame in an operational mode;

wherein:

said propulsion unit is operable to support a first portion of said weight of said main frame in said operational mode;

said stabilizer apparatus is operable to support a second portion of said weight of said main frame in said operational mode;

said stabilizer gas actuator device is part of a pneumatic system, and wherein said pneumatic system further comprises a frame gas suspension mechanism, and wherein said frame gas suspension mechanism is operable to at least partly provide suspension of said main frame; and

said frame gas suspension mechanism comprises a frame gas suspension actuator device, and wherein said frame gas suspension actuator device is in pneumatic communication with said stabilizer gas actuator device.

31 . An agricultural apparatus as claimed in claim 30 , wherein when an increase in pressure of the pressurized gas in said stabilizer gas actuator device is communicated towards said frame gas suspension actuator device, to increase the gas pressure within said frame gas suspension actuator device, and thereby create a lifting force on said main frame, this causes said main frame to laterally tilt.

32 . An agricultural apparatus as claimed in claim 30 , wherein said pneumatic system further comprises a gas compressor which is operable to simultaneously pressurize both said frame gas suspension actuator device and said stabilizer gas actuator device to the same initial set up gas pressure level.

33 . An agricultural apparatus as claimed in claim 32 , wherein said pneumatic system further comprises an isolation valve, said isolation valve operable in a first state in which said gas compressor can deliver pressurized gas to simultaneously pressurize both said frame gas suspension actuator device and said stabilizer gas actuator device to the same initial set up gas pressure level and a second state in which the frame gas suspension actuator device and said stabilizer gas actuator device are isolated from said gas compressor.

34 . An agricultural apparatus as claimed in claim 33 , wherein said pneumatic system further comprises a plurality of cutter bar gas actuator devices, and wherein when said isolation valve is in said first state said gas compressor can deliver pressurized gas to simultaneously pressurize said frame gas suspension actuator device, said stabilizer gas actuator device and said cutter bar gas actuator devices to the same initial set up gas pressure level, and wherein when said isolation valve is in said second state in which the frame gas suspension actuator device and said stabilizer gas actuator device are isolated from said gas compressor and said cutter bar actuator devices.

35 . An agricultural apparatus comprising:

a sub-frame;

a transversely extending main frame inter-connected to said sub-frame, said main frame having a centerline and a first side on one side of the centerline and a second side on an opposite side of the centerline, said main frame being configured to be able to lift upwards on said first side relative to said sub-frame when subjected to a lifting force on said first side of the main frame and being configured to be able to lift upwards on said second side relative to said sub-frame when subjected to a lifting force on said second side of the main frame;

a first stabilizer apparatus inter-connected to said main frame on said first side and transversely spaced outwards from said sub-frame, said first stabilizer apparatus operable to provide support for said main frame against downward acting forces acting upon said main frame;

a second stabilizer apparatus inter-connected to said main frame on said second side and transversely spaced outwards from said sub-frame, said second stabilizer apparatus operable to provide support for said main frame against downward acting forces acting upon said main frame;

a pneumatic system comprising:

at least one frame gas suspension bag on said first side and operationally located between said sub-frame and said main frame;

at least one frame gas suspension bag on said second side and operationally located between said sub-frame and said main frame;

at least one stabilizer gas bag on said first side located proximate said first stabilizer apparatus; said at least one stabilizer gas bag on said first side being in pneumatic communication for delivery of pressurized gas to said at least one frame gas suspension bag on said first side;

at least one stabilizer gas bag on said second side located proximate said second stabilizer apparatus; said at least one stabilizer gas bag on said second side being in pneumatic communication for delivery of pressurized gas to said at least one frame gas suspension bag on said second side;

wherein during operation:

when said at least one gas suspension bag on said first side is filled with pressurized gas, and said first stabilizer apparatus is subjected to an upwardly directed force, said at least one stabilizer gas bag on said first side is compressed increasing a pressure of the pressurized gas within the at least one stabilizer gas bag on said first side and wherein pressurized gas in said at least one stabilizer gas bag on said first side is communicated towards said at least one frame gas suspension bag on said first side, to increase the gas pressure within said at least one frame gas suspension bag on said first side, which creates a lifting force on said first side, to cause said main frame to lift upwards on said first side relative to said sub-frame;

when said at least one gas suspension bag on said second side is filled with a volume of a pressurized gas, and said second stabilizer apparatus is subjected to an upwardly directed force, said at least one stabilizer gas bag on said second side is compressed increasing a pressure of the pressurized gas within the at least one stabilizer gas bag on said second side and wherein pressurized gas in said at least one stabilizer gas bag on said second side is communicated towards said at least one frame gas suspension bag on said second side, to increase a gas pressure within said at least one frame gas suspension bag on said second side, which creates a lifting force on said second side, to cause said main frame to lift upwards on said second side relative to said sub-frame.

36 . An agricultural apparatus comprising:

a sub-frame;

a transversely extending main frame inter-connected to said sub-frame, said main frame being configured to be able to tilt upwards on a first side relative to said sub-frame when subjected to a lifting force on said first side of said main frame;

a stabilizer apparatus inter-connected to said main frame and transversely spaced outwards from said sub-frame, said stabilizer apparatus operable to provide support for said main frame against downward acting forces acting upon said main frame;

pneumatic system comprising:

at least one frame gas suspension bag and operable to at least partially suspend said main frame on said sub-frame,

at least one stabilizer gas bag being operatively connected to said stabilizer apparatus, and said at least one stabilizer gas bag being in pneumatic communication of pressurized gas to said at least one frame gas suspension bag;

wherein during operation, when said at least one gas suspension bag is filled with a pressurized gas, and said stabilizer apparatus is subjected to an upwardly directed force, said at least one stabilizer gas bag is compressed increasing a pressure of the pressurized gas within the at least one stabilizer gas bag, and wherein pressurized gas in said stabilizer gas bag is communicated towards said at least one frame gas suspension bag, to increase a gas pressure of pressurized gas within said at least one frame gas suspension bag, which creates a lifting force to cause said main frame to tilt upwards in a first transverse tilting direction relative to said sub-frame.

37 . An agricultural apparatus comprising:

a sub-frame;

a transversely extending main frame inter-connected to said sub-frame, said main frame being configured to be able to move upwards on a transverse first side relative to said sub-frame when subjected to a lifting force on said first side of the main frame;

a stabilizer apparatus inter-connected to said main frame and transversely spaced outwards from said sub-frame, said stabilizer apparatus operable to provide support for said main frame against downward acting forces acting upon said main frame;

a pneumatic system comprising:

at least one frame gas suspension bag operationally located between said sub-frame and said main frame;

at least one stabilizer gas bag located proximate said stabilizer apparatus; said at least one stabilizer gas bag being in pneumatic communication for transmission of pressurized gas to said at least one frame gas suspension bag;

wherein during operation, when said at least one frame gas suspension bag is filled with a pressurized gas, and said stabilizer apparatus is subjected to an upwardly directed force, said at least one stabilizer gas bag is compressed increasing a pressure of the pressurized gas within the at least one stabilizer gas bag, and wherein pressurized gas in said stabilizer gas bag is communicated towards said at least one frame gas suspension bag, to increase a gas pressure within said at least one frame gas suspension bag, which creates a lifting force on the first side of said main frame, to cause said main frame to lift upwards relative to said sub-frame.

38 . An agricultural apparatus as claimed in claim 37 wherein, said lifting force on said first side of said main frame causes said main frame to tilt upwards relative to said sub-frame on said first side of said main frame.

39 . An agricultural apparatus as claimed in claim 37 , wherein during operation, said at least one frame gas suspension bag and said at least one stabilizer gas bag contain pressurized air.

40 . An agricultural apparatus as claimed in claim 37 , wherein said at least one stabilizer gas bag is located on a part of said stabilizer apparatus.

41 . An agricultural apparatus as claimed in claim 40 wherein said at least one stabilizer gas bag is mounted between said stabilizer apparatus and a component of said main frame.

42 . An agricultural apparatus as claimed in claim 37 , wherein said stabilizer apparatus is a gauge wheel assembly and said at least one stabilizer gas bag comprises at least one gauge wheel gas bag.

43 . An agricultural apparatus as claimed in claim 42 wherein said gauge wheel assembly comprises: a gauge wheel mounted for rotation on a wheel hub assembly to provide support for said agricultural apparatus in moving across a ground surface in a rigid mode of operation; a pivot mechanism comprising a pivot arm interconnected to said wheel hub assembly and mounted for pivotal movement to said main frame; wherein said at least one gauge wheel gas bag is mounted between said pivot arm and a component of said main frame, wherein during operation when said at gauge wheel is subjected to an upwardly directed force, said pivot arm pivots upward compressing said at least one gauge wheel gas bag to thereby increase the pressure of the pressurized gas within the at least one gauge wheel gas bag.

44 . An agricultural apparatus as claimed in claim 37 , further comprising a transversely extending cutter bar mounted to said main frame operable to cut crop material.

45 . An agricultural apparatus as claimed in claim 44 , wherein said pneumatic system further comprises a plurality of cutter bar float gas bags spaced transversely along the cutter bar, and wherein said agricultural apparatus further comprises a plurality of pivoting paddle devices each with a pivot mechanism comprising a pivot arm mounted for pivotal movement relative to said main frame; wherein each said cutter bar float gas bag is mounted between said paddle device and a component of said main frame, wherein during a flex mode of operation said plurality of cutter bar float air bags are pressurized to a first pressure such when said cutter bar subjected to an upwardly directed force, said pivot arm pivots upward compressing said cutter bar float gas bag to compress said cutter bar gas bag thereby permitting flexing of said cutter bar in at least a region relative to said main frame.

46 . An agricultural apparatus as claimed in claim 45 , wherein during a rigid mode of operation said plurality of cutter bar float air bags are pressurized by said pneumatic system to a second pressure that is substantially greater than said first pressure such when said cutter bar subjected to an upwardly directed force, said pivot arm is substantially prevented from pivoting upward thereby substantially preventing flexing of said cutter bar relative to said main frame.

47 . An agricultural apparatus as claimed in claim 46 , wherein said plurality of cutter bar float air bags are pneumatically isolated from said at least one frame gas suspension bag and said at least one stabilizer gas bag located when operating in said rigid mode of operation.

48 . An agricultural apparatus as claimed in claim 37 , wherein said pneumatic system further comprises a gas compressor and a working air storage tank which are operable to provide pressurized air to said at least one frame gas suspension bag and said at least one stabilizer gas bag.

49 . An agricultural apparatus as claimed in claim 47 , wherein said pneumatic system further comprises a gas compressor and a working air storage tank which are operable to provide pressurized air to said plurality of cutter bar float gas bags, said at least one frame gas suspension bag and said at least one stabilizer gas bag.

50 . An agricultural apparatus as claimed in claim 49 , further comprising a dump valve device operable to selectively expel air from said at least one frame gas suspension bag and said at least one stabilizer gas bag.

51 . An agricultural apparatus as claimed in claim 48 further comprising a dump valve device operable to selectively expel air from said plurality of cutter bar float gas bags, said at least one frame gas suspension bag and said at least one stabilizer gas bag.

52 . An agricultural apparatus as claimed in claim 45 , further comprising an isolation valve wherein said plurality of cutter bar float air bags may be selectively pneumatically isolated by said isolation valve from said at least one frame gas suspension bag and said at least one stabilizer gas bag located when operating in said rigid mode of operation.

53 . An agricultural apparatus as claimed in claim 37 , further comprising a propulsion unit, and wherein said sub-frame in interconnected to said propulsion unit, and wherein during a rigid mode of operation, said sub-frame and said main frame are at least partially supported by said propulsion unit.

54 . An agricultural apparatus as claimed in claim 53 , further comprising a header height control system that comprises a plurality of height sensors, said header height control system operable to raise and lower said sub-frame and said main frame in response to signals provided by said height sensors.

55 . An agricultural apparatus as claimed in claim 54 wherein said header height control system is operable to transversely tilt said sub-frame and said main frame relative to said propulsion unit in response to signals provided by said height sensors.

56 . An agricultural apparatus comprising:

a sub-frame;

a transversely extending main frame having a weight, said main frame being inter-connected to said sub-frame,

a stabilizer apparatus inter-connected to said main frame and transversely spaced outwards from said sub-frame, said stabilizer apparatus operable to provide support for said main frame against downward acting forces acting upon said main frame in an operational mode;

wherein

said sub-frame is operable to support a first portion of said weight of said main frame in said operational mode;

said stabilizer apparatus comprises a stabilizer gas actuator device, and wherein said stabilizer apparatus is operable to support a second portion of said weight of said main frame in said operational mode;

wherein said main frame is pivotally mounted to said sub-frame to enable lateral tilting of said main frame relative to said sub-frame.

57 . An agricultural apparatus comprising:

a sub-frame;

a transversely extending main frame having a weight, said main frame being inter-connected to said sub-frame,

a stabilizer apparatus inter-connected to said main frame and transversely spaced outwards from said sub-frame, said stabilizer apparatus operable to provide support for said main frame against downward acting forces acting upon said main frame in an operational mode;

wherein

said sub-frame is operable to support a first portion of said weight of said main frame in said operational mode;

said stabilizer apparatus comprises a stabilizer gas actuator device, and wherein said stabilizer apparatus is operable to support a second portion of said weight of said main frame in said operational mode;

wherein:

said stabilizer apparatus is a first stabilizer apparatus mounted on a first side of said main frame and operable to provide support for said main frame to oppose downward acting forces acting upon said first side of said main frame;

a pneumatic system comprising:

at least one frame gas suspension bag operationally located between said sub-frame and said main frame on said first side of said main frame;

at least one stabilizer gas bag located proximate said first stabilizer apparatus in pneumatic communication for delivery of pressurized gas with said at least one frame gas suspension bag on said first side of said main frame;

wherein said agricultural apparatus comprises a second stabilizer apparatus mounted on said main frame and transversely spaced from said sub-frame and on an opposite second side of said sub-frame to said first stabilizer apparatus, said second stabilizer apparatus operable to provide support for said main frame to oppose downward acting forces acting upon said second side of said main frame;

wherein said pneumatic system further comprises:

at least one frame gas suspension bag operationally located between said sub-frame and said main frame on said second side of said main frame;

at least one stabilizer gas bag located proximate said second stabilizer apparatus; said at least one stabilizer gas bag that is proximate said second stabilizer apparatus being in pneumatic communication for delivery of pressurized gas with said at least one frame gas suspension bag on said second side of said main frame;

wherein during operation, when said at least one gas suspension bag on said second side of said frame is filled with a volume of a pressurized gas, and said second stabilizer apparatus is subjected to an upwardly directed force, said at least one stabilizer gas bag on said second side of said frame is compressed increasing a pressure of the pressurized gas within the at least one stabilizer gas bag on said second side of said frame, and wherein pressurized gas in said second stabilizer apparatus is communicated to said at least one frame gas suspension bag on said second side of said frame, to increase a gas pressure within said at least one frame gas suspension bag on said second side of side frame, which creates a lifting force to cause said main frame to tilt upwards in a second tilting direction, relative to said sub-frame, said second tilting direction being opposite to said first tilting direction.

58 . An agricultural apparatus comprising:

a sub-frame;

a transversely extending main frame having a weight, said main frame being inter-connected to said sub-frame,

a stabilizer apparatus inter-connected to said main frame and transversely spaced outwards from said sub-frame, said stabilizer apparatus operable to provide support for said main frame against downward acting forces acting upon said main frame in an operational mode;

wherein

said sub-frame is operable to support a first portion of said weight of said main frame in said operational mode;

said stabilizer apparatus comprises a stabilizer gas actuator device, and wherein said stabilizer apparatus is operable to support a second portion of said weight of said main frame in said operational mode;

wherein the agricultural apparatus further comprises a propulsion unit mounted and configured for supporting said sub-frame, wherein said propulsion unit comprises a header height control mechanism operable to adjust the height and tilt of the sub-frame and main frame relative to the propulsion unit.

59 . An agricultural apparatus as claimed in claim 58 , wherein said header height control mechanism comprises at least one hydraulic cylinder operable to adjust a position of the sub-frame and main frame relative to the propulsion unit.

60 . An agricultural apparatus as claimed in claim 59 , wherein said at least one hydraulic cylinder is operable to adjust the tilt of the sub-frame and main frame relative to the propulsion unit.