Patent EA-005026-B1 (EA)
Title: Multi-section header with flexible crop cutting knife
Inventor: PATTERSON ROGER L
IPC: A01D57/20
Filed: 2002-05-30
Abstract: 1. A crop harvesting header comprising: a main frame structure extending across a width of the header for movement in a forward direction generally at right angles to the width across ground including a crop to be harvested; a mounting assembly for carrying the main frame structure on a propulsion vehicle; a crop receiving table carried on the main frame structure across the width of the header; a cutter bar across a front of the table arranged to move over the ground in a cutting action and carrying a cutter knife operable for cutting the crop as the header is moved forwardly across the ground for depositing the crop onto the table; a skid element extending across the width of the header for engaging the ground so as to receive lifting forces from the ground at whatever points of the skid element contact the ground tending to lift the cutter bar; a crop transport system on the table for moving the cut crop toward a discharge location of the header; the main frame structure being divided into a first frame portion and a second separate frame portion with the second connected to the first by a pivot coupling arranged for pivotal movement of the second relative to the first about a pivot axis extending in a plane parallel to the forward direction and intersecting the cutter bar so that, as the second pivots relative to the first, the cutter bar bends in the area adjacent the respective pivot axis to accommodate the pivotal movement; the pivot coupling of the second frame portion relative to the first frame portion being arranged such that weight from the second frame portion outboard of the pivot coupling tends to rotate the second frame portion about the pivot coupling in a downward direction; the mounting assembly including a support assembly arranged to provide a total lifting force from the propulsion vehicle acting to support the main frame structure for floating movement relative to the propulsion vehicle such that upward pressure from the ground on the skid element, which is greater than a downward force from a part of the weight of the header unsupported by the lifting force, tends to lift the main frame structure relative to the propulsion vehicle; the support assembly being arranged such that the total lifting force can be varied so that the total downward force, from that part of the weight of the header which is unsupported by the lifting force, can be varied to change the total pressure of the skid element on the ground; the support assembly including a first component arranged to provide a first lifting force for the first frame portion; the support assembly including a second component arranged to provide a second lifting force for the second frame portion; the support assembly being arranged to provide floating movement for each of the first and second frame portions relative to each other and relative to the propulsion vehicle such that upward pressure from the ground on the skid element, which is greater than a downward force from a part of the weight of the header unsupported by the lifting force, tends to lift each of the first and second frame portions relative to the propulsion vehicle; the first and second components being arranged such that the first and second lifting forces vary as the total lifting force is varied and such that the lifting force is balanced across the width of the first and second frame portions. 2. The header according to Claim 1 wherein the first and second components are arranged such that the first and second lifting forces vary proportionally. 3. The header according to Claim 1 wherein the first and second components include a balancing connection which is arranged such that adjustment of the support assembly to effect variation of the total lifting force automatically balances the first and second lifting forces proportionally. 4. The header according to Claim 3 wherein the balancing connection comprises a pivotal balance beam to which is applied as three balanced forces a) said total lifting force from the propulsion vehicle, b) said first lifting force and c) said second lifting force. 5. The header according to Claim 1 wherein the support assembly includes at least one spring which is arranged to provide spring floating movement of the first and second frame portions relative to the propulsion vehicle and relative to each other. 6. The header according to Claim 1 wherein the second component comprises an interconnecting linkage which transfers the outboard weight of the second frame portion to the first frame portion. 7. The header according to Claim 6 wherein the linkage includes a pivotal balance beam to which is applied as three balanced forces a) said lifting force from the propulsion vehicle, b) at least part of the weight from the first frame portion and said weight applied to the first frame portion from the second frame portion at the pivot coupling and c) said outboard weight of the second frame portion. 8. The header according to Claim 7 wherein the balance beam is located at the first frame portion. 9. The header according to Claim 7 wherein the balance beam extends in the forward direction. 10. The header according to Claim 9 wherein the mounting assembly includes a lift arm extending in the forward direction parallel to and underneath the balance beam. 11. The header according to Claim 10 wherein the lift arm is arranged to apply to the balance beam force a) at a position forwardly of force b) which is applied forwardly of force c). 12. The header according to Claim 7 wherein the linkage includes a weight transfer link extending from the second frame portion to the first frame portion at a position above the pivot coupling. 13. The header according to Claim 12 wherein the weight transfer link includes a bell crank on the first frame portion above the balance beam. 14. The header according to Claim 13 wherein the bell crank is adjustable to balance the forces b) and c) to hold the cutter bar straight when the upward pressure from the ground is constant along the cutter bar. 15. The header according to Claim 6 wherein the linkage is a nonspring linkage and the floating movement is provided by at least one spring of the support assembly. 16. The header according to Claim 1 wherein the mounting assembly includes two lift arms each carried on a respective spring and spaced apart across the first portion such that the first portion can float upwardly and can twist about an axis in the forward direction. 17. The header according to Claim 1 wherein each of the portions includes a horizontal main frame beam and wherein the pivot coupling between the second frame portion and the first frame portion is arranged below the main beams. 18. The header according to Claim 1 wherein the pivotal movement between the second frame portion and the first frame portion is less than a total of 6 degrees. 19. The header according to Claim 1 wherein the pivotal movement between the second frame portion and the first frame portion is less than a total of 4 degrees. 20. The header according to Claim 1 wherein the header is unsupported by ground wheels such that all lifting forces from the ground are communicated through said skid element. 21. The header according to Claim 1 wherein there is provided a bottom stop member arranged such that downward floating movement of the header is halted at a bottom position when the header is lifted to a raised position in which the skid element is spaced from the ground so that there is no lifting force from the ground and wherein there is provided a balance mechanism to balance the first and second portions in aligned position so the cutter bar is straight when the header is in the raised position. 22. The header according to Claim 21 wherein the first and second components include a balancing connection which is arranged such that adjustment of the support assembly to effect variation of the total lifting force automatically balances the first and second lifting forces proportionally and wherein the balance mechanism is arranged to apply balance forces from the bottom stop member to the balancing connection.