Draper header with automatic reel to cutter bar clearance

A draper header for use in a field to harvest agricultural crops, the draper header comprising:

• a header frame with a front portion and a rear portion each extending laterally between opposite ends thereof, the header frame divided into a plurality of header frame sections pivotable upwardly and downwardly relative to each other for contouring to the field;
• a cutter bar assembly extending across the front portion of the header frame and flexible with the plurality of header frame sections for cutting the crops to be harvested;
• a plurality of reel support arms pivotally coupled to the rear portion of the header frame and extending generally above the front portion of the header frame;
• at least one crop pick-up reel rotatably supported by the plurality of reel support arms and positioned generally above the cutter bar assembly for engaging the crops to be harvested;
• a reel height position sensor for determining a distance between the at least one crop pick-up reel and the cutter bar assembly;
• a wing sensing system operatively coupled to the header frame for sensing pivoting of the plurality of header frame sections relative to each other;
• and
• a hydraulic system adapted for raising and lowering the plurality of reel support arms,
• wherein the hydraulic system is actuated to raise the at least one crop pick-up reel when the wing sensing system detects that one of the plurality of header frame sections pivots downwardly relative to another of the plurality of header frame sections for preventing contact of the at least one crop pick-up reel with the cutter bar assembly;
• wherein the wing sensing system detects a pivot angle of each of the plurality of header frame sections relative to the other of the plurality of header frame sections, and wherein the hydraulic system is actuated to raise the at least one crop pick-up reel when the wing sensing system detects that one of the plurality of header frame sections pivots downwardly past a predetermined maximum pivot angle relative to another of the plurality header frame sections;
• and
• wherein the hydraulic system is prevented from raising and lowering the at least one crop pick-up reel in response to pivoting of the plurality of header frame sections past the predetermined maximum pivot angle when the distance between the at least one crop pick-up reel and the cutter bar assembly is at least a predetermined minimum distance in which the cutter bar assembly can flex with the plurality of header frame sections without contacting the at least one crop pick-up reel.