Header height control system with multiple potentiometer input

Abstract

A harvesting machine includes a harvesting header with a header frame, a cutterbar assembly attached to the header frame along the length thereof and configured to cut a crop, and a draper assembly positioned behind the cutterbar assembly and operable to receive severed crop material from the cutterbar assembly. The draper assembly includes a center draper that delivers crop material to a feeder house of the harvesting machine and oppositely spaced side drapers that deliver crop material to the center draper. The harvesting header is operable to flex and thereby follow an uneven terrain.

1 . A harvesting header adjustably supported on a crop harvesting machine, wherein the machine has a header height adjustment system for controlling the height of the header relative to the ground, said harvesting header comprising:
 a flexible cutterbar assembly extending lengthwise in a lateral direction relative to the normal direction of travel of the header to present multiple cutterbar assembly sections;   a plurality of laterally spaced apart support arms being attached to and cooperatively supporting the flexible cutterbar assembly, with multiple support arms being associated with each of the cutterbar assembly sections;   said support arms being pivotal about a laterally extending axis so that the flexible cutterbar assembly is operable to flex along the length thereof in response to changes in terrain as the header is advanced along the ground; and   a header height sensing system operable to send a cutterbar position signal to the header height adjustment system of the harvesting machine so that the header height is adjusted when the cutterbar assembly flexes beyond a predetermined position,   said header height sensing system including a plurality of sensors associated with each cutterbar assembly section,   each of the sensors being operably coupled to one of the support arms to sense the angular position thereof and provide an arm position signal corresponding to the position of the cutterbar assembly at the one support arm, wherein a plurality of arm position signals are provided for each cutterbar assembly section,   said header height sensing system including an electrical comparator circuit including sensor inputs operably coupled to receive the arm position signals associated with each cutterbar assembly section and provide a single cutterbar position signal for each cutterbar assembly section.   
   
   
       2 . The harvesting header as claimed in  claim 1 ,
 each of said sensors comprising a potentiometer that is operable to provide a voltage signal,   said sensor inputs being electrically coupled to the to the potentiometers.   
   
   
       3 . The harvesting header as claimed in  claim 2 ,
 said comparator circuit operable to compare the voltage signals associated each cutterbar assembly section and identify the smallest one of the voltage signals in response to the comparison.   
   
   
       4 . The harvesting header as claimed in  claim 3 ,
 said comparator circuit including a plurality of diodes each coupled to a corresponding one of the sensors to receive the voltage signals,   said diodes cooperatively identifying the smallest voltage signal for each cutterbar assembly section.   
   
   
       5 . The harvesting header as claimed in  claim 1 ,
 said comparator circuit providing each cutterbar position signal as an analog output signal.   
   
   
       6 . The harvesting header as claimed in  claim 1 ,
 said comparator circuit including an operational amplifier electrically coupled to the sensor inputs and operable to provide each cutterbar position signal in response to the signals provided by the sensors.   
   
   
       7 . The harvesting header as claimed in  claim 1 ,
 a plurality of said comparator circuits, each being associated with one of the cutterbar assembly sections.   
   
   
       8 . The harvesting header as claimed in  claim 1 ,
 said cutterbar assembly sections comprising a pair of side sections of the cutterbar assembly,   said support arms associated with each side section including a pair of laterally outermost support arms and at least one intermediate support arm located between the outermost support arms, with a sensor being coupled to each of the outermost support arms.   
   
   
       9 . The harvesting header as claimed in  claim 1 ,
 said header height sensing system including linkage extending only between each sensor and the respective one of the support arms to provide direct interconnection therebetween.   
   
   
       10 . The harvesting header as claimed in  claim 1 ; and
 a pair of stops cooperating to define a range of angular movement of the support arms and a corresponding range of generally vertical movement of the flexible cutterbar assembly,   said predetermined position being within the range of generally vertical movement of the cutterbar assembly.   
   
   
       11 . The harvesting header as claimed in  claim 10 ,
 a first one of the stops being positioned to serve as an upper limit of the range of angular movement, thereby restricting upward angular movement of the support arms, and a second one of the stops being positioned to serve as a lower limit of the range of angular movement, thereby restricting downward angular movement of the support arms,   said cutterbar position signal being used to cause raising of the header when the cutterbar position signal corresponds to flexing of the cutterbar assembly above the predetermined position within the range of generally vertical movement.   
   
   
       12 . The harvesting header as claimed in  claim 1 ; and
 a draper assembly supported behind the cutterbar assembly for conveying severed crop materials received from the cutterbar assembly,   said draper assembly including a pair of side drapers, each of which is carried on a plurality of the support arms so as to flex with the cutterbar assembly.