Combine harvester automatic table height control

Abstract

An automatic table height control for a combine harvester including a height sensing assembly and a control system. The height sensing assembly includes a finger support shaft rotatably journaled on the bottom of the table. A spring is provided to rotate the shaft in one direction. A plurality of ground engaging fingers are pivotally connected to the finger support shaft. A lost motion connection is provided to limit rotation of the finger support shaft relative to each finger. An iron vane is attached to one end of the finger support shaft. A pair of proximity switches are mounted on the crop harvesting table adjacent the path of movement of the iron vane. When the vane is close to both proximity switches, they are open. When one of the ground engaging fingers rotates the iron vane away from one proximity switch that switch closes and energizes a relay in the control system that energizes a solenoid on the header height control valve to raise or lower the table. The position of the proximity switches on the table is adjustable to set the height at which the system holds the table above the ground. The control system includes a switch and timer which automatically raise the table for a given period of time when the ground drive is reversed. The control system also includes a latching relay that deenergizes the automatic control when the combine is reversed and energizes the automatic control when the manual height switch is moved to the position for lowering the table.