Yield monitoring system for grain harvesting combine

A test weight monitor for use within a grain harvester comprising

• a container for receiving a predetermined volume of grain,
• the container suspended by a first load cell,
• the first load cell generating a first voltage responsive to the weight of said container,
• a dummy weight of known weight suspended by a second load cell,
• the second load cell generating a second voltage responsive to the weight of the dummy weight,
• a voltmeter coupled to said first load cell and said second load cell to measure the potential difference between said first voltage and said second voltage.

A grain test weight monitor comprising

• a container for receiving a predetermined volume of grain,
• the container suspended by a first load cell,
• the first load cell generating a first output responsive to the weight of said container,
• a dummy weight of known weight suspended by a second load cell,
• the dummy weight equal in weight to the weight of said container added to a known standard test weight of a fixed volume of the grain at market moisture, the fixed volume of the grain at market moisture equal in volume to the predetermined volume of the grain in the container,
• the second load cell generating a second output responsive to the weight of the dummy weight,
• a comparator coupled to said first load cell and said second load cell to measure the difference between said first output and said second output.

A method to determine the test weight of grain moving through a grain harvester comprising the steps of:

• filling a container with a known volume of grain from a clean grain elevator in the harvester,
• suspending the container from a first load cell, the first load cell generating a first output responsive to the weight of said container filled with grain,
• suspending a dummy weight from a second load cell, the dummy weight equal in weight to the weight of said container added to a known standard test weight of a fixed volume of the grain at market moisture, the fixed volume of the grain at market moisture equal in volume to the known volume of the grain in the container,
• the second load cell generating a second output responsive to the weight of the dummy weight,
• comparing the second output to the first output to determine a difference,
• calculating the test weight of the sample of grain of known volume from the difference between the second output and the first output.