Load weighing and accumulating system and method

Abstract

A loader includes a lift arm assembly, raised by hydraulic lift cylinders and carrying a load bucket. Alignment members mounted respectively on the loader frame and lift arm assembly, and visible to the loader operator, identify the weigh position of the lift arm assembly. A pressure to voltage transducer is mounted on one lift cylinder, and is connected in a bridge circuit producing a DC voltage output. The bridge circuit output signal, proportional to the bucket load, is fed to an amplifier, whose output is passed to an analog-to-frequency converter producing pulses at a frequency proportional to the bucket load. An electronic clock allows the converter output pulses to pass through an AND gate to a bucket counter which displays the bucket load, and is automatically reset to zero. The converter pulses are passed to an accumulator counter through a second AND gate. The accumulator counter accumulates the weight of several bucket loads which are loaded onto a transport vehicle; and is reset manually after the vehicle is loaded. The method includes the steps: detecting the instantaneous pressure in the hydraulic lift cylinder; converting that instantaneous pressure into an electric analog signal proportional to the instantaneous pressure; adjusting that analog signal to eliminate the component which represents the weight of the empty bucket; amplifying the adjusted analog signal; converting the adjusted analog signal to a frequency signal comprising pulses generated at a frequency proportional to the adjusted analog signal; and passing the frequency signal to a pulse counter, through controlled gate means for counting and displaying pulses representing the instantaneous bucket load. The same pulses are passed to a second counter through the same control gate and through an additional control gate to accumulate pulses representative of successive bucket loads.