1. Field of the Invention
This invention relates to an automatic load measuring device which is able to correct a carrying load measured by one or more automatic load measuring sensors to thereby find the actual load of a vehicle.
2. Background
FIG. 8a is a graphical representation which shows a relationship between a display value, a carrying load, a carrying load pattern respectively obtained when a conventional automatic load measuring device is used. Also, FIGS. 8b and 8c are respectively graphical representations to explain the correction results that are obtained when an inflection point correction is made. Further, FIGS. 8d and 8e are respectively graphical representations to show the correction results that are obtained when the same inflection point correction corrections is used in another carrying load pattern.
The output characteristic of an automatic load measuring sensor used in the automatic load measuring device, as shown in FIG. 8a, generally has an upwardly projecting shape. Also, the automatic load measuring sensor shows output characteristics which are different from each other according to the patterns of the carrying loads of a vehicle such as the uniform carrying load, forwardly biased carrying load, backwardly biased carrying load, right biased carrying load, left biased carrying load, and other similarly biased carrying loads of the vehicle.
Conventionally, in order to correct the influences of the output characteristics of the automatic load measuring sensors and the influences of the carrying load patterns of the vehicle, as shown in FIG. 8b or 8c, there has been used an inflection point correction method.
The term "inflection point correction" means correction in which there is set an arbitrary load value and load values larger or smaller than the thus set load value are multiplied by different coefficients to thereby allow the projecting-shaped output characteristic of the load measuring sensor to approach to a straight line.
However, the inflection point correction method used in the conventional automatic load measuring device is truly able to cope with the carrying load patterns of the vehicle only when a specific type of automatic load measuring sensor is used but, as shown in FIGS. 8d and 8e, when the carrying load of the vehicle is measured by use of the other types of automatic load measuring sensors or when other types of carrying load patterns are measured, the inflection point correction method finds it difficult to correct the load carrying patterns of the vehicle and the output characteristics of the automatic load measuring sensors with high accuracy.