Apparatus for measuring load of construction machine

Abstract

A load measuring device for a construction machine includes a processing unit for acquiring signals indicative of cylinder pressure of front and rear suspension cylinders via pressure sensors and computing a weight value of a load put on a dump body of the construction machine. When the construction machine is traveling on a curvilinear route, the construction machine makes the output of the weight value ineffective. In particular, when the differential speed value between the rear wheels, received from a speed difference detector, is below a preset value, the arithmetic unit outputs a loading weight W computed by the processing unit, as final loading weight, and so that when the differential speed exceeds the preset value, the arithmetic unit makes ineffective the computed loading weight W as the final loading weight output.

What is claimed is: 
     
         1 . An apparatus for measuring a load of a construction machine, the apparatus including a processing unit for acquiring signals indicative of cylinder pressure of front and rear suspension cylinders via respective pressure sensors and computing a weight value of a load put on a dump body of the construction machine, the apparatus comprising:
 steering angle detectors each for detecting a steering angle of a left or right front wheel on the construction machine; and   a final loading-weight confirmation element with a final-confirmation arithmetic unit adapted such that when the steering angle values from the steering angle detectors are the same as a preset value, the arithmetic unit outputs the loading weight W computed by the processing unit, as final loading weight, and such that when the steering angle values exceed the preset value, the arithmetic unit makes ineffective the computed loading weight W as the final loading weight output.   
     
     
         2 . The apparatus for measuring a load carried by a construction machine according to  claim 1 , the apparatus further comprising:
 a vehicle chassis speed detector for detecting a speed of the vehicle chassis;   a loading-weight-W fluctuation range measuring unit for measuring a fluctuation range of the loading weight value W sent from the processing unit, by repeating a sampling measurement operation several times within a definite time; and   a loading-weight minimum fluctuation range confirmation unit for calculating an average value of the data measurements sent from the loading-weight-W fluctuation range measuring unit, and then confirming whether or not a difference between a maximum measured value and a minimum measured value has become a minimum allowed for the average value;   wherein the final-confirmation arithmetic unit is configured such that when condition 1 under which the speed of the vehicle chassis from the vehicle chassis speed detector exceeds a preset value, condition 2 under which the loading weight value from the loading-weight minimum fluctuation range confirmation unit is within a minimum fluctuation range, and condition 3 under which the steering angle values from the steering angle detectors are the same as a preset value, are all satisfied, the arithmetic unit outputs the loading weight W computed by the processing unit, as final loading weight, and such that when at least one of the three conditions is not satisfied, the arithmetic unit makes ineffective the computed loading weight W as the final loading weight output.   
     
     
         3 . The apparatus for measuring a load carried by a construction machine according to  claim 2 ,
 wherein the final-confirmation arithmetic unit in the final loading-weight confirmation element further includes the procedure of sampling the vehicle chassis speed from the vehicle chassis speed detector several times and then after processing an average value of the samplings, when any speed changes occurring within several seconds are within the preset value, handling condition 1 as satisfied.   
     
     
         4 . An apparatus for measuring a load of a construction machine, the apparatus including a processing unit for acquiring signals indicative of cylinder pressure of front and rear suspension cylinders via respective pressure sensors and computing a weight value of a load put on a dump body of the construction machine, the apparatus comprising:
 steering angle detecting device for detecting a steering angle of front wheels on the construction machine; and   a final loading-weight confirmation element with a final-confirmation arithmetic unit adapted such that when the steering angle values from the steering angle detecting device are the same as a preset value, the arithmetic unit outputs the loading weight W computed by the processing unit, as final loading weight, and such that when the steering angle values exceed the preset value, the arithmetic unit makes ineffective the computed loading weight W as the final loading weight output.   
     
     
         5 . An apparatus for measuring a load of a construction machine, the apparatus including a processing unit for acquiring signals indicative of cylinder pressure of front and rear suspension cylinders via respective pressure sensors and computing a weight value of a load put on a dump body of the construction machine, the apparatus comprising:
 a diagnostic device for judging the construction machine whether traveling on a rectilinear route; and   a final loading-weight confirmation element with a final-confirmation arithmetic unit adapted such that when the diagnostic device judges the construction machine traveling on a rectilinear route, the arithmetic unit outputs the loading weight W computed by the processing unit, as final loading weight, and such that when the diagnostic device judges the construction machine traveling on the curvilinear route, the arithmetic unit makes ineffective the computed loading weight W as the final loading weight output.   
     
     
         6 . The apparatus for measuring a load of a construction machine according to  claim 1 ,
 wherein the construction machine is a dump truck for transporting the load on the dump body from one place to another.   
     
     
         7 . The apparatus for measuring a load of a construction machine according to  claim 2 ,
 wherein the construction machine is a dump truck for transporting the load on the dump body from one place to another.   
     
     
         8 . The apparatus for measuring a load of a construction machine according to  claim 3 ,
 wherein the construction machine is a dump truck for transporting the load on the dump body from one place to another.   
     
     
         9 . The apparatus for measuring a load of a construction machine according to  claim 4 ,
 wherein the construction machine is a dump truck for transporting the load on the dump body from one place to another.   
     
     
         10 . The apparatus for measuring a load of a construction machine according to  claim 5 ,
 wherein the construction machine is a dump truck for transporting the load on the dump body from one place to another.