JPS6231286B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a load cell for a vehicle that detects, displays, indicates, and/or records the weight of a load on a vehicle.

Conventional vehicle load meters detect the amount of load using magnetostrictive elements or strain gauges attached to the front and rear axles of the vehicle, subtract the vehicle's unloaded weight from this amount to determine the amount of live load, and then issue instructions. It is common to do so.

These load cells are affected by vibrations that occur when loading or unloading cargo while the vehicle is stationary, or by acceleration, deceleration, or vibrations that occur when the vehicle is accelerating, braking, or bouncing, and cannot accurately measure the amount of load. I may not be able to give instructions. Although this phenomenon is temporary, it occurs frequently, especially while driving, and in some cases, the indicator may go out of control, or when recording with a recorder, the recorded information may be extremely difficult to read. A problem had arisen.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a load meter in which the indications and records of the load indicator and recorder do not fluctuate due to the vibrations applied to the vehicle.

Another object of the present invention is to provide a load meter that indicates and records the amount of load when the vehicle is stopped and stationary while the vehicle is running.

The object of the present invention is to provide a load meter that records the detected load amount in several stages over time.

Another object of the present invention is to provide a load cell that issues an alarm when there is a load greater than a predetermined amount that causes the load capacity to exceed the rating.

A further object of the present invention is to provide a load cell to which a display such as a lamp array can be connected to provide a guide when loading a load.

The present invention uses an acceleration sensor to
When the detected load amount changes due to acceleration (or deceleration) of the vehicle, the previous detected load is given to the display means, and after the acceleration is no longer applied, the load amount in the stable state after the change is displayed. The purpose of this is a load cell that detects and displays.

Finally, the present invention uses a slope sensor to detect whether or not the vehicle is tilted, since the detected load value fluctuates while the vehicle is stopped at a traffic light at a sloped intersection. When the tilt detection signal disappears, the supply of the detected load value to the display means is stopped using that detection signal, the previous detected load value is supplied, and after the inclination detection signal disappears, the current detected load value is given to the display means. It is intended for a load cell with a

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below as illustrated in the accompanying drawings.

FIG. 1 is a block diagram showing the structure of a load cell according to the present invention. The structure indicated by reference numeral A in FIG. 1 shows a conventional load cell. This conventional load cell A has a load detection sensor 1 which is usually attached to the front and rear axles of the vehicle body and preferably is a magnetic deflection sensor.
a and 1b. Depending on the structure of the vehicle body or the required accuracy of the load meter, more sensors may be installed. The outputs of the load detection sensors 1a, 1b are guided to gain adjustment circuits 2a, 2b. As mentioned above, the load detection sensors 1a and 1b are usually attached to the front and rear axles of the vehicle body, and therefore, even when the vehicle is not loaded, these sensors receive stress or strain from the vehicle body, and their respective output characteristics differ.
Therefore, when the vehicle is not loaded, this gain adjustment circuit 2
The amplification degrees of a and 2b are adjusted so that the output characteristics from both sensors match, and the zero point of both output characteristics is determined. The outputs of the gain adjustment circuits 2a and 2b are connected to an adder circuit 3. The adder circuit 3 is constituted by, for example, an ordinary analog adder, and adds the detected load signals from each gain adjustment circuit 2a, 2b to obtain the sum of the load on the front axle side and the load on the rear axle side. The output of the adder circuit 3 is connected to a differential amplifier circuit 5 via an AC-DC converter circuit 4 composed of, for example, a rectifier circuit and an integrating circuit. The differential amplifier circuit 5 is composed of, for example, a differential amplifier, and a DC detection load signal rectified by the AC-DC converter circuit 4 is applied to one input, and the dead weight of the vehicle (no load) is applied to the other input. A signal corresponding to the state) is applied, and the net load amount obtained by subtracting the self-weight from the detected load is output. That is, the output signal is zero when no cargo is loaded, and when a load is loaded, the DC detected load signal is amplified and output. The output of the differential amplifier circuit 5 is connected to the load indicator 7 via a buffer circuit 6 with a gain of 1 and a switch 8 which is controlled by a latch signal to be described later and is newly provided according to the present invention. This load indicator 7 is
In the present invention, so-called crossed coil type instruments are particularly suitable. This type of instrument does not use a full swing for returning the pointer to zero and balancing the indication, but is of the type that is braked with silicone oil, etc., so after the pointer swings to a certain value, it is necessary to input the drive. If the instruction is rejected, the instruction is held, and when input is received again, the instruction is given in accordance with the amount of input at that time. Note that the indicator 7 can be used with any other instrument than the above-mentioned crossed coil type instrument, as long as the indicator 7 retains the indication when the input is cut off, and when the input is input again, it gives an indication appropriate to the input amount at that time. Applicable.

The output of the buffer circuit 6 is further connected to, for example, three comparators 9a, 9b, 9c. Each comparator is for comparing how much load there is with respect to the maximum live load, comparator 9a is for example 20% of the maximum live load, comparator 9b is for example 80%,
Comparator 9c is then set to detect 120%. The reason why there are three comparators is because the recorder, which will be described later, uses a four-stage recording method of 0-20%, 20-80%, 80-120%, and 120% or more. This is to determine the threshold value.

The output of each comparator is transferred to a shift register 10.
connected to a, 10b, and 10c. For example, each shift register has 4 digits, and the clock pulse cp
The output state of the comparator is sequentially read and carried every cycle, and the instantaneous fluctuation of the detected load is stored.

The output of each shift register is connected to a gate circuit 11, and instantaneous fluctuations in the detected load are monitored.

The outputs of comparators 9a, 9b and 9c are also input to latch circuit 12, respectively. When the latch circuit 12 receives a latch input from the gate circuit 11, its output maintains the value of the input before the latch input even if the input from the comparator changes.

The output of the latch circuit 12 is connected to the load recorder 13, and the outputs of the comparators 9a, 9b, 9c are combined and recorded in four stages as described above.

A speed sensor 14 is also connected to the gate circuit 11 and operates the gate circuit 11 to latch the latch circuit 12 while the vehicle is running.

Note that this speed sensor 14 can also be an acceleration sensor that detects acceleration (acceleration, deceleration, braking, turning, bouncing, etc.).

The gate circuit 11 further includes a slope sensor 1.
6 is connected, and when the vehicle body is tilted, the gate circuit 11 is configured to latch the latch circuit 12.
make it work.

The output of the gate circuit 11 is further connected to a switch control circuit 15, and similarly to the operation of the latch circuit 12, the output of the gate circuit 11 operates to open the switch 8.

Next, the operation will be explained with reference to FIG. 2, which shows the load cell according to the present invention in more detail.

As mentioned above, the detected load signal appears in analog form at the output of the buffer circuit 6, and the load indicator 7
and the non-inverting inputs of three comparators 9a, 9b, 9c. The voltage of the stabilized power supply Vcc is divided into voltages corresponding to 20%, 80%, and 120% of the maximum load, respectively, to the inverting input of each comparator. Therefore, the comparator 9a is set to 0 of the maximum load.
It outputs L level (0) at ~20%, and outputs H level (1) when it exceeds 20%. Similarly, the comparator 9b outputs L level when 0 to 80%, and H level when it exceeds 80%, and comparator 9c outputs L level when 0 to 120%, and outputs H level when 120% is exceeded.
%, outputs H level.

The output state of each comparator is sequentially read into shift registers 10a, 10b, and 10c by clock pulse CP, and carried up sequentially. The output of each digit of the shift register is provided with three exclusive OR gates 20 and one NOR gate 21a, respectively, to detect whether the contents of all digits are the same value.
21b or 21c is further connected to an AND gate 22 which receives the output of each NOR gate.

This will be explained using a numerical example. Let us now assume that the vehicle is loaded with cargo that corresponds to 70% of the maximum carrying capacity. Since the detected load signal is input to the comparator as a signal equivalent to 70%, the comparators 9a, 9b, and 9c output levels H, L, and L, respectively. Therefore, all 1's are input to the shift register 10a, and all 0's are input to the shift registers 10b and 10c. Therefore, exclusive OR gate 20 and
NOR gate 21 detects a match and becomes level “1”
Output. If the load detection sensors 1a and 1b detect a load corresponding to 100% in an instant when loading cargo into a vehicle (see Fig. 3), the load will be detected momentarily by the comparator 9b. , and the contents of the shift register 10b become "1, 0, 0, 0". Therefore, the contents of the shift register 10b no longer match, so the output of the NOR gate 21b outputs a level "0", and therefore the ANO gate 23 also outputs a level "0", and the latch circuit 12 outputs the previous signal value. is retained and output. This state is shift register 1
This continues until the "1" in the first digit of 0b is carried up by the clock pulse cp and disappears.

If the contents of the shift registers are all the same (1 or 0), all three inputs of the AND gate 22 will be "1", so its output will be "1". Therefore, "1" is applied to the enable terminal E of the latch circuit 12 via the AND gate 23.
is input, the latch is released, and latch circuit 1
2 passes the signals from the comparators 9a, 9b, and 9c to the load recorder 13.

At the same time, the output of AND gate 23 is given to switch control circuit 15. Switch control circuit 15
Similarly to the latch circuit 12, the switch 8 is operated to open the switch 8 upon input of level "0", thereby preventing the load indicator 7 from operating in response to a transient detected load signal.

A second input of the AND gate 23 is connected to the speed sensor 14 . The speed sensor 14 outputs a signal of level "1" while the vehicle is stopped, and outputs a signal of level "0" while the vehicle is running. Therefore, while the vehicle is running, the AND gate 23 outputs level "0" regardless of the output state of the AND gate 22, operates the switch 8 and latch circuit 12, and controls the load indicator 7 and recorder 13. override and indicate and record the amount of load prior to operation of the latch circuit 12.

As mentioned above, the speed sensor 14 can also be an acceleration sensor. In this case as well, a signal of level "1" is output while no acceleration is being detected, and a signal of level "0" is output while detecting acceleration.

A third input of the AND gate 23 is connected to the slope sensor 16 . The slope sensor 16 outputs a level "1" signal when the vehicle is not tilted, and outputs a level "0" signal when the vehicle is tilted.

Therefore, the AND gate 23 outputs a level "0" signal so as not to instruct or record real time when the vehicle is running or is accelerating, or is stopped on a slope. .

Next, the load recorder 13 will be explained. Three signal lines are connected to the input of the load recorder 13, and by the combination of these signals and the clock pulse,
Four stages of recording are performed. Figure 4 shows, for example, 1
An example of a waveform recorded on a circular chart paper that rotates once per day is shown. According to Figure 4, the baseline is drawn for loads between 0 and 20%, and the level a is drawn between 20 and 80%, and the level is 80.
A recording method is used in which the level is drawn at ~120% b, and at 120% or higher, the recording pen is moved back and forth between the base line and level b to fill in the area.
Note that since recorders having such a recording method are well known, details will be omitted.

Also, 120% of the three outputs of the latch circuit 12
An alarm device 24 is connected to the output associated with load detection. Therefore, if the load exceeds 120%, a warning is emitted by a lamp or the like, so that the driver can be informed of the overload before starting the vehicle.

Furthermore, although not shown in the figure, the output of the latch circuit 12 is taken out to the outside and connected to, for example, three lamps, so that when the load is 0 to 20%, none of the lamps lights up, and when the load is 20 to 80%, the first lamp is turned on. The first and second lamps may be lit at 80-120%, and all lamps may be lit at 120% or higher to notify the cargo loader.

As described above, according to the present invention, when there is a large variation in the detected load amount in a vehicle load meter,
This fluctuation is detected, the input to the load indicator is interrupted during that time, and the load amount before cutting is maintained, so transient fluctuations in the detected load signal can be suppressed. Even when recording the amount, the input signal is cut off when there is a change, and the recorded amount before the cutoff is maintained, so the recording paper can be made very easy to read.

Further, in the present invention, while the vehicle is running, the load amount when the vehicle is stopped is instructed and recorded, so that fluctuations in the load amount that frequently occur due to starting, braking, etc. can be eliminated. Alternatively, since the load amount in a stable state before an unstable state such as acceleration, deceleration, turning, or bouncing occurs is instructed and recorded, fluctuations in the load amount that occur during the above-mentioned unstable state can be eliminated.

Further, according to the present invention, even when the vehicle is tilted, the load amount before the tilt is indicated and recorded, so that errors in detecting the load amount caused by the tilt can be eliminated.

Although the load cell according to the present invention has been described as including a load indicator and a load recorder that have the function of indicating and recording the load amount, it is also possible to use only an indicator like a conventional load cell. Of course, a recorder alone is sufficient.

Although the present invention has been described in detail with reference to a preferred embodiment thereof, the present invention is not limited to this particular embodiment, and can be modified in many ways without departing from the spirit of the invention. For example, in the preferred embodiment of the present invention, a load cell that displays the net load after subtracting the vehicle's own weight has been described, but it can also be applied to a load cell that displays the total vehicle weight including the live load. It is something.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a preferred embodiment of the vehicle load cell according to the present invention, FIG. 2 is a partially detailed view of the vehicle load cell according to the present invention, and FIG. 3 is a block diagram showing a preferred embodiment of the vehicle load cell according to the present invention. FIG. 4 is a diagram showing signals appearing in each part, and FIG. 4 is a diagram showing an example of recording on recording paper. 1a, 1b...Load detection sensor, 2a, 2b...
... Gain adjustment circuit, 3 ... Adder, 4 ... AC-DC conversion circuit, 5 ... Differential amplifier circuit, 6 ... Buffer circuit, 7 ... Load indicator, 8 ... Switch, 9
a, 9b, 9c... Comparator, 10a, 10b, 1
0c...Shift register, a, 11...Gate circuit, 12...Latch circuit, 13...Load recorder,
14...Speed sensor, 15...Switch control circuit, 16...Slope sensor, 20...Exclusive
OR gate, 21a, 21b, 21c...NOR gate, 22, 23...AND gate.

Claims (1)

[Claims] 1. Means 9, 10, 11 for detecting rapid fluctuations in detected load values in a vehicle load meter including a load detection sensor and a control circuit for processing a detected load signal of the load detection sensor. , means for holding the detected load value before fluctuation, and means for displaying the load amount (7
and/or 13), wherein while the detection means is detecting a fluctuation, the holding means gives the detected load value before the fluctuation to the display means. 2. The vehicle load cell according to claim 1, wherein the display means is an indicator such as a crossed coil type having the function of the holding means. 3. The vehicle load meter according to claim 1, wherein the display means is a recorder. 4. The vehicle load according to claim 1, 2, or 3, wherein the detection means includes a speed sensor 14 to display the load amount when the vehicle is stopped while the vehicle is running. Total. 5. The vehicle load meter according to claim 3 or 4, wherein the recorder records the detected load amount in several stages over time. 6. Any one of claims 1 to 5, characterized in that an alarm device is connected to the detection means, and an alarm is issued when the detection means detects the detected load value equal to or higher than a predetermined value. The vehicle load cell described in item 1. 7. The vehicle load meter according to claim 5, characterized in that a display device is connected to the recorder and displayed in stages corresponding to the detected load amount divided into several stages. . 8. A patent claim characterized in that the detection means includes an acceleration sensor, and while the acceleration sensor is detecting acceleration, the holding means provides the display means with the detected load value before the detected load value changes. The vehicle load cell according to the first, second, or third range. 9 The detection means includes a slope sensor,
Claims 1 and 2 are characterized in that, while the slope sensor is detecting the vehicle inclination, the holding means provides the display means with the detected load value before the detected load value changes. Or the vehicle load cell described in paragraph 3.