JP2001208634A - Device and method for load measuring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a load measuring device with a remarkably reduced production cost as well as a small size and a good portability. SOLUTION: The load measuring device comprises a pressure sensor 203 for detecting a fluid pressure, a CPU 271 for calculating a load corresponding to the fluid pressure detected by the pressure sensor 203 based upon a specific initial input condition inputted at an initial setting and display means (CPU 271, a display part 50) for displaying the calculated load.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load measuring device and a load measuring method.

[0002]

2. Description of the Related Art A pressure gauge for detecting and displaying the pressure of a pressurized fluid such as working compressed air has been known. Japanese Patent Application Laid-Open No. H10-3838 by the present applicant discloses a pressure gauge having a processed side wall and a pressure sensor inserted into the pressure detection hole in order to reduce the size of the pressure gauge. A display unit for displaying the fluid pressure detected by the pressure sensor, a control circuit for the pressure sensor and the display unit,
A pressure gauge provided so as to surround the pipe or along the shape of the pipe, the pressure sensor and the control circuit being disposed therein, and a casing having the display unit disposed on the surface thereof. Has been disclosed. In this pressure gauge, the pressure gauge is provided so as to surround the pipe through which the fluid passes, so the size of the housing can be reduced to the size of a slightly larger joint, and the built-in power supply makes it easy to carry. It is characterized by doing.

On the other hand, most load measuring devices such as digital load cells use springs or strain gauges.

[0004]

A conventional load measuring device mainly uses a spring or a strain gauge, and a small-sized pressure gauge as disclosed in Japanese Patent Application Laid-Open No. 10-38738 is used. It has not been considered before that it is applied.

The present invention has been made in view of such a problem, and an object of the present invention is to reduce the manufacturing cost significantly by changing only the software using the configuration of the pressure gauge as it is. An object of the present invention is to provide a load measuring device and a load measuring method which are small and excellent in portability.

[0006]

According to a first aspect of the present invention, there is provided a load measuring device, comprising: a pressure sensor for detecting a pressure of a fluid; and a predetermined initial value inputted in an initial setting. The information processing apparatus includes a calculating unit that calculates a load corresponding to the fluid pressure detected by the pressure sensor based on an input condition, and a display unit that displays the load calculated by the calculating unit.

According to a second aspect of the present invention, in the load measuring device according to the first aspect, the initial setting is performed.
A method of calculating the load coefficient by inputting the weight of the reference weight while the reference weight is loaded on the luggage carrier, and calculating the load by inputting at least the cylinder diameter of the lift drive of the luggage carrier. Either of the methods can be selected.

According to a third aspect of the present invention, in the load measuring device according to the first aspect, the initial input condition input in the initial setting is stored, so that the zero adjustment is performed only by turning on and off a predetermined switch. To do.

According to a fourth aspect of the present invention, in the load measuring device according to the second aspect of the present invention, there is provided a measuring switch for instructing start and end of the measurement, and a clear switch, wherein the measuring switch is turned on and off. The clear switch is also used for inputting initial conditions, zero adjustment, displaying stored loads, and inverting display. The clear switch is also used for inputting initial conditions, storing loads, and displaying the total load.

According to a fifth aspect of the present invention, in the load measuring device according to the first aspect of the present invention, the load measuring device further includes a storage unit for storing the load calculated by the calculation unit, and temporarily stores the measured load in the storage unit. After the storage, the load is not stored unless the load is lowered and the load display is set to zero.

A sixth aspect of the present invention is a load measuring method, wherein the pressure of the fluid is detected by a pressure sensor, and the pressure corresponding to the detected fluid pressure is determined based on a predetermined initial input condition input in the initial setting. Then, the load is calculated by the calculation means, and the calculated load is displayed by the display means.

A seventh aspect of the present invention is the load measuring method according to the sixth aspect, wherein the initial setting is performed.
A method of calculating the load coefficient by inputting the weight of the reference weight while the reference weight is loaded on the luggage carrier, and calculating the load by inputting at least the cylinder diameter of the lift drive of the luggage carrier. Either of the methods can be selected.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the present embodiment, it is assumed that the load measuring device (digital load cell) of the present invention is used by being attached to a predetermined location of a load carrying device, for example, a forklift.

FIG. 1 is a diagram showing an overview of a digital load cell according to an embodiment of the present invention. The display unit 50 indicates that the load is 3
LCD display 10 capable of displaying digits, a load coefficient calculation method display 11A indicating that the load coefficient calculation method has been selected, and a cylinder diameter input method display 11B indicating that the cylinder diameter input method has been selected. The display section 11C of the measurement method, the display (+ M) 12A for indicating that the load display on the LCD display 10 is the currently stored additive load, and the load display on the LCD display 10 are cumulative. A display (C) 12B for indicating that the load is applied, and a display section 12C for memory contents. L
The CD display 10 has indications 10A and 10B indicating decimal points, and specifically, for example, 2.00 tons (TON).
Is displayed. The operation unit includes a measurement switch 51 for starting and ending the measurement and a clear switch 52. The measurement switch 51 is also used for power ON / OFF, input of initial conditions, zero adjustment, display of stored load, and reverse display, and the clear switch 52 is used for input of initial conditions, storage of load, and total load. Also used for display.

In the digital load cell of this embodiment, the load display on the LCD display 10 when the load is measured is 5
Updated four times at second intervals, and the average load after 20 seconds is fixedly displayed as a normal load. After this display is continued for 10 minutes, the display is automatically turned off. When a load variation of 50 kg or more is applied, the load is updated four times at 5-second intervals, and the average load after 20 seconds is fixedly displayed as a normal load.

If the load is less than 0.03 ton as the minimum measurement range, 0 is displayed. The load display resolution is 10 kg.
In addition, since the cylinder diameter, quantity, and arrangement of the load measurement range differ depending on the mast of the forklift,
The stroke range of the FR cylinder (front cylinder) is the first stage based on the mast type.

In this embodiment, a memory for storing the measured load is provided, but the load at the time of measurement is added to the currently stored load every time the load is measured. The load stored in the memory is read out by pressing the measurement switch 51 and displayed on the LCD display 10 (+ M).
It is displayed together with 12A. After the measurement result of the load is displayed on the LCD display 10, if the load whose measurement has been completed is lowered, 0 is displayed. When the clear switch 52 is pressed at this point, the total load so far is displayed (表示) 12B.
Is displayed on the LCD display 10.

Further, it is possible to display the load display range up to 9.00 tons (rounding is performed for 10 kg or less). When the total memory exceeds 9 tons, the display (+ M) 12A flashes and the memory function is stopped. However, the measured load before blinking is displayed, but if the display of the total load is instructed, 9 tons blink.

In this embodiment, a coin-type lithium battery (3 V, 220 mAh) is used as a power supply. The life varies depending on the use conditions (environment).
1 year (25 minutes)
0 days / year) is possible. When the power supply becomes 2.7 V or less, "LLL" is displayed blinking (at 0.5 second intervals) and the display is maintained until the power supply is turned off. Pressing the measurement start button again starts the measurement of the battery voltage.

FIG. 2 is a functional block diagram of the digital load cell according to the present embodiment. Pressure sensor 20 for detecting pressure
3 is connected to a power supply 201 via a gain setting circuit 210 on the input side. The output side of the pressure sensor 203 is connected to the CPU 271 via the amplifier 205. The CPU 271 further includes an operation unit 5 having the measurement switch 51 and the clear switch 52 described above.
3 and the display unit 50 described above are connected. Also,
The CPU 271 includes an A / D converter for converting an input signal into a digital signal, a calculation program for calculating a load, and a memory for storing the measured load as an added load or a cumulative load. .

After the pressure detected by the pressure sensor 203 is converted into an electric signal, the pressure is input to the amplifier 205, amplified, and input to the CPU 271. The CPU 271 starts an operation program stored in the memory, performs an operation of converting pressure into a load, and displays the load on the LCD display 10 as a measured value. When the output signal of the pressure sensor 203 exceeds the threshold value, the control signal S output from the CPU 271 is supplied to the gain setting circuit 210 to adjust the gain.

FIG. 3 is a flow chart for explaining the initial setting procedure prior to the load measurement. In this embodiment, in this initial setting, the reference weight (here, 50 to 9) is used.
000kg range) on a forklift and calculate the load coefficient, or input the cylinder diameter and the number of cylinders of the forklift and multiply them by pressure to calculate the load. It has become.

First, when the measurement switch 51 is pressed for 3 seconds or more (step S1), it is determined whether or not the initialization has been completed (step S2). Measurement reading control to read load and control display, LCD
The control function for controlling the lighting time and further monitoring the battery life is activated. If the initial setting has already been completed, the measurement can be immediately performed (Step S).
19). The initial setting is performed when the device is purchased or when the battery is replaced. Even if the measurement switch 51 is pressed without performing the initial setting, the user is informed that the measurement cannot be performed by the display as shown in FIG. To be notified.

After the control function is activated, when the measurement switch 51 and the clear switch 52 are simultaneously pressed for three seconds or more (step S4), the load coefficient calculation display 11A blinks as shown in FIG. 5A. Display. Here, when the reference weight is placed, the load coefficient calculation method is automatically set to start to be selected (step S5). Next, it is determined whether the measurement switch 51 has been pressed (step S6).
In the case of ES, a state is prepared for starting the selection of the cylinder diameter and the number of cylinder input methods, and a display for blinking the cylinder diameter input display 11B is performed as shown in FIG. 5B (step S7).

Next, it is confirmed whether or not the measurement switch 51 has been pressed again (step S8). If YES, the process returns to step S5 to be in a preparation state for starting the selection of the load coefficient calculation method. When the measurement switch 51 is further pressed, the process proceeds to step S7, and the state is again prepared for starting the selection of the cylinder diameter input method.

On the other hand, step S6 or step S8
When the clear switch 52 is depressed without pressing the measurement switch (Step S9), the selection completion processing of the currently selected measurement method is performed (Step S1).
0). Here, as shown in FIG. 5 (C) or FIG. 5 (D), a selection completion display for blinking “0” in the first digit is performed. FIG. 5C shows the completion of the load coefficient calculation method.
FIG. 5D shows a completion display of the cylinder diameter input method. In this state, even if a load is applied to the cylinder, the display is in the zero adjustment state and the display does not change. Next, initial conditions are input using the measurement switch 51 and the clear switch 52 (step S11).

First, the case where the load coefficient calculation method is selected will be described. If a tare (pallet, container, etc.) is to be included in the measurement, the reference weight is placed on the fork, the fork is raised, and a load is applied to the cylinder, and the weight of the reference weight is input in kg. Until this input is made, the display of FIG. 5C in which the first digit “0” blinks is still continued.

If the tare is not included in the measurement, the tare and the reference weight are placed on the fork, the fork is raised, and the weight of the reference weight is input in kg.

Each time the measurement switch 51 is pressed, the input method changes while the numbers 0 to 9 blink in the first digit, and when the clear switch 52 is pressed, the first digit is determined and the second digit is determined. 0 is displayed blinking. When the same operation is performed up to the third digit in kg units and the clear switch 52 is pressed (step S12), the load coefficient is calculated and stored (step S13), and as shown in FIG.
A display for blinking "0" of the third digit is performed (step S14).

If the measurement switch 51 is pressed (step S15), the flow advances to step S16 to reverse the display direction. If the measurement switch 51 is further pressed (step S17), the display direction is rotated forward and step S1 is performed.
Returning to step 4, blinking display is performed.

If the clear switch 52 is depressed without pressing the measurement switch 51 in step S15 or step S17 (step S18), the initial setting is completed and the measurement becomes possible (step S19). In this case, the display of FIG. 5F (forward display) or FIG. 5G (reverse display) is maintained.

Next, proceeding to step S20, zero adjustment is performed by storing the initial input conditions (input of the weight of the reference weight) by turning the measurement switch 51 on and off.
Here, it goes without saying that a tare is included. However, since a loss load other than the tare is generated due to frictional resistance of a piston seal of a chain or a cylinder used in a forklift, it is desirable to perform zero adjustment.

Next, the case where the cylinder diameter input method is selected will be described. Tare for measurement (pallets, containers, etc.)
Is included, the fork is raised, the cylinder is loaded, and the cylinder diameter is entered in millimeters. Until this input is made, the display of FIG. 5D in which the first digit “0” blinks is still continued.

If the measurement does not include the tare, the tare is placed on the fork, the fork is raised, the cylinder is loaded, and the cylinder diameter is entered in millimeters.

In the input method, each time the measurement switch 51 is pressed, the number changes from the first digit, and when the clear switch 52 is pressed, the number is determined and the second digit 0 blinks. In the same manner, when the cylinder diameter is input to the third digit in millimeter units and the clear switch 52 is pressed (step S12), the cylinder diameter is stored (step S13) and the input of the number of cylinders is started, and at the same time, FIG. As shown in A), a display for blinking the first digit "0" is performed (step S14).

When a FR cylinder (front cylinder) is driven via a chain, a two-digit number is used. In this case, 0.5 is used when one cylinder is used, and 1.0 is used when two cylinders are used. Input by the operation of 51. Also, FR
When the cylinder is driven directly, a two-digit number is input. In this case, 1.0 is used for using one cylinder, and 2.0 is input for two cylinders by operating the measurement switch 12. When the clear switch 52 is pressed, FIG. As shown in B), a display for blinking "0" in the first to third digits is performed.

Here, by pressing the measurement switch 51, the display direction can be reversed in the same manner as the method of calculating the load coefficient by placing the reference weight.

If the clear switch 52 is pressed (step S18) without pressing the measurement switch 51 in step S15 or step S17, the initial setting is completed and the measurement is enabled (step S19). In this case, the display of FIG. 6C (forward display) or FIG. 6D (reverse display) is maintained. The next zero adjustment step (step S20) is the same as the method of calculating the load coefficient by placing the reference weight.

Note that the initial setting can be set to all clear by removing the battery while the power is off. Further, in the present embodiment, the above two methods cannot be simultaneously input.

Next, a procedure for actually performing the measurement after the completion of the initial setting will be described with reference to FIG. First, the power is turned on by pressing the measurement switch 51 for 3 seconds or more.
The ON operation is not performed in less than 3 seconds. In response to this operation, a display as shown in FIG. 7A (when the load coefficient is calculated with the reference weight placed) or FIG. 7B (when the cylinder diameter and the number of cylinders are input) is displayed. Then, it becomes a measurable state (step S19). Power ON
The display is displayed continuously for 10 minutes from the start, and when the time exceeds 10 minutes, the power is automatically turned off with the initial settings stored. This is called Auto Power off.

Note that if the display of FIG. 7C is held when the power is turned on, it means that the initial setting has not been made, so that it is necessary to perform the initial setting by the above method.

Next, a measurement is performed with a heavy object placed (step S30). The measurement here is performed based on a load coefficient calculated by placing a reference weight on the initial setting or a load calculated by inputting the cylinder diameter and the number of cylinders and multiplying the input values. After loading a heavy object, measure every 5 seconds (re-measure if the load fluctuates more than 50kg),
The average load per second is rounded to 10 kg or less and displayed up to 9 tons. When it becomes 9 tons or more, the user is warned by blinking display.

Next, the measured load is displayed (step S31). When the clear switch 52 is pressed while the load is displayed (Step S32), the load value currently displayed is stored in the memory (Step S33), and the load display of Step S31 is held as it is (Step S33 '). If the previous load value has already been stored in the memory, the current load value is added to the previous load value. However, the input of the display load to the memory is effective only once, and the memory is not stored unless the heavy load is once lowered and the display load is set to 0.

Here, when the measurement switch 51 is pressed (step S34), the display "+ M" is displayed and held, and at the same time, the added load is read from the memory and displayed and held (step S3).
5). The display at this time is as shown in FIG. 7 (D) or FIG. 7 (E). However, even if a load is applied while the stored load is being displayed, the load is not displayed. Here, when the clear switch 52 is pressed (step S36), a step S3 is performed.
It returns to the load display of 3 '. Since the display at this time is not the load of the memory but the load of the currently loaded heavy object, the display (+ M) 12A is turned off.

When the heavy object is lowered in a state where the load of the loaded heavy object is displayed (step S33 ') (step S33).
37), the load display is set to 0 (step S38).
FIGS. 7F and 7G show an example of the 0 display.

If the clear switch 52 is not pressed while the load display is "0" (step S39), and the next heavy object is placed, the process returns to step S30 and the measurement is performed in the same procedure as described above. When the clear switch 52 is pressed in the state where the load display is 0, it is determined that the measurement is completed, and as shown in FIG. 7 (H) or FIG.
The total load is displayed together with 2B (step S4).
0). FIG. 7 (H) or FIG. 7 (I) shows a case where the total load is 2 tons.

When the clear switch 52 is pressed with the accumulated load displayed (step S41), the display of Σ and the load are turned off, and the load stored in the memory is also cleared to return to the first measurement start state. When the measurement switch 51 is pressed for three seconds or more, the display is turned off with the initial settings stored (step S42). It does not turn off in less than 3 seconds. Step S40
After 10 minutes, if no operation is performed, the display is automatically turned off (step S43).

When the battery is low, a low voltage mark as shown in FIG. 7 (J) is displayed blinking to prompt the user to replace the battery. Conversely, if it is desired to clear the initial settings, the battery may be removed while the power is off.
When the battery is replaced, the memory of the initial setting is erased. However, it is also possible to use a capacitor or the like so that the memory of the initial setting is retained even if the battery is removed.

According to the above-described embodiment, the digital load cell is configured by using only the configuration of the pressure gauge and changing only the software. Therefore, the manufacturing cost is greatly reduced, and the compact and excellent portability is achieved. Load measuring device can be realized. Furthermore, according to the present embodiment, forklifts, trucks, etc., check the loading weight and prevent accidents due to overloading of heavy objects, hydraulic / pneumatic hoists, prevent accidents by checking the load of cranes, etc. The effect of improvement of the effect is obtained.

[0050]

According to the present invention, it is possible to provide a load measuring apparatus and a load measuring method which are small and excellent in portability while significantly reducing the manufacturing cost.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overview of a digital load cell according to an embodiment of the present invention.

FIG. 2 is a functional block diagram of the digital load cell according to the embodiment.

FIG. 3 is a flowchart illustrating a procedure of an initial setting prior to a load measurement.

FIG. 4 is a flowchart for explaining a procedure for actually performing measurement after completion of initialization.

FIG. 5 is a diagram showing display contents at the time of initial setting when a measurement method is selected and when a method of calculating a load coefficient by placing a reference weight is selected.

FIG. 6 is a diagram showing display contents at the time of initial setting when an input method of a cylinder diameter and the number of cylinders is selected.

FIG. 7 is a diagram showing display contents at the time of measurement.

[Explanation of symbols]

10 LCD display 10A, 10B Display indicating decimal point 11A Display of load coefficient calculation method 11B Display of cylinder diameter input method 12A Display for indicating that it is the current added load 12B Display for indicating the total load 50 Display unit 51 Measurement switch 52 Clear switch 53 Operation unit 201 Power supply 210 Gain setting circuit 203 Pressure sensor 205 Amplifier 271 CPU

Claims (7)

[Claims] 1. A pressure sensor for detecting a pressure of a fluid, and a calculating means for calculating a load corresponding to the fluid pressure detected by the pressure sensor based on a predetermined initial input condition input in an initial setting. And a display unit for displaying the load calculated by the calculation unit. 2. A method for calculating a load coefficient by inputting a weight of the reference weight while the reference weight is loaded on the luggage carrier when performing the initial setting, and at least a lift of the luggage carrier. 2. The load measuring device according to claim 1, wherein any one of a method of calculating a load by inputting a driving cylinder diameter can be selected. 3. By storing an initial input condition input in the initial setting, a predetermined switch ON,
2. The load measuring device according to claim 1, wherein the zero adjustment is performed only by an OFF operation. 4. A measurement switch for instructing start and end of measurement, and a clear switch, wherein the measurement switch is for turning on / off a power supply, inputting initial conditions, zero adjustment,
3. The clear switch according to claim 2, wherein the clear switch is also used for inputting initial conditions, storing a load, and displaying a total load.
The load measuring device as described. 5. A storage means for storing the load calculated by said calculation means, and once the measured load is stored in said storage means, unless the load is lowered and the load display becomes zero. 2. The load measuring device according to claim 1, wherein the load is not stored. 6. A fluid pressure is detected by a pressure sensor, and a load is calculated by a calculating means in accordance with the detected fluid pressure based on a predetermined initial input condition input in the initial setting. A load measuring method, wherein the load is displayed by a display means. 7. A method of calculating a load coefficient by inputting the weight of the reference weight while the reference weight is loaded on the luggage carrier when performing the initial setting, and at least a lift of the luggage carrier. 7. The load measuring method according to claim 6, wherein one of a method of calculating a load by inputting a driving cylinder diameter can be selected.