JPS6224359B2 - - Google Patents

Description

[Detailed description of the invention] The present invention is provided in a working machine such as a crane,
The present invention relates to a moment limiter used to safely operate the moment limiter, and particularly to a moment limiter inspection device suitable for inspecting the moment limiter.

In a working machine, such as a crane, the moment acting on the boom is determined by the length of the boom (including the jib length; the same applies hereinafter), the angle of the boom during work, and the actual load suspended by the boom. If a certain limit is exceeded, accidents such as the crane falling may occur. Moment limiters are used to prevent such accidents.

First, we will explain the moment limiter. FIG. 1 shows the schematic configuration of a crane as an example of a working machine. In the figure, 1 is the crane body, 2 is the boom, 3 is the suspended load, 4 is the rope for hoisting the suspended load, 5 is the rope for hoisting the boom 2, and 6 is the actual load of the suspended load 3 due to the tension of the rope 4. The load detection device 7 is an angle detection device that detects the elevation angle of the boom 2. 8 is a device including a calculation device, a display device, etc. (hereinafter referred to as the calculation device);
installed in the driver's seat. The load detection device 6, the angle detection device 7, and the calculation device 8 constitute a moment limiter.

FIG. 2 is a block diagram showing an example of a moment limiter that is being considered based on recent developments in microcomputers.

A multiplexer 9 switches and inputs data from the load detection device 6 and the angle detection device 7. Reference numeral 10 denotes an A/D converter that converts analog quantity data from the load detection device 6 and the angle detection device 7 into corresponding digital quantities. In addition, the load detector 6 and the angle detector 7 are A/D by themselves.
Some devices have a converter, in which case the A/D converter 10 is not necessary. Reference numeral 11 denotes a microprocessor unit (hereinafter referred to as MPU), which is an arithmetic control section that performs various calculations and controls in accordance with a control program in ROM 12, which will be described later. CL is MPU1
This is a clock that regulates the operation of the clock 1, and generates clock pulses of a constant period.

12 is a read-only memory (hereinafter referred to as ROM) in which a control program for the MPU 11 is stored. The MPU 11 performs calculations, extracts necessary data, and performs various other controls in accordance with this control program. 13 is a random access memory (hereinafter referred to as RAM), which is a memory for temporarily storing various data and calculation results. 14 is a ROM in which the boom length and rated load value of the crane are stored. The boom length is the basis of calculation, and the boom length currently in use is selected by switch SW1. The rated load value is a value determined for each crane model according to the working radius of its boom. 17 is MPU11
This is an output circuit for outputting the calculation results to the display device 19, alarm device 20, and automatic stop output terminal 21.

The display device 19 is provided on the panel part of the crane main body 1, and has a configuration in which light emitting elements L ₁ to L ₁₁ such as lamps and light emitting diodes are arranged in a line as shown in FIG. The lights will turn on in sequence according to the ratio of the load to the rated load. For example, if the load factor is 0
When the load factor is ~9%, the light emitting element _L1 is at a load factor of 10~19%.
When , light emitting elements L ₁ and L ₂ emit light. Thereafter, light is emitted in the same manner, and when the load factor is 90 to 99%, the light emitting elements L ₁ to _{L 10} all emit light, and when the load factor is 100% or more, the light emitting elements L ₁ to L ₁₁ all emit light. Thereby, the load factor can be displayed in the form of a bar graph, and the load factor during work can be grasped intuitively at a glance.

The alarm device 20 is a device for notifying the crane operator of the dangerous state of the crane by sound,
For example, when the load factor reaches 90% and light emitting element L ₁₀ lights up, the buzzer generates an intermittent sound to warn of danger, and when the load factor reaches 100% or more and light emitting element L ₁₁ lights up, the buzzer emits a continuous sound. to warn of danger.

The automatic stop output terminal 21 generates an automatic stop output signal when the load factor is 100% or more and the light emitting element L ₁₁ lights up, and drives the stop device (not shown) connected to this signal to stop the boom 2. Further descent and hoisting of the hoisting rope 4 are stopped.

18 is a selection signal generation circuit, which selects the multiplexer 9 and A/D according to the control signal from the MPU 11.
Converter 10, ROM12, RAM13, ROM1
4. Generate a signal to select one of the output circuits 17, etc. and put it into operation.

MPU11, clock CL, ROM12, RAM1
3. The ROM 14 and the selection signal generation circuit 18 constitute a microcomputer. In the figure, A indicates an address bus, C indicates a control bus, and D indicates a data bus.

Next, the operation of this moment limiter will be explained with reference to the flowchart shown in FIG.

When the power is turned on, MPU11 operates and ROM1
Calculation and control are performed according to the program in step 2.
First, the angle signal θ from the angle detection device 7 is taken in via the multiplexer 9 and the A/D converter 10 (from the first step _S10 onwards, each step is _S1 , _S2 ...
Expressed as ), this is stored in the RAM 13. Next, the boom length data l currently in use is read from the ROM 14 (S ₂ ) and stored in the RAM 13. MPU
11 takes out the angle signal θ and boom length data l from the RAM 13 and calculates the working radius R (R=l cosθ)
(S ₃ ). The rated load value A corresponding to this working radius R is retrieved from the ROM 14 (S ₄ ), and this is
Store it in RAM13. Next, the multiplexer 9 is switched, the actual load W is input from the load detection device 6 via the A/D converter 10 (S ₅ ), and this is stored in the RAM.
13 to be memorized. Take out the rated load A and actual load W from RAM13 and load factor F (F=W×100/A
%) is calculated (S ₆ ). Next, this load factor F is 100
% or more (S ₇ ), and if it has not reached 100%, a signal to cause the corresponding light emitting element to emit light is output to the output circuit 17 (S ₈ ). In step _S7 , if it is determined that the load factor F is 100% or more, an automatic stop output signal is first output to the output circuit 17 ( _S9 ), and then a signal to cause all light emitting elements _L1 to _L11 to emit light and an alarm are output. Output a signal ( _S8 ). When the operations up to step _S8 are completed, the program is repeated again from the first step _S1 .

In this way, the load factor F is always displayed by the light emitting elements L ₁ to _{L 11} , so the operator can intuitively grasp the working status and take necessary safety measures immediately when a dangerous situation approaches. It is possible.

By the way, in conventional analog moment limiters that do not use such a microcomputer, a vertically long scale is provided as a display device, and a meter with a pointer that moves along this scale, or a meter with a pointer that moves along this scale, or a plurality of meters instead of this meter is used. An array of lamps was used. When inspecting these display devices, you can apply a voltage of any waveform directly to the meter to activate the pointer, or connect a power source directly to the lamp to light the lamp, and check whether the pointer moves or not. Or they just checked to see if there was a break in the lamp. Although such a test is sufficient to test the display device itself, it cannot be determined whether the display device operates correctly when the moment limiter is used.

Considering this point for the display device shown in FIG. 3, simply connecting a power source directly to each light emitting element L ₁ to _{L 11} will only allow you to see whether each light emitting element L ₁ to L ₁₁ emits light or not. , it is impossible to perform tests related to operation, such as whether or not each of the light emitting elements L ₁ to L ₁₁ can sequentially emit light. However, for such display devices, it is extremely important for the purpose of the moment limiter whether the light emission of each light emitting element increases and decreases in the correct order, and testing of the display device itself alone is not sufficient. That is not possible.

As described above, the more complex the display device is, the more strongly it is desired to inspect not only the display device itself but also whether or not it operates correctly.

SUMMARY OF THE INVENTION An object of the present invention is to provide a moment limiter testing device that eliminates the above-mentioned conventional drawbacks and is capable of testing the display device itself and whether or not the display device operates correctly.

In order to achieve this object, the present invention provides a moment limiter with a counter circuit that counts at arbitrary time intervals and a test switch, and only when the test switch is operated. The present invention is characterized in that the count number of the circuit is taken in, and corresponding ones of the plurality of display elements constituting the display device of the moment limiter are sequentially activated in accordance with the count number.

The present invention will be explained below based on the embodiment shown in FIG.

In the figure, the same parts as those shown in FIG. 2 are given the same reference numerals, and the explanation will be omitted. 8a is an arithmetic unit of this embodiment, and 12a is a ROM. The ROM 12a is the same as the ROM 12 shown in FIG. 2 in that it stores a control program for the moment limiter, but differs from the ROM 12 in that it also stores an inspection program in addition to this control program. 22 is the signal for inspection when inspecting moment limiter.
Buffer circuit outputting to MPU 11, 23
is a power supply connected to the buffer circuit 22 via a resistor 24, and SW2 is an inspection switch that is closed when inspecting the moment limiter. Inspection switch
When SW2 is open, that is, during normal control of the moment limiter, the buffer circuit 22 is supplied with a high potential from the power supply 23, so the buffer 22 outputs a corresponding signal. When the test switch SW2 closes, that is, when testing the moment limiter, the buffer circuit 22 closes the test switch SW2.
Since it is grounded through 2 and has a low potential, a signal different from the above signal is output accordingly. 25 is a counter circuit that divides and counts the frequency from the clock CL, and the counting interval can be set arbitrarily.

Next, the operation of the moment limiter shown in FIG. 5 will be explained with reference to the flowchart shown in FIG.

When you turn on the moment limiter,
The MPU 11 is brought to an initial state, and at the same time, the counter circuit 25 is reset to set its output number to "0" (S ₁₀ ). Next, the MPU 11 drives the selection signal generation circuit 18 to put the buffer circuit 22 into operation, inputs the signal, and turns on the test switch.
It is determined whether SW2 is closed or open ( _S11 ). If inspection switch SW2 is open,
In accordance with the normal moment limiter control operation program in the ROM 12a, each step _S1 to _S9 shown in FIG. 4 is performed, and the control operation program is repeated again from step _S11 .

In step _S11 , when it is determined that the inspection switch SW2 is closed, that is, the moment limiter is inspected, the control is from now on to the ROM 12.
It is moved to the inspection program of a. First, the MPU
11 takes in the numerical value of the counter circuit 25 and determines whether or not this numerical value is "0" (S ₁₂ ). if,
When determining that the numerical value is "0", the MPU 11 outputs a signal for extinguishing the light emitting elements _L1 to _L11 to the output circuit 17, thereby extinguishing all the light emitting elements ( _S13 ). Then, while the value of the counter circuit 25 is "0", the operations of step S ₁₁ , step S ₁₂ , and step S ₁₃ are sequentially repeated.

When the numerical value of the counter circuit 25 becomes "1" and it is determined in step _S12 that the numerical value is not "0", the MPU 11 determines whether the numerical value of the counter circuit 25 is "1" ( _S14 ). Since the value of the counter circuit 25 is "1", the MPU
11 outputs a signal that causes the light emitting element L ₁ to emit light to the output circuit 17, that is, the same signal as in the case of a load factor of 0 to 10% (one of them, for example, a 5% signal) to cause the light emitting element L ₁ to emit light. (S ₁₅ ). While the value of the counter circuit 25 is "1", the operations of step S ₁₁ , step S ₁₂ , step S ₁₄ and step S ₁₅ are sequentially repeated.

When the numerical value of the counter circuit 25 becomes "2" and it is determined in step _S14 that the numerical value is not "1", the MPU 11 determines whether the numerical value of the counter circuit 25 is "2" or not ( _S16 ). Since the numerical value is "2", MPU11 is output circuit 1.
7 to cause the light emitting elements L ₁ and L ₂ to emit light, i.e.,
The same signal as in the case of a load factor of 10 to 19% is output to cause the light emitting elements L ₁ and L ₂ to emit light (S ₁₇ ). Counter circuit 2
While the value of 5 is "2", step S ₁₁ , step
The operations of S ₁₂ , step S ₁₄ , step S ₁₆ , and step ₁₇ are repeated in sequence.

Thereafter, the same operation is repeated according to the count number of the counter circuit 25, and if there is no abnormality in the arithmetic unit 8a (excluding the multiplexer 9 and A/D converter 10), the light emitting elements L ₁ , L ₂ . . . ...will emit light one after another. In this way, when the value of the counter circuit 25 becomes "10", the output circuit 1 is output from the MPU 11.
7, the same signal as in the case of load factor 90 to 99% is output, causing the light emitting elements L ₁ to _{L 10} to emit light. On the other hand, this
The alarm device 20 is also activated by a signal from the MPU 11 to the output circuit 17, and the buzzer generates an intermittent sound.
Next, when the value of the counter circuit 25 becomes "11" and this is determined (S ₁₈ ), the MPU 11 outputs the same signal as when the load factor is 100% or more to the output circuit 17, and the light emitting element L ₁ ~ L ₁₁ is all emitted (S ₁₀ ), and the signal from this MPU 11 to the output circuit 17 causes the alarm device 20 to generate a continuous buzzer sound,
At the same time, an automatic stop output signal is generated at the automatic stop output terminal 21.

When the numerical value of the counter circuit 25 exceeds "11" and becomes "12", the numerical value becomes "11" in step 18.
It is determined that this is not the case. Then, MPU11
outputs a reset signal to the counter circuit 25, and the value of the counter circuit 25 becomes "0" (S ₂₀ ). Then, the operation returns to step _S11 again and the same operation is repeated until the inspection switch SW2 is opened.

If the arithmetic unit 8a (multiplexer 9, A/
If there is an abnormality in the parts (excluding the D converter 10), the light emitting elements _L1 to _L11 will not perform the expected light emitting operation, so this can be confirmed.

Note that in this embodiment, the light emitted from the light emitting element increases each time the value of the counter circuit increases, but by changing the way the value of the counter circuit is determined,
It is also possible to make a specific light emitting element emit light for a long time. Therefore, for example, if the duration of each light emission of a light emitting element is made longer when an alarm device is activated at the same time and an automatic stop output signal is also generated at the same time, the operation of these elements can be sufficiently inspected. be able to.

As described above, in this embodiment, a test switch and a counter circuit are provided, and when the test switch is operated, a signal is generated to cause the corresponding light emitting elements of the display device to sequentially emit light according to the numerical value of the counter circuit. In addition to inspecting itself, you can also inspect whether it is working properly. or,
In addition to the display device, the operation of the alarm device and the generation of an automatic stop output signal can also be inspected.

Further, the display device is not limited to one in which light emitting elements are arranged, and may be a digital display device.
In that case, if a numerical value is displayed appropriately according to the contents of the counter, the inspection can be performed in the same manner as in the case of a light emitting element.

Furthermore, the display element in the display device is not limited to a light emitting element, and may be a liquid crystal, a reversal plate, or the like.

Furthermore, the test program can be stored in a ROM separate from the control program.

As described above, in the present invention, a test switch and a counter circuit are provided, and when the test switch is operated, the corresponding display elements of the display device are sequentially driven according to the numerical value of the counter circuit, so that the display device itself can be tested. It is also possible to check whether the display device is working properly.

[Brief explanation of the drawing]

Figure 1 is a side view of the general structure of the crane, Figure 2 is a block diagram of the moment limiter, Figure 3 is a front view of the display device shown in Figure 2, and Figure 4 is the moment limiter shown in Figure 2. 5 is a block diagram of a moment limiter equipped with an inspection device; FIG. 6 is a flow chart for explaining the operation of the moment limiter shown in FIG. 5; 8a... Arithmetic unit, 11...MPU, 12a, 14
...ROM, 13...RAM, 17...output circuit, 18...
Selection signal generation circuit, 19...Display device, 22...Buffer circuit, 25...Counter circuit, CL...Clock, SW2...Test switch, _L1 to _L11 ...Light emitting element.

Claims (1)

[Claims] 1. A detection unit that detects the angle of the working arm of the working machine and the load applied to the working arm, and a storage means that stores a rated load value of the load applied to the working arm that is set according to the working arm length and the angle. , means for determining a value representing the degree of load applied to the working arm based on the data from the detection unit and the rated load value; a display device comprising a plurality of display elements; and a display device representing the degree of the load applied to the work arm. A moment limiter comprising a display device driving means for driving a predetermined display element in the display device according to a value,
a counter circuit for determining an arbitrary time interval; a test switch for the moment limiter; a counter value input means for sequentially inputting the numerical values of the counter circuit when the test switch is operated; representative value output means for dividing the represented value into each range of a predetermined size and outputting a representative value within the division to the display device driving means in response to the input value of the counter value input means; A characteristic moment limiter inspection device.