JPH0818798B2 - Balance handling equipment safety device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a balanced cargo handling apparatus that elevates and lowers a heavy load by an operator by applying a small force to the heavy load. Relates to a safety device for preventing the ropes and arms of the cargo handling device from jumping and dropping.

[Conventional technology]

In a balanced cargo handling device, when a load is suddenly applied with a heavy load or when the load loses its support and is in a state of zero removal, the ropes and arms are Jumping and jumping is very dangerous and it is necessary to take safety measures for it.

As a conventional jump-prevention device, for example, the actual Kaisho 56-
No. 6900, in this device, a rod is inserted into a pipe rod connected to a piston that applies thrust to an arm that supports a load, and the pipe rod is passed through a fluid substance control device provided at the tip of the rod. The inside is divided into two empty chambers, and the mechanical structure is such that a single-acting cylinder filled with fluid is filled in the empty space on the distal end side for about 8 minutes and the empty space on the proximal end side. It is designed to prevent jumping at the time of sudden unloading.

[Problems to be solved by the invention]

However, this conventional device has a disadvantage that it cannot be used in a balanced cargo handling device having a different configuration for raising and lowering a load because the jumping prevention mechanism is configured by partially utilizing the configuration for raising and lowering a load. Also, since the jumping prevention is realized by the mechanical structure, there is a problem that the device becomes large in size.

The present invention has been made in view of these circumstances, accurately detects a sudden load or a sudden unloading with a simple configuration, and based on this detection output, makes an emergency stop of the electric motor for driving the load to prevent jumping. It is an object of the present invention to provide a safety device for a balanced cargo handling device, which is prevented in advance.

[Means for solving problems]

In the first invention, a suspended load lifting mechanism for lifting a suspended load,
An actuator for driving the hanging load lifting mechanism, a weight sensor arranged in the vicinity of a portion of the hanging load lifting mechanism for hanging a load, and a weight detected by the weight sensor to store the weight of the hanging load, A storage unit that outputs a command value corresponding to the stored value, and a drive control unit that calculates a deviation between the command value output from the storage unit and the output of the weight sensor and drives the actuator based on the deviation. In the parallel cargo handling apparatus, acceleration detecting means for detecting the acceleration of the suspended load, calculating means for obtaining the actual weight of the suspended load based on the output of the acceleration detecting means and the output of the weight sensor, and the calculating means. Output is compared with the stored weight of the storage means, and a sudden unloading or a sudden load is detected based on the comparison result. So that comprise a stop means for performing a predetermined process stopping Yueta.

In the second invention, a hanging load lifting mechanism for lifting a hanging load,
An actuator for driving the hanging load lifting mechanism, a weight sensor arranged in the vicinity of a portion of the hanging load lifting mechanism for hanging a load, and a weight detected by the weight sensor to store the weight of the hanging load, A storage unit that outputs a command value corresponding to the stored value, and a drive control unit that calculates a deviation between the command value output from the storage unit and the output of the weight sensor and drives the actuator based on the deviation. In the parallel cargo handling device, the acceleration detecting means for detecting the acceleration of the suspended load, the actuator speed detecting means for detecting the driving speed of the actuator, and the suspension based on the output of the acceleration detecting means and the output of the weight sensor are suspended. The calculation means for obtaining the actual weight of the load is compared with the output of the calculation means and the stored weight of the storage means, and the detected actuation A stopping means that compares the user drive speed with a predetermined threshold value, detects a sudden unloading or a sudden load based on the results of the two comparisons, and performs a predetermined process to stop the actuator when a sudden unloading or a sudden load is detected. I am trying to prepare.

[Action]

The first invention relates to detection of sudden unloading or sudden load in a balanced cargo handling apparatus and subsequent processing, in which the actual weight of the load obtained based on the suspended load acceleration and the output of the weight sensor is stored in a memory type. The weight of the load is compared with the weight of the load, and the sudden unloading or the sudden load is detected based on the result of the comparison. When the sudden unloading or the sudden load is detected, the actuator is stopped.

According to a second aspect of the invention, the calculated actual weight of the load is compared with the weight of the load stored in the storage means, the actuator driving speed is compared with a predetermined threshold value, and the rapid unloading is performed based on the results of both comparisons. Or it is designed to detect a sudden load,
This prevents erroneous detection of sudden unloading or sudden load when the detection value of the weight sensor suddenly changes due to an artificial cause.

〔Example〕

Hereinafter, the present invention will be described in detail according to embodiments shown in the accompanying drawings.

 FIG. 1 shows an embodiment of the present invention.

In this balanced cargo handling apparatus, when the load 1 is raised or lowered, the speed command signal Vi is usually generated by operating the operation lever 2. The speed command signal Vi is input to the addition point 4 via the changeover switch 3, and at the addition point 4, a deviation (Vi-V) from the detection signal VN of the rotation speed detector 5 is input.
N) is taken. The proportional-plus-integrator circuit 6 adds a PI operation based on the transfer function (Kp + KI / S) to the deviation (Vi-VN), and outputs the output to the drive circuit 7. The drive circuit 7 rotates the electric motor 8 by this input signal. As a result, the drum 9 rotates, and the rope 10 is wound up or unwound, so that the load 1 moves up or down at a designated speed.

In this way, when the load 1 is appropriately raised by operating the operation lever 2 and then the operation lever 2 is returned to the neutral position, the speed command signal Vi becomes zero, and as a result, the load 1 is stopped in the suspended state. . When the operation lever 5 is returned to the neutral position, the weight storage unit 11 (corresponding to the storage means in the claims) takes in the detection value T of the weight sensor 12, and the switching circuit 3 sets its contact point to the operation lever 2 side. To the weight storage unit 11 side. The detection value T of the weight sensor 12 when the suspended load is stationary corresponds to the own weight w of the suspended load 1, and therefore the weight w of the suspended load is stored in the weight storage unit 11.

In this state, if the operator applies a very small force f upward to lift the load, the weight sensor 12 detects the tension T (= w-f) at that time. This detection value T is input to the addition point 13, and at the addition point 13, the deviation (T-w) between the detection value T and the stored value w of the weight storage unit 11 is obtained. At this time, since the detection value T of the weight sensor 11 is (w-f), the value output from the addition point 9 becomes (w-f-w), that is, the operating force (-f). This operating force (-
f) is subjected to force / velocity conversion and then input to the addition point 4 via the switching circuit 3, and the deviation from the feedback signal VN is taken at the addition point 4. This deviation is input to the drive circuit 7 via the proportional-plus-integral circuit 6, and the drive circuit 7 drives the electric motor 8 to rotate the drum 9 and the load 1 at a speed corresponding to the applied operating force f. Rises quickly. The configuration including the addition point 13 and the drive circuit 7 corresponds to the drive control means in the claims.

The above is the normal lifting / lowering operation of the load, but when the load 1 is in an equilibrium state, the rope 10 that suspends the load 1 suddenly breaks for some reason, or the hook that suspends the load 1 suddenly breaks. In this case, the load 1 that has been suspended up to now will not only drop suddenly, but the rope 10 or arm (in the case of a cargo handling device with a link mechanism) that is suspending the load 1 will jump suddenly upward, which is extremely dangerous. is there.

Therefore, in the embodiment shown in FIG. 1, the rapid unloading load determination circuit 20 immediately determines the rapid unloading or the rapid load, and when the rapid unloading load is detected, the brake 22 is applied via the brake drive circuit 21. The brake 22 is driven to immediately stop the rotation of the electric motor 8.

The output of the acceleration sensor 23 (corresponding to the acceleration detecting means in the claims), the stored data w of the weight storage unit 11 and the output T of the weight sensor 12 are input to the sudden load determination circuit 20. The unloading judgment circuit 20 detects sudden unloading and sudden load using these input data. The detection principle will be described with reference to FIG.

In Fig. 2, m ₁ is a tare (bracket or hook)
Mass, m ₂ is the mass of the load 1, W ₁ is the weight of the tare, W ₂ is the weight of the load 1, T is the output of the weight sensor 13, f shows a human operation force.

The equation of motion when the load 1 is being lifted up and down by the operating force f applied by a person can be expressed as the following equation (1).

(M ₁ + m ₂ ) = T + f− (w ₁ + w ₂ ) ... (1) ... Acceleration of load When the load is in the equilibrium state with no human operating force f applied, the above formula (1) becomes It becomes like the following formula (2).

(M ₁ + m ₂ ) = T− (w ₁ + w ₂ ) ... (2) In this state, the weight value stored in the weight storage unit 11 is
It becomes w ₁ + w ₂ .

Now, when the rope or hook is cut and the mass m _{2 of the} load 1 suddenly disappears, the above equation (2) becomes like the following equation (3).

m ₁ = T−w ₁ (3) In the above formula (3), when substituting m ₁ = W ₁ / g (g: gravitational acceleration) for deformation, Then, w ₁ = Tg / (+ g) (4) holds.

In the above formula (4), T is the output from the weight sensor 12, is the output from the acceleration sensor 12 provided in the weight sensor unit 12, and g is known. The weight at the moment of loading, ie w ₁ , can be calculated. In addition, what can be calculated by this equation (4) is
Not only w ₁ , but the weight when the load is in equilibrium, that is, w ₁
Of course, + w ₂ can also be obtained. This will be clear from the fact that the same relational expression as the expression (3) holds when m ₁ + m ₂ = m and w ₁ + w ₂ = w in the expression (2).

That is, the weight obtained from the above equation (4) indicates the actual weight of the load at each time point, and in the sudden load determination circuit 20, as shown in FIG. The load weight wx (= Tg / + g) is constantly calculated from the output w of the weight sensor 12 (steps 100 and 110). Then, the sudden load determination circuit 20 compares the calculated load weight wx with the stored weight w of the weight storage unit 11 (step 120).

As described above, since the weight storage unit 11 stores the sum of the weight w ₂ of the suspended load and the weight w ₂ of the tare (w ₁ + w ₂ ) as the stored weight w, the suspended load 1 is normally suspended. When the suspended load 1 is suddenly unloaded for some reason, the above comparison results are inconsistent.

Therefore, in the sudden load determination circuit 20, the above step 120
When the comparison result in (1) is inconsistent, it is regarded as a sudden unloading or a sudden load, and a brake command is input to the brake drive circuit 21 (step 130). By inputting this command, the brake drive circuit 21 drives the brake 22 mounted on the output shaft of the electric motor 8. As a result, the electric motor 8 is stopped,
The jumping of the cargo handling device is prevented in advance. in this way,
The sudden load determination circuit 20 functions as the calculating means and the stopping means in claim (1).

In the above-described embodiment, the sudden load is determined based on whether the stored weight w and the calculated weight wx match or not. However, in an actual machine, there is some variation in the detection output of acceleration or weight. Therefore, an appropriate threshold value e may be set, and when | wx−w |> e, it may be determined that a sudden unloading or a sudden load has occurred.

In the above embodiment, the output shaft of the electric motor is stopped by the brake when the sudden load is detected to prevent jumping. However, when the manual operation is performed, the switching circuit 3 connected to the weight storage unit 11 side is used. The speed command applied to the addition point 4 may be set to zero by switching to the operation lever 2 side, and thereby the electric motor 8 may be quickly stopped.

 FIG. 4 shows another structural example of the present invention.

The configuration shown in FIG. 4 is intended to prevent the device from jumping or dropping due to a sudden load in the work of fitting the load 31 with holes into the fixed pin 30.
Since the normal raising / lowering operation is the same as that of the configuration shown in FIG. 1, the duplicated description will be omitted.

If the difference between the diameter of the pin 30 and the diameter of the hole 32 of the load 31 is small during the pin fitting work, move the load 32 laterally to move the hole 32
During the step of pushing the pin 30 in, the weight sensor 12 detects a minute force due to galling, stick-slip between the pin and the hole, etc., and as a result, the electric motor 8 tries to rotate.
However, in this state, since the load 31 is fixed by the pin 30, the rope 10 can hardly move. As a result, the force with a rapid change rate is detected by the weight sensor 12.

When considering the safety of the equilibrium cargo handling device, it is necessary to take measures to prepare for sudden load and unload during equilibrium control.Because a large change occurs in the output of the weight sensor 12 during sudden unload, the weight sensor 12 The rapid removal load can be detected by determining the change rate (differential value) of the output. However, during the pin fitting work, a force with a large rate of change is detected by the weight sensor 12 due to the above-mentioned cause,
If the sudden load is determined from the rate of change of the output of the weight sensor 12, it is impossible to distinguish between the artificially applied force and the sudden load.

Therefore, in the configuration shown in FIG. 4, the sudden load determination circuit 40 includes the rotation speed VN of the electric motor 8 detected by the rotation speed detector 5 (corresponding to the actuator speed detection means in the claims) and the weight. The detection value T of the sensor 12 and the stored data w of the weight storage unit 11 are input.

When the pins are engaged, the load 31 is fixed to the ground as described above, and therefore the rotation speed VN of the electric motor 8 is almost zero. However, when the load is suddenly removed, the load 31 suddenly disappears. Shows a high rotation speed and winds up the rope 10.

On the contrary, when the load is suddenly increased, the load rapidly increases, so that the electric motor 8 lowers the rope 10 at a high rotation speed.

When the load is suddenly removed, the suspended load stored in the weight storage unit 11
The weight w of 31 and the detection output T of the weight sensor 12 are largely different, and these relationships are also used for the determination of the sudden load.

FIG. 5 shows an example in which the sudden load determination circuit 40 is configured by hardware. The detection output T of the weight sensor 12 is shown in FIG.
The stored data w of the weight storage unit 11 is input to the subtractor 41. The subtractor 41 takes the difference T-w between these two signals and inputs this to the absolute value comparator 42. The absolute value comparator 42 takes the absolute value | T−w | of the input difference T−w, compares it with a predetermined set value ε _H, and sets “1” when | T−w |> ε _H. , | T−w |
When <ε _H , “0” is output to the AND circuit 43. The set value ε _H is a value corresponding to a force that cannot be applied by a human.

The detected value VN of the rotation speed sensor is the absolute value comparator 44.
Is input to The absolute value comparator 44 is the absolute value of the input value VN |
VN | is taken and compared with a predetermined set value ε _M , | VN |
It outputs “1” to the AND circuit 43 when> ε _M and outputs “0” when | VN | <ε _M.

The AND circuit 43 takes the logical product of the two input signals and outputs the output to the switching circuit 3.

That is, the sudden load determination circuit 40 determines that the difference between the output T of the weight sensor 12 and the suspension load amount w stored in the weight storage unit 11 is larger than a predetermined threshold value ε _H and the motor rotation speed V is high.
When N is larger than a predetermined threshold value ε _M, it is judged as unloading,
This determination signal is output to the switching circuit 3.

In this balanced cargo handling device, when the operation lever 2 is in the neutral position, the switching circuit 3 is connected to the weight storage section 11 side to keep the load in a balanced state.
When the sudden load detection signal is output from 40, the switching circuit 3 immediately switches its contact to the operation lever 2 side, and the device is controlled by the speed command from the operation lever 2, thereby the rope, Try to prevent the jumping of the arms. In this way, the sudden load determination circuit 40 functions as the calculating means and the stopping means in claim (2).

In this embodiment as well, as shown in FIG. 1, the device may be brought to an emergency stop by a brake provided on the electric motor during a rapid unloading load.

 FIG. 6 shows still another configuration example of the present invention.

The apparatus shown in FIG. 6 holds a load 51 with a hand 50, and the hand 50 is opened and closed by the expansion and contraction operations of the cylinders 52 and 53. Each cylinder 52,53 is a pneumatic switching valve 54
(The one on the cylinder 53 side is not shown). This switching valve 54 is switched by a signal from the hand open button 56 and the hand close button 57 provided on the operation box 55. When the hand open button 56 is turned on, the switch valve 54 is switched to the A side and the air pressure source 58 of the air pressure source 58 is switched. Air flows into the head side of the cylinder 52 and the hand 50 is opened. Hand close button
When 57 is turned on, the switching valve 54 switches to the B side,
As a result, the air from the air pressure source 58 flows into the bottom side of the cylinder 52, and the hand 50 is closed.

In such a device, when the changeover switch circuit 3 is connected to the d side and the operator pushes the hand open button 56 to put the load 51 down when the load 51 is raised and lowered by manual operation, 50 is opened and the load being gripped 51
At this time, the load weight detected by the weight sensor 12 and the data stored in the weight storage unit 11 (hand
There is a large difference between the weight of 50 and the weight of the load 51), so that the command value input to the electric motor 8 becomes large, and as a result, the rope 10 or the arm jumps up and down.

Therefore, in the switch switching control circuit 60, the hand open signal SH output from the hand open button 56 is input, and when this AND open signal is turned on, the section of the switch circuit 3 connected to the d side is immediately output. and to switch to the c side (FIG. 7 (a) (b) see, time t ₁ or t _3).
When the switch circuit 3 is switched to the c side, the electric motor 8 does not operate unless the operating lever 2 is moved. Therefore, the hand 50 stops at the position at which the hand open button 56 is turned on, and the cargo handling device jumps. Can be prevented.

After the load 51 is released by the above processing, the device is stationary and the hand 50 can be moved up and down by the operating lever 2. In this state, it is not possible to apply force to the hand 50 to manually move the device. In some cases, it may be desirable to immediately touch the hand 50 to move the device.

Therefore, the switch switching control circuit 60 is provided with the operation lever 2
When the speed command Vi generated by is input and the switch switching control circuit 60 detects a non-zero value in the speed command Vi after the hand open button 56 is turned on, the speed command Vi becomes zero again. After a lapse of a predetermined time ta, the contact piece of the switching circuit 3 is switched from the c side to the d side at this elapsed time (t _{2 in} FIG. 7). The predetermined time ta is a time required for the storage operation of the weight storage unit 11, and the weight storage unit 11 indicates the speed command Vi after the hand open button 56 is pressed.
If the displacement of the operating lever 2 is detected by the
The weight of the hand 50 is stored again by taking in the 12 detected values.

After the switching circuit 3 is switched to the d side by such processing, the operator can freely move the device by touching the hand 50.

Thus, in the balanced cargo handling apparatus shown in FIG. 6, when the hand open button 56 is pressed in the balanced control state in which the switching circuit 3 is connected to the d side, the switching circuit 3 is immediately c.
Since it is switched to the lever control on the side, jumping of the hand or rope can be prevented. Also, in this device, after the hand open button 56 is turned on, the operation lever 2
Is displaced, the data in the weight storage unit 11 is updated, and the switching circuit 3 is switched from the c side to the d side after the data is updated, so that the speed control is switched to the equilibrium control efficiently. be able to.

In a device equipped with a suction cup instead of the hand 50, the suction force off signal generated when the suction force of the suction cup is turned off may be used instead of the hand opening signal.

〔The invention's effect〕

As described above, according to the present invention, the load weight at each time point obtained by calculation is compared with the prestored load weight. Since the emergency stop is performed, it is possible to easily and surely prevent a sudden drop or jump of the rope or arm. Further, in the present invention, the actual weight of the calculated load is compared with the stored weight of the load, and the actuator driving speed is compared with a predetermined threshold value. Therefore, it is possible to reliably prevent erroneous detection of sudden unloading or sudden load when the detection value of the weight sensor suddenly changes due to an artificial cause.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a conceptual diagram showing a principle of detecting a sudden load in the embodiment.
FIG. 3 is a flow chart showing the operation of the same embodiment, FIG. 4 is a block diagram showing another example of the present invention, and FIG. 5 is a block showing an internal configuration example of the sudden load determination circuit in the configuration of FIG. 6 and 6 are block diagrams showing still another example of the present invention, and FIG. 7 is a time chart for explaining the operation thereof. 1,31,51 …… Suspended load, 2 …… Operating lever, 3 …… Changeover switch circuit, 4,13 …… Addition point, 5 …… Rotation speed detector,
6 ... Comparative integration circuit, 7 ... Drive circuit, 8 ... Electric motor, 9 ... Drum, 10 ... Rope, 11 ... Weight storage section,
12 ... Weight sensor, 20,40 ... Sudden load load judgment circuit, 21 ...
… Brake drive circuit, 22 …… Brake, 30 …… Pin, 32
...... Hole, 50 ...... Hand, 52,53 ...... Cylinder, 54 ...... Air type switching valve, 56 ...... Hand opening switch, 60 ...... Switch switching control circuit

Claims (2)

[Claims] 1. A hanging load lifting mechanism for lifting a hanging load, an actuator for driving the hanging load lifting mechanism, a weight sensor arranged in the vicinity of a portion of the hanging load lifting mechanism for hanging a load, and a weight sensor for the weight sensor. The storage means stores the weight of the suspended load by taking in the detected value and outputs a command value corresponding to the stored value, and a deviation between the command value output from the storage means and the output of the weight sensor. In a parallel cargo handling apparatus comprising drive control means for driving the actuator based on the obtained deviation, an acceleration detecting means for detecting an acceleration of a hanging load, and a hanging operation based on an output of the acceleration detecting means and an output of the weight sensor. The calculation means for obtaining the actual weight of the load applied is compared with the output of the calculation means and the storage weight of the storage means, and the rapid unloading or the rapid load is detected based on the comparison result. And, the safety device of the balancing handling device comprising a stop means for performing a predetermined process stopping the actuator when the rapid unloading or sudden load is detected, the. 2. A lifting load lifting mechanism for lifting a lifting load, an actuator for driving the lifting load lifting mechanism, a weight sensor arranged in the vicinity of a portion of the lifting load lifting mechanism for hanging a load, and a weight sensor for the weight sensor. The storage means stores the weight of the suspended load by taking in the detected value and outputs a command value corresponding to the stored value, and a deviation between the command value output from the storage means and the output of the weight sensor. In a parallel cargo handling apparatus comprising drive control means for driving the actuator based on the obtained deviation, acceleration detection means for detecting an acceleration of a suspended load, actuator speed detection means for detecting a drive speed of the actuator, and the acceleration Calculating means for obtaining the actual weight of the suspended load based on the output of the detecting means and the output of the weight sensor, and the output of the calculating means and the storage When the detected actuator driving speed is compared with a predetermined threshold value and the sudden unloading or the sudden load is detected based on the comparison result of both, and the sudden unloading or the sudden load is detected. A safety device for a balanced cargo handling device, comprising: stop means for performing a predetermined process for stopping the actuator.