JPH10236800A - Safety circuit of cargo transporting machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate jumping of an operation part over the allowable value at falling of a cargo by restraining a jumping quantity when the raised state of a cargo transporting machine is at a speed over the setting, and making a flow control valve variable so as to stabilize the behavior of an arm after jumping. SOLUTION: Under the condition in which a cargo 16 falls down, after discriminating the elevatable state by a control part 14 based on signal input from a cargo detector 21, detection of the change quantity of a force sensor 12a over a properly desired value, and a detector 17, at detecting a rising speed over a proper desired value a signal to an electropneumatic proportional valve 14b is changed to input to a flow changeover valve 14c, an air flow to be fed to a cylinder 11 is changed so as to stop the cylinder 11, primary air after regulating the air pressure by a pressure regulating valve 19 is inserted into the exhaust port of the cylinder 11. For stabilizing the arm of a cargo transporting machine after stopping, after the air inserting time into the exhaust port of the cylinder 11 elapses by a set time, a solenoid valve 20 is changed to stop the air to the exhaust port.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cargo handling machine having a lifting / lowering mechanism such as a parallelogram link type or a jib type, which lifts and lowers cargo using an actuator such as an air cylinder or an electric motor. .

[0002]

2. Description of the Related Art In a conventional cargo handling machine, a lifting force of a cargo handling machine is amplified according to a force of a person having an operation unit to lift the cargo, and the cargo is lifted and lowered by the force. It was a force control method. (Japanese Patent Application No. 7-354
942)

[0003]

Here, the contents and problems of the conventional control method described above can be described as follows. When a person has an operation part and lifts a cargo, the lifting force is controlled by the operation part. The load is detected by the force sensor provided on the arm, and the lifting force is amplified to raise and lower the cargo.When the light cargo falls, the operation unit located at the tip of the arm within the range of human power Although the amount of bouncing could be reduced, as the load became heavier, it was not possible to suppress the bouncing by human power, and there was a problem that the machine would jump up to the upper limit of the machine. That is,
Although the signal of the force for lifting the cargo and the cargo are kept in balance, the falling of the cargo causes the balance to be lost and the cargo to rise suddenly. Also,
If the lifting of the cargo is failed or the force sensor is abnormal, a signal of the lifting force corresponding to the weight of the cargo is input.
Actually, there is a problem that the cargo handling machine jumps to the upper limit because there is no cargo. Further, when a damper is used to suppress the jump in the force control, there is a problem that the lifting force of the person becomes heavy or a delay is delayed from the intention of the person, which hinders the work.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems and disadvantages, and comprises a mechanism for lifting and lowering cargo, a drive source for driving the lifting mechanism, and a control source for the drive source. Control unit and an operation unit for detecting the magnitude of the lifting force that is output when a person has the operation unit and tries to lift the cargo by a force sensor provided in the operation unit. In a cargo handling machine that has a force control method that amplifies the lifting force of the cargo handling machine according to the size and raises and lowers the cargo with the lifting force and the lifting force, the falling of the cargo is detected by the cargo detector Or, if the change is detected by the amount of change exceeding the setting of the lifting force, the lifting condition of the material handling machine due to the falling of the material is determined, and when the speed exceeding the setting is detected, the output signal to the electro-pneumatic proportional valve is cut off and the cylinder is shut off. D from Suppresses faster to bounce amount evacuation of over a safety circuit of handling product transporter, characterized in that the control valve to stabilize the behavior of the arms of the handling thereof transporter after jumping by varying.

Next, an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a conceptual diagram of the embodiment. One end of an A-arm 4 is fixed to a fixed shaft 5 on a side plate of a main body 3 connected to a support 1 and a swivel 2, and the other end of the A-arm 4 is connected to a one end of a C-arm 7 via a support shaft 6. And link arm 8 and B
The arm 9 and the A-arm 4 and the C-arm 7 form a parallel link mechanism. In addition, a guide is provided for supporting the power point 10 of the parallel link mechanism in a direction perpendicular to the rotation axis of the swivel base 2, and the power point 10 of the parallel link is further moved by a cylinder 11 that can move up and down in parallel to the rotation axis of the swivel base 2. The C-arm 7 is moved up and down, and an operation unit 12 incorporating a force sensor 12a and a grip 12b is disposed at the other end of the C-arm 7.
Is provided with a hook 13 for hanging the cargo 16. Describing the control configuration, an operation unit 12 incorporating a force sensor 12a and a grip unit 12b is disposed at the tip of the C-arm 7, and the operation unit 12 is provided with a hook 13 for hanging a cargo 16. Further, the control unit 14 includes a control board 14a and an electropneumatic proportional valve 14b, and the force sensor 12a and the cargo detector 21 are connected via the electric wires 15 and 18a.
The detectors 17 provided at the upper and lower stroke portions of the cylinder 11 output signals to the control board 14a via electric wires 17a. Furthermore, the electric signal from the control board 14a is output to the electropneumatic proportional valve 14b. The electropneumatic proportional valve 14b is connected to the air source and the cylinder 11 via air pipes, respectively. A pressure adjusting valve 19 for adjusting pressure from the primary air and a solenoid valve 20 are connected to an exhaust port of the cylinder 11 via an air pipe. The solenoid valve 20 switches air by an electric signal from the control board 14a.

FIG. 2 is a block diagram of the control method. F1
Is a lifting force that is output when a human is operating. The lifting force is input to the control board 14a of the control unit 14 via the electric wire 15, is subjected to arithmetic processing, and is output to the electropneumatic proportional valve 14b. Since air proportional to F1 is constantly supplied, the lifting force F2 is supplied via the arm mechanism.
Is occurring. The control unit 14 controls the cylinder 1
1 is detected by the detector 17 and a signal is input via the electric wire 17a to determine the up / down state. At the same time, the flow rate of air supplied to the cylinder by the output from the control unit 14 is varied by the flow rate switching valve 14c. Further, the control unit 14
Controls the electromagnetic valve 20 that switches air to the exhaust port of the cylinder 11.

FIG. 3 shows a waveform of a voltage signal and a speed waveform with respect to a time axis in the conventional art, and the balance of the weight of the cargo W = (the lifting force F1 of the human being + the lifting force F2 of the cargo handling machine). It is when the cargo 16 drops from the state where it is in the state. “a” is a voltage signal of the force sensor 12a, and “b” is a voltage signal of the input to the electropneumatic proportional valve 14b calculated by the control unit 14. Further, c is a velocity waveform indicating the vertical movement of the cylinder 11.

FIG. 4 shows a waveform of a voltage signal and a speed waveform with respect to a time axis according to the present invention.
= (Human lifting force F1 + lifting force F2 of the cargo handling machine) when the cargo 16 falls. a is the force sensor 12 as in FIG.
a is the voltage signal. Further, d is a voltage signal input to the electropneumatic proportional valve 14b after being processed by the control board 14a, and e
Is a cylinder 11 controlled to suppress the amount of bouncing
5 is a velocity waveform showing the vertical movement of.

[0009]

From the above structure, the operation will be described with reference to FIG. 1. First, when the grip portion 12b is lifted upward, the force in the antigravity direction is transmitted to the force sensor 12a. The force sensor 12a converts the received force into an electric signal, is input to the control board 14a of the control unit 14 through the electric wire 15, and is subjected to integral amplification processing by the control board 14a.
Since the electric signal subjected to the integral amplification processing by the control board 14a is input as it is to the electropneumatic proportional valve 14b, the cylinder 11 is constantly supplied with air pressure proportional to the electric signal from the force sensor 12a. . Next, cargo 1
In a state in which the load sensor 6 has dropped, when the signal from the cargo detector 21 is input or when the electric signal of the force sensor 12a decreases and the change amount of the force sensor 12a becomes more than desired, the control unit 14 detects it. In addition, when the controller 14 determines the ascending / descending state based on a signal from the detector 17 and detects a speed that is more than desired as required for ascending, the controller 14 switches the electric signal to the electropneumatic proportional valve 14b, and also switches to the flow switching valve 14c. The movement of the cylinder 11 is controlled and stopped by varying the flow rate of the air supplied and supplied to the cylinder 11. Further, the primary air is adjusted in air pressure by a pressure adjusting valve 19, and the air exhausted from the cylinder 11 is switched by an electromagnetic valve 20 at the same time as the detection, and the pressure-adjusted primary air is inserted into an exhaust port of the cylinder 11. In order to stabilize the air insertion time into the exhaust port of the cylinder 11 after the arm of the cargo handling machine is stopped, when the set time which is a timer in the control board 14a is reached, the solenoid valve 20 is used to switch over the air outlet time. Air has been stopped. By slightly lowering the grip portion 12b in the direction of gravity, the controller 14 determines the state of ascending or descending by a signal from the detector 17, and when the speed becomes equal to or higher than the set descent,
By outputting to the flow switching valve 14c to vary the air flow,
Normal lifting operation is performed.

3 and FIG. 4, when a person lifts and holds the cargo 16 with the cargo carrier, FIG. 3 shows the conventional force. This is a control method, and the voltage signal a from the force sensor 12a is
It is a waveform which showed the process in which the cargo 16 dropped from the state (part A) which lifted the cargo 16 and stopped. At this time, the voltage signal b calculated by the control unit 14 is converted to the electropneumatic proportional valve 14b.
, And the air pressure of the cylinder 11 is controlled by the electro-pneumatic proportional valve 14b, and the cargo handling machine is moved up and down. Part B indicates the elapsed time in which the cargo 16 drops from the stopped state, the cylinder 11 rises, and stops at the upper limit. In FIG. 4, which is a control according to the present invention, the voltage signal a from the force sensor 12a is a waveform showing a process in which the cargo 16 is lifted up and stopped from a stopped state (portion C). At this time, d detects the amount of change in the force of the force sensor 12a when the load is detected by the cargo detector 21 in the controller 14, and determines the ascending state due to the drop of the cargo 16 and detects a speed higher than the set value. This is an input signal to the electropneumatic proportional valve 14b at this time. At the same time, the pressure of the primary air is adjusted by the pressure adjusting valve 19, and the pressure is switched by the solenoid valve 20, inserted into the exhaust port of the cylinder 11, and the velocity waveform e showing the vertical movement of the cylinder 11 when the flow rate switching valve 14c is changed. It is. Part D shows a series of elapsed time during which the cargo 16 drops from the stopped state, the cylinder 11 rises, and stops. Therefore, the speed waveform e has a shorter elapsed time until it stops than the speed waveform c in FIG. 3, and the amount of jumping when the cargo 16 falls has been reduced, so that a human can operate more safely.

[0011]

According to the above configuration and operation, the effects can be described. By using the control method according to the present invention in the conventional force control method, the load can be lifted under some circumstances while the load is being lifted. Even if it falls, the operation part held by humans does not jump more than it can tolerate, it can be stopped safely, and the behavior of the arm after jumping will be stable, which will also hinder the next work And a great effect can be obtained in terms of safety that operation is possible.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing an embodiment of the present invention.

FIG. 2 is a functional explanatory diagram (block diagram) of an embodiment of the present invention.

FIG. 3 is an explanatory view of a conventional actual waveform.

FIG. 4 is an explanatory diagram of actual waveforms according to the embodiment of the present invention.

[Explanation of symbols]

1 support 2 swivel 3
Main unit 4 A arm 5 Fixed shaft 6
Support shaft 7 C arm 8 Link arm 9
B arm 10 Power point 11 Cylinder 12
Operation unit 12a Force sensor 12b Grip unit 13
Hook 14 Control unit 14a Control board 14
b Electro-pneumatic proportional valve 14c Flow switching valve 15 Electric wire 16
Cargo cargo 17 Detector 17a Electric wire 18
Grip detector 18a Electric wire 19 Pressure regulating valve 20
Solenoid valve 21 Cargo load detector F1 Human lifting force (force in anti-gravity direction) F2 Lifting force of cargo carrier W Weight of cargo

Claims (2)

[Claims] An apparatus has a mechanism for lifting and lowering a cargo, a drive source for driving the lifting mechanism, a control unit and an operation unit for controlling the drive source. The magnitude of the lifting force in the anti-gravity direction that is issued when trying to lift is detected by a force sensor provided on the operation unit, and the lifting force of the cargo handling machine is amplified according to the magnitude of the lifting force, and In a cargo handling machine having a force control method of lifting and lowering a cargo with a lifting force and a lifting force, a drop of the cargo is detected by a cargo detector or a change amount equal to or greater than a setting of the lifting force, and the load of the cargo is detected. When the lifting condition of the cargo handling machine due to the fall is determined and the speed exceeding the setting is detected, the output signal to the electro-pneumatic proportional valve is shut off, the air is quickly exhausted from the cylinder to suppress the amount of jumping, and the flow switching valve Variable Safety circuit handling product transporter, characterized in that to stabilize the behavior of the arms of the handling thereof transporter after jumping at things. 2. The method according to claim 1, further comprising the step of adjusting the air to be inserted into the exhaust port of the cylinder by means of a pressure regulating valve and a solenoid valve when the falling of the cargo is detected, thereby suppressing the amount of jumping. Safety circuit for cargo handling machine as described.