JPH0546291B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an automatic control device for a tension jack for prestressed construction work, and more specifically, a tension jack for prestressed construction work that can detect the stroke amount of the tension jack without contacting the stroke. This invention relates to an automatic control device.

[Prior Art] In conventional tensioning work for prestressed steel materials, tensioning work is one of the important steps in introducing a predetermined tension force into a concrete structure and fully demonstrating the performance of the prestressed concrete structure.

However, in this stressful work, specialized workers rely on intuition and experience to open and close hydraulic valves, measure the load with a pressure meter, measure elongation with a scale, and check while writing on the control grabber. Currently, the load is increased in stages up to a predetermined load. In this type of method, the final control is a check after the tension work, so the group management values cannot be reflected in the individual tension work, and the creation of the management graph is done manually, which can lead to errors. There were problems such as it took time and required a large number of workers (including the person creating the tension management graph) because the tension work was done while drawing the management graph.

Therefore, in order to solve the above problems, and to deal with the rising cost of specialized labor, which has become a particular problem in recent years, and to manage strict tension mainly in PC containment vessels at nuclear power plants, we will use computers to automatically manage tension and control. is about to be introduced. Prestress tensioning technology based on automatic tensioning and automatic management is still in its early stages, and complete systemization has not yet been achieved.Only automatic management systems that are easy to develop are used, and tensioning (hydraulic jack operation) Currently, we rely on manual operations. By introducing a large computer, automatic tensioning and online
Although it is conceivable to enable automatic management, there are disadvantages in that the device becomes larger and costs increase, and that on-site workers without specialized knowledge cannot easily and quickly carry out tension work.

Therefore, the present inventors previously proposed in Japanese Patent Application No. 61-186526 an automatic tensioning system for prestressing steel that can perform prestress tensioning at low cost and without the need for large-scale equipment or specialized engineers. A control technology was proposed.

The present inventors continued their research in order to further improve the previously proposed technology and obtained the following knowledge.

In other words, the previously proposed technology eliminates tension and jerkiness.
A method is adopted in which the amount of stroke movement is measured using a potentiometer displacement type or the like. Specifically, the displacement model is fixed to the jack body, and the tip of the spindle is touched on a part of the jack stroke so that the spindle moves following the movement of the stroke, and the amount of movement is measured electrically. This is converted into a signal and detected as a displacement amount.

However, since this type of displacement type has a long outer diameter (the maximum extended length is more than twice the stroke), a strong and large cover is required to prevent damage, which results in an increase in the weight of the jack. It was found that handling was inconvenient.

In addition, the measurement accuracy of tension jack and stroke is 1
It is sufficient if the accuracy is secured in mm, but the accuracy of this type of displacement type is approximately 1/50 mm or more (commercially available)
Therefore, it was found that a displacement type with higher precision than necessary had to be used, making it that much more expensive.

Furthermore, Japanese Patent Application Laid-open No. 58-198705 discloses a displacement meter in which a tilted reflective surface is fixed to an object whose displacement is to be detected as a part to be measured, and light is projected onto the tilted reflective surface which is the part to be measured. describes a technique for detecting the displacement of an object based on changes in the position and/or inclination of reflected light from an inclined reflective surface. However, this technology not only requires that the inclined reflective surface be firmly fixed to the object to be detected with extremely high precision, but also detects slight changes in the tilt or position of the reflected light and measures the amount of displacement. Because of the structure, it is not only completely inappropriate but also practically impossible to apply this technique to the present invention, which is used for tensioning of prestressed steel materials.

[Object of the Invention] The object of the present invention is to provide an automatic control device for a tensioning jack for prestressing work that can perform prestress tensioning at low cost without requiring a large-scale device or a specialized engineer. Another object of the present invention is to reduce the size and weight of the device.
To provide an automatic control device for a tension jack for prestressing work, which is hard to break, convenient to handle, and capable of measuring stroke movement with necessary accuracy.

[Means for Solving the Problems] The present invention was achieved as a result of intensive research to achieve the above object.

That is, the automatic control device for a tension jack for prestressing work according to the present invention sets a hydraulic jack on a prestressed steel material placed at a predetermined position, supplies hydraulic pressure to the hydraulic jack from a hydraulic system, and applies pressure to the prestressed steel material in a predetermined position. When applying a tension force, a microcomputer device is installed at the tension site, tension management information including at least a control limit value is inputted to the microcomputer device, and then the data of the automatically measured tension force and the tension force of the hydraulic jack are inputted into the microcomputer device. In an automatic control device that controls tension by introducing measurement data of stroke movement amount, etc., comparing it with the control limit value, and transmitting a tension control signal to the hydraulic system, the direction of movement of the stroke of the hydraulic jack is determined. a part to be measured that has a scale line that is formed along the scale line and can measure the amount of movement of the stroke, a light projecting part that illuminates the part to be measured, and a scale line that is slightly smaller than the scale line at both ends of the light projecting part. and a sensor head consisting of two light-receiving parts that are set in a straight line with a predetermined angle shifted from each other to receive the reflected light, and the sensor head is configured to respond to changes in the amount of light received when passing through the graduations of the scale of the scale line. The present invention is characterized in that it includes a stroke detection device that detects the amount of movement of the stroke.

In the present invention, "setting a hydraulic jack to a prestressed steel material placed at a predetermined position" means fixing a prestressed steel material (including unbonded prestressed steel wire) to a grip or the like provided at the bottom of the hydraulic jack.
"Supplying hydraulic pressure from a hydraulic system" means supplying hydraulic pressure from a hydraulic pump via a hydraulic pressure supply pipe.

``Installing a microcomputer device at a stressful site'' means that a microcomputer device is installed at the site where the hydraulic jack is installed or in the vicinity (for example, a site office, etc.). There is a method in which a microcomputer device is installed in the equipment, inputs the measurement data, performs the necessary judgment processing, and sends the tension control signal to the hydraulic system. However, there are two methods: controlling the amount of oil from the hydraulic pump and controlling the amount of oil by operating a solenoid valve or the like provided in the hydraulic pressure supply piping.

There is also a method of directly incorporating microcomputer equipment into the hydraulic system. There are two methods of directly incorporating it into the hydraulic system: a method of incorporating it into a hydraulic pump and a method of incorporating it into the supply piping.

"Input tension management information including at least control limit values into the microcomputer device" means P-
This involves inputting tension management information including control limit values for δ management or μ management. P here
−δ control is control based on the jack load indication (prestress amount) during tension and the elongation of the PC steel.
μ control refers to controlling by setting control limits based on the friction coefficient between the prestressing steel material and the sheath.

"Inputting automatically measured tension data" differs depending on the management method, but for example, in the case of P-δ management, the load reading (prestress amount) of the jack during tension and the elongation of the prestressing steel material are automatically input. It is to measure and input.

"Measurement data of the stroke movement amount of the hydraulic jack" is data measured and detected by the stroke detection device unique to the present invention.

In order to detect this data, a part to be measured that can measure the amount of movement of the jack stroke, such as a 1 mm pitch scale line (scale) engraved on the surface of the jack stroke, or a scale line set parallel to the stroke, is used. A stainless steel scale (with graduations of 1 mm pitch) is provided, and light is directed from a light projector onto the scale lines (graduations) of the part to be measured, and the reflected light is received by the light receiving section. There is a difference in the amount of light received depending on where there is a mark and where there is no mark, and from this difference, for example, the number of times the mark has been passed is counted and converted into the amount of movement.

In the present invention, the amount of movement is detected by the relative movement between the part to be measured and the sensor head part (light emitting part and light receiving part). For example, when marking a jack stroke, , the marking moves and the sensor head remains stationary.
In addition, when setting the stainless steel scale parallel to the jack stroke, the sensor head may be fixed directly or indirectly to the jack stroke so that it moves in accordance with the movement of the jack stroke.

With the above device, the 1 mm scale required for the accuracy of the tension jack stroke can be set correctly (i.e.,
1mm accuracy), and since the sensor head part and the part to be measured are not in contact, there is no risk of them colliding with each other and being damaged, and since it is not large like conventional displacement meters, it can be made smaller and lighter.

In addition, the stroke detection device has one light emitting section and two light receiving sections provided at both ends of the light emitting section in a straight line, and the two light receiving sections are formed along the moving direction of the stroke. Since it is set slightly offset from the line by a predetermined angle, the moving direction of the stroke can also be detected.

[Example] An example of the apparatus of the present invention will be described based on FIG.

In Fig. 1, reference numeral 1 is a hydraulic jack that moves a prestressed steel material grip (not shown) according to the reciprocating motion of stroke 1A (left and right movement in the drawing) to apply tension to the prestressed steel material whose one end is fixed. .

The hydraulic jack 1 has an oil supply pipe 2 and an oil discharge pipe 3.
is connected. The hydraulic jack 1 is equipped with an ON/OFF switch for starting and a switch for tension stopping. 4 is a hydraulic pump.
5 is a personal computer with an input keyboard and display (hereinafter referred to as a personal computer);
6 is a control system (not shown, but may include a printer), 7 is a measuring device for pressure transducers and solenoid valves, which will be described later, and 8 is a data insertion unit for the amount of prestress and the amount of elongation of the prestressed steel material. , these 5 to 8 are microcomputer devices,
It may be integrated and shielded and built into the circuit board of the hydraulic pump 4, or it may be installed externally.

9 is a pressure transducer, and 10 is a solenoid valve (with a switch circuit and drive device). The pressure transducer 9 and the solenoid valve 10 are integrated into the hydraulic pump 4. The opening/closing and opening/closing time of the solenoid valve 10 is controlled by a personal computer via a control system 6.
11 is a stroke detection device. Reference numeral 12 denotes a control cable, which is used here to transmit signals for opening and closing the electromagnetic valve from the computer 5.

In the present invention, the above-mentioned apparatus can be made into a unit to obtain a compact apparatus as shown in FIG.

In FIG. 2, 50 is a hydraulic pump unit, which includes a hydraulic pump, an oil tank 41, a hydraulic hose connector 42, and the like.

Reference numeral 60 denotes a control section provided at the upper part of the hydraulic pump unit 50, which includes microcomputer equipment such as a personal computer, a control system, measuring equipment, and a data insertion section.

It is preferable that a caster 43 is attached below the hydraulic pump unit 50 so that the apparatus unit including the hydraulic pump unit 50 and the control section 60 is configured to be movable.

The hydraulic jack 1 is connected to an oil supply pipe 2 and an oil discharge pipe 3, and a sensor head 30 is provided near the hydraulic jack 1. Note that it is preferable that a hand switch is provided. 40 is a cable.

The stroke detection device will be explained in detail below with reference to FIGS. 3 to 5.

In FIG. 3, the configuration of the sensor head section 30 includes a light projecting section 31 and a light receiving section 32. Light projecting section 3
1 is made of plastic fiber (or glass) of about 1 mmφ, and the light receiving part 32 is made of plastic fiber (or glass
They are mounted on the surface of a stainless steel scale 33 facing each other at a certain distance δ, and two light receiving sections 32 are installed at both ends of the light emitting section 31.
A, 32B are provided.

The light emitted from the light projecting section 31 is reflected by the surface of the scale 33 and is captured by the light receiving section 32. By moving the sensor head 30 or scale 33,
Scale line (engraved) 34 as shown in Figure 4
Since the amount of reflected light changes when passing through the position, the ratio of (amount of emitted light) to (amount of received light) changes. This change appears as a raw output waveform, but since this waveform is unstable or has two or more peaks and lacks reliability, this change in light amount is converted into an electrical signal and a binary signal is generated. It is preferable to output it as . The binarized signal can be transmitted as a TTL signal (digital) to a counter circuit, and the number of graduations on the scale can be integrated and converted into the amount of movement.

In addition, in FIG. 4, 35 is the cognition level.

As shown in FIG. 3, two light receiving sections 32A and 32B are provided with a phase delay, and a fourth light receiving section 32 is provided in order to determine the moving direction of the scale.
As shown in the figure, by setting the two light receiving sections 32A and 32B at a certain angle θ with respect to the scale line 34 of the scale 33, the A-phase and B-phase signals with delayed phases are output simultaneously. . By using this binary signal with a phase difference, the counter is raised and lowered in the moving direction of the scale. That is, when the A-phase pulse is input before the B-phase pulse, it is a positive value, and when the opposite is the case, it is a negative value.

It is sufficient to generate a phase difference of about 90 degrees to determine the direction of movement, and for this purpose, as shown in FIG. It is preferable to set it by shaking it by =4.8 degrees. As a result, the raw output waveforms of the A phase and B phase become as shown in the middle part of FIG. 4. In this case, if approximately half the height of the raw output waveform is set as the threshold level 35, the binarized waveform (digitized waveform) shown in the lower part of the figure is obtained.

Next, an explanation will be given based on the block circuit diagram shown in FIG. 5. The left side of the dotted line in the figure is the sensor head section 3
0, and the control section 60 is on the right side. 36 is, for example, a high-brightness red light emitting diode used in the light projecting section 31, and 37A and 37B are light receiving elements (for example, PIN diodes, etc.) used in the light receiving section 32. It is preferable that the light receiving circuit be the same circuit for both A phase and B phase, and the obtained raw output waveform should be 400 to 500
The signal is amplified by an amplifier 38 approximately twice as much. This is the sensor head section 30.

This amplified waveform signal is then transmitted to cable 40
is input to the discrimination value level adjustment section 39 via 2.
Make it into a value waveform.

The binary waveform signal is input as a TTL level signal to the up-down counter with built-in double circuit.
Displays the number of scale divisions. Also, this value is
Externally output as BCD output.

The BCD output is sent to a computer and used as data for automatic control management.

As a result of making a prototype of this device and conducting experiments, it was found that it is most effective to install the sensor head section 30 at a height of 1 mm from the surface of the scale 33;
300μm wide black stamp 34 (commercially available stainless steel)
The 1 mm scale markings on the surface of the scale could be detected well. Pitch resolution can be read by 0.5mm from 1mm using a normal up-down counter, but if the up-down counter has a built-in doubling circuit, it is possible to read by resolving 1mm to 0.25mm.

In the above embodiments, the scale 33 having the markings 34 was used to detect strokes by utilizing the fact that the amount of reflected light changed depending on the presence or absence of the markings.
It is also possible to provide a slit or the like in the slit and utilize the change in the amount of reflected light depending on the presence or absence of the slit. In this case, the discrimination is sharper than in the former case, which is preferable.

Next, the software of the microcomputer employed in the present invention will be outlined based on FIG.

(i) Input of tension management information There are two management methods: P-δ management and μ management, and in this embodiment, P-δ management will be explained.

First, input the control limit line. The outline of this limit line will be explained based on FIG. 7. In the figure, G ₁ and G ₂ are control limit lines. P ₁ is the retaining load.

The value of the tension control limit is determined for each group comprising a plurality of tension materials. The tension management limit value for the group that gets nervous for the first time is determined by theoretical calculations taking into account the empirical values, but for the group that gets nervous for the second time onwards,
New tension control limits are often determined by calculating the standard deviation from the previous tension results. If the work of determining this new tension control limit value is done manually, it will take time and it will not be possible to proceed to the next tension work. In the present invention, the microcomputer automatically performs this work, so it can be done in a short time.

(ii) Introducing tension force (detection of prestress amount and elongation) Measure the value of pressure transducer 9 with measuring device 7,
Also, the BCD from the stroke detection device 11
Transmit the output to PC 1.

(iii) CRT screen display or XYRec embossing display Control limit line G ₁ on the control graph screen in advance,
G ₂ is displayed.

Increase in tension (usually an increase in unit tension)
Plot the load P and elongation δ at each time.

Next, after removing the initial slip amount from the transmitted data, the origin of the measured load and elongation is corrected using the least squares method, and the P-δ curve (see Figure 7) is displayed on the control graph. .

(iv) If the measured value is within the control value, issue an order to increase the load. Display management graphs on the screen for monitoring.

1 to determine whether the control value is exceeded or not.
This may be done using only one plot, or the judgment may be made by referring to the previous and subsequent plots.

(v) When the predetermined load is reached, compare it again with the control value and settle within the control value (issue a drop-off command) and complete. If the control value is exceeded, an error is displayed and an emergency stop is performed, the current load is held (without issuing a lock-off command) and the next manual command is waited for.

(vi) Record and save the tension management graph on a floppy disk, etc. This data can be output even after stressful work.

One task is completed using the above software, and the next step is the process of introducing tension force. In addition to the above software, there is also an emergency interrupt function during automatic computer control,
Refill function for repeated tension, output function for control limit update data, creation output and recording function of tension control chart, automatic measurement during manual tension, display of measured values, display of comparison with control values, measured values You may also add records, etc.

Note that it is preferable to create the above software program using Basic, etc., and then ROM-pack it and install it into a personal computer.

Although one embodiment of the present invention has been described above, the present invention is not limited thereto, and the following embodiments may be adopted.

That is, as shown in FIG. 8, microcomputer equipment may be installed in the oil supply/discharge pipes 2 and 3.

In the same figure, reference numeral 13 is a microcomputer device for the automatic tension/automatic management system. device, etc.), a solenoid valve drive device, and a measuring instrument, and also includes a pressure transducer 9 and a solenoid valve 10.

14 is the hydraulic pump circuit board, 15 is the 200V power supply,
16 is a 100V power supply. In addition, in the same figure, the first
Parts with the same symbols as those shown in the figure have the same names,
Since these members or parts have the same function, their explanation will be omitted.

The board computer used in this embodiment has a function as a terminal of a host computer. This allows the host computer to control multiple board computers (while keeping timing).
It is effective when simultaneous tension is required, such as double tension.

That is, when performing interlocking tensioning such as double-pulling tensioning, the timing can be automatically determined by an ostocomputer that centrally controls each microcomputer, so it is easy to introduce a constant tensioning force.

The control method of the present invention is based on the ``Reinforcement method for sloughs around columns and openings in prestressed flat plate structure'' (patent application published in 1999), which was previously proposed by the applicant.
61-117526).

[Effect of the invention] According to the present invention, there are the following effects.

(1) A microcomputer can be brought to the site to fully automate everything from the introduction of tension to its management, resulting in low costs and no need for specialized engineers.
This saves labor costs, reduces stressful work time, and allows for safer work.

(2) It is also possible to introduce a certain amount of tension, ensuring quality.

(3) Conventionally, tension control charts and control tables must be submitted to the administrator without delay, but because they are done manually, they may be submitted only after all tension work has been completed. Therefore, even if inappropriate tension points are discovered at that time, it may be too late. On the other hand,
In the present invention, the above problem can be solved because the microcomputer automatically performs the process.

(4) Further, according to the present invention, the device is small, lightweight, difficult to break, convenient to handle, and can measure stroke movement with necessary and sufficient accuracy.

(5) In particular, according to the present invention, since the actual amount of movement is detected by using the light receiving section to detect the number of passages of the scale graduations of the scale line, the amount of movement of the stroke is detected. This has the advantage that relatively inexpensive components such as the light receiving section, the light receiving section, and the computer equipment can be used.

(6) Furthermore, since it has a configuration in which two light receiving sections are provided with a phase lag, it has the effect that not only the amount of movement of the stroke but also the direction of movement can be detected.

The application field of this device is, for example, the displacement of the header of a machine tool, which conventionally uses a potentiometer displacement type (maximum extended length: twice the amount of header movement + extra length). can be changed to this device. At this time, it is only necessary to attach a scale corresponding to the amount of movement of the header at a predetermined position, which has the advantage of simplifying the machine tool. Furthermore, the scale may be engraved according to the required accuracy. However, since it has the ability to be resolved down to 1/4 mm with a 1 mm scale, it is only necessary to set the scale at four times the required minimum scale, which simplifies scale production. Furthermore, when fine precision is required, this can be achieved by making the scale graduations finer and changing the fiber diameters of the light emitting and receiving sections.

[Brief explanation of drawings]

Fig. 1 is a schematic explanatory diagram showing an example of a device for carrying out the control method of the present invention, Fig. 2 is a front view showing a case in which the above device is integrated into a unit, and Fig. 3 is a diagram showing the tip of the sensor head section. Side view showing an example, No. 4
The figure is an explanatory diagram showing the raw output waveform and the binarized waveform when the light emitter and light receiver are appropriately arranged with respect to the scale line, Figure 5 is a circuit diagram of a device preferably used in the present invention, and Figure 6 7 is a flowchart of software used in the present invention, FIG. 7 is a P-δ diagram for tension management employed in the present invention, and FIG. 8 is a schematic explanatory diagram showing another example of the present invention. 1: Hydraulic jack, 2: Oil supply pipe, 3: Oil discharge pipe, 4: Hydraulic pump, 5: Computer, 6: Control system, 7: Measuring equipment, 8: Data insertion part, 9: Pressure transducer, 10: Solenoid valve, 11: Stroke detection device, 12: Control cable, 13:
Automatic tension/automatic management system equipment group, 14: Hydraulic pump circuit board, 15: 200V power supply, 16: 100V
Power supply, 30: Sensor head section, 31: Light projecting section,
32: Light receiving part, 33: Scale, 34: Scale line or marking, 35: Discrimination level.

Claims (1)

[Claims] 1 A hydraulic jack is set on the prestressed steel material placed at a predetermined position, and when applying hydraulic pressure to the prestressed steel material by supplying hydraulic pressure from the hydraulic system to the hydraulic jack, a microcomputer device is installed at the tension site. Then, the tension management information including at least the control limit value is input into the microcomputer device, and then the automatically measured tension data and the measured data of the stroke movement of the hydraulic jack are introduced, and the control limit value and the above control limit value are input. In an automatic control device that controls tension by making a comparative judgment and transmitting a tension control signal to the hydraulic system, a scale formed along the direction of movement of the stroke of the hydraulic jack and capable of measuring the amount of movement of the stroke. A part to be measured having a line, a light projecting part that shines light onto the part to be measured, and a light projecting part set in a straight line at both ends of the light projecting part at a slight predetermined angle with respect to the scale line, and reflecting light of the light. and a sensor head consisting of two light receiving sections that receive light, and a stroke detection device that detects the amount of movement of the stroke according to a change in the amount of light received when passing through the scale graduations of the scale line. Features an automatic control device for tension jacks for prestressed construction.