JPS6115797B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for simultaneously automatically gas pressure welding a plurality of joints such as reinforcing bars.

The gas pressure welding method is widely used for on-site work on reinforcing bars and rails because it can produce joints with high joint strength using simple equipment. There is also a method in which the pressure welding process is divided into a plurality of steps and these steps are sequentially executed by sequence control to automatically perform the work.

FIG. 1 is a diagram showing an example of the process of automatic gas pressure welding of reinforcing bars, and the pressure welding process consists of eight steps. The heating process is divided into steps 1 to 2, in which the joint is heated by a reducing flame, and steps 3 to 6, in which the joint is heated by a neutral flame. In addition, the burner that heats the joint is reciprocated along the reinforcing steel,
As the pressure welding process progresses, the amplitude changes from A (step 3, e.g. 5 mm) to B (step 4, e.g. 25 mm).
mm) and C (steps 5 and 6, for example 45 mm).

The pressurizing process begins in step 2 by driving a hydraulic pump to pressurize a hydraulic cylinder that applies pressing force to the joint, and in step 2, the reinforcing bars that have been preliminarily heated are pressed to bring the end faces into close contact. In steps 3, 4, and 5, the check valve and hydraulic switching valve installed between the hydraulic pump and the hydraulic cylinder are closed, so even after the hydraulic pump is stopped, the inside of the hydraulic cylinder remains pressurized. ing. However, at these stages, when the joint is compressed, the hydraulic pump is not driven and the oil pressure in the hydraulic cylinder drops, so that the compressive deformation of the joint is slight. In step 6, the hydraulic pump is driven again to apply pressing force to the joint heated to the welding temperature. At this stage, the joint is subjected to maximum compression and gradually deforms and swells into a knob, and the reinforcing bars are welded together. In step 8, the hydraulic switching valve is opened, the hydraulic pressure in the hydraulic cylinder is released, the pressing force is set to 0, and the pressing process is completed.

By the way, recently, in order to improve the efficiency of reinforcing bar assembly work, several reinforcing bars are assembled in advance into blocks lined up at the required intervals using spacers, etc. A construction method that butts and joins blocks onto other reinforcing bars (saki-assumi construction method) has come to be adopted. In this case, if the individual reinforcing bars in a block are welded one after another, the lengths of the reinforcing bars in the block will not only differ before and after welding due to shrinkage of the reinforcing bars due to welding, but will also be uneven after welding, so the reinforcing bars This may cause the blocks to tilt relative to each other, or the reinforcing bars may not be able to be pulled together, making pressure welding impossible.

Therefore, in order to perform pressure welding of such pre-assembled reinforcing bars, it is desirable to join the reinforcing bars constituting the block at the same time. In such simultaneous pressure welding of reinforcing bars, it is necessary that there be no large difference in compression speed between each pair of reinforcing bars. If the compression speed difference is large, the block assembly may come off.

However, in the conventional automatic pressure welding method described above, it is difficult to arbitrarily control the compression speed, so when pressing multiple reinforcing bars at the same time, if for some reason there is a difference in the heating temperature of each pair of reinforcing bars, It is also difficult to control when there is a large difference in compression speed.

This invention was made in order to solve the above-mentioned problems in simultaneous automatic gas pressure welding of multiple joints. It is an object of the present invention to provide a simultaneous automatic gas pressure welding method for multiple joints, which can reliably perform pressure welding work without causing interruptions in pressure welding.

In this invention, the process of pressurizing the joint whose joint portion has reached the pressure welding temperature is divided in advance into a plurality of pressurizing stages, and a reference compression amount is determined for each pressurizing stage. Then, at each pressurization stage, the joints whose compression amount reaches the standard compression amount stop pressurizing, and when the compression amount of all the joints reaches the standard compression amount, pressurization of each joint simultaneously. resume. In this way, the pressurization is successively progressed until all the joints of the joints are compressed to the required total compression amount.

The start and stop of pressurization at each pressurization stage is automatic. Further, a potentiometer or the like is used to detect the amount of compression.

In this invention, the pressurization process is divided into multiple stages,
The amount of compression of the joint joint is made to be the same at each stage. That is, each joint is pressed together at approximately the same average compression speed. Therefore, there is no possibility that the amount of compression of some of the joints may be too large or too small, causing the joints to tilt relative to each other, or for the joints to come apart, resulting in interruption of the pressure welding operation.

This invention will be explained in more detail below.

FIG. 2 shows an example of an automatic gas pressure welding device for carrying out the method of the present invention, and the pressure welding device mainly includes a heating device 11, a pressurizing device 21, and a control device 41.
It is composed of. Although only one set of this pressure welding device is shown in the figure, in order to simultaneously pressure weld a plurality of joints, a heating device 11 and a pressure device 2 are used.
A plurality of sets consisting of 1 and 1 are provided.

The heating device 11 includes a burner 14 to which an acetylene gas supply pipe 12 and an oxygen supply pipe 13 are connected, and a burner drive device 17. The burner 14 has an annular main body 15 that surrounds the materials 1 and 2 to be joined (hereinafter described as reinforcing bars), and a large number of nozzles 16 are provided in the main body 15 along the circumferential direction. The burner 14 is supported by a support portion 18 of a burner drive device 17 so as to be swingable around the reinforcing bars 1 and 2 to be pressed and to be able to reciprocate along the reinforcing bars 1 and 2. The swinging of the burner 14 includes a motor 19, and a swinging mechanism using an eccentric cam etc., and the reciprocating motion includes a servo motor 20.
This is achieved by a reciprocating mechanism using a ball screw or the like. The driving of these motors 19 and 20 is controlled by signals from a control device 41, respectively.

The pressurizing device 21 consists of a reinforcing bar supporter 22 and a pressurizing source 30. The reinforcing bar supporter 22 has a cylindrical main body 23, and the main body 23 has a fixed chuck 24.
It is attached to the reinforcing bars 1 that have already been joined or fixed. A sliding block 25 having a movable chuck 26 is inserted into the main body 23 so as to be movable back and forth. A ram 28 of a hydraulic cylinder 27 is connected to the sliding block 25, and a moving chuck 26 grips the other reinforcing bar 2. In addition, the main body 23
A direct-acting potentiometer 29 for detecting the displacement of the sliding block 25 is attached to.

The pressurization source 30 includes a pump 32 driven by a motor 31, and pressure oil from the pump 32 is supplied to the hydraulic cylinder 27 from a hose 34 via a check valve 33. A relief valve 35 and an electromagnetic switching valve 36 are attached to a line branching from the middle of the hose 34. The operation of motor 31 and switching valve 36 is controlled by signals from control device 41.

The control device 41 includes a microcomputer, a setting device, etc., inputs an offset amount signal from the potentiometer 29, and controls the motors 19, 20,
31, outputs an operation signal to the switching valve 36 and oxygen and acetylene gas supply sources (not shown).

Next, a method of automatically gas pressure welding a reinforcing bar block by the method of the present invention using the pressure welding apparatus configured as described above will be explained.

As shown in FIG. 3, the reinforcing bars 1 that have already been fixed to the concrete foundation 5 and the reinforcing bars 2 to be joined are butted against each other, the former is gripped by the fixing chuck 24 and the reinforcing bar support 22 is fixed, and the latter is grabbed by the moving chuck 26. Grab it.

The press-welding process proceeds according to the steps shown in FIG. 1 described above. Then, in step 6, each reinforcing bar pair a to d is pressurized in stages. FIG. 4 is a graph showing the relationship between pressurization time t and compression amount δ, where t _T represents the total pressurization time in step 6, and δ _T represents the required total compression amount. The total compression amount δ _T is divided into reference compression amounts δ ₁ , δ _{2 .} . . for each pressurization stage. For example, when the total compression amount δ _T is 24 mm, pressurization is divided into 8 stages, and when compressing at a constant speed, the standard compression amount for each stage is 3 mm.

As shown in the graph of FIG. 4, in the first pressurization stage, reinforcing bar pair a first reaches the standard compression amount δ ₁ , and then reinforcing bar pairs b to d reach the standard compression amount δ ₁ . The reason why all reinforcing bar pairs a to d do not reach the standard compression amount δ ₁ at the same time is mainly because there are differences in the time required to reach step 5 and the heating gas flow rate, and as a result, there are variations in the heating temperature of the joints. It is. The amount of compression of each reinforcing bar pair a to d is detected by a potentiometer 29 and inputted to a control device 41 . For the pair of reinforcing bars that have reached the reference compression amount δ ₁ , the driving of the hydraulic pump 32 is stopped by a signal from the control device 41, and the compression is interrupted. Then, when all reinforcing bar pairs a to d reach the standard compression amount δ ₁ (time t ₁ ), the hydraulic pump 32 of all reinforcing bar pairs
Start driving at the same time and start compression. In this way, the pressurization is progressed until the required total compression amount _δT is reached, and the pressure welding is completed.

The total amount of compression has an appropriate value depending on the dimensions of the reinforcing bars, the heating width (temperature distribution) of the joint, the shape and dimensions of the joint, and the compression speed also depends on the capacity of the pressurizer, cracks and bending of the joint. , determined experimentally in consideration of work efficiency, etc.

[Brief explanation of the drawing]

Figure 1 is a diagram showing an example of an automatic gas pressure welding process;
Fig. 2 is a schematic diagram showing an example of an automatic gas pressure welding device that implements the method of the present invention, Fig. 3 is a schematic diagram showing the reinforcing bar support of the gas pressure welding device set in a reinforcing bar block, and Fig. 4 is a schematic diagram of this example. This is a graph illustrating the method of the invention and showing the relationship between pressurization time and compression amount. 1, 2...Reinforcing bar, 11...Heating device, 14...
Burner, 17...Burner drive device, 19,2
0, 31... Motor, 21... Pressure device, 22
...Reinforcing bar supporter, 24, 26...Chick, 25
...Sliding block, 27 ...Hydraulic cylinder, 2
9... Potentiometer, 30... Pressure source, 3
2...Hydraulic pump, 35...Relief valve, 36...
...Solenoid switching valve, 41...control device.

Claims (1)

[Claims] 1. In a method of simultaneously gas pressure welding multiple joints by automatically progressing the work consisting of multiple steps in stages, the process of pressurizing the joints whose joints have reached the welding temperature is divided in advance into multiple pressurization stages, A standard compression amount is determined for each pressurization stage, and when the compression amount of the joint reaches the standard compression amount, the joint stops applying pressure, and when the compression amount of all the joints reaches the standard compression amount, simultaneously A simultaneous automatic gas pressure welding method for multiple joints, characterized by restarting pressurization of each joint and moving to the next pressurization stage.