JPH0442118B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a self-propelled resistance seam welding machine,
In particular, the present invention relates to an improvement in a seam welding machine that forms the exterior of a building, such as the roof, by welding metal covering plates such as thin steel plates at multiple locations.

[Conventional technology]

In recent years, special large structures made of thin plates have been developed, and self-propelled seam welding machines have been used to enable the application of resistance seam welding machines to such large structures.

Fig. 4 shows a part of the joint part of the metal covering plate 10 used for the roofing material of a building, (A)
1 shows the external appearance of the metal covering plate 10, and (B) shows a cross section in the FF direction of (A) viewed from above. In the figure, 10 is a metal covering plate of a member to be welded, 12
is a roof member of the structure; 14 is a hanger for joining the roof member 12 and the metal covering plate 10;
It is fixed to the roof member with screws and welded to the inside of the metal covering plate 10 by seam welding. Note that although part K in (A) shows the internal structure of the insertion part of the hanger 14, it cannot actually be observed from the outside. 16 is a seam welding position, and 18 is a portion where the plate thickness changes due to insertion of a hanger.

In this state, the metal covering plate 10 on the outside of the roof of the structure is seam welded. but,
When such a welding workpiece is welded using a conventional self-propelled seam welding machine, the above-mentioned hanger 1
It is not possible to satisfactorily weld the portions 18 where the plate pressure changes, which occur before and after the intersection of the 4 arrangement portion and the cross-fold (not shown), resulting in unwelded portions. Therefore, there was a problem in terms of watertightness, which is the most important aspect of a roofing member.

Therefore, currently, in one run, after welding has been completed, the unwelded parts can be repaired by spot welding, the same welding machine can be run in reverse to weld the unwelded parts again, and other types of lifting One method is to change the shape of the child itself.

[Problem that the invention seeks to solve]

However, when welding is carried out using the various techniques mentioned above, a lot of work time is required.
In addition to interfering with FA, there was also the problem that accurate welding could not be performed.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a seam welding machine that can perform good seam welding and shorten the working time.

[Means for solving problems]

The seam welding machine according to the present invention includes a plate thickness detection means for detecting the plate thickness of a member to be welded; a control means for controlling welding conditions based on detection information of the plate thickness detection means; , detecting a portion where the plate thickness changes based on the information of the plate thickness detection means, and temporarily stopping the running of the seam welding machine and simultaneously increasing the welding current at the portion where the plate thickness changes, thereby solving the above problem. This solves the problem.

[Effect]

In this invention, the plate thickness changing portion is detected using the information obtained by the plate thickness detection means, and based on this, the running of the seam welding machine is temporarily stopped at the plate thickness changing portion, and at the same time, the welding current is stopped. Because of this, the welding can be performed in the same way as spot welding in areas where the plate thickness changes, and good welding can be performed with no unwelded parts in one run, simplifying the work process. That will happen.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an outline of the configuration of an embodiment of the present invention. In the figure, reference numeral 20 denotes a welding cart which can be moved forward and backward by running wheels (not shown) provided at the bottom and a motor (not shown) that drives the running wheels. 22a and 22b are rotatable electrode wheels press-welded to the metal cover plate 10, and the rotation axis of 22a is connected to the welding cart 20.
22b is configured to be movable in a direction perpendicular to the metal cover plate 10. 24 is a sensor for detecting plate thickness, and is connected to the electrode ring 22b by a support shaft 26. Also, sensor 2
A spring (not shown) is provided inside the electrode wheel 22b, and the plate pressure can be detected by measuring the compressive load on the spring caused by the fluctuation of the electrode wheel 22b.

Reference numeral 28 denotes a control section, which controls the current flowing through the electrode wheel 22b and the motor (not shown) for driving the welding cart 20 based on information from the sensor 24. The details of the construction of such a control section are shown in block diagram form in FIG. In the figure, a signal output from a sensor 24 is amplified by an amplifier 30, and a comparator 32 is configured to compare the signal with a threshold value 34 set in advance in the comparator 32. The threshold value 34 is data for detecting the plate thickness change portion 18, and is set at a position approximately midway between the thin plate thickness portion and the thick plate thickness portion. The information obtained by the comparator 32 is output to the timer 36 connected to the motor driver 38 and the SCR ignition circuit 40, respectively. Based on the information, the motor driver 38 controls the motor, and the SCR ignition circuit 40 controls the SCR. are controlled based on the setting time of the timer 36.

Next, we will discuss the overall operation of the above embodiment in the third section.
This will be explained with reference to the figures.

In FIG. 3, the relationship between the output of the sensor 24, the traveling speed of the welding cart 20, and the welding current with respect to the position of the metal covering plate 10 is represented by a time chart.

First, when welding work is started and the electrode wheels 22a and 22b are located at the reference point where the output of the sensor 24, that is, the thickness of the metal covering plate 10 is less than the threshold value, the output from the sensor 24 is only transmitted to the comparator 32. Welding is carried out using the normal standard running speed and welding current.

Next, the metal covering plate 1 is
0 increases, the comparator 32 determines the position where the output of the sensor 24 reaches the threshold value 34 as the plate thickness changing portion 18 based on the plate thickness sequentially detected by the sensor 24, and the motor driver 38 The motor is controlled via the SCR ignition circuit 40 to stop the traveling of the welding cart 20, and the SCR ignition circuit 40 is
is controlled to cause a large current to flow through the electrode wheels 22a and 22b.
Here, an appropriate time corresponding to the rate of change in plate thickness is set in advance in the timer 36, and the welding cart 20 is stopped running and the electrode wheels 22a, 22 are stopped for this time.
A large current is sent to 2b.

Next, when the set time mentioned above has elapsed, the timer 3
6 is released, the welding cart 20 is driven to run again,
Reduce the welding current slightly. At this time, welding cart 2
The running speed and welding current of 0 are given based on the information detected by the sensor 24 in accordance with the thickness of the metal covering plate 10.

Next, when the thickness of the metal covering plate 10 reaches the threshold value 34 again, the welding of the plate thickness changing portion 18 is performed in a stopped state by the same control as in the case described above, and then the thickness of the metal covering plate 10 is below the threshold value, that is, when the electrode wheels 22a, 22b pass through the reference location, welding is performed using the above-mentioned reference traveling speed and welding current.

In the above embodiment, welding is performed at a welding speed and welding current that correspond to the thickness of the metal covering plate 10, and at the plate thickness changing portion 18, traveling is temporarily stopped and welding is performed using a large current.
This means that spot welding is combined with seam welding in the plate thickness changing portion 18. Therefore, the plate thickness changing portion 18 can be welded well, and overall welding can be performed well in one run. In addition, the plate thickness can be detected at the electrode wheels 22a and 22b, and welding conditions can be controlled in real time, making it possible to perform accurate welding without time lag.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be modified in various ways to achieve similar effects.

〔Effect of the invention〕

As explained above, the present invention has a special effect in that a single run of the self-propelled seam welding machine can perform good welding without leaving any unwelded parts, thereby simplifying the work process.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
3 and 3 are explanatory diagrams showing the effects of the embodiment, and FIG.
The figures are a perspective view and a cross-sectional view showing problems with the prior art. "Explanation of symbols of main parts", 10...Metal coated plate, 18... Plate thickness changing part, 20... Welding trolley, 24
...Sensor, 28...Control unit. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A seam welding machine that performs welding work while self-propelled, comprising: a plate thickness detection means for detecting the plate thickness of a material to be welded; and control of welding conditions based on information detected by the plate thickness detection means. The control means detects a portion where the plate thickness changes based on the information from the plate thickness detection means, and temporarily stops the running of the seam welding machine in the portion where the plate thickness changes. A seam welding machine characterized by increasing welding current at the same time as stopping it.