JPH0428708Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a welding machine used for resistance welding.
In particular, the present invention relates to a portable welding machine that is small, lightweight, and suitable for carrying.

[Conventional technology]

FIG. 4 shows a conventional example of an air conditioner in which a heat insulating material 32 is attached to a cylindrical air conditioning duct 31 made of a conductive material by resistance welding. is inserted, and a ground 35 is attached to the air conditioning duct 31. Then, due to Joule heat generated by the current flowing from the electrode 36 to the pin 33, the pin 3
3 and the air conditioning duct 31 is heated, and at the same time, due to the pressure P applied to the pin 33, the pin 33 and the air conditioning duct 31 remain in close contact with each other, and after the current stops, they solidify as one piece, and as a result, the pin 33 is connected to the air conditioning duct 31. It is welded to the duct 31.

[Problem that the invention attempts to solve]

However, in the above-mentioned prior art, the current flowing through each pin 33 varies depending on the distance from each pin 33 to the earth point 35a, resulting in a problem that welding unevenness occurs. In addition, in order to eliminate such welding unevenness, it is necessary to pass a large current through the electrodes, which makes the transformer large and heavy. Therefore, the transformer and the electrode 36 are built into the same housing and used as a portable welding machine. The problem was that it was not realistically possible to do so.

An object of the present invention is to provide a portable welding machine that can quickly perform homogeneous welding without passing a large current through the electrodes.

[Means for solving problems]

In order to achieve such an objective, the portable welding machine according to the present invention is a portable welding machine for welding a metal pin for fixing a heat insulating material wrapped around the outer circumference of a cylindrical metal air conditioning duct to the air conditioning duct. The air conditioning duct is composed of a metal plate whose outer peripheral surface is coated with a vinyl chloride sheet, and the metal pin is composed of a shaft portion and a flange portion, and the shaft portion has a sharp tip,
The portable welding machine has a pair of positive and negative electrodes that are biased to press against the flange of the metal pin so as to be able to slide, and are arranged in parallel at a constant interval, and a current is applied to the electrodes. It is equipped with a transformer for transmitting data and an inverter circuit section for controlling the transformer, and the electrodes, the transformer, and the inverter circuit section are housed in a housing having a gripping section.

[Effect]

According to the above-mentioned configuration, all of the electrical appliances such as the transformer, which is the main component of the resistance welding circuit, and the printed circuit board that constitutes the inverter circuit are housed in the housing, and the positive and negative pairs arranged in parallel from the welding circuit are A current is supplied to the electrodes. Since the distance between the electrodes is set constant and small, a constant current always flows through the welding part, eliminating uneven welding and reducing the current sent from the transformer to the pair of electrodes. Furthermore, the number of turns of the transformer coil can be reduced for a desired current value by the high frequency sent from the inverter circuit, so the transformer can be made smaller and lighter. In this way, by pressing and energizing two metal pins with sharp tips through the insulation material on the outer lining of the air conditioning duct with a pair of electrodes of this welding machine, the pins can be easily attached to the outer surface of the PVC-coated metal plate duct. Can be welded.

〔Example〕

Hereinafter, the present invention will be explained based on embodiments shown in the drawings.

The portable welding machine 1 includes a housing 2, a pair of positive and negative electrodes 3 and 4, a transformer 5, and an inverter circuit section 6. The housing 2 is a body part 2a
and a grip portion 2b extending vertically from the middle portion of the body portion 2a.

The electrodes 3 and 4 are slidably arranged in parallel at a distance C from a guide bush 8 made of a cylindrical insulating material fixed to the opening at the tip of the body 2a of the housing 2. protrudes outward. Flanged guide pins 10A and 10B are screwed onto the base ends of the electrodes 3 and 4, respectively, with one terminal 9a of the cables 9A and 9B interposed therebetween. The guide pins 10A and 10B are loosely fitted into two recesses 11a formed in a fixing member 11 fixed to the housing 2. Guide pin 10A, 1
A compression spring 12 is installed between the flange portion 10a of 0B and the bottom surface of the recess 11a, respectively.
The guide pins 10A and 10B, that is, the electrodes 3 and 4, are urged in the direction of arrow A by the compression spring 12.

The transformer 5 is fixed to the middle part of the body 2a of the housing 2, and the other terminals 9b of the cables 9A, 9B are fixed to the distal ends thereof, thereby connecting the transformer 5 to the electrodes 3, 4. The inverter circuit section 6 is connected to the power supply section 13, and has two transistors 15A and 15 for sending high frequency to the transformer 5.
B, and a printed circuit board 16 that controls the transistors 15A and 15B. The transistors 15A and 15B are arranged adjacent to the transformer 5 on the opposite side of the body 2a of the housing 2 from the electrodes 3 and 4. The printed circuit board 16 is arranged in the grip part 2b of the housing 2, and the printed circuit board 1
6, the high frequency of the inverter circuit section 6 is 400~
Converted to 1000Hz.

In addition, in Fig. 2, 17 is the bass amplifier, 18
19 is a pulse oscillator, 19 is an energization time setting device, and 20 is a start switch.

Next, the operation of the embodiment of the present invention will be explained.

3, similar to that shown in FIG. 4, a heat insulating material 22 is attached to an air conditioning duct 21 made of a cylindrical conductive material such as a galvanized iron plate in an air conditioner using the portable welding machine 1 according to the present invention. FIG.

The outer peripheral surface of the air conditioning duct 21 is coated with an insulating material sheet, for example, a vinyl chloride sheet 23. When attaching the heat insulating material 22 to the air conditioning duct 21, first attach the two flanged pins 25.
A, 25B with heat insulating material 2 at the same spacing as electrodes 3, 4.
Insert into 2. The pins 25A and 25B are made of metal and consist of a shaft portion 25a and a flange portion 25b.
The tip of 5a is formed into a sharp shape, and the length is set to be slightly smaller than the thickness of the heat insulating material 22.

Next, the electrodes 3 and 4 are pressed against the flange portions 25b of the pins 25A and 25B, and the welding machine 1 is energized.
Then, the vinyl chloride sheet 23 coated on the air conditioning duct 21 is broken by the pressure of the compression spring 12 acting on the tips of the pins 25A, 25B, and the tips of the pins 25A, 25B are attached to the air conditioning duct 2.
directly contacts the outer peripheral surface of 1. Then, the current from the transformer 5 flows in the direction of arrow B to pins 25A and 25.
Due to the Joule heat generated in the contact area between B and the air conditioning duct 21, the contact area is heated and melted, and the pressure of the compression spring 12 applied to the pins 25A, 25B causes the tips of the pins 25A, 25B and the air conditioning duct 2 to
While remaining in close contact with the outer circumferential surface of No. 1, the welding is completed by solidifying after the current supply is stopped. In this case, the high frequency signal sent to the transformer 5 is, for example, 400
Hz, and as a result, the current value sent from the transformer 15 to the electrodes 3 and 4 is about 2000 amperes.

By sequentially welding the pins 25A and 25B inserted into the other parts of the heat insulating material 22 to the outer peripheral surface of the air conditioning duct 21, the heat insulating material 22 can be reliably attached to the air conditioning duct 21.
The current flowing between the pins 25A and 25B is always constant over the entire area, so welding performance is constant over the entire joint between the pins 25A and 25B and the air conditioning duct 21 without causing welding unevenness. In addition, this makes it possible to reduce the current value sent from the transformer 5 to the electrodes 3 and 4, and also to increase the frequency sent to the transformer 5 by the inverter circuit 6, reducing the number of turns of the coil of the transformer 5. Therefore, the transformer 5 can be made small and lightweight.

[Effect of idea]

As described above, according to the present invention, welding is performed by sending current to the electrodes arranged in parallel at regular intervals, so the current flowing between the electrodes is constant and no welding unevenness occurs. Furthermore, since the transformer is small and lightweight and can be housed together with the electrodes, the welding machine can be moved freely to any location, improving workability. Furthermore, by using a metal pin with a sharp tip, it is possible to improve the efficiency and safety of the installation work of the outer heat insulating material of a metal air conditioning duct coated with PVC.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of a portable welding machine according to the present invention, Fig. 2 is a circuit diagram of what is shown in Fig. 1, Fig. 3 is an explanatory diagram showing an example of the use of the portable welding machine, and Fig. 4 is It is an explanatory view showing one example of use of resistance welding concerning a conventional example. 1...Portable welding machine, 3, 4...Electrode, 5...
Transformer, 6...Inverter circuit section.

Claims (1)

[Scope of Claim for Utility Model Registration] A portable welding machine for welding a metal pin for fixing a heat insulating material wrapped around the outer circumference of a cylindrical metal air conditioning duct to the air conditioning duct, wherein the air conditioning duct has an outer circumferential surface made of vinyl chloride. The metal pin is composed of a sheet-coated metal plate, and the metal pin is composed of a shaft portion and a flange portion, and has a sharp tip end, and the portable welding machine presses the flange portion of the metal pin. A pair of positive and negative electrodes that are biased to be slidable and arranged in parallel at a constant interval, a transformer for sending current to the electrodes, and an inverter circuit for controlling the transformer. What is claimed is: 1. A portable welding machine comprising: a housing having a gripping portion;