JPS628945Y2 - - Google Patents

Description

[Detailed explanation of the invention] (a) Industrial application field The present invention relates to a portable spot gun. This invention relates to a means for preventing diversion.

(b) Prior Art It is well known that portable spot guns are used as welding equipment in automobile body assembly lines and the like. A conventional portable spot gun clamps a workpiece between electrodes installed at the tip of the arm, and uses current supplied between the electrodes to instantaneously heat the clamped part of the workpiece to the melting temperature to create a desired welded area on the workpiece. However, since it is manually operated, the workpiece and the arm of the spot gun come into contact with each other during the welding operation, resulting in the inconvenience of creating a shunt at the contact area.

If such a shunt occurs, quality defects such as burnt spots, holes, or reduced spot strength will occur on the workpiece, so workers must be careful not to touch the workpiece with the arm of the spot gun while welding. carry out the work; For this reason, the workability of the welding process is reduced, which naturally has an adverse effect on the reduction in manufacturing costs.

As a means to avoid the above-mentioned problems, there have been methods of adjusting the shape of the arm of the spot gun and the gripping angle with respect to the workpiece according to the shape of the workpiece, and methods of applying an insulating layer, such as a layer wrapped with duct tape, to the outer peripheral surface of the arm. Methods such as forming the arm or applying ceramic coating to the arm have been adopted, but each method has practical difficulties, and no fundamental solution to the above problem has been found. That is, the first method is not economical because it requires preparing a large number of spot guns to accommodate changes in the shape and dimensions of the workpiece.
Furthermore, depending on the size or shape of the workpieces to be welded, the angle at which the arm holds the workpieces must be set at an angle that is not favorable for operation, which naturally greatly impedes the workability of the welding process. . On the other hand, the second method leaves problems in the shunt prevention performance and service life due to the fact that the insulation and abrasion resistance of the packing tape are not necessarily maintained at a practically satisfactory level. ing. In addition, while the third method has good shunt prevention performance,
Ceramic coating costs are high, so it is difficult to say that it is an advantageous method from the perspective of capital investment.

In order to overcome the drawbacks of the conventional techniques, the present inventors proposed a method of applying a single layer of epoxy resin to the arm of a spot gun, or an insulation method of mixing glass fibers into liquid epoxy resin as a means of improving durability. Attempts have been made to apply resin to the arm of a spot gun and then cure it to form an insulating film, but none of these methods yielded satisfactory results. In other words, when only liquid epoxy resin is applied to a single layer structure, it is brittle and the resin coating easily breaks due to collision between the arm and the workpiece during welding work.On the other hand, when the resin layer is thick, the arm This increases the thickness and impairs the operability of the arm during welding work.

The inventors of the present invention continued their intensive research to find a practical means to solve the above-mentioned problems and arrived at the present invention.

(c) Purpose of the invention The main purpose of the invention is to provide a portable spot gun with good shunt prevention performance and operability.

Another main object of the present invention is to find a multi-layer insulation structure for a portable spot gun that has excellent insulation properties and durability.

(d) Structure of the invention The present invention is a portable device in which a multiple insulating layer consisting of a first insulating resin coating layer, an insulating tape winding layer, and a second insulating resin coating layer is formed on the circumferential surface of an electrode fixing arm. The main topic is spot guns.

(E) Example: A liquid epoxy resin containing an appropriate amount of hardener was applied to the electrode fixing arm 1 of the portable spot gun.
After brushing to a thickness of 0.5 mm to form a first insulating resin coating layer 12, glass fiber tape 3 to reinforce the resin was wound, and the liquid epoxy resin was brushed to a thickness of about 0.5 mm so as to cover the entire surface of the insulating tape wound layer to form a second insulating resin coating layer 4. The portable spot gun thus formed a multiple insulating layer on the peripheral surface of the electrode fixing arm, and the liquid epoxy resin was then cured for about 20 hours in the usual manner to obtain an electrode fixing arm in which the epoxy resin forming the first and second insulating resin coating layers had permeated between the glass fibers.

(f) Effects of the invention The portable spot gun according to the invention has a unique multi-insulation structure in which the first and second insulating resin coating layers are firmly bonded via the insulating tape winding layer. Although the thickness of the resin film is thinner than that of the insulating means described above, durability and insulation can be maintained at an extremely good level. Further, according to the present invention, the thickness of the insulating layer can be adjusted as necessary, and by reducing the thickness, the operability of the spot gun during welding work can be improved. In addition, when comparing the present invention and conventional technology from the viewpoint of economic efficiency, approximately 90%
It is possible to reduce the insulation processing cost by about %. Therefore, the present invention not only improves the operability of the spot gun during welding work or the ability to prevent flow separation between the spot gun and the workpiece, but also greatly contributes to improving the economic efficiency of the welding process. be.

[Brief explanation of the drawing]

FIG. 1 is a front view illustrating multiple insulating layers formed on the circumferential surface of an electrode fixing arm of a portable spot gun according to the present invention, and FIG. 2 is a perspective sectional view of the main part of the multiple insulating layers. DESCRIPTION OF SYMBOLS 1... Electrode fixing arm, 2... First insulating resin coating layer, 3... Insulating tape winding layer, 4... Second insulating resin coating layer.

Claims (1)

[Scope of utility model registration request] A portable spot gun characterized in that an electrode fixing arm is formed with multiple insulating layers consisting of a first insulating resin layer, an insulating tape winding layer, and a second insulating resin layer.