JPH0450068B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Field of Application> The present invention relates to an air cap for a spray gun that injects paint or the like.

<Prior Art> As shown in Fig. 7, the air cap of this type of spray gun, which is commonly used in the past, is used to atomize the liquid ejected from the tip of the spray gun body, and to atomize the atomized liquid. The main purpose is to introduce compressed air to change the pattern. It plays an especially important role in air spray guns.

Until now, this air cap has been formed by casting, forging, cutting from a round bar, etc. For this reason, the weight is heavy, and if a hand gun is used as an air spray gun, the fatigue during painting work will be large, and painting workers are demanding a lighter weight. Also, in the case of an automatic gun, if the weight of the air cap is large, the inertia generated when swinging the automatic gun will also be large, which will add an impact force correspondingly, which will interfere with the smooth movement of the equipment. This can lead to poor finish on painted surfaces and equipment failure. Furthermore, in the case of air caps manufactured using conventional molds, the wall thickness cannot be made very thin due to processing and pressure resistance factors, and as a result, it is difficult to obtain a large internal volume of the air cap. Therefore, the flow was slow at the same amount of ejected air, and it was somewhat difficult to produce a soft paint mist. Also, if the air cap is made by cutting from a round bar,
The manufacturing process was also complicated and it was difficult to reduce the cost of the air cap for the spray gun.

<Problems to be solved by the invention> The present invention was made in view of the above-mentioned circumstances, and its objectives are, first, to reduce the weight;
The present invention provides an air cap for a spray gun that satisfies the following three points: secondly, the number of machining steps can be reduced, and thirdly, a soft paint mist can be obtained.

<Means for solving the problem> In the air cap of an external mixing spray gun, which ejects air for atomization from the center and air for pattern formation from the corners, each cylinder has a cylindrical shape made of thin plate material. The outer part has a through hole formed in the center, at least a pair of corner projections are formed at symmetrical positions around the through hole, and the inner part of the rear cylindrical part has a through hole formed in the center. A spigot part is formed on the periphery, a protrusion in which a center hole is formed is formed in the front center of the inner part, and a rear brim part bent forward is formed on the outer periphery of the rear cylindrical part. At least one hole for introducing compressed air supplied from the spray gun body is formed in the rear flange, and the through hole in the outer part and the protrusion in the inner part are connected to the outer part. The spigot part at the rear of the inner part and the rear brim part of the inner part are each airtightly connected.

<Example> Hereinafter, the present invention will be described in detail based on the drawings of the example.

In Figures 1 to 6, 1 is the outer part of the air cap, and the outer part 1 is formed from a thin plate through several stages of press working, and has a through hole 2 in its center. The corner protrusions 3, 3 are arranged vertically or horizontally symmetrically toward the front. Additionally, threaded portions 4 are provided at three locations on the rear outer periphery, which can be formed simultaneously during press working. Reference numeral 5 designates the inner part of the air cap, and the inner part 5 also has a protrusion 6 having a U-shaped cross section at the center of the front, which is formed by pressing a thin plate in several stages, and a spray gun is attached to the rear outer periphery of the air cap. Hole 7 for introducing compressed air supplied from the main body into the center hole or square hole
There are about six openings, and the rear collar 8 is formed so as to be bent forward and around the circumference.

Next, the protrusion 6 of the inner part 5 is press-fitted into the through hole 2 at the center of the outer part 1, and at the same time, the rear collar 8 of the inner part 5 is press-fitted into the spigot part 1a at the rear of the outer part 1. , is press-fitted into the spigot part 1a in the rear of the outer part 1, and the center and outer peripheral parts of the outer part 1 and the inner part 5 are brought into close contact and integrated. Finally, in order to open the center hole 9 of the air cap, the front surface 6a of the protrusion 6 of the inner part 5 is cut off, and square holes are then made at predetermined locations on the corner protrusions 3, 3, to form the air cap 10 as a whole. (see Figure 1).

Since the air cap 10 constructed in this manner has a thin wall, it has a large internal air volume and can generate a soft paint mist. Of course, since it is made of thin plate material, it is also light in weight.

<Effects of the Invention> As described above, in the air cap of the spray gun of the present invention, the inner part and the outer part are each formed by press working from thin plate materials, and the inner part is press-fitted into the outer part and fixed. However, by airtightly joining the front center part and the rear outer peripheral part, it is easier to manufacture than the conventional mold, forging, and machine cutting from a round bar. Moreover, since the wall thickness is thin, there is a large volume of space between the inner and outer parts, and the volume of space between the paint nozzle and the inner part can also be increased, which reduces the weight of the air cap and reduces work fatigue. , the impact force can be alleviated and the life of the equipment can be extended. Furthermore, the volume of the space between the inner part and the outer part can be increased, and the volume of the space between the paint nozzle and the inner part can also be increased, so each air pocket becomes larger, and the outer periphery of the tip of the paint nozzle and the inner part can be increased. The force of the air ejected from the central hole formed between the holes and the square holes formed on the protrusions on the outer part is also reduced, making the sprayed paint mist softer and less likely to scatter, resulting in a stronger paint film. It becomes smooth and the coating efficiency can also be increased. In addition, since the main processing of this air cap is press processing, there are almost no parts to be machined, which leads to a reduction in the number of processing steps and has the effect of reducing costs. The liquid handled by the spray gun of the present invention is
This includes not only paints but also adhesives and other chemicals.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of an air cap showing an embodiment of the present invention, Fig. 2 is a plan view, Fig. 3 is a front view of the outer part, Fig. 4 is a sectional view taken along the - line in Fig. FIG. 5 is a front view of the inner part, FIG. 6 is a sectional view taken along the line -- in FIG. 5, and FIG. 7 is a longitudinal sectional view of the main part of the air cap section of a conventional spray gun. 1...Outer part, 2...Through hole, 3...Protrusion, 5...Inner part, 6...Protrusion, 7...
Hole, 9...center hole.

Claims (1)

[Claims] 1. The air cap of an external mixing spray gun, which blows atomizing air from the center and pattern-forming air from the corners, is composed of an outer part and an inner part, each of which has a cylindrical shape and is made of thin plate material. A through hole is formed in the center of the outer part, at least a pair of corner protrusions are formed at symmetrical positions around the through hole, and a spigot part is formed on the inner periphery of the rear cylindrical part. A protrusion in which a center hole is formed is formed in the front center of the inner part, and a rear brim part bent toward the front is formed on the outer periphery of the rear cylindrical part. At least one hole is formed for introducing compressed air supplied from the gun body, and the through hole of the outer part and the protrusion part of the inner part are connected to the spigot part of the outer part and the protrusion part of the inner part. An air cap for a spray gun characterized by airtight connection with the rear brim.