JPH0551786B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a synthetic resin float for a vaporizer.

When manufacturing conventional synthetic resin floats for vaporizers, a pair of float component parts (including asymmetrical ones such as a float body and a lid) are injection molded, and these two parts are joined to form a hollow float. was forming. One of the bonding methods, for example, is bonding with adhesives.In addition to the long drying time required for the adhesive used for this type of bonding, the float is in an airtight state, which makes the drying time even longer. There was a problem of being inferior in gender.
In addition, the adhesive tends to protrude from the bonded area, resulting in a loss of appearance, or the adhesive tends to adhere to other functional parts, causing a false solidity and impairing the float function.
There was a problem that it caused quality defects. or,
In the case of joining by heat welding, the float itself is generally small, so the heat during welding expands the air inside the float, and the expansion pressure causes the softened joint to break. There have been problems in that the expansion pressure may cause joint defects, or the thickness of the joint may become thinner due to the expansion pressure, significantly deteriorating the reliability of the float function, resulting in quality defects.

Therefore, in order to solve the problems of both the above-mentioned joining methods, for example, Japanese Patent Publication No. 49-38649 and Japanese Patent Publication No.
As in the method described in Publication No. 57-34450, a through hole is provided in a part of the constituent members, and in the case of adhesive bonding method, drying time of the adhesive is shortened by air circulation, and bonding method by thermal welding is used. In this case, it has been proposed to prevent the joint from breaking or becoming thinner by releasing the expansion pressure, but this method requires the formation of the above-mentioned through hole, which complicates the injection mold for the component. There was a problem.

In view of the above-mentioned problems, the present invention aims to provide a method for manufacturing a synthetic resin float that greatly simplifies injection molding molds for component parts while increasing mass productivity and preventing quality defects. It is something to do.

The method for manufacturing a synthetic resin float according to the present invention includes:
The construction is made by first heat welding the joint part except for a part, and then heat welding that part, so that the expansion pressure of air is released from the unwelded part at the first heat welding stage. This eliminates the need to provide a through hole in the member.

Hereinafter, the present invention will be explained in detail based on one embodiment shown in FIGS. 1 to 3. 1 is a horseshoe-shaped container made of synthetic resin, in which a float arm 2 and a needle valve opening/closing control section 3 are integrally formed. A welding margin 1a and a stepped portion 1b are formed along the opening edge of the float body. Reference numeral 4 denotes a horseshoe-shaped synthetic resin lid that has appropriate flexibility and can be fitted into the opening of the float body 1, and a welding margin 4a and a stepped portion 4b are formed along the outer periphery of the lid. has been done. 5 is a heating plate, and 6 is a welding metal having a low temperature part 6a made of a material with low thermal conductivity on a part of its upper surface (the part that can come into contact with the welding margins 1a and 4a) placed on the heating plate 5. It is a type.

According to the present invention, the float main body 1 and the lid 4
A float is manufactured by joining as follows. That is, first, as shown in FIG. 1, the lid 4 is fitted into the opening of the float body 1 so that both stepped portions 1b and 4b are joined, and then the whole is turned over and a welding mold is formed as shown in FIG. 6 and press from above to weld both welding margins 1a and 4a.
At this time, since the portion that contacts the low temperature portion 6a remains as an unwelded portion, the expansion pressure of the air expanded by heating escapes through a small gap in the unwelded portion as shown in FIG. Therefore, the welded joint portion is not torn or thinned due to expansion pressure, and quality defects are reliably prevented. Next, after the joint parts are cooled and solidified, the unwelded parts are welded using a welding die or an ultrasonic tool (not shown), thereby completing a hollow float. Although the float is manufactured as described above, unlike the conventional method, there is no need to provide a through hole in the float body 1 or the lid 4, so the mold for injection molding these members becomes extremely simple. Furthermore, since the method of the present invention is a bonding method using thermal welding, the bonding time is extremely short, and it is inherently more suitable for mass production than bonding methods using adhesives. Mass production is further improved due to the simpler mold.

In addition, if a notch 1c is provided in the unwelded part as shown in FIG. 4, which is large enough to be completely welded in the second welding process, the expansion pressure of the air in the float will be reduced during the first welding process. Since the particles escape to the outside more easily, it is possible to more reliably prevent the joint from breaking or becoming thinner. Further, in this case, there is no need to provide the low temperature part 6a in the welding mold 6.

As mentioned above, the method for manufacturing a synthetic resin float for a vaporizer according to the present invention has the important practical advantage of being able to greatly simplify the injection molding mold for the component while increasing mass productivity and preventing quality defects. have.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the state before bonding of a synthetic resin float for a vaporizer manufactured by an embodiment of the method of the present invention, FIG. 2 is a longitudinal sectional view showing the first welding process of the float, and FIG. FIG. 3 is a longitudinal sectional view showing the first welding state of the float, and FIG. 4 is a perspective view showing another example of the float body. 1... Float body, 1a... Welding allowance, 4...
Lid, 4a... Welding allowance, 5... Heating plate, 6... Welding mold, 6a... Low temperature part.

Claims (1)

[Claims] 1. In a method for manufacturing a synthetic resin float for a vaporizer in which a pair of injection-molded float components are joined to form a hollow float, a part of the joined part is once removed by heat welding, and then the A manufacturing method characterized by thermally welding a portion.