JPH0339450B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a blow molding method for molding a cylindrical body with a mounting flange.

BACKGROUND ART Conventionally, when molding a cylindrical body such as an air duct using synthetic resin, a blow molding method is generally used. Among such cylindrical bodies, some have a flange 2 on the surface of the cylindrical body 1 as shown in FIG. 4 for attaching the cylindrical body. This cylindrical body with a mounting flange cannot be formed at the same time including the flange using conventional blow molding methods. It has been common practice to attach the formed mounting flange by bonding means such as bonding with an adhesive. As described above, this method has the drawback of requiring a process for joining the mounting flange to the cylindrical body.

An object of the present invention is to provide a mold body with a movable mold part that moves in a diagonal direction during opening and closing in a plane perpendicular to the opening/closing surface of the mold body, so that when the mold is clamped, the movable mold part is a part of the parison. Provided is a blow molding method in which a cylindrical body having an integrally formed mounting flange is molded by pinching the parison, grabbing a part of the parison by moving the parison, and then supplying air to mold the parison. It's about doing.

The details of the blow molding method of the present invention will be explained below based on Examples. Figures 1 to 3 are views showing the mold used in the blow molding method of the present invention, and among these figures, Figure 1 is a perspective view showing only one of the molds, and is symmetrical to this. Similar molds exist in different positions. FIG. 2 is a cross-sectional view of the mold in an open state, and FIG. 3 is a cross-sectional view of the mold in a closed state.

In FIGS. 1 to 3, 11 and 12 are mold bodies having recesses 11a and 12a, which are parts for forming a molded product, and 13 and 14 are diagonal directions with respect to the mold body (indicated by arrows in FIG. 2). The movable partial mold is disposed so as to be slidable in the direction shown, and has recesses 13a and 14b in a portion forming a part of the cylindrical body. The movable mold part 13 is also provided with a recess 13b forming a mounting flange. When the mold is open, a portion of this movable mold part comes out from the mold bodies 11 and 12 due to the action of a spring, etc., and also moves diagonally (diagonally to the right in Figures 1 and 2). It is located off-center. When the mold is closed, the movable mold parts 13 and 1 are moved as shown in FIG.
4 are inserted into the mold bodies 11 and 12, respectively. In the clamped state shown in FIG. 3, the recess 11a of the mold body 11 and the moving part mold 13
Also, the recess 12a of the mold body 12 and the recess 14a of the movable partial mold 14 are aligned, and these recesses constitute a part forming a cylindrical body. Reference numerals 15 and 16 indicate plates for attaching the mold body, and 17, 18, 19, and 20 indicate pins for moving the movable partial molds 13 and 14 in diagonal directions when opening and closing the mold.

Next, the blow molding method of the present invention using the mold described above will be explained.

First, as shown in FIG. 2, the parison 10 (indicated by a chain line) is fed into the mold while the mold is open. When the molds are clamped from this state, the movable mold parts 13 and 14 first come into contact. At this time, since the movable partial molds 13 and 14 are located on the right side of the position where the parison 10 is supplied, a portion of the left side portion of the parison 10 is sandwiched between both the movable partial molds 13 and 14. Become. As the mold is further tightened, the movable partial molds 13 and 14 move in diagonal directions (directions indicated by arrows in FIG. 2) relative to the mold bodies 11 and 12, respectively. In other words, the movable mold parts 13 and 14 move to the left at the same time as they enter the mold bodies 11 and 12. In this case, in practice, both mold bodies 11 and 12 approach each other, so that the movable partial molds 13 and 14 move only to the left. In this way, since the movable partial molds 13 and 14 move leftward while holding the left end of the parison 10 between them, a part of the parison is pinched outward. When the mold clamping is completed in this way, the state is as shown in FIG. 3. In other words, the parison 10 is held in the space formed by the recesses 11a, 12a of the mold bodies 11, 12 and the recesses 13a, 14a of the movable mold parts 13, 14 in a state where the parison 10 is partially pinched and pulled out. be done. Furthermore, a portion of the parison that has been grabbed is located within the recess 13b of the movable partial mold 13.

After the mold is clamped in this way, if air is sent to the parison 10, the recesses 11 of the mold bodies 11 and 12
a, 12a and recessed portions 13 of movable partial molds 13, 14
A cylindrical body having the shape formed by a and 14a is formed with a mounting flange in the shape of the recess 13b of the movable partial mold 13.

When the mold is opened after the molding is completed as described above, a synthetic resin cylindrical body such as an air duct with a mounting flange as shown in FIG. 4 is formed. When the mold is opened, the mold bodies 11, 12 and the movable mold parts 13, 14 return to the state shown in FIG. Therefore, by repeating the above-described operations, the air duct with the mounting flange can be formed again.

As explained above, according to the molding method of the present invention, a part of the parison is grabbed by moving the movable part mold, and then air is supplied and molded, which is different from the conventional blow molding method. Air ducts with mounting flanges, etc. that cannot be molded can be easily molded in a single process.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of a mold used in the blow molding method of the present invention, FIG. 2 is a cross-sectional view of the mold in an open state, and FIG. 3 is a cross-sectional view of the mold in a closed state. The cross-sectional view and FIG. 4 are perspective views of an air duct with a mounting flange formed by the blow molding method of the present invention. 11, 12... Mold body, 13, 14... Moving part mold.

Claims (1)

[Claims] 1. A mold body is provided with a split mold that can be moved diagonally to the closed plane within a plane perpendicular to its opening/closing surface, and when the mold is clamped, a part of the parison is first sandwiched between the split mold parts. A blow molding method for forming a cylindrical body with an attachment flange, in which a cylindrical body is formed by supplying air after grabbing a sandwiched part of a parison by moving a split mold.