JPH0239780Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a mold for molding a urethane foam molded body having a bag-shaped portion such as a seat bag for an automobile.

In recent years, for the purpose of automobile safety measures and reducing seat assembly man-hours, the front seat backs have been formed into a bag shape to improve safety in the event that rear seat occupants hit their head or chest against the back of the front seat during a sudden stop. Countermeasures have been taken to increase the height of the seat bag and to facilitate the installation work when attaching the foam molded body to the seat bag frame.

The bag-shaped portion has a shape as shown in A in FIG. 1, where 1 is a urethane foam molded body, 2 is a frame, and 3 is a cover material. In order to mold a urethane foam molded product with such a shape, a second
Generally, a mold having a core mold 6 in addition to an upper mold 4 and a lower mold 6 as shown in the figure is used. It is pushed up by the foaming pressure against the 4th surface of the mold to form a bag-shaped portion on the back side.

However, recently, in order to improve productivity, urethane foam stock solutions with fast-reacting formulations are often used, and foam hardening often progresses without completely forming the back side pouch-shaped part, resulting in defects in thickness. There were drawbacks that led to this.

In order to overcome these drawbacks, a method has been adopted in which the urethane foam stock solution is manually sprinkled on the upper mold side of the core mold, but this method has the drawback of requiring labor.
A countermeasure was desired.

The inventors of this application attempted to solve the problem by an extremely simple method of providing a through hole in the core mold, but when a through hole with a circular cross section was provided, the urethane foam stock solution naturally entered the through hole. Since the urethane foam molded product is foamed and hardened, if the foam at the penetration part of the through hole is not cut with a knife or by hand, the urethane foam molded product will be torn during demolding, and the foam filled in the through hole will be damaged. A problem arises in that it is difficult to remove the foam pieces.

As a result of various studies on this improvement, the inventors of the present application made the through hole conical as shown in Figure 3, and made the upper surface elliptical and the lower surface circular, thereby making the urethane foam molded object simply free. The foam that has entered the conical through-hole can be torn off very easily by simply pulling it up to the end, and the foam that remains inside the through-hole can be easily removed by poking it from the top side with a rod-shaped object, so there is no need to worry about chipping or chipping. This made it possible to obtain a good urethane foam molded product without tearing.

As shown in FIG. 3, the conical through hole 7 provided in the core mold has an elliptical major axis a of 8 mm on the upper surface side.
The above is preferably 10 to 20 mm, the minor axis b is 5 to 15 mm, and the diameter of the circle on the bottom side is 10 m/m or more, preferably 10 to 30
It is preferable to select it within the range of mm.

If each of these dimensions is reduced to 5 m/m or less, when the urethane foam stock solution penetrates and hardens, free foaming will be inhibited, resulting in a high-density foam that cannot be easily torn off, and must be avoided. Furthermore, even if it is torn off, the foam around that part is hard, so it has the disadvantage of causing a strange feeling. The reason why the upper surface is elliptical is extremely effective in making it easier to tear. From the point of view of on-site forming processing, the material of the lower forming die shown in FIG. 2 may be made of iron sheet metal or may be an aluminum casting die.

Further, the core mold may be formed by a combination of aluminum casting and iron sheet metal processing.

The mold of the present invention has a specially shaped through hole as described above in the core mold, so when molding a bag-shaped cushion body, the urethane foaming stock solution is applied to the back side (upper mold side) of the bag-shaped part. As a result, a molded product of good quality with no worries about underfilling or tearing can be obtained, and the foam pieces remaining in the through holes can be removed extremely easily, so that
It was possible to work without delay even in the case of a mold mounted on a conveyor line moving at a speed of more than m.

[Brief explanation of the drawing]

Fig. 1 is a side view of the assembled soft polyurethane foam molded product obtained by the present invention, Fig. 2 is a perspective view of a mold showing an embodiment of the present invention, and Fig. 3 is a view of the through holes. It is a perspective view showing a shape. 1... Urethane foam molded body, 2... Frame, 3... Cover material, 4... Upper mold, 5... Lower mold,
6... Core type, 7... Through hole.

Claims (1)

[Claims for Utility Model Registration] (1) In a polyurethane foam mold consisting of an upper mold, a lower mold, and a core mold, at least one conical through hole is provided on the free edge side of the core mold. Characteristic mold for soft polyurethane foam. (2) The mold for flexible polyurethane foam according to claim 1, wherein the conical through hole provided in the core mold has an elliptical upper surface and a circular lower surface.