JPS6362715A - Manufacture of helmet - Google Patents

Abstract

PURPOSE:To make hand work unnecessary and obtain a helmet, excellent in the mechanical strength of the end rim thereof, by a method wherein the helmet is molded so that one part of the inner skin of a composite material creeps around the lower rim of the helmet and forms a rim section covering the lower rim of the outer skin of a synthetic resin member by the two times shot of an injection molder. CONSTITUTION:A first molding cylinder 2 injects molten composite material A into a cavity 5, formed between molds 6, 6', through a nozzle 4. The cavity 5 consist of a central part 5A, which produces a part (shell 11) for a helmet which covers a head of a man, a turned part 5B, which becomes a rim part 12, and a connecting part 5C between the turned part 5B and the central part 5A. While the composite material is in the half-molten state thereof, the semi-molded form of the half-molten composite material A is taken out of the mold 6. Subsequently, the molds 6, 6' are connected with each other, thereafter, synthetic resin B is supplied into a second molding cylinder 2' and is injected into another cavity 5', molding an outer skin (a). The mold 6 is removed after a predetermined time to take out a molded form. The helmet 10 may be obtained from the taken-out molded form by the binding of the composite material A in half-molten state and the synthetic resin B in molten state.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is particularly applicable to bicycles, motorbikes and other motor vehicles.
This product relates to a helmet worn to protect the head in case of falls or other unforeseen accidents when riding a wheeled vehicle.

<Prior art> Helmets, especially those worn when riding two-wheeled motorbikes, have a sufficiently strong shell and a smooth surface to protect the head in the event of a fall or other unexpected accident. , color, and other surface textures that are compatible with the finish coating. To meet this demand, conventionally, when forming the shell, polyester resin was cast using glass fiber, carbon fiber, or organic fiber as a core material, or polycarbonate, vinyl chloride, etc. were used as a core material using an injection molding machine. −
Synthetic resins or composite materials mixed with inorganic or organic powders, glass fibers, carbon fibers, or organic fibers are molded, and cushioning materials such as foam molded products, air bubbles, and honeycomb materials are laminated to these materials. A helmet with a bonded two-layer structure consisting of an outer skin made of a single synthetic resin and an inner skin made of a cushioning material was produced through many laborious manual processes.

<Problems to be solved by the invention> The shell formed in this way is coated with multiple layers of sealing undercoating material to form a painted surface, which requires an extra process and reduces costs. In addition, the mechanical properties such as drop impact resistance are not necessarily sufficient, and the completed helmet has a large weight and a stiff feel that is unique to helmets, making it difficult to ride a motorcycle. In fact, they were often not worn, even if there were safety concerns.

Furthermore, in many helmets manufactured using conventional manufacturing methods, the skirt portion of the shell is not folded back.
That is, since the lower edges of each layer forming the helmet are terminated at the same level, the helmet as a whole has a sharper tone.

Suppose you try to add a folded part (edge).

As mentioned above, bonding and other complicated processes are required in the same way as for the main body part of the shell.

Means for Solving the Problems> The present invention overcomes the above-mentioned deficiencies of the conventional manufacturing method, and produces synthetic resin materials in two shots of an injection molding machine without the need for complicated processes as in the conventional method. and an inner skin of composite material (a mixture of synthetic resin material and reinforcing fibers or foaming agents), with a portion of the inner skin wrapping around the lower edge of the helmet and covering the lower edge of the outer skin. An object of the present invention is to provide a method for manufacturing a helmet having a two-layer structure.

Note that in the description of this specification, "single synthetic resin" refers to
Polypropylene or any other synthetic resin or a combination of one or more synthetic resins that are compatible with it, i.e., one or more synthetic resins that do not darken the additives within the meaning of this specification; It does not specifically represent a single type of synthetic resin.

Next, preferred embodiments of the present invention will be described in detail with reference to the drawings.

<Example> In Fig. 1, 1 is a hopper, and the composite material A described later is
That is, a composite synthetic resin, for example a mixture of polypropylene and glass fibers, is supplied. The first molding cylinder 2 has a built-in screw 3 that moves forward and backward while being rotated by an electric motor (not shown) and a transmission connected thereto. The molten composite material A is.

The mixture is injected into a cavity 5 formed between molds 6 and 6' through a mixing nozzle 4 containing a static mixer. Straddling molds 6 and 6'.

It has a bent shape as shown in FIG. That is, the cavity 5 has a substantially hemispherical central portion 5A that covers the head of the molded helmet (shell 11), and a folded portion that goes around the lower edge of the molded helmet and is folded back toward the outside. 5B (Completed helmet 10
), the folded part 5B and the center part 5A
It consists of a curved joint portion 5C between. This folded portion 5B becomes the edge 12 of the molded helmet 10 shown in FIG. by the way.

After cavity 5 is filled with molten composite B.

While this composite material is in a semi-molten state, together with the mold 6,
The semi-molten composite material A that has already adhered to this mold is taken out, and the mold 6 is placed in the mold 6' shown in the lower half of FIG. 1 assembled in the second molding cylinder 2'. Install the mold 6,6
′ are fixed together.

As shown in FIG. 1, the mold 6' extends into a region that joins the region between the central portion 5A and the folded portion 5B of the semi-molten composite material A in a substantially hemispherical shape with approximately the same width. There is. In other words, the cavity 5' is a void in which the outer skin a of the helmet 10, shown in longitudinal section in FIG. 3, would be formed if the cavity were filled with a single molten synthetic resin. . After connecting the molds 6 and 6' to each other,
A molten single synthetic resin B (for example polypropylene) is supplied from the hopper 1' into the interior of the second molding cylinder 2 and is fed through the interior of the cylinder 2' by a screw 3'. The melted resin B is.

Mixing nozzle 4' with built-in static mixer
and is injected into the cavity 5'. Once the cavity 5' is filled with resin, the mold 6 is removed after a predetermined curing time and the molded product is taken out.

The mold 6 is removed from the molded product and reattached to the mold 6' assembled to the molding cylinder 2, and the same molding cycle as described above is started again. The molded product taken out comes into contact with the single synthetic resin B in the high temperature molten state while the composite material A is in a semi-molten state, so the composite material A and the resin B are bonded to each other, resulting in the formation of the resin shown in Figure 2. A helmet 10 as a single molded product is obtained. Since the outer skin a of this helmet is made of a single synthetic resin, a smooth surface suitable for painting is obtained. In addition, the inner skin is made of a synthetic resin mixed with an appropriate foaming agent or reinforcing fibers such as glass fiber, carbon fiber, or organic fiber (the same synthetic resin as the synthetic resin of the outer skin a, or a different synthetic resin that is compatible with this). (or a combination thereof), an endothelial layer with excellent cushioning properties and mechanical strength is formed.

The single synthetic resin B used in the production method of the present invention includes polyethylene, polypropylene, polystyrene, AB
S resin, modified polyphenylene oxide (manufactured by GE, trade name Noryl), grafted polyphenylene ether (manufactured by M Dow, trade name Zylon), polyamide (nylon 6,
Nylon 66, etc.) or polycarbonate.

Composite material A is a composite of a single synthetic resin and an additive.

It may be the same as the single synthetic resin B, or it may be another resin that is compatible with it; examples of these compatible resins are polypropylene and polyethylene.

Examples include ABS resin and polystyrene, modified polyphenylene oxide and polystyrene, nylon 66 and nylon 6, or polycarbonate and ABS resin. Examples of blowing agents include azothicarbonamide (ADCA),
Examples include azobisisobutyronitrile (AZDN) and the like.

<Effects of the Invention> As explained above, according to the present invention, an integrally molded helmet 10 consisting of an outer skin a that is smooth and has good paintability and an inner skin that has excellent cushioning properties or mechanical strength can be used twice. Since it is manufactured by injection molding, it is easier to manufacture and costs are lower than conventional manufacturing methods that require bonding and other complicated manual operations. Furthermore, since the inner skin forms an edge 12 that covers the lower part of the outer skin a from the edge of the casut of the helmet 10, the cushioning properties or mechanical strength of this edge are improved.

Compared to conventional helmets in which the inner and outer skins end at the edges, the hardness characteristic of the helmet is eliminated,
You can get a helmet that feels like a luxury item.

[Brief explanation of drawings]

Fig. 1 is a partially sectional side view showing a manufacturing device used in the manufacturing method according to the present invention, Fig. 2 is a perspective view of a helmet manufactured according to the manufacturing method of the present invention, and Fig. 3 is a longitudinal cross-section thereof. It is a diagram. 6..First mold, 6'...Second mold, 61..Third mold, 10..Helmet, 12..Edge, A..
Composite material, B...synthetic resin material (single synthetic resin), a...outer skin, b...inner skin.

Claims (1)

[Scope of Claims] 1) A helmet made by injection molding of a composite material using a first mold and a second mold so as to cover all the inner surfaces of the helmet and form the edges of the outer surface thereof. forming a layer that will become the inner skin of the two-layer structure; and in a state where the layer that will become the inner skin is partially hardened, the first mold and the third
injection molding of synthetic resin material using a mold to fill the space between the part of the layer covering the inner surface of the helmet and the part of the layer forming the edge, and A method for manufacturing a helmet, comprising the step of forming a layer that will also serve as an outer skin so as to be integrated with the layer that will serve as an inner skin. 2) The synthetic resin material is made of a single type of synthetic resin or a combination of other synthetic resins that are compatible with the synthetic resin, and the composite material is made of a single type of synthetic resin that is the same as or different from the synthetic resin material or a combination thereof. 2. The manufacturing method according to claim 1, which comprises a combination of the compound and other synthetic resins that are compatible with the compound, and an additive. 3) The manufacturing method according to claim 1, wherein glass fiber, carbon fiber, or organic fiber is used as the additive. 4) The manufacturing method according to claim 1, wherein a blowing agent is used as the additive.