JPH0417B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention (1) Industrial Field of Application The present invention relates to a method for molding a foam styrene shock absorbing liner for a helmet, which is fitted into the inner surface of the shell of the helmet.

(2) Prior Art Conventionally, in producing a foam styrene molded article having different types of layers, each layer is individually molded, and then the different types of layers are polymerized and bonded together using an adhesive.

(3) Problem to be solved by the invention In the conventional method, for example, a dome-shaped low-density first layer having a recess on the outer surface of the forehead, and a high-density layer that fills the recess and is bonded to the first layer. When attempting to mold a foam styrene shock absorbing liner comprised of a second layer of , not only many molds are required, but there are also many work steps, resulting in high product costs.

Therefore, the present invention has been developed to form a foam styrene shock absorbing liner for helmets, which requires only one mold for molding and can bond different layers together without an adhesive process, with extremely high work efficiency. The purpose is to provide a method.

B. Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention includes a dome-shaped low-density first layer having a concave portion on the outer surface of the forehead;
a high-density second layer that fills the recess and is bonded to the first layer, and is fitted to the inner surface of a shell of a helmet; A cavity corresponding to the first layer is defined by a core mold having a protruding molding surface corresponding to the second layer, and a mold formed of foam styrene is formed in the cavity. filling the first pre-expanded particles with the first pre-expanded particles; heating and expanding the first pre-expanded particles to such an extent that the particles locally fuse with each other; and removing the core mold from the cavity.
filling the recesses formed in the traces with second pre-expanded foam styrene particles having a smaller pre-expansion ratio than the first pre-expanded particles; and heating and expanding the first and second pre-expanded particles. The method is characterized in that it has a step of completely melting the particles together.

(2) Effect According to the above configuration, the first
At the same time, forming the first layer using the pre-expanded particles and forming the second layer using the second pre-expanded particles,
Both the first and second layers can be extremely firmly fused over the entire wide boundary surface between the two layers. Moreover, especially in the forehead of the formed shock absorbing liner, the inner low-density first layer absorbs relatively small impact energy, while the outer high-density second layer absorbs relatively large impact energy. Therefore, large impact energy can be absorbed without applying large impact force to the user's head.

In particular, the difference in density between the first and second layers can be easily obtained by varying the pre-expansion ratios of the first and second pre-expanded foam styrene particles constituting both layers, as described above.

(3) Embodiment An embodiment of the present invention will be described below with reference to the drawings.

First, referring to FIG. 1, a helmet equipped with a shock absorbing liner manufactured by the method of the present invention will be described. A helmet 1 includes a shell 2 made of hard reinforced resin and a foam styrene fitted on the inner surface of this shell 2. It is composed of a shock absorbing liner 3 made of The shock absorbing liner 3 also has a dome-shaped low-density first liner having a recess 4a on the outer surface of the forehead.
It is composed of a layer 4 and a high-density second layer 5 that fills the recess 4a and is bonded to the first layer 4.

Therefore, especially in the forehead region of the impact absorbing liner 3, the low density first layer 4 can absorb relatively small impact energy, and the high density second layer can absorb relatively large impact energy. As a result, large impact energy can be absorbed without applying large impact force to the user's head.

Next, the molding apparatus for the shock absorbing liner 3 will be described. As shown in FIG. At this time, a cavity 8 for molding the first layer 4 of the impact absorbing liner 3 is defined between them. Each mold 6, 7 is hollow,
A steam supply device 9, a cooling water supply device 10, and a cooling air supply device 11 connected to the hollow parts 6a, 7a are connected to each mold 6, 7, and each mold 6, 7 has a hollow part 6a, 7a and a cavity. A large number of pores 12, 12, . . . , 13, 13, .

A first injector 15 is attached to the female mold 6 for feeding pre-expanded particles into the cavity 8 from a portion corresponding to the top of the first layer 4.

Further, the female mold 6 includes a core mold 19 having a molding surface 19a corresponding to the second layer 5 and capable of retracting into the cavity 8 at a portion corresponding to the recess 4a, and a core mold 19 that allows the foamed particles to flow from the core mold 19 into the cavity 8. A second injector 16 for feeding the core mold 19 is provided.
A large number of pores 14, 14, . . . that communicate between the hollow portion 6a and the cavity 8 are also bored.

The second injector 16 is integrally connected to the core mold 19, slidably supported by the female mold 6, and connected to the drive piston of the hydraulic cylinder 20. When the driving piston of the fluid pressure cylinder 20 is reciprocated, the core mold 19 is moved into the cavity 8 via the second injector 16, and
It can then be moved to a retreat position.

Now, to explain the molding process of the shock absorbing liner 3, first, as shown in FIG. Injector 1
The first pre-expanded particles 1 of foam styrene are passed through the cavity 8 through the foam styrene and have a relatively large pre-expansion ratio.
7, and then the steam supply device 9 is operated to supply high-temperature steam to the hollow parts 6a and 7a of each mold 6 and 7. Then, the water vapor enters the pores 12,1
3 and 14 into the cavity 8 to efficiently heat and expand the first pre-expanded particles 17, but at a stage where the heating time is controlled to cause the second pre-expanded particles 17 to locally fuse with each other. The expansion of the first pre-expanded particles 17 is temporarily suppressed by stopping the supply of steam and operating the cooling water supply device 10 to supply cooling water to the hollow parts 6a and 7a. Instead of such water cooling, air cooling may be performed by operating the cooling air supply device 11.

Then, by operating the fluid pressure cylinder 20, the core mold 19 is moved back to create a recess 4a, and the second pre-expanded particles 18 of foam styrene having a relatively small pre-expansion ratio are filled into the recess 4a through the second injector 16. Then, the steam supply device 9 is operated again, and the first,
Efficiently heat the second pre-expanded particles 17 and 18;
It is expanded and the particles are completely fused to each other.

In this way, the first pre-expanded particles 17
The layer 4 is molded, and the second layer 5 is molded by the second pre-expanded particles 18. However, since the former particles 17 have a large pre-expansion ratio and the latter particles 18 have a small pre-expansion ratio, the first layer 4 is low density, second layer 5
will be molded with high density.

By the way, since the second pre-expanded particles 18 have a smaller pre-expanded ratio than the first pre-expanded particles 17, when they are heated and expanded, the second pre-expanded particles 18 moderately expand the first pre-expanded particles 17. As a result, the density of the portion of the first layer 4 adjacent to the second layer 5 in the thickness direction takes an intermediate value between the other portions of the first layer 4 and the second layer 5.

Thereafter, the cooling water supply device 10 and the cooling air supply device 11 are sequentially operated to undergo water cooling, air cooling, and air cooling processes, and then the mold is opened, and the molded product, that is, the shock absorbing liner 3 is taken out from the cavity 8.

C. Effects of the Invention As described above, according to the present invention, there is a dome-shaped low-density first layer having a recess on the outer surface of the forehead, and a high-density layer that fills the recess and is bonded to the first layer. 2
A method for molding a foam styrene shock absorbing liner for a helmet which is comprised of a layer and is fitted to the inner surface of a shell of a helmet, the method comprising: a mold that can be opened and closed, and a layer corresponding to the second layer in the outer mold. defining a cavity corresponding to the first layer with a core mold having a protruding molding surface, and filling the cavity with first pre-expanded foam styrene particles;
a step of heating and expanding the first pre-expanded particles to such an extent that the particles are locally fused together; and a step of removing the core mold from the cavity and inserting the first a step of filling second pre-expanded particles of foam styrene with a smaller pre-expansion ratio than the pre-expanded particles; and a step of heating and expanding the first and second pre-expanded particles to fuse the entire surface of the particles. Since the first layer is molded by the first pre-expanded particles and the second layer is molded by the second pre-expanded particles in the mold with a core mold, both the first and second layers are simultaneously molded. The first and second
A high-quality shock absorbing liner without peeling between layers can be formed at low cost. Moreover, the inner low-density first layer of the shock absorbing liner after molding, especially in the frontal area,
layer can absorb a relatively small impact energy, while the outer dense second layer can absorb a relatively large impact energy, thus preventing large impacts without imparting large impact forces to the user's head. Since the second layer is on the outside of the liner and is covered by the shell when the liner is fitted into the shell, the first layer
There is no fear that the boundary of the second layer will be exposed to the outside and the appearance of the helmet will be impaired.

In particular, the density difference between the first and second layers can be easily obtained by simply varying the pre-expansion ratios of the first and second foam styrene pre-expanded particles, which constitute both layers, as described above. Therefore, the first and second layers having different densities can be easily molded from the same foam styrene material, which can contribute to cost reduction and improve the fusion properties between the first and second layers.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a cutaway side view of a main part of a helmet equipped with a shock absorbing liner molded by the molding method of the present invention, and FIGS. 2 and 3 are main parts of a molding device. FIG. 3... Shock absorbing liner, 4... First layer, 4a...
... Concavity, 5 ... Second layer, 6 ... Female mold as mold, 7 ... Male mold as mold, 8 ... Cavity, 17, 18 ... First and second pre-expanded particles, 1
9... Core mold, 19a... Molding surface.

Claims (1)

[Claims] 1 Consisting of a dome-shaped low-density first layer 4 having a recess 4a on the outer surface of the forehead, and a high-density second layer 5 that fills the recess 4a and is bonded to the first layer 4, A method for molding a foam styrene shock absorbing liner for a helmet to be fitted into the inner surface of a shell 2 of a helmet 1, the molds 6 and 7 being openable and closable.
A core mold 19 having a protruding molding surface 19a corresponding to the second layer 5 in the molds 6 and 7 defines a cavity 8 corresponding to the first layer 4. a step of filling the first pre-expanded particles 17 of foam styrene into the core mold 19; a step of heating and expanding the first pre-expanded particles 17 to such an extent that the particles 17 are locally fused together;
are removed from the cavity 8, and the first pre-expanded particles 1 are placed in the concave portion 4a formed in its place.
filling the second pre-expanded particles 18 of foam styrene with a pre-expansion ratio smaller than 7; heating the first and second pre-expanded particles 17, 18;
A method for molding a foam styrene shock absorbing liner for a helmet, comprising the step of expanding and fusing the particles 17 and 18 over the entire surface.