Method and apparatus for molding fiber mixture

A method and apparatus for molding a cushion member from a fiber mixture by a filling process comprising filling a fiber mixture composed of synthetic matrix fibers and binder fibers dispersed therein into a mold cavity of an air-permeable mold by a transportation air stream and a heat-treatment process comprising making a molding air stream for heating and/or cooling the fiber mixture filled in the mold cavity to pass through the fiber mixture, wherein a contact surface of the mold with the fiber mixture is divided into a plurality of contact sections, and a flow rate and/or pressure of an air stream passing through each of the contact sections are regulated to a predetermined condition so that the air stream in the mold cavity is differently controlled in the filling process and the heat-treatment process.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a method and an apparatus for molding a 
cushion member from a fiber mixture which is a mixture of synthetic matrix 
fibers and binder fibers dispersed therein having a melting point lower 
than that of the matrix fiber (hereinafter referred to as "fiber 
mixture"), wherein the fiber mixture is filled in a mold cavity and heated 
therein. More specifically, the present invention relates to a method for 
molding a cushion member from a fiber mixture comprising the steps of 
filling the fiber mixture in a mold cavity formed by an air-permeable mold 
by a transportation air stream and finally passing a molding air stream 
for heating and/or cooling through the filled fiber mixture and an 
apparatus therefor. 
2. Description of the Related Art 
In general, a low cost urethane foam has widely been used for forming seat 
cushion members for automobiles or airplanes having a complicated 
configuration. However, the urethane foam has drawbacks in that a toxic 
gas is generated during combustion and a recycling is difficult, whereby 
substitute therefor has long been eagerly demanded. 
To solve the above-mentioned problems, attention has recently been paid to 
a cushion member using the above-mentioned fiber mixture as a substitute 
for urethane foam. This cushion member has been formed by filling a fiber 
mixture into a mold cavity and heating the same to melt binder fibers 
contained in the fiber mixture to bond individual fibers composing the 
fiber mixture with each other. 
Also, a method for producing a cushion member from a fiber mixture is 
proposed, for example, in Japanese Unexamined Patent Publication Nos. 
2-95838 and 7-324266, wherein the fiber mixture is filled in a mold 
constructed from an air-permeable material while accompanied by a 
transportation air stream and hot air and cold air are made to flow 
through the fiber mixture filled in the mold cavity to mold the cushion 
member. This method has an advantage in that it is possible to quickly and 
uniformly heat-treat the cushion member because hot air and cold air are 
made to flow through the fiber mixture. 
However, according to the above molding method, there is a problem in that 
a high quality cushion member is not obtainable if the cushion member has 
a complicated configuration as shown in FIG. 1 which is, for example, a 
backrest of a car seat, having a pouched structure F in the upper portion 
and an upright wall D on the respective side. This is because, a condition 
required for the transportation air stream in a process for filling the 
fiber mixture in the mold cavity while accompanied by the transportation 
air stream is different from that required for a molding air stream in a 
process for passing hot air and/or cold air through the fiber mixture (in 
this respect, "hot air and/or cold air" and "molding air stream" have the 
same meaning in the present invention). Details thereof will be described 
below. 
In the process for filling the fiber mixture in the mold cavity, it is 
required that no void lacking the fiber mixture is generated within the 
mold cavity and the fiber mixture is filled at a predetermined bulk 
density. Accordingly, it is necessary to adapt the mold so that the 
transportation air stream for the fiber mixture more easily enters a 
portion of the mold cavity in which a void is liable to be generated. For 
this purpose, the air-permeability of the portion of the mold cavity in 
which a void is liable to be generated must be higher than in the other 
portion thereof. 
Contrarily, in the heat-treatment process for passing the molding air 
stream through the fiber mixture filled in the mold cavity, it is required 
to uniformly pass the molding air stream through the mold filled with the 
fiber mixture so that no molding unevenness occurs in the resultant 
cushion member. 
As is apparent from the above description, the behaviour of the air stream 
within the mold cavity is quite different between the filling process 
wherein the fiber mixture is gradually filled in the mold cavity and the 
heat-treatment process wherein the fiber mixture has already been filled 
in the mold cavity. 
Further, usually, a shape of the mold cavity in the filling process is 
different from that in the heat-treatment process unless the molding 
condition is particularly unique. This is because that since the bulk 
density of the fiber mixture is low when the same is being filled, it is 
necessary to displace the mold in the compressive direction to compress 
tie fiber mixture to obtain a predetermined bulk density, which naturally 
results in the difference in the configuration of the molding cavity 
between the filling process and the heat-treatment process. 
As stated above, the required behaviour of the air stream within the mold 
cavity is largely different between the filling process and the 
heat-treatment process in the configuration of the mold cavity, the flow 
resistance of the air stream through the fiber mixture, the flow path of 
the air stream or others. That is, the behaviour of the transportation air 
stream required for transporting the fiber mixture and that of the molding 
air stream required for converting the fiber mixture to the cushion member 
have different characteristics from each other. Thus, it is very difficult 
to obtain a high quality cushion member while avoiding a filling 
irregularity and/or the heat-treatment unevenness generated by the 
conventional molding method wherein the air-permeability of the mold is 
invariable between the filling process and the heat-treatment process in 
spite of such a large difference in the required characteristic between 
the both. 
Such a fact causes a serious problem in a mass-production of the cushion 
member because a long time, for example, 30 minutes is necessary for 
slowly increasing and lowering the temperature of the fiber mixture to 
avoid the unevenness in the heat-treatment, which results in an 
excessively long molding time to slow mass-production and increase the 
molding cost. 
To solve the above problem, there is a proposal in that a large amount of 
molding air stream is made to pass through the fiber mixture to improve 
the heat-transmission efficiency from the molding air stream to the fiber 
mixture. This method, however, requires a large flow rate of molding air 
stream which accompanies an increased air pressure. Accordingly, the fiber 
mixture which has been heated to lose its elasticity to some extent is 
liable to deform due to an influence of the large air pressure, whereby a 
thickness of the resultant product becomes thinner than the required 
thickness to deteriorate a quality of the cushion member. 
To avoid this problem, it is also conceivable to accelerate the flow rate 
of hot air until the temperature of the binder fiber reaches a softening 
point and then decelerate the flow after the softening. During the 
cooling, cold air of a low flow rate is used while the fiber mixture is in 
a molten or softened state wherein the deformation thereof is liable to 
occur, which is then accelerated at the instant when deformation hardly 
occurs. Although this method is effective to some extent for shortening 
the processing time, it is impossible to largely reduce the heat-treatment 
time required for the heating/cooling process. Accordingly, it is 
extremely difficult to shorten the molding time of the cushion member, for 
example, to 5 minutes or less and it is impossible to reduce the molding 
cost by the mass-production while maintaining a high quality. 
Also, according to a mold for molding a cushion member having a complicated 
configuration, such as a seat back as shown in FIG. 1 described above, the 
mold cavity to be filled with the fiber mixture also must have a 
correspondingly complicated configuration. Therefore, when the fiber 
mixture is filled in the mold cavity while accompanied by the 
transportation air stream, the behaviour of the transportation air stream 
within the mold cavity is difficult to control. Thus, it is extremely 
difficult to fill the fiber mixture in the mold cavity while stopping 
voids from being generated. Due to such a reason, it is very difficult to 
control the fiber mixture to be filled in the mold cavity in a desirable 
state. 
SUMMARY OF THE INVENTION 
To solve the above-mentioned problems in the prior art, an object of the 
present invention is to provide a method for molding a cushion member from 
a fiber mixture, free from a filling irregularity and a heat-treatment 
unevenness, even though the cushion member has a complicated 
configuration, as well as capable of reducing the molding time and having 
excellent productivity and quality. 
As means for achieving the object of the present invention, a molding 
method is provided, wherein an air stream is separately controlled in the 
filling process and the heat-treatment process, by dividing a contact 
surface (mold wall) of a mold with a fiber mixture filled in a mold cavity 
into a plurality of contact sections, and varying a flow rate and/or a 
pressure of the air stream passing through the respective contact section 
(mold wall) in correspondence with predetermined conditions. Also, an 
apparatus for carrying out the above molding method is provided. 
The control is carried out in such a manner that the air stream passing 
through the respective contact section (mold wall) is blown in or 
exhausted out to control the flow rate and/or the pressure of the air 
stream passing through the respective contact section in correspondence 
with a predetermined condition, or a flow rate of the transportation air 
stream passing through a contact section defining a mold cavity, wherein 
the fiber mixture is difficult to fill becomes selectively larger than 
that of the air stream passing through the other contact section. 
Further, part or all of the contact sections (mold walls) is adapted to be 
individually movable in the direction for compressing the fiber mixture 
filled in the mold cavity, i.e., upward/downward, leftward/rightward or 
forward/backward, so that the bulk density of the fiber mixture filled in 
the mold cavity is adjustable to a desirable state in accordance with the 
required characteristics. Thereby, although the respective contact section 
(mold wall) is merely movable in the one-dimensional direction, the fiber 
mixture filled in the mold cavity can be compressed in the two or 
three-dimensional direction. In addition, it is possible to carry out such 
compression not only to all of the fiber mixture filled in the mold cavity 
but also to part thereof. 
In such a manner, even in a mold cavity for molding a cushion member having 
a complicated configuration such as a backrest of a car seat or the like, 
it is possible to freely control the amount of the transportation air 
stream and/or the molding air stream passing through the contact section 
(mold wall). Moreover, it is also possible to partially control the bulk 
density of the fiber mixture filled in the mold cavity to a desired value. 
Therefore, it is possible to fill the fiber mixture in the mold cavity 
without generating a filling irregularity, whereby the unevenness of heat 
treatment is also eliminated when the fiber mixture is converted to the 
cushion member by the heat treatment. Thus, a molding method and an 
apparatus for carrying out the method, capable of reducing the molding 
time and resulting in a cushion member excellent in productivity and 
quality from a fiber mixture, are provided.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
There is no restriction in synthetic fibrous materials for constituting 
matrix fibers of the "fiber mixture" according to the present invention, 
which may include staple fibers, for example, of polyethylene 
terephthalate, polybutylene terephthalate, polyhexamethylene 
terephthalate, polytetramethylene terephthalate, poly-1,4-dimethyl 
cyclohexane terephthalate, polypivalolacton, or copolymer esters thereof, 
mixtures of such staple fibers, or staple fibers of composite fiber 
(conjugate fiber) composed of two or more kinds of the above-mentioned 
polymer components. Also, a cross-sectional shape of the staple fiber may 
be either circular, flat, non-circular or hollow. The synthetic staple 
fiber preferably has crimps, particularly apparent crimps. The apparent 
crimps may be imparted by a mechanical method such as a crimper, by an 
anisotropic quenching during the spinning or by a heat-treatment of a 
composite fiber such as a side-by-side type or an eccentric sheath/core 
type. 
On the other hand, as a binder fiber, polyurethane type or polyester type 
elastomer fibers may be used. Particularly, a composite fiber on which 
surface is exposed such elastomers are preferably used. In this regard, 
the binder fibers are, of course, dispersed and mixed in the 
above-mentioned matrix fibers at a ratio in correspondence to the required 
performance of the resultant molded product. 
The preferred embodiments of the present invention will be described below 
in detail together with the operation thereof with reference to the 
attached drawings. 
FIGS. 2A to 2C is a front sectional view of an apparatus for carrying out 
the method according to the present invention; that is, an apparatus for 
molding a cushion member from a fiber mixture by an air-blowing system. 
In these drawings, reference numeral 1 denotes a fiber mixture; 2 a 
conveyor; 3 a fiber-opener; 4 a blower; and 5 a duct, respectively. By 
employing such an arrangement, it is possible to blow the fiber mixture 1 
into a mold cavity C for the fiber mixture 1 by a transportation air 
stream. That is, the fiber mixture 1 is supplied onto the conveyor 2, and, 
after being loosened by the fiber opener 3, further supplied to the mold 
cavity C via the duct 5 while being accompanied with the transportation 
air stream generated by the blower 4. 
The mold cavity C is defined by an interior area encircled by an upper mold 
6, a lower mold 7 and side molds 8. In this regard, the upper mold 6 and 
the lower mold 7 are formed of an air-permeable material such as a punched 
plate, a metallic net or a porous plate of sintered metal. The upper mold 
6 and the lower mold 7 are individually movable while sliding on the inner 
wall surface of the side molds 8 formed of an air-permeable material 
similar to the former. Reference numeral 9 or 11 denotes an exhauster; 10 
a blower; 12 an exhaust pipe; and 14 or 15 a pair of openable damper 
provided in the upper or lower portion; wherein the behaviour of the air 
stream passing through the respective contact section (mold wall) W1 to W5 
is controlled by these devices. 
The upper mold 6 and the lower mold 7 are independently and/or dependently 
movable in the direction for compressing the fiber mixture filled in the 
mold cavity C (upward and downward in the embodiment shown in FIGS. 2A to 
2C) by the action of actuators 16 and 17, respectively. In this regard, 
the actuator 16 or 17 is preferably a fluid pressure cylinder using oil 
pressure, hydraulic pressure or pneumatic pressure, but may be a 
conventional electromotive linear motion device. In short, it is important 
that the actuator has a function for displacing the upper mold 6 and the 
lower mold 7 in the direction for compressing the fiber mixture 1. 
The present invention is characterized in that a contact surface of the 
molds 6 and 7 with the fiber mixture 1 filled in the mold cavity is 
divided into a plurality of contact sections W1 to W5 and a flow rate 
and/or pressure (dynamic pressure and static pressure) of an air stream 
passing through the respective contact section is adjusted to a 
predetermined condition, whereby the air stream in the mold cavity C is 
controlled as a whole. For this purpose, there are three contact sections 
W1 to W3 in the upper mold 6 shown in FIG. 2, while two contact sections 
W4 and W5 in the lower mold 7 and the side mold 8, respectively. 
In this regard, the respective contact section W1 to W5 are mold walls to 
be in contact with the fiber mixture 1. In the embodiment shown in FIG. 2, 
each of the lower mold 7 and the side mold 8 has one contact section W4 or 
W5, respectively. In such a manner, there may be only one contact section 
as in the lower mold 7 having the contact section W4 or a plurality of 
contact sections as in the upper mold 6 having three contact sections W1 
to W3. In this regard, in a case wherein a plurality of contact sections 
are provided, it is possible to more finely control the behaviour of the 
air stream passing through the contact surface compared with a case 
wherein only one contact section is provided, so that the molding 
condition is more precisely determined. 
The contact sections W1 to W5 thus divided are adapted to be movable in the 
direction for compressing the fiber mixture 1 as one group per mold, i.e., 
in the embodiment shown in FIG. 2, W1 to W3 in the upper mold 6, and W4 in 
the lower mold 7. However, as in an embodiment described later, the 
contact sections W1 to W5 may be individually movable. 
With reference to the apparatus shown in FIGS. 2A and 2B, the method and 
apparatus according to the present invention will be described below in 
more detail, while being classified into a filling process and a 
heat-treatment process. First, FIG. 2A illustrates a state immediately 
before the fiber mixture is blown into the mold cavity. In this state, an 
interior area of the mold cavity C is larger than in a state shown in FIG. 
2C wherein a cushion member 20 is being molded. The reason why the 
interior area of the mold cavity C is preliminarily enlarged is that a 
required bulk density (filling density) is not obtainable when the fiber 
mixture 1 is converted to the cushion member 20 solely by blowing the 
fiber mixture into the mold cavity by the transportation air stream. To 
obtain the desirable bulk density, it is necessary to compress the fiber 
mixture 1 filled in the mold cavity C by the blowing. 
Next, FIG. 2B illustrates a favorable behaviour of the transportation air 
stream during the process for filling the fiber mixture 1 by the blowing, 
wherein the transportation air stream is controlled to flow in the arrowed 
direction. In this drawing, the dampers 14, 15 provided in the upper and 
lower portions are closed. If the exhausters 9 and 11 are operated in this 
state, the transportation air stream is controlled to flow in the arrowed 
direction. 
In this case, the air-permeability of the respective contact sections W1 to 
W5 in the respective molds 6 to 8 may be individually differentiated. That 
is, with reference to FIG. 2A, the air-permeability of the contact 
sections W1 and W3 corresponding to portions of the mold cavity C through 
which the transportation air stream is difficult to pass is larger than 
that of the contact sections W2, W4 and W5 corresponding to portions of 
the mold cavity C through which the transportation air stream is easy to 
pass. Accordingly, it is possible to fill the fiber mixture 1 even in a 
portion of the mold cavity C to which the fiber mixture 1 is difficult to 
enter, whereby the generation of a void is prevented. 
In this respect, the air-permeability of the mold is freely determined, for 
example, by varying the number and/or size of holes opening in the mold. 
The behaviour of the transportation air stream in the filling process will 
be described in more detail below with reference to FIG. 2B. 
The fiber mixture 1 is not sufficiently filled in deeper portions of the 
mold cavity C having the contact sections W1 and W3 wherein the fiber 
mixture 1 is in contact with the upper mold 6. Therefore, it is necessary 
for the purpose of sufficiently supplying the fiber mixture 1 even to such 
portions to increase a flow rate (exhaust rate) through the contact 
sections W1 and W3 so that the transportation air stream for the fiber 
mixture 1 is sufficiently exhausted from the contact sections W1 and W3. 
To achieve the above object, it is necessary to control a flow rate and/or 
a pressure (dynamic pressure and static pressure) of the transportation 
air stream to a predetermined condition so that the transportation air 
stream flows in the arrowed direction in FIG. 2B. This control is carried 
out by closing the dampers 14 and 15 as shown in FIG. 2B and operating the 
exhauster 11 in this state to exhaust the transportation air stream upward 
from the upper mold 6. It is important at this time that the upper and 
lower dampers 14 and 15 are maintained in a closed state to prevent the 
transportation air stream from excessively being exhausted through the 
contact section W5 wherein the side mold 8 is in contact with the fiber 
mixture 1, whereby the pressure (static pressure and dynamic pressure) in 
the respective contact section varies and the flow rate of the 
transportation air stream increases or decreases to sufficiently fill the 
fiber mixture 1 in the deeper portions of the mold cavity defined by the 
contact sections W1 and W3. 
When the fiber mixture 1 has been sufficiently filled in the deeper 
portions of the mold cavity defined by the contact sections W1 and W3, the 
exhauster 9 disposed opposite to a position at which the duct 5 is opened 
is operated, whereby the fiber mixture 1 is sequentially filled in the 
mold cavity C starting from a portion closer to the exhauster 9. Thus the 
filling of the fiber mixture into the mold cavity C is completed. In such 
a manner, the transportation air stream is controlled to an optimum state 
so that no filling irregularity of the fiber mixture 1 is generated in the 
mold cavity C. 
In the filling process described above, the flow rate and/or pressure 
(dynamic pressure and static pressure) of the transportation air stream is 
controllable to a predetermined condition not only by the closing/opening 
of the dampers 14 and 15 but also by the adjustment of the exhaust rate or 
exhaust pressure of the exhausters 9 and 11. Also the air-permeability of 
the upper mold 6 in the contact sections W1 to W3, the lower mold 7 in the 
contact section W4 and the side mold 8 in the contact section W5 is 
preferably adjusted to the respective condition while varying a porosity 
of the molds as stated before. 
The fiber mixture 1 completely filled in the mold cavity C as stated above 
is then compressed as shown in FIG. 2C by the upper mold 6 and the lower 
mold 7 to have a desirable bulk density for the cushion member 20. In FIG. 
2C, while the upper mold 6 is solely displaced in the direction for 
compressing the fiber mixture 1, it is, of course, possible to carry out 
the compression by the displacement of the lower mold 7. 
Finally, the fiber mixture 1 is converted to the cushion member 20 through 
the heat treatment. FIG. 2C illustrates a favorable behaviour of the 
molding air stream passing through the compressed fiber mixture 1 in the 
heat-treatment process. 
In this regard, the upper mold 6 may be constructed from a plurality of 
parts corresponding to the contact sections W1 to W3, and when the 
compression is carried out by the displacement of the upper mold 6, the 
respective contact sections W1 to W3 may be independently displaced 
downward. By such a divided type mold, it is possible to impart different 
portions of the fiber mixture 1 with different bulkiness densities by 
varying the degree of compression by the respective contact section. In 
addition, it is also necessary to solve the shrinkage problem in the 
thermal molding in that the resultant cushion member 20 does not have a 
predetermined dimension due to the shrinkage during the heat-treatment 
process. For this purpose, the compression of the fiber mixture 1 may be 
carried out not only before the initiation of heat-treatment process but 
also during or after the heat treatment in a multi-stage manner. Such a 
multistage compressive heat treatment is effective for obtaining a cushion 
member 20 excellent in dimensional stability. 
The fiber mixture 1 compressed to have a predetermined bulk density as 
described above is then subjected to a heat-treatment process including a 
heating step and a cooling step. The heating step is a process for passing 
a hot air through the fiber mixture 1 and melting the binder fibers in the 
fiber mixture 1 to adhere the fibers of the fiber mixture 1 with each 
other by the molten binder fibers functioned as an adhesive. The cooling 
step is a process for passing a cooling air through the fiber mixture 1 
and solidifying the molten binder fibers to firmly bond the fibers with 
each other. The fiber mixture 1 is converted to the cushion member 20 
shaped to have an accurate configuration of the mold via these two steps. 
According to the method and apparatus of the present invention, it is 
possible to control the molding air stream passing through the fiber 
mixture 1 in the heat-treatment process, wherein the behaviour required as 
the molding air stream is different from that for the transportation air 
stream as repeatedly stated hereinbefore. To carry out such a control, of 
course, the degree of freedom is preferably as large as possible, for 
controlling the flow behaviour of the transportation air stream and the 
molding air stream. Therefore, it is favorable for the purpose of 
obtaining a sufficient degree of freedom for the control to cross the 
direction the transportation air stream for blowing the fiber mixture 1 
into the mold cavity C in the filling process generally in perpendicular 
to the direction of the molding air stream blowing into the mold cavity C 
in the heat-treatment process. 
In the heat-treatment process, part of the fiber mixture 1 is piled to have 
a larger height and a smaller width in a side area along the side wall of 
the side mold 8, i.e., the side surface of the mold cavity C, compared 
with a residual part piled in a central area of the mold cavity C, as 
shown in FIG. 2C. Accordingly, when the molding air stream flows 
upward/downward through the fiber mixture 1, there is a problem in that it 
is liable to deviate from the side area to the central area due to the 
difference in through-flow resistance between the side area and the 
central area whereby the molding air stream does not sufficiently pass 
through the part of the fiber mixture 1 piled in the side area of the mold 
cavity C in comparison with the part of the fiber mixture 1 piled in the 
central area. Particularly, the heat treatment of the fiber mixture 1 
present on the contact section W5 wherein the side mold 8 is in contact 
with the fiber mixture 1 becomes insufficient because the molding air 
stream does not pass through the contact section W5. 
This problem can be solved if it is adapted that the molding air stream 
flows not only through the contact sections W1 to W3 but also through the 
contact section W5 wherein the side mold 8 is in contact with the fiber 
mixture 1. That is, means for controlling a flow rate of the molding air 
stream is provided so that the molding air stream flows through generally 
all over the contact sections W1 to W5. In the method and apparatus 
according to the present invention, the upper damper 14 is opened and the 
lower damper 15 is closed for this purpose as shown in FIG. 2C. Thereby, 
the molding air stream is controlled to flow in the arrowed direction 
shown in FIG. 2C. In this case, the molding air stream controlled to have 
a predetermined temperature by a heat exchanger not shown is made to pass 
through the fiber mixture 1 by the blower 10 from the lower side to the 
upper side. Since the upper damper 14 is opened and the lower damper 15 is 
closed at this time, the molding air stream is exhausted not only from the 
contact sections W1 to W3 wherein the upper mold 6 is in contact with the 
fiber mixture 1 but also from the contact section W5 wherein the side mold 
8 is in contact with the fiber mixture 1 by the exhauster 11. 
As other means for controlling the air stream, a computer may be used, to 
which is stored the optimum condition of flow rate preliminarily obtained 
by experiments for the purpose of controlling the flow rate of the molding 
air stream flowing through the contact sections W1 to W5 to a desirable 
value. Based thereon, in a preferable aspect, the flow rate of the blower 
10 and that of the exhauster 11 are controlled by changing the rotational 
speed of motors for the blower 10 and the exhauster 11 via a suitable 
control means such as an inverter so that the transportation air stream 
and the molding air stream are controlled. An air stream control means 
such as a flow rate control valve or a damper may be provided in the 
exhaust pipe 12 and the blower pipe 13 to control the flow rate of the 
molding air stream to a desirable value. 
While the upper damper 14 is opened and the lower damper 15 is closed in 
the above-mentioned embodiment, the upper damper 14 may be closed and 
instead the lower damper 15 may be opened (as shown in FIG. 2C by a broken 
line) to pass the molding air stream through the contact section W5 
wherein the side mold 8 is in contact with the fiber mixture 1. In this 
case, however, the molding air stream is reversed in direction to that in 
the aforesaid embodiment wherein the molding air stream is exhausted from 
the contact section W4, and flows into the fiber mixture 1 from the 
contact section W4. 
According to a further aspect of the present invention, the mold is divided 
into a plurality of parts corresponding to the respective contact sections 
W1 to W5, each of which is provided with a chamber for adjusting the 
molding air stream to which is individually connected a blow/exhaust duct, 
so that the flow rate and pressure of the air stream in the chamber is 
controllable in correspondence with the respective blow/exhaust duct. The 
ducts connected to the contact sections W1 to W3 movable upward/downward 
must be a flexible duct such as a shrinkable/extendable bellows or a 
telescopic duct. 
The cushion member 20 obtained via the heating and cooling steps in such a 
manner is removed from the side mold 8 by displacing the actuators 16 and 
17 downward, and after being demolded from the upper mold 6 by the upward 
movement thereof, withdrawn from the molding chamber. 
FIGS. 3A and 3B are side sectional views, respectively, of a mold for 
schematically explaining a prior art method for compressing a fiber 
mixture 1 for obtaining a cushion member 20 having an upright wall 
structure D shown in FIG. 4. 
In this prior method, it is difficult to properly control the bulk density 
of the fiber mixture 1 in correspondence with the requirements for the 
respective portions. Particularly, it is difficult to uniformly fill the 
fiber mixture 1 in the mold cavity C (an area encircled by the upper mold 
6, the lower mold 7 and the side mold 8) having a narrow upright wall 
portion D shown in FIG. 4, without the lack of fiber mixture 1 in the 
upright wall portion D. To solve such a problem, the above-mentioned 
method and apparatus according to the present invention are required. 
Even if the fiber mixture 1 could be filled in the upright wall portion 
D-without a lack of fiber mixture, according to the prior art method 
wherein the upper mold 6 is displaced downward to compress the filled 
fiber mixture 1 in the upward/downward direction, it is difficult to 
control the bulk density to a required value as a whole because the 
compression of the upright wall portion D becomes insufficient relative to 
other portions. Therefore, as shown in FIG. 4, it is impossible to impart 
a predetermined hardness to the upright wall structure D of the cushion 
member 20, obtained after the completion of the thermal molding, 
corresponding to the portion D of the mold cavity C (hatched area in the 
drawing). 
To solve the drawback in the prior art method, an apparatus and method 
according to the present invention shown in FIGS. 5A and 5B are required. 
In the same manner as in FIGS. 2A to 2C, reference numeral 6 denotes an 
upper mold; 7 a lower mold; and 8a to 8b a side mold 8, respectively, 
wherein the side mold 8 includes a main body 8a, a lefthand member 8b and 
a righthand member 8c. Reference numeral E indicated by a two-dot chain 
line (imaginary line) denotes an air-blowing inlet. In this regard, there 
is a premise in FIG. 5 in that the fiber mixture has already been filled 
in the mold cavity C and a profile of the fiber mixture is eliminated for 
clarifying the drawing. 
The side mold 8 itself also constitutes side molds disposed on front and 
back sides (as seen in the direction vertical to a plane of FIGS. 5A and 
5B). The mold cavity C is defined by an area encircled by the upper mold 
6, the lower mold 7 and the side mold 8. Further, the upper mold 6 and/or 
the lower mold 7 are movable upward and downward to be capable of 
compressing the fiber mixture filled in the mold cavity C. The lefthand 
member 8b and the righthand member 8b are movable leftward and rightward, 
respectively, to be capable of compressing the fiber mixture filled in the 
mold cavity C in the leftward/rightward direction. W6 to W8 denote contact 
sections wherein the mold is in contact with the fiber mixture as in FIG. 
2. 
Small lumps of fiber mixture are filled in the mold cavity while being 
accompanied by the transportation air stream generated from a blower or 
others (not shown) through the air-blowing inlet E indicated by a two-dot 
chain line. 
In the illustrated embodiment, the air-blowing inlet E is provided on the 
front side or rear side of the main body 8a of the side mold to open to 
the main body 8a. The portion D of the mold cavity C corresponding to the 
upright structure D of the cushion member 20 is widened to a great extent 
by the leftward and rightward displacement of the lefthand member 8b and 
the righthand member 8c, respectively. 
Thereby, contrarily to the prior art method wherein the mold cavity C has a 
narrow upright wall portion D as shown in FIGS. 3A and 3B, according to 
the method and apparatus of the present invention, it is possible to 
guarantee a wide path for the transportation air stream. Further, as shown 
in FIGS. 5A and 5B, it is also possible to provide the air-blowing inlet E 
as wide as the full width of the mold cavity C widened by the lateral 
displacement of the side mold, contrary to a case wherein the side wall 
immobile in the lateral direction is used. Due to these reasons, the 
transportation air stream is fully introduced into the portion D of the 
mold cavity C to sufficiently fill the fiber mixture in the portion D of 
the mold cavity C without voids. 
When the fiber mixture has been packed in the mold cavity C in such a 
manner, the fiber mixture is compressed to be in a shape shown in FIGS. 2A 
to 2C so that the predetermined bulk density is obtained in the fiber 
mixture. The method and apparatus of the present invention are 
characterized in that the filled fiber mixture is compressed in the 
compression process not only in the upward/downward direction but also in 
the lateral direction (forward/backward and/or leftward/rightward). That 
is, the fiber mixture 1 filled in the mold cavity C is compressed in the 
two-dimensional direction or the three-dimensional direction. According to 
the above method and apparatus, it is possible for the first time to 
control the bulk density of the fiber mixture to the predetermined value 
in the forward and backward direction as well as in the leftward and 
rightward direction. That is, instead of the prior art method wherein the 
fiber mixture 1 filled in the mold cavity C is compressed in the 
one-dimensional direction, according to the present invention, the fiber 
mixture 1 is compressed in the two or three-dimensional direction, whereby 
the bulk density of the fiber mixture is truly controllable to a desirable 
value. Thus, even in the mold cavity C having the portion D elongated in 
the upward and downward direction, the control of the bulk density which 
is not achievable at all solely by the compression in the upward and 
downward direction becomes possible by the addition of the lateral 
compression. 
The configuration of the mold cavity C in an enlarged state may be 
determined to be an optimum one based on that of the mold cavity C when 
the final cushion member 20 has been obtained, while taking the required 
hardness/softness, air-permeability or others, of various portions of the 
cushion member 20, into account. 
Finally, details of one of characteristics of the present invention will be 
described in detail with reference to FIGS. 6A to 6C; FIGS. 8A and 8B; and 
FIGS. 9A to 9C, when applied to the pouched structure F provided in the 
upper portion shown in FIGS. 1A to 1C. In these drawings, the same 
reference numerals are used for denoting the same or similar parts as in 
FIGS. 2A to 2C, with the exception that reference numerals 10 and 11 in 
FIGS. 6A to 6C are different from those in FIGS. 2A to 2C, but denote 
blower/exhauster for the molding air stream. 
In FIGS. 6A to 6C, a mold cavity C is defined by a space encircled by a 
side mold 8, an upper mold 6 and a lower mold 7. That is, in FIGS. 6A to 
9C, the mold cavity C consists of filling spaces C1, C1', C2 and C2' for 
filling a fiber mixture. In this regard, the filling space C1 or C1', or 
C2 or C2' forms a unit filling space extending in the direction for 
blowing-in the fiber mixture. 
The present invention described below is characterized in that, as shown in 
FIGS. 6A, 7A, BA and 9A, the unit filling spaces C1, C1', C2 and/or C2' 
are arranged in the direction generally vertical to the air-blowing 
direction in a multi-stage manner in parallel to each other. Typically, 
the present invention is applied to the cushion member 20 having the upper 
pouched structure F shown in FIGS. 1A to 1C. In this case, two filling 
spaces consists of C1 or C1' and C2 or C2', as already described. These 
two unit filling spaces and the pair of upright wall portions D on both 
sides of the mold cavity C described with reference to FIGS. 8A and 5B are 
combined with each other to shape the pouched structure F formed in the 
upper portion of the cushion member 20. 
As illustrated in FIG. 6A, the contact sections W1 to W4 defined by the 
contact of molds 6 to 8 with the fiber mixture 1 are individually or 
groupingly movable in the direction vertical to the air-blowing direction. 
Accordingly, the fiber mixture 1 filled in the respective unit filling 
spaces is compressed to desirable compression ratios, respectively, by the 
freely movable contact sections W1 to W4. 
Further, there is a preferable aspect in that the molding air stream 
blowing into the mold cavity is reversed as shown by arrows in FIGS. 6A 
and 6C so that the unevenness in heat treatment is eliminated. This is 
because the fiber mixture 1 filled in the mold cavity C is effectively 
heated or cooled from the both sides compared with a case wherein the 
molding air stream flow solely in one direction to eliminate the 
irregularity caused by the heat treatment. 
The switching of the flowing direction of the molding air stream is carried 
out by changing the operation from a state shown in FIG. 6B wherein the 
molding air stream is generated by the blower/exhauster 10 and exhausted 
from the blower/exhauster 11 to a state shown in FIG. 6C wherein the 
molding air stream is generated by the blower/exhauster 11 and exhausted 
from the blower/exhauster 10 shown in FIG. 6C. In such a manner, the 
direction of the molding air stream passing through the mold cavity C is 
switched from an upward direction as shown by an arrow in FIG. 6B to a 
downward direction as shown by an arrow in FIG. 6C. Accompanied thereby, 
an inlet and an outlet are substantially reversed in a flow path for the 
molding air stream in the fiber mixture 1. 
It will be briefly explained below why the method and apparatus shown in 
FIGS. 6A to 6C are employed in the present invention for molding a cushion 
member 20 having a complicated configuration. In the prior art method 
shown in FIGS. 7A and 7B, when the fiber mixture 1 filled as shown in FIG. 
7A is compressed to a state shown in FIG. 7B, it is possible to compress 
the unit filling space C1 in the upward/downward direction to be the unit 
filling space C1'. However, the unit filling space C2' apparently could 
not be compressed. This means that it is impossible to freely control the 
bulk density of the fiber mixture 1 in the unit filling space C2'. This 
also means that a high quality mold product is not obtainable if it has a 
complicated configuration, such as a cushion member having a pouched 
structure, because the bulk density thereof is not adjustable. 
To solve the above problem, according to the first embodiment of the 
present invention, the fiber mixture 1 is preferentially filled in the 
unit filling space C1 as shown in FIG. 8A. It is important that the 
air-blowing inlet E for the fiber mixture 1 must be located at a position 
capable of selectively supplying the fiber mixture 1 into the unit filling 
space C1. This is because it is possible thereby to fill the fiber mixture 
1 accompanied by the transportation air stream into the respective unit 
filling space through the air-blowing inlet E. In this regard, it should 
be noted that the unit filling space C2' in FIG. 8A is not yet supplied 
with the fiber mixture 1 at this time. 
After the unit filling space C1 has selectively been fully supplied with 
the fiber mixture 1 as described above, the upper mold 6a moves downward 
as shown in FIG. 8B to displace the contact section W3 or W4 in the 
direction for compressing the fiber mixture 1. Thereby, the unit filling 
space C1 is compressed to be the unit filling space C1' shown in FIG. 8B. 
It is possible to control the bulk density of the fiber mixture 1 filled 
in the unit filling space C1 to a desired value irrespective of the unit 
filling space C2' but solely by the unit filling space C1. Of course, the 
compression ratio should be properly selected in accordance with desired 
properties of the resultant product. 
Next, as shown in FIG. 8B, the air-blowing inlet E is automatically located 
at a center of the widened unit filling space C2 as the upper mold 6a 
moves. Thereby, it is possible to fill the fiber mixture 1 in the unit 
filling space C2. At that time, the communication of the unit filling 
space C1' to the air-blowing inlet E is disconnected. As a result, the 
fiber mixture 1 is not yet supplied to the unit filling space C1'. 
Instead, thigh unit filling space C2 having a capacity for setting the 
bulk density of the fiber mixture 1 at a desired value is present as the 
upper mold 6a moves. It is important at this time to take care that the 
displacement of the upper mold 6b does not occur, otherwise the contact 
section W1 is displaced. The fiber mixture 1 is supplied from the 
air-blowing inlet E to the unit filling space C2 formed in such a state 
and fills the same. 
Thereafter, as shown in FIG. 8C, the upper mold 6b is displaced to compress 
the unit filling space C2 to be C2' so that the bulk density of the fiber 
mixture 1 in the space C2' is controlled to a desired value. In this 
state, the fiber mixture 1 is thermally molded to be the cushion member 20 
having the pouched structure. 
The filling of the fiber mixture 1 into the unit filling space may be 
carried out by a method shown in FIGS. 9A to 9C besides the 
above-mentioned one, which will be described below in more detail. 
In FIG. 9A, a plurality of air-blowing inlets E1 and E2 are provided in 
correspondence with unit filling spaces C1 and C2, respectively, which is 
the difference from the system shown in FIGS. 8A to 8C. Due to this 
structure, there is an advantage in this embodiment in that the fiber 
mixture 1 can be simultaneously supplied to the plurality of unit filling 
spaces C1 and C2. 
In FIG. 9B, a side mold 8 is movable in the arrowed direction vertical to 
the direction for blowing the fiber mixture 1 so that an air-blowing inlet 
E can confront each of a plurality of unit filling spaces C1 and C2. 
Thereby, it is possible to sequentially fill the respective unit filling 
spaces C1 and C2 through the air-blowing inlet E. 
Finally, in FIG. 9C, the fiber mixture 1 is sequentially filled in the unit 
filling spaces C1 and C2 by changing the blowing direction of the 
air-blowing inlet E in accordance with the switch motion of a deflection 
plate 18 in the arrowed direction. 
According to the present invention described above, it is possible to 
easily change the behaviour of an air stream via divided contact sections 
to be suitable, respectively, for the filling process in which the fiber 
mixture is transported by a transportation air stream and for the 
heat-treatment process in which it is necessary to quickly and uniformly 
exchange heat relative to the fiber mixture by a molding air stream. The 
divided contact sections are movable in the direction for compressing the 
fiber mixture, whereby no filling unevenness generates even in a cushion 
member having a complicated three-dimensional configuration such as a 
pouched structure and a molding time can be shortened. In addition, no 
heat-treatment irregularity occurs even though the molding time is 
shortened, whereby a cushion member is industrially obtainable, which is 
excellent in mass-productivity, cost-saving and quality.