U.S. patent application number 10/795244 was filed with the patent office on 2004-12-23 for trim cover assembly.
This patent application is currently assigned to TACHI-S CO., LTD.. Invention is credited to Takei, Yoshiyuki.
Application Number | 20040256904 10/795244 |
Document ID | / |
Family ID | 33516201 |
Filed Date | 2004-12-23 |
United States Patent
Application |
20040256904 |
Kind Code |
A1 |
Takei, Yoshiyuki |
December 23, 2004 |
Trim cover assembly
Abstract
A trim cover assembly formed by sewing together a plurality of
cover materials into a three-dimensional configuration which is to
undergo a foaming process in which a liquid foaming agent is
injected into the trim cover assembly and a resultant foam padding
is filled therein. Each of the cover materials comprises a top
cover layer and a slab foam wadding layer fixed to a reverse side
of the top cover layer. The slab foam wadding layer is of a
continuous cellular structure having an air permeability of from
0.2 cc/cm.sup.2/sec. to 1 cc/cm.sup.2/sec. so that, during the
foaming process, the liquid foaming agent is impregnated and cured
in the slab foam wadding layer at a proper rate relative to the
thickness of the latter so as not to reach the top cover layer.
Inventors: |
Takei, Yoshiyuki; (Tokyo,
JP) |
Correspondence
Address: |
BROWDY AND NEIMARK, P.L.L.C.
624 NINTH STREET, NW
SUITE 300
WASHINGTON
DC
20001-5303
US
|
Assignee: |
TACHI-S CO., LTD.
Tokyo
JP
|
Family ID: |
33516201 |
Appl. No.: |
10/795244 |
Filed: |
March 9, 2004 |
Current U.S.
Class: |
297/452.48 |
Current CPC
Class: |
B29C 44/1209 20130101;
B29C 44/145 20130101; B60N 2/5891 20130101; B60N 2/7017
20130101 |
Class at
Publication: |
297/452.48 |
International
Class: |
A47C 007/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 19, 2003 |
JP |
2003-174270 |
Claims
What is claimed is:
1. A trim cover assembly formed by sewing together a plurality of
cover materials into a three-dimensional configuration which is to
undergo a foaming process in which a liquid foaming agent is
injected into said trim cover assembly and a resultant foam padding
is filled therein, wherein each of said plurality of cover
materials comprises: a top cover layer having an outer surface side
and a reverse side; and a slab foam wadding layer integrally
laminated on said reverse side of said top cover layer, and wherein
said slab foam wadding layer is of a continuous cellular structure
having an air permeability of from 0.2 cc/cm.sup.2/sec. to 1
cc/cm.sup.2/sec.
2. The trim cover assembly as claimed in claim 1, where said to
cover layer is of an air permeable property.
3. A foamed product using said trim cover assembly claimed in claim
1, which is formed by the foaming process comprising the steps of
placing said trim cover assembly in a foaming die, injecting said
liquid foaming agent into an inside of said trim cover assembly,
and subjecting the trim cover assembly and said liquid foaming
agent to foaming, under such a condition that a foaming pressure is
set relative to a thickness of said slab foam wadding layer at a
rate that allows the liquid foaming agent to be impregnated in at
most half of thickness of said slab foam wadding layer.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a surface cover material or
what is called "trim cover" for vehicle or automobile, which covers
a body of automotive seat, headrest, armrest or the like. In
particular, the invention is directed to a trim cover assembly of
this kind formed by sewing together cover materials into a
three-dimensional configuration which is suited for a foaming
process where a liquid foaming agent is injected in the trim cover
assembly and subjected to foaming and curing therein.
[0003] 2. Description of Prior Art
[0004] Among various sorts of trim cover assemblies, there has been
known such trim cover assembly as disclosed in the Japanese
Laid-Open Patent Publication No 63-35314, which is formed by sewing
together a plurality of three-layer laminated cover materials each
comprising an air permeable top cover layer, a slab foam layer
(i.e. an urethane soft foam layer) adhered to the reverse side of
the top cover layer, and an impermeable film laminated to the slab
foam layer.
[0005] The foregoing publication teaches a foaming process
involving the steps of placing the thus-formed three-dimensional
trim cover assembly in a foaming die, then injecting a liquid
foaming agent into the inside of that trim cover assembly, and
finally having the agent foamed and cured into an increased mass of
foam padding body which is filled in the trim cover assembly at a
predetermined degree of foaming pressure, while simultaneously, the
trim cover assembly is forcibly brought by that foaming pressure to
intimate contact with a whole of inner walls of a foaming die. As
consequence thereof, a desired shape of foamed product, such as a
headrest, is formed.
[0006] It has been found defective that this sort of trim cover
assembly having an impermeable film therein is prone to partial
breakage and opening, such as a local opening along a seam, due to
the increased foaming pressure in the die, thus undesirably
resulting in leakage of the liquid foaming agent through the
opening to the outside, and further, it has been frequently the
case that, during that foaming process, an air is trapped in the
curing foam layer portion adjoining with the impermeable film to
form undesired hollow regions in the resultant foamed padding since
the air is not escaped through such impermeable film. It has been
therefore necessary to provide a special step or material for
preventing the breakage and leakage problem as well as for avoiding
the air trap problem.
[0007] On the other hand, the foregoing problems are not found for
such a permeable two-layered lamination of trim cover assembly that
comprises an air permeable top cover layer and a slab foam layer,
which allows for escape of air therethrough and decrease foaming
pressure in the foaming die. Nonetheless, another problem has been
with this two-layered type of trim cover assembly. That is, during
the foaming process, it has been the frequent case that the air is
easily escaped through the two layers of trim cover assembly,
thereby making it difficult to retain a proper degree of forming
pressure in the die, as a result of which, some of the resultant
foamed products can not achieve a desired precise outer
configuration and might create objectionable creases and slack
portions on the resultant trim cover assembly. Moreover, in this
case, during the foaming steps, the liquid foaming agent is
impregnated in the inner cellular structure of the slab foam layer
and cured therein to create hardened portions which will impair the
cushiony touch of the trim cover assembly.
SUMMARY OF THE INVENTION
[0008] In view of the above-stated drawbacks, it is a purpose of
the present invention to provide an improved trim cover assembly
having a neatly finished outer surfaces without any crease and
slack portion therein, with a normal soft touch given thereto.
[0009] In order to achieve such purpose, in accordance with the
present invention, there is provided a trim cover assembly formed
by sewing together a plurality of cover materials into a
three-dimensional configuration which is to undergo a foaming
process in which a liquid foaming agent is injected in the trim
cover assembly and filling a resultant foam padding therein,
wherein each of the plurality of cover materials comprises:
[0010] a top cover layer having an outer surface side and a reverse
side; and
[0011] a slab foam wadding layer integrally laminated on the
reverse side of top cover layer,
[0012] and wherein the slab foam wadding layer is of a continuous
cellular structure having an air permeability of from 0.2
cc/cm.sup.2/sec. to 1 cc/cm.sup.2/sec.
[0013] Accordingly, owing to such air permeability of from 0.2
cc/cm.sup.2/sec. to 1 cc/cm.sup.2/sec., under a proper degree of
foaming pressure, a liquid foaming agent is impregnated in the slab
foam wadding layer at a proper impregnation rate relative to a
thickness of the latter to such a degree that the liquid foaming
agent or a resulting cured film, which is impregnated in the slab
foam wadding layer, does not reach the top cover layer, while also
causing the trim cover assembly to be uniformly stretched by an
increased mass of foam padding being formed from the liquid foaming
agent, without any crease and slack portion created in the outer
surfaces of the trim cover assembly.
[0014] Other various aspects, features and advantages of the
present invention will become apparent from reading of the
description, hereinafter, with reference to the annexed
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a sectional view showing the state that a trim
cover assembly of the present invention is placed in a foaming die
prior to a foaming operation and a liquid foaming agent is injected
into the inside of the trim cover assembly;
[0016] FIG. 2 is a fragmentary sectional view of the trim cover
assembly;
[0017] FIG. 3 is a sectional view showing the state that the
foaming process is completed and a foam padding is filled in the
trim cover assembly; and
[0018] FIG. 4 is an enlarged section fragmentary in part, which
shows a point corresponding to the circle indicated by "V" in the
FIG. 3.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION
[0019] Referring to FIGS. 1 to 4, there is illustrated one
exemplary mode of trim cover assembly (T) in accordance with the
present invention, which is to undergo a subsequent foaming
process.
[0020] As can be seen from the cross-sectional view of FIG. 1, the
trim cover assembly (T) is formed by sewing together a plurality of
separate cover materials (A) into the illustrative
three-dimensional configuration. Designations (A1) denote sewn
connection corner portions of the thus-formed trim cover assembly.
As far as the present embodiment is concerned, the trim cover
assembly (T) is of such a generally cubic shape conforming to a
predetermined outer shape of a headrest, by way of example, and has
an injection hole (A2) formed in one wall of the trim cover
assembly (T) in order to allow insertion of an injection nozzle
therethrough as will be explained later.
[0021] FIG. 1 shows, in cross-section, a first foaming die (40) and
a second foaming die (41), which are fit engageable with each other
so as to receive the foregoing trim cover assembly (T) therein for
a subsequent foaming process.
[0022] In accordance with the present invention, each cover
material (A) of the trim cover assembly (T) is comprised of a top
cover layer (1) and a slab foam wadding layer (2) laminated to the
reverse side of the top cover layer (1).
[0023] The top cover layer (1) is such a known air-permeable
material as a woven material, non-woven fabric, a leather material
or any other proper air-permeable cover material normally used for
a vehicle seat, headrest, armrest or other interior items in a
vehicle or automobile.
[0024] But, the slab foam wadding layer (2) in the present
invention is formed from a soft urethane foam material with a
continuous cellular structure. As will be elaborated, its thickness
is preferably 3 mm to 8 mm, and an air permeability of that foam
wadding layer (2) is preset within the range from 0.2
cc/cm.sup.2/sec. to 1 cc/cm.sup.2/sec.
[0025] Now, a description will be made of a foaming operation to
subject the above-described trim cover assembly (T) to foaming in
the dies (40) (41) on the understanding that a resulting foamed
product or a resulting headrest (P) is to be formed thereby for
instance.
[0026] At first, a preformed three-dimensional trim cover assembly
(T) with the above-discussed two-layer and air-permeable structure
is provided. A pair of suitable first and second die elements (40)
(41) are also provided, which each has a predetermined shape of
inner die surface conforming to a half of the outer shape of the
trim cover assembly (T). Designation (42) denotes a through-hole
formed in the mating boundaries respective of the first and second
die elements (40) (41), which is adapted for allowing insertion of
an injection nozzle (N) therethrough. Although not shown, the
injection nozzle (N) is operatively connected with a suitable
supply device for supplying a liquid foam agent thereto, so that,
in operation, a certain amount of the liquid foam agent (L) is
injected from the nozzle (N) in such a manner as seen in FIG.
1.
[0027] Then, as shown in FIG. 1, an entirety of the trim cover
assembly (T) is placed in position within the mated first and
second die elements (40) (41), while disposing a headrest frame (C)
centrally of the two die elements, such that the injection hole
(A2) of the trim cover assembly is aligned with the through-hole
(42) of the die elements (40) (41). Under such state, the injection
nozzle (N) is inserted through those two aligned holes (A2) (42)
and then a predetermined amount of the liquid foam agent (L) is
injected from the nozzle (N) into the inside of the trim cover
assembly (T).
[0028] At this stage, it is important to preset the amount of the
liquid foam agent (L) to be injected in the trim cover assembly
(T), because it is a factor for determining the degree of foaming
pressure as known in the art. Thus, a proper amount of the liquid
foaming agent (L) is injected in the trim cover assembly (T) in
order to impregnate that particular liquid foam agent in a
predetermined depth of the slab foam wadding layer (2) and thereby
form an appropriate impregnation ratio (at l2, say, about 30% to
40%, for instance) of cured foaming agent or an impermeable film,
as indicated by (20), relative to a whole thickness (l1) of the
slab foam wadding layer (2). That is, it is an essential aspect of
the present invention to avoid full occupation of such film (20) in
the slab foam wadding layer (2) and also to prevent that film (20)
from reaching the top cover layer (1), as shown in FIG. 4.
Preferably, the liquid foaming agent (L) should be impregnated in
at most half of the thickness of the slab foam wadding layer
(2).
[0029] For that purpose, for example, suppose that the thickness of
the slab foam wadding layer (2) is 5 mm, it is found optimal to set
the foregoing degree of foaming pressure to approximately 0.1 kg in
order to successfully maintain the above-noted impregnation
proportion of the liquid foaming agent (L) in the 5 mm thickness of
slab foam wadding layer (2), which substantially corresponds to the
designation (l2) shown in FIG. 4. This was confirmed by experiments
conducted on a number of different sample cover materials each of
this kind of two-layer structure having such air permeable top
cover layer and slab foam wadding layer with different sizes and
scales.
[0030] Now, in practice, a foaming is effected to an entirety of
the trim cover assembly (T), frame (C) and injected liquid foaming
agent (L) within the tightly engaged dies (40, 41) under the
following conditions:
[0031] a) The air permeability of the slab foam wadding layer (2)
is set to be 0.2 cc/cm.sup.2/sec.,
[0032] b) The degree of foaming pressure is set to be approximately
0.1 kg, and
[0033] c) The thickness of the slab foam wadding layer (2) is 5
mm.
[0034] Note: As known in the art, the degree of foaming pressure
depends on an amount of liquid foaming agent to be injected in the
trim cove assembly with respect to an inner volume defined in the
dies (40) (41).
[0035] As a result thereof, there was produced a resulting headrest
body (P) as shown in FIG. 3, in which a mass of foam padding or
foam cushion member (B) created from the liquid foaming agent (L)
is filled within the trim cover assembly (T) together with the
headrest frame (C). It is therefore observed and appreciated
that:
[0036] (i) The liquid foaming agent (L) is impregnated evenly in
the slab foam wadding layer (2) at a proper ratio of impregnation,
i.e. approx. 2 mm, relative to a whole thickness, i.e. 5 mm, of
that slab foam wadding layer (2), and cured therein to form approx.
2 mm thickness of an impermeable film layer (20) between the top
cover layer (1) and a foam cushion member (B) being created from
the liquid foaming agent (L), as in FIG. 4. Accordingly, such film
layer (20) serves to enclose a whole inner space of trim cover
assembly (T) and prevent escape of air therethrough, thereby
allowing an increasing foamed mass of liquid foaming agent, or an
outwardly increasing foaming pressure, to be applied evenly to all
the inner walls of trim cover assembly (T) during foaming process,
so that the outer surfaces of trim cover assembly (T) are in an
optimum stretched state. In addition thereto, an outward pressure
given from the increased mass of foam cushion member (B) created
from the liquid foaming agent (L) effectively brings each of the
cover materials (A) or the trim cover assembly (T) to pressed
contact with the inner die surfaces of the dies (40, 41) in
conformity therewith. Thus, it is practically possible to attain a
neatly finished and desired outer appearance of resulting headrest
body (P) without any crease and slack portion therein.
[0037] Also, the liquid foaming agent (L) is impregnated and cured
in the sewn connection portions (A1), and particularly filing seam
or needle holes therealong (not shown), thereby insuring to prevent
leakage of the liquid foaming agent (L) itself from the seam or
needle holes.
[0038] In this context, experiments show that use of slab foam
wadding layer (2) with the air permeability of over 1
cc/cm.sup.2/sec. results in undesired penetration of liquid foaming
agent (L) past through that slab foam wadding layer (20) to reach
the top cover layer (1). In that instance, a substantive area of
the top cover layer (1) becomes hardened to lose its stretchable
property, as a result of which, the outer surfaces of trim cover
assembly (T) are not uniformly stretched, with a plenty of
objectionable creases and slack portions caused therein. On the
other hand, experiments show that use of slab foam wadding layer
(2) with the air permeability of less than 0.1 cc/cm.sup.2/sec.
results in reducing air escape therethrough and thus an excessive
exertion of foaming pressure upon the trim cover assembly (T) to
the degree of causing the liquid foaming agent (L) to leak
outwardly through the seam or needle holes of the sewn connection
portions (A1).
[0039] (ii) Even if an air is trapped in the boundary between the
liquid foaming agent (L) and slab foam wadding layer (2) during the
foaming process, the air permeability of top cover layer (1) and
the non-excessive impregnation of the liquid foaming agent (L) in
the slab foam wadding layer (2) are effective in not only forcing
such trapped air into the slab foam wadding layer (2), but also
causing the air to flow therethrough and escape through the
permeable top cover layer (1) to the outside of the trim cover
assembly (T). This prevents creation of any trapped air region in
local areas of trim cover assembly (T) which are adjacent to the
outer surfaces of the resultant headrest (P), thus avoiding such
unpleasant seating touch and problems as stated in the description
of prior art.
[0040] (iii) As stated above, the liquid foaming agent (L) is
impregnated in the slab foam wadding layer (2) at a small
proportion relative to the whole thickness of the latter (2).
Therefore, the liquid foaming agent (L) is not impregnated
outwardly through the slab foam wadding layer (2) and does not
reach the top cover layer (1), neither, so that the cured layer of
the foaming agent (L), i.e. the film (20), is not formed beneath
the top cover layer (1), thus giving an original soft cushiony
touch of the hardest body (P) to a passenger.
[0041] While having described the present invention, it should be
understood that the invention is not limited to the illustrated
embodiment, but other modification, replacement, and addition may
be applied thereto without departing from the scopes of the
appended claims.
* * * * *