Note: Descriptions are shown in the official language in which they were submitted.
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HEADREST FOR AUTOMOTIVE SEAT
The present invention relates to a headrest for use on an automotive seat.
In particular, this invention is directed to a headrest wherein a headrest
frame is inserted into a three-dimensional trim cover assembly of a given
headrest shape, through an opening defined therein. After insertion, a liquid
foaming base material is injected in the trim cover assembly, and the
subsequent foaming integrally joins the frame and trim cover assembly
together. More particularly, the present invention is directed to a donut-like
or
generally annular headrest having a through-hole therein, which headrest is
formed by a foaming process of this kind.
In a process for forming a donut-like or annular headrest for use on an
automotive seat, there is usually found a method that requires using a bent
headrest frame with headrest stays) and inserting it into and along the
annular
hollow inside of a preformed three-dimensional donut-like trim cover assembly.
Subsequent thereto, a liquid foaming base material is injected into the trim
cover assembly and cured therein with the headrest frame in place. A resulting
foamed donut-like headrest unit is obtained, with the headrest stays)
projected
therefrom.
This process, however, has encountered a technical difficulty in terms of
how the headrest frame can be easily placed in the preformed donut-like trim
cover assembly for the subsequent foaming process. Some solutions to this
problem have been proposed, for example, those disclosed in the Japanese laid-
open patent publication Nos. 62-257818 and 9-271425, and also in the Japanese
granted Patent Pub. No. 4-401818. These documents commonly suggest that a
generally inverted U-shaped headrest frame with headrest stays be inserted in
the preformed donut-like trim cover assembly, and then, a connecting frame be
connected between two side frame sections of such headrest frame, to thereby
provide an annular frame portion extending in and along the donut-like trim
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cover assembly. After this procedure, a foaming is affected to create a foam
padding integral with the frames and trim cover assembly, so that a donut-like
headrest is obtained.
Such solution has been found defective in that the connecting frame
cannot be quickly and precisely assembled with the headrest frame because a
worker can hardly see the connecting point between the connecting and
headrest frames which are both located in the trim cover assembly. He must
manage to connect together these two frames within the trim cover assembly,
feeling them with his hands.
To overcome this drawback, it has been suggested that the connecting
frame be connected with the headrest frame, outside of the trim cover
assembly.
See for example Japanese granted U.M. Pub. No. 7-31724. According to this
prior art, a plate-like connecting frame is provided, which has a slit formed
therein. During assembly, a generally U-shaped headrest frame is inserted into
an opening of a donut-like trim cover assembly and placed in the trim cover
assembly through that opening. Two headrest stay sections of the frame project
outwardly therefrom. Thereafter, the plate-like connecting frame is connected
between the two projecting headrest stay sections, while the ends of the
foregoing opening of trim cover assembly are inserted into and through the
slit
of the connecting frame. In this way, the connecting frame can easily be
accessed and connected to the headrest frame, externally of the trim cover
assembly, in order to provide an annular frame work in conformity with the
donut-like trim cover assembly and also close the opening of the same trim
cover assembly.
However, in this prior art, the slit of the connecting frame is formed
rather narrow with a view to preventing leakage of a liquid foaming base
material from between the slit and the ends of the aforesaid opening. As a
result, it is troublesome and time-consuming for a worker to squeeze and
insert
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the ends of the opening into such a narrow slit during assembly. Further, this
sealing is rather rough, so that in the foaming process, a liquid foaming base
material injected in the trim cover assembly will invade into non-tight spots
between the connecting frame and ends of the opening, and result in creating
objectionable uneven or irregular spots in the outer surface of the resulting
headrest after the foaming process. This impairs the aesthetic appearance of
the
headrest.
The present invention provides an improved donut-like headrest for use
on an automotive seat, which can be easily and quickly formed using a foaming
process, while preventing leakage of a liquid foaming base material therefrom.
The headrest in accordance with the present invention includes a
generally annular three-dimensional trim cover assembly having an annular
inner hollow therein and an opening formed at one side thereof, wherein the
opening is defined by an edge of the cover assembly. The trim cover assembly
is made of at least a two layer lamination structure comprising a top cover
layer
and an elastic foam wadding layer. The headrest also includes a generally "U"
shaped headrest frame having a pair of stay portions for mounting on the
automotive seat.
The generally "U" shaped headrest frame means is disposed in and along
the annular inner hollow of the three-dimensional trim cover assembly, with
the
pair of stay portions thereof projecting from the opening of the trim cover
assembly. A sealing and connecting frame connects the stay portions and closes
and seals the opening. The sealing and connecting frame has a groove in which
the edge of the cover assembly fits and is engaged. The sealing and connecting
frame is provided between the stay portions.
A foam padding is formed within the three-dimensional trim cover
assembly using a foaming process such that a liquid foaming base material is
injected and cured in the trim cover assembly together with a part of the
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generally "U" shaped headrest frame. The liquid foaming base material is
prevented by the sealing and connecting frame from leaking through the
opening during the foaming process.
Accordingly, the edge of the opening of the trim cover assembly is
engaged in the groove of the sealing and connecting frame means so as to
provide a dual sealing effect. The opening edge is biased into contact with
the
bottom of the groove due to the elastic recoiling property of the foam wadding
layer of the trim cover assembly. Further, the same opening edge is biased to
contact with one wall of the groove by an increased mass of the foam cushion
padding that has been formed by the foaming process. Thus, during the foaming
process, such simple dual sealing structure of the sealing and connecting
frame
means completely prevents leakage of the liquid foaming base material through
the opening. Moreover, a worker can easily connect the sealing and connecting
frame to the stay portions of the headrest frame from the outside, while
simply
fitting the edge of the opening of the trim cover assembly in the groove of
the
sealing and connecting frame means.
Preferably, a pair of holes are formed in the sealing and connecting
frame so that the foregoing pair of stay portions of the headrest frame pass
through the two holes, thereby easily connecting the sealing and connecting
frame with the headrest frame at a predetermined point, providing a robust
frame structure. Preferably, an elastic tubular sealing member is provided on
each of the two stay portions, so that the sealing and connecting frame is
secured on the tubular sealing members and any minute clearance therebetween
is sealed against any possible leakage of a liquid base foaming material
therethrough during the foaming process.
Other features and advantages of the headrest will become apparent from
a reading of the detailed description hereinafter, with reference to the
annexed
drawings.
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In the drawings,
Fig. 1 is an exploded schematic perspective view showing an incomplete
headrest unit to be subjected to a foaming process in accordance with the
present invention;
Fig. 2 is a front view of a sealing and connecting frame used in the
present invention;
Fig. 3 is a sectional view taken along the line III-III in Fig. 2;
Fig. 4 is a diagram to show one process of assembling the incomplete
headrest unit, in which the sealing and connecting frame is about to be
connected with two stay portions of the headrest frame;
Fig. 5 is a perspective view of a resultant incomplete headrest unit;
Fig. 6 is a sectional view of another embodiment of the sealing and
connecting frame;
Fig. 7 is a schematic sectional view showing an incomplete headrest unit
placed in a foaming die device, and also showing how foaming is carried out;
Fig. 8 is a schematic longitudinally sectional view of a resultant foamed
headrest wherein the first type of sealing and connecting frame is used; and
Fig. 9 is a schematic longitudinally sectional view of a resultant foamed
headrest wherein the other type of sealing and connecting frame is used.
Referring to Figs. 1 through 9, there are illustrated preferred
embodiments of headrests constructed in accordance with the present invention.
This type of headrest has a generally donut-like or annular configuration and
is
for use on an automotive seat (not shown).
Fig. 1 shows an incomplete headrest unit, generally designated by (HU),
which is the unit to be subjected to a foaming process described herein. As
illustrated, the unit (HU) basically comprises a preformed donut-like or
generally annular trim cover assembly 1 having an elongate opening 10, a
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generally inverted U-shaped headrest frame provided with a locating means (at
21A) and a plate-like sealing and connecting frame 3.
As can be seen from Fig. 1 in conjunction with Figs. 7, 8 and 9, the trim
cover assembly 1 itself is preferably an at least two layer lamination
structure
comprising a top cover layer la and a wadding layer lb of slab urethane foam
material so as to have a certain elastic yet rigid property, an important
factor for
the elongated opening 10 as shown below. The top cover layer 1 a can be
formed from a woven or non-woven fabric material or a synthetic resin leather
material. The trim cover assembly 1 can be preformed by sewing together
several separate cover sections of such two-layer lamination structure into
the
illustrated three-dimensional donut or annular shape having a through-hole lA
formed centrally therein. In particular, the bottom wall 1B of this trim cover
assembly 1 is formed with the foregoing elongate opening 10 and also with an
injection hole 12. The injection hole 12 is adapted for allowing insertion of
an
injection nozzle (see 12 in Fig. 7) thereinto so that a liquid foaming base
material may be injected via the nozzle into the trim cover assembly 1 in a
subsequent foaming process. In the illustrated mode, the elongated opening 10
is formed to have a pair of longitudinal edges 10A, l OB and a pair of
generally
curved side edges l OR such as to provide a proper size of opening sufficient
for
the sealing and connecting frame 3 to be passed therethrough and smoothly
placed in and along the annular inner hollow of trim cover assembly 1.
The sealing and connecting frame 3 has an elongate plate configuration,
a pair of spaced-apart holes 30 formed therein, and a peripheral engagement
groove 31 formed in and along the periphery thereof. As will be apparent, the
pair of holes 30 are so adapted that two stay portions 21 of the headrest
frame 2
can be passed therethrough, respectively. The two holes 30 are both slightly
greater in diameter than the respective stay portions 21, since this allows
smooth passing of the sealing and connecting frame 3 along the two stay
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portions 21 until the frame 3 is frictionally retained on two tubular sealing
members 2A, as explained below. As best shown in Figs. 2 and 3, in the sealing
and connecting frame 3, the peripheral engagement groove 31 is a generally
rectangular recess which conforms generally in shape to the likewise
rectangular contour of the edges 10A, l OB, l OR of elongate opening 10. The
groove 31 therefore has a pair of longitudinal bottoms 31 B for receipt of
respective longitudinal edges 10A, lOB of elongate openings 10, and a pair of
generally curved side bottoms 31A, 31A for receipt of respective side edges
l OR of the same opening 10. Outward and inward walls 32, 33 of the frame 3
are located on the opposite sides of these bottoms 31A, 31B, as can be seen
from Fig. 3. It is important that the width of the groove 31 be equal to or
slightly greater than the total thickness of the two-layer lamination la, lb
of
trim cover assembly 1, and that both longitudinal and side bottoms 31B, 31A of
the groove 31 be slightly greater in size than the size of elongate opening
10,
for sealing purposes related to the subsequent foaming process. Preferably,
the
sealing and connecting frame 3 is formed from a rigid and hard synthetic resin
material, such as polypropylene.
The headrest frame 2, in accordance with the present invention, is
formed by bending a metallic tube or rod into a generally "U" shaped
configuration, the rod having a generally semi-circular head support portion
20
and a pair of stay portions 21 to be mounted on a seat back of an automotive
seat (not shown). Each of the two stay portions 21 is provided with a pair of
location projections 21A as a means for limiting and locating the sealing and
connecting frame 3 at a given position relative to the elongate opening 10 of
the
trim cover assembly 1. Thus, a worker can easily locate the frame 3 at the
stay
portions 21 of headrest frame 2 and also determine an appropriate proportion
of
the sem-circular head support portion 20 to be located within the annular
inner
hollow of the donut-like trim cover assembly 1. At the same time, the worker
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can directly engage the edges 10A, l OB, l OR of opening 10 in and along the
engagement groove 31 of frame 3, without taking into account the proportion of
the stay portions 21 to the semi-circular head support portion 20 in relation
to
the trim cover assembly 1. For that purpose, both pairs of location
projections
21A, each pair extending integrally from opposite sides of one of the stay
portions 21, are disposed at a predetermined point on the stay portions 21
near
to the juncture between the generally semi-circular head support portion 20
and
stay sections 21.
The pair of tubular sealing members 2A are secured about the pair of
stay sections 21 of headrest frame 2 and are adapted for tight engagement in
the
respective two holes 30 of the sealing and connecting frame 3. The purpose of
the sealing members 2A is not only to retain the sealing and connecting frame
3
at a predetermined position set by the location projections 21A upon the two
stay sections 21 but also to seal a minute clearance between the stay section
21
and the hole 30 and thus prevent possible leakage of a liquid base foaming
material therethrough. These tubular sealing members 2A can preferably be
formed from a rubber tubular material or other suitable elastic material such
as
an elastic synthetic resin material, so that each will strongly stick to and
on the
stay portion 21. As shown in Fig. 1, each of the sealing members 2A is secured
on the stay portion 21 at a point adjoining the location projections 21A, so
that
the sealing and connecting frame 3 can be secured by these sealing members at
a predetermined point where the edge of elongate hole 10 of trim cover
assembly 1 can easily and quickly be engaged in and along the groove 31 of
frame 3.
The process for forming a donut-like headrest, using the above-described
basic constituent elements, will now be described.
In a first step, the headrest frame 2 is inserted via the elongated opening
10 into the donut-like trim cover assembly 1 by first inserting one of the two
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stay portions 21 in and along the annular inner hollow of trim cover assembly
1. The headrest frame 2 is moved around and within the trim cover assembly 1.
Then, the whole of the headrest frame 2 is adjustingly placed in position
within
the trim cover assembly 2, with both stay portions 21 projecting outwardly
from the elongate opening 10, as can be seen in Fig. 4. At this point, a
worker
can easily find where to locate the headrest frame 2 and its two stay portions
21
relative to the opening 10, because he or she can see both location
projections
21A and tubular sealing members 2A at the opening 10. Then, by letting the
two stay portions 21 pass through the respective two holes 30, the worker can
slide the sealing and connecting frame 3 on and along the two stay portions 21
until both holes 30 ride on and about the two sealing tubular members 2A,
respectively. The worker continues to forcibly slide the sealing and
connecting
frame 3 along until the tubular sealing members 2A are completely located in
and secured in the holes 30 and the inward wall 33 of the frame 3 contacts the
location projections 21A. In this way, the sealing and connecting frame 3 is
now set in position between the two stay portions 21 of headrest frame 2.
Then,
a worker widens the elongate opening 10 with respect to the sealing and
connecting frame 3 and engages its edges 10A, IOB, lOR in and along the
peripheral engagement groove 31 of the frame 3, whereupon an incomplete
headrest unit (HU) is assembled as shown in Fig. 5.
Next, as illustrated in Fig. 7, this incomplete headrest unit (HU) is
placed between upper and lower dies (UD) (LD) of an ordinary known type of
foaming die device, which has die surfaces generally contoured along the outer
shape of the above-assembled incomplete headrest unit (HU). Thereafter, an
injection nozzle (N) is inserted into the inside trim cover assembly 1 via the
injection hole 12 , and a liquid foaming base material 4L is injected from the
nozzle N thereinto, so that an appropriate amount of the base material 4L is
contained in the trim cover assembly 1. The liquid foaming base material 4L is
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then cured to subject the whole incomplete headrest unit (HU) to foaming,
whereby a foam padding 4 is formed within the trim cover assembly. This
padding is integral with the headrest frame 2 and sealing and connecting frame
3, as shown in Figs. 8 and 9. Thus, a donut-like headrest (HR) is produced.
During the foaming process, the whole of edges 10A, lOB and l OR of elongate
opening 10, due to its elastic repercussive property originating from the foam
wadding layer lb of the trim cover assembly 1, are driven tight against and
along the groove bottoms 31A, 31B of the sealing and connecting frame 3. In
addition, the increasing elastic mass of foamed base material 4L presses
against
the peripheral area around opening 10 causing this area to contact closely the
outward wall 32. In this way, a dual sealing effect is provided between the
frame 3 and opening 10 to completely prevent leakage of the liquid foaming
base material 4L.
Fig. 6 shows an alternative type of sealing and connecting frame 3, the
use of which is within the scope of the present invention. An inward wall 33
is
formed which is small relative to the outward wall 32 by simply cutting off
the
peripheral end region of the corresponding inward wall of the above-described
first type of frame 3. This arrangement facilitates the ease with which a
worker
can engage the opening edges 10A, l OB, l OR of trim cover assembly 1 in and
along the engagement groove 31 of the sealing and connecting frame 3. He or
she does not need to widen the opening 10 as much as with the first type
having
the same size of outward and inward walls 33, 32. Subsequent to placement of
this second type of frame, the same foaming process is affected, using the
same
foaming die device shown in Fig. 7. Fig. 9 shows a resultant donut-like
headrest
(HR) in which such second type of sealing and connecting frame 3 is used. In
this case, the same dual sealing effect is realized between the frame 3 and
opening 10, thereby preventing leakage of the liquid foaming base material 4L.
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Accordingly, in accordance with the present invention, both frames 2
and 3 can be quickly assembled together at a given connecting point (at 21A),
without any care about proportion between the generally circular head support
portion 20 and the two stay portions 21 in relation to the trim cover assembly
1,
and the sealing and connecting frame 3 can be easily mounted in the opening 10
to close the latter in an optimum sealing fashion effective at the subsequent
foaming process. Further, the sealing and connecting frame 3 is connected with
the headrest 2 via the two holes 30, which advantageously allows a worker to
assure positive connection between the two frames 3, 2 with much ease and
rapidity. This arrangement also provides a reinforcement for the headrest
frame
2. Moreover, in contrast to the hitherto headrest framework of this sort, the
connecting frame 3 her se has the outward wall 32 exposed externally of the
trim cover assembly 1, and therefore, this wall 32 serves to finally stop
leakage
of liquid foaming base material 4L and to cover the peripheral region of the
opening 10 in which such leakage might occur. Hence the wall 32 conceals any
uneven spots of leaked cured foaming material that have been created after the
foaming process.
It should be understood that the invention is not limited to the illustrated
and described embodiments but other modifications, replacements and
additions may be used without departing from the scope of this invention and
appended claims.
