U.S. patent number 3,751,111 [Application Number 05/227,870] was granted by the patent office on 1973-08-07 for variable density contour chair.
Invention is credited to H. Jack Becker, Glenn H. Johnson, Marvin A. Taylor.
United States Patent |
3,751,111 |
Taylor , et al. |
August 7, 1973 |
VARIABLE DENSITY CONTOUR CHAIR
Abstract
A chair includes a cushion of relatively low density flexible
material that captivates specially positioned blocks of relatively
high and intermediate density flexible material in a manner to
improve comfort and minimize certain discomforts of sitting. The
relatively high and intermediate density blocks are arranged in a
pattern to coincide with predetermined high and intermediate load
bearing regions determined from date derived from measuring a
backside area of a person or a group of people. The load is
distributed so that the stronger and more sensitive prone parts of
a person are subjected to proportionally greater and lesser amounts
of the overall load as compared with conventional cushions of
uniformly compressive material or layered materials.
Inventors: |
Taylor; Marvin A. (Santa
Monica, CA), Johnson; Glenn H. (Santa Monica, CA),
Becker; H. Jack (Los Angeles, CA) |
Family
ID: |
22854801 |
Appl.
No.: |
05/227,870 |
Filed: |
February 22, 1972 |
Current U.S.
Class: |
297/452.27;
297/452.37; 297/451.4; 297/DIG.1 |
Current CPC
Class: |
A47C
27/20 (20130101); A47C 31/126 (20130101); A47C
27/144 (20130101); A47C 3/12 (20130101); Y10S
297/01 (20130101) |
Current International
Class: |
A47C
31/12 (20060101); A47C 31/00 (20060101); A47C
3/12 (20060101); A47C 3/00 (20060101); A47c
007/02 (); A47c 001/12 () |
Field of
Search: |
;297/284,452-459,445
;5/345 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Nunberg; Casmir A.
Claims
What is claimed is:
1. A chair comprising:
a. a supporting shell;
b. a cushion constructed primarily from a matrix of relatively low
density flexible foam material and secured to the supporting shell,
the cushion having a relatively high load bearing region, a
relatively intermediate load bearing region and a relatively light
load bearing region;
c. a block of relatively high density flexible foam material
captivated by the relatively low density flexible foam material and
positioned within the relatively high load bearing region of the
cushion;
d. a block of relatively intermediate density flexible foam
material captivated by the relatively low density foam material and
positioned within the relatively intermediate load bearing region
of the cushion, the relatively low density flexible foam material
being distributed to occupy the relatively light load bearing
region, the blocks of relatively high and intermediate density
flexible foam material being specially shaped to fully occupy the
relatively high and intermediate load bearing regions respectively,
and oriented in side by side and generally co-planar
relationship.
2. The structure according to claim 1, wherein the cushion
includes:
an upper cushion portion having a single block of high density foam
material and a single block of intermediate density flexible foam
material;
a lower cushion portion having at least dual blocks of high density
foam material and dual blocks of intermediate density foam material
arranged adjacent corresponding dual blocks of high density
flexible foam material.
3. The structure according to claim 2, wherein;
the dual blocks of relatively intermediate density flexible foam
material are formed with recesses configured to receive
corresponding dual blocks of high density flexible foam
material.
4. The structure according to claim 2, wherein;
the upper cushion single block of intermediate density flexible
foam material has a cut-out area configured to receive the single
block high density flexible foam material.
5. The structure according to claim 2, wherein;
the upper cushion single block of intermediate density flexible
foam material has a cut-out area configured to receive the single
block high density flexible foam material;
the dual blocks of relatively intermediate density flexible foam
material are formed with recesses configured to receive
corresponding dual blocks of high density flexible foam
material.
6. The structure according to claim 1, wherein;
the flexible foam material is a type of polyurethane foam with
self-skinning properties.
7. The structure according to claim 6, wherein;
the low, intermediate and high density polyurethane foam have
densities of approximately 1 1/2 pounds per cubic foot, 4 pounds
per cubic foot and 6 pounds per cubic foot respectively.
Description
BACKGROUND OF THE INVENTION
This invention generally relates to chairs and more specifically to
a contour chair having sections of different densities arranged in
a special pattern to alleviate annoying and harmful pressures.
The concept of contouring chairs in order to make them more
comfortable and stylish is well known in the furniture trade. These
chairs ordinarily include a supporting framework or shell curved to
accommodate the general configuration of a person's body and a
plurality of separate or linked cushions e.g.; see U.S. Pat. Nos.
3,073,649 to De Montfort granted Jan. 15, 1963 and 3,370,885 to
Gale granted Feb. 27, 1968.
Moreover the concept of employing materials of different densities
in the construction of chairs is known, e.g.; see U.S. Pat. No.
3,000,020 to Lombard et al. granted Sept. 19, 1961, 3,118,153 to
Hood granted Jan. 21, 1964 and 3,175,863 to Hood granted Mar. 30,
1965. The construction materials of different densities are layered
or stacked in a particular sequence for comfort, shock-absorbing or
appearance purposes.
Both common sense and medical studies indicate that certain parts
of a persons's body are best suited to accept pressure and absorb
resulting stress. Conventional chairs are constructed to spread the
pressures around in a uniform manner which has the adverse result
of subjecting relatively sensitive and poor load bearing portions
of a person to disproportionate and excessive strain. Such
concentrations in the sensitive areas will eventually result in
fatigue, discomfort and possible physical harm.
A primary aim of this invention is to provide a chair with flexible
sections of different density and load bearing characteristics
arranged in a special predetermined pattern in order to enable the
overall load to be distributed so that a greater share of the load
is borne by the superior load bearing portions of the person and
therefore the weaker portions of the person are subjected to a
lesser amount of the load.
SUMMARY OF THE INVENTION
Briefly stated this invention comprehends a variable density
contour chair having a supporting shell and a cushion secured to
the supporting shell.
The cushion is constructed primarily from a matrix of relatively
low density flexible foam material and has a relatively high load
bearing region, a relatively intermediate load bearing region and a
relatively light load bearing region.
A block of relatively high density flexible foam material is
captivated by the low density flexible foam material and positioned
within the relatively high load bearing region of the cushion. A
block of relatively intermediate flexible foam material is likewise
captivated by the relatively low density flexible foam material and
is positioned so as to occupy the space constituted by the
relatively intermediate load bearing region of the cushion.
The blocks of relatively high and intermediate density flexible
foam material are specially shaped to fully occupy the relatively
high and intermediate regions and preferably are oriented in
side-by-side generally co-planar relationship.
The cushion has an upper cushion portion with at least a single
block of relatively high density foam material and a single block
of relatively intermediate density flexible foam material. The
cushion also has a lower cushion portion including at least dual
blocks of high density foam material and corresponding dual blocks
of relatively intermediate density flexible foam material.
In carrying out the process of this invention data is gathered from
measuring the physical shape of a backside area of a person or
persons. A chart is prepared from this data and is divided into
relatively high load bearing region, a relatively intermediate load
bearing region and a relatively low load bearing region. Blocks are
fabricated from relatively high density flexible foam material and
intermediate density flexible foam material. The blocks of high and
intermediate density are positioned in the mold or otherwise
arranged in a pattern so that they are located in the high load
bearing region and the intermediate load bearing region. A
relatively low density flexible foam material is then flowed around
the blocks in order to captivate them and fill in the specified
contour which constitutes a chair for accommodating a particular
person.
BRIEF DESCRIPTION OF THE DRAWINGS
The numerous benefits and unique aspects of the present invention
will be fully understood when the following detailed description is
studied in conjunction with the drawings in which:
FIG. 1 is a perspective, fragmentary and sectional view of a
contour chair constructed in accordance with this invention showing
variable density sections arranged in a predetermined position or
area;
FIG. 2 is a perspective, partially sectional and partially exploded
view showing some variable density sections positioned in a mold
prior to being confined and permanently set in place; and,
FIG. 3 is a schematic depiction or chart pattern showing a pressure
distribution diagram in the lower portion of the chart relating to
a particular but hypothetical person and a density diagram on the
upper portion of the chart.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings for a full description of this
invention, FIG. 1 shows a variable density contour chair 10 having
a supporting shell 11 that may be fabricated from any durable
suitable material such as fibreglass, metal or wood. The supporting
shell 11 has a head rest section 12, an intermediate backrest 13, a
seating section 14 and a pedestal 15. The opposing sides of shell
11 include upright walls 16 shaped to form arm rests 17.
The chair 10 embodies a cushion 20 having an upper cushion portion
21 and a lower cushion portion 22. The cushion 20 has an outer or
exposed skin 24 and a lower or concealed surface 23 that is
attached by cement, bonding compound or other securement means
directly to shell 11. A longitudinal cross sectional view of
cushion 20 is taken to one side of the longitudinal center line 18
of chair 10.
An enveloping mass or matrix 30 of relatively low density flexible
foam material constitutes the general body of cushion 20. Matrix 30
surrounds and confines a series of relatively intermediate density
and also high density blocks of flexible foam material. The
relatively high density blocks 31 and 32 are located within the
upper cushion portion 21 and lower cushion portion 22 respectively.
The medium density blocks 33, 34 and 35 are located adjacent the
shell head rest section 12, the backrest section 13 and seating
section 14, respectively and surround the high density blocks. As
shall be fully explained the higher density blocks are judiciously
and precisely placed within regions of cushion 20 where a person
would require increased or additional support.
Referring now primarily to FIG. 2 another relatively high density
block 36 is shown aligned symmetrically with block 32. Similarly,
additional intermediate density blocks 37 and 38 are shown disposed
symmetrically relative to blocks 33 and 35 respectively. An
important step in the procedure of fabricating chair 10 involves
precisely arranging the blocks in a predetermined pattern within a
mold 40. The blocks are laid in this predetermined pattern within a
cavity 42 of a lower mold section 41.
In order to carefully conform the external shape of cushion 20 to
the physical shape of a particular hypothetical person a plaster
cast 45 may be constructed from an impression previously made from
a particular back side area of the person. The cast 45 is shown
formed with the person's simulated profile 44. A cross sectional
shape of the profile 44 shows a simulated head 46, upper back 47,
lower back 48, posterior 49 and upper leg 50 of the hypothetical
person.
Alternatively the contour of the person's body may be formed during
the flowing of foam material by way of seating the individual
person on a contour liner. The cushion formed is then only suitable
for that person whose impression was made.
The particular flexible foam material from which the low density
flexible foam material, medium density flexible foam material and
high density foam material are constructed can be any suitable
plastic or rubber. The material may be a self-skinning type of
polyurethane which has relatively superior physical properties of
excellent resistance to abrasion, good temperature stability, high
tensile strength and good insulation capabilities. When molding
articles from this material, the polyurethane foam develops a
permanent skin in one operation thereby eliminating the need of
multiple steps and laminating procedures. When this type of
polyurethane foam is poured in place within mold 40 and cured the
resulting article or cushion 20 has an integral exposed skin 24 and
a concealed surface 23 permanently adhered to shell 11 of chair
10.
The chair 10 of this invention is constructed to alleviate strain
and minimize fatigue by organizing the chair components in a
special pattern to distribute the pressure. The cushion 20 and
chair 10 can be custom designed to accommodate the particular
requirements of a single person or can be designed to accommodate
many people within a general range or class.
Body sensitivity to pressure varies from being relatively dull at
some body portions to relatively acute at other body portions. The
cushion 20 is constructed to distribute pressure in a manner
generally inversely proportional to pressure sensitivity, i.e.;
greater pressure on parts of the body less sensitive to pressure
and less pressure on parts of the body more sensitive to pressure.
FIG. 3 will be described in connection with explaining how this
invention may be used and operated.
OPERATION
Keeping the above information in mind it can be understood how the
previously described disadvantages of conventional contour chairs
and the like are overcome or substantially eliminated by this
invention.
Prior to actually constructing a cushion 20 distribution
information relative to a certain person or a class of persons is
developed and the developed pressure pattern is represented on the
lower half of a special chart 55 shown in FIG. 3. The pressure
distribution information can be derived by using electrical
pressure indicating devices, pressure sensitive paper, a network of
strain gauges or any other conventional device. This data is then
represented on the lower half of chart 55, captioned "pressure
diagram," in the form of equal pressure curves or isobars. For
example, isobars 56 for the back portion of a person shows pressure
increasing inwardly to a predetermined maximal pressure isobar 57.
In a similar manner isobars 58 for the posterior portion increase
across a gradient of pressure towards a predetermined maximal
isobar 59.
In various individuals pressure distribution will reach maximal
pressure over an area dispersed from the ischial bone or skeleton
through the muscle area. In other individuals with less muscle
structure such as invalids or dehabilitated persons, the pressure
approaches maximal at points under the ischial tuberosity.
The pressure distribution curves indicated on the "pressure
diagram" of chart 55 are interpreted and used for dictating whether
light density, intermediate density or high density flexible foam
material will be utilized in certain regions of the cushion 20.
It will be appreciated that for pressure regions greater than the
critical pressures indicated by isobars 57 and 59, relatively high
density material 31 a and 32 a will be used. For regions between
predetermined minimal isobars and associated maximal isobars the
intermediate density material 33 a, 34 a and 35 a will be used. The
numerals shown in connection with the upper part of chart 55
captioned "density diagram" correspond with the numerals of FIG. 1
and FIG. 2. When the general outlines for the blocks of high
density and intermediate density material are determined then the
individual blocks are cut out or otherwise formed into shape for
subsequent placement in mold 40 and eventual incorporation in the
cushion 20. By way of example the person for whom variable density
contour chair 10 is being constructed may be a dehabilitated person
requiring a chair with certain physical measurements and contoured
impressions. By way of this invention the support points about
which the isobars extend or radiate for certain distances can be
determined. Pressure point data can be provided by way of
instrumented chairs equipped with potentiometers and gauges for
example so that eventually a "pressure diagram" is shown in the
lower half of FIG. 3 may be developed. Also anthropomorphic data
for persons having a general type of stature may be used.
As previously indicated the chair 10 may be completed by having the
particular person positioned on a liner located in the mold 40.
From the foregoing it will be evident that the present invention
has provided a variable density contour chair in which all of the
various advantages are fully realized.
* * * * *