U.S. patent number 3,669,499 [Application Number 05/102,592] was granted by the patent office on 1972-06-13 for chair.
This patent grant is currently assigned to Steelcase Inc.. Invention is credited to Stephen B. Kolk, Frans Semplonius.
United States Patent |
3,669,499 |
Semplonius , et al. |
June 13, 1972 |
CHAIR
Abstract
The specification discloses a chair whose structural strength is
derived from a molded, high-impact polystyrene structural shell.
The face of this shell is covered with suitable cushioning and
upholstery and arms may be provided if desired. This structural
shell is then joined to a decorative, molded polypropylene trim
shell which covers the rear of the structural shell and which
includes a recessed portion to accommodate the seat supporting pan
of a chair base which is secured to the structural shell, through
the trim shell.
Inventors: |
Semplonius; Frans (Kentwood,
MI), Kolk; Stephen B. (Grand Rapids, MI) |
Assignee: |
Steelcase Inc. (Grand Rapids,
MI)
|
Family
ID: |
41127549 |
Appl.
No.: |
05/102,592 |
Filed: |
December 30, 1970 |
Current U.S.
Class: |
297/452.14;
297/445.1; 297/440.2; 297/452.38 |
Current CPC
Class: |
A47C
31/00 (20130101); A47C 5/06 (20130101); A47C
5/12 (20130101); A47C 3/12 (20130101); A47C
7/18 (20130101) |
Current International
Class: |
A47C
5/00 (20060101); A47C 5/12 (20060101); A47C
7/18 (20060101); A47C 31/00 (20060101); A47C
3/12 (20060101); A47C 3/00 (20060101); A47c
007/00 (); A47c 007/02 () |
Field of
Search: |
;297/416,420,421,445,443,451,452,458,460 ;5/356 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Nunberg; Casmir A.
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. A chair comprising a load bearing structural shell with integral
seat and back; means for covering the front face of said structural
shell; a molded, plastic non-load bearing trim shell having a
decorative exterior appearance, integral seat and back covering
portions for covering generally the rear surfaces of said
structural shell, and sufficient thickness and rigidity to hold a
desired design configuration; said trim shell being secured to said
structural shell and being positioned to cover the rear of said
structural shell to thereby give the chair a decorative exterior
appearance.
2. The chair of claim 1 which comprises: a chair base having a seat
supporting pan which is positioned within an upwardly projecting
recess in said seat covering portion of said trim shell; means
securing said supporting pan to said structural shell through said
trim shell.
3. The chair of claim 2 in which the bottom of said structural
shell comprises a downwardly projecting, generally rectangular rib
to provide said structural shell with increased thickness and
rigidity in the area of connection to said seat supporting pan.
4. The chair of claim 1 which comprises a continuous arm secured at
either side thereof; one end of each arm extending around to the
rear of said structural shell back and being secured thereto and
the other end extending around to the rear of said structural shell
seat and being secured thereto; said seat and said back each
including a recessed channel in the peripheral edge portion of said
structural shell for accommodating the thickness of said arm such
that said trim shell can be snugly secured to the rear of said
structural shell and thereby cover the connection of said arms to
said structural shell.
5. The chair of claim 1 in which said means for covering the face
of said structural shell comprises: cushioning secured to the face
of said structural shell; upholstery covering said cushioning and
extending around the peripheral edge of said shell to the rear
thereof; said upholstery being secured at its perimeter to the rear
of said structural shell, and being hidden from view at its
perimeter by said trim shell.
6. The chair of claim 5 which comprises: a continuous layer of soft
padding material covering said cushioning material and being
covered by said upholstery and extending around the peripheral edge
of said structural shell, beneath said upholstery, and being
secured to the rear of said structural shell along with said
upholstery.
7. The chair of claim 5 in which said structural shell comprises: a
plurality of holes therethrough along the junction between said
seat and back; said upholstery being tufted along the junction
between the seat and back by means of threads sewn thereto and
being pulled through said plurality of holes and stapled to the
rear of said structural shell, hidden from view by said trim
shell.
8. The chair of claim 1 in which said structural shell comprises a
plurality of integral, reinforcing ribs extending down said back on
the rear side thereof and around to the bottom of said seat.
9. The chair of claim 5 in which said cushioning comprises: a first
cushion being applied to the face of said back in the lumbar
supporting region thereof; a second cushion being applied to the
face of said back in the shoulder supporting region thereof; said
first cushion being of heavier density than said second cushion in
order to provide greater support to the lumbar region of a person's
back.
10. The chair of claim 1 in which the peripheral edge of said trim
shell is covered by an elongated bumper strip to provide edge
protection and to fill any slight gaps between said peripheral edge
and said structural shell.
11. A chair comprising: a molded, high impact polystyrene
structural shell having sufficient thickness to provide an
integral, load bearing seat and back; means for covering the front
face of said shell; a molded, decorative polypropylene non-load
bearing trim shell for covering the rear surfaces of said
structural shell, the thickness of said trim shell being sufficient
to give it enough rigidity to hold a desired design configuration;
means for securing said trim shell to said structural shell whereby
the exterior of said chair is given a decorative appearance.
12. The chair of claim 11 in which said structural shell comprises
integral reinforcing ribs to give it added rigidity in
strength.
13. The chair of claim 1 with said trim shell being rigidly secured
to the back and to the seat of said structural shell to increase
the rigidity thereof.
14. The chair of claim 4 in which said arm comprises: a metal
support rod defining the general configuration of said arm and
including a first end portion bent inwardly from the generally
vertical plane of the arm to wrap around the underside of said
structural shell seat and a second end portion bent inwardly from
said generally vertical plane to wrap around the rear of said
structural shell back; said first and second end portions being
secured to said structural shell; a decorative trim member having a
channel on the underside thereof for receiving said metal support
rod, except for said first and second end portions; means securing
said trim member to said support rod with said support rod within
said channel.
15. The chair of claim 1 in which an arm is secured to either side
thereof, said arm comprising: a metal support rod defining the
general configuration of said arm and including a first end portion
bent inwardly from the generally vertical plane of the arm to wrap
around the underside of said structural shell seat and a second end
portion bent inwardly from said generally vertical plane to wrap
around the rear of said structural shell back; said first and
second end portions being secured to said structural shell; a
decorative trim member having a channel on the underside thereof
for receiving said metal support rod, except for said first and
second end portions; means securing said trim member to said
support rod with said support rod within said channel.
16. A chair comprising: an inner shell with a seat and a back;
means for covering the face of said inner shell; an outer shell
having seat and back covering portions; said outer shell being
secured to said inner shell and being positioned to cover the rear
of said inner shell; a continuous arm secured at either side of
said chair; one end of each arm extending around to the rear
surface of said inner shell back and being secured thereto and the
other end extending around to the under surface of said inner shell
seat and being secured thereto; said seat and said back each
including a recessed channel in the peripheral edge portion of said
inner shell for accommodating the thickness of said arm such that
said outer shell can be snugly secured to the rear of said inner
shell and thereby cover the connection of said arms to said inner
shell.
17. The chair of claim 16 in which said arm comprises: a metal
support rod defining the general configuration of said arm and
including a first end portion bent inwardly from the generally
vertical plane of the arm to wrap around the underside of said
inner shell seat and a second end portion bent inwardly from said
generally vertical plane to wrap around the rear of said inner
shell back; said first and second end portions being secured to
said inner shell; a decorative trim member having a channel on the
underside thereof for receiving said metal support rod, except for
said first and second end portions; means securing said trim member
to said support rod with said support rod within said channel.
18. The chair of claim 17 in which said inner shell comprises a
structural load bearing shell and said outer shell comprises a
molded, plastic non-load bearing trim shell having a decorative
exterior appearance and sufficient thickness and rigidity to hold a
desired design configuration.
Description
BACKGROUND
The primary objectives of chair design are to achieve both beauty
and substantial strength. Unfortunately, these objectives are not
necessarily compatible. Accordingly, the more durable chairs tend
to have conventional lines necessitated by the emphasis on
structural strength. Molded, reinforced plastic chairs are also
limited in design potential by the structural necessities of the
chair, such as the necessity of conforming to back curvature.
Furthermore, the exterior appearance of reinforced plastics renders
it unacceptable for many design purposes.
BRIEF DESCRIPTION OF INVENTION
The present invention provides a chair having a load bearing
structural shell with integral seat and back. Means are provided
for covering the face of said shell to give the face a decorative
appearance. A molded, plastic trim shell having a decorative
exterior appearance and having integral seat and back covering
portions is secured to the structural shell in such a manner that
the rear of the structural shell is covered by the trim shell in
order to give the chair a decorative exterior appearance.
Thus, the teachings of this invention contribute substantially to
improve the compatibility of the design and structural objectives
of chair engineering. The task of engineering the load bearing
structural shell of this chair can be given to a structural
engineer while the task of giving the chair a decorative exterior
appearance can be given to a designer. The separate labors of the
two men can be brought together into a single chair by utilizing
applicant's unique means for joining the trim shell to the
structural shell.
In accordance with this emphasis on design, other objects of the
invention include that of providing a recess in the seat covering
portion of the trim shell sufficiently large to accommodate and
hide from view that portion of a chair base which is to be secured
to the structural shell. The trim shell also hides from view the
edge of the upholstery used to cover the face of the structural
shell where the upholstery is wrapped around the peripheral edge of
the shell and secured to the rear side thereof. Unique arm
connections are provided which also can be hidden from view by
means of the decorative trim shell.
Finally, yet another aspect of this invention is directed towards
providing a unique cushion assembly whereby a plurality of cushions
are adhered in adjacent fashion to the face of the back portion of
the structural shell. The relative density of the different
cushions varies directly with the amount of weight which must be
supported by the portion of the shell back which is covered by that
cushion. This unique human engineering feature substantially
improves the comfort of applicant's chair.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects and advantages of this invention will be
seen by reference to the written specification and appended
drawings wherein:
FIG. 1 is an exploded view of the structural shell, trim shell and
chair base;
FIG. 2 is a perspective view of the rear side of the structural
shell;
FIG. 3 is a perspective view of the rear side or the exterior side
of the trim shell;
FIG. 4 is a perspective view of the fully assembled chair;
FIG. 5 is a perspective view of the structural shell and arm
assembly;
FIG. 6 is an exploded cross section taken along VI--VI of FIG.
4;
FIG. 7 is a perspective, cutaway view of the upper right-hand
portion of the trim shell;
FIG. 8 is a sectional view taken along VIII--VIII of FIG. 4;
and
FIG. 9 is a cross-sectional view of a portion of the chair showing
the connection of the base to the seat.
PREFERRED EMBODIMENT
In the preferred embodiment, the chair of this invention includes a
structural shell 10 which is to be seated within, and secured to a
trim shell 20 and mounted on a base 50 (FIG. 1). Shell 10 is
provided with a suitable covering 40 (FIG. 6) and may be provided
with arms 30 (FIG. 4). FIG. 4 shows a perspective view of the fully
assembled chair and it can be seen that when the chair is
assembled, structural shell 10 is completely hidden from view.
Structural shell 10 is formed by molding a high impact, expanded
polystyrene. It includes an integral seat and back and must be of
sufficient thickness that it will provide the structural support
for the chair without the aid of trim shell 20. It has been found
that a thickness of about three-eighths of an inch is suitable.
The bottom of shell 10 includes a rectangular rib 11 having T-nuts
12 located in the corners thereof to provide a means for mounting
chair base 50 (FIG. 2). Rib 11 is thicker than the rest of
structural shell 10 and accordingly provides additional rigidity
and support in this crucial area. Similar reinforcing support is
provided by ribs 13 which extend down the rear face of the shell
back and around to the shell bottom. As with rectangular rib 11,
these ribs 13 are thicker than structural shell 10 is generally and
thereby provide additional structural support. Finally, the
peripheral rim 10a of shell 10 is somewhat thicker than the rest of
shell 10 to minimize the possibility of cracking and splitting in
this region and to give shell 10 added rigidity.
Shell 10 includes a plurality of venting holes 14 in the seat
portion thereof (FIGS. 1 and 2) to allow the seat cushion 41 (FIG.
6) to vent. A plurality of tufting holes 15 are provided along the
junction between the seat and back portions of shell 10 to
facilitate tufting of the upholstery 45 as indicated at 46 in FIGS.
4 and 6.
To facilitate the mounting of arms 30, the peripheral portion of
shell 10 includes four recesses 16 (FIGS. 1 and 2), one being
located at each side of the seat portion of shell 10 and one being
located at each side of the back portion thereof. In order to
facilitate the securance of trim shell 20 to structural shell 10, a
pair of clips 17 are provided, each of which is bolted to the face
of shell 10 by bolts 18 (FIG. 8), and which extend rearwardly
through openings 19 in shell 10 and then extend vertically upwardly
on the rear side of shell 10 (FIGS. 1, 2 and 8). These upper
extremities are flanged, 17a in order to facilitate the easy
securance of trim shell 20.
Trim shell 20 is preferably injection molded of polypropylene. This
provides an impact resistant decorative shell at a reasonable cost.
It need only be sufficiently thick that it holds a desired design
configuration. It has been found that a thickness of about nine
sixty-fourths of an inch is acceptable.
Protruding from the inner face of shell 20 are a pair of clip wells
21 (FIGS. 1 and 7) which cooperate with clips 17 on shell 10 in
order to facilitate the joining of trim shell 20 to structural
shell 10. Each well 21 projects from the surface of trim shell 20
and has an open bottom as is indicated by the arrow in FIG. 7.
Trim shell 20 also includes a recessed portion 22 in the base or
seat covering portion thereof. This is sufficiently large to
accommodate the seat supporting pan 51 of chair base 50 when the
latter is secured to the assembled structural shell 10 and trim
shell 20. Holes 23 are provided at the four corners of recessed
portion 22 whereby nuts can pass through trim shell 20 into
structural shell 10.
Finally, a decorative bumper strip 24 is secured around the
peripheral edge of trim shell 20 (FIGS. 6 and 8). This strip is
preferably made of polyvinyl chloride and is channeled so as to
snap over the peripheral edge of trim shell 20. It serves as a
bumper and it also serves to fill any slight gaps between the edge
of trim shell 20 and structural shell 10.
If desired, arms 30 can be secured to structural shell 10 in the
manner indicated in FIG. 5. A curved steel rod 31 provides the
structural strength for arm 30. The ends of rod 31 wrap around the
peripheral edge of shell 10 to the rear of the seat portion at one
end and to the rear of the back portion at the other end. These end
portions of rod 31 reside in recessed channels 16 such that they do
not extend a substantial distance beyond the peripheral edge of
structural shell 10. They are then bolted to T-nuts embedded in
structural shell 10 by means of bolts 32 or the like.
A trim portion 33, preferably of compression molded matte finish
phenolic plastic, is secured over curved rod 31. It includes a
channel portion 34 which fits over and encompasses rod 31, and it
is bolted thereto by means of bolts 35 extending through rod 31 and
into well nuts embedded in trim 33.
The covering for structural shell 10 begins with a laminated seat
cushion 41 which is adhered by adhesive to the seat portion of
structural shell 10. The first layer of laminate is a very firm
density polyurethane material while the second layer is a softer
density polyurethane material. A medium density cushion 42 is
adhered by means of adhesives to the face of the back portion of
structural shell 10 in the area which will have to support the
lumbar region of a person seated on the chair. A softer urethane
cushion 43 is adhered to the face of structural shell 10 in the
shoulder supporting regions thereof (FIG. 6). In this manner, the
lumbar region of a person's back is supported by a heavier density
cushion 42 while the shoulder regions, which require less support,
are supported by a softer foam cushion 43.
The cushions 41, 42 and 43 are covered with a continuous layer of
padding material 44 which in turn is covered with upholstery 45.
Both the continuous layer of padding 44 and the upholstery 45 are
wrapped around the peripheral edge of structural shell 10 and are
secured to the rear side thereof by means of staples 49 or the like
(FIG. 8). Staples 49 are preferable since it is easier to staple
than to glue. Thus, it is significant that structural shell 10 is
rigid and dense such that it will hold staples 49 properly.
Upholstery 45 can be tufted as at 46 (FIGS. 4 and 6) by sewing
threads 47 through upholstery 45 at selected points, pulling both
ends of each thread 47 through a hole 15, and stapling the ends of
the thread to the rear face of structural shell 10 by means of
staples 48.
Once the covering material 40 and the arms 30 are in place on shell
10, trim shell 20 can be secured to shell 10. The flanged ends 17a
of clips 17 are slipped into the openings in the clip wells 21 on
trim shell 20. Because the clips are flanged at their end portion
17a, they can be more easily located with respect to clip wells 21
and can be more easily slid into position. The rods 31 of arms 30
are recessed in channels 16, extending no farther beyond the
peripheral edge 10a than the thickness of upholstery 45 and padding
44. Thus, the perimeter of trim shell 20 fits snugly against
structural shell 10.
With structural shell 10 and trim shell 20 so joined, base 50 can
be secured to structural shell 10. Base 50 is aligned such that its
seat supporting pan 51 is positioned within recess 22 in trim shell
20 (FIG. 7). Bolts 52 are passed through holes in the four corners
of seat supporting pan 51, through the holes 23 in recessed portion
22 of trim shell 20 and into the T-nuts 12 which are embedded at
the corners of rectangular rib 11 of structural shell 10. By
passing through trim shell 20, bolts 52 serve not only to secure
structural shell 10 to base 50, but also to provide additional
securance of trim shell 20 to structural shell 10.
Because of the unique construction outlined above, the edge of
upholstery 45 and the means securing it to the rear of structural
shell 10 are completely hidden from view by trim shell 20.
Similarly, the ends of arms 30 which are joined to the rear of
structural shell 10 are hidden. Because of the recessed channels
16, the passage of the arm supporting rods 31 around to the rear of
structural shell 10 does not in any way interfere with the close
fit which is achieved between the peripheral edge of trim shell 20
and structural shell 10. The unique arrangement of different
density cushions on different portions of the back of structural
shell 10 insures maximum comfort from the chair of this invention.
Because all of the cushions 41, 42 and 43 are held by adhesive to
the face of structural shell 10, they cannot bunch and shift
around. This is also true of padding 44 since it comprises a
continuous layer which is stapled to the rear of structural shell
10 at its peripheral edge.
It is also significant that the structural shell 10 and the trim
shell 20 when joined together render structural shell 10 more rigid
than it is when standing alone. Thus, this lamination which is
achieved by tightly securing the two shells together makes it
possible to use less costly construction in manufacturing
structural shell 10.
Most importantly, maximum compatibility is achieved between the
design objectives of providing structural strength and attractive
appearance. Even though the material of which structural shell 10
is constructed does not have a suitable surface appearance for many
purposes, it can be used in the construction of this chair for any
purpose since the structural shell 10 is completely hidden from
view when the chair is assembled. Applicant has created a unique
marriage of heretofore divergent design objectives and accordingly,
has made a significant contribution to the chair design art.
It will be understood that the above is merely a preferred
embodiment of this invention and that many alterations and changes
can be made without departing from the spirit and broader aspects
of the invention.
* * * * *