U.S. patent application number 10/369444 was filed with the patent office on 2004-08-19 for chair seat with firm but resilient front edge.
This patent application is currently assigned to Homecrest Industries, Inc.. Invention is credited to Bottemiller, Donald L..
Application Number | 20040160109 10/369444 |
Document ID | / |
Family ID | 32850338 |
Filed Date | 2004-08-19 |
United States Patent
Application |
20040160109 |
Kind Code |
A1 |
Bottemiller, Donald L. |
August 19, 2004 |
Chair seat with firm but resilient front edge
Abstract
A chair having a seat formed from two spaced-apart rails
extending along opposing sides and unsupported along a forward
portion of the seat. A flexible and elastic fabric extends between
and is held in tension by the two spaced-apart rails. A flexible
and relatively inelastic elastic border extends along a peripheral
edge of the along a forward edge of the fabric. The border extends
between and is held in tension by the two spaced-apart rails to
restrict the stretch of the fabric to support a seated user's
legs.
Inventors: |
Bottemiller, Donald L.;
(Wadena, MN) |
Correspondence
Address: |
WESTMAN CHAMPLIN & KELLY, P.A.
SUITE 1600 - INTERNATIONAL CENTRE
900 SECOND AVENUE SOUTH
MINNEAPOLIS
MN
55402-3319
US
|
Assignee: |
Homecrest Industries, Inc.
Wadena
MN
|
Family ID: |
32850338 |
Appl. No.: |
10/369444 |
Filed: |
February 19, 2003 |
Current U.S.
Class: |
297/440.11 |
Current CPC
Class: |
A47C 7/282 20130101;
A47C 7/40 20130101; A47C 31/02 20130101; A47C 5/06 20130101 |
Class at
Publication: |
297/440.11 |
International
Class: |
A47C 007/00; A47C
007/02 |
Claims
1. A chair having a seat comprising: two spaced-apart rails
extending along opposing sides and unsupported along a forward
portion of the seat between the two spaced-apart rails; a flexible
fabric extending between and held in tension by the two
spaced-apart rails, the flexible fabric capable of stretching in at
least one direction; and a border along a forward edge of the
flexible fabric, the border extending between and held in tension
by the two spaced-apart rails, the border having sufficient
strength to support a seated user's legs.
2. The chair of claim 1, wherein the flexible fabric is an envelope
comprising: two sheets of the flexible fabric attached along the
peripheral edges with the border; and an opening in one of the two
sheets.
3. The chair of claim 1, further comprising: cross-braces disposed
along the two spaced apart rails at a spacing intervals for
connecting the two spaced-apart rails and for maintaining
separation between the two spaced-apart rails.
4. The chair of claim 1, wherein the border is less elastic than
the flexible fabric.
5. The chair of claim 1, wherein the flexible fabric and the border
each have a characteristic elasticity.
6. The chair of claim 5, wherein the flexible fabric and the border
define defining an elasticity ratio of approximately 6 to 1.
7. The chair of claim 1, further comprising: one or more ground
engaging mechanisms attached to the two spaced apart rails.
8. The chair of claim 1, further comprising: a resilient wire
connecting the two spaced rails at one end to form a head rest
area.
9. The chair of claim 1, wherein the rails are formed from a
unitary piece of material, and are shaped in substantially an
L-shape.
10. A method of assembling a chair comprising: assembling at least
one end of a chair frame having two spaced apart-rails that form a
seat portion having an unsupported forward edge; tensioning a
flexible fabric having a border over the chair flame such that the
border extends between the two spaced apart rails along the
unsupported forward edge; wherein the border is less elastic than
the flexible fabric.
11. The method of claim 10, wherein the border is flexible.
12. The method of claim 10, wherein the step of tensioning
comprises: inserting the at least one assembled end of the chair
frame into a fabric envelope having an opening; advancing the chair
frame through the opening until the at least one assembled end of
the chair frame can advance no further inside the envelope; and
attaching cross-braces at predetermined locations along the
spaced-apart rails in order to fixedly position the spaced-apart
rails at a distance from one another.
13. A contoured chair having a seat comprising: two rails spaced
apart by cross-braces in a substantially parallel position to one
another; an elastic material extending between the two rails to
form a seat portion that is unsupported structurally at a forward
edge; and a border material extending between the two rails at the
forward edge, the border material being less elastic than the
elastic material, the border material providing support for a
user's legs.
14. The chair of claim 13, further comprising: legs attached to the
two rails.
15. The chair of claim 13, wherein the elastic material has a
different modulus of elasticity in a weft direction than in a warp
direction.
16. The chair of claim 13, wherein the elastic material is a woven
from all-weather, vinyl-coated, flexible and elastic polyester
yarn.
17. The chair of claim 13, wherein the border material restricts a
stretch of the elastic material when weight is placed on the seat
portion of the chair.
18. The chair according to claim 13, wherein the border material
and the elastic material have a ratio of elasticity of
approximately one-sixth.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] None.
FIELD OF THE INVENTION
[0002] The present invention relates to a chair construction, and
more specifically, the present invention relates to a chair
construction employing two fabrics of substantially different
elasticity to form a fabric envelope for stretching over a metal
framework.
BACKGROUND OF THE INVENTION
[0003] Outdoor furniture having an envelope of flexible material
stretched over metal framework is well known. One example of such
furniture is described in U.S. Pat. No. 4,592,126 issued to
Bottemiller on Jun. 3, 1986, which is entitled "Method for
Constructing Furniture Having a Flexible Sheet Portion" and which
is incorporated herein by reference.
[0004] Typically, this type of furniture consists of a fabric
envelope held in tension between first and second spaced-apart
parallel rails, which are held apart by a number of cross-members
or braces. The flexible fabric envelope is generally constructed of
two sheets of fabric sown together along the entire perimeter with
an opening on the back side of one of the sheets. The opening is
typically located on the back side and near the bottom so as to
hide or mask the opening and to allow for ease of assembly.
[0005] Generally, the furniture is assembled by attaching a wire
member to the top of each rail. The bottom ends of the rails are
then pushed toward one another. The opening in the fabric envelope
is slid over the top end, and the top of the flexible fabric
envelope is pulled over the wire member and the top of the rails,
and the bottom of the flexible fabric envelope is pulled over the
bottom of the rails. The bottom end of the rails are then pulled
apart and spaced from one another by cross-members, which put the
fabric envelope in tension and which support the rails. A method of
constructing the fabric furniture consistent with the present
invention is detailed in U.S. Pat. No. 6,345,446, which is
incorporated herein by reference.
[0006] Traditionally, such flexible fabrics have included canvas,
vinyl-coated polyester fabric, and other similar fabrics. However,
over time, the traditional fabrics used for such chairs tend to
deteriorate from usage. After many uses, the fabric can no longer
maintain its original appearance, and no longer returns to its
original form after use. There is a need within the industry for a
comfortable, supportive, fabric chair that is easy to manufacture
and that maintains its appearance over time.
BRIEF SUMMARY OF THE INVENTION
[0007] A chair has a seat formed by two spaced-apart rails
extending along opposing sides of the seat portion and a flexible
and elastic fabric extending between the two rails. The seat
portion is unsupported along a forward portion of the seat between
the two rails. A flexible and less-elastic border extends along a
forward edge of the fabric, extending between the two rails. When a
user sits on the seat portion, the elastic fabric stretches and
flexes to cushion and support the user. At the same time, the
border flexes to provide a comfortable forwward portion of the
seat, and yet the border has sufficient strength to restrict the
elasticity of the flexible and elastic fabric along the forward
edge of the seat portion to provide firm and comfortable support
for a user's legs.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a perspective view of the front of a chair
constructed by the method of the present invention.
[0009] FIG. 2 is a perspective view of the bottom of a chair
constructed by the method of the present invention.
[0010] FIG. 3 is a perspective view of the rear of a chair
constructed by the method of the present invention.
[0011] FIG. 4 is a perspective view of the wire member being
inserted into the top ends of the rails.
[0012] FIG. 5 is a perspective view of the spaced apart rails and
the wire member being inserted within the flexible envelope.
[0013] FIG. 6 is a cross-sectional view of the wire member and a
rail enclosed within the fabric envelope.
[0014] FIG. 7 is a graph illustrating the relative elasticity of
the sheet material and the border material.
DETAILED DESCRIPTION
[0015] Conceptually, the furniture construction of the present
invention involves two materials having different elastic
properties: a flexible and elastic fabric and a flexible and
relatively inelastic border. To form the furniture, the flexible
and elastic fabric is stretched over two spaced-apart rails and is
held in tension by the two rails. The two spaced-apart rails hold
the fabric in tension to form a seat. The forward portion of the
seat (the area behind a user's knees when seated) is unsupported by
the rail or by any frame element along a forward edge. Instead, the
elastic fabric is bordered by the relatively inelastic border along
its forward edge. The border fabric extends between the two spaced
apart rails at the forward edge of the fabric. The border fabric
restricts the elasticity of the flexible and elastic fabric along
the forward edge of the seat portion, such that the forward edge of
the seat portion provides a firm and comfortable support for the
back of a user's legs when seated on the furniture.
[0016] The furniture construction of the present invention is
illustrated by chair 10 in FIGS. 1, 2 and 3. The chair 10 includes
ground engaging supports 12,14, a flexible and elastic fabric
envelope 16, and a support structure 18 for supporting and holding
the envelope 16 in tension, defining a seat portion 20, a back
portion 22, and a head rest portion 24. The support structure 18 is
connected to the ground engaging supports 12,14. As used with this
application, the term "construction" refers to both original
construction of furniture and reconstruction of furniture to
replace the envelope 16.
[0017] In the embodiment shown, each ground engaging support 12,14
is shown as a generally arcuate shape, wherein the open ends touch
the ground. Each ground engaging Support 12, 14 is formed from a
unitary piece of material, which serves as a front leg 26, a rear
leg 28 and an arm rest 30. Other ground engaging support
structures, such as those shown in U.S. Pat. Nos. 4,529,126 and
6,345,446 (both incorporated herein by reference), could also be
employed with the construction of the present invention.
[0018] The envelope 16 is formed from two sheets of flexible,
elastic material, an upper sheet 32 and a lower sheet 34, attached
along their respective outside perimeters by a relatively inelastic
border material 36. The lower sheet 34 also contains an opening 38
located near one end of the envelope 16, preferably near the seat
portion 20. To construct the chair 10, the support structure 18 is
inserted through the opening 38, as illustrated in FIG. 4.
Generally, the support structure 18 is inserted through the opening
38 facing such that ultimately the opening 38 is positioned under
the seat portion 20 and is substantially out of sight.
[0019] The support structure 18 includes first and second spaced
apart rails 42,44, respectively. The rails 42,44 are substantially
"L"-shaped, and preferably have a contour that defines the shape of
the chair 10 as illustrated in FIG. 5. When inserted within the
envelope 16 and spaced apart, the rails 42 and 44 simultaneously
provide the structure and contour for the seat and back portions,
20 and 22, of the chair construction. Thus, the back portion 20 and
seat portion 22 are visually continuous with no defining line
distinguishing the two.
[0020] The rails 42 and 44 are initially held apart at the top of
the back portion 22 by a resilient wire member 46, which forms a
head rest portion 24 with the envelope 16. Finally, the rails 42
and 44 are held apart by a plurality of cross-braces 50 located on
the seat and back portions 20 and 22. The spaced apart rails 42,44
also include a plurality of openings 52 for engagement with the
cross-braces 50 as is well known in the art. Generally, each
cross-brace 50 is fastened at each end to the rails 42,44 by
positioning a fastener 54 (such as a bolt and nut) through
corresponding openings 52 on rails 42,44 and through an opening
(not shown) on the end of the cross-brace 50. It should be
understood that the number of cross braces may vary depending on
the type of chair, lounge, swing chair, or other similar furniture
construction that utilizes the elastic and flexible envelope with a
similar support structure.
[0021] While the number of cross braces may vary, the cross braces
50 serve only to maintain the separation between the rails 42,44.
The cross braces provide no direct support for a seated user.
Instead, the flexible and elastic fabric envelope 16, which is held
in tension by the rails 42,44, provides support for the seated
user. Additionally, the border 36 restrains the elasticity along
the forward edge of the seat portion 20 to provide a comfortable
and firm support at the forward edge of the seat portion 20, such
as behind the seated user's knees. In general, the envelope 16
stretches to conform to the user's body. The border 36 stretches
less than the rest of the envelope 16, such that the seat portion
20 deforms to a mildly bowl-like shape when supporting a seated
user.
[0022] In one embodiment shown, the support structure 18 is
attached to the ground engaging supports 12,14 at two attachment
locations corresponding to the locations of two cross-braces 50.
Specifically, supports 12,14 are provided with flanges 40, which
interface with openings 52 on the rails 42,44. The flanges 40 are
then attached to the rails 42,44 with the cross-brace 50 with the
same fastener 54.
[0023] As shown in FIG. 4, the rails 42,44 are provided with wire
openings or slots 56 on top ends 58,60 to receive the bent ends
64,66 of the resilient member 46. Additionally, the rails 42,44 are
provided with cross-brace openings 52 for receiving a fastener 54
to connect cross-braces 50 to the support structure 18. Generally,
each of the ends 64,66 of the resilient wire member 46 is inserted
into a wire opening 56 on each of the top ends 58,60 of the rails
42,44. In the preferred method, the resilient wire member 46 is
assembled to the rails 42,44 before inserting the rails 42,44 into
the envelope 16.
[0024] The resilient wire member 46 is preferably made of metal and
has a generally central arcuate shape extending in a generally
upward direction, with each end 64 and 66 bent approximately
perpendicularly downward. The wire member 46 provides flexible,
spring-like action which improves head support and the overall
comfort of the chair by accommodating tensions applied on the
flexible envelope 16 from the movement of a sitting occupant. The
arcuate shape provides an aesthetically pleasing contoured curve to
the head rest portion 24 of the chair 10. While the preferred
embodiment of the present invention describes the resilient wire
member 46 as having an arcuate shape, it should be understood that
alternative embodiments are well within the scope of the present
invention. Such alternative embodiments include, but are not
limited to, contours with a single or a plurality of raised or
lowered portions, straight members, and ornamentally designed
members.
[0025] As shown in FIG. 5, once the resilient member 46 has been
inserted into the slots 56 on each rail 42,44, the rails 42,44 are
held apart at a fixed distance at the top ends 58,60 of the rails
42,44. Then, the bottom ends 68 and 70 of the rails 42,44 are
brought closer to one another while the top ends 50 and 52 remain a
fixed distance apart from one another. The top ends 58,60 of the
rails 42,44 are then inserted into the flexible envelope 16 through
the opening 38 located on the lower layer 22. It should be
appreciated that since the bottom ends of the rails 68 and 70 are
closer to one another than the top ends 58,60 of the rails 42,44,
the envelope 16 is slack and not in tension when the rails 42,44
are being inserted. By inserting the rails 42,44 into a slack
flexible envelope 16, the assembly is much easier than if the rails
42,44 were held apart and the envelope 16 was placed into
tension.
[0026] The spaced apart rails 42,44 and flexible wire member 46 are
inserted within the envelope 16 until the flexible wire member 46
and top ends 58,60 of the rails 42,44 reach the top of the envelope
16. The top of the envelope 16 is formed in a shape corresponding
to the contour of the wire member 46, so that the wire member 46
cooperates with the top of the envelope 16. While the bottom ends
68,70 of the rails 42,44 are still close to one another, the lower
layer 34 of the envelope 16 is placed over the bottom ends 68,70 of
the rails 42,44. The position of the opening 24 in the lower layer
34 of the envelope 16 after assembly is illustrated in FIG. 2.
[0027] With the spaced apart rails 42,44 fully inserted within the
envelope 16, the rails 42,44 are positioned so that the envelope 16
is brought into a state of tension. It should be appreciated that
the use of a special tool to place the envelope 16 in tension is
not needed due to the addition of the resilient wire member 46
located at the top 58,60 of the spaced apart rails 42,44. The
resilient wire member 46 acts as a fulcrum between the two spaced
apart rails 42,44, which aides in the assembly of the chair 10. An
assembler spaces the bottom ends 68,70 of the rails 42,44 apart to
place the envelope 16 in tension. The assembler then needs only to
attach the cross-braces 50 to the support structure 18, and attach
the support structure 18 to the ground engaging supports 12,14 in
order to complete the chair construction 10.
[0028] As shown in FIG. 6, the chair 10 is shown in cross-section
taken through rail 42. The envelope 16 is in tension over the rail
42. As shown, fasteners 54 are shown inserted through rail 42, and
through cross-braces 50 (and through flanges 40 where the ground
engaging support 12 attaches to the rail 42, according to the
embodiment shown in FIGS. 1-3). As previously mentioned, the
cross-braces 50 serve only to separate the rails 42,44, and do not
provide actual support to a seated user. Additionally, the rails
42,44 are hollow, which contributes to the light weight of the
overall chair construction 10.
[0029] Generally, the envelope 16 has a border 36 that extends
along its peripheral edges. In cross-section, in FIG. 6, the
relatively inelastic border 36 is shown on either end of the rail
42. As previously discussed, the border 36 along the forward edge
of the seat portion 20 of the chair 10 extends between the rails
across the entire forward edge of the seat portion 20.
Specifically, the border 36 along the forward edge of the seat
portion 20 is held in tension by the rails 42,44 and serves to
restrict the elasticity of the envelope 16 along the forward edge
of the seat portion 20. Since the border 36 is less elastic than
the material of the envelope 16, the border 36 limits the
elasticity of the envelope 16 along its entire periphery. At the
forward edge of the seat portion 20, by limiting the elasticity of
the envelope 16, the border 36 provides leg support for a seated
user by not permitting the fabric envelope 16 to stretch as much as
it does in other areas of the seat portion 20 (such as at the
center of the seat portion).
[0030] As previously mentioned, the envelope 16 is constructed of
two sheets of flexible, elastic fabric, an upper sheet 32 and a
lower sheet 34, bound together at their respective peripheral edges
with a flexible and relatively inelastic border 36. The elastic
fabric material is generally elastic in the weft direction, but may
have a different elasticity in the warp direction. In one
embodiment, the fabric material is formed into the envelope 16 such
that the weft direction of the fabric material extends laterally
between the rails 42,44 when stretched, and the warp direction
corresponds with the longitudinal direction from the resilient wire
member 46 to the front of the seat portion 20 of the chair 10.
Thus, in one embodiment, the sheet material stretches substantially
more between the rails 42,44 than longitudinally along the length
of the chair 10. Generally, the elastic material can be selected
according to the elastic characteristics in weft and warp
directions in order to maximize the comfort of the seated user.
[0031] When stretched over the support structure 18, the upper and
lower sheets 32,34 and the border 36 are in tension. As weight is
applied to the seat portion 20, the back portion 22, and the head
rest portion 24, the flexible fabric sheets 32,34 and the border 36
stretch. However, the flexible fabric sheets 32,34 are more elastic
than the border 36. The border 36 thus restricts the stretch of the
more flexible fabric sheets 32,34.
[0032] In the present invention, the flexible and elastic fabric
sheets 32,34 stretch to Cushion and to provide support for a
sitting person, and the relatively inelastic border 36 restricts
the stretch of the sheets 32,34 such that the border 36 assists the
fabric sheets 32,34 in providing greater support behind the sitting
person's knees. More specifically, the fabric in the seat portion
20 stretches while the border 36 positioned at the end of the seat
portion 20 (i.e. behind the knees) stretches less, thereby creating
a cupped (or bowl-shaped) seat area having greater comfort and
stability than a fabric chair having only one type of fabric. The
combination of an elastic fabric sheet 32,34 and a relatively
inelastic fabric border 36 in the present invention allows for a
chair construction 10 having no structural element across the front
of the seat portion 20, while still providing support for the back
of the legs.
[0033] FIG. 7 illustrates the elasticity of the sheet fabric 32,34
as compared with the elasticity of the relatively inelastic border
36. As shown, the elasticity of both fabrics was tested using
samples that were 4 inches wide and 24 inches long. The fabric was
tested in both the warp and weft directions (as the fabric is
applied to the chair structure), and the stretch aspect of the
fabric is shown in the weft direction (e.g. in the direction
transverse to the parallel rails 42,44 in the plane of the
seat).
[0034] In one embodiment, the stretch fabric is woven from
all-weather, vinyl-coated, flexible and elastic polyester yarn,
such as Phifertex.RTM. fabric made by Phifer Wire Products, Inc. of
Tuscaloosa, Ala. By contrast, border fabrics can be formed from any
all-weather material having a much lower elasticity than the
stretch fabric. In one embodiment, the border fabric is cashmere.
Other border fabrics include Holly, Sable, and other similar,
relatively inelastic fabric materials.
[0035] As shown, two inches of fabric at each end of the sample was
clamped and the fabric was stretched to determine the number of
pounds required to stretch the fabric to a particular measurement.
For test purposes, no fabric was stretched beyond four inches. All
samples of the stretch fabric and the border fabric, when tested in
the longitudinal direction (e.g. in the direction from the head
rest to the seat), failed at a stretch of between 2 and 3 inches
(e.g. between 22 and 23 inches, beginning with a 20 inch
sample).
[0036] The border samples in the lateral direction were consistent
with each other, (the chart below shows the average a Cashmere, a
Holly and a Sable sample). All of these border samples failed
between 22 and 22.5 inches.
[0037] In the lateral direction, the elastic fabric sheets 32,34
exhibited elastic qualities beyond four inches (e.g. beyond 24
inches, beginning with a 20 inch sample). As shown in the graph,
both the elastic fabric 32,34 and the relatively inelastic border
36 exhibit elastic characteristics as a linear relationship between
stretch in inches as a function of the weight in pounds. As shown,
the slope of the graph of the elastic fabric is approximately 0.05,
while the slope of the graph of the inelastic fabric is
approximately 0.0075. Thus, in one embodiment the ratio of
elasticity between the elastic and the relatively inelastic fabrics
is 1 to 0.15, or approximately 6.67 inches of stretch to every 1
inch of stretch for the relatively inelastic fabric.
[0038] Using this or a similar ratio of about 6 to 1, various
combinations of elastic and relatively inelastic fabrics could be
combined to perform the present invention. Moreover, to adjust the
comfort of the chair, the fabric may be selected to have a
different elasticity in the warp and weft directions. Moreover, the
ratio of the elastic to inelastic fabrics may be adjusted such that
the ratio is larger or smaller, depending on whether more or less
support behind the legs is desirable.
[0039] In the embodiment shown, using the Phifertex.RTM. fabric
described above, the sheet material 32,34 was stretched
approximately 6% as the rails 42,44 are spaced apart. The less
elastic border 36, which is sown around the entire periphery of the
elastic sheet material 32,34, including across the front of the
seat portion 20. When the border 36 is stretched along with the
sheet material 32,34 of the seat portion 20, the border creates an
edge that provides a resilient and flexible, but firm, front to the
chair 10. Thus, the chair 10 looks like other known chairs, but
performs much differently in that the material conforms to the
individual body shape for enhanced comfort, and recovers to a taut
surface as soon as the individual stands up from the chair 10.
[0040] With the present invention, the chair 10 has no structural
support along a forward edge of the seat portion 20, and yet
forward edge support is provided for a seated user by a border 36
that is less elastic than the envelope 16, which provides the
support for the seat, back and head of the seated user. While the
chair 10 shown in the figures illustrates a contoured design that
provides some leg support due to the contour of the forward edge of
the seat portion 20, the border material 36 provides firmer
support, without the assembly time, additional costs, and weight
associated with a structural support. Thus, the border 36 provides
the necessary support for a comfortable and firm seat area with
less material cost, less assembly time, and less overall
weight.
[0041] Although the present invention has been described with
reference to preferred embodiments, workers skilled in the art will
recognize that changes may be made in form and detail without
departing from the spirit and scope of the invention.
* * * * *