U.S. patent application number 11/078135 was filed with the patent office on 2005-09-22 for folding chair with armests.
Invention is credited to Haney, Thayne B., Smith, Brandon, Winter, David C..
Application Number | 20050206202 11/078135 |
Document ID | / |
Family ID | 35062955 |
Filed Date | 2005-09-22 |
United States Patent
Application |
20050206202 |
Kind Code |
A1 |
Winter, David C. ; et
al. |
September 22, 2005 |
Folding chair with armests
Abstract
A lightweight folding chair may include one or more armrest. The
armrests are preferably pivotally attached to the chair so that the
armrests can be moved between a storage position and a use
position. The armrests are also preferably pivotally connected to
the front legs of the chair, but the armrests can be connected to
any suitable portions of the chair. The chair may also include a
seat with an interference fit support bracket. The seat may have a
lightweight seat member constructed of a lightweight material, such
as a blow-molded plastic, that is generally supported by two such
support brackets. The support brackets may be affixed to the
lightweight seat member by sliding the lightweight seat member into
interference engagement with the support brackets.
Inventors: |
Winter, David C.; (Layton,
UT) ; Haney, Thayne B.; (Syracuse, UT) ;
Smith, Brandon; (Ogden, UT) |
Correspondence
Address: |
WORKMAN NYDEGGER
(F/K/A WORKMAN NYDEGGER & SEELEY)
60 EAST SOUTH TEMPLE
1000 EAGLE GATE TOWER
SALT LAKE CITY
UT
84111
US
|
Family ID: |
35062955 |
Appl. No.: |
11/078135 |
Filed: |
March 10, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11078135 |
Mar 10, 2005 |
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11030427 |
Jan 6, 2005 |
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11030427 |
Jan 6, 2005 |
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10390312 |
Mar 17, 2003 |
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6871906 |
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10390312 |
Mar 17, 2003 |
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09774405 |
Jan 31, 2001 |
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6543842 |
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60180417 |
Feb 3, 2000 |
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60555747 |
Mar 22, 2004 |
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Current U.S.
Class: |
297/23 ; 297/55;
297/58 |
Current CPC
Class: |
A47C 7/541 20180801;
A47C 3/045 20130101; A47C 4/04 20130101; A47C 1/03 20130101 |
Class at
Publication: |
297/023 ;
297/055; 297/058 |
International
Class: |
A47C 004/00; A47C
004/04 |
Claims
What is claimed is:
1. A folding chair that is capable of being moved between a first
position for supporting a person and a second position for storage,
the folding chair comprising: a first leg assembly; a second leg
assembly; a chair seat constructed from blow-molded plastic and
including an upper surface, a lower surface generally spaced apart
from the upper surface, and a generally hollow interior; a first
metal support bracket connected to the first leg assembly, the
first support bracket including a first attachment portion with an
inwardly extending lip and a second attachment portion with an
inwardly extending lip, at least a portion of the first attachment
portion being sized and configured to abut a first portion of the
chair seat and the inwardly extending lip being sized and
configured to be inserted into a groove in the first portion of the
chair seat, at least a portion of the second attachment portion
being sized and configured to abut a second portion of the chair
seat and the inwardly extending lip being sized and configured to
be inserted into a groove in the second portion of the chair seat;
and a second metal support bracket connected to the second leg
assembly, the second support bracket including a first attachment
portion with an inwardly extending lip and a second attachment
portion with an inwardly extending lip, at least a portion of the
first attachment portion being sized and configured to abut a third
portion of the chair seat and the inwardly extending lip being
sized and configured to be inserted into a groove in the third
portion of the chair seat, at least a portion of the second
attachment portion being sized and configured to abut a fourth
portion of the chair seat and the inwardly extending lip being
sized and configured to be inserted into a groove in the fourth
portion of the chair seat.
2. The folding chair as in claim 1, further comprising: a first
armrest pivotally connected to the first leg assembly and movable
between a use and a storage position; and a second armrest
pivotally connected to the second leg assembly and movable between
a use and a storage position.
3. The folding chair as in claim 2, further comprising: a first
plurality of stops sized and configured to limit the movement of
the first armrest to a particular range of motion; and a second
plurality of stops sized and configured to limit the movement of
the second armrest to a particular range of motion.
4. The folding chair as in claim 3, further comprising: a first
bracket connected to the first leg assembly and including the first
plurality of stops; and a second bracket connected to the first leg
assembly and including the second plurality of stops.
5. The folding chair as in claim 2, further comprising: a first
stop sized and configured to maintain the first armrest in the
storage position; a second stop sized and configured to maintain
the first armrest in the use position; a third stop sized and
configured to maintain the second armrest in the storage position;
and a fourth stop sized and configured to maintain the second
armrest in the use position.
6. The folding chair as in claim 2, further comprising: at least
one stop sized and configured to limit the movement of the first
armrest; and at least one stop sized and configured to limit the
movement of the second armrest.
7. The folding chair as in claim 2, wherein the first leg assembly
includes a first leg connected to the first armrest and the second
leg assembly includes a second leg connected to the second armrest
and wherein the first leg and the first armrest are generally
aligned when the first armrest is in the storage position, and the
second leg and the second armrest are generally aligned when the
second armrest is in the storage position.
8. A folding chair that is capable of being moved between a use
position and a storage position, the folding chair comprising: a
first leg assembly; a first link connected to the first leg
assembly; a first support bracket connected to the first leg
assembly and including a first attachment portion that is disposed
at an angle relative to a second attachment portion; a second leg
assembly; a second link connected to the second leg assembly; a
second support bracket connected to the second leg assembly and
including a first attachment portion that is disposed at an angle
relative to a second attachment portion; a chair seat constructed
from blow-molded plastic connected to the first support bracket and
the second support bracket, the blow-molded plastic chair seat
including an upper surface, a lower surface generally spaced apart
from the upper surface, a first attachment portion that is attached
to the first attachment portion of the first support bracket, a
second attachment portion that is attached to the first attachment
portion of the second support bracket, a third attachment portion
that is attached to the second attachment portion of the first
support bracket, and a fourth attachment portion that is attached
to the second attachment portion of the second support bracket; a
first armrest connected to the first leg assembly and movable
between a use and a storage position; and a second armrest
connected to the second leg assembly and movable between a use and
a storage position.
9. The folding chair as in claim 8, further comprising: a first
plurality of stops sized and configured to limit the movement of
the first armrest to a particular range of motion; and a second
plurality of stops sized and configured to limit the movement of
the second armrest to a particular range of motion.
10. The folding chair as in claim 9, further comprising: a first
bracket connected to the first leg assembly and including the first
plurality of stops; and a second bracket connected to the first leg
assembly and including the second plurality of stops.
11. The folding chair as in claim 8, further comprising: a first
stop sized and configured to maintain the first armrest in the
storage position; a second stop sized and configured to maintain
the first armrest in the use position; a third stop sized and
configured to maintain the second armrest in the storage position;
and a fourth stop sized and configured to maintain the second
armrest in the use position.
12. The folding chair as in claim 8, further comprising: at least
one stop sized and configured to limit the movement of the first
armrest; and at least one stop sized and configured to limit the
movement of the second armrest.
13. The folding chair as in claim 8, wherein the first leg assembly
includes a first leg connected to the first armrest and the second
leg assembly includes a second leg connected to the second armrest
and wherein the first leg and the first armrest are generally
aligned when the first armrest is in the storage position, and the
second leg and the second armrest are generally aligned when the
second armrest is in the storage position.
14. A folding chair that is capable of being moved between a first
position for supporting a person and a second position for storage,
the chair comprising: a first front leg; a first rear leg; a first
armrest constructed from metal, connected to first front leg and
movable between a use and a storage position; and a first link
connected to the first front leg and the first rear leg; a second
front leg; a second rear leg; a second armrest constructed from
metal, connected to the second front leg and movable between a use
and a storage position; a second link connected to the second front
leg and the second rear leg; a chair seat including an upper
surface and a lower surface, the chair seat constructed from
blow-molded plastic as a unitary, one-piece structure, the chair
seat including a generally hollow interior portion; a first groove
formed in the chair seat as part of the unitary, one-piece
structure; a second groove formed in the chair seat as part of the
unitary, one-piece structure; a third groove formed in the chair
seat as part of the unitary, one-piece structure; a fourth groove
formed in the chair seat as part of the unitary, one-piece
structure; a first bracket including a first lip that is at least
partially inserted into the first groove in the chair seat and a
second lip that is at least partially inserted into the second
groove in the chair seat, the first bracket being connected to the
first front leg and the first rear leg; and a second bracket
including a first lip that is at least partially inserted into the
third groove in the chair seat and a second lip that is at least
partially inserted into the fourth lip in the chair seat, the
second bracket being connected to the second front leg and the
second rear leg.
15. The folding chair as in claim 14, further comprising: a first
plurality of stops sized and configured to limit the movement of
the first armrest to a particular range of motion; and a second
plurality of stops sized and configured to limit the movement of
the second armrest to a particular range of motion.
16. The folding chair as in claim 15, further comprising: a first
bracket connected to the first leg assembly and including the first
plurality of stops; and a second bracket connected to the first leg
assembly and including the second plurality of stops.
17. The folding chair as in claim 14, further comprising: a first
stop sized and configured to maintain the first armrest in the
storage position; a second stop sized and configured to maintain
the first armrest in the use position; a third stop sized and
configured to maintain the second armrest in the storage position;
and a fourth stop sized and configured to maintain the second
armrest in the use position.
18. The folding chair as in claim 14, further comprising: at least
one stop sized and configured to limit the movement of the first
armrest; and at least one stop sized and configured to limit the
movement of the second armrest.
19. The folding chair as in claim 14, wherein the first front leg
and the first armrest are generally aligned when the first armrest
is in the storage position, and the second front leg and the second
armrest are generally aligned when the second armrest is in the
storage position.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to and the benefit of U.S.
Provisional Patent Application Ser. No. 60/555,747, entitled
FOLDING CHAIR WITH ARMRESTS, which was filed on Mar. 22, 2004,
which is incorporated by reference. This application is a
continuation-in-part of U.S. patent application Ser. No.
11/030,427, entitled PORTABLE FOLDING CHAIR, filed on Jan. 6, 2005,
which is a continuation of U.S. patent application Ser. No.
10/390,312, entitled PORTABLE FOLDING CHAIR, filed on Mar. 17,
2003, which is a continuation of U.S. patent application Ser. No.
09/774,405, entitled INTERFERENCE FIT SUPPORT BRACKET FOR A
PORTABLE FOLDING CHAIR, filed on Jan. 31, 2001, now U.S. Pat. No.
6,543,842, which claims priority to and the benefit of U.S.
provisional patent application Ser. No. 60/180,417, entitled
FOLDING CHAIR WITH DOUBLE-WALLED SEAT, filed Feb. 3, 2000, each of
which is incorporated by reference.
BACKGROUND
[0002] 1. Field of the Invention
[0003] The present invention generally relates to chairs and, more
particularly, to a folding chair with armrests.
[0004] 2. Description of Related Art
[0005] Throughout history, people have sought more comfortable
seating arrangements. Chairs, stools, and the like allow people to
relieve stress on the legs and feet, while remaining alert and
performing tasks that do not require a great deal of motion. In the
twentieth century, folding chairs have made it possible for people
to keep a space clear when necessary, and to erect suitable seating
for gatherings or special events. However, current folding chairs
possess a number of drawbacks.
[0006] For example, folding chairs are often somewhat heavy. The
chair must reliably support the weight of even a fairly large
person. The bending stress on any member is proportional to the
length of the member multiplied by the force acting upon it.
Therefore, the length of the seat effectively multiplies the forces
tending to bend or break the seat. Typically, seats for folding
chairs have been made from stronger (and heavier) materials, such
as steel, to overcome the effect of these bending stresses. The
resulting chairs are heavier and therefore cost more to ship, and
require more effort to move, fold, and unfold.
[0007] Thus, it is desirable to use lightweight materials such as
plastics to reduce the weight of folding chairs. However, many
known folding chairs, especially those that incorporate lightweight
materials, do not stand up to repetitive use. Groups such as the
Business and Institutional Furniture Manufacturers' Association
(B.I.F.M.A.) have set up standards for portable furniture. Such
standards typically require that portable chairs be designed to
receive a given weight loading to simulate use for a specified
number of cycles, often on the order of 100,000. Many known folding
chairs bend or break after only a few thousand cycles, and
therefore can be expected to have a relatively short useful
life.
[0008] Certain known chairs use metal to reinforce lightweight
materials. The seat may, for example, be supported by a frame
encircling the seat or by metal rods threaded through the
lightweight material. In addition to increasing the weight of the
folding chair, such reinforcing measures add to manufacturing time
because the supporting structure must be properly aligned with the
seat, and possibly with the legs as well.
[0009] In general, many known folding chairs are somewhat expensive
to produce because the manner in which they are assembled requires
the use of a great deal of manual labor. The legs must often be
properly aligned with the seat so that mechanical fasteners can be
attached to the legs and the seat. If metal supporting parts are to
be threaded through the lightweight seat member to connect the
legs, the lightweight seat member may have to be aligned with each
leg assembly so that the threading operation can be carried out.
Often, the various fasteners involved must be installed at
locations that are not easily accessible for machinery. Thus, the
fasteners must often be installed by hand.
BRIEF SUMMARY OF THE INVENTION
[0010] A need therefore exists for a portable, folding chair that
is lightweight and comfortable, and yet folds to a thin, stackable
configuration.
[0011] One aspect of the invention is a folding chair with a chair
back and chair seat. A frame preferably connects the chair back and
chair seat. The frame is preferably constructed from metal and it
may be attached to the chair back and chair seat by one or more
fasteners. The chair seat and back may also be attached to the
frame by a friction, interference or snap fit connection.
[0012] Another aspect is a folding chair with a support bracket
that may be used to connect the chair seat to the frame. Desirably,
the support bracket is attached to the chair seat by an
interference fit. According to selected embodiments, the frame may
include a pair of symmetrical leg assemblies, each of which
includes a front leg and a rear leg. Each of the legs may have a
lower end in contact with the ground or floor, and an upper end
extending upward from the lower end. The seat may be suspended
between the leg assemblies. The upper end of the front legs may
also be extended to retain a backrest between the leg
assemblies.
[0013] A further aspect is the folding chair may include a seat
that is pivotally attached to the front leg and the rear leg of
each of the leg assemblies. Each of the leg assemblies may also
have a strut pivotally attached to the front leg and the rear leg,
so that the strut, front leg, rear leg, and seat form a four-bar,
four-pivot linkage. The chair may thus be folded by rotating the
seat with respect to the front legs, so that the seat and rear legs
fold into a position substantially parallel to the front legs.
[0014] Advantageously, the seat may comprise a lightweight seat
member constructed of a lightweight material, such as plastic, and
a pair of support brackets constructed of a stronger material such
as a metal. The lightweight seat member may be hollow and may be
formed through a suitable process such as injection molding, blow
molding or compression molding. Each support bracket may be
elongated in the longitudinal direction, with a generally enclosing
cross-sectional shape designed to grip the lightweight seat member
to restrict relative motion of the support bracket and lightweight
seat member perpendicular to the length of the support bracket. The
lightweight seat member may, in turn, have engaging features such
as a lateral ridge and a slot to receive each bracket. The
lightweight seat member may be generally configured to make contact
with each of the support brackets in several places so that lateral
and transverse relative motion of the lightweight seat member and
support brackets can be fully prevented.
[0015] Another aspect is the chair may include support brackets
that grip the seat with a retention force sufficient to ensure that
the support bracket cannot slide relative to the lightweight seat
member in the longitudinal direction during normal use of the
folding chair. To install the support brackets on the lightweight
seat member, each support bracket is preferably aligned with the
corresponding engaging features of the lightweight seat member and
pressed with an installation force similar in magnitude to the
retention force.
[0016] A further aspect is the chair may include support brackets
that have a tab designed to be bent into engagement with a
corresponding tab engagement slot formed in the lightweight seat
member after the support bracket has been properly positioned with
respect to the lightweight seat member. The tabs operate in
conjunction with the retention force of the support bracket to
ensure that the brackets cannot slide longitudinally off of the
seat.
[0017] Significantly, the folding chair maybe easily assembled. For
example, the leg assemblies can be assembled and then a support
bracket can be affixed to each leg assembly through the use of one
or more fasteners such as rivets, bolts, shafts with locking pins,
or the like. The backrest may be affixed to the legs by any
suitable fastening mechanism. The leg assemblies may then be
aligned relative to each other to receive the lightweight seat
member, and the lightweight seat member may be pressed into
engagement with the brackets.
[0018] Significantly, a minimum of metal material or components may
be used to affix the lightweight seat member to the leg assemblies.
In addition, no metal supports, such as rods or backing plates,
need be affixed to or threaded through the lightweight seat member.
Additionally, the seat member can be attached to the support
brackets without forming holes in the lightweight seat member;
thus, there are no stress concentrations to weaken the seat member
under repeated use. The folding chair can be easily assembled with
actions that can generally be performed rapidly by machine. One
skilled in the art will appreciate that one or more fasteners,
reinforcement structures and/or metal supports may also be used to
construct the chair, if desired.
[0019] Yet another aspect is a chair that may include one or more
armrests. The armrests are preferably securely connected to the
chair, but the armrests could be removably connected to the chair.
In addition, the armrests are preferably pivotally connected to the
chair, but the armrests could also be attached to the chair in a
fixed configuration. The armrests, for example, may be connected to
the legs of the chair. In particular, one armrest may be connected
to the first leg and another armrest may be connected to the second
leg. The armrests, however, could be attached to any suitable
portions of the chair. The armrests are preferably constructed from
a relatively strong material, such as metal, and the armrests
preferably have a length so that a user may comfortably place their
arms on the armrests while using the chair. It will be appreciated
that the armrests could be constructed from any materials with
suitable characteristics and properties, and the armrests could
have various desirable shape and configuration.
[0020] Still another aspect is a chair that may include armrests
that are movable between a use position and a storage position. The
chair is preferably a foldable chair that is movable between a use
position and a storage position. Advantageously, the movable
armrests and foldable chair may allow the chair to be easily stored
and transported. The chair may also include one or more stops or
protrusions that may be used to limit the movement of the armrests.
For example, a first stop or protrusion may help maintain an
armrest in the use position and a second stop or protrusion may be
used to help maintain the armrest in the storage position. The
stops or protrusions may include flanges or brackets that are sized
and configured to selectively engage the armrests in either the
first or second positions. The stops or protrusions could also
include one or more detents or other structures that are sized and
configured to limit the range of movement of the armrests. One
skilled in the art will appreciate that the stops and protrusions
may have a variety of suitable shapes and configurations.
[0021] A further aspect is a chair that may be moved between a use
position and a storage position and the chair include armrests that
are also movable between a use position and a storage position.
Advantageously, the armrests may include padding, cushioning,
guards and the like to, for example, increase the comfort of the
user. In particular, the armrests may include one or more layers of
material on at least a portion of the armrests. This may help
protect the armrests from damage and increase the potential uses of
the chair.
[0022] Advantageously, the armrests may increase the comfort and
possible uses of the chair. In addition, because the armrests may
be movable between first and second positions, the armrests do not
have to be used. Further, because the armrests may be used in
connection with a folding chair, the movable armrests may
facilitate shipping, transport and storage of the chair. The
armrests may also have a variety of suitable shapes and
configurations depending, for example, upon the type of chair
and/or intended use of the chair. One of ordinary skill in the art
will appreciate, however, that armrests are not required.
[0023] These and other aspects, features and advantages of the
present invention will become more fully apparent from the
following detailed description of preferred embodiments and
appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In order that the manner in which the above-recited and
other advantages and objects of the invention are obtained will be
readily understood, a more particular description of the invention
briefly described above will be rendered by reference to specific
embodiments thereof which are illustrated in the appended drawings.
Understanding that these drawings depict only typical embodiments
of the invention and are not therefore to be considered to be
limiting of its scope, the invention will be described and
explained with additional specificity and detail through the use of
the accompanying drawings in which:
[0025] FIG. 1 is a perspective view of one embodiment of a folding
chair with a lightweight seat member supported by interference fit
support brackets in accordance with the invention;
[0026] FIG. 2 is an exploded, perspective view depicting one
possible mode of the assembly of the folding chair of claim 1;
[0027] FIG. 3, is a bottom elevation view of the underside of the
lightweight seat member of FIG. 1;
[0028] FIG. 4 is a cutaway, sectioned view of part of the
lightweight seat member and one of the support brackets of FIG. 1,
depicting one possible manner in which the support a bracket may
engage the lightweight seat member;
[0029] FIG. 5 is an enlarged side view of a portion of the folding
chair of FIG. 1, illustrating an exemplary armrest in one position;
and
[0030] FIG. 6 is another side view of the portion of the folding
chair of FIG. 5, illustrating the armrest in another position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] The presently preferred embodiments of the present invention
will be best understood by reference to the drawings, wherein like
parts are designated by like numerals throughout. It will be
readily understood that the components of the present invention, as
generally described and illustrated in the figures herein, could be
arranged and designed in a wide variety of different
configurations. Thus, the following more detailed description of
the embodiments of the apparatus, system, and method of the present
invention, as represented in FIGS. 1 through 6, is not intended to
limit the scope of the invention, as claimed, but is merely
representative of presently preferred embodiments of the
invention.
[0032] Referring to FIG. 1, one embodiment of a folding chair 10
according to the invention is shown. The folding chair 10 has a
longitudinal direction 12, a lateral direction 14, and a transverse
direction 16. The folding chair 10 has a seat 18 designed to
comfortably support the weight of a user. The seat 18 may be
contoured as shown, with a recessed portion toward the middle to
distribute a user's weight evenly along the seat, thereby enhancing
the user's comfort. Preferably, the folding chair 10 has an
unfolded configuration, in which the seat 18 is horizontally
disposed at a height suitable for sitting, and a folded
configuration in which the folding chair 10 is more compact and
stackable.
[0033] The seat 18 may be supported by a first front leg 20, a
second front leg 22, a first rear leg 24, and a second rear leg 26.
Preferably, the legs 20, 22, 24, 26 are hollow so that higher
buckling resistance can be obtained without increasing the weight
of the legs 20, 22, 24, 26. The cross-sectional shape of the legs
20, 22, 24, 26 may be further modified to enhance buckling
resistance along the axis of greatest bending stress. For example,
the legs 20, 22, 24, 26 may have a generally elliptical
cross-section with the major (longer) axis oriented near the
longitudinal direction 12. Thus, the legs 20, 22, 24, 26 can be
fortified against bending moments occurring around the lateral
direction 14, as would be applied by a user sitting in the folding
chair 10.
[0034] The legs 20, 22, 24, 26 may be constructed of a relatively
strong, stiff material such as aluminum or steel. The legs 20, 22,
24, 26 may be surface hardened and made more resistant against
damaging environmental effects such as rust and ultraviolet
radiation through a method such as powder coating, in which a resin
or plastic powder is applied to the surface of the metal and then
heated to harden the surface.
[0035] The front legs 20, 22 may also be upwardly extended to
support a backrest 28 at a height comfortable for a user. The
backrest 28 may be contoured to comfortably fit the back of a user,
and may be constructed of a lightweight material such as plastic
with a hollow configuration to provide a larger sectional modulus
to enhance bending resistance. The backrest 28 may be manufactured
through a comparatively simple production process such as blow
molding, injection molding, or the like.
[0036] As depicted in FIG. 1, the first front leg 20 and the first
rear leg 24 are connected together to form a linkage. The first
front leg 20 and the first rear leg 24 may thus be collectively
referred to as a first leg assembly 30. Similarly, the second front
leg 22 and the second rear leg 26, together, form parallel linkage
that may be termed a second leg assembly 32. In FIG. 1, the leg
assemblies 30, 32 are shown on opposite lateral sides of the
folding chair 10. However, a folding chair according to the
invention could, for example, have symmetrical leg assemblies
disposed at the front and rear of the chair.
[0037] The front legs 20, 22 may each have a lower end 40 in
contact with flooring, pavement, or some other supporting surface,
and an upper end 42 extending above the seat 18 to receive the
backrest 28. Each of the front legs 20, 22 may also have an
intermediate portion 44 disposed generally between the lower end 40
and the upper end 42, at the approximate elevation of the seat 18.
Each of the rear legs 24, 26 may have a lower end 46 in contact
with a supporting surface and an upper end 48 at the approximate
elevation of the seat 18.
[0038] A front strut 50 may connect the first front leg 20 with the
second front leg 22, and a rear strut 52 may connect the first rear
leg 24 with the second rear leg 26. The front and rear struts 50
and 52 provide alignment and mutual support between the first and
second leg assemblies 30, 32. The legs 20, 22, 24, 26 and the
struts 50, 52 are preferably constructed of a stiff, strong
material such as steel, aluminum, or a composite.
[0039] The first front leg 20 may be connected to the first rear
leg 24 by a first link 60 pivotally attached to the first front leg
20 and to the first rear leg 24. Similarly, the second front leg 22
and the second rear leg 26 may be connected by a second link 62.
Thus, the first link 60 may be part of the first leg assembly 30,
and the second link 62 may be part of the second leg assembly 32.
The legs 20, 22, 24, 26 may be attached to the links 60, 62 by
fasteners 64 and to the seat 18 by fasteners 66, each of which
permits relative pivotal motion. Thus; each of the first and second
leg assemblies 30, 32 forms a four-bar, four-pivot linkage when
connected to the seat 18 to permit the rear legs 24, 26 and the
seat 18 to fold into a configuration substantially parallel to the
front legs 20, 22 and the backrest 28. Thus, the folding chair 10
may be folded and stored in are relatively compact fashion.
[0040] Referring to FIG. 2, an exploded view of the folding chair
10 of FIG. 1 is depicted, along with lines of assembly depicting
one suitable way to assemble the various parts of the folding chair
10. The seat 18 may include a lightweight seat member 72, a first
support bracket 74, and a second support bracket 76. The
lightweight seat member 72, like the backrest 28, is preferably
constructed of a lightweight, somewhat flexible material such as a
plastic.
[0041] Many manufacturing methods may be used to produce the
lightweight seat member 72. For example, top and bottom portions of
the lightweight seat member 72 may be constructed separately,
through stamping, injection molding, or other simple processes, and
then attached together. The top and bottom portions may be attached
by molding fasteners into the parts, using separate fasteners, or
joining the parts using a heat-based technique such as welding.
Other processes, such as tumble molding, roller molding, and blow
molding may also be utilized to create the seat 12 as a single
unitary piece. Blow molding is presently preferred.
[0042] The novel construction of the folding chair 10 is especially
well-adapted for use with a lightweight seat member 72 constructed
of such a lightweight material because the lightweight seat member
72 can be attached to the folding chair 10 in a way that does not
subject the lightweight seat member 72 to highly-localized
stresses. Plastics generally have a much lower yield point (maximum
stress before permanent deformation occurs) than metals.
Additionally, plastics tend to experience "creep," or permanent
deformation over prolonged loading, at comparatively low stresses.
Consequently, it is important to ensure that no part of the
lightweight seat member will be subjected to high or prolonged
stresses.
[0043] A number of features found in known chair seats tend to
concentrate stresses at parts of the seat that could later become
failure points in a seat constructed of weaker, lightweight
material. For example, many chairs have fasteners that must be
inserted through holes formed in the lightweight seat member. Any
hole in a load-bearing member has a smaller cross-section than
adjacent regions. Since stress is defined as force (tensile,
compressive, or shear) divided by the area of material across which
the force acts, the smaller area surrounding the hole is subjected
to increased stresses as a result of the hole. Thus, holes, narrow
regions, shelves, and the like are referred to in the art as
"stress concentrations" or "stress risers."
[0044] The effect of such stress concentrations is multiplied by
the nature of the loading applied to the lightweight seat member. A
typical user will not simply sit still in a chair for a lengthy
period of time; rather, most users will move considerably and shift
their weight from one portion of the chair to another. Thus, the
lightweight seat member is subjected to "fatigue" loading, or
stress that increases, decreases, or even changes direction (from
tensile to compressive or from compressive to tensile) many times
during the life of the chair. Fatigue loading conditions accelerate
the deformation and eventual failure of materials, especially those
with a comparatively high degree of ductility, such as
plastics.
[0045] In the case of a fastener threaded through a plastic hole,
the result is that the hole will be gradually widened by pressure
against the fastener over time, so that more and more play, or
"slop," is present in the folding chair. Finally, the hole may fail
to retain the fastener altogether, and the chair may collapse as a
result. Other forms of attachment may similarly concentrate
stresses that tend to cause accelerated failure in a plastic seat
member.
[0046] The support brackets 74, 76 of the present invention
represent a significant improvement over the prior art because they
are attached to the lightweight seat member 72 in such a way that
stresses are relatively evenly spread over the lightweight seat
member 72 when the folding chair 10 is in use. According to certain
embodiments, the support brackets 74, 76 provide such an even
distribution of stresses through an interference fit engagement
with lightweight seat member 72 that will be described in further
detail subsequently.
[0047] Each of the support brackets 74, 76 may have a front end 77,
a rear end 78, and an intermediate portion 79. The fasteners 64, 66
used to attach the leg assemblies 30, 32 to the struts 60, 62 and
the support brackets 74, 76 may have a wide variety of
configurations including screws, bolts, nuts, rivets, clips,
clamps, shafts with locking pins, or the like. As depicted in FIG.
2, each of the fasteners 64, 66 comprises a rivet. Generally, each
of the rivets 64, 66 may have a button 80 affixed to a shank 82
sized somewhat narrower than the button 80. Each of the rivets 64,
66 may also have a cap 84 configured to fit onto the shank 82 and
to be compressed for permanent attachment to the shank 82 by a
method such as crimping.
[0048] Each of the legs 20 22, 24, 26 may have a hole 86 sized to
receive a shank 82 of a rivet 64 for pivotal attachment to one of
the links 60, 62. Similarly, each of the legs 20, 22, 24, 26 may
have a hole 88 sized to receive a shank 82 of a rivet 66 for
pivotal attachment to one of the support brackets 74, 76. Each of
the support brackets 74, 76 may have a rear hole 90 surrounded by a
rear indentation 92 and a front hole 94 surrounded by a front
indentation 96. The indentations 92, 96 are preferably each shaped
to contain a button 80 of a rivet 66. Thus, the buttons 80 can be
retained on the inside of the support brackets 74, 76 without
protruding inward to interfere with the lightweight seat member
72.
[0049] Preferably, the shanks 82 of the rivets 64, 66 fit with
clearance through the holes 86, 88, 90, 94 to permit free relative
rotation. Additionally, the buttons 80 and caps 84 of the rivets
64, 66 should be sized too large to fit through the holes 90, 94
and 86, 88, respectively, so that the rivets 64, 66 are unable to
slip out of the holes 86, 88. The legs 20, 22, 24, 26 may each have
an alcove 97 facing inward and located toward the first end 40, 46
into which the struts 50, 52 can be inserted. If desired, the
struts 50, 52 may be welded, crimped, or otherwise affixed in place
within the alcoves 97 to fix the displacement of the leg assemblies
30, 32 with respect to each other. The backrest 28 may also bridge
the gap between the first and second leg assemblies 30, 32 upper
ends 42 of which may be attached to mating surfaces 98 of the
backrest 28.
[0050] Each of the support brackets 74, 76 may have a tab 99
configured to lock the lightweight seat member 72 into place once
installed within the support brackets 74, 76. The tab 99 preferably
comprises a rectangular portion of each of the support brackets 74,
76, three sides of which have been cut through so that the tab 99
can be lifted by folding the tab 99 along the remaining side of the
rectangle. The tabs 99 may be preformed in a bent position, and may
flex upon contact with the lightweight seat member 72 and snap into
place within grooves of the lightweight seat member 72, which will
be depicted subsequently. The tabs 99 may alternatively be formed
in a straight position and bent into engagement after installation
on the lightweight seat member 72.
[0051] The support brackets 74, 76 are preferably made of a
comparatively stiff, strong metal such as aluminum or steel. The
support brackets 74, 76 may also be surface treated by a method
such as powder coating, like the legs 20, 22, 24, 26. Pre-flexing
of the tabs 99 helps to prevent cracking of the tabs 99 when they
are bent during assembly.
[0052] The lightweight seat member 72 may generally have a first
side 100 disposed near the first leg assembly 30, and a second side
102 disposed near the second leg assembly 32. Additionally, the
lightweight seat member 72 may have a front surface 104, a rear
surface 106, a top surface 108, and a bottom surface 110. A lateral
ridge 120 maybe formed each of the first and second sides 100, 102.
Each lateral ridge 120 may comprise a longitudinally elongated
bulge with a lateral engagement surface 122, an engagement groove
124, and an abutment 126. The lateral engagement surface 122 is
preferably oriented substantially perpendicular to the lateral
direction 14. Preferably, each of the lateral ridges 120 has a
substantially uniform cross-sectional shape, as viewed along the
longitudinal direction 12, so that the lateral ridges 120 engage
the support brackets 74, 76 uniformly along their length.
[0053] The engagement groove 124 may take the form of a trough
extending downward and inward, running along the top of each
lateral ridge 120. Each of the abutments 126 may simply consist of
a rearward-facing portion material jutting outward from each
lateral ridge 120. The abutments 126 serve to limit motion of the
support brackets 74, 76 over the lateral ridges 120 to ensure that
the support brackets 74, 76 do not slide too far with respect to
the lightweight seat member 72.
[0054] The backrest 28 may be attached to the upper ends 42 of the
front legs 20, 22, for example, through the use of studs 128
affixed to the mating surfaces 98 of the backrest 28. The studs 128
may be generally mushroom-shaped, with an enlarged head atop a
narrower stem. Corresponding keyholes 130 may be formed in the
upper ends 42 of the front legs 20, 22 to receive the studs 128.
Each of the keyholes 130 may generally have a larger opening into
which a head of a stud 128 can pass with clearance, and a slot
configured to receive the stem of the stud 128 when the backrest 28
is pressed downward with respect to the front legs 20, 22. Other
fastening techniques, such as thermal, radio frequency, or
frictional welding, chemical or adhesive bonding, or the like may
be utilized to ensure that the studs 128 remain firmly installed
within the keyholes 130.
[0055] Referring to FIG. 3, the bottom surface 110 of the
lightweight seat member 72 is depicted. Each of the lateral ridges
120 may have a transverse engagement surface 140 facing generally
downward. Slots 142 may run parallel to the lateral ridges 120 to
provide tighter engagement of the support brackets 74, 76. The
slots 142 may simply take the form of rectangular recesses
extending longitudinally along the bottom surface 110. A tab
engagement slot 144, in the form of a roughly rectangular
indentation, may be formed in each of the transverse engagement
surfaces 140 to receive the tabs 99.
[0056] The bottom surface 110 may also have a plurality of troughs
150 oriented in the lateral direction 14. The troughs 150
preferably do not extend upward far enough to contact the top
surface 108 of the lightweight seat member 72. The troughs 150
serve to increase the section modulus of the lightweight seat
member 72 by providing transversely-oriented, or substantially
vertically-oriented sections of material that do not bend easily
about the longitudinal axis 12. Thus, the lightweight seat member
72 resists bending in a way that would tend to raise or lower the
first and second sides 100, 102 of the lightweight seat member 72
with respect to the remainder of the lightweight seat member 72.
The troughs 150 may, also provide handholds for a user so that the
chair 10 can easily be folded, unfolded, and carried by a user.
[0057] In embodiments in which the lightweight seat member 72 is
hollow, as with a blow-molded lightweight seat member 72,
kiss-throughs 152 may be formed within the troughs 150 to connect
the top and bottom surfaces 108, 110 of the lightweight seat member
72. The kiss-throughs 152 keep the top surface 108 from being
pressed into the hollow interior of the lightweight seat member 72
under a user's weight. However, the kiss-throughs 152 may be
positioned around the center of the lightweight seat member 72 to
permit slight deformation so that the lightweight seat member 72
has a somewhat soft feel. Styling lines 154 may also be provided in
the bottom surface 110 of the lightweight seat member 72 to add
aesthetic to the chair 10 in the folded configuration. An injection
hole 156 may remain in the bottom surface 110 where a nozzle was
inserted into a mold to inject air.
[0058] The kiss-throughs 152 and the troughs 150, as depicted in
FIG. 3, have been arranged to increase the structural rigidity and
overall strength of the lightweight seat member 72. Although other
configurations may be used, the embodiment depicted in FIG. 3 is
presently preferred because it provides good support while adding a
minimum of material to the seat 72. Consequently, the overall
weight of the folding chair 10 is kept at a minimum.
[0059] Referring to FIG. 4, a sectioned view of a portion of the
seat 18, including the first side 100 of the lightweight seat
member 72 and the first support bracket 74, is depicted, taken from
behind the seat 18. The support brackets 74, 76 preferably have a
cross-sectional shape configured to interlock with the lightweight
seat member 72 to restrict motion parallel to the cross-section (in
the lateral or transverse directions 14, 16). More specifically,
the support brackets 74, 76 preferably have an enclosing
cross-sectional shape. An "enclosing" cross sectional shape is a
shape in which an opening of the cross section is narrower than the
widest expanse of a structure, parallel to the opening, that can be
contained within the cross section. An enclosing structure with a
shape conforming generally to the enclosing shape is therefore
unable to escape through the opening.
[0060] Although the enclosing shape is one preferred method of
obtaining interlocking between the support brackets 74, 76 and the
lightweight seat member 72, the support brackets 74, 76 need not
have an enclosing shape to engage the lightweight seat member 72 in
interlocking fashion. The support brackets 74, 76 may, for example,
have outwardly extending edges (not shown) engaged within
corresponding slots or grooves of the lightweight seat member
72.
[0061] As shown in FIG. 4, the first bracket 74 preferably takes
the form of an L-shaped member with lips extending toward the
interior of the L to form an enclosing shape. More specifically,
the first support bracket 74 may have a supporting flange 160
positioned underneath the transverse engagement surface 140 of the
lightweight seat member 72. The supporting flange 160 may simply
comprise a comparatively flat piece of material perpendicular to
the transverse direction 16, extending along the length of the
lightweight seat member 72 in the longitudinal direction 12. An
attachment flange 162 may extend in a substantially transverse
direction from the supporting flange 160 to cover the lateral
engagement surface 122 of the lateral ridge 120, and may also
extend along the length of the lightweight seat member 72 in the
longitudinal direction 12. Thus, the attachment flange 162 is
preferably substantially perpendicular (at a near 90.degree. angle)
to the support flange 160.
[0062] Furthermore, an upper lip 164 may extend inward from the
attachment flange 162 and into the engagement groove 124. The upper
lip 164 may advantageously form an acute angle with respect to the
attachment flange 162 so that the attachment flange 162 extends
both inward and downward to grip the edges of the engagement groove
124. The upper lip 164 may, for example, be positioned at a
40.degree. to 60.degree. angle with respect to the attachment
flange 162. An angle of 50.degree. may be preferred. A lower lip
166 may extend upward, substantially perpendicular to the
supporting flange 160 to engage the slot 142.
[0063] Between the lips 164, 166 of the cross-section, an opening
exists in the cross-sectional shape of the first support bracket
74. Since the lips 164, 166 are directed generally inward, the
opening is not large enough to permit the first support bracket 74
to slip out of engagement with the lightweight seat member 72 in
the lateral or transverse directions 14, 16. Consequently, the
cross-sectional shape of the first support bracket 74, as embodied
in FIG. 4, is enclosing.
[0064] Although the L-shape depicted in FIG. 4 is preferred, the
cross-section of the support brackets 74, 76 may have any other
suitable enclosing or partially-enclosing shape, such as a C-shape.
Alternatively, the support brackets 74, 76 need not have an
enclosing shape, and the sides 100, 102 of the lightweight seat
member 72 may instead each have an enclosing shape configured to
hold the support brackets 74, 76 in place. The configuration of
FIG. 4 may, however, have significant manufacturing benefits over
these alternatives.
[0065] The enclosing cross-sectional shape shown in FIG. 4 provides
counterbalancing forces in both the lateral direction 14 and the
transverse direction 16 to prevent relative motion between the
first support bracket 74 and the lightweight seat member 72 in
those directions. The supporting flange 160, the attachment flange
162, the upper lip 164, and the lower lip 166 need not contact the
lightweight seat member 72 uniformly across an entire surface to
provide those counterbalancing forces. If desired, the lightweight
seat member 72 may instead contact: each of the flanges 160, 162
and the lips 164, 166 at a contact point extending in the
longitudinal direction 12 along the length of the first support
bracket 74.
[0066] For example, the supporting flange 160 may contact the
bottom surface 110 of the lightweight seat member 72 at a first
contact point 170. The attachment flange 162 may contact the
lateral engagement surface 122 at a second contact point 172.
Similarly, the second lip 166 may contact the slot 142 at a third
contact point 174, and the first lip 164 may contact the engagement
groove 124 at a fourth contact point 176. At each of the contact
points 170, 172, 174, 176, the first support bracket 74 may exert a
force against the lightweight seat member 72 perpendicular to the
surface of the first support bracket 74 at which the contact point
170, 172, 174, 176 exists.
[0067] Thus, a first restraining force 180 may be applied by the
supporting flange 160 at the first contact point 170, in an upward
direction, perpendicular to the supporting flange 160. The second,
third, and fourth contact points 172, 174, 176 may each have an
associated restraining force 182, 184, 186 perpendicular to the
attachment flange 162, the lower lip 166, and the upper lip 164,
respectively.
[0068] The second restraining force 182 acts inward along, the
lateral axis 14, and the third restraining force 184 acts outward
along the lateral axis 14 to oppose the second restraining force
182. The fourth restraining force 186 also has a component lying
along the lateral axis 14 that resists the second restraining force
182. Similarly, the first restraining force 180 is pressed upward
along the transverse axis 16, and the fourth restraining force 186
has a component along the transverse axis 16 that presses downward
to oppose the first restraining force 180. The restraining forces
180, 182, 184, 186 act to keep the first support bracket 74 and the
lightweight seat member 72 in static equilibrium with respect to
the lateral and transverse directions 14, 16. Thus, relative motion
between the first support bracket 74 and the lightweight seat
member 72 in any direction within the plane formed by the lateral
and transverse directions 14, 16 is restricted.
[0069] The restraining forces 180, 182, 184, 186 also restrain
relative motion between the first support bracket 74 and the
lightweight seat member 72 in the longitudinal direction 12. When
two objects are in contact with one another, static friction tends
to keep them from moving relative to each other in a direction
parallel to the surfaces at which contact exists. Static friction
is generally proportional to the normal force, or force pressing
the objects together, and the frictional coefficient, which is
related to the size and roughness of the contacting surfaces. The
restraining forces 180, 182, 184, 186 therefore produce a
frictional force acting to resist relative motion in the
longitudinal direction 12.
[0070] Preferably, the frictional force is large enough to resist
relative motion of the support brackets 74, 76 and the lightweight
seat member 72, even if the tabs 99 are somehow disengaged from the
tab engagement slots 144. However, the frictional force is
preferably not so great that insertion of the lightweight seat
member 72 in engagement with the brackets 74, 76 is made overly
difficult. Thus, the geometries of the lightweight seat member 72
and the brackets 74, 76 are preferably designed to ensure that the
restraining forces 180, 182, 184, 186 have a magnitude that will
induce the appropriate level of frictional force.
[0071] The frictional force may also be modified by adjusting the
contact points 170, 172, 174, 176 to create larger or smaller
surface areas in contact with each other. Additionally, the
frictional force may be adjusted by increasing or decreasing the
surface roughness of the lateral ridge 120 and/or the support
brackets 74, 76. The application of frictional force to keep the
support brackets 74, 76 attached to the lightweight seat member 72
may be referred to as "engagement," or "gripping engagement." The
force required to produce engagement between the support brackets
74, 76 and the lightweight seat member 72 is the "engagement
force."
[0072] Typically, the "disengagement force," or force required to
disengage the support brackets 74, 76 from the lightweight seat
member 72 (with the tabs 99 disengaged), will be about the same as
the engagement force. The disengagement force may even be somewhat
greater, than the engagement force because the disengagement force
must overcome the static friction between the support brackets 74,
76 and the lightweight seat member 72. The static friction is
typically larger than the dynamic friction that resists the
engagement force.
[0073] The restraining forces 180, 182, 184, 186 enable the support
brackets 74, 76 to grip the lightweight seat member 72 without the
use of mechanical fasteners. "Mechanical fasteners," as used in
this application, refers to rigid devices used to connect two
separate members together. Thus, screws, nuts, bolts, rivets,
locking pins, and the like are all mechanical fasteners. However,
non-rigid attachment mechanisms, such as glues, epoxies, and the
like, are not mechanical fasteners.
[0074] The first support bracket 74 would still have an enclosing
shape if the upper lip 164 were perpendicular to the attachment
flange 162. However, the acute angle of the upper lip 164, as
depicted, may provide a more lasting engagement between the first
support bracket 74 and the lightweight seat member 72.
[0075] More specifically, with brief reference to FIG. 1, a user
sitting toward the front surface of the lightweight seat member 72
of the folding chair 10 may induce a bending moment in the seat 18
that must be resisted by the rivet 66 connecting the first support
bracket 74 to the first rear leg 24. Thus, the rivet 66 may pull
downward on the rear end 78 of the first support bracket 74 to
resist the downward force of the user against the forward part of
the seat 18. The rear end 78 of the first support bracket 74, in
return, pulls downward against the lateral ridge 120 of the
lightweight seat member 72. As a result, the upper lip 164 is
pressed into the engagement groove 124. This pressure tends to
resist inward pivoting of the walls of the engagement groove 124
that may result in bending of the lightweight seat member 72 under
a user's weight.
[0076] If the angle between the upper lip 164 and the attachment
flange 162 were formed or bent into an obtuse configuration, the
pressure between the upper lip 164 and the sides of the engagement
groove 124 would tend to bend the upper lip 164 further, bend the
attachment flange 162 outward, and/or deform the lateral ridge 120
inward. As a result, the upper lip 164 maybe moved sufficiently in
the lateral direction 14 with respect to the engagement groove 124
to disengage the upper lip 164 from the engagement groove 124. The
probable result of such disengagement would be failure of the
folding chair 10 due to complete disengagement of the lightweight
seat member 72 from the first support bracket 74, extreme
deformation of the lightweight seat member 74, or the like.
[0077] As a result of the acute angle, pressure of the sides of the
engagement groove 124 upward against the upper lip 164 is directed
toward the point at which the upper lip 164 meets the attachment
flange 162. Thus, the moment arm tending to bend the upper lip 164
upward is reduced, and the upper lip 164 is drawn inward into
tighter engagement with the engagement groove 124. Consequently,
with the acute angle, the weight of a user on the seat 18 tends to
simply tighten the engagement of the upper lip 162 of the rear end
78 of the first support bracket 74 within the engagement groove
124.
[0078] Preferably, each of the support brackets 72, 74 comprises an
arcuate shape in the longitudinal direction 12, as shown in FIGS. 1
and 2. An "arcuate" shape refers to a member formed into an overall
curve with a substantially constant radius along the entire length
of the member. Preferably, the lateral ridge 120 has an arcuate
shape with a radius substantially equal to that of the first
support bracket 74. The arcuate shape is beneficial because it
discourages bending of the support brackets 74, 76 without adding a
great deal of material.
[0079] In effect, the arcuate shape increases the sectional modulus
of the support brackets 74, 76 by displacing material from the
longitudinal axis of the support brackets 74, 76. More
specifically, the front and rear ends 77, 78 of the support
brackets 74, 76 are raised up with respect to the intermediate
portion 79. The intermediate portion 79 lies generally below the
longitudinal axis of the support brackets 74, 76, while the ends
77, 78 are positioned above the longitudinal axis. Thus, the
support brackets 74, 76 have a much higher sectional modulus with
the arcuate shape than a straight shape would provide. Bending of
the seat 18 in the longitudinal direction 12, or from
front-to-back, is therefore resisted.
[0080] The support brackets 74, 76 may be easily manufactured
through a number of different process including extrusion,
stamping, casting, and the like. According to a preferred method, a
large, circular piece of metal is first punched out and separated
into arcuate sections in a die, such as a 14 station die. Each
arcuate section may then be bent to form the L-shape depicted in
FIG. 14, and bent again to form each of the lips 164, 166. Bending
may be performed against a circular edge so that the arcuate shape
of each section is preserved.
[0081] With reference again to FIG. 2, the folding chair 10 may be
assembled comparatively easily, with a minimum of manual labor.
According to one presently preferred method of assembly, the first
and second leg assemblies 30, 32 are first assembled. Thus, the
first front leg 20 and the first rear leg 24 may, each be pivotally
connected to the first link 60 with the rivets 64, and pivotally
connected to the first support bracket 74 with the rivets 66 to
form the first leg assembly 30. The second leg assembly 32 may be
similarly created by pivotally connecting the second front leg 22
and the second rear leg 26 to the second link 62 with the rivets
64, and to the second support bracket 76 with the rivets 66.
[0082] Once the leg assemblies 30, 32 have been assembled, the
front and rear struts 50, 52 may be affixed within the alcoves 97
to attach the leg assemblies 30, 32 together. The backrest 28 may
then be inserted between the upper ends 42 of the front legs 20, 22
by bending the upper ends 42 outward slightly in the lateral
direction 14, if necessary. The backrest 28 may be fixed in place
between the upper ends by inserting the studs 128 into the keyholes
130, and then pressing the backrest 28 downward so that the studs
128 are engaged within the slots of the keyholes 130.
[0083] If desired, the lightweight seat member 72 maybe installed
last. The support brackets 74, 76 maybe rotated into a suitable
position to receive the lightweight seat member 72, and then the
lightweight seat member 72 may be aligned with the support brackets
74, 76 so that the lateral ridge 120 is positioned to enter the
front end 77 of the first support bracket 74. Pressure may then be
applied against the lightweight seat member 72 by, for example,
pressing against the front surface 104 to slide the lightweight
seat member 72 into engagement with the support brackets 74, 76.
The pressure may be applied continuously until the front end 77 of
the brackets 74, 76 abuts the abutment 126 on the first and second
sides 100, 102 of the lightweight seat member 72.
[0084] Pressure may be applied against the lightweight seat member
72 by hand, or by using a machine. For example, a simple press (not
shown) may be configured to exert pressure against the front
surface 104 or grip the lightweight seat member 72 for insertion
into the support brackets 74, 76. As long as the support brackets
74, 76 and the lightweight seat member 72 are consistently
manufactured from one chair to the next, the press may be
configured to provide a preset pressure against the lightweight
seat member 72. This pressure may, for example, range from about 10
pounds to about 1,000 pounds. Preferably, the pressure is
relatively low, such as 50 pounds, so that the probability of
damaging any part of the folding chair 10 through malfunction of
the press or improper dimensioning or alignment of the lightweight
seat member 72 or support brackets 74, 76 is low. The pressure may
be applied continuously, and may be varied to move the lightweight
seat member 72 in an arcuate path corresponding to its longitudinal
shape.
[0085] After the abutments 126 of the lightweight seat member 72
are seated against the front ends 77 of the support brackets 74,
76, pressure need no longer be applied. Since the tabs 99 are
aligned with the tab engagement slots 144, they will snap into
engagement with the tab engagement slots 144 as they return to
their preformed, bent position. In the alternative, if the tabs 99
were formed parallel to the supporting flange 160, the tabs 99 may
be folded into position within the tab engagement slots 144. The
tabs 99 may not be necessary to keep the lightweight seat member 72
securely engaged within the support brackets 74, 76, but may be
used in any case to provide an added measure of safety under
abnormal usage conditions.
[0086] Such a method of assembly alleviates problems present in the
prior art. There are no supporting structures extending from one
side of the lightweight seat member 72 to the other. For example,
instead of long front and tear thru-rods, separate rivets 64, 66
for each side are used to connect the leg assemblies 30, 32 to the
seat 18. This permits assembly of the folding chair 10 without the
problem of aligning the leg assemblies 30, 32 with the single rod.
In addition, the absence of any horizontal rods extending through
the hollow interior of the lightweight seat member 72 is beneficial
because supporting structures, such as the troughs 150 and
kiss-throughs 152 shown in FIG. 3, may be formed directly in the
material of the lightweight seat member 72 without interference
from foreign structures inside the lightweight seat member 72. The
absence of any type of metal plate spanning the width of the
lightweight seat member 72 serves to decrease the weight of the
folding chair 10.
[0087] Additionally, the interference fit configuration of the
present invention is beneficial because the lightweight seat member
72 is securely supported in a way that distributes stresses
comparatively evenly to avoid creating failure points. The unique
shape of the support brackets 74, 76 also supports the lightweight
seat member 72 against bending with the addition of a minimal
amount of heavier material so that the overall weight of the
folding chair 10 is kept to a minimum. Thus, the folding chair 10
of the present invention is generally inexpensive, easy to
manufacture, lightweight, easy to use, and comfortable.
[0088] As shown in FIGS. 1-6, the chair 10 may include one or more
armrests, such as armrests 200a, 200b. The armrests 200a, 200b are
preferably connected to a frame connecting the chair back and chair
seat and, in particular, to the legs 20, 22, respectively.
Desirably, the armrests 200a, 200b are pivotally connected to the
frame so that the armrests can be moved between a use position and
a storage position. For example, the armrests 200a, 200b may
respectively include a hole or aperture 202a, 202b sized configured
to receive a fastener 204a, 204b to pivotally connect the armrests
to the legs 20, 22; and the legs 20, 22 may respectively include a
hole or aperture 206a, 206b sized and configured to receive the
fasteners 204a, 204b. The fasteners 204 may comprise a pin, a
rivet, a bolt, a screw, a nail, or other suitable fasteners or
connectors. A washer 208a, 208b may be used to help connect the
armrests 200a, 200b to the legs 20, 22. The armrests 200a, 200b,
however, do not have to be pivotally connected to the frame and the
armrests can be connected to any suitable portion of the chair
10.
[0089] The armrests 200a, 200b are preferably constructed from a
relatively strong material, such as metal, and the armrests
preferably have a generally tubular configuration. As shown in
FIGS. 1-6, the armrests 200a, 200b preferably include a generally
oblong shape with a pair of opposing generally flat portions and a
pair of opposing generally rounded portions. Advantageously, the
generally flat portions and/or the generally rounded portions may
help to provide a more comfortable armrest. In one embodiment, one
or more portions of the arm rests 200a, 200b may be constructed
from plastic, such as high density polyethylene, using a
blow-molding process, a rotary-molding molding process, an
injection-molding process, an extrusion-molding process, or other
suitable process. The armrests 200a, 200b, however, could be
constructed from other processes using any materials with suitable
characteristics and properties, and the armrests could have any
desirable shape and configuration.
[0090] The armrests 200a, 200b are preferably movable among a
plurality of positions, including a use position and a storage
position. In one embodiment, the movement of the armrests 200a,
200b may be limited to a particular range of motion by, for
example, one or more stops or protrusions. For example, a first
stop or protrusion 210a may help maintain the armrest 200a in the
use position as shown in FIG. 5, and a second stop or protrusion
212a may be used to help maintain the armrest 200a in the storage
position as shown in FIG. 6. Likewise, a first stop or protrusion
210b may help maintain the armrest 200b in the use position, and a
second stop or protrusion 212b may be used to help maintain the
armrest 200b in the storage position. When in the storage position,
the armrests 200a, 200b are preferably generally aligned with the
legs 20, 22, which helps to prevent the armrests from being
obstructions. The stops or protrusions 210, 212 may include flanges
or brackets that are sized and configured to selectively engage the
armrests in the first or second positions. The stops or protrusions
210, 212 could also include one or more detents or other structures
that are sized and configured to limit the range of movement of the
armrests 200a, 200b. As shown in FIGS. 1-6, brackets 214a, 214b may
include the stops or protrusions 210a,. 210b, 212a, and 212b, and
the brackets may be connected to the legs 20, 22 using the
fasteners 204a, 204b and 216a, 216b. Thus, the stops or protrusions
210,. 212 may be connected to the legs 20, 22, but the stops or
protrusions may be formed integrally with the legs as part of a
unitary, one-piece construction. Also, the stops and protrusions
210, 212 may have a variety of other suitable shapes and
configurations. Further, the chair 10 does not require any stops
and protrusions, and the movement of the armrests 200a, 200b need
not be limited.
[0091] The armrests 200a, 200b may include padding or cushioning to
increase the comfort of the user. For example, the armrests 200a,
200b may include one or more layers of material on at least a
portion of the armrests. Preferably, the padding or cushioning
still allows the armrests to move relative to the chair, but it
will be appreciated that the armrests could be secured in a fixed
position.
[0092] Advantageously, the armrests may increase the comfort and
possible uses of the chair. In addition, because the armrests may
be movable between first and second positions, the armrests do not
have to be used. Further, the armrests and folding chair may
facilitate stacking, storage, shipping and transport of the chair.
One skilled in the art will appreciate, however, that the chair
does not require armrests.
[0093] The present invention may be embodied in other specific
forms without departing from its structures, methods, or other
essential characteristics as broadly described herein and claimed
hereinafter. The described embodiments are to be considered in all
respects only as illustrative, and not restrictive. The scope of
the invention is, therefore, indicated by the appended claims,
rather than by the foregoing description. All changes that come
within the meaning and range of equivalency of the claims are to be
embraced within their scope.
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