U.S. patent application number 14/589354 was filed with the patent office on 2016-04-28 for sturdy, compact, collapsible camping chair.
The applicant listed for this patent is FIMAX International Co., Ltd. Invention is credited to Youn Jae Lee.
Application Number | 20160113402 14/589354 |
Document ID | / |
Family ID | 55790945 |
Filed Date | 2016-04-28 |
United States Patent
Application |
20160113402 |
Kind Code |
A1 |
Lee; Youn Jae |
April 28, 2016 |
Sturdy, Compact, Collapsible Camping Chair
Abstract
A collapsible chair includes upper tubes, leg tubes, a central
tube connector and a seat back. The tube connector has two first
tubes bent around a central cylinder from below and two second
tubes bent around the central cylinder from above. The first and
second tubes are welded to the central cylinder. Upper holes are
formed by the ends of the first tubes, and lower holes are formed
by the ends of the second tubes. Lower ends of the upper tubes are
inserted into the upper holes, and upper ends of the leg tubes are
inserted into the lower holes. Upper ends of the upper tubes fit
into tube receptacles in the seat back. No part of the upper tubes
other than the upper and lower ends contacts any part of the chair.
The two back upper tubes are bent and are longer than the two
straight front upper tubes.
Inventors: |
Lee; Youn Jae; (Pleasanton,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FIMAX International Co., Ltd |
Seoul |
|
KR |
|
|
Family ID: |
55790945 |
Appl. No.: |
14/589354 |
Filed: |
January 5, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
29507520 |
Oct 28, 2014 |
|
|
|
14589354 |
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Current U.S.
Class: |
297/16.2 ;
29/428; 297/440.11 |
Current CPC
Class: |
A47C 4/42 20130101; A47C
1/14 20130101; A47C 9/10 20130101; A47C 9/105 20130101; A47C 4/02
20130101; A47C 4/30 20130101 |
International
Class: |
A47C 4/42 20060101
A47C004/42; A47C 4/30 20060101 A47C004/30; A47C 1/14 20060101
A47C001/14 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 18, 2014 |
KR |
2020140008443 |
Claims
1. A collapsible chair comprising: upper tubes with lower ends and
seat ends, wherein the lower ends have circular cross setions; leg
tubes with upper ends; a seat back with tube receptacles; a central
cylinder; two first short bent tubes that bend around the central
cylinder from below and that are welded to the central cylinder,
wherein four upper holes with circular circumferences are formed at
ends of the first tubes; and two second short bent tubes that bend
around the central cylinder from above and that are welded to the
central cylinder, wherein four lower holes with circular
circumferences are formed at ends of the second tubes, wherein the
lower ends of the upper tubes are detachably connected to the first
bent tubes by being inserted into the upper holes, wherein the
upper ends of the leg tubes are detachably connected to the second
bent tubes by being inserted into the lower holes, wherein the seat
ends of the upper tubes are detachably connected to the tube
receptacles, and wherein no part of the upper tubes other than the
lower ends and the seat ends contacts any part of the collapsible
chair.
2. The collapsible chair of claim 1, wherein the upper tubes
consist of two tubes of a first length and two tubes of a second
length, and wherein the first length is longer than the second
length.
3. The collapsible chair of claim 2, wherein each of the two tubes
of the first length is bent, and wherein neither of the two tubes
of the second length is bent.
4. The collapsible chair of claim 2, wherein each of the upper
tubes of the first length has a lower section, a middle section and
an upper section, wherein the lower end of each upper tube of the
first length is disposed on the lower section of the upper tube,
wherein each lower section is curved, and wherein each middle
section and each upper section is straight.
5. The collapsible chair of claim 1, wherein the central cylinder
has a diameter that is larger than the diameter of the upper
tubes.
6. The collapsible chair of claim 1, wherein each of the upper
tubes is comprised of detachable sections.
7. The collapsible chair of claim 1, wherein the circular cross
section of each of the lower ends is dimensioned to fit snugly into
the circular circumference of a corresponding upper hole.
8. The collapsible chair of claim 1, wherein the upper tubes
consist of four tubes, and wherein the seat ends fit into the tube
receptacles at four corners of the seat back.
9. The collapsible chair of claim 1, wherein the seat back is made
of fabric.
10. The collapsible chair of claim 1, further comprising: an
elastic cord that passes through one of the first short bent tubes
and into one of the upper tubes.
11. A collapsible chair comprising: a seat back with tube
receptacles; and a frame made of metal tubes, wherein the frame
comprises: upper tubes with lower ends and seat ends, wherein the
lower ends have circular cross sections; a central tube whose
diameter is larger than that of the upper tubes; and means for
forming upper holes with circular circumferences, wherein the lower
ends of the upper tubes are detachably connected to the means by
being inserted into the upper holes, wherein the means bends around
and is welded to the central cylinder, and wherein the seat ends of
the upper tubes are detachably connected to the tube
receptacles.
12. The collapsible chair of claim 11, further comprising: an
elastic cord that passes through one of the upper tubes and into
the means.
13. The collapsible chair of claim 11, wherein the frame further
comprises leg tubes with upper ends, wherein the means is also for
forming lower holes with circular circumferences, and wherein the
upper ends of the leg tubes are detachably connected to the means
by being inserted into the lower holes.
14. The collapsible chair of claim 11, wherein the upper tubes
include two tubes of a first length and two tubes of a second
length, and wherein the first length is longer than the second
length.
15. The collapsible chair of claim 14, wherein each of the two
tubes of the first length is bent, and wherein neither of the two
tubes of the second length is bent.
16. The collapsible chair of claim 14, wherein each of the upper
tubes of the first length has a lower section, a middle section and
an upper section, wherein the lower end of each upper tube of the
first length is disposed on the lower section of the upper tube,
wherein each lower section is bent, and wherein each middle section
and each upper section is not bent.
17. A method comprising: forming upper tubes with lower ends and
seat ends, wherein the upper tubes are formed in sections, and
wherein the lower ends have circular cross setions; forming leg
tubes with upper ends; bending first tubes around a central
cylinder from below and welding the first tubes to the central
cylinder, wherein upper holes with circular circumferences are
disposed at ends of the first tubes, and wherein the circular cross
sections of the lower ends are dimensioned to fit snugly into the
circular circumferences of the upper holes; bending second tubes
around the central cylinder from above and welding the second tubes
to the central cylinder, wherein lower holes with circular
circumferences are disposed at ends of the second tubes, and
wherein the upper ends of the leg tubes are dimensioned to fit
snugly into the lower holes; and making a seat back with tube
receptacles disposed at locations on the seat back so as to fit
over the seat ends of the upper tubes.
18. The method of claim 17, further comprising: pulling an elastic
cord through one of the first tubes and into one of the upper
tubes.
19. The method of claim 17, wherein the central cylinder has a
diameter that is larger than that of the upper tubes.
20. The method of claim 17, further comprising: placing the upper
tubes, the leg tubes, the central cylinder, the first tubes, the
second tubes and the seat back in a bag that is less than one foot
long.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is based on and hereby claims the benefit
under 35 U.S.C. .sctn.119 from Korean Patent Application No.
2020140008443, filed on Nov. 18, 2014, in the Republic of Korea,
the subject matter of which is incorporated herein by reference.
This application is a continuation-in-part of Korean Application
No. 2020140008443. In addition, this application is a
continuation-in-part of, and claims priority under 35 U.S.C.
.sctn.120 from, nonprovisional U.S. patent application Ser. No.
29/507,520 entitled "Collapsible Chair with Poles Extending from a
Central Bar," filed on Oct. 28, 2014, the subject matter of which
is incorporated herein by reference.
TECHNICAL FIELD
[0002] The described embodiments relate to chairs, and more
particularly to portable, collapsible chairs that are suitable for
camping, fishing, outdoor concerts and sporting events.
BACKGROUND
[0003] Portable chairs are convenient during outdoor activities at
which seating is otherwise unavailable. Folding chairs that are
commonly used in the home to save space are not sufficiently
portable for most outdoor activities, such as camping, hiking,
fishing, outdoor concerts and sporting events. A portable chair for
outdoor activities should be light weight and compact. For example,
a chair used for hiking or camping should advantageously fit into a
back pack and not weigh down the hiker. The typical tube-and-canvas
folding chairs used at field-side sporting events are simply too
large and heavy to take along on a hike. A smaller and lighter
folding chair would also be more convenient even at events on a
field that is a short distance from the trunk of the user's
car.
[0004] FIG. 1 (prior art) shows an assembled, light-weight,
collapsible chair 10 that is appropriate for hiking and camping.
Chair 10 is assembled around two molded-plastic tube connectors 11.
The ends of a central bar 12 fit into openings in two plastic bar
connectors 11. In addition, legs and support bars 13 are inserted
into openings in the plastic bar connectors 11 in order to assemble
chair 10. The other ends of the support bars 13 are then inserted
into corner pockets of a canvas seat back 14.
[0005] FIG. 2 (prior art) shows collapsible chair 10 of FIG. 1 in a
disassembled state. The legs and support bars 13 are removed from
the bar connectors 11 and can be folded into the canvas seat back
14. Thus, collapsible chair 10 can be conveniently packed into a
small bag or back pack. However, collapsible chair 10 has the
disadvantage of being unstable, particularly on the uneven ground
typically present at outdoor activities, such as camping, hiking
and fishing. Occupants of chair 10 have a tendency to fall
backwards because the longer back support bars result in the center
of gravity being well behind the central bar 12. In addition, the
plastic of the bar connectors 11 is not strong enough to hold the
support bars 13 in place under the weight of the occupant.
Especially after the occupant has been seated for an extended
period, the plastic bar connectors 11 cannot prevent the back
support bars from bending backwards, which can shift the center of
gravity even behind the ends of the back legs.
[0006] A compact, light-weight collapsible chair is sought that is
nevertheless sturdy, stable and suitable for use on uneven
ground.
SUMMARY
[0007] A sturdy, compact collapsible chair includes upper tubes,
leg tubes, a central tube connector and a fabric seat back. All of
the tubes are hollow and metal. The central tube connector has two
first short tubes bent around a central cylinder from below and two
second short tubes bent around the central cylinder from above. The
central cylinder has a diameter that is larger than the diameter of
the upper tubes, leg tubes and first and second short tubes. The
two first short bent tubes are welded to the bottom of the central
cylinder, and the two second short bent tubes are welded to the top
of the central cylinder. Each pair of first and second bent tubes
is also welded together. Upper holes are formed at the ends of the
first tubes, and lower holes are formed at the ends of the second
tubes. The upper tubes are formed from detachable sections. Each of
the back upper tubes has an upper section, a middle section and a
lower section. Each front upper tube has an upper section and a
lower section.
[0008] The lower end of each upper tube is inserted into one of the
upper holes in the first bent tubes, and the upper end of each of
the leg tubes is inserted into one of the lower holes in the second
bent tubes. Each of the lower ends of the upper tubes has a
circular cross section that is dimensioned to fit snugly into the
circular circumference of a corresponding upper hole. Upper ends of
the upper tubes fit into tube receptacles in the seat back. No part
of the upper tubes other than the upper and lower ends contacts any
part of the collapsible chair. The two back upper tubes are longer
than the two front upper tubes. The lower section of each of the
two back upper tubes is curved, whereas both sections of each front
upper tube are straight.
[0009] A method of manufacturing the sturdy, collapsible chair
includes forming tubes, a central tube connector and a seat back
and then placing the tubes, connector and seat back in a bag that
is less than one foot long. A plurality of upper tubes are formed
in detachable sections. Each back upper tube has an upper section,
a middle section and a lower section. The upper and middle sections
are straight, whereas the lower section is bent. Each front upper
tube has a straight upper section and a straight lower section. The
upper tubes have lower ends and seat ends. A plurality of leg tubes
are formed with upper ends and ground ends. The lower ends of the
upper tubes and the upper ends of the leg tubes have outer
diameters that are dimensioned to fit snugly into the inner
diameters of the regular tube dimensions.
[0010] The central tube connector is formed by bending first short
tubes around a central cylinder from below and welding the first
tubes to the central cylinder. Second tubes are bent around the
central cylinder from above and are welded to the central cylinder.
Upper holes with circular circumferences are disposed at the ends
of the first bent tubes, and lower holes with circular
circumferences are disposed at the ends of the second bent tubes.
The circular cross sections of the lower ends of the upper tubes
are dimensioned to fit snugly into the circular circumferences of
the upper holes of the first bent tubes, and the upper ends of the
leg tubes are dimensioned to fit snugly into the lower holes of the
second bent tubes. An elastic cord is pulled through each of the
tubes. An elastic cord is passes from each front upper tube,
through an upper hole, through a first bent tube, out another upper
hole and into a back upper tube. Similarly, an elastic cord is
passes from each front leg tube, through a lower hole, through a
second bent tube, out another lower hole and into a back leg tube.
The seat back has a plurality of tube receptacles disposed at
locations on the seat back so as to fit over the seat ends of the
upper tubes.
[0011] Other embodiments and advantages are described in the
detailed description below. This summary does not purport to define
the invention. The invention is defined by the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The accompanying drawings, where like numerals indicate like
components, illustrate embodiments of the invention.
[0013] FIG. 1 (prior art) is a perspective view of a collapsible
chair assembled around two plastic bar connectors.
[0014] FIG. 2 (prior art) shows the components of the collapsible
chair of FIG. 1 before they are assembled.
[0015] FIG. 3 is a perspective view of an assembled sturdy,
collapsible chair according to the present invention.
[0016] FIG. 4 is a perspective view of one end of the central tube
connector of the chair of FIG. 3.
[0017] FIG. 5 shows the central tube connector of the chair of FIG.
3 looking down the central axis of the central cylinder.
[0018] FIG. 6 shows the frame of the chair of FIG. 3 in the
collapsed state in the process of being assembled.
[0019] FIG. 7 shows the tubes of the frame of the chair of FIG. 3
bunched up parallel to one another to be placed in a bag.
[0020] FIG. 8 is a perspective view of the chair of FIG. 3 in the
assembled state before the seat back is placed over the upper
tubes.
[0021] FIG. 9 shows an occupant sitting in the assembled
collapsible chair of FIG. 3.
[0022] FIG. 10 is a flowchart of steps of a method of manufacturing
the collapsible chair of FIG. 3.
DETAILED DESCRIPTION
[0023] Reference will now be made in detail to some embodiments of
the invention, examples of which are illustrated in the
accompanying drawings.
[0024] FIG. 3 shows a sturdy, compact, collapsible chair 15 in an
assembled state. Collapsible chair 15 can easily be disassembled
and placed in a small bag that is less than a foot long.
Collapsible chair 15 consists of four upper tubes 16-19, four leg
tubes 20-23, a central tube connector 24, four elastic cords with
associated plugs, and a seat back 25. The upper tubes 16-19 and leg
tubes 20-23 are hollow tubes with circular cross sections. The back
two upper tubes 18-19 are longer than the front two upper tubes
16-17. The front two upper tubes 16-17 have detachable upper and
lower sections, while the back two upper tubes 18-19 have
detachable upper, middle and lower sections. The central tube
connector 24 has a central cylinder 26, two first bent tubes 27-28,
and two second bent tubes 29-30. In one embodiment, the upper tubes
16-19, the leg tubes 20-23, the central cylinder 26, the two first
bent tubes 27-28, and two second bent tubes 29-30 are all made of
aluminum, which is light weight but yet strong. Thus, the
light-weight, compact, collapsible chair 15, which fits into a
small bag, is suitable especially for hiking and camping. In
another embodiment, all of the tubes are made of steel, with is
heavier but stronger than aluminum.
[0025] The leg tubes 20-23, the sections of the upper tubes 16-19,
the first bent tubes 27-28, and second bent tubes 29-30 all have
the same diameter. The diameter of central cylinder 26 is larger
than the diameter of the other tubes. In one embodiment, central
cylinder 26 has an outer diameter of one inch, and the other tubes
have an outer diameter of one half inch. One end of each of the leg
tubes 20-23 and each section of the upper tubes 16-19 has a smaller
outside diameter that fits inside the inner diameter of the regular
tube dimensions. For example, the lower end of the lower section of
the upper tube 17 has a one-inch length with a three-eighths-inch
outer diameter that fits inside the inner diameter of the first
bent tube 28.
[0026] FIG. 4 is a perspective view of one end of the central tube
connector 24 in more detail. The central tube connector 24 is
formed by bending the first and second short tubes 27-30 around the
central cylinder 26. Each of the first short tubes 27-28 is bent
around central cylinder 26 from below to form an open "U". Two
upper holes with circular circumferences are disposed at the ends
of each first tube 27-28. For example, FIG. 4 shows upper hole 31
in first short tube 28. The angle between the arms of the "U" is
slightly less than ninety degrees. Each of the first tubes 27-28 is
welded to the central cylinder 26 at the bottom of the cylinder
such that the ends of each bent first tube slant up and outward by
about thirty degrees from perpendicular to the central axis of the
central cylinder 26. FIG. 4 shows the weld 32 at the bottom of the
central cylinder 26 that attaches the first tube 28 to the central
cylinder. Each of the second short tubes 29-30 is bent around the
central cylinder 26 from above and is welded to the central
cylinder 26 at the top of the cylinder. The second tubes 29-30 are
bent around the central cylinder 26 inside the locations where the
first tubes 27-28 are bent around central cylinder 26. FIG. 4 shows
the weld 33 at the top of central cylinder 26 that attaches the
second tube 30 to the central cylinder. Each of the first tubes 27,
28 is also welded to the corresponding second tube 29, 30 near the
ends of the short tubes. The ends of each bent second tube 29-30
slant down and outward by about thirty degrees from perpendicular
to the central axis of central cylinder 26. Two lower holes with
circular circumferences are disposed at the ends of each second
tube 29-30.
[0027] FIG. 5 shows the central tube connector 24 looking down the
central axis of the central cylinder 26. FIG. 5 shows how the two
first short bent tubes 27-28 are bent around central cylinder 26
from below. Second short bent tube 30 is bent around central
cylinder 26 from above. The two upper holes 31, 34 with circular
circumferences are shown at the ends of the first short bent tube
28. The upper tubes 16-19 have lower ends and seat ends, and the
leg tubes 20-23 have upper ends and bottom ends. FIG. 5 shows the
lower end 35 of the lower section of the upper tube 17 and the
lower end 36 of the lower section of the upper tube 18. To assemble
the collapsible chair 15, the lower ends of the upper tubes 16-19
are detachably connected to the first tubes 27-28 by being inserted
into the upper holes. For example, the lower end 35 of upper tube
17 is inserted into upper hole 31 of first tube 28, and the lower
end 36 of upper tube 18 is inserted into upper hole 34 of first
tube 28. Similarly, to assemble the collapsible chair 15, the upper
ends of the leg tubes 20-23 are detachably connected to the second
tubes 29-30 by being inserted into the lower holes.
[0028] FIG. 6 shows the frame 37 of collapsible chair 15 in the
collapsed state. The frame is made entirely of metal tubes. Thus,
no additional manufacturing equipment or processes are required to
work with materials other than the hollow metal tubing. For
example, no molds are required to make the plastic bar connectors
11 of the collapsible chair 10 of the prior art. The tubes
themselves are used as a means for forming the holes into which the
ends of other tubes are detachably connected to assemble the
collapsible chair 15. FIG. 6 shows that the shorter front two upper
tubes 16-17 have detachable upper and lower sections, while the
back two upper tubes 18-19 have detachable upper, middle and lower
sections. For example, front upper tube 17 has an upper section 38
and a lower section 39, and back upper tube 18 has an upper section
40, a middle section 41 and a lower section 42. The seat ends of
the upper tubes 16-19 are opposite the lower ends 43, 35, 36 and 44
that fit snugly into the upper holes 45, 31, 34 and 46,
respectively. The circular cross section of each of the lower ends
43, 35, 36 and 44 is dimensioned to fit snugly into the circular
circumference of the corresponding upper hole 45, 31, 34 and
46.
[0029] Returning to FIG. 3, the seat ends of the upper tubes 16-19
are shown detachably connected to the tube receptacles 47-50,
respectively, at the four corners of the seat back 25. The seat
back 25 is made of stitched pieces of woven fabric, such as canvas.
The seat back 25 is stretched so that the tube receptacles 47-50
will fit over the seat ends of the upper tubes 16-19. The curved
back upper tubes 18-19 can have only one orientation in the upper
holes and still fit into the tube receptacles 47-50. Thus, in the
assembled state, the upper tubes 16-19 are under some tension that
pulls the seat ends together. In one embodiment, the tube
receptacles 47-50 are pockets sewn in the fabric of the seat back
25. In another embodiment, the tube receptacles 47-50 are hard
plastic cylinders into which the seat ends of the upper tubes 16-19
slide. The plastic cylinders are either glued or stitched to the
fabric of the seat back 25. In the assembled state of collapsible
chair 15, no part of the upper tubes 16-19 other than the lower
ends and the seat ends contacts any part of the collapsible chair.
The bottom ends of the leg tubes 20-23 rest on the ground.
[0030] FIG. 7 shows the upper tubes 16-19, the leg tubes 20-23 and
the central tube connector 24 in the collapsed state bunched up to
be placed in a bag. Because the central cylinder 26 and each of the
other tube sections is less than one foot long, the entire
collapsible chair 15 can fit into a bag that is less than one foot
long. The collapsed tubes of the frame 37 are rolled up in the seat
back 25 before being inserted into the bag. In the collapsed state
of FIG. 7, all of the tubes 16-23 have been pulled out of the holes
in the central tube connector 24. In addition, the sections of the
upper tubes 16-19 have been pulled apart. Elastic cords pass
through all of the upper tubes, leg tubes, first bent tubes and
second bent tubes. When the tubes of the frame 37 are removed from
their bag, the elastic cords tend to pull the tube sections into
one another and the upper tubes and leg tubes into the holes in the
first bent tubes and the second bent tubes. The user can then align
the tube sections with each other and with the upper and lower
holes, and the tubes are pulled into the central tube connector 24.
Thus, the elastic cords tend to pull the tubes of the frame 37 into
the assembled state. Once in the assembled state, the tubes are
held in place by the elastic cords. The ends of the elastic cords
are attached to the inside of plugs that fit into the seat ends of
the upper tubes 16-19 or into the bottom ends of the leg tubes
20-23. An elastic cord passes from an end plug at the seat end of
each front upper tube 16-17, through one of the first bent tubes
27-28 and through a back upper tube 19-18 to an end plug at the
seat end of the back upper tube. In addition, an elastic cord
passes from a ground plug at the bottom end of each front leg tube
20-21, through one of the second bent tubes 29-30 and through a
back leg tube 23-22 to a ground plug at the bottom end of the
corresponding back leg tube. Thus, there are four elastic cords
that each pass through the means 27-30 for forming the upper and
lower holes. For example, portions of an elastic cord 51 can be
seen in FIG. 7 that passes from an end plug 52 at the seat end of
front upper tube 17, through first bent tube 28 and through back
upper tube 18 to an end plug 53 at the seat end of back upper tube
18.
[0031] FIG. 8 is a perspective view of the frame 37 of collapsible
chair 15 in the assembled state before the tube receptacles at the
corners of the seat back 25 have been slipped over the seat ends of
the upper tubes 16-19. FIG. 8 shows that the back upper tubes 18-19
with three sections have a first length that is longer than the
second length of the front upper tubes 16-17, which have only two
sections. The longer back upper tubes 18-19 support the back of the
seat back 25, whereas the shorter front upper tubes 16-17 support
the seat of the seat back 25 upon which the user's legs rest. The
lower sections 42 and 54 of each of the back upper tubes 18 and 19
are curved, whereas the middle and upper sections of the back upper
tubes 18 and 19 are straight. By curving the back upper tubes 18,
19 upwards at the lower sections 42, 54, the seat ends 55, 56 of
the back upper tubes are moved forward closer to the central
cylinder 26, and the center of gravity of the occupant of
collapsible chair 15 is moved in front of the central cylinder 26.
Thus, bending the lower sections 42, 54 allows the center of
gravity to be in front of the central cylinder 26 even through the
back upper tubes 18-19 that support the back of the seat are
significantly longer than the front upper tubes 16-17. The occupant
of collapsible chair 15 does not have a tendency to fall backwards
as is the case with prior art collapsible chair 10, whose back bars
are entirely straight from the plastic bar connectors 11 to the
corner pockets of the seat back 14. In addition, bending the lower
sections 42, 54 moves the back upper tubes 18, 19 away from the
bottom of the seat back 25, which is pressed down by the occupant.
It would be uncomfortable for the occupant to feel the back support
tubes when sinking into the chair if the back support tubes were
entirely straight.
[0032] FIG. 9 shows an occupant 57 sitting in the assembled
collapsible chair 15. FIG. 9 illustrates that the center of gravity
of the occupant 57 is in front of the central cylinder 26 even
though the occupant is resting on the back of the seat. Moreover,
the bent lower sections 42, 54 remain a significant distance away
from the bottom of the seat back 25 that is pressed down by the
occupant 57. Even if the seat back 25 were larger and lower slung
than in FIG. 9, the occupant 57 would still not press against the
back upper tubes 18-19.
[0033] The second bent tubes 29-30 are metal welded to the metal
central cylinder 26 and are therefore stronger than the plastic bar
connectors 11 of the prior art chair 10. In addition, the strength
of a plastic bar connector 11 is often insufficient to maintain the
angle between each pair of front and back leg bars, and the leg
bars warp to a more open angle than the plastic bar connector 11
can hold. Each of the second bent tubes 29, 30 of sturdy chair 15
is strong enough to hold its pair of leg tubes 20, 23 and 21, 22,
respectively, under the weight of the occupant 57 at an angle that
slants down and outward by about thirty degrees from perpendicular
to the central axis of central cylinder 26. Thus, the bottom ends
of the leg tubes 20-23 are spaced farther apart and provide a wider
and more stable base than the leg bars of prior art chair 10, which
do not slant to the sides as is evident in FIG. 1.
[0034] FIG. 10 is a flowchart illustrating steps 60-66 of a method
of manufacturing collapsible chair 15. In a first step 60, the
detachable sections of the upper tubes 16-19 are formed from hollow
metal tubes with circular cross sections. The metal can be aluminum
or steel. Each of the sections of the upper tubes 16-19 has a lower
end with a smaller outer diameter. The lower end of each tube
section is dimensioned to fit snugly into the hole formed by the
end of the tube below. For example, the lower end of the upper
section 40 of tube 18 is dimensioned to fit snugly into the hole at
the top of the middle section 41. Similarly, the lower end of the
middle section 41 of tube 18 is dimensioned to fit snugly into the
hole at the top of the lower section 42. The lower end of lower
section 42 is the lower end of upper tube 18.
[0035] In step 61, the leg tubes 20-23 are also formed from hollow
metal tubes with the same diameter as the upper tubes 16-19. Each
leg tube has only a single section. The leg tubes 20-23 have upper
ends and lower ground ends. At the upper ends of the leg tubes
20-23 there is an upper portion that has a smaller outer diameter
than the rest of the leg tubes.
[0036] In step 62, the first short bent tubes 27-28 are bent around
the central cylinder 26 from below and are welded to the central
cylinder 26 at the bottom of the cylinder. The upper holes 45-46
have circular circumferences and are disposed at the ends of the
first tube 27, and the upper holes 31, 34 have circular
circumferences and are disposed at the ends of the first tube 28.
The circular cross sections of the lower ends of the upper tubes
16-19 are dimensioned to fit snugly into the circular
circumferences of the upper holes 31, 34, 43, 46.
[0037] In step 63, the second short bent tubes 29-30 are bent
around the central cylinder 26 from above and are welded to the
central cylinder 26 at the top of the cylinder. Lower holes with
circular circumferences are disposed at the ends of the second
tubes 29-30. The circular cross sections of the upper ends of the
leg tubes 20-23 are dimensioned to fit snugly into the circular
circumferences of the lower holes.
[0038] In step 64, the seat back 25 is made with the four tube
receptacles 47-50 disposed at the corners of the approximately
rectangular seat back so as to fit over the seat ends of the upper
tubes 16-19. The seat back 25 is made by stitching together various
pieces of fabric or plastic. The tube receptacles 47-50 can be sewn
as pockets into the seat back or they can be molded plastic
cylinders that are glued or stitched to the corners of the seat
back 25.
[0039] In step 65, an elastic cord is pulled through each pair of
front and back upper tubes and each pair of front and back leg
tubes. The two elastic cords that pass through the front and back
upper tubes also pass through the first short bent tubes 27-28. The
two elastic cords that pass through each pair of leg tubes also
pass through the second short bent tubes 29-30. For example, an
elastic cord 51 that attaches to an end plug 53 at the seat end 55
of upper tube 18 is pulled through the sections of back upper tube
18, into upper hole 34, through first short bent tube 28, out upper
hole 31, through the sections of front upper tube 17 and attaches
to an end plug 52 at the seat end of tube 17. Similarly, another
elastic cord that attaches to a ground plug of leg tube 22 is
pulled through tube 22, into a lower hole, through second short
bent tube 30, out another lower hole, through leg tube 21 and
attaches to a ground plug at the bottom end of front leg tube
21.
[0040] In step 66, all of the tube sections are detached from one
another and the tubes are detached from central tube connector 24.
The tubes are then oriented relatively parallel to one another, as
shown in FIG. 7. The tubes are then rolled up in the seat back 25,
and the upper tubes 16-19, the leg tubes 20-23, the central
cylinder 26, the first short bent tubes 27-28, the second short
bent tubes 29-30 and the seat back 25 are placed in a bag. Because
each of the central cylinder 26, the tube sections and the leg
tubes is less than twelve inches long, the components of
collapsible chair 15 fit in a bag that is less than a foot long,
which is ideal for camping and hiking. The bag is less than six
inches in diameter.
[0041] To assemble the collapsible chair 15, the user removes the
tubes and the seat back 25 from the bag and unwraps the seat back
from around the tubes. The user then aligns the tube sections with
each other and with the upper and lower holes. The elastic cords
tend to pull the tube sections into one another and the upper tubes
into the upper holes in the first bent tubes. The elastic cords
also pull the leg tubes into the lower holes in the second bent
tubes. The back upper tubes 18-19 are formed when the upper
sections are detachably connected to the middle sections, and the
middle sections are detachably connected to the lower sections. The
front upper tubes 16-17 are formed when the upper sections are
detachably connected to the lower sections. To assemble the
collapsible chair 15, the lower ends of the upper tubes 16-19 are
detachably connected to the first tubes 27-28 by being inserted
into the upper holes 45, 46, 34, 31, and the upper ends of the leg
tubes 20-23 are detachably connected to the second tubes 29-30 by
being inserted into the lower holes.
[0042] Although certain specific exemplary embodiments are
described above in order to illustrate the invention, the invention
is not limited to the specific embodiments. Accordingly, various
modifications, adaptations, and combinations of various features of
the described embodiments can be practiced without departing from
the scope of the invention as set forth in the claims.
* * * * *