U.S. patent number 3,768,863 [Application Number 05/153,260] was granted by the patent office on 1973-10-30 for chair construction.
This patent grant is currently assigned to Royal Seating Corporation. Invention is credited to Roy E. Jennings.
United States Patent |
3,768,863 |
Jennings |
October 30, 1973 |
CHAIR CONSTRUCTION
Abstract
The chair includes a base structure and a seat structure secured
to the base. The base structure has pairs of downwardly extending
legs connected by a horizontal portion. The horizontal portions are
secured to each other by spaced apart pairs of angle bracket
assemblies, with each angle of a pair separated from the other to
facilitate assembly. The seat structure includes an integrally
molded seat-back shell mounted on a tubular frame having brackets
which slip over and are secured to one of the angles of each of the
angle bracket assemblies. The seat structure is held to the base
structure by machine screws so that the chair assembly can be
shipped in a knocked-down condition and readily assembled after
shipment. A tablet arm or desk arm can be secured to the chair if
required. While the back-seat-shell is molded from an essentially
rigid plastic material, the construction is such that the back can
deflect slightly relative to the seat to enhance comfort. The
comfort of the shell is further enhanced by the upwardly curved
seat, the buttocks relief opening in the back of the shell, and the
shallow V-shaped spine relief along the back of the shell.
Inventors: |
Jennings; Roy E. (Temple,
TX) |
Assignee: |
Royal Seating Corporation
(Cameron, TX)
|
Family
ID: |
25172175 |
Appl.
No.: |
05/153,260 |
Filed: |
June 15, 1971 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
797949 |
Feb 10, 1969 |
3628832 |
|
|
|
Current U.S.
Class: |
297/451.1;
297/160 |
Current CPC
Class: |
A47C
3/12 (20130101); A47C 7/68 (20130101); A47C
5/04 (20130101) |
Current International
Class: |
A47C
5/00 (20060101); A47C 3/00 (20060101); A47C
7/68 (20060101); A47C 7/62 (20060101); A47C
5/04 (20060101); A47C 3/12 (20060101); A47c
001/12 (); A47c 005/00 () |
Field of
Search: |
;297/451,445,452,454,457,458,460,284,239 ;5/327,327B,338
;248/188 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Gilliam; Paul R.
Parent Case Text
This is a division of application of Ser. No. 797,949 filed Feb.
10, 1969, now U.S. Pat. No. 3,628,832.
Claims
What is claimed is:
1. An integral seat-back shell formed from rigid material, said
shell having a front surface and a rear surface and comprising, in
combination;
a substantially horizontal seat having a shallow dish-shaped upper
surface, forming part of the front surface of the shell, and having
smooth sides;
a substantially upright back integral with and extending upwardly
from said seat, said back having front faces forming part of the
front surface of the shell;
said front faces of said back including substantially flat surfaces
originating adjacent sides of the back, extending toward each
other, and merging to form a shallow V-shaped spine relief
extending along the vertical centerline of the back, the angle
between said flat front faces at the spine relief increasing in a
direction from said buttocks relief area toward the top of the
back; and
means defining a rearwardly extending buttocks reliev area at the
base of the back, said area having a width at least as great as its
height and being generally symmetrical about said vertical
centerline;
said buttocks relief area allowing the buttocks of the occupant to
distend rearwardly, and said V-shaped spine relief enhancing the
comfort of the chair for an occupant with a protruding
backbone.
2. A seat-back shell according to claim 1 wherein
the angle between said flat front faces varies from approximately
160.degree., adjacent the top of said opening to approximately
145.degree. adjacent the top of the back portion.
3. A seat-back shell according to claim 1 wherein
a continuous first wall extends along said seat and back adjacent
one side thereof and projects away from the front surface of the
shell;
a continuous second wall extends along said seat and back adjacent
the other side thereof and projects away from the front surface of
the shell; and
the front of said seat curves downwardly and merges with the front
ends of each of said walls.
4. A seat-back shell according to claim 3 wherein
a continuous top wall, adjacent the top of the back, extends
between and joins the upper ends of said first and second
walls;
whereby, said first and second walls, top wall, and curved front
form a continuous strengthening frame extending around the
shell.
5. A seat-back shell according to claim 3 wherein
said continuous first wall extends along one side of the shell and
is planar along a substantial portion of its length;
said continuous second wall extends along the other side of the
shell and is planar along a substantial portion of its length;
and
the width of said walls is greatest at the region adjacent the
junction of the seat with the back.
6. A seat-back shell according to claim 5 wherein said first and
second walls converge from the front of the seat to the top of the
back.
7. A seat-back shell according to claim 4 wherein
a first continuous strengthening rib extends along the rear surface
of the shell from a location near the front of the seat to a
location near the top of the back, said first rib extending
generally parallel with said first wall and on the same side of the
buttocks relief area as said first wall; and
a second continuous strengthening rib extends along the rear
surface of the shell from adjacent the front of the seat to
adjacent the top of the back, said second rib extending generally
parallel with said second wall and on the same side of said
buttocks relief area as said second wall.
8. A seat-back shell according to claim 7, wherein
a transverse rib extends between and merges with the strengthening
ribs at a location spaced from the front of the seat.
9. A seat-back shell according to claim 8 wherein
said walls and continuous strengthening ribs cooperate with said
opening to provide for limited flexing of said back relative to
said seat about the junction of the back and seat.
10. A seat-back shell according to claim 1 wherein
said buttocks relief area is an opening with the shape of an
isosceles triangle with a base of a length greater than its height;
and
the apex of the isosceles triangle shaped opening is at the
vertical centerline of the back.
11. A seat-back shell according to claim 1 wherein the buttocks
relief area includes an opening extending through the back;
the width of the opening is at least one-half the width of the back
as measured at the juncture of the seat and back; and
the opening cooperates with the seat and back to permit slight
flexing of the back relative to the seat to enhance the comfort of
the seat-back shell.
12. A seat-back construction for a chair comprising
a seat-back shell having a seat and an upright back integral with
the seat, and being generally symmetrical about a vertical central
plane;
a first continuous longitudinally extending rib integral with the
shell and offset to one side of the central plane and extending
from a location near the front of the seat to a location near the
top of the back, along the rear of the shell, said first rib having
an inside surface facing toward the central plane;
a second continuous longitudinally extending rib integral with the
shell and offset to the other side of the central plane and
extending from a location near the front of the seat to a location
near the top of the back, along the rear of the shell, said second
rib having an inside surface facing toward the central plane;
first transverse rib means joining each of said longitudinal ribs
beneath the seat, and extending inwardly toward the central
plane;
second transverse rib means joining each of said longitudinal ribs
at the rear of the back and extending inwardly toward the central
plane;
first elongated continuous support means extending in closely
adjacent relation to the rear of the shell and along the inside
surface of said first longitudinal rib from said first transverse
rib means to said second transverse rib means, said first support
means having a front portion adjacent said first transverse rib
means and an upper portion adjacent said second transverse rib
means;
second elongated continuous support means extending in closely
adjacent relation to the rear of the shell and along the inside
surface of said second longitudinal rib from said first transverse
rib means to said second transverse rib means, said second support
means having a front portion adjacent said first transverse rib
means and an upper portion adjacent said second transverse rib
means;
connecting means securing said front portions of said support means
to said shell; and
connecting means securing said upper portions of said support means
to said shell.
13. A construction according to claim 12 wherein
said front portions of said elongated support means are flattened
respectively, in planes parallel with the respective inside
surfaces;
said rear portions of said elongated support means are flattened
respectively, in planes parallel with the respective inside
surfaces; and
said connecting means are fasteners extending through the flattened
portions and securing the support means to the longitudinal ribs
along which they extend.
14. A construction according to claim 12 wherein
said front portions are front ends of the elongated support means
and are each flattened to lie against the respective inside
surfaces along which they extend;
said upper portions are each ends of the elongated support means
and are each flattened to lie against the respective inside
surfaces of the longitudinal ribs along which they extend;
said first transverse rib means have inside surfaces extending over
the tips of said front ends; and
said second transverse rib means have inside surfaces extending
over the tips of said rear ends.
15. A construction according to claim 14 wherein said support means
are each
elongated tubular elements.
16. A construction according to claim 14 wherein
connector brackets are secured respectively to said tubular
elements and project downwardly from said elements in aligned
relation to each other transversely of said seat.
Description
This invention relates generally to chair assemblies and
particularly to chair assemblies for schoolroom use.
Schoolroom or educational furniture is uniquely different from
other types of household and business furniture. Schoolroom
furniture must necessarily be quite rugged to withstand the rough
treatment of the furniture by school age children. The furniture
must be available in sizes for the various age groups of the school
children. Another important requirement of school furniture is that
it must be easy to clean and not contain materials to support
bacterial or insect growth. In addition, school furniture should be
comfortable. Otherwise, the student's attention may be diverted
from the classroom activities to the uncomfortable chair in which
he sits. While the comfort factor has been considered by school
authorities in the past, usually, cost considerations are more
significant than the matter of comfort. As a result, school
authorities have not deemed comfort to be a primary consideration
in the purchase of classroom furniture, but have instead looked for
low cost and durability.
From the standpoint of the manufacturer, the desirable features of
classroom furniture are durability, economy of manufacture, economy
of shipment, appearance, and comfort. Since a handsome chair
enhances the atmosphere of the classroom, certainly, appearance is
a primary consideration to the manufacturer in the sale of the
product. With regard to economy of manufacture, simplicity is
indeed a primary consideration of the manufacturer since the less
complex the chair or other furniture is, the less expensive it will
be to manufacture. Related to simplicity is the cost of tooling to
make the chair or other item of furniture on a mass production
competitive basis.
Not to be overlooked by the manufacturer is the comfort of the
chair. Comfort in a chair, while not considered important in the
past, is becoming increasingly significant in the salability of
chairs and other school furniture. The increase of the significance
of comfort is believed to be based on the recent realization that
attention and grades are better and disciplinary problems are fewer
where the student is comfortable in the chair in which he sits for
perhaps 6 hours each school day. Hence, the educational rating of
the institution which uses comfortable furniture correspondingly
increases.
With regard to economy of shipping, it is desirable that the chair
or other furniture be so constructed that it can be shipped in a
knocked-down condition, and that it can be quickly and easily
assembled with simple hand tools after shipment. Applicant has
found that with the chair of this invention, where the seat-back
structure can be readily removed from the base structure, and where
both the seat and base are nestable with like seats and bases, both
the volume of the shipping space required, as well as the amount of
carton material for packing the chairs is substantially
decreased.
Another consideration from the standpoint of the manufacturer is
the ease with which various accessories, such as tablet arms or
desk arms can be added to the basic chair. It is indeed desirable
to be able to add, for example, a tablet arm to a basic chair so
the chair may be sold with or without the tablet arm. In addition,
a tablet arm which is readily installed after shipment is
advantageous because of lower shipping costs.
With the chair of this invention, applicant satisfies the
requirements of both the school authorities and the manufacturer by
providing a unique chair construction for schoolroom and other
educational purpose use. As will subsequently be described in
detail with reference to a preferred embodiment of the chair of
this invention, the chair embodies a base structure comprised of
downwardly extending pairs of tubular legs connected by an integral
generally horizontal portion. The horizontal portion of each pair
of legs is secured to angle brackets which extend between the
horizontal portions. Each angle bracket is comprised of two
unattached separate angle members which engage and are fixed to the
horizontal portions of the leg pairs. The angle brackets are so
arranged that the seat structure, to which tubular support members
are connected, can be secured to the base structure by slightly
spreading connecting brackets fixed to the tubular members and then
securing same directly to the angle brackets with bolts. This
arrangement provides for shipping the chair structure in a
knocked-down condition with the seat removed from the base so that
several seat units and several base units can be nested for
shipping, or the seat structure can be inverted over the base
structure to provide a low profile package.
The seat-back shell is of unique molded construction and includes
strengthening ribs as well as connector ribs by which the tubular
seat support elements are secured to the seat shell. The
arrangement of the reinforcing ribs coupled with the tubular
support members provides a seat with some "give" which permits the
back of the seat to flex somewhat relative to the base of the seat
about the junction of the seat and base. This "give" or flexture
provides for a springiness which enhances the comfort of the chair
to students of various builds and sizes. An additional significant
feature of the seat-back shell is a buttocks relief opening which
provides room for some expansion of the buttocks through the
opening when a student sits erect with the base of his spine at the
rear of the seat. The buttocks relief opening cooperates with the
generally shallow V-shaped configuration of the seat back to
provide a structure with enhanced comfort over that of the prior
art molded seat shells. For students of a build termed as "skinny",
with a protruding spine, the shallow V-shaped configuration of the
chair back provides a space for spine relief along the vertical
center of the chair back. Thus, the spine of even a very lanky or
skinny student will not directly engage the stiff material of the
chair back. A husky or stocky student will also attain comfort from
the chair because the portions of the chair back which flank the
apex of the "V" will than be engaged by the flesh or muscle of the
stocky student with the result that he too is comfortable in the
chair of this invention. Comfort in the chair is further enhanced
by the dished configuration of the chair seat which curves upwardly
to conform to the configuration of the flanks of the student seated
in the chair.
The connector ribs, molded integral with the seat-back shell,
permit securing the shell to its supports with fasteners which do
not extend through either the seat or back of the shell. Hence,
there are no exposed rivet or screw heads on the seat or back
portions of the shell.
Correspondingly, an object of this invention is a unique chair
structure primarily intended for, but certainly not limited to
educational or classroom use.
Another object is a chair structure in which a seat structure
assembly is readily connectable to a base structure either before
or after shipment of the chair to the place of use.
Another object is a unique base structure for a chair which
includes pairs of opposed parallel angle brackets which cooperate
to secure the horizontal or transverse portions of pairs of legs
together to form the base structure.
Another object related to the immediately preceding object is a
chair structure in which the connecting brackets at each side of
the chair are completely separated from each other and are held
together by the transverse portions of the chair leg pairs.
Another object is a chair structure including a seat-back shell so
constructed that the back is somewhat resilient to give rearwardly
in response to pressure applied by the back of a student seated in
the chair.
A further object is a seat-back shell of integral molded
construction having a back with an inside surface of generally
V-shape which provides a spine relief for the student seated in the
chair.
A further object is an integrally molded seat-back shell in which a
shallow V-shaped inside surface of the back cooperates with a
generally triangular buttocks relief opening to enhance the comfort
of the chair.
A further object is a seat-back shell wherein the seat portion of
the molded shell curves upwardly from a region of greatest
depression toward the back, from a downwardly rolled front edge,
and cooperates with an integral back having a triangular buttocks
relief opening and a shallow V-shaped spine relief at the center
line of the back, with the apex angle of the "V" increasing in a
direction from the top to the bottom of the seat back.
A still further object is a seat shell having integrally formed
connecting ribs to facilitate attachment of the tubular seat-back
support elements by passing fasteners through the ribs and the
elements at locations other than any exposed portions of the seat
or back of the shell.
A still further object is a chair of the type described which may
readily be termed a "basic chair" and which is readily converted to
a tablet arm or desk arm chair merely by connecting the necessary
arms to the base structure, and in which the seat shell assembly is
so constructed that the basic shell, support elements and brackets
permit use of this shell assembly with other educational furniture
constructions.
Numerous other objects, features, and advantages of this invention
will become apparent with reference to the accompanying drawings
which form a part of this specification and in which:
FIG. 1 is a front elevational view of the chair structure of this
invention;
FIG. 2 is a side elevational view of the chair structure;
FIG. 3 is a rear elevational view of the chair structure;
FIG. 4 is a partial side elevational view in section taken along
line 4--4 of FIG. 3;
FIG. 5 is an enlarged view in section taken along line 5--5 of FIG.
4;
FIG. 6 is a plan view of one of the leg connector elements;
FIG. 7 is a front elevational view of the element of FIG. 6;
FIG. 8 is a pictorial view of a seat connector bracket;
FIG. 9 is an enlarged view in section taken along line 9--9 of FIG.
4;
FIG. 10 is a pictorial view showing the manner in which the several
parts of the chair are assembled;
FIG. 11 is an enlarged view in section taken along line 11--11 of
FIG. 10;
FIG. 12 is an enlarged view in section taken along line 12--12 of
FIG. 10, with portions thereof cut away for purposes of
illustration;
FIG. 13 is a vertical sectional view of the seat-back shell taken
along line 13--13 of FIG. 10;
FIG. 14 is a horizontal sectional view taken along line 14--14 of
FIG. 13;
FIG. 15 is a horizontal sectional view taken along line 15--15 of
FIG. 13;
FIG. 16 is a horizontal sectional view taken along line 16--16 of
FIG. 13;
FIG. 17 is a partial front elevational view of the basic chair with
a desk arm attached;
FIG. 18 is a partial side elevational view of the basic chair and
desk arm of FIG. 13;
FIG. 19 is a pictorial view of one desk arm support bracket;
and
FIG. 20 is a pictorial view of the other desk arm support
bracket.
Referring now to the drawings in detail and particularly to FIGS.
1-4 and 10, there is shown a chair 1 which includes a base
structure 2 and a seat structure 3 secured to the base
structure.
Base structure 2 includes a first inverted U-shaped leg unit 4 and
a second inverted U-shaped leg unit 5. Front leg unit 4 has a
transverse or horizontal tubular portion 6, integrally joined to
legs 7 and 8 extending downwardly from smoothly curved bends at the
respective ends of transverse portion 6. Rear leg unit 5 is
identical to front leg unit 6 and includes a tubular transverse or
horizontal portion 9 parallel with portion 6 and integrally joined
to downwardly projecting tapered legs 10 and 11 along smoothly
curved bends at the respective ends of the transverse portion 9.
The lower portions of the legs taper inwardly. Secured to the lower
end of each leg is a glide assembly including a glide 12 mounted at
the end of the leg to swivel so the bottom surface of the glide
rests flat against the floor or surface on which the chair is
placed.
Base structure 2 also includes a left-hand connector set 15 (as
viewed from the rear of the chair) and a right-hand connector set
16, the connector sets extending between the parallel transverse
portions 6 and 9 of the leg units, and securing the leg units
together. As shown at FIGS. 2 and 3, connector sets 15 and 16 are
spaced apart from each other transversely of the chair, with left
connector set 15 offset toward the left side of the chair and right
connector set 16 offset toward the right side of the chair. The
connector sets are welded directly to the tubular transverse
portions 6 and 9 of the respective leg sets and maintain the legs
of the respective leg sets in the inclined relationship shown at
FIG. 2.
Seat structure 3 includes an integrally molded seat-back shell 18
and tubular support elements 19 and 20 secured to shell 18. The
molded shell 18 has a horizontal seat 21 molded integral with an
upright back 22. As shown at FIGS. 3 and 4, tubular support
elements 19 and 20 are L-shaped and each extends from a location
adjacent the front of seat 21 of the shell to a location slightly
more than midway above the back of the shell, and generally follows
the curvature of the under-surface or rear surface 22' of the
shell. Secured to the generally horizontal portions of support
elements 19 and 20, beneath seat 21, are connector brackets 23 and
24 which are adapted to be removably secured to the respective
connector sets 15 and 16 to secure the seat structure 3 to base
structure 2.
Back 22 is of generally trapezoidal shape having side walls 25 and
26 which converge in a direction away from seat 21, and having a
continuous top wall 27 of shallow inverted V-shaped configuration
with wall portions 28 and 29 which meet at an apex 30 along the
vertical center line 31 of shell 18.
At the base of seat portion 22 is opening 32 of isosceles triangle
shape, having a lower generally horizontal upwardly bowed edge 33
and upper side edges 34 and 35 of the same length and which extend
upwardly from each end of the lower edge at an angle of
approximately 30.degree.. Edges 34 and 35 meet at a rounded apex 36
that lies along vertical center line 31, the junctions between
horizontal edge 33 and edges 34 and 35 respectively are smoothly
rounded. With reference to FIGS. 3 and 10, it will be observed that
the maximum horizontal width of opening 32 is slightly greater than
one-half the width of the back, as measured along horizontal edge
33, and is approximately twice the height of triangular opening 32.
Edge 33 is slightly curved and is parallel with, yet spaced
slightly above the correspondingly curved upper surface 37 of seat
21 of the shell.
Seat 21 of shell 18 joins back 22 at the smoothly curved juncture
40 so the front surface 41 of the back extends upwardly at a slight
rearward incline to seat 21. Seat 21 has side walls 42 and 43
respectively, and a rounded front portion 44 which terminates at a
downwardly facing front 45. As shown at FIGS. 1 and 10, side wall
43 of seat 21 is coplaner with side wall 26 of back 22, and the two
side walls merge smoothly at juncture 40 to provide a smooth
continuous side wall 47 extending from the front 44 of the seat to
adjacent top edge 27 of the back. Likewise, side wall 42 is
coplaner with side wall 25 and the two side walls merge smoothly at
juncture 40 and cooperate to provide a continuous side wall 46 of
shell 18 which extends from front 44 of the seat to the top of back
22. It will be observed with reference to FIGS. 1-4 and 10, that
the front portion 44 of the seat is slightly wider than the rear of
the seat adjacent juncture 40 and that the sides of the back
converge in a direction toward the top edge 27 of the back. Hence,
it is apparent that side walls 46 and 47 diverge essentially
uniformly from the top edge 27 of the back to front portion 44 of
the seat. Front 45 curves downwardly and inwardly, and has curved
sides that blend into the front ends of side walls 46 and 47.
It will be observed with reference to FIGS. 1-3 and 10, that the
respective side walls 46 and 47 of the shell extend rearwardly away
from front surface 49 (which includes front surface 41 of the back
and upper surface 37 of the seat) of the shell, and that the
portion 48 of each side wall adjacent juncture 40 has a height or
width which is greater than the height or thickness of these side
walls along the seat and along the back. This portion 48 of greater
width provides additional strength for the shell-18, at the
juncture 40 between the seat 21 and back 22, which is weakened
somewhat by the material of the shell eliminated at opening 32. As
will subsequently be explained, there is additional reinforcing at
the juncture 40 between the seat and the back, so the shell is
quite rugged and durable, yet, this strengthening is such that the
back can flex somewhat relative to the seat and thereby improve the
comfort of the seat for the student sitting on the chair.
It will also be noticed with reference to FIGS. 1-3 and 10, that
top walls 28 and 29 cooperate with side walls 45 and 46 and that
the sidewalls cooperate with the downwardly rounded front 45 to
form a continuous peripheral skirt or frame which projects away
from and borders front surface 22' of the shell.
At a position spaced rearwardly of front 45 of shell 18 is a
transverse bottom rib 50 molded integral with the shell and which
extends downwardly and rearwardly at an acute angle with the
under-surface of seat 21. Bottom rib 50 has a length which is
somewhat less than the distance between sides 42 and 43 of seat 21.
One end of bottom rib 50 is integrally joined to the front end of a
longitudinally extending rib 51 that originates at the end of rib
50 and extends rearwardly and then upwardly along the rear surface
of back 22 and terminates at a location spaced slightly from top
edge 27 of the back. Similarly, the other end of bottom rib 50 is
joined integrally with the front end of a second longitudinally
extending rib 52 which extends rearwardly and then upwardly and
terminates at the same horizontal plane as the upper end of rib 51.
Ribs 51 and 52 are offset respectively toward opposite sides of the
shell, are each continuous along their length, and are parallel
respectively with side walls 46 and 47 of the shell.
At the back of seat 22 are gusset-shaped strengthening ribs 53 and
54 which are integrally joined to ribs 51 and 52. As shown at FIGS.
3 and 4, gusset ribs 53 and 54 incline downwardly to form
downwardly facing pockets 55 and 56, respectively, at opposite
sides of the back. Gusset ribs 53 and 54 each extend inwardly from
ribs 51 and 52, respectively, toward the center of the back and
merge with the material of the back at their inner ends. Front rib
50, longitudinal ribs 51 and 52, and gusset ribs 53 and 54
cooperate to provide a second strengthening frame spaced inwardly
of the periphery or border of shell 18, the outline of this second
strengthening frame being generally parallel with the outline of
the shell and spaced inwardly thereof.
Support elements 19 and 20 are each formed from weldable metal
tubing. As shown at FIG. 4, support element 20 has a single bend 60
formed therein and conforms with the curvature of the rear surface
22' of shell 18. The axis of the tube from which support element 20
is formed lies in a generally horizontal plane. Support element 20
has an upper end 61 which is flattened and severed at an angle to
conform with the configuration of pocket 56. Similarly, front end
62 of support element 20 is flattened and severed at an angle so
front edge 63 lies flat against the inner surface of bottom rib 50.
Ends 61 and 62 are so flattened that the outside surfaces 64 and
65, respectively of the ends lie in a common plane tangent to the
outside of the tube from which support element 20 is formed. Hence,
when support element 20 is secured to shell 18, surfaces 64 and 65
lie flat against the inner surface of rib 52 (FIGS. 4, 5 and 12)
and the side of the tube from which support element 20 is formed in
tangent to the inside surface 65' of the rib.
Support element 19 is the mirror image of support element 20 and
has a flattened upper end 66 and a flattened front end 67. Ends 66
and 67, however, are flattened so they are tangent with the outside
of the tube from which support element 19 is formed. Hence, ends 66
and 67 lie flat against the inside surface 67' of rib 51 when
support element 19 is secured to the seat shell, and the outside of
the tube is tangent to inside surface 67' along the length of the
rib (FIGS. 3, 5 and 12).
Support element 19 is positioned against the inside surface 65' of
rib 51 so end 66 extends into pocket 55 and end 67 is closely
adjacent the inside surface of bottom rib 50. Upper end 66 is
secured to rib 51 with a rivet 71 that extends through aligned
openings in end 66 and rib 51. The front end 67 is similarly
secured with a rivet 72 which extends through aligned openings in
end 67 and rib 51 adjacent bottom rib 50. As shown in FIGS. 3 and
12, the portion of longitudinal rib 51 through which rivet 71
extends is slightly thickened to provide a reinforced section or
tab 73 of added strength. It will be observed with reference to
FIGS. 3--5, that the end edge of upper end 66 is enclosed in pocket
55, and that the end edge of front end 67 is closely adjacent the
inside surface of bottom rib 50, and hence, there are no exposed
sharp edges at the ends of the support element.
Similarly, support element 20 is mounted so it extends along rear
surface 22' of the shell with upper end 61 in pocket 56 and front
end 62 closely adjacent the inside surface of bottom rib 50. One
side of support element 20 engages inside surface 65' of rib 52
along its entire length. The respective ends of support element 20
are secured to rib 52 with rivets 74 and 75, respectively, which
extend through openings in the respective ends and the rib. Rib 52
is thickened at rivet 74 to provide a strengthening tab 76.
Leg units 4 and 5 are secured together with connector sets 15 and
16, respectively. Connector set 15 includes a lower connector
element 80 and an upper connector element 81. Likewise, connector
set 16 includes a lower connector element 82 and an upper connector
element 83. Since connector elements 80-83 are identical, only
connector 80 will be described in detail. As shown in FIGS. 5-7,
connector element 80 is generally L-shaped, is formed from a single
piece of heavy gauge weldable sheet metal, and has a horizontal
wall 84 and a vertical wall 85 projecting perpendicularly from one
side of the horizontal wall. Horizontal wall 84 is longer than
vertical wall 85 and has generally flat projecting ends 86 and 87.
End 86 extends beyond end edge 88 of the vertical wall and end 87
extends beyond end edge 89 of the vertical wall. End edges 88 and
89 have arcuately curved portions 90 and 91 which conform with the
curvature of the respective horizontal portions 6 and 9 of the leg
units. Near end edge 88 in vertical wall 85 is an opening 92, and
near end edge 89 is an opening 93. Each of the openings is stamped
in vertical wall 85 in such a manner that the material of the wall
is extruded inwardly of the angle to form the respective sleeves 94
and 95. The openings 92 and 93 are threaded internally along the
length of the sleeves.
A pair of spaced-apart strengthening gussets 96 and 97 are formed
in horizontal wall 84 and vertical wall 85. These strengthening
gussets are deformed inwardly from the respective outer surfaces 98
and 99 of the vertical wall and horizontal wall respectively.
Gussets 96 and 97 are each continuous from vertical wall 85 to
horizontal wall 84 and extend around the corner between the walls.
The gussets provide a strengthening function which reduces flexture
of horizontal wall 84 relative to vertical wall 85.
An elongated longitudinally extending inwardly deformed
strengthening rib 100 is formed in horizontal wall 84. The rib 100
extends along a substantial portion of the length of wall 84 and
terminates short of the projecting ends 86 and 87. Openings 101 and
102 are formed respectively at the opposite ends of rib 100.
Openings 101 and 102 are locator openings dimensioned to receive
suitable locating pins of a welding jig to facilitate positioning
the connector element against the horizontal portions of the leg
units for welding.
Formed in end 86 of horizontal wall 84 are a pair of longitudinally
extending transversely spaced welding projections 103 and 104 which
project away from surface 98. Similar projections 105 and 106 are
formed in end 87 of wall 84. Projections 103-106 are provided to
facilitate welding connector element 80 to horizontal portions 6
and 9 of the respective leg units by resistance welding.
As shown at FIG. 5, connector element 81 has a horizontal wall 110
and a vertical wall 111, connector element 82 has a horizontal wall
112 and a vertical wall 113, and connector element 83 has a
horizontal wall 114 and a vertical wall 115. As shown at FIGS. 5
and 10, connector element 80 is positioned with the ends of its
horizontal wall 84 extending beneath the horizontal portions 6 and
9 of the leg sets and with vertical wall extending upwardly, and
connector element 81 is positioned so the ends of its horizontal
wall 110 extend above horizontal portions 6 and 9 of the respective
leg sets, and its vertical wall 111 extends downwardly. The
respective ends of horizontal wall 110 are welded to the upper
surface of horizontal portions 6 and 9 respectively, and the
respective ends of horizontal wall 84 are welded to the lower
surface of the respective horizontal portions 6 and 9. Similarly,
connector elements 82 and 83 of connector set 16 are welded to the
horizontal portions 6 and 9 at the opposite side of the base
structure. As shown at FIG. 9, the welding projections 103 and 104
of connector elements 82 and 83 are deformed into tubular
horizontal portion 9 during the welding operation. The connection
between the horizontal portions 6 and 9 with the remaining
connector element ends is the same.
As shown at FIG. 5, connector elements 80 and 81, when secured
between horizontal portions 6 and 9, cooperate to form a generally
box-shaped structure with open diagonally opposite corners 115' and
116. In this regard, it will be noted that connector element 81 is
offset slightly to the right of connector element 80 and hence, the
plane of vertical wall 111 is beyond the end edge 117 of horizontal
wall 84. Likewise, the plane of vertical wall 85 is beyond the end
edge 118 of horizontal wall 110. Also, vertical walls 85 and 111
have a height less than the diameter of portion 6. By so
dimensioning the respective horizontal and vertical walls of the
connector elements, the connector elements of each set are in
non-engaging relationship to each other which facilitates both
handling and positioning the connector elements on the respective
horizontal portions of the leg units when the connector elements
are welded to the leg units. In addition, the arcuately curved end
edges 90 and 91 of each connector element engage the horizontal
portions of the leg units, and the horizontal portions are thus
spaced apart arcuately. As shown at FIGS. 3 and 10, the respective
connector sets 15 and 16 are offset toward opposite sides of the
chair, but are slightly inwardly of the respective side walls 46
and 47 of the seat structure 3.
Seat structure 3 is secured to base structure 2 with connector
brackets 23 and 24. As shown at FIG. 8, connector bracket 24 is
formed from a single piece of heavy gauge weldable sheet metal and
has a vertical wall 125 and a short horizontal bottom lip 126 bent
at a right angle to wall 125, and which extends the length of the
lower end of the wall. The end edge 127 has an arcuately curved
upper portion 128 which conforms with the curvature of the
horizontal portion of the leg sets, and end edge 129 has a
similarly curved upper portion 130. Bent at a right angle to
vertical wall 125 is an upper wall 131. As shown at FIGS. 5 and 8,
upper wall 131 has a horizontal wall portion 132 which extends
inwardly across lip 126, and terminates as an upwardly curved wall
portion 133 which has a radius of curvature identical to the radius
of the tubes from which support elements 19 and 20 are formed.
Hence, as shown at FIG. 5, arcuate wall 133 conforms to the
curvature of support element 20 along a 90.degree. sector of the
circumference of the support element. A pair of transverse
longitudinally spaced apart projections 134 and 135 are formed in
wall 133 adjacent one of its ends, and similar projections 136 and
137 are formed in the wall 133 adjacent its other end. These
welding projections are provided to facilitate resistance welding
connector bracket 24 to the horizontal portion of support element
20 which extends beneath seat 21.
Connector bracket 23 is identical with connector bracket 24 and is
merely connector bracket 24 rotated end for end. Connector bracket
23 has a vertical wall 138, (FIG. 5) a lower lip 139, and an upper
wall with a flat portion 140 and an upwardly curved portion 141 to
which support element 19 is welded. The brackets 23 and 24 are
welded respectively to support elements 19 and 20 before the
support elements are secured to the seat shell, and the brackets
are aligned with each other transversely of the chair.
Bracket 24 is so dimensioned that the distance between the inside
surface of horizontal wall 132 and the inside surface of lip 126 is
only slightly greater than the distance between the outside surface
of horizontal wall 114 and the outside surface of horizontal leg
112 of connector set 16. Hence, connector bracket 24 can readily be
slipped over the connector elements of connector set 16 to the
position shown at FIGS. 4 and 5. The openings 142 and 143 in
connector bracket 24 are so located that they align with the
respective openings 92 and 93 of connector element 82. The length
of horizontal wall 125 is such that connector bracket 24 is a close
fit between horizontal portions 6 and 9, and the arcuately curved
edges 128 and 130 are closely adjacent the horizontal portions.
With seat structure 3 assembled, and base structure 2 also
assembled, the seat structure can be secured to the base structure
quite readily using only a screwdriver. This is accomplished by
positioning the seat structure over the base structure and then
spreading connector brackets 23 and 24 apart a sufficient distance
that the lower lips 139 and 126 of the respective connector
brackets clear the outside surfaces of the vertical walls 85 and
113 of the respective connector sets 15 and 16. The seat structure
is then pushed downwardly until lips 139 and 126 snap across the
bottom surface of the horizontal legs of the outside connector
element of each connector set. With the connector brackets so
positioned, it will be observed that flat upper wall 140 of
connector bracket 23 rests on the top surface of horizontal wall
110 of connector element 81 at one side of the chair, and that flat
wall 132 of connector bracket 24 rests on the top surface of
horizontal wall 114 of connector element 83, at the other side of
the chair. Machine screws 145 are then inserted through the
openings in the connector brackets and are threaded into openings
92 and 93 of the outside connector element of each set to secure
the seat structure to the base structure. Since no special tools,
other than a screwdriver, are required to secure the base structure
to the seat structure, the chair can be shipped in a knocked-down
condition with the base structure separated from the seat
structure. Because of the shape of the seat structure, several seat
structures can be shipped in the same carton to the desired
destination in nested relation to each other. Similarly, a group of
base structures 2 can be nested one on the other and shipped in a
separate carton to the same destination. At the destination, the
seat structure is assembled to the base structure, which can be
done by unskilled labor, since it merely entails inserting four
screws through the connector brackets into the outside connector
elements.
It is believed that the remarkable comfort characteristics of the
chair of this invention reside in the configuration of the
seat-back shell 18 and the cooperation of the shell with support
elements 19 and 20 to provide some flexture of the back relative to
the seat, especially at the juncture 40 of the seat 21 and back
22.
As shown at FIG. 10, the front surface 41 of the back is comprised
of two substantially flat surfaces 150 and 151 which extend toward
each other from the opposite side walls 25 and 26 of the back and
merge with each other at the vertical center of the back to provide
a shallow V-shaped spine relief area 152 along the vertical center
of the front surface 41. As shown at FIG. 12, the angle between
surfaces 150 and 151 is approximately 160.degree. at a location
spaced slightly from top edge 27 of back 22. At the very top of the
chair, the angle is slightly larger, approximately 162.degree.. The
angle between surfaces 150 and 151 decreases in a direction toward
opening 32. As shown at FIG. 11, the angle between surfaces 150 and
151 is 150.degree. at a location somewhat above the apex 36 of
opening 32. At the opening, the angle between surfaces 150 and 151
is even smaller, approximately 145.degree.. Hence, at the
intersection of surfaces 150 and 151 adjacent the top edge 27 of
back 22, the back is flatter than it is at a lower position along
the back, and the angle between the surfaces becomes the sharpest
at the apex of opening 32.
As shown at FIG. 13, the center of the back is substantially
straight along its length from the apex 36 of opening 32 to the top
edge 27 of the back. FIG. 13 shows an additional feature of the
seat-back shell which is also believed to enhance the comfort of
the shell. It will be observed that the upper surface 37 of seat 21
slopes downwardly in a direction away from front portion 44 of the
seat and this slope is substantially uniform along the length of
surface 37. In contrast, the upper edge of side wall 42 of the seat
extends horizontally from front portion 44 of the seat to the
back.
As shown at FIG. 14, surface 37 curves upwardly from the center 154
of the seat toward the juncture of surface 37 with wall 42. With
reference to FIG. 15, it will be noted that the upward curvature of
the surface 37 becomes shallower in a direction toward front 44 of
the seat. Then, at the junction where surface 37 merges with front
portion 44 of the seat, the surface 37 is horizontal, as shown at
FIG. 16. Although only one-half of the seat is shown in FIGS.
14-16, the seat is symmetrical about a vertical plane, and the
other half of the seat is therefore the mirror image of the half
shown at FIGS. 14-16.
It is believed that the upwardly curved or dished upper surface 37
of the seat which becomes more shallow and ultimately terminates at
a straight surface adjacent the front of the seat is instrumental
in providing comfort for the buttocks and thighs of a student
sitting on seat shell 18, and that the spine relief area 152 formed
adjacent the intersecting planar surfaces 150 and 151 of the rear
of the seat cooperate with the surface 37 and the buttocks relief
opening 36 to provide a seat construction which, although formed
from rigid molded plastic material, provides for extreme comfort of
even lanky students. An additional comfort feature is that the
shell is so constructed adjacent the juncture of the back and the
seat, and the tubular supports 19 and 20 are so arranged that some
flexing or give is available both along back 22 and at the juncture
of the back 22 with seat 21.
If desired, the basic chair 1, including the seat structure and
base structure, may be provided with a tablet arm or desk arm
assembly 160 shown at FIGS. 17 and 18. Tablet arm assembly 160
includes a flat desk panel 161 having a smooth top or writing
surface 162, a tubular arm support 163, which extends under and is
secured to the desk panel, and arm support brackets 164 and 165
which secure the desk assembly to the base structure of the
chair.
As shown at FIGS. 17 and 18, arm support element 163 has a lower
horizontal portion 166 which extends under the chair seat and below
the connector sets 15 and 16. The arm support element is bent as at
167 along a relatively long radius to provide an intermediate
section 167' which extends upwardly and forwardly to the under-side
of the desk panel. At the under-side of the desk panel, the arm
support is bent again so it extends first forwardly and slightly
upwardly, as at portion 168, along the bottom surface 169 of desk
panel 161, and then at a right angle to portion 168 to provide
upper end 170 which extends transversely of desk panel 161 in
parallel relation to but spaced from the front edge 171 of the
panel. The desk panel is secured to the tubular support with a
plurality of U-shaped connector clips 172-175, each having a pair
of outwardly projecting flanges 176, 177. Each flange is provided
with an opening to receive a screw 178 which is threaded into the
panel from its underside to secure the panel to the arm
support.
FIG. 19 shows that arm support bracket 164 has a flat rectangular
upper vertical wall 180 which terminates at its upper end at a
narrow inwardly extending horizontal wall or lip 181. Support
bracket 164 also has a flat triangular lower vertical wall 182
joined to vertical wall 180 by a narrow horizontal wall 183. Formed
in upper vertical wall 180 are a pair of spaced-apart openings 184
which align with the openings 92 and 93 of the outside connector
element of connector set 16, and with the openings in connector
bracket 24. Formed in lower wall 182 is an opening 185 of a
diameter to receive the lower tubular portion 166 of the desk arm
support 163.
Arm support bracket 165 is quite similar to bracket 164. Arm
support bracket 165 has an upper vertical wall 186 joined to a
lower vertical wall 187 by a narrow horizontal connecting wall 188.
There is, however, no horizontal wall or lip like lip 181, nor is
there an opening in wall 187 to receive lower portion 166 of the
desk arm support 163. Instead, bracket 165 is welded as at 190 to
the end of lower portion 166 and closes this end. Bracket 164, on
the other hand, is slipped over lower portion 166 and is welded as
at 191.
Connector brackets 164 and 165 are connected to lower portion 166
of the desk arm support so horizontal walls 181 and 183 of bracket
164 project inwardly, and horizontal wall 188 of bracket 165 also
projects inwardly. Connector brackets 164 and 165 are aligned
transversely of the chair, and are so positioned that the distance
between inside surfaces 180 and 186 of the respective connector
brackets equals the distance between the outside surfaces of the
connector brackets 23 and 24 of the seat structure. Hence, to mount
desk arm assembly 160 on the chair, it is merely necessary to
extend lower portion 166 under the chair, pivot the arm assembly
160 so lip 181 hooks over the top edge of connector bracket 24, and
then pivot the assembly counter-clockwise as viewed at FIG. 17, so
wall 186 of connector bracket 165 is moved upwardly and adjacent
the side wall of connector bracket 23. Machine screws 145 are
inserted through connector bracket 164 and connector bracket 24 and
are threaded into the outside connector element of connector set
16, and similarly, at the other side of the chair, machine screws
145 are inserted through connector bracket 165 and connector
bracket 23 into the outside connector element of connector set 15.
Since the addition of desk arm assembly 160 is optional with the
purchaser of the chair, the desk arm can be added quite easily to
the basic chair, and hence, desk arm equipped chairs are not a
specialty item. It will also be appreciated that several desk arms
can be shipped separately in a package or carton separate from the
package or carton for the seat structure and base structure.
While a preferred embodiment of the chair of this invention has
been shown and described in detail, it is to be understood that
numerous changes and variations can be made in the details of the
construction shown and described herein without departing from the
scope of this invention. For example, the proportions of the seat
structure and base structure could be changed to suit the needs of
people of various builds and sizes, the base structure may be used
with seat structures of different types, and the seat shell can, of
course, be used with bases other than the one disclosed herein
also, without departing from the scope of this invention.
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