U.S. patent number 3,767,261 [Application Number 05/126,563] was granted by the patent office on 1973-10-23 for seating and sub-assembly for seats and backs and method for making same.
Invention is credited to David L. Rowland.
United States Patent |
3,767,261 |
Rowland |
October 23, 1973 |
**Please see images for:
( Certificate of Correction ) ** |
SEATING AND SUB-ASSEMBLY FOR SEATS AND BACKS AND METHOD FOR MAKING
SAME
Abstract
Seats and backs for chairs and other seating units are made as a
sub-assembly of sinuous spring wires. Each wire touches its
adjacent wire at least once per cycle, and each of the wires
extends when in the sub-assembly and before placed therein as a
cylindrical arc, so that the assembly itself is a cylindrical arc.
A thin sleeve-like plastic coating surrounds the wires and follows
their sinuous shapes, linking the wires together wherever they
touch or closely approach each other, to provide the unitary
assembly. In fact, the assembly is held together solely by this
plastic coating. The assembly is intended to be flattened somewhat
when installed on a chair frame, to place the springs in tension
along a flatter cylindrical arc, and this tension is one of the
main forces retaining the wires in place. The assembly, whether
coated or not, is mounted at or near the ends of the individual
wires on a suitable securing member of the frame. In preferred
forms of the invention the plastic coating has an A scale Shore
durometer between 45 and 90, so that the assembly is held together
by the plastic coating without substantially restraining the
flexing of the spring wires, while the coating also provides a
spring action itself between the adjacent wires, by stretching and
contracting, giving a two-way stretch. Front and rear border wires
may be added to the assembly if desired and held to the adjacent
sinuous wires by the plastic coating. A method for making such a
sub-assembly is shown, as is a method for installing a sub-assembly
on a suitable frame.
Inventors: |
Rowland; David L. (New York,
NY) |
Family
ID: |
22425518 |
Appl.
No.: |
05/126,563 |
Filed: |
March 22, 1971 |
Current U.S.
Class: |
297/452.64;
D6/376; 5/309; 297/239; 297/447.4; 297/452.52; 297/452.63 |
Current CPC
Class: |
A47C
7/285 (20130101); A47C 7/30 (20130101); A47C
7/282 (20130101); A47C 5/04 (20130101) |
Current International
Class: |
A47C
7/28 (20060101); A47C 5/00 (20060101); A47C
7/02 (20060101); A47C 5/04 (20060101); A47c
003/04 (); A47c 007/14 () |
Field of
Search: |
;297/239,445,450,452,454,458 ;160/386-404 ;117/99,178,128.7,133
;5/309,354 ;267/111,44,109 ;161/112,118 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Nunberg; Casmir A.
Claims
I claim:
1. A seating apparatus, including in combination:
a. a frame having at least two spaced-apart rigid frame
portions,
b. an assembly having
1. a series of arcuate continuous, sinuous wires, each wire having
two ends, each said wire closely approaching each of its
immediately adjacent said wires at frequent intervals, and
2. a thin sleevelike stretchable plastic coating surrounding said
wires, following their sinuosity and stretchably joining them
together where they closely approach each other, said approaches
being close enough for effective bridging between said wires by
said coating, said coating constituting the sole means holding said
assembly together,
3. whereby said wires and said plastic coating comprise a unitary
assembly defining a cylindrical arc that is substantially round,
and
c. mounting means separate from said coating for securing said
assembly to respective fixed locations of said rigid frame portions
and thereby preventing relative sliding movement of the wires along
said frame portions, said frame portions being so spaced apart that
installation flattens said arc to a flatter arc and places the
assembly (b) in tension, whereby resilience for seating comfort is
obtained both by the arcing and tensioning of said wires and by the
stretchability of said coating where it bridges between said
wires.
2. The seating apparatus of claim 1 wherein said frame supports two
said assemblies, one for a seat and one for a back.
3. The seating apparatus of claim 2 wherein said seat arches
upwardly from side to side and said back arches rearwardly from
side to side.
4. The seating apparatus of claim 3 wherein said frame is stackable
upon a like frame, with the arched seats nesting within each other
and the arched backs nesting within each other.
5. The seating apparatus of claim 2 wherein in each said assembly
the wires occupy a silhouette area of at least 17 percent of the
area of their assemblies, so that the sitter is supported without
undue load concentration.
6. The seating apparatus of claim 2 wherein said seat arches
upwardly from front to rear and said back arches forwardly from
bottom to top.
7. The seating apparatus of claim 2 wherein said frame is curved
and each said assembly is attached to the frame curves so that said
seat and said back are imparted a compound curvature, enabled by
said stretchable coating and by the separateness of said wires,
especially at their ends.
8. The seating apparatus of claim 2 wherein the wires in the seat
lying closest to the forward edge of the chair are of lighter gauge
than the wires of the seat in the central portion thereof, thereby
imparting increased comfort.
9. The seating apparatus of claim 1 wherein some of said wires have
a different vibration frequency from other wires, in order to
dampen bounce.
10. The seating apparatus of claim 9 wherein some of the wires are
of different thickness than others, to afford the bounce dampening
to said assembly.
11. The seating apparatus of claim 9 wherein some of the wires are
of different configuration and curve length than others, to afford
the bounce dampening.
12. The seating apparatus of claim 9 wherein some of the wires are
of different spring temper from others, to afford the bounce
dampening.
13. The seating apparatus of claim 2 wherein said seat is arched
downwardly to provide a concave upper surface.
14. The seating apparatus of claim 1 wherein said assembly (b)
depresses 1 inch to 3 inches when sat upon by a 150-pound
person.
15. The seating apparatus of claim 1 wherein the wire diameter is
from 0.05 inch to 0.15 inch.
16. The seating apparatus of claim 1 wherein the coating thickness
is from about 20 percent to about 100 percent of the wire
thickness.
17. The seating apparatus of claim 1 wherein the empty space
between the coated wires occupies between 2 percent and 75 percent
of the area of said assembly (b), so that the sitter is supported
without undue load concentration.
18. The seating apparatus of claim 1 wherein said mounting means
comprises means for anchoring each of said spring wires adjacent
their ends, the tension under which the spring wires are placed
helping to retain them in place.
19. The seating apparatus, including in combination:
a. a frame having at least two spaced-apart rigid frame
portions,
b. an assembly having
1. a series of arcuate continuous, sinuous wires, each wire having
two ends, each said wire closely approaching each of its
immediately adjacent said wires at frequent intervals, and
2. a thin sleevelike plastic coating surrounding said wires,
following their sinuosity and joining them together where they
closely approach each other, said approaches being close enough for
effective bridging between said wires by said coating, said coating
constituting the sole means holding said assembly together,
3. whereby said wires and said plastic coating comprise a unitary
assembly defining a cylindrical arc that is substantially round,
and
c. mounting means for securing said assembly to said rigid frame
portions, said frame portions being so spaced apart that
installation flattens said arc to a flatter arc and places the
assembly (b) in tension,
said mounting means comprising means for anchoring each of said
spring wires adjacent their ends, the tension under which the
spring wires are placed helping to retain them in place,
each said mounting means engaging the actual wire ends to prevent
movement of the two ends of each said wire toward each other.
20. The seating apparatus, including in combination:
a. a frame having at least two spaced-apart rigid frame
portions,
b. an assembly having
1. a series of arcuate continuous, sinuous wires, each wire having
two ends, each said wire closely approaching each of its
immediately adjacent said wires at frequent intervals, and
2. a thin sleevelike plastic coating surrounding said wires,
following their sinuosity and joining them together where they
closely approach each other, said approaches being close enough for
effective bridging between said wires by said coating, said coating
constituting the sole means holding said assembly together,
3. where said wires and said plastic coating comprise a unitary
assembly defining a cylindrical arc that is substantially round,
and
c. mounting means for securing said assembly to said rigid frame
portions, said frame portions being so spaced apart that
installation flattens said arc to a flatter arc and places the
assembly (b) in tension,
said mounting means comprising means for anchoring each of said
spring wires adjacent their ends, the tension under which the
spring wires are placed helping to retain them in place,
each said mounting means engaging said wire at a locus spaced from
its ends, so that the ends extend beyond said mounting means and
are free.
21. The seating apparatus of claim 1 wherein said wire ends lie in
the same arc as the remainder of their wire.
22. The seating apparatus, including in combination:
a. a frame having at least two spaced-apart rigid frame
portions,
b. an assembly having
1. a series of arcuate continuous, sinuous wires, each wire having
two ends lying in the same arc as the remainder of their wire, each
said wire closely approaching each of its immediately adjacent said
wires at frequent intervals, and
2. a thin sleevelike plastic coating surrounding said wires,
following their sinuosity and joining them together where they
closely approach each other, said approaches being close enough for
effective bridging between said wires by said coating, said coating
constituting the sole means holding said assembly together,
3. whereby said wires and said plastic coating comprise a unitary
assembly defining a cylindrical arc that is substantially round,
and
c. mounting means for securing said assembly to said rigid frame
portions, said frame portions being so spaced apart that
installation flattens said arc to a flatter arc and places the
assembly (b) in tension,
said mounting means comprising a member having transversely
outwardly extending tongues to which said wire ends are engaged,
said tongues being bent down over said wires.
23. The seating apparatus of claim 22 wherein said mounting means
is arcuate and is secured to a tubular said frame member.
24. The seating apparatus of claim 22 wherein said mounting means
is an integral portion of said frame, said tongues being bent out
portions of said frame.
25. The seating apparatus of claim 22 wherein said frame is tubular
and hollow and has a lengthwise extending slot and said mounting
means lies inside the hollow tubular frame.
26. The seating apparatus, including in combination:
a. a frame having at least two spaced-apart rigid frame
portions,
b. an assembly having
1. a series of arcuate continuous, sinuous wires, each wire having
two ends lying in the same arc as the remainder of their wire, each
said wire closely approaching each of its immediately adjacent said
wires at frequent intervals, and
2. a thin sleevelike plastic coating surrounding said wires,
following their sinuosity and joining them together where they
closely approach each other, said approaches being close enough for
effective bridging between said wires by said coating, said coating
constituting the sole means holding said assembly together,
3. whereby said wires and said plastic coating comprise a unitary
assembly defining a cylindrical arc that is substantially round,
and
c. mounting means for securing said assembly to said rigid frame
portions, said frame portions being so spaced apart that
installation flattens said arc to a flatter arc and places the
assembly (b) in tension,
said mounting means comprising raised portions of said frame
providing wire-engaging means and securing means overlying said
frame and the engaged portion of said wires and secured to said
frame.
27. The seating apparatus, including in combination:
a. a frame having at least two spaced-apart rigid frame
portions,
b. an assembly having
1. a series of arcuate continuous, sinuous wires, each wire having
two ends, said wire ends being bent at a right angle to the arcs of
said wires, each said wire closely approaching each of its
immediately adjacent said wires at frequent intervals, and
2. a thin sleevelike plastic coating surrounding said wires,
following their sinuosity and joining them together where they
slosely approach each other, said approaches being close enough for
effective bridging between said wires by said coating, said coating
constituting the sole means holding said assembly together,
3. whereby said wires and said plastic coating comprise a unitary
assembly defining a cylindrical arc that is substantially round,
and
c. mounting means for securing said assembly to said rigid frame
portions, said frame portions being so spaced apart that
installation flattens said arc to a flatter arc and places the
assembly (b) in tension.
28. The seating apparatus of claim 27 wherein said mounting means
comprises openings into said frame means and means for holding
thereto wire ends inserted into said openings.
29. The seating apparatus of claim 28 wherein said means for
holding comprises a socket member in each said opening having means
for preventing retraction thereof and means for preventing
retraction of a wire end inserted in said socket member.
30. The seating apparatus of claim 29 wherein said frame is tubular
and hollow and said mounting means comprises slots in said hollow
tubular frame and a dowel-like member inside said frame engaging
said hooks and preventing retraction thereof from said frame.
31. The seating apparatus of claim 1 wherein the thicknesses of the
seat and back areas are no less than one two-hundredths and no more
than one-fiftieth the height of the seat level.
32. The seating apparatus, including in combination:
a. a frame having at least two spaced-apart rigid frame
portions,
b. an assembly having
1. a series of arcuate continuous, sinuous wires, each wire having
two ends, said wire ends each being formed into a hook extending
generally perpendicular to the arc of the remainder of the wires,
each said wire closely approaching each of its immediately adjacent
said wires at frequent intervals, and
2. a thin sleevelike plastic coating surrounding said wires,
following their sinuosity and joining them together where they
closely approach each other, said approaches being close enough for
effective bridging between said wires by said coating, said coating
constituting the sole means holding said assembly together,
3. whereby said wires and said plastic coating comprise a unitary
assembly defining a cylindrical arc that is substantially round,
and
c. mounting means for securing said assembly to said rigid frame
portions, said frame portions being so spaced apart that
installation flattens said arc to a flatter arc and places the
assembly (b) in tension.
Description
BACKGROUND OF THE INVENTION
This invention relates to an assembly for seats and backs, usable
in chairs, sofas, stools, benches, automobile and other
transportation seating and the like. The seat and back units are
sub-assemblies, applicable to any of various types of frames to
provide seating assemblies embodying the invention.
A hard seat can at best only approximate a comfortable shape since
human posteriors vary greatly. While seats theoretically might be
tailor-made for each individual, this is costly and requires
carrying the seats to wherever they are to be used. A better
solution to the problem is a seat which automatically tends to
shape itself to each user's posterior. A seat with the proper
resilience in the right places is an important object of this
invention.
The seated human body rests mainly on the ischial tuberosities, the
two lower points of the pelvis. Additionally, it rests on the meaty
and fatty flesh in a 1-inch to 2-inch radius therefrom. A flat hard
surface becomes uncomfortable quickly, because the load is
concentrated on the small area of the ischial tuberosities and the
flesh immediately covering them is compressed with great force. A
more comfortable condition can be achieved by spreading this load
over a larger area, so that the unit area compressive force is
substantially reduced. If the seat surface can be automatically
shaped to conform generally to the sitter, this desirable spreading
can be achieved. However, if a seat is too soft and the area is
spread over too wide a surface, the result is to engulf the sitter
too deeply, and this oftn results in a lack of security when the
sitter feels that he is insufficiently supported. This is one
reason why one often sees autmobiles in which the owner has gone to
the trouble of installing wooden slat accessory pads to make the
seat firmer.
Dr. Bengt Akerblom, eminent Swedish authority on human posture,
says in his book Standing and Sitting Posture, published by A. B.
Nordiska, Bokhandeln, 1948:
"Naturally a rather soft seat would distribute the pressure over
the tuberosities better than a hollowed rigid one. They are,
however, so small that there would be very little sense in having a
very soft and resilient seat. On the contrary, such a seat might be
expected to transfer a not inconsiderable proportion of the weight
onto tissues which are not adapted for bearing it. The best
consistency for the seat would therefore be such that although it
gave under pressure, it only gave slightly."
Proper resilience alone is not enough. Independent freedom of
movement of such as that found in a two-way stretchable material
more appropriately conforms to the human posterior shape, which
itself has compound curvature.
While certain spring and padding combinations can afford proper
yieldability and firmness, practically all padding materials have
the fault of being good heat insulators. In a cold room, this might
be acceptable temporarily, but people usually wear clothes
appropriate for temperature conditions anyway and to sit for any
length of time on a heat insulative material becomes uncomfortable
because of inhibition of dispersion of body heat in the human
posterior area. Then, the person squirms in order to get to a
cooler spot. Thus, anyone who, while dressed in a swimming suit,
has tried to sit down on a seat of a convertible car that has been
out in the hot sun, knows that the heat conditions of the seat can
be unbearable.
Some prior-art seats have been made from spaced-apart wires, but
the spacing of the wires has been such that too much load has been
concentrated on too few wires, and this textural discomfort has
made the use of upholstery pads requisite for such seats.
An ideal seat therefore has:
1. Proper shape, including proper compound curvature.
2. Proper resilience and firmness (resilience providing shape
adaptability to each sitter).
3. Proper heat dispersion.
4. Proper surface contact area.
An object of this invention is to provide a seat more nearly
approaching the ideal seat than has been achieved in the past.
Each unit or sub-assembly of this invention comprises a series of
sinuous spring wires, held together solely by a thin sleeve-like
plastic coating around each of the wires and bridging the wires
where they touch or very closely approach.
The invention may be considered as an improvement over my earlier
U. S. Pat. No. 2,803,293. In that patent, each of the sinuous
springs had a hook on each wire which partially encircled a rigid
frame member. This hooking did not positively prevent relative
movement of the wires to the frame, nor did it hold them in proper
position relative to each other prior to the seat's being coated
with plastic. Partly because there was only line contact at best
between the wire and the frame (and, unless the chair frame size
was exactly matched to the size of the hook, there would be contact
at only two points), the hooks tended to rotate when subjected to
force, as when someone sat on the chair. Even after the chair had
been coated with plastic, this instability was such that when the
chair was being sat upon, the wire hooks tended to walk along the
chair frame as the sitter shifted his position, thereby distorting
the seat area, with the result of making the seat
uncomfortable.
The chair of U. S. Pat. No. 2,803,293 was expensive to manufacture
because the springs had to be put on the chair frame individually,
carefully positioned there, and then either the entire chair had to
be dipped or at least the upper portion of the chair from the seat
up had to be dipped. Such dipping meant that all parts of the chair
that were dipped were coated with plastic, unless something could
be put on some parts of the chair to repel the plastic. Either
alternative added substantially to the cost. Also, the coating
dulled the appearance of chrome-metal furniture, and wood furniture
was given a rather unpleasing appearance. Each such chair had to be
made individually, and the springs themselves had to be put on to a
full chair individually, so that the easy handling required by mass
production was not possible. Also, great care had to be taken that
the springs themselves were not distorted by the spring
manufacturer during his manufacture; otherwise, the springs could
not be properly bridged across by the plastic.
These difficulties are overcome in the present invention, which
makes mass production quite feasible. Only the sub-assembly that is
to constitute a seat unit or back unit is dipped, and this
sub-asembly is relatively inexpensive and its manufacture is
capable of automation and other mechanical aids. A very important
feature is a provision of a sub-assembly capable of use on a wide
variety of frames for different kinds and designs of seating units.
The same sub-assembly may be sold to various manufacturers for
incorporation into any of the wide variety of frames.
Another disadvantage of my prior chair was that the chair seat and
back were substantially planar, and, even if they did have a slight
bowing, they were installed in a generally flat, at-rest shape of
the spring, so that there was little spring tension or cushioning
action. In the present invention, it becomes possible to obtain
much more tension. cushioning, and resilient support from the
springs by virtue of making the subassembly as a cylindrical
segment that is somewhat flattened when it is put on the chair
frame, rather than making the chairs from a series of substantially
flat springs. The tension of the wires pulling inwardly is the main
force retaining the wires and the assembly.
Another important feature of the invention is the provision of a
two-way stretch, which is obtained by using plastic coatings lying
within a prescribed range of Shore A durometers. The springs can
continue their flexing in the usual manner, without being overly
limited by the coating, and also the spring assembly can flex and
stretch the plastic when it bridges the wires. In the prior patent,
it was possible to use a wide variety of materials, including hard
plastics such as nylon which would certainly hold the wires
together but would not themselves stretch, so that all the stretch
had to be accomplished by the wires when such material was used.
While this gave the seat some yieldability, it resulted in
retaining a flat or somewhat cylindrical surface rather than giving
a compound curve, which is obtained when sitting on a cylindrical
arched seat that has two-way stretch. No two-way stretch was
recognized or found in this type of chair until a desired range of
durometers was discovered in this invention and used in proper
relationship to suitable gauges of wires to enable achievement of
this goal.
Even two-way stretchability and proper wire gauge alone have been
found to be insufficient. Resistance to bounciness is an important
property when considering the resilience necessary for a
comfortable seat, and it is especially necessary in transportation
seating where up-and-down motion tends to result in harmonic
vibration, for harmonic vibrations subject the sitter to vertical
oscillations for some time after a bump is traversed.
Bounce-dampening is thus requisite and is partly accomplished in
the present invention by proper choice of durometer of the plastic
coating. More bounce-dampening can be achieved in this invention by
variations in gauge or shape of some of the adjacent wires. If the
durometer is too low a value, the springs are too free and are too
ready to bounce. If the durometer is too high, the seat is too
stiff and lacks the proper two-way stretch quality desired. Proper
choice of durometer according to the principles of this invention
enables the plastic to serve as a shock absorber and provides a
snubbing action against bounce. Also, by making some of the wires
different from others in gauge or shape, their harmonic vibration
periods are made different, and they then help to provide a
snubbing action.
The amount of the seating area occupied by the metal thickness and
the thickness of the plastic coating are also important features to
be considered, and little, if any, thought about these features is
evident in the prior art. For example, in the drawings for U. S.
Pat. No. 2,803,293, it can be shown that the metal occupies only
about 14 percent of the silhouette of the area, whereas I have now
found that for proper results the spring's steel should occupy a
minimum of 17 percent of the silhouette of the area and a maximum
of about 75 percent, with the range of 17 to 25 percent preferable
generally. The coating should generally be about one-half as thick
as the wire in order to give bridging, proper heat insulation and
proper stretchability, but a range from about one-fifth of the wire
thickness to about equal to the wire thickness can be used. Also
the size of the void areas between the coated wires should be no
greater than about 75 percent of the seat area used to accommodate
one adult sitter and should not be less than about 2 percent, with
about 60 to 75 percent being preferable.
SUMMARY OF THE INVENTION
The present invention comprises a seat or back sub-assembly which
can be secured to various frames in various manners. Basically the
sub-assembly is a cylindrical segment later flattened somewhat upon
installation. The sub-assembly thus comprises a series of arcuate,
continuous, sinuous, spring metal wires, each of the wires closely
approaching each of its immediately adjacent wires at frequent
intervals. A thin sleeve-like plastic coating surrounds the wires,
follows their sinuosity, and joins them together where they closely
approach each other, effecting bridging between them at these close
approaches. The wires and plastic coating comprises a unitary
assembly defining the cylindrical arc which is intended to be
flattened somewhat when the assembly is installed on a frame,
thereby placing the springs in tension along a flatter cylindrical
arc. This tension helps to hold the wires in place and to give
springiness and resilience to the assembly. The coating constitutes
the sole means holding the assembly together. The ends of the wires
(or portions near the ends) are used to attach the sub-assembly to
a frame, with the aid of suitable securing members. Rim members or
border wires may be provided, especially if the sinuous wires have
so much amplitude that they tend to provide a series of projections
and recesses along the front edge of the chair which might tend to
snag some clothing. The rim members are part of the assembly and
are joined to their adjacent sinuous wires by the plastic
coating.
A very important feature of the invention, which is not obtainable
in structures where the wires are secured rigidly to a rim or
surrounding frame, is that the assembly is capable of stretch
everywhere, including along the edges, so that it becomes possible
to obtain stretching right up to and including the edge of the seat
or back. This capability is especially useful in installing the
assembly on a frame having curved portions.
Since the wires are held together only by the plastic, it is
important in the manufacture of the assembly to have suitable means
for holding the wires in proper shape before and while they are
dipped and until the coating is cured. This may be done by
attaching each of them to a frame member which is dipped and then
cut away, but since this wastes metal, the invention includes frame
means for holding the wires and later releasing them from the
frames. For this purpose, the free ends of the wires may not be
coated at all, being held above the dipping solution that applies
the coating, or they may be coated if that is desired.
Similarly, when the sub-assemblies are to be installed on the
chair, it is desirable to have a tool for making the installation,
stretching the ends apart and flattening the assembly and enabling
the ends of the wires to be individually secured to suitable means
on the frame.
When the assembly is installed as a seat, the rise from one end to
another after flattening is preferably between a quarter of an inch
and an inch. For the back, the curvature may be somewhat greater,
preferably a radius of seven to eleven inches. The plastic,
preferably, is in the range of between 45 and 90 Shore A durometer
and seems to be best at about 75, so that the two-way stretch
action previously referred to is attained.
A feature of the invention is that the wires cannot go straight
across. They must undulate in order to be stretchable and they must
be connected to each other by stretchable means, i.e., the coating
within the desired range of durometers. This contrasts with my
earlier patent which may allow flexible joints but does not require
stretchable joints. Nor does it describe how to obtain them. A
150-lb. person sitting normally on the chair of the present
invention will depress it by at least 1 inch (or at least
one-eighteenth part of seat height) and at most by about 3 inches
(about one-sixth part of seat height). As stated, the junctures are
stretchable and flexible, but they are also tough, so that they
cannot be pulled apart under the usual sitting conditions. Thus,
while putty and kneaded erasers have a rubbery quality, they do not
have the elasticity, stretchability, flexibility or resilience
requisite in the coating used in this invention.
To get the best results in this invention, the area of the
silhouette of the wires prior to coating should be at least 17
percent of the seat area, especially on a typical area. For
sufficient bridging, heat insulation, and surface cushioning, the
coating should be at least about 20 percent of the wire diameter.
If the seat were made from springs alone, the comfort would be
insufficient, particularly when used in moving vehicles, for it
would be too bouncy. Proper durometer and proper thickness of the
coating relative to the wire thickness help to prevent this
bounciness. The reason they do this is similar to the reason that a
car is not comfortable with metal springs alone; it also needs the
rubber, air, and hydraulic fluid in the combination of rubber
pneumatic tires and hydraulic shock absorbers before it can be
comfortable.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of the invention will appear from the
descrption of some embodiments of the invention, which will be
described with reference to the following drawings.
FIG. 1 is a view in perspective of a chair embodying the principles
of the invention.
FIG. 2 is a view in perspective on an enlarged scale of a seat or
back unit or sub-assembly embodying the principles of the
invention, the sub-assembly being shown before it is installed on
the chair frame of FIG. 1 and while it has its natural cylindrical
arc.
FIG. 3 is a diagrammatic view in end elevation, showing the
difference in radii of the cylindrical assembly of FIG.2 and the
installed seat of FIG. 1, where the arc has been somewhat flattened
out, thereby placing the spring wires under tension.
FIG. 4 is an enlarged top plan diagrammatic view in two halves
illustrating the two-way stretch effect of the sub-assembly.
FIG. 5 is a fragmentary view in perspective of a portion of a seat
assembly of the invention installed on a chair as the seat thereof
and showing a corner near the rear of the seat. This view
illustrates the adaptability of the invention to double curvature
in the seat, as occasioned by curvature of the supporting
frame.
FIG. 6 is a fragmentary enlarged view in perspective of a front
corner portion of the chair of FIG. 1 with the sub-assembly
somewhat flattened out and partially installed on the chair frame.
Most of the brackets have been bent down into shape, but one of
them is shown before being moved to its locking position.
FIG. 7 is an enlarged view in section taken along the line 7--7 of
FIG. 6.
FIG. 8 is a view similar to FIG. 6 of a modified form of the
invention. Some parts have been broken off or broken away to show
the structure more clearly.
FIG. 9 is an enlarged view in section taken along the line 9--9 in
FIG. 8.
FIG. 10 is a view similar to FIG. 9 of a modified form of
installation of the end of one spring, this time on a wooden
frame.
FIG. 11 is a view similar to FIG. 6 of another modified form of
installation and a modified form of sub-assembly, as well as a
modified form of securing member and frame.
FIG. 12 is a somewhat enlarged view in section taken along the line
12--12 in FIG. 11.
FIG. 13 is a view similar to FIG. 6 of another modified form of the
invention with the wire ends of the sub-assembly being hook-shaped
and with a different form of attaching means to the chair frame
being shown.
FIG. 14 is a somewhat enlarged view taken along the line 14--14 in
FIG. 13.
FIG. 15 is a view similar to FIG. 6 of another modified form of
installation, with the sub-assembly like that of FIG. 6 but with
the frame and frame securement different.
FIG. 16 is a view in section taken along the line 16--16 in FIG.
15.
FIG. 17 is a fragmentary view in perspective generally similar to
those described above but showing an opposite end portion of a seat
with a sub-assembly like that of FIG. 2 installed in a different
type of chair frame and anchor installation. Parts are broken away
and shown in section.
FIG. 18 is an enlarged view in section taken along the line 18--18
in FIG. 17.
FIG. 19 is a view in end elevation of a tool being used to hold the
sub-assembly during dipping in a solution of plastic that provides
the coating.
FIG. 20 is a view in perspective of the tool of FIG. 19 with part
of the sub-assembly shown and part of it broken away. The
sub-assembly is shown in tensed position read for assembly onto a
chair frame.
FIG. 21 is a view in side elevation of the tool of FIG. 19, showing
its use in installing the sub-assembly on a chair frame. The upper
portion of the chair frame is broken away to conserve space.
FIG. 22 is a view in side elevation of two compactly stackable
chairs embodying the principles of the invention shown stacked on
each other and showing how the seat and back nest. A portion of the
back of the lower chair is broken away to show the back of the
upper chair and the relationship between the two.
FIG. 23 is a diagrammatic view showing how the two backs fit
together in FIG. 22 and showing the relationship between the chord
of the back of the lower chair and the arc of the back of the upper
chair.
FIG. 24 is a view in perspective of a modified form of chair
embodying the principles of the invention.
FIG. 25 is a view in end elevation of a sub-assembly generally like
that of FIG. 2, as used in the chair of FIG. 24.
FIG. 26 is a view in side elevation of another modified form of
chair embodying the principles of the invention.
FIG. 27 is a view in end elevation of a unit sub-assembly for the
seat of the chair of FIG. 26.
FIG. 28 is an enlarged view in section of the fastening of the
sub-assembly for either FIG. 24 or FIG. 26 to the chair frame in
those views.
FIGS. 29 to 37 are all top plan fragmentary views of various
patterns of the arcuate sinuous members; in each instance portions
of wire are shown uncovered. Plastic links the adjacent spring
members together. Various patterns are shown as illustrative of the
many many more that are possible in this invention.
FIG. 38 is a view in front elevation of the lower portion of a
modified form of chair embodying the principles of the
invention.
FIG. 39 is a view in side elevation of a stool embodying the
principles of the invention in another modified form.
DESCRIPTION OF SOME PREFERRED EMBODIMENTS
An Example of a Chair Embodying the Invention (FIG. 1)
Many many types of seating units may embody the principles of this
invention, including chairs, sofas, daven-ports, benches, stools,
automobile seats, bus seats, camp chairs and so on.
A chair 40 is shown in FIG. 1 for the purpose of giving one example
of a type of seating unit that can embody the principles of the
invention. This example is not to be construed as representing all
types of seating units, or even all types of chairs which can be
used with the present invention, for they may vary greatly in
frame, structure, appearance and so on. The basic part of this
invention is concerned with the seating and back units more than
with the framework of the chairs themselves.
The chair 40 has front legs 41 and 42 and rear legs 43 and 44 which
continue up, preferably at an angle, to form back frame portions 45
and 46, preferably having some curvature. The number of pieces used
in making the chair frame is immaterial to this invention, and
whether the frame is continuous or whether the pieces are welded or
otherwise secured together does not matter so far as the present
invention is concerned. Generally horizontal side frame portions 47
and 48 join the front legs 41 and 42 to the rear legs 43 and 44
where they meet the back frame portions 45 and 46. The frame
members 47 and 48 may have some curvature, the effect of which will
be referred to later. A seat unit 50 is supported by the side frame
portions 47 and 48, and a back unit 50A is supported by the frame
portions 45 and 46. The seat unit 50 and the back unit 50A are very
similar to each other and in some instances may be identical, but
usually the back unit 50A is somewhat smaller than the seat unit
50, and it is usually made from a smaller gauge of wire.
The chair of FIG. 1 is completed by a pair of transversely
extending members 51 and 52 which serve to rigidly space the two
sides of the chair apart. The particular form and placing of the
bracing or transverse members is not significant in the present
invention, though, of course, there must be some rigid means for
holding the frame portions 47 and 48 apart and for holding the
frame portions 45 and 46 apart. In the particular form of the
invention shown in FIG. 1, the back frame portions 45 and 46 are
rigidly held parallel to each other, and the side frame portions 47
and 48 are rigidly held parallel to each other. This parallelism
need not always be present, though it is preferred.
An important feature of the invention is the ability of the seat
assembly 50 and the back assembly 50A to accommodate themselves to
the curvature, respectively in the frame portions 47 and 48 and in
the frame portions 45 and 46. Their ability to follow this
curvature is due to the use of the two-way stretch of this
invention, all the way to the edges, as will be discussed later. It
is important here to call it to the attention of the reader,
because it is something that cannot be done with most assemblies of
this kind, since a seat or back assembly must be free to stretch
right up to its edges in order to make this particular embodiment
feasible.
The Seat Unit 50 (FIG. 2)
FIG. 2 shows the seat unit 50 before it is incorporated into the
chair 40. The view also represents basically what the unit 50A
looks like, although the unit 50A may be different in size, or even
in structure or appearance where that is desired.
In this example the sub-assembly 50 comprises a series of sinuous
spring wires 55, 55a, 55b, . . . 55n each of which is naturally
arched into a circular arc of the same size and shape. As a result,
the assembly 50 is a cylindrical segment or arc. These springs 55,
55a, etc., may have any of many different shapes, some of which are
shown in FIGS. 29 to 37. They may be of the type often called
"non-sagging springs" sometimes sold under the trademark "No-Sag;"
each spring has two free ends 56 and 57. Typical wires of this type
are of spring steel, having 0.60 to 0.75 percent carbon and 0.90 to
1.20 percent manganese. Tensile strength typically runs about
215,000 to 265,000 p.s.i., and their Rockwell hardness is about
39-41 RC range. The diameter of the wires 55 preferably lies in the
range of 0.05 to 0.15 inch. Too thick a wire tends to concentrate
the stiffness too much and the seat is too firm, while too thin a
wire makes the seat too soft.
The spring members 55, 55a, 55b, . . . 55n are placed tangent to
each other, two extreme wires 55 and 55n lying at or near the ends
or edges of the assembly. However, in this particular embodiment,
though it is not always necessary, a pair of circularly arched
spring wire members 58 are 59 are shown lying tangent,
respectively, to the wires 55 and 55n. The wire 58 thus closes off
the loop of and lies tangent to the wire 55 and makes a circular
shape, so that there are no projections that might tend to catch on
clothing, and the same is true of the wire 59 that lies tangent to
the wire 55n.
Each wire 55 touches its adjacent wires at least once per cycle.
The touching may be actual contact or may be approximate touching
or close approach, because, as will be seen, the assembly 50 is
held together in a way that does not require actual physical
contact of the wires 55 at each point of tangency. However, there
is always a very close relationship if not an actual touching. The
wires 58 and 59 become respectively the front and rear edges of the
seat 50, and this takes place on installation. The free edges 56
and 57 lie along the sides of the seat 50 and are fastened to the
chair frame, as will be seen.
A thin sleeve-like plastic coating 60 surrounds the spring wires
55, follows their sinuous shape and bridges the wires 55, 55a,
etc., where they substantially touch each other. Preferably, the
plastic coating 60 is about one-half the wire thickness, or in the
range of one-fifth of wire thickness to about equal to the wire
thickness. At the junctures, the thickness may be mostly greater,
though the wires themselves may touch. The plastic coating 60 also
surrounds the border wires 58 and 59 and links them to their
adjacent wires 55 and 55n. This plastic coating 60 thus joins the
entire sub-assembly 50 together, and in fact, it is what makes it a
sub-assembly. It holds the wires 55 etc., to each other as they
span between their ends and it holds the border wires 58 and 59 to
the extreme springs 55 and 55n at each point of tangency. The
result is the arcuate or cylindrical arc-shape, typically like that
shown in FIG. 2, although the arc may be somewhat flatter or
somewhat rounder.
Thus, the complete assembly 50 is a unit which can be sold or
shipped as a unit and can be assembled to the chair 40 of FIG. 1 or
to many other kinds of chairs, so long as the proper size and shape
is accommodated for in one way or another, that is, either by the
chair itself being sized to go with the seat unit 50 or the seat
unit 50 itself being made so that it will go with the chair frame
or other type of seating unit frame. The unit 50 by itself is
capable of mass production and is easily assembled into a chair or
other seating unit by securing the two ends 56 and 57 of each wire
55 etc., to a suitable rigid frame.
The Significance of Flattening the Cylindrical Arc (FIG. 3)
FIG. 3 shows diagrammatically what happens when the unit 50 of FIG.
2 is put into the chair 40 of FIG. 1. The round cylindrical arc of
FIG. 2 with radius R1 is flattened from the shape shown at the
bottom of FIG. 3 to the shape shown at the top of FIG. 3 where it
has a larger radius R2. The unit 50 then has a broader span, and
its arc is somewhat flattened so that it can be used as a seat. It
has a crown height h shown on the drawing, and it is still a
cylindrical arc, though much flatter.
This flattening of a round assembly is an important feature of the
invention. By forming the unit 50 initially as a cylindrical arc,
which is quite round and fairly well closed, and then flattening it
considerably, a large amount of desirable tension is placed into
the completed unit 50 so that the seat has a springy feed to it,
acting substantially as though there was a large cushion instead of
simply an assembly of thin springs. The exact amount of crown
height h or of curvature depends, of course, somewhat on taste, but
generally there will be about a maximum of 1-inch crown height h in
a 16-inch wide seating unit 50, and the proportion is usually best
considered as being a crown height h of one-sixty-fourth to
one-sixteenth of the span.
The amount of force required to flatten a seat of typical dining
chair size is important as well. For purposes of the present
invention, it has been found that a collection of springs in an
assembly 50 requiring a force of between 340 pounds and 680 pounds
to flatten it gives the seat a proper tension, and preferably the
amount is around 500 pounds. This is the force exerted in pulling
the two ends 56 etc., and 57 etc., apart to an appropriate distance
to fit onto the chair frame portions 47 and 48.
For the chair back, somewhat different rules apply, and it will be
noticed that in the chair in FIG. 1, as in most such chairs, the
arc of the back 50A extends rearwardly and is not something that
the sitter tends to flatten; rather, he tends to increase the arc
curvature, reducing its radius.
In both the seat and the back, the tension of the wires pulling
inwardly, resulting from flattening, is the main force retaining
the wires.
Significance of the Plastic Coating 60 (FIGS. 4 and 5)
The plastic coating 60 may be chosen from various types of plastic,
such as polyvinyl acetate, polyvinyl chloride, mixtures thereof,
other vinyl compounds, polyethylene, butadiene, acrylic elastomers
and so on. The material may be transparent where that is desired or
may be opaque and impart its own color to the unit. It may contain
dye or pigment which imparts the desired color, completely
preventing view of the wires 55 themselves and giving the
appearance of constituting the actual seating material. The plastic
coating 60 may be semi-transparent and may give shade or tone to
the overall color.
In this invention the plastic is confined to the unit 50 or 50A and
is not applied at all to the chair frame, so that the chair frame
may have any surface or treatment that is desired without
interference from the nature of the plastic coating.
The sinuous wires 55 are not welded to each other at their points
of tengency but are held together only by the plastic coating 60,
with the wires 55 either touching each other or even slightly apart
but closely approaching each other. The same is true of the
connection between the wires 55 and the arcuate border wires 58 and
59.
An important feature of the plastic coating 60 is that by choosing
the proper range of durometer, a two-way stretch effect can be
obtained, as illustrated in FIGS. 4 and 5. The springs 55 not only
stretch in the well-known manner of non-sagging springs, but in the
present invention the plastic coating 60 between the adjacent
springs 55 also may be stretched, and this two-way stretch effect
gives a wide range of resilience to the seat 50. If the plastic 60
is too hard, there can be substantially no such stretch, and if the
plastic 60 is too soft, there will be too much stretch, and the
springs 55 themselves are not availed of properly so that the unit
50 may even be torn apart after some use. By holding the Shore A
durometer of the plastic coating within critical values, the effect
is right with sufficient rigidity so that the springs 55 are taken
advantage of and so that they are held apart with sufficient
resilience so that the whole is not encased in a rigid cover. I
have found that the durometer range necessary to achieve this
critical range is from about 45 to about 90 Shore A scale
duro-meter, with a preferable value of about 75.
In FIG. 4 there are two portions. The left portion illustrates part
of the seat 50 before it is sat upon, with the springs 55 therefore
in their normal configuration. A typical area 61 is shown outlined,
this area comprising one complete cycle of wires 55, so that it is
representative of the total area of the seat 50 so far as the
percentage of metal silhouette per total area is concerned. This
area can therefore be used for determining accurately the
silhouette of the wire and its average occupation of the seat area.
Taking the gauge or wire diameter as G, the length of the wire can
be determined in terms of G by measuring the length of the center
lines of all the wires 55 in the area 61 in terms of G, and the
value is found to be 34G. The area 61 itself measures 14.6G by
10.7G, which is 156.22 G.sup.2. The silhouette area of the wire in
the area 61 is 34G.sup.2, which is 21.76 percent of the area 61.
This value lies within the range of 17 and 75 percent of the seat
area mentioned earlier, the preferred range being about 17 percent
to about 25 percent.
Also, the empty spaces between the coated wires should be no
greater than about 75 percent and no less than about 2 percent of
the area of the seat surface, and the range of about 60 to 75
percent is preferred. The minimum of about 2 percent is to provide
sufficient air ventilation.
The wires 55 in the seat 50 lie closely adjacent each other and
nearly touch at points of near tangency, where the distance D1
between them may be as low as zero, as shown in FIG. 4 and where
the overall distance from the outside to the outside is T1. The
plastic coating 60 forms a bridge fastening the wires 55 together
at 62 and has a thickness t.
The right portion of FIG. 4 illustrates what happens when the seat
50 is stretched, as when it is sat upon or when installing the
assembly on to the frame. The length L1 in the left portion extends
to the longer length L2 in the right portion. The width W1 in the
left portion extends also to become the width W2 in the right
portion. The distance D1 in the left portion has stretched to
become the distance D2 in the right portion, and the distance T1
has become the distance T2. Thus is seen the importance of the
bridge or juncture 62 and of the stretchability of the plastic 60
at this bridge or juncture 62. This of course is also related to
the thickness t of the plastic coating 60.
A glance at the seat 50 might lead one to conclude that the surface
configuration would be texturally uncomfortable. However, this
conclusion would be mistaken, for the seat 50 acts differently than
one might at first conclude for the following reasons:
1. The average occupation by the wire of the typical area (i.e., at
least 17 percent) is so great that the human posterior is supported
without concentrating the load too much. In contrast, if the wire
occupies less than about 17 percent of the area (e.g., the 14.4
occupation of the FIG. 2 area in U. S. Pat. No. 2,803,293), the
seat would be texturally uncomfortable.
2. The empty spaces constitute at least 2 percent of the seat area,
in order to give sufficient air ventilation, and preferably occupy
much more of the seat area, up to about 75 percent.
3. The wire 55 is not exposed bare metal, which would be highly
heat conductive and therefore unpleasant and uncomfortable. The
wire 55 is adequately coated with plastic 60, which is low in heat
conductivity; so it is pleasant and comfortable to sit upon.
4. The coating 60 lies within the range of Shore A durometer (45 to
90) where it is neither too hard nor too soft; in fact it tends in
itself to provide some cushioning effect and its action at the
bridges 62 adds to the comfort. Without this, the seat 50 could be
too hard or too soft.
5. The two-way stretch discussed above provides automatic
contouring, offering minimal resistance to the human posterior.
Without this two-way stretch, the seat 50 might become increasingly
uncomfortable.
In this invention the two-way stretch phenomenon extends over the
entire assembly 50 or 50A. In assemblies not of this invention
where the ends of the wires are held rigidly either to the seat
frame or to a sub-assembly rim or frame, the action is different.
In this invention the installed seat may be held rigidly at the
ends but during installation it is possible to obtain a stretch
along the ends or edges, which would be impossible if the unit were
rigid at its edges or near there or if the springs had to be
installed on the chair frame before they were dipped. It is clearly
apparent that if the assemblies are held rigidly at the edges, they
cannot be stretched there. The effect of having to be installed as
an assembly after coating may be less apparent; to understand why
it is important to install the assembly as a unit, it is first
necessary to see that it is important for the plastic to bridge
across the wires at their points of tangency, and then to note that
it is not feasible to attach the wire members to the frame in such
a way that they become too far apart to be bridged by the plastic
upon dipping.
It is not desirable to fill in all the openings with plastic. It is
very important, in fact, to have openings through the chair seat
and back and to have the coating confined to the areas immediately
around the wire and not to extend across between them, because then
the seat would become a heat insulative barrier, and the chair
would become uncomfortable.
In the present invention, the assembly is made so that the only
thing holding the wires together is the plastic and the assembly is
made separate from the chair; so it becomes possible to install the
wire ends as shown in FIG. 5 into positions where even upon initial
installation there is some stretching of the unit 50, and the
stretching may be different at some points than others due to this
expedient. Thus, as shown in FIG. 5, the unit 50 is shown with one
part of it stretched so that the adjacent wires are definitely
apart from each other, with the plastic coating providing the
stretch at the junctures. Thus, it is the plastic that provides the
stretch and not the spring wires themselves, as shown by the
stretching at T2, T3, and T4; due to that, quite a different type
of action is obtained than where the reliance has to be made upon
the spring wires, which would tend to provide considerably more
tension and an undesirable amount of tension at some points. While
the ends 56 of the wires 55 in FIG. 5 are held rigidly after they
are installed, and they cannot then slip or slide along the chair
frame portion 48, nevertheless, the installation itself achieves a
result different than where the assembly and frame both have to be
without curvature upon installation and where any desired curvature
would have to be later applied. The frame portion 48 is curved, and
the seat 50 is able to take this curvature by virtue of having no
rigid fastening any place but by the entire assembly being held
together only by the plastic coating 60. This is the significance
of the frame curvatures shown in FIG. 1 in the frame portions 45,
46, 47, and 48. Not only are frame curvatures prior to assembly
thereby enabled, but also increased comfort for the sitter is
thereby obtainable.
Friction Fastening of the Wires to the Rim (FIGS. 1 and 5-7)
Many means of fastening the spring ends 56 and 57 to a frame member
may be employed. Some of them are illustrated in the drawings in
order to give some idea of the wide variations that are possible
under this invention, but of course there are many others that
could not be shown without the specification becoming too long.
In FIGS. 1, 5, 6, and 7 the frame member 48 is provided with a
securing member 65 which is a cylindrical segment, as seen in cross
section, and has a main body portion 66 that may be welded to the
frame member 48, a similar one being welded to the frame member 47.
A series of projecting tongues 67 are provided, which may be
initially bent up as shown at the left in FIG. 6 and then bent down
into place as shown on the right, after the wire ends 56 have been
approximately positioned so as to lock the wire ends 56 into place
firmly by the members 67, clamping them between the members 67 and
the frame 48. As shown in FIG. 5, this may extend along a curve or
as shown in FIG. 6, it may extend along a straight line. Both are
equally possible in the present invention, and this is a very
important and unique effect of the present invention. It will be
seen that with the members 65 welded on the frame members 47 and
48, installation is a relatively simple matter, involving
principally flattening out and stretching the arc of the
sub-assembly 50, anchoring one end of it first and then anchoring
the other end. The plastic 60 may cover the ends 56 or may not, but
installation is the same in this instance in both forms.
Preferably, a plastic bearing block 68 lies below each tongue 67.
This bearing block 68 is preferably made from plastic that is
stiffer in consistency than the coating 60, and it serves as a
cushion preventing the tongues 67 from abrading or cutting through
the coating 60.
FIG. 6 also shows the anchoring of one border wire 58, a portion of
the plastic having been broken away from the wire ends 56 and 58 in
order to show the operation, though in this particular figure it is
not intended that they be actually uncovered. Thus, the wire 58 may
have an end portion 69 secured by butt weld to the wire end 56, or
both ends 56 and 69 may be loose, and a tongue 67 and block 68 may
embrace them both. It may be the same tongue 67 or two adjacent
tongues, as desired. In fact, they may be spcaed apart and separate
tongues used.
A modified Form of Attachment Employing Holes in the Frame Member
(FIGS. 8 and 9)
In FIGS. 8 and 9 a frame member 48a is provided with a series of
openings 70, and in each opening 70 a socket member 71 preferably
of a hard plastic material is inserted. The socket 71 may have an
outer flange 72 for locating it against the wall of the tubular
member 48a. It may have upwardly extending barbs 73, so that once
installed, it cannot be withdrawn except under great stripping
force, probably with destruction of the item itself, and it may
also have some down turned interior barbs 74 inside its tubular
opening 75. In this instance ends 76 of the wires 55 are bent at
substantially right angles to the plane of the seat 50; this
bending may be by a smooth curvature instead of a sharp angle, of
course. The wire ends 76 are installed in the chair frame by
inserting each end 76 into one of the socket openings 75, pushing
them down far enough so that they pass by the barbs 74 and,
preferably, so that they lie substantially flush against the flange
72. Then, the barbs 74 prevent retraction of these wire ends 76 and
hold them quite satisfactorily.
FIG. 8 also shows a border wire 77 that is not straight but is
sinuous; however, the border wire 77, while meeting the wire 55
along an arc 78 instead of a mere tangency, has much less amplitude
and is non-sagging to clothing while imparting a pleasing
curvaceous appearance to the front edge. Its end is locked in place
in the same way as the ends 76. It is more able to stretch itself
than a straight border wire.
FIG. 8 also shows a sinuous wire 79 of a different length and shape
from the other wires 55. The function of the wire 79 is to
introduce a member with different vibration characteristics from
the other wires 55. The effect of this is to provide
bounce-dampening, a feature usually found necessary in
transportation seating. The wires 55, characteristically having one
vibration frequency, are attached to the wire 79 which has a
different vibration frequency. This fact causes the structure to
have its bounce characteristics to be strongly modified if not
totally eliminated.
Installation of an Assembly 50 in a Wood Frame (FIG. 10)
FIG. 10 is a small sectional view illustrating the installation of
the assembly 50 to a wood frame member 80 by one feasible means. In
this instance, there is a deep slot 81 in the wood member 80, which
may be rectangular or round, since external shape makes no real
difference in this installation. The slot 81 is deep enough for
locating each of the wire ends 56 substantially as shown in FIG. 6.
Then a dowel or pin 82 of plastic or wood is inserted transversely
across each wire end 56 through an opening 83. Once again, the
chair is easily assembled by having the assembly 50 stretched out,
one end 56 of each wire 55 being located in the slot 81 and the
dowels 82 put in one by one.
A modified Form of Securement (FIGS. 11 and 12)
In FIGS. 11 and 12 a U-shaped channel chair frame member 85 is
shown. This member 85 may be either the chair frame or an
attachment to a tubular frame, if desired, and in the latter case
would fit over it and be welded or bolted or otherwise secured to
it. The channel member 85 has tongues 86 bent out from openings 87,
and they act to receive the wire 55 in substantially the same way
as did the tongues 67 in FIG. 6. While the wire ends 56 may be
installed in the tongues 86, the wires 55 etc. may be held not at
their actual ends 56 but one or more cycles parallel to the end, as
in FIG. 11 where wire portions 88 are held by the tongues 86.
By way of illustrating the variations possible in this invention,
the plastic 60 is used to make a substantially continuous edge rim
89, by having the wire ends 56 extend close to the adjacent wire,
so that they can be bridged over at this point and make a
continuous plastic rim. The front border wire 58 may have its end
69 welded to a wire end 56.
Another Modified Form of Installation (FIGS. 13 and 14)
In FIGS. 13 and 14 an assembly 90 (generally like the assembly 50)
is shown, and a chair frame 91 may have slots 92, which extend
circumferentially and are longer circumferentially than they are
wide. The spring ends 93 of the assembly 90 may be bent and hooked.
These hook portions 92 are installed into the interior of the
tubular member 91 through the slots 92, and then a dowel rod 94 or
other member is installed along the complete length of the frame
member 91 to hold the hook portion 93, and thereby the assembly 90,
in place. The dowel rod 94 may have some flexibility, and may be
plastic, especially for installation in a somewhat curved frame
91.
Another Installation Using a Flat Frame (FIGS. 15 and 16)
In FIGS. 15 and 16 a flat frame 95 is used having a series of
projections 96 which may be elliptical or oblong with arcuate ends
and about which the wires 55, 55a, etc. may nest adjacent their
ends 56. After the nesting has been done, an angle-shaped locking
member 97 may be placed over them and held in place by a series of
screws 98, as shown in FIG. 16. The projections 96 may be dimples,
as shown, with screw-receiving openings 99.
In this form of the invention, it will be seen that the wires 55a
and 55b are of different wire gauges; this is quite possible in the
invention, for the wires 55 need not be of uniform gauge
throughout. Lighter wires can be used at the ends and heavier wires
used in the center portions of the assembly 50, and this if often
desirable. An additional feature of varying the wire gauges is that
it helps to dampen vibrations, that is when wires of dissimilar
gauges are attached to each other, the rebound or oscillation rates
are dissimilar, and thus they act to dampen each other. other
advantages are obtained, such as stiffness where stiffness is
desired and flexibility where that is desired.
Another Form of Installation (FIGS. 17 and 18)
In FIG. 18 a frame member 100 is shown having a continuous
lengthwise-extending slot 101, through which the ends 57 of the
wires 55 may be installed. Inside each of the members 100 is a
segmented arcuate member 102 having a series of slots 103 with
tongues 104 between them. Each of the wire ends 57 is inserted
through a slot 103 and is prevented from retraction by the tongue
104. In this instance, the wire ends 57 may be inserted into the
slot 103 and tongue 104 before the member 102 is installed, or the
member 102 may be in place before the wire ends 57 are
installed.
Other means of installation may be used, including spot welding the
wire ends 56 and 57 to the chair frame or to a sub-assembly
therefor.
A method for Making the Assembly 50 (FIGS. 19 and 20)
FIGS. 19 and 20 illustrate some apparatus for and some aspects of a
method for making the assembly 50. In this case, a tool 110 has two
L-shaped handle members 111 and 112 joined together by a pivot pin
113. Each one of the handles 111, 112 has a series of serrations
114 for seating a ring 115 that may be used to hold the handles
111, 112 in a desired position. At one end of each of the members
111, 112 is provided a bracket member 116 very much like the member
102 just discussed. Each member 116 has tongues 117 and slots 118
along its extremity. The tool 110 may be strengthened by diagonal
members 119 which keep it rigid, so that the two bracket members
116 are parallel and straight.
Each wire 55 is hooked at or near its ends onto the two bracket
members 116 and spans between them, and the tongues 117 and slots
118 are so spaced that the wires 55 are automatically aligned to
lie tangent to each other. They are preferably installed so that
they are somewhat flattened from their natural shape in order to
get the tension that will hold them to these bracket members 116.
When the wires 55 have been individually installed, the whole may
be dipped as shown in FIG. 19. The tool 110 may spread the ends 116
apart, so that the wires 55 are arched, as shown, either wider or
narrower than their natural arc, but usually wider. The ends 56 of
the wires 55 need not be dipped, as shown here or the whole may be
entirely dipped, with later some parts being bare where they touch
the tool 110. The tool 110 itself may be coated to repel plastic in
such a way that it will not be coated even if immersed, or, as
shown in FIG. 19, it may be held so that no part of it gets
immersed. Immersion coats the wires with plastic 60, and this
plastic, upon curing, thereby forms the assembly 50.
This is, of course, only an example of many forms of such tools or
other mechanical aids that may be used in making the sub-assembly
50. It is possible to make the sub-assembly with the aid of more
sophisticated machinery so that the operation can be automated.
After dipping and cure, the assembly 50 is removed from the tool
110 and may be stored as a cylindrical unit. Several assemblies 50
may be nested within each other, if desired.
A method of Installation of the Sub-Assembly 50 on a Chair Frame
(FIG. 21)
FIG. 21 shows that the same tool 110 which was used in making the
assembly 50 may also be used to install the assembly 50 on a chair
frame by stretching out and flattening the assembly 50 and by
hooking its wire ends 56 and 57 over suitable securing devices such
as the devices 65 shown in FIGS. 1 and 6. Once the wire ends 56 and
57 have been caught and held by the members 65, the assembly 50 may
be released from the tool 110 and the tool withdrawn.
Application of the Invention to Stackable Chairs (FIGS. 22 and
23)
Compactlystackable chairs such as those shown in my U. S. Pat. No.
Re. 26,071 may be used in conjunction with the present invention to
provide a more resilient seat than the hard seat heretofore used
with those chairs. As shown in FIG. 22 a chair frame 120 may have
curved lines, as discussed in FIG. 5 by virtue of this invention,
and the seats 121 and backs 122 are easily made so that they nest
within each other when the chair frames 120 are stacked, so long as
the chairs themselves are of stackable structure. Any type of
stackable structure may be used with these seats and backs, and
since they are quite thin, a compactly stackable structure becomes
feasible with the stacking height of a set of chairs being
determined basically by the thickness of the chair frames 120.
These chair frames, if desired, may be made quite thin.
FIG. 23 shows how the backs 122 stack one within the other. It will
be seen that the chord across the arc of the one chair intercepts
the arc of the next adjacent chair. The same basic configuration
also applies to the seats.
A fore-and-Aft Chair Seat Arrangement (FIGS. 24 and 25)
FIG. 24 shows a chair 130 incorporating a seat assembly 131 and a
back assembly 132. The back assembly 132 is substantially like the
back assembly 50A, with two major exceptions. First, the frame
members 133 and 134 to which the back assembly 162 is secured
extend horizontally rather than vertically. Second, the assembly
132 bows forwardly as seen from a side view and rearwardly as seen
from a top view curving along a vertical arc. By virtue of the
stretchability of the back assembly 132, the lower frame member 134
supporting the back 132 may be straight while the upper member 133
is curved. (See FIG. 26 which has an identical member 133.) There
are no border wires, so that the wires 55 are free at each side,
but since they are at the sides of the chair frame, they are
unlikely to catch on clothing. Furthermore, in this particular form
of the invention the plastic covered wires 55 are covered with
fabric 137, so that the wires are not truly exposed and do not
present that apparent hazard.
The seat member 131 is basically like the back member 132, but has
an important difference. The similarities are that the wires 55 are
free at each side, that the seat is covered with fabric 137 and
that the seat member 131 has its wire ends 140 and 141 secured to
transverse-extending chair frame members 135 and 134. The
difference is that a sharp bend 142 is provided, spaced from but
relatively near the end 141. This bend 142 functions (a) to give
the chair its fore-and-aft seating pattern, which obviously differs
from the side-to-side pattern of the chair shown in FIG. 1, (b) a
resiliency at the front which is extremely desirable, and (c) an
accentuated curve at the front end which makes the chair more
comfortable than it would be if this were absent.
Another Fore-and-Aft Seat Arrangement (FIGS. 26 to 28)
A chair 145 is shown in FIG. 26 having a seat assembly 146 and a
back assembly 132 like that of the chair 130. The difference
between the seat assembly 146 and the seat 131 is that the seat
assembly 146 has what is sometimes called a "fishmouth"
construction, with two sharp bends 147 and 148 adjacent a forward
edge 149. The rear end member 140 is the same as in the chair 130.
The fishmouth structure gives the seat 146 additional springiness
and comfort and it is considered desirable by some
manufacturers.
FIG. 28 shows how the wire ends 140 of the seat 146 or 131 and the
wire ends 136 of the back 132 can be secured to a single horizontal
frame member 134, with the aid of a securing strip 150, similar to
the strip 65, which receive both wire ends 140 and 136, with the
aid of a series of a pair of ears 151 and 152 secured to the frame
member 134, as by a screw or by welding. The wire ends are
installed thereby in a bracket 150 which is held by a single frame
member 134.
Some of the Many Patterns of Wires Possible in This Invention
(FIGS. 29 to 37)
A substantially infinite number of wire patterns are possible under
this invention. The one shown heretofore with the wire 55 is a very
good pattern, but it is not the only one that can be used. Patterns
can be used for their structural features, because of manufacturing
convenience, or because of design features. Some of these features
will appear from the selected forms shown, and in all of them it
will be seen that the wires, whether in parallel or alternate
patterns, touch each other at least once per cycle; the touching
may be flush to each other in the same plane or may be by an
overlap of planes with the units still having substantially the
same plane.
FIG. 29 shows a wire 211 with vinyl covering 212 and an adjacent
wire 213 with vinyl covering 212 also on it. The wires 211 and 213
are bent in the same pattern but are set to alternate, so that one
is rotated 180.degree. relative to the other; instead of each wire
211 being strictly parallel to its adjacent wire 213, the
sinuosities are reversed, and the alternating effect is obtained.
Alternation can give some interesting designs, such as the one
shown here. The length of the one cycle has been marked on the
drawing, and it will be seen that the cycle is rather long, partly
due to the alternation and partly due to the wire pattern itself.
Thus the wire 211, starting from the left-hand end, has a long
vertical portion 214, then a horizontal portion 215 succeeded by a
short vertical portion 216, then a horizontal portion 217
preferably the same length as the portion 215. The portion 217 is
followed by a portion 218, identical in length to the portion 216
and then leading to another portion 219, which is parallel to and
in line with the portion 215 and is again of the same length. The
portion 219 is followed by a portion 220 that is longer than the
portions 216 and 218, and equal in length to the portion 214,
therefore raising the wire 211 up to a new level. This is succeeded
by a horizontal portion 221 of the same length as the portions 215
and 219 and parallel to them but displaced from them. This in turn
is succeeded by a short portion 222, the same length as the portion
218 but starting from a different place so that the succeeding
portion 223 is not in line with the portions 215 and 219, though
parallel to them. Another portion 224 equal in length to the
portion 222 is followed by the portion 225 in line with and equal
in length to the portion 221, and this is followed in turn by a
portion 214a identical to the portion 214 and beginning a new
cycle.
The wire 213 adjacent to the wire 211 has the same pattern but is
reversed, so that the wires 211 and 213 touch at the portions 215
and 219. The wires 211 and 213 touch or come close to the other
wires to which they are adjacent to portions 221 and 225. These
touching portions in this instance extend for the whole width, and
the plastic coating 212 covers these portions as well as the
individual wires.
FIG. 30 shows a wire 230 having a sinuous shape and an adjacent
identical wire 231, both of them being covered by plastic 232. The
length of one cycle is in this instance much shorter. The wire 230
has a flaring portion that describes what are nearly two circles
233 and 234, with their radii displaced, and these near circles 233
and 234 are joined by a smooth connecting curve 235. Again, the
pattern is interesting, and the structural effects are
substantially the same as what has already been described.
FIG. 31 shows a wire 240 which is made in a sinuous pattern not
unlike the wire 55. The adjacent wires are overlapped, so that the
wire 240 lies over a wire 241 and beneath a wire 242, and the
plastic covering 243 joins all the wires. This pattern provides a
small opening 244 through the overlaps and a large opening 245.
This makes an interesting pattern, is another way of forming the
assembly, and shows that the wires do not have to abut and lie in
the identical plane.
FIG. 32 shows a wire 250 with an adjacent wire 251 and with plastic
covering 252. Another type of square-wave pattern is shown giving a
different pattern and again the length of cycle is shown.
FIG. 33 shows another form of pattern. In this case a wire 255
actually overlaps itself with a succession of circles so that no
one wire actually lies in a single plane, but there is, of course,
substantially a planar configuration. The successive wires abut
each other.
FIG. 34 shows another square-wave configuration with steps down and
up with wires 260 and 261 etc., and plastic coating 262.
FIGS. 35 and 36 show an angular configuration and two different
uses of the same wire 265 and coating 266. In FIG. 35 the adjacent
wires are reversed to make big spaces in between, while in FIG. 36
the successive wires 265 are parallel to make trapezoids that are
in each row alternately converted. The effects are different with
the same wires. In addition, an additional wire 267 is used in FIG.
36; this wire 267 is of a different shape and curve length and is
used for bounce-dampening, as is the wire 79 of FIG. 8.
FIG. 37 shows overlapped wire 270, 271 covered by a coating 272
which fastens the wires 270 and 271 together, with one wire 270
going under its adjacent wire 271, which in turn goes under its
adjacent wire 273, and so on.
These are only examples of what can be done. Countless other
patterns are possible.
Some Other Embodiments
FIG. 38 shows the lower portion of a chair 280 having an assembly
50 serving as a seat but inverted with respect to FIG. 1. While
generally not preferable, this structure is quite usable. Here
there is a simple trough shape.
FIG. 39 shows a stool 285 having a spring seat made by an assembly
50 installed with double curvature, a concave arc bent into an
upper or convex arc as seen from the side.
The thinness of the seats and backs of this invention is especially
important. Thus the thickness of the coated wire -- which is the
seat or back thickness -- should be between one two-hundreths and
one-fiftieth of the cylindrical arc length of the assembly 50,
i.e., of what is to be the span of the seat or back.
To those skilled in the art to which this invention relates, many
changes in construction and widely differing embodiments and
applications of the invention will suggest themselves without
departing from the spirit and scope of the invention. The
disclosures and the description herein are purely illustrative and
are not intended to be in any sense limiting.
* * * * *