U.S. patent application number 10/581464 was filed with the patent office on 2007-11-22 for molded wood flake article with integral flexible spring member.
This patent application is currently assigned to J. R. Britton & Associates, Inc.. Invention is credited to Jeff R. Britton, Samuel S. Conte.
Application Number | 20070267912 10/581464 |
Document ID | / |
Family ID | 34713758 |
Filed Date | 2007-11-22 |
United States Patent
Application |
20070267912 |
Kind Code |
A1 |
Britton; Jeff R. ; et
al. |
November 22, 2007 |
Molded Wood Flake Article with Integral Flexible Spring Member
Abstract
A molded wood flake support is fabricated to include at least
one flexible spring member which is narrower then the width of the
molded wood flake support and integrally formed therewith or
secured thereto, wherein the flexible spring member can flex
independently from the molded wood flake support.
Inventors: |
Britton; Jeff R.; (Leo,
IN) ; Conte; Samuel S.; (Fort Wayne, IN) |
Correspondence
Address: |
PRICE HENEVELD COOPER DEWITT & LITTON, LLP
695 KENMOOR, S.E.
P O BOX 2567
GRAND RAPIDS
MI
49501
US
|
Assignee: |
J. R. Britton & Associates,
Inc.
16120 Tother Road
Leo
IN
46765
|
Family ID: |
34713758 |
Appl. No.: |
10/581464 |
Filed: |
October 22, 2004 |
PCT Filed: |
October 22, 2004 |
PCT NO: |
PCT/US04/35063 |
371 Date: |
April 18, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60585323 |
Jul 2, 2004 |
|
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60526783 |
Dec 2, 2003 |
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Current U.S.
Class: |
297/452.49 ;
297/452.1 |
Current CPC
Class: |
A47C 7/024 20130101;
A47C 7/16 20130101; A47C 7/46 20130101; A47C 7/405 20130101; A47C
7/445 20130101 |
Class at
Publication: |
297/452.49 ;
297/452.1 |
International
Class: |
A47C 7/16 20060101
A47C007/16; A47C 7/18 20060101 A47C007/18 |
Claims
1-99. (canceled)
100. A support comprising: a support member having a width; and at
least one molded wood flake flexible spring which is narrower than
said width of said support member, said flexible spring including a
free end and a joined end, said joined end being integrally formed
with said support member, wherein said flexible spring can flex
independently from said support member.
101. The support as defined in claim 100 wherein said support
member and flexible spring are integrally fabricated substantially
of wood flakes.
102. The support as defined in claim 100 wherein said support
member includes a plurality of spaced-apart molded wood flake
flexible springs.
103. The support as defined in claim 100 wherein said at least one
molded wood flake flexible spring is defined by a U-shaped channel
formed in said support member.
104. The support as defined in claim 100 wherein said support
member comprises a seat and said at least one molded wood flake
flexible spring is disposed within said seat.
105. The support as defined in claim 100 wherein said support
member includes at least one channel disposed therein, said at
least one channel defining said at least one molded wood flake
flexible spring and said at least one channel is integrally molded
within said support member.
106. A molded wood flake support for a seating article which at
least partially supports a user seated thereon, said molded wood
flake support comprising: a base section molded of binder coated
wood flakes, said base section including a frame section having a
main portion and an integral seating section formed at an angle to
said main portion of said frame section; and said seating section
including at least one molded wood flake flexible spring including
a free end and a joined end integrally formed with said frame
section, wherein said flexible spring can flex independently from
said main portion of said frame section.
107. The molded wood flake support as defined in claim 106 wherein
said support is fabricated substantially of wood flakes.
108. The molded wood flake support as defined in claim 107 wherein
said seating section includes a plurality of spaced-apart molded
wood flake springs.
109. The molded wood flake support as defined in claim 108 wherein
said wood flake springs are defined by a channel separating
adjacent springs.
110. The molded wood flake support as defined in claim 109 wherein
said at least one channel is molded into said support and
terminates in said frame section and a circular aperture is formed
through said frame section at the junction of said channel and
frame section.
111. The molded wood flake support as defined in claim 106 wherein
said at least one molded wood flake flexible spring comprises a
plurality of spaced-apart molded wood flake flexible springs.
112. The molded wood flake support as defined in claim 106 further
including a back molded of binder coated wood flakes connected with
said base section, wherein said back includes at least one molded
wood flake flexible spring.
113. The molded wood flake support as defined in claim 112 wherein
said back includes a seat facing side and said at least one molded
wood flake flexible spring extends outwardly from said seat facing
side of said back.
114. A molded wood flake support according to claim 106 wherein
said support includes at least one channel disposed therein, said
at least one channel defining said at least one molded wood flake
flexible spring and said at least one channel is integrally molded
within said support.
115. The molded wood flake support as defined in claim 110 further
including an elastomeric mesh coupled to said springs.
116. A molded wood flake article for a seating member said molded
wood flake support comprising: a support section molded of binder
coated wood flakes including a frame section having a main portion
and a plurality of spaced-apart molded wood flake flexible springs
including free ends and joined ends integrally formed with said
frame section, wherein said flexible springs can flex independently
from said main portion; a rigid panel mounted in spaced
relationship to said support section; and a foam pad extending
between said rigid panel and said support section and coupled to
said molded wood flake flexible springs for supplementing the
spring resistance of said flexible molded wood flake springs.
117. The molded wood flake support as defined in claim 116
including a plurality of spaced-apart foam pads extending between
said rigid panel and said support section.
118. The molded wood flake support as defined in claim 116 wherein
said wood flake springs are defined by a channel separating
adjacent springs.
119. The molded wood flake support as defined in claim 118 wherein
said at least one channel is molded into said support and
terminates in said frame section and a circular aperture is formed
through said frame section at the junction of said channel and
frame section.
120. The molded wood flake support as defined in claim 107 wherein
said flexible spring includes a longitudinal indentation extending
into said frame section to stiffen said spring.
Description
BACKGROUND OF THE INVENTION
[0001] Wood flake molding, also referred to as wood strand molding,
is a technique invented by wood scientists at Michigan
Technological University during the latter part of the 1970s for
molding three-dimensionally configured objects out of binder coated
wood flakes having an average length from about 11/4 to about 6
inches, preferably from about 2 to about 3 inches; an average
thickness of about 0.005 to about 0.075 inches, preferably from
about 0.015 to about 0.030 inches; and an average width of 3 inches
or less, most typically 0.25 to 1.0 inches, and never greater than
the average length of the flakes. These flakes are sometimes
referred to in the art as "wood strands." This technology is not to
be confused with oriented strand board technology (see e.g., U.S.
Pat. No. 3,164,511 to Elmendorf) wherein binder coated strands of
wood are pressed into planar objects. In wood flake or wood strand
molding, the flakes are molded into three-dimensional, i.e.,
non-planar, configurations.
[0002] In wood flake molding, flakes of wood having the dimensions
outlined above are coated with methylene diisocyanate (MDI) or
similar binder and deposited onto a metal tray having one open
side, in a loosely felted mat, to a thickness eight or nine times
the desired thickness of the final part. The loosely felted mat is
then covered with another metal tray, and the covered metal tray is
used to carry the mat to a mold. (The terms "mold" and "die", as
well as "mold die", are sometimes used interchangeably herein,
reflecting the fact that "dies" are usually associated with
stamping, and "molds" are associated with plastic molding, and
molding of wood strands does not fit into either category.) The top
metal tray is removed, and the bottom metal tray is then slid out
from underneath the mat, to leave the loosely felted mat in
position on the bottom half of the mold. The top half of the mold
is then used to press the mat into the bottom half of the mold at a
pressure of approximately 600 psi, and at an elevated temperature,
to "set" (polymerize) the MDI binder and to compress and adhere the
compressed wood flakes into a final three-dimensional molded part.
The excess perimeter of the loosely felted mat, that is, the
portion extending beyond the mold cavity perimeter, is pinched off
where the part defining the perimeter of the upper mold engages the
part defining the perimeter of the lower mold cavity. This is
sometimes referred to as a pinch trim edge.
[0003] U.S. Pat. Nos. 4,440,708 and 4,469,216 disclose this
technology. The drawings in U.S. Pat. No. 4,469,216 best illustrate
the manner in which the wood flakes are deposited to form a loosely
felted mat, though the metal trays are not shown. By loosely
felted, it is meant that the wood flakes are simply lying one on
top of the other in overlapping and interleaving fashion, without
being bound together in any way. The binder coating is quite dry to
the touch, such that there is no stickiness or adherence which hold
them together in the loosely felted mat. The drawings of U.S. Pat.
No. 4,440,708 best illustrate the manner in which a loosely felted
mat is compressed by the mold halves into a three-dimensionally
configured article (see FIGS. 2-6, for example).
[0004] The above described process is a different molding process
as compared to a molding process one typically thinks of, in which
some type of molten, semi-molten or other liquid material flows
into and around mold parts. Wood flakes are not molten, are not
contained in any type of molten or liquid carrier, and do not
"flow" in any ordinary sense of the word. Hence, those of ordinary
skill in the art do not equate wood flake or wood strand molding
with conventional molding techniques.
[0005] It has been discovered that wood flake molded parts have a
very well defined spring constant. Sections of molded wood flake
articles having a thickness of 1/2, 9/16, and 5/8 inches and a
width of 2 inches and an effective length of 16 inches were mounted
to define a cantilevered spring and were tested. It was discovered
that the spring constant for the respective thickness of 1/2 inch
was 10 pounds per inch deflection; 9/16 inch was 11 pounds per inch
deflection; and 5/8 inch thick was 14 pounds per inch deflection.
It was further discovered that the molded wood flake spring so
formed returned to its original position within two minutes of a
load being removed and displays only a 5 percent to 8 percent
hysteresis over time. In view of the fact that the molded wood
flakes can be formed in any desired three-dimensional
configuration, this discovery allows the material to be used for
deflectable weight supporting articles, such as in the seating
environment. A clear benefit of using such spring material as
opposed to typical coil springs or sinuous wire springs is that
they are not subject to rust nor do they require the intense labor
necessary when manufacturing a chair or other seating object
utilizing conventional springs. Further, the feel of the seat
utilizing such springs is improved inasmuch as the springs do not
require preloading, as with typical sinuous or coil springs. Thus,
the use of molded wood flake springs will revolutionize the
manufacture of supports which, in past years, required the use of
sinuous or coil springs.
SUMMARY OF THE INVENTION
[0006] In the present invention a molded wood flake support article
includes at least one flexible spring. The support may include a
plurality of integral spaced-apart linearly extending springs with
second ends opposite said first ends that are free to flex, wherein
the support is coupled to a frame member. In one embodiment, a
plurality of spaced-apart linearly extending spring members are
integrally formed from a connecting end piece. The end piece can,
in one embodiment, be a curved edge of a seat frame. In one
embodiment, an elastomeric mesh is coupled over free ends of the
spring members to loosely interconnect the ends of said springs. In
yet another embodiment, a seat is formed employing a plurality of
spaced-apart linearly extending spring members integrally formed
with one end of the seat base having sides coupled thereto, and an
elastomeric web extends between the sides underlying said spring
members to limit their deflection. In one embodiment also, the
elastomeric web can be vertically and horizontally adjusted on the
base with respect to the spring members to change the deflection
characteristics of said spring members and, thus, the feel of the
seat so-formed.
[0007] These and other features, advantages and objects of the
present invention will be further understood and appreciated by
those skilled in the art by reference to the following
specification, claims and appended drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a perspective view of a chair with a plurality of
flexible spring members disposed on a back thereof according to one
embodiment of the present invention;
[0009] FIG. 2 is a fragmentary front view, partly in cross section,
of a molding apparatus with a wood flake mat positioned
therebetween before compression;
[0010] FIG. 3 is a view of the molding apparatus of FIG. 2, shown
during compression;
[0011] FIG. 4 is a perspective view of the chair back of FIG.
1;
[0012] FIG. 5 is a perspective view of a chair seat with a
plurality of flexible spring members according to one embodiment of
the present invention;
[0013] FIG. 6 is a perspective view of a chair body according to
another embodiment;
[0014] FIG. 7 is a perspective view of a chair according to yet
another embodiment;
[0015] FIG. 8 is a left side elevational view of the chair of FIG.
7, illustrating the deflection of the chair back and flexible
spring member;
[0016] FIG. 9 is a perspective view of the chair back of FIG. 7
including a foam lumbar support and foam covering;
[0017] FIG. 10 is a perspective view of a chair according to
another embodiment of the present invention;
[0018] FIG. 11 is a left side elevational view of the chair of FIG.
10;
[0019] FIG. 12 is a perspective view of a chair according to yet
another embodiment of the present invention;
[0020] FIG. 13 is a perspective view of a sofa, partly in phantom
form, wherein the sofa back includes a plurality of flexible spring
members according to another embodiment of the present
invention;
[0021] FIG. 14 is a left side elevational view of the sofa back of
FIG. 13;
[0022] FIG. 15 is an exploded perspective view of a chair body of
an alternative embodiment of the present invention;
[0023] FIG. 16 is a perspective view of the chair body shown in
FIG. 15;
[0024] FIG. 17 is a perspective view of an alternative embodiment
of the chair body shown in FIGS. 15 and 16;
[0025] FIG. 18 is an exploded perspective view of another
embodiment of the chair body of the type shown in FIGS. 15 and
16;
[0026] FIG. 19 is a perspective view of yet another embodiment of
the chair body shown in FIGS. 15 and 16;
[0027] FIG. 20 is a cross-sectional view of the chair body of FIG.
19, taken along section line XX-XX in FIG. 19;
[0028] FIG. 21 is an exploded perspective view of yet another
embodiment of the chair body shown in FIGS. 15 and 16;
[0029] FIG. 22 is a left side elevational assembled view of the
chair body shown in FIG. 21;
[0030] FIG. 23 is a pictorial view of an adjustable structure for
the support web shown in the chair body of FIGS. 21 and 22;
[0031] FIG. 24 is a perspective view of an alternative embodiment
of a chair body; and
[0032] FIG. 25 is an enlarged cross-sectional view of one of the
spring members of the chair body of FIG. 24, taken along section
lines XXV-XXV of FIG. 24.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] For purposes of description herein, the terms "upper,"
"lower," "right," "left," "rear," "front," "vertical,"
"horizontal," and derivatives thereof shall relate to the invention
as orientated in FIG. 1. However, it is to be understood that the
invention may assume various alternative orientations, except where
expressly specified to the contrary. It is also to be understood
that the specific devices and processes illustrated in the attached
drawings, and described in the following specification are simply
exemplary embodiments of the inventive concepts defined in the
appended claims. Hence, specific dimensions and other physical
characteristics relating to the embodiments disclosed herein are
not to be considered as limiting, unless the claims expressly state
otherwise.
[0034] In a preferred embodiment of the present invention, a molded
wood flake article (FIG. 1), such as the back 12 of a chair 10, is
fabricated to include a plurality of spaced-apart flexible spring
members 14, wherein the flexible spring members can flex
independently. In the preferred embodiment, the flexible spring
members 14 are integrally molded into support 12 during the
fabrication process thereof and integrally extend from a base
section 16 of the seat back 12 in a comb-like configuration, as
seen in FIG. 4.
Process Details:
[0035] As best illustrated by FIG. 2, in wood flake or wood strand
molding the flakes are molded into three-dimensional, non-planar,
configurations by utilizing a mold 20 which forms wood flakes 22
into a molded wood flake part, such as part 12. Mold 20 includes a
top mold die 26 and a bottom mold die 28. The top mold die 26
includes a surface 21 and at least one extension 23 extending from
the surface 21 for forming slots 18 (FIG. 1) which define the
perimeter of flexible spring members 14. The bottom mold die 28
includes a surface 25 having at least one extension receiving
cavity 27. The surface 21 of the top mold die 26 and the surface 25
of the bottom mold die 28 define a part forming cavity 30
therebetween which forms part 12 into a desired shape, while
extension 23 is configured to extend through molded wood flake part
12 and into cavity 27 to form slots 18, thereby defining at least
one flexible spring member 14 which can flex independently from the
molded wood flake support or part 12 as illustrated in FIG. 1. Of
course, slots 18 may be fabricated by other methods including
sawing, cutting, machining and the like.
[0036] As illustrated by FIGS. 2-3, the molded wood flake part 12
is made by positioning a loosely felted mat 32 of wood flakes 22 on
the bottom mold die 28. The top mold die 26 and the bottom mold die
28 are then brought together or closed, wherein heat and pressure
are applied to felted mat 32. Felted mat 32 is thereby compressed
and cured into the molded wood flake part 12 having flexible spring
member 14 formed therein. In the preferred embodiment, this is
accomplished by having extension 23 pass, cut or push through mat
32, forcing wood flakes 22 down into extension receiving cavity 27
to form slots 18. Although only one extension 23 is shown in the
illustrated example, a plurality of spaced-apart extensions and
cavities are typically used to form a plurality of spaced-apart
flexible spring members 14 as illustrated in FIG. 1.
[0037] The molded wood flake part 12 may include additional
features such as "T" nut fastener holes 34 (FIG. 4). For example as
FIGS. 2-3 illustrate, an extension 36 may be used to make hole 34
and is received within cavity 33. The resulting hole 34 provides a
uniform appearance from the surface of the molded wood flake part
and facilitates the insertion of a T-nut (not shown) from either
surface with its mounting flange and associated bar resting on a
surface of the molded wood flake part which has been formed, and
with its threaded sleeve projecting inwardly into the hole 34. The
width of the hole 34 is sufficiently great throughout its length
that it will accommodate a sleeve of a T-nut or other item to be
inserted into the hole 34, without interference.
[0038] As seen in FIG. 3, the top surface 35 of the molded wood
flake part 12 is adjacent the surface 21 of the top mold die 26 and
the bottom surface 37 of the molded wood flake part 12 is adjacent
the surface 25 of the bottom mold die 28 after the wood flakes 22
have been consolidated, compressed and cured into the molded wood
flake part 12. The molded wood flake parts 12 made in this manner
will preferably have a nominal thickness T of from about 3/8 inch
to about 5/8 inch. Felted mat 32, however, will be compressed to
varying thicknesses by mold 20, due to unavoidable inconsistencies
of mat 32, such as spring back of the mat, over-compression, or the
like. Therefore, the bottom surface 37 of molded wood flake part 12
will be located within a zone of variation in part thickness. The
zone of variation in part thickness is the area in which the bottom
surface 37 of the molded wood flake part 12 could be located,
depending on the thickness of the molded wood flake part 12,
compared to a stationary position for the top surface 35 of the
molded wood flake part 12.
[0039] The wood flakes 22 used in creating the molded wood flake
part 12 can be prepared from various species of suitable hardwoods
and softwoods. Representative examples of suitable woods include
aspen, maple, oak, elm, balsam fir, pine, cedar, spruce, locust,
beech, birch and mixtures thereof, although aspen is preferred.
[0040] Suitable wood flakes 22 can be prepared by various
techniques. Pulpwood grade logs, or so-called round wood, are
converted into wood flakes 22 in one operation with a conventional
roundwood flaker. Logging residue or the total tree is first cut
into fingerlings having an average length from about 11/4 to about
6 inches, preferably from about 2 to about 3.5 inches with a
device, such as the helical comminuting shear disclosed in U.S.
Pat. No. 4,053,004, and the fingerlings are subsequently flaked in
a conventional ring-type flaker. Roundwood wood flakes generally
are higher quality and produce stronger parts because the lengths
and thickness can be more accurately controlled. Also, roundwood
wood flakes tend to be somewhat flatter, which facilitates more
efficient blending and the logs can be debarked prior to flaking
which reduces the amount of less desirable fines produced during
flaking and handling. Acceptable wood flakes can be prepared by
ring flaking fingerlings. This technique is more readily adaptable
to accept wood in poorer form, thereby permitting more complete
utilization of certain types of residue and surplus woods.
[0041] Irrespective of the particular technique employed for
preparing the wood flakes 22, the size distribution of the wood
flakes 22 is quite important, particularly the length and
thickness. The wood flakes should have an average length from about
11/4 to about 6 inches, preferably from about 2 to about 31/2
inches; an average thickness of about 0.005 to about 0.075 inches,
preferably from about 0.015 to about 0.030 inches and more
preferably about 0.0020 inch; and an average width of 3 inches or
less, most typically 0.25 to 1.0 inches, and less than the average
length of the flakes. In any given batch, some of the wood flakes
22 can be shorter than 11/4 inch, and some can be longer than 6
inches, so long as the overall average length is within the above
range. The same is true for the thickness.
[0042] The presence of major quantities of wood flakes 22 having a
length shorter than about 11/4 inch tends to cause the felted mat
32 to pull apart during the molding step. The presence of some
fines in the felted mat 32 produces a smoother surface and, thus,
may be desirable for some applications so long as the majority of
the wood flakes, preferably at least 75 percent, is longer than
11/8 inch and the overall average length is at least 11/4 inch.
[0043] Substantial quantities of wood flakes 22 having a thickness
of less than about 0.005 inches should be avoided, because
excessive amounts of binder are required to obtain adequate
bonding. On the other hand, wood flakes 22 having a thickness
greater than about 0.075 inch are relatively stiff and tend to
overlie each other at some incline when formed into the felted mat
32. Consequently, excessively high mold pressures are required to
compress the wood flakes 22 into the desired intimate contact with
each other. For wood flakes 22 having a thickness falling within
the above range, thinner ones produce a smoother surface while
thick ones require less binder. These two factors are balanced
against each other for selecting the best average thickness for any
particular application.
[0044] The width of the wood flakes 22 is less important. The wood
flakes 22 should be wide enough to ensure that they lie
substantially flat when felted during mat formation. The average
width generally should be about 3 inches or less and no greater
than the average length. For best results, the majority of the wood
flakes 22 should have a width of from about 0.25 to about 1.0
inches.
[0045] The blade setting on a flaker can primarily control the
thickness of the wood flakes 22. The length and width of the wood
flakes 22 are also controlled to a large degree by the flaking
operation. For example, when the wood flakes 22 are being prepared
by ring flaking fingerlings, the length of the fingerlings
generally sets the maximum lengths. Other factors, such as the
moisture content of the wood and the amount of bark on the wood
affect the amount of fines produced during flaking. Dry wood is
more brittle and tends to produce more fines. Bark has a tendency
to more readily break down into fines during flaking and subsequent
handling than wood.
[0046] While the flake size can be controlled to a large degree
during the flaking operation as described above, it usually is
necessary to use a screening process in order to remove undesired
particles, both undersized and oversized, and thereby ensure the
average length, thickness and width of the wood flakes 22 are
within the desired ranges. When roundwood flaking is used, both
screen and air classification usually are required to adequately
remove both the undersize and oversize particles, whereas
fingerling wood flakes usually can be properly sized with only
screen classification.
[0047] Wood flakes from some green wood can contain up to 90
percent moisture. The moisture content of the mat must be
substantially less for molding as discussed below. Also, wet wood
flakes tend to stick together and complicate classification and
handling prior to blending. Accordingly, the wood flakes 22 are
preferably dried prior to classification in a conventional type
drier, such as a tunnel drier, to the moisture content desired for
the blending step. The moisture content to which the wood flakes 22
are dried usually is in the order of about 6 weight percent or
less, preferably from about 2 to about 5 weight percent, based on
the dry weight of the wood flakes 22. If desired, the wood flakes
22 can be dried to a moisture content in the order of 10 to 25
weight percent prior to classification and then dried to the
desired moisture content for blending after classification. This
two-step drying may reduce the overall energy requirements for
drying wood flakes prepared from green woods in a manner producing
substantial quantities of particles which must be removed during
classification and, thus, need not be as thoroughly dried.
[0048] To coat the wood flakes 22 prior to being placed as a felted
mat 32 within the cavity 30 of mold 20, a known amount of the
dried, classified wood flakes 22 is introduced into a conventional
blender, such as a paddle-type batch blender, wherein predetermined
amounts of a resinous particle binder, and optionally a wax and
other additives, is applied to the wood flakes 22 as they are
tumbled or agitated in the blender. As such, the article fabricated
from wood flakes 22 is substantially rather than entirely comprised
of wood flakes, as other additives as described above are added to
create mat 32. Of course, other base materials may also be added to
the wood flakes to form a mat 32 comprising a blend of wood flakes
22 and other suitable materials. Suitable binders include those
used in the manufacture of particle board and similar pressed
fibrous products and, thus, are referred to herein as "resinous
particle board binders." Representative examples of suitable
binders include thermosetting resins such as phenolformaldehyde,
resorcinol-formaldehyde, melamine-formaldehyde, urea-formaldehyde,
urea-furfuryl and condensed furfuryl alcohol resins, and organic
polyisocyantes, either alone or combined with urea- or
melamine-formaldehyde resins.
[0049] Particularly suitable polyisocyanates are those containing
at least two active isocyanate groups per molecule, including
diphenylmethane diisocyanates, m- and p-phenylene diisocyanates,
chlorophenylene diisocyanates, toluene di- and triisocyanates,
triphenylmethene triisocyanates,
diphenylether-2,4,4'-triisoccyanate and polyphenylpolyisocyanates,
particularly diphenylmethane-4,4'-diisocyanate. So-called MDI is
particularly preferred.
[0050] The amount of binder added to the wood flakes 22 during the
blending step depends primarily upon the specific binder used,
size, moisture content, type of the wood flakes and the desired
characteristics of the part being formed. Generally, the amount of
binder added to the wood flakes 22 is from about 31/2 to about 15
weight percent, preferably from about 4 to about 10 weight percent,
and most preferably about 5 percent. When a polyisocyanate is used
alone or in combination with a urea-formaldehyde resin, the amounts
can be more toward the lower ends of these ranges.
[0051] The binder can be admixed with the wood flakes 22 in either
dry or liquid form. To maximize coverage of the wood flakes 22, the
binder preferably is applied by spraying droplets of the binder in
liquid form onto the wood flakes 22 as they are being tumbled or
agitated in the blender. When polyisocyantes are used, a
conventional mold release agent preferably is applied to the die or
to the surface of the felted mat prior to pressing. To improve
water resistance of the part, a conventional liquid wax emulsion is
also sprayed on the wood flakes 22 during the blinding step. The
amount of wax added generally is about 0.5 to about 2 weight
percent, as solids, based on the dry weight of the wood flakes 22.
Other additives, such as one of the following: a coloring agent,
fire retardant, insecticide, fungicide, mixtures thereof and the
like may also be added to the wood flakes 22 during the blending
step. The binder, wax and other additives, can be added separately
in any sequence or in combined form.
[0052] The moistened mixture of binder, wax and wood flakes 22 or
"furnish" from the blending step is formed into a loosely-felted,
layered mat 32, which is placed within the cavity 30 prior to the
molding and curing of the felted mat 32 into molded wood flake part
12. The moisture content of the wood flakes 22 should be controlled
within certain limits so as to obtain adequate coating by the
binder during the blending step and to enhance binder curing and
deformation of the wood flakes 22 during molding.
[0053] The presence of moisture in the wood flakes 22 facilitates
their bending to make intimate contact with each other and enhances
uniform heat transfer throughout the mat during the molding step,
thereby ensuring uniform curing. However, excessive amounts of
water tend to degrade some binders, particularly urea-formaldehyde
resins, and generate steam which can cause blisters. On the other
hand, if the wood flakes 22 are too dry, they tend to absorb
excessive amounts of the binder, leaving an insufficient amount on
the surface to obtain good bonding and the surfaces tend to cause
hardening which inhibits the desired chemical reaction between the
binder and cellulose in the wood. This latter condition is
particularly true for polyisocyanate binders.
[0054] Generally, the moisture content of the furnish after
completion of blending, including the original moisture content of
the wood flakes 22 and the moisture added during blending with the
binder, wax and other additives, should be about 5 to about 25
weight percent, preferably about 8 to about 12 weight percent.
Generally, higher moisture contents within these ranges can be used
for polyisocyanate binders because they do not produce condensation
products upon reacting with cellulose in the wood.
[0055] The furnish is formed into the generally flat,
loosely-felted, mat 32, preferably as multiple layers. A
conventional dispensing system, similar to those disclosed in U.S.
Pat. Nos. 3,391,223 and 3,824,058, and 4,469,216 can be used to
form the felted mat 32. Generally, such a dispensing system
includes trays, each having one open side, carried on an endless
belt or conveyor and one or more (e.g., three) hoppers spaced above
and along the belt in the direction of travel for receiving the
furnish.
[0056] When a multi-layered felted mat 32 is formed, a plurality of
hoppers usually are used with each having a dispensing or forming
head extending across the width of the carriage for successively
depositing a separate layer of the furnish as the tray is moved
beneath the forming heads. Following this, the tray is taken to the
mold to place the felted mat within the cavity of bottom mold 28,
by sliding the tray out from under mat 32.
[0057] In order to produce molded wood flake parts 12 having the
desired edge density characteristics without excessive blistering
and spring back, the felted mat should preferably have a
substantially uniform thickness and the wood flakes 22 should lie
substantially flat in a horizontal plane parallel to the surface of
the carriage and be randomly oriented relative to each other in
that plane. The uniformity of the mat thickness can be controlled
by depositing two or more layers of the furnish (i.e., wood flakes
and binder) on the carriage and metering the flow of furnish from
the forming heads.
[0058] Spacing the forming heads above the carriage so the wood
flakes 22 must drop from about 1 foot to about 3 feet from the
heads en route to the carriage can enhance the desired random
orientation of the wood flakes 22. As the flat wood flakes 22 fall
from that height, they tend to spiral downwardly and land generally
flat in a random pattern. Wider wood flakes within the range
discussed above enhance this action. A scalper or similar device
spaced above the carriage can be used to ensure uniform thickness
or depth of the mat, however, such means usually tend to align the
top layer of wood flakes 22, i.e., eliminate the desired random
orientation. Accordingly, the thickness of the mat that would
optimally have the nominal part thickness T (FIG. 3) is preferably
controlled, by closely metering the flow of furnish from the
forming heads. The mat thickness that would optimally have the
nominal part thickness T will vary depending upon such factors as
the size and shape of the wood flakes 22, the particular technique
used for forming the mat 32, the desired thickness and density of
the molded wood flake part 12 produced, the configuration of the
molded wood flake part 12, and the molding pressure to be used.
However, as discussed above, felted mats 32 will be compressed to
varying thicknesses by mold 20 due to unavoidable inconsistencies
from mat 32, spring back, over-compression, or the like.
[0059] Following the production of the felted mat 32 and placement
of the felted mat 32 within the cavity 30 of the mold 20, the
felted mat 32 is compressed and cured under heat and pressure when
the top mold die 26 engages the bottom mold die 28. Mat 32 is
compressed preferably to a density of from about 40 to about 45
pounds per cubic foot, more preferably about 43 pounds per cubic
foot. During this molding process, the extension 23 pushes through
the binder coated wood flakes 22 of the felted mat 32 and is
received by the extension receiving cavity 27. This action forms
the slots 18 which defines the perimeter of flexible spring members
14. Any holes 34 will also be created during this molding step as
detailed above.
[0060] The felted mat 32 is thus compressed and cured between the
top mold die 26 and the bottom mold 28 to become the molded wood
flake part 12. After the molded wood flake part 12 is produced, any
flashing and any plugs are removed by conventional means to reveal
flexible spring members 14 and holes 34.
Molded Wood Flake Article Details:
[0061] The process as described above can be used to fabricate
three-dimensional articles, such as represented by the molded wood
flake back 12 of chair 10 shown in FIG. 1. Back 12 includes
integral flexible spring members 14, as more particularly described
below. In particular, a molded wood flake article, such as back 12,
is fabricated to include at least one flexible spring member 14
which is narrower then the width of the article in which the
flexible spring member 14 is disposed. Flexible spring member 14 is
fabricated as a cantilevered member and more particularly as a
cantilevered spring which can flex independently of the molded wood
flake support.
[0062] Cantilevered flexible spring member 14 can be used in any
article or situation wherein an independently flexible spring
member is desired. For example, article 12 may be a molded chair
back, as seen in FIG. 1, wherein one or more flexible spring
members 14 are molded within the back. The discussion below,
therefore, is directed to the furniture industry. This is, however,
merely a preferred embodiment, and various other articles, both
within the furniture industry and outside thereof, may be
fabricated using the molded wood flake article with the inventive
integrally formed flexible spring member.
[0063] In a first embodiment as shown in FIGS. 1 and 4, molded wood
flake article 12 comprises the back of a chair 10 including a seat
11 and the back 12, both coupled to each other and to chair legs 15
in a conventional manner. With respect to FIG. 4, back 12 includes
at least one cantilevered flexible spring member 14 which can
independently flex. In the preferred embodiment, a plurality of
spaced-apart flexible spring members 14 are illustrated wherein
each flexible spring member 14 can flex independently of each other
as well as with respect to seat back 12. Flexible spring members 14
are fabricated by molding, machining, cutting or otherwise creating
at least one slot 18 in molded seat back 12, thereby creating the
at least one flexible cantilevered spring member 14 which is
narrower than the width W (FIG. 4) of back 12. In the preferred
embodiment, a plurality of longitudinal slots 18 are disposed
vertically with respect to a vertical axis of seat back 12, and
intermediate sides 17 and 19 thereof, to define a plurality of
longitudinal flexible spring members 14 laterally disposed
adjacently to one another. The flexible spring members 14 are
connected, or more particularly integrally formed to the seat back,
on base section 16 thereof, while the opposite ends on top 13
remain free to allow flexation of members 14. The free ends 13 of
seat back springs 14 may optionally be covered by a sheath 130 of
mesh material stapled in place as described in detail below in
connection with FIGS. 19 and 20. All of the seat backs of the
various embodiments herein may optionally include such a sheath.
Back 12 may be installed adjacent the rear of seat 11, as
illustrated in FIG. 1, thereby providing a chair 10 which includes
a flexible back member allowing a user to be comfortably seated
therein.
[0064] The presence of flexible members 14 allow for turning
movement to take place within the chair without having to move the
seat thereof. Additionally, flexible members 14 permit back portion
12 to conform to the shape of the user, thereby promoting greater
comfort. Further, the back 12 and rear edge of seat 11, as well as
flexible members 14, can be curved as shown in FIG. 1 to promote
greater support. Further yet, flexible members 14 can be made any
length, thereby offering the maximum flexibility and design
characteristics which can be tailored as the specific requirements
dictate.
[0065] In this embodiment, because the total weight disposed
against back 12 is supported by a plurality of flexible spring
members 14, the total load and/or deflection experienced by a given
flexible member 14 will be divided over the total number of
flexible members 14 supporting the weight.
[0066] The following equations define the expected amount of
deflection and sheer stress that a given flexible member 14 should
experience. In each equation n=number of flexible members. D = wl 3
3 .times. .times. EI / n ##EQU1## Sheer .times. .times. Stress
.times. .times. S s .times. .times. ( flexible .times. .times.
member ) = 3 2 .times. ( load ) 2 .times. .times. BH / n
##EQU1.2##
[0067] where: [0068] D=deflection; [0069] w=0.18.times.(weight of
user); [0070] l=length or height of member; [0071] E=elastic
modulus of engineered wood; [0072] I=moment of inertia; [0073]
B=member thickness; and [0074] H=member height.
[0075] For the seat only, use the following formula to calculate
deflection and to consider the different location of the weight of
the user. D seat = W 6 .times. .times. EI .times. ( 2 .times.
.times. l 3 - 3 .times. .times. l 2 .times. a - a 3 ) / n
##EQU2##
[0076] where: [0077] D=deflection of flexible member (14A', 14F,
14I); [0078] W=0.82.times.W, where W is the weight of user; [0079]
a=distance from the front end of spring member (i.e., toward the
back of the chair) to a point where the concentrated load is
applied. This point is usually =1/3 l.
[0080] Chair 10, and more particularly back 12, is fabricated from
the aforementioned wood flake molding process. In the preferred
embodiment flexible spring members 14 are integrally formed by
molding appropriate slots or channels 18 into seat back 12 during
the molding process. However, the channels 18 for flexible spring
members 14 can be fabricated by numerous other methods, such as
cutting, machining, sawing, or the like. Thus, when referring to
the spring members as being "integrally formed" with a support,
this refers to spring members which are integral with the
surrounding support, such as base section or end 16 (FIG. 1), as
opposed to being attached thereto by other means such as mechanical
fasteners. The thickness of back 12 may range from about,
preferably, 3/8 inch to 5/8 inch, and more preferably about 1/2
inch to 9/16 inch. Further, although flexible spring members 14
have been described with respect to back 12, a seat 11' (FIG. 5)
may also, either alone or in combination with back 12, incorporate
flexible spring members 14 therein. Further, although the preferred
embodiment of back 12 is fabricated separately from seat 11, both
may be molded together in a single molding operation thereby
creating a one-piece molded chair including a seat 11 and a back 12
wherein either or both portions may include flexible spring members
14 as illustrated in FIG. 6 (described in more detail below). As
such, in the preferred embodiment, a robust yet flexible chair
including independently flexible spring members, wherein the
members can adjust to the seated user, has been created without
adding any additional manufacturing steps or additional parts
thereto.
[0081] FIG. 6 discloses an embodiment of the present invention in
which a chair 40 has an integral seat 42 and back 44. Similar parts
appearing in FIGS. 1-5 and FIG. 6, respectively, are represented by
the same, corresponding reference numeral, except for the suffix
"A" in the numerals of the latter. With respect to FIG. 6, back 44
includes a plurality of flexible spring members 14A and seat 42
includes a flexible member 14A', thereby incorporating the
integrally formed flexible member in both the seat and the back,
respectively, providing a dual cantilevered chair 40. Cantilevered
seat 42 and its spring 14A' and back 44 with channels 18A between
cantilevered springs 14A are constructed in the same manner as
previously described in connection with the seating elements of
FIGS. 1-5. Back 44 and/or seat 42 may alternately include a single
flexible member 14A or a series of spaced-apart flexible members,
respectively. In this embodiment, the single spring member 14A' is
defined by a U-shaped channel 41. The chair form 40 may be covered
by a suitable upholstery padding and fabric, as illustrated in
phantom in the embodiment of FIG. 16, and is conventionally mounted
to a base including one or more legs to define a completed
chair.
[0082] FIGS. 7 and 8 disclose another embodiment of the present
invention with a chair 50 having a back 54 with single down-turned
flexible spring member 14B. Similar parts appearing in FIGS. 1-5
and FIGS. 7-8, respectively, are represented by the same,
corresponding reference numeral, except for the suffix "B" in the
numerals of the latter. Chair 50 includes a seat 52 and a back 54
which includes the cantilevered flexible spring member 14B which
can independently flex. As described above with respect to the
first embodiment, flexible spring member 14B may be fabricated by
molding, machining, cutting or otherwise creating at least one slot
51 in molded seat back 54. In the preferred embodiment, a pair of
spaced-apart longitudinal slots 51 are disposed vertically with
respect to the vertical axis of seat back 54 and intermediate to
sides 53 and 55 thereof to define the flexible spring member 14B.
Flexible spring member 14B is integrally formed to the back top end
section 56 while the opposite end 57 of spring 14B remains free to
allow flexation. In this embodiment, free end portion 57 is
directed downwardly and forwardly to provide a flexible support for
the lower back. In this embodiment, back 54 and seat 52 are
attached to one another utilizing angle brackets 60, thereby
providing an additional cantilevered spring for seat back 54. The
chair 50 also conventionally includes legs 58 which are secured to
seat 52 in a conventional manner. Seat 52 and back 54 can both be
molded of wood flakes in the process described earlier.
[0083] As seen in FIG. 8, cantilever flexible member 14B displays
two modes of cantilever action. Main back sections 59 on either
side of spring 14B display a main deflection D1 relative to seat
52, while flexible member 14B displays a smaller deflection D2
relative to back sections 59. The deflection of each main section
59 and flexible member 14B can be calculated using the same basic
set of cantilever beam equations. D=Wl.sup.3/3EI/n
[0084] where: [0085] D=deflection; [0086] W=0.18.times.(w) where w
is the weight of user; [0087] l=length or height of member; [0088]
E=elastic modulus of engineered wood; [0089] n=number of springs
(n=1 in FIG. 8); and [0090] I=moment of inertia, [0091] and
I=BH.sup.3/12
[0092] where; [0093] B=member thickness; and [0094] H=member
height.
[0095] As can be seen from the above equations, D1 and D2 will vary
relative to one another based solely upon their effective length or
height, as all other variables are the same for each equation. The
potential total deflection of flexible member 14B is determined by
adding D1 and the opposite direction D2 together. Their effects are
cumulative because main back sections 59 act as a secondary
floating cantilever. Chair 50 also can be upholstered, as shown by
the upholstery and padding shown in phantom in the embodiment of
FIG. 16 or as seen in FIG. 9.
[0096] FIG. 9 illustrates a further embodiment of chair 50
including a foam pad 62 which provides an additional spring member,
wherein the combined operation of flexible member 14B and foam
member 62 provides chair 50 with ample lumbar support and comfort
for a user seated thereon. Additionally, a foam cushion 64 covered
by a layer of fabric 65 is also provided to complete back 54 of
chair 50.
[0097] The chair 50' of FIGS. 10 and 11 is another embodiment of
the present invention having a single down-turned forwardly
extending flexible spring member 14C. Since chair 50' is similar to
the previously described chair 50, similar parts appearing in FIGS.
10-11 are represented by the same, corresponding reference numeral,
except for the suffix superscript (') in the numerals of the
latter. Chair 50 includes a seat portion 52' and a back 54' which
includes a cantilevered flexible spring member 14C which is formed
to extend outwardly from the plane of the seat 54' back toward the
seat 52'. It independently flexes and creates a lumbar support to
provide a more supportive lower back structure.
[0098] FIG. 12 generally designates a chair 70 which is another
embodiment of the present invention and has a downwardly extending
flexible spring member 14D. In this embodiment, chair 70 includes a
seat and back 74 molded and joined in a manner similar to the chair
shown in FIGS. 1-4. The chair includes support legs 75 extending
from seat 72. The back 74 of chair 70 includes a single flexible
spring member 14D with a free end 77 which terminates into main
section of back 74. Spring 14D is defined by a generally U-shaped
channel 78 formed in back 74. This design provides a somewhat
stiffer but yet flexible back to the chair. The back 74 is
concavely formed, as is spring 14D, to comfortably receive a
person's torso, although in some embodiments a straight back with a
similar spring 14D may be preferred.
[0099] In the embodiments described above, the springs are formed
from the molded wood flake material preferably by integrally
molding channels to define one or more springs. The channel or
channels typically have a width of about 1/2 inch, while the
thickness of the cantilevered spring material is from about 3/8
inch to about 5/8 inch. Frequently, when springs are made for
seating, such as shown in FIG. 5, the springs will be secured to a
box-like framework defining, for example, a chair base to which
legs and a back are subsequently attached, typically using
fasteners such as threaded fasteners.
[0100] A sofa 80 embodying the present invention is shown in FIGS.
13 and 14. The sofa or wide chair 80 includes a seat 82 and a back
84 which includes a plurality of cantilevered flexible arcuately
shaped spring members 14E which can independently flex and are
designed to replace the metal springs that have been used in the
prior art. As illustrated, arcuate flexible spring members 14E
include connected lower ends 81 which are attached, affixed or
integrally formed with a base support 83. Spring members 14E have
free ends 85 which terminate and rest on a foam pad member 86
attached to a vertically extending back member 87. Foam member 86
further enhances the spring effect and quality of flexible spring
members 14E and is made of a high density foam which is glued or
otherwise affixed to back member 87. As such, foam member 86
prevents any potentially damaging contact between molded wood flake
springs 14E and back member 87, as well as provides an additional
spring element for enhanced support. Foam member 86 and back member
87 may be omitted to provide a plurality of ends 85 which are free
to flex as described in the previous embodiments.
[0101] In the preferred embodiment of a sofa back 84,
interconnecting each flexible member 14E and located approximately
.cndot. to 1/2 of the distance up from base 83 is lumbar foam
support 88. Lumbar foam support 88 is connected by a suitable
adhesive to each of the plurality of flexible members 14E and
couples the springs to one another to provide co-joint back support
and offers the additional advantage of providing a lumbar support
for the back of a user. Additionally, a foam sheet 89 covers
flexible members 14D and lumbar foam member 88. Foam material 89 is
formed from a flat sheet of foam, which is relatively inexpensive
as it does not need to be pre-shaped or provided with a particular
contour. During the course of mounting material 89 in place with
fabric covering 90, it takes the appropriate shape needed. An
additional advantage associated with foam material 89 is that is
can be manufactured to any desired size and length and/or can be
cut from a larger sheet of foam. The "cushiony" feel provided by
the combination of foam sheet 89, lumbar foam member 88, top foam
member 86 and flexible members 14E eliminates the need for batting
to achieve the desire degree of softness. This is especially
advantageous since the elimination of the batting between the foam
slab and the fabric reduces the material and/or labor costs of
constructing sofa back 84.
[0102] In a preferred embodiment, a single foam member is used for
members 86 and 88 which extends across flexible members 14E. These
members may be fabricated from numerous materials which are
commonly known within the art. However, the type of foam ideally
used is a 2.5-3.0 pound foam. Base 83 and back member 87 may also
be molded of wood flake material and may include support blocks 92
(FIG. 14) at spaced locations along their junction 94 for adding
rigidity to this connection. Base member 83 is suitably secured to
seat 82 by conventional brackets or by extending back member 87
below member 83 and coupling the back member to a seat forming
support member which, as noted above, can also include the spring
construction of this invention. Although not illustrated in FIGS.
13 and 14, it is to be understood that molded wood flake springs
could also be employed for seat 82 as in the design of FIG. 5 or
the seat of FIG. 6.
[0103] FIGS. 15 and 16 show an alternative embodiment of an
article, such as a chair 100, in which the molded wood flaked
seating section 110 integrally includes a front lower section 112
forming part of the chair frame. As best seen in FIG. 16, member
110 includes cantilever spring members 14F which are spaced from
one another by integrally molded channels 118 having a width of
approximately 1/2 inch. The channels extend downwardly into the
vertically extending section 112 and terminate in a circular
aperture 114 which serves as a stress relief member for the
cantilevered springs 14F extending from the vertical base section
112. The apertures for a channel width of 1/2 inch are
approximately 3/4 inch in diameter and preferably are integrally
molded by employing a mold insert during molding of chair base 110.
In some embodiments, however, it may be desirable to drill the
circular apertures 114. The chair base is completed by a pair of
molded wood flake sides 102 and 104 and a back member 106. Sides
102 and 104 include downwardly depending slots 105 which receive
the integrally wood flake molded chair back 120, as seen in FIG.
15. The back 120 includes a notch 121 on each of the corners such
that the back can extend into notches 105 in side members 102 and
104, allowing the interlocking of the back to the side members and
allowing fastening screws 101 to extend through the apertures 103
to secure the back to the side members 102 and 104, as seen in
FIGS. 16 and 17.
[0104] The back 120 likewise includes three integrally molded
spring members 14G which are defined by channels 108 extending
therebetween downwardly to the integral lower section 122 of back
120. The sides 102 and 104, back member 106, seat section 110, and
seat back 120 are secured to one another by threaded fasteners 101
which extend through the apertures 103 formed at various locations
in the respective members, as best seen in FIG. 15, for securing
the seat elements together, as illustrated in FIG. 16. Thus, in the
embodiment shown in FIGS. 15 and 16, the chair base includes an
integrated wood flake molded section which integrally forms a frame
member for the bases. Each of the members 102, 104, 106, 110, and
120 are molded utilizing a wood flake mat, such as mat 32 shown in
FIG. 2, and a suitable mold configuration in the process identified
above. The chair 100 may include a suitable fabric and upholstery
covering 113, shown in phantom in FIG. 16, and, of course, support
legs 117 conventionally coupled to the frame forming elements of
the chair base (i.e., 102, 104, 106, 112).
[0105] The chair design, as shown in FIGS. 15 and 16, can be
modified as shown by chair 100' in FIG. 17 by providing a back
member 106' which extends upwardly approximately midway through the
back panel 120 and which includes a foam pad 124 which extends
behind the cantilevered spring members 14G of back 120 to provide
additional support for the back 120. The foam pad 124 can have a
density of from 21/2 to 3 pounds and is bonded to the back member
106' and the back surface of spring members 14G by suitable bonding
agents in a conventional manner. The foam block 124 extends
substantially the width of back 120 and interconnects the
cantilevered springs 14G to one another to allow cooperative
bending of the seat back upon application of pressure from a
person's back. In both embodiments of the chairs shown in FIGS.
15-17, the outer spring members 14F are spaced from the respective
side panels 102 and 104 to allow clearance and flexure of the two
outermost spring members. Likewise, the free ends of the spring
members 14F are spaced from the lower section 122 of back 120 to
allow their flexure without contacting the seat back.
[0106] FIG. 18 illustrates an alternative embodiment of a similarly
formed chair 100'' with the corresponding elements identified with
the same reference numeral as those used in FIGS. 15-17. The chair
100'' differs in that the base 110A has a plurality of tapered
springs 14H which taper inwardly in a rearward direction as seen in
FIG. 18. This construction provides spring members 14H for the seat
100'' which has a softer, less stiff feel than the substantially
uniform 2 inch wide spring fingers 14F of the previous embodiments.
As in the previous embodiments, the seat section 110A includes an
integral frame member 112 and channels 118A, which are configured
to define the inwardly, rearwardly tapered spring members 14H.
Thus, channels 118 are generally elongated triangular channels, as
best seen in FIG. 18, to define the tapered spring arms 14H.
Although in the embodiment shown in FIG. 18, the taper of arms 14H
begin approximately midway toward the rear of the seat 110A, the
tapers can start near the bend 111 between the horizontally
extending fingers 14H and the generally vertically extending
integral frame member 112.
[0107] FIGS. 19 and 20 illustrate a further improvement to the
chair design 100 of FIGS. 15 and 16 by which the free floating ends
of spring members 14G forming the seat back 120 are intercoupled by
an elastomeric mesh 130 which is fitted over the free ends of
spring members 14G and stapled to the outermost of the spring
members, as shown in the cross section of FIG. 20, by staples 132
to loosely couple the ends of spring members 14G to one another
such that the deflection of members 14G will co-jointly affect one
another. In FIGS. 19 and 20, sheath 130 had a length "L" of
approximately 2 to 3 inches and covered the upper and lower
surfaces of the free ends of spring arms 14G. Sheath 130 tends to
prevent overstress of individual spring members 14G and limit the
overall action of the springs. The sheath 130 is an open mesh
elastomeric stretch material made of polyester or vinyl. One
webbing which has been used is commercially available from Bruin
Plastics Company, Inc. as 9.times.9 vinyl coated mesh. Although the
sheath 130 in the embodiment shown in FIGS. 19 and 20 extends
around the free ends of the spring members 14G, in some embodiments
it may be desirable to provide the mesh at other locations, such as
by providing wrapping around the spring members 14G near the midway
of the seat back to likewise loosely intercouple the springs
together. Sheath 130.also serves to contain the free ends of spring
members 14G in the unlikely event one of the spring members should
fracture during use, thereby substantially maintaining the
integrity of the seat base in such an event.
[0108] Another modification to the chair 100 shown in FIGS. 15 and
16 is illustrated in FIGS. 21 and 22 in which the chair 100
includes an underlying support web of elastomeric material 140
which can be stapled to the side members 102 and 104 of the chair
base by staples 142. One or more strips of webbing 140 can be
positioned, as seen in FIGS. 21 and 22, at suitable locations, such
as midway in the seat 110 to underlie and provide additional
support across and under spring members 14F. The attachment of web
140 under the seats can be selected to move forwardly or rearwardly
depending upon the feel desired for the seat section 110. In some
cases, it may be desirable to provide an adjustable intercoupling
of the attachment of web 140, as shown by the pictorial diagram of
FIG. 23.
[0109] In FIG. 23, a movable attachment member 145 is provided for
the webbing 140 and can be secured to the side members 102 and 104
by providing longitudinally and vertically extending slot 146 in
the side members 102 and 104 and a suitable clamping structure 147
to secure member 145 and web 140 coupled thereto in a selected,
vertically adjustable position, allowing for motion along a
vertical axis Y (shown in FIG. 23) or in a horizontal direction X
(shown in FIG. 23) to position the web 140 forwardly or rearwardly
in seat section 110 and either in contact with the undersurface of
fingers 14F or slightly spaced therefrom such that the spring
members 14F can deflect initially without engaging supporting web
140. The clamp member 147 can be a pair of plates which engage
opposite sides of side members 102 and 104 and which include
suitable adjustment thumb screws 115 reachable from the inner side
of side members 102, 104 such that the feel of the chair seat can
be selectively adjusted by either the chair manufacturer or by the
purchaser of the chair, if desired. Thus, depending upon, for
example, the weight of the user, it may be desirable to have web
140 moved more rearwardly to provide a greater degree of support
for the free ends of spring members 14F and into contact with the
undersurface of the free ends of spring members 14F to provide
maximum additional support. For a softer feel, the webbing 140 can
be moved forwardly toward the front edge of the chair 100 and/or
moved downwardly such that the spring member 14F can initially flex
without engaging the supporting underlying web. The web may have a
width along the X axis of about 3 inches and limits the deflection
of the members 14F from about 20 to about 40 percent depending on
the positioning of the web or whether one or more webs are used.
One 3 inch wide web material which has been used is a polypropylene
spiral wrap natural extruded rubber threads cross-woven with
polypropylene thread which is commercially available from Ultraflex
Corporation.
[0110] FIG. 24 shows an alternative embodiment of a chair 200 which
is substantially identical to chair 100 shown in FIGS. 15 and 16
with the exception that the seating spring members 141 each
integrally include a concave reinforcing indentation 202 which
extends from the front frame wall 212 rearwardly to the free end of
each of the springs 141. The indentations are molded into the seat
section 210 together with the channels 218 which define each of the
spring members 141. As in the previous embodiment, the channels 218
terminate in a circular aperture 214 in the frame member 212, which
is assembled as in the previous embodiment with side members 102
and 104 and a back member 120 having spring members 14G and formed
by channels 108 as in the prior embodiments. The addition of
indentations 202 increases the spring constant significantly to
provide a much stiffer feel to the seat section 210. In one
embodiment of the invention with a spring thickness of 1/2 inch and
the width of the springs being from 2 to 3 inches wide, the
indentations 202 were approximately 1/2 inch deep and 1 inch wide
with no greater than a 3/8 inch radius at the corners 203 and 207
shown in FIG. 25.
[0111] In the above embodiments, a molded wood flake support member
has been described which includes an integrally formed molded wood
flake flexible spring. The flexible spring member acts as a
cantilevered spring thereby flexibly supporting the user that is
seated therein. The above embodiments have been particularly
directed to the furniture industry and more particularly to the
seating industry. However, these embodiments represent only the
preferred embodiments and are not meant to be limiting in any
manner. The above inventive integral flexible spring can be
utilized in various ways and be fabricated into varied articles.
Hence, the above description is that of the preferred embodiments
only.
[0112] Modifications of the invention will occur to those skilled
in the art and to those who make or use the invention. Therefore,
it is understood that the embodiment described above is merely for
illustrative purposes and not intended to limit the scope of the
invention, which is defined by the following claims as interpreted
according to the principles of patent law, including the Doctrine
of Equivalents.
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