U.S. patent application number 11/731560 was filed with the patent office on 2007-10-04 for tabletop for outdoor use reinforced with foam material and metal frame.
Invention is credited to Oliver Wang.
Application Number | 20070227416 11/731560 |
Document ID | / |
Family ID | 46327629 |
Filed Date | 2007-10-04 |
United States Patent
Application |
20070227416 |
Kind Code |
A1 |
Wang; Oliver |
October 4, 2007 |
Tabletop for outdoor use reinforced with foam material and metal
frame
Abstract
A tabletop for outdoor use is disclosed. The tabletop is formed
of a plastic support frame and plastic sheet, which form a U-shaped
space. The tabletop is reinforced with a metal frame within the
U-shaped space, with the remainder of the space filled with a foam
material. The table may further include a coloring layer which
resembles stone material for decorative purposes. The coloring
layer is attached to the plate by a resin layer and may include an
optional fiber mesh embedded within the resin.
Inventors: |
Wang; Oliver; (Millbrae,
CA) |
Correspondence
Address: |
WILLIAMS MULLEN
222 CENTRAL PARK AVENUE
SUITE 1700
VIRGINIA BEACH
VA
23462-3035
US
|
Family ID: |
46327629 |
Appl. No.: |
11/731560 |
Filed: |
March 30, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10968502 |
Oct 19, 2004 |
|
|
|
11731560 |
Mar 30, 2007 |
|
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Current U.S.
Class: |
108/161 |
Current CPC
Class: |
A47B 13/08 20130101;
A47B 37/04 20130101; A47B 2200/001 20130101; A47B 13/086 20130101;
A47B 96/205 20130101 |
Class at
Publication: |
108/161 |
International
Class: |
A47B 13/02 20060101
A47B013/02 |
Claims
1. A tabletop for use on an outdoor table comprising: a
substantially flat sheet of fiberglass reinforced plastic; and a
supporting frame comprising: a layer of fiberglass reinforced
plastic including substantially U-shaped cross-members extending
laterally with respect to the flat sheet, the layer of fiberglass
reinforced plastic underlying the flat sheet and forming an
enclosed space between the sheet and the U-shaped cross-members; a
metal frame within the enclosed space; and a foam material
substantially filling the enclosed space and surrounding the metal
frame.
2. The tabletop of claim 1, further comprising a coloring layer
adhered to the top surface of the flat sheet with a layer of
adhesive material.
3. The tabletop of claim 2, wherein the adhesive material is a
resin.
4. The tabletop of claim 3, wherein the resin is one or more of an
unsaturated polyester resin, a vinyl ester resin, or an epoxy
resin.
5. The tabletop of claim 2, wherein the coloring layer resembles
stone.
6. The tabletop of claim 5, wherein the coloring layer is comprised
of one or more of stone, marble, clay, slate, granite, tile,
ceramic, or porcelain.
7. The tabletop of claim 2, further comprising a fiber mesh within
the adhesive material.
8. The tabletop of claim 1, wherein the foam material is formed of
expandable polystyrene or expandable polyurethane.
9. The tabletop of claim 1, wherein the metal frame is formed of
one or more of aluminum, iron, or steel.
10. A tabletop for use on an outdoor table comprising: a
substantially flat sheet of fiberglass reinforced plastic; a
fiberglass reinforced plastic supporting frame including
substantially U-shaped cross-members extending laterally within the
supporting frame, the supporting frame underlying the flat sheet
and forming an enclosed space between the plate and the U-shaped
cross-members of the supporting frame; a metal frame within the
enclosed space; and a foam material substantially filling the
enclosed space and surrounding the metal frame.
11. The tabletop of claim 10, further comprising a coloring layer
adhered to the top surface of the flat sheet with a layer of
adhesive material.
12. The tabletop of claim 11, wherein the adhesive material is a
resin.
13. The tabletop of claim 12, wherein the resin is one or more of
an unsaturated polyester resin, a vinyl ester resin, or an epoxy
resin.
14. The tabletop of claim 11, wherein the coloring layer resembles
stone.
15. The tabletop of claim 14, wherein the coloring layer is
comprised of one or more of stone, marble, clay, slate, granite,
tile, ceramic, or porcelain.
16. The tabletop of claim 11, further comprising a fiber mesh
within the adhesive material.
17. The tabletop of claim 10, wherein the foam material is formed
of expandable polystyrene or expandable polyurethane.
18. The tabletop of claim 10, wherein the metal frame is formed of
one or more of aluminum, iron, or steel.
19. A tabletop for use on an outdoor table comprising: a
substantially flat sheet of fiberglass reinforced plastic; a
fiberglass reinforced plastic supporting frame including
substantially U-shaped cross-members extending laterally within the
supporting frame, the supporting frame underlying the plate and
forming an enclosed space between the plate and the U-shaped
cross-members of the supporting frame; a metal frame formed of
aluminum, iron, or steel within the enclosed space; a foam material
comprised of expandable polystyrene or expandable polyurethane
substantially filling the enclosed space and surrounding the metal
frame; and a coloring layer adhered to the top surface of the flat
sheet with a layer of adhesive material.
20. The tabletop of claim 19, further comprising a fiber mesh
within the adhesive material.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation-in-part of U.S.
application Ser. No. 10/968,502, filed Oct. 19, 2004, the entire
contents of which is incorporated herein by reference.
FIELD OF INVENTION
[0002] The present invention relates generally to a tabletop, and
more particularly to a tabletop for outdoor use that is reinforced
with foam material and a metal frame.
BACKGROUND OF THE INVENTION
[0003] Tabletops are generally made of wood. However, wood
tabletops are often subject to deterioration due to acidic, basic,
air or water conditions over time. Therefore, tabletops, especially
those for outdoor uses, are now made of other materials such as
plastics, metals, or composite materials.
[0004] Since plastic materials are light weight and can more
readily withstand harsh environmental conditions, the majority of
tabletops for outdoor use are currently made of plastic materials.
However, tabletops made of bulky plastic materials are too heavy in
weight, especially for portable tables. Consequently, tabletops
with hollow supporting frames or with plastic or foam material
supporting frames have been developed. The tables that include foam
material supporting frames instead of a pure plastic framework
greatly reduce the weight of a table top. Such table tops, by
themselves, generally do not provide enough support strength for
forming larger, heavier tables. Examples of larger tables might
include rectangular or oval-shaped tables which may have diameters
of 40 inches, 72 inches, or more. Tables of such large sizes are
becoming more and more popular. Tables of such large sizes have
been known to warp when the temperature is extremely high, or in
tense sunlight, as the center of the tables may sink or become
arched. The shape of the tables also contributes to this problem.
Longer tables more easily warp in the center.
[0005] The type of binder used for outdoor table tops may also be a
factor in warping. Polyester resin is a frequently used binder due
to its being relatively inexpensive. The drawback of polyester
resin is its thermal expansion and contraction properties. The
resin tends to expand significantly when the temperature goes up
and contract when the temperature drops which causes it to change
volume. If the frame does not provide sufficient supporting force
to resist bending, the whole table will warp. If the deformation
and temperature cycling is frequent, the table may even crack.
Thus, there is a need for low cost tabletops with sufficient
support strength to resist warping, and sufficiently light weight
to be portable.
[0006] U.S. Pat. No. 6,694,897 discloses a folding table that
includes a shell filled with urethane foam that supports the table
top. The table appears to be for indoor use and does not include a
heavy stone top. There is no disclosure of a metal frame within the
core which is surrounded by the foam material.
[0007] U.S. Pat. No. 6,915,749 discloses a table top that includes
a metal base, which includes a metal plate and a metal frame. The
frame includes square metal tubes having dimensions of 10 mm. The
metal plate has a thickness of 0.5-0.8 mm. This table is rather
heavy, as it includes a metal frame and a metal plate. Also, the
adhesion of such a table to binder, which is often unsaturated poly
resin, is not very good. The adhesion between petroleum-based
materials and metal is not as strong as adhesion between materials
of the same base. There are several problems with the disclosed
bonding. First, if there is some entrapped air between the support
base frame and the binder layer, the air weakens the bonding and
when the resin expands or contracts with temperature variation, the
expansion or contraction force is uneven causing the base plate and
binder to separate. Metal generally expands and contracts to a
significantly lower extent than resin or plastic based materials.
Second, the metal tubes are also susceptible to corrosion due to
moisture in the environment, as well as to water and moisture used
in polishing or finishing the table's stone surface. Corrosion or
rusting of the frame causes it to crack and separate due to
temperature changes. When the tabletop is ground, polished, and
water-flushed, the water could penetrate deep through the resin
layer and down to the metal base plate. Then enclosed metal may
corrode and separate further from the resin layer later. When cut
stone or similar material is used on the tabletops, and when resin
is combined with the stone material, there may also be fine slits
at stone-resin bonding face where the moisture and water may
penetrate.
SUMMARY OF THE INVENTION
[0008] The invention relates to a tabletop for use on an outdoor
table that includes a substantially flat sheet of fiberglass
reinforced plastic and a supporting frame. The supporting frame
includes a layer of fiberglass reinforced plastic including
substantially U-shaped cross-members extending laterally with
respect to the flat sheet. The layer of fiberglass reinforced
plastic underlies the flat sheet and forms an enclosed space
between the sheet and the U-shaped cross-members. The supporting
frame also includes a metal frame within the enclosed space and a
foam material substantially filling the enclosed space and
surrounding the metal frame. For the purposes of this invention,
U-shape merely means any shape open at one end, capable of
receiving a metal frame, and capable of being enclosed by the sheet
and filled with foam material.
[0009] The invention further relates to a tabletop for use on an
outdoor table that includes a substantially flat sheet of
fiberglass reinforced plastic, a fiberglass reinforced plastic
supporting frame including substantially U-shaped cross-members
extending laterally within the supporting frame, a metal frame, and
a foam material. The supporting frame underlies the flat sheet and
forms an enclosed space between the sheet and the U-shaped
cross-members of the supporting frame. The metal frame is within
the enclosed space and is surrounded by foam material which
substantially fills the enclosed space.
[0010] The tabletop may further include a coloring layer that
resembles stone and may be formed of one or more of stone, marble,
clay, slate, granite, tile, ceramic, or porcelain. The coloring
layer is attached to the plate by an adhesive layer that may be
formed of a resin of one or more of an unsaturated polyester resin,
a vinyl ester resin, or an epoxy resin. An optional mesh may be
included within the adhesive material. The flat sheet and the
supporting frame may be formed of fiberglass reinforced plastic,
the foam may be formed of expandable polystyrene, expandable
polyurethane, etc., and the metal frame may be formed of one or
more of aluminum, iron, or steel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The invention will be better understood in relation to the
attached drawings illustrating preferred embodiments, wherein:
[0012] FIG. 1 is a perspective view of a tabletop of the present
invention;
[0013] FIG. 2 is a cross-sectional view taken along line II-II in
FIG. 1;
[0014] FIG. 3 is a cross-sectional view of an alternate embodiment
according to the invention; and
[0015] FIG. 4 is a perspective view of an embodiment of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] The present invention provides a tabletop for outdoor use
that is light weight and yet maintains support strength. The
tabletop has sufficient strength to resist deformation or warping.
Further, the tabletop is resistant to common outdoor environmental
conditions, such as acidic, basic, air, and wet conditions.
[0017] Referring to FIG. 1, a perspective view of a tabletop 1 of
the present invention is illustrated. As shown, the tabletop 1
comprises a sheet of plastic 10 and a plastic supporting frame 20.
The plastic supporting frame 20 is covered by and attached to the
sheet of plastic 10. The sheet of plastic 10 and the plastic
supporting frame 20 may both be formed of fiberglass reinforced
plastic (FRP) or similar material, the mat and resin layers of
which may incidentally merge into a single multi-layered FRP
structure. FRP has the additional advantages of being corrosion
resistant and low weight.
[0018] The plastic supporting frame 20 preferably comprises
cross-members 21 and a circular rim 22. The circular rim 22
surrounds the cross-members 21 and defines the shape of the
tabletop 1. The cross-members 21 extend from points on the circular
rim 22 in a chord to a corresponding point across from the starting
point. Further, additional cross-members 21 may extend
perpendicularly to the first set of cross-members 21 to form right
angles within the circular rim 22. While the arrangement of
cross-members 21 is shown in FIG. 1 as being at right angles with
respect to each other, the arrangement is not so limited. The
cross-members 21 may be arranged in any manner, so long as they
provide sufficient support for the FRP sheet 10. Rim 22 may be of
any shape desired for the perimeter of tabletop 1, described here
as circular for convenience. Spaces between cross members 21 and
rim 22 may be open, as shown in FIG. 1, filled as shown in FIG. 4
and discussed below, or may comprise some other desired structure.
Although any number of cross-members 21 may be used within the
scope of the present invention, typically at least three
cross-members 21 in each direction are used, with two cross-members
21 crossing the diameter of the circular rim 22 and intersecting in
approximately the center of the tabletop. This configuration
permits the various components of the table to be fit together
securely to prevent discontinuities therein. In this way, the table
is better able to maintain its rigidity, as well as keep moisture
from penetrating the interior parts of the table, such as the metal
frame 60 discussed below.
[0019] In the present invention shown in FIG. 3, the plastic
supporting frame 20 and foam material 30 surround the metal and
prevent the metal from being contacted by moisture, water, or any
other liquid during usage. The additional layer of the sheet of
plastic 10 on the top of the metal frame will assist in preventing
liquid or rain from penetrating into the table top, to reduce
potential corrosion or separation of the metal frame 60 from the
foam material 30. In addition, the metal frame 60 is not directly
adhered to binder, so the adhesive strength is better which reduces
separation.
[0020] Tables of the present invention may be used for outdoor use,
and are often used in conjunction with an umbrella to provide shade
or protection of individuals from rain or sun. In one embodiment of
the invention, an intersection of the cross-members 21 in includes
a hole 23, preferably but not necessarily in the center of the
tabletop 1, and a plurality of pre-drilled fastening holes 211
formed on the cross-members 21. The sheet of plastic 10 has a
similar hole corresponding to the hole 23 of the plastic supporting
frame 20 for installing an umbrella therein. In this way, the sheet
of plastic 10 and supporting frame 20 support the umbrella. As
discussed below, the fastening holes 211 of the plastic supporting
frame 20 are provided for installing at least one supporting leg
(not shown) to the tabletop 1.
[0021] Referring now to FIG. 2, a cross-sectional view taken along
line II-II in FIG. 1 is illustrated. As shown, the cross-members 21
and the circular rim 22 are made to form a space between the sheet
of plastic 10 and the plastic supporting frame 20. The
cross-members 21 have a substantially U-shaped cross-section. The
space is formed in the U-shaped region between the cross-members
21, the circular rim 22, and the sheet of plastic 10. Within this
space, foam material 30 may be added to reinforce the support
strength of the tabletop 1. The space can be formed by means of
press molding or similar processes. The foam material 30 in this
particular embodiment is chosen to be the expandable polystyrene
(EPS), expandable polyurethane, or other thermoset material
materials. The foam material will typically have a density of about
0.1 kg/m.sup.3 to 1.2 kg/m.sup.3, significantly less than the
plastic or metal of the other parts of the tabletop. Aluminum foam
is an additional alternative that may be used with the invention.
The foam material does not expand and contract with temperature
changes, in conjunction with the metal embedded therein, and thus
prevents the table from warping. The configuration of the present
invention using foam material with a metal frame avoids using bulky
plastic material, so the weight of the tabletop is greatly reduced.
The reinforced structure is strong enough for supporting the
coloring layer 40. The foam anchors the sheet of plastic 10 and
plastic supporting frame 20 to the internally situated metal frame
60; further, the foam surrounds and protects the metal frame 60
from corroding or rusting due to water or moisture in the
environment, or which may accumulate on the surface of the table
and penetrate thru coloring layer 40.
[0022] In an alternative embodiment of the invention, the plastic
supporting frame 20 may further comprise a wooden block 213
enclosed by supporting frame 20 and a fastening nut 212. For this
embodiment, the fastening nut 212 could be embedded in the wooden
block 213 and is aligned with each fastening hole 211. The wooden
block 213 and the fastening nut 212 incorporating with the
fastening hole 211 forms a fastening member of the plastic
supporting frame 20. In this particular embodiment, the fastening
nut 212 can be a square nut, a hex nut or nuts of any possible
form.
[0023] Referring again to FIG. 2, the tabletop 1 may further
comprise a coloring layer 40 adhered to the top surface of the
sheet of plastic 10 opposite to that of the plastic supporting
frame 20 through an adhesive layer 50. The coloring layer 40 will
typically contain a decorative design. For example, the coloring
layer 40 may be configured to resemble stone or similar materials.
The particular design chosen is not a limiting feature of the
present invention. The coloring layer may include one or more of
stone, marble, clay, slate, granite, tile, ceramic, porcelain or a
decorative design that resembles stone. The coloring layer may
include one or more stone material, including marble, clay, slate,
or granite, or may include tile, ceramic, porcelain or a decorative
design that resembles stone. The coloring layer may include a
mixture of stone powder, coloring powder, and calcium powder to
resemble stone.
[0024] The plastic or FRP material selected to make the tabletop 1
of the present invention is resistant to acidic, basic, air, and
wet environments, thereby giving the tabletop 1 of the present
invention a longer lifespan. Furthermore, the foam material 30 or
EPS used in the space between the cross-members 21 and the sheet of
plastic 10 significantly reduces the overall weight of the tabletop
1 of the present invention compared to conventional tabletops
employing solely or primarily metallic structures. In addition,
since the tabletop 1 of the present invention is reinforced by
using the foam material 30 in conjunction with metal frame 60, no
obvious deformation should be observed when using the tabletop 1 of
the present invention in variable, outdoor temperatures. Indeed,
the tabletop 1 should maintain its form when subjected to a
temperature of about 65.degree. C. The tabletop of the present
invention was tested in laboratories for six consecutive days. Each
day the tested tabletop was exposed to a temperature of about
65.degree. C. for over 8 hours, and was then left to cool for 30
minutes. Next, the tabletops were cooled with cold water for
another 30 minutes. The tabletops were then measured to determine
whether any warping occurred. The deformation was only about 0.5 mm
linear from the edge of the table to the center. This deformation
is not considered to be noticeable. Moreover, since all the
materials selected to make the tabletop 1 of the present invention
are non-flammable, the tabletop 1 of the present invention would
not present a fire hazard.
[0025] Referring now to FIG. 3, a cross-section of an embodiment of
the present invention is shown. FIG. 3 is a side view of the
embodiment shown in FIG. 4, discussed below. In this embodiment, a
layer of FRP sheet 20, along with the metal frame 60 and foam
material 30, constitute the supporting frame. The sheet of plastic
10 tops the U-shaped spaces formed with the cross-member 21 and the
circular rim 22 (i.e., and bonds to the FRP layer 20). Within the
space, metal frame 60 is surrounded by foam material 30, which, as
noted above, anchors and seals metal frame 60 with respect to table
top 1. In other words, the foam material 30 grips metal frame 60
for enhanced rigidity. In this way, the metal frame 60 provides
additional support for the tabletop without adding significantly to
its weight. Of course, the size of the metal frame 60 is dependant
in part upon the size of the table. A typical embodiment may
include a metal frame that is about 14 mm by 20 mm in cross-section
and having a thickness of at least about 0.1 mm. Because metal
frame 60 works with cross members 21 and circular rim 22 to provide
support (i.e., being anchored by foam material 30), less structure
is required of metal frame 60 than if it were the only source of
support; this reduces the weight and material cost of the present
invention.
[0026] A coloring layer 40 is shown attached to the sheet of
plastic 10 by an adhesive material 50, such as a resin. The
coloring layer 40 may be a solid piece which covers only the top
surface of the table, or it may be a solid piece which covers both
the top and side surfaces of the table, or it may be formed of
separate pieces having gaps therein, as shown. In the embodiment
shown in FIG. 3, the top and side pieces of the coloring layer 40
are separate, and a gap is shown between pieces of the coloring
layer 40 on the top surface of the table. Finally, a fiber mesh 45
may be embedded within the adhesive material 50. The fiber mesh 45
may be fiberglass and is optional, reinforces the adhesive material
50, and is believed to reduce the expansion and contraction of the
resin of adhesive material 50 as it goes through temperature cycles
and to add support and adhesive strength to the tabletops
overall.
[0027] Open end rivets 215 may be installed within metal frame 60
to affix at least one table leg (not shown) to the metal frame 60.
The rivets 215 may be installed during assembly to tack the metal
frame 60 to the plastic supporting frame 20 while the enclosed
space between supporting frame 20 and plastic sheet 10 is filled
with foam material 30. Preferably, once the metal frame 60 is
placed within the enclosed space in the U-shaped cross-members 21,
rivets 215 are driven through pre-drilled holes in the metal frame
60 and through the corresponding fastening holes 211 within cross
members 21 of the plastic supporting frame 20. The space is then
filled with foam material 30 which fully expands in the space. The
foam material 30 encases and anchors the metal frame 60 to the
plastic supporting frame 20 and plastic sheet 10. Of course, other
fastener types may be used, whether bolts, screws, pins, clips, or
some form of permanent affixation, such as welding.
[0028] Resins that may be used with the present invention include
unsaturated polyester resin, vinyl ester resin, epoxy resin, or
similar such resins. The resin may include a pigment to enhance its
color. The metal frame 60 in the embodiment shown in FIG. 3 helps
to keep the table from warping and provides additional strength.
The metal frame 60 may be formed of aluminum, iron, steel, or
similar metals or alloys. The invention is particularly well suited
for large tables having diameters of 40 inches or larger, up to
even 84 inches. Although a round or circular table has been
described in this application, the invention is not limited to a
table of any particular shape. Square, rectangle, or other
polygonal shapes are within the scope of the invention. As noted
above, the metal frame 60 also provides a convenient means of
connecting with the tabletop with the table legs.
[0029] FIG. 4 shows an embodiment of the invention, similar to FIG.
1. To construct this embodiment, a full layer of FRP 20 is placed
on a mold to construct the sheet that includes the shapes of the
cross-members 21 and rim 22. In this embodiment, this layer of FRP
sheet 20, along with the metal frame 60 and foam material 30,
constitute the supporting frame. Once the metal frame 60 is in
place within cross-members 21, it may be tacked to FRP layer 20
using rivets 215. Raw foam material 30 may then fill in the
U-shaped spaces within cross members 21 and rim 22. After the foam
material 30 is expanded, preferably constrained within a low
pressure press, for example, a second layer of FRP, or plastic
sheet 10, is placed over the entire supporting frame (i.e., which
bonds to the FRP layer 20). This forms the enclosed space
containing the metal frame 60 and the foam material 30. In this
embodiment, the plastic sheet 10 is not visible in FIG. 4 because
it is below the first layer of FRP 20 forming supporting frame.
Because the cross members 21 and rim 22 are all one piece with the
remaining layer of FRP 20, all are designated 20 (or parts thereof)
in the drawing. This is intentional to clarify this embodiment.
[0030] It is to be understood that the invention is not to be
limited to the exact configuration as illustrated and described
herein. Accordingly, all expedient modifications readily attainable
by one of ordinary skill in the art from the disclosure set forth
herein, or by routine experimentation therefrom, are deemed to be
within the spirit and scope of the invention as defined by the
appended claims.
* * * * *