US20070227416A1

US20070227416A1 - Tabletop for outdoor use reinforced with foam material and metal frame

Info

Publication number: US20070227416A1
Application number: US11/731,560
Authority: US
Inventors: Oliver Wang
Original assignee: Oliver Wang
Current assignee: AGIO INTERNATIONAL COMPANY Ltd
Priority date: 2004-10-19
Filing date: 2007-03-30
Publication date: 2007-10-04

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.

Description

CROSS-REFERENCE TO RELATED APPLICATION

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

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

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.
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.
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.
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.
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

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.
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.
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

The invention will be better understood in relation to the attached drawings illustrating preferred embodiments, wherein:
FIG. 1 is a perspective view of a tabletop of the present invention;
FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1;
FIG. 3 is a cross-sectional view of an alternate embodiment according to the invention; and
FIG. 4 is a perspective view of an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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.
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.
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.
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.
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.
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/m³to 1.2 kg/m³, 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.
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.
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.
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° 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° 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.
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.
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.
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.
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.
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.
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.

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

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.