COMPOSITE PANEL AND METHOD FOR FORMING THE SAME

Apparatus and methods directed to a panel for use on a trailer. The panel includes a panel member core with a length that can have a first segment of thermoplastic foam extending the length and a second segment of thermoplastic foam extending the length adjacent the first segment. The first segment can have a first density and the second segment can have a second density. The first density can be greater than the second density. A sheet can extend over the first and second segments and can be laminated to the panel member core. The panel member can be formed through extrusion.

BACKGROUND

Many storage containers, such as mobile storage containers for box or van-type trailers, include side walls and a roof assembly formed by multiple panel members coupled together. The panel members can be made from various types of materials in different configurations.

SUMMARY

Some embodiments of the invention can provide a panel for use on a trailer. The panel can include a panel member core with a length and can including a first segment of thermoplastic foam extending the length and a second segment of thermoplastic foam extending the length adjacent the first segment. The first segment can have a first density and the second segment can have a second density. The first density can be greater than the second density. A sheet can extend over the first and second segments and a can be laminated to the panel member core. The panel member core can be formed by extrusion.

Other embodiments of the invention can provide a method of forming a panel for use on a trailer. The method can include extruding a panel member core of thermoplastic foam with a first region that can have a first density and a second region, adjacent the first region, that can have a second density. The second density can be less than the first density. The panel member core can be cut at a predetermined length. A sheet can extend over the first and second regions and can be laminated to the panel member core.

Other embodiments of the invention can provide a method for forming a panel member core with a length for a panel that can be used in a trailer. The method can include extruding a first region, a second region, a third region, a fourth region, and a fifth to extend along the length in parallel. The first, third, and fifth region can be configured to have a greater density than the second region and the fourth region. The extruded first, second, third, fourth, and fifth regions can be cut to the length.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles of the invention, reference will now be made to illustrative embodiments shown in the attached drawings and specific language will be used to describe the same. Some of the discussion below describes a laminated panel member core that can be sandwiched between sheets formed from metal, plastic, reinforced plastic, or high modulus materials such as carbon fiber or aramid fiber. The context and particulars of this discussion are presented as examples only. For example, embodiments of the disclosed invention can be configured in various ways, including with other shapes and arrangements of elements. Similarly, while the concepts of this disclosure are described in relation to a truck trailer, it will be understood that they are equally applicable to other mobile or stationary storage enclosures or containers, as well as refrigerated and un-refrigerated trailers, storage containers, or truck bodies that include wall and/or roof panels joined together.

As used herein, directional terms including “top,” “bottom,” “side,” “horizontal,” “vertical,” and so on are used to indicate directional relationships with respect to an arbitrary reference frame (e.g., a reference frame of a particular figure or figures). These directional terms are used consistently relative to a particular embodiment. For example, a “top” feature of an embodiment is opposite a corresponding “bottom” feature, and a “horizontal” feature generally extends perpendicularly to a “vertical” feature. However, unless otherwise defined or limited, these directional terms are not intended to indicate an absolute reference frame for a particular assembly.

In conventional arrangements, panel members can be made from various types of materials in different configurations. For example, panel members can be made with hexagonal honeycomb cores that have a uniform internal structure and in which the axis of each honeycomb cell extends perpendicular to the length and width of the adjacent sheets. Cargo securement elements or fasteners must therefore be located in areas at or near the seams of adjacent panels where additional overlapping material is provided. Another example includes panel members comprising a core partially formed from a foamed thermoplastic and include higher density foam blocks inserted manually in locations in areas needing additional structural support. Although these conventional arrangements of panels can provide adequate structural strength and support for fasteners, mounting and fastening options for cargo securement elements and fasteners are limited and labor can be fairly intensive to manufacture the panel members.

Embodiments of the invention can address these or other issues. For example, in some embodiments, a panel member core can include areas of different densities. Some areas may be formed with higher density foam, respectively, for securing mounting elements or fasteners thereto, while other areas may be formed with lower density foam to reduce the overall weight of the panel member. As another example, other regions within the panel core can have densities between the densities of the higher and lower density regions. An example of the process for making a panel member core can include the extrusion and combination of streams of thermoplastic foam having the same or different densities. In some examples, the thermoplastic can be high density polyethylene (HDPE) or polypropylene (PP).

As shown inFIG. 1, a trailer10can comprise a plurality of interconnected panel members12. As shown inFIG. 2, each of the panel members12can be formed by laminating sheets14, or skins, to a panel member core16.

FIG. 3illustrates a first example of a method of forming a panel member core116(FIG. 4) according to an embodiment of the invention. A first extruder120extrudes a first set of streams (a first stream122, a third stream124, and a fifth stream126) of a thermoplastic foam all having a first thickness128. A second extruder130extrudes a second set of streams (a second stream132and a fourth stream134) of a thermoplastic foam all having a second thickness136. The first thickness128is substantially equal to the second thickness136. The first extruder120and the second extruder130can extrude at the same lineal feet per minute rate.

The first, third, and fifth streams122,124,126each have a first density, and the second and fourth streams132,134each have a second density. In the example, the first density of the first, third, and fifth streams122,124,126extruded from the first extruder120can be greater than the second density of the second and fourth streams132,134extruded from the second extruder130. For example, the first density can be in the range of about 14 lb/ft3to about 30 lb/ft3and the second density can be in the range of about 1 lb/ft3to about 13 lb/ft3. The streams122,124,126,132,134can be thermally welded together to form a single continuous panel member core stream118, which can be cut to a predetermined dimension to form the panel member core116(FIG. 4). The first, third, and fifth streams122,124,126define a first, third, and fifth segment150,152,154, respectively, and the second and fourth streams132,134define a second and fourth segment156,158, respectively, in the panel member core116. The segments150,152,154,156,158extend parallel with each other along the length144of the panel member core116. When installed on the trailer10, each of the segments150,152,154,156,158extends from the top of the trailer10to the bottom.

The first, third, and fifth segments150,152,154are shown with widths that are smaller than the widths of the second and fourth segments156,158. However, other configurations with segments of different widths are contemplated, including the inverse of the panel member core116, and the figures should not be viewed as limiting.

In other embodiments, other configurations are possible. For example, more or fewer alternating extrusion streams of different or similar densities can be combined to form a panel member core as determined by the predetermined structural and weight requirements. For example, in some embodiments, the first, third, and fifth streams122,124,126can each have a different density. In some embodiments, two of the first, third, and fifth streams122,124,126can have the same density and the other of the first, third, and fifth streams122,124,126can have a lesser or a greater density. In some other embodiments, the densities of the second and fourth streams132,134can be different. In some embodiments, at least two of the densities of the first, second, third, fourth, and fifth streams122,132,124,134,126can be the same.

A weld zone138can be formed between any two adjacent, thermally welded extrusion streams, for example, between the second stream132and the third stream124shown inFIG. 3. The weld zone138can be formed during the thermal welding process to create a non-porous solid wall of homogenous plastic extending the length144and thickness128,136of the panel member core stream118between the two extrusion streams132,124. The weld zone138can increase the compressive strength of the panel member core116, making it more resistant to compressive loads. The compressive strength of the panel member core116can be further aided by the foam of the streams132,124provided on either side of the weld zone138further resisting deflection.

FIGS. 5, 5A, and 5Billustrate another example of a method of forming a panel member core216(FIG. 6) according to another embodiment of the invention. An extruder220extrudes a continuous panel member core extrusion42having a first set of regions240(a first region222, a third region224, and a fifth region226) and a second set of regions242(a second region232and a fourth region234). The continuous panel member core extrusion218can have a density in a range from about 1 lb/ft3to about 25 lb/ft3. The first, third, and fifth regions222,224,226are extruded at a first thickness228and the second and fourth232,234are extruded at a second thickness236(FIG. 4A). The first thickness228is greater than the second thickness236. For example, the first thickness can be about 1 inch and the second thickness can be about ½ inch. In other embodiments, other configurations are possible. For example, more or fewer regions of different or similar thicknesses can be combined to form a panel member core as determined by the predetermined structural and weight requirements. For example, in some embodiments, the thicknesses of the first, third, and fifth regions222,224,226can each have a different thickness. In some embodiments, two of the first, third, and fifth regions222,224,226can have the same thickness and the other of the first, third, and fifth regions222,224,226can have a smaller or a greater thickness. In some other embodiments, the thicknesses of the second and fourth regions232,234can be different. In some embodiments, at least two of the thicknesses of the first, second, third, fourth, and fifth streams222,232,224,234,226can be the same.

At least the first set of regions240of the panel member core stream218can be compressed to a third thickness238(FIG. 5B). The third thickness238can be equal to the second thickness236to form a panel member core stream218of uniform thickness. It is also contemplated that the second set of regions242can also be compressed at the same time as the first set of regions240to provide a uniform thickness of the panel member core stream218. Continuing with the example of the first and second thicknesses228,236above, the third thickness238can be in the range of about 7/16 inch to about ½ inch. InFIG. 5, for example, a set of rollers260are shown performing the compression of the panel member core stream218.

The compression of the first, third, and fifth regions222,224,226and the second and fourth regions232,234to the third thickness238increases the density of the first, third, and fifth regions222,224,226relative to the second and fourth regions232,234. In the example provided, the density of the first, third, and fifth regions222,224,226is approximately double the density of the second and fourth regions232,234because the first, third, and fifth regions222,224,226were about twice the thickness of the second and fourth regions232,234in the panel member core extrusion218and were compressed to the same thickness of the second and fourth regions232,234in the panel member core stream218.

After compression, the first, third, and fifth regions222,224,226can have a first density and the second and fourth regions232,234can have a second density. The first density can be in the range of about 14 lb/ft3to about 30 lb/ft3and the second density can be in the range of about 1 lb/ft3to about 13 lb/ft3. The panel member core stream can be cut to a predetermined dimension to form the panel member core216(FIG. 6).

Similar to the example method of forming the panel member core116described above, the panel member core stream218can be cut to a predetermined dimension to form the panel member core216(FIG. 6). The first, third, and fifth regions222,224,226can define first, third, and fifth segments250,252,254, respectively, and the second and fourth regions232,234can define second and fourth segments256,258, respectively, in the panel member core216. The segments250,252,254,256,258extend parallel with each other along the length244of the panel member core216. When installed on the trailer10, each of the segments250,252,254,256,258extends from the top of the trailer10to the bottom.

The first, third, and fifth segments250,252,254are shown with widths that are smaller than the widths of the second and fourth segments256,258. However, other configurations with segments of different widths are contemplated, including the inverse of the panel member core216, and the figures should not be viewed as limiting.

In other embodiments, other configurations are possible. For example, more or fewer alternating extrusion stream regions of different thicknesses and different or similar densities can be formed to provide a panel member core216as determined by the predetermined structural and weight requirements.

FIG. 7illustrates an example of a method of forming a panel member312according to an embodiment of the invention. An extruder forms a panel member core316having a first thickness328and a first density, both of which are uniform throughout the panel member core316. A sheet314is laminated to one or both sides of the panel member core316. The example inFIG. 7shows a sheet314laminated to both sides of the panel member core316. The combination of the sheets314and the panel member core316is then processed, wherein at least one predetermined area along the length344of the panel member312is designated to have a higher density. The predetermined area is heated locally with heaters364and compressed to a second thickness336, which is less than the first thickness328, to from the panel member312, wherein the compressed area has a greater density than the non-compressed area. As shown, the compression may be performed by rollers366along the sides of the panel member312. Excess material362may be trimmed with a trimming apparatus368as needed. Similar density values as provided above with respect to the other methods of forming a panel member core may be achieved in the regions having the first thickness328and the second thickness336. It should be noted that in some embodiments additional or fewer areas of compression are contemplated. For example, one of the rollers366can be removed or at least one additional roller can be added. In some embodiments, a panel member can have another area with a thickness different than the first and second thicknesses328,336. For example, the rollers366can be configured to compress the panel member to different thicknesses (e.g., by using rollers of different diameters). In another example, another roller configured to compress the panel member to a third thickness can be added.

Thus, the above-described methods for forming panel member cores can form panel member cores having different strength and weight characteristics. Areas within the panel member cores having a greater density can provide additional strength to reduce fastener tear out where hardware is bonded thereto or where panels are joined together. Areas within the panel member cores having a lower density, respectively, can reduce overall panel weight in areas in which additional strength is not required.

While the invention has been illustrated and described in detail in the foregoing drawings and description, the same is to be considered as illustrative and not restrictive in character, it being understood that only illustrative embodiments thereof have been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected. Furthermore, it will be understood that the embodiments discussed above are presented as examples only, and that other embodiments are possible. Moreover, it is intended and will be appreciated that embodiments may be variously combined or separated without parting from the invention. For example, it will be appreciated that all preferred features described herein are applicable to all aspects of the invention described herein.