Rod-reinforced cushion beam
A reinforced cushion beam includes a rigid frame having a plurality of interconnected elements; a plastic body encapsulating and substantially solidly filling the frame, and one or more panel members connected to the plastic body with a plurality of recessed fasteners that extend through the panel(s) and into the plastic body to form a scuff-resistant load-bearing surface. Also disclosed is a method for forming the cushion beam.
This application is a continuation-in-part of application Ser. No. 10/927,569 filed Aug. 25, 2004, which is a continuation-in-part of application Ser. No. 10/346,204, now U.S. Pat. No. ______, which is a continuation-in-part of application Ser. No. 10/278,754, filed on Oct. 22, 2002, now U.S. Pat. No. ______, each of these applications being incorporated herein by the respective references.
BACKGROUNDThe present invention relates to elongated structural members such as pilings, columns, wales, planks, and beams, particularly for used in marine environments, and methods for making such members.
Concrete, steel, and wood are conventionally used for pilings, telephone poles, beams and the like. However, each of these materials has disadvantages. Concrete and steel pilings are heavy and awkward to maneuver. Neither concrete nor steel pilings make good fender pilings because neither is “forgiving” when impacted. Under impact steel bends and buckles and concrete shatters. Both concrete and steel pilings are expensive to repair. Furthermore, steel, either standing alone or as a reinforcement in porous concrete, is subject to corrosion.
Wood pilings, planks, and beams are plagued by wear and tear and, particularly in marine environments such as in piers and ship moorings, are attacked by wood-boring marine organisms. Wood pilings, wales and planks are typically treated with creosote, but even this material can be ineffective against modern marine borers. These marine borers can only be stopped by wrapping the wood pilings in plastic coverings. However, these plastic coverings cannot withstand much wear and tear, especially abrasion from normal vessel contact. So in addition to a thin plastic wrap, wooden fender piles and planks often require thick plastic wrappings, which are expensive to put in place, being also subject to separation.
Composite pilings are also known, being disclosed for example in U.S. Pat. No. 5,180,531 to Borzakian, that document being incorporated herein by this reference. The '531 patent discloses a plastic pipe having an inner pipe core or mandrel being 6 inches or less in diameter, and a substantially homogenous coating being at least two inches thick. The thick plastic coating provides the bulk of the mechanical strength, being formulated with a desired combination of flexibility, brittleness, and impact resistance for use as pilings including fender pilings of docks, telephone poles, light standards, etc.
U.S. Pat. No. 5,766,711 to Barmakian, which is incorporated herein by this reference, discloses a composite camel structure including a pipe mandrel and a thermally bonded plastic cushion surrounding the mandrel. A mold having the mandrel centered therein is filled with molten plastic, the plastic being cooled and solidified by feeding water into the mandrel for progressively solidifying the cushion member along mandrel for producing a thermal bond without excessive tensile strain in the plastic material, thereby to achieve a substantially unbroken outside surface.
U.S. Pat. No. 6,244,014 to Barmakian, which is incorporated herein by this reference, discloses a composite piling having a welded cage including a circular array of parallel spaced main rod members that are welded about a helically formed secondary rod member, the cage being encapsulated in a plastic body.
U.S. Pat. No. 6,412,431 to Barmakian et al., which is also incorporated herein by this reference, discloses a composite fender having a cage frame encapsulated in a plastic body, the cage frame having an attachment structure connected to plural spaced apart locations of the frame.
Notwithstanding the above, it is believed that there is a need for further improvements in structural components to be used as beams in moorings, piers, and the like that are contemplated to be used in marine environments, that such components have high bending strength and high resistance to impact loading, and that they have long life, are easily installed, environmentally sound, and durable in use.
SUMMARYThe present invention meets this need by providing a reinforced cushion beam of high bending strength, being particularly suitable for a variety of marine applications. In one aspect of the invention, a composite beam having cross-sectional area of at least 50 square inches includes a frame having a plurality of interconnected members; a resilient plastic body member substantially encapsulating the frame; a panel member spaced from the frame, a portion of the resilient body filling space between the panel member and the frame, the panel member forming a load-bearing outside surface portion of the beam; and a spaced plurality of fasteners extending through the panel member in recessed relation thereto, through portions of the plastic body, and into engagement with the frame. Preferably the panel member includes a resilient material for cushioned contact with objects coming into contact with the beam. Preferably the panel member includes ultra-high molecular weight (UHMW) polymer for providing a desired combination of cushioning, strength and scuff resistance. More preferably the panel member substantially consists of the ultra-high molecular weight (UHMW) polymer. It is also preferred that the plastic body include a resilient material having a first rigidity, the material of the panel member having a second and greater rigidity for withstanding localized impact loading.
The composite beam can include an attachment structure defining a spaced plurality of attachment elements connected to plural spaced apart locations of the frame. Preferably the attachment structure includes a plurality of transverse members bonded at spaced locations along the frame, each of the transverse members having at least one receptacle for engagement by a corresponding one of the fasteners for facilitating spacing the threaded openings to match a predetermined spacing of the fasteners. The fasteners can be threaded fasteners such as cap screws, the receptacles being threaded openings.
The frame can include a plurality of longitudinal main rod members, at least three of the main rod members being spaced laterally in different corresponding directions relative to the longitudinal axis; and a plurality of transverse elements, each transverse element being rigidly connected between a spaced pair of the main rod members, at least three of the main rod members being connected to at least two others of the main rod members by at least some of the transverse elements. At least some of the transverse elements can be shear panels. The composite beam of claim 10, wherein the shear panels comprise laterally spaced first and second sets of longitudinally spaced shear panels, the panels of each set being bonded between a pair of the main rod members. Preferably at least some of the shear panels have openings and/or notches formed therein, the body member having portions external to the cage frame integrally joined through the openings and/or notches with portions of the body member within the frame for enhanced structural integrity of the body member.
Alternatively (or additionally) at least one pair of the main rod members is connected by some of the transverse elements being transverse rod segments such that diverging pairs of the transverse rod segments are connected in proximal relation at spaced intervals along each main rod member of the pair, whereby the pair of main rod members and the diverging pairs of transverse rod segments form a truss.
Preferably the main rod members and the transverse elements are each spaced at least 0.5 inch within an outside contour of the plastic body for enhanced cushioning and isolation of the frame from harmful contamination. The main rod members can be selected from the group consisting of formed steel reinforcing bars, formed nickel alloy reinforcing bars, fiberglass reinforcing bars, and carbon fiber reinforcing bars. The at least some of the transverse elements can be selected from the group consisting of formed steel reinforcing bars, formed nickel alloy reinforcing bars, fiberglass reinforcing bars, carbon fiber reinforcing bars, plastic dowels, wooden dowels, steel plates, and fiberglass panels.
A plurality of the composite beams can be assembled to form a fender assembly.
In another aspect of the invention, a method for forming a scuff-resistant composite beam includes the steps of: (a) providing a frame comprising a plurality of interconnected members; (b) encapsulating the frame in a plastic body; (c) providing a one or more scuff-resistant panel members; (d) providing a plurality of headed fasteners; and (e) connecting each of the one or more panel members to the plastic body with at least two of the fasteners projecting through each panel member in recessed relation thereto, and through portions of the plastic body to provide a scuff resistant load bearing surface on the resulting composite beam. The step of connecting can further include the steps of (i) affixing a plurality of attachment members at spaced locations along the frame; and (ii) engaging the fasteners with corresponding ones of the attachment members, thereby anchoring the one or more panel members to the frame. Preferably the step of affixing includes the further step of positioning the attachment members at sufficiently greater spacing along the frame to compensate for thermal extension of the frame at ambient temperature following the step of encapsulating.
DRAWINGSThese and other features, aspects, and advantages of the present invention will become better understood with reference to the following description, appended claims, and accompanying drawings, where:
The present invention provides a novel reinforced plastic cushion beam that is particularly effective as a sheathing plank, wale, or other structural element of a wharf facility. With reference to
As best shown in
The cage truss 12 includes a plurality of longitudinal main rod members 16 that are rigidly interconnected by transverse elements 17 that can include a multiplicity of transverse rod segments 18, opposite end portions of each segment 18 being connected between a pair of the main rod segments 16. As best shown in
In another aspect, the cage truss 12 includes a spaced pair of generally planar truss units 26 that are connected in generally parallel-spaced relation by the tie rod segments 24. In one preferred form, the cage truss 12 is a weldment of steel reinforcing bars having ribbed contours as indicated in
As shown in
An important feature of the present invention is a formulation of polymeric material that is suitable for encapsulating the cage truss 12 and that does not form voids and cracks due to tensile thermal strains being generated during solidification. This problem is exacerbated by the absence of a tubular mandrel that can receive cooling water as disclosed in the camel structure of the above-referenced '711 patent. It has been discovered that a particularly suitable composition for forming the plastic body 14 as an uninterrupted covering of the cage truss 12 is a main first quantity of low density polyethylene of which at least 60 percent and preferably 65 percent is linear low-density polyethylene (LLDPE), the balance being regular low-density polyethylene (LDPE), and a process additive second quantity including an effective amount of UV inhibitor, the composition not having any significant volume of filler material such as calcium carbonate. Preferably, the first quantity is at least 90 percent of the total volume of the plastic body 14, approximately 5 percent of the total volume being a mixture of coloring, foaming agent, and UV inhibitor. Preferably the composition is substantially free (not more than 5 percent) of high density polyethylene.
Thus the composition of the cushion member 14 has polymeric elements being preferably exclusively polyethylene as described above (substantially all being of low-density and mainly linear low-density), together with process additives as described below. As used herein, the term “process additive” means a substance for enhancing the properties of the polymeric elements, and does not include filler material such as calcium carbonate. The composition preferably contains a process additive which can be a foaming or blowing agent in an amount of up to about 0.9% by weight to insure than when the plastic body 14 is made by extruding the plastic composition into a mold, the mold is completely filled. The foaming agent can be a chemical blowing agent such as azodicarbonamide. A suitable chemical blowing agent is available from Uniroyal of Middlebury, Conn., under the trade name Celogen AZ 130.
Other process additives of the composition can include a coupling agent, preferably a silane, for improved bonding between the plastic body 14 and the cage truss 12.
The plastic composition can also include a fungicide, typically in an amount of about 0.25% by weight, and an emulsifier, in an amount of from about 0.1% to 0.3% by weight. The use of emulsifier improves surface appearance of the product.
The composition can also contain a carbon black, generally a furnace black, as a colorant, to improve the physical properties, and as a UV stabilizer. The amount of carbon black used is generally about 2.5% by weight.
A mold apparatus (not shown) for encapsulating the cage truss 12 to form the plastic body 14 of the cushion beam 10 includes a mold assembly and a conventional extruder press, including one or more flanged tubular mold segments as further described in the above-referenced '014 patent, but with the cross-sectional shape of the mold segments conforming to the cross-sectional shape of the body 14, with appropriate allowances for shrinkage as further described in the '014 patent.
As further described in the '014 patent, the cage truss 12 centered within a main cavity of the mold assembly, being supported by a plurality of projections 20, and/or by fasteners temporarily engaging one or more of the fastener attachments 30, or by centering screws as disclosed in the above-referenced '711 patent. Alternative mold construction is also described in the above-referenced '431 patent.
With further reference to
Next, the material of the plastic body 14 is fed into the main cavity in an inject body step 110. Then in a cooling step 112, the mold assembly with its contents is submerged in cooling water for solidifying the material of the plastic body 14, after which the assembly 42 is removed from the water (step 114), the mold is opened (step 116), and the substantially complete cushion beam 10 is withdrawn (step 118). Further details of this process are described in the above-referenced '014 and '431 patents.
With further reference to
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In some military based naval applications, it is undesirable for a marine-exposed structure to be electro-magnetically sensitive. In such applications the cage truss 12 can be formed with non-magnetic materials, such as nickel reinforcing bar (formed of a corrosion-resistant steel alloy), which is available from MMFX Steel Corp. of America, Charlotte, N.C. Another suitable material is carbon-reinforced plastic bar, available from Aero Space Composite Products of San Leandro, Calif. The cage truss 12 can also be developed by using fiberglass reinforcing rods, with reinforced epoxy joints at points of contact between the main rods 12 and the various transverse rod segments 18 and/or diagonal rod segments 20. Additional suitable materials include Nylon Reinforcement, available from McMasters Co. of Los Angeles, Calif., plastic dowels, also available from McMasters, and wooden dowels, which are available from typical lumber yards.
With further reference to
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In the exemplary configuration of
With particular reference to
With particular reference to
With further reference to
While threaded fasteners had been considered for joining the panel members 70 to the frame, an additional problem is that the molding process alters the spacing between different locations of the frame. More particularly, if threaded studs are welded to specific locations on the frame to match a hole spacing of the panel members, there will be significant initial expansion of the frame when the encapsulating plastic is introduced at approximately 450° F. As the plastic cools and hardens at about 350° F. the steel is still significantly extended, causing compressive forces within the plastic body as the combination cools to ambient. As a result, the frame remains somewhat extended, even at ambient temperatures.
It has been discovered that a particularly suitable means for affixing the panel members 70 to the plastic body 14 is a plurality of headed fasteners 72 that directly engage the cage frame 62′″. More particularly, and as best shown in
As further shown in
The cage frame 62′″ also includes counterparts of the shear panels 64A and 64B of
The cushion beam 10 (as well as the alternatively configured beams 10′, 10″, 60, 60′, and 60″) of the present invention is immune to marine borer attack, and thus requires no further protection, such as creosote or plastic sheathing, being practically maintenance free. The cushion beam 10 is abrasion resistant, and thus has excellent effectiveness as a marine fender plank without any added protective covering.
The composite cushion beam 10 is chemically inert, so it can last indefinitely. It does not react with sea water, is corrosion free, is substantially immune to the effects of light, is not bothered by most petroleum products, and is not subject to dry rot. Because it can be made with recycled plastic, it is an environmentally sound investment.
Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions are possible. For example, the main rods 16 can be formed having a flattened or elongate cross-section that is preferably oriented to facilitate forming the connections with the transverse rod elements 18. Also, the one or more panel members 70 can be concentrated at one end of the cushion beam 60 for use of the beam as a cushioned piling. Therefore, the spirit and scope of the appended claims should not necessarily be limited to the description of the preferred versions contained herein.
Claims
1. A composite beam having a longitudinal axis and a cross-sectional area of at least 50 square inches, comprising:
- (a) a frame comprising a plurality of interconnected members;
- (b) a resilient plastic body member substantially encapsulating the frame;
- (c) a panel member spaced from the frame, a portion of the resilient body filling space between the panel member and the frame, the panel member forming a load-bearing outside surface portion of the beam; and
- (d) a spaced plurality of fasteners extending through the panel member in recessed relation thereto, through portions of the plastic body, and into engagement with the frame.
2. The composite beam of claim 1, wherein the panel member comprises a resilient material.
3. The composite beam of claim 2, wherein the panel member comprises ultra-high molecular weight (UHMW) polymer.
4. The composite beam of claim 2, wherein the panel member substantially consists of an ultra-high molecular weight (UHMW) polymer.
5. The composite beam of claim 2, wherein the plastic body comprises a resilient material having a first rigidity, the material of the panel member having a second rigidity being greater than the first rigidity.
6. The composite beam of claim 1, further comprising an attachment structure defining a spaced plurality of attachment elements connected to plural spaced apart locations of the frame.
7. The composite beam of claim 6, wherein the attachment structure comprises a plurality of transverse members bonded at spaced locations along the frame, each of the transverse members having at least one receptacle for engagement by a corresponding one of the fasteners.
8. The composite beam of claim 7, wherein at least some of the fasteners are threaded fasteners, the receptacles being threaded openings.
9. The composite beam of claim 1, wherein the frame comprises:
- (a) a plurality of longitudinal main rod members, at least three of the main rod members being spaced laterally in different corresponding directions relative to the longitudinal axis; and
- (b) a plurality of transverse elements, each transverse element being rigidly connected between a spaced pair of the main rod members, at least three of the main rod members being connected to at least two others of the main rod members by at least some of the transverse elements.
10. The composite beam of claim 9, wherein at least some of the transverse elements are shear panels.
11. The composite beam of claim 10, wherein the shear panels comprise laterally spaced first and second sets of longitudinally spaced shear panels, the panels of each set being bonded between a pair of the main rod members.
12. The composite beam of claim 10, wherein at least some of the shear panels have openings and/or notches formed therein, the body member having portions external to the cage frame integrally joined through the openings and/or notches with portions of the body member within the frame for enhanced structural integrity of the body member.
13. The composite beam of claim 9, wherein at least one pair of the main rod members is connected by some of the transverse elements being transverse rod segments such that diverging pairs of the transverse rod segments are connected in proximal relation at spaced intervals along each main rod member of the pair, whereby the pair of main rod members and the diverging pairs of transverse rod segments form a truss.
14. The composite beam of claim 9, wherein the main rod members and the transverse elements are each spaced at least 0.5 inch within an outside contour of the plastic body.
15. The composite beam of claim 9, wherein the main rod members are selected from the group consisting of formed steel reinforcing bars, formed nickel alloy reinforcing bars, fiberglass reinforcing bars, and carbon fiber reinforcing bars.
16. The composite beam of claim 15, wherein at least some of the transverse elements are selected from the group consisting of formed steel reinforcing bars, formed nickel alloy reinforcing bars, fiberglass reinforcing bars, carbon fiber reinforcing bars, plastic dowels, wooden dowels, steel plates, and fiberglass panels.
17. An installed fender assembly comprising a plurality of composite beams according to claim 1.
18. A method for forming a scuff-resistant composite beam, comprising the steps of:
- (a) providing a frame comprising a plurality of interconnected members;
- (b) encapsulating the frame in a plastic body;
- (c) providing a one or more scuff-resistant panel members;
- (d) providing a plurality of headed fasteners; and
- (e) connecting each of the one or more panel members to the plastic body with at least two of the fasteners projecting through each panel member in recessed relation thereto, and through portions of the plastic body to provide a scuff resistant load bearing surface on the resulting composite beam.
19. The method of claim 18, wherein the step of connecting further comprises the steps of:
- (i) affixing a plurality of attachment members at spaced locations along the frame; and
- (ii) engaging the fasteners with corresponding ones of the attachment members, thereby anchoring the one or more panel members to the frame.
20. The method of claim 19, wherein the step of affixing further comprises the step of positioning the attachment members at sufficiently greater spacing along the frame to compensate for thermal extension of the frame at ambient temperature following the step of encapsulating.
Type: Application
Filed: Nov 22, 2004
Publication Date: May 26, 2005
Inventor: Andrew Barmakian (Rialto, CA)
Application Number: 10/997,025