Rod-reinforced cushion beam

Abstract

A rod-reinforced cushion beam includes a rigid frame having a spaced of main rod members and a longitudinally paced plurality of connecting elements; and a plastic body encapsulating substantially solidly filling the frame. At least some of the transverse elements are shear panels. A preferred embodiment has least 90 percent by weight of the plastic body in a main polymeric component of linear low density polyethylene, and an additive component that does not contain filler material. Also disclosed is a method for forming a rod-reinforced cushion beam.

1 . A composite beam comprising: 
 (a) a frame comprising: 
 (i) a plurality of longitudinal main rod members, at least three of the main rod members being spaced laterally in different corresponding directions relative to a longitudinal axis of the frame; and  
 (ii) 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, wherein at least some of the transverse elements are shear panels; and  
   (b) a resilient plastic body member encapsulating the frame, the plastic body having a nominal cross-sectional area of at least 50 square inches.    
   
   
       2 . The composite beam of  claim 1 , wherein the plastic body forms an elongate cushion surface, the beam having an overall thickness between the cushion surface and an opposite surface of the beam, the cushion surface being spaced from the frame by not less than 10 percent of the overall thickness.  
   
   
       3 . The composite beam of  claim 1 , 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.  
   
   
       4 . The composite beam of  claim 3 , wherein the first set of shear panels is connected between a first pair of the main rod members and the second set of shear panels is connected between a second pair of the main rod members.  
   
   
       5 . The composite beam of  claim 4 , wherein the plurality of main rod members includes respective third and fourth pairs of the main rod members, the first set of shear panels being further connected between the third pair of main rod members opposite the rod members of the first pair, the second set of shear panels being further connected between the fourth pair of main rod members opposite the rod members of the second pair.  
   
   
       6 . The composite beam of  claim 1 , 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.  
   
   
       7 . The composite beam of  claim 1 , 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.  
   
   
       8 . The composite beam of  claim 1 , 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.  
   
   
       9 . The composite beam of  claim 8 , 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.  
   
   
       10 . The composite beam of  claim 1 , wherein the main rod members have a nominal diameter of between approximately 2 percent and approximately 6 percent of a nominal outside circumference of the plastic body.  
   
   
       11 . The composite beam of  claim 10 , wherein the plastic body sealingly surrounds the cage frame, having a thickness over each of the main rod members and the transverse elements being not less than approximately 4 percent of the nominal outside circumference of the plastic body.  
   
   
       12 . The composite beam of  claim 10 , wherein the outside circumference of the plastic body is approximately 48 inches, and the diameter of the main rod members is approximately 1¼ inch.  
   
   
       13 . The composite beam of  claim 10 , wherein the plastic body is rectangular in cross-section.  
   
   
       14 . The composite beam of  claim 13 , wherein the plastic body is square in cross section.  
   
   
       15 . The composite beam of  claim 1 , wherein the plastic body substantially fills the space occupied by the frame.  
   
   
       16 . The composite beam of  claim 1 , wherein the plastic body consists of a main polymeric component and an additive component, the main polymeric component consisting of low-density polyethylene of which at least 60 percent is linear low density polyethylene, the additive component including an effective amount of an ultraviolet inhibitor.  
   
   
       17 . 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.  
   
   
       18 . An installed fender assembly comprising a plurality of composite beams according to  claim 1 .  
   
   
       19 . A method for forming a composite beam, comprising the steps of: 
 (a) providing a plurality of elongate main rod members;    (b) providing a plurality of transverse elements;    (c) rigidly securing opposite portions of each of the transverse elements between a laterally spaced pair of the main rod members such that at least three of the main rod members have pluralities of the transverse elements projecting therefrom in at least two directions having components perpendicular to the respective main rod members to form a cage frame,    wherein the step of rigidly securing is such that at least some of the transverse elements are shear panels so that the main rod members are strained primarily in tension and compression in response to bending and shear loading of the resulting cage truss; and    (d) encapsulating the cage frame in a plastic body.    
   
   
       20 . The method of  claim 19 , wherein at least some of the securing is by welding.  
   
   
       21 . The method of  claim 19 , wherein at least some of the securing is by forming joints of reinforced epoxy resin.  
   
   
       22 . A method for forming a composite beam, comprising the steps of: 
 (a) rigidly securing a spaced plurality of main rod members to opposite edge regions of a first longitudinally spaced array of shear panels to form a first frame portion;    (b) rigidly securing a spaced plurality of main rod members to opposite edge regions of a second longitudinally spaced array of shear panels to form a second frame portion;    (c) locating respective portions of the first and second frame portions in laterally spaced relation;    (d) rigidly securing a longitudinal array of transverse elements between the first and second frame portions to form a cage frame; and    (e) encapsulating the cage frame in a plastic body.    
   
   
       23 . The method of  claim 22 , wherein the step of encapsulating comprises: 
 (a) providing an injection mold having an elongate cylindrical cavity;    (b) loading the mold with the welded cage frame;    (c) centering the welded cage frame within the mold;    (d) injecting a polymeric composition into the mold thereby covering the cage frame; and    (e) cooling the mold to form the structural plastic member.    
   
   
       24 . The method of  claim 23 , wherein the injecting comprises formulating the polymeric composition to consist of low density polyethylene, at least 60 percent of the polymeric composition being linear low-density polyethylene.  
   
   
       25 . The method of  claim 22 , further comprising bonding a plurality of fastener attachments to the cage frame prior to the injecting.  
   
   
       26 . The composite beam of  claim 1 , wherein the shear panels comprise laterally spaced first and second shear panels, each panel having an extended length, being bonded between a pair of the main rod members, and having notches and/or openings therein for clearing outer and inner portions of the plastic body.  
   
   
       27 . The composite beam of  claim 26 , wherein the shear panels each extend substantially the full length of the cage frame.  
   
   
       28 . The composite beam of  claim 26 , wherein the first shear panel is connected between a first pair of the main rod members and the second shear panel is connected between a second pair of the main rod members.  
   
   
       29 . The composite beam of  claim 28 , wherein the plurality of main rod members includes respective third and fourth pairs of the main rod members, the first shear panel being further connected between the third pair of main rod members opposite the rod members of the first pair, the second shear panel being further connected between the fourth pair of main rod members opposite the rod members of the second pair.  
   
   
       30 . A composite beam comprising: 
 (a) a frame comprising: 
 (i) a plurality of longitudinal main rod members, at least three of the main rod members being spaced laterally in different corresponding directions relative to a longitudinal axis of the frame; and  
 (ii) 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, wherein at least some of the transverse elements are shear panels; and  
   (b) a resilient plastic body member encapsulating the frame.    
   
   
       32 . The composite beam of  claim 1 , wherein at least some of the shear panels have openings and/or notches formed therein.  
   
   
       33 . The composite beam of  claim 34 , wherein at least some of the shear panels have openings and/or notches formed therein.  
   
   
       34 . The composite beam of  claim 1 , wherein the shear panels comprise laterally spaced first and second shear panels, each panel having an extended length, being bonded between a pair of the main rod members, and having notches and/or openings therein.  
   
   
       35 . The composite beam of  claim 35 , wherein the shear panels comprise laterally spaced first and second shear panels, each panel having an extended length, being bonded between a pair of the main rod members, and having notches and/or openings therein.