Abstract:
A flexible buoy assembly includes a flexible buoy having a passage formed therethrough. A flexible line passes through the passage and exits each end thereof. First and second bumpers are fixedly coupled to the flexible line about the circumference thereof. The first bumper is spaced apart from the first end of the passage and the second bumper is spaced apart from the second end of the passage.

Description:
ORIGIN OF THE INVENTION 
     The invention described herein was made in the performance of official duties by an employee of the Department of the Navy and may be manufactured, used, licensed by or for the Government for any governmental purpose without payment of any royalties thereon. 
    
    
     FIELD OF THE INVENTION 
     The invention relates generally to buoys, and more particularly to a flexible buoy assembly that can flex as it is passed over rollers or other solid objects. 
     BACKGROUND OF THE INVENTION 
     Buoys are used for a variety of flotation applications. For example, buoys can be incorporated into towed cable assemblies that must be passed over rollers or other solid objects when they are deployed or retrieved. Accordingly, buoys in these applications are generally made of a flexible material with a cable being attached thereto on at least one end of the buoy. 
     Existing flexible buoys provide for attachment of a cable using one of the following three methods. In accordance with the first method, the cable is attached to an eye that is molded to or integrated with the buoy material so that cable tension essentially must be restrained by the flexible buoy material. This method is thus limited by the tear resistance of the flexible buoy material. 
     In accordance with the second method, the cable is attached to a rigid restraint that is passed through and coupled to the buoy body. While the rigid restraint is capable of withstanding substantial cable tension loads, the overall assembly is not flexible. 
     In accordance with the third method, a rigid tube is inserted through the buoy body and is held in place by friction with the surrounding buoy body. A flexible restraint is passed through or attached to the rigid tube. However, while the flexible restraint provides flexibility, the buoy body assembly (i.e., the buoy body with the rigid tube therein) is inflexible. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a flexible buoy assembly. 
     Another object of the present invention is to provide a flexible buoy assembly that is designed to experience minimal damage when passed over rollers or other solid objects. 
     Other objects and advantages of the present invention will become more obvious hereinafter in the specification and drawings. 
     In accordance with the present invention, a flexible buoy assembly includes a flexible buoy having a passage formed therethrough with first and second ends of the passage being defined. A flexible line passes through the passage and exits each of the first and second ends. First and second bumpers are fixedly coupled to the flexible line about the circumference thereof. The first bumper is spaced apart from the first end of the passage and the second bumper is spaced apart from the second end of the passage. 
     When the buoy assembly is pulled past a solid or rigid object, an angle is formed between the line exiting either end of the passage and that portion of the line passing through the passage. Once certain angles have been attained on either end of the buoy, the bumpers bear against the outer surface the buoy. Interacting bearing and tangential contact between the bumpers and the buoy provide resistance to tangential and axial tear out of the line from the buoy. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects, features and advantages of the present invention will become apparent upon reference to the following description of the preferred embodiments and to the drawings, wherein corresponding reference characters indicate corresponding parts throughout the several views of the drawings an wherein: 
     FIG. 1 is a cross-sectional view of an embodiment of a flexible buoy assembly in accordance with the present invention; 
     FIG. 2 is a cross-sectional view of another embodiment of a flexible buoy assembly in accordance with the present invention that includes a flexible linear encasing the line passing through the buoy body, the use of bearing plates, and the use of the bumpers to create attachment loops in the line after it exits the buoy body; and 
     FIG. 3 is a side view of the flexible buoy assembly illustrated in FIG. 1 as it undergoes movement over a solid object. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, and more particularly to FIG. 1, a flexible buoy assembly according to an embodiment of the present invention is shown and referenced generally by numeral  10 . Buoy assembly  10  can be used in a variety of applications to include, in the illustrated example, a flotation device forming part of a towed or otherwise tensioned cable assembly. However, it is to be understood that the inventive features of the present invention could also be incorporated into a stand alone flotation device or a boat bumper in which case a line would only be coupled to one end of the buoy body. 
     In the illustrated embodiment, buoy assembly  10  includes a flexible buoy body  12  having an internal longitudinal passage  14  formed therethrough. Typically, buoy body  12  is a hollow body made from a flexible plastic material so that its outer surface  12 A can flex inward when bumping into a solid object. As is known in the art, such buoy bodies can be inflated or molded to form the ultimate shape thereof. The particular geometrical configuration of buoy body  12  is not a limitation of the present invention. 
     Passing through and exiting passage  14  from either end thereof is a flexible line (e.g., metal or composite cable, rope, etc.)  16 . Line  16  can be loosely fit in passage  14 , friction fit in passage  14 , or fixedly coupled to buoy body  12  along passage  14  using, for example, an adhesive (not shown). 
     Coupled to line  16  at either side of buoy body  12  are bumpers  18  and  20  with line  16  then extending beyond bumpers  18  and  20 . More specifically, bumper  18  is fixedly coupled (e.g., crimped onto, glued, etc.) to line  16  a distance h 1  from one end of passage  14  while bumper  20  is fixedly coupled to line  16  a distance h 2  from the opposite end of passage  14 . As will become more evident later herein, the distances h 1  and h 2  can be the same or different depending on the needs of a particular application. Each of bumpers  18  and  20  can be made from a solid (as shown) or hollow semi-rigid to rigid material such as metal, a composite or a plastic. 
     Bumpers  18  and  20  have respective surfaces  18 A and  20 A opposing buoy body  12 . The geometrical shape of each of surfaces  18 A and  20 A is typically circular so that the overall shape of bumpers  18  and  20  is generally cylindrical. However, the overall shape of bumpers  18  and  20  is not a limitation of the present invention. As will become more evident later herein, the diameters d 1 , and d 2  of surface areas  18 A and  20 A, respectively, can be the same or different depending on the particular application. 
     Another embodiment of the flexible buoy assembly in accordance with the present invention is illustrated in FIG.  2  and referenced generally by numeral  100 . The same reference numerals are used in FIG. 2 to indicate those elements that are common with the FIG. 1 embodiment. In buoy assembly  100 , line  16  is encased by, or passed through and fixed to, a flexible liner material  30 , the thickness and/or stiffness of which can be used to tailor the flexibility of the combination of line  16 /material  30 . Liner material  30  can be friction fit or attached to buoy body  12  along passage  14 . 
     Buoy assembly  100  further has line  16  forming one or more loops (e.g., loops  32  and  34  are illustrated) at either side of buoy body  12 . For example, line  16  is formed into loop  32  with ends  32 A and  32 B thereof being retained or captured (e.,g., by crimping, glue, etc.) by bumper  18 . A similar construction is used for loop  34 . Each of loops  32  an  34  can be coated with a flexible or protective material (not shown) to suit a particular application. 
     Buoy assembly  100  could also include rigid bearing plates or washers  36  and  38  disposed about line  16  between buoy body  12  and bumpers  18  and  20 , respectively. Bearing plates  36  and  38  can be loosely fit onto line  16  and serve as respective bearing surface for bumpers  18  and  20  during the bending or curving of line  16  as will be explained further below. Either or both of bearing plates  36  and  38  can be replaced with a stack of bearing plates (i.e., more than one) without departing from the scope of the present invention. 
     Operation of the present invention will now be explained for buoy assembly  10  with the aid of FIG. 3 where buoy assembly  10  is pulled past a solid or rigid object  200  which could be an obstruction, the edge of a ship&#39;s deck, rollers of a winching system, etc. In FIG. 3, a pulling force F P  is applied to line  16  above bumper  18  while a load force F L  is acting on line  16  below bumper  20 . The presence of object  200  causes an angular relationship between forces F P  and F L  so that line  16  above buoy body  12  forms an angle with line  16  passing through passage  14 . At a specific angle α 1  (which is determined by spacing h 1  and diameter d 1  ), bumper  18  begins to bear against outer surface  12 A of buoy body  12  and apply a bearing force F B1 , that is opposed by a force F B2  exerted by surface  12 A. A tangential force F T1  associated with forces F B1  and F  B2  is opposed by a tangential (frictional) force F T2  exerted by surface  12 A. By providing tangential force F T1 , the present invention provides resistance to the tangential tearing of line  16  from buoy body  12 . Axial tear out of line  16  is prevented by the interaction of bearing forces F B1 , and F B2 . 
     Similarly, line  16  below buoy body  12  forms an angle with line  16  passing through passage  14 . At a specific α 2  (which is determined by spacing h 2  and diameter d 2 ), bumper  20  begins to bear against outer surface  12 A so that bearing and tangential forces (similar to those described above) operate to prevent both axial and tangential tear out of line  16  from the lower end of buoy body  12 . The spacing h 2  and diameter d 2  can be selected to suit a particular application. It is to be understood that a similar operational description applies to buoy assembly  100  except that bumpers  18  and  20  would contact respective bearing plates  36  and  38  (once the critical angles α 1 , and α 2 , respectively, are attained) thereby distributing the bearing forces to outer surface  12 A through bearing plates  36  and  38 . 
     The advantages of the present invention are numerous. The entire buoy assembly is flexible thereby making it especially useful in towed cable applications. The use of an optional flexible liner encasing the line provides a means to tailor line flexibility in the buoy itself, provides additional bearing support along the buoy&#39;s internal passage, and prevents abrasion between the line and the buoy&#39;s internal passage. The bumpers introduce bearing and tangential forces that act to prevent tangential and axial tear out of the line from the buoy body. 
     Although the invention has been described relative to a specific embodiment thereof, there are numerous variations and modifications that will be readily apparent to those skilled in the art in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described.