Abstract:
A bitt with a freely rotatable line-handling surface includes a frame having a first side and a second side. The first and second sides of the frame each include first and second ends, and the first and second sides of the frame are substantially planar. The first and second sides adjoin each other at the first ends and define an angle therebetween. The first and second sides of the frame are arranged for being attachable to a surface of a marine vessel at the second ends of the first and second sides of the frame. First and second shafts extend outwardly from the planes of the first and second sides of the frame, respectively. The first and second shafts each have a longitudinal axis. The axis of each of the first and second shafts extends approximately perpendicularly to the plane of the first and second sides of the frame. First and second rollers each have an axis, and the first and second rollers each define a bore along the axis of the respective roller. The bores of the first and second rollers are each arranged for receiving the first and second shafts therethrough. The first and second rollers are rotatably mounted about the first and second shafts such that the first and second rollers provide freely rotatable line-handling surfaces.

Description:
FIELD OF THE INVENTION 
     This invention relates generally to marine deck equipment, and specifically to bitts. 
     BACKGROUND OF THE INVENTION 
     The use of marine deck equipment is well known for securing marine vessels to piers with mooring lines. In particular, bitts are used by line handlers to help the line handlers pull a marine vessel alongside a pier and secure the marine vessel to the pier. After a marine vessel is pulled alongside the pier, the line handler takes several round turns of the line around the bitt, thus securing the marine vessel alongside the pier. 
     Conventional bitts, however, present drawbacks. For example, when drawing a marine vessel alongside a pier, the line handler must be positioned in a bent-over body position instead of an erect body position. This limits the amount of the line handler&#39;s strength available for line-handling activities. In addition, a bent-over body position increases likelihood of back injury from line-handling activities. Further, a bent-over body position causes the hands of the line handler to be closer to the bitt than would an erect position, thus increasing likelihood of hand injury. Finally, a bent-over body position limits mobility of a line handler and reduces a line handler&#39;s situation awareness during potentially dangerous line-handling evolutions. 
     Conventional bitts include a static, non-movable line-handling surface. Friction between the mooring line and the line-handling surface of the bitt results in a significant amount of the line handler&#39;s energy being spent in overcoming friction. As a result, a significant portion of energy expended by the line handler is not translated into useful work, such as drawing the marine vessel alongside the pier. 
     Thus, there is an unmet need in the art for a bitt that permits a line handler to perform line-handling operations in an erect body position instead of a bent-over body position, and that permits much of the line handler&#39;s energy to be available for useful work in line-handling activities instead of being used to overcome friction. 
     SUMMARY OF THE INVENTION 
     The present invention is a bitt with a freely rotatable line-handling surface. The bitt of the present invention permits a line handler to perform line-handling activities in an erect body position instead of a bent-over body position. Further, the freely rotatable line-handling surface included in the bitt of the present invention allows much of the line handler&#39;s energy to be applied to useful work in drawing a marine vessel alongside a pier, instead of being wasted in overcoming line friction. 
     According to the present invention, a bitt includes a frame having a first side and a second side. The first and second sides of the frame each include first and second ends, and the first and second sides of the frame are substantially planar. The first and second sides adjoin each other at the first ends and define an angle therebetween. The first and second sides of the frame are arranged for being attachable to a surface of a marine vessel at the second ends of the first and second sides of the frame. First and second shafts extend outwardly from the planes of the first and second sides of the frame, respectively. The first and second shafts each have a longitudinal axis. The axis of each of the first and second shafts extends approximately perpendicularly to the plane of the first and second sides of the frame. First and second rollers each have an axis, and the first and second rollers each define a bore along the axis of the respective roller. The bores of the first and second rollers are each arranged for receiving the first and second shafts therethrough. The first and second rollers are rotatably mounted about the first and second shafts, such that the first and second rollers provide freely rotatable line-handling surfaces. 
     According to an aspect of the invention, the first and second rollers each have first and second end sections with a first outer diameter and a middle section with a second outer diameter. The first outer diameter is greater than the second outer diameter, such that the first and second ends of the rollers define shoulders. The shoulders advantageously prevent the mooring line from slipping off the roller. 
     According to another aspect of the invention, the first and second rollers are made of a slightly compressible material, such as polyurethane. The slight compressibility advantageously enables the mooring line to grip the roller and aid rotation of the roller. As a result, the mooring line does not slip along the roller, thus increasing the line handler&#39;s control over line-handling evolutions. 
     According to another aspect of the present invention, the first and second sides of the frame are substantially perpendicular to each other, such that the axes of the first and second rollers each define approximately 45-degree angles with the surface of the marine vessel. As a result, the line handler is able to perform line-handling evolutions in an erect body position instead of a bent-over body position. 
     Thus, the line handler is able to use more body strength than the line handler could use in either a bent-over body position or standing erect when using a prior art bitt, and is less susceptible to back injuries than in a bent-over body position. Also, the hands of the line handler are further from the bitt, thus reducing likelihood of hand injuries during line-handling evolutions. Finally, by performing line-handling evolutions in an erect body position, the line handler is able to achieve a higher situation awareness during potentially dangerous line-handling evolutions than is possible when the line handler is in a bent-over body position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The preferred and alternative embodiments of the present invention are described in detail below with reference to the following drawings. 
     FIG. 1 is a side view of an embodiment of the invention; 
     FIG. 2 is a side view of an alternate embodiment of the invention; 
     FIG. 3 is a side view of components of the invention; 
     FIG. 4 is a side view of the invention in use; 
     FIG. 5 is a side view of an alternate embodiment of the invention; and 
     FIG. 6 is a side view of another alternate embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows a bitt  10  with a freely rotatable line-handling surface according to the present invention. The bitt  10  permits a line handler to perform line-handling activities in an erect body position instead of a bent-over position. Further, the freely rotatable line-handling surface included in the bitt  10  allows much of the line handler&#39;s energy to be applied to useful work in drawing a marine vessel along side a pier instead of being wasted in overcoming line friction. 
     Referring to FIG. 1, the bitt  10  includes a base  12 . The base  12  is substantially planar and is suitably a rectangular base plate. The base  12  defines bores  14 , shown in phantom, that extend through the base  12  from a top surface  16  of the base  12  to a bottom surface  18  of the base  12 . The bores  14  each define an axis a in a direction that is perpendicular to the plane of the base  12 . The bores  14  are sized to receive mounting hardware suitable for mounting the base  12  to a surface of a marine vessel (not shown). As is known in the art, the base  12  may be mounted on a deck at the marine vessel. However, it will be appreciated that the base  12  may be mounted on other surfaces of the marine vessel. For example, the base  12  may be mounted on a bulkhead. Mounting the base  12  on a bulkhead may be desirable to locate the bit  12  adjacent a chock. The bores  14  are suitably located toward end sections  20  of the base  12 . The base  12  is suitably made from a plate of metal that is appropriate for mounting marine hardware to the deck of a marine vessel. The base  12  is therefore suitably made from stainless steel, such as #317 stainless steel. If desired, the base  12  may be plated with chrome to present an enhanced appearance. 
     A frame assembly  22  is attached to the top surface  16  of the base  12 . The frame assembly  22  is generally an inverted “V”-shaped assembly. The frame assembly  22  includes a first frame member  24  and a second frame member  26 . The first and second frame members  24  and  26  are generally planar. The first frame member  24  has a first end  28  and a second end  30 , and the second frame member  26  has a first end  32  and a second end  34 . The first and second frame members  24  and  26  are attached to each other at the first ends  28  and  32 , respectively, and define an angle α that is preferably substantially 90 degrees. It will be appreciated that any angle α may be selected as desired for a particular line-handling application. It will also be appreciated that the frame assembly  22  may be made of unitary construction, such as from angle iron or the like, if desired. The second ends  30  and  34  of the first and second frame members  24  and  26 , respectively, are attached to the top surface  16  of the base  12 . The first and second frame members  24  and  26  are preferably attached to each other and to the top surface  16  of the base  12  by acceptable methods of joining metal, such as tungsten-inert-gas (TIG) welding or metal-inert-gas (MIG) welding. The frame assembly  22  is preferably centered on the base  12 . That is, the first ends  28  and  32  of the first and second frame members  24  and  26  that form an apex of the inverted “V”-shaped frame assembly  22  are preferably positioned approximately midway between the end sections  20  of the base  12 . The second ends  30  and  34  of the first and second frame members  24  and  26 , respectively, are attached to the top surface  16  of the base  12  at points that are intermediate the midpoint of the base  12  and the bores  14 . Thus, the frame assembly  22  is generally centered on the base  12 , and the bores  14  are defined toward the end sections  20  of the base  12 , such that line-handling forces are distributed substantially evenly about the frame assembly  22  and the base  12 . Intermediate the first end  28  and second end  30  and intermediate the first end  32  and second end  34 , the first and second frame members  24  and  26  define bores  35  that extend through the first and second frame members  24  and  26  along axes that are substantially perpendicular to the planes of the first and second frame members  24  and  26 . 
     Referring now to FIGS. 1 and 3, a first shaft  36  and a second shaft  38  extend outwardly from the planes of the first and second frame members  24  and  26 , respectively. The first and second shafts  36  and  38  are suitably any shaft known in the art, such as a rod, a threaded rod, a bolt, or the like. The first and second shafts  36  and  38  are preferably made from the same material as the first and second frame members  24  and  26  to minimize possibility of inducing galvanic corrosion due to joints between dissimilar metals. The first and second shafts  36  and  38  each define an axis b. The first shaft  36  has a first end  40  and a second end  42 , and the second shaft  38  has a first end  44  and a second end  46 . The second ends  42  and  46  are received within the bores  35 . The first and second shafts  36  and  38  are attached to the first and second frame members  24  and  26 , respectively, such that the axes b of the first and second shafts  36  and  38  are substantially perpendicular to the plane of the first and second frame members  24  and  26 . As such, the axes b each define approximately 45-degree angles with the plane of the base  12  when the angle α is approximately 90°. It will be appreciated that the angle α and the axes b cooperate to define the angle between the axes b and the plane of the base  12 . As shown in FIG. 1, a 45-degree angle accommodates many entry angles between a marine vessel and a pier. However, the angles α and the axes b may be selected as desired for any application. The first and second ends  44  and  46  of the first and second shafts  36  and  38 , respectively, are attached to the first and second frame members  24  and  26  in an acceptable manner known in the art. For example, the second ends  42  and  46  may be welded to the first and second frame members  24  and  26 . When the shafts  36  and  38  are bolts, the heads of the bolts may be welded to the first and second frame members  24  and  26 . Alternatively, the second ends  42  and  46  may be threaded, and the bores  35  are threaded and are arranged to threadedly receive and engage the second ends  42  and  46  of the first and second shafts  36  and  38 . However, it will be appreciated that the second ends  42  and  46  are suitably attached to the first and second frame members  24  and  26  in any acceptable manner that is known in the art. As shown in FIG.  1 . the first ends  40  and  44  of the first and second shafts  36  and  38 . respectively, are unattached to any other structure. 
     The first and second shafts  36  and  38  each rotatably receive first and second rollers  48  and  50 , respectively, that provide rotatable line-handling surfaces. The first and second rollers  48  and  50  each have a longitudinal axis c. The first roller  48  has a first end section  52 , a second end section  54 , and a middle section  56 . The second roller  50  has a first end section  58 , a second end section  60 , and a middle section  62 . The first and second rollers  48  and  50  each define longitudinal bores  64 , shown in phantom, that extend from the first end sections  52  and  58  through the first and second rollers  48  and  50  to the second end sections  54  and  60 . The bores  64  are sized to have a diameter that is slightly larger than a diameter of the first and second shafts  36  and  38 . 
     The first end sections  52  and  58  and the second end sections  54  and  60  each define shoulders  66 . Each of the shoulders  66  is preferably identical, and a description of the shoulder  66  at the first end section  52  of the first roller  48  is representative of all the shoulders  66 . The first end section  52  defines a first outer diameter. The first outer diameter is substantially constant and extends a finite distance d laterally toward the middle section  56 . The middle section  56 , the outer diameter of the first roller  48  decreases along the finite distance d, preferably constantly, to a second outer diameter that is less than the first outer diameter. In one embodiment of the invention, the constant decrease in the outer diameter of the first roller  48  defines a shoulder surface  68  that defines an angle β with the axis c. In one embodiment of the invention, the angle β is approximately 45 degrees. It will be appreciated that the angle β can be any angle as desired. Alternate embodiments of the present invention that vary the angle β are discussed later. 
     The first and second rollers  48  and  50  are each suitably constructed of a compressible material, such as polyurethane, or the like. According to the invention, slight compressibility of the first and second rollers  48  and  50  permits the mooring line to grip the first roller  48  or the second roller  50 , as desired. A readily available roller, for example, is the RP-5, available from the Stoltz Company. However, it will be appreciated that the first and second rollers  48  and  50  may be made of other suitable materials. For example, the first and second rollers  48  and  50  may be made from the same material used for the first and second shafts  36  and  38 . In this alternate embodiment, exterior surfaces of the first and second rollers  48  and  50  are treated in any acceptable known manner to provide non-skid surfaces to permit mooring lines to grip the line-handling surfaces of the first and second rollers  48  and  50 . 
     The first and second shafts  36  and  38  receive the bores  64  of the first and second rollers  48  and  50 , respectively. Thus, the first and second rollers  48  and  50  are rotatably mounted on the first and second shafts  36  and  38  such that the axes c are aligned with the axes b. Because the diameter of the bores  64  is slightly greater than the diameter of the first and second shafts  36  and  38 , the first and second rollers  48  and  50  freely rotate about the axes c. Retainers  70  are placed on the second ends  42  and  46  of the first and second shafts  36  and  38 , respectively, and retain the first and second rollers  48  and  50  on the first and second shafts  36  and  38 , respectively. The retainers  70  are acceptably any retainer known in the art, such as a locknut, a pin, a cotter pin, or the like. When the retainer  70  is a locknut, the second ends  42  and  46  of the first and second shafts  36  and  38  are threaded, and the retainers  70  are threadedly received about the second ends  42  and  46  of the first and second shafts  36  and  38 . As shown in FIG. 1, the second end sections  54  and  60  are unattached to any other structure. 
     Use of the invention will be explained referring now to FIG.  4 . As a marine vessel (not shown) approaches a pier  72 , a mooring line  74  is secured to the pier  72 . The line handler (not shown) gives the mooring line  74  a half-turn around one of the first and second rollers  48  and  50 , as desired. As shown by way of non-limiting example in FIG. 4, the mooring line  74  is given a half-turn around the second roller  50 . It will be appreciated that when the mooring line  74  is given a half-turn on the shoulder  66 , any pier-side entry angle of the mooring line  74  can be accommodated because, as shown in FIG. 4, the second end sections  54  and  60  are unattached to any other structure. Because the first outer diameter at the first end section  58  is greater than the second outer diameter at the middle section  62 , the mooring line is prevented from slipping off the second end  60  of the second roller  50 . The line handler (not shown) pulls the mooring line  74  in a direction denoted by an arrow  76 . Because of compressibility of the roller  50 , the mooring line  74  grips the surface of the roller  50 , and the roller  50  rotates about the axis c. Because the roller  50  rotates about the axis c, much of the energy by the line handler (not shown) is translated into useful work in drawing the marine vessel (not shown) to the pier  72 . 
     Still referring to FIG. 4, according to the invention the bitt  10  is used when the marine vessel (not shown) is tied to the pier  72 . One end of the mooring line  74  is secured to the pier  72 . The mooring line  74  is given turns as desired around the first and second rollers  48  and  50 . A bottom turn of the mooring line  74  rests upon the shoulder surfaces  68  at the first end sections  52  and  58  of the first and second rollers  48  and  50 . It will be appreciated that the shoulder surfaces  68  are substantially parallel to the plane of the base  12 . Thus, the shoulder surfaces  68  prevent the mooring lines  74  from slipping off the first and second rollers  48  and  50 . 
     Referring now to FIG. 2, an alternate embodiment of the invention is shown. A bitt  100  includes a frame assembly  22 , first and second shafts  36  and  38 , first and second rollers  48  and  50 , and retainers  70  as described above for the embodiment shown in FIG.  1 . However, in this alternate embodiment, the frame assembly  22  includes extensions  102  that are similar to the end sections  20  of the base  12  of the embodiment of FIG.  1 . As such, the extensions  102  define the bores  14  as in the embodiment shown in FIG.  1 . However, it will be appreciated that the bitt  100  provides a unitary frame assembly with extensions for mounting the bitt  100  to the deck of a marine vessel (not shown). Alternatively, instead of a unitary construction, the extensions  102  may be attached to the frame assembly in any acceptable, known manner, such as welding as described above for the bitt  10 . 
     Referring now to FIG. 5, another alternate embodiment of the invention is shown. A bitt  200  includes a frame assembly  22 , first and second shafts  36  and  38 , and retainers  70  as described above for the embodiment shown in FIG.  1 . However, in this alternate embodiment, first and second rollers  248  and  250  each define substantially constant outer diameters. It will be appreciated that the bitt  200  may be desirable in applications where space constraints indicate that rollers without shoulders may be desirable. 
     Referring now to FIG. 6, a further alternate embodiment of the invention is shown. A bitt  300  includes a frame assembly  22 , first and second shafts  36  and  38 , and retainers  70  as described for the embodiment shown in FIG.  1 . In this alternate embodiment, first and second rollers  348  and  350  each define substantially constant outer diameters. However, the rollers  348  and  350  each define flanges  352  at each end. The flanges  352  extend from first and second ends  354  and  356  of the rollers  348  and  350  substantially perpendicular to the axes of the rollers  348  and  350 . The flanges  352  provide a shoulder-like surface for retaining a mooring line on the roller. It will be appreciated that use of the rollers  348  and  350  may be desirable in applications similar to applications for the rollers  248  and  250 . 
     While the preferred embodiment of the invention has been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. Accordingly, the scope of the invention is not limited by the disclosure of the preferred embodiment. Instead, the invention should be determined entirely by reference to the claims that follow.