Patent Publication Number: US-7594642-B2

Title: High load connection system

Description:
FIELD OF INVENTION 
   This invention relates to simple lightweight construction methods for connections of high tensile loads utilizing molded parallel fiber bundles which can be applied to numerous applications, including sail boat stays, shrouds and blocks etc. 
   BACKGROUND 
   Historically, these high loads and their connections have been taken by metal stays, shrouds and blocks. These have all been have been constructed using meta including stainless steel, resulting in relatively high weight and in stays, metal tapered compression cones. 
   Recently more advanced designs have replaced some metal with high strength braid, such as Spectra, Dyneema, PBO and carbon fiber etc. with a resultant reduction in weight, Since in a yacht, reduction in weight can be directly translated into improved performance, there exists a need to further reduce weight in high load yacht fittings, such as stays, blocks and shrouds. 
   Practability and termination of these newer systems however make them difficult to commercialize. 
   Lightweight blocks using braid connections are limited in some applications, where a more rigid construction is more appropriate. 
   SUMMARY OF THE INVENTION 
   The present invention relates to a design utilizing molded unidirectional high strength fiber bundles and their termination to take the major tensile loads with a subsequent reduction in metal mass to produce stays, shrouds and blocks with reduced weight and hence increased performance under high loads compared to the current state of the art. 
   An object of an embodiment of the invention is to provide a rigid high load lightweight block with a reduced mass employing unidirectional high strength molded fiber bundles in the side plates for the carrying of the major operating tensile loads within the block, thereby minimizing the weight and maximizing the load of the assembly. These high strength fiber bundles, such as carbon microfibers, are molded using plastic resin such as epoxy to form a rigid structure. This new technique or invention provides less metal in the block and increases the strength to weight ratio compared to current designs. 
   Another object of an embodiment of the invention is to provide a rigid high load lightweight block with a reduced mass employing unidirectional high strength molded fiber bundles for the primary load carrying major operating tensile loads within the block thereby reducing the weight of the assembly, and where the unidirectional molded fiber bundles are terminated and secured to the boat without the use of metal fasteners reducing the amount of metal in the block compared to current designs. 
   Another object of an embodiment of the invention is to provide a rigid high load lightweight block with a reduced mass employing unidirectional high strength molded fiber bundles in the side plates for the carrying of the major operating tensile loads within the block coupled with lightweight non metallic compression members separating the said fiber bundles, thereby reducing the weight of the assembly. This new technique or invention provides less metal in the block and increased strength lightweight rigid construction compared to current designs. 
   Another object of an embodiment of the invention is to provide a rigid high load lightweight block with a reduced mass employing unidirectional high strength molded fiber bundles in the side plates for the carrying of the major operating tensile loads within the block. 
   These tensile fiber bundles being encased within a relatively low strength molded plastic housing. 
   This new technique or invention provides less metal in a high load lightweight rigid block construction compared to current designs. 
   Another object of an embodiment of the invention is to provide a system for tensile connection with a reduced mass employing unidirectional high strength molded fiber bundles for the carrying of the tensile loads, such as shrouds and stays, terminated by rigid unidirectional high strength molded fiber bundle end pieces glued thereto. 
   Another object of an embodiment of the invention is to provide a system for tensile connection with a reduced mass employing unidirectional high strength molded fiber bundles for the carrying of the tensile loads, such as shrouds and stays, terminated by rigid unidirectional high strength molded fiber bundle end pieces connected thereto, where the central portion of the fiber bundles is not molded and hence remains flexible or is molded with a flexible plastic. 
   In one broad form the invention provides a rigid block having at least one sheave mounted between opposed side plates for rotation about at least one corresponding axis, said block including at least one substantially rigid unidirectional fiber bundle engaging or integrated into at least one of the side plates whereby a tension load applied to said at least one sheave is transferred via the at least one the side plate to the at least one fiber bundle. 
   The at least one fiber bundle is may be formed separately separate from the at least one side plate and attached thereto. 
   The at least one fiber bundle may be integrated into at least one side plate. This may be by encasing the fiber bundle with material that is also used to form the side plate. 
   At least part of the at least one fiber bundle may be molded. 
   The or each at least one fiber bundle may engage two or more side plates. 
   The or each fiber bundle may be comprised of a plurality of fiber strands. At least some of the plurality of fiber strands may be laid end on end and the ends of the fiber strands may overlap. 
   The or each fiber bundle may be formed of a single fiber strand. 
   The or each at least one fiber bundle may form at least one continuous loop and in embodiments form at least two continuous loops. The at least one fiber bundle may have ends, i.e. the fiber bundle does not form a continuous loop. 
   The block may include a first sheave mounted between a first pair of side plates, for rotation about a first axis, and a second sheave mounted between a second pair of side plates, for rotation about a second axis, said second axis spaced from the first axis, with at least one fiber bundle engaging or integrated into first and second side plates. 
   The first and second axes may be parallel and transversely spaced from each other. Alternatively, the first and second axes may be orthogonal to each other. 
   The or each fiber bundle may form a continuous loop and engages or be integrated into at least one first and at least one second side plates. 
   The block may have a fiber bundle forming a continuous loop that engages or is integrated into both first and both second side plates. 
   The block may include at least one spacer that engages spaced apart portions of at least one fiber bundle. The spacer may engage spaced apart portions of at least one fiber bundle located on the same side of a sheave. The spacer may engage spaced apart portions of at least one fiber bundle located on opposite sides of a sheave. 
   Preferably the at least one fiber bundle passes around the corresponding axis. 
   Preferably application of tension load to the sheave and the at least one fiber bundle places the or each side plate engaged by the at least one fiber bundle in compression. 
   Preferably the at least one side plate is non-metallic. 
   The at least one fiber bundle may have ends adapted to be secured in or to the structure of a boat. 
   The invention also provides the combination of a boat and the block as described above. 
   The boat may be provided with a wall and the ends of the at least one fiber bundle extend into respective recesses in the wall and are secured thereto. The recesses may include bores extending through the wall. The ends of the at least one fiber bundle may extend from a first side of the wall to the other side and are secured to the other side of the wall. The ends of the at least one fiber bundle may be received in hollow plugs received in the bores. At least one of the plugs may include a connector for connection of a tension member, to transfer load from the respective fiber bundle via the plug and the tension member to another part of the boat. 
   The invention also provides an elongate tension member comprising at least one bundle of unidirectional fibers the elongate tension member having connectors at each end thereof. The connectors may be glued or bonded to the ends of the at least one bundle of fibers. 
   The connectors may be formed of fibers encased in a resin. The ends of the at least one bundle of fibers may be received in recesses in the connectors. The end portions of the at least one bundle of fibers may be substantially rigid. 
   At least an intermediate portion of the at least one bundle of fibers between the end portions may be flexible. The intermediate portion may be substantially comprised of fibers without resin. The intermediate portion may be comprised of fibers molded or encased with a flexible resin. 
   Unless the context clearly requires otherwise, throughout the description and the claims the words ‘comprise’, ‘comprising’, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows an isometric view of a high load lightweight mast base block assembly with molded high strength fiber bundles employed to take the major tensile loads of the block together with a lightweight non metallic connection system. 
       FIG. 1   a  shows an alternative leg and termination construction to that of  FIG. 1 . 
       FIG. 1   b  shows an isometric view of the termination tube of  FIG. 1 . 
       FIG. 2  shows an isometric view of the mast base block of  FIG. 1 , with the addition of a tensile load support rod. 
       FIG. 2   a  shows an isometric view of alternative termination tube to that of  FIG. 1   b.    
       FIG. 3  shows an isometric view of a high load lightweight utility block with molded high strength fiber bundle side plates employed to take the major tensile loads of the block with multiple attachment possibilities. 
       FIG. 4  shows an isometric view of a high load lightweight block with molded high strength fiber bundles employed to take the major tensile loads of the block with the addition of a Becket. 
       FIG. 4   a  shows an isometric view of a high load lightweight block with molded high strength fiber bundles employed to take the major tensile loads of the block with the addition of a second sheave to form a spriddle block together with a swivel connection employing a soft loop. 
       FIG. 5  shows an isometric view of a high load lightweight utility block with molded high strength fiber bundles employed to take the major tensile loads of the block, encased within molded low strength side plates. 
       FIG. 6  shows an isometric view of a high load lightweight utility block with molded high strength fiber bundles employed to take the major tensile loads of the block, in the form of a two to one block. 
       FIG. 7  shows an isometric view of a lightweight shroud or stay with fiber bundle and end assemblies used for the support of high tensile loads, without the use of metal. 
   

   DETAILED DESCRIPTION OF PREFERRED AND OTHER EMBODIMENTS 
     FIG. 1  shows a mast base block  1  according to the present invention with sheave  6 , shaft  2  and non metallic compression member  3   a  (opposite compression member  3   b  not visible). 
   High strength molded fiber bundles  4   a  and  4   b  with single elements of fiber bundles partially shown at  7  are molded or glued to compression members  3   a  and  3   b  respectively 
   Fiber bundles  4   a  and  4   b  have rectangular (or circular) cross sections and are aligned to carry primarily tensile loads and extend below sheave  6  and through deck  5 . The cross section of the bundles may be other shapes. 
   The legs of the fiber bundles  4   a  and  4   b  are molded into a circular cross section at deck level and protrude into deck tubes  14   a, b, c , and  d  in the deck  5  at  10   a, b, c , and  d.    
   Alternatively, the legs can be glued directly into the deck  5  or, as shown, can employ optional molded tubes  14   a, b, c , and  d  and with beads  13   a, b, c , and  d . Optional tubes  14   a, b, c , and  d  can be used to eliminate the normally used high strength compression plugs. 
   Tubes  14   a, b, c , and  d , have central holes, shown by dotted lines,  11  which slide over legs  10 . 
   Legs  10   a, b, c  and  d  are fitted into the pre drilled deck. Tubes  14   a, b, c , and  d , are then fitted from below deck around circular leg portions  10   a, b, c , and  d  via counter bores  12   a, b, c , and  d . The assembly is completed by using glue or resin around legs  10   a, b, c , and  d  and tubes  14   a, b, c , and  d.    
   This construction provides a rigid high load light weight block assembly without the need for traditional heavy metal construction within the block or for the traditional heavy metal mounting bolts. 
     FIG. 1   a  shows an alternative leg where solid portion of leg  4  is molded leaving fibers without molding resin at  16 . In this variation, legs are applied with resin or glue and fitted to holes in the deck with fibers extending below deck and spread under deck and applied with resin, which upon setting forms a solid anchor. 
     FIG. 1   b  shows a restraining tube of  FIG. 1  constructed using parallel fibers shown at  7  running primarily longitudinally with sufficient fibers to prevent splitting running at right angles to fibers  7  shown at  9 . 
   Alternatively, fibers could also be oriented at an angle shown by  5   a  and  5   b , with the major orientation of the fibers being longitudinally. 
   Fibers are compressed at light angles to the hole axis to form head  13 . 
     FIG. 2  shows a below deck tension member  64  for supporting loads  66  of mast base block  1  of  FIG. 1 . Tension support member  64  is usually terminated at  68  by attachment to mast or floor frames, (not shown). 
   Tension member  64  is constructed according to the invention, using parallel high strength fiber bundles molded into a rod with glued on end connection pieces  70   a  and  70   b.    
   In this embodiment, restraining tube  69  is formed using molded parallel fibers with circular head  72  and cross hole, not visible. Rod end  70   a  is fitted to head  72  of restraining tube  69  and secured by pin  74 . 
   Rod  64  may be rigidly molded using parallel fiber bundles and resin throughout, or by the parallel fiber bundle being molded into heads  70   a  and  70   b  so that no resin is applied to central portion  78 , to make an even lighter construction which is flexible and also more easily transported. 
     FIG. 2   a  shows the construction detail of tube end  69  with central hole  73  and cross hole  71 . Molded fibers  70   a ,  70   b  and  70   c  run longitudinally along tube  69  and around head  72  forming cross hole  71  with minor fibers  79  to avoid splitting of tube to form a lightweight high tensile non metallic rigid connection head suitable for gluing to leg  10 , or rod  64  of  FIG. 2 . 
   In an alternative constriction, fibers  74   a ,  74   b  and  74   c  run primarily longitudinally but are crossed to form a tube which resists splitting. 
     FIG. 3  shows a block  20  with sheave  22 , shaft  24 , high strength fiber bundles  26   a ,  26   b , with partial single fiber elements shown at  27  and compression member  28 . Compression member  28  is usually made from a plastic able to withstand high compression. Compression member  28  allows wide spacing of side fiber bundles  26  at  30 , to act as a rope guide into sheave  22 . 
   Fiber bundle legs  26   a  and  26   b  are molded continuously so that multiple connection methods such as webbing or swivel (not shown) can be used to connect tensile loads shown at  30  and  32  to be taken primarily by fiber bundle legs  26   a  and  26   b.    
   Bolts  33  secure piece  34  which is shaped to allow webbing connection, or swivel connection via hole  36 . 
     FIG. 4  shows a block  40  with sheave  41  similar to that of  FIG. 2  having plastic side plates  42   a  and  42   b  (hidden) with an enlarged central hole  44 , and tubular shaft  46  employing roller bearings (not shown). 
   Molded parallel fiber bundles  48   a  and  48   b  are connected to side plates  42   a  and  42   b , with partial single fiber elements shown at  49 . When loads shown at  60   a  and  60   b  and  62  are applied, side plates transfer loads via shaft  64  and sheave  41  and side fiber bundles  48   a  and  48   b  through end piece  50  and swivel assembly  52 ,  54  to connection  61 . 
   In this embodiment, side fiber bundles are continuous as shown. 
     FIG. 4  also shows part of fiber bundle  42   a  and  42   b  extended to wrap around secondary side plates  54   a  and  54   b  which contain a secondary shaft  56  forming a Becket to which load  62  is connected. 
   End piece  50  rests on lower portion of fiber bundles  42   a  and  42   b  and has a central hole through which soft loop  52  passes. 
   Soft loop  52  is terminated in body  54  and said swivel assembly allows connection to boat while allowing block  41  to rotate. 
     FIG. 4   a  shows a block  80  similar to block  40  of  FIG. 4  but with second sheave  82  in place of the Becket  56  of  FIG. 4 . 
     FIG. 5  shows a block  64  with shaft  67  and molded side plates  67   a  and  67   b  with an assembly bolt head shown at  63 . 
   The major tensile loads shown by arrows  66   a ,  66   b  on one side and  65  on the opposite side, are taken, according to the invention, by largely continuously wound fiber bundles which run around the periphery of block  64  shown visibly by  68   a  and  68   b  with single fiber elements within molded bundles  68  shown at  61   a  and  61   b  and encased within side plates  67   a  and  67   b . Lower portion  69  of block  64  is configured to include alternative attachments such as swivel or webbing. 
     FIG. 6  shows an alternative two to one block arrangement  70  comprising two sheaves  72  and  78  with shaft heads  74  and  75  respectively. 
   According to the invention, rigid wound and molded high strength fiber bundle  76  with single fiber elements within molded bundles  76  shown partially at  76   a  run around block  70  to take the majority of the loads shown at  82  and  84 . Side plate members  79  and  80  locate shafts  74  and  75  and absorb compression loads shown by allows at  86  and  87  while an optional separation plate  77  divides the block, to form an extremely lightweight compact rigid two to one block. 
     FIG. 7  shows a tensile connection device  90  which can be applied to stays or shrouds, comprising high strength molded fiber bundles shown at  92 ,  93 ,  94  and  96 , glued to ends  97   a  and  97   b  and  98   a  and  98   b . Stay  90  is designed to take tensile loads applied through shafts through holes  99  and  100  and central shaft  95 . Ends  97  and  98  being similar in construction to end  72  of  FIG. 2   a.    
   Tensile members shown at  92 ,  93 ,  94  and  96  can be made up of rigid molded fiber bundles as described herein or may be loose or flexibly molded at these points  92 ,  96 ,  93  and  94  and then glued into ends  97   a  and  97   b  and  98   a  and  98   b  shown by  101   a  and  101   b  and  102   a  and  102   b  respectively. 
   It should be noted that the concepts disclosed are not meant to be complete or define a particular model or limit the concepts or application in any way. 
   From the foregoing it should be readily evident that that there has been provided an improved lightweight high load block assembly and connection method.