Abstract:
A vang assembly for manipulating a sailboat boom which is hingendly connected to the lower portion of a sailboat mast ( 12 ). The vang assembly includes a rigid and unextensive vang (strut) ( 20 ) connected both to the mast ( 12 ) and to the boom. The first end portion is hingendly attached to the lower portion of the mast below the boom, and the second end portion is hingedly attached to a traveller ( 26 ) sliding on track ( 30 ) fixed to the boom at a location spaced outwardly from the lower portion of the mast. Traveller fore and aft movements are controlled by block and tackle system. Traveller sliding allows to control boom vertical position. When traveller is pulled forward (toward the mast), the boom is forced upwardly by rigid vang working as a strut, when traveller is pulled aftward (opposite the mast), boom is forced downward by the rigid vang working as a tie rod.

Description:
FIELD OF INVENTION  
       [0001]     This invention relates to a vang assembly for controlling the boom of a sailboat.  
       BACKGROUND OF THE INVENTION  
       [0002]     A vang is an adjustable device fitted to the underside of a boom to control the raising or lowering of the boom.  
         [0003]     Vangs typology can be divided into two basic types: soft vangs and mechanical vangs. The most widely used vangs, in particular for smaller boat are soft vangs. A typical soft vang includes a multiple purchase block and tackle system including two or more blocks or pulleys attached to the boom, and a single line having one end secured to one of the pulley systems, with the line having a free end which is pulled out and released manually by the sailor. A soft vang increases sail efficiency by pulling down on the boom in medium or heavy air, thereby increasing the tension in the leech and reducing the spill of wind.  
         [0004]     Soft vangs can only be used to pull down the boom. Thus, in slight winds or when docked, a wire or rope topping lift must be used to support the boom. Use of a topping lift is extremely undesirable because it increases the wind drag of the sailboat. Mechanical vangs represent an improvement over soft vangs in that they may both pull down on the boom and hold up the boom, thus eliminating the need for a wire or rope topping lift. There are four basic varieties of mechanical vangs.  
         [0005]     The first variety is a tackle-equipped rigid vang. These vangs generally comprise a set of telescoping spring-loaded aluminum tubes with a tackle rigging longitudinally associated therewith. When the tackle rigging is tightened, it applies a downward force on the boom and compresses the spring within the telescoping aluminum tubes. As the rigging is loosened, the spring within the telescoping aluminum tubes extends, thus providing support for the boom. Typically, the spring comprises a steel coil; however, compressed-gas cylinder springs are also used.  
         [0006]     A second variety of mechanical vangs are screwdriven or “rotary” vangs. In a screw-driven vang, a large turnbuckle is lengthened or shortened by turning a wheel or a pair of handles in the middle of the turnbuckle. Although capable of providing both tension in the leech and supporting the boom, screw-driven vangs have the serious disadvantage of being difficult and slow to adjust because of their heavy nature.  
         [0007]     A third variety of mechanical vang are hydraulic vangs. Hydraulic vangs typically consist of a cylinder filled with hydraulic oil and a piston. A hydraulic pump controlled from the cockpit actuates the piston inward or outward to control the height of the boom.  
         [0008]     The fourth variety of mechanical vang are flexible column actuated vangs. This type of vang is actuaded with a device that is capable of being moved between a contracted position and an extended position. When the adjustment mechanism is moved to a contracted position, the column is forced to bow arcuately to an arched position and the boom is forced in a downward direction. When the adjustment mechanism is released to extended position, the arcuately bowed column straightens and exerts forces pushing the boom upwardly.  
         [0009]     Mechanical vangs have several serious problems. For the first three types, the telescoping tubes must be carefully maintained to avoid corrosion. In addition, if water is allowed to leak into the telescoping tubes, the metal springs may be particularly subject to corrosion. The telescoping springloaded tubes of these vangs must also be carefully machined, making them relatively expensive. Finally, these vangs are susceptible to denting and bending from transverse forces. Such damage inhibits the telescoping of the tubes, degrading the vang&#39;s performance. The fourth type of mechanical vang does not give a lower limit to the boom movement, making some mainsail operation difficult. Moreover first and fourth mechanical vang type have the serious limitation that the boom hold up control come from a constant elastic force that always needs pull down tackle rigging in force to maintain the boom at the desired level even in slight wind or when docked.  
         [0010]     For these reasons there is an unresolved need in the art of boom vang system to have a simpler and lighter mechanism with hight boom control performance.  
       OBJECT OF THE INVENTION  
       [0011]     It is an object of the invention to provide a vang system made of a rigid and unextensible strut hingedly attached to the mast and hingedly attached to a traveller sliding on a boom fixed track.  
       SUMMARY OF THE INVENTION  
       [0012]     The present invention comprises a vang assembly for manipulating a sailboat boom which is hingendly connected to the lower portion of a sailboat mast. The vang assembly includes a rigid and unextensible vang (strut) connected both to the mast and to the boom. The first end portion is hingendly attached to the lower portion of the mast below the boom, and the second end portion is hingedly attached to a traveller sliding on track fixed to the boom at a location spaced outwardly from the lower portion of the mast. Traveller fore and aft movements are controlled by block and tackle system.  
         [0013]     Traveller sliding allows to control boom vertical position. When traveller is pulled forward (toward the mast), the boom is forced upwarly by rigid vang workin as a strut, when traveller is pulled aftward (opposite the mast), boom is forced downward by the rigid vang working as a tie rod.  
         [0014]     A simpler configuration of the system includes traveller forward movement control only and therefore the upward boom forcing control. In this case the downward boom forcing control is made by a block and tackle traditional vang.  
         [0015]     The boom vang system of the invention completely elimanates the problems above referred to the other mechanical system, in particular avoids any complex mechanical part, such as spring, telescopic pipe, hydraulic pump etc. and therefore avoids necessity of maintenance.  
         [0016]     Boom control is made by a track and traveller system that is a well known extremely reliable and absolutely durable system. The rigid strut made by alluminium, composites or other materials is a strong, light and durable (no maintenance) component of the system.  
         [0017]     Up and down boom control can be easily performed also without tension to the pull down tackle rigging in particular in light wind or when docked. All the mainsail operation become very easy.  
         [0018]     One of the most important advantage of this system, particularly appreciated by racing boat, is the saving of weigth with respect to other mechanical system. Another significant advantage is the possibility to easily use special strut section profile to reduce wind drag.  
         [0019]     The above brief description sets forth rather broadly the more important features and advantages of the present disclosure so that the detailed description that follows may be better understood, and so that the present contributions to the art may be better appreciated. There are, of course, additional features of the disclosure that will be described hereinafter which will form the subject matter of the claims appended hereto. In this respect, before explaining the embodiment of the disclosure in detail, it is to be understood that the disclosure is not limited in its application to the details of the construction and the arrangements set forth in the following description or illustrated in the drawings. The present invention is capable of other embodiments and of being practiced and carried out in various ways, as will be appreciated by those skilled in the art. Also, it is to be understood that the phraseology and terminology employed herein are for description and not limitation.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]      FIG. 1  is a side elevational view illustrating a first embodiment of the mechanical vang of the present invention disposed between the mast and the boom of a sailboat.  
         [0021]      FIG. 2  is a sectional side plan view of the strut ( 20 ) of FIG. 1  showing inside pulling down rigging.  
         [0022]     FIG:  3  is a sectional side plan view of the strut ( 20 ) of FIG. 1  showing inside hold up rigging.  
         [0023]      FIG. 4  is a plan of strut  20 , with an inside view, along the line  44  of  FIG. 1 .  
         [0024]      FIG. 5  is a sectional view along the line  5 - 5  of  FIG. 4   
         [0025]      FIG. 6  is a side view of an additional embodiment of the mechanical vang of the present invention.  
         [0026]      FIG. 7  is a side view of an additional embodiment of the mechanical vang of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0027]     A vang assembly, generally designated  10 , of the present invention is shown in  FIG. 1  positioned between a lower portion of a mast  12  and a boom  16  of a sailboat. The vang assembly broadly includes a rigid strut, generally designated  20 , hingendly connected to the mast  12  with a tang  22  via hinge  24  and hingendly connected to a traveller  26  via hinge  28 . The traveller  26  is sliding on a track  30  fixed below the boom  16 . This embodiment includes an hollow strut  20  made by alluminium or composite material pipe. Sliding traveller  26  is controlled in his forward and aft movements by two rigging systems.  
         [0028]     To pull traveller  26  forward (toward the mast),forcing boom upwarly, a block and tackle system (better described in  FIG. 3 ) inside the hollow strut  20  is provided. This block and tackle system (better described in  FIG. 3 ) ends with ropes  32  and  40 . Rope  32  is coming out from the hight end of strut  20  and is attached to the forward end  34  of the track  30 , rope  40  is coming out from the the low end of strut  20  and, throught blocks  44 , is carried in a proper position in the boat where a clam cleat or similar fixing device can be positioned. Rope  40  is a dynamic type to work as boom shock absorber.  
         [0029]     To pull traveller  26  aftward (opposite the mast), forcing boom downward, a block and tackle system (better described in  FIG. 2 ) inside the hollow strut  20  is provided. This block and tackle system (better described in  FIG. 2 ) ends with ropes  38  and  36 . Rope or wire  38  is coming out from the high end of strut  20  and is attached to the aft end  42  of the track  30 , rope  36  is coming out from the low end of the strut  20  and trought blocks  44  is carried in a proper position in the boat where a clam cleat or similar fixing device can be positioned.  
         [0030]      FIG. 2  is the sectional plan, viewing inside, of hollow strut  20 , described above, with the representation, generally designated  50  of the block and takle system foreseen for aftward pulling (opposite the mast) of traveller  26 . Rope or wire  38  is attached to the aft end  42  of track  30 , going inside hollow strut  20  trought pulley  54 , and is attached to pulley  57 . Rope  58  is attached to pulley  55 , reevs into pulley  57  and is attached to pulley  56 . Rope  36  is attached to pulley  55 , reevs into pulley  56  and  55 , going out from low end of strut  20 , and trought block  44  is carried in a proper position in the boat where a clam cleat or similar fixing device can be positioned. Pulleys  54  and  55  are hinged with pins to the hight and to the low end of strut  20 , while pulley  56  and  57  are free to move inside hollow strut  20 . Rigging system made by ropes  38 ,  58  and  36  and pulleys  54 ,  55 , 56  and  57  provides a mechnical advantage. As will be appreciated by those knowledgeable in the art, there are other well known block and takle system that can be used for the same pourpose of the present invention.  
         [0031]      FIG. 3  is the sectional plan, viewing inside of hollow strut  20 , described above, with the representation, generally designated  60 , of the block and takle system foreseen for forward pulling (toward the mast) of traveller  26 . Rope  32  is attached to forward end  34  of track  30 , going inside hollow strut  20  trought pulley  62  and is attached to pulley  63 . Rope  40  is attached to pulley  64 , reevs into pulley  63  and  64 , going out from low end of strut  20 , and trought block  44  is carried in a proper position in the boat where a clam cleat or similar fixing device can be positioned. Pulleys  62  and  64  are hinged with pins to the hight and to the low part of strut  20 , while pulley  63  is free to move inside hollow strut  20 . Rigging system made by ropes  32  and  40  and blocks  62   63  and  64  provide a mechanical advantage. As will be appreciated by those knowledgeable in the art, there are other well known block and takle system that can be used for the same pourpose of the present invention.  
         [0032]      FIG. 4  provide a plan (view  4 - 4  of  FIG.1 ) with an inside view of strut  20 . This view shows both the boom pulling up system, formed by pulley  63 ,  64 ,  62  and rope  32 ,  40 , and boom pulling down system, formed by pulley  54 , 55 , 56 , 57  and rope  36 , 38 , 58 . Pulley  56 , 57  and  63  are free to move inside the hollow strut  20 . Pulley  54  and  62  are hinged togheter with strut  20  and hinge  28  via pin  21 ; pulley  55  and  64  are hinged togheter with strut  20  and hinge  24  via pin  23 .  
         [0033]     For this embodiment a strut with wing contour type section profile has been used (see  FIG.5 ) for wind drag reduction.  
         [0034]     It is understood that, even if, this profile is a preferred choise for wind drag reduction, every other suitable profile section could be used.  
         [0035]      FIG. 5  is section view  5 - 5  of  FIG. 4 , showing the internal space of strut  20  foreseen for the movement of pulley systems. In this section pulley  57  and  63  can be seen.  
         [0036]     In addition to that above described, there is another embodiment, generally described  100  in  FIG. 6 , where strut  120  doesn&#39;t foresee inside space for block and takle. Strut  120  can be made by alluminium or composite material and in comparison with strut  20  of  FIG. 1  is thiner giving less wind drag and less production costs. This vang assembly broadly includes a rigid strut  120  hingendly connected to the mast  112  with a tang  122  via hinge  124  and hingendly connected to a traveller  126  via hinge  128 . The traveller  126  is sliding on a track  130  fixed below the boom  116 .  
         [0037]     Sliding traveller  126  is controlled in his forward and aft movements by two rigging system.  
         [0038]     To pull traveller  126  forward (toward the mast),forcing boom upwarly, a block  150  and a rope  152  are provided. Rope  152  is attached to forward end  134  of track  130 , reevs into blocks  150 , 170  and  180  going in a proper position where a fixing device can be installed. Rope  152  is a dynamic type to work as boom shock absorber. Rope  152  and block  150  provide a mechanical advantage. As will be appreciated by those knowledgeable in the art, ther are other well known block and takle system that can be used for the same pourpose.  
         [0039]     To pull traveller  126  aftward (opposite the mast), forcing boom downward, a block and tackle system  160  is provided. A rope  163  is reeved between block  161  and  162  for providing mechanical advantage between the two blocks. A first free end of rope  163  passes trought a pulley fixed in the aft end  142  of track  130 , going forward inside the hollow track  130  and trought blocks  170  and  180  going in a proper position where a fixing device can be installed. A second free end of rope  163  is attached to either block  161  or block  162 . As will be appreciated by those knowledgeable in the art, ther are other well known block and takle system that can be used for the same pourpose.  
         [0040]     In addition to that above described, there is another embodiment, generally described  200  in  FIG. 7 , where strut  220  doesn&#39;t foresee inside space for block and takle. Strut  220  can be made by alluminium or composite material and in comparison with strut  120  of  FIG. 6  it has only the boom upwarly control leaving downwarly boom control to a traditional soft block and takle sistem  270 . This vang assembly broadly includes a rigid strut, generally designated  220 , hingendly connected to the mast  212  with a tang  222  via hinge  240  and hingendly connected to a traveller  226  via hinge  228 . The traveller  226  is sliding on a track  230  fixed below the boom  216 . Sliding traveller  226  is controlled in his forward movement by a rigging system.  
         [0041]     To pull traveller  126  forward (toward the mast), forcing boom upwarly, a block  250  and a rope  252  are provided. Rope  252  is attached to forward end  234  of track  230 , reevs into block  250 , going to a cam cleat  254  for pulling. Rope  252  is a dynamic type to work as boom shock absorber. Rope  252  and block  250  provide a mechanical advantage. Rope  252  can be also carried in a proper position of the boat where a fixing device can be installed. As will be appreciated by those knowledgeable in the art, ther are other well known block and takle system that can be used for the same pourpose.  
         [0042]     For downward boom control a soft standard vang  270  is installed. A rope  278  is reeved between block  272  and  276  for providing mechanical advantage between the two blocks. A first free end of rope  278  passes trought cam cleat  276  for pulling. Rope  278  can be also carried in a proper position of the boat where a fixing device can be installed. A second free end of rope  278  is attached to either block  272  or block  276 . As will be appreciated by those knowledgeable in the art, ther are other well known block and takle system that can be used for the same pourpose.  
         [0043]     While preferred embodiments and example configurations have been shown, it is to be understood that various further modifications and additional configuration will be apparent to those skilled in the art. It is intended that the specific embodiments and configurations herein disclosed are illustrative of the preferred and best modes for practicing the invention, and should not be interpreted as limitations on the scope of the invention as defined by the appended claims.