Abstract:
A safety system of a harness, in particular of the trapezoidal type, is suitable for use on watercraft such as a yacht or windsurfer. A basic element ( 10 ) is coupled to the harness. A hook ( 15 ), suitable for being hooked by a cable, is coupled to the basic element ( 10 ). The basic element ( 10 ) has a first piece ( 31 ) connected to the harness and a second piece ( 30, 15 ) that can be disconnected from said first piece ( 31 ). The first piece ( 31 ) is coupled to the second piece ( 30, 15 ) by a coupling ( 32 ) that can be removed.

Description:
BACKGROUND OF THE INVENTION 
   The present invention refers to a harness, in particular of the trapezoidal type, suitable for use on watercraft such as yachts or windsurfers. More specifically it refers to a safety system of the harness. 
   When a boat leans over on one side because of the wind or the speed that has to be kept, it is usual for sailors to lean over the side of the boat to compensate for the inclination using their own weight. The trapezoidal type of harnesses are used, which can be connected to cables connected to the mast of the boat, to allow the sailors to lean over as much as possible without falling into the water. 
   It can happen, though, that in the event of danger, for example if the boat capsizes, it is difficult if not impossible to unhook the cable of the harness sometimes resulting in disastrous consequences for the sailors. 
   SUMMARY OF THE INVENTION 
   In view of the state of the art as described, the object of the present invention is to provide a safety system for unhooking the harness from the cable. 
   In accordance with the present invention, this object is achieved by means of a harness suitable for use on watercraft comprising a basic element coupled to the harness and a hook, suitable for being hooked to a cable, coupled to the basic element. The basic element comprises a first piece connected to the harness and a second piece that can be disconnected from the first piece. The first piece is coupled to the second piece by means of a coupling means that can be removed. Thanks to the present invention, a safety system can be made for unhooking the harness from the cable and which can be installed on all models of the trapezoidal type of harness without making any modifications and just by replacing the hooking plate. Further, this system is of easily realization and low cost because it comprises simple mechanical parts, of which one is disconnectable from the harness in case of necessity. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The characteristics and advantages of the present invention will appear evident from the following detailed description of some of its embodiments, illustrated as non-limiting examples in the enclosed drawings, in which: 
       FIG. 1  represents a plate for hooking the cable of a trapezoidal harness in accordance with the known art; 
       FIG. 2  represents a section of  FIG. 1  according to line II-II; 
       FIG. 3  represents a plate for hooking the cable of a trapezoidal harness, in the closed position, in accordance with a first embodiment of the present invention; 
       FIG. 4  represents a section of  FIG. 3  according to line IV-IV, in the open position; 
       FIG. 5  represents a hooking plate seen from above the cable of a trapezoidal harness, in the closed position, in accordance with a first embodiment of the present invention; 
       FIG. 6  represents a plate for hooking the cable of a trapezoidal harness, in the closed position, in accordance with a second embodiment of the present invention; 
       FIG. 7  represents a plate for hooking the cable of a trapezoidal harness, in the closed position, in accordance with a third embodiment of the present invention; 
       FIG. 8  represents a plate for hooking the cable of a trapezoidal harness, in the closed position, in accordance with a fourth embodiment of the present invention; 
       FIG. 9  represents a plate for hooking the cable of a trapezoidal harness, in the closed position, in accordance with a fifth embodiment of the present invention, with a partial view of the harness; and 
       FIG. 10  represents a plate for hooking the cable of a harness, in the closed position, in accordance with a sixth embodiment of the present invention, with a partial view of the harness. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   We now refer to  FIG. 1 , in which a hooking plate  10  of the cable of a trapezoidal harness is shown in accordance with the known art, and to  FIG. 2 , which represents a section of  FIG. 1  according to line II-II. 
   The hooking plate  10 , normally constituted by a tubular metal structure  13  of a rectangular shape, comprises suitable means  12  and  13  for fastening it, by means of suitable belts (not shown), to the harness (not shown) that will be worn by the sailor. 
   A plate  14 , onto which a hook  15  is welded, is welded at the center of the hooking plate  10 . A ring of a cable (not shown) fastened onto the mast of the boat will be hooked onto the hook  15 . 
   We now refer to  FIG. 3 , in which a hooking plate  10  of the cable of a trapezoidal harness is shown, in a closed position, in accordance with a first embodiment of the present invention. 
   In  FIG. 3  elements similar to the elements of  FIG. 1  have the same numerical reference. 
   The plate  14  comprises in this case a first plate  31  fastened onto the tubular metal structure  13  for example by means of welding. A second plate  30 , on which the hook  15  is fastened, is engaged with the first plate  31 . They are fastened to each other so that they can be separated, by means of a pin  32  that comprises a ring  33  to facilitate its removal, which pin is positioned in a hole  34  made in the upper part both of the plate  31  and of the plate  30 . The ring  33  forms a manual grip for removal control. 
   We now refer to  FIG. 4  that represents a section of  FIG. 3  according to line IV-IV, in the open position, and to  FIG. 5  that represents a hooking plate seen from above the cable of a trapezoidal harness, in the closed position, in accordance with a first embodiment of the present invention. 
   The plate  31 , in its lower part, in correspondence with reference  36 , has a U-shaped tooth in which the plate  30  (preferably with the internal corner rounded-off) is rested. 
   In the upper part, the plate  31  has a central cavity  50  in which a portion  51  of the plate  30  can lie. In other words, the plate  31  in the upper part has two side portions with a greater thickness compared to the other parts, thus forming a central hollow, and the plate  30  has in the upper part a vertical central protrusion that can fit into the hollow of the plate  31 . 
   In this manner, when the plates  30  and  31  are brought closer together, the hole  34  on the plate  30  and on the plate  31  are aligned and the locking pin  32  can be inserted. 
   Preferably, the dimensions of these parts of the structure have a dimension which is sufficient for the hole  34  to be made so that the pin  32  can be inserted. 
   A spring  35  is preferably positioned between the plate  31  and the plate  30 , and a housing  37  and  38  of the spring  35  is preferably made in both plates. 
   With plates closed, the pin  32  on one side and the tooth in position  36  hold the plate  30  against the plate  31 . 
   In the event the harness has to be unhooked, the pin  32  is pulled out by pulling the ring  33  from the side and the plate  30  is pushed out by the action of the spring  35  to free it from the plate  31 , thus freeing the cable fastened to the hook  15  from the harness worn by the sailor. 
   The type of material preferred for the system described above is high corrosion resistant stainless steel (for example INOX18/10, or AISI 316L), given its use in the presence of saltwater. 
   The maximum load that can be applied to the hook will be equal to the weight of the athlete, shall we say a maximum of 100 kg (about 1 kN). This is a negligible load for a steel structure of preferably 7 mm. A shear force of 1 kN, on a circular steel structure of 7 mm in diameter leads to a maximum internal stress of about 26 Mpa, low compared to the critical value of almost 1 Gpa for steel. 
   In regard to the stress to be placed on the ring  33  for unhooking, the following theories can be formulated. The load applied to the hook is distributed entirely on the contact of the pin. A linear contact between the locking pin and guide is made. The coefficient of static friction to the steel-steel contact is equal to 0.2. Thus the force to be applied to slip the pin out in this case will be equal to about 200N (about 20 kg-force); normally an athlete can develop much greater traction forces with the shoulder-arm muscle group, and thus the pin can be slipped out without problems. 
   The locking pin  32  and the hole  34  have such a dimension that the pin  32  presents slight friction with the hole  34 , so that it cannot come out unless it is purposely extracted by means of the ring  33 . Preferably, at the end opposite the ring  33 , the pin  32  can be fitted with a fine lead wire, also with a lead seal, that places minimum resistance to the pin coming out, but which prevents the pin  32  from accidentally coming out of its housing. 
   In  FIGS. 6 ,  7  and  8  plates for hooking the cable of a trapezoidal harness are shown, in the closed position, in accordance with different embodiments. 
   In  FIG. 6  the ring  33 , connected to the pin  32 , has been replaced by a cable  60  that slides in a tubular guide  61 , comes out of it and ends fastened to a flying handle  70 . 
   In  FIG. 7  the pin  32  is connected to a rigid slug  62  that slides in a tubular guide  61  and is fastened to a handle  71 , suitably positioned on the tubular metal structure  13 . 
   In  FIG. 8 , in relation to  FIG. 7 , there is another tubular guide  63  to permit the handle  72  to slide more smoothly. 
   In  FIG. 9 , similarly to  FIG. 6 , the pin  32  is connected to a cable  60  that slides in a flexible tubular guide  93 , fastened to a flying handle  73 , inserted in a pocket  90 , preferably provided with Velcro to prevent it from coming out accidentally. In  FIG. 9  a partial view of the harness  91  is also shown with some belts  92  that fasten the hooking plate  10  to the harness itself. 
     FIG. 10  shows a type of harness  94  that is slightly different from the harness  91  of  FIG. 9 , being the type typically used for windsurfing. 
   Instead of the tubular metal structure  13 , in this case, there is a plate  95  fastened to the fabric of the harness  94  below. The plate  14  is fastened onto the plate  95 . On the plate  95  there are also, on the side of the plate  14 , two rows of holes  96  that serve to fasten the plate  95  onto the fabric of the harness  94 . The holes  96  in combination with the holes  97 , positioned on the harness  94 , also serve to close the harness  94  itself by means of a cord. 
   Several embodiments of the present invention have been described, but others are also possible. All the embodiments described up to this point have the closing pin  32  positioned in the upper part and the tooth in position  36  positioned in the lower part, but alternatively they could be inverted. That is, use the hooking plates  10  could be used upside down in relation to the Figures. 
   Alternatively, the plate  30  and the plate  31  could be hooked only by means of the pin  32  without using the tooth on the plate  31  in position  36 , possible suitably positioning the hook  15  and the pin  32  on the plates  30  and  31 . 
   In addition the hollow portion  50  and the portion  51  of the plate  30  could be more than one. 
   As an alternative, to lighten the weight, a structure, preferably full of composite material, for example of carbon, Kevlar and epoxy resins, can be used as the tubular structure  13 . The plate  30  and the pin  32  could still be constituted of steel.