Patent Publication Number: US-2021171172-A1

Title: Sail with a wing profile, rig for wind propulsion means comprising said sail, and related wind propulsion means

Description:
The present invention relates in general to the field of wind propulsion. The invention has been conceived with particular reference to vessels, such as sail boats and the like, however other wind propulsion means are not excluded. 
     More specifically, the invention relates to a sail with a wing profile, a rig for wind propulsion means comprising said sail, and to relative wind propulsion means. 
     In the sail boat sector, the use of the “Bermuda” rig which makes use of the classic triangular sail is particularly widespread. 
     For some time, however, technicians have been studying various alternatives to make boats perform better. 
     One of the most significant attempts in the competitive field is the replacement of sails with rigid wings. They are substantially like the wings of aeroplanes, that is, they differ from sails because instead of being composed of a yielding sheet, generally canvas or similar, they have a thickness shaped to form a solid aerodynamic profile. They generally consist of two shells joined together to form a box. This makes it possible to control the incidence and profile of the wing, with undoubted advantages on lift. 
     However, this solution has considerable disadvantages. First of all, the weight of the rig is much greater than that of a rig with a sail, as it must not only comprise a rigid wing, but also a mast and relative manoeuvres that are strong enough to control it. Certain operations are impossible or are rendered more complicated, such as lowering. It is not currently possible to create variable thicknesses in order to increase lift advantages. For these reasons, the control of such a wing is reserved to professionals, and is not feasible on commercial boats. Last but not least is the very high cost. 
     To partially overcome these drawbacks, sails with a wing profile have been developed, i.e. sails made of yielding material supported by an internal frame which generates the profile. Some examples of this type are known from the prior patent documents DE102014103999, FR2730976 and EP0315963, where sails with an adjustable wing profile are described. In particular, these sails have internal frames deformed by cams that expand the wing profile. However, the profile modification mechanisms are complicated, heavy and delicate, and in some cases are unsuitable for being applied to concave wing profiles. 
     An object of the present invention is to overcome all or some of the drawbacks of the prior art. 
     A preferred object of the present invention is to provide a wind propulsion system that is easy and inexpensive to produce and performs better than the current Bermuda sails. 
     A further preferred object of the present invention is to provide a wind propulsion system that non-professional users can also easily use. 
     Another further preferred object of the present invention is to provide a robust and at the same time lightweight wind propulsion system. 
     Still another further preferred object of the present invention is to provide a wind propulsion system adapted to create asymmetrical wing profiles, for example concave profiles. 
     According to a first general aspect, the present invention relates to a sail with a wing profile comprising at least two layers arranged side by side to form a modifiable aerodynamic profile (for example with adjustable thickness and/or shape), and at least one profiling device of the sail, where said profiling device comprises at least one fork member ( 45 ), associated with said layers, shaped with a wing profile and deformable for generating said modification, said profiling device comprising at least one sliding member inside the fork and parallel to its main extension direction (R) to modify said profile. 
     Preferably, the two layers are made of yielding material, so that they can be moved closer together and away from each other at least partly to modify said thickness and to allow the sail to be folded for lowering. Yielding material must therefore be understood as a material which is at least not permanently deformable by folding, so as to allow lowering. 
     According to certain preferred embodiments, said member is slidable between a maximum deformation position and a minimum or no deformation position of the fork. 
     Advantageously, the sliding member can be used both for exerting a thrust which actively deforms the fork, and as a stop to limit the approach of the sections of the fork facing each other, which in case of strong wind would greatly reduce the profile to the detriment of performance. 
     In the first case the fork can have a resting position corresponding to the minimum expansion, and is affected by the thrust action from the inside towards the outside of the sliding member. 
     In the second case the fork can have a resting position corresponding to the maximum expansion, where members are provided which alter the fork by crushing it with a force directed from the outside towards the inside, such as for example pulling members, and where the sliding member stops the crushing of the fork in the desired configuration. 
     In general, the case is envisaged wherein said sliding member, during its travel, deforms the fork member, for example elastically, and/or generating the relative rotation between at least two portions of the fork member. In practice this is possible by attributing to the sliding member an active thrusting function towards the outside, or a stop point for an elastic portion of the fork which therefore bends to adapt itself. 
     According to certain preferred embodiments, the fork member comprises two sections of rigid battens of the sail which are facing each other, the sliding member being movable between them between a position wherein it exerts a maximum displacement thrust between them and a position wherein it exerts a minimum displacement thrust. 
     In this case it is preferable that the two batten sections are rotatably hinged at one end thereof. 
     The two batten sections preferably have different rigidity. 
     In some cases two batten sections are envisaged of different length. 
     In this case it is preferable that the shorter section is less rigid. 
     According to certain embodiments, during its travel the sliding member modifies the curvature of at least one of the two batten sections, for example between a concave or mainly concave curvature, and a convex or mainly convex curvature, and vice versa. 
     According to certain preferred embodiments of the invention the sliding member is movable between a position wherein the wing profile is concave and a position wherein the wing profile is convex. 
     According to certain preferred embodiments of the invention, the sail comprises return means of the fork towards the minimum expansion configuration, and the sliding member expands the fork during its sliding in opposition to the return means. 
     In this case, preferably, the sail comprises elastic return means and/or movement limiting means of the fork&#39;s ends. 
     According to one particularly preferred example, the fork member comprises a folded forked batten and the elastic return means comprise at least one batten portion, where the sliding of the sliding member elastically deforms the fork. 
     The case is also contemplated wherein the fork comprises a pair of batten sections rotatably joined one with respect to the other, where the elastic return means are operatively interposed between the two battens. 
     According to certain preferred embodiments of the invention, the fork member is normally in a resting configuration corresponding to the maximum thickness of the wing profile, and must be actively deformed to pass to a minimum thickness configuration, where the sliding member is a limiting means of the minimum thickness. 
     In this case, preferably, the sliding of the sliding member regulates the minimum thickness of the wing profile. 
     Among the various possibilities contemplated, we mention that where the forked member comprises two batten sections facing each other, and the profiling device comprises means for pulling the battens towards each other to pass from the maximum thickness to the minimum thickness. 
     In this case it is preferable that the profiling device comprises elastic means arranged to maintain the fork member in the resting position and to oppose said pulling for the passage to the deformed position. 
     For example, the elastic means comprise at least one elastic section of at least one batten. 
     It is also possible that the batten sections form two distal sections of a single folded forked batten, where the elastic means comprise at least one elastic portion of said folded batten. 
     According to certain preferred embodiments of the invention, the aerodynamic profile is concave or mainly concave. 
     In this case it is preferable that the fork comprises two batten sections facing each other and of a shape such as to define said profile, where the internal section of the fork&#39;s concavity is more elastic than the external one, and preferably shorter. 
     The case is envisaged wherein said internal section is deformable to at least partially reverse its concavity. 
     According to a second general aspect, the present invention relates to a sail with a wing profile comprising at least two layers arranged side by side to create a modifiable aerodynamic profile (for example with an adjustable thickness and/or shape), and at least one profiling device of the sail, where said profiling device comprises at least one fork member, associated with said layers, shaped with a wing profile and deformable to generate said modification, said fork member having a resting position corresponding to the maximum thickness of the wing profile, the profiling device comprising a pulling member, active between the sections of the fork facing each other, which can be activated on command to reduce said thickness, and a limiting member of the minimum thickness of the profile, interposed between the portions of the fork facing each other to define its minimum expansion. 
     In this case, preferably, the limiting member is movable with respect to the fork member to adjust the minimum thickness of the aerodynamic profile. 
     According to a preferred characteristic, the limiting member is a cam rotatable between the portions of the fork facing each other or a sliding member between them. 
     According to a third general aspect, the invention relates to a rig for wind propulsion means comprising at least one sail of the type indicated above, and at least one mast to which the sail is coupled. 
     Preferably, the mast defines a U-shaped sliding path for the sail so that it can assume at least two positions mirroring each other. 
     The case wherein the sail has a concave aerodynamic profile is particularly preferred. 
     According to a fourth aspect, the invention comprises wind propulsion means comprising a rig of the type indicated above. 
    
    
     
       Further characteristics and advantages of the present invention will become clearer from the following detailed description of the preferred embodiments thereof, with reference to the appended drawings and provided by way of indicative and non-limiting example. In such drawings: 
         FIG. 1  shows a first example of a wind propulsion system according to the present invention; 
         FIG. 2  shows a sail of the system of  FIG. 1 , 
         FIGS. 3A and 3B  show a profiling device of the sail of  FIG. 2  respectively in a maximum thickness and minimum thickness configuration; 
         FIG. 4  shows a second example of a wind propulsion system according to the present invention; 
         FIG. 5  shows a sail of the system of  FIG. 4 , 
         FIGS. 6A to 6C  show an alternative embodiment of a profiling device according to the present invention in respective operating positions; 
         FIGS. 7A to 7B  show an alternative embodiment of a profiling device according to the present invention in two respective operating positions. 
     
    
    
     With reference to  FIG. 1 , a wind propulsion system is shown which is comprehensively indicated with the reference number  1 . The system comprises a vessel  5 , in turn comprising a hull  10 , and a sailing rig  15 . 
     The sailing rig comprises a sail  20 , a mast  25  for supporting the sail and so-called “manoeuvres”  30 , i.e., the set of means needed to control the sail. 
     The sail  20 , better seen in  FIG. 2 , has an extension in height in the direction H from top to bottom, an extension in width in the direction L from an edge  38   a  proximal to the mast  25  to an edge  38   b  distal from the mast, and an extension in thickness in the direction S orthogonal to its main faces  21  and  22 . 
     The sail  20  comprises a sheet of yielding material  35 , for example canvas or other similar material suitable for making sails. The sheet is folded to be arranged in two side by side layers  36  and  37 . 
     As can be noted, one of the two layers  36  and  37  could be more extended than the other, that is, have a larger area. For example, their difference could exceed 10% of the largest area, more preferably 50% and even more preferably an extension could be about one third of the other. 
     The folding of the sheet  35  forms the edge  38   a  of the sail near the mast  25 , to which it is intended to be hooked. 
     The layers  36  and  37  can end in the direction of the width L of the sail with free edges  44  on a side which is distal from the fold  38   a . In the case of a larger layer, its edge  44  coincides with the distal edge  38   b  of the sail. According to a variant not shown, the layers  36  and  37  can also be joined together at at least one of their edges which is distal from the fold  38   a , preferably maintaining their freedom to slide with respect to each other. In any case, the layers  36  and  37  are arranged to form an aerodynamic profile. 
     The sail  20  comprises a plurality of profiling devices  40 , adapted to modify the sail&#39;s profile, in particular at least its thickness. With reference to  FIG. 3A , each profiling device  40  comprises a stiffening member  45  shaped like a fork according to said aerodynamic profile. The stiffening member  45  comprises a pair of stiffening batten sections  41  and  42  facing each other, each section being intended to be integral, in use, with a respective layer of the adjacent layers  36  and  37 . 
     In the illustrated example, the sections  41  and  42  form the distal sections of a single batten  45  shaped like a fork, in particular they are joined by a proximal section  43  folded and interposed between them. They are arranged orthogonally or substantially orthogonally to the folding edge  38   a.    
     Their joined section  43  is located at the folded edge  38   a.    
     In the illustrated embodiment, the distal sections of the fork are of different lengths, but distal sections of equal length are not excluded. 
     The distal sections  41  and  42  are preferably curved, so as to form an aerodynamic profile with an asymmetrical section, preferably concave or mainly concave. In the case of distal sections  41  and  42  of different length, the shorter faces the inside of the concavity, as shown in  FIG. 3A . 
     The proximal section  43  has sufficient elastic characteristics to allow the non-permanent deformation of the fork of a measurement such as to allow the approach and distancing of at least some of the distal sections  41  and  42  between them. In addition or alternatively, one or both of the distal sections  41  and  42  can be elastic, which renders it easy for example to create a maximum displacement at a central part of one or both of the distal sections  41 ,  42 . In this case, according to certain embodiments, one or more ends of the distal sections  41 ,  42  could be constrained to not vary the distance from the distal section which it is facing. 
     Preferably each fork  40  has zones with different rigidity, in particular the proximal section  43  is preferably more elastic than the others. Even more preferably, one of the two distal sections is more rigid than the other. In the case where the distal sections  41  and  42  are of different length, the most rigid section is the longest one. In general it is preferable that the section  42  inside the concavity is less rigid, and that it can change its concavity, up to becoming preferably also convex or mainly convex. 
     The battens can be permanently joined to the sail, for example by sewing, or can be coupled and uncoupled to it, for example by inserting them in, and removing them from, special pockets formed in the sail. 
     Each fork  40  preferably extends over the entire width L of the sail. In the illustrated embodiment, each fork  40  extends from a free edge  44  to another of the sheet  35 . 
     The opening of the fork, i.e. the maximum distance of the distal sections  41  and  42 , determines the thickness S of the aerodynamic profile of the sail  20 , in particular the maximum thickness. This distance can be increased and decreased to change the aerodynamic profile. 
     Note that it is not excluded that the distal sections of the fork can touch, thus generating a substantially closed bag-shaped sail. 
       FIG. 3A  shows a configuration of the profiling devices  40  corresponding to the maximum thickness of the profile, while  FIG. 3B  shows the configuration with a minimum thickness. 
     The configuration  3 B of minimum distance between the battens  41  and  42  could for example correspond to a resting state, and  FIG. 3B  to an elastic deformation state of the batten  45 . 
     To adjust the thickness of the aerodynamic profile, it is possible to use a member  51  which slides between the portions of the fork facing each other, as indicated by the arrows R. 
     When the sliding member  51  is in the position of  FIG. 3A  it causes an expansion of the fork, while in the position of  FIG. 3B  it allows the fork to elastically return to the resting state with minimum thickness. 
     In addition to or as an alternative to the expansion, the effect of the sliding member  51  could be that of elastically deforming at least one of the sections  41  and  42 . 
     This is possible, for example, when both ends of the section to be deformed are at least partly constrained. For example, one of the two ends could be constrained only to sliding movement with respect to the batten section facing it. 
     The hooking of the sail  20  to the mast  25  preferably takes place by means of hooking elements  55  coupled to the proximal sections  43  of the profiling devices  40 . The mast preferably defines a sliding guide for these hooking elements  55  to allow the sail  20  to be raised or lowered. The hooking elements  55  are for example T-shaped elements sliding in a complementary groove  56  of the mast  25 . 
     Referring again to  FIG. 1 , the sail is also able to rotate at least in part around the main extension axis X of the mast  25 . In order to achieve this controlling manoeuvre, it is possible, for example, to adopt a control cable  60  coupled to one or more profiling devices  40 , so that they have a boom function. For example, the control cable  60  has one end  61  coupled to the mast  25 , a free end  62  which can be grasped by an operator and can be fixed to the hull, and a coupled and slidable intermediate portion  63  with at least one batten  45 , such to shorten the length of the cable between the end  61  and the fixing point to the hull, and the inclination of the sail is increased or decreased. 
       FIG. 1  also makes it possible to appreciate a particularly preferred embodiment wherein the mast  25  is U-shaped, comprising two main sections  70  which are side by side and an intermediate section  71  for joining the two. The mast  25  thus defines a U-shaped sliding guide which allows the sail to be displaced between two mirrored positions, one wherein it, or its main part, is located at one of the two main sections  70 , and the other wherein it is located at the other section. 
     In use, after the sail  20  has been raised on the mast  25 , it has a resting configuration of the profiling devices  40  corresponding to the minimum aerodynamic thickness of  FIG. 3B . This is at least due to the elastic action of the proximal section  43  of the battens  45  and the inoperability of the sliding member  51 . The thickness of the aerodynamic profile is then adjusted by moving the sliding member in opposition to said elastic action, as shown in  FIG. 3A . This operation causes a distancing of the distal sections  41  and  42  of the battens  45  corresponding to larger thickness configurations. 
     In order to reduce the thickness again, also up to returning to the resting configuration, the sliding member  51  must be retracted to the position in  FIG. 3B . 
     The example cited therefore represents the general functional concept of the sliding member for adjusting the profile through an expanding thrusting action of the fork. 
     With reference to the following figures, other embodiments and variants of the invention are shown where equal or similar elements are indicated with the same reference numbers used above, or with the same numbers incremented by 100, or a multiple thereof. 
       FIG. 4  shows a wind propulsion system  101  which differs from the system  1  of  FIG. 1  mainly in that the vessel  105  has a traditional-type mast  125 , i.e. with a single vertical section along which the sail  20  slides to be raised and lowered, without the possibility of overturning its orientation. 
     In this case, the rig  115  comprises a real, traditional-type boom  65  controlled by the control cable  60 . 
     The shape of the aerodynamic profile is always changed through the sliding member  51 . 
       FIGS. 5 and 6  show, by way of example, an embodiment which adopts layers  36  and  37  of equal or substantially equal extension, and therefore in general profiling devices  40  with distal sections  41  and  42  of equal or substantially equal length. Substantially equal values are intended as two values whose difference does not exceed 10% of the greater value. 
     Of course, it is not excluded that the rig  115  has layers  36  and  37  with a markedly different extension from each other, as in the examples of  FIGS. 1 and 2 . 
     With reference to  FIGS. 7A and 7B , an alternative profiling device  40  is shown which differs from those of the previous figures mainly in that the distal batten sections  41  and  42  form respective movable jaws with respect to each other thanks to a joint  43  (e.g. a rotation joint) placed at one of their ends coinciding with the edge  38   a  of the sail. 
     The joint  43  is moved by the sliding of the member  51 , which is wedged between the batten sections. This is able to spread the sections  41  and  42 . The case is also envisaged wherein only part of the sections  41  and  42  spread, in the case wherein one or both have ends opposite the constrained joint  43 . The example of  FIGS. 7A and 7B  shows the latter eventuality, where the short section  42  has the greatest deformation, which is created with less rigidity than the long section  41 . 
     The consequence is a variation in the concavity of the aerodynamic profile, since the section  42  passes from being concave to convex, or rather mainly concave, as in  FIG. 7B , to mainly convex, as in  FIG. 7A , due to the persistence of connecting sections with opposite curvature. 
     In the use of the embodiments wherein the batten sections  41  and  42  are joined to each other, they preferably have a resting position corresponding to their minimum distance wherein they oppose their distancing, for example due to the effect of elastic means. The latter can be, for example, the battens themselves, in the case wherein at least one is elastic and is joined to the other at both ends, as in the example of  FIGS. 7A and 7B , or other elastic means interposed between the joined sections  41  and  42 , such as for example a fork spring in the joint  43 . 
     With reference now to  FIGS. 6A to 6C , an embodiment of the profiling device is shown wherein the batten sections  41  and  42 , when at rest, are in the maximum expansion configuration of the fork, and the profile is adjusted through pulling means  50  which bring them together by reducing the expansion. The pulling means  50  comprise, for example, a pulling cable. 
     Also in this case it is possible to adopt the sliding member  51 , but its action is to limit the minimum expansion that can be achieved. Depending on its position, in fact, the sections  41  and  42  can be brought more or less close to each other. This can be advantageous in the event of strong winds, as it prevents the latter from closing the profile more than desired. 
     It can be observed that the sliding member, thanks to its movement, regulates the minimum obtainable thickness. 
     It is to be understood that the sliding member  51  can be replaced by any other member for limiting the minimum thickness. For example, it is possible to adopt fixed limiting members, such as reference stops lacking relative movement with respect to the battens, or cams which regulate the minimum thickness by rotating rather than sliding. An example of the latter case is given in  FIGS. 8A and 8B , where the cam is indicated with number  80 . 
     General Interpretation of Terms 
     In understanding the object of the present invention, the term “comprising” and its derivatives, as used herein, are intended as open-ended terms that specify the presence of declared characteristics, elements, components, groups, integers and/or steps, but do not exclude the presence of other undeclared characteristics, elements, components, groups, integers and/or steps. The above also applies to words that have similar meanings such as the terms “comprised”, “have” and their derivatives. Furthermore, the terms “part”, “section”, “portion”, “member” or “element” when used in the singular can have the double meaning of a single part or a plurality of parts. As used herein to describe the above executive form, the following directional terms “forward”, “backward”, “above”, “under”, “vertical”, “horizontal”, “below” and “transverse”, as well as any other similar directional term, refers to a sail deployed in a use configuration. Finally, terms of degree such as “mainly”, “about” and “approximately” as used herein are intended as a reasonable amount of deviation of the modified term such that the final result is not significantly changed. 
     While only selected embodiments have been chosen to illustrate the present invention, it will be apparent from this description to those skilled in the art that various modifications and variations can be made without departing from the scope of the invention as defined in the appended claims. For example, the size, shape, position or orientation of the various components can be modified as needed and/or desired. The components shown which are directly connected or in contact with each other can have intermediate structures arranged between them. The functions of an element can be performed by two or more and vice versa. The structures and functions of one embodiment can be adopted in another embodiment. All the advantages of a particular embodiment do not necessarily have to be present at the same time. Any characteristic that is original compared to the prior art, alone or in combination with other characteristics, should also be considered a separate description of further inventions by the applicant, including the structural and/or functional concepts embodied by such characteristics. Therefore, the foregoing descriptions of the embodiments according to the present invention are provided for illustrative purposes only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents. 
     Furthermore, we reserve the right to remove (disclaimer) everything that is revealed as prior art during the patent examination procedure.