WO2006090425A2

WO2006090425A2 - Clamping device to removably constrain a boom to the mast of a sailboard

Info

Publication number: WO2006090425A2
Application number: PCT/IT2006/000098
Authority: WO
Inventors: Rossano Corso del Popolo 98 I - 30028 S. MlCHELE AL TAGLIAMENTO BISIOLI
Original assignee: Itallca Spa
Priority date: 2005-02-24
Filing date: 2006-02-23
Publication date: 2006-08-31
Also published as: WO2006090425A3; EP1755941A2

Abstract

Device (10) to constrain a boom (19, 20) to a mast (15) of a sailboard. The mast (15) comprises an outer surface in correspondence with which two ends (19a, 20a) of the boom (19, 20) are disposed. The device (10) comprises constraining elements (23) able to couple each of the ends (19a, 20a) of the boom (19, 20) to the outer surface of the mast (15), so that an axis (X) joining the two ends (19a, 20a) also intersects the mast (15).

Description

"CLAMPING DEVICE TO REMOVABLY CONSTRAIN A BOOM TO THE MAST

OF A SAILBOARD" * * * * *

FIELD OF THE INVENTION The present invention concerns a clamping device to constrain, also temporarily and removably, a boom to the mast of a sailboard used for practicing windsurfing

BACKGROUND OF THE INVENTION

Sailboards for practicing windsurf are known, each of which has a mast, made of composite material, for example carbon, with a height comprised between about 3 and about 6 meters, and attached to the board by means of an articulated joint.

The sail or spanker is inserted on the mast, and defines the trim of the board in cooperation with a boom, attached in turn to the mast and used to orientate the sail with respect to the mast.

To insert the sail on the mast, to remove it from the mast and to facilitate the transport and storage of the sailboard, the boom is tightened to the mast by means of a removable clamp element.

A clamping device is known which comprises a pair of opposite jaws, which are associated with the two ends of the boom and are pulled one against the other in order to close vice-like against the outer surface of the mast.

This known clamping device, however, has the disadvantage that it does not allow a precise and controlled adjustment of the tightening force applied. Moreover, it may happen that, if tightened too much to the mast, the two jaws prevent the mast from bending without a break in continuity along its entire length.

One purpose of the present invention is to achieve a clamping device to removably constrain a boom to the mast of a sailboard, which is simple to assemble and to use, and which at the same time, once assembled, will achieve a perfect clamping of the boom to the mast, substantially without preventing the mast from bending even in the constraint zone.

Another purpose of the present invention is to achieve a clamping device which will achieve a very tight and rigid constraint of the boom and the mast, so that the user, when maneuvering the boom, can transmit his maneuver commands to the mast and can obtain an immediate response from the board to these commands, and that the performance of the sailboard in general is improved, especially in bowline conditions .

The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages .

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the main claims, while the dependent claims describe other characteristics of the invention or variants to the main inventive idea.

In accordance with the above purposes, a clamping device according to the present invention is used to constrain a boom to the mast of a sailboard of the type used to practice windsurfing.

The mast comprises a constraint zone, defined by a portion of its outer surface, and the boom comprises at least two ends able to be coupled in correspondence with the constraint zone of the mast, by means of constraining means, so that a transverse axis "X" joining the two ends of the boom intersects the mast, advantageously in a manner substantially orthogonal to a longitudinal axis "Y" of the mast .

In this way, the two ends of the boom are constrained directly to the mast by means of the constraining means, thus guaranteeing that the boom-mast connection is extremely rigid and that the maneuver commands, given by the user on the boom, are transmitted to the mast much more immediately and precisely with respect to known solutions, and therefore allowing the sailboard to be governed better and more easily. According to a characteristic of the present invention, said constraining means comprises:

- a support element able to be disposed substantially coaxial with said constraint zone;

- at least two clamping elements disposed on substantially opposite sides with respect to the longitudinal axis of the mast, each of which is coupled autonomously with said support element in order to be thrust by a thrust element against the outer surface of the mast, and is connected to one of the two ends of said boom. Advantageously, said support element is disposed with play around the mast and does not interfere with it.

Moreover, advantageously, the two clamping elements comprise two jaws and the support element comprises a ring, which can be made of metal material, carbon fiber or other very resistant material, with which two drawing elements are coupled, disposed on substantially opposite sides with respect to the longitudinal axis of the mast, and on which said thrust elements are able to discharge their force.

It comes within the field of protection of the present invention to provide that the support element consists of two rigid parts, diametrically opposite and connected to each other by one or more drawing elements which limit their radial extension. In this way, the support element keeps the drawing elements separated from the mast, so that the clamping elements are the only parts that press laterally against the outer surface of the mast, in the constraint zone, thus determining, precisely, the constraint of the boom to the mast and leaving the latter free to bend on a plane passing through the longitudinal axis Y of the mast and substantially perpendicular to the transverse axis X joining the two ends of the boom.

The solution according to the present invention thus allows the mast a greater and natural flexion and elastic reaction, extending the duration and improving the performance thereof.

Another advantage is given by the fact that the device according to the present invention advantageously also allows to assemble asymmetrical booms to the mast, something which is not possible with many of the vice-type clamping devices of a known type.

In a first form of preferential embodiment, the drawing elements consist of two threaded stud bolts coupled with the support element, and the thrust elements consist, for example, of two threaded ring-nuts, blocks or nuts, coupled therewith by screwing.

In a second form of preferential embodiment, the drawing elements consist of two pins connected to the support element, and on which a thrust lever is pivoted, which with its rotation exerts an axial and centrifugal traction on the pins.

The direct assembly of the boom to the mast is substantially facilitated for the user, and it has the advantage that it makes the sailboard more easily governed, since it is not necessary to use clamps, or handles or other relatively heavy clamping mechanisms.

Moreover, according to the present invention, protruding clamp elements are eliminated which displace the baricenter of the boom-mast system towards the front of the sailboard. Moreover, because the ends of the boom are connected directly to the mast, the boom used according to the present invention, given the same characteristics as known booms, is at least 10 cm shorter, therefore having greater rigidity.

According to another characteristic of the invention, the device comprises at least a guide element applied directly on the mast and defining at least an attachment seating with which a clamping element associated with the boom is selectively able to be coupled. The guide element is made solid with the structure of the mast and integrated therewith so as to define a substantially single body, or is made integral with a sleeve coupled axially and outside the mast.

According to a variant of the invention, the attachment seating extends parallel to the mast for a certain length, so as to allow the adjustment of the height of the clamping element and hence of the height of the boom, for example, according to the height of the user.

Advantageously, the solution that provides the sleeve allows to attach the sleeve to the mast at any desired height, which allows a further adjustment of the height of the boom irrespective of the length of the seating.

According to an advantageous solution, the attachment seating or seatings of the boom are located on the face of the mast that faces towards the stern of the sailboard, or to port or starboard, so that the face of the mast facing towards the front is free and without protrusions and the baricenter of the mast-sail-boom system is displaced towards the stern.

According to one embodiment of the invention, the attachment seating comprises guide means that extends longitudinally with respect to the mast, and the clamping element comprises screw means cooperating with mating threaded holes made at various heights on at least a bottom wall of the guide means itself, or, according to a variant, with at least a platelet inserted in the guide means and in turn cooperating with the outer walls of the guide means.

According to another variant, the clamping element can be constrained to the guide by means of snap-in clamping means, or interference, which cooperate internally and/or externally with the walls of the guide.

According to another variant, the attachment seating comprises one or more supports on each of which at least a threaded hole is made, with which in turn a mating screw is able to be screwed, cooperating with the clamping element.

According to the invention, in a first step, the two ends of the boom are associated with the mast so that the axis

"X" joining the two ends of the boom intersects the mast too, and in a second step the two ends of the boom are constrained to the mast by means of the constraining means.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other characteristics of the present invention will become apparent from the following description of a preferential form of embodiment, given as a non-restrictive example with reference to the attached drawings wherein:

- fig. 1 is a lateral view of a sailboard using the device according to the invention; -'fig. 2 is a section of the sailboard from II to II of fig. 1; - fig. 3 is an enlarged view of the device in fig. 1, in an exploded condition;

- fig. 4 is an enlarged view of the device in fig. 3 in an assembled condition; - fig. 5 is a part section along the line from V to V of fig. 4;

- fig. 6 is a first variant of the device in fig. 3;

- fig. 7 is a second variant of the device in fig. 3; - fig. 8 is a partly sectioned lateral view of a third variant of the device in fig. 1;

- fig. 9 is a plane section of the device in fig. 8;

- fig. 10 is a partly sectioned lateral view of a variant of the device in fig. 8; - fig. 11 is a plane section of the device in fig. 10;

- fig. 12 is a lateral view of another variant of the device in fig. 8;

- fig. 13 is a plane section of another variant of the device in fig. 8; - fig. 14 is a section of a detail of the device in fig. 13;

- fig. 15 is a lateral section of a detail of fig. 13;

- fig. 16 is a plane section of a variant of the device in fig. 13. DETAILED DESCRIPTION OF A PREFERENTIAL FORM OF EMBODIMENT With reference to fig. 1, a device 10 according to the present invention is used in a sailboard 11 of the type used for practising windsurfing, in order to constrain a boom 18 to a mast 15. The sailboard 11 (figs. 1 and 2) comprises a plane or board 13 itself, which has an articulated joint 14 to which the base of the mast 15 is constrained.

The mast 15 has a tubular section, a height comprised between about 3 and about 6 meters, and is made of composite material, for example carbon, fiber glass or other material with equivalent characteristics of resistance to stresses and flexibility. A sail 16 is able to be inserted on the mast 16. The boom 18 (fig. 2) is substantially oval in shape and is able to be constrained, at least temporarily, to the mast 15 in correspondence with a constraint zone 22.

The boom 18 consists of two transverse elements 19 and 20, substantially symmetrical and consisting in turn of coupling tubular elements of a known type, able to be detached from each other to facilitate the transport and storage of the sailboard 11.

The two transverse elements 19 and 20 are joined together in correspondence with a respective end which, during use, is facing towards the front of the sailboard 11, to which end the sail 16 is attached.

According to a first form of embodiment of the present invention, the front end 19a and 20a (figs. 3 and 4) of each transverse element 19 and 20 is rotatably mounted on a ring-nut 24, by means of the male part of a threaded connection 28, of the male/female type attached to the ring-nut 24. The function of each ring-nut 24 will be explained hereafter. The rotatable assembly of the two ends 19a and 20a on the ring-nuts 24 allows the boom 18 to be able to oscillate with respect to a substantially horizontal axis X, which joins the same two ends 19a and 20a and which intersects the longitudinal axis X of the mast 15, making the sail 16 more maneuverable, especially in the operations to orient it with respect to the board 13. This oscillation also allows a greater absorption of the stresses due to the knocks of the board 13 on the waves, without entailing great elastic deformations of the transverse elements 19 and 20 of the boom 18.

The device 10 comprises, in this case, a support ring 23 inserted with play and substantially coaxial around the mast 15, in correspondence with said constraint zone 22. The ring 22 is able to support the heads of two screws 25 which protrude laterally therefrom, in direction of the respective ends 19a and 20a of each transverse element 19 and 20 of the boom 18. In this way, the female part of the threaded element 28 of the corresponding ring-nut 24 can be brought near the corresponding screw 25, which acts as a drawing element, determining the attachment of the boom 18 to the support ring 23. The two screws 25 are radially and rotatably constrained to the support ring 23 by means of respective heads 25a (only one of which is shown in fig. 5) housed in a mating inner circular seating 23a of the support ring 23.

In this way the screwing of the ring-nuts 24 to the screws 25 determines the opposite traction of the latter, keeping the support ring 23 concentric and detached from the mast 15.

To be more exact, the shafts of the two screws 25 protrude from respective eyelets 26, made on diametrically opposite sides on a lateral wall of the support ring 23. The eyelets 26 allow a selective angular orientation of the screws 25, so as to allow the positioning of each transverse element 19 and 20 of the boom 18 in a condition substantially perpendicular to the longitudinal axis Y of the mast 15. More generally, irrespective of the orientation of the respective screws 25, the axis X that joins the two ends 19a and 20a always intersects the mast 15, advantageously in correspondence with the longitudinal axis Y of the latter. The device 10 according to the present invention also comprises two clamping elements consisting of two jaws 27, each having two front surfaces 29 which, in use, contact under pressure the lateral parts of the mast 15 in the constraint zone 22. Each jaw 27 is shaped so as to define a central seating 30 (fig. 3) which allows to house, with play, a corresponding circular portion of the support ring 23. A through hole 31 is open on the central seating 30 and is able to allow the through housing of the corresponding screw 25. Each jaw 27 also comprises a thrust surface 32, substantially opposite the two front surfaces 29 and on which the ring-nut 24 is able to act due to the effect of its screwing on the screw 25. Each jaw 27 is advantageously made of a self-lubricating polyurethane material, such as for example Teflon® or suchlike, while the front surfaces 29 are made of a material with a high friction coefficient, such as for example synthetic rubber, natural rubber or other. The device 10 as described heretofore is assembled as follows .

Firstly, the support ring 23, provided with the respective screws 25, is inserted coaxially on the mast 15, until it is disposed in the constraint zone 22. Then the two jaws 27 are disposed so that the respective front surfaces 29 are in contact with the opposite lateral parts of the constraint zone 22, and so that the screws 25 emerge from the through holes 31.

Then the ring-nuts 24 are screwed to the screws 25, so that their progressive screwing determines a pressure on the thrust surfaces 32 of the respective jaws 27, and consequently a pressure of the front surfaces 29 against the constraint zone 22 of the mast 15, thus determining the effective constraint of the boom 18 to the mast 15. According to the form of embodiment shown in fig. 6, instead of the two ring-nuts 24 two clamping nuts 124 are provided, disposed inside the respective transverse elements 19 and 20 of the boom 18 and able to be screwed to - li ¬

the screws 25 in order to determine the thrust, in this case effected directly by the ends 19a and 20a on the corresponding thrust surfaces 32 of the jaw 27.

In the embodiment shown in fig. 7, with the end 19a and 20a of every transverse element 19 and 20 a cam-type clamping lever 224 is associated, for example of the type similar to those used for the removable clamping of bicycle hubs. In this way, a rotation of the clamping lever 224 around a pivoting axis determines the constraint of the boom 18 to the mast 15. In the embodiment shown in fig. 7, instead of the screws 25 two drawing pins 225 are provided, to the outer ends of which the corresponding clamping levers 224 are pivoted.

Thanks to the present invention, the coupling of the mast 15 and the boom 18 is extremely stable and allows the user a better control of the sailboard 11 with respect to known solutions. Moreover, the device 10 has a lesser weight with respect to known solutions.

It also comes within the field of the present invention to provide that instead of the support ring 23 two or three rigid elements may be provided, disposed separate and diametrically opposite the mast, which limit the radial extension of the two screws 25 or of the two drawing pins 225. According to another form of embodiment of the invention, as shown in figs. 8 and 9, the end 19a, 20a of each transverse element 19 and 20 is inserted in a seating 324 made in a respective clamping element 323 and is clamped thereto in a known manner, for example by screwing, interference, riveting or is attached by gluing.

Two screws 325 are attached to the mast 15 in its constraint zone 22, and are disposed radial, on diametrically opposite sides, and substantially orthogonal with respect to the outer surface of the mast 15, at the same height with respect to the board 13.

Each clamping element 323 comprises a head 326 which has a through hole 327 in which the respective screw 325 can be inserted, and which defines a compartment 328 accessible from outside in order to allow the user to screw a nut 330, cooperating with the inner surface of said compartment 328, onto the respective screw 325, in order to constrain the clamping element 323, and hence the transverse element 19, 20 of the boom 18, to the mast 15.

It is provided that the two screws 325 can be disposed at different heights with respect to each other and to the board 13, and oriented with respect to each other by an angle even other than 180°. According to the variant shown in figs. 10 and 11, the device according to the present invention comprises a ring 332 made of metal, plastic material or composite material, for example carbon, having an inner diameter equivalent to that of the mast 15, on which it is inserted. In the body of the ring 332 two screws 333 are attached, diametrically opposite, or oriented with respect to each other by a desired angle. The head 326 comprises two protruding blocks 334 defining a seating 336, of size and shape mating with the width and thickness of the ring 32. The protruding blocks 334 are covered with elastomer material, for example rubber, able to allow an effective coupling with the outer surface of the mast 15.

In this case too the nut 330 of each screw 333 is screwed to constrain the clamping element 323 to the mast 15. According to the variant shown in fig. 12, the ring 332 is replaced by a pair of rings 337a and 337b, disposed concentric and free to rotate one with respect to the other, allowing to use booms 18 having the ends 19a, 20a oriented with different angles.

According to a variant not shown here, the two rings 337a and 337b are not only able to be oriented with respect to each other, but also can be reciprocally distanced, thus allowing to use asymmetric booms 18 too.

According to the variant shown in figs. 13, 14 and 15, each transverse element 19 and 20 comprises a seating 424 at the respective ends 19a, 20a, the use of which will be explained later. According to one embodiment, a device 400 according to the present invention comprises two longitudinal guide elements 425, made solid with the outer surface of the mast 15 in correspondence with the constraint zone 22 so as to define a substantially single body with the mast 15. The guide elements 425 are disposed, in the preferential embodiment, on two opposite faces which, during use, face respectively port and starboard of the board 13, and each defines a sliding channel 442 having a length comprised, for example, between about 1 cm and about 60 cm. To be more exact, the solution with the channel 442 with a minimum length concerns a personalized application adjusted to the height of the single potential user, while the solutions with greater lengths allow a wide range of adjustment of the point of constraint for occasional users. The device 400 also comprises two clamping elements 423, each of which is able to cooperate with one of the two guide elements 425 and has a body 428, at one end of which a pin 429 branches off and at the other end of which a supporting plate 431 is disposed. The pin 429 is able to be inserted in the seating 424 of the corresponding transverse element 19 or 20 in order to constrain the boom 18 to the clamping element 423, for example by means of a snap-in closure of the type comprising a button 432 associated with a spring 433 as shown schematically in figs. 14 and 15.

The supporting plate 431, which is able to be disposed in contact with the outer surface of two walls 440 of the respective guide element 425, comprises a through hole 439 whose longitudinal axis, in use, is substantially orthogonal to said outer surface and in which a screw 438 is able to be inserted. The body 428 also comprises a compartment 441 (fig. 14) which allows to access the screw 438 or its head from outside.

The clamping element 423 also comprises a platelet 434 inserted inside the channel 442 of the respective guide element 425, free to slide longitudinally therein, in cooperation with the inner surface of the two walls 440 of the relative channel 442.

The platelet 434 has a threaded hole 437 which branches off radially with respect to the mast 15 and to which the screw 438 is able to be screwed, so that the supporting plate 431 and the platelet 434 are facing each other and kept distanced by the two walls 440.

When the screw 438 is screwed into the threaded hole 437, the supporting plate 431 and the platelet 434 are held thrust against each other and clamped to the channel 442 of the relative guide element 425 by interference with the two walls 440, so as to clamp the clamping element 423 to the mast 15.

By partly unscrewing the screw 438, it is possible to move the clamping element 423 vertically with respect to the guide element 425, allowing to vary the height of the boom 18 with respect to the board 13 according to the height of the user.

Finally, by completely unscrewing the screw 438, it is possible to remove the clamping element 423, releasing it from the mast 15.

Thanks to the invention, the coupling of the mast 15 and the boom 18 is extremely stable and allows the user a better control of the sailboard 11 with respect to known solutions. Moreover, the device 400 has a lesser weight with respect to known solutions .

According to a variant shown in fig. 16, the device 400 comprises only one guide element 425 and only one mating clamping element 423, and the pin 429 is inserted in a seating 424 made directly at one end of the boom 18.

It also comes within the field of the invention to use more than one screw 438 and therefore an equal number of holes 437 and 439 to constrain the clamping element 423 to the platelet 434 and to the guide element 425. According to another variant, it is provided to make a threaded hole on the bottom wall of the guide element 425, on which the screw 438 is able to be screwed, thus further improving the clamping.

According to another variant, it is provided to make a plurality of threaded holes on the bottom wall of the guide element 425, disposed at different heights, to one of which the screw 438 is able to be screwed, allowing to adjust the height of the boom 18.

According to another variant, the guide element 425 is made on a sleeve able to be applied and attached in a known manner, for example by means of glue, on the mast 15.

According to another variant not shown, instead of the guide elements 425 it is provided to make one or more plate-type supports solid with the mast 15, each one equipped with at least a threaded hole to which a mating screw is able to be screwed, cooperating with the clamping element 423, for example in the manner described heretofore . In order to make the guide element 425 or the support solid with the mast 15, it is provided to attach to the latter a plate, for example made of Teflon, to which the guide element 225 or the support itself is subsequently screwed.

It is clear that modifications and/or additions of parts may be made to the devices as described heretofore, without departing from the field and scope of the present invention. It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of clamping devices to removably constrain a boom to the mast of a sailboard, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

Claims

1. Clamping device to removably constrain a boom (18) to a mast (15) of a sailboard (11), wherein said mast (15) comprises a constraint zone (22) defined by a portion of its outer surface, wherein said boom (18) comprises at least two ends (19a, 20a) able to be coupled in correspondence with said constraint zone (22) of said mast (15), so that a transverse axis (X) joining said two ends (19a, 20a) intersects said mast (15), and wherein constraining means is provided in order to removably couple each of said ends (19a, 20a) of said boom (18) to said outer surface (22) of said mast (15), characterized in that said constraining means comprises a support element (23, 323) able to be disposed substantially coaxial with said mast (15) in said constraint zone (22), and two clamping elements (27, 334) disposed on substantially opposite sides with respect to a longitudinal axis (Y) of said mast (15), each of which is coupled autonomously with said support element (23, 332) in order to be thrust by a corresponding thrust element (24, 124, 224, 330) against said constraint zone (22), and is connected to one of said two ends (19a, 20a) of said boom (18).

2. Device as in claim 1, characterized in that said support element (32) is disposed around said mast (15) substantially without interfering with it.

3. Device as in claim 1 or 2, characterized in that each of said clamping elements comprises a jaw (27).

4. Device as in any claim hereinbefore, characterized in that said support element comprises an annular element (23, 332) with which two drawing elements (25, 225, 333) are coupled, disposed on substantially opposite sides with respect to a longitudinal axis (Y) of said mast (15) and on which said thrust elements (24, 124, 224, 330) are able to discharge their force.

5. Device as in claim 4, characterized in that said support element (23) comprises, on diametrically opposite sides, two eyelets (26) from each of which emerges a corresponding one of said drawing elements (25, 225), so as to allow the selective radial orientation of said drawing elements (25, 225).

6. Device as in claim 4 or 5, characterized in that said drawing elements comprise two screws (25, 333) radially constrained to said annular element (23, 332).

7. Device as in claim 4 or 5, characterized in that said drawing elements comprise two pins (225) radially constrained to said annular element (23).

8. Device as in claim 3, characterized in that each of said jaws (27) comprises at least a front surface (29) able to contact said outer surface (22) of said mast (15), and a thrust surface (32), substantially opposite said front surface (29) and on which said thrust exerted by said corresponding clamping element (24, 124, 224) is able to be exerted.

9. Device as in claim 8, characterized in that each of said thrust elements comprises a ring-nut (24) which on one side is rotatably connected to one of said ends (19a, 20a) of said boom (18), and on the other side is screwed to one of said screws (25) and contacts one of said jaws (17) in order to thrust it against said mast (15).

10. Device as in claim 8, characterized in that each of said thrust elements comprises a threaded nut (124) screwed to one of said screws (25) and disposed substantially inside said boom (18), in correspondence with one of said ends (19a, 20a) in order to thrust said end (19a, 20a) against the corresponding jaw (27).

11. Device as in claim 10, characterized in that each of said thrust elements comprises a lever (224) pivoted on a pin (225) and disposed substantially inside said boom (18), in correspondence with one of said ends (19a, 20a), so that the rotation of said lever (224) determines the centrifugal traction of said pin (225) and effects a thrust against the corresponding jaw (27).

12. Clamping device to removably constrain a boom (18) to a mast (15) of a sailboard (11), wherein said mast (15) comprises a constraint zone (22) defined by a portion of its outer surface, wherein said boom (18) comprises at least two ends (19a, 20a) able to be coupled in correspondence with said constraint zone (22) of said mast (15), so that a transverse axis (X) joining said two ends (19a, 20a) intersects said mast (15), and wherein constraining means is provided in order to removably couple each of said ends (19a, 20a) of said boom (18) to said outer surface (22) of said mast (15), characterized in that said constraining means comprises screw means (325) attached directly on said mast ( 15 ) on opposite sides with respect to a longitudinal axis (Y) of said mast (15).

13. Device to constrain a boom (18) in correspondence with a constraint zone (22) of a mast (15) of a sailboard (11), characterized in that it comprises at least a guide element (425) applied in correspondence with said constraint zone (22) and defining an attachment seating (442) with which a clamping element (423) associated with said boom (18) is able to be selectively coupled.

14. Device as in claim 13, characterized in that said guide element (425) defining said attachment seating (442) is made solid with said mast (15).

15. Device as in claim 13, characterized in that said guide element (425) is made on a sleeve, which is able to be coupled axially and outside said mast (15) at a determinate height .

16. Device as in any claim from 13 to 15, characterized in that said attachment seating (442) extends vertically along said mast (15) for a certain amplitude.

17. Device as in any claim from 13 to 16, characterized in that said clamping element (423) comprises at least a supporting plate (431) cooperating with an outer surface of a wall (440) of said attachment seating (442) and at least a corresponding platelet (434) inserted in said attachment seating (442) and cooperating with an inner surface of said wall (440), wherein said supporting plate (431) and said platelet (434) are held thrust against said wall (440) by at least a screw (438) to constrain said clamping element (423) to said constraint zone (22).

18. Device as in claim 17, characterized in that in a bottom wall of said attachment seating (442) opposite said wall (440) at least a threaded hole is made, to which said screw (438) is able to be attached.

19. Device as in any claim from 13 to 15, characterized in that said guide element (425) comprises one or more longitudinal supports on each of which at least a threaded hole is made, able to accommodate a mating screw cooperating with said clamping element (423) in order to constrain said clamping element (423) to said constraint zone (22).

20. Device as in any claim from 13 to 15, characterized in that it also comprises a plate, made of Teflon® or of similar material, which is able to be attached to said constraint zone (22) and on which said guide element (425) is able to be screwed.

21. Device as in any claim from 13 to 15, characterized in that said clamping element (423) comprises snap-in clamping means cooperating with said attachment seating (442) in order to constrain said clamping element (423) to said constraint zone (22).

22. Boom for a sailboard (11) provided with a mast (15) having an outer surface, wherein said boom comprises at least two ends (19a, 20a) able to be disposed in correspondence with said mast (15), characterized in that constraining means (23, 323, 423) is able to couple each of said ends (19a, 20a) of said boom (18) to said outer surface of said mast (15), so that an axis (X) joining said two ends (19a, 20a) also intersects said mast (15).

23. Mast for a sailboard (11) having a boom (18) wherein said mast ( 15 ) comprises an outer surface and wherein said boom (18) comprises at least two ends (19a, 20a) able to be disposed in correspondence with said mast (15), characterized in that constraining means (23, 323, 423) is able to couple each of said ends (19a, 20a) of said boom (18) to said outer surface of said mast (15), so that an axis (X) joining said two ends (19a, 20a) also intersects said mast (15) .

24. Sailboard comprising a mast (15) having an outer surface, and a boom (18) having at least two ends (19a, 20a) able to be disposed in correspondence with said mast (15), characterized in that it comprises constraining means (23, 323, 423) able to couple each of said ends (19a, 20a) of said boom (18) to said outer surface of said mast (15), so that an axis (X) joining said two ends (19a, 20a) also intersects said mast (15).

25. Method to connect a boom (18) of a sailboard (11) to the relative mast (15), characterized in that it comprises a first step wherein at least two ends (19a, 20a) of said boom (18) are associated with said mast (15) so that an axis (X) joining said two ends (19a, 20a) also intersects said mast (15), and a second step wherein the two ends (19a, 20a) of said boom (18) are constrained to said mast (15) by means of constraining means (23, 323, 423).