CONTINUOUS LAMINATION PROCESS OF SAILING BOAT MASTS AND THE PRODUCT OBTAINED THUS

Description

PRAXI Intellectual Property SpA PF / GZ / 134p2023 Description of the invention entitled: “CONTINUOUS ROLLING PROCESS OF TREES OF SAILING BOATS AND THE PRODUCT OBTAINED THUS” in the name of: MAXSPAR SRL to: Genoa (GE) Inventor: FRANCHETTI Enrico ________________________________________________________________ Description Field of technology The invention refers to an innovative process for rolling wood shafts. composite sailing vessels, which are distinguished from the prior art by their high resistance to torsional load thanks to the absence of gluing, given their unique and continuous structure, possible only thanks to the creation of a constant thickness of the laminate which characterises the entire section of these trees. Known art The construction of a sailing vessel's mast, especially when one is refers to a racing and cruising vessel, reveals a process that combines advanced technology, precision craftsmanship and a deep understanding of the materials. Every stage, from design to manufacturing, requires attention to details and specialist skills to ensure a final product that is light, resistant and capable of significantly improving the performance of the vessel. The process begins with a meticulous design phase, where engineers determine the exact specifications of the mast based on the needs of the boat and the expected navigation conditions. Using computer-aided design software From FEM computers, three-dimensional models are created which allow simulate the stresses and optimize the distribution of the material along the tree to maximize performance and safety. Once the design is complete, we move on to selecting the materials. PRAXI Intellectual Property SpA PF / GZ / 134p2023 If carbon fiber is chosen, due to its high mechanical resistance and the its low specific weight, this realization must be done using carbon pre-impregnated which, once polymerized, gives the composite a rigidity exceptional. The quality of the carbon fiber and resins is crucial, as variations in material properties can significantly affect the performance and durability of the shaft. The manufacturing phase begins with the preparation of the male or female mold female, which determines the final shape of the tree. These molds can be made of metal or reinforced composite materials to ensure maximum precision and dimensional stability. Subsequently, the carbon fiber layers are placed in the molds following precise rolling sequences. Each layer must be carefully arranged to ensure that the fibres are oriented correctly and that the resin penetrates evenly through the fabric. Once all the layers are in place, the assembly goes through a process vacuum polymerization in an autoclave. This technique consists of applying uniform pressure over the entire surface of the shaft to eliminate any air bubbles and ensure perfect adhesion between the carbon fibers and the resin. vacuum, combined with the application of controlled heat, allows the resin to polymerize, transforming the material from a fluid state to a solid structure and very rigid. After curing, the tree is removed from the mold and assembled, by assembling the accessories that complete it. The surface is then smoothed, if the tree was made with molds male, to reduce aerodynamic drag and improve aesthetic appearance. Finally, protective coatings are applied to increase wear resistance. and to atmospheric agents. However, in the current state of the art, the use of two is completely inefficient. molds to make a single tree, consequently using a glue PRAXI Intellectual Property SpA PF / GZ / 134p2023 to obtain the final artifact. The most commonly used construction currently differs from the one described above in the use of female molds, which require a mating glue longitudinal or lateral to assemble the two parts resulting from the molds, creating a mechanical critical point. The female mold technology was verified with FEM analysis in joint areas and demonstrated that the male mold technology provides greater torsional strength and longevity over time. In fact, this gluing constitutes the most fragile part of the tree. Even patent JP2023064055, published on May 10, 2023, does not solve the problems mentioned above as it claims the description of a material particularly suitable for lamination in the nautical sector, without in any way way to remedy the structural and torsional resistance of trees that are commonly composed of two pieces joined and glued together. The aim of the patent is therefore to reveal a process for creating a mast for sailing boats, using continuous composite material fibres, obtaining a constant thickness of the laminate and therefore a single piece, eliminating the need to glue two complementary pieces. Description of the invention According to the present invention, a rolling process is carried out continuous mast construction for sailing boats that effectively solves the problems above. The continuous rolling process for the construction of boat masts sail is distinguished by the ability to create a mast with a uniform thickness along its entire section, thus minimising bending and twisting during the navigation. This process uses a continuous fiber arrangement technique, following a fixed ratio that involves the use of 80% unidirectional fabrics arranged at 0°, PRAXI Intellectual Property SpA PF / GZ / 134p2023 along the longitudinal axis of the tree, and 20% of biaxial tissues arranged at + / - 45°, overlapping to create continuity in the fibres. These fibers are wrapped around a male mandrel, which defines the shape and the internal volume of the shaft. This lamination process begins with the analysis of the customer's requests, which vary according to the type of vessel, whether it is for racing or intended for cruise. These requests are examined to identify the loads to which the tree will be submitted during navigation. The mandrel is prepared to laminate the layers of fibres that will form it the final thickness of the shaft. The dimensions of the mandrel are designed to vary in based on the total length of the tree. Subsequently, a plurality of fabrics with unidirectional fibres are arranged continuous at 0° with respect to the longitudinal axis. These fibers constitute the majority part of the total thickness of the tree. At the same time, the positioning of the biaxial fabrics on the spindle, oriented at + / -45° along the entire length of the shaft. By way of example but not limited to, all fibres are suitable for pre- impregnated with resin before being placed on the mandrel. Alternatively called fibres are arranged on the spindle when they are still dry, therefore free of resin. To obtain a rigid and torsion-resistant shaft, a biaxial tissue overlap. The length of the overlap is determined by the ratio between the average circumference of the tree and the number of overlaps, established based on the thickness of the tree divided by the thickness of a single layer, multiplied by two. After having wrapped and arranged the fabrics on the mandrel, we proceed with the closing vacuum to ensure uniform and defect-free lamination. The use of an autoclave allows a constant distribution of the resin matrix, limiting PRAXI Intellectual Property SpA PF / GZ / 134p2023 the presence of dry / dry rolling areas. This autoclave is further designed to polymerize the resin by setting in automatically the ideal pressure and temperature. The spindle is then extracted using refrigeration coils that facilitate the detachment of the tissues. This spindle is designed to reduce its section thanks to a system extendable / retractable which brings the external walls closer and further away, reducing the volume during extraction. The spindle, in one embodiment, is made of metal, in order to make the drying of the fibers more effective, given the different characteristics resistive of the metal compared to the composite materials used, minimizing the possibility of deformations occurring in the tree structure. Finally, after having arranged the constraints and hooks for the rigging and halyards, The tree is packaged in a protective casing for transport to the shipyard, where it will be prepared for installation on the customer's vessel. This continuous rolling process guarantees the creation of a tree that can be easily managed in a sporting context, therefore in a regatta, seen its high resistance to the stresses suffered during navigation, thanks to the lack of a junction, which results from a homogeneous distribution of the overlaps. The process which is the subject of the invention is therefore capable of generating a tree consisting of a single piece, having a constant thickness along its entire section, favouring further the creation of a tapering which has the purpose of making the head of the said tree is lighter and more aerodynamic, thus advantageously reducing the heeling moment of the vessel at which the said mast is installed. The advantages offered by the present invention are evident in light of the description. exposed so far and will be even clearer thanks to the attached figures and the detailed description. PRAXI Intellectual Property SpA PF / GZ / 134p2023 Description of the figures The invention will be described below in at least one embodiment. preferred for explanatory and non-limiting purposes with the aid of the attached figures, in which: - FIGURE 1 shows the flowchart underlying this process. continuous rolling, in order to illustrate the plurality of steps that are performed to determine the construction of a mast for sailing boats composed of a single piece, therefore more resistant to the stresses suffered during the navigation. - FIGURE 2 shows the cross-section of a tree obtained using the process of continuous rolling mill object of the invention, for the purpose of illustrating an example of the preparation of the layers of composite material that have been wrapped around the spindle 10. Detailed description of the invention The present invention will now be illustrated by way of example only but non-limiting or binding, using figures which illustrate some embodiments relating to the present inventive concept. With reference to FIG.1, the flow diagram is illustrated which has the purpose of list the steps that make the process being invented efficient and reliable, obtaining a constant final result, which consists of a tree for sailing vessels capable of maintaining a controlled flex, without sagging to the torsion that is typically caused by weather and sea conditions. Said flowchart in more detail includes: - 100% design based on customer requests, based on the type of vessel, whether it is a racing vessel or exclusively used for the sector cruise; the customer's requests being therefore examined and used to identify the loads to which the tree will be subjected during the navigation; PRAXI Intellectual Property SpA PF / GZ / 134p2023 - the 200 predisposition of the mandrel 10, on which the layers will be laminated of fibres suitable for forming the thickness of the final shaft obtained; called mandrel 10 being capable of possessing the dimensions of the internal volume of the shaft, the its dimensions being therefore capable of varying according to the total length of the tree; - the positioning 300 of a plurality of fabrics with unidirectional fibres 11, continue at 0° with respect to the longitudinal axis, above said spindle 10; said unidirectional fabrics 11 being suitable to constitute the majority of the total thickness of the tree obtained with the rolling process continues the subject of the invention; the total number of fabrics 11, 12 to be used is given by the design thickness of the shaft divided by the thickness of a single tissue layer 11, 12; - the arrangement 400 of the biaxial fabrics 12, above said mandrel 10, designed to create a continuity of fibre throughout the tree, using fibres oriented at + / - 45° along the entire length of the shaft; the final number of 12 biaxial fiber layers to be applied above the mandrel results be equal to the total number of fabrics 11, 12 divided by 5; - the creation 500 of an overlap between said biaxial fabrics 12 and said unidirectional fabrics 11, in order to obtain overlaps 13 which have the aim of making the final shaft rigid and resistant to torsion phenomena which typically involve sailing vessels; the length of overlap being given by the ratio between the mean circumference of the tree and the number of overlaps 13; the number of overlaps 13 being established based on the ratio between the thickness of the tree in millimeters and the thickness of a single layer, divided by 5 and then multiplied by 2; - the vacuum sealing 600 of the fabrics wrapped and arranged 400 above said spindle 10; PRAXI Intellectual Property SpA PF / GZ / 134p2023 - the 700 ignition of an autoclave, in order to obtain a distribution constant of the resin matrix, minimizing the risk of obtaining areas resin-free; - polymerization 800 of the previously impregnated fibres, by means of called autoclave; - the extraction 900 of the mandrel 10, by means of a plurality of coils internally installed refrigerants, designed to facilitate the detachment of the fabrics 11, 12 from said mandrel 10; said mandrel 10 being further capable of reducing its cross-section by using a system extendable / retractable able to expand and decrease its volume, bringing it closer and moving away the external walls of said mandrel 10, thus decreasing the its volume during extraction 900; - the installation of 1000 constraints and hooks for the rigging and halyards; - the 1100 packaging of the tree, inside a casing suitable for keep the tree intact during transport to its destination, that is, in construction site where the said tree will be prepared to be installed on the customer's vessel. It should also be added that fabrics 11, 12 can be pre-impregnated 350 with resin before being positioned 300 on said mandrel 10; alternatively said fabrics 11, 12 can be placed when still dry / dry 370. With reference to FIG. 2, the section of the obtained tree is illustrated. through the above mentioned continuous rolling process, in particular it is the presence of a spindle 10 is made explicit, on which the upper parts are arranged the layers of unidirectional 11 and biaxial 12 fabrics. An overlap between said biaxial fabrics 12 creates overlaps 13, which have the purpose of reinforcing the shaft's hold, while maintaining its constant thickness along its entire section. A tree with a constant thickness will be able to provide superior torsional resistance compared to traditional shafts which PRAXI Intellectual Property SpA PF / GZ / 134p2023 They are made up of two complementary pieces joined together. Finally, it is clear that the invention described up to now can be made subject to modifications, additions or variations that are obvious to a technician in the field, without this go beyond the scope of protection provided by the attached claims.

Claims

PRAXI Intellectual Property SpA PF / GZ / 134p2023 1. Continuous lamination process of sailing ship masts characterized by the fact that it is suitable for the creation of a tree having a constant thickness along its entire section, in order to minimize the bending and twisting undergone during sailing; this process indicating a technique of arranging continuous fibers with a fixed ratio which provides for the arrangement of 80% of unidirectional fabrics (11) at 0°, therefore along the longitudinal axis of the tree and a percentage equal to 20% of tissues biaxial (12) arranged at + / -45°, overlapped to create continuity in the fibres which compose the aforementioned fabrics (11, 12); said fibres being wrapped around to a male mandrel (10), which is used to define the shape and volume interior of the tree produced by means of this process; said process of continuous lamination of sailing vessel masts including the steps Of: - design (100) through FEM analysis based on the type of vessel, whether it is a racing vessel or exclusively used for the cruise sector, examining the loads to which the tree will be subjected during the navigation; - preparation (200) of a mandrel (10), on which the sheets will be rolled layers of fibres used to form the thickness of the final tree obtained; said spindle (10) being equipped with the dimensions of the internal volume of the tree, its dimensions therefore depending on the total length of the tree; - positioning (300) above said spindle (10), of a plurality of fabrics with continuous unidirectional fibres (11) arranged at 0° with respect to the longitudinal axis; said unidirectional fabrics (11) being suitable to constitute the majority of the total thickness of the tree; the number of total fabrics (11, 12) to be used is given by the design thickness PRAXI Intellectual Property SpA PF / GZ / 134p2023 of the tree divided by the thickness of a single layer of tissue (11, 12); - arrangement (400) of biaxial fabrics (12), above said mandrel (10), designed to create a continuity of fibre throughout the tree, using fibres arranged at + / - 45° along the entire length of the shaft; the final number of biaxial fiber layers (12) to be applied above the mandrel being equal to the total number of tissues (11, 12) divided by 5; - creation (500) of an overlap between said biaxial fabrics (12), in order to obtain overlaps (13) capable of making the final shaft rigid and resistant to torsion phenomena that typically involve the sailing vessels; the overlap length being given by ratio between the average circumference of the tree and the number of overlaps (13); the number of overlaps (13) being established on the basis of the ratio between the thickness of the tree in millimeters and the thickness of a single layer, divided by 5 and then multiplied by 2; - vacuum closing (600) of the fabrics wrapped and arranged (400) above said spindle (10); - switching on (700) of an autoclave, in order to obtain a distribution resin constant, limiting the risk of obtaining lamination areas resin-free; - polymerization (800) of previously impregnated fibers, using the said autoclave; - extraction (900) of the mandrel (10), by means of a plurality of coils internally installed refrigerants, designed to facilitate the detachment of the fabrics (11, 12) from said mandrel (10); said mandrel (10) being further able to reduce its section by using a extendable / retractable system designed to expand and decrease its volume, by moving the external walls of said mandrel (10) closer and further apart, then decreasing its volume during extraction (900); PRAXI Intellectual Property SpA PF / GZ / 134p2023 - installation (1000) of the constraints and hooks for the rigging and for the halyards; - packaging (1100) of the obtained tree inside a casing designed to keep the tree intact during transport to its destination, or in the construction site where the said tree will be prepared to be installed on the customer's vessel.

2. Continuous rolling process of sailing ship masts, according to the previous claim 1, characterized in that said fibers unidirectional (11) continuous are made of carbon, to maintain the weights reduced while maintaining the shaft rigid and reliable.

3. Continuous rolling process of sailing boat masts, according to a any of the preceding claims, characterized in that said fabrics (11, 12) are suitable to be pre-impregnated (350) with resin before be positioned (300) on the spindle (10).

4. Continuous rolling process of sailing boat masts, according to a any of the preceding claims 1 to 2, characterized by fact that said fabrics (11, 12) are positioned (300) on the mandrel (10) when they are still dry (370).

5. Continuous rolling process of sailing boat masts, according to a any of the preceding claims, characterized in that said spindle (10) is made of metal, in order to make the drying (800) of the most effective fibers, given the different resistive characteristics of the metal compared to the composite materials used, minimizing the possibility that present deformations in the tree structure.

6. Mast for sailing boats characterised by the fact that it is obtained according to the continuous rolling process previously described, obtaining a torsional resistance superior to all the trees that the current one state of the art are made by two portions glued together; the PRAXI Intellectual Property SpA PF / GZ / 134p2023 This tree being made of a single piece, having a thickness constant along its entire section, allowing the creation of a tapering that makes the head of the said mast lighter and more aerodynamic, in order to reduce the heeling moment of the vessel on which said tree is installed.