Method for manufacturing a bicycle frame made of wood composite material and bicycle frame made of wood composite material

Abstract

A method for manufacturing a bicycle frame (1) from wood composite material, comprising a preliminary step of manufacturing several plies of wood composite material and other plies that may be made of wood alone and / or of mineral and / or vegetable fiber alone, each ply being flat and corresponding to the developed shape of the frame (1), and a molding step of two stacks of several plies each, placed side by side, and of inserts (30, 31, 32, 33) positioned between the two stacks, the molding consisting simultaneously of assembling the plies and stacks by polymerizing a bonding resin and shaping them three-dimensionally around and securely around the inserts. The bicycle frame thus obtained is completely monolithic and ready for the mounting of bicycle accessories.

Description

Title of the invention: Method for manufacturing a bicycle frame made of wood composite material and bicycle frame made of wood composite material

[0001] The invention relates to the manufacture of a bicycle or bike frame made of wood composite material.

[0002] In recent years, a new product has appeared on the bicycle market: bicycles with wooden frames. Wood is aesthetically pleasing and offers good shock absorption properties.

[0003] A distinction is made between bicycle frames made of raw wood and those made of wood composite material. In the following description, "wood composite" means a material made up of layers of wood and plastic and / or fibrous materials such as carbon fibers or plant fibers.

[0004] Raw wood frames have the disadvantage of being heavy and too rigid, which does not provide effective responsiveness when riding a bicycle. Furthermore, a bicycle frame has a complex shape and comprises several parts: a top tube, a down tube, a seat tube, a head tube, two seat stays, and two chain stays. The frame must therefore be made in several pieces by working with raw wood, which is time-consuming. The pieces are then assembled by gluing and / or using mechanical fasteners such as screws. This mechanical assembly can make the frame noticeably unsightly, and the use of screws made of materials other than wood can, over time, degrade the structure.

[0005] As for wood composite frames, they have the advantage of being lighter and exhibiting better responsiveness. A method for manufacturing a wood composite bicycle frame is known from patent EP3517419B1; the method consists of taking a plate or a solid blank of composite material of a thickness appropriate to the final thickness of the frame, the blank being made up of bonded layers of wood, plastic foam and carbon fibers, then cutting the blank by contouring it to the desired geometry to correspond to the shape of the frame, making grooves along the edge of the frame geometry, into which glue is injected to delimit the cutting perimeter of the blank and seal the edge of the cut composite material, and finally removing the cut sections of the blank, which are unnecessary, from inside and outside the frame.However, this process only allows for the manufacture of a portion of the frame, namely the main coplanar part, generally asymmetrical trapezoidal in shape, comprising the top tube, down tube, seat tube, and head tube. In contrast, the two seat stays and the rear stays extend in two distinct planes. Components different from the tube design must be designed independently and then mechanically attached to the seat tube. This involves additional operations and requires additional mechanical fasteners, such as screws, to secure the seat stays and chain stays to the main frame. Furthermore, as mentioned previously, mechanical assemblies can make the entire bicycle frame aesthetically unappealing, and the use of screws can, over time, lead to disassembly and degradation of the composite material. Moreover, the process described in the aforementioned patent generates a significant amount of waste compared to the remaining blank sections after the main frame section has been cut.

[0006] Furthermore, the bicycle frame must be designed to accommodate and attach the bicycle's accessory parts (seat tube, steering pivot, bottom bracket, etc.). This requires machining the frame or designing specific parts to attach to the frame, which adds further operations during manufacturing and can create weaknesses in the frame sections where the accessories are housed and attached.

[0007] The invention therefore aims to propose a method for manufacturing a bicycle frame made of wood composite for its property of relative lightness, which does not present the aforementioned disadvantages, in particular which makes it possible to reduce the number of operations in the manufacture, to avoid the mechanical assembly of several parts, incidentally to optimize the quantity of useful material as much as possible, while providing a frame that is responsive in the practice of cycling, comfortable with regard to the absorption of shock waves and aesthetic.

[0008] According to the invention, the method for manufacturing a bicycle frame from wood composite material comprises a preliminary step of manufacturing several (independent) plies, at least one of which is made of wood composite material and other plies which may be made of wood alone and / or of mineral and / or vegetable fibrous material alone, each ply being flat in shape and corresponding to the developed shape of the final bicycle frame to be obtained, and a step of molding two stacks of several plies each, which have been placed side by side by having positioned inserts between the two stacks (in localized places), the molding consisting simultaneously of assembling the plies and stacks by polymerizing a bonding resin and shaping them three-dimensionally around and in a way that is integral to the inserts so as to provide a monobloc frame with the desired shape (with the desired curves) and which overmolds the inserts.The term "overmolding" inserts refers to the process of making them integral to the frame's constituent material by embedding them within it (without the use of external fixing methods), with parts of the insert potentially protruding from the frame.

[0009] According to one characteristic, a ply is single-layered or multi-layered and comprises one material or several materials. A ply made of a single material is hereafter called a monolithic ply (the ply being single-layered or multi-layered). A ply made of A composite ply made of several different materials is called a composite ply, this ply being multi-layered. By definition, a ply is a rigid or semi-rigid piece that is manageable on its own, but flexible enough to deform and conform to the shape of the mold through compression.

[0010] According to one feature, the manufacturing process comprises the prior fabrication of several flat plies, each having the developed shape of the bicycle frame to be obtained. In particular, each plie is a single-piece (single-layer or multi-layer) comprising a so-called main part made up of elements that define the developed shape of the top tube, down tube, seat tube, and head tube, and a so-called rear part made up of elements that define the developed shape of a seat stay and a rear stay. According to one feature, the manufacturing process further comprises the following steps - use of a mold adapted to receive the folds in a stacked manner, and the inserts constituting parts of bicycle accessories, as well as to provide the final shape of the bicycle frame (the mold therefore including ad hoc housings for receiving the folds and inserts, the three-dimensional shape of these housings allowing after molding to obtain the three-dimensional shape of the frame); - opening of the mold; - in a part of the mold, stacking of several layers and between each layer, depositing of a bonding material, to constitute a first stack; - arrangement of the inserts by depositing them in a localized manner on the first stack of plies, and holding them temporarily fixed to the mold via tooling integrated into the mold; - in another part of the mold and opposite the first stack, stacking of several other layers with a deposit of a bonding material between each layer, to constitute a second stack; - installation of an intermediate mold part which forms a spacer between the two stacks and only opposite the rear part of the stacks (the rear part corresponding to the shrouds and the rear bases); - closing the mold and applying compression to constrain and glue the two stacks together by sandwiching the inserts and conforming to the shape of the mold, possibly a concomitant heating step during the compression of the mold; - opening of the mold and demolding of the bicycle frame, which is a single-piece wood composite assembly, including the top tube, down tube, seat tube, head tube, two spaced seat stays and two spaced rear chain stays, as well as the insert parts overmolded with the wood composite material, in particular the insert parts being a seat tube insert, a bottom bracket insert, a head tube insert and a rear fitting insert.

[0011] Thus, the manufacturing process provides a wood composite bicycle frame that is completely monolithic (one-piece) by integrating the inserts for bicycle accessories. The bicycle frame is complete and even includes, in a single piece, both seat stays and both chain stays, without any added mechanical assembly means. The two seat stays and the two chain stays extend in planes parallel and distinct from the plane of the main part of the frame, while exhibiting the appropriate curvatures. Furthermore, the operations for obtaining this monolithic frame are optimized, comprising only the preliminary production of a plurality of flat plies of wood composite and the molding operation.

[0012] Naturally, wood composite plies, by virtue of their appropriate thickness (and the nature of the wood), possess a flexibility that allows them to be shaped by compression. The thickness of a ply is, in particular, less than 10 mm, specifically between 0.6 mm and 6 mm. The plies in a stack can be of different thicknesses. A wood composite ply is a piece of wood covered with a fibrous material in one or more layers, the weave and basis weight of which can vary from one layer to another. The fibers can be unidirectional or multidirectional, particularly bidirectional. The fibrous material can be oriented differently from one layer to another and / or located differently on the ply.Depending on the positioning of the plies in the stack, the fibrous material per plie can differ in its nature and / or its weight and / or its weave and / or its orientation relative to the wood grain or relative to its location on the plie, particularly depending on the areas of the future frame.

[0013] According to one feature, the manufacturing step of the plies includes a cutting step to contour and create, in a localized manner within the thickness of the plies, through holes and / or blind cavities. This serves to lighten the bicycle frame, allows the inserts to be embedded once the plies are stacked, and subsequently provides, after molding, channels for the passage of cables inside the frame. Not all plies are necessarily identical in the contouring and / or arrangement of the holes and / or blind cavities.

[0014] According to one feature, the plies are made of wood composite material and mineral and / or vegetable fibrous material, each wood composite ply being a piece of wood covered with a fibrous material and a polymerized resin and each mineral and / or vegetable fibrous material ply being a piece of fibrous material with a polymerized resin.

[0015] According to one feature, the manufacturing of a fold (according to a part extending in a plane) comprises the following steps (in a preferred embodiment): - join together, preferably in a template, a plurality of (long) wooden slats to draw the rough shape of a frame (the set of slats presents surfaces which are circumscribed to the developed surface of each of the frame elements which are the top tube, the diagonal tube, the seat tube, the head tube, a seat stay and a rear stay), - For a wood composite ply, cover all the slats with at least one fibrous material (one or more layers of one or more fibrous materials) and a polymerizing resin (the slats will bond at their joint edges during resin polymerization). After polymerization, this creates a wood composite piece, which is then cut to provide the ply for stacking (the ply thus having the unfolded shape of the frame and including, if necessary, blind holes and / or cavities). Therefore, only wooden slats are used, and the fibrous material and resin are limited to the surface of the slats. The flat, single-piece, roughly shaped piece of wood composite simply needs to be cut to give it the exact profile corresponding to the unfolded surface of the frame, thus forming a ply.The amount of manufacturing material is advantageously optimized, and material waste from cutting is minimized. For the manufacture of a ply in fibrous material only, the material is deposited in a mold and polymerization resin is added to form, after polymerization, a single piece of fibrous material.

[0016] According to one feature, several folds are made at the same time and in that during polymerization, several pieces of wood covered with fibrous material and polymerization resin and / or one or more templates in which fibrous material and polymerization resin have been deposited, are arranged next to each other on a flat surface (in particular the surface being non-stick) and covered with a sealed envelope in which a vacuum is created.

[0017] According to one characteristic, each wooden slat has its longitudinal direction extending along the grain of the wood.

[0018] According to one characteristic, the thickness of the wooden slats is between 0.5 and 5 mm and the thickness of the fibrous material is between 0.1 and 1 mm.

[0019] According to a characteristic, the wood is chosen from ash and / or poplar and / or paulownia.

[0020] According to one characteristic, the fibrous material is chosen from carbon fibers and / or glass fibers and / or plant fibers, preferably flax fibers.

[0021] According to one feature, during the compression of the mold, the process includes a concomitant heating step.

[0022] According to one feature, the process includes, after demolding, sanding and spraying steps of protective layers of the type against water, shocks, against UV.

[0023] The invention also relates to a mold for implementing the aforementioned manufacturing process of the invention, the mold comprising five parts: - a first part having a female shape which corresponds to the shape of a lateral face of the main part of the frame to be obtained and housings adapted to partially accommodate bicycle accessories and to hold them temporarily fixed by tools integrated into the mold, - a second part designed to cooperate with the first part in the closed position and comprising a female shape which corresponds to the shape of the other lateral face of the main part of the frame and housings to fit the shape of the accessories in the closed position of the mold, - a spacer part which is removable and intended to be butted in line with the first and second parts of the mold when these are in their closed position, while also being intended to be positioned between the rear parts of the stacks and comprising on two opposite faces female shapes which are each intended to receive each of the rear parts of the two respective stacks, - two so-called rear closing parts intended to cooperate with the two opposite faces of the spacer part in the closed position.

[0024] The invention also relates to a one-piece wood composite bicycle frame, comprising both a main frame section, which is coplanar and includes a top tube, a down tube, a seat tube, and a head tube, and a rear frame section, which includes, in two parallel and opposing planes distinct from the plane of the main frame section, two pairs of seat stays and chain stays, and inserts overmolded into the wood composite material. The entire frame is a single piece, free from added mechanical assembly means such as mortise and tenon joints, nails, or screws.

[0025] The present invention is now described by means of a purely illustrative and in no way limiting example of the scope of the invention, and from the accompanying illustrations, in which: - [Fig.1] represents a perspective view of an example of a frame obtained according to the manufacturing process of the invention. - [Fig.2] illustrates a schematic perspective view of the mold for implementing the manufacturing process, opened with its different parts. - [Fig.3] is a top view of the first part of the mold in the open position of the mold. - [Fig.4] illustrates an example of a wood composite ply that is intended to be part of a stack of plies in a bicycle frame. - [Fig.5] shows the closed mold with one of the rear closing parts open and disassembled, revealing after molding one of the pairs of seat stays and rear stays of the bicycle frame. - [Fig.6a] is a top view of the first stage of manufacturing a wood composite ply, this first stage being the flattening of wooden slats to form a piece of wood with a general diamond shape with a diagonal. - [[Fig.6b]] corresponds to the step that follows that of [Fig.6a] by depositing a fibrous coating on the piece of wood and a polymerization resin. - [[Fig.6c]] shows the vacuum and polymerization step of the different parts conforming to that of [Fig.6b]. - [[Fig.6d]] illustrates a wood composite part from the manufacturing step of [Fig.6c] which has been cut to trace in an inscribed manner the wood composite ply of [Fig.4].

[0026] The bicycle frame 1 of the invention illustrated in [Fig. 1] was manufactured according to the manufacturing process of the invention explained below. The frame 1 of the invention has the particularity of being a single piece by comprising, in a single unit and without added means of fixing, on the one hand, all the parts of a frame, namely the top tube 20, the diagonal tube 21, the seat tube 22, the head tube 23, the two seat stays 24A and 24B and the two rear stays 25A and 25B, and on the other hand, inserts of bicycle accessory parts, here inserts 30, 31, 32 and 33, preferably metallic.

[0027] Thus, the frame 1 of the invention advantageously provides in one piece, both the main part 10 of the frame which is in a single plane and includes the top tube 20, the diagonal tube 21, the seat tube 22, the head tube 23, and the rear part 11 of the frame which includes in two parallel and opposite planes distinct from the plane of the main part 10, the two respective pairs 11A and 11B of the seat stay 24A and the rear stay 25A, and respectively of the seat stay 24B and the rear stay 25B.

[0028] Furthermore, the frame 1 resulting from the manufacturing process of the invention allows for the direct integration of inserts 30 to 33 for the subsequent attachment of bicycle accessories such as the bottom bracket, saddle, steerer tube, and rear fittings. The metal insert 30 of the bottom bracket extends along the thickness of the frame and is located, and fixed to it, at the junction of the rear stays 25A, 25B, the seat tube 22, and the down tube 21. The metal insert 31 of the saddle is positioned and fixed to the upper distal end of the seat tube 22. The metal insert 32 of the steerer tube is positioned and fixed to the upper distal end of the head tube 23. The metal insert 33 rear fittings are arranged at the free end of the rear base, at the end and between the shrouds and the rear bases.

[0029] The manufacturing process for the frame 1 comprises a preliminary step of producing several plies IA, IB, etc., of wood composite material and preferably of fibrous material alone (and possibly of plastic material alone), of planar shape and whose geometry corresponds to a lateral and elevational view of the frame 1, and a molding step of two stacks 100 of several plies IA, IB, etc., and inserts 30 to 33, the molding consisting of assembling the plies and stacks by polymerizing a bonding resin and shaping them three-dimensionally around and securely around the inserts. Only the first stack 100 is visible in [Fig. 3].

[0030] The manufacturing process for the frame 1 is implemented using a shaping mold 4 illustrated in [Fig. 2]. The mold 4 comprises several parts, in particular five parts. The mold 4 comprises a first part 40 (also visible in [Fig. 3]) and a second part 41 opposite the first part, the two parts 40 and 41 being designed so that, in the closed position of the mold, they assemble and shape the main part 10 of the frame 1 by assembling and shaping the two stacks 100 of several plies of wood composite and optionally plies of wood alone and / or plies of fibrous material alone, while overmolding a part of the inserts 30 to 33 which were placed before closing the mold against the first stack 100 and opposite the second stack.Furthermore, the mold 4 comprises three other parts 42, 43 and 44 which assemble and shape the rear part 11 of the frame comprising the two opposing pairs 1 IA and 1 IB of a stay and a rear base. The three said other parts 42, 43 and 44 comprise: . - a so-called spacer part 42 which is removable and is positioned between the two stacks 100 and opposite the wood composite elements corresponding, after molding, to the stays 24A, 24B and the aft bases 25A, 25B; and - the so-called rear closing parts of the mold 43 and 44 which are removable and able to cooperate with respectively the opposite faces 42A and 42B of the spacer part 42.

[0031] The various parts of the mold and the environment of the mold include, in a known manner, tooling not shown to support the mold, close the various parts, tighten them and compress them.

[0032] More specifically, the manufacturing process comprises the following steps: - production of several plies IA, IB, IC, etc. in wood composite and planes and optionally one or more plies in fibrous material alone, each ply forming a single piece, as illustrated in [Fig. 4], having the developed shape of the bicycle frame to be obtained and comprising in one piece elements 10A, 10B, 10C and 10D which respectively draw the developed surface of the top tube, the diagonal tube, the seat tube and the head tube, and of the elements 10E and 10F which respectively draw the developed surfaces of a seat stay and a rear stay; - use of the mold 4 to receive the folds in a stacked manner, and the inserts 30 to 33 constituting parts of bicycle accessories, as well as to provide the final shape of the bicycle frame; - opening of mold 4; - in the first part 40 of the mold ([Fig.3]), several plies IA, IB and IC are stacked with a bonding material deposited between each ply, to constitute the first stack 100. The first part 40 of the mold is limited in surface area so as to accommodate the elements 10A to 10D of the stack 100 while the elements 10E and 10F of the stack are outside this first part 40 of the mold and open into the void. The stacking of the plies in the first part 40 takes place while the mold is in a horizontal plane; - arrangement of inserts 30, 31, 32 and 33 by depositing them in a localized manner on the first stack 100 of plies, and keeping them temporarily fixed to the mold via tools 45 integrated into the mold; - stacking on inserts 30, 31, 32 and 33 and on the first stack 100 of several other plies IA, IB and IC with deposition between each ply of a bonding material, to constitute the second stack; - application of the second part 41 of the mold onto the second stack. The second part 41 of the mold is also limited in surface area so as to accommodate the elements 10A to 10D of the second stack while the elements 10E and 10F of the stack are outside this second part 41 of the mold and open into the void; - closing the first and second parts 40 and 41 of the mold against each other and straightening these two closed parts of the mold vertically. The two elements 10E and 10F of the first stack 100 on the one hand, and the two elements 10E and 10F of the second stack on the other hand, are in the void and are spaced apart and opposite each other; - placement of the spacer part 42 of the mold by inserting it between the two elements 10E and 10F of the first stack 100 and the two elements 10E and 10F of the second stack and fixing of this spacer part 42 (by removable fixing means 42' as illustrated in [Fig.5]) to the first part 40 and to the second part 41 of the mold (at the level of the edge of the first and second parts 40 and 41), ; - The rear closing parts 43 and 44 are placed against the respective faces 42A and 42B of the spacer part 42, and the mold is closed, then the mold 4 is compressed. The compression forces and bonds the two stacks together. against the other by sandwiching inserts 30 to 33 and conforming to the shape of the mold to give frame 1 its final shape; - opening of the mold 4, dismantling of the spacer part 42 of the mold, dismantling of the fixings of the inserts 30 to 33 in relation to the tools 45 and demolding of the frame 1 which then constitutes the monobloc assembly of the [Fig.l].

[0033] The adhesive material for assembling the folds and stacks is a resin that advantageously polymerizes after a certain application time. The mold 4 has, for each of the mold parts 40, 41, 43, and 44, a respective female form 40', 41', 43', and 44', and for the spacer part 42, a female form 42" on each of the faces 42A and 42B. Each female form 40', 41', 42", 43', and 44' is adapted to the desired three-dimensional shape of the frame and to the volume and shape of the inserts 30 to 33. Each female form 40' to 44' has a clearance with the mold wall allowing for the application of adhesive to ensure perfect assembly of all the folds and stacks.

[0034] When opening the mold 4, the rear closing parts 43 and 44 are first opened and disassembled in order to free the stays and the rear bases ([Fig. 5]). Then the spacer part 42 is disassembled and finally the first and second parts 40 and 41 of the mold are opened.

[0035] The frame 1 is composed of a plurality of plies, three (preferably the first) plies IA, IB, and IC being visible in the stacking 100 of [Fig. 3]. [Fig. 4] illustrates an example of the wood composite ply IC, the innermost one in the frame. While each of the plies in the stackings constituting the frame 1 has an identical contour to correspond to the general geometry of the frame 1, the plies may, however, have differences in their surface cross-section. Each of the plies has, in its surface, localized and not systematically in the same place, through holes 50 of different geometries and possibly blind cavities 51. The through holes 50 and the blind cavities 51 serve, depending on their location, to provide housings for inserts, to create lightened and localized areas in the final frame 1, or to provide additional thickness. Compared to the three plies IA, IB, and IC visible in [Fig. 3], the frame 1 is composed of three plies (preferably the first) IA, IB, and IC.[4] We can see that the plies IA and IB have solid surfaces at the junction of the end of the stay 24A and the rear base 25A, while the inner ply IC, which will be inside the frame, is hollow at this junction between elements 10E and 10F. Here, as a non-limiting example, the three plies IA, IB and IC are made of wood composite but with a different fibrous material structure.

[0036] The operation of creating a wood composite fold can be carried out in the following manner: 1) flattening of at least one piece of wood 60 ([[Fig.6a]]), the piece of wood reproducing a general diamond shape with a diagonal; preferably, Several pieces of wood 60 are placed next to each other, preferably using a template, and simultaneously undergo the following processing steps; 2) covering ([[Fig.6b]]) of said at least one piece of wood 60 with a fibrous material 61 and impregnation with a fixing resin; 3) covering said at least one piece of wood 60 and of the fibrous material 61 by a sealed envelope 7 and placing under vacuum (by suction means 70) the sealed envelope 7 ([[Fig.6c]]) during a polymerization step of the resin to constitute after polymerization a composite piece of wood 62; 4) removal of the waterproof envelope 7; 5) Trimming and cutting the wood composite part 62 ([[Fig.6d]]) to draw and form the wood composite ply IC of [Fig.4] corresponding to the developed shape of the frame, including the elements mentioned above, 10A, 10B, 10C, 10D, 10E and 10F, and providing the ply 1A with through holes 50 and blind cavities 51. Machining (trimming and cutting) the wood composite part 62 can be done by laser cutting, water jet cutting, or other cutting process, and preferably by numerical control.

[0037] Regarding step 1) of flattening the piece of wood 60, the piece of wood 60 is preferably obtained by laying flat and joining end-to-end ([Fig. 6a]) a plurality (five) of wooden slats 60A to 60E to form a diamond shape with a diagonal, each wooden slat advantageously having its longitudinal direction extending along the grain of the wood. This design for the piece of wood 60, using slats whose longitudinal direction corresponds to the grain of the wood, ultimately results in a frame 1 that is both robust and responsive (in its use). The set of wooden slats assembled 60A to 60E corresponds to surfaces which are circumscribed to each of the elements 10A, 10B, 10C, 10D, 10E and 10F which respectively draw the developed surface of the top tube, the diagonal tube, the seat tube, the head tube, a stay and a rear stay.

[0038] The wooden slats 60A to 60E are preferably held together by means of a template. The template is advantageously slightly thinner than the slats and is made of a self-releasing or non-stick material (at least for its surface in contact with the slats).

[0039] The wooden slats 60A to 60E which are joined together to form the wooden piece 60 are preferably of the same thickness. The thickness of a wooden slat is between 0.5 and 5 mm and is, for example, 3 mm.

[0040] The wood parts 60 can have different thicknesses. Wood parts 60 that do not require shaping but are machined from a solid block can be up to 50mm thick.

[0041] The preferred wood species are ash, poplar and paulownia.

[0042] Step 3) of depositing the fibrous material 61 and a polymerization resin makes it possible to join the wood slats 60A to 60D butted together.

[0043] The fibrous material 61 consists of a fabric with a weave that is, for example, unidirectional, taffeta, or bi-bias. The fibrous material 61 preferably has a thickness between 0.1 and 1 mm. The fibrous material may be carbon fiber and / or glass fiber and / or plant fiber such as flax fiber.

[0044] The fixing resin is preferably a bio-based epoxy resin. Other resins may be used, such as polyester-based, polyurethane, or silicone adhesives.

[0045] The fixing resin is preferably applied to the fibrous material once it has been placed on the wooden slats. Alternatively, the fibrous material could already be pre-impregnated with resin.

[0046] The fibrous material 61 covers all or part of each of the wooden slats of a piece of wood 60. The fibrous material 61 covers the one or both opposite faces of a piece of wood 60.

[0047] Regarding steps 2) and 3), it is preferably made several pieces of wood 60 which are laid flat on a single surface, then covered each with fibrous material 61, a single airtight envelope 7 covering the whole plurality of wood pieces 60 covered with fibrous material 61, by the envelope 7 in order to manufacture in a single step of polymerization and vacuum packing a plurality of composite wood pieces 62. This saves manufacturing time.

[0048] As an alternative to step 1) (arranging slats in a diamond pattern with a diagonal) and step 5) (cutting all the lines of the frame elements 10A to 10F), the process could include a direct step of cutting each of the elements 10A to 10F of a wood composite ply to its final shape. The individually cut elements 10A to 10F would then be butted together to form the shape of the ply and thus the frame, and then the fibrous material would be deposited with the resin; after polymerization, the wood composite ply IA would be obtained directly.

[0049] Once the frame 1 has been removed from the mold, the manufacturing process includes finishing steps: sanding and spraying of protective coatings such as water, impact, and UV protection, as well as aesthetic finishing. The bicycle accessories are then ready to be mounted.

Claims

Demands

1. A method for manufacturing a bicycle frame (1) made of wood composite material comprising a preliminary step of manufacturing several plies (IA, IB, IC) of which at least one ply is made of wood composite material and other plies which may be made of wood alone and / or of mineral and / or vegetable fibrous material alone, each ply being planar in shape and corresponding to the developed shape of the frame (1) and comprising in one piece elements which form the developed surface of a top tube, a down tube, a seat tube, a head tube, a seat stay and a rear stay, and a step of molding two stacks (100) of several plies (IA, IB, IC) each, which have been placed opposite each other by having positioned between the two stacks inserts (30, 31, 32, 33),The molding process consists of simultaneously assembling the folds and stacks by polymerizing a bonding resin and shaping them three-dimensionally around and securely attaching them to the inserts.

2. A manufacturing method according to claim 1, characterized in that each previously manufactured ply (IA, IB, IC) is a single piece comprising a main part (10) made up of elements that form the developed shape of the top tube (20), the down tube (21), the seat tube (22) and the head tube (23), and a rear part (11) made up of elements that form the developed shape of a seat stay (24A; 24B) and a rear stay (25A; 25B), and the method comprises the following steps: - use of a mold (4) adapted to receive the folds (IA, IB, IC) in a stacked manner, and the inserts (30, 31, 32, 33) constituting parts of accessories of the bicycle, as well as to provide the final shape of the frame (1); - opening of the mold (4); - in a part (40; 40') of the mold, stacking of several layers and between each layer, deposit of a bonding material, to constitute the first stack (100); - arrangement of the inserts (30, 31, 32, 33) by depositing them in a localized manner on the first stack (100) of folds, and keeping them temporarily fixed to the mold via tools (45) integrated into the mold; - in another part (41; 41') of the mold and opposite the first stack (100), stacking of several other plies (IA, IB, IC) with a deposit of a bonding material between each ply, to constitute a second stack; - placement of an intermediate part (42) of the mold which forms a spacer between the two stacks (100) and only opposite the rear part (11) of the stacks; - closing of the mold (4) and compression to constrain and bond the two stacks (100) against each other by sandwiching the inserts (30, 31, 32, 33) and conforming to the shape of the mold, possibly a concomitant heating step during the compression of the mold;- opening of the mold (4) and demolding of the frame (1) which constitutes a single piece of wood composite, comprising the top tube (20), the diagonal tube (21), the seat tube (22), the head tube (23), the two spaced seat stays (24A, 24B) and the two spaced rear stays (25A, 25B), as well as the insert pieces (30, 31, 32, 33) overmolded by the wood composite material, in particular the insert pieces being a seat tube insert (30), a bottom bracket insert (31), a head tube insert (32) and a rear fitting insert (33).;

3. Manufacturing method according to claim 1 or 2, characterized in that the folding manufacturing step includes a cutting step to contour and locally create in the thickness of the folds through holes (50) and / or blind cavities (51).

4. A method according to any one of the preceding claims, characterized in that the plies are made of wood composite material and mineral and / or vegetable fibrous material, each wood composite ply being a piece of wood covered with a fibrous material and a polymerized resin and each mineral and / or vegetable fibrous material ply being a piece of fibrous material with a polymerized resin.

5. A method according to any one of the preceding claims, characterized in that the manufacture of a fold comprises the following steps: - joining together, preferably in a template, a plurality of wooden slats (60A, 60B, 60C, 60D) to draw the rough shape of a frame, - for a wood composite ply, cover all the slats with at least one fibrous material (61) and a polymerizing resin, to provide after polymerization a wood composite piece (62), and cut the wood composite piece (62) to provide the ply intended for stacking.

6. A method according to the preceding claim, characterized in that several layers are manufactured at the same time and in that during polymerization, several pieces of wood covered with fibrous material and polymerization resin and / or one or more templates in which fibrous material and polymerization resin have been deposited, are arranged next to each other on a flat surface and covered with a sealed envelope in which a vacuum is created.

7. A method according to claim 5 or 6, characterized in that each wooden slat has its longitudinal direction extending along the grain of the wood.

8. A method according to any one of the preceding claims, characterized in that the thickness of the wooden slats (60) is between 0.5 and 5 mm and the thickness of the fibrous material (61) is between 0.1 and 1 mm.

9. A method according to any one of the preceding claims, characterized in that the wood is selected from ash and / or poplar and / or paulownia and the fibrous material is selected from carbon fibers and / or glass fibers and / or vegetable fibers, preferably flax fibers.

10. A method according to any one of the preceding claims, characterized in that it comprises, after demolding, sanding and spraying steps of protective layers of the type against water, shocks, against UV.

11. Mold (4) for implementing the manufacturing process according to any one of the preceding claims, the mold comprising five parts: - a first part (40) having a female shape (40') which corresponds to the shape of a lateral face of the main part (10) of the frame to be obtained and housings adapted to partially accommodate bicycle accessories and to hold them temporarily fixed by tools (45) integrated into the mold, - a second part (41) intended to cooperate with the first part (40) in the closed position and comprising a female form (41') which corresponds to the shape of the other lateral face of the main part (10) of the frame and housings to fit the shape of the accessories in the closed position of the mold, - a spacer part (42) which is removable and is intended to be butted in the extension of the first and second parts (40, 41) of the mold when these are in their closed position, while being intended to be positioned between the rear parts (11) of the stacks (100) and comprising on two opposite faces (42A, 42B) female forms which are each intended to receive each of the rear parts (11) of the two respective stacks (100), - two so-called rear closing parts (43, 44) intended to cooperate with the two opposite faces (42A, 42B) of the spacer part (42) in the closed position.

12. One-piece wood composite bicycle frame (1), comprising both a main part (10) of the frame which is coplanar and includes a top tube (20), a down tube (21), a seat tube (22), a head tube (23), and a rear part (11) of the frame which includes, in two parallel and opposite planes and distinct from the plane of the main part, two pairs of seat stays (24A, 24B) and rear stays (25A, 25B), and inserts (30, 31, 32, 33) overmolded in the wood composite material.

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