Bicycle frame incorporating a braking device

BIKE FRAME INCLUDING A BRAKING DEVICE

0002The present invention relates to a bicycle frame incorporating a braking device for a rim wheel, more particularly for a bicycle rim wheel. bans in the field of cycling, bikes generally include two wheels mounted on a frame and drive means with a crankset comprising at least one chainring, at least one drive pinion secured to the rear wheel and a transmission chain between the chainring and the pinion, for the vast majority.

0003Nevertheless, significant progress has been made in the area of ​​cycling, notably under the impact of major international events and the professionals who participate in them.

0004In this sporting field, amateurs are also very demanding and are looking for high performance equipment.

0005This is how frames have greatly evolved and we know that this is a very important part in the behavior of a bicycle.

0006In fact, the quality of a framework largely depends on the yield and the return of efforts.

0007We must solve a problem that must link two contradictory parameters:

0008- the stiffness to avoid deformations and therefore the absorption of energy, and - the weight which must be reduced in order not to penalize the practitioner, in particular during the presence on the course of slopes, or even strong slopes. This is how the applicant of the present invention has been led to resort to composite materials integrating carbon fibers and / or other technical fibers for the production of the frames.

0009The components mounted on these frames are very sophisticated both from the point of view of the mechanisms and of the materials that constitute them.

0010This is how the stems, handlebars, derailleurs and their controls have evolved a lot.

0011On the other hand, there has been relatively little progress in the field of brakes, which are safety elements first but also performance. Practitioners especially in competition but also experienced amateurs need braking devices with excellent performance in downhill especially when the weather conditions are bad.

0012Progress has been made on the braking interface. Thus, the annular zone of the rim undergoes surface treatments such as ceramization and the brake pads themselves are made of materials capable of braking even in the presence of water, in a progressive manner, and these pads are susceptible to maintain these performances even when a high temperature rise occurs.

0013The mechanism for exerting pressure of these pads on the rim remains practically unchanged. This mechanism includes:

0014- a lever-type actuator, maneuverable by the practitioner, and

0015- a transmission of the actions printed by the practitioner on the lever to the braking means by cable or by any other means including by hydraulic fluid. These known braking means use a pair of arms arranged on either side of the rim. Each arm is rotatably mounted on a pivot which is integral with the frame. Two arrangements are then possible: - either one end of the arm carries the shoe, the other end is linked to the transmission and the pivot is interposed between the two ends,

0016- either one end of the arm is mounted on a pivot, the other end is linked to the transmission and the shoe is interposed between the two ends,

0017The directions of traction exerted by the transmission are adapted so that each shoe is pressed against the rim when the user exerts a force on the lever with a multiplier effect.

0018Each of the arms further comprises return means, for example in the form of a loop spring, generally interposed between the frame and the arm so as to return the arm and the pad which it carries after the rim back. practitioner exercised an action.

0019These arrangements of the prior art have the drawback of requiring a pivot connection of which several drawbacks can be mentioned. The friction of the arm on the pivot is high, especially since there are particles projected during rolling which may have been introduced between the pivot and the arm. This generates rapid wear of the pivot link and greater efforts to activate the braking.

0020In addition, there is the presence of a spring, which is an additional part, an additional weight, a source of problem by its very presence. As this spring has a return function, the user must exert a first effort to cancel this return effort to which is added a second effort to brake. To be sure of an effective return of the arm carrying the shoe and to overcome any additional friction at the right of the pivot link generated by the mud, the return means, generally a spring, are oversized.

0021The effort exerted by the practitioner to cancel this effort during braking is therefore increased accordingly. It should be noted that, on a bicycle, the practitioner must maintain the handlebars and act with one or more fingers on the lever so that it would be attractive for the practitioner to have to exert only a small effort, corresponding in in addition to almost only the braking effort. The braking precision would only be better. It is recalled that there is no possibility of introducing brake assist as in motorized vehicles.

0022As for the solution which would consist in increasing the length of the arms, it must be tempered by the fact that the necessary stroke at the level of the lever increases. Also, rather than increasing the power, it is necessary to remove parasitic friction.

0023Another drawback of the pivot link also lies in the possible progressivity defects during braking actions, especially if partial seizures of said pivot link occur due to irregular wear of the surfaces in contact due to repeated friction. We also note that it is difficult to integrate the arms of the braking devices of the prior art in a frame all the more so when it is a high-end frame made of composite material, the aerodynamics, the solidity and / or simply the aesthetics of the frame being disturbed or even compromised. The present invention provides a bicycle frame incorporating a braking device which is progressive, which eliminates the risks of seizure, which is lighter and more reliable than the devices of the prior art by removing a part and the pivot link. , but also by the possibility of making the frame and the braking device of composite material. The integration of a braking device into a bicycle frame according to the invention offers possibilities of aerodynamic profile and particularly aesthetic forms with total integration of said device in the branches of the front and / or rear forks of said frame. To this end the invention α relates to a bicycle frame comprising at least one fork comprising two branches mounted on either side of a rim wheel, said frame being equipped with a braking device such that each branch of said fork incorporates at least one braking element comprising means for securing to the frame, a rigid arm movable relative to said securing means and capable of taking all the positions between two extreme positions of rest and braking, a friction member carried by this arm and designed to cooperate with said wheel rim, as well as a connection elastic return interposed between the securing means and the arm. The bicycle frame according to the present invention is now described in detail according to several embodiments.

0024This description is based on the appended drawings including various figures which represent:

0025- Figure 1: a schematic isolated perspective view of a fork of a bicycle frame according to the invention in a first embodiment of the means for securing a braking element E comprising an elastic connection according to a first embodiment production,

0026- Figures 2A and 2B: a schematic sectional view along a transverse median plane of a fork of a bicycle frame according to the invention in a first embodiment of the means for securing a braking element E comprising a connection elastic according to a first embodiment, in the rest and braking position of said element E,

0027FIG. 3: a schematic isolated perspective view of a braking element comprising an elastic connection according to a second embodiment,

0028- Figures 4A and 4B: a schematic sectional view along a transverse median plane of a fork of a bicycle frame according to the invention in a second embodiment of the means for securing a braking element E comprising a connection elastic according to a second embodiment, in the rest and braking position of said element E,

0029FIG. 5: a schematic isolated perspective view of a braking element comprising an elastic connection according to a third embodiment,

0030- Figures 6A and 6B: a schematic sectional view along a transverse median plane of a fork of a bicycle frame according to the invention in a third embodiment of the means for securing a braking element E comprising a connection elastic according to a third embodiment, in the rest and braking position of said element E.

0031Figure 1 shows a bicycle frame Ç according to the invention. The design of a bicycle frame C which is the subject of the present invention can be applied to any type of frame, rigid or suspension, and to any type of bicycle, whether it be an all-terrain bicycle , road or city. The advantages in terms of reliability, aerodynamics and safety provided by a frame incorporating a braking device according to the invention will particularly interest professionals and passionate amateurs. The aesthetic appeal brought by this integration of the braking device is also likely to interest certain manufacturers of frames wishing to stand out from the competition.

0032A bicycle frame Ç generally comprises at least one fork 10 comprising two branches 12 mounted on either side of a wheel R with rim J, as illustrated by FIGS. 2A, 2B, 4A, 4B, 6A and 6B. Unlike the bicycle frames of the prior art on which various braking devices are attached, a bicycle frame C according to the invention is equipped with a braking device D such that each branch 12 of said fork 10 incorporates at least one braking element E comprising means 14 for securing to the frame Ç, a rigid arm 16 movable relative to said solidαrisαtion means 14 and capable of taking all the positions between two extreme positions of rest and braking, a friction member 18 carried by this arm and designed to cooperate with said wheel rim, as well as 'a link 20 with elastic return interposed between the securing means 14 and the arm 16. For the present application, a fork designates both the front fork and the rear seat stays, wishbone, or base of a bicycle frame, as well as any other part of a cycle frame capable of comprising two arms mounted on either side. other of a wheel. In FIGS. 1, 2A, 2B, AA and 4B, it has been chosen to illustrate a front fork of a bicycle frame according to the invention incorporating a braking device D.

0033In FIGS. 6A and 6B, an example of the rear shrouds of a bicycle frame according to the invention is shown, incorporating a braking device b. In all cases, two braking elements E are therefore located on either side of the rim J of a wheel R and arranged in a substantially symmetrical manner relative to the plane of the wheel R, the friction member 18 carried by each of the rigid arms 16 of these two braking elements E being oriented towards said rim J, this in a known manner.

0034Said friction member 18 carried by the arm 16 is in the form of a pad and is attached to said arm 16 by any suitable means, in particular by screwing, this also in a well-known manner .

0035In order to perform the braking, a braking element E comprises an elastic return link 20 allowing mobility of the rigid arm 16 relative to the securing means 14, ie relative to the frame Ç of the bicycle. The movement of a rigid arm 16 of a braking element E allowed by said elastic return link 20 takes place between two extreme positions:

0036- A so-called rest position of the element E shown in FIGS. 2A, 4A and 6A in which the friction member 18 carried by the arm 16 is distant from the part of the rim J with which it cooperates to perform the braking, and,

0037- a so-called braking position of the element E shown in the figures

00382B, 4B and 6B in which the friction member 18 carried by the arm 16 is supported on the part of the rim J with which it cooperates to effect braking.

0039The movement of a braking element E, and more particularly the bringing together of the two braking elements E in order to effect their passage from their rest position towards their braking position, is caused by the action of operating means not shown. in the various figures since they are well known and are not the subject of the present invention. However, each arm 16 of a braking element E provides means 22 for receiving these maneuvering means retransmitting the action performed by the practitioner on a brake lever for example. These receiving means 22 for the maneuvering means may simply be in the form of a passage 24 produced at the upper end of the arm 16 of each braking element E.

0040The operating means generally comprising a sheath and a cable connected at one end to a brake lever, a passage 24 is of dimensions adapted to allow only the passage of the cable, the sheath having to remain in abutment on the upper end of the arm 16 at right of way 24 so that the maneuvering means can bring the braking elements E belonging to each of the forks 10 closer together. By integrating a braking element E, the invention means that at least part of a braking element E forms an integral part of a part of the branch 12 of a fork 10 of a frame C along the 'invention. To this end, and as illustrated in FIGS. 1, 2A, 2B, AA, 4B, 6A and 6B, each branch 12 of a fork 10 of said frame Ç comprises at least one housing 26 for receiving a braking element E . A receiving housing 26 is in the form of a recess 28 produced in the volume of the branch 12 of the fork 10, substantially in line with the part of a rim J with which the braking member 18 cooperates. preferably, this receiving housing 26 came from manufacture with the fork 10 of a frame Ç according to the invention. According to a first embodiment, in particular illustrated in FIGS. 1, 2A and 2B, a housing 26 for receiving an element E is situated substantially in the transverse median plane of the branch 12 in which said element E is integrated, and, this receiving housing 26 offers a volume containing the securing means 14, the elastic return link 20 and the arm 16 of the element E at least in the braking position of said element E. According to a second embodiment, in particular illustrated in FIGS. AA, 4B, 6A and 6B, a housing 26 for receiving an element E offers a volume containing the securing means 14, the connection 20 with elastic return and the arm 16 in all the positions that said arm 16 can take between the rest position and the braking position of said element E. It can therefore be seen that the integration of the braking device D into a frame Ç according to the invention, in particular thanks to the receiving housing 26, is capable of offering advantageous advantages in terms of aerodynamics of said frame C as well as good protection of said braking device Ç> during a fall of the practitioner or possible natural obstacles such as branches in the case of an application of said frame to mountain bikes.

0041These first advantages of the invention are relayed by those provided by the design of the connection 20 with elastic return interposed between the solidαrisαtion means 14 and the arm 16 of the element E, connection allowing the return of said element E to the position of rest from its braking position. According to a first embodiment illustrated in FIGS. ZA and 2B, the elastic return connection 20 between the securing means 14 and the arm 16 consists of at least one web 30 capable of deforming from a position of rest <img file="WO2008009817A1_D0001.tif" /> a braking position under a force exerted between the securing means 14 and the arm 16 which it connects and resume its initial rest position as soon as said force is released, in particular when the practitioner no longer actuates the maneuvering means. "Veil" is understood to mean at least one zone capable of being deformed by bending, from a determined neutral position, after manufacturing, under a force undergone between the two parts which it connects and returning to its initial neutral position. as soon as said effort is released. Thus, the veil can be thin or thick if the material which constitutes it makes it possible to achieve the desired result of working in bending. However, this elastic return link 20 must withstand the torque experienced during braking.

0042In order to optimize the braking and more particularly to distribute the braking force transmitted by the friction member 18 uniformly over the part of the rim J with which it cooperates, the invention provides a second embodiment of the link 20 with elastic return allowing a substantially translational movement of the friction member 18 during the movement of the braking element E between its two extreme braking and rest positions. Thus, according to a second embodiment of a connection 20 with elastic return, shown in FIGS. 3, 4 A and 4B, the connection 20 with elastic return between the securing means 14 and the arm 16 of the element E is consisting of at least two substantially identical and substantially parallel sails 30 which are liable to deform.

0043More specifically, this second design of an elastic return link 20 made up of two substantially identical webs 30 in thickness, in width and in height, and parallel to each other, allows a substantially identical deformation of said webs under the force transmitted by the means. to maneuver and therefore the translational movement of the arm 16 relative to the securing means 14. This translational movement of the arm 16 and therefore of the friction member 18 makes it possible to optimally align the friction surface of the braking member with the braking surface of the rim, thus distributing the effort as best as possible. braking over the entire braking surface of said rim.

0044The braking thus produced is powerful and very "biting" because it provides maximum and instantaneous recovery of the forces exerted by the torque of the wheel during braking.

0045Such braking is not suitable for all practitioners, some practitioners prefer to have a braking device offering a certain progressiveness.

0046To this end, in a third embodiment, illustrated in FIGS. 6A and 6B, the elastic return connection 20 between the securing means 14 and the arm 16 consists of at least two sails 30 of different heights, relative inclination between 5 and 25 degrees and liable to deform. More specifically, this third design of an elastic return link 20 consisting of two webs 30 of different heights allows, thanks to the different deformations of said webs under the force transmitted by the operating means, to control the instantaneous center of rotation of the arm 16 during of its movement relative to the securing means 14. This control of the instantaneous center of rotation of the arm 16 and therefore of the friction member 18 makes it possible to progressively present the friction surface of the braking member against the braking surface of the rim, thus gradually increasing the force braking on said rim. The fastening means 14 of the braking element E also play an important role vis-à-vis the reliability of the braking device D and the resumption of the torque of the wheel during braking.

0047According to a first embodiment, illustrated in FIGS. 1, ZA₁ 2B and 3, the means 14 for securing the element E to the frame Ç are in the form of a base 32 of said element E fixed to the frame by screwing.

0048A base 32 has a thickness e, a large width _ \ and a height h. Advantageously, in the case of a fixing of the base 32 of the element E only by screwing, at least two fixing points, or two screws, connect said base 32 to the frame Ç so as to block the rotation of said element E in the plane of the wheel R.

0049According to a second embodiment, a variant of which is illustrated in FIGS. 4A and 4B, the means for securing an element E to the frame Ç are in the form of at least one imprint 34 for receiving at least one stop 38 belonging to the frame Ç. A receiving imprint 34 is constituted by a projecting shape made in the thickness e of the base 32 so as to prevent the rotation of the element E in the plane of the wheel R.

0050In the example shown in Figures AA and 4B, the receiving cavity 34 takes the form of a groove 36 made in the thickness e of the base 32 and of length substantially equal to the width I of said base 32 .

0051A stop 38, in particular from manufacturing with the frame Ç, is a relief shape capable of cooperating with the projecting shape of the imprint 34 for reception. In a first variant illustrated in FIGS. 4A and 4B, the means 14 for securing an element E are produced from two receiving cavities 34 located on either side of the thickness e of the base 32 of said base braking element E, the base 32 is thus locked in rotation in the plane perpendicular to the plane of the wheel R. Preferably, the two receiving indentations 34 are located at different heights of the base 32. In a second variant, the means 14 for securing an element E can also be produced from a receiving cavity 34 cooperating with a stop 38 of the frame Ç and from a fixing of the base 32 to the frame Ç in a point by screwing, in particular using a screw.

0052In their third embodiment illustrated in FIGS. 5, 6A and 6B, the means 14 for securing an element E are in the form of a drape 40 of at least part, in particular a part extending the base 32, of said element E. In this case, it is necessary to provide for the integration of the element E in each branch 12 of a fork 10 during its manufacture.

0053In order to allow the production of a braking element E and therefore of an arm 16, of an elastic return link 20, in particular of at least one veil 30, and of fastening means 14 capable of withstanding the forces of braking, the invention preferably provides for making the braking element E in composite material.

0054In this case, the securing means 14, the elastic return link 20 and the arm 16 have come from one-piece manufacture of composite material, more particularly of fibers based on carbon, aramid and / or glass. , embedded in a resin matrix. Thus, in a braking element E made in a single piece of composite material, the securing means 14, the base 32 and the arm 16 can be made from fibers favoring rigidity and lightness, such as carbon fibers , while the elastic return link 20, in particular at least one veil 30, can be produced from fibers favoring elasticity, such as glass fibers.

0055The base 32 and the arm 16 of the braking element E have geometries which are particularly suitable for mechanically resisting the forces generated, as is the elastic return link 20 which must resist the torque undergone during braking.

0056The arrangement of each element E according to the invention, produced in a monolithic piece of composite material, is particularly attractive because the web 30 makes it possible to transmit to the fastening means 14 and therefore to the frame C the torque exerted by the wheel during braking and undergone by the arm 16.

0057The torque is therefore transmitted by the same part of the wheel interface

0058R / braking member 18 to the square Ç.

0059The practitioner who uses this arrangement notes a very great progressiveness during actions on the brake lever because all possible friction, seizure points or mechanical jamming generated by a return spring, are eliminated.

0060The elastic return effort required to maneuver the arm and to bring it back to the neutral position after a braking action is minimal, so that the effort exerted by the practitioner is not only progressive but almost entirely reserved for braking, allowing very precise dosing. . This is all the more true since composite materials using high modulus fibers transmit stresses very faithfully.

0061The progressiveness, the power of the elastic return can be easily adjusted by the profiles, the fibers, their diameters and / or their numbers, the orientations, the nature of the resin constituting the matrix.

0062Such a braking element E also brings an advantage inherent in its nature but far from being negligible in the field of the cycle: the weight. Thanks to its realization in a monolithic piece of composite material, a braking element E is likely to have come from manufacturing with the fork 10 which integrates it. The advantages mentioned above are then even greater and the integration of the braking element E is complete.