ADJUSTABLE SHOCK ABSORBER FOR A BICYCLE

Description

Domaine Technique

[0001] The present invention relates to the field of adjustable suspensions for bicycles and in particular suspensions whose preload can be adjusted. Such suspensions can be fitted to a bicycle fork or shock absorber.

[0002] Suspension preload is also called SAG, and is the amount of suspension sag relative to the rider's weight. Preload is usually a percentage of the suspension's total travel between a compressed and uncompressed position. The correct preload is different for every rider and should therefore be set before using the bike. Technique antérieure

[0003] There are known mechanical spring bicycle suspensions in which the preload is adjusted by adjusting the stress exerted on the spring at rest. A disadvantage of these suspensions is that the mechanical spring is generally very heavy and does not offer a sufficiently large preload adjustment range. Also, it is sometimes necessary to change the mechanical spring depending on the user's weight.

[0004] Air suspensions are also known in which the preload is adjusted by adjusting the air pressure in the suspension.

[0005] The pressure is usually adjusted manually using a hand air pump. This involves a trial-and-error pressure adjustment procedure, which usually requires repeatedly injecting air into the suspension and then expelling air from the suspension.

[0006] The preload adjustment procedure then involves a significant and tedious repetition of steps in order to obtain the desired preload.

[0007] Furthermore, document EP2573420 discloses a suspension comprising a first chamber, a secondary chamber and a movable control element enabling the first chamber to be placed in alternate communication with the secondary chamber and the secondary chamber with the exterior of the suspension, in order to progressively reduce the pressure of the first chamber.

[0008] The pressure in the first chamber is therefore initially raised to an excessive value and then reduced manually and by trial and error by the user, until a pre-stressing that seems suitable is reached.

[0009] A disadvantage of this suspension is that the user must estimate for himself when the preload seems satisfactory and he is not guided in this adjustment. He therefore cannot adjust the preload to a value adapted to his own weight. Adjusting the preload is particularly long, difficult and imprecise.

[0010] Furthermore, if the pressure in the first chamber becomes insufficient, the user must inject air into the suspension again and repeat the manual preload adjustment actions, which is very restrictive.

[0011] Documents EP 2 450 591 A2 and EP 2 404 818 A1 each disclose an adjustable suspension for a bicycle. Exposé de l'invention

[0012] An object of the present invention is to provide an adjustable suspension for a bicycle which overcomes the aforementioned problems.

[0013] To this end, the invention relates to an adjustable suspension for a bicycle, comprising:a suspension body having a main fluid inlet configured to inject fluid into the suspension body, and a fluid outlet;a piston disposed in the suspension body and comprising a piston head defining a first chamber and a second chamber within said suspension body, the first chamber being in fluid communication with the main fluid inlet, the piston being movable in translation in the suspension body between: at least a first position in which the fluid outlet is in fluid communication with the second chamber but not with the first chamber, so as to deploy the piston, and at least a second position in which the fluid outlet is in fluid communication with the first chamber so that fluid injected through the main fluid inlet is guided toward the fluid outlet, in order to evacuate the injected fluid from the suspension, the piston being configured to move from the first position to the second position when fluid is injected through the main fluid inlet;and a valve device capable of assuming a first state in which it prevents fluid from escaping from the suspension, and a second state in which it allows extraction of the fluid from the suspension, the valve device being configured to be brought into the second state when fluid is injected through the main fluid inlet and to be brought into the first state when fluid injection is interrupted. ;

[0014] Without departing from the scope of the invention, the suspension may be a front suspension or a rear bicycle suspension. In a non-limiting manner, it may be an air and / or hydraulic suspension.

[0015] The main fluid inlet can be connected to a pump or a fluid cartridge to inject fluid into the suspension. The fluid outlet opens out of the adjustable suspension. The main fluid inlet communicates with the first chamber when the piston is in the first position and when it is in the second position.

[0016] The suspension body advantageously comprises a first base defining with the piston head said second chamber. The suspension body advantageously comprises a second base defining with the piston head said first chamber. Alternatively and in a non-limiting manner, the second base may be formed by a separate element connected to the suspension body.

[0017] The translational movement of the piston in the suspension body has the consequence of modifying the volume of the first chamber and the second chamber.

[0018] To adjust the suspension preload, the user mounts the bike, so as to exert their weight on the suspension in order to compress it and extract at least some of the fluid. The piston is moved to the second bottom and is placed in the first position.

[0019] Without limitation, in the first position, the first chamber may be completely emptied of fluid or still contain a small amount of fluid.

[0020] The user then injects fluid, such as air, gas, or liquid, through the main fluid inlet. The suspension is configured so that the fluid injected through the main fluid inlet is fed into the first chamber.

[0021] In this first position, the piston prevents fluid communication between the main fluid inlet and the fluid outlet. In other words, the piston prevents the passage of fluid injected through the main fluid inlet to the fluid outlet. In addition, the piston, the main fluid inlet, and the suspension body are preferably configured so that the fluid remains in the first chamber while the piston is in the first position.

[0022] In this first position, the first chamber and the second chamber are also not in fluid communication.

[0023] The first chamber does not empty when fluid is injected through the main fluid inlet. One advantage is that it allows the preload to be adjusted solely by injecting the fluid.

[0024] This injection of fluid has the effect of gradually increasing the pressure in the first chamber and therefore the preload (or SAG) of the suspension. The injected fluid also exerts a force on the piston so that the latter is deployed and moves away from the second bottom of the suspension body. The fluid injected through the main fluid inlet is preferably kept in the first chamber.

[0025] The piston is moved in translation within the suspension body to a second position. The piston is then positioned so that the fluid outlet is in fluid communication with the first chamber and thus so that the main fluid inlet and the fluid outlet are in fluid communication. The fluid injected through the main fluid inlet is therefore guided to the fluid outlet and is discharged from the adjustable suspension.

[0026] In the second position, if fluid injection is continued, the injected fluid is not held in the first chamber. Fluid injected through the main fluid inlet while the piston is in the second position is guided directly to the fluid outlet.

[0027] Preferably, the injected fluid passes through the first chamber before being guided to the fluid outlet, so that it does not remain in the first chamber.

[0028] In this second position of the piston, the pressure in the first chamber no longer increases and remains constant despite the injection of fluid. In this second position, the preload no longer changes and is set to a value adapted to the user. In addition, the piston remains substantially stationary.

[0029] Thanks to the invention, when the piston reaches the second position, the preload is maintained at a constant value, so that its adjustment is interrupted, even if fluid continues to be injected through the main fluid inlet. The user is then not required to adjust the preload by trial and error. When the piston is in the second position, the preload is set precisely and the user does not need to carry out additional manual tests and adjustments. In addition, since the user rides the bicycle during the adjustment, the set preload is a function of his or her weight.

[0030] Furthermore, the invention makes it possible to avoid the risk of introducing too much fluid pressure into the first chamber, which would force the user to empty the fluid present in the first chamber before injecting more fluid via the main fluid inlet.

[0031] The preload of the adjustable suspension according to the invention can therefore be adjusted quickly and precisely.

[0032] The user can then interrupt the fluid injection and close the main fluid inlet and the fluid outlet. The user then dismounts the bicycle, so as to no longer exert his weight on the suspension. The suspension is then no longer constrained by the user's weight. Due to the pressure of the fluid present in the main chamber, a force is exerted on the piston, tending to further extend the piston away from the second bottom. The piston is brought into a third position, forming a rest position, in which said piston is substantially fully extended.

[0033] Therefore, when the user gets on the bike, the piston is translated from the third position to the second position and the piston stroke between these third and second positions corresponds to the preload set previously.

[0034] Advantageously, the volume of the first chamber when the piston is in the first position is less than the volume of the first chamber when the piston is in the second position. The suspension is adjusted by fluid injection, gradually increasing the volume of the first fluid chamber to move the piston from the first position to the second position. Also, it is not necessary to inject an excessive amount of fluid and then gradually release fluid until the desired preload is reached. One advantage is to limit the amount of fluid consumed.

[0035] According to a particularly advantageous aspect of the invention, the piston is configured to move from the first position to the second position when fluid is injected through the main fluid inlet. The fluid injected into the first chamber moves the piston from the first position to the second position automatically, without additional user intervention. One advantage is that it eliminates the need for a manual preload adjustment step. The user can set the SAG to the appropriate value only by injecting the fluid, so that the preload adjustment is made easier. The movement from the first position to the second position is automatic by injecting the fluid through the main fluid inlet. In particular, it is not necessary to inject an excessive amount of fluid and then open an exhaust valve to release the fluid.

[0036] Thanks to the invention, the preload adjustment is therefore particularly fast. In addition, the SAG is precisely adjusted and maintained at the appropriate value.

[0037] Preferably, the suspension body comprises an injection orifice communicating fluidically with the main fluid inlet and opening into the first chamber, and an evacuation orifice communicating fluidically with the fluid outlet and opening into the suspension body.

[0038] Regardless of the position of the piston, the fluid injected through the main fluid inlet is brought into the first chamber via the injection port.

[0039] In the second position, the first chamber is in fluid communication with the discharge port. The fluid injected through the main fluid inlet via the injection port then passes through the discharge port and is guided to the fluid outlet, so as to escape from the suspension.

[0040] Advantageously, the piston is movable in a direction of movement and the discharge orifice and the injection orifice are arranged in distant positions considered in said direction of movement. The piston therefore describes a relative translational movement with respect to the discharge orifice.

[0041] The discharge port is preferably disposed at a lower portion of the suspension body while the injection port is disposed at an upper portion of the suspension body.

[0042] In the first position, the piston head advantageously extends between the injection port and the discharge port.

[0043] Preferably, the discharge orifice and / or the injection orifice are provided in a side wall of the suspension body. Alternatively, the injection orifice may be provided in the first bottom of the suspension body or the second bottom of the suspension body, possibly formed by an element connected to the suspension body.

[0044] Advantageously, said discharge orifice opens into a discharge chamber fluidly communicating with the fluid outlet. The discharge chamber may comprise a conduit extending between the discharge orifice and the fluid outlet. This discharge chamber makes it possible to bring the fluid leaving the suspension body to the fluid outlet.

[0045] According to a first advantageous variant, the discharge orifice is configured so as to open into the second chamber when the piston is in the first position and so as to open into the first chamber when the piston is in the second position.

[0046] When the piston is in the first position, the piston head extends between the injection port and the discharge port. It then forms a hermetic plug in the suspension body preventing the passage of fluid from the first chamber to the discharge port, so that the injected fluid is retained in the first chamber.

[0047] When moving from the first position to the second position, the piston head passes beyond said discharge orifice so that the discharge orifice is then located between the piston head and the injection orifice and therefore opens into the first chamber.

[0048] In the second position, the main fluid inlet, the first chamber, the discharge port and the fluid outlet are in fluid communication, so that fluid injected through the main fluid inlet is guided to the fluid outlet.

[0049] According to a second advantageous variant, the discharge orifice opens into the second chamber and the piston head extends between the discharge orifice and the injection orifice when the piston is in the second position. The discharge orifice opens into the second chamber regardless of the position of the piston.

[0050] In the first position of the piston, the piston head forms a hermetic plug inside the suspension body, preventing the passage of fluid between the first chamber and the second chamber and therefore between the main fluid inlet and the fluid outlet.

[0051] Preferably, the adjustable suspension comprises a bypass channel configured to place the first and second chambers in fluid communication when the piston is in the second position. One advantage is to place the first chamber and the second chamber, and therefore the main fluid inlet and the fluid outlet, in fluid communication when the piston is in the second position. Another advantage is to balance the pressures between the first chamber and the second chamber.

[0052] Without limitation, the bypass channel may be provided in the suspension body or in the piston.

[0053] Advantageously, the suspension body comprises an inner wall and the bypass channel is formed in said inner wall, the piston head being positioned at the bypass channel when the piston is in the second position, so that, in this second position, the first and second chambers are in fluid communication.

[0054] The piston head advantageously has a thickness considered according to the direction of movement of the piston. Similarly, the bypass channel advantageously has a length considered according to said direction of movement of the piston. The length of the bypass channel is preferably greater than the thickness of the piston head.

[0055] Also, when the piston is in the second position and therefore when the piston head is arranged at the bypass channel, said bypass channel opens into the suspension body, on either side of the piston head, respectively into the first chamber and into the second chamber. Said bypass channel then forms a passage allowing the fluid to bypass the piston and pass from the first chamber to the second chamber, in order to be guided towards the fluid outlet. The main fluid inlet and the fluid outlet are therefore placed in fluid communication.

[0056] When the piston is in the first position, the bypass channel extends into the second chamber so that it does not allow fluid communication between the first chamber and the second chamber.

[0057] Preferably, considered in the direction of movement of the piston, the bypass channel extends between the discharge port and the injection port.

[0058] Advantageously, the adjustable suspension further comprises a valve device capable of assuming a first state in which it prevents fluid from escaping from the suspension, and a second state in which it allows fluid to be extracted from the suspension.

[0059] It is understood that the valve device is placed in the second state when the preload is adjusted, in order to allow the fluid to be evacuated when the piston is in the second position. The valve device is advantageously placed in the first state when the preload is adjusted, so that this first state corresponds to a normal operating state of the suspension, without adjustment. In this first state, the fluid device makes it possible to maintain the fluid in the suspension so that the preload remains substantially constant and adjusted to a value suitable for the user.

[0060] Preferably, the valve device comprises an inlet valve disposed at the main fluid inlet and an outlet valve disposed at the fluid outlet, said inlet and outlet valves being configured to open when the valve device is in the second state and to close when the valve device is in the first state.

[0061] Without departing from the scope of the invention, the inlet valve may be positioned near the main fluid inlet. In a non-limiting manner, it may be arranged in an injection channel communicating with the main fluid inlet and with the first chamber.

[0062] When the valve device is placed in the second state, both the inlet and outlet valves are open. The opening of the inlet and outlet valves can be simultaneous or successive. Fluid can then be injected and can escape from the suspension. When the valve device is in the first state, the inlet and outlet valves effectively prevent fluid from escaping from the suspension via the main fluid inlet and via the fluid outlet. The preload is maintained all the more effectively at the set value.

[0063] Advantageously, the valve device is configured to be brought into the second state when a fluid is injected through the main fluid inlet and to be brought into the first state when the fluid injection is interrupted.

[0064] An advantage is that the user is not required to manually bring the valve device into the second state when he wishes to adjust the preload. Furthermore, the user is also not required to manually bring the valve device into the first state when the preload is adjusted. In addition, this conformation eliminates the risk of forgetting to return the valve device to the first state, which would impair the operation of the suspension.

[0065] The invention also relates to a method of adjusting an adjustable suspension as described above, comprising the following steps: the first chamber is placed in fluid communication with the atmosphere; the suspension is compressed so as to evacuate the fluid from the first chamber and place the piston in the first position; and the fluid is injected into the first chamber through the main fluid inlet of the suspension body so as to move the piston into its second position, in which the fluid injected through the main fluid inlet is guided to the fluid outlet; and the fluid injection is interrupted and the main fluid inlet and the fluid outlet are closed so that the fluid remains in the suspension

[0066] The invention further relates to a bicycle comprising at least one adjustable suspension as described above. Brève description des dessins

[0067] [ Fig. 1 ] There figure 1 is a sectional view of a first embodiment of the adjustable suspension according to the invention; [ Fig. 2 ]There figure 2 illustrates a fluid distribution device of the adjustable suspension of the figure 1 , in which the outlet valve is closed; [ Fig. 3 ] There figure 3 illustrates the fluid distribution device of the adjustable suspension of the figure 1 , in which the outlet valve is open; [ Fig. 4 ] There figure 4 illustrates the adjustable suspension of the figure 1 , the piston being in a first position; [ Fig. 5 ] There figure 5 illustrates the adjustable suspension of the figure 1 , the piston being in a second position; [ Fig. 6 ] There figure 6 illustrates the adjustable suspension of the figure 5 after interruption of fluid injection; [ Fig. 7 ] There figure 7 illustrates the adjustable suspension of the figure 1 , the piston being placed in a third position; [ Fig. 8 ] There figure 8 is a sectional view of a second embodiment of the adjustable suspension according to the invention, the piston being placed in a first position; [ Fig.9 ] There figure 9 illustrates the adjustable suspension of the figure 8 , the piston being placed in a second position; and [ Fig. 10 ] There figure 10 illustrates a bicycle equipped with adjustable suspension according to the invention. Description des modes de réalisation

[0068] The invention relates to an adjustable suspension of a bicycle whose preload can be easily adjusted, depending on the weight of the user.

[0069] There figure 1 illustrates an adjustable suspension 10 in accordance with the present invention.

[0070] Adjustable suspension 10 forms in this non-limiting example a rear bicycle suspension. It comprises a suspension body 12 and a piston 14 arranged in the suspension body.

[0071] The suspension body 12 includes a main cylinder 13 delimiting a master bedroom. It includes a side wall 16 a first background 18 in the lower part of the suspension body. The suspension body 12 further comprises a fluid dispensing device 20, attached to the main cylinder 13 and delimiting a second background 22 in the upper part of said suspension body.

[0072] On this figure 1 , we see that the piston 14 includes a piston rod 24 and a piston head 26 attached to the piston rod. We note that the piston 14 is arranged inside the main cylinder 13 of the suspension body 12 and delimits with the second background 22 a first bedroom 28 inside said suspension body 12. The piston head 26further delimits a second bedroom 30 with the first background 18, inside the suspension body 12. The piston rod 26 extends in a direction of movement X in the suspension body, so that the piston 14 is mounted sliding in this direction of movement X inside the suspension body 12.

[0073] The fluid distribution device 20 is integral with the main cylinder. In this non-limiting example, the fluid distribution device and the main cylinder 13 form two separate parts, the fluid distribution device being secured to an upper part of the cylinder. Alternatively, the suspension body can form a single-piece assembly.

[0074] The suspension body 12 includes a main fluid inlet 31arranged in the upper part of said suspension body. The suspension body also comprises a fluid outlet 32 arranged on the fluid distribution device 20. The fluid outlet 32 emerges from the adjustable suspension 10.

[0075] Adjustable suspension 10 also includes a secondary cylinder 34, inside which the main cylinder extends 13 and defining with the side wall 16 an evacuation chamber 36. The evacuation chamber 36 is in fluid communication with the fluid outlet 32.

[0076] The suspension body includes a drain port 38 arranged in the side wall 16 of said suspension body 12, so that said discharge orifice 38 opens inside the main cylinder 13of the suspension body and in the evacuation chamber 36. The drain hole 38 is in fluid communication with the fluid outlet 32.

[0077] The suspension body 12 does not include an injection port elsewhere 40, provided in the fluid distribution device 20 and opening into the first bedroom 28 of the suspension body 12.

[0078] The injection port 40 is in fluid communication with the main fluid inlet 31.

[0079] The fluid distribution device 20 includes a valve cavity 42 cylindrical, arranged in said fluid distribution device 20. The fluid distribution device further comprises an injection channel 48, a drainage channel 50 and a valve channel 52.

[0080] The injection channel 48 is provided in the fluid distribution device 20. It opens into the first room 28 via the injection port 40. In this non-limiting example, the injection channel 48 includes three channel segments.

[0081] The fluid distribution device 20 further comprises a valve device 41 including an inlet valve 46, forming a non-return valve, fitted with a spring. The inlet valve 46 is slidably mounted in the injection channel at the main fluid inlet 31. The inlet valve 46 can take a closed position, illustrated in figure 1 , in which it prevents a fluid from entering or escaping from the injection channel 48 and therefore of the first room 28and an open position in which it allows the introduction of a fluid into the injection channel 48 and in the first room 28. The first spring 47 tends to bring the inlet valve 46 in the closed position. The inlet valve is further configured to open and allow fluid to enter the first chamber 28 when the pressure of said fluid upstream of said non-return valve is greater than a predetermined pressure threshold.

[0082] The drainage channel 50 is in fluid communication with the evacuation chamber 36 and with the outside of the suspension. The exhaust channel passes through the valve cavity 42, so that it comprises a first portion of evacuation channel 50a opening into the evacuation chamber 36 and in the valve cavity 42 and a second portion of drainage channel 50bopening into the valve cavity 42 and out of suspension.

[0083] The valve device 41 includes an outlet valve 44 equipped with a second spring 45 and slidably mounted in the valve cavity 42, along a sliding axis Y. The outlet valve 44 comprises a first cylindrical valve part 44a and a second cylindrical valve part 44b. The outlet valve 44 can take a closed position, illustrated in figure 1 , in which it prevents fluid from escaping from the suspension body 12 and suspension 10, and an open position in which it allows fluid to escape from the suspension body 12 and suspension 10. The second spring 45 tends to bring the outlet valve to the closed position. The outlet valve 44is further configured to open when the pressure of said fluid upstream of said outlet valve is greater than a predetermined pressure threshold.

[0084] In this non-limiting example, the suspension body 12 also includes a removable cap 54 mounted at the upper end of the fluid distribution device 20 and in which the main fluid inlet is provided 31. An interior accommodation 56 is provided in this removable cap 54. The valve canal 52 opens on the one hand into the valve cavity 42 and on the other hand in the interior housing 56 of the cork 54.

[0085] With the help of the figures 1à 7 , we will detail the steps for adjusting the preload of the adjustable suspension 10 described previously.

[0086] First, the first room 28is substantially emptied of fluid, for example by removing the removable plug 54. The user then gets on the bike, so as to compress the adjustable suspension.

[0087] As long as no fluid is injected, the valve device 41 is placed in a first state, in which the inlet valve 46 and the outlet valve 44 are closed, as illustrated in figure 2 . In the closed position, the outlet valve closes the valve channel 52. Furthermore, in the closed position, the outlet valve 44 is arranged so that the first portion of the discharge channel 50a and the second portion of the drainage channel 50b open on either side of said second cylindrical valve part 44b. The second part of the cylindrical valve 44b forms a shutter in the valve cavity 42preventing fluid from the first portion of the discharge channel 50a to be brought into the second portion of the evacuation channel 50b and thus escape from suspension.

[0088] In this non-limiting example, the user then connects the removable plug 54 to the suspension.

[0089] The user then injects a fluid, for example a gas such as carbon dioxide, through the main fluid inlet 31 placed on the removable cap 54, as illustrated in figure 2 . The fluid can be contained in a cartridge. Alternatively, the user can connect a pump to the main fluid inlet. The fluid flow is illustrated by arrows. The fluid then enters the housing 56 of the removable plug. The pressure of the injected fluid, upstream of the inlet valve 46 of the valve device 41,is insufficient to allow the inlet valve to open 46 and therefore the entry of the fluid into the main chamber 28. The fluid is guided through the valve channel 52 towards the valve cavity 42.

[0090] The valve device being in a first state, the outlet valve is closed. The injection of fluid has the effect of moving the outlet valve 44 along the sliding axis Y, to the open position shown in figure 3 . Fluid injection helps maintain the outlet valve 44 in open position

[0091] In this open position, the second spring 45 is compressed. The first portion of the discharge channel 50a and the second portion of the drainage channel 50b open on the same side of the second part of the cylindrical valve 44b and are therefore in fluid communication.

[0092] The injection of fluid is continued so that the pressure within the valve channel 52 and housing 56 arranged in the removable cap 54 gradually increases. When the pressure in the valve channel 52, in the accommodation 56 and therefore upstream of the inlet valve 46 becomes greater than the predetermined pressure threshold for opening said inlet valve 46, the latter opens and allows the fluid to enter the injection channel 48 then in the first room 28. This step is illustrated in figure 4 . The inlet and outlet valves 46,44 are then opened. The valve device 41 is therefore automatically brought into a second state by injection of fluid via the main fluid inlet 28. In this second state, the valve device 41 allows the extraction of fluid from the suspension.

[0093] The pressure in the first chamber 28 increases due to the fluid entering it.

[0094] There figure 4 illustrates the piston in a first position, in which the piston head 26 is arranged at a distance d1 from the second background 22 of the suspension body 12. In addition, the drain hole 38 opens into the second bedroom 30, so that the fluid outlet 32 communicates fluidly with the second chamber 30 but not with the first room 28. Also, the fluid injected through the main fluid inlet 31 in the first room 28 exerts a force on the piston head 26, oriented in the direction of travel, in a direction opposite to the main fluid inlet 31. The piston 14 is moved into the suspension body 12in the said direction, according to the direction of movement X and is deployed. The volume of the first chamber increases. The distance between the second bottom 22 of the suspension body 12 and the piston head 26 increases. Also, the volume of the first chamber 28 increase.

[0095] As we notice from the passage of the figure 4 to the figure 5 , the piston 14 is moved, until the piston head 26 passes beyond the drain hole 38. From then on, the drain hole 38 no longer opens into the second bedroom 30 but in the first room 28. The piston 14 is then placed in a second position in which the piston head 26 and the second background 22 of the suspension body are separated by a distance d2 greater than the initial distance d1.

[0096] Thanks to the invention, the piston 14 therefore moves from the first position to the second position automatically, by continuous injection of fluid through the main fluid inlet 31.

[0097] In this second position of the piston 14, illustrated in figure 5 , the fluid outlet 32 is in fluid communication with the first chamber 28. The fluid injected through the main fluid inlet 31 is brought into the first room 28 then into the discharge chamber via the discharge port. The fluid is then brought into the first portion of the discharge channel 50a, in the valve cavity 42 then in the second portion of the evacuation channel 50b and is finally guided out of the adjustable suspension 10 via the fluid outlet 32.

[0098] In this second position of the piston 14,the main fluid inlet 31 is in fluid communication with the fluid outlet 32 so that the injected fluid is discharged out of the adjustable suspension 10 through said fluid outlet. As a result, the pressure within the first chamber 28 no longer increases and the piston 24 is no longer moved in the suspension body 12, despite the injection of the fluid.

[0099] The suspension preload is then adjusted and no longer changes, despite the continued injection of fluid through the main fluid inlet 31. Also, thanks to the invention, the prestress is adjusted very easily, by injecting the fluid continuously through the main fluid inlet. 28. The user is not required to adjust the preload manually, for example by trial and error.

[0100] As the user is positioned on the bike during adjustment, the second piston position 14 is conditioned by the user's weight. Also, the preload, or SAG, is adjusted according to the user's weight.

[0101] As illustrated in figure 6 , the user then interrupts the injection of fluid, which no longer exerts force on the inlet and outlet valves. The first spring 47 brings the inlet valve to the closed position and the second spring 45 brings the outlet valve to the closed position. Interrupting fluid injection therefore automatically brings the valve device 41 in the first state in which it prevents fluid from escaping from the suspension.

[0102] Additionally, the pressure in the first chamber decreases slightly so that the piston is moved slightly towards the main fluid inlet. The exhaust port 38is then placed at the level of the piston head 26 and no longer opens into the first room 28. The piston head 26 seals the drain hole so that fluid does not escape from the first chamber.

[0103] The user can then get off the bike. Due to the pressure exerted by the fluid present within the first chamber 28 and the removal of the user's weight, the piston 14 is further deployed to a third position, which corresponds to a rest position of the adjustable suspension.

[0104] In this third position, illustrated in figure 7 , the piston head 26 and the second background 22 of the suspension body 12 are separated by a distance d3 greater than the initial distance d1 and at a distance d2 . The piston stroke 14between these second and third positions corresponds to the preload set previously. In this non-limiting example, the piston head 26 is substantially in contact with the first bottom 18. Without departing from the scope of the invention, in the third position, a quantity of fluid may remain in the second chamber 30; so that the volume of the second chamber is non-zero and the piston head is kept at a distance from the first bottom.

[0105] The user can then detach the removable cap 54 of the suspension body 12, which results in the valve channel being 52 in fluid communication with the atmosphere. One advantage is to empty any fluid that may be present in the valve channel 52. The inlet valve 46 , which is closed, keeps the fluid present in the first chamber 28.The bulk and weight of the suspension are therefore reduced by removing the removable cap 56.

[0106] There figure 8 illustrates a second embodiment of the adjustable suspension according to the invention. In this second embodiment, the discharge orifice 38' is located near the first bottom 18. The suspension body further includes a bypass channel 60 arranged in its side wall 16. Considered according to the direction of movement X of the piston 14, the bypass channel 60 has a length greater than the thickness of the piston head, also considered in this direction.

[0107] When the piston 14 is in the first position and in the second position, the discharge port 38' opens into the second chamber, so that the piston head extends between the discharge port 38'and the injection port 40.

[0108] The bypass channel 60 is positioned so that when the piston 14 is in the first position, illustrated in figure 8 , the piston head 26 extends between the injection port 40 and the bypass channel 60. Also, in the first position of the piston 14, the bypass channel 60 opens into the second bedroom 30 but not in the first room 28. The injection of fluid results in deploying the piston, as in the first embodiment, to a second position.

[0109] When the piston 14 is in the second position, illustrated in figure 9 , the piston head 26 is located at the bypass channel 60, so that said bypass channel opens into the suspension body12, on either side of the piston head, respectively in the first chamber 28 and in the second room 30. Said bypass channel then forms a passage allowing the fluid to bypass the piston head 26 and to pass from the first chamber to the second chamber. The first chamber and the second chamber are then in fluid communication.

[0110] Also, as illustrated in figure 9 , when the piston is in the second position, the fluid injected through the main fluid inlet 31 passes from the first chamber to the second chamber and is then guided to the fluid outlet via the discharge port 38', the evacuation chamber 36, the drainage channel 50 and the valve cavity 42.

[0111] There figure 10 illustrates a bicycle 100 equipped with adjustable suspension 10according to the invention. In this non-limiting example, the adjustable suspension is a rear suspension of the bicycle.

Claims

1. An adjustable suspension (10) for a bicycle, comprising: - a suspension body (12) provided with a main fluid inlet (31) configured to inject a fluid into the suspension body, and with a fluid outlet (32); - a piston (14) disposed in the suspension body and comprising a piston head (26) delimiting a first chamber (28) and a second chamber (30) inside said suspension body, the first chamber being in fluid communication with the main fluid inlet, the piston being movable in translation in the suspension body between: at least one first position in which the fluid outlet fluidly communicates with the second chamber but not with the first chamber, so as to deploy the piston, and at least one second position in which the fluid outlet is in fluid communication with the first chamber so that the fluid injected through the main fluid inlet is guided to the fluid outlet, in order to evacuate the injected fluid from the suspension, the piston (14) being configured to move from the first position to the second position when fluid is injected through the main fluid inlet (31); and - a valve device (41) which can assume a first state in which it prevents fluid from escaping from the suspension, and a second state in which it allows the extraction of the fluid from the suspension, characterized in that the valve device (41) is configured to be brought into the second state when a fluid is injected through the main fluid inlet (31) and to be brought into the first state when the fluid injection is interrupted2. The adjustable suspension according to claim 1, wherein the volume of the first chamber (28), when the piston (14) is in the first position, is less than the volume of the first chamber when the piston is in the second position.

3. The adjustable suspension according to claim 1 or 2, wherein the suspension body (12) comprises an injection orifice (40) fluidly communicating with the main fluid inlet (31) and opening into the first chamber (28), and an evacuation orifice (38) fluidly communicating with the fluid outlet (32) and opening into the suspension body.

4. The adjustable suspension according to claim 3, wherein the piston (14) is movable in a direction of displacement (X), and wherein the evacuation orifice (38) and the injection orifice (40) are disposed in distant positions considered in said direction of displacement.

5. The adjustable suspension according to claim 4, wherein the evacuation orifice (38) and / or the injection orifice (40) are formed in a side wall of the suspension body.

6. The adjustable suspension according to any one of claims 3 to 5, wherein said evacuation orifice (38) opens into an evacuation chamber (36) fluidly communicating with the fluid outlet (32).

7. The adjustable suspension according to any one of claims 3 to 6, wherein the evacuation orifice (38) is configured so as to open into the second chamber (30) when the piston (14) is in the first position, and so as to open into the first chamber (28) when the piston is in the second position.

8. The adjustable suspension according to any one of claims 3 to 6, wherein the evacuation orifice (38') opens into the second chamber (30), and wherein the piston head (26) extends between the evacuation orifice (38') and the injection orifice (40) when the piston (14) is in the second position.

9. The adjustable suspension according to claim 8, comprising a bypass channel (60) configured to fluidly communicate the first and second chambers (28,30) when the piston (14) is in the second position.

10. The adjustable suspension according to claim 9, wherein the suspension body (12) comprises an inner wall (16), and wherein the bypass channel (60) is formed in said inner wall, the piston head (26) being positioned at the bypass channel when the piston (14) is in the second position, so that, in this second position, the first and second chambers (28,30) are in fluid communication.

11. The adjustable suspension according to claim 4 in combination with claim 9 or 10, wherein, considered in the direction of displacement (X) of the piston (14), the bypass channel (60) extends between the evacuation orifice (38') and the injection orifice (40).

12. The adjustable suspension according to any one of claims 1 to 11, wherein the valve device (41) comprises an inlet valve (46) disposed at the main fluid inlet (31) and an outlet valve (44) disposed at the fluid outlet (32), said inlet and outlet valves being configured to open when the valve device is in the second state and to close when the valve device is in the first state.

13. The adjustable suspension according to any one of claims 1 to 12, wherein the fluid is a gas, for example carbon dioxide.

14. A method for adjusting an adjustable suspension (10) for a bicycle, comprising: - a suspension body (12) provided with a main fluid inlet (31) configured to inject a fluid into the suspension body, and with a fluid outlet (32); - a piston (14) disposed in the suspension body and comprising a piston head (26) delimiting a first chamber (28) and a second chamber (30) inside said suspension body, the first chamber being in fluid communication with the main fluid inlet, the piston being movable in translation in the suspension body between: at least one first position in which the fluid outlet fluidly communicates with the second chamber but not with the first chamber, so as to deploy the piston, and at least one second position in which the fluid outlet is in fluid communication with the first chamber so that the fluid injected through the main fluid inlet is guided to the fluid outlet, in order to evacuate the injected fluid from the suspension, the method comprising the following steps: - the first chamber (28) is fluidly communicated with the atmosphere; - the suspension is compressed so as to evacuate the fluid from the first chamber and place the piston (14) in the first position; and - the fluid is injected into the first chamber through the main fluid inlet (31) of the suspension body (12) so as to displace the piston to its second position, in which the fluid injected through the main fluid inlet is guided to the fluid outlet (32); and - the fluid injection is interrupted and the main fluid inlet and the fluid outlet are closed so that the fluid remains in the suspension.

15. A bicycle including at least one adjustable suspension (10) according to any one of claims 1 to 13.