Improvements in an air spring

Abstract

The present invention provides an air spring (10) comprising: a pressurised, gaseous, springing medium (G) contained within; a main chamber (12), fluidly connected to each of, two or more adjustment chambers (20), at a sealable port (30); the main chamber (12) including a load bearing surface (14), arranged to transmit a force (F) from a load, in use to the springing medium G; wherein the sealable connection port (30) includes a sealing means (32) for discreetly isolating the main chamber (12) from each of the one or more adjustment chambers (20) and one or more of the chambers (12, 20) contain a mass of adsorptive material (40) for increasing the effective volume thereof.

Description

[0001] IMPROVEMENTS IN AN AIR SPRING

[0002] Field

[0003] This invention relates to vehicle suspension systems and devices, and particularly to vehicle suspension systems and devices having an air spring with adjustable and / or tuneable characteristics.

[0004] Background

[0005] Air springs are widely used in vehicle suspension including bicycles and motorcycles and can come in many forms, but all operate on the same principle. A column of gas, usually air but often nitrogen is confined within a chamber which can be compressed along one or more axis. The gas pressure within the chamber determines the force that the spring exerts, and the rate of change of pressure with excursion determines the rate of change of force exerted. This defines the “spring rate”, or stiffness of the spring. The chamber may take the form of a reinforced rubber bellows as can be seen on an HGV, but in the case of bike suspension, it usually takes the form of a cylindrical chamber surrounded by a second telescopic housing which bears on the gas via a piston surrounded by a lubricated, air-tight dynamic seal.

[0006] Standard air springs are lighter than coil springs and are infinitely tuneable to account for loading, but they can have less desirable operating characteristics. The spring rate or stiffness of a coil spring is perfectly linear, while the stiffness of an air spring can be firm at the beginning of travel, and very firm indeed toward the end of travel. The air chamber of an air spring is pressurized and at the start of compression, the load is pushing against the fully pressurized air spring providing a high load before the spring will move. Thus in comparison to a coil spring, where there is little initial resistance felt unless the spring has been significantly preloaded an air spring can be initially very stiff. Efforts have been made to increase the initial suppleness of air spring suspension by adding a negative spring which can be either an air or coil spring. The negative spring in a motorcycle / bicycle fork, for example, puts pressure on the air piston from the opposite or rear side of it to cancel out the positive air pressure during the initial compression and travel of the fork. At rest, a fork with equal pressure in the positive and negative chamber should theoretically feel like a coil and need little loading pressure to initiate fork travel.

[0007] Changing the handling characteristics of a vehicle is desirable. This may be to accommodate different use cases such as change in loading of the vehicle or transition from a comfort setting to a performance setting. It is well known to achieve such changes using damping. However, damping and spring rate work together to provide optimum settings, referred to as a damping ratio, for a particular mass. A damping ratio is normally optimised for minimising contact patch load variation for performance or for minimising accelerative loads on the suspended mass for comfort. Therefore, manufacturers carefully select spring and damper rates to work together. Changing damping alone unavoidably moves the relative damper rate in comparison to the spring rate which can move the system away from the desired ratio. Damping also only changes dynamic forces i.e. when the suspension is in motion. It is often desirable to change spring rate alone or in tandem with damping to arrive at a preferred performance characteristic.

[0008] Changing spring rate is more complex than changing damping. Coil springs require a physical adjustment and must often be unloaded to be adjusted or replaced in their entirety in order to effect the change in spring rate. The force exerted by an air spring as discussed above is determined by the pressure in the spring and the rate of said spring by the rate of change of said gas pressure within the chamber with excursion or displacement of the air spring. The internal volume or effective internal volume of an air spring effects rise in force as the spring compresses.

[0009] It is known to vary or tune the internal volumes and thus rates of air springs using a spacer or token, so that they can cope with different rider weights or loads. The spacer or token changes the available volume of gas being compressed when the spring is loaded. Sometimes, these spacers or tokens attach around a spindle cited beneath the air cap, or a piston is fitted on a ratchetted spindle so that it can be lowered into discreet positions, creating a variable height “ceiling” or volume to the air chamber. These systems usually require the air cap to be removed so that adjustments can be made, or connectable spacer tokens can be added or removed and then the spring be re-pressurised. Accordingly, such a system has similar challenges to adjustment as a coil spring with the need to unload and adjust the spring or carry heavy compressor components.

[0010] It is known that an adsorptive material filling a chamber causes that chamber to behave as if it has a larger volume than an empty chamber as described in WO2012052776.

[0011] An air spring has one difference over a conventional compression spring and that is by virtue of the volume of gas decreasing as the air spring compresses the rate of change of force with deflection increases as the spring compresses, whereas a standard coil spring has a constant spring rate. In normal operation this is not an issue as an air spring is designed to operate in the relatively linear region of the force deflection curve. However, when a large input is received, the air spring compresses far beyond the linear region and into a region with a much smaller gas volume and a rapidly increasing rate. This means at high compressions an air spring sees high forces very quickly. This can be advantageous, as the air spring does not run out of travel. However, it does mean that the force returning the air spring to equilibrium is high and can result in an aggressive bounce effect when returning from high deflections. This can make an air spring take longer to return to equilibrium from a large deflection than a conventional linear spring and with higher speed of travel which can be disadvantageous for vehicle handling and user comfort.

[0012] Summary of Invention

[0013] Aspects and / or embodiments seek to provide an adjustable rate air spring that can be adjusted whilst underload and without disassembly or removal from the vehicle.

[0014] According to a first aspect, there is provided an air spring comprising a pressurised, gaseous, springing medium contained within, a main chamber fluidly connected to each of one or more adjustment chambers at a sealable port, said main chamber including a load bearing surface arranged to transmit a force from a load in use to the springing medium, wherein said sealable port includes a sealing means for discreetly isolating the main chamber from each of the one or more adjustment chambers.

[0015] Preferably, one or more of the chambers and most preferably one or more of the adjustment chambers contain a mass of adsorptive material for increasing the effective volume thereof.

[0016] Optionally, the air spring may include two or more adjustment chambers.

[0017] Advantageously, said sealing port allows the main chamber to be selectively isolated from one or more of the adjustment chambers, allowing the spring rate to be controlled by changing the volume of gaseous springing medium in use by the spring and the effective volume available in which the gas is compressed. A plurality of chambers allows an increased number of adjustment options.

[0018] It will be understood by the skilled person, that the sealing port allows selective sealing of each of the one or more adjustment chambers and may include a sealing port for each of the one or more adjustment chambers for controlling fluid flow between said adjustment chamber and the main chamber. Additionally, the use of adsorptive material in the adjustment chambers increases the effective volume of said chambers, allowing them to be smaller in size. This is useful for applications where packaging volumes are small and where low weight is desirable.

[0019] Optionally, the air spring may further comprise an actuation means operatively connected to the sealing means and having an input located outside the chambers or controllable from outside of the chambers, for opening and closing the sealable port without disassembly of the air spring.

[0020] Advantageously, said actuation means allows manual or powered control of the sealable port, allowing the effective volume and thus the spring rate to be changed without disassembling the air spring or removing it from its installed position.

[0021] Optionally, the one or more adjustment chambers may include a first adjustment chamber having a first volume V1 and a second adjustment chamber having a second volume V2 wherein the first adjustment chamber has a greater volume V1 than the second adjustment chamber.

[0022] Optionally, the one or more adjustment chambers may include a first adjustment chamber having a first effective volume EV1 and a second adjustment chamber having a second effective volume EV2 wherein the first adjustment chamber has a greater effective volume than the second adjustment chamber.

[0023] Optionally, the first adjustment chamber may have an effective volume EV1 of between 150% and 300% of the effective volume EV2 of the second adjustment chamber and preferably an effective volume of 200% of the effective volume EV2 of the second adjustment chamber.

[0024] Optionally, the first adjustment chamber may contain adsorptive material and the second adjustment chamber does not, or all adjustment chambers may contain adsorptive material.

[0025] Advantageously, the use of two adjustment chambers containing adsorptive material with different effective volumes can allow four different spring rates to be achieved from only two chambers. When combined with sealing means under control of the actuation means, which provides control of the spring rate, this allows four discrete spring rates to be achieved and selected whilst the air spring is in use or without disassembly of the air spring. The difference between these four spring rates can be controlled by changing the volume of each of the adjustment chambers and / or the amount of adsorptive material therein, and thus the effective volume, of the adjustment chambers. This allows the configuration to be customisable based on the desire of the user or manufacturer.

[0026] Optionally, the sealing means may comprise a sealing face movable relative to the sealable port by rotation and / or translation from a first position, wherein no sealable port is closed to a second position where one or more of the sealable ports are closed for discretely varying the number of adjustment chambers connected to the main chamber.

[0027] Thereby, providing a plurality of discrete spring rates for the air spring.

[0028] Optionally, the air spring may further include a negative spring.

[0029] Optionally, said negative spring is a negative air spring comprising a negative spring chamber separate to and sealed from the main chamber and the load bearing surface has a first side exposed to the main chamber and a second side exposed to the negative air spring chamber and optionally the negative spring chamber contains adsorptive material.

[0030] The negative spring, reducing the stiction from the rest position of the spring causing behaviour closer to the desirable characteristics of a standard linear coil spring at low deflections.

[0031] Optionally, the air spring may have a cylindrical body having a central longitudinal axis A, and having a first end, a second end, and a central region therebetween, wherein the load bearing surface comprises a piston within the cylindrical body, connected to a shaft extending toward the first end, for applying a load to the piston, and wherein the one or more adjustment chambers extend axially within the second end and the second end is thereafter gas tight.

[0032] Optionally, the one or more adjustment chambers may extend axially from a radially and circumferentially extending closing wall to the second end, the closing wall having a central aperture and the sealable port comprising an axially extending cylindrical wall about the axis A, connected to the wall at said aperture to the main chamber and including one or more port apertures for discretely fluidly connecting each of the one or more adjustment chambers to the main chamber. Providing, suitable one or more suitable volume for adjustment chambers, in particular when there are a plurality of adjustment chambers within the restrictive packaging of a suspension component such as a fork or spring / shock absorber.

[0033] Optionally, the sealing face may be semi-cylindrical, located within the cylindrical wall for sealing thereto, and rotatable about the axis A from a first position o, wherein the one or more port apertures of the sealable port are open to a second position c where one or more of the port apertures of the sealable port are closed, isolating one or more of the one or more adjustment chambers from the main chamber.

[0034] The semi cylindrical sealing face and cylindrical wall, providing a strong seal that is assisted by the pressure in the main chamber when the air spring deflects whilst maintaining a strong mechanical advantage available within the packaging available in envisaged applications. In particular a suspension unit with a rotary adjuster, or when a powered actuator is moving the sealing means.

[0035] Optionally, the actuation means may be a manual or mechanical actuation means, such as by a switch or rotary dial connected to the sealing means. Providing the benefit of multiple spring rates with few components and low cost of production.

[0036] Optionally, the actuation means may include one or more electric, electromagnetic, hydraulic, or pneumatic powered actuators for moving the sealing means. Enabling remote or active control of the rate of the air spring whilst in use.

[0037] Optionally, the air spring may include a controller operatively connected to one or more of a position sensor, pressure sensor, or accelerometer, and the controller is operable to adjust the spring rate of the air spring in response to information from the one or more sensors.

[0038] Optionally, the controller is operable to cause the sealing means to connect one or more adjustment chambers to the main chamber at or near a point of high and / or peak deflection, high and / or peak pressure, and / or a change in direction of movement of the travel of the air spring.

[0039] Advantageously, using input data from the sensors described, the controller is able to change the spring rate in response to detected changes as described, and allowing stabilisation to be achieved faster after a large input to the air spring. Optionally, the air spring may further include an electronic user input device such as a section switch, smart ECU and / or personal electronic device operatively connected to the sealing means for control thereof.

[0040] Optionally, the opening and closing of connecting port by the sealing means by the controller is in response to external data such as GPS and / or mapping apps.

[0041] Optionally, the air spring may include a removable canister, wherein the removable canister includes the one or more adjustment chambers, the sealable port and preferably the actuation means.

[0042] According to a second aspect of the current invention, there is provided a removable canister for an air spring as described above. Thereby, providing adjustable spring rate to an existing suspension system. If the adjustment chambers contain adsorptive material, spring rates lower than that of the original spring can be added to existing air spring system.

[0043] According to a third aspect of the current invention, there is provided a bicycle, motor vehicle, or apparatus including isolation by means of suspension including an air spring as described above.

[0044] According to a fourth aspect of the current invention, there is provided a method of operating an air spring as described above, comprising receiving, at the controller, signals from the one or more sensors, the controller determining an appropriate spring rate in light of the signals from the one or more sensor, and the controller opening and closing the sealable port by the sealing means to provide said spring rate.

[0045] Optionally, the method of operating the air spring may further include determining, at the controller, a direction of travel of the loaded surface based on the signals from the one or more sensors, and the controller opening the sealable port during extension and closing the sealable port by the sealing means in compression.

[0046] Brief Description of Drawings

[0047] Embodiments will now be described, by way of example only and with reference to the accompanying drawings having like-reference numerals, in which: Figure 1 shows a bicycle suspension fork including an air spring (10) according to the current invention;

[0048] Figure 2 shows an air spring (10) according to the current invention;

[0049] Figure 3 shows an air spring (10) according to the current invention having the adjustment chambers as a removable canister;

[0050] Figure 4 shows a removable canister containing one or more spring adjustment chambers and a switchable sealing means;

[0051] Figure 5 shows a cross section of the internal structure of the removable canister of Figure 4;

[0052] Figures 6 to 9 show the possible spring rate adjustment options provided by an air spring fitted with two spring rate adjustment chambers of differing sizes; and

[0053] Figure 10 shows a graph of force against travel for an air spring having only a main compartment and an air spring having a plurality of spring rate adjustment chambers; and

[0054] Figure 11 shows a schematic view of the controller and connected devices or features.

[0055] Specific Description

[0056] Referring to Figure 1 , a first embodiment will now be described. Figure 1 shows a bicycle or motorcycle suspension fork 1 containing an air spring 10. One side of the forks is shown cut away to show a section view of the air spring 10. The air spring 10 contains a gaseous springing medium G and includes a main chamber 12, a load bearing surface 14 for transmitting load to the gaseous springing medium G, a negative spring 60 and one or more spring rate adjustment chambers 20 connected to the main chamber 12 at a sealable connection port 30. One side of the suspension forks 1 are cut away to show one air spring 10 but it will be understood that one or more air springs 10 can be included in a pair of suspension forks 1. One or more of the chambers 12, 20 include a mass of adsorptive material 40 for increasing the effective volume EV of that chamber. The air spring 10 is sealed and provides variable spring rate without use of a compressor to vary the pressure as required by known variable rate air spring systems. A bicycle fork is shown as an exemplary application of the current invention; however, the skilled person will understand that the claimed air spring can be used for any vehicle or system requiring suspension that benefits from a variable spring rate.

[0057] The sealable port 30 includes a sealing means 32 for discretely isolating the one or more adjustment chambers 20 from the main chamber 12 in order to vary the volume V of G to be compressed and volume available for G to move into when under pressure. The sealing means 32 may comprise a sealing face 34. The sealing face 34 is movable in a rotary or transalatory fashion for discretely isolating the one or more adjustment chambers 20 from the main chamber 12 at the sealable port 30. Figure 1 also shows the air spring 10 including an optional negative spring 60.

[0058] Increasing the volume V or effective volume EV of a chamber lowers the increase in force with deflection or rate of the air spring 10. An air spring can be large if a low rate is required. When varying the rate of an air spring by opening a chamber, in order to make a substantial change in rate, the one or more adjustment chambers 20 that are connectable to the main chamber 12 must be comparable in size to the main chamber in a ratio to the spring rate adjustment required. E.g. if a spring rate is to be halved the effective volume of the adjustment chamber 20 must be equal to the effective volume of the main chamber 12. Therefore, within a restricted packaging envelope such as that available in a suspension fork the smaller the chambers 12, 20 can be the lighter and smaller the fork can be. Introducing adsorptive material into the adjustment chambers allows a smaller adjustment chamber to have a greater effective volume and thus a greater effect on the rate of the air spring.

[0059] Figure 2 shows only the air spring 10. The air spring has a cylindrical body 70 having a first end 71 and a second end 72 and a mid-section 73 connecting the two ends. The cylindrical body 70 defines a central longitudinal axis A running the length of the body 70. The load bearing surface 14 is provided by a piston 74 running in and sealing to the mid-section 73 of the cylinder 70. The body 70 is sealed at the second end and the one or more adjustment chambers 20 extend longitudinally from the second end 72 to a radially and circumferentially extending wall 24. The main chamber is defined by the cylindrical body 70, the piston 14 and the wall 24. A shaft 76 is connected to the load bearing surface 14 for transmitting loads thereto. In this case the load bearing surface 14, namely the piston has a first face 16 toward the main chamber and a second face 18 facing away from the main chamber 12 to which the shaft 76 is attached. The shaft 76 extends from the piston 74 to the first end 71 for transmitting loads to the load bearing surface 16. One or more of the chambers 12, 20 include a mass of adsorptive material 40 therein. The sealable port 30 includes one or more port apertures 38 for each of the one or more adjustment chambers 20 allowing the sealing means 32 to discretely join one or more of the one or more adjustment chambers 20 to the main chamber 12 for allowing passage and or pressure of G therebetween or discretely isolate one or more of the adjustment chambers 20 from the main chamber 12 preventing the passage and / or pressure of G therebetween. In a preferred embodiment there are a plurality of adjustment chambers 20 forming segments of the cylindrical body 70 extending from the second end 72. The sealable port 30 includes a port aperture 38 for discretely connecting and disconnecting each of the plurality of adjustment chambers 20 to the main volume. In one embodiment the port apertures 38 may each be in the radially extending wall 24 and discretely closed by a sealing face 34 of the sealing means 32 when the sealing face 34 is rotated or translated.

[0060] The main chamber 12 is located between the piston 74 and the second end 72.

[0061] The sealing means 32 is controlled or driven by an actuation means 50. The actuation means 50 may be a mechanical actuator 52 such as a rotary knob 53 connected to the sealing means 32 by an actuation mechanism 56. The actuation mechanism 56 may be a shaft extending along axis A between the one or more adjustment chambers 20 to the sealing face 34.

[0062] The air spring in figure 2 also includes a negative spring 60 between the piston 74 and the first end of the damper housing. A negative spring 60 can be a resilient element such as a coil spring or an elastomer or it can be a gas spring.

[0063] Figure 3 shows a similar arrangement to the air spring 10 of figure 2. The air spring 10 figure 3 differs from the arrangement of figure 2 in that the air spring 10 includes a removable canister 80 at the second end 72 of the cylindrical body 70, the actuation means 50 comprises a powered actuator 54 and the negative spring 60 shown uses a gas springing medium.

[0064] The removable canister 70 includes at least the one or more adjustment chambers 20 and the sealable port 30 and preferably the actuation means 50. The canister 80 also includes a threaded portion 82 for threading into a complementary threaded portion 78 of the cylindrical housing 70. The canister 80 may also include an end cap 88 and a seal 84 for sealing the second end 72 of the cylindrical body 70.

[0065] The actuation means 50 comprises a powered actuator 54 such as an electromagnetic, electrical, hydraulic, or pneumatic, or other form of suitable powered actuator. The negative spring 60 includes a negative spring chamber 64 defined between the piston 74 and the first end 71 of the cylindrical body 70.

[0066] Figure 4 shows a removable canister 80 according to the current invention. Figure 5 shows a section taken at 90 degrees to axis A through the canister 80 to expose the structure of the adjustment chambers 20 and an alternative arrangement of the sealable port 30 compared to that shown in figure 2.

[0067] The radially and circumferentially extending wall 24 includes a central aperture 26 about the axis A. The sealable port 30 comprises a cylindrical wall 36 extending along axis A from the aperture 26 toward the end cap 88 and preferably to the end cap 88. The cylindrical wall 36 includes the port apertures 38 in this embodiment the port apertures 38 extend longitudinally along the cylindrical wall 36 in the direction of axis A. The sealing face 34 of the sealing means 32 is semi-cylindrical in shape or close there to meaning that at least along a portion of the length of the sealing face 34 half the circumference of the sealing face 34 is open. The sealing face 34 is sized to engage the cylindrical wall 36 in order to close the apertures 38 and prevent G flowing from the main chamber 12 to the one or more adjustment chambers 20. The port apertures 38 are arranged on a portion of the circumference of the cylindrical wall 36 equal or less than the portion of the radius through which the sealing face 34 extends for allowing the sealing face 34 to seal all the apertures 38 or none of the apertures 38. Thus, preferably the sealing face 34 extends through at or greater than 50% of the circumference of the cylinder and the apertures 38 are arranged on less than 50% of the circumference of the cylindrical wall 36. The skilled person will understand that this arrangement is a preferable arrangement and that multiple apertures in the sealing face 34, that extends through the full circumference could provide a solution within the scope of the current invention, with apertures 38 arranged over more than 50% of the circumference of the cylindrical wall 36 if they are

[0068] It will be understood that the adjustment chambers 20 are gas tight apart from the sealable port 30 which may be opened or closed by the sealing means 32. When closed by the sealing means 32 the port 30 allows little or no gas flow. The radially and circumferentially extending wall 24 is connected to and / or sealed to the cylindrical body 70 in the embodiment of figure 2 without a removable canister 80. The removable canister includes an axially and circumferentially extending outer wall 86 connected to and / or sealed to the radially extending wall 24 and the cap 88 to form the gas tight one or more adjustment chambers 20. It can be seen in figures 4 and 5 that a preferable arrangement including two adjustment chambers 20 is shown. The plurality of adjustment chambers 20 are sealed from one another, arranged in segments, and separated by a plurality of radially and axially extending dividing walls 28. Specifically, a first adjustment chamber 21 and a second adjustment chamber 22 is included in the embodiment shown in figure 5. The chambers 20 shown are of differing volume but the skilled person will understand that the two chambers 20 may have the same volume.

[0069] The first adjustment chamber 21 has a volume V1 and an effective volume EV1 and the second adjustment chamber 22 has a volume V2 and an effective volume EV2. If no adsorptive material is included in either chamber, then V1=EV1 and V2=EV2. However, if adsorptive material is included in the first adjustment chamber 21 V1<EV1 , if adsorptive material is included in the second adjustment chamber 22 V2<EV2.

[0070] In a preferred embodiment the first adjustment chamber 21 is greater in volume and / or effective volume than the second adjustment chamber 22. Thereby, providing a greater range of adjustment options for spring rate. Ideally the volume or effective volume V1 of the first adjustment chamber 21 is between 150% and 500% of the effective volume V2 of the second adjustment chamber 22. Advantageously, as shown in figures 6 to 9, this provides 4 different rates for the air spring 10 from only two adjustment chambers 20. Most preferably, the volume V1 or effective volume EV1 of the first adjustment chamber 21 is at or around 200% of the volume V2 or effective volume EV2 of the second adjustment chamber 22. Further advantageously providing 4 evenly stepped changes in volume of the air spring 10 and thus correspondingly four similar and thus predictable changes in spring rate. This may not be desirable, and the manufacturer or user may wish to have the option of a small change at each end of a big step in the range of adjustment in which case an effective volume of EV1 that is very much greater than the effective volume EV2 may be preferable.

[0071] Note that it is possible to achieve EV1>EV2 using a first adjustment chamber 21 that has the same volume V1 as the volume V2 as the second adjustment chamber 22 through the inclusion of adsorptive material in the first adjustment chamber 21.

[0072] The effective volume of an air spring cavity containing adsorptive material is defined as the equivalent volume of a chamber containing only air or gas that achieves the same spring rate behaviour, or rate of change of pressure with volume changes as the cavity containing adsorptive material at a given temperature and pressure. Effective volume can be expressed as a factor or percentage of absolute volume or an effective value. For example, at 5 bar and 20C, a cavity containing a particular grade of adsorptive material will behave dynamically as if it has 201 % the volume of a cavity filled with air alone. Thus, if the cavity is 1000cc, the cavity will have an effective volume of 201 Occ.

[0073] It will be understood that this aspect of the invention is equally applicable without including adsorptive material in any of the adjustment chambers.

[0074] Whilst two adjustment chambers are shown it will be understood that it may be beneficial to have greater than two adjustment chambers in order to provide an even broader range of adjustment options within the scope of this invention.

[0075] Figures 6 to 9 show four different settings providing four different rates for a preferred embodiment of the air spring 10 of the current invention. Said figures show a cross section through an air spring 10 having two adjustment chambers 20 having a sealable port 30 comprising a cylindrical wall 36, with an aperture 38 into each of the two adjustment chambers 20 and a sealing means 32 having a semi-cylindrical sealing face 34. The first adjustment chamber 21 is greater in volume or effective volume than the second adjustment chamber 22. Indeed, the numerals under the figures denote the amount of total volume of the adjustment chambers 20 that is connected to the main chamber 12. Thus, it can be seen that the first adjustment chamber 21 is double the size of the second adjustment chamber 22. The first adjustment chamber 21 in figure 7 provides 2 / 3 of the available volume and in figure 8 the second adjustment chamber 22 provides 1 / 3.

[0076] In figure 6 the sealing face 34 is rotated such that the aperture 38 between the main chamber 12 and the first adjustment chamber 21 is open and the aperture 38 between the main chamber 12 and the second adjustment chamber 22 is open. This configuration providing the maximum available volume in which G can work and correspondingly the lowest spring rate. Figure 7 shows only the aperture 38 between the main chamber 12 and the first adjustment chamber 21 is open. This provides the second greatest volume as the first adjustment chamber 21 is 2 / 3 of the volume in the two adjustment chambers in which G may work and thus the next stiffest rate. Figure 8 shows only the aperture 38 between the main chamber 12 and the second adjustment chamber 22 is open. The second adjustment chamber 22 is a lower volume than the first adjustment chamber 21 , therefore, the volume is reduced again, and the spring rate is increased. Finally in figure 9 all apertures 38 are closed and no gas G can pass between the main chamber and the adjustment chambers 20 providing the lowest volume of G and therefore the highest spring rate. Figure 7 shows a graph of the effect of introducing an adjustment chamber the dashed line shows the effect of placing a volume reducing spacer in the main volume. The solid line shows only a simple main volume, and the dotted line shows the effect of two adjustment volumes open to the main chamber including adsorbent material 40 in each of the adjustment volumes.

[0077] Adsorbent material 40 can be included in the main chamber 12 and / or either or all of the adjustment chambers 20. The benefit of including adsorbent material in the adjustment chambers 20 is that the effective volume provided when each of the chambers 20 is opened is greater than if there was no adsorbent material 40 therein. Therefore, it is possible to fit a canister 80 including one or more adjustment volumes 20 that contain adsorbent material 40 to an existing air spring system not according to the current invention and create an adjustable range that extends below that of the original spring despite introducing the canister into and thus reducing the remaining volume of the main chamber 12. For the avoidance of doubt the canister 80 as shown in figure 4 and figure 5 alone is an embodiment of the current invention. The canister 80 provides the advantages associated with the air spring 10 to any existing system.

[0078] The air spring 10 may further include a controller 100, for controlling the sealing means 32 and thus the opening and closing of the sealable port 30. For the controller 100 to be effective the actuation must be by powered actuators 54 to which the controller 100 is operatively connected. These may include electric, electromagnetic, hydraulic, pneumatic actuators or any other suitable powered actuator.

[0079] In order to determine the position or setting of the sealing means 32 and thus the spring rate provided by the controller 100, the controller 100 is configured to receive signals or information from internal and / or external sources. The controller 100 may be operatively connected to one or more sensors 101 such as a position sensor 102, a pressure sensor 104, an accelerometer 106 or any other sensor that can provide information on the state of the air spring 10 or surroundings thereof. The controller 100 may also receive information or signals from an external device such as a user remote control 112 or a user's personal electronic device 114 such as a smart phone.

[0080] External devices 110 may only provide instructions for settings for the sealing means 32 that are carried out by the controller 100 or external devices may provide the controller 100 with information such as GPS location or terrain information. The user remote control 112 may be a handlebar remote control which replicates the aforementioned rotary knob 53 in a remove fashion. The external device 110 may be a more complex device such as a smart phone 114 including an app for processing data. The controller 100 may provide information to the external device 110. Accordingly, the controller 100 may include a receiver 107 or transceiver 108 as appropriate.

[0081] The controller 100 may receive signals from the one or more sensors 101 for determining one or more states of the air spring 10 including pressure, position, movement, or rate of change of movement or any other information about the air spring 10 that may aid the controller 100 or external device 110 in determining a setting for the air spring 10.

[0082] In a preferred embodiment the controller 100 receives signals from the one or more sensors 101 and determines in response to those signals a setting for the air spring 10. The controller 100 causes the actuation means 50 to move the sealing means 32 to open or close the sealable port 30 in order to provide the determined setting for the air spring 10.

[0083] The controller 100 may, in particular, be configured to determine a large and / or rapid compression of the air spring 10 and the maximum point of this input. This may be through receiving a peak pressure or high pressure from the pressure sensor 104, a high rate of change, high deflection and / or inflection from the position sensor 102, or a high acceleration in a particular direction from the accelerometer 106. The controller 100 may then determine that the maximum deflection has been reached and in response cause the actuation means 50 to move the sealing means 32 to connect one or more adjustment chambers 20 to the main chamber 12 in order to lower the force of the air spring on the return or extension after the big deflection or compression. Thereby causing the air spring 10 to settle to a normal position with fewer cycles without the requirement for excessive damping that would otherwise compromise normal operation of the air spring 10. The controller 100 may thereafter determine based on information or input from the sensors 101 that the air spring 10 has returned to a baseline position or has changed direction into compression once more and cause the actuation means 50 to move the sealing means 32 to isolate or disconnect one or more of the one or more adjustment chambers 20 from the main chamber 12 to increase the rate of the air spring 10 in preparation for the next compression or high load event. adsorptive material is preferably activated carbon but may also be a Metal Organic Framework MOF, zeolite or other adsorbent material.

[0084] Whilst an air spring is claimed it will be understood the gaseous springing medium can be pure nitrogen, air, or another compressible gas within the scope of the claimed invention. Any system feature as described herein may also be provided as a method feature, and vice versa. As used herein, means plus function features may be expressed alternatively in terms of their corresponding structure. Any feature in one aspect may be applied to other aspects, in any appropriate combination. In particular, method aspects may be applied to system aspects, and vice versa. Furthermore, any, some and / or all features in one aspect can be applied to any, some and / or all features in any other aspect, in any appropriate combination. It should also be appreciated that particular combinations of the various features described and defined in any aspects can be implemented and / or supplied and / or used independently.

Claims

CLAIMS:1 . An air spring (10) comprising: a pressurised, gaseous, springing medium (G) contained within; a main chamber (12), fluidly connected to each of, two or more adjustment chambers (20), at a sealable port (30); the main chamber (12) including a load bearing surface (14), arranged to transmit a force (F) from a load, in use to the springing medium G; wherein the sealable port (30) includes a sealing means (32) for discreetly isolating the main chamber (12) from each of the two or more adjustment chambers (20) and one or more of the adjustment chambers (20) contain a mass of adsorptive material (40) for increasing the effective volume thereof.

2. An air spring (10) according to claim 1 further comprising an actuation means (50) operatively connected to the sealing means (32) located outside the chambers (12, 20) for opening and closing the sealable port (30) without disassembly of the air spring (10).

3. An air spring (10) according to any preceding claim wherein the two or more adjustment chambers (20) include a first adjustment chamber (21) having a first volume V1 and a second adjustment chamber (22) having a second volume V2 wherein the first adjustment chamber (21) has a greater volume V1 than the second adjustment chamber (22).

4. An air spring (10) according to claim 1 or claim 2 wherein the two or more adjustment chambers (20) include a first adjustment chamber (21) having a first effective volume EV1 and a second adjustment chamber (22) having a second effective volume EV2 wherein the first adjustment chamber (21) has a greater effective volume than the second adjustment chamber (22).

5. An air spring (10) according to claim 4 wherein the first adjustment chamber (21) has an effective volume EV1 of between 150% and 300% of the effective volume EV2 of the second adjustment chamber (22) and preferably an effective volume of 200% of the effective volume EV2 of the second adjustment chamber (22).

6. An air spring (10) according to any one of claims 3 to 5 wherein the first adjustment chamber (21) contains adsorptive material, and the second adjustment chamber (22) does not, or wherein all adjustment chambers (20) contain adsorptive material.

7. An air spring (10) according to any preceding claim wherein the sealing means (32) comprises a sealing face (34) movable relative to the sealable port (30) by rotation and / or translation from a first position (34o) wherein no sealable port (30) is closed to a second position (34c) where one or more of the sealable ports (30) are closed for discretely varying the number of adjustment chambers (20) connected to the main chamber (12).

8. An air spring (10) according to any preceding claim further including a negative spring (60).

9. An air spring (10) according to claim 8 wherein the negative spring (60) is a negative air spring (62) comprising a negative spring chamber (64) separate to and sealed from the main chamber (12) and the load bearing surface (14) has a first side (16) exposed to the main chamber (12) and a second side (18) exposed to the negative air spring chamber (64) and optionally the negative spring chamber (64) contains adsorptive material (40).

10. An air spring (10) according to any preceding claim comprising a cylindrical body (70) having a central longitudinal axis A, and having a first end (71), a second end (72) and a central region (73) therebetween; wherein the load bearing surface (14) comprises a piston (74) within the cylindrical body, connected to a shaft (76) extending toward the first end (71), for applying a load to the piston (74); wherein the two or more adjustment chambers (20) extend axially within the second end (72) and the second end (72) is thereafter gas tight.

11. An air spring (10) according to claim 10 wherein the two or more adjustment chambers (20) extend axially from a radially and circumferentially extending closing wall (24) to the second end (72), the closing wall (24) having a central aperture (26) and the sealable port (30) comprises an axially extending cylindrical wall (36) about the axis A, connected to the closing wall (24) at said aperture (26) to the main chamber (12) and including one or more port apertures (38) for discretely fluidly connecting each of the two or more adjustment chambers (20) to the main chamber (12).

12. An air spring (10) according to claim 11 wherein the sealing face (34) is semi- cylindrical, located within the cylindrical wall (36) for sealing thereto, and rotatable about the axis A from a first position (30o) wherein the one or more port apertures (38) of the sealable port (30) are open to a second position (30c) where one or more of the port apertures (38) of the sealable port (30) are closed, isolating one or more of the two or more adjustment chambers (20) from the main chamber (12).

13. An air spring (10) according to any one of claims 3 to 12 when dependent on claim 2 wherein the actuation means (50) is a manual or mechanical actuation means (52) such as by a switch or rotary dial connected to the sealing means (32).

14. An air spring (10) according to any one of claims 3 to 12 when dependent on claim 2 wherein the actuation means (50) includes one or more electric, electromagnetic, hydraulic, or pneumatic powered actuators (54) for moving the sealing means (32).

15. An air spring (10) according to claim 14 wherein the air spring (10) includes a controller (100) operatively connected to one or more of a position sensor (102), pressure sensor (104) or accelerometer (106) and the controller (100) is operable to adjust the spring rate of the air spring (10) in response to information from the one or more sensors.16 An air spring (10) according to claim 15 wherein the controller is operable to cause the sealing means (32) to connect one or more adjustment chambers (20) to the main chamber (12) at or near a point of high and / or peak deflection, high and / or peak pressure and / or a change in direction of movement of the travel of the air spring (10).

17. An air spring (10) according to any preceding claim furthering including an electronic user input device (110) such as a section switch, smart ECU and / or personal electronic device operatively connected to the sealing means (32) for control thereof.

18. An air spring (10) according to any one of claims 14 to 17 wherein the opening and closing of connecting port (30) by the sealing means (32) by the controller (100) is in response to external data such as GPS and / or mapping apps.

19. An air spring (10) according to any preceding claim including a removable canister (80), wherein the removable canister (80) includes the two or more adjustment chambers (20), the sealable port (30) and preferably the sealing means (32).

20. A removable canister (80) for an air spring (10) as claimed in claim 19.

21. A bicycle (200), motor vehicle (202), or apparatus including isolation by means of suspension (204) including the air spring (10) of claims 1-18.

22. A method of operating the air spring (10) of claims 14 to 15 comprising: receiving at the controller (100), signals from the one or more sensors (101 , 102, 103); the controller (100) determining an appropriate spring rate in light of the signals from the one or more sensors (101 , 102, 103); and the controller (100) opening and closing of the sealable port (30) by the sealing means(32) to provide said spring rate.

23. The method of operating the air spring (10) according to claim 22 further including determining at the controller (100) a direction of travel of the loaded surface (14) based on the signals from the one or more sensors (101 , 102, 103) and the controller (100) opening the sealable port (30) during extension and closing the sealable port (30) by the sealing means (32) in compression.

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