Rotationally balanced smart ball

Abstract

An inflatable ball comprises a bladder having a bladder wall defining an inflatable interior of the ball. At least one device is mounted on or over the bladder wall such that a centre of mass of the at least one device is located away from a centre of the inflatable interior of the ball. The at least one device includes at least one electronic device. The centre of mass of the at least one device defines a first point on the bladder wall coincident with or closest to the centre of mass of the at least one device and a second point on the bladder wall opposite the first point. The ball comprises a distributed balancing mass for at least partially rotationally balancing the mass of the at least one device. The distributed balancing mass comprises one or more balancing mass elements on or over the bladder wall. The one or more balancing mass elements are arranged at a plurality of locations spaced around the second point on the bladder wall and closer to the second point than the first point. One of the one or more balancing mass elements comprises a valve of the inflatable ball and / or wherein one of the one or more balancing mass elements is attached on or over the bladder wall and comprises a plurality of sub-masses that are interconnected by one or more interconnecting portions, such that the plurality of sub-masses may move relative to one another during deformation of the bladder wall by stretching or bending of the interconnecting portions.

Description

[0001] ROTATIONALLY BALANCED SMART BALL

[0002] FIELD OF THE INVENTION

[0003] The invention relates to inflatable balls, particularly sports balls, containing electronic devices and to techniques for balancing the additional mass introduced by the electronic devices.

[0004] BACKGROUND

[0005] Data collection and usage has become a vital part of modern-day sports and are only likely to increase in importance. Data collection in sports is beneficial for many reasons. Firstly, data collection is valuable for training, as it allows the athletes to gain a better knowledge of their performance and key statistics. For example, the total distance covered in a match by a certain player may be a useful indicator of their fitness and level of participation. Secondly, statistics and data figures have become an increasingly important aspect of the viewer experience during sporting events.

[0006] Increasingly, sensors and trackers are being incorporated into sports balls. Such ball devices allow spectators to see statistics such as speed, distance, number of passes, or the force exerted by an athlete during kicking, for example. There are two main ways of introducing electronics into the ball. A first involves mounting the electronics near the centre of the ball, which keeps the ball rotationally balanced. This technique has the problem that it can be difficult to manufacture an inflatable sports ball in which an electronic device is suspended in the centre of the ball. It also makes it practically impossible to access the electronic device after manufacture. A second option is to mount the electronics on the periphery of the ball. The electronics can either be mounted to the inside surface of the bladder or dropped into a recess in the bladder from the outside of the sports ball, for example. Balls constructed in line with this technique are generally easier to manufacture and may allow more convenient access to the electronic device for maintenance and charging. However, this option has the downside that it tends to unbalance the ball.It is known to offset the mass of an electronic device mounted on the periphery of the sports ball by placing a balancing mass opposite to the electronic device. However, this solution has the problem that it introduces a preferred rotation axis of the ball or otherwise changes the way the ball rotates about other axes. It is desirable to devise a means of rotationally balancing a sports ball that does not suffer from this problem.

[0007] There is also an additional problem that, whenever a discrete balancing mass is introduced into a sports ball, this can affect both the shape of the ball and the way the ball bounces. It is desirable to minimise the affect of any balancing arrangement on these behaviours of the ball.

[0008] SUMMARY OF INVENTION

[0009] In accordance with a first aspect of the invention, there is provided an inflatable ball comprising: a bladder having a bladder wall defining an inflatable interior of the ball; at least one device mounted on or over the bladder wall such that a centre of mass of the at least one device is located away from a centre of the inflatable interior of the ball, the at least one device including at least one electronic device, the centre of mass of the at least one device defining a first point on the bladder wall coincident with or closest to the centre of mass of the at least one device and a second point on the bladder wall opposite the first point; and a distributed balancing mass for at least partially rotationally balancing the mass of the at least one device, the distributed balancing mass comprising one or more balancing mass elements on or over the bladder wall, the one or more balancing mass elements being arranged at a plurality of locations spaced around the second point on the bladder wall and closer to the second point than the first point, wherein one of the one or more balancing mass elements comprises a valve of the inflatable ball and / or one of the one or more balancing mass elements is attached on or over the bladder wall and comprises a plurality of sub-masses that are interconnected by one or more interconnecting portions, such that the plurality of sub-masses may move relative to one another during deformation of the bladder wall by stretching or bending of the interconnecting portions. Preferably, each balancing mass element either comprises the valve, or comprises a plurality of sub-massesthat are interconnected by one or more interconnecting portions, such that the plurality of sub-masses may move relative to one another during deformation of the bladder wall by stretching or bending of the interconnecting portions

[0010] In order to balance the mass of an electronic device mounted at or near the periphery of the sports ball, it is advantageous not to simply provide a balancing mass opposite the device (the second point), but to space the balancing mass at a series of locations around this opposite point. Since the valve is part of the balancing mass, and the balancing mass is closer to the second point than it is to the first point, this will achieve the effect of moving the centre of mass substantially to the centre of the ball, so that the balancing mass does not have a noticeable effect on different rotation axes of the ball. Furthermore, when the one or more balancing mass elements comprises a valve of the inflatable ball the additional weight required to rotationally balance the ball is reduced as the valves weight can be used, rather than having to provide an additional mass. Further still, athletes will be used to the way the valve impacts the shape of the ball and the way it bounces, such that the valve may be used to balance the ball without introducing any difference in the way the ball behaves.

[0011] The use of sub-masses for the one or more balancing mass elements results in avoidance of the one or more balancing mass elements distorting the overall shape of the bladder. This is because, if the one or more balancing mass elements are comprised of a single block or section of material, then this will result in a local change of shape in the inflatable ball once inflated, therefore creating a departure from the overall intended shape of the ball. The sub-masses address this issue by being able to move and bend relative to one another, thereby allowing the one or more balancing mass elements to stretch and bend in a more natural way that allows the ball to maintain its overall intended shape once inflated.

[0012] Furthermore, it allows the ball to behave more normally when bounced or kicked as the coefficient of restitution of the ball is impacted less by sub-masses than a single large mass. This is because the sub-masses present much less resistance to deformation as they are able to bend, flex, and generally deform relative to one another.The sub-masses do not need to be added to the inside of the bladder, as they could also be added to the outside of the bladder, or to the inside panels which surround the bladder.

[0013] Therefore, the provision of sub-masses allows one or more balancing mass elements which are more compliant, thereby improving the sphericity and coefficient of restitution of the ball while still providing a rotationally balanced inflatable ball comprising electronics.

[0014] In some examples, the valve may account for all the mass of one of the balancing mass elements at its respective location. In this situation, where the one or more balancing mass elements consist of a valve, the additional weight required to rotationally balance the ball is significantly reduced as the valve weight can be used, rather than having to provide an additional mass.

[0015] In other examples, the valve may account for part of the mass of one of the balancing mass elements at its respective location. In this case, the balancing mass comprising the valve preferably further comprises an additional mass element. In some examples, the additional mass element may comprise a block of rubber. In this situation, where the one or more balancing mass elements comprise a valve and an additional mass element, the additional weight required to rotationally balance the ball is reduced as the valves weight can be used, rather than having to provide an additional mass.

[0016] It can be understood that any suitable material may be used, such as latex, butyl rubber, synthetic rubber, TPU, PVC, polyurethane or any combination of these materials (this is not an exhaustive list). Generally, any material which is capable of attachment to the bladder wall may be used.

[0017] Preferably, when one of the one or more balancing mass elements comprises the plurality of sub-masses, one or more of the plurality of sub-masses are arranged in a regular or irregular two-dimensional distribution of sub-masses, such that the plurality of sub-masses may move relative to one another along each of at least two substantially orthogonal directions during deformation of the bladder wall bystretching or bending of the interconnecting portions. The two directions here refer to two directions along bladder wall.

[0018] It will be appreciated that, since the plurality of sub-masses may move relative to one another along at least two substantially orthogonal directions, this also means that the sub-masses can move relative to one another in a diagonal direction which comprises components in the direction of the at least two substantially orthogonal directions.

[0019] Furthermore, it can be appreciated that the plurality of sub-masses may move relative to one another along at least three substantially orthogonal directions. In other words, they move along any of two orthogonal directions in parallel with the bladder wall as well as in an orthogonal direction perpendicular to the bladder wall. It should also be noted that the sub-masses may move relative to one another in any direction which comprises one or more components of any of the at least three orthogonal directions. In other words, the sub-masses can move relative to one another in a three-dimensional diagonal direction, as well as purely along only one direction.

[0020] This is beneficial as it allows for the bending and moving of the sub-masses in at least two dimensions, preferably at least three dimensions, and not only in one direction. This allows for a greater ability of the bladder to maintain its intended shape as the mass can bend and flex to a greater degree along the plane which is being expanded.

[0021] In an implementation where the sub-masses are arranged in a regular or irregular two-dimensional distribution of sub-masses, it is preferable that of the plurality of sub-masses are square, rectangular, circular, triangular, or oval in a cross-section parallel to the interconnecting portions. Furthermore, it is preferable that the one or more of the plurality of sub-masses have a constant cross-section in a direction perpendicular to the interconnecting portions. This is beneficial as it allows for the sub-masses to be easily manufactured out of a single block of material using reductive manufacturing methods. Alternatively, the one or more of the plurality of sub-masses have a non-constant cross-section in a direction perpendicular to theinterconnecting portions. This is beneficial as sub-masses with a cross-section which reduces in a direction away from where it is attached to the bladder wall allows for greater relative movement of sub-masses as they are less likely to interfere with one another by coming in contact.

[0022] Preferably, when one of the one or more balancing mass elements comprises the plurality of sub-masses, the balancing mass element comprising the plurality of sub-masses is attached on or over the bladder wall using an adhesive or welding.

[0023] Preferably, when one of the one or more balancing mass elements comprises the plurality of sub-masses, the interconnecting portions are part of a base of the balancing mass element, the balancing mass element being attached on or over the bladder wall via the base

[0024] This is beneficial as it allows for the sub-masses to all be interconnected while also providing an easy and effective means of securely attaching the mass to the bladder wall.

[0025] Preferably, when one of the one or more balancing mass elements comprises the plurality of sub-masses, the sub-masses and the interconnecting portions are formed of rubber. It can be understood that any suitable material may be used, such as latex, butyl rubber, synthetic rubber, TPU, PVC, polyurethane or any combination of these materials (this is not an exhaustive list).

[0026] Preferably, when one of the one or more balancing mass elements comprises the plurality of sub-masses, wherein the sub-masses and the interconnecting portions are integrally formed.

[0027] This is beneficial as it simplifies the manufacture of the balancing mass element as the entire structure is formed together, and also provides greater security in that the sub-masses are less likely to become unattached from one another and the interconnecting portions.

[0028] Preferably, when one of the one or more balancing mass elements comprises a plurality of sub-masses, the interconnecting portions are formed of a materialhaving a Young’s modulus not more than 50%, or 20%, or 10%, higher than the Young’s modulus of the material forming the bladder wall, preferably equal to or lower than the Young’s modulus of the material forming the bladder wall.

[0029] This is beneficial as it aids in the ability of the interconnecting portions to bend and flex with the bladder wall when the bladder itself is changing in shape. This is because the interconnecting portions are not overly stiff and inflexible and are therefore able to sufficiently deform to allow the ball to maintain its desired shape.

[0030] Similarly, the plurality of sub-masses results in a balancing mass element with a reduced area moment of inertia, relative to a singular solid balancing mass element with the same outer dimensions, which in turns allows for a greater change in shape (namely, curvature) of the balancing mass element for the same applied force. The area moment of inertia is reduced as the interconnecting portions provide a reduced cross-sectional area portion in the balancing mass element which in turn results in overall reduced cross-sectional area.

[0031] Therefore, even if the intrinsic properties of the balancing mass element remain unchanged (such as Young’s modulus), the provision of the plurality of submasses structure results in a balancing mass element with greater flexibility and ability to bend to the required shape when the ball is inflated. In other words, the plurality of sub-masses resist the bending of the inflated ball less than a balancing mass element comprised of a single block, or other such uniformly shaped, mass.

[0032] For example, a balancing mass element formed of a block of material which has been scored, such that a plurality of sub-masses are formed with interconnecting portions, will have a reduced area moment of inertia compared to the unscored block of material (even though the Young’s modulus remains unchanged). Thus, the scored block resists the required change in shape to a lesser amount than the unscoured block.

[0033] Preferably, the bladder wall is between 0.0001 m and 0.01 m thick when the bladder is in an uninflated state.Preferably, when one of the one or more balancing mass elements comprises a plurality of sub-masses, the or each balancing mass element comprises 4 or more sub-masses, or 8 or more sub-masses, or preferably 16 or more sub-masses.

[0034] This is beneficial as the greater the number of sub-masses the greater the achievable flexibility and ease of forming of a desired shape for the bladder.

[0035] Preferably, when one of the one or more balancing mass elements comprises a plurality of sub-masses, the largest dimension of the balancing mass element is no more than 0.1 m, and preferably no more than 0.05 m.

[0036] Preferably, when one of the one or more balancing mass elements comprises a plurality of sub-masses, the interconnected portions are no more than 0.005 m thick, and preferably no more than 0.0025 m thick, and most preferably no more than 0.001 m thick. The thickness is measured in a direction perpendicular to the bladder wall. Where thickness are disclosed elsewhere, they too are in a direction measured perpendicular to the bladder wall.

[0037] The interconnected portion comprising a relatively thin thickness allows for it to bend and move as is required, and does not overly thicken and stiffen the bladder wall it is attached too.

[0038] It can be appreciated that the interconnecting portions have a substantially smaller cross-section relative to the sub-masses in a direction perpendicular to the bladder wall, such that the force required to bend the balancing mass element is reduced. Preferably, the cross-sectional area of the interconnecting portion in a direction perpendicular to the bladder wall is no more than half of the cross-sectional area of the sub-mass in a direction perpendicular to the bladder wall. Even more preferably, the cross-sectional area of the interconnecting portion in a direction perpendicular to the bladder wall is no more than a quarter of the cross-sectional area of the sub-mass in a direction perpendicular to the bladder wall. Most preferably, the cross-sectional area of the interconnecting portion in a direction perpendicular to the bladder wall is no more than one-tenth of the cross-sectional area of the sub-mass in a direction perpendicular to the bladder wall.Due to the thinness of the interconnecting portions, due to the stress imparted on them during inflation, they may tear or otherwise separate from the sub-masses they connect. It may be preferable to score or otherwise weaken a portion of the interconnecting portions such that they tear or separate more easily during inflation.

[0039] The tearing or separation of the interconnecting portions from the sub-masses they connect can be beneficial as it will allow the sub-masses to move more independently of one another, thereby resulting in reduced resistance to changes in the balder shape.

[0040] Therefore, preferably, the interconnecting portions are configured such that some, or all, of the interconnecting portions separate (or tear) during the inflation of the inflatable ball. It can be understood that the inflation of the inflatable ball is to the amount of inflation typical and expected for the ball when the ball is in use.

[0041] In some cases, tearing or separation of the interconnecting portions may provide an array of separate balancing mass elements, each independently attached on or over the bladder wall, wherein each array of separate balancing mass elements is substantially evenly distributed by mass with respect to a respective balancing point, as discussed herein.

[0042] Preferably, when one of the one or more balancing mass elements comprises a plurality of sub-masses, the surface of the balancing mass element which attaches to the bladder has a surface area no greater than 0.01 m2, preferably no greater than 0.0025 m2.

[0043] Preferably, the centre of mass of a sub-mass is no more than 0.01 m away from the centre of mass of its closest sub-mass. Even more preferably, the centre of mass of a sub-mass is no more than 0.005 m away from the centre of mass of its closest sub-mass.

[0044] Preferably, the one or more balancing mass elements comprises one or more balancing mass elements arranged substantially at or substantially evenly distributed by mass with respect to each of at least three balancing points spacedaround the second point, the three balancing points together with the first point and / or the centre of mass of the of the at least one device defining four vertices of a tetrahedron, preferably a substantially regular tetrahedron.

[0045] The distributed balancing mass may comprise one of: a) at least four balancing mass elements one of which is the valve or the plurality of sub-masses, the balancing mass elements being arranged substantially at or substantially evenly distributed by mass with respect to each of at least four balancing points equally spaced around the second point and closer to the second point than the first point; or b) one or more mass balancing elements arranged on or over the bladder wall along one or more tracks along the bladder wall defining substantially all or one or more parts of the circumference of a circle or an ellipse.

[0046] In order to balance the mass of an electronic device mounted at or near the periphery of the sports ball, it is advantageous not to simply provide a balancing mass opposite the device (the second point), but to space the balancing mass at a series of locations around this opposite point. Since the balancing mass is closer to the second point than it is to the first point, it will still achieve the effect of moving the centre of mass closer to the centre of the ball, but does this while reducing the effect the balancing mass will have on different rotation axes of the ball.

[0047] Preferably, the device comprises: an electronics casing attached to, or integrally formed with, the bladder, the electronics casing defining a compartment adjacent an inner surface of the inflatable interior of the ball and sealed within the inflatable interior of the ball; wherein the at least one electronic device is located within the compartment of the electronics casing; and wherein the electronics casing comprises one or more perforations through the electronics casing so that the compartment of the casing is in fluid communication with the inflatable interior of the ball.

[0048] As used in this application, the compartment being in fluid communication with the inflatable interior of the ball means that fluids can substantially freely move from the inflatable interior to the compartment so that, substantially instantaneouslyafter inflation of the ball, the compartment and inflatable interior are at the same pressure. Fluid in this application has its usual definition, that of a material which continuously deforms under an applied shear stress / external force. An example of a fluid would be water or air. As will be understood, most implementations of the inflatable ball will use air or other common gasses as the fluid, however the invention is not limited to this.

[0049] As the compartment and inflatable interior of the ball are in fluid communication, air, for example, is able to move between the two without significant resistance, allowing the air pressure to equalise in either component if one is inflated or deflated.

[0050] Advantageously, by allowing the compartment to be in fluid communication with the inflatable interior of the ball it prevents the high pressure inside of the inflatable interior of the ball from pressing against the electronics in the compartment and deforming the compartment or urging the electronics out of the compartment. Therefore, damage or impedance in the ability of the at least one electronic component to function properly is minimised or eliminated.

[0051] As well as this, by having the compartment and inflatable interior of the ball at the same pressure, it reduces any bulging, or other such deformity, to the outside of the inflatable ball from any electronics casing, or component, being pressed against the bladder, or any outer layer, due to a pressure differential. Therefore, the inflatable ball can maintain its desired shape and characteristics. This is particularly important in line with the aim of maintaining the shape and bouncing behaviour of the ball. By maintaining shape in this way, it is not necessary to provide the electronics casing with heavy rigid materials to maintain the shape of the ball against the pressure inside interior of the bladder. Such heavy materials would require increasing the masses of the distributed balancing masses, leading to an overall heavier ball. Therefore, the ability of this arrangement to maintain shape without structural reinforcement is important to keeping the overall weight of the balanced ball low.Furthermore, having the compartment and inflatable interior of the ball at the same pressure allows the at least one electrical component to measure the pressure of the inflatable interior of the ball if required.

[0052] It may be desirable to have a plurality of perforations through the electronics casing, as this also contributes to lightweighting of the electronics casing. In a ball balanced by a tetrahedral arrangement, for example, every unit of mass removed from the device results in a fourfold reduction in the mass of the balanced ball. Therefore, preferably at least 10% of the surface area of the electronics casing comprises perforations, preferably at least 20%, preferably at least 50%.

[0053] Preferably, the electronics casing comprises an opening into the compartment for inserting the at least one electronic component, wherein the opening preferably faces an exterior of the bladder and is closed by an inner surface of the bladder the electronics casing is attached to the bladder about the periphery of the opening.

[0054] An opening as used in this application can be understood to mean a hole, slot, or other such gap the casing sufficiently large to allow for the one or more electronic component to pass through. Such an opening allows for the easy placement and orientation of the at least one electronic component within the inflatable ball.

[0055] Preferably, the electronics casing is attached to the bladder about the periphery of the opening, preferably via a flange of the electronics casing.

[0056] This allows the electronics casing to be inserted into the bladder and attached to the bladder during manufacture. The electronics casing should be attached to the bladder about the periphery of said opening. For example, the casing may comprise a flange which engages with a surface of the bladder and which is attached or sealed to the bladder around the opening through the bladder.

[0057] Preferably, the electronics casing defines the compartment by a substantially concave portion of the electronics casing.Substantially concave meaning that the electronics casing recesses inwardly, in such a way that it creates a space which can define the compartment. This is a convenient way to define a recessed space in which the electronic component may be housed adjacent to the inner surface of the inflatable interior of the ball. This concave portion of the electronics casing preferably faces the exterior of the bladder, so that the opening into the concavity may define the opening, referred to above, through which the electronic component may be inserted.

[0058] A bladder may be used to describe any component which provides an inflatable ball with its general shape and rigidity once inflated. A bladder may be elastic and may be made of rubber or any other elastic polymer, or non-elastic and made of a stiff polymer, for example. The bladder defines an inflatable interior of the ball allowing for inflation of the inflatable ball to a substantially rigid form. The bladder wall is considered to be any part of the bladder that defines the perimeter between the inside and the outside of the bladder. This will generally be a thin membranelike structure, but may also include integrally moulded wall features, such as a mounting point for the electronic device, or feature regions adhered over an opening through the bladder to make the bladder airtight. For example, some embodiments may feature a pocket-like recess into which the electronics are inserted that is moulded into the bladder wall or arranged in an opening through the bladder.

[0059] A bladder is usually encased in a layer of material which forms an outer surface of an inflatable ball, which is often the case for traditional soccer balls. However, the bladder itself may form the outermost layer of the inflatable ball. The bladder may also have additional layers between itself and an outer layer. Any outermost layer may be used with the present arrangement.

[0060] The devices will generally be arranged on or over an inside surface of the bladder wall. That is, they will generally be located inside the inflatable interior defined by the bladder wall. In this position, the devices are less likely to interfere with the external appearance or feel of the ball. However, in some embodiments the devices could be arranged on the outer surface of the bladder wall, particularly in a recessed pocket in the bladder wall.The term “distributed balancing mass” will be understood to encompass several discrete balancing mass elements, that can be individually positioned on or over the bladder wall around the second point, or a single balancing mass element whose shape and / or dimensions allow it to extend at least partially around the second point, preferably at least 50% of the way around the second point, most preferably substantially entirely around the second point. As will be discussed in more detail below, an example of a suitable singular balancing mass element may be a continuous strip that may, for example, extend in a closed loop around the second point.

[0061] It should be noted that a balancing mass element may also be provided substantially at the second point in addition to those spaced around the second point. Preferably all balancing mass elements that are provided in the ball are provided closer to the second point than the first point and preferably no balancing mass element is arranged at the second point; however, this is not essential. Preferably, all balancing mass elements are provided in a range more than 50% and less than 95% of the distance along the bladder wall from the first point to the second point, more preferably in a range more than 55% and less than 90% of the distance along the bladder wall from the first point to the second point.

[0062] In one option of present aspect, the distributed balancing mass comprises at least four balancing mass elements, the balancing mass elements being arranged substantially at or substantially evenly distributed by mass with respect to each of at least four balancing points equally spaced around the second point and closer to the second point than the first point. In comparative examples, the one or more balancing mass elements comprises one or more balancing mass elements arranged substantially at or substantially evenly distributed by mass with respect to each of at least two balancing points equally spaced around the second point, preferably at least three balancing points equally spaced around the second point. It would also be possible for balancing mass elements arranged substantially at or substantially evenly distributed by mass with respect to each of at least six balancing points equally spaced around the second point, or at least nine balancing points equally spaced around the second point. As will be describedbelow, preferably the number of balancing mass elements is a multiple of three. Each balancing mass element may be located substantially at a respective balancing mass point. Alternatively, a plurality of balancing mass elements may be divided into a plurality of sets of balancing mass elements, wherein each set of balancing mass elements is substantially evenly distributed by mass with respect to a respective balancing point. A set of balancing mass elements may be considered evenly distributed by mass with respect to a balancing point when the centre of mass of the set of balancing mass elements substantially coincides with the balancing point or wherein the balancing point is the point on the surface of the bladder closest to the centre of mass of the set of balancing mass elements. It should be noted here that each balancing point will typically be a point on the bladder wall; however, the balancing points could also be points over the bladder wall. For example, if the at least one device is inset towards the centre of the ball from the bladder wall, then it may be desirable to balance the at least one device with respect to balancing points that are likewise inset. This could be done by mounting the balancing masses so that they are spaced away from the inside surface of the bladder wall.

[0063] It is particularly advantageous in terms of balancing to have three balancing points, so that the balancing masses and the first point and / or the centre of mass of the at least one device define the vertices of a tetrahedron. However, when few balancing points are used, as is the case here, this may require these balancing mass elements to be individually quite large. It was found that that this can lead to irregular bouncing of the ball if the ball bounced close to one of these balancing mass elements. However, the use of a plurality of sub-masses to form the balancing mass elements can reduce or remove this negative effect. In comparative examples, a plurality of balancing mass elements may be evenly distributed by mass with respect to each balancing point. For example, a respective set of balancing mass elements may be distributed around each balancing point, so that the centre of mass of that set substantially coincides with the respective balancing point. However, in accordance with the present aspect, at least four balancing mass elements at four balancing points are used, or one ormore balancing mass elements arranged along tracks are used, which avoids the problems noted above

[0064] In comparative examples, the distributed balancing mass is one in which the device and the balancing mass elements are arranged at the four vertices of a substantially regular tetrahedron. In some such examples, the one or more balancing mass elements comprises one or more balancing mass elements arranged substantially at or substantially evenly distributed by mass with respect to each of three balancing points (preferably evenly) spaced around the second point, the three balancing points together with the first point and / or the centre of mass of the of the at least one device preferably defining four vertices of a tetrahedron, most preferably a substantially regular tetrahedron. In some cases, the mass distribution of the at least one device may be such that a substantially regular tetrahedron shape is not ideal for balancing; however, it may be preferred that the three balancing points are nonetheless evenly spaced around the second point, e.g. so that the three balancing points define three vertices of an equilateral triangle. This (regular) tetrahedron shape is particularly suited to moving the centre of mass towards the centre of the ball while also preventing the appearance of preferred rotation axes of the ball.

[0065] Since three balancing mass elements that, together with the first point / centre of mass of the at least one device, define a regular tetrahedron results in a substantially perfectly balanced ball where all have the same mass, consider the case in which the balancing masses each have half the mass of the at least one device. This will balance half of the mass of the at least one device. Next, consider rotating the tetrahedron around the axis passing through the first point / centre of mass of the of the at least one device and through the centre of the three balancing points. If three more balancing points are defined by this new tetrahedron, and three more balancing masses placed at these new balancing points, each having half the mass of the at least one device, then these will again balance half the mass of the at least one device. The combined effect of the six balancing masses, each with half the mass of the at least one device, will be essentially identical to the effect of three balancing masses each having the samemass as the at least one device. In accordance with this principle, the ball may comprise at least six balancing mass elements arranged substantially in a single plane, wherein each balancing mass element has two corresponding balancing mass elements which, together with the first point and / or the centre of mass of the at least one device, define four vertices of a substantially regular tetrahedron. In other words, the ball may comprise at least six balancing mass elements arranged substantially in a single plane, wherein each balancing mass element has, among the other of the at least six balancing mass elements, two corresponding balancing mass elements, wherein each balancing mass element together with its two corresponding balancing mass elements and together with the first point and / or the centre of mass of the at least one device defines four vertices of a substantially regular tetrahedron. It will be appreciated that these balancing masses can be divided into smaller and smaller mass elements defining more and more substantially regular tetrahedra together with the first point and / or the centre of mass of the at least one device, tending towards the balancing mass elements defining a circular track along the bladder wall defining a cone together with the first point. In line with the above, it will be preferred that the number of balancing masses is a multiple of three, i.e. such that each set of three may define a tetrahedron with the first point. However, once the balancing mass elements are sufficiently small and sufficiently many, this multiple of three preference for good balancing becomes less important, i.e. the effect of omitting one or two balancing mass elements becomes negligible.

[0066] As indicated above, in a comparative example, a preferred arrangement may be one in which the first point and the distributed balancing mass define a cone shape, with the first point being the tip of the cone and the distributed balancing mass extending around the base of the cone. Much like the tetrahedron shape described above, this shape is particularly suited to moving the centre of mass towards the centre of the ball while also preventing the appearance of preferred rotation axes of the ball.

[0067] In some embodiments, the distributed balancing mass comprises at least five balancing mass elements arranged substantially at or substantially evenlydistributed by mass with respect to five balancing points equally spaced around the second point, preferably at least eight balancing mass elements arranged substantially at or substantially evenly distributed by mass with respect to eight balancing points equally spaced around the second point, most preferably at least ten balancing mass elements arranged substantially at or substantially evenly distributed by mass with respect to ten balancing points equally spaced around the second point. More balancing mass elements arranged at more balancing points reduces the required mass of each balancing mass element and thus reduces irregular bouncing. As more balancing mass elements are arranged at more balancing points, the balancing mass elements will more closely define a cone shape with the first point, as discussed above, which is advantageous in how it balances the mass of the electronic device.

[0068] In some cases, the one or more balancing mass elements may comprise one or more mass balancing elements arranged along one or more tracks along the bladder wall defining all or part(s) of the circumference of a circle or an ellipse, wherein preferably the first point lies perpendicular to the plane of the circle or the ellipse from the centre of the circle or the ellipse. A cone with a circular base is particularly suited to spherical balls. A cone with an elliptical base is suited to balls whose shape is a prolate spheroid, such as rugby balls or American footballs. It will be noted that these latter ball shapes already have a preferred rotation axis; however, the present balancing arrangement preserves this balance so that a ball with an electronic device, balanced in this way, behaves substantially the same as a standard ball without any electronic devices. It will be appreciated that the “tracks” described here could be formed by continuous balancing mass elements, such as a strip, or could be formed by a series of balancing mass elements arranged in a line, as will be described in more detail below. A single balancing mass element may define a track where the balancing mass element is elongate along the surface of the bladder, preferably having a length along the surface of the bladder at least twice as long as a width along the bladder wall, more preferably at least three times as long, more preferably at least five times as long, most preferably at least ten times as long as the width. A series of balancing mass elements may define a track where at least three balancing mass elements areprovided, with each balancing mass element being spaced from the next balancing mass element by no more than 5 cm, preferably no more than 4 cm, preferably no more than 3 cm, most preferably no more than 2cm. The closer the elements are together, the more may be arranged in a track of given length and so the smaller each balancing mass element may be. Adjacent balancing mass elements within the track are preferably spaced from one another along the bladder wall by a distance that is no more than twice the length of each balancing mass element along the direction of spacing, preferably no more than the length of each balancing mass element along the direction of spacing. Preferably, where a track is defined by a series of balancing mass elements, the track comprises at least five balancing mass elements, most preferably at least ten balancing mass elements.

[0069] In another comparative example, the at least one device comprises a first device and a second device, wherein the one or more tracks along the bladder wall pass through first and second balancing points spaced around the second point and define part(s) of the circumference of a circle or an ellipse passing between the first and second devices. In one variant of this embodiment, the first device is positioned at or over a first vertex of a regular tetrahedron whose vertices are located in the bladder wall of the ball, and the second device is positioned at or over a second vertex. In this case, the first and second balancing points may be the third and fourth vertices of this tetrahedron. The balancing masses then define one or more tracks passing through the first and second balancing points and preferably also the second point.

[0070] In the comparative example, the one or more tracks extend along at least 50% of the circumference of the circle or ellipse, preferably at least 60%, more preferably at least 70%, more preferably at least 80%, most preferably wherein the wherein the one or more tracks extend along substantially the whole of the circumference of the circle or ellipse. As mentioned, there may be at least two separate tracks extending along at least 50%, 60%, 70%, or 80% of the circumference or substantially all of the circumference of the circle or ellipse, preferably at leastthree separate tracks. Alternatively, there may be one continuous track, preferably extending along substantially all of the circumference of the circle or ellipse.

[0071] In a conventional arrangement in which the mass of the device is offset by a balancing mass on the opposite side of the ball, the balancing mass generally has substantially the same mass as the mass of the device. However, in the present embodiment, balancing masses are provided between the first and second points. Therefore, typically, the balancing masses will have a total mass of at least 1.5 times the mass of the at least one device, preferably at least 2 times the mass of the at least one device, more preferably at least 2.5 times the mass of the at least one device, most preferably at least 3 times the mass of the at least one device. Preferably, the balancing masses will have a total mass of less than 8 times the mass of the at least one device, preferably less than 6 times the mass of the at least one device, most preferably less than 4 times the mass of the at least one device. In particular, preferably the balancing masses have a total mass of between 2 times and 4 times the mass of the at least one device. The precise mass required will depend on the arrangement of the at least one device and the distance of the balancing mass elements between the first and second points. Indeed, in the above described arrangement in which a substantially regular tetrahedron shape or a cone shape is defined, it may be ideal for the balancing masses to have a total mass of approximately 3 times the mass of the at least one device.

[0072] In some embodiments, the one or more balancing mass elements are provided by balancing mass elements in or on a cover of the inflatable ball, the cover surrounding the bladder. This may be provided by small weights stitched into the cover for example; however, as will be described above, a preferred thin form balancing mass element is a weighted strip or patch, which could be incorporated into the cover.

[0073] As alluded to above, one way that the balancing mass element(s) may be formed is by providing one or more continuous strips or patches, preferably adhesive strips or patches, attached on or over the bladder wall. Strips are preferred, as they may be used as tracks, described above, and may extend along thecircumference of the circle or ellipse along which the distributed balancing mass is arranged. Such strips or patches may be weighted with a relatively dense material, such as a rubber. The use of strips or patches allows relatively heavy balancing mass elements to be provided with thin, easy to apply elements. The primary advantage of using these strips or patches is that they may be applied to a conventional ball bladder, meaning that balls with and without electronic devices can be manufactured using the same bladder design. They may also be thin enough that they can be applied to or over an outer surface of the bladder, allowing the balancing to be performed after the ball has been assembled and inflated, which prevents the balancing masses from interfering with inflated shape of the ball. Indeed, it will generally be preferred for the strip or patch to be as thin as possible, and so preferably each strip or patch has a thickness of no more than 5 mm, preferably no more than 4 mm, more preferably no more than 3 mm, even more preferably no more than 2 mm, most preferably no more than 1 mm, to facilitate application to an outer surface of the bladder. Alternatively, these types of balancing mass elements, as well as others, could be applied on or over an inner surface of the bladder wall. However, applying on or over the outer surface of the bladder allows for application after inflation of the bladder and also allows the bladder to be tested for balancing and rebalanced if necessary. As indicated above, while, in some embodiments, it may be preferable to attach the strips or patches on the inner or outer surface of the bladder wall, in particularly preferred embodiments, each continuous strip is provided in or attached to a cover of the inflatable ball, the cover surrounding the bladder.

[0074] A problem with providing the balancing mass elements by continuous strips is that the strip can affect how the bladder wall stretches when it inflates. Large strips of continuous thickness may therefore distort the inflated shape of the ball. Therefore, in some examples, each continuous strip comprises a plurality of increased thickness portions of the strip separated (e.g. along the length of the strip) by reduced thickness portions of the strip. By providing thinner portions of the strip, which may stretch more easily when the ball is inflated, the effect of the strip on the shape of the ball is reduced. Preferably, each increased thickness portion has a largest dimension along the length of the continuous strip of no morethan 4 cm, preferably no more than 2 cm, more preferably no more than 1 cm. The stretching of the strip may also be facilitated by very thin reduced thickness portions, therefore preferably, the thickness of the increased thickness portions of the continuous strip is at least twice the thickness of the thinnest part of the continuous strip, preferably at least three times the thickness of the thinnest part of the continuous strip, more preferably at least four times the thickness of the thinnest part of the continuous strip. The strip may also have a smallest thickness between each increased thickness portion of no more than 0.5 cm, preferably no more than 0.3 cm, more preferably no more than 0.2 cm, most preferably no more than 0.1 cm.

[0075] To aid with aligning one or more strips, preferably opposing ends of each continuous strip define complementary non-linear or obliquely angled end edges such that opposing end edges of one or more continuous strips may be aligned to one another by the complementary end edges. The ends of the one or more strips may therefore fit together in a jigsaw-like manner to aid alignment of the ends of the strip(s).

[0076] An alternative balancing mass type (although it is also envisaged that a mixture of types may be used) is to provide one or more balancing mass elements formed integrally with the bladder wall. This allows the bladder to be produced with the balancing mass elements already provided in the bladder wall fora predetermined device arrangement, which removes the requirement for application or insertion of separate balancing mass elements. For example, if the bladder is injection moulded, then the balancing mass elements may be defined by the injection mould.

[0077] In some examples, a plurality of balancing mass elements formed integrally with the bladder wall are formed by increased wall-thickness portions of the bladder wall. It will be appreciated that the increased wall-thickness portions have a greater wall thickness than the wall thickness of the majority of the bladder wall, or a greater wall thickness than the median wall thickness of the bladder wall. Typically, the majority area of the bladder wall, i.e. more than 50% will be of substantially constant thickness, with the increased wall thickness portions havinga greater thickness than this substantially constant thickness across the majority area of the bladder wall. A minority area of the bladder wall, i.e. less than 50%, preferably less than 25%, more preferably less than 10%, most preferably less than 5%, will have an increased wall thickness compared to the remaining bladder wall area.

[0078] A problem with providing the balancing mass elements by increased wall thickness portions of the bladder wall is that the thickness of the bladder wall can affect how the bladder wall stretches when it inflates. Large contiguous regions of increased bladder wall thickness may therefore distort the inflated shape of the ball. As has been discussed above, and as is discussed further below, this can be overcome via the use of a balancing mass comprising a plurality of sub-masses. In some examples, preferably, each increased wall-thickness portion has at least one lateral dimension of no more than 2 cm, preferably no more than 1 cm, more preferably no more than 0.5 cm. More preferably, each increased wall-thickness portion has a largest lateral dimension of no more than 2 cm, preferably no more than 1 cm, more preferably no more than 0.5 cm. Here, a lateral dimension refers to a dimension along the bladder wall surface, i.e. generally perpendicular to the bladder wall thickness direction (accounting for the fact the bladder wall defines a curved surface). By providing that the increased wall thickness portions are small in at least one, preferably each lateral direction, the effect on the inflated shape of the bladder may be minimised. Indeed, preferably, each increased wall-thickness portion of the bladder wall is surrounded by a portion not having the increased wall thickness.

[0079] In some examples, each increased wall-thickness portion projects from an inner surface of the bladder wall towards the centre of the inflatable interior of the ball. This prevents the increased wall-thickness portions from affecting the external shape or appearance of the inflated ball. While preferred, the increased wallthickness portions could project outwards, or could project both inwards and outwards, in which case a suitable cover may need to be provided to cover or disguise the projections.In some examples, the wall thickness of the increased wall-thickness portions is no more than five times the wall thickness of the thinnest part of the bladder wall, preferably no more than four times the thickness, even more preferably no more than three times the thickness, most preferably no more than twice the thickness of the thinnest part of the bladder wall. Alternatively, there may be localised regions of decreased thickness, in which case the wall thickness of the increased wall-thickness portions may be no more than five times the median wall thickness or the substantially constant wall thickness of the majority area of the bladder wall, preferably no more than four times the thickness, even more preferably no more than three times the thickness, most preferably no more than twice the median wall thickness or the substantially constant wall thickness of the majority area of the bladder wall.

[0080] In some examples, where the balancing mass elements are formed integrally with the bladder wall, preferably there are at least 10 balancing mass elements, more preferably at least 15 balancing mass elements, most preferably at least 20 balancing mass elements. It will be appreciated that, in cases where the balancing mass elements are formed integrally with the bladder wall, they are nonetheless considered discrete balancing mass elements where they are separate projections separated from one another by bladder wall having the standard bladder wall thickness.

[0081] It will generally be preferred for any devices, including all electronic devices, to be applied at one location in the ball. Therefore, preferably, the at least one device balanced by the distributed balancing mass is mounted at a substantially single point on or over the bladder wall. This simplifies the balancing arrangement and simplifies manufacture. While preferred, the present technique can be extended to balance devices located in multiple positions on or over the bladder wall. Indeed, as indicated above, this can be done by balancing with respect to the centre of mass of several devices at different positions.

[0082] In some embodiments, it may be preferable to provide multiple devices at different positions in the ball. One approach is for the first device to be provided at a first vertex of a substantially regular tetrahedron, a second device (preferably havingsubstantially the same mass as the first device) to be provided at a second vertex of a substantially regular tetrahedron, and for the one or more balancing mass elements to be arranged substantially at or substantially evenly distributed by mass with respect to two other vertices of the substantially regular tetrahedron.

[0083] Another approach may be to balance multiple devices, or multiple sets of devices, separately. In particular, the at least one device may be a first device or first set of devices, and the ball may further comprise a second device or second set of devices mounted on or over the bladder wall such that a centre of mass of the second device or second set of devices is located away from a centre of the inflatable interior of the ball, the centre of mass of the second device or second set of devices defining a third point on the bladder wall coincident with or closest to the centre of mass of the second device or second set of devices and a fourth point on the bladder wall opposite the third point; and a second distributed balancing mass for at least partially rotationally balancing the mass of the second device or second set of devices, the distributed balancing mass comprising one or more balancing mass elements on or over the bladder wall, the one or more balancing mass elements being arranged at a plurality of locations spaced around the fourth point on the bladder wall and closer to the fourth point than the third point, and wherein the second distributed balancing mass comprises one of: c) at least four balancing mass elements, the balancing mass elements being arranged substantially at or substantially evenly distributed by mass with respect to each of at least four balancing points equally spaced around the fourth point and closer to the fourth point than the third point; or d) one or more mass balancing elements arranged on or over the bladder wall along one or more tracks along the bladder wall defining substantially all or one or more parts of the circumference of a circle or an ellipse. Indeed, if one considers that one or more devices (the first device or first set) may be balanced by the techniques described above, the result may be a ball that is balanced essentially identically to a ball without the devices or balancing masses. Therefore, the second device or second set of devices, may be assessed and balanced entirely separately from the first device or first set. This approach may be preferred when the multiple devices are spaced relatively far apart, but be used for any spacing of the device sets. It will be noted thatpreferably the second device or second set of devices comprises at least one electronic device. Any of the balancing approaches used above for the one or more devices (referred to in the present context as the first device or the first set of devices) may be used for the second device or second set of devices, including those of comparative examples. In particular, the second distributed balancing mass may comprise one or more balancing mass elements arranged substantially at or substantially evenly distributed by mass with respect to each of at least two balancing points equally spaced around the fourth point, preferably at least three balancing points equally spaced around the fourth point. The second distributed balancing mass could also comprise one or more balancing mass elements arranged substantially at or substantially evenly distributed by mass with respect to each of at least three balancing points spaced around the fourth point, the three balancing points together with the third point and / or the centre of mass of the of the second device or second set of devices defining four vertices of a substantially regular tetrahedron. The second distributed balancing mass could also comprise at least six balancing mass elements arranged substantially in a single plane, wherein each balancing mass element has two corresponding balancing mass elements which, together with the third point and / or the centre of mass of the of the second device or second set of devices, define four vertices of a substantially regular tetrahedron. Alternatively, the second distributed balancing mass may comprise one or more mass balancing elements arranged along one or more tracks along the bladder wall defining all or part(s) of the circumference of a circle or an ellipse, wherein preferably the third point lies perpendicular to the plane of the circle or the ellipse from the centre of the circle or the ellipse.

[0084] In all embodiments, preferably each device being balanced comprises an electronic device, although other devices that contribute to the mass of the ball could also be balanced in this way. Preferably, the or each electronic device comprises one or more of: a battery, a wireless charging module, an accelerometer, a gyroscope, a pressure sensor, a magnetometer, a pressure transducer and a location tracking device, such as an ultra-wideband transmitter and / or receiver.The present technique is most advantageous in application to spherical balls, which generally do not have much if any of a preferred rotation axis. Therefore, preferably, the bladder defines a substantially spherical inflatable interior of the ball. While this is preferable, the present technique can also be applied to other ball shapes, such as prolate spheroid shapes.

[0085] Preferably, the inflatable ball is an inflatable sports ball, preferably a soccer ball, basketball, netball, volleyball, or handball. However, other ball types may also be used.

[0086] In accordance with a second aspect of the invention, there is provided a method of manufacturing an inflatable ball, the method comprising: providing a bladder having a bladder wall defining an inflatable interior of the ball; providing at least one device mounted on or over the bladder wall such that a centre of mass of the at least one device is located away from a centre of the inflatable interior of the ball, the at least one device including at least one electronic device, the centre of mass of the at least one device defining a first point on the bladder wall coincident with or closest to the centre of mass of the at least one device and a second point on the bladder wall opposite the first point; and providing a distributed balancing mass for at least partially rotationally balancing the mass of the at least one device, the distributed balancing mass comprising one or more balancing mass elements provided on or over the bladder wall, the one or more balancing mass elements being arranged at a plurality of locations spaced around the second point on the bladder wall and closer to the second point than the first point, wherein one of the one or more balancing mass elements comprises a valve of the inflatable ball; and / or wherein one of the one or more balancing mass elements is attached on or over the bladder wall and comprises a plurality of sub-masses that are interconnected by one or more interconnecting portions, such that the plurality of sub-masses may move relative to one another during deformation of the bladder wall by stretching or bending of the interconnecting portions.

[0087] The method according to this aspect corresponds to a method of manufacturing an inflatable ball according to the first aspect, and so each of the preferredfeatures and advantages discussed above applies equally to the method of this aspect of the invention.

[0088] In some embodiments, providing the distributed balancing mass comprises attaching one or more continuous strips or patches, preferably adhesive strips or patches, on or over the bladder wall. As mentioned above, this may take place in a step after inflation of the bladder.

[0089] In other embodiments, providing the bladder comprises moulding the bladder, and providing the distributed balancing mass comprises moulding one or more balancing mass elements integrally with the bladder wall when moulding the bladder. Moulding one or more balancing mass elements integrally with the bladder wall when moulding the bladder may comprise moulding a plurality of increased wall-thickness portions of the bladder wall. These increased wallthickness portions are the same as described above.

[0090] Preferably, a balancing mass element comprising a plurality of sub-masses that are interconnected by one or more interconnecting portions is formed by cutting, etching, or otherwise dividing or removing material provided in a unitary precursor balancing mass element.

[0091] In a further preferable implementation, when a balancing mass element is provided, the inflatable ball is inflated and the interconnecting portions in the balancing mass element are configured such that they tear or separate from the sub-masses they connect. For example, the interconnecting portions may be formed with a small thickness and / or with perforations and / or etchings such that they tear during inflation.

[0092] BRIEF DESCRIPTION OF DRAWINGS

[0093] The invention will now be discussed with reference to the accompanying drawings, of which:

[0094] Figure 1 is a schematic cross-section of a first example of an inflatable ball;Figure 2A schematically illustrates a balancing arrangement for the inflatable ball of Figure 1, Figure 2B is an enlarged view of the distributed balancing mass in region A, and Figure 2C illustrates a variant balancing arrangement;

[0095] Figure 3A schematically illustrates another balancing arrangement for the inflatable ball of Figure 1, and Figures 3B and 3C are an enlarged views of the distributed balancing mass in region B;

[0096] Figure 4 schematically illustrates another balancing arrangement for the inflatable ball of Figure 1;

[0097] Figure 5A schematically illustrates another balancing arrangement for the inflatable ball of Figure 1 and Figure 5B is an enlarged view of the distributed balancing mass in region C;

[0098] Figure 6A schematically illustrates another balancing arrangement for the inflatable ball of Figure 1, Figure 6B is an enlarged view of a first variant of the distributed balancing mass in region D, Figure 6C is an enlarged view of a second variant of the distributed balancing mass in region D, Figure 6D is an enlarged view of a third variant of the distributed balancing mass in region D, and Figure 6E is a schematic view of the distributed balancing mass used in Figures 6C and 6D;

[0099] Figure 7A schematically illustrates another balancing arrangement for the inflatable ball of Figure 1 and Figure 7B is an enlarged view of the distributed balancing mass in region E;

[0100] Figure 8A schematically illustrates another balancing arrangement for the inflatable ball of Figure 1 and Figure 8B is an enlarged view of the distributed balancing mass in region F;

[0101] Figure 9 is a schematic cross-section of a second example of an inflatable ball;

[0102] Figure 10 schematically illustrates a balancing arrangement for the inflatable ball of Figure 9;Figure 11 is a schematic cross-section of a third example of an inflatable ball;

[0103] Figure 12 schematically illustrates a balancing arrangement for the inflatable of Figure 11;

[0104] Figure 13 schematically illustrates a balancing arrangement for another inflatable ball;

[0105] Figure 14 schematically illustrates a balancing arrangement for another inflatable ball;

[0106] Figures 15Aand 15B schematically illustrate two different balancing arrangements for another inflatable ball;

[0107] Figure 16 schematically illustrates another balancing arrangement for the inflatable ball of Figure;

[0108] Figure 17 schematically illustrates a balancing arrangement for another inflatable ball;

[0109] Figures 18Aand 18B schematically illustrate a balancing arrangement for another inflatable ball;

[0110] Figure 19 schematically illustrates a balancing arrangement for another inflatable ball;

[0111] Figure 20 schematically illustrates a balancing arrangement for another inflatable ball;

[0112] Figure 21 schematically illustrates an electronics casing in fluid communication with the interior of the ball; and

[0113] Figure 22 schematically illustrates an electronics casing in fluid communication with the interior of the ball.DETAILED DESCRIPTION

[0114] Figure 1 shows a first example of a ball 1 in need of balancing in accordance with the present invention. The ball comprises a bladder 10 comprising a bladder wall 11, which defines a spherical inflatable interior of the ball. The bladder wall 11 is continuous except for a circular opening, at which a valve 4 is bonded to the bladder wall 11 to make the interior of the bladder airtight and to allow for the bladder to be inflated via the valve 4. Inside the ball is an electronic device 2. The electronic device 2 is contained in a housing 3 (which may also be considered a device within the meaning of this disclosure), which is adhered to an inner surface of the bladder wall 11. The electronic device may comprise one or more of a battery, a wireless charging module, an accelerometer, a gyroscope, a pressure sensor, a magnetometer, a force transducer and a location tracking device, such as an ultra-wideband transmitter and / or receiver. The electronic device and housing may have a mass of, for example, 15 grams. By its position adjacent to the inner surface of the bladder wall 11, the electronic device causes the ball to have a different centre of gravity than a ball without the electronic device. In order that balls without electronic devices feel substantially the same to a user, the mass of the electronic device and housing need to be balanced.

[0115] As will now be described with respect to Figures 2Ato 8B, the present invention uses a distributed balancing mass 12 comprising one or more mass elements 13 to balance the mass of the electronic device 2 and housing 3.

[0116] To maintain the rotational balance of the ball, as it was before the introduction of electronics 2, the electronics and the distributed balancing mass 12 should not contribute any unbalanced forces or moments when the ball is spinning about any axis.

[0117] To achieve this, it is preferable that two criteria are substantially met. Assume there is a ball with initial centre of mass centred at the origin. Then let there be N masses introduced. Let the i’th mass have position vector^ and mass m,. The ball will be statically balanced, and the dynamic centrifugal forces will sum to zero if the centre of gravity of the electronics and the added masses coincide with theball’s original centre of mass. By the earlier statement this must be the origin, therefore:

[0118]

[0119] The second criterion relates to ensuring there are no unbalanced moments when the ball is rotated about any axis. The definition of the inertia tensor for rigid body rotation with point masses is:

[0120]

[0121] It can be shown there will be no unbalanced moments if the second term in Equation (2) satisfies the following condition:

[0122]

[0123] The above condition says, firstly, that the added masses and their positions must be such that the products of inertia are all zero, and secondly, that the principal moments of inertia are all equal.

[0124] Several embodiments of balancing a sports ball will now be described, which either fulfil the above criteria, i.e. the centre of gravity of the electronics and the added masses coincide with the centre of mass of the ball and the principal moments of inertia are all equal, or which are closer to these criteria than many other conventional balancing methods.

[0125] When one considers dynamically balancing a sports ball, the fewest masses is often the most desirable solution and the above criteria can be fulfilled with thefewest masses by using a tetrahedral balancing method, which is demonstrated in Figures 2Aand 2B.

[0126] Figure 2A shows a tetrahedral balancing arrangement of the spherical ball shown in Figure 1. In this example, the centre of mass of the electronic device 2 and the housing 3 is substantially coincident with the first point 101 on the bladder, which in the Figure is the uppermost point of the bladder wall 11. Opposite the first point 101 is a second point 102. The first point 101 is treated as the first vertex in a regular tetrahedron whose other three vertices 111, 112, 113 also coincide with the bladder wall 11. In other words, the regular tetrahedron that is circumscribed by the sphere of the bladder wall. The other three vertices of this regular tetrahedron, which are referred to herein as balancing points, define the preferred locations of three balancing masses for offsetting the balance of the electronic device 2 and its housing 3. As shown in Figure 2A, a straight line along the bladder wall passing through these three balancing points 111, 112, 113 defines a circle. The first and second points 101 , 102 are both perpendicularly offset from the plane of this circle from the centre point of this circle. This plane, and all three balancing points 111, 112, 113 are closer to the second point 102 than the first point 101.

[0127] The balancing masses located at the three balancing points 111, 112, 113 are collectively referred to as a distributed balancing mass 12. Figure 2B shows an enlarged region A of Figure 2Ain cross-section and illustrates one balancing mass element 13 of the distributed balancing mass 12. Figure 2B shows the bladder wall 11 as flat for simplicity, but it will be appreciated that the inner surface of the bladder wall is concave in practice. In this example, the balancing mass element 13 is a block of rubber that has been moulded to have the correct size and shape, i.e. suitable for adhering to the concave inner surface of the bladder wall 11 , and is adhered to the inside of the bladder wall 11 by an adhesive 13a. To prepare the inner surface of the bladder and the balancing mass elements for adhesion, the bonding surfaces should be sanded and cleaned with a suitable solvent. The adhesive 13a, which should be a contact adhesive, should be applied to the clean surfaces and left for ten minutes. A second application of the contact adhesive should be performed, left for ten minutes, and then the bonding surfaces pressedtogether and allowed to cure for 24 hours. Each balancing point 111 , 112, 113 is provided with a corresponding balancing mass element 13 in the manner illustrated in Figure 2B and as described above. If the electronic device 2 and the housing 3 have a combined mass of, for example, 15 grams, then each balancing mass element 13 at each balancing point 111, 112, 113 should have a mass of approximately 15 grams, such that the total mass of the distributed balancing mass is three times that of the electronic device 2 and the housing 3. It will be noted that the mass of the valve is not taken into account here. This choice is made in situations where it may be generally desired for a ball with electronic devices to behave as similarly as possible to one without the electronic devices. It would, however, be possible to factor in the mass of the valve to achieve a ball whose total centre of mass is substantially at the centre.

[0128] While this tetrahedral arrangement can satisfy the criteria of the two equations set out above and may be considered the mathematically most efficient arrangement, this arrangement requires relatively large balancing mass elements 13 at each of the three balancing points 111, 112, 113. This can cause irregular bouncing of the ball, particularly when it bounces close to one of the balancing mass elements 13. An alternative arrangement is illustrated in Figure 2C. Here, four balancing mass elements 13 are provided respectively at four balancing points 111, 112, 113, 114. These four balancing points 111, 112, 113, 114 are arranged in the same plane as the three balancing points 111, 112, 113 of Figure 2A, and are equally spaced around the second point 102, such that the four balancing points 111, 112, 113, 114, together with the first point 101, describe a square based pyramid. By providing four balancing mass elements 13 instead of three, the mass of each may be reduced while still achieving a similar balancing effect to Figure 2A. The reduction in mass of the balancing mass elements 13 helps to prevent irregular bouncing of the ball. It will be appreciated that this principle may be taken further to further reduce the mass of each balancing mass element. For example, five balancing mass elements may be arranged at five balancing points equally spaced around the second point 102. As each new balancing point is provided, the required mass of the balancing mass element is reduced, further reducing the impact of the balancing mass elements on the bouncing of the ball.While the above tetrahedral arrangement can satisfy the criteria of the two equations set out above and may be considered the mathematically most efficient arrangement, and the square-based pyramid arrangement reduces the mass of each balancing mass element, applying three or more individual balancing mass elements is a time-consuming and labour-intensive process. Therefore, several alternative solutions for achieving substantial balancing of the ball, in line with the above equations, that are more procedurally straightforward are also suggested and described with reference to Figures 3A to 8B.

[0129] Figure 3A illustrates an alternative balancing arrangement for balancing the ball of Figure 1. Instead of using three essentially point-masses on the vertices of the tetrahedron’s base at the balancing points 111, 112, 113, the masses can be split into a much larger number of smaller point masses around the base of an inscribed cone. Figure 2A showed a straight line along the bladder wall 11 passing through the three balancing points 111, 112, 113, defining a circle. Instead of providing a single mass element at each balancing point, the mass is distributed evenly along this line, as shown in Figure 3A. The distributed mass element 12 is thus defined by a track of small mass elements 13 that defines the circumference of a circle. Now, each mass element 13 is much smaller than the three point masses provided at the balancing points 111, 112, 113 in the embodiment of Figure 2A. These masses may now be of a size that they can be produced by directly moulding the mass elements into the bladder wall 11, particularly by providing localised regions of increased bladder wall thickness.

[0130] Figures 3B and 3C shows an enlarged region B of Figure 3A in cross-section to illustrate these integrally moulded balancing mass elements 13. When the bladder mould is designed, a series of recesses are provided on the surface of the mould that will define the inner surface of the bladder. In the present arrangement a series of circular recesses are provided so that the inner surface of the bladder features a row of circular protrusions 13 as the integrally moulded balancing mass elements. These circular protrusions 13 are thus provided by regions of the bladder wall 11 having increased wall thickness as a result of the recesses in the moulding tool used to mould the bladder wall. Each circular protrusion may havea thickness of approximately twice that of the surrounding bladder wall thickness. Each circular protrusion may have a diameter of no more than 0.5 cm and may be separated from one another by an intervening bladder wall portion 11a that does not have the increased wall thickness. As a result, when the bladder is inflated, the bladder is still able to expand without any significant restriction that would be caused by large areas of increased wall thickness. As with the above embodiment, the circular protrusions, which act as the balancing mass elements 13, may have a mass of three times that of the electronic device 2 and the housing 3.

[0131] In some cases, particularly where the electronic device 2 and the housing 3 is especially heavy, it may not be possible to balance the mass with a single row of integrally moulded balancing mass elements 13 while still having them small enough and spacing them far apart enough to allow acceptable inflation of the bladder. Figure 4 shows an alternative embodiment in which three parallel tracks of integrally moulded balancing mass elements 13 are provided, each one defining the circumference of a circle to which the first point 101 is perpendicularly offset from a centre point of that circle. Each integrally moulded balancing mass element is nonetheless closer to the second point 102 (opposite the first point) than the first point 101. The balancing mass elements 13 are nonetheless formed in the same manner as those described with reference to Figure 3. Again, the total mass of all balancing mass elements 13 may be substantially three times the mass of the electronic device 2 and the housing 3.

[0132] Figures 5A and 5B illustrate another variant using integrally moulded balancing masses arranged along tracks along the inner surface of the bladder wall 11. In this embodiment, rather than extending along the entire circumference of a circle, the integrally moulded balancing masses 13 arranged along three tracks that define an arc corresponding to part of the circumference of that circle. Each arc is of the same length and has the same number of integrally moulded balancing masses 13. The three tracks are evenly spaced apart. Accordingly, each track is effectively centred on one of the three balancing points 111, 112, 113 described with respect to Figure 2A.A downside to integrally moulded balancing elements 13 is that they need to have specialised moulding tools produced. Any changes to the design of the electronics module that changed the weight would require its own specially designed bladder. Also, the effect of integrally moulded balancing elements 13 on ball inflation can be minimised but not removed entirely. Figures 6A to 6E illustrate an embodiment that addresses these issues, while also removing the requirement in the context of the Figure 2 arrangement to attach the masses inside the bladder during assembly of the bladder.

[0133] In the embodiment of Figure 6A and 6B, instead of being formed by integrally moulded balancing elements, the distributed balancing mass 12 is formed by a continuous strip 13 as the balancing mass element, which is applied to the bladder wall 11. The strip may be a rubber strip whose mass is approximately three times that of the electronics device 2 and housing 3. In this embodiment, the rubber strip is applied to the outside of the bladder using an adhesive 13a after inflation of the bladder. The rubber strip is applied along the same track defining the circumference of a circle that the integrally formed balancing mass elements of Figure 3A were arranged on. Specifically, an equilateral triangle formed by three points along the circular track should form the vertices of a regular tetrahedron with the first point 101, which is substantially where the electronic device 2 is positioned.

[0134] In the case of the strip shown in Figure 6B, this is provided by a strip of substantially continuous thickness. This is particularly suitable for strips applied after the bladder has been assembled and inflated to a final size. However, the strip may cause problems if applied to the ball before it is fully inflated, since the thickness of the strip may inhibit the inflation of the ball. This prevents this type of strip being used effectively on the inner surface of the bladder wall. Figure 6C shows an alternative form of strip 13. In the embodiment illustrated by Figure 6C, the strip is adhered to an inner surface of the bladder wall 11 by an adhesive 13a, although it could also be used on the outside surface of the bladder wall. The strip comprises increased thickness portions 13b arranged along the strip and separated from one another by decreased thickness portions 13c of the strip. Thisarrangement is more clearly shown in Figure 6E, which shows a strip in plan view. The purpose of the increased thickness portions 13b may be to contribute significantly to the mass of the strip. Each increased thickness portion 13b may have a thickness of 5 mm and may extend 1 cm along the length of the strip, for example. The purpose of the decreased thickness portions 13c may be to hold the increased thickness portions 13b together in one continuous strip to facilitate application while also being thin enough to allow the strip to stretch with the bladder as it is inflated. Each decreased thickness portion 13c may have a thickness of 1 mm and may extend 1 cm along the length of the strip, for example. Again, the strip may be formed of rubber.

[0135] Figure 6D shows an alternative arrangement in which the same strip from Figure 6C is applied to an inner surface of a cover 15 of the inflatable ball. This cover may form the outermost layer of the ball and may be made of leather, synthetic leather, polyurethane or PVC, for example. Thus, the strip is arranged between the cover layer and the bladder. In this case, it may be desirable for the thickness of the increased thickness elements to be lower, e.g. less than 3 mm. The width of the strip may be increased to increase the overall mass of the strip. In this embodiment, the strip is adhered to the cover by an adhesive layer 13a.

[0136] It may be desirable to form the distributed balancing mass by multiple separate strips. This may allow, for example, different standardised strips of different weights to be used to precisely balance the exact mass of the electronics device in a particular ball. Figure 6E shows a strip in plan view and shows that each strip may be provided with complementary shaped end edges that are configured to fit together. In particular, a first end edge of the strip is provided with a central projection 13d. The opposing end edge of the strip is provided with a central recess 13e arranged such that the central projection 13d of one strip fits into the central recess 13e of the adjacent strip to align the strips in a jigsaw-like manner. Of course, if one long strip is to be used, these complementary end edges may be used to line up the opposing end edges of the same strip after it has wrapped around the bladder.While the embodiments of Figures 3A to 6B have all distributed the mass of the balancing mass elements 13 along tracks around the bladder wall, instead of having the essentially point masses of Figure 2, two other examples for distributing the balancing mass are shown in Figures 7A to 8B. Each of these shows balancing mass elements distributed with respect to three balancing points as shown in Figure 2A, but the same balancing mass elements could also be arranged with respect to four or more balancing points, as shown in Figure 2C.

[0137] Figures 7A and 7B show an example in which each balancing mass element 13 is formed by a relatively large patch. Like the strip of the previous embodiment, each patch 13 is applied to the outside of the bladder using an adhesive 13a after inflation of the bladder. Each patch may again be a patch of rubber or another thin flexible mass. Referring again to Figure 2A, one patch is applied centred on each of the three balancing points 111, 112, 113. Each patch may have the same mass as the electronic device 2 and housing 3, but can be conveniently applied to the outer surface of the bladder after the bladder has been inflated due to their large area and hence low thickness. Alternatively, four patches could be applied to the four balancing points of Figure 2C.

[0138] Figures 8A and 8B show an embodiment which once again use balancing mass elements 13 that are integrally formed in an inner surface of the bladder wall 11. This embodiment differs the embodiments of Figures 3A to 5B in that the balancing mass elements 13 cover three circular regions of the bladder wall, each circular region being centred on one of the three balancing points 111, 112, 113 that were described with reference to Figure 2A, although a circular region could alternatively be provided for each of the four balancing points of Figure 2C. Within each circular region, the integrally formed balancing mass elements 13 are arranged in a two-dimensional array across the inner surface of the bladder. Again, each integrally formed balancing mass element 13 may be a circular region of increased wall thickness compared to the rest of the bladder wall 11. The integrally formed balancing mass elements 13 may once again be spaced from one another by intervening wall portions 11a that do not have the increasedthickness, to minimise the effect these elements have on the inflation of the bladder.

[0139] The above embodiments have all dealt with a ball with additional mass introduced by an electronic device in one location around the periphery of the bladder. Techniques will now be described for embodiments in which additional mass is introduced by multiple electronic devices at different locations around the periphery of the bladder.

[0140] Figure 9 shows a ball 1 with a bladder 10 having bladder wall 11 and valve 4, as described above with respect to Figure 1. A first electronic device 2a is provided in a first housing 3a, which is constructed and arranged identically to that described above with respect to Figure 1. Additionally, this ball 1 comprises a second electronic device 2b. The second electronic device 2b is secured in a second housing 3b, which is adhered to an inner surface of the bladder wall. As shown in Figure 10, the position of these two electronic devices has been selected so that they are at two of the four vertices of a regular tetrahedron circumscribed by the sphere of the bladder wall 11. It is assumed here that the electronic devices 2a and 2b have the same mass or that the housings 3a, 3b can be weighted so that the first electronic device 2a and first housing 3a have the same mass as the second electronic device 2b and second housing 3b.

[0141] According to this positioning of the electronic devices 2a, 2b, there are two options for balancing the mass of the electronic devices.

[0142] A first option is to provide two balancing masses at first and second balancing points 111, 112 corresponding to the other two vertices of this regular tetrahedron. This could be a point like balancing mass as described with reference to Figure 2, a patch centred on each balancing point, as described with reference to Figure 7, ora region of integrally formed balancing masses centred on each balancing point, as described with reference to Figure 8.

[0143] As a second option, consider a first point 101, which is the point of the bladder wall 11 that is closest to the combined centre of mass of the two electronic devices2a, and a second point 102 opposite the first point. The distributed balancing mass may be provided by any mass distributed around this second point 102 and closer to the second point than the first point. In Figure 10, a circular track 114 is shown extending around the second point and which also passes through the two balancing points 111, 112 mentioned in connection with the first option of the preceding paragraph, although this is not essential. This circular track 114 defines a plane, such that the first point 101 is perpendicularly offset from the plane from a centre point of the circle, as illustrated by the arrow P. Distributing mass evenly along this circular track 114, and particularly, evenly with respect to the balancing points 111, 112, will substantially allow for both of the criteria set out in equations (1) to (3) above to be met. The mass may be distributed along this track using any of the techniques described above with respect to Figures 3A to 6B, including tracks of integrally formed balancing mass elements or a continuous strip attached on or over the bladder wall 11. Alternatively, four or more balancing mass elements may be arranged along this circle, in line with Figure 2C.

[0144] Finally, Figure 11 shows a ball 1 with a bladder 10 having bladder wall 11 and valve 4, as described above with respect to Figure 1. A first electronic device 2 is provided in a first housing 3, which is constructed and arranged identically to that described above with respect to Figure 1. Additionally, this ball 1 comprises a second electronic device 2’ secured in a second housing 3’, which is adhered to an inner surface of the bladder wall. It is possible to address and balance the masses of these electronic devices separately from one another, essentially ignoring any effect of the other. If we take a ball that has been balanced in accordance with the technique of Figure 2A, for example. This ball now has essentially the same centre of mass and moment of inertia about any axis as a ball without an electronic device and distributed balancing mass. Therefore a second device may be balanced in just the same way as the first. Figure 12 illustrates this.

[0145] In Figure 12, the first electronic device 2 of the ball of Figure 11 defines a first point 101, which is the point on the bladder wall 11 that substantially coincides with the centre of mass of that electronic device. A second point 102 is defined oppositethe first point. The mass of the first electronic device 2 is balanced by a track of integrally formed balancing elements 13 extending along the circumference of a circle defining a cone together with the first point, as described above with respect to Figure 3A. Additionally, the second electronic device 2’ defines a third point 103 on the bladder wall 11 that substantially coincides with the centre of mass of that second electronic device. A fourth point 104 is defined opposite to the third point. Again, that third point may be taken as the first vertex of a regular tetrahedron defined by four points lying in the bladder wall, and then the other three points of that tetrahedron used to describe a circular track around the bladder wall so that another cone is defined, wherein the third point is offset perpendicularly from the plane of this circle from the centre of the circle. This described circular track may be provided with a series of integrally formed balancing mass elements 13’, which collectively form a second distributed balancing mass 12’ in the same way as the first track of balancing mass elements 13 that was defined with respect to the first point.

[0146] Figure 13 illustrates another balancing arrangement that is a variant of the arrangement of Figures 11 and 12. In Figure 13, a first electronic device is located at a first point 101 on the bladder wall 11. It is assumed that the electronic device essentially coincides with this first point. The position also defines a second point 102 opposite the first point and the first electronic device. A second electronic device is located at a third point 103 on the bladder wall. If the first point is considered the first vertex of a regular tetrahedron that is circumscribed by the sphere defined by the bladder wall 11, then the third point corresponds to another one of the four vertices. The position of the second electronic device also defines a fourth point 104 opposite the third point.

[0147] The first electronic device located at the first point 101 is balanced by a first distributed balancing mass 12. The first distributed balancing mass is formed of a track of balancing mass elements 13 along the bladder wall 11. The track of balancing mass elements 13 define the circumference of a circle, which together with the first point define an inscribed cone. The position of the balancing mass elements is defined using the same method as Figure 3A. In particular, the regulartetrahedron circumscribed by the sphere of the bladder wall is found where a first vertex is the first point 101. The circular track of balancing mass elements is thus defined by the plane defined by the other three vertices. Because of this arrangement, the second electronic device at point 103 lies along the track defined by the distributed balancing mass 12.

[0148] The second electronic device located at the third point 103 is balanced by a second distributed balancing mass 12’. The second distributed balancing mass is formed of a track of balancing mass elements 13’ along the bladder wall 11. The track of balancing mass elements 13’ define the circumference of a circle, which together with the third point define an inscribed cone. The position of the balancing mass elements is defined in the same way as for the first electronic device. In particular, the regular tetrahedron circumscribed by the sphere of the bladder wall is found where a first vertex is the third point 103. The circular track of balancing mass elements is thus defined by the plane defined by the other three vertices. Because of this arrangement, the first electronic device at point 101 lies along the track defined by the second distributed balancing mass 12’.

[0149] Figure 14 shows another embodiment for balancing first and second electronic devices 2a, 2b. These two electronic devices are located at two of the four vertices of a regular tetrahedron circumscribed by the sphere of the bladder wall. The other two vertices define first and second balancing points 111, 112. A first point on the bladder wall 101 is the point on the bladder wall 11 closest to the centre of mass of the two electronic devices. If the two electronic devices have the same mass, this point will be equidistant between the two electronic devices 2a, 2b. A second point 102 is defined opposite this first point. The first and second balancing points 111, 112 are positioned around the second point 102, separated by 180° measured about the second point, and the first and second balancing points are closer to the second point 102 than the first point 101. In this embodiment, the distributed balancing mass 12 is formed by a track of small balancing mass elements, the track extending along a line of a great circle that passes through the first and second balancing points 111 , 112 and through the second point 102. The track defines only part of this great circle, in particular the track extends two thirdsof the way around the bladder wall, that two thirds being centred on the second point 102, such that the track may be considered as having two halves, each centred on the first and second balancing points 111, 112. In this case, some balancing mass elements may be provided that are closer to the first point than the second point; however, the ball still comprises some (indeed most) balancing mass elements positioned around the second point and closer to the first point than the second. A longer or shorter track could be used, or two separate shorter tracks could be used, each respectively centred on one of the first and second balancing points, 111, 112.

[0150] While the embodiments of Figures 12 to 14 illustrate tracks of small, spaced balancing mass elements, it should be appreciated that these tracks could also be formed by continuous strips, in the same way as Figure 6A. Alternatively, fewer more massive balancing mass elements could be used, in the case of Figure 12 and 13, down to singular balancing mass elements on the vertices of the or each regular tetrahedron defined with respect to the first point, and third point, if provided.

[0151] Finally, Figures 15A and 15B illustrates the extension of the above principles to prolate spheroid-shaped balls. The ball 1 again comprises a bladder wall 11 defining the inflated shape of the ball. An electronic device 2 is provided. The device is positioned on the inner surface of the bladder wall at a position half way along the length of the ball. The valve 4 is positioned opposite to the electronic device, although because of the present balancing arrangement, this is not essential. In Figure 15A, the position of the electronic device 2 defines a first point 101 that substantially coincides with the position of the electronic device 2 on the bladder wall 11, and defines a second point 102 opposite the first point, i.e. coincident with the valve 4. First, second and third balancing points 111, 112, 113 are defined by vertices of a tetrahedron whose four vertices coincide with the bladder wall and which has a first vertex at the first point 101. The first, second and third balancing points 111, 112, 113 define an ellipse, wherein the first point 101 is perpendicularly offset from a centre point of the ellipse. The first balancing point 111 is located at the vertex of this ellipse. The second balancing point 112is located between the second vertex of the ellipse and a first co-vertex of the ellipse. The third balancing point 112 is located between the second vertex and a second co-vertex of the ellipse opposite to the first co-vertex. The first, second and third balancing points are positioned such that a centre of mass of three identical masses positioned on those balancing points will lie on the axis extending between the first and second points 101 , 102.

[0152] With the above balancing points defined, the mass of the electronic device 2 may be balanced in the prolate spheroid ball 1 by arranging balancing mass elements with respect to these three balancing points. The balancing mass elements could take the form of three essentially point mass elements, analogous to Figure 2A, or could be arranged along tracks along the ellipse analogous to Figures 3A, 4, 5A, or 6. They could also be distributed around the three balancing points analogously to Figures 7A or 8A.

[0153] Figure 15B shows a variant in which four balancing mass elements 13 are provided on four balancing points 111, 112, 113, 114. Consider the same ellipse defined by the tetrahedron described with reference to Figure 15A. The four balancing points 111, 112, 113, 114 of this embodiment are evenly spaced around this ellipse, such that one balancing point is provided between each vertex and co-vertex of the ellipse. Like Figure 2C, this reduces the required mass of each balancing mass element while still attaining satisfactory balancing of the electronic device 101.

[0154] As has been mentioned earlier, the arrangements described above are useful in situations where it may be generally desired for a ball with electronic devices to behave as similarly as possible to one without the electronic devices. In other words, the mass of the valve is not taken into account in any of the above arrangements.

[0155] However, in some scenarios it is preferable to factor in the mass of the valve to achieve a ball whose total centre of mass is substantially at the centre. Figure 16 shows an example arrangement in which the mass of the valve 4 is taken into account.As before, this arrangement uses a distributed balancing mass 12 comprising one or more mass elements 13 to balance the mass of the electronic device 2 and housing 3. In particular, Figure 16 shows a tetrahedral balancing arrangement similar to that of Figure 2A. As before, the tetrahedral balancing arrangement includes four vertices 101, 111, 112, and 113 all of which coincide with the bladder wall 11. Three of the vertices of this regular tetrahedron, i.e. the balancing points, define the preferred locations of three balancing mass elements 13 for offsetting the balance of the electronic device 2 and its housing 3. As can be seen in Figure 16, the valve 4 of the spherical ball is located at one of the vertices of the regular tetrahedron and so in this arrangement one of the balancing mass elements comprises the valve 4.

[0156] In the arrangement shown in Figure 2A, the electronic device 2 and the housing 3 were located at the first vertex in the regular tetrahedron and a straight line could be drawn along the bladder wall passing through the three balancing points 111, 112, 113 to define a circle. However, in Figure 16, the electronic device 2 and the housing 3 are depicted as being along the line that defines a circle around the bladder wall 11 and the first vertex in Figure 16 is depicted as being the valve 4. Since the tetrahedron is regular, the skilled person will appreciate that the orientation of the ball is arbitrary, such that any of the three balancing points 111, 112, 113 can be considered as the “first” vertex. The important consideration is that the valve 4 is located at one of the balancing points 111, 112, 113, and the valve 4 acts as at least part of the balancing mass element 13 at said balancing point.

[0157] By taking the valve 4 into consideration, and including the valve 4 as one of the balancing mass elements 13, fewer additional components need to be added to the spherical ball of Figure 1 to arrive at an arrangement which maintains the rotational balance of the ball so that there are no unbalanced forces or moments when the ball is spinning about any axis. The arrangement of Figure 16 may therefore be cheaper and simpler to manufacture than arrangements which do not factor in the mass of the valve 4.The mass of the valve 4 may be different to at least one of the balancing mass elements 13 at the other vertices of the tetrahedron, for example the valve 4 may be lighter than the other two balancing mass elements 13. In this case, it may be preferable to increase the mass of the valve 4 such that the mass at each of the three balancing points is substantially equal. One way of achieving this is to include a block of rubber in an area substantially next to, and preferably surrounding, the valve 4. As has been described in relation to Figure 2B, the block of rubber is moulded to have the correct size and shape, i.e. suitable for adhering to the concave inner surface of the bladder wall 11 , and is adhered to the inside of the bladder wall 11 by an adhesive. Any suitable method for increasing the mass at the balancing point at which the valve is located can be used, and any suitable method for attaching mass-increasing components, such as a block of rubber, to the bladder wall 11 can be used. In this example, even though the mass at the balancing point at which the valve 4 is located has been increased, the overall mass of the resulting arrangement will typically still be lighter than previously described arrangements (for example the arrangement in Figure 2A), because the valve itself is not an additional mass but instead has been accounted for.

[0158] Although the valve has been described as being incorporated into the regular tetrahedron arrangement of Figure 2A, it will be appreciated that the valve can be incorporated in any suitable balancing point in any of the previously described arrangements. That is, the valve is not only compatible with a regular tetrahedron arrangement of balancing points. For example, the valve could be suitably incorporated into at least any of Figures 3A-15B.

[0159] Figures 17 to 20 illustrate balancing mass elements 14 that may be attached on or over the bladder wall 11 wherein the balancing mass elements 14 comprise a plurality of sub-masses 142 that are interconnected by one or more interconnecting portions 144, such that the plurality of sub-masses 142 may move relative to one another during deformation of the bladder wall 11 by stretching or bending of the interconnecting portions 144.

[0160] Such embodiments, where a plurality of sub-masses 142 that are interconnected by one or more interconnecting portions 144 are used, are particularly applicableto the embodiments discussed in combination with Figures 2A to 2C, 15Aand 15B, and 16, in which one or more balancing masses are localised at discrete balancing points.

[0161] Figure 17 illustrates an inflatable ball similar to the one depicted in Figure 2Aand therefore shows a tetrahedral balancing arrangement of the spherical ball shown in Figure 1. In this example, the centre of mass of the electronic device 2 and the housing 3 is substantially coincident with the first point 101 on the bladder, which in the Figure is the uppermost point of the bladder wall 11. Opposite the first point 101 is a second point 102. The first point 101 is treated as the first vertex in a regular tetrahedron whose other three vertices 111, 112, 113 also coincide with the bladder wall 11. In other words, the regular tetrahedron that is circumscribed by the sphere of the bladder wall. The other three vertices of this regular tetrahedron, which are referred to herein as balancing points, define the preferred locations of three balancing masses for offsetting the balance of the electronic device 2 and its housing 3. As shown in Figure 17, a straight line along the bladder wall passing through these three balancing points 111, 112, 113 defines a circle. The first and second points 101 , 102 are both perpendicularly offset from the plane of this circle from the centre point of this circle. This plane, and all three balancing points 111, 112, 113 are closer to the second point 102 than the first point 101.

[0162] However, in the example illustrated by Figure 17, the one or more balancing mass elements 14 comprise a plurality of sub-masses 142 that are interconnected by one or more interconnecting portions 144.

[0163] Figures 18 to 20 illustrate exemplary forms that the one or more balancing mass elements 14 comprising a plurality of sub-masses 142 that are interconnected by one or more interconnecting portions 14 may take.

[0164] Figure 18A illustrates a balancing mass element 14 comprising a plurality of submasses 142, while Figure 18B depicts a cross-section “G-G” of the balancing mass element 14 depicted in Figure 18A.As is illustrated by Figure 18a, the balancing mass element 14 comprises a plurality of sub-masses 142 that are connected via one or more interconnecting portions 144.

[0165] This may produce, as is the case in Figure 18A, an overall circular balancing mass element 14 due to the regular and repeating pattern of sub-masses 142 within a defined circumference and more interconnecting portions 144; however, this is not essential. For example, the outer sub-masses 142 may not be cut-off and therefore the overall shape produced will be one with square protrusions. Many other shapes are possible, and are not limited to circles or squares.

[0166] As can be seen from Figure 18B, the plurality of sub-masses 142 are connected to a neighbouring sub-mass via a relatively thin interconnecting portion 144. The interconnecting portions 144 may form a base 146 for attaching the one or more balancing mass elements 14 to the bladder wall 11.

[0167] As also can be seen from Figure 18B, the sub-masses 142 can protrude outwards substantially in parallel and away from a base. However, the sub-masses 142 can protrude outwards but not in parallel, and may not have a base. For example, the interconnecting portions may be located in the centre of the balancing mass elements along the direction perpendicular to the bladder wall.

[0168] While in Figures 18Aand 18B, as well as in Figures 19 and 20 to a lesser degree, the sub-masses 142 are very close to one another and therefore have quite small interconnecting portions 144, this disclosure does not limit to this. For example, the sub-masses 142 can be more spread apart and thereby have interconnecting portions 144 which are larger. In such situations, preferably the interconnecting portions 144 have a length perpendicular to the sub-mass 142 which is greater than a the greatest dimension of the sub-mass 142.

[0169] The use of sub-masses 142 for the one or more balancing mass elements 13 results in avoidance of the one or more balancing mass elements 13 distorting the overall shape of the bladder. This is because, if the one or more balancing mass elements 13 are comprised of a single block or section of material, then this willresult in a local change of shape in the inflatable ball once inflated, therefore creating a departure from the overall intended shape of the ball. The local change in shape is a result of the bladder being unable to deform and change shape as it would normally, as the single block or section of material which creates the balancing mass element constricts the amount to which the bladder can expand relative to sections of the bladder without such balancing mass elements.

[0170] The sub-masses 142 address the above discussed issue by being able to move and bend relative to one another via the flexible interconnecting portions 144, thereby allowing the one or more balancing mass elements 13 to stretch and bend to allow the bladder to deform as it inflates in a usual manner. This allows the ball to maintain its overall intended shape once inflated.

[0171] Furthermore, the sub-masses 142 and interconnecting portions 144 allows the ball to behave more normally when bounced or kicked as the coefficient of restitution of the ball is impacted less by sub-masses 142 than a single large mass. This is because the sub-masses 142 present much less resistance to deformation as they are able to bend, flex, and generally deform relative to one another. Therefore, when a player is using the ball, it will behave as would be expected of a ball without internal devices when being bounced or kicked as it is able to flex and bend substantially as would be expected.

[0172] In some embodiments, the interconnecting portions 144 may be provided with sufficient thinness that they tear or separate during inflation of the ball, and indeed this may be desirable. The interconnecting portions allow the sub-masses 142 to be applied to the bladder wall in one step, e.g. be adhering the base of the balancing mass element to the bladder wall. After this, tearing or separating of the interconnecting portionswill not impact the performance of the balancing mass element, and indeed may help the sub-masses to move freely relative to one another.

[0173] The sub-masses 142 do not need to be added to the inside of the bladder wall 11, as they could also be added to the outside of the bladder wall 11 , or to the inside panels which surround the bladder. However, this would necessitate much thinnersub-masses, leading to a balancing mass element that is more spread out, and so is less preferred.

[0174] Therefore, the provision of sub-masses 142 allows for one or more balancing mass elements which are more compliant, thereby improving the sphericity and coefficient of restitution of the ball while still providing a rotationally balanced inflatable ball comprising electronics.

[0175] Figure 19 illustrates a balancing mass element comprising a plurality of submasses wherein the plurality of sub-masses are circular in cross-section, and the balancing mass element forms an overall circular shape.

[0176] As can be seen, the plurality of sub-masses 142 in Figure 19 are formed of circular masses 142 and are arranged in a repeating radial arrangement, wherein each sub-mass is radial relative to one of the sub-masses in the centre of the balancing mass element 14.

[0177] Similar to Figure 18A, it can be seen that in this example that the balancing mass elements 14 has a broadly circular shape, but this is not required. Preferably, the overall shape of the balancing mass elements 14 results in a centre of mass that is coincident with points 111 , 112, and 113.

[0178] Figure 20 illustrates a balancing mass element comprising a plurality of submasses wherein the plurality of sub-masses are square in cross-section, similar to the example shown in Figures 18A and 18B, and the balancing mass element forms an overall square shape.

[0179] Once again, it should be stressed that the overall shape does not need to be a square, or a circle, but preferably the overall shape of the balancing mass elements 14 results in a centre of mass that is coincident with points 111, 112, and 113.

[0180] The one or more balancing mass elements 14 comprising a plurality of submasses 142 that are interconnected by one or more interconnecting portions 144 may be manufactured by cutting, etching, or otherwise removing material from, asolid block of material. Therefore, the portions of material left between submasses 142 form the one or more interconnecting portions 14.

[0181] Alternatively, the one or more balancing mass elements 14 comprising a plurality of sub-masses 142 that are interconnected by one or more interconnecting portions 14 may be manufactured by moulding the balancing mass element or via additive manufacturing, such as via 3D printing.

[0182] The one or more balancing mass elements 14 comprising a plurality of submasses 142 that are interconnected by one or more interconnecting portions 14 may be attached to the bladder via adhesive bonding, or welding such as polymer welding.

[0183] Turning to another aspect of the current disclosure, the inflatable ball may comprise an air permeable compartment for attaching electronic devices to the inflatable ball.

[0184] This synergistically combines with the above disclosures relating to rotational balancing as it further aids in creating an inflatable ball comprising electronics that behaves as a ball without electronics.

[0185] Furthermore, this embodiment is synergistically combines with the sub-masses embodiment because it further reduces the likelihood of a misshapen ball and allows for easier rotational balancing while maintaining a low overall mass.

[0186] As can be seen in Figures 21 and 22, the electronics casing 3 includes an electronics casing base 170 and sealing member 11. The electronics casing base 170 has a recessed or concave compartment 80 with a substantially square footprint. The compartment 80 is recessed with respect to a circular flange portion 130 of the electronics casing base 170. The compartment 80 defined by the electronics casing 3 has at least one electronic component 2 and may additionally comprise shock absorbing layer located inside.The bladder, as is usual in an inflatable ball, defines the inflatable interior 100 of the ball. The bladder and electronic casing are attached to one another in such a manner as to create an airtight inflatable ball.

[0187] Figure 21 depicts an electronics casing as used in this embodiment, wherein the electronics casing is formed of an electronics casing base 170 and a sealing member 11. The sealing member 11 is the inner surface of the bladder 11 , as the electronics casing base 170 is attached directly to the inner surface of the bladder 11. However, it is envisioned that a separate sealing member other than the bladder could also be provided. As can be seen, Figure 21 provides a simplified schematic which portrays general relationships between components and features, and does not prescribe specific geometries or relative sizes.

[0188] The bottom of the electronics case base 180 preferably contains perforations 60 such that the compartment 80 is in fluid communication with the inflatable interior of the ball. As the compartment 80 and the inflatable interior of the ball 100 are in fluid communication they are at the same pressure.

[0189] Therefore, a compartment, for at least one electronic component, in an inflatable ball is at the same pressure as the inflatable interior of the ball while still providing a ball which can be inflated.

[0190] An additional preferable feature of the first embodiment is the addition of a shock absorbing layer 40 between the at least one electronic component 2 and the outside of the inflatable ball. The shock absorbing layer may be a layer of foam padding, for example.

[0191] The shock absorbing layer 40 provides protection to the at least one electronic component 2 while the inflatable ball is in use. For example, when being hit or kicked, the ball experiences great levels of forces during the action as well as when the ball lands or is hit or kicked again. The shock absorbing layer 40 reduces the magnitude of the force experienced by the at least one electronic component 2 within the inflatable ball. As the greatest sudden force which may be imparted on the inflatable ball will likely be from the direction of the exterior of the inflatableball, and therefore the bladder as well, the shock absorbing layer is placed between the electronic component and an exterior of the bladder.

[0192] The shock absorbing layer 40 substantially surrounds the at least one electronic component 2 on all but one side, and the side of the electronics 2 not surrounded by the shock absorbing layer 40 faces towards a centre of the inflatable interior 100 defined by the bladder 10.

[0193] As is clear from the above, in this embodiment, the electronics casing is fixed relative to the bladder and therefore cannot move relative to it once attached. The electronic component 2 may be fixed to the compartment 80, e.g. by an adhesive, or as shown in this embodiment may be restrained by the shock absorbing material so that it is securely held while the inflatable ball while it is in use.

[0194] The above embodiment is suitable for inflatable balls to be used as a rugby ball, an American football, or a soccer ball, for example.

[0195] Figure 22 depicts a cut through of a section of the inflatable ball, while also providing an overall view of the inflatable ball, such that the majority of the features which are relevant can be seen.

[0196] In particular, the casing base 170 comprises a recessed or concave compartment 80 with a substantially square footprint. The compartment 80 is recessed with respect to a circular flange portion 130 of the electronics casing base 170. The electronics casing base 170 is attached to the inner surface of the bladder 90, e.g. by the upper surface 140 of the flange 130. In this case, the role of the sealing member is again carried out by the inner surface of the bladder 90 to which the casing is attached.

[0197] As an additional benefit, reduction in weight due to the perforations aids in creating rotational balance as the weight of the device, which causes the rotational imbalance and which is attempting to be reduced, is reduced. Therefore, preferably, the electronics case base 180 contains 4 or more perforations 60, or 8 or more perforations, or 16 or more perforations. Preferably, the electronics case base 180 contains a plurality of perforations 60 arranged in a lattice or regularpattern such that the weight is reduced, while still being capable of retaining the electronic components 3.

[0198] The invention may also be understood with reference to the following numbered clauses:

[0199] Clause 1: An inflatable ball comprising: a bladder having a bladder wall defining an inflatable interior of the ball; at least one device mounted on or over the bladder wall such that a centre of mass of the at least one device is located away from a centre of the inflatable interior of the ball, the at least one device including at least one electronic device, the centre of mass of the at least one device defining a first point on the bladder wall coincident with or closest to the centre of mass of the at least one device and a second point on the bladder wall opposite the first point; and a distributed balancing mass for at least partially rotationally balancing the mass of the at least one device, the distributed balancing mass comprising one or more balancing mass elements on or over the bladder wall, the one or more balancing mass elements being arranged at a plurality of locations spaced around the second point on the bladder wall and closer to the second point than the first point; wherein one of the one or more balancing mass elements comprises a valve of the inflatable ball.

[0200] Clause 2: The inflatable ball according to clause 1, wherein the valve accounts for all the mass of one of the balancing mass elements at its respective location.

[0201] Clause 3: The inflatable ball according to clause 1, wherein the valve accounts for part of the mass of one of the balancing mass elements at its respective location.

[0202] Clause 4: The inflatable ball according to clause 3, wherein the balancing mass comprising the valve further comprises an additional mass element.

[0203] Clause 5: The inflatable ball according to clause 4, wherein the additional mass element comprises a block of rubber.

[0204] Clause 6: The inflatable ball according to clause 1, wherein the distributed balancing mass comprises one of: at least four balancing mass elements one ofwhich is the valve, the balancing mass elements being arranged substantially at, or substantially evenly distributed by mass, with respect to each of at least four balancing points equally spaced around the second point and closer to the second point than the first point; or one or more mass balancing elements arranged on or over the bladder wall along one or more tracks along the bladder wall defining substantially all or one or more parts of the circumference of a circle or an ellipse.

[0205] Clause 7: The inflatable ball according to clause 1, wherein the one or more balancing mass elements arranged on or over the bladder wall along one or more tracks along the bladder wall comprises one or more balancing mass elements arranged substantially evenly distributed by mass with respect to each of at least three balancing points spaced around the second point, the three balancing points together with the first point and / or the centre of mass of the of the at least one device defining four vertices of a substantially regular tetrahedron.

[0206] Clause 8: The inflatable ball according to any of the preceding clauses, wherein the first point and the distributed balancing mass define a cone shape, the first point defining the tip of the cone and the distributed balancing mass extending around the base of the cone.

[0207] Clause 9: The inflatable ball according to any of the preceding clauses, wherein the distributed balancing mass comprises at least five balancing mass elements arranged substantially at, or substantially evenly distributed by mass, with respect to five balancing points equally spaced around the second point, preferably at least eight balancing mass elements arranged substantially at, or substantially evenly distributed by mass, with respect to eight balancing points equally spaced around the second point, most preferably at least ten balancing mass elements arranged substantially at, or substantially evenly distributed by mass, with respect to ten balancing points equally spaced around the second point.

[0208] Clause 10: The inflatable ball according to any of the preceding clauses, wherein the one or more mass balancing elements are arranged on or over the bladder wall along one or more tracks along the bladder wall defining substantially all or one or more parts of the circumference of a circle or an ellipse and wherein thefirst point lies perpendicular to the plane of the circle or the ellipse from the centre of the circle or the ellipse.

[0209] Clause 11: The inflatable ball according to any of the preceding clauses, wherein the one or more mass balancing elements are arranged on or over the bladder wall along one or more tracks along the bladder wall defining substantially all or one or more parts of the circumference of a circle or an ellipse and wherein the at least one device comprises a first device and a second device, wherein the one or more tracks along the bladder wall pass through first and second balancing points spaced around the second point and define part(s) of the circumference of a circle or an ellipse passing between the first and second devices.

[0210] Clause 12: The inflatable ball according to any of the preceding clauses, wherein the one or more mass balancing elements are arranged on or over the bladder wall along one or more tracks along the bladder wall defining substantially all or one or more parts of the circumference of a circle or an ellipse and wherein the one or more tracks extend along at least 50% of the circumference of the circle or ellipse, preferably at least 60%, more preferably at least 70%, more preferably at least 80%, most preferably wherein the wherein the one or more tracks extend along substantially the whole of the circumference of the circle or ellipse.

[0211] Clause 13: The inflatable ball according to any of the preceding clauses, wherein the one or more balancing mass elements comprises one or more continuous strips, preferably adhesive strips, attached on or over the bladder wall.

[0212] Clause 14: The inflatable ball according to clause 13, wherein each continuous strip is attached on an inner surface of the bladder wall.

[0213] Clause 15: The inflatable ball according to clause 13, wherein each continuous strip is attached on an outer surface of the bladder wall.

[0214] Clause 16: The inflatable ball according to clause 13, wherein each continuous strip is provided in or attached to a cover of the inflatable ball, the cover surrounding the bladder.Clause 17: The inflatable ball according to any of clauses 13 to clause 16, wherein each continuous strip comprises a plurality of increased thickness portions of the strip separated by reduced thickness portions of the strip.

[0215] Clause 18: The inflatable ball according to clause 17, wherein each increased thickness portion has a largest dimension along the length of the continuous strip of no more than 4 cm, preferably no more than 2 cm, more preferably no more than 1 cm.

[0216] Clause 19: The inflatable ball according to clause 17 or clause 18, wherein the thickness of the increased thickness portions of the continuous strip is at least twice the thickness of the thinnest part of the continuous strip, preferably at least three times the thickness of the thinnest part of the continuous strip, more preferably at least four times the thickness of the thinnest part of the continuous strip.

[0217] Clause 20: The inflatable ball according to any of clauses 13 to 19, wherein opposing ends of each continuous strip define complementary non-linear or obliquely angled end edges such that opposing end edges of one or more continuous strips may be aligned to one another by the complementary end edges.

[0218] Clause 21: The inflatable ball according to any of clauses 13 to 20, wherein each continuous strip has a length along the surface of the bladder at least twice as long as a width along the bladder wall, more preferably at least three times as long, more preferably at least five times as long, most preferably at least ten times as long as the width along the bladder wall.

[0219] Clause 22: The inflatable ball according to any of the preceding clauses, wherein the one or more balancing mass elements comprises one or more balancing mass elements formed integrally with the bladder wall.

[0220] Clause 23: The inflatable ball according to clause 22, comprising a plurality of balancing mass elements formed integrally with the bladder wall by increased wall-thickness portions of the bladder wall.Clause 24: The inflatable ball according to clause 23, wherein each increased wall-thickness portion has at least one lateral dimension of no more than 2 cm, preferably no more than 1 cm, more preferably no more than 0.5 cm.

[0221] Clause 25: The inflatable ball according to clause 24, wherein each increased wall-thickness portion has a largest lateral dimension of no more than 2 cm, preferably no more than 1 cm, more preferably no more than 0.5 cm.

[0222] Clause 26: The inflatable ball according to any of clauses 23 to 25, wherein each increased wall-thickness portion of the bladder wall is surrounded by a portion not having the increased wall thickness.

[0223] Clause 27: The inflatable ball according to any of clauses 23 to 26, wherein each increased wall-thickness portion projects from an inner surface of the bladder wall towards the centre of the inflatable interior of the ball.

[0224] Clause 28: The inflatable ball according to any of clauses 23 to 27, wherein the wall thickness of the increased wall-thickness portions is no more than five times the wall thickness of the thinnest part of the bladder wall, preferably no more than four times the thickness, even more preferably no more than three times the thickness, most preferably no more than twice the thickness of the thinnest part of the bladder wall.

[0225] Clause 29: The inflatable ball according to any of the preceding clauses, wherein the at least one device balanced by the distributed balancing mass is mounted at a substantially single point on or over the bladder wall.

[0226] Clause 30: The inflatable ball according to any of the preceding clauses, wherein the bladder defines a substantially spherical inflatable interior of the ball.

[0227] Clause 31: The inflatable ball according to any of the preceding clauses, wherein the inflatable ball is an inflatable sports ball, preferably a soccer ball, basketball, netball, volleyball, or handball.Clause 32: A method of manufacturing an inflatable ball, the method comprising: providing a bladder having a bladder wall defining an inflatable interior of the ball; providing at least one device mounted on or over the bladder wall such that a centre of mass of the at least one device is located away from a centre of the inflatable interior of the ball, the at least one device including at least one electronic device, the centre of mass of the at least one device defining a first point on the bladder wall coincident with or closest to the centre of mass of the at least one device and a second point on the bladder wall opposite the first point; and providing a distributed balancing mass for at least partially rotationally balancing the mass of the at least one device, the distributed balancing mass comprising one or more balancing mass elements provided on or over the bladder wall, the one or more balancing mass elements being arranged at a plurality of locations spaced around the second point on the bladder wall and closer to the second point than the first point; wherein one of the one or more balancing mass elements comprises a valve of the inflatable ball.

[0228] Clause 33: The method according to clause 32, wherein providing the distributed balancing mass comprises attaching one or more continuous strips, preferably adhesive strips, on or over the bladder wall.

[0229] Clause 34: The method according to clause 33, wherein providing the distributed balancing mass comprises incorporating or attaching the attaching the distributed balancing mass in or on a cover of the inflatable ball and arranging the cover to surround the bladder.

[0230] Clause 35: The method according to any of clauses 32 to 34, wherein providing the bladder comprises moulding the bladder, and wherein providing the distributed balancing mass comprises moulding one or more balancing mass elements integrally with the bladder wall when moulding the bladder.

[0231] Clause 36: The method according to clause 35, wherein moulding one or more balancing mass elements integrally with the bladder wall when moulding the bladder comprises moulding a plurality of increased wall-thickness portions of the bladder wall.Clause 37: The method according to any of clauses 32 to 36, adapted to manufacture an inflatable ball according to any of clauses 1 to 31.

Claims

62CLAIMS1. An inflatable ball comprising:a bladder having a bladder wall defining an inflatable interior of the ball; at least one device mounted on or over the bladder wall such that a centre of mass of the at least one device is located away from a centre of the inflatable interior of the ball, the at least one device including at least one electronic device, the centre of mass of the at least one device defining a first point on the bladder wall coincident with or closest to the centre of mass of the at least one device and a second point on the bladder wall opposite the first point; anda distributed balancing mass for at least partially rotationally balancing the mass of the at least one device, the distributed balancing mass comprising one or more balancing mass elements on or over the bladder wall, the one or more balancing mass elements being arranged at a plurality of locations spaced around the second point on the bladder wall and closer to the second point than the first point;wherein one of the one or more balancing mass elements comprises a valve of the inflatable ball; and / orwherein one of the one or more balancing mass elements is attached on or over the bladder wall and comprises a plurality of sub-masses that are interconnected by one or more interconnecting portions, such that the plurality of sub-masses may move relative to one another during deformation of the bladder wall by stretching or bending of the interconnecting portions.

2. The inflatable ball according to claim 1 , wherein the valve accounts for all the mass of one of the balancing mass elements at its respective location.

3. The inflatable ball according to claim 1, wherein the valve accounts for part of the mass of one of the balancing mass elements at its respective location, and preferably the balancing mass comprising the valve further comprises an additional mass element.

4. The inflatable ball according to any preceding claim when one of the one or more balancing mass elements comprises the plurality of sub-masses, wherein63the plurality of sub-masses are arranged in a regular or irregular two-dimensional distribution of sub-masses, such that the plurality of sub-masses may move relative to one another along each of at least two substantially orthogonal directions during deformation of the bladder wall by stretching or bending of the interconnecting portions.

5. The inflatable ball according to claim 4, wherein one or more of the plurality of sub-masses are square, rectangular, circular, triangular, or oval in a cross-section parallel to the interconnecting portions.

6. The inflatable ball according to claim 5, wherein one or more of the plurality of sub-masses have a constant cross-section in a direction perpendicular to the interconnecting portions.

7. The inflatable ball according to claim 5, wherein one or more of the plurality of sub-masses have a non-constant cross-section in a direction perpendicular to the interconnecting portions.

8. The inflatable ball according to any preceding claim when one of the one or more balancing mass elements comprises the plurality of sub-masses, where the balancing mass element comprising the plurality of sub-masses is attached on or over the bladder wall using an adhesive or welding.

9. The inflatable ball according to any preceding claim when one of the one or more balancing mass elements comprises the plurality of sub-masses, wherein the interconnecting portions are part of a base of the balancing mass element, the balancing mass element being attached on or over the bladder wall via the base.

10. The inflatable ball according to any preceding claim when one of the one or more balancing mass elements comprises the plurality of sub-masses, wherein the sub-masses and the interconnecting portions are formed of rubber.

11. The inflatable ball according to any preceding claim when one of the one or more balancing mass elements comprises the plurality of sub-masses, wherein the sub-masses and the interconnecting portions are integrally formed.6412. The inflatable ball according to any preceding claim when one of the one or more balancing mass elements comprises a plurality of sub-masses, wherein the interconnecting portions are formed of a material having a Young’s modulus not more than 50%, or 20%, or 10%, higher than the Young’s modulus of the material forming the bladder wall, preferably equal to or lower than the Young’s modulus of the material forming the bladder wall.

13. The inflatable ball according to any preceding claim, wherein the bladder wall is between 0.0001 m and 0.01 m thick when the bladder is in an uninflated state.

14. The inflatable ball according to any preceding claim when one of the one or more balancing mass elements comprises a plurality of sub-masses, wherein the or each balancing mass element comprises 4 or more sub-masses, or 8 or more sub-masses, or preferably 16 or more sub-masses.

15. The inflatable ball according to any preceding claim when one of the one or more balancing mass elements comprises a plurality of sub-masses, wherein the largest dimension of the balancing mass element is no more than 0.1 m, and preferably no more than 0.05 m.

16. The inflatable ball according to any preceding claim when one of the one or more balancing mass elements comprises a plurality of sub-masses, wherein the interconnected portions are no more than 0.005 m thick, and preferably no more than 0.0025 m thick.

17. The inflatable ball according to any preceding claim when one of the one or more balancing mass elements comprises a plurality of sub-masses, wherein the surface of the balancing mass element which attaches to the bladder has a surface area no greater than 0.01 m2, preferably no greater than 0.0025 m2.

18. The inflatable ball according to any preceding claim, wherein the one or more balancing mass elements comprises one or more balancing mass elements arranged substantially at or substantially evenly distributed by mass with respect to each of at least three balancing points spaced around the second point, the65three balancing points together with the first point and / or the centre of mass of the of the at least one device defining four vertices of a tetrahedron, preferably a substantially regular tetrahedron.

19. The inflatable ball according to any of the preceding claims, wherein the device comprises:an electronics casing attached to, or integrally formed with, the bladder, the electronics casing defining a compartment adjacent an inner surface of the inflatable interior of the ball and sealed within the inflatable interior of the ball; wherein the at least one electronic device is located within the compartment of the electronics casing; and whereinthe electronics casing comprises one or more perforations through the electronics casing so that the compartment of the casing is in fluid communication with the inflatable interior of the ball.

20. The inflatable ball according to claim 19, wherein the electronics casing comprises an opening into the compartment for inserting the at least one electronic component, wherein the opening preferably faces an exterior of the bladder and is closed by an inner surface of the bladder the electronics casing is attached to the bladder about the periphery of the opening.

21. The inflatable ball according to claim 20, wherein the electronics casing is attached to the bladder about the periphery of the opening, preferably via a flange of the electronics casing.

22. The inflatable ball according to any of claims 19 to 21, wherein the electronics casing defines the compartment by a substantially concave portion of the electronics casing.

23. A method of manufacturing an inflatable ball, the method comprising: providing a bladder having a bladder wall defining an inflatable interior of the ball;providing at least one device mounted on or over the bladder wall such that a centre of mass of the at least one device is located away from a centre of the inflatable interior of the ball, the at least one device including at least one66electronic device, the centre of mass of the at least one device defining a first point on the bladder wall coincident with or closest to the centre of mass of the at least one device and a second point on the bladder wall opposite the first point; and providing a distributed balancing mass for at least partially rotationally balancing the mass of the at least one device, the distributed balancing mass comprising one or more balancing mass elements provided on or over the bladder wall, the one or more balancing mass elements being arranged at a plurality of locations spaced around the second point on the bladder wall and closer to the second point than the first point;wherein one of the one or more balancing mass elements comprises a valve of the inflatable ball; and / orwherein one of the one or more balancing mass elements is attached on or over the bladder wall and comprises a plurality of sub-masses that are interconnected by one or more interconnecting portions, such that the plurality of sub-masses may move relative to one another during deformation of the bladder wall by stretching or bending of the interconnecting portions.

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