Abstract
At least one device is mounted on or over the bladder wall of an inflatable ball such that a center of mass of the device is located away from a center of the inflatable interior of the ball. The device includes an electronic device. The center of mass of the device defines a first point on the bladder wall coincident with or closest to the center of mass of the 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 device. The distributed balancing mass comprises one or more balancing mass elements on or over the bladder wall. The 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.
Claims
1.-36. (canceled)
37. 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, wherein the distributed balancing mass is arranged with respect to at least three balancing points that are spaced around the second point and closer to the second point than the first point, wherein the distributed balancing mass comprises, for each balancing point, a set of balancing mass elements or set of balancing mass element increased-thickness portions on or over the bladder wall and evenly distributed by mass with respect to said balancing point such that the centre of mass of the set of balancing mass elements or set of balancing mass element increased-thickness portions substantially coincides with the balancing point or 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 or set of balancing mass element increased-thickness portions.
38. An inflatable ball according to claim 37, wherein the three balancing points together with the first point and/or the centre of mass of the of the at least one device define four vertices of a substantially regular tetrahedron.
39. An inflatable ball according to claim 37, wherein the distributed balancing mass has a total mass of between 2 times and 4 times the mass of the at least one device.
40. An inflatable ball according to claim 37, wherein the one or more balancing mass elements comprises one or more continuous strips or patches attached on or over the bladder wall.
41. An inflatable ball according to claim 37, wherein the one or more balancing mass elements comprises one or more balancing mass elements formed integrally with the bladder wall.
42. An inflatable ball according to claim 41, comprising a plurality of balancing mass elements formed integrally with the bladder wall by increased wall-thickness portions of the bladder wall.
43. An inflatable ball according to claim 37, 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.
44. An inflatable ball according to claim 37, wherein each of the at least one electronic device comprises 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.
45. An inflatable ball according to claim 37, comprising a pocket-like recess into which each of the at least one electronic device is inserted, the pocket-like recess being moulded into the bladder wall or arranged in an opening through the bladder wall.
46. An inflatable ball according to claim 37, wherein the bladder defines a substantially spherical inflatable interior of the ball.
47. 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 the distributed balancing mass comprises 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, wherein the one or more 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, and wherein each track comprises a continuous strip attached on or over the bladder wall or a series of at least five balancing mass elements arranged in a line in which each balancing mass element is spaced from a next balancing mass element within the same track by no more than 5 cm.
48. An inflatable ball according to claim 47, wherein the one or more mass balancing elements arranged on or over the bladder wall along one or more tracks comprise one or more continuous strips attached on or over the bladder wall and wherein each continuous strip comprises a plurality of increased thickness portions of the strip separated by reduced thickness portions of the strip.
49. An inflatable ball according to claim 47, wherein the first point and the one or more mass balancing elements arranged along one or more tracks define a cone shape, the first point defining the tip of the cone and the one or more mass balancing elements arranged along one or more tracks extending around the base of the cone.
50. An inflatable ball according to claim 47, wherein the distributed balancing mass has a total mass of between 2 times and 4 times the mass of the at least one device.
51. An inflatable ball according to claim 47, wherein the one or more tracks extend along at least 50% of the circumference of the circle or ellipse.
52. An inflatable ball according to claim 47, comprising at least three separate tracks.
53. 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 or more of the balancing mass elements comprises a balancing mass element attached on or over the bladder wall, the balancing mass element comprising a plurality of increased-thickness portions separated by reduced-thickness portions.
54. An inflatable ball according to claim 53, wherein each increased-thickness portion has a largest dimension of no more than 4 cm.
55. An inflatable ball according to claim 53, wherein each increased-thickness portion has a thickness at least twice the thickness of the thinnest part of the balancing mass element.
56. An inflatable ball according to claim 53, wherein each reduced-thickness portion has a thickness of no more than 0.5 cm.
57. An inflatable ball according to claim 53, wherein the balancing mass element is a continuous strip.
58. An inflatable ball according to claim 53, wherein the balancing mass element is an adhesive strip or patch.
59. 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 the first point and the distributed balancing mass define a cone shape, the first point defining the tip of the cone and the one or more balancing mass elements being substantially evenly distributed by mass around the base of the cone, wherein the one or more balancing mass elements comprises at least four balancing mass elements 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.
60. An inflatable ball according to claim 59, wherein the distributed balancing mass has a total mass of between 2 times and 4 times the mass of the at least one device.
61. An inflatable ball according to claim 59, wherein the one or more balancing mass elements comprises at least six balancing mass elements provided in the range more than 50% and less than 95% of the distance along the bladder wall from the first point to the second point.
Description
BRIEF DESCRIPTION OF DRAWINGS
[0044] The invention will now be discussed with reference to the accompanying drawings, of which:
[0045] FIG. 1 is a schematic cross-section of a first example of an inflatable ball;
[0046] FIG. 2A schematically illustrates a balancing arrangement for the inflatable ball of FIG. 1, FIG. 2B is an enlarged view of the distributed balancing mass in region A, and FIG. 2C illustrates a variant balancing arrangement;
[0047] FIG. 3A schematically illustrates another balancing arrangement for the inflatable ball of FIG. 1, and FIGS. 3B and 3C are an enlarged views of the distributed balancing mass in region B;
[0048] FIG. 4 schematically illustrates another balancing arrangement for the inflatable ball of FIG. 1;
[0049] FIG. 5A schematically illustrates another balancing arrangement for the inflatable ball of FIG. 1 and FIG. 5B is an enlarged view of the distributed balancing mass in region C;
[0050] FIG. 6A schematically illustrates another balancing arrangement for the inflatable ball of FIG. 1, FIG. 6B is an enlarged view of a first variant of the distributed balancing mass in region D, FIG. 6C is an enlarged view of a second variant of the distributed balancing mass in region D, FIG. 6D is an enlarged view of a third variant of the distributed balancing mass in region D, and FIG. 6E is a schematic view of the distributed balancing mass used in FIGS. 6C and 6D;
[0051] FIG. 7A schematically illustrates another balancing arrangement for the inflatable ball of FIG. 1 and FIG. 7B is an enlarged view of the distributed balancing mass in region E;
[0052] FIG. 8A schematically illustrates another balancing arrangement for the inflatable ball of FIG. 1 and FIG. 8B is an enlarged view of the distributed balancing mass in region F;
[0053] FIG. 9 is a schematic cross-section of a second example of an inflatable ball;
[0054] FIG. 10 schematically illustrates a balancing arrangement for the inflatable ball of FIG. 9;
[0055] FIG. 11 is a schematic cross-section of a third example of an inflatable ball;
[0056] FIG. 12 schematically illustrates a balancing arrangement for the inflatable of FIG. 11;
[0057] FIG. 13 schematically illustrates a balancing arrangement for another inflatable ball;
[0058] FIG. 14 schematically illustrates a balancing arrangement for another inflatable ball; and
[0059] FIGS. 15A and 15B schematically illustrate two different balancing arrangements for another inflatable ball.
DETAILED DESCRIPTION
[0060] FIG. 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.
[0061] As will now be described with respect to FIGS. 2A to 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.
[0062] 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.
[0063] 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 ith mass have position vector {right arrow over (P)}.sub.i and mass m.sub.i. 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 the ball's original centre of mass. By the earlier statement this must be the origin, therefore:
[00001]
[0064] 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:
[00002]
[0065] It can be shown there will be no unbalanced moments if the second term in Equation (2) satisfies the following condition:
[00003]
[0066] 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.
[0067] 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.
[0068] 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 the fewest masses by using a tetrahedral balancing method, which is demonstrated in FIGS. 2A and 2B.
[0069] FIG. 2A shows a tetrahedral balancing arrangement of the spherical ball shown in FIG. 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 FIG. 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 that the first point 101.
[0070] The balancing masses located at the three balancing points 111, 112, 113 are collectively referred to as a distributed balancing mass 12. FIG. 2B shows an enlarged region A of FIG. 2A in cross-section and illustrates one balancing mass element 13 of the distributed balancing mass 12. FIG. 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 and 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 pressed together 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 FIG. 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 since it is 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.
[0071] 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 FIG. 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 FIG. 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 FIG. 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.
[0072] 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 FIGS. 3A to 8B.
[0073] FIG. 3A illustrates an alternative balancing arrangement for balancing the ball of FIG. 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. FIG. 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 FIG. 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 FIG. 2A. These masses may now be of a size that they can produced by directly moulding the mass elements into the bladder wall 11, particularly by providing localised regions of increased bladder wall thickness.
[0074] FIGS. 3B and 3C shows an enlarged region B of FIG. 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 have a 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.
[0075] 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. FIG. 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 FIG. 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.
[0076] FIGS. 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 FIG. 2A.
[0077] 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. FIGS. 6A to 6E illustrate an embodiment that addresses these issues, while also removing the requirement in the context of the FIG. 2 arrangement to attach the masses inside the bladder during assembly of the bladder.
[0078] In the embodiment of FIGS. 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 FIG. 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.
[0079] In the case of the strip shown in FIG. 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. FIG. 6C shows an alternative form of strip 13. In the embodiment illustrated by FIG. 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. This arrangement is more clearly shown in FIG. 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.
[0080] FIG. 6D shows an alternative arrangement in which the same strip from FIG. 6D 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.
[0081] 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. FIG. 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.
[0082] While the embodiments of FIGS. 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 FIG. 2, two other examples for distributing the balancing mass are shown in FIGS. 7A to 8B. Each of these shows balancing mass elements distributed with respect to three balancing points as shown in FIG. 2A, but the same balancing mass elements could also be arranged with respect to four or more balancing points, as shown in FIG. 2C.
[0083] FIGS. 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 FIG. 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 FIG. 2C.
[0084] FIGS. 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 FIGS. 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 FIG. 2A, although a circular region could alternatively be provided for each of the four balancing points of FIG. 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 increased thickness, to minimise the effect these elements have on the inflation of the bladder.
[0085] 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.
[0086] FIG. 9 shows a ball 1 with a bladder 10 having bladder wall 11 and valve 4, as described above with respect to FIG. 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 FIG. 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 FIG. 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.
[0087] According to this positioning of the electronic devices 2a, 2b, there are two options for balancing the mass of the electronic devices.
[0088] 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 FIG. 2, a patch centred on each balancing point, as described with reference to FIG. 7, or a region of integrally formed balancing masses centred on each balancing point, as described with reference to FIG. 8.
[0089] 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 devices 2a, 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 FIG. 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 FIGS. 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 FIG. 2C.
[0090] Finally, FIG. 11 shows a ball 1 with a bladder 10 having bladder wall 11 and valve 4, as described above with respect to FIG. 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 FIG. 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 FIG. 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. FIG. 12 illustrates this.
[0091] In FIG. 12, the first electronic device 2 of the ball of FIG. 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 opposite the 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 FIG. 3A. Additionally, the second electronic device 2 defines a third point 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.
[0092] FIG. 13 illustrates another balancing arrangement that is a variant of the arrangement of FIGS. 11 and 12. In FIG. 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.
[0093] 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 FIG. 3A. In particular, the regular tetrahedron 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.
[0094] 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.
[0095] FIG. 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 thirds of 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.
[0096] While the embodiments of FIGS. 12 to 14 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 FIG. 6A. Alternatively, fewer more massive balancing mass elements could be used, in the case of FIGS. 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.
[0097] Finally, FIGS. 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 FIG. 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 112 is 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.
[0098] 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 FIG. 2A, or could be arranged along tracks along the ellipse analogous to FIG. 3A, 4, 5A, or 6. They could also be distributed around the three balancing points analogously to FIG. 7A or 8A.
[0099] FIG. 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 FIG. 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 FIG. 2C, this reduces the required mass of each balancing mass element while still attaining satisfactory balancing of the electronic device 101.
[0100] The invention may also be understood with reference to the following numbered clauses:
[0101] 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.
[0102] Clause 2. An inflatable ball according to clause 1, 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 two balancing points equally spaced around the second point, preferably at least three balancing points equally spaced around the second point.
[0103] Clause 3. An inflatable ball according to clause 1 or clause 2, 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, 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.
[0104] Clause 4. An inflatable ball according to any of the preceding clauses, comprising 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.
[0105] Clause 5. An inflatable ball according to any of the preceding clauses, wherein the one or more balancing mass elements comprises 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.
[0106] Clause 6. An inflatable ball according to clause 5, wherein the first point lies perpendicular to the plane of the circle or the ellipse from the centre of the circle or the ellipse.
[0107] Clause 7. An inflatable ball according to clause 5, 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.
[0108] Clause 8. An inflatable ball according to any of the preceding clauses, wherein the one or more balancing mass elements comprises one or more continuous strips or patches, preferably adhesive strips or patches, attached on or over the bladder wall.
[0109] Clause 9. An 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.
[0110] Clause 10. An inflatable ball according to clause 9, comprising a plurality of balancing mass elements formed integrally with the bladder wall by increased wall-thickness portions of the bladder wall.
[0111] Clause 11. An inflatable ball according to clause 10, 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.
[0112] Clause 12. An inflatable ball according to clause 11, 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.
[0113] Clause 13. An inflatable ball according to any of clauses 10 to 12, wherein each increased wall-thickness portion of the bladder wall is surrounded by a portion not having the increased wall thickness.
[0114] Clause 14. An inflatable ball according to any of clauses 10 to 13, 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.
[0115] Clause 15. An inflatable ball according to any of clauses 10 to 14, 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.
[0116] Clause 16. An 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.
[0117] Clause 17. An inflatable ball according to any of the preceding clauses, wherein the at least one device is a first device or first set of devices, and further comprising 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.
[0118] Clause 18. An inflatable ball according to any of the preceding clauses, wherein 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 force transducer and a location tracking device, such as an ultra-wideband transmitter and/or receiver.
[0119] Clause 19. An inflatable ball according to any of the preceding clauses, wherein the bladder further comprises a valve for inflating the inflatable interior of the ball, wherein the valve is not one the devices balanced by the distributed balancing mass.
[0120] Clause 20. An inflatable ball according to any of the preceding clauses, wherein the bladder defines a substantially spherical inflatable interior of the ball.
[0121] Clause 21. An 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.
[0122] Clause 22. 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.
[0123] Clause 23. A method according to clause 22, wherein 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.
[0124] Clause 24. A method according to clause 22 or clause 23, 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.
[0125] Clause 25. A method according to clause 24, 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.
[0126] Clause 26. A method according to any of clauses 22 to 25, adapted to manufacture an inflatable ball according to any of clauses 1 to 21.
