WO2015198028A1

WO2015198028A1 - Wheel apparatus

Info

Publication number: WO2015198028A1
Application number: PCT/GB2015/051817
Authority: WO
Inventors: Ian Henderson
Original assignee: Henderson Marine Services Limited
Priority date: 2014-06-23
Filing date: 2015-06-23
Publication date: 2015-12-30
Also published as: GB201411154D0; GB2527520A

Abstract

A wheel apparatus comprising a spherical wheel, wherein the spherical wheel is rotatably supported by a support member, and wherein the support member includes at least one spherical wheel contact member, the at least one spherical wheel contact member being moveable between a first position in which the at least one spherical wheel contact member is in contact with the spherical wheel, and a second position in which the at least one spherical wheel contact member is out of contact with the spherical wheel.

Description

Wheel apparatus

The present invention relates to a wheel apparatus, particularly, but not exclusively, to a wheel apparatus for a vehicle and a vehicle incorporating the wheel apparatus.

Known wheel apparatuses operate to provide support to objects, such as vehicles, or parts thereof. Known wheel apparatuses, such as castor wheels, are capable of orientating in different directions. This allows the object attached to the castor wheel to be moved in various directions.

While such known wheel apparatuses are capable of providing rotational support to objects, such as vehicles, their operation is otherwise limited. The present inventor has appreciated the shortcomings in these known wheel apparatuses.

According to a first aspect of the present invention there is provided a wheel apparatus comprising:

a spherical wheel, wherein the spherical wheel is rotatably supported by a support member, and wherein the support member includes at least one spherical wheel contact member, the at least one spherical wheel contact member being moveable between a first position in which the at least one spherical wheel contact member is in contact with the spherical wheel, and a second position in which the at least one spherical wheel contact member is out of contact with the spherical wheel.

The spherical wheel may be rotatably supported by the support member such that it may rotate in any direction. That is, the spherical wheel may be supported by the support member such that it may rotate in any direction relative to the support member.

The support member may be configured such that the spherical wheel is substantially located within the support member.

The support member may be configured such that it substantially encloses the spherical wheel therein. The support member may be configured such that at least a portion of the spherical wheel protrudes therefrom. The spherical wheel may protrude from a lower portion of the support member.

The support member may define a portion of a spherical-shaped spherical wheel contact surface.

The support member may include a bearing assembly, the bearing assembly being configured to rotatably support the spherical wheel. The bearing assembly is fixedly attached to the support member.

The bearing assembly may comprise a plurality of spherical bearings, the spherical bearings being configured to be rotatable relative to the support member. The spherical bearings may be configured to be rotatable in any direction relative to the support member. The spherical bearings are non- directional bearings.

The bearing assembly may be arranged such that the spherical bearings are located around the spherical wheel. The spherical bearings may be equidistantly located around the spherical wheel. In this arrangement the bearing assembly is a ring-shaped member, or toroid, with the spherical bearings being located equidistantly around the bearing assembly.

The bearing assembly may include a first bearing assembly and a second bearing assembly, each bearing assembly including a plurality of spherical bearings. The first and second bearing assemblies may be connected to one another. The spherical bearings being configured to be rotatable relative to the support member. The spherical bearings may be configured to be rotatable in any direction relative to the support member. Each bearing assembly may be arranged such that the spherical bearings are located around the spherical wheel. The spherical bearings may be equidistantly located around the spherical wheel.

The first and second bearing assemblies may be located on either side of a diameter of the spherical wheel.

The bearing assembly may be horizontally arranged. The first and second bearing assemblies may be horizontally arranged. The first bearing assembly may be located above the second bearing assembly.

The bearing assembly may be configured to transfer loads between the spherical wheel and the support member.

The wheel apparatus may include a main housing. The support member may be attached to the main housing. The at least one spherical wheel contact member may be moveably attached to the main housing.

The support member may include one or more attachment portions for attaching the wheel apparatus to an object. The at least one spherical wheel contact member may be translatable between the first position and the second position. The at least one spherical wheel contact member may be rotatable between the first position and the second position. The at least one spherical wheel contact member may be pivotable between the first position and the second position.

The at least one spherical wheel contact member may be biased towards the second position. The at least one spherical wheel contact member may be spring biased towards the second position.

The at least one spherical wheel contact member may be a roller member, the roller member being configured to be rotatable relative to the support member.

The roller member may be housed in a housing of the at least one spherical wheel contact member. The roller member may be resiliently mounted within the housing. The roller member may be sprung within the housing.

The roller member may rotate, or pivot, relative to the housing of the at least one spherical wheel contact member.

The roller member may be configured to be in contact with the spherical wheel in the first position and out of contact with the spherical wheel in the second position. When the roller member is in contact with the spherical wheel, rotation of the spherical wheel causes rotation of the roller member, and vice versa. The roller member may be configured to rotate freely with respect to the support member.

The roller member may be configured such that it does not rotate freely with respect to the support member. In this arrangement the roller member may be braked, such that it does not rotate freely with respect to the support member. The at least one spherical wheel contact member may include a roller member braking device. The roller member braking device being configured to inhibit rotation of the roller member.

The roller member may rotate about an axis. The axis of rotation of the roller member may be fixed relative to the support member. The axis of rotation of the roller member may be arranged to lie in a horizontal plane. This may be termed the horizontal axis.

The axis of rotation of the roller member may be adjustable relative to the support member. In this arrangement the axis of rotation of the roller member remains lying on a horizontal plane, but may rotate thereabout. The roller member may be adjustable about a vertical axis relative to the support member.

The roller member may be a cylindrical member.

The roller member may be an ellipsoidal member. The roller member may be a truncated ellipsoidal member. The roller member may be truncated at both ends of the member.

The at least one spherical wheel contact member may include at least one brake pad. The at least one brake pad being configured to be moveable with the at least one spherical wheel contact member between the first and second positions.

The at least one brake pad may be arranged either side of the at least one spherical wheel contact member.

The at least one brake pad may be arranged either side of the roller member. The at least one spherical wheel contact member and the brake pad may be arranged together such that the at least one spherical wheel contact member contacts the spherical wheel before the brake pad as the at least one spherical wheel contact member is moved towards the first position. In this arrangement the at least one spherical wheel contact member is set lower than the brake pad relative to the support member. In this

arrangement, as the at least one spherical wheel contact member is moved towards the spherical wheel, the at least one spherical wheel contact member comes into contact with the spherical wheel before the brake pad. Further movement of the at least one spherical wheel contact member towards the spherical wheel causes the brake pad to come into contact with the spherical wheel.

The roller member and the brake pad may be arranged together such that the roller member contacts the spherical wheel before the brake pad as the roller member is moved towards the first position. In this arrangement the roller member is set lower than the brake pad relative to the support member. In this arrangement, as the roller member is moved towards the spherical wheel, the roller member comes into contact with the spherical wheel before the brake pad. Further movement of the roller member towards the spherical wheel causes the brake pad to come into contact with the spherical wheel.

The spherical wheel may be at least partially resilient. The outer surface of the spherical wheel may be resilient. The spherical wheel may be covered with a resilient material.

The spherical wheel may made from steel, aluminium, rubber, man-made plastic or composite material. The spherical wheel may be wholly or partially inflatable.

The outer surface of the spherical wheel may be made from prepared steel, aluminium, rubber, man-made plastic or composite material. The outer surface of the spherical wheel may be wholly or partially inflatable.

The spherical wheel may have a textured surface. The spherical wheel may have an irregular, or uneven, surface. The spherical wheel may have a tread pattern thereon. The support member may include two or more spherical wheel contact members. The support member may include a plurality of spherical wheel contact members.

The spherical wheel contact members may be translatable between the first position and the second position. The spherical wheel contact members may be rotatable between the first position and the second position. The spherical wheel contact members may be pivotable between the first position and the second position. The spherical wheel contact members may be biased towards the second position. The spherical wheel contact members may be spring biased towards the second position. The spherical wheel contact members may be roller members, the roller members being configured to be rotatable relative to the support member.

The roller members may be housed in a housing of the spherical wheel contact members. The roller members may be housed in one housing. In this arrangement the support member may include one housing that includes all of the roller members therein. The roller members may be resiliently mounted within the housing. The roller members may be sprung within the housing. The roller members may rotate relative to the housing.

The roller members may be configured to be in contact with the spherical wheel in the first position and out of contact with the spherical wheel in the second position. When the roller members are in contact with the spherical wheel, rotation of the spherical wheel causes rotation of the roller members, and vice versa.

The roller members may be configured to rotate freely with respect to the support member.

The roller members may be configured such that they do not rotate freely with respect to the support member. In this arrangement the roller members may be braked, such that they do not rotate freely with respect to the support member. The spherical wheel contact member may include a roller member braking device. The roller member braking device being configured to inhibit rotation of the roller members.

The roller members may rotate about an axis. The axis of rotation of the roller members may be fixed relative to the support member. The axis of rotation of each roller member may be arranged to lie in a horizontal plane. This may be termed the horizontal axis.

The axis of rotation of the roller members may be adjustable relative to the support member. In this arrangement the axis of rotation of each roller member remains lying on a horizontal plane, but may rotate thereabout. The axes of rotation of the roller members may be parallel. The roller members may be adjustable about a vertical axis relative to the support member.

The roller members may be cylindrical members.

The roller members may be ellipsoidal members. The roller members may be truncated ellipsoidal members. The roller members may be truncated at both ends of the member.

The spherical wheel contact members may include at least one brake pad. The at least one brake pad being configured to be moveable with the spherical wheel contact members between the first and second positions.

The at least one brake pad may be arranged either side of the spherical wheel contact members, or between adjacent spherical wheel contact members. The at least one brake pad may be arranged either side of the roller members, or between adjacent roller members.

The spherical wheel contact members may include two or more brake pads. The spherical wheel contact members may include a plurality of brake pads. Each brake pad being configured to be moveable with the spherical wheel contact members between the first and second positions.

The brake pads may be arranged either side of the spherical wheel contact members, or between adjacent spherical wheel contact members.

The brake pads may be arranged either side of the roller members, or between adjacent roller members. The spherical wheel contact members and the brake pads may be arranged together such that the spherical wheel contact members contact the spherical wheel before the brake pads as the spherical wheel contact members are moved towards the first position. In this arrangement the spherical wheel contact members are set lower than the brake pads relative to the support member. In this arrangement, as the spherical wheel contact members are moved towards the spherical wheel, the spherical wheel contact members come into contact with the spherical wheel before the brake pads. Further movement of the spherical wheel contact members towards the spherical wheel causes the brake pads to come into contact with the spherical wheel. Each spherical wheel contact member comes into contact with the spherical wheel at the same time. That is, each spherical wheel contact member is positioned along an arc of a circle. The arc of the circle is configured to be complementary to the outer surface of the spherical wheel. The roller members and the brake pads may be arranged together such that the roller members contact the spherical wheel before the brake pads as the roller members are moved towards the first position. In this arrangement the roller members are set lower than the brake pads relative to the support member. In this arrangement, as the roller members are moved towards the spherical wheel, the roller members come into contact with the spherical wheel before the brake pads. Further movement of the roller members towards the spherical wheel causes the brake pads to come into contact with the spherical wheel. Each roller member comes into contact with the spherical wheel at the same time. That is, each roller member is positioned along an arc of a circle. The arc of the circle is configured to be complementary to the outer surface of the spherical wheel. The housing of the spherical wheel contact members may be arranged such that the contact members are arranged along an arc of a circle. The arc of the circle being complementary to the outer surface of the spherical wheel, such that each spherical wheel contact member comes into contact with the spherical wheel at the same time as the support member is moved towards the first position.

The housing of the spherical wheel contact members may be arranged such that the roller members are arranged along an arc of a circle. The arc of the circle being complementary to the outer surface of the spherical wheel, such that each roller member comes into contact with the spherical wheel at the same time as the support member is moved towards the first position.

The at least one brake pad may be housed in the housing of the spherical wheel contact member. The brake pads may be housed in the housing of the spherical wheel contact members. The spherical wheel and the spherical wheel contact members may be arranged such that, when the spherical wheel contact members are in the first position, the contact between the spherical wheel contact members and the spherical wheel causes at least a portion of the outer surface of the spherical wheel to undulate. The undulation of the at least a portion of the outer surface may be particularly effective between adjacent spherical wheel contact members. The amount of undulation of the at least a portion of the outer surface of the wheel may be proportional to the amount of force that is applied to spherical wheel contact member as it contacts the spherical wheel.

The spherical wheel and the roller members may be arranged such that, when the roller members are in the first position, the contact between the roller members and the spherical wheel causes at least a portion of the outer surface of the spherical wheel to undulate. The undulation of the at least a portion of the outer surface may be particularly effective between adjacent roller members. The amount of undulation of the at least a portion of the outer surface of the wheel may be proportional to the amount of force that is applied to roller member as it contacts the spherical wheel.

Where a brake pad is located between adjacent spherical wheel contact members, or roller members, undulation of the portion of the outer surface of the spherical wheel between the adjacent spherical wheel contact members, or roller members, causes the outer surface of the spherical wheel to come into contact with the brake pad. The support member may include one or more additional spherical wheel contact members. The support member may include two or more additional spherical wheel contact members.

Each additional spherical wheel contact member may be configured to be moveable between a first position in which the additional spherical wheel contact member is in contact with the spherical wheel, and a second position in which the additional spherical wheel contact member is out of contact with the spherical wheel.

Each additional spherical wheel contact member may be configured to operate independently from the at least one spherical wheel contact member and any other additional spherical wheel contact members.

The additional spherical wheel contact members may be translatable between the first position and the second position. The additional spherical wheel contact members may be rotatable between the first position and the second position. The additional spherical wheel contact members may be pivotable between the first position and the second position.

The additional spherical wheel contact members may be biased towards the second position. The additional spherical wheel contact members may be spring biased towards the second position.

The additional spherical wheel contact members may be roller members, the roller members being configured to be rotatable relative to the support member. The roller members may be housed in a housing of the additional spherical wheel contact members. The roller members may be resiliently mounted within the housing. The roller members may be sprung within the housing.

The roller members may rotate relative to the housing of the additional spherical wheel contact members.

The roller members may be configured to be in contact with the spherical wheel in the first position and out of contact with the spherical wheel in the second position. When the roller members are in contact with the spherical wheel, rotation of the spherical wheel causes rotation of the roller members, and vice versa. The roller members may be configured to rotate freely with respect to the support member.

The roller members may be configured such that they do not rotate freely with respect to the support member. In this arrangement the roller members may be braked, such that they do not rotate freely with respect to the support member. The additional spherical wheel contact members may include a roller member braking device. The roller member braking device being configured to inhibit rotation of the roller members. The roller members may rotate about an axis. The axes of rotation of the roller members may be fixed relative to the support member. The axes of rotation of the roller members may be arranged to lie in a horizontal plane. This may be termed the horizontal axis. The axes of rotation of the roller members may be adjustable relative to the support member. In this arrangement the axes of rotation of the roller members remain lying on a horizontal plane, but may rotate thereabout. The roller members may be adjustable about a vertical axis relative to the support member.

The roller members may be cylindrical members.

The additional spherical wheel contact members may include at least one brake pad. The at least one brake pad being configured to be moveable with the additional spherical wheel contact members between the first and second positions.

The at least one brake pad may be arranged either side of the additional spherical wheel contact members.

The at least one brake pad may be arranged either side of the roller members.

The additional spherical wheel contact members and the brake pad may be arranged together such that the additional spherical wheel contact members contacts the spherical wheel before the brake pad as the additional spherical wheel contact members are moved towards the first position. In this arrangement the additional spherical wheel contact members are set lower than the brake pad relative to the support member. In this arrangement, as additional spherical wheel contact members are moved towards the spherical wheel, the additional spherical wheel contact members come into contact with the spherical wheel before the brake pad. Further movement of the additional spherical wheel contact members towards the spherical wheel causes the brake pad to come into contact with the spherical wheel.

The roller members and the brake pad may be arranged together such that the roller members contact the spherical wheel before the brake pad as the roller members are moved towards the first position. In this arrangement the roller members are set lower than the brake pad relative to the support member. In this arrangement, as the roller members are moved towards the spherical wheel, the roller members come into contact with the spherical wheel before the brake pad. Further movement of the roller members towards the spherical wheel causes the brake pad to come into contact with the spherical wheel.

Each additional spherical wheel contact member may include a plurality of roller members and a plurality of brake pads. The construction of each additional spherical wheel contact member may be identical to the at least one spherical wheel contact member described above.

According to a second aspect of the invention there is provided a wheel system comprising two or more wheel apparatus according to the first aspect of the invention.

The wheel system may include a plurality of wheel apparatuses according to the first aspect of the invention.

Embodiments of the second aspect of the invention may include one or more features of the first aspect of the invention or its embodiments. Similarly, embodiments of the first aspect of the invention may include one or more features of the second aspect of the invention or its embodiments.

According to a third aspect of the invention there is provided a keel for a watercraft comprising a wheel apparatus according to the first aspect of the invention.

The keel may include two or more wheel apparatuses. The wheel apparatus may be configured to provide support to the keel if the keel is moving over land.

Embodiments of the third aspect of the invention may include one or more features of the first aspect of the invention or its embodiments. Similarly, embodiments of the first aspect of the invention may include one or more features of the third aspect of the invention or its embodiments.

According to a fourth aspect of the present invention there is provided a landing gear for a vehicle comprising a wheel apparatus according to the first aspect of the invention.

The landing gear may include two or more wheel apparatuses.

The vehicle may be an aircraft. The vehicle may be a watercraft.

Embodiments of the fourth aspect of the invention may include one or more features of the first aspect of the invention or its embodiments.

Similarly, embodiments of the first aspect of the invention may include one or more features of the fourth aspect of the invention or its embodiments. According to a fifth aspect of the present invention there is a provided a vehicle comprising a wheel apparatus according to the first aspect of the invention. The vehicle may include two or more wheel apparatuses.

The vehicle may be a watercraft. The vehicle may be an aircraft. The watercraft may be a non-displacement craft. The watercraft may be a hovercraft, including hovercraft or air cushion vehicle mainly or solely operated on land, naviplane, shallow draught watercraft such as paddle driven vessels, airboats or fan boats, jon boats, air thrust boats or air propeller powered boats.

The wheel apparatus may be provided on a keel of the vehicle.

Embodiments of the fifth aspect of the invention may include one or more features of the first aspect of the invention or its embodiments. Similarly, embodiments of the first aspect of the invention may include one or more features of the fifth aspect of the invention or its embodiments.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompany drawings, in which:-

Figure 1 is a side view of a wheel apparatus according to the present invention;

Figure 2 is a top view of the wheel apparatus of figure 1 ;

Figure 3 is a partial cross-sectional side view of a spherical wheel contact member contacting the spherical wheel of the wheel apparatus; Figure 4 is a partial cross-sectional end view of the spherical wheel contact members in contact with and out of contact with the spherical wheel of the wheel apparatus; and

Figure 5 is a detailed partial cross-sectional end view of the spherical wheel contact members contacting the spherical wheel of the wheel apparatus. Figures 1 and 2 illustrate a wheel apparatus 10. The wheel apparatus 10 includes a spherical wheel 12, a support member 14 and a spherical wheel contact member 16. The wheel apparatus 10 may include a main housing 1 1 , partially illustrated in figure 1 . The support member 14 may be attached to the main housing 1 1 . The at least one spherical wheel contact member 16 may be moveably attached to the main housing 1 1. The main housing may be any suitable structure, such as a framework, or the like, that is capable of housing and supporting the support member 14, the spherical wheel contact member 16 and the spherical wheel. The support member 14 is configured to rotatably support the spherical wheel 12. That is, the support member 14 is configured to allow the spherical wheel 12 to rotate in any direction within the wheel apparatus 10.

In the embodiment illustrated and described here the support member 14 includes a bearing assembly 18 that includes a plurality of spherical bearings 20. The bearing assembly 18 is in the form of a cage, or frame, which allows the bearings 20 to rotate therein. The bearings 20 are configured to be rotatable in any direction. That is, the bearings 20 are non-directional bearings. The bearing assembly 18 is attached to the support member 14. As illustrated in figure 1 , the bearing assembly 18 includes a first bearing assembly 18a and a second bearing assembly 18b. The first bearing assembly 18a is located above a horizontal diameter 12a of the spherical wheel 12 and the second bearing assembly 18b is located below the horizontal diameter 12a of the spherical wheel 12. The first and second bearing assemblies 18a, 18b are ring-shaped members that surround the spherical wheel 12. This arrangement confines the spherical wheel 12 within the support member 14 and allows loads to be transferred from the spherical wheel 12 through the support member 14 to the main housing 1 1.

The bearing assembly 18 may be configured to be sprung within the main housing 1 1 . That is, the first and second bearing assemblies 18a, 18b may be configured to be resiliently attached, or mounted to, the main housing 1 1 .

The spherical wheel 12 is arranged such that it protrudes from the lower portion of the main housing 1 1 to contact the ground 21 , as illustrated in figure 1 . As best illustrated in figure 2, the bearing assembly 18 is arranged such that the bearings 20 are located equidistantly around the bearing assembly 18.

The spherical wheel 12 may be made from steel, aluminium, rubber, man- made plastic or composite material. The spherical wheel 12 may be wholly or partially inflatable. The spherical wheel 12 may be at least partially resilient, or the outer surface 12b of the spherical wheel may be resilient. As illustrated in figures 3 and 5, the outer surface 12b of the spherical wheel 12 has a tread pattern thereon. This enhances the frictional contact between the spherical wheel 12 and the roller members 16a, as describe below.

The spherical wheel contact member 16 is moveable between a first position in which the spherical wheel contact member 16 is in contact with the spherical wheel 12, and a second position in which the spherical wheel contact member 16 is out of contact with the spherical wheel 12, as best illustrated in figure 4. In the embodiment illustrated and described here the spherical wheel contact member 16 is vertically moveable between the first and second position. However, it should be appreciated that other movements of the spherical wheel contact member 16 are possible. The spherical wheel contact member 16 is spring biased towards the second position. In the embodiment illustrated and described here the spherical wheel contact member 16 comprises a plurality of roller members 16a, as illustrated in figures 3 and 4. The roller members 16a are configured to rotate relative to the support member 14 and the spherical wheel 12. The roller members 16a are rotatably mounted to a housing 22. As described further below, the roller members 16a may be configured to rotate freely with respect to the housing 22. Alternatively, or additionally, the roller members 16a may include a braking device (not illustrated) to inhibit rotation of the roller member 16a. The housing 22 may be moveable between the first position and the second position. The roller members 16a are also resiliently mounted within the housing 22. That is, the roller members 16a are sprung within the housing 22, such that they may move relative to the housing 22 when subjected to a load, as described further below. As best illustrated in figure 3, the roller members 16a are ellipsoidal- shaped members with truncated end portions. The roller members 16a rotate about a horizontal axis 17. As described further below, the roller members 16a may also rotate relative to the support member 14. That is, the roller members 16a may be rotatable, or pivotable, about a vertical axis 19. In this arrangement the roller members 16a may pivot or rotate relative to the housing 22. As illustrated best in figures 4 and 5, the spherical wheel contact member 16 may include a plurality of brake pads 24 located between the roller members 16a. The brake pads 24 are located within the housing 22. The brake pads 24 are substantially rectangular members and are made from rubber, metal, ceramic, man-made plastic or composite material.

As best illustrated in figure 4, the roller members 16a are arranged such that they protrude from the lower portion of the housing 22a. As described above, the roller members 16a are spring biased within the housing 22. The roller members 16a are spring biased towards the spherical wheel 12, i.e. biased out of the housing 22. When the roller members 16a are out of contact with the spherical wheel 12 they protrude a maximum extent out of the lower portion 22a the housing 22. When the roller members 16a are in contact with the spherical wheel, i.e. loaded, they are pushed back into the housing 22 by an amount that is dependent upon the load and the spring constant of the spring. The solid lines of figure 4 illustrate the situation where the rollers 16a are out of contact with the spherical wheel 12. The dashed lines of figure 4 illustrate the situation where the rollers 16a are in contact with the spherical wheel 12. Here the roller members 16a are pushed into the housing 22. The brake pads 24 also protrude from the lower portion of the housing 22a. However, the brake pads 24 are not sprung with the housing 22.

As described further below, the roller members 16a and the brake pads 24 are arranged together such that the roller members 16a contact the spherical wheel 12 before the brake pads 24 as the roller members 16a are moved towards the first position. In this arrangement the roller members 16a are positioned lower than the brake pads 24 relative to the support member 14. In this arrangement, as the roller members 16a are moved towards the spherical wheel 12, the roller members 16a come into contact with the spherical wheel 12 before the brake pads 24. Further movement of the roller members 16a towards the spherical wheel 12 causes the brake pads 24 to come into contact with the spherical wheel 12.

As illustrated best in figures 1 and 4, the housing 22 is in the shape of an arc of a circle. Each roller member 16a therefore comes into contact with the spherical wheel 12 at the same time. That is, each roller member 16a is positioned along an arc of a circle. The arc of the circle is configured to be complementary to the outer surface of the spherical wheel 12.

As illustrated in figure 5, the spherical wheel 12 and the roller members 16a are arranged such that, when the roller members 16a are in the first position, the contact between the roller members 16a and the spherical wheel 12 causes the outer surface 12b of the spherical wheel 12 to undulate. The undulation of the outer surface 12b may be particularly effective between adjacent roller members 16a. The amount of undulation of the outer surface 12b of the wheel 12 may be proportional to the amount of force that is applied to roller member 16a as it contacts the spherical wheel 12. Undulation of the outer surface 12b of the spherical wheel 12 between the adjacent roller members 16a causes the outer surface 12b of the spherical wheel 12 to come into contact with the brake pad 24. As illustrated in figure 2, the wheel apparatus 10 may also include one or more additional spherical wheel contact members 26. In the embodiment illustrated and described here the additional spherical wheel contact members 26 are smaller, or shorter, than the spherical wheel contact member 16. However, it should be appreciated that the additional spherical wheel contact members 26 could be any suitable size or length.

The construction and operation of the additional spherical wheel contact members 26 is generally identical to the construction and operation of the spherical wheel contact member 16 described above.

As described further below, the additional spherical wheel contact members 26 may be operable separately from each other and the spherical wheel contact member 16. The operation of the wheel apparatus 10 will now be described. The wheel apparatus 10 is configured such that the spherical wheel 12 may move in any direction, but can be gradually biased in a particular direction of rotation under control. This is effected by the spherical wheel contact member 16. A braking effect may also be applied to the spherical wheel 12 in this direction or in the direction of motion.

As described above, the wheel apparatus 10 consists of an un-driven spherical wheel 12 within a bearing cage (an example of a support member 14. The spherical wheel 12 is not restricted in rotation in the vertical, longitudinal or horizontal axes. When the wheel apparatus 10 is used on a vehicle, such as a watercraft, or a part thereof, such as the keel of a watercraft, the weight to be supported is taken by the bearing cage 14 and transferred to the spherical wheel 12 via the spherical bearings 20 which have no direction bias.

When a direction of bias is required to be applied to the spherical wheel 12, the spherical wheel contact member 16 is moved towards the spherical wheel 12, and the roller members 16a are brought to bear on the outer surface 12b of the spherical wheel 12, as best illustrated in figure 3. The roller members 16a have a convex cross section so initially only a little surface contact is made between the roller members 16a and the outer surface 12b of the spherical wheel 12. If the spherical wheel 12 is not rotating in line with the rollers members 16a, i.e. the axis of rotation of the spherical wheel 12 is not parallel to the axes of rotation 16b of the roller members 16a, the friction created therebetween will cause a biasing force that acts to try and align the axis of rotation of the spherical wheel 12 with the axes of rotation 16b of the roller members 16a. This causes the spherical wheel 12 to change direction with respect to the ground 21 . This frictional force created is a result of the scrubbing between the roller members 16a and the spherical wheel 12. Increased downward force by the roller members 16a will increase the surface area in contact with the outer surface 12b of the spherical wheel 12, which increases the biasing force exerted to align the axis of rotation of the spherical wheel 12 with the axes of rotation 16b of the roller members 16a. This will also cause a modest braking effect due to the rolling resistance and surface areas in contact with one another. If the spherical wheel 12, or the outer surface 12b thereof, is made from a resilient, or compressible, material the biasing and braking effect may be increased, as the contact surface areas are increased. The direction of bias may be varied by rotating the spherical wheel contact member 16, or roller members 16a, or by fitting additional spherical wheel contact members 26, as described above, at 90° to the spherical wheel contact member 16, as illustrated in figure 2. By applying and releasing downward force to the assemblies positioned at right angles to each other, the spherical wheel 12 can be steered. When the wheel apparatus 10 is fitted to a vehicle, the vehicle may therefore also be steered.

In addition to the braking action described above, additional braking of the spherical wheel 12 may be obtained from the brake pads 24. As described above and illustrated in figure 5, if the roller members 16a are sprung within the housing 22, the brake pads 24 will make contact with the outer surface 12b of the spherical wheel 12 when a downward force of the spherical wheel contact member 16 is applied, as the roller members 16a will move upwards inside the housing 22 and the brake pads 24 will come into contact with the outer surface 12b of the spherical wheel 12.

Additionally, or alternatively, if the roller members 16a are not sprung, the braking force may be augmented by the spherical wheel 12, or outer surface 12b thereof, being allowed to compress. The downward force of the roller members 16a causes local undulations on the outer surface 12b which pushes the outer surface 12b towards the brake pads 24, which further increase rolling resistance, as illustrated in figure 5.

One use of the wheel apparatus 10 may be in landing gear for vehicles, such as aircraft or watercraft. The wheel apparatus 10 may be useful if the surface medium changes when direction cannot be predicted, such as a form of landing gear. If a standard swivel caster is off the ground, it may become orientated in such a way that a there is a substantial difference between the angle of the caster and the direction of motion. This differential can be as much as 180° from the direction of motion. If so, a violent change of direction initially occurs when contact is made, which may cause instability, especially at high speeds. If the wheel apparatus 10 is used in such conditions the spherical wheel 12 does not cause a change in direction of a craft if utilised as a form of landing gear. This is useful if the initial direction of motion is to be maintained and then corrected in a controlled manner. A simple example would be an aircraft landing in strong cross winds such that the heading is substantially different to the direction of motion. Aircraft in this situation have to make a last minute correction to align the heading with the runway due to fixed direction wheels. This makes the aircraft liable to overturning forces caused by the cross-wind in addition to the sudden action of a change in direction. If the aircraft could land with the heading required in order to maintain the course over the ground, that is the line of the runway, this would dispense with the need for a sudden course change at one of the most dangerous times. Braking would be required in the direction of motion and subsequently the direction bias would be later required to align the aircraft with the runway. Similarly, this could be used, in theory for take-off. Unlike a swivel caster wheel, the weight of the craft is supported directly above the wheel apparatus 10, as described above.

Modifications and improvements may be made to the above without departing from the scope of the present invention. For example, although only one wheel apparatus 10 has been illustrated and described above, it should be appreciated that there could be provided a wheel system, where the wheel system includes two or more wheel apparatus 10. The wheel apparatus 10, or wheel system incorporating two or more wheel apparatus 10, may be used with a vehicle, such as an aircraft or watercraft, to assist manoeuvring, steering and braking.

Claims

1 . A wheel apparatus comprising:

2. The wheel apparatus of claim 1 , wherein the support member is configured such that the spherical wheel is substantially located within the support member.

3. The wheel apparatus of claim 1 or claim 2, wherein the spherical wheel protrudes from a lower portion of the support member.

4. The wheel apparatus of any preceding claim, wherein the support member includes a bearing assembly, the bearing assembly being attached to the support member and configured to rotatably support the spherical wheel.

5. The wheel apparatus of claim 4, wherein the bearing assembly comprises a plurality of spherical bearings, the spherical bearings being configured to be rotatable relative to the support member.

6. The wheel apparatus of claim 4 or claim 5, wherein the bearing assembly are arranged such that the spherical bearings are located around the spherical wheel.

7. The wheel apparatus of claim 6, wherein the spherical bearings may be equidistantly located around the spherical wheel.

8. The wheel apparatus of any of claims 4 to 7, wherein the bearing assembly includes a first bearing assembly and a second bearing assembly, each bearing assembly including a plurality of spherical bearings located around the spherical wheel.

9. The wheel apparatus of claim 7, wherein the first and second bearing assemblies are located on either side of a diameter of the spherical wheel.

10. The wheel apparatus of any preceding claim, wherein the at least one spherical wheel contact member is translatable, pivotable or rotatable between the first position and the second position.

1 1 . The wheel apparatus of any preceding claim, wherein the at least one spherical wheel contact member is biased towards the second position.

12. The wheel apparatus of any preceding claim, wherein the at least one spherical wheel contact member is a roller member, the roller member being configured to be rotatable relative to the support member.

13. The wheel apparatus of claim 12, wherein the roller member is housed in a housing of the at least one spherical wheel contact member.

14. The wheel apparatus of claim 13, wherein the roller member is resiliently mounted, or sprung, within the housing.

15. The wheel apparatus of any preceding claim, wherein the at least one spherical wheel contact member rotates or pivots relative to the support member.

16. The wheel apparatus of any of claims 12 to 15, wherein the roller member is configured to be in contact with the spherical wheel in the first position and out of contact with the spherical wheel in the second position.

17. The wheel apparatus of any of claims 12 to 16, wherein the roller member includes a braking device to inhibit the rotation of the roller member.

18. The wheel apparatus of any of claims 12 to 17, wherein the roller member rotates about an axis, the axis being arranged to lie in a horizontal plane.

19. The wheel apparatus of claim 18, wherein the roller member is adjustable such that its axis of rotation is adjustable on the horizontal plane.

20. The wheel apparatus of any of claims 12 to 18, wherein the roller member is an ellipsoidal member.

21 . The wheel apparatus of any preceding claim, wherein the at least one spherical wheel contact member includes at least one brake pad, the at least one brake pad being configured to be moveable with the at least one spherical wheel contact member between the first and second positions.

22. The wheel apparatus of claim 21 , wherein the at least one brake pad is arranged either side of the roller member.

23. The wheel apparatus of claim 21 or claim 22, wherein the roller member and the brake pad are arranged together such that the roller member contacts the spherical wheel before the brake pad as the roller member is moved towards the first position.

24. The wheel apparatus of any preceding claim, wherein the outer surface of the spherical wheel is resilient.

25. The wheel apparatus of any preceding claim, wherein the spherical wheel has a tread pattern thereon.

26. The wheel apparatus of any preceding claim, wherein the support member includes two or more spherical wheel contact members.

27. The wheel apparatus of claim 26, wherein each spherical wheel contact member is a roller member.

28. The wheel apparatus of claim 27, wherein the roller members are housed in a housing of the spherical wheel contact members.

29. The wheel apparatus of claim 28, wherein the roller members are resiliently mounted, or sprung, within the housing.

30. The wheel apparatus of claim 28 or claim 29, wherein the roller members are rotatable, or pivotable, relative to the housing.

31 . The wheel apparatus of any of claims 27 to 30, wherein the spherical wheel contact members includes at least one brake pad, the at least one brake pad being located between two adjacent roller members.

32. The wheel apparatus of claim 31 , wherein the spherical wheel contact members includes a plurality of brake pads, each brake pad being located between two adjacent roller members.

33. The wheel apparatus of claim 32, wherein the spherical wheel contact members and the brake pads are arranged together such that the spherical wheel contact members contact the spherical wheel before the brake pads as the spherical wheel contact members are moved towards the first position.

34. The wheel apparatus of any of claims 28 to 33, wherein the housing of the spherical wheel contact members is arranged such that the contact members are arranged along an arc of a circle.

35. The wheel apparatus of any of claims 31 to 34, wherein the at least one brake pad is housed in the housing of the spherical wheel contact member.

36. The wheel apparatus of any of claims 32 to 35, wherein the spherical wheel and the spherical wheel contact members are arranged such that, when the spherical wheel contact members are in the first position, the contact between the spherical wheel contact members and the spherical wheel causes at least a portion of the outer surface of the spherical wheel to undulate.

37. The wheel apparatus of any preceding claim, wherein the support member includes one or more additional spherical wheel contact members.

38. The wheel apparatus of claim 37, wherein the support member includes two additional spherical wheel contact members, the additional spherical wheel contact members being located on opposite sides of the at least one spherical wheel contact member.

39. The wheel apparatus of claim 37 or claim 38, wherein each additional spherical wheel contact member is configured to be moveable between a first position in which the additional spherical wheel contact member is in contact with the spherical wheel, and a second position in which the additional spherical wheel contact member is out of contact with the spherical wheel.

40. The wheel apparatus of claim 39, wherein each additional spherical wheel contact member is configured to operate independently from the at least one spherical wheel contact member and any other additional spherical wheel contact members.

41 . A wheel system comprising two or more wheel apparatus according to any of claims 1 to 40.

42. A keel for a watercraft comprising the wheel apparatus of any of claims 1 to 40.

43. The keel of claim 40, wherein the keel includes two or more wheel apparatuses.

44. Landing gear for a vehicle comprising the wheel apparatus of any of claims 1 to 40.

45. The landing gear of claim 44, wherein the vehicle is an aircraft or a watercraft.

46. A vehicle comprising the wheel apparatus of any of claims 1 to 40.

47. The vehicle of claim 46, wherein the vehicle is an aircraft or a watercraft.