The present invention is for a kind of roller skate, where the rotating element is a spherical ball, which gives the skater freedom to move and make movements in any direction.

Roller skates and the like are known in many embodiments, either forming a unit with a shoe or as a separate unit intended to be attached to shoes. Ball roller skates of this kind usually have a front and a rear axle, each carrying one or more wheels. So designed devices are intended to function mainly like ice skates, where skating is done on a steel strip which contacts an ice surface.

For special applications there are various embodiments of the above mentioned basic roller skate design. Roller skates having only one axle are described, e.g. in US patent No. 3 374002, according to which the only axle carries one wheel in a fixed position. According to US patent 3476 399 one axle carries two wheels also in a fixed position. In both of these cases either the heel or the sole of the shoe can be brought in contact with the ground for braking and rest.

There are also special designs to make possible special movements such as pirouettes. US patent 4598 918 describes a device of this kind, where a circular disc is in contact with the ground. The disc can rotate around a vertical axis and has a special design.

There are also known designs of roller skates, where one or more balls make the contact with the ground. One such design is described in US patent No. 3 963 251. Rotation of the skater is then made possible mainly thereby that the device which carries the ball has a bearing comprising a number of

bearing balls which make possible rotation around an essentially vertical axis. This design is intended to be used only on one foot. A roller skate described in US patent No. 4076263 has two balls which funtion as wheels. These balls are on their upper side supported by rolls which are mounted on horizontal axles positioned in right angles against the lengthwise direction of the roller skate. This design means that the balls are free to rotate only around an imagined axis which is parallel with those axles that carry the support rolls.

The present invention is for a kind of roller skates, where the contact with the ground is a spherical ball which is free to rotate in any direction and this kind of roller skate is _. in the following named ball roller skate. The invention is characterized by those characteristics which are mentioned in claim 1. Further embodiments of the invention have those characteristics which are mentioned in the dependent claims.

The invention is below described more in detail by the examples of embodiments which are shown in the enclosed drawings.

Fig. 1 shows a vertical cross section through the centre of the ball which contacts the ground in a preferred embodiment of a ball roller skate according to the invention.

Fig. 2 shows a ball roller skate according to the invention seen from below.

Figs. 3, 4 and 5 show other embodiments of the invention.

The embodiments of Figs. 1 and 2 of a ball roller skate according to the invention comprises a ball 1 intended to contact the ground. This ball is positioned in a cavity 2, the

shape of which closely resembles that of the ball in a fastening device 3. This fastening device is a solid body, the size of which approximately corresponds to the underside of the shoe of the skater. This body can e.g be cast from a metal such as aluminium or some suitable plastic material. The ball 1, which is namned skating ball, is borne by a number of smaller balls 4, 6, 7, 17, 19, which are positioned in therefore arranged cavities in the fastening body 3. These balls 4, 6, 7, 17, 19 function as bearing balls for the skating ball 1 and carries the latter. There are further a number of side balls or braking balls, two of which 5, 15 are shown in Fig. 1. These are separated from the skating ball by a flexible wall material 8, 9. As can be seen in Fig. 2, the ball roller skate in the embodiment of Figs. 1 and 2 has five smaller balls 4, 6, 7, 17, 19 and four braking balls 5, 15, 16, 18.

When skating in a freely chosen direction the skating ball 1 is carried by the supporting balls, where the load is mainly taken by the upper ball 6. The supporting balls are positioned in cavities, where they slip against the walls which have low friction. Depending on the goods of the fastening body 3 it can be required or advantageous to giv.i the cavities for the supporting balls an inner lining of low friction material. When the skater wants to brake or make a turning movement or the like one or both feet are angled so that one or more of the braking balls contact the ground. Those braking balls will then press against the flexible wall material which in turn presses against the skating ball and thereby brakes the movement of the latter. The braking can also be obtained by mounting the balls in the fastening body so that the braking balls influence adjacent supporting balls and through these affect the skating ball. This influence will then mainly depend upon the different rotational speed and direction of

the various balls.

The embodiments of the invention, which are shown in Figs. 3 and 4, are in principle the same when it comes to the skating ball and the support balls but different from the preferred embodiment in that there are no braking balls. The braking can instead be obtained by braking blocks 12, 13, as shown in Fig. 3. In the embodiment shown in Fig. 4 support can be given from the support wheels 10, 11, positioned on the side of the skating ball. It is of course possible to combine these different braking and supporting arrangements in one ball roller skate.

The embodiment of the invention which is shown in Fig. 5 resembles the embodiment of Fig. 4, but instead ^' of two separate supporting wheels there are two pairs of wheels 20 and 21, each having two freely running wheels mounted on an axle. This embodiment may also include braking blocks, as shown in Fig. 3. The braking effect on the skating ball 1 may in these embodiments be obtained thereby that e.g. wheels, wheel mountings or braking blocks have devices to transfer the braking to the skating ball when a wheel or other device contacts the ground. For this purpose some mechanical arrangement is suitable. However, the detailed design of this is outside the scope of the present invention.

The spherical skating ball can be made from various materials depending on the intended use, a ball roller skate according to the invention can be e.g. for general outdoor use on streets and other outdoor ground or for skating on special ground surfaces, indoor or outdoor. The skating ball can be made from steel or plastic and be solid or hollow. The hollow ball can be filled with e.g. a liquid. In this way the properties of the ball roller skate may be adjusted to the

ground surface and to the wishes of the skater.

The fastening body for the ball may also be made in various ways and from various materials, preferably metal or plastic. Also in this case solid or hollow material can be used. Factors influencing the choice of material is among others stiffness, weight and friction properties.

The spherical skating ball is not mainly in contact with the walls of the cavity where it is positioned but is carried by the supporting balls. By braking, however, the flexible wall material between braking ball and skating ball may contact both these balls. The flexible part of the wall can be made from the same material as a fastening body and be a part thereof or be made from a separate material which is then mounted onto the fastening body in a suitable way.