BACKGROUND OF THE INVENTION AND PRIOR ART The present invention refers to a device for transferring a rotary movement from a first axle to a second axle.

There is a plurality of different situations in which there is a need for transferring a rotary movement from a first axle to a second axle. This need is present at, for instance, many types of motor vehicles, such as for instance cars, motor cycles, boats and air crafts, wherein the rotary movement of an output axle from the engine of the motor vehicle is to be transferred to a drive shaft for driving the vehicle at a desired speed in a desired direction. Also in many other types of machines this need of transferring a rotary movement between two axles often is present.

\ When transferring a rotary movement from a first axle to a second axle it is often desirable to be able to vary the transmission ratio between the rotary movements of the axles, for instance in order to obtain different rotary speeds for the second axle at a constant rotary speed of the first axle. To this end, many different kinds of transmission devices have been proposed, such as for instances different kinds of transmission boxes, manual as well as automatic transmission boxes. In known types of transmission boxes, it is usually possible to vary the transmission ratio between the rotary movements of the axles between a determined number of positions, for instance four, five or six. According to a mode of operation according to previously known technique for changing the transmission ratio between the rotary movements of the first axle and the second axle, the change of the transmission ratio is achieved by

bringing gear wheels with various radius connected to the respective axles into engagement with each other. By bringing different gear wheels into engagement with each other, and thereby changing the relation between the radiuses of the gear wheels, which are in engagement with each other, said transmission ratio is changed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a device for transferring a rotary movement between a first axle and a second axle, which provides improved possibilities to vary the transmission ratio between the rotary movements of the axles as required.

This object is achieved according to the invention by a device for device for transferring a rotary movement from a first axle to a second axle, which includes a first transmission element, which is connected to the first axle and arranged to rotate with the first axle, and a second transmission element, which is connected to the second axle and arranged to rotate with the second axle, wherein the first transmission element and the second transmission element have a respective substantially conical peripheral surface, wherein the transmission elements are arranged in such a way that the peripheral surface of the first transmission element and the peripheral surface of the second transmission element abut each other for transferring the rotary movement between the transmission elements, and in which the transmission elements are displaceable in relation to each other, whereby the transmission relation between the rotary movements of the axles is variable.

By means of such a device according to the invention, a continuous variation of the transmission ratio between, the rotary movements of the first and second axles, is enabled.

Consequently, it is possible to vary the transmission ratio in

such a way that it is, at every point of time, adapted to the existing operational conditions. For instance, driving of one of the axles at a constant rotary speed and constant force is possible, wherein the transmission ratio between the axles is varied for being adapted to the counteracting forces of the other axle, wherein the rotary speed of the other axle as a consequence also is varied. By varying the transmission ratio between the rotary movements of the axles, it is also possible to provide a constant rotary speed and a constant force to the axle, to which the rotary movement is transferred, although the rotary speed of the axle, from which the rotary movement is transferred, varies. It is also possible to use the device in such a way that a rotary movement of the first axle is transferred with varying rotary speeds to a rotary movement of the second axle with a varying speed.

According to a preferred embodiment of the invention, the first axle and the second axle are arranged at an angle, preferably a right angle, in relation to each other. Since the device according to the invention according to this embodiment is intended to transfer a rotary movement between two axles, which are arranged at an angle, no additional equipment is thus required for adapting the angles of the two axles in relation to each other for transferring a rotary movement.

According to another preferred embodiment of the invention, at least one of said axles includes an inner axle part and an outer axle part, wherein the inner and outer axle parts are displaceable in the longitudinal direction of the axle in relation to each other, wherein one of the axle parts is connected to the transmission element connected to the axle in such a way that, during said displacement of said one axle part in relation to the other axle part, said one axle part performs a displacement of the transmission element in relation to the second transmission element.

Thanks to an axle arranged in such a way, it is not necessary to displace the whole axle for obtaining the displacement of the transmission elements in relation to each other. Instead of displacing the whole axle, it is thus possible to displace the inner and outer parts of the axle in relation to each other. This means that the axle, if so desired, may be fixedly, i. e. non- displaceable in the longitudinal direction, mounted to one of its axle parts, and still permit displacement of the transmission element connected to the axle.

According to another preferred embodiment of the invention, at least one of said axles is provided with a spring member, which presses the transmission element connected to the axle against the second transmission element. Hereby it is ensured that the peripheral surfaces of the transmission elements abut each other when the transmission elements are displaced in relation to each other.

According to another preferred embodiment of the invention, the device includes means for automatic displacement of one of the transmission elements in relation to the other transmission element depending on the rotary speed of the axle connected to said one transmission element. Consequently, the transmission ratio between the rotary movements of the axles is automatically variable depending on the rotary speed of one of the axles.

According to a preferred embodiment of the invention, said displacement means includes at least one mass element, which is connected to the inner axle part and the outer axle part, and arranged to move, at an increasing rotation of the axle influenced by the centrifugal force, transversely to the longitudinal direction of the axle and, thereby, to displace the axle part connected to the transmission element in relation to the other axle part, whereby said one transmission element is displaced in the longitudinal direction of the axle towards the other transmission element. The use of mass elements, which in

this way move at an increasing rotation of the axle, provides a very simple, but at the same time efficient and reliable displacement of the transmission elements in relation to each other, and thus a variation of the transmission ratio between the rotary movements of the axles.

According to another preferred embodiment of the invention, the device includes a plurality of electromagnetic elements, wherein at least a first electromagnetic element is connected to the outer axle part and at least a second electromagnetic element is connected to the inner axle part, wherein the repelling force between the first and second electromagnetic elements is variable, wherein the electromagnetic elements are connected to the respective axle parts in such a way that an increase of the repelling force results in the electromagnetic elements being displaced from each other in the longitudinal direction of the axle and thus performing a displacement of the axle part connected to the transmission element in relation to the other transmission element, wherein said one transmission element is displaced in the longitudinal direction of the axle towards the other transmission element.

By means of the adjustment of the repelling force between the electromagnetic element as stated above, an accurate displacement of the transmission elements in relation to each other is enabled, and thus a variation of the transmission ratio between the rotary movements of the axles.

Further advantages, advantageous features and application fields of the invention appear form the remaining dependent claims, and from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS Below preferred embodiments of the invention are described by way of examples with reference to the drawings attached hereto, in which: Fig 1 is a perspective view of a device for transferring a rotary movement from a first axle to a second axle according to a first embodiment of the invention, Fig 2 is a cross-sectional view of the device illustrated in Fig 1 and shown in a first operational position, Fig 3 is a cross-sectional view of the device illustrated in Figs 1 and 2 and shown in a second operational position, Fig 4 is a plan view of a device for transferring a rotary movement from a first axle to a second axle according to a second embodiment of the invention, illustrating the device in a first operational position, Fig 5 is a plan view of the device illustrated in Fig 4 shown in a second operational position, Fig 6 is a plan view of a device for transferring a rotary movement from a first axle to a second axle according to a third embodiment of the invention, illustrating the device in a first operational position, and Fig 7 is a plan view of the device illustrated in Fig 6 shown in a second operational position.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION Figs 1-3 illustrate a device for transferring a rotary movement from a first axle 10 to a second axle 20 according to a first embodiment of the invention. The device includes a first transmission element 11, which is connected to the first axle 10 and arranged to rotate with the first axle 10. Furthermore, the device includes a second transmission element 21, which is connected to the second axle 20 and arranged to rotate with the second axle 20. According to this embodiment, the first transmission element is, as will be explained more closely below, attached to the first axle and the second transmission element is attached to the second axle. Of course, this is merely one possibility to arrange the transmission elements in such a way that they will rotate with the respective axle. Of course, the transmission elements do not necessarily need to be attached to the respective axle, but may for instance be connected to the respective axle via intermediate arrangements, for instance a further axle, in such a way that they rotate with the respective axle.

The first transmission element 11 has a substantially conical peripheral surface 12 and the second transmission element 21 has a substantially conical peripheral surface 22. The transmission elements are arranged in a such a way that the peripheral surface 12 of the first transmission element 11 abuts the peripheral surface 22 of the second transmission element 21 for transferring a rotary movement between the transmission elements 11,21. The material and the surface structure of the peripheral surfaces are preferably selected in such a way that a sufficient friction is obtained between the surfaces when they abut each other for enabling the transfer of the rotary movement between the transmission elements 11,21. Said selection of material and surface structure of the peripheral surfaces is easily made by a person skilled in this field, and will therefore

not be discussed any further. Possible examples of materials for the peripheral surfaces, which in no way is limiting to the invention, include various metals, plastics, kind of woods, but also textiles.

Preferably, the transmission elements 11,21 have the shape of a frustrum of a cone, as illustrated in figs 1-3, but it is of course also possible to design the transmission elements with another shape as long as the transmission elements have a respective substantially conical peripheral surface, which are arranged to abut each other. Furthermore, the first transmission element is, according to the embodiment illustrated in figs 1-3, provided with a cone angle which is substantially equal to the cone angle of the second transmission element. The word"cone angle" refers to the angle formed between a tangent to the conical peripheral surface of the transmission element and the centre axles of the frustrum of the cone.

According to this embodiment of the invention, the transmission elements 11,22 are two equal frustrums of a cone, so that when the whole width W of the peripheral surface 12 of the first transmission element 11 abuts the whole width W of the peripheral surface 22 of the second transmission element 21, the transmission ratio between the rotary movements of the transmission elements is 1: 1. This transmission ratio is illustrated in fig 1 and fig 2. Fig 2 also discloses a section A-A- A, from which appears that the circles contacting each other in the point A have equally radiuses, i. e. R2i=Rn, where R21 is the radius of the circle defined by the section A-A through the transmission element 21 and Rll is the radius of the circle defined by the section A-A through the transmission element 11.

Due to this relation between the radiuses the transmission ratio is 1: 1. This means that a rotary speed of x rounds per minute of the axle 10 corresponds to a rotary speed of x rounds per minute of the axle 20.

The transmission elements 11,21 are displaceable in relation to each other, preferably when the peripheral surfaces 12,22 abut each other. It is also possible to perform the displacement of the transmission elements 11,21 when the peripheral surfaces 12, 22 do not abut each other. However, the peripheral surfaces of the transmission elements 11,21 are arranged to abut each other during the remaining time for transferring a rotary movement therebetween. By displacing the transmission elements, the transmission ratio between the rotary movements of the axles 10,20 is variable. Fig 3 illustrates the transmission elements 11,21 in a position in which they are displaced in relation to each other. In the position illustrated in fig 3, the peripheral surfaces 12,22 thus does not abut each other over the whole of their widths W. Consequently, the circles contacting each other where the peripheral surfaces abut each other will have different radiuses and thus the transmission ratio between the rotary movements of the transmission elements will be differing from 1: 1. Fig 3 also illustrates the section B-B-B, from which appears that the circles contacting each other in point B do not have equally great radiuses, i. e. k*R21=R11, where R21 is the radius of the circle defined by the section B-B through the transmission element 21 and Rn, s the radius of the circle defined by the section B-B through the transmission element 11.

This means that the rotary speed of x rounds per minute of the axle 10 corresponds to a rotary speed of k*x rounds per minute of the axle 20.

The transmission elements 11,21 are thus displaceable in relation to each other. Preferably, the first transmission element 11 is displaceable substantially in the longitudinal direction of the first axle 10 and the second transmission element 21 is displaceable substantially in the longitudinal direction of the second axle 20.

As appears especially from fig 2 and fig 3, both the axles 10,20 include an inner axle part 13,23 and an outer axle 14,24

according to this embodiment of the invention. Alternatively, it is also possible to provide only one of the axles with an inner and an outer axle part and to provide the other axle, for instance in the shape of a solid axle in one piece. According to the embodiment illustrated in figs 1-3, however, both the axles have inner and outer parts. The inner 13,23 and outer 14,24 axles parts are displaceable in the longitudinal direction of the respective axle 10,20 in relation to each other, wherein one of the axle parts is connected to the transmission element connected to the axle in such a way that during a displacement of said one axle part in relation to the other axle part, said one axle part performs a displacement of the transmission element in relation the other transmission element.

According to the embodiment of the invention illustrated in figs 1-3, the inner axle part 13 of the first axle 10 is attached to the first transmission element 11. In a similar manner, the inner axle part 23 of the second axle 20 is attached to the second transmission element 21. Of course, it is instead possible to attach the outer axle parts to the respective transmission elements. Consequently, the inner axle part 13 of the first axle 10 performs, when it is displaced in relation to the outer axle part 14, the displacement of the first transmission element 11. In a similar manner, the inner axle part 23 of the second axle 20 performs, when it is displaced in relation to the outer axle part 24, the displacement of the second transmission element 21.

According to the embodiment of the invention illustrated in figs 1-3, the inner axle part 13,23 of the respective axle 10,20 is designed as a bar, which is reciprocating in an inner space 15, 25 of the outer axle part 14,24.

Preferably, at least one of said axles 10,20 is provided with a spring member, which presses the transmission element connected to the axle against the other transmission element.

According to the embodiment of the invention illustrated in figs

1-3, the second axle 20 is provided with a spring member 26 in the form of a helical spring, but also other kinds of spring members, such as for instance gas springs, are of course imaginable. In this case, the spring member 26 is however arranged in the inner space 25 in the outer axle part 24 and located around the inner axle part 23. The spring member 26 is thus located between the inner axle part 23 and the outer axle part 24.

Furthermore, the spring member 26 is connected to both the axles part 23,24 by attaching the spring member 26 at its one end to the inner axle part 23 by means of an attachment element 27, and by resting at its other end against a shoulder which is defined by a constriction 28 of the inner space 25 in the outer axle part 24. The spring member 26 is arranged to load the inner axle part 23, which is attached to the transmission element 21, towards the first transmission element 11. During the displacement of the first transmission element 11 in the longitudinal direction of the axle 10 towards or from the second transmission element 21, i. e. such as between the position illustrated in fig 2 and position illustrated in fig 3, the second transmission element 21 will thus be displaced in the longitudinal direction of the second axle 20 from or towards the first transmission element 11. During such a displacement the spring member 26 ensures by pressing the second transmission element 21 against the first transmission element 11 that the peripheral surfaces of the transmission elements abut each other.

According to the embodiment of the invention disclosed in figs 1-3, the axles 10,20 are arranged at an angle in relation to each other. Preferably, the axles 10,20 are arranged at a right angle in relation to each other, but also other angles are possible depending on the inclination of the peripheral surfaces of the transmission elements. In the case that the invention is applied to a motor vehicle, such as for instance a car, for transferring a

rotary movement from an output axle from the engine to a wheel axle, no special equipment is thus required for changing the angle between the output axle from the engine and the wheel axle. This is merely a possible field of use where this angle relation is an advantage, and the invention may of course be applied to many other various fields where the axles are lying at an angle in relation to each other.

According to a preferred embodiment of the invention, the device includes means for automatic displacement of one of the transmission elements in relation to the other transmission element depending on the rotary speed of the axle connected to said one transmission element.

Figs 1-3 illustrate how the device according to this embodiment of the invention includes such means, schematically indicated at 30, for automatic displacement of the first transmission element 11.

Preferably, said displacement means 30 includes at least one mass element 31. According to this embodiment of the invention, four mass elements are symmetrically provided around the axle 10, located in pairs opposite to each other on a respective side of the axle 10. The mass elements 31 are according to this embodiment designed as solid cylindrical rods, but may of course have an optional shape, since it is substantially only important which weight these elements have.

Each mass element is connected to the inner axle part and the outer axle part. The mass elements are provided to move, at an increasing rotation of the axle influenced by a centrifugal force, transversely to the longitudinal direction of the axle and thereby displace the axle part connected to the transmission element in relation to the outer axle part, whereby said one transmission element is displaced in the longitudinal direction of the axle towards the other transmission element.

According to this embodiment of the invention each mass element is, as appears from figs 2 and 3, via an arm 32 attached to the inner axle part 13 and via an arm 33 attached to the outer axle part 14. Each arm 32,33 is swingable around their both attachment points. As appears from fig 2 and fig 3 the arms 32, which are attached to the inner axle part 13, are furthermore attached to the inner axle part via the attachment elements 34, which extend from the interior of the outer axle part 14 to the outer side of the outer axle part 14 through grooves (not illustrated) provided therein. Furthermore, as mentioned previously above, the axle parts 13,14 are displaceable in relation to each other in the longitudinal direction of the axle 10.

Thanks to this construction, the mass elements 31 are thus movable transversely towards the longitudinal direction of the axle, i. e. reciprocating from and toward, respectively, the axle 10.

At an increasing rotation of the axle 10 the mass elements 31, influenced by the centrifugal force, will thus move transversely to the longitudinal direction of the axle outwardly from the axle 10. Hereby, the mass elements 31 will pull the arms 32,33 outwardly from the axle 10, which means that the inner axle part 13 is displaced in relation to outer axle part 14 and thus the first transmission element 11 is displaced in the longitudinal direction of the axle 10 towards the second transmission element 21. This course of action is illustrated by fig 2 and fig 3. Fig 2 illustrates a first operational condition, during which the axle 10 has no or a small rotation, wherein the mass elements 31 are located closely the axle 10. Fig 3 illustrates a second operational condition, during which the axle 10 has a higher rotation in comparison with the operational condition in fig 2, wherein the mass element 31 is located at a greater distance from the axle 10. Furthermore, the axle parts 13,14 are in fig 3 displaced in relation to each other, and the transmission elements 11,21 are displaced in relation to each other in comparison with fig 2. The weight of the mass elements 31 is selected in a suitable manner

so that a desired displacement of the axle parts 13,14 is achieved at a certain change of the rotary speed of the axle 10, and that thereby also a desired displacement of the transmission elements 11,21 in relation to each other is obtained.

Consequently, the transmission ratio between the rotary movements of the axles 10,20 is automatically changed depending on the rotary speed of the first axle 10.

From fig 2 and fig 3 also appears how the device, according to the embodiment of the invention disclosed in these figures, includes a spring member 35, which is arranged to counteract the displacement of the axle part 13 connected to the transmission element 11, caused by the influence of the centrifugal force to the at least one mass element 31, in relation to the other axle part 14 in such a way that, at a decreasing rotation of the axle 10 and thus a decreasing centrifugal force, the axle part 13 connected to the transmission element 11 is displaced in relation to the other axle part 14, whereby said one transmission element 11 is displaced in the longitudinal direction of the axle 10 from the second transmission element 21.

According to this embodiment of the invention, the spring member 35 is provided in the form of a helical spring, which in a similar manner as the spring 26 described above, is located around the inner axle part 13 in the inner space 15 of the outer axle part 14. Also other kinds of spring members, such as for instance gas springs, are of course imaginable. The helical spring 35 used according to this embodiment is however located in such a way that its one end abuts a shoulder defined by a constriction 36 in the outer axle part 14. The outer end of the spring is located to abut the attachment elements 34, which attach the mass elements 31 to the inner axle part 13 via the arms 32. At an increasing rotation of the axle 10 and thus a displacement of the inner axle part 13 in relation to the outer axle part 14 from the position disclosed in fig 2 to the position disclosed in fig 3, the spring 35 will thus be compressed and

thereby the spring force of the spring 35 will increase. At a decreasing rotation of the axle 10 and thus a decreasing centrifugal force to the mass elements 31, the inner axle part 30 will thus be displaced by the spring 35 in relation to the outer axle part 14, whereby the first transmission element 11 is displaced in the longitudinal direction of the axle 10 from the second transmission element 21, for instance as from the position disclosed in fig 3 to the position disclosed in fig 2. The spring force of the spring member 35 is suitably selected so that a desired displacement of the axle parts 13,14 is obtained and thus also a desired displacement of the transmission elements 11,21 in relation to each other at a certain change of the rotary speed of the axle 10 and thus a certain change of the centrifugal force to the mass elements 31. When selecting the spring force, the force, by which the mass elements will displace the axle parts 13,14 in relation to each other at different rotary speeds of the axle 10, is suitably considered.

With reference to fig 4 and fig 5 a device for transferring a rotary movement from a first axle 10 to a second axle 20 according to a second embodiment of the invention will now be described.

The device according to this second embodiment of the invention is substantially similar to the embodiment described above with reference to figs 1-3, and thus all parts of the device will not be described in detail. Instead it is referred to the description above of the first embodiment.

The only substantial difference over the first embodiment are the means which are provided for the displacement of the inner and outer axle parts 13,14 of the first axle 10 in relation to each other, and which means thus also control the displacement of the first transmission element 11 and the second transmission element 21 in relation to each other. According to this embodiment of the invention, the device includes a plurality of electromagnetic elements, for instance three elements 41,42, 43 which are illustrated in figs 4 and 5. At least a first

electromagnetic element is connected to the outer axle part 14 and at least a second electromagnetic element is connected to the inner axle part 13. As illustrated in figs 4 and 5, all the electromagnetic elements 41,42, 43 are according to this embodiment of the invention arranged as circular elements located around the outer axle part 14. According to this embodiment, one electromagnetic element 41 is attached to the outer axle part whereas two electromagnetic elements 42,43 are connected to the inner axle part 13. Hereby, the electromagnetic elements 42,43 may for instance, in a similar manner as the arms 32 are attached to the inner axle part 13 in the embodiment above, be attached to the inner axle part 13 via the attachment elements 34 running through grooves provided in the outer axle part 14. The repelling force between the electromagnetic elements 41,42, 43 is variable. This variation may be achieved by a suitable variation of the voltage or current depending on the properties of the electric equipment, which is connected to the electromagnetic elements 41,42, 43 for controlling their function.

The electromagnetic element 41 is thus connected to the outer axle part 14 and the elements 42,43 to the inner axle part 13.

Furthermore, like the embodiment above, the axle parts are displaceable in the longitudinal direction of the axle 10 in relation to each other, wherein the inner axle part 13 is moving within an inner space 15 defined in the outer axle part 14. At an increase of the repelling force between the electromagnetic elements 41,42, 43 the electromagnetic elements are displaced from each other in the longitudinal direction of the axle 10 and thus they perform the displacement of the inner axle part 13 attached to the transmission element 11 in relation to the outer axle part 14. Hereby, the first transmission element 11 is displaced in the longitudinal direction of the axle 10 towards the second transmission element 21. This course of action is illustrated from fig 4 to fig 5.

By means of a suitable variation of the repelling force between the electromagnetic elements 41,42, 43, the transmission ratio between the rotary movements of the axles 10,20 is thus variable as desired.

According to this embodiment of the invention, the device includes a spring member 35', which in a similar manner as the spring member 35 described above is arranged around the inner axle part 13 of the axle 10. The spring member 35 is in this case provided in the form of a helical spring, but also other kinds of spring members are imaginable. The spring member 35'is arranged to counteract the displacement, caused by the repelling force between the electromagnetic elements 41,41, 43, of the inner axle part 13 connected to the transmission element 11 in relation to the outer axle part 14 so that at a decreasing repelling force the inner axle part 13 connected to the first transmission element 11 will be displaced in relation to the outer axle part 14, whereby the first transmission element 11 is displaced in the longitudinal direction of the axle 10 from the second transmission element 21, as for instance from the position illustrated in fig 5 to the position illustrated in fig 4.

The helical spring 35'used according to this embodiment is located in such way that its one end abuts a shoulder, defined by a constriction of the outer axle part 14. The other end of the spring 35 is located to abut the attachment elements 34 (not visible in figs 4 and 5), which attach the electromagnetic element 43 to the inner axle part 13. At an increasing repelling force between the elements 41,42, 43 and thus a displacement of the inner axle part 13 in relation to the outer axle part 14 from the position disclosed in fig 4 to the position disclosed in fig 5, the spring 35'will thus be compressed and thereby the spring force of the spring 35'will increase. Consequently, at a decreasing repelling force between the elements 41,42, 43, the inner axle part 13 will be displaced by the spring 35'in relation to the outer axle part 14, whereby the first transmission element

11 is displaced in the longitudinal direction of the axle 10 from the second transmission element 21, for instance as from the position disclosed in fig 5 to the position disclosed in fig 4. The spring force of the spring member 35 is suitably selected in such a way that a desired displacement of the axle parts 13,14 is achieved, and thus also a desired displacement of the transmission elements 11,21 in relation to each other at a certain change of the repelling force between the elements 41, 42,43. When selecting the spring force, the force by which the electromagnetic elements will displace the axle parts 13,14 in relation to each other is suitably considered.

Figs 6 and 7 illustrate a device for transferring a rotary movement to a first axle 10 to a second axle 20 according to a third embodiment of the invention. This embodiment is substantially similar to the embodiment of the invention described above with reference to figs1-3, and all parts of the device will thus not be described in detail. This device includes two second axles 20, to which a rotary movement is transferable from the first axle 10. Both the axles 20 are designed as described above and have a respective transmission element 21. The two axles 20 are arranged substantially in alignment with each other, but with an opposite orientation so that each axle 20 has a respective transmission element 21 facing the transmission element 11 of the first axle 10. By this design driving at two different rotary directions of the axle 20 to which to rotary movement is transferred is possible while maintaining the same rotary direction of the axle 10 from which the rotary movement is transferred. This may for instance be used for driving a motor vehicle, for instance a car, in a direction forwardly and a direction rearwardly. By such a design driving in two different directions with the same variation of the transmission ratio in both directions is thus made possible The two second axles 20 are arranged to be movable in their longitudinal direction so that the axle 20 may be brought with

their transmission elements 21 to abutment against the first transmission element 11 of the axle 10. Fig 6 illustrates how the lower second axle 20 in the figure is located with its transmission element 21 to abutment against the first transmission element 11, wherein the rotary movement of the first axle 10 with the rotary direction illustrated by the arrow 51 is transferred to the second axle 20, which obtains a rotary movement with the rotary direction illustrated by the arrow 52.

When desired it is then possible to move the lower second axle 20 in the figure in its longitudinal direction from the first axle 10, wherein the transmission element 21 of the lower second axle in the figure is moved away from the abutment to the first transmission element 11.

At the same time the upper second axle 20 in figs 6 and 7 is moved in its longitudinal direction towards the first axle 10, wherein the transmission element 21 of the upper second axle in the figures is moved to abutment against the first transmission element 11. Fig 7 illustrates how the upper second axle 20 in the figure is located with its transmission element 21 in abutment against the first transmission element 11, wherein the rotary movement of the first axle 10 with the rotary direction illustrated by the arrow 51 is transferred to the second axle 20, which obtains a rotary movement with the rotary direction illustrated by the arrow 53, which is opposite to the direction disclosed by the arrow 52 in fig 6.

The invention is of course not in any way limited to the preferred embodiments described above, but a plurality of possibilities to modifications thereof should be apparent to an average person skilled in the art of the invention without deviating from the basic thought of the invention as this is defined in the claims attached hereto.

As mentioned initially, the device is well suited for use in motor vehicles, such as for instance cars, motor cycles, boats and air crafts. These examples are not to be considered as any limitation of the invention, but are merely some possible examples of areas where the present invention may be applied, which examples are mentioned for an illustrating purpose. The design of the device according to the invention enables manufacturing thereof in large as well as small dimensions, which makes the device well suited for transferring a rotary movement within a plurality of areas. Thanks to the simple construction of the device, it is possible to manufacture the device in relatively light materials and small dimensions, which enables use of the device also in for instance video-, cassette- and data tape recorders.

In the embodiments described above it has been described that the rotary movement has been transferred from the first axle 10 to the second axle 20. Of course an arrangement is possible where the rotary movement is transferred from the second axle 20 to the first axle 10 in the embodiments above. This may for instance be used in the case where there is a desire to obtain a constant rotary speed at the axle to which the rotary movement is transferred although the rotary speed varies at the axle from which a rotary movement is transferred. This is usable in wind power stations of different kinds where the input rotary movement depends on the wind force and therefore often varies, but where it is preferred to obtain a constant rotary speed to the generator of the wind power station.

Although it has been described in the embodiments above that the-peripheral surfaces 12,22 of the transmission elements 11, 21 are plane and abut each other under friction contact so that the rotary-movement may be transferred therebetween, this is of course no limitation to the invention. It is for instance also possible to provide peripheral surfaces 12,22 with teeth, wherein the peripheral surfaces are arranged to abut each other

in such a way that the teeth are in engagement with each other for transferring the rotary movement.

In the embodiments described above, the transmission elements 11,21 are illustrated with substantially equal dimensions. It is of course also possible to provide transmission elements 11,21 with different dimensions as long as the desired transmission ratios between the rotary movement of the axles are possible to achieve.

In the case that the device according to the invention is used in vehicles, one device per wheel, for instance four devices in cars, busses and the like, and two devices in cycles, motor cycles and the like, may advantageously be arranged. Hereby, the force, to be transferred to the driving wheels, may be distributed to a larger number of transmission elements than in the case where only one device according to the invention is provided in the vehicle.