Field of invention

The present invention relates to a fixation device for fixating a wheel with a bearing to a frame of an inline skate, a roller ski, a kick scooter, or a skateboard comprising a first nut having a first through-going bore along a first axis comprising a proximal part with a first inner diameter and a distal part with a second inner diameter.

Background of invention

Inline skates, roller skis, and kick scooters are getting more and more popular. There are many reasons. Some enjoy the exciting way to get exercise; others appreciate the opportunity to get out in the nature; and still others use them as effective means of transportation in the city.

The person exercising may get tired, someone enjoying the scenery might want to take a longer route than first decided, or the person on the way to work always wants to get there as fast as possible. In all these situations, an engine will be beneficial helping the user to get home despite the tired legs or to increase the speed.

The person on the way to work or home from work may want to get exercise one way but not the other way. Maybe the person does not want to arrive at the office in a sweaty condition.

Inline skates and kick scooters with engines are known. However, the engine for inline skates drive a driving wheel that is positioned to drive the rear wheel of the inline skate acting on the tread of the rear wheel in the same way as how two cogwheel act, where the axes of rotation of the cogwheel are parallel. With this construction, the rear wheel will be worn down much faster than the other wheels with the consequence that the rear wheel will rotate in the air without contact to the ground. Engines for kick scooters can act on the rear wheel through a belt. The rear wheel will not be worn down prematurely, but the frame of the kick scooters holding the rear wheel will have to be widened to allow for the belt next to the rear wheel. The same would be true for the roller ski, if an engine was mounted for driving a wheel through a belt.

Another problem with inline skates, roller skis, and kick scooters is their poor braking ability. Inline skates are often equipped with a plastic part extending behind the rear wheel. By putting down the heel and lifting up the toe of the inline skate the plastic part scratches the ground.

Some kick scooters have a brake in form of a plate on top of the rear wheel. By stepping on the plate, the plate is pressed against the tread of the wheel causing extra wear. In addition, the braking ability is not that great.

Summary of invention

The present disclosure relates to a fixation device for fixating a wheel with a bearing to a frame of e.g. an inline skate, a roller ski, a kick scooter, or a skateboard, where the fixation device can comprise a first nut having a first through-going bore along a first axis comprising a proximal part with a first inner diameter and a distal part with a second inner diameter, wherein the second inner diameter is smaller than the first inner diameter. The proximal part can have a first inner engagement element, such as an inner thread or an inner bayonet mount, configured when engaged with a

corresponding first outer engagement element to prevent displacement along the first axis between the first inner and the first outer engagement elements.

The distal part can have a receiving part, where the receiving part is configured to receive a first tool inserted through the proximal part of the first through-going bore, so that the first nut and the first tool cannot rotate in relation to each other when the receiving part has received the first tool. The receiving part can have any form as long as a rotational movement can be transferred between the receiving part and the corresponding key.

This first nut has the advantage that the first nut can be held by a key, which fits the receiving part, from both sides - from the proximal side or from the distal side. With an item (e.g. a screw) that allows a key access to the receiving part from the proximal part of the first nut, the first nut can be held and kept from rotating so that the first nut and the item can be engaged to each other in situations, where it is otherwise impossible to hold the first nut like in a situation where the first nut is positioned e.g. in a bearing, or in a cavity, where there is no access from the cavity side of first nut.

That the first inner engagement element, such as an inner thread or an inner bayonet mount, is configured to engage with a corresponding first outer engagement element to prevent displacement along the first axis between the first inner and the first outer engagement elements, means that the first inner engagement element and the first outer engagement element when engaged cannot be pulled away from each other or pushed closer to each other along the first axis.

The second inner diameter is preferably smaller than the first inner diameter so that the first inner diameter with the first inner engagement element can receive the item and so that the item can still allow a key access to the receiving part from the proximal part of the first nut.

In an embodiment of the present disclosure of the fixation device, the first nut can have a flange extending outward in the radial direction of the first through-going bore, preferably the flange is positioned at the distal part of the first nut, more preferably the flange flushes with a distal end of the first nut at the distal part of the first nut, the outside of the first nut can be tapered or conical, or the outside of the first nut can have a second outer engagement element.

The flange or the tapered or conical outer shape of the first nut will keep an item with an opening placed around the first nut in place so that the item cannot slide off the first nut when the first nut is positioned in the opening and the first nut is mounted using the first inner engagement element.

If the outer shape of the first nut is tapered or conical, an inner opening of the item is advantageously also tapered or conical preferably with the same inclination.

The second outer engagement element can e.g. be a thread or a bayonet mount, where the first nut can be engaged in an opening. In an embodiment of the present disclosure of the fixation device, the fixation device can comprise a bearing with an inner opening, where the first nut having a flange is positioned in the inner opening, the inner opening is tapered or conical, and the outside of the first nut being tapered or conical is positioned in the tapered or conical inner opening, preferably the inclinations of the inner opening of the bearing and of the outside of the first nut are substantially identical, the inner opening has a second inner engagement element correspondingly fitting the second outer engagement element of the first nut, and the second inner engagement element and the second outer engagement element are in engagement with each other, the first nut is press-fit into the bearing, the first nut is positioned into the inner opening of the bearing and the first nut and bearing is glued together, and/or the inner opening of the bearing is the first through-going bore of the first nut.

The flange, the second outer engagement element or the tapered or conical outside of the first nut will keep the bearing in place so that the bearing cannot slide off the first nut when the first nut is positioned in the inner opening and the first nut is mounted using the first inner engagement element.

If the first nut is press-fit into or glued to the bearing, the bearing cannot come off the first nut.

In an embodiment of the present disclosure of the fixation device, the fixation device can comprise a first screw with an first outer engagement element correspondingly fitting the first inner engagement element of the first nut, where the first screw has a second through-going bore configured to allow access for the first tool to engage with the receiving part when the first inner engagement element and the first outer engagement element are in engagement with each other.

With the second through-going bore, the first screw has a means to allow access for the first tool to engage with the receiving part of the first nut through the proximal part of the first nut. This way, the first nut can be held and kept from rotating so that the first nut and the first screw can be engaged to each other in situations, where it is otherwise impossible to prevent the first nut from rotating together with the first screw like in a situation where the first nut is positioned e.g. in a bearing, or in a cavity, where there is no access from the cavity side of first nut. In an embodiment of the present disclosure of the fixation device, the fixation device can be configured such that when the first nut is positioned in the bearing, and the bearing is positioned in an indentation in the side of a wheel having a first holding mechanism at the centre of the wheel, and the first nut and the first screw are in engagement with each other through a first opening of a frame of an inline skate, a roller ski, a kick scooter, or a skateboard thereby fixating the wheel with the bearing to the frame, the first through-going bore and the second through-going bore provide direct access to the first holding mechanism of the wheel.

With this embodiment of the fixation device, an inline skate, a roller ski, a kick scooter, or a skateboard without an engine can be transformed into an inline skate, a roller ski, a kick scooter, or a skateboard that can receive a driving shaft driven by an engine and/or a braking shaft connected to a brake. A wheel with the fixation device is thus prepared to be driven by an engine in a way that will not wear the tread of the wheel and without the need of replacing the frame of the inline skate, the roller ski, or the kick scooter, and the wheel with the fixation device is also prepared to receive an efficient brake.

The engine can have a driving element that is a freewheel. The engine through the driving element can drive the driving shaft and the wheel forward and the wheel can still rotate even though the engine is not rotating or driving the wheel. The freewheel can have different designs and many designs are well known within the art.

The present disclosure relates to a wheel kit comprising

two wheel rim parts configured to be positioned on each side of a wheel for inline skates, roller skis, and/or kick scooters, and to engage with the wheel when the two wheel rim parts are connected to each other or to each side of the wheel,

a wheel for inline skates, roller skis, and/or kick scooters, having a centre metal piece moulded in the centre of the wheel, or

a wheel for inline skates, roller skis, and/or kick scooters comprising a rim totally, or at least substantially, made of metal,

where at least one, preferably both, of the wheel rim parts, the centre piece, or the rim comprises a first holding mechanism. A wheel for inline skates, roller skis, and/or kick scooters normally comprises a non- inflatable tyre made of hard rubber or plastic, preferably polyurethane, surrounding a rim made of plastic or metal. The rim has a standard opening forming a cylindrical cavity for receiving two bearings one at each end of the standard opening. In the middle of the standard opening, the diameter of the standard opening is a little smaller like fixed spacer creating a contact surface to keep the bearings at the right position. A bolt and nut through the two bearings will hold the wheel to the frame in such a way that the wheel can rotate in relation to the frame.

The two wheel rim parts preferably has the size of the standard opening so that the wheel rim parts can be pressed into the standard opening one from each end of the standard opening.

The first holding mechanism of one or both of the wheel rim parts, the centre piece, or the rim can be engageable with a second holding mechanism of a driving shaft driven by an engine or of a braking shaft connected to a brake. When a wheel for inline skates, roller skis, and/or kick scooters having an engine driving the wheel through a driving shaft as presented according to this invention is worn out and needs to be replaced, the two wheel rim parts can be mounted on each side of an ordinary wheel for inline skates, roller skis, and/or kick scooters without the bearings. The two wheel rim parts can be kept in place by being screwed together or by having corresponding male and female connectors that will stick to each other when snapped together. Alternatively, the worn out wheel can be replaced by a wheel having a centre metal piece moulded in the centre of the wheel, or a wheel comprising a rim made of metal, where the centre of the wheel has the first holding mechanism.

Using the two wheel rim parts, an ordinary wheel for inline skates, roller skis, and/or kick scooters can be transformed so that the transformed wheel can be controlled by a driving shaft driven by an engine and/or by a braking shaft connected to a brake.

With any of these wheels replacing the worn-out wheels, the inline skates, roller skis, and/or kick scooters with an engine driving the wheel through a driving shaft at the centre of the wheel can be used again. The first holding mechanism can preferably be an opening in the form of a hex key or a torx. Any shape of the first holding mechanism that can transfer a rotational movement is possible, but it will preferable that the mechanism is not pointed but cylindrical with a constant diameter but with a non-circular cross-section. The first holding mechanism having the shape of a phillips key or a pozidriv key is possible, but the corresponding driving shaft will get disengaged if moved away from the first holding mechanism, since both the phillips and pozidriv keys are pointed. Torx and hex key are substantially cylindrical with an uneven cross-section. Torx can transfer more momentum than a hex key of the same size since the direction of the normal of the plane of contact between the first and second holding mechanisms is closer to the direction of rotation for the torx than for the hex key.

In an embodiment of the present disclosure of the wheel kit, at least one, preferably both, of the two wheel rim parts can have one or more edges or knives on the side of the wheel rim part configured to face the wheel so that the one or more edges is/are cut into or squeezes the wheel when the two wheel rim parts are connected to each other. Alternatively or in addition, the two wheel rim parts can be glued to the cylindrical cavity of the wheel.

The knives or edges will cut into the edges of the fixed spacer of the cylindrical cavity of the standard opening and the wheel rim parts cannot accidentally slide especially not in the rotational direction relative the rim of the wheel.

In an embodiment of the present disclosure of the wheel kit, the one or more edges can extend substantially radially.

With the one or more knives or edges extending substantially radially, the rotational force from the driving shaft onto the wheel rim parts and then from the wheel rim parts will be acting on the rim of the wheel substantially perpendicular to the direction of the edges making it impossible that the wheel rim parts will accidentally slide relative the rim of the wheel.

In an embodiment of the present disclosure of the wheel kit, at least one, preferably both, of the wheel rim parts can have an indentation configured for receiving a bearing with the first nut presented above and/or below positioned in an inner opening of the bearing.

The wheel can be suspended by the frame on both sides of the wheel, and the wheel will need a bearing on each side. When the wheel is suspended on both sides, the result will be a stable construction, where the stress on the bearings are not so high. The wheel can be suspended by the frame on one side of the wheel, and the wheel will need a bearing on only one side. Generally, the wheel will be a little easier to exchange, since only one bolt and nut need to be detached and attached again.

Alternatively, the wheel rim parts have no indentation, and the wheel rim parts can be connected to each other and positioned in the cylindrical cavity of the standard opening of the wheel in the middle of the cylindrical cavity in such a way that the bearings can be placed in the cylindrical cavity and not in the indentation of the wheel rim parts. If the wheel rim parts do not extend outside the fixed spacer so that the bearing is able to contact the contact surface of the fixed spacer, then the advantage will be that standard bearings for wheels for the inline skates, roller skis, kick scooters and/or skateboards can be used resulting in lower production costs.

In an embodiment of the present disclosure of the wheel kit, at least one, preferably both, of the two wheel rim parts or the centre piece can be made of metal.

Rim parts or centre pieces made of metal will be strong and durable. The first holding mechanism is exposed to strong forces and momentums by the second holding mechanism of the driving shaft that may eventually wear down the first holding mechanism if the material is too soft and/or too brittle. When the rim parts or the centre pieces are made in metal the first holding mechanism will be very durable. When the rim parts are made of metal the one or more edges can more easily cut into the wheel and the one or more edges can be made sharper so that the edges can cut further into the wheel.

The present disclosure relates to a device that can comprise any or all of

the fixation device according to any of the preceding claims,

a wheel having a first holding mechanism at the centre of the wheel, and a shaft having at a distal end a second holding mechanism that is engageable with the first holding mechanism,

wherein the first through-going bore and the second through-going bore are configured so that the first holding mechanism of the wheel is reachable by the second holding mechanism of the shaft through the first through-going bore and the second through-going bore, and so that the shaft can freely rotate within the first and second through-going bores.

By the first and/or the second through-going bores, the fixation device gives access for the second holding mechanism of the shaft to the first holding mechanism at the centre of the wheel. In this way, the rotational position and/or velocity of the wheel can be controlled by the shaft.

In an embodiment of the present disclosure of the device, the wheel can comprise two wheel rim parts one on each side of the wheel, wherein

at least one of the wheel rim parts comprises the first holding mechanism, and

the two wheel rim parts are connected to each other, e.g. by screws, to keep the wheel in between.

In an embodiment of the present disclosure of the device, at least one of the two wheel rim parts can have one or more edges on the side of the wheel rim part facing the wheel so that the one or more edges is/are cut into or squeezes the wheel when the two wheel rim parts are connected to each other.

The two wheel rim parts can be connected directly to each other or indirectly to each other, where two wheel rim parts e.g. both are connected to the wheel.

In an embodiment of the present disclosure of the device, the two wheel rim parts can be made of metal.

In the above three independent or interdependent embodiments of the wheel rim parts, the wheel rim parts will have all the advantages and all the possible variations as pointed out for wheel rim parts above In an embodiment of the present disclosure of the device, a metal piece comprising the first holding mechanism can be moulded into the centre of the wheel.

This embodiment of the wheel for inline skates, roller skis, or kick scooters is an alternative to the wheel with the two wheel rim parts connected on each side of a standard wheel for inline skates, roller skis, or kick scooters. The wheel with the metal piece comprising the first holding mechanism will be cost-effective to produce and no manual labour to transform a standard wheel into a wheel with the first holding mechanism in the centre is necessary.

In an embodiment of the present disclosure of the device, the device can comprise a bearing with an inner opening, wherein the first nut of the fixation device is placed in the inner opening of the bearing, and wherein the bearing is positioned in an indentation in one side of the wheel and/or in one of the two wheel rim parts.

With the first nut placed in the inner opening of the bearing, and the bearing positioned in an indentation in one side of the wheel and/or in one of the two wheel rim parts, it is clear that the solution presented above to how to prevent the first nut from rotating when connected to the first screw is necessary.

In an embodiment of the present disclosure of the device, the first screw positioned in a first opening of a frame of an inline skate, a roller ski, a kick scooter, or a skateboard can be engaged with the first nut placed in the inner opening of the bearing.

With the first nut placed in the inner opening of the bearing, and the bearing positioned in an indentation in one side of the wheel and/or in one of the two wheel rim parts, it is clear that the solution presented above to how to prevent the first nut from rotating when connected to the first screw is necessary. This way, the first and the second through-going bores of the first nut and the first screw will give access for a driving shaft or a braking shaft with the second holding mechanism to the first holding mechanism of the wheel.

In an embodiment of the present disclosure of the device, the device can be a driving device and the shaft is a driving shaft, and the driving device can comprise an engine connected to a proximal end of the driving shaft for driving the driving shaft. The engine will through the driving shaft having the second holding mechanism that can engage with the first holding mechanism at the centre of the wheel act at the centre of the wheel for driving the wheel without wearing prematurely the tread of the wheel.

The engine can be an electric engine driven by a battery, and the engine can be transformed to an electric generator, regeneratively braking the wheel and at the same time charging the battery. The transformation of the electric engine into an electric generator is controlled by an electric circuit controlling the electric engine and can easily be activated by pressing a brake button. Using regenerative braking, the engine can be used to effectively brake inline skates, roller skis, and/or kick scooters, which is much needed especially for the inline skates but also for roller skis and kick scooters, and at the same time extending the time until the battery is flat and needs to be charged.

The regenerative braking can be set to different levels of regeneration/braking making a training session a little harder and at the same time charging the battery.

In an embodiment of the present disclosure of the device, the device can be a braking device and the shaft is a braking shaft, and the braking device can comprise a brake connected to a proximal end of the braking shaft for braking the driving shaft.

The brake will simplify retardation.

Preferably, two brakes preferably connected to each other by the torque arm can be acting on two wheels of the same inline skate for increasing the braking ability.

In an embodiment of the present disclosure of the device, the brake can be a drum brake, a disc brake, a magnetic brake, an induction brake, a band brake, or a regenerative brake.

A drum brake has the advantage of having a cover that protects the braking parts from dirt and water that could limit the braking ability at least occasionally. Especially, the regenerative brake will be advantageous, since a battery can be charged, where the battery is used for providing power to an electric engine driving the wheel, or to light so the user can see or be seen in the dark.

The present disclosure relates to a first engine kit for an inline skate, a roller ski, a kick scooter, and/or a skateboard that can comprise:

a driving shaft,

an engine configured to be mounted to a frame of an inline skate, a roller ski, a kick scooter, or a skateboard, comprising a driving element configured for driving the driving shaft, and

a fixation device as described above and/or below.

With such a first engine kit an inline skate, a roller ski, a kick scooter, and/or a skateboard can be transformed into an inline skate, a roller ski, a kick scooter, and/or a skateboard driven by an engine acting on the centre of the wheel resulting in a much more reliable propulsion with very low friction in the transmission of rotational energy from the engine to the wheel.

The first and the second through-going bores of the first nut and the first screw of the fixation device are configured so that the driving shaft can freely rotate within the first and second through-going bores.

Depending on whether the kit is for an inline skate, a roller ski, a kick scooter, or a skateboard the parts of the kit will have different configurations. The skilled person will understand how the kit should be configured to fit an inline skate, a roller ski, a kick scooter, or a skateboard.

In an embodiment of the present disclosure of the first engine kit, the engine can comprise a transmission device and the first engine kit can comprise two driving shafts so that the engine with the transmission device can have two driving elements so that the engine is configured to drive two parallel driving shafts, where the distance between the two driving elements corresponds to the distance between two wheels of an inline skate. With two driving elements or driving shafts acting on two different wheels, the stress on each driving shaft, on each first and second holding mechanism, and on each wheel will be half the stress as when the engine is only acting on one wheel.

Unevenness in the supporting surface of the inline skate may cause the driven wheel to loose contact with the support and start spinning in the air. This is less likely with two wheels being driven by the engine, especially if the transmission device is designed so that the two driven wheels always have the same rotational speed.

In an embodiment of the present disclosure of the first engine kit, the transmission device can comprise two transmission parts pivotable to each other around an axis parallel with the rotation axis of the driving elements.

The axis will preferably coincide with the rotational axis of a first rotating wheel or first cogwheel in the transmission device. The two neighbouring cogwheels will then move along the periphery of the first cogwheel.

With the two transmission parts pivotable to each other around an axis parallel with the rotation axis of the driving elements, the distance between the two driving elements or driving shafts can be adjusted so that the transmission device for driving two driving elements can fit any inline skate irrespective of the distance between the wheels.

The present disclosure relates to a method of installing an engine and/or a brake on an inline skate, a roller ski, a kick scooter, or a skateboard having a frame with a first opening holding a first wheel, the method comprising the steps of

removing a first wheel from the frame,

positioning a first nut as described above and/or below in a distal end of an inner opening of a bearing,

positioning the bearing in a first indentation of a second wheel having a first holding mechanism at the centre of the wheel, or removing one or two bearings from a standard opening of the first wheel, connecting two wheel rim parts to each other on each side of the first wheel in the standard opening, where at least one of the two wheel rim parts has a first holding mechanism at the centre of the wheel rim part, and positioning the bearing in a second indentation of the first wheel and/or of at least one of the wheel rim parts,

engaging the first nut and a first screw as described above and/or below with the first opening of the frame between the first nut and the first screw, and

positioning a driving shaft or braking shaft having at a distal end a second holding mechanism that is engageable with the first holding mechanism through the second through-going bore of the first screw and the first through-going bore of the first nut to engage with the first holding mechanism, the driving shaft is driven by the engine or the braking shaft is braked by the brake.

The wheel rim parts may be formed to comprise a bottom and sidewalls of the second indentation.

Instead of reusing the first wheel especially if the first wheel is worn out, another standard wheel can be adapted by connecting two wheel rim parts to each other on each side of the other standard wheel in the standard opening, or a second wheel having a first holding mechanism at the centre of the wheel can be used to replace the first wheel. The first holding mechanism can be formed in a piece of e.g. metal or some other hard and durable material, where the piece is moulded into the rim or the first holding mechanism can be formed in the rim. It might be faster and more cost-effective due to a shorter assembling time to replace the first wheel with the second wheel than to connect two wheel rim parts to each other on each side of another new standard wheel for inline skates, roller skis, or kick scooters.

Using this method an inline skate, a roller ski, a kick scooter, or a skateboard without an engine and/or without an efficient brake can be equipped with an engine and/or a brake acting on the centre of the wheel of the inline skate resulting in a much more reliable propulsion with very low friction in the transmission of rotational energy from the engine to the wheel and /or resulting in a much more reliable and more effective retardation of the speed.

In an embodiment of the present disclosure of the method, wherein during engaging the first nut with the first screw, a first tool can be inserted through the second through- going bore of the first screw and the proximal part of the first through-going bore of the first nut to engage with the receiving part, and a second tool can be engaged with the first screw preventing relative rotation, and rotating the first tool and the second tool in relation to each other.

Since the first nut is unreachable due to the wheel and the frame when the first screw and the first nut are about to be screwed together or in any other way connected to each other, the first tool engaging the receiving part through the second through-going bore and the first through-going bore this method serves as a very good solution to the problem.

The present disclosure relates to a second engine kit for an inline skate, a roller ski, a kick scooter, or a skateboard having a frame, the engine kit comprising:

an engine configured to be mounted to a frame of an inline skate, a roller ski, a kick scooter, or a skateboard, comprising a driving element configured for driving a driving shaft,

a wheel for inline skates, roller skis, and/or kick scooters, having a first holding mechanism at the centre of the wheel,

a driving shaft having a proximal end configured to be driven by the engine and a distal end having a second holding mechanism engageable with the first holding mechanism,

a second fixation device, comprising:

a second nut having a first through-going bore with a first inner engagement element,

a first screw as described above and/or below with an first outer engagement element correspondingly fitting the first inner engagement element of the second nut, where the first screw has a second through- going bore,

where the first through-going bore and the second through-going bore are configured to rotatingly receive the driving shaft,

a drill bit for drilling a hole through the frame of the inline skate, the roller ski, or the kick scooter, and through the second nut, and

a pin for being inserted in the hole drilled by the drill bit to prevent the second nut from rotating relative the frame. Such a second engine kit can be assembled so that an inline skate, a roller ski, a kick scooter, and/or a skateboard can be transformed into an inline skate, a roller ski, a kick scooter, and/or a skateboard driven by an engine acting on the centre of the wheel resulting in a much more reliable propulsion with very low friction in the transmission of rotational energy from the engine to the wheel.

The expression“rotatingly receive” means in this connection that the first through-going bore and the second through-going bore are configured to receive the driving shaft so that the driving shaft can freely rotate in the first and second through-going bores without transferring the rotational motion to the second nut or to the first screw

As mentioned above, the problem is to prevent the first nut or the second nut from rotating when engaged with the first screw. By drilling holes in the frame and into the second nut and inserting the pin in the drilled hole, the second nut cannot rotate and the first screw can be connected to the second nut. The drill bit is preferably fastened in a chuck of a drill for drilling the hole(s). The drill may or may not be part of the kit.

Since most if not all people have drill bits of different sizes at home, the kit could come without the drill bit, and the user would still be able to assemble the kit on an inline skate, a roller ski, a kick scooter, or a skateboard.

Depending on whether the kit is for an inline skate, a roller ski, a kick scooter, or a skateboard the parts of the kit will have different configurations. The skilled person will understand how the kit should be configured to fit an inline skate, a roller ski, a kick scooter, or a skateboard.

In an embodiment of the present disclosure of the second engine kit, the second engine kit can comprise:

a bearing with an inner opening for receiving the second nut, wherein the wheel is configured to receive the bearing.

The second nut is inserted in the bearing. A bearing has an inner ring and an outer ring with balls in between so that the inner ring and the outer ring can rotate independently in relation to each other. Instead of drilling the holes into the second nut, the holes can be drilled into the inner ring with the same result. In an embodiment of the present disclosure of the second engine kit, the second engine kit can comprise:

- a frame for an inline skate, a roller ski, a kick scooter, or a skateboard, wherein the second nut and/or the bearing has a third holding mechanism, and the frame has a fourth holding mechanism, wherein the third holding mechanism and the fourth holding mechanism are engagable with each other to prevent rotation of the second nut relative the frame when the second nut and/or the bearing is assembled with the frame.

By replacing a standard frame that is part of a inline skate, roller ski, or kick scooter with the frame having a fourth holding mechanism that can engage with the third holding mechanism of the second nut and/or the bearing, the second nut cannot rotate and the first screw can be connected to the second nut.

In an embodiment of the present disclosure of the second engine kit, the second engine kit can comprise a pair of wheel rim parts as described above and/or below.

The advantages of the wheel rim parts have already been mentioned.

The second kit can comprise any of the features of the first engine kit.

The present disclosure relates to a pair of wheel rim parts as described above and/or below. The wheel rim parts can have all the features and all corresponding advantages as described in connection with the wheel rim parts above and/or below.

Depending on whether the wheel rim parts are for an inline skate, a roller ski, a kick scooter, or a skateboard the parts of the wheel rim parts will have different

configurations, and/or sizes. The skilled person will understand how the wheel rim parts should be configured to fit the wheels of an inline skate, a roller ski, a kick scooter, or a skateboard.

The present disclosure relates to a braking kit as described above and/or below where the driving shaft is replaced by a braking shaft, and the engine of the first engine kit or the second engine kit for driving a driving shaft is replaced with a brake for braking a braking shaft. In the first engine kit or the second engine kit, the kits comprise engines that can drive the driving shafts. In the present braking kit, the brake acts on the braking shaft in the same way as the engine acts on the driving shaft. The braking shaft has at its distal end the second holding mechanism that can engage with the first holding mechanism at the centre of the wheel. The brake acting on the braking shaft can thus brake the wheel.

The present disclosure relates to an inline skate, a roller ski, a kick scooter, or a skateboard comprising a frame with a first opening, wherein the first engine kit as described above and/or below or the second engine kit as described above and/or below and/or the braking kit as described above and/or below is/are assembled, wherein the assembled first engine kit or the assembled second engine kit is mounted to the frame for driving the wheel through a driving shaft as described above and/or below and/or the assembled braking kit is mounted to the frame for braking the wheel through a braking shaft as described above and/or below.

The inline skate, the roller ski, or the kick scooter with the engine and/or brake connected the frame will have the benefit of an engine and/or a brake that acts through the driving shaft and/or the braking shaft through the second and first holding mechanisms on the centre of the wheel. The tread on the wheel will not get worn prematurely, the engine can act on the wheel with low friction, and the brake will be efficient.

In an embodiment of the present disclosure of the inline skate, wherein two braking kits are assembled and, wherein the two assembled braking kits are mounted to the frame for braking two wheels independently.

Two brakes acting on the same inline skate will increase safety. If one brake gets too hot, is worn out, or the wheel on which the brake acts has a too small diameter to reach the ground e.g. due to the wheel being worn, then the brake acting on the other wheel will bring the inline skate to a halt.

A method of installing an engine and/or a brake on an inline skate, a roller ski, a kick scooter, or a skateboard having a frame with a first opening holding a first wheel, the method comprising one or more of the steps of removing the first wheel from the frame,

positioning a third nut in an inner opening of a bearing, where the third nut has a first through-going bore with an first inner engagement element, positioning the bearing in a first indentation of a second wheel having a first holding mechanism at the centre of the wheel, or removing one or two bearings from a standard opening of the first wheel, connecting two wheel rim parts to each other on each side of the first wheel in the standard opening, where at least one of the two wheel rim parts has a first holding mechanism at the centre of the wheel rim part, and positioning the bearing in a second indentation of the first wheel and/or of at least one of the wheel rim parts,

positioning the first wheel or the second wheel with the bearing and the third nut at the frame,

drilling holes through the frame and through the third nut and/or an inner ring of the bearing,

positioning rods in the drilled holes, where the rods has substantially the diameter of the drilled holes, preventing rotation of the third nut and the inner ring of the bearing relative the frame,

engaging the third nut with a first screw as described above or below with the first opening of the frame between the third nut and the first screw, and positioning a driving shaft or a braking shaft having at a distal end a second holding mechanism that is engageable with the first holding mechanism through the second through-going bore of the first screw and the first through-going bore of the third nut to engage with the first holding mechanism, the driving shaft is driven by the engine or the braking shaft is braked by the brake.

The third nut will preferably have an outer shape that fits in the inner ring of the bearing. Preferably the outer shape of the third nut will be cylindrical. The third nut and the bearing can be press-fit together or the third nut can have the flange or the tapered shape of the first nut with the same advantages.

The wheel rim parts may be formed to comprise a bottom and sidewalls of the second indentation, or the wheel rim parts form only the bottom of the second indentation, and the sidewalls of the second indentation are formed by the standard opening of the first wheel. The diameter of the second indentation when the standard opening forms the sidewalls allows standard bearings to be used, which will be cost effective. If the bearings removed from the first wheel in the first place are in good condition, the bearings can be reused and positioned in the second indentation.

Instead of reusing the first wheel by connecting two wheel rim parts to each other on each side of the first wheel in the standard opening, a second wheel having a first holding mechanism at the centre of the wheel can be used to replace the first wheel. If the first wheel is already worn out, it will be easier to replace the first wheel with the second wheel than to connect two wheel rim parts to each other on each side of another new standard wheel for inline skates, roller skis, or kick scooters.

Using this method an inline skate, a roller ski, a kick scooter, or a skateboard without an engine and/or without an efficient brake can be equipped with an engine and/or a brake acting on the centre of the wheel of the inline skate resulting in a much more reliable propulsion with very low friction in the transmission of rotational energy from the engine to the wheel and /or resulting in a much more reliable and more effective retardation of the speed.

Description of Drawings

The invention will in the following be described in greater detail with reference to the accompanying drawings.

Figure 1 shows an engine driven inline skate,

Figure 2a shows an exploded view of a fixation device comprising a first nut and a first screw fixating a bearing to a frame,

Figure 2b shows a cross-section of the first nut,

Figure 2c shows the fixation device, where the first nut and the first screw are fixated to each other,

Figure 2d shows a bayonet mount, Figure 3a shows a standard wheel for an inline skate, a roller ski, a kick scooter, or a skateboard,

Figure 3b shows the standard wheel with rim parts,

Figure 3c shows a cross-section of the wheel in Fig. 3b,

Figure 3d shows a rim part,

Figure 3e shows the rim part in a perspective view,

Figure 3f shows a cross-section of the rim part having a first holding mechanism in Fig. 4a,

Figure 3g shows another embodiment of the wheel with a plate having the first holding mechanism,

Figure 3h shows a piece having the first holding mechanism,

Figure 4a shows a cross-section of the wheel connected to a frame, and an engine about to the connected to the first holding mechanism of the wheel

Figure 4b shows a fraction of a frame with an engine mounted to the frame of a roller ski a kick scooter, or a skateboard for driving the wheel,

Figure 5a shows a brake

Figure 5b shows the brake mounted to the inline skate,

Figure 6 shows a transmission for transmitting the rotational movement of the engine to two driving shafts,

Figure 7a shows an embodiment of a second nut

Figure 7b shows the second nut when seen from the left in in Fig. 7a, and Figure 7c shows a fragment of a modified frame 6” for an inline skate, a roller ski, a kick scooter, or a skateboard.

Detailed description of the invention

The invention is described below with the help of the accompanying figures. It would be appreciated by the people skilled in the art that the same feature or component of the device is referred with the same reference numeral in different figures.

Fig. 1 shows an inline skate 2 comprising a boot 4 and a frame 6 holding in this case four wheels 8. The number of wheels could be from two to five and even six. The inline skate also comprises an engine unit 10 and a battery 12 supplying electrical energy to the engine unit through a conductor or an electrical cable 14.

The inline skate also comprises a handheld element (not shown) like a handle connected to the engine unit or to the battery for controlling the power output of the engine unit, e.g. by controlling/reducing the voltage level to the engine unit from the battery.

Fig. 2a shows a first screw 22, a part of the frame 6 with a first opening 24, a first nut 26 to be positioned in an inner opening 27 of a bearing 28, like a ball bearing.

A proximal end and a distal end in Fig. 2a and in all subsequent drawings are to the left and to the right, respectively. The expressions proximal end and distal end are used for clarity purposes.

The first nut 26 has a first through-going bore 30 along a first axis 32, where the first nut comprises a proximal part 34 with a first inner diameter and a distal part 36 with a second inner diameter, where the second inner diameter is smaller than the first inner diameter. The proximal part 34 has a first inner engagement element 38, which can e.g. be an inner thread or an inner bayonet mount.

The first screw 22 has a second through-going bore 40 and at a distal end 42 of the first screw a first outer engagement element 44, where the first outer engagement element 44 can e.g. be an outer thread or an outer bayonet mount. The first outer engagement element 44 and the first inner engagement element 38 are engageable with each other.

The first screw 22 has a first receiving part 46 for receiving e.g. a wrench/spanner or an adjustable spanner so that the tool can rotate or prevent rotation of the first screw. The first receiving part 46 can have other embodiments to receive other types of tools.

Fig. 2b shows a cross-section of the first nut 26. The distal part 36 has a second receiving part 48, where the second receiving part is configured to receive a first tool inserted through the proximal part 34 of the first through-going bore, so that the first nut and the first tool cannot rotate in relation to each other when the second receiving part has received the first tool. In the shown embodiment, the second receiving part 48 is configured to receive a hex key. However, the second receiving part 48 could also be configured to receive any type of key like e.g. a torx key, a phillips key, pozidriv key, or a slot screwdriver.

When the first nut 26 and the first screw 22 are assembled a suitable tool like a wrench engage with the first receiving part 46, and another suitable tool like a hex key is inserted through the second through-going bore 40 and the first through-going bore 30 to engage with the second receiving part 48. By e.g. relative rotation the first nut 26 and the first screw 22 are assembled into a tight engagement.

Fig. 2c shows the distal end 42 of the first screw 22 inserted through the frame 6, the first nut 26 inserted into the inner opening 27 of the bearing 28, and the first outer engagement element 44 in engagement with the first inner engagement element 38, where the first through-going bore 30 and the second through-going bore 40 are substantially coaxial creating axial access through the first screw 22 and the first nut 26.

The first nut 26 can have a flange 50 extending outward in the radial direction of the first through-going bore 30, so that the first nut holds the bearing 28 in place.

Fig. 2d shows a bayonet mount 52 with an inner bayonet mount 54 and an outer bayonet mount 56. Fig. 3a shows a standard wheel 8 used for an inline skate, a roller ski, a kick scooter, or a skateboard having a non-inflatable tyre 104 made of hard rubber or plastic, preferably polyurethane surrounding a rim 106 made of plastic or metal. The rim has a standard opening 108 forming a cylindrical cavity for receiving two bearings (not shown) one at each end of the standard opening with the bearings contacting sides of a fixed spacer 109 with a smaller diameter than the rest of the standard opening in between to keep the bearings in place at the edges of the cylindrical cavity. A bolt and nut (not shown) through the two bearings and the spacer hold the wheel to the frame 6 in such a way that the wheel can rotate.

Fig. 3b shows the wheel 8 of Fig. 3a, where two wheel rim parts 106a,b (only one is shown) are positioned in the standard opening 108 and fastened to each other and/or to the rim 106. The two wheel rim parts have a first holding mechanism 102 at the centre of the wheel.

The first holding mechanism can have any design that prevents relative rotation between the first holding mechanism 102 and the corresponding suitable key, when the key and the first holding mechanism are in engagement with each other. The first holding mechanism can have a design to receive a torx key, a phillips key, pozidriv key, a slot key.

Fig. 3c shows a cross-section of the wheel 8 through the centre of the wheel with the two wheel rim parts 106a,b positioned in the standard opening 108 with the fixed spacer 109 with a smaller diameter than the rest of the standard opening. Each wheel rim part comprises the first holding mechanism 102.

Fig. 3d shows one of the two wheel rim parts 106a,b. The wheel rim parts 106a,b can have one or more knives 1 10 with sharp edges 1 10a on the side of the wheel rim part configured to face the wheel so that the one or more knives is/are cut into or squeezes the rim 106 of the wheel when the two wheel rim parts are connected to each other. With the two wheel rim parts 106a, b squeezed into the rim 106, the two wheel rim parts and the wheel cannot rotate relative to each other. The one or more knives extend(s) radially so that the one or more knives is/are not bent when squeezed into the rim. The one or more edges of the knives can form angles, which is neither parallel nor perpendicular to the wall of the cylindrical cavity of the standard opening so that the knives cut further into the rim 106 the more the two wheel rim parts 106a,b are pressed together.

Fig. 3e shows the wheel rim part 106a in a perspective view to show an indentation 1 14 with a bottom 1 16 and a sidewall 1 18. A bearing (not shown) can be positioned in the indentation, where an outer ring of the bearing is preferably fastened or fixated to the sidewall.

Fig. 3f shows the wheel rim part 106a from the left in Fig. 3d. The first holding mechanism 102 is shown as well as a first hole 120a and a second hole 120b through the bottom 1 16 of the indentation 1 14. When the two wheel rim parts 106a,b are pressed into the standard opening 108 in the rim 106, the two wheel rim parts 106a,b are fastened to each other by two second screws (not shown) one in each hole 120a, b. The first hole 120a has a first indentation 122 for receiving the head of the second screw so that the head of the second screw preferably flushes with the bottom 1 16 of the indentation 1 14 or at least does not stick out above the surface of the bottom 1 16. The second hole 120b is threaded so that the second screw inserted through the first hole 120a of the other wheel rim part (not shown) engage with the thread of the second hole 120b. Likewise, the second screw inserted into the first hole 120a of the shown wheel rim part 106a will engage with the thread of the second hole of the other wheel rim part. This way the two wheel rim parts can be made identical lowering the manufacturing costs.

Alternatively, one of the two wheel rim parts has a female part and the other wheel rim part has a corresponding male part (not shown) that can engage with the female part (not shown) when the two wheel rim parts are pressed together. It is also possible within the invention that each wheel rim part has a female part and a male part that can engage with the male part and the female part of the other wheel rim part. Again the two wheel rim parts can be made identical.

Preferably, the two wheel rim parts 106a, b are made of metal to increase strength and stability. If the two wheel rim parts 106a, b are made of a light-alloy the two wheel rim parts 106a,b will also be very light. Fig. 3g shows another embodiment of a wheel 8’, where a rim 106’ has in the standard opening 108 a plate 123 in the middle of the standard opening 108, where the plate has the first holding mechanism 102 formed in the centre of the plate and of the wheel. The plate is integral with the rim. To increase the strength of the rim comprising the plate, the rim is made of metal preferably a light alloy. The plate 123 is formed so that the standard opening 108 can receive bearings, one bearing on each side of the plate, where the bearings are pressed against and engage with the cylindrical wall of the cylindrical cavity of the standard opening 108.

Fig. 3h shows a piece 124, preferably a metal piece, having teeth 126 and the first holding mechanism 102 in the centre. In this embodiment the first holding mechanism 102 has the form suitable for receiving a torx key, but the form can be any form that prevents rotation between the first holding mechanism and the corresponding key. This piece can be moulded in the middle of the standard opening 108 of the wheel 8 shown in Fig. 3a. The teeth 126 will increase the attaching strength between the piece 124 and the cylindrical wall of the cylindrical cavity of the standard opening 108. On each side of the piece 124 the standard opening is able to receive bearings, where the bearings are pressed against and engage with the cylindrical wall of the cylindrical cavity of the standard opening 108.

In all of the embodiments, the first holding mechanism 102 has a certain length, like more than 2 mm, preferably more than 3 mm, even more preferably more than 4 mm, so that the momentum from a driving shaft (not shown) acting on the first holding mechanism 102 is transferred to a larger area resulting in less wear on the first holding mechanism 102 and on the driving shaft.

Fig. 4a shows a cross-section of the wheel 8,8’ mounted to the frame 6 by two sets of the first screw 22, the bearing 28, and the first nut 26, one set on each side of the wheel. In principle, only one set would be necessary on the side of the wheel where the engine is to be positioned. Flowever, if the wheel is supposed to have support on both sides, it will be advantageous to have two sets, since the first tool can be preferably used to engage with the second receiving part 48 when the first screw and the first nut are engaged with each other. A driving shaft 202 driven by the engine unit 10 and having a second holding mechanism 204 that is engageable with the first holding mechanism 102 at the centre of the wheel can now been introduced through the second through-going bore 40 and the first through-going bore 30. In the shown example, the second holding mechanism is a torx key and the first holding mechanism is an opening for the torx key. However, the first and second holding mechanisms can be a hex key, a phillips key, pozidriv key, a slot screwdriver, or any key that can transfer a rotational movement. The only condition is that the first and second holding mechanisms engage with each other and that a rotational movement can be transferred from the driving shaft to the wheel. When the second holding mechanism 204 engages with the first holding mechanism 102, the engine unit 10 can be fastened, e.g. by ordinary screws (not shown), to the frame 6.

Fig. 4b shows the wheel 8,8’ mounted to a fraction of a frame 6’ of a roller ski a kick scooter, or a skateboard, where only a fraction of the frame is shown. The wheel is mounted to the frame by at least one set of the first screw (not shown), the bearing (not shown), and the first nut (not shown). The engine unit 10 drives the wheel using a driving shaft (not shown) in the same way as shown in Fig. 4b. The engine unit 10 is attached to the frame 6’ by a bolt 210. Instead of or in addition to the engine unit, a brake can be connected to the frame 6’ and to the wheel in the same way.

Fig. 5a shows a brake 302 comprising a brake drum 304. The brake comprises fastening means (not shown) to connect the brake to the frame. A set of shoes or pads (not shown) positioned on the inside of the drum, can be pressed radially outward on the inner surface of the drum when the brake is activated. The brake comprises a torque arm 306 with a torque arm opening 308 for fixating the torque arm to the frame. Preferably, an ordinary screw (not shown) can be inserted through the torque arm opening 308 and fastened to e.g. a thread in the second through-going bore 40 of the first screw 22 of another wheel, or the fastened to the frame.

The brake also comprises a brake shaft 310 having the second holding mechanism 204, where the second holding mechanism 204 can engage with the first holding mechanism 102 at the centre of the wheel when the brake is mounted to the frame.

The brake is activated mechanically or electrically by a handle (not shown) held by the user through a wire (not shown) between the handle and the brake 302. If the brake is activated electrically, the signal from the handle to the brake can be transferred wirelessly. If the brake is activated electrically, the battery 12 can supply the necessary energy so that the brake actually is activated.

Fig. 5b shows the brake 302 mounted to the frame 6 of an inline skate 2. The brake can be mounted on one side of the wheel and the engine unit can be mounted on the other side of the same wheel. The brake can be acting on any of the wheels 8,8’. With the brake acting on one of the middle wheels or on the rear wheel the risk that the user falls flat on his or her face is reduced. With the brake acting on the front wheel a higher braking force can be applied without the wheel on which the brake acts is locked and without the wheel sliding unrotationally.

Especially on a roller ski a kick scooter, or a skateboard the brake can preferably be acting on the front wheel, since the risk of falling flat on the face is lower due to the longer distance between the front wheels and the point of gravity of the user compared to when using the inline skate. The brake will brake more efficiently when acting on the front wheel.

Preferably, two brakes (not shown) connected to each other by the torque arm can be acting on two wheels of the same inline skate for increasing the braking ability.

Fig. 6 shows the engine unit 10 with a top cover removed exposing a transmission 402 positioned in a bottom cover 404 and an engine (not shown), where the transmission transfers the rotational movement of the engine to the driving shafts (not shown).

The engine is acting directly on a first cogwheel 406 by rotation. The first cogwheel 406 acts directly on a first driving shaft cogwheel 408, on which one of the driving shafts is rotatingly connected. The first driving shaft cogwheel 408 acts through intermediate cogwheels 408,409,410 also on a second driving shaft cogwheel 412, on which the other of the driving shafts is rotatingly connected. The first 408 and second 412 driving shaft cogwheels have the same number of teeth and will rotate with the same rotational speed and will preferably act on wheels with the same diameter to avoid unnecessary wear on the wheels.

The bottom cover 404 comprises a first bottom cover 414 and a second bottom cover 416, where the first and the second bottom covers are pivotable in relation to each other around the rotation axis of the first cogwheel 406. The same is true for the top cover (not shown). This allows the first 408 and the second 412 driving shaft cogwheels and thus the two driving shafts to move away from or closer to each other, and the distance between the two driving shafts can be adjusted to fit the distance between the two wheels, which the driving shafts are supposed to drive.

Fig. 7a shows an embodiment of a second nut 26’, where the second nut 26’ can have all the features of the first embodiment of the first nut 26 except that the second nut 26’ does not have the second receiving part 48 and that the first inner diameter with the first inner engagement element 38 can be through all of the first through-going bore 30.

The second nut 26’ can have two protrusions 502a, b or third holding mechanisms at a proximal end 504 of the second nut.

Fig. 7b shows the second nut 26’ when seen from the left in in Fig. 7a. The two protrusions 502a, b are positioned on each side of the first through-going bore 30, where first sides 506a, b of the protrusion 502a are substantially parallel with each other and, where second sides 508a, b of the protrusion 502b are substantially parallel with each other and extend in the direction of the first sides 506a, b.

Normally the frame will have two frame parts one on each side of the wheel so that the wheel can have support on both sides of the wheel. This is not necessarily true for e.g. skateboards and ick scooters. Fig. 7c shows a fragment of a modified frame 6” for an inline skate, a roller ski, a kick scooter, or a skateboard seen from where the wheel will normally be positioned between the two frame parts.

The modified frame 6” has all features of the frame 6 described above including the first opening 24. The modified frame 6” differs from the frame 6,6’ in having two slots 510a,b or fourth holding mechanisms one on each side of the first opening. The slots 510a,b are configured to tightly receive the protrusions 502a, b of the second nut 26’ so that the second nut cannot rotate when the protrusions 502a, b and the slots 510a,b engage with each other. In this way, the second nut is prevented from rotating relative the frame when the first outer engagement element 44 of the first screw 22 shown in Fig. 2a engages with the first inner engagement element 38 of the second nut. Other embodiments of the third and fourth holding mechanisms are also possible within the invention, like round or square dots on one side and indentations of the same size and shape on the other side.

Items

The presently disclosed invention may be described in further detail with reference to the following items.

1. A fixation device for fixating a wheel with a bearing to a frame of an inline skate, a roller ski, a kick scooter, or a skateboard comprising a first nut having a first through-going bore along a first axis comprising a proximal part with a first inner diameter and a distal part with a second inner diameter, wherein

the second inner diameter is smaller than the first inner diameter, the proximal part has a first inner engagement element configured to prevent displacement along the first axis, and

the distal part has a receiving part, where the receiving part is configured to receive a first tool inserted through the proximal part of the first through- going bore, so that the first nut and the first tool cannot rotate in relation to each other when the receiving part has received the first tool.

2. The fixation device according to item 1 , wherein

the first nut has a flange extending outward in the radial direction of the first through-going bore, preferably the flange is positioned at the distal part of the first nut, more preferably the flange flushes with a distal end of the first nut at the distal part of the first nut,

the outside of the first nut is tapered or conical, or

the outside of the first nut has a second outer engagement element.

3. The fixation device according to any of the item 1 -2, wherein the fixation device comprises a bearing with an inner opening, where

the first nut having a flange is positioned in the inner opening, the inner opening is tapered or conical, and the tapered or conical first nut is positioned in the tapered or conical inner opening,

the inner opening has a second inner engagement element correspondingly fitting the second outer engagement element of the first nut, and the second inner engagement element and the second outer engagement element are in engagement with each other,

the first nut is press-fit into the bearing, the first nut is positioned into the inner opening of the bearing and the first nut and bearing is glued together, and/or

the inner opening of the bearing is the first through-going bore of the first nut. The fixation device according to any of the preceding items, wherein the fixation device comprises a first screw with an first outer engagement element correspondingly fitting the first inner engagement element of the first nut, where the first screw has a second through-going bore configured to allow access for the first tool to engage with the receiving part when the first inner engagement element and the first outer engagement element are in engagement with each other. The fixation device according to item 4, configured such that when the first nut is positioned in the bearing, and the bearing is positioned in an indentation in the side of a wheel having a first holding mechanism at the centre of the wheel, and the first nut and the first screw are in engagement with each other through a first opening of a frame of an inline skate, a roller ski, a kick scooter, or a skateboard thereby fixating the wheel with the bearing to the frame, the first through-going bore and the second through-going bore provide direct access to the first holding mechanism of the wheel. A wheel kit comprising

a wheel for inline skates, roller skis, and/or kick scooters, and two wheel rim parts configured to be positioned on each side of the wheel and to engage with the wheel when the two wheel rim parts are connected to each other or to each side of the wheel,

a wheel for inline skates, roller skis, and/or kick scooters, having a centre piece moulded in the centre of the wheel, or

a wheel for inline skates, roller skis, and/or kick scooters comprising a rim totally, or at least substantially, made of metal,

where at least one, preferably both, of the wheel rim parts, the centre piece, or the rim comprises a first holding mechanism engageable with a second holding mechanism of a driving shaft or a braking shaft. The wheel kit according to item 6, wherein at least one, preferably both, of the two wheel rim parts has one or more edges or knives on the side of the wheel rim part configured to face the wheel so that the one or more edges is/are cut into or squeezes the wheel when the two wheel rim parts are connected to each other. The wheel kit according to item 7, wherein the one or more edges extends substantially radially. The wheel kit according to any of the items 6-8, wherein at least one, preferably both, of the wheel rim parts have an indentation configured for receiving a first nut according to items 1 -3 positioned within a bearing. The wheel kit according to any of the items 6-9, wherein at least one, preferably both, of the two wheel rim parts or the centre piece is made of metal. A device comprising

the fixation device according to any of the preceding items,

a wheel having a first holding mechanism at the centre of the wheel, and a shaft having at a distal end a second holding mechanism that is engageable with the first holding mechanism,

wherein the first through-going bore and the second through-going bore are configured so that the first holding mechanism of the wheel is reachable by the second holding mechanism of the shaft through the first through-going bore and the second through-going bore. The device according to item 1 1 , wherein the wheel comprises two wheel rim parts one on each side of the wheel, wherein

at least one of the wheel rim parts comprises the first holding mechanism, and

the two wheel rim parts are connected to each other, e.g. by ordinary screws, to keep the wheel in between. The device according to item 12, wherein at least one of the two wheel rim parts has one or more edges on the side of the wheel rim part facing the wheel so that the one or more edges is/are cut into or squeezes the wheel when the two wheel rim parts are connected to each other. The device according to items 12 or 13, wherein the two wheel rim parts are made of metal. The device according to item 1 1 , wherein a metal piece comprising the first holding mechanism is moulded into the centre of the wheel. The device according to any of the items 1 1 to 15, wherein the device comprises a bearing with an inner opening, wherein the first nut of the fixation device is placed in the inner opening of the bearing, and wherein the bearing is positioned in an indentation in one side of the wheel and/or in one of the two wheel rim parts. The device according to item 16, wherein the first screw positioned in a first opening of a frame of an inline skate, a roller ski, a kick scooter, or a skateboard is engaged with the first nut placed in the inner opening of the bearing. The device according to any of the items 1 1 to 17, wherein the device is a driving device and the shaft is a driving shaft, and the driving device comprises

an engine connected to a proximal end of the driving shaft for driving the driving shaft. The device according to any of the items 1 1 to 18, wherein the device is a braking device and the shaft is a braking shaft, and the braking device comprises a brake connected to a proximal end of the braking shaft for braking the driving shaft. The braking device according to item 19, wherein the brake is a drum brake, a disc brake, a magnetic brake, an induction brake, or a band brake. A first engine kit for an inline skate, a roller ski, a kick scooter, and/or a skateboard, comprising:

a driving shaft, an engine configured to be mounted to a frame of an inline skate, a roller ski, a kick scooter, or a skateboard, comprising a driving element configured for driving the driving shaft, and

a fixation device according to any of the preceding items. The first engine kit according to item 21 , wherein the engine comprises a transmission element so that the engine with the transmission elements has two driving elements so that the engine is configured to drive two parallel driving shafts, where the distance between the two driving elements corresponds to the distance between two wheels of an inline skate. The first engine kit according to item 22, wherein transmission element comprises two transmission element parts pivotable to each other around an axis parallel with the rotation axis of the driving elements. A method of installing an engine and/or a brake on an inline skate, a roller ski, a kick scooter, or a skateboard having a frame with a first opening holding a first wheel, the method comprising the steps of

removing a first wheel from the frame,

positioning a first nut according to any of the items 1 to 17 in an inner opening of a bearing,

positioning the bearing in a first indentation of a second wheel having a first holding mechanism at the centre of the wheel, or removing one or two bearings from a standard opening of the first wheel, connecting two wheel rim parts to each other on each side of the first wheel in the standard opening, where at least one of the two wheel rim parts has a first holding mechanism at the centre of the wheel rim part, and positioning the bearing in a second indentation of the first wheel and/or of at least one of the wheel rim parts,

engaging the first nut with a first screw according to items 4 or 5 with the first opening of the frame between the first nut and the first screw, and positioning a driving shaft or a braking shaft having at a distal end a second holding mechanism that is engageable with the first holding mechanism through the second through-going bore of the first screw and the first through-going bore of the first nut to engage with the first holding mechanism, the driving shaft is driven by the engine or the braking shaft is braked by the brake. The method according to item 24, wherein during engaging the first nut with the first screw, a first tool is inserted through the second through-going bore of the first screw and the proximal part of the first through-going bore of the first nut to engage with the receiving part, and a second tool is engaged with the first screw preventing relative rotation, and rotating the first tool and the second tool in relation to each other. A second engine kit for an inline skate, a roller ski, a kick scooter, or a skateboard having a frame, the engine kit comprising:

an engine configured to be mounted to a frame of an inline skate, a roller ski, a kick scooter, or a skateboard, comprising a driving element configured for driving a driving shaft,

a wheel for inline skates, roller skis, and/or kick scooters, having a first holding mechanism at the centre of the wheel,

a driving shaft having a proximal end configured to be driven by the engine and a distal end having a second holding mechanism engageable with the first holding mechanism,

a second fixation device, comprising:

a second nut having a first through-going bore with a first inner engagement element,

a first screw according to any of the items 1 to 17 with an first outer engagement element correspondingly fitting the first inner engagement element of the second nut, where the first screw has a second through- going bore,

where the first through-going bore and the second through-going bore are configured to rotatingly receive the driving shaft,

a drill bit for drilling a hole using a drill through the frame of the inline skate, the roller ski, or the kick scooter, and through the second nut, and a pin for being inserted in the hole drilled by the drill bit to prevent the second nut from rotating relative the frame. The second engine kit according to item 26, further comprising: a bearing with an inner opening for receiving the second nut, wherein the wheel is configured to receive the bearing. The second engine kit according to any of the items 26 to 27, further comprising: a frame for an inline skate, a roller ski, a kick scooter, or a skateboard, wherein the second nut and/or the bearing has a third holding mechanism, and the frame has a fourth holding mechanism, wherein the third holding

mechanism and the fourth holding mechanism are engagable with each other to prevent rotation of the second nut relative the frame when the second nut and/or the bearing is assembled with the frame. The second engine kit according to any of the items 26-28, further comprising: a pair of wheel rim parts according to any of the items 6-28. A pair of wheel rim parts according to any of the items 6-29. A braking kit according to any of the items 21 -23, or 26-29, where the engine of the first engine kit or the second engine kit for driving a driving shaft is replaced with a brake for braking a braking shaft with a distal end having the second holding mechanism. An inline skate, a roller ski, a kick scooter or a skateboard comprising a frame with a first opening, wherein the first engine kit according to any of the items 21 to 23 or the second engine kit according to any of the items 26 to 29 and/or the braking kit according to item 31 is/are assembled, wherein the assembled first engine kit or the second engine kit is mounted to the frame for driving the wheel through a driving shaft according to item 18 or the assembled braking kit is mounted to the frame for braking the wheel through a braking shaft according to item 19. The inline skate according to item 32, wherein two braking kits are assembled and, wherein the two assembled braking kits are mounted to the frame for braking two wheels independently. A method of installing an engine and/or a brake on an inline skate, a roller ski, a kick scooter, or a skateboard having a frame with a first opening holding a first wheel, the method comprising the steps of

removing a first wheel from the frame,

positioning a third nut in an inner opening of a bearing, where the third nut has a first through-going bore with an first inner engagement element, positioning the bearing in a first indentation of a second wheel having a first holding mechanism at the centre of the wheel, or removing one or two bearings from a standard opening of the first wheel, connecting two wheel rim parts to each other on each side of the first wheel in the standard opening, where at least one of the two wheel rim parts has a first holding mechanism at the centre of the wheel rim part, and positioning the bearing in a second indentation of the first wheel and/or of at least one of the wheel rim parts,

positioning the first wheel or the second wheel with the bearing and the third nut at the frame,

drilling holes through the frame and through the third nut and/or an inner ring of the bearing,

positioning rods in the drilled holes, where the rods has substantially the diameter of the drilled holes, preventing rotation of the third nut and the inner ring of the bearing relative the frame,

engaging the third nut with a first screw according to item 4 or 5 with the first opening of the frame between the first nut and the first screw, and positioning a driving shaft or a braking shaft having at a distal end a second holding mechanism that is engageable with the first holding mechanism through the second through-going bore of the first screw and the first through-going bore of the first nut to engage with the first holding mechanism, the driving shaft is driven by the engine or the braking shaft is braked by the brake.