WO2008067822A2

WO2008067822A2 - A motorised multi-purpose driving wheel

Info

Publication number: WO2008067822A2
Application number: PCT/DK2007/000537
Authority: WO
Inventors: George Manus
Original assignee: Nordict A/S
Priority date: 2006-12-07
Filing date: 2007-12-07
Publication date: 2008-06-12
Also published as: WO2008067822A3

Abstract

The invention provides a motorised driving wheel (1) comprising a circumferential rim (2) defining an axis of revolution and a motor (3) for producing a driving force. The motor comprises an output shaft rotatable around a motor axis, the motor axis and the axis of revolution being non-parallel. Furthermore, the driving wheel comprises a transmission system for transmitting the driving force from the motor to the circumferential rim. The transmission system is arranged to transform rotation of the output shaft around the motor axis into rotation of the circumferential rim around the axis of revolution. The transmission system may drive an annular element (5) forming the rim, or it may drive a central driving axle (114).

Description

A MOTORISED MULTI-PURPOSE DRIVING WHEEL

Technical field

The present invention relates to a motorised multi-purpose driving wheel. The wheel is suitable for mounting to a wide variety of mobile appliances, such as various carts, golf trolleys, bicycles, wheelchairs, small vehicles, wheelbarrows etc.

Background of the invention

Various wheels and driving systems therefore have been proposed in the prior art. One such wheel and driving system is disclosed in EP-A-I 350 652, which discloses a motorised driving wheel comprising a circumferential rim defining an axis of revolution. The wheel system further comprises an electrical motor for producing a driving force, the motor comprising an output shaft rotatable around a motor axis. A transmission system is provided for transmitting the driving force from the motor to the circumferential rim. More specifically, the output shaft of the motor is provided with a gearwheel engaging a toothed inner circumferential portion of the wheel, so as to apply the driving force of the motor to the rim for advancing the wheel, the motor axis being substantially parallel to the axis of revolution of the rim. The wheel forms a housing enclosing the motor and a plurality of batteries, which provide electrical power to the motor.

It has been found that such a wheel system suffers from the drawback that the longitudinal dimension of the motor is limited by the width of the wheel, thereby putting an upper limit to the power producable by the motor.

Summary of the invention

It is therefore an object of preferred embodiments of the present invention to provide a driving wheel, in which the longitudinal dimension of the wheel is not limited by the width of the wheel, to allow a more powerful motor to be arranged within the physical borders of the wheel.

In a first aspect, the present invention hence provides a motorised driving wheel comprising: - a circumferential rim defining an axis of revolution;

- a motor for producing a driving force, the motor comprising an output shaft rotatable around a motor axis;

- a transmission system for transmitting the driving force from the motor to the circumferential rim; wherein the axis of revolution and the motor axis are non-parallel, and wherein the transmission system is arranged to transform rotation of said output shaft around the motor axis into rotation of the circumferential rim around the axis of revolution.

Due to the fact that the motor axis and hence the motor itself extends non- parallel to the axis of revolution of the rim, the longitudinal extent of the motor is not limited by the width of the wheel or the width of the rim. In embodiments of the invention, in which the motor is entirely housed in the wheel, the longitudinal extent of the motor is merely limited by a diagonal or radial dimension of the wheel, which, in most instances, is significantly larger than the width of the wheel. The motor is preferably an electrically driven motor.

The axis of revolution of the rim may extend transversely to the motor axis. In one embodiment, the axis of revolution of the rim is substantially orthogonal to the motor axis, which may especially be an advantage in order to house the motor entirely within the rim.

The motor may comprise a power connection element for receiving an electrical driving power from an external power source. The power source may be positioned on an appliance incorporating the driving wheel and may be connected to the motor via the power connection element and a wire. It is thus possible to avoid batteries occupying space within the driving wheel, thereby facilitating use of a larger motor. The circumferential rim may form an outer surface of an annular element, of which the inner circumferential surface may be toothed. In order to transform rotation of the output shaft of the motor into rotation of the circumferential rim, the transmission system may comprise a first gearwheel for engaging the toothed inner surface of the annular element. In an alternative embodiment, the inner circumferential surface may not be tooted, and the first gearwheel may be replaced by one or more wheels biased in engagement with the inner surface of the annular element to transmit a driving force via a frictional interengagment. For example, the one or more wheels may have an outer surface portion made from rubber. In a further alternative embodiment, rubber wheels and a first gearwheel may be applied in combination. As an alternative to rubber wheels, wheels of another material may be chosen, i.e. a material allowing for sufficient friction in order to ensure transmission of the driving force.

The first gearwheel may have an axis of rotation, which is substantially parallel to the axis of revolution of the circumferential rim, i.e. the first gearwheel may be situated in the same plane as the circumferential rim, e.g. in a space within the wheel, or alternatively in a plane substantially parallel to the circumferential rim.

The first gearwheel may be mounted around a first gear axis. The transmission system may further comprise a second gearwheel, which may be conical, and which may also be mounted around the first gear axis. This second gearwheel may be arranged for interengagement with a third gearwheel, which may be conical, and which may be mounted around a further gear axis, which is non- parallel to the first gear axis. Having conical second and third gearwheels allows for the interengagement of the second and third gearwheels even though the axes around which they rotate are non-parallel.

In some embodiments an additional number of gears may be applied allowing for different gear of the wheel dependent on the speed of an appliance incorporating the motorised driving wheel. The further gear axis, around which the third gearwheel is mounted, may by substantially parallel to the motor axis. In one embodiment, the motor axis and the further gear axis may by substantially identical allowing for the third gearwheel and the motor to be positioned end to end on one axel.

In one embodiment, only one gear wheel may be applied for transmitting the motor drive force to the circumferential rim. As an example, the output shaft may be a worm shaft engaging said gear wheel. The gear wheel may be mounted on a shaft being positioned at the axis of revolution of the circumferential rim, thus allowing a wheel member forming said circumferential rim to rotate around the same axis as the gear wheel.

The transmission system may comprise a coupling device in order to be able to transfer the motor drive force to the circumferential rim. The coupling device may ensure that the wheel member rotates together with the gear wheel.

The gear wheels may be made from a synthetic material e.g. plastic, from metal or from any other suitable material, In some embodiments, the weight of the driving wheel and thus the gear wheels are highly important, hence gear wheels of plastic or aluminium may be preferred. The number of teeth and the angle of the conical gears are design parameters which may also be chosen in dependency of the mobile appliance on which the motorised driving wheel is to be mounted. The circumferential rim may likewise be made from a synthetic material e.g. plastic, from metal or from another suitable material.

The aforementioned driving wheels and the inner circumferential rim may providing a gearing of the driving force. In embodiments, in which the driving force is transmitted via frictional interengagement between the parts, the gearing may be infinitely variable, whereas in the case of toothed gearwheels, the gearing may be constant. Alternatively, a gear shifting mechanism may be provided for shifting gears.

From the above description it will be appreciated that the circumferential rim may be formed by an annular element, which has a toothed inner driving surface. Alternatively, the circumferential rim may be formed on a circular wheel element supported and driving by a central driving axle, which in turn is driven by the motor. In such an embodiment, the motor output shaft may drive a fourth gearwheel mounted to an intermediate driving shaft, the intermediate driving shaft supporting a fifth gearwheel, which engages a sixth gearwheel mounted to and driving the central driving shaft.

The circumferential rim may span a cylinder, in which cylinder the motor is entirely contained, i.e. the motor does not extend beyond the borders of the geometrical cylinder spanned by the rim. By avoiding elements projecting out from the wheel, the motor is protected during rotation of the wheel. In order to increase safety even further, the cylinder may be closed at both ends.

Dependent on the mobile appliance on which the motorised driving wheel is to be mounted, the driving wheel may further comprise a tyre being mounted around the outer surface of the circumferential rim. This may e.g. be case when mounted on mobile appliances carrying items being sensitive to bumps, e.g. wheelchairs and baby carriages, or for comfort reasons, e.g. when mounted e.g. on a bike and a wheelbarrow.

In order to position the motor in relation to the driving wheel, the driving wheel may further comprise a suspension element for supporting the motor.

The suspension element may further support a plurality of stabilising wheels rotatably mounted with respect to the suspension element, whereby respective outer circumferential surfaces of the stabilising wheels may be in contact with the inner circumferential surface of the circumferential rim. The stabilising wheels may comprise a groove along their outer circumferential surface, the respective grooves forming stabilizing paths for the teeth of the inner surface of the circumferential rim, so as to stabilise the suspension element within the wheel. This may further facilitate rotation of the wheel without rotation of the suspension element. The suspension element may be non-rotatably mounted to a supporting shaft. The supporting shaft may be central with respect to the circumferential rim, but other configurations are possible, in which the supporting shaft is offset from the axis of revolution of the rim.

In certain embodiments of the invention, in particular such embodiment, in which one or more wheel members mounted to and driven by a central driving shaft, the suspension element may be securable to an external appliance.

The transmission system may comprise a coupling device for selectively coupling and decoupling the motor drive force to the rim. Thereby, idling of the wheel is facilitated, in order to reduce the level of manual power required for manual movement of an appliance incorporating the wheel. The coupling device may comprise at least one clutch achieving the coupling and decoupling. The clutch may infinitely vary the amount of driving force transmitted from the motor to the circumferential rim.

In one embodiment, decoupling may be achieved e.g. by disengaging one gear wheel and the output shaft of the motor. Alternatively, two gear wheels may be brought out of engagement with each other.

In another embodiment, decoupling may be achieved by disengaging the at least one clutch and a wheel member forming the circumferential rim portion. This may be done automatically dependent on the rotational speed of the output shaft or may be done manually by a switch. Switching off the motor may in some embodiments automatically ensure that the at least one clutch is disengaged from the wheel member.

The at least one clutch may thus be arranged to provide motor drive force transmission to the rim only when the rim is not rotating at a higher speed than a driving speed set by the rotational speed of the output shaft. And the clutch may further be arranged to release the rim from motor drive force engagement when the rim is rotating at a higher speed than said set driving speed. As an example, the driving wheel may comprise at least one clutch which incorporates one or more rollers, e.g. 3-8 rollers or even more, which may be arranged in a substantial circular indention in the wheel member. To be able to retain the rollers in the indention a fixation member may be used. The fixation member may comprise a notch for each of the rollers. Furthermore, the fixation member may form part of or may be attached to a gear wheel which may form part of the transmission system and which may thus transmit the driving force from the motor to the circumferential rim.

The notches may be larger at one end than at the other end. They may e.g. be formed substantially as a triangle or have another form with a decrease size at one end.

When rotating the gear wheel, the rollers may move within the notches form from the one end with a larger size to the end with a smaller size. Due to the size of the notch at this position, they may thus press towards an inner surface of the indentation, the inner surface defining the circumference of the indentation. When being pressed towards the inner surface, the rollers may be secured between the inner surface and the fixation member, and the gear wheel may thus turn the wheel member and thereby rotate the circumferential rim.

If the speed of the wheel member exceeds the speed of the gear wheel, the rollers may return to their initial positions in the notches where they are not pressed towards the wheel member allowing for freewheeling of the wheel member, and thus release the rim from motor drive force engagement.

As the speed of the wheel member decreases, the rollers may again move within the notches and they may again be pressed towards the inner surface of the wheel member allowing for motor drive force transmission to the rim.

The driving wheel may further comprise a locking member adapted to lock at least a part of a wheel member forming the circumferential rim to the transmission system. As an example, the wheel member may be locked to a gear wheel, e.g. by the use of at least one locking pin which may extend through both the gear wheel and the wheel member, thereby locking them together to assure that they move together. If the locking member is activated, freewheeling of the wheel is not possible.

As the speed of a mobile appliance on which the driving wheel can be mounted may be too high, the driving wheel may further comprise a braking system activateable to decrease the speed of rotation of the circumferential rim.

The braking system may e.g. be manually activateable so that a person in control of the mobile appliance has to decide whether to activate the braking system or not. Alternatively or additionally, the braking system may comprise an automatic control which may ensure a decreased speed of rotation of the circumferential rim at a given set point for the speed.

The set point may in some embodiments be variable, so that the person in control may change the set point e.g. dependent on the structure of the ground on which the driving wheel runs, dependent on the weather conditions, or dependent on the load being carried by the mobile appliance, etc.

As the rotational speed of the driving wheel in some embodiments may be changeable by manually changing the output of the motor, the braking system may be provided so that the braking system is activateable to decrease the speed of rotation of the circumferential rim only when the motor drive force is decoupled from the rim, i.e. during freewheeling of the wheel.

The speed may be decreased by applying frictional forces directly on the wheel member forming the circumferential rim portion. Thus, the braking system may e.g. comprise a gripping device which may be adapted to grip around at least a part of the wheel member to decrease the speed of rotation of the rim. The wheel member may form the circumferential rim.

In one embodiment, the gripping device may comprise two gripping arms acting as a jaw which may e.g. grip around a protruding part of the wheel member, when activated. The gripping arms may be positioned so that they permanently at least partly encircle at least a part of the wheel member and by activation of the arms, they may be moved to a gripping position in which they grip at least a part of the wheel member, e.g. by tilting them around their attachment axis. A spring mechanism may facilitate that they are tilted back to their initial position when not activated.

When mounted on some specific mobile appliances it may be an advantage if the driving wheel can rotate in both a forward and a reverse direction. Thus, at least one of the motor and the transmission system may be arranged to drive the rim in a first, forward direction and in a second, reverse direction.

Reverse rotation may be provided by changing the direction of rotation of the output shaft.

If an embodiment incorporates the above-described coupling device for coupling and decoupling the motor drive force to the circumferential rim, the transmission system may not necessarily be able to drive the rim in reverse direction. This may be solved by applying a locking member which may be able to lock a part of the transmission system to the wheel member.

In some applications, it may be an advantage if the driving wheel comprises a shock absorbing system being capable to dampen influences on the wheel during rotation of the circumferential rim, e.g. when striking a stone. The driving wheel may therefore further comprise an elasticity element being adapted to elastically suspend the motor. The elastically member may in one embodiment comprise one or more springs.

In order to facilitate turning of a mobile appliance incorporating a driving wheel according to the invention, the driving wheel may comprise a steering element being adapted to change the angle between the axis of revolution of the circumferential rim and a suspension structure for the wheel.

In one embodiment, the wheel member forming the circumferential rim and the motor may be connected so that turning of the wheel also turns the motor. In such an embodiment, the suspension structure for the wheel may be connected to the mobile appliance and the driving wheel may thus be turned relative hereto in order to turn the mobile appliance to the right or to the left.

In an alternative embodiment, the steering element may be able to change the angle between the axis of revolution and the motor axis, e.g. if the motor is pivotable suspended in the driving wheel so that is turns together with the mobile appliance.

In a second aspect, the present invention provides a mobile appliance comprising at least one motorised driving wheel comprising a circumferential rim defining an axis of revolution, a motor for producing a driving force, the motor comprising an output shaft rotatable around a motor axis, a transmission system for transmitting the driving force from the motor to the circumferential rim, wherein the axis of revolution and the motor axis are non-parallel, and wherein the transmission system is arranged to transform rotation of said output shaft around the motor axis into rotation of the circumferential rim around the axis of revolution.

It should be understood, that the above mentioned features of the first aspect of the invention may also be applicable to the at least one motorised driving wheel of the mobile appliance of the second aspect of the invention.

The mobile appliance may e.g. include a golf trolley, a bicycle, a wheelchair, a baby carriage, a stroller, a shopping trolley, a mobile shopping basket, a wheelbarrow, a vehicle, a golf cart, a golf trolley, a toy cart and various other carts, a machine cart, such as an agricultural cart, a mower, such as a lawnmower, a truck, a fork-lift truck, etc. One example of a golf trolley suitable for the wheel of the present invention is the trolley disclosed in WO

2005/087568, which is hereby incorporated by reference. One or both of the wheels of the trolley of WO 2005/087568 may be exchanged by a wheel of the present invention. The mobile appliance may comprise an electrical power source for the motor, which power source may be arranged externally with respect to the at least one wheel. A wire may connect the motor to the electrical power source. In some embodiments, the power source may be arranged in the driving wheel.

The mobile appliance may further include a user-operable device, such as a switch, for operating the coupling device for decoupling the motor to the rim. A user-operable device may additionally or alternatively be provided for initiating the supply of power to the motor from the power source. One or more user- operable elements may be provided for shifting gears or otherwise varying the gearing optionally provided between the motor and the rim of the wheel, for example for operating the coupling device or clutch of the wheel.

Description of the drawings

Embodiments of the invention will now be further described with reference to the drawings, in which:

Fig. 1 illustrates a first embodiment of a motorised driving wheel according to the present invention;

Fig. 2 illustrates an embodiment of a suspension element supporting a motor for a motorised driving wheel in the first embodiment of the invention;

Fig. 3 illustrates the suspension element of Fig. 2 without the motor;

Figs. 4-6 illustrate a second embodiment of a motorised driving wheel according to the present invention;

Figs. 7 and 8 illustrate a coupling device for coupling and decoupling the motor drive force in a third embodiment of the invention;

Figs. 9a and 9b illustrate a wheel member according to a fourth embodiment of the invention; Fig. 10 illustrates a clutch device for achieving coupling and decoupling of the motor drive force;

Fig. 11 illustrates the clutch device of Fig. 10 being coupled to locking member;

Figs. 12a-12c illustrate coupling and decoupling of the locking member of Fig. 11;

Figs. 13a-13c illustrate a braking system;

Fig. 14 illustrates an elasticity element; and

Figs. 15a and 15b illustrate a steering element.

Fig. 1 illustrates an embodiment of a motorised driving wheel 1 comprising a circumferential rim 2, a motor 3 for producing a driving force, and a transmission system (not shown) for transmitting the driving force from the motor 3 to the circumferential rim 2.

The circumferential rim 2 forms an outer surface of an annular element 4 having an inner surface 5 which is tooted.

Furthermore, the driving wheel 1 comprises a suspension element 6 for supporting the motor 3. The suspension element 6 also supports three stabilising wheels 7 which are rotatably mounted at the suspension element 6, whereby respective outer circumferential surfaces of the stabilising wheels 7 are in contact with the inner surface 5 of the annular element 4. A groove (not shown) is provided along the outer circumferential surface of each of the stabilising wheels 7 in which grooves the tooth of the inner surface 5 of the annular element is situated so as to stabilise the suspension element 6 within the wheel 1. This allows for rotation of the wheel 1 without rotation of the suspension element 1. Furthermore, the suspension element 6 is non-rotatably mounted on the supporting shaft 8. The circumferential rim 2 defines an axis of revolution which is centred along the supporting shaft 8. The shaft 8 may have a circular or non-circular cross section. In the example shown in the drawings, the cross section and the corresponding aperture in the suspension element 6 are non-circular to prevent relative rotation between the suspension element and the shaft.

Additionally, the driving wheel 1 comprises a coupling device 9 for selectively coupling and decoupling the motor to the circumferential rim 2.

Fig. 2 illustrates the suspension element 6 with motor 3, stabilising wheels 7, supporting shaft 8 and coupling device 9, as described above.

Fig. 3 illustrates a part of the suspension element 6 and the coupling device 9 from a different angle. Furthermore, it illustrates parts of the transmission system for transmitting the driving force from the motor 3 to the circumferential rim 2, in this embodiment a first gearwheel 10 and a second gearwheel 11 both being mounted around a gear axis as indicated by the aperture 12 for the gear axel. The second gearwheel 11 is conical, and is arranged for interengagement with a third gearwheel (not shown), which is also conical, and which is mounted around a further gear axis being non-parallel to the first gear axis. In this embodiment, the further gear axis and the motor axis are substantially identical allowing for the third gearwheel and the motor 3 to be position end to end on one axel.

During operation of the wheel, the first gearwheel 10 engages the inner circumferential rim 5 shown in Fig. 1. The engagement of the first gearwheel 10 with the inner circumferential rim 5 can be selectively coupled or decoupled by means of the coupling device 9.

In the embodiment of Figs. 4-6, the motorised driving wheel 101 comprises two parallel wheel members 102', each of which forms a circumferential rim portion 102. At least one of the wheel members 102' is secured to a central driving axle 114 (cf. Fig. 6), which is driven by the motor 103 as follows. The output shaft 103' of the motor is a worm shaft engaging a fourth gearwheel 111. The fourth gearwheel 111 is mounted on an intermediate driving shaft 112, supporting a fifth gearwheel 110. The fifth gearwheel 110 drives a sixth gearwheel 113, mounted on the central driving axle 114. The motor 103 is supported by suspension element 106. The central driving axle 114 may drive both wheel members 102' or only one of them. In the latter alternative, the non-driven wheel member 102' is preferably idling.

For illustrative purposes, one of the wheel members 102' as well as the motor with its driving axle have been removed in Fig. 6. In order to facilitate freewheeling of the wheel members 102', the transmission system may be arranged to decouple the motor from the central driving shaft 114. For example, a mechanism may be provided for taking the fifth gearwheel 110 out of engagement with the sixth gearwheel 113 or for decoupling one of the fifth and sixths gearwheels 110, 113 from the respective one of shafts 112 and 114.

Figs. 7 and 8 illustrate a third embodiment of a motorised driving wheel 201. The driving wheel 201 comprises two parallel side frames 215. For illustration purposes only one of the side frames 215 is shown. The output shaft of the motor is a worm shaft (not shown) engaging a fourth gear wheel 211. The driving wheel 201 comprises a motor frame 216 being attached to the side frames 215. Furthermore, the driving wheel comprises a wheel member 202', which forms a circumferential rim portion 202.

The side frame 215 comprises three suspension rollers 217. A groove 218 is provided along the outer circumferential surface of each of the suspension rollers 217 in which grooves an inner surface 220 of the wheel member 202' is situated so as to stabilise the motor 203 within the wheel 201. This allows for rotation of the wheel 201 without rotation of the motor 203.

Drive force is transferred from the motor 203 to the circumferential rim 202 via the output shaft (not shown) and the gear wheel 211. The gear wheel 211 is in engagement with a toothed inner surface (not shown) of the wheel member 202'. In order to allow for freewheeling of the driving wheel 201 the wheel comprises a freewheeling axel 219 with a freewheeling roller 220. The freewheeling roller 220 is eccentrically mounted on the freewheeling axel 219. When turning the freewheeling axel 219 about 45 degrees, the motor frame 216 is moved and the output shaft will thus disengage the gear wheel 211 allowing for freewheeling of the wheel 201. Turning the freewheeling axel 219 back to its initial position, the motor frame 216 is returned to its initial position and the output shaft will thus engage the gear wheel 211 again allowing for transmission of motor drive force to the circumferential rim 202.

Figs. 9a-15 illustrate a fourth embodiment of a driving wheel 301 according to the invention.

Figs. 9a and 9b illustrate a wheel member 302' forming a circumferential rim portion 302. The wheel member 302' is illustrated from both sides. At one side (see Fig. 9a), the wheel member 302' comprises a substantially circular indentation 321, while at the other side (see Fig. 9b), the wheel member 302' comprises a substantially circular protrusion 322.

The circular aperture 323 in the middle of the wheel member 302' is for the central driving axel 314 (see e.g. Fig. 12) around which the wheel member 302' rotates.

In the indentation 321, three locking indentations 324 are positioned. The locking indentations 324 are used to lock the wheel member 302' to a fourth gear wheel 311 (see Fig. 11).

Fig. 10 illustrates a fourth gear wheel 311 in the form of a worm wheel. It should be understood, that the worm wheel may in another embodiment be replaced by a toothed gear wheel, while the output shaft in the form of a worm shaft may be replaced by a toothed rack. Other transmission systems may also be applicable. The gear wheel 311 comprises three locking apertures 325. The locking apertures 325 are together with the indentations 324 in the wheel member 302' (see Fig. 9a) used to lock the wheel member 302' to the gear wheel 311.

The gear wheel 311 comprises a fixation member 326 which is non-rotatable attached to the gear wheel 311. The fixation member 326 comprises four notches 327, each being formed as a triangle. In each of the notches 327 is positioned a roller 328 which is removable and not attached to neither the fixation member 326 nor to the gear wheel 311. In another embodiment, another number of rollers and notches may be applicable.

The circular aperture 323' in the middle of the gear wheel 311 is for the central driving axel (see e.g. Fig. 12) around which the wheel member 302' and the gear wheel 311 rotate.

When mounted on the central driving axel 314, the gear wheel 311 and the wheel member 302' are positioned adjacent to each other, closely but without contact between them to limit or even avoid frictional forces there between. The fixation member 326 is positioned in the indentation 321 so that the outer surface 326' of the fixation member 326 is in close to the inner surface 321' of the indentation 321. The rollers 328 are positioned in the notches 327.

When motor drive force is transmitted to the gear wheel 311, the gear wheel rotates around the central driving axel 314. Rotation of the gear wheel 311 will force the rollers 328 to move within the notches 327 to the opposite end of the triangle defining the notches 327 as indicated by the arrow 329. At this position, the rollers are pressed towards the inner surface 321' of the indentation 321 of the wheel member 302' (see Fig. 9a), while still in contact with the fixation member 326.

When the rollers 328 are pressed towards the inner surface 321', the gear wheel 311 and the wheel member 302' are connected to each other, and the motor drive force is transmitted to the wheel member 302' which rotates together with the gear wheel 311. If the speed of the wheel member 302' exceeds the speed of the gear wheel 311, the rollers 328 return to their initial positions in the notches 327 where they are not pressed towards the inner surface 321' of the indentation 321 of the wheel member 302', thereby allowing for freewheeling of the wheel member 302'. Thus, the circumferential rim 302 is released from motor drive force engagement.

If the speed of the wheel member 302' decreases, the rollers 328 move within the notches 327 to again bias towards the inner surface 321' of the indentation 321 of the wheel member 302' to allow for motor drive force transmission to the circumferential rim 302.

Fig. 11 illustrates the gear wheel 311 and a locking member 330. The locking member 330 comprises two discs 331 and three locking pins 332. The number of locking pins may be different in another embodiment.

The two discs 331 are non-removably connected to the locking pins 332. As illustrated, the locking pins 332 can be inserted into the locking apertures 325 of the gear wheel 311. The position of the locking member 330 relative to the gear wheel 311 is variable.

In Fig. 11, the locking pins 332 protrude through the locking apertures 325 thereby allowing for protrusion into the locking indentations 324 of the wheel member 302'. This will lock the wheel member 302' to the gear wheel 311.

When the wheel member 302' is locked to the gear wheel 311, freewheeling as described above is not possible. If an appliance incorporating the driving wheel is to be moved in this situation where freewheeling is impossible without the use of the motor, the motor is driven by the wheel member 302'.

Freewheeling is possible when having a greater distance between the locking member 330 and the gear wheel 311, a distance ensuring that the locking pins 332 do not protrude through the locking apertures 325 into the locking indentations 324 of the wheel member 302'. The locking member 330 may also be used to allow for reverse rotation of the wheel member 302'. This is illustrated in Figs. 12a-12c.

Fig. 12a illustrates the locking member 330 with the locking discs 331 and the locking pins 332 in freewheeling position, i.e. the locking pins 332 do not protrude through the gear wheel 331 and hence the wheel member 302' is not locked to the gear wheel 311.

When the locking handle 333 is moved from an upright position as illustrated in Fig. 12a downwards to a lower position as illustrated in Figs. 12b and 12c, the locking member 331 is moved to the right as illustrated by the arrow 334. Fig. 12b illustrates an intermediate position of the locking member 330, whereas Fig. 12c illustrates the final locking position of the locking member 330, in which the gear wheel 311 and the wheel member 302' are locked to each other.

When the wheel member 302' and the gear wheel 311 are locked to each other it is possible to reverse rotation of the wheel member 302' and thus the circumferential rim 302 by reversing rotation of the output shaft 334.

Figs. 12a-12c further illustrate the central driving axel 314 around which the wheel member 302' and the gear wheel 311 rotate.

Furthermore, a common frame 335 is illustrated. This is only for illustration purposes, as more of the features illustrated may be built into the driving wheel 301 and some other features may be part of a mobile appliance incorporating the driving wheel 301. In some embodiments, all the illustrated features may be built into the driving wheel 301.

A braking system 336 is also illustrated in Fig. 12a-12c. This embodiment of a braking system 336 is illustrated in detail in Figs. 13a-13c.

By the illustrated braking system 336 it is possible to decrease the rotational speed of the circumferential rim 302 by applying friction forces directly on to the wheel member 302' forming the circumferential rim portion 302. The braking system 336 comprises a gripping device which comprises two gripping arms 337a, 337b acting as a jaw which can grip around the substantially circular protrusion 322 of the wheel member 302' (see Fig. 9a and Fig. 12a), when activated.

The gripping arms 337a, 337b are positioned so that they permanently at least partly encircle the protrusion 322 of the wheel member 302'. The gripping arms are rotatably attached to the frame 335 by an attachment structure 338, e.g. an axel with a bolt at each end.

The braking system 336 is activated by the brake handle 339 (see Figs. 13b+c). The brake handle 339 is attached to a brake axel 340 which may be rotated approximately 45 degrees by movement of the brake handle 339. At a lower position of the brake axel 340 is the brake activator 341 attached. The brake activator 341 is in the illustrated embodiment oval and is positioned in the activator indentation 342 defined by an indentation in an upper end of each of the gripping arms 337a, 337b.

Fig. 13b illustrates the braking system 336 in braking mode, i.e. the lower end of the two gripping arms 337a, 337b are moved towards each other to grip around the protrusion 322 by tilting them around their attachment structure 338. The gripping arms 337a, 337b are tilted, as the oval brake activator 341 presses the upper ends of these arms 337a, 337b away from each other.

In Fig. 13c the braking system is deactivated, as the brake handle 339 is turned back to its initial position. The oval form of the brake activator 341 ensures that the upper ends of the gripping arms 337a, 337b are no longer presses away from each other. The spring 343 facilitates that the gripping arms 337a, 337b are tilted back to their initial position when not activated.

In the embodiment illustrated in Fig. 14 and Figs. 15a+b, the driving wheel is illustrated by one side frame 315 without illustration of the transmission system, the motor, etc. In some applications, it is an advantage if the driving wheel comprises a shock absorbing system being capable of dampening the influences on the wheel during rotation of the circumferential rim, e.g. when the driving wheel strikes a stone.

Fig. 14 illustrates a part of an elasticity element being adapted to elastically suspend the driving wheel. The elasticity element is movably attached to the side frame 315. The elasticity element comprises a spring 344 and an upper and lower block 345a, 345b. Furthermore, the elasticity element comprises an attachment member 346 to which the remainder parts of the driving wheel can be attached via the two protruding elements 346a, 346b.

The attachment member 346 is attached to the two blocks 345a, 345b via two axels (not shown) which extend through the side frame 315. The attachment member 346 is positioned in an indentation in the side frame 315, the indentation being higher than the height of the attachment member 346 and therefore provides a free space in which the attachment member is allowed to move up and down. Furthermore, the lower block 345b is attached to the spring 344. During movement of the driving wheel this elasticity element can act as a shock absorbing system, as the influence on the side frame 315, e.g. from a stone, can compress the spring 344 to allow movement under influence of a spring-force of the attachment structure 346 relative to the remainder part of the driving wheel or relative to an appliance being driven by the wheel.

In order to facilitate turning of a mobile appliance incorporating the driving wheel, the driving wheel illustrated by a side frame 315 in Figs. 15a+b comprises a steering element 347 being adapted to change the angle between the axis of revolution and a suspension structure for the wheel.

The steering element 347 is rotatably attached to the attachment member 346 via the protruding elements 346a, 346b and two bolt and nut connections 348 which together act as two hinges allowing the wheel to turn relative to a mobile appliance which can be connected to the suspension structure 349.

Claims

1. A motorised driving wheel comprising:

- a circumferential rim defining an axis of revolution;

- a transmission system for transmitting the driving force from the motor to the circumferential rim; characterised in that

- the axis of revolution and the motor axis are non-parallel; and in that - the transmission system is arranged to transform rotation of said output shaft around the motor axis into rotation of the circumferential rim around the axis of revolution.

2. A driving wheel according to claim 1, wherein the axis of revolution of the rim extends transversely to the motor axis.

3. A driving wheel according to claim 2, wherein the axis of revolution of the rim is substantially orthogonal to the motor axis.

4. A driving wheel according to any of the preceding claims, wherein the motor comprises a power connection element for receiving an electrical driving power from an external power source.

5. A driving wheel according to any of the preceding claims, wherein the circumferential rim forms an outer surface of an annular element, an inner circumferential surface of which is engaged by a first gearwheel.

6. A driving wheel according to claim 5, wherein said first gearwheel has an axis of rotation, which is substantially parallel to the axis of revolution of the circumferential rim.

7. A driving wheel according to any of claims 1-4, wherein the circumferential rim forms an outer surface of at least one wheel member, which is centrally driven by a central driving axle, which in turn is driven by the motor.

8. A driving wheel according to claim 7, wherein the motor output shaft drives a fourth gearwheel mounted to an intermediate driving shaft, said intermediate driving shaft supporting a fifth gearwheel, engaging a sixth gearwheel mounted to and driving said central driving shaft.

9. A driving wheel according any of the preceding claims, wherein the circumferential rim spans a cylinder, and wherein the motor is entirely contained within the cylinder.

10. A driving wheel according to claim 9, wherein said cylinder is closed at both ends.

11. A driving wheel according to any of the preceding claims, wherein the transmission system comprises a coupling device for selectively coupling and decoupling the motor drive force to the rim.

12. A driving wheel according to claim 11, wherein the coupling device comprises at least one clutch for achieving said coupling and decoupling.

13. A driving wheel according to claim 12, wherein the at least one clutch is arranged to provide motor drive force transmission to the rim only when the rim is not rotating at a higher speed than a driving speed set by the rotational speed of the output shaft, the clutch being further arranged to release the rim from motor drive force engagement when the rim is rotating at a higher speed than said set driving speed.

14. A driving wheel according to any of the preceding claims, further comprising a braking system activateable to decrease the speed of rotation of the circumferential rim.

15. A driving wheel according to claim 11 and 14, wherein the braking system is activateable to decrease the speed of rotation of the circumferential rim only when the motor drive force is decoupled from the rim.

16. A driving wheel according to claim 14 or 15, wherein the braking system comprises a gripping device adapted to grip around at least a part of a wheel member to decrease the speed of rotation of the rim.

17. A driving wheel according to any of the preceding claims, wherein at least one of the motor and the transmission system is arranged to drive the rim in a first, forward direction and in a second, reverse direction.

18. A driving wheel according to any of the preceding claims, further comprising an elasticity element being adapted to elastically suspend the motor.

19. A driving wheel according to any of the preceding claims, further comprising a steering element being adapted to change the angle between the axis of revolution and a suspension structure for the wheel.

20. A mobile appliance comprising at least one wheel according to any of the preceding claims.

21. A mobile appliance according to claim 20, further comprising an electrical power source for said motor, the power source being arranged externally with respect to the at least one wheel.