Patent Description:
Such hub systems, for instance conventional bike hub systems, are often provided with a coaster brake arrangement.

For example, hub systems with a coaster brake arrangement are known which comprise: a hub shaft; a driving member being rotatably mounted with respect to the hub shaft; a hub shell being rotatably mounted with respect to the hub shaft; a brake shoe arranged for engaging the hub shell such as to be coupled with said hub shell temporarily; a brake anchor arranged to be fixedly attached to a frame of a vehicle; and a coupling element arranged for enabling coupling between the driving member and the hub shell in a first position of said coupling element, and for enabling coupling between the brake anchor and the hub shell in a second position of the coupling element.

Such hub systems are known from practice. For example, pedal driven go-karts provided with such hub system provided with a coaster brake arrangement have been sold by the company Berg Toys.

The company Berg Toys sold for instance go-karts, wherein the brake anchor of the hub system is provided with a freewheel device. Said hub system is called a BFR hub system. It is noted that BFR stands for Brake, Forward and Reverse. Said BFR hub system allows a driver to drive forwards by pedalling forwards, to coast with the pedals remaining static when the vehicle is already rolling forwards, to brake by pedalling backwards slightly thereby activating an integrated coaster brake which comprises the brake shoe, and - due to the freewheel device - to drive backwards by pedalling further backwards after having braked.

Vehicles, such as go-karts, provided with said BFR hub system normally have a driving axis rotatably arranged in a vehicle frame, said driving axis normally being provided with pedals and a driving chain-wheel, which generally is coupled with a driven sprocket-wheel by means of a drive chain. Commonly, said driven chain-wheel is positioned around the hub shaft of the hub system, which hub shaft is fixed in rotational direction with respect to the vehicle frame, at a first lateral side of a hub shell of the system. At a second lateral side of the hub shell, the brake anchor is fixedly attached to the frame. Further, said driven sprocket-wheel is coupled to the driving member of the hub system, thereby enabling that rotational motion of the pedals and corresponding rotational motion of the driving member can make the hub shell to rotate forwards in order to drive forwards, can brake the hub shell, and can make the hub shell to rotate backwards subsequently in order to drive backwards. In order to pass the rotational motion of the hub shell, which hub shell is thus provided between the driven sprocket-wheel and the brake anchor, on to a wheel of the vehicle, a second driving chain-wheel is fixedly connected to said hub shell. By means of a second chain, said second driving chain-wheel is coupled with a second driven sprocket-wheel fixedly provided on a driven axis for driving at least one wheel, for example a left rear wheel, of the vehicle.

An advantage of a conventional BFR hub system over a normal coaster-brake hub system can lie in that such BFR hub system cannot only allow driving by pedalling forwards, coasting and braking, but can also allow a driver to drive rearwards after having braked.

However, disadvantages of a conventional BFR hub system may lie in that vehicles provided with such a hub system are normally of relatively complex design, e.g. due to the two separate drive chains. Further, the assembly and/or maintenance of the hub system and/or the vehicle, and/or (re-)adjustment of parts can be relatively difficult, time-consuming, error-prone and/or labour-intensive.

<CIT> discloses a go-cart with a BFR system in which a hub shaft is fixed to the frame. In this known system a roller brake is provided between the hub shaft and the hub shell whereas also a brake anchor is provided. The brake anchor and the roller brake are provided at the same lateral side of the driving member of the BFR system.

<CIT> discloses a bicycle hub having a multi speed-change mechanism and a braking mechanism which act by back-pedalling, wherein the hub shaft is fixed to the bicycle frame, and wherein, contrary to conventional multi-speed transmission bicycle hubs with a coaster brake, the hub is free from any braking action when the bicycle is pulled backwardly. It is noted that said hub of <CIT> comprises a hub shaft (fixed shaft <NUM>), a driving member (sprocket <NUM>) being rotatably mounted with respect to the hub shaft (fixed shaft <NUM>), a hub shell (hub shell <NUM>) being rotatably mounted with respect to the hub shaft (fixed shaft <NUM>), and brake shoes (brake shoes <NUM>) arranged for temporarily coupling said hub shell (<NUM>) with the hub shaft (fixed shaft <NUM>), wherein the hub shaft (fixed shaft <NUM>) is fixedly attached to a frame (bicycle frame F) of the bicycle, wherein, upon braking, each of the brake shoes (<NUM>) is temporarily rotationally coupled to said fixed hub shaft (<NUM>) by means of frictional forces between said brake shoes (<NUM>) and a brake cone (brake cone <NUM>) mounted on said fixed hub shaft (<NUM>), wherein said temporary rotational coupling between the brake shoes (<NUM>) and the hub shaft (<NUM>) is located at a first lateral side of the driving member (sprocket <NUM>), and the hub shaft (<NUM>) is rotationally fixated to the frame (F) at a second location located at a second lateral side of the driving member (<NUM>) and opposite of the first lateral side of said driving member (<NUM>), wherein said hub of <CIT> further comprises a rotational coupling comprising a freewheel device, which is physically located between the location of the brake shoes (<NUM>) and the location at which the hub shaft is fixed to the frame (F), but which freewheel device comprising rotational coupling does not rotationally couple the brake shoes (<NUM>) to the frame (F) of the bicycle.

An object of the present invention is to provide an alternative hub system and/or an alternative vehicle, especially a go-kart and/or a chain driven or belt vehicle, preferably for a child. In particular, it is an object of the present invention to alleviate or solve at least one disadvantages of a conventional hub system, such as a BFR hub system, especially one of the disadvantages mentioned above. More in particular, the invention aims at providing a hub system, wherein at least one of the disadvantages of a conventional hub system is counteracted or advantages there above are obtained. Especially, the invention aims at providing a hub system which is arranged such that a vehicle provided with such hub system can be of relative simple design. In embodiments, the invention aims at providing a hub system which can enable that a vehicle provided therewith can allow driving forwards by pedalling forwards, can allow coasting, can allow braking, and can also allow driving rearwards after a user has braked, preferably without said vehicle having a relative complex design and/or without said vehicle being provided with two separate drive chains and/or an additional axis.

In a first aspect, the present invention provides for a hub system which comprises: a hub shaft; a driving member being rotatably mounted with respect to the hub shaft; a hub shell being rotatably mounted with respect to the hub shaft; a brake shoe arranged for engaging the hub shell such as to be coupled with said hub shell temporarily; a brake anchor arranged to be fixedly attached to a frame of a vehicle; and a coupling element arranged for enabling coupling between the driving member and the hub shell in a first position of said coupling element, and for enabling coupling between the brake anchor and the hub shell in a second position of the coupling element, wherein the hub shaft is rotationally coupled to the brake shoe in at least one rotational direction at a first location located at a first lateral side of the driving member, and the hub shaft is also rotationally coupled to the brake anchor in at least one rotational direction at a second location located at a second lateral side of the driving member and opposite of the first lateral side of the said driving member, wherein the brake anchor and the brake shoe are rotationally coupled to each other by means of a rotational coupling, and wherein said rotational coupling between the brake anchor and the brake shoe comprises a freewheel device.

By rotationally coupling the hub shaft to the brake shoe in at least one rotational direction, and also rotationally coupling the hub shaft to the brake anchor in at least one rotational direction, the brake shoe and the brake anchor can be rotationally coupled to each other in at least one rotational direction via the hub shaft. Therefore, the hub system can enable that the brake shoe can be positioned at one lateral side of the driving member, and that that the brake anchor - coupled to said brake shoe by means of the hub shaft - can be positioned at the opposite lateral side of said driving member. As a result, the hub shell and/or a driven axis connected thereto can extend at a first lateral side of a sprocket-wheel attached to the driving member, whereas the brake anchor coupled to the hub shaft can be provided at the opposite lateral side of said sprocket-wheel. Hence, the rotational movement or stagnation of the hub shell can be passed onto a wheel attached to said hub shell and/or driven axis substantially directly, e.g. without needing a second driving chain-wheel, a second driven sprocket-wheel, and a second chain engaging with said sprocket-wheels.

A rotational coupling between the brake anchor and the brake shoe comprises a freewheel device, such as for instance a roller clutch or a rattle. As a result, after having braked, the then rotationally coupled driving member, brake shoe and hub shell may be allowed to rotate backwards with respect to the brake anchor. Hence, the hub system can go into reverse mode, such that the vehicle can be driven backwards.

Preferably, the freewheel device can be provided outside the hub shell. More preferably, said device can be provided between the brake anchor and the hub shaft. As a result, the diameter of the hub shell may for instance be limited to some extent. However, in alternative embodiments, the freewheel device may be located elsewhere, such as for instance between the brake shoe and the hub shaft.

Advantageously, the hub system may be arranged such that the freewheel device experiences a certain resistance when rotating in its freewheel direction due to friction between cooperating parts of said freewheel device, wherein a frictional force between said cooperating parts is larger than a frictional force between the coupling element and the driving member due to friction there between. As a result, it can be counteracted that the driving member is unintentionally coupled to the coupling element in rotational direction due to friction there between. Actually, it may be counteracted that the coupling element and therefore the hub shaft rotate backwards together with the backwardly rotating driving member, because a resistance force of the freewheel device can prevent this. It may thus be facilitated in a relatively elegant manner that the coupling element moves from its first position towards it second position when the driving member is rotated rearwards, in stead of that the hub shaft will freewheel, which usually may be highly unwanted. Hence, it can be facilitated in an elegant manner that a rearward movement of the driving member can cause the hub shell to brake and/or to rotate backwards in stead of that a rearward movement of the driving member only results in coasting or so-called freewheeling.

In embodiments, the hub system may comprise a resistance increasing element in order to enable that the frictional force between the cooperating parts of the freewheel device is larger than the frictional force due to the friction between the coupling element and the driving member. For example, said resistance increasing element may be a washer, such as a spring washer or lock washer, or any other suitable element, which may for instance be provided between two parts of the freewheel device which are moving with respect to each other during mutual rotation of said parts in a freewheeling direction of the freewheel device.

In embodiments said frictional force between cooperating parts as mentioned can be a static frictional force.

Advantageously, the hub shell can be attached to a driven axis for driving at least one wheel, or the hub shell can form a driven axis for driving at least one wheel. Hence, the driven axis of said wheel can be substantially in line with a central axis of the hub system. As a result, it can become superfluous to both mount a driven axis of the wheel to a vehicle frame and mount a parallel hub system to another part of the vehicle frame. Hence, a vehicle can be provided with a relatively simple frame.

The invention also relates to a vehicle, such as a chain driven vehicle or a belt driven vehicle, for example a go-kart for a child.

Advantageous embodiments of the invention are described below and in the appended claims.

By way of non-limiting examples only, embodiments of a prior art hub system and a prior art vehicle and embodiments of the present invention are now described with reference to the accompanying figures, in which:.

The embodiments disclosed herein are shown as examples only and should by no means be understood as limiting the scope of the appended claims in any way. In this description the same or similar elements have the same or similar reference signs.

At its left side, <FIG> shows a schematic top view of a part of a conventional vehicle <NUM> according to the prior art. Further, at its right side, <FIG> shows a schematic top view of a part of an inventive vehicle <NUM> according to an aspect of the invention. For clarity sake, no steering wheels or handle bars, no front wheels, and no seats or saddles are shown in <FIG>.

The prior art vehicle <NUM>, shown at the left side of <FIG>, is provided with a conventional hub system <NUM> according to the prior art, which can be better seen in <FIG>. Here, the prior art vehicle <NUM> has a frame <NUM> and a driving axis <NUM> rotatably arranged in said vehicle frame <NUM>. Said driving axis <NUM> is provided with pedals <NUM> and a driving chain-wheel <NUM>. The driving chain-wheel <NUM> is coupled with a driven sprocket-wheel <NUM> by means of a drive chain <NUM>. Said driven sprocket-wheel <NUM> is positioned around a hub shaft <NUM> of the hub system <NUM> at a first lateral side <NUM> of a hub shell <NUM>. Said hub shaft <NUM> is fixed in rotational direction with respect to the vehicle frame <NUM>, e.g. by mounting it to respective frame parts 22a. At a second lateral side <NUM> of the hub shell <NUM>, a brake anchor <NUM> is fixedly attached to the frame <NUM> by means of a respective frame part 22b. Further, said driven sprocket-wheel <NUM> is coupled to a driving member <NUM> of the hub system <NUM>. It is noted that the vehicle <NUM> and its hub system <NUM> are arranged such as to enable that rotational motion of the pedals <NUM> and corresponding rotational motion of the driving member <NUM> can make the hub shell <NUM> to rotate forwards in order to drive the vehicle <NUM> forwards, can brake the hub shell <NUM> in order to stop the vehicle <NUM>, and can make the hub shell <NUM> to rotate backwards after braking in order to drive the vehicle <NUM> backwards. In order to pass the rotational motion of the hub shell <NUM>, which hub shell is thus located between the driven sprocket-wheel <NUM> and the brake anchor <NUM>, on to a wheel <NUM> of the vehicle <NUM>, a second driving chain-wheel <NUM> is fixedly attached to said hub shell <NUM>. By means of a second chain <NUM>, said second driving chain-wheel <NUM> is coupled with a second driven sprocket-wheel <NUM> fixedly attached on a driven axis <NUM> for driving at least one wheel <NUM>, for example a left rear wheel <NUM>, of the vehicle <NUM>. It is noted that said driven axis <NUM> can substantially extend through a respective part 22d of the frame <NUM>.

The inventive vehicle <NUM> according to an aspect of the invention, which is partly shown in <FIG> and at the right side of <FIG>, comprises an inventive hub system <NUM> according to an aspect of the invention. A schematic cross section of said inventive hub system <NUM> is also shown in <FIG>. Said hub system <NUM> is for a vehicle <NUM>, for instance a pedal driven vehicle <NUM>, a chain driven vehicle <NUM> and/or a go-kart, especially a vehicle for a child. The system <NUM> comprises a hub shaft <NUM>, a driving member <NUM> being rotatably mounted with respect to the hub shaft <NUM>, and a hub shell <NUM> being rotatably mounted with respect to the hub shaft <NUM>, preferably at least partly by means of one or more bearings <NUM>, especially bearings provided directly or indirectly between said hub shell <NUM> and the hub shaft <NUM> or the driving member <NUM>. Further, the inventive hub system <NUM> comprises a brake shoe <NUM> arranged for engaging the hub shell <NUM> such as to be coupled with said hub shell <NUM> temporarily, at least in rotational direction. The hub system <NUM> also comprises a brake anchor <NUM> arranged to be fixedly attached to a frame <NUM> of a vehicle <NUM>, at least in rotational direction. As can be seen in <FIG> and <FIG>, the brake anchor <NUM> may for instance comprise one or more openings <NUM> which can be placed adjacent to a respective corresponding opening <NUM> in a respective frame part 22c, through which an attachments means such as a bolt can be mounted. However, the brake anchor <NUM> may alternatively be arranged to be fixedly attached to the frame <NUM> by other means. Furthermore, the hub system <NUM> comprises a coupling element <NUM> arranged for enabling coupling between the driving member <NUM> and the hub shell <NUM> in a first position of said coupling element <NUM>, and for enabling coupling between the brake anchor <NUM> and the hub shell <NUM> in a second position of the coupling element <NUM>. Preferably, the coupling element <NUM> can be rotatably mounted with respect to the hub shaft <NUM>, can be engaged with the driving member <NUM>, e.g. by means of cooperating thread <NUM>, <NUM>, and can be movable in an axial direction or a so-called lateral direction parallel to a longitudinal direction of the hub shaft <NUM> between said first position and said second position. It is noted that the hub shaft <NUM> is rotationally coupled to the brake shoe <NUM> in at least one rotational direction, and that the hub shaft <NUM> is also rotationally coupled to the brake anchor <NUM> in at least one rotational direction, preferably the same rotational direction. Preferably, the hub shaft <NUM> can neither rotate forwards with respect to the brake shoe <NUM>, nor forwards with respect to the brake anchor <NUM>. For example, the brake shoe <NUM> can be attached to the hub shaft <NUM> at least partly by means of positive locking. Here, the brake shoe <NUM> is positively locked to a brake cone <NUM> provided between the hub shaft <NUM> and the brake shoe <NUM>.

It is noted that the brake cone <NUM> can be substantially fixedly attached to the hub shaft <NUM>. Here, the brake cone <NUM> is provided with inner thread and is screwed onto a first end portion 5a of the hub shaft <NUM> which is provided with outer thread. Here, an end cap <NUM> provided with inner tread is subsequently screwed onto outer thread of the brake cone <NUM>. Said end cap <NUM> can counteract that the brake cone <NUM> can, during use of the hub system <NUM>, move further laterally along the hub shaft <NUM> in the direction of a second end portion 5b of the hub shaft <NUM> opposite the first end portion 5a, e.g. due to that the end cap 11a can abut an end face 5c of the hub shaft <NUM>.

In embodiments, the hub system <NUM> may further comprise a brake spring <NUM> arranged for biasing the coupling element <NUM> in a direction away from the brake shoe <NUM> and/or towards the first position of said coupling element <NUM>.

Advantageously, the brake shoe <NUM> can be coupled with the hub shaft <NUM>, e.g. rotationally coupled in at least one rotational direction, at a first location located at a first lateral side, e.g. the left side, of the driving member <NUM>, and the brake anchor <NUM> can be coupled with the hub shaft <NUM>, e.g. rotationally coupled in at least one rotational direction, at a second location, wherein the second location is located at a second lateral side of the driving member <NUM> and is located opposite of the first lateral side of said driving member <NUM>, e.g. its right side.

The brake anchor <NUM> and the brake shoe <NUM> are coupled to each other such that the coupling there between comprises a freewheel device <NUM>, such as for instance a roller clutch or a rattle <NUM>, <NUM>. Preferably, said freewheel device <NUM> can be provided outside the hub shell <NUM>, e.g. in order to save space in the hub shell <NUM>. More preferably, the freewheel device <NUM> can be positioned between the brake anchor <NUM> and the hub shaft <NUM>, such as is shown in <FIG>. However, in alternative embodiments, which fall within the scope of the appended claim set, but which alternative embodiments are not explicitly specified in the appended claim set, the freewheel device <NUM> can have another location. For example, the freewheel device <NUM> can be provided between the brake shoe <NUM> and the hub shaft <NUM> and/or within the hub shell <NUM>.

Advantageously, an inner portion <NUM> of the freewheel device can be substantially fixedly attached to the hub shaft <NUM>, especially to its second end portion 5b. For example, the inner portion <NUM> can be screwed onto the hub shaft <NUM>, preferably indirectly onto to the hub shaft <NUM> by screwing it onto a freewheel adapter element <NUM>, which may be screwed onto the hub shaft <NUM>. In embodiments, which fall within the scope of the appended claim set, but which alternative embodiments are not explicitly specified in the appended claim set, a second end cap 11b can be attached to the inner portion <NUM> of the freewheel device, thereby preventing that said inner portion <NUM> of the freewheel device can substantially move towards the hub shell <NUM> during use. In order to lock said inner portion <NUM> substantially with respect to the hub shaft <NUM>, at least in one axial direction, e.g. at least in a direction towards the hub shell <NUM>, the second end cap 11b can be screwed onto the freewheel adapter element <NUM>. Since the end cap 11b can abut an end face 5d of the hub shaft <NUM>, said end cap 11b can counteract that the inner portion <NUM> of the freewheel device can substantially move towards the hub shell <NUM> during use of the hub system <NUM>. Further, it is noted that the inner portion <NUM> of the freewheel device can in alternative embodiments, which fall within the scope of claim set, but which alternative embodiments are not explicitly specified in the appended claim set, be attached to the hub shaft <NUM> in other manners. For example, the inner portion <NUM> may be attached to the shaft <NUM> by means of a bolt extending through said shaft <NUM> and said inner portion <NUM>, the inner portion can be welded to the shaft <NUM>, or the inner portion <NUM> can be integrally formed on the hub shaft <NUM>. In yet a further alternative embodiment, which falls within the scope of appended claim set, but which alternative embodiment is not explicitly specified in the appended claim set, the end cap 11b can be an integral part of the inner portion <NUM>.

Advantageously, the hub system <NUM> may be arranged such that the freewheel device <NUM> can experiences a certain resistance when rotating in its freewheel direction due to friction between cooperating parts <NUM>, <NUM> of said freewheel device <NUM>, wherein a frictional force, such as a static frictional force, between said cooperating parts <NUM>, <NUM> is larger than a frictional force, such as a static frictional force, between the coupling element <NUM> and the driving member <NUM> due to friction there between. As a result, it can be counteracted that the driving member <NUM> is unintentionally coupled to the coupling element <NUM> in rotational direction due to friction there between. Actually, it may be counteracted that the coupling element <NUM>, and therefore also the hub shaft <NUM>, rotates backwards together with the backwardly rotating driving member <NUM>, because a resistance force of the freewheel device <NUM> can prevent this. It may thus be facilitated in a relatively elegant manner that the coupling element <NUM> moves from its first position towards it second position when the driving member <NUM> is rotated rearwards, in stead of that the hub shaft <NUM> will freewheel, which can be highly undesirable. Hence, it can thus be facilitated that a rearward movement of the driving member <NUM> causes the hub shell <NUM> to brake and/or to rotate backwards in stead of that a rearward movement of the driving member <NUM> only results in coasting or so-called freewheeling.

In embodiments, the hub system <NUM> may comprise a resistance increasing element <NUM> in order to enable that the frictional force, such as a static frictional force, between the cooperating parts <NUM>, <NUM> of the freewheel device <NUM> is larger than the frictional force, such as a static frictional force, due to the friction between the coupling element <NUM> and the driving member <NUM>. For example, said resistance increasing element <NUM> may be a washer <NUM>, such as a spring washer or lock washer, or any other suitable element, which may for instance be provided between two parts <NUM>, <NUM> of the freewheel device <NUM> which are moving with respect to each other during mutual rotation of said parts <NUM>, <NUM> in a freewheeling direction of the freewheel device <NUM>.

Additionally or alternatively, the hub system <NUM> may be arranged to limit frictional resistance between the coupling element <NUM> and the driving member <NUM>. For example, the cooperating thread <NUM>, <NUM> provided at these parts <NUM>, <NUM> may be relatively smooth, e.g. by providing at least one of them with at least a relatively smooth outer layer, e.g. comprising Teflon. As another example, these parts <NUM>, <NUM> may be relatively well lubricated.

It is noted that the hub system <NUM> can be provided in a vehicle <NUM>, such as for instance a go-kart for a child, a pedal driven vehicle, such as a chain or belt driven vehicle. The hub system <NUM> can for instance be mounted in a frame <NUM> of the vehicle <NUM>. As can be seen in <FIG>, a central axis <NUM> of the hub shell <NUM> and/or a central axis <NUM> of the hub system <NUM> can be in line with a central axis <NUM> of a driven axis <NUM> for driving at least one wheel <NUM>, for example a rear wheel, especially a left rear wheel, of the vehicle <NUM>.

In embodiments, the vehicle <NUM> can also comprise a driving axis <NUM> rotatably arranged in said vehicle frame <NUM>. Said driving axis <NUM> can for instance be provided with pedals <NUM> and/or a driving chain-wheel <NUM>. For example, said driving chain-wheel <NUM> can be coupled with a driven sprocket-wheel <NUM> of the hub system <NUM>, e.g. by means of a drive chain <NUM>. Preferably, the driving member <NUM> is provided with said sprocket-wheel <NUM> for cooperation with a drive chain <NUM>. Said sprocket-wheel10 can be fixed rotationally, and preferably also laterally or so-called axially, with respect to said driving member <NUM>.

Advantageously, the hub system <NUM> can be mounted to the frame <NUM> of the vehicle <NUM> at least partly by means of fixedly attaching its brake anchor <NUM> to the frame <NUM>.

Additionally or alternatively, the hub system <NUM> can be at least partly supported on bearings <NUM>, <NUM> by the frame <NUM>. In embodiments, the hub shell <NUM> and/or the driven axis <NUM> can be provided with at least one bearing element <NUM>, <NUM> for facilitating that the hub shell <NUM> and/or the driven axis <NUM> can be rotatably attached to the frame <NUM> of a vehicle <NUM>. For example, bearings <NUM>, e.g. one or more roller bearings <NUM>, may be provided between the driven axis <NUM> and the frame <NUM>. Alternatively or additionally, a bearing may be provided between the hub shell <NUM> and the frame. Additionally or alternatively, other parts of the hub system <NUM> can be supported on bearings. For example, the hub shaft <NUM>, e.g. at an end protruding from the hub shell <NUM> at the side of the brake anchor <NUM>, may be provided with a bearing element <NUM> for facilitating that the hub shaft <NUM> can be rotatably attached to the frame <NUM>, and/or the hub shaft <NUM> may be supported on one or more bearings <NUM> by the frame <NUM>. Although the latter bearing <NUM> is here provided indirectly on the hub shaft <NUM>, said bearing may in alternative embodiment be placed directly onto said hub shaft <NUM>.

The operation of a hub system <NUM> according to the invention will now be briefly described at the hand of <FIG>. Here, the hub system <NUM> is shown seen from the rear side of the hub system <NUM>, which can correspond with the rear side of the vehicle <NUM>. In the here shown exemplary embodiment, the driven sprocket-wheel <NUM>, which can be directly coupled to a driving chain-wheel <NUM> of a vehicle <NUM> by means of a drive chain <NUM>, is positioned at the right side of the hub shell <NUM>, and the brake anchor <NUM> is positioned at the right side of the driven sprocket-wheel <NUM>. It is noted that, during use, the brake anchor <NUM> is fixedly attached to the frame <NUM>. All the other parts of the hub system <NUM> may be mounted such as to be able to rotate around the central axis <NUM> of the hub system <NUM>. It is further noted that, except for the coupling element <NUM>, all hub system parts discussed above, may be prevented from moving laterally, e.g. axially, during use of the hub system <NUM>. When the driving member <NUM> is rotated forwards, e.g. by means of pedalling forwards, said driving member <NUM> moves the coupling element <NUM> to the first position in which said element <NUM> enables coupling, especially rotational coupling in at least one direction, between the driving member <NUM> and the hub shell <NUM>. For example the driving member <NUM>, which may be substantially cone-shaped and which can be a so-called driving cone <NUM>, may be provided with outer thread <NUM> engaging with inner thread <NUM> of the coupling element <NUM>, such that said driving member <NUM> can enable that the coupling element <NUM> moves laterally or axially with respect to the hub shaft <NUM>. Here, when the driving member <NUM> is rotated forwards, the coupling element <NUM> can move to the right. In embodiments, the coupling element <NUM> can move with a conical gripping surface <NUM> towards a corresponding conical gripping surface <NUM> of the hub shell <NUM>. As soon as the gripping surfaces <NUM>, <NUM> engage, the coupling element <NUM> will not substantially move laterally any further, but will rotate forwards together with the driving member <NUM>, thereby driving the engaged hub shell <NUM> forwards as well. Although the coupling element <NUM> and the hub shell <NUM> are here provided with said gripping surfaces <NUM>, <NUM>, it is noted that the hub system <NUM> may in alternative embodiments be arranged alternatively in order to allow that the coupling element <NUM> can engage with the hub shell <NUM> in the first position in such a way that they <NUM>, <NUM> are then coupled in at least one rotational direction, e.g. in such direction that the hub shell <NUM> rotates forwards when the coupling element <NUM> rotates forwards.

Moreover, it is noted that the hub shell <NUM> can be attached to a driven axis <NUM> for driving at least one wheel <NUM>. Alternatively, the hub shell <NUM> itself may form a driven axis <NUM> for driving said at least one wheel <NUM>. Here, the hub shell <NUM> is rotationally coupled to the driven axis <NUM>, in both rotational directions, by fixedly attaching them to each other. This can for instance be done by means of a bolt extending trough corresponding holes <NUM>, <NUM> in the driven axis <NUM> and hub shell <NUM>. In the embodiment shown, an adapter <NUM>, which can comprise a corresponding bore hole <NUM>, is positioned between the axis <NUM> and hub shell <NUM>, such that an axis <NUM> can be used which has a relatively small outer diameter with respect to an inner diameter of the hub shell <NUM>.

Furthermore, it is noted that the driven wheel <NUM> of the vehicle <NUM> can be rotationally coupled to the driven axis <NUM>. Hence, a rotational movement of the hub shell <NUM> can be passed on to said wheel <NUM>. Forward rotation of the hub shell <NUM> due to forward pedalling will thus result into forward rotation of the wheel <NUM>. Preferably, only one wheel <NUM> is driven by the driven axis <NUM>, thereby counteracting that the vehicle cannot be steered through a turn.

In embodiments, a freewheel device, such as for instance a rattle or roller clutch, can be provided between the coupling element <NUM> and the hub shell <NUM>, e.g. provided between their gripping surfaces <NUM>, <NUM> and/or formed at least partly by said gripping surfaces <NUM>, <NUM>. As a result, the hub system <NUM> may allow a user to coast with the vehicle <NUM>. This is, the hub shell <NUM> can then keep rotating forwards, when the vehicle is rolling forwards and the pedals <NUM> and the driving member <NUM> coupled therewith are for instance held stationary with respect to the frame <NUM>.

Further, the hub system <NUM> can be used to break. Thereto, when the driving member <NUM> is rotated backwards, e.g. by pedalling backwards, the coupling element <NUM> can be moved to a second position. Preferably, said second position can be axially offset from the first position. For example, the coupling element <NUM> can be moved laterally or so-called axially with respect to the hub shaft <NUM>, e.g. to the left, in order to be moved to said second position. In said second position, the coupling element <NUM> can enable coupling between the brake anchor <NUM> and the hub shell <NUM>. Advantageously, said coupling can for instance be enabled by pushing the coupling element <NUM> at least partly beneath a portion of the brake shoe <NUM> such that the brake shoe <NUM>, which may be resilient to some extent, bends towards an inner surface <NUM> of the hub shell <NUM>. Hence, the brake shoe <NUM> can grip the hub shell <NUM>, e.g. at least partly by means of friction, and can stop said hub shell from substantially rotating with respect to the brake shoe <NUM>, which brake shoe <NUM> can be kept from moving with respect to the coupling element <NUM> by means of cooperating gripping surfaces <NUM>, <NUM> thereof. Although the coupling element <NUM> and the brake shoe <NUM> are here provided with said gripping surfaces <NUM>, <NUM>, it is noted that the hub system <NUM> may in alternative embodiments, which fall within the scope of appended claim set, but which alternative embodiments are not explicitly specified in the appended claim set, be arranged alternatively in order to allow that the coupling element <NUM> can cooperate with the brake shoe <NUM> in the second position such that said brake shoe <NUM> can then be coupled with the hub shell <NUM>. It is noted that by stopping the hub shell <NUM> from moving forwards in this manner, the hub shell <NUM> becomes rotationally coupled, in the backward direction, with the driving member <NUM>. Here, the hub shell <NUM> is for instance rotationally coupled to the driving member <NUM> in said backward direction by means of the coupling element <NUM> and the brake shoe <NUM>. Since the hub shaft <NUM> is rotationally coupled to the brake shoe <NUM>, in at least one rotational direction, especially the backward direction, and preferably in both rotational directions, the hub shaft <NUM> will here be rotated backwards when the driving member <NUM> is rotated backwards after a user has braked the forward rotation of the hub shell <NUM>. It is noted that the hub shaft <NUM> is here coupled to the brake anchor <NUM> by means of freewheel device <NUM> which allows said hub shaft <NUM> to rotate backwards with respect to said brake anchor <NUM>. As a result, by pedalling backwards after having braked, a user can make the hub shell <NUM> to rotate backwards. This can thus result in that the driven axis <NUM> attached to the hub shell <NUM>, and the wheel <NUM> attached to the driven axis <NUM> will rotate backwards as well, thereby driving the vehicle <NUM> backwards.

For example, the vehicle <NUM> may be arranged such that another wheel of said vehicle is driven, for example its right rear wheel.

As a further example, in embodiments, the drive chain <NUM> can for instance be replaced by another transmission element for transmitting power from the driving axis <NUM> to the driving member <NUM>. For example, a drive belt may be provided, such as a teethed drive belt, and the chain-wheel and the sprocket-wheel may be replaced by corresponding pulleys or cog-wheels. As another example, the driving member <NUM> may be provided with a first gear wheel forming a connection element for cooperation with a second gear wheel forming a transmission element, e.g. for transmitting a movement of a driving axis <NUM> to said driving member <NUM>, substantially directly or indirectly.

Claim 1:
Hub system (<NUM>) for a vehicle (<NUM>), such as a chain or belt driven vehicle for example a go-kart for a child, comprising:
a hub shaft (<NUM>);
a driving member (<NUM>) being rotatably mounted with respect to the hub shaft (<NUM>);
a hub shell (<NUM>) being rotatably mounted with respect to the hub shaft (<NUM>);
a brake shoe (<NUM>) arranged for engaging the hub shell (<NUM>) such as to be coupled with said hub shell (<NUM>) temporarily;
a brake anchor (<NUM>) arranged to be fixedly attached to a frame of a vehicle (<NUM>); and
a coupling element (<NUM>) arranged for enabling coupling between the driving member (<NUM>) and the hub shell (<NUM>) in a first position of said coupling element (<NUM>), and for enabling coupling between the brake anchor (<NUM>) and the hub shell (<NUM>) in a second position of the coupling element (<NUM>),
wherein the hub shaft (<NUM>) is rotationally coupled to the brake shoe (<NUM>) in at least one rotational direction at a first location located at a first lateral side of the driving member (<NUM>), and the hub shaft (<NUM>) is rotationally coupled to the brake anchor (<NUM>) in at least one rotational direction at a second location located at a second lateral side of the driving member (<NUM>) and opposite of the first lateral side of said driving member (<NUM>),
characterized in that the brake anchor (<NUM>) and the brake shoe (<NUM>) are rotationally coupled to each other by means of a rotational coupling, and wherein said rotational coupling between the brake anchor (<NUM>) and the brake shoe (<NUM>) comprises a freewheel device (<NUM>).