NL2002815C2

NL2002815C2 - Freewheel arrangement for a vehicle, driving assembly and a vehicle, such as a chain driven vehicle comprising such a freewheel arrangement.

Info

Publication number: NL2002815C2
Application number: NL2002815A
Authority: NL
Inventors: Bas Roelofs; Albertus Hendrikus Heres; Mathijs Wit
Original assignee: Berg Toys B V
Priority date: 2009-04-28
Filing date: 2009-04-28
Publication date: 2010-10-29
Also published as: DE102010028073A1

Description

P87078NL00

Title: Freewheel arrangement for a vehicle, driving assembly and a vehicle, such as a chain driven vehicle comprising such a freewheel arrangement

The invention relates to a freewheel arrangement for a vehicle, such as a chain driven vehicle for example a go-kart for a child, the arrangement comprising a freewheel device with a first part connected to an axle connector adapted to receive a driving axle and a second part connected to a wheel 5 connector adapted to receive a wheel, wherein the second part of the freewheel device comprises a right-handed inner thread adapted to receive an outer thread of the wheel connector.

Such freewheel arrangements are known from practice and can be arranged between a wheel, such as a rear wheel, and a driving axle of a vehicle 10 such as a chain driven vehicle like a go-kart for a child. Such a vehicle can for instance be driven by pedals. Upon rotation of the pedals, the rear driving axle is rotated, which in turn rotates a rear wheel of the vehicle. In order to prevent the pedals to start rotating when the user of the vehicle stops rotating the pedals, a freewheel arrangement is provided between the rear wheel and the 15 driving axle. When the user stops rotating the pedals and thus the driving axle stops accordingly, the freewheel device allows for continuation of rotation of the rear wheel without the pedals continuing to rotate. The freewheel arrangement is commonly arranged on a left-hand wheel of the vehicle seen in a driving direction of the vehicle such that upon rotation of the left-hand 20 wheel, the connection between the freewheel device and the left-hand wheel tightens due to the right handedness of the screw thread of the connection. By common convention, right handedness is the default handedness of screw threads. Thus, driving the left-hand wheel of a vehicle using a left-hand freewheel device is advantageous with respect to manufacturing costs of the 2 freewheel arrangement and thus also for the total manufacturing costs of the vehicle.

However, in some cases the user may encounter problems driving and/or steering the vehicle due to the structure of the vehicle. For instance, 5 when the user of the vehicle is pulling the left side of the vehicle off the ground for performing stunts and the like or by driving across a terrain with an uneven ground surface, the left rear wheel may not be driven. Since the vehicle is only driven by the left-hand wheel the vehicle may become unsteerable.

10 Therefore, the object of the present invention is to provide a freewheel arrangement of the above-described type, wherein the advantages of the known freewheel arrangement are maintained and the disadvantages of the known freewheel arrangement are at least partly overcome. More in particular, it is an object of the invention to provide a vehicle that is better 15 steerable and/or drivable.

Thereto, according to a first aspect of the invention, the freewheel arrangement of the above described type is characterized in that between the second part of the freewheel device and the wheel connector an adapter 20 element is provided that is arranged such that the freewheel arrangement can be used between the driving axle and a right-hand wheel such that in use a connection between the freewheel device and the wheel connector stays in tact or tightens upon rotation of the wheel connector in a driving direction, wherein the adapter element comprises a right-handed outer thread connected to the 25 inner thread of the second part of the freewheel device, wherein the adapter element comprises a left-handed inner thread connected to a left-handed outer thread of the right hand wheel connector.

By providing the adapter element between the second part of the freewheel device and the wheel connector, the freewheel arrangement can be 30 used for driving and freewheeling of the right-hand wheel of the vehicle 3 without the risk of disconnection of the wheel connector from the freewheel device. The adaptor element thus provides that a commonly available freewheel device can be used on a left-hand side of the vehicle as well as on the right-hand side of the vehicle to provide a freewheel possibility for the 5 respective wheels in case the user stops actively driving the vehicle or when the wheels are rotating faster than the speed of the first part of the freewheel device with respect to the second part of the of the freewheel device. Consequently, a right-hand freewheel arrangement is provided that can be manufactured at relatively low costs while using as many standard parts 10 available. With such a freewheel arrangement it is possible to provide a vehicle, such as a chain driven vehicle, like a go-kart, with two driven rear wheels, that can be driven at the same time but also can be driven independently. The left-hand wheel may be driven in case the right-hand wheel is not connected to the ground in case of performing stunts and vice 15 versa. Furthermore, in case the vehicle is steered to turn right, the left-hand rear wheel is able to freewheel while the right-hand rear wheel may be driven. In case the vehicle is steered to turn left, the right-hand rear wheel is able to freewheel while the left-hand rear wheel may be driven. After returning to a direction straight ahead, both wheels are driven again. Consequently, with the 20 freewheel arrangement according to the invention a vehicle may be provided that can be used for different kinds of activities thereby reducing the risk of the vehicle becoming unsteerable due to said activities.

It is noted that the handedness of the thread may be determined by the orientation of the helix of the thread. The helix of a right-handed thread is 25 oriented such that seen from above in an axial direction, it is tightened by turning it in a clockwise direction and loosened by turning it in a counter clockwise direction. Similarly, the helix of a left-handed thread is oriented such that seen from above in an axial direction, it is tightened by turning it in a counter clockwise direction and loosed by turning it in a clockwise direction. 30 4

The adapter element can be positioned easily in a receiving cavity of the second part of the freewheel device by screwing the outer thread of the adapter element into the inner thread of the freewheel device.

5 In order to prevent the adapter element of displacing with respect to the freewheel device during rotation of the wheel connector, the adapter element comprises, according to a further elaboration of the invention, a securing means for securing the adapter element to the freewheel device. Such a securing means may for instance comprise a flange extending radially 10 outward at least partly along an outer circumference of an adapter element body. According to a further aspect of the freewheel arrangement according to the invention, the securing means is positioned between the driving axle connector and the second part of the freewheel device. With such a structure of the adapter element, the connection of the adapter element and the second 15 part of the freewheel device tightens upon rotation of the right-hand wheel. When the right-hand wheel is rotating in a driving direction, the connection of the wheel connector and the inner thread of the adapter element tightens. Consequently, in response thereto, the natural behaviour of the adapter element is to move in an outward direction from the driving axle towards the 20 wheel. By moving in that outward direction, the securing means of the adapter element will contact the side of the second part of the freewheel device that faces the driving axle connector. Thus, the outward movement of the adapter element with respect to the second part of the freewheel device results in a tighter contact between the flange and the second part of the freewheel device 25 preventing the adapter element from displacing any further.

Said adapter element may comprise a substantially cylindrical body which provides for a tight connection between the entire outer thread of the wheel connector and the entire inner thread of the freewheel device facing the wheel connector.

5

In order to further enhance the tightness of the connection between the adapter element and the second part of the freewheel device, it may be advantageous according to a further elaboration of the invention, if a length of the adapter element is substantially equal to a length of the inner thread of 5 the freewheel device seen in a direction substantially parallel to a rotational axis of the freewheel device.

Preferably, the freewheel device is a commonly available freewheel device with a right-handed inner thread, being a freewheel device with a 10 default handedness for screw threads. By using such a commonly available freewheel device, the total costs of the freewheel arrangement according to the invention, thus for use on a right-hand wheel of a vehicle, are comparable to the costs of the left hand freewheel arrangement that is commonly used on vehicles such as go-karts for kids and the like vehicles. By providing the 15 adapter element, there is no need for specially manufactured freewheel devices having a left-handed inner thread in the second part. Such freewheel devices are special products and therefore relatively expensive parts.

The invention also relates to a driving assembly for a vehicle such as 20 chain driven vehicle, for example a go-kart for a child, the driving assembly comprising a driving axle provided with a right-hand freewheel arrangement according as above described at a first right-hand end of the axle and with a further left-hand freewheel arrangement provided at a second left-hand end seen in a driving direction, wherein a wheel connector of the further freewheel 25 arrangement is directly connected to a second part of a freewheel device of said further arrangement. Such a driving assembly enables a vehicle to have two independently driven rear wheels that may freewheel when necessary. As mentioned before, the freewheel arrangement according to the invention enables the right-hand rear wheel to be driven independently from the left-30 hand rear wheel. With the above mentioned driving assembly, that comprises 6 a freewheel arrangement according to the invention and a left-hand freewheel arrangement known from practice, the rear wheels of the vehicle can he driven at the same time, providing a two wheel driven vehicle, which rear wheels at the same time are adapted to be driven independently when necessary. In case 5 the left-hand rear wheel can not be driven due to external factors, for instance the kind of activity the vehicle is used for, the right-hand rear wheel is automatically driven and vice versa. Activities that may prevent one of the rear wheels to be driven may for instance comprise stunt performance of the vehicle. In case one of the rear wheels can not be driven, said respective rear 10 wheel may freewheel when necessary due to the construction of the freewheel arrangement. This may be convenient for instance when steering the vehicle to turn left or to turn right.

Furthermore, the invention relates to a vehicle, such as a chain 15 driven vehicle for example a go-kart for a child, comprising a driving assembly as mentioned above and/or a freewheel arrangement as described before. Such a vehicle provides for similar effects and advantages as described with the freewheel arrangement and the driving assembly.

20 Further advantageous embodiments of a freewheel arrangement, a driving assembly and a vehicle comprising such an arrangement and/or such an assembly according to the invention are set forth in the dependent claims. To explain the invention, exemplary embodiments thereof will hereinafter be described with reference to the accompanying drawings, wherein: 25 Fig. 1 schematically shows a perspective view of a driving assembly according to an embodiment of the invention;

Fig. 2 schematically shows a cross sectional view of a freewheel arrangement for a right-hand wheel according to an embodiment of the invention; 7

Fig. 3a schematically shows a vehicle with a driving assembly as shown in Fig. 1 when turning left; and

Fig. 3b schematically shows a vehicle with a driving assembly as shown in Fig. 1 when turning right.

5

It is noted that similar parts in the different figures are referred to by similar reference numerals.

Figure 1 shows a driving assembly 1 for a vehicle V (see Figs. 3a and 10 3b) such as a chain driven vehicle for example a go-kart for a child. The driving assembly 1 comprises a driving axle 2 provided with transmission means 4, in this case a gear-wheel, for driving the driving axle 2 in a rotational driving direction d. The transmission means 4 are in use rotated by a driving element, such as a chain (not shown) that may be connected to pedals, resulting in 15 rotation of the wheels W3, W4 provided on the driving axle 2. The driving assembly 1 further comprises a right-hand freewheel arrangement 6 (see also Fig. 2) provided at a right-hand side 2a of the axle 2 and a left-hand freewheel arrangement 8 provided at a left-hand side 2b of the axle 2.

It is noted that the wording “right-hand” and “left-hand” throughout 20 the application should be related to the driving direction D of the vehicle.

The freewheel arrangements 6, 8 comprise a commonly available freewheel device 10 having an first outer part 11 and a second inner part 12. The outer part 11 of the freewheel device 10 is connected to an axle connector 14. The axle connector 14 has a receiving cavity 15 that is adapted to receive 25 the driving axle 2, more specifically to receive the drive bush 3 connected to the driving axle 2. The freewheel arrangements 6, 8 further comprise a wheel connector 16,18 having a wheel bush 19 adapted to receive a wheel W3, W4 (see Figs 3a and 3b) 8

In Figure 2 an embodiment of the right-hand freewheel arrangement 6 according to the invention is shown. The freewheel arrangement 6 comprises a commonly available freewheel device 10. The first outer part 11 of the freewheel device 10 is connected to the axle connector 14, more specifically to a 5 flange 17 of the axle connector 14. The second inner part 12 of the freewheel device 10 is rotatably arranged with respect to the outer part 11. Upon rotation of the first outer part 11 of the freewheel device 6 in a driving direction d, the second inner part 12 is rotated in said driving direction d as well. When rotation of the outer part 11 is stopped, for instance because the 10 user has stopped rotating the pedals, the inner part 12 can freewheel in the driving direction d. The inner part 12 may also freewheel if the wheel W4 is rotating faster than the driving axle 2, as will be explained with Figures 3a and 3b later on.

The second part 12 of the freewheel device 10 comprises a right-15 handed inner thread 20, as this is the default handedness for screw threads determined by common convention. The wheel connector 16 comprises a left-handed outer thread 22 on the part 24 of the connector 16 facing the freewheel device 10. The outer thread 22 is a left-handed outer thread because rotation of the driving axle 2 would cause a right-handed thread to loosen rather than to 20 tighten due to fretting induced precession. The wheel connector 16 further comprises a wheel bush 19 that is adapted to receive a wheel W4. In this embodiment of the invention, the wheel bush 19 has a substantially square cross section.

25 Between the second part 12 of the freewheel device 10 and the outer thread 22 of the part 24 of the wheel connector 16, an adapter element 26 is provided, that is adapted to enable connection of the left-handed outer thread 22 of the wheel connector 16 to the right-handed inner thread 20 of the second part 12 of the freewheel device 10, such that in use the connection between the 30 freewheel device 10 and the wheel connector 16 tightens upon rotation of the 9 right-hand wheel connector 16 in a driving direction d. The adapter element 26 has a substantially cylindrical body 28 comprising a right-handed outer thread 30 and a left-handed inner thread 32. The inner thread 32 is connected to the outer thread 22 of the wheel connector 16 and the outer thread 30 is connected 5 to the inner thread 20 of the second part 12 of the freewheel device 10. The adapter element 26 further comprises a securing means 34 that secures the adapter element 26 to the freewheel device 10 upon rotation of the wheel W4. Due to rotation of the wheel W4, the adapter element 26 wants to move in a direction R relative to the second part 12 of the freewheel device 10. The 10 securing means 34 prevents the adapter element 26 from moving in said direction R but enhances the tightness of the adapter element 26 to the freewheel device 10.

In this embodiment of the adapter element 26, the securing means 34 comprise a flange 35 that extends from the cylindrical body 28 radially 15 outward, at least partly along the outer circumference of the body 28. In use, the flange 35 is thus pressed against the second part 12 of the freewheel device 10. The securing means 34 is positioned between the axle connector 14 and the second part 12 of the freewheel device 10, such that the flange 35 extends substantially parallel to an outer surface 36 of the second part 12 of the 20 freewheel device 10. In order to assemble the different parts of the freewheel arrangement 6, the adapter element 34 is provided in the second part 12 of the freewheel device from the outer surface 36 in direction R before connecting the first part 11 of the freewheel device 10 to the axle connector 14.

To assemble the driving assembly 1, the driving axle 2 is inserted in 25 the freewheel arrangements 6, 8 such that the respective drive bushes 3 are inserted in the respective receiving cavities 15 of the respective axle connectors 14. The respective ends 2a, 2b of the driving axle 2 extend subsequently through the axle connector 14, the freewheel device 10 and the wheel connector 16,18. Then the wheel W3, W4 (see Figs. 3a and 3b) is arranged to 30 the wheel bush 19 and the wheel W3, W4 is secured by providing a securing 10 element (not shown) to the respective end 2a, 2b of the driving axle 2 such that the wheel W3, W4 can not be removed from the wheel bush 19.

Referring to Figures 3a and 3b, driving of the vehicle V comprising 5 the driving assembly 1 according to the invention is explained. In Figure 3a, the vehicle V is driven in the driving direction D1 turning left and in Figure 3b, the vehicle V is driven in the driving direction D2 turning right. The vehicle V comprises a chassis with a main beam 40, front wheels Wl, W2, arranged on a front axle 42 and rear wheels W3, W4 arranged on the rear axle 10 2 via the respective left-hand freewheel arrangement 8 and the right-hand freewheel arrangement 6 according to the invention. The rear wheels W3, W4 are driven via the transmission means 4 (see Fig. 1) that in turn is driven via a chain that is running around it and which is driven by pedals.

When driving the vehicle V straight forward in the driving direction 15 D, the rear axle 2 rotates the axle connectors 14, that in turn rotate the freewheel device 10 in the rotational driving direction d and thus the rear wheels W3, W4. Consequently, both rear wheels W3, W4 are driven.

In case the vehicle V is steered to turn left (Fig. 3), the right rear wheel W4 has to travel a greater distance than the left rear wheel W3 in the 20 same time period. Consequently, the right rear wheel W4 will rotate faster than the left rear wheel W3. The inner part 12 of the right-hand freewheel arrangement 6 will rotate faster than the outer part 11, such that the right rear wheel W4 freewheels. The left rear wheel W3 is still driven.

In case the vehicle V is steered to turn right (Fig. 4), the left rear 25 wheel W3 has to travel a greater distance than the right rear wheel W4 in the same time period. Consequently, the left rear wheel W3 will rotate faster than the right rear wheel W4 such that the left rear wheel W3 freewheels and the right rear wheel W4 is driven. Thus, the vehicle V with the driving assembly 1 according to the invention can be driven by driving both rear wheels W3, W4 30 or by driving either one of the rear wheels W3, W4 allowing the other wheel 11 W3, W4 to freewheel, which enables performing stunts with the vehicle V or driving at rough terrain having an uneven ground surface.

The invention is not in any way limited to the exemplary 5 embodiments presented in the description and drawings. All combinations (of parts) of the embodiments shown and described are explicitly understood to fall within the scope of the invention. Moreover, many variations are possible within the scope of the invention, as outlined by the claims.

For instance, the adapter element 24 may have a different 10 construction as long as it provides the possibility to connect a left-handed outer thread of the wheel connector 16 to a right-handed inner thread of the freewheel device 10. Furthermore, the axle connector 14 and/or the wheel connectors 16, 18 may have different constructions. The wheel may be connected to the freewheel arrangement 6, 8 and/or to the driving axle 2 in a 15 different way. The driving axle 2 may be connected to the axle connector 14 in a different way. The vehicle V may be constructed such that the driving axle 2 is driven in a different way. Furthermore, the vehicle V may be different kinds of vehicles that may have two independently driven rear wheels W3, W4 that may freewheel when necessary.

20

However, other modifications, variations and alternatives are also possible. The specifications, drawings and examples are, accordingly, to be regarded in an illustrative rather than in a restrictive sense.

In the claims, any reference signs placed between parentheses shall 25 not be construed as limiting the claim. The word ‘comprising’ does not exclude the presence of other features or steps then those listed in a claim. Furthermore, the words ‘a’ and ‘an’ shall not be construed as limited to ‘only one’, but instead are used to mean ‘at least one’, and do not exclude a plurality. The mere fact that certain measures are recited in mutually different claims 12 does not indicate that a combination of these measures cannot be used to advantage.

Claims

A freewheel device (6) for a vehicle (V), such as a chain driven vehicle, for example a pedal go-kart, the device comprising a freewheel mechanism (10) with a first part (11) attached to a axle connection piece (14) adapted to receive a drive axle (2) and a second part (12) attached to a wheel connection piece (16) adapted to receive a wheel (W), the second part (12) of the freewheel mechanism (10) comprises a right-turning internal thread (20) adapted to receive an external thread (22) of the wheel connector (16), characterized in that between the second part (12) of the freewheel mechanism (10) ) and the wheel connecting piece (16) an adapter element (26) is provided which is arranged such that the freewheel device (6) can be used between the drive shaft (2) and a right wheel (W4) such that in use a connection between the freewheel mechanism (10) e n the wheel connector 15 (16) is maintained or strengthened by rotating the wheel connector of the right wheel (16) in a direction of travel (d), the adapter element (26) comprising a right-turning external thread (30) connected to the internal thread (20) of the second part (12) of the freewheel mechanism (10), the adapter element (26) comprising a left-turning internal thread (32) connected to a left-turning external thread (22) of the right-hand wheel connector (16) ).

2. Freewheel device according to claim 1, wherein the adapter element (26) comprises a locking means (34) for securing the adapter element (26) to the freewheel mechanism (10).

A freewheel device according to claim 2, wherein the locking means (34) comprises a flange that extends radially outwards at least partially along an outer periphery of an adapter element body (28). 5

A freewheel device according to any one of claims 2-3, wherein the locking means (34) is positioned between the drive shaft connector (14) and the second part (12) of the freewheel mechanism (10).

Freewheel device according to one of the preceding claims, wherein the adapter element (26) comprises a substantially cylindrical body (28).

Freewheel device according to one of the preceding claims, wherein a length of the adapter element (26) is substantially equal to a length of the internal thread (20) of the freewheel mechanism (10) viewed in a direction substantially parallel to a axis of rotation of the freewheel mechanism (10).

Freewheel device according to one of the preceding claims, wherein the freewheel mechanism (10) is a generally available freewheel mechanism with a right-turning internal thread (20), this being a freewheel mechanism (10) with a most common direction of rotation for threads. 25

A drive assembly (1) for a vehicle (V) such as a chain-driven vehicle, for example a pedal go-kart, the drive assembly (1) comprising a drive shaft (2) which is at a first right-hand end (2a) of the shaft (2) is provided with a freewheel device (6) according to one of the preceding claims and, viewed on a left-hand end (2b) in a direction of travel (D), is provided with a further freewheel device (8), wherein a wheel connecting piece (18) of the further freewheel device (8) is directly attached to a second part (12) of a freewheel mechanism (10) of the further freewheel device (8).

The drive assembly (1) of claim 8, wherein an outer diameter of a portion (24) of the right-hand wheel connector (16) of the right-hand freewheel device (6) facing the respective freewheel mechanism (10) is smaller than an outer one diameter of a portion of the left wheel connector (18) that faces the respective freewheel mechanism (10) of the left freewheel device (8).

10. Drive assembly (1) according to claim 8 or 9, wherein the drive shaft (2) comprises a transmission means (4) rotated in use by a drive element such as a chain connected to pedals such that at least one of the left-hand wheel connecting piece (18) and the right-hand wheel connector (16) is driven in a drive direction (d) via the respective freewheel device (8, 6).

11. Vehicle (V), such as a vehicle driven by means of a chain, for example a pedal go-kart, which preferably comprises a drive assembly (1) according to one of claims 8-10 and / or a freewheel device (6) according to one of claims 1-7.

12. Vehicle (V) as claimed in claim 11, wherein the vehicle comprises at least a left rear wheel and a right rear wheel, the respective rear wheels cooperating with a rear axle of the vehicle such that each rear wheel can be driven independently of the other and / or that both rear wheels can be driven simultaneously. 30

A vehicle according to claim 11, wherein the vehicle (V) comprises two front wheels (W1, W2) and two rear wheels (W3, W4), both of which are drivable, the respective wheels (W1, W2, W3, W4) being provided on a front axle (42) and a rear axle (2) respectively, wherein the 5 axes (42, 2) extend substantially parallel to each other.