WO2010123363A1

WO2010123363A1 - Transmission

Info

Publication number: WO2010123363A1
Application number: PCT/NL2010/050223
Authority: WO
Inventors: Teunis Karel Van Ee
Original assignee: Teunis Karel Van Ee
Priority date: 2009-04-23
Filing date: 2010-04-23
Publication date: 2010-10-28
Also published as: NL2002788C2; EP2422112A1

Abstract

Gear and gearbox having such a gear, comprising a first shaft (100) comprising a first (110) and a second drive wheel (130), a second shaft (200) comprising a first (210) and a second wheel (230) to be driven, wherein the first drive wheel and the second drive wheel, respectively, are coupled to the first wheel to be driven and the second wheel to be driven, respectively, wherein at least the second drive wheel is placed on the first shaft so as to be freely rotatable, and a gear change means that can be moved parallel to and over the first shaft so as to mesh with a drive wheel, wherein the first drive wheel is placed between the gear change means and the second drive wheel, and comprises an opening, wherein the gear change means is rotation-fixedly connected to a coupling means extending along the first shaft and adapted for engaging through the opening of the first drive wheel onto the adjacently situated second drive wheel, for a rotation-fixed coupling between the gear change means, the first drive wheel and the second drive wheel.

Description

TRANSMISSION

BACKGROUND OF THE INVENTION

The invention relates to a gear, particularly a gear for a vehicle having a pedal drive, more particularly a pedal car or go-cart, comprising a first shaft comprising a first and a second drive wheel, a second shaft comprising a first and a second wheel to be driven, wherein the first drive wheel is coupled to the first wheel to be driven and the second drive wheel is coupled to the second wheel to be driven, wherein at least the second drive wheel is placed on the first shaft so as to be freely rotatable, and a gear change means that can be moved parallel along and over the first shaft so as to mesh with one of the drive wheels.

Such a gear is known from DE 19807408 A1 , which describes a children's vehicle in which a first shaft is designed as a crankshaft. A second shaft is designed as a rear axle to which wheels are attached.

The crankshaft and the rear axle are coupled by two adjacently positioned chain transmissions between which can be switched by operating a gearstick. The crankshaft is provided with external straight teeth over which a hub, under the influence of a sideward displacement of the gearstick, can be axially shifted between two chain wheels placed on the crankshaft. Both outer ends of the hub are provided with cams that may mesh with recesses cooperating with the cams and positioned on the side surface of the chain wheels on the crankshaft. In a first position of the gearstick the crankshaft is coupled by a first chain transmission to the rear axle, wherein a second chain transmission is uncoupled. In a second position of the gearstick the crankshaft is coupled by the second chain transmission to the rear axle, wherein the first chain transmission is uncoupled.

With this gear a choice for a transmission is limited however to two transmissions.

It is an object of the present invention to provide an alternative gear wherein a choice can be made between at least two transmissions.

SUMMARY OF THE INVENTION

The invention provides a gear according to the opening paragraph, characterised in that at least the first wheel to be driven is placed on the second shaft via a freewheel coupling, and that the first drive wheel is placed between the gear change means and the second drive wheel, and comprises an opening, wherein the gear change means is rotation- fixedly connected to a coupling means extending along the first shaft and adapted for engaging through the opening of the first drive wheel onto the adjacently situated second drive wheel, for a rotation-fixed coupling between the gear change means, the first drive wheel and the second drive wheel.

This measure makes it possible to place two transmissions on the same side of the gear change means. On the one hand the gear change means can be rotation-fixedly coupled to the first drive wheel, that is provided with an opening onto which the coupling means can mesh, by moving the gear change means towards the first drive wheel until the coupling means meshes with the first drive wheel. On the other hand the gear change means can be rotation-fixedly coupled to the second drive wheel, that has also been provided with an opening with which the gear change means can mesh, by moving the gear change means further towards the second drive wheel until the coupling means meshes with the second drive wheel.

As the first and/or second wheel to be driven is placed on the second shaft via a freewheel coupling, it is possible to let the drive means come to a temporary standstill and keep it that way, whereas means to be driven brought into motion, such as for instance a vehicle, can remain in motion.

The gear change means can be rotation-fixedly coupled to the second drive wheel via the coupling means, as the coupling means extends through the first drive wheel, particularly through a through-opening in the side surface of the first drive wheel. As the coupling means extends through the opening of the first drive wheel and thus engages onto the first drive wheel, in case of rotation-fixedly coupling the second drive wheel, the first drive wheel is also rotation-fixedly coupled to the gear change means. This measure offers the possibility to design the gear in a compact manner, as the first drive wheel can be placed substantially directly adjacent to the second drive wheel.

In one embodiment a first transmission ratio of a first transmission between the first drive wheel and the first wheel to be driven is smaller than a second transmission ratio of a second transmission between the second drive wheel and the second wheel to be driven. When the first drive wheel is rotation-fixedly coupled to the drive means by the gear change means via the coupling means and the second drive wheel is not, the drive means are able to drive the means to be driven via the first transmission. When both the first and the second drive wheel are rotation-fixedly coupled to the drive means by the gear change means via the coupling means, and at least the first wheel to be driven is placed on the second shaft via a freewheel coupling, the drive means are able to drive the drive means to be driven via the second transmission. As the second wheel to be driven rotates at a higher speed than the first wheel to be driven rotates, the first wheel to be driven will run freely and not contribute to the drive.

In one embodiment adjacent to the second drive wheel at a side facing away from the first drive wheel, one or more further drive wheels are placed on the first shaft so as to be freely rotatable and which have each been coupled to one or more further wheels to be driven placed on the second shaft for forming a series of adjacently placed transmissions. In that way a gear is provided in which a choice is given between three or more transmissions positioned adjacent to each other in a structure. In one embodiment the second and/or the further drive wheels comprises and/or comprise an opening through which the coupling means can engage onto the second and/or the further drive wheels for a rotation-fixed coupling between the gear change means and one or more of the drive wheels. In that way, analogous to rotation-fixedly coupling the second drive wheel, the gear change means can be rotation-fixedly coupled to the third drive wheel, that has also been provided with an opening with which the coupling means can mesh, by moving the gear change means further towards the third drive wheel until the coupling means meshes with the third drive wheel. In the same way the gear change means can be rotation-fixedly coupled to further drive wheels, that have also been provided with an opening with which the coupling means can mesh, by moving the gear change means further towards the further drive wheels until the coupling means meshes with the further drive wheels.

In one embodiment considered from the gear change means the transmission ratios of the adjacently placed transmissions increase. When both the first and the second and the third drive wheel are rotation-fixedly coupled to the drive means by the gear change means via the coupling means, and at least the first and the second wheel to be driven are placed on the second shaft by means of a freewheel coupling, the drive means are able to drive the means to be driven via the third transmission. As the third wheel to be driven rotates at a higher speed than the first and second wheels to be driven rotate, the freewheel couplings with which the first and second wheels to be driven are placed on the second shaft will run free and therefore transfer no torque. When, considered generically, a number of drive wheels is rotation-fixedly coupled to the drive means by the gear change means via the coupling means, the drive means are able to drive the means to be driven via the transmission having the largest transmission ratio, of which the rotation-fixedly coupled drive wheel preferably is situated farthest from the gear change means. As the wheel to be driven rotates at a higher speed than the wheels to be driven of the transmissions of which the drive wheel is situated between the gear change means and the rotation-fixedly coupled drive wheel situated farthest from the gear change means rotate, the wheels to be driven of a transmission having a smaller transmission ratio will run free and transfer no torque.

In one embodiment the coupling means comprise at least one first finger that extends substantially parallel to the first shaft towards the drive wheels, wherein the finger is adapted for extending through the openings of the drive wheels, wherein the dimensions of the finger are smaller than or equal to the dimensions of the openings. The finger or fingers are active as coupling means with which the drive wheels can be consecutively strung together wherein the strung drive wheels are all rotation-fixedly coupled, via the gear change means, with drive means. For insertion and meshing of the finger with openings provided in the drive wheels, it is necessary that the fingers pass through the openings in the drive wheels.

In one embodiment the finger tapers in a direction of the drive wheels. By having the fingers taper in a direction facing away from the gear change means a smooth coupling of drive wheels onto the coupling means and/or the gear change means is achieved.

In one embodiment the gear change means comprises an engagement part on which an operating means can engage for moving the gear change means substantially parallel to and/or over the first shaft. By providing the gear change means with an engagement part it is possible to let an operating means engage thereon to move the gear change means over the first shaft in a direction of the drive wheels wherein the coupling means rotation-fixedly couples the drive wheels to the gear change means.

In one embodiment the engagement part is formed substantially rotation symmetrical with respect to the first shaft. In that way the operating means is able to assume a certain momentary position whereas the engagement part rotates around a shaft that is substantially parallel to the longitudinal direction of the first shaft. From this momentary position under the influence of a movement of the operating means a movement of the gear change means can be achieved, wherein the gear change means may or may not rotate around a shaft that is substantially parallel to the longitudinal direction of the first shaft.

In one embodiment the operating means comprises a slipper for engaging onto the engagement part of the gear change means. By operating the operating means, the gear change means can be moved in a direction of the drive wheels over a desired distance over the first shaft by bringing the slipper in abutment with the engagement part of the gear change means and moving the gear change means. By providing the operating means with a slipper that engages onto the engagement part of the gear change means a smooth movement becomes possible between the operating means and the engagement means, wherein braking the drive is minimal. Moreover less wear will occur as a result between the operating means and the engagement means. The braking and wear can be minimised even further by choice of material, for instance when a material with a lubricating action or a low friction coefficient is selected, preferably a Teflon-like material.

In one embodiment the operating means comprises a holder for the slipper, wherein the holder is rotatably positioned about an operating axle extending substantially transverse to a direction of movement of the gear change means. In that way it become possible to rotate a holder, connected to a handle placed outside of the gear, and containing the slipper, around an operating axle wherein the slipper is subjected to a movement having a component in the direction of movement of the gear change means. The gear change means may as a result be moved in a desired direction over a desired distance.

In one embodiment the operating means comprises a holder on which the slipper is rotatably positioned about a hinge pin extending substantially transverse to a direction of movement of the gear change means. In that way slippers that are not round can also be used, such as for instance elongated ones.

In another embodiment the gear change means when the coupling means meshes with the second drive wheel, is only rotation-fixedly coupled to the second drive wheel. In case of a rotation-fixed coupling of the first drive wheel the drive means drive the means to be driven, such as for instance a vehicle, via the first drive wheel, wherein the second drive wheel is not rotation-fixedly coupled. By moving the gear change means such that the second drive wheel is rotation-fixedly coupled to the gear change means via the coupling means, and wherein the first drive wheel is not rotation-fixedly coupled, a gear is provided wherein a choice is given between two transmissions. The means to be driven are driven by the drive means via the transmission that either comprises the first drive wheel and the first wheel to be driven, or comprises the second drive wheel and the second wheel to be driven.

In one embodiment the coupling means at an outer end facing the drive wheels is provided with radially extending teeth. In one embodiment the drive wheels comprise recesses for receiving the radially extending teeth of the coupling means. By providing the drive wheels with recesses that are suitable for receiving the radially extending teeth of the coupling means a form-closed coupling can be achieved with which a torque from the coupling means can be transferred to the drive wheel.

In one embodiment the first drive wheel is placed on the second drive wheel so as to be rotatable. In that way it becomes possible on the one hand to rotation-fixedly couple the coupling means to the first drive wheel without the second drive wheel being rotation-fixedly coupled.

On the other hand it becomes possible to rotation-fixedly couple the coupling means to the second drive wheel without the first drive wheel being rotation-fixedly coupled.

In one embodiment the gear change means and the coupling means are integrally formed. As a result a part can be obtained that is easy to produce at low cost wherein two functions can be combined in one part. First of all the function of changing gear wherein the gear change means can be moved parallel to and/or over the first shaft. Second of all the function of rotation-fixedly coupling one or more drive wheels placed on the first shaft.

In one embodiment the gear change means on either side is provided with coupling means adapted for engaging through the opening of a drive wheel onto the adjacently situated second drive wheel, for a rotation-fixed coupling between the gear change means and a drive wheel. In that way it becomes possible to provide one or more transmissions that are placed adjacent to the gear change means at a first side of the gear change means and at a second side of the gear change means that faces away from the first side of the gear change means. The transmissions may for instance be adapted such that transmissions corresponding with a forward drive of a vehicle are placed at the first side of the gear change means and that for instance transmissions corresponding with a rearward drive of a vehicle are placed at the second side of the gear means. On the other hand the transmissions may for instance be adapted such that the transmissions corresponding with a forward drive of a vehicle are placed at the first side of the gear change means and that for instance the transmissions that have a fixed coupling to the first shaft and second shaft are placed at the second side of the gear change means, which transmissions are suitable for driving a vehicle in a forward or a rearward motion of a vehicle in case of a drive of the drive means in a direction corresponding with a forward or rearward drive, respectively.

In one embodiment the first drive wheels are coupled to the second drive wheels by means of transmission belts. In that way a gear is provided wherein in an alternative way the drive means drive the means to be driven, such as for instance a vehicle.

In one embodiment the drive wheels are designed like gear wheels and the transmission belts are designed like geared belts. In that way a gear is provided wherein in an alternative way the drive means drive the means to be driven, such as for instance a vehicle. Toothed transmission belts are particularly suitable for transferring relatively larger torques and capacities in comparison with the transmission belts that have no teeth. In case of transmissions with toothed transmission belts there is no slippage in the transfer of torque between a toothed drive wheel and a toothed transmission belt, which may indeed occur in case of transmission belts without teeth.

In one embodiment the drive wheels are designed like chain wheels and the transmission belts are designed like chains. In that way a gear is provided wherein in an alternative way the drive means drive the means to be driven, such as for instance a vehicle. Chain transmissions are particularly suitable for transferring relatively large torques and capacities, wherein the chains can be loaded with a large tensile force. Also in case of chain transmissions slippage will not occur in the transfer of torque between a chain wheel and a chain. Moreover when using chains and chain wheels use can be made of regular bicycle parts.

In one embodiment the first drive wheels and the first wheels to be driven comprise meshing gear wheels, and further drive wheels and further wheels to be driven comprise meshing gear wheels, preferably with one or more connecting gear wheels placed between the first drive wheels and the first wheels to be driven, the further drive wheels and the further wheels to be driven, respectively. By using gear wheels the gear can be designed in a highly compact manner and the gear can be used in for instance vehicles wherein large torques and capacities have to be transferred.

In one embodiment a brake member is placed near the second drive wheel, which brake member when activated brakes the second drive wheel. This is particularly advantageous for an embodiment wherein the gear change means, when the coupling means meshes with the second drive wheel, is rotation-fixedly coupled to both the first and the second drive wheel. By at least during moving the coupling means towards the second drive wheel, activating the brake member, the second drive wheel is braked, as a result of which a rotation speed of the second drive wheel is lowered. As a result the coupling means can be coupled to the second drive wheel more easily and with more accuracy.

In one embodiment the brake member extends substantially around the first shaft and is placed at a side of the second drive wheel that faces away from the first drive wheel. During moving the coupling means towards the second drive wheel the second drive wheel will usually have a different rotation speed than the coupling means. Therefore there is a risk that the coupling means does not immediately couple with the second drive wheel. In that case the coupling means will push against the second drive wheel in the direction of the brake member. As a result the brake member can be activated to brake the rotation speed of at least the second drive wheel. On the one hand the drive wheels can be manufactured such that they show some degree of flexibility, as a result of which when the coupling means pushes against the drive wheel, said drive wheel is bent into the direction of the brake member, as a result of which the brake member is activated. On the other hand the drive wheels can be placed on the first shaft with some clearance, as a result of which when the coupling means pushes against the drive wheel, said drive wheel will shift in the direction of the brake member, thus activating the brake member.

In one embodiment the brake member is rotation-fixedly connected to a part of the gear placed adjacent to the side of the second drive wheel that faces away from the first drive wheel and the brake member comprises a brake surface that faces the second drive wheel. As the brake member is rotation-fixedly connected to the said part of the gear, a difference in rotation speed between the second drive wheel and the said part is reduced when activating the brake member.

In one embodiment the part of the gear placed adjacent to the side of the second drive wheel that faces away from the first drive wheel, comprises a part of the housing of the gear. As a result the brake member is rotation-fixedly connected to the housing and when activating the brake member the rotation speed of the second drive wheel with respect to the housing will be reduced.

In a further embodiment the part of the gear placed adjacent to the side of the second drive wheel that faces away from the first drive wheel, comprises a further drive wheel. The brake member is now rotation- fixedly connected to the further drive wheel and will when the brake member is activated reduce the difference in rotation speed between the second drive wheel and the further drive wheel. Preferably said further embodiment comprises a further brake member adjacent to a side of the further drive wheel that faces away from the second drive wheel. Said further brake member is also rotation-fixedly connected to a part of the gear placed adjacent to the side of the further drive wheel that faces away from the second drive wheel. In a further embodiment the gear comprises a series of further drive wheels that are placed on the first shaft adjacent to the side of the second drive wheel that faces away from the first drive wheel, wherein between each one of these further drive wheels a brake member is placed, wherein a last brake member is placed between a last drive wheel of the series of further drive wheels and the housing, and wherein the last brake member is rotation-fixedly connected to the housing. With the last drive wheel is meant the drive wheel of the series of further drive wheels that is placed on the first shaft at the largest distance from the second drive wheel. During moving the coupling means towards the second drive wheel, the second drive wheel and also the drive wheels of the series of further drive wheels, will usually have another rotation speed than the coupling means. Therefore there is a risk that the coupling means does not immediately couple with the second drive wheel. In that case the coupling means will push against the second drive wheel in the direction of the brake member. By pushing against the second drive wheel all brake members between the various drive wheels are activated to reduce the rotation speed of the whole series with respect to the housing.

In an alternative embodiment the brake member is rotation-fixedly connected to the second drive wheel and the brake member comprises a brake surface that faces a part of the gear placed adjacent to the side of the second drive wheel that faces away from the first drive wheel. By this mechanic reversal of the principle as stated in the embodiments mentioned above, the same result can be achieved.

In one embodiment the brake surface extends substantially transverse to the first shaft. In one embodiment the brake surface is placed near a side surface of the second drive wheel facing the brake member or the part of the gear.

In one embodiment the brake member is at least partially made of synthetic material. Preferably the brake member is manufactured of an injection moulded synthetic material.

In one embodiment the brake member comprises a through-opening for passing the coupling means through. According to a second aspect the invention provides a gearbox that can be placed between a drive and wheels to be driven, wherein the gearbox comprises a gear that may have one of the preceding embodiments. In that way a gearbox is provided comprising a gear according to the invention wherein a choice is provided between two or more transmissions and that can be placed as one unity between the drive and the wheels to be driven.

In one embodiment the drive comprises a pedal drive. This embodiment intends the gearbox to be built in or built up in or on a vehicle, such as a children's vehicle, children's bike or pedal car.

In one embodiment the gear is accommodated in a housing that is provided with a first through-opening for a coupling of the drive or drive means to the first shaft. In one embodiment the gear is accommodated in a housing that is provided with a second through-opening for a coupling of the wheels or means to be driven to the second shaft. By accommodating the gear in a housing parts, especially rotating parts of the gear, are protected against the scouring effect of for instance sand and/or against the corroding effect of for instance mud and/or water. For a coupling of the first shaft to the drive means and the second shaft to the means to be driven, the housing is provided with the first and second through-opening, respectively. As via the first and the second through-openings sand and/or mud and/or water may also end up within the housing, the transmission between the drive means and the first shaft, and the transmission between the means to be driven and the second shaft, respectively, can also be accommodated in a housing. In case of said transmissions being provided by chains, the chain casings can function as housing.

In one embodiment of the gearbox the gear is accommodated in a housing provided with a guiding device adapted for guiding a chain during its insertion when mounting the chain around a chain wheel of the gear. In one embodiment the guiding device comprises an edge that is spaced apart from at least a part of the circumference of the chain wheel on which the chain is mounted. In one embodiment the edge has a thickness extending between opposed inner links of a chain. In one embodiment the edge has a thickness that substantially equals a thickness of the teeth of a chain wheel. These measures each provide a possibility, even when the gearbox has been mounted on a vehicle, wherein the housing is closed, to couple the drive means and/or the means to be driven via a chain to a gear in the gearbox, by placing an outer end of the chain around a chain wheel, wherein the outer end of the chain can be guided by the guiding device to a location in the gearbox from where the outer end of the chain can be picked up.

According to a third aspect the invention provides a children's vehicle, particularly a pedal car, having a drive for driving the wheels to be driven, wherein the children's vehicle is provided with a gearbox placed between the drive and the wheels to be driven, wherein the gearbox comprises a gear that may have one of the embodiments mentioned above.

The aspects and measures described in this description and the claims of the application and/or shown in the drawings of this application may where possible also be used individually. Said individual aspects may be the subject of divisional patent applications relating thereto. This particularly applies to the measures and aspects that are described per se in the sub claims.

SHORT DESCRIPTION OF THE DRAWINGS

The invention will be elucidated on the basis of a number of exemplary embodiments shown in the attached drawings, in which:

Figure 1 shows a view in perspective of a gear according to the invention wherein an upper half of the housing has been removed;

Figure 2 shows a cross-section of the gear according to figure 1 ;

Figure 3 shows a view in perspective of a disassembled assembly comprising two chain wheels and a gear change means with a coupling means connected thereto that is able to mesh with one of the two chain wheels; Figure 4A shows a view in perspective of a gear change means with a coupling means connected thereto;

Figure 4B shows a side view of a number of chain wheels coupled by the coupling means of figure 4A;

Figure 5 shows a mechanism for moving the gear change means according to figure 3 or 4A;

Figure 6 shows a view in perspective of the open housing with guiding device for during mounting guiding an outer end of a chain;

Figure 7A shows a top view of a part of a gear according to a second embodiment;

Figure 7B shows a cross-section of the gear according to figure 7A;

Figure 8 shows a detail of the cross-section of figure 7B; and

Figures 9 and 10 show a detail of a cross-section of a gear with an alternatively-shaped brake member, respectively.

DETAILED DESCRIPTION OF THE DRAWINGS

Figure 1 shows a gear designed like a gearbox 1 having a lower half of a housing 2 in which a first shaft 100 is positioned parallel to a second shaft 200, on which chain wheels are placed for forming several chain transmissions between the first shaft 100 and the second shaft 200.

Near the first shaft 100 a front side 21 of the housing 2 has been provided with a first through-opening 22. Through said opening 22 a drive chain {not shown) placed at least partially outside of the gear 1 can be passed, which can be driven by a chain wheel placed outside of the gear 1 which chain wheel is for instance coupled to pedals (not shown) or to a motor, for instance an electromotor.

Near the second shaft 200 a rear side 23 of the housing 2 is provided with a second through-opening 24. Through said opening 24 a chain to be driven {not shown) placed at least partially outside of the gear 1 can be passed, for driving a chain wheel placed outside of the gear 1 which wheel is for instance coupled to wheels to be driven (not shown) of a vehicle.

Substantially halfway the length of the first shaft 100 a first chain wheel 1 10 is placed thereon. The first chain wheel 1 10 is coupled to a drive means, such as a drive chain (not shown) placed at least partially outside of the gearbox, which drive chain rotation-fixedly couples the first chain wheel 1 10 to the pedals of a go-cart or pedal car. The first shaft 100 is coupled to the housing 2 near a first outer end and a second outer end facing away from the first outer end via a first bearing 101 and a second bearing 102, respectively, wherein the first shaft 100 is able to rotate about a centre line 103.

Between the first bearing 101 and the first chain wheel 110, near the first bearing 101 a second chain wheel 130 is fixedly placed on the first shaft 100.

Between the first chain wheel 1 10 and the second chain wheel 130 a gear change means is placed on the first shaft 100, which gear change means has the design of a first hub 3 that can be moved over the first shaft 100 in the longitudinal direction V of the first shaft 100 by operating a mechanism 4 of which an operating axle 41 extends substantially transverse to the longitudinal direction V of the first shaft 100.

Between the first chain wheel 1 10 and the second bearing 102 a first set 120 of chain wheels is placed on the first shaft 100, so as to be substantially freely rotatable. In this example the first set 120 of chain wheels comprises a third, fourth, fifth and sixth chain wheel 122, 123, 124, 125, which in this order, are placed adjacent to each other on the first shaft 100 between the first chain wheel 1 10 and the second bearing 102. In this case the third chain wheel 122 is active as "first drive wheel", the fourth chain wheel 123 is active as "second drive wheel", and the fifth and sixth chain wheel are active as "further drive wheels", as mentioned in the claims. Near a first outer end and a second outer end facing away from the first outer end, the second shaft 200 is coupled to the housing 2 via a third bearing 201 and a fourth bearing 202, respectively, wherein the second shaft 200 is able to rotate about an axis of rotation 203 that substantially coincides with a centre line that extends parallel to a longitudinal direction W of the second shaft 200.

On the second shaft 200 a seventh chain wheel 210 and an eighth chain wheel 21 1 are placed close to each other. The seventh and eighth chain wheel 210 and 21 1 have each been adapted to be coupled to the means to be driven such as a driven shaft of a go-cart connected to the wheels, each via a chain (not shown) placed at least partially outside of the gearbox 1.

Between the eight chain wheel 21 1 and the first bearing 201 in this example near the first bearing 201 a ninth chain wheel 230 is placed for forming a chain transmission (not shown) with the second chain wheel 130 that is placed on the first shaft 100 near the first bearing 101.

Between the eight chain wheel 21 1 and the ninth chain wheel 230 a second gear change means is placed on the second shaft 200, which gear change means is designed like a second hub 5 which can be moved over the second shaft 200 in the longitudinal direction W of the second shaft 200 by operating a mechanism 6 of which an operating axle 61 extends substantially transverse to the longitudinal direction W of the second shaft 200.

Between the seventh chain wheel 210 and the fourth bearing 202 a second set 220 of various chain wheels is placed for forming a series of adjacently situated chain transmissions with the first set 120 of chain wheels that is placed on the first shaft 100. In this example the second set 220 of chain wheels comprises a tenth, eleventh, twelfth and thirteenth chain wheel 222, 223, 224, 225, which in that order, are placed adjacent to each other on the second shaft 200 between the seventh chain wheel 210 and the fourth bearing 202. The chain wheels of the second set 220 have been provided with a clearance that only transfers a torque for a forward drive to the second shaft 200. In this case the tenth chain wheel 222 is active as "first wheel to be driven", the eleventh chain wheel 223 is active as "second wheel to be driven", and the twelfth and thirteenth chain wheel are active as "further wheels to be driven", as mentioned in the claims.

Figure 2 shows a lower half of the gearbox 1 according to the invention, by means of a cross-section in plane containing the centre lines 103, 104 of the first shaft 100 and the second shaft 200. On the first shaft 100 the first hub 3 is placed that is active as gear change means and may for instance by means of a key-key way connection (not shown) be rotation-fixedly coupled to the first shaft 100. In another embodiment the first shaft 100 may be rotation-fixedly positioned in the housing, wherein both chain wheels and the first hub 3 are positioned around the first shaft 100 so as to be rotatable.

As figure 4A shows, the first hub 3 at one end is provided with a raised edge 31 which forms a first shoulder of the first hub 3. Two first pins

34 and 35 of the first hub 3 extend like fingers transverse to the first shoulder 31 in a direction substantially parallel to the direction of movement V and facing the second bearing 102. The first pins 34 and

35 function as coupling means for coupling the first hub 3 to one or more of the first, third, fourth, fifth and sixth chain wheels 1 10, 122, 123, 124, 125. The first pins 34 and 35, that may further also be referred to as fingers 34 and 35, are placed at the outside of the first shaft 100 and extend substantially parallel to the first shaft 100. In this example as shown in figure 2, the fingers 34 and 35 are spaced apart from the first shaft 100 so that they can be placed in the through- openings 1 1 1 , 1 12, 1 13, 1 14, 1 15 in the side surfaces of the first, third, fourth, fifth and sixth chain wheels 1 10, 122, 123, 124, 125.

Near an end facing away from the first shoulder 31 , the first hub 3 comprises a second raised edge 32 forming a second shoulder 32 of the first hub 3. In a space 33 extending around the first hub 3 and between the first shoulder 31 and the second shoulder 32 a block 42 (shown in figure 1) of the operating mechanism 4 is able to engage wherein the block 42 is adapted for moving the first hub 3 axially over the first shaft 100, in the direction V. In this example the block 42 is designed like a slipper which is positioned in the space 33 between the first and second shoulder 31 and 32 of the first hub 3. The surfaces of the shoulders 31 and 32 facing the space 33 at least partially abut the slipper 42, with minimum clearance. When rotating the first hub 3 the surfaces of the shoulders 31 and 32 facing the space 33 slide over side surfaces of the slipper 42.

Figure 5 shows an operating mechanism 4 comprising a swivel axle 41 , a holder 43 and a first and second axis of rotation 45, 46 around which the slipper 42 can be rotatably positioned. Due to rotation of a holder 43 coupled to the swivel axle 41 , a side surface of the slipper 42 is brought to abut a surface of the first shoulder 31 or the second shoulder 32 that faces the space 33, for in case of further rotation of the holder 43 moving the first hub 3. In another embodiment a mechanism can be used wherein the first hub 3 can be moved over the first shaft 100 under the influence of a translation of an alternative holder and/or an alternative slipper.

The first chain wheel 1 10 that can be driven by means of drive means, such as for instance the drive chain (not shown), is rotation-fixedly coupled to the hub 3 because outer ends 36 and 37 of the first pins 34 and 35 mesh with through-openings 1 1 1 and 191 in the first chain wheel 1 10, that are also shown in figure 4B.

In this example the first hub 3 has two second pins 38 and 39 that extend transverse to the second shoulder 32 in a direction substantially parallel to the direction of movement V, however facing the first bearing 101. Figure 2 shows the gear 1 in the situation in which the second chain wheel 130 is rotation-fixedly coupled to the hub 3 because the second pins 38 and 39 mesh with through-openings 131 and 132 in the second chain wheel 130. In the situation shown the gear 1 is in a first mode for a drive of the means to be driven in at least a rearward direction.

The gear 1 can be brought into a second mode for driving the means to be driven in a forward direction by operating a mechanism 4, wherein the first hub 3 is moved in the direction V towards the second bearing 102. The outer ends 38 and 39 are retracted from the through- openings 131 and 132 of the second chain wheel 130, after which in this example the second chain wheel 130 is situated rotation free on the first shaft 100, for instance on the first shaft 100 bearing mounted by a rolling bearing or slide bearing. The outer ends 36 and 37 of the pins 34 and 35 of the first hub 3 that are inserted through the first chain wheel 1 10, may at least extend to a third chain wheel 122 that is provided with through-openings 1 12 and 192, as is also shown in figure 4B. In this example the third chain wheel 122 is placed rotation free on the first shaft 100, for instance bearing mounted by a rolling bearing or slide bearing. When for instance due to rotation of the third chain wheel with respect to the first shaft 100, the outer ends 36 and 37 of the pins 34 and 35 position themselves in front of the through- openings 1 12 and 192, under the influence of a first hub 3 moving towards the second baring 102 the outer ends 36 and 37 can get into the through-openings 1 12 and 192, for rotation-f ixedly coupling the third chain wheel 122, the first chain wheel 1 10 and the first hub 3.

In the same way the fourth, the fifth and the sixth chain wheel 123, 124, 125, placed rotation free on the first shaft 100 and for instance bearing mounted by a rolling bearing or a slide bearing, can be rotation- fixedly coupled with the first hub 3 by moving the first hub 3 further in the direction of the second bearing 102. For rotation-fixed coupling the fourth, fifth and sixth chain wheel 123, 124, 125 are provided with through-openings 1 13 and 193, and 1 14 and 194, respectively, and

1 15 and 195, respectively, as is also shown in figure 4B.

When moving the first hub 3 in a direction of the third, fourth, fifth and/or sixth chain wheel 122, 123, 124, 125 the outer ends 36 and 37 of the first hub 3 have a piloting function for insertion in and through the openings 112, 113, 1 14, 1 15 of said chain wheels. For letting the insertion of the outer ends 36 and 37 of the first hub 3 run smoothly, the pins 34 and 35 preferably taper as shown in figure 4A. The pins 34 and 35 that taper to the first shoulder 31 also let the retraction of the pins 34 and 35 of the first hub 3 from the third, fourth, fifth and/or sixth chain wheel 122, 123, 124, 125 run smoothly, wherein the tapering shape prevents that the chain wheels remain stuck on the pins 34 and 35. For a forward drive of the means to be driven a torque from the first chain wheel 1 10 can be transferred to the second shaft 200 via one of the four adjacently positioned chains (not shown) that couple the third, fourth, fifth and sixth chain wheel 122, 123, 124, 125 to the tenth, eleventh, twelfth and thirteenth chain wheel 222, 223, 224, 225, respectively. For an exclusively forward drive of the means to be driven the tenth, eleventh, twelfth and thirteenth chain wheel 222, 223, 224, 225 are coupled to the second shaft 200 via a freewheel coupling {not shown). The freewheel couplings are placed such on the second shaft 200 that under influence of a drive of the drive means corresponding with a forward drive of the means to be driven of a vehicle, a torque can be transferred to the second shaft 200 in a direction corresponding with the forward drive of the means to be driven. When the drive means are driven corresponding with a rearward drive, no torque is transferred.

The adjacently positioned chain transmissions have an increasing transmission ratio considered from the chain transmission comprising the third and the tenth chain wheel 122 and 222. In this example the third, fourth, fifth and sixth chain wheel 122, 123, 124, 125 in this order have a larger number of teeth and/or a larger diameter, whereas the tenth, eleventh, twelfth and thirteenth chain wheel 222, 223, 224, 225 all have the same number of the teeth and/or the same diameter. When the sixth chain wheel 125 is rotation-f ixedly coupled to the first shaft 100, wherein implicitly also the third, fourth and fifth chain wheel 122, 123, 124 are rotation-fixedly coupled, the speed of the chain coupling the sixth chain wheel 125 to the thirteenth chain wheel 225, is largest of all transmissions. As in this situation the twelfth, eleventh and tenth chain wheel 224, 223, 222 in this order rotate at a slower speed of revolution, the twelfth, eleventh and tenth chain wheel 224, 223, 222 can run free and thus they will not contribute to the transfer of a torque to the second shaft 200. The chain wheels that rotate more slowly are thus able to rotate freely with respect to the second shaft 200 that rotates faster, wherein a chain wheel of which the speed of revolution is just as large as the one of the second shaft 200, transfers the torque. A chain wheel on the second shaft 200 that is part of a chain transmission having a largest transmission ratio, in this example the thirteenth chain wheel 225, can be permanently rotation-fixedly connected to the second shaft 200. However, in case the sixth chain wheel 125 is rotation-fixedly coupled to the first shaft 100 by the first hub 3, wherein the gear of the gearbox 1 a is placed on a vehicle that for instance drives down an incline, the means to be driven, such as for instance the wheels, are able to drive the drive means, such as for instance pedals, via the gear. That is why the thirteenth chain wheel 225 shown in this example, is placed on the second shaft 200 via a freewheel coupling (not shown}, so that the second shaft 200 is able to rotate freely with respect to for instance a substantially motionless chain wheel 225.

Figure 2 further shows a gear of the gearbox 1 according to the invention, wherein the second chain wheel 130 and the ninth chain wheel 230 can be coupled via a chain (not shown) for a rearward drive of the means to be driven of. for instance a vehicle. Via said chain transmission a torque can be transferred via the first shaft 100 onto the second shaft 200, wherein the ninth chain wheel 230 via a freewheel coupling (not shown) is rotation-fixedly coupled in one rotation direction to the second shaft 200. The freewheel coupling is placed such on the second shaft 200 that under the influence of a drive of the drive means the means to be driven are driven in a direction corresponding with the rearward drive of for instance a vehicle.

In another example the ninth chain wheel 230 can however also be permanently rotation-fixedly coupled in both rotation directions to the second shaft 200, for instance by means of a keyed connection. In that way it becomes possible to transfer a torque in two directions via the first shaft 100 onto the second shaft 200 via a chain that couples the second chain wheel 130 to the ninth chain wheel 230. In that case the drive means are directly rotation-fixedly coupled to the means to be driven with which for instance forward and rearward manoeuvring is possible for accurately positioning a vehicle provided with the gearbox 1. On the second shaft 200 a second hub 5 is placed, which for instance by means of a key-key way connection 50 is rotation-fixedly coupled to the second shaft 200. The second hub 5 is adapted for providing a choice in a rotation-fixed coupling of the second shaft 200 to either the seventh chain wheel 210, or the eighth chain wheel 21 1. The second hub 5 can bring the gear 1 in a first situation, wherein the seventh chain wheel 210 is rotation-fixedly coupled to the second shaft 200 and the eighth chain wheel 21 1 is rotation free. The gear 1 can be brought in a second situation, wherein the eighth chain wheel 21 1 is rotation-fixedly coupled to the second shaft 200 and the seventh chain wheel 210 is rotation free. The gear 1 can be brought in the first and/or second situation by operating a mechanism 6 of which an operating axle 61 extends substantially transverse to the longitudinal direction W of the second shaft 200.

Figure 3 shows that the second hub 5 in this example at a first outer end 58 is provided with two adjacently formed raised edges 51 and 52 which form a third shoulder 51 and a fourth shoulder 52 of the second hub 5. In a space 53 extending around the second hub 5 and between the third shoulder 51 and the fourth shoulder 52 a block 62 (shown in figure 1 ) can engage onto the third shoulder 51 and the fourth shoulder 52 for being able to move the second hub 5 axially over the second shaft 200 in a direction W.

In this example a cylindrical portion 54 extends from the third shoulder 51 of the second hub 5 in a direction substantially parallel to the direction of movement W and facing the fourth bearing 202. At a second end 59, that faces away from the first end 58 of the hub, the cylindrical portion 54 is provided with a number of projecting parts of which figure 2 shows a first projecting portion 55 and a second projecting portion 56. The first and second projecting portions 55 and 56 function as coupling means for coupling the second hub 5, that is rotation-fixedly coupled to the second shaft 200, to the seventh or eighth chain wheel 210, 211 and may furthermore also be referred to as teeth 55 and 56.

Figure 2 shows a situation wherein at least a first and second tooth 55 and 56 of the second hub 5 mesh with an inner work 212 of the eighth chain wheel 21 1 , which eighth chain wheel 211 is placed rotation free on an external work 208 of the seventh chain wheel 210 via a radial bearing 217. The inner work 212 of the eight chain wheel 211 comprises at least cavities (not shown) corresponding with the first and second tooth 55 and 56, with which, in the situation shown, at least the first and the second tooth 55 and 56 of the second hub 5 mesh. By bringing at least the first and second tooth 55 and 56 into the corresponding cavities, the eighth chain wheel 21 1 is form-closed and rotation-fixedly coupled to the second shaft 200.

Thus via a rotation-fixed coupling between the second hub 5 and the second shaft 200 a torque from the second shaft 200 can be transferred to the eighth chain wheel 21 1 which via a chain to be driven can be coupled to means for be driven of for instance a vehicle. In that case it does not matter by which chain transmission a torque is transferred via the first shaft 100 onto the second shaft 200.

Figure 2 shows a situation in which the seventh chain wheel 210 is placed rotation free on the second shaft 200, in this example by two adjacently positioned radial bearings 218 and 219. The seventh chain wheel 210 is adapted for being rotation-fixedly coupled as soon as the eighth chain wheel 21 1 is rotation free from the second shaft 200. The rotation-fixedly coupled eighth chain wheel 21 1 shown in figure 2, can become rotation free by sufficiently moving the second hub 5 in the direction of the seventh chain wheel 210 over the second shaft 200 in a longitudinal direction W of the second shaft 200.

Figure 5 shows a swivel axle 61 , a holder 63 and a first and second axis of rotation 65, 66 around which the block 62 can be rotatably positioned. Due to rotation of a holder 63 coupled to the swivel axle 61 the block 62 urges the second hub 5 to move wherein at least the first and second tooth 55 and 56 of the second hub 5 become detached from the cavities in the inner work 212 of the eighth chain wheel 21 1 which cavities are at least corresponding with the first and second tooth 55 and 56. In another embodiment a mechanism can be used wherein the second hub 5 can be moved over the second shaft 200 under the influence of a translation of an alternative holder and/or an alternative slipper. In case of a further movement of the second hub 5 over the second shaft 200 in a longitudinal direction W towards the fourth bearing 202, the projecting portions 55 and 56 are able to mesh with an inner work 209 of the seventh chain wheel 210, which comprises cavities 155 and 156 (shown in figure 3) that at least correspond with the first and the second tooth 55 and 56. Because at least the first and the second tooth 55 and 56 of the second hub 5 are situated in the corresponding cavities of the inner work 209 of the seventh chain wheel 210, the seventh chain wheel 210 is form-closed and rotation-fixedly coupled to the second shaft 200.

In that way via a rotation-fixed coupling between the second hub 5 and the second shaft 200 a torque from the second shaft 200 can be transferred to the eighth chain wheel 21 1 (first drive wheel in the wording of the claims) or the seventh chain wheel 210 (second drive wheel in the wording of the claims) which via a chain to be driven are coupled to means to be driven of for instance a vehicle.

Figure 2 shows that the eighth chain wheel 21 1 has a larger number of teeth and/or a larger diameter than the seventh chain wheel 210. The transmission ratio related to a chain coupling the seventh chain wheel 210 to means to be driven is larger than the one related to a chain coupling the eighth chain wheel 211 to means to be driven. In case of lower speeds of the means to be driven a rotation-fixed coupling of the eighth chain wheel 211 to the second shaft 200 is preferable, whereas in case of higher speeds of the means to be driven a rotation-fixed coupling of the seventh chain wheel 210 to the second shaft 200 is preferable. In that case it does not matter by what chain transmission a torque is transferred from the first shaft 100 to the second shaft 200.

Figure 6 shows a guiding device 9 situated within the housing 2 after a lower part of the housing 2 is coupled to an upper part of the housing 2, wherein in this example, the lower part and the upper part of the housing 2 are identical. The guiding device 9 in this example comprises two partitions 91 , 92 extending transverse to the centre line v, w which coincide with the centre line 102, 103 of the first shaft 100 and the second shaft 200. The partitions 91 , 92 are connected to the housing at a bottom side 90. From a first outer end 93 of the partitions 91 , 92 facing the front side 21 of the housing 2, an arched edge 94 is formed having a radius R within which a drive chain coupled to a chain wheel can rotate freely without contacting the arched edge 94. The arched edge 94 extends between the first outer end 93 and the second outer end 95 that is situated at least near a plane which plane extends through the centre lines v, w of the first shaft 100 and the second shaft 200.

From a third outer end 96 of the partitions 91 , 92 facing the rear side 23 of the housing 2, an arched edge 9? is formed having a radius R within which a chain to be driven coupled to a chain wheel can rotate freely without contacting the arched edge 97. The arched edge 97 extends between the third outer end 96 and the fourth outer end 98 that is situated at least near a plane which plane extends through the centre lines v, w of the first shaft 100 and the second shaft 200.

Parallel to the plane through the centre lines 103, 203 (parallel to the arrows V and W) of the first shaft 100 and the second shaft 200, an edge 99 extends between the second outer end 95 and the fourth outer end 98. In this example a connecting partition 900 is placed between the two partitions 91 , 92 of the guiding device 9 for a more rigid interconnection of the partitions 91 , 92 in the direction of the centre lines 103, 203.

When mounting the gearbox 1 in a vehicle, the gear on the one hand has to be coupled to the drive via the drive chain and on the other hand to for instance wheels to be driven via the chain to be driven. When introducing the drive chain through the through-opening 22 of the housing 2, an outer end of the drive chain can for instance be arranged on the first chain wheel 1 10, after which the first chain wheel 110 can be rotated at a certain angle, wherein the drive chain can be guided to the first outer end 93 of the partition 91 , 92 by the arched edge 94. As soon as the drive chain extends close to the first outer end 93 the outer end of the drive chain can for instance be picked by hand and be coupled to the other outer end facing away from said outer end of the drive chain. In an analogous way a chain to be driven can be introduced through the through-opening 24 of the housing 2 and for instance be arranged around the seventh and/or eighth chain wheel 210, 21 1 , wherein the chain to be driven can be guided to the third outer end 96 of the partition 91 , 92 by the arched edge 97. As soon as the drive chain extends close to the third outer end 96 the outer end of the chain to be driven can for instance be picked up by hand and be coupled to the other outer end facing away from said outer end of the chain to be driven.

Guiding a chain against the arched edge 94, 97 is achieved when the edge 94, 97 has a thickness D that fits between inner links {known per se) situated opposite each other of a chain (known per se), such as a roller chain. The same effect is achieved when the edge 94, 97 has a thickness D that substantially equals the thickness of the teeth of the chain wheel.

In a second exemplary embodiment of a gear according to the invention, as shown in figures 7A and 7B, between the first drive wheel in the form a first chain wheel 310 and the second bearing 302 a first set of second drive wheels in the form of four chain wheels 322, 323, 324, 325 is placed on the first shaft 300 so as to be freely rotatable. Near each of the four chain wheels 322, 323, 324, 325 a brake member 344, 343, 342, 341 is placed at a side thereof facing away from the first chain wheel 310. Each brake member 344, 343, 342, 341 is a substantially annular part extending substantially around the first shaft 300 and placed at a side of the second drive wheel that faces away from the first drive wheel 310,

The brake member 344, 343, 342, 341 is rotation-fixedly connected to a part of the gear placed adjacent to the side of the second drive wheel 322, 323, 324, 325 facing away from the first drive wheel and comprises a brake surface 364, 363, 362, 361 facing the second drive wheel 322, 323, 324, 325. In the exemplary embodiment of figure 7A and 7B, and as shown in more detail in figure 8, a first brake member 341 is rotation-fixedly connected to the housing 2 by means of a cam 381 placed in a recess 351 of the housing 2. A second brake member 342 is rotation-fixedly connected to a second drive wheel 325 placed adjacent to the housing 2 by means of a cam 382 placed in a recess 352 of said second drive wheel 325. A third brake member 343 is rotation-fixedly connected to the next second drive wheel 324 by means of a cam 383 placed in a recess 353 of said second drive wheel 324. A fourth brake member 344 is rotation-fixedly connected to the next second drive wheel 323 by means of a cam (not shown) placed in a recess (not shown) of said second drive wheel 323. The recesses in the drive wheels 323, 324, 325 are formed as through-holes.

Both the second drive wheels 322, 323, 324, 325 and the brake members 344, 343, 342, 341 are placed on the first shaft 300 with clearance, so that a slight shifting of the second drive wheels 322, 323, 324, 325 along the first shaft 300 is possible. When the coupling means, particularly the fingers or pins 334 thereof, are moved in the direction of the second drive wheel 322 and do not directly drop into the openings {see figures 4A and 4B) made for that purpose in the second drive wheel, the pins 334 will push against the side of the second drive wheel 322. Due to the clearance the entire stack of second drive wheels and the brake members situated in between will be pushed against each other, as a result of which the brake surfaces 364, 363, 362, 361 will push against the sides of the second drive wheels

322, 323, 324, 325, and as a result of which the entire stack of second drive wheels are braked. In case of a lower speed of the second drive wheels the pins 334 can more easily and reliably couple to the second drive wheel 322 and/or to one or more of the next drive wheels

323, 324, 325.

In a first alternative embodiment as shown in figure 9 the brake members 444, 443, 442, 442 are rotation-fixedly connected to the second drive wheel 422, 423, 424, 425 and provided with a brake surface 464, 463, 462, 461 facing a part of the gear placed adjacent to a side of the second drive wheel 422, 423, 424, 425 facing away from the first drive wheel 410. A first brake member 441 is rotation- fixedly connected to the second drive wheel 425 placed adjacent to the housing 2 by means of a cam 481 placed in a recess of said second drive wheel 425, and at a side facing the housing 2 is provided with a brake surface 461. A second brake member 442 is rotation-fixedly connected to next second drive wheel 424 by means of a cam 482 placed in a recess of said second drive wheel 424, and at a side facing the adjacent second drive wheel 425 is provided with a brake surface 462. A third brake member 443 is rotation-fixedly connected to the next second drive wheel 423 by means of a cam (not shown) placed in a recess of said second drive wheel 423, and at a side facing the adjacent second drive wheel 424 is provided with a brake surface 463. A fourth brake member 444 is rotation-fixedly connected to the next second drive wheel 422 by means of a cam {not shown) placed in a recess of the second drive wheel 422, and at a side facing the adjacent second drive wheel 423 is provided with a brake surface 464.

Both the second drive wheels 422, 423, 424, 425 and the brake members 444, 443, 442, 441 are placed on the first shaft 400 with clearance, so that the second drive wheels 422, 423, 424, 425, so that a slight shifting of the second drive wheels 422, 423, 424, 425 along the first shaft 400 is possible. Here again the second drive wheels 422, 423, 424, 425 are placed on the first shaft 400 so as to be substantially freely rotatable around the first shaft 400. The operation of the brake members 444, 443, 442, 441 is comparable to the description referring to figure 8.

In a second alternative embodiment as shown in figure 10, the brake members 544, 543, 542, 541 are all rotation-fixedly connected to the housing 2 by means of connection members 554, 553, 552, 551. Both the second drive wheels 522, 523, 524, 525 and the brake members 544, 543, 542, 541 are placed on the first shaft 500 with clearance so that a slight shifting of the second drive wheels 522, 523, 524, 525 along the first shaft 500 is possible. Here again the second drive wheels 522, 523, 524, 525 are placed on the first shaft 500 so as to be substantially freely rotatable around the first shaft 500. The operation of the brake members 544, 543, 542, 541 is comparable to the description referring to figure 8, the difference being that none of the brake members 544, 543, 542, 541 rotates along with one of the second drive wheels 522, 523, 524, 525, as a result a more effective brake action can be achieved. In the examples described above and shown in figures 7A, 7B, 8, 9 and 10 the brake members are shaped like cylinders spaced apart around the first shaft and provided with a brake surface extending substantially transverse to the first shaft, and wherein the brake surface is placed near a side surface of the second drive wheel facing the brake member or a part of the gear. The brake members are provided with annular brake surfaces which when braking abut a side surface of the second drive wheels.

The above description is included to illustrate the operation of preferred embodiments of the invention and not to limit the scope of the invention. Starting from the above explanation many variations that fall within the spirit and scope of the present invention will be evident to an expert. For instance in the gear 1 chain transmissions can be placed wherein the second chain wheel 130, the third chain wheel 122, the fourth chain wheel 123, the fifth chain wheel 124 and the sixth chain wheel 125 are coupled by a separate chain to the ninth chain wheel 230, the tenth chain wheel 222, the eleventh chain wheel 223, the twelfth chain wheel 224 and the thirteenth chain wheel 225, respectively. Instead of the chain transmissions for instance belt transmissions can be used, wherein the chains may have been replaced by a belt or a toothed belt and wherein the chain wheels have been replaced by a drive wheel onto which the belt engages by friction or a drive wheel provided with external teeth, respectively. Other variants thereon can be formed by for instance using a gear wheel transmission, wherein the chain wheels have been replaced by gear wheels provided with external teeth. In case of a gear wheel transmission a direction of rotation of the first gear wheel placed on the first shaft 100, which first gear wheel meshes with a second gear wheel placed on the second shaft 200, is opposite to a direction of rotation of the second gear wheel. The mutually opposite direction of rotation may for instance be compensated by placing a third gear wheel on a third shaft between the first shaft 100 and the second shaft 200 (not shown), wherein the first gear wheel meshes with the third gear wheel and the third gear wheel meshes with the second gear wheel.

In this invention it does not matter whether the transmissions present in the gear are designed like chain transmissions, belt transmissions, gear wheel transmissions or an alternative transmission. That is why when this patent application mentions a chain, a chain wheel and a chain transmission, or a transmission means, respectively, a drive wheel and/or wheel to be driven and a transmission can be read.

Summarising the invention provides a gear and gearbox having such a gear, comprising a first shaft comprising a first and a second drive wheel, a second shaft comprising a first and a second wheel to be driven, wherein the first drive wheel and the second drive wheel, respectively, are coupled to the first wheel to be driven and the second wheel to be driven, respectively, wherein at least the second drive wheel is placed on the first shaft so as to be freely rotatable, and a gear change means that can be moved parallel to and over the first shaft so as to mesh with a drive wheel, wherein the first drive wheel is placed between the gear change means and the second drive wheel, and comprises an opening, wherein the gear change means is rotation- fixedly connected to a coupling means extending along the first shaft and adapted for engaging through the opening of the first drive wheel onto the adjacently situated second drive wheel, for a rotation-fixed coupling between the gear change means, the first drive wheel and the second drive wheel.

Claims

1. Gear comprising: a first shaft comprising a first and a second drive wheel, a second shaft comprising a first and a second wheel to be driven, wherein the first drive wheel is coupled to the first wheel to be driven and the second drive wheel is coupled to the second wheel to be driven, wherein at least the second drive wheel is placed on the first shaft so as to be freely rotatable, and a gear change means that can be moved parallel to and/or over the first shaft so as to mesh with one of the drive wheels, characterised in that at least the first wheel to be driven is placed on the second shaft via a freewheel coupling, and that the first drive wheel is placed between the gear change means and the second drive wheel, and comprises an opening, wherein the gear change means is rotation fixedly connected to a coupling means extending along the first shaft and adapted for engaging through the opening of the first drive wheel onto the adjacently situated second drive wheel, for a rotation- fixed coupling between the gear change means, the first drive wheel and the second drive wheel.

2. Gear according to claim 1 , wherein a first transmission ratio of a first transmission between the first drive wheel and the first wheel to be driven is smaller than a second transmission ratio of a second transmission between the second drive wheel and the second wheel to be driven.

3. Gear according to claim 1 or 2, wherein adjacent to the second drive wheel at a side facing away from the first drive wheel, one or more further drive wheels are placed on the first shaft so as to be freely rotatable and which have each been coupled to one or more further wheels to be driven placed on the second shaft for forming a series of adjacently placed transmissions.

4. Gear according to claim 3, wherein the second and/or the further drive wheels comprises and/or comprise an opening through which the coupling means can engage onto the second and/or the further drive wheels for a rotation-fixed coupling between the gear change means and one or more of the drive wheels.

5. Gear according to claim 3 or 4, wherein considered from the gear change means the transmission ratios of the adjacently placed transmissions increase.

6. Gear according to any one of the preceding claims, wherein the coupling means comprises at least one first finger that extends substantially parallel to the first shaft towards the drive wheels, wherein the finger is adapted for extending through the openings of the drive wheels, wherein the dimensions of the finger are smaller than or equal to the dimensions of the openings.

7. Gear according to claim 6, wherein the finger tapers in a direction of the drive wheels.

8. Gear according to claim 6 or 7, wherein the finger is placed on the outside of the first shaft.

9. Gear according to claim 8, wherein the finger is spaced apart from the first shaft.

10. Gear according to any one of the preceding claims, wherein the gear change means comprises an engagement part on which an operating means can engage for moving the gear change means substantially parallel to and/or over the first shaft.

1 1 . Gear according to claim 10, wherein the engagement part is formed substantially rotation symmetrical with respect to the first shaft.

12. Gear according to claim 10 or 1 1 , wherein the operating means comprises a slipper for engaging onto the engagement part of the gear change means.

13. Gear according to any one of the preceding claims, wherein the operating means comprises a holder for the slipper, wherein the holder is rotatabiy positioned about an operating axle extending substantially transverse to a direction of movement of the gear change means.

14. Gear according to claim 13, wherein the operating means comprises a holder on which the slipper is rotatabiy positioned about a hinge pin extending substantially transverse to a direction of movement of the gear change means.

15. Gear according to any one of the preceding claims, wherein the gear change means when the coupling means meshes with the second drive wheel, is only rotation-fixedly coupled to the second drive wheel.

16. Gear according to claim 15, wherein the coupling means at an outer end facing the drive wheels is provided with radially extending teeth.

17. Gear according to claim 16, wherein the drive wheels comprise recesses for receiving the radially extending teeth of the coupling means.

18. Gear according to any one of the preceding claims, wherein the first drive wheel is placed on the second drive wheel so as to be rotatable.

19. Gear according to any one of the preceding claims, wherein the gear change means and the coupling means are integrally formed.

20. Gear according to any one of the preceding claims, wherein the gear change means on either side is provided with coupling means adapted for engaging through the opening of a drive wheel onto the adjacently situated drive wheel, for a rotation-fixed coupling between the gear change means and a drive wheel.

21 . Gear according to any one of the claims 1 -20, wherein the drive wheels are coupled to said to be driven by means of transmission belts.

22. Gear according to claim 21 , wherein the drive wheels and the wheels to be driven are designed like toothed wheels and wherein the transmission belts are designed like geared belts or toothed belts.

23. Gear according to claim 21 , wherein the drive wheels and the wheels to be driven are designed like chain wheels and wherein the transmission belts are designed like chains.

24. Gear according to any one of the claims 1 -20, wherein the first drive wheels and the first wheels to be driven comprise meshing gear wheels, and further drive wheels and further wheels to be driven comprise meshing gear wheels, preferably with one or more connecting gear wheels placed between the first drive wheels and the first wheels to be driven, the further drive wheels and the further wheels to be driven, respectively.

25. Gear according to any one of the preceding claims, wherein a brake member is placed near the second drive wheel, which brake member when activated brakes the drive wheel.

26. Gear according to claim 25, wherein the brake member extends substantially around the first shaft and is placed at a side of the second drive wheel which side faces away from the first drive wheel.

27. Gear according to claim 26, wherein the brake member is rotation- fixedly connected to a part of the gear placed adjacent to the side of the second drive wheel which side faces away from the first drive wheel and comprises a brake surface that faces the second drive wheel.

28. Gear according to claim 26, wherein the brake member is rotation- fixedly connected to the second drive wheel and comprises a brake surface facing a part of the gear placed adjacent to the side of the second drive wheel that faces away from the first drive wheel.

29. Gear according to claim 27 or 28, wherein the brake surface extends substantially transverse to the first shaft and wherein the brake surface is placed near a side surface of the second drive wheel facing the brake member or a part of the gear.

30. Gear according to claim 27, 28 or 29, wherein the part of the gear placed adjacent to the side of the second drive wheel that faces away from the first drive wheel comprises a further drive wheel or a part of the housing of the gear.

31 . Gear according to any one of the claims 25-30, wherein the brake member is made of synthetic material.

32. Gear according to any one of the claims 25-31 , wherein the brake member comprises a through-opening for passing the coupling means through.

33. Gearbox placed between a drive and wheels to be driven, wherein the gearbox comprises a gear according to any one of the preceding claims.

34. Gearbox according to claim 33, wherein the drive comprises a pedal drive.

35. Gearbox according to claim 33 or 34, wherein the gear is accommodated in a housing that is provided with a first through- opening for a coupling of the gear to the first shaft.

36. Gearbox according to claim 33, 34 or 35, wherein the gear is accommodated in a housing that is provided with a second through- opening for a coupling of the gear to the second shaft.

37. Gearbox according to any one of the claims 33-36, wherein the gear is accommodated in a housing provided with a guiding device adapted for guiding a chain during its insertion when mounting the chain around a chain wheel of the gear.

38. Gearbox according to claim 37, wherein the guiding device comprises an edge that is spaced apart from at least a part of the circumference of the chain wheel on which the chain can be mounted.

39. Gearbox according to claim 38, wherein the edge has a thickness extending between opposed inner links of a chain.

40. Gearbox according to claim 39, wherein the edge has a thickness that substantially equals a thickness of the teeth of a chain wheel.

41. Children's vehicle, particularly a pedal car, having a drive for driving wheels to be driven, wherein the children's vehicle is provided with a gearbox according to any one of the claims 33-40, wherein the gearbox is placed between the drive and the wheels to be driven.