The invention relates to a shifting device for a gear unit. The invention relates particularly to a shifting device for shifting between gears of a gear unit for a cycle.

The correct gear during cycling is of great importance for the comfort of the rider. It is therefore important that it is possible to change gear at all times and under all circumstances. Gear hubs, and the gearboxes for cycles now being seen more and more, provide these options. They are in addition maintenance-friendly and robust.

The commercially available Rohloff Speedhub gear hub of the German company Rohloff GmbH, which forms the subject-matter of DE-A1-197 20 794, is an example of such a gear hub. This gives the cyclist the option of shifting 14 gears by means of an enclosed gear system. Owing to this gear system, which is located in the rear wheel, it is possible to shift while travelling, while standing still and even while pedalling backwards.

Shifting takes place with a twist shifter which is mounted on the inner side in the line of the right handgrip and connected via two cables to the hub. These two cables move simultaneously in opposite directions. The associated twist shifter is however not suitable for operation in all conditions, whereby the potential of the hub cannot be fully utilized.

In wet weather conditions the grip of the cyclist on the twist shifter can decrease such that the adjustment of the twist shifter is very difficult. A great squeezing force is in this case required to prevent the fingers sliding over the twist shifter.

Particularly in the case of the so-called downhill mountain bikes, wherein a descent is made at great speed on an unpaved slope, a twist shifter has great limitations. This is particularly because the unpaved slope results in a wild ride, wherein the cyclist has to hold the handlebars very tightly. It is then very difficult, and even dangerous, to rotate a twist shifter since it would then be easy to lose control of the handlebars.

A twist shifter is also unsuitable for people with wrist problems.

In summary, a twist shifter for a gear hub for cycles represents a limiting factor in being able to wholly and safely utilize the full potential of such a gear hub.

In addition, the twist shifter as is currently available for instance for the Rohloff Speedhub is in a number of ways not user-friendly and, in the case of a curved racing bike handlebar, cannot be mounted at the desired position.

The invention now has for its object to provide a shifting device of the above described type wherein said drawbacks do not occur, or at least do so to lesser extent. The invention has the particular object that the potential of the gear hub can be utilized more fully and more safely.

Said object is achieved with the shifting device for shifting between gears of a gear unit according to the invention, comprising: - a first shift member with a first reel arranged in a first housing, wherein in a rest position this first reel can rotate substantially freely in at least an unrolling direction and in an operative position is engageable with a catch mechanism such that the first reel is rotatable in a roll-up direction using the catch mechanism;

- a second shift member with a second reel arranged in a second housing, wherein in a rest position this second reel can rotate substantially freely in at least an unrolling direction and in an operative position is engageable with a catch mechanism such that the second reel is rotatable in a roll-up direction using the catch mechanism;

- one or more substantially flexible pull members connected to at least one reel such that they are reliable onto this reel in the roll-up direction and unreliable from this reel in the unrolling direction; and

- wherein the one or more pull members are connected engageably to an adjusting member of the gear unit and connect the first and the second reel directly or indirectly to each other via the gear unit.

According to a preferred embodiment, the shifting device is configured, when one of the two shift members is operated, to roll the pull member connected thereto in the roll-up direction onto the reel of this respective shift member and to simultaneously unroll the pull member connected to the reel of the other shift member the same length in the unrolling direction from the reel, wherein the one or more pull members adjust the adjusting member of the gear unit.

In the embodiment where two pull members are applied each of the two pull members forms a flexible connection between a reel of a shift member and the adjusting member of the gear unit. When this adjusting member is adjusted using one of the two shift members, this adjustment will be transmitted via the other pull member to the other shift member. The reel present there in rest position will then rotate and unroll and release a part of the pull member in order to allow this adjustment of the adjusting member of the gear unit. It is alternatively possible for a single pull member to be applied which is arranged engageably with the adjusting member and runs from the reel of a first shift member via the adjusting member to the other reel of the second shift member.

Causing a limited friction between the reel and its rotation shaft according to a particularly advantageous embodiment, for instance using a close fit around this rotation shaft or having the reel run along a friction surface, prevents rotation of the reel in the rest position and thereby undesirable unrolling and slackening of the flexible pull member.

Provided according to an alternative embodiment is a torsion spring which biases the reel around the rotation shaft. Such a torsion spring makes it unnecessary to apply a limited friction, whereby the resistance during shifting becomes lighter and shifting more comfortable.

According to a further preferred embodiment, one or more of the substantially flexible pull members comprise a cable. A cable is a flexible and readily obtainable pull member which can also be easily carried in rolled-up state as spare part in a saddlebag. A cable can moreover be replaced on the spot using limited tools, so also during a cycling trip.

It is noted that, although a cable is a particularly advantageous embodiment, a toothed belt or chain can for instance be applied as alternative. It is moreover possible to envisage the pull member comprising a cable close to its outer ends which have to be rollablc onto the reels, but having an alternative embodiment, for instance as toothed belt or chain, in the part which engages with the adjusting member of the gear unit.

According to yet another preferred embodiment, the adjusting member of the gear unit is a pulley or shaft around which the cable is wound one or more times. When the cable is rolled up onto the reel of one of the two shifting devices and unrolled from the reel of the other shifting device, this cable will cause the pulley or the shaft around which the cable is wound to rotate, whereby the gear unit can be set in another gear.

In the case that a single cable is applied as pull member, this cable is arranged with one or more windings round the adjusting member and the cable is in direct connection at each of its outer ends with a reel of the shifting device.

In the embodiment where for instance two cables are applied, each of these cables is connected with one outer end to a reel and the other outer end is wound one or more times round an adjusting member of the gear unit. The adjusting member in this case provides an indirect connection between the two cables.

It is also possible to envisage the gear unit being a gearbox comprising for instance two output shafts as adjusting members. One cable will in this case be connected to a first adjusting member and the other cable to the second adjusting member. In this embodiment the adjusting members provide an indirect connection between the two cables via the gear unit.

A particularly advantageous embodiment results when the shift member is provided with a lever which brings the catch mechanism into engagement with the reel.

According to a further preferred embodiment, the reel is connected substantially non- rotatably to a toothed wheel and the catch mechanism is engageable with this toothed wheel. A shifting device is hereby provided wherein in a rest position the reel can rotate substantially freely in order to allow the cable to unroll, while in an operative position the reel has a reliable engagement.

According to a further preferred embodiment, the lever is biased with a spring, wherein the spring brings the lever into a rest position when it is not being operated, and wherein the catch mechanism comprises a pivotable engaging member which is biased with a spring such that this spring brings the engaging member into engagement with the toothed wheel in an operative position wherein the lever is operated by a user. According to yet another preferred embodiment, in the rest position in which the lever is not being operated the engaging member moves against a projecting member arranged in the housing of the shift member, whereby the biasing force of the spring of the engaging member is overcome and the engaging member is disengaged from the toothed wheel.

According to yet another preferred embodiment, the gear unit is more preferably a cycle gear unit comprising a gear hub or a gearbox.

When according to yet another preferred embodiment the housing of the first shift member and the housing of the second shift member are integrated into a single housing, a cyclist can shift up and down with a single hand. Such an integrated housing can be arranged as desired on the left or right-hand half of the handlebar.

Preferred embodiments of the present invention are further elucidated in the following description with reference to the drawing, in which:

Figure 1 is a perspective view of a cycle with a gear hub and a shifting device according to the invention;

Figure 2 is a schematic view of the combination of gear hub and shifting device shown in figure 1;

Figure 3A is a schematic view of the shifting device in a rest position;

Figure 3B is a schematic view of the shifting device in an operative position;

Figure 4 is a perspective top view of a shift member according to the invention;

Figure 5 is a perspective bottom view of the shift member shown in figure 4;

Figure 6 is a cut-away view of the shift member shown in figures 4 and 5; and

Figure 7 is a perspective view of a shifting device wherein both shift members are incorporated in one integrated housing.

The cycle 2 shown in figure 1 is a mountain bike wherein a first shift member 10 and a second shift member 40 of a shifting device 1 according to the invention are arranged on handlebar 4. These shift members 10, 40 are connected via cables 34 to a gear hub 6 arranged in the rear wheel of cycle 2. In order to adjust gear hub 6 cables 34 engage on an adjusting member 8 of this gear hub 6.

Figure 2 shows an enlarged view of the configuration of figure 1. Shift members 10, 40 are provided with levers 14, 44 with which the cyclist can adjust gear hub 6. This adjustment principle will be further elucidated with reference to figures 3 A and 3B, wherein figure 3 A shows a schematic view of a rest position.

In the rest position of shifting device 1 shown in figure 3 A both levers 14, 44 are in a rest position, whereby the catch mechanisms 18, 48 connected to these levers 14, 44 are disengaged from toothed wheels 20, 50. Reels 16, 46 are fixed to respective toothed wheels 20, 50, whereby in the rest position shown in figure 3 A first reel 16 and second reel 46 can rotate substantially freely around their respective rotation shafts 26, 56.

Both catch mechanisms 18, 48 comprise an engaging member 30, 60 which are biased by a spring (not shown) such that they are pushed in the direction of toothed wheels 20, 50. In the rest position shown in figure 3 A levers 14, 44 arc however situated at a position such that the engaging members 30, 60 connected thereto move against projecting members 32, 62 arranged in the housing of shifting device 1. These projecting members 32, 62 push engaging members 30, 60 counter to their spring bias and in this way ensure that engaging members 30, 60 are disengaged from toothed wheels 20, 50 when levers 14, 44 are in a rest position.

When the cyclist wishes to change gear, he/she will push against one of the two levers 14,

44. In the situation shown in figure 3B the cyclist pushes lever 44 forward, whereby engaging member 60 connected to lever 44 moves away from projecting member 62 and, because of the spring bias, rotates about the rotation shaft 61 in the direction of second toothed wheel 50, with which it subsequently engages. When the user displaces lever 44 further, engaging member 60 will co-displace toothed wheel 50, and the second reel 46 connected non-rotatably to this toothed wheel 50 will thereby rotate in the roll-up direction O and wind up cable 34. The first shift member 10 is at the same time still in the rest position shown in figure 3, whereby even in the situation shown in figure 3B first reel 16 can rotate substantially freely around rotation shaft 26. As much cable length 34 will unroll from first reel 16 as will be rolled up onto second reel 46 on second shift member 40.

While the cable rolls up onto second reel 46 and unrolls from first reel 16, this cable displaces from first shift member 10 in the direction of second shift member 40, wherein cable 34 drives adjusting member 8 of gear unit 6 in the adjusting direction V.

It is noted that when changing gear a cyclist determines with the distance he/she displaces the lever 14, 44 the rotation over which the engaging member 30, 60 of catch mechanism 18, 48 co-displaces toothed wheel 20, 50, so that it is possible to shift up or down one or more gears as desired in a single pushing movement.

The second shift member 40 is elucidated in more detail in figures 4-6, wherein it is noted that first shift member 10 has a corresponding though mirrored form. Second shift member 40 comprises a housing 42 and a lever 44 and is mountable with a handlebar mounting ring 64 on handlebar 4 of cycle 2.

In order to show the different components clearly the second shift member 40 shown in figures 4 and 5 is shown in cut-away and exploded view in figure 6. Second reel 46 comprises a cable channel 66 in which cable 34 can be received. Second reel 46 and second toothed wheel 50 are lockable non-rotatably using looking members (not shown) by arranging a locking member in openings 52, 54. When lever 44 is operated outside housing 42, a lever 45 on which an engaging member 60 is arranged rotatably around a shaft 61 rotates inside housing 42. This engaging member 60 is biased with a spring (not shown) and in the situation shown in figure 6 is forced by a projecting member 62 into a position in which it is disengaged from the teeth of second toothed wheel 50.

A particularly advantageous embodiment wherein a user can shift up and down with one hand is shown in figure 7. Both shift members 10, 40 are incorporated in one integrated housing 66 of an integrated shift member 72. Housing 66 is provided with a first passage opening 68 and a second passage opening 70 through which opposite outer ends of a cable 34, which is connected to an adjusting member 8 of a gear unit 6, are feedable. In the integrated housing 66 the outer ends are coupled to respectively a first shift member 10 and a second shift member 40. These shift members 10, 40 correspond to the embodiment described with reference to figures 2-6, and for the operation thereof reference is therefore made to this description. Because both shift members 10, 40 are integrated into one housing 66, in this embodiment first lever 14 of first shift member 10 and second lever 44 of second shift member 40 are situated close to each other and on the same handlebar half of handlebar 4.

It is noted that the embodiment shown in figure 7 is suitable for placing on a right-hand handlebar half. A mirrored embodiment (not shown) is suitable for placing on a left-hand handlebar half.

For the embodiment shown in figures 1-6 and for that shown in figure 7 it is the case that a user can connect the one or the other outer end of cable 34 as desired to first shift member 10 and second shift member 40. The user can hereby select the levers 14, 44 of his/her choice for the purpose of shifting gear unit 6 up and down.

Although it shows a preferred embodiment of the invention, the above described embodiment is intended solely to illustrate the present invention and not to limit the scope of the invention in any way. Although the invention is described with reference to a gear hub, the principle can also be applied to any gearbox wherein the adjustment takes place by rotating a shaft.

It is moreover noted that the invention is elucidated with a single cable 34 running between the two reels 16, 46 as pull member, but that the invention can be applied in similar manner with a first pull member 34 between first shift member 10 and an adjusting member and a second pull member 34 between second shift member 40 and an adjusting member 8 of gear unit 6. It is even possible to envisage separate adjusting members 8 being arranged on the gear unit for the purpose of changing up and down.

The rights described are defined by the following claims, within the scope of which many modifications can be envisaged. Where measures in the claims are followed by reference numerals, such reference numerals serve only to contribute toward the understanding of the claims, but are in no way limitative for the scope of protection.