Abstract:
A device for hand-driven operation of a guided wheel arranged on a steering gear is pivotable about a steering axis perpendicular to the wheel&#39;s axis of rotation. The device includes first and second handles, first and second coupling devices respectively arranged thereon, and a power transmission train coupled to transmit traction power to the second coupling device via coupling points for transmitting handle movement to a drive device cooperating with the guided wheel&#39;s hub. The power transmission train extends from the first coupling device via deflecting elements, thereby modifying the extension direction of the train, in a second power transmission section to the second coupling device such that the coupling devices move the coupling points of the train on substantially linear drive paths approaching and absenting of a symmetrical plane of guidance which is oriented in a perpendicular manner in relation to the axis of rotation of the guided wheel.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   Applicant claims priority under 35 U.S.C. §119 of German Application No. 10 2004 018 662.6 filed Apr. 13, 2004 and German Application No. 10 2004 031 976.6 filed Jun. 25, 2004. Applicant also claims priority under 35 U.S.C. §365 of PCT/DE2004/002268 filed Oct. 8, 2004. The international application under PCT article 21(2) was not published in English. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a device for hand-driven operation of a guided wheel. 
   2. Description of the Related Art 
   A multiplicity of hand-driven devices are known from the prior art, which, particularly in the case of bicycles, ensure, in addition to the known foot-pedal drive, an additional hand-operated auxiliary drive of one of the wheels. 
   DE 101 06 283 A1 discloses a device for hand-driven operation of a guided wheel which is arranged on a steering gear and which is pivotable about a steering axis oriented perpendicularly with respect to the axis of rotation of the guided wheel. 
   This device comprises a first handle with a first coupling means arranged on the first handle and a second handle with a second coupling means arranged on the second handle. The first and the second coupling means are coupled via coupling points, so as to transmit tractive force, to a force transmission train for transmitting a movement of the handles to a drive means cooperating with the hub of the guided wheel. The drive means converts the movement of the handles into a rotational movement of the guided wheel with the aid of the force transmission train. 
   Furthermore, a guide means is provided, which is pivotable about the steering axis and cooperates mechanically with the steering gear. The guide means ensures, furthermore, that the handles are mounted movably. For this purpose, the guide means has a mechanical positive guide such that the handles can be moved symmetrically with respect to a steering plane of symmetry in which the steering axis lies and which is oriented perpendicularly to the axis of rotation of the guided wheel. 
   The coupling means of the device known from DE 101 06 283 A1 are designed as two chain wheels spaced axially apart from one another. These have drive levers arranged radially on the gearwheels and having the handles. On each of the two sides of the hub of the guided wheel, a toothed drive pinion having a freewheel is arranged, the force transmission train in the form of a link chain being guided between the toothed drive pinions and the chain wheels of the coupling means. In order to provide a handy step-up of the drive device, it is necessary to design the diameter of the chain wheels of the coupling means so as to be markedly larger than the diameter of the toothed drive pinions. To actuate the drive, it is necessary to set the chain wheels of the coupling means in an alternating rotational movement by means of the radial drive levers. On account of the abovementioned size ratios of the diameters, the result of this is that the moved parts of the hand-operated drive have comparatively high moments of inertia and the device as a whole possesses an appreciable weight. 
   SUMMARY OF THE INVENTION 
   The object on which the present invention is based is, therefore, to provide a device for hand-driven operation of a guided wheel, the moved parts of which have a lower mass or a lower mass moment of inertia, so that the device as a whole is more weight-saving and can be operated more easily. 
   This object is achieved by means of a device having the features in accordance with the invention. 
   According to the invention, there is provision for the force transmission train to extend from the first coupling means via deflection elements, which cause a change in the direction of extent of the force transmission train, in a first force transmission portion, to the drive means and from the drive means, via deflection elements which cause a change in the direction of extent of the force transmission train, in a second force transmission portion, to the second coupling means, in such a way that the coupling means moves the coupling points of the force transmission train on essentially rectilinear drive paths. 
   Due to the use of deflection elements which cause a change, in the direction of extent of the force transmission train, the coupling means and therefore the handles can be guided in such a way that the coupling points of the force transmission train move on essentially rectilinear drive paths. It is thereby possible to design the moved parts of the device so as to be smaller and lighter. 
   The feature “essentially rectilinear” is understood here to mean that not only drive paths of the coupling points which are rectilinear in the strictly geometric sense are covered, but also slightly curved drive paths. That is to say, a ratio of the length deviation of the coupling point from a strictly rectilinear drive path to the overall length of the drive path which does not overshoot a value of 1:10 is still considered as slightly curved and therefore as being essentially rectilinear within the meaning of the present invention. 
   Coupling points within the meaning of the present invention are all regions of the coupling means which are connected to the force transmission train so as to transmit tractive force. 
   The force transmission train may be designed both in one piece and as a combination of a plurality of subportions. It is essential in this case only that the subportions are connected to one another in such a way that force transmission becomes possible. For the force transmission train, for example, ropes, chains or belts, in particular toothed belts, which can absorb the tractive forces which arise, are suitable. In this case, it is advantageous if the force transmission train, at least in the region of the first and the second force transmission portion, has no appreciable elastic length variation and/or has a low dead weight. 
   Preferably, the drive device is designed in such a way that a length change, induced by the movement of the handles, of the first force transmission portion causes a length change of opposite sign and of identical amount of the second force transmission portion. The symmetry of the handle movement is thus accompanied by a symmetrical length change of the two force transmission portions. 
   The handles can in this case be moved on a multiplicity of rotational and/or translational handle guide paths. What is essential in each case is only the symmetry of the handle guide paths with respect to the steering plane of symmetry. 
   The guide paths have in each case two guide path end portions. The handles can be moved back and forth between the guide path end portions in alternating movements symmetrically with respect to the steering plane of symmetry. 
   Preferably, spring elements are provided in such a way that, during the movement of the handle in the region of the guide path end portions, a spring force oriented opposite to the direction of movement of the handles is built up. The spring elements thereby also function as energy accumulators which release the introduced energy again upon the reversal of movement. 
   In a first variant of the device according to the invention, the positive guidance of the handles is implemented in such a way that the force transmission train, starting from the first coupling means, forms a coupling portion which is connected via a coupling deflection element to the second coupling means so as to transmit tractive force, and the two force transmission portions ( 30 ,  31 ) are coupled to one another via the drive means  4  so as to transmit tractive force. 
   Thus, the drawing of the two handles apart from one another gives rise, with the aid of the coupling portion of the force transmission train, to a corresponding symmetrical movement of the second handle. When the handles are pressed together, the tractive force-transmitting connection of the first and of the second force transmission train ensures a symmetrical positive control of the handle movement. 
   So that the symmetry of the handle movements with respect to the steering plane of symmetry is ensured, it is necessary that the coupling deflection element deflects the coupling portion of the force transmission train with respect to its spatial direction of extent. 
   It is particularly simple if the coupling deflection element deflects the force transmission train through essentially 180 degrees. This ensures that the movement of the handles is oriented symmetrically with respect to the steering plane of symmetry and no further deflection element for the coupling portion of the force transmission train is required between the coupling deflection element and the second coupling means. 
   A simple symmetrical construction of the device is obtained in that the second force transmission portion of the force transmission train has a force transmission deflection element for deflecting the direction of extent of the second force transmission portion, this force transmission deflection element being oriented mirror-symmetrically with respect to the steering axis in relation to the coupling deflection element of the coupling portion. 
   The steering gear for receiving the guided wheel preferably has a fork which is designed and arranged symmetrically with respect to the steering plane of symmetry. Furthermore, the steering gear comprises a steering shaft arranged on the fork and extended along the steering axis. Preferably, a crossmember extending transversely with respect to the steering axis is fastened to the steering shaft. The coupling deflection element and the force transmission deflection element are fixed to the end portions of said crossmember. In order to ensure the symmetry of the handle movements, the crossmember is preferably designed symmetrically with respect to the steering plane of symmetry at least in terms of the positioning of its end portions. 
   It is, of course, also conceivable that the steering gear has, instead of a fork, a bearing arm on which the guided wheel is mounted. In this case, it is not mandatory that the bearing arm be oriented so as to lie in the steering plane of symmetry. 
   A first and a second force deflection element are fixed to the steering shaft and/or to the crossmember, in order to deflect the first and the second force transmission portion of the force transmission train in the direction of the drive device. The drive means is in this case arranged conventionally in the region of the hub or of the fork of the steering gear. 
   In a preferred embodiment of the drive device, the crossmember has two sliding portions designed symmetrically with respect to the steering plane of symmetry. The handles are in this case designed in such a way that, together with the assigned coupling means, they are movable back and forth along these sliding portions. 
   In order to prevent a pivoting of the handles about the sliding axis, on the one hand, both the handle and the crossmember can be designed in the region of the sliding portions, with respect to their cross-sectional geometry, in such a way that a pivoting of the handle about the sliding axis is blocked. On the other hand, alternatively or additionally, there may be provision for providing, essentially parallel to the sliding portions, a guide rail which is spaced apart on the crossmember and which cooperates with stabilizing elements, arranged on the handles, for stabilizing the movement of the handles. The term “stabilization of the movement of the handles” is to be understood here as meaning that, when the device is in use, the handles can be moved essentially only along the sliding axes defined by the sliding portions, even in the event of strong forces acting on said handles. 
   With the proviso of the symmetry with respect to the steering plane of symmetry, it is conceivable for the sliding portions to have both a strictly rectilinear and a slightly curved design. 
   In a further variant of the drive device, the symmetrical movement of the handles is implemented via symmetrical lever movements. For this purpose, the first and the second handle are designed as an end portion of a first and of a second lever arm, the lever arms being articulated on the steering gear in such a way that the first and the second handle can be pivoted essentially adjacently to the crossmember. 
   In each case the coupling means having the coupling points for the force transmission train is arranged on the lever arms. In this case, it may be advantageous to mount the coupling points movably with respect to the coupling means in such a way that the handle guide path, necessarily curved due to the lever movement, entails a less highly curved drive guide path of the coupling points. For this purpose, the coupling points are mounted on the coupling means so as to be displaceable within a defined deflection range along an axis which extends parallel to the direction of extent of the levers. The movement of the coupling points on the drive guide paths is designed essentially rectilinearly according to the above definition both for a movable and for a fixed mounting of the coupling points. 
   Preferably, there is provision, in the case of a fork which has a fork head in a known way, for the lever arms to be articulated symmetrically with respect to the steering plane of symmetry in the region of the fork head. However, another type of positioning of the lever arms, for example in the region of the steering shaft, may likewise be envisaged. 
   A further variant of the device according to the invention provides positive guidance between the first and the second handle without the use of a coupling portion, acting between the two coupling means, of the force transmission train. 
   For this purpose, the handles are designed as end portions of a first and of a second lever arm of L-shaped design. The lever arms are arranged symmetrically with respect to the steering plane of symmetry and are in each case pivotable about a pivot axis running outside the steering plane of symmetry. This pivot axis is preferably arranged in the angled region of the L-shaped lever arms. By means of the end portions, facing away from the handles, of the two L-shaped lever arms, these are mounted in a common bearing means arranged in the region of the steering plane of symmetry, in such a way that the pivoting movement of one lever arm necessarily induces a symmetrical pivoting movement of the other lever arm due to the bearing means. In order to convert the pivoting movement of the lever arms into a drive movement of the guided wheel, the coupling means of the force transmission train are arranged adjacently to the bearing means on the lever arms. This arrangement of the coupling means is preferably designed symmetrically with respect to the steering plane of symmetry. 
   It goes without saying that this variant of the invention is not necessarily tied to a “strict” L-shaped geometry of the two lever arms. It is also conceivable for the lever arms to have a curved design, the steering axes in each case being arranged symmetrically between the end portions of the curved lever arms, in order to convert the pivoting movement of the end portions provided at one end of the handles into a pivoting movement of the assigned other end portions. 
   Preferably, the guide means has a U-shaped downwardly bent crossmember which is arranged symmetrically with respect to the steering plane of symmetry. In this case, the two lever arms are articulated in the region of their pivot axes on the two legs of the crossmember which point downward in the direction of the drive means. 
   Since the force transmission train has no coupling portion performing between the first coupling means and the second coupling means, the force transmission train is fixed with a first end and a second end in relation to the crossmember in each case at a first fixing point and at a second fixing point. In this case, the fixing points are arranged opposite one another in relation to the bearing means of the lever arms. Preferably, the force transmission train is fixed with its first end to the fork and/or the steering shaft at the first fixing point between the lever arms and the drive means. Starting from this fixing point, the force transmission train extends via the first coupling element in the form of a first force deflection element to the drive means and in this case forms the first force transmission portion. The second end of the force transmission train is fixed to the steering shaft and/or to the crossmember at a second fixing point, the force transmission train extending from the second fixing point via the second force deflection element to a force transmission deflection element, fixed to the crossmember, and from there to the drive means. The force transmission train in this case forms the second force transmission portion between the second force deflection element and the drive means. 
   A preferred variant of this embodiment is distinguished in that the force transmission train is fixed releasably to the steering gear at the first and at the second fixing point. The ends of the force transmission train can be released from the steering gear by means of a respectively assigned changeover means and can be fixed to regions, running adjacently to the fixing points, of the force transmission portions of the force transmission train. Due to the release of the fixing of the ends of the force transmission train, the force transmission train runs in the form of a fixed loop around the coupling means designed as force deflection elements. A pivoting of the coupling means is therefore transmitted to the force transmission train in the ratio 1:1. By contrast, if the ends of the force transmission train are fixed at the fixing points, the pivoting of the coupling means results in only half as great a movement of the force transmission train, because the force deflection elements act as “loose” deflection elements in the same way as the loose pulleys of a block and tackle. Thus, by such a deflection means, a change in the step-up of the hand-operated drive device can be implemented in a simple way. 
   It is advantageous if a locking means of the handles is provided. The movement of the handles can thereby be blocked in a position in which the above-described release of the fixing points and the fastening of the released ends to the adjacently running regions are possible in a simple way. This applies correspondingly to the following variants of the drive means with a step-up change provided. 
   However, a locking means for blocking the handle movement is also advantageous entirely independently of the possibility of change in the step-up. It may be desirable to be able to block the movement of the handles. This applies to all the variants of the hand-operated drive device. 
   The bearing means of the two lever arms is preferably designed as a slot in the form of a long hole, arranged in the end portion of the first lever arm, and a guide bolt provided on the end portion of the second lever arm and arranged displaceably in the slot. A multiplicity of further variants for the design of the bearing means may be envisaged. It is in each case essential only that the bearing means brings about a symmetrical movement of the two handles. 
   The various embodiments of the hand-operated drive device which were described above can in each case be combined with a multiplicity of drive means for the guided wheel which are described below. 
   An advantageous first variant of such a drive means comprises a first torque transmission means provided on one side of a hub of the guided wheel and provided with a freewheel and, on the other side of the hub, a second torque transmission means provided with a freewheel. In this case, the force transmission train or an extension train fastened to the force transmission train so as to transmit tractive force runs from the first torque transmission means to the second torque transmission means by a change deflection element arranged on the steering gear. 
   The force transmission train is in this case guided in such a way that, during a movement of the train in a first direction, the first torque transmission means transmits a torque to the wheel in the driving direction of rotation and at the same time the second torque transmission means rotates freely in the freewheel direction of rotation. During the change in direction of movement of the force transmission train, the second torque transmission means correspondingly transmits a torque in the driving direction of rotation and the first torque transmission means rotates freely. 
   It is also conceivable that the two torque transmission means are mounted such that the two force transmission portions are arranged on the same side of the axis of rotation of the guided wheel. This may be required particularly when a disk brake means is already arranged on one of the two sides and therefore leaves little construction space for a torque transmission means. The change deflection element in such a case serves merely for guiding the force transmission train between the two torque transmission means. In this case, no “side change” of the force transmission train takes place between the two ends of the hub of the guided wheel. 
   The region of the force transmission train or of the extension train between the first and the second torque transmission means is designated below as the change portion. The force transmission train or the extension train is in each case connected operatively to the first and the second torque transmission means. In the region of the change portion, the force transmission train or the extension train is guided from the first to the second torque transmission means in such a way that a movement of the force transmission train in the first direction of movement gives rise to force transmission via the first torque transmission means to the guided wheel and at the same time to an actuation of the freewheel of the second torque transmission means opposite to the driving direction of the second torque transmission means. A reversal of the direction of movement of the force transmission train then correspondingly results in the fact that a drive force can be transmitted to the guided wheel by the second torque transmission means and at the same time the freewheel of the first torque transmission means is actuated. 
   The design of the torque transmission means depends on whether that active portion of the force transmission train which is connected operatively to the torque transmission means is designed as a rope, a chain or a toothed belt. If the active portion is designed as a chain, the assigned torque transmission means can in a simple way be designed as a chain wheel. 
   In a further variant, at least one torque transmission means is designed in the form of a rope drum element. These torque transmission means are arranged coaxially with respect to the axis of rotation of the wheel either on the two sides of the hub of the guided wheel or both on the same side of the guided wheel of the hub. The force transmission train or the extension train loops at least partially around the surface areas of the rope drum elements. Preferably, one rope drum element has on the surface area a spiral groove, the cross section of which is U-shaped, in which case the radius at the bottom of the U-shaped groove should be smaller than half the diameter of the force transmission train or extension train designed as a traction rope. 
   In this case, a mechanical clamping means may be provided, which ensures a tractive force-transmitting connection between the force transmission train or extension train and the rope drum element. If a mechanical clamping means is provided, it is located approximately in the middle of the rope drum element and the force transmission train or the extension train loops around the rope drum element with more than double the length with which the train is moved due to a maximum deflection of the handles. 
   If the materials of the train and of the rope drum elements are suitably selected in such a way that the frictional connection of the train to the rope drum element is ensured for all the tractive forces which occur, the use of a clamping means may even be dispensed with. 
   Regardless of whether the first or the second torque transmission means is designed in the form of a chain wheel or in the form of a rope drum element or as a combination of these two variants, it may be advantageous if these have diameters different from one another. The user of the device according to the invention can exert a greater force when the handles are pushed together than when they are drawn apart from one another because of the anatomy of the human body. In such a case, the different diameters of the torque transmission means ensure that, when the handles are drawn apart from one another, in spite of the lower force applied, a torque equal to that occurring when the handles are pushed together can be transmitted to the guided wheel. 
   A further advantageous variant of the device having this drive means provides for designing the force transmission train or the extension train, in the region of the change portion between the first and the second torque transmission means, at least partially to be elastically stretchable. It is thereby possible to provide the device according to the invention in steering gears, of which the extent along the steering axis is variable by a springing means. Springing means of this type are arranged, for example on bicycles, in a known way on forks, fork heads or the transition between the steering shaft and fore-part. 
   During the compression of such a springing means, the force transmission portions are necessarily shortened. The elasticity of the change portion is designed in such a way that the tractive force of the change portion can absorb the length of the force transmission portions which is released due to the compression of the springing means. In this case, the torque transmission means which is not acted upon by a drive force rotates in the freewheel direction. If no force is exerted on the steering handles, the two torque transmission means rotate in the freewheel direction, driven by the tractive force of the elastic change portion. During the rebound of the springing means, the force transmission portions of the force transmission train can assume their original length only by driving the front wheel in the direction of travel. The drive means thus acts at the same time as damping for the springing means, the oscillation energy being converted partially into the propulsion of the guided wheel. 
   The above statements apply similarly to situations where, additionally or alternatively to an at least partial elastic design of the force transmission train or of the extension train in the region of the change portion, the assigned change deflection element is arranged on the steering gear in such a way that it can be deflected elastically essentially along the direction of extent of the change portion. 
   In a further variant of the device having the above-described drive means, the first force transmission portion is guided with its end portion in each case adjacent to the extension train around a deflecting pulley and is fixed to the steering gear in the region between the deflecting pulley and change deflection element by a coupling means. The deflecting pulleys therefore ensure a tractive force-transmitting connection between the force transmission train and the assigned extension train in the function of loose pulleys. A step-up in the ratio 2:1 between the movement of the force transmission train and the movement of the extension train is thereby implemented. 
   It is particularly advantageous to design the coupling means and those regions of the force transmission portions which are adjacent to the coupling means in each case in such a way that the fixing of the force transmission train to the steering gear can be released and the end portion of the force transmission portion is arranged in the form of a loop around the assigned pulley. In this way, the functionality of the deflecting pulleys as “loose” pulleys can be canceled, so that a step-up ratio 1:1 with respect to the movements of the force transmission train and the extension train is achieved. 
   This variant is a variant for the provision of variable step-ups which is more cost-effective and simpler, as compared with hubs and chain shifts. It is nevertheless also conceivable to design the hubs of the guided wheel with chain or hub shifts in all the exemplary embodiments of the drive device which are described. 
   A further variant of the device provides a drive means in the form of a gearing means which is arranged at one end of the hub of the guided wheel and to which the first force transmission portion and the second force transmission portion of the force transmission train are coupled. This gearing means is designed in such a way that the alternating movement of the first and of the second force transmission portion which is induced by the alternating movement of the handles gives rise, for each direction of movement of the force transmission train, to torque transmission to the guided wheel. 
   A design variant of such a gearing means provides a first drive chain wheel arranged on the hub of the guided wheel and cooperates with the force transmission train and which has a freewheel opposite to the driving direction of the guided wheel. A first gearwheel is arranged, offset axially with respect to the first drive chain wheel, on the hub. This first gearwheel meshes with a second gearwheel arranged so as to be offset laterally with respect to the first gearwheel, the second gearwheel having a second drive chain wheel arranged so as to be spaced apart axially from it and coupled to the force transmission train. The force transmission train, which is designed in the region of the first and of the second chain wheel in the form of a chain, thus moves both the first and the second drive chain wheel in the same direction. When the force transmission train moves the first drive chain wheel in the driving direction, the second drive chain wheel runs in freewheel. When the force transmission train moves in the opposite direction, the first drive chain wheel runs in freewheel and the second drive chain wheel drives the assigned second gearwheel which, in turn, meshes with the first gearwheel. The rotational movement of the second drive chain wheel is thereby applied as propulsion to the guided wheel via the two assigned gearwheels. 
   As already presented above, the user of the hand-operated drive device applies different forces when the handles are pressed together and are drawn apart from one another. By suitable selection of the two gearwheels, a step-up convenient for the user can be set, so that, in spite of a lower force, an essentially identical torque is applied as propulsion to the guided wheel when the handles are drawn apart from one another. 
   A further variant of the drive device has, on the end portions, facing the guided wheel, of the first and of the second force transmission portion, a first and a second chain wheel which are in each case suspended on the chain wheel axis of rotation by means of a holding device. The drive means has a chain, cooperating with the two chain wheels, with two ends, which extends from its first end, fixed to the steering gear between the axis of rotation and the first chain wheel, via the first chain wheel around a drive chain wheel arranged on the axis of rotation and having a freewheel and back around the second chain wheel to the second end fixed to the steering gear between the axis of rotation and the second chain wheel. By the chain ends being fixed to the steering gear, the first and the second chain wheel function as “loose” pulleys. That is to say, a length change of the first and second force transmission portions coupled to the chain wheels is converted in the ratio 2:1 into a length change of the chain of the drive means, said chain cooperating with the chain wheels. 
   To change the step-up, it is particularly advantageous if the ends of the chain are fastened releasably to the steering gears, the chain ends having coupling means which allow a coupling to adjacent chain portions in such a way that the end portions of the chain in each case form a closed loop around the chain wheels. The function of the chain wheels as “loose” pulleys is thereby canceled. The step-up with respect to the length change of the force transmission train and of the chain of the drive means amounts in such a case to 1:1. 
   In the variant described above, force is applied to the guided wheel only in one direction of movement of the handles. It is therefore advantageous to provide a spring element which, in the opposite direction of movement of the handles, is compressed and therefore stores the force introduced. The latter is then released again during the opposite movement of the handles and is thus converted into the propulsion of the guided wheel. 
   The above-described variant of the drive means can also be implemented, instead of by chains and “loose” pulleys designed as chain wheels, by Bowden cables or toothed belts and loose pulleys in the form of rope pulleys or pinions for toothed belts. 
   A further variant of the hand-operated drive device according to the invention is characterized in that the guide means has a second force transmission train which is guided, essentially parallel to the first force transmission train and so as to be offset with respect to the latter, with specific assigned deflection elements between the coupling means and the drive means and is coupled to the first and to the second coupling means in such a way that the movement of the handles causes a movement, corresponding to the first force transmission train, of the second force transmission train. 
   If, as already presented above, torque transmission means are provided on the hub of the guided wheel, the first force transmission train cooperates for force transmission with the first torque transmission means and the second force transmission train cooperates for force transmission with the second torque transmission means. It is therefore no longer necessary in this case to provide a change deflection element in order to lead the force transmission train or an extension train coupled to the latter from the first torque transmission means to the second torque transmission means in a change portion. 
   It is possible to arrange the two torque transmission means both on one and the same side of the hub of the guided wheel and on its opposite sides symmetrically with respect to the steering plane of symmetry. 
   As already stated, it is possible to design the two torque transmission means provided on the hub of the guided wheel both as chain wheels and as rope drum elements or as belt pulleys. A combination of these variants with one another is also possible. 
   The above statements regarding a different diameter between the oppositely arranged torque transmission means apply correspondingly to the design variant having two parallel-guided force transmission trains. 
   All the variants of the various drive devices described can, of course, be combined with the different variants of the drive device, unless specified otherwise. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further advantages and features of the invention are explained in connection with the description of the following exemplary embodiments in the figures in which: 
       FIG. 1  shows a first variant of the hand-operated drive device according to the invention; 
       FIG. 2  shows the first variant according to  FIG. 1  in combination with a differently configured drive means; 
       FIG. 3  shows the first variant of the device according to  FIGS. 1 and 2  in combination with a second variant of a drive means; 
       FIG. 4  shows a second variant of the hand-operated drive device with two force transmission trains; 
       FIG. 5  shows a third variant of the hand-operated drive device with a drive means designed as a gearing means; 
       FIG. 6  shows the gearing means from  FIG. 5  in detail; 
       FIG. 7  shows a fourth variant of the hand-operated drive device; 
       FIG. 8  shows a fifth variant of the hand-operated drive device; 
       FIG. 9  shows a variant of the hand-operated drive device from  FIG. 8  in detail, and 
       FIG. 10  shows the first variant of the device according to  FIGS. 1 and 2  in combination with a third variant of a drive means. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1  shows a first embodiment of the device for hand-driven operation of a guided wheel R which is arranged on a steering gear  1  and which is pivotable about a steering axis L oriented perpendicularly with respect to the axis of rotation D of the guided wheel. A hand-operated drive device of this type is used particularly in a front wheel of a commercially available bicycle known from the prior art. In the pictorial illustration, therefore, for the sake of clarity, the remaining components of such a bicycle have not been shown, since these are in any case known from the prior art. 
   The guided wheel R with its axis of rotation D is arranged in a known way in a fork  10  of the steering gear  1  by means of a wheel hub N. The fork  10  has a fork head  101  which is designed symmetrically with respect to the axis of the steering shaft  11  which extends along the steering axis L upwardly, that is to say away from the guided wheel R. 
   A crossmember  12  oriented transversely with respect to the steering axis L is fastened to the steering shaft  11 , for example via a fore-part. In this first exemplary embodiment, this crossmember  12  is designed as a rectilinear tubular element. The crossmember  12  is arranged symmetrically with respect to a steering plane of symmetry in which the steering axis L lies and which is oriented perpendicularly with respect to the axis of rotation D of the guided wheel R. 
   A first handle  20  and a second handle  22  are arranged on the crossmember  12  on the right and left of the steering plane of symmetry. The handles  20 ,  22  extend essentially in the direction of travel of the guided wheel R and are angled slightly upward. 
   It goes without saying that other orientations of the handles are also possible. The handle position is normally selected such that a rider of the bicycle can conveniently exert force on the handles in order to move these parallel to the steering plane of symmetry. The handles are preferably in this case oriented mirror-symmetrically with respect to the steering plane of symmetry. 
   The first and the second handle  20 ,  22  have in each case a coupling means  21 ,  23  which fulfils various functions. On the one hand, the handles  20 ,  22  are coupled to the crossmember  12  via the assigned coupling means  21 ,  23 . For this purpose, the coupling means  21 ,  23  surround the crossmember  12  in such a way that a displacement of the handles along the axis of extent of the crossmember  12  is possible. On the other hand, the coupling means  21 ,  23  ensure the fixing of a force transmission train  3  via coupling points. As a result, a tractive force-transmitting connection between the force transmission train  3  and the coupling means  21 ,  23  and therefore indirectly also the handles  20 ,  22  is made. 
   The force transmission train  3  is produced at least partially, in particular, from a high-strength lightweight rope with a core consisting of preoriented polypropylene. 
   The coupling means  21 ,  23  cooperate as a guide means  2  with the crossmember  12  in order to ensure a movable mounting of the handles  20 ,  22 . 
   In the embodiment shown in  FIG. 1 , the crossmember  12  is designed as a tube of circular cross section. The coupling means  21 ,  23  in this case surround this tubular cross section in such a way that a displacement of the coupling means  21 ,  23  along the axis of extent of the crossmember  12  with low friction is possible. This displacement takes place along sliding portions  13 ,  14  which are arranged as portions of the crossmember symmetrically with respect to the steering plane of symmetry. 
   In order, in addition to the axial movement of the coupling means  21 ,  23 , to prevent a rotation of the coupling means  21 ,  23  about the axis of extent of the crossmember  12 , a guide rail  15  is arranged parallel to the crossmember  12 . The guide rail  15  is coupled rigidly to the crossmember  12  via two longitudinal struts fastened to the ends of the crossmember  12 . The guide rail  15  has in cross section a U-profile which is open in the direction of the crossmember  12 . Stabilizing means  200 ,  220  projecting into the guide rail  15  slide in each case in this U-profile from each coupling means  21 ,  23 . The stabilizing means  200 ,  220  thus, in cooperation with the guide rail, prevent a radial rotation of the coupling means  21 ,  23  or of the handles  20 ,  22  around the crossmember  12 . In order to ensure an easy sliding of the stabilizing means  200 ,  220  in the guide rail  15 , it is advantageous to design the stabilizing means  200 ,  220  with ball bearings. 
   The subassembly consisting of handles, coupling means and stabilizing means is produced in a weight-saving manner, in particular, from carbon fiber laminate. 
   It is, of course, conceivable to provide a guide rail  15  having a differently shaped cross section. It is essential merely that the stabilizing elements  200 ,  220  support the coupling means  21 ,  23  in the function of a supporting lever in such a way that a rotation of the coupling means  21 ,  23  is prevented. It would likewise be possible to dispense with a guide rail  15  if the cross-sectional geometry of the crossmember  12  per se prevents a rotation of the coupling means  21 ,  23  and of the handles  20 ,  22 . It would also be conceivable that stabilizing means engage in the direction of the crossmember into a guide groove formed in the crossmember. 
   Starting from the first coupling means  21  arranged on the left of the steering plane of symmetry in  FIG. 1 , the force transmission train  3  extends, parallel to the direction of extent of the crossmember  12 , to the first end, arranged on the left of the steering plane of symmetry, of the crossmember  12 . A force transmission deflection element  36  in the form of a deflecting pulley is provided there. This deflecting pulley is arranged on the first longitudinal strut in such a way that the force transmission train  3  coming from the coupling point of the first coupling means  21  is deflected through essentially 180°. The force transmission train therefore runs back again, past the first coupling means  21 , to a first force deflection element  37  likewise designed as a deflecting pulley. This force deflection element  37  is fixed, next to the first sliding portion  13  of the crossmember  12 , to said crossmember  12 . This deflection element  37  changes the direction of extent of the force transmission train  3  essentially through 90° and deflects the train  3  in the direction of the hub of the guided wheel R. 
   Starting from the coupling point of the first coupling means  21 , the force transmission train  3  runs in the other direction likewise essentially parallel to the direction of extent of the crossmember  12 , past the second coupling means  23 , to the second end of the crossmember  12  having the second longitudinal strut. A coupling deflection element  35  in the form of a deflecting pulley is mounted symmetrically with respect to the steering plane of symmetry on this second longitudinal strut. This deflection element  35 , in turn, changes the direction of extent of the force transmission train  3  essentially through 180°, so that the latter passes back to the second coupling means  23 . At the coupling means  23 , the nonpositive connection between the force transmission train  3  and the second coupling means  23  is ensured by a coupling point. The force transmission train  3  is then led further on in the direction of the steering plane of symmetry to a second force deflection element  38 . This second force deflection element  38  is likewise designed in the form of a deflecting pulley and is fastened to the crossmember symmetrically with respect to the steering plane of symmetry in relation to the first force deflection element  37 . This second deflecting pulley  37 , too, deflects the force transmission train  3  essentially through 90° in the direction of the hub of the guided wheel R. 
   Since the force transmission train  3  extends in a coupling portion  32 , via the coupling deflection element  35 , from the coupling point of the first coupling means  21  to the coupling point of the second coupling means  23 , there is a nonpositive connection between the two handles  20 ,  22 . This nonpositive connection in a simple way brings about a movement, symmetrical with respect to the steering plane of symmetry, of the two handles  20 ,  22  along the two sliding portions  13  and  14 . 
   From the coupling point of the first coupling means  21 , the force transmission train  3 , on its way via the force transmission deflection element  36  and the first force deflection element  37  as far as the drive means  4  arranged in the region of the hub of the guided wheel R, forms a first force transmission portion  30 . 
   Correspondingly, the force transmission train  3 , on its way from the coupling point of the second coupling means  23  via the first force deflection element  37  as far as the drive means  4  arranged in the region of the hub of the guided wheel R, forms a second force transmission portion  31 . 
   The positive coupling implemented via the coupling portion  32  of the force transmission train  3  ensures a symmetrical movement of the two handles  20 ,  22  with respect to the steering plane of symmetry when these are moved apart from one another. The positive coupling implemented by the nonpositive coupling of the two force transmission portions  30 ,  31  leads correspondingly to the symmetrical movement of the handles  20 ,  22  when these are pressed together. In this case, the length change of the first force transmission portion  30  induced in each case by these handle movements is accompanied by an opposite length change of identical amount of the second force transmission portion  31 . 
   The first and the second force transmission portion  30 ,  31  run in each case partially as a link chain in the region of the drive means  4 . As a result, the force transmission train  3  cooperates with first and second torque transmission means  40 ,  41  designed as drive chain wheels. The first drive chain wheel  40  is in this case on one side of the hub N of the guided wheel R, and the second drive chain wheel  41  is in a symmetrical arrangement on the opposite wheel side. Each of the two drive chain wheels  40 ,  41  has, opposite to the driving direction of the guided wheel, a freewheel on the axis of rotation D of the hub N. 
   The force transmission train  3  runs with its two chain portions around the two drive chain wheels  40 ,  41  and up to the fork head  101 . Along this path, the force transmission train  3  is again designed as a train portion. At the fork head  101 , a change deflection element  39  in the form of a deflecting pulley deflecting the force transmission train  3  is arranged. The change deflection element  39  deflects the force transmission train from that flank of the first drive chain wheel  40  which is oriented forward in the direction of travel to that flank of the second drive chain wheel  41  which is oriented forward in the direction of travel. The portion of the force transmission train between these two flanks of the drive chain wheels  40 ,  41  is designated as a change portion  33 . 
   The change from one torque transmission means to the other takes place in such a way that, during a movement of the force transmission train  3 , one of the two drive chain wheels  40 ,  41  is moved in the driving direction of rotation of the wheel R and the other drive chain wheel in each case is moved in the freewheel direction. 
     FIG. 2  shows essentially the first variant of the hand-operated drive device according to  FIG. 1  in combination with a differently configured drive means  4 . Identical reference symbols are therefore used for the same structural elements. Reference is made to the preceding description in so far as there is no different design. 
   The only difference from the hand-operated drive device of  FIG. 1  is that the force deflection elements  37 ,  38  are arranged in such a way that the first force transmission portion  30  runs partially parallel and adjacently to the second force transmission portion  31 , that is to say, before the two force transmission portions are deflected toward the wheel R, they run through the steering plane of symmetry, in contrast to  FIG. 1 . It is clear that the arrangement of the force deflection elements  37 ,  38  depends on the design of the drive means  4  and on the geometry of the fork  10 . A multiplicity of fork variants are known from the bicycle sector and in each case necessitate different drive means  4  with different geometries in terms of the guidance of the force deflection train  3 . 
   The drive means  4  according to  FIG. 2  is designed symmetrically with respect to the steering plane of symmetry in the same way as the drive means described above. The first force transmission portion  30  runs in the direction of the hub N of the wheel R and in this case forms a loop around a deflecting pulley  47 , the end of the first force transmission portion  30  being fixed to the fork head  101  by a coupling means  300 . The axis of rotation of the deflecting pulley is arranged essentially parallel to the axis of rotation D of the guided wheel and is connected to an extension train  3 ′ via a yoke so as to transmit tractive force. 
   This extension train  3 ′ runs first with a first chain portion around a first drive chain wheel  40  designed as illustrated in  FIG. 1 . Thereafter, the extension train  3 ′ is deflected from the first side of the wheel R to its second side by means of a change deflection element  39  according to  FIG. 1 . In this case, the extension train  3 ′ forms the change portion  33  of the force transmission train  3 . 
   The first and the second deflecting pulley act in each case as loose pulleys in such a way that the length change of one of the two force transmission portions  30 ,  31  is transferred, halved, to the extension train  3 ′. A step-up in force transmission between the handles and the axis of rotation D of the guided wheel R is consequently achieved in a simple way. 
   The two coupling means  300 ,  301  allow a release of the first and second force transmission portions  30 ,  31  fixed in each case and a coupling of the free ends to adjacently guided regions of the respective force transmission portion  30 ,  31 , in such a way that the functionality of the deflecting pulleys  47 ,  48  as loose pulleys is canceled. Force transmission then takes place in the ratio 1:1. For this purpose, at the adjacent regions of the respective force transmission portions  30 ,  31 , couplers are provided which allow a connection to the ends of the force transmission portions  30 ,  31 . These couplers preferably act purely mechanically, for example by means of a plug and/or latch mechanism. 
     FIG. 3  shows the first variant of the hand-operated drive device according to  FIGS. 1 and 2  in combination with a second variant of a drive means. 
   In a similar way to the drive device  4  according to  FIG. 2 , the first and the second force transmission portion  30 ,  31  are coupled in each case to a loose chain wheel  49 ,  49 ′. In this case, however, the two force transmission portions  30 ,  31  are coupled to the axes of rotation of the two chain wheels  49 ,  491  in each case via a holding yoke. The two chain wheels  49 ,  491  are arranged on one side of the wheel R. This means that the two force deflecting pulleys  37 ,  38  are arranged on one side of the steering plane of symmetry and therefore not symmetrically on the crossmember  12 . 
   The two chain wheels  49 ,  49 ′ are connected operatively in each case to an extension train in the form of a link chain  44 . The first and the second end  45 ,  46  of the chain  44  are fastened in each case to the fork  10  between the chain wheels  49 ,  49 ′ and the hub N of the wheel R by coupling means  450 ,  450 ′. Starting from the coupling means  450 ,  450 ′, the first end  45  of the chain  44  runs essentially parallel to the second end  46  in the direction of the chain wheels  49 ,  49 ′. The two chain wheels are held one behind the other in the direction of travel and parallel to the steering plane of symmetry by the force transmission portions  30 ,  31 . 
   The two chain ends  45 ,  46  loop around the first and the second chain wheel  49 ,  49 ′ and then run downward to the hub N of the wheel R. The two chain ends  45 ,  46  converge there around a drive chain wheel  46 . The drive chain wheel  46  is arranged on the hub N with a freewheel correspondingly to the drive means from  FIGS. 1 and 2 . 
   In this embodiment of the drive means  4 , force is transmitted in the propulsion direction of the wheel R when the handles  20 ,  22  are either drawn apart from one another or are pressed together. The crossmember  12  may have provided on or in it a spring device which is tensioned as a result of the movement of the handles  20 ,  22 , during which no force is applied to the wheel R in the propulsion direction. This force is then released again in the propulsion direction during the handle movement. 
   In a similar way to  FIG. 2 , the first and the second chain wheel  49 ,  49 ′ act in each case as loose pulleys, thus leading to a force step-up in the ratio 2:1. The coupling means  450 ,  450 ′ in each case allow the release of the chain ends  45 ,  46  from the fork and the coupling of the ends  45 ,  46  to chain regions running adjacently to these, in such a way that force transmission takes place in the ratio 1:1. 
     FIG. 4  shows a second variant of the hand-operated drive device with two force transmission trains  3 ,  3 ″. 
   A second force transmission train  3 ″ is provided, parallel to the first force transmission train  3 , via parallel-arranged coupling deflection elements  36 ,  36 ′ and force transmission deflection elements  35 ,  35 ′. Correspondingly, twice as many force deflection elements are provided, in such a way as to deflect the first force transmission train  3  and the second force transmission train  3 ″ in each case with its first and second force transmission portions  30 ,  31 ,  30 ′,  31 ′ in the direction of a drive means  4  provided in the region of the hub N of the wheel R. The force transmission portions  30 ,  31 ,  30 ′,  31 ′ can cooperate there in each case with an assigned torque transmission means. 
   In this variant, there is no need to deflect the single force transmission train or an extension train coupled to it from the first to the second torque transmission means by a change deflection element  39 , as shown in  FIGS. 1 and 2 . 
     FIG. 5  shows a third variant of the hand-operated drive device with a drive means  4  designed as a gearing means. 
   Contrary to the previous hand-operated drive devices, the guide means  2  of this variant is designed in such a way that the handles  20 ,  22  are arranged at the ends of two lever arms  24 ,  25 . The lever arms  24 ,  25  are articulated in the region of the fork head  101  and their pivot axes  240 ,  250  are arranged symmetrically with respect to the steering plane of symmetry. They extend essentially rectilinearly from the pivot axes  240 ,  250  to the handles  20 ,  22 . A symmetrical movement of the handles  20 ,  22  which has guide paths in the form of a segment of a circle is thereby predetermined. 
   The two coupling means  21 ,  23  are provided adjacently to the handles on the levers  24 ,  25 . The run of the force transmission train  3  and the arrangement of the deflection elements  35 ,  36 ,  37 ,  38  correspond essentially to those of the devices in  FIGS. 1 and 2 , the axes of rotation of the coupling deflection element  35  and of the force transmission deflection element  36  being oriented essentially parallel to the steering axis L. It is thereby possible to arrange the lever arms  24 ,  25  in such a way that, during their symmetrical pivoting movement, they run between the force transmission train which runs back and forth. 
   The coupling means  21 ,  23  are designed here in such a way that the coupling point of the force transmission train  3  can slip along the direction of extent of the respective lever arms  24 ,  25  in order to compensate the curvature of the guide paths, in the form of a segment of a circle, of the handles  20 ,  21 . This results in essentially rectilinearly formed drive paths of the coupling points of the force transmission train  3 . 
   The first and the second force transmission train  30 ,  31  are deflected onto the same side of the wheel R by the force deflection elements  37 ,  38 . The two portions  30 ,  31  are connected operatively there to a drive means  4  in the form of a freewheel gearing. 
   The freewheel gearing  4  is illustrated in detail in  FIG. 6 . For the sake of clarity, the illustration of a gearing housing for encasing and fastening the gearing to the hub N of the wheel R has been dispensed with. 
   The first force transmission portion  30  runs in the form of a link chain portion to a first chain wheel  42  arranged on the hub N. The first chain wheel  42  has a freewheel opposite to the driving direction of rotation of the wheel R. A second chain wheel  43  with an essentially parallel axis of rotation is provided, spaced apart radially from the first chain wheel  42 . This second chain wheel  43  likewise has a freewheel, but this is oriented opposite to that of the first chain wheel  42 . 
   The first force transmission portion  30  runs around the first chain wheel  42  to the second chain wheel  43  and consequently merges into the second force transmission portion  31 . A first and a second gearwheel  42 ′ and  43 ′ are provided, in each case spaced apart axially from the two chain wheels  42 ,  43 . In the driving direction of the chain wheels  42 ,  43 , these corotate the assigned gearwheels  42 ′,  43 ′ in the same direction. Opposite to the driving direction, the chain wheels and gearwheels run in each case freely with respect to one another. The gearwheels are arranged in such a way that the first gearwheel  43 ′ meshes with the second gearwheel  42 ′. If, then, the force transmission train  3  moves clockwise, force is applied to the wheel R via the first chain wheel  42 ′. The second chain wheel  43  runs in freewheel. Counterclockwise, the first chain wheel  42  runs in freewheel and the second chain wheel  43  drives the second gearwheel  43 ′ which, in turn, meshes with the first gearwheel  42 ′. The first gearwheel  42 , is in this case driven in the propulsion direction of rotation of the wheel R and transmits force to the wheel R. 
   As illustrated in  FIG. 6 , desired force step-ups can be implemented by the selection of different diameters of the chain wheels  42 ,  43  and/or of the gearwheels  42 ′,  43 ′. This takes into account the fact that a user can normally apply a lower force when the handles are drawn apart from one another than when they are pressed together. 
     FIG. 7  shows a fourth variant of the hand-operated drive device with a further variant of a drive means. 
   This hand-operated drive device corresponds essentially to the illustration from  FIG. 5 . The only difference is that the ends of the crossmember  12  run, bent downward toward the wheel, symmetrically with respect to the steering plane of symmetry. 
   The drive means  4  corresponds in terms of the operative principle and the construction geometry to the drive means shown in  FIG. 1 . The torque transmission means, however, are designed as rope drum elements  40 ,  41 . The advantage of this is that the mass of drive chains in the overall mass of the parts with an alternating direction of movement is saved, and that the force transmission chain  3  can be designed continuously in the form of a rope. 
     FIG. 8  shows a fifth variant of the hand-operated drive device in combination with the drive means  4  from  FIG. 1 . 
   As in the embodiment according to  FIG. 7 , the crossmember  12  is bent downward. However, the guide means  2  is designed differently. The handles  20 ,  22  are arranged at the end of two lever arms  24 ,  25 . These lever arms  24 ,  25 , however, are shaped as angle elements. Each angle element  24 ,  25  extends with one leg outward transversely with respect to the steering plane of symmetry and then bends upward in an angular portion. The bend angle is in this case almost 90°. 
   The handles  20 ,  22  are arranged symmetrically with respect to the steering plane of symmetry at those ends of the levers  24 ,  25  which face away from the steering plane of symmetry. The other end portions are coupled to one another in the region of the steering plane of symmetry via a bearing means  26 , in such a way that the levers can be moved symmetrically with respect to the steering plane of symmetry about the pivot axes  240 ,  250  arranged in the angular region of the levers and coupled to the crossmember  12 . The bearing means  26  comprises a rectilinearly designed slot arranged in the first lever  24  and a bearing bolt arranged on the second lever arm  25  and engaging into the slot. During the symmetrical movement of the handles  20 ,  22 , the bearing bolt moves back and forth between the two end portions of the slot. 
   The first and the second coupling means  21 ,  23  for coupling a force transmission train  3  are provided adjacently to the bearing means  26 . The two coupling means  21 ,  23  are designed in the form of deflecting pulleys. The first end of the force transmission train  3  is fastened below the first coupling means  21  to the steering gear  1 , here to the steering shaft  11 , at a fixing point  340 . The force transmission train  3  extends from there in the first force transmission portion  30  around the first coupling means  21  to the drive means  4 . 
   The second end of the force transmission train  3  is fastened above the second coupling means  23  to the crossmember  12  at a fixing point  340 ′. It loops from there around the second coupling means and runs upward again as far as a force transmission deflection element  36  arranged in the region of the bending point of the crossmember  12  and taking the form of a deflecting pulley. This deflecting pulley deflects the force transmission train  3  essentially through 180° downward in the direction of the drive means  4 . In this case, it is essential that the force transmission deflection element  36  is arranged above the fixing point  340 ′ of the second end of the force transmission train  3 . 
   This arrangement ensures that, during the pivoting movement of the handles  20 ,  22 , the coupling means  21 ,  23  move up and down symmetrically with respect to the axis of symmetry and shorten or lengthen the first and the second force transmission portion  30 ,  31  in opposition, so that the force can consequently be transmitted to the drive means. 
   The two coupling means  21 ,  23  acting as deflecting pulleys in this case function as loose pulleys which cause force transmission in the ratio 2:1. A change in the force transmission to the ratio 1:1 can be achieved by the function of the loose pulleys being canceled. A modification, suitable for this purpose, of the hand-operated drive device from  FIG. 8  is illustrated, somewhat enlarged, in  FIG. 9 . 
   The first and the second fixing point  340 ,  340 ′ and those portions of the first and second force transmission portion  30 ,  31  which are adjacent to these points are for this purpose designed with coupling elements. These allow the release of the fixing to the steering gear  1 , that is to say to the crossmember  12  or to the steering shaft  11 , and mechanical cooperation such that the first and the second coupling means  21 ,  23  in the form of deflecting pulleys no longer act as loose pulleys. 
     FIG. 10  shows the first variant of the hand-operated drive device according to  FIG. 3  in combination with a third variant of a drive means. Identical reference symbols again designate the same structural elements. Once again, the guide rail  15  is not illustrated for the sake of clarity. 
   The first and the second force transmission portion  30 ,  31  lead to a first and a second torque transmission means  40 ,  41 . In contrast to the embodiments described above, the torque transmission means are both arranged on the same side of the guided wheel R. Moreover, they are not positioned on the axis of rotation D of the guided wheel R, but in the region between the change deflection element  39  and the hub N. For this purpose, the fork  10  has a holding means  451 . An intermediate shaft  453  is mounted rotatably about an axis  452  on this holding means  451 . The axis  452  is arranged essentially parallel to the axis of rotation D of the guided wheel. The two torque transmission means in the form of two rope drums  40 ,  41  are arranged rotatably on the intermediate shaft  453 . The two rope drums  40 ,  41  have, opposite to the driving direction of rotation of the wheel R, a freewheel with respect to the intermediate shaft  453 . A chain wheel assembly  454 , such as is known from bicycle chain shifts, is arranged adjacently to the two rope drums  40 ,  41  on the intermediate shaft  453 . During rotation in the driving direction of rotation, the rope drums  40 ,  41  in each case drive the chain wheel assembly  454  in driving rotation. 
   The force transmission train  3  is guided between the first rope drum  40  and the second rope drum  41  with a change deflection element  39 , fastened to the fork head  101 , in a change portion  33 . As shown in  FIGS. 1 ,  2  and  7 - 9 , the guidance of the change portion  33  takes place such that the first rope drum  40  rotates in freewheel when the second rope drum  41  rotates in the wheel driving direction, and vice versa. 
   The rotation of the chain wheels of the chain wheel assembly  454  can be transmitted by means of a drive chain  456  which is connected operatively to the chain wheel assembly  454  and to a drive chain wheel  46  arranged on the hub N. For changing the drive chain  456  between the chain wheels of different size of the chain wheel assembly  454 , an overthrow, not illustrated in  FIG. 10 , is provided. Such an overthrow corresponds essentially to the overthrows, known from bicycle technology, for the front chain leaves. So that the drive chain  456  has sufficient tension for all the chain wheels of the chain wheel assembly  454 , a tension chain wheel  455  is provided, which deflects the drive chain  456  between the chain wheel assembly  454  and the drive chain wheel  46  triangularly. For this purpose, the tension chain wheel  455  may be designed as a spring arm articulated with a spring means on the holding means  451 . 
   The above-described variant of the drive means affords the advantage, in particular, that it can be combined with a bicycle which uses disk brake systems, and that a chain wheel assembly for a chain shift of the drive means  4  is not operated with an alternating rotational movement. This variant is also suitable for a bicycle fork  10  designed resiliently between the holding means  451  and hub N, because the tension chain wheel  455  compensates the compression travel. If the spring device of the fork is arranged above the holding means  451 , the change portion  33  and/or the change deflection element  39  may be designed elastically in such a way that the compression movement is compensated. 
   All the above-described variants of the drive means can be combined with hubs N of the guided wheel R which in each case have a commercially available hub shift. 
   It goes without saying that all the above-described variants of the hand-operated drive device can be combined with the different variants of the drive means. For this purpose, in each individual case, it is necessary to orient the force deflection elements  37 ,  38  differently or to provide additional deflection elements in the first and/or the second force transmission portion  30 ,  31 . 
   LIST OF REFERENCE SYMBOLS 
   
       
         1  Steering gear 
         10  Fork 
         101  Fork head 
         11  Steering shaft 
         12  Crossmember 
         13  Sliding portion 
         14  Sliding portion 
         15  Guide rail 
         2  Guide means 
         20  First handle 
         200  Stabilizing element 
         21  First coupling means 
         22  Second handle 
         220  Stabilizing element 
         23  Second coupling means 
         24  First lever arm 
         240  Pivot axis of first lever arm 
         25  Second lever arm 
         250  Pivot axis of second lever arm 
         26  Bearing means 
         260  Slot 
         261  Guide bolt 
         3  Force transmission train 
         3 ′ Extension train 
         3 ″ Second force transmission train 
         30  First force transmission portion 
         300  Coupling means 
         31  Second force transmission portion 
         310  Coupling means 
         32  Coupling portion 
         33  Change portion 
         34  First end of the force transmission train 
         340  Fixing point of the first end 
         34 ′ Second end of the force transmission train 
         340 ′ Fixing point of the second end 
         35  Coupling deflection element 
         36  Force transmission deflection element 
         37  First force deflection element 
         38  Second force deflection element 
         39  Change deflection element 
         4  Drive means 
         40  First torque transmission means 
         41  Second torque transmission means 
         42  First chain wheel 
         42 ′ First gearwheel 
         43  Second chain wheel 
         43 ′ Second gearwheel 
         44  Chain 
         45  First end of the chain 
         450  Coupling means 
         45 ′ Second end of the chain 
         450 ′ Coupling means 
         46  Drive chain wheel 
         47  Deflecting pulley 
         48  Deflecting pulley 
         49  Chain wheel 
         49 ′ Chain wheel 
         451  Holding means 
         452  Axis 
         453  Intermediate shaft 
         454  Chain wheel assembly 
         455  Tension chain wheel 
         456  Drive chain 
       R Guided wheel 
       D Axis of rotation of the guided wheel 
       N Hub of the guided wheel 
       L Steering axis