Abstract:
The invention relates to a bicycle ( 100 ) having a frame structure ( 200 ) that comprises a swingarm structure ( 225 ) including a first substantially U-shaped sheet metal part for holding a wheel ( 103 ), the frame structure further comprising a frame bridge ( 219 ) consisting of a second substantially U-shaped sheet metal part. The first U-shaped sheet metal part is bent substantially in a first bending plane (P) to form a first U-shape, and the second U-shaped sheet metal part is bent in a second bending plane (Q) to form substantially a second U-shape. The first bending plane extends substantially perpendicular to the second bending plane.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    Field of the Invention 
         [0002]    The present invention relates to a bicycle with an electric drive, as well as to a frame structure for the same. 
         [0003]    Discussion of Related Art 
         [0004]    WO 2013/117643 of the same applicant was published for the first time in 2013 and discloses a drive for bicycles. It comprises a central housing, on which lateral rockers for supporting a wheel may be positioned. The central housing may house a motor, a gear and/or further components. 
         [0005]    EP 2 230 164 by Thomus Veloshop has been published for the first time in 2010 and discloses a bicycle frame, in which a battery unit, which is adapted for an auxiliary drive, may be housed in the lower tube. The lower tube is provided, to this end, with a closable opening, through which a battery unit may be readily introduced into or removed from the tube segment. In the bicycle of said publication, the drive motor is integrated in the rear wheel. 
         [0006]    EP 1 188 659 by Honda Motor Co. Ltd., has been published for the first time in 2002 and discloses a dismountable bicycle with an auxiliary drive. The hub of the rear wheel is attached on both sides to a two-part rear portion of the frame structure. These two parts are connected to each other by means of screws. The rear part of the frame structure is removably connected to the anterior frame structure by means of a sort of hinge. The saddle bar is directly attached to the rear part of the frame structure by means of clamping, wherein no conventional saddle bar is provided. The battery unit is attached between both parts of the rear frame structure, whereas the other components of the drive are arranged underneath the same. 
       SUMMARY OF THE INVENTION 
       [0007]    The object of the invention is to provide a bicycle, which is suitable for an electric drive, as well as a frame structure for the same. 
         [0008]    In one aspect of the invention, a frame structure (frame box) is provided, which has a particularly robust, torsion-resistant but nonetheless light construction. Moreover, the frame structure is provided with a relatively simple construction, with low production costs. A further advantage lies in the fact that the frame structure is suitable for different vehicles. 
         [0009]    In one aspect of the invention the drive components and the energy supply are arranged inside the frame structure and therefore form a compact unit with a low center of gravity. The frame structure protects the components from external agents. Since the frame structure is at least partially formed of thermal conductive material, it may also operate as a cooling body. 
         [0010]    Fields where the invention may be used are robust velocipedes for rent with and without an electric drive, for example, bicycles for transporting loads, bicycles with more than two wheels (tricycles), etc. The frame structure according to the invention may also be adapted for different applications. It is possible, for example, to use the frame structure in lightweight vehicles, which are particularly suitable for short range transport. It is also possible to construct vehicles with four or more wheels. 
         [0011]    In an embodiment, the frame structure is provided with two substantially U-shaped sheet metal parts. A first area comprises a swingarm structure with two rockers, which are connected to each other frontally by a web (shoulder). The rockers may for example be formed by a bent U-shaped metal sheet, which forms a wheel compartment for partially housing and supporting a wheel. A second area comprises a frame bridge made of substantially U-shaped metal sheet, which encloses a relatively large volume, therefore forming a housing for a drive (drive box), in which, if necessary, the components for transmitting a driving torque and other components, too, such as a controller, may be provided, for example. In order to increase the stability, the sheet edges of the swingarm structure and the frame bridge may be at least partially folded. 
         [0012]    As an alternative, or additionally, the drive box may be used for housing an internal bearing (pedal bearing) for a pedal bearing axle and a chain ring or a pulley. Similarly, it is possible that such a drive box houses an electric drive or another type of motor. 
         [0013]    In a variant of the frame structure the leg ends of the U-shape of the frame bridge are solidly mechanically connected to the shoulder of the U-shape of the swingarm structure, so that the bending axles of the swingarm structure and the frame bridge are substantially perpendicular to each other. If necessary, specially formed brackets may be arranged on the leg ends of the swingarm structure, for supporting a wheel or a wheel hub. These brackets allow an encapsulated arrangement of the drive without the need for dividing a possible drive chain. Furthermore, in this way, a drive belt may be provided. 
         [0014]    A further advantage of the frame structure, with respect to frame structures known in the state of the art, is that the geometry of the swingarm structure does not directly depend on the geometry of the drive box. In this way, by using only one type of swingarm structure, it is possible to construct different types of frame structures for different vehicles, by means of differently shaped frame bridges. 
         [0015]    According to the invention, a bicycle with a frame structure may be provided with a swingarm structure made of a first substantially U-shaped metal sheet part for housing a wheel, as well as a frame bridge provided by a second substantially U-shaped metal sheet part. It is envisaged that the first U-shaped metal sheet part is substantially bent in a first bending plane to form a first U-shape, and the second U-shaped metal sheet part is bent in a second bending plane to form a second U-shape. The first bending plane according to the invention is substantially perpendicularly arranged with respect to the second bending plane, as explained in the following. The first bending plane may be considered a plane, which is substantially perpendicular to the bending axis or bending axes of the first substantially U-shaped metal sheet part. The second bending plane may be considered a plane, which is substantially perpendicular to the bending axis or bending axes of the second substantially U-shaped metal sheet part. The first U-shaped metal sheet part and the second U-shaped metal sheet part are provided with a first leg with a first leg end and a second leg with a second leg end, respectively, as well as a shoulder area. According to the invention, the first and the second leg end of the second U-shaped metal sheet part may be mechanically connected to the shoulder area of the first U-shaped metal sheet part. 
         [0016]    The frame bridge may comprise a supporting structure, which extends between both legs of the frame bridge and operatively connect these to each other and may also be used for supporting a drive component. The supporting structure may be provided with at least a cavity for housing a drive component. The supporting structure may be a plate structure, for example. Such a plate structure may comprise one or more plates. In this way, the supporting structure may, if necessary, be readily mechanically reinforced, at least partially, as explained in the following. An improvement of the structural mechanical properties may be achieved, if at least one edge of the swingarm structure and/or at least one edge of the frame bridge is at least partially inwardly and/or outwardly folded. The frame bridge may have openings for attaching other frame parts and/or a stand and/or may be provided as a cooling air inlet. 
         [0017]    The first and the second end of the swingarm structure may be provided, respectively, with a housing means for supporting a wheel axle. These bracket-shaped preferably protrude from the rockers, may therefore be considered as brackets. The housing means may also comprise drop-outs. 
         [0018]    A particularly simple mounting of a rear wheel, or a rapid replacement of the same, may be obtained, if the housing means are provided with mounting elements, which are adjustable with respect to the rockers. In a variant of such embodiments, the mounting means may be adjustably provided on brackets, which are fixed to the rockers, as explained in the following. In a variant, it is possible to use adjustment screws to change the orientation (for example the distance) of the mounting means with respect to the pedal bearing shaft. The adjustment screws may be slidably positioned, to this end, in oblong openings. In this way, the distance between a wheel axle supported by the housing means and the pedal bearing shaft may be increased or reduced, so that the tension of a drive chain or drive belt may adjusted, for example. In this way, it is possible to possibly omit an additional chain or belt tensioning device. The mounting elements may be provided with drop-outs. 
         [0019]    In a variant of the frame structure, the mounting elements may be separated from the rockers, so that it may be possible to use different mounting elements for different types of rear wheels, for example. In such a variant it is therefore possible to arrange interfaces on the brackets for receiving different mounting elements. 
         [0020]    In principle, a frame structure according to the invention may be produced in a single metal sheet piece. In most cases it is however advantageous, if the frame structure is composed of different parts. The individual parts may be preferably made of aluminum or aluminum alloys or steel. Hybrid constructions with different materials for different parts of a frame structure according to the invention may also be considered. 
         [0021]    In a frame structure according to the invention it is possible to use different interchangeable lateral outer covers, and therefore isolate the drive box from the outside. In this way, the drive components contained inside the drive box may be protected against vandalism, humidity and dust. If the metal sheet edges of the swingarm structures are folded, it is possible through such external covers for both rockers, to define respective compartments joined with the drive box and encapsulate the same from the outside. These are suitable for housing a battery, for example, or a drive train or a drive belt or other elements. The covers may be used for cooling the inner elements. 
         [0022]    The outer covers may be provided in one or more parts and may be made of metal, for example, or transparent or opaque extruded plastic or fiber-reinforced plastic material. The covers may be part of the supporting structure. At the rear end of the rockers, additional covering elements (hinge elements, cover metal sheets, for example) may be arranged, which have to provide additional protection against vandalism, for example, for the brake system (brake disc). These cover elements may also be elements for a specific deviation of air flowing around the bicycle, and therefore for example for cooling the braking system during operation. 
         [0023]    The frame structure may be provided with additional fixing points for attaching additional components. For example, in the area of the leg ends of the wing structure, attachment points for a luggage support may be provided. 
         [0024]    By using materials (aluminum, for example) with a good thermal conductivity, the frame structure may also be used for discharging heat, which is produced by components inside the frame structure, such as the drive motor, a battery, a component of the drive controller or a brake. To this end, the frame structure may, if necessary, be provided with additional elements for increasing convection, such as cooling ribs or cooling channels. 
         [0025]    Depending on the embodiment and the application area, the individual parts of the frame structure are glued, welded, riveted and/or screwed to each other. 
         [0026]    By using metal sheet parts, contrary to the frame structures of the state of the art which are composed of tubes, the frame structures according to the invention may be easily welded by robots. In this way, frame structures may be produced with high precision and a high reproducibility in a very cost effective way. 
         [0027]    An advantage of the frame structure according to the invention is the fact that massive components, such as the battery, may be positioned at a relatively short distance from the road surface. In this way, the general center of mass of a bicycle built on the frame structure according to the invention lies at a relatively short distance from the road. Such a bicycle has a good maneuverability and a particularly stable position, without easily tipping over. Corresponding bicycles also have good driving characteristics. 
         [0028]    A variant of the inventions envisages the use of an active cooling system for batteries and/or motor and/or brakes. This system may include a fan and/or a Peltier element and/or a cooling circuit. Such an active cooling system may ensure an improved cooling of battery, electronics and motor during driving and/or a charging cycle. Such a system may also include cooling channels, which extend along the frame structure inside the same, and which allow a flow through the frame structure between one or multiple cooling air inlets and outlets. Such systems may in particular be used in hot climates. 
         [0029]    In addition or as an alternative, according to the invention, systems for active heating of batteries or other components may also be provided inside a frame structure, in order to ensure optimal charging cycles of batteries during winter time or in cool climates. As an alternative to such active heating systems, or as a supporting means for the same, portions of the frame structure may also be provided with a thermal insulation. 
         [0030]    As an alternative or as an addition, at least one of the two rockers of the frame structure may have a compartment, which may be opened, for example, for removing a cover or for opening a door. This allows, for example, the removal or replacement of batteries. Alternatively or additionally, in this way, access to an energy or data interface may be provided, for example. Such a folding mechanism may also be used for improved cooling of batteries, for example, when the bicycle is stationary. The locking and unlocking and the opening or closing may be manually or automatically performed. 
         [0031]    In a further aspect of the invention a handlebar for a bicycle is provided, which is ideally suited for combination with the frame structure, although it may also be referred to a separate inventive concept. In such a handlebar, the handlebar tubes (fork arms) and the steering handles (handles) are connected to each other and therefore form a continuous inner channel. In this way, for example, electric conductors of controller and the light system and also the Bowden cables of the front and/or rear braking system may be, for the most part, be provided inside the handlebar, thereby being more protected against vandalism. In an embodiment of an inventive handlebar, this is substantially comprised of two structures, which are integrated in one tube, which are formed by bending and hydraulic round pressing. 
         [0032]    A handlebar according to the invention may comprise a first and second fork tube, structurally separated from the same, and a first and second steering handle, wherein the first fork tube is structurally connected to the first steering handle and the second fork tube is structurally connected to the second steering handle. Preferably, inside the two fork tubes, a respective continuous opening extends into the steering handles, in which electric cables or braking cables (Bowden cables for example) may be arranged. On the fork tube electric contact poles may also be arranged, which may be used for example for charging batteries. A fork tube preferably includes a respective contact pole. The fork tubes may also be used as a mechanical docking means to a docking station. 
         [0033]    In a further aspect of the invention a connection to a docking station is provided on the handlebar of a bicycle, by integrating a corresponding connection point in the same. To this end, for example, two electric contacts for charging the batteries (contact poles) may be separately provided in either one of handlebar tubes. In this way, for connecting to a docking station, two clamps arranged on the handlebar tubes may be used, for example, which ensure a mechanical connection and at the same time an electric connection with the contact poles. 
         [0034]    In a variant of the invention, means for connection to a docking station are provided in the area of the bicycle&#39;s suspension. To this end, on one side or on both sides of the wheel axle contact elements may be arranged, which allow a mechanical and/or electric connection between the bicycle and a docking station. The contact elements may be provided by substantially cylindrical pins. The contact elements may be provided in such a way that they allow a mechanical and/or electric connection between the docking station and the bicycle. The electric connection may be provide by physical contact and/or by induction. A particularly fast recharging of energy accumulators (batteries) provided on the bicycle as well as a robust data exchange between docking station and bicycle may be obtained, if the charging current flows through electric contacts (sliding contacts, for example) and the data transmission is essentially contactless by induction. A bicycle provided with such contact elements allows a particularly vandal-proof coupling of bicycle with the docking station. This is particularly true when they are used in conjunction with a handlebar of above said type, since in this case the electric connections of contact elements are guided through the fork tubes, allowing a better protection against vandalism. As an alternative or addition, connection points for a docking station may also be arranged on the handlebar or on the frame structure. 
         [0035]    A further aspect of the invention refers to a bicycle stand (stand) and may also be considered as a separate inventive concept. By using a frame structure which is essentially encapsulated with respect to the outside, such a bicycle stand may also easily incorporate the function of a theft protection. It is foreseen that such a bicycle stand comprises one or preferably two supports, which are automatically locked in the unfolded state. A bicycle which is positioned on the bicycle stand cannot move. According to the invention, the (mechanical) components, which inhibit the folding of the stand, are essentially arranged within the frame structure of the bicycle, and are protected against unwanted access. A possible mechanism may comprise a closure bolt, which prevents the folding of the bicycle stand through positive locking after the unfolding. To this end, the closure bolt prevents rotations of the stand around its bearing, by being locked by a holding element. Such a holding element may be part, for example, of an electric automatic door opener. This is known, for example, in home doors of multiparty housings. The unlocking of such door openers is generally obtained by applying an electric voltage. This can be activated, for example, by an electronic control unit, after identification of an authorized user of the bicycle. According to the invention it is in particular possible that such an identification/authorization is performed by use of an RFID system. Similarly it is possible to use purely mechanical systems for the unlocking, such as a conventional key-lock system. It is advantageous if the unlocking is acoustically and/or optically signaled to the user. The unfolding and/or folding of a stand may also be automatic, for example by means of an electric assistance drive. 
         [0036]    According to the invention it is also envisaged that when the bicycle stand is unfolded, the electronics of the bicycle interrupt the energy supply to the drive motor, for example. 
         [0037]    Such a stand for a bicycle is provided for example with a folded and an unfolded position. It also comprises a locking mechanism, which prevents a folding of the stand in at least one unfolded position and allows the unlocking. In order to protect such a mechanism from unauthorized access, it is arranged within the frame structure. The locking mechanism is preferably provided with means for the electromechanical unlocking. It may also be coupled to a drive control of the bicycle. The unlocking of the stand may be performed by means of RFID and/or a mechanical key and/or by inputting a numerical code and/or by biometric identification of a user. 
         [0038]    A further aspect of the invention refers to a device for attaching a saddle to a bicycle (saddle attachment) and may also be considered as a separate concept of the invention. For a simple adjustment of saddle height it is envisaged to use a gas spring which is partially arranged within the saddle stay (saddle tube). Corresponding gas springs are known, for example, for height adjustment of office chairs. According to the invention it is advantageous, although not necessary, if the saddle stay is provided with a non-round cross-section. In particular saddle stays with an elliptical or polygonal cross-section are advantageous. On the saddle stay a sleeve corresponding with the cross-section of the saddle stay is provided. In this way, relative undesired rotations according to the invention between the saddle and the bicycle are prevented. 
         [0039]    The characteristics of the various embodiments or variants described may be combined, if they are not mutually exclusive. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0040]    The invention is explained in the following by means of examples, in connection with the drawing. In particular: 
           [0041]      FIG. 1  shows a bicycle with a drive unit; 
           [0042]      FIG. 2  shows a drive unit with a frame structure, viewed from rear upper-right; 
           [0043]      FIG. 3  shows detail A of  FIG. 2 , 
           [0044]      FIG. 4  shows a drive unit with a frame structure viewed from rear upper-left; 
           [0045]      FIG. 5  shows detail B of  FIG. 4 , 
           [0046]      FIG. 6  shows a frame structure and a wheel hub in a first view, 
           [0047]      FIG. 7  shows an exploded view of a frame structure; 
           [0048]      FIG. 8  shows a bicycle stand in a first view; 
           [0049]      FIG. 9  shows a bicycle stand in a further view; 
           [0050]      FIG. 10  shows section C-C of  FIG. 9 ; 
           [0051]      FIG. 11  shows a bicycle stand in a further view; 
           [0052]      FIG. 12  shows detail D of  FIG. 11 ; 
           [0053]      FIG. 13  shows a bicycle stand in a further view; 
           [0054]      FIG. 14  shows an exploded view of a bicycle stand; 
           [0055]      FIG. 15  shows a handlebar of a bicycle in a first view; 
           [0056]      FIG. 16  shows detail E of  FIG. 15 ; 
           [0057]      FIG. 17  shows a handlebar of a bicycle in a second view; 
           [0058]      FIG. 18  shows a saddle in a first view; 
           [0059]      FIG. 19  shows a saddle in a second view; 
           [0060]      FIG. 20  shows section F-F of  FIG. 19 ; 
           [0061]      FIG. 21  shows detail G of  FIG. 20 ; 
           [0062]      FIG. 22  shows a frame structure; 
           [0063]      FIG. 23 a    shows detail H of  FIG. 22 , wherein the mounting elements are in a first position; 
           [0064]      FIG. 23 b    shows detail H of  FIG. 22 , wherein the mounting elements are in a second position; 
           [0065]      FIG. 24  shows contact elements in the area of the front wheel of a bicycle; 
           [0066]      FIG. 25  shows detail I of  FIG. 24 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0067]      FIG. 1  shows a bicycle  100  with a possible frame structure  200  according to the invention. The bicycle  100  shown is provided with a front wheel  102  and a rear wheel  103 . The rear wheel  103  is connected to the frame structure  200 , which in turn is connected, through a connection support formed by a lower tube  126  and a steering tube  407 , to a handlebar  112 . The handlebar  112  is connected, through a fork  408 , comprising a first fork leg  409  and a second fork leg  410  with the hub  105  of the front wheel  102 . The bicycle  100  may be provided with a bicycle stand  500 . The bicycle  100  is provided with a pedal crank drive with a first ( 115 —not shown) and second pedal crank  116  and a first ( 117 —not shown) and second pedal  118 . The drive torque provided by the driver is transmitted through a drive unit to the rear wheel  103 . In the bicycle shown the mechanism is encapsulated in the frame structure  200  and is covered on the sides by two front covers  217  and two rear covers  215 . The covers may be provided with means for deflecting the air during driving, such as shown, through air guide elements  218 , which guide the air flowing around the frame structure during driving, for example, to a braking system. A bicycle  100  with a frame structure  200  according to the invention may also be provided with a saddle  312 , or multiple saddles. According to the invention, such covers may not necessary, or may also be provided in one or more pieces. The bicycle  100  shown may also be provided with further components known to the skilled in the art, such as protective metal sheets  104  or a luggage support, which may be provided on a corresponding fixing element  111 . 
         [0068]    As shown in  FIG. 2 , the transmission of a drive torque applied by the driver through the pedals  117 ,  118  and pedal cranks  115  (not shown),  116  to the pedal bearing shaft  114  may be transmitted according to the invention for example through a first belt pulley  120  and a toothed belt  119  to a second pulley  121  and from there to a wheel hub  105 . For guiding and preloading the toothed belt  119 , one or more belt tensioning devices  125  or guiding pulleys (not shown) may be used. The toothed belt  119 , as shown in  FIG. 2 , may be arranged at least partially in the second rocker  204 . Alternatively, it also may be partially arranged in the first rocker  201 . The second rocker  204  may have a second (inner) compartment  205 , in which, apart from the toothed belt  119 , further elements may be provided. It is conceivable, that the wheel hub  105  has a hub gear, through which the torque applied by second belt pulley  121  is converted and transmitted to the rear wheel  103 . The rear wheel  103 , or the rear wheel hub  105  may be mounted on the frame structure  200  by means of fixing screws  109  and a fixing nut  110 . To this end, it may be provided on the first rocker  201  with a first bracket  203  and on the second rocker  204  with a second bracket  206 , which may house the fixing screws  109 . A frame structure  200  according to the invention, as shown in  FIG. 2 , may also be provided with one or more openings  221 , for example, for fixing a saddle tube (not shown). 
         [0069]    As shown in  FIG. 3 , in a frame structure  200  according to the invention, the axle of a rear wheel may be supported in that fixing screws  109  disposed on hub  105  of rear wheel are inserted into a drop-out end  209  on second bracket  206  and are fixed by a fixing nut  110 . The wheel axle may additionally be held by an axle sleeve  127 , which is supported in drop-out end  209 . 
         [0070]    As shown in  FIG. 4 , a bicycle  100  according to the invention may also be provided with at least one electric auxiliary drive or motor  113 , which is preferably arranged in a drive box  213  on the pedal bearing shaft  114 . The energy storage for motor  113  may be provided by one or more battery packs  122 , preferably inside the frame structure  200 . A battery pack  122  may be solidly mounted inside the rocker  201 , and may be connected to same, as shown, for example, by means of attachment means formed by a mounting bracket  123 , or alternatively may be simply removed from the frame structure  200  for example by means of a folding mechanism. In the embodiment of  FIG. 4 , the battery packets  122  are provided in a first compartment  202  inside the first rocker  201 . The frame structure  200  is also provided, in the area of the drive box  213  with enough space for further components, such as the electronics of the drive control  124 . 
         [0071]    As shown in  FIG. 5 , in a preferred embodiment of the invention, the first  203  and second bracket  206  are sized in a way that both a belt pulley  121 , a wheel hub  105  with hub gears and a disk brake, o the roller brake type, for example, with a brake disk  107  and brake caliper  108 , may be positioned between both the drop-out ends  209 . Due to both brackets  203  and  206 , such an arrangement is possible also with a relatively narrow frame structure  200 , or wheel box  212 . Brackets  203  and  206  may also be provided with additional elements, such as holes for fixing a brake caliper  108 . 
         [0072]    As shown in  FIGS. 6 and 7 , a frame structure  200  according to the invention may be comprised of relatively few metal sheet parts. The frame structure  200  shown in  FIG. 6  is essentially comprised of five metal sheet parts, which are connected by means of welded connections, glued connections or other joining techniques, suitable for metal sheet connections. In the embodiment shown, a swingarm structure  225  is connected with a first  203  and second bracket  206  mechanically to a frame bridge  219 . For a better connection, the single components may be provided with corresponding slots  210  and springs  211 , which are used as positioning means as well as for increasing the connection resistance. The metal sheet parts may be relatively inexpensive to produce by punching, laser cutting and bending. The swingarm structure  225  is made of a first metal sheet part and has, in the view from above (Z direction) essentially a U-shape. This first metal sheet part is essentially bent (curved) in a first bending plane P to form a first U-shape. As shown, in a swingarm structure, its rigidity may be enhanced by an upper and lower seam or folds  226 . At the same time, such a folding of edges may be used for creating compartments  202  or  205  in both swingarms  201  and  204 . The frame bridge  219  shown is comprised of a second metal sheet part and has an essentially U-shaped construction, in the side view (Y direction), and radially delimits, with shoulder of swingarm structure  225  a drive box  213 . This second metal sheet part is essentially bent (curved) in a first bending plane Q to form a second U-shape. As schematically shown in  FIG. 7 , the frame bridge  219  and the swingarm structure  225  in the frame structure  200  shown are mutually arranged in such a way that the first bending plane P is essentially perpendicular to the second bending plane Q. As shown, a frame bridge  219  according to the invention may be provided with different openings, such as an opening  220  for connecting a lower tube (lower tube not shown), an opening  221  for connecting a saddle stay (saddle stay not shown) or an opening  222  for partial housing of a bicycle stand (bicycle stand not shown). At the same time, a frame bridge  219  according to the invention may have different attachment surfaces  223 , which in the embodiment shown are planar, but may also be curved. For increasing the structural integrity of the frame bridge  219 , this may have, as shown, preferably tabs or folded edges  224 , which increase the bending and deforming resistance. In addition, in the drive box  213 , as shown, a partition plate or slide plate  207  as a support structure may be arranged, which has different functions. It increases the structural stability of a frame structure  200  on one side, and it may be used as a spatial separation of the drive box  213  on the other side, and may for example separate a partial volume protected from humidity of a frame structure  200 , in which for example electronic/electric components of drive are arranged, from a partial volume, which is only conditionally protected, in which the belt drive is positioned, for example. A supporting structure  207  may however be used also as a mounting means for a motor or other components, for example. To this end, it may be provided with corresponding cavities  208 , if necessary. 
         [0073]    In an encapsulated frame structure  200  according to the invention, an advantageous embodiment of a protected bicycle stand  500  may be used, as shown in  FIGS. 8 to 14 . A bicycle stand  500  according to the invention is also characterized by at least one unfolded and folded position. Such a bicycle stand  500  comprises a support part, which is formed by a first  501  and second support  502 , and a mechanism which is provided inside a frame structure, for unfolding and fixing supports  501 ,  502 . In the embodiment shown, the supports have at their lower ends support feet  514 , which are made of an elastic material, such as rubber, for example. The supports are attached, at their other ends, to a support plate  506 , by welding points, for example. The support plate  506  is connected, on both sides, by two bolts  507 , in a rotatable articulated way to two stand supports  513 . For a better support, sleeves  510  are also used. The stand supports  513  have holes  515 , which are used for attaching to the frame structure  200 , for example by means of screws or rivets. For improving such a connection, a kind of frame plate  511  may be used, which is also provided with holes  515 . As shown in  FIGS. 8 to 14 , a bicycle stand according to the invention may have, in some embodiments, also a locking mechanism, which comprises an automatic door opener, which is solidly connected to both stand supports  513  on both sides. A cross bar  512  is also supported, like the stand support  513 , in a rotatable articulated way on bolt  507  and is also connected with a connecting pin  518  to the stand support  513 , so that between these bodies no relative rotations may take place. A locking bolt  503  is rotatably connected through an axle pin  519  with the cross bar  512  and, as shown in  FIG. 10 , in the unfolded position of bicycle stand  500 , is pressed by a torsion spring  504  against the door opener  505 . In this way, a folding of the stand is prevented by a locking element  517  which is positioned on the door opener latch  516  (see  FIG. 12 ). 
         [0074]    In order to fold the bicycle stand  500  in a closed position, a tension may be applied on the door opener  505 , whereby a rotation of door opener latch  516  is allowed (see  FIG. 12 ). In this way, the closure bolt  503  is no more blocked by the locking element  517  of the door opener latch  516  and a rotation r of supports  501 ,  502  around axis of bolts  507  is allowed, whereby the bicycle stand  500  may be moved into a folded position (see  FIG. 13 ). Such a mechanism is allowed since the relatively simple locking mechanism is arranged inside the frame structure  200  and is therefore protected from direct access or manipulation. Due to the use of a conventional automatic door opener  505 , it is also possible to use a reliable and relatively cost effective electromechanical locking system, which also provides the user in general with a notification of unlocking by emitting a buzzing sound. The axle pins  519  and bolts  507  of a bicycle stand according to the invention may be fixed by fixing rings  509 , whereby in case of failure of mechanism, relatively simple parts of the same may be replaced. In order to detect the correct closure of stand, it may be provided with an end switch, which detects the contact between the closure bolt  503  and the door opener  505 , or the door opener latch  516  or the locking element  517 . 
         [0075]    As shown in  FIG. 15 , a bicycle  100  according to the invention may be provided with a docking means  400  for connecting the bicycle  100  to a renting station, for example. To this end, the embodiment of  FIGS. 15 to 17  of a bicycle  100  according to the invention is provide with a two-part bicycle fork  408 . It comprises, in the embodiment of the invention, a first fork leg  409  as well as a second fork leg  410 . Both fork legs  409 ,  410  are provided by round tubes, and extend from hub  105  of front wheel  102  through the area of the steering tube  407  into the first  414  and second steering bar  415 . Both round tubes are provided, in the area of steering tubes  414 ,  415 , with a smaller (tapered) diameter with respect to the area of the hub  105 . Such a tapering may be preferably provided by round pressing. The use of such continuous tubular fork legs allows, among other things, a protected arrangement of brake cables  402 ,  404  inside the fork legs  408 ,  409 , whereby vandalism may be relatively prevented. Brake cables  402 ,  404  may be introduced, relatively directly, at first  401  and second brake grip  403  into fork legs  409  or  410 . The same holds for connections to gear grip  406  and a console  405  being part of the gear shift or electronic control of bicycle  100 . In the area of steering tube  407 , both fork legs  409 ,  410  are held by an upper and lower fork bridge  416 , as shown, among other things, in  FIG. 16 . Fork legs  409  and  410  may be preferably provided, in the area of docking means  400  with a first  411  and second contact pole  412 , through which the batteries  122  may be charged, for example. 
         [0076]      FIG. 18  shows a possible embodiment of a saddle attachment  300  according to the invention. Such an embodiment comprises, on one hand, the saddle proper  312 , a saddle stay  301 , as well as an adjustment mechanism, which is essentially positioned in the saddle stay  301  and in the saddle tube  303 , for adjusting the desired saddle height. This may be actuated by means of an adjustment lever  302  underneath the saddle. As shown in  FIG. 20 , such an adjustment mechanism may comprise a gas spring  304 , which is provided, at its lower end with an anchor  311  in the frame structure  200 , for example, on support structure  207  and is connected, at the other end, with the saddle stay  301  or directly to the saddle  312 . In the embodiment of  FIG. 20 , the piston rod  306  of the gas spring  304  is connected to a support of saddle  312 . In order to prevent a relative rotation between the saddle  312  and the rest of the bicycle  100 , according to the invention it is envisaged that the saddle stay  301  does not have a circular cross-section. In the embodiments of  FIGS. 18 to 21 , the saddle stay  301  has a rectangular cross-section. In the area of the upper end of saddle tube  303 , according to the invention, a sleeve  308  is provided as a guide for the saddle stay  301 , which is provided with an inner cross-section corresponding to the outer cross-section of the saddle stay  301 —therefore an essentially rectangular inner opening. Sleeve  308  is solidly connected to the saddle tube  303 , for example by screwing  309 . In addition, the saddle stay  301  may also be provided, in the area of its lower end, with its own outer guide sleeve  310 , which guides the saddle stay  301  in the saddle tube  303  and also limits the maximum saddle height, for example. 
         [0077]      FIG. 22  shows a further frame structure  200  according to the invention, wherein the housing means for the rear wheel are provided by first and second brackets  203 ,  206  and first and second mounting elements  230 ,  231  arranged on the same. These are adjustable with respect to rockers  201 ,  204 , as shown in the following  FIGS. 23 a  and 23 b   . The support structure  207  of frame structure  200  shown comprises a plate, which is mechanically partially reinforced by a second plate overlaying the same. As schematically shown in  FIG. 23 a   , by means of dotted arrows, the position of mounting elements  230 ,  231  with respect to brackets  203 ,  206  and also to rockers  201 ,  204  may be adjusted. To this end, the mounting elements  230 ,  231  are connected, by means of adjustment screws  233  which are supported inside oblong openings  232 , to brackets  203 ,  206 . On the adjustment screws  233  nuts are positioned, so that the mounting elements  230 ,  231  may be fixed in different positions with respect to brackets  203 ,  206  (or rockers  201 ,  204 ). An axle of a rear wheel (not shown), positioned in the drop-outs  209  may be positioned at different distances from the pedal bearing shaft (not shown) and therefore a drive chain or drive belt may be tensioned or loosened between the pedal bearing shaft and the rear wheel. In this way, a rear wheel may be easily mounted or replaced without the need for a chain or belt tensioning device.  FIG. 23 a    shows frame structure, in which the mounting elements  230 ,  231  are in a first position, in which a drive belt would be loosened.  FIG. 23 b    shows mounting elements  230 ,  231  in a second position, in which a drive belt would be in a tensioned position. 
         [0078]      FIGS. 24 and 25  show a detail of an embodiment of a bicycle, in which a docking element  413  composed of two parts is positioned in the area of the suspension of the front wheel  102  Both parts are positioned on both sides in the axial direction, with respect to wheel  102 . The docking element  413  shown has a cylindrical, or pin-like, shape, whereby a particularly simple connection to a docking station (not shown) may be achieved. As shown in  FIG. 25 , such a docking element  413  may be provided with several axially separated areas, such as a contact pole  412  for electric contacting. Such an electric contact is obtained in the embodiment shown through sliding contacts. A second contact pole (not shown) is positioned on the other part of docking elements  413 . According to the invention, though, two contact poles may be provided on the same part. The areas axially adjacent to the contact pole  412  are used, among other things, to perform a secure mechanical connection between the bicycle and a docking station.