Description of the Prior Art In general, bicycles include front and rear wheels, pedals to generate power by being stepped by a user, and a power transmission means to transfer the power generated by rotation of the pedals to the rear wheel.

The power transmission means includes a driving sprocket mounted at the pedals, a driven sprocket having a latch for transmit power toward the rear wheel in one direction, and a chain to connect the driving sprocket to the driven sprocket.

The driven sprocket is provided with a latch member to be engaged with the rear wheel only in one direction.

As described above, the conventional bicycle travels only in one direction, that is, forwardly by rotation power which is generated by rotating the pedals forward and transmitted through the chain connecting the driving sprocket to the driven sprocket.

Therefore, the user has to rotate the pedals only in the forward direction, and such a same movement makes the user's

leg-muscles unbalanced and makes the user feel bored and tired easily, while it is impossible to relieve his fatigue while riding the bicycle.

In the conventional travelling device, even though it is possible to stop rotation of the pedals or rotate the driving sprocket and the chain reversely in response to reverse rotation of the pedals, the power is cut off and not transmitted by a forward latch means provided inside the driven sprocket so that the driven sprocket races.

In order to resolve the above disadvantages, Korean Patent Publication No. 95-13589 has suggested a reverse travelling device which includes a forward clutch to alternatively transmit driving power to a driving sprocket, a feed shaft of which engagement state is changable by means of an operation lever, an idle gear and a reversing gear wheel, so that the bicycle may travel forward even in case of backward rotation of the pedals, developing the user's feet and lets in balance.

The reverse travelling device has, however, still problems that the structure thereof is too complicated and this reverse travelling device cannot be adapted to the driving wheel at the driven sprocket side of the currently widespread bicycles, so that a new bicycle should be purchased.

Furthermore, such a proposed reverse travelling device has no change gear, so that there is a tendency to avoid use of it.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a travelling and accelerating system for bicycles which may transmit power in case of not only forward rotation but also

backward rotation of pedals.

It is another object of the present invention to provide a travelling and accelerating system for bicycles which may operate in both forward and backward directions of pedal rotation so that users may develop their leg-muscles in balance and feel little bored and tired while riding the bicycle.

It is a further object of the present invention to provide a travelling and accelerating system for bicycles which is provided with a change gear integrally for accelerated travelling so that an additional change gear is not necessary any more and users may purchase a bicycle at a relatively low cost.

To achieve the above objects, the present invention is directed to a travelling and accelerating system for bicycles which includes a frame having a front wheel at a front part and a rear wheel at a rear part thereof; a pair of pedals fixed at both sides of a shaft which is rotatably supported at a boss being fixed under a center of the frame, to be driven by a user's fret. a driving sprocket axially fixed on the shaft for transmitting rotation power via a chain to the rear wheel; a housing attached at one side of the boss to be closed with a cap and having a hollow cross-sectional shape to accomodate accessories; a pinion axially fixed on the shaft beside the driving sprocket in the housing; a first gear member accommodated in the housing and having an inner gear part and an outer gear part; a second gear member movably contacted the first gear member and provided with planetary gears to be engaged with the inner gear part of the first gear, the planetary gears being fixed by pins and rotatable with relation to the pins; latch means respectively inserted in the first gear member and the second gear member

for rotate them respectively in one direction; and a conversion control part connected to a release cable outside the housing for setting a travel mode or an acceleration mode corresponding to rotation directions of pedals by controlling engagement of the first gear member and the second gear member according to the user's selection.

According to the travelling and accelerating system for bicycles of the present invention, the user may simply change the pedals'rotation direction forward and backward by operating the conversion lever while keeping forward travelling of the bicycle, thereby promoting balanced development of leg-muscles.

Also, it becomes possible to selectively accelerate travelling speed by increasing rotation number with relation to a certain rotation.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will become more fully understood frorn the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: Fig. 1 is a disassembled perspective view showing the construction of a first embodiment of the present invention; Fig. 2 is a schematic view of a principal part of the first embodiment which is in operation of forward travelling ; Fig. 3 is a schematic view of a principal part of the first embodiment which is in operation of accelerated forward travelling; Fig. 4 is a schematic view of a principal part of the first embodiment which is in operation of backward travelling ;

Fig 5 is an enlarged cross-sectional view showing principal parts which are assembled ;<BR> Fig. 6 is a front view showing the principal parts of Fig. 5 ; Fig. 7 is a disassembled perspective view showing the construction of a second embodiment of the present invention ; Fig. 8 is a schematic view of a principal part of the second embodiment which is in operation of forward travelling; Fig. 9 is a schematic view of a principal part of the second embodiment which is in operation of accelerated forward travelling; Fig. 10 is a schematic view of a principal part of the second embodiment which is in operation of backward travelling ; and Fig. 11 is a partially taken cross-sectional view showing principal parts which are assembled.

DETAILED DESCRIPTION OF THE INVENTION Fig. 1 to Fig. 6 shows a construction of a travelling and accelerating system for bicycles according to a first embodiment of the present invention, in which a bicycle may travel forward by means of forward and backward latch means 80 and 90 with engagement with latches 81 and 82 of a latch protrusion 72 and a latch gear 73.

On the other hand, Fig. 7 to Fig. 11 shows a construction of a travelling and accelerating system for bicycles according to a second embodiment of the present invention, in which a bicycle may travel forward by the forward and backward latch means 80 and 90 formed in a clutch bearing structure.

Fig. 1 and Fig. 7 are perspective views respectively

showing disassembled principal parts of the present invention, and Fig. 2 and Fig. 8 are operational views respectively showing forward travelling states wherein rotation control latches 110 and 120 rise up and a first gear member 60 and a second gear member 70 do not engage with each other so that pedals 20 rotate in a same direction with a travelling direction of a bicycle.

Fig. 3 and Fig. 9 are operational views respectively showing that a driving sprocket 30 is driven by the rotation control latch 10 which controls rotation of the first gear member 60 and sped up by a planetary gear 74 in a predetermined ratio.

Fig. 4 and Fig. 10 are operational views respectively showing forward travelling in case of backward rotation of the. pedals 20, since the rotation control latch 120 controlling the rotation of the second gear member 70 operates in an advanced position to prevent the second gear member 70 from rotating.

The bicycle includes a frame 10 forming a frame body of the bicycle, front and rear wheels, which are not shown, provided rotatably to the frame 10, and a boss 21 fixed to mount the pedals 20 under a center of the frame 10 to support rotation of the pedals 20.

The pedals 20 are fixed inside the boss 21 and a shaft 22 is rotatably inserted through the inside of the boss 21 by means of bearings (is not shown). Therefore, when a user steps the pedals 20 at both sides of the boss 21, rotational power is transmitted to the shaft 22 so that the rotational power drives a driven sprocket (is not shown) at the rear wheel via a chain 31 by means of the driving sprocket 30 which is axially mounted on the shaft 22, thereby the bicycle travelling forward.

The driving sprocket 30 which is axially mounted on the

shaft 22 is positioned in a housing 40 to transmit the rotational power via the chain 31.

The housing 40 is fixed on the frame 10 at one side of the boss 21 and closed with a cap 41 at its opening, accommodating various accessaries therein, so that external impurities may be prevented from being introduced therein and viscosity of oil which is necessary for operating the accessaries may be protected.

The housing 40 accommodates the driving sprocket 30, a pinion 50, the first gear member 60, and the second gear member 70 therein. That is, in the housing 40, the pinion 50 is axially fixed on the shaft 22 at one side of the driving sprocket 30 to rotate together with the driving sprocket 30.

Also, the housing 40 has an outer gear 61 at its outer peripheral and an inner gear 62 formed at its inner peripheral, and the first gear member 60 is positioned in the hollow inside of the housing 40, wherein the first gear member 60 has a plurality of latch protrusions 63 which are formed in one direction, as shown in Fig. 1 to Fig. 6.

The first gear member 60 is coupled with the second gear member 70, both first gear member 60 and the second gear member 70 being movable each other but unable to be separated from each other. The second gear member 70 is formed with a plurality of outer gears 71 and fixed with a plurality of the planetary gears 74 by means of pins 75. The planetary gears 74 are fixed to the center of the second gear member 70 and engaged with the inner gear 62 of the first gear member 60, being rotatably with relation to the pins 75 in the housing 40.

The second gear member 70 has a plurality of latch gears

73 in a predetermined interval along an inner peripheral of a center opening of the second gear member 70.

In the first embodiment of the present invention, the inner diameter of the first gear member 60 is the same with the inner diameter of the second gear member 70 and the latch protrusions 63 of the first gear member 60 and the latch gears 73 of the second gear member 70 are oppositely formed each other.

The first and second gear members 60 and 70 are provided with a latch member 85 which has latches 81 and 82 facing each other at different positions in a predetermined interval on the latch means 80, so that the latches 81 and 82 are respectively engaged with the latch protrusions 63 and the latch gears 73.

Outside the latch member 85 is fixed pedals 20 by means of bolts 83, so that as the pedals 20 are stepped, the first gear member 60 and the second gear member 70 are selectively driven via the latch member 85. In this case, the planetary gears 74 control travelling speed of the bicycle, for example, in 1: 1 Forward Travelling mode, 1: 1 Backward Travelling mode, or Accelerated Travelling mode to a predetermined speed ratio.

A conversion control part 100 is mounted outside the housing 40 to selectively control the latch member 85 to function in the 1: 1 Forward Travelling Mode and 1: 1 Backward Travelling mode, or Accelerated Travelling mode to a predetermined speed.

The conversion control part 100 controls the travelling by fixing any one or both of the first and second gear members 60 and 70 not to rotate, or by making them rotate freely.

A case 121 is attached to the housing 40 and rotation control latches 110 and 120 are accommodated in the case 121 to be associated with the inside of the housing 40 and coupled with

a cam shaft 111 to be controlled thereby.

The cam shaft 111 is connected with a release cable 104 which is provided at a convenient position with the user, for example, a position around a handle of the bicycle, so that the user may change a position of the cam shaft 111 by means of the release cable 104 for decreasing or increasing the rotation control latches 110 and 120, thereby controlling the rotation of the first gear member 60 and the second gear member 70.

The case 121 has a hollow inside and surrounds the conversion control part 100, forming a path from outside the housing 40 to the hollow inside thereof.

Referring to Fig. 1 to Fig. 6, the cam shaft 111 passes through the case 121 and is rotatably supported at both end <BR> <BR> parts. 1 lowever, referring to Fig. 7 showing a second embodiment of the present invention, the cam shaft 111 is supported by a supporting part which is integrally formed to the housing 40 and the case 121 functions only to protect the conversion control part 100 from outside by surrounding it.

The cam shaft 111 is formed with cam protrusions 101 and 102 at different positions which control positions of a pair of the rotation control latches 110 and 120 thereon.

The cam shaft 111 is connected at its one end part to a conversion selection lever (not shown) and the release cable 104 which are positioned around the handle of the bicycle, so that rotation angle of the cam shaft 111 is converted by a wire which is pulled in response to manipulation of the conversion selection lever.

Therefore, if any one of the pair of rotation control latches 110 and 120 operates to be engaged with the first and second

gear members 60 and 70, thereby restricting the rotation of the first and second gear members 60 and 70, or if the latches 110 and 120 do not operate and the latches 110 and 120 are not engaged with the first and second gear members 60 and 70, then the first and second gear members 60 and 70 may rotate simultaneously.

The rotation control latches 110 and 120 have a sharp end part like a knife and are interposed between teeth of the first and the second gear members 60 and 70. The first and second gear members 60 and 70 may be engaged with each other, of which center portions are rotatably mounted on the axis 30.

The rotation control latches 110 and 120 further have an upper part, which is elastically supported by a spring 131 to rotate with relation to an axial pin 130 according to positions of the cam protrusions 101 and 102 in response to the position conversion of the cam shaft 111, thereby controlling the rotation of the first and second gear members 60 and 70.

The latches 110 and 120 are mounted at a symmetrical position in a pair in the case 121, wherein the latch 110 being able to be engaged with the first gear member 60 and the latch 120 being able to be engaged with the second gear member 70.

In the first embodiment as shown in Fig. 2 to Fig. 4, a pressure coil spring is elastically mounted in the inner walls of the case 121 and functions as the spring 131 to elastically support the cam protrusions 101 and 102. However, in the second embodiment as shown in Fig. 8 and Fig. 11, a torsion spring like a wire is adapted as the spring 131 and effects the same function.

Referring to the second embodiment of the present invention

as shown in Fig. 7 and Fig. 11, clutch bearings 91 and 92 instead the forward and backward latch means 80 and 90.

A first gear member 60 has a sleek inner peripheral 62 without teeth, so that a clutch bearing 91 is inserted in the inner peripheral 62, the clutch bearing 91 being provided with a plurality of balls 91c and springs 91d in a predetermined interval.

A second gear member 70 is also inserted with a clutch bearing 92 in the same manner with the first gear member 60.

The clutch bearings 91 and 92 are respectively formed with a plurality of grooves 91a and 92a in a predetermined interval and have slanted surfaces 91b and 92b respectively, so that the balls 91c and 92c and the springs 91d and 92d are respectively fitted into the grooves 91a and 92a.

Therefore, when rotation direction of the clutch bearings 91 and 92 is different from that of the first and second gear members 60 and 70, that is, different from that of the slanted surfaces 91b and 92b, the balls 91c and 92c slide along the slated surfaces 91b and 92b into positions where a distance from the first and second gear members 60 and 70 to the slated surfaces 91b and 92b becomes narrow.

Then, the balls 91c and 92c are closed in the narrow space between the clutch bearings 91,92 and the first and second gear members 60,70, so that the clutch bearings 91,92 and the first and second gear members 60,70 become coupled integrally, thereby being controlled to rotate respectively in one direction.

Detailed description with regard to the operation of the clutch bearings 91,92 is omitted since it has already been widely known in the routine mechanical fields.

In the meantime, the slanted surface 91b of the clutch

bearing 91 is formed in an opposite direction to the slanted surface 92b of the clutch bearing 92. Therefore, the first gear member 60 and the second gear member 70 are controlled in different directions from each other.

As described hereinabove, even though the construction of the forward and backward latch means 80 and 90 is different between the first embodiment and the second embodiment, the same function and effect may be achieved.

Now, operation by steps will be described in more detail.

(Forward Normal Travel) Referring to Fig. 2 to Fig. 8, according to manipulation of the lever positioned around the handle, the cam shaft 111 connected to the release cable 104 is in a neutral position and the first and second gear members 60 and 70 are not engaged with the pair of rotation control latches 110 and 120 since the rotation control latches 110 and 120 are in contact with the cam protrusions 101 and 102.

Therefore, if the user steps the pedals 20 in the clockwise direction as shown by an arrow in Fig. 2, the latch member 85 connected to the pedals 20 by means of the bolts 83 and the clutch bearings 91 and 92 coupled with the shaft 22 rotate in a same direction.

Referring to the first embodiment of the present invention, the latch member 85 is elastically provided with latches 81 and 82 of which opening directions are opposite. Therefore, the latches 82 are engaged with the latch gears 73 of the second gear member 70, so that the latch member 85 is coupled with the second gear member 70 integrally. Simultaneously the other latches 81 are engaged with the latch protrusions 63 of the first

gear member 60, so that the first gear member 60 is prevented from rotating backward.

Referring to the second embodiment of the present invention, since the balls 92c are closed between the slanted surfaces 92b of the clutch bearing 92 and the second gear member 70 and the balls 91c are closed between the opposite slated surfaces 91b of the clutch bearing 91 and the first gear member 60, the clutch bearings 91 and 92 become coupled with the first and the second gear members 60 and 70 integrally, preventing backward rotation of the first gear member 60.

The planetary gears 74 movably mounted to the second gear member 70 are engaged with the inner gear 62 of the first gear member 60, so that it becomes impossible for the planetary gears 74 to rotate.

Therefore, when the pedals 20 are stepped by the user for forward travelling, the latch member 85 which is coupled with the first gear member 60 and the second gear member 70 rotates, so that the planetary gears 74 supported by the pins 75 race and the pinion 50 which is fixed by the driving sprocket 30 rotates in the clockwise direction, being engaged among the planetary gears 74, thereby the driving power being transmitted to the rear wheels via the chain 31.

In this case, if the user stops stepping the pedals 20 or steps the pedals 20 backwardly, the latch 82 of the latch member 85 rotates in a direction to be released from the latch gear 73 of the second gear member 70, so that the stopping of the rotation of the pedals 20 while travelling the bicycle or backward stepping of the pedals 20 become possible without transmitting the power.

(Accelerated Forward Travelling) As shown in Fig. 3 and Fig. 9, according to manipulation of the lever positioned around the handle, the cam shaft 111 connected to the release cable 104 rotates in a direction, so that the first gear member 60 is not engaged with the pair of rotation control latches 110 and 120 since the rotation control fatches 110 and 120 are in contact with the cam protrusions 101 and 102, and the second gear member 70 is rotatable.

Therefore, if the user steps the pedals 20 in the clockwise direction, the latch member 85 and the clutch bearings 91 and 92 rotate in a same direction.

Referring to Fig. 1 showing the first embodiment of the present invention, the latch member 85 is fixed to the pedals 20 by means of the bolts 83. On the other hand, referring to Fig. 7 showing the second embodiment of the present invention, the clutch bearing 92 is coupled with the shaft 22 having a tetragonal end part, wherein the clutch bearing 91 is coupled with the clutch bearing 92 by a shaft part 92s and a boss 91s respectively formed in the shape of tetragonal, and the clutch bearings 91 and 92 rotate together.

The latch member 85 has the opposite latches 81 and 82 at different positions in a predetermined interval on the latch means 80, so that the latches 81 and 82 are respectively engaged with the latch protrusions 63 of the first gear member 60 and the latch gears 73 the second gear member 70.

However, the rotation control latch 110 is in an advanced position and engaged with the teeth of the first gear member 60, so that the first gear member 60 is impossible to rotate.

In the meantime, referring to the second embodiment of the

present invention, the slanted surface 91b of the clutch bearing 91 is formed in an opposite direction to the slanted surface 92b of the clutch bearing 92, so that the first gear member 60 and the second gear member 70 are controlled to rotate in a different direction from each other.

The planetary gears 74 movably mounted to the second gear member 70 are engaged with the inner gear 62 of the first gear member 60. When the second gear member 70 rotates, the planetary gears 74 race in response to the rotation of the second gear member 70 since a common center of the planetary gears 74 rotates in the same direction with the second gear member 70.

Simultaneously, the planetary gears 74 rotate by the inner gear 62 of the first gear member 60, so that the pinion 50 being engaged among the planetary gears 74 obtains a rotation number which is increased by both the racing and the rotation of the planetary gears 74.

Therefore, when the pedals 20 are stepped by the user for forward travelling, the latch member 85 and the clutch bearing 92 which are coupled with the second gear member 70 rotates in the same direction with the second gear member 70, so that the pinion 50 which is coupled with the driving sprocket 30 is accelerated in its rotation by a speed ratio of the planetary gears 74 positioned between the inner gear 62 of the stopped first gear member 60 and the pinion 50, thereby the driving power being transmitted to the rear wheels via the chain 31.

(Backward Normal Travelling) As shown in Fig. 4 and Fig. 10, according to manipulation of the lever positioned around the handle, the cam shaft 111

connected to the release cable 104 is positioned aside, so that the second gear member 70 is engaged with the pair of rotation control latches 110 and 120 since the rotation control latches 110 and 120 are in contact with the cam protrusions 101 and 102.

Therefore, if the user steps the pedals 20 in the counterclockwise direction as shown by an arrow, the latch member 85 and the clutch bearings 91 and 92 rotate in a same direction, the latch member 85 being connected by the bolt 83 in Fig. 4 and by the shaft 22 in Fig. 10 to the pedals 20.

Referring to the first embodiment of the present invention, the latch member 85 is elastically provided with latches 81 and 82 of which opening directions are opposite. Therefore, the latches 82 are not engaged with the latch gears 73 of the second gear member 70, and simultaneously the other latches 81 are engaged with the latch protrusions 63 of the first gear member 60, so that only the first gear member 60 rotates backwardly.

Therefore, since the balls 91c are closed between the slanted surfaces 91b of the clutch bearing 91 and the first gear member 60 and the balls 92c are free relatively wide spaces between the opposite slated surfaces 92b of the clutch bearing 92 and the second gear member 70, only the clutch bearing 91 becomes coupled with the first gear member 60 integrally, thereby only the first gear member 60 rotating backwardly.

In the meantime, the planetary gears 74 movably mounted to the second gear member 70 are engaged with the inner gear 62 of the first gear member 60, so that the planetary gears 74 rotate but not race.

Therefore, when the pedals 20 are stepped by the user for backward travelling, the latch member 85 and the clutch bearing

91 rotates backwardly being coupled with the first gear member 60, so that the planetary gears 74 supported by the pins 75 rotate and the pinion 50 which is engaged among the planetary gears 74 rotates normally in the forward direction, thereby transmitting the driving power to the rear wheels via the chain 31 in the opposite direction to the rotation of the pedals 20. At this time, the rotation ratio is 1: 1.

According to the present invention as described hereinabove, if the user simply manipulates the operation lever, the bicycle may run forward regardless of the forward rotation and the backward rotation of the pedals, so that the user may develop their leg-muscles in balance and feel little bored and tired while riding the bicycle as well as accelerating the running speed selectively.

Furthermore, according to the present invention, any additional change gear is not necessary any more and the users may obtain a bicycle at a relatively low cost.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as described in the accompanying claims.