Background Art Generally, bicycles have a configuration including a drive sprocket driven by a pedaling operation of the user, and a free wheel connected to the drive sprocket by means of a chain and adapted to transmit a rotating force of the drive sprocket to the drive wheel of the bicycle. Braking devices for such bicycles are well known which include a lining adapted to come into contact with the rim of a bicycle wheel, thereby braking the wheel by a frictional force generated between the rim and lining.

In order to run such a bicycle from its stopped or braked state, it is necessary to pedal with a strong force. As the pedal operation is continued, the bicycle is gradually accelerated to a normal speed range.

In other words, conventional bicycles have a drawback in that a strong force is required for a running of the bicycle from its stopped state, along with a drawback of a very low instantaneous accelerating velocity.

In particular, such braking devices exhibit an

inefficient braking effect because the braking effect is obtained only by the frictional force generated between the rim and lining.

Disclosure of the Invention Therefore, an object of the invention is to provide a braking device for bicycles which is adapted to store an inertial force of the bicycle wheel generated upon a braking operation for the bicycle and to obtain a thrust for the running of the bicycle from the stored inertial force, thereby achieving an effective braking for the bicycle while enhancing an instantaneous accelerating speed of the bicycle.

In accordance with the present invention, this object is accomplished by providing a braking device for a bicycle having a drive wheel adapted to rotate by a pedaling operation comprising: power receiving means for receiving a rotating force from the drive wheel; rotating force storing means for storing the rotating force received by the power receiving means; direction inverting means for inverting the releasing direction of the stored rotating force from the storing means such that the releasing direction corresponds to the rotating direction of the drive wheel; and drive means connected to the direction inverting means and adapted to transmit the rotating force released from the storing means to the drive wheel.

Brief Description of the Drawings Other objects and aspects of the invention will become apparent from the following description of embodiments with reference to the accompanying drawings in which:

FIG. 1 is a block diagram illustrating a braking device for bicycles according to the present invention; FIG. 2 is a sectional view illustrating a braking device according to a first embodiment of the present invention; FIG. 3 is an elevational sectional view illustrating a portion of the braking device shown in FIG. 2; FIG. 4 is a sectional view illustrating a braking device according to a second embodiment of the present invention; FIG. 5A is a side view illustrating a portion of the braking device shown in FIG. 4; FIG. 5B is a front view illustrating a push lever operatively connected to a brake lever in the braking device of FIG. 4; FIG. 6 is a plan view illustrating a locking member for the brake lever according to the present invention; and FIG. 7 is an exploded perspective view illustrating a braking device according to a third embodiment of the present invention.

Best Mode for Carrying Out the Invention FIG. 1 is a block diagram illustrating a braking device for bicycles according to the present invention.

As shown in FIG. 1, the braking device of the present invention includes a power receiving means 2 for receiving a rotating force from a rotating wheel 1 (FIG. 1), a rotating force storing means 3 for storing the rotating force received by the power receiving means 2, a direction inverting means for inverting the releasing direction of the stored rotating force from

the storing means 3 such that the releasing direction corresponds to the rotating direction of the wheel 1, and a drive means 5 connected to the direction inverting means 4 and adapted to transmit the rotating force released from the storing means 3 to the wheel 1.

The power receiving means 2 may be directly connected to the rotating wheel 1. Alternatively, the power receiving means 2 may be indirectly connected to the rotating wheel 1 via a belt-and-pulley type power transmission means or a clutch type frictional power transmission means.

Preferably, the rotating force storing means 3, which is adapted to store the rotating force transmitted from the power receiving means 2, comprises an resilient spring. In particular, a spiral spring or torsion spring may be used.

The direction inverting means 4 serves to invert the releasing direction of the stored rotating force from the storing means 3 such that the releasing direction corresponds to the rotating direction of the wheel 1. The direction inverting means 4 may comprise a free wheel, a combination of gears or a ratchet gearing.

The drive means 5 serves to transmit the rotating force released from the storing means 3 to the wheel 1.

The drive means 5 may comprises a ratchet directly connected to the wheel 1 in order to achieve an improvement in the power transmission efficiency.

Alternatively, the drive means 5 may comprises a clutch.

Now, various embodiments of the present invention will be described in detail.

[First Embodiment] Referring to FIGS. 2 and 3, a braking device for bicycles according to a first embodiment of the present invention is illustrated. As shown in FIGS. 2 and 3, the braking device of the first embodiment includes a drive pulley 25 fixedly mounted to one end of a hub 14 included in the wheel 1, a hollow driven pulley 27 connected to the drive pulley 25 by means of a belt 26 such that it is driven by a drive force of the drive pulley 25, and an resilient member 30 mounted in the interior of the driven pulley 27 and adapted to perform compression and expansion operations in accordance with the rotating directions of the driven pulley 27. The resilient member 30 is mounted at one end thereof to the inner peripheral surface of the driven pulley 27 and at the other end thereof to a fixed shaft 31 adapted to support the driven pulley 27. A first gear 41 is formed on the outer peripheral surface of the driven pulley 27 at one end of the driven pulley 27. A second gear 42, which engages with the first gear 41, is also provided at the drive pulley 25. The second gear 42 is provided at its inner peripheral surface with a ratchet 51. The ratchet 51 engages with a latchet claw 52 mounted to a hub 25a included in the drive pulley 25. The braking device also includes a belt tensing means 23 operatively connected to a brake lever 21 and adapted to tense the belt 26 in accordance with the operation of the brake lever 21. The belt tensing means 23 includes a cable 22 connected to the brake lever 21, and a lever simply denoted by the reference numeral 23 in FIG. 3 and connected at one end thereof to the cable 22. The belt tensing means 23 also includes a roller 24 mounted to the other end of

the lever. Although only one roller 24 is shown in FIG. 3, the belt tensing means 23 may have two rollers 24 respectively arranged above and beneath the belt 26.

The resilient member 30 may be selected from a variety of resilient members. For example, the resilient member 30 may comprise a spiral spring or torsion spring. Preferably, a locking member 18 is also provided which is adapted to prevent the brake lever 21 from returning from its braking position. By virtue of such a locking member, it is possible to eliminate inconvenience in that it is unnecessary for the user to continuously pull the brake lever 21 even at a stopped state of the wheel 1.

The operation of the braking device having the above mentioned construction according to the first embodiment of the present invention will now be described.

As the user pedals on the bicycle, a rotating force is transmitted to the wheel 1 via a chain 11 and a free wheel 12, thereby causing the bicycle to perform a normal advancing operation. At this state, the belt 26, which serves to connect the driven pulley 27 to the drive pulley 25, is in a loosened state. Accordingly, the belt 26 can not transmit the rotating force of the drive pulley 25 to the driven pulley 27. When the user pulls the brake lever 21 to stop the bicycle, the cable 22 connected to the brake lever 21 is pulled, thereby causing the lever 23 to pivot in a direction urging the roller 24 to depress the belt 26. As a result, the belt 26 is tensed, so that the rotating force of the drive pulley 25 is transmitted to the driven pulley 27, thereby causing the driven pulley 27 to rotate. At this time, the second gear 42 of the drive pulley 25,

which engages with the first gear 41 of the driven pulley 27, rotates in a direction opposite to the rotating direction of the wheel 1. However, the ratchet 51 formed on the inner peripheral surface of the second gear 42 does not engage with the ratchet claw 52 during its rotation. Accordingly, the second gear 42 can not transmit its rotating force to the drive pulley 25.

Since the resilient member 30 is fixedly mounted at one end thereof to the driven pulley 27 and at the other end thereof to the fixed shaft 31, it is wound while being compressed by the rotation of the driven pulley 27. When the resilient member 30 is completely compressed such that it can be compressed no longer, the braking of the wheel 1 is approximately completed.

However, when the drive pulley 25 still rotates even at the completely compressed state of the resilient member 30, the belt 26 slides on the stopped driven pulley 27 while generating a frictional force, thereby completely braking the wheel 1.

When it is desired to maintain the braking state, the locking member 18 is operated to lock the brake lever 21 so that the cable 22 is maintained at its tensed state even when the user releases the brake lever 21. In accordance with the operation of the locking member 18, the belt tensing means 23 continuously tenses the belt 26.

Where it is desired to run the bicycle again, the user pulls the brake lever 21, releases the locking member 18 engaged in a pivoting space of the brake lever 21, and then releases the brake lever 21. When the brake lever 21 is released, the cable 22 is loosened, thereby causing the roller 24 of the belt

tensing means 23 to move away from the belt 26. As a result, the belt 26 is loosened. Accordingly, the driven pulley 27 rotates in a direction opposite to the advancing direction of the bicycle by the resilient force of the resilient member 30 disposed in the driven pulley 27. By this rotation, the second gear 42 engaged with the first gear 41 rotates in the same direction as the advancing direction of the bicycle.

In the case of this rotation of the second gear 42, the ratchet 51 of the second gear 42 engages with the ratchet claw 52, thereby rotating the drive pulley 25.

As a result, the wheel 1 rotates in the advancing direction of the bicycle 1. Thus, a thrust is generated.

[Second Embodiment] Referring to FIGS. 4 to 6, a braking device for bicycles according to a second embodiment of the present invention is illustrated. As shown in FIGS. 4 to 6, the braking device of the second embodiment includes a hollow shaft 301 fitted around a fixed shaft 113 on which the wheel 1 is rotatably mounted. The hollow shaft 301 is provided at one end thereof with a free wheel 511. A drum 213 is fitted around the shaft 301. An resilient member 300 is mounted in the interior of the drum 213. The resilient member 300 is connected at one end thereof to the shaft 301 and at the other end thereof to the inner peripheral surface of the drum 213. A frictional plate 211 is attached to one end of the drum 213. The frictional plate 211 is adapted to come into contact with a disc 111 mounted to the wheel 1, thereby transmitting a rotating force to the wheel 1. A ratchet 412 is formed on the outer

peripheral surface of the drum 213. A ratchet claw 411 is also mounted to a frame 16 of the bicycle. The ratchet claw 411 engages selectively with the ratchet 412, thereby allowing the drum 213 to rotate only in one direction. In order to prevent an overload from being transmitted to the resilient member 300, the drum 213 and shaft 301 are provided, at their ends opposite to the frictional plate 211, with stoppers 215 and 303, respectively. The shaft 301 is provided at its end opposite to the frictional plate 211 with a plurality of engaging grooves 302. A push lever 220 is connected to the cable 22 which is coupled to the brake lever 21.

The push lever 220 pivots in accordance with the pulling operation of the cable 22. The push lever 220 has a stopper 221 adapted to be engaged in a selected one of the engaging grooves 302 of the shaft 301, and a push protrusion 222 adapted to push the drum 213, thereby forcing the frictional plate 211 to come into contact with the disc 111. The push lever 220 is always urged to pivot in a direction that the push protrusion 222 moves away from the drum 213 by a spring 223 (FIG. 5B). In this embodiment, a locking member 18 having the same construction as that of the first embodiment is also provided.

The operation of the braking device having the above mentioned construction according to the second embodiment of the present invention will now be described.

When the user pulls the brake lever 21 to stop the bicycle which runs by the pedaling of the user carried out in a conventional manner, the cable 22 connected to the brake lever 21 is pulled, thereby causing the push lever 220 to pivot in a direction urging the stopper

211 of the push lever 220 to be engaged in an optional one of the engaging grooves 302 provided at the shaft 301. As a result, the shaft 301 stops its rotation.

At the same time, the push protrusion 222 of the push lever 220 pushes one end of the drum 213 toward the disc 111, thereby causing the frictional plate 211 attached to the other end of the drum 213 to come into contact with the disc 111. The frictional plate 211, which comes into contact with the disc 111, rotates by a frictional force generated between the frictional plate 211 and disc 111. Accordingly, the drum 213 rotates in the same direction as the wheel 1. At this time, the shaft 301 is maintained at a stopped state by the stopper 221 of the push lever 220. As a result, the resilient member 300 mounted in the drum 213 is wound in the same direction as the rotation direction of the drum 213 while being compressed by the rotation of the drum 213. Accordingly, the resilient member 300 retains a resilient force. When the drum 213 still rotates even at the completely compressed state of the resilient member 300, the stopper 215 protruded from the drum 213 comes into contact with the stopper 303 protruded from the shaft 301, thereby preventing a further rotation of the drum 213. Accordingly, no overload is subjected to the resilient member 300. The wheel 1 is effectively braked by the frictional force generated between the frictional plate 211 and disc 111 along with the effect of the stoppers 215 and 303 stopping the rotation of the drum 213.

When it is desired to maintain the braking state, the locking member 18 is operated to lock the brake lever 21 so that the cable 22 is maintained at its tensed state even when the user releases the brake

lever 21. In accordance with the operation of the locking member 18, the push lever 220 is maintained at its braking position.

Where it is desired to run the bicycle again, the user pulls the brake lever 21, releases the locking member 18, and then releases the brake lever 21. When the brake lever 21 is released, the cable 22 is loosened, thereby causing the push lever 220 to pivot in a direction that its push protrusion 222 moves away from the drum 213 by virtue of the resilience of the spring 223. As the push protrusion 222 moves away from the drum 213, the frictional plate 211 is separated from the disc 111. As the push lever 220 further pivots, the stopper 221 is disengaged from the engaging groove 302 of the shaft 301. Accordingly, the shaft 301 is in a rotatable state. At this time, the drum 213 can not rotate by the expanding resilience of the resilient member 300 because it is configured to rotate only in the compressing direction of the resilient member 300 by virtue of the ratchet mechanism consisting of elements 411 and 412. Accordingly, the shaft 301 rotates by the expanding resilience of the resilient member 300. In accordance with the rotation of the shaft 301, the free wheel 511 mounted to the shaft 301 rotates, thereby rotating the wheel 1. Thus, a thrust is generated.

[Third Embodiment] Referring to FIG. 7, a braking device for bicycles according to a third embodiment of the present invention is illustrated. As shown in FIG. 7, the braking device of the third embodiment includes a frictional drum 401 fixedly mounted to one end of a hub

14 included in the wheel 1. The braking device also includes an outer drum 405 arranged such that it encloses the frictional drum 401. The outer drum 405 has a ratchet 402 formed on the outer peripheral surface of the outer drum 405, and a band brake 404 mounted to the inner peripheral surface of the outer drum 405. The band brake 404 is connected to a cable 403 coupled to the brake lever. The outer drum 405 is also provided at one end thereof with a protrusion 407 to which one end of a spring 406 is coupled. The inner drum 405 is also provided at the other end thereof with an internal gear 408.

A through hole is formed at the center of the internal gear 408. A shaft 421 included in a rotating direction inverting mechanism 420 extends through the through hole. The other end of the spring 406 is connected to the shaft 421. The shaft 421 is an extension of a shaft on which the hub 14 of the wheel 1 is rotatably mounted.

The rotating direction inverting mechanism 420 includes a plurality of planetary gears 422 engaging with the internal gear 408 of the drum 405, and a sun gear 423 engaging with the planetary gears 422, thereby rotating along with the planetary gears 422. The sun gear 423 is provided at its inner peripheral surface with a ratchet 424. A ratchet claw 425, which is adapted to engage with the ratchet 424, is mounted on the frictional drum 401.

A ratchet claw 411, which is adapted to engage with the ratchet 402 formed on the outer peripheral surface of the drum 405, is also provided to control the rotation of the drum 405. The ratchet claw 411 is connected to a thrust actuating grip (not shown)

mounted on a handle of the bicycle via a cable.

The operation of the braking device having the above mentioned construction according to the third embodiment of the present invention will now be described.

When the user pulls the brake lever to stop the bicycle which runs by the pedaling of the user carried out in a conventional manner, the cable 403 connected to the brake lever is pulled, thereby causing the band brake 404 mounted in the drum 405 to come into contact with the outer peripheral surface of the frictional drum 401. As a result, the rotating force of the frictional drum 401 is transmitted to the outer drum 405.

As the outer drum 405 rotates, the spring 406, which is engaged at its one end with the protrusion 407, is wound in the same direction as the rotation direction of the outer drum 405 while being compressed by the rotation of the outer drum 405. Accordingly, the spring 406 retains a resilient force. The winding operation of the spring 406 is enabled in that the shaft 421, to which the other end of the spring 406 is mounted, is fixedly mounted to the frame of the bicycle.

When the outer drum 405 rotates about 270° (about 3/4 of one revolution), the protrusion 407, to which one end of the spring 406 is connected, comes into contact with an edge of the bicycle frame, so that the outer drum 405 rotates no longer. During the rotation of the outer drum 405, the cable 403 is also wound around the outer drum 405.

Since the cable 403 is received in a tube while having a sufficient extra length, the cable can be

wound around the outer drum 405 while being pulled.

Such a principle of the cable is the same as that of conventional bicycle brake cables.

When the hub 14 of the wheel 1 still rotates even in the state in which the protrusion 407 comes into contact with the bicycle frame, thereby causing the outer drum 405 to rotate no longer, a frictional force is generated between the band brake 404 mounted in the outer drum 405 and the frictional drum 401 as the band brake 404 slips on the frictional drum 401. By this frictional force, a braking is accomplished. Such a braking operation is the same as those in conventional braking devices for bicycles.

When the user releases the brake lever in the above mentioned state, the cable 403 is released, thereby causing the band brake 404 to move away from the frictional drum 401. Accordingly, the hub 14 of the wheel 1 is in a state in which it can freely rotate in the advancing direction of the bicycle. In other words, the bicycle can run in this state. However, the outer drum 405 is maintained in a stopped state while retaining the resilient force of the spring because the ratchet 402 of the outer drum 405 is still engaged with the rachet claw 411.

When the user pulls again the brake lever during the running of the bicycle in the above mentioned state, in order to reduce the running speed of the bicycle or to stop the running bicycle, the cable 403 pulls the band brake 404, thereby causing the band brake 404 to come into contact with the frictional drum 401. As a result, the outer drum 405 tends to rotate.

However, the outer drum 405 can not rotate because the protrusion 407 is in a state engaged with the bicycle

frame. In this state, accordingly, the speed reduction and braking are achieved by the frictional force generated between the frictional drum 401 and band brake 404.

On the other hand, where it is desired to obtain a thrust of the bicycle, the thrust actuating grip (not shown) mounted on the handle of the bicycle is pivotally operated by an appropriate manipulation of the user to pull the cable connected between the actuating grip and ratchet claw 411. As the cable is pulled, the ratchet claw 411 is disengaged from the ratchet 402 of the outer drum 405, so that the outer drum 405 rotates in a direction opposite to the advancing direction of the bicycle by virtue of the resilience of the spring 406. At the same time, the planetary gears 422 engaging with the internal gear 408 of the outer drum 405 also rotates in a direction opposite to the advancing direction of the bicycle.

As a result, the sun gear 423 rotates in the same direction as the advancing direction of the bicycle.

At this time, the ratchet 424 internally formed on the sun gear 423 rotates without being interfered by the ratchet claw 425 mounted on the frictional drum 401.

Thus, a thrust is obtained.

In this case, a damper may be provided at power transmission means associated with the internal gear 408 and the frictional drum 401 to absorb an impact generated due to an abrupt power transmission.

In accordance with the third embodiment of the present invention having the above mentioned configuration, it is possible to selectively obtain a thrust from an inertial force generated and stored upon a braking operation.

As apparent from the above description, the present invention provides a braking device for a bicycle which is capable of obtaining a thrust from an inertial force of the bicycle wheel generated upon a braking operation for the bicycle. Accordingly, it is possible to achieve an effective braking for the bicycle while enhancing an instantaneous accelerating speed of the bicycle.

Although the preferred embodiments of the 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 disclosed in the accompanying claims.