PARKING BRAKE FOR A TWO WHEELER

FIELD OF THE INVENTION

[0001] The present subject matter relates generally to brakes, and particularly to a means for locking a brake lever in a two wheeled vehicle.

BACKGROUND OF THE INVENTION

[0002] A two wheeled saddle type vehicle moving unexpectedly from rest may cause injuries. Hence, a parking brake is provided in the vehicle to arrest the movement of wheels so that the vehicle remains at rest even when parked on a slope. In a conventional parking brake system, a hand operated parking brake lever is swingably integrated with a brake lever. The brake lever, mounted on a steering handle, is further connected to a drum brake through a brake cable. Such parking brake lever has to be operated with one hand for locking the brake lever in a particular position in order to prevent the rotation of the wheel. However this system presents a few disadvantages.

[0003] In the prior art, the parking brake lever is capable to lock the brake lever in only one position. However, over a period of time, the brake shoes in the drum brake start wearing out. If this wear is more than the leverage gained by the operative parking brake lever, the brake shoe fails to sufficiently engage with the brake drum and therefore the parking brake system is insufficient to hold the vehicle at rest. In these circumstances, the parking brake system may either reduce in efficiency or become completely ineffective depending upon the extent of such wearing. Moreover, the releasing of a locked conventional parking brake lever to an unlocked condition usually involves both the hands and hence is bothersome for an operator of the two wheeled saddle type vehicle.

[0004] The present subject matter addresses all or any of the above problems and obviate the lacunae in the prior art. It is thus an object of the present subject matter to disclose a means competent to function as a parking brake lever and capable of locking a brake lever in a cable operated brake system for a saddle type vehicle even during a brake shoe wear condition. It is another object of the present subject matter to provide a simply constructed and easy to use parking brake system capable to operate in at least two brake lever positions. It is yet another object of the present invention to provide a reliable and efficient parking brake system which is minimally dependent on the brake shoe condition.

SUMMARY OF THE INVENTION

[0005] To this end, the present subject matter discloses a parking brake system for a saddle type two wheeled vehicle comprising: a brake lever, the brake lever further comprising a groove at a lower surface facing toward the ground, the said groove including at least two slots, a first slot and a second slot; a means competent to function as a parking brake lever, the said means including at least two ends namely a first end and a second end, whereby the first end of the said means is configured to lock the said brake lever in an engaged position on attachment of the first end with the said groove of the said brake lever and the second end actuates the first end on being thumb operated by an operator of the said two wheeled vehicle. The said means is retractable to its original position and is secured to the handle bar along with the brake lever.

[0006] According to an aspect of the present subject matter, when a brake shoe is in the brake shoe normal condition and the brake lever is pulled toward the hand grip, a projection in the first end of the said means, on being operated, fits into the first slot of the said groove to lock the said brake lever, and when the brake shoe is in brake shoe wear condition and the brake lever is further pulled towards the hand grip, the said projection of the said means fits into the second slot of the said groove to lock the said brake lever.

[0007] According to another aspect of the present subject matter, the parking brake system is operable during a brake shoe normal condition and a brake shoe wear condition and hence is operable for two different brake lever positions.

[0008] According to yet another aspect of the present subject matter, the parking brake system is preferably used with a cable operated brake system for engaging a rear wheel.

[0009] According to a further aspect of the present subject matter, the caliper cover can be used with a rear disc brake system provided in any saddle type vehicle including a motorcycle, moped and a scooter type motorcycle.

[00010] The foregoing objectives and summary provide only a brief introduction to the present subject matter. To fully appreciate these and other objects of the present subject matter as well as the subject matter itself, all of which will become apparent to those skilled in the art, the ensuing detailed description of the subject matter and the claims should be read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[00011] The above and other features, aspects, and advantages of the subject matter will be better understood with regard to the following description, appended claims and accompanying drawings where:

Figure 1 shows a side view of a parking brake system according to a first embodiment of the present subject matter.

Figure 2 shows a bottom view of the parking brake system according to the first embodiment of the present subject matter.

Figure 3 shows a front view of the parking brake system according to the first embodiment of the present subject matter.

Figure 4 shows a perspective view of the parking brake system according to the first embodiment of the present subject matter.

Figure 5 shows a rear perspective view of the parking brake system according to the first embodiment of the present subject matter.

Figure 6 shows a bottom view of the parking brake system according to a second embodiment of the present subject matter in a brake shoe normal condition.

Figure 7 shows a bottom view of the parking brake system according to the second embodiment of the present subject matter in a brake shoe wear condition.

DETAILED DESCRIPTION OF THE INVENTION

[00012] A parking brake system maintains a vehicle brake system in an engaged position when the vehicle is in the stopped condition, whether the engine is on or off, and whether the vehicle is attended or unattended by an operator of the vehicle. It is to be noted that the parking brake is not altogether a new braking system in the vehicle. In fact the existing brake system is configured to act as the parking brake when fitted with the means competent to function as a parking brake lever.

[00013] If a brake shoe in the vehicle brake system is in normal condition, the brake shoe to brake drum contact is adequate i.e. the brake shoe is sufficiently able to engage with the brake drum. However over a period of time when the brake shoe starts wearing out, a greater effort is sought on a brake lever to pull it towards the hand grip in order to develop the required brake shoe to brake drum contact. In this condition, the swivel of the brake lever increases and the distance between the brake lever and the hand grip in the brake engaged position decreases. The brake lever when locked in this condition by the parking brake lever fails to provide sufficient braking contact pressure to keep the vehicle at rest. The vehicle may thus move on its own leading to serious ramifications.

[00014] The present subject matter overcomes this problem by providing a parking brake system in a cable operated brake system for a two wheeled saddle type vehicle which is now described in detail in connection with the rendered figures 1-7. The detailed explanation of the constitution of parts other than the subject matter which constitutes an essential part has been omitted at suitable places. The parking brake system includes a means competent to function as a parking brake lever and capable of locking a brake lever during a 'brake shoe normal condition' as well as a 'brake shoe wear condition'. The brake shoe normal condition refers to a brake shoe which engages effectively with a brake drum without imparting extra pressure on the brake lever. The brake shoe wear condition refers to a brake shoe which wears out over a period of time and effectively engages with the brake drum only when extra pressure is imparted on the brake lever.

[00015] Typically, the brake lever may be hand actuated or pedal actuated. However the scope of the present subject matter is limited to a hand actuated brake lever which is further connected to a brake drum through cables. Further, the foregoing drawings embody the present subject matter through a left hand operated rear wheel brake lever, but it can also be used with a right hand operated front brake lever with required modifications within the scope of the subject matter. It is also to be noted that in the foregoing description, a "saddle type vehicle" includes, besides a vehicle driven by an operator straddling the saddle, a scooter type vehicle driven by the operator seated with his or her legs close together as well as a scooter type vehicle having a step through space.

[00016] Further, "front" and "rear", and "left" and "right" referred to in the ensuing description of the illustrated embodiment refer to front and rear, and left and right directions as seen in a state of being seated on a seat of the saddle type vehicle. Furthermore, a longitudinal axis refers to a front to rear axis relative to the vehicle, while a lateral axis refers generally to a side to side, or left to right axis relative to the vehicle. Various other features and embodiments of the parking brake system according to the present subject matter here will be discernible from the following further description thereof, set out hereunder.

[00017] Figures 1-5 illustrate a first embodiment of the parking brake system according to the present subject matter. It broadly comprises a brake lever 10 secured to a handle bar 9 and a means 30 secured to the handlebar 9 competent to function as a parking brake lever. In the description, this 'means' would be referred to as 'parking brake lever' for ease of understanding. The brake lever 10 is used to operate a rear wheel brake drum (not shown) through a brake cable and is mounted on the handle bar 9 with a typical known clamping mechanism. In an embodiment of the present subject matter, the brake lever 10 is mounted to the handle bar 9 by a flange 12 so that it can pivot about a support pin.

[00018] The brake lever 10 is capable of moving relative to a hand grip 20 from a disengaged position to an engaged position and from the engaged position to the disengaged position, but normally remains biased to the disengaged position. The tubular hand grip 20 is mounted on the outer end portion of the handle bar 9. In the brake disengaged position, the brake lever 10 is transverse to the longitudinal axis of the hand grip 20. It can be shifted higher or lower on the handle bar 9 depending on the needs and comfort of the operator and allows the operator to brake in a controlled and sustained manner. The brake lever 10 further comprises a groove 11 at a lower surface facing toward the ground. The groove 11 includes at least two slots, a first slot A and a second slot B as shown in Figure 2.

[00019] Moreover, the parking brake lever 30 is pivotally supported and spring operated. The parking brake is required when an operator intends to brake the vehicle, when at rest, without having to apply and hold the brake lever continuously for the intended duration. The operation of the parking brake lever 30 precludes the vehicle from moving on its own when parked, for example, on a slope. Figure 1 shows a clear view of the parking brake lever according to the first embodiment. The parking brake lever 30 includes at least two ends, namely a first end 35 and a second end 34, wherein the first end 35 is configured to lock the brake lever 10 in the engaged position on attachment of the first end 35 with the said groove 11 of the brake lever 10 and the second end 34 actuates the first end 35 on being thumb operated by an operator of the two wheeled vehicle. The first end 35 is disposed near to the brake lever 10 whereas the second end 34 is disposed far from the brake lever 10.

[00020] The parking brake lever 30, at its first end 35, further comprises at least one retractable projection 31 acting as a hook to lock the brake lever 10 in the engaged position. The projection 31 at the first end of the parking brake lever is designed to operate for two different rear wheel brake lever positions i.e. during brake shoe normal condition and during brake shoe wear condition. It is to be noted that in both the brake lever positions, the brake drum is engaged. However it is less effective during the brake shoe wear out condition. When in operation, the projection 31 is fortified into the groove 11 in one of its slots, depending upon the brake shoe condition, to lock the brake lever in engaged position. The slots A and B are separated from each other in such a way that at a time the projection is fortified within one slot only and does not slip into the other slot. The parking brake lever 30 is secured to the handle bar 9 by at least one holder 33 hanging normally to the ground as shown in Figure 3. Further, Figure 3 shows a front view of the parking brake system according to the first embodiment while Figure 5 shows a rear perspective view of the parking brake system according to the first embodiment.

[00021] According to an aspect, the parking brake lever 30 is connected to the handle bar 9 and swingably integrated with the brake lever 10 with the help of a torsion spring 32.

[00022] The functioning of the parking brake system is now described. During normal braking (during brake shoe normal condition and when the parking brake lever is inoperative), the operator wraps the hand grip 20 with his palm and thumb for support and engulfs the brake lever 10 with his four fingers. The operator then conveniently compresses the brake lever 10 towards the hand grip 20 on the handle bar. assembly in order to engage the brake shoe with the brake drum and holds it in this position. This operation generates a braking force on the rear wheel for stopping the vehicle. The brake lever is now in engaged position. The brake lever is free to operate at operator's demand without any interference from the parking brake lever 30 in normal braking conditions when the vehicle is in motion.

[00023] The second end 34 of the parking brake lever 30 is then swung, by use of a left thumb, away from the operator so that the first end 35 of the parking brake lever 30 comprising the projection 31 moves upwards and fits into the slot A of the groove 11 in the hand-held brake lever 10. This is shown in Figure 2. Now the brake lever 10 is in parking mode and the torsion spring 32 ensures that the parking brake lever 30 remains in this position. To release the parking brake lever, the brake lever 10 is pulled further towards the hand grip 20 with the help of fingers. The torsion spring 32 causes the projection 31 to be released from slot A and retract to the original position. In this way the present invention provides an easy release of the parking brake from a locked condition to an unlocked condition with minimal effort by the operator and without the use of the second hand.

[00024] In the brake shoe wear condition, the brake lever 10 is to be further compressed towards the hand grip 20 to engage the brake drum effectively. The second end 34 of the parking brake lever 30 is then pushed away from the operator to operate the parking brake lever 30 due to which the projection 31 now fits into second slot B of the groove 11 since slot A has moved from its earlier position due to additional rotation of the brake lever 10. In this way second slot B is used to get additional leverage to lock the brake lever in the engaged position. The operation of brake lever 10 and parking brake lever 30 in brake shoe wear condition is similar to the previous position except that the brake lever 10 needs to be further compressed toward the handle bar 9.

[00025] The first slot A and second slot B in the groove 11 may be at the same depth in one embodiment of the present invention but separated from each other. However in another embodiment of the present subject matter, one of the slots, preferably second slot B, can be at a greater depth than the slot A. The additional depth avoids slippage of the projection 31 from the respective slot and thus prevents failure of the parking brake when the vehicle is parked on a slope. Further, the brake lever 10 may be manufactured by aluminium die casting. The groove slots in conjunction form the shape of a rectangle to ensure firm locking while making the casting defect-free.

[00026] In a second embodiment of the present subject matter, the same function of the parking brake can be achieved by providing leverage in the projection of the parking brake lever itself rather than providing it on the brake lever. Figure 6 shows a bottom view of the parking brake system according to a second embodiment of the present subject matter in a brake shoe normal condition. Here, the groove 11 at the lower surface of the brake lever 10 facing the ground comprises a single slot A (preferably rectangular) and the projection 31 at the first end 35 of the parking brake lever 30 is bifurcated into two projections 31a, 31b placed one behind the other. The two bifurcated projections are spaced from each other in such a way that during brake shoe normal condition, only one of the projections 31a fits into the slot A of the groove 11. On the other hand, during the brake shoe wear condition, the additional leverage for locking the brake lever 10 is provided by the other projection 31b and both the projections 31a, 31b fit into the groove 11 when the brake lever 10 is further pulled towards the hand grip 20 to engage the brake drum. Figure 7 shows a bottom view of the parking brake system according to the second embodiment of the present subject matter in a brake shoe wear condition. The second embodiment precludes the manufacturing difficulty in the brake lever 10.

[00027] Further, the parking brake lever 30 to lock the brake lever 10 may be directly or indirectly mounted to the handlebar 9. In an embodiment of the present invention, the parking brake lever 30 is indirectly attached to the handlebar 9 by means of the holder 33 and is spring loaded. The parking brake lever 30 is pivotable about a pin 36 as shown in Figure 4 and is mounted on an inner surface of the holder 33. The holder 33 in turn is attached to the handle bar 9. The parking brake lever 30 is capable to retract to its original position by the torsion spring 32. This mounting mechanism allows ease of operability of the parking brake lever by an operator of the vehicle. The operation is not hampered by the brake cables lying around. In another embodiment of the present subject matter, the parking brake lever 30 comprising the projection 31 is directly mounted on the handlebar 9 as shown in Figure 6 with the help of a clamp and is spring loaded.

[00028] According to an aspect, the position of the slot(s) in the lower surface of the brake lever, facing the ground, depends on the brake shoe normal condition and brake shoe wear condition. The slots are positioned so that even during the brake shoe wear condition, the brake drum effectively engages itself with the wheel on operation of the brake lever. Further, the present parking brake system is preferably usable with the cable operated brake system for engaging a rear wheel of the two wheeled vehicle.

[00029] The present subject matter and its equivalent thereof offer many advantages, including those which have been described henceforth. The parking brake system is capable to operate in at least two brake lever positions and is minimally dependent on the brake shoe condition. The parking brake lever is positioned to be operated by a thumb to reduce the strain felt by the operator and increase the convenience. On the contrary, any operation by a forefinger causes more pain. Further, the reliable locking of the brake lever even in brake shoe wear condition helps in trouble-free parking of the two wheeled vehicle on a slope and increasing the safety.

[00030] Furthermore, since the operator needs to move his or her thumb over a short distance to push the parking brake lever to cover both the brake shoe conditions, the operability and efficiency of the parking brake system is increased. The locked brake lever cannot be unlocked unless the operator pulls the brake lever towards the hand grip with the objective of disengaging the brake drum. Hence the present subject matter also provides ease of recognition of the locked state of the parking brake lever. Additionally, the parking brake system can be easily retrofitted on an existing vehicle with minor modifications, including change of brake lever and mounting of the parking brake lever.

[00031] The present subject matter is thus described. The description is not intended to be exhaustive nor is it intended to limit the invention to the precise form disclosed. It will be apparent to those skilled in the art that the disclosed embodiments may be modified in light of the above description. The embodiments described are chosen to provide an illustration of principles of the invention and its practical application to enable thereby one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. Therefore the forgoing description is to be considered exemplary, rather than limiting, and the true scope of the invention is that described in the appended claims.

We claim:

1. A parking brake system in a cable operated brake system for a two wheeled vehicle comprising:

a brake lever secured to a handle bar, the said brake lever capable of moving relative to a hand grip from a disengaged position to an engaged position and from the engaged position to the disengaged position,

the said brake lever further comprising a groove at a lower surface facing toward the ground, the said groove including at least two slots, a first slot and a second slot,

a means secured to the said handlebar competent to function as a parking brake lever, the said means including at least two ends namely a first end and a second end, whereby the first end of the said means is configured to lock the said brake lever in the engaged position on attachment of the first end with the said groove of the said brake lever and the second end actuates the first end on being thumb operated by an operator of the said two wheeled vehicle,

wherein the said parking brake system is operable during a brake shoe normal condition and a brake shoe wear condition.

2. The parking brake system as claimed in claim 1, wherein the said first slot and the said second slot of the said groove are separated from each other in such a way that at a time, the said projection is fortified within one slot only.

3. The parking brake system as claimed in claim 1 or claim 2, wherein the said means comprises at its first end, at least one retractable projection acting as a hook, the said retractable projection adapted to fit into one of the said slot of the said groove of the brake lever, the said means capable to retract to its original position when the said brake lever is released; whereby when a brake shoe is in the brake shoe normal condition and the brake lever is pulled toward the hand grip, the said projection of the said means on being operated fits into the first slot of the said groove to lock the said brake lever, and when the brake shoe is in brake shoe wear condition and the brake lever is further pulled towards the hand grip, the said projection of the said means fits into the second slot of the said groove to lock the said brake lever.

4. The parking brake system as claimed in claim 1, wherein the said means is secured to the handle bar by a holder.

5. A parking brake system in a cable operated brake system for a two wheeled vehicle comprising:
a retractable parking brake lever, a first end of the said parking brake lever comprising of at least two spaced projections one behind the other,

a brake lever secured to a handle bar, a groove at a lower surface of the said brake lever facing towards the ground comprising at least one slot configured to accept the said projections of the parking brake lever,

whereby when a brake shoe is in a brake shoe normal condition and the brake lever is pulled towards a hand grip, one of the projections in the parking brake lever fits into the said slot of the said groove to lock the brake lever; and when the brake shoe is in a brake shoe wear condition and the brake lever is further pulled towards the hand grip, the other projection in the parking brake lever fits into the said slot of the said groove to lock the said brake lever.

6. The parking brake system as claimed in claim 5, wherein the said parking brake lever is secured to the handlebar by a holder and is retractable by means of a torsion spring.

7. The parking brake system as herein described and illustrated by the accompanying drawings.