Brake System

Field of the Invention:

This invention relates to "Brake System". In particular this invention relates to front and rear combined brake system for two-wheeled vehicle.

Background of the Invention:

In most of the present two wheeler braking systems, both front and rear brakes are independently operated i.e. application of front brake force will activate only front wheel brake and rear brake force will activate only rear wheel brake. Rear brake force application is limited, because of dynamics of vehicle during braking. Due to load transfer to front wheel during braking, further increase in rear brake force will result in skidding rather than stopping the vehicle. Vehicle controlling becomes difficult and stopping distance will be more, thereby resulting in poor braking performance due to wheel skidding. So typically in a combined or interlink brake system the available braking force is completely utilised by distributing it to front and rear brake, thereby the stopping distance is minimized in two wheelers. As disclosed in JP2004352181 the interlocking brake device ( or combined braking system), has an interlocking brake manipulating cable which is connected to an intermediate portion of an equalizer lever, which forms a front wheel brake manipulating end portion at one end portion thereof and a rear wheel brake manipulating end portion at another end portion thereof, either one of the front brake cable and the rear brake cable is formed as one independent brake manipulating cable which is connected to an independent brake manipulating member, an engaging member which is capable of being engaged with and being disengaged from the equalizer lever is mounted on the independent brake manipulating cable. In this brake system arrangement, the equalizer lever can tilt towards the wall and hit the spring placed around it. This tilting can lead to mechanism lockage. And during this lockage the front brake application is not possible. Since one spring is used to retain the equalizer in its original position, much brake force is wasted to move the equalizer against the spring. The provision of engaging member resting on equalizer lever slot which is an integral part of the brake cable for sliding and relative rotation is subject to wear and tear for continuous rubbing and sliding inside the slot. To replace the said engaging member the entire cable has to be changed.

In another patent JP9058434 which discloses a longitudinal interlocking brake (or combined brake) practicable through a structure by applying a mechanism, which generates only rear wheel brake force in an early time of brake operating input, but as the brake operating input exceeds a prescribed value, it can generate braking force even at the front wheel. In the above said mechanism there is one input and two output for which the independent lever mechanism is placed longitudinally opposite to the combined lever mechanism, thereby during rear brake application, front brake activation line length is more. The problem associated with this is that it is incapable of providing good brake feel. Since there is only one input, the equalizer lever is not supported and guided during brake operation. At the end of rear brake application, application of the front brake will result in tilting of equalizer lever thereby hitting the wall.

In another patent JP2000309294 which discloses a interlocking brake system (or combined brake system) having an equalizer lever accommodated inside an equalizer case disposed near a head pipe, where a first input cable is connected to an interlocking brake lever which is axially supported at one end of a steering handle and is connected to a mid portion of the equalizer lever. Further a first output cable and a second output cable connected to a rear wheel brake and a front wheel brake are connected to a first end and a second end of the equalizer lever. In this kind of arrangement there is no support /guiding system for front brake circuit (i.e.; is not guided). During rear brake operation, the resultant thrust coming on pin joint of intermediate arm can make front brake circuit to deflect in lateral direction of the cable. This results in mechanism lockage and rubbing of front brake wire with casing walls. The other disadvantage is front brake input cable end is free to slide in the slot due to improper guiding of the joint member the front brake input cable end may bend. For which more rear brake activation force is required during interlocking braking. Even the brake cable wire endpin rotation is not allowed inside that slot. Unnecessary work is also done against the spring which is used in the front brake circuit for initiation for interlocking brake.

In fact in all the known combined brake system arrangement principally the front and rear output are in the same direction or same side thereby rendering restrictions and problems for cable routing

Hence the objective of the present invention is to overcome the above problems associated with the prior arts.

Summary of the Invention:

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

An object of the present Invention is to provide a combined brake system for two wheeled vehicle which provides better dynamics and safety.

Another object of the present invention is to provide a combined brake system for two wheeled vehicle where the brake circuits are guided properly thereby improving the braking feel.

Another object of the present invention is to provide a combined braking system for two wheeled vehicle where the brake cable wire bending is avoided.

Another object of the present invention is to provide a combined braking system for two wheeled vehicle which will minimize the length of cable routing.

Yet another object of the present invention is to provide a cost effective arrangement for combined brake system.

Further object of the present invention is to provide a combined brake system with reduced part counts.

Further object of the present invention is to provide a combined brake system which renders easy packaging for the two wheeled vehicle.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

Brief Description of the Drawings:

The present invention will become more fully understood from the detailed description given herein below 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 conventional scooter type motorcycle.

FIG. 2 shows brake system according to one of the embodiment of the present invention.

Detailed Description of the Invention:

One or more embodiments of the invention provide a combined brake system which can adjust brake forces of front and rear wheels in such a manner that an optimum brake characteristic can be obtained.

The present invention relates to combined braking system for a two wheeled vehicle. For the purpose of illustration a scooter of the general type is illustrated for the application. Referring to figure 1, Referring to figure 1, a front wheel, 2 denotes a front fork, 3 denotes a front fender, 4 denotes a front cover, 5 denotes a leg shield made of resin or metal, 6 denotes a handle bar cover, 7 denotes a headlight, 8 denotes a handle bar ,17 denotes a rear fender and 18 denotes tail lamp.

The center of the body forms a low floor board 9 for functioning as a part for putting feet and a under cowl 10 which is located below the rider's seat and covers at least a part of the engine. The under cowl is made up of metal or resin. The under cowl is hinged to the seat 11. A utility box 12 opens from the rear end to hinged portion. The utility box 12 is provided under the seat extending longitudinally of a vehicle body and the inside of the utility box has a large capacity so that a large article can be housed. A main frame 14 extended along the center of the body before and behind and made of a metallic pipe and is provided under the floor board 9. A swing type power unit 13 is coupled to the rear end of the main frame 14.

A rear wheel 15 is supported on one side of the rear end of the swing type power unit 13. The swing type power unit 13 is suspended in the rear of a body frame.

The side covers 16 both on left and right sides, covers the utility box 12 and other • parts of the vehicle, thereby providing a good appearance to the vehicle.

According to the invention, a combined brake system for two wheeler actuating both front and rear brakes comprises a first braking force distribution mechanism 201 and a second braking force distribution mechanism 202, wherein one output of first braking force distribution mechanism 201 is fed as one input for the second braking force mechanism 202.

According to one of the embodiments of the present invention and referring to figure 2, the said first braking force distribution mechanism 201 is housed in a casing 103. The said casing 103 is mounted on the handlebar 1L in between the two following two planes which are parallel to the ground and passing through control lever assembly and head pipe top surface. Input cable 105 from left side control lever is connected to midway portion of the distributing lever 104 through supporting wall of the casing 103. Output cables 107,106 from the distributing lever 104 are supported by the said casing walls 103 and are connected to either ends of the said distributing lever 104 in the casing 103. One of the said output cable 106 is connected to rear brake system to activate the rear brake.

The second braking force distribution mechanism 102 is placed in a housing 108 which is further mounted below the first braking force distribution mechanism casing 103 and on the head pipe 102. In said housing 108 a grooved wheel 11;5 is provided on which a cable/rope 116 is wrapped around the grove. A lever 117 is connected to the grooved wheel centre by a pin 119. The said pin 119 makes the revolute joint between the grooved wheel 115 and the said lever 117 at centre of the said grooved wheel 115. At least two brackets (111,110) are mounted in the said housing 108 wherein the longitudinal axes of the brackets are tangent to the said grooved wheel 115 at both sides. At least two sliding pin assembly (112,113), having pin holders at both ends are provided (112a,112b,113a,113b) . The Sliding pin assemblies (112,113) can slide in the respective brackets (110,111). The cable 116 wraps around the grooved wheel 115 and connects the pin assemblies (112,113) by sliding pins respectively. The input cable 109 from right hand side control lever is connected to the sliding pin assembly 113 with respective pin 13a. The output cable 107 which is from first brake braking force mechanism 101 is connected to the sliding pin assembly 112 with pin 12a. The said sliding pin assemblies (112,113) can slide in longitudinal direction of the brackets (110,111) respectively. The output cable 120 which is from the centre of the said grooved wheel 115 is connected to the front brake system to activate the front brake.

At the assembly condition i.e. when there is no activation of control levers, both gaps (LI, L2) between the two pins (112,113) and its respective followed brackets (110,111) are kept zero. Activation of the left side control lever will pull the distributing lever 104. The movement of the distributing lever 104 further pulls the said output cables (107,106) from the distributing lever. The force distribution between the said output cables (107,106) is controlled by the position of the input cable 105 from brake lever connection on the distributing lever 104. One of the output cables 107 which is connected to the second braking force distribution mechanism 102 pulls the respective pin assembly t12 wherein the said pin assembly 112 slides in the respective bracket 110 to further pull the cable 116 wrapped around the grooved wheel 115. The said cable 116 second end is connected to other pin 113b in other pin assembly 113 which is rested on the other bracket. The said cable 116 pulls the grooved wheel 115 which further pulls the lever 117 connected to the centre of the grooved wheel 115 to activate the output cable 120 which actuates the front brake. During this operation the gap L2 between the first input (which is from the front brake control lever) pin and respective bracket is zero and the gap LI between the second input (which is from the first brake force distribution mechanism) pin and respective bracket will increase from zero.

The activation of the right side control lever will pull the first input cable 109 which further pulls the respective pin assembly 113 that slides on the respective bracket 111. During this the cable 116 around the wheel 115 is supported by the pin (which connects the second input) and respective bracket on that side. During this the said grooved wheel 115 is pulled which further pulls the output cable 120 to activate the front brake system.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the claims.

We Claim:

1. A combined brake system for two wheeler actuating both front and rear brakes comprising:

a first braking force distribution mechanism; and

a second braking force distribution mechanism;

wherein one output of first braking force distribution mechanism is fed as one input for the second braking force mechanism.

2. The combined brake system as claimed in claim 1, wherein the said first braking force mechanism comprises:

a input from one brake control lever;

a distributing lever, to which the input from brake control lever is connected;

and

at least two outputs from the distributing lever.

3. The combined brake system as claimed in claim 1 and 2, wherein the said first braking force mechanism is housed within a casing and is mounted on the handle bar in the vicinity of the head pipe.

4. The combined brake system as claimed in claim 2, wherein the said input from the brake control lever is connected to the midway portion of the distributing lever.

5. The combined brake system as claimed in claim 1, wherein the said second braking force mechanism comprises:

first input from brake control lever;

second input from the first braking force mechanism output; at least one grooved wheel, over which a cable is wrapped; at least one lever connected to the centre of the grooved wheel by means of a pin to actuate one brake upon pulling;

at least two brackets, wherein the longitudinal axes of the brackets are tangent to the grooved wheel; and

at least two sliding pin assembly, which slides in the brackets and the cable wrapped around the wheel is connected to it through pins; wherein the second braking force mechanism is placed inside a housing and is located on the head pipe. 6. A brake system substantially as shown and described in the specification.