Description:TECHNICAL FIELD
[0001] The present subject matter generally relates to a braking system for vehicles, and more particularly, but not exclusively, to an automatic free play adjuster mechanism in such braking systems.

BACKGROUND
[0002] Generally, two major types of brake systems are used in vehicles, viz. a disc brake system and a drum brake system. The drum brake systems are being used for a long time because of its reliability and its cost-effectiveness. However, there is shift from drum brake systems to disc brake system as the engine capacity and vehicle speeds are increasing, there is a need for effective braking.
[0003] Still, the drum brake systems are used in vehicles with low-speed applications. For example, drum brake system is used in two-wheeled and three-wheeled vehicles, which run at low speeds. The drum brake system comprises a brake drum and at least one brake shoe provided with frictional liner that engages with an inner surface of the brake drum. Either mechanical or hydraulic mechanism is used for actuating the brake for making the liner of the brake shoe to come in contact with the brake drum. Upon actuation, the liners of the brake shoe come in contact with the drum and the frictional contact between the brake shoe and the inner wall of brake drum reduces the rotational speed of the wheel.
BRIEF DESCRIPTION OF DRAWINGS
[0004] The detailed description is described with reference to the accompanying figures, which is related to a two-wheeled vehicle being one embodiment of the present subject matter. However, the present subject matter is not limited to the depicted embodiment(s). In the figures, the same or similar numbers are used throughout to reference features and components.
[0005] Fig. 1 illustrates a left side view of an exemplary two-wheeled motor vehicle, in accordance with an embodiment of the present subject matter.
[0006] Fig. 2 depicts a brake drum assembly, in accordance with the embodiment depicted in Fig 1.
[0007] Fig. 3 illustrates position of brake liner and brake drum liner at normal brake position when the brake is inoperative.
[0008] Fig. 4 illustrates position of brake liner touching the brake drum liner when the brake is pressed normally by a user.
[0009] Fig. 5 illustrates position of brake liner touching the brake drum liner during free play.
[00010] Fig.6 illustrates position of brake liner compressing the brake drum liner when the brake is over pressed by the user.
[00011] Fig. 7 illustrates position of brake liner touching the brake drum when the brake is releasing by the user.
[00012] Fig. 8 illustrates the position of brake liner away from the brake drum liner when the brake is completely released by the user.
[00013] Fig.9 illustrates position of one or more pinion gear with the one or more racks at the start of free play.
[00014] Fig. 10 illustrates position of one or more pinion gear with one or more racks during over pressing of brake.
[00015] Fig. 11 illustrates position of one or more pinion gears with one or more racks during release of brake.
DETAILED DESCRIPTION
[00016] Various features and embodiments of the present subject matter here will be discernible from the following further description thereof, set out hereunder.
[00017] Generally, in vehicles a brake system is used either to slow down or to stop the moving vehicle. In two-wheeled or three-wheeled vehicles, a drum brake system is used as at least one of the braking systems. The drum brake system is installed on either a front wheel or a rear wheel or on all the wheels of the vehicle. Conventionally, a rear wheel is installed with a drum brake system and the users are habituated to actuate the rear wheel brake. This makes the rear brake an essential active safety feature of the vehicle, which is the drum brake system.
[00018] Typically, the drum brake includes a brake drum having inner wall that surrounds the brake shoes. The inner wall is the inner circumferential wall of the brake drum. When the brake is actuated, the liners of the brake shoes come in contact with the inner wall of the brake drum. Frictional forces acting between the brake shoes and the brake drum surface will slow down the rotation of the wheel and eventually bring the wheel to a stop.
[00019] A drum brakes are a brake system with brake drums (rotor) which rotate with the wheels. Inside each drum are brake shoes coated with brake linings (friction material). With this system, friction is generated by pressing the brake shoes against the inside surfaces of the drums. This friction converts kinetic energy into thermal energy. When the brake is actuated, the liners of the brake shoes come in contact with the inner wall of the brake drum. Frictional forces acting between the brake shoes and the brake drum surface will slow down the rotation of the wheel and eventually bring the wheel to a stop. Drum rotation helps to press the shoes and the lining against the drum with more force, offering superior braking force.
[00020] Conventionally, in any known mechanical cam operated drum brake system, specially in 2-wheeled vehicles, there exists a set of brake shoes namely a leading shoe and a trailing shoe. Such shoes are actuated by rotation of a brake cam to open out the brake shoes. Consequently, the brake shoe is then normally pressed against the rotating brake drum either to slow down or to stop the wheel, ultimately resulting in retardation of the movement of the vehicle. Herein, for each brake application, both brake shoe-liner and brake drum gets substantial wear-out, which is though with infinitesimal amount but the cumulative effect of these wear-out, results in increase in the clearance between the brake drum and brake shoe-liner. After some period of usage or increased number of brake applications, the brake shoe liner as well as the brake-drum-bore significantly wears out. As a consequence, the radial clearance between the brake shoe liner and brake drum bore increases more from the pre-setting value, which was initially provided to meet the ergonomic qualities on brake pedal usage. This increase in clearance also increases the free-play of the brake control lever or brake pedal.
[00021] The changing of the brake shoes is the most common service required for drum brakes. As the shoe wears, the brake pedal travel increases due to an increased shoe-drum clearance. The increased shoe drum clearance is adjusted regularly by tightening an adjuster nut that takes up the increased slack and reduces the shoe-drum clearance which has to be done on a regular basis. However, the failure to adjust the nut can lead to excessive pedal or lever travel and in turn, result in poor brake force application or none at all, under extreme shoe wear. This can be fatal as well.
[00022] Further, to maintain the ergonomic qualities of the brake actuation with the same value (i.e., to control brake lever free-play as against the predetermined as well as the pre-set value), it requires periodical wear adjustment of the braking system.
[00023] As a known prior art, this is usually carried out by the manual adjustment of brake cam lever position with respect to the brake rod or brake cable. After specific number of adjustments, the brake cam lever is reoriented over the brake cam using serration-fit therebetween. In another known prior art, outer brake cable is provided with manual length adjuster in any known way for adjusting the same free-play. The problems in this known prior art is that it requires the manual effort for periodical checking and adjustments either by a user or a skilled mechanic.
[00024] Moreover, such afore-mentioned brake systems which have higher mechanical force amplification from brake control lever to the brake cam functional contact point with the brake shoes, the frequency of this adjustment is very high and thereby more significant. In such known prior arts, the angle between the brake cam lever and the brake cable rod is changed due to the consequence of these adjustments. This results in change of its effective mechanical advantage of brake cam lever.
[00025] In yet another prior art, this manual wear adjustment is called slack adjuster which is also periodically manually used with high adjustment frequency. Another improvement of the former is called the automatic slack adjuster. Herein, such automatic slack adjuster consists of an actuation sensor like an actuation counter and a slack adjuster, which is constituted by a rachet and pawl mechanism. In this, by sensing each brake actuation, the sensor operates the ratchet and pawl mechanism to slack the return movement of the brake control lever with an amount, which is predetermined from the actual wear of each full brake application. But in normal usage, the actual wear-out of brake liner and drum at each brake application will vary from each other due to the inconsistencies in vehicle pay load, initial vehicle speed, road conditions inclusive of gradient and the nature of brake applications i.e., partial, normal or full/panic braking during each brake application.
[00026] Consequently, the amount of predetermined slack adjustment, may not be always equivalent to the actual wear, which causes an error in the actual amount of slack adjusted from the required value. This cumulative error adds up after continuous number of brake applications and gradually changes (particularly reduces) brake pedal free play as against its preset-value and results in affecting the wheel freeness which may ultimately resulting ceasing the brake or the poor ergonomic qualities of brake control levers by increasing its free-play. Hence, this limits the number of brake applications which is a demerit of the known art. However, such automatic slack adjustment mechanisms requires more number of parts, resulting in huge size, highly complicated design and functions, increased weight and initial cost and maintenance costs.
[00027] Certain adjusters attempt to sense the clearance between the brake lining and brake drum during brake application but these depend upon friction clutches and do not operate uniformly from cycle to cycle. Other adjusters attempt to sense the stroke length required for full brake application but accurate adjustment is not achieved because of backlash due to dimensional tolerances and because adjustment is made in finite increments. Certain slack adjusters are difficult to install due to their size and the space required. Other automatic adjusters have external operating parts such as cams and ratchets which may be impaired in operation by road dirt and other elements. Also, some of the prior art slack adjusters fail to facilitate manual adjustment of the camshaft upon initial installation in the vehicle and subsequent periodic maintenance.
[00028] Thus, there arises a need for an effective automatic free-play adjuster mechanism to avoid manual periodic adjustment of the brake system over prolonged usage and which is simpler, less in weight and cost-effective.
[00029] The present subject matter along with all the accompanying embodiments and their other advantages would be described in greater detail in conjunction with the figures in the following paragraphs.
[00030] A general object of this invention is to provide an improved automatic slack adjuster for vehicle brakes which overcomes certain disadvantages of the prior art.
[00031] The present subject matter provides a brake assembly with a free play adjuster device which senses stroke length and produces an adjustment which is infinitely variable and unaffected by backlash due to dimensional tolerances. The free play adjuster of this invention is easy to install and facilitates manual adjustment upon initial installation and during subsequent periodic maintenance. Further, it is of small size and rugged construction with protection of the operating parts against the environment.
[00032] In an embodiment, the present subject matter discloses a brake assembly for a vehicle. Such brake assembly includes a brake cam lever, a brake drum liner, a brake liner where the brake liner is attached to a brake shoe, a forward actuating member, a return actuating member and a frame. Herein, the forward actuating member and the return actuating member is engaged with one or more surfaces of said brake shoe. Further, the frame includes an elastic device. The elastic device has a first end and a second end, the first end is rigidly attached to the frame and the second end is connected to the brake shoe. During normal brake applying stroke of the brake cam lever, the forward actuating member actuates the elastic device to normally expand in a forward direction for engaging the brake liner with the brake drum liner. During over pressing of the brake cam lever resulting from brake application, the forward actuating member actuates the elastic device to fully expand in a forward direction for pushing the brake liner completely to compress the brake drum liner and while during release of the brake cam lever resulting from release of brake application, the return actuating member actuates the elastic device to contract in a backward direction for disengaging the brake liner with the brake drum liner, thereby automatically adjusting free play in the brake assembly during a brake apply stroke and a brake release stroke.
[00033] In another embodiment, the brake cam lever includes one or more first set of racks being integrated at one or more ends of the brake cam lever.
[00034] In yet another embodiment, the frame includes one or more pinion gears being disposed at one or more ends of the frame. Such one or more pinion gears are rotatably engaged with one or more first set of racks.
[00035] In another embodiment, the brake cam lever is split into a first set of rack and a second set of rack.
[00036] In another embodiment, the brake shoe includes a third set of racks being formed at one or more surfaces of said brake shoe.
[00037] In one more embodiment, the forward actuating member comprises a forward clutch, said forward clutch being coupled to one or more first set of racks and one or more pinion gears, said forward actuating member being configured to achieve forward actuation of said elastic device.
[00038] In yet another embodiment, the return actuating member comprises a return clutch, said return clutch being coupled to said one or more first set of racks and said one or more pinion gears, said return actuating member being configured to achieve return actuation of said elastic device.
[00039] In one more embodiment, the one or more pinion gears being rotatably engaged with a second set of racks of the brake cam lever.
[00040] In yet another embodiment, the second set of racks being configured to have a plurality of teeth till a predetermined position and a no-teeth portion.
[00041] In one more embodiment, the one or more pinion gear includes a first pinion gear and a second pinion gear, wherein said first pinion gear being connected to said second pinion gear.
[00042] In yet another embodiment, a method for automatically adjusting free play of a brake assembly of a vehicle is disclosed. Firstly, while applying normal brake stroke using a brake cam lever, by a user, a forward actuating member actuates an elastic device to normally expand in a forward direction for engaging a brake liner with a brake drum liner. During over pressing of said brake cam lever, by the user, said forward actuating member actuates said elastic device to fully expand in a forward direction for pushing said brake liner completely to compress said brake drum liner; and releasing of said brake cam lever, by the user, a return actuating member actuates said elastic device to contract in a backward direction for disengaging said brake liner with said brake drum liner, thereby automatically adjusting free play in said brake assembly during a brake apply stroke and a brake release stroke.
[00043] In another embodiment, wherein during applying normal brake, said brake assembly being in a free play zone, said free play zone being when said brake liner being in touch with said brake drum liner.
[00044] In yet another embodiment, wherein during pressing of said brake cam lever, said brake assembly being in an elasticity zone, said elasticity zone being when said brake liner compressing said brake drum liner.
[00045] In another embodiment, wherein during over pressing of said brake cam lever, said brake assembly being in a wear and plasticity zone, said wear and plasticity zone being when said brake liner over compressing said brake drum liner.
[00046] In yet another embodiment, wherein one or more pinion gears being rotatably engaged with one or more first set of racks and said one or more pinion gears being rotatably engaged with one or more second set of racks and one or more third set of racks.
[00047] In another embodiment, wherein said forward actuating member comprises a forward clutch, said forward clutch being coupled to said one or more first set of racks and said one or more pinion gears, said forward actuating member being configured to achieve forward actuation of said elastic device.
[00048] In another embodiment, wherein said return actuating member comprises a return clutch, said return clutch being coupled to said one or more first set of racks and said one or more pinion gears, said return actuating member being configured to achieve return actuation of said elastic device.
[00049] In yet another embodiment, wherein said second set of rack being configured to have a plurality of teeth till a predetermined position and a no-teeth portion, whereby said one or more pinion gears travel from said plurality of teeth towards no-teeth portion during brake pressing and retracts to initial position travelling from no-teeth portion to said plurality of teeth.
[00050] The present subject matter is further described with reference to accompanying figures. It should be noted that the description and figures merely illustrate principles of the present subject matter. Various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof.
[00051] The brake assembly may be implemented in any two-wheeled vehicle or a three-wheeled vehicle or a four-wheeled vehicle. However, for the purpose of explanation and by no limitation, the brake assembly, and corresponding additional advantages and features are described through the following embodiments. Arrows wherever provided on top right corner of the figure represent direction with respect to vehicle. Arrow F represents forward direction, arrow R represents rearward direction, arrow UW represents upward direction and arrow DW represents downward direction.
[00052] The aforesaid and other advantages of the present subject matter would be described in greater detail in conjunction with the figures in the following description.
[00053] Fig. 1 illustrates a left side view of a two-wheeled vehicle, in accordance with an embodiment of the present subject matter. The vehicle 100 comprises a frame assembly 105 extending from a front portion towards a rear portion of the vehicle 100. A power unit 110 is mounted on the frame assembly 105 of the vehicle 100. The power unit 110 includes at least one of an internal combustion engine or a traction motor. In an embodiment, the power unit 110 is a four-stroke single cylinder type. The power unit 110 includes a starter system. Particularly, the starter system includes an electric start system or a mechanical kick-start system or both that are employed with power unit 110 provided with the IC engine. Through a transmission system 115, a rear wheel 120 is functionally coupled to the power unit 110. The transmission system 115 may include a fixed gear chain drive or continuously variable transmission (CVT) or an automatic manual transmission (AMT) or a multi-speed manual control gearbox system. A rear fender 125 covers at least a portion of the rear wheel 120. Further, one or more rear suspension spring and damper system(s) 130 functionally connect the rear wheel 120 to the frame assembly 105.
[00054] A head tube (not shown) of the frame assembly 105 is rotatably supported by a steering shaft (not shown). A handlebar assembly 135 is connected to the steering shaft. One or more front suspension spring and damper system(s) 140 rotatably support a front wheel 145 and connect the front wheel 145 to the steering shaft. A front fender 150 covers at least a portion of the front wheel 145. A seat assembly 155 is supported by a portion of the frame assembly 105. The fuel tank 160 is disposed in anterior portion of the seat assembly 155 and upwardly of the power unit 110.
[00055] The vehicle 100 comprises a front drum brake assembly 200 disposed at the front wheel 145 and an actuating lever 170 is provided on the handlebar assembly 135. The rear wheel 120 is provided with another drum brake assembly (not shown) that is actuated by a hand-operated lever or a leg operated lever. The vehicle 100 includes a transmission cover 165 covering at least a portion of the transmission 115. Plurality of panels 175A and 175B are disposed longitudinally and downwardly from the seat assembly 155. The internal combustion engine of the power unit 110 will be supplied with air fuel mixture supplied by a fuel tank (not shown) and an air induction system (not shown) that are coupled through a carburetor or a fuel injection system (not shown). The vehicle 100 comprises an auxiliary power source (not shown) that includes a battery or a hydrogen cell or a fuel cell or the like. Further, the traction motor of the power unit 110 is powered by the auxiliary power source mounted on the vehicle 100.
[00056] Further, the vehicle 100 includes various electronic, electrical, and mechanical systems such as a vehicle control unit, an anti-lock braking system, or a synchronous braking system. Also, an electrical starter system, a headlamp 180, and a tail lamp 185 are provided on said vehicle.
[00057] Fig. 2 (a) illustrates a perspective view of the drum brake assembly 200. The drum brake assembly 200 comprises of anchor plate member 205 that supports plurality of brake shoes 210A, 210B. The brake shoes 210A, 210B are arc shaped and each of said shoes 210A, 210B are provided with a frictional liner 210AA, 210BA. One end of the brake shoes 210 are mounted on a pin 215 that is rigidly connected to the anchor member 205. On the other end, a cam member 220 is rotatably supported by the anchor plate member 205 and rigidly connected to a lever 225 in order to secure angular movement therebetween. Further, a brake drum is encasted or affixed to a hub portion (not shown) of the wheel to secure angular movement between them. Therefore, the anchor plate member 205 is a stationary part, while the brake drum rotates along with the wheel.
[00058] The brake drum comprises a circumferential wall that is capable of enclosing the plurality shoes 210A, 210B in circumferential direction. The brake shoes 210A, 210B are connected to each other through plurality of springs 226 that enable restoration to normal state. In normal state of the brake shoes 210A, 210B, free ends of the arc shaped shoes 210 are in contact with a flat surface of the cam member 220. The springs 226 hold the brake shoes 210A, 210B in the normal state. Actuation of brake will enable rotation of the lever 225 that will rotate the cam member 220, which will push the brake shoes 210A, 210B apart from each other thereby moving the brake shoes 210A, 210B towards the inner circumferential surface of the brake drum. Further, the frictional liners 210AA, 210BA provided on the brake shoes 210A, 210B come in contact with the inner circumferential surface of the brake drum. This creates a friction between the frictional liners 210AA, 210BA and brake drum, resulting in reducing the speed of the rotation of the wheel. When the brake actuation lever is released, the springs 226 will retract the brake shoes 210A, 210B to the normal condition.
[00059] Fig. 3 illustrates position of brake liner and brake drum liner at normal brake position when the brake is inoperative. A brake assembly (200) for a vehicle (100) is disclosed wherein said brake assembly (200) comprises: a brake cam lever (225), a brake drum liner (310), a brake liner (210AA), said brake liner (210AA) being attached to a brake shoe (210); a forward actuating member (320), a return actuating member (330), and a frame (105), wherein said forward actuating member (320) and said return actuating member (330) being engaged with one or more surfaces of said brake shoe (210); wherein said frame (105) includes an elastic device (340), said elastic device (340) having a first end and a second end, said first end being rigidly attached to said frame (105) and said second end being connected to said brake shoe (210); wherein during normal brake applying stroke of said brake cam lever (225), said forward actuating member (320) actuates said elastic device (340) to normally expand in a forward direction for engaging said brake liner (210AA) with said brake drum liner (310); wherein during over pressing of said brake cam lever (225) resulting from brake application, said forward actuating member (320) actuates said elastic device (340) to fully expand in a forward direction for pushing said brake liner (210AA) completely to compress said brake drum liner (310); and wherein during release of said brake cam lever (225) resulting from release of brake application, said return actuating member (330) actuates said elastic device (340) to contract in a backward direction for disengaging said brake liner (210AA) with said brake drum liner (310), thereby automatically adjusting free play in said brake assembly (200) during a brake apply stroke and a brake release stroke.
[00060] Fig. 4, Fig. 5, and Fig. 6 are explained here together for brevity purposes. Fig. 4 illustrates position of brake liner touching the brake drum liner when the brake is pressed normally by a user. Fig. 5 illustrates position of brake liner touching the brake drum liner during free play. Fig.6 illustrates position of brake liner compressing the brake drum liner when the brake is over pressed by the user. A method for automatically adjusting free play of a brake assembly (200) of a vehicle (100) is disclosed in the figures. Firstly, applying normal brake stroke using a brake cam lever (225), by a user, a forward actuating member (320) actuates an elastic device (340) to normally expand in a forward direction for engaging a brake liner (201AA) with a brake drum liner (310); during over pressing of said brake cam lever (225), by the user, said forward actuating member (320) actuates said elastic device (340) to fully expand in a forward direction for pushing said brake liner (201AA) completely to compress said brake drum liner (310).
[00061] Fig. 9, 10 and 11 are explained together for brevity purposes. Fig. 9 illustrates position of one or more pinion gear with the one or more racks at the start of free play. Fig. 10 illustrates position of one or more pinion gear with one or more racks during over pressing of brake. Fig. 11 illustrates position of one or more pinion gears with one or more racks during release of brake. The brake cam lever (225) includes one or more first set of racks (225a), said one or more first set of racks (225a) being integrated at one or more ends of said brake cam lever (225). Further, the frame (105) includes one or more pinion gears (901a, 901b), said one or more pinion gears (901a, 901b) being disposed at one or more ends of said frame (105), and said one or more pinion gears (901a, 901b) being rotatably engaged with one or more first set of racks (225a). Further, the brake cam lever (225) is split into a first set of rack (225a) and a second set of rack (225b). Moreover, the brake shoe (210) includes a third set of racks (225c), said third set of racks (225c) being formed at one or more surfaces of said brake shoe. Also, the forward actuating member (320) comprises a forward clutch, said forward clutch being coupled to one or more first set of racks (225a) and one or more pinion gears (901a, 901b), said forward actuating member (320) being configured to achieve forward actuation of said elastic device (340). The return actuating member (330) comprises a return clutch, said return clutch being coupled to said one or more first set of racks (225a) and said one or more pinion gears (901a, 901b), said return actuating member (330) being configured to achieve return actuation of said elastic device (340). The one or more pinion gears (901b) being rotatably engaged with a second set of racks (225b) of said brake cam lever (225). The second set of racks (225b) being configured to have a plurality of teeth (905) till a predetermined position and a no-teeth portion (910). Further, one or more pinion gear includes a first pinion gear (901a) and a second pinion gear (901b), wherein said first pinion gear (901a) being connected to said second pinion gear (901b).
[00062] The figures further disclose a method for automatically adjusting free play of a brake assembly (200), wherein one or more pinion gears (901a) being rotatably engaged with one or more first set of racks (225a) and said one or more pinion gears (901b) being rotatably engaged with one or more second set of racks (225b) and one or more third set of racks (225c). Herein , the forward actuating member (320) comprises a forward clutch, said forward clutch being coupled to said one or more first set of racks (225a) and said one or more pinion gears (901a), said forward actuating member (320) being configured to achieve forward actuation of said elastic device (340). Further, the return actuating member (330) comprises a return clutch, said return clutch being coupled to said one or more first set of racks (225b) and said one or more pinion gears (901b), said return actuating member (330) being configured to achieve return actuation of said elastic device (340). The third set of rack (225c) being configured to have a plurality of teeth (905) till a predetermined position and a no-teeth portion (910), whereby said one or more pinion gears (901b) travel from said plurality of teeth (905) towards no-teeth portion (910) during brake pressing and retracts to initial position travelling from no-teeth portion (910) to said plurality of teeth (905).
[00063] The present subject matter substantially enables to maintain the free-play of brake cam lever by eliminating the effect of the cumulative wear-out of both brake liner and brake drum liner. As the effect of the above-described operations, the free play of brake cam lever is maintained the same as in the beginning, resulting in the elimination of any manual adjustment of free-play or wear-out till the dismantling of above-described brake assembly or reaching the wear-limit whichever is earlier. The present subject matter provides a brake assembly with a free play adjuster device which senses stroke length and produces an adjustment which is infinitely variable and unaffected by backlash due to dimensional tolerances. The free play adjuster of this invention is easy to install and facilitates manual adjustment upon initial installation and during subsequent periodic maintenance. Further, it is of small size and rugged construction with protection of the operating parts against the environment. Thus, the present subject matter provides an effective automatic free-play adjuster mechanism to avoid manual periodic adjustment of the brake system over prolonged usage and which is simpler, less in weight and cost-effective.
[00064] While certain features of the claimed subject matter have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes that fall within the true spirit of the claimed subject matter.


List of reference signs:
100 vehicle
105 frame assembly
110 power unit
115 transmission system
120 rear wheel
125 rear fender
130 rear suspension
135 handlebar assembly
140 front suspension
145 front wheel
150 front fender
155 seat assembly
165 transmission cover
170 actuating lever
175A, 175B panels
180 head lamp
185 tail lamp
200 brake assembly
205 anchor plate
210A, 201B brake shoes
210AA, 210BA brake liners
215 pin
220 cam member
225 brake cam lever
225a first set of racks
225b second set of racks
225c third set of racks
226 springs
310 brake drum liner
320 forward actuating member
330 return actuating member
340 elastic device
901a first pinion gear
901b second pinion gear
905 plurality of teeth
910 no-teeth portion
, C , Claims:We claim:
1. A brake assembly (200) for a vehicle (100), said brake assembly (200) comprises:
a brake cam lever (225),
a brake drum liner (310),
a brake liner (210AA), said brake liner (210AA) being attached to a brake shoe (210);
a forward actuating member (320),
a return actuating member (330), and
a frame (105),
wherein said forward actuating member (320) and said return actuating member (330) being engaged with one or more surfaces of said brake shoe (210);
wherein said frame (105) includes an elastic device (340), said elastic device (340) having a first end and a second end, said first end being rigidly attached to said frame (105) and said second end being connected to said brake shoe (210);
wherein during normal brake applying stroke of said brake cam lever (225), said forward actuating member (320) actuates said elastic device (340) to normally expand in a forward direction for engaging said brake liner (210AA) with said brake drum liner (310);
wherein during over pressing of said brake cam lever (225) resulting from brake application, said forward actuating member (320) actuates said elastic device (340) to fully expand in a forward direction for pushing said brake liner (210AA) completely to compress said brake drum liner (310); and
wherein during release of said brake cam lever (225) resulting from release of brake application, said return actuating member (330) actuates said elastic device (340) to contract in a backward direction for disengaging said brake liner (210AA) with said brake drum liner (310), thereby automatically adjusting free play in said brake assembly (200) during a brake apply stroke and a brake release stroke.

2. The brake assembly (200) as claimed in claim 1, wherein said brake cam lever (225) includes one or more first set of racks (225a), said one or more first set of racks (225a) being integrated at one or more ends of said brake cam lever (225).
3. The brake assembly (200) as claimed in claim 1, wherein said frame (105) includes one or more pinion gears (901a, 901b), said one or more pinion gears (901a, 901b) being disposed at one or more ends of said frame (105), and said one or more pinion gears (901a, 901b) being rotatably engaged with one or more first set of racks (225a).
4. The brake assembly (200) as claimed in claim 1, wherein said brake cam lever (225) being split into a first set of rack (225a) and a second set of rack (225b).
5. The brake assembly (200) as claimed in claim 1, wherein said brake shoe (210) includes a third set of racks (225c), said third set of racks (225c) being formed at one or more surfaces of said brake shoe.
6. The brake assembly (200) as claimed in claim 1, wherein said forward actuating member (320) comprises a forward clutch, said forward clutch being coupled to one or more first set of racks (225a) and one or more pinion gears (901a, 901b), said forward actuating member (320) being configured to achieve forward actuation of said elastic device (340).
7. The brake assembly (200) as claimed in claim 1, wherein said return actuating member (330) comprises a return clutch, said return clutch being coupled to said one or more first set of racks (225a) and said one or more pinion gears (901a, 901b), said return actuating member (330) being configured to achieve return actuation of said elastic device (340).
8. The brake assembly (200) as claimed in claim 3, wherein said one or more pinion gears (901b) being rotatably engaged with a second set of racks (225b) of said brake cam lever (225).
9. The brake assembly (200) as claimed in claim 5, wherein said second set of racks (225b) being configured to have a plurality of teeth (905) till a predetermined position and a no-teeth portion (910).
10. The brake assembly (200) as claimed in claim 8, wherein one or more pinion gear includes a first pinion gear (901a) and a second pinion gear (901b), wherein said first pinion gear (901a) being connected to said second pinion gear (901b).
11. A method for automatically adjusting free play of a brake assembly (200) of a vehicle (100), said method comprising the steps of:

applying normal brake stroke using a brake cam lever (225), by a user, a forward actuating member (320) actuates an elastic device (340) to normally expand in a forward direction for engaging a brake liner (201AA) with a brake drum liner (310);
over pressing of said brake cam lever (225), by the user, said forward actuating member (320) actuates said elastic device (340) to fully expand in a forward direction for pushing said brake liner (201AA) completely to compress said brake drum liner (310); and
releasing of said brake cam lever (225), by the user, a return actuating member (330) actuates said elastic device (340) to contract in a backward direction for disengaging said brake liner (210AA) with said brake drum liner (310), thereby automatically adjusting free play in said brake assembly (200) during a brake apply stroke and a brake release stroke.
12. The method for automatically adjusting free play of a brake assembly (200) as claimed in claim 11, wherein during applying normal brake, said brake assembly (200) being in a free play zone, said free play zone being when said brake liner (210AA) being in touch with said brake drum liner (310).
13. The method for automatically adjusting free play of a brake assembly (200) as claimed in claim 11, wherein during pressing of said brake cam lever (225), said brake assembly (225) being in an elasticity zone, said elasticity zone being when said brake liner (210AA) compressing said brake drum liner (310).
14. The method for automatically adjusting free play of a brake assembly (200) as claimed in claim 11, wherein during over pressing of said brake cam lever (225), said brake assembly (200) being in a wear and plasticity zone, said wear and plasticity zone being when said brake liner (210AA) over compressing said brake drum liner (310).
15. The method for automatically adjusting free play of a brake assembly (200) as claimed in claim 11, wherein one or more pinion gears (901a) being rotatably engaged with one or more first set of racks (225a) and said one or more pinion gears (901b) being rotatably engaged with one or more second set of racks (225b) and one or more third set of racks (225c).
16. The method for automatically adjusting free play of a brake assembly (200) as claimed in claim 11, wherein said forward actuating member (320) comprises a forward clutch, said forward clutch being coupled to said one or more first set of racks (225a) and said one or more pinion gears (901a), said forward actuating member (320) being configured to achieve forward actuation of said elastic device (340).
17. The method for automatically adjusting free play of a brake assembly (200) as claimed in claim 11, wherein said return actuating member (330) comprises a return clutch, said return clutch being coupled to said one or more first set of racks (225b) and said one or more pinion gears (901b), said return actuating member (330) being configured to achieve return actuation of said elastic device (340).
18. The method for automatically adjusting free play of a brake assembly (200) as claimed in claim 16, wherein said third set of rack (225c) being configured to have a plurality of teeth (905) till a predetermined position and a no-teeth portion (910), whereby said one or more pinion gears (901b) travel from said plurality of teeth (905) towards no-teeth portion (910) during brake pressing and retracts to initial position travelling from no-teeth portion (910) to said plurality of teeth (905).