DESC:FIELD OF INVENTION

[0001] The present invention relates to vehicle brakes to ensure the vehicle stoppage distance almost constant. In particular, the present invention relates to a self-adjusting vehicle brake for automatic adjustment of the increased gap created between the brake pedal free-play and worn-out friction plates thereof. More particularly, the present invention relates to a vehicle brake equipped with a hydraulic mechanism connected to an actuating linkage for facilitating an automatic brake setting.

BACKGROUND OF THE INVENTION

[0002] In normal manual brake setting arrangement, once the friction plates of brakes wear-out, the brake pedal is required to travel more, which causes a free play while applying brakes. This increases the overall stoppage distance of the vehicle.

[0003] Therefore, an exact brake setting is required to be manually ensured each and every time to overcome any such free-play while applying brakes.

[0004] This is achieved with the help of a self-adjusting automotive brake system configured in accordance with the present invention, which automatically adjusts the increased gap created between the brake pedal free-play and worn-out friction plates.

OBJECTS OF THE INVENTION

[0005] Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

[0006] An object of the present invention is to provide a cost-effective solution to automatically adjust the gap created between the brake pedal and worn-out friction plates of the vehicle brake.

[0007] Another object of the present invention is to provide an arrangement for simple automatic adjustment of the gap created between the brake pedal and worn-out friction plates of the vehicle brake.

[0008] Still another object of the present invention is to provide a self-adjusting vehicle brake to automatically adjust the brake setting for reducing the gap created between brake pedal and worn-out friction plates of the vehicle brake.

[0009] Yet another object of the present invention is to provide a self-adjusting vehicle brake to automatically adjust the brake setting which facilitates in keeping the vehicle stoppage distance almost constant.

[0010] These and other objects and advantages of the present invention will become more apparent from the following description, when read with the accompanying figures of drawing, which are however not intended to limit the scope of the present invention in any way.

SUMMARY OF INVENTION

[0011] In accordance with an embodiment of the present invention, there is provided an improved self-adjusting vehicle brake system with a brake linkage actuating arrangement having a hydraulic mechanism, wherein the hydraulic mechanism automatically adjusts the gap created between the brake disc and brake drum due to worn-out friction plates for compensating the free play of the brake pedal caused due to the gap, to facilitate in stopping the vehicle at substantially the same distance after applying brakes thereof.

[0012] Typically, the brake system comprises:

- a brake pedal arm having a substantially straight portion and a curved portion;

- a foot pedal fitted at the upper end of the curved portion;

- a foot pedal stopper fitted adjacent the lower end of the curved portion of the brake pedal arm for restricting the upward movement of the brake pedal arm on releasing the brake pedal;

- an extension projecting away from the lower end of the straight portion of the brake pedal arm to form a clevis end thereon;

- a L-plate having the short arm and long arm thereof pivotable about a pivot pin disposed between the short arm and the long arm;

- a spring-loaded brake pull-rod connected to the vehicle brake drum via the short arm-end of the L-plate; and

- a brake actuating linkage connected between the pivot pin and the hydraulic mechanism;

wherein the hydraulic mechanism comprises a lever for actuating the brake actuating linkage and disposed at the upper end thereof, the hydraulic mechanism fitted between the long arm end of the L-plate and the clevis extension end and the brake actuating linkage is fitted between the L-plate pivot pin and the hydraulic mechanism.

[0013] Typically, the hydraulic mechanism further comprises:

a hydraulic oil cylinder connected between the brake pedal extension and the long-arm end of the L-plate; the initial oil pressure inside the hydraulic cylinder being at atmospheric pressure;

- a vacuum chamber disposed parallel to the hydraulic oil cylinder and in fluidic connection thereto;

- a first non-return valve disposed between the upper ends of the hydraulic oil cylinder and the vacuum chamber;

- a second non-return valve disposed between the lower ends of the hydraulic oil cylinder and the vacuum chamber;

- the lever pivotable about a pivot provided at the upper end of the hydraulic mechanism, the lever having a long arm connected to the lower end of the actuating linkage and a short arm configured to actuate the first non-return valve;

wherein the first non-return valve fluidically connects the hydraulic oil cylinder to the vacuum chamber to facilitate oil-flow towards the vacuum chamber and to block the return oil-flow therefrom, and the second non-return valve fluidically connects vacuum chamber to the hydraulic oil cylinder to facilitate oil-flow towards the hydraulic oil cylinder and to block the return oil-flow therefrom for keeping the brake pedal travel constant despite the friction plates wear exceeding a predefined initial limit thereof.

[0014] Typically, the upper end of the actuating linkage comprises an elongated eye having a predefined length corresponding to the predefined initial limit of friction plate wear and the other end of the actuating linkage is connected to the lever at the upper end of the hydraulic mechanism.

[0015] Typically, the lever pivots about the pivot thereof by pressing the brake pedal, whereby the actuating linkage pushes down the lever to open the first non-return valve and the hydraulic cylinder moves downwards to thereby move the piston thereof upwards.

[0016] Typically, the opened first non-return valve facilitates oil-flow from the hydraulic cylinder to the vacuum chamber which thereby opens the second non-return valve to facilitate oil-flow under the piston of the hydraulic cylinder, until the pressure in the hydraulic cylinder and the vacuum chamber equalize at a pressure lower than the initial atmospheric pressure inside the hydraulic cylinder.

[0017] Typically, by releasing the brake pedal, the hydraulic cylinder is pulled up and the actuating linkage is pushed down to close the first non-return valve again and to seal the oil inside the vacuum chamber by closing the second non-return valve, whereby the oil present under the piston maintains the brake pedal travel constant for obtaining the same braking action with friction plates worn-out beyond the predefined limit.
[0018] In accordance with another embodiment of the present invention, there is provided a brake system comprising:

(a) a brake-pedal assembly including:
- a brake pedal arm having a curved upper portion and a straight lower potion;
- a foot pedal connected to the upper portion end of the brake pedal arm;
- an extension for clevis projecting away from the lower portion end of the brake pedal arm; and
- a brake pedal stopper provided adjacent the upper and lower joint of the brake pedal arm;
(b) a hydraulic mechanism connected between the brake actuating linkage arrangement and the brake-pedal assembly; the hydraulic mechanism including:
- a hydraulic oil cylinder connected between the extension for clevis and the long-arm end of the L-plate, the initial pressure inside the hydraulic cylinder at atmospheric pressure;

- a vacuum chamber connected parallel to the hydraulic oil cylinder and in fluid communication therewith via a first non-return valve disposed on the connection line between the upper ends of the hydraulic oil cylinder and the vacuum chamber and via a second non-return valve disposed on the connection line between the lower ends of the hydraulic oil cylinder and the vacuum chamber; and

- a lever for actuating the brake actuating linkage and disposed at the upper end thereof, the lever pivotable about a pivot provided adjacent the upper end of the hydraulic cylinder, the lever having a long arm connected to the lower end of the brake actuating linkage and a short arm to actuate the first non-return valve by pivoting about the pivot thereof; and

(c) a brake actuating linkage connected between the pivot pin and the hydraulic mechanism; the linkage including:
- a first end having elongated eye of a predefined length corresponding to an allowable initial friction plate wear limit before actuation of the hydraulic mechanism; and

- a second end connected to the lever at the upper end of the hydraulic mechanism;

wherein the elongated eye facilitates the extension of the brake actuating linkage to a maximum allowable initial friction plate wear limit, on exceeding the limit, the lever is actuated to open the first non-return valve to facilitate oil-flow from the hydraulic cylinder to the vacuum chamber.

[0019] Typically, the second non-return valve is opened to facilitate oil to flow from the vacuum chamber to the hydraulic cylinder under the piston thereof, until the pressure in the hydraulic cylinder and the vacuum chamber equalize to a pressure lower than the initial atmospheric pressure inside the hydraulic cylinder.

[0020] Typically, the oil under the piston of the hydraulic cylinder permanently reduces the effective length of the hydraulic cylinder to keep the brake pedal distance constant by automatically adjusting the gap between the brake disc and brake drum of the brake system to facilitate in stopping the vehicle at substantially the same distance on applying the brakes with the worn-out friction plates thereof.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0021] The present invention will be briefly described with reference to the accompanying drawings, wherein:

[0022] Figure 1 shows a RH side view of the brake actuating linkage arrangement of the improved vehicle brake configured with a hydraulic mechanism in accordance with the present invention.

[0023] Figure 2 shows an enlarged RH side view of hydraulic mechanism of Fig. 1.

[0024] Figure 3 shows an enlarged LH side view of hydraulic mechanism of Fig. 1.

[0025] Figure 4 shows an enlarged view of the vehicle brake actuating linkage of Fig. 1 in a non-actuated position thereof.

[0026] Figure 5 shows an enlarged view of the vehicle brake actuating linkage of Fig. 1 in an actuated position thereof.

[0027] Figure 6 shows a RH side sectioned view of hydraulic mechanism of Fig.2 in a non-actuated position thereof.

[0028] Figure 7 shows a LH side sectioned view of hydraulic mechanism of Fig. 3 in an actuated position thereof.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0029] In the following, the self-adjusting vehicle brake with a hydraulic mechanism configured in accordance with the present invention will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention in any way.

[0030] Figure 1 shows a RH side view of brake actuating linkage arrangement 100 of the improved vehicle brake system 200 with a hydraulic mechanism 120 configured in accordance with the present invention. It includes a brake pedal arm 102 provided with a foot pedal 104 at one end thereof, a stopper 106 disposed adjacent the curved end of foot pedal 104. This stopper 106 can be restricted in its movement upwards on releasing brake pedal 104 by a stopper provided on vehicle body 210. The other end of brake pedal arm 102 is pivoted at pivot point 108, from which a fixed extension 116 of brake pedal arm 102 forms a clevis thereof which is connected to the first end 112 of a hydraulic mechanism 120. Other end 114 of this hydraulic mechanism 120 is connected to an ‘L’ plate 130 connected to pull rod 140 of brake assembly 200. A brake actuating linkage 150 with one end 152 thereof connected to lever 162 of hydraulic mechanism 120 and the other end thereof provided with an eye 154 connected to pivot 155 of ‘L’ plate 130.

[0031] Figure 2 shows a RH side view of the hydraulic mechanism 120 of Fig. 1. Hydraulic mechanism 120 is provided on brake actuating linkage 150 between ‘L’ plate 130 and clevis extension 116 of brake pedal 102. It includes an oil cylinder 160 connected to the first end 152 of actuating linkage 150 via a lever 162 at pivot pin 164 (Fig. 3) and fitted with a vacuum chamber 166 in parallel to oil cylinder 160. A first non-return valve (NRV) 167 and a second non-return valve (NRV) 168 provide a respective fluidic connection between the upper ends and lower ends of hydraulic cylinder 160 and vacuum chamber 166. First non-return valve 167 can allow oil-flow from hydraulic cylinder 160 to vacuum chamber 166 and the second non-return valve 168 can allow oil-flow from vacuum chamber 166 to hydraulic cylinder 160, as described in the following with respect to Figures 6-7.

[0032] Figure 3 shows a LH side view of the hydraulic mechanism 120 of Fig. 1. Here, the connection of oil cylinder 160 and vacuum chamber 166 as well as the connection of lever 162 via pivot pin 164 to oil cylinder 160 and the connection of lever 162 to actuating linkage 150 is clearly visible. This typical construction of hydraulic mechanism 120 ensures a calculated backward motion of ‘L’ plate 130 and thereby a backward motion of pull rod 140.

[0033] Figure 4 shows an enlarged view of the vehicle brake actuating linkage 150 of Fig. 1 in a non-actuated position thereof. Brake actuating linkage 150 is depicted here in a normal brake condition, in which friction plates are not worn-out considerably. Therefore, actuating linkage 150 remains free of tensile forces therein and merely adjusts this initial gap due to wear of friction plates by downward movement L of said eye 154 provided at the other end of brake actuating linkage 150.

[0034] Figure 5 shows an enlarged view of the vehicle brake actuating linkage 150 in an actuated position thereof. Once the friction plates are considerably worn-out (Fig. 4) and eye 154 has compensated the gap formed in friction plates due to initial wear thereof, the brake actuating linkage 150 starts moving further downwards in direction L by finally getting locked at pivot point 155 of ‘L’ plate 130. The lower end of actuating linkage 150 is connected to lever 162. When brake pedal 102 continues to move downward (in direction L) by applying braking force, hydraulic mechanism 120 also starts moving downwards, thereby tending to rotate lever 162 about pivot pin 164 (in direction R) and actuates to open first non-return valve (NRV) 167.

[0035] Figure 6 shows a RH side sectioned view of the hydraulic mechanism 120 of Fig.2 in a non-actuated position thereof. Oil cylinder 160 contains oil 165 at atmospheric pressure and connects vacuum chamber 166 via first NRV 167. Once NRV 167 is actuated, oil 165 inside hydraulic cylinder 160 starts flowing towards vacuum chamber 160 via this valve 167 due to low pressure (vacuum) in vacuum chamber 166. This oil-flow tendency continues until there is a pressure difference between the hydraulic cylinder 160 and vacuum chamber 166, and finally the equalized pressure inside vacuum chamber 166 and hydraulic cylinder 160 fall below the atmospheric pressure.

[0036] Figure 7 shows a LH side sectioned view of the hydraulic mechanism of Fig.2 in an actuated position thereof. On releasing brake pedal 102 due to the pressure in oil cylinder 160 now being lower than the atmospheric pressure, piston 170 tries to travel in an upward direction U and thus, oil starts flowing under piston 170 through second non-return valve (NRV) 168 to raise the piston up inside hydraulic cylinder 160, while NRV 168 does not allow this oil under piston 170 to return to vacuum chamber 166. This locks the piston in position and prevents it from going back downwards to its original lower position and this helps in removing the free play present in brake pedal 102 travel due to the gap created between the brake disc and brake drum due to friction plates worn-out beyond the initially permissible wear limit. This reduces the effective length of hydraulic cylinder 160. Now, on applying the brake next time, since the free-play in brake pedal travel present earlier was already compensated by the aforesaid reduced hydraulic cylinder length, the brake pedal travel still remains same as earlier, when there is no friction plates/liners wear beyond permissible limit. Because, oil displaced under piston 170 in hydraulic cylinder 160 has reduced this gap to eliminate free-play. This way, the linkage arrangement 150 equipped with hydraulic mechanism 120 used in the improved vehicle brake assembly/system 200 configured in accordance with the present invention continues to prevent excessive brake pedal travel caused due to gap created between the brake disc and brake drum due to friction plate wear by pushing more oil under piston 170 and which does not go back to vacuum chamber 166 through non-return valve 168.

[0037] Accordingly, this improved self-adjusting brake assembly/system 200 with a brake linkage actuating arrangement having a hydraulic mechanism and configured in accordance with the present invention successfully facilitates an automatic adjusts the brake setting by compensating the gap caused due to friction plate wear by reducing the effective length of hydraulic cylinder 160 by incrementally moving piston 170 upward or raising it inside oil cylinder 160 depending on the friction plate getting worn-out beyond initially permissible wear limit, which is adjusted by the eye length before actuating hydraulic mechanism 120. Here, the dimensions of vacuum chamber 166 is defined depending on the maximum allowable wear of friction plates or the maximum allowable gap formed between the brake disc and brake drum.

WORKING OF THE INVENTION

[0038] The self-adjusting vehicle brake system with a brake linkage actuating arrangement having a hydraulic mechanism configured in accordance with the present invention operates in the manner described below:

1) In normal brake condition, in which friction plates of the brake are initially not worn-out considerably, thus the standard stoppage distance of vehicle is not affected on vehicle being stopped by operating the brakes. In this condition, eye 154 is at its uppermost position on pivot pin 155, thereby actuating linkage 150 does not experience any tension therein and hydraulic mechanism 120 remains in a non-actuated condition.

2) Once the friction plates of brakes worn-out beyond a certain limit, on applying brakes, eye 154 starts being pulled down by lever 162 of hydraulic mechanism 120 and eye 154 gets locked on pivot 155.

3) On pressing foot pedal 104 further, hydraulic cylinder 160 also moves down and thereby lever 162 is rotated clockwise about pivot 164 which in turn actuates to open first non-return valve (NRV) 167.

4) Since hydraulic cylinder 160 is initially filled with oil 165 at atmospheric pressure and vacuum chamber 166 has zero pressure, on opening of this first NRV 167, oil starts flowing from cylinder 160 into vacuum chamber until pressure in cylinder 160 and vacuum chamber 166 equalize, thus bringing oil pressure in cylinder 160 below atmospheric pressure.

5) On releasing brake pedal 104, due to oil pressure in cylinder 160 now being lower than atmospheric pressure, piston 170 in cylinder 160 starts travelling upwards and thus second NRV 168 opens and oil present in vacuum chamber 166 starts flowing into cylinder 160, however this NRV 168 blocks any reverse flow of oil present under piston 170 towards vacuum chamber 166, thereby locking piston 170 in this position.

6) However, with this piston’s upward movement, the effective length of the hydraulic mechanism is reduced, and the additional gap created between the brake disc and brake drum due to friction plates worn-out beyond permissible limit is successfully compensated, which leads to the same brake pedal travel required on applying brakes to stop vehicle at the standard distance. (In the absence of this gap compensation, the vehicle would not have stopped at the standard braking distance, which would have been dangerous for vehicle operation and may pose threat of accidents).

7) Now, on releasing the brake pedal, piston 170 remains in its higher position due to oil locked thereunder and the brake pedal travel remains the same as before initially permissible worn-out friction plates.

8) This self-adjustment of vehicle brake system continues until brakes ultimately fail due to excessively worn-out friction plates, and the large disc-drum gap created thereby cannot be compensated even by this hydraulic mechanism 120 and ultimately the friction plates have to be replaced.

9) Accordingly, the vehicle brake system equipped with the hydraulic mechanism of the present invention requires no manual brake setting.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

[0039] The self-adjusting vehicle brake system with a brake linkage actuating arrangement having a hydraulic mechanism configured in in accordance with the present invention has the following technical and economic advantages:

1. No need of manual brake setting.

2. Risk of accident minimizes, improves safety.

3. High accuracy to accommodate the gap between brake disc and brake drum due to worn-out friction plates.

4. Free play in brake pedal travel due to friction plate wear is totally avoided.

[0040] The exemplary embodiment described in this specification are intended merely to provide an understanding of various manners in which this embodiment may be used and to further enable the skilled person in the relevant art to practice this invention. Therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiment.

[0041] It is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation. The descriptions of well-known components and manufacturing and processing techniques are consciously omitted in this specification, so as not to unnecessarily obscure the specification.

[0042] Therefore, while the embodiment herein has been described in terms of a preferred embodiment, the skilled person can easily make innumerable changes, variations, modifications, alterations and/or integrations in terms of materials and method used to configure, manufacture and assemble various constituents, components, subassemblies, assemblies and in terms of the size, shapes, orientations and interrelationships without departing from the scope and spirit of the present invention.

[0043] Many of the fastening, connection, processes and other means and components utilized in this invention are widely known and used in the field of the invention described, and their exact nature or type is not necessary for an understanding and use of the invention by a person skilled in the art and they will not therefore be discussed in significant detail.

[0044] The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure unless there is a statement in the specification to the contrary.

[0045] Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to implies including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps.
[0046] In the claims and the description, the terms “containing” and “having” are used as linguistically neutral terminologies for the corresponding terms “comprising”.

[0047] Also, any reference herein to the terms ‘left’ or ‘right, ‘up’ or ‘down, or ‘top’ or ‘bottom’ are used as a matter of mere convenience and are determined by standing at the rear of the machine facing in its normal direction of travel.

LIST OF REFERENCE NUMERALS

100 Brake actuating linkage arrangement
120 Hydraulic mechanism
130 L-plate
140 Brake pull rod of brake assembly 200
150 Actuating linkage
160 Oil cylinder 160
170 Piston in oil cylinder 160.
200 Improved vehicle brake assembly/system
210 Vehicle body
102 Brake pedal arm 102
104 Foot brake pedal
106 Stopper
108 Pivot point of brake pedal arm 102
112 First end 112 of hydraulic mechanism 120
114 Second end of hydraulic mechanism 120
116 Clevis extension of brake pedal arm 102
152 First end of actuating linkage 150
154 Eye at second end of actuating linkage 150
155 Pivot of L-plate 130
162 Lever of hydraulic mechanism 120
164 Pivot pin
166 Vacuum-chamber
167 First non-return valve (NRV)
168 Second non-return valve (NRV) ,CLAIMS:We claim:

1. An improved self-adjusting vehicle brake system (200) with a brake linkage actuating arrangement (100) having a hydraulic mechanism (120), wherein said hydraulic mechanism automatically adjusts the gap created between the brake disc and brake drum for compensating the free play of brake pedal caused due to said gap to facilitate in stopping vehicle at almost the same distance after applying brakes thereof.

2. Self-adjusting brake system (200) as claimed in claim 1, wherein said brake system comprises:

• a brake pedal arm (102) having a straight portion and a curved portion;

• a foot pedal (104) fitted at the upper end of said curved portion;

• a foot pedal stopper (106) fitted adjacent the lower end of said curved portion of said brake pedal arm for restricting the upward movement of said brake pedal arm on releasing said brake pedal;

• an extension (116) projecting away from the lower end of said straight portion of said brake pedal arm (102) to form a clevis thereon;

• a L-plate (30) having a short arm and a long arm thereof pivotable about a pivot (155) disposed between said short arm and said long arm;

• a spring-loaded brake pull-rod (140) connected to the vehicle brake drum via said short arm-end of said L-plate; and

• a brake actuating linkage (150) connected between said pivot (155) and said hydraulic mechanism (120);

wherein said hydraulic mechanism (120) comprises a lever (162) for actuating said brake actuating linkage (150) and disposed at the upper end thereof, said hydraulic mechanism fitted between said long arm end of said L-plate (130) and said clevis extension (116) end and said brake actuating linkage is fitted between said L-plate pivot (155) and said hydraulic mechanism.
3. Self-adjusting brake system (200) as claimed in claim 2, said hydraulic mechanism (120) further comprises:

• a hydraulic oil cylinder (160) connected between said clevis extension (116) and the long-arm end of said L-plate (130); the initial oil pressure inside said hydraulic cylinder (160) being at atmospheric pressure; a piston (170) moveable within said hydraulic cylinder to displace oil present therein;

• a vacuum chamber (166) disposed parallel to said hydraulic oil cylinder (160) and in fluidic connection thereto;

• a first non-return valve (167) disposed between the upper ends of said hydraulic oil cylinder (160) and said vacuum chamber (166);

• a second non-return valve (168) disposed between the lower ends of said hydraulic oil cylinder (160) and said vacuum chamber (166);

• said lever (162) pivotable about a pivot pin (164) provided at the upper end of said hydraulic mechanism, said lever having a long arm connected to the lower end of said actuating linkage (150) and a short arm configured to actuate said first non-return valve (167);

wherein said first non-return valve (167) fluidically connects said hydraulic oil cylinder (160) to said vacuum chamber (166) to facilitate oil-flow towards said vacuum chamber and to block return oil-flow therefrom, and said second non-return valve (168) fluidically connects vacuum chamber to said hydraulic oil cylinder to facilitate oil-flow towards said hydraulic oil cylinder and to block return oil-flow therefrom for keeping brake pedal (102) travel constant despite friction plates wear exceeding a predefined initial limit thereof.

4. Self-adjusting brake system (200) as claimed in claim 3, wherein the upper end of said actuating linkage (150) comprises an elongated eye (154) having a predefined length corresponding to said predefined initial limit of friction plates wear and the other end of said actuating linkage is connected to said lever (162) at the upper end of said hydraulic mechanism.
5. Self-adjusting brake system (200) as claimed in claim 4, wherein said lever (162) pivots about pivot pin (164) thereof on pressing said brake pedal (102), for said lever to be pushed down by said actuating linkage (150) for opening said first non-return valve (167) and to move said hydraulic cylinder (160) downwards for moving said piston (170) upwards.

6. Self-adjusting brake system (200) as claimed in claim 5, wherein said open first non-return valve (167) facilitates oil-flow from said hydraulic cylinder (160) to said vacuum chamber (166) for opening said second non-return valve (168) to facilitate oil-flow under said piston (170) and said piston is raised within said hydraulic cylinder, until pressure in said hydraulic cylinder and said vacuum chamber equalize.

7. Self-adjusting brake system (200) as claimed in claim 6, wherein by releasing said brake pedal (102), said hydraulic cylinder (160) is pulled up and said actuating linkage (150) is pushed down for closing said first non-return valve (167) again and for sealing the oil inside said vacuum chamber (166) by closing said second non-return valve (168), thereby locking said piston (170) in position keeping the oil present under said piston for maintaining a constant brake pedal travel to obtain the same standard braking action even with friction plates worn-out beyond a predefined limit.

8. Self-adjusting brake system (200) as claimed in claim 1, wherein said brake system comprises:

(a) a brake-pedal assembly including:

• a brake pedal arm (102) having a curved upper portion and a straight lower potion;
• a foot pedal (104) connected to said upper portion end of said brake pedal arm;

• a clevis extension (116) projecting away from said lower portion end of said brake pedal arm; and

• a brake pedal stopper (106) provided adjacent said upper and lower joint of said brake pedal arm;

(b) a hydraulic mechanism (120) connected between said brake actuating linkage arrangement (100) and said brake-pedal assembly; said hydraulic mechanism including:

• a hydraulic oil cylinder (160) connected between said clevis extension (116) and said long-arm end of a L-plate (130), the initial pressure inside said hydraulic cylinder being at atmospheric pressure;

• a vacuum chamber (166) connected parallel to said hydraulic oil cylinder (160) and in fluid communication therewith via a first non-return valve (167) disposed on the connection line between the upper ends of said hydraulic oil cylinder (160) and said vacuum chamber (166) and via a second non-return valve (168) disposed on the connection line between the lower ends of said hydraulic oil cylinder and said vacuum chamber;

• a lever (162) for actuating a brake actuating linkage (150) and disposed at the upper end thereof, said lever pivotable about a pivot pin (164) provided adjacent the upper end of said hydraulic cylinder, said lever having a long arm connected to the lower end of said brake actuating linkage and a short arm to actuate said first non-return valve (167) by pivoting about said pivot pin; and

(c) said brake actuating linkage connected between said pivot pin (164) and said hydraulic mechanism (120); said brake actuating linkage including:

• a first end (152) connected to said lever at the upper end of said hydraulic mechanism; and

• a second end having an elongated eye (154) of a predefined length corresponding to an allowable initial friction plate wear limit before actuation of said hydraulic mechanism (120);

wherein said elongated eye (154) facilitates the extension of said brake actuating linkage (150) to a maximum allowable initial friction plate wear limit, and on exceeding said limit, said lever (162) is actuated to open said first non-return valve (167) to facilitate oil-flow from said hydraulic cylinder (160) to said vacuum chamber (166).

9. Self-adjusting brake system (200) as claimed in claim 8, wherein said second non-return valve (168) is opened to facilitate oil-flow from said vacuum chamber (166) to said hydraulic cylinder (160) and under said piston to raise the same therein, until the pressure in said hydraulic cylinder and said vacuum chamber equalizes.

10. Self-adjusting brake system (200) as claimed in claim 9, wherein said oil (165) present under said piston (170) of said hydraulic cylinder (160) permanently reduces the effective length thereof to keep the brake pedal distance constant by automatically adjusting the gap between brake disc and brake drum of said brake system (200) to facilitate in stopping vehicle at substantially the same distance on applying brakes even with said friction plates worn-out beyond said initially permissible wear limit thereof.

Digitally Signed.
Dated: this 12th day of March 2018. (SANJAY KESHARWANI)
APPLICANT’S PATENT AGENT
IN/PA-2043.