DESC:FORM 2
The Patent Act 1970
(39 of 1970)
&
The Patent Rules, 2005

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

TITLE OF THE INVENTION
“DUAL COMBINED-BRAKING-SYSTEM FOR TWO-WHEELER”

Endurance Technologies Limited
E-92, M.I.D.C. Industrial Area, Waluj,
Aurangabad – 431136, Maharashtra, India

The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed.

Field of Invention

[001] The present invention is related to a combined-braking-system (CBS) for a two-wheeled vehicle. More particularly, the invention is related to a dual valve assembly of combined braking system for two wheeled motor vehicles, preferably bikes and scooters, wherein the dual CBS valve assembly is configured to operate both the brakes, rear and front, on actuation of any of the levers, rear lever and front lever, and also eliminates the reverse movement of the piston of the valve leading to effective combined braking performance.

Background of the Invention

[002] Braking system is an important sub-system of a two wheeled vehicle. The braking systems in two wheelers have varied throughout time, as the two-wheeled vehicles evolved from bicycles with an engine attached. A gradual development has been carried out in two-wheeler industry to provide an improved and efficient braking system. Various kind of braking systems such as mechanical, hydraulic, anti-lock, combined braking system have been gradually developed to cater the safety and efficient braking in two-wheeler industry. In recent decade two-wheeler industry is more focusing to provide an efficient combined braking system and it is being well accepted by the end-user.

[003] A combined braking system (CBS), also called linked braking system (LBS), is a system for linking front and rear brakes on a motorcycle or scooter. In this system, the rider's action of depressing the rear brake lever applies both the brakes, rear followed by the front brake. The amount of brake applied may be determined by a proportional control valve and this control valve is called as CBS Valve which plays a crucial role in implementation and working of the combined braking system on two wheeled vehicles. Since April 2019, Govt. of India has mandated Combined Braking System (CBS) on all new two-wheelers below 125 cc.

[004] The conventional two-wheeler combined braking system with front and rear combination of hydraulic and mechanical brake normally employs use of actuation levers, equalizers, cables, master cylinders, hydraulically operated front wheel brake and mechanically operated rear wheel brake. These features are essentially provided for achieving combined braking function with required time delay in application of front wheel brake when rear wheel brake is applied. The implementation of these systems presuppose existence of sufficient manufacturing and assembly expertise to reliably provide them on any given two wheeler. It also presupposes existence of adequate space on the two-wheeler which may not always be the case.

[005] The combined braking systems available in public domain have been implemented with varying degree of success. Various combined braking systems with mechanical or hydraulic actuation arrangements have been reported in the prior art. The document No. IN202121046218A discloses an integrated master cylinder assembly that addresses the drawbacks of prior art solutions. The master cylinder assembly disclosed accommodates in its vicinity multiple levers, a plurality of mechanical links with complicated profiles to ensure its operability making the system more bulky, complex and cost intensive. Further, in this system having number of mechanical links, consistency in its braking performance is a debatable issue. Thus, the system of referred prior art has a very complicated construction having multiple sub-components that need precise and accurate manufacturing for ensuring reliable combined braking operation.

[006] Further, the combined braking systems of the prior art do not disclose the operation of both the brakes (rear and front) through the hydraulic lines by the controlled dual CBS valve assembly. These systems even do not addresses the issue of reverse movement of the piston of the dual CBS valve assembly leading. Hence, there exists a long pending unmet need of providing a dual combined braking system with a dual CBS valve assembly that is configured to actuate both the brakes on application of any of the brake levers, front and rear and thereby impart safety to the rider and provides compact system efficient braking performance at an economic cost.

Objectives of the Invention

[007] The main object of the present invention is to provide a dual combined-braking-system for a two-wheeler.

[008] The object of the present invention is to provide a dual combined-braking-system for a two-wheeler wherein the dual CBS valve assembly is configured to apply both the brakes, rear and front, on actuation of any of the brake levers, rear and front.

[009] Another object of the present invention is to provide a dual combined-braking-system for a vehicle wherein the dual CBS valve assembly is configured to form a plurality of working chambers.

[0010] Still another object of the present invention is to provide a dual combined-braking-system for a vehicle wherein the dual CBS valve assembly is configured to have a valve body having two parallel cavities bored therein and said cavities are in hydraulic communication with each other through the hydraulic passages; and the valve body is configured to have air vent holes and each of the vent holes opens in each of the working chambers.

[0011] Yet, the object of the present invention is to provide a dual combined-braking-system for a vehicle wherein the dual CBS valve assembly is configured and designed to eliminate the reverse movement of the piston of the valve leading to effective combined braking performance.

[0012] It is yet another objective of the invention to provide a dual combined-braking-system that provides the superior braking performance while maintaining the quality of braking as well as keeping the cost of production low.

[0013] Further, the objective of the invention to provide a dual combined-braking-system that is suitable for any type of two-wheeler viz. motorcycles, scooters, etc.

[0014] Yet, the object of the present invention is to provide a dual combined-braking-system that is compact in structure, cost-effective, has less complexity and is very much user friendly.

Brief Description of the Drawings

[0015] Figure 1a discloses schematic view of a dual combined-braking-system along with the dual CBS valve assembly in accordance with the present invention.

[0016] Figure 1b discloses schematic view of a dual combined-braking-system with the cut sectional view of the dual CBS valve assembly in accordance with the present invention.

[0017] Figure 2 discloses a cut sectional view of the dual CBS Valve body of dual combined-braking-system in accordance with the present invention.

[0018] Figures 3a and 3b disclose an enlarged cut sectional view of piston assemblies of the dual CBS Valve in accordance with the present invention.

[0019] Figure 4 shows enlarged cut sectional view of the dual CBS Valve assembly of dual combined-braking-system of the present invention.

[0020] Figure 5a discloses a cut sectional view of the dual CBS Valve assembly of dual combined-braking-system of the present invention in operating condition when the front brake lever is actuated.

[0021] Figure 5b discloses a cut sectional view of the dual CBS Valve assembly of dual combined-braking-system of the present invention in working condition when the rear brake lever is actuated.
Detailed Description of the Present Invention

[0022] Referring to Figs. 1a and 1b, dual combined-braking-system (500) for a two-wheeler comprises of a rear master cylinder assembly (30) mounted on the left end of the handle bar or on the vehicle body in case of foot operated rear brake lever, front master cylinder assembly (32) mounted on the right end of the handle bar, rear braking unit (34), front braking unit (36), a plurality of hydraulic lines (40a, 40b, 40c, 40d ) and dual CBS valve assembly (100). The dual CBS valve assembly (100) is in hydraulic communication with the front and rear master cylinder assemblies (32 and 30) through the hydraulic lines (40a and 40b) and front and rear brake units (36 and 34) through the hydraulic lines (40c and 40d).

[0023] Referring to Figs. 1b and 4, the dual CBS valve assembly (100) comprises of CBS valve body (1), a plurality of covers (2), a plurality of seal washers (3), a pair of delay springs (4F, 4R), a pair of piston assemblies (PA, PB), a pair of fixed piston (11a, 11b), O-rings (12), a pair of secondary seals (9 and 13) for the rear brake lever operated circuit, a pair of seal guide plates (10 and 14) for the rear brake lever operated circuit and a pair of plate lock springs (15a, 15b). Further, the dual CBS valve assembly (100) has a pair of supply ports (26 and 24) to receive the hydraulic supply from the rear master cylinder (30) and front master cylinder (32), respectively. It also has a pair of outlet ports (20 and 22) for the fluid supply to the front braking unit (36) and the rear braking unit (34), respectively. The piston assembly (PA, PB) of the dual CBS valve (100) comprises of a primary piston (7F, 7R), a secondary piston (5F, 5R), a primary seal (6) for the front brake lever operated circuit, and a primary seal (8) for the rear brake lever operated circuit.
[0024] Referring to Fig. 2, the dual CBS valve body is configured to have two hollow multi-step profiled cavities (C and D) bored therein having their central axes parallel to each other and said cavities (C and D) are in hydraulic communication with each other through the hydraulic passages (27 and 29). The cavity (C) has a plurality of stepped profiles (C1, C2, C3, C4) formed adjacent to each other in an order of decreasing diameter and a plurality of stepped profiles (C5, C6, C7) formed adjacent to each other in an order of increasing diameter, progressing from an end (E1) to an end (E2) of the CBS valve body (1). The cavity (D) has a plurality of stepped profiles (D1, D2, D3, D4) formed adjacent to each other in an order of decreasing diameter and a plurality of stepped profiles (D5, D6, D7) formed adjacent to each other in an order of increasing diameter, progressing from an end (E2) to an end (E1) of the CBS valve body (1).

[0025] Referring to Fig. 4, the stepped profiles (C1 and C7) of the cavity (C) houses a cover (2) at the ends (E1 and E2), respectively and the stepped profiles (D7 and D1) of the cavity (D) houses a cover (2) at the ends (E1 and E2), respectively of the CBS valve body (1). The stepped profile (C3) of the cavity (C) and the stepped profile (D3) of the cavity (D) houses the secondary seal (9). The profile (C6) of the cavity (C) and the profile (D6) of the cavity (D) houses a fixed piston (11).

[0026] The profile (C2) forms a working chamber (W1) and said working chamber (W1) of the cavity (C) houses a secondary piston (5F), a delay spring (4F), a primary seal (6) and a plate lock spring (15a). The said secondary piston (5F) divides the working chamber (W1) into a brake fluid chamber (50a) and a replenishing chamber (80a). The profile (C5) forms a working chamber (W2) and said working chamber houses a primary piston (7F) dividing the said working chamber (W2) into a brake fluid chamber (60a) and a pocket (70a). The profile (C4) of the cavity (C) facilitates the primary piston (7F) to mechanically communicate with the working chamber (W1).

[0027] The profile (D2) forms a working chamber (W3) and said working chamber (W3) of the cavity (D) houses a secondary piston (5R), a delay spring (4R), a primary seal (6) and a plate lock spring (15b). The said secondary piston (5R) divides the working chamber (W3) into a brake fluid chamber (50b) and a replenishing chamber (80b). The profile (C5) forms a working chamber (W4) and said working chamber (W4) houses a primary piston (7R) dividing the said working chamber (W4) into a brake fluid chamber (60b) and a pocket (70b). The profile (D4) of the cavity (D) facilitates the primary piston (7R) to mechanically communicate with the working chamber (W3).

[0028] Further, brake fluid chamber (50a) of the working chamber (W1) in the cavity (C) is in hydraulic communication with the brake fluid chamber (60b) of the working chamber (W4) in the cavity (D) through the hydraulic passage (27). The brake fluid chamber (60a) of the working chamber (W2) in the cavity (C) is in hydraulic communication with the brake fluid chamber (50b) of the working chamber (W3) in the cavity (D) through the hydraulic passage (29).

[0029] The valve body (1) of the dual CBS valve assembly (100) is configured to have a pair of supply ports (26 and 24) and a pair of outlet ports (20 and 22) extending out orthogonally from the outer cylindrical surface of said CBS valve body (1). The each of the supply ports (26 and 24) is projecting out opposite to the respective outlet port (22, 20) and is positioned at offset with each other. The said supply ports (26 and 24) and the outlet ports (20 and 22) are placed diagonally opposite to each other on the valve body (1). Each of the supply ports (26 and 24) is configured to have a replenishing passage (25a, 25b) communicating with the respective replenishing chambers (80a and 80b). The replenishing passage (25) facilitates to avoid the jerk/impact being generated due to sudden braking / application of the front brake. The said replenishing passages (25a, 25b) makes an acute angle (a) with the vertical axis (x-x) of the respective supply port (26, 24) and said angle (a) varies in the range of 30 to 60 degree.

[0030] Referring to Figs. 3a, and 3b the piston assembly (PA and PB) comprises of a primary piston (7F, 7R) and a secondary piston (5F, 5R), respectively. The primary piston (7F, 7R) is configured to have a pair of sliding faces (7P1 and 7P2) projecting out from its peripheral surface and a stepped profiled distal end (7T) to get it fitted in the secondary piston (5F, 5R) respectively. The secondary piston (5F, 5R) is configured to have a hollow cylindrical cavity (5C) bored at its one end to receive the stepped profiled distal end (7T) of the respective primary piston (7F, 7R) and it has a pair of sliding face (5P1 and 5P2) on the outer peripheral surface of the cylindrical cavity (5C) of the secondary piston (5F and 5R).

[0031] The fixed piston (11a, 11b) has a cylindrical groove (11G) bored therein to receive the shank (7s) of the primary piston (7F, 7R) and said fixed piston (11a, 11b) is rigidly fitted inside the respective profiled cavity (C6, D6) and is locked there with the help of an O-ring (12) positioned in a groove provided on the outer peripheral surface of the said fixed piston (11a, 11b). The open end of the cylindrical groove (11G) of fixed piston (11a, 11b) has a stepped profile to accommodate the secondary seal (13) therein and said seal (13) is getting locked there with the seal guide plate (14) fitted against the step portion of the profiles (C6 and C5) and (D6 and D5), respectively. The shank (7s) of the primary piston (7F, 7R) is slideably fitted inside the cylindrical groove (11G) of the respective fixed piston (11a, 11b) in such a way that the sliding faces (7P1 and 7P2) of the primary piston (7F, 7R) are getting positioned in the respective working chambers (W2, W4), respectively. The stepped profiled distal end (7T) of the primary piston (7F, 7R) is getting positioned in the respective working chamber (W1, W3), respectively after passing through the stepped profiles (C3 and C4) for the primary piston (7F) and the stepped profiles (D3 and D4) for the primary piston (7R). The positioning of the primary piston (7F, 7R) forms the first brake fluid chamber (60a, 60b) between the seal guide plate (14) and the sliding face (7P2) of the primary piston (7F, 7R) within the working chamber (W2) for the primary piston (7F) and within the working chamber (W4) for the primary piston (7R). The primary seal (8) is fitted in between the sliding face (7P1) and the sliding face (7P2) of the respective primary piston (7F, 7R) so as to seal the leakage / passage of brake fluid in the pocket (70a, 70b) from the respective brake fluid chamber (60a, 60b).

[0032] The secondary piston (5F, 5R) through its hollow cylindrical cavity (5C) is fitted over the stepped profiled distal end (7T) of the respective primary piston (7F, 7R) and locked there through a suitable joining means. The said joining means is preferably selected from threaded joint, press-fit joint and combination thereof. Thus, the piston assembly (PA, PB) of primary piston (7F, 7R) with the respective secondary piston (5F, 5R) is configured to move axially within the respective working chambers (W1-W2, W3-W4) of the multi-step cylindrical profiled cavity (C, D) of the CBS valve body (1). The positioning of the secondary piston (5F, 5R) forms the replenishing chamber (80a, 80b) and the brake fluid chamber (50a, 50b) within the respective working chamber (W1, W3). The replenishing chamber (80a, 80b) is being formed between the rear side of the sliding face (5P2) of the respective secondary piston (5F, 5R) and the seal guide plate (10) and the brake fluid chamber (50a, 50b) is formed between the primary seal (6) and the seal washer (3) fitted in the respective stepped profile (C2, D2). The primary seal (6) is fitted in between the sliding face (5P1) and the sliding face (5P2) of the secondary piston (5F, 5R) so as to seal the leakage / passage of brake fluid from the brake fluid chamber (50a, 50b) to the respective replenishing chamber (80a, 80b). The secondary seal (9) is fitted in the profiled cavity (C3, D3) and locked there with the help of seal guide plate (10) and said seal guide plate (10) is retained at its position with the plate lock spring (15a, 15b). The delay spring (4F, 4R) is concentrically sleeved over the respective secondary piston (5F, 5R) and in between the sliding face (5P1) and the seal washer (3) fitted at the end (E1 and E2) of the CBS valve body (1). The stepped profiles (C1 and D7) at end (E1) of the CBS valve body (1) and the stepped profiles (D1 and C7) at end (E2) of the CBS valve body (1) are closed with the covers (2) fitted therein. The plate locking spring (15a, 15b) is positioned in the replenishing chamber (80a, 80b) in between the sliding face (5P2) of the secondary piston (5F, 5R) and the seal guide plate (10) to fix the position of the seal guide plate (10) and the secondary seal (9) is fitted in the stepped profile (C5, D5).

[0033] In accordance with the dual CBS valve assembly (100) of the present invention (Fig. 4), the plate lock spring (15) is intelligently placed in the replenishing chamber (80a, 80b) in between the sliding face (5P2) of the secondary piston (5F, 5R) and the seal guide plate (10). This plate lock spring (15) maintains the position of the seal guide plate (10) intact with the face of the stepped profile (C2, D2) thereby restricting the axial movement of the secondary seal (9) from the stepped profile (C3, D3) in response to the axial movement of the respective piston assembly (PA, PB).

[0034] The CBS valve body (1) of the dual CBS valve assembly (100) is provided with a pair of air vent hole (VH) which get opened / communicates with the pocket (70a, 70b). This air vent (VH) facilitate to apply atmospheric pressure on the piston assembly and thereby eliminates the locking / jamming of the piston assembly into the pocket (70a, 70b) during its working when brake lever is released. The rear braking unit (34) of the combined braking system (500) of the present invention is mounted on the rear wheel of the vehicle and is selected from a drum brake and disc brake. The front braking unit (36) of the present invention is mounted on the front wheel of a vehicle and is selected from a drum brake and disc brake. Thus, the braking units (34 and 36) of the combined braking system of the present invention are selected from a set of disc-disc brake (both brake units are disc brakes), disc-drum brake (rear brake unit is disc brake and front brake unit is drum brake), drum-drum brake (both brake units are drum brake) and drum-disc brake (rear brake unit is drum brake and front brake unit is disc brake).

[0035] As far as the working of the combined braking system of the present invention is concerned, when the front brake lever (28) is actuated by the rider, the brake fluid travel from front master cylinder (32) to the dual CBS valve assembly (100) at the supply port (24) through the hydraulic line (40a) and then through brake fluid chamber (50b) passes to brake fluid chamber (60a) through the hydraulic passage (29) and finally from the outlet port (20) to the front disc brake (36) through the hydraulic lines (40c) without any pressure delay to apply the front disc brake (36). As the hydraulic pressure in the brake fluid chamber (60a) increases to overcome the load on the delay spring (4F), the piston assembly (PA) makes the axial movement pushing the brake fluid in the brake fluid chamber (50a) into the brake fluid chamber (60b) through the hydraulic passage (27) to apply the rear wheel disc brake (34) through the hydraulic line (40d). In this condition, the piston assembly (PB) of the dual CBS valve assembly (100) rests at its idle state (without any movement) when the front brake lever (28) is actuated. In this operating condition, the rear master cylinder (30) works as a brake fluid reservoir for the dual CBS valve assembly (100). Thus, as per the intent of the present invention, when the front brake lever (28) is actuated, the front brake (36) is getting applied first followed by the rear brake (34) leading to the combined / synchronous braking effect.

[0036] When the rear brake lever (38) is actuated by the rider, the brake fluid travel from rear master cylinder (30) to the dual CBS valve assembly (100) at the supply port (26) through the hydraulic line (40b) and then through brake fluid chamber (50a) passes to brake fluid chamber (60b) through the hydraulic passage (27) and finally from the outlet port (22) to the rear disc brake (34) through the hydraulic lines (40d) without any pressure delay to apply the rear disc brake (34). As the hydraulic pressure in the brake fluid chamber (60b) increases to overcome the pressure load on the delay spring (4R), the piston assembly (PB) makes the axial movement pushing the brake fluid in the brake fluid chamber (50b) into the brake fluid chamber (60a) through the hydraulic passage (29) to apply the front wheel disc brake (36) through the outlet port (20) and the hydraulic line (40c). In this condition, the piston assembly (PA) of the dual CBS valve assembly (100) rests at its idle state (without any axial movement) when the rear brake lever (38) is actuated. In this operating condition, the front master cylinder (32) works as a brake fluid reservoir for the dual CBS valve assembly (100). Thus, as per the intent of the present invention, when the rear brake lever (38) is actuated, the rear brake (34) is getting applied first followed by the front brake (36) leading to the combined / synchronous braking effect.

[0037] During the actuation of the dual CBS valve assembly (100), the piston assembly (PA, PB), which is the combination of respective primary piston (7F, 7R) with the respective secondary piston (5F, 5R) is moved forward once the load on the respective delay spring (4F, 4R) is overcome by the hydraulic pressure. The piston assembly (PA, PB) is moved forward to its maximum stroke in the respective brake fluid zone (50a, 50b) in response to actuation of the front brake lever (28) or the rear brake lever (38).

[0038] The unique features of the dual CBS valve assembly (100) of the present invention, viz. braking of both the wheels in response to actuation of any of the brake lever (i.e. front brake lever or rear brake lever) leading to combined braking effect, the working chamber formed between the primary piston and the closed end seal; and air vent holes provided in the valve body that opens in the pockets (70a, 70b) provided between the sliding face of the primary piston and the closed end of working chamber (W2, W4) are the novel features of the invention imparting the technical advancement. The novel construction of the dual CBS valve assembly (100) disclosed in the present invention provides a technical advantage of applying both the brakes as per the predefined delay in in response to actuation of any of the brake levers, eliminating reverse movements of the piston assembly of the valve leading to effective combined braking performance that contributes to technical advancement in technological area of the combined braking systems. Thus, the unique construction of the dual CBS valve assembly as proposed is technically superior over the conventional solutions available in the public domain. Further, the disclosed design of the dual CBS valve assembly is technically superior and imparts technical advancement fulfilling the requirement of inventive step. Further, the dual combined-braking-system of the present invention is suitable for any type of two-wheeler viz. motorcycles, scooters, etc. and it is compact in structure, cost-effective, has less complexity and is very much user friendly. ,CLAIMS:We Claim

1. A dual combined-braking-system (500) for a two-wheeler comprising of
? a rear master cylinder assembly (30) with rear brake lever (38) mounted on the left end of the handle bar in case of hand operated lever and on the chassis of the vehicle in case of foot operated lever,
? a front master cylinder assembly (32) with front brake lever (28) mounted on the right end of the handle bar,
? a dual CBS valve assembly (100),
? a rear braking unit (34) mounted on the rear wheel of a vehicle,
? a front braking unit (36) mounted on the front wheel of a vehicle, and
? a plurality of hydraulic lines (40a, 40b, 40c, 40d)
wherein,
• the dual CBS valve assembly (100) is configured to comprise a CBS a valve body (1), a pair of delay springs (4F, 4R), a pair of piston assemblies (PA, PB), a pair of fixed piston (11a, 11b), a plurality of covers (2), a plurality of seal washers (3), a pair of secondary seals (9 and 13), a pair of seal guide plates (10 and 14) and a pair of plate lock springs (15a, 15b); wherein
- the dual CBS valve body (1) is configured to have two hollow multi-step profiled cavities (C and D) bored therein having their central axes parallel to each other and said cavities (C and D) are in hydraulic communication with each other through the hydraulic passages (27 and 29);
- the cavity (C) has a plurality of stepped profiles (C1, C2, C3, C4) formed adjacent to each other in an order of decreasing diameter and a plurality of stepped profiles (C5, C6, C7) formed adjacent to each other in an order of increasing diameter progressing from an end (E1) to an end (E2) of the CBS valve body (1);
- the cavity (D) has a plurality of stepped profiles (D1, D2, D3, D4) formed adjacent to each other in an order of decreasing diameter and a plurality of stepped profiles (D5, D6, D7) formed adjacent to each other in an order of increasing diameter, progressing from an end (E2) to an end (E1) of the CBS valve body (1);
- the piston assembly (PA and PB) comprises of a primary piston (7F, 7R) and a secondary piston (5F, 5R); the primary piston (7F, 7R) is configured to have a pair of sliding faces (7P1 and 7P2) projecting out from its peripheral surface and a stepped profiled distal end (7T) to get it fitted in the secondary piston (5F, 5R); and the secondary piston (5F, 5R) is configured to have a hollow cylindrical cavity (5C) bored at its one end to receive the stepped profiled distal end (7T) of the respective primary piston (7F, 7R) and it has a pair of sliding face (5P1 and 5P2) on the outer peripheral surface of said cylindrical cavity (5C) of the secondary piston (5F and 5R);
- the delay spring (4F, 4R) is concentrically sleeved over the respective secondary piston (5F, 5R) and in between the sliding face (5P1) and the seal washer (3) fitted at the end (E1 and E2) of the dual CBS valve body (1); and
- the plate locking spring (15a, 15b) is positioned in the replenishing chamber (80a, 80b) in between the sliding face (5P2) of the secondary piston (5F, 5R) and the seal guide plate (10) to fix the position of the seal guide plate (10) and the secondary seal (9) is fitted in the stepped profile (C5, D5);
• said dual CBS valve assembly (100) is in hydraulic communication with the front and rear master cylinder assembly (32 and 30) through the hydraulic lines (40c and 40a), respectively; and
• the front brake unit (36) and rear brake unit (34) are in hydraulic communication with said CBS valve assembly (100) through the hydraulic lines (40d and 40b), respectively.

2. The dual combined braking system (500) for a two wheeled vehicle as claimed in claim 1, wherein the valve body (1) of the dual CBS valve assembly (100) is provided with an air vent hole (VH) and said air vent hole (VH) gets opened into the pocket (70a, 70b).

3. The dual combined braking system (500) for a two wheeled vehicle as claimed in claim 2, wherein
- the profile (C2) of the cavity (C) of the dual CBS valve body (1) forms a working chamber (W1) and said working chamber (W1) houses a secondary piston (5F), a delay spring (4F), a primary seal (6) and a plate lock spring (15a); said secondary piston (5F) divides the working chamber (W1) into a brake fluid chamber (50a) and a replenishing chamber (80a);
- the profile (C5) of the cavity (C) forms a working chamber (W2) and said working chamber houses a primary piston (7F) dividing the said working chamber (W2) into a brake fluid chamber (60a) and a pocket (70a); and
- the profile (C4) of the cavity (C) facilitates the primary piston (7F) to mechanically communicate the working chamber (W2) with the working chamber (W1).

4. The dual combined braking system (500) for a two wheeled vehicle as claimed in claim 3, wherein
- the profile (D2) of the cavity (D) of the dual CBS valve body (1) forms a working chamber (W3) and said working chamber (W3) houses a secondary piston (5R), a delay spring (4R), a primary seal (6) and a plate lock spring (15b); said secondary piston (5R) divides the working chamber (W3) into a brake fluid chamber (50b) and a replenishing chamber (80b);
- the profile (D5) forms a working chamber (W4) and said working chamber (W4) houses a primary piston (7R) dividing the said working chamber (W4) into a brake fluid chamber (60b) and a pocket (70b); and
- the profile (D4) of the cavity (D) facilitates the primary piston (7R) to mechanically communicate working chamber (W4) with the working chamber (W3).

5. The dual combined braking system (500) for a two wheeled vehicle as claimed in claim 4, wherein
- the brake fluid chamber (50a) of the working chamber (W1) in the cavity (C) is in hydraulic communication with the brake fluid chamber (60b) of the working chamber (W4) in the cavity (D) through the hydraulic passage (27); and
- the brake fluid chamber (60a) of the working chamber (W2) in the cavity (C) is in hydraulic communication with the brake fluid chamber (50b) of the working chamber (W3) in the cavity (D) through the hydraulic passage (29).

6. The dual combined braking system (500) for a two wheeled vehicle as claimed in claim 5, wherein the stepped profiles (C1 and C7) of the cavity (C) houses a cover (2) at the ends (E1 and E2), respectively; the stepped profiles (D7 and D1) of the cavity (D) houses a cover (2) at the ends (E1 and E2), respectively of the CBS valve body (1); the stepped profile (C3) of the cavity (C) and the stepped profile (D3) of the cavity (D) houses the secondary seal (9); and the profile (C6) of the cavity (C) and the profile (D6) of the cavity (D) houses a fixed piston (11).

7. The dual combined braking system (500) for a two wheeled vehicle as claimed in claim 6, wherein
- the valve body (1) of the dual CBS valve assembly (100) is configured to have a pair of supply ports (26 and 24) and a pair of outlet ports (20 and 22) extending out orthogonally from the outer cylindrical surface of said CBS valve body (1);
- the each of the supply ports (26 and 24) is projecting out opposite to the respective outlet port (22, 20) and is positioned at offset with each other;
- the said supply ports (26 and 24) and the outlet ports (20 and 22) are placed diagonally opposite to each other on the valve body (1);
- each of the supply ports (26 and 24) is configured to have a replenishing passage (25a, 25b) communicating with the respective replenishing chambers (80a and 80b); and
- said replenishing passages (25a, 25b) makes an acute angle (a) with the vertical axis (x-x) of the respective supply port (26, 24) and said angle (a) varies in the range of 30 to 60 degree.

8. The dual combined braking system (500) for a two wheeled vehicle as claimed in claim 7, wherein the fixed piston (11a, 11b) has a cylindrical groove (11G) bored therein to receive the shank (7s) of the primary piston (7F, 7R) and said fixed piston (11a, 11b) is rigidly fitted inside the respective profiled cavity (C6, D6) and is locked there with the help of an O-ring (12) positioned in a groove provided on the outer peripheral surface of the said fixed piston (11a, 11b); the open end of the cylindrical groove (11G) of fixed piston (11a, 11b) has a stepped profile to accommodate the secondary seal (13) therein and said seal (13) is getting locked there with the seal guide plate (14) fitted against the step portion of the profiles (C6 and C5) and (D6 and D5), respectively; the shank (7s) of the primary piston (7F, 7R) is slideably fitted inside the cylindrical groove (11G) of the respective fixed piston (11a, 11b) in such a way that the sliding faces (7P1 and 7P2) of the primary piston (7F, 7R) are getting positioned in the respective working chambers (W2, W4), respectively; the stepped profiled distal end (7T) of the primary piston (7F, 7R) is getting positioned in the respective working chamber (W1, W3), respectively after passing through the stepped profiles (C3 and C4) for the primary piston (7F) and the stepped profiles (D3 and D4) for the primary piston (7R); the positioning of the primary piston (7F, 7R) forms the first brake fluid chamber (60a, 60b) between the seal guide plate (14) and the sliding face (7P2) of the primary piston (7F, 7R) within the working chamber (W2) for the primary piston (7F) and within the working chamber (W4) for the primary piston (7R); and the primary seal (8) is fitted in between the sliding face (7P1) and the sliding face (7P2) of the respective primary piston (7F, 7R) so as to seal the leakage / passage of brake fluid in the pocket (70a, 70b) from the respective brake fluid chamber (60a, 60b).

9. The dual combined braking system (500) for a two wheeled vehicle as claimed in claim 8, wherein the secondary piston (5F, 5R) through its hollow cylindrical cavity (5C) is fitted over the stepped profiled distal end (7T) of the respective primary piston (7F, 7R) and locked there through a joining means selected from threaded joint, press-fit joint and combination thereof; the piston assembly (PA, PB) of primary piston (7F, 7R) with the respective secondary piston (5F, 5R) is configured to move axially within the respective working chambers (W1-W2, W3-W4) of the multi-step cylindrical profiled cavity (C, D) of the CBS valve body (1); the positioning of the secondary piston (5F, 5R) forms the replenishing chamber (80a, 80b) and the brake fluid chamber (50a, 50b) within the respective working chamber (W1, W3); the replenishing chamber (80a, 80b) is being formed between the rear side of the sliding face (5P2) of the respective secondary piston (5F, 5R) and the seal guide plate (10) and the brake fluid chamber (50a, 50b) is formed between the primary seal (6) and the seal washer (3) fitted in the respective stepped profile (C2, D2); the primary seal (6) is fitted in between the sliding face (5P1) and the sliding face (5P2) of the secondary piston (5F, 5R) so as to seal the leakage / passage of brake fluid from the brake fluid chamber (50a, 50b) to the respective replenishing chamber (80a, 80b); the secondary seal (9) is fitted in the profiled cavity (C3, D3) and locked there with the help of seal guide plate (10) and said seal guide plate (10) is retained at its position with the plate lock spring (15a, 15b); and the stepped profiles (C1 and D7) at end (E1) of the CBS valve body (1) and the stepped profiles (D1 and C7) at end (E2) of the CBS valve body (1) are closed with the covers (2) fitted therein.

10. The dual combined braking system (500) for a two wheeled vehicle as claimed in claim 9, wherein the rear braking unit (34) and the front braking unit (36) of the dual combined braking system (500) are selected from a disc brake, drum brake and combination thereof.

Dated this 16th day of September 2023

Sahastrarashmi Pund
Head – IPR
Endurance Technologies Ltd.

To,
The Controller of Patents,
The Patent Office, at Mumbai.