DESC:FORM-2
The Patent Act, 1970
(39 OF 1970)
&
The Patent Rules, 2006

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

BRAKE ACTUATING ASSEMBLY FOR VEHICLES

Endurance Technologies Limited
E-92, M.I.D.C. Industrial Area, Waluj,
Aurangabad - 431 136, Maharashtra, India

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

Field of Invention

[001] The present invention is related to braking system for a vehicle. More particularly, the invention is related to brake actuation assembly for two wheeled motor vehicles, preferably bikes and scooters, wherein the brake actuating assembly is capable of performing effective combined braking utilizing a simple and economical mechanism with levers and hydraulically operated components.

Background of the Invention

[002] As per motor vehicle regulations, every low powered two wheeled vehicle is now required to have a combined braking system. The braking system provided is supposed to be capable of applying both front and rear wheel brakes when only rear wheel brake lever has been actuated. This has been done with the objective of reducing road accident fatalities due to wheel locking and skidding during emergency braking conditions.

[003] Currently available hydraulic combined brake actuating assemblies that are actuated using brake pedals always need to be provided with long sets of hydraulic lines for connecting them with front and rear wheel hydraulic brakes. This increases hydraulic efficiency loss associated brake fluid pressure losses in such braking systems. Even though this disadvantage is well known and well-studied, preference is still given to hydraulic brake actuating assemblies because they allows for greater force magnification to be obtained for a given input by simple alteration of areas experiencing the pressure at the master cylinder and wheel brake cylinder ends. The use of delay valves and pressure regulatory valves also allows for easy fine tuning of time delays and adjustment of braking force distribution between the front and rear wheel brakes. Failure proofing of such hydraulic brake actuating assemblies is therefore considered more favorable than utilization of cheaper but less advantageous lever based mechanical brake actuating assemblies.

[004] Efforts at failure proofing the entire hydraulic braking system add to cost and ultimately make such hydraulic combined braking system costly. Considering these facts about existing hydraulic brake actuating assemblies, there exists need for brake actuating assembly that is not only more economical to provide but that also retain the favorable qualities of a hydraulic brake actuating assemblies.

Objectives of the Invention

[005] Therefore the main objective of the present invention is to provide a brake actuating assembly for vehicles, preferably two wheelers.

[006] Another objective of the present invention to provide a vehicle brake actuating assembly that is more economical than existing hydraulic brake actuating assemblies.

[007] Still another objective of the present invention is to provide a vehicle brake actuating assembly that can reduce the length of hydraulic line utilized in a brake pedal actuated hydraulic combined braking system.
[008] It is yet another objective of the present invention to provide a vehicle brake actuating assembly that eliminates the need for providing a delay valve or a pressure regulatory valve while retaining the functionality associated with these features of hydraulic brake actuating assemblies.

[009] It is still another objective of the present invention to provide a vehicle brake actuating assembly that can utilize more economical mechanical sub-components while still retaining the favorable force magnification feature of a hydraulic brake actuating assemblies.

Summary of the Invention

[0010] With above objectives in view, the current invention provides a vehicle brake actuating system comprising of a vehicle attachment bracket (1); a master cylinder body (5) with an outer lever attachment point (P1) and mounting points (M1 and M2); a master cylinder assembly (10) with the master cylinder body (5), a master cylinder piston (8), a piston return spring (12), a master cylinder inlet port (16) and a master cylinder outlet port (20); an actuating lever (24); a distributing lever (28); a holding spring (32); a wedge screw (36); a bracket (40); a brake actuating cable (42); a brake pedal (44); a pull rod (48); wherein, the vehicle attachment bracket (1) that has a profiled opening (1a), is fixed on the vehicle body frame (80); the master cylinder body (5) is attached to the vehicle attachment bracket (1) at mounting points (M1 and M2), and the brake pedal (44) is pivoted at a vehicle bracket attachment point (1b); the actuating lever (24) is attached to the master cylinder body (5) at the outer lever attachment point (P1) on a master cylinder flange (5a) in such a manner that the projection (24a) of the actuating lever (24) rests on the actuating portion (8a) of the piston (8) positioned within the master cylinder body (5); the pull rod (48) is attached at its one end to the brake pedal (44) at a point (P4) via a fork joint (52), and attached to the distributing lever (28) at a point (P8) via a fork joint (56); the distributing lever (28) is connected with the actuating lever (24) at a point (P12) at its one end (28a), the distributing lever (28) is connected to a brake actuating cable (42) at a point (P16) via a cable attachment bracket (42a) a cable attachment bracket (42a) and the distributing lever (28) is resting upon one end face (F1) of the wedge screw (36) at its projecting end (28b); and the bracket (40) receiving the brake actuating cable (42) is attached to the vehicle body frame (80), and the wedge screw (36) is attached to the bracket (40) on its attachment arm (40a).

[0011] Typically, a holding spring (32) is attached at its one end (32a) to the bracket (40) and to the distributing lever (28) at a point (P20) at its other end (32b). The point (P20) is optimally situated between the point (16) and the point (8) on the distributing lever (28). The pull rod (48) is parallel to the master cylinder body (5) when the brake pedal (44) has not been actuated. The brake actuating cable (42) is attached to a secondary lever (204) of a handlebar mounted front brake master cylinder assembly (200) though a bracket (208) at an attachment point (204a).

Brief Description of the Drawings

[0012] This invention is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein and advantages thereof will be better understood from the following description when read with reference to the following drawings, wherein

[0013] Figure 1 illustrates a schematic diagram of a hydraulic braking system in accordance with a conventional hydraulic combined braking system.

[0014] Figure 2 illustrates a schematic diagram of combined braking system with vehicle brake actuating assembly in accordance with the present invention.

[0015] Figure 3a illustrates front view of the vehicle brake actuating assembly in accordance with the present invention.

[0016] Figure 3b illustrates rear view of the vehicle brake actuating assembly in accordance with the present invention.

[0017] Figure 3c illustrates another embodiment of the brake actuating assembly in accordance with the present invention.

[0018] Figure 4 illustrates the vehicle brake actuating assembly in accordance with the present invention in its non-operative condition.
[0019] Figure 5 illustrates the vehicle brake actuating assembly in accordance with the present invention in its rear hydraulic circuit failed condition.

[0020] Figure 6 shows the vehicle brake actuating assembly in accordance with the present invention in its fully operative condition.

Detailed Description of the Present Invention

[0021] Referring to Fig. 1, it illustrates the schematic of a conventional hydraulic combined braking system. A conventional hydraulic combined braking system (1000) comprises of a single piston caliper (400), a three piston caliper (500), a handlebar mounted hydraulic master cylinder assembly (600), a hydraulic line (600A), a brake pedal (700), a master cylinder assembly (800), a hydraulic line (800A), a delay valve/a pressure control regulatory valve (900), a hydraulic line (900A) and a hydraulic line (900B).

[0022] In the conventional hydraulic combined braking system (1000), the brake pedal (700) is connected to the push rod (801) of the master cylinder assembly (800) at the point (J1). The output of the master cylinder assembly gets transmitted to the delay valve/pressure control regulatory valve (900) via the hydraulic line (800A). The output from the delay valve/pressure regulatory valve is transmitted to the single piston caliper (400) via the hydraulic line (900A). Another output is transmitted from the delay valve/pressure control regulatory valve (900) to the three piston caliper (500) via the hydraulic line (900B). The conventional hydraulic combined braking system (1000) can easily magnify brake pedal/lever input to the brake calipers by carefully choosing the piston effective cross sectional diameter (i.e. piston diameter and number of pistons) experiencing the pressure at both the master cylinder and the brake caliper ends. The delay valve/pressure control regulatory valve (900) can regulate the displacement of hydraulic fluid into both the hydraulic lines (900A and 900B). The actual function performed by the delay valve/pressure control regulatory valve (900) is dependent upon the type of valving mechanism actually utilized. In most cases the valve (900) tends to allow application of rear wheel brake before the front wheel brake are applied in two wheeled vehicles.

[0023] Figure 2 illustrates the schematics of a combined braking system (2000) with a vehicle brake actuating assembly (100) in accordance with an embodiment of the current invention. The brake actuating assembly (100) in accordance with an embodiment of the current invention comprises of a vehicle attachment bracket (1), a master cylinder body (5) with an outer lever attachment point (P1) and mounting points (M1 and M2), a master cylinder assembly (10) with the master cylinder body (5), a master cylinder piston (8), a piston return spring (12), a master cylinder inlet port (16) and a master cylinder outlet port (20), an actuating lever (24), a distributing lever (28), a holding spring (32), a wedge screw (36), a bracket (40), a brake actuating cable (42), a brake pedal (44) and a pull rod (48). The vehicle brake actuating assembly (100) is connected to the secondary lever (204) of a handlebar mounted front brake master cylinder assembly (200) via the brake actuating cable (42). The handlebar mounted front brake master cylinder assembly (200) is in turn connected with the brake caliper (400B) by a hydraulic line (200A). The vehicle brake actuating assembly (100) is connected to the brake caliper (400A) by a hydraulic line (10A). It is clearly determinable that a significant length of the hydraulic lines has been replaced by other mechanical components in the vehicle brake actuating assembly (100). This advantageous feature of the vehicle brake actuating assembly (100) reduces the hose hydraulic efficiency loss.

[0024] In vehicle brake actuating assembly (100), the vehicle attachment bracket (1) having a profiled opening (1a) is fixed on the vehicle body frame (80) (not specifically shown) (refer Fig. 3a). The profiled opening (1a) reduces the weight of the attachment bracket (1). The master cylinder body (5) of the master cylinder assembly (10) is attached to the vehicle attachment bracket (1) at mounting points (M1 and M2), and the brake pedal (44) is pivoted at a vehicle bracket attachment point (1b) (refer Fig. 3b). The actuating lever (24) is attached to the master cylinder body (5) at the outer lever attachment point (P1) on a master cylinder flange (5a) in such a manner that the projection (24a) of the actuating lever (24) rests on the actuating portion (8a) of the piston (8) positioned within the master cylinder body (5) (refer Fig. 3b).

[0025] The pull rod (48) utilized in the vehicle brake actuating assembly (100) is attached at its one end to the brake pedal (44) at a point (P4) via a fork joint (52), and attached to the distributing lever (28) at a point (P8) via a fork joint (56) (refer Fig. 3a and 3b). The distributing lever (28) is in turn connected with the actuating lever (24) at a point (P12) at its one end (28a). The distributing lever (28) is further connected to a brake actuating cable (42) at a point (P16) via a cable attachment bracket (42a) and the distributing lever (28) is resting upon one end face (F1) of the wedge screw (36) at its projecting end (28b). The bracket (40) receiving the brake actuating cable (42) is attached to the vehicle body frame (80), and the wedge screw (36) is attached the bracket (40) on its attachment arm (40a) by a nut (36s) as shown in Fig. 4. The pull rod (48) is almost in parallel orientation to the master cylinder body (5) when the brake pedal (44) has not been actuated.

[0026] The vehicle brake actuating assembly (100) also includes a holding spring (32) that is attached at its one end (32a) to the attachment arm (40b) of the bracket (40), and to the distributing lever (28) at a point (P20) at its other end (32b). The point (P20) where one end (32a) of the holding spring (32) is attached is optimally situated between the point (16) and the point (8) on the distributing lever (28). The brake actuating cable (42) is attached to a secondary lever (204) of a handlebar mounted front brake master cylinder assembly (200) though a bracket (208) at an attachment point (204a). The embodiment of the vehicle brake actuating assembly (100) shown in Figure 3c does not have any vehicle attachment bracket (1). Therefore the entire assembly as per the first preferred embodiment of the vehicle brake actuating assembly (100) is directly attached on the vehicle frame (80) in the second embodiment. The vehicle frame (80) serves the function of the wedge screw (36) and therefore there is also no wedge screw in the second embodiment.

[0027] Figures 4, 5 and 6 present different operative conditions of the vehicle brake actuating assembly (100). When the rider is giving no input on the brake pedal (44), the vehicle brake actuating assembly (100) is in its non-operative state as shown in Fig. 4. When the rider begins giving input to the brake pedal (44), the pull rod (48) starts pulling down the actuating lever (24) at the point (P12). The point (P16) remains in its position at this point of time due to the reaction force being setup by the holding spring (32) at the point (P20). The tilting of the distributing lever (28) is accommodated by titling of the cable attachment bracket (42a) with the minimal movement of the brake actuating cable (42). As the brake pedal (44) input received via the pull rod (48) increases, the projection (24a) that rests on the actuating portion (8a) pushes the piston (8) further into the master cylinder body (5). This displaces hydraulic fluid from within the master cylinder body (5) to the brake caliper (400A) via the outlet port (20) and the hydraulic line (10A) (refer Figs. 2 and 3b). A brake fluid reservoir (not shown) supplies the master cylinder body (5) with the hydraulic fluid till the piston (8) moves past the opening of the inlet port (16) within the master cylinder body (5). As soon the brake caliper (400A) actuation happens a significant reaction force is setup which prevents further inward movement of the piston (8) into the master cylinder body (5). This is the partially operative condition of the present invention. It must be noted that at this point of time the projecting end (28b) of the distributing lever (28) is still resting upon the wedge screw (36). This point of contact between the distributing lever (28) and the wedge screw (36) functions as a pivot point for the distributing lever (28).

[0028] After the actuation of the brake caliper (400A) starts, any further input received from the brake pedal (44) via the pull rod (48) causes the projecting end (28b) of the distributing lever (28) to lift up from the wedge screw (36). This causes the brake actuating cable (42) to be pulled downwards. As the brake actuating cable (42) is also attached to the secondary lever (204) though a bracket (208) at an attachment point (204a), this movement is transmitted to the secondary lever (204) of the handlebar mounted front brake master cylinder assembly (200). This causes hydraulic fluid to be displaced from the handlebar mounted front brake master cylinder assembly (200) to the brake caliper (400B) via hydraulic line (200A). As the input received via the pull rod (48) keeps on increasing, the fully-operative condition as shown in Fig. 6 is reached. After the fully-operative condition is reached any additional input received via the pull rod (48) is transmitted to both the brake calipers (400A and 400B) without any delay.

[0029] When the rider withdraws his input from the brake pedal (44), the piston (8) is restored to its non-operative condition under the restoring force provided by the piston return spring (12). As the piston (8) moves past the openings of the input port (16) in the master cylinder body (5), the brake fluid reservoir (not shown) allows some hydraulic fluid to flow into the hydraulic circuit leading up to the brake caliper (400A) via the hydraulic line (10A) to prevent any vacuum from being setup. The actuating lever (24) is restored to its non-operative condition by the force acting on it via the actuating portion (8a) (refer fig. 3b and 4). The distributing lever (28), the pull rod (48) and the brake pedal (44) are restored to their non-operative condition primarily under the action of the holding spring (32) and the restoring spring conventionally attached between the brake pedal (44) and the vehicle frame (80). The brake actuating cable (42) is restored to its non-operative condition primarily under the pulling force setup by the restoring spring provided for the secondary lever (204) of the handlebar mounted front brake master cylinder assembly (200) (refer fig. 3b and 4).

[0030] In the rear hydraulic circuit failed condition as shown in figure 5, initially when the brake pedal (44) is operated, the pull rod (48) pulls upon the distributing lever (28) which in turn also pulls upon the actuating lever (24). The projection (24a) of the actuating lever (24) then causes the piston (8) to be displaced into the master cylinder body (5). As the hydraulic fluid leaks out of the master cylinder body (5) in the rear hydraulic circuit failed condition, this action requires very little application of force by the motor vehicle user. Further operation of the brake pedal (44) henceforth only causes the distributing lever (28) to exert a pulling force on the spring (32) and the brake actuating cable (42). The brake actuating lever (42) when pulled by the distributing lever (28) actuates the secondary lever (204) of the handlebar mounted front brake master cylinder assembly (200). This causes operation of the brake caliper (400B) as the handlebar mounted front brake master cylinder assembly (200) displaces hydraulic fluid into it via the hydraulic line (200A).

[0031] There is no difference in the manner of functioning of the first and second embodiment of the vehicle brake actuating assembly (as illustrated in Figs. 3b and 3c respectively).

[0032] The ratio of length (AL) of the actuating lever (24) to the length (DL) of the distributing lever (28) is in the range of 1.0 < DL/AL < 1.5. This limit of the ration values represent the ideal limit in which the input from brake pedal (44) is magnified to its maximum extent by the pull rod (48), the wedge screw (36), the distributing lever (28) and the actuating lever (24) combination during partial operation condition of the brake pedal (44). In addition to the above ratio, the ratio of length (AL1) of the actuating lever (24) between the point (P1) and the projection (24a) with the length (AL2) of the actuating lever (24) between the projection (24a) and the point (P12), the range of this ratio must be 2.0 < AL1 / AL2 < 3.0. These ratios must be maintained in their specified ranges to get the ideal brake force output from the input given to the brake pedal (44).

[0033] The ratio of length (L1) of the distributing lever (28) between the point (P12) and the point (P8) with the length (L2) of the distrusting lever (28) between the point (P8) and the point (P16) is in the range of 1.0 < L1 / L2 < 1.5. Maintaining this ratio in the given range provides the ideal brake force output to the handlebar mounted front brake master cylinder assembly (200) via the brake actuating cable (42). This ratio is relevant for the transmission that happens when additional input is given to the brake pedal (44) after the partially operative condition has already been reached.

[0034] The time in which only the brake caliper (400A) receives the input from the brake pedal (44) is set by the ratio of length (L1) of the distributing lever (28) between the point (P12) and the point (P8) with the length (L3) of the distributing lever (28) between the point (P8) and the point (P20), assuming the holding spring (32) as utilized in the vehicle brake actuating assembly (100) remains the same and the other cited ratios are also not altered. The spring (32) should be connected to the distribution lever (28) between the point (P8) and the point (P16).
[0035] The technical advantages of the brake actuating assembly (100) for the vehicle as disclosed above are:
- It reduces the number of hydraulic lines significantly.
- It reduces the hydraulic pressure efficiency loss due to excessive hose length.
- The advantageous features of the hydraulic combined braking system such as delay between the application of a front and rear wheel brake are retained.
- The advantageous feature of the hydraulic combined braking system allowing fine adjustment of time delay and the proportion of force to a front and rear wheel brake are retained. The changes required to be made are minimal for any desirable setting as decided.
- The cost of the overall braking system is also reduced as there is reduction in number of hydraulic hoses and also of other components required to be failure proofed.

[0036] Therefore the vehicle brake actuating assembly (100) overcomes the disadvantages and reduces the vulnerability of the conventional brake actuating assemblies as provided in conventional hydraulic combined braking systems. Inclusion of the vehicle brake actuating assembly (100) in a combined braking system allows it to retain the advantageous characteristics of a conventional hydraulic combined braking system. ,CLAIMS:We Claim

1. A brake actuating assembly (100) for vehicles comprising of
• a vehicle attachment bracket (1),
• a master cylinder body (5) with an outer lever attachment point (P1) and mounting points (M1 and M2),
• a master cylinder assembly (10) with the master cylinder body (5), a master cylinder piston (8), a piston return spring (12), a master cylinder inlet port (16) and a master cylinder outlet port (20);
• an actuating lever (24),
• a distributing lever (28),
• a holding spring (32),
• a wedge screw (36),
• a bracket (40),
• a brake actuating cable (42),
• a brake pedal (44), and
• a pull rod (48)
wherein,
- the vehicle attachment bracket (1) has a profiled opening (1a) and is fixed on the vehicle body frame (80);
- the master cylinder body (5) is attached to the vehicle attachment bracket (1) at mounting points (M1 and M2), and the brake pedal (44) is pivoted at a vehicle bracket attachment point (1b);
- the actuating lever (24) is attached to the master cylinder body (5) at the outer lever attachment point (P1) on a master cylinder flange (5a) in such a manner that the projection (24a) of the actuating lever (24) rests on the actuating portion (8a) of the piston (8) positioned within the master cylinder body (5);
- the pull rod (48) is attached at its one end to the brake pedal (44) at a point (P4) via a fork joint (52), and attached to the distributing lever (28) at a point (P8) via a fork joint (56);
- the distributing lever (28) is connected with the actuating lever (24) at a point (P12) at its one end (28a), the distributing lever (28) is connected to a brake actuating cable (42) at a point (P16) via a cable attachment bracket (42a) and the distributing lever (28) is resting upon one end face (F1) of the wedge screw (36) at its projecting end (28b); and
- the bracket (40) receiving the brake actuating cable (42) is attached to the vehicle body frame (80), and the wedge screw (36) is attached to the bracket (40) on its attachment arm (40a).

2. A brake actuating assembly (100) for vehicles comprising of
• a master cylinder body (5) with an outer lever attachment point (P1) and mounting points (M1 and M2),
• a master cylinder assembly (10) with the master cylinder body (5), a master cylinder piston (8), a piston return spring (12), a master cylinder inlet port (16) and a master cylinder outlet port (20);
• an actuating lever (24),
• a distributing lever (28),
• a holding spring (32),
• a bracket (40),
• a brake actuating cable (42),
• a brake pedal (44), and
• a pull rod (48)
wherein,
- the master cylinder body (5) is attached to the vehicle frame (80) at mounting points (M1 and M2), and the brake pedal (44) is pivoted at the vehicle frame (80) at point (1b);
- the actuating lever (24) is attached to the master cylinder body (5) at the outer lever attachment point (P1) on a master cylinder flange (5a) in such a manner that the projection (24a) of the actuating lever (24) rests on the actuating portion (8a) of the piston (8) positioned within the master cylinder body (5);
- the pull rod (48) is attached at its one end to the brake pedal (44) at a point (P4) via a fork joint (52), and attached to the distributing lever (28) at a point (P8) via a fork joint (56);
- the distributing lever (28) is connected with the actuating lever (24) at a point (P12) at its one end (28a), the distributing lever (28) is connected to a brake actuating cable (42) at a point (P16) via a cable attachment bracket (42a) and the distributing lever (28) is resting upon the vehicle frame (80); and
- the bracket (40) receiving the brake actuating cable (42) is attached to the vehicle body frame (80).

3. The brake actuating assembly (100) as claimed in claim 1 or 2, wherein a spring (32) at its one end (32a) is attached to the bracket (40) and at its other end (32b) is attached to the distributing lever (28) at a point (P20) which is situated between the point (P8) and the point (P16).

4. The brake actuating assembly (100) as claimed in claim 3, wherein the point (P20) is optimally located between the point (16) and the point (8) on the distributing lever (28).

5. The brake actuating assembly (100) as claimed in claim 4, wherein the pull rod (48) is parallel to the master cylinder body (5) when the brake pedal (44) is not actuated.

6. The brake actuating assembly (100) as claimed in claim 5, wherein the brake actuating cable (42) is attached to a secondary lever (204) of a handlebar mounted front brake master cylinder assembly (200) though a bracket (208) at an attachment point (204a).

7. The brake actuating assembly (100) as claimed in claim 6, wherein the ratio of length (AL) of the actuating lever (24) to the length (DL) of the distributing lever (28) is in the range of 1.0 < DL/AL < 1.5.

8. The brake actuating assembly (100) as claimed in claim 7, wherein the ratio of length (AL1) of the actuating lever (24) between the point (P1) and the projection (24a), with the length (AL2) of the actuating lever (24) between the projection (24a) and the point (P12) is in range of 2.0 < AL1/AL2 < 3.0.

9. The brake actuating assembly (100) as claimed in claim 8, wherein the ratio of length (L1) of the distributing lever (28) between the point (P12) and the point (P8) with the length (L2) of the distrusting lever (28) between the point (P8) and the point (P16) is in range 1.0 < L1/L2 < 1.5.

Dated this 12th day of Nov. 2021

Sahastrarashmi Pund
Head – IPR
Endurance Technologies Ltd.

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