FORM 2
THE PATENT ACT, 1970
(39 OF 1970)
AND
THE PATENT RULES, 2005
COMPLETE SPECIFICATION (SEE SECTION 10 AND RULE 13)
TITLE OF THE INVENTION
A VARIABLE RATIO BRAKE PEDAL ASSEMBLY FOR VARYING PEDAL RATIO DURING A PEDAL STROKE
APPLICANT(S)
TATA MOTORS LIMITED
An Indian Company Bombay House, 24 Homi Mody Street, Hutatma Chowk, Mumbai - 400 001, Maharashtra, India.
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
[0001] The present disclosure relates to brake pedal, and more particularly relates to a variable ratio brake pedal assembly for varying pedal ratio during a pedal stroke.
BACKGROUND OF THE INVENTION
[0002] Vehicles include a brake system for controlling the movement of the
vehicle. Conventional brake systems include a brake pedal assembly for
transmitting a braking force from the vehicle operator to the wheels of the
vehicle in order to slow down the rotational movement of the wheels. The brake
pedal assembly have fixed brake pedal lever ratio. The pedal lever ratio refers to
the geometric relationship between the levers that make up
the brake pedal assembly.
[0003] Various types of variable ratio brake pedals are known in the art. FIG. 1a illustrates an existing brake pedal assembly. The existing brake pedal assembly ratio (X/Y) is constant when pedal travels from 3rd position to 1st position as shown in the FIGS. 1b and 1c. For example, high pedal effort required for 0.8 g deceleration due at a pedal lever ratio 3. More force is required (especially in large vehicles like SUV’s) to control the movement of the vehicle which demands a higher pedal ratio at the beginning of the braking action. Therefore, there remains a need of a brake pedal assembly with variable ratio.
OBJECT OF THE INVENTION
[0004] The principal object of the embodiments herein is to provide a variable ratio brake pedal assembly for varying pedal ratio during a pedal stroke.

SUMMARY OF THE INVENTION
[0005] In one aspect object is satisfied by providing a variable ratio brake pedal assembly for varying a pedal ratio during a pedal stroke. The variable ratio brake pedal assembly comprises a support bracket, a guide plate fixed on the support bracket, a brake pedal pivotally connected on the support bracket at a pivot point, a clevis is removably connected to the brake pedal using a clevis pin and a lock clip, a push rod removably connected to the clevis, and a vacuum servo removably connected to the push rod. When a force is applied on the brake pedal at a first position the clevis pin moves towards the pivot point to move the brake pedal at a second position. A distance between the clevis pin from the pivot point at the first position is less than a distance between the clevis pin from the pivot point at the second position such that the pedal ratio varies nonlinearly during the pedal stroke.
[0006] In an embodiment, the guide plate and the brake pedal comprises a slot to guide the movements of the clevis pin.
[0007] In an embodiment, the clevis is removably connected to the brake pedal through the slot of the guide plate and the slot of the brake pedal using the clevis pin and the lock clip.
[0008] In an embodiment, the clevis pin moves in the slot of the guide plate and the slot of the brake pedal when the force is applied on the brake pedal at a first position.
[0009] In an embodiment, the brake pedal is free to rotate at the pivot point at the first position.

[0010] In an embodiment, the clevis is removably connected to the push rod to adjust a shunt length.
[0011] In an embodiment, the distance between the clevis pin from the pivot point at the first position is 100 mm and wherein the distance between the clevis pin from the pivot point at the second position is 80 mm.
[0012] In an embodiment, the pedal ratio varies from 3 at the first position to 3.9 at the second position.
[0013] In an embodiment, an articulation angle of the clevis and the push rod varies from -3º to +3º by the movement of the brake pedal from the first position to the second position.
[0014] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.
BRIEF DESCRIPTION OF DRAWINGS
[0015] This connector is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:

[0016] FIGS. 1a-1c illustrates variable ratio brake pedal assembly, according to prior art;
[0017] FIG. 2 illustrates a variable ratio brake pedal assembly for varying pedal ratio during a pedal stroke, according to embodiments as disclosed herein;
[0018] FIG. 3a illustrates the variable ratio brake pedal assembly in a first position (initial resting portion), according to embodiments as disclosed herein;
[0019] FIG. 3b illustrates the variable ratio brake pedal assembly in a second position (fully depressed portion), according to embodiments as disclosed herein; and
[0020] FIG. 4 illustrates working principle of the variable ratio brake pedal assembly, according to embodiments as disclosed herein.
DETAILED DESCRIPTION OF THE INVENTION
[0021] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. The term “or” as used herein, refers to a non-exclusive or, unless otherwise indicated. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein can be practiced and to further enable those skilled in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0022] The accompanying drawings are used to help easily understand various technical features and it should be understood that the embodiments

presented herein are not limited by the accompanying drawings. As such, the present disclosure should be construed to extend to any alterations, equivalents and substitutes in addition to those which are particularly set out in the accompanying drawings. Although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are generally only used to distinguish one element from another.
[0023] Referring now to the drawings, and more particularly to FIGS. 1 through 4, there are shown preferred embodiments.
[0024] FIG. 2 illustrates a variable ratio brake pedal assembly (100) for varying pedal ratio during a pedal stroke, according to embodiments as disclosed herein. The variable ratio brake pedal assembly (100) comprising a support bracket (1), a guide plate (2), a brake pedal (3), a clevis (4), a clevis pin (5) and a lock clip (6), a push rod (7), a vacuum servo (8), and a pivot point (9). The brake pedal (3) is free to rotate at the pivot point (9) which comes to its initial resting portion by spring action (not shown in the FIG. 2). The guide plate (2) is fixed on the support bracket (1). The guide plate (2) having a slot to guide the movements of the clevis pin (5). The brake pedal (3) is pivotally connected on the support bracket (1) at the pivot point (9). The brake pedal (3) comprises a slot to guide the movements of the clevis pin (5). The clevis (4) is removably connected to the brake pedal (3) through the slot of the guide plate (2) and the slot of the brake pedal using the clevis pin (5) and the lock clip (6). The clevis (4) is removably connected to the push rod (7) to adjust a shunt length. The push rod (7) removably connected to the clevis (4) and the vacuum servo (8) removably connected to the push rod (7).
[0025] When a force is applied on the brake pedal (3) at a first position (also referred as initial resting portion) the clevis pin (5) moves towards the pivot point

(9) to move the brake pedal at a second position (also referred as fully depressed portion). The clevis pin (5) moves in the slot of the guide plate (2) and the slot of the brake pedal (3) when the force is applied on the brake pedal (3) at the first position. A distance between the clevis pin (5) from the pivot point (9) at the first position is less than a distance between the clevis pin (5) from the pivot point (9) at the second position such that the pedal ratio varies nonlinearly during the pedal stroke. The displacement of the brake pedal from the initial resting position the fully depressed portion is referred to as pedal stroke. The pedal ratio for a fixed relationship between levers is expressed as R=(X/Y).
[0026] In an embodiment, the distance between the clevis pin (5) from the pivot point (9) at the first position is 100 mm and wherein the distance between the clevis pin (5) from the pivot point (9) at the second position is 80 mm. In an embodiment, the pedal ratio varies from 3 at the first position to 3.9 at the second position.
[0027] FIG. 3a illustrates the variable ratio brake pedal assembly (100) in the first position (initial resting portion). At this position, the brake pedal lever ratio is 3 and the distance of the clevis pin (5) from the pivot point (9) is 100 mm as shown in the FIG. 3a. FIG. 3b illustrates the variable ratio brake pedal assembly (100) in the second position (fully depressed portion), according to embodiments as disclosed herein. At this position, the brake pedal lever ratio is 3.9 and the distance of (5) Clevis pin from (9) Pivot point is 82 mm as shown in the FIG. 3b. In an embodiment, an articulation angle of the clevis (4) and the push rod (7) varies from -3º to +3º by the movement of the brake pedal (3) from the first position to the second position.
[0028] FIG. 4 illustrates a working principle of the variable ratio brake pedal assembly (100), according to embodiments as disclosed herein. When pedal effort or force is applied on the brake pedal (3) at initial resting portion the

clevis pin (5) move in the slot of the guide plate (2) and the slot of the brake pedal (3). Hence this movement moves the clevis pin (5) towards the pivot point (9) on the support bracket (1) from 100 mm to 82 mm and hence the brake lever ratio change from 3 to 3.9. For example, by increasing the lever ratio from 3 to 3.9 pedal effort for 0.8 g deceleration is decreased from 12 kg to 9 kg. Improvement can be increased by modifying design of the slot of the guide plate and the slot provided in the brake pedal.
[0029] Unlike the conventional brake assembly, the proposed variable ratio brake pedal assembly (100) increases the lever ratio from 3 to 3.9 such that the pedal effort or force of the driver will be low at 0.8 g deceleration (High Braking) application. This improves the driver brake pedal feel and braking confidence along with braking performance and braking efficiency. It is appreciated that even though the brake pedal lever ratio is variable, there is no change in pedal travel. This keeps the packaging space intact.
[0030] The foregoing description of the specific embodiments will
so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

List of Reference Numerals

Sr. No. Description
1 Support bracket
2 Guide plate
3 Brake pedal
4 Clevis
5 Clevis pin
6 Lock clip
7 Push rod
8 Vacuum servo
9 Pivot point

We Claim:
1. A variable ratio brake pedal assembly (100) for varying a pedal ratio
during a pedal stroke, comprising:
a support bracket (1);
a guide plate (2) fixed on the support bracket (1);
a brake pedal (3) pivotally connected on the support bracket (1) at a pivot point (9);
a clevis (4) is connected to the brake pedal (3) using a clevis pin (5) and a lock clip (6);
a push rod (7) connected to the clevis (4); and
a vacuum servo (8) connected to the push rod (7), wherein when a force is applied on the brake pedal (3) at a first position the clevis pin (5) moves towards the pivot point (9) to move the brake pedal at a second position, wherein a distance between the clevis pin (5) from the pivot point (9) at the first position is less than a distance between the clevis pin (5) from the pivot point (9) at the second position such that the pedal ratio varies nonlinearly during the pedal stroke.
2. The variable ratio brake pedal assembly (100) as claimed in claim 1, wherein the guide plate (2) and the brake pedal (3) comprises a slot to guide the movements of the clevis pin (5).
3. The variable ratio brake pedal assembly (100) as claimed in claim 2, wherein the clevis (4) is connected to the brake pedal (3) through the slot of the guide plate (2) and the slot of the brake pedal using the clevis pin (5) and the lock clip (6).
4. The variable ratio brake pedal assembly (100) as claimed in claim 2, wherein the clevis pin (5) moves in the slot of the guide plate (2) and the

slot of the brake pedal (3) when the force is applied on the brake pedal (3) at the first position.
5. The variable ratio brake pedal assembly (100) as claimed in claim 1, wherein the brake pedal (3) is free to rotate at the pivot point (9) at the first position.
6. The variable ratio brake pedal assembly (100) as claimed in claim 1, wherein the clevis (4) is connected to the push rod (7) to adjust a shunt length.
7. The variable ratio brake pedal assembly (100) as claimed in claim 1, wherein the distance between the clevis pin (5) from the pivot point (9) at the first position is 100 mm and wherein the distance between the clevis pin (5) from the pivot point (9) at the second position is 80 mm.
8. The variable ratio brake pedal assembly (100) as claimed in claim 1, wherein the pedal ratio varies from 3 at the first position to 3.9 at the second position.
9. The variable ratio brake pedal assembly (100) as claimed in claim 1, wherein an articulation angle of the clevis (4) and the push rod (7) varies from -3º to +3º by the movement of the brake pedal (3) from the first position to the second position.