FORM 2
THE PATENT ACT 1970 (as amended)
[39 OF 1970]
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
[See Section 10 and Rule 13]
TITLE: “A MECHANICAL CLUTCH ACTUATION SYSTEM FOR A
VEHICLE”
Name and address of the Applicant:
TATA MOTORS LIMITED, an Indian company having its registered office at
Bombay House, 24 Homi Mody Street, Hutatma Chowk, Mumbai 400 001, Maharashtra,
INDIA.
Nationality: INDIAN
The following specification particularly describes the invention the manner in which it is to be performed.

TECHNICAL FIELD
Embodiments of the present disclosure relates to a clutch actuation system, more particularly, embodiments relates to the mechanical clutch actuation system provided with pedal assistance mechanism.
BACKGROUND OF DISCLOSURE
It is well known to provide a clutch actuation system for vehicles for actuating the clutch of the vehicle in response to the actuation of a clutch pedal in the vehicle. Commonly known clutch actuation systems typically have a mechanical linkage mechanism, a clutch cable, or some combination thereof to translate the clutch pedal actuation to the clutch lever on the clutch housing. The engagement and disengagement of the clutch is determined by the manual movement of a clutch pedal, and typically controlled by the vehicle operator with his foot. The efforts to release the clutch pedal in many such applications may be greater than desired for some drivers, particularly in heavy trucks.
The pedal actuation force of the clutch is always been a concern for automobile manufacturers. A high actuation force gives fatigue to the driver. The mechanical clutch actuation system is generally used for low torque engines because of limited overall ratio available with mechanical system and limiting low pedal return force. If mechanical actuations system is used with high torque engines, the pedal effort increases beyond acceptable levels, because of low overall actuation ratio.
The conventional pedal assistance mechanisms in the mechanical actuation resist the pedal return during initial return pedal travel. This worsens the situation with mechanical clutch release systems as the clutch return release load itself is low with clutch assembly of low torque engines. The slow pedal return affects the clutch life as it increase the clutch slippage time during clutch engagement.
In light of foregoing discussion, it is necessary to provide a mechanical pedal actuation system with pedal assistance mechanism to overcome the limitations stated above.

SUMMARY OF THE DISCLOSURE
The shortcomings of the prior art are overcome and additional advantages are provided through the provision of system and method as claimed in the present disclosure.
Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.
One embodiment of the present disclosure provides a mechanical clutch actuation system of a vehicle. The system comprises a support bracket, a pedal arm pivotally mounted to said support bracket at first pivot point using suitable means. A first link consisting of an upper end and a lower end pivotally connected at predetermined location of the pedal arm through the upper end of the first link. A bell crank lever consisting of a first end, center area of pivot and a second end is pivotally connected to the lower end of the first link and is pivotally mounted to the support bracket at a second pivot point through the centre area of pivot. The system further comprises a preloaded tension spring connected between the bell crank lever and the support bracket to assist the system during clutch disengagement.
In an embodiment of the present disclosure, a stopper is provided on support bracket in the vicinity of the second end of the bell crank lever to stop the movement of the bell crank lever after predetermined travel of said bell crank lever during the clutch disengagement, and a slot is provided on the first link to facilitate sliding of the first link when the stopper restrains the movement of bell crank lever.
In an embodiment of the present disclosure, a preloaded torsion spring is mounted coaxially at the first pivot point to maintain preload on the clutch.
The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

OBJECTIVES OF THE DISCLOSURE
One object of the present disclosure is to provide a mechanical clutch actuation system having a pedal assistance mechanism to assist the driver during clutch engagement.
One object of the present disclosure is to provide a mechanical clutch actuation system having the pedal assistance mechanism in which the pedal return remains as good as conventional mechanical pedal mechanism without assistance.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
The novel features and characteristic of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:
FIG. 1 illustrates a perspective view of mechanical clutch actuation system, with clutch pedal which is in engaged condition.
FIG. 2 illustrates a side view of mechanical clutch actuation system, with clutch pedal is which in disengaged condition.
The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
The foregoing has broadly outlined the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described

hereinafter which form the subject of the claims of the disclosure. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the disclosure as set forth in the appended claims. The novel features which are believed to be characteristic of the disclosure, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.
To overcome the drawbacks mentioned in the background, a mechanical pedal actuation system is provided with a pedal assistance mechanism to reduce the pedal effort by the driver to disengage the clutch. The pedal assistance mechanism will not assist the pedal movement during last 20% travel of pedal arm to ease the return motion of the pedal arm when the clutch pedal is disengaged.
As an exemplary embodiment FIG. 1 illustrates a perspective view of mechanical clutch actuation system, with clutch pedal in pressed condition. The system (100) comprises a support bracket (101) mounted on firewall of the vehicle for supporting the clutch actuation system mechanism (100). The support bracket (101) comprises a side arm (101b) extending from top of the support bracket (101) for mounting a pedal arm (102). The pedal arm (102) having an upper end (102a) and a lower end (102b) is pivotally mounted on the support bracket (102) at first pivot point (A) through its upper end (102a) using a suitable means. And a pedal pad is mounted to a lower end (102b) of said pedal arm (102) for actuating the pedal arm (102) by the driver/user. A preloaded tension spring (106) is mounted coaxially at the first pivot point (A) to maintain preload on the clutch. A first link (103) consisting of an upper end (103a) and lower end (103b) is pivotally connected to the predetermined position of the pedal arm (102) in between the upper end (102a) and the lower end (102b) of the said pedal arm (102). The first link

(103) makes rotary pair with the pedal arm (102) i.e. when pedal arm (102) moves to and
fro the first link (103) rotates. The first link (103) provided with a slot (103c) proximal to
the lower end (103b). The lower end (103a) of the first link (103) is pivotally and slidably
connected to a first end (104a) of a bell crank lever (104). The bell crank lever (104) is
pivotally mounted onto an extended arm of the said side arm (101b) of the support
bracket (101) at second pivot point (B) through centre area of pivot (104b) of the bell
crank lever (104) using suitable means. The extended arm of the said side arm (101b) of
the support bracket (101) is welded onto the side arm (101b) to support the bell crank
lever (104). The system (100) further comprises a preloaded tension spring (105)
connected between the bell crank lever (104) and the support bracket (101) for assisting
the driver during disengaging of the clutch. One end (105a) of the tension spring (105) is
connected to a second end (104c) of the bell crank lever (104) and other end of the
tension spring (105b) is connected to a hook (101a) provided on the support bracket
(101). The tension spring (105) is mounted on the bell crank lever (104) in a preloaded
condition at the start of pedal arm (102) travel and said spring (105) assists the driver for
disengaging the clutch.
Initially, when the pedal arm (102) is in released position as shown in FIG. 2 the anchoring point of tension spring (105) on support bracket (101) and second end (104c) of the bell crank lever (104) and centre area of pivot (104b) are inline and hence no spring force of spring (105) acts on the pedal arm (102). The only load acting on the pedal arm (102) is the load from preload spring (106). During forward pedal arm (102) travel, the first link (103) actuates the bell crank lever (104). With this, the preloaded tension spring (105) pulls the bell crank lever (104) about the pivot pin (B). The angle of bell crank lever (104) is designed to resolve the component of the spring force on bell crank lever (104) such that the force component along the pedal arm (102) travel acts in the forward direction thereby reducing the actuation force required on the pedal arm (102b).
The mechanical clutch actuation system (100) further comprises a stopper (107) provided on support bracket (101) in the vicinity of the second end (104c) of the bell crank lever
(104) to stop the movement of the bell crank lever (104c) after predetermined travel of

said bell crank lever (104) during clutch disengagement. Once second end of the bell crank lever (104) hits the stopper (107), the link (103) slides in the slot (103c) available with respct to the (104 a) of bell crank lever (104), without actuating it. Thus no force of tension spring (105) acts on the pedal arm (102) towards the end of the travel. This is referred as dead travel. Because of this no assistance is provided at the end of forward travel, there is no resistance in the return travel from the tension spring (105). With this the pedal arm (104) return remains as good as conventional mechanical pedal mechanism without assistance.
The pedal assistance mechanism in the mechanical clutch actuation system (100) of the present disclosure assists the driver only up to predetermined limit i.e. up to about 75% to about 85% of the forward pedal arm (102) travel and no assistance will provided during remaining pedal arm (102) travel. This is because; assistance mechanisms resist the initial pedal arm (102) return travel. This worsens the situation with mechanical clutch release systems as the clutch return release load itself is low with clutch assembly of low torque engines. Hence, the stopper provided on the support bracket (101) restrains the motion of bell crank lever (104) during last 15% to 25% travel of pedal arm to ease the return motion of the pedal arm (104) when the pedal arm (104) is disengaged.
Equivalents
With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the

absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B."

While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
Referral Numerals:

Reference Number Description
100 Mechanical clutch actuation system
101 Support bracket
101a Hook
101b Side arm
102 Pedal arm
102a and 102b Upper and lower end of the pedal arm
103 First link
103a and 103b Upper end and lower end of the pedal arm
103c Slot in first link
104 Bell crank lever
104a and 104b First and second end of the bell crank lever
104c Centre area of pivot
105 Tension spring
105a and 105b Ends of the tension spring
106 Torsion spring
107 Stopper
A First pivot point
B Second pivot point

We Claim:
1. A mechanical clutch actuation system (100) of a vehicle comprising:
a support bracket (101) mounted on a firewall of the vehicle;
a pedal arm (102), wherein an upper end (102a) of said pedal arm (102) is pivotally mounted to said support bracket (101) at a first pivot point (A) and a pedal pad is mounted to a lower end (102b) of said pedal arm (102);
a first link (103) consisting of an upper end (103a) and a lower end (103b) pivotally connected at predetermined location of the pedal arm (102) through the upper end (103a) of the first link (103); said first link (103) having a slot (103c) proximal to the lower end (103b);
a bell crank lever (104) consisting of a first end (104a), center area of pivot (104b) and a second end (104c), said bell crank lever (104) is pivotally mounted to the support bracket (101) at a second pivot point (B) through the centre area of pivot (104b) of the bell crank lever (104); wherein the first link (103) is pivotally and slidably connected to the first end (104a) of the bell crank lever (104) through the slot (103c); and
a preloaded tension spring (105), wherein one end (105a) of the tension spring (105) is connected to the second end (104c) of the bell crank lever (104) and other end (105b) of the tension spring (105) is connected to support bracket (101) to assist the system (100) during clutch disengagement.
2. The system as claimed in claim 1 further comprises at least one stopper (106) provided on support bracket (101) in the vicinity of the second end (104c) of the bell crank lever (104) to stop the movement of the bell crank lever (104c).
3. The system as claimed in claim 2, wherein the stopper (106) restrains the movement of the bell crank lever (104) after predetermined travel of said bell crank lever (104) during the clutch disengagement.

4. The system as claimed in claim 1, wherein a slot (103c) is provided on the first link (103) to facilitate sliding of the first link (103) when the stopper (107) restrains the movement of bell crank lever (104) during clutch disengagement.
5. The system as claimed in claim 1, wherein the first link (103) is connected in between upper end (102a) and lower end (102b) of the pedal arm (102).
6. The system as claimed in claim 1, wherein a hook (101a) is provided on predetermined location of the support bracket (101) to hold the other end (105b) of the preloaded tension spring (105).
7. The system as claimed in claim 1, wherein the pedal arm (102), the first link (103), the bell crank lever (104) and the support bracket (101) are pivotably connected to each other using a member selected from atleast one of rivets, screws, pivot pins and nuts and bolts.
8. A vehicle having a mechanical clutch actuation system as claimed in claim 1.