CLIAMS:We claim:

1. A mechanical clutch actuation system (100) for a vehicle comprising:
a support bracket (101) connectable to a firewall of the vehicle;
a pedal arm (102), wherein an upper end (102a) of said pedal arm (102) is pivotally connected to the support bracket (101), and a lower end of the pedal arm (102) is provided with a pedal pad (103); and
a pedal assistance mechanism (P) connected in between the support bracket (101) and the pedal arm (102),, said pedal assistance mechanism (P) comprises:
a stay rod (104) comprising a first end (104a) and a second end (104b), wherein the first end (104a) is slidably connected to the pedal arm (102), and the second end (104b) is configured to pass through a first plate (105) pivotally connected to the support bracket (101),
a resilient member (107) provisioned in between the first plate (105) and a second plate (106) fixed to the stay rod (104) at predetermined distance from the first plate (105), wherein the resilient member (107) is configured to apply a depression assisting force to the pedal arm (102) upon movement of said pedal arm (102) between a rest position (RP) and a transition position (TP);
wherein, the first end (104a) of the stay rod (104) slides to extend length of the stay rod (104) upon movement of the pedal arm (102) exceeding the transition position (TP).

2. The system as claimed in claim 1, wherein the upper end (102a) of the pedal arm (102) is pivotally connected to the support bracket (101) at a first pivot point (A).

3. The system as claimed in claim 1, wherein the first plate (105) is pivotally connected to the support bracket (101) at second pivot point (B).

4. The system as claimed in claim 1, wherein the first end (104a) of the stay rod (104) is configured as a piston cylinder arrangement.

5. The system as claimed in claim 4, wherein one end of the piston (104c) is pivotally connected to the pedal arm (102) at a third pivot point (C).

6. The system as claimed in claim 4, wherein other end of the piston (104c) is adapted to slide inside a cylinder (104d) provided in the stay rod (104).

7. The system as claimed in claim 1, wherein the resilient member (107) is a compression spring.

8. The system as claimed in claim 1, wherein the stay rod (104) comprises a stopper (108) fixed on the second end (104b) with predetermined distance from the first plate (105).

9. The system as claimed in claim 8, wherein the stopper (108) is fixed such that predetermined length of gap (G) is formed between the stopper (108) and the pedal bracket (5) when the pedal arm (4) is at rest position (RP).

10. A vehicle having a mechanical clutch actuation system as claimed in claim 1.

Dated this 27th Day of December, 2013 GOPINATH A. S.
IN/PA 1852
OF K&S PARTNERS
AGENT FOR THE APPLICANT

,TagSPECI:FORM 2

THE PATENTS 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 relate to a clutch actuation system, more particularly, embodiments relate 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 vehicles such as but not limiting to 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 for high torque engines, the pedal effort increases beyond acceptable levels, because of low overall actuation ratio.

In the existing clutch operating systems, a well-known assistance mechanism is used. The basic function of the assistance mechanism is to reduce the clutch pedal effort. The existing mechanism can reduce the clutch pedal effort to a considerable extent. However, there is a limitation of this mechanism because higher assistance may disallow the clutch pedal to return to its original position after the pressure imparted on the clutch pedal is removed. Since the clutch pedal effort usually remains very low during return direction compared to forward direction, which restrict the maximum assistance value.

The mechanical cultch system with pedal assistance mechanism of this type is described in U.S. Pat. No. 5165299 (herein after referred as ‘299 patent) issued to Nissan Motor Co. Ltd. The pedal assistance mechanism of ‘299 patent comprises a clutch linkage arrangement is provided with first and second assist spring units. The first assist spring unit applies a depression resisting force to a pedal arm upon rotation of the pedal arm between a rest position and a transition position, and a depression assisting force upon rotation of the pedal arm exceeding the transition position. The second assist spring unit applies a depressing assisting force to the pedal arm upon rotation of the pedal arm between the rest position and the transition position. The second assist spring unit becomes ineffective on the pedal arm when the pedal arm is in the transition position or rotated beyond the transition position.

In the pedal assistance mechanism as disclosed in the patent ‘299 both the first and second assist springs assist the depression of clutch pedal once the clutch pedal arm exceeds the transition position. This would result in higher assistance and leads to sudden/drastic movement of the clutch pedal to the final position, since the second assist spring applies depressing assisting force to pedal arm upon rotation of pedal arm between the rest position and the transition position and this assistance spring ideally should become ineffective at the transition point. Thus, causing discomfort to the driver of the automobile.

In light of foregoing discussion, it is necessary to provide a mechanical pedal actuation system with an improved 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 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.

In one non-limiting embodiment of the present disclosure there is provided a mechanical clutch actuation system for a vehicle. The system comprises a support bracket connectable to a firewall of the vehicle, and a pedal arm. An upper end of said pedal arm is pivotally connected to the support bracket, and a lower end of the pedal arm is provided with a pedal pad. The system further comprises a pedal assistance mechanism connected in between the support bracket and the pedal arm. The pedal assistance mechanism comprises a stay rod having a first end and second end. The first end is slidably connected to the pedal arm, and the second end is configured to pass through a first plate which is pivotally connected to the support bracket. A resilient member is provisioned in between the first plate and a second plate which is fixed to the stay rod at predetermined distance from the first plate. The resilient member is configured to apply a depression assisting force to the pedal arm upon movement of said pedal arm between a rest position and a transition position. Further, the first end of the stay rod slides to extend length of the stay rod upon movement of said pedal arm exceeding the transition position.

In an embodiment of the present disclosure, the upper end of the pedal arm is pivotally connected to the support bracket at a first pivot point, and the first plate is pivotally connected to the support bracket at second pivot point.

In an embodiment of the present disclosure, the first end of the stay rod configured as a piston cylinder arrangement, wherein one end of the piston is pivotally connected to the pedal arm at a third pivot point, and the other end of the piston slides inside a cylinder provided in the stay rod.

In an embodiment of the present disclosure, the resilient member is a compression spring.

In an embodiment of the present disclosure, the stay rod comprises a stopper fixed on the second end with predetermined distance from the first plate. The stopper is fixed such that predetermined length of gap is formed between the stopper and the pedal bracket when the pedal arm is at rest position.

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.

Another object of the present disclosure is to provide a mechanical clutch actuation system having the pedal assistance mechanism in which resilient member and the slidable stay rod to assist the clutch pedal actuation.

Yet another object of the present disclosure is to provide a mechanical clutch actuation system having the pedal assistance mechanism to assist the depression movement of the pedal, and 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 side view of mechanical clutch actuation system according to an embodiment of the present disclosure, with clutch pedal in rest position.

FIG. 2 illustrates mechanical clutch actuation system of FIG. 1 with clutch pedal in transition position.

FIG. 3 illustrates mechanical clutch actuation system of FIG. 1 with clutch pedal in final position.

FIG. 4 illustrates a side view of pedal assistance mechanism of mechanical clutch actuation system of the present disclosure.

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 system 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 clutch actuation system is provided with a pedal assistance mechanism comprising a resilient member, and a slidable stay rod to reduce the pedal effort by the driver to disengage the clutch, at the same time maintain the good pedal return as conventional mechanical pedal mechanism without assistance. The resilient member of the pedal assistance mechanism assist the depression of pedal once the movement of pedal exceeds from rest position to transition position. When the pedal arm travels beyond transition position the stopper stops the stay rod movement, and the first end of the stay rod slides to extend the length of the stay rod, and thus allowing the further travel of clutch pedal. The slidable stay rod allows the assistance mechanism to work in two different stages. The assistance will be given to the clutch pedal when release bearing load is high and assistance will not be given when the release bearing load is low. Hence, in this way the proposed design will provide higher assistance, and will also allow proper return of clutch pedal.

As an exemplary embodiment FIG. 1 illustrates side view of the mechanical clutch actuation system (100) with clutch pedal arm (4) in rest position. The system (100) comprises a support bracket (101) mounted on firewall [not shown] of the vehicle for supporting the clutch actuation system mechanism (100). The support bracket (101) comprises a pair of side arms (101a) extending from top of the support bracket (101) for mounting a pedal arm (102), and stay rod (104) of the system (100). The pedal arm (102) having an upper end (102a) and a lower end (102b) is pivotally mounted on the support bracket (101) at first pivot point (A) through its upper end (102a) using pivot pin [not shown], and a pedal pad (103) is mounted to a lower end (102b) of said pedal arm (102) for actuating the pedal arm (102) by the driver/operator of the vehicle.

The system (100) further comprises a pedal assistance mechanism (P) connected in between the support bracket (101) and the pedal arm (102) to assist the system (100) during clutch disengagement. The pedal assistance (P) mechanism includes a stay rod (104) having first end (104a) and second end (104b), wherein the first end (104a) of the stay rod is slidably connected to the pedal arm (102) at third pivot points (C) using a pivot pin (110). In an embodiment of the present disclosure, the first end (104a) of the stay rod (104) is configured as piston cylinder arrangement. One end of the piston (104c) comprises a circular hole which can be pivoted to the pedal arm (102) through the pivot pin [not shown], wherein other end of the piston (104c) is configured to slide inside the cylinder (104d) provided in the stay rod (104). Further, the second end of stay rod (104) is configured to pass through a first plate (105) which is pivotally connected to the support bracket (101) at the second pivot point (B). A second plate (106) is fixed to the stay rod (104) with predefined distance below the first plate (105), wherein the stay rod (104) is configured to slide up and down up to predetermined length inside the first plate (105). Further, a resilient member (107) is provisioned in between the first plate (105) and the second plate (106) of the stay rod (104) to assist the depression of the clutch pedal arm (102). In an embodiment of the present disclosure, the resilient member (107) is a compression spring, and is configured to compress the pedal arm when the stay rod (104) is moved downwards. The resilient member (107) applies a depression assisting force to the pedal arm (102) when movement of the pedal arm (102) between a rest position (RP) and a transition position (TP) [FIG.2]. When the movement of the pedal arm (102) exceeds the transition position (TP), the first end (104a) of the stay rod (104) slides to extend length of the stay rod (104) to allow the movement of the pedal arm (102) to the final position (FP) [FIG. 3].

The pedal assistance mechanism (P) further comprises a stopper (108) fixed on the second end (104b) of the stay rod (104) with predetermined distance from the first plate (105). The stopper (108) is fixed to the stay rod (104) such that predetermined length of gap (G) is formed between the stopper (108) and the pedal bracket (5) when the pedal arm (4) is at rest position (RP).

Initially, when the clutch pedal arm (102) is being displaced from its initial (rest) position (RP), the resilient member (107) assists the pedal arm (102) during such displacement between a rest position (RP) and a transition position (TP) [FIG.2]. During this operation the gap (G) between the stopper (108) and the clutch pedal bracket (101) starts reducing. Once the stopper (108) starts touching the bracket (101) i.e. upon reaching the transition position (TP), the resilient member (107) will stop assisting the pedal arm (102) depression. Upon crossing the transition position (TP), the first end (104a) of the stay rod slides to extend the overall length of the stay rod (104) to allow the movement of the pedal arm (102) till the pedal arm (102) reaches the final position (FP) [best shown in FIG. 3] thus reducing overall assistance to the system (100). The gap (G) between the stopper (108) and the pedal bracket (101) is provided in such a way that over all assistance reduces after peak pedal arm effort. Further, the slidable stay rod (104) of the present disclosure, is configured to work in two stages i.e. the assistance will be given to the clutch pedal (102) when release bearing load is high, and assistance will not be given when the release bearing load is low. Hence, in this way the proposed design will provide higher assistance to the clutch pedal (102) depression, and will also allow proper return of clutch pedal (102) to the rest position (RP).

FIG. 4 is an exemplary embodiment of the present disclosure which illustrates side view of the pedal assistance mechanism (P) of the mechanical clutch actuation system (100). The pedal assistance (P) mechanism includes a stay rod (104) having first end (104a) and second end (104b), wherein the first end (104a) of the stay rod (104) is configured as piston cylinder arrangement. One end of the piston (104c) comprises a circular hole which can be pivoted to the pedal arm (102), and the other end of the piston (104c) is configured to slide inside the cylinder (104d) provided in the stay rod (104). The second end of stay rod (104) is configured to pass through a first plate (105) which can be pivotally connected to the support bracket (101). Further, a second plate (106) is fixed to the stay rod (104) with predefined distance below the first plate (105), and the stay rod (104) is configured to slide up and down up to predetermined length inside the first plate (105). A resilient member (107) is provisioned in between the first plate (105) and the second plate (106) of the stay rod (104) to assist the depression of the clutch pedal arm (102). The pedal assistance mechanism (P) further comprises a stopper (108) fixed on the second end (104b) of the stay rod (104) with predetermined distance from the first plate (105).

Advantages:
The present disclosure provides a mechanical clutch actuation system having a pedal assistance mechanism to assist the driver during clutch engagement. This will reduce the effort of the driver greatly.

The present disclosure provides a mechanical clutch actuation system having the pedal assistance mechanism in which resilient member and the slidable stay rod which helps to reduce the clutch pedal effort.

The present disclosure provides a mechanical clutch actuation system having the pedal assistance mechanism which is simple in construction, easy to assemble and retrofitable.

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 Pedal bracket
102 Pedal arm
102a and 102b Ends of pedal arm
103 Pedal pad
104 Stay rod
104a and 104b First and second end of the stay rod
104c Piston
104d Cylinder
105 First plate
106 Second plate
107 Resilient member
108 Stopper
P Assistance mechanism
A First pivot point
B Second pivot point
C Third Pivot point
RP Rest position
TP Transition position
FP Final position