FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION Clutch pedal assistance mechanism
APPLICANTS
TATA MOTORS LIMITED, an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
INVENTORS
Deepak R R,
An Indian nationals
of TATA MOTORS LIMITED,
An Indian company having its registered office
At Bombay House, 24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
PREAMBLE TO THE DESCRIPTION
The following specification describes the invention and the manner in which it is performed.

FIELD OF INVENTION:
This invention relates to the foot pedal control system of a motor vehicle and more particularly to a pedal mechanism which assist and improves the pedal feel, holds the pedal if required based on the input from its related sensors during the pedal actuation. The Pedal is controlled based on the signal received form the pedal sensor and vehicle ECU interface.
BACKGROUND OF INVENTION
The clutch is a subcomponent of the transmission that is designed to engage and disengage power flow between the engine and the transmission whenever desired by driver. The clutch allows us to smoothly engage a spinning engine to a non-spinning transmission by controlling the slippage between them. The clutch system as Clutch Cover assembly consisting of a Pressure plate, diaphragm spring, friction drive straps and a disc. The disc is a critical component consisting of friction linear, cushion segment, torsions dampening springs, friction washers. It is mounted to the input shaft between the flywheel and the clutch. The actuation system may be linkage type, cables type, hydraulics type. Finally comes the pedal on which the force is applied and released in order the release and engage the clutch.
The clutch which acts as a fuse between the engine and the transmission has to under go a variety of load variation and duty cycle in its life time with the present advancement in the field of automobile, with the need for development of highly efficient, high power engines. The power from the engines is transmitted down the line to gear box by means of clutch. The clutch should be capable enough to transmit this power. In order transmit this power the clutch is associated with certain parameters while designing. The important factors that is considered in designing, is the coefficient of friction of the liner material of the clutch, Diameter of the clutch and clamp load. Since compactness is the trend of the present scenario, increase of diameter will bulge the whole transmission system. Also, friction coefficient of the liner material has its own limitation based on application and cost. The only factor which can be varied is the clamp load. By varying the clamp load the torque carrying capacity of the clutch can be increased. But when clamp load is changed it directly affects the release load. The release load is the load applied on the clutch in order to disengage/release the clutch. The

disengagement of the clutch is done either mechanically or through hydraulic means, which finally gets connected to the clutch pedal. Therefore the final outcome is the effort on the pedal and with the increase in the clamp load the effort also tend to increase.
The hydraulic actuation in clutch system is given with assistance springs on the pedal to decrease the pedal effort. But with the increase in assistance provided by these springs the pedal during its return travel becomes sluggish, and with decrease in assistance the pedal effort increases. Over a period of time the clutch wears out because of the characteristics of the diaphragm spring the pedal effort increases in the vehicle while the assistance given by the assistance spring will be the same. Also, the clutch pedal feel is important factor from the customer point of view which has to be also taken care off.
The clutch pedal riding is common problem, and it is bound to occur intentionally or unintentionally. But the effect of this would be faster wear of the clutch because of its partial engagement. The clutch tends to slip over a period of time because of clutch riding. People have tried to avoid this by means of providing indicators on the instrument cluster but no much improvement is seen.
OBJECTIVES OF THE INVENTION:
This invention deals with a mechanism which would overcome all the above mentioned drawbacks. This is done by in cooperating sensors and actuators on the pedal, which safe guards all the needs required for smooth steady clutch actuation.
The main object of this invention is to provide clutch pedal assistance mechanism which will assists the pedal whenever the effort increases to a above set value along with better pedal feel during actuation.
Another object of the invention is to avoid sudden engagement of the clutch, on the sudden release of the pedal without having the knowledge of the vehicle speed and gear engaged or disengaged.

Yet another object of the invention is to avoid clutch riding by the driver.
SUMARY OF INVENTION
According to the present invention a clutch pedal assistance mechanism comprising
at least one pedal (1) consisting of a main arm (15) with a sector gear (20) at one end and a
rotatable half pedal (15) at other end is configured to be pivoted on a pedal mounting bracket
(2) by means of pedal pivot bolt (14);
at least one resilient means mounted on a holder (11) fastened on to said main arm (15);
said resilient means (12) is configured to be compressed by a retainer (18) on said Half Pedal
(15') on pedal actuation;
at least one switch triggering lever (10) is mounted on said rotatable half pedal (15') adapted
for triggering a pedal switch (19) attached to the main arm (15);
said sector gear selectively meshed with a gear (5) mounted on the motor shaft (21) of a
motor (4) and said motor (4) is controlled by a controller (22) based on the output of said
switch (19).
The spring holder (11) has a spring adjuster screw (17) for varying the stiffness of the spring (12). The switch triggering lever (10) triggers the pedal switch (19) attached to the main arm (15) when the load in forward travel of said half pedal (15) exceeds the assembled force of said spring (12).
The pedal switch (19) is closed type in normal condition and gets disconnected when pressed. The load on said pedal (1) is acted by the clutch actuation link (16) connected by Actuation link pin (9) for transferring said load from the clutch assembly to the pedal (1) through the clutch actuation system.
The pedal sector gear (20) is mounted on said motor shaft (21) of said motor (4) by means of a bearing (6), at least one electromagnetic clutch (7) adapted for being mounted on said motor shaft (21); and at least one circular magnetic coil (8) adapted to be mounted on motor (4).

The electromagnetic clutch (7) is used to couple said motor (4) to the pedal sector gear (20) through said gear (5) when the circular magnetic coil (8) is energized.
The circular magnetic coil (8) is mounted on motor (4) concentrically with said motor shaft (21) for uniform distribution of magnetic field for uniform engagement of the Electromagnetic clutch (7).
The pedal sector gear (20) also meshes with the pinion (24) on the pedal travel sensor (3) to monitor the pedal (1) movement and direction of travel for giving feed back to a motor controller unit (22).
The pedal travel sensor (3), the pedal switch (19), the motor (4) and the circular magnetic coil (8) are electrically coupled to said controller unit (22) by means of electrical connections (27).
The controller unit (22) with controller knob (23) is interfaced with the ECU of the vehicle.
A clutch pedal assistance mechanism comprising
at least one pedal (1) pivoted on the pedal mounting bracket (2) by means of pedal pivot bolt
(14);
at least one load sensor (28) mounted on the pedal (1) adapted to sense the force of actuation
in forward travel of the pedal (1);
the clutch actuation link (13) connected to said pedal (1) by means of actuation link pin (9)
transfers the force on said pedal (1);
at least one pedal sector gear (20) which meshes with the gear (5) fastened directly on the
motor shaft (21) of the motor (4) is mounted on said pedal (1)
the pedal travel sensor (3) is mounted on the motor shaft (10);
motor assembly (4) is mounted on to said pedal mounting bracket (2) by means of mounting
bolts (14); and
said pedal travel sensor (3) and the load sensor (28) are electrically coupled to the controller
unit (22) which is in turn interfaced with the ECU of the vehicle.

The force acting on the pedal is sensed by the load sensor and feed to the controller. The controller gets the inputs from the pedal travel sensor.
STATEMENT OF INVENTION
Accordingly the present invention discloses a clutch pedal assistance mechanism comprising
at least one pedal (1) consisting of a main arm (15) with a sector gear (20) at one end and a
rotatable half pedal (15) at other end is configured to be pivoted on a pedal mounting bracket
(2) by means of pedal pivot bolt (14);
at least one resilient means mounted on a holder (11) fastened on to said main arm (15);
said resilient means (12) is configured to be compressed by a retainer (18) on said Half Pedal
(15') on pedal actuation;
at least one switch triggering lever (10) is mounted on said rotatable half pedal (15') adapted
for triggering a pedal switch (19) attached to the main arm (15);
said sector gear selectively meshed with a gear (5) mounted on the motor shaft (21) of a
motor (4) and said motor (4) is controlled by a controller (22) based on the output of said
switch (19).
A clutch pedal assistance mechanism comprising
at least one pedal (1) pivoted on the pedal mounting bracket (2) by means of pedal pivot bolt (14);
at least one load sensor (28)rnounted on the pedal (1) adapted to sense the force of actuation in forward travel of the pedal (1);
the clutch actuation link (13) connected to said pedal (1) by means of actuation link pin (9) transfers the force on said pedal (1);
at least one pedal sector gear (20) which meshes with the gear (5) fastened directly on the motor shaft (21) of the motor (4) is mounted on said pedal (1) the pedal travel sensor (3) is mounted on the motor shaft (10);
motor assembly (4) is mounted on to said pedal mounting bracket (2) by means of mounting bolts (14); and
said pedal travel sensor (3) and the load sensor (28) are electrically coupled to the controller unit (22) which is in turn interfaced with the ECU of the vehicle.

BRIEF DESCRIPTION OF INVENTION
According to present invention the pedal assistance mechanism incorporates a Motor, Pedal Travel sensor, pedal load sensor all having interface with ECU. The Pedal while actuated by human foot for disengagement of clutch, it senses the load on the pedal and pedal travel by means of the sensor provided on the pedal, this signal is monitored by the controller and instructs the motor to drive the pedal in a controlled manner based on these inputs. The controller switches the motor on and off and also, determines the motor speed and torque required for assisting the pedal.
The controller has all peripheral inputs coming from the sensors in the vehicle. The engine rpm and gearbox input is constantly monitored and based on these input the controller controls the pedal actuation speed while engaging the clutch even though if the drive suddenly disengages the clutch pedal. This helps in safe guarding the clutch from burning.
The pedal also functions when the vehicle is in moving condition and if at all the driver unknowingly rides over the clutch pedal the pedal starts to move in opposite direction pushing the driver's foot by pulsating the pedal which is felt by the driver indicative of the clutch riding, thus avoiding any clutch riding. This functioning to avoid clutch riding of the pedal occurs based on the input of the accelerator pedal and vehicle speed sensor.
The fee! of the pedal is also controlled by the motor and provides a better feel during the clutch actuation.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1 shows the front and side view of the pedal assembly with assistance mechanism as per the first embodiment of the invention.
Figure 2 shows the front and side view of the pedal assembly with assistance mechanism as per the second embodiment of the invention.

DETAILED DESCRIPTION OF INVENTION
Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the same, Fig.l shows general arrangement of clutch pedal mechanism in accordance with the invention. It consists of two main units the two piece pedal and the drive motor assembly housed in the pedal housing with a controller and sensors.
Figure 1 shows the details of mechanism. It consists of a pedal (1) pivoted on the pedal mounting bracket (2) by means of pedal pivot bolt (14). The pedal (1) is in two parts, a main arm (15) and a rotatable half pedal (15'). The half pedal(15) is pivoted on the main arm (15) by means of half pedal pivot pin (13).The main arm (15) has a spring holder(l 1) welded on to it. The spring holder (11) has a spring adjuster screw (17) for varying the stiffness of the spring (12). The spring (12) is compressed by the half pedal spring retainer (18) on the Half Pedal (15') during pedal actuation. The rotatable half pedal (15') also has a switch triggering lever (10) which triggers the pedal switch (19) attached to the main arm (15) when the load in forward travel of the half pedal (15) exceeds the assembled force of the spring (12). The pedal switch (19) is normally closed type, which means it is always in connected position when it is not pressed and gets disconnected when pressed. The load on the pedal (1) is acted by the clutch actuation link (16) connected by Actuation link pin (9). The clutch actuation link (16) transfers the load form the clutch assembly to the pedal (1) through the clutch actuation system (not shown). The pedal (1) further has a pedal sector gear(20) which meshes with a gear (5) mounted on the Motor shaft (21) of a motor (4) by means of a bearing (6).The Motor shaft (21) is further extended to accommodate the electromagnetic clutch (7) locked by lock nut (26). The electromagnetic clutch (7) is used to couple motor (4) to the pedal sector gear (20) via the gear (5) when the circular magnetic coil (8) is energized. The circular magnetic coil (8) is accommodated on motor (4) which is concentric with said motor shaft (21) so as that there is uniform distribution of magnetic field for uniform engagement of the Electromagnetic clutch (7). The complete motor assembly is mounted on to the pedal mounting bracket (2) by means of mounting bolts (25). The pedal sector gear (20) also meshes with the pinion (24) on the pedal travel sensor (3) which is used to monitor the pedal (1) movement and direction of travel for giving feed back to the controller unit (22). The pedal

travel sensor (3), the pedal switch (19), the motor (4) and the circular magnetic coil (8) is electrically coupled to the controller unit (22) by means of wire (27). The controller unit (22) having controller knob (23) is in turn interfaced with the ECU of the vehicle.
Working:
The pedal performs 4 different functions as mentioned in the objectives of the invention. But the basic of working of the component is same except the adaptation of different logic by the controller (22).
During the normal clutch actuation, the driver presses the Half pedal (15) since it is pivoted at the half pedal pivot pin (13) on the main arm (15) of the pedal (1) and supported by the spring (12) it tends to move the pedal(l) instead of turning around the half pedal pivot pin (13). But the angular movement of the pedal (J) about the pedai pivot bolt (14) is arrested by the push force of the clutch actuation link (16). So in order to actuate the pedal the driver tends apply force on the Half Pedal (15') to over come the push force of the clutch actuation link (16) connected to the pedal(l). The spring (12) is adjusted in such a way that above certain value of applied force on the half pedal (15) the spring (12) gets compressed because of this the half pedal (15') tend to rotate around the half pedal pivot pin (13) by small amount, The switch triggering lever (10) Which is a integral of the half pedal (15) also tend to rotate which in turn triggers the pedal switch (19). This variation in the pedal switch (19) position along with the signal variation obtained because of the pedal travel from pedal travel sensor (3) is continuously monitored by the controller unit (22). The controller also obtains input vehicle speed, engine speed and throttle position from the vehicle ECU (not shown in drawing). Based on these input signals the controller unit (22) activates the Motor (4) along with energizing the circular Magnetic coil (8).The energized circular Magnetic coil (8) pulls in the Electromagnetic clutch (7) and couples the Motor shaft (21) to the gear (5). The gear (5) is in positive engagement with the pedal sector gear (20) there by connecting the pedal (1) to the motor (4). The motor (4) drives the pedal (1) thus assisting the pedal (1) and without overrunning the pedal. When the force on the Half Pedal (15') drops down, the controller unit (22) disconnects the electromagnetic clutch (7) and deactivates the motor (4). During the above operations the motor (4) torque and speed are also controlled by the controller unit (22) based on the speed of the actuation and direction of actuation obtained by the travel sensor

(24) to make the pedal (1) travel smooth so that it is acceptable to the driver. The level of assistance can be varied by varying the controller knob (23) provided on the controller unit (22) adjustment.
During the return travel of the Pedal (1) the movement is controlled by the controller unit (22) based on the data input from vehicle ECU, even though if the driver tends to depress the pedal at a faster rate. The controller unit (22) controls the movement by engaging the electromagnetic clutch and driving the pedal (1) by the motor (4) in a controlled rate during its return travel thereby avoid clutch failure driveline shocks and clutch wear in the vehicle, As explained the controller unit (22) has an input from vehicle ECU and this also facilitates unnecessary actuation of the pedal (1) when vehicle in motion, thus avoiding any clutch riding during vehicle movement. The controller unit (22) acts smart by monitoring the acceleration position of the accelerator pedal in the vehicle with respect to the vehicle speed via vehicle ECU. If clutch riding is monitored based on the input from the pedal travel sensor (3) the controller unit (22) drivers the motor(4) and the activates the electromagnetic clutch(7) to drive the pedal in opposite direction with slight pedal(I) pulsation with a nominal torque indicating the removal of foot from the pedal with a beep from the controller unit (22).
Figure 2 shows the details of alternate embodiment for the assistance mechanism. It consists of a pedal (1) pivoted on the pedal mounting bracket (2) by means of pedal pivot bolt (14). The pedal (1) has a load sensor (28) mounted on the pedal (1) which senses the force of actuation in forward travel of the pedal (1). The force on the pedal (1) acted due to the clutch actuation link (13) connected to the pedal (1) by means of actuation link pin (9). The pedal (1) further has a pedal sector gear (20) which meshes with the gear (5) fastened directly on the motor shaft (21) of the motor (4). The Motor shaft (10) is further extended to accommodate the pedal travel sensor (3), The complete motor assembly (4) is mounted on to the pedal mounting bracket (2) by means of mounting bolts (14), The pedal travel sensor (3), and the load sensor (28) is electrically coupled to the controller unit (22) which is in turn interfaced with the ECU of the vehicle not shown. When the pedal is pressed the force acting on the pedal is sensed by the load sensor and feed to the controller. The controller also gets the inputs from the pedal travel sensor. Based on these inputs its controls the motor to drive the pedal for assistance. The methodology followed by the controller to assist the pedal is same as explained earlier.

The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.

We Claim:
1. A Clutch pedal assistance mechanism comprising
at least one pedal (1) consisting of a main arm (15) with a sector gear (20) at one end and a rotatable half pedal (15) at other end is configured to be pivoted on a pedal mounting bracket (2) by means of pedal pivot bolt (14);
at least one resilient means mounted on a holder (11) fastened on to said main arm (15);
said resilient means (12) is configured to be compressed by a retainer (18) on said Half Pedal (15') on pedal actuation;
at least one switch triggering lever (10) is mounted on said rotatable half pedal (15') adapted for triggering a pedal switch (19) attached to the main arm (15);
said sector gear selectively meshed with a gear (5) mounted on the motor shaft (21) of a motor (4) and said motor (4) is controlled by a controller (22) based on the output of said switch (19).
2. The clutch mechanism as claimed in claim 1, wherein said spring holder (11) has a spring adjuster screw (17) for varying the stiffness of the spring (12).
3. The clutch mechanism as claimed in claim 1, wherein said switch triggering lever (10) triggers the pedal switch (19) attached to the main arm (15) when the load in forward travel of said half pedal (15') exceeds the assembled force of said spring (12).
4. The clutch mechanism as claimed in claim 1, wherein said pedal switch (19) is closed type in normal condition and gets disconnected when pressed.
5. The clutch mechanism as claimed in claim 1, wherein the load on said pedal (1) is acted by the clutch actuation link (16) connected by Actuation link pin (9) for transferring said load from the clutch assembly to the pedal (1) through the clutch actuation system.

6. The clutch mechanism as claimed in claim 1, wherein said pedal sector gear (20) is mounted on said motor shaft (21) of said motor (4) by means of a bearing (6), at least one electromagnetic clutch (7) adapted for being mounted on said motor shaft (21); and at least one circular magnetic coil (8) adapted to be mounted on motor (4).
7. The clutch mechanism as claimed in claim 1, wherein said electromagnetic clutch (7) is used to couple said motor (4) to the pedal sector gear (20) through said gear (5) when the circular magnetic coil (8) is energized.
8. The clutch mechanism as claimed in claim 1, wherein said circular magnetic coil (8) is mounted on motor (4) concentrically with said motor shaft (21) for uniform distribution of magnetic field for uniform engagement of the Electromagnetic clutch (7).
9. The clutch mechanism as claimed in claim 1, wherein said pedal sector gear (20) also meshes with the pinion (24) on the pedal travel sensor (3) to monitor the pedal (1) movement and direction of travel for giving feed back to a motor controller unit (22).
10. The clutch mechanism as claimed in claim 1, wherein said pedal travel sensor (3), the pedal switch (19), the motor (4) and the circular magnetic coil (8) are electrically coupled to said controller unit (22) by means of electrical connections (27).
11. The clutch mechanism as claimed in claim 1, wherein said controller unit (22) with controller knob (23) is interfaced with the ECU of the vehicle.
12. A clutch pedal assistance mechanism comprising
at least one pedal (1) pivoted on the pedal mounting bracket (2) by means of pedal pivot bolt (14);

at least one load sensor (28) mounted on the pedal (1) adapted to sense the force of actuation in forward travel of the pedal (1);
the clutch actuation link (13) connected to said pedal (1) by means of actuation link pin (9) transfers the force on said pedal (1);
at least one pedal sector gear (20) which meshes with the gear (5) fastened directly on the motor shaft (21) of the motor (4) is mounted on said pedal (1)
the pedal travel sensor (3) is mounted on the motor shaft (10);
motor assembly (4) is mounted on to said pedal mounting bracket (2) by means of mounting bolts (14); and
said pedal travel sensor (3) and the load sensor (28) are electrically coupled to the controller unit (22) which is in turn interfaced with the ECU of the vehicle.
13. The clutch mechanism as claimed in claim 15, wherein said force acting on the pedal is sensed by the load sensor and feed to the controller.
14. The clutch mechanism as claimed in claim 15, wherein said controller gets the inputs from the pedal travel sensor.
15. A clutch pedal assistance mechanism substantially as herein described with reference to accompanying drawings.