FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
Adjustable pedal assembly for improved pedal effort and feel
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 Mr. 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 mechanism of an automotive and more particularly it deals with the attachment incorporated on to the pedal assembly to provide improved feel of pedal on its actuation. It also deal with the clutch pedal assistance and more particularly it deals with attachment incorporated on to the clutch pedal assembly to provide adjustable pedal assistance along with improved feel on the actuation.
Background of the invention
The characteristics of the clutch diaphragm springs is that they are held in engaged position by strong force acting on the clutch disc sandwiched between flywheel and pressure plate. The effort on the pedal to disengage these clutch increases initial to some extent of pedal displacement and then decreases gradually replicating the characteristics of the spring on the clutch pedal. The clutch pedal assistance most of them work with compression springs. These spring mechanism attached to the pedal assembly resists pivotal movement of the clutch pedal from the start of the clutch disengagement until the effective spring force line of the spring passes the line joining the center of rotation of clutch pedal and the spring mounting points on the clutch pedal bracket after this the effective spring force changes to aid the clutch pedal in further rotation assisting the clutch disengagement. During engaging that is during return travel of the clutch pedal the spring offers resistance in opposite direction till the line joining the center of rotation of clutch pedal and the spring mounts on the pedal and pedal bracket, then the spring aid in return travel of the clutch pedal. But in existing system, when the pedal is pressed to engage or disengage the clutch the pedal assistance given by the mechanism remains constant and does change or vary with increase in pedal effort (for example the pedal effort is 12.5 kg without the any assistance mechanism then with a existing assistance mechanism the pedal effort will be 10 kg. So the pedal assistance given by the existing mechanism is 2.5 kg and it will remain same even with increase with the pedal effort with clutch wear). So this means that the pedal effort will increase to II, 12 and so on, based on the clutch wear.

Many additional mechanisms are designed and added on the pedal to decrease the peak effort on the pedal to make customer satisfied. Common design is the Over center spring, either compression or torsion type is incorporated on to the pedal in such a way that it stores energy during initial travel of the pedal and then revert it back as it passes the over center point. Thus the over center spring helps in assisting the clutch pedal in decreasing the actual force required on the pedal during actuation. But these springs are designed, so as to provide a fixed amount of pedal assistance. If these spring are designed to provide extra assistance then intended, then there will be a decline in the feel in the return travel of the pedal, resulting in sluggish pedal return, difficulty in maneuvering the vehicle which is not be acceptable. The need for greater assistance arises because of the increase in pedal effort due to wear in clutch. So an improved mechanism is needed which could be easily attached on the pedal and provide pedal assistance along with the better pedal feel wherein the pedal feel and effort could be adjusted as per the convenience of the driver.
Objective of the invention
The objective of the invention to provide a mechanism wherein pedal effort and feel can be modified as required by the driver.
Further objective of this invention is to provide a mechanism that can be easily and conveniently fitted on to the pedal and pedal bracket assembly with minor or no much modification of the system.
Brief description of the drawings
The FIGURE 1. Shows a front and side view of clutch pedal mechanism. The FIGURE 2 shows another embodiment as per the present invention. The FIGURE 3 shows the assistance curve that can be obtained with this invention and compared with the existing mechanism-Summary of the invention
Accordingly the present invention discloses an adjustable pedal assembly for improved pedal effort and feel comprising

at least one clutch pedal (2) pivotally secured on to the pedal mounting bracket
(11) by means of pedal pivot bolt (12) to rotate freely around its axis, is further
secured to the firewall;
at least one pedal pad (I) mounted on said clutch pedal (2) for applying manual
foot pressure;
at least one bottom pivot (3) an extension to the pedal (2) configured for pivoting
the pedal assistance adjustment mechanism on to the pedal (2) for adjusting the
pedal assistance.
Accordingly the present invention also discloses an adjustable pedal assembly for
improved pedal effort and feel comprising
at least one clutch pedal (2) pivotally secured on to the pedal mounting bracket
(11) by means of pedal pivot bolt (12) to rotate freely around its axis, is further
secured to the firewall;
at least one pedal pad (1) mounted on said clutch pedal (2) for applying manual
foot pressure;
at least one bottom pivot (3) an extension to the pedal (2) configured for pivoting
the pedal assistance adjustment mechanism on to the pedal (2) for adjusting the
pedal assistance;
a pressure pad (14) located on the pedal pad (1) and supported on the said pedal
pad (1) by means of extension plunger (17) supported by resilient means (16)
mounted on the pedal pad;
said resilient means (16) are configured to be compressed on application of
predetermined load on the pressure pad (14) and to further travels alongwith pedal
pad (1) on increase in load above said predetermined load value; and
at least one linear potentiometer (15) connected to bottom end of said plunger (17)
configured for providing variation in the resistance monitored by a controller (20),
on sliding of said bottom end of said plunger (17).
The limit switch (18) is provided at the end of travel to stop the supply to the motor (7) by the controller (20) to restrict any further pedal assistance adjustment. The amount of pedal assistance can achieve by rotation of knob (19).

The mechanism for improving the pedal assistance comprises of at least one motor (7) mounted on to a motion transmission device (4) to drive said motion transmission device (4); at least one adjustable piston (5) with resilient means (6) at the upper end of motion transmission device (4) and said resilient means (6) supported on a pivot bush (8); at least one pivot bush guide shaft (10) mounted to the motion transmission device (4) passing axially through said adjustable piston (5), resilient means (6) , and said pivot bush (8); and at least one pivot (9) for pivotally connecting pivot bush (8) to the pedal mounting bracket (11) such that said mechanism swivel around said pivots (3) & (9) on actuation of said pedal (2).
The motor (7) driving said adjustable piston (5) through gear assembly to linearly move said adjustable piston (5) along the shaft, thereby compressing or releasing the spring (6) to increase or decrease pedal assistance. The pedal mounting bracket (11) is further secured to the firewall inside the vehicle.
The pedal assistance is manually adjusted throughout the clutch life as per the requirement of the driver. The motor (7) is electrically connected to the switch (13) mounted on the instrument cluster inside the vehicle to operate said motor (7) in clockwise and anticlockwise direction.
The ECU is configured to restrain operation of said motor (7) when engine is in start condition to further restrain adjustment of pedal assistance in engine ON mode. The pedal assistance is maintained automatically throughout the clutch life without any human intervention.
Statement of invention
Accordingly the present invention discloses an adjustable pedal assembly for improved pedal effort and feel comprising
at least one clutch pedal (2) pivotally secured on to the pedal mounting bracket (II) by means of pedal pivot bolt (12) to rotate freely around its axis, is further secured to the firewall;

at least one pedal pad (1) mounted on said clutch pedal (2) for applying manual foot pressure;
at least one bottom pivot (3) an extension to the pedal (2) configured for pivoting the pedal assistance adjustment mechanism on to the pedal (2) for adjusting the pedal assistance.
Accordingly the present invention also discloses an adjustable pedal assembly for
improved pedal effort and feel comprising
at least one ciutch pedal (2) pivotally secured on to the pedal mounting bracket
(11) by means of pedal pivot boit (12) to rotate freely around its axis, is further
secured to the firewall;
at least one pedal pad (1) mounted on said clutch pedal (2) for applying manual
foot pressure;
at least one bottom pivot (3) an extention to the pedal (2) configured for pivoting
the pedal assistance adjustment mechanism on to the pedal (2) for adjusting the
pedal assistance;
a pressure pad (14) located on the pedal pad (1) and supported on the said pedal
pad (1) by means of extension plunger (17) supported by resilient means (16)
mounted on the pedal pad;
said resilient means (16) are configured to be compressed on application of
predetermined load on the pressure pad (14) and to further travels alongwith pedal
pad (1) on increase in load above said predetermined load value; and
at least one linear potentiometer (15) connected to bottom end of said plunger (17)
configured for providing variation in the resistance monitored by a controller (20),
on sliding of said bottom end of said plunger (17).
Detailed description of the 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.

Referring to fig 1 the clutch pedal (2) (here after referred as pedal) is firmly secured on to the pedal mounting bracket (11) by means of pedal pivot bolt (12) in such a way that the said pedal(2) can rotate freely around the axis of pedal pivot bolt (12). The manual foot pressure is applied to the pedal (2) at the lower end means of pedal pad (1) pushing the pedal (2) downward in clockwise direction with respect to fig (1) side view. The pedal mounting bracket (II) is secured to the firewall (not shown) inside the vehicle.
The pedal (2) has an extension known as bottom pivot (3). A mechanism for improving the pedal feel comprises a light weight high torque motor (7) mounted on to a light weight gear box (4) (which forms as a base to accommodate all other component of the said mechanism). The light weight gear box (4) has a projection at the bottom for pivoting it on to the pedal (2) at the bottom pivot (3). The upper end of light weight gear box (4) having a spring adjuster piston (5) which supports a spring (6) above to which consist of a pivot bush(8). The pivot bush(8), spring(6) is guided by the pivot bush guide shaft (10) which is in turn mounted to the light weight gear box(4) passing axial through the spring adjuster piston(5) connecting the light weight gear box(4). The pivot bush is connected to the pedal mounting bracket (11) through a pivot (9). With this arrangement the mechanism is able to swivel around these pivot (3) & (9) when the pedal (2) is actuated.
The light weight High torque motor (7) is electrically connected to the switch (13) mounted on the instrument cluster inside the vehicle, which can be used to turn the said light weight high torque motor (7) in clockwise and anticlockwise direction thereby compressing or expanding the spring (6) to increase or decrease assistance.
With the pedal assistance mechanism the assistance can be varied as required by the driver. The assistance can be achieved by compressing the spring (6) by means of switching the motor (7) by pressing the switch (13) on the instrument cluster. The motor(7) in turn rotates the gear(not shown) in the light weight gear box(4) the said gear box (4) has a internal mechanism (not shown) which converts the

rotational motion of the motor into linear motion which is transferred to the spring adjuster piston (5). Now the spring (6) gets compressed between the pivot bush (8) and the spring adjuster piston (5) thus increasing the resultant force between the pedal (2) and the pedal mounting bracket (10) resulting in increase of pedal assistance and reduction in the pedal effort. This would be useful for driver who wants lesser pedal effort (for example: female driver).
Also when the motor (7) is reversed the spring adjuster piston (5) instead of compressing, it releases the spring (5) thus reducing the resultant force acting between the pedal (2) and pedal bracket (11). In this case the pedal assistance is reduced and the pedal effort increases. This would be required for driver having heavy body where in he would not be comfortable with the lower pedal effort.
The curve shown in fig 3 shows the pedal assistance obtained by this invention. The dotted curve shows the pedal assistance with the conventional systems. The curves below and above the dotted curve represents the different pedal assistance obtained by the assistance mechanism and is shown for understanding the nature of assistance that can be obtained. In real terms many such infinite pedal assistance curves very closer to each other can be achieved with this invention.
The pedal assistance can only be adjusted when the engine (not shown) is off condition. This is achieved because of the switch (13) which has a special function based on signal from ECU, where in it does not operate the motor(7) when engine is started. This is provided as a safety function so that clutch pedal (2) is not restricted during engagement because of excessive assistance adjustment.
During all these pedal assistance adjustment the driver has to press the pedal (2) frequently to feel the pedal effort and to see whether the pedal is returning properly.
Fig-2 shows another embodiment as per the present invention. The working is same as that the invention in fig 1 except that pedal assistance is maintained

automatically through the clutch life without any human intervention as described earlier.
The additional embodiment includes a pressure pad (14) which is located above at the pedal pad (1) and supported on the said pedal pad(1) by means of extension called plunger(17) supported by a stiff spring (16) housed on the pedal pad . The spring (16) starts compressing only when a certain value of load is applied by foot on the pressure pad (14) when the clutch is to be disengaged. The pressure pad (14) travels with respect to pedal pad (1) when the load applied is increased. The bottom end of the plunger (17) further connected to the linear potentiometer (15) which slides and this provides a variation in the resistance which is monitored by a controller (20). The controller has electrical connection with the motor (7), limit switch (18) and the switch (13) and Adjusting and on/off knob (19).
The pedal (2) has an extension known as bottom pivot (3). A mechanism for improving the pedal feel comprises a light weight high torque motor (7) mounted on to a light weight gear box (4) (which forms as a base to accommodate all other component of the said mechanism). The light weight gear box (4) has a projection at the bottom for pivoting it on to the pedal (2) at the bottom pivot (3). The upper end of light weight gear box (4) having a spring adjuster piston (5) which supports a spring (6) above to which consist of a pivot bush (8). The pivot bush (8), spring (6) is guided by the pivot bush guide shaft (10) which is in turn mounted to the light weight gear box (4) passing axial through the spring adjuster piston (5) connecting the light weight gear box (4). The pivot bush is connected to the pedal mounting bracket (11) through a pivot (9). With this arrangement the mechanism is able to swivel around these pivot (3) & (9) when the pedal (2) is actuated.
The knob (19) can be operated in on/off condition. The pushing of this knob (19) to ON condition will actuate the pedal assistance to automatic mode where in the motor (7) controlled by controller (20) rotates either to increase or decrease the pedal assistance. The knob (19) can be rotated to vary the amount of pedal assistance required. The limit switch (18) is housed on the pedal mounting bracket

(11) gets switched On when the pedal travel is just about to completed but before touching the bottom stopper or floor (not shown) in the vehicle. The limit switch (18) is provided at the end of travel to stop the supply to the motor (7) by the controller (20) to restrict any further pedal assistance adjustment. This done so that the pedal assistance would increase unnecessarily because of the excessive load on the pressure pad (14) due to pedal (2) hitting the bottom stopper on floor (not shown) at the end of pedal travel.
Fig 4 shows the section view of the assistance variable unit of the invention The mechanism comprises a light weight high torque motor (7) mounted on to a light weight gear box (4) (which forms as a base to accommodate all other component of the said mechanism). The light weight gear box (4) has a projection at the bottom know as (4c) for pivoting it on to the pedal (2) at the bottom pivot (3). The motor (7) mounted on upper end of gear box (4) has a shaft (7a) which is extended into the gear box (4) to hold a gear (4a). This gear in turn meshes with another gear (4b) which is fixed on to piston nut (4e). The piston nut (4e) is supported on to the gear box (4) by means of a bearing (4d) preferably thrust bearing. The piston nut (4e) has internal thread which meshes with the outer threads of the spring adjuster piston (5). The upper end of the spring adjuster piston (5) supports a spring (6) above to which consist of a pivot bush (8). The pivot bush (8), spring (6) is guided by the pivot bush guide shaft (10) which is in turn mounted to the light weight gear box (4) passing axial through the spring adjuster piston (5) connecting the light weight gear box (4) base. The pivot bush is connected to the pedal mounting bracket (11) through a pivot (9) shown in fig 1. The whole assistance mechanism is able to swivel around these pivot (3) & (9) when the pedal (2) is actuated.
Working: The spring (6) assistance increases on compressing and helps in reducing the effort on the pedal (2). Now in order to increase or decrease the assistance the piston (5) needs to move up/down linearly, This is achieved by the rotaion of the piston nut (4 e) in clockwise or anticlockwise direction. The rotaion of piston nut is achieved by the electrically actuating the motor (7) which rotates

the gear (4a) mounted on motor shaft (7a) which in turn rotates the gear (4 b) which is fastened to the piston nut (5). Thus varying the assistance. The gear train shown here is a simple gear train and is for illustration of the invention and not for limiting the same. Compound and other complex gear train can be also used.
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. An adjustable pedal assembly for improved pedal effort and feel comprising
at least one clutch pedal (2) pivotally secured on to the pedal mounting bracket (11) by means of pedal pivot bolt (12) to rotate freely around its axis, is further secured to the firewall;
at least one pedal pad (I) mounted on said clutch pedal (2) for applying manual foot pressure;
at least one bottom pivot (3) an extension to the pedal (2) configured for pivoting the pedal assistance adjustment mechanism on to the pedal (2) for adjusting the pedal assistance.
2. An adjustable pedal assembly for improved pedal effort and feel comprising
at least one clutch pedal (2) pivotally secured on to the pedal mounting bracket (11) by means of pedal pivot bolt (12) to rotate freely around its axis, is further secured to the firewall;
at least one pedal pad (1) mounted on said clutch pedal (2) for applying manual foot pressure;
at least one bottom pivot (3) an extension to the pedal (2) configured for pivoting the pedal assistance adjustment mechanism on to the pedal (2) for adjusting the pedal assistance;
a pressure pad (14) located on the pedal pad (1) and supported on the said pedal pad (I) by means of extension plunger (17) supported by resilient means (16) mounted on the pedal pad;
said resilient means (16) are configured to be compressed on application of predetermined load on the pressure pad (14) and to further travels alongwith pedal pad (1) on increase in load above said predetermined load value; and
at least one linear potentiometer (15) connected to bottom end of said plunger (17) configured for providing variation in the resistance monitored by a controller (20), on sliding of said bottom end of said plunger (17).

3. The pedal assembly as claimed in claim 2 wherein said limit switch (18) is provided at the end of travel to stop the supply to the motor (7) by the controller (20) to restrict any further pedal assistance adjustment.
4. The pedal assembly as claimed in claim 2 wherein the amount of pedal assistance can achieve by rotation of knob (19).
5. The pedal assembly as claimed in claim I wherein said mechanism for improving the pedal assistance comprises of
at least one motor (7) mounted on to a motion transmission device (4) to drive said motion transmission device (4);
at least one adjustable piston (5) with resilient means (6) at the upper end of motion transmission device (4) and said resilient means (6) supported on a pivot bush (8);
at least one pivot bush guide shaft (10) mounted to the motion transmission device (4) passing axially through said adjustable piston (5), resilient means (6), and said pivot bush (8); and
at least one pivot (9) for pivotally connecting pivot bush (8) to the pedal mounting bracket (II) such that said mechanism swivel around said pivots (3) & (9) on actuation of said pedal (2).
6. The pedal assembly as claimed in claim 4 wherein said motor (7) driving said adjustable piston (5) through gear assembly to linearly move said adjustable piston (5) along the shaft, thereby compressing or releasing the spring (6) to increase or decrease pedal assistance.
7. The pedal assembly as claimed in any one of the preceding claims said pedal mounting bracket (11) is further secured to the firewall inside the vehicle.
8. The pedal assembly as claimed in claim 1 wherein pedal assistance is manually adjusted throughout the clutch life as per the requirement of the driver.

9. The pedal assembly as claimed in any one of the preceding claims said motor (7) is electrically connected to the switch (13) mounted on the instrument cluster inside the vehicle to operate said motor (7) in clockwise and anticlockwise direction.
10. The pedal assembly as claimed in any one of the preceding claims said ECU is configured to restrain operation of said motor (7) when engine is in start condition to further restrain adjustment of pedal assistance in engine ON mode.
11. The pedal assembly as claimed in claim 2 wherein said pedal assistance is maintained automatically throughout the clutch life without any human intervention.
12. The adjustable pedal assembly for improved pedal effort and feel substantially as herein described with reference to accompanying drawings.