FORM 2
THE PATENTS ACT 1970 (as amended)
[39 OF 1970]
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
[See Section 10 and Rule 13]
TITLE OF THE INVENTION
“A BRAKE ADJUSTING SYSTEM FOR A VEHICLE”
APPLICANT
TATA MOTORS LIMITED
an Indian company having its registered office
at Bombay house, 24 Homi Mody Street, Hutatma Chowk,
Mumbai 400001, Maharashtra, India. Nationality: Indian
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in
which it is to be performed.

FIELD OF THE INVENTION
The present invention relates to a brake adjusting system for a vehicle, and more particularly relates to the brake adjusting system for the vehicle including an improved automatic slack adjuster for an air brake system of the vehicle to maintain proper clearance between the brake shoe and the brake drum.
BACKGROUND OF THE INVENTION
Air braking system has been used in vehicles since years for braking purposes. The air braking system generally includes a brake chamber also termed as air chamber to which air is supplied during braking. A push rod connects the brake chamber to a slack adjuster, which further actuates an S-cam. When the brake is applied, the S-cam causes the brake shoes to expand, thereby forcing the brake shoe towards brake drum inner surface, and presses against the brake drum. Thus brake is applied to stop the vehicle. Whereas when the brake pedal is released, compressed air is vented from the chamber permitting retraction of the push rod into the brake chamber. The retracting of the push rod results in reverse pivoting of the slack adjuster back to its released position and reverse rotating of the S-cam which, in turn, retracts the brake shoe clear of the brake drum or creating the clearance back within the brake shoe and the brake drum. A predefined clearance is maintained between the brake lining of the brake shoe and the brake drum to ensure proper movement of brake shoe for braking when brake is applied and to ensure that existence of clearance between brake shoe and brake drum when no brake is applied. The slack adjuster plays a vital role in the expansion and retraction of the brake shoe via the S-cam to ensure braking and non-braking situation i.e. existence of no clearance and clearance between brake shoe and brake drum respectively.
However, due to many reasons, the clearance between the brake shoe or brake liner and the brake drum changes from its predefined values. Some of the reason includes brake overheating due to continuous application of brakes especially during highly terrain, poor braking by drivers etc. These reasons result in decrease

in the clearance between the brake shoe and the inner surface of brake drum, and sometimes even though the brake is released, the brake lining of the brake shoe remains in contact with the brake drum. This further results in decrease in vehicle speed, decrease in fuel efficiency, heavy brake noise and poor braking. Brake pulling or poor braking occurs due to zero or no clearance between brake shoe and brake drum. Brake overheating occurs frequently due to the high temperature during braking. When the temperature increases above 150 0C, brake drum expands and thus, the clearance between brake shoe & brake drum increases. The increased gap is then sensed by slack adjuster and it maintain the appropriate clearance. However, when the brake drum cools to ambient temperature, it contracts. The clearance between brake lining of the brake shoe & brake drum reduces or sometimes become zero. Hence, brake grabbing starts and further it converts into brake overheating, low fuel efficiency, low lining life and heavy brake noise.
In order to overcome above problems, the clearance between brake liner and brake drum needs to be maintained during all conditions. To maintain proper clearance, it is suggested to de-adjust the slack adjuster when the clearance between brake lining & brake drum becomes zero. Currently de-adjustment is done manually when the vehicle is in idle/stationary condition by manually rotating a worm and worm gear in the slack adjuster. Manual de-adjusting requires trained man power and proper infrastructure, which further requires cost for each time the slack adjuster is manually de-adjusted. Whereas, if de-adjustment is ignored or delayed, the brake lining continue to touch brake drum, resulting in fast wearing of brake lining and also starting brake overheating.
US 5285190 discloses an automatic slack adjuster with an operation and adjustment monitor. The device of US5285190 uses number of position detector optical switches and visual indicators. Each of these switches controls one visual indicator in the dashboard display. Different ranges are displayed on the monitor depending on different position of the brake position. The first range of brake

position would be fully released, and all visual indicators would be off to indicate this range of brake position. When the brakes are released the absence of indication by the visual indicators would confirm that the brakes are operating properly. If a visual indicator remained on when brake are released the driver would be alerted to the fact that the indicated brake position required service or repair. Though the disclosure of this invention aware the driver with the issue of the brake assembly, however does not discloses solution to the problem of existence of lack of clearance between the brake shoe and the brake drum. Instead it only informs or displays the problem to the driver, and therefore, driver has to approach a nearby mechanic or service center every time the brake assembly shows problem to manually correct the issues with the brake assembly.
Therefore, the problem to be solved is to provide an automatic slack adjuster which automatically works to ensure that the minimum or predefined clearance between the brake lining of the brake shoe and the brake drum should be maintained without manual intervention, and the problem is solved in the present invention by the brake adjusting system for a vehicle which includes a sensing unit mounted on the brake lining of the brake shoe and a motor coupled with the worm of the slack adjuster such that when the sensing unit senses continuous contact of the brake lining with the brake drum for a period greater than the predefined period, the motor rotates the worm to retract the brake shoe clear of the brake drum.
OBJECTS OF THE DISCLOSURE
One object of the present disclosure is to provide a brake adjusting system for a vehicle wherein the slack adjuster is automated to ensure clearance between the brake lining of the brake shoe and the brake drum.
Another object of the present disclosure is to provide a brake adjusting system for a vehicle wherein the slack adjuster is automated to ensure clearance between the

brake lining of the brake shoe and the brake drum by providing sensors to detect continuous contact between the brake shoe and the brake drum.
SUMMARY OF THE INVENTION
An embodiment of the present invention discloses a brake adjusting system for a vehicle comprising: a slack adjuster pivotally connected with a push rod of a brake chamber of the vehicle; an S-cam mounted on one end of a cam shaft and coupled to a brake shoe for causing expansion of said brake shoe thereof against a brake drum, and other end of said cam shaft is mounted on said slack adjuster for rotation of said cam shaft upon extension of said push rod by supply of compressed air to said brake chamber; a sensing unit mounted on a brake lining of said brake shoe to form detachable contact with said brake drum upon rotation of said cam shaft to expand said brake shoe into contact with said brake drum; and a motor coupled with a worm in said slack adjuster, said motor rotates said worm causing said slack adjuster to rotate said cam shaft in opposite direction to enable said S-cam to retract said brake shoe clear of said brake drum, wherein said sensing unit senses continuous contact of said brake shoe with said brake drum for a period greater than a predefined period, thereafter enables said motor to rotate said worm to retract said brake shoe clear of said brake drum.
In an embodiment of the present invention the sensing unit senses continuous contact of said brake shoe with said brake drum and transmits a signal to a controlling unit.
In an embodiment of the present invention the controlling unit enables said motor to rotate said worm to retract said brake shoe clear of said brake drum when said interval of continuous contact of said brake shoe with said brake drum is greater than said predefined interval.

In an embodiment of the present invention the controlling unit enables said motor to rotate said worm to retract said brake shoe clear of said brake drum when ignition and running of said vehicle is detected by said controlling unit.
In an embodiment of the present invention the motor rotates said worm to a predefined angle to achieve a predefined clearance between said brake lining of said brake shoe and said brake drum.
In an embodiment of the present invention the slack adjuster includes a pivotal arm pivotally connected to said push rod of said brake chamber and mounted on adjusting assembly housing a gear set connected with said cam shaft to rotate said cam shaft, said adjusting assembly includes a first set of drive elements, and a motion transmitting member having a second set of drive elements thereon complementary to said first set of drive elements.
In an embodiment of the present invention the motion transmitting member includes a worm shaft connected with said worm, said worm shaft is movably coupled with a worm wheel on said motion transmitting member.
In an embodiment of the present invention the worm wheel is rotatably coupled with a worm gear that compliments a third drive element of said adjusting assembly.
In an embodiment of the present invention the motor rotates said worm of said motion transmitting member to rotate said worm shaft for rotating said second drive element of said motion transmitting member to rotate said first drive element of said adjusting assembly housing said gear set, thereby rotating said cam shaft in opposite direction.

BRIEF DESCRIPTION OF DRAWINGS
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 an embodiment of the present invention depicting perspective view of a brake assembly with brake drum;
FIG. 2 illustrates an embodiment of the present invention depicting perspective rear view of the brake drum;
FIG. 3a illustrates an embodiment of the present invention depicting sectional view of the brake assembly;
FIG. 3b illustrates an embodiment of the present invention depicting perspective view of the brake assembly without motor connected to worm;
FIG. 4 illustrates an embodiment of the present invention depicting perspective view of the brake shoes;
FIG. 5 illustrates an embodiment of the present invention depicting inner view of the brake shoe of the brake assembly;
FIG. 6a illustrates an embodiment of the present invention depicting perspective view of the slack adjuster;
FIG. 6b illustrates an embodiment of the present invention depicting perspective view of the slack adjuster connected with motor;

FIG. 7a illustrates an embodiment of the present invention depicting perspective view of the brake assembly when brake is applied;
FIG. 7b illustrates an embodiment of the present invention depicting perspective view of the brake assembly when brake is released; and
FIG. 8 illustrates an embodiment of the present invention depicting flow chart for the working of the invention.
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.

Referral Numeral:
Description Reference Numeral
Brake assembly 10
Air pipe 12
Brake Drum 20
Stub axle 21
Hub assembly 22
Push rod 30
Brake chamber 32
S-cam 40
Cam shaft 42
Cam roller 44
Spring 46
Brake shoe 50

Brake lining 52
Sensing unit 60
Connecting wire 62
Slack adjuster 70
Pivotal arm 72
Gear set 74
Motion transmitting member 76
Second drive element 78
Adjusting assembly 80
First drive element 82
Third drive element 83
Worm shaft 84
Worm 86
Worm wheel 88
Worm gear 90
Supporting spring 92
Pinion assembly 94
Motor 96
Motor Shaft 98
Motor Casing 99
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.
An embodiment of the present invention discloses a brake adjusting system for a vehicle, which comprises of a brake assembly (10). The brake assembly (10) is mounted on the vehicle to ensure braking of the vehicle when brakes are applied. The brake assembly (10) comprises of brake drum (20) which is a rotating element along with the wheel of the vehicle and the brake shoes (50), which are mounted at a predefined distance from the brake drum (20).
Fig. 1 shows perspective view of the brake assembly (10). The brake assembly (10) as shown in Fig. 1 is mounted on the stub axle (21). On one side, the brake assembly (10) includes the hub assembly (22) and brake drum (20), which is then mount on the stub axle (21). On other side, a slack adjuster (70) is fixed with the cam shaft (42) of the brake assembly (10). The slack adjuster (70) is pivotally connected with a push rod (30) of a brake chamber (32) of the vehicle. When the brake is applied by driver, the air is let into the brake chamber (32) via air pipe (12) and thrusts the push rod (30) out. This in turn moves the slack adjuster (70). The slack adjuster is connected with a motor (96). Another perspective view of the brake assembly (10) is shown in Fig. 2. The Fig. 2 shows rear part of the brake assembly (10) with brake chamber (32) that receives air when brake is applied.
Fig. 3a shows an isometric view of the brake assembly (10) with centered stub axle (21). The isometric view shows hub assembly (22) connected with the stub axle (21). The brake assembly (10) comprises of a brake drum (20) which forms a

movable or detachable contact with the brake shoe (50). It is essential to maintain a predefined distance between the brake lining (52) of the brake shoe (50) and the inner surface of the brake drum (20) for proper braking. The predefined distance can be 0.3 – 1.2 mm. If the distance between the brake lining (52) and the brake drum (20) is negligible or there is no clearance between the brake lining (52) and the brake drum (20), the brake shoe (50) acts as if brake is pressed even though no brake is pressed, thereby decreasing the speed or increasing fuel consumption. In such cases slack adjuster (70) is manually operated to provide clearance.
Fig. 3b shows perspective view of the brake assembly (10) with centered stub axle (21) and outer brake drum (20). The S-cam (40) is connected with cam roller (44) which is further connected to the brake shoes (50). The S-cam (40) is shaped as “S” and the cam roller (44) rolls on the surface of the S-cam (40). When the S¬cam (40) rotates, the cam roller (44) also moves on its surface thereby resulting in expansion of the spring (46) and movement of the brake shoe (50) towards the inner surface of the brake drum (20) i.e. causing expansion of said brake shoe (50) thereof against the brake drum (20). Whereas, when the S-cam (40) rotates in other direction, the cam roller (44) also rotates on the surface of the S-cam (40), which results in compression of the spring (46), thereby pulling or retracting the brake shoe (50) away from the inner surface of the brake drum (20) i.e. retracting the brake shoe (50) clear of the brake drum (20). The S-cam (40) is at one end of the cam shaft (42). The other end of the cam shaft (42) is coupled to the slack adjuster (70). The slack adjuster (70) is pivotally connected with a push rod (30) of the brake chamber (32), such that when compressed air is supplied to the brake chamber (32), the push rod (30) extends the slack adjuster (70) thereby rotating cam shaft (42) to cause the brake shoe (50) expansion thereof against the brake drum (20). Whereas, when the compressed air is released from the brake chamber (32) i.e. when the brake is released, the push rod (30) retracts back to its original position, thereby enabling slack adjuster (70) to rotate the cam shaft (42) in opposite direction causing brake shoes (50) to clear of said brake drum (20).

Fig. 4 shows a perspective view of brake shoes (50) of the brake assembly (10). The brake shoes (50) include an outer surface and an inner surface. The outer surface of the brake shoe (50) is termed as brake lining (52) which forms the movable or detachable contact with the inner surface of the brake drum (20) when the brake is applied. The brake lining (52) is provided with sensing unit (60), which are mounted on the brake lining (52). The sensing unit (52) can be soft metals or the like capable of sensing the contact condition between the brake lining (52) and the inner surface of the brake drum (20). Also soft material cannot damage said brake drum (20) inner surface and it will wear along with friction material.
Fig. 5 shows inner surface of the brake shoes (50) of the brake assembly (10). The brake lining (52) of the brake shoes (50) is provided with the sensing unit (60), which could be mounted across its surface as desired. The sensing unit (60) also forms a detachable contact with the brake drum (20). A connecting wire (62) extends from the shoe lining (52) to transmit the signal received from the sensing unit (60). Once the sensing unit (60) senses a continuous contact of the brake lining (52) with the brake drum (20), the connecting wire (62) transmit the signal from the sensing unit (60) to the controlling unit. The controlling unit thereafter sends the signal to the motor (96).
Fig. 6a shows a perspective view of a slack adjuster (70). The slack adjuster (70) includes a pivotal arm (72), which is pivotally connected to the push rod (30) of the brake chamber (32). The pivotal arm (72) is mounted on the adjusting assembly (80). The adjusting assembly (80) houses a gear set (74), which remains fixed on its position with respect to the adjusting assembly (80). The gear set (74) includes splines on its inner circumference to receive the splines of the cam shaft (42) such that they both complement each other. When the pivotal arm (72) receives a push from the push rod (30), the pivotal arm (72) tilts forward. The pivotal arm (72) tilts or transfers the push further to the adjusting assembly (80) thereby further tilting the gear set (74). The tilting movement of the gear set (74)

results in rotation of the cam shaft (42) in one direction to enable S-cam (40) to expand brake shoe (50) for applying brake. The adjusting assembly (80) also includes a first drive element (82) which includes splines and structured on the outer circumference of the gear set (74). The first drive element (82) of the adjusting assembly (80) is structured to compliment the second drive element (78) of the motion transmitting member (76). The motion transmitting member (76) includes a worm shaft (84), a worm (86) and the second drive element (78) mounted on the worm shaft (84). When the gear set (74) tilts, the second drive element (78) rotates due to the tilting of the first drive element (82). As a result, the worm wheel (88) movably structured on the surface of the worm shaft (84) also rotates along with the worm shaft (84). The worm shaft (84) on one side includes a supporting spring (92) and on the other end connected with the worm (86). The worm shaft (84) is movably coupled with the worm wheel (88). The worm wheel (88) is rotatably coupled with the worm gear (90). The worm gear (90) is mounted on a pinion assembly (94). The pinion assembly (94) includes a gear to receive the rotation of the worm wheel (88), which results in rotation of the pinion assembly (94) and the worm gear (90). The splines of the worm gear (90) compliments the splines of the third drive element (83) movably structured on the adjusting assembly (80). The third drive element (83) provides surface for the worm gear (90) to rotate. The rotation of the worm gear (90) i.e. number of the splines moved is proportional to the distance between the brake lining (52) and the inner surface of the brake drum (20). The number of splines moved by the worm gear (90) will be larger if the distance between the brake lining (52) and the brake drum (20) is large and vice versa. This ensures that the brake is applied irrespective of the distance between the brake lining (52) and the brake drum (20). In case the gap between the brake lining (52) and the brake drum (20) reduces due to high temperature of the brake drum (20) or the like situation, the motor (96) rotates the worm (86) to a pre-defined angle to rotate the worm shaft (84) in the opposite direction. As a result, the second drive element (78) also rotates in the opposite direction, thereby causing the first drive element (82) and the gear set (74) to rotate the cam shaft (42) in the opposite direction even in the absence of

brake release condition. Thus, automatically de-adjusting the brake shoe (50) to clear of the brake drum (20).
Fig. 6b shows the slack adjuster (70) coupled with the motor (96). The motor (96) is packaged within the motor casing (99) which is coupled with the worm (86). The worm (86) is a nut or the like structure, which is connected to the slack adjuster (70) in order to reverse the movement of the cam shaft (42) in the absence of the signal to release of brake. The worm shaft (84) is movably coupled with the worm wheel (88) mounted on the motion transmitting member (76). The motor (96) is connected with the worm (86) by a motor shaft (98). When the motor (96) receives a signal from the controlling unit, it rotates the worm (86) in a particular direction to cause the slack adjuster (70) to rotate the cam shaft (42) in the opposite direction. This enables the S-cam (40) to retract the brake shoe (50) clear off the brake drum (20).
Fig. 7a and 7b show movement of the S-cam (40) when the brake is applied and released. One end of the push rod (30) is mounted on the brake chamber (32) whereas the other end is mounted on pivotal arm (72) of the slack adjuster (70). When push is received from the push rod (30), the pivotal arm (72) transfers the push to the gear set (74), which results in rotation of the cam shaft (42). The rotation of the cam shaft (42) further rotates the S-cam (40) such that the opposite extreme edges pushes the brake shoe (50) away from each other i.e. causing expansion of the brake shoe (50) and brake lining (52) thereof against the brake drum (20), as shown in Fig. 7a. When the brake is released, the push rod (30) retracts to its original position, thereby causing the pivotal arm (72) also to retract to its original position. The gear set (74) of the slack adjuster (70) accordingly comes to its original position, thereby rotating the push rod (30) in opposite direction causing the S-cam (40) to rotate in the opposite direction. As a result, the brake shoes (50) retracts back to its original position, thereby causing the brake lining (52) of the brake shoes (50) to clear of the brake drum (20) as shown in Fig. 7b. In cases, where the brake lining (52) forms a direct contact with the inner

surface of the brake drum (20), the sensing unit (60) senses such contact continuously for a period greater than the predefined period and enables the motor (96) to rotate the worm (84) in the opposite direction thereby, enabling the S-cam (40) to rotate further in the opposite direction to create the required pre-defined clearance between the brake lining (52) of the brake shoe (50) and the brake drum (20).
Fig. 8 shows a flow diagram of the working of the brake assembly (10) and the slack adjuster (70). When the brake is applied during the running condition of the vehicle, sensing unit (60) or soft metal senses the clearance between the brake lining (52) and the inner surface of the brake drum (20), if the gap is greater than the pre-defined clearance than the slack adjuster (70) automatically adjusts the gap by rotating the cam shaft (42) followed by S-cam (40) accordingly to ensure smooth braking. In cases, where the increase in the gap or clearance is due to increase in brake drum (20) temperature, the slack adjuster (70) automatically adjusts to reduce the gap between the brake lining (52) and the brake drum (20) to ensure that the gap is lowered to pre-defined clearance. However, once the brake drum (20) temperature comes to normal, the gap automatically reduces to a value lower than the pre-defined clearance. As a result, the low clearance or no clearance between the brake lining (52) and the brake drum (20) causes decrease in speed or fuel efficiency. The sensing unit (60) or soft metals, than detects the continuous contact between the brake lining (52) and the brake drum (20), and transmit the signal to the controlling unit through connecting wire (62). The controlling unit than compares the duration of the contact i.e. period for which contact is continuous between the brake drum (20) and the brake lining (52), compares it with the pre-defined period. The pre-defined period can be in the range of 1 to 3 min. The controlling unit also detects whether the vehicle is in ignition on and in running state. If the vehicle is in running state, the ignition is on and the period of contact between the brake lining (52) and the brake drum (20) is greater than the pre-defined period, the controlling unit sends signal to the motor (96) to rotate the worm (86) to a pre-defined angle in the opposite direction

causing the slack adjuster (70) to rotate the cam shaft (42) to rotate in opposite direction even if brake is already in released state, thereby de-adjusting the brake shoes (50) and maintain the proper gap i.e. maintaining predefined clearance between the brake lining (52) and the brake drum (20).

We claim:
1. A brake adjusting system for a vehicle comprising:
a slack adjuster (70) pivotally connected with a push rod (30) of a brake chamber (32) of the vehicle;
an S-cam (40) mounted on one end of a cam shaft (42) and coupled to a brake shoe (50) for causing expansion of said brake shoe (50) thereof against a brake drum (20), and other end of said cam shaft (42) is mounted on said slack adjuster (70) for rotation of said cam shaft (42) upon extension of said push rod (30) by supply of compressed air to said brake chamber (32);
a sensing unit (60) mounted on a brake lining (52) of said brake shoe (50) to form detachable contact with said brake drum (20) upon rotation of said cam shaft (42) to expand said brake shoe (50) into contact with said brake drum (20); and
a motor (96) coupled with a worm (86) in said slack adjuster (70), said motor (96) rotates said worm (86) causing said slack adjuster (70) to rotate said cam shaft (42) in opposite direction to enable said S-cam (40) to retract said brake shoe (50) clear of said brake drum (20),
wherein said sensing unit (60) senses continuous contact of said brake shoe (50) with said brake drum (20) for a period greater than a predefined period, thereafter enables said motor (96) to rotate said worm (86) to retract said brake shoe (50) clear of said brake drum (20).

2. The system as claimed in claim 1, wherein said sensing unit (60) senses continuous contact of said brake shoe (50) with said brake drum (20) and transmits a signal to a controlling unit.
3. The system as claimed in claim 2, wherein said controlling unit enables said motor (96) to rotate said worm (86) to retract said brake shoe (50) clear of said brake drum (20) when said interval of continuous contact of said brake shoe (50) with said brake drum (20) is greater than said predefined interval.
4. The system as claimed in claim 3, wherein said controlling unit enables said motor (96) to rotate said worm (86) to retract said brake shoe (50) clear of said brake drum (20) when ignition and running of said vehicle is detected by said controlling unit.
5. The system as claimed in claim 1, wherein said motor (96) rotates said worm (86) to a predefined angle to achieve a predefined clearance between said brake lining (52) of said brake shoe (50) and said brake drum (20).
6. The system as claimed in claim 1, wherein said slack adjuster (70) includes a pivotal arm (72) pivotally connected to said push rod (30) of said brake chamber (32) and mounted on an adjusting assembly (80) housing a gear set (74) detachably connected with said cam shaft (42) to rotate said cam shaft (42), said adjusting assembly includes a first drive element (82), and
a motion transmitting member (76) having a second drive element (78) thereon complementary to said first drive element (82).
7. The system as claimed in claim 6, wherein said motion transmitting
member (76) includes a worm shaft (84) connected with said worm (86),

said worm shaft (84) is movably coupled with a worm wheel (88) on said motion transmitting member (76).
8. The system as claimed in claim 7, wherein said worm wheel (88) is rotatably coupled with a worm gear (90) that compliments a third drive element (83) of said adjusting assembly (80).
9. The system as claimed in claim 8, wherein said motor (96) rotates said worm (86) of said motion transmitting member (76) to rotate said worm shaft (84) for rotating said second drive element (78) of said motion transmitting member (76) to rotate said first drive element (82) of said adjusting assembly (80) housing said gear set (74), thereby rotating said cam shaft (42) in opposite direction.