FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
PROVISIONAL SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
"LCRV MOUNTING BRACKET" 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
INVENTORS
Matin Shaikh, Madhusudhan Belsare
All Indian national
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
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FIELD OF INVENTION:
The present invention in general relates to a service braking system in an automobile and in particular relates to a mounting bracket for load compensating reduction valve of a service braking system.
BACKGROUND:
Service braking system in automobiles mainly consists of front ventilated disc brakes with twin pot caliper and rear drum brakes with auto adjuster. The hydraulic pressure is applied from a tandem master cylinder to the front and rear wheel cylinders through suitable flexible hoses. The application of hydraulic pressure pushes the pistons within the wheel cylinders outward resulting in the application of brakes. To reduce the pedal effort, a twin diaphragm vacuum booster is fitted between brake pedal and tandem master cylinder. If the vacuum booster fails, the push rod mechanically provides the braking operation. The vacuum within the braking system is generated by a vacuum pump.
While braking, the inertia force acts on the center of gravity of the vehicle. So the vertical force applied on the rear axle is decreased and the vertical load applied on the front axle increases. This effect is called load transfer and has a preponderant effect on braking.
A load compensating reduction valve (LCRV) is provided in rear brake circuit to avoid locking of rear wheels. When the brake of the vehicle is applied, the rear brake gets locked in opposition to the front brake due to the concentration and load carried on the front brake. If the rear wheels get locked, the car becomes unstable and can spin. This
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risk is considered to be most dangerous while driving. LCRV weakens the rear pressure of the rear brake so as to prevent the rear wheels from generating a spin phenomenon. Generally, LCRV is used as pressure reducing valves in automobiles like luggage vehicles. The LCRV is connected to the master cylinder and a wheel cylinder of a rear brake to vary the hydraulic ratio of front and rear brakes depending on the load carried on the vehicle.
The LCRV arrangement in conventional braking systems is not optimized i.e. there is a different LCRV design for different variant of vehicle. Also the pressure manipulating feature of LCRV is not stable, thereby causing rear wheel locking and less stability during panic braking conditions.
There is therefore a need to provide a braking system that overcomes the above mentioned problems.
OBJECTS OF THE INVENTION:
An object of the present invention relates to an optimized LCRV arrangement.
Another object of the present invention relates to a bracket for LCRV in a vehicle.
Another object of the present invention relates to avoid locking of the rear wheels of a vehicle during braking.
Yet another object of the present invention relates to enable same LCRV design for different variants of a vehicle.
Yet another object of the present invention relates to providing a stable pressure manipulating feature of LCRV.
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Yet another object of the present invention relates to providing stability during panic braking conditions.
Various modifications of the disclosed objects, as well as alternate objects of the invention, will become apparent to persons skilled in the art upon reference to the description of the invention. It is therefore contemplated that such modifications can be made without departing from the spirit or scope of the present invention as defined.
DESCRIPTION:
Fig. 1 illustrates a LCRV arrangement 100 in a vehicle. The LCRV arrangement 100 mainly comprises a LCRV unit 110, a LCRV mounting bracket 120 and a LCRV link adjustment bracket 130. The LCRV mounting bracket 120 is fixed to a chassis frame 140 of the vehicle and is connected to the LCRV unit 110. In one embodiment, the LCRV unit 110 is fastened to the LCRV mounting bracket 120 by means of bolts 150. The LCRV unit 110 can be fastened to the LCRV mounting bracket 120 by means of any fastening means as obvious to a person skilled in the art A link (not shown in figure) of the LCRV unit 110 connects the LCRV unit 110 to the LCRV link adjustment bracket 130. The LCRV link adjustment bracket 130 is further connected to the axle 160 of the vehicle. If the load on the vehicle rises, axle 160 of the vehicle rises up whereas the chassis frame 140 moves down correspondingly.
The LCRV link adjustment bracket 130 is designed in such a way that the gap between the holes of the link adjustment bracket 130 can be optimized to 20 mm. The adjustment of the gap between the holes enhances the pressure manipulating feature of the LCRV unit 110 thereby reducing the rear wheel locking. In one embodiment, an
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optimized LCRV setting gap is maintained at about 1 to 1.2 mm which is common for all variants. This is achieved by first inserting the link of the LCRV unit 110 in the first position in link adjustment bracket 130. When the link of the link adjustment bracket 130 is in first position, the optimized gap is set. After setting the gap, the link of the LCRV unit 110 is clamped in the second position in the link adjustment bracket 130.
The embodiment described above can have many variations, each of which would be obvious to a person skilled in the art. The gap between the holes of the link adjustment bracket 130 can have different dimensions based on the known engineering concepts and/or routine experimentation.
Fig. 2 illustrates a LCRV unit 110 of the LCRV arrangement 100 in a vehicle depicting LCRV setting gap 102. The LCRV unit 110 comprises a LCRV unit bracket 104, an adjusting spring 106 and a link 108. The LCRV unit bracket 104 is fastened to the LCRV mounting bracket 120 with the help of fastening means. The adjustment spring 106 of the LCRV unit 110 ensures resilient movement of the link 108 of the LCRV unit 110 between the LCRV link adjustment bracket 130 and the LCRV unit bracket 104. The LCRV setting gap 102 can be varied by adjusting the position of the link 108 of the LCRV unit 110 in the LCRV link adjustment bracket 130.
A schematic representation of an LCRV unit 110 is shown in fig. 3. The LCRV setting gap 102 is clearly depicted in the figure. The adjustment spring 106 of the LCRV unit 110 provides the resilient movement of the link 108 of the LCRV unit 110. The LCRV setting gap 102 can be varied by adjusting the position of the link 108 of the LCRV unit 110 in the LCRV link adjustment bracket 130.
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Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternate embodiments of the invention, will become apparent to persons skilled in the art upon reference to the description of the invention. It is therefore Contemplated that such modifications can be made without departing from the spirit or scope of the present invention as defined.

Dated this 18th Day of June 2007

To

The Controller of Patents

The Patent office at Mumbai

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