FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
Steering Column Assembly
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
Prashant Thakare and Dinesh Dani
Both are 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 particularly describes the invention and the manner in which it is a performed.

FIELD OF INVENTION
This invention is related to the steering column assembly and more particularly it relates to steering column assembly for vehicles having full forward control with independent type of suspension where in rack and pinion type of steering system is adapted.
BACKGROUND OF THE INVENTION
Typically automobile steering column assembly consists of upper column body and intermediate shaft connected by universal joint. Intermediate shaft is then connected to pinion in gear assembly with the help of second universal joint. This type of arrangement is most suitable for semi forward / sedan /hatchback class of the vehicle. The said typical arrangement of said steering column assembly with two shaft and two universal joint are very simple in construction and easy to optimise for meeting safety regulation for passenger and commercial vehicles for semi forward / sedan /hatchback class.
The steering column assembly, for full forward control with independent type of suspension where in rack and pinion type of steering system is adapted, is more critical since the number of joints increase and maintaining the performance of said steering column without deterioration becomes difficult. In addition to performance of steering column, maintaining its good ergonomics also becomes difficult.
Present invention is developed to provide steering column assembly for full forward control with independent type of suspension wherein rack and pinion type of steering system is adapted.
SUMMARY OF INVENTION
The invention describes a steering column assembly for vehicles comprising; steering wheel 1, upper body column 2, first intermediate shaft 6 , second intermediate shaft 8, lower body column 10, wherein first intermediate shaft 6 and

second intermediate shaft 8 are connected to each other with the help of guide assembly 7 and coupling means. The coupling means are universal joints/couplings.
The guide assembly 7 comprises an exterior tube 13 connected to mounting plate 14 which is mounted on floor to ensure positive mounting of said guide assembly 7 on floor and avoid redundant movement of said second intermediate shaft 8, said exterior tube 13 comprising a ball and bush bearing 16 through which said second intermediate shaft 8 is dispossed to reduce friction, said second universal joint 8a is fixedly connected to said second intermediate shaft 8 whereas said third universal joint 9 is slideably fitted to said second intermediate shaft 8 for maintaining smaller tolerance band on phase angle.
The layout of said steering column assembly 1 with said upper body column 2, first intermediate shaft 6 , second intermediate shaft 8 and said lower body column 10 is "C" shaped and said assembly is provided for full forward control type of vehicles.
The upper body column 2 is connected to said first intermediate shaft 6 at an angle "b" through a first universal joint 5, said first intermediate shaft 6 is connected to second intermediate shaft 8 at an angle "c" with the help of said guide assembly 7 through a second universal joint 8a, said second intermediate shaft 8 is connected to said lower body column 10 at an angle "d" through a third universal joint 9, said lower body column 10 is connected to rack and pinion 11 through a flexible coupling 10a.
The steering wheel 1 connected to upper column body to facilitate desired steering wheel inclination 'a' with horizontal to get ergonomically good position. The first Universal joint 5 is fixedly mounted on input side and having sliding joint on output side to take care of manufacturing variation.
The coupling 10a is having sliding joint on both end in order to facilitate ease of assembling and dismantling on vehicle with said rack and pinion 11 and isolates

road excitation and provides cushioning to accommodate variation in manufacturing for said rack and gespinion mounting. The true angles "a,b,c,d" subtended by two adjacent shaft ran from 35 to 45 degrees and said universal joints operates from 0 to 60 degrees of true intended angle.
STATEMENT OF INVENTION
Accordingly the present invention describes a steering column assembly for vehicles comprising; steering wheel 1, upper body column 2, first intermediate shaft 6 , second intermediate shaft 8, lower body column 10, wherein first intermediate shaft 6 and second intermediate shaft 8 are connected to each other with the help of guide assembly 7 and coupling means.
BRIEF DESCRIPTION OF INVENTION
In accordance with the present invention, steering column assembly comprises; steering wheel 1, upper body column 2, first intermediate shaft 6 , second intermediate shaft 8, lower body column 10, wherein said upper body column 2 is connected to said first intermediate shaft 6 through a first universal joint 5, said first intermediate shaft 6 is connected to second intermediate shaft 8 with the help of said guide 7, Said first intermediate shaft 6 is connected to said second intermediate shaft 8 through second universal joint 8a, said second intermediate shaft 8 is connected to lower body column 10 by a third universal joint 9,said lower body column 10 is connected to rack & pinion 11. Said upper body column 2 is mounted on bracket 3 which is connected to body 4.
BRIEF DESCRIPTION OF DRAWINGS
Figure-01 shows steering column assembly for full forward control vehicle, in accordance with present invention.
Figure-02 shows steering column layout with in unique "C" shape in accordance with present invention.

Figure -03 shows cross sectional view of guide assembly, in accordance with present invention,
Figure -04 shows universal joints operating at large true angle, in accordance with present 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.
Now referring to Figure-01 which shows full forward control type of vehicle having cabin , steering wheel 1, upper body column 2, first intermediate shaft 6 , second intermediate shaft 8, lower body column 10 connected to rack and pinion 11 which is connected to the road wheel of the vehicle .
Now referring to figure-02 which steering column assembly comprising; steering wheel 1, upper body column 2, first intermediate shaft 6 , second intermediate shaft 8, lower body column 10, wherein said upper body column 2 is connected to said first intermediate shaft 6 through a first universal joint 5, said first intermediate shaft 6 is connected to second intermediate shaft 8 with the help of said guide assembly 7, Said first intermediate shaft 6 is connected to said second intermediate shaft 8 through second universal joint 8a, said second intermediate shaft 8 is connected to lower body column 10 by a third universal joint 9,said lower body column 10 is connected to rack & pinion 11. Said upper body column 2 is mounted on bracket 3 which is connected to body 4.
Said Steering wheel 1 is connected to upper column body 2. said steering wheel 1 is mounted to get desired steering wheel inclination 'a' with horizontal to get economically good position.

Said Upper column body 2 is connected to said first Intermediate shaft 6 by said universal joint 5. Said first Universal joint 5 is welded on input side and having sliding joint on output side to take care of manufacturing variation.
Said true angle 'b' is subtended by upper body column 2 and said first intermediate shaft 6.
Said first Intermediate shaft 6 is connected to second Intermediate shaft 8 passing through said guide assembly 7.
Said true angle 'C' is subtended by said first intermediate shaft 6 and second intermediate shaft 8.
Said first intermediate shaft 6 is connected to said second intermediate shaft 8 through second universal joint 8a.
Said second Intermediate shaft 8 is connected by a third universal joint 9 with sliding type of construction.
Said true angle 'd' is subtended by said second intermediate shaft 8 and said lower body column 10.
Output end of said second universal joint 9 connected to said rack and pinion 11 through flexible coupling 10a. The said coupling 10a is having sliding joint on both end in order to have ease of assembling and dismantling on vehicle with already fitted rack and pinion 11. The said flexible coupling 10a isolates road excitation and at the same time it provides cushion to accommodate variation in manufacturing for said rack and pinion mounting.
Said flexible coupling 10a is provided between said rack and pinion 11 and said lower body column 10.
Now referring to figure-03 which shows guide assembly 7. The said guide assembly 7 consists of exterior tube 13 welded to mounting plate 14. said mounting

plate 14 bolted to floor using hex screw 15. This ensures positive mounting of said guide assembly 7 on floor and avoids redundant movement of said second intermediate shaft 8. Said second intermediate shaft 8 passing through a ball bearing and bush bearing 16. This type of bearing and bush combination is helpful to reduce friction as well as the cost. Said third universal joint 9 is slide fitted to said second intermediate shaft 8 whereas universal joint connecting first intermediate shaft 6 and second intermediate shaft 8 is welded to said second intermediate shaft 8 for maintaining smaller tolerance band on phase angle.
Figure-04 shows the details of universal joint having yoke 17 and yoke 18 connected by standard spider 19. Wider and longer yokes 17 and 18 provides wider operating angles for the universal joint. Joint yoke are either welded to said intermediate shafts or bolted by screw 20.
Layout of the steering column assembly 1 with said upper body column 2, first intermediate shaft 6 , second intermediate shaft 8 and said lower body column 10, is "C" shaped.
The said True angles "a,b,c,d" subtended by two adjacent shaft ranges from 35 to 45 degree.
Universal joints which are operating from 0 to 60 degrees of true intended angle Said guide assembly 7 having a bearing and bush type of design which is fixedly mounted on to floor of vehicle. Said guide assembly 7 guides said second intermediate shaft 8.
Torque transferred from said steering wheel 1 to said rack and pinion 11 without fluctuation is achieved by providing phase angle. Variation in phase angle manufacturing is achieved by combination of welded and sliding joints.
Said torque transferred from steering wheel 1 to rack and pinion 11 without exceeding fluctuation by 2% is obtained by phasing universal joints.

Mounting bracket 3 is provided for upper body column 2 mounting which contributes to meet safety regulation related to steering column intrusion.
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 steering column assembly for vehicles comprising; steering wheel (1), upper body column (2), first intermediate shaft (6) , second intermediate shaft (8), lower body column (10), wherein first intermediate shaft (6) and second intermediate shaft (8) are connected to each other with the help of guide assembly (7) and coupling means.
2. The assembly as claimed in claim 1, wherein said coupling means are universal joints/couplings.
3. The assembly as claimed in claim 1, wherein said guide assembly (7) comprises an exterior tube (13) connected to mounting plate (14) which is mounted on floor to ensure positive mounting of said guide assembly (7) on floor and avoid redundant movement of said second intermediate shaft (8), said exterior tube (13) comprising a ball and bush bearing (16) through which said second intermediate shaft (8) is disposed to reduce friction, said second universal joint (8a) is fixedly connected to said second intermediate shaft (8) whereas said third universal joint (9) is slideably fitted to said second intermediate shaft (8) for maintaining smaller tolerance band on phase angle.
4. The assembly as claimed in claim 1, wherein layout of said steering column assembly (1) with said upper body column (2), first intermediate shaft (6), second intermediate shaft (8) and said lower body column (10) is "C" shaped and said assembly is provided for full forward control type of vehicles.
5. The assembly as claimed in claim 1, wherein said upper body column (2) is connected to said first intermediate shaft (6) at an angle "b" through a first universal joint (5), said first intermediate shaft (6) is connected to second intermediate shaft (8) at an angle "c" with the help of said guide assembly (7) through a second universal joint (8a), said second intermediate shaft (8) is connected to said lower body column (10) at an angle "d" through a third

universal joint (9), said lower body column (10) is connected to rack and pinion (11) through a flexible coupling (10a).
6. The assembly as claimed in claim 1, wherein said steering wheel (1) connected to upper column body to facilitate desired steering wheel inclination 'a' with horizontal to get ergonomically good position.
7. The assembly as claimed in claim 1, wherein said first Universal joint (5) is fixedly mounted on input side and having sliding joint on output side to take care of manufacturing variation.
8. The assembly as claimed in claim 1, wherein said coupling (10a) is having sliding joint on both end in order to facilitate ease of assembling and dismantling on vehicle with said rack and pinion (11) and isolates road excitation and provides cushioning to accommodate variation in manufacturing for said rack and pinion mounting.
9. The assembly as claimed in claim 1, wherein said true angles "a,b,c,d" subtended by two adjacent shaft ranges from 35 to 45 degrees and said universal joints operates from 0 to 60 degrees of true intended angle.
10. A steering column assembly substantially as herein described with reference to the accompanying drawings.