FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION Wheel Aligning Twist Beam
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
INVENTOR
Santosh Kumar Singh
An 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 particularly describes the invention and the manner in which it is to be performed.

FIELD OF INVENTION
The present invention is related to suspension system of vehicle and more particularly to a wheel alignment mechanism by which toe and camber on a twist beam can be adjusted.
BACKGROUND OF THE INVENTION
There are many types of rear suspension used in the vehicle categorized into rigid axle suspension, semi independent and independent suspension. The purpose of the suspension is to support the vehicle, provide good ride and handling. The wheel geometry is one of the parameter which affects the handling of the vehicle. Wheel geometry apart from influencing the vehicle handling also affects the tyre life. There are means of adjusting the wheel geometry angles i.e. camber and toe on independent suspension viz. McPherson suspension, multilink suspension etc. but the camber and toe angles on independent and semi-independent suspension are not adjustable.
US 5,301,977 describes a system for providing toe and camber adjustment for a normally fixed wheel of a vehicle using a plate member, in conjunction with portions of the structure of the suspension system of the vehicle, to locate at least one center point for the formation of new aligned openings so that a portion of the control system may be moved from an original location and secured at a new location to provide for the toe and camber adjustment.
In case of twist beam suspension which is semi independent suspension the toe and camber angles are produced by machining wheel mounting bracket which is welded to the trailing arm. The toe and camber angles once machined on the twist beam cannot be adjusted on the vehicle. There are certain difficulties associated with the twist beam manufacturing due to the precise and expensive machining operation. Each twist beam has to be inspected for the correctness of the toe and camber

values machined onto it. This inspection requires expensive wheel geometry measurement fixtures. Also the cost of inspection is high. Furthermore if any twist beam is out of specification at part level, it cannot be rectified and has to be scrapped. This results in heavy rejection cost. Also the camber and toe value of the twist beam at part level and vehicle level are different due to the loading of the vehicle on the twist beam and the tolerance stack up of the assembly. Many times it happens that though the camber and toe angles on the twist beam at the part level are correct, they are out of specification on the vehicle. Even in this case the twist beam has to be rejected and call for the rejection cost. There are cases when the twist beam gets damaged or bent during the vehicle running. This causes change in the wheel geometry and as a consequence the handling deteriorates and tyre wearing starts. Since the geometry cannot be adjusted on the twist beam, it has to be replaced with the new one.
OBJECTS OF INVENTION
The main object of the present invention is to obviate the above mentioned drawbacks by providing toe and camber adjustment on the twist beam.
Another object of the present invention is to provide a method of adjustment of rear suspension wheel geometry of a vehicle having twist beam.
Another object of the present invention is to eliminate the precise, controlled and costly machining process of producing combined toe and camber angles on the twist beam.
Another object of the present invention is to eliminate the toe and camber measuring machine from the manufacturing line and thereby reducing the time and cost of manufacturing the twist beam.

Yet another object of the invention is to eliminate the rejection of twist beam at the manufacturing line due to incorrect machining of toe and camber angles on the said twist beam.
Yet another object of the invention is to eliminate rejections from manufacturing line of the vehicle, due to non conformance of toe and camber values at the vehicle level.
SUMMARY OF THE INVENTION
In order to achieve the above objects, the present invention discloses a twist beam provided with adjustable toe and camber mechanism on the trailing arm of the twist beam. A base plate is fitted to the trailing arm. A camber plate which is hinged to the base plate provides camber angle adjustment. A fastening means including a suitable fastener and a washer nut is used to connect the camber plate and the base plate. Preferably the fastener used is bolt known as camber bolt. The washer nut is tightened over the camber bolt which butts over the inner surface of the base plate. The loosening and tightening of the washer nut over the camber bolt adjusts the camber angle to the desired value.
A toe plate hinged to the camber plate provides toe angle adjustment. A fastening means including a suitable fastener and a washer nut is used to connect the toe plate and the base plate. Preferably the fastener used is bolt known as a toe bolt. A washer nut is tightened over the toe bolt which butts over the inner surface of the base plate. The loosening and tightening of the washer nut over the toe bolt adjusts the toe angle to the desired value.
STATEMENT OF INVENTION
Accordingly, the invention provides a wheel alignment device comprising a toe and camber adjusting mechanism; said mechanism comprising: a base plate capable of being joined to a trailing arm of a twist beam; a camber plate capable of being

connected to the base plate at one end and fastened with the base plate at a second end using a first fastening means; a toe plate capable of being connected to the camber plate at one end and fastened with the base plate at a second end using a second fastening means; said first and/or second fastening means capable of being tightened or loosened to independently adjust camber and/or toe angle of the wheel.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring now to the drawings where in the showings are for the purpose of illustrating a preferred of limiting the same,
Figure 1 shows the twist beam with toe and camber adjusting mechanism as viewed from outer side of vehicle
Figure 2 shows the enlarged view of toe and camber adjusting mechanism as viewed from outer side of vehicle
Figure 3 shows the twist beam with toe and camber adjusting mechanism as viewed from inner side of vehicle
Figure 4 shows the construction of the base plate according to this invention
Figure 5 shows the construction of the camber plate according to this invention
Figure 6 shows the construction of the toe plate according to this 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 structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION OF THE INVENTION
In the following detailed description, reference is made to the accompanying figures, which form a part hereof. In the figures, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, figures, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and make part of this disclosure.
The current invention relates to a wheel alignment device comprising a toe and camber adjusting mechanism which is capable of being joined to a trailing arm (2) of a twist beam (1) on one or both sides of the vehicle as shown in fig. 1. Preferably the joining of said adjusting mechanism and trailing arm is by the way of bolting or welding or the like.
Figures 2 & 3 show the enlarged view of toe and camber adjusting mechanism. A base plate (3) is configured to be joined to the trailing arm (2) of the twist beam (1). A camber plate (7) is provided to be connected to the base plate (3) and a toe plate (11) is provided to be connected to the camber plate (7) and the base plate (3). The means of connection will be explained later in the specification.
Figure 4 shows construction of the base plate (3). The base plate can be made of casting or sheet metal. The base plate has at least two hollow cylindrical members (4) at its bottom surface which are at a certain distance apart from each other. The base plate has at least two recesses (5, 6) to facilitate fastening of the camber plate (7) and toe plate (11) to the base plate.

Figure 5 shows the construction of the camber plate (7). The camber plate has at least two hollow cylindrical members (8, 9). A first hollow cylindrical member (8) is provided to be mountable between the at least two hollow cylindrical members (4) of the base plate and a second hollow cylindrical member (9) is provided to be mountable between the hollow cylindrical members (12 of fig. 6) of the toe plate (11of Fig.6).
Figure 6 shows construction of toe plate (11). The toe plate has at least two hollow cylindrical members (12) between which the second hollow cylindrical member (9) of the camber plate (7) is mountable. The toe plate (11) also has a recess (14) for fastening it to the base plate (3). A plurality of recesses (13) is provided on the surface of the toe plate. These recesses (13) in the toe plate (11) are provided for the mounting of the wheel assembly. The wheel assembly comprises of bearing, brake plate, brake drum wheel rim and the tyre. The bearing is mounted on the toe plate (11) through appropriate fastening means. The brake plate is sandwiched between bearing and the toe plate (11). The brake drum is mounted over the bearing and the tyre is mounted over the brake drum.
As shown in fig 2, the camber plate (7) is connected to the base plate (3) at one end (50) and fastened with the base plate at a second end (53) using a first fastening means (Fl). The toe plate (11) is connected to the camber plate (7) at one end (52) and fastened with the base plate (3) at a second end (51) using a second fastening means (F2). The first and/or second fastening means (Fl, F2) capable of being tightened or loosened to independently adjust camber and/or toe angle of the wheel.
The first fastening means (F1) according to an embodiment of this invention is a bolt (15) and washer nut (16) arrangement. However one can envisage a fastening means that would include other fasteners that would achieve the same functionality. The first fastening means (Fl) comprises a first fastener element (15) passing through recesses (5, 10) in the base plate (3) and the camber plate (7). The washer nut (16) arrangement is used to tighten or loosen the first fastener element (15) over

the inner surface of the base plate (3). Loosening and tightening of the washer nut (16) over the bolt (15) adjusts the camber angle to the desired value to provide for wheel alignment.
The second fastening means (F2) according to an embodiment of this invention is bolt (21) and washer nut (22) arrangement. However one can envisage fastening means include other fasteners that would achieve the same function. The second fastening means (F2) comprises a second fastener element (21) passing through recesses (6, 14) in the base plate (3) and toe plate (11). The washer nut arrangement (22) is used to tighten or loosen the second fastener element (21) over the inner surface of the base plate (3). Loosening and tightening of the washer nut (22) over the bolt (21) adjusts the toe angle to the desired value to provide for wheel alignment.
The camber plate (7) is connected to the base plate (3) by a first hinge assembly (H1). The first hinge assembly (H1) is formed by inserting first elongate member (19) through the hollow cylindrical members (4) of the base plate and the first hollow cylindrical member (8) of the camber plate in such a way that this assembly acts as a hinge as shown in fig. 2. The first elongate member (19) according to the embodiment of this invention is pin (19). A first fastening member (20) is provided at an end of the elongate member (19) protruding outside from one end (30) of the hollow cylindrical member (4) of the base plate. The first fastening member (20) according to the embodiment of this invention is a nut (20). The nut (20) is tightened over the pin (19) after the camber adjustment is done to provide rigidity to the said assembly.
The toe plate (11) is connected to the camber plate (7) by a second hinge assembly (H2). The second hinge assembly (H2) is formed by inserting a second elongate member (17) through the hollow cylindrical members (12) of the toe plate and the second hollow cylindrical member (9) of the camber plate in such a way that this assembly acts as a hinge as shown in fig. 2. The second elongate member (17)

according to the embodiment of this invention is a pin (17). A second fastening member (18) is provided at an end of the second elongate member (17) protruding outside from one end (31) of the hollow cylindrical member (12) of the toe plate. The second fastening member (18) according to the embodiment of this invention is a nut (18). The nut (18) is tightened over the pin (17) after the toe adjustment is done to provide rigidity to the said assembly.
The wheel alignment is done on the assembly line of the vehicle at the wheel alignment station. The Design value of the toe and the camber is provided by the OEM (Original Equipment Manufacturer). During the wheel alignment of the vehicle, if the toe and camber values are not within the specifications then each of the angle i.e toe angle and the camber angle for each of the wheel can be independently adjusted. Camber can be adjusted by the rotation of the fastening mechanism (F1). F1 is not only the fastening mechanism but it has the dual purpose i.e fastening as well as the camber adjustment through Hinge (H1). Similarly, toe can be adjusted by the rotation of the fastening mechanism (F2). F2 is not only the fastening mechanism but it has the dual purpose i.e fastening as well as the toe adjustment through Hinge (H2)
In the aforementioned manner both the toe and camber angle can be adjusted by providing the additional attachments and adjustment means. The present invention provides a mechanism to adjust the camber and toe angles on the twist beam at any time i.e. at the time of production and at the time of maintenance. This reduces the cost of complex machining and the necessity of 100% inspection at the supplier end thereby reducing the manufacturing cost, inspection cost and the cost of measurement and inspection fixture. The wheel geometry now can thus be directly adjusted to the desired specification on the vehicle assembly line and avoid twist beam rejections at the assembly line. This invention also helps to reduce the requirement of replacement of parts after long use of vehicles due to change in camber and toe angle.

WE CLAIM
1. A wheel alignment device comprising:
a toe and camber adjusting mechanism; said mechanism comprising
a base plate (3) capable of being joined to a trailing arm (2) of a twist beam(l);
a camber plate (7) capable of being connected to the base plate (3) at one end and fastened with the base plate at a second end using a first fastening means (F1);
a toe plate (11) capable of being connected to the camber plate (7) at one end and fastened with the base plate (3) at a second end using a second fastening means (F2);
said first and/or second fastening means (F1, F2) capable of being tightened or loosened to independently adjust camber and/or toe angle of the wheel.
2. The wheel alignment device as claimed in claim 1, wherein said first fastening means (Fl) comprises a first fastener element (15) passing through recesses (5, 10) in the base plate (3) and the camber plate (7) and a washer nut arrangement (16) to tighten or loosen the first fastener element (15) over the inner surface of the base plate (3).
3. The wheel alignment device as claimed in claim 1, wherein said second fastening means (F2) comprises a second fastener element (21) passing through recesses (6, 14) in the base plate (3) and the toe plate (11) and a washer nut arrangement (22) to tighten or loosen the second fastener element (21) over the inner surface of the base plate (3).
4. The wheel alignment device as claimed in claim 1, wherein the base plate (3) and the toe plate (11) each has at least two hollow cylindrical members spaced apart from each other.

5. The wheel alignment device as claimed in claim 4, wherein the camber plate (7) has a first hollow cylindrical member (8) mountable between the hollow cylindrical members (4) of the base plate and a second hollow cylindrical member (9) mountable between the hollow cylindrical members (12) of the toe plate (11).
6. The wheel alignment device as claimed in claim 5, wherein a first elongate member (19) is inserted through the hollow cylindrical members (4) of the base plate and the first hollow cylindrical member (8) of the camber plate to form a first hinge assembly (H1).
7. The wheel alignment device as claimed in claim 6, wherein a fastening member (20) is provided at an end of the elongate member (19) protruding outside from one end (30) of the hollow cylindrical member (4) of the base plate.
8. The wheel alignment device as claimed in claim 5, wherein a second elongate member (17) is inserted through the hollow cylindrical members (12) of the toe plate and the second hollow cylindrical member (9) of the camber plate to form a second hinge assembly (H2).
9. The wheel alignment device as claimed in claim 8, wherein a fastening member (18) is provided at an end of the second elongate member (17) protruding outside from one end (31) of the hollow cylindrical members (12) of the toe plate.