FORM 2
THE PATENT ACT 1970 (as amended)
[39 OF 1970]
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
[See Section 10 and Rule 13]
TITLE: “A MACPHERSON STRUT ASSEMBLY WITH VARYING RIDE HEIGHTAND METHODS THEREOF”
NAME AND ADDRESS OF THE 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.
Nationality: INDIAN
The following specification particularly describes the nature of the invention and the manner in which it is to be performed.

TECHNICAL FIELD
The disclosure relates to a MacPherson strut structure, more particularly relates to MacPherson strut assembly with varying ride height of a vehicle.
BACKGROUND OF DISCLOSURE AND PRIOR ARTS
Ride height for a vehicle is defined as the distance between wheel center to wheel arc. A higher ride height means, the center of mass of the vehicle is higher. Higher ride height also gives better ground clearance. However, lower ride height gives the vehicle a better handling stability, but it deteriorates the rough road capability of the vehicle.
Existing, one way to vary ride height is made by mounting a rubber bellow on the MacPherson strut. The rubber bellows are filled with air to adjust the ride height. However, the said method of adjusting ride height with rubber bellow is totally a different concept. The method doesn’t work on a coil spring to achieve desired spring stiffness. The stiffness is obtained by compression of air in the bellows.
Another existing way to change the ride height is made by changing resting position of bottom side of the spring. The spring sits on two different positions of the bottom resting plate mounted over the strut cylinder. The positions of the bottom plate are based on two different coil diameters for the spring. Firstly, in springing position/normal position, the helical spring is supported with the resting plate surface of smaller diameter. In the second springing position/sport position, the helical spring is supported with resting plate surface of larger diameter. However, the said method of varying height has a limitation, wherein all types of helical springs cannot be accommodated. Only springs with different coil diameters are used. The springs with same coil diameter/cylindrical helical spring cannot be accommodated as the end coil turn diameters are same and doesn’t allow the spring to rest on an inner spring seat. In addition, welding of two different resting plates to the strut cylinder is critical and not feasible. A movement of inner resting plates (upward or downward) is made with the threading provided on strut cylinder, which makes the strut structure more complex. The FIG. 1 illustrates an existing MacPherson strut assembly.

OBJECTS OF THE DISCLOSURE
The object of disclosure is to adjust the ride height for sporty feel on the vehicle (car) and the requirement of higher ground clearance by moving the spring upward based on the customer requirement.
The object of the disclosure is to accommodate any type of helical spring (spring with same coil diameter or different diameter) in the Macpherson strut assembly.
The object of the disclosure is to provide a method of varying ride height of the MacPherson strut assembly.
STATEMENT OF THE DISCLOSURE
Accordingly, the disclosure provides for a Macpherson strut assembly (1) with variable ride height, said assembly comprising a piston rod (2) consisting a plurality of stepped portions of various diameters; a coil spring (4) mounted on the piston rod (2) and in between a upper spring seat (5a) and a lower spring seat (5b) of the strut assembly; a strut bearing (3) mounted on one of the stepped portion of the piston rod (2) and below the upper spring seat (5a) to obtain the variable ride height of the Macpherson strut assembly (1), also provides for a method of varying ride height of a Macpherson strut assembly (1), said method comprising acts of mounting a coil spring (4) on to a piston rod (2) consisting of a plurality of stepped portions of various diameter on its surface; mounting a strut bearing (3) on one of the stepped portion of the piston rod (2) to vary the ride height; and also provides for a method of assembling a Macpherson strut assembly (1) with variable ride height, said method comprising acts of a piston rod (2) configured to have plurality of stepped portions of various diameter on its surface; an upper spring seat (5a) and a lower spring seat (5b) mounted onto the piston rod (2); a coil spring (4) mounted in between the upper spring seat (5a) and lower spring seat (5b) and around the piston rod (2); a strut bearing (3) mounted on at least one of the stepped portion of the piston rod (2).

SUMMARY
In one embodiment of the disclosure, a Macpherson strut assembly (1) with variable ride height, said assembly comprising a piston rod (2) consisting a plurality of stepped portions of various diameters; a coil spring (4) mounted on the piston rod (2) and in between a upper spring seat (5a) and a lower spring seat (5b) of the strut assembly; a strut bearing (3) mounted on one of the stepped portion of the piston rod (2) and below the upper spring seat (5a) to obtain the variable ride height of the Macpherson strut assembly (1).
In one embodiment, the piston rod (2) consists of three stepped portions (2a, 2b and 2c) with increased diameter from an end connecting to a vehicle tower.
In one embodiment, any one of sleeve (6b, 6c) corresponding to the stepped portion (2b, 2c) is mounted in between the strut bearing (3b, 3c) and the vehicle tower.
In one embodiment, a method of varying ride height of a Macpherson strut assembly (1), said method comprising acts of mounting a coil spring (4) on to a piston rod (2) consisting of a plurality of stepped portions of various diameter on its surface; mounting a strut bearing (3) on one of the stepped portion of the piston rod (2) to vary the ride height;
In one embodiment, a method of assembling a Macpherson strut assembly (1) with variable ride height, said method comprising acts of a piston rod (2) configured to have plurality of stepped portions of various diameter on its surface; an upper spring seat (5a) and a lower spring seat (5b) mounted onto the piston rod (2); a coil spring (4) mounted in between the upper spring seat (5a) and lower spring seat (5b) and around the piston rod (2); a strut bearing (3) mounted on at least one of the stepped portion of the piston rod (2).
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The novel features and characteristic of the disclosure are set forth in the appended claims. 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 shows MacPherson strut assembly according to prior art.
FIGS. 2a to 2c shows strut bearing arrangement at various positions on the piston rod of the MacPherson assembly according to the disclosure.
FIG. 3 shows Macpherson strut assembly with lowest ride height according to the disclosure.
FIG. 4 shows Macpherson strut assembly with highest ride height according to the disclosure.
FIG. 5 shows Macpherson strut assembly with nominal ride height according to the disclosure.
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
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, and figures 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.
FIG. 2a, FIG. 2b and FIG. 2c illustrates strut bearing arrangement at various positions on the piston rod of the MacPherson assembly (1). The MacPherson strut assembly is basically vertical structure mounted to a wheel knuckle at the bottom of the vehicle and to a vehicle tower at the top. The change or varying of ride height is achieved by changing assembly length of the MacPherson strut assembly (1). The length of the Macpherson strut assembly (1) is varied for changing the ride height for sporty feel on the vehicle/car and the requirement of higher ground clearance by moving the spring upward or downward based on the requirement. The MacPherson strut assembly length is changed by positioning a strut bearing (3) at different place on the piston rod (2) against which helical/coil spring (4) and upper spring seat (5a) rests (shown in FIGS 3-5). The piston rod (2) of the MacPherson assembly (1) is configured into three stepped portions (2a, 2b and 2c) for varying the ride height. The said stepped portions (2a, 2b and 2c) are of three different diameters on the strut piston rod. A strut bearing (3a, 3b and 3c) sits onto corresponding stepped portion (2a, 2b and 2c) of the piston rod (2) along with an upper spring seat (5a) for varying the ride height.
The ride height is maximum (Position-A) when the strut bearing (3a) sits on the top most stepped portion (2a). The ride height is minimum (Position-C) when the strut bearing (3c) sits on the lower most stepped portion (2c). The upper spring seat (5a) (where the upper portion of the coil spring rest) along with coil spring (4) move upwards or downwards and rests against the strut bearing (3). Any type of helical/coil spring is used in the disclosed MacPherson assembly and hence, the assembly is feasible for manufacturing mass production.
Three different strut bearing (3a, 3b and 3b) with different inner diameters are used to match diameter of stepped portions (2a, 2b and 2c) of the piston rod (2). The diameter of stepped portion (2a) matches with inner diameter of the strut bearing (3a). The diameter of stepped portion (2b) matches with inner diameter of the strut bearing (2b). The

diameter of stepped portion (2c) matches with inner diameter of the strut bearing (3c). Length of the stepped portions (2a, 2b and 2c) is about 25 mm each.
FIG. 3 illustrates the Macpherson strut assembly (1) with lowest ride height according to the disclosure. The strut bearing (2c) is in the Position-C. The lowest ride height is achieved by assembling the piston rod (2) along with coil spring (4) and the upper spring seat (5a) at the stepped portion (2c) on the piston rod using the strut bearing (3c). A sleeve (6c) is mounted above the strut bearing (3c) and onto the stepped portion (2c). Since the stepped portions (2b, 2c) creates a gap in between the strut bearing (2c) and the vehicle tower, the sleeve (6c) provides the supporting structure in between the vehicle tower and the strut bearing (3c).
FIG. 4 illustrates Macpherson strut assembly (1) with highest ride height according to the disclosure. The strut bearing (2a) is in the Position-A. The highest ride height is achieved by assembling the piston rod (2) along with coil spring (4) and the upper spring seat (5a) at the stepped portion (2a) on the piston rod (2) using the strut bearing (3a). Here there is no sleeve provided as the strut bearing (3a) directly contacts the vehicle tower.
FIG. 5 illustrates Macpherson strut assembly (1) with nominal ride height according to the disclosure. The strut bearing (2b) is in the Position-B. The nominal ride height is achieved by assembling the piston rod (2) along with a coil spring (4) and the upper spring seat (5a) at the stepped portion on the piston rod (2) using the strut bearing (3b). A sleeve (6b) is mounted above the strut bearing (3b) and onto the stepped portion (2b). Since the stepped portions (2b, 2c) creates a gap in between the strut bearing (2b) and the vehicle tower, the sleeve (6b) provides the supporting structure in between the vehicle tower and the strut bearing (3b).
Advantages
In one embodiment, the MacPherson strut assembly accommodates any type of helical spring (spring with same coil diameter or different diameter) into it and is the arrangement is feasible for manufacturing mass production.

In one embodiment, there is no extra spring rest plate welding is required and no threading needs to be provided on strut cylinder for inner rest plate movement.
In one embodiment, assembling and disassembling of peripheral parts of the MacPherson strut assembly is easy.
In one embodiment, since the Macpherson strut assembly uses the same piston for varying the ride heights, the manufacturing cost is less and economical.
In one embodiment, the maximum ride heights of the Macpherson strut assembly in the vehicles provides increased ride comfort.
In one embodiment, the minimum ride heights of the Macpherson strut assembly in the vehicles provides increased ride comfort during long journeys/rides.
Referral numerals:
1: MacPherson strut assembly
2: Piston rod
2a: Stepped portion at vehicle tower end
2b: Stepped portion below the stepped portion 2a
2c: Stepped portion below the stepped portion 2b
3: Strut bearing
3a: Strut bearing mounted onto stepped portion 2a
3b: Strut bearing mounted onto stepped portion 2b
3c: Strut bearing mounted onto stepped portion 2c
4: Coil/helical spring
5a: Upper spring seat at vehicle tower end
5b: Lower spring seat at vehicle knuckle end
6b: Sleeve mounted onto the strut bearing 3b
6c: Sleeve mounted onto the strut bearing 3c

Equivalents
With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C

together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B."
While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

We claim:
1. A Macpherson strut assembly (1) with variable ride height, said assembly comprising:
a piston rod (2) consisting a plurality of stepped portions of various diameters;
a coil spring (4) mounted on the piston rod (2) and in between a upper spring seat (5a) and a lower spring seat (5b) of the strut assembly;
a strut bearing (3) mounted on one of the stepped portion of the piston rod (2) and below the upper spring seat (5a) to obtain the variable ride height of the Macpherson strut assembly (1).
2. The Macpherson strut assembly as claimed in claim 1, wherein said piston rod (2) consists of three stepped portions (2a, 2b and 2c) with increased diameter from an end connecting to a vehicle tower.
3. The Macpherson strut assembly as claimed in preceding claims, wherein any one of sleeve (6b, 6c) corresponding to the stepped portion (2b, 2c) is mounted in between the strut bearing (3b, 3c) and the vehicle tower.
4. A method of varying ride height of a Macpherson strut assembly (1), said method comprising acts of:
mounting a coil spring (4) on to a piston rod (2) consisting of a plurality of stepped portions of various diameter on its surface;
mounting a strut bearing (3) on one of the stepped portion of the piston rod (2) to vary the ride height;
5. The method as claimed in claim 4, wherein any one of sleeve (6b, 6c) corresponding to the stepped portion (2b, 2c) is mounted in between the strut bearing (3b, 3c) and a vehicle tower.
6. A method of assembling a Macpherson strut assembly (1) with variable ride height, said method comprising acts of:
a piston rod (2) configured to have plurality of stepped portions of various diameter on its surface;

an upper spring seat (5a) and a lower spring seat (5b) mounted onto the piston rod (2);
a coil spring (4) mounted in between the upper spring seat (5a) and lower spring seat (5b) and around the piston rod (2);
a strut bearing (3) mounted on at least one of the stepped portion of the piston rod (2).
7. The method as claimed in claim 6, wherein any one of sleeve (6b, 6c) corresponding to the stepped portion (2b, 2c) is mounted in between the strut bearing (3b, 3c) and a vehicle tower.
8. A Macpherson strut assembly, a method of varying ride height of Macpherson strut assembly and a method of assembling are substantially as herein above described and as illustrated in accompanying drawings.