FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION
"Preload Adjustment Mechanism For Front Fork Of A Vehicle"
2. APPLICANT
(a) NAME : GABRIEL INDIA LIMITED
(b) NATIONALITY: An Indian Company registered under the provisions of
The Companies Act, 1956
(c) ADDRESS : 29th, Milestone, Pune Nasik Highway,
Village-. Kutuli, Tal Khed, Dist:Pune-410 501 (MH)
3. PREAMBLE TO THE DESCRIPTION
COMPLETE
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 suspension assembly of a vehicle, and more particularly, the present invention relates to a preload adjustment mechanism for front fork of a two-wheeler.
Background of the invention
Preload or preload height is basically spring pre-compression in suspension assembly. Specifically, the preload is the distance to which the spring is compressed from its free length as it's installed in the front fork assembly in fully extended condition. The preload in the front fork is an important comfort parameter and is achieved by a component called spacer. The spacer is a thin walled steel tube, the length of which decides the factor of spring pre-compression, which in turn decides spring pre-load.
In the conventional suspension assembly of the two-wheeler, the spring is introduced inside the inner tube, followed by a washer and a spacer of specific, length. The entire assembly of the spring, washer and spacer protrudes outside the inner tube. When a bolt cap is screwed against the inner tube, the bolt cap compresses the spring generating required pre-compression. As all other part, such as spring and washer are tooled up and standard, only spacer length is varied from model to model to create different pre-compression.
Drawback of the prior art
1. In the conventional suspension assembly, the preload for a particular fork is fixed and cannot be altered externally, once the suspension assembly is assembled.

2. In the conventional suspension assembly, to change the preload of me front fork; one has to partially dismantle the bike, open the front fork, replace the spacer with a new length, which is a cumbersome process, and requires huge time.
3. In conventional suspension assembly having regular forks, person having less weight, the preload may appear to hard for riders having less weight and the preload may appear to soft and mushy for riders having more weight.
Accordingly, there exist a need to provide a front fork suspension assembly for the two-wheeler which overcomes drawbacks of the prior art.
Objects of the invention
An object of the present invention is to provide preload adjustment externally for front fork of the two-wheeler, for providing the end user option to set pre-compression based on his ride feeling.
Another object of the present invention is to facilitate flexibility in the existing of front fork design with miniscule disparity in cost.
Yet another object of the present invention is to provide preload adjustment mechanism for the two-wheeler wherein other parameters for the front fork do not get affected.
Summary of the invention
Accordingly, the present invention provides a preload adjustment mechanism for front fork of a vehicle, the mechanism comprising:

an adjuster means having a cam profile on one end thereof, the cam profile having a plurality of cam positions, wherein each cam position of the plurality of cam positions defines a predefined preload level;
a plunger rod having a protrusion on a side wall thereof, the plunger, rod being mounted within the adjuster means, wherein the plunger rod compresses a spring of the front fork to a predefined length depending upon a cam position of the plurality of cam positions in which the protrusion of the plunger rod is being resteil; and
a bolt cap for holding the plunger rod against linear as well as rotational pressure, the bolt cap having a slot corresponding to the protrusion of the plunger rod,
wherein upon giving rotational motion to the plunger rod, the protrusion of the plunger rod slides over at least one cam position of the plurality of cam positions thereby achieving a predefined preload level.
Brief description of the drawings
Figure 1 shows an exploded view of a preload adjustment mechanism for front'fork of a two-wheeler, in accordance with the present invention;
Figure 2 shows an assembled view of a preload adjustment mechanism for front fork of a two-wheeler in maximum preload position, in accordance with the present invention; and
Figure 3 shows an assembled view of the preload adjustment mechanism for front fork of a two-wheeler in minimum preload position, in accordance with the present invention.

Detailed description of the drawings
The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the preferred embodiment.
The present invention provides a preload adjustment mechanism for front fork of a two-wheeler which allows preload adjustment externally in discrete steps, for providing end user to set pre-compression based on his ride feeling. Further, the preload adjustment mechanism facilitates flexibility in the existing design with miniscule disparity in cost. Furthermore, the preload adjustment mechanism do not affect other parameters of the existing the front fork. The preload may be adjusted based on the rider's weight and comfort feeling.
Referring now to figure 1, 2 and 3, there is shown a preload adjustment mechanism to vary the preload externally, for front fork of a two-wheeler, in accordance with the present invention. Specifically, the figure 1 shows the preload adjustment mechanism (100) (hereinafter the 'mechanism (100)). The mechanism (100) includes an adjuster means (10), a plunger rod (20), and a bolt cap (30).
The adjuster means (10) includes a cam profile (12) on one end thereof. The cam: profile (12) further includes a plurality of cam positions (not numbered) thereon. Specifically, each cam position of the plurality of cam positions defines a predefined preload level. Further, the adjuster means (10) includes a protuberance (14) thereon.
The plunger rod (20) is mounted within the adjuster means (10). The plunger rod (20) includes a protrusion (22) on a side wall thereof. The plunger rod, (20)

compresses a spring of the front fork to a predefined length depending upon a canr position of the plurality of cam positions on which the protrusion (22) of the plunger rod (20) is being rested upon rotation of the plunger rod (20) For the purpose of explanation, only the mechanism (100) is shown without the entire front fork assembly and working thereof. The plunger rod includes a first 'o' ring (24) on thereon for sealing oil leak between the plunger rod (20) and the bolt cap (30)
The bolt cap (30) holds the plunger rod (20) against linear as well as rotational pressure. The bolt cap (30) includes a slot (32) configured thereon corresponding to the protuberance (14) of the adjuster means (10). The engagement of the protuberance (14) in the slot (32) provides locking thereof and arrests motion of the adjuster means (10) along with the plunger rod (20). With the arrangement of the protuberance (14) with the slot (32), the adjuster means (20) undergoes in-slidiiig motion which induces a varying pre-compression in the spring, which further lead§
to pre-load. However, it may be evident to those skilled in the art that instead of
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protuberance (14) and the slot (32), any other suitable locking mechanism (may be used to arrest the motion of the adjuster means (10) along with the plunger rod (20). The bolt cap (30) includes second 'o' ring (34) thereon for sealing oil leak between the bolt cap and an inner tube (not shown).
When a rotational motion is given to the plunger rod (20), the protrusion,(22) of the plunger rod slides over a cam profile (12) of the adjuster means (10) thereby varying the pre-compression as per the comfort of the rider. The cam prqfile(l2) has various cam positions which correspond to different preload levels. Specifically; each level of the cam position corresponds to an increase of pre-compression. The preset pre-compression can be achieved by a regular spacer. The plunger rod, (20} can be rotated further by using any standard tool, for example, a spanner. However

it may evident to those skilled in the art to use any other rotating tool know in;'tile art, such as a knob.
The plunger rod (20) is held fixed by the bolt cap (30) against linear as well as rotational pressure as the plunger rod (20) slides over the cam profile (I2) of ;the adjuster means (10). The plunger rod (20) compresses a spring of the front fork (not shown) depending upon the cam height on which the protrusion (22) thereof is rested.
For example, each level of the cam position corresponds to an increase of pre-compression as shown below:
Step 1: X+0 Step2: X+5mm Step3: X+12mm , and the
like.
Wherein X stands for preset pre-compression which can be achieved by a regular spacer.
The preload adjuster mechanism (100) allows a variation of predetermined length, for example, 12 mm for 033 front fork and variation may go up to 25, mm for higher diameter front forks.
Referring now to figure 2, there is shown an assembled view of the preload adjustment mechanism (100) for front fork of the two-wheeler in a maximum preload position, in accordance with the present invention. Specifically, the plunger rod (20) is rotated by means of the spanner in such a way that the protrusion (22) of the plunger rod (20) is rested at a upper cam position of the cam profile (12), thereby achieving maximum preload position.

Referring now to figure 3, there is shown an assembled view of the preload adjustment mechanism (100) for front fork of a two-wheeler in a minimum preload position, in accordance with the present invention. Specifically, the plunger rod (20) is rotated by means of the spanner in such a way that the protrusion (22) of the plunger rod (20) is rested at a lower cam position of the cam profile (12), thereby achieving minimum preload position.
The preload adjustment mechanism (100) for front fork of a two-wheeler of the present invention provides for the rider to comfortably change the preload position from hard to soft based on his requirements. A total external pre-compressiori change of predefined length can be achieved through the design of the present invention.
Advantages of the invention:
1. The preload adjustment mechanism (100) of the present invention provides;a
mechanism for preload adjustment which is flexible enough to accommodate in any
front fork up from 033.
2. The preload adjustment mechanism (100) provides additional flexibilitly for end users by providing external control of spring preload.
3. The preload adjustment mechanism (100) provides discrete stages, as feasible and desired for preload adjustment which are better than variable preload available worldwide as the present invention gives users definitive information about current preload.

4. The preload adjustment mechanism (100) allows lert ana right tront tork balance to be done easily as compared to continuous control where the end user has to be aware of pre-compression level, on each fork and balance it with other.
5. Preload adjustment mechanism of the present invention adds high value to existing product with little increase in cost.
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended-to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the spirit or scope of the present invention.

We Claim:
1. A preload adjustment mechanism for front fork of a vehicle, the
mechanism comprising:
an adjuster means having a cam profile on one end thereof, the earn protile having a plurality of cam positions, wherein each cam position of the plurality of cam positions defines a predefined preload level;
a plunger rod having a protrusion on a side wall thereof, the plunger rod being mounted within the adjuster means, wherein the plunger rod compresses a spring of the front fork to a predefined length depending upon a cam position of the plurality of cam positions in which the protrusion of the plunger rod is being rested; and
a bolt cap for holding the plunger rod against linear and rotational pressure, the bolt cap having a slot configured thereon,
wherein upon giving rotational motion to the plunger rod, the protrusion.of the plunger rod slides over at least one cam position of the plurality of cam positions thereby achieving a predefined preload level.
2. The preload adjustment mechanism for front fork as claimed in,claim -, wherein the adjuster means further comprises a protuberance thereon corresponding to the slot of the bolt cap.
3. The preload adjustment mechanism for front fork as claimed in:claim ilf wherein the preset pre-compression is achieved by a regular spacer.

4.. The preload adjustment mechanism for front fork as claimed in claim 1, wherein the plunger rod is rotated by using a spanner.