Claims:We Claim:

1. A preload adjuster (100) for front fork suspension of a two wheeled motor vehicle comprising of a top cap (1), a gear (5), an adjuster screw (10) with teeth (10b), an O-ring (15), a fork bolt (20), an O-ring (25), a lock nut (30), a sliding nut (35), a supporting piece (37), a restricting disk (40), a locking screw (45), a spacer tube (50), a washer (60), and a main spring (65); wherein,
- the gear (5) is mounted below the top cap (1) on the fork bolt (20) such that its mounting is offset with the central axis of the adjuster screw (10) making the teeth (10b) of the adjuster screw (10) is in mesh with an internal teeth (5b) of the gear (5) at every rotational cycle of the adjuster screw (10);
- the top cap (1) has a display window (1a) that is configured to indicate the numerical value marked on a display surface (5a) of the gear (5) identifying each one of its multiple internal gear teeth (5b);
- the O-ring (15) is mounted in a groove given on the adjuster screw (10) along the curved surface in contact with the fork bolt (20);
- the O-ring (25) is mounted in a groove given on the fork bolt (20) along the curved surface in contact with an inner tube (55) of the front fork;
- the lock nut (30) is mounted in the fork bolt (20) on the threads given on the surface (10Q) of the adjuster screw (10) such that the upper surface of the lock nut (30) rests on the lowest step on the adjuster screw (10);
- the sliding nut (35) is mounted below the locking nut (30) on the threads given on the surface (10Q) of the adjuster screw (10) and has one flat surface (35f) that rotationally locks the sliding nut (35) with an inside surface (20f) of the fork bolt (20) such that when the adjuster screw (10) is rotated, the sliding nut (35) remains free only to move linearly along the surface (10Q) of the adjuster screw (10);
- the supporting piece (37) is positioned below the sliding nut (35) on the adjuster screw (10) and has one surface that is supported on a lower surface of the sliding nut (35);
- the restricting disk (40) is mounted below the adjuster screw (10) and is held in its position on the adjuster screw (10) by the locking screw (45) and the locking disc (40); and
- the spacer tube (50) located between the lower surface of the supporting piece (37) and a washer (60) and said washer (60) in communication with the main spring (65) for preload adjustment.

2. A preload adjuster (105) for front fork suspension of a two wheeled motor vehicle comprising of a top cap (1), a gear (5), an adjuster screw (11) with a ring (11B), an O-ring (15), a fork bolt (20), an O-ring (25), a lock nut (30), a sliding nut (35), a supporting piece (37), a restricting disk (40), a locking screw (45), a spacer tube (50), a washer (60), and a main spring (65); wherein,
- the adjuster screw (11) has an ring (11B) screwed on its top using a screw (11A) and said ring (11B) has an internal projection (11BP) that locks with a recess (11R) given at the top of the adjuster screw (11) to prevent its rotation with respect to the adjuster screw (11);
- the gear (5) is mounted below the top cap (1) on the fork bolt (20) such that a teeth (10b) of the ring (11B) is in mesh with at least one internal teeth (5b) of the gear (5) at every rotational cycle of the adjuster screw (11);
- the top cap (1) has a display window (1a) that is configured to indicate the numerical value marked on a display surface (5a) of the gear (5) identifying each one of its multiple teeth (5b);
- the O-ring (15) is mounted in a groove given on the adjuster screw (11) along the curved surface in contact with the fork bolt (20);
- the O-ring (25) is mounted in a groove given on the fork bolt (20) along the curved surface in contact with an inner tube (55) of the front fork;
- the lock nut (30) is mounted in the fork bolt (20) on the threads given on the surface (11Q) of the adjuster screw (11) such that the upper surface of the lock nut (30) rests on the lower step on the adjuster screw (11);
- the sliding nut (35) is mounted below the locking nut (30) on the threads given on the surface (11Q) of the adjuster screw (11) and has one flat surface (35f) that rotationally locks the sliding nut (35) with an inside surface (20f) of the fork bolt (20) such that when the adjuster screw(11) is rotated, the sliding nut (35) remains free only to move linearly along the surface (11Q) of the adjuster screw (11);
- the supporting piece (37) is positioned below the sliding nut (35) on the adjuster screw (11) and has one surface that is supported on a lower surface of the sliding nut (35);
- the restricting disk (40) is mounted below the adjuster screw (11) and is held in its position on the adjuster screw (11) by the locking screw (45) and the locking disc (40); and
- the spacer tube (50) located between the lower surface of the supporting piece (37) and a washer (60) and said washer (60) in communication with the main spring (65) for preload adjustment.

3. A preload adjuster (110) for front fork suspension of a two wheeled motor vehicle comprising of a top cap (1), a gear (6), a screw (6P), an adjuster screw (12) with a ring (11B), an O-ring (15), a fork bolt (21), an O-ring (25), a lock nut (30), a sliding nut (35), a supporting piece (37), a restricting disk (40), a locking screw (45), a spacer tube (50), a washer (60), and a main spring (65); wherein
- the adjuster screw (12) has a ring (11B) screwed on its top using a screw (11A) and the ring (11B) has an internal projection (11BP) that locks with a recess (11R) given at the top of the adjuster screw (12);
- the gear (6) is mounted below the top cap (1) in the support hole (21h) on the fork bolt (21) with the help of the screw (6P) in such way that the central axis of the gear (6) is parallel with the central axis of the screw (12) and teeth (10b) of the ring (11B) is in mesh with at least one external teeth (6b) of the gear (6) at every rotational cycle of the adjuster screw (12);
- the top cap (1) has a display window (1a) that indicates the numerical value marked on a display surface (6a) of the gear (6) identifying each one of its multiple internal gear teeth (6b);
- the O-ring (15) is mounted in a groove given on the adjuster screw (12) along the curved surface in contact with the fork bolt (21);
- the O-ring (25) is mounted in a groove given on the fork bolt (21) along the curved surface in contact with an inner tube (55) of the front fork;
- the lock nut (30) is mounted in the fork bolt (21) on the threads given on the surface (11Q) of the adjuster screw (12) such that the upper surface of the lock nut (30) rests on the lowest step on the adjuster screw (12);
- the sliding nut (35) is mounted below the locking nut (30) on the threads given on the surface (11Q) of the adjuster screw (12) and has one flat surface (35f) that rotationally locks the sliding nut (35) with an inside surface (21f) of the fork bolt (21) such that when the adjuster screw(12) is rotated, the sliding nut (35) remains free only to move linearly along the surface (11Q) of the adjuster screw (12);
- the supporting piece (37) is positioned below the sliding nut (35) on the adjuster screw (12) and has one surface that is supported on a lower surface of the sliding nut (35);
- the restricting disk (40) is mounted below the adjuster screw (12) and is held in its position on the adjuster screw (13) by the locking screw (45) and the locking disc (40); and
- the spacer tube (50) located between the lower surface of the supporting piece (37) and a washer (60) and said washer (60) in communication with the main spring (65) for preload adjustment.

4. A preload adjuster (115) for front fork suspension of a two wheeled motor vehicle comprising of a top cap (1), a gear (6), a screw (6P), an adjuster screw (13) with teeth (10b), an O-ring (15), a fork bolt (21), an O-ring (25), a lock nut (30), a sliding nut (35), a supporting piece (37), a restricting disk (40), a locking screw (45), a spacer tube (50), a washer (60), and a main spring (65); wherein
- the gear (6) is mounted below the top cap (1) in the support hole (21h) on the fork bolt (21) with the help of the screw (6P) in such way that the central axis of the gear (6) is parallel with the central axis of the screw (13) and the teeth (10b) of the adjuster screw (13) is in mesh with at least one external teeth (6b) of the gear (6) at every rotational cycle of the adjuster screw (13);
- the top cap (1) has a display window (1a) that is configured to indicate the numerical value marked on a display surface (5a) of the gear (5) identifying each one of its multiple internal gear teeth (5b);
- the O-ring (15) is mounted in a groove given on the adjuster screw (10) along the curved surface in contact with the fork bolt (21);
- the O-ring (25) is mounted in a groove given on the fork bolt (21) along the curved surface in contact with an inner tube (55) of the front fork;
- the lock nut (30) is mounted in the fork bolt (21) on the threads given on the surface (10Q) of the adjuster screw (10) such that the upper surface of the lock nut (30) rests on the lower step on the adjuster screw (13);
- the sliding nut (35) is mounted below the locking nut (30) on the threads given on the surface (10Q) of the adjuster screw (13) and has one flat surface (35f) that rotationally locks the sliding nut (35) with an inside surface (21f) of the fork bolt (21) such that when the adjuster screw(13) is rotated, the sliding nut (35) remains free only to move linearly along the surface (10Q) of the adjuster screw (13);
- the supporting piece (37) is positioned below the sliding nut (35) on the adjuster screw (13) and has one surface that is supported on a lower surface of the sliding nut (35);
- the restricting disk (40) is mounted below the adjuster screw (13) and is held in its position on the adjuster screw (13) by the locking screw (45) and the locking disc (40); and
- the spacer tube (50) located between the lower surface of the supporting piece (37) and a washer (60) and said washer (60) in communication with the main spring (65) for preload adjustment.

5. A preload adjuster (120) for front fork suspension of a two wheeled motor vehicle comprising of a top cap (1), a sensor (7), an adjuster screw (14) with sensing piece (8), an O-ring (15), a fork bolt (20), an O-ring (25), a lock nut (30), a sliding nut (35), a supporting piece (37), a restricting disk (40), a locking screw (45), a spacer tube (50), a washer (60), and a main spring (65); wherein
- the sensor (7) is mounted within a mounting hole (1c) given on the curved surface of the top cap (1) in a such way that lower surface of the sensor (7) is parallel to the outer surface of the sensing piece (8) which is accommodated within a recess (9) given on the adjuster screw (14);
- the O-ring (15) is mounted in a groove given on the adjuster screw (14) along the curved surface in contact with the fork bolt (20); and the O-ring (25) is mounted in a groove given on the fork bolt (20) along the curved surface in contact with an inner tube (55) of the front fork;
- the lock nut (30) is mounted in the fork bolt (20) on the threads given on the surface (14Q) of the adjuster screw (14) such that the upper surface of the lock nut (30) rests on the lower step on the adjuster screw (14);
- the sliding nut (35) is mounted below the locking nut (30) on the threads given on the surface (14Q) of the adjuster screw (14) and has one flat surface (35f) that rotationally locks the sliding nut (35) with an inside surface (20f) of the fork bolt (20) such that when the adjuster screw(14) is rotated, the sliding nut (35) remains free only to move linearly along the surface (14Q) of the adjuster screw (14);
- the supporting piece (37) is positioned below the sliding nut (35) on the adjuster screw (14) and has one surface that is supported on a lower surface of the sliding nut (35);
- the restricting disk (40) is mounted below the adjuster screw (14) and is held in its position on the adjuster screw (14) by the locking screw (45) and the locking disc (40); and
- the spacer tube (50) located between the lower surface of the supporting piece (37) and a washer (60) and said washer (60) in communication with the main spring (65) for preload adjustment.

6. The preload adjuster for front fork suspension of a two wheeled motor vehicle as claimed in claim 1 or 2, wherein
- the gear (5) is mounted eccentrically with reference to the central axis of the adjuster screw (10 and 11) and held in its location by a lower inside surface of the top cap (1); and
- each half of the gear teeth (5b) makes an angle (?) of 4.5° to 6.5° measured along the central axis of the adjuster screw.
7. The preload adjuster for front fork suspension of a two wheeled motor vehicle as claimed in claim 1 to 4, wherein the gears (5 and 6) has a plurality of gear teeth (5b and 6b) displaced at equal angles from each other, with the displacement angle between the gear teeth (5b and 6b) being measured along the central axis of the gears (5 and 6).

8. The preload adjuster for front fork suspension of a two wheeled motor vehicle as claimed in claim 5 or 7, wherein the adjuster screw (10, 11, 12, 13 and 14) has a recess (10a) along its top surface for allowing its interaction with device for imparting rotations with the recess (10a).

9. The preload adjuster for front fork suspension of a two wheeled motor vehicle as claimed in claim 7, wherein
- the window (1a) has a convex transparent cover (70) mounted on it so as to have clear and legible reading of numerals on the display surface (5a and 6a) of the gear (5 and 6); and
- the teeth (10b) is inclined at an angle of 85° - 100° degree with the imaginary line (L-L’) drawn perpendicular to the radial line passing through the center of the adjuster screw.

10. The preload adjuster for front fork suspension of a two wheeled motor vehicle as claimed in claim 3 or 4, wherein
- the gear (6) is configured to have a plurality of depression (6d) on the lower surface of said gear (6) corresponding to each of the gear teeth (6b); and
- said depression (6d) corresponding to meshed gear teeth (6b) accommodate a ball (21ba) against a spring (21sp) located within a circular recess (21re) of the fork bolt (21) to arrest the natural free rotation of the gear (6).

Dated this 18th day of August 2021.

Sahastrarashmi Pund
Head – IPR
Endurance Technologies Ltd.

To,
The Controller of Patents,
The Patent Office, at Mumbai. , Description:FORM 2
The Patent Act 1970
(39 of 1970)
&
The Patent Rules, 2005

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

TITLE OF THE INVENTION
“PRELOAD ADJUSTER FOR FRONT FORK SUSPENSION OF A TWO WHEELED MOTOR VEHICLE”

Endurance Technologies Limited
E-92, M.I.D.C. Industrial Area, Waluj,
Aurangabad – 431136, Maharashtra, India

The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed.
Field of Invention

[001] The present invention is related to front fork suspension of two wheeled motor vehicle. More particularly, the present invention relates to a preload adjusting mechanism in front fork suspension that indicates the preload setting for the user in each of the fork legs so as to have uniform preload setting in both the legs of the front fork suspension.

Background of the Invention

[002] The extent of pre-compression/preloading of a front fork suspension’s main spring determines how well a front fork suspension will help the wheels of a motor vehicle in following the profile of the road surface irregularities while maintaining the motor vehicle body at a desired level in different road conditions. Conventional front fork suspension are therefore provided with screw based mechanism for adjusting the pre-compression/preload of their main spring in both fork legs of a front fork suspension.

[003] While adjusting pre-compression/preload of the main spring enhances the rider comfort, adjusting the main spring’s pre-compression unequally in both the fork legs leads to creation of undesirable stresses in the front fork body during the motor vehicle’s operation. Development of these undesirable stresses, over a period of time, can negatively impact the durability and reliability of the front fork suspension. These pre-compression/preload adjustment mechanisms hence have to be carefully operated to ensure that main springs of both fork legs of the front fork suspension receive equal amount of preload adjustment. One conventional method of ensuring that equal pre-compression/preload adjustment involves turning the screw based preload adjustment mechanism by one turn at a time in both fork legs. This ensures that both fork legs of the front fork suspension have equal main spring pre-compression/preload even after turning of the screws. The disadvantage with this method is that once changes have been carried out any subsequent user, operator or maintenance engineer has no means of knowing the extent of main spring pre-compression/preload that has already been provided unless they are specifically informed about it. If this information is not transmitted for any reason the subsequent operator or maintenance engineer has to rely on a time consuming trial and error method of main spring pre-compression/preload adjustment to arrive at the settings that they find desirable.

[004] In some conventional front fork this problem has been resolved by providing external pre-compression/preload adjustment knobs with accompanying external markings on the fork legs for keeping operators and maintenance engineers aware of the settings. Such mechanisms even though they can measure and indicate the changes made for one turn of a the pre-compression/preload adjustment screw, they do not remain useful if the operator or maintenance engineer choose to give more than one turn to the adjustment screw for adjusting main spring pre-compression/preload.

[005] The existing solutions though each varying from the other in constructional features, each has its own drawback. Therefore, there is a long pending unmet need to provide a solution that addresses the above mentioned drawbacks and at the same time provides accurate and easy to read preload settings. The present invention, as described below, fill up the gap of the prior art and provides simple but equally user friendly solution solving the significant problem.

Objectives of the Invention

[006] The main objective of the present invention is to provide a preload adjustment mechanism that allows equal amount of pre-compression/preload adjustment to be made to both fork legs of a front fork suspension.
[007] Another object of the present invention is to provide a preload adjustment mechanism that indicates the extent of pre-compression/preload provided to the main springs of the different fork legs of the front fork.
[008] Yet, another object of the present invention is to provide a preload adjustment mechanism that aids resolving the problem of development of undesirable stresses during operation of front fork having unevenly adjusted main spring pre-compression/preload.
[009] Further, the object of the present invention is to provide a preload adjustment mechanism that ensures accuracy of the preload setting, simple in nature, user-friendly and easy to operate by the unskilled user as well.

Summary of the Invention

[0010] For achieving the stated objectives a preload adjuster for front fork suspension of a two wheeled motor vehicle is provided which comprises of a top cap, a gear, an adjuster screw with teeth, O-rings mounted on the fork bolt and the adjuster screw respectively, a fork bolt, a lock nut, a sliding nut, a supporting piece, a restricting disk, a locking screw, a spacer tube, a washer, and a main spring. The gear is mounted below the top cap on the fork bolt such that its mounting is offset with the central axis of the screw making the teeth of the adjuster screw is in mesh with an internal teeth of the gear at every rotational cycle of the adjuster screw. The top cap has a display window that is configured to indicate the numerical value marked on a display surface of the gear identifying each one of its multiple internal gear teeth. The O-ring is mounted in a groove given on the adjuster screw along the curved surface in contact with the fork bolt. The O-ring is mounted in a groove given on the fork bolt along the curved surface in contact with an inner tube of the front fork. The lock nut is mounted in the fork bolt on the threads given on the surface of the adjuster screw such that the upper surface of the lock nut rests on the lowest step on the adjuster screw. The sliding nut is mounted below the locking nut on the threads given on the surface of the adjuster screw and has one flat surface that rotationally locks the sliding nut with an inside surface of the fork bolt such that when the adjuster screw is rotated, the sliding nut remains free only to move linearly along the surface of the adjuster screw. The supporting piece is positioned below the sliding nut on the adjuster screw and has one surface that is supported on a lower surface of the sliding nut. The restricting disk is mounted below the adjuster screw and is held in its position on the adjuster screw by the locking screw and the locking disc. The spacer tube located between the lower surface of the supporting piece and a washer and said washer in communication with the main spring for preload adjustment.

[0011] Typically, the gear is mounted eccentrically with reference to the central axis of the adjuster screw and held in its location by a lower inside surface of the top cap. The gear has a plurality of gear teeth displaced at equal angles from each other, with the displacement angle between the gear teeth being measured along the central axis of the gear. Each half of the gear teeth makes an angle (?) of 4.5° to 6.5° measured along the central axis of the adjuster screw. The adjuster screw has a recess along its top surface for allowing its interaction with device for imparting rotations with the recess. The window has a convex transparent cover mounted on it so as to have clear and legible reading of numerals on the display surface of the gear. The teeth of the adjuster screw is inclined at an angle of 85° - 100° degree with the imaginary line drawn perpendicular to the radial line passing through the center of the screw.

Brief Description of the Drawings

[0012] This invention is illustrated in the accompanying drawings, throughout which like reference letters / numerals indicate corresponding parts in the various figures. The embodiments herein and advantages thereof will be better understood from the following description when read with reference to the following drawings, wherein
Figure 1a shows the isometric view and Figure 1b shows the top view of the preload adjuster in accordance with an embodiment of the present invention.
Figure 2 presents a cut sectional view of the preload adjuster disclosed in Fig. 1a in accordance with an embodiment of the present invention.
Figure 3 discloses an exploded assembly view of the preload adjuster in accordance with an embodiment of the present invention.
Figures 4a and 4b show an isometric view and bottom view, respectively of a top cap and Figure 4c shows an isometric view of a gear (5) of the preload adjuster in accordance with an embodiment of the present invention.
Figures 5a, 5b and 5c show the isometric view, side view and top view respectively of the adjuster screw of the preload adjuster in accordance with an embodiment of the present invention.
Figures 6a, 6b and 6c show the isometric view, side view and bottom view, respectively of the fork bolt of the preload adjuster in accordance with an embodiment of the present invention.
Figure 7 shows a top view of the preload adjuster without the top cap in accordance with an embodiment of the present invention.
Figures 8 and 9 shows an isometric view of the lock nut and the sliding nut, respectively of the preload adjuster in accordance with an embodiment of the present invention.
Figures 10a and 10b present an isometric view and exploded assembly view of the preload adjuster in accordance with the second embodiment of the present invention.
Figure 11 shows enlarged perspective view of the adjuster screw of the preload adjuster in accordance with the present invention.
Figures 12a and 12b show an isometric view and exploded assembly view, respectively of the preload adjuster in accordance with the third embodiment of the present invention.
Figures 13a and 13b show an isometric view and the bottom view, respectively of the gear (6) of the preload adjuster in accordance with an embodiment of the invention.
Figures 13c and 13d present an isometric view and bottom view respectively, of the fork bolt in accordance with an embodiment of the present invention.
Figures 14a and 14b show the top view and cut sectional view, respectively of the preload adjuster without the top cap in accordance with an embodiment of the invention.
Figures 15a and 15b show an isometric view and exploded assembly view of the preload adjuster in accordance with the fourth embodiment of the present invention.
Figures 16a, 16b and 16c show an isometric view, exploded assembly view and cut sectional view, respectively of the preload adjuster in accordance with the fifth embodiment of the present invention.

Detailed Description of the Present Invention

[0013] The invention will now be described in detail with reference to the accompanying drawings which must not be viewed as restricting the scope and ambit of the invention. Referring to Figures 1a, 1b, 2 and 3, the preload adjuster (100) in accordance with the current invention comprises of a top cap (1), a gear (5), an adjuster screw (10), an O-ring (15), a fork bolt (20), an O-ring (25), a lock nut (30), a sliding nut (35), a supporting piece (37), a restricting disk (40), a locking screw (45), a spacer tube (50), a washer (60) and a main spring (65). Referring to Figures 2 and 3, the gear (5) is mounted below the top cap (1) on the fork bolt (20) such that its mounting is offset with the central axis of the adjuster screw (10) making the teeth (10b) of the adjuster screw (10) is in mesh with an internal teeth of the gear (5) at every rotational cycle of the adjuster screw (10).

[0014] The top cap (1) has a display window (1a) that is configured to indicate the numerical value marked on a display surface (5a) of the gear (5) identifying each one of its multiple internal gear teeth (5b) (refer Figs. 2, 3, 4a, 4b and 4c). The window (1a) has a convex transparent cover (70) mounted on it so as to have clear and legible reading of numerals on the display surface (5a) of the gear (5). The top cap (1) also has a lower inside surface (1b) and an inner support surface (1c) which locate and support the gear (5). The lower inside surface (1b) of the top cap (1) is coated with friction material to prevent free rotation of the gear (5). The gear (5) is mounted eccentrically with reference to the central axis of the adjuster screw (10) and held in its location by a lower inside surface (1b) of the top cap (1) (refer Figs. 2, 4a, 4b and 4c). The gear (5) has a plurality of gear teeth (5b) displaced at equal angles from each other, with the displacement angle between the gear teeth (5b) being measured along the central axis of the gear (5) (refer Figs. 4c and 7). This ensures that movement of the gear (5), each time its teeth (5b) comes in contact with teeth (10b), would only indicate only one complete rotation of the adjuster screw (10). Each half of the gear teeth (5b) makes an angle ? measured along the central axis of the adjuster screw (10) (refer Figs. 4c and 7). The value of angle (?) a significant feature because it ensures that the numerical values marked on the display surface (5a) perfectly align with the display window (1a) of the top cap (1) and the said angle ? ranges from 4.5° to 6.5° with the central axis of the screw (10).

[0015] The O-ring (15) is mounted in a groove given on the adjuster screw (10) along the curved surface in contact with the fork bolt (20) (refer Figs. 5a and 5b). The adjuster screw (10) also has a recess (10a) along its top surface for allowing its interaction with device for imparting rotations (refer Figs. 5a and 5b). The teeth (10b) is inclined at an angle of 85° - 100° with the imaginary line (L-L’) drawn perpendicular to the radial line passing through the center of the screw (10) (refer Fig 5c). This angular range indicates the angle that must be provided to the teeth (10b) for ensuring that surface or line contact between the teeth (10b) of the screw and the teeth (5b) of the gear (5) does actually take place. Another O-ring (25) is mounted in a groove given on the fork bolt (20) along the curved surface in contact with an inner tube (55) of the front fork (refer Figs. 6a and 6b).

[0016] The lock nut (30) is mounted in the fork bolt (20) on the threads given on the surface (10Q) of the adjuster screw (10) such that the upper surface of the lock nut (30) rests on the lowest step on the adjuster screw (10) (refer Figs. 2, 5a and 8). The lock nut (30) restricts the vertical movement of the adjuster screw (10) while allowing the adjuster screw (10) to rotate freely along its central axis. The sliding nut (35) is mounted below the locking nut (30) on the threads given on the surface (10Q) of the adjuster screw (10) and has one flat surface (35f) that rotationally locks the sliding nut (35) with an inside surface (20f) of the fork bolt (20) such that when the adjuster screw (10) is rotated, the sliding nut (35) remains free only to move linearly along the surface (10Q) of the adjuster screw (10) (refer figs. 2, 5a, 8 and 9). The sliding nut (35) also has an upper support surface (35c) and a cylindrical curved surface (35q). The supporting piece (37) is positioned below the sliding nut (35) on the adjuster screw (10) and has one surface that is supported on a lower surface of the sliding nut (35).

[0017] The restricting disk (40) is mounted below the adjuster screw (10) and is held in its position on the adjuster screw (10) by the locking screw (45). The spacer tube (50) located between the lower surfaces of the supporting piece (37) and a washer (60) and said washer (60) is in communication with the main spring (65) for preload adjustment (refer Fig. 2). The fully assembled preload adjuster (100) is screwed onto the open end of the inner tube (55) of a front fork suspension of a two wheeled motor vehicle with matching threads given on the fork bolt (20) and the inner tube (55) facilitating creation of a tight joint. Optionally, a sealant can be applied during assembly to prevent leakage of damping fluid and provide an air tight joint between the preload adjuster (100) and the inner tube (55). A spacer tube (50) and a washer (60) are provided below the supporting piece (37) of the preload adjuster (100) in the inner tube (50) to reduce the length of the main spring (65) required to be provided in the front fork.

[0018] When the user, operator or the maintenance engineer desires to alter the preload of the main spring (65), the adjusting screw (10) must be rotated using a suitable rotating device at the recess (10a) (refer Figs. 2 and 5a). Once the rotation of the adjusting screw (10) is initiated, the teeth (10b) of the adjuster screw (10) start pushing the teeth (5b) of the gear (5). As the gear (5) is mounted below the top cap (1) on the fork bolt (20) such that its mounting is offset (by a distance of ?y considering distance between center points F and G given on the lines XF and XG, respectively) with the central axis of the adjuster screw (10) making the teeth (10b) of the adjuster screw (10) is in mesh with an internal teeth of the gear (5) (refer Fig. 7), the teeth (10b) stays in touch with teeth (5b) only until the moment the number marked for the second teeth (also identified as 5b) of the gear (5) arrives below at the window (1a) of the top cap (1) of the preload adjuster (100).

[0019] The gear (5) is located eccentrically with respect to the central axis of the adjuster screw (10) (refer Fig. 7). This fact influences when the teeth (5b) and teeth (10b) will engage and disengage when the adjuster screw (10) is rotated (refer Figs. 5a and 7). The matching threads given on the surface (10Q) and the sliding nut (35) can be altered so as to vary the amount pre-compression/preloading each rotation of the adjuster screw (10) provides to the main spring (65). The numbers marked on the display surface (5a) and the corresponding teeth (5b) can be increased in number to match the alterations so made to improve the resolution of the preload adjuster (100), thereby making it capable of measuring and indicating greater number of rotations of the adjuster screw (10).

[0020] The length of adjuster screw (10) corresponding to the surface (10Q) and the surface (10P) and the location of restricting disk (40) can be shifted vertically to alter the maximum amount of pre-compression/preload the preload adjuster (100) can provide. The changes are to be dictated by the requirements of the specific front fork in which the preload adjuster (100) is mounted. Normally, the preload adjuster (100) is designed to give pre-compression/preloading of 1mm to 25mm.

[0021] As the adjuster screw (10) is rotated, the locking nut (30) mounted on the threads given on the curved cylindrical surface (10Q) prevents upward displacement of the adjuster screw (10). As the adjuster screw (10) cannot be displaced upwards, it is the sliding nut (35) which is displaced downwards as the adjuster screw (10) is rotated. This happens because, the sliding nut (35) is rotationally locked because of interaction of its flat surface (35f) with the flat surface (20f) of the fork bolt (20) and the sliding nut (35) has its own internal threads that are in contact with threads provided on the curved cylindrical surface (10Q) of the adjuster screw (10), therefore rotation of adjuster screw (10) is translated into linear movement of the sliding nut (35). As the downward displacement of the sliding nut (35) also displaces the supporting piece (37), the spacer tube (50) and the washer (60), it causes corresponding compression of the main spring (65) as well. The frictional force setup between the threads of the adjuster screw (10) and the threads of the sliding nut (35) prevent any reverse rotation of the adjuster screw (10) when force being applied on the adjuster screw (10) to cause its rotation is withdrawn.

[0022] When the sliding nut (35) is just about to reach the lower end of threads given on the cylindrical curved surface (10Q) of the adjuster screw (10), the upper surface of the restricting disk (40) comes into contact with the base of the sliding nut (35) thereby stopping any further downward movement of the sliding nut (35). This feature therefore establishes an upper limit for the amount of pre-compression/preload that can be provided to the main spring (65) of the front fork suspension. The reverse rotation of the adjuster screw (10) causes upward displacement of the sliding nut (35) which in turn removes the pre-compression/preload applied on the main spring (65). The reverse rotation of the adjuster screw (10) also causes the teeth (10b) to rotate in reverse the gear (5) as it comes into contact with teeth (5b) at least once for every rotation of the adjuster screw (10).

[0023] Referring to Figs. 10a and 10b, the second embodiment i.e. a preload adjuster (105) for front fork suspension of two wheeled motor vehicle comprises of a top cap (1), a gear (5), an adjuster screw (11) with a ring (11B), an O-ring (15), a fork bolt (20), an O-ring (25), a lock nut (30), a sliding nut (35), a supporting piece (37), a restricting disk (40), a locking screw (45), a spacer tube (50), a washer (60), and a main spring (65). It is pertinent to mention over here that similarly numbered parts of the first and second embodiments have the same structure and function.

[0024] The adjuster screw (11) has a ring (11B) screwed on its top using a screw (11A) and said ring (11B) has an internal projection (11BP) that locks with a recess (11R) given at the top of the adjuster screw (11) to prevent its rotation with respect to the adjuster screw (11) (refer Figs. 10b and 11). The gear (5) is mounted below the top cap (1) on the fork bolt (20) such that a teeth (10b) of the ring (11B) is in mesh with at least one internal teeth (5b) of the gear (5) at every rotational cycle of the adjuster screw (11). This is possible only because, the gear (5) is mounted below the top cap (1) on the fork bolt (20) such that its mounting is offset (by a distance of ?y considering distance between center points F and G given on the lines XF and XG, respectively) with the central axis of the adjuster screw (11) making the teeth (10b) of the adjuster screw (11) is in mesh with an internal teeth of the gear (5) at every rotational cycle of the adjuster screw (11) (refer Fig 7).

[0025] The top cap (1) has a display window (1a) that is configured to indicate the numerical value marked on a display surface (5a) of the gear (5) identifying each one of its multiple teeth (5b) (refer Figs. 4a, 4b and 4c). The window (1a) has a convex transparent cover (70) mounted on it so as to have clear and legible reading of numerals on the display surface (5a) of the gear (5). The top cap (1) also has a lower inside surface (1b) and an inner support surface (1c) which locate and support the gear (5). The lower inside surface (1b) of the top cap (1) is coated with friction material to prevent free rotation of the gear (5). The gear (5) is mounted eccentrically with reference to the central axis of the adjuster screw (11) and held in its location by a lower inside surface (1b) of the top cap (1) (refer Figs. 4a, 4b and 4c). The gear (5) has a plurality of gear teeth (5b) displaced at equal angles from each other, with the displacement angle between the gear teeth (5b) being measured along the central axis of the gear (5) (refer Figs. 4c and 7). This ensures that movement of the gear (5), each time its teeth (5b) comes in contact with teeth (10b), would only indicate only one complete rotation of the adjuster screw (11). Each half of the gear teeth (5b) makes an angle (?) of 4.5° to 6.5° measured along the central axis of the adjuster screw (11) (refer Figs. 4c and 7).

[0026] The O-ring (15) is mounted in a groove given on the adjuster screw (11) along the curved surface in contact with the fork bolt (20) (refer Figs. 5a and 5b). The adjuster screw (11) also has a recess (10a) along its top surface for allowing its interaction with device for imparting rotations (refer Figs. 10b and 11). The teeth (10b) is inclined at an angle of 85° - 100° with the imaginary line (L-L’) drawn perpendicular to the radial line passing through the center of the screw (11) (refer fig 5c). This angular range indicates the angle that must be provided to the teeth (10b) for ensuring that contact between the teeth (10b) and the teeth (5b) does actually take place. Another O-ring (25) is mounted in a groove given on the fork bolt (20) along the curved surface in contact with an inner tube (55) of the front fork (refer figs. 6a and 6b).

[0027] The lock nut (30) is mounted in the fork bolt (20) on the threads given on the surface (11Q) of the adjuster screw (11) such that the upper surface of the lock nut (30) rests on the lowest step on the adjuster screw (11) (refer Figs. 10b and 11). The lock nut (30) restricts the vertical movement of the adjuster screw (11) while allowing the adjuster screw (11) to rotate freely along its central axis. The sliding nut (35) is mounted below the locking nut (30) on the threads given on the surface (11Q) of the adjuster screw (11) and has one flat surface (35f) that rotationally locks the sliding nut (35) with an inside surface (20f) of the fork bolt (20) such that when the adjuster screw (11) is rotated, the sliding nut (35) remains free only to move linearly along the surface (11Q) of the adjuster screw (11) (refer Figs. 5a, 8 and 9). The sliding nut (35) also has an upper support surface (35c) and a cylindrical curved surface (35q). The supporting piece (37) is positioned below the sliding nut (35) on the adjuster screw (11) and has one surface that is supported on a lower surface of the sliding nut (35).

[0028] The restricting disk (40) is mounted below the adjuster screw (11) and is held in its position on the adjuster screw (11) by the locking screw (45). The spacer tube (50) located between the lower surfaces of the supporting piece (37) and a washer (60) and said washer (60) in communication with the main spring (65) for preload adjustment (refer Fig. 10b). The fully assembled preload adjuster (105) is screwed onto the open end of the inner tube (55) of a front fork suspension of a two wheeled motor vehicle with matching threads given on the fork bolt (20) and the inner tube (55) facilitating creation of a tight joint. Optionally, a sealant can be applied during assembly to prevent leakage of damping fluid and provide an air tight joint between the preload adjuster (105) and the inner tube (55). A spacer tube (50) and a washer (60) is provided below the supporting piece (37) of the preload adjuster (105) in the inner tube (50) to reduce the length of the main spring (65) required to be provided in the front fork.

[0029] When the operator or the maintenance engineer desires to alter the preload of the main spring (65), the adjusting screw (11) must be rotated using a rotating device as explained above. The gear (5) is located eccentrically with respect to the central axis of the adjuster screw (11) (refer Fig. 7). This fact influences when the teeth (5b) and teeth (10b) will engage and disengage when the adjuster screw (11) is rotated (refer figs. 7 and 11). The matching threads given on the surface (11Q) and the sliding nut (35) can be altered to so as to vary the amount pre-compression/preloading each rotation of the adjuster screw (11) provides to the main spring (65). The numbers marked on the display surface (5a) and the corresponding teeth (5b) can be increased in number to match the alterations so made to improve the resolution of the preload adjuster (105), thereby making it capable of measuring and indicating greater number of rotations of the adjuster screw (11).

[0030] The length of adjuster screw (11) corresponding to the surface (11Q) and the surface (11P) and the location of restricting disk (40) can be shifted vertically to alter the maximum amount of pre-compression/preload the preload adjuster (105) can provide. As the adjuster screw (11) is rotated, the locking nut (30) mounted on the threads given on the curved cylindrical surface (11Q) prevents upward displacement of the adjuster screw (11). As the adjuster screw (11) cannot be displaced upwards, it is the sliding nut (35) which is displaced downwards as the adjuster screw (11) is rotated. This happens because, the sliding nut (35) is rotationally locked because of interaction of its flat surface (35f) with the flat surface (20f) of the fork bolt (20) and the sliding nut (35) has its own internal threads that are in contact with threads provided on the curved cylindrical surface (11Q) of the adjuster screw (11), therefore rotation of adjuster screw (11) is translated into linear movement of the sliding nut (35). As the downward displacement of the sliding nut (35) also displaces the supporting piece (37), the spacer tube (50) and the washer (60), it causes corresponding compression of the main spring (65).

[0031] When the sliding nut (35) is just about to reach the lower end of threads given on the cylindrical curved surface (11Q) of the adjuster screw (11), the upper surface of the restricting disk (40) comes into contact with the base of the sliding nut (35) thereby stopping any further downward movement of the sliding nut (35). This feature therefore establishes an upper limit for the amount of pre-compression/preload that can be provided to the main spring (65) of the front fork suspension. The reverse rotation of the adjuster screw (11) causes upward displacement of the sliding nut (35) which in turn removes the pre-compression/preload applied on the main spring (65). The reverse rotation of the adjuster screw (11) also causes the teeth (10b) to rotate in reverse the gear (5) as it comes into contact with teeth (5b) at least once for every rotation of the adjuster screw (11).

[0032] When the user, operator or the maintenance engineer desires to alter the preload of the main spring (65), the adjusting screw (11) is rotated with a suitable rotating device at the recess (10a). Once the rotation of the adjusting screw (11) is initiated, the teeth (10b) of the adjuster screw (11) start pushing the teeth (5b) of the gear (5). The teeth (10b) stays in touch with teeth (5b) only until the moment the number marked for the second teeth (also identified as 5b) of the gear (5) arrives below at the window (1a) of the top cap (1) of the preload adjuster (105). The manner in which the preload adjuster (105) functions is the same as that of the preload adjuster (100) as explained above. The main technical advantage of second embodiment of the present invention is that the ring (11B) of the adjuster screw (11) can be replaced very easily in case the teeth (10b) integrated with it wears out due friction.

[0033] Referring to Figs. 12a and 12b, the third embodiment i.e. a preload adjuster (110) for front fork suspension of two wheeled motor vehicle comprises of a top cap (1), a gear (6), an adjuster screw (12) with a ring (11B), a fork bolt (21), an O-ring (25), a lock nut (30), a sliding nut (35), a supporting piece (37), a restricting disk (40), a locking screw (45), a spacer tube (50), a washer (60), and a main spring (65). It is pertinent to mention over here that similarly numbered parts of the second and third embodiments have the same structure and function.

[0034] The adjuster screw (12) has a ring (11B) screwed on its top using a screw (11A) and the adjuster screw ring (11B) has an internal projection (11BP) that locks with a recess (11R) given at the top of the adjuster screw (12) as shown in Fig. 12b. The gear (6) is mounted below the top cap (1) on the fork bolt (21) in such way that the central axis of the gear (6) is parallel with the central axis of the screw (12) and teeth (10b) of the ring (11B) is in mesh with at least one external teeth (6b) of the gear (6) at every rotational cycle of the adjuster screw (12) (refer Figs. 14a and 14b). The indicated points G and F are center points of the gear (6) and adjuster screw (12) respectively when viewed from the top. Referring Figs. 13a, 13b and 13c, the gear (6) is mounted in the support hole (21h) of the fork bolt (21) with the help of a screw (6P). The top cap (1) has a display window (1a) that indicates the numerical value marked on a display surface (6a) of the gear (6) identifying each one of its multiple internal gear teeth (6b). Furthermore, a ball (21ba) and a spring (21sp) is located (given in the order) within a circular recess (21re) of the fork bolt (21) at a location immediately below the gear (6). The gear (6) has multiple depressions (6d) on its lower surface which correspond to each of its gear teeth (6b). The depressions (6d) allow the ball (21ba) to rest within themselves when the gear (6) rotates and thereby the depression (6d) moves above the recess (21re) in which the ball (21ba) and spring (21sp) are positioned (refer Figs. 13a, 13b, 13c and 14b). This arrests the natural free rotation of the gear (6), if any due to vibrations / jerks and/or any other factors. The gear (6) will be rotatable unless a significant force is applied to rotate the gear (6) (by the adjuster screw (12)) to overcome the force applied by the spring (21sp) on the gear (6) via the ball (21ba). The threads given on the cylindrical curved surface (21b) of the fork bolt (21) interact with matching threads given on the inner surface of the inner tube (55) to prevent rotation of the fork bolt (21) with respect to the inner tube (55).

[0035] The O-ring is mounted in a groove given on the adjuster screw (12) along the curved surface in contact with the fork bolt (21). The O-ring (25) is mounted in a groove given on the fork bolt (21) along the curved surface in contact with an inner tube (55) of the front fork. The lock nut (30) is mounted in the fork bolt (21) on the threads given on the surface (11Q) of the adjuster screw (12) such that the upper surface of the lock nut (30) rests on the lowest step on the adjuster screw (12). The sliding nut (35) is mounted below the locking nut (30) on the threads given on the surface (11Q) of the adjuster screw (12) and has one flat surface (35f) that rotationally locks the sliding nut (35) with an inside surface (21f) of the fork bolt (21) such that when the adjuster screw (12) is rotated, the sliding nut (35) remains free only to move linearly along the surface (11Q) of the adjuster screw (12) (refer figs. 12b and 13d). The supporting piece (37) is positioned below the sliding nut (35) on the adjuster screw (12) and has one surface that is supported on a lower surface of the sliding nut (35). The restricting disk (40) is mounted below the adjuster screw (12) and is held in its position on the adjuster screw (12) by the locking screw (45) and the locking disc (40). The spacer tube (50) located between the lower surface of the supporting piece (37) and a washer (60) and said washer (60) in communication with the main spring (65) for preload adjustment.

[0036] The gear (6) has a plurality of gear teeth (6b) displaced at equal angles from each other, with the displacement angle between the gear teeth (6b) being measured along the central axis of the gear (6) (refer Figs. 14a and 14b). This ensures that movement of the gear (6), each time its teeth (6b) comes in contact with teeth (10b), would only indicate only one complete rotation of the adjuster screw (12). The adjuster screw (12) has a recess (10a) along its top surface for allowing its interaction with device for imparting rotations with the recess (10a). The window (1a) has a convex transparent cover (70) mounted on it so as to have clear and legible reading of numerals on the display surface (6a) of the gear (6).

[0037] The ring (11B) of the adjuster screw (12) can be very easily replaced when the teeth (10b) wears out. The gear (6), its structure and positioning on the fork bolt (21) with respect to the central axis of the adjuster screw (12) makes the third embodiment unique in terms of easy replacement of components (viz. the gear (6), the ring (11B) and like) in case of failure and/or wear out as compared to the prior art solutions for preload adjustment. Other structural characteristics and the manner in which the preload adjuster (110) functions is similar to that of the first and second embodiments of the preload adjuster and hence the further description of the same is omitted.

[0038] Referring to Figures 15a and 15b, the fourth embodiment i.e. a preload adjuster (115) for front fork suspension of a two wheeled motor vehicle comprises of a top cap (1), a gear (6), an adjuster screw (13) with teeth (10a), an O-ring, a fork bolt (21), an O-ring (25), a lock nut (30), a sliding nut (35), a supporting piece (37), a restricting disk (40), a locking screw (45), a spacer tube (50), a washer (60), and a main spring (65). The gear (6) is mounted below the top cap (1) on the fork bolt (21) in such way that the central axis of the gear (6) is parallel with the central axis of the screw (13) and the teeth (10b) of the adjuster screw (13) is in mesh with at least one external teeth (6b) of the gear (6) at every rotational cycle of the adjuster screw (13) (refer Fig. 14a). The indicated points G and F are center points of the gear (6) and adjuster screw (13) respectively when viewed from the top. The top cap (1) has a display window (1a) that is configured to indicate the numerical value marked on a display surface (6a) of the gear (6) identifying each one of its multiple internal gear teeth (6b). Furthermore, a ball (21ba) and a spring (21sp) is located (given in the order) within a circular recess (21re) of the fork bolt (21) at a location immediately below the gear (6). The gear (6) has multiple depressions (6d) on its lower surface which correspond to each of its gear teeth (6b). The depressions (6d) allow the ball (21ba) to rest within themselves when the depression (6d) moves above the recess (21re) in which the ball (21ba) and spring (21sp) are positioned (refer figs. 13a, 13b, 13c and 14b). This thereby prevents any free rotation of the gear (6) unless a significant force is applied to rotate the gear (6) (by the adjuster screw (13)) to overcome the force applied by the spring (21sp) on the gear (6) via the ball (21ba). The threads given on the cylindrical curved surface (21b) of the fork bolt (21) interact with matching threads given on the inner surface of the inner tube (55) to prevent rotation of the fork bolt (21) with respect to the inner tube (55).

[0039] The O-ring is mounted in a groove given on the adjuster screw (10) along the curved surface in contact with the fork bolt (21). The O-ring (25) is mounted in a groove given on the fork bolt (21) along the curved surface in contact with an inner tube (55) of the front fork. The lock nut (30) is mounted in the fork bolt (21) on the threads given on the surface (10Q) of the adjuster screw (13) such that the upper surface of the lock nut (30) rests on the lower step on the adjuster screw (13). The sliding nut (35) is mounted below the locking nut (30) on the threads given on the surface (10Q) of the adjuster screw (13) and has one flat surface (35f) that rotationally locks the sliding nut (35) with an inside surface (21f) of the fork bolt (21) such that when the adjuster screw (13) is rotated, the sliding nut (35) remains free only to move linearly along the surface (10Q) of the adjuster screw (13). The supporting piece (37) is positioned below the sliding nut (35) on the adjuster screw (13) and has one surface that is supported on a lower surface of the sliding nut (35). The restricting disk (40) is mounted below the adjuster screw (13) and is held in its position on the adjuster screw (13) by the locking screw (45) and the locking disc (40). The spacer tube (50) located between the lower surface of the supporting piece (37) and a washer (60) and said washer (60) in communication with the main spring (65) for preload adjustment.

[0040] The gear (6) has a plurality of gear teeth (6b) displaced at equal angles from each other, with the displacement angle between the gear teeth (6b) being measured along the central axis of the gear (6) (refer Fig. 14a). This ensures that movement of the gear (6), each time its teeth (6b) comes in contact with teeth (10b), would only indicate only one complete rotation of the adjuster screw (13). The adjuster screw (13) has a recess (10a) along its top surface for allowing its interaction with device for imparting rotations with the recess (10a). The window (1a) has a convex transparent cover (70) mounted on it so as to have clear and legible reading of numerals on the display surface (6a) of the gear (6). The gear (6), its structure and positioning on the fork bolt (21) with respect to the central axis of the adjuster screw (13) makes the fourth embodiment more modular in light of its serviceability. Other structural characteristics and the manner in which the preload adjuster (115) functions is similar to that of the previous embodiments as described above.

[0041] Referring to Figs. 16a, 16b and 16c, the fifth embodiment i.e. a preload adjuster (120) for front fork suspension of a two wheeled motor vehicle comprises of a top cap (1), a sensor (7), an adjuster screw (14) with sensing piece (8), an O-ring (15), a fork bolt (20), an O-ring (25), a lock nut (30), a sliding nut (35), a supporting piece (37), a restricting disk (40), a locking screw (45), a spacer tube (50), a washer (60), and a main spring (65). The sensor (7) is mounted within a mounting hole (1c) given on the curved surface of the top cap (1) in a such way that lower surface of the sensor (7) is parallel to the outer surface of the sensing piece (8) which is accommodated within a recess (9) given on the adjuster screw (14) (refer fig. 16b and 16c). The O-ring (15) is mounted in a groove given on the adjuster screw (14) along the curved surface in contact with the fork bolt (20). The O-ring (25) is mounted in a groove given on the fork bolt (20) along the curved surface in contact with an inner tube (55) of the front fork.

[0042] The lock nut (30) is mounted in the fork bolt (20) on the threads given on the surface (12Q) of the adjuster screw (14) such that the upper surface of the lock nut (30) rests on the lower step on the adjuster screw (14). The sliding nut (35) is mounted below the locking nut (30) on the threads given on the surface (14Q) of the adjuster screw (14) and has one flat surface (35f) that rotationally locks the sliding nut (35) with an inside surface (20f) of the fork bolt (20) such that when the adjuster screw (14) is rotated, the sliding nut (35) remains free only to move linearly along the surface (14Q) of the adjuster screw (14). The supporting piece (37) is positioned below the sliding nut (35) on the adjuster screw (14) and has one surface that is supported on a lower surface of the sliding nut (35). The restricting disk (40) is mounted below the adjuster screw (14) and is held in its position on the adjuster screw (12) by the locking screw (45) and the locking disc (40). The spacer tube (50) located between the lower surface of the supporting piece (37) and a washer (60) and said washer (60) in communication with the main spring (65) for preload adjustment.

[0043] The parts having similar structure and function as in the other embodiments have been given the same identification number in fifth embodiment as well. The functioning of the fifth embodiment differs from that of the other embodiments in that the sensor (7) provided in the sensor hole (1c) measures the number of times the sensing piece (8) passes from underneath it when adjuster screw (14) is rotated. The sensor (7) can be any sensor that is capable of registering passage of magnet or an un-magnetized metallic piece used as the sensing piece (8). The sensing piece (8) has to have a shape that can restrict all its degrees of freedom when it is placed within the recess (9) on the adjuster screw (14). Sensor and sensing piece combination as such can be varied so as to accommodate the set having the maximum accuracy, the smallest size and weight. The preload adjuster (120) with its sensor (7) and the sensing piece (8) pair provides preload/pre-compression adjustment data that is processed by a control unit and displayed on a handlebar mounted display unit of the motor vehicle. Using sensor (7) and sensing piece (8) combination makes the fifth embodiment of the preload adjuster more sensitive and more accurate in comparison to other embodiments of the preload adjuster. This is so because it has no sub-components that can slip and move or distort under load applied to change the preload/pre-compression on the main spring (65). Other structural characteristics and the manner in which the preload adjuster (120) functions is similar to that of the other embodiments of the preload adjuster and hence further description of the same is omitted.

[0044] The technical advancements and advantages derived from the novel features of the embodiments of the present invention as disclosed and described in detail are as follows:
- It provides an accurate reading of the extent of pre-compression/preload applied to the main spring of the front fork even beyond one complete rotation of the adjuster screw.
- It has a greater resolution allowing multiple rotations of the adjuster screw to be accurately indicated in its display window.
- It provides a very important safety feature which prevent over rotation of the adjuster screw and hence over compression of the main spring of the front fork suspension. Thus, it ensures the safety of preload adjustment and thereby suspension system.
- It allows accurate adjustment of pre-compression/preload in each leg of the front fork suspension in which they are provided. Therefore, it leads to prevention of developing undesirable stress in the front fork that during vehicle operation that happens due to unequal pre-compression/preload adjustment in a front fork.
- The O-rings provided on the adjuster screw and the fork bolt respectively provide an effective seal which prevents leakage of damping fluid from the front fork and also ingestion of dust or other foreign material into the front fork from the environment.
- These solutions are easy to service and easy for maintenance. It imparts modularity to the preload adjustment assembly which enable the user to replace desired part / component only in case wear and tear.
- These provide economic solutions to that any unskilled user/technician can ensure uniform and equal preload in each of the fork legs for the desired suspension effect.
- The embodiments of the invention make the existing front fork suspension system to upgrade with the new features or replace the existing preload assembly with that disclosed in the invention without any structural change / modification in the front fork assembly.

[0045] It must be noted that parts having the same construction and function have been given the same numbers across all the embodiments described. It must be further noted that, the matching threads given on the surface adjuster screw and the sliding nut can be altered to so as to vary the amount pre-compression/preloading each rotation of the adjuster screw provides to the main spring. The numbers marked on the display surface and the corresponding teeth on the gear can be increased in number to match the alteration so made to improve the resolution of the preload adjuster, thereby making it capable of measuring and indicating greater number of rotations of the adjuster screw. The position of the gear can be easily optimized with respect to that the adjuster screws position to ensure that every complete rotation is faithfully indicated even when number of gear teeth are changed. The length of adjuster screw corresponding to its surface provided with threads and the location of restricting disk can be shifted vertically to alter the maximum amount of pre-compression/preload the preload adjuster can provide. All these changes are dictated by the requirements of the specific front fork in which the preload adjuster is mounted. As all such alterations would be obvious to a person skilled in the art, they must therefore be considered to be lying within the scope of the invention described.

[0046] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.