DESC: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
“INVERTED FRONT FORK SUSPENSION WITH OPTIMIZED ADAPTOR BUSH FOR A TWO WHEELED 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 an inverted front fork suspension for a two wheeled vehicle. More particularly, the invention is related to an adaptor bush for the inverted front fork of a vehicle, wherein the adaptor bush is uniquely designed and made of sintered steel to reduce friction of the active coil of the spring, avoid rusting of the adaptor bush, and provide a cost-effective solution.

Background of the Invention

[002] In order to provide better riding comfort, the vehicles are equipped with dampening arrangements. These dampening arrangements reduce the impact and vibrations that are caused by the uneven road. Conventionally, various kinds of inventions have been made for front forks mounted on a motorcycle to absorb impact and vibrations and each of these inventions do have varying degree of success.

[003] An inverted front fork design has been proposed in recent years to make the bike more rigid and improve handling. In such an inverted front fork, the inner tube is mounted on the wheel side by the lower bracket, and the outer tube is mounted on the handle side by the upper bracket. In the conventional inverted type of front fork, one end of the piston rod is fitted with the upper bracket, where the top end of the outer tube is already fitted, and the other end of the piston rod has a damping assembly and piston assembly. The said piston assembly and damping assembly are movably placed inside the cartridge tube, which is filled with oil. One end of the said cartridge tube is fixed with an axle bracket, and the other end of the cartridge tube is connected to an adaptor bush. The adaptor bush is generally configured to have a hollow shaft and a circular collar around the said hollow shaft. The inner diameter of the hollow shaft has a step profile that is configured to receive the bottom end of the spring guide. The outer diameter of the hollow shaft is configured to receive a spring and abuts over the circular collar that are provided around the said hollow shaft.

[004] In the above-mentioned arrangement, a large number of active coils of the spring are in contact with the outer diameter of the said hollow shaft of the adaptor bush, which leads to the problem of friction between the spring coils and the outer surface of the hollow shaft and also reduces the count of active coils of the spring. Further, the above-mentioned adaptor bush is generally made of steel or aluminum, which requires extensive machining, resulting in a high production cost and increased cycle time to manufacture the same.

[005] Therefore, to address the aforementioned limitations of the prior art solutions, there is a long pending unmet need to provide an intelligent solution that not only ensures the locking of only the dead coil of the spring but avoids the issue of rusting, improves the bottoming load, and provides a cost effective solution as well.

Objectives of the Invention

[006] The main objective of the present invention is to provide an adaptor bush for an inverted front fork for a vehicle.

[007] Another objective of the present invention is to provide an adaptor bush for an inverted front fork that reduces the friction of the spring’s coil.
[008] Yet, another objective of the present invention is to provide an adaptor bush for an inverted front fork that is simple to manufacture and cost-effective.

[009] Yet, another objective of the present invention is to reduce the weight of the adaptor bush and consequently thereby the weight of an inverted front fork.

[0010] Yet, another objective of the present invention is to provide an adaptor bush for an inverted front fork which provides constant bottoming load thereby reducing the wear and tear of components of the front fork suspension.

[0011] Still, the objective of the present invention is to provide an adaptor bush for an inverted front fork that is configured to reduce the rusting of components and thereby imparts the at par performance of the front fork suspension system.

Brief Description of the Drawings

[0012] This invention is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The disclosure herein and advantages thereof will be better understood from the following description when read with reference to the following drawings, wherein

[0013] Figure 1 discloses a break view of an inverted front fork of the vehicle in accordance with the present invention.

[0014] Figure 2 discloses a sectional view of an inverted front fork of the vehicle in accordance with the present invention.
[0015] Figure 3 discloses an exploded view of an adaptor bush with spring and cartridge tube in accordance with the first embodiment of the present invention.

[0016] Figure 4 discloses an exploded view of an adaptor bush with spring and cartridge tube in accordance with the second embodiment of the present invention.

[0017] Figure 5 discloses an enlarged sectional view of the portion of the inverted front fork suspension clearly disclosing the adaptor bush of the present invention.

[0018] Figures 6a and 6b disclose an isometric view and cut-section view, respectively of the adaptor bush in accordance with the first embodiment of the present invention.

[0019] Figures 7a and 7b disclose an isometric view and cut-section view, respectively of the adaptor bush in accordance with the second embodiment of the present invention.

Detailed Description of the Present Invention

[0020] 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. In accordance with the disclosed embodiment of the present invention, an inverted fork (1000) for a two wheeled vehicle comprises of an outer tube (10), an inner tube (20), a uniquely profiled adaptor bush (90, 90’), a fork bolt (30), a seal assembly (40), a lock bolt (50), a bottom axle bracket (60), a main spring (70), a spring guide (80), a cartridge tube (100), a piston rod (110) with piston assembly (120), and a rebound assembly (140).
[0021] The fork bolt (30) is configured to have a collar (30C) and an annular body (30A). The collar (30C) of the fork bolt (30) have a circular lug (30L), which is projected from the outer periphery of the collar (30C) in the direction of the annular body (30A). The lug (30L) is projected towards the annular body (30A) in such manner that a circular groove (30G) is concentrically created in between the outer diameter of the annular body (30A) and inner diameter of the lug (30L). The said circular groove (30G) is configured to receive a set of spacer (S) for pre-compression. Further, the outer diameter of the lug (30L) is configured to have a threaded portion (32) for accommodating an upper end of the outer tube (10) through the threaded jonery. The said annular body (30A) has an opening (30T) for receiving an end of the piston rod (110). The piston rod (110) is fitted inside the opening (30T) of the fork bolt (30) by threading mechanism. Further, the other end of the piston rod (110) is fitted with a piston assembly (120) and a rebound assembly (140).

[0022] The spring guide (80) is configured to have an upper end (80U), a lower end (80L) and a longitudinal central opening (80C). The upper end (80U) of the spring guide (80) is moulded with a lock nut (82). The lower end (80L) of the spring guide (80) is configured to have a step profile (SP) on the inner peripheral surface and said step profiled is configured to create a clearance (C) with the piston rod (110). The said step profile (SP) of the spring guide (80) and the clearance (C) is configured to form an oil / hydraulic lock (HL) with the central opening (90C) of the adaptor bush (90) during the extreme compression stroke of the inverted fork (1000). The said spring guide (80) is sleeved over the piston rod (110) through the longitudinal central opening (80C). Further, the lock nut (82) is interlocked with the annular body (30A) of the fork bolt (30) by a threading mechanism. The main spring (70) is sleeved over the spring guide (80) and positioned in such a way that its upper end (E1) abuts with the set of spacers (S) in the outer tube (10) and its lower end (E2) rests over the collar (95, 95’) of the adaptor bush (90) in the inner tube (20).

[0023] Referring to Figs. 6a and 6b, the adaptor bush (90, 90’) is made of sintered metal such as steel. The said adaptor bush (90, 90’) is configured to have a central opening (90C), a conical body portion (92), a cylindrical portion (96), and a collar (95, 95’). The said collar (95, 95’) projects out in radial direction from the base portion (92B) of the conical portion (92) and said base portion (92B) of the conical portion (92) is configured to merge with the cylindrical portion (96) to form a unitary structure of the adapter bush (90, 90’). The collar (95, 95’) of the adaptor bush (90, 90’) is projected out from the outer peripheral surface of the base portion (92B) of the conical body portion (92).

[0024] The said conical portion (92) is configured to have a plurality of ribs (94) running in axial direction on the outer peripheral surface of the conical portion (92) of the adaptor bush (90). The most optimized and preferred number of ribs (94) is four ribs (94) and each of the ribs (94) is configured to have a lower portion (94L) and an upper portion (94U). The lower portion (94L) of the ribs (94) is formed from the top surface of the collar (95, 95’) and the upper portion (94U) is formed at the extreme end of the conical body portion (92) of the adapter bush (90, 90’). The said ribs (94) are profiled in such a way that the width of the lower portion (94L) is greater than the width of the upper portion (94U) of the thereby making the trapezoidal cross section of the ribs (94). This optimized trapezoidal profile of the ribs (94) facilitates to reduce the weight of the adaptor bush (90, 90’) while keeping the mechanical properties of the adaptor bush (90, 90’) intact.

[0025] The base portion (92B) of the adaptor bush (90, 90’) that merges with the collar (95, 95’) of the adaptor bush (90, 90’) is configured to have outer diameter greater than the outer diameter of the extreme end thereby forming a conical profile of the body portion (92). This difference in outer diameters of the conical body portion (92) of the adaptor bush (90, 90’) forms a taper profile on the outer peripheral surface of the body portion (92) making a taper angle (a) with the vertical. This taper angle (a) effectively facilitate in drastically reducing the friction between the main spring (70) and body portion (92) of the adaptor bush (90. 90’) and varies from 3 degrees to 10 degrees.

[0026] The lower end (E2) of the main spring (70) rests on the collar (95, 95’) of the adaptor bush (90, 90’) encircling the conical body portion (92) maintaining the sufficient clearance between the main spring (70) and the body portion (92) of the adaptor bush (90) thereby avoiding the friction and consequently the wear and tear of the adaptor bush (90).

[0027] The cylindrical portion (96) of the adaptor bush (90) is configured to orthogonally project in downward direction from the collar (95, 95’). The outer peripheral surface of the cylindrical portion (96) has a circular groove (98) and said circular groove (98) facilitates to get the adaptor bush (90, 90’) fitted with the open end of the cartridge tube (100) by spinning and grooving operation. However, the adaptor bush (90, 90’) can be fitted with the cartridge tube (100) by the treaded joinery. In this case, then the outer peripheral surface of the cylindrical body portion (96) of the adaptor bush (90, 90’) has threads instead of the circular groove (98) and said threads are configured to mesh with the threads provided on the inner peripheral surface of the cartridge tube (100) to have the positive locking of said adaptor bush (90, 90’) with the cartridge tube (100).

[0028] The said central opening (90C) of the adaptor bush (90, 90’) is thorough and is configured to form a multi-step profile (ST). The multi-step profile (ST) of the central opening (90C) of the adaptor bush (90, 90’) forms a first step profile (ST1) which is configured to receive the stepped end (80L) of the spring guide, a second step profile (ST2) which is configured to house the bush (BH), and the third step profile (ST3) which is configured to guide the piston rod (110). The first step profile (ST1) at its bottom end is configured to have a groove (90G) to receive an O-ring (OR) therein. The said O-ring (OR) is made of rubber and is positioned in an O-Ring groove (90G) to avoid the sudden impact of the spring guide (80) with the bottom face of the first step profile (ST1) during the extreme compression stroke thereby creating a cushioning effect therein during the bottoming of the spring guide (80). The bush (BH) positioned in the second step profile (ST2) is configured to control the friction and wear and tear of the piston rod (110).

[0029] The lower end of the cartridge tube (100) is positioned over the base tab (BT) and is locked there by the press fitting. This lower end of the cartridge tube (100) is configured to have an orifice (H) just above the base tab (BT) and orifice (H) of the cartridge tube (100) allows the flow of fluid from the cartridge tube (100) to the inner tube (20) and vice-versa during working of the inverted front fork. The base tab (BT) is fitted with the bottom axle bracket (60) by using the lock bolt (50) through a threading mechanism. The cartridge tube (100) is configured to accommodate the piston assembly (120) and the rebound assembly (140) mounted on the lower end of the piston rod (110) passing through the adaptor bush (90, 90’). The piston rod (110) along with the piston assembly (120) and rebound assembly (140) is configured to slide within the cartridge tube (100) in downward and upward direction during the compression and rebound stroke, respectively during the working of the front fork suspension. The said cartridge tube (100) is filled with the working fluid, preferably the oil.

[0030] The inner tube (20) is concentrically sleeved over the cartridge tube (100) and is fitted with the axle bracket (60) by press fitting followed by welding or through the threaded joinery in such a way that it creates an annular chamber for the oil in between the inner peripheral surface of the inner tube (20) and the outer peripheral surface of the cartridge tube (100). The said inner tube (20) is telescopically slideable within the outer tube (10). The seal assembly (40) comprising of an oil seal and a dust seal is positioned in the recessed portion at the mouth of the outer tube (10) and outer peripheral surface of the inner tube (20).

[0031] Referring to Figs. 7a and 7b, in another embodiment of the adaptor bush (90’), the collar (95’) of the adaptor bush (90’) is configured to have a plurality rectangular slits (95S) on its outer peripheral edge. The number of the said rectangular slits (95S) are preferably provided with four slits for quick flow of oil inside the inner tube (20) while keeping the strength required for its functioning. However, the profile of the slits (95S) may be selected from the profile of circular, triangular, trapezoidal or combination thereof and the number of the said slits (95S) are not limited with four slits.

[0032] During the working, when the two wheeled vehicle is running on an uneven road surface, the fork will be compressed and decompressed. During the compression stroke, the inner tube (20) of the inverted front fork slides inside the outer tube (10). At this time, the main spring (70) gets compressed and the piston rod (110) along with the piston and rebound assembly (120, 140) slides inside the cartridge tube (100) which is filled with the working fluid. As the piston rod (110) along with the piston and rebound assembly (120, 140) slides inside the cartridge tube (100), it exerts pressure on the working fluid and therefore, the working fluid (oil) flows from the orifice (H) of the cartridge tube (100) to the chamber formed in the annular space between the inner tube (20) and the cartridge tube (100). At the same time, the working fluid will flow into the rebound chamber through the check valve of the piston assembly (120).

[0033] At the time of full compression of the fork, the conical body portion (92) of the adaptor bush (90, 90’) due to its taper angle (a) is configured to avoid the abutment of the inner diameter of the main spring (70) thereby eliminating the friction between the main spring (70) and the adaptor bush (90, 90’). Simultaneously, the spring guide (80) slides inside the central opening (90C) of the sintered adaptor bush (90, 90’), where the lower end (80L) of the spring guide (80) enters inside the central opening (90C) of the sintered adaptor bush (90, 90’) leading to the generation of a hydraulic lock in the first step portion (ST1) due to the stepped profile (SP) of the lower end (80L) of the spring guide (80) and this hydraulic lock creates the resistance to further movement of the spring guide (80) and thereby avoid the bottoming. Further, the O-ring (OR) which is provided inside the first step profile (ST1) of the central opening (90C) avoids the sudden impact between the lower end (80L) of the spring guide (80) and bottom face of the first step profile (ST1) so that a cushioning is created therein during the bottoming of the spring guide (80).

[0034] During the rebound stroke, the compressed main spring (70) is decompressed, and the working fluid flows inside the cartridge tube (100) through the orifice (H) of the cartridge tube from the inner tube (20) and through the check valve of the piston assembly (120) from the rebound chamber. The rebound spring of the rebound assembly (140), positioned between the adapter bush (90, 90’) and the piston assembly (120) provides the necessary cushioning to absorb the sudden jerk and prevent metal to metal contact of the adaptor bush (90, 90’) and the piston assembly (120).

[0035] The inverted front fork suspension of the present invention with the uniquely profiled adaptor bush (90, 90’) therein positioned intelligently at the mouth of the cartridge tube (100) impart following technical advantages that contribute to the technical advancement of the adaptor bush for inverted fork of a vehicle:
- The adaptor bush of the inverted fork of the present invention avoids the problem of rusting by making this part with sintered metal, such as steel.
- The adaptor bush of the inverted fork of the present invention has a conical portion for receiving the main spring so that the active coil of the spring will not be subjected for friction.
- The conical portion of the adaptor bush provides ease of sleeving of the spring over the adaptor bush.
- The adaptor bush of the inverted fork of the present invention, being made of sintered metal, improves the production efficiency and reduces the cost due to less material wastage and no machining required.
- The unique design of the adaptor bush of the inverted fork of the present invention and its positioning efficiently addresses the issue of the bottoming load and improve the consistency of the oil lock force.
- The unique design of the adaptor bush has rectangular slits on the collar, which allow the quick flow of oil from the inner tube to the main spring area, and also reduces the weight of the adaptor bush.

[0036] The foregoing description of the specific embodiment of the invention 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.
,CLAIMS:We Claim

1. An inverted fork suspension (1000) for a two wheeled vehicle comprises of an outer tube (10), an inner tube (20), a fork bolt (30), a seal assembly (40), a lock bolt (50), a bottom axle bracket (60), a main spring (70), a spring guide (80), an adaptor bush (90, 90’), a cartridge tube (100), a piston rod (110) with a piston assembly (120) and a rebound assembly (140), wherein
- the said adaptor bush (90, 90’) is configured to have a conical body portion (92) with central opening (90C), a cylindrical portion (96) and a collar (95, 95’); and said collar (95, 95’) is configured to project out in radial direction from the outer peripheral surface of a base portion (92B) of the conical portion (92);
- the base portion (92B) along with the collar (95, 95’) of the conical portion (92) is configured to merge with the cylindrical portion (96) to form a unitary structure of the adapter bush (90, 90’);
- the spring guide (80) has an upper end (80U), a lower end (80L) and a longitudinal central opening (80C); said lower end (80L) of the spring guide (80) has a step profile (SP) on the inner peripheral surface and said step profile (SP) is configured to create a clearance (C) with the piston rod (110);
- the main spring (70) is sleeved over the spring guide (80) and positioned in such a way that its upper end (E1) abuts with a set of spacers (S) in the outer tube (10) and its lower end (E2) rests over the collar (95, 95’) of the adaptor bush (90) in the inner tube (20) encircling the conical body portion (92) and maintaining the sufficient clearance between the main spring (70) and the body portion (92) of the adaptor bush (90, 90’);
- the cartridge tube (100), configured to accommodate the piston assembly (120) and the rebound assembly (140), is positioned over a base tab (BT) and is locked there by the press fitting;
- the inner tube (20) is concentrically sleeved over the cartridge tube (100) and is fitted with the axle bracket (60) by press fitting followed by welding and said inner tube (20) is telescopically slideable within the outer tube (10); and
- the seal assembly (40) comprising of an oil seal and a dust seal is positioned in the recessed portion at the mouth of the outer tube (10) and outer peripheral surface of the inner tube (20).

2. The inverted fork suspension (1000) for a two wheeled vehicle as claimed in claim 1, wherein
- the conical body portion (92) is configured to have ribs (94) running in axial direction on its outer peripheral surface and each of the ribs (94) is configured to have a lower portion (94L) and an upper portion (94U);
- the lower portion (94L) of the ribs (94) is formed from the top surface of the collar (95, 95’) and the upper portion (94U) is formed at the extreme end of the conical body portion (92) of the adapter bush (90, 90’);
- the width of the lower portion (94L) of the ribs (94) is greater than the width of the upper portion (94U) thereby making the trapezoidal cross sectional profile of the ribs (94); and
- said optimized trapezoidal profile of the ribs (94) is configured to reduce the weight of the adaptor bush (90, 90’) while keeping the mechanical properties of the adaptor bush (90, 90’) intact.

3. The inverted fork suspension (1000) for a two wheeled vehicle as claimed in claim 2, wherein
- the conical body portion (92) of the adaptor bush (90, 90’) at its base portion (92B), that merges with the collar (95, 95’), is configured to have outer diameter greater than the outer diameter of the extreme end thereby forming a conical profile of the body portion (92);
- said difference in outer diameters of the conical body portion (92) of the adaptor bush (90, 90’) forms a taper profile on the outer peripheral surface of the body portion (92) making a taper angle (a) with the vertical; and
- said taper angle (a) is configured to reduce the friction between the main spring (70) and body portion (92) of the adaptor bush (90. 90’) and varies from 3 degrees to 10 degrees.

4. The inverted fork suspension (1000) for a two wheeled vehicle as claimed in claim 3, wherein
- the adaptor bush (90, 90’) is configured to have the cylindrical portion (96) orthogonally projecting out in downward direction from the collar (95, 95’) and the outer peripheral surface of the cylindrical portion (96) has a circular groove (98); and
- said circular groove (98) is configured to get the adaptor bush (90, 90’) fitted with the open end of the cartridge tube (100) by spinning and grooving operation.

5. The inverted fork suspension (1000) for a two wheeled vehicle as claimed in claim 4, wherein
- the adaptor bush (90, 90’) has a thorough opening (90C) and said thorough opening (90C) is configured to form a multi-step profile (ST);
- the multi-step profile (ST) of the central opening (90C) of the adaptor bush (90, 90’) forms a first step profile (ST1) in the conical body portion (92) and said first step profile (ST1) is configured to receive the stepped end (80L) of the spring guide;
- the multi-step profile (ST) of the central opening (90C) of the adaptor bush (90, 90’) forms a second step profile (ST2) in the cylindrical body portion (96) and said second step profile (ST2) is configured to house the bush (BH) which is configured to control the friction and wear and tear of the piston rod (110);
- the multi-step profile (ST) of the central opening (90C) of the adaptor bush (90, 90’) forms a third step profile (ST3) in the cylindrical body portion (96) and said third step profile (ST3) is configured to guide the piston rod (110); and
- said first step profile (ST1) at its bottom end is configured to have a groove (90G) to receive an O-ring (OR) therein and said O-ring (OR) is made of rubber.

6. The inverted fork suspension (1000) for a two wheeled vehicle as claimed in claim 5, wherein
- the adaptor bush (90, 90’) is made of sintered metal selected from steel;
- said adaptor bush (90, 90’) is fitted with the cartridge tube (100) by the treaded joinery wherein the outer peripheral surface of the cylindrical body portion (96) of the adaptor bush (90, 90’) has threads instead of the circular groove (98) and said threads are configured to mesh with the threads provided on the inner peripheral surface of the cartridge tube (100) to have the positive locking of said adaptor bush (90, 90’) with the cartridge tube (100); and
- the optimized number of ribs (94) on the outer peripheral surface of the conical body portion (92) is four ribs (94).

7. The inverted fork suspension (1000) for a two wheeled vehicle as claimed in claim 6, wherein
- the adaptor bush (90’) has a collar (95’) and said collar (95’) of the adaptor bush (90’) is configured to have a plurality rectangular slits (95S) on its outer peripheral edge;
- the number of the said rectangular slits (95S) is four slits and said slits (95S) are configured to facilitate the quick flow of oil inside the inner tube (20) while keeping the strength intact required for its functioning; and
- the profile of the slits (95S) is selected from the profile of circular, triangular, trapezoidal or combination thereof.

8. The inverted fork suspension (1000) for a two wheeled vehicle as claimed in claim 6, wherein
- the cartridge tube (100) at its lower end is configured to have an orifice (H) above the base tab (BT) and said orifice (H) of the cartridge tube (100) is configured to allow the flow of fluid from the cartridge tube (100) to the inner tube (20) and vice-versa during working of the inverted front fork;
- the base tab (BT) is fitted with the bottom axle bracket (60) by using the lock bolt (50) through a threading mechanism;
- the piston rod (110) along with the piston assembly (120) and rebound assembly (140) is configured to slide within the cartridge tube (100) in downward and upward direction during the compression and rebound stroke, respectively; and
- said cartridge tube (100) is filled with the working fluid, preferably the oil.

9. The inverted fork suspension (1000) for a two wheeled vehicle as claimed in claim 8, wherein
- the piston rod (110) is fitted inside an opening (30T) of the fork bolt (30) by threaded joinery and said fork bolt (30) is configured to have a collar (30C) and an annular body (30A);
- the collar (30C) of the fork bolt (30) have a circular lug (30L) projected from the outer periphery of the collar (30C) in the direction of the annular body (30A) making a circular groove (30G) concentrically created in between the outer diameter of the annular body (30A) and inner diameter of the lug (30L);
- said circular groove (30G) is configured to receive a set of spacer (S) for pre-compression and said annular body (30A) has an opening (30T) for receiving an end of the piston rod (110);
- the spring guide (80) is sleeved over the piston rod (110) through the longitudinal central opening (80C) and said spring guide (80) has an upper end (80U) moulded with a lock nut (82), and said lock nut (82) is interlocked with the annular body (30A) of the fork bolt (30) by a threading mechanism; and
- the step profile (SP) of the spring guide (80) and the clearance (C) is configured to form an oil / hydraulic lock (HL) with the central opening (90C) of the adaptor bush (90) during the extreme compression stroke of the inverted fork (1000).

Dated this 19th day of Feb. 2025

(Sahastrarashmi Pund)
Head – IPR
Endurance Technologies Ltd.

To,
The Controller of Patents,
The Patent Office, at Mumbai