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
“FRONT FORK SUSPENSION SYSTEM FOR TWO AND THREE 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 damping assembly provided within front fork suspension of a motor vehicle. It more particularly relates to the damping spacers utilized in front fork assembly of a motor vehicle to provide enhanced damping performance when the level of damping fluid filled in the front fork is low.

Background of the Invention

[002] In front fork suspensions utilized on two and three wheeled motor vehicles, the seat pipe/tube, depending on the system architecture, may not be fully submerged in damping fluid, e.g. inverted front forks. This partially submerged/fully exposed condition of submergence of the seat pipe normally arises due to deliberate under filling of damping fluid that is undertaken to maintain the maximum working damping fluid pressure below a threshold damaging pressure that can be survived by the oil seals in normal operating conditions of the front fork suspension. The deliberate under filling of damping fluid can therefore enhance the life of oil seal and thereby prevent emergence of damping fluid leakages.

[003] The under filling of damping fluid in front fork suspension utilized in two and three wheeled motor vehicle creates situations in which the damping fluid does not reach the damping orifices provided on the seat pipe immediately when the compression of the front fork suspension is beginning. As such, when an under filled front fork suspension undergoes cycles of low amplitude compression and expansion at varying frequency, the damping force obtained from the seat pipe/tube may not even reach the ideal minimum magnitude needed for a stable and comfortable ride. Alternatively, an under filled front fork can also undergo cycles of high amplitude compression and expansion at varying frequencies and/or speed. In such an operating condition, sudden spikes in damping force magnitude are noticeable especially during compression of the front fork. These sudden spikes coincide with instant of time when damping fluid actually reaches and passes through the damping orifices given on the seat pipe/tube. Such sudden spikes in the damping force magnitude make riding of the two wheeled vehicle an extremely uncomfortable if not outrigtly unsafe experience for the rider. Given this factual scenario, a perfect balance has to be struck while deciding the level of damping fluid in a front fork suspension. As this balancing act can lead to less than idea front fork damping performance but allow enhancement in the life of the oil seal(s), there is an existing but unfulfilled requirement of a front fork suspension that can be under filled with damping fluid while also maintaining its damping performance.

Objectives of the Invention

[004] The main object of the present invention is to provide a front fork suspension that gives a consistently superior riding performance.

[005] Another object of the present invention is to provide a front fork suspension that imparts enhanced life to the suspension unit as compared to conventional solutions.

[006] Still another object of the present invention is to provide a front fork suspension in which oil seals and other sliding members are not damaged due to pressure exerted by the damping fluid.
[007] Yet another object of the present invention is to provide a front fork suspension in which spikes in damping force magnitudes are handled in a controlled manner during operation of the motor vehicle.

[008] Another objective of the present invention is to provide a front fork suspension that achieves the required minimum damping value for stable and comfortable operation of the motor vehicle.

[009] Further, the objective of the present invention is to provide suspension system that enables damping force performance viz. progressive, digressive, flat and combination of thereof, to meet vehicle dynamics and the road load conditions for superior vehicle handling, ride comfort and performance.

[0010] Yet, the objective of the present invention is to provide suspension system that enables damping force performance based on piston velocity and road input frequencies.

Brief Description of Drawings

[0011] This invention is illustrated in the accompanying drawings, throughout which like reference letters 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

[0012] Figure 1 shows a fully assembled front fork suspension in accordance with a preferred embodiment of the present invention.
[0013] Figure 2a shows cut section of a front fork in accordance with a first preferred embodiment of the present invention.

[0014] Figure 2b shows expanded section of a front fork in accordance with a first preferred embodiment of the present invention as shown in Fig. 2a.

[0015] Figure 2c and 2d show sections of a damping spacer and Figure 2e show a seat pipe as provided in a front fork in accordance with a first preferred embodiment of the present invention.

[0016] Figure 3a shows cut section of a front fork in accordance with a second preferred embodiment of the present invention.

[0017] Figure 3b shows expanded section of a front fork in accordance with a second preferred embodiment of the present invention as shown in Fig. 3a.

[0018] Figure 3c shows a cylindrical block, support base, shim(s) and nut as provided in a front fork in accordance with a second preferred embodiment of the present invention.

[0019] Figure 4a shows cut section of a front fork in accordance with a third preferred embodiment of the present invention.

[0020] Figure 4b shows expanded section of a front fork in accordance with a third preferred embodiment of the present invention as shown in Fig. 4a.
[0021] Figure 4c shows a cylindrical block, support base, shim(s) and nut as provided in a front fork in accordance with a third preferred embodiment of the present invention.

Detailed Description of the Present Invention

[0022] For the purpose of solving the mentioned issues the following front fork suspension for two and three wheeled motor vehicle having an improved damping assembly is hereby disclosed. The improved damping assembly of the front fork suspension comprises of at least an outer tube (10), a fork bolt (20), an O-ring (25), a seat pipe (30) and a damping spacer (40).

[0023] In the preferred embodiments and particularly in the first preferred embodiment of disclosed invention as shown in Figs 2a and 2b, the fork bolt (20) is mounted on an open end of the outer tube (10). An O-ring (25) is mounted in a groove on the outer surface of the fork bolt (20) so as to be situated between the fork bolt (20) and the outer tube (10). The seat pipe (30) along its first open end is mounted on the fork bolt (20) so as to be coaxial with and to be located within the outer tube (10). The seat pipe (30) has at least two set of damping orifices (30A and 30D) provided along two corresponding horizontal planes given at two different heights above the end of the seat pipe (30) mounted on the fork bolt (20). Additional damping orifices (30B and 30C) may also be provided along two other corresponding horizontal planes given at two different heights above the end of the seat pipe (30) mounted on the fork bolt (20) i.e. in addition to the orifices (30A and 30D) (refer Figs. 2a and 2e). The damping spacer (40) having the shape of a hollow cylinder, has three different outer diameter sections (42, 44 and 46) (refer Figs. 2b, 2c and 2d). The middle section (44) has the same inner diameter as the other end sections (42 and 46) but its outer diameter is lower than that of the other end sections (42 and 46). One of the end section (42) of the damping spacer (40) is mounted and fixed on the inside curved surface of the seat pipe (30) in a manner such that the middle section (44) is partially situated within the seat pipe (30) and partially outside of an open end of the seat pipe (30) formed by a piston head (32) and with the other end section (46) being situated completely outside the open end formed by the piston head (32). At least the other end section (46) that is situated completely outside the open end formed by the piston head (32) is always submerged in damping fluid inside the front fork suspension (100). Optionally, the middle section (44) of the damping spacer (40) is mounted on to the end section (42) of the damping spacer (40) by means of a mechanical joining means selected from threads, rivets, press fit, and combination thereof. The end section (42) on which the middle section (44) of the damping spacer (40) is mounted via a mechanical joint/s is itself mounted and fixed on the inside curved surface of the seat pipe (30).

[0024] In a second preferred embodiment of the front fork (100) with an improved damping assembly (refer Figs. 3a, 3b and 3c), in addition to the sub-components and their arrangement as detailed above, the seat pipe (30) provided in the front fork (100) has at least two set of damping orifice (30A and 30D) provided along two corresponding horizontal planes given at two different heights above the end of the seat pipe (30) mounted on the fork bolt (20). Additional damping orifices (30B and 30C) may also be provided along two other corresponding horizontal planes given at two different heights above the end of the seat pipe (30) mounted on the fork bolt (20) i.e. in addition to the orifices (30A and 30D). In this preferred embodiment, a hollow cylindrical block (50) is fitted on the end section (46) of the damping spacer (40) located completely outside the open end of the seat pipe (30) formed by the piston head (32). This hollow cylindrical block (50) has one flat outer surface (51) provided by a closed end (50C) of the hollow cylindrical block (50). This flat outer surface (51) provided by the closed end (50C) has one set of damping orifice (50A) provided from a first horizontal plane (X-X). Another set of damping orifice (50B) is provided from a second horizontal plane (Y-Y) that lies at a height below the first horizontal plane (X-X) when considered with reference to the one flat outer surface (51) of the closed end (50C) of the hollow cylindrical block (50).

[0025] The closed end (50C) of the cylindrical block (40) also has a central hole (50H) that accommodates a bolt (54). The head (54H) of the bolt (54) is located within the hollow cylindrical block (50). The lower surface of the head (54H) supports one end of a first conical spring (56) (that may also be a helical spring, Belleville spring or any other spring member) whereas the other end of the first conical spring (56) (that may also be a helical spring, Belleville spring or any other spring member) is supported on a first set of flexible shim(s) (58) that are in turn positioned above an inside flat surface of the hollow cylindrical block (50). The first set of flexible shim(s) or first plurality of shims (58) is configured so as to cover only the damping orifice (50B) from inside the hollow cylindrical block (50), while leaving the damping orifice (50A) open. The shaft (54S) of the bolt (54) extending outwards from the central hole (50H) supports and fixes a support base (60) in its position through a nut (62) mounted on the shaft (54S) above the support base (60). One surface of the support base (60) supports one end of a second conical spring (64) (that may also be a helical spring, Belleville spring or any other spring member) while the other end of this second conical spring (64) (that may also be a helical spring, Belleville spring or any other spring member) is supported on a second set of flexible shim(s) or second plurality of shims (66). The second set of flexible shim(s) or second plurality of shims (66) is so situated on the flat outer surface (51) of the closed end (50C) that they cover only the damping orifice (50A) while leaving the damping holes (50B) open. The orifices (50B and 50A) are provided at different radial distances from the central axis of the hollow cylindrical block (50), and hence the shims (58 and 66) have different inner and outer diameter to allow for them to cover only their respective orifices.

[0026] Additional damping orifices that not covered by any of set of flexible shim(s) or a plurality of shims may also be provided on the cylindrical portion of the hollow cylindrical block (50). The additional damping orifices would permit partially hindered flow of damping fluid, thereby enabling a reduction in the maximum value of damping force obtainable from the hollow cylindrical block (50) fitted on the damping spacer (40).

[0027] In a third preferred embodiment of the front fork (100) (refer Figs. 4a, 4b and 4c) with improved damping assembly, in addition to the sub-components and their arrangement as detailed for the first preferred embodiment, the seat pipe (30) is provided with at least two set of damping orifice (30A and 30D) provided along two corresponding horizontal planes given at two different heights above the end of the seat pipe (30) mounted on the fork bolt (20). Additional damping orifices (30B and 30C) may also be provided along two other corresponding horizontal planes given at two different heights above the end of the seat pipe (30) mounted on the fork bolt (20) i.e. in addition to the orifices (30A and 30D). A hollow cylindrical block (70) is fitted on the end section (46) of the damping spacer (40) located completely outside the open end of the seat pipe (30) formed by the piston head (32). This hollow cylindrical block (70) has a flat outer surface (71) provided by a closed end (70C) of the hollow cylindrical block (70). One set of damping orifice (70A) is provided from this flat outer surface (71) provided by the closed end (70C) of the hollow cylindrical block (70). The closed end (70C) of the cylindrical block (70) also has a central hole (70H) that accommodates a bolt (74). The head (74H) of this bolt (74) is located within the hollow cylindrical block (70). The lower surface of the head (74H) of this bolt (74) supports one end of a conical spring (76) (that may also be a helical spring, Belleville spring or any other spring member) whereas the other end of the conical spring (76) (that may also be a helical spring, Belleville spring or any other spring member) is supported on a set of flexible shim(s) or plurality of shims (78) that are in turn positioned above an inside flat surface (72) of the hollow cylindrical block (70). This set of flexible shim(s) or plurality of shims (78) is configured so as to cover the damping orifice (70A) provided from the flat outer surface (71) provided by the closed end (70C) of the hollow cylindrical block (70). The shaft of the bolt 74S) extending outwards from the central hole supports (70H) and fixes a support base (80) in its postion with the utilization of a nut (82). Another set of damping orifice (84) are provided from the curved surface of the hollow cylindrical block (70). Additional damping orifices that not covered by any of set of flexible shim(s) or plurality of shims may be provided on the hollow cylindrical block (70). The additional damping orifices would permit partially hindered flow of damping fluid, thereby enabling a reduction in the maximum value of damping force obtainable from the hollow cylindrical block (70) fitted on the damping spacer (40).

[0028] In all of the above embodiments of the front suspension system, the front fork (100) is of inverted fork type and/or is mounted in inverted arrangement wherein the outer tube (10) is positioned coaxially with the inner tube (90) so as to be in a telescopic association with said inner tube (90). A lower open end of the inner tube (90) is fitted with an axle mounting bracket (98). A main spring (102) is located within the inner tube (90) with its one end positioned on an upper surface of the piston head (32) of the seat pipe (30) and another end positioned on an upper surface of a spacer (104) that is positioned inside the inner tube (90) and located on a flat surface of the axle mounting bracket (98) within the inner tube (90) (refer Figs. 2a, 3a and 4a). A housing space (10S) given along the open end of outer tube (10) houses a guiding and sealing assembly (96) having at least a hollow cylindrical guide bush (96G), a washer (96W), an oil seal (96S), a circlip (96C) and a dust seal (96DS), mentioned in the order of their positioning within the housing space (10S).

[0029] In all of the embodiments of the front fork (100) with improved damping assembly (refer Figs. 2a, 3a and 4a), a rebound spring (106) is positioned inside the inner tube (10) with its one end resting upon lower surface of the piston head (32) given on the seat pipe (30) and another end resting upon a lower flat surface of a valve assembly (108). This valve assembly (108) is positioned and fixed within a housing space (90HS) given at an upper open end of the inner tube (90) by means of a cap (110) fitted at an upper open end of the inner tube (90) that is located within the outer tube (10). A bump rubber (92) is fitted on the outer curved surface of the seat pipe (30) by means of a circlip (94).

[0030] Again, in all of the embodiments of the front fork (100) with improved damping assembly, at least a single sliding bush (112) is mounted on the outer surface of the inner tube (90) so as to be positioned between the outer tube (10) and the inner tube (90) along the upper open end of the inner tube (10). The valve assembly (108) (refer Figs. 2b, 3b and 4b) positioned and fixed within the housing space (90HS) given at an upper open end of the inner tube (90) is provided with at least a valve block (108B), a conical spring (108CS) (that may also be a helical spring, Belleville spring or any other spring member) and a holder cup (108C) that are positioned in this order below the cap (110) fitted at the upper open end of the inner tube (90). The valve block (108B), the conical spring (108CS) (that may also be a helical spring, Belleville spring or any other spring member) and the holder cup (108C) that are positioned in this order below the cap (111) are located concentrically with the seat pipe (30) passing through the center of this valve assembly (108). A clearance may also provided between an inner curved surface of the cap (111) and the outer curved surface of the seat pipe (30). Another new embodiment may result from additional set of components being utilized in valve assembly (108) of the front fork suspension provided with/not provided with a damping spacer (40) or a damping spacer (40) with hollow cylindrical block (50, 70) as detailed for second and third embodiments.

[0031] When the motor vehicle wheel attached to the front fork suspension (100) (refer Fig. 1, 2a, 3a and 4a) passes over a road surface irregularity, the inner tube (90) moves within the outer tube (10) to cause compression of the main spring (102) that is located between the seat pipe (30) connected with the inner tube (90) and the spacer (104) given the closed end of the outer tube (10). This movement of the inner tube (90) within the outer tube (10) also causes the damping fluid to immediately begin flowing through the end section (46) of the damping spacer (40) that is located above the end of the seat pipe (30) formed by the piston head (32). In the embodiments where hollow cylindrical blocks (50, 70) are provided on the end section (46) of the damping spacer (40), the set of shim(s) or plurality of shims (58, 78) located within the hollow cylindrical block (50, 70) are deflected and/or displaced and the conical spring (56, 76) (that may also be a helical spring, Belleville spring or any other spring member) resisting there movement are compressed at this instant in time, thereby allowing some of the damping fluid to flow through the now partially opened damping orifices (50B, 70A) by deflecting/moving the shim(s) (58, 78). This immediately provides some damping force to resist compression of the front fork suspension (100). As the front fork suspension (100) continues to compress further, the damping fluid rises within the damping spacer (40) and then exits into the seat pipe (30) from where it proceeds to flow out through the damping orifices (30A and 30B as well, if provided) given at different heights on the seat pipe (30). Minor leakage of damping fluid also happens past the valve assembly (108) fitted in the housing space (90HS) and sliding interfaces given at the open end of inner tube (90) located within the outer tube (10). During compression, when the inner tube (90) is about to reach the closed/dead end of the outer tube (10), the bump rubber (92) fitted on the seat pipe (30) comes in contact with the cap (110) fitted at the upper open end of the inner tube (90) and causes it to deform and absorb the residual energy still remaining after compression of the main spring (102) up to that point. This act of compression of the bump rubber (92) stops any further movement of the inner tube (90) within the outer tube (10) of the front fork (100).

[0032] When the wheel of the motor vehicle has moved over this road surface irregularity the main spring (102) now starts expanding and releasing its stored energy. The energy that is now released is dissipated partially by the damping fluid flowing back through the orifices (30A and 30B as well, if provided) of the seat pipe (30) and then out via the damping spacer (40) fixed in the seat pipe (30). The damping fluid flowing past the valve assembly (108) fitted in the housing space (90HS) given at the open end of inner tube (90) located within the outer tube (10) also provides some of the required dissipation. This happens in all the embodiments (refer Figs. 2a, 3a and 4a) of the front fork (100) in accordance with the disclosed invention. The orifices (30D and 30C as well, if provided) also allow some of the damping fluid to flow and empty through them below the valve assembly (108) through them during this condition.

[0033] Specifically in the second embodiment, during expansion of the main spring (102), the conical spring (56) (that may also be a helical spring, Belleville spring or any other spring member) is compressed and the second set of shim(s) or second plurality of shims (66) is deflected by the damping fluid moving under pressure, which allows the damping fluid to flow through the damping orifices (50B) uncovered by deflection of the second set of shim(s) or second plurality of shims (66). The first set of shim(s) or first plurality of shims (58) given inside the hollow cylindrical block (50), which are smaller in dimension than the second set of shim(s) (66) given on the outside of the hollow cylindrical block (50), only partially cover the damping orifice (50A) that are covered completely by the second set of shim(s) or second plurality of shims (66) located on the outer flat surface (51) of the hollow cylindrical block (50). This setup allows the first set of shim(s) or first plurality of shims (58) to function along with the second set of shim(s) or second plurality of shims (66) during expansion of the front fork (100) to give more damping force than what would have been achieved by the second set of shim(s) or second plurality of shims (66) functioning by themselves. Additional damping orifices that not covered by any of set of flexible shim(s) or plurality of shims (if provided on the hollow cylindrical block) would also permit partially hindered flow of damping fluid, thereby enabling a reduction in the maximum value of damping force obtainable from the hollow cylindrical block (50) fitted on the damping spacer (40).

[0034] Specifically in the third embodiment, during expansion of the front fork suspension, the orifices (84) given through the curved surface of the hollow cylindrical block (70) allow the damping fluid flowing back out of the damping spacer (40) to exit into the outer tube (10), thereby dissipating a portion of the energy being released by expansion of the main spring (102). The hollow cylindrical block (70) in the third embodiment does not have a second set of shim(s) or second plurality of shims nor its associated second spring member/conical spring/Belleville spring/helical spring. Additional damping orifices that not covered by any of set of flexible shim(s) or plurality of shims (if provided on the hollow cylindrical block(70)) would also permit partially hindered flow of damping fluid, thereby enabling a reduction in the maximum value of damping force obtainable from the hollow cylindrical block (70) fitted on the damping spacer (40).

[0035] In all the embodiments as discussed above, the provision of damping spacer (40) enables partial filling of the front fork (100) without degradation its damping performance which thereby also prevents the maximum damping fluid pressure from exceeding the maximum survivable operating pressure of the oil seal provided in the front fork (100). The component of front fork suspension (100), which are the damping spacer (40) and the hollow cylindrical block (50, 70) and/or the valve assembly (108) fitted in the housing space (90HS) given at the open end of the inner tube (90) situated within the outer tube (10), allow a less steep, a flatter, a progressive, a digressive or any desired curve based on vehicle dynamics (or any combination thereof) damping curve to be achieved thereby improving rider comfort during low amplitude oscillation cycles, as well as high amplitude oscillation cycles considered at different oscillation frequencies and speed.

[0036] The front fork (100) having an improved damping assembly as disclosed provides the following technical advantages-
- The front fork suspension gives a consistently good riding performance in all operating conditions.
- As the likelihood of oil seal damage due to over filling of damping fluid is eliminated, the life of the front fork is enhanced.
- As spikes in damping force magnitude that may emerge during operation of an under filled front fork are controlled to meet performance, ride comfort and enhanced vehicle handling.
- The front fork suspension, under filled with damping fluid, also achieves the required minimum damping value for stable and comfortable operation of the motor vehicle during low amplitude oscillation cycles of the front fork suspension.
- The front fork suspension allows flexibility to select a less steep, a flatter, a progressive, a digressive, any desired damping curve (or any combination thereof) based on vehicle dynamics thereby improving ride comfort during low amplitude oscillation cycles, as well as high amplitude oscillation cycles considered at different oscillation frequencies.
- Overall operating temperature of the front fork suspension system is reduced resulting in improved working life.

[0037] While attempt has been made to describe the construction and working of the invention to the fullest possible extent, minor changes that do not detract from the outline established in this document are still possible. Such changes may pertain to the type of springs used, the valve assembly or the number of orifices provided on the seat pipe. Such changes can be considered as obvious to a person skilled in the art and must hence not be viewed to be taking any front fork with all the other features as covered by this description outside the scope of the claims of this specification.

[0038] 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. A front fork suspension (100) for two wheeled motor vehicle having an improved damping assembly (150), with the improved damping assembly (150) comprising of an outer tube (10), a fork bolt (20), an O-ring (25), a seat pipe (30), and a damping spacer (40),
wherein,
- the fork bolt (20) is mounted on an open end of the outer tube (10);
- an O-ring (25) is mounted in a groove on the outer surface of the fork bolt (20) so as to be situated between the fork bolt (20) and the outer tube (20);
- the seat pipe (30) along its one open end is mounted on the fork bolt (20) so as to be coaxial with and to be located within the outer tube (10);
- the damping spacer (40) having the shape of a hollow cylinder has three outer diameter sections (42, 44 and 46), the section (44) is situated between section (42 and 46) and has the same inner diameter as the sections (42 and 46) but lower outer diameter than sections (42 and 46), the section (42) of the damping spacer (40) is mounted and fixed on the inside curved surface of the seat pipe (30) in a manner such that the section (44) is partially situated within the seat pipe (30) and partially outside of an open end of the seat pipe (30) formed by a piston head (32) and with section (46) being situated completely outside the open end formed by the piston head (32); and
- the seat pipe (30) has at least two set of damping orifice (30A and 30D) provided along two corresponding horizontal planes given at two different heights above the end of the seat pipe (30) mounted on the fork bolt (20).

2. The front fork suspension (100) for two wheeled motor vehicle as claimed in claim 1, wherein a hollow cylindrical block (50) is fitted on the section (46) of the damping spacer (40), the hollow cylindrical block (50) has an outer surface (51) having one set of damping orifice (50A) provided along a horizontal plane (X-X) and another set of damping orifice (50B) provided along another horizontal plane (Y-Y) at a height above a closed end (50C) when considered with reference to the horizontal plane (X-X) of the hollow cylindrical block (50), the closed end (50C) of the cylindrical block also has a central hole (50H) that accommodated a bolt (54), the head (54H) of the bolt (54) is located within the hollow cylindrical block (50), the lower surface of the head (54H) supports one end of a conical spring (56) whereas the other end of the conical spring (56) is supported on flexible shim(s) (58) that are in turn positioned above an inside flat surface (52) of the hollow cylindrical block (50), the flexible shim(s) (58) is configured so as to cover only the damping orifice (50B) while leaving the openings of the damping orifice (50A) open, the shaft (54S) of the bolt (54) extending outwards from the central hole (50H) supports and fixes a support base (60) in its position through a nut (62) mounted on the shaft (54S) above the support base (60), one surface of the support base (60) supports one end of another conical spring (64) while the other end of this conical spring (64) is supported on flexible shims (66) positioned on the horizontal plane (Y-Y), the flexible shim(s) (66) so situated on the horizontal plane (Y-Y) cover only the damping orifice (50A) while leaving the holes corresponding to the damping orifice (50B) open.

3. The front fork suspension (100) for two wheeled motor vehicle as claimed in claim 1, wherein
- a hollow cylindrical block (70) is fitted on the section (46) of the damping spacer (40), the hollow cylindrical block (70) has an outer surface (71) having one set of damping orifice (70A) provided on a closed end (70C) of the hollow cylindrical block (70), the closed end (70C) of the cylindrical block also has a central hole (70H) that accommodated a bolt (74), the head (74H) of the bolt (74) is located within the hollow cylindrical block (70), the lower surface of the head (74H) supports one end of a conical spring (76) whereas the other end of the conical spring (76) is supported on flexible shim(s) (78) that are in turn positioned above an inside flat surface (72) of the hollow cylindrical block (70), the flexible shim(s) (78) are configured so as to cover the damping orifice (70A), the shaft (74S) of the bolt (74) extending outwards from the central hole (70H) supports and fixes a support base (80) in its postion with the utilization of a nut (82); and
- a plurality of damping orifice (84) are provided on the curved surface of the hollow cylindrical block (70).

4. The inverted front fork suspension (100) for two wheeled motor vehicle as claimed in any of the preceding claims, wherein section (44) of the damping spacer (40) is mounted on to the section (42) of the damping spacer (40) by means of a mechanical joining means selected from a threaded joint rivets, press fit, and combination thereof.

5. The front fork suspension (100) for two wheeled motor vehicle as claimed in any of the preceding claims, wherein,
- the outer tube (10) is positioned coaxially with the inner tube (90) so as to be in a telescopic association with said inner tube (90);
- a lower open end of the inner tube (90) is fitted with an axle mounting bracket (98);
- a main spring (102) is located within the inner tube (90) with its one end positioned on an upper surface of the piston head (32) of the seat pipe (30) and another end positioned on an upper surface of a spacer (104) that is positioned inside the inner tube (90) and located on a flat surface of the axle mounting bracket (98) within the inner tube (90);
- a housing space (10S) given along the open end of outer tube (10) houses a guiding and sealing assembly (96) having at least a hollow cylindrical guide bush (96G), a washer (96W), an oil seal (96S), a circlip (96C) and a dust seal (96DS), mentioned in the order of their positioning within the housing space (10S);
- a rebound spring (106) is positioned inside the inner tube (90) with its one end resting upon lower surface of the piston head (32) of the seat pipe (30) and another end resting upon a lower flat surface of a valve assembly (108), said valve assembly (108) is positioned and fixed within a housing space (90HS) given at an upper open end of the inner tube (90) by means of a cap (110) fitted at the upper open end of the inner tube (90) located within the outer tube (10); and
- a bump rubber (92) is fitted on the outer curved surface of the seat pipe (30) by a circlip (94).

6. The front fork suspension (100) for two wheeled motor vehicle as claimed in claim 5, wherein,
- a sliding bush (112) is mounted on the outer surface of the inner tube (90) so as to be positioned between the outer tube (10) and the inner tube (90) along the upper open end of the inner tube (90); and
- the valve assembly (108) has a block (108B), a conical spring (108CS) and a holder cup (108C) that are positioned in this order below the cap (110) and located concentrically with the seat pipe (30) passing through the center of this valve assembly (108), a clearance is also provided between an inner curved surface of the cap (110) and the outer curved surface of the seat pipe (30).

Dated this 24th day of Mar. 2023

Sahastrarashmi Pund
Head – IPR
Endurance Technologies Ltd.

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