DESC:TECHNICAL FIELD
[001] The present invention relates to a two-wheeler motorcycle’s suspension accessories and specifically, the present invention relates to the bolt cap assembly of the conventional telescopic front fork and inverted front fork which provides options for spring preload adjustment and damping adjustment mechanism.
BACKGROUND ART
[002] Motorcycle manufacturers are striving to offer a more comfortable riding experience to the rider, may it be a two-wheeler scooter, motorcycle, or bicycle. Currently, the two-wheelers come with a front suspension, which has a spring to absorb shocks caused by disturbances from the road, and a damper mechanism for the controlled energy dissipation from the spring.
[003] One such conventional front fork is disclosed in IN202121037537. The preload adjuster of this invention comprises of a top cap, a gear, an adjuster screw, an O-ring, a fork bolt, an O-ring, 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 preload adjuster provides accurate reading of the extent of pre-compression/preload already provided to the main spring of each fork leg of the front fork on which it is installed even beyond one complete rotation of the adjuster screw. The preload adjuster also prevents over rotation of the adjuster screw and hence over compression of the main spring of the front fork suspension. However, this assembly does not provide damping adjustment. Furthermore, this assembly includes many elements for adjusting preload.
[004] Along with the rider, when the vehicle is loaded with a pillion or luggage, the ride height of the vehicle will change as per the added load. The spring preload needs to be changed as per the varying ride height. However, this cannot be achieved without disassembling the conventional front fork. Similar to this, the damping of the fork is tuned with a change of oil viscosity and valve tuning by performing fork disassembly.
[005] To provide a mechanism for spring preload adjustment and damping adjustment as per the rider's needs, without performing the disassembly of the front suspension, motorcycle manufacturers came up with preload and damping adjustment mechanisms incorporated in the bolt cap of the inverted and conventional telescopic front forks.
[006] Accordingly, there exists a need for a compact mechanism for both, spring preload and damping adjustment that can be used as a stand-alone mechanism and can be easily incorporated into existing front forks as a retrofit kit.
OBJECT OF THE INVENTION
[007] An object of the present invention is to provide an integrated mechanism for spring preload adjustment and damping adjustment for conventional and inverted front forks in two-wheelers.
[008] Another object of the present invention is to provide a mechanism that can be used as a retrofit kit in an existing conventional front fork and inverted front fork.
[009] Another object of the present invention is to provide a mechanism that deploys fewer moving parts to carry out the adjustments.
[0010] Another object of the present invention is to provide a cost-effective mechanism for spring preload adjustment and damping adjustment.
[0011] Another object of the present invention is to provide a bolt cap for a two-wheeler front fork which can be assembled with the help of a circlip.
[0012] Another object of the present invention is to provide a floating spring seater for proper seating of a spring to prevent the misalignment of components.
[0013] Another object of the present invention is to provide the spring preload adjustment and damping adjustment that can be operated independently without disturbing one another.
SUMMARY OF THE INVENTION
[0014] The present invention provides a front fork bolt cap with integrated spring preload and damping adjustment. The spring preload adjuster mechanism comprises an adjuster screw at its one end connected to a bolt cap using a circlip and its other end connected to a spring, a slider part that is secured inside the bolt cap using a circlip. The bolt cap having at least one profiled groove at the inner diameter. The slider part having at least one profile cut at the outer diameter thereof, wherein the groove and the profile cut facilitate the surface contact of the slider part with the bolt cap. The clockwise rotation of the adjuster screw results in downward movement of the slider part causing compression of the spring. The anticlockwise rotation of the adjuster screw results in upward movement of the slider part, causing a release in load on the spring. The upward and downward movement of the slider part is restricted by an extruded circular profile of the adjuster screw and a circlip respectively.
[0015] The damping adjustment mechanism comprises a damping adjuster connected to a shaft and assembled inside the adjuster screw with a sealant. The clockwise rotation of the damping adjuster resulting in the downward movement thereof which causes the shaft to vary the oil flow in a piston assembly of the front fork providing high damping forces. The anticlockwise rotation of the damping adjuster resulting in the upward movement thereof which causes the shaft to vary the oil flow in a piston assembly of the front fork providing low damping forces.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The objects and advantages of the present invention will become apparent when the disclosure is read in conjunction with the following figures, wherein
[0017] Figure 1(a) represents a sectional view of a spring preload adjustment mechanism (100) with a threaded bolt cap in accordance with an embodiment of the present invention,
[0018] Figure 1(b) represents a sectional view of a spring preload adjustment mechanism (100) with a circlip bolt cap in accordance with an embodiment of the present invention,
[0019] Figure 2(a) represents a sectional view of a spring preload adjustment mechanism (100) emphasizing the slider part and bolt cap interface in accordance with an embodiment of the present invention,
[0020] Figure 2(b) represents an exploded view of the slider part and bolt cap interface in accordance with an embodiment of the present invention,
[0021] Figure 3(a) and Figure 3(b) shows the working of a spring preload adjustment mechanism (100) representing the clockwise and anticlockwise rotation of the adjuster screw respectively in accordance with an embodiment of the present invention,
[0022] Figure 4(a) represents the integrated spring preload adjustment mechanism with a damping adjustment mechanism for a threaded bolt cap in accordance with an embodiment of the present invention,
[0023] Figure 4(b) represents the integrated spring preload adjustment mechanism with a damping adjustment mechanism for a circlip bolt cap in accordance with an embodiment of the present invention, and
[0024] Figure 5 shows the working of the integrated spring preload adjustment and the damping adjustment mechanism (200) using a screw driver in accordance with an embodiment of the present invention.
[0025] It should be appreciated by those skilled in the art that any schematic diagrams herein represent conceptual views of illustrative systems embodying the principles of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0026] The embodiments herein provide a front fork bolt cap with integrated spring preload adjustment and damping adjustment for two-wheelers.
[0027] Throughout this application, with respect to all reasonable derivatives of such terms, and unless otherwise specified (and/or unless the particular context clearly dictates otherwise), each usage of:
“a” or “an” is meant to read as “at least one.”
“the” is meant to be read as “the at least one.”
[0028] References in the specification to “one embodiment” or “an embodiment” mean that a particular feature, structure, characteristic, or function described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.
[0029] Hereinafter, embodiments will be described in detail. For clarity of the description, known constructions and functions will be omitted.
[0030] The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in brackets in the following description.
[0031] In one of the exemplary embodiments of the present invention, a mechanism for spring preload adjustment and damping adjustment may be installed in a telescopic front fork and an inverted front fork of a two-wheeler as a retrofit kit.
[0032] In one of the exemplary embodiments of the present invention, a mechanism for spring preload adjustment and damping adjustment can be installed in the inner tube in the conventional front fork and the outer tube in the inverted front fork.
[0033] In one of the exemplary embodiments of the present invention, the spring preload adjustment and the damping adjustment can be achieved independently without disturbing one another.
[0034] In an exemplary embodiment, the present invention provides a spring preload adjustment mechanism (100). The spring preload adjustment mechanism (100) comprising an adjuster screw (101) at its one end connected to a bolt cap (103) with a sealant (104) by using a circlip (102) and its other end connected to the spring (109). The bolt cap (103) is fitted by a threaded interface or circlip to the front fork. The spring preload adjustment mechanism (100) further comprises a slider part (105) that is secured inside the bolt cap (103) and connected to the adjuster screw (101), and a circlip (107). The rotation of the adjuster screw (101) causing movement of the slider part (105), which facilitates in preload adjustment in accordance with the direction of the rotation thereof.
[0035] In another exemplary embodiment, the present invention provides an integrated spring preload adjustment with damping adjustment mechanism (200). The integrated spring preload adjustment with damping adjustment mechanism (200) comprises a damping adjuster (111) provided in the adjuster screw (101) connected to a shaft (112).
[0036] In an implementation of one of the exemplary embodiments of the present invention, the construction of the spring preload adjustment mechanism (100) is explained by referring to Figure 1(a). In one of the exemplary embodiments of the present invention, the adjuster screw (101) having least two grooves (11) to assemble at least two circlips (102, 107) therein, an extruded circular profile (12) configured to maintain surface contact with the bolt cap (103). The circlip (102) is provided at one end to secure the adjuster screw (101) in position and the circlip (107) is positioned at the other end of the adjuster screw (101). The circlip (102) is configured to restrict the downward movement of the adjuster screw (101). The adjuster screw (101) with a sealant (104) is assembled at the first end with a bolt cap (103) by using a circlip (102). In an exemplary embodiment of the invention, the sealant (104) may be an O-ring or a Quad ring.
[0037] In one of the exemplary embodiments of the present invention, the slider part (105) includes a specific profile cut (14) provided at the outer diameter thereof. In one of the exemplary embodiments of the present invention, the bolt cap (103) is provided with a specific profile groove (13) at the inner diameter. The slider part (105), at its one end, is connected with the adjuster screw (101) by means of a thread interface and made to have profile contact with the internal diameter of the bolt cap (103) by means of the special profile cut (14). The slider part (105), at the other end, is connected to the spring (109) via a spring seat (108) and a spacer (106). The circlip (107) is configured to restrict the downward movement of the slider part and to act as a preload adjustment stopper.
[0038] In an exemplary embodiment of the invention, the spring seat (108) is provided to make contact with the front fork spring (109). In another exemplary embodiment of the invention, the spring seat (108) and the spacer (106) can be integrated as a single part that may be plastic molded, or machined, or forged. Alternatively, the spring seat (108) and the spacer (106) can be formed as distinct parts and placed as a floating assembly.
[0039] The bolt cap (103) is configured with the special profiled groove (13) at the inner diameter. The slider part (105) is designed with the profile cut (14) at the outer diameter thereof. The groove (13) and the profile cut (14) facilitate the surface contact of the slider part (105) with the bolt cap (103). Additionally, the bolt cap (103) is configured to have a circular groove (15) for a circlip (110) to assemble with the inner tube of the conventional front fork or outer tube of the inverted front fork.
[0040] In an exemplary embodiment, when the adjuster screw (101) is rotated in a clockwise direction, it results in a corresponding movement of the slider part (105). According to an exemplary embodiment of the invention, the rotation of the adjuster screw (101) is converted into the linear downward movement of the slider part (105) due to the guiding of slider part inside the bolt cap groove, which compresses the spring (109) further. Once the targeted pre-compression length is achieved, the linear displacement of the slider part is stopped by the circlip (107) at the adjuster screw end.
[0041] Referring to Figure 3(b), an anticlockwise rotation of the adjuster screw (101) results in upward movement of the slider part (105). This movement causes a release in load on the spring (109). Once the spring (109) preload is released completely, the linear displacement of the slider part (105) is stopped by the surface contact between the adjuster screw (101) and slider part (105).
[0042] In an implementation of one of the exemplary embodiments of the present invention, the construction of the integrated damping adjustment mechanism (200) for a threaded bolt cap (103) is explained by referring to Figure 4(a). The integrated spring preload and damping adjustment mechanism (200) comprises the spring preload adjustment mechanism (100), a damping adjuster (111), a shaft (112), and a stopper (114). In an exemplary embodiment, the adjuster screw (101) has a hollow passage at center to accommodate the damping adjuster (111) therein. The damping adjuster (111) is assembled inside the adjuster screw (101) with a sealant (113) to prevent any leakages from the front fork. The damping adjuster (111) is operably coupled to the shaft (112) at one end by means of a threaded interface. The other end of the shaft (112) is connected to the piston assembly of the front fork which has the damping adjustment. The stopper (114) is configured to be press-fitted on the adjuster screw (101) and restricts the upward movement of the damping adjuster (111).

[0043] Referring to Figure 5, when the damping adjuster (111) is rotated in a clockwise direction, with the help of the thread interface between the damping adjuster (111) and adjuster screw (101), the damping adjuster (111) starts to move in a downward direction. The downward movement of the damping adjuster (111) causes the shaft (112) to vary the oil flow in the piston assembly. This causes the front fork to provide high damping forces. Further downward movement of the damping adjuster (111) is restricted by the surface contact between damping adjuster (111) and adjuster screw (101) at point (A) shown in fig.4(b). When damping adjuster (111) is rotated in anti-clockwise direction, with the help of a threaded interface between the damping adjuster (111) and the adjuster screw (101), the damping adjuster starts to move in an upward direction. The shaft (112) connected with the damping adjuster (111) starts to vary the oil flow in the piston assembly, due to which the front fork is adjusted to provide low damping forces. Further upward movement of the damping adjuster (111) is restricted by the surface contact between the damping adjuster (111) and the stopper (114). In an exemplary embodiment, the rotation of the the damping adjuster (111) is achieved using a screw driver, and any relevant tool.
ADVANTAGES OF THE INVENTION
1. Front fork bolt cap with integrated spring preload and damping adjustment offers a compact and cost-effective mechanism with fewer moving parts to carry out the adjustments.
2. The present invention is provided for use as a retrofit kit in an existing conventional front fork and inverted front fork assembly.
3. The present invention offers a low-cost bolt cap solution with a circlip that allows faster assembly of components.
4. The present invention offers a low-cost spring seater with a spacer that provides the proper seating for the spring.
5. Both, the spring preload adjustment and the damping adjustment can be operated independently without disturbing one another’s functionality.
6. The present invention provides an assembly which requires less assembly time and cost as compared to the conventional one.

[0044] The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the scope of the present invention.
,CLAIMS:We claim:
1. A front fork bolt cap with spring preload adjustment mechanism (100) for two-wheelers, the spring preload adjustment mechanism (100) comprising
an adjuster screw (101) connected to a bolt cap (103) at its one end and to a spring (109) at its other end;
a slider part (105) secured inside the bolt cap (103) and connected to the adjuster screw (101); and
at least two circlips (102, 107) to secure the adjuster screw (101) in position,
wherein, the adjuster screw (101) having
at least two grooves (11) to assemble at least two circlips (102, 107) therein, and
an extruded circular profile (12) configured to maintain surface contact with the bolt cap (103);
the bolt cap (103) having at least one profiled groove (13) at the inner diameter,
the slider part (105) having at least one profile cut (14) at the outer diameter thereof, wherein the profiled groove (13) and the profile cut (14) facilitate the surface contact of the slider part (105) with the bolt cap (103);
wherein, the clockwise rotation of the adjuster screw (101) results in downward movement of the slider part (105) causing compression of the spring (109);
wherein, the anticlockwise rotation of the adjuster screw (101) results in upward movement of the slider part (105), causing a release in load on the spring (109).

2. The front fork bolt cap with spring preload adjustment mechanism (100) as claimed in claim 1, wherein a sealant (104) is used to assemble the adjuster screw (101) with the bolt cap (103) at the first end.
3. The front fork bolt cap with spring preload adjustment mechanism (100) as claimed in claim 1, wherein the circlip (102) is positioned at one end to secure the adjuster screw (101) in position and restrict any downward movement thereof.

4. The front fork bolt cap with spring preload adjustment mechanism (100) as claimed in claim 1, wherein the extruded circular profile (12) is configured to restrict the upward movement of the adjuster screw (101) upon contact with the bolt cap (103).

5. The front fork bolt cap with spring preload adjustment mechanism (100) as claimed in claim 1, wherein the circlip (107) is positioned at the other end of the adjuster screw (101) to restrict the downward movement of the slider part (105) and to act as a preload adjustment stopper.

6. The front fork bolt cap with spring preload adjustment mechanism (100) as claimed in claim 1, wherein the slider part (105), at its one end, is connected with the adjuster screw (101) by means of a thread interface.

7. The front fork bolt cap with spring preload adjustment mechanism (100) as claimed in claim 1, wherein the slider part (105), at its other end, is connected to the spring (109) via a spring seat (108) and a spacer (106), wherein the spring seat (108) is provided to make contact with the front fork spring (109).

8. The front fork bolt cap with spring preload adjustment mechanism (100) as claimed in claim 1, wherein the bolt cap (103) further includes a circular groove (15) for a circlip (110) to assemble with an inner tube of the front fork or an outer tube of the inverted front fork.

9. A front fork bolt cap with integrated spring preload and damping adjustment mechanism (200) for two-wheelers, the integrated spring preload and damping adjustment mechanism (200) comprising
an adjuster screw (101) connected to a bolt cap (103) at its one end and to a spring (109) at its other end;
a slider part (105) secured inside the bolt cap (103) and connected to the adjuster screw (101); and
at least two circlips (102, 107) to secure the adjuster screw (101) in position,
wherein, the adjuster screw (101) having
at least two grooves (11) to assemble at least two circlips (102, 107) therein,
an extruded circular profile (12) configured to maintain surface contact with the bolt cap (103), and
a hollow passage at center therethrough;
the bolt cap (103) having at least one profiled groove (13) at the inner diameter;
the slid er part (105) having at least one profile cut (14) at the outer diameter thereof, wherein the groove (13) and the profile cut (14) facilitate the surface contact of the slider part (105) with the bolt cap (103);
a damping adjuster (111) assembled inside the adjuster screw (101);
a shaft (112) operably coupled to the damping adjuster (111) at one end and to the piston assembly of the front fork at another end; and
a stopper (114) configured to be press-fitted on the adjuster screw (101) and restricts the upward movement of the damping adjuster (111),
wherein, the clockwise rotation of the damping adjuster (111) resulting in the downward movement thereof which causes the shaft (112) to vary the oil flow in a piston assembly of the front fork providing high damping forces;
wherein, the anticlockwise rotation of the damping adjuster (111) resulting in the upward movement thereof which causes the shaft (112) to vary the oil flow in a piston assembly of the front fork providing low damping forces.

10. The front fork bolt cap with integrated spring preload and damping adjustment mechanism (200) as claimed in claim 9, wherein the damping adjuster (111) is assembled inside the adjuster screw (101) by means of a thread interface and a sealant (113) therebetween to prevent any leakages from the front fork.

Dated this on 19th day of December 2024

Prafulla Wange
(Agent for Applicant)
(IN/PA: 2058)