DESC:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2005
COMPLETE SPECIFICATION
(See section 10, rule 13)
1. TITLE OF THE INVENTION:
ADJUSTABLE HIGH-VELOCITY BLOW-OFF VALVE ASSEMBLY FOR TELESCOPIC FRONT FORK
2. APPLICANT
(a) Name: Gabriel India Ltd.
(b) Nationality: An Indian Company
(c) Address:
29th Milestone, Pune – Nashik highway, Village Kuruli, Tal. Khed, Maharashtra 410501. India
3. PREAMBLE TO THE DESCRIPTION
PROVISIONAL
The following specification describes the invention. COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
The present invention relates to the suspension mechanism in vehicles and specifically, the present invention relates to an adjustable high-velocity blow-off valve assembly for the telescopic front fork deployed in two-wheelers.
BACKGROUND ART
The suspension mechanism plays a vital role in vehicles. It provides comfort and a cushioning effect during driving, especially in situations when the terrain is imperfect with bumps or dips. Moreover, it contributes while braking and maintains the contact between the tires and the ground.
A few major issues with the existing suspension mechanism are the rough crossing of sharp-edged bumps at high velocities, compromised steering response in cornering, and the requirement of disassembling the front fork for the tuning of damping for different velocities. Changing oil viscosity can aid in control of the rebound damping to some extent. Still, it changes the compression damping as well and that has to be adjusted independently.
A digressive valve is used to overcome the above-stated issues in the conventional front fork. The digressive valve ensures independent tuning of compression and rebound damping. Additionally, it yields a digressive compression damping curve and provides a little help in controlling the rebound damping. The prior art such as the digressive valve requires the disassembling of the front fork for tuning the damping for different velocities.
Accordingly, there exists a need for an improved suspension mechanism that facilitates tuning of low-velocity and high-velocity compression damping without disassembling the conventional front fork, smooth crossing of sharp-edged bumps at high velocities, and improved steering response in cornering.
SUMMARY OF THE INVENTION
This section is provided to introduce certain objects and aspects of the present disclosure in a simplified form that are further described below in the detailed description. This summary is not intended to identify the key features or the scope of the claimed subject matter.
The present disclosure generally relates to suspension mechanism in vehicles and specifically, the present invention relates to an adjustable high-velocity blow-off valve assembly for the telescopic front fork. The adjustable high-velocity blow-off valve assembly for a telescopic front fork includes a plunger and a valve stem assembled inside a valve casing. The assembly includes a circlip assembled on the valve stem groove, configured to lock the valve stem with the valve casing. The assembly includes a compression spring assembled between a spring seater and the plunger. The assembly includes a non-return valve with a rebound spring seated on a valve cap. The assembly includes a blow-off valve configured with a plurality of bleed holes and a plurality of grooves and torqued with the valve cap. The assembly includes a plurality of balls configured to get accommodated inside the plurality of grooves in the blow-off valve. The valve casing is fitted with a dog-point screw that facilitates to convert the rotation of the valve stem to the linear motion of the plunger to vary the preload of the compression spring.
OBJECT OF THE INVENTION
An object of the present invention is to provide an adjustable high-velocity blow-off valve assembly (hereinafter referred to as “assembly (100)” or “blow-off valve assembly (100)”) for a telescopic front fork as a retrofit arrangement to achieve digressive compression damping.
Yet another object of the present invention is to provide an assembly for tuning low-velocity and high-velocity compression damping in a telescopic front fork.
Yet another object of the present invention is to provide the assembly to facilitate damping adjustment with the blow-off valve for different velocities in the telescopic front fork.
Still another object of the present invention is to provide the assembly, the placement of which ensures proper seating of the main coil spring in a telescopic front fork.
BRIEF DESCRIPTION OF THE DRAWINGS
The objects and advantages of the present invention will become apparent when the disclosure is read in conjunction with the following figures, wherein
Figure 1(a) illustrates a sectional view of the adjustable high-velocity blow-off valve assembly (100), in accordance with an embodiment of the present invention where a coil spring is used on the rebound side;
Figure 1(b) illustrates a sectional view of the assembly (100), in accordance with an embodiment of the present invention where a leaf spring is used on the rebound side;
Figure 2 represents the exploded view (200) of the assembly (100) in accordance with an embodiment of the present invention;
Figure 3 represents the schematic representation of the preload adjuster (300) for the blow-off valve (107) in accordance with an embodiment of the present invention, wherein,
Figure 3(a) represents the exploded view of the preload adjuster screw assembly (300-a) in accordance with an embodiment of the present invention;
Figure 3(b) represents the exploded view of the preload adjuster rod interface (300-b) in accordance with an embodiment of the present invention;
Figure 3(c) represents the exploded view of the blow-off valve (107) interface in accordance with an embodiment of the present invention;
Figure 4 represents the position-dependent perspective of the blow-off valve assembly (100), the preload adjuster screw assembly (300-a), and the preload adjuster rod interface (300-b) with respect to the front fork (400) in accordance with an embodiment of the present invention;
Figure 5(a) represents the schematic depicting the functional aspect of the blow-off valve assembly (100) on low and medium compression velocities in accordance with an embodiment of the present invention;
Figure 5(b) represents the schematic depicting the functional aspect of the blow-off valve assembly (100) on high compression velocities in accordance with an embodiment of the present invention;
Figure 5(c) represents the schematic depicting the functional aspect of the blow-off valve assembly (100) on rebound stroke in accordance with an embodiment of the present invention;
Figure 6(a) and 6(b) represent the schematic of the preload adjustment for the blow-off valve in accordance with an embodiment of the present invention;
Figure 7 represents the schematic of spring stiffness adjustment with an electronically controlled DC motor (319) in accordance with an embodiment of the present invention; and
Figure 8 represents the performance curve telescopic front fork for different velocities in accordance with an embodiment of the present invention.
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
The embodiments herein provide an adjustable high-velocity blow-off valve assembly for a telescopic front fork. The assembly can be retrofitted in the conventional telescopic front fork of the motorcycle.
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.”
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.
Hereinafter, embodiments will be described in detail. For clarity of the description, known constructions and functions will be omitted.
In one of the exemplary embodiments of the present invention, the blow-off valve assembly incorporates a blow-off valve with a spring, the stiffness of which can be adjusted with an adjuster assembly.
In one of the exemplary embodiments of the present invention, the blow-off valve assembly is provided with a certain profile interface(s) of the components to aid in the preload adjustment of the spring.
In one of the exemplary embodiments of the present invention, the stiffness of the spring can be adjusted with an electronically controlled motor.
In one of the exemplary embodiments of the present invention, the components of the blow-off valve assembly can be aluminum machined or plastic molded or can be fabricated from extruded aluminum.
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 and the table below.
Reference No. Component Reference No. Component
100 Adjustable high-velocity blow-off valve assembly 116 Bleed hole
101 Circlip 117 Rebound hole
102 Valve stem 118 Bolt cap
103 Valve casing 119 Damping rod
104 Dog-point screw 300 Preload adjuster
105 Plunger 300-a Preload adjuster screw assembly
106 Compression spring 300-b Preload adjuster rod interface
107 Blow-off valve 311 Circlip
108 Rebound spring 312 O-ring
109 Nut 313 Preload adjuster screw
110 Non-return valve 314 Preload adjuster rod
111 Spring seater 315 Bushed guide plate
112 Valve cap 316 Tube
113 Steel balls 317 Torquing head
114 Groove on the valve stem (102) to accommodate circlip (101) 318 Bush
115 Grooves on blow-off valve (107) to accommodate steel balls (113) 319 DC motor
400 Front fork
Figures 1(a) and 1(b) illustrate the assembly (100) in accordance with the preferred embodiment of the present invention. The assembly (100) comprises a plunger (105) and a valve stem (102) assembled inside a valve casing (103). A circlip (101) is assembled on the valve stem (102) groove (114) to lock the valve stem (102) in a position with the valve casing (103). A compression spring (106) is assembled between a spring seater (111) and the plunger (105). A non-return valve (110) with a rebound spring (108) is placed on the rebound side of the blow-off valve (107). A rebound spring (108) is seated on the surface of the valve cap (112). The rebound spring (108) can be a coil spring or a leaf spring. The valve cap (112) is torqued with the blow-off valve (107). A plurality of steel balls (113) is accommodated in grooves (115) provided in the blow-off valve (107). A nut (109) is torqued with the valve stem (102) and made to have contact with the valve cap (112).
Referring to Figure 2, components of the assembly (100) are fitted to adjust the preload of the compression spring (106). A dog-point screw (104) is fitted with the valve casing (103). The dog-point screw (104) facilitates to convert the rotation of the valve stem (102) to the linear motion of the plunger (105) to vary the preload of the compression spring (106).
In one of the exemplary embodiments of the present invention, the blow-off valve assembly (100) can be coupled with a preload adjuster screw assembly (300-a) as illustrated in Figure 3. The preload adjuster screw assembly (300-a) is coupled to the blow-off valve assembly (100) by a preload adjuster rod (314). Referring to Figure 3(a), the preload adjuster screw assembly (300-a) consists of a preload adjuster screw (313) assembled inside the bolt cap (118) with a circlip (311). An O-ring (312) is provided for preventing oil leakage through the bolt cap (118) and preload adjuster screw (313) interface. Referring to Figure 3(b), the preload adjuster rod (314) is designed to slide through a tube (316) during the compression of the fork. A bushed guide plate (315) provided for a bush (318) is designed with a D-slot crimped on the top side of the tube (316) to provide the guiding for the preload adjuster rod (314). Referring to Figure 3(c), a torquing head (317) is fixed at the bottom of the tube (316) and has a particular profile to ensure contact with the valve stem (102). In an exemplary embodiment of the present invention, the profile can be hexagonal or across-flat shaped.
Figure 4 shows the position-dependent perspective of the blow-off valve assembly (100), the preload adjuster screw assembly (300-a), and the preload adjuster rod interface (300-b) with respect to the front fork (400) in accordance with an embodiment of the present invention. The blow-off valve assembly (100) is placed on the piston of the conventional front fork (400), as illustrated in Figure 4-c. The main coil spring (not labelled) of the conventional front fork (400) is positioned on the valve casing (103) of the blow-off valve assembly (100). Referring to Figure 4-a, the preload adjuster screw assembly (300-a) is incorporated in the bolt cap (118). Figure 4-b shows the relative position of the preload adjuster rod (314) with respect to the blow-off valve assembly (100) and the adjuster screw assembly (300-a) when placed in the front fork (400) of the vehicle.
In one of the exemplary embodiments of the present invention, the assembly (100) can be used for low, medium, and high compression velocities. Referring to Figure 5(a), when the assembly (100) is installed on top of the damping rod (119), low and medium speed damping is controlled by bleed hole(s) (116) in the blow-off valve (107). Oil flows unrestricted from chamber A to the inside of the damping rod (119), then up toward chamber C. At the lowest velocities there is not enough pressure to open the blow-off valve (107) and the entire oil goes through the blow-off valve’s (107) bleed holes (116).
Referring to Figure 5(b), at higher velocities, particularly when the wheel encounters a square-edged bump or when landing from a jump, the fork (400) needs to move rapidly. The oil pressure builds in chamber A and beneath the blow-off valve (107) to a point that lifts the blow-off valve (107) off its seat, allowing the oil to flow into chamber C.
Referring to Figure 5(c), during the rebound stroke, oil flows through the rebound holes (117) in the blow-off valve (107) and starts to open the non-return valve (110) by compressing the rebound spring (108).
In one of the exemplary embodiments of the present invention, preload adjustment for the blow-off valve (107) is carried out by way of a particular movement of the preload adjuster screw (313). Referring to Figure 6(a) and Figure 6(b), when the preload adjuster screw (313) is rotated in a clockwise direction, its rotation is transferred to the blow-off valve stem (102) through the torquing head (317) by means of the D-slot and profile contact between the guide plate (315) and the preload adjuster rod (314). The rotation of the valve stem (102) is converted into the linear motion of the plunger (105) by the usage of a dog-point screw (104) in the valve casing (103). Because of this motion, the compression spring (106) starts to compress and the preload is increased on the blow-off valve (107). When the preload adjuster screw (313) is rotated in an anti-clockwise direction, the spring (106) starts to expand and the preload is decreased on the blow-off valve (107).
The stiffness of the spring (106) is adjusted with an electronically controlled DC motor (319) as shown in Figure 7. The DC motor (319) can be mechanically coupled to the preload adjustor rod (314).
Figure 8 represents the performance characteristics of the telescopic front fork (400) measured at different velocities. The curve 1 represents the targeted compression damping force at different velocities for the front fork (400). The curves (2 and 3) represent the performance characteristics of the telescopic front fork (400) including and excluding the blow-off valve therein. As seen from the trend of curve 1, the compression damping is more progressive in nature due orifice effect on high velocities. More progressiveness in damping gives discomfort to the rider. With larger compression holes in the piston, the targeted compression values couldn’t be achieved as seen in curve 3. Curve 2 represents the inclusion of the blow-off valve in the telescopic front fork that facilitates damping at a higher compressive damping force, where up to a particular velocity damping is maintained as targeted. After that blow-off valve is activated to reduce the progressiveness in the damping curve which results in a comfortable ride.
ADVANTAGES OF THE INVENTION
1. The assembly provides improved damper response with a digressive damping curve on large and sharp-edged bumps at high velocities without harshness.
2. The assembly facilitates tuning of low-velocity and high-velocity compression damping in telescopic front forks without disassembling the front fork.
3. The assembly results in better steering response in cornering, and provides comfortable riding.
4. The assembly can be installed in the telescopic front fork as a retrofit arrangement.
5. The assembly results in proper seating of the spring, thus ensuring proper guiding.

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. An adjustable high-velocity blow-off valve assembly (100) for a telescopic front fork (400), the assembly (100) comprising:
a plunger (105) and a valve stem (102) assembled inside a valve casing (103);
a circlip (101) assembled on the valve stem groove (114), the circlip (101) configured to lock the valve stem (102) with the valve casing (103);
a compression spring (106) assembled between a spring seater (111) and the plunger (105);
a non-return valve (110) with a rebound spring (108), the rebound spring (108) seated on a valve cap (112);
a blow-off valve (107) configured with a plurality of bleed holes (116) and a groove(s) (115), the blow-off valve (107) torqued with the valve cap (112); and
a plurality of balls (113) configured to get accommodated inside the groove(s) (115) in the blow-off valve (107).
2. The assembly (100) as claimed in claim 1, wherein, the rebound spring (108) can be a coil spring or a leaf spring.
3. The assembly (100) as claimed in claim 1, wherein, the valve casing (103) is fitted with a dog-point screw (104) that facilitates to convert the rotation of the valve stem (102) into the linear motion of the plunger (105).
4. The assembly (100) as claimed in claim 1 is mechanically coupled to a preload adjuster screw assembly (300-a) and a preload adjuster rod interface (300-b) to vary the preload of the compression spring (106).
5. The preload adjuster screw assembly (300-a) and the preload adjuster rod interface (300-b) as claimed in claim 4 including:
a preload adjuster screw (313) assembled inside the bolt cap (118) with a circlip (311);
an O-ring (312) configured to prevent oil leakage through the bolt cap (118) and preload adjuster screw interface;
the preload adjuster rod (314) configured to slide through a tube (316) during the compression of the fork (400);
a bushed guide plate (315) provided for a bush (318) designed with a D-slot crimped on the top side of the tube (316) to provide the guiding for the adjuster rod (314); and
a torquing head (317) fixed at the bottom of the tube (316) and provided a hexagonal or across-flat-shaped profile to ensure contact with the valve stem (102);
wherein,
the rotation of the preload adjuster screw (313) is transferred to the valve stem (102) through the torquing head (317) and a profile contact between the guide plate (315) and the preload adjuster rod (314) to get converted into the linear motion of the plunger (105) facilitated by the dog-point screw (104) in the valve casing (103) to adjust the preload on the blow-off valve (107).
6. The assembly (100) as claimed in claim 1 can be placed on the piston of the telescopic front fork (400) such that a main coil spring of the telescopic front fork (400) is positioned on the valve casing (103) of the assembly (100).
7. The assembly (100) as claimed in claim 1, wherein, the stiffness of the spring (106) is adjusted with an electronically controlled DC motor (319) mechanically coupled to the preload adjustor rod (314).

Dated this December 2, 2024

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