Description:FORM 2
The Patent Act 1970
(39 of 1970)
and
The Patent Rules, 2005

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

TITLE OF THE INVENTION
“NOISE AND MOTION ARRESTOR FOR A SHOCK ABSORBER”

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

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

Field of Invention

[001] The present invention relates to a noise and motion arrestor for a shock absorber of two and three wheeled vehicles. More particularly, the present invention relates to a noise and motion arrestor for a shock absorber adapted to eliminate the unwanted noise while in operation.

Background of the Invention

[002] A bump stop in rear shock absorber is commonly employed to avoid the bottoming of outer tube of the damper during the extreme compression stroke of the shock absorber. The said bump stop not only protects the outer tube but also imparts a smooth and comfortable ride to a user. In a typical rear shock absorber, the bump stop is usually positioned below a washer wherein the washer is generally positioned below the spring locator and around the outer peripheral surface of the piston rod. The washer is usually provided with a certain clearance and the bump stop is snuggly fitted with the outer peripheral surface of the piston rod wherein the piston rod is expected to reciprocate along with the bump stop during working of the shock absorber. This reciprocating motion of the piston rod causes a relative positional change of the bump stop followed by the dislocation of the washer from its place due the functional clearance in between the inner periphery of the washer and the outer periphery of the piston rod. Thus the said washer strikes against the spring locator during the cycling rebound strokes of the shock absorber and leads to generation of an annoying clattering sound. This sound not only gives a very uncomfortable feel to the rider leading to deterioration in quality of the shock absorber but also poses a challenge of the early failure of the parts viz. washer, spring locator of the shock absorber. Therefore, there is an unprecedented need to provide an unique and cost effective solution for the shock absorber assembly of vehicles that is intended to address and overcome the drawbacks in the prior art.

Objectives of the Present Invention

[003] The main object of the present invention is to provide a uniquely profiled noise and motion arrestor for a shock absorber.

[004] Another main object of the present invention is to provide a noise and motion arrestor for a shock absorber adapted to avoid the clattering noise during the working of the shock absorber and thereby enhancing the quality of the shock absorber.

[005] Another objective of the present invention is to provide a noise and motion arrestor capable of improving the lifecycle of the bump stop.

[006] Still another objective of the present invention is to provide a noise and motion arrestor capable of eliminating the application of adhesive and thus simplifying the manufacturing process thereby.

Brief Description of Drawings

[007] This invention is illustrated in the accompanying drawings, throughout which like reference numerals / 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

[008] Figure 1 discloses the cut view of the shock absorber depicting the noise and motion arrestor as per the present invention.

[009] Figures 2a, 2b and 2c present the perspective view, top view and cut sectional view, respectively of the noise and motion arrestor of the present invention.

[0010] Figure 3 discloses the cut-sectional view of the noise and motion arrestor fitted with the piston rod in accordance with the present invention.

[0011] Figure 4 discloses the cut-sectional view from the top of the noise and motion arrestor fitted with the piston rod in accordance with the present invention.

Detailed Description of the Present Invention

[0012] 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.

[0013] Referring to Fig. 1, the noise and motion arrestor (200) of the present invention is adapted to be fitted to a shock absorber (100) so as to avoid the technical drawbacks experienced by the said shock absorber (100). The shock absorber (100) includes a piston rod (50) having a piston (not shown) being telescopically disposed within a damper (70) at its one end and connected to an extension assembly (10) at the other end. A spring locator (20) is fitted with the piston rod (50) and a spring seat (80) is fixed on the damper body (70). The spring (60) is positioned in between the spring locator (20) and the spring seat (80). A mounting bracket (90) is fixedly connected to the bottom of the damper (70). The noise and motion arrestor (200) is snuggly fitted with the piston rod (50) below the spring locator (20) and a bump stop (40) is fitted below the said noise and motion arrestor (200) over the piston rod (50). A dust cover (30) is positioned around the periphery of the piston rod (50) so as to avoid the entry of dust and other foreign particles in the shock absorber (100). The said shock absorber (100) is mounted to the vehicle in a manner such that the extension assembly (10) is fitted with the chassis of the vehicle (under seat) and the mounting bracket (90) is fitted with the swing arm of the vehicle.

[0014] Referring to Figs. 2a to 4, the noise and motion arrestor (200) is a cylindrical disc configured to have a main body portion (200B) and a central portion (200C). The said central portion (200C) is configured to have a ramp surface (200R) on its top face and bottom face and a star-shaped opening (200S). The ramp surface (200R) forms a negative gradient towards the star-shaped opening (200S) from the top surface of the main body portion (200B) and the forms a positive gradient towards the star-shaped opening (200S) from the bottom surface of the main body portion (200B) of the noise and motion arrestor (200). The ramp surface (200R) of the noise and motion arrestor (200) is configured to have a gradient angle (α). The gradient angle (α) of the ramp surface (200R) ranges in between 1 to 20O. The star-shaped opening (200S) of the noise and motion arrestor (200) facilitates the smooth entry of the piston rod (50) within the star-shaped opening (200S) during the assembly of the shock absorber (100).

[0015] Further, star-shaped opening (200S) of the noise and motion arrestor (200) has a plurality of V-shaped trenches (200V) wherein the said trenches (200V) are interconnected with each other with the help of an arcuate bridge segment (200M). The trenches (200V) and the arcuate bridge segments (200M) are usually selected to in an odd numbered arrangement so as to have a trench (200V) arranged in a diagonally opposite relation to the respective bridge segment (200M). The number of arcuate bridge segments (200M) is kept in accordance to have desired contact surface between the piston rod (50) and the opening (200S) which is achieved in a combination of five number of trenches (200V) and five number of bridge segment (200M). The number of the said trenches (200V) and the bridge segment (200M) may however be varied in an odd number as per the requirement e.g. three trenches (200V) and three bridge segments (200M), five trenches (200V) and five bridge segments (200M), seven trenches (200V) and seven bridge segments (200M), and like.

[0016] Further, each of the arcuate bridge segments (200M) of the noise and motion arrestor (200) is configured to have an interference (δ) with the piston rod (50). This intelligently defined interference (δ) between the arcuate bridge segments (200M) and the outer peripheral surface of the piston rod (50) tightly holds the noise and motion arrestor (200) at its place during the working of the shock absorber (100). The interference (δ) is defined as the ratio in between the inner diameter (Ødi) of an imaginary circle formed by joining the arcuate bridge segments (200M) and the outer diameter (Ødo) of the piston rod (50). The said interference (δ) ranges from 0 to 1.0 mm so as to securely hold the noise and motion arrestor (200) at its place while also allowing the reciprocating motion of the piston rod (50) during the compression and the rebound strokes of the shock absorber (100). Also, the interference (δ) is calculated by keeping in consideration the surface roughness value of the noise and motion arrestor (200) and the piston rod (50) wherein the piston rod (50) is generally made from steel material whereas the noise and motion arrestor is made from plastic. The outer peripheral surface of the piston rod (50) is configured to have surface roughness (Ra) ranging from 0.01 to 0.25 µm. Thus, the said interference (δ) and the surface roughness (Ra) securely hold the noise and motion arrestor (200) at its place without requiring additional process of adhesive application during the compression and the rebound strokes of the shock absorber (100).

[0017] The noise and motion arrestor (200) of the present invention provides the following technical advantages that contributes to the advancement of technology:
- It eliminates the noise by avoiding the vertical movement of washer along with the damper stroke.
- It eliminates the additional process of adhesive application on washer surface.
- Cycle time reduction and cost saving because of adhesive elimination.
- Simple and easily implementable design solution.

[0018] 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 invention herein has been described in terms of a generalized form, those skilled in the art will recognize that the invention herein can be practiced with modification within the spirit and scope of the invention as described herein. , Claims:We Claim

1. A noise and motion arrester (200) for a shock absorber (100) of a vehicle, the shock absorber having a bump stop (40), a spring locator (20), a spring seat (80), a spring (60) and a piston rod (50)
wherein,
- the noise and motion arrestor (200) is a cylindrical disc and is configured to have a main body portion (200B) and a central portion (200C);
- said central portion (200C) of the noise and motion arrestor (200) is configured to have a ramp surface (200R) on its top face and bottom face and a star-shaped opening (200S); and
- said noise and motion arrestor (200) is snuggly fitted with the piston rod (50) in between the spring locator (20) and a bump stop (40).

2. The noise and motion arrester (200) for a shock absorber (100) as claimed in claim 1, wherein
- the ramp surface (200R) of the noise and motion arrestor is configured to form a negative gradient towards the star-shaped opening (200S) from the top surface of the main body portion (200B) and forms a positive gradient towards the star-shaped opening (200S) from the bottom surface of the main body portion (200B) of the noise and motion arrestor (200);
- said ramp surface (200R) of the noise and motion arrestor (200) is configured to have a gradient angle (α); and
- the star-shaped opening (200S) of the noise and motion arrestor (200) is configured to facilitate the smooth entry of the piston rod (50) within said star-shaped opening (200S) during assembly of the shock absorber (100).
3. The noise and motion arrester (200) for a shock absorber (100) as claimed in claim 2, wherein the gradient angle (α) of the ramp surface (200R) ranges in between 1O to 20O.

4. The noise and motion arrester (200) for a shock absorber (100) as claimed in claim 2, wherein
- the star-shaped opening (200S) of the noise and motion arrestor (200) is configured to have V-shaped trenches (200V) and said trenches (200V) are interconnected with each other with the help of an arcuate bridge segment (200M);
- said trenches (200V) and said arcuate bridge segments (200M) are selected in an odd numbered arrangement so as to have a trench (200V) arranged in a diagonally opposite to the respective bridge segment (200M); and
- said arcuate bridge segments (200M) are configured to have contact surface between the piston rod (50) and the opening (200S) of the noise and motion arrestor (200).

5. The noise and motion arrester (200) for a shock absorber (100) as claimed in claim 4, wherein
- each of the arcuate bridge segments (200M) of the noise and motion arrestor (200) is configured to have an interference (δ) with the piston rod (50);
- the interference (δ) is defined as the ratio in between the inner diameter (Ødi) of an imaginary circle formed by joining the arcuate bridge segments (200M) and the outer diameter (Ødo) of the piston rod (50);
- the outer peripheral surface of the piston rod (50) is configured to have surface roughness (Ra); and
- said interference (δ) and the surface roughness (Ra) are configured to securely hold the noise and motion arrestor (200) at its place without requiring additional process of adhesive application during the compression and the rebound strokes of the shock absorber (100).

6. The noise and motion arrester (200) for a shock absorber (100) as claimed in claim 5, wherein the noise and motion arrestor (200) is made of plastic and the piston rod (50) is made from steel material.

7. The noise and motion arrester (200) for a shock absorber (100) as claimed in claim 5, wherein the interference (δ) ranges from 0 to 1.0 mm so as to securely hold the noise and motion arrestor (200) at its place during working of the shock absorber (100).

8. The noise and motion arrester (200) for a shock absorber (100) as claimed in claim 5, wherein the outer peripheral surface of the piston rod (50) is configured to have surface roughness (Ra) ranging from 0.01 to 0.25 µm.

Dated this 27th day of Aug., 2024

Sahastrarashmi Pund
Head – IPR
Endurance Technologies Ltd.

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