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
“DUST SEAL STOPPER ASSEMBLY FOR SUSPENSION OF A TWO-WHEELER”

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 dust seals for a front fork suspension of a two wheeled vehicle. More particularly, the invention is related to a dust seal stopper assembly for eliminating the requirement of a wire stopper and preventing the ingression of foreign particles inside the working chamber of the front fork.

Background of the Invention

[002] A front fork type suspension is employed in a two wheeled vehicle wherein the said suspension is positioned in between the wheel axle and vehicle frame for providing a comfortable ride to the user. The front fork includes an outer tube and an inner tube (fork tube) wherein the outer tube is attached to a vehicle wheel side and the inner tube is attached to the vehicle frame side. The inner tube is coaxially and slidably inserted into the outer tube. The outer tube of the front fork is configured to have a working chamber having a working fluid therein and includes a dust seal member and an oil seal member wherein the said seal members are positioned in an annular space in between the outer tube and the inner tube at the mouth of the said outer tube.

[003] In the front fork, mud, sand, and other foreign matter easily adhere to an outer circumferential surface of the inner tube while the vehicle is running. The dust seal member and the oil seal member are arranged in series for preventing the entry of the dust particles and other foreign matter within the working chamber. The oil seal member includes an upper lip and a lower lip which prevents the working fluid to flow outside the working chamber of the front fork, whereas the dust seal scrapes off foreign substances adhering to an outer circumferential surface of an inner tube.

[004] A circular wire stopper is generally provided in between the dust seal member and the oil seal member which is used to lock the movement of the oil seal. The arrangement and fixing of the wire stopper on the oil seal leads to an increased assembly cycle time. Also, the wire stopper has a tendency to pop out from the groove of the outer tube if not fixed in a correct manner. This leads to the ejection of the oil seal from the outer tube which in turn leads to the oil leakage, seal deterioration, and failure of the intent of providing suspension in a vehicle leading uncomfortable and painful ride for the rider/user of the vehicle.

[005] To address the aforementioned problem and/or lacunae of the conventional sealing practices, there is a long pending unmet need to provide an intelligent solution that will ensure a positive locking of the oil seal and facilitates the ease of assembly on the production line, reduce the operator fatigue, leak-proof seal, and scrapes off foreign substances adhering to an outer circumferential surface of an inner tube during the running condition of the vehicle providing a superior and comfortable ride for the rider.

Objective of the Present Invention

[006] The main objective of the invention is to provide a dust seal stopper assembly for front fork suspension of a vehicle.

[007] Another objective of the present invention is to provide a dust seal cum stopper that completely eliminates the requirement of an extra wire stopper for locking the oil seal inside the circumferential gap of a fork tube and an outer tube.

[008] Yet another objective of the present invention is to provide a dust seal cum stopper having an L-shaped collar of metal insert inside the rubber dust seal that increases the strength of the dust seal cum stopper.

[009] Yet another objective of the present invention is to provide a dust seal cum stopper that scrapes off foreign substances adhering to an outer circumferential surface of an inner tube.

[0010] Still, the objective of the present invention is to provide a dust seal cum stopper that reduces the assembly cycle time, damage to the oil seal, and operator fatigue.

[0011] Yet the objective of the present invention is to provide a dust seal cum stopper that can be easily be manufactured reducing the operational steps in its manufacturing.

Brief Description of the Drawings

[0012] This invention is illustrated in the accompanying drawings, throughout which like reference letters / numerals 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

[0013] Figure 1 presents an isometric cut view of the fork leg of front suspension in accordance with an embodiment of the present invention.

[0014] Figure 2 presents an exploded cut view of the dust seal stopper assembly of the invention accommodated inside the circumferential gap of the fork tube and outer tube of suspension of a two-wheeler.

[0015] Figures 3 and 4 present an enlarged isometric cut views from different angles of the dust seal stopper assembly of the invention fitted within the fork leg of front suspension in accordance the present invention.

[0016] Figure 5 presents an isometric line diagram of the dust seal stopper assembly of the front fork in accordance the present invention.

[0017] Figure 6 presents cut view of the dust seal stopper assembly of the front fork in accordance the present invention.

Detailed Description of the Present Invention

[0018] 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. Referring to Figs. 1 and 2, a telescopic front fork (100) for a two wheeled vehicle has a fork tube (10), an outer tube (20) and a dust seal stopper assembly (S) wherein, the fork tube (10) is slidably inserted into the outer tube (20). The fork tube (10) telescopically slides into the outer tube (20) whenever the vehicle is running on the irregularity of road.

[0019] The fork tube (10) comprises of an assembly of a spacer, a main spring and a seat pipe, where one end of the fork tube (10) is fixed with a steering stem by a fastening means and the other end is slidably housed in the outer tube (20). The said outer tube (20) contains a working fluid therein, where one end of the said outer tube (20) is fixed with a wheel axle by a fastening mean and the other end of the outer tube (20) allows the fork tube (10) to slide axially therein.

[0020] Referring to Figs. 3 and 4, the telescopic front fork assembly (100) is configured to have a circumferential space (80) in between an annular region formed by the outer tube (20) and the fork tube (10). The outer tube (20) is configured to have a plurality of stepped profiles viz. P3, P2 and P1at its mouth end wherein the said profiles progresses in an order of gradually decreasing internal diameter form the top open end (mouth) of the said outer tube (20). Thus the diameter of the stepped profile P3 is greater than the diameter of the stepped profile P2 and further the diameter of the stepped profile P2 is greater than the diameter of the stepped profile P1. The stepped profile P3 forms a radial space with the fork tube (10) in its assembled condition. Further, the outer tube (20) is configured to have a groove (10G) formed at the interfacing boundary of profiles P2 and P3 as shown in Figure 3. Thus, the said groove (10G) separates the stepped profile P2 from P3.

[0021] The dust seal stopper assembly (S) of the present invention is housed in the circumferential space (80) wherein the said dust seal stopper assembly (S) comprises of a seal stopper (30), an oil seal (40), a rest washer (50), and a bush (60). The said bush (60) is press-fitted inside the profile P1 is such a way that the outer surface of said bush is in contact with an inner peripheral surface of the outer tube (20) and the inner surface of the bush (60) is in contact with the outer surface of the fork tube (10). The said bush (60) is configured to reduce the sliding resistance of the outer surface of the fork tube (10) during the sliding action of said fork tube (10) within the outer tube (20).

[0022] A rest washer (50) is placed just above the bush (60) in the stepped profile P2. The stepped profile P2 is also configured to receive an oil seal (40) above the rest washer, where the said oil seal (40) comprises of an upper lip (40U) and a lower lip (40L) extending towards the outer surface of the fork tube (10). The upper lip (40U) and the lower lip (40L) are provided with a reinforcement ring (40R) and said reinforcement ring (40R) facilitates a robust grip of the oil seal (40) with the fork tube (10) thus ensuring sound and leak-proof sealing.

[0023] Further, the step profile (P3) is configured to receive a seal stopper (30). The main function of the seal stopper is to restrict the ingress of dust and other foreign particulate matter towards the oil seal (40) within the outer tube (20) and at the same time it is configured to function as a lock / stopper for the oil seal (40). Referring to Figs. 5 and 6, the said seal stopper (30) is configured to have a rubber body (32) and a metal insert (34). The rubber body (32) is profiled to have a lip (32DL) at its inner diameter projecting towards the fork tube (10) and said rubber body (32) is intelligently over molded with the metal insert (34) to form an integrated unit of the seal stopper (30). Further, the rubber body (32) has a lip (32S) projecting towards an outer circumferential side of the outer tube (20). The lip (32DL) of the said rubber body is intended to work as the dust seal and is configured to restrict the entry of dust within the outer tube (20). The metal insert (34) has an L-shape collar (MC) at its top end (34A) and bottom end (34B). The said L-shaped collar (MC) at the top end (34A) of the metal insert (34) is configured to receive the rubber body (32) by over molding process. Thus, the rubber body (32) is intelligently over molded with the L-shaped collar (MC) of the top end (34A) of the metal insert (34). This unique construction of the rubber body (32) and the metal insert (34) forming an integrated unit of seal stopper (30) not only acts as a dust seal but also acts as a stopper for the oil seal (40).

[0024] The lip (32S) of the seal stopper (30) projecting towards the outer circumferential side of the outer tube (20) has L-shape collar (MC) of the top end (34A) of the metal insert (34) therein. This unique construction of the lip (32S) of the seal stopper (30) not only reinforces the seal stopper (30) but also acts as a stopper for the oil seal (40) preventing the popping out the said oil seal (40). The dust lip (32DL) extends towards the outer surface of the fork tube (10) and slides over the outer circumferential surface of the fork tube (10) so as to restrict the ingression of the foreign particles inside the working chamber. The L-shaped collar (MC) at the bottom end (34B) of the metal insert (34) is fitted inside the groove (10G) which is provided on the inner circumferential surface of the outer tube (20) above the stepped profile (P2). This unique fitment of the bottom end (34B) of the metal insert (34) inside the groove (10G) locks the seal stopper (30) tightly in its position and prevents the movement of the oil seal (40). This unique assembly (S) of the seal stopper (30), the oil seal (40), rest washer (50) and the bush (60) and its fitment in the stepped profiles (P3, P2 and P1) in the mouth of the outer tube (20) completely eliminates the requirement of the wire stopper for locking the movement of the oil seal (40) making it compact, simple and cost effective dust seal stopper assembly (S).

[0025] In some variants of the front suspension of the vehicle, the outer tube (20) has two stepped profiles (P2 and P3) with varying internal diameter in its mouth. the stepped profile (P3) is formed at the distal end of the mouth of the outer tube (20) and said stepped profile (P3) has an internal diameter greater than the internal diameter of the stepped profile (P2). The stepped profiles (P2 and P3) are separated by a groove (10G) is provided in the inner peripheral surface of the mouth of the outer tube (20).

[0026] In these variants of the suspension, the oil seal (40) along with the washer (50) is positioned in the stepped profile (P2) for ensuring airtight and leak-proof sealing. The seal stopper (30) is positioned inside the stepped profile (P3) in such a way that the L-shaped collar (MC) at the bottom end (34B) of the metal insert (34) gets locked inside the groove (10G) preventing the movement of the oil seal (40). This unique assembly (S) of the seal stopper (30), the oil seal (40) and rest washer (50) and its fitment in the stepped profiles (P3 and P2) in the mouth of the outer tube (20) completely eliminates the requirement of the bush (60) and the wire stopper for locking the movement of the oil seal (40) making it very compact, simple and cost effective dust seal stopper assembly (S) in line with the intent of the present invention.

[0027] Thus, the novelty of the invention lies in the integrated unit of seal stopper (30) and said seal stopper (30) forming a unique assembly (S) with the oil seal (40), rest washer (50) and the bush (60) and its fitment in the stepped profiles (P3, P2 and P1) in the circumferential space (80) in the mouth of the outer tube (20). This novel construction of the dust seal stopper assembly (S) of the invention imparts following technical advantages that contribute to the technical advancement of the sealing assembly for front fork suspension of a vehicle qualifying the test of inventive step:
- The dust seal stopper assembly of the invention eliminates the requirement of a wire stopper for locking the oil seal.
- It ensures the positive locking of oil seal and offer flat resting surface to lock oil seal movement.
- The lip of the dust seal stopper assembly efficiently scrapes off foreign substances adhering to an outer circumferential surface of an inner tube.
- The use of L-shape collar of metal insert inside the rubber body increasing the strength of the seal stopper.
- It is easy to manufacture reducing the assembly cycle time of seal assembly.
- It provides very compact, simple and cost effective solution of the dust seal stopper assembly.

[0028] The foregoing description of the specific embodiment of the invention will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. Further, it is to be understood that the phraseology or terminology employed herein are for the purpose of description and not of limitation. Therefore, while the embodiment/s 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 dust seal stopper assembly (S) for suspension of a two wheeler comprising of a seal stopper (30), an oil seal (40), a rest washer (50) and a bush (60)
wherein,
- the seal stopper (30) is configured to have a rubber body (32) and a metal insert (34); said rubber body (32) is profiled to have a lip (32DL) at its inner diameter projecting towards the fork tube (10); and said rubber body (32) is over molded with the metal insert (34) to form an integrated unit of the seal stopper (30);
- the bush (60) is press-fitted inside the stepped profile (P1) of the outer tube (20) is such a way that the outer surface of said bush (60) is in contact with an inner peripheral surface of the outer tube (20) and the inner surface of the bush (60) is in contact with the outer surface of the fork tube (10);
- the oil seal (40) is configured to have an upper lip (40U) and a lower lip (40L) extending towards the outer surface of the fork tube (10); and said oil seal (40) along with the rest washer (50) is positioned in the stepped profile (P2) of the outer tube (20) above the bush (60); and
- said seal stopper (30) is fitted in the stepped profile (P3) of the outer tube (20) in such a way that the metal insert (34) of the seal stopper (30) gets locked in a groove (10G) of the outer tube (20) to restrict the movement of the oil seal (40).

2. The dust seal stopper assembly (S) for suspension of a two wheeler as claimed in claim 1, wherein
- the rubber body (32) of the seal stopper (30) is configured to have a lip (32S) projecting towards an outer circumferential side of the outer tube (20);
- the metal insert (34) of the seal stopper (30) has an L-shape collar (MC) at its top end (34A) and bottom end (34B);
- and said L-shaped collar (MC) at the top end (34A) of the metal insert (34) is configured to receive the rubber body (32) by over molding process.

3. The dust seal stopper assembly (S) for suspension of a two wheeler as claimed in claim 2, wherein the upper lip (40U) and the lower lip (40L) of the oil seal (40) have a reinforcement ring (40R), and said reinforcement ring (40R) is configured to have a robust grip of the oil seal (40) with the fork tube (10) ensuring sound and leak-proof sealing.

4. The dust seal stopper assembly (S) for suspension of a two wheeler as claimed in claim 2, wherein
- the L-shaped collar (MC) at the bottom end (34B) of the metal insert (34) is fitted inside the groove (10G) provided on the inner circumferential surface of the outer tube (20) above the stepped profile (P2); and
- said fitting of the L-shaped collar (MC) of the bottom end (34B) of metal insert (34) inside the groove (10G) is configured to lock the seal stopper (30) tightly in its position and prevent the movement of the oil seal (40).

5. The dust seal stopper assembly (S) for suspension of a two wheeler as claimed in claim 4, wherein
- the outer tube (20) is configured to have a plurality of stepped profiles (P3, P2 and P1) at its mouth end and said profiles progresses in an order of gradually decreasing internal diameter form the top open end (mouth) of the said outer tube (20);
- said outer tube (20) is configured to have a groove (10G) formed at the interfacing boundary of profiles P2 and P3 separating the stepped profile P2 from P3;
- the diameter of the stepped profile P3 is greater than the diameter of the stepped profile P2 and the diameter of the stepped profile P2 is greater than the diameter of the stepped profile P1.

6. The dust seal stopper assembly (S) for suspension of a two wheeler as claimed in any of the previous claims, wherein said dust seal stopper assembly (S) is housed in the circumferential space (80) in between an annular region formed by the outer tube (20) and the fork tube (10) of the suspension (100).

Dated this 21st day of June 2024

Sahastrarashmi Pund
Head – IPR
Endurance Technologies Ltd.

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