Claims:We Claim:

1. A dust seal (100) for front fork suspension of a vehicle comprising of a hollow cylindrical base (5), a hollow conical top body (45), and a curved flap (15)
wherein,
- the hollow conical top body (45) is joined to the hollow cylindrical base (5) to form an integral unit and the curved flap (15) is formed with the said unit along the joint of the hollow conical top body (45) and the hollow cylindrical base (5) in such way that the curved flap (15) is projected vertically and displaced outside the outer surface of the hollow cylindrical base (5) in the radial direction of the said hollow cylindrical base (5); and
- said curved flap (15) is profiled over the hollow cylindrical base (5) in such way that the extreme edges (15e and 15f) of the flap (15), that connects at the cylindrical base (5), makes an angle of at least 180 degrees with the center of the hollow conical top body (45) and any point on the inner surface (15b) of the curved flap (15) along the same horizontal plane is equidistant from the central axis from the hollow conical top body (45).

2. The dust seal (100) for front fork suspension of a vehicle as claimed in claim 1, wherein
- the dust seal (100) has a plurality of equally spaced openings (25) on the curved flap (15) and the said openings (25) are in the same horizontal plane on the projecting curved flap (15); and
- the dust seal (100) has a plurality of equally spaced openings (35) along the joint between the hollow cylindrical base (5) and the curved flap (15) on the displaced base (15c) of the curved flap (15).

3. The dust seal (100) for front fork suspension of a vehicle as claimed in claim 2, wherein
- the hollow cylindrical base (5) has a thick annular ring (5a) on its inside curved surface along the lower edge;
- said thick annular ring (5a) has a top flat surface (5aa), a middle cylindrical curved surface (5ab) and a lower surface (5ac); and
- the lower surface (5ac) is slopped in an outward direction to facilitate easy mounting of the dust seal (100) onto a groove (110aa) given on the front fork outer tube (110).

4. The dust seal (100) for front fork suspension of a vehicle as claimed in claim 3, wherein
- the hollow conical top body (45) has an inside lower flat surface (45ac) that forms the upper boundary of the hollow cylindrical base (5) on the inside curved surface;
- the hollow conical top body (45) has a inwardly curved profile with a circular opening (45aa) on its top;
- the hollow conical top body (45) has an inner lip (45c) along the upper opening (45aa) and an inner lip (45d) below the inner lip (45c) separated by a curved surface (45cd); and
- the inner lip (45d) forms the upper edge of an inside curved surface (45ab) and the inside lower flat surface (45ac) forms the lower edge of the inside curved surface (45ab).

5. The dust seal (100) for front fork suspension of a vehicle as claimed in claim 4, wherein the plurality of equally spaced openings (25) are profiled to have conical cross section projecting inside (25a) towards the top conical body (45) at the inner face (15b) of the curved flap (15) that direct air onto the outer curved surface of the hollow conical top body (45).

6. The dust seal (100) for front fork suspension of a vehicle as claimed in claim 4, wherein the plurality of equally spaced openings (25) are selected from a set of profiles of rectangular slits; said slits inclined right, inclined left and combination thereof and the said profiles are configured to have converging cross section projecting inside (25a) towards the hollow conical top body (45) at the inner face (15b) of the curved flap (15) creating the venturi to direct air onto the outer curved surface of the hollow conical top body (45).

7. The dust seal (100) for front fork suspension of a vehicle as claimed in claim 5 or 6, wherein the plurality of equally spaced openings (25) are angularly displaced from the plurality of equally spaced openings (35) such that when the dust seal (100) is viewed from the top, the plurality of equally spaced flap surface opening (25) do not lie along the same imaginary line proceeding outwards from the center of the circular opening (45aa).

8. The dust seal (100) for front fork suspension of a vehicle as claimed in claim 7, wherein the hollow conical top body (45) is profiled to have a lower outer portion (45L) having steeper slope than its top outer portion (45U).

9. The dust seal (100) for front fork suspension of a vehicle as claimed in claim 8, wherein the thick annular ring (5a) has a projection (5ad) that rotationally locks the dust seal (100) to a matching recess (110ab) given on the front fork outer tube (110).

Dated this 2nd day of September 2021.

Sahastrarashmi Pund
Head – IPR
Endurance Technologies Limited

To,
The Controller of Patents,
The Patent Office, at Mumbai. , Description: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 FOR FRONT FORK SUSPENSION OF A 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 dust seal for front fork suspension of a vehicle. More particularly, the invention is related to dust seal with a shield for protecting the front fork inner tubes against impact of foreign objects and openings for air circulation and fluid evacuation.

Background of the Invention

[002] Conventionally the dust seals are employed in the front fork suspension for preventing the entry of dust into the outer tube and also to facilitate the smooth movement inner tube inside the outer tube without subjecting to any scratches thereon. The dust seals are normally installed in a groove given on open end of the outer tube. Such dust seals are ordinarily provided with metallic reinforcement within their polymeric body to provide them with sufficient structural rigidity. As the metallic reinforcement cannot be manufactured and moulded into the polymeric body in the same step, such dust seals have to be manufactured in multiple steps. This adds to the time and cost of manufacturing such dust seals.

[003] Further, to protect the inner tube from the impact of foreign objects/stones in moving condition of the vehicles, protector is generally employed in the front fork suspension. These protectors are mounted on the outer side of the outer tube in a specially made grooves therefor. This adds to the additional operation of providing the grooves on the outer top surface of the outer tube during its manufacturing.

[004] The dust seals so manufactured are faced with other limitations as well. One such limitation is that it is very hard to provide any pathway or holes within the seals that allow for evacuation of fluids (most commonly mud) from in between the base of the impact protectors and the dust seals. Given that dust seals are typically not sufficiently thick, providing such pathways or holes leads to weaken the dust seal along multiple points thereby reducing their life in the process. It is for this very reason the impact protectors also cannot be provided with any pathways or holes to facilitate air circulation over the inner tube of the front fork so as to dissipate the heat generated due to continuous movement of the inner tube. These factors ultimately affect the front fork by allowing foreign objects to accumulate between the impact protector and the dust seal. The accumulated foreign objects increase the risk of inner tube of the front fork getting scratched. The scratched inner tube can rub against the oil seals and damage them as well thereby causing leakages along sliding surface of the inner and outer tubes.

[005] Providing the impact protectors and dust seal is necessary when the vehicle is likely to be used in off-road and/or dusty road conditions. Removing the protectors after every such ride for cleaning purpose is not always an optimum solution for this problem. As the space available between the impact protectors, dust seal and the inner tube of the front fork is very limited, frequent cleaning is also not very effective in removing all the accumulated foreign dirt and entrapped foreign objects. To address this problem, there is a long pending unmet need to provide an intelligent solution that will ensure the removal of dirt and foreign objects by itself during the running condition of the vehicle. Therefore, for overcoming the cited limitations of the existing dusts seals and fulfilling the important requirement of protecting the front fork inner tube from impacts of stones and other foreign objects the following invention is disclosed. The solution described in the invention addresses all these gaps and ensure its self-cleaning, reduces the operations required to manufacture the seals and outer tube and drastically reduces the cycle time for assembly of outer tube with seal and the protector.

Objectives of the Invention

[006] The main object of the present invention is to provide a dust seal that does not allow accumulation of any foreign objects between itself and the impact protector.

[007] Another object of the present invention is to provide a dust seal that has desired structural rigidity to effectively function as a dust seal and stone impact protector.

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

[009] Yet, the objective of the invention is to provide a dust seal with protector that ensures efficient heat dissipation from the inner tube and reduces the assembly time of outer tube with seal and protector.

Summary of the Invention

[0010] To achieve the stated objectives of the invention, a dust seal for front fork suspension is provided which comprises of a hollow cylindrical base, a hollow conical top body and a curved flap. The hollow conical top body of the dust seal is joined to the hollow cylindrical base to form an integral unit and the curved flap is integrated with the said unit along the joint of the hollow conical top body and the hollow cylindrical base in such way that the curved flap is projected vertically and displaced outside the outer surface of the hollow cylindrical base in the radial direction of the said hollow cylindrical base. The curved flap of the dust seal is profiled over the hollow cylindrical base in such way that the extreme edges of the flap, that connect at the cylindrical base, make an angle of at least 180 degrees with the center of the hollow conical top body. In the disclosed dust seal any point on the inner surface of the curved flap along the same horizontal plane is equidistant from the central axis from the hollow conical top body.

[0011] Typically, the dust seal has a plurality of equally spaced openings on the curved flap and the said openings are in the same horizontal plane on the projecting curved flap; and the dust seal has a plurality of equally spaced openings along the joint between the hollow cylindrical base and the curved flap on the displaced base of the curved flap. The hollow cylindrical base has a thick annular ring on its inside curved surface along the lower edge, the thick annular ring has a top flat surface, a middle cylindrical curved surface and a lower surface, and the lower surface is slopped in an outward direction to facilitate easy mounting of the dust seal onto a groove given on the front fork outer tube.

[0012] The hollow conical top body has an inside lower flat surface that forms the upper boundary of the hollow cylindrical base on the inside curved surface, the hollow conical top body has a inwardly curved profile with a circular opening on its top, the hollow conical top body has an inner lip along the upper opening and an inner lip below the inner lip separated by a curved surface, and the inner lip forms the upper edge of an inside curved surface and the inside lower flat surface forms the lower edge of the inside curved surface. The plurality of equally spaced openings are profiled to have conical cross section projecting inside towards the top conical body at the inner face of the curved flap that direct air onto the outer curved surface of the hollow conical top body.

[0013] Typically, the plurality of equally spaced openings are selected from a set of profiles of rectangular slits, said slits inclined right, inclined left and/or combination thereof and the said profiles are configured to have converging cross section projecting inside towards the hollow conical top body at the inner face of the curved flap making the venturi effect to direct air onto the outer curved surface of the hollow conical top body. The plurality of equally spaced openings are angularly displaced from the plurality of equally spaced openings such that when the dust seal is viewed from the top, the plurality of equally spaced flap surface opening do not lie along the same imaginary line proceeding outwards from the center of the circular opening. The hollow conical top body is profiled to have a lower outer portion having steeper slope than its top outer portion. The thick annular ring has a projection that rotationally locks the dust seal to a matching recess given on the front fork outer tube.

Brief Description of the Drawings

[0014] 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

[0015] Figure 1 presents the isometric view of the dust seal in accordance with an embodiment of the present invention.

[0016] Figure 2 shows the rear view of the dust seal of the present invention as shown in Fig. 1 when mounted on the front fork of the vehicle.
[0017] Figure 3 presents vertical cut sectional view of the dust seal in accordance the present invention.

[0018] Figure 4 shows the top view of the dust seal in accordance with an embodiment of the present invention.

[0019] Figure 5 presents another cut sectional view of the dust seal in accordance with the present invention.

[0020] Figure 6 presents an isometric view of the dust seal with rectangular slits / openings on its curved flap in accordance with another embodiment of the present invention.

[0021] Figure 7 shows the front view of the dust seal disclosed in Fig. 6.

[0022] Figure 8 presents vertical cut sectional view of the dust seal of the invention as disclosed in Fig. 6.

[0023] Figure 9 presents an isometric view of the dust seal with inclined openings on its curved flap in accordance with another embodiment of the present invention.

[0024] Figure 10 shows the front view of the dust seal as disclosed in Fig. 9.

[0025] Figure 11 shows cut sectional view of the dust seal with inclined openings on its curved flap in accordance with an embodiment of the present invention.

[0026] Figure 12 shows the dust seal of the invention in an assembled condition over a front fork suspension of a vehicle.

Detailed Description of the Present Invention

[0027] 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.

[0028] The dust seal in accordance an embodiment of the present invention as shown Figs. 1, 3 and 4 comprises of a hollow cylindrical base (5), a hollow conical top body (45), and a curved flap (15). The hollow conical top body (45) is joined to the hollow cylindrical base (5) to form an integral unit and the curved flap (15) is formed with the said unit along the joint of the hollow conical top body and the hollow cylindrical base in such way that the curved flap (15) is projected vertically and displaced outside the outer surface of the hollow cylindrical base in the radial direction of the said hollow cylindrical base. This makes the dust seal (100) stiffer and stronger along the joint between the curved flap (15), the hollow cylindrical base (5) and the hollow conical top body (45). This feature strengthens the dust seal and provides it with capacity to resist being damaged along the joint.

[0029] The curved flap (15) is profiled over the hollow cylindrical base (5) in such way that the extreme edges (15e and 15f) of the flap (15), that connects at the cylindrical base, makes an angle of at least 180 degrees with the center of the hollow conical top body (45). The curved flap (15) is so profiled that, any point on the inner surface (15b) of the curved flap (15) along the same horizontal plane is equidistant from the central axis from the hollow conical top body (45) (refer Figs. 2, 4, 6 and 9). Structurally, this means that the curved flap (15) proceeds straight upwards from its displaced base (15c) (refer Fig. 3). Given the important requirement of providing rigidity and strength to the curved flap (15), the curved flap (15) so provided, can also proceed upwards with a positive or negative inclination instead proceeding straight upwards while following this condition. The curved flap (15) of the dust seal (100) so created would be curved along more than one axis which would provide it with a structure more capable of resisting any loads applied on it. As the curved flap (15) is a portion of the dust seal (100) having limited thickness and weight, structural strength it has is primarily required only for facing rare impacts from stones and/or foreign flying objects hitting it on its outer surface (15a).

[0030] The dust seal (100) has a plurality of equally spaced openings (25) on the curved flap (15) with said openings (25) being in the same horizontal plane on the projecting curved flap (15). The plurality of equally spaced openings (25) are profiled to have conical cross section projecting inside (25a) towards the hollow conical top body (45) at the inner face (15b) of the curved flap (15) that direct air onto the outer curved surface of the hollow conical top body (45) (refer Figs. 3 and 5). These conical projections have air passage carved through it and the said air passage has the diameter converging towards the inner side thus making the venture effector for the passage of air. The plurality of equally spaced openings (25) have a profile selected from a set of rectangular slits, said slits inclined right, inclined left and/or combination thereof, and said profiles are configured to have converging cross section projecting inside (25a) towards the hollow conical top body (45) at the inner face (15b) of the curved flap (15) (refer Figs. 1, 3, 6, 7, 8, 9, 10 and 11). Hence, the inner profile of the openings (25) is such that it enables utilization of venturi effect to direct the air at higher speed creating an air jet directed onto the outer curved surface of the hollow conical top body (45). The plurality of equally spaced openings (25) are angularly displaced from the plurality of equally spaced openings (35) such that when the dust seal (100) is viewed from the top, the plurality of equally spaced flap surface opening (25) do not lie along the same imaginary line proceeding outwards from the center of the circular opening (45aa). Not having the openings (25 and 35) directly above one another enables the air flowing through the openings (25) to take a curved path around the hollow conical top body (45) without having its energy dissipated immediately by the flow that is occurring via the openings (35).

[0031] Equally spacing the openings (25) on the curved flap (15) helps in better managing the negative effect that providing them has on the strength of the curved flap (15). The openings (25) circulate air when the vehicle is moving thereby helping in removal of foreign objects from the portion where the curved flap (15), the hollow cylindrical base (5) and the hollow conical top body (45) join together. The secondary purpose of providing the openings (25) is to facilitate cooling of the inner tube (110T) in the area immediately behind the curved flap (15).

[0032] The dust seal (100) also has a plurality of equally spaced openings (35) along the joint between the hollow cylindrical base (5) and the curved flap (15) on the displaced base (15c) of the curved flap (15). The joint between the hollow cylindrical base (5) and the curved flap (15) on the displaced base (15c) is incidentally one portion of the dust seal (100) that is on an average thicker other portions of the dust seal (100). Providing some equally spaced openings (35) in this location therefore does not compromise the overall strength of the dust seal (100). The openings (35) provide a clear pathway for facilitating outflow of any fluid (most commonly mud) that might get accumulated during vehicle operation. Working together with the openings (25), the openings (35) ensure that most foreign objects never settle down along the joint between the hollow cylindrical base (5) and the curved flap (15) on the displaced base (15c).

[0033] The hollow cylindrical base (5) has a thick annular ring (5a) on its inside curved surface along the lower edge. The thick annular ring (5a) has a top flat surface (5aa), a middle cylindrical curved surface (5ab) and a lower surface (5ac). The lower surface (5ac) is slopped in an outward direction to facilitate easy mounting of the dust seal (100) onto a groove (110aa) given on the front fork outer tube (110) (refer Figs. 3, 5, 8, 11). The thick annular ring (5a) allows the dust seal (100) to be mounted in a groove given on the outer surface of the outer tube (110) (refer Fig. 12) of the front fork suspension. The thick annular ring (5a) also has a projection (5ad) that rotationally locks the dust seal (100) to a matching recess (110ab) given on the front fork outer tube (110).

[0034] The hollow conical top body (45) has an inside lower flat surface (45ac) that forms the upper boundary of the hollow cylindrical base (5) on the inside curved surface. The hollow conical top body (45) has an inwardly curved profile with a circular opening (45aa) on its top. The hollow conical top body (45) has an inner lip (45c) along the upper opening (45aa) and an inner lip (45d) below the inner lip (45c) separated by a curved surface (45cd). The inner lip (45d) forms the upper edge of an inside curved surface (45ab) and the inside lower flat surface (45ac) forms the lower edge of the inside curved surface (45ab) (refer Figs. 3, 5, 8, 11). The curved surface (45cd) provided between the inner lips (45c and 45d) is a feature which works to enhance the functioning of the inner lips (45c and 45d). The structure formed by the curved surface (45cd) is sufficient flexibility to hold and eject substances accumulated within the space given between it and the inner tube (110T) during the upward and downward movement of the inner tube (110T).

[0035] The hollow conical top body (45) is profiled to have a lower outer portion (45L) having steeper slope than its top outer portion (45U). The hollow conical top body (45) is hence provided with the required inclined/curved structure that is effective in handling loads that might be applied on the dust seal (100) by the inner lips (45c and 45d).
[0036] The dust seal (100) so disclosed when mounted onto the outer tube (110) of the front fork (refer Fig. 12) functions to protect the inner tube (110T) from being hit by foreign objects in the entire area lying behind the curved flap (15). The dust seal (100) also functions to prevent ingestion of foreign objects into the front fork via its inner lips (45c and 45d). The dust seal (100) further has openings (25 and 35) which work to prevent accumulation of foreign objects thereby reducing the possibility of them scratching the outer surface of the inner tube (110T). The dust seal (100) requires no metallic reinforcement to be provided within it as its structure gives it sufficient rigidity and strength to perform its functions.

[0037] Thus, the novelty of the dust seal (100) resides in the hollow conical top body (45) joined to the hollow cylindrical base (5) to form an integral unit and the curved flap (15) is formed with the said unit along the joint of the hollow conical top body (45) and the hollow cylindrical base (5) in such way that the curved flap (15) is projected vertically and displaced outside the outer surface of the hollow cylindrical base (5) in the radial direction of the said hollow cylindrical base (5). The dust seal (100) has a plurality of equally spaced openings (25) on the curved flap (15) and the said openings (25) are in the same horizontal plane on the projecting curved flap (15). The openings (25) are profiled to have conical cross section projecting inside (25a) towards the top conical body (45) at the inner face (15b) of the curved flap (15) that creates an jet directing onto the outer curved surface of the hollow conical top body (45). These novel and inventive features of the dust seal (100) contribute to the technology domain of the dust seals and also impart technical advantages as discussed above. Additionally the technical advantages derived from the invention are as under. Thus, the invention qualifies the test of inventive step also.
- The dust seal of the invention does not require metallic reinforcement to achieve the required strength and rigidity.
- It can be easily manufactured in very few steps given that it does not require any embedded reinforcement, thus reducing the cycle time of its manufacturing.
- It has a curved flap which is capable of functioning as an impact protector, thus eliminating the requirement of separate and dedicate impact protector.
- It has features that allow foreign objects to be removed from in between the dust seal and the impact protector before they accumulate and become cause of damage to the surface of the inner tube of the front fork.
- It secondarily functions to allow cooling of the inner tube by allowing air to flow from within its openings towards the curved surface of the inner tube.
- The openings given on curved flap of the dust seal are perfectly positioned with respect to the openings given on the displaced base to maximize the advantage obtained by air flowing through them.
- The openings given on the curved flap are profiled to the maximize airflow for removing foreign objects and also cool the inner tube by effectively creating a venturi effect.
- The curved flap (15) protects a wide surface area of the inner tube from getting hit by foreign objects.

[0038] The number of openings that can be provided on the dust seal can be changed by altering the strength and hardness of the material used for making the dust seal. The limiting condition being that the dust seal must still have sufficient flexibility to be pushed onto and mounted into the groove given on the outer surface of the outer tube of the front fork. Any such alterations would be obvious to a person skilled in the art and must hence not be seen to be lying outside the scope of the described invention.

[0039] The foregoing description of the specific embodiments 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. 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.