FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION:
"Dual Spring Shock Absorber"
2. APPLICANT
(a) NAME: Gabriel India Limited
(b) NATIONALITY: Indian National
(c) ADDRESS: 29th, Milestone, Pune Nasik Highway,
Village : Kuruli, Tal: Khed, Dist: Pune-410 501 (MH)
3. PRREAMBLE TO THE DESCRIPTION
COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

Dual spring Shock Absorber
Field of the invention
The present invention relates to shock absorbers, and more particularly, the present invention relates to an improved dual spring shock absorber, for example a hydraulic twin tube, monotube, canister type shock absorber and the like.
Background of the invention
A shock absorber is a mechanical device designed to smooth out or damp shock impulse, and dissipate kinetic energy. Improvement in the normal shock absorber for two-wheeler with a single spring is an dual spring shock absorber which includes two springs located in series (end-to-end) to support a load. These dual spring shock absorber provides better suspension to a rider as compared to normal single spring shock absorber.
One such dual spring shock absorber available currently includes two springs (2, 3) guided by a spring guide (1) as shown in figure 1A of the prior art. The spring guide moves along the damper body as shown in the figure 1 A. However, the spring guide (1) rubs against the damper body which can cause rusting of the damper. Further, the spring guide (1) wears due to rubbing on the damper body.
Another dual spring shock absorber of the prior art as shown in figure IB includes a dust seal (1) in between a spring guide (5) and a damper body. Also, the shock absorber of figure 2 includes a dry bearing (2). Though the shock absorber of figure 2 provides better suspension, use of the dust seal and the dry bearing makes the shock absorber costly.

Yet another shock absorber of the prior art as shown in figure 1C, includes a spring guide (1) mounted on a spring locator (2), However, if sand particles/hard particles trap in between the spring guide (1) and the spring locator (2), these parts wears due to abrasion. Further, there is very low heat dissipation.
Still another shock absorber of the prior art as shown in figure ID, includes a spring guide (1) mounted on a spring locator (2). In this type of design, a lower and an upper springs should be of same inner and outer diameter. If these diameters are different then upper spring will not be guided by the spring locator.
Accordingly, there exist a need to provide a shock absorber for better suspension, which overcomes drawbacks of the prior art.
Objects of the invention
An object of the present invention is to provide a dual spring shock absorber having the parts which do not wear due to continuous abrasion.
Another object of the present invention is to provide dual spring shock absorber which has high heat dissipation.
Summary of the invention
Accordingly, the present invention provides a dual spring shock absorber assembly for a vehicle, the shock absorber assembly comprising:
a first cylindrical tube having oil/gas therein to generate tension/compression damping;
a second cylindrical tube reciprocatably secured with the first cylindrical tube;

a lower spring disposed over the first cylindrical tube;
an upper spring disposed over the second cylindrical tube, the upper spring communicating with the lower spring, characterized in that,
a spring guide freely placed between the lower spring and the upper spring, the spring guide having a seating for receiving lower end portion of the upper spring and upper end portion of the lower spring, the spring guide capable of guiding the lower spring at an outer diameter of the first cylindrical tube and the upper spring at an outer diameter of the second cylindrical tube, wherein the spring guide moves along and allows the upper spring and lower spring to compress at a time; and
a spring locator mounted on the first cylindrical tube, the spring locator capable of guiding the lower spring at inner diameter thereof, wherein the spring locator restrict buckling of the lower spring,
wherein upon receiving load, the upper spring and the lower springs compress at a time till the lower spring becomes solid, thereafter the spring guide allows the upper spring and the lower springs' compression at a time and the upper spring with higher rate start compressing.
Brief description of the drawings
Figure 1A, IB, 1C and ID shows dual spring shock absorbers of the prior art;
Figure 2 A and 2B shows a cross sectional view of a dual spring shock absorber, in accordance with the present invention;
Figure 3 A and 3B shows a spring guide of the dual spring shock absorber of figure 2 A and 2B; and
Figure 4 A and 4B shows a spring locator of the dual spring shock absorber of figure 2A and 2B.

Detailed description of the invention
The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the preferred embodiment.
The present invention provides a dual spring shock absorber assembly. The dual spring shock absorber assembly includes parts which do not wear due to continuous abrasion. Further, the dual spring shock absorber assembly has high heat dissipation.
This 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 bracket in the following description.
Referring now to figure 2A and 2B, there is shown a cross sectional view of a dual spring shock absorber assembly (hereinafter 'the assembly (100)'), in accordance with the present invention. Specifically, figure 2A and 2B shows the assembly (100). The assembly (100) includes a first cylindrical tube (10), a second cylindrical rod (20), a lower spring (30), an upper spring (40). The improvement in the assembly (100) comprises a spring guide (50) and a spring locator (60).
The first cylindrical tube (10) includes oil/gas therein to generate tension/compression damping. Further, the second cylindrical rod (20) is reciprocatably secured with the first cylindrical tube (10).
A top portion of the second cylindrical rod (20) includes a top mounting element (22) secured thereto and a bottom portion of the first cylindrical tube (10) includes a bottom mounting element (12) secured thereto.

In an embodiment, the first and the second cylindrical tubes (10 and 20) may be of any shape obvious to a person skilled in the art.
The lower spring (30) is disposed over the first cylindrical tube (10), and the upper spring (40) is disposed over the second cylindrical tube (20). The upper spring (40) communicates with the lower spring (30).
The improvement in the assembly (100) comprises the spring guide (50) and the spring locator (60).
The spring guide (50) is freely placed between the lower spring (30) and the upper spring (40). The spring guide (50) is a circular member covering an outer periphery of the first cylindrical tube (10) as shown in figure 3 A and 3B. The spring guide (50) includes a seating (52) for receiving lower end portion (42) of the upper spring (40) and upper end portion of the lower spring (32). The spring guide (50) is movable with lower spring (30) and upper Spring (40).
The spring guide (50) is capable of guiding the lower spring (30) at an outer diameter of the first cylindrical tube (10) and the upper spring (40) at an outer diameter of the second cylindrical tube (20). The spring guide (50) moves along the upper spring (40) and the lower spring (30) and allows the upper spring (40) and the lower spring (30) to compress at a time.
Further, the spring locator (60) is mounted on the first cylindrical tube (10). The spring locator (60) is capable of guiding the lower spring (30) at inner diameter thereof. Specifically, the spring locator (60) is elongated tubular member as shown in figure 4A and 4B. The spring locator (60) includes a outward flange (62) covering a periphery of one end portion thereof. The outward flange (62) supports

the lower spring (30) thereon. The spring locator (60) restrict buckling of the lower spring (30). Specifically, the lower spring (30) buckles due to stroking up to solid length at every stroke and the spring locator (60) restrict bucking of the lower spring (30), thus helps to improves the fatigue life of the lower spring (30).
When a vehicle, for example, a motorcycle hit a bump, a tire moves up and shock absorber spring compresses. In dual springs shock absorber assembly (100), the lower spring (30) and the upper spring (40) are assembled in series. As per the spring in series formula, initially both the lower and the upper spring (30, 40) compress at a time till the lower spring (30) with lower spring rate becomes solid. The movable spring guide (50) allows both spring compression at a time. After the lower spring (30) get solid, the upper spring (40) with higher rate start compressing.
Advantages of the invention
L The assembly (100) do not cause wear or rust problem as spring guide does not rub with spring locator or the shock absorber body.
2. The assembly (100) causes no spring buckling of the lower spring (30) as the spring locator (60) guides the lower spring during stroking.
3. The assembly (100) can use different inner diameter and outer diameter of lower and upper springs (30,40).
4. The assembly (100) allows the lower spring (30) and the upper spring (40) to move at the same time without affecting the mating parts in terms of wear and rust.
The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by

the present invention described in the present embodiment. Detailed descriptions of the preferred embodiment are provided herein; however, it is to be understood that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure, or matter. The embodiments of the invention as described above and the methods disclosed herein will suggest further modification and alterations to those skilled in the art. Such further modifications and alterations may be made without departing from the spirit and scope of the invention.

We Claim
1. A dual spring shock absorber assembly for a vehicle, the shock absorber
assembly comprising:
a first cylindrical tube having oil/gas therein to generate tension/compression damping;
a second cylindrical tube reciprocatably secured with the first cylindrical tube;
a lower spring disposed over the first cylindrical tube;
an upper spring disposed over the second cylindrical tube, the upper spring communicating with the lower spring, characterized in that,
a spring guide freely placed between the lower spring and the upper spring, the spring guide having a seating for receiving lower end portion of the upper spring and upper end portion of the lower spring, the spring guide capable of guiding the lower spring at an outer diameter of the first cylindrical tube and the upper spring at an outer diameter of the second cylindrical tube, wherein the spring guide moves along and allows the upper spring and lower spring to compress at a time; and
a spring locator mounted on the first cylindrical tube, the spring locator capable of guiding the lower spring at inner diameter thereof, wherein the spring locator restrict buckling of the lower spring,
wherein upon receiving load, the upper spring and the lower springs compress at a time till the lower spring becomes solid, thereafter the spring guide allows the upper spring and the lower springs' compression at a time and the upper spring with higher rate start compressing.
2. The shock absorber assembly of claim 1, wherein top portion of the second
cylindrical tube includes a top mounting element secured thereto.

3. The shock absorber assembly of claim 1, wherein bottom portion of the first cylindrical tube includes a bottom mounting element secured thereto.