FORM 2
THE Patent Act, 1970
(39 of 1970)
&
The Patent Rules, 2003
COMPLETE SPECIFICATION
(See Section 10 and Rule 13)
Suspension system for three wheeler
Endurance Technologies Pvt Ltd R&D, E 93, MIDC Industrial Area, Waluj, Aurangabad, Maharashtra-431136
The following specification describes the invention

Field of the invention
This invention relates to a suspension system for three wheeler, and more particularly, the invention relates to a shock absorber for a three wheeler with a damping adjustment.
Description of the prior art
Suspension system comprising shock absorbers are used in vehicles to dampen inputs from roadways. For some vehicle applications, such as three wheelers, it may be highly desirable to provide the ability to easily adjust the damping characteristics of a shock absorber basing on the load the vehicle is carrying. For example, three wheeler ride characteristics may be affected due to the variation of weight from different and multiple passengers or due to weight of the goods. The greater the vehicle's and passenger's static weight, the more the shock absorber will become compressed thereby lessening its damping capability. To this end, adjustable shock absorbers have been developed to permit the driver to adjust the damping characteristics of the shock absorber to accommodate varying weights and personal vehicle handling preferences.
A of typical construction a variable damping force shock absorber has been disclosed in US 4913255 as well as CN 203189598. The variable damping force shock absorber has a damping characteristics adjusting mechanism which adjusts damping characteristic of the shock absorber irrespective of the stroke direction. Such prior proposed variable damping force shock absorber is not yet complete for achieving satisfactorily level of riding comfort and vehicular driving stability particularly for three wheeler applications.
Therefore, it is an object of the present invention to provide an automotive suspension system which assures good riding comfort with a sufficient level of driving stability.

In order to ensure riding comfort and driving stability in a three wheeler suspension system, the effect of the damping force generated by the suspension system must be observed and taken into account. For instance, if the damping characteristics of the suspension system is so hard that it tends to amplify vibrations of the suspension system, the damping characteristics must be softened to provide a satisfactory level of riding comfort. Therefore, the present invention for three wheelers provides an automotive suspension system that has variable damping characteristics which depend on the nature of the damping force produced in response to bounding and/or rebounding motion of the vehicle so as to optimize damping characteristics to achieve both riding comfort and driving stability.
Brief description of the invention
According to one embodiment of the present invention, an adjuster mechanism is provided for suspension system having shock absorber for a three wheeler. The adjuster mechanism comprises an adjuster connected to a threaded pulley arrangement which is further connected to a cam through connecting cables. The rotation of the cam is controlled by a torsion spring. The torsion spring is provided to manage the cam mechanism of the cam effectively. When the adjuster is positioned suitably according to the user requirement of the three wheeler, the cable is pulled and it further rotates the pulley accordingly which further rotates the cam. As the cam moves, the movement of the needle is controlled which influences the orifice for damping control. This action happens simultaneously on both the rear wheel shock absorbers of the three wheeler. As a result of the action of the adjuster, damping control is performed in for the rear shock absorbers of the three wheeler. According to another embodiment of the present invention, another adjuster mechanism is provided for shock absorber for a three wheeler. The adjuster mechanism comprises an adjuster connected to a cam with a wedge profile through connecting cables. The movement or

progression/ regression of the cam is controlled by a compression spring. When the adjuster is positioned suitably according to the user requirement of the three wheeler, the cable pulls the cam accordingly. As the cam is pulled, the movement of the needle is controlled which influences the orifice for damping control. This action happens simultaneously on both the rear wheel shock absorbers and of the three wheeler. As a result of the action of the adjuster, damping control is performed in for the rear shock absorbers of the three wheeler.
Brief description of the drawings
The present invention will be understood more fully from the detailed description given here below and from the accompanying drawings of the preferred embodiment of the invention, which, however, should not be taken to limit the invention to the specific embodiment but are for explanation and understanding only.
In the drawings:
Figure 1 is a section of preferred embodiment of a variable damping force shock absorber according to the present invention
Figure 2 is an enlarged section of the major part of the preferred embodiment of the variable damping force shock absorber, according to the invention;
Figure 3 is a section of a second embodiment of a variable damping force shock absorber according to the present invention
Figure 4 is an enlarged section of the major part of second embodiment of the variable damping force shock absorber, according to the invention;

Detailed description of the invention
Referring now to the drawings, particularly to FIG. 1 and Figure 3, the preferred embodiment of a suspension system having a shock absorber, according to the present invention, serves as a principle component of the preferred embodiment of an automotive suspension system. The shown shock absorber 100 comprises variable damping characteristics.
A piston assembly 4 is disposed within the internal space of the cylinder tube 3 for dividing the internal space into upper and lower working chambers 14 and 15. The piston assembly 4 is supported on the lower end of a piston rod 6. The piston rod 6 is guided by a rod guide 8 which is engaged in the top end opening of the cylinder tube 3. The rod guide 8 cooperates with a piston seal 9 and a stopper plate 10 to form an upper plug assembly for sealingly closing the top ends of the cylinder 3.
The top end of the piston rod 6 is connected to a vehicle body (not shown) in a per se known manner. On the other hand, a connecting eye 32 with an eye bushing 31 is provided on the lower end of the tube 3. The cylinder tube 3 is connected to a suspension member (not shown) rotatably supporting a road wheel. The shock absorbers 100 and 200 are thus disposed between the vehicle body and the suspension member to receive vibration energy causing relative displacement between the vehicle body and the suspension member. The shock absorbers 100 and 200 are compressed in response to a bounding stroke motion, in which the vehicle body and the suspension member are shifted to approach to each other, and expanded in response to a rebounding stroke motion, in which the vehicle body and suspension member are shifted away from each other. In response to the bounding stroke motion of the vehicle body and the suspension member, the piston assembly 4 strokes in a compression stroke direction while compressing the lower working chamber 15. This causes the working fluid pressure in the lower working chamber to increase and

the working fluid pressure in the higher working chamber to decrease. On the other hand, in response to the rebounding stroke motion of the vehicle body and the suspension member, the piston assembly 4 strokes in the expansion stroke direction while compressing the higher working chamber 14. Therefore, the fluid pressure in the upper working chamber 14 is increased and the fluid pressure in the lower working chamber 15 is decreased.
The piston assembly 4 is designed to vary the damping characteristics to generate the damping force in response to the vibration input according to the variable characteristics in a different damping mode. In order to control the damping mode of the piston assembly 4, an adjustment mechanism 700 is connected to the piston assembly via a needle 35 which extends through the piston rod. The adjustment mechanism 700 provides variability to the typical type of shock absorber which employs piston and cylinder assembly having higher 14 and lower 15 working chambers of variable volume which are connected by an orifice 36 through which hydraulic fluid is displaced. In such a device, the cross sectional area of this orifice 36 determines the force exerted by the shock absorber in resistance to the pressure force created in one of the chambers as a result of relative motion between the vehicle body and the wheels.
Thus the shock absorbers (100 and 200) are set at a compromise point on the hardness/softness spectrum so that it is less than ideal for achieving both objectives of vibration isolation and inertial resistance. Further, the shock absorbers (100 and 200) resistive force (which is proportional to the pressure drop across the orifice) is proportional to the flow rate through the orifice 36 present on the sleeve 38, which varies positively with the input pressure—i.e., the shock absorber hardens as input pressure increases and softens as it decreases. However, in the present invention the control maneuver through the needle 35 constantly change the area of the inter-chamber orifice 36 through which the hydraulic fluid in the piston/cylinder assembly flows in response to wheel and body

movements. These changes adjust the shock absorber's point on the hardness/softness spectrum to that which is the most appropriate for the conditions at each moment.
According to one embodiment of the present invention (Figure 1 & Figure 2), an adjuster mechanism 700 is provided for suspension system with shock absorber for a three wheeler. The adjuster mechanism comprises an adjuster 70 connected to a threaded pulley 71 arrangement which is further connected to a cam 72 through connecting cables 79. The rotation of the cam 72 is controlled by a torsion spring 73. The torsion spring 73 is provided to manage the cam mechanism of the cam 72 effectively. When the adjuster 70 is positioned suitably according to the user requirement of the three wheeler, the cable 79 is pulled and it further rotates the pulley 71 accordingly which further rotates the cam 72. As the cam 72 moves, the movement of the needle 35 is controlled which influences the orifice 36 for damping control. This action happens simultaneously on both the rear wheel shock absorbers 100 and 200 of the three wheeler. As a result of the action of the adjuster, damping control is performed in for the rear shock absorbers of the three wheeler.
According to another embodiment of the present invention, (Figure 3 & Figure 4), another adjuster mechanism is provided for suspension system with a shock absorber for a three wheeler. The adjuster mechanism comprises an adjuster 70 connected to a cam 75 with a wedge profile through connecting cables 79. The movement or progression/ regression of the cam 75 is controlled by a compression spring 76. When the adjuster 70 is positioned suitably according to the user requirement of the three wheeler, the cable 79 pulls the cam 75 accordingly. As the cam 75 is pulled, the movement of the needle 35 is controlled which influences the orifice 36 for damping control. This action happens simultaneously on both the rear wheel shock absorbers 100 and 200

of the three wheeler. As a result of the action of the adjuster, damping control is performed in for the rear shock absorbers of the three wheeler.
The both the embodiments illustrated above, said adjuster 70 of the adjuster mechanism has plurality of pre-designed slots for covering various load conditions of the three wheeler for ensuring riding comfort and driving stability. The adjuster 70 can be placed at any suitable location of the three wheeler for ease of access.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the invention. These and other changes in the preferred embodiment as well as other embodiments of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be.interpreted merely as illustrative of the invention and not as a limitation.

Claims
We claim:
1. A suspension system for three wheeler comprising:
at least two shock absorbers with needles controlling the opening of inter-chamber orifice between upper and lower working chamber; and
an adjuster mechanism connected to each of said shock absorbers, said adjustment mechanism movable between a plurality of positions corresponding to said plurality of damping requirement for damping control in each of said shock absorbers.
2. The suspension system for three wheeler as claimed in claim 1, wherein said adjuster mechanism comprises a single adjuster, connected with cams with threaded pulley on each shock absorber, and said cams movement being controlled with a torsion spring.
3. The suspension system for three wheeler as claimed in claim 1, wherein said adjuster mechanism comprises a single adjuster, connected with cams having wedge profile on each shock absorber, and said cams movement being controlled with a compression spring.
4. The suspension system for three wheeler as claimed in claim 1, wherein said adjuster can be mounted on any suitable location of the vehicle.
5. The suspension system for three wheeler as claimed in claim 1, wherein said adjuster of said adjuster mechanism has plurality of pre-designed slots for covering various load conditions of the three wheeler