FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION (See section 10 and rule 13)
1. TITLE OF THE INVENTION
"Floating Valve Piston System"
2. APPLICANT
(a) NAME : GABRIEL INDIA LIMITED
(b) NATIONALITY: An Indian Company registered under the provisions of
The Companies Act, 1956
(c) ADDRESS : 29th, Milestone, Pune Nasik Highway,
Village: Kuruli, Tal: Khed,
Dist: Pune-410 501 (MH)
COMPLETE
The following specification
particularly describes the invention and the
manner in which it is to be performed.

Floating Valve Piston System
Field of the invention
The present invention relates to a floating valve piston system, and more particularly, to the floating valve piston system for a shock absorber used in vehicles.
Background of the invention
A shock absorber is a mechanical device designed to smooth out or damp shock impulse, and dissipate kinetic energy. Shock absorber is an important part of automobile and motorcycle suspensions. Generally, in shock absorbers, a piston and valve system controls motion of a hydraulic fluid such as oil along a tube or a pipe by means of a linear motion of the piston within a chamber or a cylinder.
Referring to figure 1, a prior art shock absorber (1) is shown. The shock absorber (1) comprises an inner tube (2), an outer tube (3), a movable piston assembly (4) connected at one end of a piston rod (5) and a base valve assembly (6). The movable piston assembly (4) includes a piston (7) that divides the inner tube (2) into a rebound chamber (8) and a compression chamber (9).
The oil flow mechanism with respect to a compression stroke and a rebound
stroke can be understood as follows.
Oil flow mechanism in compression stroke
In shock absorbers, during compression stroke when the piston moves from a lop dead center (hereinafter referred as TDC) to a bottom dead center (hereinafter referred as BDC), the oil flows through outer holes in the piston. On the opposite side of the piston, a non-return valve covers the outer holes. Subsequently, the flow of oil forces the non-return valve to lift against a non-return spring. Thus, the valve lifts to allow the oil to flow past.

Oil flow mechanism in rebound stroke
During rebound stroke, at low velocities, the oil flows past the piston through the tension holes. On the opposite side of the piston, there is a notched valve; which sits on a two valve-seating surfaces. Oil entering through the tension holes in the piston fills up the volume between the valve-seating surfaces and the notched valve. Then, the oil flows out through the notches in the notched valve. At medium velocities, oil force pushes the deflection discs. The discs bend 10 allow oil to flow. At high velocities,the tension holes in the piston acts as the restriction to oil flow thereby creating tension damping.
The suspension system and rebound damping force development mechanism of the prior art in its construction requires piston that is manufactured by sintered process using a composite material, which is a critical process and the cost of the sintered material is also high. Also, the manufacturing process requires high accuracy for the piston that makes the system costly.
Accordingly, there exists a need to provide a floating valve piston system for shock absorbers that overcomes drawbacks of the prior art.
Object of the invention
An object of the present invention is to provide a floating valve piston system for shock absorbers that develops a rebound mechanism with less accuracy parts and is easy to manufacture.
Summary of the invention
Accordingly, the present invention provides a floating valve piston system for a shock absorber. The floating valve system comprises a piston ring, a piston guide. a valve spring, a valve pack assembly, a bolt piston, a piston cup. a hex nut. a valve stopper, a nut stopper and a guide nut. The valve pack assembly comprises a metering spacer, a plurality of deflection discs, a valve seat and a plurality of back

up discs. The floating valve system is mounted on a piston rod to move in an axial direction in an inner tube of the shock absorber. The inner tube of the shock absorber includes a top chamber and a bottom chamber. The piston rod reciprocates axially in the inner tube and holds the piston and the valve pack assembly.
The piston ring acts as a seal between the top chamber and the bottom chamber. The piston guide includes a plurality of first set of orifices that allows oil flow during suspension travel. The piston guide is provided with a slot to hold the piston ring.
The metering spacer is provided with a plurality of notches and a plurality of second set of orifices. The metering spacer controls low velocity damping by allowing only a certain volume of oil to flow through the second set of orifices thereof. The valve seat provides a seat to the deflection discs.
The valve spring is pushed by the valve pack assembly against the piston guide thereby allowing the oil flow during compression. The bolt piston holds the valve pack assembly with the guide nut. The piston cup with a seat acts as a seating surface for the valve pack assembly and as a base for the valve stopper. The hex nut locks the valve pack assembly onto the piston rod and the nut stopper provides a surface for tightening the guide nut.
Brief description of the drawings
Figure 1 is a cross sectional view of a shock absorber, in accordance with the prior art;
Figure 2 shows an exploded view of a floating valve piston system, in accordance with the present invention;

Figure 3 shows a cross-sectional view of the shock absorber with an oil flow mechanism in a compression stroke, in accordance with the present invention; and
Figure 4 shows a cross-sectional view of the shock absorber with the oil flow mechanism in a rebound stroke, in accordance with the present invention.
Detailed description of the invention
The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiments.
Accordingly, the present invention provides a floating valve piston system for shock absorbers used in vehicles. The floating valve piston system of the present invention is easy to manufacture as compared to the sintered piston system of the prior art. Further, the floating valve piston system develops a rebound mechanism with less accuracy parts.
The 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.
An existing amplitude selective shock absorber of a suspension system includes an inner tube, an outer tube, a stationary piston valve, a piston rod, a floating piston valve system and a base valve assembly. The stationary piston valve is mounted on the piston rod and divides the inner tube into a top chamber and a bottom chamber, wherein the top chamber represents a rebound chamber and the bottom chamber represents a compression chamber. The above mentioned parts are described in the figure 1 of the prior art and are not described again herein in detail for the sake of brevity of the disclosure.

In accordance with the present invention, the floating valve piston system is characterized in that the floating valve piston system (hereinafter referred as 'the system (200)') comprises a piston ring (10), a piston guide (20), a valve spring (30), a valve pack assembly (not numbered), a bolt piston (70), a piston cup (80). a hex nut (90), a valve stopper (100), a nut stopper (110) and a guide nut (120). The valve pack assembly includes a valve seat (40). a metering spacer (50). a plurality of deflection discs (60) and a plurality of back up discs (130). In an embodiment, the deflection discs (60) are also known as plate valves.
Now describing the figure 2 in conjunction with figure 1 the system (200) is mounted on the piston rod (5) to move in an axial direction in the inner tube (2). The piston rod (5) axially reciprocates in the inner tube (2) and holds the piston (7) and the valve pack assembly. The piston ring (10) acts as a seal between the rebound chamber (8) and the compression chamber (9) in the inner tube (2) of the suspension assembly.
The piston guide (20) is provided with a plurality of first set of orifices (not shown) that allow oil flow during suspension travel. Further, the piston guide (20) is provided with a slot to hold the piston ring (10). The piston guide (20) acts as a base for the piston cup (80). The piston cup (80) holds the valve pack assembly.
The valve spring (30) is pushed by the valve pack assembly against the piston guide (20) thereby allowing the oil flow during compression. During tension, the valve spring pushes (30) the valve pack assembly against the piston cup (80) thus acting as a check valve,
The valve seat (40) provides a seat to the deflection discs (60). The volume between the valve-seating surfaces and the metering spacer (50) is used as a reservoir during tension at low velocities. The metering spacer (50) is provided with a plurality of notches (not shown) and a plurality of second set of orifices (not shown). The metering spacer (50) controls low velocity damping by allowing

only a certain volume of oil to flow through the second set of orifices thereof. Hence, the outer diameter and the notched area of the metering spacer (50) are critical.
The bolt piston (70) holds the valve pack assembly with the guide nut (120). During compression, the bolt piston (70) along with the valve pack assembly lifts against the spring force allowing the oil flow. The piston cup (80) with a seat acts as a seating surface for the valve pack assembly and also acts as a base for the valve stopper (100). The valve stopper (100) includes a plurality of notches (not numbered). The hex nut (90) is tightened on the valve stopper (100). The hex nut (90) locks the valve pack assembly onto the piston rod (5). The hex nut (90) is tightened to a set torque limit.
The nut stopper (110) provides a surface for tightening the guide nut (120) as the guide nut (120) should not be tightened against the deflection discs (60) surface. The flatness of the surface that faces the deflection discs (60) is controlled to ensure that the valves sit properly. The backup discs (130) provide the cantilever point for the deflection discs (60) to bend. The thickness and outer diameter of the backup discs (130) are critical as the outer diameter determines the bending point.
Referring now to figure 3, there is shown a cross-sectional view of the shock absorber with an oil flow mechanism in a compression stroke, in accordance with the present invention. Specifically, the figure 3 shows a mechanism (300). The mechanism (300) is now described in conjunction with the system (200). The mechanism (300) involves lifting the valve pack assembly against the valve spring (30) due to oil pressure shown as (A). In the compression stroke, as the system 200 moves from a top dead center (hereinafter referred as TDC) to a bottom dead center (hereinafter referred as BDC) of the shock absorber, the oil also flows past the valve stopper (100) through the notches thereof. On the opposite side of the valve stopper (100), the oil flow is resisted by the valve seat (40) and the How of

oil forces the valve pack assembly including the valves and valve seal (40) to lift against the spring force. Thus, the valve seat (40) lifts to allow the oil to flow past.
Referring now to figure 4, there is shown a cross-sectional view of the shock absorber with the oil flow mechanism in a rebound stroke in accordance with the present invention. Specifically, the figure 4 shows a mechanism (400). The mechanism (400) is now described in conjunction with the system (200).The mechanism (400) involves bending of the deflection discs (60) due to oil pressure shown as (B). At low velocities, the oil flows past the piston guide (20) through the first set of orifices. On the opposite side of the piston guide (20), the metering spacer (50) sits on the valve seat (40). The oil coming out of the valve seat (40) fills up the volume between the valve-seating surfaces and the metering spacer (50). Then, the oil flows out through the plurality of notches of the metering spacer (50). At medium velocities, the oil force pushes the deflection discs (60. 120) that bend to allow oil to flow. At high velocities, the holes in the piston guide (20) and the valve seat (40) act as the restriction to oil flow thereby creating tension damping.
Advantages of the invention
1. The system (200) develops the rebound mechanism with less accuracy parts.
2. The system (200) requires low part accuracy and general manufacturing process that reduces the cost.
3. The system (200) is easily scalable to any bore diameter 025 and above.
4. The system (200) is easy to manufacture.
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed. and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order lo best explain the principles of the present invention and its practical application, to thereby enable

others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of / equivalents are contemplated as circumstance may suggest or render expedient. but such are intended to cover the application or implementation without departing from the spirit or scope of the present invention.

We Claim:
1. A floating valve piston system for a shock absorber having an inner tube, an outer tube, a stationary piston valve, a piston rod, and a base valve assembly. wherein the stationary piston valve is mounted on the piston rod and divides the inner tube into a top chamber and a bottom chamber, the system comprising:
a piston ring that acts as a seal between the top chamber and the bottom chamber in the inner tube;
a piston guide having a plurality of first set of orifices that allow oil flow during suspension travel thereby creating a damping effect, the piston guide is provided with a slot to hold the piston ring;
a valve pack assembly having,
• a metering spacer that includes a plurality of second set of orifices, the metering spacer controls low velocity damping by allowing only a certain volume of oil to flow through the second set of orifices thereof.
• a plurality of deflection discs,
• a plurality of back up discs that provide a cantilever point for the deflection discs to bend, and
• a valve seat that provides a seat to the deflection discs, wherein the valve pack assembly along with the piston is held by the piston rod;
a valve spring that allows the oil flow during compression by pushing the valve pack assembly against the piston guide;
a bolt piston that holds the valve pack assembly with a guide nut;
a piston cup with a seat acts as a seating surface for the valve pack assembly and as a base for a valve stopper;
a hex nut that locks the valve pack assembly onto the piston rod: and
a nut stopper that provides a surface for tightening the guide nut.

2. The floating valve piston system as claimed iii claim 1. wherein the metering spacer and the valve stopper is provided with a plurality of notches.
3. The floating valve piston system as claimed in claim I. wherein the deflection discs bend to allow oil flow at medium velocities.