FORM 2
THE PATENT ACT, 1970,
(39 OF 1970)
&
THE PATENTS RULE, 2003
COMPLETE SPECIFICATION
(SEE SECTION 10; RULE 13)
"CAM SHAFT TO CAM SHAFT CHAIN DRIVE SYSTEM IN ENGINE"
MAHINDRA & MAHINDRA LIMITED
AN INDIAN COMPANY,
R&D CENTER, AUTOMOTIVE SECTOR,
89, M.I.D.C, SATPUR,
NASHIK-422 007,
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:-
The present invention is related to drive system in the engine assembly. More particularly the present invention is related to cam shaft to cam shaft drive system by a secondary chain to have low noise in the engine assembly.
DETAILED DESCRIPTION OF THE PRESENT INVENTION:
The present invention presents an innovative concept of cam shaft to cam shaft drive by a secondary chain to have low noise. Intake camshaft is driven by a primary chain getting drive from crankshaft and exhaust camshaft is driven by secondary chain getting drive from intake camshaft. Separate hydraulic tensioners available for tensioning chain in primary chain drive and secondary chain drive.
BRIEF DESCRIPTION OF THE FIGURES:-
Figure 1 shows the perspective view of the cam shaft to cam shaft drive system by secondary chain in accordance with the present invention.
Figure 2 shows the front view of the cam shaft to cam shaft drive by secondary chain in accordance with the present invention.
Figure 3 shows the assembly view of the cam shaft to cam shaft drive by secondary chain as per the present invention.
The cam shaft to cam shaft drive system by employing secondary chain as per the present invention comprises of following elements.
Camshaft: Shaft that consists of the lobes used for actuation of valves
Exhaust camshaft: Shaft that consists of the lobes used for actuation of exhaust valves.

Intake camshaft: Shaft that consists of the lobes used for actuation of intake
valves
Sprocket: Toothed wheel over which chain is wrapped
Primary sprocket: Sprocket that is mounted on intake camshaft and taking drive from crankshaft via chain
Hydraulic tensioner: A system for giving tension to the chain on it's slack side with the help of pressurized oil.
Tensioner arm: Provides a sliding surface for chain and rotates about a point to tension the chain.
Fixed guide: Provides a sliding surface for chain without any rotation.
Crank sprocket: Sprocket that is mounted on crank shaft
Primary drive: This drive consists of all the parts that are present in driving the intake camshaft by chain from crankshaft. Namely, primary chain, crank sprocket, primary sprocket, hydraulic tensioner - primary, tensioner arm, fixed guide.
Secondary drive: This drive consists of all the parts that are present in driving exhaust camshaft by chain from intake camshaft. Namely, intake sprocket, exhaust sprocket, hydraulic tensioner- secondary, secondary chain.
Referring to Figure 3, cam shaft to cam shaft drive system comprises of intake cam shaft, exhaust cam shaft, intake sprocket, exhaust sprocket, secondary chain, hydraulic tensioner secondary drive, primary sprocket, primary chain, crank sprocket, hydraulic tensioner primary drive with tensioner arm. The intake sprocket is mounted over the intake cam shaft and exhaust sprocket is mounted over the exhaust cam shaft. The primary sprocket and intake sprocket are mounted on the same shaft. The crank sprocket and primary sprocket are in

communication with each other through the primary chain drive wherein fixed guide and tensioner arm are provided for smooth functioning of the system. Intake sprocket and exhaust sprocket are in communication with each other through secondary chain drive. The secondary chain drive system is supported with hydraulic tensioner secondary drive for the smooth functioning of the system. The drive communication between intake and sprocket and exhaust sprocket by the secondary chain drive system which is supported with the hydraulic tensioner is the unique feature of the system.
THE TECHNICAL ADVANTAGES ACHIEVED BY THIS SYSTEM ARE AS UNDER:-
1. It's a low noise system as the camshafts are driven by chain.
2. Cost of the system is low compared to a gear drive system
3. Chain noise is always within tolerance band. If it is a gear drive, back lash, gear teeth quality are difficult to control which will influence the noise radiated from the drive and it's never within the limits specified.
4. Moreover if gear drive is used rubberisation of the gear will be required to reduce the noise radiation, which is costly but not durable.
5. Also the noise levels of rubberized gears are high compared to a chain driven camshaft.

WE CLAIM:-
1. Cam shaft to cam shaft drive system comprising of intake cam shaft, exhaust cam shaft, intake sprocket, exhaust sprocket, secondary chain, hydraulic tensioner secondary drive, primary sprocket, primary chain, crank sprocket, hydraulic tensioner primary drive with tensioner arm wherein the intake sprocket is mounted over the intake cam shaft and exhaust sprocket is mounted over the exhaust cam shaft; the primary sprocket and intake sprocket are mounted on the same shaft.
2. Cam shaft to cam shaft drive system by using secondary chain drive as claimed in claim 1 wherein the crank sprocket and primary sprocket are in communication with each other through the primary chain drive wherein fixed guide and tensioner arm are provided for smooth functioning of the system; and intake sprocket and exhaust sprocket are in communication with each other through secondary chain drive wherein the secondary chain drive system is supported with hydraulic tensioner secondary drive for the smooth functioning of the system.
3. Cam shaft to cam shaft drive system by using secondary chain drive as claimed in claim 1 wherein primary sprocketis mounted on intake camshaft and takes the drive from crankshaft via chain.
4. Cam shaft to cam shaft drive system by using secondary chain drive as claimed in above claims wherein hydraulic tensioner provides tension to the chain on it's slack side with the help of pressurized oil; and tensioner arm provides a sliding surface for chain and rotates about a point to tension the chain.
5. Cam shaft to cam shaft drive system by using secondary chain drive as claimed in above claims wherein primary drive comprises of primary chain, crank sprocket, primary sprocket, hydraulic tensioner - primary, tensioner arm, fixed guide; and secondary drive comprises of intake

sprocket, exhaust sprocket, hydraulic tensioner - secondary, secondary chain.