FORM 2 THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION:
Improvements in or relating to automatic decompressor
2. APPLICANT
(a) NAME: ADVIK HI-TECH PVT LTD
(b) NATIONALITY: Indian Company
(c) ADDRESS: Gat No. 357/99, Chakan Talegaon Road,
Village Kharabwadi, Chakan, Tal. Khed, Pune -410501, Maharashtra India
3. PRREAMBLE TO THE DESCRIPTION
COMPLETE The following specification particularly describes the invention and the manner in which it is to be performed.

IMPROVEMENTS IN OR RELATING TO AUTOMATIC DECOMPRESSOR
FIELD OF INVENTION
[001] The present invention relates to an improvement in an automatic decompressor design and operating mechanism. More specifically, the present invention is related to an automatic decompressor designed to be used in an internal combustion engine assembly.
BACKGROUND OF INVENTION
[002] The internal combustion engine generally includes a decompressor which operates a valve at low engine speeds to relieve compression within one or more engine cylinders during the compression stroke of the engine cycle. [003] In general decompressors have been developed selectively for actuating exhaust valve to reduce the compression pressure in a combustion chamber while starting the engine. Such devices relieve the pressure of exhaust gases within an engine combustion chamber. By relieving exhaust gases, it is much easier for the piston to reciprocate in the engine when an operator manually kicks start the motor cycle or two-wheeler. Thus, a decompressor and/or compression release mechanism lowers the pull force required to kick start the engine. As a result, the impending operator lassitude during the starting of the ride is also minimized.

[004] Despite of the various advancement offered by the technology, there is a
need of improvement particularly in the decompressor design (as the directed in
the prior art shown in FIG. 1).
[005] Description of the prior art: The existing construction of extension
spring type auto decompressor unit as shown in FIG. 1, includes an extension
spring 108 assembled in base plate 102 between slot 104b and other end in 104a
of arm 104. The other end 104a of spring is floated along with arm 104. The
cam 110 and the arm 104 are linked with the help of a roller 112. The arm 104 is
fixed on base plate 102 through a shaft 106.
[006] One recognized problem with the said spring is that it has limitation of
no. of turns and outer diameter. It is studied that the arm weight requires less
than maximum working load of spring.
[007] Further, another problem is arisen with the one fixed arm of the spring.
Because of this, the maximum load of arm impacts only on one fixed arm of
spring. When rpm of cam shaft increases, the floated arm floats towards the
outside. As the rpm decreases, it comes at the initial position. In above said
process the repeatability of opening and closing do not occur at the specified
rpm because the floated end of the spring is one side from maximum load of
arm.
[008] Furthermore, in an idle condition of engine, the arm will be in close
condition and releases the residual gas from the combustion chamber. During
the working of engine when rpm of cam shaft increases up to a specified limit,
that time the arm will start floating towards the outer side continuously. In this

case, due to the variation is rpm, a variation of time in opening and closing the arm is detected. In repeated process, the more load of arm is at the one side from spring floating end, the arm partially opens in close condition instead of being fully closed and similarly, it will open at a specified rpm instead of the idle condition.
[009] Hence, there is a necessity for control weight of arm as compared to the spring load. Further, it is required to devise a decompressor and a decompressing mechanism that can overcome one or more limitations of the prior art.
SUMMARY OF THE INVENTION
[010] Accordingly, an auto decompressor unit of an internal combustion engine is disclosed. The auto decompressor unit comprises a base plate, a floating arm fixed on the base plate through a shaft, a spring comprising two lugs, wherein, one lug is fixed in a slot of the base plate 202 and other lug is fixed in end hole of the floating arm, and a cam linked with the floating arm with the help of a roller. In the embodiment, the cam rotates when the floating arm floats towards the outer & inner side (open & close condition) at a specified rpm, and an exhaust valve of the internal combustion engine operates to release the exhaust gases. As the rpm of the cam shaft increases the floating arm floats towards the outer side, and at idle condition the arm comes in the initial (inner) position.

[Oil] It is an object of the present invention to provide an auto decompressor unit that includes a single spring that's one lug is fixed in a slot of the base plate 202 and other lug in end hole of the floating arm.
[012] In another embodiment of the present invention, the auto decompressor unit comprises two stoppers and a designed slot for mounting the spring. In the embodiment, the cam has "D" shape at the end.
[013] It is another object of the present invention to provide a component assembly for reducing the compression of an internal combustion engine. The component assembly comprises a camshaft; a base plate secured to, and rotating with, the camshaft, a shaft which is rotatably supported in the base plate and which has a cam formed thereon, and a floating arm which is attached with the base plate through a single spring so as to be subject to centrifugal force on rotation of the camshaft.
[014] It is a further object of the present invention to provide an operating mechanism to reduce the variation in rpm (min to Max) rpm. The operating mechanism comprises sliding the cam beyond the edge outside of an exhaust valve to open the corresponding exhaust valve in order to reduce the compression of the engine when the rotational speed of the camshaft is less than speed of reverse engine movement, and pulling the cam below to the edge of the exhaust valve to close the corresponding exhaust valve during the compression stroke of the engine when the rotational speed exceeds the speed of reverse engine movement.

[015] Some of all aforementioned advantages of the present invention are considered by placing a single spring in such as a way that it eliminates the need of maintaining the ratio of weight of floating arm and load of the spring. Thus, with the designed introduced in present invention capable of working for any weight of the floating arm.
BRIEF DESCRIPTION OF DRAWINGS
[016] The detailed description is described with reference to the accompanying
figures. In the figures, the same numbers are used throughout the drawings to
reference identical features and/or components.
[017] FIG. 1 represents an auto decompressor assembly in accordance with a
prior art;
[018] FIG. 2 represents an auto decompressor in accordance with an
embodiment of the present invention, and
[019] FIG. 3 represents an auto decompressor in accordance with another
embodiment of the present invention.
DETAILED DESCRD7TION OF THE INVENTION
[020] The instant disclosure is provided to further explain the best modes of performing one or more embodiments of the present invention. The disclosure is further offered to enhance an understanding and appreciation for the inventive principles and advantages thereof, rather than to limit in any manner the invention. The invention is defined solely by the appended claims including any

amendments made during the pendency of this application and all equivalents of
those claims as issued. It is noted that some embodiments may include a
plurality of processes or steps, which can be performed in any order, unless
expressly and necessarily limited to a particular order; i.e., processes or steps
that are not so limited may be performed in any order.
[021] Accordingly, referring to FIG. 2 an improved auto decompressor 200 is
provided.
[022] In an embodiment of the present invention, the auto decompressor unit
200 comprises a base plate 202. Over the base plate 202 all the child parts are
assembled. The child parts include a floating arm 204, shaft 206, a spring 208,
cam arm 210 and roller 212.
[023] The floating arm 204 is fixed on base plate 202 through the shaft 206. In
an embodiment of the present invention, the fixing is done by the clinching
process. The spring 208 has two lugs; one lug is fixed in a slot of the base plate
202 and other end in end hole of the floating arm 204. The cam 210 and the
floating arm 204 are linked with the help of a roller 212.
[024] In base plate 202, there are two stoppers, one is 202a and other is 202b.
Also there is slot 202c for mounting. Cam 210 rotates when the floating arm 204
floats at outer & inner side (open & close condition) at a specified rpm.
[025] In an embodiment of the present invention, the cam 210 has "D" shape at
the end. With the help of this cam 210, the gasses will be released in combustion
chamber. As the rpm of the cam shaft increases, the floating arm will float
towards the outer side and at idle condition arm will cdme in the initial position.

[026] One or more advantages of the present invention are accrued by the decompression mechanism by which the flyweight will open on time and there will be no delay in the opening of flyweight. With the present design of the auto decompressor 200, a higher rpm can be achieved as compared to the existing prior arts. Furthermore, such design enables the decompressor to eliminate the weight limits consideration of arm as compared to the spring. Further, in such single spring design, the spring 208 can be of less stiffness. It is also helpful in eliminating the stuck problem of arm by improving the spring placement in the spring 208. The spring 208 is enabled to sustain the maximum weight of arm due to the spring placement. Hence, less weight of arm will work and there will be no dependency on maximum working load of spring.
[027] In FIG. 2, the auto decompressor unit 200 is shown when the floating arm is inner side on the base plate 202 and the exhaust valve is in closed condition.
[028] In FIG. 3, the auto decompressor unit 200 is shown when the floating arm is outer side on the base plate 202 and the exhaust valve is in open condition.
[029] Another embodiment of the present invention provides a component assembly for reducing the compression of an internal combustion engine. The component assembly comprises a camshaft, a base plate secured to, and rotating with, the camshaft, a shaft which is rotatably supported in the base plate and which has a cam formed thereon, and a floating arm which is attached with the

base plate through a single spring so as to be subject to centrifugal force on rotation of the camshaft.
[030] In an embodiment of the present invention, the component assembly is being operated in accordance with an operating mechanism. The operating mechanism states that the cam 210 goes beyond the edge outside of the exhaust valve to open the corresponding exhaust valve in order to reduce the compression of the engine when the rotational speed of the camshaft is less than speed of reverse engine drive, and the cam 210 is pulled below to the edge of the exhaust valve to close the corresponding exhaust valve during the compression stroke of the engine when the rotational speed exceeds the speed of reverse engine drive.
[031] In the embodiment the operating mechanism is provided to reduce the variation in rpm (min to max rpm). For example, in the existing decompressor assemblies, the rpm variation is high. The present invention is capable of reducing variation than existing decompression. In an embodiment of the present invention, the auto decompressor unit includes a single spring that is arranged at an end of floating arm and fixed in a slot of the base plate in such a way that it eliminates the need of maintaining the ratio of the weight of floating arm and load of the spring. Thus, with the designed introduced in present invention capable of working for any weight of the floating arm. [032] The invention is applicable primarily to compression ignition or gasoline and/or diesel engines in which the combustion chamber is separate from the cylinder clearance space and is connected thereto by a narrow passage.

[033] This disclosure is intended to explain how to fashion and use various embodiments in accordance with the invention rather than to limit the true, intended, and fair scope and spirit thereof. The foregoing description is not intended to be exhaustive or to limit the invention to the precise form disclosed. Modifications or variations are possible in light of the above teachings. The embodiment(s) was chosen and described to provide the best illustration of the principles of the invention and its practical application, and to enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated.

We Claim:
1. An auto decompressor unit of an internal combustion engine comprising;
a base plate;
a floating arm arranged on the base plate through a shaft;
a spring comprising two lugs, wherein, one lug is fixed in a slot of the base plate and other lug is fixed in an end hole of the floating arm, and
a cam linked with the floating arm with the help of a roller wherein the cam rotates when the floating arm floats at outer & inner side (open &,close condition) at a specified rpm thereby operating on an exhaust valve of the internal combustion engine to release the exhaust gases with the rotation of said cam.
2. The auto decompressor unit as claimed in claim 1 wherein the base plate comprises two stoppers and a designed slot for mounting the spring.
3. The auto decompressor unit as claimed in claim 1, wherein the cam has "D" shape at the end.
4. The auto decompressor unit as claimed in claim 1, wherein the floating arm floats towards the outer side as the rpm of the cam shaft increases, and at idle condition the floating arm comes in the initial position.

5. The auto decompressor unit as claimed 1, where the spring is mounted on the base plate in accordance with the FIG. 2.
6. A component assembly for reducing the compression of an internal combustion engine, the component assembly comprising:
a camshaft;
a base plate secured to, and rotating with, the camshaft;
a shaft which is rotatably supported in the base plate and which has a cam formed thereon, and
a floating arm engaged to float corresponding to the base plate through a spring that comprises two lugs, wherein, one lug is fixed in a slot of the base plate and other lug is fixed in an end hole of the floating arm.
a cam linked with the floating arm with the help of a roller wherein the cam rotates when the floating arm floats at outer & inner side (open & close condition) at a specified rpm thereby operating on an ■exhaust valve of the internal combustion engine to release the exhaust gases with the rotation of said cam.
7. The component assembly as claimed in claim 6, wherein the
component assembly is operated in accordance with an operating
mechanism to reduce rpm variation, the operating mechanism
comprising:
sliding the cam beyond the edge outside of an exhaust valve to open the corresponding exhaust valve in order to reduce the compression

of the engine when the rotational speed of the camshaft is less than speed of reverse engine movement, and
pulling the cam below to the edge of the exhaust valve to close the corresponding exhaust valve during the compression stroke of the engine when the rotational speed exceeds the speed of reverse engine movement.