FORM 2
The Patents Act 1970
(39 of 1970)
&
The Patent Rules 2003
COMPLETE SPECIFICATION
(See Section 10 and rule 13)
TITLE OF THE INVENTION:


AIR VALVE EJECTOR SYSTEM FOR COMPRESSION MOULD
APPLICANT:
LARSEN & TOUBRO LIMITED
L&T House, Ballard Estate, P.O. Box No. 278,
Mumbai, 400 001, Maharashtra . INDIA.
PREAMBLE OF THE DESCRIPTION:
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

A)TECHNICAL FIELD
[0001] The present invention generally relates to molding of plastic objects and particularly to provide an ejector for ejecting the molded plastic object from the mould and more particularly it relates to provide an air valve ejector system for ease of ejection of thermoset plastic and to avoid vacuum creation on the punch.
B) BACKGROUND OF THE INVENTION
[0002] Thermoset molded articles are used extensively in everyday life. Thermoset are cross linked polymeric materials which get desired shape by the apphcatiou of heat and pressure. The mould apparatus can be designed to any required shape and used repeatedly to manufacture copious amounts of molded articles. Various molding methods are used to manufacture articles using moulds of required shape and size.
[0003] Compression mould is a tool used to produce thermo set plastic molded component in large quantities on the compression-molding machine. It is available in different tonnage and sizes to make variety of components. The mould design is made to suit the molding machine and the plastic material processing condition. Mould construction includes two halves fix half and moving half. Fix half is clamped on the stationary platen of the machine, moving half is clamped on the moving half of the machine. It also includes an ejector assembly to eject the component.

[0004] Furthermore, all thermoset plastic materials contract as they solidify, which means that the molding shrinks on to the punch which forms it. This shrinkage makes the molding difficult to remove. It is normal practice, therefore, to provide some means by which the molded part can be positively ejected from the punch. The ejection of the component can be done using ejector pin. stripper plate, stripper bar, air valve and sleeve ejector etc. Usually in the component, there will be some rectangular pocket features which are very deep. These pockets will form the vacuum during ejection of component from the punch side. Therefore, there is a need to provide an air valve ejector system to eject the component.
[0005] The conventional air valve ejectors are difficult for manufacturing and fitting on the punch, particularly on the taper area of the punch. By analyzing the air valve ejector system designs thoroughly, we realized that, there is a need to develop an air valve ejector system with respect to ease of manufacturing and assembly. More over, in earlier design the air passage way is achieved by machining slot into the shank of the valve. Hence there is a need to eliminate the slot manufacturing on the periphery of the shank. Hence there is a need to provide an air valve ejection system which can be easily manufactured and assembled.
C) OBJECTS OF THE INVENTION


[0006] The primary object of the present invention is to provide an air valve ejection system for ease of ejection of molded thermoset plastic and to avoid vacuum creation on the punch.
[0007] Yet another object of the present invention is to provide an air valve ejector system for ease of manufacturing and assembly with the punch.
[0008] Yet another object of the present invention is to provide an air valve ejector system which can be directly assembled in mould without the need of taper matching between valve and punch.
[0009] Yet another object of the present invention is to provide an air valve ejector system with simple drilled holes in air ejector retainer to avoid machining of slot on the shank of valve as in traditional air valve ejector system.
[0010] These and other objects and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.
D) SUMMARY OF THE INVENTION
[0011] The above mentioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and studying the following specification.


[0012] The various embodiments of the present invention provide an air valve ejector system which can be directly assembled on the mould without the need of taper matching between the valve and a punch. The air valve ejector system comprises of four parts namely an air ejector valve, an air ejector retainer, air ejector housing and a spring.
[0013] According to embodiment of the present invention, the air ejector system includes an air ejector valve surrounded by an air ejector retainer. To provide passage for the compressed air, small holes are drilled in air ejector retainer. The air ejector valve is held on to its seating by means of compression spring. This later member is held in position by using a nut. To prevent the loss of compressed air from the rear side, air ejector housing is incorporated from the top. The subassembly of air valve ejector system can be separately assembled on mold without the need of taper matching between the valve and punch.
[0014] According to embodiment of the present invention, the air valve ejector assembly is directly assembled on the mould without any taper matching between the valve and punch. The mould is loaded on the compression molding machine. After all the required setting to run the mould is completed, top half of the machine moves forward and butte against the bottom half of the mold. After completion of the component curing, mould opens. During mould opening, the air is passed through the channel. Due to air pressure, the spring compresses and valve moves ahead and ejects the component. The valve sits in its position by means of the spring pressure. The air valve ejector system in the present

indention also helps in removing the air from deep pocket on punch side. In compression mould design, the air valve ejector system is used for ease of ejection of molded plastic and to avoid vacuum creation on punch. Hence by providing simple drilled holes in air ejector retainer, the air ejector system is easier in machining compared to traditional air valve ejector system. The manufacturing and assembling of the air valve ejector system is very easy.
E) BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiment and the accompanying drawings in which:
[0016] FIG .1 shows a cross sectional assembled view of the air valve ejector system according to one embodiment of the present invention.
[0017] FIG. 2 shows a cross sectional partial assembly of the compression mould top half and bottom half in close condition.
[0018] Although specific features of the present invention are shown in some drawings and not in others. This is done for convenience only as each feature may be combined with any or all of the other features in accordance with the present invention.

F) DETAILED DESCRIPTION OF THE INVENTION
[0019] In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which the specific embodiments that may be practiced is shown by way of illustration. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments and it is to be understood that the logical, mechanical and other changes may be made without departing from the scope of the embodiments. The following detailed description is therefore not to be taken in a limiting sense.
[0020] The various embodiments of the present invention provide an air valve ejector system which can be directly assembled on the mould without the need of taper matching between the valve and a punch. The air valve ejector system comprises of four parts namely an air ejector valve, an air ejector retainer, air ejector housing and a spring.
[0021] FIG .1 shows a cross sectional assembled view of the air valve ejector system 100 according to one embodiment of the present invention. The air ejector system 100 consists of an air ejector valve 101 surrounded by an air ejector retainer 102. To provide passage for the compressed air, small holes are drilled in air ejector retainer 102. The ejector valve 101 is held on to its seating.by means of compression spring 103. This later member of air ejector valve 101 is held in position by a nut 104. To prevent the loss of compressed air from the rear side, an air ejector housing 105 is incorporated from the top.

Tihe subassembly of air valve ejector system can be separately assembled on mold without the need of taper matching between valve and punch.
[0022] FIG. 2 shows a cross sectional partial assembly of the compression mould top half and bottom half in close condition. With respect to figure 2, the air valve ejector assembly 100 is directly assembled on the mould without any taper matching between the valve and the punch. The mould is loaded on the compression molding machine. After all the required setting to run the mould is completed, top half 201 of the machine moves forward and butte against the bottom half 202 of the mold. After completion of the component curing, mould opens. During mould opening, the air is passed through the channel. Due to air pressure, the spring compresses and valve moves ahead and ejects the component. The valve sits in its position by means of the spring pressure. The air valve ejector system 100 in the present invention also helps in removing the air from deep pocket on punch side. In compression mould design, the air valve ejector system is used for ease of ejection of molded plastic and to avoid vacuum creation on punch.
G) ADVANTAGES OF THE INVENTION
[0023] The various embodiments of the present invention provide an air valve ejector system which can be directly assembled on the mould without the need of taper matching between the valve and a punch. It provides an improved design of valve, by removing slot manufacturing on periphery of the shank. It provides simple drilled holes in air ejector retainer and hence avoids machining of slots on the shank of the valve as in


traditional air valve ejector. The air valve ejector system is designed to ensure ease of manufacturing and assembly with the punch.
[0024] Although the invention is described with various specific embodiments, it will be obvious for a person skilled in the art to practice the invention with modifications. However, all such modifications are deemed to be within the scope of the claims.

RAKESH PRABHU
Patent Agent
[0025] It is also to be understood that the following claims are intended to cover all of the generic and specific features of the present invention described herein and all the statements of the scope of the invention which as a matter of language might be said to fall there between.
Date: March 30, 2009. Place: Bangalore.

CLAIMS
What is claimed is:
1. An air valve ejector system for compression moulding machine comprising:
an air ejector housing;
an air ejector valve arranged inside the air ejector housing; an air ejector retainer arranged to surround the air ejector valve; pluralities of springs arranged above the air ejector valve; and a nut arrangement provided above the pluralities of springs; wherein small holes are drilled in the air ejector retainer.
2. The system according to claim 1, wherein the air retainer is provided inside the housing to surround the air ejector valve.
3. The system according to claim 1, wherein the air ejector valve is provided in the mould without performing the taper matching between the valve and the punch in the mould.
4. The system according to claim 1, wherein the pluralities of springs are provided above the air ejector valve to hold the valve in the given place in the mould.
5. The system according to claim 1, wherein the pluralities of springs are compression springs.
3 1 MAR 2009

6. The system according to claim 1, wherein the compression springs are held in the given position by the nut and bolt arrangement.
7. The system according to claim 1, wherein the holes are drilled in the air ejector retainer to provide a passage for the compressed air.
Dated this the 30th day of March 2009

RAKESH PRABHU Patent Agent,
ALMT Legal,
#2, Lavelle Road, Bangalore-560 001
To,
The Controller of Patents. The Patent Office, Mumbai