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:
SIDE CORE ACTUATION ASSEMBLY FOR INJECTION
MOULDING DEVICE
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 injection moulding and particularly to multi cavity injection moulds with side cores on multiple sides. The present invention more particularly relates to releasing undercuts of moulded components for ejection from the moulding apparatus.
B) BACKGROUND OF THE INVENTION
[0002] Thermoplastic moulded articles are used extensively in everyday life. Thermoplastics are linear or branched polymeric materials which melt when heated and resolidify when cooled. Mould apparatus can be designed t6 any required shape and used repeatedly to manufacture copious amounts of moulded articles. Various moulding methods are used to manufacture articles using mould of required shape and size. Injection moulding is used to manufacture articles of different shapes and sizes ranging from small components to automobile body panels.
[0003] In injection moulding process thermoplastic raw materials are heated to melting point and forced under pressure into a cold mould. Injecting components force the melted liquid into the mould to cool and solidify. Injection moulding machine comprises of a fixed half and a moving half. The fixed half is secured to the stationary platen of the injection moulding machine. The moving half or core half is secured to the moving platen of the injection moulding machine. The fixed half of the machine comprises of a nozzle aligned to the sprue to fill the melted raw material to the cavity in the fixed and the moving half. Mould ejecting mechanism provided on the moving half of the machine
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removes the moulded component from the moulding apparatus provided in the moving half.
[0004] The die cavity designed to form the required article is provided in the fixed and moving halves of the apparatus. The moving half is aligned to the fixed half to form the shape of the required moulded component. The melted plastic is injected through feed system arrangement of the apparatus into the cavity. The melted plastic cools and solidifies to form the required moulded component.
[0005] The moulded component remains in the half with the ejector components because of the shrinkage property of the plastics. The ejector pins are used to push the moulded component from the apparatus. The undercuts in the line of draw should be released before ejection of the moulded component.
[0006] The undercuts are released using additional designs in the apparatus. The mould may be opened in multiple layers. Additional release surfaces may be provided to slide and release external undercuts using various actuation mechanisms including mechanical, hydraulic and pneumatic methods. Internal undercuts may be released using various methods including collapsible cores or internal slides. Double ejection method may be used to activate ejector plates sequentially to relieve the surface around the undercut to expand and eject the moulded component.
[0007] Currently various methods are adopted to actuate side cores in multi cavity moulds. The mould assembly accommodates the multi-cavity construction, side cores and actuation mechanisms. Conventional actuation components include dogleg cam, finger

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cam and hydraulic cylinder. The inclusion of actuation components increases the size of the mould. However, moulding using conventional actuation methods can be achieved only in higher machines involving high production cost. Hence there is a need to provide an actuation method to reduce the mould size for multi cavity moulds.
C) OBJECTS OF THE INVENTION
[0008] The primary object of the present invention is to provide a side core actuation system and method for a multi cavity mould with external undercuts.
[0009] Another object of the present invention is to provide a side core actuation system with a single element for movement and wedging the mould.
[0010] Yet another object of the present invention is to provide a side core actuation system to reduce the size of the mould.
[0011] Yet another object of the present invention is to provide a cost effective side core actuation mechanism.
[0012] 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
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[0013] The above mentioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and studying the following specification.
[0014] The various embodiments of the present invention provide a system and method to actuate a multi cavity mould. The mould has external undercuts on plurality of sides. A cam is secured to the fixed half of the mould and the side core is secured to the moving half. A dove tail slot is provided on the side core with a tapering surface. The cam is provided with mating tapered surface to engage the dove tail slot of side core. The dove tail on side core is interlocked to the mating tapered surface on cam. The side core moves towards the cam on taper when the mould opens. The movement of side core releases the undercuts of the component. The moulded component is ejected from the moulding apparatus.
[0015] 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.
E) BRIEF DESCRIPTION OF THE DRAWINGS
[0016] 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:
[0017] FIG. 1 illustrates the sectional view of the mould assembly according to one embodiment of the present invention.
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[0018] FIG. 2A illustrates the side sectional views of side core with tapered dove tail slot in mould assembly according to one embodiment of the present invention.
[0019] FIG. 2B illustrates the top view of side core with tapered dove tail slot in the mould assembly according to one embodiment of the present invention.
[0020] FIG. 3A illustrates the side perspective view of a cam in the mould assembly according to one embodiment of the present invention.
[0021] FIG. 3B illustrates the top view of the cam in the mould according to one embodiment of the present invention.
[0022] FIG. 4 illustrates a side view of side core and cam interlock in the mould assembly according to one embodiment of the present invention.
[0023] FIG. 5 illustrates a side view of releasing interlock between side core and cam according to one embodiment of the present invention.
[0024] 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 INVENTION
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[0025] 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.
[0026] The various embodiments of the present invention provide a system and method to actuate a multi cavity mould. The mould has external undercuts on plurality of sides. A cam is secured to the fixed half of the mould and the side core is secured to the moving half. A dove tail slot is provided on the side core with a tapering surface. The cam is provided with mating tapered surface to engage the dove tail slot of side core. The dove tail on side core is interlocked to the mating tapered surface on cam. The side core moves towards the cam on taper when mould opens. The movement of side core releases the undercut of the component. The moulded component is ejected from the moulding apparatus. The same cam pushes the side cores to take back the position to form the shape of component and wedges the side core against injection pressure when the mould closes.
[0027] FIG. 1 illustrates the sectional view of the mould assembly according to one embodiment of the present invention. Cams 11 are secured to fixed half 10 of the mould assembly. Side cores 1 are secured to moving half 20 of the mould assembly. The tapered dove tail slot of side cores 1 are interlocked to mating tapered dove tail of cams 11.
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[0028] FIG. 2A illustrates the sectional view of side core with tapered dove tail slot. The side core 1 is provided with tapered dove tail slot 3. The tapered dove tail surface 2 is interlocked to mating tapered dove tail surface of cam.
[0029] FIG. 2B illustrates the top perspective view of side core with tapered dove tail slot. The side core 1 is provided with tapered dove tail slot 3. The tapered dove tail surface 2 is interlocked to mating tapered dove tail surface of cam.
[0030] FIG. 3A illustrates the side perspective view of cam 11. The cam 11 comprises of opposite surfaces with dove tail tapering 12. The tapering surface 12 may be interlocked to mating dove tail tapering on side core.
[0031] FIG. 3B illustrates the top perspective view of cam 11. The cam 11 comprises of opposite surfaces with dove tail tapering 12. The cam 11 is fixed to fixed half 10 of the mould assemblv.
[0032] FIG. 4 illustrates a side view of side core and cam interlock according to one embodiment of the present invention. The tapered surface 2 in the dove tail slot 3 is interlocked to mating tapered surface 12 of cam 11. The side core 1 and cam 11 are interlocked by the mating tapering surfaces when the mould assembly is closed. This provides wedging of side core against injection pressure.
[0033] FIG. 5 illustrates a side view of releasing interlock between side core and cam according to one embodiment of the present invention. The side core 1 moves towards cam 11 when the mould assembly is opened. The side core 1 slidably detaches the tapering surface 2 in dove tail slot 3 from mating tapering surface 12 of cam 11.
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[0034] The external undercuts of moulds are released to eject the moulded component from the mould assembly.
G) ADVANTAGES OF THE INVENTION
[0035] Thus the various embodiments of the present invention provide a system and method for side core actuation in injection moulds. Since actuation and wedging is done by the same member,the size of the mould is reduced for multi cavity moulds by dove tail design for actuation components. Tapered dove tail construction by itself requires only small space compared to other construction, which reduces mould size. The size of mould with external undercuts in multi cavity moulds is reduced to suit lower machines. The cost of production of mould is reduced.
[0036] 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.
[0037] 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. RAKESH PRABHU
Place: Bangalore. Patent Agent


CLAIMS
What is claimed is:
1. a side core actuation assembly for injection molding device including a fixed half
and moving half, the assembly comprising:
a side core secured to the moving half
a dove tail cam secured to the fixed half; and
a dove tail slot formed on the side core;
wherein the dove tail cam is engaged with dovetail slot to interlock the side core
with the cam during the opening and closing of the mold.
2. The assembly according to claim 1, wherein the dove tail cam has a tapered surface.
3. The assembly according to claim 1, wherein the dovetail slot has a tapered surface.
4. The assembly according to claim 1, wherein the tapered surface of the dovetail slot is mated with the tapered surface of the dovetail cam, when the dovetail cam is engaged with the dovetail slot on the side core to lock the side core.
5. The assembly according to claim 1, wherein the side core is moved towards the cam during the opening of the mold and side core is moved away from the cam
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during closing and provides wedging for sid core since the dovetail cam is locked with dovetail slot.
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

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