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:
FLOATING INSERT 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 device and particularly to ejection mechanism for moulded articles. The present invention more particularly relates to ejection mechanism for ejecting moulded articles with internal undercuts.
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 to any required shape and used repeatedly to manufacture copious amounts of moulded articles. Various moulding methods are used to manufacture articles using moulds 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 cold mould. Injecting components force the melted liquid into the mould to cool and solidify. Injection molding apparatus 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 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 half. Mould ejecting mechanisms


provided on the moving half of the machine remove the moulded component from the molding apparatus.
[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 plastics. The ejector pins are used to push the moulded component from the apparatus. The undercuts in the line of draw are 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.
[0007] 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 components. However the current methods to eject internal undercuts are expensive and complex. The additional ejection components to relieve the undercuts require various associated mechanisms to actuate the components. The maintenance of the components is


difficult. Hence there is a need to provide a simple, efficient and cost effective method to relieve internal undercuts for ejection of moulded articles.
C) OBJECTS OF THE INVENTION
[0008] The primary object of the present invention is to develop a floating insert assembly for an injection moulding device to eject the moulded component with internal undercuts safely without distortion while ejecting it forcefully to jump out of the undercuts.
[0009] Another object of the present invention is to develop a floating insert assembly for an injection moulding device to eject the moulded component with internal undercuts while retaining the impression shape of the undercut.
[0010] Yet another object of the present invention is to provide a compact and simple ejection mechanism in injection moulding apparatus thereby eliminating the need for a double ejection mechanism
[0011] Yet another object of the present invention is to develop a floating insert assembly for an injection moulding device to eject the moulded component with internal undercuts and to reduce the manufacturing cost of the components.
[0012] Yet another object of the present invention is to develop a floating insert assembly which is dismantled and maintained easily in an injection moulding apparatus.


[0013] 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
[0014] The above mentioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and studying the following specification.
[0015] The various embodiments of the present invention provide a floating insert assembly for an injection moulding device to eject the molded components with internal undercut. According to one embodiment of the present invention, the floating insert assembly has a floating insert in which undercut of the component is machined. The insert is coupled to a pull back pin through a dowel. The pullback pin is extended beyond the ejection plates. Another dowel is provided at the bottom end of the pin. The component with internal undercut is ejected safely using the floating insert mechanism. The features in the component around the undercut are allowed to expand to eject the component with internal under cut forcefully. The floating insert is coupled to the ejection plate. The ejection plate coupled to ejection pins and floating insert is actuated to eject the component. The floating insert is gripped by the internal undercut of the component. The floating pin moves with the ejection plates when the mould is opened and the ejector plate is activated by a machine rod which pushes the component outwardly along with the floating insert. After a certain length of stroke the floating pin is stopped from moving further, and by this time the external surface of under cut surface is out of the punch insert and will give relieve to flex outside and jump out of undercut.


The component is further ejected out with ejector pins as the stroke of ejector plate continues. The Floating punch is brought back into its position by the pull back pin which is activated by return back movement of the ejector plates to repeat the cycle.
[0016] The external surface of undercut surface is relieved from the punch insert. The external surface flexes outside the punch insert to relieve the undercut. The moulded component is ejected from the injection moulding apparatus. The pullback pin coupled to the floating pin is actuated to retrace the movement by the reverse movement of the ejector plate.
[0017] 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
[0018] 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:
[0019] FIG. 1 illustrates the sectional and enlarged views of the floating insert assembly in an injection molding apparatus and the according to one embodiment of the present invention.
[0020] FIG. 2 illustrates the side view of the moulded component with internal undercut.


[0021] FIG. 3 illustrates the sectional view of the floating insert assembly in moulding apparatus during the mould opened condition according to one embodiment of the invention.
[0022] FIG. 4 illustrates the movement of floating insert and ejector pins together in the injection moulding apparatus during ejection stroke according to one embodiment of the present invention.
[0023] FIG. 5 illustrates the disengagement of internal undercut from floating pin in the floating insert assembly in the injection moulding apparatus on further advancement of ejection unit according to one embodiment of the present invention.
[0024] FIG. 6 illustrates the position of the floating insert assembly after the ejection of moulded component in the injection moulding apparatus according to one embodiment of the present invention.
[0025] 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
[0026] 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.
[0027] The various embodiments of the present invention provide a floating insert assembly for an injection moulding device to eject the moulded components with internal undercut. According to one embodiment of the present invention, the floating insert assembly has a floating insert in which undercut is machined. The insert is coupled to a pull back pin through a dowel. The pullback pin is extended beyond the ejection plates. Another dowel is provided at the bottom end of the pin. The component with internal undercut is ejected safely using the floating insert mechanism. The features around the undercut are allowed to expand to eject the component with internal undercut. The floating insert is coupled to the ejection plate. The ejector plate on which ejection pins and floating insert are mounted is actuated to eject component out of the the mould. The floating insert is gripped by the internal undercut of the component. The floating pin moves with the component when the mould is opened and the ejector plate is activated by a machine rod which pushes the component outwardly along with the floating insert. After a certain length of stroke the floating pin is stopped from moving further depending upon the space provided to float, and by this time the external surface of under cut surface is out of the punch insert and can flex outside for relieving the under cut. Component is further ejected out forcefully to jump out from the undercut by flexing. The floating punch is brought back into its position by the pull back pin which is activated by return back movement of the ejector plates.


[0028] The external surface of undercut surface is relieved from the punch insert. The external surface flexes outside the punch insert to relieve the undercut. The moulded component is ejected from the injection moulding apparatus. The pullback pin coupled to the floating pin is actuated to retrace the movement by the reverse movement of the ejector plate.
[0029] According to one embodiment of the present invention a floating pin assembly is provided to relieve internal undercuts in injection moulds. The component with internal undercut is ejected safely by the floating insert mechanism. The features around the undercut are allowed to expand to eject the component with internal undercut. The floating insert is coupled to the ejection plate. The ejector plate on which the ejection pins and floating insert are mounted is actuated to eject the mould. The floating pin is gripped by the internal undercut. The floating insert moves along with the ejection pins while ejection. The length of stroke of floating insert is controlled and movement of floating pin is ceased after required stroke. The external surface of undercut surface is relieved from the punch insert. The external surface flexes outside the punch insert to relieve the undercut. The moulded component is ejected from the injection moulding apparatus by further movement of the ejector pins. The pullback pin coupled to the floating pin is actuated to retrace the movement by the reverse movement of the ejector plate.
[0030] FIG. 1 illustrates the sectional and enlarged view of the injection molding apparatus. The sectional view of injection moulding apparatus comprises of fixed half 20 secured to stationary platen of the moulding machine. The moving half 10 is secured to moving platen of the machine. Feed system injects melted plastic into cavity 14. One end


of a pull back pin 6 is fastened to the ejection plate 8 using a dowel arrangement 4. The other end of the pull back pin 6 is coupled to a floating insert arrangement 2. The enlarged view of the dowel arrangement 4 comprises of a pull back pin 6 attached to ejection plate 8 by a dowel 5. The dowel arrangement 4 is used to precisely align the floating insert 6 to the required position. The enlarged view of the floating insert arrangement 1 comprises of the floating insert 2 fixed to the pull back pin 6 by a dowel 3. The dowel is used to align the floating insert 2 to the internal undercut of the moulded component precisely.
[0031] FIG. 2 illustrates the moulded component according to an embodiment of the present invention. The moving half 10 and the fixed half 20 are closed to form an impression with the shape of the component 12 under machine tonnage. The impression cools and solidifies to form the required component 12. The moulded component 12 comprises of an internal undercut II. The undercut 11 is devoid of any remains of steel for ejection from the injection moulding apparatus. The undercut 11 in the line of draw is released to eject the moulding component. The ejection pins 7 attached to the ejection plate 8 eject component 12 from the moulding apparatus.
[0032] FIG. 3 illustrates the opening of the moulding apparatus according to an embodiment of the invention. The moving half 10 is moved away from the fixed half 20. The moving half 10 comprises of ejection components including ejection plate 8. Ejector pins 7 are attached to ejector plate 8. A pull back pin 6 is attached parallel to ejector pins 7 using dowel 5. A floating insert 2 is attached to the pull back pin 6 using a dowel 3. The fixed half 20 comprises of mould cavity 14. The moving half 10 and the fixed half 20 are


closed to form an impression with the shape of the component 12 in cavity 14 under machine tonnage.
[0033] FIG. 4 illustrates the movement of floating insert and ejector pins according to an embodiment of the present invention. The ejector plate 8 is moved away from moving platen by machine rod. The ejector pins 7 protrude out and engaged to component 12 when the moving half 10 moves away from fixed half 20. The pull back pin 6 together with floating insert 2 moves with ejector plate 8. Floating insert 2 is engaged to internal undercut 11 of component 12.
[0034] FIG. 5 illustrates the disengagement of internal undercut from floating pin according to an embodiment of the present 'invention. The moving plate 8 is moved away from moving platen by machine rod. The ejection pins 7 engaged to moulded component 12 protrudes further from moving half 10. The movement of floating insert 2 is ceased. The external surface undercut 11 is relieved from punch insert. The external surface of undercut 11 flexes outside to relieve the undercut. The component 12 is ejected further from moving half 10.
[0035] FIG. 6 illustrates the ejection of moulded component according to an embodiment of the present invention. The moulded component 12 is ejected by ejection pins 7.
[0036] The ejection plate 8 moves towards the moving platen. The movement of ejection plate 8 activates the pull back pin 6 to pull the floating insert 2 to original position as shown in FIG. 3.


G) ADVANTAGES OF THE INVENTION
[0037] Thus the various embodiments of the present invention provide a system and method to eject a moulded component with internal undercut. The features around the undercut expand to eject the moulded component safely by forced ejection without distortion of features. The ejection components are simple and compact. The components to relieve the internal undercut are aligned precisely with simple actuation motion. The ejection mechanism is cost effective and efficient. The arrangement of the components is easy to dismantle and maintain.
[0038] 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.

[0039] 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 floating insert assembly for molding device including ejector plates for
releasing moulded components with undercuts, the assembly comprising:
a floating insert; and
a pullback pin coupled to floating insert through dowel;
wherein the floating insert is gripped by the internal undercut of the component
and is moved along with the component during the opening of the mould till the
component is ejected out of the mould.
2. The assembly according to claim I, wherein the floating insert is pulled back and restored to its position, after the component is ejected out of the mould.
3. The assembly according to claim I, wherein the retract movement of the floating insert is controlled by the pull back pin.
4. The assembly according to claim 1, wherein the pull back pin is extended beyond the ejector plate in the mould.
5. The assembly according to claim 1, wherein the pull back pin is provided with another dowel at the end which is extended beyond the ejector plate.
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