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:
MODULAR INSERT RETAINER ASSEMBLY FOR
MOULDS
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 more particularly it relates to provide an insert retainer assembly to hold inserts on molds in inaccessible areas during industrial production.
B) BACKGROUND OF THE INVENTION
[0002] Thermoplastic molded articles are used extensively in everyday life. Thermoplastics are linear or branched polymeric materials which melt when heated and solidify when cooled. 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] Molding is a process of manufacturing by shaping pliable raw material or plastic using a rigid frame or model called a mold. The plastic raw material is heated until it melts and then forcing this melted plastic under pressure with the help of injection molding machines into a mould where it solidifies. After this, the mould is opened and the product is ejected out. The plastic molds can be obtained by using various molding processes such as compression moulds, injection moulds, transfer moulds etc. Any of these molding processes can be selected based on the type of material to be molded.


[0004] A typical mold consists of fix half and moving half. They are either mounted horizontally or vertically on the molding machines based on the machine construction. The components after molding are ejected by means of ejector pins that are given on the half portion, where the component adheres after solidification.
[ 0005] Some thermo set material components may require threads for fastening in the assembly. Since the thermo set material is brittle in nature and having less strength, it is not feasible to provide any thread formation directly on component. Normally it achieved by putting metal threaded inserts on required positions while molding. For achieving this, it is necessary to close the threaded portion of the insert to restrict molten plastic material entry. Being having very less viscosity of material in molten condition for thermo set plastics, the sealing is more difficult to achieve. Hence the threaded insert to be molded is screwed on an insert carrier pin which has matching threads and the assembly of this is loaded on the mould. This ensures better sealing and restriction for material running into threaded area. This insert carrier pin also comes out along with the component from mould. It is then unscrewed from the component leaving the required threaded insert only on the component,
[0006] There are many plastic components which require metallic inserts to be molded with the component during molding. Inserts are typically metallic parts made from hexagonal bar to prevent rotational movement and may be grooved in one or more places to prevent axial movement. These inserts are used in all kinds of plastic components


where the threaded screws are commonly used for fixing other components to molding with nut, Molding inserts lead to increase in cycle time of the mould during production.
[0007] Various methods are available in the prior art for mounting inserts on the mould. The conventional methods available uses direct method where in the insert is directly mounted on the mould, mounting using insert carrier, mounting using insert carrier and ball catch arrangement. The convention available methods are suitable only for mounting of inserts on bottom half of the mould. It requires precise machining of inserts. There arises a case wherein the insert may jump from its position and can damage the mold while production. Hven though the inserts can be mounted on the top half of the mold using ball catch arrangement, an adequate place is required on the tool to provide this arrangement. It may lead to the insert carrier being long and hence more prone to breakage.
[0008] There are cases where the inserts are to be molded on the top half of the mold and in the areas which are difficult in access to the operator of the molding machine who runs the production. This causes inconvience to the operator and hence increases the molding time to produce a component and hence increasing the part cost. In some case, the component geometry or the tool construction is such that there is no place for using ball catch to hold the insert carriers.
[0009] Hence there is a need to provide a modular insert retainer assembly to hold insert on top half of the molds in inaccessible areas during production.
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C) OBJECTS OF THE INVENTION
[00101 The primary object of the present invention is to provide an insert retainer assembly to hold insert on molds in inaccessible areas during production.
[0011] Another object of the present invention is to provide an insert retainer assembly with a sheet metal spring in the insert carrier to hold the inserts by means of the flexible action of the spring,
[0012] Yet another object of the present invention is to provide an insert retainer assembly which is compact, easily replaceable and loading and unloading of the insert is made simple to increase the production time.
[0013] Yet another object of the present invention is to provide an insert retainer assembly which can be easily standardized for different types of insert carriers.
[0014] 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
[0015] The above mentioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and studying the following specification.


[0016] The various embodiments of the present invention provide a modular insert retainer assembly to insert and hold inserts on molds in inaccessible areas during production. It includes a sheet metal spring, which is given a shape to hold itself around a holder. The insert is attached to the insert carrier by a tapped stud. The tapped stud is inserted into the relieve provided on the Holder. The insert and the insert carrier assembly arc held in the insert holder by the flexing action of the sheet metal spring.
[0017] According to one embodiment of the present invention, the sheet metal spring is used to hold insert itself around an ejector pin or stationery pin at the same time facilitate holding of inserts by means of its tlexing action. It is suitable for holding inserts on top half of the moulds. The insert retainer assembly in the present invention is very compact, easily replaceable and loading and unloading of the insert is made simple to increase the production time. The assembly design can be easily standardized for different types of insert carriers.
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:
[00I9| FIG. 1 shows a cross sectional view of the insert retainer assembly according to one embodiment of the present invention.


[0020] FIG. 2 shows a cross sectional view of the molding machine indicating the position of the ejector plate during loading and after loading of the insert retainer assembly.
[0021] Although specific features of the present invention arc 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
[0022] 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.
[0023] The various embodiments of the present invention provide a modular insert retainer assembly to insert and hold inserts on molds in inaccessible areas during production. It comprises of a sheet metal spring which is compact in size and designed to insert and hold inserts on molds in inaccessible areas during production. This spring is designed to hold itself around an ejector pin or any stationary member of the mould at the
3 1 MAR 2009

same time facilitate holding of inserts by means of its flexing action. It provide a compact design which makes the loading of insert simple, hence saving considerable time in producing components.
[0024] FIG. 1 shows a cross sectional view of the insert retainer assembly 100 according to one embodiment of the present invention. With respect to figure 1, the insert 106 and the insert carrier 101 assembly is held in the insert holder 104 by flexible action of the spring 103, The spring is given a shape 102 to hold itself around the holder 104. Initially the insert 106 is attached to taped stud 105 inside the insert carrier 101. The taped stud is then inserted into the relieve provide on the holder 104. The insert retainer assembly 100 can be fixed to the ejector on the mold. Because of the spring action, the insert can be easily fixed to the insert carrier during molding,
[0025] FIG. 2 shows a cross sectional view of the molding machine indicating the position of the ejector plate during loading and after loading of the insert retainer assembly. It shows fixed half 201 and a moving half 202 of the molding machine. The mold is mounted vertically on the molding machines. An ejector is provided on the mold to eject the components after molding. In order to obtain the required metallic inserts on the plastic components, the insert retainer assembly 100 is fixed to the ejector plate as shown in figure. The modular insert retainer 100 in the present is so designed that it is very easy to fix on the top half 202 of the mould. Initially the operator has to load the insert retainer assembly 100 on to the ejector before starting the molding process. The ejector plate is in down position during loading of the insert retainer 100 as shown in
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figure 2a. Once the insert retainer assembly 100 is loaded the ejector plate is pulled up as shown in figure 2b. As a result, when the molding process starts the insert exactly fits with the plastic molded. The sheet metal spring is used to hold insert itself around an ejector pin or stationery pin. It facilitate holding of inserts by means of its flexing action of the spring, hence loading of insert is very easy, ft is suitable for holding inserts on top half of the moulds. The insert retainer assembly in the present invention is very compact, easily replaceable and loading and unloading of the insert is made simple to increase the production time. The assemhly design can be easily standardized for different types of insert carriers.
G) ADVANTAGES OF THE INVENTION
[0026] The various embodiments of the present invention provide a modular insert retainer assembly to insert and hold inserts on molds in inaccessible areas during production. It is suitable for holding inserts on top half of the moulds. The insert retainer assembly in the present invention is very compact, easily replaceable and loading and unloading of the insert is made simple to increase the production time. The assembly design can be easily standardized for different types of insert carriers.
[0027] 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.


CLAIMS
What is claimed is:
1. A modular insert retainer assembly for moulds comprising:
a retainer housing;
a holder provided in the retainer housing;
an insert carrier inserted into the holder;
an insert attached to the insert carrier; and
a spring provided in the retainer housing;
wherein the spring holds the holder in the insert carrier by the flexing action.

2. The assembly according to claim 1, wherein the spring is a sheet metal spring,
3. The assembly according to claim 1, wherein the spring is designed with a shape to hold itself around the holder in the retainer housing.
4. The assembly according to claim 1, wherein the holder has a relieve.
5. The assembly according to claim 1, wherein the insert carrier is inserted into the relieve of the holder.
6. The assembly according to claim 1, wherein the insert is attached to the insert carrier through a tapped stud.
Date: March 30, 2009. RAKESH PRABHU
Place: Bangalore. Patent Agent