Title of Invention

A BUILT-IN FIXED SIDE EJECTION MECHANISM

Abstract

WE CLAIM: - 1. A Built in fixed side ejection mechanism for moulds and dies comprising a fixed assembly and a moving assembly, the said fixed assembly consists of a ejector plate and a holder plate characterize in that there is provided a collapsible collet fitted to the said holder plate a cylindrical bush fitted on the moving side capable of arresting the said collapsible collet to start the ejection of the component and the cylindrical pin provided on the fixed side preventing the said collet to collapse in the ejection.

Full Text

FORM 2 THE PATENTS ACT, 1970 (39 of 1970) COMPLETE SPECIFICATION (Section 10) 'A BUILT-IN FIXED SIDE EJECTION MECHANISM FOR MOULDS AND DIES' LARSEN & TOUBRO LIMITED L&T House, Ballard Estate, MUMBAI-400 001. Maharashtra State, India An Indian Company registered under the Provisions of the Companies Act, 1956 The following specification describes the nature of this invention and the manner in which it is to be performed. ORIGINAL 786/MUM/2002 GRANTED This invention is about a Novel built in positive ejection mechanism, for use in moulds and diecasting dies. This invention will be beneficial in simplifying design & manufacturing of moulds and diecasting dies. Moulds are used for producing plastic components and diecasting dies for producing aluminum / zinc / magnesium alloy castings of consistent quality and in large quantities, using moulding / diecasting machines. There are many types of moulds & dies and also moulding & diecasting machines in use. There are also many manufacturers of moulds, dies, moulding machines and die casting machines. There are also many manufacturers of standard mould parts and mechanism for moulds and die casting dies. DME, HASCO, STRACK, CUMSA etc are the leading standard element manufacturers for moulds and die casting dies. As a standard practice components are ejected from the moving side / core side / Punch side using ejection mechanism provided by the _ machine manufacturers. There is a need to provide built in ejector system for moulds and die casting dies when components are required to be ejected from fixed side / Cavity side / die side, since there is no provision of ejection on the machine from fixed side. Commonly used built in mechanical ejection systems from fixed side / Cavity side / die side requires precise control of machine opening stroke to prevent damage to the moulds or dies. However using hydraulic cylinders or air ejection for ejecting components from fixed side can avoid need for precise control on machine opening stroke. Use of hydraulic cylinders increases overall cycle time, mould cost and need for safety interlock for moulds and dies. Its use also makes moulds to be machine specific or requires dedicated hydraulic system for operating hydraulic cylinders. Air ejection also requires elaborate arrangements in moulds and dies. Moreover air ejection is not suitable for all components. There are several prevailing arrangements for ejection from fixed side / cavity side / die side. They are, 1) Length bolts for actuation of ejectors 2) Chain actuation 3) Slotted plate actuation 4) Hydraulic cylinder actuation 5) Air ejection and these are explained with the help of figures 1 to 4 of the accompanying drawings: 1) Length bolt actuation: This is one of the simplest and most commonly used mechanisms for ejecting the component from fixed side / cavity side / die side. Figure 1 shows assembly of a mould with length bolt actuation. In this method a length bolt (5) is fitted between moving side housing (1) and holder plate (3). Mould opens to a predetermined opening at parting line, to facilitate removal of component and further mould opening actuates ejector plate (4) through length bolt (5) and ejects the component from the cavity / die. There is a need to precisely control machine opening to prevent damage to the mould / die (See fig. 1). 2) Chain actuation: A simple and most commonly used mechanism for ejecting the components from fixed side / cavity side / die side. Figure 2 shows assembly of a mould with chain actuation. In this method a chain (6) is fitted between moving side housing (1) and ejector holder plate (3), Using fixing screws (5). Mould opens at parting line till sagging chain is stretched. Further mould opening pulls ejector plate (4) and ejects the component from the mould / die (See fig.2). There is a need for precise control on machine opening stroke to prevent damage to mould / die. Length of the chain also needs careful selection to have required gap between moving housing (1) and fixed housing (2). 3) Slotted plate actuation: This is also a simplest and commonly used mechanism for ejecting the component from fixed side / cavity side / die side. Figure 3 shows assembly of a mould with slotted plate actuation. In this method a plate with predetermined length of slot (6) is fitted between moving side housing (1) and ejector plate (4). Mould opens to a predetermined opening at parting me to facilitate remova) of component and further mould opening actuates ejector plate (4) and ejects the component from the mould / die. The fixed housing is indicated by numeral (2) and ejector holder plate housing by numeral (3) (See fig.3). 4) Hydraulic Cylinder actuation: This is also a commonly used method of ejecting the components from fixed stcje / cavity side / die side. Figure 4 shows assembly of a mould with hydraulic cylinder actuation. In this method either 2 hydraulic cylinders or 4 hydraulic cylinders are used according to the mould size. Hydraulic cylinders (5) with required stroke length are mounted on fixed side / cavity side / die side housing (2) and connected to holder plate f3) with the help of a coupler (6). When mould opens after preset time at parting line, hydraulic cylinder is actuated; which rn turn moves the holder plate (3) to eject the component. (See fig.4). This method is a cumbersome, machine dependent, expensive and requires regular maintenance. There is also a need for positive interlocking arrangement to prevent damage of the moulds / dies. The object of the present invention is, therefore to provide a novel mechanical ejection system for use in moulds and dies. This novel ejector mechanism from fixed side is simple and there is no need for precise control of machine opening stroke. According to this invention, therefore, a built in fixed side ejection mechanism for moulds and dies comprises a fixed assembly and a moving assembly, the said fixed assembly consists of a ejector plate and a holder plate characterized in that there is provided a collapsible collet fitted to the said holder plate a cylindrical bush fitted on the moving side capable of arresting the said collapsible collet to start the ejection of the component and the cylindrical pin provided on the fixed side preventing the said collet to collapse in the ejection. The invention will now be described with the help of suitable drawings accompanying this specification wherein the salient features have been shown by suitable numerals and referred to appropriately in the following description:- The drawing consists of 8 figures. Drawings are schematic only. Drawings are not to scale. Figure 5 shows the assembly of ejector mechanism as per this invention. Figure 6 shows the cylindrical pin. Figure 7 shows collet. Figure 8 shows cylindrical bush. Fig.5 shows assembly of cylindrical pin (1), collapsible collet (2) and a cylindrical bush (3). By varying the length of cylindrical pin (1), collet (2) and cylindrical bush (3) it is possible to achieve desired ejection strokes. The cylindrical pin (1) prevents collet (2) to collapse till required ejection stroke is achieved. Once the required ejection stroke is achieved the predefined length of cylindrical pin allows collet to collapse and permit further movement of moving housing without any restriction. Fig. (9) shows mould assembly with both halves in closed position and ready for producing component by injecting material. It shows cylindrical pin (1), collapsible collet (2) and a cylindrical bush (3) haying a definite geometry. The cylindrical pin (1), guarantees the location. There is a holder plate (4), an ejector plate (8) and a set of return pins (7). The collet (2) is held in holder plate (4), the pin (1) is located in the base plate (comp plate) (5) and the bush is fitted into the moving housing (6). All the parts denoted by the above numerals in fig.9 also denote the same parts in the subsequent figures referred to below. After pre¬set time is over the mould opens at parting line 'PL' to the required gap as shown in fig. 10. This is achieved through predefined length of collet (2) and length of counter bore of cylindrical bush (3). After tapered surface of bush touches the tapered surface of collet and cylindrical pin is inside the tapered portion of collet, so it cannot collapse hence further opening of mould makes ejector plate assembly to move in mould opening direction (see fig. 11). Fig. 12 shows after required ejection stroke is completed, the collet (2) will clear off from cylindrical pin (1), thereby allowing collet (2) to collapse and come out of cylindrical bush (3). This allows unrestricted opening of mould moving half and there is no need to precisely control mould opening stroke. During closing of mould moving half moves towards fixed half and the tapered surface of cylindrical bush (3) comes in contact with tapered surface of collet (2). This makes collet (2) to collapse (as at this time cylindrical pin is below the tapered portion collet) and enter the cylindrical bush (3). As mould closes further the return pins (7) comes in contact with moving half, pushing the ejector plates consisting of holder plate (4) & ejector plate (8) to its original position and at the same time the cylindrical pin makes collet to expand. The stages of the closing of the moulds are shown in the accompanying figures nos.13,14 & 15. In view of the unique and simple construction of the system according to the invention, it is easy to assemble and disassemble various parts in the mould. The above invention thus saves time and prevents possible damage to the moulds and dies and avoids precise machine settings, reduces costs of ejection and proceeds to free maintenance. WE CLAIM: - 1. A Built in fixed side ejection mechanism for moulds and dies comprising a fixed assembly and a moving assembly, the said fixed assembly consists of a ejector plate and a holder plate characterize in that there is provided a collapsible collet fitted to the said holder plate a cylindrical bush fitted on the moving side capable of arresting the said collapsible collet to start the ejection of the component and the cylindrical pin provided on the fixed side preventing the said collet to collapse in the ejection. 2. A Built in fixed side ejection mechanism for moulds and dies as claimed in claim 1 and substantially describes herein with reference to figures 5 to 15 of the drawings. Dated this 2nd day of September, 2002

Documents:

786-mum-2002-cancelled pages(29-11-2004).pdf

786-mum-2002-claims(granted)-(29-11-2004).doc

786-mum-2002-claims(granted)-(29-11-2004).pdf

786-mum-2002-correspondence(29-11-2004).pdf

786-mum-2002-correspondence(ipo)-(27-11-2003).pdf

786-mum-2002-drawing(29-11-2004).pdf

786-mum-2002-form 1(02-09-2002).pdf

786-mum-2002-form 19(01-09-2003).pdf

786-mum-2002-form 2(granted)-(29-11-2004).doc

786-mum-2002-form 2(granted)-(29-11-2004).pdf

786-mum-2002-form 3(20-01-2000).pdf

786-mum-2002-form 5(01-09-2003).pdf

786-mum-2002-power of authority(02-09-2002).pdf

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