FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
Title of the invention. - AN IMPROVED PUNCH AND DIE ASSEMBLY FOR BENDING
SMALL COMPONENTS
2. Applicant
(a) NAME : LARSEN & TOUBRO LIMITED
(b) NATIONALITY : An Indian Company
(c) ADDRESS : L&T House, Ballard Estate. Mumbai 400 001
State of Maharashtra. India
3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed :

Field of the Invention
The present invention relates to the field of Bending Die, which are used to bend metal components to the desired angle. This invention more particularly relates to an improved punch and die assembly comprising a unique location mechanism for use in the bending dies where small components are bent during a bending operation to provide high precision bending without introducing any structural damage to punch.
Background and Prior Art
Generally, a component is bent in a bending die as shown in fig. 1. The component is placed on the die with the component partly on the Ejector block (3) and the Die block (4), bending takes place when the Punch (2) moves down along with the Top Plate (1) and bends the component on it's way down till Ejector block (3) hits the Base plate (6) . If the component is not located , which means that on it's way down the component is free to move as shown in Fig.1B and 1C. This results in the component being bent in an undesired fashion. Hence it becomes necessary to lock the motion of the component in these two directions while bending operation is performed, this is achieved by proper location of the component.
There are various conventional methods for locating the component as follows
1 . Locating pin
2 . Nest Plate
3. Combination of the above
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1) Locating Pin:
In this method the component's motion as shown in fig.2 is locked by means of inserting two pins in to the holes (A) available in the component. Thus the component is properly located at the time of bending. The locating pins are stationary and project out of the surface of Ejector block to an amount approximately 3mm more than the thickness of the component. The bending punch has a relief hole to allow the pin to enter in to it while the bending takes place. This method can only be adopted if the component has two holes for location. This is the most widely preferred method of location as the component is accurately located.
2) Nest Plate:
In this method the component's motion is locked by means of placing it in between four plates as shown in fig.3. The plates can be separate elements or can be an integral part of the Ejector block. The plates are made such that the component fits in properly any there is very less space for any movement. This method is only adopted in cases where there is no hole in the component, which could be used to locate by means of locating pins. The thickness of nest plates is lesser than the thickness of the component. The component location is not as accurate as that provided by locating it by pins.
3) Combination of the above:
As shown in figure 4 this method is the combination of the above two methods, in which the location is done by means of using two locating/nest plates instead of four as in case of nest plate
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method and one pin instead of two as in case of the locating pin method. This method is adopted only in cases where there is only one hole available for location. The pin constraints the motion of the component in one direction and the two plates in the other.
As discussed in the above three methods the two best choices for location are 1) Locating Pin 2) Combination of nest plate and Pin. When location is done by means of a pin it becomes necessary that the Bending punch (2) has a relief hole for the pin to enter into it while the bending takes place (Ref. Fig.5).
But if the hole available is very close to the bend line and the accuracy required is quite high which possibly cannot be achieved by means of the nest plate location. When the hole is too close to the bend line it is not possible to provide locating pin as this would require a relief hole in the bending punch, but providing a relief hole would weaken the punch and may even cause breaking of the punch.
US5,099,675 describes an improved punch and die assembly for bending deformable work pieces with high dimensional precision and without introducing structural damage to the finished piece parts. However, no flexible location mechanism arrangement is found in this prior art.
Some times component is so small and design is such that, it becomes difficult to properly locate the component in the Bending Die before the bending operation can actually take place.
Thus there is a need to provide for a location mechanism to accurately locate the component in the Bending Die before and during the bending operation.
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Objects of the Invention

It is one of the objects of the present invention to overcome the disadvantages / problems prevailing in the prior art.
Another object of the present invention is to provide a novel punch and die assembly comprising a location mechanism for bending dies.
Another object is to provide high precision bending of components.
Another object of the present invention is to prevent damaging of the punch.
Summary of the invention
of the present invention there is provided die assembly for bending components, said
According to one aspect an improved punch and assembly comprising :
top plate;
punch block means mounted to said top plate, said punch means being movable along with the top plate;
ejector block means operatively located in alignment with the top plate, said ejector block means acting as a surface for partially resting the component to be bent,
wherein said ejector block means securing flexible movably located location mechanism, predetermined portion of which protruding out of the ejector block means to an appropriate height so as to locate
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and hold the component in an accurate and desirable position during bending operation.
Detailed Description of the invention
In the present invention punch and die assembly comprises top plate on which the punch block means is mounted and is movable along with the top plate. The ejector block means is operatively located in alignment with the top plate and the surface of the ejector block acts as a resting surface for the components to be bent. The ejector block means secures flexible movably located location mechanism predetermined portion of which protrudes out of the ejector block means to an appropriate height so as to locate and hold the component in an accurate and desirable position during bending operation. The location mechanism is placed in the ejector block of the bending die. The location mechanism comprises locating pin, spring, screw means. The ejector block acts as a housing for the mechanism. The length of the Locating pin is kept such that it projects out of the component by 4mm. However, length of projection of the pin as described hereinabove does not restrict the scope of the present invention. Any length of projection based on the amount of safe deflection that the spring permits will serve the purpose.
The spring is designed to compress before the ejector block starts moving down, so that the component is properly held between the punch and the ejector block. The grub screw is used to hold the mechanism in place as well as the maintain the pre-compressed load on the Locating pin.
The ejector block is also spring loaded but the compression load for this spring is much higher than that of spring. The screw means is provided just to maintain the pre-compression load of the spring. The spring is preferably a grub screw. However, this is not
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a restriction to the present invention and even a different type of screw can be used for this purpose depending on the space available to place it below the spring.
Brief description of the accompanying drawings
Figure 1 illustrates a conventional bending die.
Figure 2 illustrates locking of the component motion in a conventional bending die.
Figure 3 illustrates locking of component's motion by means of plates.
Figure 4 illustrates two locating pins and nest plates in combination.
Figure 5 illustrates a punch with relief holes for the pins.
Figure 6 illustrates the punch and bending die assembly of the present invention.
Figures 7a, 7b and 7c illustrate different stages of bending operation in the assembly of the present invention.
Detailed description of the accompanying drawings
The invention will now be illustrated with reference to accompanying drawings, which are provided for ready and better understanding of the invention. The drawings represent only a specific working embodiment of the assembly according to the
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invention although variants of the assembly may be made within the scope and ambit of the present invention.
In figure 6, the locating mechanism is placed in the ejector block (3) of the Bending Die. Elements of mechanism are Locating Pin (8), Spring (9), Grub Screw (10). The Ejector Block (3) acts as a housing for the mechanism.
Spring (9) is designed to compress before the ejector block (3) starts moving down, so that the component (7) is properly held between the Punch (2) and the ejector block (3).
Working of the invention
Fig. No.7 (Stage-1):
Die is open and Top plate & Punch are at the top position, the ejector block is at the same level as that of Die block. The locating pin projects out to it's maximum and the component is located with reference to the locating pin.
Fig. No.7 (Stage-2):
moved down and have touched the pin to move down compressing the
The top plate and punch has component causing the locating spring.
Fig. No.7 (Stage-3):
The further downward movement of the punch causes the bending of the component, during which the component is guided and located accurately throughout the bending operation.
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The invention has been shown and described in a preferred form only and many variations may be made in the invention, which will still be comprised within its spirit. It is understood, therefore, that the invention is not limited to the details cited above. The spring and screw means as herein described do not limit the scope of the present invention. The same can be replaced by its technical equivalence and yet the invention can be performed. The structure thus conceived is susceptible of numerous modifications and variations, all the details may furthermore be replaced with elements having technical equivalence. In practice the materials and dimensions may be any according to the requirements, which will still be comprised within its true spirit.
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We claim
1. An improved punch and die assembly for bending components,
said assembly comprising:
top plate;
punch block means mounted to said top plate, said punch means being movable along with the top plate;
ejector block means operatively located in alignment with the top plate, said ejector block means acting as a surface for partially resting the component to be bent,
wherein said ejector block means securing flexible movably located location mechanism, predetermined portion of which protruding out of the ejector block means to an appropriate height so as to locate and hold the component in an accurate and desirable position during bending operation.
2. Assembly as claimed in claim 1, wherein the location mechanism comprises location pin being mounted on a spring.
3. Assembly as claimed in claim 2, wherein the spring being designed so as to compress before the ejector block starts moving down so that the component is properly held between the punch and the ejector block.
4. Assembly as claimed in any of the preceding claims further comprising a screw means adapted to hold the location mechanism in place.
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Assembly as claimed in claim 4, wherein the screw means is further adapted to maintain pre-compressed load on the locating pins.
Assembly as claimed in claim 5 wherein the screw means is preferably a grub screw.
An improved punch and die assembly for bending components as substantially herein described and illustrated with reference to accompanying figures.

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ABSTRACT
TITLE : AN IMPROVED PUNCH AND DIE ASSEMBLY FOR BENDING SMALL COMPONENTS
The present invention relates to an improved punch and die assembly for bending components. The assembly comprises top plate (1), punch block means (2) mounted to said top plate (1), ejector block means (3) on which the component (7) is partially rested said ejector block (3) is operatively located in alignment with the top plate (1) . The ejector block means (3) secures flexible movably located location mechanism (8,9,10), predetermined portion of which protruding out of the ejector block means (3) to an appropriate height so as to locate and hold the component in an accurate and desirable position during bending operation.
Figure 6