FORM 2
THE PATENTS ACT, 1970 (39 of 1970)
As amended by the Patents (Amendment) Act, 2005
&
THE PATENTS RULES, 2003 As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION
(See section 10 and rule 13)
I TITLE OF THE INVENTION
A drill jig for drilling holes on two planar surfaces of an end shield of an alternator
2. APPLICANTS
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai - 400 030, Maharashtra, India, an Indian Company
3. INVENTOR
Bhujbal Eknath, Crompton Greaves Ltd, LT Motors Division (M3), A-6/2 MIDC, Ahmednagar 414001, Maharashtra, India, an Indian national
4. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention and the manner in which it is to be performed.

BACKGROUND OF THE INVENTION
Drilling operation on machinery is generally performed by fixed drilling machine in industrial establishments. The drilling machine has drilling spindles fixed thereto for directing of the drill to a location requiring drilling,
In manufacturing of alternators (motors, generators etc.) the process of drilling inter alia is required during manufacturing of end shield of the alternator. The end shield is generally required to be fixed with other part of the alternator using nuts/ bolts, screws etc to pass through holes on the end shield. For the drilling of holes on the end shield the drilling operation is performed on the drilling machine.
Generally in available systems of drilling holes in the end shield a traditional drill jig is provided which locates and guides a drilling machine user to the correct location in the end shield where the holes are required to be drilled. However, the traditional drill jigs only allow drilling operation on a surface facing the drill. For making holes on another surface the traditional drill jig along with the end shield fixed therein is required to be flipped to enable the other surface to face the drill.
This usually requires a considerable manual effort by the user himself or with help of other machinery for flipping of the traditional drill jig. Also the time for performing the drilling operation increases owing to time spent on flipping as well as locating of the end shield. Also the alignment may be hampered during the flipping operation causing overall reduction in processed job in limited time.

There is therefore needed a system which enables quicker, safer and easy drilling operation on the end shield of an alternator.
SUMMARY
A drill jig for drilling holes on two planar surfaces of an end shield of an alternator is described. In one embodiment of the present invention a drill jig for drilling holes on two planar surfaces of an end shield of an alternator comprises of a square shaped jig plate having plurality of jig bushes, to rest on a first planar surface of the end shield. Further a ring shaped jig plate having plurality of jig bushes, to rest on a second planar surface of the end shield is provided. Two support blocks located diametrically opposite and being detachably attached on the ring shaped jig plate on one side and on the square shaped jig plate on the other side thereby allowing drilling of holes in the end shield at the first planar surface and the second planar surface from one direction are also provided.
The drill jig as provided enables drilling of holes on the two planar surface of the end shield from one direction without requiring flipping of the end shield and/or the jig plate. The accuracy and ease of operation for drilling holes on the end shield is improved. Also the operation of drilling using the said drill jig is safer.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference will be made to embodiments of the invention, examples of which may be illustrated in the accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in the context of these

embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments
Fig. 1 shows an exploded view of the drill jig assembly as per one embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A drill jig for drilling holes on two planar surfaces of an end shield of an alternator is described. In one embodiment of the present invention the drill jig comprises of two jig plates to cater to two planar surfaces of an end shield that require drilling.
In one embodiment a square shaped jig plate having plurality of jig bushes is provided, this square shaped jig plate during drilling rests on the first planar surface. A ring shaped jig plate is provided to rest on the second planar surface to allow drilling of holes through that planar surface.
In the following description, for purpose of explanation, specific details are set forth in order to provide an understanding of the invention. It will be apparent, however, to one skilled in the art that the invention may be practiced without these details. One skilled in the art will recognize that embodiments of the present invention, some of which are described below, may be incorporated into various drill jigs for easier drilling. It is understood that one skilled in art may modify or change the data used in the examples "described in the specification.

Reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment.
As per one embodiment of the present invention a drill jig for drilling holes on two planar surfaces of an end shield of an alternator is shown with reference to figure 1. The drill jig comprises of a square shaped jig plate 203 having plurality of jig bushes 203a-203d. The square shaped jig plate during operation of drilling rests on a first planar surface of the end shield (10).
Further a ring shaped jig plate 205 having plurality of jig bushes 205a-205I is provided to rest on a second planar surface of the end shield during the operation of drilling. The drilling on the end shield at two planar surface thereof happens at points below each of the jig bush of the square shaped jig plate and the ring shaped jig plate. More particularly the square shaped jig plate caters to the first planar surface (10a) while the ring shaped jig plate caters to the second planar surface (10b) of the end shield.
Two support blocks 207a and 207b are located diametrically opposite and are detachably attached on the ring shaped jig plate on one side and on the square shaped jig plate on the other side. The support blocks therefore hold the two jig plates at proper distance from each other while providing mechanical stability to the drill jig.

The support blocks may be designed keeping in view the distance between the two planar surfaces desired.
In one embodiment of the present invention a resting plate is located below the end shield on which the drill holes are required to be drilled. The resting plate may be provided to have holes coinciding with the jig bushes on square shaped jig plate allowing easy passing of drill during drilling operation of the end shield rested on said resting plate. The drill easily passes through the jig bushes on the square shaped jig plate and does drilling on the required locations on the first planar surface of the end shield. However, as the drill would during operation pass further down. The presence of holes in the resting plate minimizes the chances of the drill harming the base over which the drilling operation is carried out. A person skilled in the art may realize that the resting plate may be provided to be part of the drill jig.
The resting plate may be provided with a clamping pole located at the centre thereof to pass through a guiding hole 205k provided in the centre of the square shaped jig plate for proper alignment of the resting plate and the square shaped jig plate.
In another embodiment at least one locating pole (209h) on said resting plate passable through atleast one locating hole (203d) on the square shaped jig plate allowing alignment of jig bushes of the square shaped jig plate with the holes of the resting plate is provided. This also restricts circular movement of the jig plate during drilling operation.

A nut 211a and a c-washer 211b may be provided to fix on the clamping pole to restrict upward movement of the square shaped jig plate with respect to the resting plate.
The drill jig as provided enables drilling of holes on the two planar surface of the end shield from one direction without requiring flipping of the end shield and/or the jig plate. The accuracy and ease of operation for drilling holes on the end shield is improved. Also the operation of drilling using the said drill jig is safer.
The foregoing description of the invention has been described for purposes of clarity and understanding. Although embodiments of the present invention have been described relative to a few standards, and associated attributes therein, one skilled in the art will recognize that the present invention is also very much applicable to other such methods and systems. It is not intended to limit the invention to the precise form disclosed. Various modifications may be possible within the scope and equivalence of the appended claims.

We Claim:
1. A drill jig for drilling holes on two planar surfaces of an end shield of an
alternator comprising:
a square shaped jig plate having plurality of jig bushes, to rest on a first planar surface
of the end shield;
a ring shaped jig plate having plurality of jig bushes, to rest on a second planar
surface of the end shield;
two support blocks located diametrically opposite and being detachably attached on
the ring shaped jig plate on one side and on the square shaped jig plate on the other
side thereby allowing drilling of holes in the end shield at the first planar surface and
the second planar surface from one direction.
2. The drill jig for drilling holes on two planar surfaces of an end shield of an alternator as in claim 1, wherein the jig bushes on the square shaped jig plate are located at each of the corners of the square shaped jig plate.
3. The drill jig for drilling holes on two planar surfaces of an end shield of an alternator as in claim 1, wherein the jig bushes on the ring shaped jig plate are located along the planar surface of the ring shaped jig plate.
4. The drill jig for drilling holes on two planar surfaces of an end shield of an alternator as in claim 1, further comprising a resting plate having holes coinciding

with the jig bushes on square shaped jig plate allowing easy passing of drill during drilling operation of the end shield rested on said resting plate.
5. The drill jig for drilling holes on two planar surfaces of an end shield of an alternator as in claim 4, wherein the resting plate comprises of a clamping pole placed thereon and a guiding hole in the centre of the square shaped jig plate allowing passing of the clamping pole through said guiding hole thereby allowing proper alignment of the resting plate and the square shaped jig plate.
6. The drill jig for drilling holes on two planar surfaces of an end shield of an alternator as in claim 4, further comprising at least one locating pole on said resting plate passable through atleast one locating hole on the square shaped jig plate allowing alignment of jig bushes of the square shaped jig plate with the holes of the resting plate.