FIELD OF INVENTION
The present invention relates to a drill jig fixture for drilling at a compound angle on a seal body of a turbogenerator and the method for the same. More particularly the invention relates to an adjustable sine table mountable drill jig fixture for drilling at a compound angle on a seal body of shaft seal assembly of a turbogenerator for sealing of hydrogen inside the stator.
BACKGROUND OF THE INVENTION
Work holders and drill fixtures have been employed heretofore to facilitate the drilling of a hole in a work piece at a compound angle, however, the several devices of the prior art have not proven entirely satisfactory in as much as they are complicated in design and construction, expensive to manufacture, and difficult to use.
In an exemplary mean, present invention is described for a turbogenerator seal body in which plurality of compound hole are required to be drilled. A generator driven by turbine which is used for conversion of mechanical energy to electrical energy. Stator frame, Rotor, End shield, Seal Body are the main components of Turbo generator. Seal Body is one of the most important part of Shaft Seal Assembly which retains Seal Ring in Turbo Generator for Sealing of Hydrogen inside the Stator.

If these holes are performed on a horizontal borer, in which through practices of prior art are applied i.e. providing angle to the spindle and a relative angle to the job, multiple job settings are required which not only poses a great threat to the job quality and consumes cost expensive resources but also makes the job largely dependent of operator's expertise in performing multiple job settings and doing the required job setting calculations.
Therefore, there exists a need for universally adjustable work holder and drill jig fixture, particularly for jobs like turbogenerator seal body, where the operation can be performed in a single setting and in easier way.
In the old process, after turning of seal body marking of angle holes is done. Then few holes at 12°, 72° and 42° are done in horizontal borer and rest of the holes at 24° and 36° are done in angular drilling machine. In this process, the holes that are drilled are not accurate and cycle time is very high because of the following:
1. Marking time.
2. Job setting time.
3. Breakage of drill.
Also these machines have high operating cost per hour.
Therefor there was a need for a universally adjustable working holding and drill jig fixture, particularly for jobs like turbogenerator seal body where the operation can be performed in a single setting and in much easier way.

OBJECTS OF THE INVENTION
Therefore, it is an object of the invention to propose a drill jig fixture for drilling at a compound angle on a seal body of a turbogenerator, which is capable of eliminating the disadvantages of prior Arts.
Another object of the invention is to propose a drill jig fixture for drilling at a compound angle on a seal body of a turbogenerator, which is capable of making the process much easier and simple and making the entire process highly economical.
A still another object of the invention is to propose a drill jig fixture for drilling at a compound angle on a seal body of a turbogenerator, which is capable of supporting the work piece at any desired compound angle relative to the drill jig.
SUMMARY OF THE INVENTION
A sine table mountable work holder and drill jig fixture for performing compound drilling is proposed in which the base plate (10) is clamped to the sine table using key slots (19) and tapped holes (16) to first provide the required angle to the base plate in one plane. The work piece is radially placed the on the base plate (10) while adjusting the overlapping positions of threaded aperture (15) on base plate and hole (21) on workpiece (20) so as to position the point and line of drilling in the work piece (20) relative to the drill for straight holes. Through various connections (15, 16, 19) base

plate is moved radially clockwise or counterclockwise to adjust the first angle as desired and then tightens the base plate (10) at this angular position with respect to the sine table through hole (16) and key slots (19). The sine table provides a second angle through on which the base plate (10) is mounted in order to perform the drilling operation relative to the drilling point and line of drilling relative to the work piece (20).
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 shows schematic diagram of the developed drill jig fixture, in accordance with present invention;
Figure 2 shows schematic diagram of turbogenerator seal body, in accordance with present invention.
Figure 3 shows sectional view of seal body having angular and straight holes, in accordance with present invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
Before describing in detail, universally adjustable work holder and drill jig fixture in accordance with the present invention, it should be observed that the present invention resides primarily in a novel and non-obvious combination of hardware elements and method steps. Accordingly, these elements and steps have been represented by conventional elements and steps in the drawings, showing only those specific details that are pertinent to the present invention so as not to obscure the

disclosure with details that will be readily apparent to those skilled in the art having the benefit of the description herein.
Referring now to the drawing wherein like numerals refer to like and corresponding parts throughout the several views, the work holding and drill jig fixture F disclosed therein to illustrate the invention comprises a sine table mountable universally adjustable stepped base plate (10) for adjusting the angulation of the work piece (20) to any desired angle, and a universally adjustable drill jig fixture F adapted to support the drill relative to the work piece (20) at any desired compound angle.
More particularly, the adjustable work holding portion comprises a stepped base plate (10) having plurality of circularly arranged tapped holes (16) on stepped section (13) towards the center of the base plate (10) which carry the threaded means therein to rigidly lock the base plate to the sine table (not shown). Plurality of key slots (19) are also provided towards the center of the base plate (10) to be keyed to the sine table and adjacent to the arrayed tapped holes (16) that receive key means to further restrict the rotary degree of freedom of the fixture (10) along with threaded means in tapped holes (16) and thus secure the base plate to the sine table.
By adjusting the threaded means in the threaded apertures (16) of the base plate (10) the angulation of the base plate (10) can be universally adjusted so as to position the work piece (20) at any desired angle relative to the drill.

The base plate (10) has an upstanding flange (11) machined along its circumferential edges to support the work piece and plurality of circularly arranged threaded apertures (15) at a diameter d on pitch circle diameter (18) of stepped section (12) which receive the clamping bolts which lie in the slots (21) of the work piece (20) securing same to the base plate (10). Upon loosening and detaching the bolts, the work piece (20) can be moved radially clockwise or counterclockwise to adjust the angle thereof as desired. For repeated requirements of a compound hole (30) or straight hole (31) in exemplary work piece (20) as shown in figure 3, these threaded apertures (21) can be angularly aligned beforehand so as to minimize or completely eliminate the requirement of measuring angles and repeated settings required thereof.
The stepped sections (12, 13) provide supporting steps or collars to the work piece, if required, and additionally help in lowering the weight of the fixture F.
In operation the user radially places the work piece (20) on the base plate (10) and adjusts the overlapping positions of threaded aperture (15) on base plate and hole (21) on workpiece (20) so as to position the point and line of drilling in the work piece (20) relative to the drill line as desired whereupon the user clamps with suitable means the base plate (10) to the bed or secure the same in any other desired manner and it has been found that the use of a sine table holds and positions the base plate, and the work piece thereof, satisfactorily.

The user then loosens the various connections (15, 16, 19) to first provide the required angle to the base plate in one plane through sine table and then tightens the base plate (10) while adjusting its angular position of with respect to the sine table through hole (16) and key slots (19). The user then positions and locates the drill relative to the drilling point and line of drilling relative to the work piece (20) and upon having same adjusted properly he tightens the threaded means.
By the development of the new fixture, following improvements are done:
1.) Reduction in Marking time
2.) Reduction in Cycle time
3.) Minimum possibility of Tool breakage
4.) Elimination of Transportation time
5.) Better quality achieved in drilled holes
6.) Establishment of process on cheaper m/c in terms of operational cost

Saving
Man Hours Cost Saving Per Set = 28200-4000 = INR 24200
Machining Cost Saving Per Set = 116760-7616 = INR 109144
Tooling Cost Saving Per Set = 13200-2200 = INR 11000
Electrical Units Saving Per Set = 2270-300 = 1970 kWh
Electrical Units Cost Saving Per Set = 1970x5 = INR 9850
Financial Cost Saving Per Set = 24200 + 109144 + 11000 + 9850 = INR 154194
As Per Shop Capacity No. of Sets Supplied Per Year = 20 Total Financial Saving Per Year = 154194x20 = Rs.30,83,880
If new fixture has to be developed and purchased from market, then it will costs = Rs. 6,00,000
Hence total saving will be = 30,83,880+6,00,000 = Rs.36,83,880

WE CLAIM
1. A drill jig fixture for drilling at a compound angle on a seal body of a
turbogenerator, the said drill jig fixture comprising;
a stepped base plate (10) having circularly arranged a plurality of tapped holes (16) on a stepped section (13) towards the center of the base plate (10) for rigidly locking the base plate to a sine table;
a plurality of key slots (19) provided towards the centre of the base plate (10) for holding the base plate to the sine table for restricting the rotary degree of freedom of the base plate/fixture (F);
a flange (11) machined on the circumferential edges for supporting the workpiece (20);
a plurality of circularly arranged threaded apertures (15) at a desired pitch circle diameter (d) (18) of stepped section (12) disposed for receiving the clamping bolts to lie in the slots (21) of the workpiece (20); wherein stepped sections (12, 13) are configured for providing supporting steps or collars to the work piece (20).
2. A method of drilling at a compound angle on a seal body of turbogenerator
comprising the steps of;

loosening the various connections (15, 16 and 19) between the workpiece and sine table to first provide the required angle to the base plate in one plane through sine table;
tightening the base plate (10) with the workpiece (20); wherein the drill is positioned relative to the drilling point and line of drilling relative to the workpiece (20) and compound drilling is then machined.