FIELD OF THE INVENTION
The present invention reiates to fixture that faciiitates drilling of end shield Joint plane holes in a turbo generator.
More particularly the present invention relates to damping fixture which facilitates the drilling of joint plane holes on the end shield of a turbo generator. on radial drill machine in such a way that the time consumed in repeated angling, turning and rotation during drilling of holes can be minimized.
BACKGROUND OF THE INVENTION
A turbo generator is the combination of a turbine directly connected to an electric generator for the generation of electric power. The generator consists of two main parts, a Stator and a Rotor.
A generator end shield is mounted at both ends of a cylindrical power generator to support the power generator rotor bearing and is equipped with an oil deflector and a hydrogen seal casing to prevent leakage.
The generator end shields are heavily reinforced fabrications, designed to support the weight of the rotor and to contain the hydrogen gas at maximum pressure without excessive distortion.
The generator rotor bearing, the hydrogen shaft seals, and oil passages supplying oil to different parts, are contained and/or supported by the outer end shield The end shields are split on the horizontal centre line, facilitating their removal. The joints between the end shield halves, between the metal shields and the stator frame are fitted and provided with groove for the insertion of a sealing compound to seal the generator gas in the generator casing.

in other words, generator end-shield generally serve multiple purpose. They act as the end seals of a cylindrical pressure vessel at both ends of the generator, since a higher rating generator could be operating under huge hydrogen pressure. The end shields also act as a support to the hydrogen seals and the rotor as end shield bearing are employed in them.
Because of the nature of the stator construction, the end shields are designed in two halves, a lower and an upper. This is done for the ease of installation and removal of the rotor and the end shields themselves, as well as the other components attached to them. This arrangement of half end shields also poses a requirement to sealing the face of the stator casing, and around the hydrogen seals and bearing housing and most importantly to seal them at their half joints.
For sealing the joint plane of the end shield, there are plurality of joint plane holes provided on the face of the joint plane. These holes are currently made using CNC horizontal boring machine since end shield requires accurate drilling of joint plane holes and specific tests to guarantee proper functioning.
As per prior art, there are NC codes for marking and drilling of these end shield joint plane holes and both these operations are performed on a CNC Horizontal Boring Machine (HBM) which is a costly machine to perform simple operations like drilling.
While using the horizontal boring machine, there was no requirement of fixture as the half end shield was put on the machine bed and the dimensions and reference are made by the spindle of the CNC machine.
Therefore the present invention replaces the use of a (HBM) machine for doing such type of jobs which at one end need accuracy in job requirement, while on the other hand replaces job engagement in a machine where machine hour cost is very high.

OBJECTS OF THE INVENTION
An object of the invention is to develop fixture for supporting end shield of turbo generator during drilling of holes on joint plane on radial drill machine on which the end shield can be mounted firmly, locking its movement so that it does not vibrate/dislocates from its position while drilling of sealing holes on the joint plane of the end shield.
Another object of the invention is to develop fixture for supporting end shield of turbo generator during drilling of holes on joint plane on radial drill machine which facilitates drilling of sealing holes on the joint plane on a normal drilling machine thereby eliminating the use of horizontal boring machine which is a costly manufacturing option.
Yet another object of the invention is to develop fixture for supporting end shield of turbo generator during drilling of holes on joint plane on radial drill machine which rigidly holds the end shield in a way that there is no damage in the already machined end shield.
A still another object of the invention is to develop fixture for supporting end shield of turbo generator during drilling of holes on joint plane on radial drill machine which can be easily adjusted to make the joint plane parallel to the machine bed.
A still another object of the invention is to develop fixture for supporting end shield of turbo generator during drilling of holes on joint plane on radial drill machine that can easily support the forces of drilling that is transferred while drilling of joint plane holes.
A still another object of the invention is to develop fixture for supporting end shield of turbo generator during drilling of holes on joint plane on radial drill machine that can be used for drilling of joint plane holes of end shield of different rating of turbo generator.

SUMMARY OF THE INVENTION
According to the present invention, there is provided a fixture (F) for supporting one half of the end shield (16) during drilling of holes on joint plane comprising of a horizontal base (1) on which a vertical support (2) is mounted. The end shield is mounted in such a manner that the joint plane is towards the top.
A hydraulic jack ram is attached to the plate (15) integral to the end shield (16) while the plate (15) rests on the plate support (9).
Plurality of gussets (3) are welded on the base (1) and vertical support (2) in order to strengthen vertical support (2).
To pick and place the fixture (F) on the machine bed, holes are provided on lifting hooks (4).
Half end shield is completely supported on fixture (F) in a way that the semi¬circular periphery of the end shield (16) rests on plurality of rollers (14) and thus end shield can rotate about its centre axis.
End shield (16) after final adjustments is clamped rigidly at its position using clamps (12).
For different rating of turbo generator, size of end shields are different and to accommodate the variation of size, rollers (14) will be placed in the plurality of threaded holes for roller (5, 11, 13) and thereupon accordingly three threaded holes (6, 7, 8) are provided for clamping the half end shield.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as

hereinafter described and claimed, reference being made to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which;
Figure 1: Perspective view of the fixture for supporting end shield of turbo generator during drilling of holes on joint plane on radial drilling machine constructed in accordance with the present invention;
Figure 2: Photographic view of end shield halves
Figure 3: Photographic view of end shield joint plane
Figure 4: Photographic view of fixture to machine end shield joint plane
Figure 5: Holding of plate (15) by hydraulic ram.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the flgure-1 in detail, it will be seen that the embodiment of the invention which has been illustrated comprises of:
1: Base of the fixture
2: Vertical support
3 : Plurality of Gussets
4 : Plurality of holes for lifting hooks
5,11,13 : Plurality of threaded hole for roller (14) 6, 7, 8 : Plurality of threaded hole for clamp (12)
9 : Plurality of plate for end shield support (2)
10 : Plurality of bolt for threaded connection
12 : Clamp
14: Roller
15: Plate integral to the end shield (16)

The description of the fixture is briefed as per the following details:-
Base (1) serves as the base of the fixture. It gives the stability to the whole fixture (F) when the end shield (16) is mounted on the fixture (F). Base of the fixture (1) also gives the stability as it is wide enough to easily ground and damp the vibrations that come as a result of drilling of the joint plane holes in end shield (16).
Vertical support (2) is welded on the base (1) of the fixture (F) in vertical direction. The idea behind keeping the support (2) for end shield (16) vertical is because of two reasons:
a) To accommodate the large size of the end shield (16).
b) To help in keeping the joint plane (AA) of the end shield (16) towards the top direction.
All the clamping and holding arrangement are provided on this vertical support (2).
Gussets (3) are triangular shaped ribs (thin wall protrusions that extend perpendicularly from a wall or plane surface) welded to Base (1) of the fixture (F) and vertical support (2), thereby adding strength and rigidity to vertical support (2) avoiding excessive thickness of vertical support (2) which may otherwise cause sinking and warpage. Gussets (3) solve this problem by providing additional support to the vertical support (2) and are in fact, structurally more effective than just a thick wall.
The end shield is picked using the holes (4) for lifting and is placed/mounted on the fixture (F) and is supported additionally by:-
a) plurality of rollers (14) placed on the same horizontal plane lying in the same height from the base of the fixture (F);
b) plurality of support plates (9) provided on both left and right hand side of the fixture.

End shield (16) is placed on the fixture (F) in a way that the semi-circular periphery of the end shield rests on plurality of roller (14) and the plates (15) integral to end shield rests on the support plate (9) located at the back of the fixture and thus end shield (16) can rotate about its centre axis.
Rollers (14) are used as a support mechanism because of the reasons that:
a) The end shield has a semi-circular periphery;
b) It is always easy to adjust the position of end shield on rollers (14) as the weight of the end shield is huge;
c) Rollers (14) eliminate the repeated use of EOT cranes for fine adjustments of the end shield for paralleling joint plane to the machine bed.
The ram of hydraulic jacks is affixed to the plates (15) integral to the end shield on both left and right side of the end shield (16) (refer fig.2 and fig. 5). The plates (15) integral to the end shield will be supported by support plates (9) provided on the fixture (F). The plates (15) which are integral to the end shield, are present on both left hand and right hand side of the end shield and located below the joint plane. When end shield (16) is placed on the fixture (F), the plate (15) will be in butt condition with the plate support (9). The plate is shown in the figure 2. If the joint plane (AA) of the end shield are not parallel to the base of the machine, the hydraulic jack will be adjusted in their heights to make the joint plane parallel to the bed of the drilling machine (fig.5).
Clamps (12) are provided for holding the end shield (16) rigidly at its place after adjustment through plurality of bolted connections (10).
To make the fixture (F) versatile in a way that the same fixture can be used for drilling of joint plane holes in end shield (16) of different rating of Turbo generator, different threaded holes for rollers (5, 11, 13) are used and similarly threaded holes for clamps (6, 7, 8) are provided.

The rollers (14) and clamps (12) make numerous combinations with threaded holes for roller (5,11, 13) and threaded holes for clamps (6, 7, 8) to accommodate various end shield sizes and further threaded holes can be made in the fixture (F) to accommodate any new size.
Accordingly, the job is accurately clamped to serve the object of the invention by the use of above mentioned fixture as per following steps:
Step-1: Place the complete fixture (F) at its base (1) on the machine bed using a crane that lifts the fixture (F) using lifting hooks (4).
Step-2: It has to be confirmed that the machine is properly levelled in accordance with the manufacturer's instruction which may consist:-
a) Perpendicularity of drill head guide to the base of the machine.
b) Perpendicularity of spindle sleeve with base of the machine.
c) Parallelism of spindle axis with its vertical movement.
Step-3: Unhook and to take the crane away after the placement of fixture (F) on the machine bed and use the same crane/or any other crane to place one half of the end shield (16) on the plurality of rollers (14) provided on the vertical support (2) of the fixture (F) in such a way that the joint plane (AA) of the end shield (16) is directed in upward direction. Identify the rating/size of the end shield (16) and tighten the end shield (16) so that rollers (14) are placed suitably in threaded hole (5,11,13).
Step-4: Ensure that the plate (15) integral to the end shield (16) is supported by the plurality of support plate (9).
Step-5: Stepped segments (SS) are provided to accommodate the extruded portions of the end shield (16) as per design of the end shield and these stepped section accommodate all kinds of extrusions of all rating of end shield. But it is to be noted that since the variation in the design of the end shield is endless therefore the changes in fixture and specially the stepped segment (SS) will have to be made accordingly.

Step-6: Ensure that the joint plane (AA) (on which the drilling of holes is to be done) is parallel to the machine bed using a dial indicator affixed in the spindle of the machine e.g., if suppose the right hand side joint plane is toward the up side and the left hand side joint plane is towards the lower side, the axis of the joint plane will not remain parallel to the axis of the machine.
In this case, ram of a hydraulic jack attached to left side integral plate (15) of the half end shield will be pushed in upward direction and the ram of the hydraulic jack attached to right side integral plate (15) of the half end shield will be pushed in downward direction.
During this process, the left hand side joint plane will move up.
The dial indicator is fixed to the spindle of the drilling machine and the feeler of the indicator touches the joint plane surface (AA). The spindle of the machine holding the dial indicator will be moved over the joint plane.
If the indicator shows some deflection, it means that the joint plane is not
parallel to the machine bed and further adjustment using jack is necessary.

This process is reiterated till the time dial indicator does not show any deflection and the joint plane is parallel to the machine bed. This indicates that the joint plane on which drilling is to be performed are parallel to the machine bed and perpendicular the spindle of the machine.
Step-7: Identify the rating/size of the end shield and tighten the end shield using clamp (12) through a bolt (10). If we don't clamp the end shield at its position and remove the jack after the joint plane is made parallel to the machine bed, the center of gravity of end shield will shift and will generate torque (turning effect of force) and will force the end shield to rotate. This rotation will again cause the joint plane to mismatch the parallelism with machine bed.

Thereby in order to hold the end shield in a position where its joint plane are
parallel to machine bed, clamps (12) are used to temporarily fasten, hold and
secure end shield tightly using bolt (10) in threaded hole (7) to prevent
movement through the application of drilling pressure and vibration during
drilling of joint plane holes.
Thus the drilling of the joint plane holes can be performed after clamping of end shield on the markings of that were made during the drilling of joint plane holes.
Practically to accommodate different size of end shields pertaining to different ratings of turbo generators, threaded holes for clamps (6, 7, 8) and threaded holes for roller (5, 11, 13) are provided on the fixture which completely rules out using different fixtures and multiple settings which thereby eliminates increased cost and time of drilling joint plane holes.
Also, for easy manoeuvrability of the fixture (F), hooks (4) provided to be used with cranes to shift the fixture from one place to other as per convenience.
Additionally, stepped segments (SS) are provided to accommodate the extruded portions of the end shield as per design of the end shield and these stepped section (SS) accommodate all kinds of extrusions of all rating of end shield but it is to be noted that the variation in the design of the end shield is endless and similarly the changes in fixture and specially the stepped segment (SS) will have to be made.

We Claim

1. A fixture for supporting end shield of turbo generator during drilling of holes on joint plane comprising:-
- a horizontal base (1);
- a vertical support (2) welded on the horizontal base (1);
- a plurality of gussets / ribs (3) of triangular shape welded with one side
on horizontal base (1) and with other side on vertical support (2) for
strengthening the vertical support (2) without increasing weight;
- a plurality of plates (9) welded on vertical support (2) on either sides for providing support to plate (15) integral attached to end shield (16);
- a plurality of rollers (14) disposed on threaded holes (5, 11, 13) in pairs on either side of vertical support (2) for taking the load of the end shield (16) by holding from either side of semi-circular periphery wherein;
- rams of a plurality of hydraulic jacks are affixed to the plate (15)
integral of the end shield (16) from either side characterized in that
the excess load of the end shield (16) are distributed and taken by the
moveable rollers (14) wherein the end shield is rotatable about the
central axis when the parallelism of the joint plane of the end shield
with respect to the machine bed is accomplished by adjusting the
height of hydraulic jack accordingly by moving a dial indicator feeler on
the joint plane (AA) of end shield.

2. The fixture as claimed in claim 1, wherein the threaded holes (5,11,13) are provided on either side of vertical support (2) for fixing of rollers (14) which lend support to the end shield.
3. The fixture as claimed in claim 1, wherein threaded holes (6, 7, 8) are provided in vertical support (2) where clamps (12) are fitted for clamping the end shield after adjustment is completed.
4. The fixture as claimed in claim 1, wherein the support (2) is provided with stepped segments (SS) for accommodating all kind of extrusions of end shield.
5. The fixture as claimed in claim 1, wherein the vertical support is provided with lifting hook (4) for lifting of the fixture by EOT crane.
6. A method for holding and clamping an end shield (16) of a turbo generator in a fixture as claimed in claim 1 comprising:-

- lifting of the fixture (F) by holding on the hole of the lifting hook (4) by a crane and placing it on the machine bed;
- adjusting the roller (14) in the plurality of threaded holes (5, 11, 13) according to the size variance of end shield that will be placed on the fixture;

- placing the end shield (16) on the fixture by a crane such that the
semi-circular periphery of the end shield rest on plurality of rollers (14)
when the plate (15) integral of end shield (16) rest on the support
plate (9) located at the back of fixture such that the end shield can
rotate about its central axis;
- checking the parallelism of joint plane (AA) with machine bed by
moving a dial indicator feeler affixed in the spindle along the joint
plane (AA);
- adjusting the hydraulic jack in their height up and down on either side of end shield till the joint plane (AA) is parallel to the machine bed;
- clamping the end shield (16) on either side by plurality of clamps (12) fixed on threaded holes (6, 7, 8) as per different size variance of end shield;
- performing the drilling operation in the joint plane (AA) of the end shield;
- unclamping and lifting the job by a crane after the machining
operations are completed for starting the next job.