FIELD OF THE INVENTION
The present invention relates to a development of hydraulic clamping fixture for doing rework on a variety of finished turbine blades in vertical Milling Machine.
More particularly, it relates to development of support clamp fixture having hydraulic action for rigidly clamping the root and shroud portion of any type of blade for doing rework in vertical milling machine.
BACKGROUND OF THE INVENTION
In a machine shop various type of steam turbine blades like Tx, 3DS, F&Z types are machined regularly. These blades process through self-inspection and as welt as final stage inspection. In Final/Intermediate stage of inspection, it has been found after machining operation that few blades have some dimensional variation like 'z' shroud radius, 'T' slot Width, 'Shoulder steps' and 'End Chamfer' etc, and finally get rejected. These may be due to the following reasons.
1) Improper re-sharpening of cutter
2) Machine alignment not ok
3) Higher cutting tool parameter
4) Delay in changing/indexing the tools etc. Over a period of time these rejected blades become huge in number and beyond repair.
In order to overcome the problem, a hydraulic clamping fixture has been developed which can accurately hold the root and shroud portion rigidly in Vertical milling machine to carry out the minor rectification work in finished blade.

OBJECTS OF THE INVENTION
The object of the present invention is to develop a hydraulic clamping fixture for finished blade which can rigidly clamp the blade with the application of hydraulic pressure.
Another object of the invention is to develop a hydraulic clamping fixture for finished blade which can carry out the rectification more easily on rejected finished blade.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig. 1.1 - Shows the turbine blade
Fig. 1.2 - Shows the Isometric View of Hydraulic Clamp Fixture
Fig. 2 - Shows the Assembly Drawing
Fig. 3 - Shows the Fixture Base
Fig. 4 - Shows the Sliding Unit (RH)
Fig. 5 - Shows the Sliding Unit (LH)
Fig. 6 - Shows the Clamping Arm
Fig. 7 - Shows the Taper Pad
Fig. 8 - Shows the Locking Pin
Fig. 9 - Shows the Hydraulic Cylinder Guide
Fig. 10 - Shows the Height Adjusting Pad
Fig. 11 - Complete Fixture in Blade Clamping Position with Hydraulic Clamping

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
The hydraulic fixture (F) fig.l comprising a base frame (1) fig.3, measuring 492mm x 130mm x 80mm approximately having a slot, a pair of sliding units, RH (2) fig.4 and LH (3) fig.5 mounted on the base such that they can slide over the slot along the length of the base (1) and can be set according to the length of turbine blade. Base of the sliding unit LH (3) fig.5 have different design than that of sliding unit RH (2) fig.4. In LH sliding unit (3) fig.5 a slot is made on which height adjusting block (8) fig. 10 is mounted over which one end of the blade rest and other end of the blade is rests at RH sliding unit (2) fig.4. Back of both the sliding unit (2) 2(3) fig.4 & fig.5 is fitted with hydraulic cylinder (9) and hydraulic cylinder passes through cylinder guide (5) fig.9. Clamping arm (4) fig.6 attached with sliding unit (2 & 3) fig.4 & fig.5 through locking pin (7) fig.8. Two number of taper pad (6) fig.7 are attached with each sliding unit (2 & 3) with a bolt. Blade rest at this taper pad (6) fig.7 which restrict the motion of blade cross the fixture base fig.3. Both LH & RH sliding unit restrict the motion of blade along the length of the fixture base (5) fig.3. On actuation of hydraulic clamping mechanism, clamping arm (4), push the blade (10), downward at the ends of blade and restrict the upward motion of the blade. Now the blade is clamped on new hydraulic clamp fixture to carry out the machining operation on finish blade.

We claim:
1. A hydraulic clamping fixture for holding finished turbine blade comprising:
a plurality of Right hand (RH) (2) and Left hand (LH) (3) sliding units mounted on a base (1) having slots such that the units (2,3) can slide over the base according to the length of the turbine blade (10) being hold as a job;
a height adjusting block (8) disposed on the left hand sliding unit (3) for adjusting the height of the job to be machined wherein the job rest with one end on the block (8) while the other end over the right hand sliding unit (2);
a plurality of taper pad (6) further disposed with the sliding units (2,3) by bolts for providing additional support from both sides;
a plurality of clamping arm (4) attached with the sliding units (2,3) for locking the job through locking pins (7) characterized in that the fixture is equipped with a hydraulic clamping mechanism for actuating the clamping arm (4) to push the blade downward restricting the upward motion, whereas the right hand and left hand sliding units (2,3) restrict the longitudinal movement while taper pads (6) restrict the cross movement.