FORM 2
THE PATENT ACT  1970
(39 OF 1970)
AND
THE PATENTS RULES  2003

COMPLETE SPECIFICATION
(See Section 10; rule 13)

A FIXTURE CONFIGURATION FOR HOLDING T-ROOT BLANK AND
CLOSING BLADE BLANK SIMULTANEOUSLY
DURING MACHINING OPERATION

TRIVENI TURBINE LTD
an indian company 
of 12A  Peenya Industrial Area 
Banglore-560058.

The following specification particularly describes the present invention and the manner in which it is to be performed.
FIELD OF THE INVENTION:
The present invention relates to the field of fixture for holding blanks of blades. Particularly  the present invention relates to fixture to reduce work piece set up time.

BACKGROUND OF THE INVENTION:
The machining operation on the blanks of blades is carried out by mounting a fixture for holding the blanks on the base plate of the CNC Machine.

Figure 1(a) and 1(b) illustrates a conventional fixture configuration.

Figure 2 illustrates an enlarged view of base plate of figure 1.

Figure 3 illustrates an isometric view of T-root blank of figure 1.

Figure 4 illustrates an enlarged view of T-root blank holding fixture of figure 1.

Figure 5 illustrates an enlarged view of L-shaped clamp of figure 1.

Figure 6 illustrates an isometric view of closing blade blank of figure 1.

Figure 7 illustrates an enlarged view of closing blade blank holding fixture of figure 1.

The conventional fixture configuration comprises a base plate 12  a T-root blank 14  a T-root blank holding fixture 16  an L-shaped clamp 18  a closing blade blank 20  a closing blade blank holding fixture 22 and cylindrical bolts 24.

The T-root blank holding fixture 14 and the closing blade blank holding fixture 22 tencompasses grooves G1 and G2 of the T-root shape and closing blade root shape respectively. It is evident from figure 3 and figure 6 that the T-root blank 14 and closing blade blank 20 has flat surface on one side of the root and tapered surface on the other side of the root. A tapered surface complementary to the tapered surface of the root of the T-root blank 14 and closing blade blank 20 is provided on one side of the L-shape clamp 18 to facilitate in proper butting between both the surfaces.

In accordance with conventional fixture configuration  the T-root blank holding fixture 16 is placed on the base plate 12 of the machine and bolted by means of cylindrical bolts 24. A T-root blank 14 is placed in the groove G1 of the T-root blank holding fixture 16 and hold firmly in position with the help of the L-shaped clamp 18 placed over the T-root blank 14 on the surface of the T-root blank holding fixture 16 and bolted by means of cylindrical bolts 24.

As the T-root shape and closing blade root shape is different  the operator needs to change the T-root blank holding fixture 16 to closing blade blank holding fixture 22 for performing machining on the closing blade. The act of changing the fixtures (16 and 22) and setting up the work piece consumes a lot of time.

Therefore  there is a felt need for development of a fixture configuration to reduce the cycle time of performing machining operation on the closing blade.

OBJECTS OF THE INVENTION:
An object of the present invention is to provide a simple fixture for holding T-root blank and closing blade blank simultaneously.

Another object of the present invention is to reduce the complexity of the job and thereby reduce the workload on the operator.

One more object of the present invention is to reduce the cycle time of performing machining operation on the closing blade.

BRIEF DESCRIPTION OF THE DRAWINGS:
The invention will now be described with reference to the accompanying drawings in which:

Figure 1(a) and 1(b) illustrates a conventional fixture configuration;

Figure 2 illustrates an enlarged view of base plate of figure 1;

Figure 3 illustrates an isometric view of T-root blank of figure 1;

Figure 4 illustrates an enlarged view of T-root blank holding fixture of figure 1;

Figure 5 illustrates an enlarged view of L-shaped clamp of figure 1;

Figure 6 illustrates an isometric view of closing blade blank of figure 1;

Figure 7 illustrates an enlarged view of closing blade blank holding fixture of figure 1;

Figure 8 illustrates a new fixture configuration in accordance with the present invention;

Figure 9 illustrates an enlarged view of the fixture of figure 8;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS:
Figure 8 illustrates a new fixture configuration. In accordance with the present invention  there is provided a new fixture configuration comprising a base plate 32  a T-root blank 34  a T-root blank and closing blade blank holding fixture 36  two L-shaped clamps 38  a closing blade blank 40 and cylindrical bolts 42.

Figure 9 illustrates an enlarged view of the fixture of figure 8.

The T-root blank and closing blade blank holding fixture 36 encompasses grooves G3 and G4 of the T-root shape and closing blade root shape respectively. It is evident from figure 9 that the T-root blank 34 and closing blade blank 40 has flat surface on one side of the root and tapered surface on the other side of the root. A tapered surface complementary to the tapered surface of the root of the T-root blank 34 and closing blade blank 40 is provided on one side of the two L-shape clamps 38 to facilitate in proper butting between both the surfaces.

In accordance with new fixture configuration  the T-root blank and closing blade blank holding fixture 36 is placed on the base plate 12 of the machine and bolted by means of cylindrical bolts 42. A T-root blank 34 and closing blade blank 40 are placed in the grooves G3 and G4 of the T-root blank and closing blade blank holding fixture 36 respectively and hold firmly in position with the help of the two L-shaped clamps 38 placed over the T-root blank 34 and closing blade blank 40 on the surface of the T-root blank and closing blade blank holding fixture 36 and bolted by means of cylindrical bolts 42.

The T-root blank and closing blade blank holding fixture 36 eliminated the need for change of fixtures for machining the closing blade blank 40 and thereby reduced the workpiece set up time.

A slight modification in computer numerical control code (CNC code) is done to accommodate the changes made in the fixture.

Although the invention has been described herein above with reference to the embodiments of the invention  the invention is not limited to the embodiments described herein above. It is to be understood that modifications and variations of the embodiments can be made without departing from the spirit and scope of the invention.

We claim:
1) A fixture configuration for holding T-root blank and closing blade blank simultaneously during machining operation  said fixture configuration comprising:
a) a T-root blank and closing blade blank holding fixture encompassing a T-root groove and closing blade blank root groove for holding a T-root blank and closing blade blank respectively having threaded holes around the perimeter of said fixture;
b) a base plate mounted and bolted on a CNC machine having complementary threaded holes to mate with the threaded holes of said fixture  said fixture mounted on said base plate and bolted by means of cylindrical bolts; and
c) two L-shaped clamps placed over the surface of said T-root blank and closing blade blank holding fixture with one clamp mounted on said T-root blank and bolted and the other clamp mounted on said Closing blade blank and bolted.

2) A fixture configuration for holding T-root blank and closing blade blank simultaneously during machining operation as claimed in claim 1  wherein said L-shaped clamps facilitate in holding said T-root blank and closing blade blank in said T-root groove and closing blade blank root groove of said fixture firmly in position during machining operation.

Dated this 22nd day of May  2012 (for Triveni Turbine Ltd)


Dr.Sunil Jajit
GM-IPR