FIELD OF INVENTION
The present invention relates to rigid and uniform clamping of turbine blades for
chamfer cutting. More particularly the invention relates to a device for clamping
of steam Turbine blades T4/Tx type to undertake chamfering operation in single
setting instead of double setting which was undertaken as per previous practice.
BACKGROUND OF THE INVENTION
Steam turbine blade is a very precise and critical component. At present, the
blades are butt on the horizontal position and chamfer is done on one side of the
blades, and then on the other side chamfer is done by changing the position of
blade. Now in the present invention, the blades are places in the vertical
positioned and then chamfering operation is done on both the sides in single
setting.
As per previous practice it is used to take an enormous amount of time to
undertake chamfering operation. Further due to change of setting, the accuracy
of the job in terms of quality was also affected besides increase of setting time in
between consecutive operations leave aside other indirect expenditure. The
present invention overcomes all these drawbacks.
OBJECTS OF THE INVENTION
The object of the present invention is to develop a device for clamping of steam
Turbine blades T4/Tx'type to undertake chamfering operation on both sides in
single setting instead of the double setting of the previous practice.
Another object of the invention is to develop a device for clamping of steam
Turbine blades T4/Tx type to undertake chamfering operation in single setting
which will shorten the total chamfer cutting time of the blades.

A further object of the invention is to develop a device for clamping of steam
Turbine blades T4/Tx type to undertake chamfering operation in single setting
which will shorten the setting time of blades for chamfer cutting.
SUMMARY OF THE INVENTION
Accordingly, there is provided a clamping device for cutting chamfer of steam
turbine blades in single setting comprising:
a) clamping stand (1)
b) wedge plate for slot size (2)
c) screw (5) for clamping wedge (2) and angel plate (6)
d) steam turbine blade (4)
e) machine tablet (3)
f) Angle plate (6)
The blades are held vertically on the clamping stand where the wedge fits into
the slot of the blade. The angle plates give rigidity and support to the blades
while the chamfering operation is done on the root of turbine blade in single
setting.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig.1 shows the vertical clamping units (left and right)
Fig.2 shows the wedge according to the slot size of the blades.
Fig.3 shows the angle plates to give rigid support to the blade.
Fig.4 clamping device for holding the turbine blade
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT OF THE
PRESENT INVENTION
Fig 4 shows the clamping device for holding the turbine blade.
The set up holds the turbine blade vertically with root side at the top and shroud
side at the bottom. The clamping stand (1.) are fixed vertically on the machine
table (3) with the help of the counter hole by the screws (5).

The wedge plates (2) are fixed to the clamping stand (1) by means of screws
(5). The blades (4) are then held by the wedge plate (2) which fits into the slot
provided in the turbine blades.
The slit provided in the wedge plate (2) acts as a spring action. The chamfering
in the outer dimension of wedge plate (02) allows the wedge plate to move
smoothly in the slot of the turbine blade so that the holding is tight as well as
maintaining a reference line of the turbine blade. If the blade slot is 20 mm, then
the wedge size (outer) should be 19.5 mm with 1mm slit on the wedge. The
chamfer on the wedge will easily allow it to enter into the slot of the turbine
blade and due to spring action of the wedge plate it will be held tightly.
To give rigid support to the blade (4), angle plates (6) are to be used as per the
blade rhomboidal angel at both sides i.e. inlet and exit side of the blade.
Generally 17°, 19°, 21°, 23° and 25° to be used in the blades.
After clamping the blade on the machine table (03) in vertical position, the first
chamfer is cut and, then the table position is moved or offset for second chamfer
cut on the other side.

WE CLAIM:
1. A device (A) for clamping of steam Turbine blades T4/Tx type to undertake
chamfering operation in single setting comprising:
a machine table (03);
a plurality of clamping stand (01) erected vertically on the base (03) by clamping
screw(05);
a plurality of wedge plates (02) having slit in it are fixed on vertical clamps (01)
by screws (05);
angle plates (06) are clamped on the Machine table which give rigidity and
support to the blades.
characterized in that the turbine blades are placed in vertical position when the
wedge plate fits into the blade slot gripping the blades tightly and firmly due to
spring action of the wedges, where the chamfer provided on the outer side of
wedge allows the wedge to move with slide fit into the blade slot.
2. The device (A) as claimed in claim 1 wherein the wedge plates (2) are
provided with slit to impart spring action during holding in the turbine blade slot.
3. The device (A) as claimed in claim 1 wherein the wedge plates (2) are
provided with chamfer at the edges for easy entering into the slots.
4. The device as claimed in claim (1) wherein plurality of angle plates (06) are
fixed in machine table to give rigidity and support to the turbine blades (04)
while performing the chamfer cut in the turbine blade.

5. The device (A) as claimed in claim 1, wherein the angles of the plates are 17°,
19°, 21°, 23° and 25° to match the blade rhomboidal angle at both the inlet and
exit side of the blade.

ABSTRACT

A device (A) for clamping of steam Turbine blades T4/Tx type to undertake
chamfering operation in single setting comprising:
a machine table (03);
a plurality of clamping stand (01) erected vertically on the base (03) by clamping
screw(05);
a plurality of wedge plates (02) having slit in it are fixed on vertical clamps (01)
by screws (05);
angle plates (06) are clamped on the Machine table which give rigidity and
support to the blades.
characterized in that the turbine blades are placed in vertical position when the
wedge plate fits into the blade slot gripping the blades tightly and firmly due to
spring action of the wedges, where the chamfer provided on the outer side of
wedge allows the wedge to move with slide fit into the blade slot.