FIELD OF THE INVENTION;
The present invention generally relates to a CNC-facing lathe machine adapted
for machining several sizes of discs normally used in gas turbine. More
particularly, the invention relates to an improved locking system to hold longer
and heavier jobs on a CNC-facing lathe for machining.
BACKGROUND OF THE INVENTION:
A CNC facing lathe can be installed in a turbine block when discs of different
stages for gas turbine rotor are required to be machined. Three sets of jaws are
normally provided for the machine to hold the discs of different lengths. A
locking system for the Jaws is generally provided to lock the jaws after final
setting of the discs to prevent backward movement of the jaws due to
gravity/cutting forces generated while undertaking the machining process.
Due to wear and tear of the locking system for a long time, the locking capacity
of the system gets reduced, and accordingly long jobs cannot be taken up for
machining.
All the set of jaws have each a locking means for fixing the job at its last and
final setting, (locking assembly shown in the picture) to provide a firm grip on
long and heavy jobs.
After placing the job on the machine and subsequent to the final setting, the
movement of the jaws are initiated by operating a hexagonal nut with a torque
wrench which pushes an actuating shaft causing a downward movement of the

assembly. This operation locks the jaw tightly. The torque wrench is however set
at a required magnitude before the tightening which ensures application of a
desired force.
DISADVANTAGES OF PRIOR ART
1. Due to wearing out of the locks, jobs of substantially smaller length for
example, 200-300 mm long can be machined on a CNC facing lathe, which
interalia restricts the optimum capacity utilization of the machine.
2. In the locking assembly, frequent damage of components in particular the
lever results in increased number of machine breakdowns.
3. CNC Facing lathe is one of the highly critical machine with a substantially
higher per hour running cost. The under utilization of the machine due to
frequent wear of the locking system result in increased overheads.
4. Limitations of job-size seriously affects the productivity.
OBJECTS OF THE INVENTION:
It is therefore an object of the invention to propose an improved locking system
to hold longer and heavier jobs on a CNC-facing lathe for machining, which
eliminates the disadvantages of prior art.
Another object of the invention to propose an improved locking system to hold
longer and heavier jobs on a CNC-facing lathe for machining, which substantially
reduces frequent break-down of the machine.

A still another object of the invention to propose an improved locking system to
hold longer and heavier jobs on a CNC-facing lathe for machining, which
eliminates the limitation of size and weight of the job for machining.
A further object of the invention to propose an improved locking system to hold
longer and heavier jobs on a CNC-facing lathe for machining, which increases the
capacity utilization vis-a-vis productivity of the high cost CNC facing lathe
machine.
A still further object of the invention to propose an improved locking system to
hold longer and heavier jobs on a CNC-facing lathe for machining, which is
simple, cost-effective, and long-lasting.
SUMMARY OF THE INVENTION:
The present invention is provided with an improved device for locking of Jaws on
a CNC-facing lathe for machining of longer and heavier components comprising a
cylindrical pin disposed on central part of the face plate of the Jaws; a multi-
dimensional long locking pin having a square head part at first end and a long
threaded portion at the second end; characterized in that a clockwise turning of
the locking pin by a torque wrench enables the cylindrical pin to axially move in
forward direction which in turn locks the Jaws.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Fig. 1 - A schematic diagram of locking pin as per new invention.

Fig. 2 - A schematic diagram of cylindrical pin as per new invention.
Fig. 3 - A schematic diagram of assembly of cylindrical pin and locking pin inside
the Jaw's face plate.
Fig. 4 - A photo view of a locking pin and a torque wrench.
Fig. 5 - A photo view showing the damage locking assembly as per prior art.
Fig. 6 - A schematic diagram showing the locking assembly as per prior art.
BRIEF DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION;
The present invention is provided with a cylindrical pin (4) having 57 mm
diameter and 85 mm length disposed at the central part of a Jaw's face plate,
and a long multi-dimensional locking pin (2) having a length of 144 mm out of
which 50 mm length is a square shaped part at first end (5) then; a collar of 27
mm diameter and 5 mm length then; a plane cylindrical shape (7) of 16 mm
diameter and 35 mm length then; a relieving part (8) of 12 mm diameter and 4
mm length then; a threaded part (9) having 12 mm diameter and 48 mm length
at second end.
The central pin and locking pin are made alloy steel material. The cylindrical pin
is placed inside the central part of the Jaw's face plate (10) and the locking pin
(2) is inserted through a hexagonal socket (1) of the Jaw's and a clockwise
rotation of locking pin is imparted by a torque wrench (11) fitted at square head
(5) of the locking pin (2) which enables the locking pin to move axially through
the threaded part (3) of the Jaw's face plate (10) and finally the locking pin
pushes axially the cylindrical pin (4) which locks the Jaws movement.

WE CLAIM:
1. An improved device for locking of Jaws on a CNC-facing lathe for
machining of longer and heavier components comprising:
a cylindrical pin disposed on central part of the face plate of the
Jaws;
a multi-dimensional long locking pin having a square head part
at first end and a long threaded portion at the second end;
characterized in that a clockwise turning of the locking pin by a torque
wrench enables the cylindrical pin to axially move in forward direction
which in turn locks the Jaws.
2. The locking device as claimed in claim 1, wherein the locking pin and the
cylindrical pin are made of alloy steel materials.
3. The locking device as claimed in claim 1, wherein the cylindrical pin is 85
mm in length and 57 mm in diameter.
4. The locking device as claimed in claim 1, wherein the locking pin is 144
mm comprising
(i) a square shaped part of 50 mm at First end then;
(ii) a collar 5 mm length with 27 mm diameter;
(iii) a plane cylindrical shaped part of 35 mm length with 16
mm diameter;
(iv) a relieving part of 4 mm length with 12 mm diameter;
(v) a threaded part of 48 mm length with 12 mm diameter
disposed at second end.

5. The device for locking of Jaws on a CNC-facing lathe for machining of
longer and heavier components as substantially described and illustrated
herein along with accompanying drawings.