FIELD OF THE INVENTION
The present invention relates to a device for profile machining of axial
profile fan blades.
More particularly the present invention relates to a device capable of
configurating any desired-shaped profile on Fan Impeller blades.
BACKGROUND OF THE INVENTION
Fans are used to produce draught to the furnace or to handle the
pulverized fuel or to re circulate the flue gases or to provide cooling air for
various equipments in the thermal plants. The forced draught fan (FD)
provides atmospheric air for combustion and the induced draught fan (ID)
handles the products of combustion. Primary air fan (PA) handles cold
(atmospheric) or hot air to carry the pulverized fuel. Mill fans are used to
produce draught in the milling system and Gas recirculation fans (GR) re
circulate the flue gases to control the steam temperatures.
Axial fans are used in forced draught (FD) fan application and primary
air(PA) fan application in the thermal power plants. The axial profile fans
have specific design which are having the features of rotating the fan
blades to the required angle during running of the fan depending upon the
load requirements. This is enabled by a servo motor system.
The blades are generally made up of Aluminum Forgings. The forgings are
procured from the suppliers and machined to the required shape and size.
The locating dimensions in the blade boss are machined in a lathe. The
drilling and counter boring of holes for fixing the blades with the blade
shafts of the impeller are done in

the drilling machine. The profile cutting and length correction are done
manually by cutting and filing. Thus, the prior art manufacturing process
entail the disadvantage of manual operations for example, profile trimming
and length correction by cutting and filing.
OBJECTS OF THE INVENTION
It is therefore an object of the present invention to propose a device for
profile machining of axial profile fan blades which ensures positive contact
of the tracing roller including the backlash of the cutter.
Another object of the present invention is to propose a device for profile
machining of axial profile fan blades which is capable to swivel the base
which orients the components to the cutter.
A further object of the invention is to propose a device for profile
machining of axial profile fan blades which has means to suit the aerofoil
shape of the blade.
A still further object of the invention is to propose a device for profile
machining of axial profile fan blades which has means to suit the
component profile with a proper alignment and less friction, and is capable
to travel along the template in a self-determined tool path.
SUMMARY OF THE INVENTION
Accordingly there is provided a device for profile machining of axial profile
fan blades, comprising a vertical column mounted on a base, and
horizontally accommodating a rotatable main shaft a tool head (03)

mounted on the main shaft proximal to the vertical coloumn which guides the tool
head a cutter connected to the main shaft and driven by a drive unit a tracing roller
mounted at a distal end of the main shaft via a connecting rod a template mounted
on its base such that the tracing roller can slide over the template and have a
positive contact with the template via a spring-loaded means the spring-loaded
means mounted on the main shaft away from the vertical column and a swiveling
fixture accommodating a component to be profiled and orienting the component to
the cutter the component and the swiveling fixture being mounted on a feeding
means.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1- schematically shows the device including the component to be profiled.
Figure 2- is a pictorial view of the device during a profile-cutting operation.
DETAILED DESCRIPTION OF THE INVENTION:
The present invention is described herein below in detail with reference to the
accompanying drawing.
As shown in Figure 1, the device of the invention comprises a base (01) made up of
cast iron having intricate shape on which a vertical column (02) is mounted. The
vertical column (02) ensures the verticality and further guides a tool head (03). The
tool head (03) is having a tilting means, and is mounted on a main shaft (04) which
connects a cutter (05) and a tracing roller (08). The cutter (05) is a concave multi
tooth cutter. A spring loaded means (06) is mounted on the main shaft (04) which

ensures a positive contact of the tracing roller (08) with a template
(12). A connecting rod (07) connects the main shaft (04) and the
tracing roller (08). A reduction gear box 10) is coupled to a drive motor
(11) and a drive sprocket (09) to enable movement of the tool head
(03). The tracing roller (08) slides over the template (12) which is
mounted on a base (13) of the template (12), and forms a shape and
size to suit the profile of a component (14) with proper alignment and
less friction and further controls the movement of the tool path. The
component (14) is mounted on a swiveling fixture (15) which orients
the component (14) to the cutter (05). Both the component (14) and a
base of the swiveling fixture (15) is mounted on a feeding means (16).
The component (14) is mounted on the swiveling fixture (15)
corresponding to a reference mark provided on the base (01). The
template (12) is mounted on its base (13) vertically. Drive to be given
to the cutter (05) which forms the required radius over the profile. The
component (14) is moved towards the cutter (05) to enable the
machining. Depth of cut is given by the feeding means (16) to achieve
the required size. The cutter (05) is moved up and down through the
guide ways by the drive unit (09,10). The up and down movement upto
an ascending point and a descending point is controlled electrically by
timers and controls (not shown).
This novel arrangement and configuration of the device suit the aerofoil
shape of the blade (14).

We claim
1. A device for profile machining of axial profile fan blades, comprising:
- a vertical column (02) mounted on a base (01), and horizontally
accommodating a rotatable main shaft (04);
- a tool head (03) mounted on the main shaft (04) proximal to the
vertical column (02) which guides the tool head (03);
- a cutter (05) connected to the main shaft (04), and driven by a drive
unit (09,10,11);
- a tracing roller (08) mounted at a distal end of the main shaft (04)
via a connecting rod (07); characterized in that
- a template (12) mounted on its base (13) such that the tracing roller
(08) can slide over the template (12) and have a positive contact
with the template (12) via a spring-loaded means (06), the spring-
loaded means (06) mounted on the main shaft (04) away from the
vertical column (02); and a swiveling fixture (15) accommodating a
component (14) to be profiled and orienting the component (14) to
the cutter (05), the component (14) and the swiveling fixture (15)
being mounted on a feeding means (16).
2. The device as claimed in claim 1, wherein the tracing roller (08)
forms a shape and size to match a desired profile of the component
(14), and wherein the tracing roller (08) is configured so as to be
capable to smoothly travel along the template (12) and determine
the tool-path.

3. The device as claimed in claim 1, wherein the drive unit (9,10,11)
enables the cutter (05) to move vertically through the guide-way
determined by the tracing roller (08).
4. The device as claimed in claim 1, wherein the tool head (03)
comprises a tilting means.
5. A device for profile machining of axial profile fan blades as
substantially described and illustrated herein with reference to the
accompanying drawings.

ABSTRACT

Title: A DEVICE FOR PROFILE MACHINING
OF AXIAL PROFILE FAN BLADES
The present invention relates to device for profile machining of Axial Profile
fan blades comprising a vertical column (02) mounted on a base (01) and
accommodating a horizontal rotating main shaft (04), a tool head (03)
mounted on main shaft (04) holding cutter (05) and driven by a drive unit
(09,10,11), a tracing roller (08) mounted on the main shaft (04) via a
connecting rod (07) slides over a template (12) and have a positive contact
via a spring loaded means (06), a swiveling fixture (15) accommodating a
component (14) to be profiled and orienting the component (14) to the
cutter (05) wherein the component (14) and the swiveling fixture (15)
being mounted on a feeding means (16).