FIELD OF INVENTION
The invention relates to a device in the field of machining of jobs.
In particular the invention relates to a device for drilling holes on the
vertical surface of a cylinder at different angles as well as different
heights.
BACKGROUND OF THE INVENTION
It had been designed for the immediate requirement for accurately
drilling holes on the vertical surface of fibre glass cylinders of 'On Load
Tap Changer', a product being used on power transformers. But it can be
used for drilling holes on any other cylinder where holes are required to
be drilled at different angles and heights.
Earlier holes were drilled through a general purpose arrangement by
placing the job on a rotary table and drilling the holes at the required
angles and heights through use of rotary table and height gauge for
locating the position where a hole was required to be drilled. However,
there were always problems with the accuracy for the relative position of
holes. As a result there were problems during the assembly. Hence, it was
decided to look for new alternatives and special purpose solution. The
idea of pre-drilled horizontal Index Plates was conceived. The details
were worked out and required arrangement was designed, manufactured
and tested. Thus the problem of inaccuracy in the relative position of
holes was completely eliminated as the index plates were accurately pre-
drilled. As it is a special
purpose solution, a new Index Plate would be required for each new set
of holes.
OBJECTS OF THE INVENTION
It is therefore, an object of the present invention to propose a
device for drilling holes on the vertical surface of a cylinder at different
angles as well as different height which eliminates the disadvantages in
prior arts.
Another object of the present invention is to propose a device for
drilling holes on the vertical surface of a cylinder at different angles as
well as different height which enables perfection of holes in right
position.
A further object of the present invention is to propose a device for
drilling holes on the vertical surface of a
cylinder at different angles as well as different height which saves cost of
production.
An yet further object of the present invention is to propose a device
for drilling holes on the vertical surface of a cylinder at different angles
as well as different height which increases productivity.
SUMMARY OF THE INVENTION
The present invention is provided with a device for drilling holes
on the vertical surface of a cylinder at different angles and different
height comprises:- an assembly of one Main Index Base Plate and one
Top Index Plate disposed one above the other, and Top Index Plate is
rotatable on one Spigot fixed with Main Index Base Plate; and Main
Index Base Plate is having circular shape and provided with 24 pre-
drilled holes in 1 st Pitch
Circle Diameter (PCD) and 9 pre-drilled holes in 2nd PCD, affixed
with a Spigot at centre; and one Top Index Plate of circular shaped
having four protruded parts disposed at 90° apart, mounted with a
handle at each protruded part and rotatable over the Spigot; and one
Spigot made from a single cylindrical steel piece with one end having
larger diameter and other end having smaller diameter. This is fitted
with bolts on the Main Index Base Plate. Characterised in that the said
device affixed on the table of a Horizontal Drilling and Boring
Machine or a Radial Drilling Machine and wherein the component is
placed vertically on the top of the device affixed with fastenable
means and drilling of holes at different height and different angles are
performed corresponding to the pre-drilled holemark of PCD of the
Main Index Base Plate by rotating the top index plate manually with a
handle.
BRIEF DESCRIPTION OF THE INVENTION WITH
ACCOMPANYING DRAWINGS
Fig-1 shows plan and elevation of component item for drilling.
Fig-2 shows Main Index Base Plate.
Fig-3 shows Top Index Plate.
Fig-4 shows plan and elevation of Spigot
Fig-5 shows a plan view of Main Index Base Plate
placed below the Top Index Plate mounted with a spigot.
Fig-6 shows a schematic view of the new device mounted with two
stud vertically and the device is fixed up in the table of Horizontal
Drilling and Boring Machine.
Fig-7 shows a schematic view of the new device mounted with a
cylindrical component by means of two vertical fastening stud, on
the table of the drilling machine prepared before start drilling.
Fig-8 shows a schematic view of the Top Cover Plate with Lifting
Handle.
Fig-9 shows a photo figure of drilling operation of the component.
Fig-10 shows a photo figure how the operator is rotating the Top
Index Plate with the help of two handle of Top Index Plate.
Fig-11 shows a photo figure how the operator is drilling the
component.
BRIEF DESCRIPTION OF A PREFERRED EMBODIMENT OF
THE INVENTION
The present invention is for a drilling device which is pre-decided
set of holes at different angles and different heights on the vertical
surface of a cylinder. The device comprises a combinating two sets of
plate i.e. Main Index Base Plate and Top Index Plate. These plates are for
making holes corresponding to the required angular position of holes to
be drilled on the vertical surfaces of a cylinder. The Main Index Base
Plate and Top Index Plate would require a
different set of holes on separate pitch circle diameter (PCD) for each set
of holes at different height of any cylinder. In
the present illustration, a set of 24 holes each are required to be drilled
near top and bottom ends of the fibre glass
cylinder (referred component item Fig-1). In addition a set of three, five,
seven or nine holes are required to be drilled at a specified height of the
cylinder. The angular and height position of all holes is relative to each
other and any variation in the position of any hole could cause problems
during assembly.
As shown in Fig-2 the Main Index Base Plate (1) having circular
shape, pre-drilled with 24 holes (2) at a First Pitch Circle Diameter
(PCD) and 9 holes (3) have been drilled at Second Pitch Circle Diameter
(PCD). The PCD of these holes has been deliberately kept separate so
that one
set of holes do not mix with the other set of holes those are being drilled
at a different height.
As shown in Fig-3, the Top Index Plate (4) is a circular shaped
plate having four protruded parts (5a, 5b, 5c, 5d) disposed at 90°c apart
from 1st protruded part to a second protruded part. Each protruded part
comprises of centre hole (6,6) for affixing with the main Index base plate
(1). Two protruded parts (5b & 5d) disposed at 180° apart comprises one
additional hole (7) disposed at the left side of central hole (6) for fixing
on Main Index Base Plate at a different PCD holes. The Top Index Plate
(4) is provided with a central hole (8) for rotation on the Spigot. Further
on the body of the Top Index Plate (4) there are provided with
two holes (9) disposed at 180° apart for mounting two stud for fixation of
component to be drilled. The Top Index Plate is provided with four
handle (10) to facilate rotation on
Main Index Base plate disposed on the protruded parts (5a, 5b, 5c, 5d)
shown in Fig-5.
As shown in Fig 4, one Spigot made from a single cylindrical piece
of a steel rod is having larger diameter at one end (11) and smaller
diameter at the other end (12). Larger diameter side (11) of this Spigot is
provided with 4 holes (13a, 13b, 13c & 13d) disposed at 90°. Using four
bolts, this Spigot is fitted with the Main Index Base Plate (1). Top Index
Base Plate (4) sits on smaller diameter side (12) of the Spigot and Top
Index Plate can be rotated manually around this Spigot through hole (8)
disposed at the centre of the Top Index Base Plate.
Fig 5 shows an assembly of a Main Index Base Plate on which Top
Index Plate (4) are placed through a Spigot (8). Handles (10) are
provided at the protruded part for rotation of top index plate over the
Main Index Base Plate.
Fig 6 shows two studs 'have been mounted on body hole (9) of the
top index plate at 180° aparts for holding the component to be drilled.
Fig 7 shows, the component to be drilled, is placed on the Top
Index Plate (4) and fixed up with nuts (18) at the top of the studs (14) by
placing a Top Clamp Plate (15) on the component. Fig 8 shows a Top
Clamp Plate (15) having two holes (16) at 180° apart though which studs
have passed, the Top Cover Plate provided with Top Cover Handle (17)
for lifting and placing Top Cover Plate in position.
METHOD OF WORKING
After fixing the component on the table of the machine, drilling
starts at lower height of the component matching with the holes (2) of the
Main Index Base Plate in first PCD. On completion of one hole, and by
rotating the Top Index Plate (As shown in Fig 10) to match up the next
hole of the Main Index Base Plate a second hole is drilled in the same
PCD. The first PCD contains 24 holes. All 24 holes are drilled one by
one by rotating the Top Index Plate corresponding to the pre-matched
holes of the Main Index Base Plate in the same PCD.
For drilling holes at a certain height from the bottom of the
component a second PCD holes made in the Main Index Base Plate are
used only by rotating the top index
Plate from one hole to another corresponding to the holes of Main Index
Base Plate (As shown in Fig 9 & 11).
WE CLAIM
1. A device for drilling holes on the vertical surface of a cylinder at
different angles and different height comprises:-
— an assembly of one Main Index Base Plate and one Top Index
Plate disposed one above the other, and Top Index Plate is rotatable
on one spigot mounted on main Index Base Plate;
— one Main Index Base Plate having a circular shape and provided
with 24 pre-drilled holes in 1st Pitch
Circle Diameter and 9 pre-drilled holes in 2nd pitch circle Diameter,
affixed with a Spigot at centre;
— one Top Index Plate of circular shaped having four protruded parts
disposed at 90° apart, mounted with a handle at each protruded part
and rotatable over the spigot;
— one Spigot having first end of a larger diameter and 2nd end of a
smaller diameter mountable with Main Index Base Plate at first
end face wherein the component is placed vertically on the top of
the device affixed with fastenable means and drilling of holes at
different height and different angles are performed corresponding
to the pre-drilled holemark of PCD of the Main Index Base
Plate by rotating the Top Index Plate manually with a handle.
The device as claimed in claim 1 wherein the Main Index Base
Plate and the Top Index Plate are made with steel materials
2. The device as claimed in claim 1 wherein the fastenable stud for
holding the component is also made of steel materials.
The device as claimed in claim 1 wherein the Spigot is placed
upside down on the Main Index Base Plate and fixed up with
fastenable means so that the cylindrical part remain vertical to help
the rotation of the Top Index Plate.
The device for drilling holes on the vertical surface of a cylinder at
different height and different angles as substantially described in the
specification and illustrated herein with accompanying drawing.

The present invention is provided with a device for drilling holes on
the vertical surface of a cylinder at different angles and different height
comprises:- an assembly of one Main Index Base Plate and one Top Index
Plate disposed one above the other, and Top Index Plate is rotatable on one
Spigot fixed with Main Index Base Plate; and Main Index Base Plate is having
circular shape and provided with 24 pre-drilled holes in 1st Pitch Circle
Diameter (PCD) and 9 pre-drilled holes in 2nd PCD, affixed with a Spigot at
centre; and one Top Index Plate of circular shaped having four protruded parts
disposed at 90° apart, mounted with a handle at each protruded part and
rotatable over the Spigot; and one Spigot made from a single cylindrical steel
piece with one end having larger diameter and other end having smaller
diameter. This is fitted with bolts on the Main Index Base Plate. Characterised
in that the said device affixed on the table of a Horizontal Drilling and Boring
Machine or a Radial Drilling Machine and wherein the component is placed
vertically on the top of the device affixed with fastenable means and drilling
of holes at different height and different angles are performed corresponding
to the pre-drilled holemark of PCD of the Main Index Base Plate by rotating
the top index plate manually with a handle.