Field of Invention
This invention relates to development of a turn table used for checking the overall
undulation or flatness of the seat of various sizes or shapes after surface preparation of
weapon of sensor seats. More particularly, the present invention relates to a requirement of
levelling and alignment checks of the seat during the installation of various weapon and
sensors on the naval ships.
Background Art
Indian Naval ships and Coast Guard Ships are generally built by GRSE Ltd. and
various weapon and sensors are being installed on the ship by weapon shop. Various weapon
and sensors are generally fitted with the ship structure by welding.Every weapons and
sensor seat should be erected accurately maintaining proper levelling and alignment which
is a very very important activity regarding weapon installation.In this respect weapon shop
designed and fabricated a versatile turntable. This turntable used for alignment of various
Weapon & Sensor seats of the Warship which is generally built in a floating condition. This
is typically used for undertaking controlled welding of weapon & major seats. This has
resulted not only in achieving high degree of accuracy in levelling in horizontal plane in
floating ship but also reduce the time taken for alignment by 50%.
This versatile turntable can be used for various sizes of weapon seats varying from
700mm diameter to 3 meter diameter seat and also for square or rectangular seats.This
turntable also used for checking the overall undulation or flatness of the seat of various
sizes or shapes after surface preparation of weapon of sensor seats. Ultimately we can
ensure to complete the levelling and alignment job in a time bound manner.

Object of Invention
The primary object of the present invention is to manifest the arrangement and
procedure while erection and surface preparation of different weapon and sensor seats of
various shape and size on board ship.
Summary of Invention
The innovation relates to a development of a versatile turn table used during seat
erection of various weapon and sensor seat on warship in floating condition.
(a) To create a reference plan at site which is act as a MRP of the ship.
(b) Used for checking the overall undulation or flatness of the seat of various
sizes or shapes after surface preparation of weapon of sensor seats.
(c) Used for checking the overall undulation during controlled welding and finalize
the welding sequence.
(d) To provide a economical, safe and quality solution for erection of weapon and
sensor seats.
Therefore such as herein described that is disclosed a turntable for checking undulation
of a seat rotatably supported on a turn table structure plate, a lower segment plate and an
upper segment plate with a top plane connected win a central shaft, a rotary drive means for
rotating the turntable including bearings at lower and upper half and a sleeve bearing

configured for rotating said plates along a central axis connected through a shaft, a clamp
for holding the straight edge of the said seat on said top plane, a Jacking arrangement for
levelling the said segment plates, and plurality of engraved marking over said top plane for
detecting the rotation angle of the turntable mounted for levelling on the top plan of said
upper segment plate.
Brief Description with the Accompanying Figures
Fig. 1(a), (b), (c) and (d) illustrates the typical configuration of versatile turn
table in accordane with the present invention;
Fig. 2 illustrates the application of turn table with straight edge in accordane with
the present invention.
Detailed Description
The invention as shown in figures 1 and 2 is turn table used for checking the overall
undulation or flatness of the seat of various sizes or shapes after surface preparation of
weapon of sensor seats. The levelling of the top plane can be adjusted by jacking arrangement
and it is mounted on a structure with three legs which can be secured on the ship structure
by welding.The turn table has engraved mark at different angle throughout 360p to check
the levelling at different angle.on top of the table there is a clamp arrangement for securing
the straight edge of different sizes, the top plane of the table is secured with the structure by
bush and shaft arrangement to facilitate smooth rotation in both both direction throughout
360p .Centre line of the turn table is engraved on table structure to align the table with seat
centre line.The turn table is designed in such a way the levelling of the top plane can't be

disturbed or changed once it is aligned to the MRP and while rotating it's levelling will not be
changed. The flatness of the top surface of the turn table is double delta finish which is
checked periodically for the accuracy of the turn table inhouse by putting it on the surface
plate and taking reading by dial gauge.
This versatile turntable can be used for various sizes of weapon seats varying from
700mm diameter to 3 meter diameter seat and also for square or rectangular seats.This
turntable used for checking the overall undulation or flatness of the seat of various sizes or
shapes after surface preparation of weapon of sensor seats. Ultimately one can ensure to
complete the levelling and alignment job in a time bound manner. With this versatile turn
table one can check the undulation or flatness of the seat of various sizes or shapes resulting
most economical procedure. The disclosed turn table is very useful for erection and surface
preparation of different weapon and sensor seats fitted on the ship in floating condition.
Table 1 (List of Items)
Item No. Name of Item
1 Top plane
2 Clamp for holding straight edge
3 Jacking arrangement for levelling
4 Engraved marking
5 Bearing (lower half)
6 Bearing (upper half)
7 Structure of turn table
8 Sleeve bearing
9 Shaft
10 Upper segment
11 Lower segment

Advantages & Uses of the Invention
• After creating a reference plan on the turn table at site we need not to check the
levelling of the seat repeatedly with MRP (Master Referance Plane), saves lot of time
and manpower.
• With this versatile turn table we can check the undulation or flatness of the seat of
various sizes or shapes resulting most economical procedure.
• This turn table can be used for surface preparation by hand grinding of different seat
of various shape and size.
• This turn table can be used for controlled welding of different seat of various shape
and size.
Although the foregoing description of the present invention has been shown and
described with reference to particular embodiments and applications thereof, it has been
presented for purposes of illustration and description and is not intended to be exhaustive
or to limit the invention to the particular embodiments and applications disclosed. It will be
apparent to those having ordinary skill in the art that a number of changes, modifications,
variations, or alterations to the invention as described herein may be made in complete
specification, none of which depart from the spirit or scope of the present when interpreted
in accordance with the breadth to which they are fairly, legally, and equitably entitled.

We claim :
1. A turn table for checking undulation of a seat rotatably supported on a turn
table structure plate, a lower segment plate and an upper segment plate with a top plane
connected wih a central shaft, a rotary drive means for rotating the turntable including
bearings at lower and upper half and a sleeve bearing configured for rotating said plates
along a central axis connected through a shaft, a clamp for holding the straight edge of the
said seat on said top plane, a Jacking arrangement for levelling the said segment plates, and
plurality of engraved marking over said top plane for detecting the rotation angle of the
turntable mounted for levelling on the top plan of said upper segment plate.
2. The turn table as claimed in Claim 1, wherein said turn table is configured
for checking the overall undulation or flatness of the seat of various sizes or shapes after
surface preparation of weapon of sensor seats.
3. The turn table as claimed in Claim 1, wherein the levelling of the top plane is
adjusted by jacking arrangement and it is mounted on a structure with three legs which can
be secured on the ship structure by welding.
4. The turn table as claimed in Claim 1, wherein said engraved mark is present
at different angle throughout 360p in order to check the levelling at different angle.
5. The turn table as claimed in Claim 1, wherein the said clamp arrangement
configured for securing the straight edge of different sizes onthe top plane of the said table
and is secured with the structure by bush and shaft arrangement to facilitate smooth
rotation in both both direction throughout 360p.

6. The turn table as claimed in Claim 1, wherein the said centre line of the turn
table is engraved on table structure in order to align the table with seat centre line.
7. The turn table as claimed in Claim 1, wherein the said table is configured in
such a way that the levelling of the top plane can't be disturbed or changed once it is aligned
to the MRP and while rotating it's levelling will not be changed.
8. The turn table as claimed in Claim 1, wherein the flatness of the top plane of
the turn table is double delta finish which is checked periodically for the accuracy of the
turn table inhouse by putting it on the surface plate and taking reading by dial gauge.
9. The turn table as claimed in Claim 1, wherein the said table is configured for
various sizes of weapon seats varying from 700mm diameter to 3 meter diameter seat and
also for square or rectangular seats.
10. The turn table as claimed in Claim 1, wherein table is configured for erection
and surface preparation of different weapon and sensor seats fitted on the ship in floating
condition.