FIELD OF THE INVENTION
The invention relates to a device of Independent Rotary drive system (IRD) for
sky top model mast and substructure to reduce wear and tear of draw works.
BACLKGROUND OF THE INVENTION
In oil rigging operation, generally the draw works power is used for supporting
the drill pipe and also giving the torques to the drilling stem is provided by a
rotary table that gets drives from draw works. This has a disadvantage as the
draw works has to run all through the drilling operation there by the life of the
bearing, shafts and other supporting equipment gets drastically reduced.
To overcome this practical operational hazard; an independent rotary drive (IRD)
system is being developed and installed in branham type of mast and
substructure.
This IRD system can not be installed in sky top type of mast and substructure
due to limitation of working space between welll center and the mast.
Hence, a device of an Independent Rotary Drive system for sky top type of mast
and substructure was developed to address the above problem to reduce wear
and tear of draw works.

OBJECTS OF THE INVENTION
It is therefore, an object of the present invention to propose a device of
inpendent rotary drive system for sky top model mast and substructure which
eliminates the disadvantages of prior Art.
Another object of the present invention is to propose a device of Independent
Rotary Drive System for sky top model mast and substructure which constitutes
an integrated assemble of independent rotary Drive System to generate torque
to drill stem.
A further object of the present invention is to propose a device of independent
rotary drive system for sky top model mask and substructure which increased
the life of the bearing, shafts and other supporting equipments.
SUMMARY OF THE INVENTION
In order to install IRD system in skytop type mast and substructure, the
substructure configure was redesigned keeping the mast identical to
accommodate the single skid IRD system. The whole structure was analysed on
STAAD S/W and integrity of mast and substructure was checked. A single skid
independent Rotary drive (Single speed. Horizontal split gearbox) was developed
to suit this redesigned skytop model Mast and substructure. It consist of a Motor
coupled with a single speed reduction gear box which is connected to rotary
through chain coupling. All the three are mounted on a single skid thereby
avoiding dismantling and assembly of different components during every rig
move.

BRIEF DESCRIPTION OF THE DRAWING
Fig -1- shows a schematic diagram of a device including the drill floor plan of the
redesigned drilling rig for drilling loads and to accommodate IRD unit.
Fig -2- shows a schematic diagram of device including the single skid
independent rotary system for sky top type mast and substructure.
Fig -3- shows a schematic diagram of drill floor of original substructure of skytop
type Rig (prior Art).
DETAILS DESCRIPTION OF THE PREFERRED ENBODIMENT OF THE
INVENTION
As shown in Fig- 1 A drill floor plan of redesigned drill rig for supporting the
drilling machinery and drilling loads and to accommodate IRD unit comprising a
set back speader (1), it transfers set back load of 250 Ton to the ground through
the case set back columns. In order to accommodate the IRD (2) unit, the front beam (A) of set back was redesigned considering of the load capacity; also
provides a front floor support Box (3) which is a critical component of
substructure which transfers set back load and loads from A frame to the ground
through columns. The inside beam (B) was connected to strong back beam (6) in
the prior art. For installation of IRD unit, supporting beam (B) and supporting
sheave (C) were modified to have more space to accommodate the IRD unit.
The assembly also provides a Rotary Beam (4) which accommodates a Rotary
table, being a rugged machine to rotate drill stem and supports its weight. This
also transfers horizontal loads of set back to strong back beam (6). This was also
redesigned to accommodate IRD unit.

A Rotary floor spreader (5) (off driller side) which gives support to rotary floor
and also takes IRD unit load by proper setting of position.
The assembly also includes a strong back beam (6) which is main component of
substructure which transfers casing loads, draw work's load and lateral loads of
set back and Draw works. Present invention modified this beam to suit
redesigned rotary beam, front floor support box and rotary spreader.
As shown in Fig - 2, the assembly comprising a IRD skid (7) which is a rugged
structure to support Rotary table (8) and IRD component like gearbox (9) motor
(10) clutch cum brake (11) and flexible coupling (12). The IRD components
comprises a motor (10) which is an independent motor (10) which gives the
drilling torque to rotary through gearbox (9). The gear box (9) having a single
speed reduction gear which increases to drilling torque by reducing the drilling
speed. A flexible coupling (12) transfer the drives from motor (10) to gear box
(9). A chain coupling (13) is attached to the gear box (9), transfer the drive from
gear box (9) to rotary table ( ). In case of failure of IRD unit, it transfer drive
drawn from draw works to rotary table through an emergency sprocket. An Air
flex clutch (11) is also attached in conjunction of motor and motor coupling
adapter. This air flex clutch works as an air operated brake to stop IRD system.

WE CLAIM
1. A device of Independent Rotary Drive (IRD) system for skytop model mast and
substructure, the rotary drive system comprising:-
- at least one independent motor (10) which gives the drilling torque to rotary
through a single speed reduction gear (9) which increases drilling torque by
reducing the drilling speed;
- at least one flexible coupling (12) attached in junction of motor coupling
adapter and gear box input shaft which transfer the drive from motor to gear
box;
- at least one chain couplings (13) attached in junction of gearbox input shaft
and rotary pinion shaft which transfer the drive from gear box to rotary
table;
- at least one rotary table (8) disposed on the rugged structure and
- at least one rotary brake (12) to control the rotation of table (8).
2. An improved skytop model mast and the substructure including the device of
Independent Rotary Drive (IRD) system, comprising:-
- at least on set back spreader (1) which transfers set back load to the ground
through casing set back columns and accommodates IRD system (2),
- at least one front floor support box which transfer set back load and loads
from A frame to the ground through columns and also connected with bearn
(B) and support sheave (C);

a plurality of rotary beam (4) which accommodates rotary table (a rugged
machine to rotate drill stem and supports its weight);
at least one rotary floor spreader (5) which gives support to rotary floor and
also takes IRD unit (2) load and
at least one strong back beam (6) which transfer casing load, draw work's
load and lateral loads of set back and draw works.

ABSTRACT

A DEVICE OF INDEPENDENT ROTARY DRIVE (IRD) SYSTEM FOR SKY
TOP MODEL MAST AND SUBSTRUCTURE
The invention relates to device of Independent Rotary Drive system (IRD) for sky
top model mast and substructure to reduce wear and tear of the drawworks.
In sky top model substructure, due to space limitation IRD can not be
accommodated. Therefore to accommodate IRD, the shy top substructure was
modified for components front floor support box (3) of fig 1, rotating beam (4) of
fig 1 as wall as new compact gear box was designated.