FIELD OF THE INVENTION
The Present invention generally relates to assembly and dis assembly of
internal or external circlips for Oil Field Equipment (OFE), in particular
mounting or dismounting of large size internal or external heavy duty circlips
on and from oil-field circular components. More particularly, the invention
relates to a system for mounting or dismounting of heavy-duty circlips over
circular components of oil-field equipment.
BACKGROUND OF THE INVENTION
Circlips work as a load bearing shoulder which position and hold mechanical
parts. They provide continuous radial force and secure against high rotational
speeds because they are retained within a groove. The open end of a circlip
creates a spring pressure effect which allows the circlip to fit securely into a
grooved channel on a circular component. The pressure created by the spring
varies, depending on the thickness and diameter of the circlip. In Oil Field
Equipment (OFE) in particular a Valve assembly, a large heavy duty internal
circlip is to be mounted inside the tubing spool. For this purpose, the opening
required for a standard circlip is around 120mm and the outside diameter of
the circlip is 282 mm. There is no standard circlip plier available in the art.
For example, a Standard imported circlip plier is 580mm long and the
maximum opening of the circlip is around 100 mm only. More over, when the
circlip is opened the holding pin of the circlip becomes taper and the circlip is
slipping from the circlip plier. This creates difficulty in assembling the circlip in
the OFE valve. Various circlip pliers like rack type circlip plier, adjustable type
circlip plier etc. does not meet the requirement of this size.
Hence there is a need to develop a special circlip plier to ease the operation
during assembly and dismantling.

OBJECT OF THE INVENTION
It is therefore an object of the invention to propose a system for mounting or
dismounting of heavy-duty circlips over circular components of oil-field
equipment.
SUMMARY OF THE INVENTION
Accordingly there is provided a system for mounting or dismounting of heavy-
duty circlips over circular components of oil-field equipment. The system
comprises a screwing device of left hand and right hand threads which
moves a non rotating cylinder fitted with a pivoting pin which in turn is
housed in a rotating cylinder having helical grooves to rotate the cylinder.
Two radially rotating arms with pins are used to compress or elongate the
circlips according to the nature of the circlip (internal or external). One
radially rotating arm with pin is mounted on the non-rotating central rod and
another radially rotating arm with pin is mounted on the outer rotating
cylinder. This invention can be used for assembling/disassembling of both
internal and external circlips.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The proposed invention will be better understood by the following description
with reference to the accompanying drawings.
Figure 1 Shows the details of a circlip.
Figure 2 Shows the system for assembling / Disassembling of circlips in
larger size oil Field equipment components, according to the invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
As shown in the Figure 2, major components of the plier includes a central
rod (1), a non-rotating cylinder(2), rotating cylinder(6), a nut (4) a housing
(5), and two radially rotating arm.
The central rod (1) retains all other items in position. The non rotating
cylinder (2) slides on the central rod (1), and having an ear with left hand
internal thread for accommodating a Left Hand and Right Hand (LH RH)screw
(3). The handle (11) and the LH RH screw (3) are joined by using a washer
(22) and an allen screw (23). The Housing (5) is mounted on the central rod
(1) by a nut (4) and a plurality of screws (24,12). Rotation of the LH and RH
screw (3) makes the cylinder move axially. RH portion of the screw (3) is
screwed on to the nut (4) and it is mounted on the central rod (1). The
Rotating cylinder (6) is having a helical groove and it is rotating on the
nonrotating cylinder (2). A pivoting pin (15) is assembled between the
nonrotating cylinder (2) and the rotating cylinder (6) at the helical groove
portion. The linear movement to the nonrotating cylinder (2) is activated by
the LH & RH screw (3). This linear movement of the nonrotating cylinder
gives a rotational movement to the rotating cylinder (6) through the pivoting
pin (15) and the helical groove in the rotating cylinder (6). A hexagonal
socket grub screw (Dog point) (14) prevents torsional movement to the
nonrotating cylinder. The handle (11) fitted at the end of the LH & RH screw
(3) by fasteners (22, 23) give rotation to the screw (3) manually. At the end
of the central rod (1), the second arm (9) is attached in the axial groove. This
axial groove on the central rod (1) give freedom to position the second arm
(9) conveniently. A fastener washer (10) and a second screw (21) are used to
fasten the second arm (9). The first Arm (8) is mounted on the rotating
cylinder (6) end by a third screw (19). A first pin (18) and a second pin (20)
are press fitted on the outer end of the first arm (8) and the

second arm (9). A Key (7) is used in between the rotating cylinder (6) and
the first arm (8) to give positive rotation to the first arm (8). The relative
rotation between arms (8, 9) makes the pin closer or wider which will activate
the circlips during assembly. This system can be used for mounting both
internal and external circlips. A first thrust bearing (13) and a second thrust
bearing (16) held by an external circlip (17) are used for smooth rotation of
the rotating cylinder (6).

WE CLAIM :
1. A system for mounting or dismounting of heavy-duty circlips over
circular components of oil-field equipment, comprising :-
- a central rod (1);
- a non-rotating cylinder (2) slidable on the central rod (1), and having
an ear configured with left hand internal thread for accommodating a
L-H screw (3);
- a handle (11) connected via a washer (22) including an allen screw
(23) to said L-H-RH screw (3);
- a housing (5) mounted on said central rod (1) by a nut (4) including a
plurality of screws (12,24);
- a rotating cylinder (6) having a helical groove disposed with a pivoting
pin (15), the rotating cylinder (6) rotating on the non-rotating cylinder
(2) causing a linear movement of the non-rotating cylinder (2) by
activating the LH & RH Screw (3), wherein torsional movement of the
non-rotating cylinder (2) being prevented by a grub screw (14);
- the handle (21) fixed to the distal end of the LH-RH screw (3) by
fasteners (22,23) to rotate the screw (3); and
- two radially rotating arms (8,9) with pin (18 and 20), the relative
rotations between the arms (8,9) adjusting the positioning of the Pin
(18) to compress or widen the circlip corresponding to the circular
component of the OFE.
2. The System as claimed in claim 1, wherein distance of the circlip
holding pins can be adjusted by using serrations at the end of central
rod (1) and the second arm (9).

3. The system as claimed in claim 1, wherein the nut (4) allows
transmitting the torque and supporting other associated components.
4. The system as claimed in claim 1, wherein a fastener washer (10) and
screw (21) are used to fasten the second arm (9), wherein the first
arm (8) mounted at the end of the rotating cylinder (6) by a screw
(19), a first and second pin (18,20) is press fitted on the outer end of
the arms (8,9) wherein a key (7) is used in between the rotating
cylinder (6) and the first arm (8) to give positive rotation to the first
arm (8).
5. The system as claimed in claim 1, comprising a first and a second
thrust bearing (13,16) by external circlip (17) to allow smooth rotation
of the rotating cylinder (6).