FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003 As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
Rod end joint
APPLICANTS
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTORS
SUN1L RAJARAM KULTHE of Technology cell -S3 Division, Crompton Greaves Ltd, Switch gear complex, Nashik 422010, Maharashtra, India, Indian Nationals
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention and the manner in which it is to be performed:

FIELD OF THE INVENTION
The present invention relates to a rod end joint. More specifically, the present invention relates to a rod end joint which comprises an arrestor to prevent sideways rotation of the rod end bearing inside the rod end bracket during torque application.
BACKGROUND OF THE INVENTION
A rod end bearing is a mechanical device used for interconnecting/joining two force transmitting components. A typical rod end bearing comprises a rod and a circular casing. The circular casing includes a ball swivel with an opening through which a boll or other attaching hardware may pass. In a rod end joint between two components, the rod portion of the rod end bearing is configured to be tightened to one component through a lock nut and the ball swivel is configured to be disposed in a rod end bracket and pivoted thereto, where the rod end bracket is fixed to the other component.
In a gas circuit breaker, tripping spring energy is transferred from a load to a mechanism and then mechanism to pole assembly through self aligned rod end joints. In a gas circuit breaker, the load ranges from 5.5 to 6 ton due to which there is a possibility of loosening of lock nuts that tighten the rod portion of rod end bearings with another rods. Therefore, a manual torque of high magnitude such as 7700 kg-cm is required to be applied to tighten the lock nuts.
However, during manual torque application, the rod end bearing of a rod end joint has a tendency to rotate in direction opposite to direction of application of torque. During rotation, the rod end bearing has a tendency to rest on the walls of the rod end bracket and misalign by 15 to 20 degrees with respect to its central axis. The primary reason of misalignment of rod end bearing during torque application is space between the inner

surfaces of the rod end bracket and the rod end bearing, which gives a room to the rod end bearing to incline towards the walls of the rod end bracket during torque application.
The misalignment of rod end bearing with respect to its central axis may result in loosening of the lock pin that joins the rod end bearing to the rod end bracket, thereby damaging the rod end joint between two components.
Conventionally, to avoid the rotation of rod end bearing during torque' application, flat plates are inserted and held manually in space between inner surfaces of rod end bracket and rod end bearing. However, the flat plates have a tendency of slipping out at the time of torque application resulting in damage to the rod end joint.
Therefore, there is a requirement of making a rod end joint which does not get damaged during torque application. The rod end joint should have an effective tool which prevents rotation of the rod end bearing inside the rod end bracket with minimal manual intervention.
OBJECTS OF THE INVENTION
An object of the invention is to make a rod end joint in which sideways rotations of a rod end bearing inside a rod end bracket are prevented with minimal manual intervention,
Another object of the invention is to provide a rod end joint having a tool for preventing the sideways rotation of the rod end bearing inside the rod end bracket during torque application.

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION
According to the invention, there is provided a rod end joint for interconnecting two components transmitting force from one to other. The rod end joint comprises a rod end bearing having a rod, and a ball at one end of the rod and a rod end bracket, the ball being disposed in the rod end bracket and pivoted thereto, the other end of the rod being tightened and locked to one of the component and the rod end bracket being fixed to the other component and an arrestor located in the rod end bracket to prevent sideways rotations of the bail within the rod end bracket.
Preferably, the rod is hollow and is internally threaded and coupled to an externally threaded portion of said other component and locked with a lock nut.
Preferably, the arrestor comprises a base wall, a central opening on the base walk and a pair of parallel U-shaped side members disposed at opposite edges of the base wall, each U-shaped side member having a first limb and a second limb joined together to form a U-shape, wherein each of the first limbs has a flat member extending outwardly therefrom in a direction perpendicular to the plane of the first limb.
Preferably, the base wall is configured to receive a screw at its central opening for tightening the arrestor against the ball, the parallel U-shaped side members are configured to overlap onto circumferential outer edges of the ball, and the flat members are configured to rest onto top surfaces of two opposite walls of the rod end bracket.

According to the invention, there is provided a gas circuit breaker comprising a load spring, a spring powered operating mechanism and a pole assembly interconnected through a plurality of rod end joints, each of the plurality of rod end joints comprising a rod end bearing having a rod, and a ball at one end of the rod and a rod end bracket, the ball being disposed in the rod end bracket and pivoted thereto, the other end of the rod being tightened and locked to one component and the rod end bracket being fixed to another component and an arrestor located in the rod end bracket to prevent sideways rotations of the ball within the rod end bracket.
These and other aspects, features and advantages of the invention will be better understood with reference to the following detailed description, accompanying drawings and appended claims, in which,
Fig. 1 illustrates a gas circuit breaker comprising one or more rod end joints for interconnecting one or more components in accordance with an embodiment of the present invention;
Fig. 2 illustrates an exploded view of a typical rod end joint in accordance with an embodiment of the present invention;
Fig. 3 illustrates an arrestor of the rod end joint in accordance with an embodiment of the present invention;
Fig. 4 illustrates a side view of a rod end joint having an arrestor fixed inside the rod end bracket in accordance with an embodiment of the present invention; and
Fig. 5 illustrates another side view of a rod end joint having an arrestor fixed inside the rod end bracket in accordance with an embodiment of the present invention.
With reference to Fig. 1, a gas circuit breaker 100 is illustrated which comprises a load spring 1, a spring powered operating mechanism 2, a pole assembly 3, rod end joints

4 and 5, rod portions 6 and 7, rods 8 and 9, lock nuts 10 and 11, rod end brackets 12 and 13, and arrestors 14 and 15.
The load spring 1 is coupled to the spring powered operating mechanism 2 through the rod end joint 4, whereas, the operating mechanism 2 is coupled to the pole assembly 3 through the rod end joint 5.
In various embodiments of the present invention, the rod end joint 4 transfers the tripping spring energy of the load spring 1 to the operating mechanism 2, whereas the rod end joint 5 transfers the movement of the operating mechanism 2 to the pole assembly 3. In addition to transfer of force/energy from one component to other, the rod end joints 4 and 5 play a vital role in alignment of load spring 1, spring powered operating mechanism 2. and pole assembly 3.
In an embodiment of the present invention, the rod end joint 4 has a rod portion 6 at one end and a rod end bracket 12 at other end, where the rod portion 6 is coupled to another rod 8 through the lock nut 10 and the rod end bracket 12 is fixed to the load spring 1. Similarly, the rod end joint 5 has a rod portion 7 at one end and a rod end bracket 13 at another end, where the rod portion 7 is coupled to another rod 9 through a lock nut 11. The rod end bracket 13 is a two phase lever slot of the operating mechanism 2. The arrestors 14 and 15 may be inserted inside the rod end brackets 12 and 13 respectively to prevent sideways rotation of the rod end bearings of the rod end joints 4 and 5 when a torque is applied to lock the lock nuts 10 and 11.
In an embodiment of the present invention, the rod end joint 4 may also be referred to as a shock absorber rod end joint as it receives/absorbs shocks pertaining to

release of a load from the load spring 1. Further, the rod end joint 5 may also be referred to as two phase lever joint as it joins the two phase lever slot of the operating mechanism 2 to a turn buckle 9, which may be further connected to rod end of a slide seal shaft of the pole assembly 3.
Fig.2 illustrates an exploded view of a typical rod end joint 4. The rod end joint 4 comprises a lock pin 20, a rod end bearing 22, the rod end bracket 12, and arrestor 14. The rod end bearing 22 comprises a hollow and internally threaded rod portion 6 and a ball 23. The ball 23 is defined by circumferential outer edges 24 and 25, a non-circumferential outer surface 26 and an opening 27 through which a pin 20 or other attaching hardware may pass. The ball 23 may be disposed in the rod end bracket 12 and pivoted thereto using the lock pin 20. Thereafter, the arrestor 14 may be inserted inside the rod end bracket 12 along an axis perpendicular to the longitudinal axes of the lock pin 20 and the rod end bearing 22 and tightened against the non-circumferential outer surface 26 through a screw 28.
With reference to Fig. 3, an arrestor is illustrated. The arrestor 14 comprises a base wall 30, a central opening 31 on the base wall 30, and a pair of parallel U-shaped side members 32 and 33 disposed at opposite edges of the base wall 30. The U-shaped side member 32 comprise a first limb 34 and a second limb 35 joined together to form a U-shape, whereas the U-shaped side member 33 comprise a first limb 36 and a second limb 37. Each of the first limbs 34 and 36 comprise flat members 38 and 39 respectively. which extend outwardly therefrom in a direction perpendicular to the plane of the first limbs 34 and 36. It is evident from the figure that the flat members 38 and 39 extend outwardly from respective first limbs 34 and 36 in opposite directions.

With reference to Figs. 4 and 5, different side views of the rod end joint 4 having an arrestor 14 are illustrated. The arrestor 14 is inserted inside the rod end bracket 12 in such a manner such that the base wall 30 is visible to an operator, the parallel U-shaped side members 32 and 33 overlap onto circumferential outer edges 24 and 25 of the ball 23 and the flat members 38 and 39 rest onto top surfaces of the opposite walls 41 and 42 of the rod end bracket 12.
The flat members 38 and 39 have sufficient width so as to completely rest onto top surfaces of the opposite walls 41 and 42 and restrict the horizontal movement of rod end bearing 22 towards the walls 41 and 42. Since, the rod end bearing 22 is unable to horizontally move towards the walls 41 and 42 during torque application, no sideways rotations of the ball 23 occur inside the rod end bracket 12.
In an embodiment of the present invention, the arrestor 14 is made up of materials like wood, metal, plastic, etc. and is inexpensive, light weight and user friendly.
In an exemplary embodiment of the present invention, when a torque of 7700kg-cm is applied to a 400kv SpSp and 800 kv sp sp Gas Circuit Breaker 100 having rod end joints 4 and 5, there is no horizontal movement of the rod end bearing 22 toward the walls 41 and 42 of the bracket 12 and thus no sideways rotation of the ball 23 occur inside the rod end bracket 12.
Although the invention has been described with reference to a specific embodiment, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiment, as well as alternate embodiments of the invention, will become apparent to persons skilled in the art upon reference to the description of the invention. It is therefore contemplated that such modifications can be made without departing from the scope of the invention as defined in the appended claims

We claim:
1. A rod end joint for interconnecting two components transmitting force from one to other, the rod end joint comprising a rod end bearing having a rod, and a ball at one end of the rod and a rod end bracket, the ball being disposed in the rod end bracket and pivoted thereto, the other end of the rod being tightened and locked to one of the component and the rod end bracket being fixed to the other component and an arrestor located in the rod end bracket to prevent sideways rotations of the ball within the rod end bracket.
2. The rod end joint as claimed in claim 1. wherein the rod is hollow and is internally threaded and coupled to an externally threaded portion of said other component and locked with a lock nut.
3. The rod end joint as claimed in claim 1. wherein the arrestor comprises a base wall, a central opening on the base wall, and a pair of parallel U-shaped side members disposed at opposite edges of the base wall, each U-shaped side member having a first limb and a second limb joined together to form a U-shape. wherein each of the first limbs has a flat member extending outwardly therefrom in a direction perpendicular to the plane of the first limb.
4. The rod end joint as claimed in claim 3, wherein the base wall is configured to receive a screw at its central opening for tightening the arrestor against the ball. the parallel U-shaped side members are configured to overlap onto circumferential outer edges of the ball, and the flat members are configured to rest onto top surfaces of two opposite walls of the rod end bracket.

5. A gas circuit breaker comprising a load spring, a spring powered operating mechanism and a pole assembly interconnected through a plurality of rod end joints, each of the plurality of rod end joints comprising a rod end bearing having a rod, and a ball at one end of the rod and a rod end bracket, the ball being disposed in the rod end bracket and pivoted thereto, the other end of the rod being tightened and locked to one component and the rod end bracket being fixed to another component and an arrestor located in the rod end bracket to prevent sideways rotations of the ball within the rod end bracket.
6. The gas circuit breaker as claimed in claim 5, wherein the arrestor comprises a base wall, a central opening on the base wall, and a pair of parallel U-shaped side members disposed at opposite edges of the base wall, each U-shaped side member having a first limb and a second limb joined together to form a U-shape. wherein each of the first limbs has a flat member extending outwardly therefrom in a direction perpendicular to the plane of the first limb.
7. The gas circuit breaker as claimed in claim 6. wherein the base wall is configured to receive a screw at its central opening for tightening the arrestor against the ball, the parallel U-shaped side members are configured to overlap onto circumferential outer edges of the ball, and the flat members are configured to rest onto top surfaces of two opposite walls of the rod end bracket.