FORM2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention. -
UNIDIRECTIONAL POWER TRANSMISSION MECHANISM FOR A MCCB
2. Applicant(s)
(a) NAME : LARSEN & TOUBRO LIMITED
(b) NATIONALITY: An Indian Company.
(c) ADDRESS: L & T House, Ballard Estate, Mumbai 400 001,
State of Maharashtra, India
3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed:

TECHNICAL FIELD OF THE INVENTION
The present invention relates to circuit breakers. More particularly, the present invention relates to a unidirectional power transmission mechanism operating on meshing concept for a pneumatic operated MCCB.
BACKGROUND AND THE PRIOR ART
In the current available technologies, overrunning clutch is used to transfer the motion when piston moves in the forward direction and when the piston moves in reverse direction it will not transfer the motion.
In the overrunning clutch, the friction towards the reverse motion is very less which in turn requires only a small amount of force to make it slip. Since the slipping force is very less, it is unable to withstand the shock and also the moment of Inertia force. The moment of inertia force makes it unable to locate the driver in the required position. Also the input shaft which is directly connected to the overrunning clutch should be so precise. If the shaft is on the little lower side, it slips in the forward motion of the piston itself and the total mechanism can fail abruptly.
The disadvantages of the above mentioned prior art is that the manufacturers require more tolerance to speed up the production rate and also to reduce the cost of the product. The accuracy of the product should be high to have the higher product quality which is not in case of the prior art. The product starts to slip in lesser force itself. The positioning accuracy of the driver product is not accurate and also has high impact on the shock or jerk.

Thus there is a need to provide a mechanism in a pneumatic operated MCCB in which the mechanism does not work on friction concept but on the meshing concept.
OBJECTS OF THE INVENTION
A basic object of the present invention is to overcome the disadvantages/drawbacks of the known art.
Another object of the present invention is to provide a mechanism for pneumatic operated MCCB that is suitable to slip in one direction only according to the desired spring force.
Another object of the present invention is to provide a mechanism for pneumatic operated MCCB adapted to work on meshing concept to position the driven component.
Yet another object of the present invention is to provide a mechanism for pneumatic operated MCCB having a spring which is being used to have the desired slipping force and high slipping force adapted to resist against jerk and shock.
These and other advantages of the present invention will become readily apparent from the following detailed description read in conjunction with the accompanying drawings.
SUMMARY OF THE INVENTION
There is provided a unidirectional power transmission mechanism operating on meshing concept for a pneumatic operated MCCB.

According to one embodiment of the present invention, there is provided a unidirectional power transmission mechanism operating on meshing concept for a pneumatic operated MCCB, said mechanism comprising a torsion spring means (4) adapted to resist against jerk and shock; a combined clutch and bearing mechanism transferring torque in one direction and permitting free wheeling rotation in the other direction, said clutch connected to a drive source and a load, said clutch rotating said load in one direction; a shaft (1) having a slot, said slot having a pawl (2) and said torsion spring means (4) placed therein; a cam (3) having a ratchet profile, said profile hold in position using a flange running freely over said shaft (1).
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
In the appended drawings:
FIG.l illustrates front view of the mechanism.
FIG.2 illustrates forward Rotation.
FIG. 3 illustrates reverse Rotation.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The following drawings are illustrative of particular examples for enabling methods of the present invention, are descriptive of some of the methods, and are not intended to limit the scope of the invention. The drawings are not to scale (unless so stated) and are intended for use in conjunction with the explanations in the following detailed description.

Reference is first invited to Fig 1 where a unidirectional power transmission mechanism operating on meshing concept for a pneumatic operated 3VICCB is shown. It shows shaft (1), pawl (2), cam (3) and spring means.
Fig. 2 shows forward rotation of the mechanism in accordance to the present invention.
Fig. 3 shows the direction for reverse rotation in accordance with the present invention.
The invention is thus a unidirectional power transmission mechanism operating on meshing concept for a pneumatic operated MCCB.
DETAILED DESCRIPTION OF THE INVENTION
Accordingly in the present invention, a unidirectional power transmission mechanism operating on meshing concept for a pneumatic operated MCCB is provided.
The full overview of the mechanisms is shown in the fig. 1.and it employ a combination of clutch/bearing mechanism for driving a rotatable CAM (3). These clutch/bearing mechanisms are often called a one-way clutch, and have a function of transferring torque in one direction and permitting free-wheeling rotation in the other direction. In this manner, when a one-way clutch is connected to a drive source such as a two-way motor, the load connected to the clutch is rotated in only one direction.
The mechanism consists of a Cam (3) in which a ratchet profile is being extruded out. It is hold in its position with the help of the flange which can run freely over the main

shaft (1). In the main shaft (1) a slot have has been taken in which the pawl (2) and torsion spring is placed with the help with the help of the pin as shown in the figure. The torsion spring forces the flat end portion of the pawl (2) against the wall of the main shaft (1), which cause it to act as a cam (3) and follower arrangement.
At this time, when the shaft (1) is rotated in the forward direction, the pawl (2) gets engaged with the ratchet profile of the cam (3) and the entire set-up is getting rotated. When the main shaft (1) is rotated in the reverse direction the other side of the pawl (2) gets slipped with the ratchet profile of the cam (3) and the pawl (2) rotates about its own position against the spring force. As soon as the peak point of the ratchet passes away, the pawl (2) tends to go back to its own original position due to the spring force. This happens repeatedly and results no force act against the cam (3) and makes the cam (3) to stand still in its own place and only the main shaft (1) rotates.
Advantages:
• Having high impact towards shock and jerk.
• The slipping force can be varied by varying the spring force.
• Ease of assembly.
Although the embodiments herein are described with various specific embodiments, it will be obvious for a person skilled in the art to practice the embodiments herein with modifications. However, all such modifications are deemed to be within the scope of the claims.
It is also to be understood that the following claims are intended to cover all of the generic and specific features of the embodiments described herein and all the statements of the scope of the embodiments which as a matter of language might be said to fall there between.

WE CLAIM:
1- A unidirectional power transmission mechanism operating on meshing concept for a pneumatic operated MCCB, said mechanism comprising:
a torsion spring means (4) adapted to resist against jerk and shock;
a combined clutch and bearing mechanism transferring torque in one direction and permitting free wheeling rotation in the other direction, said clutch connected to a drive source and a load, said clutch rotating said load in one direction;
a shaft (1) having a slot, said slot having a pawl (2) and said torsion spring means (4) placed therein;
a cam (3) having a ratchet profile, said profile hold in position using a flange running freely over said shaft (1).
2. Mechanism as claimed in claim 1 wherein slipping force is configured to vary by varying the spring force.
3. Mechanism as claimed in claim 1 wherein said clutch is substantially a one way clutch.
4. Mechanism as claimed in claim 1 further comprising a pin to hold said pawl (2) and torsion spring means (4) in said slot.

5. Mechanism as claimed in claim 1 wherein said torsion spring means (4) forcing said pawl (2) against said shaft (1).
6. A unidirectional power transmission mechanism operating on meshing concept for a pneumatic operated MCCI3 as herein described and illustrated with respect to the accompanying drawings.