FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention. - A ROTARY ARRANGEMENT FOR
AUTOMATIC TRANSFER SWITCH USED IN CONTACT SYSTEMS
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 :

Field of the invention
The present invention relates to a rotary arrangement for automatic transfer switch used in contact systems. More particularly, the invention relates to a rotary arrangement comprising gear meshing mechanism which would enable reduction in the consumption of energy for switching operation thereby reducing overall torque in the switching system. Further the arrangement of the present invention eliminates spring requirement, pre-compression and initial high torque in the switching system which lead to a simple, highly efficient and compact rotary arrangement.
Background and the prior art
In the conventional systems normally contact pressure is provided by some means of spring arrangement and required pre-compressed force. Due to this substantial high amount of energy is consumed for switching operation thereby increasing the overall torque in the switching system. There is a constant need for energy conservation.
US6124558 describes a rotation activated circuit breaker with a leading auxiliary switch, in which the auxiliary contacts of the auxiliary switch are actuated before the main contacts. An actuator element is provided, which contains a drive pinion that is rotation actuated by an actuating mechanism and a longitudinally movable first gear rack, which engages with the drive pinion and actuates the auxiliary switch. Furthermore, a second gear rack, which lags behind the first gear rack in the closing direction, and an output pinion, assigned to the second gear rack, which is connected to a drive shaft for the breaking mechanism of the circuit breaker, are provided. The tooth pitch of the output pinion and the second gear rack is greater than the tooth pitch of the drive pinion and the first gear rack so that the total rotation angle of the drive pinion and output pinion is the same over the full closing motion of the actuating mechanism. However, the arrangement of this prior art has used springs.
Thus there is a need for a rotary arrangement which would enable reduction in the consumption of energy for switching operation thereby reducing overall torque in the switching system and eliminates spring requirement, pre-compression and initial high

torque in the switching system which would lead to a simple, highly efficient and compact rotary arrangement.
The present inventors has found that an improved rotary arrangement can be achieved by providing a gear mesh mechanism which would eliminate use of springs, pre-compression forces and initial high torque thereby providing a simple, highly efficient and cost effective arrangement for use in automatic transfer switch for switching systems.
Objects of the invention
Accordingly one object of the present invention is to overcome the disadvantages/drawbacks of the prior art.
Another object of the present invention is to provide a rotary arrangement comprising a unique gear meshing mechanism.
Another object of the present invention is to reduce the consumption of energy for switching operation thereby reducing overall torque in the switching system.
Yet another object of the present invention is to provide a rotary arrangement which would eliminate spring requirement, pre-compression and initial high torque in the switching system which lead to a simple, highly efficient and compact rotary arrangement.
Advantages of the invention
1. Low initial torque
2. No springs
3. Zero pre-compression
4. Compactness
5. Higher efficiency
6. Low power consumption

Summary of the invention
According to one aspect of the present invention there is provided an improved rotary arrangement for automatic transfer switch used in contact systems, said arrangement comprising :
housing ;
plurality of input and output terminals being housed in a substantially circumferential manner along said housing whereby said terminals are connected to moving contacts of the switching system thereby establishing current conducting path;
gear mesh mechanism, wherein said gear mesh mechanism comprises driving gear means being located centrally and surrounded by plurality of driven gear means such that said driving gear means is inter-engaged with said driven gear means in a manner that rotational direction of driving gear means is opposite to that of driven gear means;
pair of rack means being inter-engaged to said driven gear means such that rotational movement of said driven gear means actuates linear movement of the rack means such that outward movement of one of the rack means exerts positive force on said moving contact and simultaneous linear inward movement of the other rack means releases pressure from said moving contacts thereby ensuring appropriate distribution of contact pressure.
Brief description of the accompanying drawings
Figure 1 illustrates an input side view of the rotary arrangement of the present invention. Figure 2 illustrates current conducting path in the arrangement of the present invention. Figure 3 illustrates an output side view in the arrangement of the present invention. Figure 4 illustrates an isometric view of the arrangement of the present invention.

Detailed description of the invention
Referring to figures 1,2 and 3, the arrangement of the present invention comprises gear mesh mechanism comprising central gear (1) which is the driver gear adapted for driving pinions (2) which are called driven gear, rack (3A & 3B), magnetic cladding 1 (4A, 4B), insulation sheet (5), moving contact (6A, 6B), input terminal (7A, 7B), stopper (8), housing (9), output terminal (10) and magnetic cladding 2 (11 A, 11B).
The terminals (7A, 7B and 10) are housed in the housing (9) along the circumference. Quadrant 1 as shown in figure 1 describes the operation of one pole and operations of the other three poles are identical as described hereinafter. As shown in figure 1, there are two input terminals (7A, 7B) and one output terminal (10) for each pole. These two input terminals (7A, 7B) are for two input sources (Main supply and auxiliary supply). Automatic Transfer Switch switches between main and auxiliary supply. This input and output terminals (7A, 7B, 10) are connected by moving contact (6A, 6B) to complete the current conducting path as shown in figure 2. Magnetic cladding (4A, 4B, 11 A, 11B) provides path for magnetic flux. A physical barrier means is provided between the moving contacts (6A, 6B) and the terminal (7A, 7B( 10) to cut off the power supply. The physical barrier means comprises an insulation sheet (5) which is interposed between the moving contacts (6A, 6B) and the terminal to move the moving contact away from the terminals to separate the moving contact from the terminals to cut off power supply.
Following are the steps involved in the operation of the switch for one pole. The same applies for the other three poles for a Quadra-pole switching system:
Stept: Central gear (1) rotates with the shaft which is rotated by an actuator (like rotary solenoid) for e.g. if central gear is rotated in anti-clockwise direction.
Step2: Central gear drives the pinion (2). Here the pinion rotates in clockwise direction.
Step3: Each Pinion (2) operates two Racks (3A, 3B). Arrangement of the rack and pinion is such that when one rack moves inwards (for e.g. 3A) i.e. towards the centre, the corresponding racks moves outwards (for e.g. 3B) i.e. away from the center.

Step4: The outward movement of the rack (for e.g. 3B) will exert positive force on the moving contact (6B) thereby ensuring proper contact pressure.
Step5: Simultaneously adjacent rack (for e.g. 3A) releases the contact pressure from the moving contact (6A).
Step6: While the rack (3A) is moving inwards, the insulation sheet interrupts between the moving contact (6A) and terminal (7A) thereby breaking the current. Here the insulation sheet (5) rotates in anti-clockwise direction.
Step7: Simultaneously the rack (3B) is moving outwards, the insulation sheet (5) will open between the moving contact (6B) and terminal (7B) thereby making the current.
Step8: The rotation of the insulation sheet (5) is dependent on rotation of central gear
(1).
Step9: Stopper (8) restricts the movement of the moving contact (6A, 6B) and Magnetic Cladding (4A, 4B).
The structure thus conceived is adaptable to numerous modifications or variations. In practice the materials and dimensions may be dependant upon specific requirements and that will be comprised within its true spirit.

WE CLAIM
1. An improved rotary arrangement for automatic transfer switch used in contact
systems, said arrangement comprising:
housing;
plurality of input and output terminals being housed in a substantially circumferential manner along said housing whereby said terminals are connected to moving contacts of the switching system thereby establishing current conducting path;
gear mesh mechanism, wherein said gear mesh mechanism comprises driving gear means being located centrally and surrounded by plurality of driven gear means such that said driving gear means is inter-engaged with said driven gear means in a manner that rotational direction of driving gear means is opposite to that of driven gear means;
pair of rack means being inter-engaged to said driven gear means such that rotational movement of said driven gear means actuates linear movement of the rack means such that outward movement of one of the rack means exerts positive force on said moving contact and simultaneous linear inward movement of the other rack means releases pressure from said moving contacts thereby ensuring appropriate distribution of contact pressure.
2. Arrangement as claimed in claim 1 wherein said driven gear means is pinion.
3. Arrangement as claimed in claim 1 wherein said driving gear means is adapted to rotate in anti-clockwise direction, optionally in clockwise direction.
4. Arrangement as claimed in claims 1 and 2 wherein said driven gear means is adapted to rotate in clockwise direction, optionally in anti-clockwise direction.

5. Arrangement as claimed in any of the preceding claims further comprises plurality physical barrier means.
6. Arrangement as claimed in claim 5 wherein said physical barrier means is insulation sheet located inbetween said moving contacts and said terminals.
7. Arrangement as claimed in claim 6 wherein said insulation sheet is adapted to be rotated by means of the driving gear.
8. Arrangement as claimed in any of the preceding claims further comprises stopper means adapted to restrict the movement of said moving contacts to only linear movement.
9. An improved rotary arrangement for automatic transfer switch used in contact systems as herein substantially described and illustrated with the accompanying drawings.