FORM2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention: AN IMPROVED RACKING SYSTEM FOR USE IN
SWITCHGEARS
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 an improved racking system for use in draw-out breakers. The invention is an integration of the rack with the position indicator cam. This technology is used in the switchgear industry and allied areas.
BACKGROUND OF THE INVENTION
While racking the breaker into a cradle, the position of the breaker needs to be indicated for identifying the different intended positions of the switchgear. This is achieved using a position indicator. The position indicator is actuated using a position indicator cam. This cam is usually a separate part, and is assembled to the rack using various methods. This invention combines the position indicator cam with the rack.
Many inventions have been made in the field using several methods of position indication in switchgears. Some of these are mentioned here.
In US 2010/0230258 by Kim et al a position indicator is installed between a girder, a fixed body, and a main body of the carriage, and an indication number to which the position indication cam is rotatably coupled having a mark symbol to allow the position indication cam to indicate a run and test position of a main body of circuit breaker. This apparatus involves the manufacturing of complex three dimensional cam. Also, the cam being separate part needs to be assembled separately into the system.
US 2009/0255791 A1 by Narayanan et al includes a rotating position indicator having atleast two positions, operably connected to the racking mechanism to rotate the indicator in response to the movement of the racking system. It also

includes a biasing device to bias the rotation of the indicator towards the first position when the racking system is in the disconnected position. This calls for the use of a separate part connected to the main racking device for indicating the position, as against an integrated device serving both the racking action, and leading to the position indication.
OBJECTS OF THE INVENTION
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 an improved racking system for use in draw-out breakers.
Another object of the present invention is to provide simplicity in the racking system.
Another object of the present invention is to provide continuous gearing between the rack and the shaft used for racking the breaker.
These and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.
SUMMARY OF THE INVENTION
According to one of the aspect of the present invention there is provided an improved racking system for use in draw-out breakers, said system comprising :

a shaft means;
at least one pinion means operatively connected with said shaft means ;
a racking means operatively connected with said pinion means and mounted on a racking screw, said racking means comprising :
a position indicator cam means comprises a substantially zig-zag position indicator profile to indicate various positions of said racking means;
a hole means;
a support means;
a position indicator means attached with said support means , said position indicator means comprises :
a position indicator engagement end operatively connected with said position indicator profile ;
a pivot connected with said engagement end;
a display end connected with said pivot such said that display end follows the direction of motion of said racking means adapted to move to and fro and display the change in rack positions ;
wherein said position indicator means engages with said position indicator cam profile and rotates about its pivot;
wherein said position indicator means pivots about the position indicator pivot and corresponding position of the position indicator display end is displayed;
display means operatively connected with said position indicator means to indicate the various positions of the rack means, said display means having plurality of display positions to display the various rack means positions.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig. No. 1 Shows a generic view of the assembly.
Fig. No. 2 Shows a side view of the assembly.
Fig. No. 3 Shows the rear view of the assembly
Fig. No. 4 Shows the side view of the assembly showing the motions of the position indicator and the rack.
Fig. No. 5 Shows an unfolded view of the rack with female slots.
Fig. No. 6 Shows an unfolded view of the rack with gear teeth.
Fig. No. 7 Shows a side view of the rack engaged with the racking screw.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and illustrate the best mode presently contemplated for carrying out the invention. Further functioning of the assembly has been discussed below to describe the way the assembly operates. However, such description should not be considered as any limitation of scope of the present unit. The structure thus conceived is susceptible of numerous modifications and variations, all the details may furthermore be replaced with elements having technical equivalence. In

practice the materials and dimensions may be any according to the requirements, which will still be comprised within its true spirit.
The parts in this invention are listed as follows:
1.Shaft
11. Pinion
2.Rack
21.Hole
22.Gear
221.Female gear slots
222.Bend for geared part
231.Bend at position indicator cam
232.Position Indicator Cam Ingress End
233.Position Indicator Cam Egress End
234.Position Indicator cam Profile
24. Nut
3.Position Indicator
31.Position Indicator pivot
32. Position Indicator display end
33. Position Indicator engagement end 4.Position Indicator Cam Egress End

34. Display position 1
35. Display position 2
36. Display position 3 5.Support
6.Racking screw
The disclosed invention consists of a rack 2 mounted on a racking screw 6. The rack consists of gears 22, and a position indicator cam 23 cut in one of its folds. The Position indicator cam 23 has now been shown in fig 5 and fig 7.
The position indicator 3 engages with the position indicator cam 23 as shown in the figure no.1. The gears of the rack 2 mate with those of the pinion 11 as shown in the figure no. 5. The position indicator 3 rotates pivotably about its pivot placed on the support 5. The position indicator 3 is attached movably to the position display 4 as shown in the figure no.1. The display end 32 of the position indicator seen through the position display 4 displays the position of the rack 2 as shown in figure no. 4 and hence the position of the switchgear.
The front-back motion of the rack 2 leads to the up-down motion of the display end of the position indicator 32 as shown in figure no.4.
The rack 2 consists of gears 22, and a position indicator cam profile 234 as shown in figure no.5 and figure no.6 . The part may be manufactured on a sheetmetal base and bent as required. There are other ways to manufacture the same also.
The gears 22 can also be punched into the rack 2 as female slots, as mentioned in figure no.5. The corresponding assembly for such a part is shown in the figure no.3.

The front-back movement of the rack 2 actuates the motion of the shaft 1 as shown in figure no.4. The position indicator cam 23 traverses the same motion as the rack 2. The position indicator 3 engages with the position indicator cam profile 234 and rotates about its pivot 31 as shown in figure no.1 and figure no.2. The display end 32 of the position indicator displays the change in the racks position as shown in figure no.1 and figure no.4. The ends of the position indicator cam 232,233 represent the Connected & disconnected position of the Circuit Breaker.
A simple lever is applied for the display of the position of the rack and hence position of the Circuit Breaker. The position indicator cam profile 234 is designed according to the requirement of position display 4 for the required motion of the rack 2 as explained by the assembly in figure no. 2 and figure no.4.
Some variations of the rack 2 are mention in this disclosed patent in figure no.5 and figure no.6.
Figure no.6 and figure no.7 show one version of the rack 2 where the gears 22 are cut into the sheet and is further folded 222.
Figure no.5 shows another version of the rack 2 where the female gear slots 221 are punched into the rack 2.
The display mentions plurality of positions 41,42,43 {Here connected, test and disconnected respectively) and the position of the switchgear can be inferred from which position the display end of the position indicator 32 points as shown in figure no.1.
The position indicator 3 is pivoted over a pivot 31 made in the support 5 as shown in figure no.1 and figure no.2. The upward and downward motion of the position indicator display end 32 by the engagement of the position

indicator engagement end 33 is caused by the front and back motion of the rack 2 as shown in figure no.4.
The racking system is actuated by the motion of the racking screw 6, the rack 2 moves to and fro along the racking screw 6 due to the formers constraints. This motion also experienced by the position indicator cam profile 234. Thus, the point of engagement between the position indicator cam profile 234 and the engagement end of the position indicator 33 changes according to the position of the rack 2. The position indicator pivots about the position indicator pivot 31, and a corresponding position of the position indicator display end 32 is achieved.
The position indicator display end 32 position depends on the direction of motion of the rack 2.
The invention uses a two dimensional profile extruded inside the position indicator. This is simpler than three dimensional profiles. The invention leads to lesser number of parts in the racking system. It makes the method of manufacturing the position indicator cam simpler. It leads to a cheaper racking system.

WE CLAIM
1. An improved racking system for use in draw-out breakers, said system comprising :
(a) a shaft means (1);
(b) at least one pinion means (11) operatively connected with said shaft means ;
(c) a racking means (2) operatively connected with said pinion means and mounted on a racking screw (6) said racking means comprising :
a position indicator cam means (23) comprises a substantially zig-zag position indicator profile (234) to indicate various positions of said racking means (2);
a hole means (21);
(d) a support means (5) ;
(e) a position indicator means (3) attached with said support means , said position indicator means comprises :
a positron indicator engagement end (33) operatively connected with said position indicator profile ;
a pivot (31) connected with said engagement end;
a display end (32) connected with said pivot such said that display end follows the direction of motion of said racking means adapted to move to and fro and display the change in rack positions ;

wherein said position indicator means engages with said position indicator cam profile and rotates about its pivot;
wherein said position indicator means pivots about the position indicator pivot and corresponding position of the position indicator display end is displayed;
(f) display means (4) operatively connected with said position indicator means to indicate the various positions of the rack means, said display means having plurality of display positions to display the various rack means positions.
2. System as claimed in claim 1 wherein said racking screw means adapted to actuate the motion of the shaft.
3. System as claimed in claim 1 wherein said position indicator cam means having zig-zag profile comprises a pair ends .
4. System as claimed in claim 5 wherein said pair of ends comprises a top end (232) at its top and a bottom end (233) at its bottom adapted to represent connect and disconnected positions of circuit breaker.
5. System as claimed in claim 1 wherein said position indicator cam uses a two dimensional profile.
6. System as claimed in claim 1 wherein said plurality of display positions comprises connected position , test position and disconnected position.
7. System as claimed in ciaim 1 wherein racking means further comprises plurality of gear means (22).

8. System as claimed in claim 1 wherein racking means further optionally comprises plurality of female gear slots (221) adapted to get punched in the rack.