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. - AN IMPROVED PHASE BARRIER ASSEMBLY FOR USE IN SWITCH DISCONNECTOR FUSES
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 phase barrier in switch disconnector fuses. More particularly, the invention is concerned about an improved phase barrier assembly for use in switch disconnector fuses.
BACKGROUND OF THE INVENTION
Phase barriers are the components which are assembled beside either side of each phase of the switch disconnector fuse. They are assembled on the front housing of the switch disconnector fuse using the screws and inserts. There are many functions of the phase barriers like prevention of the shorting between any two consequent phases, preventing flash over due to creeping of arc through the air medium, and human safety from accidental touching of the live parts.
The click fit phase barriers are widely used in switchgear products, the mechanism to mount them on the unit lies at the top and bottom of the switchgear unit.
Most of the switch disconnector fuses are used in an enclosure and in a vertically mounted orientation. As a result, the top and bottom of the unit are not accessible to the operator, and thus it is not possible for the operator to dismantle the phase barrier from the unit
US 5,910,757 entitled "Phase barrier for use in a multiphase circuit breaker" discloses a method and apparatus for interrupting the flow of electrical current in a multiphase circuit path between at least one source and at least one load including a circuit breaker having an electro-mechanical assembly and a blade carrier corresponding to each phase of the multiphase circuit path and a phase barrier between each blade

carrier. The blade carriers are interconnected, preferably, with a crossbar wherein, when one or more phases of the circuit path are interrupted, opening one or more of the blade carriers, the crossbar moves all of the blade carriers to open positions. The phase barrier is positioned circumferentially around the crossbar between each blade carrier and includes a thermoplastic material. The electro-mechanical assembly is housed within a circuit breaker enclosure having an insulating base wall and cover wall. The phase barrier has a main body planar surface perpendicular to the blade carriers and extending from the base wall to the cover wall. The phase barrier is preferably manufactured entirely from the thermoplastic material, or in another embodiment, the phase barrier is manufactured of a fiberglass material having a thermoplastic material covering. However, mounting of phase barrier on the switch disconnector fuses was not known from the prior art.
US 5,181,158 entitled "Phase barrier for padmounted switchgear" discloses a multiple-phase electrical distribution apparatus, a number of barrier panels formed of dielectric material are provided for separating electrical transmission components disposed within the apparatus. The barrier panels may be manually placed in and lifted from a working position within the enclosure, and are supported in the working position by a mounting bracket extending horizontally in a direction parallel to the direction in which the components are spaced. The bracket includes a transverse slot disposed between the electrical transmission components and defining a pair of bearing surfaces which grip opposed surfaces of the barrier panel when the lower edge of the panel is inserted in the slot. Also, the barrier panel engages a slot formed in the enclosure above the bracket to stabilize the barrier panel against lateral movement. By this construction, the panels are self supporting and do not require the use of fastening expedients such as threaded fasteners or the like to secure the panels in the working position. However, no such snap fit mounting arrangement of the phase barrier on fuse disconnected switches was known from the prior art.

US 4,791,530 entitled "Insulating barrier system for switchgear" discloses a barrier system is provided for electrical switchgear having an enclosure and one or more access openings. The barrier system comprises a plurality of barriers, each of which is a generally planar member. The barrier system further includes manually operable provisions for releasably securing each barrier in respective predetermined positions, and a guide and support member carried by the enclosure and engaged by the lower edge of the rear portion of each barrier during insertion and also when the barriers are in a predetermined inserted operating position. The guide and support member directs the barrier into the appropriate position when the barrier is within a predetermined range of position with respect to the guide and support member. In a specific embodiment, the manually operable provisions include a fastening device which is retained by the barrier and a cooperating receptacle retained by the enclosure. The fastening device is preferably is a fractional-turn wing-head stud. Additionally, the guide and support member in a specific embodiment includes a tapered guide surface narrowing to a receiving slot for each of the removable barriers. However, no such snap fit mounting arrangement of the phase barrier on fuse disconnected switches was known from the prior art.
The disadvantages of the prior art are such that assembling is done with use of screws and inserts, higher cycle time for assembly of phase barriers , difficulty in recycling and not economical in manufacturing.
Thus, there is a need to overcome the problems of the prior art. Therefore, present inventors have developed an improved phase barrier assembly for use in switch disconnector fuses. It would reduce cycle time for assembly of phase barriers, eliminate screws and economical in manufacturing.
The phase barrier designed in the present invention is different from those used in the prior switchgear industry. The phase barriers of the prior art are mounted on the

switchgear either by screws and inserts or by click fit mechanisms. In the present invention, the screws and inserts are eliminated completely.
OBJECTS OF THE INVENTION
An object of the present invention is to overcome the problems/disadvantages of the prior art.
Another object of the present invention is to provide an improved phase barrier assembly for use in switch disconnector fuses.
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 phase barrier assembly for use in switch disconnector fuses, said assembly comprising
(i) at least of barrier means, said each barrier means comprising:
at least one block means substantially positioned on lower/bottom side of said barrier means;
at least one locking means of barrier means articulated at a predetermined position with said block means having top surface and bottom surface;

at least one arm means operatively connected on the top surface of said locking means , said arm means is having modular profile adapted to provide bending/flexing motion;
at least one handling means positioned on the diametric side of said block means adapted for the pulling and/or pushing of said barrier means;
(ii) at least one housing means having top surface and bottom surface, said housing means comprising:
at least one slot means, said slot means is substantially
positioned on the top surface of said housing means ;
at least one locking means of housing means having side walls
and bottom surface;
such that said housing means is substantially located on the
front of said switch disconnector fuses,
such that on receiving the barrier means into the slot means, the said arm means flexes towards the block means due to the side walls of said locking means of the housing means whereby said top surface of locking means of the barrier means substantially crosses bottom surface of said locking means of the housing means whereby said locking means of the barrier means accommodates into said slot means and releases the flexed arm back to its natural/original position.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Other features as well as the advantages of the invention will be clear from the following description. In the appended drawings:

Fig 1 illustrates an isometric view of a phase barrier.
Fig 2 illustrates an isometric view of the front housing of the switch disconnector fuse.
Fig 3 illustrates a view of the assembly of phase barrier and front housing of the switch disconnector fuse.
Fig 4 illustrates a cross sectional front view of the assembly of phase barrier and front housing of the switch disconnector fuse.
Fig 5 illustrates the exploded view of the phase barrier.
Fig 6 illustrates the exploded view of the front housing of the switch disconnector fuse.
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 assembly. 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.

According to the invention there is provided an improved phase barrier assembly for use in switch disconnector fuses. Figure 1 shows an isometric view of a phase barrier comprises a flexing arm (1) of the snap fit mechanism, locking part of the phase barrier (2), guiding block (3), and handling area to insert the phase barrier (4).
Figure 2 shows an isometric view of the front housing of the switch disconnector fuse comprises locking part of the front housing (5), slots (6) to hold the snap fit mechanism in the front housing.
The improved phase barrier is made up of a click fit mechanism at the bottom, which consists of flexing arm (1), locking portion on the flexing arm (2) and guiding block (3). The entire snap fit mechanism rests on the guiding block as shown in figure 1. The front housing of the switch disconnector fuse consists of locking part (5) and slots to hold the click fit mechanism (6) as shown in figure 2.
The present invention consists of mounting the phase barriers with the help of a snap fit arrangement. The phase barriers constitute of two flexing arms. The front housing contains the locking arrangement for the phase barriers.
To insert the phase barrier, one must hold the phase barrier at the holding area and push the phase barrier into the slots of the front housing. As the phase barrier travels in the slot, the flexing arm (1) flexes toward the guiding block (3) due to the side walls of (5). Once it is sufficiently inserted, the top surface of (2) will cross the bottom surface of (5) and thus result in the release of the flexed arm back to its natural position. This action will lock the phase barrier in the appropriate position, and even if holding from the handling area (4) one tries to pull the phase barriers out from the slots (6) it will not eject out. To pull the phase barrier out of the slots (6), one must press at the front surface of (1) and pull it out of the slots.

The mechanism to mount the phase barriers is designed at the front housing of the switchgear.
The phase barrier would be easily accessible to the operator because the mechanism is designed at the front.
It provides better locking of phase barrier. It is designed keeping in mind instances of misuse which might occur, and ensures the intactness of the phase barriers thereby providing provides sturdiness and durability to the entire switch.
ADVANTAGES OF THE INVENTION
1) Tool free assembly and the screws are eliminated.
2) Reduction in cycle time for assembly of phase barriers.
3) Economical in manufacturing.
4) Due to elimination of metal components, it is a Green design and there is ease of recycling.
5) As phase barriers can be dispatched in an unassembled state the transit damage is limited. The packaging also becomes less bulky and thus overall the cost reduces

WE CLAIM
1. An improved phase barrier assembly for use in switch disconnector fuses, said assembly comprising
(i) at least of barrier means, said each barrier means comprising:
at least one block means substantially positioned on lower/bottom side of said barrier means;
at least one locking means of barrier means articulated at a predetermined position with said bJock means having top surface and bottom surface;
at least one arm means operatively connected on the top surface of said locking means , said arm means is having modular profile adapted to provide bending/flexing motion;
at least one handling means positioned on the diametric side of said block means adapted for the pulling and/or pushing of said barrier means;
(ii) at least one housing means having top surface and bottom surface, said housing means comprising:
at least one slot means, said slot means is substantially positioned on the top surface of said housing means ; at least one locking means of housing means having side walls and bottom surface;

such that said housing means is substantially located on the front of said switch disconnector fuses,
such that on receiving the barrier means into the slot means, the said arm means flexes towards the block means due to the side walls of said locking means of the housing means whereby said top surface of locking means of the barrier means substantially crosses bottom surface of said locking means of the housing means whereby said locking means of the barrier means accommodates into said slot means and releases the flexed arm back to its natural/original position.
2. Assembly as claimed in claim 1 wherein said handling means adapted for the pulling and/or pushing of said barrier means into said housing means.
3. Assembly as claimed in claim 1 wherein said arm means is out of the slots when pressed and pulled on the front surface.
4. An improved phase barrier assembly for use in switch disconnector fuses as herein substantially described and illustrated with the accompanying drawings.