F O R M 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention: TERMINAL SHROUD
ARRANGEMENT IN CHANGEOVER SWITCH
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 changeover switches. More particularly, the invention is concerned about terminal shroud arrangement in changeover switch.
BACKGROUND OF THE INVENTION
In low voltage switchgear, switches are connected to supply through Cables and bus-bar. The end of the cable is terminated on the current carrying terminal by means of lug of appropriate size. Though cable is insulated by means of insulation, however the lug is not insulated. Bare lug is still a live connection which may cause the accidental electric shock to operator while operating the switch. In case of bus-bar connection, the bus-bars are provided with the insulating sleeve. However the sleeves are not up to the point where the bolts are terminated with switch terminals. Hence some parts of the bus-bar are also exposed and prone to cause the accidental shock injury to operator.
US 20070267428 A1 teaches that a casing includes a base, a flip cover pivotably attached to the base, a first member fixed to the flip cover, and a second member fixed to the base. The flip cover is rotatable around an axis of rotation with respect to the base. The first member forms a tip toward the base along a direction perpendicular to the axis of rotation. The second member extends an elongated arm, the elongated arm being crushed by the tip of the first member in an opening process of the flip cover with respect to the base so as to block the flip cover from opening with a rush.
US 4,852,292 document teaches that a cable terminal formed in one piece in resin or plastic material providing a clam shell structure with integral hinge and which closes on a tortuously provided cable in and passages through the structure whereupon closure locks or latches the clam shell cable tautly into the terminal structure and closing a cable gripped bail element on selected rigging. A cap fits over the closed and locked terminal in the form of a terminal shroud or cover.

US 7,227,740 document teaches that a non-conductive bus shroud for a dual circuit breaker system that has a plurality of vertical walls extending generally perpendicular from the top side and including at least one bus member support vertical wall. The dual circuit breaker system includes a housing assembly having a back wall, a first circuit breaker having at least one protruding line terminal, a second circuit breaker having at least one protruding line terminal and at least one bus member extending between the at least one first circuit breaker line terminal and the at least one second circuit breaker line terminal. The bus shroud has a planar member with a top side, a bottom side, a front edge, a back edge, at least one first circuit breaker terminal opening, and a second circuit breaker terminal opening. When the shroud is installed over the circuit breakers, the vertical walls protect and support the bus member.
CN 2485780 (Y) document teaches that a safety installation device for heat overload relay. Terminals of power source and the terminal of electric load are exposed and arranged on foreside and rear of the relay. The device comprises: a base which consists of a hole and a slot used for fixing, a hook-shaped component which is used for being connected with main body of the relay, a support wall which is horizontally stretched and installed out of the base and a safe lid used for covering the terminal of electricity connection and the terminal of electric load connection. Thereby, the safe installation device for the heat overload relay can be easily installed and the accidents of electric stroke can be prevented.
While doing termination, user can remove terminal shroud and may forget to put back the same, which may cause accident. So, there is a need to avoid any accidental contact with live termination part. Human safety is the most important thing in any equipment which is meant for use by human being. Therefore, inventors have developed terminal shroud arrangement in changeover switch in such a way that, without removing terminal shroud user can do termination.
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 terminal shroud arrangement in changeover switch.
Further object of the present invention is to provide reliable locking at 90 0 position.
Yet, another object of the present invention is to provide an easy flip in desired orientation and direction.
SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided a terminal shroud arrangement
in changeover switch, said arrangement comprising:
terminal shroud means;
locking plate means;
wherein said shroud means being provided with an appropriate substantially square space so as
to accommodate said locking plate means;
wherein said locking plate means comprising a substantially square profile being disposed in said
square space of said shroud such that said square profile of the locking plate cooperatively
engages with said shroud means in a manner to define a hinge point such that said terminal
shroud means swivels about said hinge point to attain a steady position at an angle from its
original position; and
wherein said terminal shroud means movement being independent to force application after
attaining dead centre position while swiveling.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 illustrates changeover switch without shrouding protection.
Figure 2 illustrates construction of locking arrangement.

Figure 3 illustrates construction of locking plates with terminal shroud.
Figures 4 and 5 illustrate the view of locking plate when it is inserted into terminal shroud and then to front housing.
Figure 6 illustrates terminal shroud in normal assembly position.
Figures 7 and 8 illustrate the view of terminal shroud when it is flipped for terminating cable lug or link to switch terminals.
Figure 9 illustrates terminal shroud in normal situation.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
According to the invention there is provided terminal shroud arrangement in changeover switch. Figure 1 shows that changeover switch without shrouding protection. Figure 2 shows that construction of locking arrangement. As shown in figure 2, the locking plate means (3) is a plastic component which is inserted into top housing (1). It provides the locking arrangement and hinge point for accessories. Top housing (1) is a plastic component used in the switch in order to house live moving contact and current carrying terminals. Terminal means (2) is copper component which forms fixed contact of switch. Each of the top and bottom switch comprises of 8 terminals.
Figure 3 illustrates construction of locking plates (3) with terminal shroud means (4). Terminal shroud means (4) is a plastic component which is fitted with locking plates (3) and swivels about the centre point of locking plate (3). Terminal shroud means (4) is provided along with the locking plate (3) for the assembly. Terminal shroud means (4) is provided with an appropriate substantially square space so as to accommodate the locking plate means (3). Initially locking plates (3) are inserted into the top-housing (1) as shown in figure 2.

Figures 4 and 5 illustrate the view of locking plate (3) when it is inserted into terminal shroud (4) and then to front housing. The locking plate means (3) comprising a substantially square profile which is disposed in the square space of the terminal shroud means (4). Terminal shroud (4) is fixed into the locking plate (3) in such a way that the square space of terminal shroud matches exactly with the square profile provided into locking plate means (3) as shown in figure 5. The present invention has been tried with locking plate having square profile, however this should not be considered as limiting scope of the invention. Any other profile of the locking plate which matches appropriately with the square profile of the terminal shroud means can replace the square profile of the locking plate and still the invention can be performed in its true spirit.
Terminal shroud means (4) swivels at the hinge point of the locking plate means (3) in such a way that terminal shroud means (4) attains a steady position of exactly 90° from its original position. While swiveling, the terminal shroud means (4) attains a dead centre position, as shown in figure 6, after which the movement of terminal shroud means (4) is independent to force application for movement.
Locking plate means (3) is inserted into the top housing (1) by means of click-fit arrangement. Click-fit arrangement ensures easy insertion and withdrawal of locking plate means (3). Once the locking plate means (3) is inserted in top housing (1), it will have square profile which will accommodate the terminal shroud feature. This locking plate square profile is flexible enough to take care of slight interference fit of terminal shroud means (4) with locking plate means (3).
Square profile of locking plate gives the dead centre effect while flipping the terminal shroud means (4). After the dead centre, the terminal shroud means (4) will independently travel towards its final desired position. This enables terminal shroud means (4) to attend a position which gives easy approach to switch terminals (2) for termination purpose. Figure 6, 7 and 8 illustrate the desired functioning of the terminal shroud means (4).
Withdrawal of terminal shroud means (4) is as easy task as that of insertion in locking plate means (3). Ribs are provided at the extreme left and right corner of terminal shroud (4) to

provide sufficient strength and avoid any sort of crack formation in component while inserting and removing the terminal shroud means (4) from the locking plate means (3).
Terminal shroud means (4) comprises movement arrester as an integral part of the shroud means. This feature limits the movement of terminal shroud means (4) in the direction of terminal means (2). Since the terminals (2) are the current carrying entities, the micro ambient temperature of terminal should not affect the insulation properties of terminal shroud means (4). In order to avoid insulation failure and any thermal shock to operator sufficient clearance has been maintained between the termination means viz. cable lug or bus-bar and the terminal shroud. In figure 6 the assembly of shroud (4) and locking plate means (3) is shown.
Terminal shroud will provide protection against thermal as well as electric shock to the operator thereby insuring the safety as the prime concern in product design.
ADVANTAGES OF THE INVENTION
1) Human safety from electric shock
2) Easy access for termination.
3) Easy to flip in desired orientation and direction.
4) Reliable locking at 90° position.
5) Incorporating the dead centre principle of operation.
The invention has been described in a preferred form only and many variations may be made in the invention which will still be comprised within its spirit. The invention is not limited to the details cited above. 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.

WE CLAIM:
1. A terminal shroud arrangement in changeover switch, said arrangement comprising:
terminal shroud means;
locking plate means;
wherein said shroud means being provided with an appropriate substantially square space
so as to accommodate said locking plate means;
wherein said locking plate means comprising a substantially square profile being
disposed in said square space of said shroud such that said square profile of the locking
plate cooperatively engages with said shroud means in a manner to define a hinge point
such that said terminal shroud means swivels about said hinge point to attain a steady
position at an angle from its original position; and
wherein said terminal shroud means movement being independent to force application
after attaining dead centre position while swiveling.
2. Arrangement as claimed in claim 1 further comprises plurality of rib means operatively engaged with said terminal shroud means.
3. Arrangement as claimed in claim 1 or 2, wherein said ribs means operatively engaged with said terminal shroud means substantially at left corner and /or right corner of said terminal shroud means.
4. Arrangement as claimed in claim 1, wherein said locking plate means being operatively connected to housing by means of click-fit arrangement.
5. Arrangement as claimed in claim 1, wherein said terminal shroud means being made up of plastic material and the like materials.
6. Arrangement as claimed in claim 1, wherein said locking plate means being made up of plastic material and the like materials.

7. Arrangement as claimed in claim 4, wherein said housing being made up of plastic material and the like materials.
8. Arrangement as claimed in claim 1 further comprising movement arrester means adapted to limit movement of said terminal shroud means in a direction of terminal means.
9. Arrangement as claimed in claim 1 wherein said angle of steady position of the terminal shroud means is about 90°.
10. A terminal shroud arrangement in changeover as herein substantially described and illustrated with the accompanying drawings.