FORM 2
The Patents Act 1970 (39 of 1970)
&
The Patent Rules 2003
COMPLETE SPECIFICATION
(See Section 10 and rule 13)


TITLE OF THE INVENTION:
SHROUD ASSEMBLY FOR SWITCHBOARD
APPLICANT: LARSEN & TOUBRO LIMITED
L&T House, Ballard Estate, P.O. Box No. 278,
Mumbai-400 001, Maharashtra.
INDIA.

PREAMBLE OF THE DESCRIPTION:
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED


A) TECHNICAL FIELD
[0001] The present invention generally relates to switch boards and particularly to bus bar joints in switchboard. The present invention more particularly relates to mechanism for insulating joints in bus bars at a switch board.
B) BACKGROUND OF THE INVENTION
[0002] Bus bars are conductors usually made of copper or aluminum for interconnection in power-handling devices. The bus bars usually serve as a common connection between several circuits. Typically the bus bars are flat strips or hollow tubes to increase the ratio of surface area to cross-sectional area to improve the heat dissipation. The thickness of the bus bar assemblies comprising plurality of bus bars is increased when the current rating of the switchgear device is increased. In switch board, the bus bar carries main current and the joints on the bus are made to tap off power.
[0003] The bus bars are connected to each other and to an electrical apparatus using bolt or clamp mechanisms. Pluralities of joints are used to ensure proper length and configuration of bus bars. The joints act as take-off points connected to an end-device. The joint assembly is to be insulated to prevent inadvertent accidents and to ensure safety of the operating and maintenance personnel,
[0004] The joints should be accessible for maintenance which involves the tightening and replacement of the joint members such as bolts. The insulation of the joints is to
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be removed to provide access to the joints. The installation and the removal of the insulating components require heavy hardware equipments. Further the removal and installation of the insulating components needs obstruction free access to avoid the damages to the components.
[0005] The joints in the bus bars are difficult to be insulated with the conventional sleeves. Hence a box shaped component such as a shroud is used to cover the joints. The shroud is provided with more than one component to assemble it over the joints. As there are varieties of bus bar with different cross sections, the shrouds with various sizes are to be manufactured to meet the demand.
[0006] Currently the shrouds are made of plastic components and assembled on.the joint. At least two components are required to enclose and insulate the joints completely. As these two parts are to be assembled in the bus bar zone, which is a very compact and inaccessible area, the job becomes tedious and time consuming. Also for performing the service and maintenance of the joints, these parts are to be separated again and which may be difficult due to the limitations in access. The component may get damaged and may not be reassembled again during the maintenance and reinstallation process.
[0007] In some other cases a plastic paint/insulation is used. The plastic paint sprayed in liquid form is solidified to form an insulation layer. In another case a PVC shroud is used. It is elastic and it is pre-moulded with the shape of joint. This moulded component needs hardware and costly equipment for fastening. Such joints are difficult for maintenance too. In some insulation methods PVC is pre-molded
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according to the shape of joint. Each joint shape requires a different pre-mold which is expensive and may not be desirable.
[0008] Hence there is a need to provide a single shroud assembly provided integrally with a fastening means for fixing on the bus bars to insulate the joints. Further, there is a need to provide a single shroud assembly which can be altered easily corresponding to any shape and size of the joints in the bus bar assembly.
[0009] The abovementioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and studying the following specification.
C) OBJECT OF THE INVENTION
[0010] The primary object of the present invention is to provide a single shroud assembly with an integrated/preassembled fastener to insulate a bus bar joint on the switchboard.
[0011] Another object of the present invention is to provide a single shroud assembly with a facility for changing the size and shape corresponding to the size and shape of the bus bar assembly.
[0012] These and other objects and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.
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D) SUMMARY OF THE INVENTION
[0013] The various embodiments of the present invention provide a shroud assembly with a snap fit mechanism for mounting over the bus bars in a bus bar assembly to cover and insulate the bus bar joints. According to one embodiment of the present invention, the shroud has two vertical side plates connected at the top by a top plate. The two vertical side plates are provided with pattern of slots to adjust the size of the shroud corresponding to the size of the bus bar assembly. The slots are formed along the horizontal and the vertical directions on the side plates. Pluralities of snap fit mechanisms are fastened to the top plate to mount and fix the shroud assembly firmly with the bus bar assembly. Each snap fit mechanism is molded in inverted u-shape and the edges are bent inwardly or outwardly to hold the bus bars tightly. The snap fit mechanism is provided with resilient edges to hold the bus bars firmly, when the shroud is mounted on the bus bar assembly. The snap fit mechanism is provided with two protrusions at the top so that the two protrusions are inserted into the holes provided on the top plate of the shroud to fix the snap fit mechanism with the shroud.
[0014] According to another embodiment of the present invention, the snap fit mechanism is provided with a front side plate formed with two pieces which are separated from each other.
[0015] Thus the various embodiments of the present invention provide a single shroud assembly with integrated snap fit mechanism. As the two components, the snap fit mechanism and the shroud are assembled together to form a single assembly thereby reducing the assembly time and manpower used in the assembly process. The unique
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shape of the snap fit mechanism enables to mount the shroud assembly on the bus bar easily without using any kind of fastener or hardware means. The snap fit mechanism is directly fixed on the bus bars so that the shroud is not moved from its place and is replaced easily and quickly. The snap fit mechanism also eliminates the need for any kind of fastening to the bus bar. Since the shroud can be cut on the slotted lines, the size of the shroud may be adjusted easily to suit the bus bar of any shape and size. This has reduced the need for the variety of shrouds required for the bus bars and the joints of different sizes. The shroud can be cut vertically as well as horizontally. The slots also help to keep air flow around the joint to improve the heat dissipation as the joint is one of the hot points in the bus system. The snap fit mechanism is pre fabricated and assembled to the shroud easily thereby reducing the manufacturing time of the shroud assembly. The shape of the shroud helps to insulate the joint from all directions.
[0016] These and other objects and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.
E) BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiment and the accompanying drawings in which:
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[0018] FIG.l illustrates a top perspective view of the shroud assembly according to one embodiment of the present invention.
[0019] FIG. 2 illustrates a top perspective view of a snap-fit mechanism used in the shroud assembly according to one embodiment of the present invention.
[0020] FIG. 3 illustrates a top perspective view of a snap-fit mechanism used in the shroud assembly according to one embodiment of the present invention.
[0021] FIG. 4 illustrates a front side view of a vertical side plate in the shroud assembly according to one embodiment of the present invention.
[0022] FIG. 5 illustrates a side view of the shroud assembly mounted on the bus bar assembly according to one embodiment of the present invention.
[0023] FIG. 6 illustrates the front view of the shroud assembly according to one embodiment of the present invention, with the shroud assembly mounted on the bus bar assembly.
[0024] Although specific features of the present invention are shown in some drawings and not in others. This is done for convenience only as each feature may be combined with any or all of the other features in accordance with the present invention.
F) DETAILED DESCRIPTION OF THE INVENTION
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[0025] In the following detailed description, a reference is made to the accompanying drawings that form a part hereof, and in which the specific embodiments that may be practiced is shown by way of illustration. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments with and without modifications. It is to be understood that the logical, mechanical and other changes may be made without departing from the scope of the embodiments. The following detailed description is therefore not to be taken in a limiting sense,
[0026] The various embodiments of the present invention provide a shroud assembly with a pre assembled snap fit mechanism for mounting over the bus bars in a bus bar assembly to cover and to insulate the bus bar joints.
[0027] According to one embodiment of the present invention, the shroud assembly has a shroud pre assembled with a snap fit mechanism. The shroud has two vertical side plates that are connected at the top by a top plate. The shroud is a single body made of polycarbonate sheet. The sheet is cut and then bent to get the box shape. The two side plates are provided with a pattern of slots to adjust the size of the shroud corresponding to the size of the bus bar assembly. The slots are arranged along the vertical and horizontal directions on the side plates so that the side plates are cut horizontally and vertically corresponding to the size of the bus bar assembly to adjust the size of the shroud with respect to the size of the bus bar assembly. The top plate is provided with a pair holes to receive and secure a snap fit mechanism. The shroud assembly is formed in the inverted U-shape.
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[0028] A snap fit mechanism is fastened to the top plate to mount and fix the shroud assembly firmly with the bus bar assembly. The snap fit mechanism is a molded component. According to one embodiment the snap fit mechanism is made with a plastic component. The snap fit mechanism has two protrusions at the top. The edges at the front side and at the back side of the snap fit mechanism are bent inwardly or outwardly to hold the bus bars tightly. The snap fit mechanism is provided with resilient edges to hold the bus bars firmly, when the shroud is mounted on the bus bar assembly.
[0029] Each snap fit mechanism is molded in inverted u-shape and the edges are bent inwardly or outwardly to hold the bus bars tightly. The snap fit mechanism is provided with resilient edges to hold the bus bars firmly, when the shroud is mounted on the bus bar assembly. The snap fit mechanism is provided with two protrusions at the top with click fit design so that the two protrusions are inserted into the holes provided on the top plate of the shroud to fix the snap fit mechanism with the shroud. No hardware is used to fix the snap fit mechanism with the shroud.
[0030] According to another embodiment of the present invention, the snap fit mechanism is provided with a front side plate which is formed with two pieces that are separated from each other.
[0031 ] Thus the various embodiments of the present invention provide a single shroud assembly with integrated snap fit mechanism. As the two components, the snap fit mechanism and the shroud, are assembled together to form a single assembly thereby reducing the assembly time and the manpower used in the assembly process. The
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unique shape of the snap fit mechanism enables to mount the shroud assembly on the bus bar easily without using any kind of fastener or hardware means. The snap fit mechanism is directly fixed on the bus bars so that the shroud is not moved from its place and is replaced easily and quickly. The snap fit mechanism also eliminates the need for any kind of fastening to the bus bar. The snap fit mechanism is pre fabricated and assembled to the shroud easily thereby reducing the manufacturing time of the shroud assembly.
[0032] The shroud can be cut vertically as well as horizontally along the slotted lines. Since the shroud can be cut on the slotted lines, the size of the shroud may be adjusted easily to suit the bus bar of any shape and size. This has reduced the need for the variety of shrouds required for the bus bars and the joints of different sizes. The slots also help to keep air flow around the joint to improve the heat dissipation as the joint is one of the hot points in the bus system. The shape of the shroud helps to insulate the joint from all directions.
[0033] FIG.l illustrates a top perspective view of a shroud mounted with a snap-fit mechanism according to one embodiment of the present invention. With respect to FIG. 1, shroud assembly 10 includes two vertical side plates 12 to insulate a surface of conducting material. Two side plates 12 are connected at the top by top plate 14. The two side plates 12 are provided with a pattern of slots to adjust the size of the shroud corresponding to the size of the bus bar assembly. The slots are arranged along the vertical and horizontal directions on the side plates so that the side plates are cut horizontally and vertically corresponding to the size of the bus bar assembly to adjust
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the size of the shroud with respect to the size of the bus bar assembly. Top plate 14 is provided with holes 15 to receive and fasten a snap-fit mechanism 20. Snap-fit mechanisms 20 are fastened to top plate 14 using projections 22 provided on the upper surface of the snap fit mechanism. Snap-fit mechanism 20 is mounted on the bus bar to hold shroud assembly 10 firmly over the bus bar joint and to prevent the movement of the shroud assembly.
[0034] FIG. 2 illustrates a top perspective view of a snap-fit mechanism mounted to the shroud in a shroud assembly according to one embodiment of the present invention. With respect to FIG. 2, snap-fit mechanism 20 is molded in inverted U-shape. Snap fit mechanism 20 includes a top portion 24 provided with two protrusions 22. Edges 26 of snap fit mechanism 20 are bent inwardly and resiliency to hold the bus bars firmly, when the snap fit mechanism is mounted on the bus bar assembly. Protrusions 22 provided on top portion 24 are inserted into the holes provided in the top portion of the shroud to fasten and to secure the snap fit mechanism with the top plate in the shroud. Snap-fit mechanism 20 is mounted on the bus bar to hold the shroud assembly firmly over the bus bar joint to prevent the movement of the shroud assembly.
[0035] FIG. 3 illustrates a top perspective view of snap-fit mechanism 20 mounted with a shroud in a shroud assembly according to one embodiment of the present invention. Snap-fit mechanism 20 is molded in inverted U-shape. Snap fit mechanism 20 has top portion 24 provided with projections 22. Projections 22 that are inserted into the holes provided in the top plate of the shroud to fasten and secure the snap fit
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mechanism 20 with the shroud. The front portion of snap fit mechanism 20 is formed with two pieces 29 that are attached to top portion 24 and are separated from each other. Snap fit mechanism 20 is provided with resilient edges 28 at the ends to hold the bus bars firmly to prevent the movement of the shroud, when the snap fit mechanism is mounted on the bus bar assembly. Edges 28 are bent outwardly. The pair of resilient edges 28 may act as springs to hold the bus bars tightly to prevent the movement of the shroud, when the snap fit mechanism is mounted on the bus bars.
[0036] FIG. 4 illustrates a front view of vertical side plate in the shroud according to an embodiment of the present invention. Vertical side plate 12 completely covers the joints on bus bars, when the shroud assembly is mounted on the bus bar assembly. Pluralities of slots 16, 18 are provided along the vertical and horizontal directions on the surface of the vertical side plate to adjust the size of the shroud with respect to the size of the of the bus bar assembly and the size of the joint on bus bar. Vertical slots 16 and horizontal slots 18 are provided so that the vertical side plates are cut horizontally and vertically corresponding to the size of the bus bar assembly to adjust the size of the shroud with respect to the size of the bus bar assembly.
[0037] The shroud can be cut vertically as well as horizontally along the slotted lines. Since the shroud can be cut on the slotted lines, the size of the shroud may be adjusted easily to suit the bus bar of any shape and size. This has reduced the need for the variety of shrouds required for the bus bars and the joints of different sizes. Slots 16, 18 also help to keep air flow around the joint to improve the heat dissipation as the joint is one of the hot points in the bus system. The shape of the shroud helps to insulate the joint from all directions.
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fabricated and assembled to the shroud easily thereby reducing the manufacturing time of the shroud assembly.
[0041] The shroud can be cut vertically as well as horizontally along the slotted lines. Since the shroud can be cut on the slotted lines, the size of the shroud may be adjusted easily to suit the bus bar of any shape and size. This has reduced the need for the variety of shrouds required for the bus bars and the joints of different sizes. The slots also help to keep air flow around the joint to improve the heat dissipation as the joint is one of the hot points in the bus system. The shape of the shroud helps to insulate the joint from all directions.
[0042] Although the invention is described with various specific embodiments, it will be obvious for a person skilled in the art to practice the invention with modifications. However, all such modifications are deemed to be within the scope of the claims.
[0043] It is also to be understood that the following claims are intended to cover all of the generic and specific features of the present invention described herein and all the statements of the scope of the invention which as a matter of language might be said to fall there between.

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CLAIMS
What is claimed is:
1. A shroud assembly for bus bar in switchboard comprising: a shroud; and a
snap fit mechanism connected to the shroud;
wherein the snap fit mechanism is pre assembled and connected to the shroud to form a single integral structure and the shroud is cut to any size based on the size of the bus bar assembly.
2. The assembly according to claim 1, wherein the shroud has two vertical side walls that are connected at the top by a top wall.
3. The assembly according to claim 1, wherein the two vertical side walls have slots arranged on the surface along the vertical and horizontal directions.
4. The assembly according to claim 1, wherein the shroud is cut along the slots so that the size of the shroud is adjusted based on the size of the bus bar assembly.
5. The assembly according to claim 1, wherein the shroud has holes on the top plate to receive and click fit the snap fit mechanism.
6. The assembly according to claim 1, wherein the snap fit mechanism is a molded component.
7. The assembly according to claim 1, wherein the snap fit mechanism is provided with two protrusions at the top.
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8. The assembly according to claim 1. wherein the protrusions are inserted into the holes provided at the top plate of the shroud to secure and fix the snap fit mechanism with the shroud.
9. The assembly mechanism according to claim 1, wherein the snap fit mechanism has resilient bent edges to hold the bus bar firmly to prevent the movement of the shroud, when the shroud is mounted on the bus bar assembly.

10. The assembly according to claim I, wherein the resilient edges of the snap fit mechanism are bent inwardly to hold the bus bars tightly upon the clamping of the snap fit mechanism on the bus bar assembly.
11. The assembly according to claim 1, wherein the resilient edges are bent outwardly to hold the bus bars tightly upon the clamping of the snap fit mechanism on the bus bar assembly.
12. The assembly according to claim 1, wherein the front portion of the snap fit mechanism is molded to form two pieces that are separated from each other.

Rakesh Prabhu,
Patent Agent, ALMT Legal,
No.2, Lavelle Road, BangaIore-560 001, INDIA
Dated this 18th of March, 2009

To,
The Controller of Patents,
The Patent office, Mumbai

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