FORM 2
The Patents Act 1970 (39 of 1970)
&
The Patent Rules 2003 PROVISIONAL SPECIFICATION
(See Section 10 and rule 13)
TITLE OF THE INVENTION:


RACKING SHIELD WITH CLICK-FIT ARRANGEMENT
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 a provision for a click-fit arrangement of a cover provided for ingression/shrouding of the racking arrangement of a circuit breaker. More particularly, the invention relates to a racking shield/cover, which has screw less mounting arrangement i.e. snap-fit type of arrangement for fixing the shield/cover on the racking arrangement.
B) BACKGROUND OF THE INVENTION
[0002] The switchgear is a common name used for metal-enclosed power circuit breakers. The switchgear generally contains circuit breakers of removable or rack out types and are contained in an individual grounded metal compartments.
[0003] The circuit breakers found in switchgear, distribution centers, and service entrance equipment are generally of three types such as molded case circuit breakers, insulated case circuit breakers, fixed or draw-out power circuit breakers. Some mechanical means, such as racking devices, are employed to rack-in or withdraw these large circuit breakers.
[0004] Circuit-breaker mounting assembles are equipped with a racking mechanism that properly positions the power circuit breaker and holds it rigidly in connected, test, and fully disconnected positions. The breaker modules are generally accessible for removal and replacement. The circuit breakers are provided with an integral racking mechanism.
2

[0005] During the transportation of mechanism components, the components need to be safeguarded from the ingression of the foreign particles like the wire strips, ferrules or washers falling in the path of the travel. Manytimes racking cover needs to be removed for the mounting of the accessories like interlocking locks or during the maintenance for applying grease to the racking arrangement. If the cover is screw fixing type, then there is possibility that end-user may forget to tight the screws, lead to interference with the other components of the breaker.
[0006] None of the prior art discloses a click-fit type or snap-fit type racking shield arrangement. Hence there is a need to develop a click-fit type or snap-fit type racking shield arrangement that would protect the racking arrangement from the ingression of the foreign particles like the wire strips, ferrules or washers falling in the path of the travel of the mechanism components. There is further need to provide a click-fit type or snap-fit type racking shield arrangement that can be removed and refitted by user for the mounting of the accessories like interlocking locks or during the maintenance for applying grease to the racking arrangement.
[0007] The abovementioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and studying the following specification.
C) OBJECTS OF THE INVENTION
3

[p008] The primary object of the present invention is to provide a cover to shroud the racking mechanism arrangement.
[0009] Another object of the present invention is to provide releasable/ re-fittable cover with snap-fit/click-fit type of construction.
[0010] Yet another object of the present mvention is to provide insertion of cover on the racking mechanism without use of any hardware i.e. screws type of fixing.
[0011] Yet another object of the invention is to provide locking means such that a predetermined minimum force is sufficient for removal.
[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.
D) SUMMARY OF THE INVENTION
[0013] According to an embodiment of the present invention, the racking cover comprises of a base plane and two limbs protruding transversely from the base plane and one limb normal to vertical plane. Limbs comprise of latch profiles protruding out in a lateral manner from the limbs located on the base plane. The entire racking arrangement is mounted on a base plate.
4

[0014] The base plate assembly comprising screw shaft support provided with circular protrusions in which racking cover adopting the latch profile gets snap-fitted. Circular protrusions ribs are provided on the surface of the pin of the base plate assembly for co¬operative latching and keeping the cover at desired position. A racking cover is provided with a flexible rib at the center with a groove where semi circular protrusion ribs provided on the circular portions of the enclosures get latched and keep the device at the position when the cover is mounted in a transverse manner on the base plate assembly. The flexible rib provided on the racking cover is an integral part of the racking cover. For removal of the cover, a force of appropriate magnitude is sufficient to unlatch the device from the base plate assembly.
[0015] 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 DRAWING
[0016] 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:
[0017] FIG. 1 illustrates the isometric view of the racking cover according to one embodiment of the present invention.
5

[0018] FIG. 2 illustrates the front view of the racking cover according to one embodiment of the present invention.
[0019] FIG. 3 illustrates the top view of the racking cover according to one embodiment of the present invention.
[0020] FIG. 4 illustrates the right hand side view of the racking cover according to one embodiment of the present invention.
[0021] FIG. 5 illustrates the isometric view of the snap fit-1 on vertical limb.
[0022] FIG. 6 illustrates the enlarged view of the snap fits on vertical limb.
[0023] FIG. 7 illustrates the isometric view of the snap fit-2 on vertical limb.
[0024] FIG. 8 illustrates the view of the snap fit on horizontal limb.
[0025] FIG. 9 illustrates the view of the snap fit on horizontal limb.
[0026] FIG. 10 illustrates an enlarged assembly view with vertical snaps.
[0027] FIG. 11 illustrates an enlarged assembly view with horizontal snaps.
6

[0028] 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
[0029] In the following detailed description, 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 and 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.
[0030] According to an embodiment of the present invention, the racking cover comprises of a base plane and two limbs protruding transversely from the base plane and one limb normal to vertical plane. Limbs comprise of latch profiles protruding out in a lateral manner from the limbs located on the base plane. The entire racking arrangement is mounted on a base plate.
[0031] The base plate assembly comprising screw shaft support provided with circular protrusions in which racking cover adopting the latch profile gets snap-fitted. Circular
7

protrusions ribs are provided on the surface of the pin of the base plate assembly for co-operative latching and keeping the cover at desired position. A racking cover is provided with a flexible rib at the centre with a groove where semi circular protrusion ribs provided on the circular portions of the enclosures get latched and keep the device at the position when the cover is mounted in a transverse manner on the base plate assembly. The flexible rib provided on the racking cover is an integral part of the racking cover. For removal of the cover, a force of appropriate magnitude is sufficient to unlatch the device from the base plate assembly.
8
. The detailed description and various embodiments of the invention along with the Claims shall be provided in the Complete Specification.