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: IMPROVED HINGE ASSEMBLY FOR AN ELECTRIC
PANEL BOARD
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:

TECHNICAL FIELD OF THE INVENTION
The present invention relates generally to an electric panel board. More particularly the present invention relates to an improved hinge assembly for an electric panel board to hold one side of door thereby enabling free swinging.
BACKGROUND AND THE PRIOR ART
The main function of electric panel board is to distribute electricity through a number of outgoing feeders each of which has multiple compartments of varying sizes and so different dimensions of door are used in the assembly of panel. The compartment door is assembled to the switchboard enclosure using a number of hinges depending on the height of the door.
The different functions of hinge are as follows:
a. Primary Function:
-To hold one side of the door and enable it to swing freely at the other end.
b. Secondary Functions:
-To allow the door to open with adequate space for easy access.
-To allow the proper closing and opening of doors.
-To withstand the weight of the door and other equipment assembled on the door.
-To allow or prevent easy removal of the door.
-To provide an aesthetic look to the switchboard.
-To hold the door open during maintenance
-To maintain the door in close position during external force acting on the door,
especially during transport or incase of arcing faults or seismic vibrations.
The basic requirement of hinge is to hold the door and allow the door to open at certain angle. A hinge assembly including first and second hinge portions that are pivotable relative to one

another about a fixed axis. Normally, the piece that connects the both first & second part is called pin, which allows the rotational movement of one part while holding other in its original position. The door is fixed to the movable part of the hinge by means of screwing, welding etc. The force balancing component in the hinge assembly is only the rotational part connected with fixed part. Hence the shape and design of hinge should be such that it will withstand the forces even under high-pressure conditions of arcing faults and seismic vibrations.
The present invention therefore provides an improved hinge assembly for an electrical panel board that Combination features of both concealed and exposed type hinge. It provides a Lock-in feature in the main finger type hinge. Also, Connector mounting plate can be changed as per requirement of aesthetic look without altering other parts. Load balancing feature is provided during closed condition of the door.
OBJECTS OF THE INVENTION
A basic object of the present invention is to overcome the disadvantages/drawbacks of the known art.
Another object of the present invention is to provide an improved hinge assembly for an electric panel board to hold one side of door thereby enabling free swinging.
Other object of the present invention is to provide a lock in feature.
Other object of the present invention is to provide a load balancing feature in the hinge
assembly.
Yet another object of the present invention is to allow adequate opening and closing of the
door.

These and other advantages of the present invention will become readily apparent from the following detailed description read in conjunction with the accompanying drawings.
SUMMARY OF THE INVENTION
There is provided a hinge assembly for an electrical panel board.
According to one embodiment of the present invention, there is provided A hinge assembly for an electric panel board to hold one side of door thereby enabling free swinging, said assembly comprising a main hinge having a plurality of fixing holes (1,2) and a plurality of ribs adapted to withstand stress; a connector hinge fixed to a connector mounting plate with a plurality of screws mounted on fixing holes, said connector mounting plate having a substantially curved edge adapted to achieve attachment with said door thereby preventing lateral movement of said mounting plate; an insert pin placed in a cut provided on said main hinge on alignment of knuckle holes of said connector hinge and said main hinge; wherein said main hinge providing a gap for rotation of doors without any interference with door gasket and a substantially curved cut provided near a knuckle (11) adapted to lock said door during opening.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The following drawings are illustrative of particular examples for enabling methods of the present invention, are descriptive of some of the methods, and are not intended to limit the scope of the invention. The drawings are not to scale (unless so stated) and are intended for use in conjunction with the explanations in the following detailed description.
Fig 1 illustrates the hinge assembly in accordance with the present invention. It shows fixing
holes, ribs, slot cut etc.

Fig 2 illustrates the main hinge having a substantially 'ω' shaped insert cut (6, 7) allowing said screws to rest thereby preventing interference.
Fig 3 illustrates the shape of main hinge of the form of a folded finger (10), which provides sufficient gap for rotation of doors without any interference with door gasket thus prolonging
the life of the gasket.
Fig 4 illustrates the lock in feature achieved by providing a curve cut near the knuckle (11), where the door gets locked during opening.
Fig 5 illustrates the connector hinge having fixing holes (15, 16) which is fixed with connector mounting plate using screws.
Fig 6 illustrates the connector mounting plate.
Fig 7 illustrates the entire hinge assembly.
DETAILED DESCRIPTION OF THE INVENTION
Accordingly in the present invention door hinge which has to meet the functional requirements as well as to enhance the board aesthetics is provided. Hinge design is not only affected by the door construction but also by the location and the construction of the pillar where the hinges are going to be mounted. In such a case, where the mounting pillar is completely placed inside the switchboard and the hinge is required to be made visible from outside, the design of hinge becomes very complicated.
This is partially-exposed type hinge i.e. the hinge is fixed inside the panel but can be made visible from outside without affecting ingress protection. By ingress protection, it implies that no ingress of dust and water drops is possible inside the panel once the hinge is assembled and the door is closed.

The placement of the hinge depends on the shape of the mounting pillar which facilitates the panel designer to place the hinge onto the pillar. Presently, the pillar used does not have any fixing means on its front face which makes it rather difficult to assemble the hinge while making it visible on the outside. This invention overcomes this problem in which a portion of the hinge is mounted to internal pillar and the second part is screwed to connector mounting plate through door which is on the front face of the door and visible from outside with the door in closed position.
The invented hinge consists of main bent L-shaped hinge (fig. 1), connector hinge (fig. 5), connector mounting plate (fig. 6) and the insert pin. The main hinge has fixing holes (1, 2), which is fixed to internal vertical pillar. The connector hinge is fixed to connector mounting plate (fig. 6) with screws and the mounting plate will be attached on the surface of door.
In the present scenario, due to frequent opening and closing of the door, the gasket may get worn out much earlier than its intended life-time due to very small clearance between the hinge and the gasket. In the invented hinge, the shape of main hinge (fig.l & fig. 4) is of the form of a folded finger (10), which provides sufficient gap for rotation of doors without any interference with door gasket thus prolonging the life of the gasket.
The main finger type hinge is provided with lattice type ribs (3) which provide greater strength to withstand the stresses due to external and internal forces. The connector hinge (fig. 5) has fixing holes (15,16) which is fixed with connector mounting plate using screws and thus welding is not required for fixing of door with hinge as is the case with the present design. Connector mounting plate is designed in order to allow the fixing of the connector hinge with door without affecting the ingress protection of the switchboard. The door portion is safely sandwiched between connector hinge and connector mounting plate. Simply put, this plate acts as nut plate for fixing the connector hinge to the door. An edge curve (17) is provided on connector mounting plate in order to achieve proper attachment with the door which will not allow the mounting plate to move laterally. The'complete assembly is shown in the fig.7.

As connector mounting plate is mounted on the door and visible from outside, it provides an aesthetic differentiation as compared to the present design. This hinge provides the combination feature of both concealed and exposed type hinge, where it is fixed inside the door but its supporting connector mounting plate is visible from outside.
The cut chamfer shape (14) of connector hinge allows the rotation of door without interfering with main hinge and also withstanding the door weight in both open and closed condition. Main hinge is provided with 'ω' shaped insert cut (6,7), which allows the screws to rest inside while providing zero interference with screw during closing the door.
After closing the door, connector hinge gets inserted in the slot cut (5, 9) in the main hinge and the circular surface of connector hinge (12) gets inserted in the main hinge. Hence, the entire door weight and forces acting on it, will be distributed in both main and connector hinge. The main hinge has a round cut (4) to place the insert pin. After alignment of the knuckle holes of the connector hinge and main hinge, the pin is inserted.
To avoid the inadvertent removal of door during normal opening of the door, a lock-in feature provided in the main hinge prevents this condition. The lock in feature is achieved by providing a curve cut near the knuckle (11), where the door gets locked during opening. Each part of hinge can be assembled independently so replacement of any part is possible without affecting/damaging the any other parts which is not the case with the present design.
The invented hinge provides ease of assembly, thereby reducing the total assembly time. Overall cost of hinge assembly is reduced due to elimination of the welding process. Due to elimination of welding, it is possible to adjust the alignment and fixing of the door with main hinge thereby allowing higher tolerances in assembly.

INTENDED ASSEMBLY FOR THE INVENTION:
Step 1: Fix Bent L-shaped hinge to interna) vertical pillar
Step 2: Align the hole of connector hinge and door hole, insert screw and tight it to Connector mounting plate.
Step 3: Align the connector hinge assembled in the door in the main hinge and insert the connector pin the hole.
FEATURES:
• Combination features of both concealed and exposed type hinge.
• Lock-in feature is provided in the main finger type hinge.
• Connector mounting plate can be changed as per requirement of aesthetic look without altering other parts.
• Ingress protection is achieved.
• Load balancing feature is provided during closed condition of the door.
• Ease of assembly and replacement of the parts.
• Lattice type rib improves the strength without affecting the assembly of the parts.
• Restriction of the movement of mounting plate achieved by the edge curved feature (17).
Although the embodiments herein are described with various specific embodiments, it will be obvious for a person skilled in the art to practice the embodiments herein with modifications. However, all such modifications are deemed to be within the scope of the claims.
It is also to be understood that the following claims are intended to cover all of the generic and specific features of the embodiments described herein and all the statements of the scope of the embodiments which as a matter of language might be said to fall there between.

WE CLAIM:
1. An improved hinge assembly for an electric panel board to hold one side of door thereby enabling free swinging, said assembly comprising:
a main hinge having a plurality of fixing holes (1,2) and a plurality of ribs adapted to
withstand stress;
a connector hinge fixed to a connector mounting plate with a plurality of screws mounted on fixing holes, said connector mounting plate having a substantially curved edge adapted to achieve attachment with said door thereby preventing lateral movement of said mounting plate;
an insert pin placed in a cut provided on said main hinge on alignment of knuckle holes of said connector hinge and said main hinge;
wherein said main hinge providing an appropriate gap for rotation of doors without any interference with door gasket and a substantially curved cut provided near a knuckle (II) adapted to lock said door during opening.
2. Assembly as claimed in claim 1 wherein said main hinge is substantially bent L shaped hinge.
3. Assembly as claimed in claim 1 wherein said main hinge is fixed to an inner vertical
pillar.
4. Assembly as claimed in claim 1 wherein said mounting plate attached to said door.

5. Assembly as claimed in claim 1 wherein said ribs are substantially lattice type ribs.
6. Assembly as claimed in claim 1 wherein said door is substantially sandwiched between said connector hinge and said connector mounting plate.
7. Assembly as claimed in claim 1 wherein said connector hinge having substantially a cut chamfer shape (14) adapted to provide rotation of said door without interfering with said main hinge and withstanding door weight both in open and closed condition.
8. Assembly as claimed in claim 1 wherein said main hinge having a substantially 'ω' shaped insert cut (6, 7) allowing said screws to rest thereby preventing interference with said screw during closing of said door.
9. Assembly as claimed in claim 1 wherein said connector hinge adapted to insert in slot cut (5, 9) provided on said main hinge on closing said door thereby distributing
weight of said door.
10. A hinge assembly for an electric panel board to hold one side of door thereby
enabling free swinging as herein described and illustrated with reference to
accompanying drawings.