Claims:WE CLAIM:

1. An assembly for restricting the movement of the withdrawable modules in an electric panel board having a door (D) to a housing, wherein the housing comprises at least a module with Short circuit Protection Device (SCPD), wherein the said assembly comprising:

an interlocking plate (I) having a slot on it, wherein the slot is of a first shape (Is1);
a racking screw (R) having a special profile in the area where the interlocking plate (I) travels along the screw while the door (D) is opening and closing;
a spring (S) loaded on the interlocking plate (I);
wherein the interlocking plate (I) is configured to function as a lever to engage the interlocking plate (I) with the racking screw (R); and
wherein the special profile of the racking screw (R) comprises at least two shapes (Rs1, Rs2) wherein one of the shapes is same as the first shape (Is1) of the interlocking plate.

2. The assembly as claimed in claim 1, comprising a shutter to cover the access of the mechanism to the module when the door (D) is in open state.

3. The assembly as claimed in claim 2, wherein the interlocking plate (I) functioning as a lever is configured to operate the shutter to cover and uncover the module.

4. The assembly as claimed in claim 1, wherein the racking screw (R) comprises an area of a first shape (Rs1) at the portion of the racking screw (R) that is closer to the door (D) and an area of a second shape (Rs2) at the portion that is farther from the door (D).

5. The assembly as claimed in claim 1, wherein the first shape (Rs1) of the racking screw (R) is the same as the first shape (Is1) of the interlocking plate (I).

6. The assembly as claimed in claim 1, wherein the first shape (Rs1) of the racking screw (R) and the first shape (Is1) of the interlocking plate (I) are hexagonal.

7. The assembly as claimed in claim 1, wherein the second shape (Rs2) of the racking screw (R) is circular.

8. The assembly as claimed in claim 1, wherein the interlocking plate (I) is configured to engage the slot of first shape (Is1) of the interlocking plate with the area of the second shape (Rs2) of racking screw (R) when the door (D) is in closed state.

9. The assembly as claimed in claim 8, wherein the racking screw (R) is configured to be rotated to change the position of the module from one position to another position.

10. The assembly as claimed in claim 1, wherein the spring (S) is configured to push the interlocking plate (I) outwards the housing.

11. The assembly as claimed in claim 10, wherein the interlocking plate is configured to engage the slot of first shape (Is1) of the interlocking lever with the area of the first shape (Rs1) of racking screw when the door (D) is in open state.

12. The assembly as claimed in claim 11, wherein the racking screw (R) is configured to prevent its rotation to restrict the movement of the module.

13. An electric panel board comprising:
a housing enclosing least a module with Short circuit Protection Device (SCPD); and
the assembly as claimed in any one of the claims 1 to 12.

Dated this 30th day of March 2019

Abhishek Sen
Of S. Majumdar & Co.
(Applicant’s Agent)
Registration No. 980

, Description:TECHNICAL FIELD OF THE INVENTION

The present subject matter described herein relates generally to racking in electrical panel board, and, more particularly, to an assembly that restricts the operation of withdrawable module in panel board when the door is in open state.

BACKGROUND OF THE INVENTION

An electric panel board (also known as distribution board, breaker panel, or electric panel) is a component of an electricity supply system that divides an electrical power feed into subsidiary circuits, while providing a protective fuse or circuit breaker for each circuit in a common enclosure. In a panel board, module with Short Circuit Protection Device (SCPD), contactor, relay are provided for operation, control and protection of loads like motor, pumps, conveyors etc are also present. The modules may also be of withdrawable type. The panel houses the different electrical and electronic components in housing such as a compartment. The housing may also be provided with a door.

For the purpose of withdrawing the modules in the panel, racking mechanism is provided to take module from one position to other. The mechanism can either be open door or closed door type. There are three positions of a module: Isolated, Test and Service. In closed door operation of the module, the door is closed throughout the operation of the module. There can be situations where it becomes necessary to open the door even when the module is in service position (e.g. taking thermal data) or in test position. In such situations, operation of module from one position to other should be restricted to avoid unsafe operation of the module.

In view of the aforementioned situation, reference is made to US8212164 that discloses about an assembly for preventing a racking operation if a door of a compartment of switchgear that houses a circuit breaker is not completely closed. In this prior art, it is disclosed that the racking screw is divided into two parts, one member connected to the module with a protruding pin and coupling member on the door. When the door is closed, the pin on the member connected to the module gets engaged to the coupling member on the door and racking is possible. When the door is open, the two members are disconnected and racking cannot be done.

Further, reference is made to CN103956668BA that discloses a low-pressure propulsion modular withdrawable drawer interlock mechanism that provides for the access to the racking mechanism to be restricted when the door is open.

However, the constructional features of both the prior art involves a number of components that not only increases the constructional complexities of the solution but also increases the cost involved in its manufacture.

Therefore, there is a dire need to provide an efficient, reliable, simple, and cost effective solution that restricts the operation of modules in an electrical panel board from one position to other so as to facilitate safe operation of the modules.

SUMMARY OF THE INVENTION

The following disclosure presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.
An object of the present invention is to overcome the drawbacks of the prior art of the invention.

Another object of the present invention is to provide an assembly for restricting the movement of the withdrawable modules in operation an electric panel board when the door is open.

Yet another object of the present invention is to provide an efficient, simple, and cost effective solution to restrict the movement of the modules in a panel board when in operation.

Briefly, various aspects of the subject matter described herein are directed at an assembly for restricting the movement of the withdrawable modules in an electric panel board having a door to a housing, wherein the housing comprises at least a module with Short circuit Protection Device (SCPD), wherein the said assembly comprising an interlocking plate having a slot on it, wherein the slot is of a first shape; a racking screw having a special profile in the area where the interlocking plate travels along the screw while the door is opening and closing; a spring loaded on the interlocking plate; wherein the interlocking plate is configured to function as a lever to engage the interlocking plate with the racking screw; and wherein the special profile of the racking screw comprises at least two shapes wherein one of the shapes is same as the first shape of the interlocking plate.

Other salient features and advantages of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which:

Figure 1 illustrates the profile of the interlocking plate in accordance with the present invention.

Figure 2 illustrates the profile of the racking screw in accordance with the present invention.

Figure 3 illustrates the position of the interlocking plate and the racking screw when the door is in open state in accordance with the present invention.

Figure 4 (a) illustrates the top view of the module of the assembly comprising the interlocking plate, spring and the racking screw when the door is in open state in accordance with the present invention.

Figure 4 (b) illustrates the front view of the profile of the engaged position of the slot of the interlocking plate and the racking when the door is in open state in accordance with the present invention.

Figure 5 (a) illustrates the top view of the module of the assembly comprising the interlocking plate, spring and the racking screw when the door is in closed state in accordance with the present invention.

Figure 5 (b) illustrates the front view of the profile of the engaged position of the slot of the interlocking plate and the racking when the door is in closed state in accordance with the present invention.

Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary.

Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

The terms and words used in the following description are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by their equivalents.

It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

By the term “substantially” wherever used or will be used later it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

In one embodiment of the present invention is provided an assembly for restricting the movement of the withdrawable modules in an electrical panel board having a door (D) to housing. The housing may be a compartment and may comprise at least a module with Short circuit Protection Device (SCPD). The components in the housing are secured by means of the door (D), which can be opened and closed. Assembly comprises of modules for interlock. The interlock is provided for the closed door operation of the module ensuring that the operation of the module is possible only when the door is in closed state. When the door is open, a spring loaded lever protrudes out of the module.

In another embodiment of the present invention is provided an assembly that comprises an interlocking plate (I) having a slot on it and a racking screw (R) having a special profile in the area where the interlocking plate travels along the screw while the door is opening and closing, which may be referred to as the open state and closed state respectively of the door (D). The assembly further comprises a spring (S) loaded on the interlocking plate (I). The interlocking plate is configured to function as the spring loaded lever.

Further, as per an embodiment of the present invention, the interlocking plate (I) with the slot on it is disclosed in figure 1. The slot of the plate is of a first shape (Is1). The profile of the slot having the first shape (Is1) is preferably hexagonal, as depicted in figure 1. The assembly comprises the racking screw (R) having a special profile in the area where the interlocking plate (I) travels along the screw while the door is in open state and closed state. The special profile of the racking screw (R) comprises at least two shapes secured with a collar (C) as is illustrated in figure 2. The racking screw (R) comprises an area of a first shape (Rs1) at the portion of the racking screw that is closer to the door and an area of a second shape (Rs2) at the portion farther from the door. As per the present invention one of the shapes of the profile of the racking screw (R) is same as that of the shape of the slot in the interlock plate (I). The first shape (Rs1) of the racking screw and the first shape (Is1) of the interlocking plate are the same. The special profile of the racking screw (R) is having the first shape (Rs1) of the racking screw as preferably hexagonal and the second shape (Rs2) of the racking screw as preferably circular. In present invention, access to handle may not be restricted. No shutter is operated and the access is not restricted when the door is opened. Instead, the hexagonal profile of interlock assembly is aligned with hexagonal profile of racking screw when the door is opened. There is antirotation between the two. Thus, racking screw cannot be rotated and module cannot be moved from one position to other.

In an embodiment of the present invention, it is disclosed that the racking screw (R) is inserted through the spring loaded interlocking plate with hexagonal slot provided on it. The hexagonal racking screw has special profile in the area where the interlocking plate travels along the screw while door is opening and closing. When the door (D) is closed, the interlocking lever gets pushed in. The hexagonal slot of the interlocking lever enters in the area where racking screw (R) has circular profile. Thus, racking screw can be rotated and module can be taken from one position to other. When the door is opened, the spring pushes interlocking lever outside. In this case, the hexagonal slot of the interlocking plate (I) gets matched with the hexagonal profile of the racking screw (R). Thus, the screw cannot be rotated and module position cannot be changed in door open condition.

In a situation before the door gets into closed position i.e. when the door (D) is open, the position of interlocking lever (I) and racking screw (R) with respect to each other is as shown in figure 3. When the door moves into closed state from here, the interlocking plate functioning as the spring loaded lever gets pushed in, and the spring (S) is compressed. The hexagonal profile of the interlocking lever is in the circular profile of the racking screw (R). This condition is shown in figures 5(a) and 5(b). Figure 5 (a) shows the top view of the module of the assembly comprising the interlocking plate, spring and the racking screw when the door is closed. Further, figure 5 (b) shows the front view of the profile of the engaged position of the slot of the interlocking plate and the racking when the door closed. The arrow marked as ‘b’ in figure 5(b) indicates that the hexagonal slot on the interlock and the circular profile of the racking screw are matching. In this condition, the spring loaded lever is pushed inside and facilitates for uncovering the mechanism of the module. Thus, in this condition, the racking screw (R) can be rotated and module position can be changed.

When the door (D) moves from closed state to open state, the spring (S) pushes the interlocking lever out and hexagonal slot of the lever matches with the hexagonal profile of the racking screw as shown in figures 4(a) and 4(b). Figure 4 (a) shows the top view of the module of the assembly comprising the interlocking plate, spring and the racking screw when the door is open and figure 4 (b) shows the front view of the profile of the engaged position of the slot of the interlocking plate and the racking when the door is open in accordance with the present invention. The arrow marked as ‘a’ in figure 4(b) indicates that the hexagonal slot on the interlock and the hexagonal profile of the racking screw are matching. In this condition, the spring loaded lever protrudes out of the module. This lever operates the shutter to cover the access of the mechanism when the door (D) is open. Thus, the racking screw (R) cannot be rotated in this condition. Thus, module position cannot be changed.

It is because of anti-rotation between two parts that the racking cannot be done when the door is open. When the door is closed, the hexgonal slot of the interlocking component comes out of the hexagonal profile of the racking screw and racking screw can be rotated.

Some of the noteworthy features of the present invention are mentioned below:

1. When the door of the housing of the withdrawable module is open, even if the operating handle is inserted, the racking screw cannot be rotated.
2. When the door of the housing is open, the module position cannot be changed.
3. When the door of withdrawable module is open, anti rotation between racking screw and interlocking component is achieved. This prevents the rotation of racking screw when the door is open

Some of the non-limiting advantages of the present invention over the prior art are mentioned below:
1. The present invention is reliable, simple and easy in construction and is cost effective in nature.
2. The present invention does not allow operation of the module when the door is open, thus ensuring protection of the persons operating modules and prevention of unsafe operation.

List of reference numerals and the corresponding features used herein:

R: Racking Screw
S: Spring
I: Interlocking plate
D: Door
C: Collar
IS1: Shape of the interlocking plate profile
RS1 and RS2: Shapes of the racking screw profile