Claims:1. A draw-out relay assembly (1) with cam mechanism, comprising:
a draw-out relay (3) and a fixed frame (2) with front face open through which said draw-out relay (3) is inserted and removed from said fixed frame (2);
fixed frame contacts (4) and moving contacts (7);
a handle (11) acting as mechanical actuator;
a pin rail (6) consisting of cam profile mounted on either side of the fixed frame (2);
wherein said pin rail (6) is configured to stop the hollow pin (12) to avoid unintentional rack-in of the said relay when the handle (11) is not lifted;
a square pin (13); a handle plate (14);
wherein said square pin (13) is adapted for providing required degree of offset to said handle (11) and said handle plate (14) to eliminate back travel in mechanism operation;
a hollow pin (12);
wherein said hollow pin (12) aligns with the said pin rail (6) slot for controlling racking in/out of said draw-out relay (3) when handle (11) is lifted.

2. A draw-out relay assembly (1) as claimed in claim 1 wherein said cam profile is adapted to control the contact movement.

3. A draw-out relay assembly (1) as claimed in claim 1 wherein said fixed frame (2) includes a rear wall comprising set of fixed frame contacts (4) opposite to the front open face.

4. A draw-out relay assembly (1) as claimed in claim 1 wherein said draw-out relay (3) includes a rear wall comprising a set of moving contacts (7) opposite to the front fascia assembly (9).

5. A draw-out relay assembly (1) as claimed in claim 1 wherein said fixed frame (2) and said draw-out relay (3) comprising cooperating first and second sections (4,7) that are engaged with one another when said draw-out relay (3) is fully inserted within said fixed frame (2), said fixed frame contacts (4) and moving contacts (7) being separated by removing said draw-out relay (3) from said fixed frame (2).
6. A draw-out relay assembly (1) as claimed in claim 1 includes a front fascia assembly (9) adapted to display relay condition and to feed set of instructions as per the requirement for the efficient functioning of the said relay.
7. The front fascia assembly (9) as claimed in claim 6 optionally consisting of a USB port for connecting the relay to any device for transferring the information from the relay to other devices like a smart phone or a PC.
8. A draw-out relay assembly (1) as claimed in claim 1 wherein said fixed frame (2) is a molded insulating structure.
9. A draw-out relay assembly (1) as claimed in claim 1 wherein said fixed frame (2) and draw-out relay (3) each include a set of plug-in type contact (4,7) that extends forward from said rear wall of the said fixed frame and draw out-relay and said set of fixed frame contacts (4) and moving contacts (7) each having a socket positioned to receive the plug-type contacts when the draw-out relay (3) is fully inserted into said fixed frame (2).
, Description:TECHNICAL FIELD
The present invention generally relates to a relay. In particular, the invention relates to a mechanism which controls contact insertion and removal of draw-out relay.

BACKGROUND AND PRIOR ART
A relay is an electrical switch with electromagnet or solid state devices along with required logic inbuilt to operate the main switch for an intended function. In protective relay, relay device designed to trip a circuit breaker when it detects an abnormal operating conditions such as over-current, over-voltage, reverse power flow, over-frequency, and under-frequency fault is detected.
The feeder protection relays are widely used at the feeder levels in electrical circuits for monitoring the effective functioning of feeder. For making feeder protection relay maintenance, supportive draw-out type is made. The feeder protection relays are widely used at the feeder levels in an electrical circuit for the monitoring the effective functioning of feeder. The draw-out type relay has fixed frame and removable relay. Fixed frame has different fixed contacts (CT, DIO, connectors, etc.) which will make contact with moving relay when inserted and provide supply. Each time when the relay is removed or inserted the contact will experience stress because of operating force in addition to normal contact engagement forces.
Document US 8119943 B2 discloses draw-out mechanism for molded case circuit breaker with a fixed side plate configured to mount the circuit breaker within a Switchgear cabinet; an auxiliary contact system mounted to the fixed side plate, the auxiliary contact system including an activated member and auxiliary contacts switchable between a first position and a second position. Further it comprises of a movable member moveably mounted to the fixed side plate, the movable member being moveable between a first position wherein the circuit breaker is in a connect configuration, and a second position wherein the circuit breaker is in a disconnect configuration; and a cam member fixedly mounted relative to the movable member, the cam member actionable upon the activator member to switch the auxiliary contacts between the first and second positions in response to a movement of the circuit breaker between the connect configuration and the disconnect configuration.

Document US 4742428 discloses a protective relay apparatus which is constructed of an operating unit that is withdrawable from its insulating housing through an opening at the front thereof. A plurality of sets of shorting contacts and a plurality of plug-type disconnect contacts are mounted to the rear wall of the housing and extend forward therefrom. Mounted on the draw-out unit rear panel are a plurality of receptacle type contacts that receive and cooperate with the dis connect contacts when the draw-out unit is inserted fully within the housing. At that time blade means mounted in the draw-out unit are interposed between contact sections of the respective sets of shorting contacts to separate contact portions of the latter.

Document CN102097257A discloses a moulded case circuit breaker (MCCB) with self-locking function. It provides a moulded case circuit breaker (MCCB) with self-locking function. The MCCB comprises an MCCB body, a user input unit, an authentication processing unit and a deadlocking acting unit, wherein the user input unit is used for inputting a deadlocking password or an unlocking password; the authentication processing unit is used for receiving the deadlocking password or unlocking password from the user input unit and outputting a control signal after authenticating the deadlocking password or unlocking password; and the deadlocking acting unit is used for receiving the control signal from the authentication processing unit and ensuring the MCCB body to carry out self-locking or unlocking.

The above mentioned documents discloses draw-out mechanism used to activate the auxiliary circuit inside plate to change state using cam mechanism, manual draw-out module operation and self-locking is achieved through a separate electronic unit called authentication processing unit. Contact system is the important part of a relay which experiences different stress during the operation. In addition to the required operation contact systems forces in draw-out type of relays, contact system will experience the force of operation during insertion and removal. If not controlled, this will add to the contact wear and contact life will be reduced.
Thus, in view of the above mentioned drawbacks, to protect contact from operating stress there is a need for controlling contact operation independent of operating force.

OBJECT OF THE INVENTION
An object of the present invention is to control contact insertion and removal force independent of operator force in a draw-out relay.
An object of the present invention is to provide controlled contact engagement.
Another object of the present invention is to provide a self-locking feature to prevent unintended operation.
Yet another object of the invention is to provide combined handle and mechanism actuator to minimize the number of components.
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
The following 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.
In accordance with the purposes of the present invention in one aspect there is embodied and broadly described a draw-out relay, which uses a cam mechanism which controls contact insertion and removal force and through the cam profile it provides insertion and removal force independent of the operator.
In one implementation, the present invention controls contact movement through the cam profile by not transferring operator operating force to contacts.
In one implementation, the present invention combines operating handle means to actuate the mechanism.
In another implementation, the invention uses a pin rail, which is configured to stop the hollow pin to avoid unintentional rack-in of the relay when the handle or the actuation mean is not lifted.
In another implementation, the invention uses a square pin which is adapted for providing required degree of offset to the handle and handle plate to eliminate back travel in mechanism operation.
In another implementation, the invention uses a hollow pin which aligns with the pin rail slot for controlling racking in/out of the relay when the handle of the relay is lifted.
Other aspects, advantages, and salient features 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
It is appreciated that the drawings provided in the present disclosure only illustrate application examples of the present disclosure and are therefore not to be construed as limiting its scope. The foregoing disclosure provides additional information with additional specificity and detail with the accompanying drawings, which are listed below for quick reference.
Figure 1 illustrates the isometric view of the entire product system, i.e. draw-out relay assembly in half inserted position, in accordance with an embodiment of the present disclosure.
Figure 2 illustrates the isometric view of draw-out relay showing fixed frame and draw-out relay in draw-out position, in accordance with an embodiment of the present disclosure.
Figure 3 shows the fixed frame assembly having contact system at the rear end, fixed frame and pin rail consisting of cam profile mounted on either side of the frame, in accordance with an embodiment of the present disclosure.
Figure 4 Shows the relay with moving contact mounted on the rear end of relay frame and front fascia assembly mounted on the front portion, in accordance with an embodiment of the present disclosure.
Figure 5 Shows the exploded view of the front fascia assembly, operating handle along with cam mechanism components, in accordance with an embodiment of the present disclosure.
Figure 6 Shows the side view of the assembly excluding frame when the handle is not lifted, in accordance with an embodiment of the present disclosure.
Figure 7 Shows the side view of the assembly excluding frame when the handle is lifted, in accordance with an embodiment of the present disclosure.
Figure 8 Shows the side view of the assembly excluding frame in which the handle is rotated in a downward direction to its original position, in accordance with an embodiment of the present disclosure.
Figure 9 illustrates a schematic view of the assembly in which fixed frame contacts and moving contact in engaging position and the handle in lock position with hollow pin, in accordance with an embodiment of the present disclosure.
Figure 10 illustrates the schematic view of the assembly which explains the sequence of operation from OFF to ON, in accordance with an embodiment of the present disclosure.
Figure 11 illustrates the schematic view of the assembly which explains the sequence of operation from OFF to ON, in accordance with an embodiment of the present disclosure.
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 INVENTION
It should be understood at the outset that although illustrative implementations of the present disclosure are illustrated below, the present invention may be implemented using any number of techniques, whether currently known or in existence. The present disclosure should be in no way limited to illustrative implementations, drawings, and techniques, illustrated below, including the exemplary design and implementation illustrated and described herein, but may be modified within the scope of equivalents.
Unless otherwise defined, all terms and especially technical and/or scientific terms, used herein, may be taken to have the same meaning as commonly understood by one having an ordinarily skilled in the art.
Reference is made herein to some “embodiments”. It should be understood that an embodiment is an example of a possible implementation of any features and/or elements presented in the foregoing claims. Some embodiments have been described for the purpose of illuminating one or more potential ways in which the specific features and/or elements of the foregoing claims fulfill the requirements of uniqueness, utility, and non-obviousness.
Figure 1 illustrates the isometric view of the entire product system, i.e. draw-out relay assembly in half inserted position, in accordance with an embodiment of the present disclosure.
The present disclosure discloses a draw-out relay assembly (1) with a cam mechanism which comprises of a draw-out relay (3) and a fixed frame (2) with front face open through which draw-out relay (3) is inserted and removed from the fixed frame (2).
Figure 2 illustrates the isometric view of draw-out relay showing fixed frame and draw-out relay in draw-out position, in accordance with an embodiment of the present disclosure.
Figure 3 shows the fixed frame assembly having contact system at the rear end, fixed frame and pin rail consisting of cam profile mounted on either side of the frame, in accordance with an embodiment of the present disclosure.
Figure 4 Shows the relay with moving contact mounted on the rear end of relay frame and front fascia assembly mounted on the front portion, in accordance with an embodiment of the present disclosure.
In one implementation, the present invention provides a draw-out relay, which uses a cam mechanism which controls contact insertion and removal force and through the cam profile it provides insertion and removal force independent of the operator.it controls contact movement through the cam profile by not transferring operator operating force to contacts.
In one implementation, the present invention provides controlled contacts operating force through a cam mechanism, hence insertion and removal force will be almost same in every operation and independent of operator force.
In one implementation, the present invention provides a mechanism operating handle (11) rotates to the required over-rotation position to in-cooperating the self-locking feature.
Figure 5 Shows the exploded view of the front fascia assembly, operating handle along with cam mechanism components, in accordance with an embodiment of the present disclosure. roller rivet (15), hollow pin (12), Handle plate (14) and square pin (13) are riveted one on either side of the front fascia (10). Handle (11) is checked to be free to rotate along with mechanism components handle plate (14) which carries rotating hollow pin (12). Rotating hollow pin (12) will helps in reducing the friction in cam operation. Handle (11) and handle plate (14) are offset to required degree using square pin (13) to eliminate back travel in mechanism operation.
In one implementation, the present invention discloses a front fascia assembly (9) configured to display relay condition and to feed set of instructions as per the requirement for the efficient functioning of the said relay. Inter fascia assembly (9) may comprise a set of press buttons for configuring the relay and for programming the relay as per the requirement. The front inter fascia assembly (9) may also consist of the USB port for connecting the relay to any device for transferring the information from the relay to the said device. Said device may be a smart phone or a PC.

Referring to Figure 6, it shows the side view of the assembly excluding frame when the handle is not lifted. This is initial rack-in stage where the pin rail (6) in fixed frame (5) stops the hollow pin (12) in the relay when the handle (11) is not lifted. This avoids unintentional rack-in.
Referring to Figure 7, it shows the side view of the assembly excluding frame when the handle is lifted. In this condition hollow pin (12) aligns with the pain rail (6) slot and will be ready to rack-in or out.
Referring to Figure 8, it shows the side view of the assembly excluding frame (2) in which the handle (11) is rotated in a downward direction to its original position. This action rotates the Handle plate (14) and the Hollow Pin (12) travels in the controlled Cam profile in the Pin Rail (6) taking the draw-out relay (3) towards the Fixed frame (2) and both the contact system (4) and (7) will get engaged.
Referring to Figure 9. It shows a schematic view of the assembly in which fixed frame contacts (4) and moving contact (7) in engaging position and the handle (11) in lock position with hollow pin (14) thus complete engagement occurs in pin rail (6) cam slot.
Referring to Figure 10, it shows the schematic view of the assembly which explains the sequence of operation from OFF to ON. In figure 10, Fixed Frame (2) is excluded. The operation starts with Draw-out relay (3) being racked into the Fixed frame (2). When the Draw-out relay (3) Handle (11) is not lifted Hollow Pin (12) will be stopped by Pin Rail (6) front surface as cam profile not aligned with the hollow pin (12) and contacts system (4) and moving contact (7) will not touch. Hence unintentional insertion will be avoided. Handle (11) has to be lifted up to align Hollow pin (12) into the cam slot. Then by Placing back the handle (11) in original location by pushing handle (11) down Draw-out Relay (3) moving inside fixed frame (2) in controlled force and relay moving contact (7) engages with the fixed frame (2) contact system (4) thus completing the operation. Hence, in all racks in operation only the cam operating force will be transferred independently of operator force of operation.
Referring to Figure 11, it illustrates the schematic view of the assembly which explains the sequence 0 figure 11,fixed Frame (2) is excluded for ease of showing the mechanism parts. The operation starts by pulling the Handle (11) up, this operation makes the hollow pin (12) to travel in cam slot and push the contacts to disengage and moves the draw-out relay (3) out of the Pin Rail (6). Now the Draw-out relay (2) unit is ready to pull out of the Fixed Frame (2) to completely remove the relay unit. No provision to pull the Draw-out relay is provided other than Handle (11) this avoids unintentional removal. Again in all rack-out operation only the cam operating force will be transferred independently of the operator’s force of operation for the contact disengagement.

Some of the benefits of the present invention, considered to be noteworthy are mentioned below:

[1]. Controlled contact engagement improves contact life.

[2]. Combined handle and the mechanism actuator minimizes number of components.

[3]. Locks contact in on condition and avoid un-intentional removal.