Title of Invention

SHROUD MECHANISM FOR OVERLOAD RELAYS

Abstract

Shroud mechanism for overload relay adapted for providing full access to the terminals and the terminal screws (9) and comprises means adapted for providing swivel motion to the shroud (1) resting on the housing (2), means (7 and 8) adapted for snap fitting of the shroud (1) with the said housing (2) and plurality of holes (4) having defined configuration for accessing the terminal and the terminal screws (9) of the relay.

Full Text

FORM2 THE PATENTS ACT, 1970 (39 of 1970) & The Patents Rules, 2003 COMPLETE SPECIFICATION (See section 10; rule 13) 1. Title of the invention. - SHROUD MECHANISM FOR OVERLOAD RELAYS 2. Applicant(a) NAME: LARSEN&TOUBROLIMITED(b) NATIONALITY: 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: Field of the invention The present invention relates shroud mechanism for overload relay. More particularly, it relates to overload relay shroud mechanism adapted for giving full access to the terminals and the terminal screws, hence facilitating easy termination of cables with least force requirement and simultaneously complying with the standard finger proofing norms. Background Art Traditionally, the shroud of the overload relays is fixed firmly to the housings of the relay or the shroud is click fitted with the said housings. In case the shroud is fixed firmly to the relay housing, when the user has to access the terminals, he has limited access to the terminals because of limited diameter of the holes in the shroud. When the shroud is click fitted to the relay housings when the user needs to open the shroud to get full access of terminals. He may do so but it is not guaranteed that the user will put back the shroud in which case the finger proofing (safety) norm is defeated. Also it is possible that the click fit arrangement may get damaged while defeating as the click fit is a fragile part of shroud, which will result into non- compliance of finger proofing norms. At the same time the terminal inspection is difficult when the relay is in operation, as the shroud click-fit needs to be defeated. AT404752B teaches an attachment for a shroud to a housing, in which the shroud and the housing can be engaged with one another by means of a pin and a depression which holds this pin, in which case a lock which is at a distance from these items is provided by means of a screw that engages in a threaded hole. In order to allow simple locking, the invention provides that the screw is held in a drilled-through plug, in which case the head of the 2 screw is held such that it can move axially between a shoulder of the hole of the plug and a constriction in that section of the hole which has the larger diameter, which exceeds the diameter of the head of the screw. JP2001319707 teaches an assembled body consisting of an insulation frame, a terminal screw on the power supply side allocated and fitted on the insulation frame, clamp terminal fittings on the load side, a connecting plate to connect the clamp terminal fittings and the terminal screws, a terminal cover on the load side which, covering the clamp terminal fittings and the terminal screws, adheres to the insulation frame, and the terminal cover on the power supply side. In the relay terminal board wherein the terminal screws are connected to the load side terminals of the circuit breaker for wiring and in which wire terminals on the load side are inserted/connected to the clamp terminal fittings, the terminal cover on the load side and the terminal cover on the power supply side are made to be independent parts and support arms installed at each terminal cover are hinged with a pair of left and right support columns erecting from the center of the insulation frame and supported capable of opening/closing independently. Generally, many of the switchgear/overload relay failures/damages are attributed to improper terminations. The present inventors have now found that shroud adapted for click fit and provided with hinges takes care of the safety norms and provide full access to the terminals when opened fully, thereby providing proper terminations of the phase terminals minimizing chance of overload relay failures/damages. The shroud being provided with holes with defined configuration adapted to access the terminal screws without opening the shroud. The present inventors have also found that the hinges holding the shroud with some restricted movement gives full access to the terminals and terminal screws, which has not been found in the above prior art. With this arrangement the terminal can be inspected easily. 3 Objects of the Invention The basic object of the present invention is to provide full access to the phase terminals of the conductors simultaneously complying with the standard finger-proofing norms. Another object is to facilitate use of fasteners wherein the force required to tighten the terminations of the conductor phases for same torque is less than the traditional screw-washers used in similar kind of devices. The other object is to facilitate the terminal inspection at any point of time in a simple way. Summary of the Invention Thus according to the main aspect of the present invention there is provided a shroud mechanism for overload relay, the said shroud mechanism adapted for providing full access to the terminals and the terminal screws, the said shroud mechanism comprising: (i) means adapted for providing swivel motion to the shroud resting on the housing; (ii) means adapted for snap fitting of the shroud with the said housing and; (iii) plurality of holes having defined configuration for accessing the terminal and the terminal screws of the relay. Detailed Description Of The Invention In the present invention, the housing of the overload relay comprises the terminal shroud. The shroud comprises means for producing swivel motion to the shroud. The said means comprises hinge located on the two ends of the bottom housing of the overload relay such that the shroud can be 4 swiveled about the axis on which it is hinged. The said hinge holding the shroud on the bottom housing comprises fixed degree of freedom adapted for providing restricted swivel movement of the shroud about the axis of the hinge, locating the shroud in a position and achieving full access to the terminals and terminal screws. The bottom housing of the overload relay comprises certain profiles adapted for the said restricted swivel movement of the shroud. The hinge is provided with fixed degree of freedom such that when the shroud is opened fully there is full access to the terminals, thereby allowing entry of bigger sized screw drivers inside the housing for tightening the terminals and terminal screws with minimum force. The shroud of the present invention comprises means for snap fitting the shroud on the housing of the relay. The said means comprises protrusion provided on the upper part of the shroud such that on applying downward force on the said protrusion of the shroud, the shroud can be opened with a swivel motion about the axis on which it is hinged. The above arrangement of the shroud, protrusion and the hinge being adapted for flip-opening the shroud and full access of the phase terminals and terminal screws of the overload relay, which are connected to the cable and cable lugs and allow use of bigger sized screwdrivers for tightening the terminal screws. The protrusion of the shroud being such that it just fits into the groove provided in the housing of the relay adapted for proper latching of the shroud when it is put back complying with the standard finger-proofing norm. The shroud comprises plurality of holes, which are provided in the shroud having definite superficial location adapted for accessing the phase terminals and terminal screws keeping the shroud closed. The holes being placed on the surface of the shroud such that the holes are exactly above the terminal screw heads and the diameters of the holes are decided by the 5 distance between the surface of the screw and the surface of the shroud. The plurality of holes comprising holes of definite diameter being the integral part of the shroud moves along with the swivel movement of the shroud to differential positions and adapted for accessing the terminals and terminal screws. Brief Description Of The Accompanying Figures Figure 1 illustrates the shroud mechanism of the present invention in closed condition. Figure 2 illustrates the opened hinged shroud in the present invention. Figure 3 illustrates the front view of the hinged shroud in open condition. Detailed Description Of The Accompanying Figures In figure 1 the shroud mechanism of the present invention in closed condition is illustrated. The hinged shroud (1) is mounted on the housing (2) of the overload relay. The shroud (1) is hinged at the pivot point (3) and comprises holes (4) for phases of terminals of the relay, which are connected to the cable lugs (5) and cables (6). In the figure the protrusion (7) of the shroud (1) is such that it just fits into the groove (8) provided in the housing (2). In figure 2 the opened hinged shroud of the present invention is illustrated. The hinged shroud (1) though in open condition gives clear access to the cable lugs (5) and cables (6) from the bottom side of the mechanism. With the shroud (1) in the open condition simultaneously access of the cable lugs (5) and cables (6) from the bottom side and frontal access of the terminal screws (9) (shown in figure 3) can be made. 6 We Claim:- 1. A shroud mechanism for overload relay, the said shroud mechanism adapted for providing full access to the terminals and the terminal screws, the said shroud mechanism comprising: (i) means adapted for providing swivel motion to the shroud resting on the housing; (ii) means adapted for snap fitting of the shroud with the said housing and; (iii) plurality of holes having defined configuration for accessing the terminal and the terminal screws of the relay. 2. Shroud mechanism as claimed in claim 1, wherein the means adapted for providing swivel motion to the shroud comprises hinges on the two ends of the bottom housing of the relay. 3. Shroud mechanism as claimed in claim 2, wherein the said hinge comprises fixed degree of freedom adapted for providing restricted swivel movement of the shroud about the axis of the hinge and locating the shroud in a position to achieve full access to the terminals and terminal screws. 4. Shroud mechanism as claimed in claim 3, wherein the hinge is provided with fixed degree of freedom such that when the shroud is opened fully, there is full access to the terminals and even bigger sized screw drivers are adapted for tightening the terminals and terminal screws with minimum force. 7 5. Shroud mechanism as claimed in claim 1, wherein the means adapted for snap fitting the shroud to the housing comprises protrusions provided on the upper part of the shroud and adapted for opening the shroud applying downward force on it. 6. Shroud mechanism as claimed in claim 5, wherein the protrusions being such that it just fits into the groove provided in the housing of the relay adapted for proper latching complying with the standard finger-proofing norm. 7. Shroud mechanism as claimed in claim 1, wherein the plurality of holes being placed on the surface of the shroud forming an integral part of it, move alongwith the swivel movement of the shroud to differential positions and adapted for accessing the terminals and terminal screws. 8. Shroud mechanism as claimed in claim 9, wherein the shroud positioning adapted for full access of the terminal and the terminal screws. 9. Shroud mechanism substantially as herein described and illustrated with reference to the accompanying figures. Dated this 20 th day of May, 2005. Dr. Sanchita Ganguli of S. Majumdar & Co. Applicant's agent 8 ABSTRACT Title : Shroud Mechanism For Overload Relays Shroud mechanism for overload relay adapted for providing full access to the terminals and the terminal screws (9) and comprises means adapted for providing swivel motion to the shroud (1) resting on the housing (2), means (7 and 8) adapted for snap fitting of the shroud (1) with the said housing (2) and plurality of holes (4) having defined configuration for accessing the terminal and the terminal screws (9) of the relay. Figure 1

Documents:

633-mum-2005- claim.doc

633-mum-2005-abstract(25-5-2005).pdf

633-MUM-2005-ABSTRACT(26-3-2014).pdf

633-mum-2005-abstract.doc

633-MUM-2005-ANNEXURE TO FORM 3(3-10-2011).pdf

633-MUM-2005-CHINESE DOCUMENT(3-10-2011).pdf

633-MUM-2005-CLAIMS(AMENDED)-(26-3-2014).pdf

633-MUM-2005-CLAIMS(AMENDED)-(8-11-2011).pdf

633-MUM-2005-CLAIMS(MARKED COPY)-(26-3-2014).pdf

633-mum-2005-claims.pdf

633-mum-2005-correspondence received-ver-02-07-2005.pdf

633-mum-2005-correspondence received-ver-20-05-2005.pdf

633-mum-2005-correspondence received.pdf

633-MUM-2005-CORRESPONDENCE(12-6-2012).pdf

633-MUM-2005-CORRESPONDENCE(13-1-2014).pdf

633-MUM-2005-CORRESPONDENCE(15-5-2013).pdf

633-MUM-2005-CORRESPONDENCE(16-4-2009).pdf

633-MUM-2005-CORRESPONDENCE(18-2-2014).pdf

633-MUM-2005-CORRESPONDENCE(21-8-2012).pdf

633-MUM-2005-CORRESPONDENCE(22-2-2010).pdf

633-mum-2005-correspondence(25-9-2009).pdf

633-MUM-2005-CORRESPONDENCE(26-7-2010).pdf

633-MUM-2005-CORRESPONDENCE(7-2-2011).pdf

633-mum-2005-description (complete).pdf

633-mum-2005-description(complete)-(25-5-2005).pdf

633-MUM-2005-DRAWING(26-3-2014).pdf

633-mum-2005-drawings.pdf

633-mum-2005-form 1(8-7-2005).pdf

633-mum-2005-form 18(17-9-2007).pdf

633-mum-2005-form 2(25-5-2005).pdf

633-mum-2005-form 2(title page)-(25-5-2005).pdf

633-MUM-2005-FORM 3(26-3-2014).pdf

633-mum-2005-form-1.pdf

633-mum-2005-form-2.doc

633-mum-2005-form-2.pdf

633-mum-2005-form-26.pdf

633-mum-2005-form-3.pdf

633-MUM-2005-PETITION UNDER RULE 137(26-3-2014).pdf

633-MUM-2005-POWER OF ATTORNEY(26-3-2014).pdf

633-MUM-2005-REPLY TO EXAMINATION REPORT(3-10-2011).pdf

633-MUM-2005-REPLY TO EXAMINATION REPORT(8-11-2011).pdf

633-MUM-2005-REPLY TO HEARING(26-3-2014).pdf

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