Claims:1. A safety interlock mechanism for a feeder, the mechanism comprising:
A slider configured to slide between a first position and a second position, wherein when the slider is in the first position, access to a racking screw is blocked and when the slider is in the second position access to the racking screw is available;
a handle for actuating a short circuit protection device (SCPD between an ON position and an OFF position,
a lever operatively coupled to the handle such that it blocks movement of the slider out of the first position when the SCPD is in ON position thus blocking access to the racking screw.
.
2. The mechanism of claim 1, wherein the lever does not block the movement of the slider out of the first position when the SCPD is in OFF position thus allowing access to the racking screw.

3. The mechanism of claim 1, wherein the slider has a shape similar to Roman numeral ’1’.

4. The mechanism of claim 1, wherein the slider incorporates a curved profile and when the handle is in ON position the lever engages with the curved profile to prevent movement of the slider to the second position.

5. The mechanism of claim 1, wherein the slider further incorporates at least one elongated hole and the slider is slidably secured to a mechanism plate by at least one screw through the al least one elongated hole.

6. The mechanism of claim 4, wherein the curved profile maintains a gap with the lever to avoid friction during movement of the lever when the SCPD trips.

7. The mechanism of claim 1, wherein the slider moves from the second position to the first position under its weight.

8. The mechanism of claim 7, wherein the slider further incorporates a flange configured to add weight to the slider.

9. The mechanism of claim 1, wherein the lever comprises at least one extended projection that engages with the curved profile of the slider.

10. The mechanism of claim 1, wherein the slider does not move to the first position when operating handle of the racking screw is in position thus preventing actuation of the handle to ON position. , Description:TECHNICAL FIELD
[0001] The present disclosure relates to the field of low voltage power distribution systems. In particular it pertains to a safety interlock mechanism in Short Circuit Protection Devices (SCPD).

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Typically two types of switchboards are used in power distribution systems, namely Power Control Centre (PCC) and Motor Control Centre (MCC). Power Control Centre (PCC) distributes the received power to different Motor Control Centres (MCC) while Motor Control Centres (MCC) distribute the power intelligently to different motor loads, lamp loads using feeders/modules.
[0004] Typically each MCC panel has a number of feeders which comprise of SCPDs, monitoring relays and controlling devices. The feeders may be draw out type and fixed type. Fixed type feeders are fixed in the compartment whereas a Draw out type feeder is removable and it has three stages of operation while racking in: isolate, test and service. In isolate stage of a SCPD, Power & control circuit both will be off. The test stage has only control supply whereas in service stage both power and control supply is ON.
[0005] From safety point of view, it should not be possible to rack in and rack out the feeder when the SCPD is in ON condition. The requirement is met by providing safety interlock between the SCPD and racking system of the feeder. In conventional arrangements,
handle to operate the SCPD is mounted on door and safety feature is inherent part of handle itself. Access to racking screw is not possible until door is opened and door of feeder can be opened only when the SCPD is OFF.
[0006] However, in certain applications there is a requirement that SCPD handle should not be part of the door so that the SCPD may be operated in test condition or during maintenance. However, if SCPD handle is not made part of the door, other safety requirements would be impaired during operation of the feeder. In order to overcome such impairment there is a requirement of a new safety interlock system which provides interlock in a better and more efficient way.
[0007] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[0008] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[0009] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0010] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0011] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims.

OBJECTS OF THE INVENTION
[0012] A general object of the present disclosure is to provide a safety interlock between SCPD and racking screw of feeder.
[0013] An object of the present disclosure is to provide an interlock mechanism that does not allow racking operation when the SCPD is in ON position.
[0014] An object of the present disclosure is to provide an interlock mechanism for a configuration in which SCPD handle is not part of door.
[0015] Another object of the present disclosure is to ensure that safety is maintained even if door is open and SCPD is on.
[0016] Another object of the present disclosure is to provide an interlock mechanism that does not allow access to racking screw even if door is opened.
[0017] Yet another object of the present disclosure is to provide an interlock mechanism that restricts access to racking screw of the feeder when the SCPD is ON.
[0018] Yet another object of the present disclosure is to provide an interlock mechanism that does not allow the SCPD to be put ON if operating handle for the racking screw is in position.
[0019] Still another object of the present disclosure is to provide an interlock mechanism that does not use any cord/cable and spring for interlocking action.

SUMMARY
[0020] Aspects of the present disclosure relate to a safety interlock mechanism in feeders of MCCs. In an aspect, the disclosure provides an interlock mechanism that does not allow the feeder to be racked if SCPD of the feeder is in ON condition.
[0021] In an aspect, the interlock that prevents racking operation when the feeder is in ON condition is based on blocking access to racking screw of the feeder.
[0022] In an aspect, the access to the racking screw is blocked by a slider that can take two different positions such as a first position and a second position. The slider, in its first position can block access to the racking screw of the feeder but allow access to the racking screw of the feeder in its second position.
[0023] In an aspect, the slider can be prevented from movement from its first position to its second position when the SCPD is in ON position. Thus the slider blocks any effort to gain access to the racking screw of the feeder thereby providing a safety interlock.
[0024] In an embodiment, mean to prevent the movement of the slider from its first position to its second position when the SCPD is in ON position is a lever that is operatively coupled to actuation handle of the SCPD. In an aspect, when the handle is in ON position, the lever takes a position that prevents sliding motion of the slider from its first position to its second position. Alternatively, when the handle is in OFF position, the lever takes a position that allows sliding motion of the slider from its first position to its second position thereby allowing sliding of the slider for access to the racking screw.
[0025] In an embodiment, the slider can be shaped like Roman numeral “1” wherein the lever can engage with the curved surface of the Roman numeral “1” on top side when the handle is in ON condition thereby preventing slider’s movement in upward direction. In an embodiment, the upward movement of the slider results in access to the racking screw that is covered by lower part of the slider. In an alternate embodiment, the lever can be away from the curved surface of the Roman numeral “1” when the handle is in ON condition thereby allowing upward sliding of the slider for access to the racking screw.
[0026] In an embodiment, the molded lever can be in engagement with shaft of the handle such that when the handle is moved between ON position and OFF position, the molded lever too moves between position of engagement with the curved surface of the slider and that of non-engagement respectively.
[0027] In an aspect, the slider is disclosed mechanism does not affect functioning of other mechanisms of the feeder. Further, the disclosed mechanism is compact and requires very little space.
[0028] In yet another aspect, the interlock mechanism works without any spring which reduces undesired complexity of the arrangement. It also does not depend on any cord/cable for its operation. The proposed disclosure uses cam-follower and gravity based system for safety interlocking and elimination of complex spring and cord/cable based mechanism results in a more robust, reliable and compact system.
[0029] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components

BRIEF DESCRIPTION OF THE DRAWINGS
[0030] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0031] FIG. 1 illustrates an exemplary perspective view of feeder in accordance with an embodiment of the present disclosure.
[0032] FIG. 2 illustrates an exemplary perspective view of slider for safety interlocking the feeder in accordance with an embodiment of the present disclosure.
[0033] FIG. 3 illustrates an exemplary perspective view of the interlock mechanism installed in the feeder in accordance with an embodiment of the present disclosure.
[0034] FIG. 4 illustrates an exemplary perspective view indicating general position of the slider and lever in accordance with an embodiment of the present disclosure.
[0035] FIG. 5 illustrates an exemplary perspective view indicating position of the slider and the lever in SCPD ON position in accordance with an embodiment of the present disclosure.
[0036] FIG. 6 illustrates an exemplary perspective view indicating the slider in engagement with extended projection of the lever in accordance with an embodiment of the present disclosure.
[0037] FIG. 7A and 7B illustrate exemplary perspective views in two different directions showing position of the slider and the lever in SCPD OFF condition in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0038] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0039] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[0040] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0041] Embodiments of the present disclosure relate to a safety interlock mechanism in feeders of MCCs. In an aspect, the disclosure provides an interlock mechanism that does not allow the feeder to be racked if SCPD of the feeder is in ON condition by blocking access to racking screw of the feeder
[0042] In an embodiment, the access to the racking screw is blocked by a slider that can be slid to gain access the racking screw. The sliding of the slider can be enabled when the SCPD is in OFF condition but blocked when the SCPD is in ON condition.
[0043] In an embodiment, the sliding of the slider in ON position of the SCPD can be prevented by a lever. The lever can be operatively coupled to actuation handle of the SCPD such that when the handle is in ON position, the lever prevents sliding of the slider preventing access to the racking screw. And when the handle is in OFF position, the lever allows sliding of the slider for access to the racking screw.
[0044] Referring now to FIG. 1 wherein an exemplary perspective view100 of the feeder is shown. As shown, the feeder can comprise a SCPD 102 and its actuating handle 104. The feeder can be racked by means of a racking screw 110. In accordance with the present disclosure, access to the racking screw can be blocked by a slider 108 that can cover the opening in the front plate 106 of the module that provides access the racking screw 110. In an embodiment, when the access to the racking screw is to be gained, the slider can be slid up and racking screw turned for racking the feeder.
[0045] Thus, when the slider 108 is in lower position (i.e. first position) the access to the racking screw is blocked. For gaining access to the racking screw 110 the slider has to be lifted up to a second position in which the racking screw becomes accessible for operation.
[0046] In an embodiment, the slider can be prevented from movement from its first position to its second position when the SCPD 102 is in ON position blocking any effort to gain access to the racking screw 110. Thus, the required safety interlock in the feeder cam be achieved by preventing sliding movement of the slider 108 when the SCPD 102 is in ON condition.
[0047] FIG. 2 illustrates an exemplary perspective view200 of the slider for safety interlocking the feeder in accordance with an embodiment of the present disclosure. As shown, the slider 108 can be shaped like Roman numeral ‘1’. The slider 108 can incorporate several features such as a curved profile 202, elongated holes 204 and a flange 206. In an embodiment, the slider 108 can be slidably configured by means of threaded screws through the elongated holes 204. The curved surface 202 is configured the engage with a lever (not shown here) that blocks upward sliding motion of the slider 108. The flange can add weight to the slider so that it falls down to its first position and block access to the racking screw under its own weight without any external aid.
[0048] FIG. 3 illustrates an exemplary perspective view 300 of the installed interlock mechanism in accordance with an embodiment of the present disclosure. Shown therein is position of the slider 108 in relation with shaft of the handle 104. It also depicts slidable mounting of the slider 108 on the safety mechanism plate 302by means of two screws 306 through the elongated holes 204.
[0049] FIG. 4 illustrates an exemplary perspective view 400 indicating general position of the slider and lever in accordance with an embodiment of the present disclosure. As shown, a lever 402 in engagement with the shaft 304can be configured to prevent upward sliding motion of the slider 108. The lever 402 can engage with the curved surface 202 of the slider 108 in order to block/prevent upward sliding motion of the slider 108 in from the first position to the second position.
[0050] In an embodiment, the lever 402 can rotate along with the shaft 304 as the handle 104 is rotated to move the SCPD 102 between ON and OFF positions and block sliding movement of the slider 108 by engaging at curved profile 202 when the SCPD 102 is in ON condition. Alternatively, when the SCPD 102 is in OFF condition, the lever 402 is clear off the curved profile 202 so that it does not engage with the block the curved profile 202 and thus allows the sliding motion of the slider 108.
[0051] In an embodiment, the curved profile 202 can be designed in such a manner that it does not allow the slider 108 to move up until lever 402 is completely attains OFF position of the SCPD 102. It further ensures sufficient gap between the lever 402 and the slider 108 when the slider is in the first position to avoid any friction between the two during occurrence of TRIP in the SCPD 102.
[0052] FIG. 5 illustrates an exemplary front view 500 indicating position of the slider 108 and the lever402 in ON position of the SCPD 102 in accordance with an embodiment of the present disclosure. Shown therein is position with the lever 402 blocking sliding motion of the slider 108 preventing its movement to the second position for gaining access to the racking screw..
[0053] FIG. 6 illustrates an exemplary perspective view indicating the slider in engagement with extended projection of the lever in accordance with an embodiment of the present disclosure. As shown the lever 402 can be mounted on the shaft 304 through a cut out such as a square hole 604 matching shape of the shaft 304 to ensure rotable engagement between the two. The lever 402 can further incorporate an extended projection 602 that moves over the curved profile 202 of the slider 108 when the lever 402 rotates along with the handle 104 and shaft 304 for changing the status of the SCPD 102.
[0054] FIG. 7A and 7B illustrate exemplary perspective views 700 and 750 from two different directions showing position of the slider and the lever in SCPD OFF condition wherein they show that when the SCPD 102 is in OFF condition, the lever 402 is clear off the curved profile 202 of the slider 108 and thus it cannot obstruct upward movement of the slider to the second position. As stated earlier, shifting the slider 108 to the second position can provide access to the racking screw 110.
[0055] In an embodiment, if operating handle for the racking screw (not shown)is not removed, the slider 108 cannot move down under its own weight and shall remain in the second position. The slider 108 remaining in the second position shall not allow the handle 104 or the shaft 304 to be rotated as the lever 402 shall be obstructed by the slider 108. Thus the SCPD 102 cannot be actuated to ON condition.
[0056] As can be seen, the proposed mechanism does not use a cord or cable as in conventional interlock mechanisms. Furthermore, interlocking is provided using a cam follower arrangement. Furthermore, gravity based interlocking is provided, which eliminates complicated spring arrangement. Furthermore, the proposed disclosure has lesser number of moving parts, which can result in better mechanical life, a compact configuration and better reliability.
[0057] In an aspect, the cord-less safety interlock mechanism provides ease of maintenance due to independent assembly for the slider 108 and the lever 402 which makes the mechanism simple. Locking system with no direct connection of slider and rotating shaft reduces friction and also ensures error free and failure free operation specially during tripping of the SCPD 102.
[0058] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.
[0059] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[0060] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0061] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.

ADVANTAGES OF THE INVENTION
[0062] The present disclosure provides a safety interlock between SCPD and racking screw of feeder.
[0063] The present disclosure provides an interlock mechanism that does not allow racking operation when the SCPD is in ON position.
[0064] The present disclosure provides an interlock mechanism for a configuration in which SCPD handle is not part of door.
[0065] The present disclosure ensures that safety is maintained even if door is open and SCPD is on.
[0066] The present disclosure provides an interlock mechanism that does not allow access to racking screw even if door is opened.
[0067] The present disclosure provides an interlock mechanism that restricts access to racking screw of the feeder when the SCPD is ON.
[0068] The present disclosure provides an interlock mechanism that does not allow the SCPD to be put ON if operating handle for the racking screw is in position.
[0069] The present disclosure provides an interlock mechanism that does not use any cord/cable and spring for interlocking action.