Claims:1. A mechanism for interlocking plugging-in/plugging-out of a plug-in unit from a busway with ON/OFF condition of its MCCB, the mechanism comprising:
at least one latch mechanism operatively coupled to a handle that actuates the MCCB between ON and OFF conditions;
at least one linear lock mechanism incorporating an interlock pin configured to slide in and slide out, wherein actuation of the at least one linear lock mechanism results in the interlock pin to slide out; and
at least one busway latch mechanism incorporating a latch configured to latch the plug-in unit to the busway when the latch is pushed in, wherein the latch incorporates a hole that is in alignment with the interlock pin when the latch is pushed in to latch the plug-in unit to the busway;
wherein, when the handle is moved to ON condition, it actuates the at least one linear lock mechanism to result in the interlock pin to move out and engage with the hole in the latch and prevent its movement out of the pushed in position.
2. The mechanism of claim 1, wherein the interlock pin is biased by a spring to remain in withdrawn condition.
3. The mechanism of claim 2, wherein the interlock pin in its withdrawn condition is not in engagement with the hole in the latch thus allowing the latch to be pulled out to unlatch the plug-in unit.
4. The mechanism of claim 2, wherein the at least one linear lock mechanism incorporates a linear cam configured to engage with the at least one latch mechanism when the handle is moved to ON position and cause the interlock pin to move out from its withdrawn condition overcoming the biasing force of the spring.
5. The mechanism of claim 2, wherein when the handle is moved to OFF position the latch mechanism withdraws to allow the linear cam and the interlock pin to return to the withdrawn position under the biasing force of the spring.
6. The mechanism of claim 1, wherein the latch is biased by a spring to remain in pushed-in position.
7. The mechanism of claim 1, wherein the at least one busway latch mechanism further incorporates a latch actuator configured to pull the latch out.
8. The mechanism of claim 7, wherein the at least one busway latch mechanism further incorporates a latch base and the latch actuator is pivotally fixed to the latch base.
9. The mechanism of claim 1, wherein the at least one busway latch mechanism further incorporates a latch extension, wherein the latch extension is fixed to the latch.
10. The mechanismof claim 8, wherein the latch actuator engages with the latch extension to pull the latch out.
, Description:TECHNICAL FIELD
[0001] The present disclosure relates to the field of low voltage power distribution systems. In particular it pertains to interlocking of a plug in unit with a busway so that it cannot be assembled or dismantled on/from the busway when corresponding MCCB is in an ON condition.
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] In low voltage power distribution systems, plug-in concept is used in busway installations to minimize field installation work. Plug-in units are used as a means to tap power from main conductors in busways. Using plug-in units concept, expanding a circuit becomes much less of a hassle and safer as it eliminates field wire cutting and terminating branch circuits.
[0004] A plug-in unit typically incorporates a short-circuit protection device like a Moulded Case Circuit Breaker (MCCB) placed inside of plug-in box, and power is derived through the plug-in box depending on the parity of the device viz. On, Off, Trip. The plug-in boxes can be tapped into the busway manually. The plug-in boxes may be accessible to unauthorized personnel who can unplug the boxes If the plug-in box is pulled out of its position in a live condition a hazardous condition is created where short-circuit is possible between the contacts due to an increased space. It can also create a situation where the power fed to the downstream device is cut-off leading to an unwanted power disruption.
[0005] There is therefore a need of an interlocking means to lock the position of the plug-in unit with respect to the busway such that it remains plugged with the busway as long as the its MCCB is in an ON condition.
[0006] 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.
[0007] 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.
[0008] 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.
[0009] 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.
[0010] 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
[0011] A general object of the present disclosure is to provide a locking mechanism for locking plug-in units with busways that ensures safety of operation.
[0012] An object of the present disclosure is to provide a locking mechanism for locking plug-in units with busways that incorporates an interlocking with switching mechanism.
[0013] Another object of the present disclosure is to provide an interlocking mechanism that does not allow the plug-in unit to be unplugged from the busway as long as its MCCB is in an ON condition.
[0014] Yet another object of the present disclosure is to provide an interlocking mechanism that does not allow the plug-in unit to be put ON unless the plug-in unit is locked to the busway.
[0015] Still another object of the present disclosure is to provide an interlocking mechanism that does not allow the plug-in unit to be plugged-in to the busway if the plug-in unit is in ON condition.

SUMMARY
[0016] Aspects of the present disclosure relate to a locking mechanism for locking plug-in units with busways that incorporates an interlocking with switching mechanism. In particular, the present disclosure provides an interlocking mechanism that does not allow the plug-in unit to be unplugged from the busway as long as its MCCB is in an ON condition. And at the same time does not allow the plug-in unit to be put ON unless the plug-in unit is locked to the busway.
[0017] In an aspect, the interlocking mechanism can incorporate at least one latch mechanism, at least one linear lock mechanism and at least one busway latch mechanism. The at least one busway latch mechanism can be fixed on the plug-in unit and configured to latch the plug-in unit to the busway. The latching can be affected by sliding movement of a latch wherein pushing the latch IN can result in its engagement with the busway thereby latching the plug-in unit to the busway. When the plug-in unit is to be unplugged, the latch can be pulled out to disengage it from the busway.
[0018] In an aspect, interlocking of plugging/unplugging action of the plug-in unit with switching of the MCCB of the plug-in unit can be achieved by preventing sliding movement of the latch of the busway latch mechanism when the MCCB of the plug-in box is in ON position. Inability of the latch to slide out when the MCCB is ON does not allow the plug-in unit to be unplugged from the busway thus meeting the desired requirement.
[0019] In an aspect, the linear lock mechanism is configured to prevents liding movement of the latch of the busway latch mechanism when the MCCB of the plug-in box is in ON position. The linear lock mechanism can incorporate a linearly travelling interlock pin that engages in a corresponding hole in the latch of the busway latch mechanism to prevent sliding movement of the latch. In an aspect, the linearly travelling pin can travel to engage with the hole in the latch when the MCCB/plug-in box is put ON.
[0020] In an alternative situation, if the plug-in box is not latched to the busway i.e. the latch is not pushed in, the Hole in the latch can be out of alignment from the interlock pin which can prevent full linear travel of the interlock pin and consequently inability to put the MCCB in ON condition.
[0021] In yet another alternative situation, if the plug-in box is in ON position before plugging in, the latch cannot be pulled out due to engagement of the interlock pin in the hole of the latch. As pulling out of the latch 252 is prerequisite for positioning of the plug-in unit on the busway, the plug-in unit cannot be plugged in to the busway.
[0022] In an aspect, the latch mechanism can be operatively coupled to handle that actuates the MCCB of the plug-in unit between ON and OFF positions, and incorporate a cam that, on actuation of the handle from OFF to ON position, causes linear travel in the interlock pin to engage with the corresponding hole in the latch thereby preventing its sliding movement. In an alternate scenario, when the handle is actuated from ON to OFF position, the cam can withdraw and allow retraction of the interlock pin under force of a spring to disengage from the hole in the latch thereby allowing the latch to be pulled out to enable unplugging of the plug-in unit from the busway.
[0023] Thus the disclosed interlock mechanism comprising at least one latch mechanism, at least one linear lock mechanism and at least one busway latch mechanism can provide the desired interlock between plugging/unplugging of the plug-in unit and ON/OFF status of the unit.
[0024] 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
[0025] 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.
[0026] FIG. 1illustrates an exemplary schematic view of a plug-in unit with busway latching mechanism and a busway in accordance with embodiments of the present disclosure.
[0027] FIG. 2A and 2B illustrate exemplary schematic views of a plug-in unit indicating details of interlock mechanism in accordance with embodiments of the present disclosure.
[0028] FIG. 3A to 3C illustrate exemplary schematic views showing further details of working of the interlock mechanism in accordance with an embodiment of the present disclosure.
[0029] FIG. 4A and 4B illustrate exemplary isometric and exploded views respectively of busway latch mechanism in accordance with an embodiment of the present disclosure.
[0030] FIG. 5A and 5B illustrate exemplary isometric and exploded views respectively of linear lock mechanism in accordance with an embodiment of the present disclosure.
[0031] FIG. 6A and 6B illustrate exemplary isometric and exploded views respectively of latch mechanism in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0032] 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.
[0033] 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.
[0034] 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.
[0035] Aspects of the present disclosure relate to an interlocking mechanism that provides desired interlock between plugging/unplugging of the plug-in unit and ON/OFF status of the unit. The disclosed mechanism does not allow the plug-in unit to be unplugged from the busway as long as MCCB/plug-in unit is in an ON condition. At the same time, the disclosed mechanism does not allow the plug-in unit to be put ON unless the plug-in unit is properly latched to the busway or does not allow the plug-in unit to be plugged in to the busway in ON condition.
[0036] In an aspect, the interlocking mechanism can incorporate at least one latch mechanism, at least one linear lock mechanism and at least one busway latch mechanism. The at least one busway latch mechanism can be fixed on the plug-in unit and configured to latch the plug-in unit to the busway. Each of the at least one busway latch mechanism can incorporate a latch configured to latch the plug-in unit to the busway by its sliding action. The latching can be affected by pushing in the latch that can result in its engagement with the busway thereby latching the plug-in unit to the busway. When the plug-in unit is to be unplugged, the latch can be pulled out to disengage it from the busway.
[0037] In an aspect, interlocking of plugging/unplugging action of the plug-in unit with switching of the MCCB of the plug-in unit can be achieved by preventing sliding movement of the latch of the busway latch mechanism when the MCCB of the plug-in box is in ON position. Inability of the sliding plate to slide out when the MCCB is ON does not allow the plug-in unit to be unplugged from the busway in its ON condition.
[0038] In an aspect, the linear lock mechanism is configured to prevents liding movement of the latch of the busway latch mechanism when the MCCB of the plug-in box is in ON position. The linear lock mechanism can incorporate a linearly travelling interlock pin that engages in a corresponding hole in the latch of the busway latch mechanism to prevent sliding movement of the latch. In an aspect, the hole in the latch and the interlock pin can be in alignment when the latch is in pushed in condition. The interlock pin can travel as the MCCB/plug-in box is put ON and engage with the hole in the latch.
[0039] In an alternative situation, if the plug-in box is not latched to the busway i.e. the latch is not pushed in, the Hole in the latch can be out of alignment from the interlock pin which can prevent linear travel of the interlock pin and consequently inability to put the MCCB in ON condition.
[0040] In an aspect, the plug-in unit can be put ON only when the hole in the latch and the interlock pin are aligned i.e. the latch is in pushed in condition. Therefore, if the plug-in box is in ON position before plugging in, the latch cannot be pulled out due to engagement of the interlock pin in the hole of the latch. As pulling out of the latch is prerequisite for positioning of the plug-in unit on the busway, the plug-in unit cannot be plugged in to the busway.
[0041] In an aspect, the latch mechanism can be operatively coupled to handle that actuates the MCCB of the plug-in unit between ON and OFF positions, and incorporate a cam that, on actuation of the handle from OFF to ON position, causes linear travel in the interlock pin to engage with the corresponding hole in the latch thereby preventing its sliding movement. In an alternate scenario, when the handle is actuated from ON to OFF position, the cam can withdraw and allow retraction of the interlock pin under force of a spring to disengage from the hole in the latch thereby allowing the latch to be pulled out to enable unplugging of the plug-in unit from the busway.
[0042] Referring to FIG. 1, wherein a plug-in unit 102 with busway latching mechanism 104 and a busway 106 are shown. The latching mechanism 104 can be fixed to the plug-in unit 102 and there can be two of them one on either side as shown in FIG. 1 to provide proper latching. The plug-in unit 102 can be positioned in appropriate position after pulling out the latch extensions 108. The latch extensions 108 can be pulled out by suitable means (to be described later) that can also help to release them to enable them to move back after proper positioning of the plug-in unit 102 on the busway 106. Releasing the latch extensions can latch the plug-in unit 102 to the busway 106 (the busway latch mechanism 104 to be further explained in subsequent paragraphs).
[0043] FIG. 2A and 2B illustrate exemplary schematic views of a plug-in unit indicating details of interlock mechanism in accordance with embodiments of the present disclosure. FIG. 2A shows the plug-in unit with internal details that, besides other things, incorporate at least one latch mechanism 202, at least one linear lock mechanism 204 and at least one busway latch mechanism 104.The latch mechanism 202, the linear lock mechanism 204 and the busway latch mechanism 104 together constitute the interlock mechanism for providing interlock between plugging/unplugging action and ON/OFF position of the plug-in unit 104. In the exemplary embodiments two pairs of them (each pair comprising one of each of them), one pair on each side of the plug-in unit 102 have been used. The plug-in box 102 also comprises a MCCB 206 that power can be derived through the plug-in box 102 depending on the parity of the MCCB 206 viz. On, Off, Trip.
[0044] In an embodiment, as shown in FIG. 2B, each of the busway latch mechanism 104 can incorporate a latch 252 with the latch extension 108 attached to it. The latch 252 along with the latch extensions 108 can be biased by a spring (not shown here) to remain in pushed-in position but can be pulled out by latch extension 108 overcoming the biasing force of the spring. The busway latch mechanism 104 can further incorporate means to pull the latch extension 108 and thereby the latch 252 out and also to release the latch 252 and the latch extension 108 to enable them to move back to pulled-in position after proper positioning of the plug-in unit 102 on the busway 106. Releasing the latch extensions 108/latch 252 can latch the plug-in unit 102 to the busway 106.
[0045] In an embodiment, interlocking of plugging/unplugging action of the plug-in unit 102 with switching of the MCCB 206 of the plug-in unit can be achieved by preventing sliding movement of the latch 252 of the busway latch mechanism 104 when the MCCB 206 of the plug-in box is in ON position. Inability of the sliding plate 252 to slide out when the MCCB 206 is ON does not allow the plug-in unit 102 to be unplugged from the busway thus meeting the desired requirement.
[0046] In an embodiment, as shown in FIG. 2B the linear lock mechanism 204 is configured to prevent sliding movement of the latch 252 of the busway latch mechanism 104 when the MCCB 206 of the plug-in box 102 is in ON position. The linear lock mechanism 204 can incorporate a linearly travelling interlock pin 254 that engages in a corresponding hole in the latch 252 of the busway latch mechanism 104 to prevent sliding movement of the latch 252. In an aspect, the linearly travelling interlock pin 254 can travel to engage with the hole in the latch 252 when the MCCB 206/plug-in box 102 is put ON.
[0047] In an embodiment, if the plug-in box 102 is not latched to the busway 106 i.e. the latch 252 is not pushed in, the hole in the latch 252 can be out of alignment from the interlock pin which can prevent linear travel of the interlock pin 254 and consequently inability to put the MCCB 206 in ON condition.
[0048] In an embodiment, the plug-in unit 102 can be put ON only when the hole in the latch 252 and the interlock pin 254 are aligned i.e. the latch 252 is in pushed in condition. Therefore, if the plug-in box 102 is in ON position before plugging, the latch 252 cannot be pulled due to engagement of the interlock pin 254 in the hole of the latch 252. As pulling out of the latch 252 is prerequisite for positioning of the plug-in unit 102 on the busway 106, the plug-in unit 102 cannot be plugged in to the busway 106.
[0049] In an embodiment, the latch mechanism 202 can be operatively coupled to handle that actuates the MCCB 206 of the plug-in unit 102 between ON and OFF positions, and incorporate a cam 254 that, on actuation of the handle from OFF to ON position, can cause linear travel in the interlock pin 254 to engage with the corresponding hole in the latch 252 thereby preventing its sliding movement. In an alternate scenario, when the handle is actuated from ON to OFF position, the cam 256 can withdraw and allow retraction of the interlock pin 254 under force of a spring (not shown here) to disengage from the hole in the latch 252 thereby allowing the latch 252 to be pulled out to enable unplugging of the plug-in unit 102 from the busway.
[0050] FIG. 3A to 3C illustrate exemplary schematic views 300, 325 and 350 respectively showing further details of working of interlock mechanism in accordance with an embodiment of the present disclosure. As shown, the latch252 can incorporate a hole 302. The hole 302 can be out of alignment with the interlock pin 254 when the latch 252 is in pulled out condition (refer FIG. 3A). However, the two can get aligned with each other when the latch is in pushed in position and can allow the interlock pin 254 to engage with the hole 302 (as shown in FIG. 3B) when the linear lock mechanism 204 is actuated through the linear cam 258, by cam 256 of the latch mechanism 202. This situation arises when the handle 304 of the plug-in unit 102 is actuated to put the MCCB 206 it in ON position.
[0051] FIG. 3C shows another view of the interlock mechanism showing the interlock pin 254 in engagement with the latch 252 through the hole 302 in the latch 252 and the latch252 in engagement with the busway to prevent unplugging of the plug-in unit 102.
[0052] FIG. 4A and 4B illustrate exemplary isometric and exploded views 400 and 450 respectively of the busway latch mechanism 104 in accordance with an embodiment of the present disclosure. The busway latch mechanism 104 comprises a latch 252 that incorporates a hole 302. The latch 252 can be spring biased to remain in pushed in condition and can be pulled out using latch extension 108 attached to the latch 252. There can be a latch actuator 402 that can engage with the latch extension 108 and can help in pulling the latch out, and on releasing, allow the latch to go back to the pulled in position under force of the spring from the pulled out condition.
[0053] FIG. 4B shows exploded view 450 of the busway latch mechanism 104. The constituent parts of the busway latch mechanism 104 are held together in a latch base 404. The latch 252 and the latch extension 108 can be held together by means of screws 454. Spring 456 biases the latch 252/latch extension 108 in a pushed-in condition. The latch actuator 402 can be pivotally held with the latch base 404 by means of a pin 458. When a pip on the latch actuator 402 is pulled, the latch actuator 402 can move pivotally and pull the latch extension 108 out. When the latch actuator 402 is released the latch 252/latch extension 108 can return back to pushed in position under force of the spring 456.
[0054] FIG. 5A and 5B illustrate exemplary isometric and exploded views 500 and 550 respectively of linear lock mechanism 204 in accordance with an embodiment of the present disclosure. The linear lock mechanism 204 comprises the interlock pin 254 that is slidably configured in a linear block base 506 through a hole. The interlock pin 254 can be biased to remain withdrawn within the linear block base 506 by means of a spring 502. The linear cam 258 can be slidably configured with the linear block base 506 through slots in the linear block base 506 as shown in FIG. 5A. When the linear cam 258 is pushed, it can also push the interlock pin 254 to project out of the linear block base 506.
[0055] FIG. 6A and 6B illustrate exemplary isometric and exploded views respectively of latch mechanism202 in accordance with an embodiment of the present disclosure. The latch mechanism202 can be operatively coupled to handle 304 of the plug-in unit 102. The handle 304 can be in engagement with the actuating lever of the MCCB 204 of the plug-in unit 102 and can actuate the MCCB 206. When the handle 304 is moved to put the plug-in unit 102/MCCB 204 in ON position, the latch mechanism202 also moves to actuate the linear lock mechanism 204. The latch mechanism 202 incorporates cam 256 and engagement between the latch mechanism202 and the linear lock mechanism 204 is through the cam 256 that pushes the linear cam 258 of the linear lock mechanism 204 when the handle is moved to ON position. In alternate scenario when the handle is moved back to OFF position or TRIPS, the cam 256 is withdrawn back allowing the linear cam 258 also to retract back under force of the biasing spring 602.
[0056] FIG. 6B illustrates an exploded view 550 of the latch mechanism202 showing all the constituent parts of the latch mechanism202. As shown the cam 256 can be mounted on a cam support link 602 and the cam support link 602, can be in operatively coupled to the handle of the plug-in unit 102 through a plate 604. The plate can also be used to fix the handle 304 that actuates the MCCB 206.
[0057] Thus the disclosed interlock mechanism comprising at least one latch mechanism, at least one linear lock mechanism and at least one busway latch mechanism provides the desired interlock between plugging/unplugging of the plug-in unit 102 and ON/OFF status of the unit.
[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.

ADVANTAGES OF THE INVENTION
[0059] The present disclosure provides a locking mechanism for locking plug-in units with busways that ensures safety of operation.
[0060] The present disclosure provides a locking mechanism for locking plug-in units with busways that incorporates an interlocking with switching mechanism.
[0061] The present disclosure provides an interlocking mechanism that does not allow the plug-in unit to be unplugged from the busway as long as its MCCB is in an ON condition.
[0062] The present disclosure provides an interlocking mechanism that does not allow the plug-in unit to be put ON unless the plug-in unit is locked to the busway.
[0063] The present disclosure provides an interlocking mechanism that does not allow the plug-in unit to be plugged-in to the busway if the plug-in unit is in ON condition.