An actuator assembly for a molded case circuit breaker (MCCB)

Abstract

Described herein is actuator assembly [112] for MCCB [100]. Actuator assembly [112] comprising pair of side frame members [118a, 118b], fork lever member [116] pivotally installed onto thereof. Fork lever member [116] defining at least two extension plate portions [116b]. Operating mechanism [114] is installed between pair of side frame members [118a, 118b], and thereof is resiliently connected to fork lever member [116], to be manipulated amongst at least ON, OFF, TRIP and RESET position. Pin member [128] is disposed between at least two extension plate portions [116b], wherein pin member [128] being adapted to engage with at least portion of operating mechanism [114], in the event of jamming of rotary contact unit of MCCB [100], thereby providing additional torque to operating mechanism [114] to be adjusted from one of the OFF position or the RESET position to ON position.

Description

[0001] AN ACTUATOR ASSEMBLY FOR A MOLDED CASE CIRCUIT BREAKER (MCCB)

[0002] TECHNICAL FIELD

[0003] The present invention generally relates to the field of circuit breakers, and more particularly, to an actuator assembly for a moulded case circuit breaker (MCCB).

[0004] BACKGROUND

[0005] This section is intended to provide information relating to the field of the invention and thus, any approach or functionality described below should not be assumed to be qualified as prior art merely by its inclusion in this section.

[0006] Circuit Breakers are electro-mechanical switching devices capable of carrying and interrupting flow of current and are also commonly known as over current protective devices. Under normal circuit conditions, a circuit breaker closes the electrical circuit, carries current for a specified time, and breaks the electrical circuit under specified abnormal circuit conditions. These over current protective devices are also employed for current interruption. Accordingly, it is said that circuit breaker is an equipment which can open or close the circuit, under all conditions viz. no load, full load, and fault conditions. Low voltage circuit breakers are commonly known to be deployed for low voltage applications, for example 1000 Volt or lower.

[0007] Various examples of low voltage circuit breakers are known, for example, a miniature circuit breaker (MCB), a moulded case circuit breaker (MCCB), a residual current circuit breaker (RCCB), an air circuit breaker (ACB), and the like. Notably, the MCB is used in applications of current rating under 125 Amperes and interrupting current rating of under 10KA, while MCCB is used in applications of current rating up to 1600 Amperes usually and interrupting current in a range of 10KA -150KA. Accordingly, it is submitted that MCCB is used for relatively high current rating applications.

[0008] Moulded case circuit breaker (MCCB) is commonly a multipolar circuit breaker, which protects the electrical network / circuit and equipment from overloading or short-circuiting. Specifically, the MCCB is capable of operating between an ON position, an OFF position, and a TRIP position. Conventionally, the MCCB includes at least a base assembly, a mid-cover assembly, a fascia plate assembly, at least one pole assembly, a TRIP assembly, and an actuator assembly. In one embodiment, the MCCB is a three-pole unit comprising of three (3) pole assemblies. In such embodiments, the base assembly, a mid-cover assembly, a fascia plate assembly, in combination with each other, forms a housing to house and support the three pole assemblies therein. Further, the actuator assembly is mounted on at least one of the three (3) pole assemblies, while the TRIP assembly is mounted on at least one of the three (3) pole assemblies, such that the three (3) pole assemblies are connected and operated together between the ON position, the OFF position, and the TRIP position. Particularly, the actuator assembly includes a lever switch that can be manually adjusted, to operate the three (3) pole assemblies together between the ON position, the OFF position, and the TRIP position.

[0009] In light of the aforementioned, it is understood that each pole assembly operates between the ON position, the OFF position, and the TRIP position. Conventionally, each of the three pole assemblies includes a casing assembly, a rotary contact unit, a stationary contact unit, and an arc chute unit. The casing assembly is a left-right type casing which includes defined sections for positioning of each of the rotary contact unit, the stationary contact unit, and the arc chute unit, such that the casing assembly houses and supports each of these components therein. The stationary contact unit is a conducting plate positioned within the casing assembly, and mostly electrically connected to a line side of the electric circuit. The rotary contact unit is a rotary assembly that is rotatably positioned within the casing assembly, and generally electrically connected to a load side of the electric circuit. The rotary contact unit can be rotated in one direction to allow the rotary contact unit to contact with the stationary contact unit, and thus resulting in the ON position of the pole assembly, further, the rotary contact unit can be rotated in opposite direction to allow the rotary contact unit to release contact from the stationary contact unit, and thus resulting in the OFF position of the pole assembly.

[0010] Moreover, the rotary contact unit is a combination of a rotary member, a rotating arm member, a metal conducting plate electrically connected to the rotating arm member, and a toggling mechanism. The rotating arm member is connected to the rotary member, by way of the toggling mechanism. Notably, the rotary member, the rotating arm member, and the toggling mechanism, are rotated together during free travel of rotary contact unit and then with respect to each other, to adjust the pole assembly between the OFF position and the ON position and vice versa. The toggling mechanism toggles the rotating arm member, to rotate in one direction, with respect to the rotating member, to adjust the pole assembly between the ON position and a BLOW OPEN position. Therefore, the rotary contact unit plays a vital role in determining the accuracy, speed, and effectiveness of adjustment of the pole assembly, between the ON position, the OFF position, and the TRIP position. Reference may be made to the following:

[0011] Publication No. CN219203071 relates to a five-connecting-rod mechanism for a circuit breaker operating mechanism, which belongs to the technical field of circuit breakers and is structurally characterized in that a transmission shaft and an output shaft are rotatably supported on a circuit breaker frame, and centers of a lock catch plate and a lock catch assembly are rotatably supported on the circuit breaker frame respectively; the output cam is fixedly sleeved on the transmission shaft, one end of the transmission crank arm is fixedly sleeved on the output shaft, the other end of the transmission crank arm is rotatably connected with one end of the connecting plate II, and the other end of the connecting plate II is in rolling contact with the outer arc surface of the output cam and is rotatably connected with one end of the connecting plate I; the other end of the connecting plate I is rotatably connected with the edge of the lock catch assembly; and the end of the lock catch plate is in rolling contact with the arc surface of the edge of the lock catch assembly. The five-connecting-rod mechanism is used as an operating mechanism of the circuit breaker, the defects and risks of large impact, short service life, high failure rate and the like of a two-connecting-rod mechanism and a four-connecting-rod mechanism are completely avoided, the service life of the structure is longer, the failure rate is lower, and reliability, practicability and safety are completely achieved.

[0012] Publication No. CN112928685 relates to a circuit breaker handcart interlocking mechanism. The circuit breaker handcart interlocking mechanism comprises a circuit breaker main shaft and a lock pin assembly, wherein the circuit breaker main shaft is rotatably arranged and is connected with a moving contact through a connecting rod assembly; the lock pin assembly comprises lock pins which are slidably arranged along a straight line, and lock holes for the lock pins to insert are arranged at a test position and a working position in a switch cabinet; a cam is arranged on the circuit breaker main shaft, and the moving direction of the lock pins is opposite to the cam; when the lock pins are inserted into the lock holes and the moving contact is located at the closing position, the long diameter part of the cam abuts against the lock pins to prevent the lock pins from exiting the lock hole; and when the moving contact is located at the opening position and the lock pins completely exit the lock holes, the lock pins abut against the short diameter of the cam to prevent the circuit breaker main shaft from rotating.

[0013] Publication No. CN205901156 relates to a direct current high speed circuit -breaker handcart, the handcart setting is in the cubical switchboard, and the handcart includes chassis, circuit breaker, contact, counter and valve. The chassis sets up between the inside wall of the cubical switchboard left and right sides to can remove in the cubical switchboard, the circuit breaker sum counter sets up on the chassis respectively, and can move together along with the chassis, and counter and circuit breaker electricity is connected, and the extension of circuit breaker rear side is provided with the contact. The setting is inlayed behind the cubical switchboard on the lateral wall to the valve, and the last border of valve is articulated with the back lateral wall of cubical switchboard to can be round border upset on it, through valve advancing mechanism swing joint between chassis and the valve. The utility model discloses compact structure, space occupy for a short time, and compare other integration circuit breaker handcarts preparation and the installation is more convenient, the cost is lower, and can be fast push or withdraw from to operating position or experiment position the direct current breaker handcart is light through valve advancing mechanism, easy operation safety, it is more reliable, change more swiftly.

[0014] Publication No. CN201562644 relates to a mechanical high-voltage circuit breaker having short circuit self-locking function, comprising a high-voltage circuit breaker body; a short circuit detection unit for detecting short circuit failure emerging from the phase line of the high-voltage circuit breaker body, and generating a cutting signal when short circuit failure occurs; a short circuit operation triggering mechanism, which is connected with the cutting mechanism within the high-voltage circuit breaker body, and triggers the cutting mechanism to perform the cutting operation when the cutting signal is received; a mechanical self-locking mechanism which causes the cutting mechanism unable to be automatically reset.

[0015] IN Publication No. 1806 / MUM / 2012 relates to a flip-flop contact locking mechanism in electrical device consists of a drive-shaft to which the upper contact is pivoted by pivot pin. Rotation of this driveshaft will cause upper moving contacts to come in contact with the lower contacts and thereby it completes the electrical circuit One end of compression spring is placed inside the spring holder and the other end is engaged to spring connector through washer. This spring connector holds two connecting link together. These links are connected to upper contact and drive-shaft through pivot pin. When the fault occurs, upward force on the upper contact will rotate the contact about pivot pin. This will cause the sliding movement of spring connector towards contact button while compressing the compression spring. After toggling point is crossed, the compression spring will release its energy and it will rotate the moving contact in upward direction till it stops over mechanism.

[0016] IN Publication No. 582 / MUM / 2011 relates to an improved operating mechanism of molded case circuit breaker. The mechanism comprises a housing, a fixed contact means, a moving contact means, a rotor means, and a mechanism module. The mechanism module comprises side plate means, trip plate means, a lower link means, an upper link means, a latch link means, a fork link means, a spring pin means, a floating pin means, navigation pin means, reset roller pin means and plurality of spring means.

[0017] Publication No. JP2009094065 relates to a circuit breaker at high current and in a short circuit state and time requiring until a contact opens. A mechanism for a circuit breaker contact arm that allows current limiting by reducing the opening time is disclosed. A contact arm is coupled to a contact arm mechanism that includes a carrier coupled to a first pair of linkages. A second pair of linkages is coupled to the first pair of linkages. A second carrier coupled to the second pair of linkages attaches to the contact arm mechanism to a main circuit breaker through a lay shaft assembly. Upon the occurrence of an undesired electrical condition, the contact arm mechanism moves from a locked position to an open position allowing the contact arm to blow open.

[0018] Publication No. RU2338289 relates to automatic circuit breaker contains flat rectangular terminals with "" shaped slots, mechanism of free release, contact system that consists of fixed contacts installed in terminals and movable contacts found in two-arm lever mounted with the possibility of interaction with fixed contacts and mechanism of free release. In the beginning and in the end of every ""-shaped slot through openings are provided. Pushers with spherical head are installed in the openings. On every pusher from the front side of terminal electroconductive and electric insulating discs are installed, and on the back side of terminal electric insulating and ferromagnetic plates are mounted. Calibrated spring is installed between plates and terminal on the pusher. At that pushers are installed with the possibility of effect at lever and at least one of pushers is connected to the mechanism of free release. Higher fast-action of automatic circuitbreaker in case of disconnection of high short-circuit currents.

[0019] Publication No. DE3208009 relates to the high-speed circuit breaker with an electrodynamic contact system having contact supports which move relative to one another, one of which is supported in a contact holder, which is connected via a switching shaft to a latching mechanism, by means of a contact shaft, such that it can rotate. According to the invention, the contact support is provided in the region of its contact shaft with two cam discs which are arranged eccentrically and are opposite one another and parallel, and whose ends facing the switching shaft are in each case provided with a cam section. By means of this measure, it is intended that the contact spring force which is detrimental to high-speed automatic contact opening should no longer counteract the opening movement of the contact support after a short opening movement and, if required, that a force component supporting the opening movement of the contact support should come into effect. Publication No. CN1304148 relates to a circuit breaker. It possesses a discrete contact capable of moving between closed position and opening position, a contact arm with a locking surface and a locking component, when the contact is opened under the state of short circuit, the locking component and locking surface are combined. Under the condition of high short-circuit the locking component can provide reliable locking, and at the same time, can reduce applied force of mechanism required for releasing contact arm.

[0020] IN Publication No. 1268 / CHE / 2012 relates to a circuit breaker includes: a movable contact terminal; a power source side fixed contact terminal and a load side fixed contact terminal; a rotor; and a contact pressure spring, which is provided to the rotor, and which is configured to apply the contact pressure to the movable contact terminal wherein the contact pressure spring is configured as a single set of pull springs, in which ends of the one side of two coils are connected to each other at a connecting portion and ends of the other side of the two coils are provided with a hook respectively, wherein respective coil portions of the pull springs is provided on respective sides of an axial direction of a rotating shaft of the movable contact terminal across the opposite face, wherein the hook is directly latched to a rib formed on the rotor so that the contact pressure is applied.

[0021] Patent No. US6479774 relates to a circuit breaker operating mechanism comprises a movable handle yoke, a mechanism spring extending in tension from the handle yoke to a pin, and a lower link extending from the pin to a crank operably connected to a contact arm bearing a movable contact. The crank is position able in open and closed positions, being in an open position when the movable contact is separated from an associated fixed contact and being in a closed position when the movable contact is mated to said associated fixed contact. The circuit breaker further comprises an interface formed on said crank and a blocking prop having a first surface that engages said interface, the first surface preventing the crank from rotating towards the closed position.

[0022] Publication No. WO03052784 relates to a current-limiting low-voltage circuit breaker comprising a contact system which is latched by a switch latch, said contact system being provided with at least one movable switch contact for each phase, said contact being able to be actuated by a drive mechanism for connection and disconnection, in addition to fixed switch contacts. The movable switch contacts of all phases can be separated from the associated fixed switch contacts when an unacceptably high current, such as a short circuit, occurs as a result of electrodynamic forces, counter to the effect of contact springs. A component whose length varies according to force is thus provided between the switch drive of the circuit breaker and the control shaft thereof.

[0023] Patent No. US4156121 relates to a molded circuit breaker case complete with line and load terminals is fashioned to house a molded case circuit breaker. Rigid conductive straps affixed to the outer case provide electrical connections between the case line and load terminals and the circuit breaker line and load terminals, respectively, and, in addition, serve to secure the circuit breaker in place. The circuit breaker operating handle protrudes through an opening in the outer case to facilitate manual circuit breaker operation.

[0024] The above listed prior arts are introduced for ease in understanding the field of the present invention. However, in the event of any known fault condition in the conventional MCCB (including, but not limited to the above listed prior arts), the rotary contact unit may get jammed, due to debris formation from melting of components, which further results in increased friction between the rotary contact unit and one or more components of the MCCB. Such increase in friction also induces substantial thermal stresses in the known actuator assembly, thereby reducing the net torque output thereof.

[0025] In view of the aforementioned limitations and various other inherent in the art, there exists a well felt need to provide a reliable, safe to operate, and improved actuator assembly of the MCCB, adapted to facilitate ease in breaking of contacts within the MCCB with minimum external force, in the event of any known fault condition, which the present disclosure aims to address.

[0026] SUMMARY OF THE INVENTION

[0027] This section is intended to introduce certain aspects of the disclosed system in a simplified form and is not intended to identify the key advantages or features of the present disclosure.

[0028] The present disclosure relates to an actuator assembly for a molded case circuit breaker (MCCB). The actuator assembly comprising a pair of side frame members, a fork lever member pivotally installed onto the pair of side frame members, the fork lever member defining at least two extension plate portions. Further, the actuator assembly comprising an operating mechanism installed between the pair of side frame members, such that the operating mechanism is resiliently connected to at least the fork lever member, to be manipulated amongst at least an ON position, an OFF position, a TRIP position, and a RESET position, and a pin member disposed between the at least two extension plate portions of the fork lever member. The pin member being adapted to engage with at least a portion of the operating mechanism, in the event of jamming of a rotary contact unit of the MCCB, thereby providing additional torque to the operating mechanism to be adjusted from one of the OFF position or the RESET position, to the ON position. In the event of switching the MCCB to the ON position immediately after a short circuit fault condition, a considerable increase in friction during manipulation of the rotary contact unit is observed. In such an event, said pin member substantially aids to overcome static & dynamic friction by particularly providing an additional torque to an upper link of the operating mechanism, to cause adjustment of the same from one of the OFF position or the RESET position to ON position.

[0029] According to an aspect of the present disclosure, the operating mechanism comprises the fork lever member, a trip arm link, an upper link, a lower link, a drive- shaft link, and a pair of flexible links.

[0030] According to another aspect of the present disclosure, the trip arm link comprises a trip arm rivet and a cut-out portion, such that the trip arm link is pivotally supported between the pair of side frame members by means of the trip arm rivet and the trip arm link is pivotally connected to the upper link.

[0031] According to yet another aspect of the present disclosure, the upper link defines a cut-out section adapted to engage with the pin member of the fork lever member, a top end of the upper link is connected to a central portion of the trip arm link by a coupling means and a bottom end of the upper link is connected to a top end of the lower link.

[0032] According to yet another aspect of the present disclosure, the lower link is pivotally connected to the drive- shaft link, such that a bottom end of the lower link is connected to a top end of the drive shaft link by means of a coupling pin.

[0033] According to yet another aspect of the present disclosure, the lower link defines a flexible link receiving portion proximal to a top end of the lower link, such that the pair of flexible links is resiliently installed in the operating mechanism.

[0034] According to yet another aspect of the present disclosure, one end of the pair of flexible links is connected to a spring receiving portion of the fork lever member and other end is connected to the flexible link receiving portion of the lower link.

[0035] According to yet another aspect of the present disclosure, the pair of side frame members have a substantially U-shaped structure, are laterally inverted to each other, and define a support bar and a semi-circular extension section, such that the semi-circular extension section adapted to engage with a pair of rivet cut-out sections of the fork lever member, to pivotally mount the fork lever member thereof.

[0036] According to yet another aspect of the present disclosure, each of the pair of side frame members define a plurality of rivet receiving cavities, adapted to rigidly receive a trip arm rivet, a trip bar rivet and a side frame member connection rivet.

[0037] According to yet another aspect of the present disclosure, the support bar eliminates displacement of various sub-assemblies of the actuator assembly housed and supported between the pair of side frame members.

[0038] According to yet another aspect of the present disclosure, the actuator assembly comprises a primary latch bracket and a trip bar pivotally and resiliently mounted on the pair of side frame members by means of the trip bar rivet and a primary latch bracket rivet.

[0039] According to yet another aspect of the present disclosure, the primary latch bracket is mounted between the operating mechanism and the trip bar, such that the primary latch bracket is adapted to engage with at least a portion of the trip arm link to latch the trip arm link to the trip bar.

[0040] According to yet another aspect of the present disclosure, the trip bar acts as a secondary latch, by engaging with at least a portion of the primary latch bracket, to further latch the combination of the trip arm link and the primary latch bracket to the trip bar.

[0041] BRIEF DESCRIPTION OF DRAWINGS

[0042] In order to explain the technical solution in the embodiments of the present application more clearly, the drawings used in the description of the embodiments will be briefly introduced below. It is obvious that the drawings in the following description are only some embodiments of the application. For those skilled in the art, without any creative work, other drawings can be obtained based on these drawings.

[0043] Figure 1 illustrates an exploded view of a moulded case circuit breaker (MCCB), in accordance with the concepts of the present disclosure.

[0044] Figure 2 illustrates an exploded view of an arrangement of an actuator assembly, three (3) pole assemblies, and a TRIP assembly of the MCCB of Figure 1, in accordance with the concepts of the present disclosure. Figure 3 illustrates a perspective view of the actuator assembly, in accordance with the concepts of the present disclosure.

[0045] Figure 4 illustrates an exploded view of the actuator assembly of Figure 3, in accordance with the concepts of the present disclosure.

[0046] Figure 5 illustrates a side view of the actuator assembly in an ON position thereof, in accordance with the concepts of the present disclosure.

[0047] Figure 6 illustrates a sectional view of the actuator assembly of Figure 5, in accordance with the concepts of the present disclosure.

[0048] DETAILED DESCRIPTION

[0049] In the following description, for the purposes of explanation, various specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. It will be apparent, however, that embodiments of the present invention may be practiced without these specific details. Several features described hereafter can each be used independently of one another or with any combination of other features. An individual feature may not address any of the problems discussed above or might address only one of the problems discussed above. Some of the problems discussed above might not be fully addressed by any of the features described herein. Exemplified embodiments of the present invention are described below, as illustrated in various drawings in which like reference numerals refer to the same parts throughout the different drawings.

[0050] Figure 1 shows an exploded view of a moulded case circuit breaker (MCCB)

[0100] , in accordance with the concepts of the present disclosure. FIG. 2 shows an exploded view of an arrangement between an actuator assembly

[0112] , three pole assemblies

[0102] , and a TRIP assembly

[0110] of the moulded case circuit breaker (MCCB)

[0100] of FIG. 1, in accordance with the concepts of the present disclosure. Figures 1 and 2 should be referred to in conjunction with each other, in order to better understand the concepts of the present disclosure. The structure and arrangement of the MCCB

[0100] will be described hereinafter in detail, while drawing references from the aforementioned accompanying drawings, wherever required.

[0051] The moulded case circuit breaker (MCCB)

[0100] is a low-voltage and high-current circuit breaker, employed to protect electrical networks / circuits from over-load or short-circuit conditions. The MCCB

[0100] is positioned between at least one load phase on a load side and at least one line phase on a line side, for providing protection during over-load or short-circuit conditions. The MCCB

[0100] operates between each of an ON position, an OFF position, and a TRIP position, wherein the MCCB

[0100] is manually adjusted between the ON position and the OFF position, whereas MCCB

[0100] is automatically adjusted to the BLOW OPEN position followed by TRIP position due to short-circuit fault at the line side or the load side of the MCCB

[0100] , In the ‘ON’ position, the MCCB

[0100] allows a flow of current therethrough, while in each of the ‘OFF’ position, the ‘BLOW OPEN’ position, and the ‘TRIP’ position, the MCCB

[0100] restricts the flow of current therethrough.

[0052] Commonly, the MCCB

[0100] is a multipolar circuit breaker. Although, in the present disclosure the MCCB

[0100] is described as a three-pole circuit breaker, it may be obvious to a person skilled in the art that the MCCB

[0100] may also be a single-pole circuit breaker, a four-pole circuit breaker, or a circuit breaker with any number of poles. The MCCB

[0100] includes three (3) pole assemblies

[0102] , a base assembly

[0104] , a mid-cover assembly

[0106] , a fascia plate assembly

[0108] , an actuator assembly

[0112] , and a TRIP assembly

[0110] .

[0053] Each of the three pole assemblies

[0102] are independent units capable of protecting the electrical networks / circuits from over-load or short-circuit conditions. In particular, each of the three pole assemblies

[0102] transmits electric current from the at least one line phase to at least one load phase, while ensuring protection from overcurrent or short-circuit along at least one load phase. Each of the three pole assemblies

[0102] operate in each of the ‘ON’ position, the ‘OFF’ position, and the ‘TRIP’ position. Notably, the three pole assemblies

[0102] are connected together with one or more components of the actuator assembly

[0112] , to adjust each of the three pole assemblies

[0102] together among the ‘ON’ position, the ‘OFF’ position, and the ‘TRIP’ position, resulting in adjustment of the MCCB

[0100] among the ‘ON’ position, the ‘OFF’ position, and the ‘TRIP’ position. A structure and arrangement of the three pole assemblies

[0102] will be described later in details.

[0054] The base assembly

[0104] is a lower structure that provides a mounting base and support structure for holding and supporting each of the three pole assemblies

[0102] therein. In particular, the base assembly

[0104] defines dedicated pole holding cavities (not shown) to mount and support each of the three pole assemblies

[0102] therein. Notably, the three pole assemblies

[0102] are fixedly attached within the pole holding cavities defined by the base assembly

[0104] by conventionally known attachment means.

[0055] The mid-cover assembly

[0106] is an upper structure that is engaged with the base assembly

[0104] , to at least partially cover the three pole assemblies

[0102] and protect the same from external environment. Usually, the mid-cover assembly

[0106] is fittingly engaged with the base assembly

[0104] , to at least partially cover the three pole assemblies

[0102] and protect the same from external environment. Notably, the mid-cover assembly

[0106] defines a mid-cover cavity [106a] to allow at least a portion of the actuator assembly

[0112] to extend therethrough.

[0056] The fascia plate assembly

[0108] is fittingly mounted on the mid-cover assembly

[0106] , to cover the mid-cover assembly

[0106] . The fascia plate assembly

[0108] defines portions to define electrical parameters related to MCCB

[0100] . Notably, the fascia plate assembly

[0108] defines a fascia plate cavity [108a], such that when assembled, the fascia plate cavity [108a] and the midcover cavity [106a], allow at least a portion of the actuator assembly

[0112] to extend therethrough, such that the portion of the actuator assembly

[0112] may be manipulated by a user between the ‘ON’ position, ‘OFF’ position & ‘TRIP’ position.

[0057] A structure and arrangement of one of the three (3) pole assemblies

[0102] will be described in detail hereinafter. Similar structure and arrangement of the remaining pole assemblies

[0102] may be envisioned. Although, the present disclosure is described as applied to the pole assembly

[0102] of single break contact type assembly, it may be obvious to a person skilled in the art that the concepts of the present disclosure may also extend to the pole assembly

[0102] of multiple break contact type assembly. The pole assembly

[0102] includes a cassette casing unit, a stationary contact unit, a rotary contact unit, and an arc chute unit.

[0058] The cassette casing unit houses and supports the stationary contact unit, the rotary contact unit, and the arc chute unit of the pole assembly. In particular, the cassette casing unit defines various dedicated sections for housing and supporting the stationary contact unit, the rotary contact unit, and the arc chute unit of the pole assembly.

[0059] The stationary contact unit is an electric contact plate structure that may be positioned within a defined portion in the cassette casing unit. In particular, in complete assembly of the MCCB

[0100] , the electrical wires from the line side are usually connected to the stationary contact unit.

[0060] The rotary contact unit is a moving structure that engages / disengages with the stationary contact unit, to allow / restrict the flow of electric current therethrough. The rotary contact unit is rotatably positioned within a defined portion in the cassette casing unit, and is provided to connect to electrical wires from the load side. Further, the rotary contact unit is rotatably adjusted while being positioned within the cassette casing unit, to make / release a contact relative to the stationary contact unit, in order to allow / restrict the flow of electric current therebetween. Notably, the rotary contact unit makes a contact relative to the stationary contact unit to allow the flow of electric current (the ‘ON’ position), the rotary contact unit releases a contact relative to the stationary contact unit, to restrict the flow of electric current (the ‘OFF’ position). Additionally, the rotary contact unit is adjusted without rotation, to release a contact relative to the stationary contact unit, to restrict the flow of electric current (the ‘BLOW OPEN’ position).

[0061] The arc chute unit is positioned within a defined portion in the cassette casing unit and comprises of a two-wall shaped arc chute holder member and an arc chute member. The arc chute holder member and an arc chute member, are arranged together, to vent out gases generated by an arc caused due to engagement / disengagement of the rotary contact unit relative to the stationary contact unit through a vent channel.

[0062] Figure 3 illustrates a perspective view of the actuator assembly

[0112] , in accordance with the concepts of the present disclosure. Figure 4 illustrates an exploded view of the actuator assembly

[0112] of Figure 3, in accordance with the concepts of the present disclosure. Figure 5 illustrates a side view of the actuator assembly, in accordance with the concepts of the present disclosure. Figure 6 illustrates a sectional view of the actuator assembly of Figure 5, in accordance with the concepts of the present disclosure. Figures 3, 4, 5, and 6 should be viewed in conjunction with each other, in order to better understand the concepts of the present disclosure. In light of the aforementioned accompanying drawings, the structure and arrangement of the actuator assembly

[0112] will be described hereinafter in detail.

[0063] The actuator assembly

[0112] is a multi-part assembly mounted on one of the pole assemblies

[0102] , and connected to the rotary contact unit of one of the pole assemblies

[0102] , by coupling means, such that the rotary contact unit of each of the three pole assemblies

[0102] are adjusted together, among the ‘ON’ position, the ‘OFF’ position, and the ‘TRIP’ position corresponding to command transmitted manually or by the TRIP assembly

[0110] . The actuator assembly

[0112] includes a fork lever member

[0116] adapted to be manually adjusted to adjust the three pole assemblies

[0102] together between the ‘ON’ position and the ‘OFF’ position. In particular, the fork lever member

[0116] of the actuator assembly

[0112] may be manipulated, to adjust the three pole assemblies

[0102] together from the ‘ON’ position to the ‘OFF’ position and vice versa. Moreover, one or more of the three pole assemblies

[0102] may be adjusted to the ‘BLOW OPEN’ position, during short-circuit fault condition in the MCCB

[0100] . Additionally, TRIP assembly

[0110] is mounted and supported on one or each of the three pole assemblies

[0102] , such that the TRIP assembly

[0110] triggers the actuator assembly

[0112] to adjust the three pole assemblies

[0102] together, from the ‘BLOW OPEN’ position to the ‘TRIP’ position. Further, the fork lever member

[0116] of the actuator assembly

[0112] may be manipulated to reset the three pole assemblies

[0102] together from the ‘TRIP’ position to the ‘OFF’ position.

[0064] The actuator assembly

[0112] comprises an operating mechanism

[0114] , a pair of side frame members [118a, 118b], a primary latch bracket

[0120] , and a trip bar

[0122] . In assembly, the operating mechanism

[0114] , the primary latch bracket

[0120] , and the trip bar

[0122] are suitably mounted between the pair of side frame members [118a, 118b], by means of a plurality of rivets, as shown in figure 4. The structure and arrangement of the operating mechanism

[0114] will be described hereinafter in detail.

[0065] The operating mechanism

[0114] comprises the fork lever member

[0116] , trip arm link [114a], an upper link [114b], a lower link [114c], a drive-shaft link [114d], and a pair of flexible links [114e]. The structure and relative arrangement of the components of the operating mechanism

[0114] will be described hereinafter in detail.

[0066] The fork lever member

[0116] defines a knob receiving portion [116a] and at least two extension plate portions [116b] extending laterally therefrom, wherein the knob receiving portion [116a] is adapted to receive a knob member

[0126] thereon, while the at least two extension plate portions [116b] define a pin member

[0128] therebetween, and a pair of pivot cut-out sections

[0130] adapted to facilitate pivotal mounting of the fork lever member

[0116] on the pair of side frame members [118a, 118b].

[0067] The trip arm link [114a] comprises a trip arm rivet [124a] of the plurality of rivets proximal to one edge thereof, and a cut-out portion

[0134] proximal to the other edge thereof, such that the trip arm link [114a] is pivotally supported between the pair of side frame members [118a, 118b], by means of the trip arm rivet [124a]. Further, the trip arm link [114a] is pivotally connected to the upper link [114b], such that a top end of the upper link [114b] is connected to a central portion of the trip arm link [114a], by coupling means (not shown). The coupling means is one of a rivet coupling means, a pin coupling means, bolt and screw coupling means and combinations thereof.

[0068] The upper link [114b] defines a cut-out section

[0132] adapted to engage with the pin member

[0128] of the fork lever member

[0116] , upon manipulation of the fork lever member

[0116] from the ‘ON position’ to the ‘OFF’ position thereof. The upper link [114b] is further pivotally connected to the lower link [114c], such that a top end of the lower link [114c] is in connection with a bottom end of the upper link [114b]. The lower link [114c] is pivotally connected to the drive- shaft link [114d], such that a bottom end of the lower link [114c] is connected to a top end of the drive-shaft link [114d] . In particular, the rotary contact unit pivoted within the cassette casing unit of the MCCB

[0100] acts as the drive-shaft link [114d], and the lower link [114c] is pivotally connected to the drive-shaft link [114d], by means of a coupling pin which is also used for coupling the rotary contact unit of each of the three (3) pole assemblies

[0102] of the MCCB

[0100] , as seen from figures 2 and 4.

[0069] The lower link [114c] defines a flexible link receiving portion [114f], proximal to the top end thereof, such that the pair of flexible links [114e] is resiliently installed in the operating mechanism

[0114] , by engaging one end of the pair of flexible links [114e] with a spring receiving portion [116c] of the fork lever member

[0116] , while engaging the other end thereof with the flexible link receiving portion [114f] of the lower link [114c].

[0070] With such an arrangement of the operating mechanism

[0114] , as described hereinabove in light of figures 4 and 5, upon manipulation of the fork lever member

[0116] from the ‘ON’ position to the ‘OFF’ position thereof, the pin member

[0128] of the fork lever member

[0116] engages with the cut-out section

[0132] of the upper link [114c] causing a pivotal movement thereof, which further causes a pivotal movement of the lower link [114c], to finally rotate the drive-shaft link [114d], to further manipulate the rotary contact unit of each of the three pole assemblies

[0102] from the ‘ON’ position to the ‘OFF’ position thereof, respectively. Herein, the ‘ON’ position refers to a position of the rotary contact unit, wherein the rotary contact unit is in contact with the stationary contact unit, thereby allowing the flow of current therethrough, while the ‘OFF’ position refers to a position of the rotary contact unit, wherein the rotary contact unit is not in contact with the stationary contact unit, thereby disrupting the flow of current therethrough. Such positions of the rotary contact unit are commonly known to a person skilled in the art, and therefore, are not represented in the accompanying figures. Notably, the pin member

[0128] remains inactive during normal operations of the MCCB

[0100] . The pin member

[0128] only comes in contact with any component of the operating mechanism

[0114] , in the event of short circuit fault condition, wherein the rotary contact unit gets jammed in the ‘OFF’ position thereof, and the operating mechanism

[0114] is unable to be manipulated even after crossing the toggle point thereof.

[0071] As seen from figures 3, 5, and 6, the trip bar

[0122] and the primary latch bracket

[0120] are pivotally and resiliently mounted on the pair of side frame members [118a, 118b], by means of a trip bar rivet [124b] and a primary latch bracket rivet [124d], respectively. In particular, the primary latch bracket

[0120] is mounted between the operating mechanism

[0114] and the trip bar

[0122] . Notably, the primary latch bracket

[0120] is adapted to engage with at least a portion of the trip arm link [114a] of the operating mechanism

[0114] , to latch the trip arm link [114a] thereto. Further, the trip bar

[0122] acts as a secondary latch, by engaging with at least a portion of the primary latch bracket

[0120] , to further latch the combination of trip arm link [114a] and the primary latch bracket

[0120] thereto.

[0072] The pair of side frame members [118a, 118b] employed in the operating mechanism

[0114] , may or may not be identical and laterally inverted to each other, and have a substantially U-shaped structure, as seen from figure 4. In particular, each of the pair of side frame members [118a, 118b] defines a plurality of rivet receiving cavities [118c, 118d, 118e, 118h] adapted to rigidly receive the trip arm rivet [124a], the trip bar rivet [124b], and a side frame member connection rivet [124c], respectively. Further, the pair of side frame members [118a, 118b] define a semicircular extension section [118f] adapted to engage with the pair of pivot cut-out section

[0130] of the fork lever member

[0116] , to pivotally mount and support the fork lever member

[0116] thereof. In addition to the above, the pair of side frame members [118a, 118b] define a support bar [118g] for eliminating displacement of various components / sub-assemblies of the actuator assembly

[0112] housed and supported between the pair of side frame members [118a, 118b], caused due to shocks and vibrations arising from the short circuit fault condition. With such features, the pair of side frame members [118a, 118b] are capable of being rigidly connected to each other, for facilitating the mounting of the operating mechanism

[0114] , the trip bar

[0122] , and the primary latch bracket

[0120] , as seen from figures 3, 5, and 6.

[0073] Advantageously, the components / sub-assemblies of the actuator assembly

[0112] are optimally designed to possess substantially high structural strength and rigidity resulting in enhanced overall durability of the actuator assembly

[0112] . The components of the operating mechanism

[0114] of the actuator assembly

[0112] are suitably designed and arranged with respect to each other, such that the actuator assembly

[0112] is capable of being adjusted in either two or three stable conditions, based on its application. Moreover, the operating mechanism

[0114] remains stable in its position till the toggle point thereof, while the user performs either of an OFF operation or an ON operation thereon, and direction of torque changes on the components of the operating mechanism

[0114] , beyond the toggle point thereof.

[0074] In the event the operating mechanism

[0114] or the rotary contact unit is jammed, the pin member

[0128] provided in the operating mechanism

[0114] substantially increases the net torque on the drive shaft link [114d], to meet the high torque requirement associated with the increase in friction between the drive-shaft link [114d] and one or more components of the pole assembly

[0102] . In particular, the cut-out section

[0132] of the upper link [114b] of the operating mechanism

[0114] as well as the cut-out portion

[0134] of the trip arm link [114a], ensures that there is no engagement between one or more components of the actuator assembly

[0112] and the pin member

[0128] of the fork lever member

[0116] , during normal operating conditions of the MCCB

[0100] . The operating mechanism

[0114] of the present invention increases the reliability of the MCCB

[0100] , and also helps in substantially increasing the short-circuit breaking capacity of the MCCB

[0100] . In the event of switching the MCCB

[0100] to the ON position immediately after a short circuit fault condition, a considerable increase in friction during manipulation of the rotary contact unit is observed. In such an event, said pin member substantially aids to overcome static & dynamic friction by particularly providing an additional torque to an upper link of the operating mechanism, to cause adjustment of the same from one of the OFF position or the RESET position to ON position.

[0075] While the preferred embodiments of the present invention have been described hereinabove, it should be understood that various changes, adaptations, and modifications may be made therein without departing from the spirit of the invention. It will be obvious to a person skilled in the art that the present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive.

[0076] LIST OF REFERENCE NUMERALS

[0077] 100 - Moulded case circuit breaker (MCCB)

[0078] 102 - Pole assemblies

[0079] 104 - Base assembly

[0080] 106 - Mid -cover assembly

[0081] 108 - Fascia plate assembly

[0082] 110 - TRIP assembly

[0083] 112 - Actuator assembly

[0084] 114 - Operating mechanism

[0085] 114a - Trip arm link b - Upper link c - Lower link d - Drive shaft link e - Pair of flexible links f - Flexible link receiving portion - Fork lever member a - Knob receiving portion b - two extension plate portions c - Spring receiving portion a, 118b - Pair of side frame members c, 118d, 118e, 118h - Rivet receiving cavitiesf - Semi-circular extension section g - Support bar - Primary latch bracket - Trip bar a - Trip arm rivet b - Trip bar rivet c - Side frame member connection rivet d - Primary latch bracket rivet - Knob member - Pin member - Pair of pivot cut-out sections 132 - Cut-out section

[0086] 134 - Cut-out portion

Claims

I / We Claim:

1. An actuator assembly [112] for a molded case circuit breaker (MCCB) [100], the actuator assembly [112] comprising: a pair of side frame members [118a, 118b]; a fork lever member [116] pivotally installed onto the pair of side frame members [118a, 118b], the fork lever member [116] defining at least two extension plate portions [116b]; an operating mechanism [114] installed between the pair of side frame members [118a, 118b], such that the operating mechanism [114] is resiliently connected to the fork lever member [116], to be manipulated amongst at least an ON position, an OFF position, a TRIP position, and a RESET position; and a pin member [128] disposed between the at least two extension plate portions [116b] of the fork lever member [116], the pin member [128] being adapted to engage with at least a portion of the operating mechanism [114], in the event of jamming of a rotary contact unit of the MCCB [100], thereby providing additional torque to the operating mechanism [114] to be adjusted from one of the OFF position or the RESET position, to the ON position.

2. The actuator assembly [112] as claimed in claim 1, the operating mechanism [114] comprises the fork lever member [116], a trip arm link [114a], an upper link [114b], a lower link [114c], a drive- shaft link [ 114d] , and a pair of flexible links [114e].

3. The actuator assembly [112] as claimed in any of the claims 1 or 2, wherein the trip arm link [114a] comprises a trip arm rivet [124a] and a cut-out portion [134], such that the trip arm link [114a] is pivotally supported between the pair of side frame members [118a, 118b] by means of the trip arm rivet [124a] and the trip arm link [114a] is pivotally connected to the upper link [114b].

4. The actuator assembly [112] as claimed in any of the claims 1 or 2, wherein the upper link [114b] defines a cut-out section [132] adapted to engage with the pin member [128] of the fork lever member [116], a top end adapted to be connected to a central portion of the trip arm link [114a] by a coupling means, and a bottom end adapted to be connected to a top end of the lower link [114c].

5. The actuator assembly [112] as claimed in any of the claims 1 or 2, wherein the lower link [114c] is further pivotally connected to the drive- shaft link [ 114d] , such that a bottom end of the lower link [114c] is connected to a top end of the drive shaft link [114d] by means of a coupling pin.

6. The actuator assembly [112] as claimed in any of the claims 1, 2, or 5, wherein the lower link [114c] defines a flexible link receiving portion [ 114f] proximal to a top end of the lower link [114c], such that the pair of flexible links [114e] is resiliently installed in the operating mechanism [114].

7. The actuator assembly [112] as claimed in any of the claims 1 or 6, wherein one end of the pair of flexible links [ 114e] is connected to a spring receiving portion [116c] of the fork lever member [116] and other end is connected to the flexible link receiving portion [114f] of the lower link [114c].

8. The actuator assembly [112] as claimed in claim 1, wherein the pair of side frame members [118a, 118b] have a substantially U-shaped structure, are laterally inverted to each other, and define a support bar [118g] and a semi-circular extension section [118f], such that the circular extension section [118f] is adapted to engage with a pair of rivet cut-out section [130] of the fork lever member [116], to pivotally mount the fork lever member [116] thereon.

9. The actuator assembly [112] as claimed in any of the claims 1 or 8, wherein each of the pair of side frame members [118a, 118b] define a plurality of rivet receiving cavities [118c, 118d, 118e, 118h], adapted to rigidly receive a trip arm rivet [124a], a trip bar rivet [124b], and a side frame member connection rivet [124c].Dated this 12thday of April 2024(GARIMA SAHNEY) IN / PA-1826 AGENT FOR THE APPLICANT(S) OF SAIKRISHNA & ASSOCIATES

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