FIELD OF THE INVENTION

The invention pertains to an improved & simplified multi-function Miniature Circuit Breaker having only Two-lever-assembly & other features. The two-lever mechanism enables mechanical ON-OFF with trip-free feature, true contact position, sort circuit indication test button mechanism verification, auto-resetting, thermal tripping, magnetic tripping, multipole coupling and auxiliaries/accessories coupling.

BACKGROUND OF THE INVENTION

Circuit breakers protect electrical circuits from damage caused by current surges by interrupting or breaking the current path between the input terminals and output terminals. A conventional miniature circuit breaker comprises a pair of contacts located in a main current path between a line terminal for connecting to a power supply and a load terminal for connecting to a load to be powered by the power supply.

The conventional miniature circuit breaker further includes a mechanism by which the miniature circuit breaker can be operated and gets signal from thermal and magnetic releases for the circuit protection during abnormal conditions or faults. These mechanisms are typically complex in nature as they have to provide many functions while operating with optimum forces with the least tripping force and optimum contact pressure. At the same time, higher velocity is required to break the arc faster during short-circuit.

A conventional mechanism involves: a manual operating handle coupled to a connecting rod at one end and at the other end, connected to a jump-knuckle. The jump-knuckle is connected to the tripping lever which gets signals from the thermal and magnetic release in case of fault, resulting in automatic tripping of the mechanism, independently from the handle, known as trip-free feature... The moving contact is mounted on Contact support lever and rotates along-with the Contact support lever.

A device of this kind wherein a jump-knuckle lever is constituted with a hole designed to engage directly with the connecting rod end. A mechanism of this kind is a "watchmechanism", making it difficult to manufacture, involving 3 or more levers making it time- consuming to assemble. The object of the invention consists a miniature circuit breaker mechanism comprising minimum number of components making it easy to manufacture and assemble while operating with optimum forces,

This background information is provided to make known information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention.

Abstract:

The invention pertains to an improved & simplified operating mechanism of a miniature circuit breaker having only Two-lever-assembly. The two-lever mechanism enables mechanical ON- OFF positions which is the main function to determine and to control the breaker whether to make it in a close(ON) or open(OFF) with trip-free feature. The trip-free feature ensures positive tripping in the case of fault even if the handle is forcefully held in ON position (closed loopJ.Also, a true contact position indication is inbuilt in the 2-lever mechanism, where it will show the status of the loop inside the breaker irrespective of the handle position weather its ON or OFF. In addition, a short circuit fault indication has been added to help understand the breaker has been tripped because of fault or it has been made off for maintenance purpose. Moreover, Test button for the mechanism is added to offer a mechanical verification of the trip function of the MCE during routine testing or when the MCE is stacked in the panel. The improved 2-lever-mechanism has also the thermal tripping feature which is covering one of the main functions to provide protection during over-load fault condition as well as the magnetic tripping which will efficiently receive the signal from the magnetic in any short-circuit faults. The improved 2-lever-mechanism has the ability to connect a multipole coupling as well as the auxiliaries/accessories coupling features. The beauty of the improved two lever mechanism is that, along with multiple features it is easy for manufacturing and assembly coupled with the optimum forces, minimum trip-force and optimum contact pressure. , while clearing the fault quickly through the figure -like profile.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an improved simplified mechanism device for a miniature circuit breaker and miniature circuit breaker comprising the same. The current prior art is an improvement over Patent Publication No. 1049778 & IN201917047208. Multiple profiles have been added to the 2-lever mechanism to achieve multiple functions and features, while making it easy for manufacturing, assembly and optimum forces. This prior-art also has a claim that is improvement over prior-art EP1703533A2. The short-circuit feature is achieved using only 2 components ensuring ease of assembly whereas EP1703533A2 uses 3 components. Embodiments of the invention will now be described, by way of example only, by reference to the attached Figures, wherein:

Figure 1: illustrates a miniature circuit breaker in accordance with aspects of the invention detailing the components which are the handle spring (1), handle (2), connect rod (3), contact support spring (4), contact support lever (5), mechanism spring(6), base [7], moving contact sub-assembiy(8), moving contact spring (9), tripping lever(lO), holding spring(ll), and thermal slider(12) , short circuit indication(13)&(14)

Figure 2: illustrates components of the 2-lever mechanism and the associated components when the miniature circuit breaker is in open loop position (OFF).

Figure 3: illustrates components of the 2-lever mechanism and the associated components when the miniature circuit breaker is in closed loop position (ON).

Figure 4: illustrates components of the 2-lever mechanism and the associated components when the miniature circuit breaker in at trip-free position, while the ON-OFF operation the two lever allows the mechanism to have a trip-free feature along with resetting.

Figure 5: illustrates the auxiliaries coupling position with the 2-lever mechanism component.

Figure 6: illustrates the multipole-coupling position with the 2-lever mechanism component.

Figure 7: illustrates the simplified 2-lever assembly

Figure 8: : illustrates aspects of the invention detailing to one of the components of the simplified 2-lever mechanism which is the contact support lever, as it shown in figure (1) that contact support will be assembled on the base (7) by the mechanism pin (6) through the center of contact support (5.2) which is also the mechanism pivot center, the radial rotation of the contact support lever(5) controlled by the handle (2) and through connect rod(3).

When miniature circuit breaker is switched to OFF position, the rotation of the contact support lever(5) has a stopper in the base(7) which makes the mechanism stops positively on the mating surface in the contact support (5.1). also shown the shaft (5.3) projected on the contact support lever for the moving contact sub-assembly (8) from the top, making it easy for automatic assembly. A stopper maintained to reduce the bouncing of the moving contact (5.8) also having another stopper (5.9) to reduce the swing during normal OFF or fault condition and will be locked by the moving contact spring [9] which has 2-stoppers, one end will be assembled in the contact support (5.4) and the other end in the moving contact (8). Part of that the bottom side of contact support lever will have the opening spring (4) assembled at the center surface of the contact support (5.5) and Socked by 2-arm, one arm stopped at the top of contact support center (5.7) and other arm stopped at the bottom center of the contact support (5.6), Once assembled in the base (7), one arm of the spring resting on (5.7), will rest on the base stopper, last but not the least, the top surface in the contact support lever (5.11) act as indication feature with green (OFF) and red (ON indication.

Figure 9: Illustrates aspects of the invention detailing the other component of the simplified 2-levers which is the tripping lever(lO), as it shown in figure (1) tripping Iever(10) assembly at the top of the contact support lever(5) by the mechanism pin (6) through the center (10.4), which is also the mechanism pivot center and locked by the holding spring(ll) which has 2- arms, one arm will be stopped by tripping lever spring stopper(10.6) and other arm stopped by the spring stopper at contact support lever (5.10). However, The magnetic and thermal fault signals occurs in the back wall of the tripping lever (10.8) and thermal slider slot (10.5) respectively. At the tripping lever shown in figure [5] and figure [6] slot connectors for Auxiliaries and multipole-coupling shown in (10.3) and (10.7) respectively. The lifting feature to lift the connect rod (3) to come out and to de-latches the miniature circuit breaker is the finger like feature (10.1). An extended profile (10.2) is maintained in the tripping lever to provide ingress protection.

Figure 11 : illustrates aspects of the invention of the din-rail holder added with a sliding feature. This feature enables easy replacement/maintenance of the MCB when stacked along with other MCBs in the panel, especially when the panel is wired. The sliding feature enables, the MCB to slide 'when un-screwed from the busbar panel and as a result it can be removed without having to remove the other MCBs.

DETAILED DESCRIPTION OF THE INVENTION

This invention provides a miniature circuit breaker shown in figure (1) having a simplified 2- lever mechanism (5&10) that efficiently obtain multiple functions in 1 assembly which contains only two levers. The simplified 2-lever mechanism enables mechanical ON-OFF operation with trip-free feature, true contact position, ON-OFF indication, auto-resetting, thermal tripping, magnetic tripping, multipole coupling and auxiliaries /accessories coupling. Referring to the figures, a miniature circuit breaker figure (1) is provided with 2-lever assembly (7) to obtain the functions/features. The miniature circuit breaker (1) comprises a housing or casing, optionally provided in two connectable halves, and the breaker assembly provides a main current path between the input terminal and the output terminal. Housing or casings are generally plastic and include appropriate mounting and insulation elements. The miniature circuit breaker assembly includes mechanical mechanism shown in figure (7), operatively connected to a hanclle(2), connect rod(3), contact support lever(5), tripping lever(lO) and moving contact sub-assembly (8). The handle assembly is movable between a normal and abnormal or fault position (indicative of the circuit being tripped] and includes the operator or handle (2) and associated handle spring (1). The handle assembly is connected to the contact support lever(5) and tripping lever(lO) by the connect rod (4]

The handle spring (1) is configured to bring the handle(2) to the OFF position when the miniature circuit breaker (1) is tripped as illustrated in figures (1) and (2)

As illustrated in the figures, the 2-lever assembly shown in figure(7) will be controlled by the connect rod(3), and held by holding spring(ll) to join the 2-lever in one rotation path, whenever the miniature circuit breaker at ON position shown in figure(2) the 2-lever assembly will be rotated in a certain angle that will allow the moving contact to be contacting with the magnetic assembly to make the current passing though, Under abnormal /fault condition, magnetic will release the tripping lever by pushing the backwall of the tripping lever [10.8] as a result, the trip lever is configured to transform the linear force that coming from magnetic assembly to rotary force to open the mechanism, when the opening mechanism is activated, the finger like profile (10.1) in the tripping lever pushing the connect rod [3] quickly to release the mechanism and trip the breaker, the contact support lever (5) rotates counterclockwise along with the moving contact sub-assembly (8)

Referring to figure(l), the contact support lever (5] includes an opening spring [4] that will be assembled at surface of the contact support (5.5) toward the back-side as illustrated in figure(8) The opening spring (4) along with the 2-lever mechanism, stores the energy while in ON-OFF condition & during the fault condition, facilitates separation of the contacts by providing the required opening velocity for rotating the moving contact sub-assembly (8) during TRIP operation. A test button (15) is coupled with the 2-lever mechanism to achieve a unique functionality of "trip-verification" This function is useful to verify the healthiness of the tripping mechanism. Such verification can be used during the routine testing as well as during installations/maintenance. The access of the test button is such that it is very easy to test the healthiness of the tripping mechanism even when the MCB is stacked in the electric distribution panel.

A short circuit trip indication (13)&(14) where both assembled in base(7) to provide dear identification about the fault condition. It becomes very tricky for a skilled person to identify if the MCB was tripped or it was switched off. To distinguish this condition, a short-circuit trip indication (13) & (14) is added in the improved 2-lever mechanism.

For abnormai/fault thermal condition, a signal will be sent from the thermal sub-assembly (8) to tripping lever (10.5), through the thermal slider rod (12), the trip lever is configured to transform the linear force that is coming from the thermal slider rod(12) to a rotary force acting on thermal slider slot (10.5), the thermal element(13) will rotate clockwise direction and forcibly pushing the thermal slider, the thermal slider will transform the rotary force coming from the thermal element(13) to a linear force as a result the tripping lever will move Counterclockwise to open the mechanism, when the opening mechanism is activated, as we explained previously, finger like feature (10.1) pushing the connect rod (3) to release the mechanism and trip the breaker. Having such metal thermal slider/rod will have robust calibration as well as less possibility of melting of the plastic coming in contact with heater element

Referring figure (10), an Auxiliaries -coupling can be connected through tripping lever Auxiliaries slot (10.3) as it’s shown in figure (5) as well as multipole-coupling which also can be connected through multipole slot (10.7) as it is shown in figure(6).