CLIAMS:1. A circuit breaker comprising:
a first cassette having:
at least one fixed contact, at least one moving contact, at least one braid, at least one heater, at least one bimetal, at least one shaft, at least one core;
an arc chute assembly placed on said first cassette;
at least one moving core placed on said first cassette;
a second cassette enclosing said first cassette, said arc chute assembly, and said moving core, by means of at least one rivets; and
WHEREIN
at least one spring operably coupled between said second cassette and said moving core;
said heater comprises a profile accommodating said braid, thereby facilitating a moving core of a thermo-magnetic release and said moving core.

2. The circuit breaker as claimed in claim 1, wherein said moving contact is welded with braids at one end and other end of said braid is welded with said heater.

3. The circuit breaker as claimed in claim 1, wherein said heater is welded with said bimetal.

4. The circuit breaker as claimed in claim 1, wherein said moving contact is assembled inside said shaft with at least one spring for contact pressure.

5. The circuit breaker as claimed in claim 1, wherein said heater is screwed/ riveted with said fixed core.

6. The circuit breaker as claimed in claim 1, wherein said moving core of Magnetic trip system of TMR, is assembled in first cassette and second cassette of said contact system.
,TagSPECI:TECHNICAL FIELD OF THE INVENTION

[001] The present subject matter described herein, in general, relates to circuit breakers, and in particular, to an integrated assembly of circuit breaker intended to reduce assembly time and number of components.

BACKGROUND THE INVENTION

[002] Traditionally known, the role of thermo-magnetic release (TMR) is to issue trip/ break command to the circuit breaker to interrupt the circuit during overload and short circuit condition. According to the International Standard, IEC – 60947 II, the system is said to be in overload if the current in the system is > 130% of the rated current. Short circuit protection is given usually when the current exceeds more than 6 times the rated current. But there is no set definition of at what times of rated current it has to be and it varies with manufacturer and current ratings of the breaker.

[003] The overload condition of the breaker is taken care by using a Bimetal and Short circuit condition is sensed and responded using the magnetic field generated by the higher currents. Bimetal deflects with temperature rise and overload current leads to rise of temperature. The magnetic field produced at higher currents is made use of, by having a fixed core and a moving core arrangement with moving core normally being the actuator and it is connected with a spring. To perform similar function of TMR, Microprocessor release (MPR) is also used. But TMR has cost advantage over MPR.

[004] In single break system the circuit is interrupted at only one point. A copper braid is usually used to connect the moving contact with a separate component which in turn will be screwed with the TMR. This is used where cost is the primary concern. Further, in in-Direct heating method, current will not be allowed to pass through bimetal. Instead current will be passed through a separate component called Heater. The bimetal is firmly fixed with heater. At overload, the heater heats up and this heat is thermally conducted to the bimetal resulting in deflection. This method is commonly followed for higher currents. Also, in non modular construction, TMR will be devoid of cover and will be connected to the contact system. As external covers are not there, it is cheaper and less time consuming to assemble.

[005] Figure 1 shows a single break contact system with integral TMR. The figure 1 illustrates an existing MCCB, with Single break contact system and Non modular and in-direct heating philosophy TMR, is integrated in a manner where contact system and TMR are assembled separately and then brought together at a different assembly point and both are screwed together.

[006] Figure 2 shows an integral TMR having a holder component. The figure 2 illustrates, as TMR is assembled separately, a separate component called ‘holder’ is used for hinging the Moving core of the TMR and also to hold one end of the spring. The other end of the spring is hooked to the moving core. Mostly pins are used to assemble the extra component and are usually riveted to hold it in place.

[007] However, the existing products, circuit breakers, have many components involved in it, which make its working and mechanism more complex. Due to higher components, higher assembly time and labor cost is involved. Further, due to many components, there is possibility of loose connection between contact system and TMR and hence inconsistent performance over time and across different product of the same batch. Higher number of components leads to higher stack up of tolerances.

[008] In view of the above, there is a need of an improved circuit breakers that can overcome the drawbacks of the existing separate assembly of TMR with contact system known in the prior art.

SUMMARY OF THE INVENTION

[009] The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.

[0010] An object of the present invention is to provide an integrated assembly of circuit breaker intended to reduce assembly time and number of components.

[0011] Another object of the present invention is to provide an integration model of contact system with TMR.

[0012] Another object of the present invention is to provide an efficient circuit breaker with single break contact system and non modular and in-direct heating philosophy TMR.

[0013] Another object of the present invention is to reduce the number of components and processes by effectively combining the assembly of contact system with TMR.

[0014] Another object of the present invention is to replaces the use of hardware by welding and hence making an effective and consistent joint whose strength is also verifiable.

[0015] Accordingly, in one implementation, a circuit breaker is disclosed. The circuit breaker comprises a first cassette having: at least one fixed contact, at least one moving contact, at least one braid, at least one heater, at least one bimetal, at least one shaft, at least one core; an arc chute assembly placed on said first cassette; at least one moving core placed on said first cassette; a second cassette enclosing said first cassette, said arc chute assembly, and said moving core, by means of at least one rivets; and WHEREIN at least one spring operably coupled between said second cassette and said moving core; said heater comprises a profile accommodating said braid, thereby facilitating a moving core of a thermo-magnetic release and said moving core.

[0016] In one implementation, the present invention combines the assembly of contact system and TMR by modifying the heater profile and in the process also eliminating the ‘Connector’ component in contact system.

[0017] In one implementation, the present invention removes a ‘Holder’ component in TMR which was used to hold the moving core and spring by suitably providing provision in the cassette without any loss in its functional capabilities.

[0018] Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which:

[0019] Figure 1 illustrates a single break contact system with integral TMR of the prior art.

[0020] Figure 2 illustrates an integral TMR having a holder component of the prior art.

[0021] Figure 3 illustrates an overall assembly of contact system and TMR before the enclosure of cassette 2, in accordance with the subject matter of the present invention.

[0022] Figure 4 illustrates moving core holding provision in cassette 1, in accordance with the subject matter of the present invention.

[0023] Figure 5 illustrates moving core holding provision in cassette 1 in Isometric view, in accordance with the subject matter of the present invention.

[0024] Figure 6 illustrates magnetic spring holding provision in cassette 2 in Isometric view, in accordance with the subject matter of the present invention.

[0025] Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0026] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary.

[0027] Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

[0028] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

[0029] It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

[0030] By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

[0031] Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

[0032] It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0033] A person skilled in the art will appreciate that for understanding purpose the present invention is explained with the help of circuit breakers however the disclosed subject matter shall not be considered as the limiting factor for the scope of present invention.

[0034] In one implementation, the present invention revolves around lessening the assembly and number of components by modifying the profile of heater and cassettes. Instead of using a separate component ‘Connector’ to fix the braid from moving contact and further screw it to heater component of TMR (refer figure 1), the profile of the heater is modified to accommodate the braid directly (refer figure 3). This not only removes an extra component but also reduces the screwing operation as braid is directly welded to heater. Moreover, there is a possibility of screw joint getting loosened with vibration or in transit. That weak joint is replaced by a strong welding, whose strength is also verified during quality inspection. In addition to these advantages, hardware as a component is eliminated.

[0035] In one implementation, the present invention combines the assemblies of contact system and TMR, there is no need to use a separate component for hinging the moving core and hooking the spring from the moving core. This type of assembly facilitates to not only remove that extra component but also eliminates those pins which will be riveted to secure the position of that extra component. Hence the number of components and processes involved is reduced. This significantly improves the assembling time.

[0036] CONSTRUCTIONAL DETAILS: Fixed contact and Moving contact is brazed with Silver button. Moving contact is welded with braids and the other end of the braid is welded with the heater. Heater is welded with the bimetal. The moving contact is then assembled inside the shaft with springs for contact pressure. The heater is screwed/ riveted with the fixed core. Now the fixed contact and moving contact’s entire assembly is placed inside the ‘Cassette 1’. The arc chute assembly is placed on the cassette 1 in its provision. The moving core is placed on the cassette 1 in its provision. Now the ‘Cassette 2’ will enclose the cassette 1 with all the components. Both the cassettes are packed together using rivets. Then the spring is hooked on the cassette 2 as well as on the moving core.

[0037] Figure 1 illustrates a single break contact system with integral TMR.

[0038] Figure 2 illustrates an integral TMR having a holder component.

[0039] Figure 3 illustrates an overall assembly of contact system and TMR before the enclosure of cassette 2, in accordance with the subject matter of the present invention.

[0040] Figure 4 illustrates moving core holding provision in cassette 1, in accordance with the subject matter of the present invention.

[0041] Figure 5 illustrates moving core holding provision in cassette 1 in Isometric view, in accordance with the subject matter of the present invention.

[0042] Figure 6 illustrates magnetic spring holding provision in cassette 2 in isometric view, in accordance with the subject matter of the present invention.

[0043] Apart from the advantages and benefits mentioned above, other advantages and benefits are mentioned below:
· The present invention reduces the number of components/ hardware/ process.
· The present invention provides lower stack up of tolerance and hence reliable and consistent.
· The present invention reduces assembly time and number of assembly lines.
· The present invention provides lower Inventory carrying cost and space utilized.
· The present invention reduces cost of product with increased productivity.
· The present invention reduces the number of components and processes by effectively combining the assembly of contact system with TMR
· The present invention replaces the use of hardware by welding and hence making an effective and consistent joint whose strength is also verifiable.

[0044] In one implementation, the present invention reduces the use of existing component in circuit breaker and thus improving productivity and profit margin of the product. The enhancement is achieved by the profile change of a heater and by changing the assembly sequence. By profile change of heater the present invention eliminates a component called “Connector’ and hardware set (Nut, Bolt and Washer) and a weak fixing mechanism of screwing, which could get loosened with time due to vibrations or in transit, is replaced by a strong fixing mechanism, welding. Further, the TMR and contact system are assembled separately and are then screwed together. By combining the assembly sequence, a component called ‘Holder’ is removed from TMR. This has its advantages as already explained in terms of stack up, assembly time and no of lines. As a whole, the present invention provides advancement in designing the circuit breaker with the construction as disclosed above, which enables it to modify the assembly sequence and hence attain the said advantages.

[0045] Also, it is to be noted that, the profile of the heater is changed to achieve the advantages, which was not observed in any of the existing breakers and hence the inventors of this particular application provided the unique concept as disclosed in the present invention. Other than that, in none of the existing breakers, the braid is welded to TMR because of various constraints posed due to their construction and assembly sequence.

[0046] Although an improved circuit breaker have been described in language specific to structural features and/or methods, it is to be understood that the embodiments disclosed in the above section are not necessarily limited to the specific features or methods or devices described. Rather, the specific features are disclosed as examples of implementations of the improved circuit breaker.