Claims:1. A single pole or a multiple pole circuit breaker mechanism comprising:
a housing;
one or more fixed contact means;
one or more moving contact means, said fixed contact means and said moving contact means being in operative contact with each other thereby providing a current conduction path;
a shaft assembly comprising:
at least one self-aligning floating axis double torsion spring operatively arranged inside the said shaft assembly so as to provide required contact force to maintain desired pressure between the moving contacts and the fixed contacts.
2. A single pole or a multiple pole circuit breaker mechanism comprising:
a housing;
a cover means;
one or more fixed contact means;
one or more moving contact means being shielded by means of the cover means, said fixed contact means and said moving contact means being in operative contact with each other thereby providing a current conduction path;
a shaft assembly comprising:
at least one self-aligning floating axis double torsion spring operatively arranged inside the said shaft assembly so as to provide required contact force to maintain desired pressure between the moving contacts and the fixed contacts.
3. Mechanism as claimed in claim 1 or claim 2, wherein the double torsion spring comprising plurality of arms whereby one arm is adapted to engage with the moving contact and the other arms are adapted to engaged with the rotating shaft.
4. Mechanism as claimed in claim 1 or claim 2, wherein the double torsion spring is configured to have a deflection in assembled condition so as to provide torque on moving contact ensuring the moving contact to always remain at the required position on the rotating shaft.
5. Mechanism as claimed in claim 1 or claim 2, wherein the moving contact comprising a slot means adapted to accommodate the arm of the torsion spring such that the spring is allowed to move and self-align its rotating its rotating axis in the shaft slot.
6. Mechanism as claimed in claim 2, wherein the shielded cover means is adapted to insulate the moving contact means and the said torsion spring from ionized gases of the arc.
7. Mechanism as claimed in claim 1 or claim 2, wherein the moving contact further comprising pip means.
8. Mechanism as claimed in claim 2, wherein the shield cover comprising channel like profile adapted for mounting the shield cover on pip of the moving contact.
9. A shaft assembly for use in a single pole or a multiple circuit breaker, said assembly comprising at least one self-aligning floating axis double torsion spring operatively arranged inside the said shaft assembly so as to provide required contact force to maintain desired pressure between the moving contacts and the fixed contacts of the circuit breaker during ON-OFF-Repelled condition.
, Description:TECHNICAL FIELD

[001] The present invention described herein, in general, relates to electrical switching devices such as circuit breakers, and more particularly relates to a rotating shaft assembly used in the circuit breakers wherein said rotating assembly comprises a specially designed torsion spring means.

BACKGROUND

[002] Switching devices like, circuit breaker typically have at least one solid stationary Electrical contacts coupled/uncoupled to a solid moving Electrical contact, which provides a path to carry or interrupt the electrical current in the network.

[003] Shaft construction enables the design of single break arrangement that helps in make and break of Electrical contacts (Stationary and Fixed) under normal and abnormal conditions. The shaft of the circuit breaker has to be robust as high electro dynamic repulsive forces are generated between the stationary and moving contacts in the over current conditions and for enabling the multiple switching operations.

[004] The Switching device should interrupt the over current arising due to abnormal conditions in the network, as rapidly as possible to minimize damage caused by thermal and mechanical stresses to the equipment installed downstream.

[005] In practice, extension, compression & Torsional spring are used for providing contact pressure between the Electrical fixed and moving contact, with one end of the spring hinged on the shaft and the other end to the movable electrical contact. The spring means is adapted to provide force opposing the electromagnetic during breaking of Electrical contacts at higher current fault, extension spring provides zero torque and compression spring provides reduced torque during opening of electrical contacts.

[006] US 7683281B2 / US 7709758B2 talks about the shape of shaft assembly enclosed by four walls. These packets are attached to the control mechanism via metallic links, the link is attached to the packet at one end and plates of control mechanism at the other. The same is also connected through the other link which is part of the control mechanism, the link then get connected to the shaft via pin. Here they are using compression Spring for contact pressure. However, it was not know from this prior art documents that a shaft assembly comprising a double torsion spring can be provided which can be engaged with the moving contacts without the use of any hardware components or pins. This also increases of the electrical life of the system of the present invention.

[007] Reference is made to US 20040256207 A1 which talks about the shape and assembly sequence of rotating shaft. In this prior design modular shaft is used that can assemble only on each pole. During multipole assembly they uses coupler and pins to join all modular shaft together. Such design adds to the complexity in the design for assembling each modular shaft together and increase the assembly time and cost. However, it was not know from the prior art that a single shaft assembly can be used for 1 pole or 2 poles or 3 poles or 4 poles without the use of any extra hardware or pins in the rotating shaft assembly.

[008] EP0490332 A2 discloses a mechanical and driveshaft assembly. Single shaft with same rotational axis is used with extension spring. It has been found that this assembly of the prior art requires more number of components and pin joints. However, it was not know from this prior art documents that a shaft assembly comprising a double torsion spring can be provided which can be engaged with the moving contacts without the use of any hardware components or pins. This also increases of the electrical life of the system of the present invention.

[009] There are number of shaft assembly for use in circuit breakers which have covered under patents / non patent literatures and known to exist in practice, however, in the conventional arrangement, the following drawbacks are existed which are as follows:

• Hot gases produced during short circuit test can damage the springs & jam the rotating mechanical links
• Globules produced during arcing may jam the shaft and mechanical links.
• Contact pressure for most of the configurations are provided by extension springs which are comparatively complex in construction and less accurate
• Tedious assembly procedure of compression and extension springs.
• Required more no. of components in rotating shaft assembly.
• Extension spring has less life compared to torsional spring.
• Conventional rotor shaft contains same rotating shaft axis and moving contact hinge axis.

[0010] Thus, in view of the drawbacks of the prior art as stated above, there exist a dire need to provide for a rotating shaft assembly used in the circuit breakers wherein said rotating assembly comprises a specially designed torsion spring means which adds robustness to the shaft assembly and provide multiple switching operations, ensures desired contact pressure, frictionless rotation about the axis, high opening speed of electrical moving contacts and gas sealing of the shaft assembly from high pressure ionized gases.

SUMMARY OF THE INVENTION

[0011] 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.

[0012] The first and foremost object of the present invention is to overcome all the drawbacks of the prior art.

[0013] An object of the present invention is to provide a rotating shaft assembly used in the circuit breakers wherein said rotating assembly comprises a specially designed torsion spring means which adds robustness to the shaft assembly.

[0014] Another object of the present invention is to provide a circuit breaker comprising a rotating shaft assembly used in the circuit breakers wherein said rotating assembly comprises a specially designed torsion spring means which adds robustness to the shaft assembly.

[0015] Another object of the present invention is to provide proper sealing to the shaft surface and corresponding housing surface and moving contact cover ensuring that the spring is not directly facing the arc.

[0016] Another object of the present invention is to provide an ease of assembly of self-aligning double torsion spring to have reliability in a contact rotating shaft assembly and its performance.

[0017] Another object of the present invention is to provide a contact rotating shaft for a low-voltage power circuit breaker that is assembly in a simplified manner since no pins and hardware is used with respect to the known art that is avoiding complicated joining and assembly operations.

[0018] Another object of the present invention is to provide a contact rotating shaft for a low-voltage power circuit breaker that with respect to known shaft types allows to reduce the number of constructive components required as a function of the number of poles and of the size of the circuit breaker in which it is used. This reduces overall manufacturing and assembly time for the said assembly.

[0019] Another object of the present invention is to reduce production cost and the maintenance cost of the tool since invention contains less no. of component in assembly.

[0020] Another object of the present invention is to create wiping action between moving contact and fixed contact joint by keeping shaft rotating axis and moving contact hinge axis different so during ON condition this removes unwanted oxide layers generated when contacts are in open condition for the long time. This will reduce resistance between contacts buttons

[0021] According to one aspect of the present invention there is provided a single pole or a multiple pole circuit breaker mechanism comprising:
a housing;
one or more fixed contact means;
one or more moving contact means, said fixed contact means and said moving contact means being in operative contact with each other thereby providing a current conduction path;
a shaft assembly comprising:
at least one self-aligning floating axis double torsion spring operatively arranged inside the said shaft assembly so as to provide required contact force to maintain desired pressure between the moving contacts and the fixed contacts.

[0022] According to another aspect of the present invention there is a single pole or a multiple pole circuit breaker mechanism comprising:
a housing;
a cover means;
one or more fixed contact means;
one or more moving contact means being shielded by means of the cover means, said fixed contact means and said moving contact means being in operative contact with each other thereby providing a current conduction path;
a shaft assembly comprising:
at least one self-aligning floating axis double torsion spring operatively arranged inside the said shaft assembly so as to provide required contact force to maintain desired pressure between the moving contacts and the fixed contacts.

[0023] According to another aspect of the present invention there is provided a shaft assembly for use in a single pole or a multiple circuit breaker, said assembly comprising at least one self-aligning floating axis double torsion spring operatively arranged inside the said shaft assembly so as to provide required contact force to maintain desired pressure between the moving contacts and the fixed contacts of the circuit breaker during ON-OFF-Repelled condition.

[0024] 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

[0025] 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:

[0026] Figure 1 illustrates the housing with the drive shaft assembly of the present invention.

[0027] Figures 2a and 2b illustrate the drive shaft assembly and the moving contact assembly.

[0028] Figures 3a and 3b illustrate the drive shaft assembly along with the torsion spring.

[0029] Figures 4a and 4b illustrate the moving contact and the shaft cover assembly.

[0030] Figures 5a and 5b illustrate moving contact and the cover fitments.

[0031] Figure 6 shows a cross section of the torsion spring assembly in the shaft and the moving contact in free and assembled condition.

[0032] Figure 7 shows all the essential components/parts of the assemblies of the present invention.

[0033] 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

[0034] 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.

[0035] 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.

[0036] 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.

[0037] It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] The present invention provides a single pole or a multiple pole circuit breaker mechanism. The mechanism comprises a housing, one or more fixed contact means and moving contact means. The contact means operatively engage with one another to provide a current conduction path. A shaft assembly is provided in the mechanism which comprises at least one self-aligning floating axis double torsion spring operatively arranged inside the said shaft assembly. The spring means provide required contact force to maintain desired pressure between the moving contacts and the fixed contacts.

[0042] In an embodiment of the present invention there is disclosed a single pole or a multiple pole circuit breaker mechanism. The circuit breaker mechanism comprises a housing, a cover means, one or more fixed and moving contact means. The moving contacts are shielded by means of the cover means. The shielded cover means insulates the moving contact means and the said torsion spring from ionized gases of the arc.

[0043] Fig 1 shows the perspective view of Circuit Breaker housing and shaft assembly and the cross- sectional view of current carrying path. The current conducts through the fixed electrical contact (7) and the moving electrical contact (3).

[0044] The self-aligning floating axis Double Torsion spring (4) as shown in Fig. 3 is arranged inside the shaft (2) to provide the contact force required to maintain the pressure between moving contact (3) and fixed contact (7) in ON condition. This spring has floating axis which adjusts itself during ON-OFF-Repelled condition rather than assembled in a pin. Generally, torsion spring has high life compared to extension spring that will help to achieve high electrical and Mechanical life of the circuit breaker.

[0045] Fig. 2 shows the rotating shaft assembly with moving contact assembly from the back side of the rotating shaft. Pip (33) on the moving contact (3) acts as a hinge point and rotates on the shaft surface (32) as shown in Fig. 7.

[0046] Reference is made to Fig. 3 and Fig. 7 which show the self-aligning double torsion spring (4) assembly on the moving contact (3). The spring (4) has one resting arm (41) on the moving contact (3) and other resting arm (42) on rotating shaft (2). While assembling the double torsion spring (4) from the front side of rotating shaft (2) it is to be first ensured that two arms (42) are resting on rotating shaft (2). The arm 41 as shown in the figures is operatively engaged with moving contact (3) at the slot (31) shown in Fig. 7. The slot (31) accommodates the arm (41) of the torsion spring such that the spring is allowed to move and self-align its rotating its rotating axis in the shaft slot. Double torsional spring (4) has α deflection (shown in fig 6) in assembled condition and which gives a torque on moving contact (3) that ensures moving contact will always remain at the required position on the rotating shaft. Thus double torsion spring act as a force providing member for Contact pressure and it does not allow moving contact (3) to come out from the shaft during working condition. The contacts are designed in such a way that during short circuit conditions, an electromagnetic force acts between the electrical moving contact (3) and the fixed contacts (7). This force rotates the moving contact (3) and brings it to repelled open position. This gives breaker the ability to clear very high fault. Further, the rotating shaft has different axis compared to the moving contact hinge. Such construction helps to create wiping action between the moving contact and the fixed contact joint by removing unwanted oxide layers generated when the contacts are open for long time. This reduces the MV drop further.

[0047] Fig 4. Shows each Moving contact (3) is covered with a cover (5) which is of insulating material. The shielding cover insulates moving contact body and the torsion spring from ionized gases. Moving contact (3) and moving contact cover (5) make a special arrangement (shown in Fig 4) to avoid arcing gasses and arc products entering the shaft (5) and Double torsion spring (4) in both normal ON and in repelled condition. The shielding cover (5) comprises a channel like profile for mounting the shield cover on pip of the moving contact.

[0048] Fig 5. shows moving contact (3) assembly with shielding cover (5) which protects spring and shaft from ionized gases during fault condition.

[0049] Fig. 7 shows the rotating shaft (2) comprising hollow cylindrical block (23) along the central axis. Surface (22) of the rotating shaft is meant for resting of the moving contact (3).

[0050] Advantages:

• Proper sealing corresponding to the shaft surface and corresponding housing surface and moving contact cover ensuring spring is not directly facing the arc.
• Ease of assembly of the double torsion spring to have reliability in contact rotating shaft assembly and its performance
• Life of the torsion spring is more compared to extension spring since breaker required more electrical endurance life
• Eliminates use of any pins or hardware components in the rotating shaft
• Reduction in the production cost
• Reduction in the maintenance cost
Wiping action between the moving contact and the fixed contact

[0051] The invention has been described in a preferred form only and many variations may be made in the invention which will still be comprised within its scope. The invention is not limited to the details cited above. The structure/mechanism/arrangement thus conceived is susceptible of numerous modifications and variations, all the details may furthermore be replaced with elements having technical equivalence. In practice the materials and dimensions may be any according to the requirements which will still be comprised within its true spirit.